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Sample records for preconditioning improves maximal

  1. Ischemic preconditioning improves mitochondrial tolerance to experimental calcium overload.

    Science.gov (United States)

    Crestanello, Juan A; Doliba, Nicolai M; Babsky, Andriy M; Doliba, Natalia M; Niibori, Koki; Whitman, Glenn J R; Osbakken, Mary D

    2002-04-01

    Ca(2+) overload leads to mitochondrial uncoupling, decreased ATP synthesis, and myocardial dysfunction. Pharmacologically opening of mitochondrial K(ATP) channels decreases mitochondrial Ca(2+) uptake, improving mitochondrial function during Ca(2+) overload. Ischemic preconditioning (IPC), by activating mitochondrial K(ATP) channels, may attenuate mitochondrial Ca(2+) overload and improve mitochondrial function during reperfusion. The purpose of these experiments was to study the effect of IPC (1) on mitochondrial function and (2) on mitochondrial tolerance to experimental Ca(2+) overload. Rat hearts (n = 6/group) were subjected to (a) 30 min of equilibration, 25 min of ischemia, and 30 min of reperfusion (Control) or (b) two 5-min episodes of ischemic preconditioning, 25 min of ischemia, and 30 min of reperfusion (IPC). Developed pressure (DP) was measured. Heart mitochondria were isolated at end-Equilibration (end-EQ) and at end-Reperfusion (end-RP). Mitochondrial respiratory function (state 2, oxygen consumption with substrate only; state 3, oxygen consumption stimulated by ADP; state 4, oxygen consumption after cessation of ADP phosphorylation; respiratory control index (RCI, state 3/state 4); rate of oxidative phosphorylation (ADP/Deltat), and ADP:O ratio) was measured with polarography using alpha-ketoglutarate as a substrate in the presence of different Ca(2+) concentrations (0 to 5 x 10(-7) M) to simulate Ca(2+) overload. IPC improved DP at end-RP. IPC did not improve preischemic mitochondrial respiratory function or preischemic mitochondrial response to Ca(2+) loading. IPC improved state 3, ADP/Deltat, and RCI during RP. Low Ca(2+) levels (0.5 and 1 x 10(-7) M) stimulated mitochondrial function in both groups predominantly in IPC. The Control group showed evidence of mitochondrial uncoupling at lower Ca(2+) concentrations (1 x 10(-7) M). IPC preserved state 3 at high Ca(2+) concentrations. The cardioprotective effect of IPC results, in part, from

  2. Combinatorial therapy of exercise-preconditioning and nanocurcumin formulation supplementation improves cardiac adaptation under hypobaric hypoxia.

    Science.gov (United States)

    Nehra, Sarita; Bhardwaj, Varun; Bansal, Anju; Saraswat, Deepika

    2017-09-26

    Chronic hypobaric hypoxia (cHH) mediated cardiac insufficiencies are associated with pathological damage. Sustained redox stress and work load are major causative agents of cardiac insufficiencies under cHH. Despite the advancements made in pharmacological (anti-oxidants, vasodilators) and non-pharmacological therapeutics (acclimatization strategies and schedules), only partial success has been achieved in improving cardiac acclimatization to cHH. This necessitates the need for potent combinatorial therapies to improve cardiac acclimatization at high altitudes. We hypothesize that a combinatorial therapy comprising preconditioning to mild aerobic treadmill exercise and supplementation with nanocurcumin formulation (NCF) consisting of nanocurcumin (NC) and pyrroloquinoline quinone (PQQ) might improve cardiac adaptation at high altitudes. Adult Sprague-Dawley rats pre-conditioned to treadmill exercise and supplemented with NCF were exposed to cHH (7620 m altitude corresponding to pO2~8% at 28±2°C, relative humidity 55%±1%) for 3 weeks. The rat hearts were analyzed for changes in markers of oxidative stress (free radical leakage, lipid peroxidation, manganese-superoxide dismutase [MnSOD] activity), cardiac injury (circulating cardiac troponin I [TnI] and T [cTnT], myocardial creatine kinase [CK-MB]), metabolic damage (lactate dehydrogenase [LDH] and acetyl-coenzyme A levels, lactate and pyruvate levels) and bio-energetic insufficiency (ATP, p-AMPKα). Significant modulations (p≤0.05) in cardiac redox status, metabolic damage, cardiac injury and bio-energetics were observed in rats receiving both NCF supplementation and treadmill exercise-preconditioning compared with rats receiving only one of the treatments. The combinatorial therapeutic strategy showed a tremendous improvement in cardiac acclimatization to cHH compared to either exercise-preconditioning or NCF supplementation alone which was evident from the effective modulation in redox, metabolic, contractile

  3. Developing maximal neuromuscular power: part 2 - training considerations for improving maximal power production.

    Science.gov (United States)

    Cormie, Prue; McGuigan, Michael R; Newton, Robert U

    2011-02-01

    This series of reviews focuses on the most important neuromuscular function in many sport performances: the ability to generate maximal muscular power. Part 1, published in an earlier issue of Sports Medicine, focused on the factors that affect maximal power production while part 2 explores the practical application of these findings by reviewing the scientific literature relevant to the development of training programmes that most effectively enhance maximal power production. The ability to generate maximal power during complex motor skills is of paramount importance to successful athletic performance across many sports. A crucial issue faced by scientists and coaches is the development of effective and efficient training programmes that improve maximal power production in dynamic, multi-joint movements. Such training is referred to as 'power training' for the purposes of this review. Although further research is required in order to gain a deeper understanding of the optimal training techniques for maximizing power in complex, sports-specific movements and the precise mechanisms underlying adaptation, several key conclusions can be drawn from this review. First, a fundamental relationship exists between strength and power, which dictates that an individual cannot possess a high level of power without first being relatively strong. Thus, enhancing and maintaining maximal strength is essential when considering the long-term development of power. Second, consideration of movement pattern, load and velocity specificity is essential when designing power training programmes. Ballistic, plyometric and weightlifting exercises can be used effectively as primary exercises within a power training programme that enhances maximal power. The loads applied to these exercises will depend on the specific requirements of each particular sport and the type of movement being trained. The use of ballistic exercises with loads ranging from 0% to 50% of one-repetition maximum (1RM) and

  4. Organisational readiness: exploring the preconditions for success in organisation-wide patient safety improvement programmes.

    Science.gov (United States)

    Burnett, Susan; Benn, Jonathan; Pinto, Anna; Parand, Anam; Iskander, Sandra; Vincent, Charles

    2010-08-01

    Patient safety has been high on the agenda for more than a decade. Despite many national initiatives aimed at improving patient safety, the challenge remains to find coherent and sustainable organisation-wide safety-improvement programmes. In the UK, the Safer Patients' Initiative (SPI) was established to address this challenge. Important in the success of such an endeavour is understanding 'readiness' at the organisational level, identifying the preconditions for success in this type of programme. This article reports on a case study of the four NHS organisations participating in the first phase of SPI, examining the perceptions of organisational readiness and the relationship of these factors with impact by those actively involved in the initiative. A mixed-methods design was used, involving a survey and semistructured interviews with senior executive leads, the principal SPI programme coordinator and the four operational leads in each of the SPI clinical work areas in all four organisations taking part in the first phase of SPI. This preliminary work would suggest that prior to the start of organisation-wide quality- and safety-improvement programmes, organisations would benefit from an assessment of readiness with time spent in the preparation of the organisational infrastructure, processes and culture. Furthermore, a better understanding of the preconditions that mark an organisation as ready for improvement work would allow policymakers to set realistic expectations about the outcomes of safety campaigns.

  5. Stress preconditioning of rooster semen before cryopreservation improves fertility potential of thawed sperm.

    Science.gov (United States)

    Feyzi, S; Sharafi, M; Rahimi, S

    2018-03-22

    Avian semen cryopreservation is not as successful as that seen in mammals. This failure is mostly attributed to unique physiological characteristics of poultry semen that make it susceptible to cryo-damages. Utilization of sublethal oxidative stress for preconditioning of sperm, as an innovative approach, improves the cryo-survival of sperm in certain mammalian species. The purpose of this study was to investigate the effects of preconditioning of rooster semen with sublethal oxidative stress [very low concentrations of nitric oxide (NO)] before cryopreservation on the quality and fertility potential of thawed sperm. Semen samples were collected from 20 roosters, twice a wk, and different concentrations of NO [0 (NO-0), 0.01 (NO-0.01), 0.1 (NO-0.1), 1 (NO-1), 10 (NO-10), and 100 μM (NO-100)] were used to investigate the effects of controlled induction of sublethal stress before semen cryopreservation on the thawed sperm performance. A significantly higher (P 0.05) affected by different concentrations of NO. Sperm exposed to NO-1 produced the highest percentage of viable spermatozoa (Annexin-/PI-), which was significantly different from the other samples. Finally, rate of fertility after artificial insemination was significantly higher (P < 0.05) following treatment with NO-1 compared to NO-0 and NO-0.1. Application of 1 μM NO as a sublethal oxidative stress before cryopreservation of sperm efficiently increased numerous quality indices of thawed sperm as well as its fertility potential.

  6. Exercise preconditioning improves behavioral functions following transient cerebral ischemia induced by 4-vessel occlusion (4-VO) in rats.

    Science.gov (United States)

    Tahamtan, Mahshid; Allahtavakoli, Mohammad; Abbasnejad, Mehdi; Roohbakhsh, Ali; Taghipour, Zahra; Taghavi, Mohsen; Khodadadi, Hassan; Shamsizadeh, Ali

    2013-12-01

    There is evidence that exercise decreases ischemia/reperfusion injury in rats. Since behavioral deficits are the main outcome in patients after stroke, our study was designed to investigate whether exercise preconditioning improves the acute behavioral functions and also brain inflammatory injury following cerebral ischemia. Male rats weighing 250-300 g were randomly allocated into five experimental groups. Exercise was performed on a treadmill 30min/day for 3 weeks. Ischemia was induced by 4-vessel occlusion method. Recognition memory was assessed by novel object recognition task (NORT) and step-through passive avoidance task. Sensorimotor function and motor movements were evaluated by adhesive removal test and ledged beam-walking test, respectively. Brain inflammatory injury was evaluated by histological assessment. In NORT, the discrimination ratio was decreased after ischemia (P test, a significant reduction in response latency was observed in the ischemic group. Exercise preconditioning significantly decreased the response latency in the ischemic rats (P test, latency to touch and remove the sticky labels from forepaw was increased following induction of ischemia (all P beam-walking test, the slip ratio was increased following ischemia (P < 0.05).  In the ischemia group, marked neuronal injury in hippocampus was observed. These neuropathological changes were attenuated by exercise preconditioning (P < 0.001). Our results showed that exercise preconditioning improves behavioral functions and maintains more viable cells in the dorsal hippocampus of the ischemic brain.

  7. Improved Algorithms OF CELF and CELF++ for Influence Maximization

    Directory of Open Access Journals (Sweden)

    Jiaguo Lv

    2014-06-01

    Full Text Available Motivated by the wide application in some fields, such as viral marketing, sales promotion etc, influence maximization has been the most important and extensively studied problem in social network. However, the most classical KK-Greedy algorithm for influence maximization is inefficient. Two major sources of the algorithm’s inefficiency were analyzed in this paper. With the analysis of algorithms CELF and CELF++, all nodes in the influenced set of u would never bring any marginal gain when a new seed u was produced. Through this optimization strategy, a lot of redundant nodes will be removed from the candidate nodes. Basing on the strategy, two improved algorithms of Lv_CELF and Lv_CELF++ were proposed in this study. To evaluate the two algorithms, the two algorithms with their benchmark algorithms of CELF and CELF++ were conducted on some real world datasets. To estimate the algorithms, influence degree and running time were employed to measure the performance and efficiency respectively. Experimental results showed that, compared with benchmark algorithms of CELF and CELF++, matching effects and higher efficiency were achieved by the new algorithms Lv_CELF and Lv_CELF++. Solutions with the proposed optimization strategy can be useful for the decisionmaking problems under the scenarios related to the influence maximization problem.

  8. Long-term, regular remote ischemic preconditioning improves endothelial function in patients with coronary heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Y.; Li, Y.P.; He, F.; Liu, X.Q.; Zhang, J.Y. [Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou (China)

    2015-04-28

    Remote ischemic preconditioning (RIPre) can prevent myocardial injury. The purpose of this study was to assess the beneficial effects of long-term regular RIPre on human arteries. Forty patients scheduled for coronary artery bypass graft (CABG) surgery were assigned randomly to a RIPre group (n=20) or coronary heart disease (CHD) group (n=20). Twenty patients scheduled for mastectomy were enrolled as a control group. RIPre was achieved by occluding arterial blood flow 5 min with a mercury sphygmomanometer followed by a 5-min reperfusion period, and this was repeated 4 times. The RIPre procedure was repeated 3 times a day for 20 days. In all patients, arterial fragments discarded during surgery were collected to evaluate endothelial function by flow-mediated dilation (FMD), CD34{sup +} monocyte count, and endothelial nitric oxide synthase (eNOS expression). Phosphorylation levels of STAT-3 and Akt were also assayed to explore the underlying mechanisms. Compared with the CHD group, long-term regular RIPre significantly improved FMD after 20 days (8.5±2.4 vs 4.9±4.2%, P<0.05) and significantly reduced troponin after CABG surgery (0.72±0.31 and 1.64±0.19, P<0.05). RIPre activated STAT-3 and increased CD34{sup +} endothelial progenitor cell counts found in arteries. Long-term, regular RIPre improved endothelial function in patients with CHD, possibly due to STAT-3 activation, and this may have led to an increase in endothelial progenitor cells.

  9. Improving the making ready process - Exploring the preconditions to work tasks in construction

    DEFF Research Database (Denmark)

    Lindhard, Søren; Wandahl, Søren

    2012-01-01

    preconditions have been revealed. The seven first is basically corresponding to the ones presented by Koskela (1999), while the last two are new and extends the existing knowledge. The preconditions are as follows: 1) Construction design and management. 2) Components and materials are present. 3) Workers...... are present. 4) Equipment and machinery are present. 5) Sufficient space for conduction. 6) Previous activities must be completed. 7) Climate conditions must be in order. 8) Safe working conditions in relation to national “Health and Safety at Work Act ” have to be present, 9) Known working conditions. Often...... productivity....

  10. Improved NGL recovery designs maximize operating flexibility and product recoveries

    International Nuclear Information System (INIS)

    Wilkinson, J.D.; Hudson, H.M.

    1992-01-01

    This paper reports that the historically cyclical nature in the market for ethane and propane has demonstrated the need for flexible natural gas liquids (NGL) recovery plants. NEwly developed and patented processes are now available which can provide ultra-high recovery of ethane (95%+) when demand for ethane is high and provide essentially complete ethane rejection without the normally concomitant reduction in propane recovery. This provides plant operators the flexibility to respond more readily to NGL market conditions, thus maximizing plant operating profits. The new process designs provide this flexibility without increasing utility requirements. In fact, utility consumption is often lower when compared to conventional designs. This same process technology can also be easily retrofit into existing plants with relatively quick payout of the modifications from both recovery and efficiency improvements

  11. Establishing Maximal Medical Improvement After Arthroscopic Rotator Cuff Repair.

    Science.gov (United States)

    Zuke, William A; Leroux, Timothy S; Gregory, Bonnie P; Black, Austin; Forsythe, Brian; Romeo, Anthony A; Verma, Nikhil N

    2018-03-01

    As health care transitions from a pay-for-service to a pay-for-performance infrastructure, the value of orthopaedic care must be defined accurately. Significant efforts have been made in defining quality and cost in arthroplasty; however, there remains a lag in ambulatory orthopaedic care. Two-year follow-up has been a general requirement for reporting outcomes after rotator cuff repair. However, this time requirement has not been established scientifically and is of increasing importance in the era of value-based health care. Given that arthroscopic rotator cuff repair is a common ambulatory orthopaedic procedure, the purpose of this study was to establish a time frame for maximal medical improvement (the state when improvement has stabilized) after arthroscopic rotator cuff repair. Systematic review. A systematic review of the literature was conducted, identifying studies reporting sequential patient-reported outcomes up to a minimum of 2 years after arthroscopic rotator cuff repair. The primary clinical outcome was patient-reported outcomes at 3-month, 6-month, 1-year, and 2-year follow-up. Secondary clinical outcomes included range of motion, strength, retears, and complications. Clinically significant improvement was determined between various time intervals by use of the minimal clinically important difference. The review included 19 studies including 1370 patients who underwent rotator cuff repair. Clinically significant improvement in patient-reported outcomes was seen up to 1 year after rotator cuff repair, but no clinical significance was noted from 1 year to 2 years. The majority of improvement in strength and range of motion was seen up to 6 months, but no clinically meaningful improvement was seen thereafter. All reported complications and the majority of retears occurred within 6 months after rotator cuff repair. After rotator cuff repair, a clinically significant improvement in patient-reported outcomes, range of motion, and strength was seen up to 1

  12. Kettlebell swing training improves maximal and explosive strength.

    Science.gov (United States)

    Lake, Jason P; Lauder, Mike A

    2012-08-01

    The aim of this study was to establish the effect that kettlebell swing (KB) training had on measures of maximum (half squat-HS-1 repetition maximum [1RM]) and explosive (vertical jump height-VJH) strength. To put these effects into context, they were compared with the effects of jump squat power training (JS-known to improve 1RM and VJH). Twenty-one healthy men (age = 18-27 years, body mass = 72.58 ± 12.87 kg) who could perform a proficient HS were tested for their HS 1RM and VJH pre- and post-training. Subjects were randomly assigned to either a KB or JS training group after HS 1RM testing and trained twice a week. The KB group performed 12-minute bouts of KB exercise (12 rounds of 30-second exercise, 30-second rest with 12 kg if 70 kg). The JS group performed at least 4 sets of 3 JS with the load that maximized peak power-Training volume was altered to accommodate different training loads and ranged from 4 sets of 3 with the heaviest load (60% 1RM) to 8 sets of 6 with the lightest load (0% 1RM). Maximum strength improved by 9.8% (HS 1RM: 165-181% body mass, p < 0.001) after the training intervention, and post hoc analysis revealed that there was no significant difference between the effect of KB and JS training (p = 0.56). Explosive strength improved by 19.8% (VJH: 20.6-24.3 cm) after the training intervention, and post hoc analysis revealed that the type of training did not significantly affect this either (p = 0.38). The results of this study clearly demonstrate that 6 weeks of biweekly KB training provides a stimulus that is sufficient to increase both maximum and explosive strength offering a useful alternative to strength and conditioning professionals seeking variety for their athletes.

  13. Pinocembrin ex vivo preconditioning improves the therapeutic efficacy of endothelial progenitor cells in monocrotaline-induced pulmonary hypertension in rats.

    Science.gov (United States)

    Ahmed, Lamiaa A; Rizk, Sherine M; El-Maraghy, Shohda A

    2017-08-15

    Pulmonary hypertension is still not curable and the available current therapies can only alleviate symptoms without hindering the progression of disease. The present study was directed to investigate the possible modulatory effect of pinocembrin on endothelial progenitor cells transplanted in monocrotaline-induced pulmonary hypertension in rats. Pulmonary hypertension was induced by a single subcutaneous injection of monocrotaline (60mg/kg). Endothelial progenitor cells were in vitro preconditioned with pinocembrin (25mg/L) for 30min before being i.v. injected into rats 2weeks after monocrotaline administration. Four weeks after monocrotaline administration, blood pressure, electrocardiography and right ventricular systolic pressure were recorded. Rats were sacrificed and serum was separated for determination of endothelin-1 and asymmetric dimethylarginine levels. Right ventricles and lungs were isolated for estimation of tumor necrosis factor-alpha and transforming growth factor-beta contents as well as caspase-3 activity. Moreover, protein expression of matrix metalloproteinase-9 and endothelial nitric oxide synthase in addition to myocardial connexin-43 was assessed. Finally, histological analysis of pulmonary arteries, cardiomyocyte cross-sectional area and right ventricular hypertrophy was performed and cryosections were done for estimation of cell homing. Preconditioning with pinocembrin provided a significant improvement in endothelial progenitor cells' effect towards reducing monocrotaline-induced elevation of inflammatory, fibrogenic and apoptotic markers. Furthermore, preconditioned cells induced a significant amelioration of endothelial markers and cell homing and prevented monocrotaline-induced changes in right ventricular function and histological analysis compared with native cells alone. In conclusion, pinocembrin significantly improves the therapeutic efficacy of endothelial progenitor cells in monocrotaline-induced pulmonary hypertension in rats

  14. Preconditioning methods to improve SAGD performance in heavy oil and bitumen reservoirs with variable oil phase viscosity

    Energy Technology Data Exchange (ETDEWEB)

    Gates, I.D. [Gushor Inc., Calgary, AB (Canada)]|[Calgary Univ., AB (Canada). Dept. of Chemical and Petroleum Engineering; Larter, S.R.; Adams, J.J.; Snowdon, L.; Jiang, C. [Gushor Inc., Calgary, AB (Canada)]|[Calgary Univ., Calgary, AB (Canada). Dept. of Geoscience

    2008-10-15

    This study investigated preconditioning techniques for altering reservoir fluid properties prior to steam assisted gravity drainage (SAGD) recovery processes. Viscosity-reducing agents were distributed in mobile reservoir water. Simulations were conducted to demonstrate the method's ability to modify oil viscosity prior to steam injection. The study simulated the action of water soluble organic solvents that preferentially partitioned in the oil phase. The solvent was injected with water into the reservoir in a slow waterflood that did not displace oil from the near wellbore region. A reservoir simulation model was used to investigate the technique. Shu's correlation was used to establish a viscosity correlation for the bitumen and solvent mixtures. Solvent injection was modelled by converting the oil phase viscosity through time. Over the first 2 years, oil rates of the preconditioned case were double that of the non-preconditioned case study. However, after 11 years, the preconditioned case's rates declined below rates observed in the non-preconditioned case. The model demonstrated that oil viscosity distributions were significantly altered using the preconditioners. The majority of the most viscous oil surrounding the production well was significantly reduced. It was concluded that accelerated steam chamber growth provided faster access to lower viscosity materials at the top of the reservoir. 12 refs., 9 figs.

  15. Preconditioned iterations to calculate extreme eigenvalues

    Energy Technology Data Exchange (ETDEWEB)

    Brand, C.W.; Petrova, S. [Institut fuer Angewandte Mathematik, Leoben (Austria)

    1994-12-31

    Common iterative algorithms to calculate a few extreme eigenvalues of a large, sparse matrix are Lanczos methods or power iterations. They converge at a rate proportional to the separation of the extreme eigenvalues from the rest of the spectrum. Appropriate preconditioning improves the separation of the eigenvalues. Davidson`s method and its generalizations exploit this fact. The authors examine a preconditioned iteration that resembles a truncated version of Davidson`s method with a different preconditioning strategy.

  16. Improving matrix-vector product performance and multi-level preconditioning for the parallel PCG package

    Energy Technology Data Exchange (ETDEWEB)

    McLay, R.T.; Carey, G.F.

    1996-12-31

    In this study we consider parallel solution of sparse linear systems arising from discretized PDE`s. As part of our continuing work on our parallel PCG Solver package, we have made improvements in two areas. The first is improving the performance of the matrix-vector product. Here on regular finite-difference grids, we are able to use the cache memory more efficiently for smaller domains or where there are multiple degrees of freedom. The second problem of interest in the present work is the construction of preconditioners in the context of the parallel PCG solver we are developing. Here the problem is partitioned over a set of processors subdomains and the matrix-vector product for PCG is carried out in parallel for overlapping grid subblocks. For problems of scaled speedup, the actual rate of convergence of the unpreconditioned system deteriorates as the mesh is refined. Multigrid and subdomain strategies provide a logical approach to resolving the problem. We consider the parallel trade-offs between communication and computation and provide a complexity analysis of a representative algorithm. Some preliminary calculations using the parallel package and comparisons with other preconditioners are provided together with parallel performance results.

  17. Altered expression of mitochondrial electron transport chain proteins and improved myocardial energetic state during late ischemic preconditioning

    NARCIS (Netherlands)

    J.A. Cabrera (Jesús); E.A. Ziemba (Elizabeth); L.H. Colbert (Lisa); L.B. Anderson (Lorraine); W.J. Sluiter (Wim); D.J.G.M. Duncker (Dirk); T.A. Butterick (Tammy); J. Sikora (Joseph); H.B. Ward (Herbert B.); R.F. Kelly (Rosemary); E.O. McFalls (Edward)

    2012-01-01

    textabstractAltered expression of mitochondrial electron transport proteins has been shown in early preconditioned myocardial tissue. We wished to determine whether these alterations persist in the Second Window of Protection (SWOP) and if so, whether a favorable energetic state is facilitated

  18. Research on Adaptive Optics Image Restoration Algorithm by Improved Expectation Maximization Method

    OpenAIRE

    Zhang, Lijuan; Li, Dongming; Su, Wei; Yang, Jinhua; Jiang, Yutong

    2014-01-01

    To improve the effect of adaptive optics images’ restoration, we put forward a deconvolution algorithm improved by the EM algorithm which joints multiframe adaptive optics images based on expectation-maximization theory. Firstly, we need to make a mathematical model for the degenerate multiframe adaptive optics images. The function model is deduced for the points that spread with time based on phase error. The AO images are denoised using the image power spectral density and support constrain...

  19. Maximization Network Throughput Based on Improved Genetic Algorithm and Network Coding for Optical Multicast Networks

    Science.gov (United States)

    Wei, Chengying; Xiong, Cuilian; Liu, Huanlin

    2017-12-01

    Maximal multicast stream algorithm based on network coding (NC) can improve the network's throughput for wavelength-division multiplexing (WDM) networks, which however is far less than the network's maximal throughput in terms of theory. And the existing multicast stream algorithms do not give the information distribution pattern and routing in the meantime. In the paper, an improved genetic algorithm is brought forward to maximize the optical multicast throughput by NC and to determine the multicast stream distribution by hybrid chromosomes construction for multicast with single source and multiple destinations. The proposed hybrid chromosomes are constructed by the binary chromosomes and integer chromosomes, while the binary chromosomes represent optical multicast routing and the integer chromosomes indicate the multicast stream distribution. A fitness function is designed to guarantee that each destination can receive the maximum number of decoding multicast streams. The simulation results showed that the proposed method is far superior over the typical maximal multicast stream algorithms based on NC in terms of network throughput in WDM networks.

  20. Hypoxic preconditioning with cobalt of bone marrow mesenchymal stem cells improves cell migration and enhances therapy for treatment of ischemic acute kidney injury.

    Directory of Open Access Journals (Sweden)

    Xiaofang Yu

    Full Text Available Mesenchymal stem cell (MSC administration is known to enhance the recovery of the kidney following injury. Here we tested the potential of hypoxic-preconditioned-MSC transplantation to enhance the efficacy of cell therapy on acute kidney injury (AKI by improving MSC migration to the injured kidney. Cobalt was used as hypoxia mimetic preconditioning (HMP. MSC were subjected to HMP through 24 h culture in 200 µmol/L cobalt. Compared to normoxia cultured MSC (NP-MSC, HMP significantly increased the expression of HIF-1α and CXCR4 in MSC and enhanced the migration of MSC in vitro. This effect was lost when MSC were treated with siRNA targeting HIF-1α or CXCR4 antagonist. SPIO labeled MSC were administered to rats with I/R injury followed immediately by magnetic resonance imaging. Imaging clearly showed that HMP-MSC exhibited greater migration and a longer retention time in the ischemic kidney than NP-MSC. Histological evaluation showed more HMP-MSC in the glomerular capillaries of ischemic kidneys than in the kidneys receiving NP-MSC. Occasional tubules showed iron labeling in the HMP group, while no tubules had iron labeling in NP group, indicating the possibility of tubular transdifferentiation after HMP. These results were also confirmed by fluorescence microscopy study using CM-DiI labeling. The increased recruitment of HMP-MSC was associated with reduced kidney injury and enhanced functional recovery. This effect was also related to the increased paracrine action by HMP-MSC. Thus we suggest that by enhancing MSC migration and prolonging kidney retention, hypoxic preconditioning of MSC may be a useful approach for developing AKI cell therapy.

  1. Improving the Accuracy of Predicting Maximal Oxygen Consumption (VO2pk)

    Science.gov (United States)

    Downs, Meghan E.; Lee, Stuart M. C.; Ploutz-Snyder, Lori; Feiveson, Alan

    2016-01-01

    Maximal oxygen (VO2pk) is the maximum amount of oxygen that the body can use during intense exercise and is used for benchmarking endurance exercise capacity. The most accurate method to determineVO2pk requires continuous measurements of ventilation and gas exchange during an exercise test to maximal effort, which necessitates expensive equipment, a trained staff, and time to set-up the equipment. For astronauts, accurate VO2pk measures are important to assess mission critical task performance capabilities and to prescribe exercise intensities to optimize performance. Currently, astronauts perform submaximal exercise tests during flight to predict VO2pk; however, while submaximal VO2pk prediction equations provide reliable estimates of mean VO2pk for populations, they can be unacceptably inaccurate for a given individual. The error in current predictions and logistical limitations of measuring VO2pk, particularly during spaceflight, highlights the need for improved estimation methods.

  2. Caffeine, but not bicarbonate, improves 6 min maximal performance in elite rowers

    DEFF Research Database (Denmark)

    Christensen, Peter Møller; Petersen, Mads H; Friis, Signe N

    2014-01-01

    This study examined the ergogenic effects in a 6 min maximal performance test (PT) on 12 elite rowers: 6 open-weight (mean ± SD; 25 ± 1 years, and 92 ± 3 kg) and 6 light-weight (25 ± 3 years, and 73 ± 6 kg), following supplementation with caffeine (CAF), sodium bicarbonate (SB), and the combination.......05) than in open-weight rowers (0.3% ± 0.8%; P > 0.05). No difference between interventions was observed for readiness and stomach comfort before PT and perceived exertion during PT. This study demonstrates that caffeine ingestion does improve performance in elite rowing. In contrast sodium bicarbonate...

  3. Crossfit-based high-intensity power training improves maximal aerobic fitness and body composition.

    Science.gov (United States)

    Smith, Michael M; Sommer, Allan J; Starkoff, Brooke E; Devor, Steven T

    2013-11-01

    The purpose of this study was to examine the effects of a crossfit-based high-intensity power training (HIPT) program on aerobic fitness and body composition. Healthy subjects of both genders (23 men, 20 women) spanning all levels of aerobic fitness and body composition completed 10 weeks of HIPT consisting of lifts such as the squat, deadlift, clean, snatch, and overhead press performed as quickly as possible. Additionally, this crossfit-based HIPT program included skill work for the improvement of traditional Olympic lifts and selected gymnastic exercises. Body fat percentage was estimated using whole-body plethysmography, and maximal aerobic capacity (VO2max) was measured by analyzing expired gasses during a Bruce protocol maximal graded treadmill test. These variables were measured again after 10 weeks of training and compared for significant changes using a paired t-test. Results showed significant (p < 0.05) improvements of VO2max in men (43.10 ± 1.40 to 48.96 ± 1.42 ml · kg · min) and women (35.98 ± 1.60 to 40.22 ± 1.62 ml · kg · min) and decreased body fat percentage in men (22.2 ± 1.3 to 18.0 ± 1.3) and women (26.6 ± 2.0 to 23.2 ± 2.0). These improvements were significant across all levels of initial fitness. Significant correlations between absolute oxygen consumption and oxygen consumption relative to body weight was found in both men (r = 0.83, p < 0.001) and women (r = 0.94, p < 0.001), indicating that HIPT improved VO2max scaled to body weight independent of changes to body composition. Our data show that HIPT significantly improves VO2max and body composition in subjects of both genders across all levels of fitness.

  4. Improved Expectation Maximization Algorithm for Gaussian Mixed Model Using the Kernel Method

    Directory of Open Access Journals (Sweden)

    Mohd Izhan Mohd Yusoff

    2013-01-01

    Full Text Available Fraud activities have contributed to heavy losses suffered by telecommunication companies. In this paper, we attempt to use Gaussian mixed model, which is a probabilistic model normally used in speech recognition to identify fraud calls in the telecommunication industry. We look at several issues encountered when calculating the maximum likelihood estimates of the Gaussian mixed model using an Expectation Maximization algorithm. Firstly, we look at a mechanism for the determination of the initial number of Gaussian components and the choice of the initial values of the algorithm using the kernel method. We show via simulation that the technique improves the performance of the algorithm. Secondly, we developed a procedure for determining the order of the Gaussian mixed model using the log-likelihood function and the Akaike information criteria. Finally, for illustration, we apply the improved algorithm to real telecommunication data. The modified method will pave the way to introduce a comprehensive method for detecting fraud calls in future work.

  5. Kronecker Products on Preconditioning

    KAUST Repository

    Gao, Longfei

    2013-01-01

    techniques have become increasingly popular due to their great potential on large scale computation. In this work, we present preconditioning techniques for linear systems built with tensor product basis functions. Efficient algorithms are designed

  6. [The relationship between ischemic preconditioning-induced infarction size limitation and duration of test myocardial ischemia].

    Science.gov (United States)

    Blokhin, I O; Galagudza, M M; Vlasov, T D; Nifontov, E M; Petrishchev, N N

    2008-07-01

    Traditionally infarction size reduction by ischemic preconditioning is estimated in duration of test ischemia. This approach limits the understanding of real antiischemic efficacy of ischemic preconditioning. Present study was performed in the in vivo rat model of regional myocardial ischemia-reperfusion and showed that protective effect afforded by ischemic preconditioning progressively decreased with prolongation of test ischemia. There were no statistically significant differences in infarction size between control and preconditioned animals when the duration of test ischemia was increased up to 1 hour. Preconditioning ensured maximal infarction-limiting effect in duration of test ischemia varying from 20 to 40 minutes.

  7. Research on Adaptive Optics Image Restoration Algorithm by Improved Expectation Maximization Method

    Directory of Open Access Journals (Sweden)

    Lijuan Zhang

    2014-01-01

    Full Text Available To improve the effect of adaptive optics images’ restoration, we put forward a deconvolution algorithm improved by the EM algorithm which joints multiframe adaptive optics images based on expectation-maximization theory. Firstly, we need to make a mathematical model for the degenerate multiframe adaptive optics images. The function model is deduced for the points that spread with time based on phase error. The AO images are denoised using the image power spectral density and support constraint. Secondly, the EM algorithm is improved by combining the AO imaging system parameters and regularization technique. A cost function for the joint-deconvolution multiframe AO images is given, and the optimization model for their parameter estimations is built. Lastly, the image-restoration experiments on both analog images and the real AO are performed to verify the recovery effect of our algorithm. The experimental results show that comparing with the Wiener-IBD or RL-IBD algorithm, our iterations decrease 14.3% and well improve the estimation accuracy. The model distinguishes the PSF of the AO images and recovers the observed target images clearly.

  8. Improved lower extremity pedaling mechanics in individuals with stroke under maximal workloads.

    Science.gov (United States)

    Linder, Susan M; Rosenfeldt, Anson B; Bazyk, Andrew S; Koop, Mandy Miller; Ozinga, Sarah; Alberts, Jay L

    2018-05-01

    Background Individuals with stroke present with motor control deficits resulting in the abnormal activation and timing of agonist and antagonist muscles and inefficient movement patterns. The analysis of pedaling biomechanics provides a window into understanding motor control deficits, which vary as a function of workload. Understanding the relationship between workload and motor control is critical when considering exercise prescription during stroke rehabilitation. Objectives To characterize pedaling kinematics and motor control processes under conditions in which workload was systematically increased to an eventual patient-specific maximum. Methods A cohort study was conducted in which 18 individuals with chronic stroke underwent a maximal exertion cardiopulmonary exercise test on a stationary cycle ergometer, during which pedaling torque was continuously recorded. Measures of force production, pedaling symmetry, and pedaling smoothness were obtained. Results Mean Torque increased significantly (p pedaling action, improved from 0.37(0.29) to 0.29(0.35) during downstroke (p = 0.007), and worsened during the upstroke: -0.37(0.38) to -0.62(0.46) (p pedaling improved significantly from initial to terminal workloads (p pedaling kinematics at terminal workloads indicate that individuals with stroke demonstrate improved motor control with respect to the timing, sequencing, and activation of hemiparetic lower extremity musculature compared to lower workloads. Therapeutic prescription involving higher resistance may be necessary to sufficiently engage and activate the paretic lower extremity.

  9. Matrix preconditioning: a robust operation for optical linear algebra processors.

    Science.gov (United States)

    Ghosh, A; Paparao, P

    1987-07-15

    Analog electrooptical processors are best suited for applications demanding high computational throughput with tolerance for inaccuracies. Matrix preconditioning is one such application. Matrix preconditioning is a preprocessing step for reducing the condition number of a matrix and is used extensively with gradient algorithms for increasing the rate of convergence and improving the accuracy of the solution. In this paper, we describe a simple parallel algorithm for matrix preconditioning, which can be implemented efficiently on a pipelined optical linear algebra processor. From the results of our numerical experiments we show that the efficacy of the preconditioning algorithm is affected very little by the errors of the optical system.

  10. Maximizing flexibility and learning; using learning technology to improve course programs in higher education

    OpenAIRE

    Aasbrenn, Martin; Bingen, Hanne Maria

    2009-01-01

    ICDE 23rd World Conference. Including EADTU Annual Conference 7-10 June, 2009 The Netherlands, Maastricht MECC We propose a framework for development of course programs in higher education : Our vision is that all teaching in higher education should aim for maximal learning with maximal flexibility. Learning technology could be used to optimize this, implemented through continuous feedback from the students.

  11. Increasing Winter Maximal Metabolic Rate Improves Intrawinter Survival in Small Birds.

    Science.gov (United States)

    Petit, Magali; Clavijo-Baquet, Sabrina; Vézina, François

    Small resident bird species living at northern latitudes increase their metabolism in winter, and this is widely assumed to improve their chances of survival. However, the relationship between winter metabolic performance and survival has yet to be demonstrated. Using capture-mark-recapture, we followed a population of free-living black-capped chickadees (Poecile atricapillus) over 3 yr and evaluated their survival probability within and among winters. We also measured the size-independent body mass (M s ), hematocrit (Hct), basal metabolic rate (BMR), and maximal thermogenic capacity (Msum) and investigated how these parameters influenced survival within and among winters. Results showed that survival probability was high and constant both within (0.92) and among (0.96) winters. They also showed that while M s , Hct, and BMR had no significant influence, survival was positively related to Msum-following a sigmoid relationship-within but not among winter. Birds expressing an Msum below 1.26 W (i.e., similar to summer levels) had a winter. Our data therefore suggest that black-capped chickadees that are either too slow or unable to adjust their phenotype from summer to winter have little chances of survival and thus that seasonal upregulation of metabolic performance is highly beneficial. This study is the first to document in an avian system the relationship between thermogenic capacity and winter survival, a proxy of fitness.

  12. Caffeine, but not bicarbonate, improves 6 min maximal performance in elite rowers.

    Science.gov (United States)

    Christensen, Peter M; Petersen, Mads H; Friis, Signe N; Bangsbo, Jens

    2014-09-01

    This study examined the ergogenic effects in a 6 min maximal performance test (PT) on 12 elite rowers: 6 open-weight (mean ± SD; 25 ± 1 years, and 92 ± 3 kg) and 6 light-weight (25 ± 3 years, and 73 ± 6 kg), following supplementation with caffeine (CAF), sodium bicarbonate (SB), and the combination of both, in a double-blind randomized placebo (PLA) controlled design. PT was executed on 4 occasions, on separate days within a week, and in a non-fasted state, with standardized training being performed the day before PT. Protocols were as follows: (i) CAF, 3 mg/kg, 45 min prior to PT + calcium as SB-PLA; (ii) SB, 0.3 g/kg, 75 min prior to PT + dextrose as CAF-PLA; (iii) CAF + SB; and (iv) PLA; CAF-PLA + SB-PLA. The total distance in the CAF (1878 ± 97 m) and CAF + SB (1877 ± 97 m) was longer than in the PLA (1865 ± 104 m; P 0.05). No difference between interventions was observed for readiness and stomach comfort before PT and perceived exertion during PT. This study demonstrates that caffeine ingestion does improve performance in elite rowing. In contrast sodium bicarbonate does not appear to be ergogenic, but it does not abolish the ergogenic effect of caffeine.

  13. An Improved Optimization Function for Maximizing User Comfort with Minimum Energy Consumption in Smart Homes

    Directory of Open Access Journals (Sweden)

    Israr Ullah

    2017-11-01

    Full Text Available In the smart home environment, efficient energy management is a challenging task. Solutions are needed to achieve a high occupant comfort level with minimum energy consumption. User comfort is measured in terms of three fundamental parameters: (a thermal comfort, (b visual comfort and (c air quality. Temperature, illumination and CO 2 sensors are used to collect indoor contextual information. In this paper, we have proposed an improved optimization function to achieve maximum user comfort in the building environment with minimum energy consumption. A comprehensive formulation is done for energy optimization with detailed analysis. The Kalman filter algorithm is used to remove noise in sensor readings by predicting actual parameter values. For optimization, we have used genetic algorithm (GA and particle swarm optimization (PSO algorithms and performed comparative analysis with a baseline scheme on real data collected for a one-month duration in our lab’s indoor environment. Experimental results show that the proposed optimization function has achieved a 27 . 32 % and a 31 . 42 % reduction in energy consumption with PSO and GA, respectively. The user comfort index was also improved by 10 % i.e., from 0 . 86 to 0 . 96 . GA-based optimization results were better than PSO, as it has achieved almost the same user comfort with 4 . 19 % reduced energy consumption. Results show that the proposed optimization function gives better results than the baseline scheme in terms of user comfort and the amount of consumed energy. The proposed system can help with collecting the data about user preferences and energy consumption for long-term analysis and better decision making in the future for efficient resource utilization and overall profit maximization.

  14. Does treadmill running performance, heart rate and breathing rate response during maximal graded exercise improve after volitional respiratory muscle training?

    Science.gov (United States)

    Radhakrishnan, K; Sharma, V K; Subramanian, S K

    2017-05-10

    Maximal physical exertion in sports usually causes fatigue in the exercising muscles, but not in the respiratory muscles due to triggering of the Respiratory muscle metabo-reflex, a sympathetic vasoconstrictor response leading to preferential increment in blood flow to respiratory muscles. 1 We planned to investigate whether a six week yogic pranayama based Volitional Respiratory Muscle Training (VRMT) can improve maximal Graded Exercise Treadmill Test (GXTT) performance in healthy adult recreational sportspersons. Consecutive, consenting healthy adult recreational sportspersons aged 20.56±2.49 years (n=30), volunteered to 'baseline recording' of resting heart rate (HR), blood pressure (BP), respiratory rate (RR), and Bruce ramp protocol maximal GXTT until volitional exhaustion providing total test time (TTT), derived VO2max, Metabolic Equivalent of Task (METs), HR and BP response during maximal GXTT and drop in recovery HR data. After six weeks of observation, they underwent 'pre-intervention recording' followed by supervised VRMT intervention for 6 weeks (30 minutes a day; 5 days a week) and then 'post-intervention recording'. Repeated measures ANOVA with pairwise t statistical comparison was used to analyse the data. After supervised VRMT, we observed significant decrease in their resting supine RR (prespiratory muscle aerobic capacity, attenuation of respiratory muscle metabo-reflex, increase in cardiac stroke volume and autonomic resetting towards parasympatho-dominance. Yogic Pranayama based VRMT can be used in sports conditioning programme of athletes to further improve their maximal exercise performance, and as part of rehabilitation training during return from injury.

  15. Power maximization of a point absorber wave energy converter using improved model predictive control

    Science.gov (United States)

    Milani, Farideh; Moghaddam, Reihaneh Kardehi

    2017-08-01

    This paper considers controlling and maximizing the absorbed power of wave energy converters for irregular waves. With respect to physical constraints of the system, a model predictive control is applied. Irregular waves' behavior is predicted by Kalman filter method. Owing to the great influence of controller parameters on the absorbed power, these parameters are optimized by imperialist competitive algorithm. The results illustrate the method's efficiency in maximizing the extracted power in the presence of unknown excitation force which should be predicted by Kalman filter.

  16. Kronecker Products on Preconditioning

    KAUST Repository

    Gao, Longfei

    2013-08-01

    Numerical techniques for linear systems arising from discretization of partial differential equations are nowadays essential for understanding the physical world. Among these techniques, iterative methods and the accompanying preconditioning techniques have become increasingly popular due to their great potential on large scale computation. In this work, we present preconditioning techniques for linear systems built with tensor product basis functions. Efficient algorithms are designed for various problems by exploiting the Kronecker product structure in the matrices, inherited from tensor product basis functions. Specifically, we design preconditioners for mass matrices to remove the complexity from the basis functions used in isogeometric analysis, obtaining numerical performance independent of mesh size, polynomial order and continuity order; we also present a compound iteration preconditioner for stiffness matrices in two dimensions, obtaining fast convergence speed; lastly, for the Helmholtz problem, we present a strategy to `hide\\' its indefiniteness from Krylov subspace methods by eliminating the part of initial error that corresponds to those negative generalized eigenvalues. For all three cases, the Kronecker product structure in the matrices is exploited to achieve high computational efficiency.

  17. 40 CFR 80.52 - Vehicle preconditioning.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Vehicle preconditioning. 80.52 Section...) REGULATION OF FUELS AND FUEL ADDITIVES Reformulated Gasoline § 80.52 Vehicle preconditioning. (a) Initial vehicle preconditioning and preconditioning between tests with different fuels shall be performed in...

  18. Protocol for maximizing energy savings and indoor environmental quality improvements when retrofitting apartments

    Energy Technology Data Exchange (ETDEWEB)

    Noris, Federico [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Delp, William W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Vermeer, Kimberly [Urban Habitat Initiatives Inc., Boston, MA (United States); Adamkiewicz, Gary [Harvard School of Public Health, Boston, MA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Fisk, William J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-06-01

    The current focus on building energy retrofit provides an opportunity to simultaneously improve indoor environmental quality (IEQ). Toward this end, we developed a protocol for selecting packages of retrofits that both save energy and improve IEQ in apartments. The protocol specifies the methodology for selecting retrofits from a candidate list while addressing expected energy savings, IEQ impacts, and costs in an integrated manner. Interviews, inspections and measurements are specified to collect the needed input information. The protocol was applied to 17 apartments in three buildings in two different climates within California. Diagnostic measurements and surveys conducted before and after retrofit implementation indicate enhanced apartment performance.

  19. Improved Screening Mammogram Workflow by Maximizing PACS Streamlining Capabilities in an Academic Breast Center.

    Science.gov (United States)

    Pham, Ramya; Forsberg, Daniel; Plecha, Donna

    2017-04-01

    The aim of this study was to perform an operational improvement project targeted at the breast imaging reading workflow of mammography examinations at an academic medical center with its associated breast centers and satellite sites. Through careful analysis of the current workflow, two major issues were identified: stockpiling of paperwork and multiple worklists. Both issues were considered to cause significant delays to the start of interpreting screening mammograms. Four workflow changes were suggested (scanning of paperwork, worklist consolidation, use of chat functionality, and tracking of case distribution among trainees) and implemented in July 2015. Timestamp data was collected 2 months before (May-Jun) and after (Aug-Sep) the implemented changes. Generalized linear models were used to analyze the data. The results showed significant improvements for the interpretation of screening mammograms. The average time elapsed for time to open a case reduced from 70 to 28 min (60 % decrease, p workflow for diagnostic mammograms at large unaltered even with increased volume of mammography examinations (31 % increase of 4344 examinations for May-Jun to 5678 examinations for Aug-Sep). In conclusion, targeted efforts to improve the breast imaging reading workflow for screening mammograms in a teaching environment provided significant performance improvements without affecting the workflow of diagnostic mammograms.

  20. A Novel Multilayer Correlation Maximization Model for Improving CCA-Based Frequency Recognition in SSVEP Brain-Computer Interface.

    Science.gov (United States)

    Jiao, Yong; Zhang, Yu; Wang, Yu; Wang, Bei; Jin, Jing; Wang, Xingyu

    2018-05-01

    Multiset canonical correlation analysis (MsetCCA) has been successfully applied to optimize the reference signals by extracting common features from multiple sets of electroencephalogram (EEG) for steady-state visual evoked potential (SSVEP) recognition in brain-computer interface application. To avoid extracting the possible noise components as common features, this study proposes a sophisticated extension of MsetCCA, called multilayer correlation maximization (MCM) model for further improving SSVEP recognition accuracy. MCM combines advantages of both CCA and MsetCCA by carrying out three layers of correlation maximization processes. The first layer is to extract the stimulus frequency-related information in using CCA between EEG samples and sine-cosine reference signals. The second layer is to learn reference signals by extracting the common features with MsetCCA. The third layer is to re-optimize the reference signals set in using CCA with sine-cosine reference signals again. Experimental study is implemented to validate effectiveness of the proposed MCM model in comparison with the standard CCA and MsetCCA algorithms. Superior performance of MCM demonstrates its promising potential for the development of an improved SSVEP-based brain-computer interface.

  1. Improving Simulated Annealing by Replacing Its Variables with Game-Theoretic Utility Maximizers

    Science.gov (United States)

    Wolpert, David H.; Bandari, Esfandiar; Tumer, Kagan

    2001-01-01

    The game-theory field of Collective INtelligence (COIN) concerns the design of computer-based players engaged in a non-cooperative game so that as those players pursue their self-interests, a pre-specified global goal for the collective computational system is achieved as a side-effect. Previous implementations of COIN algorithms have outperformed conventional techniques by up to several orders of magnitude, on domains ranging from telecommunications control to optimization in congestion problems. Recent mathematical developments have revealed that these previously developed algorithms were based on only two of the three factors determining performance. Consideration of only the third factor would instead lead to conventional optimization techniques like simulated annealing that have little to do with non-cooperative games. In this paper we present an algorithm based on all three terms at once. This algorithm can be viewed as a way to modify simulated annealing by recasting it as a non-cooperative game, with each variable replaced by a player. This recasting allows us to leverage the intelligent behavior of the individual players to substantially improve the exploration step of the simulated annealing. Experiments are presented demonstrating that this recasting significantly improves simulated annealing for a model of an economic process run over an underlying small-worlds topology. Furthermore, these experiments reveal novel small-worlds phenomena, and highlight the shortcomings of conventional mechanism design in bounded rationality domains.

  2. Continuous quality improvement: a shared governance model that maximizes agent-specific knowledge.

    Science.gov (United States)

    Burkoski, Vanessa; Yoon, Jennifer

    2013-01-01

    Motivate, Innovate, Celebrate: an innovative shared governance model through the establishment of continuous quality improvement (CQI) councils was implemented across the London Health Sciences Centre (LHSC). The model leverages agent-specific knowledge at the point of care and provides a structure aimed at building human resources capacity and sustaining enhancements to quality and safe care delivery. Interprofessional and cross-functional teams work through the CQI councils to identify, formulate, execute and evaluate CQI initiatives. In addition to a structure that facilitates collaboration, accountability and ownership, a corporate CQI Steering Committee provides the forum for scaling up and spreading this model. Point-of-care staff, clinical management and educators were trained in LEAN methodology and patient experience-based design to ensure sufficient knowledge and resources to support the implementation.

