Understanding Recurrent Crime as System-Immanent Collective Behavior

PubMed Central

Perc, Matjaž; Donnay, Karsten; Helbing, Dirk

2013-01-01

Containing the spreading of crime is a major challenge for society. Yet, since thousands of years, no effective strategy has been found to overcome crime. To the contrary, empirical evidence shows that crime is recurrent, a fact that is not captured well by rational choice theories of crime. According to these, strong enough punishment should prevent crime from happening. To gain a better understanding of the relationship between crime and punishment, we consider that the latter requires prior discovery of illicit behavior and study a spatial version of the inspection game. Simulations reveal the spontaneous emergence of cyclic dominance between “criminals”, “inspectors”, and “ordinary people” as a consequence of spatial interactions. Such cycles dominate the evolutionary process, in particular when the temptation to commit crime or the cost of inspection are low or moderate. Yet, there are also critical parameter values beyond which cycles cease to exist and the population is dominated either by a stable mixture of criminals and inspectors or one of these two strategies alone. Both continuous and discontinuous phase transitions to different final states are possible, indicating that successful strategies to contain crime can be very much counter-intuitive and complex. Our results demonstrate that spatial interactions are crucial for the evolutionary outcome of the inspection game, and they also reveal why criminal behavior is likely to be recurrent rather than evolving towards an equilibrium with monotonous parameter dependencies. PMID:24124533

Functional Resistance to Recurrent Spatially Heterogeneous Disturbances Is Facilitated by Increased Activity of Surviving Bacteria in a Virtual Ecosystem

PubMed Central

König, Sara; Worrich, Anja; Banitz, Thomas; Harms, Hauke; Kästner, Matthias; Miltner, Anja; Wick, Lukas Y.; Frank, Karin; Thullner, Martin; Centler, Florian

2018-01-01

Bacterial degradation of organic compounds is an important ecosystem function with relevance to, e.g., the cycling of elements or the degradation of organic contaminants. It remains an open question, however, to which extent ecosystems are able to maintain such biodegradation function under recurrent disturbances (functional resistance) and how this is related to the bacterial biomass abundance. In this paper, we use a numerical simulation approach to systematically analyze the dynamic response of a microbial population to recurrent disturbances of different spatial distribution. The spatially explicit model considers microbial degradation, growth, dispersal, and spatial networks that facilitate bacterial dispersal mimicking effects of mycelial networks in nature. We find: (i) There is a certain capacity for high resistance of biodegradation performance to recurrent disturbances. (ii) If this resistance capacity is exceeded, spatial zones of different biodegradation performance develop, ranging from no or reduced to even increased performance. (iii) Bacterial biomass and biodegradation dynamics respond inversely to the spatial fragmentation of disturbances: overall biodegradation performance improves with increasing fragmentation, but bacterial biomass declines. (iv) Bacterial dispersal networks can enhance functional resistance against recurrent disturbances, mainly by reactivating zones in the core of disturbed areas, even though this leads to an overall reduction of bacterial biomass. PMID:29696013

Arbuscular mycorrhizal fungi improve photosynthetic energy use efficiency and decrease foliar construction cost under recurrent water deficit in woody evergreen species.

PubMed

Barros, Vanessa; Frosi, Gabriella; Santos, Mariana; Ramos, Diego Gomes; Falcão, Hiram Marinho; Santos, Mauro Guida

2018-06-01

Plants suffer recurrent cycles of water deficit in semiarid regions and have several mechanisms to tolerate low water availability. Thus, arbuscular mycorrhizal fungi (AMF) can alleviate deleterious effects of stress. In this study, Cynophalla flexuosa plants, a woody evergreen species from semiarid, when associated with AMF were exposed to two consecutive cycles of water deficit. Leaf primary metabolism, specific leaf area (SLA), leaf construction cost (CC) and photosynthetic energy use efficiency (PEUE) were measured. The maximum stress occurred on seven days (cycle 1) and ten days (cycle 2) after suspending irrigation (photosynthesis close to zero). The rehydration was performed for three days after each maximum stress. In both cycles, plants submitted to water deficit showed reduced gas exchange and leaf relative water content. However, Drought + AMF plants had significantly larger leaf relative water content in cycle 2. At cycle 1, the SLA was larger in non-inoculated plants, while CC was higher in inoculated plants. At cycle 2, Drought + AMF treatment had lower CC and large SLA compared to control, and high PEUE compared to Drought plants. These responses suggest AMFs increase tolerance of C. flexuosa to recurrent water deficit, mainly in cycle 2, reducing the CC, promoting the improvement of SLA and PEUE, leading to higher photosynthetic area. Thus, our result emphasizes the importance of studies on recurrence of water deficit, a common condition in semiarid environments. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Electrogram morphology recurrence patterns during atrial fibrillation.

PubMed

Ng, Jason; Gordon, David; Passman, Rod S; Knight, Bradley P; Arora, Rishi; Goldberger, Jeffrey J

2014-11-01

Traditional mapping of atrial fibrillation (AF) is limited by changing electrogram morphologies and variable cycle lengths. We tested the hypothesis that morphology recurrence plot analysis would identify sites of stable and repeatable electrogram morphology patterns. AF electrograms recorded from left atrial (LA) and right atrial (RA) sites in 19 patients (10 men; mean age 59 ± 10 years) before AF ablation were analyzed. Morphology recurrence plots for each electrogram recording were created by cross-correlation of each automatically detected activation with every other activation in the recording. A recurrence percentage, the percentage of the most common morphology, and the mean cycle length of activations with the most recurrent morphology were computed. The morphology recurrence plots commonly showed checkerboard patterns of alternating high and low cross-correlation values, indicating periodic recurrences in morphologies. The mean recurrence percentage for all sites and all patients was 38 ± 25%. The highest recurrence percentage per patient averaged 83 ± 17%. The highest recurrence percentage was located in the RA in 5 patients and in the LA in 14 patients. Patients with sites of shortest mean cycle length of activations with the most recurrent morphology in the LA and RA had ablation failure rates of 25% and 100%, respectively (hazard ratio 4.95; P = .05). A new technique to characterize electrogram morphology recurrence demonstrated that there is a distribution of sites with high and low repeatability of electrogram morphologies. Sites with rapid activation of highly repetitive morphology patterns may be critical to sustaining AF. Further testing of this approach to map and ablate AF sources is warranted. Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Recurrence in truncated Boussinesq models for nonlinear waves in shallow water

NASA Technical Reports Server (NTRS)

Elgar, Steve; Freilich, M. H.; Guza, R. T.

1990-01-01

The rapid spatial recurrence of weakly nonlinear and weakly dispersive progressive shallow-water waves is examined using a numerical integration technique on the discretized and truncated form of the Boussinesq equations. This study primarily examines recurrence in wave fields with Ursell number O(1) and characterizes the sensitivity of recurrence to initial spectral shape and number of allowed frequency modes. It is shown that the rapid spatial recurrence is not an inherent property of the considered Boussinesq systems for evolution distances of 10-50 wavelengths. The main result of the study is that highly truncated Boussinesq models of resonant shallow-water ocean surface gravity waves predict rapid multiple recurrence cycles, but that this is an artifact dependent on the number of allowed modes. For initial conditions consisting of essentially all energy concentrated in a single mode, damping of the recurrence cycles increases as the number of low-power background modes increases. When more than 32 modes are allowed, the recurrence behavior is relatively insensitive to the number of allowed modes.

Palbociclib in Treating Patients With Relapsed or Refractory Rb Positive Advanced Solid Tumors, Non-Hodgkin Lymphoma, or Histiocytic Disorders With Activating Alterations in Cell Cycle Genes (A Pediatric MATCH Treatment Trial)

ClinicalTrials.gov

2018-06-13

Advanced Malignant Solid Neoplasm; RB1 Positive; Recurrent Childhood Ependymoma; Recurrent Ewing Sarcoma; Recurrent Glioma; Recurrent Hepatoblastoma; Recurrent Kidney Wilms Tumor; Recurrent Langerhans Cell Histiocytosis; Recurrent Malignant Germ Cell Tumor; Recurrent Malignant Glioma; Recurrent Medulloblastoma; Recurrent Neuroblastoma; Recurrent Non-Hodgkin Lymphoma; Recurrent Osteosarcoma; Recurrent Peripheral Primitive Neuroectodermal Tumor; Recurrent Rhabdoid Tumor; Recurrent Rhabdomyosarcoma; Recurrent Soft Tissue Sarcoma; Refractory Ependymoma; Refractory Ewing Sarcoma; Refractory Glioma; Refractory Hepatoblastoma; Refractory Langerhans Cell Histiocytosis; Refractory Malignant Germ Cell Tumor; Refractory Malignant Glioma; Refractory Medulloblastoma; Refractory Neuroblastoma; Refractory Non-Hodgkin Lymphoma; Refractory Osteosarcoma; Refractory Peripheral Primitive Neuroectodermal Tumor; Refractory Rhabdoid Tumor; Refractory Rhabdomyosarcoma; Refractory Soft Tissue Sarcoma

Island-Model Genomic Selection for Long-Term Genetic Improvement of Autogamous Crops.

PubMed

Yabe, Shiori; Yamasaki, Masanori; Ebana, Kaworu; Hayashi, Takeshi; Iwata, Hiroyoshi

2016-01-01

Acceleration of genetic improvement of autogamous crops such as wheat and rice is necessary to increase cereal production in response to the global food crisis. Population and pedigree methods of breeding, which are based on inbred line selection, are used commonly in the genetic improvement of autogamous crops. These methods, however, produce a few novel combinations of genes in a breeding population. Recurrent selection promotes recombination among genes and produces novel combinations of genes in a breeding population, but it requires inaccurate single-plant evaluation for selection. Genomic selection (GS), which can predict genetic potential of individuals based on their marker genotype, might have high reliability of single-plant evaluation and might be effective in recurrent selection. To evaluate the efficiency of recurrent selection with GS, we conducted simulations using real marker genotype data of rice cultivars. Additionally, we introduced the concept of an "island model" inspired by evolutionary algorithms that might be useful to maintain genetic variation through the breeding process. We conducted GS simulations using real marker genotype data of rice cultivars to evaluate the efficiency of recurrent selection and the island model in an autogamous species. Results demonstrated the importance of producing novel combinations of genes through recurrent selection. An initial population derived from admixture of multiple bi-parental crosses showed larger genetic gains than a population derived from a single bi-parental cross in whole cycles, suggesting the importance of genetic variation in an initial population. The island-model GS better maintained genetic improvement in later generations than the other GS methods, suggesting that the island-model GS can utilize genetic variation in breeding and can retain alleles with small effects in the breeding population. The island-model GS will become a new breeding method that enhances the potential of genomic selection in autogamous crops, especially bringing long-term improvement.

Island-Model Genomic Selection for Long-Term Genetic Improvement of Autogamous Crops

PubMed Central

Yabe, Shiori; Yamasaki, Masanori; Ebana, Kaworu; Hayashi, Takeshi; Iwata, Hiroyoshi

2016-01-01

Acceleration of genetic improvement of autogamous crops such as wheat and rice is necessary to increase cereal production in response to the global food crisis. Population and pedigree methods of breeding, which are based on inbred line selection, are used commonly in the genetic improvement of autogamous crops. These methods, however, produce a few novel combinations of genes in a breeding population. Recurrent selection promotes recombination among genes and produces novel combinations of genes in a breeding population, but it requires inaccurate single-plant evaluation for selection. Genomic selection (GS), which can predict genetic potential of individuals based on their marker genotype, might have high reliability of single-plant evaluation and might be effective in recurrent selection. To evaluate the efficiency of recurrent selection with GS, we conducted simulations using real marker genotype data of rice cultivars. Additionally, we introduced the concept of an “island model” inspired by evolutionary algorithms that might be useful to maintain genetic variation through the breeding process. We conducted GS simulations using real marker genotype data of rice cultivars to evaluate the efficiency of recurrent selection and the island model in an autogamous species. Results demonstrated the importance of producing novel combinations of genes through recurrent selection. An initial population derived from admixture of multiple bi-parental crosses showed larger genetic gains than a population derived from a single bi-parental cross in whole cycles, suggesting the importance of genetic variation in an initial population. The island-model GS better maintained genetic improvement in later generations than the other GS methods, suggesting that the island-model GS can utilize genetic variation in breeding and can retain alleles with small effects in the breeding population. The island-model GS will become a new breeding method that enhances the potential of genomic selection in autogamous crops, especially bringing long-term improvement. PMID:27115872

Serum androgen levels in women who have recurrent miscarriages and their correlation with markers of endometrial function.

PubMed

Okon, M A; Laird, S M; Tuckerman, E M; Li, T C

1998-04-01

To compare plasma androgen concentrations in women who have recurrent miscarriages and in fertile women, and to correlate the results with concentrations of the endometrial protein PP14 in uterine flushings and plasma from women who have recurrent miscarriages. Retrospective study. Hospital research unit. Women attending a recurrent miscarriage clinic and normal fertile volunteers. Ten of the women with recurrent miscarriages had polycystic ovary disease (PCOD) as assessed by ultrasonography or increased follicular LH levels. Plasma samples were obtained from the women on days LH-7, LH-4, LH+0, and LH+7 or LH+10 of a cycle. An endometrial flushing sample and a biopsy specimen were taken from women with recurrent miscarriages on day LH+7 or LH+10. Androstenedione, testosterone, and sex hormone-binding globulin (SHBG) were measured in the plasma samples. The endometrial protein PP14 was measured in the uterine flushings and in the LH+7 or LH+10 plasma samples from the women with recurrent miscarriages. Testosterone concentrations were higher in the women with recurrent miscarriages both with and without PCOD on days LH-7 and LH-4 of the cycle. Concentrations of androstenedione also were higher in the women with recurrent miscarriages, but without PCOD on day LH-7. Testosterone SHBG ratios were higher in the women with recurrent miscarriages, without PCOD compared with the controls on days LH-7, LH+0, and LH+7. Mean follicular testosterone concentrations were correlated negatively with both uterine (r = -0.47) and plasma (r = -0.49) PP14 levels on day LH+10. Mean luteal phase testosterone SHBG ratios were correlated negatively with uterine PP14 concentrations on day LH+7 of the cycle (r = -0.674). Androgen levels are higher in women who have recurrent miscarriages than in normal fertile controls. These high levels of androgens may have a detrimental effect on endometrial function.

The Timing of the Cognitive Cycle

PubMed Central

Madl, Tamas; Baars, Bernard J.; Franklin, Stan

2011-01-01

We propose that human cognition consists of cascading cycles of recurring brain events. Each cognitive cycle senses the current situation, interprets it with reference to ongoing goals, and then selects an internal or external action in response. While most aspects of the cognitive cycle are unconscious, each cycle also yields a momentary “ignition” of conscious broadcasting. Neuroscientists have independently proposed ideas similar to the cognitive cycle, the fundamental hypothesis of the LIDA model of cognition. High-level cognition, such as deliberation, planning, etc., is typically enabled by multiple cognitive cycles. In this paper we describe a timing model LIDA's cognitive cycle. Based on empirical and simulation data we propose that an initial phase of perception (stimulus recognition) occurs 80–100 ms from stimulus onset under optimal conditions. It is followed by a conscious episode (broadcast) 200–280 ms after stimulus onset, and an action selection phase 60–110 ms from the start of the conscious phase. One cognitive cycle would therefore take 260–390 ms. The LIDA timing model is consistent with brain evidence indicating a fundamental role for a theta-gamma wave, spreading forward from sensory cortices to rostral corticothalamic regions. This posteriofrontal theta-gamma wave may be experienced as a conscious perceptual event starting at 200–280 ms post stimulus. The action selection component of the cycle is proposed to involve frontal, striatal and cerebellar regions. Thus the cycle is inherently recurrent, as the anatomy of the thalamocortical system suggests. The LIDA model fits a large body of cognitive and neuroscientific evidence. Finally, we describe two LIDA-based software agents: the LIDA Reaction Time agent that simulates human performance in a simple reaction time task, and the LIDA Allport agent which models phenomenal simultaneity within timeframes comparable to human subjects. While there are many models of reaction time performance, these results fall naturally out of a biologically and computationally plausible cognitive architecture. PMID:21541015

Dynamical analysis and simulation of a 2-dimensional disease model with convex incidence

NASA Astrophysics Data System (ADS)

Yu, Pei; Zhang, Wenjing; Wahl, Lindi M.

2016-08-01

In this paper, a previously developed 2-dimensional disease model is studied, which can be used for both epidemiologic modeling and in-host disease modeling. The main attention of this paper is focused on various dynamical behaviors of the system, including Hopf and generalized Hopf bifurcations which yield bistability and tristability, Bogdanov-Takens bifurcation, and homoclinic bifurcation. It is shown that the Bogdanov-Takens bifurcation and homoclinic bifurcation provide a new mechanism for generating disease recurrence, that is, cycles of remission and relapse such as the viral blips observed in HIV infection.

Dense Ocean Floor Network for Earthquakes and Tsunamis; DONET/ DONET2, Part2 -Development and data application for the mega thrust earthquakes around the Nankai trough-

NASA Astrophysics Data System (ADS)

Kaneda, Y.; Kawaguchi, K.; Araki, E.; Matsumoto, H.; Nakamura, T.; Nakano, M.; Kamiya, S.; Ariyoshi, K.; Baba, T.; Ohori, M.; Hori, T.; Takahashi, N.; Kaneko, S.; Donet Research; Development Group

2010-12-01

Yoshiyuki Kaneda Katsuyoshi Kawaguchi*, Eiichiro Araki*, Shou Kaneko*, Hiroyuki Matsumoto*, Takeshi Nakamura*, Masaru Nakano*, Shinichirou Kamiya*, Keisuke Ariyoshi*, Toshitaka Baba*, Michihiro Ohori*, Narumi Takakahashi*, and Takane Hori** * Earthquake and Tsunami Research Project for Disaster Prevention, Leading Project , Japan Agency for Marine-Earth Science and Technology (JAMSTEC) **Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) DONET (Dense Ocean Floor Network for Earthquakes and Tsunamis) is the real time monitoring system of the Tonankai seismogenic zones around the Nankai trough southwestern Japan. We were starting to develop DONET to perform real time monitoring of crustal activities over there and the advanced early warning system. DONET will provide important and useful data to understand the Nankai trough maga thrust earthquake seismogenic zones and to improve the accuracy of the earthquake recurrence cycle simulation. Details of DONET concept are as follows. 1) Redundancy, Extendable function and advanced maintenance system using the looped cable system, junction boxes and the ROV/AUV. DONET has 20 observatories and incorporated in a double land stations concept. Also, we are developed ROV for the 10km cable extensions and heavy weight operations. 2) Multi kinds of sensors to observe broad band phenomena such as long period tremors, very low frequency earthquakes and strong motions of mega thrust earthquakes over M8: Therefore, sensors such as a broadband seismometer, an accelerometer, a hydrophone, a precise pressure gauge, a differential pressure gauge and a thermometer are equipped with each observatory in DONET. 3) For speedy detections, evaluations and notifications of earthquakes and tsunamis: DONET system will be deployed around the Tonankai seismogenic zone. 4) Provide data of ocean floor crustal deformations derived from pressure sensors: Simultaneously, the development of data assimilation method using DONET data is very important to improve the recurrence cycle simulation model. 5) Understanding of the interaction between the crust and upper mantle around the Nankai trough subduction zone. We will deploy DONET not only in the Tonankai seismogenic zone but also DONET2 with high voltages in the Nankai seismogenic zone western the Nankai trough: The total system will be deployed to understand the seismic linkage between the Tonankai and Nankai earthquakes: Using DONET and DONET2 data, we will be able to observe the crustal activities and before and after slips at the Tonankai earthquake and Nankai earthquake. And we will improve the recurrence cycle simulation model by the advanced data assimilation method. Actually, we constructed one observatory in DONET and observed some earthquakes and tsunamis. We will introduce details of DONET/DONET2 and some observed data.

Factors affecting the outcome of "endometrial scratch" in women with recurrent implantation failure.

PubMed

Coughlan, Carol; Yuan, Xi; Demirol, Aygul; Ledger, William; Li, Tin Chiu

2014-01-01

To examine factors affecting the outcome of the endometrial scratch in women with recurrent implantation failure. A total of 57 eligible patients with a history of recurrent implantation failure underwent an endometrial biopsy in the luteal phase of the menstrual cycle in the month immediately preceding the embryo transfer cycle. The comparative group consisted of a retrospective cohort of 66 women with recurrent implantation failure but without endometrial biopsy. There were no significant differences between the intervention and control groups in terms of age, follicle-stimulating hormone (FSH), free androgen index, anti-Müllerian hormone, body mass index, the number of embryos transferred, and the number of embryo transfer cycles. The clinical pregnancy rate in the intervention group (53%) was significantly (p < 0.001) higher than that of the control group (15%). The only predictive factor was FSH. Women with FSH < or =10 IU/L had a pregnancy rate of 57.8%, significantly (p < 0.05) higher than that (20%) of women with FSH >10 IU/L. Women with a normal FSH are more likely to derive benefit from endometrial scratch.

Responses of the lower thermospheric temperature to the 9 day and 13.5 day oscillations of recurrent geomagnetic activity

NASA Astrophysics Data System (ADS)

Jiang, Guoying; Wang, Wenbin; Xu, Jiyao; Yue, Jia; Burns, Alan G.; Lei, Jiuhou; Mlynczak, Martin G.; Rusell, James M., III

2015-04-01

Responses of the lower thermospheric temperature to the 9 day and 13.5 day oscillations of recurrent geomagnetic activity and solar EUV radiation have been investigated using neutral temperature data observed by the TIMED/SABER (Thermosphere IonosphereMesosphere Energetics and Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry) instrument and numerical experiments by the NCAR-TIME-GCM (National Center for Atmospheric Research-thermosphere-ionosphere-mesosphere electrodynamics-general circulation model). The TIMED/SABER data analyzed were for the period from 2002 to 2007 during the declining phase of solar cycle 23. The observations show that the zonal mean temperature in the lower thermosphere oscillated with periods of near 9 and 13.5 days in the height range of 100-120 km. These oscillations were more strongly correlated with the recurrent geomagnetic activity than with the solar EUV variability of the same periods. The 9 day and 13.5 day oscillations of lower thermospheric temperature had greater amplitudes at high latitudes than at low latitudes; they also had larger amplitudes at higher altitudes, and the oscillations could penetrate down to ~105 km, depending on the strength of the recurrent geomagnetic activity for a particular time period. The data further show that the periodic responses of the lower thermospheric temperature to recurrent geomagnetic activity were different in the two hemispheres. In addition, numerical experiments have been carried out using the NCAR-TIME-GCM to investigate the causal relationship between the temperature oscillations and the geomagnetic activity and solar EUV variations of the same periods. Model simulations showed the same periodic oscillations as those seen in the observations when the real geomagnetic activity index, Kp, was used to drive the model. These numerical results show that recurrent geomagnetic activity is the main cause of the 9 day and 13.5 day variations in the lower thermosphere temperature, and the contribution from solar EUV variations is minor. Furthermore, we also found that consecutive coronal mass ejection events could cause long-duration enhancements in the lower thermospheric temperature that strengthen the 9 day and 13.5 day signals, and this kind of phenomenon mostly occurred between 2002 and 2005 during the declining phase of solar cycle 23.

Responses of the lower thermospheric temperature to the 9 day and 13.5 day oscillations of recurrent geomagnetic activity

NASA Astrophysics Data System (ADS)

Jiang, Guoying; Wang, Wenbin; Xu, Jiyao; Yue, Jia; Burns, Alan G.; Lei, Jiuhou; Mlynczak, Martin G.; Rusell, James M.

2014-06-01

Responses of the lower thermospheric temperature to the 9 day and 13.5 day oscillations of recurrent geomagnetic activity and solar EUV radiation have been investigated using neutral temperature data observed by the TIMED/SABER (Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Sounding of the Atmosphere using Broadband Emission Radiometry) instrument and numerical experiments by the NCAR-TIME-GCM (National Center for Atmospheric Research-thermosphere-ionosphere-mesosphere electrodynamics-general circulation model). The TIMED/SABER data analyzed were for the period from 2002 to 2007 during the declining phase of solar cycle 23. The observations show that the zonal mean temperature in the lower thermosphere oscillated with periods of near 9 and 13.5 days in the height range of 100-120 km. These oscillations were more strongly correlated with the recurrent geomagnetic activity than with the solar EUV variability of the same periods. The 9 day and 13.5 day oscillations of lower thermospheric temperature had greater amplitudes at high latitudes than at low latitudes; they also had larger amplitudes at higher altitudes, and the oscillations could penetrate down to 105 km, depending on the strength of the recurrent geomagnetic activity for a particular time period. The data further show that the periodic responses of the lower thermospheric temperature to recurrent geomagnetic activity were different in the two hemispheres. In addition, numerical experiments have been carried out using the NCAR-TIME-GCM to investigate the causal relationship between the temperature oscillations and the geomagnetic activity and solar EUV variations of the same periods. Model simulations showed the same periodic oscillations as those seen in the observations when the real geomagnetic activity index, Kp, was used to drive the model. These numerical results show that recurrent geomagnetic activity is the main cause of the 9 day and 13.5 day variations in the lower thermosphere temperature, and the contribution from solar EUV variations is minor. Furthermore, we also found that consecutive coronal mass ejection events could cause long-duration enhancements in the lower thermospheric temperature that strengthen the 9 day and 13.5 day signals, and this kind of phenomenon mostly occurred between 2002 and 2005 during the declining phase of solar cycle 23.

Testcross Response to Four Cycles of Half-sib and S2 Recurrent Selection in the BS13 Maize (Zea mays L.) Population

USDA-ARS?s Scientific Manuscript database

Inbred progeny recurrent selection was shown to be superior to several forms of outbred-progeny recurrent selection for improving population per se performance based on theoretical arguments. However, recent improvements to theory and mounting empirical evidence suggest that inbred-progeny recurren...

Genetic progress in the UNB-2U population of popcorn under recurrent selection in Rio de Janeiro, Brazil.

PubMed

Ribeiro, R M; do Amaral Júnior, A T; Gonçalves, L S A; Candido, L S; Silva, T R C; Pena, G F

2012-05-15

As part of the Universidade Estadual do Norte Fluminense recurrent selection program of popcorn, we evaluated full-sib families of the sixth cycle of recurrent selection and estimated genetic progress for grain yield and expansion capacity. We assessed 200 full-sib families for 10 agronomic traits, in a randomized block design, with two replications within sets in two environments: Campos dos Goytacazes and Itaocara, in the State of Rio de Janeiro, Brazil. There were significant differences for families/"sets" for all traits, indicating genetic variability that could be exploited in future cycles. In the selection of superior progenies, the Mulamba and Mock index gave the best gains for popping expansion (PE) and grain yield (GY), with values of 10.97 and 15.30%, respectively, using random economic weights. By comparing the evolution of the means obtained for PE and GY in the cycles C(0), C(1), C(2), C(3), C(4), C(5), and predicted for C(6), a steady increase was observed for both PE and GY, with the addition of 1.71 mL/g (R(2) = 0.93) and 192.87 kg/ha (R(2) = 0.88), respectively, in each cycle. Given the good performance of this popcorn population in successive cycles of intrapopulation recurrent selection, we expect that a productive variety with high expansion capacity will soon be available for producers in the north and northwest regions of Rio de Janeiro State, Brazil.

Complex Synchronization Phenomena in Ecological Systems

NASA Astrophysics Data System (ADS)

Stone, Lewi; Olinky, Ronen; Blasius, Bernd; Huppert, Amit; Cazelles, Bernard

2002-07-01

Ecological and biological systems provide us with many striking examples of synchronization phenomena. Here we discuss a number of intriguing cases and attempt to explain them taking advantage of a modelling framework. One main focus will concern synchronized ecological end epidemiological cycles which have Uniform Phase growth associated with their regular recurrence, and Chaotic Amplitudes - a feature we term UPCA. Examples come from different areas and include decadal cycles of small mammals, recurrent viral epidemics such as childhood infections (eg., measles), and seasonally driven phytoplankton blooms observed in lakes and the oceans. A more detailed theoretical analysis of seasonally synchronized chaotic population cycles is presented.

Applying the recurrence quantification analysis method for analyzing the recurrence of simulated multiple African easterly waves in 2006

NASA Astrophysics Data System (ADS)

Reyes, T.; Shen, B. W.; Wu, Y.; Faghih-Naini, S.; Li, J.

2017-12-01

In late August, 2006, six African easterly waves (AEWs) appeared sequentially over the African continent during a 30-day period. With a global model of 1/4 degree resolution, statistics of these AEWs were realistically captured. More interestingly, the formation, subsequent intensification, and movement of Hurricane Helene (2006) were simulated to a degree of satisfaction during the model integration from Day 22 to 30 (Shen et al., 2010). We then developed a parallel ensemble empirical mode decomposition method (PEEMD; Shen et al. 2012; 2017; Cheung et al. 2013) to reveal the role of downscaling processes associated with the environmental flows in determining the timing and location of Helene's formation (Wu and Shen, 2016), supporting its practical predictability at extended-range time scales. Recently, further analysis of the correlation coefficients (CCs) between the simulated temperature and reanalysis data showed that CCs are above 0.65 during the 30 day simulations but display oscillations. While high CCs are consistent with the accurate simulations of the AEWs and Hurricane Helene, oscillations may indicate the inaccurate simulations of moving speeds (i.e., an inaccurate phase) as compared to observations. The observed AEWs have comparable but slightly different periods. To quantitatively examine this space-varying feature in observations and the temporal oscillations in the CCs of the simulations, we select recurrence quantification analysis (RQA) methods and the recurrence plot (RP) in order to account for the local nature of these features. A recurrence is defined when the trajectory returns back to the neighborhood of a previously visited state. With the RQA methods, we can compute the "recurrence rate" and "determinism" present in the RP in order to reveal the degree of recurrence and determinism (or "predictability") of the recurrent solutions. To verify of our implementations in Python, we applied our methods to analyze idealized solutions (e.g., quasi-periodic solutions and limit torus) from the three-dimensional and five-dimensional dissipative or non-dissipative Lorenz Models (Shen and Faghih-Naini, 2017). Post verification, we apply the RQA methods to analyze the 30-days reanalysis and simulation data. In this talk, we will present preliminary but promising results.

Omitting elective nodal irradiation during thoracic irradiation in limited-stage small cell lung cancer--evidence from a phase II trial.

PubMed

Colaco, Rovel; Sheikh, Hamid; Lorigan, Paul; Blackhall, Fiona; Hulse, Paul; Califano, Raffaele; Ashcroft, Linda; Taylor, Paul; Thatcher, Nicholas; Faivre-Finn, Corinne

2012-04-01

Omitting elective nodal irradiation (ENI) in limited-stage disease small cell lung cancer (LD-SCLC) is expected to result in smaller radiation fields. We report on data from a randomised phase II trial that omitted ENI in patients receiving concurrent chemo-radiotherapy for LD-SCLC. 38 patients with LD-SCLC were randomised to receive once-daily (66 Gy in 33 fractions) or twice-daily (45 Gy in 30 fractions) radiotherapy (RT). 3D-conformal RT was given concurrently with cisplatin and etoposide starting with the second cycle of a total of four cycles. The gross tumour volume was defined as primary tumour with involved lymph nodes (nodes ≥1 cm in short axis) identifiable with CT imaging. ENI was not used. Six recurrence patterns were identified: recurrence within planning target volume (PTV) only, recurrence within PTV+regional nodal recurrence and/or distant recurrence, isolated nodal recurrence outside PTV, nodal recurrence outside PTV+distant recurrence, distant metastases only and no recurrence. At median follow-up 16.9 months, 31/38 patients were evaluable and 14/31 patients had relapsed. There were no isolated nodal recurrences. Eight patients relapsed with intra-thoracic disease: 2 within PTV only, 4 within PTV and distantly and 2 with nodal recurrence outside PTV plus distant metastases. Rates of grade 3+ acute oesophagitis and pneumonitis in the 31 evaluable patients were 23 and 3% respectively. In our study of LD-SCLC, omitting ENI based on CT imaging was not associated with a high risk of isolated nodal recurrence, although further prospective studies are needed to confirm this. Routine ENI omission will be further evaluated prospectively in the ongoing phase III CONVERT trial (NCT00433563). Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Tsunamis generated by eruptions from mount st. Augustine volcano, alaska.

PubMed

Kienle, J; Kowalik, Z; Murty, T S

1987-06-12

During an eruption of the Alaskan volcano Mount St. Augustine in the spring of 1986, there was concern about the possibility that a tsunami might be generated by the collapse of a portion of the volcano into the shallow water of Cook Inlet. A similar edifice collapse of the volcano and ensuing sea wave occurred during an eruption in 1883. Other sea waves resulting in great loss of life and property have been generated by the eruption of coastal volcanos around the world. Although Mount St. Augustine remained intact during this eruptive cycle, a possible recurrence of the 1883 events spurred a numerical simulation of the 1883 sea wave. This simulation, which yielded a forecast of potential wave heights and travel times, was based on a method that could be applied generally to other coastal volcanos.

Phase 2 trial of BCNU plus irinotecan in adults with malignant glioma1

PubMed Central

Reardon, David A.; Quinn, Jennifer A.; Rich, Jeremy N.; Gururangan, Sridharan; Vredenburgh, James; Sampson, John H.; Provenzale, James M.; Walker, Amy; Badruddoja, Michael; Tourt-Uhlig, Sandra; Herndon, James E.; Dowell, Jeannette M.; Affronti, Mary Lou; Jackson, Susanne; Allen, Deborah; Ziegler, Karen; Silverman, Steven; Bohlin, Cindy; Friedman, Allan H.; Bigner, Darell D.; Friedman, Henry S.

2004-01-01

In preclinical studies, BCNU, or 1,3-bis(2-chloroethyl)-1-nitrosourea, plus CPT-11 (irinotecan) exhibits schedule-dependent, synergistic activity against malignant glioma (MG). We previously established the maximum tolerated dose of CPT-11 when administered for 4 consecutive weeks in combination with BCNU administered on the first day of each 6-week cycle. We now report a phase 2 trial of BCNU plus CPT-11 for patients with MG. In the current study, BCNU (100 mg/m2) was administered on day 1 of each 6-week cycle. CPT-11 was administered on days 1, 8, 15, and 22 at 225 mg/m2 for patients receiving CYP3A1- or CYP3A4-inducing anticonvulsants and at 125 mg/m2 for those not on these medications. Newly diagnosed patients received up to 3 cycles before radiotherapy, while recurrent patients received up to 8 cycles. The primary end point of this study was radiographic response, while time to progression and overall survival were also assessed. Seventy-six patients were treated, including 37 with newly diagnosed tumors and 39 with recurrent disease. Fifty-six had glioblastoma multiforme, 18 had anaplastic astrocytoma, and 2 had anaplastic oligodendroglioma. Toxicities (grade ⩾3) included infections (13%), thromboses (12%), diarrhea (10%), and neutropenia (7%). Interstitial pneumonitis developed in 4 patients. Five newly diagnosed patients (14%; 95% CI, 5%–29%) achieved a radiographic response (1 complete response and 4 partial responses). Five patients with recurrent MG also achieved a response (1 complete response and 4 partial responses; 13%; 95% CI, 4%–27%). More than 40% of both newly diagnosed and recurrent patients achieved stable disease. Median time to progression was 11.3 weeks for recurrent glioblastoma multiforme patients and 16.9 weeks for recurrent anaplastic astrocytoma/anaplastic oligodendroglioma patients. We conclude that the activity of BCNU plus CPT-11 for patients with MG appears comparable to that of CPT-11 alone and may be more toxic. PMID:15134628

Electrogram Morphology Recurrence Patterns during Atrial Fibrillation

PubMed Central

Ng, Jason; Gordon, David; Passman, Rod S.; Knight, Bradley P.; Arora, Rishi; Goldberger, Jeffrey J.

2014-01-01

Background Traditional mapping of atrial fibrillation (AF) is limited by changing electrogram morphologies and variable cycle lengths. Objective We tested the hypothesis that morphology recurrence plot analysis would identify sites of stable and repeatable electrogram morphology patterns. Methods AF electrograms recorded from left atrial (LA) and right atrial (RA) sites in 19 patients (10 male, 59±10 years old) prior to AF ablation were analyzed. Morphology recurrence plots for each electrogram recording were created by cross-correlation of each automatically detected activation with every other activation in the recording. A recurrence percentage, the percentage of the most common morphology, and the mean cycle length of activations with the most common morphology (CLR) were computed. Results The morphology recurrence plots commonly showed checkerboard patterns of alternating high and low cross correlation values indicating periodic recurrences in morphologies. The mean recurrence percentage for all sites and all patients was 38±25%. The highest recurrence percentage per patient averaged 83±17%. The highest recurrence percentage was located in the RA in 5 patients and in the LA in 14 patients. Patients with sites of shortest CLR in the LA and RA had ablation failure rates of 25% and 100%, respectively (HR=4.95; p=0.05). Conclusions A new technique to characterize electrogram morphology recurrence demonstrated that there is a distribution of sites with high and low repeatability of electrogram morphologies. Sites with rapid activation of highly repetitive morphology patterns may be critical to sustaining AF. Further testing of this approach to map and ablate AF sources is warranted. PMID:25101485

Earthquake Clustering on Normal Faults: Insight from Rate-and-State Friction Models

NASA Astrophysics Data System (ADS)

Biemiller, J.; Lavier, L. L.; Wallace, L.

2016-12-01

Temporal variations in slip rate on normal faults have been recognized in Hawaii and the Basin and Range. The recurrence intervals of these slip transients range from 2 years on the flanks of Kilauea, Hawaii to 10 kyr timescale earthquake clustering on the Wasatch Fault in the eastern Basin and Range. In addition to these longer recurrence transients in the Basin and Range, recent GPS results there also suggest elevated deformation rate events with recurrence intervals of 2-4 years. These observations suggest that some active normal fault systems are dominated by slip behaviors that fall between the end-members of steady aseismic creep and periodic, purely elastic, seismic-cycle deformation. Recent studies propose that 200 year to 50 kyr timescale supercycles may control the magnitude, timing, and frequency of seismic-cycle earthquakes in subduction zones, where aseismic slip transients are known to play an important role in total deformation. Seismic cycle deformation of normal faults may be similarly influenced by its timing within long-period supercycles. We present numerical models (based on rate-and-state friction) of normal faults such as the Wasatch Fault showing that realistic rate-and-state parameter distributions along an extensional fault zone can give rise to earthquake clusters separated by 500 yr - 5 kyr periods of aseismic slip transients on some portions of the fault. The recurrence intervals of events within each earthquake cluster range from 200 to 400 years. Our results support the importance of stress and strain history as controls on a normal fault's present and future slip behavior and on the characteristics of its current seismic cycle. These models suggest that long- to medium-term fault slip history may influence the temporal distribution, recurrence interval, and earthquake magnitudes for a given normal fault segment.

MicroRNA-93 inhibits tumor growth and early relapse of human colorectal cancer by affecting genes involved in the cell cycle.

PubMed

Yang, I-Ping; Tsai, Hsiang-Lin; Hou, Ming-Feng; Chen, Ku-Chung; Tsai, Pei-Chien; Huang, Szu-Wei; Chou, Wen-Wen; Wang, Jaw-Yuan; Juo, Suh-Hang Hank

2012-08-01

Colorectal cancer (CRC) is associated with high recurrence and mortality. Because deregulation of microRNAs is associated with CRC development and recurrence, the expression levels of microRNAs can be a simple and reliable biomarker to detect postoperative early relapse, thereby helping physicians to treat high-risk patients more efficiently. We used microRNA arrays and observed that microRNA-93 had substantially different expression levels in early (recurrence within 12 months after surgery) and non-early relapse CRC patients. The replication study, which included 35 early relapse and 42 non-early relapse subjects, further confirmed overexpression of microRNA-93 in non-early relapse samples. The in vitro and in vivo effects of microRNA-93 were investigated by examining cell proliferation, migration and invasion, as well as cell cycles, target-gene expression and xenograft in null mice. Cellular studies showed that the overexpression of microRNA-93 inhibited colon cancer cell proliferation and migration but not invasion. The cell cycle studies also revealed that microRNA-93 caused an accumulation of the G2 population. However, microRNA-93 could not induce cell apoptosis or necrosis. Functional studies showed that microRNA-93 could suppress CCNB1 protein expression leading to cell cycle arrest in the G2 phase. Moreover, microRNA-93 repressed expression of ERBB2, p21 and VEGF, all of which are involved in cell proliferation. MicroRNA-93 also suppressed tumor growth in null mice. This study showed that microRNA-93 can inhibit tumorigenesis and reduce the recurrence of CRC; these findings may have potential clinical applications for predicting the recurrence of CRC.

Biologic determinants of tumor recurrence in stage II colon cancer: validation study of the 12-gene recurrence score in cancer and leukemia group B (CALGB) 9581.

PubMed

Venook, Alan P; Niedzwiecki, Donna; Lopatin, Margarita; Ye, Xing; Lee, Mark; Friedman, Paula N; Frankel, Wendy; Clark-Langone, Kim; Millward, Carl; Shak, Steven; Goldberg, Richard M; Mahmoud, Najjia N; Warren, Robert S; Schilsky, Richard L; Bertagnolli, Monica M

2013-05-10

A greater understanding of the biology of tumor recurrence should improve adjuvant treatment decision making. We conducted a validation study of the 12-gene recurrence score (RS), a quantitative assay integrating stromal response and cell cycle gene expression, in tumor specimens from patients enrolled onto Cancer and Leukemia Group B (CALGB) 9581. CALGB 9581 randomly assigned 1,713 patients with stage II colon cancer to treatment with edrecolomab or observation and found no survival difference. The analysis reported here included all patients with available tissue and recurrence (n = 162) and a random (approximately 1:3) selection of nonrecurring patients. RS was assessed in 690 formalin-fixed paraffin-embedded tumor samples with quantitative reverse transcriptase polymerase chain reaction by using prespecified genes and a previously validated algorithm. Association of RS and recurrence was analyzed by weighted Cox proportional hazards regression. Continuous RS was significantly associated with risk of recurrence (P = .013) as was mismatch repair (MMR) gene deficiency (P = .044). In multivariate analyses, RS was the strongest predictor of recurrence (P = .004), independent of T stage, MMR, number of nodes examined, grade, and lymphovascular invasion. In T3 MMR-intact (MMR-I) patients, prespecified low and high RS groups had average 5-year recurrence risks of 13% (95% CI, 10% to 16%) and 21% (95% CI, 16% to 26%), respectively. The 12-gene RS predicts recurrence in stage II colon cancer in CALGB 9581. This is consistent with the importance of stromal response and cell cycle gene expression in colon tumor recurrence. RS appears to be most discerning for patients with T3 MMR-I tumors, although markers such as grade and lymphovascular invasion did not add value in this subset of patients.

Which is worse? Comparison of ART outcome between women with primary or recurrent endometriomas.

PubMed

Ata, Baris; Mumusoglu, Sezcan; Aslan, Kiper; Seyhan, Ayse; Kasapoglu, Isil; Avci, Berrin; Urman, Bulent; Bozdag, Gurkan; Uncu, Gurkan

2017-07-01

Are live birth rates (LBR) different after ART cycles between women with primary or recurrent endometrioma? Women with recurrent endometrioma have similar LBR as compared to patients with primary endometrioma. Recurrence rate can be as high as 29% after endometrioma excision. Prior studies on management of endometrioma before ART involve primary endometriomas. There is limited information regarding the prognosis of women with recurrent endometriomas. A multicenter retrospective cohort study, including 76 women with primary and 82 women with recurrent endometriomas treated at the participating centers over a 6-year period. Women with endometrioma who underwent ART at three academic ART centers. Couples with another indication for ART were excluded. Female age, median number of prior failed ART cycles, proportion of patients with bilateral endometrioma (28 versus 28.9%), ovarian stimulation protocols, and total gonadotropin consumption were similar between the study groups. Numbers of metaphase two oocytes (5 versus 6), number of embryos transferred, and the proportion of patients undergoing blastocyst transfer were similar across the study groups. Clinical pregnancy rates (36.6 versus 34.2%, absolute difference 2.4%, 95% CI: -12.5 to 17.3%, P = 0.83) and LBR (35.4 versus 30.3%, absolute difference 5.1%, 95% CI: -9.5 to 19.7%, P = 0.51) per started cycle in recurrent and primary endometrioma were similar. Comparable success rates were also confirmed with logistic regression analysis (OR: 1.14, 95% CI: 0.78-0.57, P = 2.3). The retrospective design has inherent limitations. Some women with severely decreased ovarian reserve after primary endometrioma excision may not have pursued further treatment. The management of endometrioma prior to ART is controversial but a different management strategy is not required for recurrent endometriomas. Since recurrent endometriomas do not have a worse impact on ART outcome than primary endometriomas, and repeat surgery has a higher risk for complications, conservative management without surgery can be justified. No funding or competing interests to declare. None. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Tailored central nervous system-directed treatment strategy for isolated CNS recurrence of adult acute myeloid leukemia.

PubMed

Zheng, Changcheng; Liu, Xin; Zhu, Weibo; Cai, Xiaoyan; Wu, Jingsheng; Sun, Zimin

2014-06-01

The aim of this report was to investigate the tailored treatment strategies for isolated central nervous system (CNS) recurrence in adult patients with acute myeloid leukemia (AML). Isolated CNS recurrence was documented in 34 patients: there were 18, 6, and 10 patients with meningeal involvement type (type A), cranial nerve palsy type (type B), and myeloid sarcoma type (type C), respectively. For patients with type A, intrathecal chemotherapy was the predominant strategy. For type B, systemic HD-Ara-C with four cycles was the main treatment. For type C, cranial irradiation or craniospinal irradiation was adopted and two cycles of HD-Ara-C were given after the irradiation. The 5-year cumulative incidence of CNS recurrence was 12.8%. There was a significantly higher WBC count (32.6∼60.8 × 10(9)/l) in patients at first diagnosis who developed CNS recurrence (all of the three types) compared with patients with no CNS recurrence (10.1 × 10(9)/l) (P = 0.005). We found that a significantly more patients with AML-M5 and 11q23 abnormalities developed CNS recurrence in type A (P < 0.001, 0.005). Twenty-four out of 34 patients (70.6%) with CNS recurrence achieved CNS complete remission at a median of 58 days (range, 30-120). The 3-year disease-free survival and overall survival estimates for all CNS recurrence patients were 21.6 and 25.3%, respectively. This report indicates that the tailored CNS-directed strategy is an effective modality to treat CNS recurrence in adult AML, but further studies are needed to improve the long-term survival.

Usefulness of high-dose intravenous human immunoglobulins treatment for refractory recurrent pericarditis.

PubMed

Moretti, Michele; Buiatti, Alessandra; Merlo, Marco; Massa, Laura; Fabris, Enrico; Pinamonti, Bruno; Sinagra, Gianfranco

2013-11-01

The management of refractory recurrent pericarditis is challenging. Previous clinical reports have noted a beneficial effect of high-dose intravenous human immunoglobulins (IvIgs) in isolated and systemic inflammatory disease-related forms. In this article, we analyzed retrospectively our clinical experience with IvIg therapy in a series of clinical cases of pericarditis refractory to conventional treatment. We retrospectively analyzed 9 patients (1994 to 2010) with refractory recurrent pericarditis, who received high-dose IvIg as a part of their medical treatment. Nonsteroidal anti-inflammatory drugs (NSAIDs), steroids, or colchicine treatment was not discontinued during IvIg treatment. No patients had a history of autoimmune or connective tissue diseases. During an average period of 11 months from the first recurrence, patients had experienced a mean of 5 relapses before the first IvIg treatment. In 4 cases, patients showed complete clinical remission with no further relapse after the first IvIg cycle. Two patients experienced a single minor relapse, responsive to short-term nonsteroidal anti-inflammatory drugs. In 2 patients, we performed a second cycle of IvIg after a recurrence of pericarditis, with subsequent complete remission. One patient did not respond to 3 cycles of IvIg and subsequently underwent pericardial window and long-term immunosuppressive treatment. No major adverse effect was observed in consequence of IvIg administration in all the cases. In conclusion, although IvIg mode of action is still poorly understood in this setting, this treatment can be considered as an option in patients with recurrent pericarditis refractory to conventional medical treatment and, in our small series, has proved to be effective in 8 of 9 cases. Copyright © 2013 Elsevier Inc. All rights reserved.

Detecting transitions in protein dynamics using a recurrence quantification analysis based bootstrap method.

PubMed

Karain, Wael I

2017-11-28

Proteins undergo conformational transitions over different time scales. These transitions are closely intertwined with the protein's function. Numerous standard techniques such as principal component analysis are used to detect these transitions in molecular dynamics simulations. In this work, we add a new method that has the ability to detect transitions in dynamics based on the recurrences in the dynamical system. It combines bootstrapping and recurrence quantification analysis. We start from the assumption that a protein has a "baseline" recurrence structure over a given period of time. Any statistically significant deviation from this recurrence structure, as inferred from complexity measures provided by recurrence quantification analysis, is considered a transition in the dynamics of the protein. We apply this technique to a 132 ns long molecular dynamics simulation of the β-Lactamase Inhibitory Protein BLIP. We are able to detect conformational transitions in the nanosecond range in the recurrence dynamics of the BLIP protein during the simulation. The results compare favorably to those extracted using the principal component analysis technique. The recurrence quantification analysis based bootstrap technique is able to detect transitions between different dynamics states for a protein over different time scales. It is not limited to linear dynamics regimes, and can be generalized to any time scale. It also has the potential to be used to cluster frames in molecular dynamics trajectories according to the nature of their recurrence dynamics. One shortcoming for this method is the need to have large enough time windows to insure good statistical quality for the recurrence complexity measures needed to detect the transitions.

Recurrent selection increases the seed germination of little bluestem (Schizachyrium scoparium)

USDA-ARS?s Scientific Manuscript database

Rainfall is often inadequate for satisfactory seed germination and emergence under field conditions. This research was designed to improve the seed germination of six experimental lines of little bluestem [Schizachyrium scoparium (Michx.) Nash]. Two cycle of recurrent selection were used to develo...

The effects of enhanced hexapod motion on airline pilot recurrent training and evaluation

DOT National Transportation Integrated Search

2003-08-13

A quasi-transfer experiment tested the effect of : simulator motion on recurrent evaluation and training : of airline pilots. Two groups of twenty B747-400 pilots : were randomly assigned to a flight simulator with or : without platform motion. In th...

Safety of multiple repeated cycles of 177Lu-octreotate in patients with recurrent neuroendocrine tumour.

PubMed

Yordanova, Anna; Mayer, Karin; Brossart, Peter; Gonzalez-Carmona, Maria A; Strassburg, Christian P; Essler, Markus; Ahmadzadehfar, Hojjat

2017-07-01

Peptide receptor radionuclide therapy (PRRT) is an effective therapy in patients with a somatostatin receptor-positive neuroendocrine tumour (NET). Still unclear is how many cycles of 177 Lu-octreotate can be repeated while maintaining an acceptable toxicity profile. The purpose of this study was to assess the safety of repeated PRRT in patients with recurrent NET. We retrospectively evaluated data from 15 patients treated with repeated PRRT between 2004 and 2015. The median administered activity was 63.8 GBq (range 52-96.6 GBq) in a median of 9 cycles (range 8-13 cycles). Nonhaematological and haematological toxicities were assessed from clinical reports and laboratory data. The rates of adverse events in three therapy groups were compared: during cycles 1 to 4, cycles 5 to 8, and cycles 9 to 13. Baseline laboratory assessments were also compared with data obtained at the end of treatment. The overall survival in the study patients was compared with survival data in patients who received only a baseline PRRT of three or four cycles. We observed no life-threatening adverse events (CTC-4) during 177 Lu-octreotate treatment. Reversible haematological toxicity (CTC-3) occurred in two patients (13%). No CTC-3/4 nephrotoxicity was recorded. More CTC-3 adverse events were recorded in the first therapy group than in the other two groups. Furthermore, there were no significant changes in the mean values of thrombocytes, leucocytes and serum creatinine before and after therapy. However, the mean haemoglobin levels fell from 14 g/dL to 11 g/dL. Finally, compared with those patients who received three or four cycles, there was a survival benefit in patients treated with repeated PRRT (censored overall survival 85.6 vs. 69.7 months, p < 0.001). Therapy with eight or more cycles of 177 Lu-octreotate was well tolerated and led to a survival benefit in patients with recurrent NET.

Clinical Significance and Characteristic Clinical Differences of Cytolytic Vaginosis in Recurrent Vulvovaginitis.

PubMed

Yang, Shuhua; Zhang, Yuexiang; Liu, Ying; Wang, Jianhong; Chen, Shuqin; Li, Shuxia

2017-01-01

The study aimed to evaluate whether cytolytic vaginosis (CV) has important clinical implications for recurrent vulvovaginitis and to identify clinical differences between CV and vulvovaginal candidosis (VVC). Medical histories, physical examinations and laboratory findings were used to diagnose and assess the prevalence rates of various vulvovaginal infections among 536 women with recurrent vulvovaginitis. Chi-square and Fisher exact tests were used to compare age, menstrual cycle phase at episode onset, symptoms/signs of infection and discharge characteristics between CV and VVC with single infection. Among the 484 women with a single-infection recurrent vulvovaginitis, the prevalence of CV (n = 143; 26.7%) was second only to VVC (n = 196; 36.6%). CV symptoms occurred predominantly during the ovulatory and luteal phases. Meanwhile, VVC episodes were not concentrated premenstrually, but rather occurred throughout the menstrual cycle. Significant differences were found in the vaginal pH, discharge characteristics and frequency of inflammatory symptoms between the 2 groups. CV is clinically important, because it is a common cause of recurrent vulvovaginitis. To distinguish CV from VVC, gynecologists should consider the patient's medical history, physical and laboratory findings, vaginal pH and vaginal discharge characteristics. © 2016 S. Karger AG, Basel.

Dynamics of folding: Impact of fault bend folds on earthquake cycles

NASA Astrophysics Data System (ADS)

Sathiakumar, S.; Barbot, S.; Hubbard, J.

2017-12-01

Earthquakes in subduction zones and subaerial convergent margins are some of the largest in the world. So far, forecasts of future earthquakes have primarily relied on assessing past earthquakes to look for seismic gaps and slip deficits. However, the roles of fault geometry and off-fault plasticity are typically overlooked. We use structural geology (fault-bend folding theory) to inform fault modeling in order to better understand how deformation is accommodated on the geological time scale and through the earthquake cycle. Fault bends in megathrusts, like those proposed for the Nepal Himalaya, will induce folding of the upper plate. This introduces changes in the slip rate on different fault segments, and therefore on the loading rate at the plate interface, profoundly affecting the pattern of earthquake cycles. We develop numerical simulations of slip evolution under rate-and-state friction and show that this effect introduces segmentation of the earthquake cycle. In crustal dynamics, it is challenging to describe the dynamics of fault-bend folds, because the deformation is accommodated by small amounts of slip parallel to bedding planes ("flexural slip"), localized on axial surface, i.e. folding axes pinned to fault bends. We use dislocation theory to describe the dynamics of folding along these axial surfaces, using analytic solutions that provide displacement and stress kernels to simulate the temporal evolution of folding and assess the effects of folding on earthquake cycles. Studies of the 2015 Gorkha earthquake, Nepal, have shown that fault geometry can affect earthquake segmentation. Here, we show that in addition to the fault geometry, the actual geology of the rocks in the hanging wall of the fault also affect critical parameters, including the loading rate on parts of the fault, based on fault-bend folding theory. Because loading velocity controls the recurrence time of earthquakes, these two effects together are likely to have a strong impact on the earthquake cycle.

Thermomechanical earthquake cycle simulations with rate-and-state friction and nonlinear viscoelasticity

NASA Astrophysics Data System (ADS)

Allison, K. L.; Dunham, E. M.

2017-12-01

We simulate earthquake cycles on a 2D strike-slip fault, modeling both rate-and-state fault friction and an off-fault nonlinear power-law rheology. The power-law rheology involves an effective viscosity that is a function of temperature and stress, and therefore varies both spatially and temporally. All phases of the earthquake cycle are simulated, allowing the model to spontaneously generate earthquakes, and to capture frictional afterslip and postseismic and interseismic viscous flow. We investigate the interaction between fault slip and bulk viscous flow, using experimentally-based flow laws for quartz-diorite in the crust and olivine in the mantle, representative of the Mojave Desert region in Southern California. We first consider a suite of three linear geotherms which are constant in time, with dT/dz = 20, 25, and 30 K/km. Though the simulations produce very different deformation styles in the lower crust, ranging from significant interseismc fault creep to purely bulk viscous flow, they have almost identical earthquake recurrence interval, nucleation depth, and down-dip coseismic slip limit. This indicates that bulk viscous flow and interseismic fault creep load the brittle crust similarly. The simulations also predict unrealistically high stresses in the upper crust, resulting from the fact that the lower crust and upper mantle are relatively weak far from the fault, and from the relatively small role that basal tractions on the base of the crust play in the force balance of the lithosphere. We also find that for the warmest model, the effective viscosity varies by an order of magnitude in the interseismic period, whereas for the cooler models it remains roughly constant. Because the rheology is highly sensitive to changes in temperature, in addition to the simulations with constant temperature we also consider the effect of heat generation. We capture both frictional heat generation and off-fault viscous shear heating, allowing these in turn to alter the effective viscosity. The resulting temperature changes may reduce the width of the shear zone in the lower crust and upper mantle, and reduce the effective viscosity.

Region stability analysis and tracking control of memristive recurrent neural network.

PubMed

Bao, Gang; Zeng, Zhigang; Shen, Yanjun

2018-02-01

Memristor is firstly postulated by Leon Chua and realized by Hewlett-Packard (HP) laboratory. Research results show that memristor can be used to simulate the synapses of neurons. This paper presents a class of recurrent neural network with HP memristors. Firstly, it shows that memristive recurrent neural network has more compound dynamics than the traditional recurrent neural network by simulations. Then it derives that n dimensional memristive recurrent neural network is composed of [Formula: see text] sub neural networks which do not have a common equilibrium point. By designing the tracking controller, it can make memristive neural network being convergent to the desired sub neural network. At last, two numerical examples are given to verify the validity of our result. Copyright © 2017 Elsevier Ltd. All rights reserved.

Backward bifurcations, turning points and rich dynamics in simple disease models.

PubMed

Zhang, Wenjing; Wahl, Lindi M; Yu, Pei

2016-10-01

In this paper, dynamical systems theory and bifurcation theory are applied to investigate the rich dynamical behaviours observed in three simple disease models. The 2- and 3-dimensional models we investigate have arisen in previous investigations of epidemiology, in-host disease, and autoimmunity. These closely related models display interesting dynamical behaviors including bistability, recurrence, and regular oscillations, each of which has possible clinical or public health implications. In this contribution we elucidate the key role of backward bifurcations in the parameter regimes leading to the behaviors of interest. We demonstrate that backward bifurcations with varied positions of turning points facilitate the appearance of Hopf bifurcations, and the varied dynamical behaviors are then determined by the properties of the Hopf bifurcation(s), including their location and direction. A Maple program developed earlier is implemented to determine the stability of limit cycles bifurcating from the Hopf bifurcation. Numerical simulations are presented to illustrate phenomena of interest such as bistability, recurrence and oscillation. We also discuss the physical motivations for the models and the clinical implications of the resulting dynamics.

Measurement of uterine natural killer cell percentage in the periimplantation endometrium from fertile women and women with recurrent reproductive failure: establishment of a reference range.

PubMed

Chen, Xiaoyan; Mariee, Najat; Jiang, Lingming; Liu, Yingyu; Wang, Chi Chiu; Li, Tin Chiu; Laird, Susan

2017-12-01

Uterine natural killer cells are the major leukocytes present in the periimplantation endometrium. Previous studies have found controversial differences in uterine natural killer cell percentage in women with recurrent reproductive failure compared with fertile controls. We sought to compare the uterine natural killer cell percentage in women with recurrent reproductive failure and fertile controls. This was a retrospective study carried out in university hospitals. A total of 215 women from 3 university centers participated in the study, including 97 women with recurrent miscarriage, 34 women with recurrent implantation failure, and 84 fertile controls. Endometrial biopsy samples were obtained precisely 7 days after luteinization hormone surge in a natural cycle. Endometrial sections were immunostained for CD56 and cell counting was performed by a standardized protocol. Results were expressed as percentage of positive uterine natural killer cell/total stromal cells. The median uterine natural killer cell percentage in Chinese ovulatory fertile controls in natural cycles was 2.5% (range 0.9-5.3%). Using 5th and 95th percentile to define the lower and upper limits of uterine natural killer cell percentage, the reference range was 1.2-4.5%. Overall, the groups with recurrent reproductive failure had significantly higher uterine natural killer cell percentage than the controls (recurrent miscarriage: median 3.2%, range 0.6-8.8%; recurrent implantation failure: median 3.1%, range 0.8-8.3%). However, there was a subset of both groups (recurrent miscarriage: 16/97; recurrent implantation failure: 6/34) that had lower uterine natural killer cell percentage compared to fertile controls. A reference range for uterine natural killer cell percentage in fertile women was established. Women with recurrent reproductive failure had uterine natural killer cell percentages both above and below the reference range. Copyright © 2017 Elsevier Inc. All rights reserved.

Biologic Determinants of Tumor Recurrence in Stage II Colon Cancer: Validation Study of the 12-Gene Recurrence Score in Cancer and Leukemia Group B (CALGB) 9581

PubMed Central

Venook, Alan P.; Niedzwiecki, Donna; Lopatin, Margarita; Ye, Xing; Lee, Mark; Friedman, Paula N.; Frankel, Wendy; Clark-Langone, Kim; Millward, Carl; Shak, Steven; Goldberg, Richard M.; Mahmoud, Najjia N.; Warren, Robert S.; Schilsky, Richard L.; Bertagnolli, Monica M.

2013-01-01

Purpose A greater understanding of the biology of tumor recurrence should improve adjuvant treatment decision making. We conducted a validation study of the 12-gene recurrence score (RS), a quantitative assay integrating stromal response and cell cycle gene expression, in tumor specimens from patients enrolled onto Cancer and Leukemia Group B (CALGB) 9581. Patients and Methods CALGB 9581 randomly assigned 1,713 patients with stage II colon cancer to treatment with edrecolomab or observation and found no survival difference. The analysis reported here included all patients with available tissue and recurrence (n = 162) and a random (approximately 1:3) selection of nonrecurring patients. RS was assessed in 690 formalin-fixed paraffin-embedded tumor samples with quantitative reverse transcriptase polymerase chain reaction by using prespecified genes and a previously validated algorithm. Association of RS and recurrence was analyzed by weighted Cox proportional hazards regression. Results Continuous RS was significantly associated with risk of recurrence (P = .013) as was mismatch repair (MMR) gene deficiency (P = .044). In multivariate analyses, RS was the strongest predictor of recurrence (P = .004), independent of T stage, MMR, number of nodes examined, grade, and lymphovascular invasion. In T3 MMR-intact (MMR-I) patients, prespecified low and high RS groups had average 5-year recurrence risks of 13% (95% CI, 10% to 16%) and 21% (95% CI, 16% to 26%), respectively. Conclusion The 12-gene RS predicts recurrence in stage II colon cancer in CALGB 9581. This is consistent with the importance of stromal response and cell cycle gene expression in colon tumor recurrence. RS appears to be most discerning for patients with T3 MMR-I tumors, although markers such as grade and lymphovascular invasion did not add value in this subset of patients. PMID:23530100

Clinical significance of repeat blood cultures during febrile neutropenia in adult acute myeloid leukaemia patients undergoing intensive chemotherapy.

PubMed

Kimura, Shun-Ichi; Gomyo, Ayumi; Hayakawa, Jin; Tamaki, Masaharu; Akahoshi, Yu; Harada, Naonori; Ugai, Tomotaka; Kusuda, Machiko; Kameda, Kazuaki; Wada, Hidenori; Ishihara, Yuko; Kawamura, Koji; Sakamoto, Kana; Sato, Miki; Terasako-Saito, Kiriko; Kikuchi, Misato; Nakasone, Hideki; Kako, Shinichi; Tanihara, Aki; Kanda, Yoshinobu

2017-10-01

We evaluated the clinical significance of repeat blood cultures in persistent and recurrent fever during neutropenia in adult acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) patients undergoing intensive chemotherapy. We retrospectively reviewed the chemotherapy cycles at our centre between January 2007 and December 2015. Blood cultures obtained within three days after initial febrile neutropenia (FN) were defined as initial blood cultures and those obtained on or after day 4 were defined as repeat blood cultures. Overall, 321 chemotherapy cycles in 89 patients were subjected to review. FN was identified in 276 (86.0%) chemotherapy cycles. In persistent FN (134 episodes), the causative pathogens were detected by repeat blood cultures in seven episodes (5.2%), including only three episodes (2.2%) of new infection. Shaking chills and high body temperature were identified as significant predictors for bloodstream infection (BSI). In recurrent FN (85 episodes), the causative pathogens were detected in seven episodes (8.2%), and all of these were new organisms. The frequency of detecting new pathogens by repeat blood cultures in recurrent FN (7/85) was higher than that in persistent FN (3/134) (p = .0491). A history of recent BSI was identified as a significant predictor for BSI in recurrent FN. The diagnostic yield of repeat blood cultures for persistent FN was low in intensive chemotherapy for AML and MDS. The frequency of repeat blood cultures for persistent FN could be reduced based on predictors. On the other hand, blood cultures were considered to be essential in cases with recurrent FN.

Boron neutron capture therapy induces cell cycle arrest and cell apoptosis of glioma stem/progenitor cells in vitro.

PubMed

Sun, Ting; Zhang, Zizhu; Li, Bin; Chen, Guilin; Xie, Xueshun; Wei, Yongxin; Wu, Jie; Zhou, Youxin; Du, Ziwei

2013-08-06

Glioma stem cells in the quiescent state are resistant to clinical radiation therapy. An almost inevitable glioma recurrence is due to the persistence of these cells. The high linear energy transfer associated with boron neutron capture therapy (BNCT) could kill quiescent and proliferative cells. The present study aimed to evaluate the effects of BNCT on glioma stem/progenitor cells in vitro. The damage induced by BNCT was assessed using cell cycle progression, apoptotic cell ratio and apoptosis-associated proteins expression. The surviving fraction and cell viability of glioma stem/progenitor cells were decreased compared with differentiated glioma cells using the same boronophenylalanine pretreatment and the same dose of neutron flux. BNCT induced cell cycle arrest in the G2/M phase and cell apoptosis via the mitochondrial pathway, with changes in the expression of associated proteins. Glioma stem/progenitor cells, which are resistant to current clinical radiotherapy, could be effectively killed by BNCT in vitro via cell cycle arrest and apoptosis using a prolonged neutron irradiation, although radiosensitivity of glioma stem/progenitor cells was decreased compared with differentiated glioma cells when using the same dose of thermal neutron exposure and boronophenylalanine pretreatment. Thus, BNCT could offer an appreciable therapeutic advantage to prevent tumor recurrence, and may become a promising treatment in recurrent glioma.

Earthquake cycle simulations with rate-and-state friction and power-law viscoelasticity

NASA Astrophysics Data System (ADS)

Allison, Kali L.; Dunham, Eric M.

2018-05-01

We simulate earthquake cycles with rate-and-state fault friction and off-fault power-law viscoelasticity for the classic 2D antiplane shear problem of a vertical, strike-slip plate boundary fault. We investigate the interaction between fault slip and bulk viscous flow with experimentally-based flow laws for quartz-diorite and olivine for the crust and mantle, respectively. Simulations using three linear geotherms (dT/dz = 20, 25, and 30 K/km) produce different deformation styles at depth, ranging from significant interseismic fault creep to purely bulk viscous flow. However, they have almost identical earthquake recurrence interval, nucleation depth, and down-dip coseismic slip limit. Despite these similarities, variations in the predicted surface deformation might permit discrimination of the deformation mechanism using geodetic observations. Additionally, in the 25 and 30 K/km simulations, the crust drags the mantle; the 20 K/km simulation also predicts this, except within 10 km of the fault where the reverse occurs. However, basal tractions play a minor role in the overall force balance of the lithosphere, at least for the flow laws used in our study. Therefore, the depth-integrated stress on the fault is balanced primarily by shear stress on vertical, fault-parallel planes. Because strain rates are higher directly below the fault than far from it, stresses are also higher. Thus, the upper crust far from the fault bears a substantial part of the tectonic load, resulting in unrealistically high stresses. In the real Earth, this might lead to distributed plastic deformation or formation of subparallel faults. Alternatively, fault pore pressures in excess of hydrostatic and/or weakening mechanisms such as grain size reduction and thermo-mechanical coupling could lower the strength of the ductile fault root in the lower crust and, concomitantly, off-fault upper crustal stresses.

Collisional effects on the numerical recurrence in Vlasov-Poisson simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pezzi, Oreste; Valentini, Francesco; Camporeale, Enrico

The initial state recurrence in numerical simulations of the Vlasov-Poisson system is a well-known phenomenon. Here, we study the effect on recurrence of artificial collisions modeled through the Lenard-Bernstein operator [A. Lenard and I. B. Bernstein, Phys. Rev. 112, 1456–1459 (1958)]. By decomposing the linear Vlasov-Poisson system in the Fourier-Hermite space, the recurrence problem is investigated in the linear regime of the damping of a Langmuir wave and of the onset of the bump-on-tail instability. The analysis is then confirmed and extended to the nonlinear regime through an Eulerian collisional Vlasov-Poisson code. It is found that, despite being routinely used,more » an artificial collisionality is not a viable way of preventing recurrence in numerical simulations without compromising the kinetic nature of the solution. Moreover, it is shown how numerical effects associated to the generation of fine velocity scales can modify the physical features of the system evolution even in nonlinear regime. This means that filamentation-like phenomena, usually associated with low amplitude fluctuations contexts, can play a role even in nonlinear regime.« less

Intraperitoneal chemotherapy for advanced ovarian and peritoneal cancers in patients following interval debulking surgery or primary cytoreductive surgery: Tom Baker Cancer Centre experience from 2006 to 2009.

PubMed

Nelson, Gregory; Lucero, Carlos Aspe; Chu, Pamela; Nation, Jill; Ghatage, Prafull

2010-03-01

To describe our experience with cisplatin- and paclitaxel-based IP chemotherapy in patients treated initially with either neoadjuvant chemotherapy and interval debulking surgery (IDS) or primary cytoreductive surgery (PCRS). We performed a retrospective review of the records of 67 patients (38 IDS, 29 PCRS) enrolled in the intraperitoneal (IP) chemotherapy program at the Tom Baker Cancer Centre between 2006 and 2009. Information pertaining to patient demographics, IP chemotherapy toxicity, and catheter complications was extracted, and the median time to recurrence was calculated. Most patients in the study were aged 50 to 70 years and had a diagnosis of stage III serous ovarian cancer. Overall, 295/393 IP cycles (75%) were successfully administered. The proportion of patients completing six cycles of chemotherapy in the IDS and PCRS groups was 53% and 59%, respectively. Frequent (> 25%) Grade 1 to 2 chemotherapy toxicities included fatigue, peripheral neuropathy, and nausea. Catheter complications were observed in 34% of patients (23/67). The recurrence rates for patients completing four or more cycles of IP chemotherapy in the IDS and PCRS groups were 58% and 35%, respectively, with the median time to recurrence approximately one year. Although IP chemotherapy is well tolerated in both IDS and PCRS patients, the median time to recurrence is shorter than expected.

Long-term impacts of recurrent logging and fire in Amazon forests: a modeling study using the Ecosystem Demography Model (ED2)

NASA Astrophysics Data System (ADS)

Longo, M.; Keller, M.; Scaranello, M. A., Sr.; dos-Santos, M. N.; Xu, Y.; Huang, M.; Morton, D. C.

2017-12-01

Logging and understory fires are major drivers of tropical forest degradation, reducing carbon stocks and changing forest structure, composition, and dynamics. In contrast to deforested areas, sites that are disturbed by logging and fires retain some, albeit severely altered, forest structure and function. In this study we simulated selective logging using the Ecosystem Demography Model (ED-2) to investigate the impact of a broad range of logging techniques, harvest intensities, and recurrence cycles on the long-term dynamics of Amazon forests, including the magnitude and duration of changes in forest flammability following timber extraction. Model results were evaluated using eddy covariance towers at logged sites at the Tapajos National Forest in Brazil and data on long-term dynamics reported in the literature. ED-2 is able to reproduce both the fast (< 5yr) recovery of water, energy fluxes compared to flux tower, and the typical, field-observed, decadal time scales for biomass recovery when no additional logging occurs. Preliminary results using the original ED-2 fire model show that canopy cover loss of forests under high-intensity, conventional logging cause sufficient drying to support more intense fires. These results indicate that under intense degradation, forests may shift to novel disturbance regimes, severely reducing carbon stocks, and inducing long-term changes in forest structure and composition from recurrent fires.

Recurrent Education and Lifelong Learning. World Yearbook of Education 1979.

ERIC Educational Resources Information Center

Schuller, Tom, Ed.; Megarry, Jacquetta, Ed.

To bring a comparative education perspective to the practical problems of recurrent education and lifelong learning, the essays in this collection are written by authors from around the world. Parts 1 (Orientation) and 2 (Major Issues) clarify concepts and issues of general application. Topics include work/leisure/education life cycle, definitions…

Recurrent Disruptions of Rituals and Routines in Families with Paternal Alcohol Abuse

ERIC Educational Resources Information Center

Haugland, Bente Storm Mowatt

2005-01-01

Changes in rituals and routines between drinking and sobriety were examined in families in treatment due to paternal alcohol abuse. Information was gathered through a semistructured family interview. Recurrent disruptions of rituals and routines were found between different phases in the drinking cycle. Disruptions were found typically with regard…

Using phyto-recurrent selection to choose Populus genotypes for phytoremediation of landfill leachate

Treesearch

Jill A. Zalesny; Ronald S., Jr. Zalesny; Adam H. Wiese; Richard B. Hall

2006-01-01

Information about the response of Populus genotypes to landfill leachate irrigation is needed, along with efficient methods for choosing genotypes based on leachate composition. We irrigated poplar clones during three cycles of phyto-recurrent selection to test whether genotypes responded differently to leachate and water, and to test whether our...

Choosing tree genotypes for phytoremediation of landfill leachate using phyto-recurrent selection

Treesearch

Jill A. Zalesny; Ronald S., Jr. Zalesny; Adam H. Wiese; Richard B. Hall

2007-01-01

Information about the response of poplar (Populus spp.) genotypes to landfill leachate irrigation is needed, along with efficient methods for choosing genotypes based on leachate composition. Poplar clones were irrigated during three cycles of phyto-recurrent selection to test whether genotypes responded differently to leachate and water, and to test...

Intelligent control of PV system on the basis of the fuzzy recurrent neuronet*

NASA Astrophysics Data System (ADS)

Engel, E. A.; Kovalev, I. V.; Engel, N. E.

2016-04-01

This paper presents the fuzzy recurrent neuronet for PV system’s control. Based on the PV system’s state, the fuzzy recurrent neural net tracks the maximum power point under random perturbations. The validity and advantages of the proposed intelligent control of PV system are demonstrated by numerical simulations. The simulation results show that the proposed intelligent control of PV system achieves real-time control speed and competitive performance, as compared to a classical control scheme on the basis of the perturbation & observation algorithm.

Recurrent Clostridium difficile infections: The importance of the intestinal microbiota

PubMed Central

Zanella Terrier, Marie Céline; Simonet, Martine Louis; Bichard, Philippe; Frossard, Jean Louis

2014-01-01

Clostridium difficile infections (CDI) are a leading cause of antibiotic-associated and nosocomial diarrhea. Despite effective antibiotic treatments, recurrent infections are common. With the recent emergence of hypervirulent isolates of C. difficile, CDI is a growing epidemic with higher rates of recurrence, increasing severity and mortality. Fecal microbiota transplantation (FMT) is an alternative treatment for recurrent CDI. A better understanding of intestinal microbiota and its role in CDI has opened the door to this promising therapeutic approach. FMT is thought to resolve dysbiosis by restoring gut microbiota diversity thereby breaking the cycle of recurrent CDI. Since the first reported use of FMT for recurrent CDI in 1958, systematic reviews of case series and case report have shown its effectiveness with high resolution rates compared to standard antibiotic treatment. This article focuses on current guidelines for CDI treatment, the role of intestinal microbiota in CDI recurrence and current evidence about FMT efficacy, adverse effects and acceptability. PMID:24966611

The underwriting cycle: the rule of six.

PubMed

Rosenblatt, Alice

2004-01-01

The underwriting cycle is a thing of the past for most health insurance companies. There were six primary factors that caused the six-year pattern of the underwriting cycle for 1965-1991. These factors were claims payment cycle time, renewal dates and process, growth versus profit objectives, role of the actuary, rate regulation, and reimbursement methods. Most companies have made major changes to influence these factors, which will prevent a recurrence of the underwriting cycles of the past.

Intravenous human immunoglobulins for refractory recurrent pericarditis: a systematic review of all published cases.

PubMed

Imazio, Massimo; Lazaros, George; Picardi, Elisa; Vasileiou, Panagiotis; Carraro, Mara; Tousoulis, Dimitrios; Belli, Riccardo; Gaita, Fiorenzo

2016-04-01

Refractory recurrent pericarditis is a major clinical challenge after colchicine failure, especially in corticosteroid-dependent patients. Human intravenous immunoglobulins (IVIGs) have been proposed as possible therapeutic options for these cases. The goal of this systematic review is to assess the efficacy and safety of IVIGs in this context. Studies reporting the use of IVIG for the treatment of recurrent pericarditis and published up to October 2014 were searched in several databases. All references found, upon initial assessment at title and abstract level for suitability, were consequently retrieved as full reports for further appraisal. Among the 18 citations retrieved, 17 reports (4 case series and 13 single case reports, with an overall population of 30 patients) were included. The mean disease duration was 14 months and the mean number of recurrences before IVIG was 3. Approximately 47% of patients had idiopathic recurrent pericarditis, 10% had an infective cause, and the remainder a systemic inflammatory disease. Nineteen out of the 30 patients (63.3%) were on corticosteroids at IVIG commencement. IVIGs were generally administered at a dose of 400-500 mg/kg/day for 5 consecutive days with repeated cycles according to the clinical response. Complications were uncommon (headache in ~3%) and not life-threatening. After a mean follow-up of approximately 33th months, recurrences occurred in 26.6% of cases after the first IVIG cycle, and 22 of the 30 patients (73.3%) were recurrence-free. Five patients (16.6%) were on corticosteroids at the end of the follow-up. IVIGs are rapidly acting, well tolerated, and efficacious steroid-sparing agents in refractory pericarditis.

Determination of candidate metabolite biomarkers associated with recurrence of HCV-related hepatocellular carcinoma

PubMed Central

Liu, Zhicheng; Nahon, Pierre; Li, Zaifang; Yin, Peiyuan; Li, Yanli; Amathieu, Roland; Ganne-Carrié, Nathalie; Ziol, Marianne; Sellier, Nicolas; Seror, Olivier; Le Moyec, Laurence; Savarin, Philippe; Xu, Guowang

2018-01-01

Hepatitis C virus (HCV) infection is associated with a high risk of developing hepatocellular carcinoma (HCC) and HCC recurrence remains the primary threat to outcomes after curative therapy. In this study, we compared recurrent and non-recurrent HCC patients treated with radiofrequency ablation (RFA) in order to identify characteristic metabolic profile variations associated with HCC recurrence. Gas chromatography-mass spectrometry (GC-MS) -based metabolomic analyses were conducted on serum samples obtained before and after RFA therapy. Significant variations were observed in metabolites in the glycerolipid, tricarboxylic acid (TCA) cycle, fatty acid, and amino acid pathways between recurrent and non-recurrent patients. Observed differences in metabolites associated with recurrence did not coincide before and after treatment except for fatty acids. Based on the comparison of serum metabolomes between recurrent and non-recurrent patients, key discriminatory metabolites were defined by a random forest (RF) test. Two combinations of these metabolites before and after RFA treatment showed outstanding performance in predicting HCV-related HCC recurrence, they were further confirmed by an external validation set. Our study showed that the determined combination of metabolites may be potential biomarkers for the prediction of HCC recurrence before and after RFA treatment. PMID:29464069

Vincristine, cisplatin, teniposide, and cyclophosphamide combination in the treatment of recurrent or metastatic adrenocortical cancer.

PubMed

Khan, Tanweera S; Sundin, Anders; Juhlin, Claes; Wilander, Erik; Oberg, Kjell; Eriksson, Barbro

2004-01-01

The efficacy and tolerability of a combination of vincristine, cisplatin, teniposide, and cyclophosphamide (OPEC) in 11 patients (median age, 45 yr) with recurrent and/or metastatic adrenocortical cancer (ACC) (seven functional and four nonfunctional) were evaluated. All patients received this regimen after the failure of streptozocin and o,p'-DDD (SO) combination therapy. The regimen comprised cyclophosphamide, 600 mg/m2, and vincristine, 1.5 mg/m2, maximum dose 2.0 mg (d 1); cisplatin, 100 mg/m2 (d 2) and teniposide, 150 mg/m2 (d 4). Cycles were repeated every 4 wk. One to eight cycles (median, six cycles) of OPEC were administered to each patient. The median duration of treatment was 6 mo. The overall 2-yr survival rate was 82% and the median survival since diagnosis was 44 mo while it was 21 mo since start of OPEC therapy. Responses were obtained in nine patients: partial response in two patients, and stable disease in seven patients. The median duration of response was 6.75 mo. A total of 60 cycles of chemotherapy were given to all patients; grade 1-2 toxicity occurred in 57 cycles, while grade 3 toxicity was observed only in two cycles, according to NCI's Common Toxicity Criteria. We conclude that the OPEC regimen may be considered in recurrent or metastatic ACC as a second-line medical treatment. However, the combination is accompanied by considerable side effects and dose modifications are necessary in order to be able to recommend the treatment. This regimen needs further evaluation compared with SO therapy preferably in a randomized multicenter trial.