  3. Entropy maximization

    Indian Academy of Sciences (India)

    Abstract. It is shown that (i) every probability density is the unique maximizer of relative entropy in an appropriate class and (ii) in the class of all pdf f that satisfy. ∫ fhi dμ = λi for i = 1, 2,...,...k the maximizer of entropy is an f0 that is pro- portional to exp(. ∑ ci hi ) for some choice of ci . An extension of this to a continuum of.

  4. Entropy Maximization

    Indian Academy of Sciences (India)

    It is shown that (i) every probability density is the unique maximizer of relative entropy in an appropriate class and (ii) in the class of all pdf that satisfy ∫ f h i d = i for i = 1 , 2 , … , … k the maximizer of entropy is an f 0 that is proportional to exp ⁡ ( ∑ c i h i ) for some choice of c i . An extension of this to a continuum of ...

  5. Orderings for conjugate gradient preconditionings

    Science.gov (United States)

    Ortega, James M.

    1991-01-01

    The effect of orderings on the rate of convergence of the conjugate gradient method with SSOR or incomplete Cholesky preconditioning is examined. Some results also are presented that help to explain why red/black ordering gives an inferior rate of convergence.

  6. Macro-elementwise preconditioning methods

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe

    2012-01-01

    Roč. 82, č. 10 (2012), s. 1952-1963 ISSN 0378-4754 Institutional research plan: CEZ:AV0Z30860518 Keywords : heterogeniety * elementwise preconditioning * block matrix partitioning * macro-elements Subject RIV: BA - General Mathematics Impact factor: 0.836, year: 2012 http://www.sciencedirect.com/science/journal/03784754

  7. EFFECT OF HEAT PRECONDITIONING BY MICROWAVE HYPERTHERMIA ON HUMAN SKELETAL MUSCLE AFTER ECCENTRIC EXERCISE

    Directory of Open Access Journals (Sweden)

    Norio Saga

    2008-03-01

    Full Text Available The purpose of this study was to clarify whether heat preconditioning results in less eccentric exercise-induced muscle damage and muscle soreness, and whether the repeated bout effect is enhanced by heat preconditioning prior to eccentric exercise. Nine untrained male volunteers aged 23 ± 3 years participated in this study. Heat preconditioning included treatment with a microwave hyperthermia unit (150 W, 20 min that was randomly applied to one of the subject's arms (MW; the other arm was used as a control (CON. One day after heat preconditioning, the subjects performed 24 maximal isokinetic eccentric contractions of the elbow flexors at 30°·s-1 (ECC1. One week after ECC1, the subjects repeated the procedure (ECC2. After each bout of exercise, maximal voluntary contraction (MVC, range of motion (ROM of the elbow joint, upper arm circumference, blood creatine kinase (CK activity and muscle soreness were measured. The subjects experienced both conditions at an interval of 3 weeks. MVC and ROM in the MW were significantly higher than those in the CON (p < 0.05 for ECC1; however, the heat preconditioning had no significant effect on upper arm circumference, blood CK activity, or muscle soreness following ECC1 and ECC2. Heat preconditioning may protect human skeletal muscle from eccentric exercise-induced muscle damage after a single bout of eccentric exercise but does not appear to promote the repeated bout effect after a second bout of eccentric exercise

  8. Utah ITS/CVO business plan : using technology to maximize highway safety and improve government and industry productivity

    Science.gov (United States)

    1997-12-31

    This plan was produced to maximize highway safety and increase government and industry productivity through the application of Intelligent Transportation System/Commercial Vehicle Operations (ITS/CVO) technologies to support regulatory and enforcemen...

  9. Is CP violation maximal

    International Nuclear Information System (INIS)

    Gronau, M.

    1984-01-01

    Two ambiguities are noted in the definition of the concept of maximal CP violation. The phase convention ambiguity is overcome by introducing a CP violating phase in the quark mixing matrix U which is invariant under rephasing transformations. The second ambiguity, related to the parametrization of U, is resolved by finding a single empirically viable definition of maximal CP violation when assuming that U does not single out one generation. Considerable improvement in the calculation of nonleptonic weak amplitudes is required to test the conjecture of maximal CP violation. 21 references

  10. Field-Split Preconditioned Inexact Newton Algorithms

    KAUST Repository

    Liu, Lulu

    2015-06-02

    The multiplicative Schwarz preconditioned inexact Newton (MSPIN) algorithm is presented as a complement to additive Schwarz preconditioned inexact Newton (ASPIN). At an algebraic level, ASPIN and MSPIN are variants of the same strategy to improve the convergence of systems with unbalanced nonlinearities; however, they have natural complementarity in practice. MSPIN is naturally based on partitioning of degrees of freedom in a nonlinear PDE system by field type rather than by subdomain, where a modest factor of concurrency can be sacrificed for physically motivated convergence robustness. ASPIN, originally introduced for decompositions into subdomains, is natural for high concurrency and reduction of global synchronization. We consider both types of inexact Newton algorithms in the field-split context, and we augment the classical convergence theory of ASPIN for the multiplicative case. Numerical experiments show that MSPIN can be significantly more robust than Newton methods based on global linearizations, and that MSPIN can be more robust than ASPIN and maintain fast convergence even for challenging problems, such as high Reynolds number Navier--Stokes equations.

  11. Field-Split Preconditioned Inexact Newton Algorithms

    KAUST Repository

    Liu, Lulu; Keyes, David E.

    2015-01-01

    The multiplicative Schwarz preconditioned inexact Newton (MSPIN) algorithm is presented as a complement to additive Schwarz preconditioned inexact Newton (ASPIN). At an algebraic level, ASPIN and MSPIN are variants of the same strategy to improve the convergence of systems with unbalanced nonlinearities; however, they have natural complementarity in practice. MSPIN is naturally based on partitioning of degrees of freedom in a nonlinear PDE system by field type rather than by subdomain, where a modest factor of concurrency can be sacrificed for physically motivated convergence robustness. ASPIN, originally introduced for decompositions into subdomains, is natural for high concurrency and reduction of global synchronization. We consider both types of inexact Newton algorithms in the field-split context, and we augment the classical convergence theory of ASPIN for the multiplicative case. Numerical experiments show that MSPIN can be significantly more robust than Newton methods based on global linearizations, and that MSPIN can be more robust than ASPIN and maintain fast convergence even for challenging problems, such as high Reynolds number Navier--Stokes equations.

  12. The multigrid preconditioned conjugate gradient method

    Science.gov (United States)

    Tatebe, Osamu

    1993-01-01

    A multigrid preconditioned conjugate gradient method (MGCG method), which uses the multigrid method as a preconditioner of the PCG method, is proposed. The multigrid method has inherent high parallelism and improves convergence of long wavelength components, which is important in iterative methods. By using this method as a preconditioner of the PCG method, an efficient method with high parallelism and fast convergence is obtained. First, it is considered a necessary condition of the multigrid preconditioner in order to satisfy requirements of a preconditioner of the PCG method. Next numerical experiments show a behavior of the MGCG method and that the MGCG method is superior to both the ICCG method and the multigrid method in point of fast convergence and high parallelism. This fast convergence is understood in terms of the eigenvalue analysis of the preconditioned matrix. From this observation of the multigrid preconditioner, it is realized that the MGCG method converges in very few iterations and the multigrid preconditioner is a desirable preconditioner of the conjugate gradient method.

  13. Innovations in Agriculture in Oregon: Farmers Irrigation District Improves Water Quality, Maximizes Water Conservation, and Generates Clean, Renewable Energy

    Science.gov (United States)

    The Hood River Farmers Irrigation District used $36.2 million in CWSRF loans for a multiple-year endeavor to convert the open canal system to a piped, pressurized irrigation system to maximize water conservation and restore reliable water delivery to crops

  14. Management of Preconditioned Calves and Impacts of Preconditioning.

    Science.gov (United States)

    Hilton, W Mark

    2015-07-01

    When studying the practice of preconditioning (PC) calves, many factors need to be examined to determine if cow-calf producers should make this investment. Factors such as average daily gain, feed efficiency, available labor, length of the PC period, genetics, and marketing options must be analyzed. The health sales price advantage is an additional benefit in producing and selling PC calves but not the sole determinant of PC's financially feasibility. Studies show that a substantial advantage of PC is the selling of additional pounds at a cost of gain well below the marginal return of producing those additional pounds. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Improving Large Cetacean Implantable Satellite Tag Designs to Maximize Tag Robustness and Minimize Health Effects to Individual Animals

    Science.gov (United States)

    2015-09-30

    to Maximize Tag Robustness and Minimize Health Effects to Individual Animals Alexandre N. Zerbini Cascadia Research Collective 218 ½ 4 th Ave W...penetrating devices (Moore et al. 2013) will be evaluated through experiments on cetacean carcasses . These experiments along with existing information on tag...Objective (1) during laboratory experiments and in cetacean carcasses ; 3) Examine structural tissue damage in the blubber, sub-dermal sheath and muscle

  16. Isoflurane preconditions myocardium against infarction via release of free radicals

    NARCIS (Netherlands)

    Müllenheim, Jost; Ebel, Dirk; Frässdorf, Jan; Preckel, Benedikt; Thämer, Volker; Schlack, Wolfgang

    2002-01-01

    BACKGROUND: Isoflurane exerts cardioprotective effects that mimic the ischemic preconditioning phenomenon. Generation of free radicals is implicated in ischemic preconditioning. The authors investigated whether isoflurane-induced preconditioning may involve release of free radicals. METHODS:

  17. A fast, preconditioned conjugate gradient Toeplitz solver

    Science.gov (United States)

    Pan, Victor; Schrieber, Robert

    1989-01-01

    A simple factorization is given of an arbitrary hermitian, positive definite matrix in which the factors are well-conditioned, hermitian, and positive definite. In fact, given knowledge of the extreme eigenvalues of the original matrix A, an optimal improvement can be achieved, making the condition numbers of each of the two factors equal to the square root of the condition number of A. This technique is to applied to the solution of hermitian, positive definite Toeplitz systems. Large linear systems with hermitian, positive definite Toeplitz matrices arise in some signal processing applications. A stable fast algorithm is given for solving these systems that is based on the preconditioned conjugate gradient method. The algorithm exploits Toeplitz structure to reduce the cost of an iteration to O(n log n) by applying the fast Fourier Transform to compute matrix-vector products. Matrix factorization is used as a preconditioner.

  18. Donor Preconditioning After the Onset of Brain Death With Dopamine Derivate n-Octanoyl Dopamine Improves Early Posttransplant Graft Function in the Rat.

    Science.gov (United States)

    Li, S; Korkmaz-Icöz, S; Radovits, T; Ruppert, M; Spindler, R; Loganathan, S; Hegedűs, P; Brlecic, P; Theisinger, B; Theisinger, S; Höger, S; Brune, M; Lasitschka, F; Karck, M; Yard, B; Szabó, G

    2017-07-01

    Heart transplantation is the therapy of choice for end-stage heart failure. However, hemodynamic instability, which has been demonstrated in brain-dead donors (BDD), could also affect the posttransplant graft function. We tested the hypothesis that treatment of the BDD with the dopamine derivate n-octanoyl-dopamine (NOD) improves donor cardiac and graft function after transplantation. Donor rats were given a continuous intravenous infusion of either NOD (0.882 mg/kg/h, BDD+NOD, n = 6) or a physiological saline vehicle (BDD, n = 9) for 5 h after the induction of brain death by inflation of a subdural balloon catheter. Controls were sham-operated (n = 9). In BDD, decreased left-ventricular contractility (ejection fraction; maximum rate of rise of left-ventricular pressure; preload recruitable stroke work), relaxation (maximum rate of fall of left-ventricular pressure; Tau), and increased end-diastolic stiffness were significantly improved after the NOD treatment. Following the transplantation, the NOD-treatment of BDD improved impaired systolic function and ventricular relaxation. Additionally, after transplantation increased interleukin-6, tumor necrosis factor TNF-α, NF-kappaB-p65, and nuclear factor (NF)-kappaB-p105 gene expression, and increased caspase-3, TNF-α and NF-kappaB protein expression could be significantly downregulated by the NOD treatment compared to BDD. BDD postconditioning with NOD through downregulation of the pro-apoptotic factor caspase-3, pro-inflammatory cytokines, and NF-kappaB may protect the heart against the myocardial injuries associated with brain death and ischemia/reperfusion. © 2017 The American Society of Transplantation and the American Society of Transplant Surgeons.

  19. Ischemic preconditioning protects against ischemic brain injury

    Directory of Open Access Journals (Sweden)

    Xiao-meng Ma

    2016-01-01

    Full Text Available In this study, we hypothesized that an increase in integrin αv ß 3 and its co-activator vascular endothelial growth factor play important neuroprotective roles in ischemic injury. We performed ischemic preconditioning with bilateral common carotid artery occlusion for 5 minutes in C57BL/6J mice. This was followed by ischemic injury with bilateral common carotid artery occlusion for 30 minutes. The time interval between ischemic preconditioning and lethal ischemia was 48 hours. Histopathological analysis showed that ischemic preconditioning substantially diminished damage to neurons in the hippocampus 7 days after ischemia. Evans Blue dye assay showed that ischemic preconditioning reduced damage to the blood-brain barrier 24 hours after ischemia. This demonstrates the neuroprotective effect of ischemic preconditioning. Western blot assay revealed a significant reduction in protein levels of integrin αv ß 3, vascular endothelial growth factor and its receptor in mice given ischemic preconditioning compared with mice not given ischemic preconditioning 24 hours after ischemia. These findings suggest that the neuroprotective effect of ischemic preconditioning is associated with lower integrin αv ß 3 and vascular endothelial growth factor levels in the brain following ischemia.

  20. Priming of the Cells: Hypoxic Preconditioning for Stem Cell Therapy.

    Science.gov (United States)

    Wei, Zheng Z; Zhu, Yan-Bing; Zhang, James Y; McCrary, Myles R; Wang, Song; Zhang, Yong-Bo; Yu, Shan-Ping; Wei, Ling

    2017-10-05

    Stem cell-based therapies are promising in regenerative medicine for protecting and repairing damaged brain tissues after injury or in the context of chronic diseases. Hypoxia can induce physiological and pathological responses. A hypoxic insult might act as a double-edged sword, it induces cell death and brain damage, but on the other hand, sublethal hypoxia can trigger an adaptation response called hypoxic preconditioning or hypoxic tolerance that is of immense importance for the survival of cells and tissues. This review was based on articles published in PubMed databases up to August 16, 2017, with the following keywords: "stem cells," "hypoxic preconditioning," "ischemic preconditioning," and "cell transplantation." Original articles and critical reviews on the topics were selected. Hypoxic preconditioning has been investigated as a primary endogenous protective mechanism and possible treatment against ischemic injuries. Many cellular and molecular mechanisms underlying the protective effects of hypoxic preconditioning have been identified. In cell transplantation therapy, hypoxic pretreatment of stem cells and neural progenitors markedly increases the survival and regenerative capabilities of these cells in the host environment, leading to enhanced therapeutic effects in various disease models. Regenerative treatments can mobilize endogenous stem cells for neurogenesis and angiogenesis in the adult brain. Furthermore, transplantation of stem cells/neural progenitors achieves therapeutic benefits via cell replacement and/or increased trophic support. Combinatorial approaches of cell-based therapy with additional strategies such as neuroprotective protocols, anti-inflammatory treatment, and rehabilitation therapy can significantly improve therapeutic benefits. In this review, we will discuss the recent progress regarding cell types and applications in regenerative medicine as well as future applications.

  1. Anesthetic Preconditioning as Endogenous Neuroprotection in Glaucoma

    Directory of Open Access Journals (Sweden)

    Tsung-Han Chou

    2018-01-01

    Full Text Available Blindness in glaucoma is the result of death of Retinal Ganglion Cells (RGCs and their axons. RGC death is generally preceded by a stage of reversible dysfunction and structural remodeling. Current treatments aimed at reducing intraocular pressure (IOP are ineffective or incompletely effective in management of the disease. IOP-independent neuroprotection or neuroprotection as adjuvant to IOP lowering in glaucoma remains a challenge as effective agents without side effects have not been identified yet. We show in DBA/2J mice with spontaneous IOP elevation and glaucoma that the lifespan of functional RGCs can be extended by preconditioning RGCs with retrobulbar lidocaine in one eye at four months of age that temporary blocks RGC axonal transport. The contralateral, PBS-injected eye served as control. Lidocaine-induced impairment of axonal transport to superior colliculi was assessed by intravitreal injection of cholera toxin B. Long-term (nine months effect of lidocaine were assessed on RGC electrical responsiveness (PERG, IOP, expression of relevant protein (BDNF, TrkB, PSD95, GFAP, Synaptophysin, and GAPDH and RGC density. While lidocaine treatment did not alter the age-related increase of IOP, TrkB expression was elevated, GFAP expression was decreased, RGC survival was improved by 35%, and PERG function was preserved. Results suggest that the lifespan of functional RGCs in mouse glaucoma can be extended by preconditioning RGCs in early stages of the disease using a minimally invasive treatment with retrobulbar lidocaine, a common ophthalmologic procedure. Lidocaine is inexpensive, safe and is approved by Food and Drug Administration (FDA to be administered intravenously.

  2. Efficacy of manual versus free-weight training to improve maximal strength and performance for microgravity conditions.

    Science.gov (United States)

    Behringer, Michael; Schüren, Thomas; McCourt, Molly; Mester, Joachim

    2016-01-01

    We tested a simple and compact device designed for manual resistance training in conditions of microgravity (Self-Powered Rope Trainer Duo (SPoRT Duo)) to increase muscle performance. Twenty-four participants (20.8 ± 2.1 years) were randomly assigned to a manual resistance group (n = 12) and a free-weight group (n = 12). Participants performed eight exercises (three sets; 8-12 efforts) either with free weights or the SPoRT Duo twice a week for 6 weeks. Maximal isometric force of trunk flexion, back extension and chest press increased (P at least 0.01, d at least 0.52) both in the manual resistance group (18.4% ± 15.0%; 32.7% ± 22.7%; 15.3% ± 9.7%) and free-weight group (18.0% ± 13.9%; 26.6% ± 28.9%; 13.3% ± 7.6%). The change in maximal isometric force of wide grip row in both groups (d at best 0.38) did not reach statistical significance (P at best 0.08). The squat one-repetition-maximum increased in the manual resistance group (29.8% ± 22.1%) and the free-weight group (32.4% ± 26.6%). Jump height, determined by a jump-and-reach test, increased in the free-weight group (9.8% ± 13.2%) but not in the manual resistance group (2.0% ± 8.5%). Manual resistance training was equally effective in increasing strength as traditional resistance training with free weights. This apparatus is a useful addition to current in-flight exercise systems.

  3. Remote Ischemic Preconditioning and Outcomes of Cardiac Surgery.

    OpenAIRE

    Hausenloy, DJ; Candilio, L; Evans, R; Ariti, C; Jenkins, DP; Kolvekar, S; Knight, R; Kunst, G; Laing, C; Nicholas, J; Pepper, J; Robertson, S; Xenou, M; Clayton, T; Yellon, DM

    2015-01-01

    : Whether remote ischemic preconditioning (transient ischemia and reperfusion of the arm) can improve clinical outcomes in patients undergoing coronary-artery bypass graft (CABG) surgery is not known. We investigated this question in a randomized trial. : We conducted a multicenter, sham-controlled trial involving adults at increased surgical risk who were undergoing on-pump CABG (with or without valve surgery) with blood cardioplegia. After anesthesia induction and before surgical incision, ...

  4. Convergence Analysis for the Multiplicative Schwarz Preconditioned Inexact Newton Algorithm

    KAUST Repository

    Liu, Lulu

    2016-10-26

    The multiplicative Schwarz preconditioned inexact Newton (MSPIN) algorithm, based on decomposition by field type rather than by subdomain, was recently introduced to improve the convergence of systems with unbalanced nonlinearities. This paper provides a convergence analysis of the MSPIN algorithm. Under reasonable assumptions, it is shown that MSPIN is locally convergent, and desired superlinear or even quadratic convergence can be obtained when the forcing terms are picked suitably.

  5. Convergence Analysis for the Multiplicative Schwarz Preconditioned Inexact Newton Algorithm

    KAUST Repository

    Liu, Lulu; Keyes, David E.

    2016-01-01

    The multiplicative Schwarz preconditioned inexact Newton (MSPIN) algorithm, based on decomposition by field type rather than by subdomain, was recently introduced to improve the convergence of systems with unbalanced nonlinearities. This paper provides a convergence analysis of the MSPIN algorithm. Under reasonable assumptions, it is shown that MSPIN is locally convergent, and desired superlinear or even quadratic convergence can be obtained when the forcing terms are picked suitably.

  6. Rapamycin preconditioning attenuates transient focal cerebral ischemia/reperfusion injury in mice.

    Science.gov (United States)

    Yin, Lele; Ye, Shasha; Chen, Zhen; Zeng, Yaoying

    2012-12-01

    Rapamycin, an mTOR inhibitor and immunosuppressive agent in clinic, has protective effects on traumatic brain injury and neurodegenerative diseases. But, its effects on transient focal ischemia/reperfusion disease are not very clear. In this study, we examined the effects of rapamycin preconditioning on mice treated with middle cerebral artery occlusion/reperfusion operation (MCAO/R). We found that the rapamycin preconditioning by intrahippocampal injection 20 hr before MCAO/R significantly improved the survival rate and longevity of mice. It also decreased the neurological deficit score, infracted areas and brain edema. In addition, rapamycin preconditioning decreased the production of NF-κB, TNF-α, and Bax, but not Bcl-2, an antiapoptotic protein in the ischemic area. From these results, we may conclude that rapamycin preconditioning attenuate transient focal cerebral ischemia/reperfusion injury and inhibits apoptosis induced by MCAO/R in mice.

  7. High-intensity interval training improves VO2peak, maximal lactate accumulation, time trial and competition performance in 9?11-year-old swimmers

    OpenAIRE

    Sperlich, Billy; Zinner, Christoph; Heilemann, Ilka; Kjendlie, Per-Ludvik; Holmberg, Hans-Christer; Mester, Joachim

    2010-01-01

    Training volume in swimming is usually very high when compared to the relatively short competition time. High-intensity interval training (HIIT) has been demonstrated to improve performance in a relatively short training period. The main purpose of the present study was to examine the effects of a 5-week HIIT versus high-volume training (HVT) in 9?11-year-old swimmers on competition performance, 100 and 2,000?m time (T 100?m and T 2,000?m), VO2peak and rate of maximal lactate accumulation (La...

  8. Combined incomplete LU and strongly implicit procedure preconditioning

    Energy Technology Data Exchange (ETDEWEB)

    Meese, E.A. [Univ. of Trondheim (Norway)

    1996-12-31

    For the solution of large sparse linear systems of equations, the Krylov-subspace methods have gained great merit. Their efficiency are, however, largely dependent upon preconditioning of the equation-system. A family of matrix factorisations often used for preconditioning, is obtained from a truncated Gaussian elimination, ILU(p). Less common, supposedly due to it`s restriction to certain sparsity patterns, is factorisations generated by the strongly implicit procedure (SIP). The ideas from ILU(p) and SIP are used in this paper to construct a generalized strongly implicit procedure, applicable to matrices with any sparsity pattern. The new algorithm has been run on some test equations, and efficiency improvements over ILU(p) was found.

  9. Multicomponent Exercise Improves Hemodynamic Parameters and Mobility, but Not Maximal Walking Speed, Transfer Capacity, and Executive Function of Older Type II Diabetic Patients

    Directory of Open Access Journals (Sweden)

    Hélio José Coelho Junior

    2018-01-01

    Full Text Available The present study aimed to investigate the effects of a 6-month multicomponent exercise program (MCEP on functional, cognitive, and hemodynamic parameters of older Type 2 diabetes mellitus (T2DM patients. Moreover, additional analyses were performed to evaluate if T2DM patients present impaired adaptability in response to physical exercise when compared to nondiabetic volunteers. A total of 72 T2DM patients and 72 age-matched healthy volunteers (CG were recruited and submitted to functional, cognitive, and hemodynamic evaluations before and after six months of a MCEP. The program of exercise was performed twice a week at moderate intensity. Results indicate T2DM and nondiabetic patients present an increase in mobility (i.e., usual walking speed after the MCEP. However, improvements in maximal walking speed, transfer capacity, and executive function were only observed in the CG. On the other hand, only T2DM group reveals a marked decline in blood pressure. In conclusion, data of the current study indicate that a 6-month MCEP improves mobility and reduce blood pressure in T2DM patients. However, maximal walking speed, transfer capacity, and executive function were only improved in CG, indicating that T2DM may present impaired adaptability in response to physical stimulus.

  10. Preconditioned Krylov subspace methods for eigenvalue problems

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Kesheng; Saad, Y.; Stathopoulos, A. [Univ. of Minnesota, Minneapolis, MN (United States)

    1996-12-31

    Lanczos algorithm is a commonly used method for finding a few extreme eigenvalues of symmetric matrices. It is effective if the wanted eigenvalues have large relative separations. If separations are small, several alternatives are often used, including the shift-invert Lanczos method, the preconditioned Lanczos method, and Davidson method. The shift-invert Lanczos method requires direct factorization of the matrix, which is often impractical if the matrix is large. In these cases preconditioned schemes are preferred. Many applications require solution of hundreds or thousands of eigenvalues of large sparse matrices, which pose serious challenges for both iterative eigenvalue solver and preconditioner. In this paper we will explore several preconditioned eigenvalue solvers and identify the ones suited for finding large number of eigenvalues. Methods discussed in this paper make up the core of a preconditioned eigenvalue toolkit under construction.

  11. Effects of Ischemic Preconditioning of Different Intraoperative Ischemic Times of Vascularized Bone Graft Rabbit Models

    Directory of Open Access Journals (Sweden)

    Ahmad Sukari Halim

    2013-11-01

    Full Text Available BackgroundIschemic preconditioning has been shown to improve the outcomes of hypoxic tolerance of the heart, brain, lung, liver, jejunum, skin, and muscle tissues. However, to date, no report of ischemic preconditioning on vascularized bone grafts has been published.MethodsSixteen rabbits were divided into four groups with ischemic times of 2, 6, 14, and 18 hours. Half of the rabbits in each group underwent ischemic preconditioning. The osteomyocutaneous flaps consisted of the tibia bone, from which the overlying muscle and skin were raised. The technique of ischemic preconditioning involved applying a vascular clamp to the pedicle for 3 cycles of 10 minutes each. The rabbits then underwent serial plain radiography and computed tomography imaging on the first, second, fourth, and sixth postoperative weeks. Following this, all of the rabbits were sacrificed and histological examinations were performed.ResultsThe results showed that for clinical analysis of the skin flaps and bone grafts, the preconditioned groups showed better survivability. In the plain radiographs, except for two non-preconditioned rabbits with intraoperative ischemic times of 6 hours, all began to show early callus formation at the fourth week. The computed tomography findings showed more callus formation in the preconditioned groups for all of the ischemic times except for the 18-hour group. The histological findings correlated with the radiological findings. There was no statistical significance in the difference between the two groups.ConclusionsIn conclusion, ischemic preconditioning improved the survivability of skin flaps and increased callus formation during the healing process of vascularized bone grafts.

  12. MO-G-17A-07: Improved Image Quality in Brain F-18 FDG PET Using Penalized-Likelihood Image Reconstruction Via a Generalized Preconditioned Alternating Projection Algorithm: The First Patient Results

    Energy Technology Data Exchange (ETDEWEB)

    Schmidtlein, CR; Beattie, B; Humm, J [Memorial Sloan Kettering Cancer Center, New York, NY (United States); Li, S; Wu, Z; Xu, Y [Sun Yat-sen University, Guangzhou, Guangdong (China); Zhang, J; Shen, L [Syracuse University, Syracuse, NY (United States); Vogelsang, L [VirtualScopics, Rochester, NY (United States); Feiglin, D; Krol, A [SUNY Upstate Medical University, Syracuse, NY (United States)

    2014-06-15

    Purpose: To investigate the performance of a new penalized-likelihood PET image reconstruction algorithm using the 1{sub 1}-norm total-variation (TV) sum of the 1st through 4th-order gradients as the penalty. Simulated and brain patient data sets were analyzed. Methods: This work represents an extension of the preconditioned alternating projection algorithm (PAPA) for emission-computed tomography. In this new generalized algorithm (GPAPA), the penalty term is expanded to allow multiple components, in this case the sum of the 1st to 4th order gradients, to reduce artificial piece-wise constant regions (“staircase” artifacts typical for TV) seen in PAPA images penalized with only the 1st order gradient. Simulated data were used to test for “staircase” artifacts and to optimize the penalty hyper-parameter in the root-mean-squared error (RMSE) sense. Patient FDG brain scans were acquired on a GE D690 PET/CT (370 MBq at 1-hour post-injection for 10 minutes) in time-of-flight mode and in all cases were reconstructed using resolution recovery projectors. GPAPA images were compared PAPA and RMSE-optimally filtered OSEM (fully converged) in simulations and to clinical OSEM reconstructions (3 iterations, 32 subsets) with 2.6 mm XYGaussian and standard 3-point axial smoothing post-filters. Results: The results from the simulated data show a significant reduction in the 'staircase' artifact for GPAPA compared to PAPA and lower RMSE (up to 35%) compared to optimally filtered OSEM. A simple power-law relationship between the RMSE-optimal hyper-parameters and the noise equivalent counts (NEC) per voxel is revealed. Qualitatively, the patient images appear much sharper and with less noise than standard clinical images. The convergence rate is similar to OSEM. Conclusions: GPAPA reconstructions using the 1{sub 1}-norm total-variation sum of the 1st through 4th-order gradients as the penalty show great promise for the improvement of image quality over that

  13. MO-G-17A-07: Improved Image Quality in Brain F-18 FDG PET Using Penalized-Likelihood Image Reconstruction Via a Generalized Preconditioned Alternating Projection Algorithm: The First Patient Results

    International Nuclear Information System (INIS)

    Schmidtlein, CR; Beattie, B; Humm, J; Li, S; Wu, Z; Xu, Y; Zhang, J; Shen, L; Vogelsang, L; Feiglin, D; Krol, A

    2014-01-01

    Purpose: To investigate the performance of a new penalized-likelihood PET image reconstruction algorithm using the 1 1 -norm total-variation (TV) sum of the 1st through 4th-order gradients as the penalty. Simulated and brain patient data sets were analyzed. Methods: This work represents an extension of the preconditioned alternating projection algorithm (PAPA) for emission-computed tomography. In this new generalized algorithm (GPAPA), the penalty term is expanded to allow multiple components, in this case the sum of the 1st to 4th order gradients, to reduce artificial piece-wise constant regions (“staircase” artifacts typical for TV) seen in PAPA images penalized with only the 1st order gradient. Simulated data were used to test for “staircase” artifacts and to optimize the penalty hyper-parameter in the root-mean-squared error (RMSE) sense. Patient FDG brain scans were acquired on a GE D690 PET/CT (370 MBq at 1-hour post-injection for 10 minutes) in time-of-flight mode and in all cases were reconstructed using resolution recovery projectors. GPAPA images were compared PAPA and RMSE-optimally filtered OSEM (fully converged) in simulations and to clinical OSEM reconstructions (3 iterations, 32 subsets) with 2.6 mm XYGaussian and standard 3-point axial smoothing post-filters. Results: The results from the simulated data show a significant reduction in the 'staircase' artifact for GPAPA compared to PAPA and lower RMSE (up to 35%) compared to optimally filtered OSEM. A simple power-law relationship between the RMSE-optimal hyper-parameters and the noise equivalent counts (NEC) per voxel is revealed. Qualitatively, the patient images appear much sharper and with less noise than standard clinical images. The convergence rate is similar to OSEM. Conclusions: GPAPA reconstructions using the 1 1 -norm total-variation sum of the 1st through 4th-order gradients as the penalty show great promise for the improvement of image quality over that currently

  14. Interventions to maximize facial cleanliness and achieve environmental improvement for trachoma elimination: A review of the grey literature.

    Directory of Open Access Journals (Sweden)

    Maryann G Delea

    2018-01-01

    Full Text Available Efforts are underway to scale-up the facial cleanliness and environmental improvement (F&E components of the World Health Organization's SAFE strategy for elimination of trachoma as a public health problem. Improving understanding of the F&E intervention landscape could inform advancements prior to scale-up, and lead to more effective and sustained behavior change.We systematically searched for relevant grey literature published from January 1965 through August 2016. Publications were eligible for review if they described interventions addressing F&E in the context of trachoma elimination programs. Subsequent to screening, we mapped attributes of F&E interventions. We then employed three behavior change frameworks to synthesize mapped data and identify potential intervention gaps. We identified 27 documents meeting inclusion criteria. With the exception of some recent programming, F&E interventions have largely focused on intermediate and distal antecedents of behavior change. Evidence from our analyses suggests many interventions are not designed to address documented determinants of improved F&E practices. No reviewed documents endorsed inclusion of intervention components related to behavioral maintenance or resilience-factors critical for sustaining improved behaviors.If left unaddressed, identified gaps in intervention content may continue to challenge uptake and sustainability of improved F&E behaviors. Stakeholders designing and implementing trachoma elimination programs should review their F&E intervention content and delivery approaches with an eye toward improvement, including better alignment with established behavior change theories and empirical evidence. Implementation should move beyond information dissemination, and appropriately employ a variety of behavior change techniques to address more proximal influencers of change.

  15. Interventions to maximize facial cleanliness and achieve environmental improvement for trachoma elimination: A review of the grey literature

    Science.gov (United States)

    Solomon, Hiwote; Solomon, Anthony W.; Freeman, Matthew C.

    2018-01-01

    Background Efforts are underway to scale-up the facial cleanliness and environmental improvement (F&E) components of the World Health Organization’s SAFE strategy for elimination of trachoma as a public health problem. Improving understanding of the F&E intervention landscape could inform advancements prior to scale-up, and lead to more effective and sustained behavior change. Methods/findings We systematically searched for relevant grey literature published from January 1965 through August 2016. Publications were eligible for review if they described interventions addressing F&E in the context of trachoma elimination programs. Subsequent to screening, we mapped attributes of F&E interventions. We then employed three behavior change frameworks to synthesize mapped data and identify potential intervention gaps. We identified 27 documents meeting inclusion criteria. With the exception of some recent programming, F&E interventions have largely focused on intermediate and distal antecedents of behavior change. Evidence from our analyses suggests many interventions are not designed to address documented determinants of improved F&E practices. No reviewed documents endorsed inclusion of intervention components related to behavioral maintenance or resilience–factors critical for sustaining improved behaviors. Conclusions If left unaddressed, identified gaps in intervention content may continue to challenge uptake and sustainability of improved F&E behaviors. Stakeholders designing and implementing trachoma elimination programs should review their F&E intervention content and delivery approaches with an eye toward improvement, including better alignment with established behavior change theories and empirical evidence. Implementation should move beyond information dissemination, and appropriately employ a variety of behavior change techniques to address more proximal influencers of change. PMID:29370169

  16. Interventions to maximize facial cleanliness and achieve environmental improvement for trachoma elimination: A review of the grey literature.

    Science.gov (United States)

    Delea, Maryann G; Solomon, Hiwote; Solomon, Anthony W; Freeman, Matthew C

    2018-01-01

    Efforts are underway to scale-up the facial cleanliness and environmental improvement (F&E) components of the World Health Organization's SAFE strategy for elimination of trachoma as a public health problem. Improving understanding of the F&E intervention landscape could inform advancements prior to scale-up, and lead to more effective and sustained behavior change. We systematically searched for relevant grey literature published from January 1965 through August 2016. Publications were eligible for review if they described interventions addressing F&E in the context of trachoma elimination programs. Subsequent to screening, we mapped attributes of F&E interventions. We then employed three behavior change frameworks to synthesize mapped data and identify potential intervention gaps. We identified 27 documents meeting inclusion criteria. With the exception of some recent programming, F&E interventions have largely focused on intermediate and distal antecedents of behavior change. Evidence from our analyses suggests many interventions are not designed to address documented determinants of improved F&E practices. No reviewed documents endorsed inclusion of intervention components related to behavioral maintenance or resilience-factors critical for sustaining improved behaviors. If left unaddressed, identified gaps in intervention content may continue to challenge uptake and sustainability of improved F&E behaviors. Stakeholders designing and implementing trachoma elimination programs should review their F&E intervention content and delivery approaches with an eye toward improvement, including better alignment with established behavior change theories and empirical evidence. Implementation should move beyond information dissemination, and appropriately employ a variety of behavior change techniques to address more proximal influencers of change.

  17. Low- and high-volume of intensive endurance training significantly improves maximal oxygen uptake after 10-weeks of training in healthy men.

    Directory of Open Access Journals (Sweden)

    Arnt Erik Tjønna

    Full Text Available Regular exercise training improves maximal oxygen uptake (VO2max, but the optimal intensity and volume necessary to obtain maximal benefit remains to be defined. A growing body of evidence suggests that exercise training with low-volume but high-intensity may be a time-efficient means to achieve health benefits. In the present study, we measured changes in VO2max and traditional cardiovascular risk factors after a 10 wk. training protocol that involved three weekly high-intensity interval sessions. One group followed a protocol which consisted of 4×4 min at 90% of maximal heart rate (HRmax interspersed with 3 min active recovery at 70% HRmax (4-AIT, the other group performed a single bout protocol that consisted of 1×4 min at 90% HRmax (1-AIT. Twenty-six inactive but otherwise healthy overweight men (BMI: 25-30, age: 35-45 y were randomized to either 1-AIT (n = 11 or 4-AIT (n = 13. After training, VO2max increased by 10% (∼5.0 mL⋅kg(-1⋅min(-1 and 13% (∼6.5 mL⋅kg(-1⋅min(-1 after 1-AIT and 4-AIT, respectively (group difference, p = 0.08. Oxygen cost during running at a sub-maximal workload was reduced by 14% and 13% after 1-AIT and 4-AIT, respectively. Systolic blood pressure decreased by 7.1 and 2.6 mmHg after 1-AIT and 4-AIT respectively, while diastolic pressure decreased by 7.7 and 6.1 mmHg (group difference, p = 0.84. Both groups had a similar ∼5% decrease in fasting glucose. Body fat, total cholesterol, LDL-cholesterol, and ox-LDL cholesterol only were significantly reduced after 4-AIT. Our data suggest that a single bout of AIT performed three times per week may be a time-efficient strategy to improve VO2max and reduce blood pressure and fasting glucose in previously inactive but otherwise healthy middle-aged individuals. The 1-AIT type of exercise training may be readily implemented as part of activities of daily living and could easily be translated into programs designed to improve public health

  18. Preconditioned alternating projection algorithms for maximum a posteriori ECT reconstruction

    International Nuclear Information System (INIS)

    Krol, Andrzej; Li, Si; Shen, Lixin; Xu, Yuesheng

    2012-01-01

    We propose a preconditioned alternating projection algorithm (PAPA) for solving the maximum a posteriori (MAP) emission computed tomography (ECT) reconstruction problem. Specifically, we formulate the reconstruction problem as a constrained convex optimization problem with the total variation (TV) regularization. We then characterize the solution of the constrained convex optimization problem and show that it satisfies a system of fixed-point equations defined in terms of two proximity operators raised from the convex functions that define the TV-norm and the constraint involved in the problem. The characterization (of the solution) via the proximity operators that define two projection operators naturally leads to an alternating projection algorithm for finding the solution. For efficient numerical computation, we introduce to the alternating projection algorithm a preconditioning matrix (the EM-preconditioner) for the dense system matrix involved in the optimization problem. We prove theoretically convergence of the PAPA. In numerical experiments, performance of our algorithms, with an appropriately selected preconditioning matrix, is compared with performance of the conventional MAP expectation-maximization (MAP-EM) algorithm with TV regularizer (EM-TV) and that of the recently developed nested EM-TV algorithm for ECT reconstruction. Based on the numerical experiments performed in this work, we observe that the alternating projection algorithm with the EM-preconditioner outperforms significantly the EM-TV in all aspects including the convergence speed, the noise in the reconstructed images and the image quality. It also outperforms the nested EM-TV in the convergence speed while providing comparable image quality. (paper)

  19. X Marks the Spot: Creating and Managing a Single Service Point to Improve Customer Service and Maximize Resources

    Science.gov (United States)

    Venner, Mary Ann; Keshmiripour, Seti

    2016-01-01

    This article will describe how merging service points in an academic library is an opportunity to improve customer service and utilize staffing resources more efficiently. Combining service points provides libraries with the ability to create a more positive library experience for patrons by minimizing the ping-pong effect for assistance. The…

  20. Brain Injury Lesion Imaging Using Preconditioned Quantitative Susceptibility Mapping without Skull Stripping.

    Science.gov (United States)

    Soman, S; Liu, Z; Kim, G; Nemec, U; Holdsworth, S J; Main, K; Lee, B; Kolakowsky-Hayner, S; Selim, M; Furst, A J; Massaband, P; Yesavage, J; Adamson, M M; Spincemallie, P; Moseley, M; Wang, Y

    2018-04-01

    Identifying cerebral microhemorrhage burden can aid in the diagnosis and management of traumatic brain injury, stroke, hypertension, and cerebral amyloid angiopathy. MR imaging susceptibility-based methods are more sensitive than CT for detecting cerebral microhemorrhage, but methods other than quantitative susceptibility mapping provide results that vary with field strength and TE, require additional phase maps to distinguish blood from calcification, and depict cerebral microhemorrhages as bloom artifacts. Quantitative susceptibility mapping provides universal quantification of tissue magnetic property without these constraints but traditionally requires a mask generated by skull-stripping, which can pose challenges at tissue interphases. We evaluated the preconditioned quantitative susceptibility mapping MR imaging method, which does not require skull-stripping, for improved depiction of brain parenchyma and pathology. Fifty-six subjects underwent brain MR imaging with a 3D multiecho gradient recalled echo acquisition. Mask-based quantitative susceptibility mapping images were created using a commonly used mask-based quantitative susceptibility mapping method, and preconditioned quantitative susceptibility images were made using precondition-based total field inversion. All images were reviewed by a neuroradiologist and a radiology resident. Ten subjects (18%), all with traumatic brain injury, demonstrated blood products on 3D gradient recalled echo imaging. All lesions were visible on preconditioned quantitative susceptibility mapping, while 6 were not visible on mask-based quantitative susceptibility mapping. Thirty-one subjects (55%) demonstrated brain parenchyma and/or lesions that were visible on preconditioned quantitative susceptibility mapping but not on mask-based quantitative susceptibility mapping. Six subjects (11%) demonstrated pons artifacts on preconditioned quantitative susceptibility mapping and mask-based quantitative susceptibility mapping

  1. DETERMINANTS OF MARKETING EFFICIENCY FOR PACKAGED WATER IN IMO STATE, NIGERIA: MAXIMIZING FIRMS ASSETS TO IMPROVE CONSUMER WELFARE

    Directory of Open Access Journals (Sweden)

    Ogbonnaya Ukeh OTEH

    2014-10-01

    Full Text Available Competition is necessary for enhanced customer welfare and efficiency. This study focused on marketing efficiency of packaged water in Imo state Nigeria. It specifically examined the socio-economic profile of the respondents; levels of marketing efficiency of packaged water and its determinants. The study employed purposive and multistage sampling technique in the selection of location and respondents respectively from whom information were elicited. Analytically, descriptive statistics, schematic diagram and OLS multiple regression models were used. Results showed that the respondents were predominantly married male adults, with average household size of 7 persons. They were fairly educated and experienced in the business. The study further revealed that age, education, household size and income were the major determinants of marketing efficiency of packaged water marketing in the area. The result also showed that net income, marketing cost, and marketing margin were higher in urban area, which implies that marketer in semi-urban areas were operating below optimum efficiency levels. This study therefore suggested the need to incorporate integrated logistics management and marketing strategies as a measure to reduce unnecessary marketing costs; capacity enhancement programmes for marketers and improvement in infrastructural development as a means of addressing marketing efficiency and customer welfare.

  2. A new dose of maximal-intensity interval training in hypoxia to improve body composition and hemoglobin and hematocrit levels: a pilot study.

    Science.gov (United States)

    Camacho-Cardenosa, Marta; Camacho-Cardenosa, Alba; Martínez Guardado, Ismael; Marcos-Serrano, Marta; Timon, Rafael; Olcina, Guillermo

    2017-01-01

    This pilot study had the aim to determine the effects of a new dose of maximal-intensity interval training in hypoxia in active adults. Twenty-four university student volunteers were randomly assigned to three groups: hypoxia group, normoxia group or control group. The eight training sessions consisted of 2 sets of 5 repeated sprints of 10 seconds with a recovery of 20 seconds between sprints and a recovery period of 10 minutes between sets. Body composition was measured following standard procedures. A blood sample was taken for an immediate hematocrit (HCT) and hemoglobin (Hb) concentration assessment. An all-out 3-ute test was performed to evaluate ventilation parameters and power. HCT and Hb were significantly higher for the hypoxia group in Post- and Det- (P=0.01; P=0.03). Fat mass percentage was significantly lower for the hypoxia group in both assessments (P=0.05; P=0.05). The hypoxia group underwent a significant increase in mean power after the recovery period. A new dose of 8 sessions of maximal-intensity interval training in hypoxia is enough to decrease the percentage of fat mass and to improve HCT and Hb parameters and mean muscle power in healthy and active adults.

  3. Weighted graph based ordering techniques for preconditioned conjugate gradient methods

    Science.gov (United States)

    Clift, Simon S.; Tang, Wei-Pai

    1994-01-01

    We describe the basis of a matrix ordering heuristic for improving the incomplete factorization used in preconditioned conjugate gradient techniques applied to anisotropic PDE's. Several new matrix ordering techniques, derived from well-known algorithms in combinatorial graph theory, which attempt to implement this heuristic, are described. These ordering techniques are tested against a number of matrices arising from linear anisotropic PDE's, and compared with other matrix ordering techniques. A variation of RCM is shown to generally improve the quality of incomplete factorization preconditioners.

  4. Ischemic Preconditioning of One Forearm Enhances Static and Dynamic Apnea

    DEFF Research Database (Denmark)

    Kjeld, Thomas; Rasmussen, Mads Reinholdt; Jattu, Timo

    2014-01-01

    INTRODUCTION: Ischemic preconditioning enhances ergometer cycling and swimming performance. We evaluated whether ischemic preconditioning of one forearm (four times for 5 min) also affects static breath hold and underwater swimming, whereas the effect of similar preconditioning on ergometer rowing...... preconditioning reduced the forearm oxygen saturation from 65% ± 7% to 19% ± 7% (mean ± SD; P right thigh.......05). CONCLUSIONS: We conclude that while the effect of ischemic preconditioning (of one forearm) on ergometer rowing was minimal, probably because of reduced muscle oxygenation during the warm-up, ischemic preconditioning does enhance both static and dynamic apnea, supporting that muscle ischemia is an important...

  5. Research on the Changes to the Lipid/Polymer Membrane Used in the Acidic Bitterness Sensor Caused by Preconditioning

    Directory of Open Access Journals (Sweden)

    Yuhei Harada

    2016-02-01

    Full Text Available A taste sensor that uses lipid/polymer membranes can evaluate aftertastes felt by humans using Change in membrane Potential caused by Adsorption (CPA measurements. The sensor membrane for evaluating bitterness, which is caused by acidic bitter substances such as iso-alpha acid contained in beer, needs an immersion process in monosodium glutamate (MSG solution, called “MSG preconditioning”. However, what happens to the lipid/polymer membrane during MSG preconditioning is not clear. Therefore, we carried out three experiments to investigate the changes in the lipid/polymer membrane caused by the MSG preconditioning, i.e., measurements of the taste sensor, measurements of the amount of the bitterness substance adsorbed onto the membrane and measurements of the contact angle of the membrane surface. The CPA values increased as the preconditioning process progressed, and became stable after 3 d of preconditioning. The response potentials to the reference solution showed the same tendency of the CPA value change during the preconditioning period. The contact angle of the lipid/polymer membrane surface decreased after 7 d of MSG preconditioning; in short, the surface of the lipid/polymer membrane became hydrophilic during MSG preconditioning. The amount of adsorbed iso-alpha acid was increased until 5 d preconditioning, and then it decreased. In this study, we revealed that the CPA values increased with the progress of MSG preconditioning in spite of the decrease of the amount of iso-alpha acid adsorbed onto the lipid/polymer membrane, and it was indicated that the CPA values increase because the sensor sensitivity was improved by the MSG preconditioning.

  6. Non-perturbative renormalization in coordinate space for N{sub f}=2 maximally twisted mass fermions with tree-level Symanzik improved gauge action

    Energy Technology Data Exchange (ETDEWEB)

    Cichy, Krzysztof [DESY, Zeuthen (Germany). NIC; Adam Mickiewicz Univ., Poznan (Poland). Faculty of Physics; Jansen, Karl [DESY, Zeuthen (Germany). NIC; Korcyl, Piotr [DESY, Zeuthen (Germany). NIC; Jagiellonian Univ., Krakow (Poland). M. Smoluchowski Inst. of Physics

    2012-07-15

    We present results of a lattice QCD application of a coordinate space renormalization scheme for the extraction of renormalization constants for flavour non-singlet bilinear quark operators. The method consists in the analysis of the small-distance behaviour of correlation functions in Euclidean space and has several theoretical and practical advantages, in particular: it is gauge invariant, easy to implement and has relatively low computational cost. The values of renormalization constants in the X-space scheme can be converted to the MS scheme via 4-loop continuum perturbative formulae. Our results for N{sub f}=2 maximally twisted mass fermions with tree-level Symanzik improved gauge action are compared to the ones from the RI-MOM scheme and show full agreement with this method. (orig.)

  7. Non-perturbative renormalization in coordinate space for Nf=2 maximally twisted mass fermions with tree-level Symanzik improved gauge action

    International Nuclear Information System (INIS)

    Cichy, Krzysztof; Adam Mickiewicz Univ., Poznan; Jansen, Karl; Korcyl, Piotr; Jagiellonian Univ., Krakow

    2012-07-01

    We present results of a lattice QCD application of a coordinate space renormalization scheme for the extraction of renormalization constants for flavour non-singlet bilinear quark operators. The method consists in the analysis of the small-distance behaviour of correlation functions in Euclidean space and has several theoretical and practical advantages, in particular: it is gauge invariant, easy to implement and has relatively low computational cost. The values of renormalization constants in the X-space scheme can be converted to the MS scheme via 4-loop continuum perturbative formulae. Our results for N f =2 maximally twisted mass fermions with tree-level Symanzik improved gauge action are compared to the ones from the RI-MOM scheme and show full agreement with this method. (orig.)

  8. Xenon preconditioning: molecular mechanisms and biological effects

    Directory of Open Access Journals (Sweden)

    Liu Wenwu

    2013-01-01

    Full Text Available Abstract Xenon is one of noble gases and has been recognized as an anesthetic for more than 50 years. Xenon possesses many of the characteristics of an ideal anesthetic, but it is not widely applied in clinical practice mainly because of its high cost. In recent years, numerous studies have demonstrated that xenon as an anesthetic can exert neuroprotective and cardioprotective effects in different models. Moreover, xenon has been applied in the preconditioning, and the neuroprotective and cardioprotective effects of xenon preconditioning have been investigated in a lot of studies in which some mechanisms related to these protections are proposed. In this review, we summarized these mechanisms and the biological effects of xenon preconditioning.

  9. Minimal residual method stronger than polynomial preconditioning

    Energy Technology Data Exchange (ETDEWEB)

    Faber, V.; Joubert, W.; Knill, E. [Los Alamos National Lab., NM (United States)] [and others

    1994-12-31

    Two popular methods for solving symmetric and nonsymmetric systems of equations are the minimal residual method, implemented by algorithms such as GMRES, and polynomial preconditioning methods. In this study results are given on the convergence rates of these methods for various classes of matrices. It is shown that for some matrices, such as normal matrices, the convergence rates for GMRES and for the optimal polynomial preconditioning are the same, and for other matrices such as the upper triangular Toeplitz matrices, it is at least assured that if one method converges then the other must converge. On the other hand, it is shown that matrices exist for which restarted GMRES always converges but any polynomial preconditioning of corresponding degree makes no progress toward the solution for some initial error. The implications of these results for these and other iterative methods are discussed.

  10. Projection preconditioning for Lanczos-type methods

    Energy Technology Data Exchange (ETDEWEB)

    Bielawski, S.S.; Mulyarchik, S.G.; Popov, A.V. [Belarusian State Univ., Minsk (Belarus)

    1996-12-31

    We show how auxiliary subspaces and related projectors may be used for preconditioning nonsymmetric system of linear equations. It is shown that preconditioned in such a way (or projected) system is better conditioned than original system (at least if the coefficient matrix of the system to be solved is symmetrizable). Two approaches for solving projected system are outlined. The first one implies straightforward computation of the projected matrix and consequent using some direct or iterative method. The second approach is the projection preconditioning of conjugate gradient-type solver. The latter approach is developed here in context with biconjugate gradient iteration and some related Lanczos-type algorithms. Some possible particular choices of auxiliary subspaces are discussed. It is shown that one of them is equivalent to using colorings. Some results of numerical experiments are reported.

  11. Dicranostiga leptopodu (Maxim.) Fedde extracts attenuated CCl4-induced acute liver damage in mice through increasing anti-oxidative enzyme activity to improve mitochondrial function.

    Science.gov (United States)

    Tang, Deping; Wang, Fang; Tang, Jinzhou; Mao, Aihong; Liao, Shiqi; Wang, Qin

    2017-01-01

    Dicranostiga Leptodu (Maxim.) fedde (DLF), a poppy plant, has been reported have many benefits and medicinal properties, including free radicals scavenging and detoxifying. However, the protective effect of DLF extracts against carbon tetrachloride (CCl 4 )-induced damage in mice liver has not been elucidated. Here, we demonstrated that DLF extracts attenuated CCl 4 -induced liver damage in mice through increasing anti-oxidative enzyme activity to improve mitochondrial function. In this study, the mice liver damage evoked by CCl 4 was marked by morphology changes, significant rise in lipid peroxidation, as well as alterations of mitochondrial respiratory function. Interestingly, pretreatment with DLF extracts attenuated CCl 4 -induced morphological damage and increasing of lipid peroxidation in mice liver. Additionally, DLF extracts improved mitochondrial function by preventing the disruption of respiratory chain and suppression of mitochondrial Na + K + -ATPase and Ca 2+ -ATPase activity. Furthermore, administration with DLF extracts elevated superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) levels and maintained the balance of redox status. This results showed that toxic protection effect of DLF extracts on mice liver is mediated by improving mitochondrial respiratory function and keeping the balance of redox status, which suggesting that DLF extracts could be used as potential toxic protection agent for the liver against hepatotoxic agent. Copyright © 2016. Published by Elsevier Masson SAS.

  12. Exogenous Gene Transmission of Isocitrate Dehydrogenase 2 Mimics Ischemic Preconditioning Protection.

    Science.gov (United States)

    Kolb, Alexander L; Corridon, Peter R; Zhang, Shijun; Xu, Weimin; Witzmann, Frank A; Collett, Jason A; Rhodes, George J; Winfree, Seth; Bready, Devin; Pfeffenberger, Zechariah J; Pomerantz, Jeremy M; Hato, Takashi; Nagami, Glenn T; Molitoris, Bruce A; Basile, David P; Atkinson, Simon J; Bacallao, Robert L

    2018-04-01

    Ischemic preconditioning confers organ-wide protection against subsequent ischemic stress. A substantial body of evidence underscores the importance of mitochondria adaptation as a critical component of cell protection from ischemia. To identify changes in mitochondria protein expression in response to ischemic preconditioning, we isolated mitochondria from ischemic preconditioned kidneys and sham-treated kidneys as a basis for comparison. The proteomic screen identified highly upregulated proteins, including NADP+-dependent isocitrate dehydrogenase 2 (IDH2), and we confirmed the ability of this protein to confer cellular protection from injury in murine S3 proximal tubule cells subjected to hypoxia. To further evaluate the role of IDH2 in cell protection, we performed detailed analysis of the effects of Idh2 gene delivery on kidney susceptibility to ischemia-reperfusion injury. Gene delivery of IDH2 before injury attenuated the injury-induced rise in serum creatinine ( P <0.05) observed in controls and increased the mitochondria membrane potential ( P <0.05), maximal respiratory capacity ( P <0.05), and intracellular ATP levels ( P <0.05) above those in controls. This communication shows that gene delivery of Idh2 can confer organ-wide protection against subsequent ischemia-reperfusion injury and mimics ischemic preconditioning. Copyright © 2018 by the American Society of Nephrology.

  13. Social group utility maximization

    CERN Document Server

    Gong, Xiaowen; Yang, Lei; Zhang, Junshan

    2014-01-01

    This SpringerBrief explains how to leverage mobile users' social relationships to improve the interactions of mobile devices in mobile networks. It develops a social group utility maximization (SGUM) framework that captures diverse social ties of mobile users and diverse physical coupling of mobile devices. Key topics include random access control, power control, spectrum access, and location privacy.This brief also investigates SGUM-based power control game and random access control game, for which it establishes the socially-aware Nash equilibrium (SNE). It then examines the critical SGUM-b

  14. Profit maximization mitigates competition

    DEFF Research Database (Denmark)

    Dierker, Egbert; Grodal, Birgit

    1996-01-01

    We consider oligopolistic markets in which the notion of shareholders' utility is well-defined and compare the Bertrand-Nash equilibria in case of utility maximization with those under the usual profit maximization hypothesis. Our main result states that profit maximization leads to less price...... competition than utility maximization. Since profit maximization tends to raise prices, it may be regarded as beneficial for the owners as a whole. Moreover, if profit maximization is a good proxy for utility maximization, then there is no need for a general equilibrium analysis that takes the distribution...... of profits among consumers fully into account and partial equilibrium analysis suffices...

  15. Preconditioning the modified conjugate gradient method ...

    African Journals Online (AJOL)

    In this paper, the convergence analysis of the conventional conjugate Gradient method was reviewed. And the convergence analysis of the modified conjugate Gradient method was analysed with our extension on preconditioning the algorithm. Convergence of the algorithm is a function of the condition number of M-1A.

  16. Equivalent operator preconditioning for elliptic problems

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe; Karátson, J.

    2009-01-01

    Roč. 50, č. 3 (2009), s. 297-380 ISSN 1017-1398 Institutional research plan: CEZ:AV0Z30860518 Keywords : Elliptic problem * Conjugate gradient method * preconditioning * equivalent operators * compact operators Subject RIV: BA - General Mathematics Impact factor: 0.716, year: 2009 http://en.scientificcommons.org/42514649

  17. Preconditioning of iterative methods - theory and applications

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe; Blaheta, Radim; Neytcheva, M.; Pultarová, I.

    2015-01-01

    Roč. 22, č. 6 (2015), s. 901-902 ISSN 1070-5325 Institutional support: RVO:68145535 Keywords : preconditioning * iterative methods * applications Subject RIV: BA - General Mathematics Impact factor: 1.431, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/nla.2016/epdf

  18. The structure of the polynomials in preconditioned BiCG algorithms and the switching direction of preconditioned systems

    OpenAIRE

    Itoh, Shoji; Sugihara, Masaaki

    2016-01-01

    We present a theorem that defines the direction of a preconditioned system for the bi-conjugate gradient (BiCG) method, and we extend it to preconditioned bi-Lanczos-type algorithms. We show that the direction of a preconditioned system is switched by construction and by the settings of the initial shadow residual vector. We analyze and compare the polynomial structures of four preconditioned BiCG algorithms.

  19. Improvement of Repeated-Sprint Ability and Horizontal-Jumping Performance in Elite Young Basketball Players With Low-Volume Repeated-Maximal-Power Training.

    Science.gov (United States)

    Gonzalo-Skok, Oliver; Tous-Fajardo, Julio; Arjol-Serrano, José Luis; Suarez-Arrones, Luis; Casajús, José Antonio; Mendez-Villanueva, Alberto

    2016-05-01

    To examine the effects of a low-volume repeated-power-ability (RPA) training program on repeated-sprint and change-of- direction (COD) ability and functional jumping performance. Twenty-two male elite young basketball players (age 16.2 ± 1.2 y, height 190.0 ± 10.0 cm, body mass 82.9 ± 10.1 kg) were randomly assigned either to an RPA-training group (n = 11) or a control group (n = 11). RPA training consisted of leg-press exercise, twice a week for 6 wk, of 1 or 2 blocks of 5 sets × 5 repetitions with 20 s of passive recovery between sets and 3 min between blocks with the load that maximized power output. Before and after training, performance was assessed by a repeated-sprint-ability (RSA) test, a repeated-COD-ability test, a hop for distance, and a drop jump followed by tests of a double unilateral hop with the right and left legs. Within-group and between-groups differences showed substantial improvements in slowest (RSAs) and mean time (RSAm) on RSA; best, slowest and mean time on repeated-COD ability; and unilateral right and left hop in the RPA group in comparison with control. While best time on RSA showed no improvement in any group, there was a large relationship (r = .68, 90% CI .43;.84) between the relative decrement in RSAm and RSAs, suggesting better sprint maintenance with RPA training. The relative improvements in best and mean repeated-COD ability were very largely correlated (r = .89, 90% CI .77;.94). Six weeks of lowvolume (4-14 min/wk) RPA training improved several physical-fitness tests in basketball players.

  20. Preconditioned characteristic boundary conditions based on artificial compressibility method for solution of incompressible flows

    Science.gov (United States)

    Hejranfar, Kazem; Parseh, Kaveh

    2017-09-01

    The preconditioned characteristic boundary conditions based on the artificial compressibility (AC) method are implemented at artificial boundaries for the solution of two- and three-dimensional incompressible viscous flows in the generalized curvilinear coordinates. The compatibility equations and the corresponding characteristic variables (or the Riemann invariants) are mathematically derived and then applied as suitable boundary conditions in a high-order accurate incompressible flow solver. The spatial discretization of the resulting system of equations is carried out by the fourth-order compact finite-difference (FD) scheme. In the preconditioning applied here, the value of AC parameter in the flow field and also at the far-field boundary is automatically calculated based on the local flow conditions to enhance the robustness and performance of the solution algorithm. The code is fully parallelized using the Concurrency Runtime standard and Parallel Patterns Library (PPL) and its performance on a multi-core CPU is analyzed. The incompressible viscous flows around a 2-D circular cylinder, a 2-D NACA0012 airfoil and also a 3-D wavy cylinder are simulated and the accuracy and performance of the preconditioned characteristic boundary conditions applied at the far-field boundaries are evaluated in comparison to the simplified boundary conditions and the non-preconditioned characteristic boundary conditions. It is indicated that the preconditioned characteristic boundary conditions considerably improve the convergence rate of the solution of incompressible flows compared to the other boundary conditions and the computational costs are significantly decreased.

  1. Maximally incompatible quantum observables

    Energy Technology Data Exchange (ETDEWEB)

    Heinosaari, Teiko, E-mail: teiko.heinosaari@utu.fi [Turku Centre for Quantum Physics, Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Schultz, Jussi, E-mail: jussi.schultz@gmail.com [Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Toigo, Alessandro, E-mail: alessandro.toigo@polimi.it [Dipartimento di Matematica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Milano, Via Celoria 16, I-20133 Milano (Italy); Ziman, Mario, E-mail: ziman@savba.sk [RCQI, Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 84511 Bratislava (Slovakia); Faculty of Informatics, Masaryk University, Botanická 68a, 60200 Brno (Czech Republic)

    2014-05-01

    The existence of maximally incompatible quantum observables in the sense of a minimal joint measurability region is investigated. Employing the universal quantum cloning device it is argued that only infinite dimensional quantum systems can accommodate maximal incompatibility. It is then shown that two of the most common pairs of complementary observables (position and momentum; number and phase) are maximally incompatible.

  2. Maximally incompatible quantum observables

    International Nuclear Information System (INIS)

    Heinosaari, Teiko; Schultz, Jussi; Toigo, Alessandro; Ziman, Mario

    2014-01-01

    The existence of maximally incompatible quantum observables in the sense of a minimal joint measurability region is investigated. Employing the universal quantum cloning device it is argued that only infinite dimensional quantum systems can accommodate maximal incompatibility. It is then shown that two of the most common pairs of complementary observables (position and momentum; number and phase) are maximally incompatible.

  3. Preconditioning mesenchymal stem cells with the mood stabilizers lithium and valproic acid enhances therapeutic efficacy in a mouse model of Huntington's disease.

    Science.gov (United States)

    Linares, Gabriel R; Chiu, Chi-Tso; Scheuing, Lisa; Leng, Yan; Liao, Hsiao-Mei; Maric, Dragan; Chuang, De-Maw

    2016-07-01

    Huntington's disease (HD) is a fatal neurodegenerative disorder caused by CAG repeat expansions in the huntingtin gene. Although, stem cell-based therapy has emerged as a potential treatment for neurodegenerative diseases, limitations remain, including optimizing delivery to the brain and donor cell loss after transplantation. One strategy to boost cell survival and efficacy is to precondition cells before transplantation. Because the neuroprotective actions of the mood stabilizers lithium and valproic acid (VPA) induce multiple pro-survival signaling pathways, we hypothesized that preconditioning bone marrow-derived mesenchymal stem cells (MSCs) with lithium and VPA prior to intranasal delivery to the brain would enhance their therapeutic efficacy, and thereby facilitate functional recovery in N171-82Q HD transgenic mice. MSCs were treated in the presence or absence of combined lithium and VPA, and were then delivered by brain-targeted single intranasal administration to eight-week old HD mice. Histological analysis confirmed the presence of MSCs in the brain. Open-field test revealed that ambulatory distance and mean velocity were significantly improved in HD mice that received preconditioned MSCs, compared to HD vehicle-control and HD mice transplanted with non-preconditioned MSCs. Greater benefits on motor function were observed in HD mice given preconditioned MSCs, while HD mice treated with non-preconditioned MSCs showed no functional benefits. Moreover, preconditioned MSCs reduced striatal neuronal loss and huntingtin aggregates in HD mice. Gene expression profiling of preconditioned MSCs revealed a robust increase in expression of genes involved in trophic effects, antioxidant, anti-apoptosis, cytokine/chemokine receptor, migration, mitochondrial energy metabolism, and stress response signaling pathways. Consistent with this finding, preconditioned MSCs demonstrated increased survival after transplantation into the brain compared to non-preconditioned cells

  4. Maximal power training induced different improvement in throwing velocity and muscle strength according to playing positions in elite male handball players.

    Science.gov (United States)

    Cherif, M; Chtourou, H; Souissi, N; Aouidet, A; Chamari, K

    2016-12-01

    This study was designed to assess the effect of strength and power training on throwing velocity and muscle strength in handball players according to their playing positions. Twenty-two male handball players were assigned to either an experimental group (n=11) or a control group (n=11) (age: 22.1 ± 3.0 years). They were asked to complete (i) the ball throwing velocity test and (ii) the one-repetition maximum (1-RM) tests for the half-back squat, the pull-over, the bench press, the developed neck, and the print exercises before and after 12 weeks of maximal power training. The training was designed to improve strength and power with an intensity of 85-95% of the 1RM. In addition to their usual routine handball training sessions, participants performed two sessions per week. During each session, they performed 3-5 sets of 3-8 repetitions with 3 min of rest in between. Then, they performed specific shots (i.e., 12 to 40). Ball-throwing velocity (p<0.001) was higher after the training period in rear line players (RL). The training programme resulted in an improvement of 1RM bench press (p<0.001), 1RM developed neck (p<0.001) and 1RM print (p<0.001) in both front line (FL) and RL. The control group showed a significant improvement only in ball-throwing velocity (p<0.01) and 1RM bench press (p<0.01) in RL. A significantly greater improvement was found in ball-throwing velocity (p<0.001), 1RM bench press (p<0.001), and 1RM half-back squat exercises in players of the central axis (CA) compared to the lateral axis (LA) (p<0.01). The power training programme induced significantly greater increases in ball-throwing velocity and muscle strength in FL than RL and in CA than LA axis players.

  5. Impact of ischemic preconditioning on functional sympatholysis during handgrip exercise in humans.

    NARCIS (Netherlands)

    Horiuchi, M.; Endo, J.; Thijssen, D.H.J.

    2015-01-01

    Repeated bouts of ischemia followed by reperfusion, known as ischemic preconditioning (IPC), is found to improve exercise performance. As redistribution of blood from the inactive areas to active skeletal muscles during exercise (i.e., functional sympatholysis) is important for exercise performance,

  6. A Hybrid Parallel Preconditioning Algorithm For CFD

    Science.gov (United States)

    Barth,Timothy J.; Tang, Wei-Pai; Kwak, Dochan (Technical Monitor)

    1995-01-01

    A new hybrid preconditioning algorithm will be presented which combines the favorable attributes of incomplete lower-upper (ILU) factorization with the favorable attributes of the approximate inverse method recently advocated by numerous researchers. The quality of the preconditioner is adjustable and can be increased at the cost of additional computation while at the same time the storage required is roughly constant and approximately equal to the storage required for the original matrix. In addition, the preconditioning algorithm suggests an efficient and natural parallel implementation with reduced communication. Sample calculations will be presented for the numerical solution of multi-dimensional advection-diffusion equations. The matrix solver has also been embedded into a Newton algorithm for solving the nonlinear Euler and Navier-Stokes equations governing compressible flow. The full paper will show numerous examples in CFD to demonstrate the efficiency and robustness of the method.

  7. Preconditions for Citizen Journalism: A Sociological Assessment

    OpenAIRE

    Hayley Watson

    2011-01-01

    The rise of the citizen journalist and increased attention to this phenomenon requires a sociological assessment that seeks to develop an understanding of how citizen journalism has emerged in contemporary society. This article makes a distinction between two different subcategories of citizen journalism, that is independent and dependent citizen journalism. The purpose of this article is to present four preconditions for citizen journalism to emerge in contemporary society: advanced technolo...

  8. Error Estimation in Preconditioned Conjugate Gradients

    Czech Academy of Sciences Publication Activity Database

    Strakoš, Zdeněk; Tichý, Petr

    2005-01-01

    Roč. 45, - (2005), s. 789-817 ISSN 0006-3835 R&D Projects: GA AV ČR 1ET400300415; GA AV ČR KJB1030306 Institutional research plan: CEZ:AV0Z10300504 Keywords : preconditioned conjugate gradient method * error bounds * stopping criteria * evaluation of convergence * numerical stability * finite precision arithmetic * rounding errors Subject RIV: BA - General Mathematics Impact factor: 0.509, year: 2005

  9. M-step preconditioned conjugate gradient methods

    Science.gov (United States)

    Adams, L.

    1983-01-01

    Preconditioned conjugate gradient methods for solving sparse symmetric and positive finite systems of linear equations are described. Necessary and sufficient conditions are given for when these preconditioners can be used and an analysis of their effectiveness is given. Efficient computer implementations of these methods are discussed and results on the CYBER 203 and the Finite Element Machine under construction at NASA Langley Research Center are included.

  10. Radiographers' preconditions for evidence-based radiography

    International Nuclear Information System (INIS)

    Ahonen, Sanna-Mari; Liikanen, Eeva

    2010-01-01

    Evidence-based practice (EBP) is essential in today's health care, but its establishment requires several preconditions from individuals and organizations (e.g. knowledge, understanding, attitudes, abilities, self-confidence, support, and resources). Previous studies suggest that radiographers do generate and use evidence in their work, but evidence-based radiography (EBR) is not yet used routinely as established practice, especially in terms of research utilization. This paper aims to describe radiographers' preconditions for EBR, and their participation in research activities. Main focus is on research utilization. Using an electronic questionnaire developed for this study, a survey was conducted: data collected from Finnish radiographers and radiotherapists (N = 438) were analysed both statistically and qualitatively. The final response rate was 39%. The results suggest radiographers' preconditions for EBR to consist of knowledge of research, significance of research activities, research-orientated way of working, and support. In addition, adequate resourcing is essential. Reading scientific journals, participation in research activities, a higher degree of education, and senior post seem to be significant promoters of EBR and research utilization. The results support the notion that EBR, and especially research utilization, are not yet well-established in Finland, and radiographers' viewpoints concerning the role and significance of research evidence and research activities still seem to vary.

  11. Moving force identification based on modified preconditioned conjugate gradient method

    Science.gov (United States)

    Chen, Zhen; Chan, Tommy H. T.; Nguyen, Andy

    2018-06-01

    This paper develops a modified preconditioned conjugate gradient (M-PCG) method for moving force identification (MFI) by improving the conjugate gradient (CG) and preconditioned conjugate gradient (PCG) methods with a modified Gram-Schmidt algorithm. The method aims to obtain more accurate and more efficient identification results from the responses of bridge deck caused by vehicles passing by, which are known to be sensitive to ill-posed problems that exist in the inverse problem. A simply supported beam model with biaxial time-varying forces is used to generate numerical simulations with various analysis scenarios to assess the effectiveness of the method. Evaluation results show that regularization matrix L and number of iterations j are very important influence factors to identification accuracy and noise immunity of M-PCG. Compared with the conventional counterpart SVD embedded in the time domain method (TDM) and the standard form of CG, the M-PCG with proper regularization matrix has many advantages such as better adaptability and more robust to ill-posed problems. More importantly, it is shown that the average optimal numbers of iterations of M-PCG can be reduced by more than 70% compared with PCG and this apparently makes M-PCG a preferred choice for field MFI applications.

  12. The effect of preconditioning cells under osmotic stress on high alcohol production

    Directory of Open Access Journals (Sweden)

    Logotetis Stilijanos

    2013-01-01

    Full Text Available This paper focuses on the research into the influence of salt on physiology of the yeast, Saccharomyces cerevisiae. Specifically, the work focused on how NaCl affected the growth, viability and fermentation performance of this yeast in laboratory-scale experiments. One of the main findings of the research presented involved the influ­ence of salt “preconditioning” of yeasts which represents a method of pre-culturing of cells in the presence of salt in an attempt to improve subsequent fermentation performance. Such an approach resulted in preconditioned yeasts having an improved capability to ferment high-sugar containing media (up to 60% w/v of glucose with increased cell viability and with increased levels of produced ethanol (higher than 20% in vol.. Salt-preconditioning was most likely influencing the stress-tolerance of yeasts by inducing the synthesis of key metabolites such as trehalose and glycerol which act to improve cells’ ability to withstand osmostress and ethanol toxicity. The industrial-scale trials using salt-preconditioned yeasts verified the benefit of the physiological engineering approach to practical fermentations. Overall, this research has demonstrated that a relatively simple method designed to adapt yeast cells physiologically - by salt-preconditioning - can have distinct advantages for al­cohol fermentation processes.

  13. Remote Ischaemic PrEconditioning of Human Myocardium (RIPE): study protocol for a double-blinded randomised controlled trial.

    Science.gov (United States)

    Deja, Marek A; Wiaderkiewicz, Ryszard; Czekaj, Piotr; Czech, Ewa; Malinowski, Marcin; Machej, Leszek; Węglarzy, Andrzej; Kowalówka, Adam; Piekarska, Magda; Szurlej, Bartosz; Latusek, Tomasz

    2018-01-01

    Remote preconditioning has been shown to be a potent protective phenomenon in many animals. Several studies aimed to demonstrate it was feasible in humans by trying to show its protective effect during cardiac surgery. Of these, some small studies and one larger trial were positive while two other bigger studies showed no effectiveness of remote preconditioning as assessed by levels of postoperatively released cardiac markers. Recently, two large clinical trials also failed to prove the benefit of remote preconditioning in cardiac surgery. No study showed that remote preconditioning actually increases resistance of human myocardium to standardised ischaemic and reperfusion stimulus in experimental settings. In animal studies, remote preconditioning was shown to improve mitochondrial function and structure, but such data on human myocardium are scarce. The aim of the study is to determine whether remote preconditioning protects human myocardium against ischaemia-reperfusion injury in both in vivo and in vitro conditions. The trial is designed as a single-centre, double-blinded, sham-controlled trial of 120 patients. We randomise (1:1) patients referred for coronary artery bypass grafting for stable coronary artery disease to remote preconditioning or "sham" intervention. The remote preconditioning is obtained by three cycles of 5 min inflation and 5 min deflation of a blood pressure cuff on the right arm. Postoperative course including myocardial enzymes profile will be analysed. Moreover, in the in-vitro arm the clinically preconditioned myocardium will be assessed for function, mitochondria structure, and mitochondria-dependent apoptosis. The informed consent of all patients is obtained before enrolment into the study by the investigator. The study conforms to the spirit and the letter of the declaration of Helsinki. In case the effect of remote preconditioning is not measurable in ex-vivo assessment, any future attempt at implementing this phenomenon in clinical

  14. Maximizers versus satisficers

    OpenAIRE

    Andrew M. Parker; Wandi Bruine de Bruin; Baruch Fischhoff

    2007-01-01

    Our previous research suggests that people reporting a stronger desire to maximize obtain worse life outcomes (Bruine de Bruin et al., 2007). Here, we examine whether this finding may be explained by the decision-making styles of self-reported maximizers. Expanding on Schwartz et al. (2002), we find that self-reported maximizers are more likely to show problematic decision-making styles, as evidenced by self-reports of less behavioral coping, greater dependence on others when making decisions...

  15. Maximal combustion temperature estimation

    International Nuclear Information System (INIS)

    Golodova, E; Shchepakina, E

    2006-01-01

    This work is concerned with the phenomenon of delayed loss of stability and the estimation of the maximal temperature of safe combustion. Using the qualitative theory of singular perturbations and canard techniques we determine the maximal temperature on the trajectories located in the transition region between the slow combustion regime and the explosive one. This approach is used to estimate the maximal temperature of safe combustion in multi-phase combustion models

  16. Ischemic preconditioning protects against gap junctional uncoupling in cardiac myofibroblasts.

    Science.gov (United States)

    Sundset, Rune; Cooper, Marie; Mikalsen, Svein-Ole; Ytrehus, Kirsti

    2004-01-01

    Ischemic preconditioning increases the heart's tolerance to a subsequent longer ischemic period. The purpose of this study was to investigate the role of gap junction communication in simulated preconditioning in cultured neonatal rat cardiac myofibroblasts. Gap junctional intercellular communication was assessed by Lucifer yellow dye transfer. Preconditioning preserved intercellular coupling after prolonged ischemia. An initial reduction in coupling in response to the preconditioning stimulus was also observed. This may protect neighboring cells from damaging substances produced during subsequent regional ischemia in vivo, and may preserve gap junctional communication required for enhanced functional recovery during subsequent reperfusion.

  17. Energy 21. Preconditions and results

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    In 1988 the Danish government adopted an action plan for the environment and sustainable development. In 1990, the energy aspects of this plan were embodied in Energy 2000 and, in 1993, in Energy 2000 follow-up. The objective is a 20% reduction of CO{sub 2} emissions by the year 2005, compared with the level in 1988. Various measures are therefore being taken as time passes to help achieve this objective. As part of the monitoring of developments in the energy sector, it is necessary to take stock from time to time and to assess the direction in which the sector is moving. The government has therefore drawn up a new energy action plan, Energy 21, both to ensure that the overall objectives in the current plan are actively followed up on and to look ahead at the possibilities for action after the year 2005. The Danish Energy Agency has previously carried out a number of analyses of the technological and behavioural possibilities for reducing energy consumption in the short and the long term, for improving the efficiency of energy supply installations, and for using new and sustainable energy technologies. The results of this work are described in the report Denmark`s Energy Futures. The calculations in the report itself and its appendices. The more detailed assumptions and a description of the methods of analysis etc. are given in Basis for Analysis of Denmark`s Energy Futures. This report contains the assumptions, a description of methods and some of the results of the work on Energy 21. (au)

  18. Maximally multipartite entangled states

    Science.gov (United States)

    Facchi, Paolo; Florio, Giuseppe; Parisi, Giorgio; Pascazio, Saverio

    2008-06-01

    We introduce the notion of maximally multipartite entangled states of n qubits as a generalization of the bipartite case. These pure states have a bipartite entanglement that does not depend on the bipartition and is maximal for all possible bipartitions. They are solutions of a minimization problem. Examples for small n are investigated, both analytically and numerically.

  19. Maximizers versus satisficers

    Directory of Open Access Journals (Sweden)

    Andrew M. Parker

    2007-12-01

    Full Text Available Our previous research suggests that people reporting a stronger desire to maximize obtain worse life outcomes (Bruine de Bruin et al., 2007. Here, we examine whether this finding may be explained by the decision-making styles of self-reported maximizers. Expanding on Schwartz et al. (2002, we find that self-reported maximizers are more likely to show problematic decision-making styles, as evidenced by self-reports of less behavioral coping, greater dependence on others when making decisions, more avoidance of decision making, and greater tendency to experience regret. Contrary to predictions, self-reported maximizers were more likely to report spontaneous decision making. However, the relationship between self-reported maximizing and worse life outcomes is largely unaffected by controls for measures of other decision-making styles, decision-making competence, and demographic variables.

  20. Tranexamic Acid Does Not Influence Cardioprotection by Ischemic Preconditioning and Remote Ischemic Preconditioning

    NARCIS (Netherlands)

    van Caster, Patrick; Eiling, Sandra; Boekholt, Yvonne; Behmenburg, Friederike; Dorsch, Marianne; Heinen, André; Hollmann, Markus W.; Huhn, Ragnar

    2018-01-01

    Prior studies have suggested that the antifibrinolytic drug aprotinin increases the infarct size after ischemia and reperfusion (I/R) and attenuates the effect of ischemic preconditioning (IPC). Aprotinin was replaced by tranexamic acid (TXA) in clinical practice. Here, we investigated whether TXA

  1. Parallel preconditioning techniques for sparse CG solvers

    Energy Technology Data Exchange (ETDEWEB)

    Basermann, A.; Reichel, B.; Schelthoff, C. [Central Institute for Applied Mathematics, Juelich (Germany)

    1996-12-31

    Conjugate gradient (CG) methods to solve sparse systems of linear equations play an important role in numerical methods for solving discretized partial differential equations. The large size and the condition of many technical or physical applications in this area result in the need for efficient parallelization and preconditioning techniques of the CG method. In particular for very ill-conditioned matrices, sophisticated preconditioner are necessary to obtain both acceptable convergence and accuracy of CG. Here, we investigate variants of polynomial and incomplete Cholesky preconditioners that markedly reduce the iterations of the simply diagonally scaled CG and are shown to be well suited for massively parallel machines.

  2. Preconditioning, postconditioning and their application to clinical cardiology.

    Science.gov (United States)

    Kloner, Robert A; Rezkalla, Shereif H

    2006-05-01

    Ischemic preconditioning is a well-established phenomenon first described in experimental preparations in which brief episodes of ischemia/reperfusion applied prior to a longer coronary artery occlusion reduce myocardial infarct size. There are ample correlates of ischemic preconditioning in the clinical realm. Preconditioning mimetic agents that stimulate the biochemical pathways of ischemic preconditioning and protect the heart without inducing ischemia have been examined in numerous experimental studies. However, despite the effectiveness of ischemic preconditioning and preconditioning mimetics for protecting ischemic myocardium, there are no preconditioning-based therapies that are routinely used in clinical medicine at the current time. Part of the problem is the need to administer therapy prior to the known ischemic event. Other issues are that percutaneous coronary intervention technology has advanced so far (with the development of stents and drug-eluting stents) that ischemic preconditioning or preconditioning mimetics have not been needed in most interventional cases. Recent clinical trials such as AMISTAD I and II (Acute Myocardial Infarction STudy of ADenosine) suggest that some preconditioning mimetics may reduce myocardial infarct size when given along with reperfusion or, as in the IONA trial, have benefit on clinical events when administered chronically in patients with known coronary artery disease. It is possible that some of the benefit described for adenosine in the AMISTAD 1 and 2 trials represents a manifestation of the recently described postconditioning phenomenon. It is probable that postconditioning--in which reperfusion is interrupted with brief coronary occlusions and reperfusion sequences--is more likely than preconditioning to be feasible as a clinical application to patients undergoing percutaneous coronary intervention for acute myocardial infarction.

  3. Least-squares reverse time migration with radon preconditioning

    KAUST Repository

    Dutta, Gaurav

    2016-09-06

    We present a least-squares reverse time migration (LSRTM) method using Radon preconditioning to regularize noisy or severely undersampled data. A high resolution local radon transform is used as a change of basis for the reflectivity and sparseness constraints are applied to the inverted reflectivity in the transform domain. This reflects the prior that for each location of the subsurface the number of geological dips is limited. The forward and the adjoint mapping of the reflectivity to the local Radon domain and back are done through 3D Fourier-based discrete Radon transform operators. The sparseness is enforced by applying weights to the Radon domain components which either vary with the amplitudes of the local dips or are thresholded at given quantiles. Numerical tests on synthetic and field data validate the effectiveness of the proposed approach in producing images with improved SNR and reduced aliasing artifacts when compared with standard RTM or LSRTM.

  4. Aerodynamic shape optimization using preconditioned conjugate gradient methods

    Science.gov (United States)

    Burgreen, Greg W.; Baysal, Oktay

    1993-01-01

    In an effort to further improve upon the latest advancements made in aerodynamic shape optimization procedures, a systematic study is performed to examine several current solution methodologies as applied to various aspects of the optimization procedure. It is demonstrated that preconditioned conjugate gradient-like methodologies dramatically decrease the computational efforts required for such procedures. The design problem investigated is the shape optimization of the upper and lower surfaces of an initially symmetric (NACA-012) airfoil in inviscid transonic flow and at zero degree angle-of-attack. The complete surface shape is represented using a Bezier-Bernstein polynomial. The present optimization method then automatically obtains supercritical airfoil shapes over a variety of freestream Mach numbers. Furthermore, the best optimization strategy examined resulted in a factor of 8 decrease in computational time as well as a factor of 4 decrease in memory over the most efficient strategies in current use.

  5. Galilean-invariant preconditioned central-moment lattice Boltzmann method without cubic velocity errors for efficient steady flow simulations

    Science.gov (United States)

    Hajabdollahi, Farzaneh; Premnath, Kannan N.

    2018-05-01

    conclusions are drawn from the analysis of the structure of the non-GI errors and the associated corrections, with particular emphasis on their dependence on the preconditioning parameter. The GI preconditioned central-moment LB method is validated for a number of complex flow benchmark problems and its effectiveness to achieve convergence acceleration and improvement in accuracy is demonstrated.

  6. Limb remote-preconditioning protects against focal ischemia in rats and contradicts the dogma of therapeutic time windows for preconditioning

    Science.gov (United States)

    Ren, Chuancheng; Gao, Xuwen; Steinberg, Gary K.; Zhao, Heng

    2009-01-01

    Remote ischemic preconditioning is an emerging concept for stroke treatment, but its protection against focal stroke has not been established. We tested whether remote preconditioning, performed in the ipsilateral hind limb, protects against focal stroke and explored its protective parameters. Stroke was generated by a permanent occlusion of the left distal middle cerebral artery (MCA) combined with a 30 minute occlusion of the bilateral common carotid arteries (CCA) in male rats. Limb preconditioning was generated by 5 or 15 minute occlusion followed with the same period of reperfusion of the left hind femoral artery, and repeated for 2 or 3 cycles. Infarct was measured 2 days later. The results showed that rapid preconditioning with 3 cycles of 15 minutes performed immediately before stroke reduced infarct size from 47.7±7.6% of control ischemia to 9.8±8.6%; at 2 cycles of 15 minutes, infarct was reduced to 24.7±7.3%; at 2 cycles of 5 minutes, infarct was not reduced. Delayed preconditioning with 3 cycles of 15 minutes conducted 2 days before stroke also reduced infarct to 23.0 ±10.9%, but with 2 cycles of 15 minutes it offered no protection. The protective effects at these two therapeutic time windows of remote preconditioning are consistent with those of conventional preconditioning, in which the preconditioning ischemia is induced in the brain itself. Unexpectedly, intermediate preconditioning with 3 cycles of 15 minutes performed 12 hours before stroke also reduced infarct to 24.7±4.7%, which contradicts the current dogma for therapeutic time windows for the conventional preconditioning that has no protection at this time point. In conclusion, remote preconditioning performed in one limb protected against ischemic damage after focal cerebral ischemia. PMID:18201834

  7. 40 CFR 86.532-78 - Vehicle preconditioning.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Vehicle preconditioning. 86.532-78... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.532-78 Vehicle preconditioning. (a) The vehicle...

  8. Helium induces preconditioning in human endothelium in vivo

    NARCIS (Netherlands)

    Smit, Kirsten F.; Oei, Gezina T. M. L.; Brevoord, Daniel; Stroes, Erik S.; Nieuwland, Rienk; Schlack, Wolfgang S.; Hollmann, Markus W.; Weber, Nina C.; Preckel, Benedikt

    2013-01-01

    Helium protects myocardium by inducing preconditioning in animals. We investigated whether human endothelium is preconditioned by helium inhalation in vivo. Forearm ischemia-reperfusion (I/R) in healthy volunteers (each group n = 10) was performed by inflating a blood pressure cuff for 20 min.

  9. High intensity interval training (HIIT) improves resting blood pressure, metabolic (MET) capacity and heart rate reserve without compromising cardiac function in sedentary aging men.

    Science.gov (United States)

    Grace, Fergal; Herbert, Peter; Elliott, Adrian D; Richards, Jo; Beaumont, Alexander; Sculthorpe, Nicholas F

    2017-05-13

    This study examined a programme of pre-conditioning exercise with subsequent high intensity interval training (HIIT) on blood pressure, echocardiography, cardiac strain mechanics and maximal metabolic (MET) capacity in sedentary (SED) aging men compared with age matched masters athletes (LEX). Using a STROBE compliant observational design, 39 aging male participants (SED; n=22, aged 62.7±5.2yrs) (LEX; n=17, aged=61.1±5.4yrs) were recruited to a study that necessitated three distinct assessment phases; enrolment (Phase A), following pre-conditioning exercise in SED (Phase B), then following 6weeks of HIIT performed once every five days by both groups before reassessment (Phase C). Hemodynamic, echocardiographic and cardiac strain mechanics were obtained at rest and maximal cardiorespiratory and chronotropic responses were obtained at each measurement phase. The training intervention improved systolic, mean arterial blood pressure, rate pressure product and heart rate reserve (each PHIIT. Echocardiography and cardiac strain measures were unremarkable apart from trivial increase to intra-ventricular septum diastole (IVSd) (PHIIT. A programme of preconditioning exercise with HIIT induces clinically relevant improvements in blood pressure, rate pressure product and encourages recovery of heart rate reserve in SED, while improving maximal MET capacity in both SED and LEX without inducing any pathological cardiovascular remodeling. These data add to the emerging repute of HIIT as a safe and promising exercise prescription to improve cardiovascular function and metabolic capacity in sedentary aging. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Strategy to maximize maintenance operation

    OpenAIRE

    Espinoza, Michael

    2005-01-01

    This project presents a strategic analysis to maximize maintenance operations in Alcan Kitimat Works in British Columbia. The project studies the role of maintenance in improving its overall maintenance performance. It provides strategic alternatives and specific recommendations addressing Kitimat Works key strategic issues and problems. A comprehensive industry and competitive analysis identifies the industry structure and its competitive forces. In the mature aluminium industry, the bargain...

  11. Effect of Different Preconditioning Regimens on the Expression Profile of Murine Adipose-Derived Stromal/Stem Cells

    Directory of Open Access Journals (Sweden)

    Patrick C. Baer

    2018-06-01

    Full Text Available Stem cell-based therapies require cells with a maximum regenerative capacity in order to support regeneration after tissue injury and organ failure. Optimization of this regenerative potential of mesenchymal stromal/stem cells (MSC or their conditioned medium by in vitro preconditioning regimens are considered to be a promising strategy to improve the release of regenerative factors. In the present study, MSC were isolated from inguinal adipose tissue (mASC from C57BL/6 mice, cultured, and characterized. Then, mASC were either preconditioned by incubation in a hypoxic environment (0.5% O2, or in normoxia in the presence of murine epidermal growth factor (EGF or tumor necrosis factor α (TNFα for 48 h. Protein expression was measured by a commercially available array. Selected factors were verified by PCR analysis. The expression of 83 out of 308 proteins (26.9% assayed was found to be increased after preconditioning with TNFα, whereas the expression of 61 (19.8% and 70 (22.7% proteins was increased after incubation with EGF or in hypoxia, respectively. Furthermore, we showed the proliferation-promoting effects of the preconditioned culture supernatants on injured epithelial cells in vitro. Our findings indicate that each preconditioning regimen tested induced an individual expression profile with a wide variety of factors, including several growth factors and cytokines, and therefore may enhance the regenerative potential of mASC for cell-based therapies.

  12. Preconditioned augmented Lagrangian formulation for nearly incompressible cardiac mechanics.

    Science.gov (United States)

    Campos, Joventino Oliveira; Dos Santos, Rodrigo Weber; Sundnes, Joakim; Rocha, Bernardo Martins

    2018-04-01

    Computational modeling of the heart is a subject of substantial medical and scientific interest, which may contribute to increase the understanding of several phenomena associated with cardiac physiological and pathological states. Modeling the mechanics of the heart have led to considerable insights, but it still represents a complex and a demanding computational problem, especially in a strongly coupled electromechanical setting. Passive cardiac tissue is commonly modeled as hyperelastic and is characterized by quasi-incompressible, orthotropic, and nonlinear material behavior. These factors are known to be very challenging for the numerical solution of the model. The near-incompressibility is known to cause numerical issues such as the well-known locking phenomenon and ill-conditioning of the stiffness matrix. In this work, the augmented Lagrangian method is used to handle the nearly incompressible condition. This approach can potentially improve computational performance by reducing the condition number of the stiffness matrix and thereby improving the convergence of iterative solvers. We also improve the performance of iterative solvers by the use of an algebraic multigrid preconditioner. Numerical results of the augmented Lagrangian method combined with a preconditioned iterative solver for a cardiac mechanics benchmark suite are presented to show its improved performance. Copyright © 2017 John Wiley & Sons, Ltd.

  13. Protective role of vitamin E preconditioning of human dermal fibroblasts against thermal stress in vitro.

    Science.gov (United States)

    Butt, Hira; Mehmood, Azra; Ali, Muhammad; Tasneem, Saba; Anjum, Muhammad Sohail; Tarar, Moazzam N; Khan, Shaheen N; Riazuddin, Sheikh

    2017-09-01

    Oxidative microenvironment of burnt skin restricts the outcome of cell based therapies of thermal skin injuries. The aim of this study was to precondition human dermal fibroblasts with an antioxidant such as vitamin E to improve their survival and therapeutic abilities in heat induced oxidative in vitro environment. Fibroblasts were treated with 100μM vitamin E for 24h at 37°C followed by heat shock for 10min at 51°C in fresh serum free medium. Preconditioning with vitamin E reduced cell injury as demonstrated by decreased expression of annexin-V, cytochrome p450 (CYP450) mediated oxidative reactions, senescence and release of lactate dehydrogenase (LDH) accomplished by down-regulated expression of pro-apoptotic BAX gene. Vitamin E preconditioned cells exhibited remarkable improvement in cell viability, release of paracrine factors such as epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), stromal derived factor-1alpha (SDF-1α) and also showed significantly up-regulated levels of PCNA, VEGF, BCL-XL, FGF7, FGF23, FLNβ and Col7α genes presumably through activation of phosphatidylinositol 3-kinase (PI3-K)/Akt pathway. The results suggest that pretreatment of fibroblasts with vitamin E prior to transplantation in burnt skin speeds up the wound healing process by improving the antioxidant scavenging responses in oxidative environment of transplanted burn wounds. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Guinea pig maximization test

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner

    1985-01-01

    Guinea pig maximization tests (GPMT) with chlorocresol were performed to ascertain whether the sensitization rate was affected by minor changes in the Freund's complete adjuvant (FCA) emulsion used. Three types of emulsion were evaluated: the oil phase was mixed with propylene glycol, saline...

  15. Tri-maximal vs. bi-maximal neutrino mixing

    International Nuclear Information System (INIS)

    Scott, W.G

    2000-01-01

    It is argued that data from atmospheric and solar neutrino experiments point strongly to tri-maximal or bi-maximal lepton mixing. While ('optimised') bi-maximal mixing gives an excellent a posteriori fit to the data, tri-maximal mixing is an a priori hypothesis, which is not excluded, taking account of terrestrial matter effects

  16. Realization of preconditioned Lanczos and conjugate gradient algorithms on optical linear algebra processors.

    Science.gov (United States)

    Ghosh, A

    1988-08-01

    Lanczos and conjugate gradient algorithms are important in computational linear algebra. In this paper, a parallel pipelined realization of these algorithms on a ring of optical linear algebra processors is described. The flow of data is designed to minimize the idle times of the optical multiprocessor and the redundancy of computations. The effects of optical round-off errors on the solutions obtained by the optical Lanczos and conjugate gradient algorithms are analyzed, and it is shown that optical preconditioning can improve the accuracy of these algorithms substantially. Algorithms for optical preconditioning and results of numerical experiments on solving linear systems of equations arising from partial differential equations are discussed. Since the Lanczos algorithm is used mostly with sparse matrices, a folded storage scheme to represent sparse matrices on spatial light modulators is also described.

  17. Convergence Analysis of the Preconditioned Group Splitting Methods in Boundary Value Problems

    Directory of Open Access Journals (Sweden)

    Norhashidah Hj. Mohd Ali

    2012-01-01

    Full Text Available The construction of a specific splitting-type preconditioner in block formulation applied to a class of group relaxation iterative methods derived from the centred and rotated (skewed finite difference approximations has been shown to improve the convergence rates of these methods. In this paper, we present some theoretical convergence analysis on this preconditioner specifically applied to the linear systems resulted from these group iterative schemes in solving an elliptic boundary value problem. We will theoretically show the relationship between the spectral radiuses of the iteration matrices of the preconditioned methods which affects the rate of convergence of these methods. We will also show that the spectral radius of the preconditioned matrices is smaller than that of their unpreconditioned counterparts if the relaxation parameter is in a certain optimum range. Numerical experiments will also be presented to confirm the agreement between the theoretical and the experimental results.

  18. Psychological preconditions of game activity development in the early childhood

    OpenAIRE

    Valeriya Spitsyna; Ekaterina Saraykina

    2013-01-01

    The article is devoted for detection the psychological preconditions of game activity development at early age and interrelation of game formation with the development of subject actions, informative activity and procedural game.

  19. Association of Exercise Preconditioning With Immediate Cardioprotection: A Review.

    NARCIS (Netherlands)

    Thijssen, D.H.J.; Redington, A.; George, K.P.; Hopman, M.T.E.; Jones, H.

    2018-01-01

    Importance: Exercise reduces the risk of cardiovascular events, including through an underrecognized, clinically useful form of acute cardioprotection accessible after a single episode of exercise, which is called cardiovascular preconditioning. Observations: Preclinical evidence shows that 1 to 3

  20. Nonlinear Multiplicative Schwarz Preconditioning in Natural Convection Cavity Flow

    KAUST Repository

    Liu, Lulu; Zhang, Wei; Keyes, David E.

    2017-01-01

    A natural convection cavity flow problem is solved using nonlinear multiplicative Schwarz preconditioners, as a Gauss-Seidel-like variant of additive Schwarz preconditioned inexact Newton (ASPIN). The nonlinear preconditioning extends the domain of convergence of Newton’s method to high Rayleigh numbers. Convergence performance varies widely with respect to different groupings of the fields of this multicomponent problem, and with respect to different orderings of the groupings.

  1. Decentralisation in developing countries: preconditions for successful implementation

    Directory of Open Access Journals (Sweden)

    Yasin Olum

    2014-07-01

    Full Text Available Decentralisation has been implemented and is being implemented in many developing countries without much success. Although several unique factors inhibit the implementation of decentralisation in individual countries, the paper argues that there are six pre-conditions that these countries should fulfill before decentralisation can be successfully implemented. These preconditions are: institutional mechanisms; creation of spaces for participation; political will and civil will; capacity development at the local level; careful implementation; and democratic governance.

  2. Nonlinear Multiplicative Schwarz Preconditioning in Natural Convection Cavity Flow

    KAUST Repository

    Liu, Lulu

    2017-03-17

    A natural convection cavity flow problem is solved using nonlinear multiplicative Schwarz preconditioners, as a Gauss-Seidel-like variant of additive Schwarz preconditioned inexact Newton (ASPIN). The nonlinear preconditioning extends the domain of convergence of Newton’s method to high Rayleigh numbers. Convergence performance varies widely with respect to different groupings of the fields of this multicomponent problem, and with respect to different orderings of the groupings.