Boron neutron capture therapy induces cell cycle arrest and cell apoptosis of glioma stem/progenitor cells in vitro

PubMed Central

2013-01-01

Background Glioma stem cells in the quiescent state are resistant to clinical radiation therapy. An almost inevitable glioma recurrence is due to the persistence of these cells. The high linear energy transfer associated with boron neutron capture therapy (BNCT) could kill quiescent and proliferative cells. Methods The present study aimed to evaluate the effects of BNCT on glioma stem/progenitor cells in vitro. The damage induced by BNCT was assessed using cell cycle progression, apoptotic cell ratio and apoptosis-associated proteins expression. Results The surviving fraction and cell viability of glioma stem/progenitor cells were decreased compared with differentiated glioma cells using the same boronophenylalanine pretreatment and the same dose of neutron flux. BNCT induced cell cycle arrest in the G2/M phase and cell apoptosis via the mitochondrial pathway, with changes in the expression of associated proteins. Conclusions Glioma stem/progenitor cells, which are resistant to current clinical radiotherapy, could be effectively killed by BNCT in vitro via cell cycle arrest and apoptosis using a prolonged neutron irradiation, although radiosensitivity of glioma stem/progenitor cells was decreased compared with differentiated glioma cells when using the same dose of thermal neutron exposure and boronophenylalanine pretreatment. Thus, BNCT could offer an appreciable therapeutic advantage to prevent tumor recurrence, and may become a promising treatment in recurrent glioma. PMID:23915425

Debris flow-induced topographic changes: effects of recurrent debris flow initiation.

PubMed

Chen, Chien-Yuan; Wang, Qun

2017-08-12

Chushui Creek in Shengmu Village, Nantou County, Taiwan, was analyzed for recurrent debris flow using numerical modeling and geographic information system (GIS) spatial analysis. The two-dimensional water flood and mudflow simulation program FLO-2D were used to simulate debris flow induced by rainfall during typhoon Herb in 1996 and Mindulle in 2004. Changes in topographic characteristics after the debris flows were simulated for the initiation of hydrological characteristics, magnitude, and affected area. Changes in topographic characteristics included those in elevation, slope, aspect, stream power index (SPI), topographic wetness index (TWI), and hypsometric curve integral (HI), all of which were analyzed using GIS spatial analysis. The results show that the SPI and peak discharge in the basin increased after a recurrence of debris flow. The TWI was higher in 2003 than in 2004 and indicated higher potential of landslide initiation when the slope of the basin was steeper. The HI revealed that the basin was in its mature stage and was shifting toward the old stage. Numerical simulation demonstrated that the parameters' mean depth, maximum depth, affected area, mean flow rate, maximum flow rate, and peak flow discharge were increased after recurrent debris flow, and peak discharge occurred quickly.

UVR2 ensures transgenerational genome stability under simulated natural UV-B in Arabidopsis thaliana

PubMed Central

Willing, Eva-Maria; Piofczyk, Thomas; Albert, Andreas; Winkler, J. Barbro; Schneeberger, Korbinian; Pecinka, Ales

2016-01-01

Ground levels of solar UV-B radiation induce DNA damage. Sessile phototrophic organisms such as vascular plants are recurrently exposed to sunlight and require UV-B photoreception, flavonols shielding, direct reversal of pyrimidine dimers and nucleotide excision repair for resistance against UV-B radiation. However, the frequency of UV-B-induced mutations is unknown in plants. Here we quantify the amount and types of mutations in the offspring of Arabidopsis thaliana wild-type and UV-B-hypersensitive mutants exposed to simulated natural UV-B over their entire life cycle. We show that reversal of pyrimidine dimers by UVR2 photolyase is the major mechanism required for sustaining plant genome stability across generations under UV-B. In addition to widespread somatic expression, germline-specific UVR2 activity occurs during late flower development, and is important for ensuring low mutation rates in male and female cell lineages. This allows plants to maintain genome integrity in the germline despite exposure to UV-B. PMID:27905394

An in silico evaluation of treatment regimens for recurrent Clostridium difficile infection

PubMed Central

Blanco, Natalia; Foxman, Betsy; Malani, Anurag N.; Zhang, Min; Walk, Seth; Rickard, Alexander H.

2017-01-01

Background Clostridium difficile infection (CDI) is a significant nosocomial infection worldwide, that recurs in as many as 35% of infections. Risk of CDI recurrence varies by ribotype, which also vary in sporulation and germination rates. Whether sporulation/germination mediate risk of recurrence and effectiveness of treatment of recurring CDI remains unclear. We aim to assess the role of sporulation/germination patterns on risk of recurrence, and the relative effectiveness of the recommended tapered/pulsing regimens using an in silico model. Methods We created a compartmental in-host mathematical model of CDI, composed of vegetative cells, toxins, and spores, to explore whether sporulation and germination have an impact on recurrence rates. We also simulated the effectiveness of three tapered/pulsed vancomycin regimens by ribotype. Results Simulations underscored the importance of sporulation/germination patterns in determining pathogenicity and transmission. All recommended regimens for recurring CDI tested were effective in reducing risk of an additional recurrence. Most modified regimens were still effective even after reducing the duration or dosage of vancomycin. However, the effectiveness of treatment varied by ribotype. Conclusion Current CDI vancomycin regimen for treating recurrent cases should be studied further to better balance associated risks and benefits. PMID:28800598

Gradient calculations for dynamic recurrent neural networks: a survey.

PubMed

Pearlmutter, B A

1995-01-01

Surveys learning algorithms for recurrent neural networks with hidden units and puts the various techniques into a common framework. The authors discuss fixed point learning algorithms, namely recurrent backpropagation and deterministic Boltzmann machines, and nonfixed point algorithms, namely backpropagation through time, Elman's history cutoff, and Jordan's output feedback architecture. Forward propagation, an on-line technique that uses adjoint equations, and variations thereof, are also discussed. In many cases, the unified presentation leads to generalizations of various sorts. The author discusses advantages and disadvantages of temporally continuous neural networks in contrast to clocked ones continues with some "tricks of the trade" for training, using, and simulating continuous time and recurrent neural networks. The author presents some simulations, and at the end, addresses issues of computational complexity and learning speed.

Synthesis of recurrent neural networks for dynamical system simulation.

PubMed

Trischler, Adam P; D'Eleuterio, Gabriele M T

2016-08-01

We review several of the most widely used techniques for training recurrent neural networks to approximate dynamical systems, then describe a novel algorithm for this task. The algorithm is based on an earlier theoretical result that guarantees the quality of the network approximation. We show that a feedforward neural network can be trained on the vector-field representation of a given dynamical system using backpropagation, then recast it as a recurrent network that replicates the original system's dynamics. After detailing this algorithm and its relation to earlier approaches, we present numerical examples that demonstrate its capabilities. One of the distinguishing features of our approach is that both the original dynamical systems and the recurrent networks that simulate them operate in continuous time. Copyright © 2016 Elsevier Ltd. All rights reserved.

The outburst duration and duty cycle of GRS1915+105

NASA Astrophysics Data System (ADS)

Deegan, Patrick; Combet, Céline; Wynn, Graham A.

2009-12-01

The extraordinarily long outburst of GRS1915+105 makes it one of the most remarkable low-mass X-ray binaries (LMXBs). It has been in a state of constant outburst since its discovery in 1992, an eruption which has persisted ~100 times longer than those of more typical LXMBs. The long orbital period of GRS1915+105 implies that it contains large and massive accretion disc which is able to fuel its extreme outburst. In this paper, we address the longevity of the outburst and quiescence phases of GRS1915+105 using smooth particle hydrodynamics (SPH) simulations of its accretion disc through many outburst cycles. Our model is set in the two-α framework and includes the effects of the thermoviscous instability, tidal torques, irradiation by central X-rays and wind mass loss. We explore the model parameter space and examine the impact of the various ingredients. We predict that the outburst of GRS1915+105 should last a minimum of 20yr and possibly up to ~100yr if X-ray irradiation is very significant. The predicted recurrence times are of the order of 104yr, making the X-ray duty cycle a few 0.1 per cent. Such a low duty cycle may mean that GRS1915+105 is not an anomaly among the more standard LMXBs and that many similar, but quiescent, systems could be present in the Galaxy.

Effect of dilution in asymmetric recurrent neural networks.

PubMed

Folli, Viola; Gosti, Giorgio; Leonetti, Marco; Ruocco, Giancarlo

2018-04-16

We study with numerical simulation the possible limit behaviors of synchronous discrete-time deterministic recurrent neural networks composed of N binary neurons as a function of a network's level of dilution and asymmetry. The network dilution measures the fraction of neuron couples that are connected, and the network asymmetry measures to what extent the underlying connectivity matrix is asymmetric. For each given neural network, we study the dynamical evolution of all the different initial conditions, thus characterizing the full dynamical landscape without imposing any learning rule. Because of the deterministic dynamics, each trajectory converges to an attractor, that can be either a fixed point or a limit cycle. These attractors form the set of all the possible limit behaviors of the neural network. For each network we then determine the convergence times, the limit cycles' length, the number of attractors, and the sizes of the attractors' basin. We show that there are two network structures that maximize the number of possible limit behaviors. The first optimal network structure is fully-connected and symmetric. On the contrary, the second optimal network structure is highly sparse and asymmetric. The latter optimal is similar to what observed in different biological neuronal circuits. These observations lead us to hypothesize that independently from any given learning model, an efficient and effective biologic network that stores a number of limit behaviors close to its maximum capacity tends to develop a connectivity structure similar to one of the optimal networks we found. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

[Recurrence plot analysis of HRV for brain ischemia and asphyxia].

PubMed

Chen, Xiaoming; Qiu, Yihong; Zhu, Yisheng

2008-02-01

Heart rate variability (HRV) is the tiny variability existing in the cycles of the heart beats, which reflects the corresponding balance between sympathetic and vagus nerves. Since the nonlinear characteristic of HRV is confirmed, the Recurrence Plot method, a nonlinear dynamic analysis method based on the complexity, could be used to analyze HRV. The results showed the recurrence plot structures and some quantitative indices (L-Mean, L-Entr) during asphyxia insult vary significantly as compared to those in normal conditions, which offer a new method to monitor brain asphyxia injury.

Basic emotions and adaptation. A computational and evolutionary model.

PubMed

Pacella, Daniela; Ponticorvo, Michela; Gigliotta, Onofrio; Miglino, Orazio

2017-01-01

The core principles of the evolutionary theories of emotions declare that affective states represent crucial drives for action selection in the environment and regulated the behavior and adaptation of natural agents in ancestrally recurrent situations. While many different studies used autonomous artificial agents to simulate emotional responses and the way these patterns can affect decision-making, few are the approaches that tried to analyze the evolutionary emergence of affective behaviors directly from the specific adaptive problems posed by the ancestral environment. A model of the evolution of affective behaviors is presented using simulated artificial agents equipped with neural networks and physically inspired on the architecture of the iCub humanoid robot. We use genetic algorithms to train populations of virtual robots across generations, and investigate the spontaneous emergence of basic emotional behaviors in different experimental conditions. In particular, we focus on studying the emotion of fear, therefore the environment explored by the artificial agents can contain stimuli that are safe or dangerous to pick. The simulated task is based on classical conditioning and the agents are asked to learn a strategy to recognize whether the environment is safe or represents a threat to their lives and select the correct action to perform in absence of any visual cues. The simulated agents have special input units in their neural structure whose activation keep track of their actual "sensations" based on the outcome of past behavior. We train five different neural network architectures and then test the best ranked individuals comparing their performances and analyzing the unit activations in each individual's life cycle. We show that the agents, regardless of the presence of recurrent connections, spontaneously evolved the ability to cope with potentially dangerous environment by collecting information about the environment and then switching their behavior to a genetically selected pattern in order to maximize the possible reward. We also prove the determinant presence of an internal time perception unit for the robots to achieve the highest performance and survivability across all conditions.

'It seems like you're going around in circles': recurrent biographical disruption constructed through the past, present and anticipated future in the narratives of young adults with inflammatory bowel disease.

PubMed

Saunders, Benjamin

2017-06-01

Biographical disruption and related concepts continue to be widely drawn upon in explaining how individuals experience chronic illness. Through in-depth examination of the narrative experiences of two young adults with inflammatory bowel disease (IBD), this article aims to contribute to the continuing theoretical elaboration of biographical disruption, and in turn offer new insights into how young adults experience this condition. The cases are analysed from an interaction-based, constructionist perspective, through which it is argued that the relapse-remission nature of IBD can give rise to a particular form of recurrent biographical disruption, constructed in narrative through a complex configuration of past, present and anticipated future experiences. The two young adults are found to give different meaning to this recurrent disruption in terms of its significance and consequences - whilst Samuel represents an ongoing cycle of profound disruption and biographical reinstatement, Edith normalises the cycle of disruption and its role in her ongoing biography. Therefore, moving beyond the notion of 'normal illness' observed in previous research literature, the concept of 'normal recurrent disruption' is proposed. Finally, it is argued that this recurrent biographical disruption may be experienced particularly severely in young adulthood owing to the unique pressures and expectations of this lifestage. © 2017 Foundation for the Sociology of Health & Illness.

Potential role of vegetation dynamics on recent extreme droughts over tropical South America

NASA Astrophysics Data System (ADS)

Wang, G.; Erfanian, A.; Fomenko, L.

2017-12-01

Tropical South America is a drought hot spot. In slightly over a decade (2005-2016), the region encountered three extreme droughts (2005, 2010, and 2016). Recurrent extreme droughts not only impact the region's eco-hydrology and socio-economy, but are also globally important as they can transform the planet's largest rainforest, the Amazon, from a carbon sink to a carbon source. Understanding drought drivers and mechanisms underlying extreme droughts in tropical South America can help better project the fate of the Amazon rainforest in a changing climate. In this study we use a regional climate model (RegCM4.3.4) coupled with a comprehensive land-surface model (CLM4.5) to study the present-day hydroclimate of the region, focusing specifically on what might have caused the frequent recurrence of extreme droughts. In the context of observation natural variability of the global oceanic forcing, we tackle the role of land-atmosphere interactions and ran the model with and without dynamic vegetation to study how vegetation dynamics and carbon-nitrogen cycles may have influenced the drought characteristics. Our results demonstrate skillful simulation of the South American climate in the model, and indicate substantial sensitivity of the region's hydroclimatology to vegetation dynamics. This presentation will compare the role of global oceanic forcing versus regional land surface feedback in the recent recurrent droughts, and will characterize the effects of vegetation dynamics in enhancing the drought severity. Preliminary results on future projections of the regional ecosystem and droughts perspective will be also presented.

Growth Cycles of Brain and Mind.

ERIC Educational Resources Information Center

Rose, Samuel P.; Fischer, Kurt W.

1998-01-01

Whereas prior conceptions treated cognitive development as a sequence of stages, current research points to recurring growth cycles between birth and age 30. Each recurrence produces a new capacity for thinking and learning grounded in an expanded, reorganized neural network. Cognitive spurts are evident only under optimal support conditions.…

Simulated systemic recurrent Mycoplasma infection in rats induces recurrent sickness responses without residual impairment in spatial learning and memory.

PubMed

Swanepoel, Tanya; Harvey, Brian H; Harden, Lois M; Laburn, Helen P; Mitchell, Duncan

2012-02-01

In spite of their prevalence and importance, recurrent acute infections seldom have been investigated in the laboratory. We set out to measure fever and sickness behaviour in simulated recurrent Mycoplasma infection; Mycoplasma is a common clinical cause of recurrent acute infection. Male Sprague-Dawley rats had radiotransponders implanted to measure abdominal temperature and cage activity. After recovery, rats received three intraperitoneal (I.P.) injections, 10 days apart, of either fibroblast-stimulating lipopeptide-1 (FLS-1), a pyrogenic moiety of Mycoplasma salivarium, at a dose of 500 μg.kg(-1) in 1 ml.kg(-1) phosphate-buffered saline (PBS), or vehicle (PBS, 1 ml.kg(-1)). Body mass and food intake were measured daily. For measurement of learning and memory, training in a Morris Water Maze commenced 10 days after the last of the three successive injections and continued daily for 4 days. Spatial memory was assessed on the following day. Hippocampal tissue of rats was collected on the day of the last exposure to the maze. Recurrent FSL-1 administration induced recurrent fevers (~1°C) for about 9h, recurrent lethargy (~40-60%) for 1 day, recurrent anorexia (~16-30%) for 1 day, and recurrent reductions in the rate of mass gain (~112%) for 1 day, but did not induce persistent stunting. Recurrent FSL-1 administration did not result in tolerance to fever, lethargy or anorexia. There was no residual histological damage to the hippocampus and no residual detrimental effect in learning or memory in rats. Though we cannot extrapolate our results directly to humans, clinical recurrent acute Mycoplasma infection may not impose a high risk of stunting or impaired spatial learning and memory. Copyright © 2011 Elsevier Inc. All rights reserved.

A novel joint-processing adaptive nonlinear equalizer using a modular recurrent neural network for chaotic communication systems.

PubMed

Zhao, Haiquan; Zeng, Xiangping; Zhang, Jiashu; Liu, Yangguang; Wang, Xiaomin; Li, Tianrui

2011-01-01

To eliminate nonlinear channel distortion in chaotic communication systems, a novel joint-processing adaptive nonlinear equalizer based on a pipelined recurrent neural network (JPRNN) is proposed, using a modified real-time recurrent learning (RTRL) algorithm. Furthermore, an adaptive amplitude RTRL algorithm is adopted to overcome the deteriorating effect introduced by the nesting process. Computer simulations illustrate that the proposed equalizer outperforms the pipelined recurrent neural network (PRNN) and recurrent neural network (RNN) equalizers. Copyright © 2010 Elsevier Ltd. All rights reserved.

The potential value of Clostridium difficile vaccine: an economic computer simulation model.

PubMed

Lee, Bruce Y; Popovich, Michael J; Tian, Ye; Bailey, Rachel R; Ufberg, Paul J; Wiringa, Ann E; Muder, Robert R

2010-07-19

Efforts are currently underway to develop a vaccine against Clostridium difficile infection (CDI). We developed two decision analytic Monte Carlo computer simulation models: (1) an Initial Prevention Model depicting the decision whether to administer C. difficile vaccine to patients at-risk for CDI and (2) a Recurrence Prevention Model depicting the decision whether to administer C. difficile vaccine to prevent CDI recurrence. Our results suggest that a C. difficile vaccine could be cost-effective over a wide range of C. difficile risk, vaccine costs, and vaccine efficacies especially, when being used post-CDI treatment to prevent recurrent disease. (c) 2010 Elsevier Ltd. All rights reserved.

The Potential Value of Clostridium difficile Vaccine: An Economic Computer Simulation Model

PubMed Central

Lee, Bruce Y.; Popovich, Michael J.; Tian, Ye; Bailey, Rachel R.; Ufberg, Paul J.; Wiringa, Ann E.; Muder, Robert R.

2010-01-01

Efforts are currently underway to develop a vaccine against Clostridium difficile infection (CDI). We developed two decision analytic Monte Carlo computer simulation models: (1) an Initial Prevention Model depicting the decision whether to administer C. difficile vaccine to patients at-risk for CDI and (2) a Recurrence Prevention Model depicting the decision whether to administer C. difficile vaccine to prevent CDI recurrence. Our results suggest that a C. difficile vaccine could be cost-effective over a wide range of C. difficile risk, vaccine costs, and vaccine efficacies especially when being used post-CDI treatment to prevent recurrent disease. PMID:20541582

Improvement of a popcorn population using selection indexes from a fourth cycle of recurrent selection program carried out in two different environments.

PubMed

Amaral Júnior, A T; Freitas Júnior, S P; Rangel, R M; Pena, G F; Ribeiro, R M; Morais, R C; Schuelter, A R

2010-03-02

We estimated genetic gains for popcorn varieties using selection indexes in a fourth cycle of intrapopulation recurrent selection developed in the campus of the Universidade Estadual do Norte Fluminense. Two hundred full-sib families were obtained from the popcorn population UNB-2U of the third recurrent selection cycle. The progenies were evaluated in a randomized block design with two replications at sites in two different environments: the Colégio Estadual Agrícola Antônio Sarlo, in Campos dos Goytacazes, and the Empresa de Pesquisa Agropecuária do Estado do Rio de Janeiro (PESAGRO-RIO), in Itaocara, both in the State of Rio de Janeiro. There were significant differences between families within sets in all traits, indicating genetic variability that could be exploited in future cycles. Thirty full-sib families were selected to continue the program. The selection indexes used to predict the gains were those of Mulamba and Mock, Smith and Hazel. The best results were obtained with the Mulamba and Mock index, which allowed the prediction of negative gains for the traits number of diseased ears and ears attacked by pests, number of broken plants and lodging, as well as ears with poor husk cover. It also provided higher gains for popping expansion and grain yield than with the other indexes, giving values of 10.55 and 8.50%, respectively, based on tentatively assigned random weights.

Simulating recurrent event data with hazard functions defined on a total time scale.

PubMed

Jahn-Eimermacher, Antje; Ingel, Katharina; Ozga, Ann-Kathrin; Preussler, Stella; Binder, Harald

2015-03-08

In medical studies with recurrent event data a total time scale perspective is often needed to adequately reflect disease mechanisms. This means that the hazard process is defined on the time since some starting point, e.g. the beginning of some disease, in contrast to a gap time scale where the hazard process restarts after each event. While techniques such as the Andersen-Gill model have been developed for analyzing data from a total time perspective, techniques for the simulation of such data, e.g. for sample size planning, have not been investigated so far. We have derived a simulation algorithm covering the Andersen-Gill model that can be used for sample size planning in clinical trials as well as the investigation of modeling techniques. Specifically, we allow for fixed and/or random covariates and an arbitrary hazard function defined on a total time scale. Furthermore we take into account that individuals may be temporarily insusceptible to a recurrent incidence of the event. The methods are based on conditional distributions of the inter-event times conditional on the total time of the preceeding event or study start. Closed form solutions are provided for common distributions. The derived methods have been implemented in a readily accessible R script. The proposed techniques are illustrated by planning the sample size for a clinical trial with complex recurrent event data. The required sample size is shown to be affected not only by censoring and intra-patient correlation, but also by the presence of risk-free intervals. This demonstrates the need for a simulation algorithm that particularly allows for complex study designs where no analytical sample size formulas might exist. The derived simulation algorithm is seen to be useful for the simulation of recurrent event data that follow an Andersen-Gill model. Next to the use of a total time scale, it allows for intra-patient correlation and risk-free intervals as are often observed in clinical trial data. Its application therefore allows the simulation of data that closely resemble real settings and thus can improve the use of simulation studies for designing and analysing studies.

Is there a 'pig cycle' in the labour supply of doctors? How training and immigration policies respond to physician shortages.

PubMed

Chojnicki, Xavier; Moullan, Yasser

2018-03-01

Many OECD countries are faced with the considerable challenge of a physician shortage. This paper investigates the strategies that OECD governments adopt and determines whether these policies effectively address these medical shortages. Due to the amount of time medical training requires, it takes longer for an expansion in medical school capacity to have an effect than the recruitment of foreign-trained physicians. Using data obtained from the OECD (2014) and Bhargava et al. (2011), we constructed a unique country-level panel dataset that includes annual data for 17 OECD countries on physician shortages, the number of medical school graduates and immigration and emigration rates from 1991 to 2004. By calculating panel fixed-effect estimates, we find that after a period of medical shortages, OECD governments produce more medical graduates in the long run but in the short term, they primarily recruit from abroad; however, at the same time, certain practising physicians choose to emigrate. Simulation results show the limits of recruiting only abroad in the long term but also highlight its appropriateness for the short term when there is a recurrent cycle of shortages/surpluses in the labour supply of physicians (pig cycle theory). Copyright © 2018 Elsevier Ltd. All rights reserved.

Nankai-Tokai subduction hazard for catastrophe risk modeling

NASA Astrophysics Data System (ADS)

Spurr, D. D.

2010-12-01

The historical record of Nankai subduction zone earthquakes includes nine event sequences over the last 1300 years. Typical characteristic behaviour is evident, with segments rupturing either co-seismically or as two large earthquakes less than 3 yrs apart (active phase), followed by periods of low seismicity lasting 90 - 150 yrs or more. Despite the long historical record, the recurrence behaviour and consequent seismic hazard remain uncertain and controversial. In 2005 the Headquarters for Earthquake Research Promotion (HERP) published models for hundreds of faults as part of an official Japanese seismic hazard map. The HERP models have been widely adopted in part or full both within Japan and by the main international catastrophe risk model companies. The time-dependent recurrence modelling we adopt for the Nankai faults departs considerably from HERP in three main areas: ■ A “Linked System” (LS) source model is used to simulate the strong correlation between segment ruptures evident in the historical record, whereas the HERP recurrence estimates assume the Nankai, Tonankai and Tokai segments rupture independently. The LS component models all historical events with a common rupture recurrence cycle for the three segments. System rupture probabilities are calculated assuming BPT behaviour and parameter uncertainties assessed from the full 1300 yr historical record. ■ An independent, “Tokai Only” (TO) rupture source is used specifically to model potential “Tokai only” earthquakes. There are widely diverging views on the possibility of this segment rupturing independently. Although all historical Tokai ruptures appear to have been composite Tonankai -Tokai earthquakes, the available data do not preclude the possibility of future “Tokai only” events. The HERP model also includes “Tokai only” earthquakes but the recurrence parameters are based on historical composite Tonankai -Tokai ruptures and do not appear to recognise the complex tectonic environment in the Tokai area. ■ For the Nankai and Tonankai segments only, HERP assumed Time-Predictable (TP) recurrence behaviour. The resulting calculated 30 and 50 year rupture probabilities are considerably higher than standard renewal model estimates as used in the adopted model. While perhaps more contentious, the weight of evidence available does not appear to be consistent with TP behaviour. For the adopted modelling the estimated probabilities of no Nankai segment rupture within the next 30 & 50 years are 56% & 27% respectively. The disparity between the models is highlighted by the much lower estimates obtained by HERP (2.5% & 0.039% respectively as at 2006). Even for just the Nankai and Tonankai segments (ie. ignoring Tokai), HERP estimated only 1.7% probability of no rupture in 50yrs. These estimates can be contrasted with the fact that in 2056 (50 yrs from 2006), the elapsed time since the start of the last rupture cycle (112yrs) will still be 5 yrs short of the historical mean recurrence interval since 1360. Net effects on nation-wide catastrophe risk estimates for all earthquake sources depend on modelled exposure distributions but can be as much as a factor of two. The differences are important as they impact on multi-billion dollar international risk transfer programs.

A pilot study differentiating recurrent major depression from bipolar disorder cycling on the depressive pole.

PubMed

Hinz, Marty; Stein, Alvin; Uncini, Thomas

2010-11-09

A novel method for differentiating and treating bipolar disorder cycling on the depressive pole from patients who are suffering a major depressive episode is explored in this work. To confirm the diagnosis of type 1 or type 2 bipolar disorder, the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria require that at least one manic or hypomanic episode be identified. History of one or more manic or hypomanic episodes may be impossible to obtain, representing a potential blind spot in the DSM-IV diagnostic criteria. Many bipolar patients who cycle primarily on the depressive side for many years carry a misdiagnosis of recurrent major depression, leading to treatment with antidepressants that achieve little or no relief of symptoms. This article discusses a novel approach for diagnosing and treating patients with bipolar disorder cycling on the depressive pole versus patients with recurrent major depression. Patients involved in this study were formally diagnosed with recurrent major depression under DSM-IV criteria and had no medical history of mania or hypomania to support the diagnosis of bipolar disorder. All patients had suffered multiple depression treatment failures in the past, when evaluated under DSM-IV guidelines, secondary to administration of antidepressant drugs and/or serotonin with dopamine amino acid precursors. This study contained 1600 patients who were diagnosed with recurrent major depression under the DSM-IV criteria. All patients had no medical history of mania or hypomania. All patients experienced no relief of depression symptoms on level 3 amino acid dosing values of the amino acid precursor dosing protocol. Of 1600 patients studied, 117 (7.3%) nonresponder patients were identified who experienced no relief of depression symptoms when the serotonin and dopamine amino acid precursor dosing values were adjusted to establish urinary serotonin and urinary dopamine levels in the Phase III therapeutic ranges. All of the 117 nonresponders who achieved no relief of depression symptoms were continued on this amino acid dosing value, and a mood-stabilizing drug was started. At this point, complete relief of depression symptoms, under evaluation with DSM-IV criteria, was noted in 114 patients within 1-5 days. With further dose adjustment of the mood-stabilizing drug, the remaining three nonresponders achieved relief of depression symptoms. Resolution of depression symptoms with the addition of a mood-stabilizing drug in combination with proper levels of serotonin and dopamine amino acid precursors was the basis for a clinical diagnosis of bipolar disorder cycling on the depressive pole.

A pilot study differentiating recurrent major depression from bipolar disorder cycling on the depressive pole

PubMed Central

Hinz, Marty; Stein, Alvin; Uncini, Thomas

2010-01-01

Purpose A novel method for differentiating and treating bipolar disorder cycling on the depressive pole from patients who are suffering a major depressive episode is explored in this work. To confirm the diagnosis of type 1 or type 2 bipolar disorder, the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria require that at least one manic or hypomanic episode be identified. History of one or more manic or hypomanic episodes may be impossible to obtain, representing a potential blind spot in the DSM-IV diagnostic criteria. Many bipolar patients who cycle primarily on the depressive side for many years carry a misdiagnosis of recurrent major depression, leading to treatment with antidepressants that achieve little or no relief of symptoms. This article discusses a novel approach for diagnosing and treating patients with bipolar disorder cycling on the depressive pole versus patients with recurrent major depression. Patients and methods Patients involved in this study were formally diagnosed with recurrent major depression under DSM-IV criteria and had no medical history of mania or hypomania to support the diagnosis of bipolar disorder. All patients had suffered multiple depression treatment failures in the past, when evaluated under DSM-IV guidelines, secondary to administration of antidepressant drugs and/or serotonin with dopamine amino acid precursors. Results This study contained 1600 patients who were diagnosed with recurrent major depression under the DSM-IV criteria. All patients had no medical history of mania or hypomania. All patients experienced no relief of depression symptoms on level 3 amino acid dosing values of the amino acid precursor dosing protocol. Of 1600 patients studied, 117 (7.3%) nonresponder patients were identified who experienced no relief of depression symptoms when the serotonin and dopamine amino acid precursor dosing values were adjusted to establish urinary serotonin and urinary dopamine levels in the Phase III therapeutic ranges. All of the 117 nonresponders who achieved no relief of depression symptoms were continued on this amino acid dosing value, and a mood-stabilizing drug was started. At this point, complete relief of depression symptoms, under evaluation with DSM-IV criteria, was noted in 114 patients within 1–5 days. With further dose adjustment of the mood-stabilizing drug, the remaining three nonresponders achieved relief of depression symptoms. Conclusion Resolution of depression symptoms with the addition of a mood-stabilizing drug in combination with proper levels of serotonin and dopamine amino acid precursors was the basis for a clinical diagnosis of bipolar disorder cycling on the depressive pole. PMID:21173882

Cycles of Discrimination: Older Women, Cumulative Disadvantages, and Retirement Consequences

ERIC Educational Resources Information Center

Davis, Nanette J.

2005-01-01

This article identifies typical life course situations that women experience, which contribute to a cycle of discrimination or a recurrence of disadvantages simply because of their sex, race, or age. Although men suffer social, health, psychological, and economic disadvantages as they age, this article focuses primarily on women as a more deprived…

Earthquake recurrence and risk assessment in circum-Pacific seismic gaps

USGS Publications Warehouse

Thatcher, W.

1989-01-01

THE development of the concept of seismic gaps, regions of low earthquake activity where large events are expected, has been one of the notable achievements of seismology and plate tectonics. Its application to long-term earthquake hazard assessment continues to be an active field of seismological research. Here I have surveyed well documented case histories of repeated rupture of the same segment of circum-Pacific plate boundary and characterized their general features. I find that variability in fault slip and spatial extent of great earthquakes rupturing the same plate boundary segment is typical rather than exceptional but sequences of major events fill identified seismic gaps with remarkable order. Earthquakes are concentrated late in the seismic cycle and occur with increasing size and magnitude. Furthermore, earthquake rup-ture starts near zones of concentrated moment release, suggesting that high-slip regions control the timing of recurrent events. The absence of major earthquakes early in the seismic cycle indicates a more complex behaviour for lower-slip regions, which may explain the observed cycle-to-cycle diversity of gap-filling sequences. ?? 1989 Nature Publishing Group.

Treatment of recurrent Clostridium difficile infection using fecal microbiota transplantation in patients with inflammatory bowel disease.

PubMed

Newman, Krista M; Rank, Kevin M; Vaughn, Byron P; Khoruts, Alexander

2017-05-04

We recently compared results of fecal microbiota transplantation (FMT) in patients with refractory, recurrent Clostridium difficile infection (rCDI), with and without underlying inflammatory bowel disease (IBD). Here we extend this cohort and analyze outcomes in greater detail by subtype of IBD. We find that FMT is generally effective in breaking the cycle of CDI recurrence, but its effects on overall IBD progression are much less predictable. We discuss several challenges intrinsic to this complex clinical situation and outline the next steps that can address these challenges going forward.

Recurrence quantification as potential bio-markers for diagnosis of pre-cancer

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Sabyasachi; Pratiher, Sawon; Barman, Ritwik; Pratiher, Souvik; Pradhan, Asima; Ghosh, Nirmalya; Panigrahi, Prasanta K.

2017-03-01

In this paper, the spectroscopy signals have been analyzed in recurrence plots (RP), and extract recurrence quantification analysis (RQA) parameters from the RP in order to classify the tissues into normal and different precancerous grades. Three RQA parameters have been quantified in order to extract the important features in the spectroscopy data. These features have been fed to different classifiers for classification. Simulation results validate the efficacy of the recurrence quantification as potential bio-markers for diagnosis of pre-cancer.

Application of carbonate cyclostratigraphy and borehole geophysics to delineate porosity and preferential flow in the karst limestone of the Biscayne aquifer, SE Florida

USGS Publications Warehouse

Cunningham, K.J.; Renken, R.A.; Wacker, M.A.; Zygnerski, M.R.; Robinson, E.; Shapiro, A.M.; Wingard, G.L.

2006-01-01

Combined analyses of cores, borehole geophysical logs, and cyclostratigraphy produced a new conceptual hydrogeologic framework for the triple-porosity (matrix, touching-vug, and conduit porosity) karst limestone of the Biscayne aquifer in a 0.65 km2 study area, SE Florida. Vertical lithofacies successions, which have recurrent stacking patterns, fit within high-frequency cycles. We define three ideal high-frequency cycles as: (1) upward-shallowing subtidal cycles, (2) upward-shallowing paralic cycles, and (3) aggradational subtidal cycles. Digital optical borehole images, tracers, and flow meters indicate that there is a predictable vertical pattern of porosity and permeability within the three ideal cycles, because the distribution of porosity and permeability is related to lithofacies. Stratiform zones of high permeability commonly occur just above flooding surfaces in the lower part of upward-shallowing subtidal and paralic cycles, forming preferential groundwater flow zones. Aggradational subtidal cycles are either mostly high-permeability zones or leaky, low-permeability units. In the study area, groundwater flow within stratiform high-permeability zones is through a secondary pore system of touching-vug porosity principally related to molds of burrows and pelecypods and to interburrow vugs. Movement of a dye-tracer pulse observed using a borehole fluid-temperature tool during a conservative tracer test indicates heterogeneous permeability. Advective movement of the tracer appears to be most concentrated within a thin stratiform flow zone contained within the lower part of a high-frequency cycle, indicating a distinctly high relative permeability for this zone. Borehole flow-meter measurements corroborate the relatively high permeability of the flow zone. Identification and mapping of such high-permeability flow zones is crucial to conceptualization of karst groundwater flow within a cyclostratigraphic framework. Many karst aquifers are included in cyclic platform carbonates. Clearly, a cyclostratigraphic approach that translates carbonate aquifer heterogeneity into a consistent framework of correlative units will improve simulation of karst groundwater flow. ?? 2006 Geological Society of America.

Botulinum Toxin for the Management of Sjögren Syndrome-Associated Recurrent Parotitis.

PubMed

O'Neil, Luke M; Palme, Carsten E; Riffat, Faruque; Mahant, Neil

2016-12-01

Recurrent parotitis is a rare manifestation of Sjögren syndrome. The management of recurrent parotitis is challenging because conservative methods may be of limited efficacy and invasive approaches carry the risk of complications. Botulinum toxin has been shown to reduce salivary flow, and consequently, the results of its use in the management of recurrent parotitis have been encouraging. A 65-year-old female patient with recurrent parotitis due to Sjögren syndrome was referred to us, complaining of weekly bouts of inflammation. She required a course of antibiotics monthly to control bacterial superinfections. We treated her with onabotulinumtoxinA injections into both parotid glands at regular intervals. After her second injection cycle, she denied further inflammatory bouts, has not required antibiotics in more than 36 months, and denied any side effects. Botulinum toxin may be a safe and effective method of treating Sjögren syndrome-associated recurrent parotitis. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Coinfection and Emergence of Rifamycin Resistance during a Recurrent Clostridium difficile Infection.

PubMed

Stevenson, Emma C; Major, Giles A; Spiller, Robin C; Kuehne, Sarah A; Minton, Nigel P

2016-11-01

Clostridium difficile (Peptoclostridium difficile) is a common health care-associated infection with a disproportionately high incidence in elderly patients. Disease symptoms range from mild diarrhea to life-threatening pseudomembranous colitis. Around 20% of patients may suffer recurrent disease, which often requires rehospitalization of patients. C. difficile was isolated from stool samples from a patient with two recurrent C. difficile infections. PCR ribotyping, whole-genome sequencing, and phenotypic assays were used to characterize these isolates. Genotypic and phenotypic screening of C. difficile isolates revealed multiple PCR ribotypes present and the emergence of rifamycin resistance during the infection cycle. Understanding both the clinical and bacterial factors that contribute to the course of recurrent infection could inform strategies to reduce recurrence. (This study has been registered at ClinicalTrials.gov under registration no. NCT01670149.). Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Relationships between solar activity and climate change. [sunspot cycle effects on lower atmosphere

NASA Technical Reports Server (NTRS)

Roberts, W. O.

1974-01-01

Recurrent droughts are related to the double sunspot cycle. It is suggested that high solar activity generally increases meridional circulations and blocking patterns at high and intermediate latitudes, especially in winter. This effect is related to the sudden formation of cirrus clouds during strong geomagnetic activity that originates in the solar corpuscular emission.

The 21-gene Recurrence Score® assay predicts distant recurrence in lymph node-positive, hormone receptor-positive, breast cancer patients treated with adjuvant sequential epirubicin- and docetaxel-based or epirubicin-based chemotherapy (PACS-01 trial).

PubMed

Penault-Llorca, Frédérique; Filleron, Thomas; Asselain, Bernard; Baehner, Frederick L; Fumoleau, Pierre; Lacroix-Triki, Magali; Anderson, Joseph M; Yoshizawa, Carl; Cherbavaz, Diana B; Shak, Steven; Roca, Lise; Sagan, Christine; Lemonnier, Jérôme; Martin, Anne-Laure; Roché, Henri

2018-05-04

The 21-gene Recurrence Score (RS) result predicts outcome and chemotherapy benefit in node-negative and node-positive (N+), estrogen receptor-positive (ER+) patients treated with endocrine therapy. The purpose of this study was to evaluate the prognostic impact of RS results in N+, hormone receptor-positive (HR+) patients treated with adjuvant chemotherapy (6 cycles of FEC100 vs. 3 cycles of FEC100 followed by 3 cycles of docetaxel 100 mg/m 2 ) plus endocrine therapy (ET) in the PACS-01 trial (J Clin Oncol 2006;24:5664-5671). The current study included 530 HR+/N+ patients from the PACS-01 parent trial for whom specimens were available. The primary objective was to evaluate the relationship between the RS result and distant recurrence (DR). There were 209 (39.4%) patients with low RS (< 18), 159 (30%) with intermediate RS (18-30) and 162 (30.6%) with high RS (≥ 31). The continuous RS result was associated with DR (hazard ratio = 4.14; 95% confidence interval: 2.67-6.43; p <  0.001), adjusting for treatment. In multivariable analysis, the RS result remained a significant predictor of DR (p <  0.001) after adjustment for number of positive nodes, tumor size, tumor grade, Ki-67 (immunohistochemical status), and chemotherapy regimen. There was no statistically significant interaction between RS result and treatment in predicting DR (p = 0.79). After adjustment for clinical covariates, the 21-gene RS result is a significant prognostic factor in N+/HR+ patients receiving adjuvant chemoendocrine therapy. Not applicable.

Computational fluid dynamics (CFD) using porous media modeling predicts recurrence after coiling of cerebral aneurysms.

PubMed

Umeda, Yasuyuki; Ishida, Fujimaro; Tsuji, Masanori; Furukawa, Kazuhiro; Shiba, Masato; Yasuda, Ryuta; Toma, Naoki; Sakaida, Hiroshi; Suzuki, Hidenori

2017-01-01

This study aimed to predict recurrence after coil embolization of unruptured cerebral aneurysms with computational fluid dynamics (CFD) using porous media modeling (porous media CFD). A total of 37 unruptured cerebral aneurysms treated with coiling were analyzed using follow-up angiograms, simulated CFD prior to coiling (control CFD), and porous media CFD. Coiled aneurysms were classified into stable or recurrence groups according to follow-up angiogram findings. Morphological parameters, coil packing density, and hemodynamic variables were evaluated for their correlations with aneurysmal recurrence. We also calculated residual flow volumes (RFVs), a novel hemodynamic parameter used to quantify the residual aneurysm volume after simulated coiling, which has a mean fluid domain > 1.0 cm/s. Follow-up angiograms showed 24 aneurysms in the stable group and 13 in the recurrence group. Mann-Whitney U test demonstrated that maximum size, dome volume, neck width, neck area, and coil packing density were significantly different between the two groups (P < 0.05). Among the hemodynamic parameters, aneurysms in the recurrence group had significantly larger inflow and outflow areas in the control CFD and larger RFVs in the porous media CFD. Multivariate logistic regression analyses demonstrated that RFV was the only independently significant factor (odds ratio, 1.06; 95% confidence interval, 1.01-1.11; P = 0.016). The study findings suggest that RFV collected under porous media modeling predicts the recurrence of coiled aneurysms.

Cell cycle-coupled expansion of AR activity promotes cancer progression.

PubMed

McNair, C; Urbanucci, A; Comstock, C E S; Augello, M A; Goodwin, J F; Launchbury, R; Zhao, S G; Schiewer, M J; Ertel, A; Karnes, J; Davicioni, E; Wang, L; Wang, Q; Mills, I G; Feng, F Y; Li, W; Carroll, J S; Knudsen, K E

2017-03-23

The androgen receptor (AR) is required for prostate cancer (PCa) survival and progression, and ablation of AR activity is the first line of therapeutic intervention for disseminated disease. While initially effective, recurrent tumors ultimately arise for which there is no durable cure. Despite the dependence of PCa on AR activity throughout the course of disease, delineation of the AR-dependent transcriptional network that governs disease progression remains elusive, and the function of AR in mitotically active cells is not well understood. Analyzing AR activity as a function of cell cycle revealed an unexpected and highly expanded repertoire of AR-regulated gene networks in actively cycling cells. New AR functions segregated into two major clusters: those that are specific to cycling cells and retained throughout the mitotic cell cycle ('Cell Cycle Common'), versus those that were specifically enriched in a subset of cell cycle phases ('Phase Restricted'). Further analyses identified previously unrecognized AR functions in major pathways associated with clinical PCa progression. Illustrating the impact of these unmasked AR-driven pathways, dihydroceramide desaturase 1 was identified as an AR-regulated gene in mitotically active cells that promoted pro-metastatic phenotypes, and in advanced PCa proved to be highly associated with development of metastases, recurrence after therapeutic intervention and reduced overall survival. Taken together, these findings delineate AR function in mitotically active tumor cells, thus providing critical insight into the molecular basis by which AR promotes development of lethal PCa and nominate new avenues for therapeutic intervention.

Simulator fidelity : the effect of platform motion.

DOT National Transportation Integrated Search

2000-07-31

As part of the Federal Aviation Administration's (FAA) initiative towards affordable flight simulators for U.S. commuter airlines, this study empirically examined the effect of six-degree-of-freedom simulator platform motion on recurrent pilot traini...

Comparison of Time-to-First Event and Recurrent Event Methods in Randomized Clinical Trials.

PubMed

Claggett, Brian; Pocock, Stuart; Wei, L J; Pfeffer, Marc A; McMurray, John J V; Solomon, Scott D

2018-03-27

Background -Most Phase-3 trials feature time-to-first event endpoints for their primary and/or secondary analyses. In chronic diseases where a clinical event can occur more than once, recurrent-event methods have been proposed to more fully capture disease burden and have been assumed to improve statistical precision and power compared to conventional "time-to-first" methods. Methods -To better characterize factors that influence statistical properties of recurrent-events and time-to-first methods in the evaluation of randomized therapy, we repeatedly simulated trials with 1:1 randomization of 4000 patients to active vs control therapy, with true patient-level risk reduction of 20% (i.e. RR=0.80). For patients who discontinued active therapy after a first event, we assumed their risk reverted subsequently to their original placebo-level risk. Through simulation, we varied a) the degree of between-patient heterogeneity of risk and b) the extent of treatment discontinuation. Findings were compared with those from actual randomized clinical trials. Results -As the degree of between-patient heterogeneity of risk was increased, both time-to-first and recurrent-events methods lost statistical power to detect a true risk reduction and confidence intervals widened. The recurrent-events analyses continued to estimate the true RR=0.80 as heterogeneity increased, while the Cox model produced estimates that were attenuated. The power of recurrent-events methods declined as the rate of study drug discontinuation post-event increased. Recurrent-events methods provided greater power than time-to-first methods in scenarios where drug discontinuation was ≤30% following a first event, lesser power with drug discontinuation rates of ≥60%, and comparable power otherwise. We confirmed in several actual trials in chronic heart failure that treatment effect estimates were attenuated when estimated via the Cox model and that increased statistical power from recurrent-events methods was most pronounced in trials with lower treatment discontinuation rates. Conclusions -We find that the statistical power of both recurrent-events and time-to-first methods are reduced by increasing heterogeneity of patient risk, a parameter not included in conventional power and sample size formulas. Data from real clinical trials are consistent with simulation studies, confirming that the greatest statistical gains from use of recurrent-events methods occur in the presence of high patient heterogeneity and low rates of study drug discontinuation.

Global exponential periodicity and stability of discrete-time complex-valued recurrent neural networks with time-delays.

PubMed

Hu, Jin; Wang, Jun

2015-06-01

In recent years, complex-valued recurrent neural networks have been developed and analysed in-depth in view of that they have good modelling performance for some applications involving complex-valued elements. In implementing continuous-time dynamical systems for simulation or computational purposes, it is quite necessary to utilize a discrete-time model which is an analogue of the continuous-time system. In this paper, we analyse a discrete-time complex-valued recurrent neural network model and obtain the sufficient conditions on its global exponential periodicity and exponential stability. Simulation results of several numerical examples are delineated to illustrate the theoretical results and an application on associative memory is also given. Copyright © 2015 Elsevier Ltd. All rights reserved.

Genetic gains in the UENF-14 popcorn population with recurrent selection.

PubMed

Freitas, I L J; do Amaral Júnior, A T; Freitas, S P; Cabral, P D S; Ribeiro, R M; Gonçalves, L S A

2014-01-21

The popcorn breeding program of Universidade Estadual do Norte Fluminense Darcy Ribeiro aims to provide farmers a cultivar with desirable agronomic traits, particularly with respect to grain yield (GY) and popping expansion (PE). We evaluated full-sib families from the seventh cycle of recurrent selection and estimated the genetic progress with respect to GY and PE. Eight traits were evaluated in 200 full-sib families that were randomized into blocks with two replicates per set in two contrasting environments, Campos dos Goytacazes and Itaocara, located in north and northwest Rio de Janeiro State, respectively. There were significant differences between sets in families with respect to all traits evaluated, which indicates genetic variability that may be explored in future cycles. Using random economic weights in the selection of superior progenies, the Mulamba and Mock index showed gains for PE and GY of 5.11 and 7.78%, respectively. Significant PE and GY increases were found when comparing the evolution of mean values of these two parameters that were assessed at cycles C₀-C₆ and predicted for C₇. Thus, an advanced-cycle popcorn cultivar with genotypic superiority for the main traits of economic interest can be made available to farmers in Rio de Janeiro State.

[Disturbed respiratory cycle accompanying hypoxic-ischemic encephalopathy].

PubMed

Saito, Yoshiaki; Masuko, Kaori; Kaneko, Kaori; Saito, Kazuyo; Chikumaru, Yuri; Iwamoto, Hiroko; Matsui, Akira; Kimura, Seiji

2005-09-01

We report the case of a 2-year-old boy who experienced total asphyxia at 4 months of age, and suffered abnormalities at specific phases of the respiratory cycle. The patient was bedridden due to severe tetraplegia and showed little response to external stimuli. He has been tube-fed since the initial asphyxia and a tracheotomy was performed after recurrent hypoxic episodes as a result of the respiratory dysfunction. Upon examination, his respiratory pattern was characterized by arrest during the inspiratory phase with a possible over-riding secondary inspiration. The respiratory pause at the inspiratory phase was markedly prolonged during an episode of pulmonary infection, resulting in recurrent cyanosis that necessitated artificial ventilation. The "second" inspiration typically occurred during the mid- or late-inspiratory phases, with this pattern often shown to be variable after epileptic seizures. The characteristic breathing of this patient suggested that difficulty in forming a normal respiratory cycle, other than during periods of hypoventilation or apnoea, could be a significant respiratory dysfunction following asphyxiation. Strategies for the management of such patients should be carefully designed after close observation of breathing patterns within the respiratory cycle, and with consideration for the influence of epileptic seizures and other inputs from somatic afferents.

MicroRNA-Related DNA Repair/Cell-Cycle Genes Independently Associated With Relapse After Radiation Therapy for Early Breast Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gee, Harriet E., E-mail: harriet.gee@sydney.edu.au; The Chris O'Brien Lifehouse, Missenden Road, Camperdown, NSW; Central Clinical School, Sydney Medical School, University of Sydney, NSW

Purpose: Local recurrence and distant failure after adjuvant radiation therapy for breast cancer remain significant clinical problems, incompletely predicted by conventional clinicopathologic markers. We had previously identified microRNA-139-5p and microRNA-1274a as key regulators of breast cancer radiation response in vitro. The purpose of this study was to investigate standard clinicopathologic markers of local recurrence in a contemporary series and to establish whether putative target genes of microRNAs involved in DNA repair and cell cycle control could better predict radiation therapy response in vivo. Methods and Materials: With institutional ethics board approval, local recurrence was measured in a contemporary, prospectively collected series ofmore » 458 patients treated with radiation therapy after breast-conserving surgery. Additionally, independent publicly available mRNA/microRNA microarray expression datasets totaling >1000 early-stage breast cancer patients, treated with adjuvant radiation therapy, with >10 years of follow-up, were analyzed. The expression of putative microRNA target biomarkers—TOP2A, POLQ, RAD54L, SKP2, PLK2, and RAG1—were correlated with standard clinicopathologic variables using 2-sided nonparametric tests, and to local/distant relapse and survival using Kaplan-Meier and Cox regression analysis. Results: We found a low rate of isolated local recurrence (1.95%) in our modern series, and that few clinicopathologic variables (such as lymphovascular invasion) were significantly predictive. In multiple independent datasets (n>1000), however, high expression of RAD54L, TOP2A, POLQ, and SKP2 significantly correlated with local recurrence, survival, or both in univariate and multivariate analyses (P<.001). Low RAG1 expression significantly correlated with local recurrence (multivariate, P=.008). Additionally, RAD54L, SKP2, and PLK2 may be predictive, being prognostic in radiation therapy–treated patients but not in untreated matched control individuals (n=107; P<.05). Conclusions: Biomarkers of DNA repair and cell cycle control can identify patients at high risk of treatment failure in those receiving radiation therapy for early breast cancer in independent cohorts. These should be further investigated prospectively, especially TOP2A and SKP2, for which targeted therapies are available.« less

Recurrent implantation failure in IVF: features of cycles that eventually ended in conception.

PubMed

Bord, Ilia; Tamir, Belle; Harlev, Avraham; Har-Vardi, Iris; Lunenfeld, Eitan; Friger, Michael; Levitas, Eliahu

2016-04-01

To evaluate the characteristics of patients and IVF cycles with recurrent implantation failure who eventually succeeded to conceive compared to those who failed to do so. In a retrospective study, we explored our database for patients younger than 35 years old who underwent at least three unsuccessful fresh IVF cycles. The following parameters were analyzed: cause of infertility, FSH level, stimulation cycle characteristics, fertilization rate, the type of luteal support, and cycle outcome. Uterine cavity assessment was also included. The relationship between endometrial scratching and the outcome of the following IVF cycle was assessed for the subsequent pregnancy rate. The study included 184 patients who underwent 854 IVF cycles. There were no statistically significant differences between patients who eventually conceived and those who did not in terms of ovarian reserve and response to gonadotropin treatment. IVF cycles that eventually ended with conception were characterized by shorter stimulation (10.87 ± 2.17 versus 11.34 ± 2.33 days, p < 0.05), higher estrogen level on the day of hCG administration (1661 ± 667 versus 1472 ± 633 pg/ml, p = 0.009), more fertilized oocytes via ICSI (5.04 ± 4.29 versus 3.85 ± 3.45, p = 0.002), and more embryos available for transfer (5.98 ± 3.89 versus 5.12 ± 3.31, p = 0.002). Combined estrogen and progesterone luteal support combined with endometrial scratching prior to the subsequent IVF cycle has been positively related to increased pregnancy rates. Young patients with RIF having a normal ovarian reserve and satisfactory ovarian response to superovulation should be encouraged to pursue IVF, even though the probability to conceive is relatively low compared to the general IVF population.

14 CFR 135.338 - Qualifications: Flight instructors (aircraft) and flight instructors (simulator).

Code of Federal Regulations, 2010 CFR

2010-01-01

...) Has satisfactorily completed the training phases for the aircraft, including recurrent training, that... satisfactorily completed the appropriate training phases for the aircraft, including recurrent training, that are... AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Training § 135.338 Qualifications: Flight...

On the Bimodality of ENSO Cycle Extremes

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

1999-01-01

On the basis of sea surface temperature in the Nino 3.4 region (5 deg N-5 deg S, 120 deg- 170 deg W) during the interval of 1950-1997, Kevin Trenberth previously has identified some 16 El Nino and 10 La Nina, these 26 events representing the extremes of the quasi-periodic El Nino-Southern Oscillation (ENSO) cycle. Runs testing shows that the duration and recurrence period associated with these extremes vary randomly, as does the sequencing of the extremes. Hence, the frequency of occurrence of these events during the 1990s, especially, for El Nino should not be construed as being significantly different from that of previous epochs. Additionally, the distribution of duration for both El Nino and La Nina looks bimodal, consisting of two preferred modes - about 8 and 16 months in length for El Nino and about 9 and 18 months in length for La Nina. Likewise, the distribution of recurrence period, especially, for El Nino looks bimodal, consisting of two preferred modes - about 21 and 50 months in length. Scatter plots of the recurrence period versus duration for El Nino strongly suggest preferential associations between them, linking shorter (longer) duration with shorter (longer) recurrence period. Because the last known onset of El Nino occurred in April 1997 and the event was of longer than average duration, one infers that the onset of the next expected El Nino will not occur until February 2000 or later.

On the Bimodality of ENSO Cycle Extremes

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2000-01-01

On the basis of sea surface temperature in the El Nino 3.4 region (5 deg. N.,-5 deg. S., 120-170 deg. W.) during the interval of 1950-1997, Kevin Trenberth previously has identified some 16 El Nino and 10 La Nina, these 26 events representing the extremes of the quasi-periodic El Nino-Southern Oscillation (ENSO) cycle. Runs testing shows that the duration, recurrence period, and sequencing of these extremes vary randomly. Hence, the decade of the 1990's, especially for El Nino, is not significantly different from that of previous decadal epochs, at least, on the basis of the frequency of onsets of ENSO extremes. Additionally, the distribution of duration for both El Nino and La Nina looks strikingly bimodal, each consisting of two preferred modes, about 8- and 16-mo long for El Nino and about 9- and 18-mo long for La Nina, as does the distribution of the recurrence period for El Nino, consisting of two preferred modes about 21- and 50-mo long. Scatterplots of the recurrence period versus duration for El Nino are found to be statistically important, displaying preferential associations that link shorter (longer) duration with shorter (longer) recurrence periods. Because the last onset of El Nino occurred in April 1997 and the event was of longer than average duration, onset of the next anticipated El Nino is not expected until February 2000 or later.

On The Bimodality of ENSO Cycle Extremes

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2000-01-01

On the basis of sea surface temperature in the El Nino 3.4 region (5N.-5S., 120-170W.) during the interval of 1950-1997, Kevin Trenberth previously has identified some 16 El Nino and 10 La Nina, these 26 events representing the extremes of the quasi-periodic El Nino-Southern Oscillation (ENSO) cycle. Runs testing shows that the duration, recurrence period, and sequencing of these extremes vary randomly. Hence, the decade of the 1990's, especially for El Nino, is not significantly different from that of previous decadal epochs, at least, on the basis of the frequency of onsets of ENSO extremes. Additionally, the distribution of duration for both El Nino and La Nina looks strikingly bimodal, each consisting of two preferred modes, about 8- and 16-months long for El Nino and about 9- and 18-months long for La Nina, as does the distribution of the recurrence period for El Nino, consisting of two preferred modes about 21- and 50- mo long. Scatterplots of the recurrence period versus duration for El Nino are found to be statistically important, displaying preferential associations that link shorter (longer) duration with shorter (longer) recurrence periods. Because the last onset of El Nino occurred in April 1997 and the event was of longer than average duration, onset of the next anticipated El Nino is not expected until February 2000 or later.

Computational fluid dynamics (CFD) using porous media modeling predicts recurrence after coiling of cerebral aneurysms

PubMed Central

Ishida, Fujimaro; Tsuji, Masanori; Furukawa, Kazuhiro; Shiba, Masato; Yasuda, Ryuta; Toma, Naoki; Sakaida, Hiroshi; Suzuki, Hidenori

2017-01-01

Objective This study aimed to predict recurrence after coil embolization of unruptured cerebral aneurysms with computational fluid dynamics (CFD) using porous media modeling (porous media CFD). Method A total of 37 unruptured cerebral aneurysms treated with coiling were analyzed using follow-up angiograms, simulated CFD prior to coiling (control CFD), and porous media CFD. Coiled aneurysms were classified into stable or recurrence groups according to follow-up angiogram findings. Morphological parameters, coil packing density, and hemodynamic variables were evaluated for their correlations with aneurysmal recurrence. We also calculated residual flow volumes (RFVs), a novel hemodynamic parameter used to quantify the residual aneurysm volume after simulated coiling, which has a mean fluid domain > 1.0 cm/s. Result Follow-up angiograms showed 24 aneurysms in the stable group and 13 in the recurrence group. Mann-Whitney U test demonstrated that maximum size, dome volume, neck width, neck area, and coil packing density were significantly different between the two groups (P < 0.05). Among the hemodynamic parameters, aneurysms in the recurrence group had significantly larger inflow and outflow areas in the control CFD and larger RFVs in the porous media CFD. Multivariate logistic regression analyses demonstrated that RFV was the only independently significant factor (odds ratio, 1.06; 95% confidence interval, 1.01–1.11; P = 0.016). Conclusion The study findings suggest that RFV collected under porous media modeling predicts the recurrence of coiled aneurysms. PMID:29284057

Parallel Multi-cycle LES of an Optical Pent-roof DISI Engine Under Motored Operating Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Dam, Noah; Sjöberg, Magnus; Zeng, Wei

The use of Large-eddy Simulations (LES) has increased due to their ability to resolve the turbulent fluctuations of engine flows and capture the resulting cycle-to-cycle variability. One drawback of LES, however, is the requirement to run multiple engine cycles to obtain the necessary cycle statistics for full validation. The standard method to obtain the cycles by running a single simulation through many engine cycles sequentially can take a long time to complete. Recently, a new strategy has been proposed by our research group to reduce the amount of time necessary to simulate the many engine cycles by running individual enginemore » cycle simulations in parallel. With modern large computing systems this has the potential to reduce the amount of time necessary for a full set of simulated engine cycles to finish by up to an order of magnitude. In this paper, the Parallel Perturbation Methodology (PPM) is used to simulate up to 35 engine cycles of an optically accessible, pent-roof Directinjection Spark-ignition (DISI) engine at two different motored engine operating conditions, one throttled and one un-throttled. Comparisons are made against corresponding sequential-cycle simulations to verify the similarity of results using either methodology. Mean results from the PPM approach are very similar to sequential-cycle results with less than 0.5% difference in pressure and a magnitude structure index (MSI) of 0.95. Differences in cycle-to-cycle variability (CCV) predictions are larger, but close to the statistical uncertainty in the measurement for the number of cycles simulated. PPM LES results were also compared against experimental data. Mean quantities such as pressure or mean velocities were typically matched to within 5- 10%. Pressure CCVs were under-predicted, mostly due to the lack of any perturbations in the pressure boundary conditions between cycles. Velocity CCVs for the simulations had the same average magnitude as experiments, but the experimental data showed greater spatial variation in the root-mean-square (RMS). Conversely, circular standard deviation results showed greater repeatability of the flow directionality and swirl vortex positioning than the simulations.« less

A phase 2 study of the oral mammalian target of rapamycin inhibitor, everolimus, in patients with recurrent endometrial carcinoma.

PubMed

Slomovitz, Brian M; Lu, Karen H; Johnston, Taren; Coleman, Robert L; Munsell, Mark; Broaddus, Russell R; Walker, Cheryl; Ramondetta, Lois M; Burke, Thomas W; Gershenson, David M; Wolf, Judith

2010-12-01

Dysregulation of phosphatase and tensin homolog (PTEN) and the gene that encodes the p110α catalytic subunit of phosphatidylinositol-3-kinase (PI3K), PIK3CA, are the most common mutations in endometrial carcinoma (EC). Loss of PTEN or activation of PIK3CA results in constitutive activation of AKT, which leads to up-regulation of mammalian target of rapamycin (mTOR). Everolimus is an oral rapamycin analog that acts by selectively inhibiting mTOR. A single-institution, open-labeled, phase 2 study of everolimus in patients with measurable recurrent EC who had failed at least 1 and no more than 2 prior chemotherapeutic regimens was performed. Everolimus was administered at a dose of 10 mg orally daily for 28-day cycles. Patients were treated until disease progression or toxicity. The primary endpoint was clinical benefit response (CBR), defined as a confirmed complete or partial response or prolonged stable disease (SD) (≥8 weeks). Inclusion was limited to patients with endometrioid histology. A total of 35 patients were enrolled (median age, 58 years; range, 38-81 years). A total of 81 cycles were administered. Twelve of 28 (43%) evaluable patients had not developed disease progression at the time of the first objective evaluation (8 weeks). All these patients had SD (median, 4.5 cycles; range, 2-10 cycles). Six of the 28 (21%) patients had a confirmed CBR at 20 weeks of therapy. Patients with CBR discontinued treatment because of toxicity (6 patients), disease progression (5 patients), and noncompliance (1 patient). Seven patients were unevaluable after receiving ≤1 cycle because of toxicity (5 patients) or noncompliance (2 patients). The most common drug-related toxicities were fatigue, anemia, pain, lymphopenia, and nausea. Everolimus demonstrated encouraging single-agent CBR in pretreated patients with recurrent endometrioid EC. Future studies will evaluate this agent in combination with hormonal and/or cytotoxic therapy. Copyright © 2010 American Cancer Society.

Basic emotions and adaptation. A computational and evolutionary model

PubMed Central

2017-01-01

The core principles of the evolutionary theories of emotions declare that affective states represent crucial drives for action selection in the environment and regulated the behavior and adaptation of natural agents in ancestrally recurrent situations. While many different studies used autonomous artificial agents to simulate emotional responses and the way these patterns can affect decision-making, few are the approaches that tried to analyze the evolutionary emergence of affective behaviors directly from the specific adaptive problems posed by the ancestral environment. A model of the evolution of affective behaviors is presented using simulated artificial agents equipped with neural networks and physically inspired on the architecture of the iCub humanoid robot. We use genetic algorithms to train populations of virtual robots across generations, and investigate the spontaneous emergence of basic emotional behaviors in different experimental conditions. In particular, we focus on studying the emotion of fear, therefore the environment explored by the artificial agents can contain stimuli that are safe or dangerous to pick. The simulated task is based on classical conditioning and the agents are asked to learn a strategy to recognize whether the environment is safe or represents a threat to their lives and select the correct action to perform in absence of any visual cues. The simulated agents have special input units in their neural structure whose activation keep track of their actual “sensations” based on the outcome of past behavior. We train five different neural network architectures and then test the best ranked individuals comparing their performances and analyzing the unit activations in each individual’s life cycle. We show that the agents, regardless of the presence of recurrent connections, spontaneously evolved the ability to cope with potentially dangerous environment by collecting information about the environment and then switching their behavior to a genetically selected pattern in order to maximize the possible reward. We also prove the determinant presence of an internal time perception unit for the robots to achieve the highest performance and survivability across all conditions. PMID:29107988

Exploration of the recurrence in radiation brain necrosis after bevacizumab discontinuation.

PubMed

Zhuang, Hongqing; Yuan, Xiangkun; Chang, Joe Y; Song, Yongchun; Wang, Junjie; Yuan, Zhiyong; Wang, Xiaoguang; Wang, Ping

2016-07-26

The aim of the paper was to investigate the recurrence and its causes of radiation brain necrosis following bevacizumab discontinuation. This study included 14 patients with radiation brain necrosis (confirmed through imaging) after stereotactic radiotherapy for a primary or metastatic brain tumor and who received bevacizumab treatment from June 2011 through December 2014. The patients received bevacizumab at 5 mg/kg, q3-4w, for at least 3 cycles. The T1 signal intensity from enhanced MRI images was used as the evaluation criteria for the brain necrosis treatment efficacy. brain necrosis improved in 13 of the 14 cases (92.9%). However, during follow-up, 10 of the 13 responsive patients (76.9%) exhibited a recurrence in brain necrosis, and a multiple linear regression analysis shows that brain necrosis recurrence was related to the follow-up time after the initial bevacizumab treatment discontinuation. bevacizumab produced good short-term effects for radiation brain necrosis; however, most of the patients would recurrence after bevacizumab is discontinued. Thus, brain necrosis was irreversible.

Identification of fuel cycle simulator functionalities for analysis of transition to a new fuel cycle

DOE PAGES

Brown, Nicholas R.; Carlsen, Brett W.; Dixon, Brent W.; ...

2016-06-09

Dynamic fuel cycle simulation tools are intended to model holistic transient nuclear fuel cycle scenarios. As with all simulation tools, fuel cycle simulators require verification through unit tests, benchmark cases, and integral tests. Model validation is a vital aspect as well. Although compara-tive studies have been performed, there is no comprehensive unit test and benchmark library for fuel cycle simulator tools. The objective of this paper is to identify the must test functionalities of a fuel cycle simulator tool within the context of specific problems of interest to the Fuel Cycle Options Campaign within the U.S. Department of Energy smore » Office of Nuclear Energy. The approach in this paper identifies the features needed to cover the range of promising fuel cycle options identified in the DOE-NE Fuel Cycle Evaluation and Screening (E&S) and categorizes these features to facilitate prioritization. Features were categorized as essential functions, integrating features, and exemplary capabilities. One objective of this paper is to propose a library of unit tests applicable to each of the essential functions. Another underlying motivation for this paper is to encourage an international dialog on the functionalities and standard test methods for fuel cycle simulator tools.« less

High Power, Pulsed, RF Generation from Nonlinear Lumped Element Transmission Lines (NLETLs)

DTIC Science & Technology

2011-02-05

specific to solitons. including both overtaking and head on collision interactions and the Fermi- Pasta -Ulam recurrence phenomenon [50]. Contributions by...simulation has indicated the initiation of this curious effect. The Fernii- Pasta -Ulain recurrence phenomena, whereby a sinusoidal excitation applied to a

Freeze-Thaw Cycles and Soil Biogeochemistry: Implications for Greenhouse Gas emission

NASA Astrophysics Data System (ADS)

Rezanezhad, F.; Milojevic, T.; Oh, D. H.; Parsons, C. T.; Smeaton, C. M.; Van Cappellen, P.

2016-12-01

Freeze-thaw cycles represent a major natural climate forcing acting on soils at middle and high latitudes. Repeated freezing and thawing of soils changes their physical properties, geochemistry, and microbial community structure, which together govern the biogeochemical cycling of carbon and nutrients. In this presentation, we focus on how freeze-thaw cycles regulate carbon and nitrogen cycling and how these transformations influence greenhouse gas (GHG) fluxes. We present a novel approach, which combines the acquisition of physical and chemical data in a newly developed experimental soil column system. This system simulates realistic soil temperature profiles during freeze-thaw cycles. A high-resolution, Multi-Fiber Optode (MuFO) microsensor technique was used to detect oxygen (O2) continuously in the column at multiple depths. Surface and subsurface changes to gas and aqueous phase chemistry were measured to delineate the pathways and quantify soil respiration rates during freeze-thaw cycles. The results indicate that the time-dependent release of GHG from the soil surface is influenced by a combination of two key factors. Firstly, fluctuations in temperature and O2 availability affect soil biogeochemical activity and GHG production. Secondly, the recurrent development of a physical ice barrier prevents exchange of gaseous compounds between the soil and atmosphere during freezing conditions; removal of this barrier during thaw conditions increases GHG fluxes. During freezing, O2 levels in the unsaturated zone decreased due to restricted gas exchange with the atmosphere. As the soil thawed, O2 penetrated deeper into the soil enhancing the aerobic mineralization of organic carbon and nitrogen. Additionally, with the onset of thawing a pulse of gas flux occurred, which is attributed to the build-up of respiratory gases in the pore space during freezing. The latter implies enhanced anaerobic respiration as O2 supply ceases when the upper soil layer freezes.

Effect of freeze-thaw cycles on greenhouse gas fluxes from peat soils

NASA Astrophysics Data System (ADS)

Oh, H. D.; Rezanezhad, F.; Markelov, I.; McCarter, C. P. R.; Van Cappellen, P.

2017-12-01

The ongoing displacement of climate zones by global warming is increasing the frequency and intensity of freeze-thaw cycles in middle and high latitude regions, many of which are dominated by organic soils such as peat. Repeated freezing and thawing of soils changes their physical properties, geochemistry, and microbial community structure, which together govern the biogeochemical cycling of carbon and nutrients. In this presentation, we focus on how freeze-thaw cycles influence greenhouse gas fluxes from peat using a newly developed experimental soil column system that simulates realistic soil temperature profiles during freeze-thaw cycles. We measured the surface and subsurface changes to gas and aqueous phase chemistry to delineate the diffusion pathways and quantify soil greenhouse gas fluxes during freeze-thaw cycles using sulfur hexafluoride (SF6) as a conservative tracer. Three peat columns were assembled inside a temperature controlled chamber with different soil structures. All three columns were packed with 40 cm of undisturbed, slightly decomposed peat, where the soil of two columns had an additional 10 cm layer on top (one with loose Sphagnum moss and one with an impermeable plug). The results indicate that the release of SF6 and CO2 gas from the soil surface was influenced by the recurrent development of a physical ice barrier, which prevented gas exchange between the soil and atmosphere during freezing conditions. With the onset of thawing a pulse of SF6 and CO2 occurred, resulting in a flux of 3.24 and 2095.52 µmol/m2h, respectively, due to the build-up of gases in the liquid-phase pore space during freezing. Additionally, we developed a model to determine the specific diffusion coefficients for each peat column. These data allow us to better predict how increased frequency and intensity of freeze-thaw cycles will affect greenhouse gas emissions in northern peat soils.

The effect of simulator motion cues on initial training of airline pilots

DOT National Transportation Integrated Search

2005-08-15

Two earlier studies conducted in the framework of the Federal Aviation Administration/Volpe Flight Simulator Human Factors Program examining the effect of simulator motion on recurrent training and evaluation of airline pilots have found that in the ...

Statistical validation of a solar wind propagation model from 1 to 10 AU

NASA Astrophysics Data System (ADS)

Zieger, Bertalan; Hansen, Kenneth C.

2008-08-01

A one-dimensional (1-D) numerical magnetohydrodynamic (MHD) code is applied to propagate the solar wind from 1 AU through 10 AU, i.e., beyond the heliocentric distance of Saturn's orbit, in a non-rotating frame of reference. The time-varying boundary conditions at 1 AU are obtained from hourly solar wind data observed near the Earth. Although similar MHD simulations have been carried out and used by several authors, very little work has been done to validate the statistical accuracy of such solar wind predictions. In this paper, we present an extensive analysis of the prediction efficiency, using 12 selected years of solar wind data from the major heliospheric missions Pioneer, Voyager, and Ulysses. We map the numerical solution to each spacecraft in space and time, and validate the simulation, comparing the propagated solar wind parameters with in-situ observations. We do not restrict our statistical analysis to the times of spacecraft alignment, as most of the earlier case studies do. Our superposed epoch analysis suggests that the prediction efficiency is significantly higher during periods with high recurrence index of solar wind speed, typically in the late declining phase of the solar cycle. Among the solar wind variables, the solar wind speed can be predicted to the highest accuracy, with a linear correlation of 0.75 on average close to the time of opposition. We estimate the accuracy of shock arrival times to be as high as 10-15 hours within ±75 d from apparent opposition during years with high recurrence index. During solar activity maximum, there is a clear bias for the model to predicted shocks arriving later than observed in the data, suggesting that during these periods, there is an additional acceleration mechanism in the solar wind that is not included in the model.

Long-term Trends in Interplanetary Magnetic Field Strength and Solar Wind Structure during the 20th Century

NASA Technical Reports Server (NTRS)

Richardson, I. G.; Cliver, E. W.; Cane, H. V.; White, Nicholas E. (Technical Monitor)

2002-01-01

Lockwood et al have recently reported an approximately 40% increase in the radial component of the interplanetary magnetic field (IMF) at Earth between 1964 and 1996. We argue that this increase does not constitute a secular trend but is largely the consequence of lower than average fields during solar cycle 20 (1964-1976) in comparison with surrounding cycles. For times after 1976 the average IMF strength has actually decreased slightly. Examination of the cosmic ray intensity, an indirect measure of the IMF strength, over the last five solar cycles (19-23) also indicates that cycle averages of the IMF strength have been relatively constant since approximately 1954. We also consider the origin of the well-documented increase in the geomagnetic alphaalpha index that occurred primarily during the first half of the twentieth century. We surmise that the coronal mass ejection (CME) rate for recent solar cycles was approximately twice as high as that for solar cycles 100 years ago. However, this change in the CME rate and the accompanying increase in 27-day recurrent storm activity reported by others are unable to account completely for the increase in alphaalpha. Rather, the CMEs and recurrent high-speed streams at the beginning of the twentieth century must have been embedded in a background of slow solar wind that was less geoeffective (having, for example, lower IMF strength and/or flow speed) than its modern counterpart.

A Model for the Decrease in Amplitude of Carbon Isotope Excursions Throughout the Phanerozoic

NASA Astrophysics Data System (ADS)

Bachan, A.; Lau, K. V.; Saltzman, M.; Thomas, E.; Kump, L. R.; Payne, J.

2016-12-01

The geological cycling of carbon ties the ocean-­atmosphere carbon pool to Earth's biosphere and sedimentary reservoirs. Perturbations to this coupled system are recorded in the carbon-isotopic (δ13C) composition of marine carbonates. Large amplitude δ13C variations with durations of 0.5 - 10 m.y. are typically treated as individual events and interpreted accordingly. However, a recent compilation of Phanerozoic data reveals a decline in the variance of the δ13C record over time, suggesting a common underlying control. Here we propose that the redox structure of the continental shelves was a key determinant of the sensitivity of the geologic carbon cycle: when oxygen minimum zones (OMZs) were large, shallow, and prone to expansion, recurrent physical forcings (such as sea level and tectonics) would have had the capacity to drive large changes in the areal extent of OMZs, resulting in a strong leverage on δ13C values. Using a simple model of the geologic carbon cycle, we demonstrate that interactions between the carbon and phosphate cycles can result in amplification of recurrent forcings with periods in the 0.5 - 10 m.y. range. Thus, rather than requiring that physical forcings have their largest amplitude of variation on those time scales, enhanced sensitivity of the carbon cycle can account for the characteristic duration of δ13C excursions. Biologically mediated aspects of geologic carbon cycling, including the depth of bioturbation and evolution of pelagic calcifiers, likely drove a decline in the depth and extent of ocean anoxia over the Phanerozoic resulting in the stabilization of the geologic carbon cycle.

Incorporation of Carrier Phase Global Positioning System Measurements into the Navigation Reference System for Improved Performance

DTIC Science & Technology

1993-12-01

5-6 5.6.1 Large Cycle Slip Simulation ............................. 5-7 5.6.2 Small Cycle Slip Simulation ........................... 5-9...Appendix J. Small Cycle Slip Simulation Results ............................. J-1 Bibliography ........................................................ BIB-I...when subjected to large and small cycle slips. Results of the simulations indicate that the PNRS can provide an improved navigation solution over

Flight Simulator Motion Literature Pertinent to Airline-Pilot Recurrent Training and Evaluation.

DOT National Transportation Integrated Search

2011-08-08

There has been much debate over the years regarding the need for flight simulator motion for airline-pilot training and evaluation. From the intuitive perspective there is the dictum, The airplane moves, so the simulator must move but intui...

The content of recurrent dreams in young adolescents

PubMed Central

Gauchat, Aline; Séguin, Jean R.; McSween-Cadieux, Esther; Zadra, Antonio

2015-01-01

Studies on children’s recurrent dreams have been largely anecdotal and based on adults’ recollections of dreams experienced during childhood. We collected 102 reports of recurrent dreams from a sample of young adolescents aged between 11 and 15 years and scored the narratives using a range of content measures, including in relation to the threat simulation theory (TST) of dreaming. The most frequently reported themes involved confrontations with monsters or animals, followed by physical aggressions, falling and being chased. Recurrent dreams were more likely to include negative content elements than positive elements. Only half of the recurrent dreams contained threatening elements and their analysis provided mixed support for the TST. Differences between the content of recurrent dreams reported by young adolescent versus adults are discussed as are possible sex effects and key issues that remain to be addressed by future research. PMID:26366465

Estimation of Recurrence of Colorectal Adenomas with Dependent Censoring Using Weighted Logistic Regression

PubMed Central

Hsu, Chiu-Hsieh; Li, Yisheng; Long, Qi; Zhao, Qiuhong; Lance, Peter

2011-01-01

In colorectal polyp prevention trials, estimation of the rate of recurrence of adenomas at the end of the trial may be complicated by dependent censoring, that is, time to follow-up colonoscopy and dropout may be dependent on time to recurrence. Assuming that the auxiliary variables capture the dependence between recurrence and censoring times, we propose to fit two working models with the auxiliary variables as covariates to define risk groups and then extend an existing weighted logistic regression method for independent censoring to each risk group to accommodate potential dependent censoring. In a simulation study, we show that the proposed method results in both a gain in efficiency and reduction in bias for estimating the recurrence rate. We illustrate the methodology by analyzing a recurrent adenoma dataset from a colorectal polyp prevention trial. PMID:22065985

Hypofractionated Palliative Radiotherapy with Concurrent Radiosensitizing Chemotherapy for Advanced Head and Neck Cancer Using the "QUAD-SHOT Regimen".

PubMed

Gamez, Mauricio E; Agarwal, Manuj; Hu, Kenneth S; Lukens, John N; Harrison, Louis B

2017-02-01

To analyze the outcomes using the hypofractionated palliative radiotherapy regimen "QUAD-Shot" with concurrent radiosensitizing chemotherapy for advanced head and neck cancer. We analyzed twenty-one patients with newly-diagnosed or recurrent head and neck cancer treated with palliative hypofractionated concurrent chemoradiation using the QUAD-Shot regimen. All patients received at least one cycle of RT, with sixteen patients (76%) completing all three cycles. 85.7 % of patients had objective response to therapy with five patients (23.8%) demonstrating complete response (CR) and thirteen patients (61.9%) demonstrating partial response (PR). Palliation of symptoms was achieved in all (100%) of the sixteen patients that completed the three cycles. Median overall survival and median progression-free survival were 7 and 4 months, respectively. QUAD-Shot palliative radiation therapy coupled with radiosensitizing chemotherapy is efficacious and well-tolerated in patients with newly-diagnosed or recurrent head and neck cancer not amenable to curative therapy. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Segmented-memory recurrent neural networks.

PubMed

Chen, Jinmiao; Chaudhari, Narendra S

2009-08-01

Conventional recurrent neural networks (RNNs) have difficulties in learning long-term dependencies. To tackle this problem, we propose an architecture called segmented-memory recurrent neural network (SMRNN). A symbolic sequence is broken into segments and then presented as inputs to the SMRNN one symbol per cycle. The SMRNN uses separate internal states to store symbol-level context, as well as segment-level context. The symbol-level context is updated for each symbol presented for input. The segment-level context is updated after each segment. The SMRNN is trained using an extended real-time recurrent learning algorithm. We test the performance of SMRNN on the information latching problem, the "two-sequence problem" and the problem of protein secondary structure (PSS) prediction. Our implementation results indicate that SMRNN performs better on long-term dependency problems than conventional RNNs. Besides, we also theoretically analyze how the segmented memory of SMRNN helps learning long-term temporal dependencies and study the impact of the segment length.

Recurrent Activity in Radio Galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jamrozy, Marek; /Jagiellonian U.; Konar, Chiranjib

2007-10-15

One of the outstanding issues concerning extragalactic radio sources is the total duration of their active phase and the possible existence of duty cycles of their nuclear activity. A duty cycle can be recognized if there is a mechanism which preserves the information of past activity for a sufficiently long time after a new activity has started up. If a new cycle starts before the radio lobes created during a former activity period have faded, we can recognize this by the observations of a young radio source embedded in an old relic structure.

Tumour size is the only predictive factor of distant recurrence after pathological complete response to neoadjuvant chemotherapy in patients with large operable or locally advanced breast cancers: a sub-study of EORTC 10994/BIG 1-00 phase III trial.