  3. Ukraine Agricultural Land Market Formation Preconditions

    Directory of Open Access Journals (Sweden)

    Evgen Dankevych

    2017-01-01

    Full Text Available The theoretical land relations reforming principles were reviewed.Land relations in agriculture transformation process was studied. The land use features were detected and agricultural land use efficiency analysis was conducted.Ukraine land market formation research problems results have been shown. It was established that private land ownership institution ambiguous attitude, rent relations deformation, lack of the property rights ensure mechanism inhibit the land market development. Sociological research of Ukrainian Polesie region to determine the prerequisites for agricultural land marketformation preconditions has been conducted. 787 respondents from Zhytomyr, Rivne and Volyn regions were interviewed. Land shares owners age structure, their distribution by education level, their employment, land shares owners and agricultural enterprises executives to the agricultural land sale moratorium cancellation attitudes, land purchase financial resources, directions of Ukrainian Polissya region land shares use, shares owners land issues level of awareness have been determined during the research. Was substantiated that agricultural land market turnover includes not only land sale moratorium cancellation but also the adoption of the legislative framework and the appropriate infrastructure development, one of the key elements of which is land relations regulation specialized state agency – State Land Bank.

  4. Hypoxia preconditioning of mesenchymal stromal cells enhances PC3 cell lymphatic metastasis accompanied by VEGFR-3/CCR7 activation.

    Science.gov (United States)

    Huang, Xin; Su, Kunkai; Zhou, Limin; Shen, Guofang; Dong, Qi; Lou, Yijia; Zheng, Shu

    2013-12-01

    Mesenchymal stromal cells (MSCs) in bone marrow may enhance tumor metastases through the secretion of chemokines. MSCs have been reported to home toward the hypoxic tumor microenvironment in vivo. In this study, we investigated prostate cancer PC3 cell behavior under the influence of hypoxia preconditioned MSCs and explored the related mechanism of prostate cancer lymphatic metastases in mice. Transwell assays revealed that VEGF-C receptor, VEGFR-3, as well as chemokine CCL21 receptor, CC chemokine receptor 7 (CCR7), were responsible for the migration of PC3 cells toward hypoxia preconditioned MSCs. Knock-in Ccr7 in PC3 cells also improved cell migration in vitro. Furthermore, when PC3 cells were labeled using the hrGfp-lentiviral vector, and were combined with hypoxia preconditioned MSCs for xenografting, it resulted in an enhancement of lymph node metastases accompanied by up-regulation of VEGFR-3 and CCR7 in primary tumors. Both PI3K/Akt/IκBα and JAK2/STAT3 signaling pathways were activated in xenografts in the presence of hypoxia-preconditioned MSCs. Unexpectedly, the p-VEGFR-2/VEGFR-2 ratio was attenuated accompanied by decreased JAK1 expression, indicating a switching-off of potential vascular signal within xenografts in the presence of hypoxia-preconditioned MSCs. Unlike results from other studies, VEGF-C maintained a stable expression in both conditions, which indicated that hypoxia preconditioning of MSCs did not influence VEGF-C secretion. Our results provide the new insights into the functional molecular events and signalings influencing prostate tumor metastases, suggesting a hopeful diagnosis and treatment in new approaches. © 2013 Wiley Periodicals, Inc.

  5. The GLP-1 analogue liraglutide improves first-phase insulin secretion and maximal beta-cell secretory capacity over 14 weeks of therapy in subjects with Type 2 diabetes

    DEFF Research Database (Denmark)

    Madsbad, Sten; Vilsbøll, Tina; Brock, Birgitte

    Aims: We investigated the clinical effect of liraglutide, a long- acting GLP-1 analogue, on insulin secretion in Type 2 diabetes. Methods: Thirty-nine subjects (28 completed) from a randomised trial received a hyperglycaemic clamp (20 mM) with intravenous arginine stimulation, and an insulin...... group. Conclusion: In subjects with Type 2 diabetes, 14 weeks’ once-daily liraglutide (1.25 and 1.9 mg/day) markedly improves beta-cell function, significantly increases first-phase insulin secretion and maximal beta-cell secretory capacity....

  6. Performance excellence: using Lean Six Sigma tools to improve the US Army behavioral health surveillance process, boost team morale, and maximize value to customers and stakeholders.

    Science.gov (United States)

    Watkins, Eren Youmans; Kemeter, Dave M; Spiess, Anita; Corrigan, Elizabeth; Kateley, Keri; Wills, John V; Mancha, Brent Edward; Nichols, Jerrica; Bell, Amy Millikan

    2014-01-01

    Lean Six Sigma (LSS) is a process improvement, problem-solving methodology used in business and manufacturing to improve the speed, quality, and cost of products. LSS can also be used to improve knowledge-based products integral to public health surveillance. An LSS project by the Behavioral Social Health Outcomes Program of the Army Institute of Public Health reduced the number of labor hours spent producing the routine surveillance of suicidal behavior publication. At baseline, the total number of labor hours was 448; after project completion, total labor hours were 199. Based on customer feedback, publication production was reduced from quarterly to annually. Process improvements enhanced group morale and established best practices in the form of standard operating procedures and business rules to ensure solutions are sustained. LSS project participation also fostered a change in the conceptualization of tasks and projects. These results demonstrate that LSS can be used to inform the public health process and should be considered a viable method of improving knowledge-based products and processes.

  7. The protective effect of ischemic preconditioning on rat testis

    Directory of Open Access Journals (Sweden)

    Ciralik Harun

    2007-12-01

    Full Text Available Abstract Background It has been demonstrated that brief episodes of sublethal ischemia-reperfusion, so-called ischemic preconditioning, provide powerful tissue protection in different tissues such as heart, brain, skeletal muscle, lung, liver, intestine, kidney, retina, and endothelial cells. Although a recent study has claimed that there are no protective effects of ischemic preconditioning in rat testis, the protective effects of ischemic preconditioning on testicular tissue have not been investigated adequately. The present study was thus planned to investigate whether ischemic preconditioning has a protective effect on testicular tissue. Methods Rats were divided into seven groups that each contained seven rats. In group 1 (control group, only unilateral testicular ischemia was performed by creating a testicular torsion by a 720 degree clockwise rotation for 180 min. In group 2, group 3, group 4, group 5, group 6, and group 7, unilateral testicular ischemia was performed for 180 min following different periods of ischemic preconditioning. The ischemic preconditioning periods were as follows: 10 minutes of ischemia with 10 minutes of reperfusion in group 2; 20 minutes of ischemia with 10 minutes of reperfusion in group 3; 30 minutes of ischemia with 10 minutes of reperfusion in group 4; multiple preconditioning periods were used (3 × 10 min early phase transient ischemia with 10 min reperfusion in all episodes in group 5; multiple preconditioning periods were used (5, 10, and 15 min early phase transient ischemia with 10 min reperfusion in all episodes in group 6; and, multiple preconditioning periods were used (10, 20, and 30 min early phase transient ischemia with 10 min reperfusion in all episodes in group 7. After the ischemic protocols were carried out, animals were sacrificed by cervical dislocation and testicular tissue samples were taken for biochemical measurements (protein, malondialdehyde, nitric oxide and histological examination

  8. Nonlinear Preconditioning and its Application in Multicomponent Problems

    KAUST Repository

    Liu, Lulu

    2015-12-07

    The Multiplicative Schwarz Preconditioned Inexact Newton (MSPIN) algorithm is presented as a complement to Additive Schwarz Preconditioned Inexact Newton (ASPIN). At an algebraic level, ASPIN and MSPIN are variants of the same strategy to improve the convergence of systems with unbalanced nonlinearities; however, they have natural complementarity in practice. MSPIN is naturally based on partitioning of degrees of freedom in a nonlinear PDE system by field type rather than by subdomain, where a modest factor of concurrency can be sacrificed for physically motivated convergence robustness. ASPIN, originally introduced for decompositions into subdomains, is natural for high concurrency and reduction of global synchronization. The ASPIN framework, as an option for the outermost solver, successfully handles strong nonlinearities in computational fluid dynamics, but is barely explored for the highly nonlinear models of complex multiphase flow with capillarity, heterogeneity, and complex geometry. In this dissertation, the fully implicit ASPIN method is demonstrated for a finite volume discretization based on incompressible two-phase reservoir simulators in the presence of capillary forces and gravity. Numerical experiments show that the number of global nonlinear iterations is not only scalable with respect to the number of processors, but also significantly reduced compared with the standard inexact Newton method with a backtracking technique. Moreover, the ASPIN method, in contrast with the IMPES method, saves overall execution time because of the savings in timestep size. We consider the additive and multiplicative types of inexact Newton algorithms in the field-split context, and we augment the classical convergence theory of ASPIN for the multiplicative case. Moreover, we provide the convergence analysis of the MSPIN algorithm. Under suitable assumptions, it is shown that MSPIN is locally convergent, and desired superlinear or even quadratic convergence can be

  9. Key cognitive preconditions for the evolution of language.

    Science.gov (United States)

    Donald, Merlin

    2017-02-01

    Languages are socially constructed systems of expression, generated interactively in social networks, which can be assimilated by the individual brain as it develops. Languages co-evolved with culture, reflecting the changing complexity of human culture as it acquired the properties of a distributed cognitive system. Two key preconditions set the stage for the evolution of such cultures: a very general ability to rehearse and refine skills (evident early in hominin evolution in toolmaking), and the emergence of material culture as an external (to the brain) memory record that could retain and accumulate knowledge across generations. The ability to practice and rehearse skill provided immediate survival-related benefits in that it expanded the physical powers of early hominins, but the same adaptation also provided the imaginative substrate for a system of "mimetic" expression, such as found in ritual and pantomime, and in proto-words, which performed an expressive function somewhat like the home signs of deaf non-signers. The hominid brain continued to adapt to the increasing importance and complexity of culture as human interactions with material culture became more complex; above all, this entailed a gradual expansion in the integrative systems of the brain, especially those involved in the metacognitive supervision of self-performances. This supported a style of embodied mimetic imagination that improved the coordination of shared activities such as fire tending, but also in rituals and reciprocal mimetic games. The time-depth of this mimetic adaptation, and its role in both the construction and acquisition of languages, explains the importance of mimetic expression in the media, religion, and politics. Spoken language evolved out of voco-mimesis, and emerged long after the more basic abilities needed to refine skill and share intentions, probably coinciding with the common ancestor of sapient humans. Self-monitoring and self-supervised practice were necessary

  10. Functional recovery in rat spinal cord injury induced by hyperbaric oxygen preconditioning.

    Science.gov (United States)

    Lu, Pei-Gang; Hu, Sheng-Li; Hu, Rong; Wu, Nan; Chen, Zhi; Meng, Hui; Lin, Jiang-Kai; Feng, Hua

    2012-12-01

    It is a common belief that neurosurgical interventions can cause inevitable damage resulting from the procedure itself in surgery especially for intramedullary spinal cord tumors. The present study was designed to examine if hyperbaric oxygen preconditioning (HBO-PC) was neuroprotective against surgical injuries using a rat model of spinal cord injury (SCI). Sprague-Dawley rats were randomly divided into three groups: HBO-PC group, hypobaric hypoxic preconditioning (HH-PC) control group, and normobaric control group. All groups were subjected to SCI by weight drop device. Rats from each group were examined for neurological behavior and electrophysiological function. Tissue sections were analyzed by using immunohistochemistry, TdT-mediated dUTP-biotin nick end labeling, and axonal tract tracing. Significant neurological deficits were observed after SCI and HBO-PC and HH-PC improved neurological deficits 1 week post-injury. The latencies of motor-evoked potential and somatosensory-evoked potential were significantly delayed after SCI, which was attenuated by HBO-PC and HH-PC. Compared with normobaric control group, pretreatment with HBO and hypobaric hypoxia significantly reduced the number of TdT-mediated dUTP-biotin nick end labeling-positive cells, and increased nestin-positive cells. HBO-PC and HH-PC enhanced axonal growth after SCI. In conclusion, preconditioning with HBO and hypobaric hypoxia can facilitate functional recovery and suppress cell apoptosis after SCI and may prove to be a useful preventive strategy to neurosurgical SCI.

  11. Audiovisual preconditioning enhances the efficacy of an anatomical dissection course: A randomised study.

    Science.gov (United States)

    Collins, Anne M; Quinlan, Christine S; Dolan, Roisin T; O'Neill, Shane P; Tierney, Paul; Cronin, Kevin J; Ridgway, Paul F

    2015-07-01

    The benefits of incorporating audiovisual materials into learning are well recognised. The outcome of integrating such a modality in to anatomical education has not been reported previously. The aim of this randomised study was to determine whether audiovisual preconditioning is a useful adjunct to learning at an upper limb dissection course. Prior to instruction participants completed a standardised pre course multiple-choice questionnaire (MCQ). The intervention group was subsequently shown a video with a pre-recorded commentary. Following initial dissection, both groups completed a second MCQ. The final MCQ was completed at the conclusion of the course. Statistical analysis confirmed a significant improvement in the performance in both groups over the duration of the three MCQs. The intervention group significantly outperformed their control group counterparts immediately following audiovisual preconditioning and in the post course MCQ. Audiovisual preconditioning is a practical and effective tool that should be incorporated in to future course curricula to optimise learning. Level of evidence This study appraises an intervention in medical education. Kirkpatrick Level 2b (modification of knowledge). Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  12. MAXIM: The Blackhole Imager

    Science.gov (United States)

    Gendreau, Keith; Cash, Webster; Gorenstein, Paul; Windt, David; Kaaret, Phil; Reynolds, Chris

    2004-01-01

    The Beyond Einstein Program in NASA's Office of Space Science Structure and Evolution of the Universe theme spells out the top level scientific requirements for a Black Hole Imager in its strategic plan. The MAXIM mission will provide better than one tenth of a microarcsecond imaging in the X-ray band in order to satisfy these requirements. We will overview the driving requirements to achieve these goals and ultimately resolve the event horizon of a supermassive black hole. We will present the current status of this effort that includes a study of a baseline design as well as two alternative approaches.

  13. Prolonged preconditioning with natural honey against myocardial infarction injuries.

    Science.gov (United States)

    Eteraf-Oskouei, Tahereh; Shaseb, Elnaz; Ghaffary, Saba; Najafi, Moslem

    2013-07-01

    Potential protective effects of prolonged preconditioning with natural honey against myocardial infarction were investigated. Male Wistar rats were pre-treated with honey (1%, 2% and 4%) for 45 days then their hearts were isolated and mounted on a Langendorff apparatus and perfused with a modified Krebs-Henseleit solution during 30 min regional ischemia fallowed by 120 min reperfusion. Two important indexes of ischemia-induced damage (infarction size and arrhythmias) were determined by computerized planimetry and ECG analysis, respectively. Honey (1% and 2%) reduced infarct size from 23±3.1% (control) to 9.7±2.4 and 9.5±2.3%, respectively (Phoney (1%) significantly reduced (PHoney (1% and 2%) also significantly decreased number of ventricular ectopic beats (VEBs). In addition, incidence and duration of reversible ventricular fibrillation (Rev VF) were lowered by honey 2% (Phoney produced significant reduction in the incidences of VT, total and Rev VF, duration and number of VT. The results showed cardioprotective effects of prolonged pre-treatment of rats with honey following myocardial infarction. Maybe, the existence of antioxidants and energy sources (glucose and fructose) in honey composition and improvement of hemodynamic functions may involve in those protective effects.

  14. High intensity interval training improves VO2peak, maximal lactate production, time trial and competition performance in 9-11 year old swimmers

    OpenAIRE

    Sperlich, Billy; Zinner, Christoph; Helleman, Ilka; Kjendlie, Per-Ludvik; Holmberg, H. C.; Mester, Joachim

    2010-01-01

    Open Access - This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the source is credited. Training volume in swimming is usually very high when compared to the relatively short competition time. High-intensity interval training (HIIT) has been demonstrated to improve performance in a relatively short training period. The main purpose of the present s...

  15. Improvement of Upper Extremity Deficit after Constraint-Induced Movement Therapy Combined with and without Preconditioning Stimulation Using Dual-hemisphere Transcranial Direct Current Stimulation and Peripheral Neuromuscular Stimulation in Chronic Stroke Patients: A Pilot Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Takashi Takebayashi

    2017-10-01

    Full Text Available In this study, we investigated the effects of dual-hemisphere transcranial direct current stimulation (dual-tDCS of both the affected (anodal tDCS and non-affected (cathodal tDCS primary motor cortex, combined with peripheral neuromuscular electrical stimulation (PNMES, on the effectiveness of constraint-induced movement therapy (CIMT as a neurorehabilitation intervention in chronic stroke. We conducted a randomized controlled trial of feasibility, with a single blind assessor, with patients recruited from three outpatient clinics. Twenty chronic stroke patients were randomly allocated to the control group, receiving conventional CIMT, or the intervention group receiving dual-tDCS combined with PNMES before CIMT. Patients in the treatment group first underwent a 20-min period of dual-tDCS, followed immediately by PNMES, and subsequent CIMT for 2 h. Patients in the control group only received CIMT (with no pretreatment stimulation. All patients underwent two CIMT sessions, one in the morning and one in the afternoon, each lasting 2 h, for a total of 4 h of CIMT per day. Upper extremity function was assessed using the Fugl-Meyer Assessment (primary outcome, as well as the amount of use (AOU and quality of movement (QOM scores, obtained via the Motor Activity Log (secondary outcome. Nineteen patients completed the study, with one patient withdrawing after allocation. Compared to the control group, the treatment improvement in upper extremity function and AOU was significantly greater in the treatment than control group (change in upper extremity score, 9.20 ± 4.64 versus 4.56 ± 2.60, respectively, P < 0.01, η2 = 0.43; change in AOU score, 1.10 ± 0.65 versus 0.62 ± 0.85, respectively, P = 0.02, η2 = 0.52. There was no significant effect of the intervention on the QOM between the intervention and control groups (change in QOM score, 1.00 ± 0.62 versus 0.71 ± 0.72, respectively, P = 0.07, η2

  16. Evaluation of bioleaching column test of sulphide copper ore and copper concentrate using preconditioned surface

    Directory of Open Access Journals (Sweden)

    Videla Leiva Alvaro

    2016-01-01

    Full Text Available Bacterial activity can be related to the presence of Fe+3 in the solution, which drives copper oxidation during the secondary copper low grade sulfide ore leaching process. The present work evaluates improvements in kinetics of leaching when ferroxidans are preconditioned in an inert surface helping to build a biofilm which improves metabolism of the colony. The present work shows evaluation using laboratory columns to perform bioleaching during a 30 days period under three conditions: a base column with no inert surface, a column with loofa available for bacterial growth and conditioning, and finally a column with the loofa surface ground and distributed in the column among the particles.

  17. [Anaesthetic-induced myocardial preconditioning: fundamental basis and clinical implications].

    Science.gov (United States)

    Chiari, P; Bouvet, F; Piriou, V

    2005-04-01

    Volatile halogenated anaesthetics offer a myocardial protection when they are administrated before a myocardial ischaemia. Cellular mechanisms involved in anaesthetic preconditioning are now better understood. The objectives of this review are to understand the anaesthetic-induced preconditioning underlying mechanisms and to know the clinical implications. References were obtained from PubMed data bank (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi) using the following keywords: volatile anaesthetic, isoflurane, halothane, sevoflurane, desflurane, preconditioning, protection, myocardium. Ischaemic preconditioning (PC) is a myocardial endogenous protection against ischaemia. It has been described as one or several short ischaemia before a sustained ischemia. These short ischaemia trigger a protective signal against this longer ischaemia. An ischemic organ is able to precondition a remote organ. It is possible to replace the short ischaemia by a preadministration of halogenated volatile anaesthetic with the same protective effect, this is called anaesthetic PC (APC). APC and ischaemic PC share similar underlying biochemical mechanisms including protein kinase C, tyrosine kinase activation and mitochondrial and sarcolemnal K(ATP) channels opening. All halogenated anaesthetics can produce an anaesthetic PC effect. Myocardial protection during reperfusion, after the long ischaemia, has been shown by successive short ischaemia or volatile anaesthetic administration, this is called postconditioning. Ischaemic PC has been described in humans in 1993. Clinical studies in human cardiac surgery have shown the possibility of anaesthetic PC with volatile anaesthetics. These studies have shown a decrease of postoperative troponin in patient receiving halogenated anaesthetics.

  18. Operator-Based Preconditioning of Stiff Hyperbolic Systems

    International Nuclear Information System (INIS)

    Reynolds, Daniel R.; Samtaney, Ravi; Woodward, Carol S.

    2009-01-01

    We introduce an operator-based scheme for preconditioning stiff components encountered in implicit methods for hyperbolic systems of partial differential equations posed on regular grids. The method is based on a directional splitting of the implicit operator, followed by a characteristic decomposition of the resulting directional parts. This approach allows for solution to any number of characteristic components, from the entire system to only the fastest, stiffness-inducing waves. We apply the preconditioning method to stiff hyperbolic systems arising in magnetohydro- dynamics and gas dynamics. We then present numerical results showing that this preconditioning scheme works well on problems where the underlying stiffness results from the interaction of fast transient waves with slowly-evolving dynamics, scales well to large problem sizes and numbers of processors, and allows for additional customization based on the specific problems under study

  19. The Role of Ionospheric Outflow Preconditioning in Determining Storm Geoeffectiveness

    Science.gov (United States)

    Welling, D. T.; Liemohn, M. W.; Ridley, A. J.

    2012-12-01

    It is now well accepted that ionospheric outflow plays an important role in the development of the plasma sheet and ring current during geomagnetic storms. Furthermore, even during quiet times, ionospheric plasma populates the magnetospheric lobes, producing a reservoir of hydrogen and oxygen ions. When the Interplanetary Magnetic Field (IMF) turns southward, this reservoir is connected to the plasma sheet and ring current through magnetospheric convection. Hence, the conditions of the ionosphere and magnetospheric lobes leading up to magnetospheric storm onset have important implications for storm development. Despite this, there has been little research on this preconditioning; most global simulations begin just before storm onset, neglecting preconditioning altogether. This work explores the role of preconditioning in determining the geoeffectiveness of storms using a coupled global model system. A model of ionospheric outflow (the Polar Wind Outflow Model, PWOM) is two-way coupled to a global magnetohydrodynamic model (the Block-Adaptive Tree Solar wind Roe-type Upwind Scheme, BATS-R-US), which in turn drives a ring current model (the Ring current Atmosphere interactions Model, RAM). This unique setup is used to simulate an idealized storm. The model is started at many different times, from 1 hour before storm onset to 12 hours before. The effects of storm preconditioning are examined by investigating the total ionospheric plasma content in the lobes just before onset, the total ionospheric contribution in the ring current just after onset, and the effects on Dst, magnetic elevation angle at geosynchronous, and total ring current energy density. This experiment is repeated for different solar activity levels as set by F10.7 flux. Finally, a synthetic double-dip storm is constructed to see how two closely spaced storms affect each other by changing the preconditioning environment. It is found that preconditioning of the magnetospheric lobes via ionospheric

  20. Prime Time Light Exposures Do Not Seem to Improve Maximal Physical Performance in Male Elite Athletes, but Enhance End-Spurt Performance

    Directory of Open Access Journals (Sweden)

    Arno Schmidt-Trucksäss

    2017-05-01

    Full Text Available Many sports competitions take place during television prime time, a time of the day when many athletes have already exceeded their time of peak performance. We assessed the effect of different light exposure modalities on physical performance and melatonin levels in athletes during prime time. Seventy-two young, male elite athletes with a median (interquartile range age of 23 (21; 29 years and maximum oxygen uptake (VO2max of 63 (58; 66 ml/kg/min were randomly assigned to three different light exposure groups: bright light (BRIGHT, blue monochromatic light (BLUE, and control light (CONTROL. Each light exposure lasted 60 min and was scheduled to start 17 h after each individual's midpoint of sleep (median time: 9:17 pm. Immediately after light exposure, a 12-min time trial was performed on a bicycle ergometer. The test supervisor and participants were blinded to the light condition each participant was exposed to. The median received light intensities and peak wavelengths (photopic lx/nm measured at eye level were 1319/545 in BRIGHT, 203/469 in BLUE, and 115/545 in CONTROL. In a multivariate analysis adjusted for individual VO2max, total work performed in 12 min did not significantly differ between the three groups. The amount of exposure to non-image forming light was positively associated with the performance gain during the time trial, defined as the ratio of the work performed in the first and last minute of the time trial, and with stronger melatonin suppression. Specifically, a tenfold increase in the exposure to melanopic light was associated with a performance gain of 8.0% (95% confidence interval: 2.6, 13.3; P = 0.004 and a melatonin decrease of −0.9 pg/ml (95% confidence interval: −1.5, −0.3; P = 0.006. Exposure to bright or blue light did not significantly improve maximum cycling performance in a 12-min all-out time trial. However, it is noteworthy that the estimated difference of 4.1 kJ between BRIGHT and CONTROL might represent

  1. Prime Time Light Exposures Do Not Seem to Improve Maximal Physical Performance in Male Elite Athletes, but Enhance End-Spurt Performance

    Science.gov (United States)

    Knaier, Raphael; Schäfer, Juliane; Rossmeissl, Anja; Klenk, Christopher; Hanssen, Henner; Höchsmann, Christoph; Cajochen, Christian; Schmidt-Trucksäss, Arno

    2017-01-01

    Many sports competitions take place during television prime time, a time of the day when many athletes have already exceeded their time of peak performance. We assessed the effect of different light exposure modalities on physical performance and melatonin levels in athletes during prime time. Seventy-two young, male elite athletes with a median (interquartile range) age of 23 (21; 29) years and maximum oxygen uptake (VO2max) of 63 (58; 66) ml/kg/min were randomly assigned to three different light exposure groups: bright light (BRIGHT), blue monochromatic light (BLUE), and control light (CONTROL). Each light exposure lasted 60 min and was scheduled to start 17 h after each individual's midpoint of sleep (median time: 9:17 pm). Immediately after light exposure, a 12-min time trial was performed on a bicycle ergometer. The test supervisor and participants were blinded to the light condition each participant was exposed to. The median received light intensities and peak wavelengths (photopic lx/nm) measured at eye level were 1319/545 in BRIGHT, 203/469 in BLUE, and 115/545 in CONTROL. In a multivariate analysis adjusted for individual VO2max, total work performed in 12 min did not significantly differ between the three groups. The amount of exposure to non-image forming light was positively associated with the performance gain during the time trial, defined as the ratio of the work performed in the first and last minute of the time trial, and with stronger melatonin suppression. Specifically, a tenfold increase in the exposure to melanopic light was associated with a performance gain of 8.0% (95% confidence interval: 2.6, 13.3; P = 0.004) and a melatonin decrease of −0.9 pg/ml (95% confidence interval: −1.5, −0.3; P = 0.006). Exposure to bright or blue light did not significantly improve maximum cycling performance in a 12-min all-out time trial. However, it is noteworthy that the estimated difference of 4.1 kJ between BRIGHT and CONTROL might represent an

  2. Fourier analysis of finite element preconditioned collocation schemes

    Science.gov (United States)

    Deville, Michel O.; Mund, Ernest H.

    1990-01-01

    The spectrum of the iteration operator of some finite element preconditioned Fourier collocation schemes is investigated. The first part of the paper analyses one-dimensional elliptic and hyperbolic model problems and the advection-diffusion equation. Analytical expressions of the eigenvalues are obtained with use of symbolic computation. The second part of the paper considers the set of one-dimensional differential equations resulting from Fourier analysis (in the tranverse direction) of the 2-D Stokes problem. All results agree with previous conclusions on the numerical efficiency of finite element preconditioning schemes.

  3. A subspace preconditioning algorithm for eigenvector/eigenvalue computation

    Energy Technology Data Exchange (ETDEWEB)

    Bramble, J.H.; Knyazev, A.V.; Pasciak, J.E.

    1996-12-31

    We consider the problem of computing a modest number of the smallest eigenvalues along with orthogonal bases for the corresponding eigen-spaces of a symmetric positive definite matrix. In our applications, the dimension of a matrix is large and the cost of its inverting is prohibitive. In this paper, we shall develop an effective parallelizable technique for computing these eigenvalues and eigenvectors utilizing subspace iteration and preconditioning. Estimates will be provided which show that the preconditioned method converges linearly and uniformly in the matrix dimension when used with a uniform preconditioner under the assumption that the approximating subspace is close enough to the span of desired eigenvectors.

  4. Effects of ketamine and its isomers on ischemic preconditioning in the isolated rat heart

    NARCIS (Netherlands)

    Molojavyi, A.; Preckel, B.; Comfère, T.; Müllenheim, J.; Thämer, V.; Schlack, W.

    2001-01-01

    BACKGROUND: Ischemic preconditioning protects the heart against subsequent ischemia. Opening of the adenosine triphosphate-sensitive potassium (KATP) channel is a key mechanism of preconditioning. Ketamine blocks KATP channels of isolated cardiomyocytes. The authors investigated the effects of

  5. Time-domain full waveform inversion using the gradient preconditioning based on transmitted waves energy

    KAUST Repository

    Zhang, Xiao-bo; Tan, Jun; Song, Peng; Li, Jin-shan; Xia, Dong-ming; Liu, Zhao-lun

    2017-01-01

    The gradient preconditioning approach based on seismic wave energy can effectively avoid the huge storage consumption in the gradient preconditioning algorithms based on Hessian matrices in time-domain full waveform inversion (FWI), but the accuracy

  6. The fruit of Acanthopanax senticosus (Rupr. et Maxim.) Harms improves insulin resistance and hepatic lipid accumulation by modulation of liver adenosine monophosphate-activated protein kinase activity and lipogenic gene expression in high-fat diet-fed obese mice.

    Science.gov (United States)

    Saito, Tetsuo; Nishida, Miyako; Saito, Masafumi; Tanabe, Akari; Eitsuka, Takahiro; Yuan, Shi-Hua; Ikekawa, Nobuo; Nishida, Hiroshi

    2016-10-01

    Obesity-associated insulin resistance is a major risk factor for most metabolic diseases, including dyslipidemia and type 2 diabetes. Acanthopanax senticosus (Rupr. et Maxim.) Harms (Goka) root has been used in traditional Chinese medicine for treatment of diabetes and other conditions; however, little is known about the effects of Goka fruit (GF). Goka fruit is rich in anthocyanin, which has beneficial effects on obesity and insulin resistance via activation of adenosine monophosphate-activated protein kinase (AMPK). We hypothesized that GF can improve obesity-associated insulin resistance. The aim of the present study was to investigate whether GF improves insulin resistance in high-fat diet (HFD)-induced obese mice. High-fat diet mice treated with GF (500 and 1000 mg/kg) for 12 weeks showed an improved glucose tolerance and insulin sensitivity, as well as reduced plasma insulin and liver lipid accumulation. Moreover, GF administration to HFD mice resulted in down-regulation of fatty acid synthase expression and up-regulation of cholesterol 7-alpha-hydroxylase expression in the liver. Notably, AMPK phosphorylation in the liver increased after GF administration. In summary, GF supplementation improved obesity-associated insulin resistance and hepatic lipid accumulation through modulation of AMPK activity and lipid metabolism-associated gene expression. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Maximal Bell's inequality violation for non-maximal entanglement

    International Nuclear Information System (INIS)

    Kobayashi, M.; Khanna, F.; Mann, A.; Revzen, M.; Santana, A.

    2004-01-01

    Bell's inequality violation (BIQV) for correlations of polarization is studied for a product state of two two-mode squeezed vacuum (TMSV) states. The violation allowed is shown to attain its maximal limit for all values of the squeezing parameter, ζ. We show via an explicit example that a state whose entanglement is not maximal allow maximal BIQV. The Wigner function of the state is non-negative and the average value of either polarization is nil

  8. Maximizing your Process Improvement ROI through Harmonization

    Science.gov (United States)

    2008-03-01

    ISO 12207 ) provide comprehensive guidance on what system and software engineering processes are needed. The frameworks of Six Sigma provide specific...reductions. Their veloci-Q Enterprise integrated system, includes ISO 9001, CMM, P-CMM, TL9000, British Standard 7799, and Six Sigma. They estimate a 30...at their discretion. And, they chose to blend process maturity models and ISO standards to support their objective regarding the establishment of

  9. 40 CFR 86.132-00 - Vehicle preconditioning.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Vehicle preconditioning. 86.132-00... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977 and Later Model Year New Light-Duty Vehicles and New Light-Duty Trucks and New Otto-Cycle Complete...

  10. 40 CFR 86.232-94 - Vehicle preconditioning.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Vehicle preconditioning. 86.232-94... (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium...

  11. Preconditioned stochastic gradient descent optimisation for monomodal image registration

    NARCIS (Netherlands)

    Klein, S.; Staring, M.; Andersson, J.P.; Pluim, J.P.W.; Fichtinger, G.; Martel, A.; Peters, T.

    2011-01-01

    We present a stochastic optimisation method for intensity-based monomodal image registration. The method is based on a Robbins-Monro stochastic gradient descent method with adaptive step size estimation, and adds a preconditioning matrix. The derivation of the pre-conditioner is based on the

  12. Manipulation in political stock markets: Preconditions and evidence

    OpenAIRE

    Hansen, Jan; Schmidt, Carsten; Strobel, Martin

    2001-01-01

    Political stock markets (PSM) are sometimes seen as substitutes for opinion polls. On the bases of a behavioral model, specific preconditions were drawn out under which manipulation in PSM can weaken this argument. Evidence for manipulation is reported from the data of two separate PSM during the Berlin 99 state elections.

  13. Preconditioned Iterative Methods for Solving Weighted Linear Least Squares Problems

    Czech Academy of Sciences Publication Activity Database

    Bru, R.; Marín, J.; Mas, J.; Tůma, Miroslav

    2014-01-01

    Roč. 36, č. 4 (2014), A2002-A2022 ISSN 1064-8275 Institutional support: RVO:67985807 Keywords : preconditioned iterative methods * incomplete decompositions * approximate inverses * linear least squares Subject RIV: BA - General Mathematics Impact factor: 1.854, year: 2014

  14. Preconditions of origin, essence and assignment of strategic managerial accounting

    OpenAIRE

    Boiko, I.

    2010-01-01

    The article is devoted to the research of preconditions and necessity of creation strategic managerial accounting in the accounting system of enterprise. There are investigated economic essence and assignment of strategic managerial accounting and substantiated its importance for making strategic decisions on an enterprise.

  15. New preconditioned conjugate gradient algorithms for nonlinear unconstrained optimization problems

    International Nuclear Information System (INIS)

    Al-Bayati, A.; Al-Asadi, N.

    1997-01-01

    This paper presents two new predilection conjugate gradient algorithms for nonlinear unconstrained optimization problems and examines their computational performance. Computational experience shows that the new proposed algorithms generally imp lone the efficiency of Nazareth's [13] preconditioned conjugate gradient algorithm. (authors). 16 refs., 1 tab

  16. Deflation in preconditioned conjugate gradient methods for Finite Element Problems

    NARCIS (Netherlands)

    Vermolen, F.J.; Vuik, C.; Segal, A.

    2002-01-01

    We investigate the influence of the value of deflation vectors at interfaces on the rate of convergence of preconditioned conjugate gradient methods applied to a Finite Element discretization for an elliptic equation. Our set-up is a Poisson problem in two dimensions with continuous or discontinuous

  17. Accurate reanalysis of structures by a preconditioned conjugate gradient method

    Czech Academy of Sciences Publication Activity Database

    Kirsch, U.; Kočvara, Michal; Zowe, J.

    2002-01-01

    Roč. 55, č. 2 (2002), s. 233-251 ISSN 0029-5981 R&D Projects: GA AV ČR IAA1075005 Grant - others:BMBF(DE) 03ZOM3ER Institutional research plan: CEZ:AV0Z1075907 Keywords : preconditioned conjugate gradient s * structural reanalysis Subject RIV: BA - General Mathematics Impact factor: 1.468, year: 2002

  18. Augmentation of aerobic respiration and mitochondrial biogenesis in skeletal muscle by hypoxia preconditioning with cobalt chloride

    International Nuclear Information System (INIS)

    Saxena, Saurabh; Shukla, Dhananjay; Bansal, Anju

    2012-01-01

    High altitude/hypoxia training is known to improve physical performance in athletes. Hypoxia induces hypoxia inducible factor-1 (HIF-1) and its downstream genes that facilitate hypoxia adaptation in muscle to increase physical performance. Cobalt chloride (CoCl 2 ), a hypoxia mimetic, stabilizes HIF-1, which otherwise is degraded in normoxic conditions. We studied the effects of hypoxia preconditioning by CoCl 2 supplementation on physical performance, glucose metabolism, and mitochondrial biogenesis using rodent model. The results showed significant increase in physical performance in cobalt supplemented rats without (two times) or with training (3.3 times) as compared to control animals. CoCl 2 supplementation in rats augmented the biological activities of enzymes of TCA cycle, glycolysis and cytochrome c oxidase (COX); and increased the expression of glucose transporter-1 (Glut-1) in muscle showing increased glucose metabolism by aerobic respiration. There was also an increase in mitochondrial biogenesis in skeletal muscle observed by increased mRNA expressions of mitochondrial biogenesis markers which was further confirmed by electron microscopy. Moreover, nitric oxide production increased in skeletal muscle in cobalt supplemented rats, which seems to be the major reason for peroxisome proliferator activated receptor-gamma coactivator-1α (PGC-1α) induction and mitochondrial biogenesis. Thus, in conclusion, we state that hypoxia preconditioning by CoCl 2 supplementation in rats increases mitochondrial biogenesis, glucose uptake and metabolism by aerobic respiration in skeletal muscle, which leads to increased physical performance. The significance of this study lies in understanding the molecular mechanism of hypoxia adaptation and improvement of work performance in normal as well as extreme conditions like hypoxia via hypoxia preconditioning. -- Highlights: ► We supplemented rats with CoCl 2 for 15 days along with training. ► CoCl 2 supplementation

  19. Electroacupuncture preconditioning reduces cerebral ischemic injury via BDNF and SDF-1α in mice

    Directory of Open Access Journals (Sweden)

    Kim Ji Hyun

    2013-01-01

    Full Text Available Abstract Background This study was designed to determine if electroacupuncture (EA preconditioning improves tissue outcome and functional outcome following experimentally induced cerebral ischemia in mice. In addition, we investigated whether the expression of brain-derived neurotrophic factor (BDNF and stromal cell derived factor-1α (SDF-1α and infarct volume were related with improvement in neurological and motor function by interventions in this study. Methods After treatment with EA at the acupoints ‘Baihui (GV20’ and ‘Dazhui (GV14’ for 20 min, BDNF was assessed in the cortical tissues based on Western blot and the SDF-1α and vascular endothelial growth factor (VEGF levels in the plasma determined by ELISA. To assess the protective effects of EA against ischemic injury, the mice received once a day 20 min EA preconditioning for three days prior to the ischemic event. Focal cerebral ischemia was then induced by photothrombotic cortical ischemia. Infarct volumes, neurobehavioral deficit and motor deficit were evaluated 24 h after focal cerebral ischemia. Results The expression of BDNF protein increased significantly from 6 h, reaching a plateau at 12 h after the end of EA treatment in the cerebral cortex. Furthermore, SDF-1α, not VEGF, increased singnificantly from 12 h to 48 h after EA stimulation in the plasma. Moreover, EA preconditioning reduced the infarct volume by 43.5% when compared to control mice at 24 h after photothrombotic cortical ischemia. Consistent with a smaller infarct size, EA preconditioning showed prominent improvement of neurological function and motor function such as vestibule-motor function, sensori-motor function and asymmetric forelimb use. The expression of BDNF colocalized within neurons and SDF-1α colocalized within the cerebral vascular endothelium was observed throughout the ischemic cortex by EA. Conclusions Pretreatment with EA increased the production of BDNF and SDF-1α, which elicited

  20. Maximally Symmetric Composite Higgs Models.

    Science.gov (United States)

    Csáki, Csaba; Ma, Teng; Shu, Jing

    2017-09-29

    Maximal symmetry is a novel tool for composite pseudo Goldstone boson Higgs models: it is a remnant of an enhanced global symmetry of the composite fermion sector involving a twisting with the Higgs field. Maximal symmetry has far-reaching consequences: it ensures that the Higgs potential is finite and fully calculable, and also minimizes the tuning. We present a detailed analysis of the maximally symmetric SO(5)/SO(4) model and comment on its observational consequences.

  1. Pharmacological preconditioning with GYKI 52466: a prophylactic approach to neuroprotection

    Directory of Open Access Journals (Sweden)

    Chelsea S Goulton

    2010-08-01

    Full Text Available Some toxins and drugs can trigger lasting neuroprotective mechanisms that enable neurons to resist a subsequent severe insult. This ‘pharmacological preconditioning’ has far-reaching implications for conditions in which blood flow to the brain is interrupted. We have previously shown that in vitro preconditioning with the AMPA receptor antagonist GYKI 52466 induces tolerance to kainic acid (KA toxicity in hippocampus. This effect persists well after washout of the drug and may be mediated via inverse agonism of G protein linked receptors. Given the amplifying nature of metabotropic modulation, we hypothesised that GYKI 52466 may be effective in reducing seizure severity at doses well below those normally associated with adverse side effects. Here we report that pharmacological preconditioning with low-dose GYKI imparts a significant protection against KA-induced seizures in vivo. GYKI (3 mg/kg, s.c., 90 to 180 min. prior to high-dose KA, markedly reduced seizure scores, virtually abolished all level 3 and level 4 seizures, and completely suppressed KA-induced hippocampal cFOS expression. In addition, preconditioned animals exhibited significant reductions in high frequency/high amplitude spiking and ECoG power in the delta, theta, alpha and beta bands during KA. Adverse behaviours often associated with higher doses of GYKI were not evident during preconditioning. The fact that GYKI is effective at doses well-below, and at pre-administration intervals well-beyond previous studies, suggests that a classical blockade of ionotropic AMPA receptors does not underlie anticonvulsant effects. Low-dose GYKI preconditioning may represent a novel, prophylactic strategy for neuroprotection in a field almost completely devoid of effective pharmaceuticals.

  2. Principles of maximally classical and maximally realistic quantum ...

    Indian Academy of Sciences (India)

    Principles of maximally classical and maximally realistic quantum mechanics. S M ROY. Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India. Abstract. Recently Auberson, Mahoux, Roy and Singh have proved a long standing conjecture of Roy and Singh: In 2N-dimensional phase space, ...

  3. Effect of ischemic preconditioning on land-based sprinting in team-sport athletes.

    Science.gov (United States)

    Gibson, Neil; White, James; Neish, Mhari; Murray, Andrew

    2013-11-01

    The study aimed to assess whether exposure to ischemic preconditioning (IPC) in a trained population would affect land-based maximal sprinting performance over 30 m. Twenty-five well-trained participants regularly involved in invasion-type team-sport events were recruited to take part in a randomized crossover study design. Participants underwent both an IPC and a placebo treatment involving 3 periods of 5-min occlusion applied unilaterally (3 × 5-min occlusion to each leg) at either 220 mmHg or 50 mmHg, respectively. Each period of occlusion was followed by 5 min of reperfusion. After treatment, 3 maximal sprints over a distance of 30 m were undertaken from a standing start interspersed with 1-min recovery. Split times were recorded at 10, 20, and 30 m. No significant effects of the IPC treatment were observed on sprint speed (P split timings; however, a small and negative effect was observed in female participants. Calculated effect sizes of the treatment were found to be trivial (swimming, further research is required to elucidate whether this is the case over distances associated with land-based events in track and field or in events reliant on repeated-sprint ability.

  4. Mohawk Maximizes Learning

    Science.gov (United States)

    Weinstein, Margery

    2012-01-01

    For flooring manufacturer Mohawk Industries, it is not enough to teach employees how to be great. The long-time Training Top 125 contender focused last year on helping employees to blaze their own learning paths while meeting organization imperatives. That meant improving the technology that supports employee performance, as well as creating new…

  5. An information maximization model of eye movements

    Science.gov (United States)

    Renninger, Laura Walker; Coughlan, James; Verghese, Preeti; Malik, Jitendra

    2005-01-01

    We propose a sequential information maximization model as a general strategy for programming eye movements. The model reconstructs high-resolution visual information from a sequence of fixations, taking into account the fall-off in resolution from the fovea to the periphery. From this framework we get a simple rule for predicting fixation sequences: after each fixation, fixate next at the location that minimizes uncertainty (maximizes information) about the stimulus. By comparing our model performance to human eye movement data and to predictions from a saliency and random model, we demonstrate that our model is best at predicting fixation locations. Modeling additional biological constraints will improve the prediction of fixation sequences. Our results suggest that information maximization is a useful principle for programming eye movements.

  6. Retinal metabolic events in preconditioning light stress as revealed by wide-spectrum targeted metabolomics.

    Science.gov (United States)

    de la Barca, Juan Manuel Chao; Huang, Nuan-Ting; Jiao, Haihan; Tessier, Lydie; Gadras, Cédric; Simard, Gilles; Natoli, Riccardo; Tcherkez, Guillaume; Reynier, Pascal; Valter, Krisztina

    2017-01-01

    Light is the primary stimulus for vision, but may also cause damage to the retina. Pre-exposing the retina to sub-lethal amount of light (or preconditioning) improves chances for retinal cells to survive acute damaging light stress. This study aims at exploring the changes in retinal metabolome after mild light stress and identifying mechanisms that may be involved in preconditioning. Retinas from 12 rats exposed to mild light stress (1000 lux × for 12 h) and 12 controls were collected one and seven days after light stress (LS). One retina was used for targeted metabolomics analysis using the Biocrates p180 kit while the fellow retina was used for histological and immunohistochemistry analysis. Immunohistochemistry confirmed that in this experiment, a mild LS with retinal immune response and minimal photoreceptor loss occurred. Compared to controls, LS induced an increased concentration in phosphatidylcholines. The concentration in some amino acids and biogenic amines, particularly those related to the nitric oxide pathway (like asymmetric dimethylarginine (ADMA), arginine and citrulline) also increased 1 day after LS. 7 days after LS, the concentration in two sphingomyelins and phenylethylamine was found to be higher. We further found that in controls, retina metabolome was different between males and females: male retinas had an increased concentration in tyrosine, acetyl-ornithine, phosphatidylcholines and (acyl)-carnitines. Besides retinal sexual metabolic dimorphism, this study shows that preconditioning is mostly associated with re-organisation of lipid metabolism and changes in amino acid composition, likely reflecting the involvement of arginine-dependent NO signalling.

  7. RESVERATROL PRECONDITIONING INDUCES A NOVEL EXTENDED WINDOW OF ISCHEMIC TOLERANCE IN THE MOUSE BRAIN

    Science.gov (United States)

    Koronowski, Kevin B.; Dave, Kunjan R.; Saul, Isabel; Camarena, Vladimir; Thompson, John W.; Neumann, Jake T.; Young, Juan I.; Perez-Pinzon, Miguel A.

    2015-01-01

    Background and Purpose Prophylactic treatments that afford neuroprotection against stroke may emerge from the field of preconditioning. Resveratrol mimics ischemic preconditioning, reducing ischemic brain injury when administered two days prior to global ischemia in rats. This protection is linked to Sirt1 and enhanced mitochondrial function possibly through its repression of UCP2. BDNF is another neuroprotective protein associated with Sirt1. In this study we sought to identify the conditions of resveratrol preconditioning (RPC) that most robustly induce neuroprotection against focal ischemia in mice. Methods We tested four different RPC paradigms against a middle cerebral artery occlusion (MCAo) model of stroke. Infarct volume and neurological score were calculated 24 hours following MCAo. Sirt1-chromatin binding was evaluated by ChIP-qPCR. Percoll gradients were used to isolate synaptic fractions and changes in protein expression were determined via Western blot analysis. BDNF concentration was measured using a BDNF-specific ELISA assay. Results While repetitive RPC induced neuroprotection from MCAo, strikingly one application of RPC 14 days prior to MCAo showed the most robust protection, reducing infarct volume by 33% and improving neurological score by 28%. Fourteen days following RPC, Sirt1 protein was increased 1.5 fold and differentially bound to the UCP2 and BDNF promoter regions. Accordingly, synaptic UCP2 protein decreased by 23% and cortical BDNF concentration increased 26%. Conclusions RPC induces a novel extended window of ischemic tolerance in the brain that lasts for at least 14 days. Our data suggest that this tolerance may be mediated by Sirt1, through upregulation of BDNF and downregulation of UCP2. PMID:26159789

  8. Application of preconditioned conjugate gradient-like methods to reactor kinetics

    International Nuclear Information System (INIS)

    Yang, D.Y.; Chen, G.S.; Chou, H.P.

    1993-01-01

    Several conjugate gradient-like (CG-like) methods are applied to solve the nonsymmetric linear systems of equations derived from the time-dependent two-dimensional two-energy-group neutron diffusion equations by a finite difference approximation. The methods are: the generalized conjugate residual method; the generalized conjugate gradient least-square method; the generalized minimal residual method (GMRES); the conjugate gradient square method; and a variant of bi-conjugate gradient method (Bi-CGSTAB). In order to accelerate these methods, six preconditioning techniques are investigated. Two are based on pointwise incomplete factorization: the incomplete LU (ILU) and the modified incomplete LU (MILU) decompositions; two, based on the block tridiagonal structure of the coefficient matrix, are blockwise and modified blockwise incomplete factorizations, BILU and MBILU; two are the alternating-direction implicit and symmetric successive overrelaxation (SSOR) preconditioners, derived from the basic iterative schemes. Comparisons are made by using CG-like methods combined with different preconditioners to solve a sequence of time-step reactor transient problems. Numerical tests indicate that preconditioned BI-CGSTAB with the preconditioner MBILU requires less CPU time and fewer iterations than other methods. The preconditioned CG-like methods are less sensitive to the time-step size used than the Chebyshev semi-iteration method and line SOR method. The indication is that the CGS, Bi-CGSTAB and GMRES methods are, on average, better than the other methods in reactor kinetics computation and that a good preconditioner is more important than the choice of CG-like methods. The MILU decomposition based on the conventional row-sum criterion has difficulty yielding a convergent solution and an improved version is introduced. (author)

  9. Maximizing petrochemicals from refineries

    Energy Technology Data Exchange (ETDEWEB)

    Glover, B.; Foley, T.; Frey, S. [UOP, Des Plaines, IL (United States)

    2007-07-01

    New fuel quality requirements and high growth rates for petrochemicals are providing both challenges and opportunities for refineries. A key challenge in refineries today is to improve of the value of the products from the FCC unit. In particular, light FCC naphtha and LCO are prime candidates for improved utilization. Processing options have been developed focusing on new opportunities for these traditional fuel components. The Total Petrochemicals/UOP Olefin Cracking Process cracks C4-C8 olefins to produce propylene and ethylene. This process can be integrated into FCC units running at all severity levels to produce valuable light olefins while reducing the olefin content of the light FCC naphtha. Integration of the Olefin Cracking Process with an FCC unit can be accomplished to allow a range of operating modes which can accommodate changing demand for propylene, cracked naphtha and alkylate. Other processes developed by UOP allow for upgrading LCO into a range of products including petrochemical grade xylenes, benzene, high cetane diesel and low sulfur high octane gasoline. Various processing options are available which allow the products from LCO conversion to be adjusted based on the needs and opportunities of an individual refinery, as well as the external petrochemical demand cycles. This presentation will examine recent refining and petrochemical trends and highlight new process technologies that can be used to generate additional revenue from petrochemical production while addressing evolving clean fuel demands. (orig.)