PubMed

Fei, F; Messina, C; Slaets, L; Chakiba, C; Cameron, D; Bogaerts, J; Bonnefoi, H

2015-02-01

Although achieving a pathological complete response (pCR) after neoadjuvant chemotherapy (NACT) in breast cancer predicts a better outcome, some patients still relapse. The objectives of this study were to describe the types of events in this group of patients and to identify predictive factors for relapse. Patients with large operable or locally advanced breast cancers (T4d tumours were excluded) were randomised to receive either six cycles of anthracycline-based chemotherapy or three cycles of docetaxel followed by three cycles of eprirubicin/docetaxel. pCR was defined as no evidence of residual invasive cancer (or very few scattered tumour cells) in the primary tumour and axillary lymph nodes at surgery. Two Cox regression analyses were performed to identify predictive factors of relapse: one for recurrence-free interval (RFI) and one for distant recurrence-free interval (DRFI). Out of 283 eligible patients who achieved a pCR, 40 (14.1%) and 28 (9.9%) presented an event of interest for the RFI and DRFI analyses, respectively. Five-year RFI, DRFI and overall survival (OS) were 85.3% (95% confidence interval (CI), 80.1-89.3), 89.6% (95% CI, 85.0-92.9) and 91.9% (95% CI, 87.2-94.9), respectively. No predictors for RFI after pCR were identified. For DRFI, tumour size was the only predictor: Hazard ratio (HR) T3 versus T1-2=3.62 (95% CI, 1.66-7.89); HR T4 versus T1-2: HR, 2.80 (95% CI, 0.62-12.64) p=0.0048. In this study, clinical tumour size emerged as the only predictor for DRFI after pCR, with T3 and T4 tumours having an increased risk for distant recurrence compared to T1-2 tumours. Copyright © 2014 Elsevier Ltd. All rights reserved.

A phase I trial of intraperitoneal GEN-1, an IL-12 plasmid formulated with PEG-PEI-cholesterol lipopolymer, administered with pegylated liposomal doxorubicin in patients with recurrent or persistent epithelial ovarian, fallopian tube or primary peritoneal cancers: An NRG Oncology/Gynecologic Oncology Group study

PubMed Central

Thaker, Premal H.; Brady, William E.; Lankes, Heather A.; Odunsi, Kunle; Bradley, William H.; Moore, Kathleen N.; Muller, Carolyn Y.; Anwer, Khursheed; Schilder, Russell J.; Alvarez, Ronald D.; Fracasso, Paula M.

2017-01-01

Objective The study’s purpose was to assess safety and efficacy of escalating doses of weekly GEN-1 with pegylated liposomal doxorubicin (PLD) in patients with recurrent or persistent epithelial ovarian, fallopian tube or primary peritoneal cancers (EOC). Methods Patients had persistent or recurrent platinum-resistant EOC. The trial was a standard 3 + 3 phase I dose escalation design with patients receiving intravenous PLD 40 mg/m2 (dose level 1 and 2) or 50 mg/m2 (dose level 3) every 28 days and intraperitoneal GEN-1 at 24 mg/m2 (dose level 1) or 36 mg/m2 (dose level 2 and 3) on days 1, 8, 15, and 22 of a 28 day cycle. Cycles were repeated every 28 days until disease progression. Patients were monitored for toxicity, clinical efficacy, and evidence of systemic and intraperitoneal immunologic effect. Results Sixteen evaluable patients received a median of 4 cycles (range 1–8). No dose limiting toxicities were found. The adverse side effects were 4 grade 3 anemia, 2 grade 3 abdominal pain, 7 grade 3 neutropenia, and 2 grade 4 neutropenia. A clinical benefit of 57.1% (PR = 21.4%; SD = 35.7%) was found in the 14 patients with measurable disease. The highest number of partial responses (28.6%) and stable disease (57.1%) were found at dose level 3. The maximum tolerated dose was not reached. Increases in IL-12, IFN-γ, and TNF-α levels were found in peritoneal fluid following GEN-1 treatment. Conclusions GEN-1 in combination with PLD has encouraging clinical benefit and biological activity in recurrent or persistent EOC and warrants further investigation with escalating doses of GEN-1. PMID:28802766

Bevacizumab Plus Irinotecan in Recurrent WHO Grade 3 Malignant Gliomas

PubMed Central

Desjardins, Annick; Reardon, David A.; Herndon, James E.; Marcello, Jennifer; Quinn, Jennifer A.; Rich, Jeremy N.; Sathornsumetee, Sith; Gururangan, Sridharan; Sampson, John; Bailey, Leighann; Bigner, Darell D.; Friedman, Allan H.; Friedman, Henry S.; Vredenburgh, James J.

2013-01-01

Purpose Although patients with newly diagnosed WHO grade 3 malignant glioma have a more favorable prognosis than those with WHO grade 4 malignant glioma, salvage therapies following recurrence offer essentially palliative benefit. We did a phase II trial of bevacizumab, a monoclonal antibody to vascular endothelial growth factor, in combination with irinotecan for patients with recurrent grade 3 malignant glioma. Experimental Design Upon documentation of adequate safety among an initial cohort of nine patients treated with bevacizumab (10 mg/kg) and irinotecan every 14 days, a second cohort (n = 24) was treated with bevacizumab (15 mg/kg) every 3 weeks with irinotecan on days 1, 8, 22, and 29 of each 42-day cycle. For both cohorts, the dose of irinotecan was 340 mg/m2 for patients on enzyme-inducing antiepileptic drugs (EIAED) and 125 mg/m2 for patients not on EIAEDs. After each 6-week cycle, patients were evaluated with a physical examination and magnetic resonance imaging. Results The 6-month progression-free survival was 55% (95% confidence interval, 36–70%). The 6-month overall survival was 79% (95% confidence interval, 61–89%). Twenty patients (61%) had at least a partial response. Outcome did not differ between the two treatment cohorts. Significant adverse events were infrequent and included a central nervous system hemorrhage in one patient, and one patient who developed thrombotic thrombocytopenic purpura. Conclusion Bevacizumab and irinotecan is an active regimen with acceptable toxicity for patients with recurrent WHO grade 3 malignant glioma. PMID:18981004

Endometrial protein PP14 and CA-125 in recurrent miscarriage patients; correlation with pregnancy outcome.

PubMed

Dalton, C F; Laird, S M; Estdale, S E; Saravelos, H G; Li, T C

1998-11-01

The concentrations of endometrial proteins PP14 and CA-125 were measured in uterine flushings taken on days LH+10 and LH+12 (10 and 12 days after luteinizing hormone surge) of the menstrual cycle from 15 normal, fertile women and 49 women who suffered recurrent miscarriage. The concentration of PP14 was significantly lower in the flushings from the recurrent miscarriage patients than in those from fertile controls on both day LH+10 (median: 1300, range: 3-10 300 ng/ml versus median: 13 933, range: 2174-40 404 ng/ml; P < 0.01) and LH+12 (median: 1560, range: 820-12 100 ng/ml versus median: 14 047, range 1402-62 108 ng/ml; P < 0.05). Similarly concentrations of CA-125 were significantly lower in flushings from recurrent miscarriage women compared to controls on both day LH + 10 (median: 1555, range: 47-6710 U/ml versus median: 6385.5, range 2884-27 731 U/ml, P < 0.01) and LH+12 (median: 2892, range: 956-9974 U/ml versus median: 7127.5, range: 1591-21 343 U/ml; P < 0.05). In contrast there was no significant difference in the concentration of PP14 in plasma samples taken on the same days as the flushings from recurrent miscarriage patients and fertile controls. The concentrations of PP14 in uterine flushings obtained on day LH + 10 or LH + 12 from recurrent miscarriage women during a pre-pregnancy investigative cycle were significantly lower (P < 0.05) in patients who went on to miscarry (median: 1000, range: 9-2900 ng/ml) than those who went on to have a live birth (median: 1440, range: 4-12 100 ng/ml) during a subsequent pregnancy. In contrast there was no significant difference in uterine CA-125 or plasma PP14 concentrations between these two groups of recurrent miscarriage patients. The results suggest that measurements of uterine PP14 and CA-125 may be useful in the assessment of endometrial development in recurrent miscarriage patients and suggest the importance of PP14 in preparing the endometrium for embryo implantation. In addition pre-pregnancy uterine PP14 measurements may be useful in predicting subsequent pregnancy outcome.

Bayesian Design of Superiority Clinical Trials for Recurrent Events Data with Applications to Bleeding and Transfusion Events in Myelodyplastic Syndrome

PubMed Central

Chen, Ming-Hui; Zeng, Donglin; Hu, Kuolung; Jia, Catherine

2014-01-01

Summary In many biomedical studies, patients may experience the same type of recurrent event repeatedly over time, such as bleeding, multiple infections and disease. In this article, we propose a Bayesian design to a pivotal clinical trial in which lower risk myelodysplastic syndromes (MDS) patients are treated with MDS disease modifying therapies. One of the key study objectives is to demonstrate the investigational product (treatment) effect on reduction of platelet transfusion and bleeding events while receiving MDS therapies. In this context, we propose a new Bayesian approach for the design of superiority clinical trials using recurrent events frailty regression models. Historical recurrent events data from an already completed phase 2 trial are incorporated into the Bayesian design via the partial borrowing power prior of Ibrahim et al. (2012, Biometrics 68, 578–586). An efficient Gibbs sampling algorithm, a predictive data generation algorithm, and a simulation-based algorithm are developed for sampling from the fitting posterior distribution, generating the predictive recurrent events data, and computing various design quantities such as the type I error rate and power, respectively. An extensive simulation study is conducted to compare the proposed method to the existing frequentist methods and to investigate various operating characteristics of the proposed design. PMID:25041037

Machine learning in sentiment reconstruction of the simulated stock market

NASA Astrophysics Data System (ADS)

Goykhman, Mikhail; Teimouri, Ali

2018-02-01

In this paper we continue the study of the simulated stock market framework defined by the driving sentiment processes. We focus on the market environment driven by the buy/sell trading sentiment process of the Markov chain type. We apply the methodology of the Hidden Markov Models and the Recurrent Neural Networks to reconstruct the transition probabilities matrix of the Markov sentiment process and recover the underlying sentiment states from the observed stock price behavior. We demonstrate that the Hidden Markov Model can successfully recover the transition probabilities matrix for the hidden sentiment process of the Markov Chain type. We also demonstrate that the Recurrent Neural Network can successfully recover the hidden sentiment states from the observed simulated stock price time series.

The content of recurrent dreams in young adolescents.

PubMed

Gauchat, Aline; Séguin, Jean R; McSween-Cadieux, Esther; Zadra, Antonio

2015-12-01

Studies on children's recurrent dreams have been largely anecdotal and based on adults' recollections of dreams experienced during childhood. We collected 102 reports of recurrent dreams from a sample of young adolescents aged between 11 and 15years and scored the narratives using a range of content measures, including in relation to the threat simulation theory (TST) of dreaming. The most frequently reported themes involved confrontations with monsters or animals, followed by physical aggressions, falling and being chased. Recurrent dreams were more likely to include negative content elements than positive elements. Only half of the recurrent dreams contained threatening elements and their analysis provided mixed support for the TST. Differences between the content of recurrent dreams reported by young adolescent versus adults are discussed as are possible sex effects and key issues that remain to be addressed by future research. Copyright © 2015 Elsevier Inc. All rights reserved.

A model-free characterization of recurrences in stationary time series

NASA Astrophysics Data System (ADS)

Chicheportiche, Rémy; Chakraborti, Anirban

2017-05-01

Study of recurrences in earthquakes, climate, financial time-series, etc. is crucial to better forecast disasters and limit their consequences. Most of the previous phenomenological studies of recurrences have involved only a long-ranged autocorrelation function, and ignored the multi-scaling properties induced by potential higher order dependencies. We argue that copulas is a natural model-free framework to study non-linear dependencies in time series and related concepts like recurrences. Consequently, we arrive at the facts that (i) non-linear dependences do impact both the statistics and dynamics of recurrence times, and (ii) the scaling arguments for the unconditional distribution may not be applicable. Hence, fitting and/or simulating the intertemporal distribution of recurrence intervals is very much system specific, and cannot actually benefit from universal features, in contrast to the previous claims. This has important implications in epilepsy prognosis and financial risk management applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Nicholas R.; Carlsen, Brett W.; Dixon, Brent W.

Dynamic fuel cycle simulation tools are intended to model holistic transient nuclear fuel cycle scenarios. As with all simulation tools, fuel cycle simulators require verification through unit tests, benchmark cases, and integral tests. Model validation is a vital aspect as well. Although compara-tive studies have been performed, there is no comprehensive unit test and benchmark library for fuel cycle simulator tools. The objective of this paper is to identify the must test functionalities of a fuel cycle simulator tool within the context of specific problems of interest to the Fuel Cycle Options Campaign within the U.S. Department of Energy smore » Office of Nuclear Energy. The approach in this paper identifies the features needed to cover the range of promising fuel cycle options identified in the DOE-NE Fuel Cycle Evaluation and Screening (E&S) and categorizes these features to facilitate prioritization. Features were categorized as essential functions, integrating features, and exemplary capabilities. One objective of this paper is to propose a library of unit tests applicable to each of the essential functions. Another underlying motivation for this paper is to encourage an international dialog on the functionalities and standard test methods for fuel cycle simulator tools.« less

Endogenously determined cycles: empirical evidence from livestock industries.

PubMed

McCullough, Michael P; Huffaker, Ray; Marsh, Thomas L

2012-04-01

This paper applies the techniques of phase space reconstruction and recurrence quantification analysis to investigate U.S. livestock cycles in relation to recent literature on the business cycle. Results are presented for pork and cattle cycles, providing empirical evidence that the cycles themselves have slowly diminished. By comparing the evolution of production processes for the two livestock cycles we argue that the major cause for this moderation is largely endogenous. The analysis suggests that previous theoretical models relying solely on exogenous shocks to create cyclical patterns do not fully capture changes in system dynamics. Specifically, the biological constraint in livestock dynamics has become less significant while technology and information are relatively more significant. Concurrently, vertical integration of the supply chain may have improved inventory management, all resulting in a small, less deterministic, cyclical effect.

Low-dimensional recurrent neural network-based Kalman filter for speech enhancement.

PubMed

Xia, Youshen; Wang, Jun

2015-07-01

This paper proposes a new recurrent neural network-based Kalman filter for speech enhancement, based on a noise-constrained least squares estimate. The parameters of speech signal modeled as autoregressive process are first estimated by using the proposed recurrent neural network and the speech signal is then recovered from Kalman filtering. The proposed recurrent neural network is globally asymptomatically stable to the noise-constrained estimate. Because the noise-constrained estimate has a robust performance against non-Gaussian noise, the proposed recurrent neural network-based speech enhancement algorithm can minimize the estimation error of Kalman filter parameters in non-Gaussian noise. Furthermore, having a low-dimensional model feature, the proposed neural network-based speech enhancement algorithm has a much faster speed than two existing recurrent neural networks-based speech enhancement algorithms. Simulation results show that the proposed recurrent neural network-based speech enhancement algorithm can produce a good performance with fast computation and noise reduction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modulation Instability and Phase-Shifted Fermi-Pasta-Ulam Recurrence

PubMed Central

Kimmoun, O.; Hsu, H. C.; Branger, H.; Li, M. S.; Chen, Y. Y.; Kharif, C.; Onorato, M.; Kelleher, E. J. R.; Kibler, B.; Akhmediev, N.; Chabchoub, A.

2016-01-01

Instabilities are common phenomena frequently observed in nature, sometimes leading to unexpected catastrophes and disasters in seemingly normal conditions. One prominent form of instability in a distributed system is its response to a harmonic modulation. Such instability has special names in various branches of physics and is generally known as modulation instability (MI). The MI leads to a growth-decay cycle of unstable waves and is therefore related to Fermi-Pasta-Ulam (FPU) recurrence since breather solutions of the nonlinear Schrödinger equation (NLSE) are known to accurately describe growth and decay of modulationally unstable waves in conservative systems. Here, we report theoretical, numerical and experimental evidence of the effect of dissipation on FPU cycles in a super wave tank, namely their shift in a determined order. In showing that ideal NLSE breather solutions can describe such dissipative nonlinear dynamics, our results may impact the interpretation of a wide range of new physics scenarios. PMID:27436005

Effects of acoustic waves on stick-slip in granular media and implications for earthquakes

USGS Publications Warehouse

Johnson, P.A.; Savage, H.; Knuth, M.; Gomberg, J.; Marone, Chris

2008-01-01

It remains unknown how the small strains induced by seismic waves can trigger earthquakes at large distances, in some cases thousands of kilometres from the triggering earthquake, with failure often occurring long after the waves have passed. Earthquake nucleation is usually observed to take place at depths of 10-20 km, and so static overburden should be large enough to inhibit triggering by seismic-wave stress perturbations. To understand the physics of dynamic triggering better, as well as the influence of dynamic stressing on earthquake recurrence, we have conducted laboratory studies of stick-slip in granular media with and without applied acoustic vibration. Glass beads were used to simulate granular fault zone material, sheared under constant normal stress, and subject to transient or continuous perturbation by acoustic waves. Here we show that small-magnitude failure events, corresponding to triggered aftershocks, occur when applied sound-wave amplitudes exceed several microstrain. These events are frequently delayed or occur as part of a cascade of small events. Vibrations also cause large slip events to be disrupted in time relative to those without wave perturbation. The effects are observed for many large-event cycles after vibrations cease, indicating a strain memory in the granular material. Dynamic stressing of tectonic faults may play a similar role in determining the complexity of earthquake recurrence. ??2007 Nature Publishing Group.

Modelling volatility recurrence intervals in the Chinese commodity futures market

NASA Astrophysics Data System (ADS)

Zhou, Weijie; Wang, Zhengxin; Guo, Haiming

2016-09-01

The law of extreme event occurrence attracts much research. The volatility recurrence intervals of Chinese commodity futures market prices are studied: the results show that the probability distributions of the scaled volatility recurrence intervals have a uniform scaling curve for different thresholds q. So we can deduce the probability distribution of extreme events from normal events. The tail of a scaling curve can be well fitted by a Weibull form, which is significance-tested by KS measures. Both short-term and long-term memories are present in the recurrence intervals with different thresholds q, which denotes that the recurrence intervals can be predicted. In addition, similar to volatility, volatility recurrence intervals also have clustering features. Through Monte Carlo simulation, we artificially synthesise ARMA, GARCH-class sequences similar to the original data, and find out the reason behind the clustering. The larger the parameter d of the FIGARCH model, the stronger the clustering effect is. Finally, we use the Fractionally Integrated Autoregressive Conditional Duration model (FIACD) to analyse the recurrence interval characteristics. The results indicated that the FIACD model may provide a method to analyse volatility recurrence intervals.

Exploration of the recurrence in radiation brain necrosis after bevacizumab discontinuation

PubMed Central

Zhuang, Hongqing; Yuan, Xiangkun; Chang, Joe Y.; Song, Yongchun; Wang, Junjie; Yuan, Zhiyong; Wang, Xiaoguang; Wang, Ping

2016-01-01

Objective: The aim of the paper was to investigate the recurrence and its causes of radiation brain necrosis following bevacizumab discontinuation. Methods: This study included 14 patients with radiation brain necrosis (confirmed through imaging) after stereotactic radiotherapy for a primary or metastatic brain tumor and who received bevacizumab treatment from June 2011 through December 2014. The patients received bevacizumab at 5 mg/kg, q3-4w, for at least 3 cycles. The T1 signal intensity from enhanced MRI images was used as the evaluation criteria for the brain necrosis treatment efficacy. Results: brain necrosis improved in 13 of the 14 cases (92.9%). However, during follow-up, 10 of the 13 responsive patients (76.9%) exhibited a recurrence in brain necrosis, and a multiple linear regression analysis shows that brain necrosis recurrence was related to the follow-up time after the initial bevacizumab treatment discontinuation. Conclusion: bevacizumab produced good short-term effects for radiation brain necrosis; however, most of the patients would recurrence after bevacizumab is discontinued. Thus, brain necrosis was irreversible. PMID:26934327

Cost-Effectiveness Analysis of Five Competing Strategies for the Management of Multiple Recurrent Community-Onset Clostridium difficile Infection in France

PubMed Central

Galperine, Tatiana; Denies, Fanette; Lannoy, Damien; Lenne, Xavier; Odou, Pascal; Guery, Benoit; Dervaux, Benoit

2017-01-01

Background Clostridium difficile infection (CDI) is characterized by high rates of recurrence, resulting in substantial health care costs. The aim of this study was to analyze the cost-effectiveness of treatments for the management of second recurrence of community-onset CDI in France. Methods We developed a decision-analytic simulation model to compare 5 treatments for the management of second recurrence of community-onset CDI: pulsed-tapered vancomycin, fidaxomicin, fecal microbiota transplantation (FMT) via colonoscopy, FMT via duodenal infusion, and FMT via enema. The model outcome was the incremental cost-effectiveness ratio (ICER), expressed as cost per quality-adjusted life year (QALY) among the 5 treatments. ICERs were interpreted using a willingness-to-pay threshold of €32,000/QALY. Uncertainty was evaluated through deterministic and probabilistic sensitivity analyses. Results Three strategies were on the efficiency frontier: pulsed-tapered vancomycin, FMT via enema, and FMT via colonoscopy, in order of increasing effectiveness. FMT via duodenal infusion and fidaxomicin were dominated (i.e. less effective and costlier) by FMT via colonoscopy and FMT via enema. FMT via enema compared with pulsed-tapered vancomycin had an ICER of €18,092/QALY. The ICER for FMT via colonoscopy versus FMT via enema was €73,653/QALY. Probabilistic sensitivity analysis with 10,000 Monte Carlo simulations showed that FMT via enema was the most cost-effective strategy in 58% of simulations and FMT via colonoscopy was favored in 19% at a willingness-to-pay threshold of €32,000/QALY. Conclusions FMT via enema is the most cost-effective initial strategy for the management of second recurrence of community-onset CDI at a willingness-to-pay threshold of €32,000/QALY. PMID:28103289

Cost-Effectiveness Analysis of Five Competing Strategies for the Management of Multiple Recurrent Community-Onset Clostridium difficile Infection in France.

PubMed

Baro, Emilie; Galperine, Tatiana; Denies, Fanette; Lannoy, Damien; Lenne, Xavier; Odou, Pascal; Guery, Benoit; Dervaux, Benoit

2017-01-01

Clostridium difficile infection (CDI) is characterized by high rates of recurrence, resulting in substantial health care costs. The aim of this study was to analyze the cost-effectiveness of treatments for the management of second recurrence of community-onset CDI in France. We developed a decision-analytic simulation model to compare 5 treatments for the management of second recurrence of community-onset CDI: pulsed-tapered vancomycin, fidaxomicin, fecal microbiota transplantation (FMT) via colonoscopy, FMT via duodenal infusion, and FMT via enema. The model outcome was the incremental cost-effectiveness ratio (ICER), expressed as cost per quality-adjusted life year (QALY) among the 5 treatments. ICERs were interpreted using a willingness-to-pay threshold of €32,000/QALY. Uncertainty was evaluated through deterministic and probabilistic sensitivity analyses. Three strategies were on the efficiency frontier: pulsed-tapered vancomycin, FMT via enema, and FMT via colonoscopy, in order of increasing effectiveness. FMT via duodenal infusion and fidaxomicin were dominated (i.e. less effective and costlier) by FMT via colonoscopy and FMT via enema. FMT via enema compared with pulsed-tapered vancomycin had an ICER of €18,092/QALY. The ICER for FMT via colonoscopy versus FMT via enema was €73,653/QALY. Probabilistic sensitivity analysis with 10,000 Monte Carlo simulations showed that FMT via enema was the most cost-effective strategy in 58% of simulations and FMT via colonoscopy was favored in 19% at a willingness-to-pay threshold of €32,000/QALY. FMT via enema is the most cost-effective initial strategy for the management of second recurrence of community-onset CDI at a willingness-to-pay threshold of €32,000/QALY.

Coseismic slip on the southern Cascadia megathrust implied by tsunami deposits in an Oregon lake and earthquake-triggered marine turbidites

NASA Astrophysics Data System (ADS)

Witter, Robert C.; Zhang, Yinglong; Wang, Kelin; Goldfinger, Chris; Priest, George R.; Allan, Jonathan C.

2012-10-01

We test hypothetical tsunami scenarios against a 4,600-year record of sandy deposits in a southern Oregon coastal lake that offer minimum inundation limits for prehistoric Cascadia tsunamis. Tsunami simulations constrain coseismic slip estimates for the southern Cascadia megathrust and contrast with slip deficits implied by earthquake recurrence intervals from turbidite paleoseismology. We model the tsunamigenic seafloor deformation using a three-dimensional elastic dislocation model and test three Cascadia earthquake rupture scenarios: slip partitioned to a splay fault; slip distributed symmetrically on the megathrust; and slip skewed seaward. Numerical tsunami simulations use the hydrodynamic finite element model, SELFE, that solves nonlinear shallow-water wave equations on unstructured grids. Our simulations of the 1700 Cascadia tsunami require >12-13 m of peak slip on the southern Cascadia megathrust offshore southern Oregon. The simulations account for tidal and shoreline variability and must crest the ˜6-m-high lake outlet to satisfy geological evidence of inundation. Accumulating this slip deficit requires ≥360-400 years at the plate convergence rate, exceeding the 330-year span of two earthquake cycles preceding 1700. Predecessors of the 1700 earthquake likely involved >8-9 m of coseismic slip accrued over >260 years. Simple slip budgets constrained by tsunami simulations allow an average of 5.2 m of slip per event for 11 additional earthquakes inferred from the southern Cascadia turbidite record. By comparison, slip deficits inferred from time intervals separating earthquake-triggered turbidites are poor predictors of coseismic slip because they meet geological constraints for only 4 out of 12 (˜33%) Cascadia tsunamis.

Nitrogen and Phosphorus Budgets in the Northwestern Mediterranean Deep Convection Region

NASA Astrophysics Data System (ADS)

Kessouri, Faycal; Ulses, Caroline; Estournel, Claude; Marsaleix, Patrick; Severin, Tatiana; Pujo-Pay, Mireille; Caparros, Jocelyne; Raimbault, Patrick; Pasqueron de Fommervault, Orens; D'Ortenzio, Fabrizio; Taillandier, Vincent; Testor, Pierre; Conan, Pascal

2017-12-01

The aim of this study is to understand the biogeochemical cycles of the northwestern Mediterranean Sea (NW Med), where a recurrent spring bloom related to dense water formation occurs. We used a coupled physical-biogeochemical model at high resolution to simulate realistic 1 year period and analyze the nitrogen (N) and phosphorus (P) cycles. First, the model was evaluated using cruises carried out in winter, spring, and summer and a Bio-Argo float deployed in spring. Then, the annual cycle of meteorological and hydrodynamical forcing and nutrients stocks in the upper layer were analyzed. Third, the effect of biogeochemical and physical processes on N and P was quantified. Fourth, we quantified the effects of the physical and biological processes on the seasonal changes of the molar NO3:PO4 ratio, particularly high compared to the global ocean. The deep convection reduced the NO3:PO4 ratio of upper waters, but consumption by phytoplankton increased it. Finally, N and P budgets were estimated. At the annual scale, this area constituted a sink of inorganic and a source of organic N and P for the peripheral area. NO3 and PO4 were horizontally advected from the peripheral regions into the intermediate waters (130-800 m) of the deep convection area, while organic matter was exported throughout the whole water column toward the surrounding areas. The annual budget suggests that the NW Med deep convection constitutes a major source of nutrients for the photic zone of the Mediterranean Sea.

Second-line chemotherapy with dacarbazine and fotemustine in nitrosourea-pretreated patients with recurrent glioblastoma multiforme.

PubMed

Fazeny-Dörner, Barbara; Veitl, Mario; Wenzel, Catharina; Piribauer, Maria; Rössler, Karl; Dieckmann, Karin; Ungersböck, Karl; Marosi, Christine

2003-07-01

The aim of this study was to assess the efficacy and toxicity of a combination of dacarbazine (D) and fotemustine (F) administered to a homogenous group of patients with recurrent or progressive glioblastoma multiforme (GBM). Thirty-one patients with computed tomography or magnetic resonance imaging scan evidence of recurrent or progressive GBM after first-line chemotherapy with nitrosoureas as well as radiation therapy were given a combination of D (200 mg/m2) and F (100 mg/m2). At 30 min after termination of D administration, F was given over 60 min. Treatment was performed in an outpatient setting every 21 days. A total of 140 cycles (range 1-12 cycles; median 4 cycles) was administered. One partial response (3%) lasting for 11 weeks was observed. Sixteen (52%) patients reached stable disease lasting between 7 and 94 weeks. Median survival from start of the D/F combination was 45 (range 10-150) weeks. Median time to progression was 17 (3-101) weeks for all patients. Major toxicity was myelosuppression resulting in exclusion from study in seven (23%) patients [due to thrombocytopenia common toxicity criteria (CTC) grade 2 persisting longer than 3 weeks in three patients, due to thrombocytopenia CTC grade >/=3 in three and due to leukopenia CTC grade 3 in one patient]. No other toxicity than alopecia occurred. We conclude that the D/F combination is a well-tolerated second-line regimen and can be administered in a complete outpatient setting. D/F shows efficacy even in nitrosourea-pretreated patients and justifies further investigation.

Simulate earthquake cycles on the oceanic transform faults in the framework of rate-and-state friction

NASA Astrophysics Data System (ADS)

Wei, M.

2016-12-01

Progress towards a quantitative and predictive understanding of the earthquake behavior can be achieved by improved understanding of earthquake cycles. However, it is hindered by the long repeat times (100s to 1000s of years) of the largest earthquakes on most faults. At fast-spreading oceanic transform faults, the typical repeating time ranges from 5-20 years, making them a unique tectonic environment for studying the earthquake cycle. One important observation on OTFs is the quasi-periodicity and the spatial-temporal clustering of large earthquakes: same fault segment ruptured repeatedly at a near constant interval and nearby segments ruptured during a short time period. This has been observed on the Gofar and Discovery faults in the East Pacific Rise. Between 1992 and 2014, five clusters of M6 earthquakes occurred on the Gofar and Discovery fault system with recurrence intervals of 4-6 years. Each cluster consisted of a westward migration of seismicity from the Discovery to Gofar segment within a 2-year period, providing strong evidence for spatial-temporal clustering of large OTFs earthquakes. I simulated earthquake cycles of oceanic transform fault in the framework of rate-and-state friction, motivated by the observations at the Gofar and Discovery faults. I focus on a model with two seismic segments, each 20 km long and 5 km wide, separated by an aseismic segment of 10 km wide. This geometry is set based on aftershock locations of the 2008 M6.0 earthquake on Gofar. The repeating large earthquake on both segments are reproduced with similar magnitude as observed. I set the state parameter differently for the two seismic segments so initially they are not synchornized. Results also show that synchronization of the two seismic patches can be achieved after several earthquake cycles when the effective normal stress or the a-b parameter is smaller than surrounding aseismic areas, both having reduced the resistance to seismic rupture in the VS segment. These parameter settings likely reflect the alteration of stress and friction property by the enhanced hydrothermal activity suggested by McGuire et al., 2012. The seismic coupling ratio of the entire model is about 0.3, not far from the global average of 0.15.

Recurrent hemorrhage from corpus luteum during anticoagulant therapy.

PubMed Central

Wong, K. P.; Gillett, P. G.

1977-01-01

A 43-year old woman had recurrent massive intraperitoneal hemorrhage from rupture of a hemorrhagic corpus luteum in two successive menstrual cycles while receiving anticoagulant therapy. Left oophorectomy was performed on the first occasion and right salpingo-oophorectomy with left salpingectomy on the second. While the precise incidence cannot be determined, rupture from a hemorrhagic corpus luteum appears to be a rare but potentially catastrophic complication of anticoagulant therapy. Hence possible ovarian hemorrhage should be considered in women of reproductive age receiving heparin or sodium warfarin therapy. PMID:844024

VR-simulation cataract surgery in non-experienced trainees: evolution of surgical skill

NASA Astrophysics Data System (ADS)

Söderberg, Per; Erngrund, Markus; Skarman, Eva; Nordh, Leif; Laurell, Carl-Gustaf

2011-03-01

Conclusion: The current data imply that the performance index as defined herein is a valid measure of the performance of a trainee using the virtual reality phacoemulsification simulator. Further, the performance index increase linearly with measurement cycles for less than five measurement cycles. To fully use the learning potential of the simulator more than four measurement cycles are required. Materials and methods: Altogether, 10 trainees were introduced to the simulator by an instructor and then performed a training program including four measurement cycles with three iterated measurements of the simulation at the end of each cycle. The simulation characteristics was standardized and defined in 14 parameters. The simulation was measured separately for the sculpting phase in 21 variables, and for the evacuation phase in 22 variables. A performance index based on all measured variables was estimated for the sculpting phase and the evacuation phase, respectively, for each measurement and the three measurements for each cycle were averaged. Finally, the performance as a function of measurement cycle was estimated for each trainee with regression, assuming a straight line. The estimated intercept and inclination coefficients, respectively, were finally averaged for all trainees. Results: The performance increased linearly with the number of measurement cycles both for the sculpting and for the evacuation phase.

Computational Modeling of Statistical Learning: Effects of Transitional Probability versus Frequency and Links to Word Learning

ERIC Educational Resources Information Center

Mirman, Daniel; Estes, Katharine Graf; Magnuson, James S.

2010-01-01

Statistical learning mechanisms play an important role in theories of language acquisition and processing. Recurrent neural network models have provided important insights into how these mechanisms might operate. We examined whether such networks capture two key findings in human statistical learning. In Simulation 1, a simple recurrent network…

Hemispheric Coupling: Comparing Dynamo Simulations and Observations

NASA Astrophysics Data System (ADS)

Norton, A. A.; Charbonneau, P.; Passos, D.

2014-12-01

Numerical simulations that reproduce solar-like magnetic cycles can be used to generate long-term statistics. The variations in north-south hemispheric solar cycle synchronicity and amplitude produced in simulations has not been widely compared to observations. The observed limits on solar cycle amplitude and phase asymmetry show that hemispheric sunspot area production is no more than 20 % asymmetric for cycles 17-23 and that phase lags do not exceed 20 % (or two years) of the total cycle period, as determined from Royal Greenwich Observatory sunspot data. Several independent studies have found a long-term trend in phase values as one hemisphere leads the other for, on average, four cycles. Such persistence in phase is not indicative of a stochastic phenomenon. We compare these observational findings to the magnetic cycle found in a numerical simulation of solar convection recently produced with the EULAG-MHD model. This long "millennium simulation" spans more than 1600 years and generated 40 regular, sunspot-like cycles. While the simulated cycle length is too long (˜40 yrs) and the toroidal bands remain at too high of latitudes (>30°), some solar-like aspects of hemispheric asymmetry are reproduced. The model is successful at reproducing the synchrony of polarity inversions and onset of cycle as the simulated phase lags do not exceed 20 % of the cycle period. The simulated amplitude variations between the north and south hemispheres are larger than those observed in the Sun, some up to 40 %. An interesting note is that the simulations also show that one hemisphere can persistently lead the other for several successive cycles, placing an upper bound on the efficiency of transequatorial magnetic coupling mechanisms. These include magnetic diffusion, cross-equatorial mixing within latitudinally-elongated convective rolls (a.k.a. "banana cells") and transequatorial meridional flow cells. One or more of these processes may lead to magnetic flux cancellation whereby the oppositely directed fields come in close proximity and cancel each other across the magnetic equator late in the solar cycle. We discuss the discrepancies between model and observations and the constraints they pose on possible mechanisms of hemispheric coupling.

Optimizing Adjuvant Therapy for Resected Pancreatic Cancer

Cancer.gov

In this clinical trial, patients with resected pancreatic head cancer will be randomly assigned to receive either gemcitabine with or without erlotinib for 5 treatment cycles. Patients who do not experience disease progression or recurrence will then be r

PRELIMINARY RESULTS OF A PROSPECTIVE FEASIBILITY PILOT STUDY OF “GEMPOX” (GEMCITABINE, OXALIPLATIN, AND PACLITAXEL) IN PEDIATRIC AND ADULT PATIENTS WITH REFRACTORY OR RECURRENT CENTRAL NERVOUS SYSTEM (CNS) GERM CELL TUMORS (GCT): THE INTERNATIONAL CNS GCT CONSORTIUM TRIAL, CNS GCT-4

PubMed Central

Finlay, Jonathan L.; Liu, Yin; Haley, Kelley; Erdreich-Epstein, Anat; Rushing, Teresa; Grimm, John; Wong, Kenneth E.; Kiehna, Erin; Krieger, Mark D.; Gilles, Floyd; Badie, Benham; D'Apuzzo, Massimo; Dhall, Girish

2014-01-01

BACKGROUND: The optimal management of patients with recurrent CNS GCT, especially those with non-germinomatous (mixed malignant) GCT (MMGCT), remains unclear. Preliminary results are presented on the response rate, toxicity and early outcomes of a re-induction regimen of gemcitabine, oxaliplatin and paclitaxel (GEMPOX) administered, in responsive patients, prior to myeloablative chemotherapy and autologous hematopoietic cell rescue (HDCx + AuHCR). METHODS: Since December 2004, 13 recurrent or refractory patients (12 MMGCT, 1 germinoma; 12 males; mean age 16.5 years, range 7-34 years) have been treated with up to 4 cycles of gemcitabine (800 mg/m2), oxaliplatin (100 mg/m2) and paclitaxel (170 mg/m2), administered on one day at 14 days intervals. RESULTS: Of 13 patients, five were treated on a preceding feasibility pilot with 1-3 cycles of GEMPOX, and seven have been formally enrolled on an ongoing prospective multi-center trial. Six patients achieved complete remissions (tumor marker and/or imaging studies), five achieved partial remissions and two developed progressive disease (PD) while on GEMPOX; one patient with PD after 1 cycle had pathologically confirmed malignant transformation to pure embryonal rhabdomyosarcoma.; the second patient, with pure pineal choriocarcinoma, progressed following the second cycle of GEMPOX. Eleven of the 13 patents subsequently underwent HDCx + AuHCR. Six of them subsequently received irradiation. Transient hepatotoxicity and pancytopenia were the most commonly observed toxicities. Other toxicities included: paclitaxel anaphylaxis (1), transient encephalopathy (1), peripheral neuropathy (1), hyperesthesia (4), mucositis (2) and electrolyte imbalances (3). Four of the 12 patients with MMGCT continue alive and disease-free for 8+ , 10+ , 14+ and 16+ months since discontinuation of all therapy. One patient (with pure yolk sac tumor) relapsed in a loco-regional extra-CNS location (cavernous and ethmoid/sphenoid sinuses) and remains alive with progressive disease on therapy now 12+ months post-HDCx + AuHCR. CONCLUSIONS: GEMPOX appears to be an effective re-induction regimen for patients with recurrent CNS MMGCT, with acceptable toxicities. The ongoing multi-center, international trial should confirm this and demonstrate the contribution of GEMPOX towards improved survival when followed by HDCx + AuHCR with or without further irradiation, in the setting of minimal residual disease. SECONDARY CATEGORY: Pediatrics.

Laboratory constraints on models of earthquake recurrence

NASA Astrophysics Data System (ADS)

Beeler, N. M.; Tullis, Terry; Junger, Jenni; Kilgore, Brian; Goldsby, David

2014-12-01

In this study, rock friction "stick-slip" experiments are used to develop constraints on models of earthquake recurrence. Constant rate loading of bare rock surfaces in high-quality experiments produces stick-slip recurrence that is periodic at least to second order. When the loading rate is varied, recurrence is approximately inversely proportional to loading rate. These laboratory events initiate due to a slip-rate-dependent process that also determines the size of the stress drop and, as a consequence, stress drop varies weakly but systematically with loading rate. This is especially evident in experiments where the loading rate is changed by orders of magnitude, as is thought to be the loading condition of naturally occurring, small repeating earthquakes driven by afterslip, or low-frequency earthquakes loaded by episodic slip. The experimentally observed stress drops are well described by a logarithmic dependence on recurrence interval that can be cast as a nonlinear slip predictable model. The fault's rate dependence of strength is the key physical parameter. Additionally, even at constant loading rate the most reproducible laboratory recurrence is not exactly periodic, unlike existing friction recurrence models. We present example laboratory catalogs that document the variance and show that in large catalogs, even at constant loading rate, stress drop and recurrence covary systematically. The origin of this covariance is largely consistent with variability of the dependence of fault strength on slip rate. Laboratory catalogs show aspects of both slip and time predictability, and successive stress drops are strongly correlated indicating a "memory" of prior slip history that extends over at least one recurrence cycle.

Estimate variable importance for recurrent event outcomes with an application to identify hypoglycemia risk factors.

PubMed

Duan, Ran; Fu, Haoda

2015-08-30

Recurrent event data are an important data type for medical research. In particular, many safety endpoints are recurrent outcomes, such as hypoglycemic events. For such a situation, it is important to identify the factors causing these events and rank these factors by their importance. Traditional model selection methods are not able to provide variable importance in this context. Methods that are able to evaluate the variable importance, such as gradient boosting and random forest algorithms, cannot directly be applied to recurrent events data. In this paper, we propose a two-step method that enables us to evaluate the variable importance for recurrent events data. We evaluated the performance of our proposed method by simulations and applied it to a data set from a diabetes study. Copyright © 2015 John Wiley & Sons, Ltd.

Solving differential equations with unknown constitutive relations as recurrent neural networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hagge, Tobias J.; Stinis, Panagiotis; Yeung, Enoch H.

We solve a system of ordinary differential equations with an unknown functional form of a sink (reaction rate) term. We assume that the measurements (time series) of state variables are partially available, and use a recurrent neural network to “learn” the reaction rate from this data. This is achieved by including discretized ordinary differential equations as part of a recurrent neural network training problem. We extend TensorFlow’s recurrent neural network architecture to create a simple but scalable and effective solver for the unknown functions, and apply it to a fedbatch bioreactor simulation problem. Use of techniques from recent deep learningmore » literature enables training of functions with behavior manifesting over thousands of time steps. Our networks are structurally similar to recurrent neural networks, but differ in purpose, and require modified training strategies.« less

Altered intraoperative cerebrovascular reactivity in brain areas of high-grade glioma recurrence.

PubMed

Fierstra, Jorn; van Niftrik, Bas; Piccirelli, Marco; Burkhardt, Jan Karl; Pangalu, Athina; Kocian, Roman; Valavanis, Antonios; Weller, Michael; Regli, Luca; Bozinov, Oliver

2016-07-01

Current MRI sequences are limited in identifying brain areas at risk for high grade glioma recurrence. We employed intraoperative 3-Tesla functional MRI to assess cerebrovascular reactivity (CVR) after high-grade glioma resection and analyzed regional CVR responses in areas of tumor recurrence on clinical follow-up imaging. Five subjects with high-grade glioma that underwent an intraoperative Blood Oxygen-Level Dependent (BOLD) MRI CVR examination and had a clinical follow-up of at least 18months were selected from a prospective database. For this study, location of tumor recurrence was spatially matched to the intraoperative imaging to assess CVR response in that particular area. CVR is defined as the percent BOLD signal change during repeated cycles of apnea. Of the 5 subjects (mean age 44, 2 females), 4 were diagnosed with a WHO grade III and 1 subject with a WHO grade IV glioma. Three subjects exhibited a tumor recurrence on clinical follow-up MRI (mean: 15months). BOLD CVR measured in the spatially matched area of tumor recurrence was on average 94% increased (range-32% to 183%) as compared to contralateral hemisphere CVR response, 1.50±0.81 versus 1.03±0.46 respectively (p=0.31). For this first analysis in a small cohort, we found altered intraoperative CVR in brain areas exhibiting high grade glioma recurrence on clinical follow-up imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

Simulator platform motion -- the need revisited

DOT National Transportation Integrated Search

1997-05-13

The need to provide increased access to flight simulator training for U.S. regional airlines, which historically have been limited by cost considerations in the use of such equipment for pilot recurrent training, is discussed. In light of that need, ...

VERA Core Simulator Methodology for PWR Cycle Depletion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kochunas, Brendan; Collins, Benjamin S; Jabaay, Daniel

2015-01-01

This paper describes the methodology developed and implemented in MPACT for performing high-fidelity pressurized water reactor (PWR) multi-cycle core physics calculations. MPACT is being developed primarily for application within the Consortium for the Advanced Simulation of Light Water Reactors (CASL) as one of the main components of the VERA Core Simulator, the others being COBRA-TF and ORIGEN. The methods summarized in this paper include a methodology for performing resonance self-shielding and computing macroscopic cross sections, 2-D/1-D transport, nuclide depletion, thermal-hydraulic feedback, and other supporting methods. These methods represent a minimal set needed to simulate high-fidelity models of a realistic nuclearmore » reactor. Results demonstrating this are presented from the simulation of a realistic model of the first cycle of Watts Bar Unit 1. The simulation, which approximates the cycle operation, is observed to be within 50 ppm boron (ppmB) reactivity for all simulated points in the cycle and approximately 15 ppmB for a consistent statepoint. The verification and validation of the PWR cycle depletion capability in MPACT is the focus of two companion papers.« less

Vocal cord dysfunction in a child.

PubMed

Juliá, J C; Martorell, A; Armengot, M A; Lluch, R; Boluda, C F; Cerdá, J C; Alvarez, V

1999-07-01

Vocal cord dysfunction (VCD) involves paradoxical adduction of the vocal cord during the respiratory cycle. This usually occurs during inspiration, but can also be seen in expiration. Vocal cord appositioning produces airflow obstruction sufficient to cause wheezing, shortness of breath, chest tightness, and coughing. These symptoms often imitate the respiratory alterations of asthma, thus leading to inappropriate treatment; intubation or tracheotomy may prove necessary. An 11-year-old girl was admitted with intractable dyspnea. She had been diagnosed with atopic asthma, although she failed to respond to an increase in antiasthma medication, including high-dose oral steroids. Flow-volume loops were abnormal, with evidence of variable extrathoracic airway obstruction, manifested as a flat inspiratory loop. No structural abnormalities were seen with either computed tomography (CT) or magnetic resonance imaging (MRI). Fibroscopy revealed paradoxical adduction of the vocal cords during the respiratory cycle, no obstructive disorder being observed. After the diagnosis of VCD, the clinical manifestations resolved with psychiatric treatment. Adduction was not demonstrable at repeat fibroscopy after treatment. VCD may simulate bronchial asthma; it may also be associated with that disorder, thus masking the diagnosis. It should be suspected in patients with recurrent wheezing who fail to respond to usual asthma treatment. An early diagnosis avoids unnecessary aggressive management. Treatment should consist of respiratory and phonatory exercises; psychotherapy may be useful.

A clinical data validated mathematical model of prostate cancer growth under intermittent androgen suppression therapy

NASA Astrophysics Data System (ADS)

Portz, Travis; Kuang, Yang; Nagy, John D.

2012-03-01

Prostate cancer is commonly treated by a form of hormone therapy called androgen suppression. This form of treatment, while successful at reducing the cancer cell population, adversely affects quality of life and typically leads to a recurrence of the cancer in an androgen-independent form. Intermittent androgen suppression aims to alleviate some of these adverse affects by cycling the patient on and off treatment. Clinical studies have suggested that intermittent therapy is capable of maintaining androgen dependence over multiple treatment cycles while increasing quality of life during off-treatment periods. This paper presents a mathematical model of prostate cancer to study the dynamics of androgen suppression therapy and the production of prostate-specific antigen (PSA), a clinical marker for prostate cancer. Preliminary models were based on the assumption of an androgen-independent (AI) cell population with constant net growth rate. These models gave poor accuracy when fitting clinical data during simulation. The final model presented hypothesizes an AI population with increased sensitivity to low levels of androgen. It also hypothesizes that PSA production is heavily dependent on androgen. The high level of accuracy in fitting clinical data with this model appears to confirm these hypotheses, which are also consistent with biological evidence.

Intermediate Fidelity Closed Brayton Cycle Power Conversion Model

NASA Technical Reports Server (NTRS)

Lavelle, Thomas M.; Khandelwal, Suresh; Owen, Albert K.

2006-01-01

This paper describes the implementation of an intermediate fidelity model of a closed Brayton Cycle power conversion system (Closed Cycle System Simulation). The simulation is developed within the Numerical Propulsion Simulation System architecture using component elements from earlier models. Of particular interest, and power, is the ability of this new simulation system to initiate a more detailed analysis of compressor and turbine components automatically and to incorporate the overall results into the general system simulation.

Computer Simulation Of Cyclic Oxidation

NASA Technical Reports Server (NTRS)

Probst, H. B.; Lowell, C. E.

1990-01-01

Computer model developed to simulate cyclic oxidation of metals. With relatively few input parameters, kinetics of cyclic oxidation simulated for wide variety of temperatures, durations of cycles, and total numbers of cycles. Program written in BASICA and run on any IBM-compatible microcomputer. Used in variety of ways to aid experimental research. In minutes, effects of duration of cycle and/or number of cycles on oxidation kinetics of material surveyed.

Recurrence quantification analysis applied to spatiotemporal pattern analysis in high-density mapping of human atrial fibrillation.

PubMed

Zeemering, Stef; Bonizzi, Pietro; Maesen, Bart; Peeters, Ralf; Schotten, Ulrich

2015-01-01

Spatiotemporal complexity of atrial fibrillation (AF) patterns is often quantified by annotated intracardiac contact mapping. We introduce a new approach that applies recurrence plot (RP) construction followed by recurrence quantification analysis (RQA) to epicardial atrial electrograms, recorded with a high-density grid of electrodes. In 32 patients with no history of AF (aAF, n=11), paroxysmal AF (PAF, n=12) and persistent AF (persAF, n=9), RPs were constructed using a phase space electrogram embedding dimension equal to the estimated AF cycle length. Spatial information was incorporated by 1) averaging the recurrence over all electrodes, and 2) by applying principal component analysis (PCA) to the matrix of embedded electrograms and selecting the first principal component as a representation of spatial diversity. Standard RQA parameters were computed on the constructed RPs and correlated to the number of fibrillation waves per AF cycle (NW). Averaged RP RQA parameters showed no correlation with NW. Correlations improved when applying PCA, with maximum correlation achieved between RP threshold and NW (RR1%, r=0.68, p <; 0.001) and RP determinism (DET, r=-0.64, p <; 0.001). All studied RQA parameters based on the PCA RP were able to discriminate between persAF and aAF/PAF (DET persAF 0.40 ± 0.11 vs. 0.59 ± 0.14/0.62 ± 0.16, p <; 0.01). RP construction and RQA combined with PCA provide a quick and reliable tool to visualize dynamical behaviour and to assess the complexity of contact mapping patterns in AF.

Pathological complete response following neoadjuvant radiotherapy and intraperitoneal perfusion chemotherapy for recurrent colon carcinoma: A case report and literature review

PubMed Central

BIAN, XINYU; LIU, BAORUI; YANG, YANG

2016-01-01

The present study reports the case of a 28-year-old male who was diagnosed with sigmoid colon carcinoma and exhibited local recurrence following radical surgery and 6 cycles of adjuvant chemotherapy. The primary surgery consisted of a partial sigmoidectomy and bladder repair. At 8 months post-chemotherapy, the patient was referred to Nanjing Drum Tower Hospital (Nanjing, China) due to local recurrence at the anastomotic site, which was confirmed by colonoscopy and total abdominal computed tomography. Synchronous intensity modulation radiation therapy and intraperitoneal (IP) perfusion chemotherapy with irinotecan (100 mg/m2) was administered. Following treatment, the object efficacy evaluation revealed a complete response and a second resection of the remaining sigmoid colon was performed. The post-operative results showed a pathological complete response. This case indicated that a combination of therapies, including radiotherapy, IP perfusion chemotherapy and surgery, may be beneficial and effective in patients with recurrent colon cancer. PMID:27073546

A rare case of recurrent ovarian cancer presenting as a round ligament metastasis.

PubMed

Togami, Shinichi; Kato, Tomoyasu; Oi, Takateru; Ishikawa, Mitsuya; Onda, Takashi; Ikeda, Shun-ichi; Kasamatsu, Takahiro

2011-11-07

We report a rare case of recurrent ovarian cancer presenting as a round ligament metastasis. A 44-year-old woman presented with a lower abdominal mass. Computed tomography showed a pelvic mass. Primary surgery was performed. A histopathological examination showed an ovarian serous adenocarcinoma of Stage IIIb. The patient received 6 cycles of paclitaxel and carboplatin. Almost 2 years after the initial operation, the patient noticed a left inguinal mass. Computed tomography showed a left inguinal mass, 18 mm in size. An excisional biopsy was performed and the tumor was found to originate in the left round ligament. A histopathological examination showed serous adenocarcinoma and there was no evidence of lymph node tissue. Recurrence of ovarian cancer in the round ligament is extremely rare. This unique case suggests, however, that the round ligament in rare cases may be a recurrence site for ovarian cancer, and that accurate differentiation including confirmation by diagnostic imaging and excisional biopsy, is necessary for a definitive pathological diagnosis.

The effect of simulator motion on pilot training and evaluation

DOT National Transportation Integrated Search

2000-08-14

This study empirically examined the effect of simulator platform motion on airline pilot recurrent training and evaluation. It is driven by the need for sound scientific data on the relationship between certain key modern device features and their ef...

RUBIC identifies driver genes by detecting recurrent DNA copy number breaks

PubMed Central

van Dyk, Ewald; Hoogstraat, Marlous; ten Hoeve, Jelle; Reinders, Marcel J. T.; Wessels, Lodewyk F. A.

2016-01-01

The frequent recurrence of copy number aberrations across tumour samples is a reliable hallmark of certain cancer driver genes. However, state-of-the-art algorithms for detecting recurrent aberrations fail to detect several known drivers. In this study, we propose RUBIC, an approach that detects recurrent copy number breaks, rather than recurrently amplified or deleted regions. This change of perspective allows for a simplified approach as recursive peak splitting procedures and repeated re-estimation of the background model are avoided. Furthermore, we control the false discovery rate on the level of called regions, rather than at the probe level, as in competing algorithms. We benchmark RUBIC against GISTIC2 (a state-of-the-art approach) and RAIG (a recently proposed approach) on simulated copy number data and on three SNP6 and NGS copy number data sets from TCGA. We show that RUBIC calls more focal recurrent regions and identifies a much larger fraction of known cancer genes. PMID:27396759

Nonlinear recurrent neural networks for finite-time solution of general time-varying linear matrix equations.

PubMed

Xiao, Lin; Liao, Bolin; Li, Shuai; Chen, Ke

2018-02-01

In order to solve general time-varying linear matrix equations (LMEs) more efficiently, this paper proposes two nonlinear recurrent neural networks based on two nonlinear activation functions. According to Lyapunov theory, such two nonlinear recurrent neural networks are proved to be convergent within finite-time. Besides, by solving differential equation, the upper bounds of the finite convergence time are determined analytically. Compared with existing recurrent neural networks, the proposed two nonlinear recurrent neural networks have a better convergence property (i.e., the upper bound is lower), and thus the accurate solutions of general time-varying LMEs can be obtained with less time. At last, various different situations have been considered by setting different coefficient matrices of general time-varying LMEs and a great variety of computer simulations (including the application to robot manipulators) have been conducted to validate the better finite-time convergence of the proposed two nonlinear recurrent neural networks. Copyright © 2017 Elsevier Ltd. All rights reserved.

Geometry and Pore Pressure Shape the Pattern of the Tectonic Tremors Activity on the Deep San Andreas Fault with Periodic, Period-Multiplying Recurrence Intervals

NASA Astrophysics Data System (ADS)

Mele Veedu, D.; Barbot, S.

2014-12-01

A never before recorded pattern of periodic, chaotic, and doubled, earthquake recurrence intervals was detected in the sequence of deep tectonic tremors of the Parkfield segment of the San Andreas Fault (Shelly, 2010). These observations may be the most puzzling seismological observations of the last decade: The pattern was regularly oscillating with a period doubling of 3 and 6 days from mid-2003 until it was disrupted by the 2004 Mw 6.0 Parkfield earthquake. But by the end of 2007, the previous pattern resumed. Here, we assume that the complex dynamics of the tremors is caused by slip on a single asperity on the San Andreas Fault with homogeneous friction properties. We developed a three-dimensional model based on the rate-and-state friction law with a single patch and simulated fault slip during all stages of the earthquake cycle using the boundary integral method of Lapusta & Liu (2009). We find that homogeneous penny-shaped asperities cannot induce the observed period doubling, and that the geometry itself of the velocity-weakening asperity is critical in enabling the characteristic behavior of the Parkfield tremors. We also find that the system is sensitive to perturbations in pore pressure, such that the ones induced by the 2004 Parkfield earthquake are sufficient to dramatically alter the dynamics of the tremors for two years, as observed by Shelly (2010). An important finding is that tremor magnitude is amplified more by macroscopic slip duration on the source asperity than by slip amplitude, indicative of a time-dependent process for the breakage of micro-asperities that leads to seismic emissions. Our simulated event duration is in the range of 25 to 150 seconds, closely comparable to the event duration of a typical Parkfield tectonic tremor. Our simulations reproduce the unique observations of the Parkfield tremor activity. This study vividly illustrates the critical role of geometry in shaping the dynamics of fault slip evolution on a seismogenic fault.

Controls on the long term earthquake behavior of an intraplate fault revealed by U-Th and stable isotope analyses of syntectonic calcite veins

NASA Astrophysics Data System (ADS)

Williams, Randolph; Goodwin, Laurel; Sharp, Warren; Mozley, Peter

2017-04-01

U-Th dates on calcite precipitated in coseismic extension fractures in the Loma Blanca normal fault zone, Rio Grande rift, NM, USA, constrain earthquake recurrence intervals from 150-565 ka. This is the longest direct record of seismicity documented for a fault in any tectonic environment. Combined U-Th and stable isotope analyses of these calcite veins define 13 distinct earthquake events. These data show that for more than 400 ka the Loma Blanca fault produced earthquakes with a mean recurrence interval of 40 ± 7 ka. The coefficient of variation for these events is 0.40, indicating strongly periodic seismicity consistent with a time-dependent model of earthquake recurrence. Stochastic statistical analyses further validate the inference that earthquake behavior on the Loma Blanca was time-dependent. The time-dependent nature of these earthquakes suggests that the seismic cycle was fundamentally controlled by a stress renewal process. However, this periodic cycle was punctuated by an episode of clustered seismicity at 430 ka. Recurrence intervals within the earthquake cluster were as low as 5-11 ka. Breccia veins formed during this episode exhibit carbon isotope signatures consistent with having formed through pronounced degassing of a CO2 charged brine during post-failure, fault-localized fluid migration. The 40 ka periodicity of the long-term earthquake record of the Loma Blanca fault is similar in magnitude to recurrence intervals documented through paleoseismic studies of other normal faults in the Rio Grande rift and Basin and Range Province. We propose that it represents a background rate of failure in intraplate extension. The short-term, clustered seismicity that occurred on the fault records an interruption of the stress renewal process, likely by elevated fluid pressure in deeper structural levels of the fault, consistent with fault-valve behavior. The relationship between recurrence interval and inferred fluid degassing suggests that pore fluid pressure along the fault may have been driven by variations in CO2 content, thereby fundamentally affecting earthquake frequency. Thus, the Loma Blanca fault provides a record of "naturally induced" seismicity, with lessons for better understanding anthropogenic induced seismicity.

Recurrence plots of discrete-time Gaussian stochastic processes

NASA Astrophysics Data System (ADS)

Ramdani, Sofiane; Bouchara, Frédéric; Lagarde, Julien; Lesne, Annick

2016-09-01

We investigate the statistical properties of recurrence plots (RPs) of data generated by discrete-time stationary Gaussian random processes. We analytically derive the theoretical values of the probabilities of occurrence of recurrence points and consecutive recurrence points forming diagonals in the RP, with an embedding dimension equal to 1. These results allow us to obtain theoretical values of three measures: (i) the recurrence rate (REC) (ii) the percent determinism (DET) and (iii) RP-based estimation of the ε-entropy κ(ε) in the sense of correlation entropy. We apply these results to two Gaussian processes, namely first order autoregressive processes and fractional Gaussian noise. For these processes, we simulate a number of realizations and compare the RP-based estimations of the three selected measures to their theoretical values. These comparisons provide useful information on the quality of the estimations, such as the minimum required data length and threshold radius used to construct the RP.

A proteome analysis of freezing tolerance in red clover (Trifolium pratense L.).

PubMed

Bertrand, Annick; Bipfubusa, Marie; Castonguay, Yves; Rocher, Solen; Szopinska-Morawska, Aleksandra; Papadopoulos, Yousef; Renaut, Jenny

2016-03-10

Improvement of freezing tolerance of red clover (Trifolium pratense L.) would increase its persistence under cold climate. In this study, we assessed the freezing tolerance and compared the proteome composition of non-acclimated and cold-acclimated plants of two initial cultivars of red clover: Endure (E-TF0) and Christie (C-TF0) and of populations issued from these cultivars after three (TF3) and four (TF4) cycles of phenotypic recurrent selection for superior freezing tolerance. Through this approach, we wanted to identify proteins that are associated with the improvement of freezing tolerance in red clover. Freezing tolerance expressed as the lethal temperature for 50 % of the plants (LT50) increased markedly from approximately -2 to -16 °C following cold acclimation. Recurrent selection allowed a significant 2 to 3 °C increase of the LT50 after four cycles of recurrent selection. Two-dimensional difference gel electrophoresis (2D-DIGE) was used to study variations in protein abundance. Principal component analysis based on 2D-DIGE revealed that the largest variability in the protein data set was attributable to the cold acclimation treatment and that the two genetic backgrounds had differential protein composition in the acclimated state only. Vegetative storage proteins (VSP), which are essential nitrogen reserves for plant regrowth, and dehydrins were among the most striking changes in proteome composition of cold acclimated crowns of red clovers. A subset of proteins varied in abundance in response to selection including a dehydrin that increased in abundance in TF3 and TF4 populations as compared to TF0 in the Endure background. Recurrent selection performed indoor is an effective approach to improve the freezing tolerance of red clover. Significant improvement of freezing tolerance by recurrent selection was associated with differential accumulation of a small number of cold-regulated proteins that may play an important role in the determination of the level of freezing tolerance.

Phase II Evaluation of Pemetrexed in the Treatment of Recurrent or Persistent Platinum-Resistant Ovarian or Primary Peritoneal Carcinoma: A Study of the Gynecologic Oncology Group

PubMed Central

Miller, David S.; Blessing, John A.; Krasner, Carolyn N.; Mannel, Robert S.; Hanjani, Parviz; Pearl, Michael L.; Waggoner, Steven E.; Boardman, Cecelia H.

2009-01-01

Purpose To estimate the antitumor activity of pemetrexed in patients with persistent or recurrent platinum-resistant epithelial ovarian or primary peritoneal cancer and to determine the nature and degree of toxicities. Patients and Methods A phase II trial was conducted by the Gynecologic Oncology Group. Patients must have had cancer that had progressed on platinum-based primary chemotherapy or recurred within 6 months. Pemetrexed at a dose of 900 mg/m2 was to be administered as an intravenous infusion over 10 minutes every 21 days. Dose delay and adjustment was permitted for toxicity. Treatment was continued until disease progression or unacceptable adverse effects. Results From July 6, 2004, to August 23, 2006, 51 patients were entered. A total of 259 cycles (median, four; range one to 19 cycles) of pemetrexed were administered, with 40% of patients receiving six or more cycles. Overall, the treatment was well tolerated. More serious toxicities (grade 3 and 4) included neutropenia in 42%, leukopenia in 25%, anemia in 15%, and constitutional in 15% of patients. No treatment-related deaths were reported. One patient (2%) had a complete and nine patients (19%) had partial responses, with a median duration response of 8.4 months. Seventeen patients (35%) had stable disease for a median of 4.1 months. Eighteen patients (38%) had increasing disease. Three patients (6%) were not assessable. Median progression-free survival was 2.9 months, and overall survival was 11.4 months. Conclusion Pemetrexed has sufficient activity in the treatment of recurrent platinum-resistant ovarian cancer at the dose and schedule tested to warrant further investigation. PMID:19332726

Case reports to suggest an algorithm for management of total fertilisation failure prior to use of donor gametes.

PubMed

Nicopoullos, James D M; Whitney, E; Wells, V; Batha, S; Faris, R; Abdalla, H

2015-11-01

Total fertilisation failure (TFF), even with intracytoplasmic sperm injection (ICSI), occurs in approximately 3 % of cycles, can be recurrent and the exact cause is difficult to elucidate. Differentiation between oocyte and sperm-related cause of TFF is possible using mouse oocyte-activation techniques, but is not an option within most clinical settings. Therefore, the management of these couples is clinically driven, and the endpoint, if recurrent, is often the use of donor gametes. However, with the invariable lack of a definitive cause of TFF, any decision between the use of donor sperm or oocytes remains an emotive one. We present two case reports demonstrating the importance of appropriate investigation, activation techniques (mechanical and chemical) and clinical management options to develop a clinical algorithm prior to the use of donor gametes. This study is composed of two case reports of assisted reproduction investigation and treatment within an assisted conception unit for couples with recurrent total fertilisation failure. Using appropriate investigation (endocrine, urological and embryological) and treatments (ICSI, IMSI, oocyte-activation techniques), a fertilisation rate of 48 % was achieved in two cycles in couples following a total of nine previous cycles (and 200 previously collected eggs) with TFF. Oocyte activation requires the triggering of intracellular calcium oscillations by the release of a sperm-specific factor (phospholipase C zeta (PLCζ)) into the oocyte cytoplasm. Although, PLCζ deficiencies have been demonstrated as putative causes of failed activation, impaired oocyte responsiveness may also be a factor. The use of donor gametes is often recommended and is often the required endpoint of treatment. However, these reports outline a clinical algorithm that potentially offers success without donation, and also offers a systematic approach to help decide whether donor oocytes or sperm should be recommended.

The role of G-CSF in recurrent implantation failure: A randomized double blind placebo control trial.

PubMed

Davari-Tanha, Fatemeh; Shahrokh Tehraninejad, Ensieh; Ghazi, Mohadese; Shahraki, Zahra

2016-12-01

Recurrent implantation failure (RIF) is the absence of implantation after three consecutive In Vitro Fertilization (IVF) cycles with transferring at least four good quality embryos in a minimum of three fresh or frozen cycles in a woman under 40 years. The definition and management of RIF is under constant scrutiny. To investigate the effects of Granulocyte colony stimulating factor (G-CSF) on RIF, pregnancy rate, abortion rate and implantation rates. A double blind placebo controlled randomized trial was conducted at two tertiary university based hospitals. One hundred patients with the history of RIF from December 2011 until January 2014 were recruited in the study. G-CSF 300µg/1ml was administered at the day of oocyte puncture or day of progesterone administration of FET cycle. Forty patients were recruited at G-CSF group, 40 in saline and 20 in placebo group. The mean age for whole study group was 35.3±4.2 yrs (G-CSF 35.5±4.32, saline 35.3±3.98, placebo 35.4±4.01, respectively). Seventeen patients had a positive pregnancy test after embryo transfer [10 (25%) in G-CSF; 5 (12.5%) in saline; and 2 (10%) in placebo group]. The mean of abortion rates was 17.6% (3), two of them in G-CSF, one in saline group. The implantation rate was 12.3% in G-CSF, 6.1% in saline and 4.7% in placebo group. G-CSF may increase chemical pregnancy and implantation rate in patients with recurrent implantation failure but clinical pregnancy rate and abortion rate was unaffected.

Estimate of genetic gain in popcorn after cycles of phenotypic recurrent selection.

PubMed

Ematné, H J; Nunes, J A R; Dias, K O G; Prado, P E R; Souza, J C

2016-05-20

Popcorn is widely consumed in Brazil, yet there are few breeding programs for this crop. Recurrent selection (RS) is a viable breeding alternative for popcorn; however, the gains achieved must be frequently checked. The aim of this study was to assess the effect of selection for grain type (round and pointed) after four cycles of phenotypic RS on the main agronomic traits of popcorn, to estimate the genetic gain achieved for the trait of expansion volume (EV), and to obtain estimates of phenotypic correlations for the main traits of the crop in the UFLA E and UFLA R populations. The zero, one, two, and three cycles of the UFLA E and UFLA R populations, the fourth cycle, and the controls IAC-112 and IAC-125 were used. The experiments were conducted at the experimental farm of Universidade Federal de Lavras (UFLA; Environment 1) and at the experimental area of the Genetics and Plant Breeding Sector of the Department of Biology at UFLA (Environment 2) in the 2010/11 crop season. Nine agronomic traits were evaluated, including EV and grain yield (GY). The UFLA R and UFLA E populations showed similar behavior for all evaluated traits. The type of grain did not affect the genetic gain for EV, which was 5 and 3.7% in each cycle carried out in the UFLA E and UFLA R population, respectively. Phenotypic selection carried out during recombination for EV is an effective method for increasing expression of the trait. EV and GY did not show a linear association.

Genetic progress estimation strategy for upright common bean plants using recurrent selection.

PubMed

Pereira, L A; Abreu, A F B; Júnior, I C Vieira; Pires, L P M; Ramalho, M A P

2017-03-22

Common bean producers in Brazil tend to grow plants as upright as possible. Because the control of this trait involves a large number of genes, recurrent selection (RS) is the best approach for successful plant improvement. Because plant architecture (PA) is evaluated using scores and usually has high heritability, RS for PA is performed through visual selection in generation S 0 . The aim of the present study was to evaluate selection progress and investigate whether this progress varies with the number of selected progenies or the generation evaluated. In addition, the effect of RS for the upright (PA) trait on progeny grain yield (GY) was investigated. Data of progenies S 0:3 and S 0:4 of the fifth, eighth, and twelfth cycles were used. A combined analysis of variance was performed using the adjusted means of the 47 best progenies from each generation and cycle, using two control cultivars as reference. A joint analysis of the two generations used during the evaluation of progenies for the different cycles was also performed. The genetic progress (GP) was estimated by fitting a linear regression equation to the relationship between the adjusted mean of each cycle and the number of cycles. We found that RS was efficient and the estimated GP of the evaluated progenies was 4.5%. Based on the GY heritability estimates, in more advanced generation selection for GY can be successfully performed on progenies. Thus, the selection already done for PA in F 2 could be associated to the most productive progenies.

Pilot study of vincristine, oral irinotecan, and temozolomide (VOIT regimen) combined with bevacizumab in pediatric patients with recurrent solid tumors or brain tumors.

PubMed

Wagner, Lars; Turpin, Brian; Nagarajan, Rajaram; Weiss, Brian; Cripe, Timothy; Geller, James

2013-09-01

The combination of vincristine, oral irinotecan, and temozolomide (VOIT regimen) has shown antitumor activity in a pediatric Phase I trial. To further potentiate synergy, we assessed the safety and feasibility of adding bevacizumab to VOIT for children and young adults with recurrent tumors. Patients received vincristine (1.5 mg/m(2) on day 1), oral irinotecan (90 mg/m(2) on days 1-5), temozolomide (100-150 mg/m(2) on days 1-5), and bevacizumab (15 mg/kg on day 1) in 3-week cycles, which were repeated for up to six cycles. Cefixime prophylaxis was used to reduce irinotecan-associated diarrhea. Thirteen patients received 36 total cycles. Six of the first 10 patients required dose reductions due to toxicity during the first cycle (n = 3) or subsequent cycles (n = 3), and these grade 3 side effects included prolonged nausea, dehydration, anorexia, neuropathy, diarrhea, and abdominal pain, as well as prolonged grade 4 neutropenia. After reducing daily temozolomide to 100 mg/m(2) , three additional patients tolerated therapy well without the need for dose reductions. Toxicities attributed to bevacizumab were limited to grade 1 epistaxis (1) and grade 2 proteinuria (1). Tumor responses were seen in both patients with Ewing sarcoma. Reducing temozolomide from 150 to 100 mg/m(2) /day improved tolerability, and treatment with this lower temozolomide dose was feasible and convenient as outpatient therapy. Although responses were seen in Ewing sarcoma, the benefit of adding bevacizumab remains unclear. Copyright © 2013 Wiley Periodicals, Inc.

Laboratory constraints on models of earthquake recurrence

USGS Publications Warehouse

Beeler, Nicholas M.; Tullis, Terry; Junger, Jenni; Kilgore, Brian D.; Goldsby, David L.

2014-01-01

In this study, rock friction ‘stick-slip’ experiments are used to develop constraints on models of earthquake recurrence. Constant-rate loading of bare rock surfaces in high quality experiments produces stick-slip recurrence that is periodic at least to second order. When the loading rate is varied, recurrence is approximately inversely proportional to loading rate. These laboratory events initiate due to a slip rate-dependent process that also determines the size of the stress drop [Dieterich, 1979; Ruina, 1983] and as a consequence, stress drop varies weakly but systematically with loading rate [e.g., Gu and Wong, 1991; Karner and Marone, 2000; McLaskey et al., 2012]. This is especially evident in experiments where the loading rate is changed by orders of magnitude, as is thought to be the loading condition of naturally occurring, small repeating earthquakes driven by afterslip, or low-frequency earthquakes loaded by episodic slip. As follows from the previous studies referred to above, experimentally observed stress drops are well described by a logarithmic dependence on recurrence interval that can be cast as a non-linear slip-predictable model. The fault’s rate dependence of strength is the key physical parameter. Additionally, even at constant loading rate the most reproducible laboratory recurrence is not exactly periodic, unlike existing friction recurrence models. We present example laboratory catalogs that document the variance and show that in large catalogs, even at constant loading rate, stress drop and recurrence co-vary systematically. The origin of this covariance is largely consistent with variability of the dependence of fault strength on slip rate. Laboratory catalogs show aspects of both slip and time predictability and successive stress drops are strongly correlated indicating a ‘memory’ of prior slip history that extends over at least one recurrence cycle.

Transition of chaotic motion to a limit cycle by intervention of economic policy: an empirical analysis in agriculture.

PubMed

Sakai, Kenshi; Managi, Shunsuke; Vitanov, Nikolay K; Demura, Katsuhiko

2007-04-01

This paper investigates the transition of dynamics observed in an actual real agricultural economic dataset. Lyapunov spectrum analysis is conducted on the data to distinguish deterministic chaos and the limit cycle. Chaotic and periodic oscillation were identified before and after the second oil crisis, respectively. The statitonarity of the time series is investigated using recurrence plots. This shows that government intervention might reduce market instability by removing a chaotic market's long-term unpredictability.

Time-dependent geoid anomalies at subduction zones due to the seismic cycle

NASA Astrophysics Data System (ADS)

Cambiotti, G.; Sabadini, R.; Yuen, D. A.

2018-01-01

We model the geoid anomalies excited during a megathrust earthquake cycle at subduction zones, including the interseismic phase and the contribution from the infinite series of previous earthquakes, within the frame of self-gravitating, spherically symmetric, compressible, viscoelastic Earth models. The fault cuts the whole 50 km lithosphere, dips 20°, and the slip amplitude, together with the length of the fault, are chosen in order to simulate an Mw = 9.0 earthquake, while the viscosity of the 170 km thick asthenosphere ranges from 1017 to 1020 Pa s. On the basis of a new analysis from the Correspondence Principle, we show that the geoid anomaly is characterized by a periodic anomaly due to the elastic and viscous contribution from past earthquakes and to the back-slip of the interseismic phase, and by a smaller static contribution from the steady-state response to the previous infinite earthquake cycles. For asthenospheric viscosities from 1017-1018 to 1019-1020 Pa s, the characteristic relaxation times of the Earth model change from shorter to longer timescales compared to the 400 yr earthquake recurrence time, which dampen the geoid anomaly for the higher asthenospheric viscosities, since the slower relaxation cannot contribute its whole strength within the interseismic cycle. The geoid anomaly pattern is characterized by a global, time-dependent positive upwarping of the geoid topography, involving the whole hanging wall and partially the footwall compared to the sharper elastic contribution, attaining, for a moment magnitude Mw = 9.0, amplitudes as high as 6.6 cm for the lowermost asthenospheric viscosities during the viscoelastic response compared to the elastic maximum of 3.8 cm. The geoid anomaly vanishes due to the back-slip of the interseismic phase, leading to its disappearance at the end of the cycle before the next earthquake. Our results are of importance for understanding the post-seismic and interseismic geoid patterns at subduction zones.

The cosmic baryon cycle and galaxy mass assembly in the FIRE simulations

NASA Astrophysics Data System (ADS)

Anglés-Alcázar, Daniel; Faucher-Giguère, Claude-André; Kereš, Dušan; Hopkins, Philip F.; Quataert, Eliot; Murray, Norman

2017-10-01

We use cosmological simulations from the FIRE (Feedback In Realistic Environments) project to study the baryon cycle and galaxy mass assembly for central galaxies in the halo mass range Mhalo ˜ 1010-1013 M⊙. By tracing cosmic inflows, galactic outflows, gas recycling and merger histories, we quantify the contribution of physically distinct sources of material to galaxy growth. We show that in situ star formation fuelled by fresh accretion dominates the early growth of galaxies of all masses, while the re-accretion of gas previously ejected in galactic winds often dominates the gas supply for a large portion of every galaxy's evolution. Externally processed material contributes increasingly to the growth of central galaxies at lower redshifts. This includes stars formed ex situ and gas delivered by mergers, as well as smooth intergalactic transfer of gas from other galaxies, an important but previously underappreciated growth mode. By z = 0, wind transfer, I.e. the exchange of gas between galaxies via winds, can dominate gas accretion on to ˜L* galaxies over fresh accretion and standard wind recycling. Galaxies of all masses re-accrete ≳50 per cent of the gas ejected in winds and recurrent recycling is common. The total mass deposited in the intergalactic medium per unit stellar mass formed increases in lower mass galaxies. Re-accretion of wind ejecta occurs over a broad range of time-scales, with median recycling times (˜100-350 Myr) shorter than previously found. Wind recycling typically occurs at the scale radius of the halo, independent of halo mass and redshift, suggesting a characteristic recycling zone around galaxies that scales with the size of the inner halo and the galaxy's stellar component.

Patterns of Failure After Concurrent Bevacizumab and Hypofractionated Stereotactic Radiation Therapy for Recurrent High-Grade Glioma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shapiro, Lauren Q.; Beal, Kathryn, E-mail: bealk@mskcc.org; Goenka, Anuj

2013-03-01

Purpose: Concurrent bevacizumab with hypofractionated stereotactic radiation therapy (HSRT) is safe and effective for the treatment of recurrent high-grade gliomas (HGG). The objective of this study was to characterize the patterns of failure after this treatment regimen. Methods and Materials: Twenty-four patients with recurrent enhancing HGG were previously treated on an institutional review board-approved protocol of concurrent bevacizumab and reirradiation. Patients received 30 Gy in 5 fractions to the recurrent tumor with HSRT. Brain magnetic resonance imaging (MRI) was performed every 2 cycles, and bevacizumab was continued until clinical or radiographic tumor progression according to the criteria of Macdonald etmore » al. MRI at the time of progression was fused to the HSRT treatment plan, and the location of recurrence was classified on the basis of volume within the 95% isodose line. Outcomes based on patient characteristics, tumor grade, recurrence pattern, and best response to treatment were analyzed by the Kaplan-Meier method. Results: Twenty-two patients experienced either clinical or radiographic progression. Recurrent tumor was enhancing in 15 (71.4%) and nonenhancing in 6 (28.6%) patients. Eleven patients (52.4%) had recurrence within the radiation field, 5 patients (23.8%) had marginal recurrence, and 5 patients had recurrence outside the radiation field. Pattern of enhancement and location of failure did not correlate with overall survival or progression-free survival. Radiographic response was the only variable to significantly correlate with progression-free survival. Conclusions: Despite the promising initial response seen with the addition of HSRT to bevacizumab as salvage treatment for recurrent HGG, approximately half of patients ultimately still experience failure within the radiation field. The rate of local failure with the addition of HSRT seems to be lower than that seen with bevacizumab alone in the salvage setting. Our data underscore the radioresistance of HGG and the need for better salvage treatments.« less

Wrightwood and the earthquake cycle: What a long recurrence record tells us about how faults work

USGS Publications Warehouse

Weldon, R.; Scharer, K.; Fumal, T.; Biasi, G.

2004-01-01

The concept of the earthquake cycle is so well established that one often hears statements in the popular media like, "the Big One is overdue" and "the longer it waits, the bigger it will be." Surprisingly, data to critically test the variability in recurrence intervals, rupture displacements, and relationships between the two are almost nonexistent. To generate a long series of earthquake intervals and offsets, we have conducted paleoseismic investigations across the San Andreas fault near the town of Wrightwood, California, excavating 45 trenches over 18 years, and can now provide some answers to basic questions about recurrence behavior of large earthquakes. To date, we have characterized at least 30 prehistoric earthquakes in a 6000-yr-long record, complete for the past 1500 yr and for the interval 3000-1500 B.C. For the past 1500 yr, the mean recurrence interval is 105 yr (31-165 yr for individual intervals) and the mean slip is 3.2 m (0.7-7 m per event). The series is slightly more ordered than random and has a notable cluster of events, during which strain was released at 3 times the long-term average rate. Slip associated with an earthquake is not well predicted by the interval preceding it, and only the largest two earthquakes appear to affect the time interval to the next earthquake. Generally, short intervals tend to coincide with large displacements and long intervals with small displacements. The most significant correlation we find is that earthquakes are more frequent following periods of net strain accumulation spanning multiple seismic cycles. The extent of paleoearthquake ruptures may be inferred by correlating event ages between different sites along the San Andreas fault. Wrightwood and other nearby sites experience rupture that could be attributed to overlap of relatively independent segments that each behave in a more regular manner. However, the data are equally consistent with a model in which the irregular behavior seen at Wrightwood typifies the entire southern San Andreas fault; more long event series will be required to definitively outline prehistoric rupture extents.

Optimization of automotive Rankine cycle waste heat recovery under various engine operating condition

NASA Astrophysics Data System (ADS)

Punov, Plamen; Milkov, Nikolay; Danel, Quentin; Perilhon, Christelle; Podevin, Pierre; Evtimov, Teodossi

2017-02-01

An optimization study of the Rankine cycle as a function of diesel engine operating mode is presented. The Rankine cycle here, is studied as a waste heat recovery system which uses the engine exhaust gases as heat source. The engine exhaust gases parameters (temperature, mass flow and composition) were defined by means of numerical simulation in advanced simulation software AVL Boost. Previously, the engine simulation model was validated and the Vibe function parameters were defined as a function of engine load. The Rankine cycle output power and efficiency was numerically estimated by means of a simulation code in Python(x,y). This code includes discretized heat exchanger model and simplified model of the pump and the expander based on their isentropic efficiency. The Rankine cycle simulation revealed the optimum value of working fluid mass flow and evaporation pressure according to the heat source. Thus, the optimal Rankine cycle performance was obtained over the engine operating map.

Feedforward Inhibition Allows Input Summation to Vary in Recurrent Cortical Networks

PubMed Central

2018-01-01

Abstract Brain computations depend on how neurons transform inputs to spike outputs. Here, to understand input-output transformations in cortical networks, we recorded spiking responses from visual cortex (V1) of awake mice of either sex while pairing sensory stimuli with optogenetic perturbation of excitatory and parvalbumin-positive inhibitory neurons. We found that V1 neurons’ average responses were primarily additive (linear). We used a recurrent cortical network model to determine whether these data, as well as past observations of nonlinearity, could be described by a common circuit architecture. Simulations showed that cortical input-output transformations can be changed from linear to sublinear with moderate (∼20%) strengthening of connections between inhibitory neurons, but this change away from linear scaling depends on the presence of feedforward inhibition. Simulating a variety of recurrent connection strengths showed that, compared with when input arrives only to excitatory neurons, networks produce a wider range of output spiking responses in the presence of feedforward inhibition. PMID:29682603

Expression profiling of cell cycle regulatory proteins in oropharyngeal carcinomas using tissue microarrays.

PubMed

Ribeiro, Daniel A; Nascimento, Fabio D; Fracalossi, Ana Carolina C; Gomes, Thiago S; Oshima, Celina T F; Franco, Marcello F

2010-01-01

The aim of this study was to investigate the expressions of cell cycle regulatory proteins such as p53, p16, p21, and Rb in squamous cell carcinoma of the oropharynx and their relation to histological differentiation, staging of disease, and prognosis. Paraffin blocks from 21 primary tumors were obtained from archives of the Department of Pathology, Paulista Medical School, Federal University of Sao Paulo, UNIFESP/EPM. Immunohistochemistry was used to detect the expression of p53, p16, p21, and Rb by means of tissue microarrays. Expression of p53, p21, p16 and Rb was not correlated with the stage of disease, histopathological grading or recurrence in squamous cell carcinoma of the oropharynx. Taken together, our results suggest that p53, p16, p21 and Rb are not reliable biomarkers for prognosis of the tumor severity or recurrence in squamous cell carcinoma of the oropharynx as depicted by tissue microarrays and immunohistochemistry.

A Rare Case of Intra-Endometrial Leiomyoma of Uterus Simulating Degenerated Submucosal Leiomyoma Accompanied by a Large Sertoli-Leydig Cell Tumor.

PubMed

Jeong, Kyungah; Lee, Sa Ra; Park, Sanghui

2016-03-01

A 50-year-old peri-menopausal woman presented with hard palpable mass on her lower abdomen and anemia from heavy menstrual bleeding. Ultrasonography showed a 13×12 cm sized hypoechoic solid mass in pelvis and a 2.5×2 cm hypoechoic cystic mass in uterine endometrium. Abdomino-pelvic computed tomography revealed a hypodense pelvic mass without enhancement, suggesting a leiomyoma of intraligamentary type or sex cord tumor of right ovary with submucosal myoma of uterus. Laparoscopy revealed a large Sertoli-Leydig cell tumor of right ovary with a very rare entity of intra-endometrial uterine leiomyoma accompanied by adenomyosis. The final diagnosis of ovarian sex-cord tumor (Sertoli-Leydig cell), stage Ia with intra-endometrial leiomyoma with adenomyosis, was made. Considering the large size of the tumor and poorly differentiated nature, 6 cycles of chemotherapy with Taxol and Carboplatin regimen were administered. There is neither evidence of major complications nor recurrence during 20 months' follow-up.

The schedule effect: can recurrent peak infections be reduced without vaccines, quarantines or school closings?

PubMed

Diedrichs, Danilo R; Isihara, Paul A; Buursma, Doeke D

2014-02-01

Using a basic, two transmission level seasonal SIR model, we introduce mathematical evidence for the schedule effect which asserts that major recurring peak infections can be significantly reduced by modification of the traditional school calendar. The schedule effect is observed first in simulated time histories of the infectious population. Schedules with higher average transmission rate may exhibit reduced peak infections. Splitting vacations changes the period of the oscillating transmission function and can confine limit cycles in the proportion susceptible/proportion infected phase plane. Numerical analysis of the phase plane shows the relationship between the transmission period and the maximum recurring infection peaks and period of the response. For certain transmission periods, this response may exhibit period-doubling and chaos, leading to increased peaks. Non-monotonic infectious response is also observed in conjunction with changing birth rate. We discuss how to take these effects into consideration to design an optimum school schedule with particular reference to a hypothetical developing world context. Copyright © 2013 Elsevier Inc. All rights reserved.

Magnetic Topology of a Long-Lived Coronal Condensation Site Lasting Eight Months

NASA Astrophysics Data System (ADS)

Sun, X.; Yu, S.; Liu, W.

2017-12-01

It is well known that cool material, such as prominences or coronal rain, can form in-situ by condensation of hot coronal plasma due to a runaway radiative cooling instability (a.k.a. thermal non-equilibrium). Recent observations and numerical simulations suggest that such condensations are quite common, but in quiet-Sun regions, they occur preferentially in locations where magnetic field is weak (e.g., null points) or discontinuous (e.g., current sheets). Such events usually have short lifetimes of hours to days. Surprisingly, we observed a high-latitude condensation site lasting over eight months in 2014 with recurrent and episodic condensations fueling a funnel-shaped prominence. We analyze the coronal magnetic topology to investigate the necessary condition of such a long-lived condensation site. We find that the site was directly above a poleward photospheric flux surge when the polar field polarity was close to its solar cycle reversal. The large-scale magnetic cancellation front may have sustained interchange reconnection at this location, creating suitable conditions for coronal plasma condensation.

Comparison of planktonic and biofilm-associated communities of Clostridium difficile and indigenous gut microbiota in a triple-stage chemostat gut model.

PubMed

Crowther, Grace S; Chilton, Caroline H; Todhunter, Sharie L; Nicholson, Scott; Freeman, Jane; Baines, Simon D; Wilcox, Mark H

2014-08-01

Biofilms are characteristic of some chronic or recurrent infections and this mode of growth tends to reduce treatment efficacy. Clostridium difficile infection (CDI) is associated with a high rate of recurrent symptomatic disease. The presence and behaviour of C. difficile within intestinal biofilms remains largely unexplored, but may factor in recurrent infection. A triple-stage chemostat gut model designed to facilitate the formation of intestinal biofilm was inoculated with a pooled human faecal emulsion. Bacterial populations were allowed to equilibrate before simulated CDI was induced by clindamycin (33.9 mg/L, four times daily, 7 days) and subsequently treated with vancomycin (125 mg/L, four times daily, 7 days). Indigenous gut microbiota, C. difficile total viable counts, spores, cytotoxin and antimicrobial activity in planktonic and biofilm communities were monitored during the 10 week experimental period. Vancomycin successfully treated the initial episode of simulated CDI, but ∼18 days after therapy cessation, recurrent infection occurred. Germination, proliferation and toxin production were evident within planktonic communities in both initial and recurrent CDI. In contrast, sessile C. difficile remained in dormant spore form for the duration of the experiment. The effects of and recovery from clindamycin and vancomycin exposure for sessile populations was delayed compared with responses for planktonic bacteria. Intestinal biofilms provide a potential reservoir for C. difficile spore persistence, possibly facilitating their dispersal into the gut lumen after therapeutic intervention, leading to recurrent infection. Therapeutic options for CDI could have increased efficacy if they are more effective against sessile C. difficile. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Successful treatment of simulated Clostridium difficile infection in a human gut model by fidaxomicin first line and after vancomycin or metronidazole failure.

PubMed

Chilton, C H; Crowther, G S; Freeman, J; Todhunter, S L; Nicholson, S; Longshaw, C M; Wilcox, M H

2014-02-01

Fidaxomicin reduces the risk of recurrent Clostridium difficile infection (CDI) compared with vancomycin. We investigated fidaxomicin primary or secondary treatment efficacy using a gut model. Four triple-stage chemostat gut models were inoculated with faeces. After clindamycin induction of CDI, fidaxomicin (200 mg/L twice daily), vancomycin (125 mg/L four times daily) or metronidazole (9.3 mg/L three times daily) was administered for 7 days. Following failure/CDI recurrence, fidaxomicin (200 mg/L twice daily, 7 days) was instilled. C. difficile (CD) total viable counts (TVC), spore counts (SP), toxin titres (CYT), gut bacteria counts and antimicrobial concentrations were measured throughout. Fidaxomicin instillation reduced CD TVC/SP and CYT below the limit of detection (LOD) after 2 and 4 days, respectively, with no CDI recurrence. Metronidazole instillation failed to decrease CD TVC or CYT. Vancomycin instillation reduced CD TVC and CYT to LOD by day 4, but SP persisted. Recurrence occurred 13 days after vancomycin instillation; subsequent fidaxomicin instillation reduced CD TVC/SP/CYT below the LOD from day 2. CD was isolated sporadically, with no evidence of spore recrudescence or toxin production. Fidaxomicin had a minimal effect on the microflora, except for bifidobacteria. Fidaxomicin was detected for at least 21 days post-instillation, whereas other antimicrobials were undetectable beyond ∼4 days. Fidaxomicin successfully treated simulated primary and recurrent CDI. Fidaxomicin was superior to metronidazole in reducing CD TVC and SP, and superior to vancomycin in reducing SP without recurrence of vegetative cell growth. Fidaxomicin, but not vancomycin or metronidazole, persisted in the gut model for >20 days after instillation.

Recurrence quantity analysis based on singular value decomposition

NASA Astrophysics Data System (ADS)

Bian, Songhan; Shang, Pengjian

2017-05-01

Recurrence plot (RP) has turned into a powerful tool in many different sciences in the last three decades. To quantify the complexity and structure of RP, recurrence quantification analysis (RQA) has been developed based on the measures of recurrence density, diagonal lines, vertical lines and horizontal lines. This paper will study the RP based on singular value decomposition which is a new perspective of RP study. Principal singular value proportion (PSVP) will be proposed as one new RQA measure and bigger PSVP means higher complexity for one system. In contrast, smaller PSVP reflects a regular and stable system. Considering the advantage of this method in detecting the complexity and periodicity of systems, several simulation and real data experiments are chosen to examine the performance of this new RQA.

Phase II study of Cloretazine for the treatment of adults with recurrent glioblastoma multiforme1

PubMed Central

Badruddoja, Michael A.; Penne, Kara; Desjardins, Annick; Reardon, David A.; Rich, Jeremy N.; Quinn, Jennifer A.; Sathornsumetee, Sith; Friedman, Allan H.; Bigner, Darell D.; Herndon, James E.; Cahill, Ann; Friedman, Henry S.; Vredenburgh, James J.

2007-01-01

Cloretazine (VNP40101M) is a newly synthesized alkylating agent belonging to a novel class of alkylating agents called 1,2-bis(sulfonyl)hydrazines. Agents that belong to this class do not produce vinylating and chloroethylating species, and hence this class of alkylating agents is thought to have minimal systemic toxicity. Cloretazine produces two short-lived active species: 1,2-bis(methylsulfonyl)-1-(2-chloroethyl) hydrazine (a chloroethylating species) and a thiophilic carbamoylating methylisocyanate species. The chloroethylating species preferentially produces lesions at the O6 position of guanine. The methylisocyanate species may inhibit O6-alkylguanine-DNA alkyltransferase, an important mechanism of resistance against alkylating agents. The purpose of this study was to determine the efficacy and tolerability of Cloretazine in patients with recurrent glioblastoma multiforme. The basis for the determination of efficacy was the proportion of patients alive without evidence of disease progression six months after initiation of treatment. Patients with recurrent glioblastoma multiforme received Cloretazine (300 mg/m2) intravenously every six weeks. Radiographic response, survival data, and toxicity were assessed. Thirty-two patients were enrolled. Median age was 56 years; 24 patients (75%) were men. At six months, two patients were alive and progression free, so the six-month progression-free survival (PFS) was 6%. The median PFS was 6.3 weeks. There were no objective radiographic responses. Twelve patients had stable disease for at least one cycle, but only two patients received more than three cycles. Nine patients experienced grade 4 thrombocytopenia and three patients experienced grade 4 neutropenia. Cloretazine administered every six weeks was relatively well tolerated, although this schedule has insignificant activity for patients with recurrent glioblastoma multiforme PMID:17108065

Functional molecular markers (EST-SSR) in the full-sib reciprocal recurrent selection program of maize (Zea mays L.).

PubMed

Galvão, K S C; Ramos, H C C; Santos, P H A D; Entringer, G C; Vettorazzi, J C F; Pereira, M G

2015-07-03

This study aimed to improve grain yield in the full-sib reciprocal recurrent selection program of maize from the North Fluminense State University. In the current phase of the program, the goal is to maintain, or even increase, the genetic variability within and among populations, in order to increase heterosis of the 13th cycle of reciprocal recurrent selection. Microsatellite expressed sequence tags (EST-SSRs) were used as a tool to assist the maximization step of genetic variability, targeting the functional genome. Eighty S1 progenies of the 13th recur-rent selection cycle, 40 from each population (CIMMYT and Piranão), were analyzed using 20 EST-SSR loci. Genetic diversity, observed heterozygosity, information content of polymorphism, and inbreeding co-efficient were estimated. Subsequently, analysis of genetic dissimilarity, molecular variance, and a graphical dispersion of genotypes were conducted. The number of alleles in the CIMMYT population ranged from 1 to 6, while in the Piranão population the range was from 2 to 8, with a mean of 3.65 and 4.35, respectively. As evidenced by the number of alleles, the Shannon index showed greater diversity for the Piranão population (1.04) in relation to the CIMMYT population (0.89). The genic SSR markers were effective in clustering genotypes into their respective populations before selection and an increase in the variation between populations after selection was observed. The results indicate that the study populations have expressive genetic diversity, which cor-responds to the functional genome, indicating that this strategy may contribute to genetic gain, especially in association with the grain yield of future hybrids.

BH3-mimetic small molecule inhibits the growth and recurrence of adenoid cystic carcinoma

PubMed Central

Acasigua, Gerson A.; Warner, Kristy A.; Nör, Felipe; Helman, Joseph; Pearson, Alexander T.; Fossati, Anna C.; Wang, Shaomeng; Nör, Jacques E.

2015-01-01

Objectives To evaluate the anti-tumor effect of BM-1197, a new potent and highly specific small molecule inhibitor of Bcl-2/Bcl-xL, in preclinical models of human adenoid cystic carcinoma (ACC). Methods Low passage primary human adenoid cystic carcinoma cells (UM-HACC-2A,-2B,-5,-6) and patient-derived xenograft (PDX) models (UM-PDX-HACC) were developed from surgical specimens obtained from 4 patients. The effect of BM-1197 on cell viability and cell cycle were evaluated in vitro using this panel of low passage ACC cells. The effect of BM-1197 on tumor growth, recurrence and tumor cell apoptosis in vivo was evaluated with the PDX model of ACC (UM-PDX-HACC-5). Results Exposure of low passage primary human ACC cells to BM-1197 mediated an IC50 of 0.92-2.82 μM. This correlated with an increase in the fraction of apoptotic cells (p<0.0001) and an increase in caspase-3 activity (p<0.0001), but no noticeable differences in cell cycle (p>0.05). In vivo, BM-1197 inhibited tumor growth (p=0.0256) and induced tumor cell apoptosis (p=0.0165) without causing significant systemic toxicities, as determined by mouse weight over time. Surprisingly, weekly BM-1197 decreased the incidence of tumor recurrence (p=0.0297), as determined by Kaplan-Meier analysis. Conclusion These data demonstrated that single agent BM-1197 induces apoptosis and inhibits tumor growth in preclinical models of adenoid cystic carcinoma. Notably, single agent BM-1197 inhibited tumor recurrence, which is considered a major clinical challenge in the clinical management of adenoid cystic carcinoma. Collectively, these results suggest that patients with adenoid cystic carcinoma might benefit from therapy with a BH3-mimetic small molecule. PMID:26121939

Segmentation and supercycles: A catalog of earthquake cycle complexities from the Sumatran Sunda Megathrust and other well-studied faults worldwide

NASA Astrophysics Data System (ADS)

Philibosian, B.; Meltzner, A. J.; Sieh, K.

2017-12-01

Understanding earthquake cycle processes is key to both seismic hazard and fault mechanics. A concept that has come into focus recently is that rupture segmentation and cyclicity can be complex, and that simple models of periodically repeating similar earthquakes are inadequate. The term "supercycle" has been used to describe repeating longer periods of strain accumulation that involve multiple fault ruptures. However, this term has become broadly applied, lumping together several distinct phenomena that likely have disparate underlying causes. Earthquake recurrence patterns have often been described as "clustered," but this term is also imprecise. It is necessary to develop a terminology framework that consistently and meaningfully describes all types of behavior that are observed. We divide earthquake cycle patterns into four major classes, each having different implications for seismic hazard and fault mechanics: 1) quasi-periodic similar ruptures, 2) temporally clustered similar ruptures, 3) temporally clustered complementary ruptures, also known as rupture cascades, in which neighboring fault patches fail sequentially, and 4) superimposed cycles in which neighboring fault patches have cycles with different recurrence intervals, but may occasionally rupture together. Rupture segmentation is classified as persistent, frequent, or transient depending on how reliably ruptures terminate in a given area. We discuss the paleoseismic and historical evidence currently available for each of these types of behavior on subduction zone megathrust faults worldwide. Due to the unique level of paleoseismic and paleogeodetic detail provided by the coral microatoll technique, the Sumatran Sunda megathrust provides one of the most complete records over multiple seismic cycles. Most subduction zones with sufficient data exhibit examples of persistent and frequent segmentation, with cycle patterns 1, 3, and 4 on different segments. Pattern 2 is generally confined to overlap zones between segments. This catalog of seismic cycle observations provides a basis for exploring and modeling root causes of rupture segmentation and cycle behavior. Researchers should expect to discover similar behavior styles on other megathrust faults and perhaps major crustal faults around the world.

Constraining the Long-Term Average of Earthquake Recurrence Intervals From Paleo- and Historic Earthquakes by Assimilating Information From Instrumental Seismicity

NASA Astrophysics Data System (ADS)

Zoeller, G.

2017-12-01

Paleo- and historic earthquakes are the most important source of information for the estimationof long-term recurrence intervals in fault zones, because sequences of paleoearthquakes cover more than one seismic cycle. On the other hand, these events are often rare, dating uncertainties are enormous and the problem of missing or misinterpreted events leads to additional problems. Taking these shortcomings into account, long-term recurrence intervals are usually unstable as long as no additional information are included. In the present study, we assume that the time to the next major earthquake depends on the rate of small and intermediate events between the large ones in terms of a ``clock-change'' model that leads to a Brownian Passage Time distribution for recurrence intervals. We take advantage of an earlier finding that the aperiodicity of this distribution can be related to the Gutenberg-Richter-b-value, which is usually around one and can be estimated easily from instrumental seismicity in the region under consideration. This allows to reduce the uncertainties in the estimation of the mean recurrence interval significantly, especially for short paleoearthquake sequences and high dating uncertainties. We present illustrative case studies from Southern California and compare the method with the commonly used approach of exponentially distributed recurrence times assuming a stationary Poisson process.

Global PROTOMAP profiling to search for biomarkers of early-recurrent hepatocellular carcinoma.

PubMed

Taoka, Masato; Morofuji, Noriaki; Yamauchi, Yoshio; Ojima, Hidenori; Kubota, Daisuke; Terukina, Goro; Nobe, Yuko; Nakayama, Hiroshi; Takahashi, Nobuhiro; Kosuge, Tomoo; Isobe, Toshiaki; Kondo, Tadashi

2014-11-07

This study used global protein expression profiling to search for biomarkers to predict early recurrent hepatocellular carcinoma (HCC). HCC tissues surgically resected from patients with or without recurrence within 2 years (early recurrent) after surgery were compared with adjacent nontumor tissue and with normal liver tissue. We used the PROTOMAP strategy for comparative profiling, which integrates denaturing polyacrylamide gel electrophoresis migratory rates and high-resolution, semiquantitative mass-spectrometry-based identification of in-gel-digested tryptic peptides. PROTOMAP allows examination of global changes in the size, topography, and abundance of proteins in complex tissue samples. This approach identified 8438 unique proteins from 45 708 nonredundant peptides and generated a proteome-wide map of changes in expression and proteolytic events potentially induced by intrinsic apoptotic/necrotic pathways. In the early recurrent HCC tissue, 87 proteins were differentially expressed (≥20-fold) relative to the other tissues, 46 of which were up-regulated or specifically proteolyzed and 41 of which were down-regulated. This data set consisted of proteins that fell into various functional categories, including signal transduction and cell organization and, notably, the major catalytic pathways responsible for liver function, such as the urea cycle and detoxification metabolism. We found that aberrant proteolysis appeared to occur frequently during recurrence of HCC in several key signal transducers, including STAT1 and δ-catenin. Further investigation of these proteins will facilitate the development of novel clinical applications.

Notice of release of 'Trailhead II' basin wildrye

USDA-ARS?s Scientific Manuscript database

'Trailhead II' basin wildrye [Leymus cinereus (Scribn. & Merr.) A. Love] is a tetraploid basin wildrye release for use in re-vegetation efforts on rangelands of western North America. Trailhead II is the result of two cycles of recurrent selection within the basin wildrye cultivar 'Trailhead' for r...

Chemotherapy intensity and toxicity among black and white women with advanced and recurrent endometrial cancer: a Gynecologic Oncology Group Study.

PubMed

Farley, John H; Tian, Chunqiao; Rose, G Scott; Brown, Carol L; Birrer, Michael; Risinger, John I; Thigpen, J Tate; Fleming, Gini F; Gallion, Holly H; Maxwell, G Larry

2010-01-15

The purpose of this study was to confirm whether black and white women with endometrial cancer are equally tolerant of chemotherapy and identify factors that impact survival. A retrospective review of 169 black women and 982 white women with the International Federation of Gynecologists and Obstetricians stage III, stage IV, or recurrent endometrial carcinoma was performed. All patients received doxorubicin combined with cisplatin. Chemotherapy parameters that were reviewed included relative dose, relative time, and relative dose intensity. Treatment cycles > or =7 were defined as treatment completion. Although black patients were more likely to experience grades 3-4 anemia (20% vs 14%) and genitourinary (5% vs 1%) toxicity, and less likely to experience severe gastrointestinal toxicity (10% vs 17%), the overall incidence of grades 3-4 treatment-related chemotoxicity was the same between the 2 groups (82% vs 82%). There were no differences in the number of cycles received, relative dose (0.57 vs 0.58), relative time (0.77 vs 0.78), or relative dose intensity (0.76 vs 0.76) for black and white patients. Black patients with advanced stage or recurrent endometrial cancer, treated on 4 Gynecologic Oncology Group (GOG) protocols, had similar dose intensity and severe chemotherapy-related toxicity compared with white patients, suggesting that previously described racial disparities in survival among patients in GOG trials may have an novel etiology.

CHEMOTHERAPY INTENSITY AND TOXICITY AMONG BLACK AND WHITE WOMEN WITH ADVANCED AND RECURRENT ENDOMETRIAL CANCER: A GYNECOLOGIC ONCOLOGY GROUP STUDY

PubMed Central

Farley, John H.; Tian, Chunqiao; Rose, G. Scott; Brown, Carol L.; Birrer, Michael; Risinger, John I; Thigpen, J. Tate; Fleming, Gini F.; Gallion, Holly H.; Maxwell, G. Larry

2009-01-01

OBJECTIVE: The purpose of this study was to confirm whether Black and White women with endometrial cancer are equally tolerant of chemotherapy and identify factors that impact survival. METHODS: A retrospective review of 169 Black women and 982 White women with FIGO Stage III/IV or recurrent endometrial carcinoma was performed. All patients received doxorubicin combined with cisplatin. Chemotherapy parameters that were reviewed included relative dose (RD), relative time (RT), and relative dose intensity (RDI). Treatment cycles ≥ 7 were defined as treatment completion. RESULTS: Although Black patients were more likely to experience grade 3-4 anemia (20% vs. 14%) and genitourinary (5% vs. 1%) toxicity, and less likely to experience severe GI toxicity (10% vs. 17%), the overall incidence of grade 3-4 treatment-related chemotoxicity was the same between the two groups (82% vs. 82%). There were no differences in the number of cycles received, RD (0.57 vs. 0.58), RT (0.77 vs. 0.78), or RDI (0.76 vs. 0.76) for Black and White patients. CONCLUSION: Black patients with advanced stage or recurrent endometrial cancer, treated on four GOG protocols, had similar dose intensity and severe chemotherapy-related toxicity compared to White patients, suggesting that previously described racial disparities in survival among patients in GOG trials may have an novel etiology. PMID:19924790

Recurrent slow slip event likely hastened by the 2011 Tohoku earthquake

PubMed Central

Hirose, Hitoshi; Kimura, Hisanori; Enescu, Bogdan; Aoi, Shin

2012-01-01

Slow slip events (SSEs) are another mode of fault deformation than the fast faulting of regular earthquakes. Such transient episodes have been observed at plate boundaries in a number of subduction zones around the globe. The SSEs near the Boso Peninsula, central Japan, are among the most documented SSEs, with the longest repeating history, of almost 30 y, and have a recurrence interval of 5 to 7 y. A remarkable characteristic of the slow slip episodes is the accompanying earthquake swarm activity. Our stable, long-term seismic observations enable us to detect SSEs using the recorded earthquake catalog, by considering an earthquake swarm as a proxy for a slow slip episode. Six recurrent episodes are identified in this way since 1982. The average duration of the SSE interoccurrence interval is 68 mo; however, there are significant fluctuations from this mean. While a regular cycle can be explained using a simple physical model, the mechanisms that are responsible for the observed fluctuations are poorly known. Here we show that the latest SSE in the Boso Peninsula was likely hastened by the stress transfer from the March 11, 2011 great Tohoku earthquake. Moreover, a similar mechanism accounts for the delay of an SSE in 1990 by a nearby earthquake. The low stress buildups and drops during the SSE cycle can explain the strong sensitivity of these SSEs to stress transfer from external sources. PMID:22949688

Recurrent somnolence in a 17-month-old infant: late-onset ornithine transcarbamylase (OTC) deficiency due to the novel hemizygous mutation c.535C > T (p.Leu179Phe).

PubMed

Fantur, Michaela; Karall, Daniela; Scholl-Buergi, Sabine; Häberle, Johannes; Rauchenzauner, Markus; Fruehwirth, Martin

2013-01-01

Herein, we describe a case of a now 28-month-old boy who presented at the age of 17 months with four episodes of recurrent vomiting and somnolence during a period of four months with increasing severity. A comprehensive clinical and metabolic evaluation revealed normal blood pH and blood glucose, normal cerebral computed tomography and electroencephalogram but an elevated plasma ammonia concentration, which raised the suspicion of a urea cycle disorder. The combination of elevated urinary orotic acid and plasma glutamine with normal citrulline suggested the diagnosis of ornithine transcarbamylase (OTC) deficiency, which was confirmed by molecular genetic testing revealing the novel hemizygous mutation c.535C > T (p.Leu179Phe) of the OTC gene. After restitution of anabolism by administration of parenteral glucose, substitution of citrulline and detoxification of ammonia with sodium benzoate, the patient recovered rapidly and is in a stable metabolic and neurological state since then. This case underlines that the diagnosis of a urea cycle defect should be considered in the differential diagnosis of recurrent idiopathic vomiting in combination with unexplained neurological symptoms also beyond the neonatal period due to the possibility of mild or atypical late-onset presentation (e.g. OTC deficiency in hemizygous males). Copyright © 2012 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

Quantifying Precipitation Variability on Titan Using a GCM and Implications for Observed Geomorphology

NASA Astrophysics Data System (ADS)

Faulk, Sean P.; Mitchell, Jonathan L.; Moon, Seulgi; Lora, Juan Manuel

2016-10-01

Titan's zonal-mean precipitation behavior has been widely investigated using general circulation models (GCMs), but the spatial and temporal variability of rainfall in Titan's active hydrologic cycle is less well understood. We conduct statistical analyses of rainfall, diagnosed from GCM simulations of Titan's atmosphere, to determine storm intensity and frequency. Intense storms of methane have been proposed to be critical for enabling mechanical erosion of Titan's surface, as indicated by observations of dendritic valley networks. Using precipitation outputs from the Titan Atmospheric Model (TAM), a GCM shown to realistically simulate many features of Titan's atmosphere, we quantify the precipitation variability within eight separate latitude bins for a variety of initial surface liquid distributions. We find that while the overall wettest regions are indeed the poles, the most intense rainfall generally occurs in the high mid-latitudes, between 45-67.5 degrees, consistent with recent geomorphological observations of alluvial fans concentrated at those latitudes. We also find that precipitation rates necessary for surface erosion, as estimated by Perron et al. (2006) J. Geophys. Res. 111, E11001, frequently occur at all latitudes, with recurrence intervals of less than one Titan year. Such analysis is crucial towards understanding the complex interaction between Titan's atmosphere and surface and defining the influence of precipitation on observed geomorphology.

Inhibition of Aurora-A kinase induces cell cycle arrest in epithelial ovarian cancer stem cells by affecting NFκB pathway

PubMed Central

Alvero, Ayesha B; Visintin, Irene

2011-01-01

Recurrent ovarian cancer is resistant to conventional chemotherapy. A sub-population of ovarian cancer cells, the epithelial ovarian cancer stem cells (EOC stem cells) have stemness properties, constitutive NFκB activity, and represent the chemoresistant population. Currently, there is no effective treatment that targets these cells. Aurora-A kinase (Aurora-A) is associated with tumor initiation and progression and is overexpressed in numerous malignancies. The aim of this study is to determine the effect of Aurora-A inhibition in EOC stem cells. EOC stem cells were treated with the Aurora-A inhibitor, MK-5108. Cell growth was monitored by Incucyte real-time imaging system, cell viability was measured using the Celltiter 96 assay and cytokine levels were quantified using xMAP technology. The intracellular changes associated with MK-5108 treatment are: (1) polyploidy and cell cycle arrest; (2) inhibition of NFκB activity; (3) decreased cytokine production; and (4) nuclear accumulation of IκBα. Thus, inhibition of Aurora-A decreases cell proliferation in the EOC stem cells by inducing cell cycle arrest and affecting the NFκB pathway. As EOC stem cells represent a source of recurrence and chemoresistance, these results suggest that Aurora-A inhibition may effectively target the cancer stem cell population in ovarian cancer. PMID:21623171

Unilateral Salpingectomy and Methotrexate Are Associated With a Similar Recurrence Rate of Ectopic Pregnancy in Patients Undergoing In Vitro Fertilization.

PubMed

Irani, Mohamad; Robles, Alex; Gunnala, Vinay; Spandorfer, Steven D

To determine whether different treatment approaches of ectopic pregnancy (EP), particularly unilateral salpingectomy and methotrexate, affect its recurrence rate in patients undergoing in vitro fertilization (IVF). A retrospective cohort study (Canadian Task Force classification II-2). An academic medical center. Patients with a history of a previous EP who achieved pregnancy after IVF cycles between January 2004 and August 2015 were included. The recurrence rate of EP was compared between patients who underwent different treatment approaches for a previous EP. IVF. A total of 594 patients were included. Seventeen patients had a recurrence of EP (2.9%). Patients with a history of ≥2 EPs were associated with a significantly higher recurrence rate of EP than those with 1 previous EP (8.5% vs. 1.8%; p = .01; odds ratio [OR] = 2.2; 95% confidence interval [CI], 1.2-4.4). Patients who underwent unilateral salpingectomy (n = 245) had a comparable recurrence rate of EP after IVF with those who received methotrexate (n = 283) (3.6% vs. 2.8%; p = .5; OR = 1.3; 95% CI, 0.4-3.4). This OR remained unchanged after adjusting for patient's age, number of previous EPs, number of transferred embryos, and peak estradiol level during stimulation (adjusted OR = 1.4; 95% CI, 0.5-3.8). None of the patients who underwent bilateral salpingectomy (n = 45) or salpingostomy (n = 21) had a recurrence of EP after IVF. The recurrence rate of EP significantly correlates with the number of previous EPs. Treatment of EP with methotrexate has a comparable recurrence rate of EP after IVF with unilateral salpingectomy. Therefore, the risk of recurrence should not be a reason to favor salpingectomy over methotrexate in this population. Copyright © 2017 AAGL. Published by Elsevier Inc. All rights reserved.

Eleven-Year Retrospective Report of Super-Selective Venous Sampling for the Evaluation of Recurrent or Persistent Hyperparathyroidism in 32 Patients.

PubMed

Habibollahi, Peiman; Shin, Benjamin; Shamchi, Sara P; Wachtel, Heather; Fraker, Douglas L; Trerotola, Scott O

2018-01-01

Parathyroid venous sampling (PAVS) is usually reserved for patients with persistent or recurrent hyperparathyroidism after parathyroidectomy with inconclusive noninvasive imaging studies. A retrospective study was performed to evaluate the diagnostic efficacy of super-selective PAVS (SSVS) in patients needing revision neck surgery with inconclusive imaging. Patients undergoing PAVS between 2005 and 2016 due to persistent or recurrent hyperparathyroidism following surgery were reviewed. PAVS was performed in all patients using super-selective technique. Single-value measurements within central neck veins performed as part of super-selective PAVS were used to simulate selective venous sampling (SVS) and allow for comparison to data, which might be obtained in a non-super-selective approach. 32 patients (mean age 51 ± 15 years; 8 men and 24 women) met inclusion and exclusion criteria. The sensitivity and positive predictive value (PPV) of SSVS for localizing the source of elevated PTH to a limited area in the neck or chest was 96 and 84%, respectively. Simulated SVS, on the other hand, had a sensitivity of 28% and a PPV of 89% based on the predefined gold standard. SSVS had a significantly higher sensitivity compared to simulated SVS (p < 0.001). SSVS is highly effective in localizing the source of hyperparathyroidism in patients undergoing revision surgery for hyperparathyroidism in whom noninvasive imaging studies are inconclusive. SSVS data had also markedly higher sensitivity for localizing disease in these patients compared to simulated SVS.

Different-Level Simultaneous Minimization Scheme for Fault Tolerance of Redundant Manipulator Aided with Discrete-Time Recurrent Neural Network

PubMed Central

Jin, Long; Liao, Bolin; Liu, Mei; Xiao, Lin; Guo, Dongsheng; Yan, Xiaogang

2017-01-01

By incorporating the physical constraints in joint space, a different-level simultaneous minimization scheme, which takes both the robot kinematics and robot dynamics into account, is presented and investigated for fault-tolerant motion planning of redundant manipulator in this paper. The scheme is reformulated as a quadratic program (QP) with equality and bound constraints, which is then solved by a discrete-time recurrent neural network. Simulative verifications based on a six-link planar redundant robot manipulator substantiate the efficacy and accuracy of the presented acceleration fault-tolerant scheme, the resultant QP and the corresponding discrete-time recurrent neural network. PMID:28955217

Global stabilization analysis of inertial memristive recurrent neural networks with discrete and distributed delays.

PubMed

Wang, Leimin; Zeng, Zhigang; Ge, Ming-Feng; Hu, Junhao

2018-05-02

This paper deals with the stabilization problem of memristive recurrent neural networks with inertial items, discrete delays, bounded and unbounded distributed delays. First, for inertial memristive recurrent neural networks (IMRNNs) with second-order derivatives of states, an appropriate variable substitution method is invoked to transfer IMRNNs into a first-order differential form. Then, based on nonsmooth analysis theory, several algebraic criteria are established for the global stabilizability of IMRNNs under proposed feedback control, where the cases with both bounded and unbounded distributed delays are successfully addressed. Finally, the theoretical results are illustrated via the numerical simulations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ultrasonographic Diagnosis of Cirrhosis Based on Preprocessing Using Pyramid Recurrent Neural Network

NASA Astrophysics Data System (ADS)

Lu, Jianming; Liu, Jiang; Zhao, Xueqin; Yahagi, Takashi

In this paper, a pyramid recurrent neural network is applied to characterize the hepatic parenchymal diseases in ultrasonic B-scan texture. The cirrhotic parenchymal diseases are classified into 4 types according to the size of hypoechoic nodular lesions. The B-mode patterns are wavelet transformed , and then the compressed data are feed into a pyramid neural network to diagnose the type of cirrhotic diseases. Compared with the 3-layer neural networks, the performance of the proposed pyramid recurrent neural network is improved by utilizing the lower layer effectively. The simulation result shows that the proposed system is suitable for diagnosis of cirrhosis diseases.

A recurrent neural network for solving bilevel linear programming problem.

PubMed

He, Xing; Li, Chuandong; Huang, Tingwen; Li, Chaojie; Huang, Junjian

2014-04-01

In this brief, based on the method of penalty functions, a recurrent neural network (NN) modeled by means of a differential inclusion is proposed for solving the bilevel linear programming problem (BLPP). Compared with the existing NNs for BLPP, the model has the least number of state variables and simple structure. Using nonsmooth analysis, the theory of differential inclusions, and Lyapunov-like method, the equilibrium point sequence of the proposed NNs can approximately converge to an optimal solution of BLPP under certain conditions. Finally, the numerical simulations of a supply chain distribution model have shown excellent performance of the proposed recurrent NNs.

Recurrent episcleritis in relation to menstruation: a case report.

PubMed

Rajoo, Sangeetha Govinda; Gandhewar, Jaishree

2011-09-01

To describe a case of recurrent episcleritis associated with a patient's menstrual cycle. A retrospective case review of a 39-year-old woman who presented with a 12-year history of recurrent episcleritis in relation to her menstruation. She was seen during an acute attack and started on a reducing regime of topical steroids for 5 weeks. She was then advised to use it a week before and after menstruation. Examination and investigations revealed episcleritis with a negative systems review. After starting the treatment, she was symptom free when reviewed at 4, 8, 14, and 33 weeks. Now, the patient uses topical steroids only 1 week before menstruation. Literature review revealed no recent case reports and provided insufficient evidence to understand this relationship. We recommend increased awareness and reporting because there is a need for more studies to understand this relationship and to provide evidence for management.

Effectivity of intravescical thermo-chemotherapy prophylaxis for patients with high recurrence and progression risk for non-muscle invasive bladder cancer.

PubMed

Gözen, Ali Serdar; Umari, Paolo; Scheitlin, Walter; Su, Fuat Ernis; Akin, Yigit; Rassweiler, Jens

2017-06-30

Background&Aim: High grade non-muscle invasive bladder cancer (NMIBC) is common in urological practice. Most of these cancers are or become refractory to intravesical immunotherapy and chemotherapy. Here we evaluated the efficacy of combined local bladder hyperthermia and intravesical mitomycin-C (MMC) instillation in patients with high-risk recurrent NMIBC. Between February 2014 and December 2015, 18 patients with high risk NMIBC were enrolled. Patients were treated in an outpatient basis with 6 weekly induction sessions followed by monthly maintenance sessions with intravesical MMC in local hyperthermia with bladder wall thermo-chemotherapy (BWT) system (PelvixTT system, Elmedical Ltd., Hod Hasharon, Israel). The follow-up regimen included cystoscopy after the induction cycle and thereafter with regular intervals. Time to disease recurrence was defined as time from the first intravesical treatment to endoscopic or histological documentation of a new bladder tumour. Adverse events were recorded according to CTC 4.0 (Common Toxicity Criteria) score system. Mean age was 72 (32-87) years. 10 patients had multifocal disease, 9 had CIS, 6 had recurrent disease and 2 had highly recurrent disease (> 3 recurrences in a 24 months period). 6 patients underwent previous intravesical chemotherapy with MMC. The average number of maintenance sessions per patient was 7.6. After a mean follow-up of 433 days, 15 patients (83.3%) were recurrence-free. 3 patients had tumour recurrence after a mean period of 248 days without progression. Side effects were limited to grade 1 in 2 patients and grade 2 in 1 patient. BWT seems to be feasible and safe in high grade NMIBC. More studies are needed to identify the subgroup of patients who may benefit more from this treatment.

Simulator fidelity requirements for airline pilot training and evaluation continued : an update on motion requirements research

DOT National Transportation Integrated Search

2003-04-01

Preliminary results are presented on the effect of enhanced hexapod motion on airline pilot recurrent evaluation, training, and transfer of training to the simulator with motion as a stand-in for the airplane (quasi-transfer). A first study, which te...

Analysis of the Diurnal Cycle of Precipitation and its Relation to Cloud Radiative Forcing Using TRMM Products

NASA Technical Reports Server (NTRS)

Randall, David A.; Fowler, Laura D.; Lin, Xin

1998-01-01

In order to improve our understanding of the interactions between clouds, radiation, and the hydrological cycle simulated in the Colorado State University General Circulation Model (CSU GCM), we focused our research on the analysis of the diurnal cycle of precipitation, top-of-the-atmosphere and surface radiation budgets, and cloudiness using 10-year long Atmospheric Model Intercomparison Project (AMIP) simulations. Comparisons the simulated diurnal cycle were made against the diurnal cycle of Earth Radiation Budget Experiment (ERBE) radiation budget and International Satellite Cloud Climatology Project (ISCCP) cloud products. This report summarizes our major findings over the Amazon Basin.

Multiplicity and Its Discontents: Life on the Counseling Farm

ERIC Educational Resources Information Center

Hansen, James

2010-01-01

This paper argues that a recurrent ideological theme of counseling history is the transition from viewing people as singular to conceptualizing them as multiple or diverse. Unfortunately, however, these laudable multiplicity movements regularly revert to a position of singularity. The implications of this ideological cycle for counseling practice…

Frequent fire alters nitrogen transformations in ponderosa pine stands of the inland Northwest

Treesearch

Thomas H. DeLuca; Sala Anna

2006-01-01

Recurrent, low-severity fire in ponderosa pine (Pinus ponderosa)/interior Douglas-fir (Pseudotsuga menziesii var. glauca) forests is thought to have directly influenced nitrogen (N) cycling and availability. However, no studies to date have investigated the influence of natural fire intervals on soil processes in undisturbed...

Rapid development of a castor cultivar with increased oil content

USDA-ARS?s Scientific Manuscript database

Castor seed oil contains 90% ricinoleic acid which has a wide range of industrial applications. Improvement in oil content would be of great benefit to castor growers and oil processers. Two cycles of phenotypic recurrent selection were conducted through screening for high oil content castor seeds u...

Neoadjuvant Interdigitated Chemoradiotherapy Using Mesna, Doxorubicin, and Ifosfamide for Large, High-grade, Soft Tissue Sarcomas of the Extremity: Improved Efficacy and Reduced Toxicity.

PubMed

Chowdhary, Mudit; Sen, Neilayan; Jeans, Elizabeth B; Miller, Luke; Batus, Marta; Gitelis, Steven; Wang, Dian; Abrams, Ross A

2018-05-18

Patients with large, high-grade extremity soft tissue sarcoma (STS) are at high risk for both local and distant recurrence. RTOG 95-14, using a regimen of neoadjuvant interdigitated chemoradiotherapy with mesna, doxorubicin, ifosfamide, and dacarbazine followed by surgery and 3 cycles of adjuvant mesna, doxorubicin, ifosfamide, and dacarbazine, demonstrated high rates of disease control at the cost of significant toxicity (83% grade 4, 5% grade 5). As such, this regimen has not been widely adopted. Herein, we report our institutional outcomes utilizing a modified interdigitated chemoradiotherapy regimen, without dacarbazine, and current radiotherapy planning and delivery techniques for high-risk STS. Adults with large (≥5 cm; median, 12.9 cm), grade 3 extremity STS who were prospectively treated as part of our institutional standard of care from 2008 to 2016 are included. Neoadjuvant chemoradiotherapy consisted of 3 cycles of mesna, doxorubicin, and ifosfamide (MAI) and 44 Gy (22 Gy in 11 fractions between cycles of MAI) after which patients underwent surgical resection and received 3 additional cycles of MAI. Twenty-six patients received the MAI treatment protocol. At a median follow-up of 47.3 months, 23 (88.5%) patients are still alive. Three year locoregional recurrence-free survival, disease-free survival, and overall survival are 95.0%, 64.0%, and 95.0%, respectively. There have been no therapy-related deaths or secondary malignancies. The nonhematologic grade 4 toxicity rate was 7.7%. Neoadjuvant interdigitated MAI radiotherapy followed by resection and 3 cycles of adjuvant MAI has resulted in acceptable and manageable toxicity and highly favorable survival in patients at greatest risk for treatment failure.

Improvement of resistance to rust through recurrent selection in pearl millet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tapsoba, H.; Wilson, J.P.; Hanna, W.W.

Two pearl millet [Pennisetum glaucum (L.) R.Br. = P. typhoides (Burm.) Staff & Hubb., P. americanum (L.) K. Schum.] bulk populations, Tift No. 2 and Tift No. 5, served as base populations for four cycles of recurrent selection against susceptibility to Puccinia substriata Ell. & Barth, var. indica Ramachar & Cumm. A bulk inoculum of the pathogen was used. The objectives were to evaluate the progress achieved regarding overall resistance to the pathogen in the field and resistance to different races of the pathogen, and also to evaluate changes in unselected traits. During selection, the frequency of rust resistant plantsmore » continuously increased from about 30% in each base population to more than 85% by the third cycle of selection in both populations. An average increase of about 21 and 18% per cycle was obtained in Tift No. 2 and Tift No. 5, respectively. A continuous increase of the frequency of plants resistant to some races of the pathogen was also obtained. In Tift No. 5, 80% of the plants were resistant to eight races by the third cycle of selection. The accumulation of resistance observed in the seedlings was manifested in the field, both in 1993 and 1994, by a reduction of the final rust severity from the base population to the fourth selection cycle of both populations. This improvement in resistance to the rust pathogen was accompanied by an increase in the frequency of plants resistant to Pyricularia grisea (Cooke) Sacc. only in Tift No. 2. Despite the improvement in the selected character, genetic variability for agronomic traits such as plant height, number of culms/plant, flowering date, and panicle length was successfully maintained within each population. 20 refs., 1 fig., 7 tabs.« less

Simulated space environment tests on cadmium sulfide solar cells

NASA Technical Reports Server (NTRS)

Clarke, D. R.; Oman, H.

1971-01-01

Cadmium sulfide (Cu2s - CdS) solar cells were tested under simulated space environmental conditions. Some cells were thermally cycled with illumination from a Xenon-arc solar simulator. A cycle was one hour of illumination followed immediately with one-half hour of darkness. In the light, the cells reached an equilibrium temperature of 60 C (333 K) and in the dark the cell temperature dropped to -120 C (153 K). Other cells were constantly illuminated with a Xenon-arc solar simulator. The equilibrium temperature of these cells was 55 C (328 K). The black vacuum chamber walls were cooled with liquid nitrogen to simulate a space heat sink. Chamber pressure was maintained at 0.000001 torr or less. Almost all of the solar cells tested degraded in power when exposed to a simulated space environment of either thermal cycling or constant illumination. The cells tested the longest were exposed to 10.050 thermal cycles.

Dissolution of cholesterol gall stones using methyltertbutyl ether: a safe effective treatment.

PubMed Central

McNulty, J; Chua, A; Keating, J; Ah-Kion, S; Weir, D G; Keeling, P W

1991-01-01

Methyltertbutyl ether (MTBE) administered by percutaneous transhepatic catheter rapidly dissolves radiolucent cholesterol gall bladder stones. However, complete dissolution and clearance of non-cholesterol debris is essential to prevent recurrence. In this study we analysed 25 consecutive patients with reference to efficacy and recurrence based on the presence or absence of non-cholesterol stone fragments after dissolution. Placement of the catheter was successful in 24 patients, one patient requiring cholecystectomy for bile peritonitis. MTBE was infused and aspirated continuously, four to six cycles per minute, resulting in rapid stone dissolution (median six hours; range 4-23 hours for solitary stones and median seven hours, range 4-30 hours for multiple stones). In 18 patients who had complete dissolution, four (22%) had recurrent stones within six to 18 months. Five patients had residual debris which failed to clear completely despite bile acid treatment. One patient with an incomplete rim of calcium in a large stone did not respond to MTBE treatment. A further patient required cholecystectomy for symptomatic recurrence. There were no serious side effects observed. MTBE treatment is a rapid, safe, and effective treatment for patients who refuse surgery or who for medical reasons cannot undergo cholecystectomy. The results of this study confirm that complete dissolution of all fragments is essential and may prevent recurrence. Images Figure 2 PMID:1773965

Adaptive filter design using recurrent cerebellar model articulation controller.

PubMed

Lin, Chih-Min; Chen, Li-Yang; Yeung, Daniel S

2010-07-01

A novel adaptive filter is proposed using a recurrent cerebellar-model-articulation-controller (CMAC). The proposed locally recurrent globally feedforward recurrent CMAC (RCMAC) has favorable properties of small size, good generalization, rapid learning, and dynamic response, thus it is more suitable for high-speed signal processing. To provide fast training, an efficient parameter learning algorithm based on the normalized gradient descent method is presented, in which the learning rates are on-line adapted. Then the Lyapunov function is utilized to derive the conditions of the adaptive learning rates, so the stability of the filtering error can be guaranteed. To demonstrate the performance of the proposed adaptive RCMAC filter, it is applied to a nonlinear channel equalization system and an adaptive noise cancelation system. The advantages of the proposed filter over other adaptive filters are verified through simulations.

Bevacizumab treatment of symptomatic pseudoprogression after boron neutron capture therapy for recurrent malignant gliomas. Report of 2 cases.

PubMed

Miyatake, Shin-Ichi; Furuse, Motomasa; Kawabata, Shinji; Maruyama, Takashi; Kumabe, Toshihiro; Kuroiwa, Toshihiko; Ono, Koji

2013-06-01

Bevacizumab, an anti-vascular endothelial growth factor antibody, has been used for the treatment of radiation necrosis. Thus far, however, there has been no definitive report on its use for the treatment of symptomatic pseudoprogression. Here we report 2 cases of successful treatment with bevacizumab for symptomatic pseudoprogression after boron neutron capture therapy (BNCT) was applied for recurrent malignant gliomas. Two recurrent malignant gliomas received BNCT. Both cases were treated with intravenous administration of bevacizumab at the deterioration that seemed to be symptomatic pseudoprogression. The first case was recurrent glioblastoma multiforme and the second was recurrent anaplastic oligoastrocytoma. Both cases recurred after standard chemoradiotherapy and were referred to our institute for BNCT, which is tumor-selective particle radiation. Just prior to neutron irradiation, PET with an amino acid tracer was applied in each case to confirm tumor recurrence. Both cases showed deterioration in symptoms, as well as on MRI, at intervals of 4 months and 2 months, respectively, after BNCT. For the first case, a second PET was applied in order to confirm no increase in tracer uptake. We diagnosed both cases as symptomatic pseudoprogression and started the intravenous administration of 5 mg/kg bevacizumab biweekly with 6 cycles. Both cases responded well to this, showing rapid and dramatic improvement in neuroimaging and clinical symptoms. No tumor progression was observed 8 months after BNCT. Bevacizumab showed marked effects on symptomatic pseudoprogression after BNCT. BNCT combined with bevacizumab may prolong the survival of patients with recurrent malignant gliomas.

Bevacizumab treatment of symptomatic pseudoprogression after boron neutron capture therapy for recurrent malignant gliomas. Report of 2 cases

PubMed Central

Miyatake, Shin-Ichi; Furuse, Motomasa; Kawabata, Shinji; Maruyama, Takashi; Kumabe, Toshihiro; Kuroiwa, Toshihiko; Ono, Koji

2013-01-01

Background Bevacizumab, an anti–vascular endothelial growth factor antibody, has been used for the treatment of radiation necrosis. Thus far, however, there has been no definitive report on its use for the treatment of symptomatic pseudoprogression. Here we report 2 cases of successful treatment with bevacizumab for symptomatic pseudoprogression after boron neutron capture therapy (BNCT) was applied for recurrent malignant gliomas. Methods Two recurrent malignant gliomas received BNCT. Both cases were treated with intravenous administration of bevacizumab at the deterioration that seemed to be symptomatic pseudoprogression. Results The first case was recurrent glioblastoma multiforme and the second was recurrent anaplastic oligoastrocytoma. Both cases recurred after standard chemoradiotherapy and were referred to our institute for BNCT, which is tumor-selective particle radiation. Just prior to neutron irradiation, PET with an amino acid tracer was applied in each case to confirm tumor recurrence. Both cases showed deterioration in symptoms, as well as on MRI, at intervals of 4 months and 2 months, respectively, after BNCT. For the first case, a second PET was applied in order to confirm no increase in tracer uptake. We diagnosed both cases as symptomatic pseudoprogression and started the intravenous administration of 5 mg/kg bevacizumab biweekly with 6 cycles. Both cases responded well to this, showing rapid and dramatic improvement in neuroimaging and clinical symptoms. No tumor progression was observed 8 months after BNCT. Conclusions Bevacizumab showed marked effects on symptomatic pseudoprogression after BNCT. BNCT combined with bevacizumab may prolong the survival of patients with recurrent malignant gliomas. PMID:23460324

Quality of ulcer healing in gastrointestinal tract: Its pathophysiology and clinical relevance

PubMed Central

Arakawa, Tetsuo; Watanabe, Toshio; Tanigawa, Tetsuya; Tominaga, Kazunari; Fujiwara, Yasuhiro; Morimoto, Ken’ichi

2012-01-01

In this paper, we review the concept of quality of ulcer healing (QOUH) in the gastrointestinal tract and its role in the ulcer recurrence. In the past, peptic ulcer disease (PUD) has been a chronic disease with a cycle of repeated healing/remission and recurrence. The main etiological factor of PUD is Helicobacter pylori (H. pylori), which is also the cause of ulcer recurrence. However, H. pylori-negative ulcers are present in 12%-20% of patients; they also recur and are on occasion intractable. QOUH focuses on the fact that mucosal and submucosal structures within ulcer scars are incompletely regenerated. Within the scars of healed ulcers, regenerated tissue is immature and with distorted architecture, suggesting poor QOUH. The abnormalities in mucosal regeneration can be the basis for ulcer recurrence. Our studies have shown that persistence of macrophages in the regenerated area plays a key role in ulcer recurrence. Our studies in a rat model of ulcer recurrence have indicated that proinflammatory cytokines trigger activation of macrophages, which in turn produce increased amounts of cytokines and chemokines, which attract neutrophils to the regenerated area. Neutrophils release proteolytic enzymes that destroy the tissue, resulting in ulcer recurrence. Another important factor in poor QOUH can be deficiency of endogenous prostaglandins and a deficiency and/or an imbalance of endogenous growth factors. Topically active mucosal protective and antiulcer drugs promote high QOUH and reduce inflammatory cell infiltration in the ulcer scar. In addition to PUD, the concept of QOUH is likely applicable to inflammatory bowel diseases including Crohn’s disease and ulcerative colitis. PMID:23002355

The impact of the diurnal cycle on the propagation of Madden-Julian Oscillation convection across the Maritime Continent

DOE PAGES

Hagos, Samson M.; Zhang, Chidong; Feng, Zhe; ...

2016-09-19

Influences of the diurnal cycle of convection on the propagation of the Madden-Julian Oscillation (MJO) across the Maritime Continent (MC) are examined using cloud-permitting regional model simulations and observations. A pair of ensembles of control (CONTROL) and no-diurnal cycle (NODC) simulations of the November 2011 MJO episode are performed. In the CONTROL simulations, the MJO signal is weakened as it propagates across the MC, with much of the convection stalling over the large islands of Sumatra and Borneo. In the NODC simulations, where the incoming shortwave radiation at the top of the atmosphere is maintained at its daily mean value,more » the MJO signal propagating across the MC is enhanced. Examination of the surface energy fluxes in the simulations indicates that in the presence of the diurnal cycle, surface downwelling shortwave radiation in CONTROL simulations is larger because clouds preferentially form in the afternoon. Furthermore, the diurnal co-variability of surface wind speed and skin temperature results in a larger sensible heat flux and a cooler land surface in CONTROL compared to NODC simulations. Here, an analysis of observations indicates that the modulation of the downwelling shortwave radiation at the surface by the diurnal cycle of cloudiness negatively projects on the MJO intraseasonal cycle and therefore disrupts the propagation of the MJO across the MC.« less

11- and 22-year variations of the cosmic ray density and of the solar wind speed

NASA Technical Reports Server (NTRS)

Chirkov, N. P.

1985-01-01

Cosmic ray density variations for 17-21 solar activity cycles and the solar wind speed for 20-21 events are investigated. The 22-year solar wind speed recurrence was found in even and odd cycles. The 22-year variations of cosmic ray density were found to be opposite that of solar wind speed and solar activity. The account of solar wind speed in 11-year variations significantly decreases the modulation region of cosmic rays when E = 10-20 GeV.

Protein PSMD8 may mediate microgravity-induced cell cycle arrest

NASA Astrophysics Data System (ADS)

Hang, Xiaoming; Sun, Yeqing; Xu, Dan; Wu, Di; Chen, Xiaoning

Microgravity environment of space can induce a serial of changes in cells, such as morphology alterations, cytoskeleton disorder and cell cycle disturbance. Our previous study of simulated-microgravity on zebrafish (Danio rerio) embryos demonstrated 26s proteasome non-ATPase regulatory subunit 8 (PSMD8) might be a microgravity sensitive gene. However, functional study on PSMD8 is very limited and it has not been cloned in zebrafish till now. In this study, we tried to clone PSMD8 gene in zebrafish, quantify its protein expression level in zebrafish embryos after simulated microgravity and identify its possible function in cell cycle regulation. A rotary cell culture system (RCCS) designed by national aeronautics and apace administration (NASA) of America was used to simulate microgravity. The full-length of psmd8 gene in zebrafish was cloned. Preliminary analysis on its sequence and phylogenetic tree construction were carried out subsequently. Quantitative analysis by western blot showed that PSMD8 protein expression levels were significantly increased 1.18 and 1.22 times after 24-48hpf and 24-72hpf simulated microgravity, respectively. Moreover, a significant delay on zebrafish embryo development was found in simulated-microgravity exposed group. Inhibition of PSMD8 protein in zebrafish embryonic cell lines ZF4 could block cell cycle in G1 phase, which indicated that PSMD8 may play a role in cell cycle regulation. Interestingly, simulated-microgravity could also block ZF4 cell in G1 phase. Whether it is PSMD8 mediated cell cycle regulation result in the zebrafish embryo development delay after simulated microgravity exposure still needs further study. Key Words: PSMD8; Simulated-microgravity; Cell cycle; ZF4 cell line

The effects of simulated space environmental parameters on six commercially available composite materials

NASA Technical Reports Server (NTRS)

Funk, Joan G.; Sykes, George F., Jr.

1989-01-01

The effects of simulated space environmental parameters on microdamage induced by the environment in a series of commercially available graphite-fiber-reinforced composite materials were determined. Composites with both thermoset and thermoplastic resin systems were studied. Low-Earth-Orbit (LEO) exposures were simulated by thermal cycling; geosynchronous-orbit (GEO) exposures were simulated by electron irradiation plus thermal cycling. The thermal cycling temperature range was -250 F to either 200 F or 150 F. The upper limits of the thermal cycles were different to ensure that an individual composite material was not cycled above its glass transition temperature. Material response was characterized through assessment of the induced microcracking and its influence on mechanical property changes at both room temperature and -250 F. Microdamage was induced in both thermoset and thermoplastic advanced composite materials exposed to the simulated LEO environment. However, a 350 F cure single-phase toughened epoxy composite was not damaged during exposure to the LEO environment. The simuated GEO environment produced microdamage in all materials tested.

Capturing Cyclic Variability in EGR Dilute SI Combustion using Multi-Cycle RANS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scarcelli, Riccardo; Sevik, James; Wallner, Thomas

Dilute combustion is an effective approach to increase the thermal efficiency of spark-ignition (SI) internal combustion engines (ICEs). However, high dilution levels typically result in large cycle-to-cycle variations (CCV) and poor combustion stability, therefore limiting the efficiency improvement. In order to extend the dilution tolerance of SI engines, advanced ignition systems are the subject of extensive research. When simulating the effect of the ignition characteristics on CCV, providing a numerical result matching the measured average in-cylinder pressure trace does not deliver useful information regarding combustion stability. Typically Large Eddy Simulations (LES) are performed to simulate cyclic engine variations, since Reynold-Averagedmore » Navier-Stokes (RANS) modeling is expected to deliver an ensemble-averaged result. In this paper it is shown that, when using RANS, the cyclic perturbations coming from different initial conditions at each cycle are not damped out even after many simulated cycles. As a result, multi-cycle RANS results feature cyclic variability. This allows evaluating the effect of advanced ignition sources on combustion stability but requires validation against the entire cycle-resolved experimental dataset. A single-cylinder GDI research engine is simulated using RANS and the numerical results for 20 consecutive engine cycles are evaluated for several operating conditions, including stoichiometric as well as EGR dilute operation. The effect of the ignition characteristics on CCV is also evaluated. Results show not only that multi-cycle RANS simulations can capture cyclic variability and deliver similar trends as the experimental data, but more importantly that RANS might be an effective, lower-cost alternative to LES for the evaluation of ignition strategies for combustion systems that operate close to the stability limit.« less

Multi-Fidelity Simulation of a Turbofan Engine With Results Zoomed Into Mini-Maps for a Zero-D Cycle Simulation

NASA Technical Reports Server (NTRS)

Turner, Mark G.; Reed, John A.; Ryder, Robert; Veres, Joseph P.

2004-01-01

A Zero-D cycle simulation of the GE90-94B high bypass turbofan engine has been achieved utilizing mini-maps generated from a high-fidelity simulation. The simulation utilizes the Numerical Propulsion System Simulation (NPSS) thermodynamic cycle modeling system coupled to a high-fidelity full-engine model represented by a set of coupled 3D computational fluid dynamic (CFD) component models. Boundary conditions from the balanced, steady state cycle model are used to define component boundary conditions in the full-engine model. Operating characteristics of the 3D component models are integrated into the cycle model via partial performance maps generated from the CFD flow solutions using one-dimensional mean line turbomachinery programs. This paper highlights the generation of the high-pressure compressor, booster, and fan partial performance maps, as well as turbine maps for the high pressure and low pressure turbine. These are actually "mini-maps" in the sense that they are developed only for a narrow operating range of the component. Results are compared between actual cycle data at a take-off condition and the comparable condition utilizing these mini-maps. The mini-maps are also presented with comparison to actual component data where possible.

Modeling and Simulation of a Parametrically Resonant Micromirror With Duty-Cycled Excitation.

PubMed

Shahid, Wajiha; Qiu, Zhen; Duan, Xiyu; Li, Haijun; Wang, Thomas D; Oldham, Kenn R

2014-12-01

High frequency large scanning angle electrostatically actuated microelectromechanical systems (MEMS) mirrors are used in a variety of applications involving fast optical scanning. A 1-D parametrically resonant torsional micromirror for use in biomedical imaging is analyzed here with respect to operation by duty-cycled square waves. Duty-cycled square wave excitation can have significant advantages for practical mirror regulation and/or control. The mirror's nonlinear dynamics under such excitation is analyzed in a Hill's equation form. This form is used to predict stability regions (the voltage-frequency relationship) of parametric resonance behavior over large scanning angles using iterative approximations for nonlinear capacitance behavior of the mirror. Numerical simulations are also performed to obtain the mirror's frequency response over several voltages for various duty cycles. Frequency sweeps, stability results, and duty cycle trends from both analytical and simulation methods are compared with experimental results. Both analytical models and simulations show good agreement with experimental results over the range of duty cycled excitations tested. This paper discusses the implications of changing amplitude and phase with duty cycle for robust open-loop operation and future closed-loop operating strategies.

A recurrent neural network for nonlinear optimization with a continuously differentiable objective function and bound constraints.

PubMed

Liang, X B; Wang, J

2000-01-01

This paper presents a continuous-time recurrent neural-network model for nonlinear optimization with any continuously differentiable objective function and bound constraints. Quadratic optimization with bound constraints is a special problem which can be solved by the recurrent neural network. The proposed recurrent neural network has the following characteristics. 1) It is regular in the sense that any optimum of the objective function with bound constraints is also an equilibrium point of the neural network. If the objective function to be minimized is convex, then the recurrent neural network is complete in the sense that the set of optima of the function with bound constraints coincides with the set of equilibria of the neural network. 2) The recurrent neural network is primal and quasiconvergent in the sense that its trajectory cannot escape from the feasible region and will converge to the set of equilibria of the neural network for any initial point in the feasible bound region. 3) The recurrent neural network has an attractivity property in the sense that its trajectory will eventually converge to the feasible region for any initial states even at outside of the bounded feasible region. 4) For minimizing any strictly convex quadratic objective function subject to bound constraints, the recurrent neural network is globally exponentially stable for almost any positive network parameters. Simulation results are given to demonstrate the convergence and performance of the proposed recurrent neural network for nonlinear optimization with bound constraints.

VERA Core Simulator methodology for pressurized water reactor cycle depletion

DOE PAGES

Kochunas, Brendan; Collins, Benjamin; Stimpson, Shane; ...

2017-01-12

This paper describes the methodology developed and implemented in the Virtual Environment for Reactor Applications Core Simulator (VERA-CS) to perform high-fidelity, pressurized water reactor (PWR), multicycle, core physics calculations. Depletion of the core with pin-resolved power and nuclide detail is a significant advance in the state of the art for reactor analysis, providing the level of detail necessary to address the problems of the U.S. Department of Energy Nuclear Reactor Simulation Hub, the Consortium for Advanced Simulation of Light Water Reactors (CASL). VERA-CS has three main components: the neutronics solver MPACT, the thermal-hydraulic (T-H) solver COBRA-TF (CTF), and the nuclidemore » transmutation solver ORIGEN. This paper focuses on MPACT and provides an overview of the resonance self-shielding methods, macroscopic-cross-section calculation, two-dimensional/one-dimensional (2-D/1-D) transport, nuclide depletion, T-H feedback, and other supporting methods representing a minimal set of the capabilities needed to simulate high-fidelity models of a commercial nuclear reactor. Results are presented from the simulation of a model of the first cycle of Watts Bar Unit 1. The simulation is within 16 parts per million boron (ppmB) reactivity for all state points compared to cycle measurements, with an average reactivity bias of <5 ppmB for the entire cycle. Comparisons to cycle 1 flux map data are also provided, and the average 2-D root-mean-square (rms) error during cycle 1 is 1.07%. To demonstrate the multicycle capability, a state point at beginning of cycle (BOC) 2 was also simulated and compared to plant data. The comparison of the cycle 2 BOC state has a reactivity difference of +3 ppmB from measurement, and the 2-D rms of the comparison in the flux maps is 1.77%. Lastly, these results provide confidence in VERA-CS’s capability to perform high-fidelity calculations for practical PWR reactor problems.« less

Observations and statistical simulations of a proposed solar cycle/QBO/weather relationship

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldwin, M.P.; Dunkerton, T.J.

1989-08-01

The 10.7 cm solar flux is observed to be highly correlated with north pole stratospheric temperatures when partitioned according to the phase of the equatorial stratospheric winds (the quasi-biennial oscillation, or QBO). The authors supplement observations with calculations showing that temperatures over most of the northern hemisphere are highly correlated or anticorrelated with north pole temperatures. The observed spatial pattern of solar cycle correlations at high latitudes is shown to be not unique to the solar cycle. The authors present results, similar to the observed solar cycle correlations, with simulated harmonics of various periods replacing the solar cycle. These calculationsmore » demonstrate the correlations at least as high as those for the solar cycle results may be obtained using simulated harmonics.« less

Thermonuclear Bursts with Short Recurrence Times from Neutron Stars Explained by Opacity-driven Convection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keek, L.; Heger, A., E-mail: laurens.keek@nasa.gov

Thermonuclear flashes of hydrogen and helium accreted onto neutron stars produce the frequently observed Type I X-ray bursts. It is the current paradigm that almost all material burns in a burst, after which it takes hours to accumulate fresh fuel for the next burst. In rare cases, however, bursts are observed with recurrence times as short as minutes. We present the first one-dimensional multi-zone simulations that reproduce this phenomenon. Bursts that ignite in a relatively hot neutron star envelope leave a substantial fraction of the fuel unburned at shallow depths. In the wake of the burst, convective mixing events drivenmore » by opacity bring this fuel down to the ignition depth on the observed timescale of minutes. There, unburned hydrogen mixes with the metal-rich ashes, igniting to produce a subsequent burst. We find burst pairs and triplets, similar to the observed instances. Our simulations reproduce the observed fraction of bursts with short waiting times of ∼30%, and demonstrate that short recurrence time bursts are typically less bright and of shorter duration.« less

Thermonuclear Bursts with Short Recurrence Times from Neutron Stars Explained by Opacity-Driven Convection

NASA Technical Reports Server (NTRS)

Keek, L.; Heger, A.

2017-01-01

Thermonuclear flashes of hydrogen and helium accreted onto neutron stars produce the frequently observed Type I X-ray bursts. It is the current paradigm that almost all material burns in a burst, after which it takes hours to accumulate fresh fuel for the next burst. In rare cases, however, bursts are observed with recurrence times as short as minutes. We present the first one-dimensional multi-zone simulations that reproduce this phenomenon. Bursts that ignite in a relatively hot neutron star envelope leave a substantial fraction of the fuel unburned at shallow depths. In the wake of the burst, convective mixing events driven by opacity bring this fuel down to the ignition depth on the observed timescale of minutes. There, unburned hydrogen mixes with the metal-rich ashes, igniting to produce a subsequent burst. We find burst pairs and triplets, similar to the observed instances. Our simulations reproduce the observed fraction of bursts with short waiting times of approximately 30%, and demonstrate that short recurrence time bursts are typically less bright and of shorter duration.

A New Local Bipolar Autoassociative Memory Based on External Inputs of Discrete Recurrent Neural Networks With Time Delay.

PubMed

Zhou, Caigen; Zeng, Xiaoqin; Luo, Chaomin; Zhang, Huaguang

In this paper, local bipolar auto-associative memories are presented based on discrete recurrent neural networks with a class of gain type activation function. The weight parameters of neural networks are acquired by a set of inequalities without the learning procedure. The global exponential stability criteria are established to ensure the accuracy of the restored patterns by considering time delays and external inputs. The proposed methodology is capable of effectively overcoming spurious memory patterns and achieving memory capacity. The effectiveness, robustness, and fault-tolerant capability are validated by simulated experiments.In this paper, local bipolar auto-associative memories are presented based on discrete recurrent neural networks with a class of gain type activation function. The weight parameters of neural networks are acquired by a set of inequalities without the learning procedure. The global exponential stability criteria are established to ensure the accuracy of the restored patterns by considering time delays and external inputs. The proposed methodology is capable of effectively overcoming spurious memory patterns and achieving memory capacity. The effectiveness, robustness, and fault-tolerant capability are validated by simulated experiments.

Vaginal delivery of carboplatin-loaded thermosensitive hydrogel to prevent local cervical cancer recurrence in mice.

PubMed

Wang, Xue; Wang, Jin; Wu, Wenbin; Li, Hongjun

2016-11-01

Local tumor recurrence after cervical cancer surgery remains a clinical problem. Vaginal delivery of thermosensitive hydrogel may be suited to reduce tumor relapse rate with more efficacy and safety. A pilot study was carried out to evaluate the efficacy of carboplatin-loaded poloxamer hydrogel to prevent local recurrence of cervical cancer after surgery. In vivo vaginal retention evaluation of 27% poloxamer hydrogel in mice was proven to be a suitable vaginal drug delivery formulation due to its low gelation temperature. A mimic orthotopic cervical/vaginal cancer recurrence model after surgery was established by injecting murine cervical cancer cell line U14 into the vaginal submucosa to simulate the residual tumor cells infiltrated in the surgical site, followed by drug administration 24 h later to interfere with the formation/recurrence of the tumor. By infusing fluorescein sodium-loaded hydrogel into the vagina of mice, a maximized accumulation of fluorescein sodium (Flu) in the vagina was achieved and few signals were observed in other organs. When used in the prevention of the cervical cancer formation/recurrence in mice, the carboplatin-loaded poloxamer hydrogel exhibited great efficacy and systemic safety. In conclusion, thermosensitive hydrogel presents a simple, practical approach for the local drug delivery via vagina against cervical cancer recurrence.

Lack of effective systemic therapy for recurrent clear cell carcinoma of the ovary.

PubMed

Crotzer, David R; Sun, Charlotte C; Coleman, Robert L; Wolf, Judith K; Levenback, Charles F; Gershenson, David M

2007-05-01

Clear cell carcinoma of the ovary is an aggressive tumor characterized by relative chemoresistance and a poor prognosis. The purpose of this study was to review our experience with recurrent clear cell carcinoma of the ovary to evaluate its responsiveness to systemic cytotoxic and hormonal agents. All patients diagnosed with clear cell carcinoma of the ovary seen at our institution between 1990 and 2002 were identified and their medical records reviewed. Eligibility criteria were: 1) primary diagnosis of clear cell carcinoma of the ovary, 2) measurable recurrent disease, 3) treatment of recurrent disease with 1 or more systemic regimens, and 4) adequate clinical information. End points were clinical response, progression-free survival, and overall survival. Fifty-one patients treated for recurrent clear cell carcinoma were identified. The patients received a total of 105 regimens (344 cycles of therapy). Among patients with platinum-sensitive disease (n=22 regimens), 2 patients (9%) had partial responses to retreatment with carboplatin plus paclitaxel, and 4 (18%) had stable disease. Among patients with platinum-resistant disease (n=83 regimens), only 1 patient (1%) had a partial response - to gemcitabine - and 1 patient had stable disease in response to 2 different regimens-paclitaxel and gemcitabine. The median progression-free survival was 8 months, and the median overall survival was 18 months. Our findings suggest that recurrent clear cell carcinoma of the ovary is particularly chemoresistant. A continued search for more active, targeted agents is warranted.

The annual cycles of phytoplankton biomass

USGS Publications Warehouse

Winder, M.; Cloern, J.E.

2010-01-01

Terrestrial plants are powerful climate sentinels because their annual cycles of growth, reproduction and senescence are finely tuned to the annual climate cycle having a period of one year. Consistency in the seasonal phasing of terrestrial plant activity provides a relatively low-noise background from which phenological shifts can be detected and attributed to climate change. Here, we ask whether phytoplankton biomass also fluctuates over a consistent annual cycle in lake, estuarine-coastal and ocean ecosystems and whether there is a characteristic phenology of phytoplankton as a consistent phase and amplitude of variability. We compiled 125 time series of phytoplankton biomass (chloro-phyll a concentration) from temperate and subtropical zones and used wavelet analysis to extract their dominant periods of variability and the recurrence strength at those periods. Fewer than half (48%) of the series had a dominant 12-month period of variability, commonly expressed as the canonical spring-bloom pattern. About 20 per cent had a dominant six-month period of variability, commonly expressed as the spring and autumn or winter and summer blooms of temperate lakes and oceans. These annual patterns varied in recurrence strength across sites, and did not persist over the full series duration at some sites. About a third of the series had no component of variability at either the six-or 12-month period, reflecting a series of irregular pulses of biomass. These findings show that there is high variability of annual phytoplankton cycles across ecosystems, and that climate-driven annual cycles can be obscured by other drivers of population variability, including human disturbance, aperiodic weather events and strong trophic coupling between phytoplankton and their consumers. Regulation of phytoplankton biomass by multiple processes operating at multiple time scales adds complexity to the challenge of detecting climate-driven trends in aquatic ecosystems where the noise to signal ratio is high. ?? 2010 The Royal Society.

14 CFR 91.1091 - Qualifications: Flight instructors (aircraft) and flight instructors (simulator).

Code of Federal Regulations, 2010 CFR

2010-01-01

... or 135 of this chapter; (2) Has satisfactorily completed the training phases for the aircraft... appropriate training phases for the aircraft, including recurrent training, that are required to serve as a... aircraft, in a flight simulator, or in a flight training device for a particular type, class, or category...

Recurrence of primary extramedullary plasmacytoma in breast both simulating primary breast carcinoma

PubMed Central

Kaviani, Ahmad; Djamali-zavareie, Mansoor; Noparast, Maryam; Keyhani-Rofagha, Sedigheh

2004-01-01

Background Extramedullary myelomas (plasmacytoma) are malignant proliferations of plasma cells in the absence of bone involvement. When they occur in the soft tissue they usually involve the upper respiratory tract and oral cavity. Extramedullary plasmacytomas of breast are uncommon. Case presentation A 70 year-old woman with bilateral breast masses underwent excisional biopsy for suspected primary carcinoma that subsequently proved to be a recurrence from extramedullary plasmacytoma of the mediastinum. This was diagnosed and treated 5-years prior to appearance of breast lumps. Conclusion Though uncommon, considering the possibility of metastatic carcinoma and primary, secondary or recurrent lymphoproliferative disease presenting as a breast mass may avoid unnecessary surgeries. PMID:15339332

MiRNA-362-3p induces cell cycle arrest through targeting of E2F1, USF2 and PTPN1 and is associated with recurrence of colorectal cancer.

PubMed

Christensen, Lise Lotte; Tobiasen, Heidi; Holm, Anja; Schepeler, Troels; Ostenfeld, Marie S; Thorsen, Kasper; Rasmussen, Mads H; Birkenkamp-Demtroeder, Karin; Sieber, Oliver M; Gibbs, Peter; Lubinski, Jan; Lamy, Philippe; Laurberg, Søren; Oster, Bodil; Hansen, Kristian Q; Hagemann-Madsen, Rikke; Byskov, Kristina; Ørntoft, Torben F; Andersen, Claus L

2013-07-01

Colorectal cancer (CRC) is one of the leading causes of cancer deaths in Western countries. A significant number of CRC patients undergoing curatively intended surgery subsequently develop recurrence and die from the disease. MicroRNAs (miRNAs) are aberrantly expressed in cancers and appear to have both diagnostic and prognostic significance. In this study, we identified novel miRNAs associated with recurrence of CRC, and their possible mechanism of action. TaqMan(®) Human MicroRNA Array Set v2.0 was used to profile the expression of 667 miRNAs in 14 normal colon mucosas and 46 microsatellite stable CRC tumors. Four miRNAs (miR-362-3p, miR-570, miR-148 a* and miR-944) were expressed at a higher level in tumors from patients with no recurrence (p<0.015), compared with tumors from patients with recurrence. A significant association with increased disease free survival was confirmed for miR-362-3p in a second independent cohort of 43 CRC patients, using single TaqMan(®) microRNA assays. In vitro functional analysis showed that over-expression of miR-362-3p in colon cancer cell lines reduced cell viability, and proliferation mainly due to cell cycle arrest. E2F1, USF2 and PTPN1 were identified as potential miR-362-3p targets by mRNA profiling of HCT116 cells over-expressing miR-362-3p. Subsequently, these genes were confirmed as direct targets by Luciferase reporter assays and their knockdown in vitro phenocopied the effects of miR-362-3p over-expression. We conclude that miR-362-3p may be a novel prognostic marker in CRC, and hypothesize that the positive effects of augmented miR-362-3p expression may in part be mediated through the targets E2F1, USF2 and PTPN1. Copyright © 2012 UICC.

Phytoremediation of landfill leachate using Populus

Treesearch

Jill A. Zalesny; Ronald S., Jr. Zalesny; Adam H. Wiese; Richard B. Hall; Bart Sexton

2006-01-01

Proper genotype selection is required for successful phytoremediation. We selected eight Populus clones (NC13460, NC14018, DM115, NC14104, NC14106, DN5, NM2, NM6) of four genomic groups after three cycles of phyto-recurrent selection for a field trial that began June 2005 at the Oneida County Landfill in Rhinelander, WI, USA.

Genetic parameters and prediction of breeding values in switchgrass bred for bioenergy

USDA-ARS?s Scientific Manuscript database

Estimating genetic parameters is an essential step in breeding by recurrent selection to maximize genetic gains over time. This study evaluated the effects of selection on genetic variation across two successive cycles (C1 and C2) of a ‘Summer’x‘Kanlow’ switchgrass (Panicum virgatum L.) population. ...

A novel nonlinear adaptive filter using a pipelined second-order Volterra recurrent neural network.

PubMed

Zhao, Haiquan; Zhang, Jiashu

2009-12-01

To enhance the performance and overcome the heavy computational complexity of recurrent neural networks (RNN), a novel nonlinear adaptive filter based on a pipelined second-order Volterra recurrent neural network (PSOVRNN) is proposed in this paper. A modified real-time recurrent learning (RTRL) algorithm of the proposed filter is derived in much more detail. The PSOVRNN comprises of a number of simple small-scale second-order Volterra recurrent neural network (SOVRNN) modules. In contrast to the standard RNN, these modules of a PSOVRNN can be performed simultaneously in a pipelined parallelism fashion, which can lead to a significant improvement in its total computational efficiency. Moreover, since each module of the PSOVRNN is a SOVRNN in which nonlinearity is introduced by the recursive second-order Volterra (RSOV) expansion, its performance can be further improved. Computer simulations have demonstrated that the PSOVRNN performs better than the pipelined recurrent neural network (PRNN) and RNN for nonlinear colored signals prediction and nonlinear channel equalization. However, the superiority of the PSOVRNN over the PRNN is at the cost of increasing computational complexity due to the introduced nonlinear expansion of each module.

[Longitudinal analysis of vaginal microbiota in women with recurrent vulvovaginal candidiasis].