  10. Maximizing the optical network capacity.

    Science.gov (United States)

    Bayvel, Polina; Maher, Robert; Xu, Tianhua; Liga, Gabriele; Shevchenko, Nikita A; Lavery, Domaniç; Alvarado, Alex; Killey, Robert I

    2016-03-06

    Most of the digital data transmitted are carried by optical fibres, forming the great part of the national and international communication infrastructure. The information-carrying capacity of these networks has increased vastly over the past decades through the introduction of wavelength division multiplexing, advanced modulation formats, digital signal processing and improved optical fibre and amplifier technology. These developments sparked the communication revolution and the growth of the Internet, and have created an illusion of infinite capacity being available. But as the volume of data continues to increase, is there a limit to the capacity of an optical fibre communication channel? The optical fibre channel is nonlinear, and the intensity-dependent Kerr nonlinearity limit has been suggested as a fundamental limit to optical fibre capacity. Current research is focused on whether this is the case, and on linear and nonlinear techniques, both optical and electronic, to understand, unlock and maximize the capacity of optical communications in the nonlinear regime. This paper describes some of them and discusses future prospects for success in the quest for capacity. © 2016 The Authors.

  11. Maximizing and customer loyalty: Are maximizers less loyal?

    Directory of Open Access Journals (Sweden)

    Linda Lai

    2011-06-01

    Full Text Available Despite their efforts to choose the best of all available solutions, maximizers seem to be more inclined than satisficers to regret their choices and to experience post-decisional dissonance. Maximizers may therefore be expected to change their decisions more frequently and hence exhibit lower customer loyalty to providers of products and services compared to satisficers. Findings from the study reported here (N = 1978 support this prediction. Maximizers reported significantly higher intentions to switch to another service provider (television provider than satisficers. Maximizers' intentions to switch appear to be intensified and mediated by higher proneness to regret, increased desire to discuss relevant choices with others, higher levels of perceived knowledge of alternatives, and higher ego involvement in the end product, compared to satisficers. Opportunities for future research are suggested.

  12. Implications of maximal Jarlskog invariant and maximal CP violation

    International Nuclear Information System (INIS)

    Rodriguez-Jauregui, E.; Universidad Nacional Autonoma de Mexico

    2001-04-01

    We argue here why CP violating phase Φ in the quark mixing matrix is maximal, that is, Φ=90 . In the Standard Model CP violation is related to the Jarlskog invariant J, which can be obtained from non commuting Hermitian mass matrices. In this article we derive the conditions to have Hermitian mass matrices which give maximal Jarlskog invariant J and maximal CP violating phase Φ. We find that all squared moduli of the quark mixing elements have a singular point when the CP violation phase Φ takes the value Φ=90 . This special feature of the Jarlskog invariant J and the quark mixing matrix is a clear and precise indication that CP violating Phase Φ is maximal in order to let nature treat democratically all of the quark mixing matrix moduli. (orig.)

  13. Phenomenology of maximal and near-maximal lepton mixing

    International Nuclear Information System (INIS)

    Gonzalez-Garcia, M. C.; Pena-Garay, Carlos; Nir, Yosef; Smirnov, Alexei Yu.

    2001-01-01

    The possible existence of maximal or near-maximal lepton mixing constitutes an intriguing challenge for fundamental theories of flavor. We study the phenomenological consequences of maximal and near-maximal mixing of the electron neutrino with other (x=tau and/or muon) neutrinos. We describe the deviations from maximal mixing in terms of a parameter ε(equivalent to)1-2sin 2 θ ex and quantify the present experimental status for |ε| e mixing comes from solar neutrino experiments. We find that the global analysis of solar neutrino data allows maximal mixing with confidence level better than 99% for 10 -8 eV 2 ∼ 2 ∼ -7 eV 2 . In the mass ranges Δm 2 ∼>1.5x10 -5 eV 2 and 4x10 -10 eV 2 ∼ 2 ∼ -7 eV 2 the full interval |ε| e mixing in atmospheric neutrinos, supernova neutrinos, and neutrinoless double beta decay

  14. HMC algorithm with multiple time scale integration and mass preconditioning

    Science.gov (United States)

    Urbach, C.; Jansen, K.; Shindler, A.; Wenger, U.

    2006-01-01

    We present a variant of the HMC algorithm with mass preconditioning (Hasenbusch acceleration) and multiple time scale integration. We have tested this variant for standard Wilson fermions at β=5.6 and at pion masses ranging from 380 to 680 MeV. We show that in this situation its performance is comparable to the recently proposed HMC variant with domain decomposition as preconditioner. We give an update of the "Berlin Wall" figure, comparing the performance of our variant of the HMC algorithm to other published performance data. Advantages of the HMC algorithm with mass preconditioning and multiple time scale integration are that it is straightforward to implement and can be used in combination with a wide variety of lattice Dirac operators.

  15. Fourier domain preconditioned conjugate gradient algorithm for atmospheric tomography.

    Science.gov (United States)

    Yang, Qiang; Vogel, Curtis R; Ellerbroek, Brent L

    2006-07-20

    By 'atmospheric tomography' we mean the estimation of a layered atmospheric turbulence profile from measurements of the pupil-plane phase (or phase gradients) corresponding to several different guide star directions. We introduce what we believe to be a new Fourier domain preconditioned conjugate gradient (FD-PCG) algorithm for atmospheric tomography, and we compare its performance against an existing multigrid preconditioned conjugate gradient (MG-PCG) approach. Numerical results indicate that on conventional serial computers, FD-PCG is as accurate and robust as MG-PCG, but it is from one to two orders of magnitude faster for atmospheric tomography on 30 m class telescopes. Simulations are carried out for both natural guide stars and for a combination of finite-altitude laser guide stars and natural guide stars to resolve tip-tilt uncertainty.

  16. PRECONDITIONS AND DETERMINING CAUSES OF THE SHADOW ECONOMY IN UKRAINE

    Directory of Open Access Journals (Sweden)

    Z. Varnalii

    2014-03-01

    Full Text Available The article analyzes the main processes that led to the high level of the economy shadowing. The historical aspects of the formation of the shadow economy in Ukraine are highlighted. The socio-economic aspects of the shadow economy of Ukraine causality are discussed. The theoretical contribution of foreign and domestic researchers on the preconditions of formation of the shadow economy in transition economies is studied. Theoretical perspective on the factors of the shadowing processes in the economy of Ukraine from the standpoint of modern scientific researches is analyzed. The paper also provides scientific vectors for further development of researches aimed at studying the causes and preconditions of the shadow economy.

  17. Maximal quantum Fisher information matrix

    International Nuclear Information System (INIS)

    Chen, Yu; Yuan, Haidong

    2017-01-01

    We study the existence of the maximal quantum Fisher information matrix in the multi-parameter quantum estimation, which bounds the ultimate precision limit. We show that when the maximal quantum Fisher information matrix exists, it can be directly obtained from the underlying dynamics. Examples are then provided to demonstrate the usefulness of the maximal quantum Fisher information matrix by deriving various trade-off relations in multi-parameter quantum estimation and obtaining the bounds for the scalings of the precision limit. (paper)

  18. Krylov Subspace Methods for Saddle Point Problems with Indefinite Preconditioning

    Czech Academy of Sciences Publication Activity Database

    Rozložník, Miroslav; Simoncini, V.

    2002-01-01

    Roč. 24, č. 2 (2002), s. 368-391 ISSN 0895-4798 R&D Projects: GA ČR GA101/00/1035; GA ČR GA201/00/0080 Institutional research plan: AV0Z1030915 Keywords : saddle point problems * preconditioning * indefinite linear systems * finite precision arithmetic * conjugate gradients Subject RIV: BA - General Mathematics Impact factor: 0.753, year: 2002

  19. Ischemic preconditioning enhances integrity of coronary endothelial tight junctions

    International Nuclear Information System (INIS)

    Li, Zhao; Jin, Zhu-Qiu

    2012-01-01

    Highlights: ► Cardiac tight junctions are present between coronary endothelial cells. ► Ischemic preconditioning preserves the structural and functional integrity of tight junctions. ► Myocardial edema is prevented in hearts subjected to ischemic preconditioning. ► Ischemic preconditioning enhances translocation of ZO-2 from cytosol to cytoskeleton. -- Abstract: Ischemic preconditioning (IPC) is one of the most effective procedures known to protect hearts against ischemia/reperfusion (IR) injury. Tight junction (TJ) barriers occur between coronary endothelial cells. TJs provide barrier function to maintain the homeostasis of the inner environment of tissues. However, the effect of IPC on the structure and function of cardiac TJs remains unknown. We tested the hypothesis that myocardial IR injury ruptures the structure of TJs and impairs endothelial permeability whereas IPC preserves the structural and functional integrity of TJs in the blood–heart barrier. Langendorff hearts from C57BL/6J mice were prepared and perfused with Krebs–Henseleit buffer. Cardiac function, creatine kinase release, and myocardial edema were measured. Cardiac TJ function was evaluated by measuring Evans blue-conjugated albumin (EBA) content in the extravascular compartment of hearts. Expression and translocation of zonula occludens (ZO)-2 in IR and IPC hearts were detected with Western blot. A subset of hearts was processed for the observation of ultra-structure of cardiac TJs with transmission electron microscopy. There were clear TJs between coronary endothelial cells of mouse hearts. IR caused the collapse of TJs whereas IPC sustained the structure of TJs. IR increased extravascular EBA content in the heart and myocardial edema but decreased the expression of ZO-2 in the cytoskeleton. IPC maintained the structure of TJs. Cardiac EBA content and edema were reduced in IPC hearts. IPC enhanced the translocation of ZO-2 from cytosol to cytoskeleton. In conclusion, TJs occur in

  20. An Adaptive Multilevel Factorized Sparse Approximate Inverse Preconditioning

    Czech Academy of Sciences Publication Activity Database

    Kopal, Jiří; Rozložník, Miroslav; Tůma, Miroslav

    2017-01-01

    Roč. 113, November (2017), s. 19-24 ISSN 0965-9978 R&D Projects: GA ČR GA13-06684S Grant - others:GA MŠk(CZ) LL1202 Institutional support: RVO:67985807 Keywords : approximate inverse * Gram–Schmidt orthogonalization * incomplete factorization * multilevel methods * preconditioned conjugate gradient method Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 3.000, year: 2016

  1. Efficient Preconditioning of Sequences of Nonsymmetric Linear Systems

    Czech Academy of Sciences Publication Activity Database

    Duintjer Tebbens, Jurjen; Tůma, Miroslav

    2007-01-01

    Roč. 29, č. 5 (2007), s. 1918-1941 ISSN 1064-8275 R&D Projects: GA AV ČR 1ET400300415; GA AV ČR KJB100300703 Institutional research plan: CEZ:AV0Z10300504 Keywords : preconditioned iterative methods * sparse matrices * sequences of linear algebraic systems * incomplete factorizations * factorization updates * Gauss–Jordan transformations * minimum spanning tree Subject RIV: BA - General Mathematics Impact factor: 1.784, year: 2007

  2. Unified analysis of preconditioning methods for saddle point matrices

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe

    2015-01-01

    Roč. 22, č. 2 (2015), s. 233-253 ISSN 1070-5325 R&D Projects: GA MŠk ED1.1.00/02.0070 Institutional support: RVO:68145535 Keywords : saddle point problems * preconditioning * spectral properties Subject RIV: BA - General Mathematics Impact factor: 1.431, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/nla.1947/pdf

  3. Remote ischaemic preconditioning and prevention of cerebral injury.

    Science.gov (United States)

    Rehni, Ashish K; Shri, Richa; Singh, Manjeet

    2007-03-01

    Bilateral carotid artery occlusion of 10 min followed by reperfusion for 24 hr was employed in present study to produce ischaemia and reperfusion induced cerebral injury in mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Short-term memory was evaluated using elevated plus maze. Inclined beam walking test was employed to assess motor incoordination. Bilateral carotid artery occlusion followed by reperfusion produced cerebral infarction and impaired short-term memory, motor co-ordination and lateral push response. A preceding episode of mesenteric artery occlusion for 15 min and reperfusion of 15 min (remote mesenteric ischaemic preconditioning) prevented markedly ischaemia-reperfusion-induced cerebral injury measured in terms of infarct size, loss of short-term memory, motor coordination and lateral push response. Glibenclamide (5 mg/kg, iv) a KATP channel blocker and caffeine (7 mg/kg, iv) an adenosine receptor blocker attenuated the neuroprotective effect of remote mesenteric ischaemic preconditioning. It may be concluded that neuroprotective effect of remote mesenteric ischaemic preconditioning may be due to activation of adenosine receptors and consequent activation of KATP channels in mice.

  4. Preconditioned conjugate gradient methods for the Navier-Stokes equations

    Science.gov (United States)

    Ajmani, Kumud; Ng, Wing-Fai; Liou, Meng-Sing

    1994-01-01

    A preconditioned Krylov subspace method (GMRES) is used to solve the linear systems of equations formed at each time-integration step of the unsteady, two-dimensional, compressible Navier-Stokes equations of fluid flow. The Navier-Stokes equations are cast in an implicit, upwind finite-volume, flux-split formulation. Several preconditioning techniques are investigated to enhance the efficiency and convergence rate of the implicit solver based on the GMRES algorithm. The superiority of the new solver is established by comparisons with a conventional implicit solver, namely line Gauss-Seidel relaxation (LGSR). Computational test results for low-speed (incompressible flow over a backward-facing step at Mach 0.1), transonic flow (trailing edge flow in a transonic turbine cascade), and hypersonic flow (shock-on-shock interactions on a cylindrical leading edge at Mach 6.0) are presented. For the Mach 0.1 case, overall speedup factors of up to 17 (in terms of time-steps) and 15 (in terms of CPU time on a CRAY-YMP/8) are found in favor of the preconditioned GMRES solver, when compared with the LGSR solver. The corresponding speedup factors for the transonic flow case are 17 and 23, respectively. The hypersonic flow case shows slightly lower speedup factors of 9 and 13, respectively. The study of preconditioners conducted in this research reveals that a new LUSGS-type preconditioner is much more efficient than a conventional incomplete LU-type preconditioner.

  5. Acidic preconditioning of endothelial colony-forming cells (ECFC) promote vasculogenesis under proinflammatory and high glucose conditions in vitro and in vivo.

    Science.gov (United States)

    Mena, Hebe Agustina; Zubiry, Paula Romina; Dizier, Blandine; Schattner, Mirta; Boisson-Vidal, Catherine; Negrotto, Soledad

    2018-05-02

    signs of inflammation in the animals receiving preconditioned ECFC. Acidic preconditioning improved ECFC survival and angiogenic activity in the presence of proinflammatory and damage signals present in the ischemic milieu, even under high glucose conditions, and increased their therapeutic potential for postischemia tissue regeneration in a murine model of type 2 diabetes. Collectively, our data suggest that acidic preconditioning of ECFC is a simple and inexpensive strategy to improve the effectiveness of cell transplantation in diabetes, where tissue repair is highly compromised.

  6. Preconditioned Krylov and Gauss-Seidel solutions of response matrix equations

    International Nuclear Information System (INIS)

    Lewis, E.E.; Smith, M.A.; Yang, W.S.; Wollaber, A.

    2011-01-01

    The use of preconditioned Krylov methods is examined as an alternative to the partitioned matrix acceleration applied to red-black Gauss Seidel (RBGS) iteration that is presently used in the variational nodal code, VARIANT. We employ the GMRES algorithm to treat non-symmetric response matrix equations. A pre conditioner is formulated for the within-group diffusion equation which is equivalent to partitioned matrix acceleration of RBGS iterations. We employ the pre conditioner, which closely parallels two-level p multigrid, to improve RBGS and GMRES algorithms. Of the accelerated algorithms, GMRES converges with less computational effort than RBGS and therefore is chosen for further development. The p multigrid pre conditioner requires response matrices with two or more degrees of freedom (DOF) per interface that are polynomials, which are both orthogonal and hierarchical. It is therefore not directly applicable to very fine mesh calculations that are both slow to converge and that are often modeled with response matrices with only one DOF per interface. Orthogonal matrix aggregation (OMA) is introduced to circumvent this difficulty by combining N×N fine mesh response matrices with one DOF per interface into a coarse mesh response matrix with N orthogonal DOF per interface. Numerical results show that OMA used alone or in combination with p multigrid preconditioning substantially accelerates GMRES solutions. (author)

  7. Preconditioned Krylov and Gauss-Seidel solutions of response matrix equations

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, E.E., E-mail: e-lewis@northwestern.edu [Department of Mechanical Engineering, Northwestern University, Evanston, IL (United States); Smith, M.A.; Yang, W.S.; Wollaber, A., E-mail: masmith@anl.gov, E-mail: wsyang@anl.gov, E-mail: wollaber@lanl.gov [Nuclear Engineering Division, Argonne National Laboratory, Argonne, IL (United States)

    2011-07-01

    The use of preconditioned Krylov methods is examined as an alternative to the partitioned matrix acceleration applied to red-black Gauss Seidel (RBGS) iteration that is presently used in the variational nodal code, VARIANT. We employ the GMRES algorithm to treat non-symmetric response matrix equations. A pre conditioner is formulated for the within-group diffusion equation which is equivalent to partitioned matrix acceleration of RBGS iterations. We employ the pre conditioner, which closely parallels two-level p multigrid, to improve RBGS and GMRES algorithms. Of the accelerated algorithms, GMRES converges with less computational effort than RBGS and therefore is chosen for further development. The p multigrid pre conditioner requires response matrices with two or more degrees of freedom (DOF) per interface that are polynomials, which are both orthogonal and hierarchical. It is therefore not directly applicable to very fine mesh calculations that are both slow to converge and that are often modeled with response matrices with only one DOF per interface. Orthogonal matrix aggregation (OMA) is introduced to circumvent this difficulty by combining N×N fine mesh response matrices with one DOF per interface into a coarse mesh response matrix with N orthogonal DOF per interface. Numerical results show that OMA used alone or in combination with p multigrid preconditioning substantially accelerates GMRES solutions. (author)

  8. The role and dynamics of β-catenin in precondition induced neuroprotection after traumatic brain injury.

    Directory of Open Access Journals (Sweden)

    Gali Umschweif

    Full Text Available Preconditioning via heat acclimation (34°C 30 d results in neuroprotection from traumatic brain injury due to constitutive as well as dynamic changes triggered by the trauma. Among these changes is Akt phosphorylation, which decreases apoptosis and induces HIF1α. In the present study we investigated the Akt downstream GSK3β/β-catenin pathway and focused on post injury alternations of β catenin and its impact on the cellular response in preconditioned heat acclimated mice. We found that the reduction in motor disability is accompanied with attenuation of depressive like behavior in heat acclimated mice that correlates with the GSK3β phosphorylation state. Concomitantly, a robust β catenin phosphorylation is not followed by its degradation, or by reduced nuclear accumulation. Enhanced tyrosine phosphorylation of β catenin in the injured area weakens the β catenin-N cadherin complex. Membrane β catenin is transiently reduced in heat acclimated mice and its recovery 7 days post TBI is accompanied by induction of the synaptic marker synaptophysin. We suggest a set of cellular events following traumatic brain injury in heat acclimated mice that causes β catenin to participate in cell-cell adhesion alternations rather than in Wnt signaling. These events may contribute to synaptogenesis and the improved motor and cognitive abilities seen heat acclimated mice after traumatic brain injury.

  9. Electroacupuncture preconditioning-induced neuroprotection may be mediated by glutamate transporter type 2.

    Science.gov (United States)

    Zhu, Xiaoling; Yin, Jinbo; Li, Liaoliao; Ma, Lei; Tan, Hongying; Deng, Jiao; Chen, Shaoyang; Zuo, Zhiyi

    2013-10-01

    Electroacupuncture has been shown to induce a preconditioning effect in the brain. The mechanisms for this protection are not fully elucidated. We hypothesize that this protection is mediated by excitatory amino acid transporters (EAATs) that have been shown to be neuroprotective. To test this hypothesis, two-month old male Sprague-Dawley rats and EAAT type 3 (EAAT3) knockout mice received or did not receive 30-min electroacupuncture once a day for five consecutive days. They were subjected to a 120-min middle cerebral arterial occlusion (MCAO) at 24h after the last electroacupuncture. Neurological outcome was assessed 2days after the MCAO. Brain tissues were harvested at 24h after the last electroacupuncture for Western blotting. Rats subjected to electroacupuncture at the Baihui acupoint had smaller brain infarct volumes and better neurological deficit scores than control rats. Electroacupuncture increased EAAT type 2 (EAAT2) in the cerebral cortex, tended to increase EAAT3 in the hippocampus, and had no effect on EAAT type 1 expression. Dihydrokainate, an EAAT2 inhibitor, worsened the neurological outcome of rats with electroacupuncture pretreatment. Electroacupuncture pretreatment at the Baihui acupoint increased EAAT2 in the cerebral cortex and improved the neurological outcome of EAAT3 knockout mice. Together, our results suggest that EAAT2 may mediate the electroacupuncture preconditioning-induced neuroprotection. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Maximize x(a - x)

    Science.gov (United States)

    Lange, L. H.

    1974-01-01

    Five different methods for determining the maximizing condition for x(a - x) are presented. Included is the ancient Greek version and a method attributed to Fermat. None of the proofs use calculus. (LS)

  11. Finding Maximal Quasiperiodicities in Strings

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Pedersen, Christian N. S.

    2000-01-01

    of length n in time O(n log n) and space O(n). Our algorithm uses the suffix tree as the fundamental data structure combined with efficient methods for merging and performing multiple searches in search trees. Besides finding all maximal quasiperiodic substrings, our algorithm also marks the nodes......Apostolico and Ehrenfeucht defined the notion of a maximal quasiperiodic substring and gave an algorithm that finds all maximal quasiperiodic substrings in a string of length n in time O(n log2 n). In this paper we give an algorithm that finds all maximal quasiperiodic substrings in a string...... in the suffix tree that have a superprimitive path-label....

  12. On the maximal diphoton width

    CERN Document Server

    Salvio, Alberto; Strumia, Alessandro; Urbano, Alfredo

    2016-01-01

    Motivated by the 750 GeV diphoton excess found at LHC, we compute the maximal width into $\\gamma\\gamma$ that a neutral scalar can acquire through a loop of charged fermions or scalars as function of the maximal scale at which the theory holds, taking into account vacuum (meta)stability bounds. We show how an extra gauge symmetry can qualitatively weaken such bounds, and explore collider probes and connections with Dark Matter.

  13. Winter sea ice export from the Laptev Sea preconditions the local summer sea ice cover and fast ice decay

    Directory of Open Access Journals (Sweden)

    P. Itkin

    2017-10-01

    Full Text Available Ice retreat in the eastern Eurasian Arctic is a consequence of atmospheric and oceanic processes and regional feedback mechanisms acting on the ice cover, both in winter and summer. A correct representation of these processes in numerical models is important, since it will improve predictions of sea ice anomalies along the Northeast Passage and beyond. In this study, we highlight the importance of winter ice dynamics for local summer sea ice anomalies in thickness, volume and extent. By means of airborne sea ice thickness surveys made over pack ice areas in the south-eastern Laptev Sea, we show that years of offshore-directed sea ice transport have a thinning effect on the late-winter sea ice cover. To confirm the preconditioning effect of enhanced offshore advection in late winter on the summer sea ice cover, we perform a sensitivity study using a numerical model. Results verify that the preconditioning effect plays a bigger role for the regional ice extent. Furthermore, they indicate an increase in volume export from the Laptev Sea as a consequence of enhanced offshore advection, which has far-reaching consequences for the entire Arctic sea ice mass balance. Moreover we show that ice dynamics in winter not only preconditions local summer ice extent, but also accelerate fast-ice decay.

  14. Hypoxia-inducible factor-1 alpha has a key role in hypoxic preconditioning.

    Science.gov (United States)

    Taie, Satoshi; Ono, Junichiro; Iwanaga, Yasuyuki; Tomita, Shuhei; Asaga, Takehiko; Chujo, Kosuke; Ueki, Masaaki

    2009-08-01

    Sublethal hypoxia induces tolerance to subsequent hypoxic insults in a process known as hypoxic preconditioning (HP). Hypoxia-inducible factor-1 alpha (HIF-1 alpha) is a key transcription protein involved in the mechanism of HP. In this study, we investigated the effects of HP on tissue oxygenation and expression of HIF-1 alpha gene targets in the brain using neural cell-specific HIF-1 alpha-deficient mice. The animals were exposed to 8% oxygen for 3 hours. Twenty-four hours later, the oxygen partial pressure (pO(2)) of brain tissue and gene expression were measured during hypoxia. HP improved the pO(2) of brain tissue during subsequent hypoxia with upregulated inducible nitric oxide synthase in wild-type mice, whereas HP had no detectable effect in the mutant mice. Our results indicate that the protective effects of HP may be partially mediated by improving tissue oxygenation via HIF-1 alpha and inducible nitric oxide synthase.

  15. Maximization

    Directory of Open Access Journals (Sweden)

    A. Garmroodi Asil

    2017-09-01

    To further reduce the sulfur dioxide emission of the entire refining process, two scenarios of acid gas or air preheats are investigated when either of them is used simultaneously with the third enrichment scheme. The maximum overall sulfur recovery efficiency and highest combustion chamber temperature is slightly higher for acid gas preheats but air preheat is more favorable because it is more benign. To the best of our knowledge, optimization of the entire GTU + enrichment section and SRU processes has not been addressed previously.

  16. Nuclear medicine methods in the field of studying the mechanisms of delayed phase of myocardial preconditioning

    International Nuclear Information System (INIS)

    Wang Shuxia

    2001-01-01

    Ischemic preconditioning is the intrinsic and most potently myocardial protection. Its mechanism is the foundation of rational therapeutic application. Nowadays there are some theories about delayed phase of preconditioning such as nitric oxide hypothesis, free radical mechanisms, protective protein synthesis and opening of ATP-sensitive potassium channels. By incorporation 3 H-leucine, using liquid scintillation counter, the authors know there was protective protein synthesis during preconditioning. SPECT could study the characteristics of preconditioned myocardium in vivo, and PET might further show the metabolism, energy consumption and its relationship to myocardium dysfunction

  17. Preconditioned iterative methods for space-time fractional advection-diffusion equations

    Science.gov (United States)

    Zhao, Zhi; Jin, Xiao-Qing; Lin, Matthew M.

    2016-08-01

    In this paper, we propose practical numerical methods for solving a class of initial-boundary value problems of space-time fractional advection-diffusion equations. First, we propose an implicit method based on two-sided Grünwald formulae and discuss its stability and consistency. Then, we develop the preconditioned generalized minimal residual (preconditioned GMRES) method and preconditioned conjugate gradient normal residual (preconditioned CGNR) method with easily constructed preconditioners. Importantly, because resulting systems are Toeplitz-like, fast Fourier transform can be applied to significantly reduce the computational cost. We perform numerical experiments to demonstrate the efficiency of our preconditioners, even in cases with variable coefficients.

  18. Maximizing Entropy over Markov Processes

    DEFF Research Database (Denmark)

    Biondi, Fabrizio; Legay, Axel; Nielsen, Bo Friis

    2013-01-01

    The channel capacity of a deterministic system with confidential data is an upper bound on the amount of bits of data an attacker can learn from the system. We encode all possible attacks to a system using a probabilistic specification, an Interval Markov Chain. Then the channel capacity...... as a reward function, a polynomial algorithm to verify the existence of an system maximizing entropy among those respecting a specification, a procedure for the maximization of reward functions over Interval Markov Chains and its application to synthesize an implementation maximizing entropy. We show how...... to use Interval Markov Chains to model abstractions of deterministic systems with confidential data, and use the above results to compute their channel capacity. These results are a foundation for ongoing work on computing channel capacity for abstractions of programs derived from code....

  19. Maximizing entropy over Markov processes

    DEFF Research Database (Denmark)

    Biondi, Fabrizio; Legay, Axel; Nielsen, Bo Friis

    2014-01-01

    The channel capacity of a deterministic system with confidential data is an upper bound on the amount of bits of data an attacker can learn from the system. We encode all possible attacks to a system using a probabilistic specification, an Interval Markov Chain. Then the channel capacity...... as a reward function, a polynomial algorithm to verify the existence of a system maximizing entropy among those respecting a specification, a procedure for the maximization of reward functions over Interval Markov Chains and its application to synthesize an implementation maximizing entropy. We show how...... to use Interval Markov Chains to model abstractions of deterministic systems with confidential data, and use the above results to compute their channel capacity. These results are a foundation for ongoing work on computing channel capacity for abstractions of programs derived from code. © 2014 Elsevier...

  20. Preconditioned Conjugate Gradient methods for low speed flow calculations

    Science.gov (United States)

    Ajmani, Kumud; Ng, Wing-Fai; Liou, Meng-Sing

    1993-01-01

    An investigation is conducted into the viability of using a generalized Conjugate Gradient-like method as an iterative solver to obtain steady-state solutions of very low-speed fluid flow problems. Low-speed flow at Mach 0.1 over a backward-facing step is chosen as a representative test problem. The unsteady form of the two dimensional, compressible Navier-Stokes equations are integrated in time using discrete time-steps. The Navier-Stokes equations are cast in an implicit, upwind finite-volume, flux split formulation. The new iterative solver is used to solve a linear system of equations at each step of the time-integration. Preconditioning techniques are used with the new solver to enhance the stability and the convergence rate of the solver and are found to be critical to the overall success of the solver. A study of various preconditioners reveals that a preconditioner based on the lower-upper (L-U)-successive symmetric over-relaxation iterative scheme is more efficient than a preconditioner based on incomplete L-U factorizations of the iteration matrix. The performance of the new preconditioned solver is compared with a conventional line Gauss-Seidel relaxation (LGSR) solver. Overall speed-up factors of 28 (in terms of global time-steps required to converge to a steady-state solution) and 20 (in terms of total CPU time on one processor of a CRAY-YMP) are found in favor of the new preconditioned solver, when compared with the LGSR solver.

  1. Augmentation of aerobic respiration and mitochondrial biogenesis in skeletal muscle by hypoxia preconditioning with cobalt chloride

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, Saurabh [Experimental Biology Division, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054 (India); Shukla, Dhananjay [Department of Biotechnology, Gitam University, Gandhi Nagar, Rushikonda, Visakhapatnam-530 045 Andhra Pradesh (India); Bansal, Anju, E-mail: anjubansaldipas@gmail.com [Experimental Biology Division, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054 (India)

    2012-11-01

    High altitude/hypoxia training is known to improve physical performance in athletes. Hypoxia induces hypoxia inducible factor-1 (HIF-1) and its downstream genes that facilitate hypoxia adaptation in muscle to increase physical performance. Cobalt chloride (CoCl{sub 2}), a hypoxia mimetic, stabilizes HIF-1, which otherwise is degraded in normoxic conditions. We studied the effects of hypoxia preconditioning by CoCl{sub 2} supplementation on physical performance, glucose metabolism, and mitochondrial biogenesis using rodent model. The results showed significant increase in physical performance in cobalt supplemented rats without (two times) or with training (3.3 times) as compared to control animals. CoCl{sub 2} supplementation in rats augmented the biological activities of enzymes of TCA cycle, glycolysis and cytochrome c oxidase (COX); and increased the expression of glucose transporter-1 (Glut-1) in muscle showing increased glucose metabolism by aerobic respiration. There was also an increase in mitochondrial biogenesis in skeletal muscle observed by increased mRNA expressions of mitochondrial biogenesis markers which was further confirmed by electron microscopy. Moreover, nitric oxide production increased in skeletal muscle in cobalt supplemented rats, which seems to be the major reason for peroxisome proliferator activated receptor-gamma coactivator-1α (PGC-1α) induction and mitochondrial biogenesis. Thus, in conclusion, we state that hypoxia preconditioning by CoCl{sub 2} supplementation in rats increases mitochondrial biogenesis, glucose uptake and metabolism by aerobic respiration in skeletal muscle, which leads to increased physical performance. The significance of this study lies in understanding the molecular mechanism of hypoxia adaptation and improvement of work performance in normal as well as extreme conditions like hypoxia via hypoxia preconditioning. -- Highlights: ► We supplemented rats with CoCl{sub 2} for 15 days along with training. ► Co

  2. Design Considerations for a Flexible Multigrid Preconditioning Library

    Directory of Open Access Journals (Sweden)

    Jérémie Gaidamour

    2012-01-01

    Full Text Available MueLu is a library within the Trilinos software project [An overview of Trilinos, Technical Report SAND2003-2927, Sandia National Laboratories, 2003] and provides a framework for parallel multigrid preconditioning methods for large sparse linear systems. While providing efficient implementations of modern multigrid methods based on smoothed aggregation and energy minimization concepts, MueLu is designed to be customized and extended. This article gives an overview of design considerations for the MueLu package: user interfaces, internal design, data management, usage of modern software constructs, leveraging Trilinos capabilities, linear algebra operations and advanced application.

  3. Preconditioning for Mixed Finite Element Formulations of Elliptic Problems

    KAUST Repository

    Wildey, Tim; Xue, Guangri

    2013-01-01

    In this paper, we discuss a preconditioning technique for mixed finite element discretizations of elliptic equations. The technique is based on a block-diagonal approximation of the mass matrix which maintains the sparsity and positive definiteness of the corresponding Schur complement. This preconditioner arises from the multipoint flux mixed finite element method and is robust with respect to mesh size and is better conditioned for full permeability tensors than a preconditioner based on a diagonal approximation of the mass matrix. © Springer-Verlag Berlin Heidelberg 2013.

  4. Ischemic preconditioning enhances integrity of coronary endothelial tight junctions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhao [Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007 (United States); Jin, Zhu-Qiu, E-mail: zhu-qiu.jin@sdstate.edu [Department of Pharmaceutical Sciences, College of Pharmacy, South Dakota State University, Brookings, SD 57007 (United States)

    2012-08-31

    Highlights: Black-Right-Pointing-Pointer Cardiac tight junctions are present between coronary endothelial cells. Black-Right-Pointing-Pointer Ischemic preconditioning preserves the structural and functional integrity of tight junctions. Black-Right-Pointing-Pointer Myocardial edema is prevented in hearts subjected to ischemic preconditioning. Black-Right-Pointing-Pointer Ischemic preconditioning enhances translocation of ZO-2 from cytosol to cytoskeleton. -- Abstract: Ischemic preconditioning (IPC) is one of the most effective procedures known to protect hearts against ischemia/reperfusion (IR) injury. Tight junction (TJ) barriers occur between coronary endothelial cells. TJs provide barrier function to maintain the homeostasis of the inner environment of tissues. However, the effect of IPC on the structure and function of cardiac TJs remains unknown. We tested the hypothesis that myocardial IR injury ruptures the structure of TJs and impairs endothelial permeability whereas IPC preserves the structural and functional integrity of TJs in the blood-heart barrier. Langendorff hearts from C57BL/6J mice were prepared and perfused with Krebs-Henseleit buffer. Cardiac function, creatine kinase release, and myocardial edema were measured. Cardiac TJ function was evaluated by measuring Evans blue-conjugated albumin (EBA) content in the extravascular compartment of hearts. Expression and translocation of zonula occludens (ZO)-2 in IR and IPC hearts were detected with Western blot. A subset of hearts was processed for the observation of ultra-structure of cardiac TJs with transmission electron microscopy. There were clear TJs between coronary endothelial cells of mouse hearts. IR caused the collapse of TJs whereas IPC sustained the structure of TJs. IR increased extravascular EBA content in the heart and myocardial edema but decreased the expression of ZO-2 in the cytoskeleton. IPC maintained the structure of TJs. Cardiac EBA content and edema were reduced in IPC hearts. IPC

  5. Parallel preconditioned conjugate gradient algorithm applied to neutron diffusion problem

    International Nuclear Information System (INIS)

    Majumdar, A.; Martin, W.R.

    1992-01-01

    Numerical solution of the neutron diffusion problem requires solving a linear system of equations such as Ax = b, where A is an n x n symmetric positive definite (SPD) matrix; x and b are vectors with n components. The preconditioned conjugate gradient (PCG) algorithm is an efficient iterative method for solving such a linear system of equations. In this paper, the authors describe the implementation of a parallel PCG algorithm on a shared memory machine (BBN TC2000) and on a distributed workstation (IBM RS6000) environment created by the parallel virtual machine parallelization software

  6. Incomplete block factorization preconditioning for indefinite elliptic problems

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Chun-Hua [Univ. of Calgary, Alberta (Canada)

    1996-12-31

    The application of the finite difference method to approximate the solution of an indefinite elliptic problem produces a linear system whose coefficient matrix is block tridiagonal and symmetric indefinite. Such a linear system can be solved efficiently by a conjugate residual method, particularly when combined with a good preconditioner. We show that specific incomplete block factorization exists for the indefinite matrix if the mesh size is reasonably small. And this factorization can serve as an efficient preconditioner. Some efforts are made to estimate the eigenvalues of the preconditioned matrix. Numerical results are also given.

  7. Chamaebatiaria millefolium (Torr.) Maxim.: fernbush

    Science.gov (United States)

    Nancy L. Shaw; Emerenciana G. Hurd

    2008-01-01

    Fernbush - Chamaebatiaria millefolium (Torr.) Maxim. - the only species in its genus, is endemic to the Great Basin, Colorado Plateau, and adjacent areas of the western United States. It is an upright, generally multistemmed, sweetly aromatic shrub 0.3 to 2 m tall. Bark of young branches is brown and becomes smooth and gray with age. Leaves are leathery, alternate,...

  8. Roles of thioredoxin in nitric oxide-dependent preconditioning-induced tolerance against MPTP neurotoxin

    International Nuclear Information System (INIS)

    Chiueh, C.C.; Andoh, Tsugunobu; Chock, P. Boon

    2005-01-01

    Hormesis, a stress tolerance, can be induced by ischemic preconditioning stress. In addition to preconditioning, it may be induced by other means, such as gas anesthetics. Preconditioning mechanisms, which may be mediated by reprogramming survival genes and proteins, are obscure. A known neurotoxicant, 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), causes less neurotoxicity in the mice that are preconditioned. Pharmacological evidences suggest that the signaling pathway of ·NO-cGMP-PKG (protein kinase G) may mediate preconditioning phenomenon. We developed a human SH-SY5Y cell model for investigating · NO-mediated signaling pathway, gene regulation, and protein expression following a sublethal preconditioning stress caused by a brief 2-h serum deprivation. Preconditioned human SH-SY5Y cells are more resistant against severe oxidative stress and apoptosis caused by lethal serum deprivation and 1-mehtyl-4-phenylpyridinium (MPP + ). Both sublethal and lethal oxidative stress caused by serum withdrawal increased neuronal nitric oxide synthase (nNOS/NOS1) expression and · NO levels to a similar extent. In addition to free radical scavengers, inhibition of nNOS, guanylyl cyclase, and PKG blocks hormesis induced by preconditioning. S-nitrosothiols and 6-Br-cGMP produce a cytoprotection mimicking the action of preconditioning tolerance. There are two distinct cGMP-mediated survival pathways: (i) the up-regulation of a redox protein thioredoxin (Trx) for elevating mitochondrial levels of antioxidant protein Mn superoxide dismutase (MnSOD) and antiapoptotic protein Bcl-2, and (ii) the activation of mitochondrial ATP-sensitive potassium channels [K(ATP)]. Preconditioning induction of Trx increased tolerance against MPP + , which was blocked by Trx mRNA antisense oligonucleotide and Trx reductase inhibitor. It is concluded that Trx plays a pivotal role in · NO-dependent preconditioning hormesis against MPTP/MPP +

  9. Practical Preconditions for the Development of the Interdisciplinary Collaboration Competence in Healthcare

    Directory of Open Access Journals (Sweden)

    Raimonda Brunevičiūtė

    2011-12-01

    Full Text Available This article presents the results of the fourth stage of the longitudinal research performed at Kaunas University of Medicine (since 2010 – Lithuanian University of Health Sciences and Vytautas Magnus University. The main goal of the research was to investigate educational possibilities and preconditions for the development of the education of professional intercultural communication for students in the education programs of medicine and social work. Previous stages of the study revealed the peculiarities of intercultural/interdisciplinary teamwork, and educational premises for professional education of the team members. The fourth stage of the study is focused on the analysis of the practical activity of the interdisciplinary (intercultural team, striving to improve health specialists’ and social workers’ interdisciplinary collaboration competence.

  10. Application of the DSA preconditioned GMRES formalism to the method of characteristics - First results

    International Nuclear Information System (INIS)

    Le Tellier, R.; Hebert, A.

    2004-01-01

    The method of characteristics is well known for its slow convergence; consequently, as it is often done for SN methods, the Generalized Minimal Residual approach (GMRES) has been investigated for its practical implementation and its high reliability. GMRES is one of the most effective Krylov iterative methods to solve large linear systems. Moreover, the system has been 'left preconditioned' with the Algebraic Collapsing Acceleration (ACA) a variant of the Diffusion Synthetic Acceleration (DSA) based on I. Suslov's former works. This paper presents the first numerical results of these methods in 2D geometries with material discontinuities. Indeed, previous investigations have shown a degraded effectiveness of Diffusion Synthetic Accelerations with this kind of geometries. Results are presented for 9 x 9 Cartesian assemblies in terms of the speed of convergence of the inner iterations (fixed source) of the method of characteristics. It shows a significant improvement on the convergence rate. (authors)

  11. Fully 3D PET image reconstruction using a fourier preconditioned conjugate-gradient algorithm

    International Nuclear Information System (INIS)

    Fessler, J.A.; Ficaro, E.P.

    1996-01-01

    Since the data sizes in fully 3D PET imaging are very large, iterative image reconstruction algorithms must converge in very few iterations to be useful. One can improve the convergence rate of the conjugate-gradient (CG) algorithm by incorporating preconditioning operators that approximate the inverse of the Hessian of the objective function. If the 3D cylindrical PET geometry were not truncated at the ends, then the Hessian of the penalized least-squares objective function would be approximately shift-invariant, i.e. G'G would be nearly block-circulant, where G is the system matrix. We propose a Fourier preconditioner based on this shift-invariant approximation to the Hessian. Results show that this preconditioner significantly accelerates the convergence of the CG algorithm with only a small increase in computation

  12. Amelioration of rCBF and PbtO2 following TBI at high altitude by hyperbaric oxygen pre-conditioning.

    Science.gov (United States)

    Hu, Shengli; Li, Fei; Luo, Haishui; Xia, Yongzhi; Zhang, Jiuquan; Hu, Rong; Cui, Gaoyu; Meng, Hui; Feng, Hua

    2010-03-01

    Hypobaric hypoxia at high altitude can lead to brain damage and pre-conditioning with hyperbaric oxygen (HBO) can reduce ischemic/hypoxic brain injury. This study investigates the effects of high altitude on traumatic brain injury (TBI) and examines the neuroprotection provided by HBO preconditioning against TBI. Rats were randomly divided into four groups: HBO pre-conditioning group (HBOP, n=10), high altitude group (HA, n=10), plain control group (PC, n=10) and plain sham operation group (sham, n=10). All groups were subjected to head trauma by weight drop device except for the sham group. Rats from each group were examined for neurological function, regional cerebral blood flow (rCBF) and brain tissue oxygen pressure (PbtO(2)) and were killed for analysis by transmission electron microscope. The score of neurological deficits in the HA group was highest, followed by the HBOP group and the PC group, respectively. Both rCBF and PbtO(2) were the lowest in the HA group. Brain morphology and structure seen via the transmission electron microscope was diminished in the HA group, while fewer pathological injuries occurred in the HBOP and PC groups. High altitude aggravates TBI significantly and HBO pre-conditioning can attenuate TBI in rats at high altitude by improvement of rCBF and PbtO(2). Pre-treatment with HBO might be beneficial for people traveling to high altitude locations.

  13. Preconditioning 2D Integer Data for Fast Convex Hull Computations.

    Science.gov (United States)

    Cadenas, José Oswaldo; Megson, Graham M; Luengo Hendriks, Cris L

    2016-01-01

    In order to accelerate computing the convex hull on a set of n points, a heuristic procedure is often applied to reduce the number of points to a set of s points, s ≤ n, which also contains the same hull. We present an algorithm to precondition 2D data with integer coordinates bounded by a box of size p × q before building a 2D convex hull, with three distinct advantages. First, we prove that under the condition min(p, q) ≤ n the algorithm executes in time within O(n); second, no explicit sorting of data is required; and third, the reduced set of s points forms a simple polygonal chain and thus can be directly pipelined into an O(n) time convex hull algorithm. This paper empirically evaluates and quantifies the speed up gained by preconditioning a set of points by a method based on the proposed algorithm before using common convex hull algorithms to build the final hull. A speedup factor of at least four is consistently found from experiments on various datasets when the condition min(p, q) ≤ n holds; the smaller the ratio min(p, q)/n is in the dataset, the greater the speedup factor achieved.

  14. Bilirubin nanoparticle preconditioning protects against hepatic ischemia-reperfusion injury.

    Science.gov (United States)

    Kim, Jin Yong; Lee, Dong Yun; Kang, Sukmo; Miao, Wenjun; Kim, Hyungjun; Lee, Yonghyun; Jon, Sangyong

    2017-07-01

    Hepatic ischemia-reperfusion injury (IRI) remains a major concern in liver transplantation and resection, despite continuing efforts to prevent it. Accumulating evidence suggests that bilirubin possesses antioxidant, anti-inflammatory and anti-apoptotic properties. However, despite obvious potential health benefits of bilirubin, its clinical applications are limited by its poor solubility. We recently developed bilirubin nanoparticles (BRNPs) consisting of polyethylene glycol (PEG)-conjugated bilirubin. Here, we sought to investigate whether BRNPs protect against IRI in the liver by preventing oxidative stress. BRNPs exerted potent antioxidant and anti-apoptotic activity in primary hepatocytes exposed to hydrogen peroxide, a precursor of reactive oxygen species (ROS). In a model of hepatic IRI in mice, BRNP preconditioning exerted profound protective effects against hepatocellular injury by reducing oxidative stress, pro-inflammatory cytokine production, and recruitment of neutrophils. They also preferentially accumulated in IRI-induced inflammatory lesions. Collectively, our findings indicate that BRNP preconditioning provides a simple and safe approach that can be easily monitored in the blood like endogenous bilirubin, and could be a promising strategy to protect against IRI in a clinical setting. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Stress preconditioning of spreading depression in the locust CNS.

    Directory of Open Access Journals (Sweden)

    Corinne I Rodgers

    Full Text Available Cortical spreading depression (CSD is closely associated with important pathologies including stroke, seizures and migraine. The mechanisms underlying SD in its various forms are still incompletely understood. Here we describe SD-like events in an invertebrate model, the ventilatory central pattern generator (CPG of locusts. Using K(+ -sensitive microelectrodes, we measured extracellular K(+ concentration ([K(+](o in the metathoracic neuropile of the CPG while monitoring CPG output electromyographically from muscle 161 in the second abdominal segment to investigate the role K(+ in failure of neural circuit operation induced by various stressors. Failure of ventilation in response to different stressors (hyperthermia, anoxia, ATP depletion, Na(+/K(+ ATPase impairment, K(+ injection was associated with a disturbance of CNS ion homeostasis that shares the characteristics of CSD and SD-like events in vertebrates. Hyperthermic failure was preconditioned by prior heat shock (3 h, 45 degrees C and induced-thermotolerance was associated with an increase in the rate of clearance of extracellular K(+ that was not linked to changes in ATP levels or total Na(+/K(+ ATPase activity. Our findings suggest that SD-like events in locusts are adaptive to terminate neural network operation and conserve energy during stress and that they can be preconditioned by experience. We propose that they share mechanisms with CSD in mammals suggesting a common evolutionary origin.

  16. Parallelizable approximate solvers for recursions arising in preconditioning

    Energy Technology Data Exchange (ETDEWEB)

    Shapira, Y. [Israel Inst. of Technology, Haifa (Israel)

    1996-12-31

    For the recursions used in the Modified Incomplete LU (MILU) preconditioner, namely, the incomplete decomposition, forward elimination and back substitution processes, a parallelizable approximate solver is presented. The present analysis shows that the solutions of the recursions depend only weakly on their initial conditions and may be interpreted to indicate that the inexact solution is close, in some sense, to the exact one. The method is based on a domain decomposition approach, suitable for parallel implementations with message passing architectures. It requires a fixed number of communication steps per preconditioned iteration, independently of the number of subdomains or the size of the problem. The overlapping subdomains are either cubes (suitable for mesh-connected arrays of processors) or constructed by the data-flow rule of the recursions (suitable for line-connected arrays with possibly SIMD or vector processors). Numerical examples show that, in both cases, the overhead in the number of iterations required for convergence of the preconditioned iteration is small relatively to the speed-up gained.

  17. Ketamine, but not S(+)-ketamine, blocks ischemic preconditioning in rabbit hearts in vivo

    NARCIS (Netherlands)

    Müllenheim, J.; Frässdorf, J.; Preckel, B.; Thämer, V.; Schlack, W.

    2001-01-01

    BACKGROUND: Ketamine blocks KATP channels in isolated cells and abolishes the cardioprotective effect of ischemic preconditioning in vitro. The authors investigated the effects of ketamine and S(+)-ketamine on ischemic preconditioning in the rabbit heart in vivo. METHODS: In 46

  18. Two-level preconditioned conjugate gradient methods with applications to bubbly flow problems

    NARCIS (Netherlands)

    Tang, J.M.

    2008-01-01

    The Preconditioned Conjugate Gradient (PCG) method is one of the most popular iterative methods for solving large linear systems with a symmetric and positive semi-definite coefficient matrix. However, if the preconditioned coefficient matrix is ill-conditioned, the convergence of the PCG method

  19. Sensory Preconditioning in Newborn Rabbits: From Common to Distinct Odor Memories

    Science.gov (United States)

    Coureaud, Gerard; Tourat, Audrey; Ferreira, Guillaume

    2013-01-01

    This study evaluated whether olfactory preconditioning is functional in newborn rabbits and based on joined or independent memory of odorants. First, after exposure to odorants A+B, the conditioning of A led to high responsiveness to odorant B. Second, responsiveness to B persisted after amnesia of A. Third, preconditioning was also functional…

  20. Develop and implement preconditioning techniques to control face ejection rockbursts for safer mining in seismically hazardous areas

    CSIR Research Space (South Africa)

    Toper, AZ

    1998-01-01

    Full Text Available This research report discusses the development of preconditioning techniques to control face bursts, for safer mining in seismically hazardous areas. Preconditioning involves regularly setting off carefully tailored blasts in the fractured rock...