PubMed

Ma, Xiao; Cai, Hui-Hua; He, Yan; Zheng, Hui-Min; Kang, Ling; Zhou, Hong-Wei; Liu, Mu-Biao

2016-02-20

To investigate the vaginal flora in patients with recurrent vulvovaginal candidiasis (RVVC). Vaginal swabs were collected at different time points from 6 RVVC patients and 5 healthy women of child-bearing age. The dynamic changes, microbiota composition, alpha diversity and beta diversity in the two groups were assessed by analyzing the 16S rRNA V4 hypervariable region amplified from the total genomic DNA from the swabs. Lactobacillus was the predominant species in healthy women with similar proportions of L.iners and L.crispatus; small proportions of Gardnerella, Prevotella and other genus were also detected. In some healthy women, the vaginal flora showed a high relative abundance of anaerobic bacteria such as Gardnerella, Prevotella, Atopobium, Sneathia. Compared with the healthy women, patients with RVVC showed a significantly reduced diversity of vaginal flora, where L.iners was the predominant species and the content of L.crispatus decreased significantly. In healthy women, the vaginal flora fluctuated with the menstrual cycle, and the fluctuation was the most prominent during menstruation; the dominant species either alternated regularly or maintain an absolute superiority in the menstrual cycle. The vaginal flora showed attenuated fluctuation in women with RVVC, were highly conserved within the menstrual cycle, and maintained a similar composition in the episodes and intermittent periods. The vaginal flora of RVVC patients do not undergo regular variations with the menstrual cycle and shows a similar composition between the episodes and intermittent periods. Promoting the production of L.iners or inhibiting the colonization of L.crispatus to restore the composition of the vaginal flora may help in the treatment of RVVC.

Active, capable, and potentially active faults - a paleoseismic perspective

USGS Publications Warehouse

Machette, M.N.

2000-01-01

Maps of faults (geologically defined source zones) may portray seismic hazards in a wide range of completeness depending on which types of faults are shown. Three fault terms - active, capable, and potential - are used in a variety of ways for different reasons or applications. Nevertheless, to be useful for seismic-hazards analysis, fault maps should encompass a time interval that includes several earthquake cycles. For example, if the common recurrence in an area is 20,000-50,000 years, then maps should include faults that are 50,000-100,000 years old (two to five typical earthquake cycles), thus allowing for temporal variability in slip rate and recurrence intervals. Conversely, in more active areas such as plate boundaries, maps showing faults that are <10,000 years old should include those with at least 2 to as many as 20 paleoearthquakes. For the International Lithosphere Programs' Task Group II-2 Project on Major Active Faults of the World our maps and database will show five age categories and four slip rate categories that allow one to select differing time spans and activity rates for seismic-hazard analysis depending on tectonic regime. The maps are accompanied by a database that describes evidence for Quaternary faulting, geomorphic expression, and paleoseismic parameters (slip rate, recurrence interval and time of most recent surface faulting). These maps and databases provide an inventory of faults that would be defined as active, capable, and potentially active for seismic-hazard assessments.

Temozolomide is an active agent in children with recurrent medulloblastoma/primitive neuroectodermal tumor: an Italian multi-institutional phase II trial.

PubMed

Cefalo, Graziella; Massimino, Maura; Ruggiero, Antonio; Barone, Giuseppe; Ridola, Vita; Spreafico, Filippo; Potepan, Paolo; Abate, Massimo E; Mascarin, Maurizio; Garrè, Maria Luisa; Perilongo, Giorgio; Madon, Enrico; Colosimo, Cesare; Riccardi, Riccardo

2014-05-01

The aim of this study was to assess the objective response rate (ORR) of children and young adults with recurrent medulloblastoma/primitive neuroectodermal tumor (MB/PNET) treated with temozolomide (TMZ). The secondary purpose was to analyze the toxicity profile of TMZ when administered orally for 5 days in 3 divided daily doses every 28 days. Forty-two patients with recurrent MB/PNET, aged 21 years and younger, were recruited. Patients were treated with oral TMZ. Starting doses ranged from 120 to 200 mg/m(2)/day based on previous treatments. A craniospinal MRI was performed prior to the first cycle of TMZ and following every 2 cycles of treatment. Median age was 10 years (range, 2-21 years). Forty of 42 patients were assessed for response and toxicity. The objective response rate was 42.5%: 6 patients achieved a complete response, 11 had a partial response, and 10 had stable disease. Progression-free survival rates for all patients at 6 and 12 months were 30% and 7.5%, respectively. Their median overall survival rates at 6 and 12 months were 42.5% and 17.5%, respectively. No major extrahematological effects or life-threatening events were reported. The most common grade 3/4 toxicity included thrombocytopenia (17.5%), neutropenia (7.5%), and anemia (2.5%). TMZ proved to be an effective agent in children and young adults with MB/PNET, heavily pre-treated, with a tolerable toxicity profile.

Adjuvant chemotherapy for locally advanced urothelial carcinoma: an overview of the USC experience.

PubMed

Dorff, Tanya B; Tsao-Wei, Denice; Miranda, Gus; Skinner, Donald G; Stein, John P; Quinn, David I

2009-02-01

To describe the tolerability of two chemotherapy regimens, gemcitabine and cisplatin (GC) and methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) for adjuvant treatment of patients with locally advanced urothelial cancer after radical cystectomy. The USC Department of Urology bladder cancer database was searched for subjects who received adjuvant chemotherapy following cystectomy for transitional cell carcinoma with extravesical and/or lymph node involvement, yielding 187 cases. Clinical details regarding toxicity, number of cycles administered, and cancer outcome were analyzed. The majority of subjects had lymph node involvement (70%). Sixty-eight percent of subjects received MVAC and 32% received GC, the latter regimen was predominant after 2000. Fifty-six percent of subjects received all four planned cycles (51% GC and 58% MVAC). With a median follow-up of 11.2 years (range 1.9-19.6), 96 patients (51%) have suffered a relapse, with no significant difference between chemotherapy regimens. Median time to recurrence for the population was 3.7 years and median overall survival is 4.6 years (3.0-9.3). The median time from recurrence to death was 6.7 months and was not significantly different between MVAC and GC. Both MVAC and GC are tolerated after cystectomy for advanced urothelial carcinoma. A significant proportion of high-risk patients survive, free of disease, beyond 10 years. At recurrence, patients previously treated with adjuvant chemotherapy have a survival that appears much shorter than patients who develop metastases in the absence of this exposure, suggesting resistance to salvage chemotherapy.

A probabilistic model for analysing the effect of performance levels on visual behaviour patterns of young sailors in simulated navigation.

PubMed

Manzanares, Aarón; Menayo, Ruperto; Segado, Francisco; Salmerón, Diego; Cano, Juan Antonio

2015-01-01

The visual behaviour is a determining factor in sailing due to the influence of the environmental conditions. The aim of this research was to determine the visual behaviour pattern in sailors with different practice time in one star race, applying a probabilistic model based on Markov chains. The sample of this study consisted of 20 sailors, distributed in two groups, top ranking (n = 10) and bottom ranking (n = 10), all of them competed in the Optimist Class. An automated system of measurement, which integrates the VSail-Trainer sail simulator and the Eye Tracking System(TM) was used. The variables under consideration were the sequence of fixations and the fixation recurrence time performed on each location by the sailors. The event consisted of one of simulated regatta start, with stable conditions of wind, competitor and sea. Results show that top ranking sailors perform a low recurrence time on relevant locations and higher on irrelevant locations while bottom ranking sailors make a low recurrence time in most of the locations. The visual pattern performed by bottom ranking sailors is focused around two visual pivots, which does not happen in the top ranking sailor's pattern. In conclusion, the Markov chains analysis has allowed knowing the visual behaviour pattern of the top and bottom ranking sailors and its comparison.

Parallel methodology to capture cyclic variability in motored engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ameen, Muhsin M.; Yang, Xiaofeng; Kuo, Tang-Wei

2016-07-28

Numerical prediction of of cycle-to-cycle variability (CCV) in SI engines is extremely challenging for two key reasons: (i) high-fidelity methods such as large eddy simulation (LES) are require to accurately capture the in-cylinder turbulent flowfield, and (ii) CCV is experienced over long timescales and hence the simulations need to be performed for hundreds of consecutive cycles. In this study, a new methodology is proposed to dissociate this long time-scale problem into several shorter time-scale problems, which can considerably reduce the computational time without sacrificing the fidelity of the simulations. The strategy is to perform multiple single-cycle simulations in parallel bymore » effectively perturbing the simulation parameters such as the initial and boundary conditions. It is shown that by perturbing the initial velocity field effectively based on the intensity of the in-cylinder turbulence, the mean and variance of the in-cylinder flowfield is captured reasonably well. Adding perturbations in the initial pressure field and the boundary pressure improves the predictions. It is shown that this new approach is able to give accurate predictions of the flowfield statistics in less than one-tenth of time required for the conventional approach of simulating consecutive engine cycles.« less

Rapid methods for radionuclide contaminant transport in nuclear fuel cycle simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huff, Kathryn

Here, nuclear fuel cycle and nuclear waste disposal decisions are technologically coupled. However, current nuclear fuel cycle simulators lack dynamic repository performance analysis due to the computational burden of high-fidelity hydrolgic contaminant transport models. The Cyder disposal environment and repository module was developed to fill this gap. It implements medium-fidelity hydrologic radionuclide transport models to support assessment appropriate for fuel cycle simulation in the Cyclus fuel cycle simulator. Rapid modeling of hundreds of discrete waste packages in a geologic environment is enabled within this module by a suite of four closed form models for advective, dispersive, coupled, and idealized con-more » taminant transport: a Degradation Rate model, a Mixed Cell model, a Lumped Parameter model, and a 1-D Permeable Porous Medium model. A summary of the Cyder module, its timestepping algorithm, and the mathematical models implemented within it are presented. Additionally, parametric demonstrations simulations performed with Cyder are presented and shown to demonstrate functional agreement with parametric simulations conducted in a standalone hydrologic transport model, the Clay Generic Disposal System Model developed by the Used Fuel Disposition Campaign Department of Energy Office of Nuclear Energy.« less

Rapid methods for radionuclide contaminant transport in nuclear fuel cycle simulation

DOE PAGES

Huff, Kathryn

2017-08-01

Here, nuclear fuel cycle and nuclear waste disposal decisions are technologically coupled. However, current nuclear fuel cycle simulators lack dynamic repository performance analysis due to the computational burden of high-fidelity hydrolgic contaminant transport models. The Cyder disposal environment and repository module was developed to fill this gap. It implements medium-fidelity hydrologic radionuclide transport models to support assessment appropriate for fuel cycle simulation in the Cyclus fuel cycle simulator. Rapid modeling of hundreds of discrete waste packages in a geologic environment is enabled within this module by a suite of four closed form models for advective, dispersive, coupled, and idealized con-more » taminant transport: a Degradation Rate model, a Mixed Cell model, a Lumped Parameter model, and a 1-D Permeable Porous Medium model. A summary of the Cyder module, its timestepping algorithm, and the mathematical models implemented within it are presented. Additionally, parametric demonstrations simulations performed with Cyder are presented and shown to demonstrate functional agreement with parametric simulations conducted in a standalone hydrologic transport model, the Clay Generic Disposal System Model developed by the Used Fuel Disposition Campaign Department of Energy Office of Nuclear Energy.« less

A Turbine Based Combined Cycle Engine Inlet Model and Mode Transition Simulation Based on HiTECC Tool

NASA Technical Reports Server (NTRS)

Csank, Jeffrey; Stueber, Thomas

2012-01-01

An inlet system is being tested to evaluate methodologies for a turbine based combined cycle propulsion system to perform a controlled inlet mode transition. Prior to wind tunnel based hardware testing of controlled mode transitions, simulation models are used to test, debug, and validate potential control algorithms. One candidate simulation package for this purpose is the High Mach Transient Engine Cycle Code (HiTECC). The HiTECC simulation package models the inlet system, propulsion systems, thermal energy, geometry, nozzle, and fuel systems. This paper discusses the modification and redesign of the simulation package and control system to represent the NASA large-scale inlet model for Combined Cycle Engine mode transition studies, mounted in NASA Glenn s 10-foot by 10-foot Supersonic Wind Tunnel. This model will be used for designing and testing candidate control algorithms before implementation.

A Turbine Based Combined Cycle Engine Inlet Model and Mode Transition Simulation Based on HiTECC Tool

NASA Technical Reports Server (NTRS)

Csank, Jeffrey T.; Stueber, Thomas J.

2012-01-01

An inlet system is being tested to evaluate methodologies for a turbine based combined cycle propulsion system to perform a controlled inlet mode transition. Prior to wind tunnel based hardware testing of controlled mode transitions, simulation models are used to test, debug, and validate potential control algorithms. One candidate simulation package for this purpose is the High Mach Transient Engine Cycle Code (HiTECC). The HiTECC simulation package models the inlet system, propulsion systems, thermal energy, geometry, nozzle, and fuel systems. This paper discusses the modification and redesign of the simulation package and control system to represent the NASA large-scale inlet model for Combined Cycle Engine mode transition studies, mounted in NASA Glenn s 10- by 10-Foot Supersonic Wind Tunnel. This model will be used for designing and testing candidate control algorithms before implementation.

Rapid palliation of symptoms with platinum-based chemotherapy plus cetuximab in recurrent oral cancer: a case report

PubMed Central

2010-01-01

Background Symptom control is an important consideration in the choice of treatment for patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN). Patients who demonstrate objective tumour responses to platinum-based chemotherapy are more likely to have symptom relief than those who do not have such responses. A phase III trial (EXTREME) showed that adding the epidermal growth factor receptor (EGFR)-targeting IgG1 monoclonal antibody cetuximab to first-line platinum-based chemotherapy significantly prolongs progression-free and overall survival and increases response rate compared with platinum-based chemotherapy alone. We report here the case of a 60-year old female with recurrent squamous cell carcinoma of the gum who had rapid palliation of symptoms and reduction of facial disease mass following treatment with a combination of carboplatin/5-fluorouracil (5-FU) and cetuximab. Case presentation The patient was diagnosed with T4N0 M0 disease of the oral cavity in November 2006 and underwent surgery, with R0 resection, followed by adjuvant radiotherapy and concomitant cisplatin chemotherapy. Around 3 months later, the disease recurred and the patient had severe pain (9/10 on a visual pain scale), marked facial oedema and a palpable facial mass of 89 mm. The patient received 4 21-day cycles of carboplatin (AUC 5), 5-FU (1,000 mg/m2/day for 4 days) and cetuximab (400 mg/m2 initial dose followed by subsequently weekly doses of 250 mg/m2), with continuation of cetuximab monotherapy at the end of this time, and pain relief with topical fentanyl and oral morphine. After 7 days of treatment, pain had reduced to 2/10, with discontinuation of morphine after 4 days, and the facial mass had reduced to 70 mm. After 2 cycles of treatment, the facial mass had decreased to 40 mm. After 3 cycles of treatment, pain and facial oedema had resolved completely and a cervical computed tomography scan showed a marked reduction in tumour mass. Cetuximab monotherapy was continued uninterrupted for 7 months. Conclusion This case illustrates the rapid reduction of tumour mass and disease-associated pain and oedema that can be achieved with a combination of platinum-based chemotherapy and cetuximab in recurrent and/or metastatic SCCHN. PMID:20181021

Temporal Variation of the Rotation of the Solar Mean Magnetic Field

NASA Astrophysics Data System (ADS)

Xie, J. L.; Shi, X. J.; Xu, J. C.

2017-04-01

Based on continuous wavelet transformation analysis, the daily solar mean magnetic field (SMMF) from 1975 May 16 to 2014 July 31 is analyzed to reveal its rotational behavior. Both the recurrent plot in Bartels form and the continuous wavelet transformation analysis show the existence of rotational modulation in the variation of the daily SMMF. The dependence of the rotational cycle lengths on solar cycle phase is also studied, which indicates that the yearly mean rotational cycle lengths generally seem to be longer during the rising phase of solar cycles and shorter during the declining phase. The mean rotational cycle length for the rising phase of all of the solar cycles in the considered time is 28.28 ± 0.67 days, while for the declining phase it is 27.32 ± 0.64 days. The difference of the mean rotational cycle lengths between the rising phase and the declining phase is 0.96 days. The periodicity analysis, through the use of an auto-correlation function, indicates that the rotational cycle lengths have a significant period of about 10.1 years. Furthermore, the cross-correlation analysis indicates that there exists a phase difference between the rotational cycle lengths and solar activity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, J. L.; Shi, X. J.; Xu, J. C., E-mail: xiejinglan@ynao.ac.cn

Based on continuous wavelet transformation analysis, the daily solar mean magnetic field (SMMF) from 1975 May 16 to 2014 July 31 is analyzed to reveal its rotational behavior. Both the recurrent plot in Bartels form and the continuous wavelet transformation analysis show the existence of rotational modulation in the variation of the daily SMMF. The dependence of the rotational cycle lengths on solar cycle phase is also studied, which indicates that the yearly mean rotational cycle lengths generally seem to be longer during the rising phase of solar cycles and shorter during the declining phase. The mean rotational cycle lengthmore » for the rising phase of all of the solar cycles in the considered time is 28.28 ± 0.67 days, while for the declining phase it is 27.32 ± 0.64 days. The difference of the mean rotational cycle lengths between the rising phase and the declining phase is 0.96 days. The periodicity analysis, through the use of an auto-correlation function, indicates that the rotational cycle lengths have a significant period of about 10.1 years. Furthermore, the cross-correlation analysis indicates that there exists a phase difference between the rotational cycle lengths and solar activity.« less

Studies of Fault Interactions and Regional Seismicity Using Numerical Simulations

NASA Astrophysics Data System (ADS)

Yikilmaz, Mehmet Burak

Numerical simulations are routinely used for weather and climate forecasting. It is desirable to simulate regional seismicity for seismic hazard analysis. One such simulation tool is the Virtual California earthquake simulator. We have used Virtual California (VC) to study various aspects of fault interaction and analyzed the statistics of earthquake recurrence times and magnitudes generated synthetically. The first chapter of this dissertation investigates the behavior of seismology simulations using three relatively simple models involving a straight strike-slip fault. We show that a series of historical earthquakes observed along the Nankai Trough in Japan exhibit similar patterns to those obtained in our model II. In the second chapter we utilize Virtual California to study regional seismicity in northern California. We generate synthetic catalogs of seismicity using a composite simulation. We use these catalogs to analyze frequency-magnitude and recurrence interval statistics on both a regional and fault specific level and compare our modeled rates of seismicity and spatial variability with observations. The final chapter explores the jump distance for a propagating rupture over a stepping strike-slip fault. Our study indicates that between 2.5 and 5.5 km of the separation distance, the percentage of events that jump from one fault to the next decreases significantly. We find that these step-over distance values are in good agreement with geologically observed values.

Phase I Trial and Pharmacokinetic Study of Lexatumumab in Pediatric Patients With Solid Tumors

PubMed Central

Merchant, Melinda S.; Geller, James I.; Baird, Kristin; Chou, Alexander J.; Galli, Susana; Charles, Ava; Amaoko, Martha; Rhee, Eunice H.; Price, Anita; Wexler, Leonard H.; Meyers, Paul A.; Widemann, Brigitte C.; Tsokos, Maria; Mackall, Crystal L.

2012-01-01

Purpose Lexatumumab is an agonistic, fully human monoclonal antibody against tumor necrosis factor–related apoptosis-inducing ligand receptor 2 with preclinical evidence of activity in pediatric solid tumors. Patients and Methods This phase I dose-escalation study examined the safety, tolerability, pharmacokinetics, and immunogenicity of lexatumumab at doses up to, but not exceeding, the adult maximum-tolerated dose (3, 5, 8, and 10 mg/kg), administered once every 2 weeks to patients age ≤ 21 years with recurrent or progressive solid tumors. Results Twenty-four patients received a total of 56 cycles of lexatumumab over all four planned dose levels. One patient had grade 2 pericarditis consistent with radiation recall, and one patient developed grade 3 pneumonia with hypoxia during the second cycle. Five patients experienced stable disease for three to 24 cycles. No patients experienced complete or partial response, but several showed evidence of antitumor activity, including one patient with recurrent progressive osteosarcoma who experienced resolution of clinical symptoms and positron emission tomography activity, ongoing more than 1 year off therapy. One patient with hepatoblastoma showed a dramatic biomarker response. Conclusion Pediatric patients tolerate 10 mg/kg of lexatumumab administered once every 14 days, the maximum-tolerated dose identified in adults. The drug seems to mediate some clinical activity in pediatric solid tumors and may work with radiation to enhance antitumor effects. PMID:23071222

High expression of Polycomb group protein EZH2 predicts poor survival in salivary gland adenoid cystic carcinoma.

PubMed

Vékony, H; Raaphorst, F M; Otte, A P; van Lohuizen, M; Leemans, C R; van der Waal, I; Bloemena, E

2008-06-01

The prognosis of adenoid cystic carcinoma (ACC), a malignant salivary gland tumour, depends on clinicopathological parameters. To decipher the biological behaviour of ACC, and to identify patients at risk of developing metastases, additional markers are needed. Expression of the cell cycle proteins p53, cyclin D1, p16(INK4a), E2F1 and Ki-67, together with the Polycomb group (PcG) proteins BMI-1, MEL-18, EZH2 and EED was investigated immunohistochemically 21 formalin-fixed, paraffin-embedded primary ACCs in relation to tumour characteristics. ACC revealed significantly increased expression of the cell cycle proteins compared to normal salivary tissue (n = 17). Members of the two PcG complexes displayed mutually exclusive expression in normal salivary gland tissue, with BMI-1 and MEL-18 being abundantly present. In ACC, this expression pattern was disturbed, with EZH2 and EED showing significantly increased expression levels. In univariate analysis, presence of recurrence, poor differentiation and high EZH2 levels (>25% immunopositivity) significantly correlated with unfavourable outcome. ACCs with high proliferative rate (>25% Ki-67 immunopositivity) significantly correlated with high levels of EZH2 and p16. Only the development of recurrence was an independent prognostic factor of survival in multivariate analysis. Expression of PcG complexes and of essential cell cycle proteins is highly deregulated in ACC. Also, EZH2 expression has prognostic relevance in this malignancy.

A late phase II study of RP56976 (docetaxel) in patients with advanced or recurrent breast cancer.

PubMed Central

Adachi, I.; Watanabe, T.; Takashima, S.; Narabayashi, M.; Horikoshi, N.; Aoyama, H.; Taguchi, T.

1996-01-01

A late phase II clinical trial of RP56976 (docetaxel), derived from Taxus baccata was performed to evaluate anti-tumour activity, time to progression and clinical toxicity in patients with advanced or recurrent breast cancer. The patients, between 15 and 80 years old with performance status (PS) of 0-2, received at least two cycles of docetaxel 60 mg m-2 intravenously at 3-4 week intervals. Of the 81 patients enrolled, the 72 eligible for the study were given a total of 327 cycles, with a median of four cycles each. Five patients obtained a complete response (CR) and 27 a partial response (PR); the response rate (RR) was 44.4% (95% confidence interval 32.7-56.6%). A relatively high RR of 9/28 (32.1%) was observed in patients who had received prior chemotherapy involving anthracyclines. The dose-limiting toxicity was grade 3-4 leucocytopenia or neutropenia, found in 78.9% and 85.9% patients respectively. Other severe (grade > 3) toxicities included alopecia (38%), anorexia (18.3%), nausea/vomiting (11.3%), and fatigue (9.9%). Hypersensitivity reactions, oedema and skin toxicity were not severe and were reversible. One therapy-related death occurred 10 days after the initial dose was given. These findings indicate that docetaxel has potent activity against metastatic breast cancer, and that the dose of 60 mg m-2 is safe. PMID:8546908

U-Th and 10Be constraints on sediment recycling in proglacial settings, Lago Buenos Aires, Patagonia

NASA Astrophysics Data System (ADS)

Cogez, Antoine; Herman, Frédéric; Pelt, Éric; Reuschlé, Thierry; Morvan, Gilles; Darvill, Christopher M.; Norton, Kevin P.; Christl, Marcus; Märki, Lena; Chabaux, François

2018-03-01

The estimation of sediment transfer times remains a challenge to our understanding of sediment budgets and the relationships between erosion and climate. Uranium (U) and thorium (Th) isotope disequilibria offer a means of more robustly constraining sediment transfer times. Here, we present new uranium and thorium disequilibrium data for a series of nested moraines around Lago Buenos Aires in Argentine Patagonia. The glacial chronology for the area is constrained using in situ cosmogenic 10Be analysis of glacial outwash. Sediment transfer times within the periglacial domain were estimated by comparing the deposition ages of moraines to the theoretical age of sediment production, i.e., the comminution age inferred from U disequilibrium data and recoil loss factor estimates. Our data show first that the classical comminution age approach must include weathering processes accounted for by measuring Th disequilibrium. Second, our combined data suggest that the pre-deposition history of the moraine sediments is not negligible, as evidenced by the large disequilibrium of the youngest moraines despite the equilibrium of the corresponding glacial flour. Monte Carlo simulations suggest that weathering was more intense before the deposition of the moraines and that the transfer time of the fine sediments to the moraines was on the order of 100-200 kyr. Long transfer times could result from a combination of long sediment residence times in the proglacial lake (recurrence time of a glacial cycle) and the remobilization of sediments from moraines deposited during previous glacial cycles. 10Be data suggest that some glacial cycles are absent from the preserved moraine record (seemingly every second cycle), supporting a model of reworking moraines and/or fluctuations in the extent of glacial advances. The chronological pattern is consistent with the U-Th disequilibrium data and the 100-200 kyr transfer time. This long transfer time raises the question of the proportion of freshly eroded sediments that escape (or not) the proglacial environments during glacial periods.

A phase 1/2 dose-finding, safety, and activity study of cabazitaxel in pediatric patients with refractory solid tumors including tumors of the central nervous system.

PubMed

Manley, Peter E; Trippett, Tanya; Smith, Amy A; Macy, Margaret E; Leary, Sarah E S; Boklan, Jessica; Cohen, Kenneth J; Goldman, Stewart; Kilburn, Lindsay B; Dhall, Girish; Devin, Jeanne; Herzog, Cynthia E; Partap, Sonia; Fauchet, Floris; Badreddine, Emmy; Bernard, John P; Chi, Susan N

2018-05-11

This phase 1/2 study (NCT01751308) evaluated cabazitaxel in pediatric patients. Phase 1 determined the maximum tolerated dose (MTD) in patients with recurrent/refractory solid tumors, including central nervous system (CNS) tumors. Phase 2 evaluated activity in pediatric recurrent high-grade glioma (HGG) or diffuse intrinsic pontine glioma (DIPG). In phase 1, a 3 + 3 dose-escalation study design was followed. Cabazitaxel was administered at a starting dose of 20 mg/m 2 . Dose-limiting toxicities (DLTs) during cycle 1 were assessed to determine the MTD. Tumor response and cabazitaxel pharmacokinetics were also assessed. In phase 2, patients received cabazitaxel at the MTD determined in phase 1. Tumor responses were assessed every 9 weeks (modified Response Assessment in Neuro-oncology criteria). Progression-free survival and cabazitaxel pharmacokinetics were evaluated, and overall survival was estimated. In phase 1, 23 patients were treated, including 19 with CNS tumors. One patient had a partial response; five had stable disease for >3 cycles. Common adverse events included fatigue, diarrhea, nausea and vomiting, febrile neutropenia, and hypersensitivity reactions. Two of three DLTs (febrile neutropenia) occurred with a dose of 35 mg/m 2 ; the MTD was 30 mg/m 2 . Slightly higher cabazitaxel clearance was observed compared with adult trials. In phase 2, 16 patients (eight HGG and eight DIPG) were enrolled; 11 were evaluable for response and five withdrew (three due to anaphylaxis). All 11 patients progressed within four cycles. No responses were observed; the study was stopped due to futility. The safety profile of cabazitaxel was consistent with previous studies. The MTD (30 mg/m 2 ) was higher than the adult MTD. Cabazitaxel did not demonstrate activity in recurrent/refractory HGG or DIPG. © 2018 Wiley Periodicals, Inc.

[Diagnosis and surgical treatment of Castleman's disease].

PubMed

Ma, Shi-hong; Liu, Qin-jiang; Zhang, You-cheng; Yang, Rong

2011-04-26

To explore the clinical features and surgical treatment of tumors associated with Castleman's disease (CD). The clinical profiles of 19 patients with neck giant lymph node hyperplasia were analyzed retrospectively. There were 8 males and 11 females with a median age of 40 years old (range: 7 - 74). The tumor locations were neck (n = 12), neck & mediastinal cavity (n = 2), axillary fossa (n = 2), retroperitoneal area (n = 2) and abdominal cavity (n = 1). Eighteen of them underwent surgical resection of tumor or lymph nodes. All were diagnosed as CD by pathological examinations. There were 16 localized CD (LCD) including hyaline vascular type (HV type, n = 11), mixed type (mix type, n = 4) and plasma cell type-Hodgkin's disease (n = 1). Among 3 multicentric CD (MCD), there were 2 case of plasma cell type (PC type) and 1 case of mixed type (mix type). Long-term survival was achieved in 19 cases among which 1 case of plasma cell type MCD survived for 5 years and underwent a second operation and postoperative chemotherapy of CVP (cyclophosphamide, vincristine & prednisone) regimen for 3 cycles due to recurrence in 2 years and 1 case of plasma cell type LCD-Hodgkin's disease survived for 15 months and underwent a second operation and postoperative chemotherapy of ABVD (adriamycin, bleomycin, vinblastine & dacarbazine)regimen for 6 cycles due to recurrence in 6 months. One case of plasma cell type MCD in abdominal cavity on chemotherapy of CHOP (cyclophosphamide, hydroxydaunorubicin, vincristine & prednisone) regimen for 6 cycles was discharged after a successful management of intestinal obstruction. The major clinical symptom of CD is a gradually enlarging painless mass. Surgical resection of tumor remains the first-line treatment for localized CD and the prognosis is excellent. Multicentric and plasma cell type CDs are prone to recurrence and transformation to lymphoma. And their first-line therapeutic should encompass multi-modality regimens of surgery and adjuvant chemotherapy. However, the clinical prognosis is still poor.

A phase 1 study of eribulin mesylate (E7389), a novel microtubule-targeting chemotherapeutic agent, in children with refractory or recurrent solid tumors: A Children's Oncology Group Phase 1 Consortium study (ADVL1314).

PubMed

Schafer, Eric S; Rau, Rachel E; Berg, Stacey; Liu, Xiaowei; Minard, Charles G; D'Adamo, David; Scott, Rachael; Reyderman, Larisa; Martinez, Gresel; Devarajan, Sandhya; Reid, Joel M; Fox, Elizabeth; Weigel, Brenda J; Blaney, Susan M

2018-05-02

Eribulin mesylate is a novel anticancer agent that inhibits microtubule growth, without effects on shortening, and promotes nonproductive tubulin aggregate formation. We performed a phase 1 trial to determine the dose-limiting toxicities (DLTs), maximum tolerated or recommended phase 2 dose (MTD/RP2D), and pharmacokinetics (PK) of eribulin in children with refractory or recurrent solid (excluding central nervous system) tumors. Eribulin was administered intravenously on days 1 and 8 in 21-day cycles. Three dose levels (1.1, 1.4, and 1.8 mg/m 2 /dose) were evaluated using the rolling six design with additional patients enrolled into a PK expansion cohort at the MTD. PK samples were obtained following the day 1, cycle 1 dose. Twenty-three patients, ages 3-17 (median 14) years were enrolled; 20 were evaluable for toxicity. DLTs occurred in 0/6 and 1/6 subjects at the 1.1 and 1.4 mg/m 2 /dose, respectively. One subject at the 1.4 mg/m 2 /dose had grade 4 neutropenia and grade 3 fatigue. At the 1.8 mg/m 2 /dose, 2/5 subjects experienced dose-limiting (grade 4) neutropenia. Grade 3/4 non-DLTs included lymphopenia and hypokalemia, while low-grade toxicities included anorexia and nausea. No episodes of grade > 2 corrected QT interval prolongation or peripheral neuropathy were reported. Eribulin pharmacokinetic parameters were highly variable; the median elimination half-life was 39.6 (range 24.2-96.4) hr. A partial response was observed in one patient (Ewing sarcoma). Eribulin was well tolerated in children with refractory or recurrent solid tumors with neutropenia identified as the primary DLT. The RP2D of eribulin is 1.4 mg/m 2 /dose on days 1 and 8 of a 21-day cycle. © 2018 Wiley Periodicals, Inc.

Phase I trial of p28 (NSC745104), a non-HDM2-mediated peptide inhibitor of p53 ubiquitination in pediatric patients with recurrent or progressive central nervous system tumors: A Pediatric Brain Tumor Consortium Study

PubMed Central

Goldman, Stewart; Yamada, Tohru; Beattie, Craig W.; Bressler, Linda; Pacini, Michael; Pollack, Ian F.; Fisher, Paul Graham; Packer, Roger J.; Dunkel, Ira J.; Dhall, Girish; Wu, Shengjie; Onar, Arzu; Boyett, James M.; Fouladi, Maryam

2016-01-01

Background p53 is a promising target in human cancer. p28 is a cell-penetrating peptide that preferentially enters cancer cells and binds to both wild-type and mutant p53 protein, inhibiting COP1-mediated ubiquitination and proteasomal degradation. This results in increased levels of p53, which induces cell cycle arrest at G2/M. We conducted a phase I study to determine the maximum-tolerated dose (MTD) and describe the dose-limiting toxicities (DLTs) and pharmacokinetics (PKs) of p28 in children. Methods Children aged 3–21 years with recurrent or progressive central nervous system tumors were eligible. Intravenous p28 was administered 3 times weekly for 4 consecutive weeks of a 6-week cycle at 4.16 mg/kg/dose (the adult recommended phase II dose) using a rolling-6 study design. Expression status of p53 was characterized by immunohistochemistry, and serum PK parameters were established on the second dose. Results Of the 18 eligible patients enrolled in the study, 12 completed the DLT monitoring period and were evaluable for toxicity. p28 was well-tolerated; 7 participants received ≥2 courses, and the most common adverse event attributed to the drug was transient grade 1 infusion-related reaction. PK analysis revealed a profile similar to adults; however, an increased area under the curve was observed in pediatric patients. High p53 expression in tumor cell nuclei was observed in 6 of 12 available tissue samples. There were no objective responses; 2 participants remained stable on the study for >4 cycles. Conclusions This phase I study demonstrated that p28 is well-tolerated in children with recurrent CNS malignancies at the adult recommended phase II dose. PMID:27022131

A cost-effectiveness and budget impact analysis of first-line fidaxomicin for patients with Clostridium difficile infection (CDI) in Germany.

PubMed

Watt, Maureen; McCrea, Charles; Johal, Sukhvinder; Posnett, John; Nazir, Jameel

2016-10-01

Clostridium difficile infection (CDI) represents a significant economic healthcare burden, especially the cost of recurrent disease. Fidaxomicin produced significantly lower recurrence rates and higher sustained cure rates in clinical trials. We evaluated the cost-effectiveness and budget impact of fidaxomicin compared with vancomycin in Germany in the first-line treatment of patient subgroups with CDI at increased risk of recurrence. A semi-Markov model was used to compare the cost-effectiveness and budget impact of fidaxomicin vs. vancomycin from a payer perspective in Germany. The model cycle length was 10 days. The time horizon was 1 year. Model inputs were probability of clinical cure, 30-day probability of recurrence, and 30-day attributable mortality based on evidence from two randomized controlled trials comparing fidaxomicin and vancomycin in patients with CDI. Cost-effectiveness outcomes were cost per quality-adjusted life year gained, cost per bed-day saved, and cost per recurrence avoided. Despite higher drug acquisition costs, fidaxomicin was dominant in the cancer subgroup (less costly and more effective) and cost-effective in the other subgroups, with incremental cost-effectiveness ratios vs. vancomycin ranging from €26,900 to €44,500. Hospitalization costs of the first-line treatment of CDI with fidaxomicin vs. vancomycin were lower in every patient subgroup, resulting in budget impacts ranging from -€1325 (in patients ≥65 years) to -€2438 (in cancer patients). Reductions in the cost of treating recurrence with fidaxomicin ranged from -€574.32 per patient in those receiving concomitant antibiotics to -€1500.68 per patient in renally impaired patients. In patient subgroups with CDI at increased recurrence risk, fidaxomicin was cost-effective vs. vancomycin, and less costly and more effective in patients with cancer.

Adherence of Lactobacillus crispatus to vaginal epithelial cells from women with or without a history of recurrent urinary tract infection.

PubMed

Kwok, Louisa; Stapleton, Ann E; Stamm, Walter E; Hillier, Sharon L; Wobbe, Cheryl L; Gupta, Kalpana

2006-11-01

Lactobacillus crispatus strain CTV-05 is a vaginal probiotic proposed for use in women with recurrent urinary tract infection to reduce vaginal colonization with Escherichia coli and the risk of urinary tract infection. However, the ability of this probiotic strain to adhere to the target mucosa, vaginal epithelial cells, has not been assessed in women with recurrent urinary tract infection. We measured the adherence of L. crispatus strain CTV-05 to vaginal epithelial cells collected from more than 100 premenopausal women with (cases) and without (controls) a history of recurrent urinary tract infection. We also examined the effects of relevant host factors on bacterial adherence. Bacterial adherence assays were performed by combining L. crispatus CTV-05 with exfoliated vaginal epithelial cells collected from 51 case women and 51 controls. L. crispatus CTV-05 adhered in high numbers to vaginal epithelial cells from women with recurrent urinary tract infection (mean adherence of 50.5 lactobacilli per vaginal epithelial cell) and controls (mean adherence of 39.4 lactobacilli per vaginal epithelial cell). Adherence was significantly higher using vaginal epithelial cells from women with a maternal history of urinary tract infection (p = 0.036) and a nonsecretor phenotype (p < 0.001), but was not significantly affected by recent spermicide use, oral contraceptive use, menstrual cycle phase or sexual activity. L. crispatus strain CTV-05 is highly adherent to vaginal epithelial cells collected from a large sample of premenopausal women with or without a history of recent recurrent urinary tract infection. These data strongly support further evaluation of this probiotic in clinical trials of women with recurrent urinary tract infection.

Role of Left Ventricular Diastolic Dysfunction in Predicting Atrial Fibrillation Recurrence after Successful Electrical Cardioversion

PubMed Central

Melduni, Rowlens M.; Cullen, Michael W.

2013-01-01

The role of left ventricular (LV) diastolic dysfunction in predicting atrial fibrillation (AF) recurrence after successful electrical cardioversion is largely unknown. Studies suggest that there may be a link between abnormal LV compliance and the initial development, and recurrence of AF after electrical cardioversion. Although direct-current cardioversion (DCCV) is a well-established and highly effective method to convert AF to sinus rhythm, it offers little else beyond immediate rate control because it does not address the underlying cause of AF. Preservation of sinus rhythm after successful cardioversion still remains a challenge for clinicians. Despite the use of antiarrhythmic drugs and serial cardioversions, the rate of AF recurrence remains high in the first year. Current evidence suggests that diastolic dysfunction, which is associated with atrial volume and pressure overload, may be a mechanism underlying the perpetuating cycle of AF recurrence following successful electrical cardioversion. Diastolic dysfunction is considered to be a defect in the ability of the myofibrils, which have shortened against a load in systole to eject blood into the high-pressure aorta, to rapidly or completely return to their resting length. Consequently, LV filling is impaired and the non-compliant left ventricle is unable to fill at low pressures. As a result, left atrial and pulmonary vein pressure rises, and electrical and structural remodeling of the atrial myocardium ensues, creating a vulnerable substrate for AF. In this article, we review the current evidence highlighting the association of LV diastolic dysfunction with AF recurrence after successful electrical cardioversion and provide an approach to the management of LV diastolic dysfunction to prevent AF recurrence. PMID:23525127

Modeling and Simulation of a Parametrically Resonant Micromirror With Duty-Cycled Excitation

PubMed Central

Shahid, Wajiha; Qiu, Zhen; Duan, Xiyu; Li, Haijun; Wang, Thomas D.; Oldham, Kenn R.

2014-01-01

High frequency large scanning angle electrostatically actuated microelectromechanical systems (MEMS) mirrors are used in a variety of applications involving fast optical scanning. A 1-D parametrically resonant torsional micromirror for use in biomedical imaging is analyzed here with respect to operation by duty-cycled square waves. Duty-cycled square wave excitation can have significant advantages for practical mirror regulation and/or control. The mirror’s nonlinear dynamics under such excitation is analyzed in a Hill’s equation form. This form is used to predict stability regions (the voltage-frequency relationship) of parametric resonance behavior over large scanning angles using iterative approximations for nonlinear capacitance behavior of the mirror. Numerical simulations are also performed to obtain the mirror’s frequency response over several voltages for various duty cycles. Frequency sweeps, stability results, and duty cycle trends from both analytical and simulation methods are compared with experimental results. Both analytical models and simulations show good agreement with experimental results over the range of duty cycled excitations tested. This paper discusses the implications of changing amplitude and phase with duty cycle for robust open-loop operation and future closed-loop operating strategies. PMID:25506188

PARALLEL PERTURBATION MODEL FOR CYCLE TO CYCLE VARIABILITY PPM4CCV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ameen, Muhsin Mohammed; Som, Sibendu

This code consists of a Fortran 90 implementation of the parallel perturbation model to compute cyclic variability in spark ignition (SI) engines. Cycle-to-cycle variability (CCV) is known to be detrimental to SI engine operation resulting in partial burn and knock, and result in an overall reduction in the reliability of the engine. Numerical prediction of cycle-to-cycle variability (CCV) in SI engines is extremely challenging for two key reasons: (i) high-fidelity methods such as large eddy simulation (LES) are required to accurately capture the in-cylinder turbulent flow field, and (ii) CCV is experienced over long timescales and hence the simulations needmore » to be performed for hundreds of consecutive cycles. In the new technique, the strategy is to perform multiple parallel simulations, each of which encompasses 2-3 cycles, by effectively perturbing the simulation parameters such as the initial and boundary conditions. The PPM4CCV code is a pre-processing code and can be coupled with any engine CFD code. PPM4CCV was coupled with Converge CFD code and a 10-time speedup was demonstrated over the conventional multi-cycle LES in predicting the CCV for a motored engine. Recently, the model is also being applied to fired engines including port fuel injected (PFI) and direct injection spark ignition engines and the preliminary results are very encouraging.« less

Pilot Comments for High Speed Research Cycle 3 Simulations Study (LaRC.1)

NASA Technical Reports Server (NTRS)

Bailey, Melvin L. (Editor); Jackson, E. Bruce (Technical Monitor)

2000-01-01

This is a compilation of pilot comments from the Boeing High Speed Research Aircraft, Cycle 3 Simulation Study (LaRC.1) conducted from January to March 1997 at NASA Langley Research Center. This simulation study was conducted using the Visual Motion Simulator. The comments are direct tape transcriptions and have been edited for spelling only.

Characterization and functional analysis of a slow-cycling subpopulation in colorectal cancer enriched by cell cycle inducer combined chemotherapy.

PubMed

Wu, Feng-Hua; Mu, Lei; Li, Xiao-Lan; Hu, Yi-Bing; Liu, Hui; Han, Lin-Tao; Gong, Jian-Ping

2017-10-03

The concept of cancer stem cells has been proposed in various malignancies including colorectal cancer. Recent studies show direct evidence for quiescence slow-cycling cells playing a role in cancer stem cells. There exists an urgent need to isolate and better characterize these slow-cycling cells. In this study, we developed a new model to enrich slow-cycling tumor cells using cell-cycle inducer combined with cell cycle-dependent chemotherapy in vitro and in vivo . Our results show that Short-term exposure of colorectal cancer cells to chemotherapy combined with cell-cycle inducer enriches for a cell-cycle quiescent tumor cell population. Specifically, these slow-cycling tumor cells exhibit increased chemotherapy resistance in vitro and tumorigenicity in vivo . Notably, these cells are stem-cell like and participate in metastatic dormancy. Further exploration indicates that slow-cycling colorectal cancer cells in our model are less sensitive to cytokine-induced-killer cell mediated cytotoxic killing in vivo and in vitro . Collectively, our cell cycle inducer combined chemotherapy exposure model enriches for a slow-cycling, dormant, chemo-resistant tumor cell sub-population that are resistant to cytokine induced killer cell based immunotherapy. Studying unique signaling pathways in dormant tumor cells enriched by cell cycle inducer combined chemotherapy treatment is expected to identify novel therapeutic targets for preventing tumor recurrence.

Characterization and functional analysis of a slow-cycling subpopulation in colorectal cancer enriched by cell cycle inducer combined chemotherapy

PubMed Central

Wu, Feng-Hua; Mu, Lei; Li, Xiao-Lan; Hu, Yi-Bing; Liu, Hui; Han, Lin-Tao; Gong, Jian-Ping

2017-01-01

The concept of cancer stem cells has been proposed in various malignancies including colorectal cancer. Recent studies show direct evidence for quiescence slow-cycling cells playing a role in cancer stem cells. There exists an urgent need to isolate and better characterize these slow-cycling cells. In this study, we developed a new model to enrich slow-cycling tumor cells using cell-cycle inducer combined with cell cycle-dependent chemotherapy in vitro and in vivo. Our results show that Short-term exposure of colorectal cancer cells to chemotherapy combined with cell-cycle inducer enriches for a cell-cycle quiescent tumor cell population. Specifically, these slow-cycling tumor cells exhibit increased chemotherapy resistance in vitro and tumorigenicity in vivo. Notably, these cells are stem-cell like and participate in metastatic dormancy. Further exploration indicates that slow-cycling colorectal cancer cells in our model are less sensitive to cytokine-induced-killer cell mediated cytotoxic killing in vivo and in vitro. Collectively, our cell cycle inducer combined chemotherapy exposure model enriches for a slow-cycling, dormant, chemo-resistant tumor cell sub-population that are resistant to cytokine induced killer cell based immunotherapy. Studying unique signaling pathways in dormant tumor cells enriched by cell cycle inducer combined chemotherapy treatment is expected to identify novel therapeutic targets for preventing tumor recurrence. PMID:29108242

An Attractor-Based Complexity Measurement for Boolean Recurrent Neural Networks

PubMed Central

Cabessa, Jérémie; Villa, Alessandro E. P.

2014-01-01

We provide a novel refined attractor-based complexity measurement for Boolean recurrent neural networks that represents an assessment of their computational power in terms of the significance of their attractor dynamics. This complexity measurement is achieved by first proving a computational equivalence between Boolean recurrent neural networks and some specific class of -automata, and then translating the most refined classification of -automata to the Boolean neural network context. As a result, a hierarchical classification of Boolean neural networks based on their attractive dynamics is obtained, thus providing a novel refined attractor-based complexity measurement for Boolean recurrent neural networks. These results provide new theoretical insights to the computational and dynamical capabilities of neural networks according to their attractive potentialities. An application of our findings is illustrated by the analysis of the dynamics of a simplified model of the basal ganglia-thalamocortical network simulated by a Boolean recurrent neural network. This example shows the significance of measuring network complexity, and how our results bear new founding elements for the understanding of the complexity of real brain circuits. PMID:24727866

The partly Aalen's model for recurrent event data with a dependent terminal event.

PubMed

Chen, Chyong-Mei; Shen, Pao-Sheng; Chuang, Ya-Wen

2016-01-30

Recurrent event data are commonly observed in biomedical longitudinal studies. In many instances, there exists a terminal event, which precludes the occurrence of additional repeated events, and usually there is also a nonignorable correlation between the terminal event and recurrent events. In this article, we propose a partly Aalen's additive model with a multiplicative frailty for the rate function of recurrent event process and assume a Cox frailty model for terminal event time. A shared gamma frailty is used to describe the correlation between the two types of events. Consequently, this joint model can provide the information of temporal influence of absolute covariate effects on the rate of recurrent event process, which is usually helpful in the decision-making process for physicians. An estimating equation approach is developed to estimate marginal and association parameters in the joint model. The consistency of the proposed estimator is established. Simulation studies demonstrate that the proposed approach is appropriate for practical use. We apply the proposed method to a peritonitis cohort data set for illustration. Copyright © 2015 John Wiley & Sons, Ltd.

Recurrence Methods for the Identification of Morphogenetic Patterns

PubMed Central

Facchini, Angelo; Mocenni, Chiara

2013-01-01

This paper addresses the problem of identifying the parameters involved in the formation of spatial patterns in nonlinear two dimensional systems. To this aim, we perform numerical experiments on a prototypical model generating morphogenetic Turing patterns, by changing both the spatial frequency and shape of the patterns. The features of the patterns and their relationship with the model parameters are characterized by means of the Generalized Recurrence Quantification measures. We show that the recurrence measures Determinism and Recurrence Entropy, as well as the distribution of the line lengths, allow for a full characterization of the patterns in terms of power law decay with respect to the parameters involved in the determination of their spatial frequency and shape. A comparison with the standard two dimensional Fourier transform is performed and the results show a better performance of the recurrence indicators in identifying a reliable connection with the spatial frequency of the patterns. Finally, in order to evaluate the robustness of the estimation of the power low decay, extensive simulations have been performed by adding different levels of noise to the patterns. PMID:24066062

Synchronization Of Parallel Discrete Event Simulations

NASA Technical Reports Server (NTRS)

Steinman, Jeffrey S.

1992-01-01

Adaptive, parallel, discrete-event-simulation-synchronization algorithm, Breathing Time Buckets, developed in Synchronous Parallel Environment for Emulation and Discrete Event Simulation (SPEEDES) operating system. Algorithm allows parallel simulations to process events optimistically in fluctuating time cycles that naturally adapt while simulation in progress. Combines best of optimistic and conservative synchronization strategies while avoiding major disadvantages. Algorithm processes events optimistically in time cycles adapting while simulation in progress. Well suited for modeling communication networks, for large-scale war games, for simulated flights of aircraft, for simulations of computer equipment, for mathematical modeling, for interactive engineering simulations, and for depictions of flows of information.

Statistical modelling for recurrent events: an application to sports injuries

PubMed Central

Ullah, Shahid; Gabbett, Tim J; Finch, Caroline F

2014-01-01

Background Injuries are often recurrent, with subsequent injuries influenced by previous occurrences and hence correlation between events needs to be taken into account when analysing such data. Objective This paper compares five different survival models (Cox proportional hazards (CoxPH) model and the following generalisations to recurrent event data: Andersen-Gill (A-G), frailty, Wei-Lin-Weissfeld total time (WLW-TT) marginal, Prentice-Williams-Peterson gap time (PWP-GT) conditional models) for the analysis of recurrent injury data. Methods Empirical evaluation and comparison of different models were performed using model selection criteria and goodness-of-fit statistics. Simulation studies assessed the size and power of each model fit. Results The modelling approach is demonstrated through direct application to Australian National Rugby League recurrent injury data collected over the 2008 playing season. Of the 35 players analysed, 14 (40%) players had more than 1 injury and 47 contact injuries were sustained over 29 matches. The CoxPH model provided the poorest fit to the recurrent sports injury data. The fit was improved with the A-G and frailty models, compared to WLW-TT and PWP-GT models. Conclusions Despite little difference in model fit between the A-G and frailty models, in the interest of fewer statistical assumptions it is recommended that, where relevant, future studies involving modelling of recurrent sports injury data use the frailty model in preference to the CoxPH model or its other generalisations. The paper provides a rationale for future statistical modelling approaches for recurrent sports injury. PMID:22872683

Local and global approaches to the problem of Poincaré recurrences. Applications in nonlinear dynamics

NASA Astrophysics Data System (ADS)

Anishchenko, V. S.; Boev, Ya. I.; Semenova, N. I.; Strelkova, G. I.

2015-07-01

We review rigorous and numerical results on the statistics of Poincaré recurrences which are related to the modern development of the Poincaré recurrence problem. We analyze and describe the rigorous results which are achieved both in the classical (local) approach and in the recently developed global approach. These results are illustrated by numerical simulation data for simple chaotic and ergodic systems. It is shown that the basic theoretical laws can be applied to noisy systems if the probability measure is ergodic and stationary. Poincaré recurrences are studied numerically in nonautonomous systems. Statistical characteristics of recurrences are analyzed in the framework of the global approach for the cases of positive and zero topological entropy. We show that for the positive entropy, there is a relationship between the Afraimovich-Pesin dimension, Lyapunov exponents and the Kolmogorov-Sinai entropy either without and in the presence of external noise. The case of zero topological entropy is exemplified by numerical results for the Poincare recurrence statistics in the circle map. We show and prove that the dependence of minimal recurrence times on the return region size demonstrates universal properties for the golden and the silver ratio. The behavior of Poincaré recurrences is analyzed at the critical point of Feigenbaum attractor birth. We explore Poincaré recurrences for an ergodic set which is generated in the stroboscopic section of a nonautonomous oscillator and is similar to a circle shift. Based on the obtained results we show how the Poincaré recurrence statistics can be applied for solving a number of nonlinear dynamics issues. We propose and illustrate alternative methods for diagnosing effects of external and mutual synchronization of chaotic systems in the context of the local and global approaches. The properties of the recurrence time probability density can be used to detect the stochastic resonance phenomenon. We also discuss how the fractal dimension of chaotic attractors can be estimated using the Poincaré recurrence statistics.

Sensitivity of Global Terrestrial Gross Primary Production to Hydrologic States Simulated by the Community Land Model Using Two Runoff Parameterizations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lei, Huimin; Huang, Maoyi; Leung, Lai-Yung R.

2014-09-01

The terrestrial water and carbon cycles interact strongly at various spatio-temporal scales. To elucidate how hydrologic processes may influence carbon cycle processes, differences in terrestrial carbon cycle simulations induced by structural differences in two runoff generation schemes were investigated using the Community Land Model 4 (CLM4). Simulations were performed with runoff generation using the default TOPMODEL-based and the Variable Infiltration Capacity (VIC) model approaches under the same experimental protocol. The comparisons showed that differences in the simulated gross primary production (GPP) are mainly attributed to differences in the simulated leaf area index (LAI) rather than soil moisture availability. More specifically,more » differences in runoff simulations can influence LAI through changes in soil moisture, soil temperature, and their seasonality that affect the onset of the growing season and the subsequent dynamic feedbacks between terrestrial water, energy, and carbon cycles. As a result of a relative difference of 36% in global mean total runoff between the two models and subsequent changes in soil moisture, soil temperature, and LAI, the simulated global mean GPP differs by 20.4%. However, the relative difference in the global mean net ecosystem exchange between the two models is small (2.1%) due to competing effects on total mean ecosystem respiration and other fluxes, although large regional differences can still be found. Our study highlights the significant interactions among the water, energy, and carbon cycles and the need for reducing uncertainty in the hydrologic parameterization of land surface models to better constrain carbon cycle modeling.« less

Effects of the scatter in sunspot group tilt angles on the large-scale magnetic field at the solar surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, J.; Cameron, R. H.; Schüssler, M., E-mail: jiejiang@nao.cas.cn

The tilt angles of sunspot groups represent the poloidal field source in Babcock-Leighton-type models of the solar dynamo and are crucial for the build-up and reversals of the polar fields in surface flux transport (SFT) simulations. The evolution of the polar field is a consequence of Hale's polarity rules, together with the tilt angle distribution which has a systematic component (Joy's law) and a random component (tilt-angle scatter). We determine the scatter using the observed tilt angle data and study the effects of this scatter on the evolution of the solar surface field using SFT simulations with flux input basedmore » upon the recorded sunspot groups. The tilt angle scatter is described in our simulations by a random component according to the observed distributions for different ranges of sunspot group size (total umbral area). By performing simulations with a number of different realizations of the scatter we study the effect of the tilt angle scatter on the global magnetic field, especially on the evolution of the axial dipole moment. The average axial dipole moment at the end of cycle 17 (a medium-amplitude cycle) from our simulations was 2.73 G. The tilt angle scatter leads to an uncertainty of 0.78 G (standard deviation). We also considered cycle 14 (a weak cycle) and cycle 19 (a strong cycle) and show that the standard deviation of the axial dipole moment is similar for all three cycles. The uncertainty mainly results from the big sunspot groups which emerge near the equator. In the framework of Babcock-Leighton dynamo models, the tilt angle scatter therefore constitutes a significant random factor in the cycle-to-cycle amplitude variability, which strongly limits the predictability of solar activity.« less

Endometrial injury to overcome recurrent embryo implantation failure: a systematic review and meta-analysis.

PubMed

Potdar, Neelam; Gelbaya, Tarek; Nardo, Luciano G

2012-12-01

Mechanical endometrial injury (biopsy/scratch or hysteroscopy) in the cycle preceding ovarian stimulation for IVF has been proposed to improve implantation in women with unexplained recurrent implantation failure (RIF). This is a systematic review and meta-analysis of studies comparing the efficacy of endometrial injury versus no intervention in women with RIF undergoing IVF. All controlled studies of endometrial biopsy/scratch or hysteroscopy performed in the cycle preceding ovarian stimulation were included and the primary outcome measure was clinical pregnancy rate. Pooling of seven controlled studies (four randomized and three non-randomized), with 2062 participants, showed that local endometrial injury induced in the cycle preceding ovarian stimulation is 70% more likely to result in a clinical pregnancy as opposed to no intervention. There was no statistically significant heterogeneity in the methods used, clinical pregnancy rates being twice as high with biopsy/scratch (RR 2.32, 95% CI 1.72-3.13) as opposed to hysteroscopy (RR 1.51, 95% CI 1.30-1.75). The evidence is strongly in favour of inducing local endometrial injury in the preceding cycle of ovarian stimulation to improve pregnancy outcomes in women with unexplained RIF. However, large randomized studies are required before iatrogenic induction of local endometrial injury can be warranted in routine clinical practice. Some women undergoing IVF treatment fail to conceive despite several attempts with good-quality embryos and no identifiable reason. We call this 'recurrent implantation failure' (RIF) where the embryo fails to embed or implant within the lining of the womb. Studies have shown that inducing injury to the lining of the womb in the cycle before starting ovarian stimulation for IVF can help improve the chances of achieving pregnancy. Injury can be induced by either scratching the lining of the womb using a biopsy tube or by telescopic investigation of the womb using a camera. We performed a collective review of the available good-quality studies that used the above two methods in the cycle prior to starting ovarian stimulation for IVF. We pooled results from seven studies, which included 2062 women with RIF and assessed the difference in clinical pregnancy rates for those undergoing injury to the womb lining compared with no injury prior to IVF. The results suggest that inducing injury is 70% more likely to result in a clinical pregnancy as opposed to no treatment. Furthermore, scratching of the lining was 2-times more likely to result in a clinical pregnancy compared with telescopic evaluation of the lining of the womb. This study suggests that in women with RIF, inducing local injury to the womb lining in the cycle prior to starting ovarian stimulation for IVF can improve pregnancy outcomes. However, large studies are required before this can be warranted in routine clinical practice. Copyright © 2012 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Fibre multi-wave mixing combs reveal the broken symmetry of Fermi-Pasta-Ulam recurrence

NASA Astrophysics Data System (ADS)

Mussot, Arnaud; Naveau, Corentin; Conforti, Matteo; Kudlinski, Alexandre; Copie, Francois; Szriftgiser, Pascal; Trillo, Stefano

2018-05-01

In optical fibres, weak modulations can grow at the expense of a strong pump to form a triangular comb of sideband pairs, until the process is reversed. Repeated cycles of such conversion and back-conversion constitute a manifestation of the universal nonlinear phenomenon known as Fermi-Pasta-Ulam recurrence. However, it remains a major challenge to observe the coexistence of different types of recurrences owing to the spontaneous symmetry-breaking nature of such a phenomenon. Here, we implement a novel non-destructive technique that allows the evolution in amplitude and phase of frequency modes to be reconstructed via post-processing of the fibre backscattered light. We clearly observe how control of the input modulation seed results in different recursive behaviours emerging from the phase-space structure dictated by the spontaneously broken symmetry. The proposed technique is an important tool to characterize other mixing processes and new regimes of rogue-wave formation and wave turbulence in fibre optics.

[A Case of Resected Gastric Cancer Invading the Esophagus with Esophageal Recurrence That Responded to Weekly Docetaxel／Cisplatin Chemotherapy].

PubMed

Maezawa, Yukio; Hayashi, Tsutomu; Yamamoto, Jun; Ohnishi, Hiroshi; Horii, Nobutoshi; Inoue, Hirohide; Kimura, Jun; Takagawa, Ryo; Makino, Hirochika; Suzuki, Yoshihiro; Ohshima, Takashi; Tsuburaya, Akira; Rino, Yasushi; Kunisaki, Chikara; Masuda, Munetaka

2015-10-01

A 77-year-old man underwent total gastrectomy with D1+ lymph node dissection after being diagnosed with cT4aN2M0, cStage ⅢB gastric cancer. Peritoneal dissemination was detected in the bursa omentalis. The pathological diagnosis after surgery was pT4aN3b (21/41) M1 (P1). He was treated with 6 courses of S-1 chemotherapy. Two years after surgery, upper gastrointestinal endoscopy revealed the presence of a tumor in the mid-thoracic esophagus. It was diagnosed to as metastatic esophageal cancer and treated with combination chemotherapy consisting of docetaxel (25 mg/m2, days 1, 8, 15) and cisplatin (25 mg/m2, days 1, 8, 15) in a 28-day cycle. A clinically complete response was observed after 5 courses of chemotherapy. Currently, the patient is alive with no signs of recurrence 12 months after the initial recurrence.

[Nasopharyngeal adenoid cystic carcinoma, a rare but highly challenging disease with unmet therapeutic needs: A case-report and review of the literature].

PubMed

Afani, L; Errihani, H; Benchafai, I; Lalami, Y

2016-07-01

Nasopharyngeal adenoid cystic carcinoma is a rare tumour. Compared with others nasopharyngeal tumours, it is characterised by slow evolution but it is locally aggressive and has a high tendency to recurrences. Due to the rarity of cases, no consensus exists about treatment approaches. We report the case of 45-year-old-man with a locally advanced adenoid cystic carcinoma. The patient received concurrent chemoradiation and had a good objective response. After one year, he developed a paucisymptomatic lung metastasis. The follow-up showed local recurrence after 3 years. One cycle of chemotherapy was given but poorly supported. Carbon ion radiotherapy was proposed. The aim of this work is to review the literature concerning this rare malignancy and discusses treatment approaches in initial situations and during recurrences. Copyright © 2016 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

From blackbirds to black holes: Investigating capture-recapture methods for time domain astronomy

NASA Astrophysics Data System (ADS)

Laycock, Silas G. T.

2017-07-01

In time domain astronomy, recurrent transients present a special problem: how to infer total populations from limited observations. Monitoring observations may give a biassed view of the underlying population due to limitations on observing time, visibility and instrumental sensitivity. A similar problem exists in the life sciences, where animal populations (such as migratory birds) or disease prevalence, must be estimated from sparse and incomplete data. The class of methods termed Capture-Recapture is used to reconstruct population estimates from time-series records of encounters with the study population. This paper investigates the performance of Capture-Recapture methods in astronomy via a series of numerical simulations. The Blackbirds code simulates monitoring of populations of transients, in this case accreting binary stars (neutron star or black hole accreting from a stellar companion) under a range of observing strategies. We first generate realistic light-curves for populations of binaries with contrasting orbital period distributions. These models are then randomly sampled at observing cadences typical of existing and planned monitoring surveys. The classical capture-recapture methods, Lincoln-Peterson, Schnabel estimators, related techniques, and newer methods implemented in the Rcapture package are compared. A general exponential model based on the radioactive decay law is introduced which is demonstrated to recover (at 95% confidence) the underlying population abundance and duty cycle, in a fraction of the observing visits (10-50%) required to discover all the sources in the simulation. Capture-Recapture is a promising addition to the toolbox of time domain astronomy, and methods implemented in R by the biostats community can be readily called from within python.

Quantifying Precipitation Variability and Relative Erosion Rates on Titan Using a GCM and Implications for Observed Geomorphology

NASA Astrophysics Data System (ADS)

Faulk, S.; Moon, S.; Mitchell, J.; Lora, J. M.

2016-12-01

Titan's zonal-mean precipitation behavior has been widely investigated using general circulation models (GCMs), but the spatial and temporal variability of rainfall in Titan's active hydrologic cycle is less well understood. We conduct statistical analyses of rainfall, diagnosed from GCM simulations of Titan's atmosphere, to determine storm intensity and frequency. Intense storms of methane have been proposed to be critical for enabling mechanical erosion of Titan's surface, as indicated by extensive observations of dendritic valley networks. Using precipitation outputs from the Titan Atmospheric Model (TAM), a GCM shown to realistically simulate many features of Titan's atmosphere, we quantify the precipitation variability and resulting relative erosion rates within eight separate latitude bins for a variety of initial surface liquid distributions. We find that while the overall wettest regions are indeed the poles, the most intense rainfall generally occurs in the high mid-latitudes, between 45-67.5 degrees, consistent with recent geomorphological observations of alluvial fans concentrated at those latitudes. We also find that precipitation rates necessary for surface erosion, as estimated by Perron et al. (2006) J. Geophys. Res. 111, E11001, frequently occur at all latitudes, with recurrence intervals of less than one Titan year. Such analysis is crucial towards understanding the complex interaction between Titan's atmosphere and surface and defining the influence of precipitation on observed geomorphology.

Treatment of breast cancer in a patient of Alport syndrome-induced chronic renal failure: A triumph story.

PubMed

Modi, Gaurang; Madabhavi, Irappa; Patel, Apurva; Anand, Asha

2018-01-01

Alport syndrome is a hereditary disease of the glomerular basement membrane, characterized by the familial occurrence of progressive, hematuric nephropathy with sensorineural deafness. We are reporting here a young adult female, suffering from Alport syndrome with significant family history and on maintenance twice-weekly hemodialysis (HD), had been diagnosed with triple negative earlystage right-sided breast cancer. The patient was managed successfully with surgery and adjuvant chemotherapy with 3 cycles of 5-flurouracil, doxorubicin, and cyclophosphamide and 3 cycles of docetaxel. In this case, our clinical challenge was dose reduction of chemotherapeutic agents according to creatinine clearance and timing of HD in each cycle of chemotherapy. We confronted this by dose reduction of cyclophosphamide and timing of chemotherapy was at least 12 h after HD for each and every cycle. Patient is in regular follow-up in our department since 20 months without any recurrence of the disease.

A Phenomenological Study of the Factors Leading Low Socioeconomic Status Urban Students to Enroll in a University

ERIC Educational Resources Information Center

Schultheis, Luke D.

2013-01-01

Low socioeconomic urban students do not attend universities at a rate proportional to other populations. This perpetuates a cycle of recurrence and diminished potential benefits associated with degree attainment. The commonly ascribed Theory of Student Choice (Hossler, Braxton & Coopersmith, 1989) does not apply to this population. The purpose…

On the Origin of Genres by Natural Selection: Inventing Genres Online.

ERIC Educational Resources Information Center

Hunt, Russell A.

The study of discourse genres as social action has steadily displaced more traditional views of genre, proposing the organic and ecological model that any consistent pattern of response to a recurrent rhetorical situation might constitute a genre. Observation of the life cycles of genres as transient social events can occur in a classroom using…

About a mathematical model of market

NASA Astrophysics Data System (ADS)

Kulikov, D. A.

2017-01-01

In the paper a famous mathematical model of macroeconomics, which is called “market model” was considered. Traditional versions of this model have no periodic solutions and, therefore, they cannot describe a cyclic recurrence of the market economy. In the paper for the corresponding equation a delay was added. It allows obtaining sufficient conditions for existence of the stable cycles.

Effects of One Cycle of Recurrent Selection for Early Blight Resistance in a Diploid Hybrid Solanum phureja-S. stenotomum Population

USDA-ARS?s Scientific Manuscript database

Early blight, caused by Alternaria solani, is the second most important foliar disease in potatoes, after late blight, around the world. Heritable early blight resistance was previously identified in a diploid hybrid population of Solanum phureja-S. stenotomum (phu-stn). Seventy-two clones, consis...

A Brownian model for recurrent earthquakes

USGS Publications Warehouse

Matthews, M.V.; Ellsworth, W.L.; Reasenberg, P.A.

2002-01-01

We construct a probability model for rupture times on a recurrent earthquake source. Adding Brownian perturbations to steady tectonic loading produces a stochastic load-state process. Rupture is assumed to occur when this process reaches a critical-failure threshold. An earthquake relaxes the load state to a characteristic ground level and begins a new failure cycle. The load-state process is a Brownian relaxation oscillator. Intervals between events have a Brownian passage-time distribution that may serve as a temporal model for time-dependent, long-term seismic forecasting. This distribution has the following noteworthy properties: (1) the probability of immediate rerupture is zero; (2) the hazard rate increases steadily from zero at t = 0 to a finite maximum near the mean recurrence time and then decreases asymptotically to a quasi-stationary level, in which the conditional probability of an event becomes time independent; and (3) the quasi-stationary failure rate is greater than, equal to, or less than the mean failure rate because the coefficient of variation is less than, equal to, or greater than 1/???2 ??? 0.707. In addition, the model provides expressions for the hazard rate and probability of rupture on faults for which only a bound can be placed on the time of the last rupture. The Brownian relaxation oscillator provides a connection between observable event times and a formal state variable that reflects the macromechanics of stress and strain accumulation. Analysis of this process reveals that the quasi-stationary distance to failure has a gamma distribution, and residual life has a related exponential distribution. It also enables calculation of "interaction" effects due to external perturbations to the state, such as stress-transfer effects from earthquakes outside the target source. The influence of interaction effects on recurrence times is transient and strongly dependent on when in the loading cycle step pertubations occur. Transient effects may be much stronger than would be predicted by the "clock change" method and characteristically decay inversely with elapsed time after the perturbation.

Preference of elderly patients' to oral or intravenous chemotherapy in heavily pre-treated recurrent ovarian cancer: final results of a prospective multicenter trial.

PubMed

Chekerov, Radoslav; Harter, Philipp; Fuxius, Stefan; Hanker, Lars Christian; Woelber, Linn; Müller, Lothar; Klare, Peter; Abenhardt, Wolfgang; Nedkova, Yoana; Yalcinkaya, Isil; Heinrich, Georg; Sommer, Harald; Mahner, Sven; Wimberger, Pauline; Koensgen-Mustea, Dominique; Richter, Rolf; Oskay-Oezcelik, Gülten; Sehouli, Jalid

2017-01-01

Palliative systemic treatment in elderly gynaecological cancer patients remains a major challenge. In recurrent ovarian cancer (ROC), treosulfan an active alkylating drug showed similar cytotoxicity whether as oral (p.o.) or intravenous (i.v.) application. The aim of this innovative trial was to evaluate the preference of elderly patients (≥65 years) for p.o. or i.v. chemotherapy focusing compliance, outcome, toxicities, and geriatric aspects as secondary endpoints. Patients with ROC had the free choice between treosulfan i.v. (7000 mg/m 2 d1, q29d) or p.o. (600 mg/m 2 daily d1-28, q57d). Only indecisive participants were randomized. Overall 123 patients with 2 nd to 5 th recurrence were registered and 119 received at least one cycle of chemotherapy. 85.7% preferred treosulfan i.v. and 14.3% oral, where only three patients were randomized. Main reasons for i.v. preference associated with individual expectations of lower rate of gastrointestinal disorders, higher activity and tolerability of treatment. Median of applied chemotherapies was three (range 1-12 cycles), with most common grade 3/4 toxicities thrombopenia (18.7%), leukopenia (15.7%), ascites (7.6%), bowel obstruction (6.7%), and abdominal pain (4.2%). Median time until progression/overall survival was 5.2/7.8 months (i.v.), and 5.6/10.4 months (p.o.), respectively, without significant differences in efficacy. Elderly patients with recurrent ovarian cancer asked and demonstrated active participation in the decision-making process of their oncological treatment and favoured predominantly the i.v. application. Treosulfan was generally well-tolerated despite comorbidities and heavy pre-treatment. Our study demonstrates that patients' preference did not influence prognosis negatively and remains important in gynaecologic oncology decision practice. 2004-000719-25; NCT 00170690.

Substorm occurrence rates, substorm recurrence times, and solar wind structure

NASA Astrophysics Data System (ADS)

Borovsky, Joseph E.; Yakymenko, Kateryna

2017-03-01

Two collections of substorms are created: 28,464 substorms identified with jumps in the SuperMAG AL index in the years 1979-2015 and 16,025 substorms identified with electron injections into geosynchronous orbit in the years 1989-2007. Substorm occurrence rates and substorm recurrence-time distributions are examined as functions of the phase of the solar cycle, the season of the year, the Russell-McPherron favorability, the type of solar wind plasma at Earth, the geomagnetic-activity level, and as functions of various solar and solar wind properties. Three populations of substorm occurrences are seen: (1) quasiperiodically occurring substorms with recurrence times (waiting times) of 2-4 h, (2) randomly occurring substorms with recurrence times of about 6-15 h, and (3) long intervals wherein no substorms occur. A working model is suggested wherein (1) the period of periodic substorms is set by the magnetosphere with variations in the actual recurrence times caused by the need for a solar wind driving interval to occur, (2) the mesoscale structure of the solar wind magnetic field triggers the occurrence of the random substorms, and (3) the large-scale structure of the solar wind plasma is responsible for the long intervals wherein no substorms occur. Statistically, the recurrence period of periodically occurring substorms is slightly shorter when the ram pressure of the solar wind is high, when the magnetic field strength of the solar wind is strong, when the Mach number of the solar wind is low, and when the polar-cap potential saturation parameter is high.

Low-Dose Nocturnal Tegaserod or Erythromycin Delays Symptom Recurrence After Treatment of Irritable Bowel Syndrome Based on Presumed Bacterial Overgrowth

PubMed Central

Morales, Walter; Lezcano, Sheila; Sun-Chuan, Dai; Low, Kimberly; Yang, Janet

2009-01-01

Our group previously demonstrated a deficiency of migrating motor complexes in irritable bowel syndrome (IBS) patients with small intestinal bacterial overgrowth (SIBO). Based on disturbed fasting motility, we tested whether low-dose nocturnal erythromycin or tegaserod can prevent the recurrence of IBS symptoms after successful antibiotic treatment. Methods: 203 patient charts were reviewed to find IBS patients with SIBO, and treatment cycles were assessed to identify subjects with clinical and breath test resolution. The charts of those who met the inclusion criteria were reviewed to determine the method of prevention of symptom recurrence and the length of remission. The two preventive agents used were erythromycin (50 mg) or tegaserod (2–6 mg) orally at bedtime. Results: 64 patients met the inclusion criteria. Subjects receiving no prevention (n=6) after successful antibiotic treatment experienced symptom recurrence after 59.7±47.4 days. Prevention using erythromycin (n=42) demonstrated 138.5±132.2 symptom-free days (P=.08 vs no prevention) compared to 241.6±162.2 days with tegaserod (n=16; P=.003 vs no prevention; P=.004 vs erythromycin). Switching from erythromycin to tegaserod (n=20) extended resolution from 105.8±73.3 days to 199.7±162.9 days (P=.04). Changing from no therapy to erythromycin or tegaserod (n=6) extended recurrence from 41.0±44.8 days to 195.6±153.5 days (P=.06). Conclusion: Tegaserod significantly prevents the recurrence of IBS symptoms after antibiotic treatment compared to erythromycin or no prevention. PMID:20574504

Knowledge Based Simulation: An Artificial Intelligence Approach to System Modeling and Automating the Simulation Life Cycle.

DTIC Science & Technology

1988-04-13

Simulation: An Artificial Intelligence Approach to System Modeling and Automating the Simulation Life Cycle Mark S. Fox, Nizwer Husain, Malcolm...McRoberts and Y.V.Reddy CMU-RI-TR-88-5 Intelligent Systems Laboratory The Robotics Institute Carnegie Mellon University Pittsburgh, Pennsylvania D T T 13...years of research in the application of Artificial Intelligence to Simulation. Our focus has been in two areas: the use of Al knowledge representation

Simulated precipitation diurnal cycles over East Asia using different CAPE-based convective closure schemes in WRF model

NASA Astrophysics Data System (ADS)

Yang, Ben; Zhou, Yang; Zhang, Yaocun; Huang, Anning; Qian, Yun; Zhang, Lujun

2018-03-01

Closure assumption in convection parameterization is critical for reasonably modeling the precipitation diurnal variation in climate models. This study evaluates the precipitation diurnal cycles over East Asia during the summer of 2008 simulated with three convective available potential energy (CAPE) based closure assumptions, i.e. CAPE-relaxing (CR), quasi-equilibrium (QE), and free-troposphere QE (FTQE) and investigates the impacts of planetary boundary layer (PBL) mixing, advection, and radiation on the simulation by using the weather research and forecasting model. The sensitivity of precipitation diurnal cycle to PBL vertical resolution is also examined. Results show that the precipitation diurnal cycles simulated with different closures all exhibit large biases over land and the simulation with FTQE closure agrees best with observation. In the simulation with QE closure, the intensified PBL mixing after sunrise is responsible for the late-morning peak of convective precipitation, while in the simulation with FTQE closure, convective precipitation is mainly controlled by advection cooling. The relative contributions of different processes to precipitation formation are functions of rainfall intensity. In the simulation with CR closure, the dynamical equilibrium in the free troposphere still can be reached, implying the complex cause-effect relationship between atmospheric motion and convection. For simulations in which total CAPE is consumed for the closures, daytime precipitation decreases with increased PBL resolution because thinner model layer produces lower convection starting layer, leading to stronger downdraft cooling and CAPE consumption. The sensitivity of the diurnal peak time of precipitation to closure assumption can also be modulated by changes in PBL vertical resolution. The results of this study help us better understand the impacts of various processes on the precipitation diurnal cycle simulation.

Using Dynamic Simulation to Evaluate Attemperator Operation in a Natural Gas Combined Cycle With Duct Burners in the Heat Recovery Steam Generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liese, Eric; Zitney, Stephen E.

A generic training simulator of a natural gas combined cycle was modified to match operations at a real plant. The objective was to use the simulator to analyze cycling operations of the plant. Initial operation of the simulator revealed the potential for saturation conditions in the final high pressure superheater as the attemperator tried to control temperature at the superheater outlet during gas turbine loading and unloading. Subsequent plant operational data confirmed simulation results. Multiple simulations were performed during loading and unloading of the gas turbine to determine operational strategies that prevented saturation and increased the approach to saturation temperature.more » The solutions included changes to the attemperator temperature control setpoints and strategic control of the steam turbine inlet pressure control valve.« less

Anticipation of the landing shock phenomenon in flight simulation

NASA Technical Reports Server (NTRS)

Mcfarland, Richard E.

1987-01-01

An aircraft landing may be described as a controlled crash because a runway surface is intercepted. In a simulation model the transition from aerodynamic flight to weight on wheels involves a single computational cycle during which stiff differential equations are activated; with a significant probability these initial conditions are unrealistic. This occurs because of the finite cycle time, during which large restorative forces will accompany unrealistic initial oleo compressions. This problem was recognized a few years ago at Ames Research Center during simulation studies of a supersonic transport. The mathematical model of this vehicle severely taxed computational resources, and required a large cycle time. The ground strike problem was solved by a described technique called anticipation equations. This extensively used technique has not been previously reported. The technique of anticipating a significant event is a useful tool in the general field of discrete flight simulation. For the differential equations representing a landing gear model stiffness, rate of interception and cycle time may combine to produce an unrealistic simulation of the continuum.

[Effects of fire recurrence on fire behaviour in cork oak woodlands (Quercus suber L.) and Mediterranean shrublands over the last fifty years].

PubMed

Schaffhauser, Alice; Pimont, François; Curt, Thomas; Cassagne, Nathalie; Dupuy, Jean-Luc; Tatoni, Thierry

2015-12-01

Past fire recurrence impacts the vegetation structure, and it is consequently hypothesized to alter its future fire behaviour. We examined the fire behaviour in shrubland-forest mosaics of southeastern France, which were organized along a range of fire frequency (0 to 3-4 fires along the past 50 years) and had different time intervals between fires. The mosaic was dominated by Quercus suber L. and Erica-Cistus shrubland communities. We described the vegetation structure through measurements of tree height, base of tree crown or shrub layer, mean diameter, cover, plant water content and bulk density. We used the physical model Firetec to simulate the fire behaviour. Fire intensity, fire spread, plant water content and biomass loss varied significantly according to fire recurrence and vegetation structure, mainly linked to the time since the last fire, then the number of fires. These results confirm that past fire recurrence affects future fire behaviour, with multi-layered vegetation (particularly high shrublands) producing more intense fires, contrary to submature Quercus woodlands that have not burnt since 1959 and that are unlikely to reburn. Further simulations, with more vegetation scenes according to shrub and canopy covers, will complete this study in order to discuss the fire propagation risk in heterogeneous vegetation, particularly in the Mediterranean area, with a view to a local management of these ecosystems. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Circum-Pacific seismic potential: 1989-1999

USGS Publications Warehouse

Nishenko, S.P.

1991-01-01

The seismic potential for 96 segments of simple plate boundaries around the circum-Pacific region is presented in terms of the conditional probability for the occurrence of either large or great interplate earthquakes during the next 5, 10, and 20 years (i.e., 1989-1994, 1989-1999 and 1989-2009). This study represents the first probabilistic summary of seismic potential on this scale, and involves the comparison of plate boundary segments that exhibit varying recurrence times, magnitudes, and tectonic regimes. Presenting these data in a probabilistic framework provides a basis for the uniform comparison of seismic hazard between these differing fault segments, as well as accounting for individual variations in recurrence time along a specific fault segment, and uncertainties in the determination of the average recurrence time. The definition of specific segments along simple plate boundaries relies on the mapping of earthquake rupture zones as defined by the aftershock distributions of prior large and great earthquakes, and historic descriptions of felt intensities and damage areas. The 96 segments are chosen to represent areas likely to be ruptured by "characteristic" earthquakes of a specified size or magnitude. The term characteristic implies repeated breakage of a plate boundary segment by large or great earthquakes whose source dimensions are similar from cycle to cycle. This definition does not exclude the possibility that occasionally adjacent characteristic earthquake segments may break together in a single, larger event. Conversely, a segment may also break in a series of smaller ruptures. Estimates of recurrence times and conditional probabilities for characteristic earthquakes along segments of simple plate boundaries are based on 1) the historic and instrumental record of large and great earthquake occurrence; 2) paleoseismic evidence of recurrence from radiometric dating of Holocene features produced by earthquakes; 3) direct calculations of recurrence time from the size of the most recent characteristic event and the long-term rates of plate motion assuming the validity of the time-predictable model for earthquake recurrence; and 4) the application of a lognormal distribution for the recurrence times of large and great earthquakes. Time-dependent estimates of seismic potential are based on a physical model of earthquake occurrence which assumes that the probability for an earthquake is low immediately following the occurrence of a characteristic earthquake and increases with time as the stress on the fault segment recovers the stress drop of the event. This study updates earlier work on seismic gaps by explicitly including both recurrence time information and the temporal proximity to the next event as factors in describing earthquake hazards. Currently, 11 out of 96 regions have a high (i.e., ???50%) probability of recurrence during the next 10 years and are characterized by either fairly short (i.e., less than 30-40 years) recurrence times or long elapsed times relative to the average recurrence time. The majority of these segments are located in the southwest Pacific (Vanuatu, New Guinea, and Tonga). When a longer time window is considered (e.g., 20 years or 1989-2009), 30 out of 96 regions have a high potential. Many of these regions are located near areas of high population density. These determinations do not preclude rupture of other fault segments, with less than a 50% chance in 10 or 20 years, or large and great earthquakes in areas we have not studied in detail. While this study has summarized the seismic potential for a large number of regions around the circum-Pacific, there are still a number of geographic and seismotectonic regions that need to be considered, including Indonesia, the Philippines, New Zealand, and the countries that surround the Caribbean basin. ?? 1991 Birkha??user Verlag.