  1. Algebraic multigrid preconditioning within parallel finite-element solvers for 3-D electromagnetic modelling problems in geophysics

    Science.gov (United States)

    Koldan, Jelena; Puzyrev, Vladimir; de la Puente, Josep; Houzeaux, Guillaume; Cela, José María

    2014-06-01

    We present an elaborate preconditioning scheme for Krylov subspace methods which has been developed to improve the performance and reduce the execution time of parallel node-based finite-element (FE) solvers for 3-D electromagnetic (EM) numerical modelling in exploration geophysics. This new preconditioner is based on algebraic multigrid (AMG) that uses different basic relaxation methods, such as Jacobi, symmetric successive over-relaxation (SSOR) and Gauss-Seidel, as smoothers and the wave front algorithm to create groups, which are used for a coarse-level generation. We have implemented and tested this new preconditioner within our parallel nodal FE solver for 3-D forward problems in EM induction geophysics. We have performed series of experiments for several models with different conductivity structures and characteristics to test the performance of our AMG preconditioning technique when combined with biconjugate gradient stabilized method. The results have shown that, the more challenging the problem is in terms of conductivity contrasts, ratio between the sizes of grid elements and/or frequency, the more benefit is obtained by using this preconditioner. Compared to other preconditioning schemes, such as diagonal, SSOR and truncated approximate inverse, the AMG preconditioner greatly improves the convergence of the iterative solver for all tested models. Also, when it comes to cases in which other preconditioners succeed to converge to a desired precision, AMG is able to considerably reduce the total execution time of the forward-problem code-up to an order of magnitude. Furthermore, the tests have confirmed that our AMG scheme ensures grid-independent rate of convergence, as well as improvement in convergence regardless of how big local mesh refinements are. In addition, AMG is designed to be a black-box preconditioner, which makes it easy to use and combine with different iterative methods. Finally, it has proved to be very practical and efficient in the

  2. IMNN: Information Maximizing Neural Networks

    Science.gov (United States)

    Charnock, Tom; Lavaux, Guilhem; Wandelt, Benjamin D.

    2018-04-01

    This software trains artificial neural networks to find non-linear functionals of data that maximize Fisher information: information maximizing neural networks (IMNNs). As compressing large data sets vastly simplifies both frequentist and Bayesian inference, important information may be inadvertently missed. Likelihood-free inference based on automatically derived IMNN summaries produces summaries that are good approximations to sufficient statistics. IMNNs are robustly capable of automatically finding optimal, non-linear summaries of the data even in cases where linear compression fails: inferring the variance of Gaussian signal in the presence of noise, inferring cosmological parameters from mock simulations of the Lyman-α forest in quasar spectra, and inferring frequency-domain parameters from LISA-like detections of gravitational waveforms. In this final case, the IMNN summary outperforms linear data compression by avoiding the introduction of spurious likelihood maxima.

  3. Is the β phase maximal?

    International Nuclear Information System (INIS)

    Ferrandis, Javier

    2005-01-01

    The current experimental determination of the absolute values of the CKM elements indicates that 2 vertical bar V ub /V cb V us vertical bar =(1-z), with z given by z=0.19+/-0.14. This fact implies that irrespective of the form of the quark Yukawa matrices, the measured value of the SM CP phase β is approximately the maximum allowed by the measured absolute values of the CKM elements. This is β=(π/6-z/3) for γ=(π/3+z/3), which implies α=π/2. Alternatively, assuming that β is exactly maximal and using the experimental measurement sin(2β)=0.726+/-0.037, the phase γ is predicted to be γ=(π/2-β)=66.3 o +/-1.7 o . The maximality of β, if confirmed by near-future experiments, may give us some clues as to the origin of CP violation

  4. Scalable Nonlinear AUC Maximization Methods

    OpenAIRE

    Khalid, Majdi; Ray, Indrakshi; Chitsaz, Hamidreza

    2017-01-01

    The area under the ROC curve (AUC) is a measure of interest in various machine learning and data mining applications. It has been widely used to evaluate classification performance on heavily imbalanced data. The kernelized AUC maximization machines have established a superior generalization ability compared to linear AUC machines because of their capability in modeling the complex nonlinear structure underlying most real world-data. However, the high training complexity renders the kernelize...

  5. Delayed Effects of Remote Limb Ischemic Preconditioning on Maximum Oxygen Consumption, Lactate Release and Pulmonary Function Tests in Athletes and non-Athletes

    Directory of Open Access Journals (Sweden)

    Mahnaz Momeni

    2016-11-01

    Full Text Available Background: Remote Ischemic Preconditioning (RIPC improves exercise performance, and since this phenomenon has two phases, the aim of the current study was to investigate the delayed effects of remote ischemic preconditioning on cardiopulmonary function in athletes and non-athletes. Materials and Methods: 25 male and female students were studied in two main athletes and non-athletes groups. RIPC was induced by using 3 cycles of alternative 5 minutes ischemia and 5 minutes reperfusion at arms of participants. Cardiopulmonary tests were measured before, after and 24 hours after inducing remote ischemic preconditioning. Maximum oxygen consumption (VO2max estimated by using queen steps test. Results: Analysis of data demonstrated that delayed RIPC in non-athletes group caused significant improvement in Forced Expiratory Volume in one second (FEV1 and Maximum Voluntary Ventilation (MVV and noticeable improvement in some other parameters of pulmonary function tests. Moreover, it decreased systolic blood pressure and heart rate and decreased lactate release in both groups especially athletes group but it had no significant effect on VO2max of both groups. Conclusion: Delayed RIPC improves cardiovascular function of athletes and pulmonary function of non-athletes subjects. Thus, it can be considered as a good replacement for doping to improve sports performance of subjects in sports tournaments.

  6. FLOUTING MAXIMS IN INDONESIA LAWAK KLUB CONVERSATION

    Directory of Open Access Journals (Sweden)

    Rahmawati Sukmaningrum

    2017-04-01

    Full Text Available This study aims to identify the types of maxims flouted in the conversation in famous comedy show, Indonesia Lawak Club. Likewise, it also tries to reveal the speakers‘ intention of flouting the maxim in the conversation during the show. The writers use descriptive qualitative method in conducting this research. The data is taken from the dialogue of Indonesia Lawak club and then analyzed based on Grice‘s cooperative principles. The researchers read the dialogue‘s transcripts, identify the maxims, and interpret the data to find the speakers‘ intention for flouting the maxims in the communication. The results show that there are four types of maxims flouted in the dialogue. Those are maxim of quality (23%, maxim of quantity (11%, maxim of manner (31%, and maxim of relevance (35. Flouting the maxims in the conversations is intended to make the speakers feel uncomfortable with the conversation, show arrogances, show disagreement or agreement, and ridicule other speakers.

  7. Effects Of Ischemic Preconditioning On The Renal Ischemia- Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Anyamanesh S

    2003-07-01

    Full Text Available  During kidney and other organ transplantation, the organ to be transplanted, must inevitably remain out of the body with little or no blood perfusion at all for a long period of time (ischemia. These events have been suggested to cause the formation of oxygen- derived free radicals (OFR. Reperfusion (reintroduction of blood flow will further exacerbate the initial damage caused by the ischemic insult and may result in the production of free radicals. The aim of this study was to investigate whether induction of brief periods of renal artery occlusion (ischemic pre¬conditioning, IPC can provide protection from the effects of a subsequent period of ischemia and reperfusion (IR in the rat kidney."nMaterials and Methods: In this regard, 28 white, male rats were randomly and equally divided into four groups: Control (sham- operated, IPC alone, IR alone (30 min ischemia followed by 10 min reperfusion, and IPC- IR. Preconditioning involved the sequential clamping of the right renal artery for 5 min and declamping for 5 min for a total of 3 cycles. To demonstrate the effectiveness of IPC regimen, vitamin E as an endogenous antioxidant and an index of lipid peroxidation was measured by HPLC after its extraction from right renal venous plasma and right renal tissue."nResults: Results of this study showed that the amount of vitamin E of renal tissue and venous plasma in the IR group had a significant decrease when compared to the control group (P< 0.0001. Whereas the amount of this vitamin in both renal tissue and venous plasma of the IPC- IR group was significantly higher than that in the IR group (P< 0.0001, but did not show any significant difference with the control group."nConclusion: In this study, preconditioning method prevented the reduction of the endogenous antioxidant (Vit. E in encountering the following sustained ischemic insult. Therefore, we suggest that ischemic preconditioning can be used to protect the Vit. E level of kidney from its

  8. Ischemic preconditioning fails to confer additional protection against ischemia-reperfusion injury in the hypothyroid rat heart.

    Science.gov (United States)

    Mourouzis, I; Dimopoulos, A; Saranteas, T; Tsinarakis, N; Livadarou, E; Spanou, D; Kokkinos, A D; Xinaris, C; Pantos, C; Cokkinos, D V

    2009-01-01

    There is accumulating evidence showing that ischemic preconditioning (PC) may lose its cardioprotective effect in the diseased states. The present study investigated whether PC can be effective in hypothyroidism, a clinical condition which is common and often accompanies cardiac diseases such as heart failure and myocardial infarction. Hypothyroidism was induced in rats by 3-week administration of 6n-propyl-2-thiouracil in water (0.05 %). Normal and hypothyroid hearts (HYPO) were perfused in Langendorff mode and subjected to 20 min of zero-flow global ischemia and 45 min of reperfusion. A preconditioning protocol (PC) was also applied prior to ischemia. HYPO hearts had significantly improved post-ischemic recovery of left ventricular developed pressure, end-diastolic pressure and reduced lactate dehydrogenase release. Furthermore, phospho-JNK and p38 MAPK levels after ischemia and reperfusion were 4.0 and 3.0 fold lower in HYPO as compared to normal hearts (Phearts. PC improved the post-ischemic recovery of function and reduced the extent of injury in normal hearts but had no additional effect on the hypothyroid hearts. This response, in the preconditioned normal hearts, resulted in 2.5 and 1.8 fold smaller expression of the phospho-JNK and phospho-p38 MAPK levels at the end of reperfusion, as compared to non-PC hearts (Phearts, no additional reduction in the phosphorylation of these kinases was observed after PC. Hypothyroid hearts appear to be tolerant to ischemia-reperfusion injury. This response may be, at least in part, due to the down-regulation of ischemia-reperfusion induced activation of JNKs and p38 MAPK kinases. PC is not associated with further reduction in the activation of these kinases in the hypothyroid hearts and fails to confer added protection in those hearts.

  9. Institutionalized Ignorance as a Precondition for Rational Risk Expertise

    DEFF Research Database (Denmark)

    Merkelsen, Henrik

    2011-01-01

    the lowest organizational level, where concrete risks occur, to the highest organizational level, where the body of professional risk expertise is situated. The article emphasizes the role of knowledge, responsibility, loyalty, and trust as risk-attenuation factors and concludes by suggesting......The present case study seeks to explain the conditions for experts’ rational risk perception by analyzing the institutional contexts that constitute a field of food safety expertise in Denmark. The study highlights the role of risk reporting and how contextual factors affect risk reporting from...... that the preconditions for the expert's rationality may rather be a lack of risk-specific knowledge due to poor risk reporting than a superior level of risk knowledge....

  10. Explicit solution of Calderon preconditioned time domain integral equations

    KAUST Repository

    Ulku, Huseyin Arda

    2013-07-01

    An explicit marching on-in-time (MOT) scheme for solving Calderon-preconditioned time domain integral equations is proposed. The scheme uses Rao-Wilton-Glisson and Buffa-Christiansen functions to discretize the domain and range of the integral operators and a PE(CE)m type linear multistep to march on in time. Unlike its implicit counterpart, the proposed explicit solver requires the solution of an MOT system with a Gram matrix that is sparse and well-conditioned independent of the time step size. Numerical results demonstrate that the explicit solver maintains its accuracy and stability even when the time step size is chosen as large as that typically used by an implicit solver. © 2013 IEEE.

  11. Preconditioned Inexact Newton for Nonlinear Sparse Electromagnetic Imaging

    KAUST Repository

    Desmal, Abdulla; Bagci, Hakan

    2014-01-01

    Newton-type algorithms have been extensively studied in nonlinear microwave imaging due to their quadratic convergence rate and ability to recover images with high contrast values. In the past, Newton methods have been implemented in conjunction with smoothness promoting optimization/regularization schemes. However, this type of regularization schemes are known to perform poorly when applied in imagining domains with sparse content or sharp variations. In this work, an inexact Newton algorithm is formulated and implemented in conjunction with a linear sparse optimization scheme. A novel preconditioning technique is proposed to increase the convergence rate of the optimization problem. Numerical results demonstrate that the proposed framework produces sharper and more accurate images when applied in sparse/sparsified domains.

  12. Preconditioned Inexact Newton for Nonlinear Sparse Electromagnetic Imaging

    KAUST Repository

    Desmal, Abdulla

    2014-05-04

    Newton-type algorithms have been extensively studied in nonlinear microwave imaging due to their quadratic convergence rate and ability to recover images with high contrast values. In the past, Newton methods have been implemented in conjunction with smoothness promoting optimization/regularization schemes. However, this type of regularization schemes are known to perform poorly when applied in imagining domains with sparse content or sharp variations. In this work, an inexact Newton algorithm is formulated and implemented in conjunction with a linear sparse optimization scheme. A novel preconditioning technique is proposed to increase the convergence rate of the optimization problem. Numerical results demonstrate that the proposed framework produces sharper and more accurate images when applied in sparse/sparsified domains.

  13. Preconditioned Inexact Newton for Nonlinear Sparse Electromagnetic Imaging

    KAUST Repository

    Desmal, Abdulla

    2014-01-06

    Newton-type algorithms have been extensively studied in nonlinear microwave imaging due to their quadratic convergence rate and ability to recover images with high contrast values. In the past, Newton methods have been implemented in conjunction with smoothness promoting optimization/regularization schemes. However, this type of regularization schemes are known to perform poorly when applied in imagining domains with sparse content or sharp variations. In this work, an inexact Newton algorithm is formulated and implemented in conjunction with a linear sparse optimization scheme. A novel preconditioning technique is proposed to increase the convergence rate of the optimization problem. Numerical results demonstrate that the proposed framework produces sharper and more accurate images when applied in sparse/sparsified domains.

  14. Natural Preconditioning and Iterative Methods for Saddle Point Systems

    KAUST Repository

    Pestana, Jennifer

    2015-01-01

    © 2015 Society for Industrial and Applied Mathematics. The solution of quadratic or locally quadratic extremum problems subject to linear(ized) constraints gives rise to linear systems in saddle point form. This is true whether in the continuous or the discrete setting, so saddle point systems arising from the discretization of partial differential equation problems, such as those describing electromagnetic problems or incompressible flow, lead to equations with this structure, as do, for example, interior point methods and the sequential quadratic programming approach to nonlinear optimization. This survey concerns iterative solution methods for these problems and, in particular, shows how the problem formulation leads to natural preconditioners which guarantee a fast rate of convergence of the relevant iterative methods. These preconditioners are related to the original extremum problem and their effectiveness - in terms of rapidity of convergence - is established here via a proof of general bounds on the eigenvalues of the preconditioned saddle point matrix on which iteration convergence depends.

  15. Can endurance exercise preconditioning prevention disuse muscle atrophy?

    Directory of Open Access Journals (Sweden)

    Michael P Wiggs

    2015-03-01

    Full Text Available Emerging evidence suggests that exercise training can provide a level of protection against disuse muscle atrophy. Endurance exercise training imposes oxidative, metabolic, and heat stress on skeletal muscle which activates a variety of cellular signaling pathways that ultimately leads to the increased expression of proteins that have been demonstrated to protect muscle from inactivity –induced atrophy. This review will highlight the effect of exercise-induced oxidative stress on endogenous enzymatic antioxidant capacity (i.e., superoxide dismutase, glutathione peroxidase, and catalase, the role of oxidative and metabolic stress on PGC1-α, and finally highlight the effect heat stress and HSP70 induction. Finally, this review will discuss the supporting scientific evidence that these proteins can attenuate muscle atrophy through exercise preconditioning.

  16. Solving large mixed linear models using preconditioned conjugate gradient iteration.

    Science.gov (United States)

    Strandén, I; Lidauer, M

    1999-12-01

    Continuous evaluation of dairy cattle with a random regression test-day model requires a fast solving method and algorithm. A new computing technique feasible in Jacobi and conjugate gradient based iterative methods using iteration on data is presented. In the new computing technique, the calculations in multiplication of a vector by a matrix were recorded to three steps instead of the commonly used two steps. The three-step method was implemented in a general mixed linear model program that used preconditioned conjugate gradient iteration. Performance of this program in comparison to other general solving programs was assessed via estimation of breeding values using univariate, multivariate, and random regression test-day models. Central processing unit time per iteration with the new three-step technique was, at best, one-third that needed with the old technique. Performance was best with the test-day model, which was the largest and most complex model used. The new program did well in comparison to other general software. Programs keeping the mixed model equations in random access memory required at least 20 and 435% more time to solve the univariate and multivariate animal models, respectively. Computations of the second best iteration on data took approximately three and five times longer for the animal and test-day models, respectively, than did the new program. Good performance was due to fast computing time per iteration and quick convergence to the final solutions. Use of preconditioned conjugate gradient based methods in solving large breeding value problems is supported by our findings.

  17. Effect of ozone oxidative preconditioning in preventing early radiation-induced lung injury in rats

    Energy Technology Data Exchange (ETDEWEB)

    Bakkal, B.H. [Department of Radiation Oncology, School of Medicine, Bulent Ecevit University, Kozlu, Zonguldak (Turkey); Gultekin, F.A. [Department of General Surgery, School of Medicine, Bulent Ecevit University, Kozlu, Zonguldak (Turkey); Guven, B. [Department of Biochemistry, School of Medicine, Bulent Ecevit University, Kozlu, Zonguldak (Turkey); Turkcu, U.O. [Mugla School of Health Sciences, Mugla Sitki Kocman University, Mugla (Turkey); Bektas, S. [Department of Pathology, School of Medicine, Bulent Ecevit University, Kozlu, Zonguldak (Turkey); Can, M. [Department of Biochemistry, School of Medicine, Bulent Ecevit University, Kozlu, Zonguldak (Turkey)

    2013-09-27

    Ionizing radiation causes its biological effects mainly through oxidative damage induced by reactive oxygen species. Previous studies showed that ozone oxidative preconditioning attenuated pathophysiological events mediated by reactive oxygen species. As inhalation of ozone induces lung injury, the aim of this study was to examine whether ozone oxidative preconditioning potentiates or attenuates the effects of irradiation on the lung. Rats were subjected to total body irradiation, with or without treatment with ozone oxidative preconditioning (0.72 mg/kg). Serum proinflammatory cytokine levels, oxidative damage markers, and histopathological analysis were compared at 6 and 72 h after total body irradiation. Irradiation significantly increased lung malondialdehyde levels as an end-product of lipoperoxidation. Irradiation also significantly decreased lung superoxide dismutase activity, which is an indicator of the generation of oxidative stress and an early protective response to oxidative damage. Ozone oxidative preconditioning plus irradiation significantly decreased malondialdehyde levels and increased the activity of superoxide dismutase, which might indicate protection of the lung from radiation-induced lung injury. Serum tumor necrosis factor alpha and interleukin-1 beta levels, which increased significantly following total body irradiation, were decreased with ozone oxidative preconditioning. Moreover, ozone oxidative preconditioning was able to ameliorate radiation-induced lung injury assessed by histopathological evaluation. In conclusion, ozone oxidative preconditioning, repeated low-dose intraperitoneal administration of ozone, did not exacerbate radiation-induced lung injury, and, on the contrary, it provided protection against radiation-induced lung damage.

  18. Rural water-supply and sanitation planning: The use of socioeconomic preconditions in project identification

    Science.gov (United States)

    Warner, Dennis B.

    1984-02-01

    Recognition of the socioeconomic preconditions for successful rural water-supply and sanitation projects in developing countries is the key to identifying a new project. Preconditions are the social, economic and technical characteristics defining the project environment. There are two basic types of preconditions: those existing at the time of the initial investigation and those induced by subsequent project activities. Successful project identification is dependent upon an accurate recognition of existing constraints and a carefully tailored package of complementary investments intended to overcome the constraints. This paper discusses the socioeconomic aspects of preconditions in the context of a five-step procedure for project identification. The procedure includes: (1) problem identification; (2) determination of socioeconomic status; (3) technology selection; (4) utilization of support conditions; and (5) benefit estimation. Although the establishment of specific preconditions should be based upon the types of projects likely to be implemented, the paper outlines a number of general relationships regarding favourable preconditions in water and sanitation planning. These relationships are used within the above five-step procedure to develop a set of general guidelines for the application of preconditions in the identification of rural water-supply and sanitation projects.

  19. Effect of ozone oxidative preconditioning in preventing early radiation-induced lung injury in rats

    International Nuclear Information System (INIS)

    Bakkal, B.H.; Gultekin, F.A.; Guven, B.; Turkcu, U.O.; Bektas, S.; Can, M.

    2013-01-01

    Ionizing radiation causes its biological effects mainly through oxidative damage induced by reactive oxygen species. Previous studies showed that ozone oxidative preconditioning attenuated pathophysiological events mediated by reactive oxygen species. As inhalation of ozone induces lung injury, the aim of this study was to examine whether ozone oxidative preconditioning potentiates or attenuates the effects of irradiation on the lung. Rats were subjected to total body irradiation, with or without treatment with ozone oxidative preconditioning (0.72 mg/kg). Serum proinflammatory cytokine levels, oxidative damage markers, and histopathological analysis were compared at 6 and 72 h after total body irradiation. Irradiation significantly increased lung malondialdehyde levels as an end-product of lipoperoxidation. Irradiation also significantly decreased lung superoxide dismutase activity, which is an indicator of the generation of oxidative stress and an early protective response to oxidative damage. Ozone oxidative preconditioning plus irradiation significantly decreased malondialdehyde levels and increased the activity of superoxide dismutase, which might indicate protection of the lung from radiation-induced lung injury. Serum tumor necrosis factor alpha and interleukin-1 beta levels, which increased significantly following total body irradiation, were decreased with ozone oxidative preconditioning. Moreover, ozone oxidative preconditioning was able to ameliorate radiation-induced lung injury assessed by histopathological evaluation. In conclusion, ozone oxidative preconditioning, repeated low-dose intraperitoneal administration of ozone, did not exacerbate radiation-induced lung injury, and, on the contrary, it provided protection against radiation-induced lung damage

  20. A preconditioning nerve lesion inhibits mechanical pain hypersensitivity following subsequent neuropathic injury

    Directory of Open Access Journals (Sweden)

    Wu Ann

    2011-01-01

    Full Text Available Abstract Background A preconditioning stimulus can trigger a neuroprotective phenotype in the nervous system - a preconditioning nerve lesion causes a significant increase in axonal regeneration, and cerebral preconditioning protects against subsequent ischemia. We hypothesized that a preconditioning nerve lesion induces gene/protein modifications, neuronal changes, and immune activation that may affect pain sensation following subsequent nerve injury. We examined whether a preconditioning lesion affects neuropathic pain and neuroinflammation after peripheral nerve injury. Results We found that a preconditioning crush injury to a terminal branch of the sciatic nerve seven days before partial ligation of the sciatic nerve (PSNL; a model of neuropathic pain induced a significant attenuation of pain hypersensitivity, particularly mechanical allodynia. A preconditioning lesion of the tibial nerve induced a long-term significant increase in paw-withdrawal threshold to mechanical stimuli and paw-withdrawal latency to thermal stimuli, after PSNL. A preconditioning lesion of the common peroneal induced a smaller but significant short-term increase in paw-withdrawal threshold to mechanical stimuli, after PSNL. There was no difference between preconditioned and unconditioned animals in neuronal damage and macrophage and T-cell infiltration into the dorsal root ganglia (DRGs or in astrocyte and microglia activation in the spinal dorsal and ventral horns. Conclusions These results suggest that prior exposure to a mild nerve lesion protects against adverse effects of subsequent neuropathic injury, and that this conditioning-induced inhibition of pain hypersensitivity is not dependent on neuroinflammation in DRGs and spinal cord. Identifying the underlying mechanisms may have important implications for the understanding of neuropathic pain due to nerve injury.

  1. Maximal Abelian sets of roots

    CERN Document Server

    Lawther, R

    2018-01-01

    In this work the author lets \\Phi be an irreducible root system, with Coxeter group W. He considers subsets of \\Phi which are abelian, meaning that no two roots in the set have sum in \\Phi \\cup \\{ 0 \\}. He classifies all maximal abelian sets (i.e., abelian sets properly contained in no other) up to the action of W: for each W-orbit of maximal abelian sets we provide an explicit representative X, identify the (setwise) stabilizer W_X of X in W, and decompose X into W_X-orbits. Abelian sets of roots are closely related to abelian unipotent subgroups of simple algebraic groups, and thus to abelian p-subgroups of finite groups of Lie type over fields of characteristic p. Parts of the work presented here have been used to confirm the p-rank of E_8(p^n), and (somewhat unexpectedly) to obtain for the first time the 2-ranks of the Monster and Baby Monster sporadic groups, together with the double cover of the latter. Root systems of classical type are dealt with quickly here; the vast majority of the present work con...

  2. Effect of ischemic preconditioning in skeletal muscle measured by functional magnetic resonance imaging and spectroscopy: a randomized crossover trial

    Directory of Open Access Journals (Sweden)

    Bartko Johann

    2011-06-01

    Full Text Available Abstract Background Nuclear magnetic resonance (NMR imaging and spectroscopy have been applied to assess skeletal muscle oxidative metabolism. Therefore, in-vivo NMR may enable the characterization of ischemia-reperfusion injury. The goal of this study was to evaluate whether NMR could detect the effects of ischemic preconditioning (IPC in healthy subjects. Methods Twenty-three participants were included in two randomized crossover protocols in which the effects of IPC were measured by NMR and muscle force assessments. Leg ischemia was administered for 20 minutes with or without a subsequent impaired reperfusion for 5 minutes (stenosis model. IPC was administered 4 or 48 hours prior to ischemia. Changes in 31phosphate NMR spectroscopy and blood oxygen level-dependent (BOLD signals were recorded. 3-Tesla NMR data were compared to those obtained for isometric muscular strength. Results The phosphocreatine (PCr signal decreased robustly during ischemia and recovered rapidly during reperfusion. In contrast to PCr, the recovery of muscular strength was slow. During post-ischemic stenosis, PCr increased only slightly. The BOLD signal intensity decreased during ischemia, ischemic exercise and post-ischemic stenosis but increased during hyperemic reperfusion. IPC 4 hours prior to ischemia significantly increased the maximal PCr reperfusion signal and mitigated the peak BOLD signal during reperfusion. Conclusions Ischemic preconditioning positively influenced muscle metabolism during reperfusion; this resulted in an increase in PCr production and higher oxygen consumption, thereby mitigating the peak BOLD signal. In addition, an impairment of energy replenishment during the low-flow reperfusion was detected in this model. Thus, functional NMR is capable of characterizing changes in reperfusion and in therapeutic interventions in vivo. Trial Registration ClinicalTrials.gov: NCT00883467

  3. A Preconditioning Technique for First-Order Primal-Dual Splitting Method in Convex Optimization

    Directory of Open Access Journals (Sweden)

    Meng Wen

    2017-01-01

    Full Text Available We introduce a preconditioning technique for the first-order primal-dual splitting method. The primal-dual splitting method offers a very general framework for solving a large class of optimization problems arising in image processing. The key idea of the preconditioning technique is that the constant iterative parameters are updated self-adaptively in the iteration process. We also give a simple and easy way to choose the diagonal preconditioners while the convergence of the iterative algorithm is maintained. The efficiency of the proposed method is demonstrated on an image denoising problem. Numerical results show that the preconditioned iterative algorithm performs better than the original one.

  4. Combining remote ischemic preconditioning and aerobic exercise: a novel adaptation of blood flow restriction exercise.

    Science.gov (United States)

    Sprick, Justin D; Rickards, Caroline A

    2017-11-01

    Remote ischemic preconditioning (RIPC) can attenuate tissue damage sustained by ischemia-reperfusion injury. Blood flow restriction exercise (BFRE) restricts blood flow to exercising muscles. We implemented a novel approach to BFRE with cyclical bouts of blood flow restriction-reperfusion, reflecting the RIPC model. A concern about BFRE, however, is potential amplification of the exercise pressor reflex, which could be unsafe in at-risk populations. We hypothesized that cyclical BFRE would elicit greater increases in sympathetic outflow and arterial pressure than conventional exercise (CE) when performed at the same relative intensity. We also assessed the cerebrovascular responses due to potential implementation of BFRE in stroke rehabilitation. Fourteen subjects performed treadmill exercise at 65-70% maximal heart rate with and without intermittent BFR (4 × 5-min intervals of bilateral thigh-cuff pressure followed by 5-min reperfusion periods). Mean arterial pressure (MAP), plasma norepinephrine (NE), and middle and posterior cerebral artery velocities (MCAv and PCAv) were compared between trials. As expected, BFRE elicited higher concentration NE compared with CE (1249 ± 170 vs. 962 ± 114 pg/ml; P = 0.06). Unexpectedly, however, there were no differences in MAP between conditions (overall P = 0.33), and MAP was 4-5 mmHg lower with BFRE versus CE during the reperfusion periods ( P ≤ 0.05 for reperfusion periods 3 and 4 ). There were no differences in MCAv or PCAv between trials ( P ≥ 0.22), suggesting equivalent cerebrometabolic demand. The exaggerated sympathoexcitatory response with BFRE was not accompanied by higher MAP, likely because of the cyclical reperfusions. This cyclical BFRE paradigm could be adapted to cardiac or stroke rehabilitation, where exercising patients could benefit from the cardio and cerebro protection associated with RIPC. Copyright © 2017 the American Physiological Society.

  5. Maximizing benefits from resource development

    International Nuclear Information System (INIS)

    Skjelbred, B.

    2002-01-01

    The main objectives of Norwegian petroleum policy are to maximize the value creation for the country, develop a national oil and gas industry, and to be at the environmental forefront of long term resource management and coexistence with other industries. The paper presents a graph depicting production and net export of crude oil for countries around the world for 2002. Norway produced 3.41 mill b/d and exported 3.22 mill b/d. Norwegian petroleum policy measures include effective regulation and government ownership, research and technology development, and internationalisation. Research and development has been in five priority areas, including enhanced recovery, environmental protection, deep water recovery, small fields, and the gas value chain. The benefits of internationalisation includes capitalizing on Norwegian competency, exploiting emerging markets and the assurance of long-term value creation and employment. 5 figs

  6. Maximizing synchronizability of duplex networks

    Science.gov (United States)

    Wei, Xiang; Emenheiser, Jeffrey; Wu, Xiaoqun; Lu, Jun-an; D'Souza, Raissa M.

    2018-01-01

    We study the synchronizability of duplex networks formed by two randomly generated network layers with different patterns of interlayer node connections. According to the master stability function, we use the smallest nonzero eigenvalue and the eigenratio between the largest and the second smallest eigenvalues of supra-Laplacian matrices to characterize synchronizability on various duplexes. We find that the interlayer linking weight and linking fraction have a profound impact on synchronizability of duplex networks. The increasingly large inter-layer coupling weight is found to cause either decreasing or constant synchronizability for different classes of network dynamics. In addition, negative node degree correlation across interlayer links outperforms positive degree correlation when most interlayer links are present. The reverse is true when a few interlayer links are present. The numerical results and understanding based on these representative duplex networks are illustrative and instructive for building insights into maximizing synchronizability of more realistic multiplex networks.

  7. VIOLATION OF CONVERSATION MAXIM ON TV ADVERTISEMENTS

    Directory of Open Access Journals (Sweden)

    Desak Putu Eka Pratiwi

    2015-07-01

    Full Text Available Maxim is a principle that must be obeyed by all participants textually and interpersonally in order to have a smooth communication process. Conversation maxim is divided into four namely maxim of quality, maxim of quantity, maxim of relevance, and maxim of manner of speaking. Violation of the maxim may occur in a conversation in which the information the speaker has is not delivered well to his speaking partner. Violation of the maxim in a conversation will result in an awkward impression. The example of violation is the given information that is redundant, untrue, irrelevant, or convoluted. Advertisers often deliberately violate the maxim to create unique and controversial advertisements. This study aims to examine the violation of maxims in conversations of TV ads. The source of data in this research is food advertisements aired on TV media. Documentation and observation methods are applied to obtain qualitative data. The theory used in this study is a maxim theory proposed by Grice (1975. The results of the data analysis are presented with informal method. The results of this study show an interesting fact that the violation of maxim in a conversation found in the advertisement exactly makes the advertisements very attractive and have a high value.

  8. Weighted SGD for ℓp Regression with Randomized Preconditioning*

    Science.gov (United States)

    Yang, Jiyan; Chow, Yin-Lam; Ré, Christopher; Mahoney, Michael W.

    2018-01-01

    In recent years, stochastic gradient descent (SGD) methods and randomized linear algebra (RLA) algorithms have been applied to many large-scale problems in machine learning and data analysis. SGD methods are easy to implement and applicable to a wide range of convex optimization problems. In contrast, RLA algorithms provide much stronger performance guarantees but are applicable to a narrower class of problems. We aim to bridge the gap between these two methods in solving constrained overdetermined linear regression problems—e.g., ℓ2 and ℓ1 regression problems. We propose a hybrid algorithm named pwSGD that uses RLA techniques for preconditioning and constructing an importance sampling distribution, and then performs an SGD-like iterative process with weighted sampling on the preconditioned system.By rewriting a deterministic ℓp regression problem as a stochastic optimization problem, we connect pwSGD to several existing ℓp solvers including RLA methods with algorithmic leveraging (RLA for short).We prove that pwSGD inherits faster convergence rates that only depend on the lower dimension of the linear system, while maintaining low computation complexity. Such SGD convergence rates are superior to other related SGD algorithm such as the weighted randomized Kaczmarz algorithm.Particularly, when solving ℓ1 regression with size n by d, pwSGD returns an approximate solution with ε relative error in the objective value in 𝒪(log n·nnz(A)+poly(d)/ε2) time. This complexity is uniformly better than that of RLA methods in terms of both ε and d when the problem is unconstrained. In the presence of constraints, pwSGD only has to solve a sequence of much simpler and smaller optimization problem over the same constraints. In general this is more efficient than solving the constrained subproblem required in RLA.For ℓ2 regression, pwSGD returns an approximate solution with ε relative error in the objective value and the solution vector measured in

  9. Preconditioned alternating direction method of multipliers for inverse problems with constraints

    International Nuclear Information System (INIS)

    Jiao, Yuling; Jin, Qinian; Lu, Xiliang; Wang, Weijie

    2017-01-01

    We propose a preconditioned alternating direction method of multipliers (ADMM) to solve linear inverse problems in Hilbert spaces with constraints, where the feature of the sought solution under a linear transformation is captured by a possibly non-smooth convex function. During each iteration step, our method avoids solving large linear systems by choosing a suitable preconditioning operator. In case the data is given exactly, we prove the convergence of our preconditioned ADMM without assuming the existence of a Lagrange multiplier. In case the data is corrupted by noise, we propose a stopping rule using information on noise level and show that our preconditioned ADMM is a regularization method; we also propose a heuristic rule when the information on noise level is unavailable or unreliable and give its detailed analysis. Numerical examples are presented to test the performance of the proposed method. (paper)

  10. S2SA preconditioning for the Sn equations with strictly non negative spatial discretization

    International Nuclear Information System (INIS)

    Bruss, D. E.; Morel, J. E.; Ragusa, J. C.

    2013-01-01

    Preconditioners based upon sweeps and diffusion-synthetic acceleration have been constructed and applied to the zeroth and first spatial moments of the 1-D S n transport equation using a strictly non negative nonlinear spatial closure. Linear and nonlinear preconditioners have been analyzed. The effectiveness of various combinations of these preconditioners are compared. In one dimension, nonlinear sweep preconditioning is shown to be superior to linear sweep preconditioning, and DSA preconditioning using nonlinear sweeps in conjunction with a linear diffusion equation is found to be essentially equivalent to nonlinear sweeps in conjunction with a nonlinear diffusion equation. The ability to use a linear diffusion equation has important implications for preconditioning the S n equations with a strictly non negative spatial discretization in multiple dimensions. (authors)

  11. Opioid-induced preconditioning: recent advances and future perspectives.

    Science.gov (United States)

    Peart, Jason N; Gross, Eric R; Gross, Garrett J

    2005-01-01

    Opioids, named by Acheson for compounds with morphine-like actions despite chemically distinct structures, have received much research interest, particularly for their central nervous system (CNS) actions involved in pain management, resulting in thousands of scientific papers focusing on their effects on the CNS and other organ systems. A more recent area which may have great clinical importance concerns the role of opioids, either endogenous or exogenous compounds, in limiting the pathogenesis of ischemia-reperfusion injury in heart and brain. The role of endogenous opioids in hibernation provides tantalizing evidence for the protective potential of opioids against ischemia or hypoxia. Mammalian hibernation, a distinct energy-conserving state, is associated with depletion of energy stores, intracellular acidosis and hypoxia, similar to those which occur during ischemia. However, despite the potentially detrimental cellular state induced with hibernation, the myocardium remains resilient for many months. What accounts for the hypoxia-tolerant state is of great interest. During hibernation, circulating levels of opioid peptides are increased dramatically, and indeed, are considered a "trigger" of hibernation. Furthermore, administration of opioid antagonists can effectively reverse hibernation in mammals. Therefore, it is not surprising that activation of opioid receptors has been demonstrated to preserve cellular status following a hypoxic insult, such as ischemia-reperfusion in many model systems including the intestine [Zhang, Y., Wu, Y.X., Hao, Y.B., Dun, Y. Yang, S.P., 2001. Role of endogenous opioid peptides in protection of ischemic preconditioning in rat small intestine. Life Sci. 68, 1013-1019], skeletal muscle [Addison, P.D., Neligan, P.C., Ashrafpour, H., Khan, A., Zhong, A., Moses, M., Forrest, C.R., Pang, C.Y., 2003. Noninvasive remote ischemic preconditioning for global protection of skeletal muscle against infarction. Am. J. Physiol. Heart Circ

  12. Function and mechanism of toll-like receptors in cerebral ischemic tolerance: from preconditioning to treatment

    OpenAIRE

    Wang, Peng-Fei; Xiong, Xiao-Yi; Chen, Jing; Wang, Yan-Chun; Duan, Wei; Yang, Qing-Wu

    2015-01-01

    Increasing evidence suggests that toll-like receptors (TLRs) play an important role in cerebral ischemia-reperfusion injury. The endogenous ligands released from ischemic neurons activate the TLR signaling pathway, resulting in the production of a large number of inflammatory cytokines, thereby causing secondary inflammation damage following cerebral ischemia. However, the preconditioning for minor cerebral ischemia or the preconditioning with TLR ligands can reduce cerebral ischemic injury b...

  13. Rethinking The Going Concern Assumption As A Pre-Condition For Accounting Measurement

    OpenAIRE

    Saratiel Wedzerai Musvoto; Daan G Gouws

    2011-01-01

    This study compares the principles of the going concern concept against the principles of representational measurement to determine if it is possible to establish foundations of accounting measurement with the going concern concept as a precondition. Representational measurement theory is a theory that establishes measurement in social scientific disciplines such as accounting. The going concern assumption is prescribed as one of the preconditions for measuring the attributes of the elements ...

  14. A systematic approach to robust preconditioning for gradient-based inverse scattering algorithms

    International Nuclear Information System (INIS)

    Nordebo, Sven; Fhager, Andreas; Persson, Mikael; Gustafsson, Mats

    2008-01-01

    This paper presents a systematic approach to robust preconditioning for gradient-based nonlinear inverse scattering algorithms. In particular, one- and two-dimensional inverse problems are considered where the permittivity and conductivity profiles are unknown and the input data consist of the scattered field over a certain bandwidth. A time-domain least-squares formulation is employed and the inversion algorithm is based on a conjugate gradient or quasi-Newton algorithm together with an FDTD-electromagnetic solver. A Fisher information analysis is used to estimate the Hessian of the error functional. A robust preconditioner is then obtained by incorporating a parameter scaling such that the scaled Fisher information has a unit diagonal. By improving the conditioning of the Hessian, the convergence rate of the conjugate gradient or quasi-Newton methods are improved. The preconditioner is robust in the sense that the scaling, i.e. the diagonal Fisher information, is virtually invariant to the numerical resolution and the discretization model that is employed. Numerical examples of image reconstruction are included to illustrate the efficiency of the proposed technique

  15. Accelerating nuclear configuration interaction calculations through a preconditioned block iterative eigensolver

    Science.gov (United States)

    Shao, Meiyue; Aktulga, H. Metin; Yang, Chao; Ng, Esmond G.; Maris, Pieter; Vary, James P.

    2018-01-01

    We describe a number of recently developed techniques for improving the performance of large-scale nuclear configuration interaction calculations on high performance parallel computers. We show the benefit of using a preconditioned block iterative method to replace the Lanczos algorithm that has traditionally been used to perform this type of computation. The rapid convergence of the block iterative method is achieved by a proper choice of starting guesses of the eigenvectors and the construction of an effective preconditioner. These acceleration techniques take advantage of special structure of the nuclear configuration interaction problem which we discuss in detail. The use of a block method also allows us to improve the concurrency of the computation, and take advantage of the memory hierarchy of modern microprocessors to increase the arithmetic intensity of the computation relative to data movement. We also discuss the implementation details that are critical to achieving high performance on massively parallel multi-core supercomputers, and demonstrate that the new block iterative solver is two to three times faster than the Lanczos based algorithm for problems of moderate sizes on a Cray XC30 system.

  16. Transcriptional signature of human adipose tissue-derived stem cells (hASCs) preconditioned for chondrogenesis in hypoxic conditions

    International Nuclear Information System (INIS)

    Pilgaard, L.; Lund, P.; Duroux, M.; Lockstone, H.; Taylor, J.; Emmersen, J.; Fink, T.; Ragoussis, J.; Zachar, V.

    2009-01-01

    Hypoxia is an important factor involved in the control of stem cells. To obtain a better insight into the phenotypical changes brought about by hypoxic preconditioning prior to chondrogenic differentiation; we have investigated growth, colony-forming and chondrogenic capacity, and global transcriptional responses of six adipose tissue-derived stem cell lines expanded at oxygen concentrations ranging from ambient to 1%. The assessment of cell proliferation and colony-forming potential revealed that the hypoxic conditions corresponding to 1% oxygen played a major role. The chondrogenic inducibility, examined by high-density pellet model, however, did not improve on hypoxic preconditioning. While the microarray analysis revealed a distinctive inter-donor variability, the exposure to 1% hypoxia superseded the biological variability and produced a specific expression profile with 2581 significantly regulated genes and substantial functional enrichment in the pathways of cell proliferation and apoptosis. Additionally, exposure to 1% oxygen resulted in upregulation of factors related to angiogenesis and cell growth. In particular, leptin (LEP), the key regulator of body weight and food intake was found to be highly upregulated. In conclusion, the results of this investigation demonstrate the significance of donor demographics and the importance of further studies into the use of regulated oxygen tension as a tool for preparation of ASCs in order to exploit their full potential.

  17. A SEMI-LAGRANGIAN TWO-LEVEL PRECONDITIONED NEWTON-KRYLOV SOLVER FOR CONSTRAINED DIFFEOMORPHIC IMAGE REGISTRATION.

    Science.gov (United States)

    Mang, Andreas; Biros, George

    2017-01-01

    We propose an efficient numerical algorithm for the solution of diffeomorphic image registration problems. We use a variational formulation constrained by a partial differential equation (PDE), where the constraints are a scalar transport equation. We use a pseudospectral discretization in space and second-order accurate semi-Lagrangian time stepping scheme for the transport equations. We solve for a stationary velocity field using a preconditioned, globalized, matrix-free Newton-Krylov scheme. We propose and test a two-level Hessian preconditioner. We consider two strategies for inverting the preconditioner on the coarse grid: a nested preconditioned conjugate gradient method (exact solve) and a nested Chebyshev iterative method (inexact solve) with a fixed number of iterations. We test the performance of our solver in different synthetic and real-world two-dimensional application scenarios. We study grid convergence and computational efficiency of our new scheme. We compare the performance of our solver against our initial implementation that uses the same spatial discretization but a standard, explicit, second-order Runge-Kutta scheme for the numerical time integration of the transport equations and a single-level preconditioner. Our improved scheme delivers significant speedups over our original implementation. As a highlight, we observe a 20 × speedup for a two dimensional, real world multi-subject medical image registration problem.

  18. Sirtinol abrogates late phase of cardiac ischemia preconditioning in rats.

    Science.gov (United States)

    Safari, Fereshteh; Shekarforoosh, Shahnaz; Hashemi, Tahmineh; Namvar Aghdash, Simin; Fekri, Asefeh; Safari, Fatemeh

    2017-07-01

    The aim of this study was to investigate the effect of sirtinol, as an inhibitor of sirtuin NAD-dependent histone deacetylases, on myocardial ischemia reperfusion injury following early and late ischemia preconditioning (IPC). Rats underwent sustained ischemia and reperfusion (IR) alone or proceeded by early or late IPC. Sirtinol (S) was administered before IPC. Arrhythmias were evaluated based on the Lambeth model. Infarct size (IS) was measured using triphenyltetrazolium chloride staining. The transcription level of antioxidant-coding genes was assessed by real-time PCR. In early and late IPC groups, IS and the number of arrhythmia were significantly decreased (P < 0.05 and P < 0.01 vs IR, respectively). In S + early IPC, incidences of arrhythmia and IS were not different compared with the early IPC group. However, in S + late IPC the IS was different from the late IPC group (P < 0.05). In late IPC but not early IPC, transcription levels of catalase (P < 0.01) and Mn-SOD (P < 0.05) increased, although this upregulation was not significant in the S + late IPC group. Our results are consistent with the notion that different mechanisms are responsible for early and late IPC. In addition, sirtuin NAD-dependent histone deacetylases may be implicated in late IPC-induced cardioprotection.

  19. Linear multifrequency-grey acceleration recast for preconditioned Krylov iterations

    International Nuclear Information System (INIS)

    Morel, Jim E.; Brian Yang, T.-Y.; Warsa, James S.

    2007-01-01

    The linear multifrequency-grey acceleration (LMFGA) technique is used to accelerate the iterative convergence of multigroup thermal radiation diffusion calculations in high energy density simulations. Although it is effective and efficient in one-dimensional calculations, the LMFGA method has recently been observed to significantly degrade under certain conditions in multidimensional calculations with large discontinuities in material properties. To address this deficiency, we recast the LMFGA method in terms of a preconditioned system that is solved with a Krylov method (LMFGK). Results are presented demonstrating that the new LMFGK method always requires fewer iterations than the original LMFGA method. The reduction in iteration count increases with both the size of the time step and the inhomogeneity of the problem. However, for reasons later explained, the LMFGK method can cost more per iteration than the LMFGA method, resulting in lower but comparable efficiency in problems with small time steps and weak inhomogeneities. In problems with large time steps and strong inhomogeneities, the LMFGK method is significantly more efficient than the LMFGA method

  20. Cerenkov luminescence tomography based on preconditioning orthogonal matching pursuit

    Science.gov (United States)

    Liu, Haixiao; Hu, Zhenhua; Wang, Kun; Tian, Jie; Yang, Xin

    2015-03-01

    Cerenkov luminescence imaging (CLI) is a novel optical imaging method and has been proved to be a potential substitute of the traditional radionuclide imaging such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). This imaging method inherits the high sensitivity of nuclear medicine and low cost of optical molecular imaging. To obtain the depth information of the radioactive isotope, Cerenkov luminescence tomography (CLT) is established and the 3D distribution of the isotope is reconstructed. However, because of the strong absorption and scatter, the reconstruction of the CLT sources is always converted to an ill-posed linear system which is hard to be solved. In this work, the sparse nature of the light source was taken into account and the preconditioning orthogonal matching pursuit (POMP) method was established to effectively reduce the ill-posedness and obtain better reconstruction accuracy. To prove the accuracy and speed of this algorithm, a heterogeneous numerical phantom experiment and an in vivo mouse experiment were conducted. Both the simulation result and the mouse experiment showed that our reconstruction method can provide more accurate reconstruction result compared with the traditional Tikhonov regularization method and the ordinary orthogonal matching pursuit (OMP) method. Our reconstruction method will provide technical support for the biological application for Cerenkov luminescence.

  1. Deregulation - precondition for distributed energy in the economies in transition

    International Nuclear Information System (INIS)

    Brendow, K.

    2001-01-01

    This paper holds that deregulation, i.e. restructuring, competition and privatisation, is the main precondition for a more pronounced development of distributed power (DP) in the economies in transition in central and eastern Europe. This, then, raises the question how far the electricity, gas, steam and heat generating industries have presently moved on their way towards more market-oriented frameworks, competition and private ownership. A good benchmark for measuring progress is the existence (or lack thereof), and nature, of regulatory regimes enabling fair competition among large centralised and small decentralised power, and between wholesale generators and distributors on the one hand and customers or ''autoproducers'' or power merchants on the other. The paper describes the regulatory models applied or contemplated in the winter 2000/2001 in the various countries of central and eastern Europe and identifies fifteen general issues that require attention and solution. With regard to DP, it concludes that a major upswing is unlikely to occur before 2005-2008. While technological options abound, the institutional frameworks for customer-owned competitive DP systems are only being contemplated at present and only rarely put in place.(author)

  2. FALCON Code Simulation for Verification of Fuel Preconditioning Guideline

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee-Hun; Kwon, Oh-Hyun; Kim, Hong-Jin; Kim, Yong-Hwan [KEPCO Nuclear Fuel Co. Ltd., Daejeon (Korea, Republic of)

    2015-10-15

    The magnitude and rate of power increases are key factors in the PCI failure process. KEPCO NF (KNF) provides operational restrictions called fuel preconditioning guideline (FPG) to mitigate PCI failures. The FPG contains recommended power maneuvering restrictions that should be followed when the KNF supplied fuel is being operated in-reactor. This guideline typically includes controlled power ramp rates, threshold power levels to initiate controlled ramp rates, and restrictions on the operating conditions that impact the potential for PCI failure. The purpose of the FPG is to allow time for stress relaxation to reduce cladding stress buildup during power maneuvers. Two general approaches have been adopted in the development of FPG to mitigate PCI failure in operating commercial reactors. The first approach relies primarily on past operational experience and power ramp test. The second one uses an analytical methodology where a figure-of-merit representative of PCI vulnerability, generally cladding hoop stress, is calculated using a fuel performance code. FALCON simulation can be the identification of a PCI limit parameter, typically cladding hoop stress, which can be used to evaluate a power maneuvering restriction on FPG. The PCI analysis is to assess the cladding hoop stress under various power ramp conditions. Startup ramp rate doesn't affect PCI failure until 50% of rated thermal power.