Learning State Space Dynamics in Recurrent Networks

NASA Astrophysics Data System (ADS)

Simard, Patrice Yvon

Fully recurrent (asymmetrical) networks can be used to learn temporal trajectories. The network is unfolded in time, and backpropagation is used to train the weights. The presence of recurrent connections creates internal states in the system which vary as a function of time. The resulting dynamics can provide interesting additional computing power but learning is made more difficult by the existence of internal memories. This study first exhibits the properties of recurrent networks in terms of convergence when the internal states of the system are unknown. A new energy functional is provided to change the weights of the units in order to the control the stability of the fixed points of the network's dynamics. The power of the resultant algorithm is illustrated with the simulation of a content addressable memory. Next, the more general case of time trajectories on a recurrent network is studied. An application is proposed in which trajectories are generated to draw letters as a function of an input. In another application of recurrent systems, a neural network certain temporal properties observed in human callosally sectioned brains. Finally the proposed algorithm for stabilizing dynamics around fixed points is extended to one for stabilizing dynamics around time trajectories. Its effects are illustrated on a network which generates Lisajous curves.

Assessing the robustness of passive scattering proton therapy with regard to local recurrence in stage III non-small cell lung cancer: a secondary analysis of a phase II trial.

PubMed

Zhu, Zhengfei; Liu, Wei; Gillin, Michael; Gomez, Daniel R; Komaki, Ritsuko; Cox, James D; Mohan, Radhe; Chang, Joe Y

2014-05-06

We assessed the robustness of passive scattering proton therapy (PSPT) plans for patients in a phase II trial of PSPT for stage III non-small cell lung cancer (NSCLC) by using the worst-case scenario method, and compared the worst-case dose distributions with the appearance of locally recurrent lesions. Worst-case dose distributions were generated for each of 9 patients who experienced recurrence after concurrent chemotherapy and PSPT to 74 Gy(RBE) for stage III NSCLC by simulating and incorporating uncertainties associated with set-up, respiration-induced organ motion, and proton range in the planning process. The worst-case CT scans were then fused with the positron emission tomography (PET) scans to locate the recurrence. Although the volumes enclosed by the prescription isodose lines in the worst-case dose distributions were consistently smaller than enclosed volumes in the nominal plans, the target dose coverage was not significantly affected: only one patient had a recurrence outside the prescription isodose lines in the worst-case plan. PSPT is a relatively robust technique. Local recurrence was not associated with target underdosage resulting from estimated uncertainties in 8 of 9 cases.

Carnot's cycle for small systems: Irreversibility and cost of operations

NASA Astrophysics Data System (ADS)

Sekimoto, Ken; Takagi, Fumiko; Hondou, Tsuyoshi

2000-12-01

In the thermodynamic limit, the existence of a maximal efficiency of energy conversion attainable by a Carnot cycle consisting of quasistatic isothermal and adiabatic processes precludes the existence of a perpetual machine of the second kind, whose cycles yield positive work in an isothermal environment. We employ the recently developed framework of the energetics of stochastic processes (called ``stochastic energetics'') to reanalyze the Carnot cycle in detail, taking account of fluctuations, without taking the thermodynamic limit. We find that in this nonmacroscopic situation both processes of connection to and disconnection from heat baths and adiabatic processes that cause distortion of the energy distribution are sources of inevitable irreversibility within the cycle. Also, the so-called null-recurrence property of the cumulative efficiency of energy conversion over many cycles and the irreversible property of isolated, purely mechanical processes under external ``macroscopic'' operations are discussed in relation to the impossibility of a perpetual machine, or Maxwell's demon. This analysis may serve as the basis for the design and analysis of mesoscopic energy converters in the near future.

Batu Pahat Driving Cycle for Light Duty Gasoline Engine

NASA Astrophysics Data System (ADS)

Zainul Abidin, Zainul Ameerul Ikhsan B.; Faisal Hushim, Mohd; Ahmad, Osman Bin

2017-08-01

Driving cycle is a series of data points that represents the vehicle speed versus time. Transient driving cycles involve many changes such as frequent speed changes during typical on-road driving condition [2]. Model driving cycles involve protracted periods at constant speeds. The Batu Pahat Driving Cycle (BPDC) developed to represent the driving pattern of people in a district of Batu Pahat. Based on this driving cycle, it will be a reference to other researchers to study about the gases emission release and fuel consumption by the vehicle on the dynamometer or automotive simulation based on this driving cycle. Existing driving cycles used such as the New European Driving Cycle (NEDC), the Federal Test Procedure (FTP-72/75, and Japan 10-15 Mode Cycle is not appropriate for Batu Pahat district because of different road conditions, driving habits and environmental of developed driving cycle countries are not same [2][14]. Batu Pahat drive cycle was developed for low-capacity gasoline engine under 150 cc and operating on urban roads, rural roads and road around Universiti Tun Hussein Onn. The importance of these driving cycle as the reference for other research to measure and do automotive simulation regarding fuel consumption and gas emission release from the motorcycle for these three type of driving cycle area. Another use for driving cycles is in vehicle simulations [3]. More specifically, they are used in propulsion system simulations to predict the performance of internal combustion engines, transmissions, electric drive systems, batteries, fuel cell systems, and similar components [18]. Data collection methods used in this study is the use of Global Positioning System (GPS). The results obtained are not similar to each other due to differences in congestion on data taken. From the driving cycle graph obtained, such as the average velocity, maximum velocity, the duration and Positive Acceleration Kinetic Energy (PKE) can be determined. In addition, the best driving cycle sample can be determined from the sum of error calculated. The least sum of error means the best driving cycle

Vapor Compression Cycle Design Program (CYCLE_D)

National Institute of Standards and Technology Data Gateway

SRD 49 NIST Vapor Compression Cycle Design Program (CYCLE_D) (PC database for purchase)   The CYCLE_D database package simulates the vapor compression refrigeration cycles. It is fully compatible with REFPROP 9.0 and covers the 62 single-compound refrigerants . Fluids can be used in mixtures comprising up to five components.

Successful resection of metachronous para-aortic, Virchow lymph node and liver metastatic recurrence of rectal cancer.

PubMed

Takeshita, Nobuyoshi; Fukunaga, Toru; Kimura, Masayuki; Sugamoto, Yuji; Tasaki, Kentaro; Hoshino, Isamu; Ota, Takumi; Maruyama, Tetsuro; Tamachi, Tomohide; Hosokawa, Takashi; Asai, Yo; Matsubara, Hisahiro

2015-11-28

A 66-year-old female presented with the main complaint of defecation trouble and abdominal distention. With diagnosis of rectal cancer, cSS, cN0, cH0, cP0, cM0 cStage II, Hartmann's operation with D3 lymph node dissection was performed and a para-aortic lymph node and a disseminated node near the primary tumor were resected. Histological examination showed moderately differentiated adenocarcinoma, pSS, pN3, pH0, pP1, pM1 (para-aortic lymph node, dissemination) fStage IV. After the operation, the patient received chemotherapy with FOLFIRI regimen. After 12 cycles of FOLFIRI regimen, computed tomography (CT) detected an 11 mm of liver metastasis in the postero-inferior segment of right hepatic lobe. With diagnosis of liver metastatic recurrence, we performed partial hepatectomy. Histological examination revealed moderately differentiated adenocarcinoma as a metastatic rectal cancer with cut end microscopically positive. After the second operation, the patient received chemotherapy with TS1 alone for 2 years. Ten months after the break, CT detected a 20 mm of para-aortic lymph node metastasis and a 10 mm of lymph node metastasis at the hepato-duodenal ligament. With diagnosis of lymph node metastatic recurrences, we performed lymph node dissection. Histological examination revealed moderately differentiated adenocarcinoma as metastatic rectal cancer in para-aortic and hepato-duodenal ligament areas. After the third operation, we started chemotherapy with modified FOLFOX6 regimen. After 2 cycles of modified FOLFOX6 regimen, due to the onset of neutropenia and liver dysfunction, we switched to capecitabine alone and continued it for 6 mo and then stopped. Eleven months after the break, CT detected two swelling 12 mm of lymph nodes at the left supraclavicular region. With diagnosis of Virchow lymph node metastatic recurrence, we started chemotherapy with capecitabine plus bevacizumab regimen. Due to the onset of neutropenia and hand foot syndrome (Grade 3), we managed to continue capecitabine administration with extension of interval period and dose reduction. After 2 years and 2 mo from starting capecitabine plus bevacizumab regimen, Virchow lymph nodes had slowly grown up to 17 mm. Because no recurrence had been detected besides Virchow lymph nodes for this follow up period, considering the side effects and quality of life, surgical resection was selected. We performed left supraclavicular lymph node dissection. Histological examination revealed moderately differentiated adenocarcinoma as a metastatic rectal cancer. After the fourth operation, the patient selected follow up without chemotherapy. Now we follow up her without recurrence and keep her quality of life high.

An Evolutionary Optimization of the Refueling Simulation for a CANDU Reactor

NASA Astrophysics Data System (ADS)

Do, Q. B.; Choi, H.; Roh, G. H.

2006-10-01

This paper presents a multi-cycle and multi-objective optimization method for the refueling simulation of a 713 MWe Canada deuterium uranium (CANDU-6) reactor based on a genetic algorithm, an elitism strategy and a heuristic rule. The proposed algorithm searches for the optimal refueling patterns for a single cycle that maximizes the average discharge burnup, minimizes the maximum channel power and minimizes the change in the zone controller unit water fills while satisfying the most important safety-related neutronic parameters of the reactor core. The heuristic rule generates an initial population of individuals very close to a feasible solution and it reduces the computing time of the optimization process. The multi-cycle optimization is carried out based on a single cycle refueling simulation. The proposed approach was verified by a refueling simulation of a natural uranium CANDU-6 reactor for an operation period of 6 months at an equilibrium state and compared with the experience-based automatic refueling simulation and the generalized perturbation theory. The comparison has shown that the simulation results are consistent from each other and the proposed approach is a reasonable optimization method of the refueling simulation that controls all the safety-related parameters of the reactor core during the simulation

A phase II study of pralatrexate with vitamin B12 and folic acid supplementation for previously treated recurrent and/or metastatic head and neck squamous cell cancer.

PubMed

Ho, Alan L; Lipson, Brynna L; Sherman, Eric J; Xiao, Han; Fury, Matthew G; Apollo, Arlyn; Seetharamu, Nagashree; Sima, Camelia S; Haque, Sofia; Lyo, John K; Sales, Roberta; Cox, Lisa; Pfister, David G

2014-06-01

Pralatrexate (Fotolyn(TM); Allos Therapeutics Inc.) is an antifolate dihydrofolate reductase (DHFR) inhibitor. We conducted a phase II study of pralatrexate with folic acid and B12 supplementation in patients with recurrent and/or metastatic head and neck squamous cell cancer (R/M HNSCC). This was a single-arm, Simon optimal two stage phase II study. Patients with R/M HNSCC previously treated with chemotherapy were eligible. The study was initiated with a dosing schedule of pralatrexate 190 mg/m(2) biweekly on a 4-week cycle with vitamin supplementation. Due to toxicity concerns, the dosing was modified to 30 mg/m(2) weekly for 3 weeks in a 4-week cycle with vitamin supplementation. Radiologic imaging was to be obtained about every 2 cycles. Thirteen subjects were enrolled; 12 were treated. Seven of the twelve patients had previously received ≥2 lines of chemotherapy. The most common grade 3 toxicity was mucositis (3 patients). Seven patients did not complete two cycles of therapy due to progression of disease (4), toxicity (1), death (1), and withdrawal of consent (1). Two deaths occurred: one due to disease progression and the other was an unwitnessed event that was possibly related to pralatrexate. No clinical activity was observed. The median overall survival was 3.1 months. The study was closed early due to lack of efficacy. Pralatrexate does not possess clinical activity against previously treated R/M HNSCC. Evaluation of pralatrexate in other clinical settings of HNSCC management with special considerations for drug toxicity may be warranted.

Quantum Model of Emerging Grammars

NASA Technical Reports Server (NTRS)

Zak, M.

1999-01-01

A special class of quantum recurrent nets simulating Markov chains with absorbing states is introduced. The absorbing states are exploited for pattern recognition: each class of patterns, each combination of patterns acquires its own meaning.

Earthquake stress drop and laboratory-inferred interseismic strength recovery

USGS Publications Warehouse

Beeler, N.M.; Hickman, S.H.; Wong, T.-F.

2001-01-01

We determine the scaling relationships between earthquake stress drop and recurrence interval tr that are implied by laboratory-measured fault strength. We assume that repeating earthquakes can be simulated by stick-slip sliding using a spring and slider block model. Simulations with static/kinetic strength, time-dependent strength, and rate- and state-variable-dependent strength indicate that the relationship between loading velocity and recurrence interval can be adequately described by the power law VL ??? trn, where n=-1. Deviations from n=-1 arise from second order effects on strength, with n>-1 corresponding to apparent time-dependent strengthening and n<-1 corresponding to weakening. Simulations with rate and state-variable equations show that dynamic shear stress drop ????d scales with recurrence as d????d/dlntr ??? ??e(b-a), where ??e is the effective normal stress, ??=??/??e, and (a-b)=d??ss/dlnV is the steady-state slip rate dependence of strength. In addition, accounting for seismic energy radiation, we suggest that the static shear stress drop ????s scales as d????s/dlntr ??? ??e(1+??)(b-a), where ?? is the fractional overshoot. The variation of ????s with lntr for earthquake stress drops is somewhat larger than implied by room temperature laboratory values of ?? and b-a. However, the uncertainty associated with the seismic data is large and the discrepancy between the seismic observations and the rate of strengthening predicted by room temperature experiments is less than an order of magnitude. Copyright 2001 by the American Geophysical Union.

Endocycles: a recurrent evolutionary innovation for post-mitotic cell growth.

PubMed

Edgar, Bruce A; Zielke, Norman; Gutierrez, Crisanto

2014-03-01

In endoreplication cell cycles, known as endocycles, cells successively replicate their genomes without segregating chromosomes during mitosis and thereby become polyploid. Such cycles, for which there are many variants, are widespread in protozoa, plants and animals. Endocycling cells can achieve ploidies of >200,000 C (chromatin-value); this increase in genomic DNA content allows a higher genomic output, which can facilitate the construction of very large cells or enhance macromolecular secretion. These cells execute normal S phases, using a G1-S regulatory apparatus similar to the one used by mitotic cells, but their capability to segregate chromosomes has been suppressed, typically by downregulation of mitotic cyclin-dependent kinase activity. Endocycles probably evolved many times, and the various endocycle mechanisms found in nature highlight the versatility of the cell cycle control machinery.

Validating the Learning Cycle Models of Business Simulation Games via Student Perceived Gains in Skills and Knowledge

ERIC Educational Resources Information Center

Tao, Yu-Hui; Yeh, C. Rosa; Hung, Kung Chin

2015-01-01

Several theoretical models have been constructed to determine the effects of buisness simulation games (BSGs) on learning performance. Although these models agree on the concept of learning-cycle effect, no empirical evidence supports the claim that the use of learning cycle activities with BSGs produces an effect on incremental gains in knowledge…

Temozolomide is an active agent in children with recurrent medulloblastoma/primitive neuroectodermal tumor: an Italian multi-institutional phase II trial

PubMed Central

Cefalo, Graziella; Massimino, Maura; Ruggiero, Antonio; Barone, Giuseppe; Ridola, Vita; Spreafico, Filippo; Potepan, Paolo; Abate, Massimo E.; Mascarin, Maurizio; Garrè, Maria Luisa; Perilongo, Giorgio; Madon, Enrico; Colosimo, Cesare; Riccardi, Riccardo

2014-01-01

Background The aim of this study was to assess the objective response rate (ORR) of children and young adults with recurrent medulloblastoma/primitive neuroectodermal tumor (MB/PNET) treated with temozolomide (TMZ). The secondary purpose was to analyze the toxicity profile of TMZ when administered orally for 5 days in 3 divided daily doses every 28 days. Methods Forty-two patients with recurrent MB/PNET, aged 21 years and younger, were recruited. Patients were treated with oral TMZ. Starting doses ranged from 120 to 200 mg/m2/day based on previous treatments. A craniospinal MRI was performed prior to the first cycle of TMZ and following every 2 cycles of treatment. Results Median age was 10 years (range, 2–21 years). Forty of 42 patients were assessed for response and toxicity. The objective response rate was 42.5%: 6 patients achieved a complete response, 11 had a partial response, and 10 had stable disease. Progression-free survival rates for all patients at 6 and 12 months were 30% and 7.5%, respectively. Their median overall survival rates at 6 and 12 months were 42.5% and 17.5%, respectively. No major extrahematological effects or life-threatening events were reported. The most common grade 3/4 toxicity included thrombocytopenia (17.5%), neutropenia (7.5%), and anemia (2.5%). Conclusions TMZ proved to be an effective agent in children and young adults with MB/PNET, heavily pre-treated, with a tolerable toxicity profile. PMID:24482446

Discovering the Complexity of Capable Faults in Northern Chile

NASA Astrophysics Data System (ADS)

Gonzalez, G.; del Río, I. A.; Rojas Orrego, C., Sr.; Astudillo, L. A., Sr.

2017-12-01

Great crustal earthquakes (Mw >7.0) in the upper plate of subduction zones are relatively uncommon and less well documented. We hypothesize that crustal earthquakes are poorly represented in the instrumental record because they have long recurrence intervals. In northern Chile, the extreme long-term aridity permits extraordinary preservation of landforms related to fault activity, making this region a primary target to understand how upper plate faults work at subduction zones. To understand how these faults relate to crustal seismicity in the long-term, we have conducted a detailed palaeoseismological study. We performed a palaeoseismological survey integrating trench logging and photogrammetry based on UAVs. Optically stimulated luminescence (OSL) age determinations were practiced for dating deposits linked to faulting. In this contribution we present the study case of two primary faults located in the Coastal Cordillera of northern Chile between Iquique (21ºS) and Antofagasta (24ºS). We estimate the maximum moment magnitude of earthquakes generated in these upper plate faults, their recurrence interval and the fault-slip rate. We conclude that the studied upper plate faults show a complex kinematics on geological timescales. Faults seem to change their kinematics from normal (extension) to reverse (compression) or from normal to transcurrent (compression) according to the stage of subduction earthquake cycle. Normal displacement is related to coseismic stages and compression is linked to interseismic period. As result this complex interaction these faults are capable of generating Mw 7.0 earthquakes, with recurrence times on the order of thousands of years during every stage of the subduction earthquake cycle.

CIR-XL recurring for several years

NASA Astrophysics Data System (ADS)

Dósa, Melinda; Erdös, Géza

2016-04-01

The heliospheric magnetic flux is determined from the radial component of the magnetic field vector measured onboard interplanetary space probes. Earlier Ulysses research has shown remarkable independence of the flux from heliographic latitude. Here we are investigating whether any longitudinal variation exist in the 50 year long OMNI magnetic data set. When determining the heliographic longitude of the plasma source, correction was applied for the solar wind travel time. Significant recurrent enhancements of the magnetic flux was observed during the declining phase of the solar cycles. These flux enhancements are associated with co-rotating interaction regions (CIR) lasting several years. The recurrence period is slightly faster than the Carrington Rotation rate. The same, long lasting recurring features can be observed when plotting the deviation angle of the solar wind velocity vector from the radial direction. However, the deviation angle is small - in order of a few degrees - and cannot account for the observed flux increases. An increase of the magnetic field is clearly caused by the plasma compression associated to CIRs. Comparing interplanetary data with synoptic maps of the coronal magnetic field (PFSS modell) and coronal temperature data of ACE, we came to the possible explanation that these long-term structures are caused by fast speed solar wind originating from coronal holes. This results supports the idea that magnetic field lines from coronal holes spread out and reach to low latitudes as well. The recurrent longitudinal variation of the magnetic flux during the declining phase of the solar cycle has impact on the modulation of cosmic rays as well as on the frequency and intensity of space weather events.

Multicystic dedifferentiated retroperitoneal liposarcoma: tumour cyst fluid analysis and implications for management

PubMed Central

Khoury, Mitri; Sim, Geok Choo; Harao, Michiko; Radvanyi, Laszlo; Amini, Behrang; Benjamin, Robert S; Pisters, Peter W T; Pollock, Raphael E; Tseng, William W

2015-01-01

Liposarcomas are soft tissue sarcomas of adipocyte origin. We describe a case of a dedifferentiated retroperitoneal liposarcoma with an unusual presentation on recurrence as a large, multicystic tumour. The patient was a 72-year-old woman who had undergone multiple treatments including two prior resections. For her most recent locoregional disease recurrence, the patient was offered surgical debulking for symptom palliation. At this operation, performed after two cycles of chemotherapy, the tumour cyst fluid was analysed and found to have a predominance of immune cells with no identifiable malignant cells. This case and the results of our tumour cyst fluid analysis raise several interesting considerations for the management of this unique situation in a rare disease. PMID:26156843

Multicystic dedifferentiated retroperitoneal liposarcoma: tumour cyst fluid analysis and implications for management.

PubMed

Khoury, Mitri; Sim, Geok Choo; Harao, Michiko; Radvanyi, Laszlo; Amini, Behrang; Benjamin, Robert S; Pisters, Peter W T; Pollock, Raphael E; Tseng, William W

2015-07-08

Liposarcomas are soft tissue sarcomas of adipocyte origin. We describe a case of a dedifferentiated retroperitoneal liposarcoma with an unusual presentation on recurrence as a large, multicystic tumour. The patient was a 72-year-old woman who had undergone multiple treatments including two prior resections. For her most recent locoregional disease recurrence, the patient was offered surgical debulking for symptom palliation. At this operation, performed after two cycles of chemotherapy, the tumour cyst fluid was analysed and found to have a predominance of immune cells with no identifiable malignant cells. This case and the results of our tumour cyst fluid analysis raise several interesting considerations for the management of this unique situation in a rare disease. 2015 BMJ Publishing Group Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kochunas, Brendan; Collins, Benjamin; Stimpson, Shane

This paper describes the methodology developed and implemented in the Virtual Environment for Reactor Applications Core Simulator (VERA-CS) to perform high-fidelity, pressurized water reactor (PWR), multicycle, core physics calculations. Depletion of the core with pin-resolved power and nuclide detail is a significant advance in the state of the art for reactor analysis, providing the level of detail necessary to address the problems of the U.S. Department of Energy Nuclear Reactor Simulation Hub, the Consortium for Advanced Simulation of Light Water Reactors (CASL). VERA-CS has three main components: the neutronics solver MPACT, the thermal-hydraulic (T-H) solver COBRA-TF (CTF), and the nuclidemore » transmutation solver ORIGEN. This paper focuses on MPACT and provides an overview of the resonance self-shielding methods, macroscopic-cross-section calculation, two-dimensional/one-dimensional (2-D/1-D) transport, nuclide depletion, T-H feedback, and other supporting methods representing a minimal set of the capabilities needed to simulate high-fidelity models of a commercial nuclear reactor. Results are presented from the simulation of a model of the first cycle of Watts Bar Unit 1. The simulation is within 16 parts per million boron (ppmB) reactivity for all state points compared to cycle measurements, with an average reactivity bias of <5 ppmB for the entire cycle. Comparisons to cycle 1 flux map data are also provided, and the average 2-D root-mean-square (rms) error during cycle 1 is 1.07%. To demonstrate the multicycle capability, a state point at beginning of cycle (BOC) 2 was also simulated and compared to plant data. The comparison of the cycle 2 BOC state has a reactivity difference of +3 ppmB from measurement, and the 2-D rms of the comparison in the flux maps is 1.77%. Lastly, these results provide confidence in VERA-CS’s capability to perform high-fidelity calculations for practical PWR reactor problems.« less

Nonlinear Interactions between Climate and Atmospheric Carbon Dioxide Drivers of Terrestrial and Marine Carbon Cycle Changes

NASA Astrophysics Data System (ADS)

Hoffman, F. M.; Randerson, J. T.; Moore, J. K.; Goulden, M.; Fu, W.; Koven, C.; Swann, A. L. S.; Mahowald, N. M.; Lindsay, K. T.; Munoz, E.

2017-12-01

Quantifying interactions between global biogeochemical cycles and the Earth system is important for predicting future atmospheric composition and informing energy policy. We applied a feedback analysis framework to three sets of Historical (1850-2005), Representative Concentration Pathway 8.5 (2006-2100), and its extension (2101-2300) simulations from the Community Earth System Model version 1.0 (CESM1(BGC)) to quantify drivers of terrestrial and ocean responses of carbon uptake. In the biogeochemically coupled simulation (BGC), the effects of CO2 fertilization and nitrogen deposition influenced marine and terrestrial carbon cycling. In the radiatively coupled simulation (RAD), the effects of rising temperature and circulation changes due to radiative forcing from CO2, other greenhouse gases, and aerosols were the sole drivers of carbon cycle changes. In the third, fully coupled simulation (FC), both the biogeochemical and radiative coupling effects acted simultaneously. We found that climate-carbon sensitivities derived from RAD simulations produced a net ocean carbon storage climate sensitivity that was weaker and a net land carbon storage climate sensitivity that was stronger than those diagnosed from the FC and BGC simulations. For the ocean, this nonlinearity was associated with warming-induced weakening of ocean circulation and mixing that limited exchange of dissolved inorganic carbon between surface and deeper water masses. For the land, this nonlinearity was associated with strong gains in gross primary production in the FC simulation, driven by enhancements in the hydrological cycle and increased nutrient availability. We developed and applied a nonlinearity metric to rank model responses and driver variables. The climate-carbon cycle feedback gain at 2300 was 42% higher when estimated from climate-carbon sensitivities derived from the difference between FC and BGC than when derived from RAD. We re-analyzed other CMIP5 model results to quantify the effects of such nonlinearities on their projected climate-carbon cycle feedback gains.

Modelling the pelagic nitrogen cycle and vertical particle flux in the Norwegian sea

NASA Astrophysics Data System (ADS)

Haupt, Olaf J.; Wolf, Uli; v. Bodungen, Bodo

1999-02-01

A 1D Eulerian ecosystem model (BIological Ocean Model) for the Norwegian Sea was developed to investigate the dynamics of pelagic ecosystems. The BIOM combines six biochemical compartments and simulates the annual nitrogen cycle with specific focus on production, modification and sedimentation of particles in the water column. The external forcing and physical framework is based on a simulated annual cycle of global radiation and an annual mixed-layer cycle derived from field data. The vertical resolution of the model is given by an exponential grid with 200 depth layers, allowing specific parameterization of various sinking velocities, breakdown of particles and the remineralization processes. The aim of the numerical experiments is the simulation of ecosystem dynamics considering the specific biogeochemical properties of the Norwegian Sea, for example the life cycle of the dominant copepod Calanus finmarchicus. The results of the simulations were validated with field data. Model results are in good agreement with field data for the lower trophic levels of the food web. With increasing complexity of the organisms the differences increase between simulated processes and field data. Results of the numerical simulations suggest that BIOM is well adapted to investigate a physically controlled ecosystem. The simulation of grazing controlled pelagic ecosystems, like the Norwegian Sea, requires adaptations of parameterization to the specific ecosystem features. By using seasonally adaptation of the most sensible processes like utilization of light by phytoplankton and grazing by zooplankton results were greatly improved.

Performance evaluation of CESM in simulating the dust cycle

NASA Astrophysics Data System (ADS)

Parajuli, S. P.; Yang, Z. L.; Kocurek, G.; Lawrence, D. M.

2014-12-01

Mineral dust in the atmosphere has implications for Earth's radiation budget, biogeochemical cycles, hydrological cycles, human health and visibility. Mineral dust is injected into the atmosphere during dust storms when the surface winds are sufficiently strong and the land surface conditions are favorable. Dust storms are very common in specific regions of the world including the Middle East and North Africa (MENA) region, which contains more than 50% of the global dust sources. In this work, we present simulation of the dust cycle under the framework of CESM1.2.2 and evaluate how well the model captures the spatio-temporal characteristics of dust sources, transport and deposition at global scale, especially in dust source regions. We conducted our simulations using two existing erodibility maps (geomorphic and topographic) and a new erodibility map, which is based on the correlation between observed wind and dust. We compare the simulated results with MODIS satellite data, MACC reanalysis data, and AERONET station data. Comparison with MODIS satellite data and MACC reanalysis data shows that all three erodibility maps generally reproduce the spatio-temporal characteristics of dust optical depth globally. However, comparison with AERONET station data shows that the simulated dust optical depth is generally overestimated for all erodibility maps. Results vary greatly by region and scale of observational data. Our results also show that the simulations forced by reanalysis meteorology capture the overall dust cycle more realistically compared to the simulations done using online meteorology.

Reconstructing Genetic Regulatory Networks Using Two-Step Algorithms with the Differential Equation Models of Neural Networks.

PubMed

Chen, Chi-Kan

2017-07-26

The identification of genetic regulatory networks (GRNs) provides insights into complex cellular processes. A class of recurrent neural networks (RNNs) captures the dynamics of GRN. Algorithms combining the RNN and machine learning schemes were proposed to reconstruct small-scale GRNs using gene expression time series. We present new GRN reconstruction methods with neural networks. The RNN is extended to a class of recurrent multilayer perceptrons (RMLPs) with latent nodes. Our methods contain two steps: the edge rank assignment step and the network construction step. The former assigns ranks to all possible edges by a recursive procedure based on the estimated weights of wires of RNN/RMLP (RE RNN /RE RMLP ), and the latter constructs a network consisting of top-ranked edges under which the optimized RNN simulates the gene expression time series. The particle swarm optimization (PSO) is applied to optimize the parameters of RNNs and RMLPs in a two-step algorithm. The proposed RE RNN -RNN and RE RMLP -RNN algorithms are tested on synthetic and experimental gene expression time series of small GRNs of about 10 genes. The experimental time series are from the studies of yeast cell cycle regulated genes and E. coli DNA repair genes. The unstable estimation of RNN using experimental time series having limited data points can lead to fairly arbitrary predicted GRNs. Our methods incorporate RNN and RMLP into a two-step structure learning procedure. Results show that the RE RMLP using the RMLP with a suitable number of latent nodes to reduce the parameter dimension often result in more accurate edge ranks than the RE RNN using the regularized RNN on short simulated time series. Combining by a weighted majority voting rule the networks derived by the RE RMLP -RNN using different numbers of latent nodes in step one to infer the GRN, the method performs consistently and outperforms published algorithms for GRN reconstruction on most benchmark time series. The framework of two-step algorithms can potentially incorporate with different nonlinear differential equation models to reconstruct the GRN.

Characterization of dynamical systems under noise using recurrence networks: Application to simulated and EEG data

NASA Astrophysics Data System (ADS)

Puthanmadam Subramaniyam, Narayan; Hyttinen, Jari

2014-10-01

In this letter, we study the influence of observational noise on recurrence network (RN) measures, the global clustering coefficient (C) and average path length (L) using the Rössler system and propose the application of RN measures to analyze the structural properties of electroencephalographic (EEG) data. We find that for an appropriate recurrence rate (RR>0.02) the influence of noise on C can be minimized while L is independent of RR for increasing levels of noise. Indications of structural complexity were found for healthy EEG, but to a lesser extent than epileptic EEG. Furthermore, C performed better than L in case of epileptic EEG. Our results show that RN measures can provide insights into the structural properties of EEG in normal and pathological states.

EG-07CELL CYCLE SIGNATURE AND TUMOR PHYLOGENY ARE ENCODED IN THE EVOLUTIONARY DYNAMICS OF DNA METHYLATION IN GLIOMA

PubMed Central

Mazor, Tali; Pankov, Aleksandr; Johnson, Brett E.; Hong, Chibo; Bell, Robert J.A.; Smirnov, Ivan V.; Reis, Gerald F.; Phillips, Joanna J.; Barnes, Michael; Bollen, Andrew W.; Taylor, Barry S.; Molinaro, Annette M.; Olshen, Adam B.; Song, Jun S.; Berger, Mitchel S.; Chang, Susan M.; Costello, Joseph F.

2014-01-01

The clonal evolution of tumor cell populations can be reconstructed from patterns of genetic alterations. In contrast, tumor epigenetic states, including DNA methylation, are reversible and sensitive to the tumor microenvironment, presumably precluding the use of epigenetics to discover tumor phylogeny. Here we examined the spatial and temporal dynamics of DNA methylation in a clinically and genetically characterized cohort of IDH1-mutant low-grade gliomas and their patient-matched recurrences. WHO grade II gliomas are diffuse, infiltrative tumors that frequently recur and may undergo malignant progression to a higher grade with a worse prognosis. The extent to which epigenetic alterations contribute to the evolution of low-grade gliomas, including malignant progression, is unknown. While all gliomas in the cohort exhibited the hypermethylation signature associated with IDH1 mutation, low-grade gliomas that underwent malignant progression to high-grade glioblastoma (GBM) had a unique signature of DNA hypomethylation enriched for active enhancers, as well as sites of age-related hypermethylation in the brain. Genes with promoter hypomethylation and concordant transcriptional upregulation during evolution to GBM were enriched in cell cycle function, evolving in concert with genetic alterations that deregulate the G1/S cell cycle checkpoint. Despite the plasticity of tumor epigenetic states, phyloepigenetic trees robustly recapitulated phylogenetic trees derived from somatic mutations in the same patients. These findings highlight widespread co-dependency of genetic and epigenetic events throughout the clonal evolution of initial and recurrent glioma.

Two cycles of recurrent maternal half-sib selection reduce foliar late blight in a diploid hybrid Solanum phureja-S. stenotomum population by two-thirds

USDA-ARS?s Scientific Manuscript database

Foliar late blight, caused by Phytophthora infestans, is an important disease problem worldwide. Foliar resistance to late blight was found in a hybrid population of the cultivated diploid species Solanum phureja-S. stenotomum (phu-stn). The objective of this study was to determine if resistance t...

Computational Simulation of the Activation Cycle of Gα Subunit in the G Protein Cycle Using an Elastic Network Model

PubMed Central

Kim, Min Hyeok; Kim, Young Jin; Kim, Hee Ryung; Jeon, Tae-Joon; Choi, Jae Boong; Chung, Ka Young; Kim, Moon Ki

2016-01-01

Agonist-activated G protein-coupled receptors (GPCRs) interact with GDP-bound G protein heterotrimers (Gαβγ) promoting GDP/GTP exchange, which results in dissociation of Gα from the receptor and Gβγ. The GTPase activity of Gα hydrolyzes GTP to GDP, and the GDP-bound Gα interacts with Gβγ, forming a GDP-bound G protein heterotrimer. The G protein cycle is allosterically modulated by conformational changes of the Gα subunit. Although biochemical and biophysical methods have elucidated the structure and dynamics of Gα, the precise conformational mechanisms underlying the G protein cycle are not fully understood yet. Simulation methods could help to provide additional details to gain further insight into G protein signal transduction mechanisms. In this study, using the available X-ray crystal structures of Gα, we simulated the entire G protein cycle and described not only the steric features of the Gα structure, but also conformational changes at each step. Each reference structure in the G protein cycle was modeled as an elastic network model and subjected to normal mode analysis. Our simulation data suggests that activated receptors trigger conformational changes of the Gα subunit that are thermodynamically favorable for opening of the nucleotide-binding pocket and GDP release. Furthermore, the effects of GTP binding and hydrolysis on mobility changes of the C and N termini and switch regions are elucidated. In summary, our simulation results enabled us to provide detailed descriptions of the structural and dynamic features of the G protein cycle. PMID:27483005

Influence of Thermal Cycling on Flexural Properties and Simulated Wear of Computer-aided Design/Computer-aided Manufacturing Resin Composites.

PubMed

Tsujimoto, A; Barkmeier, W W; Takamizawa, T; Latta, M A; Miyazaki, M

The purpose of this study was to evaluate the influence of thermal cycling on the flexural properties and simulated wear of computer-aided design/computer-aided manufacturing (CAD/CAM) resin composites. The six CAD/CAM resin composites used in this study were 1) Lava Ultimate CAD/CAM Restorative (LU); 2) Paradigm MZ100 (PM); 3) CERASMART (CS); 4) Shofu Block HC (SB); 5) KATANA AVENCIA Block (KA); and 6) VITA ENAMIC (VE). Specimens were divided randomly into two groups, one of which was stored in distilled water for 24 hours, and the other of which was subjected to 10,000 thermal cycles. For each material, 15 specimens from each group were used to determine the flexural strength and modulus according to ISO 6872, and 20 specimens from each group were used to examine wear using a localized wear simulation model. The test materials were subjected to a wear challenge of 400,000 cycles in a Leinfelder-Suzuki device (Alabama machine). The materials were placed in custom-cylinder stainless steel fixtures, and simulated localized wear was generated using a stainless steel ball bearing (r=2.387 mm) antagonist in a water slurry of polymethyl methacrylate beads. Simulated wear was determined using a noncontact profilometer (Proscan 2100) with Proscan and AnSur 3D software. The two-way analysis of variance of flexural properties and simulated wear of CAD/CAM resin composites revealed that material type and thermal cycling had a significant influence (p<0.05), but there was no significant interaction (p>0.05) between the two factors. The flexural properties and maximum depth of wear facets of CAD/CAM resin composite were different (p<0.05) depending on the material, and their values were influenced (p>0.05) by thermal cycling, except in the case of VE. The volume losses in wear facets on LU, PM, and SB after 10,000 thermal cycles were significantly higher (p<0.05) than those after 24 hours of water storage, unlike CS, KA, and VE. The results of this study indicate that the flexural properties and simulated wear of CAD/CAM resin composites are different depending on the material. In addition, the flexural properties and simulated wear of CAD/CAM resin composites are influenced by thermal cycling.

Joint scale-change models for recurrent events and failure time.

PubMed

Xu, Gongjun; Chiou, Sy Han; Huang, Chiung-Yu; Wang, Mei-Cheng; Yan, Jun

2017-01-01

Recurrent event data arise frequently in various fields such as biomedical sciences, public health, engineering, and social sciences. In many instances, the observation of the recurrent event process can be stopped by the occurrence of a correlated failure event, such as treatment failure and death. In this article, we propose a joint scale-change model for the recurrent event process and the failure time, where a shared frailty variable is used to model the association between the two types of outcomes. In contrast to the popular Cox-type joint modeling approaches, the regression parameters in the proposed joint scale-change model have marginal interpretations. The proposed approach is robust in the sense that no parametric assumption is imposed on the distribution of the unobserved frailty and that we do not need the strong Poisson-type assumption for the recurrent event process. We establish consistency and asymptotic normality of the proposed semiparametric estimators under suitable regularity conditions. To estimate the corresponding variances of the estimators, we develop a computationally efficient resampling-based procedure. Simulation studies and an analysis of hospitalization data from the Danish Psychiatric Central Register illustrate the performance of the proposed method.

A comparison of the effect of short-term aromatase inhibitor (letrozole) and GnRH agonist (triptorelin) versus case control on pregnancy rate and symptom and sign recurrence after laparoscopic treatment of endometriosis.

PubMed

Alborzi, Saeed; Hamedi, Bahareh; Omidvar, Azizeh; Dehbashi, Sedigheh; Alborzi, Soroosh; Alborzi, Mehrnoosh

2011-07-01

To compare the role of an aromatase inhibitor (letrozole) with a GnRH agonist (triptorelin) versus case control on the pregnancy rate and recurrence of symptoms and signs in patients with endometriosis. In a prospective randomized clinical trial, after treatment of 144 infertile women in their reproductive age by laparoscopy (whose endometriosis was confirmed by prior laparoscopy), they were divided into 3 groups: group 1 (47 cases) who received letrozole for 2 months, group 2 (40 patients) who were prescribed triptorelin for 2 months and group 3 who were 57 patients in the control group and did not receive any medication. We followed up each group at least for 12 months after their restoration of regular cycle. Pregnancy rate was 23.4% in group 1, 27.5% in group 2, and 28.1% in group 3. The results did not show significant differences among the 3 groups. Recurrence rate of endometriosis was 6.4% in group 1, 5% group 2 and 5.3% in group 3, which was not statistically significantly different as well. Pregnancy rate and endometriosis recurrence rate are comparable among the 3 groups.

Chilean megathrust earthquake recurrence linked to frictional contrast at depth

NASA Astrophysics Data System (ADS)

Moreno, M.; Li, S.; Melnick, D.; Bedford, J. R.; Baez, J. C.; Motagh, M.; Metzger, S.; Vajedian, S.; Sippl, C.; Gutknecht, B. D.; Contreras-Reyes, E.; Deng, Z.; Tassara, A.; Oncken, O.

2018-04-01

Fundamental processes of the seismic cycle in subduction zones, including those controlling the recurrence and size of great earthquakes, are still poorly understood. Here, by studying the 2016 earthquake in southern Chile—the first large event within the rupture zone of the 1960 earthquake (moment magnitude (Mw) = 9.5)—we show that the frictional zonation of the plate interface fault at depth mechanically controls the timing of more frequent, moderate-size deep events (Mw < 8) and less frequent, tsunamigenic great shallow earthquakes (Mw > 8.5). We model the evolution of stress build-up for a seismogenic zone with heterogeneous friction to examine the link between the 2016 and 1960 earthquakes. Our results suggest that the deeper segments of the seismogenic megathrust are weaker and interseismically loaded by a more strongly coupled, shallower asperity. Deeper segments fail earlier ( 60 yr recurrence), producing moderate-size events that precede the failure of the shallower region, which fails in a great earthquake (recurrence >110 yr). We interpret the contrasting frictional strength and lag time between deeper and shallower earthquakes to be controlled by variations in pore fluid pressure. Our integrated analysis strengthens understanding of the mechanics and timing of great megathrust earthquakes, and therefore could aid in the seismic hazard assessment of other subduction zones.

Integrated Turbine-Based Combined Cycle Dynamic Simulation Model

NASA Technical Reports Server (NTRS)

Haid, Daniel A.; Gamble, Eric J.

2011-01-01

A Turbine-Based Combined Cycle (TBCC) dynamic simulation model has been developed to demonstrate all modes of operation, including mode transition, for a turbine-based combined cycle propulsion system. The High Mach Transient Engine Cycle Code (HiTECC) is a highly integrated tool comprised of modules for modeling each of the TBCC systems whose interactions and controllability affect the TBCC propulsion system thrust and operability during its modes of operation. By structuring the simulation modeling tools around the major TBCC functional modes of operation (Dry Turbojet, Afterburning Turbojet, Transition, and Dual Mode Scramjet) the TBCC mode transition and all necessary intermediate events over its entire mission may be developed, modeled, and validated. The reported work details the use of the completed model to simulate a TBCC propulsion system as it accelerates from Mach 2.5, through mode transition, to Mach 7. The completion of this model and its subsequent use to simulate TBCC mode transition significantly extends the state-of-the-art for all TBCC modes of operation by providing a numerical simulation of the systems, interactions, and transient responses affecting the ability of the propulsion system to transition from turbine-based to ramjet/scramjet-based propulsion while maintaining constant thrust.

Dynamic process of high-current vacuum arc with consideration of magnetic field delay: numerical simulation and comparisons with the experiments

NASA Astrophysics Data System (ADS)

Yang, Dingge; Wang, Lijun; Jia, Shenli; Huo, Xintao; Zhang, Ling; Liu, Ke; Shi, Zongqian

2009-03-01

Based on a two-dimensional magnetohydrodynamic model, the dynamic process in a high-current vacuum arc (as in a high-power circuit breaker) was simulated and analysed. A half-wave of sinusoidal current was represented as a series of discrete steps, rather than as a continuous wave. The simulation was done at each step, i.e. at each of the discrete current values. In the simulation, the phase delay by which the axial magnetic field lags the current was taken into account. The curves which represent the variation of arc parameters (such as electron temperature) look sinusoidal, but the parameter values at a discrete moment in the second 1/4 cycle are smaller than those at the corresponding moment in the first 1/4 cycle (although the currents are equal at these two moments). This is perhaps mainly due to the magnetic field delay. In order to verify the correctness of the simulation, the simulation results were compared in part with the experimental results. It was seen from the experimental results that the arc column was darker but more uniform in the second 1/4 cycle than in the first 1/4 cycle, in agreement with the simulation results.

Engine cylinder pressure reconstruction using crank kinematics and recurrently-trained neural networks

NASA Astrophysics Data System (ADS)

Bennett, C.; Dunne, J. F.; Trimby, S.; Richardson, D.

2017-02-01

A recurrent non-linear autoregressive with exogenous input (NARX) neural network is proposed, and a suitable fully-recurrent training methodology is adapted and tuned, for reconstructing cylinder pressure in multi-cylinder IC engines using measured crank kinematics. This type of indirect sensing is important for cost effective closed-loop combustion control and for On-Board Diagnostics. The challenge addressed is to accurately predict cylinder pressure traces within the cycle under generalisation conditions: i.e. using data not previously seen by the network during training. This involves direct construction and calibration of a suitable inverse crank dynamic model, which owing to singular behaviour at top-dead-centre (TDC), has proved difficult via physical model construction, calibration, and inversion. The NARX architecture is specialised and adapted to cylinder pressure reconstruction, using a fully-recurrent training methodology which is needed because the alternatives are too slow and unreliable for practical network training on production engines. The fully-recurrent Robust Adaptive Gradient Descent (RAGD) algorithm, is tuned initially using synthesised crank kinematics, and then tested on real engine data to assess the reconstruction capability. Real data is obtained from a 1.125 l, 3-cylinder, in-line, direct injection spark ignition (DISI) engine involving synchronised measurements of crank kinematics and cylinder pressure across a range of steady-state speed and load conditions. The paper shows that a RAGD-trained NARX network using both crank velocity and crank acceleration as input information, provides fast and robust training. By using the optimum epoch identified during RAGD training, acceptably accurate cylinder pressures, and especially accurate location-of-peak-pressure, can be reconstructed robustly under generalisation conditions, making it the most practical NARX configuration and recurrent training methodology for use on production engines.

Green supply chain: Simulating road traffic congestion

NASA Astrophysics Data System (ADS)

Jalal, Muhammad Zulqarnain Hakim Abd; Nawawi, Mohd Kamal Mohd; Laailatul Hanim Mat Desa, Wan; Khalid, Ruzelan; Khalid Abduljabbar, Waleed; Ramli, Razamin

2017-09-01

With the increasing awareness of the consumers about environmental issues, businesses, households and governments increasingly want use green products and services which lead to green supply chain. This paper discusses a simulation study of a selected road traffic system that will contribute to the air pollution if in the congestion state. Road traffic congestion (RTC) can be caused by a temporary obstruction, a permanent capacity bottleneck in the network itself, and stochastic fluctuation in demand within a particular sector of the network, leading to spillback and queue propagation. A discrete-event simulation model is developed to represent the real traffic light control (TLC) system condition during peak hours. Certain performance measures such as average waiting time and queue length were measured using the simulation model. Existing system uses pre-set cycle time to control the light changes which is fixed time cycle. In this research, we test several other combination of pre-set cycle time with the objective to find the best system. In addition, we plan to use a combination of the pre-set cycle time and a proximity sensor which have the authority to manipulate the cycle time of the lights. The sensors work in such situation when the street seems to have less occupied vehicles, obviously it may not need a normal cycle for green light, and automatically change the cycle to street where vehicle is present.

Simulation of a combined-cycle engine

NASA Technical Reports Server (NTRS)

Vangerpen, Jon

1991-01-01

A FORTRAN computer program was developed to simulate the performance of combined-cycle engines. These engines combine features of both gas turbines and reciprocating engines. The computer program can simulate both design point and off-design operation. Widely varying engine configurations can be evaluated for their power, performance, and efficiency as well as the influence of altitude and air speed. Although the program was developed to simulate aircraft engines, it can be used with equal success for stationary and automative applications.

Characteristics of aperiodic sequence of slip events caused by interaction between seismic patches and that caused be self-organized stress heterogeneity

NASA Astrophysics Data System (ADS)

Kato, N.

2017-12-01

Numerical simulations of earthquake cycles are conducted to investigate the origin of complexity of earthquake recurrence. There are two main causes of the complexity. One is self-organized stress heterogeneity due to dynamical effect. The other is the effect of interaction between some fault patches. In the model, friction on the fault is assumed to obey a rate- and state-dependent friction law. Circular patches of velocity-weakening frictional property are assumed on the fault. On the remaining areas of the fault, velocity-strengthening friction is assumed. We consider three models: Single patch model, two-patch model, and three-patch model. In the first model, the dynamical effect is mainly examined. The latter two models take into consideration the effect of interaction as well as the dynamical effect. Complex multiperiodic or aperiodic sequences of slip events occur when slip behavior changes from the seismic to aseismic, and when the degree of interaction between seismic patches is intermediate. The former is observed in all the models, and the latter is observed in the two-patch model and the three-patch model. Evolution of spatial distribution of shear stress on the fault suggests that aperiodicity at the transition from seismic to aseismic slip is caused by self-organized stress heterogeneity. The iteration maps of recurrence intervals of slip events in aperiodic sequences are examined, and they are approximately expressed by simple curves for aperiodicity at the transition from seismic to aseismic slip. In contrast, the iteration maps for aperiodic sequences caused by interaction between seismic patches are scattered and they are not expressed by simple curves. This result suggests that complex sequences caused by different mechanisms may be distinguished.

Cost-effectiveness analysis of neurocognitive-sparing treatments for brain metastases.

PubMed

Savitz, Samuel T; Chen, Ronald C; Sher, David J

2015-12-01

Decisions regarding how to treat patients who have 1 to 3 brain metastases require important tradeoffs between controlling recurrences, side effects, and costs. In this analysis, the authors compared novel treatments versus usual care to determine the incremental cost-effectiveness ratio from a payer's (Medicare) perspective. Cost-effectiveness was evaluated using a microsimulation of a Markov model for 60 one-month cycles. The model used 4 simulated cohorts of patients aged 65 years with 1 to 3 brain metastases. The 4 cohorts had a median survival of 3, 6, 12, and 24 months to test the sensitivity of the model to different prognoses. The treatment alternatives evaluated included stereotactic radiosurgery (SRS) with 3 variants of salvage after recurrence (whole-brain radiotherapy [WBRT], hippocampal avoidance WBRT [HA-WBRT], SRS plus WBRT, and SRS plus HA-WBRT). The findings were tested for robustness using probabilistic and deterministic sensitivity analyses. Traditional radiation therapies remained cost-effective for patients in the 3-month and 6-month cohorts. In the cohorts with longer median survival, HA-WBRT and SRS plus HA-WBRT became cost-effective relative to traditional treatments. When the treatments that involved HA-WBRT were excluded, either SRS alone or SRS plus WBRT was cost-effective relative to WBRT alone. The deterministic and probabilistic sensitivity analyses confirmed the robustness of these results. HA-WBRT and SRS plus HA-WBRT were cost-effective for 2 of the 4 cohorts, demonstrating the value of controlling late brain toxicity with this novel therapy. Cost-effectiveness depended on patient life expectancy. SRS was cost-effective in the cohorts with short prognoses (3 and 6 months), whereas HA-WBRT and SRS plus HA-WBRT were cost-effective in the cohorts with longer prognoses (12 and 24 months). © 2015 American Cancer Society.

Novel hydroxyapatite nanorods improve anti-caries efficacy of enamel infiltrants.

PubMed

Andrade Neto, D M; Carvalho, E V; Rodrigues, E A; Feitosa, V P; Sauro, S; Mele, G; Carbone, L; Mazzetto, S E; Rodrigues, L K; Fechine, P B A

2016-06-01

Enamel resin infiltrants are biomaterials able to treat enamel caries at early stages. Nevertheless, they cannot prevent further demineralization of mineral-depleted enamel. Therefore, the aim of this work was to synthesize and incorporate specific hydroxyapatite nanoparticles (HAps) into the resin infiltrant to overcome this issue. HAps were prepared using a hydrothermal method (0h, 2h and 5h). The crystallinity, crystallite size and morphology of the nanoparticles were characterized through XRD, FT-IR and TEM. HAps were then incorporated (10wt%) into a light-curing co-monomer resin blend (control) to create different resin-based enamel infiltrants (HAp-0h, HAp-2h and HAp-5h), whose degree of conversion (DC) was assessed by FT-IR. Enamel caries lesions were first artificially created in extracted human molars and infiltrated using the tested resin infiltrants. Specimens were submitted to pH-cycling to simulate recurrent caries. Knoop microhardness of resin-infiltrated underlying and surrounding enamel was analyzed before and after pH challenge. Whilst HAp-0h resulted amorphous, HAp-2h and HAp-5h presented nanorod morphology and higher crystallinity. Resin infiltration doped with HAp-2h and HAp-5h caused higher enamel resistance against demineralization compared to control HAp-free and HAp-0h infiltration. The inclusion of more crystalline HAp nanorods (HAp-2h and HAp-5h) increased significantly (p<0.05) the DC. Incorporation of more crystalline HAp nanorods into enamel resin infiltrants may be a feasible method to improve the overall performance in the prevention of recurrent demineralization (e.g. caries lesion) in resin-infiltrated enamel. Copyright © 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Mathematical modelling of radiotherapy strategies for early breast cancer.

PubMed

Enderling, Heiko; Anderson, Alexander R A; Chaplain, Mark A J; Munro, Alastair J; Vaidya, Jayant S

2006-07-07

Targeted intraoperative radiotherapy (Targit) is a new concept of partial breast irradiation where single fraction radiotherapy is delivered directly to the tumour bed. Apart from logistic advantages, this strategy minimizes the risk of missing the tumour bed and avoids delay between surgery and radiotherapy. It is presently being compared with the standard fractionated external beam radiotherapy (EBRT) in randomized trials. In this paper we present a mathematical model for the growth and invasion of a solid tumour into a domain of tissue (in this case breast tissue), and then a model for surgery and radiation treatment of this tumour. We use the established linear-quadratic (LQ) model to compute the survival probabilities for both tumour cells and irradiated breast tissue and then simulate the effects of conventional EBRT and Targit. True local recurrence of the tumour could arise either from stray tumour cells, or the tumour bed that harbours morphologically normal cells having a predisposition to genetic changes, such as a loss of heterozygosity (LOH) in genes that are crucial for tumourigenesis, e.g. tumour suppressor genes (TSGs). Our mathematical model predicts that the single high dose of radiotherapy delivered by Targit would result in eliminating all these sources of recurrence, whereas the fractionated EBRT would eliminate stray tumour cells, but allow (by virtue of its very schedule) the cells with LOH in TSGs or cell-cycle checkpoint genes to pass on low-dose radiation-induced DNA damage and consequently mutations that may favour the development of a new tumour. The mathematical model presented here is an initial attempt to model a biologically complex phenomenon that has until now received little attention in the literature and provides a 'proof of principle' that it is possible to produce clinically testable hypotheses on the effects of different approaches of radiotherapy for breast cancer.

Simulation of the M13 life cycle I: Assembly of a genetically-structured deterministic chemical kinetic simulation.

PubMed

Smeal, Steven W; Schmitt, Margaret A; Pereira, Ronnie Rodrigues; Prasad, Ashok; Fisk, John D

2017-01-01

To expand the quantitative, systems level understanding and foster the expansion of the biotechnological applications of the filamentous bacteriophage M13, we have unified the accumulated quantitative information on M13 biology into a genetically-structured, experimentally-based computational simulation of the entire phage life cycle. The deterministic chemical kinetic simulation explicitly includes the molecular details of DNA replication, mRNA transcription, protein translation and particle assembly, as well as the competing protein-protein and protein-nucleic acid interactions that control the timing and extent of phage production. The simulation reproduces the holistic behavior of M13, closely matching experimentally reported values of the intracellular levels of phage species and the timing of events in the M13 life cycle. The computational model provides a quantitative description of phage biology, highlights gaps in the present understanding of M13, and offers a framework for exploring alternative mechanisms of regulation in the context of the complete M13 life cycle. Copyright © 2016 Elsevier Inc. All rights reserved.

Eddy Fluxes and Sensitivity of the Water Cycle to Spatial Resolution in Idealized Regional Aquaplanet Model Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hagos, Samson M.; Leung, Lai-Yung R.; Gustafson, William I.

2014-02-28

A multi-scale moisture budget analysis is used to identify the mechanisms responsible for the sensitivity of the water cycle to spatial resolution using idealized regional aquaplanet simulations. In the higher resolution simulations, moisture transport by eddies fluxes dry the boundary layer enhancing evaporation and precipitation. This effect of eddies, which is underestimated by the physics parameterizations in the low-resolution simulations, is found to be responsible for the sensitivity of the water cycle both directly, and through its upscale effect, on the mean circulation. Correlations among moisture transport by eddies at adjacent ranges of scales provides the potential for reducing thismore » sensitivity by representing the unresolved eddies by their marginally resolved counterparts.« less

A class of finite-time dual neural networks for solving quadratic programming problems and its k-winners-take-all application.

PubMed

Li, Shuai; Li, Yangming; Wang, Zheng

2013-03-01

This paper presents a class of recurrent neural networks to solve quadratic programming problems. Different from most existing recurrent neural networks for solving quadratic programming problems, the proposed neural network model converges in finite time and the activation function is not required to be a hard-limiting function for finite convergence time. The stability, finite-time convergence property and the optimality of the proposed neural network for solving the original quadratic programming problem are proven in theory. Extensive simulations are performed to evaluate the performance of the neural network with different parameters. In addition, the proposed neural network is applied to solving the k-winner-take-all (k-WTA) problem. Both theoretical analysis and numerical simulations validate the effectiveness of our method for solving the k-WTA problem. Copyright © 2012 Elsevier Ltd. All rights reserved.

Numerical modeling of aquifer thermal energy storage

NASA Astrophysics Data System (ADS)

Tsang, C. F.; Doughty, C.; Kincaid, C. T.

1982-12-01

During 1981 and 1982, Auburn University has been performing a three cycle ATES field experiment in Mobile County, Alabama. Details of the experiment are described elsewhere in this volume. Concurrent with the first two cycles (59 C and 82 C), Lawrence Berkeley Laboratory (LBL) did numerical simulations based on field operating conditions to predict the outcome of each cycle before its conclusion. Prior to the third cycle, a series of numerical simulations were made to aid in the design of an experiment that would yield the highest recovery factor possible.

An Integrated Fuel Depletion Calculator for Fuel Cycle Options Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schneider, Erich; Scopatz, Anthony

2016-04-25

Bright-lite is a reactor modeling software developed at the University of Texas Austin to expand upon the work done with the Bright [1] reactor modeling software. Originally, bright-lite was designed to function as a standalone reactor modeling software. However, this aim was refocused t couple bright-lite with the Cyclus fuel cycle simulator [2] to make it a module for the fuel cycle simulator.

Effect of brushing and thermocycling on the shade and surface roughness of CAD-CAM ceramic restorations.

PubMed

Yuan, Judy Chia-Chun; Barão, Valentim Adelino Ricardo; Wee, Alvin G; Alfaro, Maria F; Afshari, Fatemeh S; Sukotjo, Cortino

2017-09-29

The effects of toothbrushing (B) and thermocycling (TC) on the surface texture of different materials with various fabrication processes have been investigated. However, studies of computer-aided design and computer-aided manufacturing (CAD-CAM) ceramic restorations are limited. The purpose of this in vitro study was to evaluate the effect of B and TC on the color stability and surface roughness of extrinsically characterized and glazed CAD-CAM ceramic restorations. Lithium disilicate CAD ceramic (n=90) and zirconia ceramic (n=90) were studied. All specimens were crystallized/sintered, characterized, and glazed following the manufacturer's recommendation. The specimens were divided into 9 different groups: B, TC, and a combination of B plus TC (B+TC). Brushing was performed at 50 000, 100 000, and 150 000 cycles, simulating an oral environment of 5, 10, and 15 years. Thermocycling was performed at 6000, 12 000, and 18 000 cycles, simulating an oral environment of 5, 10, and 15 years. Brushing plus TC was performed with the combination of the 50 000 cycles of B, then 6000 cycles of TC, and 10 000 cycles of B, then 12 000 cycles of TC, and 15 000 cycles of B, then 18 000 cycles of TC. The color and surface roughness of each specimen were measured before and after all interventions with simulated cycles. Color differences (ΔE) and surface roughness (ΔR a ) data were analyzed using 2-way ANOVA, followed by the least significant difference test (α=.05). The correlation between ΔE and ΔR a was statistically analyzed using the Pearson correlation analysis. Within the lithium disilicate CAD groups, intervention did not result in any significant differences in color change (P>.05). Within the zirconia groups, a 15-year clinical simulation revealed significantly higher ΔE values than a simulated 5-year exposure (P=.017). Increased simulated cycles showed significantly higher R a values for all groups. Within the zirconia groups, B revealed significantly smoother surfaces than TC (P<.001) and B+TC interventions (P<.001). For the zirconia, simulating B+TC for15 years revealed significantly higher R a values than the groups of B+TC for 5 years (P<.001) and B+TC for 10 years (P=.003). No correlation (lithium disilicate CAD, r=.079; P=.462; zirconia, r=.001; P=.989) was found between the color change and surface roughness. For both lithium disilicate CAD and zirconia, color changes were below the selected clinical perceptible threshold (ΔE=2.6) after all intervention and simulated cycles. All mean surface roughness measurements were below 0.2 μm. Generally, the surface of both lithium disilicate CAD and zirconia became rougher. No correlation was found between color difference and surface roughness for either material. Published by Elsevier Inc.

Detecting independent and recurrent copy number aberrations using interval graphs.

PubMed

Wu, Hsin-Ta; Hajirasouliha, Iman; Raphael, Benjamin J

2014-06-15

Somatic copy number aberrations SCNAS: are frequent in cancer genomes, but many of these are random, passenger events. A common strategy to distinguish functional aberrations from passengers is to identify those aberrations that are recurrent across multiple samples. However, the extensive variability in the length and position of SCNA: s makes the problem of identifying recurrent aberrations notoriously difficult. We introduce a combinatorial approach to the problem of identifying independent and recurrent SCNA: s, focusing on the key challenging of separating the overlaps in aberrations across individuals into independent events. We derive independent and recurrent SCNA: s as maximal cliques in an interval graph constructed from overlaps between aberrations. We efficiently enumerate all such cliques, and derive a dynamic programming algorithm to find an optimal selection of non-overlapping cliques, resulting in a very fast algorithm, which we call RAIG (Recurrent Aberrations from Interval Graphs). We show that RAIG outperforms other methods on simulated data and also performs well on data from three cancer types from The Cancer Genome Atlas (TCGA). In contrast to existing approaches that employ various heuristics to select independent aberrations, RAIG optimizes a well-defined objective function. We show that this allows RAIG to identify rare aberrations that are likely functional, but are obscured by overlaps with larger passenger aberrations. http://compbio.cs.brown.edu/software. © The Author 2014. Published by Oxford University Press.

Recurrence predictive models for patients with hepatocellular carcinoma after radiofrequency ablation using support vector machines with feature selection methods.

PubMed

Liang, Ja-Der; Ping, Xiao-Ou; Tseng, Yi-Ju; Huang, Guan-Tarn; Lai, Feipei; Yang, Pei-Ming

2014-12-01

Recurrence of hepatocellular carcinoma (HCC) is an important issue despite effective treatments with tumor eradication. Identification of patients who are at high risk for recurrence may provide more efficacious screening and detection of tumor recurrence. The aim of this study was to develop recurrence predictive models for HCC patients who received radiofrequency ablation (RFA) treatment. From January 2007 to December 2009, 83 newly diagnosed HCC patients receiving RFA as their first treatment were enrolled. Five feature selection methods including genetic algorithm (GA), simulated annealing (SA) algorithm, random forests (RF) and hybrid methods (GA+RF and SA+RF) were utilized for selecting an important subset of features from a total of 16 clinical features. These feature selection methods were combined with support vector machine (SVM) for developing predictive models with better performance. Five-fold cross-validation was used to train and test SVM models. The developed SVM-based predictive models with hybrid feature selection methods and 5-fold cross-validation had averages of the sensitivity, specificity, accuracy, positive predictive value, negative predictive value, and area under the ROC curve as 67%, 86%, 82%, 69%, 90%, and 0.69, respectively. The SVM derived predictive model can provide suggestive high-risk recurrent patients, who should be closely followed up after complete RFA treatment. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Estimating the effect of a rare time-dependent treatment on the recurrent event rate.

PubMed

Smith, Abigail R; Zhu, Danting; Goodrich, Nathan P; Merion, Robert M; Schaubel, Douglas E

2018-05-30

In many observational studies, the objective is to estimate the effect of treatment or state-change on the recurrent event rate. If treatment is assigned after the start of follow-up, traditional methods (eg, adjustment for baseline-only covariates or fully conditional adjustment for time-dependent covariates) may give biased results. We propose a two-stage modeling approach using the method of sequential stratification to accurately estimate the effect of a time-dependent treatment on the recurrent event rate. At the first stage, we estimate the pretreatment recurrent event trajectory using a proportional rates model censored at the time of treatment. Prognostic scores are estimated from the linear predictor of this model and used to match treated patients to as yet untreated controls based on prognostic score at the time of treatment for the index patient. The final model is stratified on matched sets and compares the posttreatment recurrent event rate to the recurrent event rate of the matched controls. We demonstrate through simulation that bias due to dependent censoring is negligible, provided the treatment frequency is low, and we investigate a threshold at which correction for dependent censoring is needed. The method is applied to liver transplant (LT), where we estimate the effect of development of post-LT End Stage Renal Disease (ESRD) on rate of days hospitalized. Copyright © 2018 John Wiley & Sons, Ltd.

Numerical simulation of two consecutive nasal respiratory cycles: toward a better understanding of nasal physiology.

PubMed

de Gabory, Ludovic; Reville, Nicolas; Baux, Yannick; Boisson, Nicolas; Bordenave, Laurence

2018-01-16

Computational fluid dynamic (CFD) simulations have greatly improved the understanding of nasal physiology. We postulate that simulating the entire and repeated respiratory nasal cycles, within the whole sinonasal cavities, is mandatory to gather more accurate observations and better understand airflow patterns. A 3-dimensional (3D) sinonasal model was constructed from a healthy adult computed tomography (CT) scan which discretized in 6.6 million cells (mean volume, 0.008 mm 3 ). CFD simulations were performed with ANSYS©FluentTMv16.0.0 software with transient and turbulent airflow (k-ω model). Two respiratory cycles (8 seconds) were simulated to assess pressure, velocity, wall shear stress, and particle residence time. The pressure gradients within the sinus cavities varied according to their place of connection to the main passage. Alternations in pressure gradients induced a slight pumping phenomenon close to the ostia but no movement of air was observed within the sinus cavities. Strong movements were observed within the inferior meatus during expiration contrary to the inspiration, as in the olfactory cleft at the same time. Particle residence time was longer during expiration than inspiration due to nasal valve resistance, as if the expiratory phase was preparing the next inspiratory phase. Throughout expiration, some particles remained in contact with the lower turbinates. The posterior part of the olfactory cleft was gradually filled with particles that did not leave the nose at the next respiratory cycle. This pattern increased as the respiratory cycle was repeated. CFD is more efficient and reliable when the entire respiratory cycle is simulated and repeated to avoid losing information. © 2018 ARS-AAOA, LLC.

Simulating carbon flows in Amazonian rainforests: how intensive C-cycle data can help to reduce vegetation model uncertainty

NASA Astrophysics Data System (ADS)

Galbraith, D.; Levine, N. M.; Christoffersen, B. O.; Imbuzeiro, H. A.; Powell, T.; Costa, M. H.; Saleska, S. R.; Moorcroft, P. R.; Malhi, Y.

2014-12-01

The mathematical codes embedded within different vegetation models ultimately represent alternative hypotheses of biosphere functioning. While formulations for some processes (e.g. leaf-level photosynthesis) are often shared across vegetation models, other processes (e.g. carbon allocation) are much more variable in their representation across models. This creates the opportunity for equifinality - models can simulate similar values of key metrics such as NPP or biomass through very different underlying causal pathways. Intensive carbon cycle measurements allow for quantification of a comprehensive suite of carbon fluxes such as the productivity and respiration of leaves, roots and wood, allowing for in-depth assessment of carbon flows within ecosystems. Thus, they provide important information on poorly-constrained C-cycle processes such as allocation. We conducted an in-depth evaluation of the ability of four commonly used dynamic global vegetation models (CLM, ED2, IBIS, JULES) to simulate carbon cycle processes at ten lowland Amazonian rainforest sites where individual C-cycle components have been measured. The rigorous model-data comparison procedure allowed identification of biases which were specific to different models, providing clear avenues for model improvement and allowing determination of internal C-cycling pathways that were better supported by data. Furthermore, the intensive C-cycle data allowed for explicit testing of the validity of a number of assumptions made by specific models in the simulation of carbon allocation and plant respiration. For example, the ED2 model assumes that maintenance respiration of stems is negligible while JULES assumes equivalent allocation of NPP to fine roots and leaves. We argue that field studies focusing on simultaneous measurement of a large number of component fluxes are fundamentally important for reducing uncertainty in vegetation model simulations.

Three Dimensional Numerical Simulation of Rocket-based Combined-cycle Engine Response During Mode Transition Events

NASA Technical Reports Server (NTRS)

Edwards, Jack R.; McRae, D. Scott; Bond, Ryan B.; Steffan, Christopher (Technical Monitor)

2003-01-01

The GTX program at NASA Glenn Research Center is designed to develop a launch vehicle concept based on rocket-based combined-cycle (RBCC) propulsion. Experimental testing, cycle analysis, and computational fluid dynamics modeling have all demonstrated the viability of the GTX concept, yet significant technical issues and challenges still remain. Our research effort develops a unique capability for dynamic CFD simulation of complete high-speed propulsion devices and focuses this technology toward analysis of the GTX response during critical mode transition events. Our principal attention is focused on Mode 1/Mode 2 operation, in which initial rocket propulsion is transitioned into thermal-throat ramjet propulsion. A critical element of the GTX concept is the use of an Independent Ramjet Stream (IRS) cycle to provide propulsion at Mach numbers less than 3. In the IRS cycle, rocket thrust is initially used for primary power, and the hot rocket plume is used as a flame-holding mechanism for hydrogen fuel injected into the secondary air stream. A critical aspect is the establishment of a thermal throat in the secondary stream through the combination of area reduction effects and combustion-induced heat release. This is a necessity to enable the power-down of the rocket and the eventual shift to ramjet mode. Our focus in this first year of the grant has been in three areas, each progressing directly toward the key initial goal of simulating thermal throat formation during the IRS cycle: CFD algorithm development; simulation of Mode 1 experiments conducted at Glenn's Rig 1 facility; and IRS cycle simulations. The remainder of this report discusses each of these efforts in detail and presents a plan of work for the next year.

Simulation and statistical analysis for the optimization of nitrogen liquefaction plant with cryogenic Claude cycle using process modeling tool: ASPEN HYSYS

NASA Astrophysics Data System (ADS)

Joshi, D. M.

2017-09-01

Cryogenic technology is used for liquefaction of many gases and it has several applications in food process engineering. Temperatures below 123 K are considered to be in the field of cryogenics. Extreme low temperatures are a basic need for many industrial processes and have several applications, such as superconductivity of magnets, space, medicine and gas industries. Several methods can be used to obtain the low temperatures required for liquefaction of gases. The process of cooling or refrigerating a gas to a temperature below its critical temperature so that liquid can be formed at some suitable pressure, which is below the critical pressure, is the basic liquefaction process. Different cryogenic cycle configurations are designed for getting the liquefied form of gases at different temperatures. Each of the cryogenic cycles like Linde cycle, Claude cycle, Kapitza cycle or modified Claude cycle has its own advantages and disadvantages. The placement of heat exchangers, Joule-Thompson valve and turboexpander decides the configuration of a cryogenic cycle. Each configuration has its own efficiency according to the application. Here, a nitrogen liquefaction plant is used for the analysis purpose. The process modeling tool ASPEN HYSYS can provide a software simulation approach before the actual implementation of the plant in the field. This paper presents the simulation and statistical analysis of the Claude cycle with the process modeling tool ASPEN HYSYS. It covers the technique used to optimize the liquefaction of the plant. The simulation results so obtained can be used as a reference for the design and optimization of the nitrogen liquefaction plant. Efficient liquefaction will give the best performance and productivity to the plant.

Aberrant AR Signaling as a Function of Declining Androgen

DTIC Science & Technology

2006-08-01

Prescott J, Henderson M, Tilley WD, Coetzee GA. GRIP1 mediates the interaction between the amino- and carboxyl-termini of the androgen receptor. Biol...involve AR occupancy of the PSA locus. Can. Res. 65:8003-8008, 2005. Prescott , J. Coetzee, GA: Molecular Chaperones throughout the life cycle of...for Microbiology . All Rights Reserved. Locus-Wide Chromatin Remodeling and Enhanced Androgen Receptor-Mediated Transcription in Recurrent Prostate

Complete Resolution of a Recurrent Canine Anal Sac Squamous Cell Carcinoma with Palliative Radiotherapy and Carboplatin Chemotherapy

PubMed Central

Giuliano, Antonio; Dobson, Jane; Mason, Sarah

2017-01-01

Anal sac squamous cell carcinoma (SCC) is a rare tumor in dogs. Only eight cases have been described in the literature, and previous reports of treatment only describe surgery or palliative treatment with non-steroidal anti-inflammatory drugs. We report a case of a 12-year-old female neutered Labrador with locally advanced anal sac SCC. The dog was treated with four cycles of carboplatin 300 mg/m2 and four weekly fractions of 8.5 Gy radiation. The dog achieved a complete response, and one year later the dog is still alive and well with no evidence of tumor recurrence. Radiotherapy in combination with carboplatin chemotherapy was effective in the long-term control of this rare disease. PMID:29056703

Phase I trial of p28 (NSC745104), a non-HDM2-mediated peptide inhibitor of p53 ubiquitination in pediatric patients with recurrent or progressive central nervous system tumors: A Pediatric Brain Tumor Consortium Study.

PubMed

Lulla, Rishi R; Goldman, Stewart; Yamada, Tohru; Beattie, Craig W; Bressler, Linda; Pacini, Michael; Pollack, Ian F; Fisher, Paul Graham; Packer, Roger J; Dunkel, Ira J; Dhall, Girish; Wu, Shengjie; Onar, Arzu; Boyett, James M; Fouladi, Maryam

2016-09-01

p53 is a promising target in human cancer. p28 is a cell-penetrating peptide that preferentially enters cancer cells and binds to both wild-type and mutant p53 protein, inhibiting COP1-mediated ubiquitination and proteasomal degradation. This results in increased levels of p53, which induces cell cycle arrest at G2/M. We conducted a phase I study to determine the maximum-tolerated dose (MTD) and describe the dose-limiting toxicities (DLTs) and pharmacokinetics (PKs) of p28 in children. Children aged 3-21 years with recurrent or progressive central nervous system tumors were eligible. Intravenous p28 was administered 3 times weekly for 4 consecutive weeks of a 6-week cycle at 4.16 mg/kg/dose (the adult recommended phase II dose) using a rolling-6 study design. Expression status of p53 was characterized by immunohistochemistry, and serum PK parameters were established on the second dose. Of the 18 eligible patients enrolled in the study, 12 completed the DLT monitoring period and were evaluable for toxicity. p28 was well-tolerated; 7 participants received ≥2 courses, and the most common adverse event attributed to the drug was transient grade 1 infusion-related reaction. PK analysis revealed a profile similar to adults; however, an increased area under the curve was observed in pediatric patients. High p53 expression in tumor cell nuclei was observed in 6 of 12 available tissue samples. There were no objective responses; 2 participants remained stable on the study for >4 cycles. This phase I study demonstrated that p28 is well-tolerated in children with recurrent CNS malignancies at the adult recommended phase II dose. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Weekly Docetaxel, Cisplatin, and Cetuximab in Palliative Treatment of Patients with Squamous Cell Carcinoma of the Head and Neck.

PubMed

Trieu, Vanessa; Pinto, Harlan; Riess, Jonathan W; Lira, Ruth; Luciano, Richard; Coty, Jessie; Boothroyd, Derek; Colevas, A Dimitrios

2018-03-14

Chemotherapy for recurrent, metastatic squamous cell carcinoma of the head and neck need not be known for extreme toxicity.The weekly regimen studied here has been demonstrated to be tolerable and effective. The objective of this study was to establish the response rate, progression-free survival (PFS) and overall survival (OS), and safety profile of weekly docetaxel, platinum, and cetuximab (TPC) in patients with relapsed or metastatic squamous cell carcinoma of the head and neck (SCCHN). Twenty-nine patients with metastatic or recurrent SCCHN with an Eastern Cooperative Oncology Group (ECOG) performance status <3 were enrolled in an institutional review board-approved phase II trial. This study permitted prior chemoradiation, radiation, and/or surgery, provided that 3 months had elapsed since the end of the potentially curative treatment. Patients received cisplatin 30 mg/m 2 or carboplatin area under the curve (AUC) 2, docetaxel 30 mg/m 2 , and cetuximab 250 mg/m 2 weekly for 3 weeks, followed by a break during the fourth week, for a 28-day cycle. Planned intrapatient dose modifications were based on individual toxicity. Twenty-seven patients received TPC and were evaluable for response and toxicity. Rates of complete response (CR), partial response (PR), and confirmed PR were 3%, 52%, and 30%, respectively. The overall objective response rate was 56%. Estimated median PFS and OS were 4.8 and 14.7 months, respectively. The rates of grade 3 and 4 worst-grade adverse events (AEs) per patient were 85% and 7%, respectively. Dose density through cycle 4 was preserved for all patients; however, treatment beyond cycle 6 with the TPC regimen proved unfeasible. Weekly docetaxel, cisplatin, and cetuximab is an effective regimen for patients with metastatic or recurrent SCCHN. Response rates, PFS, and OS compare favorably with other combination chemotherapy treatments. Grade 4 toxicity rates observed in this study were substantially lower than those described with regimens using less frequent, higher-dose chemotherapy schedules. © AlphaMed Press; the data published online to support this summary is the property of the authors.

Evolution of Our Understanding of the Solar Dynamo During Solar Cycle 24

NASA Astrophysics Data System (ADS)

Munoz-Jaramillo, A.

2017-12-01

Solar cycle 24 has been an exciting cycle for our understanding of the solar dynamo: 1. It was the first cycle for which dynamo based predictions were ever used teaching us valuable lessons. 2. It has given us the opportunity to observe a deep minimum and a weak cycle with a high level of of observational detail . 3. It is full of breaktrhoughs in anelastic MHD dynamo simulations (regular cycles, buoyant flux-tubes, mounder-like events). 4. It has seen the creation of bridges between the kinematic flux-transport and anelastic MHD approaches. 5. It has ushered a new generation of realistic surface flux-transport simulations 6. We have achieved significant observational progress in our understanding of solar cycle propagation. The objective of this talk is to highlight some of the most important results, giving special emphasis on what they have taught us about solar cycle predictability.

Efficiency Enhancement of Chiller and Heat Pump Using Natural Working Fluids with Two-phase Flow Ejector

NASA Astrophysics Data System (ADS)

Yoshikawa, Choiku; Hattori, Kazuhiro; Jeong, Jongsoo; Saito, Kiyoshi; Kawai, Sunao

An ejector can transform the expansion energy of the driving flow into the pressure build-up energy of the suction flow. Therefore, by utilizing the ejector instead of the expansion valve for the vapor compression cycle, the performance of the cycle can be greatly improved. Until now, the performance of the vapor compression cycle with the ejector has not been examined sufficiently. Therefore, this paper constructs the simulation model of the vapor compression cycle with the ejector and investigates the performance of that cycle by the simulation. Working fluids are ammonia and CO2. As a result, in case of the ejector efficiency 90%, COP of the vapor compression cycle using ammonia with the ejector is 5% higher than that of the conventional cycle and COP using CO2 with the ejector is 22% higher than that of the conventional cycle.

Application of dynamic recurrent neural networks in nonlinear system identification

NASA Astrophysics Data System (ADS)

Du, Yun; Wu, Xueli; Sun, Huiqin; Zhang, Suying; Tian, Qiang

2006-11-01

An adaptive identification method of simple dynamic recurrent neural network (SRNN) for nonlinear dynamic systems is presented in this paper. This method based on the theory that by using the inner-states feed-back of dynamic network to describe the nonlinear kinetic characteristics of system can reflect the dynamic characteristics more directly, deduces the recursive prediction error (RPE) learning algorithm of SRNN, and improves the algorithm by studying topological structure on recursion layer without the weight values. The simulation results indicate that this kind of neural network can be used in real-time control, due to its less weight values, simpler learning algorithm, higher identification speed, and higher precision of model. It solves the problems of intricate in training algorithm and slow rate in convergence caused by the complicate topological structure in usual dynamic recurrent neural network.

Self-Consistent Scheme for Spike-Train Power Spectra in Heterogeneous Sparse Networks.

PubMed

Pena, Rodrigo F O; Vellmer, Sebastian; Bernardi, Davide; Roque, Antonio C; Lindner, Benjamin

2018-01-01

Recurrent networks of spiking neurons can be in an asynchronous state characterized by low or absent cross-correlations and spike statistics which resemble those of cortical neurons. Although spatial correlations are negligible in this state, neurons can show pronounced temporal correlations in their spike trains that can be quantified by the autocorrelation function or the spike-train power spectrum. Depending on cellular and network parameters, correlations display diverse patterns (ranging from simple refractory-period effects and stochastic oscillations to slow fluctuations) and it is generally not well-understood how these dependencies come about. Previous work has explored how the single-cell correlations in a homogeneous network (excitatory and inhibitory integrate-and-fire neurons with nearly balanced mean recurrent input) can be determined numerically from an iterative single-neuron simulation. Such a scheme is based on the fact that every neuron is driven by the network noise (i.e., the input currents from all its presynaptic partners) but also contributes to the network noise, leading to a self-consistency condition for the input and output spectra. Here we first extend this scheme to homogeneous networks with strong recurrent inhibition and a synaptic filter, in which instabilities of the previous scheme are avoided by an averaging procedure. We then extend the scheme to heterogeneous networks in which (i) different neural subpopulations (e.g., excitatory and inhibitory neurons) have different cellular or connectivity parameters; (ii) the number and strength of the input connections are random (Erdős-Rényi topology) and thus different among neurons. In all heterogeneous cases, neurons are lumped in different classes each of which is represented by a single neuron in the iterative scheme; in addition, we make a Gaussian approximation of the input current to the neuron. These approximations seem to be justified over a broad range of parameters as indicated by comparison with simulation results of large recurrent networks. Our method can help to elucidate how network heterogeneity shapes the asynchronous state in recurrent neural networks.