  3. Inelastic scattering with Chebyshev polynomials and preconditioned conjugate gradient minimization.

    Science.gov (United States)

    Temel, Burcin; Mills, Greg; Metiu, Horia

    2008-03-27

    We describe and test an implementation, using a basis set of Chebyshev polynomials, of a variational method for solving scattering problems in quantum mechanics. This minimum error method (MEM) determines the wave function Psi by minimizing the least-squares error in the function (H Psi - E Psi), where E is the desired scattering energy. We compare the MEM to an alternative, the Kohn variational principle (KVP), by solving the Secrest-Johnson model of two-dimensional inelastic scattering, which has been studied previously using the KVP and for which other numerical solutions are available. We use a conjugate gradient (CG) method to minimize the error, and by preconditioning the CG search, we are able to greatly reduce the number of iterations necessary; the method is thus faster and more stable than a matrix inversion, as is required in the KVP. Also, we avoid errors due to scattering off of the boundaries, which presents substantial problems for other methods, by matching the wave function in the interaction region to the correct asymptotic states at the specified energy; the use of Chebyshev polynomials allows this boundary condition to be implemented accurately. The use of Chebyshev polynomials allows for a rapid and accurate evaluation of the kinetic energy. This basis set is as efficient as plane waves but does not impose an artificial periodicity on the system. There are problems in surface science and molecular electronics which cannot be solved if periodicity is imposed, and the Chebyshev basis set is a good alternative in such situations.

  4. Maximizing ROI (return on information)

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, B.

    2000-05-01

    The role and importance of managing information are discussed, underscoring the importance by quoting from the report of the International Data Corporation, according to which Fortune 500 companies lost $ 12 billion in 1999 due to inefficiencies resulting from intellectual re-work, substandard performance , and inability to find knowledge resources. The report predicts that this figure will rise to $ 31.5 billion by 2003. Key impediments to implementing knowledge management systems are identified as : the cost and human resources requirement of deployment; inflexibility of historical systems to adapt to change; and the difficulty of achieving corporate acceptance of inflexible software products that require changes in 'normal' ways of doing business. The author recommends the use of model, document and rule-independent systems with a document centered interface (DCI), employing rapid application development (RAD) and object technologies and visual model development, which eliminate these problems, making it possible for companies to maximize their return on information (ROI), and achieve substantial savings in implementation costs.

  5. Disk Density Tuning of a Maximal Random Packing.

    Science.gov (United States)

    Ebeida, Mohamed S; Rushdi, Ahmad A; Awad, Muhammad A; Mahmoud, Ahmed H; Yan, Dong-Ming; English, Shawn A; Owens, John D; Bajaj, Chandrajit L; Mitchell, Scott A

    2016-08-01

    We introduce an algorithmic framework for tuning the spatial density of disks in a maximal random packing, without changing the sizing function or radii of disks. Starting from any maximal random packing such as a Maximal Poisson-disk Sampling (MPS), we iteratively relocate, inject (add), or eject (remove) disks, using a set of three successively more-aggressive local operations. We may achieve a user-defined density, either more dense or more sparse, almost up to the theoretical structured limits. The tuned samples are conflict-free, retain coverage maximality, and, except in the extremes, retain the blue noise randomness properties of the input. We change the density of the packing one disk at a time, maintaining the minimum disk separation distance and the maximum domain coverage distance required of any maximal packing. These properties are local, and we can handle spatially-varying sizing functions. Using fewer points to satisfy a sizing function improves the efficiency of some applications. We apply the framework to improve the quality of meshes, removing non-obtuse angles; and to more accurately model fiber reinforced polymers for elastic and failure simulations.

  6. Research report: the effects of hyperbaric oxygen preconditioning on myocardial biomarkers of cardioprotection in patients having coronary artery bypass graft surgery.

    Science.gov (United States)

    Jeysen, Zivan Yogaratnam; Gerard, Laden; Levant, Guvendik; Cowen, Mike; Cale, Alex; Griffin, Steve

    2011-01-01

    We have previously conducted and reported on the primary endpoint of a clinical study which demonstrated that hyperbaric oxygen (HBO2) preconditioning consisting of two 30-minute intervals of 100% oxygen at 2.4 atmospheres absolute (ATA) prior to coronary artery bypass graft (CABG) surgery leads to an improvement in left ventricular stroke work (LVSW) 24 hours following CABG. In that study, 81 patients were randomized to treatment with HBO2 (HBO2; n = 41) or routine treatment (Control Group; n = 40) prior to surgery. The objective of this manuscript is to further report on the result of the exploratory secondary endpoints from that study, specifically the effects of HBO2 preconditioning on biomarkers of myocardial protection. Intraoperative right atrial biopsies were assessed, via an Enzyme Linked ImmunoSorbent Assay (ELISA), for the expression of eNOS and HSP72. In this study, no significant differences were observed between the groups with respect to the quantity of myocardial eNOS and HSP72. However, in the HBO2 Group, following ischemia and reperfusion, the quantities of myocardial eNOS and HSP72 were increased. This suggests that HBO2 preconditioning in this group of patients may be capable of inducing endogenous cardioprotection following ischemic reperfusion injury (IRI).

  7. Modeling of frequency-domain scalar wave equation with the average-derivative optimal scheme based on a multigrid-preconditioned iterative solver

    Science.gov (United States)

    Cao, Jian; Chen, Jing-Bo; Dai, Meng-Xue

    2018-01-01

    An efficient finite-difference frequency-domain modeling of seismic wave propagation relies on the discrete schemes and appropriate solving methods. The average-derivative optimal scheme for the scalar wave modeling is advantageous in terms of the storage saving for the system of linear equations and the flexibility for arbitrary directional sampling intervals. However, using a LU-decomposition-based direct solver to solve its resulting system of linear equations is very costly for both memory and computational requirements. To address this issue, we consider establishing a multigrid-preconditioned BI-CGSTAB iterative solver fit for the average-derivative optimal scheme. The choice of preconditioning matrix and its corresponding multigrid components is made with the help of Fourier spectral analysis and local mode analysis, respectively, which is important for the convergence. Furthermore, we find that for the computation with unequal directional sampling interval, the anisotropic smoothing in the multigrid precondition may affect the convergence rate of this iterative solver. Successful numerical applications of this iterative solver for the homogenous and heterogeneous models in 2D and 3D are presented where the significant reduction of computer memory and the improvement of computational efficiency are demonstrated by comparison with the direct solver. In the numerical experiments, we also show that the unequal directional sampling interval will weaken the advantage of this multigrid-preconditioned iterative solver in the computing speed or, even worse, could reduce its accuracy in some cases, which implies the need for a reasonable control of directional sampling interval in the discretization.

  8. Influence of variable resistance loading on subsequent free weight maximal back squat performance.

    Science.gov (United States)

    Mina, Minas A; Blazevich, Anthony J; Giakas, Giannis; Kay, Anthony D

    2014-10-01

    The purpose of the study was to determine the potentiating effects of variable resistance (VR) exercise during a warm-up on subsequent free-weight resistance (FWR) maximal squat performance. In the first session, 16 recreationally active men (age = 26.0 ± 7.8 years; height = 1.7 ± 0.2 m; mass = 82.6 ± 12.7 kg) were familiarized with the experimental protocols and tested for 1 repetition maximum (1RM) squat lift. The subjects then visited the laboratory on 2 further occasions under either control or experimental conditions. During these conditions, 2 sets of 3 repetitions of either FWR (control) or VR (experimental) squat lifts at 85% of 1RM were performed; during the experimental condition, 35% of the load was generated from band tension. After a 5-minute rest, 1RM, 3D knee joint kinematics, and vastus medialis, vastus lateralis, rectus femoris, and semitendinosus electromyogram (EMG) signals were recorded simultaneously. No subject increased 1RM after FWR, however, 13 of 16 (81%) subjects increased 1RM after VR (mean = 7.7%; p 0.05) or EMG amplitudes (mean = 5.9%; p > 0.05) occurred. Preconditioning using VR significantly increased 1RM without detectable changes in knee extensor muscle activity or knee flexion angle, although eccentric and concentric velocities were reduced. Thus, VR seems to potentiate the neuromuscular system to enhance subsequent maximal lifting performance. Athletes could thus use VR during warm-up routines to maximize squat performance.

  9. Multigrid preconditioning of the generator two-phase mixture balance equations in the Genepi software

    International Nuclear Information System (INIS)

    Belliard, M.; Grandotto, M.

    2003-01-01

    In the framework of the two-phase fluid simulations of the steam generators of pressurized water nuclear reactors, we present in this paper a geometric version of a pseudo-Full MultiGrid (pseudo- FMG) Full Approximation Storage (FAS) preconditioning of balance equations in the GENEPI code. In our application, the 3D steady state flow is reached by a transient computation using a semi-implicit fractional step algorithm for the averaged two-phase mixture balance equations (mass, momentum and energy for the secondary flow). Our application, running on workstation clusters, is based on a CEA code-linker and the PVM package. The difficulties to apply the geometric FAS multigrid method to the momentum and mass balance equations are addressed. The use of a sequential pseudo-FMG FAS twogrid method for both energy and mass/momentum balance equations, using dynamic multigrid cycles, leads to perceptibly improvements in the computation convergences. An original parallel red-black pseudo-FMG FAS three-grid algorithm is presented too. The numerical tests (steam generator mockup simulations) underline the sizable increase in speed of convergence of the computations, essentially for the ones involving a large number of freedom degrees (about 100 thousand cells). The two-phase mixture balance equation residuals are quickly reduced: the reached speed-up stands between 2 and 3 following the number of grids. The effects on the convergence behavior of the numerical parameters are investigated

  10. Conjugate-gradient preconditioning methods for shift-variant PET image reconstruction.

    Science.gov (United States)

    Fessler, J A; Booth, S D

    1999-01-01

    Gradient-based iterative methods often converge slowly for tomographic image reconstruction and image restoration problems, but can be accelerated by suitable preconditioners. Diagonal preconditioners offer some improvement in convergence rate, but do not incorporate the structure of the Hessian matrices in imaging problems. Circulant preconditioners can provide remarkable acceleration for inverse problems that are approximately shift-invariant, i.e., for those with approximately block-Toeplitz or block-circulant Hessians. However, in applications with nonuniform noise variance, such as arises from Poisson statistics in emission tomography and in quantum-limited optical imaging, the Hessian of the weighted least-squares objective function is quite shift-variant, and circulant preconditioners perform poorly. Additional shift-variance is caused by edge-preserving regularization methods based on nonquadratic penalty functions. This paper describes new preconditioners that approximate more accurately the Hessian matrices of shift-variant imaging problems. Compared to diagonal or circulant preconditioning, the new preconditioners lead to significantly faster convergence rates for the unconstrained conjugate-gradient (CG) iteration. We also propose a new efficient method for the line-search step required by CG methods. Applications to positron emission tomography (PET) illustrate the method.

  11. Role of morphine preconditioning and nitric oxide following brain ischemia reperfusion injury in mice

    Directory of Open Access Journals (Sweden)

    Maedeh Arabian

    2015-01-01

    Full Text Available Objective(s: Morphine dependence (MD potently protects heart against ischemia reperfusion (IR injury through specific signaling mechanisms, which are different from the pathways involved in acute morphine treatment or classical preconditioning. Since opioid receptor density changes post cerebral ischemia strongly correlated with brain histological damage, in the present study, we tried to elucidate the possible role of opioid receptors in IR injury among morphine-dependent mice. Materials and Methods: Accordingly, incremental doses (10 mg/kg/day to 30 mg/kg/day of morphine sulphate were subcutaneously administered for 5 days before global brain ischemia induction through bilateral common carotid artery occlusion. Animals were received naloxone (5 mg/kg or L-NAME (20 mg/kg 30 min after the last morphine dose. Twenty four hr after the ischemia induction, Retention trial of passive avoidance test and western blot analysis were done. histological analysis (TUNEL and NISSL staining performed 72 hr after ischemia. Results: MD improved post ischemia memory performance (P

  12. Does mental exertion alter maximal muscle activation?

    Directory of Open Access Journals (Sweden)

    Vianney eRozand

    2014-09-01

    Full Text Available Mental exertion is known to impair endurance performance, but its effects on neuromuscular function remain unclear. The purpose of this study was to test the hypothesis that mental exertion reduces torque and muscle activation during intermittent maximal voluntary contractions of the knee extensors. Ten subjects performed in a randomized order three separate mental exertion conditions lasting 27 minutes each: i high mental exertion (incongruent Stroop task, ii moderate mental exertion (congruent Stroop task, iii low mental exertion (watching a movie. In each condition, mental exertion was combined with ten intermittent maximal voluntary contractions of the knee extensor muscles (one maximal voluntary contraction every 3 minutes. Neuromuscular function was assessed using electrical nerve stimulation. Maximal voluntary torque, maximal muscle activation and other neuromuscular parameters were similar across mental exertion conditions and did not change over time. These findings suggest that mental exertion does not affect neuromuscular function during intermittent maximal voluntary contractions of the knee extensors.

  13. AUC-Maximizing Ensembles through Metalearning.

    Science.gov (United States)

    LeDell, Erin; van der Laan, Mark J; Petersen, Maya

    2016-05-01

    Area Under the ROC Curve (AUC) is often used to measure the performance of an estimator in binary classification problems. An AUC-maximizing classifier can have significant advantages in cases where ranking correctness is valued or if the outcome is rare. In a Super Learner ensemble, maximization of the AUC can be achieved by the use of an AUC-maximining metalearning algorithm. We discuss an implementation of an AUC-maximization technique that is formulated as a nonlinear optimization problem. We also evaluate the effectiveness of a large number of different nonlinear optimization algorithms to maximize the cross-validated AUC of the ensemble fit. The results provide evidence that AUC-maximizing metalearners can, and often do, out-perform non-AUC-maximizing metalearning methods, with respect to ensemble AUC. The results also demonstrate that as the level of imbalance in the training data increases, the Super Learner ensemble outperforms the top base algorithm by a larger degree.

  14. Maximizing car insurance online sales by developing superior webshop

    OpenAIRE

    Pylväs, Paula

    2014-01-01

    The purpose of this thesis work was to investigate what kind of webshop and what kind of improvements would increase customer satisfaction and maximize car insurance online sales by volume and by value. Main measure for this is the conversion rate, percentage of the potential buyers entering the site who actually make a purchase.

  15. Hyperbaric oxygen preconditioning protects against traumatic brain injury at high altitude.

    Science.gov (United States)

    Hu, S L; Hu, R; Li, F; Liu, Z; Xia, Y Z; Cui, G Y; Feng, H

    2008-01-01

    Recent studies have shown that preconditioning with hyperbaric oxygen (HBO) can reduce ischemic and hemorrhagic brain injury. We investigated effects of HBO preconditioning on traumatic brain injury (TBI) at high altitude and examined the role of matrix metalloproteinase-9 (MMP-9) in such protection. Rats were randomly divided into 3 groups: HBO preconditioning group (HBOP; n = 13), high-altitude group (HA; n = 13), and high-altitude sham operation group (HASO; n = 13). All groups were subjected to head trauma by weight-drop device, except for HASO group. HBOP rats received 5 sessions of HBO preconditioning (2.5 ATA, 100% oxygen, 1 h daily) and then were kept in hypobaric chamber at 0.6 ATA (to simulate pressure at 4000m altitude) for 3 days before operation. HA rats received control pretreatment (1 ATA, room air, 1 h daily), then followed the same procedures as HBOP group. HASO rats were subjected to skull opening only without brain injury. Twenty-four hours after TBI, 7 rats from each group were examined for neurological function and brain water content; 6 rats from each group were killed for analysis by H&E staining and immunohistochemistry. Neurological outcome in HBOP group (0.71 +/- 0.49) was better than HA group (1.57 +/- 0.53; p < 0.05). Preconditioning with HBO significantly reduced percentage of brain water content (86.24 +/- 0.52 vs. 84.60 +/- 0.37; p < 0.01). Brain morphology and structure seen by light microscopy was diminished in HA group, while fewer pathological injuries occurred in HBOP group. Compared to HA group, pretreatment with HBO significantly reduced the number of MMP-9-positive cells (92.25 +/- 8.85 vs. 74.42 +/- 6.27; p < 0.01). HBO preconditioning attenuates TBI in rats at high altitude. Decline in MMP-9 expression may contribute to HBO preconditioning-induced protection of brain tissue against TBI.

  16. On maximal massive 3D supergravity

    OpenAIRE

    Bergshoeff , Eric A; Hohm , Olaf; Rosseel , Jan; Townsend , Paul K

    2010-01-01

    ABSTRACT We construct, at the linearized level, the three-dimensional (3D) N = 4 supersymmetric " general massive supergravity " and the maximally supersymmetric N = 8 " new massive supergravity ". We also construct the maximally supersymmetric linearized N = 7 topologically massive supergravity, although we expect N = 6 to be maximal at the non-linear level. (Bergshoeff, Eric A) (Hohm, Olaf) (Rosseel, Jan) P.K.Townsend@da...

  17. Inclusive Fitness Maximization:An Axiomatic Approach

    OpenAIRE

    Okasha, Samir; Weymark, John; Bossert, Walter

    2014-01-01

    Kin selection theorists argue that evolution in social contexts will lead organisms to behave as if maximizing their inclusive, as opposed to personal, fitness. The inclusive fitness concept allows biologists to treat organisms as akin to rational agents seeking to maximize a utility function. Here we develop this idea and place it on a firm footing by employing a standard decision-theoretic methodology. We show how the principle of inclusive fitness maximization and a related principle of qu...

  18. Preconditioning with endoplasmic reticulum stress ameliorates endothelial cell inflammation.

    Science.gov (United States)

    Leonard, Antony; Paton, Adrienne W; El-Quadi, Monaliza; Paton, James C; Fazal, Fabeha

    2014-01-01

    Endoplasmic Reticulum (ER) stress, caused by disturbance in ER homeostasis, has been implicated in several pathological conditions such as ischemic injury, neurodegenerative disorders, metabolic diseases and more recently in inflammatory conditions. Our present study aims at understanding the role of ER stress in endothelial cell (EC) inflammation, a critical event in the pathogenesis of acute lung injury (ALI). We found that preconditioning human pulmonary artery endothelial cells (HPAEC) to ER stress either by depleting ER chaperone and signaling regulator BiP using siRNA, or specifically cleaving (inactivating) BiP using subtilase cytotoxin (SubAB), alleviates EC inflammation. The two approaches adopted to abrogate BiP function induced ATF4 protein expression and the phosphorylation of eIF2α, both markers of ER stress, which in turn resulted in blunting the activation of NF-κB, and restoring endothelial barrier integrity. Pretreatment of HPAEC with BiP siRNA inhibited thrombin-induced IκBα degradation and its resulting downstream signaling pathway involving NF-κB nuclear translocation, DNA binding, phosphorylation at serine536, transcriptional activation and subsequent expression of adhesion molecules. However, TNFα-mediated NF-κB signaling was unaffected upon BiP knockdown. In an alternative approach, SubAB-mediated inactivation of NF-κB was independent of IκBα degradation. Mechanistic analysis revealed that pretreatment of EC with SubAB interfered with the binding of the liberated NF-κB to the DNA, thereby resulting in reduced expression of adhesion molecules, cytokines and chemokines. In addition, both knockdown and inactivation of BiP stimulated actin cytoskeletal reorganization resulting in restoration of endothelial permeability. Together our studies indicate that BiP plays a central role in EC inflammation and injury via its action on NF-κB activation and regulation of vascular permeability.

  19. Preconditioning of Interplanetary Space Due to Transient CME Disturbances

    International Nuclear Information System (INIS)

    Temmer, M.; Reiss, M. A.; Hofmeister, S. J.; Veronig, A. M.; Nikolic, L.

    2017-01-01

    Interplanetary space is characteristically structured mainly by high-speed solar wind streams emanating from coronal holes and transient disturbances such as coronal mass ejections (CMEs). While high-speed solar wind streams pose a continuous outflow, CMEs abruptly disrupt the rather steady structure, causing large deviations from the quiet solar wind conditions. For the first time, we give a quantification of the duration of disturbed conditions (preconditioning) for interplanetary space caused by CMEs. To this aim, we investigate the plasma speed component of the solar wind and the impact of in situ detected interplanetary CMEs (ICMEs), compared to different background solar wind models (ESWF, WSA, persistence model) for the time range 2011–2015. We quantify in terms of standard error measures the deviations between modeled background solar wind speed and observed solar wind speed. Using the mean absolute error, we obtain an average deviation for quiet solar activity within a range of 75.1–83.1 km s −1 . Compared to this baseline level, periods within the ICME interval showed an increase of 18%–32% above the expected background, and the period of two days after the ICME displayed an increase of 9%–24%. We obtain a total duration of enhanced deviations over about three and up to six days after the ICME start, which is much longer than the average duration of an ICME disturbance itself (∼1.3 days), concluding that interplanetary space needs ∼2–5 days to recover from the impact of ICMEs. The obtained results have strong implications for studying CME propagation behavior and also for space weather forecasting.

  20. Preconditioning of Interplanetary Space Due to Transient CME Disturbances

    Energy Technology Data Exchange (ETDEWEB)

    Temmer, M.; Reiss, M. A.; Hofmeister, S. J.; Veronig, A. M. [Institute of Physics, University of Graz, Universitätsplatz 5/II, A-8010 Graz (Austria); Nikolic, L., E-mail: manuela.temmer@uni-graz.at [Canadian Hazards Information Service, Natural Resources Canada, 2617 Anderson Road, Ottawa, Ontario K1A 0Y3 (Canada)

    2017-02-01

    Interplanetary space is characteristically structured mainly by high-speed solar wind streams emanating from coronal holes and transient disturbances such as coronal mass ejections (CMEs). While high-speed solar wind streams pose a continuous outflow, CMEs abruptly disrupt the rather steady structure, causing large deviations from the quiet solar wind conditions. For the first time, we give a quantification of the duration of disturbed conditions (preconditioning) for interplanetary space caused by CMEs. To this aim, we investigate the plasma speed component of the solar wind and the impact of in situ detected interplanetary CMEs (ICMEs), compared to different background solar wind models (ESWF, WSA, persistence model) for the time range 2011–2015. We quantify in terms of standard error measures the deviations between modeled background solar wind speed and observed solar wind speed. Using the mean absolute error, we obtain an average deviation for quiet solar activity within a range of 75.1–83.1 km s{sup −1}. Compared to this baseline level, periods within the ICME interval showed an increase of 18%–32% above the expected background, and the period of two days after the ICME displayed an increase of 9%–24%. We obtain a total duration of enhanced deviations over about three and up to six days after the ICME start, which is much longer than the average duration of an ICME disturbance itself (∼1.3 days), concluding that interplanetary space needs ∼2–5 days to recover from the impact of ICMEs. The obtained results have strong implications for studying CME propagation behavior and also for space weather forecasting.

  1. Angiotensin II Removes Kidney Resistance Conferred by Ischemic Preconditioning

    Directory of Open Access Journals (Sweden)

    Hee-Seong Jang

    2014-01-01

    Full Text Available Ischemic preconditioning (IPC by ischemia/reperfusion (I/R renders resistance to the kidney. Strong IPC triggers kidney fibrosis, which is involved in angiotensin II (AngII and its type 1 receptor (AT1R signaling. Here, we investigated the role of AngII/AT1R signal pathway in the resistance of IPC kidneys to subsequent I/R injury. IPC of kidneys was generated by 30 minutes of bilateral renal ischemia and 8 days of reperfusion. Sham-operation was performed to generate control (non-IPC mice. To examine the roles of AngII and AT1R in IPC kidneys to subsequent I/R, IPC kidneys were subjected to either 30 minutes of bilateral kidney ischemia or sham-operation following treatment with AngII, losartan (AT1R blocker, or AngII plus losartan. IPC kidneys showed fibrotic changes, decreased AngII, and increased AT1R expression. I/R dramatically increased plasma creatinine concentrations in non-IPC mice, but not in IPC mice. AngII treatment in IPC mice resulted in enhanced morphological damage, oxidative stress, and inflammatory responses, with functional impairment, whereas losartan treatment reversed these effects. However, AngII treatment in non-IPC mice did not change I/R-induced injury. AngII abolished the resistance of IPC kidneys to subsequent I/R via the enhancement of oxidative stress and inflammatory responses, suggesting that the AngII/AT1R signaling pathway is associated with outcome in injury-experienced kidney.

  2. Activity versus outcome maximization in time management.

    Science.gov (United States)

    Malkoc, Selin A; Tonietto, Gabriela N

    2018-04-30

    Feeling time-pressed has become ubiquitous. Time management strategies have emerged to help individuals fit in more of their desired and necessary activities. We provide a review of these strategies. In doing so, we distinguish between two, often competing, motives people have in managing their time: activity maximization and outcome maximization. The emerging literature points to an important dilemma: a given strategy that maximizes the number of activities might be detrimental to outcome maximization. We discuss such factors that might hinder performance in work tasks and enjoyment in leisure tasks. Finally, we provide theoretically grounded recommendations that can help balance these two important goals in time management. Published by Elsevier Ltd.

  3. On the maximal superalgebras of supersymmetric backgrounds

    International Nuclear Information System (INIS)

    Figueroa-O'Farrill, Jose; Hackett-Jones, Emily; Moutsopoulos, George; Simon, Joan

    2009-01-01

    In this paper we give a precise definition of the notion of a maximal superalgebra of certain types of supersymmetric supergravity backgrounds, including the Freund-Rubin backgrounds, and propose a geometric construction extending the well-known construction of its Killing superalgebra. We determine the structure of maximal Lie superalgebras and show that there is a finite number of isomorphism classes, all related via contractions from an orthosymplectic Lie superalgebra. We use the structure theory to show that maximally supersymmetric waves do not possess such a maximal superalgebra, but that the maximally supersymmetric Freund-Rubin backgrounds do. We perform the explicit geometric construction of the maximal superalgebra of AdS 4 X S 7 and find that it is isomorphic to osp(1|32). We propose an algebraic construction of the maximal superalgebra of any background asymptotic to AdS 4 X S 7 and we test this proposal by computing the maximal superalgebra of the M2-brane in its two maximally supersymmetric limits, finding agreement.

  4. Task-oriented maximally entangled states

    International Nuclear Information System (INIS)

    Agrawal, Pankaj; Pradhan, B

    2010-01-01

    We introduce the notion of a task-oriented maximally entangled state (TMES). This notion depends on the task for which a quantum state is used as the resource. TMESs are the states that can be used to carry out the task maximally. This concept may be more useful than that of a general maximally entangled state in the case of a multipartite system. We illustrate this idea by giving an operational definition of maximally entangled states on the basis of communication tasks of teleportation and superdense coding. We also give examples and a procedure to obtain such TMESs for n-qubit systems.

  5. Efficient maximal Poisson-disk sampling and remeshing on surfaces

    KAUST Repository

    Guo, Jianwei; Yan, Dongming; Jia, Xiaohong; Zhang, Xiaopeng

    2015-01-01

    Poisson-disk sampling is one of the fundamental research problems in computer graphics that has many applications. In this paper, we study the problem of maximal Poisson-disk sampling on mesh surfaces. We present a simple approach that generalizes the 2D maximal sampling framework to surfaces. The key observation is to use a subdivided mesh as the sampling domain for conflict checking and void detection. Our approach improves the state-of-the-art approach in efficiency, quality and the memory consumption.

  6. Efficient maximal Poisson-disk sampling and remeshing on surfaces

    KAUST Repository

    Guo, Jianwei

    2015-02-01

    Poisson-disk sampling is one of the fundamental research problems in computer graphics that has many applications. In this paper, we study the problem of maximal Poisson-disk sampling on mesh surfaces. We present a simple approach that generalizes the 2D maximal sampling framework to surfaces. The key observation is to use a subdivided mesh as the sampling domain for conflict checking and void detection. Our approach improves the state-of-the-art approach in efficiency, quality and the memory consumption.

  7. Adaptive maximal poisson-disk sampling on surfaces

    KAUST Repository

    Yan, Dongming

    2012-01-01

    In this paper, we study the generation of maximal Poisson-disk sets with varying radii on surfaces. Based on the concepts of power diagram and regular triangulation, we present a geometric analysis of gaps in such disk sets on surfaces, which is the key ingredient of the adaptive maximal Poisson-disk sampling framework. Moreover, we adapt the presented sampling framework for remeshing applications. Several novel and efficient operators are developed for improving the sampling/meshing quality over the state-of-theart. © 2012 ACM.

  8. Insight on stem cell preconditioning and instructive biomaterials to enhance cell adhesion, retention, and engraftment for tissue repair.

    Science.gov (United States)

    Shafiq, Muhammad; Jung, Youngmee; Kim, Soo Hyun

    2016-06-01

    Stem cells are a promising solution for the treatment of a variety of diseases. However, the limited survival and engraftment of transplanted cells due to a hostile ischemic environment is a bottleneck for effective utilization and commercialization. Within this environment, the majority of transplanted cells undergo apoptosis prior to participating in lineage differentiation and cellular integration. Therefore, in order to maximize the clinical utility of stem/progenitor cells, strategies must be employed to increase their adhesion, retention, and engraftment in vivo. Here, we reviewed key strategies that are being adopted to enhance the survival, retention, and engraftment of transplanted stem cells through the manipulation of both the stem cells and the surrounding environment. We describe how preconditioning of cells or cell manipulations strategies can enhance stem cell survival and engraftment after transplantation. We also discuss how biomaterials can enhance the function of stem cells for effective tissue regeneration. Biomaterials can incorporate or mimic extracellular function (ECM) function and enhance survival or differentiation of transplanted cells in vivo. Biomaterials can also promote angiogenesis, enhance engraftment and differentiation, and accelerate electromechanical integration of transplanted stem cells. Insight gained from this review may direct the development of future investigations and clinical trials. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Maximization of regional probabilities using Optimal Surface Graphs

    DEFF Research Database (Denmark)

    Arias Lorza, Andres M.; Van Engelen, Arna; Petersen, Jens

    2018-01-01

    Purpose: We present a segmentation method that maximizes regional probabilities enclosed by coupled surfaces using an Optimal Surface Graph (OSG) cut approach. This OSG cut determines the globally optimal solution given a graph constructed around an initial surface. While most methods for vessel...... wall segmentation only use edge information, we show that maximizing regional probabilities using an OSG improves the segmentation results. We applied this to automatically segment the vessel wall of the carotid artery in magnetic resonance images. Methods: First, voxel-wise regional probability maps...... were obtained using a Support Vector Machine classifier trained on local image features. Then, the OSG segments the regions which maximizes the regional probabilities considering smoothness and topological constraints. Results: The method was evaluated on 49 carotid arteries from 30 subjects...

  10. Integrity of Cerebellar Fastigial Nucleus Intrinsic Neurons Is Critical for the Global Ischemic Preconditioning

    Directory of Open Access Journals (Sweden)

    Eugene V. Golanov

    2017-09-01

    Full Text Available Excitation of intrinsic neurons of cerebellar fastigial nucleus (FN renders brain tolerant to local and global ischemia. This effect reaches a maximum 72 h after the stimulation and lasts over 10 days. Comparable neuroprotection is observed following sublethal global brain ischemia, a phenomenon known as preconditioning. We hypothesized that FN may participate in the mechanisms of ischemic preconditioning as a part of the intrinsic neuroprotective mechanism. To explore potential significance of FN neurons in brain ischemic tolerance we lesioned intrinsic FN neurons with excitotoxin ibotenic acid five days before exposure to 20 min four-vessel occlusion (4-VO global ischemia while analyzing neuronal damage in Cornu Ammoni area 1 (CA1 hippocampal area one week later. In FN-lesioned animals, loss of CA1 cells was higher by 22% compared to control (phosphate buffered saline (PBS-injected animals. Moreover, lesion of FN neurons increased morbidity following global ischemia by 50%. Ablation of FN neurons also reversed salvaging effects of five-minute ischemic preconditioning on CA1 neurons and morbidity, while ablation of cerebellar dentate nucleus neurons did not change effect of ischemic preconditioning. We conclude that FN is an important part of intrinsic neuroprotective system, which participates in ischemic preconditioning and may participate in naturally occurring neuroprotection, such as “diving response”.

  11. Time-domain full waveform inversion using the gradient preconditioning based on transmitted waves energy

    KAUST Repository

    Zhang, Xiao-bo

    2017-06-01

    The gradient preconditioning approach based on seismic wave energy can effectively avoid the huge storage consumption in the gradient preconditioning algorithms based on Hessian matrices in time-domain full waveform inversion (FWI), but the accuracy is affected by the energy of reflected waves when strong reflectors are present in velocity model. To address this problem, we propose a gradient preconditioning method, which scales the gradient based on the energy of the “approximated transmitted wavefield” simulated by the nonreflecting acoustic wave equation. The method does not require computing or storing the Hessian matrix or its inverse. Furthermore, it can effectively eliminate the effects caused by geometric diffusion and non-uniformity illumination on gradient. The results of model experiments confirm that the time-domain FWI using the gradient preconditioning based on transmitted waves energy can achieve higher inversion precision for high-velocity body and the deep strata below when compared with using the gradient preconditioning based on seismic waves energy.

  12. Super-low dose endotoxin pre-conditioning exacerbates sepsis mortality.

    Science.gov (United States)

    Chen, Keqiang; Geng, Shuo; Yuan, Ruoxi; Diao, Na; Upchurch, Zachary; Li, Liwu

    2015-04-01

    Sepsis mortality varies dramatically in individuals of variable immune conditions, with poorly defined mechanisms. This phenomenon complements the hypothesis that innate immunity may adopt rudimentary memory, as demonstrated in vitro with endotoxin priming and tolerance in cultured monocytes. However, previous in vivo studies only examined the protective effect of endotoxin tolerance in the context of sepsis. In sharp contrast, we report herein that pre-conditionings with super-low or low dose endotoxin lipopolysaccharide (LPS) cause strikingly opposite survival outcomes. Mice pre-conditioned with super-low dose LPS experienced severe tissue damage, inflammation, increased bacterial load in circulation, and elevated mortality when they were subjected to cecal-ligation and puncture (CLP). This is in opposite to the well-reported protective phenomenon with CLP mice pre-conditioned with low dose LPS. Mechanistically, we demonstrated that super-low and low dose LPS differentially modulate the formation of neutrophil extracellular trap (NET) in neutrophils. Instead of increased ERK activation and NET formation in neutrophils pre-conditioned with low dose LPS, we observed significantly reduced ERK activation and compromised NET generation in neutrophils pre-conditioned with super-low dose LPS. Collectively, our findings reveal a novel mechanism potentially responsible for the dynamic programming of innate immunity in vivo as it relates to sepsis risks.

  13. Super-low Dose Endotoxin Pre-conditioning Exacerbates Sepsis Mortality

    Directory of Open Access Journals (Sweden)

    Keqiang Chen

    2015-04-01

    Full Text Available Sepsis mortality varies dramatically in individuals of variable immune conditions, with poorly defined mechanisms. This phenomenon complements the hypothesis that innate immunity may adopt rudimentary memory, as demonstrated in vitro with endotoxin priming and tolerance in cultured monocytes. However, previous in vivo studies only examined the protective effect of endotoxin tolerance in the context of sepsis. In sharp contrast, we report herein that pre-conditioning with super-low or low dose endotoxin lipopolysaccharide (LPS cause strikingly opposite survival outcomes. Mice pre-conditioned with super-low dose LPS experienced severe tissue damage, inflammation, increased bacterial load in circulation, and elevated mortality when they were subjected to cecal-ligation and puncture (CLP. This is in contrast to the well-reported protective phenomenon with CLP mice pre-conditioned with low dose LPS. Mechanistically, we demonstrated that super-low and low dose LPS differentially modulate the formation of neutrophil extracellular trap (NET in neutrophils. Instead of increased ERK activation and NET formation in neutrophils pre-conditioned with low dose LPS, we observed significantly reduced ERK activation and compromised NET generation in neutrophils pre-conditioned with super-low dose LPS. Collectively, our findings reveal a mechanism potentially responsible for the dynamic programming of innate immunity in vivo as it relates to sepsis risks.

  14. Involvement of CCR-2 chemokine receptor activation in ischemic preconditioning and postconditioning of brain in mice.

    Science.gov (United States)

    Rehni, Ashish K; Singh, Thakur Gurjeet

    2012-10-01

    The present study has been designed to investigate the potential role of CCR-2 chemokine receptor in ischemic preconditioning as well as postconditioning induced reversal of ischemia-reperfusion injury in mouse brain. Bilateral carotid artery occlusion of 17 min followed by reperfusion for 24h was employed in present study to produce ischemia and reperfusion induced cerebral injury in mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was evaluated using elevated plus-maze test and Morris water maze test. Rota rod test was employed to assess motor incoordination. Bilateral carotid artery occlusion followed by reperfusion produced cerebral infarction and impaired memory and motor co-ordination. Three preceding episodes of bilateral carotid artery occlusion for 1 min and reperfusion of 1 min were employed to elicit ischemic preconditioning of brain, while three episodes of bilateral carotid artery occlusion for 10s and reperfusion of 10s immediately after the completion of were employed to elicit ischemic postconditioning of brain. Both prior ischemic preconditioning as well as ischemic postconditioning immediately after global cerebral ischemia prevented markedly ischemia-reperfusion-induced cerebral injury as measured in terms of infarct size, loss of memory and motor coordination. RS 102895, a selective CCR-2 chemokine receptor antagonist, attenuated the neuroprotective effect of both the ischemic preconditioning as well as postconditioning. It is concluded that the neuroprotective effect of both ischemic preconditioning as well as ischemic postconditioning may involve the activation of CCR-2 chemokine receptors. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. The role of adenosine in preconditioning by brief pressure overload in rats.

    Science.gov (United States)

    Huang, Cheng-Hsiung; Tsai, Shen-Kou; Chiang, Shu-Chiung; Lai, Chang-Chi; Weng, Zen-Chung

    2015-08-01

    Brief pressure overload of the left ventricle reduced myocardial infarct (MI) size in rabbits has been previously reported. Its effects in other species are not known. This study investigates effects of pressure overload and the role of adenosine in rats in this study. MI was induced by 40-minute occlusion of the left anterior descending coronary artery followed by 3-hour reperfusion. MI size was determined by triphenyl tetrazolium chloride staining. Brief pressure overload was induced by two 10-minute episodes of partial snaring of the ascending aorta. Systolic left ventricular pressure was raised 50% above the baseline value. Ischemic preconditioning was elicited by two 10-minute coronary artery occlusions. The MI size (mean ± standard deviation), expressed as percentage of area at risk, was significantly reduced in the pressure overload group as well as in the ischemic preconditioning group (17.4 ± 3.0% and 18.2 ± 1.5% vs. 26.6 ± 2.4% in the control group, p overload and ischemic preconditioning (18.3 ± 1.5% and 18.2 ± 2.0%, respectively, p overload of the left ventricle preconditioned rat myocardium against infarction. Because SPT did not significantly alter MI size reduction, our results did not support a role of adenosine in preconditioning by pressure overload in rats. Copyright © 2013. Published by Elsevier B.V.

  16. Use of a preconditioned Bi-conjugate gradient method for hybrid plasma stability analysis

    International Nuclear Information System (INIS)

    Mikic, Z.; Morse, E.C.

    1985-01-01

    The numerical stability analysis of compact toroidal plasmas using implicit time differencing requires the solution of a set of coupled, 2-dimensional, elliptic partial differential equations for the field quantities at every timestep. When the equations are spatially finite-differenced and written in matrix form, the resulting matrix is large, sparse, complex, non-Hermitian, and indefinite. The use of the preconditioned bi-conjugate gradient method for solving these equations is discussed. The effect of block-diagonal preconditioning and incomplete block-LU preconditionig on the convergence of the method is investigated. For typical matrices arising in our studies, the eigenvalue spectra of the original and preconditioned matrices are calculated as an illustration of the effectiveness of the preconditioning. We show that the preconditioned bi-conjugate gradient method coverages more rapidly than the conjugate gradient method applied to the normal equations, and that it is an effective iterative method for the class of non-Hermitian, indefinite problems of interest

  17. Maximizing your return on people.

    Science.gov (United States)

    Bassi, Laurie; McMurrer, Daniel

    2007-03-01

    Though most traditional HR performance metrics don't predict organizational performance, alternatives simply have not existed--until now. During the past ten years, researchers Laurie Bassi and Daniel McMurrer have worked to develop a system that allows executives to assess human capital management (HCM) and to use those metrics both to predict organizational performance and to guide organizations' investments in people. The new framework is based on a core set of HCM drivers that fall into five major categories: leadership practices, employee engagement, knowledge accessibility, workforce optimization, and organizational learning capacity. By employing rigorously designed surveys to score a company on the range of HCM practices across the five categories, it's possible to benchmark organizational HCM capabilities, identify HCM strengths and weaknesses, and link improvements or back-sliding in specific HCM practices with improvements or shortcomings in organizational performance. The process requires determining a "maturity" score for each practice, based on a scale of 1 (low) to 5 (high). Over time, evolving maturity scores from multiple surveys can reveal progress in each of the HCM practices and help a company decide where to focus improvement efforts that will have a direct impact on performance. The authors draw from their work with American Standard, South Carolina's Beaufort County School District, and a bevy of financial firms to show how improving HCM scores led to increased sales, safety, academic test scores, and stock returns. Bassi and McMurrer urge HR departments to move beyond the usual metrics and begin using HCM measurement tools to gauge how well people are managed and developed throughout the organization. In this new role, according to the authors, HR can take on strategic responsibility and ensure that superior human capital management becomes central to the organization's culture.

  18. Maximally Entangled Multipartite States: A Brief Survey

    International Nuclear Information System (INIS)

    Enríquez, M; Wintrowicz, I; Życzkowski, K

    2016-01-01

    The problem of identifying maximally entangled quantum states of a composite quantum systems is analyzed. We review some states of multipartite systems distinguished with respect to certain measures of quantum entanglement. Numerical results obtained for 4-qubit pure states illustrate the fact that the notion of maximally entangled state depends on the measure used. (paper)

  19. Utility maximization and mode of payment

    NARCIS (Netherlands)

    Koning, R.H.; Ridder, G.; Heijmans, R.D.H.; Pollock, D.S.G.; Satorra, A.

    2000-01-01

    The implications of stochastic utility maximization in a model of choice of payment are examined. Three types of compatibility with utility maximization are distinguished: global compatibility, local compatibility on an interval, and local compatibility on a finite set of points. Keywords:

  20. Corporate Social Responsibility and Profit Maximizing Behaviour

    OpenAIRE

    Becchetti, Leonardo; Giallonardo, Luisa; Tessitore, Maria Elisabetta

    2005-01-01

    We examine the behavior of a profit maximizing monopolist in a horizontal differentiation model in which consumers differ in their degree of social responsibility (SR) and consumers SR is dynamically influenced by habit persistence. The model outlines parametric conditions under which (consumer driven) corporate social responsibility is an optimal choice compatible with profit maximizing behavior.

  1. The Mechanisms of Pharmacological Preconditioning of the Brain and the Comparative Efficacy of the Drugs — Direct- and Indirect-Acting Glycogen Synthase Kinase-3β Inhibitors: Experimental Study

    Directory of Open Access Journals (Sweden)

    V. V. Likhvantsev

    2012-01-01

    Full Text Available Objective: to investigate the activity of sevoflurane, dalargin, and lithium chloride in protecting the rat brain from total ischemia/reperfusion and to define whether the GSK=3^ deposphorylation contributes to the mechanism of pharmacological preconditioning. Materials and methods. Experiments were carried out on 80 male albino rats in which temporary circulatory arrest (CA was simulated by ligating the cardiovascular fascicle for 10 and 20 minutes. The animals were revived by mechanical ventilation external cardiac massage, and the intratracheal injection of adrenaline (epinephrine, Moscow Endocrinology Plant at a dose of 0.1 mg/kg. Animals were divided into 9 groups and sevorane (sevoflurane, Abbott Laboratories, dalargin (Microgen Research-and-Production Association, or lithium chloride (Sigma Chemical Co. were separately given with and without CA. Brain tissue homogenate specimens were obtained from euthanized animals. The concentration of total glycogen synthase kinase-3^ (GSK-3^ was colorimetrically determined using a Hitachi-557 spectrophotometer (Hitachi Ltd., Japan. The content of phosphorylated GSK-3/3 (pGSK-3^ in brain homogenate was estimated by Western blotting. Results. The total level of GSK-3^ in each group was similar (80—90 relative units and remained unchanged throughout each experiment. Twenty-minute ischemia maximally activated GSK-30 through dephosphorylation. Ten-minute ischemia elevated pGSK-3^ levels by more than 5 times as compared to the baseline value revealing the «training» effect. The quantity of pGSK-3^ was unchanged in the ischemia/perfusion group during sevoflurane insufflation and was decreased by 27% during dalargin administration. Conclusion. The experimental model of total ischemia provided evidence that the test drugs had a pharmacological preconditioning effect on brain neurons. According to their increasing effect, the drugs were arranged in the following order: dalargin < sevoflurane < lithium

  2. Inclusive fitness maximization: An axiomatic approach.

    Science.gov (United States)

    Okasha, Samir; Weymark, John A; Bossert, Walter

    2014-06-07

    Kin selection theorists argue that evolution in social contexts will lead organisms to behave as if maximizing their inclusive, as opposed to personal, fitness. The inclusive fitness concept allows biologists to treat organisms as akin to rational agents seeking to maximize a utility function. Here we develop this idea and place it on a firm footing by employing a standard decision-theoretic methodology. We show how the principle of inclusive fitness maximization and a related principle of quasi-inclusive fitness maximization can be derived from axioms on an individual׳s 'as if preferences' (binary choices) for the case in which phenotypic effects are additive. Our results help integrate evolutionary theory and rational choice theory, help draw out the behavioural implications of inclusive fitness maximization, and point to a possible way in which evolution could lead organisms to implement it. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Maximal Entanglement in High Energy Physics

    Directory of Open Access Journals (Sweden)

    Alba Cervera-Lierta, José I. Latorre, Juan Rojo, Luca Rottoli

    2017-11-01

    Full Text Available We analyze how maximal entanglement is generated at the fundamental level in QED by studying correlations between helicity states in tree-level scattering processes at high energy. We demonstrate that two mechanisms for the generation of maximal entanglement are at work: i $s$-channel processes where the virtual photon carries equal overlaps of the helicities of the final state particles, and ii the indistinguishable superposition between $t$- and $u$-channels. We then study whether requiring maximal entanglement constrains the coupling structure of QED and the weak interactions. In the case of photon-electron interactions unconstrained by gauge symmetry, we show how this requirement allows reproducing QED. For $Z$-mediated weak scattering, the maximal entanglement principle leads to non-trivial predictions for the value of the weak mixing angle $\\theta_W$. Our results are a first step towards understanding the connections between maximal entanglement and the fundamental symmetries of high-energy physics.

  4. Hypoxic preconditioning induces neuroprotective stanniocalcin-1 in brain via IL-6 signaling

    DEFF Research Database (Denmark)

    Westberg, Johan A; Serlachius, Martina; Lankila, Petri

    2007-01-01

    BACKGROUND AND PURPOSE: Exposure of animals for a few hours to moderate hypoxia confers relative protection against subsequent ischemic brain damage. This phenomenon, known as hypoxic preconditioning, depends on new RNA and protein synthesis, but its molecular mechanisms are poorly understood...... originally reported expression of mammalian STC-1 in brain neurons and showed that STC-1 guards neurons against hypercalcemic and hypoxic damage. METHODS: We treated neural Paju cells with IL-6 and measured the induction of STC-1 mRNA. In addition, we quantified the effect of hypoxic preconditioning on Stc-1...... mRNA levels in brains of wild-type and IL-6 deficient mice. Furthermore, we monitored the Stc-1 response in brains of wild-type and transgenic mice, overexpressing IL-6 in the astroglia, before and after induced brain injury. RESULTS: Hypoxic preconditioning induced an upregulated expression of Stc...

  5. Nitroglycerine and sodium trioxodinitrate: from the discovery to the preconditioning effect.

    Science.gov (United States)

    Pagliaro, Pasquale; Gattullo, Donatella; Penna, Claudia

    2013-10-01

    The history began in the 19th century with Ascanio Sobrero (1812-1888), the discoverer of glycerol trinitrate (nitroglycerine, NTG), and with Angelo Angeli (1864-1931), the discoverer of sodium trioxodinitrate (Angeli's salt). It is likely that Angeli and Sobrero never met, but their two histories will join each other more than a century later. In fact, it has been discovered that both NTG and Angeli's salt are able to induce a preconditioning effect. As NTG has a long history as an antianginal drug its newly discovered property as a preconditioning agent has also been tested in humans. Angeli's salt properties as a preconditioning and inotropic agent have only been tested in animals so far.

  6. Preconditioned conjugate gradient technique for the analysis of symmetric anisotropic structures

    Science.gov (United States)

    Noor, Ahmed K.; Peters, Jeanne M.

    1987-01-01

    An efficient preconditioned conjugate gradient (PCG) technique and a computational procedure are presented for the analysis of symmetric anisotropic structures. The technique is based on selecting the preconditioning matrix as the orthotropic part of the global stiffness matrix of the structure, with all the nonorthotropic terms set equal to zero. This particular choice of the preconditioning matrix results in reducing the size of the analysis model of the anisotropic structure to that of the corresponding orthotropic structure. The similarities between the proposed PCG technique and a reduction technique previously presented by the authors are identified and exploited to generate from the PCG technique direct measures for the sensitivity of the different response quantities to the nonorthotropic (anisotropic) material coefficients of the structure. The effectiveness of the PCG technique is demonstrated by means of a numerical example of an anisotropic cylindrical panel.

  7. Cerebellar cytokine expression in a rat model for fetal asphyctic preconditioning and perinatal asphyxia

    DEFF Research Database (Denmark)

    Vlassaks, Evi; Brudek, Tomasz; Pakkenberg, Bente

    2014-01-01

    the effects of perinatal asphyxia and fetal asphyctic preconditioning on the inflammatory cytokine response in the cerebellum. Fetal asphyxia was induced at embryonic day 17 by clamping the uterine vasculature for 30 min. At term birth, global perinatal asphyxia was induced by placing the uterine horns...... was decreased 96 h postfetal asphyxia. When applied as preconditioning stimulus, fetal asphyxia attenuates the cerebellar cytokine response. These results indicate that sublethal fetal asphyxia may protect the cerebellum from perinatal asphyxia-induced damage via inhibition of inflammation.......Asphyctic brain injury is a major cause of neuronal inflammation in the perinatal period. Fetal asphyctic preconditioning has been shown to modulate the cerebral inflammatory cytokine response, hereby protecting the brain against asphyctic injury at birth. This study was designated to examine...