Real-time parallel processing of grammatical structure in the fronto-striatal system: a recurrent network simulation study using reservoir computing.

PubMed

Hinaut, Xavier; Dominey, Peter Ford

2013-01-01

Sentence processing takes place in real-time. Previous words in the sentence can influence the processing of the current word in the timescale of hundreds of milliseconds. Recent neurophysiological studies in humans suggest that the fronto-striatal system (frontal cortex, and striatum--the major input locus of the basal ganglia) plays a crucial role in this process. The current research provides a possible explanation of how certain aspects of this real-time processing can occur, based on the dynamics of recurrent cortical networks, and plasticity in the cortico-striatal system. We simulate prefrontal area BA47 as a recurrent network that receives on-line input about word categories during sentence processing, with plastic connections between cortex and striatum. We exploit the homology between the cortico-striatal system and reservoir computing, where recurrent frontal cortical networks are the reservoir, and plastic cortico-striatal synapses are the readout. The system is trained on sentence-meaning pairs, where meaning is coded as activation in the striatum corresponding to the roles that different nouns and verbs play in the sentences. The model learns an extended set of grammatical constructions, and demonstrates the ability to generalize to novel constructions. It demonstrates how early in the sentence, a parallel set of predictions are made concerning the meaning, which are then confirmed or updated as the processing of the input sentence proceeds. It demonstrates how on-line responses to words are influenced by previous words in the sentence, and by previous sentences in the discourse, providing new insight into the neurophysiology of the P600 ERP scalp response to grammatical complexity. This demonstrates that a recurrent neural network can decode grammatical structure from sentences in real-time in order to generate a predictive representation of the meaning of the sentences. This can provide insight into the underlying mechanisms of human cortico-striatal function in sentence processing.

Real-Time Parallel Processing of Grammatical Structure in the Fronto-Striatal System: A Recurrent Network Simulation Study Using Reservoir Computing

PubMed Central

Hinaut, Xavier; Dominey, Peter Ford

2013-01-01

Sentence processing takes place in real-time. Previous words in the sentence can influence the processing of the current word in the timescale of hundreds of milliseconds. Recent neurophysiological studies in humans suggest that the fronto-striatal system (frontal cortex, and striatum – the major input locus of the basal ganglia) plays a crucial role in this process. The current research provides a possible explanation of how certain aspects of this real-time processing can occur, based on the dynamics of recurrent cortical networks, and plasticity in the cortico-striatal system. We simulate prefrontal area BA47 as a recurrent network that receives on-line input about word categories during sentence processing, with plastic connections between cortex and striatum. We exploit the homology between the cortico-striatal system and reservoir computing, where recurrent frontal cortical networks are the reservoir, and plastic cortico-striatal synapses are the readout. The system is trained on sentence-meaning pairs, where meaning is coded as activation in the striatum corresponding to the roles that different nouns and verbs play in the sentences. The model learns an extended set of grammatical constructions, and demonstrates the ability to generalize to novel constructions. It demonstrates how early in the sentence, a parallel set of predictions are made concerning the meaning, which are then confirmed or updated as the processing of the input sentence proceeds. It demonstrates how on-line responses to words are influenced by previous words in the sentence, and by previous sentences in the discourse, providing new insight into the neurophysiology of the P600 ERP scalp response to grammatical complexity. This demonstrates that a recurrent neural network can decode grammatical structure from sentences in real-time in order to generate a predictive representation of the meaning of the sentences. This can provide insight into the underlying mechanisms of human cortico-striatal function in sentence processing. PMID:23383296

Simulation of the synergistic low Earth orbit effects of vacuum thermal cycling, vacuum UV radiation, and atomic oxygen

NASA Technical Reports Server (NTRS)

Dever, Joyce A.; Degroh, Kim K.; Stidham, Curtis R.; Stueber, Thomas J.; Dever, Therese M.; Rodriguez, Elvin; Terlep, Judith A.

1992-01-01

In order to assess the low Earth orbit (LEO) durability of candidate space materials, it is necessary to use ground laboratory facilities which provide LEO environmental effects. A facility combining vacuum thermal cycling and vacuum ultraviolet (VUV) radiation has been designed and constructed at NASA Lewis Research Center for this purpose. This facility can also be operated without the VUV lamps. An additional facility can be used to provide VUV exposure only. By utilizing these facilities, followed by atomic oxygen exposure in an RF plasma asher, the effects of the individual vacuum thermal cycling and VUV environments can be compared to the effect of the combined vacuum thermal cycling/VUV environment on the atomic oxygen durability of materials. The synergistic effects of simulated LEO environmental conditions on materials were evaluated by first exposing materials to vacuum thermal cycling, VUV, and vacuum thermal cycling/VUV environments followed by exposure to atomic oxygen in an RP plasma asher. Candidate space power materials such as atomic oxygen protected polyimides and solar concentrator mirrors were evaluated using these facilities. Characteristics of the Vacuum Thermal Cycling/VUV Exposure Facility which simulates the temperature sequences and solar ultraviolet radiation exposure that would be experienced by a spacecraft surface in LEO are discussed. Results of durability evaluations of some candidate space power materials to the simulated LEO environmental conditions will also be discussed. Such results have indicated that for some materials, atomic oxygen durability is affected by previous exposure to thermal cycling and/or VUV exposure.

Wet cooling towers: rule-of-thumb design and simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leeper, Stephen A.

1981-07-01

A survey of wet cooling tower literature was performed to develop a simplified method of cooling tower design and simulation for use in power plant cycle optimization. The theory of heat exchange in wet cooling towers is briefly summarized. The Merkel equation (the fundamental equation of heat transfer in wet cooling towers) is presented and discussed. The cooling tower fill constant (Ka) is defined and values derived. A rule-of-thumb method for the optimized design of cooling towers is presented. The rule-of-thumb design method provides information useful in power plant cycle optimization, including tower dimensions, water consumption rate, exit air temperature,more » power requirements and construction cost. In addition, a method for simulation of cooling tower performance at various operating conditions is presented. This information is also useful in power plant cycle evaluation. Using the information presented, it will be possible to incorporate wet cooling tower design and simulation into a procedure to evaluate and optimize power plant cycles.« less

Characterizing Observed Limit Cycles in the Cassini Main Engine Guidance Control System

NASA Technical Reports Server (NTRS)

Rizvi, Farheen; Weitl, Raquel M.

2011-01-01

The Cassini spacecraft dynamics-related telemetry during long Main Engine (ME) burns has indicated the presence of stable limit cycles between 0.03-0.04 Hz frequencies. These stable limit cycles cause the spacecraft to possess non-zero oscillating rates for extended periods of time. This indicates that the linear ME guidance control system does not model the complete dynamics of the spacecraft. In this study, we propose that the observed limit cycles in the spacecraft dynamics telemetry appear from a stable interaction between the unmodeled nonlinear elements in the ME guidance control system. Many nonlinearities in the control system emerge from translating the linear engine gimbal actuator (EGA) motion into a spacecraft rotation. One such nonlinearity comes from the gear backlash in the EGA system, which is the focus of this paper. The limit cycle characteristics and behavior can be predicted by modeling this gear backlash nonlinear element via a describing function and studying the interaction of this describing function with the overall dynamics of the spacecraft. The linear ME guidance controller and gear backlash nonlinearity are modeled analytically. The frequency, magnitude, and nature of the limit cycle are obtained from the frequency response of the ME guidance controller and nonlinear element. In addition, the ME guidance controller along with the nonlinearity is simulated. The simulation response contains a limit cycle with similar characterstics as predicted analytically: 0.03-0.04 Hz frequency and stable, sustained oscillations. The analytical and simulated limit cycle responses are compared to the flight telemetry for long burns such as the Saturn Orbit Insertion and Main Engine Orbit Trim Maneuvers. The analytical and simulated limit cycle characteristics compare well with the actual observed limit cycles in the flight telemetry. Both have frequencies between 0.03-0.04 Hz and stable oscillations. This work shows that the stable limit cycles occur due to the interaction between the unmodeled nonlinear elements and linear ME guidance controller.

The effect of 'running-in' on the tribology and surface morphology of metal-on-metal Birmingham hip resurfacing device in simulator studies.

PubMed

Vassiliou, K; Elfick, A P D; Scholes, S C; Unsworth, A

2006-02-01

It is well documented that hard bearing combinations show a running-in phenomenon in vitro and there is also some evidence of this from retrieval studies. In order to investigate this phenomenon, five Birmingham hip resurfacing devices were tested in a hip wear simulator. One of these (joint 1) was also tested in a friction simulator before, during, and after the wear test and surface analysis was conducted throughout portions of the testing. The wear showed the classical running in with the wear rate falling from 1.84 mm3 per 10(6) cycles for the first 10(6) cycles of testing to 0.24 mm3 per 10(6) cycles over the final 2 x 10(6) cycles of testing. The friction tests suggested boundary lubrication initially, but at 1 x 10(6) cycles a mixed lubrication regime was evident. By 2 x 10(6) cycles the classical Stribeck curve had formed, indicating a considerable contribution from the fluid film at higher viscosities. This continued to be evident at both 3 x 10(6) and 5 x 10(6) cycles. The surface study complements these findings.

Computational tool for simulation of power and refrigeration cycles

NASA Astrophysics Data System (ADS)

Córdoba Tuta, E.; Reyes Orozco, M.

2016-07-01

Small improvement in thermal efficiency of power cycles brings huge cost savings in the production of electricity, for that reason have a tool for simulation of power cycles allows modeling the optimal changes for a best performance. There is also a big boom in research Organic Rankine Cycle (ORC), which aims to get electricity at low power through cogeneration, in which the working fluid is usually a refrigerant. A tool to design the elements of an ORC cycle and the selection of the working fluid would be helpful, because sources of heat from cogeneration are very different and in each case would be a custom design. In this work the development of a multiplatform software for the simulation of power cycles and refrigeration, which was implemented in the C ++ language and includes a graphical interface which was developed using multiplatform environment Qt and runs on operating systems Windows and Linux. The tool allows the design of custom power cycles, selection the type of fluid (thermodynamic properties are calculated through CoolProp library), calculate the plant efficiency, identify the fractions of flow in each branch and finally generates a report very educational in pdf format via the LaTeX tool.

Architecture and inherent robustness of a bacterial cell-cycle control system.

PubMed

Shen, Xiling; Collier, Justine; Dill, David; Shapiro, Lucy; Horowitz, Mark; McAdams, Harley H

2008-08-12

A closed-loop control system drives progression of the coupled stalked and swarmer cell cycles of the bacterium Caulobacter crescentus in a near-mechanical step-like fashion. The cell-cycle control has a cyclical genetic circuit composed of four regulatory proteins with tight coupling to processive chromosome replication and cell division subsystems. We report a hybrid simulation of the coupled cell-cycle control system, including asymmetric cell division and responses to external starvation signals, that replicates mRNA and protein concentration patterns and is consistent with observed mutant phenotypes. An asynchronous sequential digital circuit model equivalent to the validated simulation model was created. Formal model-checking analysis of the digital circuit showed that the cell-cycle control is robust to intrinsic stochastic variations in reaction rates and nutrient supply, and that it reliably stops and restarts to accommodate nutrient starvation. Model checking also showed that mechanisms involving methylation-state changes in regulatory promoter regions during DNA replication increase the robustness of the cell-cycle control. The hybrid cell-cycle simulation implementation is inherently extensible and provides a promising approach for development of whole-cell behavioral models that can replicate the observed functionality of the cell and its responses to changing environmental conditions.

The effect of endometrial scratch on natural-cycle cryopreserved embryo transfer outcomes: a randomized controlled study.

PubMed

Mak, Jennifer Sze Man; Chung, Cathy Hoi Sze; Chung, Jacqueline Pui Wah; Kong, Grace Wing Shan; Saravelos, Sotirios H; Cheung, Lai Ping; Li, Tin-Chiu

2017-07-01

The benefit of endometrial scratch (ES) prior to embryo transfer is controversial. Systemic analysis has confirmed its potential benefit, especially in women with repeated IVF failures, yet most studies have focused on fresh embryo transfer, and its effect on vitrified-warmed embryo transfer (FET) cycles is yet to be explored. We hereby present our prospective, double-blind, randomized controlled study on the evaluation of the implantation and pregnancy rate after ES prior to natural-cycle FET. A total of 299 patients underwent natural-cycle FET and were randomized to receive ES (n = 115) or endocervical manipulation as control (n = 114) prior to FET cycle, and a total of 196 patients had embryo transfer (93 patients in each group). Our study showed no significant difference in the implantation and pregnancy rate, as well as the clinical and ongoing pregnancy or live birth rates between the two groups. It appears that ES does not have any beneficial effect on an unselected group of women undergoing FET in natural cycles. Further studies on its effect in women with recurrent implantation failure after IVF are warranted. Copyright © 2017 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Shuttle operations simulation model programmers'/users' manual

NASA Technical Reports Server (NTRS)

Porter, D. G.

1972-01-01

The prospective user of the shuttle operations simulation (SOS) model is given sufficient information to enable him to perform simulation studies of the space shuttle launch-to-launch operations cycle. The procedures used for modifying the SOS model to meet user requirements are described. The various control card sequences required to execute the SOS model are given. The report is written for users with varying computer simulation experience. A description of the components of the SOS model is included that presents both an explanation of the logic involved in the simulation of the shuttle operations cycle and a description of the routines used to support the actual simulation.

A combined power and ejector refrigeration cycle for low temperature heat sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, B.; Weng, Y.W.

A combined power and ejector refrigeration cycle for low temperature heat sources is under investigation in this paper. The proposed cycle combines the organic Rankine cycle and the ejector refrigeration cycle. The ejector is driven by the exhausts from the turbine to produce power and refrigeration simultaneously. A simulation was carried out to analyze the cycle performance using R245fa as the working fluid. A thermal efficiency of 34.1%, an effective efficiency of 18.7% and an exergy efficiency of 56.8% can be obtained at a generating temperature of 395 K, a condensing temperature of 298 K and an evaporating temperature ofmore » 280 K. Simulation results show that the proposed cycle has a big potential to produce refrigeration and most exergy losses take place in the ejector. (author)« less

Dysphagia is not a Valuable Indicator of Tumor Response after Preoperative Chemotherapy for R0 Resected Patients with Adenocarcinoma of the Gastroesophageal Junction.

PubMed

Strandby, R B; Svendsen, L B; Bæksgaard, L; Egeland, C; Achiam, M P

2016-06-01

Monitoring treatment response to preoperative chemotherapy is of utmost importance to avoid treatment toxicity, especially in non-responding patients. Currently, no reliable methods exist for tumor response assessment after preoperative chemotherapy. Therefore, the aim of this study was to evaluate dysphagia as a predictor of tumor response after preoperative chemotherapy and as a predictor of recurrence and survival. Patients with adenocarcinoma of the gastroesophageal junction, treated between 2010 and 2012, were retrospectively reviewed. Dysphagia scores (Mellow-Pinkas) were obtained before and after three cycles of perioperative chemotherapy together with clinicopathological patient characteristics. A clinical response was defined as improvement of dysphagia by at least 1 score from the baseline. The tumor response was defined as down staging of T-stage from initial computer tomography (CT) scan (cT-stage) to pathologic staging of surgical specimen (pT-stage). Patients were followed until death or censored on June 27th, 2014. Of the 110 included patients, 59.1% had improvement of dysphagia after three cycles of perioperative chemotherapy, and 31.8% had a chemotherapy-induced tumor response after radical resection of tumor. Improvement of dysphagia was not correlated with the tumor response in the multivariate analysis (p = 0.23). Moreover, the presence of dysphagia was not correlated with recurrence (p = 0.92) or survival (p = 0.94) in the multivariate analysis. In our study, improvement of dysphagia was not valid for tumor response evaluation after preoperative chemotherapy and was not correlated with the tumor response. The presence of dysphagia does not seem to be a predictor of recurrence or survival. © The Finnish Surgical Society 2015.

An Audit of the Use of Gonadorelin Analogues to Prevent Recurrent Acute Symptoms in Patients with Acute Porphyria in the United Kingdom.

PubMed

Schulenburg-Brand, Danja; Gardiner, Tricia; Guppy, Simon; Rees, David C; Stein, Penelope; Barth, Julian; Felicity Stewart, M; Badminton, Michael

2017-01-01

Severe recurrent acute attacks of porphyria have traditionally been treated with either prophylactic human haemin or gonadorelin analogues (GnA) in females. Evidence on the most effective treatment for this patient subgroup is lacking. This audit surveyed the use of prophylactic GnA in the UK.Twenty female patients (who experienced between 2 and 45 acute attacks of porphyria requiring hospitalisation and treatment with human haemin prior to GnA prophylaxis) were included in the audit. Data was retrospectively collected based on patient history and case review.Twenty three treatment courses were given lasting a median period of 12 months. Monthly subcutaneous Goserelin was most commonly used. In three patients in whom timing with the menstrual cycle was not considered, an acute attack occurred after initiation of the first dose. The majority of patients experienced oestrogen deficiency symptoms during treatment. Fifty percent of the prescribed courses of GnA resulted in a degree of clinical benefit. This successfully treated group experienced between 3 and 20 acute attacks prior to and between 0 and 6 acute attacks during GnA treatment.The audit revealed large variation in practice in the United Kingdom regarding indication, duration of treatment, specific drug used and management of side effects. In view of the limited treatment options available for this cohort and the mixed outcome successes reported, we believe it is reasonable for porphyria specialists to continue offering GnA treatment to women with severe recurrent debilitating acute attacks of porphyria associated with the menstrual cycle, and we propose best practice guidelines to standardise management.

Recurrent high anion gap metabolic acidosis secondary to 5-oxoproline (pyroglutamic acid).

PubMed

Tailor, Prayus; Raman, Tuhina; Garganta, Cheryl L; Njalsson, Runa; Carlsson, Katarina; Ristoff, Ellinor; Carey, Hugh B

2005-07-01

High anion gap metabolic acidosis in adults is a severe metabolic disorder for which the primary organic acid usually is apparent by clinical history and standard laboratory testing. We report a case of recurrent high anion gap metabolic acidosis in a 48-year-old man who initially presented with anorexia and malaise. Physical examination was unrevealing. Arterial pH was 6.98, P co 2 was 5 mm Hg, and chemistry tests showed a bicarbonate level of 3 mEq/L (3 mmol/L), anion gap of 32 mEq/L (32 mmol/L), and a negative toxicology screen result, except for an acetaminophen (paracetamol) level of 7.5 mug/mL. Metabolic acidosis resolved with administration of intravenous fluids. Subsequently, he experienced 5 more episodes of high anion gap metabolic acidosis during an 8-month span. Methanol, ethylene glycol, acetone, ethanol, d -lactate, and hippuric acid screens were negative. Lactate levels were modestly elevated, and acetaminophen levels were elevated for 5 of 6 admissions. These episodes defied explanation until 3 urinary organic acid screens, obtained on separate admissions, showed striking elevations of 5-oxoproline levels. Inborn errors of metabolism in the gamma-glutamyl cycle causing recurrent 5-oxoprolinuria and high anion gap metabolic acidosis are rare, but well described in children. Recently, there have been several reports of apparent acquired 5-oxoprolinuria and high anion gap metabolic acidosis in adults in association with acetaminophen use. Acetaminophen may, in susceptible individuals, disrupt regulation of the gamma-glutamyl cycle and result in excessive 5-oxoproline production. Suspicion for 5-oxoproline-associated high anion gap metabolic acidosis should be entertained when the cause of high anion gap metabolic acidosis remains poorly defined, the anion gap cannot be explained reasonably by measured organic acids, and there is concomitant acetaminophen use.

Solar panel thermal cycling testing by solar simulation and infrared radiation methods

NASA Technical Reports Server (NTRS)

Nuss, H. E.

1980-01-01

For the solar panels of the European Space Agency (ESA) satellites OTS/MAROTS and ECS/MARECS the thermal cycling tests were performed by using solar simulation methods. The performance data of two different solar simulators used and the thermal test results are described. The solar simulation thermal cycling tests for the ECS/MARECS solar panels were carried out with the aid of a rotatable multipanel test rig by which simultaneous testing of three solar panels was possible. As an alternative thermal test method, the capability of an infrared radiation method was studied and infrared simulation tests for the ultralight panel and the INTELSAT 5 solar panels were performed. The setup and the characteristics of the infrared radiation unit using a quartz lamp array of approx. 15 sq and LN2-cooled shutter and the thermal test results are presented. The irradiation uniformity, the solar panel temperature distribution, temperature changing rates for both test methods are compared. Results indicate the infrared simulation is an effective solar panel thermal testing method.

Effects of long memory in the order submission process on the properties of recurrence intervals of large price fluctuations

NASA Astrophysics Data System (ADS)

Meng, Hao; Ren, Fei; Gu, Gao-Feng; Xiong, Xiong; Zhang, Yong-Jie; Zhou, Wei-Xing; Zhang, Wei

2012-05-01

Understanding the statistical properties of recurrence intervals (also termed return intervals in econophysics literature) of extreme events is crucial to risk assessment and management of complex systems. The probability distributions and correlations of recurrence intervals for many systems have been extensively investigated. However, the impacts of microscopic rules of a complex system on the macroscopic properties of its recurrence intervals are less studied. In this letter, we adopt an order-driven stock model to address this issue for stock returns. We find that the distributions of the scaled recurrence intervals of simulated returns have a power-law scaling with stretched exponential cutoff and the intervals possess multifractal nature, which are consistent with empirical results. We further investigate the effects of long memory in the directions (or signs) and relative prices of the order flow on the characteristic quantities of these properties. It is found that the long memory in the order directions (Hurst index Hs) has a negligible effect on the interval distributions and the multifractal nature. In contrast, the power-law exponent of the interval distribution increases linearly with respect to the Hurst index Hx of the relative prices, and the singularity width of the multifractal nature fluctuates around a constant value when Hx<0.7 and then increases with Hx. No evident effects of Hs and Hx are found on the long memory of the recurrence intervals. Our results indicate that the nontrivial properties of the recurrence intervals of returns are mainly caused by traders' behaviors of persistently placing new orders around the best bid and ask prices.

Some new methods and results in examination of distribution of rare strongest events

NASA Astrophysics Data System (ADS)

Pisarenko, Vladilen; Rodkin, Mikhail

2016-04-01

In the study of disaster statistics the examination of the distribution tail - the range of rare strongest events - appears to be the mostly difficult and the mostly important problem. We discuss here this problem using two different approaches. In the first one we use the limit distributions of the theory of extreme values for parameterization of behavior of the distribution tail. Our method consists in estimation of the maximum size Mmax(T) (e.g. magnitude, earthquake energy, PGA value, victims or economic losses from catastrophe, etc.) that will occur in a prescribed future time interval T. In this particular case we combine the historical earthquake catalogs with instrumental ones since historical catalogs cover much longer time periods and thus can essentially improve seismic statistics in the higher magnitude domain. We apply here this technique to two historical Japan catalogs (the Usami earthquake catalog 599-1884, and the Utsu catalog, 1885-1925) and to the instrumental JMA catalog (1926-2014). We have compared the parameters of historical catalogs with ones derived from the instrumental JMA catalog and have found that the Usami catalog is incompatible with the instrumental one, whereas the Utsu catalog is statistically compatible in the higher magnitude domain with the JMA catalog. In all examined cases the effect of the "bending down" of the graph of strong earthquake recurrence was found as the typical of the seismic regime. Another method is connected with the use of the multiplicative cascade model (that in some aspects is an analogue of the ETAS model). It is known that the ordinary Gutenberg-Richter law of earthquake recurrence can be imitated within the scheme of multiplicative cascade in which the seismic regime is treated as a sequence of a large number of episodes of avalanche-like relaxation, randomly occurring on the set of metastable subsystems. This model simulates such well known regularity of the seismic regime as a decrease in b-value in connection with the strong earthquakes occurrence. If the memory of the system is taken into account the cascade model simulates the Omori law of aftershock number decay, the existence of the foreshock activity and the seismic cycle. We use here the cascade model to imitate the effect of "bending down" of the graph of strong earthquake recurrence and the possibility of occurrence of characteristic earthquakes. The results are compared with the seismicity and the physical conditions of occurrence of characteristic earthquakes are suggested. Examples of mutual interpretation of results obtained in the case of the use of theory of extreme values and of the use of the cascade model are presented.

Reconciling solar and stellar magnetic cycles with nonlinear dynamo simulations.

PubMed

Strugarek, A; Beaudoin, P; Charbonneau, P; Brun, A S; do Nascimento, J-D

2017-07-14

The magnetic fields of solar-type stars are observed to cycle over decadal periods-11 years in the case of the Sun. The fields originate in the turbulent convective layers of stars and have a complex dependency upon stellar rotation rate. We have performed a set of turbulent global simulations that exhibit magnetic cycles varying systematically with stellar rotation and luminosity. We find that the magnetic cycle period is inversely proportional to the Rossby number, which quantifies the influence of rotation on turbulent convection. The trend relies on a fundamentally nonlinear dynamo process and is compatible with the Sun's cycle and those of other solar-type stars. Copyright © 2017, American Association for the Advancement of Science.

A new neural observer for an anaerobic bioreactor.

PubMed

Belmonte-Izquierdo, R; Carlos-Hernandez, S; Sanchez, E N

2010-02-01

In this paper, a recurrent high order neural observer (RHONO) for anaerobic processes is proposed. The main objective is to estimate variables of methanogenesis: biomass, substrate and inorganic carbon in a completely stirred tank reactor (CSTR). The recurrent high order neural network (RHONN) structure is based on the hyperbolic tangent as activation function. The learning algorithm is based on an extended Kalman filter (EKF). The applicability of the proposed scheme is illustrated via simulation. A validation using real data from a lab scale process is included. Thus, this observer can be successfully implemented for control purposes.

Scenario and modelling uncertainty in global mean temperature change derived from emission driven Global Climate Models

NASA Astrophysics Data System (ADS)

Booth, B. B. B.; Bernie, D.; McNeall, D.; Hawkins, E.; Caesar, J.; Boulton, C.; Friedlingstein, P.; Sexton, D.

2012-09-01

We compare future changes in global mean temperature in response to different future scenarios which, for the first time, arise from emission driven rather than concentration driven perturbed parameter ensemble of a Global Climate Model (GCM). These new GCM simulations sample uncertainties in atmospheric feedbacks, land carbon cycle, ocean physics and aerosol sulphur cycle processes. We find broader ranges of projected temperature responses arising when considering emission rather than concentration driven simulations (with 10-90 percentile ranges of 1.7 K for the aggressive mitigation scenario up to 3.9 K for the high end business as usual scenario). A small minority of simulations resulting from combinations of strong atmospheric feedbacks and carbon cycle responses show temperature increases in excess of 9 degrees (RCP8.5) and even under aggressive mitigation (RCP2.6) temperatures in excess of 4 K. While the simulations point to much larger temperature ranges for emission driven experiments, they do not change existing expectations (based on previous concentration driven experiments) on the timescale that different sources of uncertainty are important. The new simulations sample a range of future atmospheric concentrations for each emission scenario. Both in case of SRES A1B and the Representative Concentration Pathways (RCPs), the concentration pathways used to drive GCM ensembles lies towards the lower end of our simulated distribution. This design decision (a legecy of previous assessments) is likely to lead concentration driven experiments to under-sample strong feedback responses in concentration driven projections. Our ensemble of emission driven simulations span the global temperature response of other multi-model frameworks except at the low end, where combinations of low climate sensitivity and low carbon cycle feedbacks lead to responses outside our ensemble range. The ensemble simulates a number of high end responses which lie above the CMIP5 carbon cycle range. These high end simulations can be linked to sampling a number of stronger carbon cycle feedbacks and to sampling climate sensitivities above 4.5 K. This latter aspect highlights the priority in identifying real world climate sensitivity constraints which, if achieved, would lead to reductions on the uppper bound of projected global mean temperature change. The ensembles of simulations presented here provides a framework to explore relationships between present day observables and future changes while the large spread of future projected changes, highlights the ongoing need for such work.

Numerical Prediction of CCV in a PFI Engine using a Parallel LES Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ameen, Muhsin M; Mirzaeian, Mohsen; Millo, Federico

Cycle-to-cycle variability (CCV) is detrimental to IC engine operation and can lead to partial burn, misfire, and knock. Predicting CCV numerically is extremely challenging due to two key reasons. Firstly, high-fidelity methods such as large eddy simulation (LES) are required to accurately resolve the incylinder turbulent flowfield both spatially and temporally. Secondly, CCV is experienced over long timescales and hence the simulations need to be performed for hundreds of consecutive cycles. Ameen et al. (Int. J. Eng. Res., 2017) developed a parallel perturbation model (PPM) approach to dissociate this long time-scale problem into several shorter timescale problems. The strategy ismore » to perform multiple single-cycle simulations in parallel by effectively perturbing the initial velocity field based on the intensity of the in-cylinder turbulence. This strategy was demonstrated for motored engine and it was shown that the mean and variance of the in-cylinder flowfield was captured reasonably well by this approach. In the present study, this PPM approach is extended to simulate the CCV in a fired port-fuel injected (PFI) SI engine. Two operating conditions are considered – a medium CCV operating case corresponding to 2500 rpm and 16 bar BMEP and a low CCV case corresponding to 4000 rpm and 12 bar BMEP. The predictions from this approach are also shown to be similar to the consecutive LES cycles. Both the consecutive and PPM LES cycles are observed to under-predict the variability in the early stage of combustion. The parallel approach slightly underpredicts the cyclic variability at all stages of combustion as compared to the consecutive LES cycles. However, it is shown that the parallel approach is able to predict the coefficient of variation (COV) of the in-cylinder pressure and burn rate related parameters with sufficient accuracy, and is also able to predict the qualitative trends in CCV with changing operating conditions. The convergence of the statistics predicted by the PPM approach with respect to the number of consecutive cycles required for each parallel simulation is also investigated. It is shown that this new approach is able to give accurate predictions of the CCV in fired engines in less than one-tenth of the time required for the conventional approach of simulating consecutive engine cycles.« less

New Tools for Embryo Selection: Comprehensive Chromosome Screening by Array Comparative Genomic Hybridization

PubMed Central

Cobo, Ana Cristina; Milán, Miguel; Al-Asmar, Nasser; García-Herrero, Sandra; Mir, Pere; Simón, Carlos

2014-01-01

The objective of this study was to evaluate the usefulness of comprehensive chromosome screening (CCS) using array comparative genomic hybridization (aCGH). The study included 1420 CCS cycles for recurrent miscarriage (n = 203); repetitive implantation failure (n = 188); severe male factor (n = 116); previous trisomic pregnancy (n = 33); and advanced maternal age (n = 880). CCS was performed in cycles with fresh oocytes and embryos (n = 774); mixed cycles with fresh and vitrified oocytes (n = 320); mixed cycles with fresh and vitrified day-2 embryos (n = 235); and mixed cycles with fresh and vitrified day-3 embryos (n = 91). Day-3 embryo biopsy was performed and analyzed by aCGH followed by day-5 embryo transfer. Consistent implantation (range: 40.5–54.2%) and pregnancy rates per transfer (range: 46.0–62.9%) were obtained for all the indications and independently of the origin of the oocytes or embryos. However, a lower delivery rate per cycle was achieved in women aged over 40 years (18.1%) due to the higher percentage of aneuploid embryos (85.3%) and lower number of cycles with at least one euploid embryo available per transfer (40.3%). We concluded that aneuploidy is one of the major factors which affect embryo implantation. PMID:24877108

Long-term outcomes after adjunctive topical 5-flurouracil or mitomycin C for the treatment of surgically excised, localized ocular surface squamous neoplasia.

PubMed

Bahrami, Bobak; Greenwell, Timothy; Muecke, James S

2014-01-01

To report rates of recurrence and complications of localized ocular surface squamous neoplasia treated with 5-fluorouracil or mitomycin C as adjunctive treatment to surgical excision. Long-term follow up of two prospective, non-comparative interventional case series. One hundred fifty-three eyes with histologically confirmed localized, non-invasive ocular surface squamous neoplasia. 89 eyes were treated with adjuvant 5-fluorouracil and 64 eyes were treated with adjuvant mitomycin C. Following surgical excision±cryotherapy patients received topical 5-fluorouracil 1% four times daily for two weeks or topical mitomycin C 0.04% four times daily for two to three 1-week cycles. Ocular surface squamous neoplasia recurrence, complications of therapy and compliance. Median follow up was 33.6 (range 12-84) months and 57.9 (range 12-160) months in 5-fluorouracil and mitomycin C groups, respectively. There was one recurrence in the 5-fluorouracil group and no recurrences in the mitomycin C group. Side-effects occurred in 69% of 5-fluorouracil patients and 41% of mitomycin C patients. Five patients (6%) required intervention for treatment-related side-effects in the 5-fluorouracil group versus 11 (17%) in the mitomycin C group. No vision-threatening complications were noted. Long-term recurrence of localised ocular surface squamous neoplasia is rare when topical 5-fluorouracil or mitomycin C are used as adjunctive treatment to surgical excision. While side-effects are common, the majority are transient and rarely limit compliance. © 2013 Royal Australian and New Zealand College of Ophthalmologists.

Pulsed Radiofrequency: A Management Option for Recurrent Trigeminal Neuralgia Following Radiofrequency Thermocoagulation.

PubMed

Liao, Chenlong; Visocchi, Massimiliano; Yang, Min; Liu, Pengfei; Li, Shiting; Zhang, Wenchuan

2017-01-01

Pain relief comparable with radiofrequency thermocoagulation (RFT) alone and fewer side effects than RFT have been achieved by combination treatment with pulsed radiofrequency (PRF) and short-duration RFT in trigeminal neuralgia (TN). We report the successful management of recurrent TN after RFT with single PRF in 2 patients. The RFT treatment was performed in 2-3 cycles for each division, with the lesion setting at 75°C-80°C for 90 seconds. The PRF treatment was applied for 120 seconds, with a generator output of 45 V, not exceeding a temperature of 42°C at the tip of the electrode. In case 1, pain relief was immediately achieved by RFT (75°C for 90 seconds), with moderate hypesthesia. Relapse of the triggered pain occurred 6 months later, and PRF was then applied. Long-term (18 months) pain relief without any additional pharmacologic or other treatment was reported. In case 2, a second RFT treatment at a higher temperature (80°C) was performed after recurrence after the first RFT within a week. Accompanied by worse hypesthesia, complete pain relief lasted for 6 months until the recurrence of pain was triggered by toothbrushing. PRF was then applied, and complete analgesia with long-term follow-up (28 months) was achieved. The PRF treatment for recurrent TN after RFT in this study could be viewed as a combination of PRF and RFT treatments in succession. Therefore, PRF and RFT should be considered to be complementary rather than alternative in the management of TN. Copyright © 2016 Elsevier Inc. All rights reserved.

Recurrent flow analysis in spatiotemporally chaotic 2-dimensional Kolmogorov flow

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lucas, Dan, E-mail: dan.lucas@ucd.ie; Kerswell, Rich R., E-mail: r.r.kerswell@bris.ac.uk

2015-04-15

Motivated by recent success in the dynamical systems approach to transitional flow, we study the efficiency and effectiveness of extracting simple invariant sets (recurrent flows) directly from chaotic/turbulent flows and the potential of these sets for providing predictions of certain statistics of the flow. Two-dimensional Kolmogorov flow (the 2D Navier-Stokes equations with a sinusoidal body force) is studied both over a square [0, 2π]{sup 2} torus and a rectangular torus extended in the forcing direction. In the former case, an order of magnitude more recurrent flows are found than previously [G. J. Chandler and R. R. Kerswell, “Invariant recurrent solutionsmore » embedded in a turbulent two-dimensional Kolmogorov flow,” J. Fluid Mech. 722, 554–595 (2013)] and shown to give improved predictions for the dissipation and energy pdfs of the chaos via periodic orbit theory. Analysis of the recurrent flows shows that the energy is largely trapped in the smallest wavenumbers through a combination of the inverse cascade process and a feature of the advective nonlinearity in 2D. Over the extended torus at low forcing amplitudes, some extracted states mimic the statistics of the spatially localised chaos present surprisingly well recalling the findings of Kawahara and Kida [“Periodic motion embedded in plane Couette turbulence: Regeneration cycle and burst,” J. Fluid Mech. 449, 291 (2001)] in low-Reynolds-number plane Couette flow. At higher forcing amplitudes, however, success is limited highlighting the increased dimensionality of the chaos and the need for larger data sets. Algorithmic developments to improve the extraction procedure are discussed.« less

Mechanical properties of Inconel 718 and Nickel 201 alloys after thermal histories simulating brazing and high temperature service

NASA Technical Reports Server (NTRS)

James, W. F.

1985-01-01

An experimental investigation was made to evaluate two nickel base alloys (Nickel-201 and Inconel-718) in three heat treated conditions. These conditions were: (1) annealed; (2) after thermal exposure simulating a braze cycle; and (3) after a thermal exposure simulating a braze cycle plus one operational lifetime of high temperature service. For the Nickel-201, two different braze cycle temperatures were evaluated. A braze cycle utilizing a lower braze temperature resulted in less grain growth for Nickel-201 than the standard braze cycle used for joining Nickel-201 to Inconel-718. It was determined, however, that Nickel-201, was marginal for temperatures investigated due to large grain growth. After the thermal exposures described above, the mechanical properties of Nickel-201 were degraded, whereas similar exposure on Inconel-718 actually strengthened the material compared with the annealed condition. The investigation included tensile tests at both room temperature and elevated temperatures, stress-rupture tests, and metallographic examination.

Updates on Modeling the Water Cycle with the NASA Ames Mars Global Climate Model

NASA Technical Reports Server (NTRS)

Kahre, M. A.; Haberle, R. M.; Hollingsworth, J. L.; Montmessin, F.; Brecht, A. S.; Urata, R.; Klassen, D. R.; Wolff, M. J.

2017-01-01

Global Circulation Models (GCMs) have made steady progress in simulating the current Mars water cycle. It is now widely recognized that clouds are a critical component that can significantly affect the nature of the simulated water cycle. Two processes in particular are key to implementing clouds in a GCM: the microphysical processes of formation and dissipation, and their radiative effects on heating/ cooling rates. Together, these processes alter the thermal structure, change the dynamics, and regulate inter-hemispheric transport. We have made considerable progress representing these processes in the NASA Ames GCM, particularly in the presence of radiatively active water ice clouds. We present the current state of our group's water cycle modeling efforts, show results from selected simulations, highlight some of the issues, and discuss avenues for further investigation.­

NETL to establish Dynamic Simulation Research and Training Center to promote IGCC technology with CO2 cpture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Provost, G.; Zitney, S.; Turton, R.

2009-01-01

To meet increasing demand for education and experience with commercial-scale, coal-fired, integrated gasification combined cycle (IGCC) plants with CO2 capture, the Department of Energy’s (DOE) National Energy Technology Laboratory (NETL) is leading a project to deploy a generic, full-scope, real-time IGCC dynamic plant simulator for use in establishing a world-class research and training center, and to promote and demonstrate IGCC technology to power industry personnel. The simulator, being built by Invensys Process Systems (IPS), will be installed at two separate sites, at NETL and West Virginia University (WVU), and will combine a process/gasification simulator with a power/combined-cycle simulator together inmore » a single dynamic simulation framework for use in engineering research studies and training applications. The simulator, scheduled to be launched in mid-year 2010, will have the following capabilities: High-fidelity, dynamic model of process-side (gasification and gas cleaning with CO2 capture) and power-block-side (combined cycle) for a generic IGCC plant fueled by coal and/or petroleum coke. Highly flexible configuration that allows concurrent training on separate gasification and combined cycle simulators, or up to two IGCC simulators. Ability to enhance and modify the plant model to facilitate studies of changes in plant configuration, equipment, and control strategies to support future R&D efforts. Training capabilities including startup, shutdown, load following and shedding, response to fuel and ambient condition variations, control strategy analysis (turbine vs. gasifier lead, etc.), representative malfunctions/trips, alarms, scenarios, trending, snapshots, data historian, etc. To support this effort, process descriptions and control strategies were developed for key sections of the plant as part of the detailed functional specification, which is serving as the basis of the simulator development. In this paper, we highlight the contents of the detailed functional specification for the simulator. We also describe the engineering, design, and expert testing process that the simulator will undergo in order to ensure that maximum fidelity is built into the generic simulator. Future applications and training programs associated with gasification, combined cycle, and IGCC simulations are discussed, including plant operation and control demonstrations, as well as education and training services.« less

Low-complexity nonlinear adaptive filter based on a pipelined bilinear recurrent neural network.

PubMed

Zhao, Haiquan; Zeng, Xiangping; He, Zhengyou

2011-09-01

To reduce the computational complexity of the bilinear recurrent neural network (BLRNN), a novel low-complexity nonlinear adaptive filter with a pipelined bilinear recurrent neural network (PBLRNN) is presented in this paper. The PBLRNN, inheriting the modular architectures of the pipelined RNN proposed by Haykin and Li, comprises a number of BLRNN modules that are cascaded in a chained form. Each module is implemented by a small-scale BLRNN with internal dynamics. Since those modules of the PBLRNN can be performed simultaneously in a pipelined parallelism fashion, it would result in a significant improvement of computational efficiency. Moreover, due to nesting module, the performance of the PBLRNN can be further improved. To suit for the modular architectures, a modified adaptive amplitude real-time recurrent learning algorithm is derived on the gradient descent approach. Extensive simulations are carried out to evaluate the performance of the PBLRNN on nonlinear system identification, nonlinear channel equalization, and chaotic time series prediction. Experimental results show that the PBLRNN provides considerably better performance compared to the single BLRNN and RNN models.

Diagonal recurrent neural network based adaptive control of nonlinear dynamical systems using lyapunov stability criterion.

PubMed

Kumar, Rajesh; Srivastava, Smriti; Gupta, J R P

2017-03-01

In this paper adaptive control of nonlinear dynamical systems using diagonal recurrent neural network (DRNN) is proposed. The structure of DRNN is a modification of fully connected recurrent neural network (FCRNN). Presence of self-recurrent neurons in the hidden layer of DRNN gives it an ability to capture the dynamic behaviour of the nonlinear plant under consideration (to be controlled). To ensure stability, update rules are developed using lyapunov stability criterion. These rules are then used for adjusting the various parameters of DRNN. The responses of plants obtained with DRNN are compared with those obtained when multi-layer feed forward neural network (MLFFNN) is used as a controller. Also, in example 4, FCRNN is also investigated and compared with DRNN and MLFFNN. Robustness of the proposed control scheme is also tested against parameter variations and disturbance signals. Four simulation examples including one-link robotic manipulator and inverted pendulum are considered on which the proposed controller is applied. The results so obtained show the superiority of DRNN over MLFFNN as a controller. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Evidence for a compulsive-like behavior in rats exposed to alternate access to highly preferred palatable food.

PubMed

Rossetti, Clara; Spena, Giuseppe; Halfon, Olivier; Boutrel, Benjamin

2014-11-01

Converging evidence suggests that recurrent excessive calorie restriction causes binge eating by promoting behavioral disinhibition and overeating. This interpretation suggests that cognitive adaptations may surpass physiological regulations of metabolic needs after recurrent cycles of dieting and binging. Intermittent access to palatable food has long been studied in rats, but the consequences of such diet cycling procedures on the cognitive control of food seeking remain unclear. Female Wistar rats were divided in two groups matched for food intake and body weight. One group received standard chow pellets 7 days/week, whereas the second group was given chow pellets for 5 days and palatable food for 2 days over seven consecutive weeks. Rats were also trained for operant conditioning. Intermittent access to palatable food elicited binging behavior and reduced intake of normal food. Rats with intermittent access to palatable food failed to exhibit anxiety-like behaviors in the elevated plus maze, but displayed reduced locomotor activity in the open field and developed a blunted corticosterone response following an acute stress across the diet procedure. Trained under a progressive ratio schedule, both groups exhibited the same motivation for sweetened food pellets. However, in contrast to controls, rats with a history of dieting and binging exhibited a persistent compulsive-like behavior when access to preferred pellets was paired with mild electrical foot shock punishments. These results highlight the intricate development of anxiety-like disorders and cognitive deficits leading to a loss of control over preferred food intake after repetitive cycles of intermittent access to palatable food. © 2013 Society for the Study of Addiction.

Statistical analysis of mixed recurrent event data with application to cancer survivor study

PubMed Central

Zhu, Liang; Tong, Xingwei; Zhao, Hui; Sun, Jianguo; Srivastava, Deo Kumar; Leisenring, Wendy; Robison, Leslie L.

2014-01-01

Event history studies occur in many fields including economics, medical studies and social science. In such studies concerning some recurrent events, two types of data have been extensively discussed in the literature. One is recurrent event data that arise if study subjects are monitored or observed continuously. In this case, the observed information provides the times of all occurrences of the recurrent events of interest. The other is panel count data, which occur if the subjects are monitored or observed only periodically. This can happen if the continuous observation is too expensive or not practical and in this case, only the numbers of occurrences of the events between subsequent observation times are available. In this paper, we discuss a third type of data, which is a mixture of recurrent event and panel count data and for which there exists little literature. For regression analysis of such data, a marginal mean model is presented and we propose an estimating equation-based approach for estimation of regression parameters. A simulation study is conducted to assess the finite sample performance of the proposed methodology and indicates that it works well for practical situations. Finally it is applied to a motivating study on childhood cancer survivors. PMID:23139023

Computational Modeling and Numerical Methods for Spatiotemporal Calcium Cycling in Ventricular Myocytes

PubMed Central

Nivala, Michael; de Lange, Enno; Rovetti, Robert; Qu, Zhilin

2012-01-01

Intracellular calcium (Ca) cycling dynamics in cardiac myocytes is regulated by a complex network of spatially distributed organelles, such as sarcoplasmic reticulum (SR), mitochondria, and myofibrils. In this study, we present a mathematical model of intracellular Ca cycling and numerical and computational methods for computer simulations. The model consists of a coupled Ca release unit (CRU) network, which includes a SR domain and a myoplasm domain. Each CRU contains 10 L-type Ca channels and 100 ryanodine receptor channels, with individual channels simulated stochastically using a variant of Gillespie’s method, modified here to handle time-dependent transition rates. Both the SR domain and the myoplasm domain in each CRU are modeled by 5 × 5 × 5 voxels to maintain proper Ca diffusion. Advanced numerical algorithms implemented on graphical processing units were used for fast computational simulations. For a myocyte containing 100 × 20 × 10 CRUs, a 1-s heart time simulation takes about 10 min of machine time on a single NVIDIA Tesla C2050. Examples of simulated Ca cycling dynamics, such as Ca sparks, Ca waves, and Ca alternans, are shown. PMID:22586402

On the Relationship Between Solar Wind Speed, Geomagnetic Activity, and the Solar Cycle Using Annual Values

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2008-01-01

The aa index can be decomposed into two separate components: the leading sporadic component due to solar activity as measured by sunspot number and the residual or recurrent component due to interplanetary disturbances, such as coronal holes. For the interval 1964-2006, a highly statistically important correlation (r = 0.749) is found between annual averages of the aa index and the solar wind speed (especially between the residual component of aa and the solar wind speed, r = 0.865). Because cyclic averages of aa (and the residual component) have trended upward during cycles 11-23, cyclic averages of solar wind speed are inferred to have also trended upward.

Thinking outside the channel: modeling nitrogen cycling in networked river ecosystems

Treesearch

Ashley M. Helton; Geoffrey C. Poole; Judy L. Meyer; Wilfred M. Wollheim; Bruce J. Peterson; Patrick J. Mulholland; Emily S. Bernhardt; Jack A. Stanford; Clay Arango; Linda R. Ashkenas; Lee W. Cooper; Walter K. Dodds; Stanley V. Gregory; Robert O. Hall; Stephen K. Hamilton; Sherri L. Johnson; William H. McDowell; Jody D. Potter; Jennifer L. Tank; Suzanne M. Thomas; H. Maurice Valett; Jackson R. Webster; Lydia Zeglin

2011-01-01

Agricultural and urban development alters nitrogen and other biogeochemical cycles in rivers worldwide. Because such biogeochemical processes cannot be measured empirically across whole river networks, simulation models are critical tools for understanding river-network biogeochemistry. However, limitations inherent in current models restrict our ability to simulate...

Poromechanics of stick-slip frictional sliding and strength recovery on tectonic faults

DOE PAGES

Scuderi, Marco M.; Carpenter, Brett M.; Johnson, Paul A.; ...

2015-10-22

Pore fluids influence many aspects of tectonic faulting including frictional strength aseismic creep and effective stress during the seismic cycle. But, the role of pore fluid pressure during earthquake nucleation and dynamic rupture remains poorly understood. Here we report on the evolution of pore fluid pressure and porosity during laboratory stick-slip events as an analog for the seismic cycle. We sheared layers of simulated fault gouge consisting of glass beads in a double-direct shear configuration under true triaxial stresses using drained and undrained fluid conditions and effective normal stress of 5–10 MPa. Shear stress was applied via a constant displacementmore » rate, which we varied in velocity step tests from 0.1 to 30 µm/s. Here, we observe net pore pressure increases, or compaction, during dynamic failure and pore pressure decreases, or dilation, during the interseismic period, depending on fluid boundary conditions. In some cases, a brief period of dilation is attendant with the onset of dynamic stick slip. Our data show that time-dependent strengthening and dynamic stress drop increase with effective normal stress and vary with fluid conditions. For undrained conditions, dilation and preseismic slip are directly related to pore fluid depressurization; they increase with effective normal stress and recurrence time. Microstructural observations confirm the role of water-activated contact growth and shear-driven elastoplastic processes at grain junctions. These results indicate that physicochemical processes acting at grain junctions together with fluid pressure changes dictate stick-slip stress drop and interseismic creep rates and thus play a key role in earthquake nucleation and rupture propagation.« less

Simulation and experiment of thermal fatigue in the CPV die attach

NASA Astrophysics Data System (ADS)

Bosco, Nick; Silverman, Timothy; Kurtz, Sarah

2012-10-01

FEM simulation and accelerated thermal cycling have been performed for the CPV die attach. Trends in fatigue damage accumulation and equivalent test time are explored and found to be most sensitive to temperature ramp rate. Die attach crack growth is measured through cycling and found to be in excellent agreement with simulations of the inelastic strain energy accumulated. Simulations of an entire year of weather data provides for the relative ranking of fatigue damage between four cities as well as their equivalent accelerated test time.

Post-recurrence chemotherapy for mesothelioma patients undergoing extrapleural pneumonectomy.

PubMed

Takuwa, Teruhisa; Hashimoto, Masaki; Matsumoto, Seiji; Kondo, Nobuyuki; Kuribayash, Kozo; Nakano, Takashi; Hasegawa, Seiki

2017-10-01

Additional chemotherapy is often not feasible in patients with recurrent malignant pleural mesothelioma (MPM) undergoing extrapleural pneumonectomy (EPP), due to deteriorated cardiopulmonary reserve. We thus examined the feasibility and efficacy of additional chemotherapy in patients with recurrent MPM after EPP. A retrospective review was conducted of 59 consecutive patients who underwent bi-/tri-modal treatment with induction chemotherapy, EPP, and radiation therapy from July 2004 to August 2013 at Hyogo College of Medicine (Nishinomiya, Japan). Of 59 patients, 39 (male/female = 31/8, right/left = 15/24, pathological stage I/II/III/IV = 1/7/23/3, bi-/tri-modality = 27/12) relapsed at a median age of 62 (range 37-71) years. The median time to recurrence after EPP was 11.6 months. Of the 39 relapsed patients, 12 received best supportive care alone, six started but discontinued chemotherapy, and the remaining 21 (53%) completed more than three cycles of intravenous chemotherapy. The median survival time after EPP was significantly longer in 21 patients who received additional chemotherapy than in 18 patients who did not (39.2 vs. 12.2 months, P = 0.009). Additional systemic chemotherapy was successfully administered in more than 50% of relapsed patients after bi-/tri-modal treatment, which included EPP, and resulted in a longer survival in comparison with best supportive care alone.

Variability of recurrence interval for New Zealand surface-rupturing paleoearthquakes

NASA Astrophysics Data System (ADS)

Nicol, A., , Prof; Robinson, R., Jr.; Van Dissen, R. J.; Harvison, A.

2015-12-01

Recurrence interval (RI) for successive earthquakes on individual faults is recorded by paleoseismic datasets for surface-rupturing earthquakes which, in New Zealand, have magnitudes of >Mw ~6 to 7.2 depending on the thickness of the brittle crust. New Zealand faults examined have mean RI of ~130 to 8500 yrs, with an upper bound censored by the sample duration (<30 kyr) and an inverse relationship to fault slip rate. Frequency histograms, probability density functions (PDFs) and coefficient of variation (CoV= standard deviation/arithmetic mean) values have been used to quantify RI variability for geological and simulated earthquakes on >100 New Zealand active faults. RI for individual faults can vary by more than an order of magnitude. CoV of RI for paleoearthquake data comprising 4-10 events ranges from ~0.2 to 1 with a mean of 0.6±0.2. These values are generally comparable to simulated earthquakes (>100 events per fault) and suggest that RI ranges from quasi periodic (e.g., ~0.2-0.5) to random (e.g., ~1.0). Comparison of earthquake simulation and paleoearthquake data indicates that the mean and CoV of RI can be strongly influenced by sampling artefacts including; the magnitude of completeness, the dimensionality of spatial sampling and the duration of the sample period. Despite these sampling issues RI for the best of the geological data (i.e. >6 events) and earthquake simulations are described by log-normal or Weibull distributions with long recurrence tails (~3 times the mean) and provide a basis for quantifying real RI variability (rather than sampling artefacts). Our analysis indicates that CoV of RI is negatively related to fault slip rate. These data are consistent with the notion that fault interaction and associated stress perturbations arising from slip on larger faults are more likely to advance or retard future slip on smaller faults than visa versa.

Advanced Nuclear Fuel Cycle Transitions: Optimization, Modeling Choices, and Disruptions

NASA Astrophysics Data System (ADS)

Carlsen, Robert W.

Many nuclear fuel cycle simulators have evolved over time to help understan the nuclear industry/ecosystem at a macroscopic level. Cyclus is one of th first fuel cycle simulators to accommodate larger-scale analysis with it liberal open-source licensing and first-class Linux support. Cyclus also ha features that uniquely enable investigating the effects of modeling choices o fuel cycle simulators and scenarios. This work is divided into thre experiments focusing on optimization, effects of modeling choices, and fue cycle uncertainty. Effective optimization techniques are developed for automatically determinin desirable facility deployment schedules with Cyclus. A novel method fo mapping optimization variables to deployment schedules is developed. Thi allows relationships between reactor types and scenario constraints to b represented implicitly in the variable definitions enabling the usage o optimizers lacking constraint support. It also prevents wasting computationa resources evaluating infeasible deployment schedules. Deployed power capacit over time and deployment of non-reactor facilities are also included a optimization variables There are many fuel cycle simulators built with different combinations o modeling choices. Comparing results between them is often difficult. Cyclus flexibility allows comparing effects of many such modeling choices. Reacto refueling cycle synchronization and inter-facility competition among othe effects are compared in four cases each using combinations of fleet of individually modeled reactors with 1-month or 3-month time steps. There are noticeable differences in results for the different cases. The larges differences occur during periods of constrained reactor fuel availability This and similar work can help improve the quality of fuel cycle analysi generally There is significant uncertainty associated deploying new nuclear technologie such as time-frames for technology availability and the cost of buildin advanced reactors. Historically, fuel cycle analysis has focused on answerin questions of fuel cycle feasibility and optimality. However, there has no been much work done to address uncertainty in fuel cycle analysis helpin answer questions of fuel cycle robustness. This work develops an demonstrates a methodology for evaluating deployment strategies whil accounting for uncertainty. Techniques are developed for measuring th hedging properties of deployment strategies under uncertainty. Additionally methods for using optimization to automatically find good hedging strategie are demonstrated.

Fermi-Pasta-Ulam auto recurrence in the description of the electrical activity of the heart.

PubMed

Novopashin, M A; Shmid, A V; Berezin, A A

2017-04-01

The authors proposed and mathematically described model of a new type of the Fermi-Pasta-Ulam recurrence (the FPU auto recurrence) and hypothesized an adequate description of the heart's electrical dynamics within the observed phenomenon. The dynamics of the FPU auto recurrence making appropriate electrical dynamics of the normal functioning of the heart in the form of an electrocardiogram (ECG) was obtained by a computer model study. The model solutions in the form of the FPU auto recurrence - ECG Fourier spectrum were evaluated for resistance to external disturbances in the form of random effects, as well as periodic perturbation at a frequency close to the heart beating rate of about 1Hz. In addition, in order to simulate the dynamics of myocardial infarction model, studied the effect of the surface area of the myocardium on the stability and shape of the auto recurrence - ECG spectrum. It has been found that the intense external disturbing periodic impacts at a frequency of about 1Hz lead to a sharp disturbance spectrum shape FPU auto recurrence - ECG structure. In addition, the decrease in the surface of the myocardium by 50% in the model led to the destruction of structures of the auto recurrence - ECG, which corresponds to the state of atrial myocardium. Research models have revealed a hypothetical basis of coronary heart disease in the form of increasing the energy of high-frequency harmonics spectrum of the auto recurrence by reducing the energy of low-frequency harmonic spectrum of the auto recurrence, which ultimately leads to a sharp decrease in myocardial contractility. In order to test the hypothesis has been studied more than 20,000 ECGs both healthy people and patients with cardiovascular disease. As a result of these studies, it was found that the dynamics of the electrical activity of normal functioning of the heart can be interpreted by the display of the detected by authors the FPU auto recurrence, and coronary heart disease is a violation of the energy ratio between the low and high frequency harmonics of the FPU auto recurrence Fourier spectrum equal to the ECG spectrum. Thus, the hypothesis has been confirmed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reactivity-controlled compression ignition drive cycle emissions and fuel economy estimations using vehicle system simulations

DOE PAGES

Curran, Scott J.; Gao, Zhiming; Wagner, Robert M.

2014-12-22

In-cylinder blending of gasoline and diesel to achieve reactivity-controlled compression ignition has been shown to reduce NO X and soot emissions while maintaining or improving brake thermal efficiency as compared with conventional diesel combustion. The reactivity-controlled compression ignition concept has an advantage over many advanced combustion strategies in that the fuel reactivity can be tailored to the engine speed and load, allowing stable low-temperature combustion to be extended over more of the light-duty drive cycle load range. In this paper, a multi-mode reactivity-controlled compression ignition strategy is employed where the engine switches from reactivity-controlled compression ignition to conventional diesel combustionmore » when speed and load demand are outside of the experimentally determined reactivity-controlled compression ignition range. The potential for reactivity-controlled compression ignition to reduce drive cycle fuel economy and emissions is not clearly understood and is explored here by simulating the fuel economy and emissions for a multi-mode reactivity-controlled compression ignition–enabled vehicle operating over a variety of US drive cycles using experimental engine maps for multi-mode reactivity-controlled compression ignition, conventional diesel combustion, and a 2009 port-fuel injected gasoline engine. Drive cycle simulations are completed assuming a conventional mid-size passenger vehicle with an automatic transmission. Multi-mode reactivity-controlled compression ignition fuel economy simulation results are compared with the same vehicle powered by a representative 2009 port-fuel injected gasoline engine over multiple drive cycles. Finally, engine-out drive cycle emissions are compared with conventional diesel combustion, and observations regarding relative gasoline and diesel tank sizes needed for the various drive cycles are also summarized.« less

Relationships between solar activity and climate change

NASA Technical Reports Server (NTRS)

Roberts, W. O.

1975-01-01

The relationship between recurrent droughts in the High Plains of the United States and the double sunspot cycle is discussed in detail. It is suggested that high solar activity is generally related to an increase in meridional circulation and blocking patterns at high and intermediate latitudes, especially in winter, and the effect is related to the sudden formation of cirrus clouds during strong geomagnetic activity that originates in the solar corpuscular emission.

Middle Pennsylvanian recurrent uplift of the Ouachita fold belt and basin subsidence in the Arkoma basin, Oklahoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elmore, R.D.; Sutherland, P.K.; White, P.B.

1990-09-01

Recurrent uplift of the Ouachita fold belt in Oklahoma coincided with the disruption of the Arkoma basin following the deposition of the Boggy Formation (early Desmoinesian time). The Boggy, composed of sandstone-shale sequences that record southerly progradation of coal-bearing, fluvially dominated deltaic complexes into the Arkoma basin, was folded at the time of uplift of the Ouachita fold belt. The uplift ended the progressive subsidence of the Arkoma basin and shifted the depocenter to the northwest. Subsequently, the Thurman Formation (middle Desmoinesian), which had a source in the southeast, was deposited in the smaller resurgent foreland basin over the foldedmore » and eroded surface of the Boggy. Chert-pebble conglomerates in the Thurman were derived from the erosion of newly elevated Ordovician and Devonian cherts in the core of the Ouachita foldbelt. Sandstone-shale packages are found in both formations. The origin of the coal-bearing cycles in the Boggy are enigmatic, but they probably were controlled by a combination of factors such as glacio-eustatic changes in sea level and delta-lobe abandonment. In contrast, cycles in the Thurman probably were strongly influenced by episodic thrust faulting and uplift in the Ouachitas.« less

Successful Management of Decitabine prior to Full-Dose Idarubicin and Cytarabine in the Treatment of Refractory/Recurrent Acute Myeloid Leukemia.

PubMed

Zhao, Hongyu; Xu, Li; Yang, Yongjian; Shao, Jianhua; Chen, Ping; Dong, Xuebin; Gu, Linping; Li, Daqi

2017-01-01

To investigate the safety and efficacy of the triple therapy of decitabine, idarubicin, and cytarabine in the treatment of refractory or recurrent acute myeloid leukemia (R/R AML). We conducted a single-center retrospective study in which decitabine treatment was administered prior to full-dose idarubicin and cytarabine (D-IA) for 21 R/R AML patients. After 1 cycle of D-IA, 10/21 (47.6%) patients experienced a complete remission (CR) and 2/21 (9.5%) showed a partial response. There was a 1-month response rate (RR) in 12/21 patients (57.14%); these patients achieved CR after 2 cycles of D-IA. Five of these 12 (40%) patients then received sequential allogeneic stem cell transplantation. At the last follow-up date, 9/21 (42.8%) patients had survived, and 7/21 (33.3%) were in continuous CR. Hematological toxicity and infections were the most prominent toxicities of this regimen. Other toxicities included nausea, vomiting, bleeding, and liver enzyme abnormalities. No mortalities were recorded due to treatment-related toxicity during remission. The combination was well tolerated, and the RR was encouraging. Our study suggests that D-IA may offer a novel and potentially effective treatment regimen for R/R AML patients. © 2017 S. Karger AG, Basel.

The tell-tale heart: A case of recurrent vulvar carcinoma with cardiac metastasis and review of literature.

PubMed

Jafri, Syed Imran Mustafa; Ali, Naveed; Farhat, Salman; Malik, Faizan; Shahin, Mark

2017-08-01

A 50-year-old female was diagnosed with vulvar cancer treated with left partial vulvectomy and bilateral lymphadenectomy. Ten months after her surgery, she presented with increased labial swelling, pain and discharge. Biopsy confirmed recurrence of squamous cell vulvar carcinoma. Incidentally, on restaging radiographic scans, she was found to have a large right ventricular mass which, after surgical debulking, was shown to be a squamous cell cancer of vulvar origin. She was commenced on chemotherapy with carboplatin and paclitaxel along with concurrent radiation therapy. Restaging PET scan showed persistent metastatic disease. She was switched to Cisplatin/Taxol after having hypersensitivity reaction to Carboplatin. She received 5 cycles with progression of disease in the follow up scans. She then received Nivolumab for 2 cycles. The patient then opted for comfort directed care given worsening functional status and progression of disease on repeat imaging. Secondary cardiac tumors are very rare and not extensively studied in oncology. Therefore, optimal management is not entirely clear. It is extremely rare for vulvar cancer to metastasize to the heart and only two cases have been reported in the literature. However, vulvar cancer metastasizing to the right ventricular cavity and endocardium has not been described before. We believe that this is the first ever such reported case.

Magnetotail Reconnection and Flux Circulation: Jupiter and Saturn Compared

NASA Technical Reports Server (NTRS)

Jackman, C. M.; Vogt, M. F.; Slavin, J. A.; Cowley, S. W. H.; Boardsen, S. A.

2011-01-01

The Jovian magnetosphere has been visited by eight spacecraft, and the magnetometer data have been used to identify dozens of plasmoids and 250 field dipolarizations associated with magnetic reconnection in the tail [e.g. Vogt et al., 2010]. Since the arrival of the Cassini spacecraft at Saturn in 2004, the magnetometer instrument has also been used to identify reconnection signatures. The deepest magnetotail orbits were in 2006, and during this time 34 signatures of plasmoids were identified. In this study we compare the statistical properties of plasmoids at Jupiter and Saturn such as duration, size, location, and recurrence period. Such parameters can be influenced by many factors, including the different Dungey cycle timescales and cross-magnetospheric potential drops at the two planets. We present superposed epoch analyses of plasmoids at the two planets to determine their average properties and to infer their role in the reconfiguration of the nightside of the magnetosphere. We examine the contributions of plasmoids to the magnetic flux transfer cycle at both planets. At Jupiter, there is evidence of an extended interval after reconnection where the field remains northward (analogous to the terrestrial post-plasmoid plasma sheet). At Saturn we see a similar feature, and calculate the amount of flux closed on average in reconnection events, leading us to an estimation of the recurrence rate of plasmoid release.

Pre-Clinical Evaluation of a Novel RXR Agonist for the Treatment of Neuroblastoma

PubMed Central

Waters, Alicia M.; Stewart, Jerry E.; Atigadda, Venkatram R.; Mroczek-Musulman, Elizabeth; Muccio, Donald D.; Grubbs, Clinton J.; Beierle, Elizabeth A.

2015-01-01

Neuroblastoma remains a common cause of pediatric cancer deaths, especially for children who present with advanced stage or recurrent disease. Currently, retinoic acid therapy is used as maintenance treatment to induce differentiation and reduce tumor recurrence following induction therapy for neuroblastoma, but unavoidable side effects are seen. A novel retinoid, UAB30, has been shown to generate negligible toxicities. In the current study, we hypothesized that UAB30 would have a significant impact on multiple neuroblastoma cell lines in vitro and in vivo. Cellular survival, cell cycle analysis, migration, and invasion were studied using alamarBlue® assays, FACS, and Transwell® assays, respectively, in multiple cell lines following treatment with UAB30. In addition, an in vivo murine model of human neuroblastoma was utilized to study the effects of UAB30 upon tumor xenograft growth and animal survival. We successfully demonstrated decreased cellular survival, invasion and migration, cell cycle arrest and increased apoptosis after treatment with UAB30. Furthermore, inhibition of tumor growth and increased survival was observed in a murine neuroblastoma xenograft model. The results of these in vitro and in vivo studies suggest a potential therapeutic role for the low toxicity synthetic retinoid X receptor selective agonist, UAB30, in neuroblastoma treatment. PMID:25944918

Multiple Origins and Nested Cycles of Hybridization Result in High Tetraploid Diversity in the Monocot Prospero.

PubMed

Jang, Tae-Soo; Parker, John S; Emadzade, Khatere; Temsch, Eva M; Leitch, Andrew R; Weiss-Schneeweiss, Hanna

2018-01-01

Polyploidy is a major driving force in angiosperm evolution, but our understanding of establishment and early diversification processes following allo- vs. auto-polyploidy is limited. An excellent system to address such questions is the monocot plant Prospero autumnale , as it comprises several genomically and chromosomally distinct diploid cytotypes and their auto- and allotetraploid derivatives. To infer origins and evolutionary trajectories of the tetraploids, we use genome size data, in situ hybridization with parental genomic DNAs and specific probes (satDNA, rDNAs), as well as molecular-phylogenetic analyses. Thus, we demonstrate that an astounding range of allotetraploid lineages has been formed recurrently by chromosomal re-patterning, interactions of chromosomally variable parental genomes and nested cycles of extensive hybridization, whereas autotetraploids have originated at least twice and are cytologically stable. During the recurrent formation and establishment across wide geographic areas hybridization in some populations could have inhibited lineage diversification and nascent speciation of such a hybrid swarm. However, cytotypes that became fixed in populations enhanced the potential for species diversification, possibly exploiting the extended allelic base, and fixed heterozygosity that polyploidy confers. The time required for polyploid cytotype fixation may in part reflect the lag phase reported for polyploids between their formation and species diversification.

[Life support of the Mars exploration crew. Control of a zeolite system for carbon dioxide removal from space cabin air within a closed air regeneration cycle].

PubMed

Chekov, Iu F

2009-01-01

The author describes a zeolite system for carbon dioxide removal integrated into a closed air regeneration cycle aboard spacecraft. The continuous operation of a double-adsorbent regeneration system with pCO2-dependable productivity is maintained through programmable setting of adsorption (desorption) semicycle time. The optimal system regulation curve is presented within the space of statistical performance family obtained in quasi-steady operating modes with controlled parameters of the recurrent adsorption-desorption cycle. The automatically changing system productivity ensures continuous intake of concentrated CO2. Control of the adsorption-desorption process is based on calculation of the differential adsorption (desorption) heat from gradient of adsorbent and test inert substance temperatures. The adaptive algorithm of digital control is implemented through the standard spacecraft interface with the board computer system and programmable microprocessor-based controllers.

Cyclic stressing and seismicity at strongly coupled subduction zones

USGS Publications Warehouse

Taylor, M.A.J.; Zheng, G.; Rice, J.R.; Stuart, W.D.; Dmowska, R.

1996-01-01

We use the finite element method to analyze stress variations in and near a strongly coupled subduction zone during an earthquake cycle. Deformation is assumed to be uniform along strike (plane strain on a cross section normal to the trench axis), and periodic earthquake slip is imposed consistent with the long-term rate of plate convergence and degree of coupling. Simulations of stress and displacement rate fields represent periodic fluctuations in time superimposed on an average field. The oceanic plate, descending slab, and continental lithosphere are assumed here to respond elastically to these fluctuations, and the remaining mantle under and between plates is assumed to respond as Maxwell viscoelastic. In the first part of the analysis we find that computed stress fluctuations in space and time are generally consistent with observed earthquake mechanism variations with time since a great thrust event. In particular, trench-normal extensional earthquakes tend to occur early in the earthquake cycle toward the outer rise but occur more abundantly late in the cycle in the subducting slab downdip of the main thrust zone. Compressional earthquakes, when they occur at all, have the opposite pattern. Our results suggest also that the actual timing of extensional outer rise events is controlled by the rheology of the shallow aseismic portion of the thrust interface. The second part of the analysis shows the effects of mantle relaxation on the rate of ground surface deformation during the earthquake cycle. Models without relaxation predict a strong overall compressional strain rate in the continental plate above the main thrust zone, with the strain rate constant between mainshocks. However with significant relaxation present, a localized region of unusually low compressional, or even slightly extensional, strain rate develops along the surface of the continental plate above and somewhat inland from the downdip edge of the locked main thrust zone. The low strain rate starts in the middle or late part of the cycle, depending on position. This result suggests that the negligible or small contraction measured on the Shumagin Islands, Alaska, during 1980 to 1991, may not invalidate an interpretation of that region as being a moderately coupled subduction zone. In contrast, mantle relaxation causes only modest temporal nonuniformity of uplift rates in the overriding plate and of extensional stress rates in the subducting plate, even when the Maxwell time is an order of magnitude less than the recurrence interval.

Low locoregional recurrence rates in patients treated after 2000 with doxorubicin based chemotherapy, modified radical mastectomy, and post-mastectomy radiation

PubMed Central

Greenbaum, Michael P.; Strom, Eric A.; Allen, Pamela K.; Perkins, George H.; Oh, Julia L.; Tereffe, Welela; Yu, Tse-Kuan; Buchholz, Thomas A.; Woodward, Wendy. A.

2011-01-01

Purpose To determine the rate of locoregional recurrence (LRR) associated with modern tri-modality therapy. Methods We retrospectively reviewed data from 291 consecutive PMRT patients treated from 1999 to 2001. These patients were compared to an historical group of 313 patients treated from 1979 to 1988 who had fluoroscopic simulation and contour-generated 2D planning. 1999–2001 spans the adoption of CT simulators for breast radiation therapy and a comparison was made between patients simulated before and after the implementation of CT simulation. Five-year actuarial rates for LRR, distal metastasis (DM), and overall survival (OS) between the pre and post CT simulation cohorts were compared as well. Results Compared to a 2D planned historic control, the combined contemporary patients had improved outcomes at 5 years for all endpoints studied; LRR 3.0% vs. 11.5%, DM 29.2% vs. 39.2%, and OS 79.2% vs. 70.6% (p = 0.0004, 0.0052, 0.0012, respectively). Significant factors in a multivariate analysis for LRR were: advanced T-stage (RR = 2.14, CI = 1.11–4.11, p = 0.023), and percent positive nodes (RR = 1.01, CI = 1.00–1.02, p = 0.012). The comparison of the pre and post CT-simulated PMRT patients (1999–2001) found no significant difference in any endpoint. Conclusions The rate of locoregional control for PMRT patients treated with modern radiotherapy is outstanding and has improved significantly compared to historical controls. PMID:20227126

RECURRENT EXPLOSIVE ERUPTIONS AND THE ''SIGMOID-TO-ARCADE'' TRANSFORMATION IN THE SUN DRIVEN BY DYNAMICAL MAGNETIC FLUX EMERGENCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Archontis, V.; Hood, A. W.; Tsinganos, K., E-mail: va11@st-andrews.ac.uk

2014-05-10

We report on three-dimensional MHD simulations of recurrent mini coronal mass ejection (CME)-like eruptions in a small active region (AR), which is formed by the dynamical emergence of a twisted (not kink unstable) flux tube from the solar interior. The eruptions develop as a result of the repeated formation and expulsion of new flux ropes due to continuous emergence and reconnection of sheared field lines along the polarity inversion line of the AR. The acceleration of the eruptions is triggered by tether-cutting reconnection at the current sheet underneath the erupting field. We find that each explosive eruption is followed bymore » reformation of a sigmoidal structure and a subsequent ''sigmoid-to-flare arcade'' transformation in the AR. These results might have implications for recurrent CMEs and eruptive sigmoids/flares observations and theoretical studies.« less

Pseudochaotic dynamics near global periodicity

NASA Astrophysics Data System (ADS)

Fan, Rong; Zaslavsky, George M.

2007-09-01

In this paper, we study a piecewise linear version of kicked oscillator model: saw-tooth map. A special case of global periodicity, in which every phase point belongs to a periodic orbit, is presented. With few analytic results known for the corresponding map on torus, we numerically investigate transport properties and statistical behavior of Poincaré recurrence time in two cases of deviation from global periodicity. A non-KAM behavior of the system, as well as subdiffusion and superdiffusion, are observed through numerical simulations. Statistics of Poincaré recurrences shows Kac lemma is valid in the system and there is a relation between the transport exponent and the Poincaré recurrence exponent. We also perform careful numerical computation of capacity, information and correlation dimensions of the so-called exceptional set in both cases. Our results show that the fractal dimension of the exceptional set is strictly less than 2 and that the fractal structures are unifractal rather than multifractal.

Memory replay in balanced recurrent networks

PubMed Central

Chenkov, Nikolay; Sprekeler, Henning; Kempter, Richard

2017-01-01

Complex patterns of neural activity appear during up-states in the neocortex and sharp waves in the hippocampus, including sequences that resemble those during prior behavioral experience. The mechanisms underlying this replay are not well understood. How can small synaptic footprints engraved by experience control large-scale network activity during memory retrieval and consolidation? We hypothesize that sparse and weak synaptic connectivity between Hebbian assemblies are boosted by pre-existing recurrent connectivity within them. To investigate this idea, we connect sequences of assemblies in randomly connected spiking neuronal networks with a balance of excitation and inhibition. Simulations and analytical calculations show that recurrent connections within assemblies allow for a fast amplification of signals that indeed reduces the required number of inter-assembly connections. Replay can be evoked by small sensory-like cues or emerge spontaneously by activity fluctuations. Global—potentially neuromodulatory—alterations of neuronal excitability can switch between network states that favor retrieval and consolidation. PMID:28135266

A One-Layer Recurrent Neural Network for Real-Time Portfolio Optimization With Probability Criterion.

PubMed

Liu, Qingshan; Dang, Chuangyin; Huang, Tingwen

2013-02-01

This paper presents a decision-making model described by a recurrent neural network for dynamic portfolio optimization. The portfolio-optimization problem is first converted into a constrained fractional programming problem. Since the objective function in the programming problem is not convex, the traditional optimization techniques are no longer applicable for solving this problem. Fortunately, the objective function in the fractional programming is pseudoconvex on the feasible region. It leads to a one-layer recurrent neural network modeled by means of a discontinuous dynamic system. To ensure the optimal solutions for portfolio optimization, the convergence of the proposed neural network is analyzed and proved. In fact, the neural network guarantees to get the optimal solutions for portfolio-investment advice if some mild conditions are satisfied. A numerical example with simulation results substantiates the effectiveness and illustrates the characteristics of the proposed neural network.

A numerical investigation of premixed combustion in wave rotors

NASA Technical Reports Server (NTRS)

Nalim, M. Razi; Paxson, Daniel E.

1996-01-01

Wave rotor cycles which utilize premixed combustion processes within the passages are examined numerically using a one-dimensional CFD-based simulation. Internal-combustion wave rotors are envisioned for use as pressure-gain combustors in gas turbine engines. The simulation methodology is described, including a presentation of the assumed governing equations for the flow and reaction in the channels, the numerical integration method used, and the modeling of external components such as recirculation ducts. A number of cycle simulations are then presented which illustrate both turbulent-deflagration and detonation modes of combustion. Estimates of performance and rotor wall temperatures for the various cycles are made, and the advantages and disadvantages of each are discussed.

Scenario and modelling uncertainty in global mean temperature change derived from emission-driven global climate models

NASA Astrophysics Data System (ADS)

Booth, B. B. B.; Bernie, D.; McNeall, D.; Hawkins, E.; Caesar, J.; Boulton, C.; Friedlingstein, P.; Sexton, D. M. H.

2013-04-01

We compare future changes in global mean temperature in response to different future scenarios which, for the first time, arise from emission-driven rather than concentration-driven perturbed parameter ensemble of a global climate model (GCM). These new GCM simulations sample uncertainties in atmospheric feedbacks, land carbon cycle, ocean physics and aerosol sulphur cycle processes. We find broader ranges of projected temperature responses arising when considering emission rather than concentration-driven simulations (with 10-90th percentile ranges of 1.7 K for the aggressive mitigation scenario, up to 3.9 K for the high-end, business as usual scenario). A small minority of simulations resulting from combinations of strong atmospheric feedbacks and carbon cycle responses show temperature increases in excess of 9 K (RCP8.5) and even under aggressive mitigation (RCP2.6) temperatures in excess of 4 K. While the simulations point to much larger temperature ranges for emission-driven experiments, they do not change existing expectations (based on previous concentration-driven experiments) on the timescales over which different sources of uncertainty are important. The new simulations sample a range of future atmospheric concentrations for each emission scenario. Both in the case of SRES A1B and the Representative Concentration Pathways (RCPs), the concentration scenarios used to drive GCM ensembles, lies towards the lower end of our simulated distribution. This design decision (a legacy of previous assessments) is likely to lead concentration-driven experiments to under-sample strong feedback responses in future projections. Our ensemble of emission-driven simulations span the global temperature response of the CMIP5 emission-driven simulations, except at the low end. Combinations of low climate sensitivity and low carbon cycle feedbacks lead to a number of CMIP5 responses to lie below our ensemble range. The ensemble simulates a number of high-end responses which lie above the CMIP5 carbon cycle range. These high-end simulations can be linked to sampling a number of stronger carbon cycle feedbacks and to sampling climate sensitivities above 4.5 K. This latter aspect highlights the priority in identifying real-world climate-sensitivity constraints which, if achieved, would lead to reductions on the upper bound of projected global mean temperature change. The ensembles of simulations presented here provides a framework to explore relationships between present-day observables and future changes, while the large spread of future-projected changes highlights the ongoing need for such work.

Postoperative maintenance levonorgestrel-releasing intrauterine system and endometrioma recurrence: a randomized controlled study.

PubMed

Chen, Yi-Jen; Hsu, Teh-Fu; Huang, Ben-Shian; Tsai, Hsiao-Wen; Chang, Yen-Hou; Wang, Peng-Hui

2017-06-01

According to 3 randomized trials, the levonorgestrel-releasing intrauterine system significantly reduced recurrent endometriosis-related pelvic pain at postoperative year 1. Only a few studies have evaluated the long-term effectiveness of the device for preventing endometrioma recurrence, and the effects of a levonorgestrel-releasing intrauterine system as a maintenance therapy remain unclear. The objective of the study was to evaluate whether a maintenance levonorgestrel-releasing intrauterine system is effective for preventing postoperative endometrioma recurrence. From May 2011 through March 2012, a randomized controlled trial including 80 patients with endometriomas undergoing laparoscopic cystectomy followed by six cycles of gonadotropin-releasing hormone agonist treatment was conducted. After surgery, the patients were randomized to groups that did or did not receive a levonorgestrel-releasing intrauterine system (intervention group, n = 40, vs control group, n = 40). The primary outcome was endometrioma recurrence 30 months after surgery. The secondary outcomes included dysmenorrhea, CA125 levels, noncyclic pelvic pain, and side effects. Endometrioma recurrence at 30 months did not significantly differ between the 2 groups (the intervention group, 10 of 40, 25% vs the control group 15 of 40, 37.5%; hazard ratio, 0.60, 95% confidence interval, 0.27-1.33, P = .209). The intervention group exhibited a lower dysmenorrhea recurrence rate, with an estimated hazard ratio of 0.32 (95% confidence interval, 0.12-0.83, P = .019). Over a 30 month follow-up, the intervention group exhibited a greater reduction in dysmenorrhea as assessed with a visual analog scale score (mean ± SD, 60.8 ± 25.5 vs 38.7 ± 25.9, P < .001, 95% confidence interval, 10.7-33.5), noncyclic pelvic pain visual analog scale score (39.1 ± 10.9 vs 30.1 ± 14.7, P = .014, 95% confidence interval, 1.9-16.1), and CA125 (median [interquartile range], -32.1 [-59.1 to 14.9], vs -15.6 [-33.0 to 5.0], P = .001) compared with the control group. The number-needed-to-treat benefit for dysmenorrhea recurrence at 30 months was 5. The number of recurrent cases requiring further surgical or hormone treatment in the intervention group (1 of 40, 2.5%, 95% confidence interval, -2.3% to 7.3%) was significantly lower than that in the control group (8 of 40, 20%, 95% confidence interval, 7.6-32.4%; P = .031). Long-term maintenance therapy using a levonorgestrel-releasing intrauterine system is not effective for preventing endometrioma recurrence. Copyright © 2017 Elsevier Inc. All rights reserved.

An experimental overview of the seismic cycle

NASA Astrophysics Data System (ADS)

Spagnuolo, E.; Violay, M.; Passelegue, F. X.; Nielsen, S. B.; Di Toro, G.

2017-12-01

Earthquake nucleation is the last stage of the inter-seismic cycle where the fault surface evolves through the interplay of friction, healing, stress perturbations and strain events. Slip stability under rate-and state friction has been extensively discussed in terms of loading point velocity and equivalent fault stiffness, but fault evolution towards seismic runaway under complex loading histories (e.g. slow variations of tectonic stress, stress transfer from impulsive nearby seismic events) is not yet fully investigated. Nevertheless, the short term earthquake forecasting is based precisely on a relation between seismic productivity and loading history which remains up to date still largely unresolved. To this end we propose a novel experimental approach which avails of a closed loop control of the shear stress, a nominally infinite equivalent slip and transducers for continuous monitoring of acoustic emissions. This experimental simulation allows us to study the stress dependency and temporal evolution of spontaneous slip events occurring on a pre-existing fault subjected to different loading histories. The experimental fault has an initial roughness which mimic a population of randomly distributed asperities, which here are used as a proxy for patches which are either far or close to failure on an extended fault. Our observations suggest that the increase of shear stress may trigger either spontaneous slow slip (creep) or short-lived stick-slip bursts, eventually leading to a fast slip instability (seismic runaway) when slip rates are larger than a few cm/s. The event type and the slip rate are regulated at first order by the background shear stress whereas the ultimate strength of the entire fault is dominated by the number of asperities close to failure under a stress step. The extrapolation of these results to natural conditions might explain the plethora of events that often characterize seismic sequences. Nonetheless this experimental approach helps the definition of a scaling relation between the loading rate and cumulated slip which is relevant to the definition of a recurrence model for the seismic cycle.

Single-pass memory system evaluation for multiprogramming workloads

NASA Technical Reports Server (NTRS)

Conte, Thomas M.; Hwu, Wen-Mei W.

1990-01-01

Modern memory systems are composed of levels of cache memories, a virtual memory system, and a backing store. Varying more than a few design parameters and measuring the performance of such systems has traditionally be constrained by the high cost of simulation. Models of cache performance recently introduced reduce the cost simulation but at the expense of accuracy of performance prediction. Stack-based methods predict performance accurately using one pass over the trace for all cache sizes, but these techniques have been limited to fully-associative organizations. This paper presents a stack-based method of evaluating the performance of cache memories using a recurrence/conflict model for the miss ratio. Unlike previous work, the performance of realistic cache designs, such as direct-mapped caches, are predicted by the method. The method also includes a new approach to the problem of the effects of multiprogramming. This new technique separates the characteristics of the individual program from that of the workload. The recurrence/conflict method is shown to be practical, general, and powerful by comparing its performance to that of a popular traditional cache simulator. The authors expect that the availability of such a tool will have a large impact on future architectural studies of memory systems.

Microbial mediation of biogeochemical cycles revealed by simulation of global changes with soil transplant and cropping

PubMed Central

Zhao, Mengxin; Xue, Kai; Wang, Feng; Liu, Shanshan; Bai, Shijie; Sun, Bo; Zhou, Jizhong; Yang, Yunfeng

2014-01-01

Despite microbes' key roles in driving biogeochemical cycles, the mechanism of microbe-mediated feedbacks to global changes remains elusive. Recently, soil transplant has been successfully established as a proxy to simulate climate changes, as the current trend of global warming coherently causes range shifts toward higher latitudes. Four years after southward soil transplant over large transects in China, we found that microbial functional diversity was increased, in addition to concurrent changes in microbial biomass, soil nutrient content and functional processes involved in the nitrogen cycle. However, soil transplant effects could be overridden by maize cropping, which was attributed to a negative interaction. Strikingly, abundances of nitrogen and carbon cycle genes were increased by these field experiments simulating global change, coinciding with higher soil nitrification potential and carbon dioxide (CO2) efflux. Further investigation revealed strong correlations between carbon cycle genes and CO2 efflux in bare soil but not cropped soil, and between nitrogen cycle genes and nitrification. These findings suggest that changes of soil carbon and nitrogen cycles by soil transplant and cropping were predictable by measuring microbial functional potentials, contributing to a better mechanistic understanding of these soil functional processes and suggesting a potential to incorporate microbial communities in greenhouse gas emission modeling. PMID:24694714

Detecting negative selection on recurrent mutations using gene genealogy

PubMed Central

2013-01-01

Background Whether or not a mutant allele in a population is under selection is an important issue in population genetics, and various neutrality tests have been invented so far to detect selection. However, detection of negative selection has been notoriously difficult, partly because negatively selected alleles are usually rare in the population and have little impact on either population dynamics or the shape of the gene genealogy. Recently, through studies of genetic disorders and genome-wide analyses, many structural variations were shown to occur recurrently in the population. Such “recurrent mutations” might be revealed as deleterious by exploiting the signal of negative selection in the gene genealogy enhanced by their recurrence. Results Motivated by the above idea, we devised two new test statistics. One is the total number of mutants at a recurrently mutating locus among sampled sequences, which is tested conditionally on the number of forward mutations mapped on the sequence genealogy. The other is the size of the most common class of identical-by-descent mutants in the sample, again tested conditionally on the number of forward mutations mapped on the sequence genealogy. To examine the performance of these two tests, we simulated recurrently mutated loci each flanked by sites with neutral single nucleotide polymorphisms (SNPs), with no recombination. Using neutral recurrent mutations as null models, we attempted to detect deleterious recurrent mutations. Our analyses demonstrated high powers of our new tests under constant population size, as well as their moderate power to detect selection in expanding populations. We also devised a new maximum parsimony algorithm that, given the states of the sampled sequences at a recurrently mutating locus and an incompletely resolved genealogy, enumerates mutation histories with a minimum number of mutations while partially resolving genealogical relationships when necessary. Conclusions With their considerably high powers to detect negative selection, our new neutrality tests may open new venues for dealing with the population genetics of recurrent mutations as well as help identifying some types of genetic disorders that may have escaped identification by currently existing methods. PMID:23651527

Thinking outside the channel: Modeling nitrogen cycling in networked river ecosystems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helton, Ashley; Poole, Geoffrey C.; Meyer, Judy

2011-01-01

Agricultural and urban development alters nitrogen and other biogeochemical cycles in rivers worldwide. Because such biogeochemical processes cannot be measured empirically across whole river networks, simulation models are critical tools for understanding river-network biogeochemistry. However, limitations inherent in current models restrict our ability to simulate biogeochemical dynamics among diverse river networks. We illustrate these limitations using a river-network model to scale up in situ measures of nitrogen cycling in eight catchments spanning various geophysical and land-use conditions. Our model results provide evidence that catchment characteristics typically excluded from models may control river-network biogeochemistry. Based on our findings, we identify importantmore » components of a revised strategy for simulating biogeochemical dynamics in river networks, including approaches to modeling terrestrial-aquatic linkages, hydrologic exchanges between the channel, floodplain/riparian complex, and subsurface waters, and interactions between coupled biogeochemical cycles.« less

Identification of miR-133b and RB1CC1 as independent predictors for biochemical recurrence and potential therapeutic targets for prostate cancer.

PubMed

Li, Xia; Wan, Xuechao; Chen, Hongbing; Yang, Shu; Liu, Yiyang; Mo, Wenjuan; Meng, Delong; Du, Wenting; Huang, Yan; Wu, Hai; Wang, Jingqiang; Li, Tao; Li, Yao

2014-05-01

We aimed to investigate the contribution of microRNA-133b (miR-133b) in prostate cancer cell proliferation, cell cycle, and apoptosis. We also examined expression of miR-133b in prostate cancer tissues, and evaluated the prognostic significance of miR-133b, as well as its target gene RB1CC1 in patients with prostate cancer after radical prostatectomy. miR-133b mimics (miR-133bm) and anti-miR-133b were transfected into LNCaP and PC-3 cells. CCK-8 was used to look at cell proliferation, flow cytometric analysis was carried out to study cell cycle, and apoptosis was determined by caspase-3 activity. miR-133b expression was assessed by real-time reverse transcription PCR and in situ hybridization in prostatic cell lines and 178 prostate tissue samples, respectively. The protein level of RB1CC1 was examined by Western blot and immunohistochemistry in prostatic cell lines and prostate tissue samples, respectively. Overexpression of miR-133b in LNCaP cells boosted cell proliferation and cell-cycle progression, but inhibited apoptosis; in contrast, miR-133bm promoted cell apoptosis, but suppressed cell proliferation and cell-cycle progression in PC-3 cells. In LNCaP cells, silencing of RB1CC1, a target of miR-133b, inhibited cell apoptosis, and promoted cell-cycle progression. Moreover, miR-133b expression was significantly inversely correlated with RB1CC1 expression in prostate cancer tissues. Multivariate Cox analysis indicated that miR-133b and RB1CC1 might be two independent prognostic factors of biochemical recurrence. miR-133b might enhance tumor-promoting properties in less aggressive LNCaP cells, whereas this miR may act as a tumor suppressor in more aggressive PC-3 cells. miR-133b and RB1CC1 were independent prognostic indicators for prostate cancer. ©2014 AACR.

Democratic population decisions result in robust policy-gradient learning: a parametric study with GPU simulations.

PubMed

Richmond, Paul; Buesing, Lars; Giugliano, Michele; Vasilaki, Eleni

2011-05-04

High performance computing on the Graphics Processing Unit (GPU) is an emerging field driven by the promise of high computational power at a low cost. However, GPU programming is a non-trivial task and moreover architectural limitations raise the question of whether investing effort in this direction may be worthwhile. In this work, we use GPU programming to simulate a two-layer network of Integrate-and-Fire neurons with varying degrees of recurrent connectivity and investigate its ability to learn a simplified navigation task using a policy-gradient learning rule stemming from Reinforcement Learning. The purpose of this paper is twofold. First, we want to support the use of GPUs in the field of Computational Neuroscience. Second, using GPU computing power, we investigate the conditions under which the said architecture and learning rule demonstrate best performance. Our work indicates that networks featuring strong Mexican-Hat-shaped recurrent connections in the top layer, where decision making is governed by the formation of a stable activity bump in the neural population (a "non-democratic" mechanism), achieve mediocre learning results at best. In absence of recurrent connections, where all neurons "vote" independently ("democratic") for a decision via population vector readout, the task is generally learned better and more robustly. Our study would have been extremely difficult on a desktop computer without the use of GPU programming. We present the routines developed for this purpose and show that a speed improvement of 5x up to 42x is provided versus optimised Python code. The higher speed is achieved when we exploit the parallelism of the GPU in the search of learning parameters. This suggests that efficient GPU programming can significantly reduce the time needed for simulating networks of spiking neurons, particularly when multiple parameter configurations are investigated.

Risk factors for conversion from unipolar psychotic depression to bipolar disorder.

PubMed

Østergaard, Søren Dinesen; Straszek, Sune; Petrides, Georgios; Skadhede, Søren; Jensen, Signe Olrik Wallenstein; Munk-Jørgensen, Povl; Nielsen, Jimmi

2014-03-01

Patients with unipolar psychotic depression (PD) are at high risk of developing bipolar disorder (BD). This conversion has important implications for the choice of treatment. This study, therefore, aimed to identify risk factors associated with diagnostic conversion from PD to BD. We conducted a population-based, historical prospective cohort study by merging data from Danish registers. Patients assigned an ICD-10 diagnosis of PD between 1 January 1995 and 31 December 2007 were identified in the Danish Central Psychiatric Research Register and were followed until the development of BD, death, loss to follow-up, or 31 December 2007. Potential risk factors for conversion to BD, also defined through various Danish registers, were tested in multiple logistic regression analyses with risk expressed as adjusted odds ratios (AOR). We identified 8,588 patients with PD, of whom 609 (7.1%) developed BD during follow-up. The following characteristics were significantly associated with diagnostic conversion from PD to BD: early onset of PD [AOR = 0.99 (per year of increasing age), p = 0.044], recurrent depression [AOR = 1.02 (per episode), p = 0.036], living alone (AOR = 1.29, p = 0.007), receiving a disability pension (AOR = 1.55, p < 0.001), and the highest educational level being a technical education (AOR = 1.55, p < 0.001), short-cycle higher education (AOR = 2.65, p < 0.001), or medium-cycle higher education (AOR = 1.75, p < 0.001). Diagnostic conversion to BD was prevalent among patients with PD. The following characteristics were significantly associated with this conversion: early onset of PD, recurrent depression, living alone, receiving a disability pension, and the highest educational level being a technical education, short-cycle higher education, or medium-cycle higher education. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Influence of the preparation design and artificial aging on the fracture resistance of monolithic zirconia crowns.

PubMed

Mitov, Gergo; Anastassova-Yoshida, Yana; Nothdurft, Frank Phillip; von See, Constantin; Pospiech, Peter

2016-02-01

The aim of this study was to evaluate the fracture resistance and fracture behavior of monolithic zirconia crowns in accordance with the preparation design and aging simulation method. An upper first molar was prepared sequentially with three different preparation designs: shoulderless preparation, 0.4 mm chamfer and 0.8 mm chamfer preparation. For each preparation design, 30 monolithic zirconia crowns were fabricated. After cementation on Cr-Co alloy dies, the following artificial aging procedures were performed: (1) thermal cycling and mechanical loading (TCML): 5000 cycles of thermal cycling 5℃-55℃ and chewing simulation (1,200,000 cycles, 50 N); (2) Low Temperature Degradation simulation (LTD): autoclave treatment at 137℃, 2 bar for 3 hours and chewing simulation; and (3) no pre-treatment (control group). After artificial aging, the crowns were loaded until fracture. The mean values of fracture resistance varied between 3414 N (LTD; 0.8 mm chamfer preparation) and 5712 N (control group; shoulderless preparation). Two-way ANOVA analysis showed a significantly higher fracture loads for the shoulderless preparation, whereas no difference was found between the chamfer preparations. In contrast to TCML, after LTD simulation the fracture strength of monolithic zirconia crowns decreased significantly. The monolithic crowns tested in this study showed generally high fracture load values. Preparation design and LTD simulation had a significant influence on the fracture strength of monolithic zirconia crowns.

Self-organized topology of recurrence-based complex networks

NASA Astrophysics Data System (ADS)

Yang, Hui; Liu, Gang

2013-12-01

With the rapid technological advancement, network is almost everywhere in our daily life. Network theory leads to a new way to investigate the dynamics of complex systems. As a result, many methods are proposed to construct a network from nonlinear time series, including the partition of state space, visibility graph, nearest neighbors, and recurrence approaches. However, most previous works focus on deriving the adjacency matrix to represent the complex network and extract new network-theoretic measures. Although the adjacency matrix provides connectivity information of nodes and edges, the network geometry can take variable forms. The research objective of this article is to develop a self-organizing approach to derive the steady geometric structure of a network from the adjacency matrix. We simulate the recurrence network as a physical system by treating the edges as springs and the nodes as electrically charged particles. Then, force-directed algorithms are developed to automatically organize the network geometry by minimizing the system energy. Further, a set of experiments were designed to investigate important factors (i.e., dynamical systems, network construction methods, force-model parameter, nonhomogeneous distribution) affecting this self-organizing process. Interestingly, experimental results show that the self-organized geometry recovers the attractor of a dynamical system that produced the adjacency matrix. This research addresses a question, i.e., "what is the self-organizing geometry of a recurrence network?" and provides a new way to reproduce the attractor or time series from the recurrence plot. As a result, novel network-theoretic measures (e.g., average path length and proximity ratio) can be achieved based on actual node-to-node distances in the self-organized network topology. The paper brings the physical models into the recurrence analysis and discloses the spatial geometry of recurrence networks.

Self-organized topology of recurrence-based complex networks.

PubMed

Yang, Hui; Liu, Gang

2013-12-01

With the rapid technological advancement, network is almost everywhere in our daily life. Network theory leads to a new way to investigate the dynamics of complex systems. As a result, many methods are proposed to construct a network from nonlinear time series, including the partition of state space, visibility graph, nearest neighbors, and recurrence approaches. However, most previous works focus on deriving the adjacency matrix to represent the complex network and extract new network-theoretic measures. Although the adjacency matrix provides connectivity information of nodes and edges, the network geometry can take variable forms. The research objective of this article is to develop a self-organizing approach to derive the steady geometric structure of a network from the adjacency matrix. We simulate the recurrence network as a physical system by treating the edges as springs and the nodes as electrically charged particles. Then, force-directed algorithms are developed to automatically organize the network geometry by minimizing the system energy. Further, a set of experiments were designed to investigate important factors (i.e., dynamical systems, network construction methods, force-model parameter, nonhomogeneous distribution) affecting this self-organizing process. Interestingly, experimental results show that the self-organized geometry recovers the attractor of a dynamical system that produced the adjacency matrix. This research addresses a question, i.e., "what is the self-organizing geometry of a recurrence network?" and provides a new way to reproduce the attractor or time series from the recurrence plot. As a result, novel network-theoretic measures (e.g., average path length and proximity ratio) can be achieved based on actual node-to-node distances in the self-organized network topology. The paper brings the physical models into the recurrence analysis and discloses the spatial geometry of recurrence networks.

Self-organized topology of recurrence-based complex networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Hui, E-mail: huiyang@usf.edu; Liu, Gang

With the rapid technological advancement, network is almost everywhere in our daily life. Network theory leads to a new way to investigate the dynamics of complex systems. As a result, many methods are proposed to construct a network from nonlinear time series, including the partition of state space, visibility graph, nearest neighbors, and recurrence approaches. However, most previous works focus on deriving the adjacency matrix to represent the complex network and extract new network-theoretic measures. Although the adjacency matrix provides connectivity information of nodes and edges, the network geometry can take variable forms. The research objective of this article ismore » to develop a self-organizing approach to derive the steady geometric structure of a network from the adjacency matrix. We simulate the recurrence network as a physical system by treating the edges as springs and the nodes as electrically charged particles. Then, force-directed algorithms are developed to automatically organize the network geometry by minimizing the system energy. Further, a set of experiments were designed to investigate important factors (i.e., dynamical systems, network construction methods, force-model parameter, nonhomogeneous distribution) affecting this self-organizing process. Interestingly, experimental results show that the self-organized geometry recovers the attractor of a dynamical system that produced the adjacency matrix. This research addresses a question, i.e., “what is the self-organizing geometry of a recurrence network?” and provides a new way to reproduce the attractor or time series from the recurrence plot. As a result, novel network-theoretic measures (e.g., average path length and proximity ratio) can be achieved based on actual node-to-node distances in the self-organized network topology. The paper brings the physical models into the recurrence analysis and discloses the spatial geometry of recurrence networks.« less

Life Cycle of Tropical Convection and Anvil in Observations and Models

NASA Astrophysics Data System (ADS)

McFarlane, S. A.; Hagos, S. M.; Comstock, J. M.

2011-12-01

Tropical convective clouds are important elements of the hydrological cycle and produce extensive cirrus anvils that strongly affect the tropical radiative energy balance. To improve simulations of the global water and energy cycles and accurately predict both precipitation and cloud radiative feedbacks, models need to realistically simulate the lifecycle of tropical convection, including the formation and radiative properties of ice anvil clouds. By combining remote sensing datasets from precipitation and cloud radars at the Atmospheric Radiation Measurement (ARM) Darwin site with geostationary satellite data, we can develop observational understanding of the lifetime of convective systems and the links between the properties of convective systems and their associated anvil clouds. The relationships between convection and anvil in model simulations can then be compared to those seen in the observations to identify areas for improvement in the model simulations. We identify and track tropical convective systems in the Tropical Western Pacific using geostationary satellite observations. We present statistics of the tropical convective systems including size, age, and intensity and classify the lifecycle stage of each system as developing, mature, or dissipating. For systems that cross over the ARM Darwin site, information on convective intensity and anvil properties are obtained from the C-Pol precipitation radar and MMCR cloud radar, respectively, and are examined as a function of the system lifecycle. Initial results from applying the convective identification and tracking algorithm to a tropical simulation from the Weather Research and Forecasting (WRF) model run show that the model produces reasonable overall statistics of convective systems, but details of the life cycle (such as diurnal cycle, system tracks) differ from the observations. Further work will focus on the role of atmospheric temperature and moisture profiles in the model's convective life cycle.

FY13 GLYCOLIC-NITRIC ACID FLOWSHEET DEMONSTRATIONS OF THE DWPF CHEMICAL PROCESS CELL WITH SIMULANTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D.; Zamecnik, J.; Best, D.

Savannah River Remediation is evaluating changes to its current Defense Waste Processing Facility flowsheet to replace formic acid with glycolic acid in order to improve processing cycle times and decrease by approximately 100x the production of hydrogen, a potentially flammable gas. Higher throughput is needed in the Chemical Processing Cell since the installation of the bubblers into the melter has increased melt rate. Due to the significant maintenance required for the safety significant gas chromatographs and the potential for production of flammable quantities of hydrogen, eliminating the use of formic acid is highly desirable. Previous testing at the Savannah Rivermore » National Laboratory has shown that replacing formic acid with glycolic acid allows the reduction and removal of mercury without significant catalytic hydrogen generation. Five back-to-back Sludge Receipt and Adjustment Tank (SRAT) cycles and four back-to-back Slurry Mix Evaporator (SME) cycles were successful in demonstrating the viability of the nitric/glycolic acid flowsheet. The testing was completed in FY13 to determine the impact of process heels (approximately 25% of the material is left behind after transfers). In addition, back-to-back experiments might identify longer-term processing problems. The testing was designed to be prototypic by including sludge simulant, Actinide Removal Product simulant, nitric acid, glycolic acid, and Strip Effluent simulant containing Next Generation Solvent in the SRAT processing and SRAT product simulant, decontamination frit slurry, and process frit slurry in the SME processing. A heel was produced in the first cycle and each subsequent cycle utilized the remaining heel from the previous cycle. Lower SRAT purges were utilized due to the low hydrogen generation. Design basis addition rates and boilup rates were used so the processing time was shorter than current processing rates.« less

Surface Roughness of Composite Resins after Simulated Toothbrushing with Different Dentifrices.

PubMed

Monteiro, Bruna; Spohr, Ana Maria

2015-07-01

The aim of the study was to evaluate, in vitro, the surface roughness of two composite resins submitted to simulated toothbrushing with three different dentifrices. Totally, 36 samples of Z350XT and 36 samples of Empress Direct were built and randomly divided into three groups (n = 12) according to the dentifrice used (Oral-B Pro-Health Whitening [OBW], Colgate Sensitive Pro-Relief [CS], Colgate Total Clean Mint 12 [CT12]). The samples were submitted to 5,000, 10,000 or 20,000 cycles of simulated toothbrushing. After each simulated period, the surface roughness of the samples was measured using a roughness tester. According to three-way analysis of variance, dentifrice (P = 0.044) and brushing time (P = 0.000) were significant. The composite resin was not significant (P = 0.381) and the interaction among the factors was not significant (P > 0.05). The mean values of the surface roughness (µm) followed by the same letter represent no statistical difference by Tukey's post-hoc test (P <0.05): Dentifrice: CT12 = 0.269(a); CS Pro- Relief = 0.300(ab); OBW = 0.390(b). Brushing time: Baseline = 0,046ª; 5,000 cycles = 0.297(b); 10,000 cycles = 0.354(b); 20,000 cycles = 0.584(c). Z350 XT and Empress Direct presented similar surface roughness after all cycles of simulated toothbrushing. The higher the brushing time, the higher the surface roughness of composite resins. The dentifrice OBW caused a higher surface roughness in both composite resins.

Simulation of Changes in the Near-Surface Soil Freeze/Thaw Cycle Using CLM4.5 With Four Atmospheric Forcing Data Sets

NASA Astrophysics Data System (ADS)

Guo, Donglin; Wang, Aihui; Li, Duo; Hua, Wei

2018-03-01

Change in the near-surface soil freeze/thaw cycle is critical for assessments of hydrological activity, ecosystems, and climate change. Previous studies investigated the near-surface soil freeze/thaw cycle change mostly based on in situ observations and satellite monitoring. Here numerical simulation method is tested to estimate the long-term change in the near-surface soil freeze/thaw cycle in response to recent climate warming for its application to predictions. Four simulations are performed at 0.5° × 0.5° resolution from 1979 to 2009 using the Community Land Model version 4.5, each driven by one of the four atmospheric forcing data sets (i.e., one default Climate Research Unit-National Centers for Environmental Prediction [CRUNCEP] and three newly developed Modern Era Retrospective-Analysis for Research and Applications, Climate Forecast System Reanalysis, and European Centre for Medium-Range Weather Forecasts Reanalysis Interim). The observations from 299 weather stations in both Russia and China are employed to validate the simulated results. The results show that all simulations reasonably reproduce the observed variations in the ground temperature, the freeze start and end dates, and the freeze duration (the correlation coefficients range from 0.47 to 0.99, and the Nash-Sutcliffe efficiencies range from 0.19 to 0.98). Part of the simulations also exactly simulate the trends of the ground temperature, the freeze start and end dates, and the freeze duration. Of the four simulations, the results from the simulation using the CRUNCEP data set show the best overall agreement with the in situ observations, indicating that the CRUNCEP data set could be preferentially considered as the basic atmospheric forcing data set for future prediction. The simulated area-averaged annual freeze duration shortened by 8.03 days on average from 1979 to 2009, with an uncertainty (one standard deviation) of 0.67 days caused by the different atmospheric forcing data sets. These results address the performance of numerical model in simulating the long-term changes in the near-surface soil freeze/thaw cycle and the role of different atmospheric forcing data sets in the simulation, which are useful for the prediction of future freeze/thaw dynamics.

Towards an Automated Full-Turbofan Engine Numerical Simulation

NASA Technical Reports Server (NTRS)

Reed, John A.; Turner, Mark G.; Norris, Andrew; Veres, Joseph P.

2003-01-01

The objective of this study was to demonstrate the high-fidelity numerical simulation of a modern high-bypass turbofan engine. The simulation utilizes the Numerical Propulsion System Simulation (NPSS) thermodynamic cycle modeling system coupled to a high-fidelity full-engine model represented by a set of coupled three-dimensional computational fluid dynamic (CFD) component models. Boundary conditions from the balanced, steady-state cycle model are used to define component boundary conditions in the full-engine model. Operating characteristics of the three-dimensional component models are integrated into the cycle model via partial performance maps generated automatically from the CFD flow solutions using one-dimensional meanline turbomachinery programs. This paper reports on the progress made towards the full-engine simulation of the GE90-94B engine, highlighting the generation of the high-pressure compressor partial performance map. The ongoing work will provide a system to evaluate the steady and unsteady aerodynamic and mechanical interactions between engine components at design and off-design operating conditions.

Uniaxial low cycle fatigue behavior for pre-corroded 16MND5 bainitic steel in simulated pressurized water reactor environment

NASA Astrophysics Data System (ADS)

Chen, Xu; Ren, Bin; Yu, Dunji; Xu, Bin; Zhang, Zhe; Chen, Gang

2018-06-01

The effects of uniaxial tension properties and low cycle fatigue behavior of 16MND5 bainitic steel cylinder pre-corroded in simulated pressurized water reactor (PWR) were investigated by fatigue at room temperature in air and immersion test system, scanning electron microscopy (SEM), energy disperse spectroscopy (EDS). The experimental results indicated that the corrosion fatigue lives of 16MND5 specimen were significantly affected by the strain amplitude and simulated PWR environments. The compositions of corrosion products were complexly formed in simulated PWR environments. The porous corrosion surface of pre-corroded materials tended to generate pits as a result of promoting contact area to the fresh metal, which promoted crack initiation. For original materials, the fatigue cracks initiated at inclusions imbedded in the micro-cracks. Moreover, the simulated PWR environments degraded the mechanical properties and low cycle fatigue behavior of 16MND5 specimens remarkably. Pre-corrosion of 16MND5 specimen mainly affected the plastic term of the Coffin-Manson equation.

Analysis of Glenoid Fixation with Anatomic Total Shoulder Arthroplasty in an Extreme Cyclic Loading Scenario.

PubMed

Roche, Christopher P; Staunch, Cameron; Hahn, William; Grey, Sean G; Flurin, Pierre-Henri; Wright, Thomas W; Zuckerman, Joseph D

2015-12-01

ASTM F2028-14 was adopted to recom mend a cyclic eccentric glenoid edge loading test that simulates the rocking horse loading mechanism beleived to cause aTSA glenoid loosening. While this method accurately simulates that failure mechanism, the recommended 750 N load may not be sufficient to simulate worst-case loading magnitudes, and the recommended 100,000 cycles may not be sufficient to simulate device fatigue-related failure modes. Finally, if greater loading magnitude or a larger number of cycles is performed, the recommended substrate density may not be sufficiently strong to support the elevated loads and cycles. To this end, a new test method is proposed to supplement ASTM F2028-14. A series of cyclic tests were performed to evaluate the long-term fixation strength of two different hybrid glenoid designs in both low (15 pcf) and high (30 pcf) density polyurethane blocks at elevated loads relative to ASTM F2028-14. To simulate a worst case clinical condition in which the humeral head is superiorly migrated, a cyclic load was applied to the superior glenoid rim to induce a maximum torque on the fixation pegs for three different cyclic loading tests: 1. 1,250 N load for 0.75 M cycles in a 15 pcf block, 2. 1,250 N load for 1.5 M cycles in a 30 pcf block, and 3. 2,000 N load for 0.65 M cycles in a 30 pcf block. All devices completed cyclic loading without failure, fracture, or loss of fixation regardless of glenoid design, polyurethane density, loading magnitude, or cycle length. No significant difference in post-cyclic displacement was noted between designs in any of the three tests. Post-cyclic radiographs demonstrated that each device maintained fixa - tion with the metal pegs within the bone-substitute blocks with no fatigue related failures. These results demonstrate that both cemented hybrid glenoids maintained fixation when tested according to each cyclic loading scenario, with no difference in post-cyclic displacement observed between designs. The lack of fatigue-related failures in these elevated load and high cycle test scenarios are promising, as are the relatively low displacements given the extreme nature of each test. This cyclic loading method is intended to supplement the ASTM F2028-14 standard that adequately simulates the rocking horse loading mechanism but may not adequately simulate the fatigue-related failure modes.

A Simulation of Low and High Cycle Fatigue Failure Effects for Metal Matrix Composites Based on Innovative J2-Flow Elastoplasticity Model

PubMed Central

Wang, Zhaoling; Xiao, Heng

2017-01-01

New elastoplastic J2-flow constitutive equations at finite deformations are proposed for the purpose of simulating the fatigue failure behavior for metal matrix composites. A new, direct approach is established in a two-fold sense of unification. Namely, both low and high cycle fatigue failure effects of metal matrix composites may be simultaneously simulated for various cases of the weight percentage of reinforcing particles. Novel results are presented in four respects. First, both the yield condition and the loading–unloading conditions in a usual sense need not be involved but may be automatically incorporated into inherent features of the proposed constitutive equations; second, low-to-high cycle fatigue failure effects may be directly represented by a simple condition for asymptotic loss of the material strength, without involving any additional damage-like variables; third, both high and low cycle fatigue failure effects need not be separately treated but may be automatically derived as model predictions with a unified criterion for critical failure states, without assuming any ad hoc failure criteria; and, finally, explicit expressions for each incorporated model parameter changing with the weight percentage of reinforcing particles may be obtainable directly from appropriate test data. Numerical examples are presented for medium-to-high cycle fatigue failure effects and for complicated duplex effects from low to high cycle fatigue failure effects. Simulation results are in good agreement with experimental data. PMID:28946637

MATLAB Simulation of Gradient-Based Neural Network for Online Matrix Inversion

NASA Astrophysics Data System (ADS)

Zhang, Yunong; Chen, Ke; Ma, Weimu; Li, Xiao-Dong

This paper investigates the simulation of a gradient-based recurrent neural network for online solution of the matrix-inverse problem. Several important techniques are employed as follows to simulate such a neural system. 1) Kronecker product of matrices is introduced to transform a matrix-differential-equation (MDE) to a vector-differential-equation (VDE); i.e., finally, a standard ordinary-differential-equation (ODE) is obtained. 2) MATLAB routine "ode45" is introduced to solve the transformed initial-value ODE problem. 3) In addition to various implementation errors, different kinds of activation functions are simulated to show the characteristics of such a neural network. Simulation results substantiate the theoretical analysis and efficacy of the gradient-based neural network for online constant matrix inversion.

Analysis and simulation of the I C engine Otto cycle using the second law of thermodynamics

NASA Astrophysics Data System (ADS)

Abdel-Rahim, Y. M.

The present investigation is an application of the second law of thermodynamics to the spark ignition engine cycle. A comprehensive thermodynamic analysis of the air standard cycle is conducted using the first and second laws of thermodynamics, the ideal gas equation of state and the perfect gas properties for air. The study investigates the effect of the cycle parameters on the cycle performance reflected by the first and second law efficiencies, the heat added, the work done, the available energy added as well as the history of the internal, available and unavailable energies along the cycle. The study shows that the second law efficiency is a function of the compression ratio, the initial temperature, the maximum temperature as well as the dead state temperature. A non-dimensional comprehensive thermodynamic simulation model for the actual Otto cycle is developed to study the effects of the design and operating parameters of the cycle on the cycle performance. The analysis takes into account engine geometry, mixture strength, heat transfer, piston motion, engine speed, mechanical friction, spark advance and combustion duration.

Influence of fluctuations of historic water bodies on fault stability and earthquake recurrence interval: The Dead Sea Rift as a case study

NASA Astrophysics Data System (ADS)

Belferman, Mariana; Katsman, Regina; Agnon, Amotz; Ben-Avraham, Zvi

2017-04-01

Despite the global, social and scientific impact of earthquakes, their triggering mechanisms remain often poorly defined. We suggest that dynamic changes in the levels of the historic water bodies occupying tectonic depressions at the Dead Sea Rift cause significant variations in the shallow crustal stress field and affect local fault systems in a way that may promote or suppress earthquakes. This mechanism and its spatial and temporal scales differ from those in tectonically-driven deformations. We use analytical and numerical poroelastic models to simulate immediate and delayed seismic responses resulting from the observed historic water level changes. The role of variability in the poroelastic and the elastic properties of the rocks composing the upper crust in inducing or retarding deformations under a strike-slip faulting regime is studied. The solution allows estimating a possible reduction in a seismic recurrence interval. Considering the historic water level fluctuation, our preliminary simulations show a promising agreement with paleo-seismic rates identified in the field.

Semantic disturbance in schizophrenia and its relationship to the cognitive neuroscience of attention

PubMed Central

Nestor, P.G.; Han, S.D.; Niznikiewicz, M.; Salisbury, D.; Spencer, K.; Shenton, M.E.; McCarley, R.W.

2010-01-01

We view schizophrenia as producing a failure of attentional modulation that leads to a breakdown in the selective enhancement or inhibition of semantic/lexical representations whose biological substrata are widely distributed across left (dominant) temporal and frontal lobes. Supporting behavioral evidence includes word recall studies that have pointed to a disturbance in connectivity (associative strength) but not network size (number of associates) in patients with schizophrenia. Paralleling these findings are recent neural network simulation studies of the abnormal connectivity effect in schizophrenia through ‘lesioning’ network connection weights while holding constant network size. Supporting evidence at the level of biology are in vitro studies examining N-methyl-d-aspartate (NMDA) receptor antagonists on recurrent inhibition; simulations in neural populations with realistically modeled biophysical properties show NMDA antagonists produce a schizophrenia-like disturbance in pattern association. We propose a similar failure of NMDA-mediated recurrent inhibition as a candidate biological substrate for attention and semantic anomalies of schizophrenia. PMID:11454433

Simulating the Current Water Cycle with the NASA Ames Mars Global Climate Model

NASA Astrophysics Data System (ADS)

Kahre, M. A.; Haberle, R. M.; Hollingsworth, J. L.; Brecht, A. S.; Urata, R. A.; Montmessin, F.

2017-12-01

The water cycle is a critical component of the current Mars climate system, and it is now widely recognized that water ice clouds significantly affect the nature of the simulated water cycle. Two processes are key to implementing clouds in a Mars global climate model (GCM): the microphysical processes of formation and dissipation, and their radiative effects on atmospheric heating/cooling rates. Together, these processes alter the thermal structure, change the atmospheric dynamics, and regulate inter-hemispheric transport. We have made considerable progress using the NASA Ames Mars GCM to simulate the current-day water cycle with radiatively active clouds. Cloud fields from our baseline simulation are in generally good agreement with observations. The predicted seasonal extent and peak IR optical depths are consistent MGS/TES observations. Additionally, the thermal response to the clouds in the aphelion cloud belt (ACB) is generally consistent with observations and other climate model predictions. Notably, there is a distinct gap in the predicted clouds over the North Residual Cap (NRC) during local summer, but the clouds reappear in this simulation over the NRC earlier than the observations indicate. Polar clouds are predicted near the seasonal CO2 ice caps, but the column thicknesses of these clouds are generally too thick compared to observations. Our baseline simulation is dry compared to MGS/TES-observed water vapor abundances, particularly in the tropics and subtropics. These areas of disagreement appear to be a consistent with other current water cycle GCMs. Future avenues of investigation will target improving our understanding of what controls the vertical extent of clouds and the apparent seasonal evolution of cloud particle sizes within the ACB.

Unraveling the martian water cycle with high-resolution global climate simulations

NASA Astrophysics Data System (ADS)

Pottier, Alizée; Forget, François; Montmessin, Franck; Navarro, Thomas; Spiga, Aymeric; Millour, Ehouarn; Szantai, André; Madeleine, Jean-Baptiste

2017-07-01

Global climate modeling of the Mars water cycle is usually performed at relatively coarse resolution (200 - 300km), which may not be sufficient to properly represent the impact of waves, fronts, topography effects on the detailed structure of clouds and surface ice deposits. Here, we present new numerical simulations of the annual water cycle performed at a resolution of 1° × 1° (∼ 60 km in latitude). The model includes the radiative effects of clouds, whose influence on the thermal structure and atmospheric dynamics is significant, thus we also examine simulations with inactive clouds to distinguish the direct impact of resolution on circulation and winds from the indirect impact of resolution via water ice clouds. To first order, we find that the high resolution does not dramatically change the behavior of the system, and that simulations performed at ∼ 200 km resolution capture well the behavior of the simulated water cycle and Mars climate. Nevertheless, a detailed comparison between high and low resolution simulations, with reference to observations, reveal several significant changes that impact our understanding of the water cycle active today on Mars. The key northern cap edge dynamics are affected by an increase in baroclinic wave strength, with a complication of northern summer dynamics. South polar frost deposition is modified, with a westward longitudinal shift, since southern dynamics are also influenced. Baroclinic wave mode transitions are observed. New transient phenomena appear, like spiral and streak clouds, already documented in the observations. Atmospheric circulation cells in the polar region exhibit a large variability and are fine structured, with slope winds. Most modeled phenomena affected by high resolution give a picture of a more turbulent planet, inducing further variability. This is challenging for long-period climate studies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liese, Eric; Zitney, Stephen E.

A multi-stage centrifugal compressor model is presented with emphasis on analyzing use of an exit flow coefficient vs. an inlet flow coefficient performance parameter to predict off-design conditions in the critical region of a supercritical carbon dioxide (CO 2) power cycle. A description of the performance parameters is given along with their implementation in a design model (number of stages, basic sizing, etc.) and a dynamic model (for use in transient studies). A design case is shown for two compressors, a bypass compressor and a main compressor, as defined in a process simulation of a 10 megawatt (MW) supercritical COmore » 2 recompression Brayton cycle. Simulation results are presented for a simple open cycle and closed cycle process with changes to the inlet temperature of the main compressor which operates near the CO 2 critical point. Results showed some difference in results using the exit vs. inlet flow coefficient correction, however, it was not significant for the range of conditions examined. Here, this paper also serves as a reference for future works, including a full process simulation of the 10 MW recompression Brayton cycle.« less

Effectiveness of a Combination of Cranberries, Lactobacillus rhamnosus, and Vitamin C for the Management of Recurrent Urinary Tract Infections in Women: Results of a Pilot Study.

PubMed

Montorsi, Francesco; Gandaglia, Giorgio; Salonia, Andrea; Briganti, Alberto; Mirone, Vincenzo

2016-12-01

Urinary tract infections (UTIs) are common in women and many patients with recurrent UTIs do not eradicate the condition albeit being treated with multiple courses of antibiotics. The use of nutritional supplements might reduce the risk of recurrent UTIs. However, the role of supplements taken as single agents appears to be limited. We hypothesized that a combination of cranberries, Lactobacillus rhamnosus, and vitamin C might produce a clinical benefit due to their additive or synergistic effects. We prospectively enrolled 42 consecutive women with recurrent UTIs treated with 120mg cranberries (minimum proanthocyanidin content: 32mg), 1 billion heat-killed L. rhamnosus SGL06, and 750mg vitamin C thrice daily for 20 consecutive d. Patients were advised to stop taking these supplements for 10 d and then to repeat the whole cycle three times. Patients were contacted three mo and six mo following the end of the administration of these supplements and evaluated with a semistructured interview and urinalysis. Responders were defined as the absence of symptoms and negative urinalysis or urine culture. Follow-up data were available for 36 patients. Overall, 26 (72.2%) and 22 patients (61.1%) were responders at the 3-mo and 6-month follow-up. No major side effects were recorded. The administration of cranberries, L. rhamnosus, and vitamin C might represent a safe and effective option in women with recurrent UTIs. We evaluated the effectiveness of cranberries, Lactobacillus rhamnosus, and vitamin C thrice daily for 20 consecutive d monthly for 3 mo for the management of recurrent urinary tract infections in women. Our results show that this approach might represent a safe and effective option. Copyright © 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Discrete Element Model for Simulations of Early-Life Thermal Fracturing Behaviors in Ceramic Nuclear Fuel Pellets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hai Huang; Ben Spencer; Jason Hales

2014-10-01

A discrete element Model (DEM) representation of coupled solid mechanics/fracturing and heat conduction processes has been developed and applied to explicitly simulate the random initiations and subsequent propagations of interacting thermal cracks in a ceramic nuclear fuel pellet during initial rise to power and during power cycles. The DEM model clearly predicts realistic early-life crack patterns including both radial cracks and circumferential cracks. Simulation results clearly demonstrate the formation of radial cracks during the initial power rise, and formation of circumferential cracks as the power is ramped down. In these simulations, additional early-life power cycles do not lead to themore » formation of new thermal cracks. They do, however clearly indicate changes in the apertures of thermal cracks during later power cycles due to thermal expansion and shrinkage. The number of radial cracks increases with increasing power, which is consistent with the experimental observations.« less

S.A.M., the Italian Martian Simulation Chamber

NASA Astrophysics Data System (ADS)

Galletta, G.; Ferri, F.; Fanti, G.; D'Alessandro, M.; Bertoloni, G.; Pavarin, D.; Bettanini, C.; Cozza, P.; Pretto, P.; Bianchini, G.; Debei, S.

2006-12-01

The Martian Environment Simulator (SAM “Simulatore di Ambiente Marziano”) is a interdisciplinary project of Astrobiology done at University of Padua. The research is aimed to the study of the survival of the microorganisms exposed to the “extreme” planetary environment. The facility has been designed in order to simulate Mars’ environmental conditions in terms of atmospheric pressure, temperature cycles and UV radiation dose. The bacterial cells, contained into dedicated capsules, will be exposed to thermal cycles simulating diurnal and seasonal Martian cycles. The metabolism of the different biological samples will be analysed at different phases of the experiment, to study their survival and eventual activity of protein synthesis (mortality, mutations and capability of DNA reparing). We describe the experimental facility and provide the perspectives of the biological experiments we will perform in order to provide hints on the possibility of life on Mars either autochthonous or imported from Earth.

Verifying Safeguards Declarations with INDEPTH: A Sensitivity Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grogan, Brandon R; Richards, Scott

2017-01-01

A series of ORIGEN calculations were used to simulate the irradiation and decay of a number of spent fuel assemblies. These simulations focused on variations in the irradiation history that achieved the same terminal burnup through a different set of cycle histories. Simulated NDA measurements were generated for each test case from the ORIGEN data. These simulated measurement types included relative gammas, absolute gammas, absolute gammas plus neutrons, and concentrations of a set of six isotopes commonly measured by NDA. The INDEPTH code was used to reconstruct the initial enrichment, cooling time, and burnup for each irradiation using each simulatedmore » measurement type. The results were then compared to the initial ORIGEN inputs to quantify the size of the errors induced by the variations in cycle histories. Errors were compared based on the underlying changes to the cycle history, as well as the data types used for the reconstructions.« less

Quasi-Biennial Oscillation and Solar Cycle Influences over the Winter Arctic Simulated by the WACCM4 Model

NASA Astrophysics Data System (ADS)

Li, K. F.; Limpasuvan, T. L.; Limpasuvan, V.; Tung, K. K.; Yung, Y. L.

2017-12-01

Observations show that the quasi-biennial oscillation (QBO) and the 11-year solar cycle perturb the polar vortex via planetary wave convergence at high latitudes, a mechanism first proposed by Holton and Tan in 1980. Their perturbations lead to increases of stratospheric sudden warming events, and hence observable increases in temperature and ozone abundance in the polar vortex, during the easterly phase of QBO and the solar maximum. Here we simulate the changes in the polar atmosphere using the Whole Atmosphere Community Climate Model 4 (WACCM4) with the prescribed QBO and 11-year solar cycle forcing. The simulation is diagnosed in four groups: westerly QBO phase and solar minimum, westerly QBO phase and solar maximum, easterly QBO phase and solar minimum, and easterly QBO phase and solar maximum. The simulated changes in temperature and ozone are compared with satellite observations.

Effect of Temperature Cycling and Exposure to Extreme Temperatures on Reliability of Solid Tantalum Capacitors

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander

2007-01-01

In this work, results of multiple temperature cycling (TC) (up to 1,000 cycles) of different types of solid tantalum capacitors are analyzed and reported. Deformation of chip tantalum during temperature variations simulating reflow soldering conditions was measured to evaluate the possibility of the pop-corning effect in the parts. To simulate the effect of short-time exposures to solder reflow temperatures on the reliability of tantalum capacitors, several part types were subjected to multiple cycles (up to 100) between room temperature and 240 C with periodical measurements of electrical characteristics of the parts. Mechanisms of degradation caused by temperature cycling and exposure to high temperatures, and the requirements of MIL-PRF-55365 for assessment of the resistance of the parts to soldering heat are discussed.

Recurrent antecedent hypoglycemia alters neuronal oxidative metabolism in vivo.

PubMed

Jiang, Lihong; Herzog, Raimund I; Mason, Graeme F; de Graaf, Robin A; Rothman, Douglas L; Sherwin, Robert S; Behar, Kevin L

2009-06-01

The objective of this study was to characterize the changes in brain metabolism caused by antecedent recurrent hypoglycemia under euglycemic and hypoglycemic conditions in a rat model and to test the hypothesis that recurrent hypoglycemia changes the brain's capacity to utilize different energy substrates. Rats exposed to recurrent insulin-induced hypoglycemia for 3 days (3dRH rats) and untreated controls were subject to the following protocols: [2-(13)C]acetate infusion under euglycemic conditions (n = 8), [1-(13)C]glucose and unlabeled acetate coinfusion under euglycemic conditions (n = 8), and [2-(13)C]acetate infusion during a hyperinsulinemic-hypoglycemic clamp (n = 8). In vivo nuclear magnetic resonance spectroscopy was used to monitor the rise of(13)C-labeling in brain metabolites for the calculation of brain metabolic fluxes using a neuron-astrocyte model. At euglycemia, antecedent recurrent hypoglycemia increased whole-brain glucose metabolism by 43 +/- 4% (P < 0.01 vs. controls), largely due to higher glucose utilization in neurons. Although acetate metabolism remained the same, control and 3dRH animals showed a distinctly different response to acute hypoglycemia: controls decreased pyruvate dehydrogenase (PDH) flux in astrocytes by 64 +/- 20% (P = 0.01), whereas it increased by 37 +/- 3% in neurons (P = 0.01). The 3dRH animals decreased PDH flux in both compartments (-75 +/- 20% in astrocytes, P < 0.001, and -36 +/- 4% in neurons, P = 0.005). Thus, acute hypoglycemia reduced total brain tricarboxylic acid cycle activity in 3dRH animals (-37 +/- 4%, P = 0.001), but not in controls. Our findings suggest that after antecedent hypoglycemia, glucose utilization is increased at euglycemia and decreased after acute hypoglycemia, which was not the case in controls. These findings may help to identify better methods of preserving brain function and reducing injury during acute hypoglycemia.

Impact of hospital type and treatment on long-term survival among patients with FIGO Stage IIIC epithelial ovarian cancer: follow-up through two recurrences and three treatment lines in search for predictors for survival.

PubMed

Szczesny, W; Vistad, I; Kaern, J; Nakling, J; Tropé, C; Paulsen, T

2016-01-01

The purpose of this study was to investigate the impact of hospital type determined at primary treatment and find possible predictors of survival in a cohort of patients with advanced epithelial ovarian cancer (EOC) who recurred twice and received three lines of treatment during eight-year follow-up. Using the Norwegian Cancer Registry, the authors identified 174 women with FIGO Stage IIIC EOC diagnosed in 2002. First-line treatment consisted of up-front debulking surgery and chemotherapy, received in either a teaching hospital (TH, n = 84) or a non-teaching hospital (NTH, n = 90). After recurrence all patients in Norway are equally consulted at TH. Survival determined for three time intervals (TI): TI-1, from end date of first-line treatment to first recurrence or death, TI-2, from beginning of second-line treatment until second recurrence or death, and TI-3, from beginning of third-line treatment to death or end of follow-up. Extensive surgery carried out in TH followed by at least six cycles of platinol-taxan chemotherapy resulted in longer survival in the TH group during TI-1. Altogether, the majority of those who receive treatment for recurrences were primary better debulked with following platinol-taxane chemotherapy. Survival in TI-2 was influenced by platinol-sensitivity. During TI-3 the majority (96%) had good performance status and their mean age at primary diagnosis at either hospital type was 57 years. Extensive primary surgery at TH, platinol sensitivity, age, and performance status were predictors of survival in this cohort.

Fixed recurrence and slip models better predict earthquake behavior than the time- and slip-predictable models 1: repeating earthquakes

USGS Publications Warehouse

Rubinstein, Justin L.; Ellsworth, William L.; Chen, Kate Huihsuan; Uchida, Naoki

2012-01-01

The behavior of individual events in repeating earthquake sequences in California, Taiwan and Japan is better predicted by a model with fixed inter-event time or fixed slip than it is by the time- and slip-predictable models for earthquake occurrence. Given that repeating earthquakes are highly regular in both inter-event time and seismic moment, the time- and slip-predictable models seem ideally suited to explain their behavior. Taken together with evidence from the companion manuscript that shows similar results for laboratory experiments we conclude that the short-term predictions of the time- and slip-predictable models should be rejected in favor of earthquake models that assume either fixed slip or fixed recurrence interval. This implies that the elastic rebound model underlying the time- and slip-predictable models offers no additional value in describing earthquake behavior in an event-to-event sense, but its value in a long-term sense cannot be determined. These models likely fail because they rely on assumptions that oversimplify the earthquake cycle. We note that the time and slip of these events is predicted quite well by fixed slip and fixed recurrence models, so in some sense they are time- and slip-predictable. While fixed recurrence and slip models better predict repeating earthquake behavior than the time- and slip-predictable models, we observe a correlation between slip and the preceding recurrence time for many repeating earthquake sequences in Parkfield, California. This correlation is not found in other regions, and the sequences with the correlative slip-predictable behavior are not distinguishable from nearby earthquake sequences that do not exhibit this behavior.

PubMed Central

Gaffuri, M.; Rossi, V.; Pignataro, L

2017-01-01

SUMMARY It has been suggested that a conservative trans-oral approach to proximal and hilo-parenchymal submandibular stones (HPSMS) is a valid alternative to the more frequently used sialadenectomy. The aim of this study was to evaluate the surgical, ultrasonographic and patients' subjective outcomes of results of the trans-oral removal of HPSMS. Between January 2003 and September 2015, sialendoscope-assisted trans-oral surgery was used to remove symptomatic, large (> 7 mm), fixed and palpable HPSMS from 479 patients under general anaesthesia. All patients were followed clinically and ultrasonographically to investigate symptom relief and recurrence of stones, and were telephonically interviewed to assess saliva-related subjective outcomes with a questionnaire. Stones were successfully removed from 472 patients (98.5%); the seven failures (1.5%) concerned pure parenchymal stones. One year after the procedure, 408 patients (85.1%) were symptom free, 59 (12.3%) had recurrent obstructive symptoms and 12 (2.6%) had recurrent infections. Of the 54 patients who developed a recurrent stone (11.2%), 52 underwent a second procedure: 29 interventional sialendoscopies, two sialendoscope-assisted intra-corporeal pneumatic lithotripsy, eight secondary transoral surgery to remove residual stones, six a cycle of extra-corporeal lithotripsy and seven submandibular sialadenectomy. Most patients (75.2%) reported mild surgery-related pain. The symptoms of 454 patients (94.8%) improved after adjunctive treatment and, at the end of follow-up, the affected gland was preserved in 98.5% of patients. A sialendoscope-assisted trans-oral removal of large HPSMS is a safe, effective, conservative surgical procedure, and functional preservation of the main duct and parenchyma of the obstructed gland allows sialendoscopic access through the natural ostium in case of recurrence. Combining a trans-oral approach with other minimally invasive, conservative procedures ensures symptomatic relief and salivary duct system clearance in the majority of patients. PMID:28516974

Translations on Eastern Europe Scientific Affairs No. 541.

DTIC Science & Technology

1977-04-08

studies of seismic risk and zoning were also presented at two conferences, one held in Bucharest in May 197^, and the other in Skopje in April 1975...That is where the experts and specialists presented the results of their research in seismic zoning, recurrence periods for earthquakes...Urancei region around the year 2D8D. This forecast is based on the theory of extreme values and seismic cycles. At the present time, other

Planetary Defense: Eliminating the Giggle Factor

DTIC Science & Technology

2000-01-01

the coast of the Yucatan Peninsula, and is today credited with ridding the world of the dinosaur menace.1 Since the discovery of these and other...million years, with a less distinct recurrence of larger objects.2 The periodicity of 10 km-size asteroid strikes correlates reasonably well...within the error range of geologic dating) with major global extinction events (as many as ten) recurring on a 26 million year cycle dating back 260

Uranium oxide fuel cycle analysis in VVER-1000 with VISTA simulation code

NASA Astrophysics Data System (ADS)

Mirekhtiary, Seyedeh Fatemeh; Abbasi, Akbar

2018-02-01

The VVER-1000 Nuclear power plant generates about 20-25 tons of spent fuel per year. In this research, the fuel transmutation of Uranium Oxide (UOX) fuel was calculated by using of nuclear fuel cycle simulation system (VISTA) code. In this simulation, we evaluated the back end components fuel cycle. The back end component calculations are Spent Fuel (SF), Actinide Inventory (AI) and Fission Product (FP) radioisotopes. The SF, AI and FP values were obtained 23.792178 ton/y, 22.811139 ton/y, 0.981039 ton/y, respectively. The obtained value of spent fuel, major actinide, and minor actinide and fission products were 23.8 ton/year, 22.795 ton/year, 0.024 ton/year and 0.981 ton/year, respectively.

Simulated Effect of Carbon Cycle Feedback on Climate Response to Solar Geoengineering

NASA Astrophysics Data System (ADS)

Cao, Long; Jiang, Jiu

2017-12-01

Most modeling studies investigate climate effects of solar geoengineering under prescribed atmospheric CO2, thereby neglecting potential climate feedbacks from the carbon cycle. Here we use an Earth system model to investigate interactive feedbacks between solar geoengineering, global carbon cycle, and climate change. We design idealized sunshade geoengineering simulations to prevent global warming from exceeding 2°C above preindustrial under a CO2 emission scenario with emission mitigation starting from middle of century. By year 2100, solar geoengineering reduces the burden of atmospheric CO2 by 47 PgC with enhanced carbon storage in the terrestrial biosphere. As a result of reduced atmospheric CO2, consideration of the carbon cycle feedback reduces required insolation reduction in 2100 from 2.0 to 1.7 W m-2. With higher climate sensitivity the effect from carbon cycle feedback becomes more important. Our study demonstrates the importance of carbon cycle feedback in climate response to solar geoengineering.

Dedifferentiated Liposarcoma: Updates on Morphology, Genetics, and Therapeutic Strategies.

PubMed

Thway, Khin; Jones, Robin L; Noujaim, Jonathan; Zaidi, Shane; Miah, Aisha B; Fisher, Cyril

2016-01-01

Well-differentiated liposarcoma (WDL) and dedifferentiated liposarcoma (DDL) form the largest subgroup of liposarcomas, and represent a morphologic and behavioral spectrum of 1 disease entity, which arises typically in middle to late adult life, most frequently within the retroperitoneum or extremities. DDL is defined as nonlipogenic sarcoma that is juxtaposed to WDL, occurs as a recurrence of WDL or which can arise de novo, and typically has the appearance of undifferentiated pleomorphic or spindle cell sarcoma. DDL have a propensity for local recurrence, whereas distant metastasis is rarer, and behavior is related to anatomic site, with retroperitoneal neoplasms showing a significantly worse prognosis. Surgical resection remains the mainstay of treatment, and medical options for patients with aggressive recurrent or metastatic disease are limited. DDL share similar genetic abnormalities to WDL, with high-level amplifications of chromosome 12q14-15, including the MDM2 and CDK4 cell cycle oncogenes, and DDL harbor additional genetic changes, particularly coamplifications of 6q23 and 1p32. Novel therapies targeted at the gene products of chromosome 12 are being tested in clinical trials. We review the pathology and genetics of DDL, discussing morphologic patterns, immunohistochemical and genetic findings, the differential diagnosis, and future therapeutic strategies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dósa, M.; Erdős, G., E-mail: dosa.melinda@wigner.mta.hu

Open magnetic flux in the heliosphere is determined from the radial component of the magnetic field vector measured onboard interplanetary space probes. Previous Ulysses research has shown remarkable independence of the flux density from heliographic latitude, explained by super-radial expansion of plasma. Here we are investigating whether any longitudinal variation exists in the 50 year long OMNI magnetic data set. The heliographic longitude of origin of the plasma package was determined by applying a correction according to the solar wind travel time. Significant recurrent enhancements of the magnetic flux density were observed throughout solar cycle 23, lasting for several years.more » Similar, long-lasting recurring features were observed in the solar wind velocity, temperature and the deviation angle of the solar wind velocity vector from the radial direction. Each of the recurrent features has a recurrence period slightly differing from the Carrington rotation rate, although they show a common trend in time. Examining the coronal temperature data of ACE leads to the possible explanation that these long-term structures are caused by slow–fast solar wind interaction regions. A comparison with MESSENGER data measured at 0.5 au shows that these longitudinal magnetic modulations do not exist closer to the Sun, but are the result of propagation.« less

Aspiration and ethanol sclerotherapy to treat recurrent ovarian endometriomas prior to in vitro fertilization - a pilot study.

PubMed

André, Gustavo Mendonça; Vilarino, Fábia Lima; Christofolini, Denise Maria; Bianco, Bianca; Barbosa, Caio Parente

2011-12-01

To describe the evolution of controlled ovarian hyperstimulation in women with recurrent ovarian endometriomas treated with sclerotherapy. Twenty-one patients with a laparoscopic diagnosis of stage III or IV endometriosis who had an endometrioma larger than 3 cm before ovarian hyperstimulation for in vitro fertilization were included in the study. After using a GnRH agonist analog for at least 20 days, the cysts were punctured using ultrasound guidance and subsequent ethanol sclerotherapy was performed. Then, the patients were stimulated with 100 or 200 U/day of recombinant follicle stimulating hormone, varying the dose according to the patient's age or history of a previous unilateral oophorectomy. The ovarian cysts had an average diameter of 4.7 ± 1.4 cm and did not recur after aspiration during the ovulation induction. Oocyte extraction occurred after 11 days of hyperstimulation, with 3.95 ± 3.30 oocytes obtained per cycle, on average. Embryo transfer occurred in 71.4% (15/21) of patients, and the pregnancy rate after transfer was 20% (3/15). Aspiration followed by ethanol sclerotherapy prior to in vitro fertilization can be an option for patients who desire a pregnancy and have recurrent endometriomas.

Global transcriptome analysis of formalin-fixed prostate cancer specimens identifies biomarkers of disease recurrence.

PubMed

Long, Qi; Xu, Jianpeng; Osunkoya, Adeboye O; Sannigrahi, Soma; Johnson, Brent A; Zhou, Wei; Gillespie, Theresa; Park, Jong Y; Nam, Robert K; Sugar, Linda; Stanimirovic, Aleksandra; Seth, Arun K; Petros, John A; Moreno, Carlos S

2014-06-15

Prostate cancer remains the second leading cause of cancer death in American men and there is an unmet need for biomarkers to identify patients with aggressive disease. In an effort to identify biomarkers of recurrence, we performed global RNA sequencing on 106 formalin-fixed, paraffin-embedded prostatectomy samples from 100 patients at three independent sites, defining a 24-gene signature panel. The 24 genes in this panel function in cell-cycle progression, angiogenesis, hypoxia, apoptosis, PI3K signaling, steroid metabolism, translation, chromatin modification, and transcription. Sixteen genes have been associated with cancer, with five specifically associated with prostate cancer (BTG2, IGFBP3, SIRT1, MXI1, and FDPS). Validation was performed on an independent publicly available dataset of 140 patients, where the new signature panel outperformed markers published previously in terms of predicting biochemical recurrence. Our work also identified differences in gene expression between Gleason pattern 4 + 3 and 3 + 4 tumors, including several genes involved in the epithelial-to-mesenchymal transition and developmental pathways. Overall, this study defines a novel biomarker panel that has the potential to improve the clinical management of prostate cancer. ©2014 American Association for Cancer Research.

A Self-consistent Model for a Full Cycle of Recurrent Novae—Wind Mass-loss Rate and X-Ray Luminosity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kato, Mariko; Saio, Hideyuki; Hachisu, Izumi, E-mail: mariko.kato@hc.st.keio.ac.jp

2017-04-01

An unexpectedly slow evolution in the pre-optical-maximum phase was suggested in the very short recurrence period of nova M31N 2008-12a. To obtain reasonable nova light curves we have improved our calculation method by consistently combining optically thick wind solutions of hydrogen-rich envelopes with white dwarf (WD) structures calculated by a Henyey-type evolution code. The wind mass-loss rate is properly determined with high accuracy. We have calculated light curve models for 1.2 M {sub ⊙} and 1.38 M {sub ⊙} WDs with mass accretion rates corresponding to recurrence periods of 10 yr and 1 yr, respectively. The outburst lasts 590/29 days,more » in which the pre-optical-maximum phase is 82/16 days, for 1.2/1.38 M {sub ⊙}, respectively. Optically thick winds start at the end of the X-ray flash and cease at the beginning of the supersoft X-ray phase. We also present supersoft X-ray light curves including a prompt X-ray flash and later supersoft X-ray phase.« less

C4MIP - The Coupled Climate-Carbon Cycle Model Intercomparison Project: experimental protocol for CMIP6

NASA Astrophysics Data System (ADS)

Jones, Chris D.; Arora, Vivek; Friedlingstein, Pierre; Bopp, Laurent; Brovkin, Victor; Dunne, John; Graven, Heather; Hoffman, Forrest; Ilyina, Tatiana; John, Jasmin G.; Jung, Martin; Kawamiya, Michio; Koven, Charlie; Pongratz, Julia; Raddatz, Thomas; Randerson, James T.; Zaehle, Sönke

2016-08-01

Coordinated experimental design and implementation has become a cornerstone of global climate modelling. Model Intercomparison Projects (MIPs) enable systematic and robust analysis of results across many models, by reducing the influence of ad hoc differences in model set-up or experimental boundary conditions. As it enters its 6th phase, the Coupled Model Intercomparison Project (CMIP6) has grown significantly in scope with the design and documentation of individual simulations delegated to individual climate science communities. The Coupled Climate-Carbon Cycle Model Intercomparison Project (C4MIP) takes responsibility for design, documentation, and analysis of carbon cycle feedbacks and interactions in climate simulations. These feedbacks are potentially large and play a leading-order contribution in determining the atmospheric composition in response to human emissions of CO2 and in the setting of emissions targets to stabilize climate or avoid dangerous climate change. For over a decade, C4MIP has coordinated coupled climate-carbon cycle simulations, and in this paper we describe the C4MIP simulations that will be formally part of CMIP6. While the climate-carbon cycle community has created this experimental design, the simulations also fit within the wider CMIP activity, conform to some common standards including documentation and diagnostic requests, and are designed to complement the CMIP core experiments known as the Diagnostic, Evaluation and Characterization of Klima (DECK). C4MIP has three key strands of scientific motivation and the requested simulations are designed to satisfy their needs: (1) pre-industrial and historical simulations (formally part of the common set of CMIP6 experiments) to enable model evaluation, (2) idealized coupled and partially coupled simulations with 1 % per year increases in CO2 to enable diagnosis of feedback strength and its components, (3) future scenario simulations to project how the Earth system will respond to anthropogenic activity over the 21st century and beyond. This paper documents in detail these simulations, explains their rationale and planned analysis, and describes how to set up and run the simulations. Particular attention is paid to boundary conditions, input data, and requested output diagnostics. It is important that modelling groups participating in C4MIP adhere as closely as possible to this experimental design.

C4MIP – The Coupled Climate–Carbon Cycle Model Intercomparison Project: Experimental protocol for CMIP6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, Chris D.; Arora, Vivek; Friedlingstein, Pierre

Coordinated experimental design and implementation has become a cornerstone of global climate modelling. Model Intercomparison Projects (MIPs) enable systematic and robust analysis of results across many models, by reducing the influence of ad hoc differences in model set-up or experimental boundary conditions. As it enters its 6th phase, the Coupled Model Intercomparison Project (CMIP6) has grown significantly in scope with the design and documentation of individual simulations delegated to individual climate science communities. The Coupled Climate–Carbon Cycle Model Intercomparison Project (C4MIP) takes responsibility for design, documentation, and analysis of carbon cycle feedbacks and interactions in climate simulations. These feedbacks aremore » potentially large and play a leading-order contribution in determining the atmospheric composition in response to human emissions of CO 2 and in the setting of emissions targets to stabilize climate or avoid dangerous climate change. For over a decade, C4MIP has coordinated coupled climate–carbon cycle simulations, and in this paper we describe the C4MIP simulations that will be formally part of CMIP6. While the climate–carbon cycle community has created this experimental design, the simulations also fit within the wider CMIP activity, conform to some common standards including documentation and diagnostic requests, and are designed to complement the CMIP core experiments known as the Diagnostic, Evaluation and Characterization of Klima (DECK). C4MIP has three key strands of scientific motivation and the requested simulations are designed to satisfy their needs: (1) pre-industrial and historical simulations (formally part of the common set of CMIP6 experiments) to enable model evaluation, (2) idealized coupled and partially coupled simulations with 1 % per year increases in CO 2 to enable diagnosis of feedback strength and its components, (3) future scenario simulations to project how the Earth system will respond to anthropogenic activity over the 21st century and beyond. This study documents in detail these simulations, explains their rationale and planned analysis, and describes how to set up and run the simulations. Particular attention is paid to boundary conditions, input data, and requested output diagnostics. It is important that modelling groups participating in C4MIP adhere as closely as possible to this experimental design.« less

C4MIP – The Coupled Climate–Carbon Cycle Model Intercomparison Project: Experimental protocol for CMIP6

DOE PAGES

Jones, Chris D.; Arora, Vivek; Friedlingstein, Pierre; ...

2016-08-25

Coordinated experimental design and implementation has become a cornerstone of global climate modelling. Model Intercomparison Projects (MIPs) enable systematic and robust analysis of results across many models, by reducing the influence of ad hoc differences in model set-up or experimental boundary conditions. As it enters its 6th phase, the Coupled Model Intercomparison Project (CMIP6) has grown significantly in scope with the design and documentation of individual simulations delegated to individual climate science communities. The Coupled Climate–Carbon Cycle Model Intercomparison Project (C4MIP) takes responsibility for design, documentation, and analysis of carbon cycle feedbacks and interactions in climate simulations. These feedbacks aremore » potentially large and play a leading-order contribution in determining the atmospheric composition in response to human emissions of CO 2 and in the setting of emissions targets to stabilize climate or avoid dangerous climate change. For over a decade, C4MIP has coordinated coupled climate–carbon cycle simulations, and in this paper we describe the C4MIP simulations that will be formally part of CMIP6. While the climate–carbon cycle community has created this experimental design, the simulations also fit within the wider CMIP activity, conform to some common standards including documentation and diagnostic requests, and are designed to complement the CMIP core experiments known as the Diagnostic, Evaluation and Characterization of Klima (DECK). C4MIP has three key strands of scientific motivation and the requested simulations are designed to satisfy their needs: (1) pre-industrial and historical simulations (formally part of the common set of CMIP6 experiments) to enable model evaluation, (2) idealized coupled and partially coupled simulations with 1 % per year increases in CO 2 to enable diagnosis of feedback strength and its components, (3) future scenario simulations to project how the Earth system will respond to anthropogenic activity over the 21st century and beyond. This study documents in detail these simulations, explains their rationale and planned analysis, and describes how to set up and run the simulations. Particular attention is paid to boundary conditions, input data, and requested output diagnostics. It is important that modelling groups participating in C4MIP adhere as closely as possible to this experimental design.« less

The exponential-Poisson model for recurrent event data: an application to a set of data on malaria in Brazil.

PubMed

Macera, Márcia A C; Louzada, Francisco; Cancho, Vicente G; Fontes, Cor J F

2015-03-01

In this paper, we introduce a new model for recurrent event data characterized by a baseline rate function fully parametric, which is based on the exponential-Poisson distribution. The model arises from a latent competing risk scenario, in the sense that there is no information about which cause was responsible for the event occurrence. Then, the time of each recurrence is given by the minimum lifetime value among all latent causes. The new model has a particular case, which is the classical homogeneous Poisson process. The properties of the proposed model are discussed, including its hazard rate function, survival function, and ordinary moments. The inferential procedure is based on the maximum likelihood approach. We consider an important issue of model selection between the proposed model and its particular case by the likelihood ratio test and score test. Goodness of fit of the recurrent event models is assessed using Cox-Snell residuals. A simulation study evaluates the performance of the estimation procedure in the presence of a small and moderate sample sizes. Applications on two real data sets are provided to illustrate the proposed methodology. One of them, first analyzed by our team of researchers, considers the data concerning the recurrence of malaria, which is an infectious disease caused by a protozoan parasite that infects red blood cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Recurrent Case for the Renshaw Cell

PubMed Central

Bhumbra, Gardave S.; Bannatyne, B. Anne; Watanabe, Masahiko; Todd, Andrew J.

2014-01-01

Although Renshaw cells (RCs) were discovered over half a century ago, their precise role in recurrent inhibition and ability to modulate motoneuron excitability have yet to be established. Indirect measurements of recurrent inhibition have suggested only a weak modulatory effect but are limited by the lack of observed motoneuron responses to inputs from single RCs. Here we present dual recordings between connected RC–motoneuron pairs, performed on mouse spinal cord. Motoneuron responses demonstrated that Renshaw synapses elicit large inhibitory conductances and show short-term potentiation. Anatomical reconstruction, combined with a novel method of quantal analysis, showed that the strong inhibitory input from RCs results from the large number of synaptic contacts that they make onto individual motoneurons. We used the NEURON simulation environment to construct realistic electrotonic models, which showed that inhibitory conductances from Renshaw inputs exert considerable shunting effects in motoneurons and reduce the frequency of spikes generated by excitatory inputs. This was confirmed experimentally by showing that excitation of a single RC or selective activation of the recurrent inhibitory pathway to generate equivalent inhibitory conductances both suppress motoneuron firing. We conclude that recurrent inhibition is remarkably effective, in that a single action potential from one RC is sufficient to silence a motoneuron. Although our results may differ from previous indirect observations, they underline a need for a reevaluation of the role that RCs perform in one of the first neuronal circuits to be discovered. PMID:25232126

Earthquakes: Recurrence and Interoccurrence Times

NASA Astrophysics Data System (ADS)

Abaimov, S. G.; Turcotte, D. L.; Shcherbakov, R.; Rundle, J. B.; Yakovlev, G.; Goltz, C.; Newman, W. I.

2008-04-01

The purpose of this paper is to discuss the statistical distributions of recurrence times of earthquakes. Recurrence times are the time intervals between successive earthquakes at a specified location on a specified fault. Although a number of statistical distributions have been proposed for recurrence times, we argue in favor of the Weibull distribution. The Weibull distribution is the only distribution that has a scale-invariant hazard function. We consider three sets of characteristic earthquakes on the San Andreas fault: (1) The Parkfield earthquakes, (2) the sequence of earthquakes identified by paleoseismic studies at the Wrightwood site, and (3) an example of a sequence of micro-repeating earthquakes at a site near San Juan Bautista. In each case we make a comparison with the applicable Weibull distribution. The number of earthquakes in each of these sequences is too small to make definitive conclusions. To overcome this difficulty we consider a sequence of earthquakes obtained from a one million year “Virtual California” simulation of San Andreas earthquakes. Very good agreement with a Weibull distribution is found. We also obtain recurrence statistics for two other model studies. The first is a modified forest-fire model and the second is a slider-block model. In both cases good agreements with Weibull distributions are obtained. Our conclusion is that the Weibull distribution is the preferred distribution for estimating the risk of future earthquakes on the San Andreas fault and elsewhere.

Supra-recommendation Treatment of Super-refractory Status Epilepticus.

PubMed

Vyas, Devashish Dhiren; Dash, Gopal Krishna

2016-06-01

A 28-year old female was admitted with recurrent seizures following 2 days of febrile illness, after which she developed status epilepticus. Midazolam and later thiopentone infusions were started after failure of regular intravenous antiepileptics. Burst suppression was achieved at doses of 3 mg/kg/hr for midazolam and 6 mg/kg/hr of thiopentone. Adjunctive medications included methylprednisolone, intravenous immunoglobulin and acyclovir. Imaging and biochemical parameters were normal. She required 3 cycles of midazolam and 2 cycles of thiopentone for complete cessation of seizures. She recovered with mild attentional and recent memory deficits on follow up. Treatment of super-refractory status epilepticus requires individualized regimens and may need doses beyond conventional limits. To the best of our knowledge, there is no such reported case from India.

Cycle analysis of MCFC/gas turbine system

NASA Astrophysics Data System (ADS)

Musa, Abdullatif; Alaktiwi, Abdulsalam; Talbi, Mosbah

2017-11-01

High temperature fuel cells such as the solid oxide fuel cell (SOFC) and the molten carbonate fuel cell (MCFC) are considered extremely suitable for electrical power plant application. The molten carbonate fuel cell (MCFC) performances is evaluated using validated model for the internally reformed (IR) fuel cell. This model is integrated in Aspen Plus™. Therefore, several MCFC/Gas Turbine systems are introduced and investigated. One of this a new cycle is called a heat recovery (HR) cycle. In the HR cycle, a regenerator is used to preheat water by outlet air compressor. So the waste heat of the outlet air compressor and the exhaust gases of turbine are recovered and used to produce steam. This steam is injected in the gas turbine, resulting in a high specific power and a high thermal efficiency. The cycles are simulated in order to evaluate and compare their performances. Moreover, the effects of an important parameters such as the ambient air temperature on the cycle performance are evaluated. The simulation results show that the HR cycle has high efficiency.

Association of increased S100A8 serum protein with early pregnancy loss.

PubMed

Nair, Rohini R; Khanna, Anuradha; Singh, Kiran

2015-02-01

The contribution of systemic S100A8 protein in menstrual cycle, pregnancy, and early pregnancy loss (EPL) is not known. Altered expression of S100A8 in maternal decidua is associated with recurrent early pregnancy loss. The objective of this study was to investigate the systemic level of S100A8 in different phases of menstrual cycle, different trimester of pregnancy, and in EPL. Level of S100A8 was investigated in serum samples of the subjects through enzyme-linked immunosorbent assay (ELISA). S100A8 levels were elevated during proliferative phase of menstrual cycle. We found no statistical difference in S100A8 level in different trimester of pregnancy. S100A8 level was found to be significantly elevated in patients with EPL. This is the first study evaluating the systemic level of S100A8 predicting its role during menstrual cycle and pregnancy. It opens a new perspective in which S100A8 can be used as a prognostic marker for EPL. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Biotribological evaluation of artificial disc arthroplasty devices: influence of loading and kinematic patterns during in vitro wear simulation.

PubMed

Grupp, Thomas M; Yue, James J; Garcia, Rolando; Basson, Janet; Schwiesau, Jens; Fritz, Bernhard; Blömer, Wilhelm

2009-01-01

Wear simulation is an essential pre-clinical method to predict the mid- and long-term clinical wear behavior of newly introduced devices for total disc arthroplasty. The main requirement of a suitable method for spinal wear simulation has to be the ability to distinguish between design concepts and allow for a direct comparison of predicate devices. The objective of our study was to investigate the influence of loading and kinematic patterns based on two different protocols for spinal wear simulation (ISO/FDIS 18192-1 (2006) and ASTM F2423-05). In vitro wear simulation was performed with six activ L lumbar artificial disc devices (Aesculap Tuttlingen, Germany). The applied kinematic pattern of movement was multidirectional for ISO (elliptic track) and unidirectional with a curvilinear shape for ASTM. Testing was done for 10 million cycles in the ISO loading mode and afterwards with the same specimens for 5 million cycles according to the ASTM protocol with a customized six-station servohydraulic spinal wear simulator (EndoLab Thansau, Germany). Gravimetrical and geometrical wear assessment, a slide track analysis correlated to an optical surface characterization, and an estimation of particle size and morphology were performed. The gravimetric wear rate for the first 10 million cycles was ISO(initial) = 2.7 +/- 0.3 mg/million cycles. During the ASTM test period (10-15 million cycles) a gravimetric wear rate of 0.14 +/- 0.06 mg/million cycles was estimated. The wear rates between the ISO and ASTM driven simulations differ substantially (approximately 20-fold) and statistical analysis demonstrates a significant difference (p < 0.001) between the test groups. The main explanation of divergency between ISO and ASTM driven wear simulations is the multidirectional pattern of movement described in the ISO document resulting in a cross-shear stress on the polyethylene material. Due to previous retrieval observations, it seems to be very unlikely that a lumbar artificial disc is loaded with a linear wear path.Testing according to ASTM F2423-05 with pure unidirectional motion does not reflect the kinematics of TDA patients' daily activities. Based on our findings it seems to be more reliable to predict the clinical wear behavior of an artificial disc replacement using the ISO/FDIS 18192-1 method.

Biotribological evaluation of artificial disc arthroplasty devices: influence of loading and kinematic patterns during in vitro wear simulation

PubMed Central

Yue, James J.; Garcia, Rolando; Basson, Janet; Schwiesau, Jens; Fritz, Bernhard; Blömer, Wilhelm

2008-01-01

Wear simulation is an essential pre-clinical method to predict the mid- and long-term clinical wear behavior of newly introduced devices for total disc arthroplasty. The main requirement of a suitable method for spinal wear simulation has to be the ability to distinguish between design concepts and allow for a direct comparison of predicate devices. The objective of our study was to investigate the influence of loading and kinematic patterns based on two different protocols for spinal wear simulation (ISO/FDIS 18192-1 (2006) and ASTM F2423-05). In vitro wear simulation was performed with six activ® L lumbar artificial disc devices (Aesculap Tuttlingen, Germany). The applied kinematic pattern of movement was multidirectional for ISO (elliptic track) and unidirectional with a curvilinear shape for ASTM. Testing was done for 10 million cycles in the ISO loading mode and afterwards with the same specimens for 5 million cycles according to the ASTM protocol with a customized six-station servohydraulic spinal wear simulator (EndoLab Thansau, Germany). Gravimetrical and geometrical wear assessment, a slide track analysis correlated to an optical surface characterization, and an estimation of particle size and morphology were performed. The gravimetric wear rate for the first 10 million cycles was ISOinitial = 2.7 ± 0.3 mg/million cycles. During the ASTM test period (10–15 million cycles) a gravimetric wear rate of 0.14 ± 0.06 mg/million cycles was estimated. The wear rates between the ISO and ASTM driven simulations differ substantially (approximately 20-fold) and statistical analysis demonstrates a significant difference (p < 0.001) between the test groups. The main explanation of divergency between ISO and ASTM driven wear simulations is the multidirectional pattern of movement described in the ISO document resulting in a cross-shear stress on the polyethylene material. Due to previous retrieval observations, it seems to be very unlikely that a lumbar artificial disc is loaded with a linear wear path.Testing according to ASTM F2423-05 with pure unidirectional motion does not reflect the kinematics of TDA patients‘ daily activities. Based on our findings it seems to be more reliable to predict the clinical wear behavior of an artificial disc replacement using the ISO/FDIS 18192-1 method. PMID:19050942