  8. Analysis of a Lipid/Polymer Membrane for Bitterness Sensing with a Preconditioning Process

    Directory of Open Access Journals (Sweden)

    Rui Yatabe

    2015-09-01

    Full Text Available It is possible to evaluate the taste of foods or medicines using a taste sensor. The taste sensor converts information on taste into an electrical signal using several lipid/polymer membranes. A lipid/polymer membrane for bitterness sensing can evaluate aftertaste after immersion in monosodium glutamate (MSG, which is called “preconditioning”. However, we have not yet analyzed the change in the surface structure of the membrane as a result of preconditioning. Thus, we analyzed the change in the surface by performing contact angle and surface zeta potential measurements, Fourier transform infrared spectroscopy (FTIR, X-ray photon spectroscopy (XPS and gas cluster ion beam time-of-flight secondary ion mass spectrometry (GCIB-TOF-SIMS. After preconditioning, the concentrations of MSG and tetradodecylammonium bromide (TDAB, contained in the lipid membrane were found to be higher in the surface region than in the bulk region. The effect of preconditioning was revealed by the above analysis methods.

  9. Hypoxia precondition promotes adipose-derived mesenchymal stem cells based repair of diabetic erectile dysfunction via augmenting angiogenesis and neuroprotection.

    Directory of Open Access Journals (Sweden)

    XiYou Wang

    Full Text Available The aim of the present study was to examine whether hypoxia preconditioning could improve therapeutic effects of adipose derived mesenchymal stem cells (AMSCs for diabetes induced erectile dysfunction (DED. AMSCs were pretreated with normoxia (20% O2, N-AMSCs or sub-lethal hypoxia (1% O2, H-AMSCs. The hypoxia exposure up-regulated the expression of several angiogenesis and neuroprotection related cytokines in AMSCs, including vascular endothelial growth factor (VEGF and its receptor FIK-1, angiotensin (Ang-1, basic fibroblast growth factor (bFGF, brain-derived neurotrophic factor (BDNF, glial cell-derived neurotrophic factor (GDNF, stromal derived factor-1 (SDF-1 and its CXC chemokine receptor 4 (CXCR4. DED rats were induced via intraperitoneal injection of streptozotocin (60 mg/kg and were randomly divided into three groups-Saline group: intracavernous injection with phosphate buffer saline; N-AMSCs group: N-AMSCs injection; H-AMSCs group: H-AMSCs injection. Ten rats without any treatment were used as normal control. Four weeks after injection, the mean arterial pressure (MAP and intracavernosal pressure (ICP were measured. The contents of endothelial, smooth muscle, dorsal nerve in cavernoursal tissue were assessed. Compared with N-AMSCs and saline, intracavernosum injection of H-AMSCs significantly raised ICP and ICP/MAP (p<0.05. Immunofluorescent staining analysis demonstrated that improved erectile function by MSCs was significantly associated with increased expression of endothelial markers (CD31 and vWF (p<0.01 and smooth muscle markers (α-SMA (p<0.01. Meanwhile, the expression of nNOS was also significantly higher in rats receiving H-AMSCs injection than those receiving N-AMSCs or saline injection. The results suggested that hypoxic preconditioning of MSCs was an effective approach to enhance their therapeutic effect for DED, which may be due to their augmented angiogenesis and neuroprotection.

  10. Evaluation of anti-hyperglycemic effect of Actinidia kolomikta (Maxim. etRur.) Maxim. root extract.

    Science.gov (United States)

    Hu, Xuansheng; Cheng, Delin; Wang, Linbo; Li, Shuhong; Wang, Yuepeng; Li, Kejuan; Yang, Yingnan; Zhang, Zhenya

    2015-05-01

    This study aimed to evaluate the anti-hyperglycemic effect of ethanol extract from Actinidia kolomikta (Maxim. etRur.) Maxim. root (AKE).An in vitro evaluation was performed by using rat intestinal α-glucosidase (maltase and sucrase), the key enzymes linked with type 2 diabetes. And an in vivo evaluation was also performed by loading maltose, sucrose, glucose to normal rats. As a result, AKE showed concentration-dependent inhibition effects on rat intestinal maltase and rat intestinal sucrase with IC(50) values of 1.83 and 1.03mg/mL, respectively. In normal rats, after loaded with maltose, sucrose and glucose, administration of AKE significantly reduced postprandial hyperglycemia, which is similar to acarbose used as an anti-diabetic drug. High contents of total phenolics (80.49 ± 0.05mg GAE/g extract) and total flavonoids (430.69 ± 0.91mg RE/g extract) were detected in AKE. In conclusion, AKE possessed anti-hyperglycemic effects and the possible mechanisms were associated with its inhibition on α-glucosidase and the improvement on insulin release and/or insulin sensitivity as well. The anti-hyperglycemic activity possessed by AKE maybe attributable to its high contents of phenolic and flavonoid compounds.

  11. Optimal topologies for maximizing network transmission capacity

    Science.gov (United States)

    Chen, Zhenhao; Wu, Jiajing; Rong, Zhihai; Tse, Chi K.

    2018-04-01

    It has been widely demonstrated that the structure of a network is a major factor that affects its traffic dynamics. In this work, we try to identify the optimal topologies for maximizing the network transmission capacity, as well as to build a clear relationship between structural features of a network and the transmission performance in terms of traffic delivery. We propose an approach for designing optimal network topologies against traffic congestion by link rewiring and apply them on the Barabási-Albert scale-free, static scale-free and Internet Autonomous System-level networks. Furthermore, we analyze the optimized networks using complex network parameters that characterize the structure of networks, and our simulation results suggest that an optimal network for traffic transmission is more likely to have a core-periphery structure. However, assortative mixing and the rich-club phenomenon may have negative impacts on network performance. Based on the observations of the optimized networks, we propose an efficient method to improve the transmission capacity of large-scale networks.

  12. The mitochondria-targeted antioxidants and remote kidney preconditioning ameliorate brain damage through kidney-to-brain cross-talk.

    Directory of Open Access Journals (Sweden)

    Denis N Silachev

    Full Text Available BACKGROUND: Many ischemia-induced neurological pathologies including stroke are associated with high oxidative stress. Mitochondria-targeted antioxidants could rescue the ischemic organ by providing specific delivery of antioxidant molecules to the mitochondrion, which potentially suffers from oxidative stress more than non-mitochondrial cellular compartments. Besides direct antioxidative activity, these compounds are believed to activate numerous protective pathways. Endogenous anti-ischemic defense may involve the very powerful neuroprotective agent erythropoietin, which is mainly produced by the kidney in a redox-dependent manner, indicating an important role of the kidney in regulation of brain ischemic damage. The goal of this study is to track the relations between the kidney and the brain in terms of the amplification of defense mechanisms during SkQR1 treatment and remote renal preconditioning and provide evidence that the kidney can generate signals inducing a tolerance to oxidative stress-associated brain pathologies. METHODOLOGY/PRINCIPAL FINDINGS: We used the cationic plastoquinone derivative, SkQR1, as a mitochondria-targeted antioxidant to alleviate the deleterious consequences of stroke. A single injection of SkQR1 before cerebral ischemia in a dose-dependent manner reduces infarction and improves functional recovery. Concomitantly, an increase in the levels of erythropoietin in urine and phosphorylated glycogen synthase kinase-3β (GSK-3β in the brain was detected 24 h after SkQR1 injection. However, protective effects of SkQR1 were not observed in rats with bilateral nephrectomy and in those treated with the nephrotoxic antibiotic gentamicin, indicating the protective role of humoral factor(s which are released from functional kidneys. Renal preconditioning also induced brain protection in rats accompanied by an increased erythropoietin level in urine and kidney tissue and P-GSK-3β in brain. Co-cultivation of SkQR1-treated

  13. The mitochondria-targeted antioxidants and remote kidney preconditioning ameliorate brain damage through kidney-to-brain cross-talk.

    Science.gov (United States)

    Silachev, Denis N; Isaev, Nikolay K; Pevzner, Irina B; Zorova, Ljubava D; Stelmashook, Elena V; Novikova, Svetlana V; Plotnikov, Egor Y; Skulachev, Vladimir P; Zorov, Dmitry B

    2012-01-01

    Many ischemia-induced neurological pathologies including stroke are associated with high oxidative stress. Mitochondria-targeted antioxidants could rescue the ischemic organ by providing specific delivery of antioxidant molecules to the mitochondrion, which potentially suffers from oxidative stress more than non-mitochondrial cellular compartments. Besides direct antioxidative activity, these compounds are believed to activate numerous protective pathways. Endogenous anti-ischemic defense may involve the very powerful neuroprotective agent erythropoietin, which is mainly produced by the kidney in a redox-dependent manner, indicating an important role of the kidney in regulation of brain ischemic damage. The goal of this study is to track the relations between the kidney and the brain in terms of the amplification of defense mechanisms during SkQR1 treatment and remote renal preconditioning and provide evidence that the kidney can generate signals inducing a tolerance to oxidative stress-associated brain pathologies. We used the cationic plastoquinone derivative, SkQR1, as a mitochondria-targeted antioxidant to alleviate the deleterious consequences of stroke. A single injection of SkQR1 before cerebral ischemia in a dose-dependent manner reduces infarction and improves functional recovery. Concomitantly, an increase in the levels of erythropoietin in urine and phosphorylated glycogen synthase kinase-3β (GSK-3β) in the brain was detected 24 h after SkQR1 injection. However, protective effects of SkQR1 were not observed in rats with bilateral nephrectomy and in those treated with the nephrotoxic antibiotic gentamicin, indicating the protective role of humoral factor(s) which are released from functional kidneys. Renal preconditioning also induced brain protection in rats accompanied by an increased erythropoietin level in urine and kidney tissue and P-GSK-3β in brain. Co-cultivation of SkQR1-treated kidney cells with cortical neurons resulted in enchanced

  14. High-Order Calderón Preconditioned Time Domain Integral Equation Solvers

    KAUST Repository

    Valdes, Felipe

    2013-05-01

    Two high-order accurate Calderón preconditioned time domain electric field integral equation (TDEFIE) solvers are presented. In contrast to existing Calderón preconditioned time domain solvers, the proposed preconditioner allows for high-order surface representations and current expansions by using a novel set of fully-localized high-order div-and quasi curl-conforming (DQCC) basis functions. Numerical results demonstrate that the linear systems of equations obtained using the proposed basis functions converge rapidly, regardless of the mesh density and of the order of the current expansion. © 1963-2012 IEEE.

  15. PBMC: Pre-conditioned Backward Monte Carlo code for radiative transport in planetary atmospheres

    Science.gov (United States)

    García Muñoz, A.; Mills, F. P.

    2017-08-01

    PBMC (Pre-Conditioned Backward Monte Carlo) solves the vector Radiative Transport Equation (vRTE) and can be applied to planetary atmospheres irradiated from above. The code builds the solution by simulating the photon trajectories from the detector towards the radiation source, i.e. in the reverse order of the actual photon displacements. In accounting for the polarization in the sampling of photon propagation directions and pre-conditioning the scattering matrix with information from the scattering matrices of prior (in the BMC integration order) photon collisions, PBMC avoids the unstable and biased solutions of classical BMC algorithms for conservative, optically-thick, strongly-polarizing media such as Rayleigh atmospheres.

  16. High-Order Calderón Preconditioned Time Domain Integral Equation Solvers

    KAUST Repository

    Valdes, Felipe; Ghaffari-Miab, Mohsen; Andriulli, Francesco P.; Cools, Kristof; Michielssen,

    2013-01-01

    Two high-order accurate Calderón preconditioned time domain electric field integral equation (TDEFIE) solvers are presented. In contrast to existing Calderón preconditioned time domain solvers, the proposed preconditioner allows for high-order surface representations and current expansions by using a novel set of fully-localized high-order div-and quasi curl-conforming (DQCC) basis functions. Numerical results demonstrate that the linear systems of equations obtained using the proposed basis functions converge rapidly, regardless of the mesh density and of the order of the current expansion. © 1963-2012 IEEE.

  17. Preconditioned dynamic mode decomposition and mode selection algorithms for large datasets using incremental proper orthogonal decomposition

    Science.gov (United States)

    Ohmichi, Yuya

    2017-07-01

    In this letter, we propose a simple and efficient framework of dynamic mode decomposition (DMD) and mode selection for large datasets. The proposed framework explicitly introduces a preconditioning step using an incremental proper orthogonal decomposition (POD) to DMD and mode selection algorithms. By performing the preconditioning step, the DMD and mode selection can be performed with low memory consumption and therefore can be applied to large datasets. Additionally, we propose a simple mode selection algorithm based on a greedy method. The proposed framework is applied to the analysis of three-dimensional flow around a circular cylinder.

  18. Impact of pre-conditioning on the qualification of safety-related equipment

    International Nuclear Information System (INIS)

    Isgro, J.R.

    1982-01-01

    This paper shares some recent experiences on the effects of preconditioning on the qualification of safety-related equipment not located in a harsh environment. Environmental and seismic qualification testing programs were conducted following the guidelines of IEEE 323-1974, IEEE 344-1975 and appropriate IEEE daughter standards, where available. The examples that follow will illustrate the degree of pre-conditioning of safety-related equipment qualified to the requirements of IEEE-323-1974, and its effect on the outcome of the qualification program

  19. Preconditions for Emergence of Lithuanian Clusters: from Informal Cooperation to Its Legitimation

    Directory of Open Access Journals (Sweden)

    Grumadaitė Kristina

    2017-06-01

    Full Text Available This paper reveals preconditions for the emergence of clusters as self-organisation based industrial systems in a context, in which cooperation traditions are insufficiently developed. These preconditions reflect the principles of the emergence of self-organising complex adaptive systems that are analysed in the complexity theory. Those principles are based on the initiation of non-equilibrium and its purposeful direction into the creation of a new order. This paper highlights the main external and internal tensions that influence informal or formal clustering of enterprises, while various change agents perform different roles making self-organising processes to occur.

  20. PRECONDITIONED BI-CONJUGATE GRADIENT METHOD FOR RADIATIVE TRANSFER IN SPHERICAL MEDIA

    International Nuclear Information System (INIS)

    Anusha, L. S.; Nagendra, K. N.; Paletou, F.; Leger, L.

    2009-01-01

    A robust numerical method called the Preconditioned Bi-Conjugate Gradient (Pre-BiCG) method is proposed for the solution of the radiative transfer equation in spherical geometry. A variant of this method called Stabilized Preconditioned Bi-Conjugate Gradient (Pre-BiCG-STAB) is also presented. These are iterative methods based on the construction of a set of bi-orthogonal vectors. The application of the Pre-BiCG method in some benchmark tests shows that the method is quite versatile, and can handle difficult problems that may arise in astrophysical radiative transfer theory.

  1. Effects of nitrous oxide on the rat heart in vivo: another inhalational anesthetic that preconditions the heart?

    NARCIS (Netherlands)

    Weber, Nina C.; Toma, Octavian; Awan, Saqib; Frässdorf, Jan; Preckel, Benedikt; Schlack, Wolfgang

    2005-01-01

    BACKGROUND: For nitrous oxide, a preconditioning effect on the heart has yet not been investigated. This is important because nitrous oxide is commonly used in combination with volatile anesthetics, which are known to precondition the heart. The authors aimed to clarify (1) whether nitrous oxide

  2. Comparison of the mass preconditioned HMC and the DD-HMC algorithm for two-flavour QCD

    CERN Document Server

    Marinkovic, Marina

    2010-01-01

    Mass preconditioned HMC and DD-HMC are among the most popular algorithms to simulate Wilson fermions. We present a comparison of the performance of the two algorithms for realistic quark masses and lattice sizes. In particular, we use the locally deflated solver of the DD-HMC environment also for the mass preconditioned simulations.

  3. The effectiveness of a preconditioning programme on preventing running-related injuries in novice runners : a randomised controlled trial

    NARCIS (Netherlands)

    Bredeweg, Steef W.; Zijlstra, Sjouke; Bessem, Bram; Buist, Ida

    Objectives There is no consensus on the aetiology and prevention of running-related injuries in runners. Preconditioning studies among different athlete populations show positive effects on the incidence of sports injuries. Hypothesis A 4-week preconditioning programme in novice runners will reduce

  4. Light Microscopy at Maximal Precision

    Directory of Open Access Journals (Sweden)

    Matthew Bierbaum

    2017-10-01

    Full Text Available Microscopy is the workhorse of the physical and life sciences, producing crisp images of everything from atoms to cells well beyond the capabilities of the human eye. However, the analysis of these images is frequently little more accurate than manual marking. Here, we revolutionize the analysis of microscopy images, extracting all the useful information theoretically contained in a complex microscope image. Using a generic, methodological approach, we extract the information by fitting experimental images with a detailed optical model of the microscope, a method we call parameter extraction from reconstructing images (PERI. As a proof of principle, we demonstrate this approach with a confocal image of colloidal spheres, improving measurements of particle positions and radii by 10–100 times over current methods and attaining the maximum possible accuracy. With this unprecedented accuracy, we measure nanometer-scale colloidal interactions in dense suspensions solely with light microscopy, a previously impossible feat. Our approach is generic and applicable to imaging methods from brightfield to electron microscopy, where we expect accuracies of 1 nm and 0.1 pm, respectively.

  5. Light Microscopy at Maximal Precision

    Science.gov (United States)

    Bierbaum, Matthew; Leahy, Brian D.; Alemi, Alexander A.; Cohen, Itai; Sethna, James P.

    2017-10-01

    Microscopy is the workhorse of the physical and life sciences, producing crisp images of everything from atoms to cells well beyond the capabilities of the human eye. However, the analysis of these images is frequently little more accurate than manual marking. Here, we revolutionize the analysis of microscopy images, extracting all the useful information theoretically contained in a complex microscope image. Using a generic, methodological approach, we extract the information by fitting experimental images with a detailed optical model of the microscope, a method we call parameter extraction from reconstructing images (PERI). As a proof of principle, we demonstrate this approach with a confocal image of colloidal spheres, improving measurements of particle positions and radii by 10-100 times over current methods and attaining the maximum possible accuracy. With this unprecedented accuracy, we measure nanometer-scale colloidal interactions in dense suspensions solely with light microscopy, a previously impossible feat. Our approach is generic and applicable to imaging methods from brightfield to electron microscopy, where we expect accuracies of 1 nm and 0.1 pm, respectively.

  6. Preconditioning of adipose tissue-derived mesenchymal stem cells with deferoxamine increases the production of pro-angiogenic, neuroprotective and anti-inflammatory factors: Potential application in the treatment of diabetic neuropathy.

    Science.gov (United States)

    Oses, Carolina; Olivares, Belén; Ezquer, Marcelo; Acosta, Cristian; Bosch, Paul; Donoso, Macarena; Léniz, Patricio; Ezquer, Fernando

    2017-01-01

    evaluated in an in vitro model of DN. Altogether, our findings suggest that DFX preconditioning of AD-MSCs improves their therapeutic potential and should be considered as a potential strategy for the generation of new alternatives for DN treatment.

  7. Bipartite Bell Inequality and Maximal Violation

    International Nuclear Information System (INIS)

    Li Ming; Fei Shaoming; Li-Jost Xian-Qing

    2011-01-01

    We present new bell inequalities for arbitrary dimensional bipartite quantum systems. The maximal violation of the inequalities is computed. The Bell inequality is capable of detecting quantum entanglement of both pure and mixed quantum states more effectively. (general)

  8. HEALTH INSURANCE: CONTRIBUTIONS AND REIMBURSEMENT MAXIMAL

    CERN Document Server

    HR Division

    2000-01-01

    Affected by both the salary adjustment index on 1.1.2000 and the evolution of the staff members and fellows population, the average reference salary, which is used as an index for fixed contributions and reimbursement maximal, has changed significantly. An adjustment of the amounts of the reimbursement maximal and the fixed contributions is therefore necessary, as from 1 January 2000.Reimbursement maximalThe revised reimbursement maximal will appear on the leaflet summarising the benefits for the year 2000, which will soon be available from the divisional secretariats and from the AUSTRIA office at CERN.Fixed contributionsThe fixed contributions, applicable to some categories of voluntarily insured persons, are set as follows (amounts in CHF for monthly contributions):voluntarily insured member of the personnel, with complete coverage:815,- (was 803,- in 1999)voluntarily insured member of the personnel, with reduced coverage:407,- (was 402,- in 1999)voluntarily insured no longer dependent child:326,- (was 321...

  9. Maximal Inequalities for Dependent Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jorgensen, Jorgen

    2016-01-01

    Maximal inequalities play a crucial role in many probabilistic limit theorem; for instance, the law of large numbers, the law of the iterated logarithm, the martingale limit theorem and the central limit theorem. Let X-1, X-2,... be random variables with partial sums S-k = X-1 + ... + X-k. Then a......Maximal inequalities play a crucial role in many probabilistic limit theorem; for instance, the law of large numbers, the law of the iterated logarithm, the martingale limit theorem and the central limit theorem. Let X-1, X-2,... be random variables with partial sums S-k = X-1 + ... + X......-k. Then a maximal inequality gives conditions ensuring that the maximal partial sum M-n = max(1) (...

  10. Maximizing Function through Intelligent Robot Actuator Control

    Data.gov (United States)

    National Aeronautics and Space Administration — Maximizing Function through Intelligent Robot Actuator Control Successful missions to Mars and beyond will only be possible with the support of high-performance...

  11. An ethical justification of profit maximization

    DEFF Research Database (Denmark)

    Koch, Carsten Allan

    2010-01-01

    In much of the literature on business ethics and corporate social responsibility, it is more or less taken for granted that attempts to maximize profits are inherently unethical. The purpose of this paper is to investigate whether an ethical argument can be given in support of profit maximizing...... behaviour. It is argued that some form of consequential ethics must be applied, and that both profit seeking and profit maximization can be defended from a rule-consequential point of view. It is noted, however, that the result does not apply unconditionally, but requires that certain form of profit (and...... utility) maximizing actions are ruled out, e.g., by behavioural norms or formal institutions....

  12. A definition of maximal CP-violation

    International Nuclear Information System (INIS)

    Roos, M.

    1985-01-01

    The unitary matrix of quark flavour mixing is parametrized in a general way, permitting a mathematically natural definition of maximal CP violation. Present data turn out to violate this definition by 2-3 standard deviations. (orig.)

  13. A cosmological problem for maximally symmetric supergravity

    International Nuclear Information System (INIS)

    German, G.; Ross, G.G.

    1986-01-01

    Under very general considerations it is shown that inflationary models of the universe based on maximally symmetric supergravity with flat potentials are unable to resolve the cosmological energy density (Polonyi) problem. (orig.)

  14. Insulin resistance and maximal oxygen uptake

    DEFF Research Database (Denmark)

    Seibaek, Marie; Vestergaard, Henrik; Burchardt, Hans

    2003-01-01

    BACKGROUND: Type 2 diabetes, coronary atherosclerosis, and physical fitness all correlate with insulin resistance, but the relative importance of each component is unknown. HYPOTHESIS: This study was undertaken to determine the relationship between insulin resistance, maximal oxygen uptake......, and the presence of either diabetes or ischemic heart disease. METHODS: The study population comprised 33 patients with and without diabetes and ischemic heart disease. Insulin resistance was measured by a hyperinsulinemic euglycemic clamp; maximal oxygen uptake was measured during a bicycle exercise test. RESULTS......: There was a strong correlation between maximal oxygen uptake and insulin-stimulated glucose uptake (r = 0.7, p = 0.001), and maximal oxygen uptake was the only factor of importance for determining insulin sensitivity in a model, which also included the presence of diabetes and ischemic heart disease. CONCLUSION...

  15. Maximal supergravities and the E10 model

    International Nuclear Information System (INIS)

    Kleinschmidt, Axel; Nicolai, Hermann

    2006-01-01

    The maximal rank hyperbolic Kac-Moody algebra e 10 has been conjectured to play a prominent role in the unification of duality symmetries in string and M theory. We review some recent developments supporting this conjecture

  16. The role of K –ATP channel in the preconditioning effect of magnesium in the rat isolated heart

    Directory of Open Access Journals (Sweden)

    Bazargan M.

    2007-05-01

    Full Text Available There is growing interest for beneficial effect of Mg in the cardiovascular disorders. A number of cardiovascular disorders including myocardial infarction, arrhythmias and congestive heart failure have been associated with low extracellular or intracellular concentrations of Mg. The aim of present study was to investigate the preconditioning effects of magnesium (Mg on cardiac function and infarct size in the globally ischemic-reperfusion in isolated rat heart. Rat hearts were Langendorff-perfused, subjected to 30 minutes of global ischemia and 90 minutes of reperfusion, and assigned to one of the following treatment groups with 7 hearts in each group: (1 control, (2 ischemic- reperfusion, (IR, (3 ischemic preconditioning, (IPC of 5 minutes of global ischemia - reperfusion before lethal ischemia; or pretreatment with (4 30 µmol/L of Diazoxide (Dia, (5 8 mmol/L magnesium, (6 10 µmol/L glibenclamid (Gli, (7 magnesium and Dia and (8 magnesium and Gli. Infarct size was measured by the triphenyltetrazolium chloride method. Left ventricular function was assessed by left ventricular developed pressure (LVDP, heart rate and coronary flow (CF. Mg limited infarct size (9.76 % vs 44.47% in IR, P< 0.001 as did Dia (10.2 % vs 44.4 % in IR P< 0.001 and IPC (8.69 % vs 44.47% in IR, P< 0.001. The protective effect of magnesium was abolished by Gli. Administration of Mg had an anti-infarct effect in ischemic-reperfusion isolated rat hearts and improved cardiac function. Blockade of K-ATP channel abolished the protective effects of magnesium and suggest that K-ATP channel has an important role in this effects.

  17. Gaussian maximally multipartite-entangled states

    Science.gov (United States)

    Facchi, Paolo; Florio, Giuseppe; Lupo, Cosmo; Mancini, Stefano; Pascazio, Saverio

    2009-12-01

    We study maximally multipartite-entangled states in the context of Gaussian continuous variable quantum systems. By considering multimode Gaussian states with constrained energy, we show that perfect maximally multipartite-entangled states, which exhibit the maximum amount of bipartite entanglement for all bipartitions, only exist for systems containing n=2 or 3 modes. We further numerically investigate the structure of these states and their frustration for n≤7 .

  18. Gaussian maximally multipartite-entangled states

    International Nuclear Information System (INIS)

    Facchi, Paolo; Florio, Giuseppe; Pascazio, Saverio; Lupo, Cosmo; Mancini, Stefano

    2009-01-01

    We study maximally multipartite-entangled states in the context of Gaussian continuous variable quantum systems. By considering multimode Gaussian states with constrained energy, we show that perfect maximally multipartite-entangled states, which exhibit the maximum amount of bipartite entanglement for all bipartitions, only exist for systems containing n=2 or 3 modes. We further numerically investigate the structure of these states and their frustration for n≤7.

  19. Neutrino mass textures with maximal CP violation

    International Nuclear Information System (INIS)

    Aizawa, Ichiro; Kitabayashi, Teruyuki; Yasue, Masaki

    2005-01-01

    We show three types of neutrino mass textures, which give maximal CP violation as well as maximal atmospheric neutrino mixing. These textures are described by six real mass parameters: one specified by two complex flavor neutrino masses and two constrained ones and the others specified by three complex flavor neutrino masses. In each texture, we calculate mixing angles and masses, which are consistent with observed data, as well as Majorana CP phases

  20. Why firms should not always maximize profits

    OpenAIRE

    Kolstad, Ivar

    2006-01-01

    Though corporate social responsibility (CSR) is on the agenda of most major corporations, corporate executives still largely support the view that corporations should maximize the returns to their owners. There are two lines of defence for this position. One is the Friedmanian view that maximizing owner returns is the corporate social responsibility of corporations. The other is a position voiced by many executives, that CSR and profits go together. This paper argues that the first position i...

  1. Maximally Informative Observables and Categorical Perception

    OpenAIRE

    Tsiang, Elaine

    2012-01-01

    We formulate the problem of perception in the framework of information theory, and prove that categorical perception is equivalent to the existence of an observable that has the maximum possible information on the target of perception. We call such an observable maximally informative. Regardless whether categorical perception is real, maximally informative observables can form the basis of a theory of perception. We conclude with the implications of such a theory for the problem of speech per...

  2. High Intensity Interval Training for Maximizing Health Outcomes.

    Science.gov (United States)

    Karlsen, Trine; Aamot, Inger-Lise; Haykowsky, Mark; Rognmo, Øivind

    Regular physical activity and exercise training are important actions to improve cardiorespiratory fitness and maintain health throughout life. There is solid evidence that exercise is an effective preventative strategy against at least 25 medical conditions, including cardiovascular disease, stroke, hypertension, colon and breast cancer, and type 2 diabetes. Traditionally, endurance exercise training (ET) to improve health related outcomes has consisted of low- to moderate ET intensity. However, a growing body of evidence suggests that higher exercise intensities may be superior to moderate intensity for maximizing health outcomes. The primary objective of this review is to discuss how aerobic high-intensity interval training (HIIT) as compared to moderate continuous training may maximize outcomes, and to provide practical advices for successful clinical and home-based HIIT. Copyright © 2017. Published by Elsevier Inc.

  3. Late preconditioning is blocked by racemic ketamine, but not by S(+)-ketamine

    NARCIS (Netherlands)

    Müllenheim, J.; Rulands, R.; Wietschorke, T.; Frässdorf, J.; Preckel, B.; Schlack, W.

    2001-01-01

    Racemic ketamine blocks K(ATP) channels in isolated cells and abolishes short-term cardioprotection against prolonged ischemia. We investigated the effects of racemic ketamine and S(+)-ketamine on ischemic late preconditioning (LPC) in the rabbit heart in vivo. A coronary occluder was chronically

  4. Comparison of preconditioned Krylov subspace iteration methods for PDE-constrained optimization problems

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe; Farouq, S.; Neytcheva, M.

    2017-01-01

    Roč. 74, č. 1 (2017), s. 19-37 ISSN 1017-1398 Institutional support: RVO:68145535 Keywords : PDE-constrained optimization problems * finite elements * iterative solution method s * preconditioning Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 1.241, year: 2016 https://link.springer.com/article/10.1007%2Fs11075-016-0136-5

  5. Discretization error estimates in maximum norm for convergent splittings of matrices with a monotone preconditioning part

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe; Karátson, J.

    2017-01-01

    Roč. 210, January 2017 (2017), s. 155-164 ISSN 0377-0427 Institutional support: RVO:68145535 Keywords : finite difference method * error estimates * matrix splitting * preconditioning Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 1.357, year: 2016 http://www. science direct.com/ science /article/pii/S0377042716301492?via%3Dihub

  6. On the Eigenvalues and Eigenvectors of Block Triangular Preconditioned Block Matrices

    KAUST Repository

    Pestana, Jennifer

    2014-01-01

    Block lower triangular matrices and block upper triangular matrices are popular preconditioners for 2×2 block matrices. In this note we show that a block lower triangular preconditioner gives the same spectrum as a block upper triangular preconditioner and that the eigenvectors of the two preconditioned matrices are related. © 2014 Society for Industrial and Applied Mathematics.

  7. GPU acceleration of preconditioned solvers for ill-conditioned linear systems

    NARCIS (Netherlands)

    Gupta, R.

    2015-01-01

    In this work we study the implementations of deflation and preconditioning techniques for solving ill-conditioned linear systems using iterative methods. Solving such systems can be a time-consuming process because of the jumps in the coefficients due to large difference in material properties. We

  8. Comparison results on preconditioned SOR-type iterative method for Z-matrices linear systems

    Science.gov (United States)

    Wang, Xue-Zhong; Huang, Ting-Zhu; Fu, Ying-Ding

    2007-09-01

    In this paper, we present some comparison theorems on preconditioned iterative method for solving Z-matrices linear systems, Comparison results show that the rate of convergence of the Gauss-Seidel-type method is faster than the rate of convergence of the SOR-type iterative method.

  9. Solving large test-day models by iteration on data and preconditioned conjugate gradient.

    Science.gov (United States)

    Lidauer, M; Strandén, I; Mäntysaari, E A; Pösö, J; Kettunen, A

    1999-12-01

    A preconditioned conjugate gradient method was implemented into an iteration on a program for data estimation of breeding values, and its convergence characteristics were studied. An algorithm was used as a reference in which one fixed effect was solved by Gauss-Seidel method, and other effects were solved by a second-order Jacobi method. Implementation of the preconditioned conjugate gradient required storing four vectors (size equal to number of unknowns in the mixed model equations) in random access memory and reading the data at each round of iteration. The preconditioner comprised diagonal blocks of the coefficient matrix. Comparison of algorithms was based on solutions of mixed model equations obtained by a single-trait animal model and a single-trait, random regression test-day model. Data sets for both models used milk yield records of primiparous Finnish dairy cows. Animal model data comprised 665,629 lactation milk yields and random regression test-day model data of 6,732,765 test-day milk yields. Both models included pedigree information of 1,099,622 animals. The animal model ¿random regression test-day model¿ required 122 ¿305¿ rounds of iteration to converge with the reference algorithm, but only 88 ¿149¿ were required with the preconditioned conjugate gradient. To solve the random regression test-day model with the preconditioned conjugate gradient required 237 megabytes of random access memory and took 14% of the computation time needed by the reference algorithm.

  10. Comparison of preconditioned Krylov subspace iteration methods for PDE-constrained optimization problems

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe; Farouq, S.; Neytcheva, M.

    2017-01-01

    Roč. 74, č. 1 (2017), s. 19-37 ISSN 1017-1398 Institutional support: RVO:68145535 Keywords : PDE-constrained optimization problems * finite elements * iterative solution methods * preconditioning Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 1.241, year: 2016 https://link.springer.com/article/10.1007%2Fs11075-016-0136-5

  11. Cognitive Preconditions of Early Reading and Spelling: A Latent-Variable Approach with Longitudinal Data

    Science.gov (United States)

    Preßler, Anna-Lena; Könen, Tanja; Hasselhorn, Marcus; Krajewski, Kristin

    2014-01-01

    The aim of the present study was to empirically disentangle the interdependencies of the impact of nonverbal intelligence, working memory capacities, and phonological processing skills on early reading decoding and spelling within a latent variable approach. In a sample of 127 children, these cognitive preconditions were assessed before the onset…

  12. Absence of robust ischemic preconditioning by five 1-minute total umbilical cord occlusions in fetal sheep.

    NARCIS (Netherlands)

    Lotgering, F.K.; Bishai, J.M.; Struijk, P.C.; Blood, A.B.; Hunter, C.J.; Oberg, K.C.; Power, G.G.; Longo, L.D.

    2004-01-01

    OBJECTIVE: To determine to what extent a series of five 1-minute total umbilical cord occlusions, intended to induce ischemic preconditioning (IP), affects the physiologic responses to a 10-minute total umbilical cord occlusion (damaging insult [DI]) 1 hour later and provides cardio- and

  13. Preconditioned finite-difference frequency-domain for modelling periodic dielectric structures - comparisons with FDTD

    NARCIS (Netherlands)

    Chabory, A.; Hon, de B.P.; Schilders, W.H.A.; Tijhuis, A.G.

    2008-01-01

    Finite-difference techniques are very popular and versatile numerical tools in computational electromagnetics. In this paper, we propose a preconditioned finite-difference frequency-domain method (FDFD) to model periodic structures in 2D and 3D. The preconditioner follows from a modal decoupling

  14. Preconditioned finite-difference frequency-domain for modelling periodic dielectric structures : comparisons with FDTD

    NARCIS (Netherlands)

    Chabory, A.; Hon, de B.P.; Schilders, W.H.A.; Tijhuis, A.G.

    2008-01-01

    Finite-difference techniques are very popular and versatile numerical tools in computational electromagnetics. In this paper, we propose a preconditioned finite-difference frequency-domain method (FDFD) to model periodic structures in 2D and 3D. The preconditioner follows from a modal decoupling

  15. Impact of remote ischemic preconditioning on wound healing in small bowel anastomoses

    Science.gov (United States)

    Holzner, Philipp Anton; Kulemann, Birte; Kuesters, Simon; Timme, Sylvia; Hoeppner, Jens; Hopt, Ulrich Theodor; Marjanovic, Goran

    2011-01-01

    AIM: To investigate the influence of remote ischemic preconditioning (RIPC) on anastomotic integrity. METHODS: Sixty male Wistar rats were randomized to six groups. The control group (n = 10) had an end-to-end ileal anastomosis without RIPC. The preconditioned groups (n = 34) varied in time of ischemia and time of reperfusion. One group received the amino acid L-arginine before constructing the anastomosis (n = 9). On postoperative day 4, the rats were re-laparotomized, and bursting pressure, hydroxyproline concentration, intra-abdominal adhesions, and a histological score concerning the mucosal ischemic injury were collected. The data are given as median (range). RESULTS: On postoperative day 4, median bursting pressure was 124 mmHg (60-146 mmHg) in the control group. The experimental groups did not show a statistically significant difference (P > 0.05). Regarding the hydroxyproline concentration, we did not find any significant variation in the experimental groups. We detected significantly less mucosal injury in the RIPC groups. Furthermore, we assessed more extensive intra-abdominal adhesions in the preconditioned groups than in the control group. CONCLUSION: RIPC directly before performing small bowel anastomosis does not affect anastomotic stability in the early period, as seen in ischemic preconditioning. PMID:21455330

  16. Hypoxic preconditioning protects photoreceptors against light damage independently of hypoxia inducible transcription factors in rods.

    Science.gov (United States)

    Kast, Brigitte; Schori, Christian; Grimm, Christian

    2016-05-01

    Hypoxic preconditioning protects photoreceptors against light-induced degeneration preserving retinal morphology and function. Although hypoxia inducible transcription factors 1 and 2 (HIF1, HIF2) are the main regulators of the hypoxic response, photoreceptor protection does not depend on HIF1 in rods. Here we used rod-specific Hif2a single and Hif1a;Hif2a double knockout mice to investigate the potential involvement of HIF2 in rods for protection after hypoxic preconditioning. To identify potential HIF2 target genes in rods we determined the retinal transcriptome of hypoxic control and rod-specific Hif2a knockouts by RNA sequencing. We show that rods do not need HIF2 for hypoxia-induced increased survival after light exposure. The transcriptomic analysis revealed a number of genes that are potentially regulated by HIF2 in rods; among those were Htra1, Timp3 and Hmox1, candidates that are interesting due to their connection to human degenerative diseases of the retina. We conclude that neither HIF1 nor HIF2 are required in photoreceptors for protection by hypoxic preconditioning. We hypothesize that HIF transcription factors may be needed in other cells to produce protective factors acting in a paracrine fashion on photoreceptor cells. Alternatively, hypoxic preconditioning induces a rod-intrinsic response that is independent of HIF transcription factors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. An M-step preconditioned conjugate gradient method for parallel computation

    Science.gov (United States)

    Adams, L.

    1983-01-01

    This paper describes a preconditioned conjugate gradient method that can be effectively implemented on both vector machines and parallel arrays to solve sparse symmetric and positive definite systems of linear equations. The implementation on the CYBER 203/205 and on the Finite Element Machine is discussed and results obtained using the method on these machines are given.

  18. On the use of rigid body modes in the deflated preconditioned conjugate gradient method

    NARCIS (Netherlands)

    Jönsthövel, T.B.; Van Gijzen, M.B.; Vuik, C.; Scarpas, A.

    2011-01-01

    Large discontinuities in material properties, such as encountered in composite materials, lead to ill-conditioned systems of linear equations. These discontinuities give rise to small eigenvalues that may negatively affect the convergence of iterative solution methods such as the Preconditioned

  19. Using Chebyshev polynomials and approximate inverse triangular factorizations for preconditioning the conjugate gradient method

    Science.gov (United States)

    Kaporin, I. E.

    2012-02-01

    In order to precondition a sparse symmetric positive definite matrix, its approximate inverse is examined, which is represented as the product of two sparse mutually adjoint triangular matrices. In this way, the solution of the corresponding system of linear algebraic equations (SLAE) by applying the preconditioned conjugate gradient method (CGM) is reduced to performing only elementary vector operations and calculating sparse matrix-vector products. A method for constructing the above preconditioner is described and analyzed. The triangular factor has a fixed sparsity pattern and is optimal in the sense that the preconditioned matrix has a minimum K-condition number. The use of polynomial preconditioning based on Chebyshev polynomials makes it possible to considerably reduce the amount of scalar product operations (at the cost of an insignificant increase in the total number of arithmetic operations). The possibility of an efficient massively parallel implementation of the resulting method for solving SLAEs is discussed. For a sequential version of this method, the results obtained by solving 56 test problems from the Florida sparse matrix collection (which are large-scale and ill-conditioned) are presented. These results show that the method is highly reliable and has low computational costs.

  20. How preconditioning affects the measurement of poro-viscoelastic mechanical properties in biological tissues

    NARCIS (Netherlands)

    Hosseini, S.M.; Wilson, W.; Ito, K.; Donkelaar, van C.C.

    2014-01-01

    It is known that initial loading curves of soft biological tissues are substantially different from subsequent loadings. The later loading curves are generally used for assessing the mechanical properties of a tissue, and the first loading cycles, referred to as preconditioning, are omitted.

  1. Delphi-research for exploring essential components and preconditions for case management for people with dementia.

    NARCIS (Netherlands)

    Verkade, P.J.; Meijel, B. van; Brink, C.; Os-Medendorp, H. van; Koekkoek, B.; Francke, A.L.

    2010-01-01

    Background: Case management programmes for home-dwelling people with dementia and their informal carers exist in multiple forms and shapes. The aim of this research was to identify the essential components of case management for people with dementia as well as the preconditions for an effective

  2. Implementation of a direct procedure for critical point computations using preconditioned iterative solvers

    Czech Academy of Sciences Publication Activity Database

    Kouhia, R.; Tůma, Miroslav; Mäkinen, J.; Fedoroff, A.; Marjamäki, H.

    108-109, October (2012), s. 110-117 ISSN 0045-7949 R&D Projects: GA ČR(CZ) GAP108/11/0853 Institutional research plan: CEZ:AV0Z10300504 Keywords : non-linear eigenvalue problem * equilibrium equations * critical points * preconditioned iterations Subject RIV: BA - General Mathematics Impact factor: 1.509, year: 2012

  3. Discretization error estimates in maximum norm for convergent splittings of matrices with a monotone preconditioning part

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe; Karátson, J.

    2017-01-01

    Roč. 210, January 2017 (2017), s. 155-164 ISSN 0377-0427 Institutional support: RVO:68145535 Keywords : finite difference method * error estimates * matrix splitting * preconditioning Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 1.357, year: 2016 http://www.sciencedirect.com/science/article/pii/S0377042716301492?via%3Dihub

  4. On preconditioning techniques for dense linear systems arising from singular boundary integral equations

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ke [Univ. of Liverpool (United Kingdom)

    1996-12-31

    We study various preconditioning techniques for the iterative solution of boundary integral equations, and aim to provide a theory for a class of sparse preconditioners. Two related ideas are explored here: singularity separation and inverse approximation. Our preliminary conclusion is that singularity separation based preconditioners perform better than approximate inverse based while it is desirable to have both features.

  5. Shareholder, stakeholder-owner or broad stakeholder maximization

    OpenAIRE

    Mygind, Niels

    2004-01-01

    With reference to the discussion about shareholder versus stakeholder maximization it is argued that the normal type of maximization is in fact stakeholder-owner maxi-mization. This means maximization of the sum of the value of the shares and stake-holder benefits belonging to the dominating stakeholder-owner. Maximization of shareholder value is a special case of owner-maximization, and only under quite re-strictive assumptions shareholder maximization is larger or equal to stakeholder-owner...

  6. Ischemic preconditioning provides both acute and delayed protection against renal ischemia and reperfusion injury in mice.

    Science.gov (United States)

    Joo, Jin Deok; Kim, Mihwa; D'Agati, Vivette D; Lee, H Thomas

    2006-11-01

    Acute as well as delayed ischemic preconditioning (IPC) provides protection against cardiac and neuronal ischemia reperfusion (IR) injury. This study determined whether delayed preconditioning occurs in the kidney and further elucidated the mechanisms of renal IPC in mice. Mice were subjected to IPC (four cycles of 5 min of ischemia and reperfusion) and then to 30 min of renal ischemia either 15 min (acute IPC) or 24 h (delayed IPC) later. Both acute and delayed renal IPC provided powerful protection against renal IR injury. Inhibition of Akt but not extracellular signal-regulated kinase phosphorylation prevented the protection that was afforded by acute IPC. Neither extracellular signal-regulated kinase nor Akt inhibition prevented protection that was afforded by delayed renal IPC. Pretreatment with an antioxidant, N-(2-mercaptopropionyl)-glycine, to scavenge free radicals prevented the protection that was provided by acute but not delayed renal IPC. Inhibition of protein kinase C or pertussis toxin-sensitive G-proteins attenuated protection from both acute and delayed renal IPC. Delayed renal IPC increased inducible nitric oxide synthase (iNOS) as well as heat-shock protein 27 synthesis, and the renal protective effects of delayed preconditioning were attenuated by a selective inhibitor of iNOS (l-N(6)[1-iminoethyl]lysine). Moreover, delayed IPC was not observed in iNOS knockout mice. Both acute and delayed IPC were independent of A(1) adenosine receptors (AR) as a selective A(1)AR antagonist failed to block preconditioning and acute and delayed preconditioning occurred in mice that lacked A(1)AR. Therefore, this study demonstrated that acute or delayed IPC provides renal protection against IR injury in mice but involves distinct signaling pathways.

  7. Vacua of maximal gauged D=3 supergravities

    International Nuclear Information System (INIS)

    Fischbacher, T; Nicolai, H; Samtleben, H

    2002-01-01

    We analyse the scalar potentials of maximal gauged three-dimensional supergravities which reveal a surprisingly rich structure. In contrast to maximal supergravities in dimensions D≥4, all these theories possess a maximally supersymmetric (N=16) ground state with negative cosmological constant Λ 2 gauged theory, whose maximally supersymmetric groundstate has Λ = 0. We compute the mass spectra of bosonic and fermionic fluctuations around these vacua and identify the unitary irreducible representations of the relevant background (super)isometry groups to which they belong. In addition, we find several stationary points which are not maximally supersymmetric, and determine their complete mass spectra as well. In particular, we show that there are analogues of all stationary points found in higher dimensions, among them are de Sitter (dS) vacua in the theories with noncompact gauge groups SO(5, 3) 2 and SO(4, 4) 2 , as well as anti-de Sitter (AdS) vacua in the compact gauged theory preserving 1/4 and 1/8 of the supersymmetries. All the dS vacua have tachyonic instabilities, whereas there do exist nonsupersymmetric AdS vacua which are stable, again in contrast to the D≥4 theories

  8. Assessing Security Cooperation: Improving Methods to Maximize Effects

    Science.gov (United States)

    2013-03-01

    Glossary, https://dap.dau.mil/glossary/Pages/Default.aspx) 15 Norman K. Denzin and Yvonna S. Lincoln , eds., The Landscape of Qualitative Research...Norman K. Denzin and Yvonna S. Lincoln , eds., Handbook of Qualitative Research (Thousand Oaks: Sage Publications, 1994), 353-359. 20 Maurice Punch...Politics and Ethics in Qualitative Research,” in Handbook of Qualitative Research, ed. Norman K. Denzin and Yvonna S. Lincoln (Thousand Oaks: Sage

  9. Use of the preconditioned conjugate gradient algorithm as a generic solver for mixed-model equations in animal breeding applications.

    Science.gov (United States)

    Tsuruta, S; Misztal, I; Strandén, I

    2001-05-01

    Utility of the preconditioned conjugate gradient algorithm with a diagonal preconditioner for solving mixed-model equations in animal breeding applications was evaluated with 16 test problems. The problems included single- and multiple-trait analyses, with data on beef, dairy, and swine ranging from small examples to national data sets. Multiple-trait models considered low and high genetic correlations. Convergence was based on relative differences between left- and right-hand sides. The ordering of equations was fixed effects followed by random effects, with no special ordering within random effects. The preconditioned conjugate gradient program implemented with double precision converged for all models. However, when implemented in single precision, the preconditioned conjugate gradient algorithm did not converge for seven large models. The preconditioned conjugate gradient and successive overrelaxation algorithms were subsequently compared for 13 of the test problems. The preconditioned conjugate gradient algorithm was easy to implement with the iteration on data for general models. However, successive overrelaxation requires specific programming for each set of models. On average, the preconditioned conjugate gradient algorithm converged in three times fewer rounds of iteration than successive overrelaxation. With straightforward implementations, programs using the preconditioned conjugate gradient algorithm may be two or more times faster than those using successive overrelaxation. However, programs using the preconditioned conjugate gradient algorithm would use more memory than would comparable implementations using successive overrelaxation. Extensive optimization of either algorithm can influence rankings. The preconditioned conjugate gradient implemented with iteration on data, a diagonal preconditioner, and in double precision may be the algorithm of choice for solving mixed-model equations when sufficient memory is available and ease of implementation is

  10. Utility Maximization in Nonconvex Wireless Systems

    CERN Document Server

    Brehmer, Johannes

    2012-01-01

    This monograph formulates a framework for modeling and solving utility maximization problems in nonconvex wireless systems. First, a model for utility optimization in wireless systems is defined. The model is general enough to encompass a wide array of system configurations and performance objectives. Based on the general model, a set of methods for solving utility maximization problems is developed. The development is based on a careful examination of the properties that are required for the application of each method. The focus is on problems whose initial formulation does not allow for a solution by standard convex methods. Solution approaches that take into account the nonconvexities inherent to wireless systems are discussed in detail. The monograph concludes with two case studies that demonstrate the application of the proposed framework to utility maximization in multi-antenna broadcast channels.

  11. The anti-apoptotic effect of fluid mechanics preconditioning by cells membrane and mitochondria in rats brain microvascular endothelial cells.

    Science.gov (United States)

    Tian, Shan; Zhu, Fengping; Hu, Ruiping; Tian, Song; Chen, Xingxing; Lou, Dan; Cao, Bing; Chen, Qiulei; Li, Bai; Li, Fang; Bai, Yulong; Wu, Yi; Zhu, Yulian

    2018-01-01

    Exercise preconditioning is a simple and effective way to prevent ischemia. This paper further provided the mechanism in hemodynamic aspects at the cellular level. To study the anti-apoptotic effects of fluid mechanics preconditioning, Cultured rats brain microvascular endothelial cells were given fluid intervention in a parallel plate flow chamber before oxygen glucose deprivation. It showed that fluid mechanics preconditioning could inhibit the apoptosis of endothelial cells, and this process might be mediated by the shear stress activation of Tie-2 on cells membrane surface and Bcl-2 on the mitochondria surface. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Pharmacokinetics of detomidine administered to horses at rest and after maximal exercise.

    Science.gov (United States)

    Hubbell, J A E; Sams, R A; Schmall, L M; Robertson, J T; Hinchcliff, K W; Muir, W W

    2009-05-01

    Increased doses of detomidine are required to produce sedation in horses after maximal exercise compared to calm or resting horses. To determine if the pharmacokinetics of detomidine in Thoroughbred horses are different when the drug is given during recuperation from a brief period of maximal exercise compared to administration at rest. Six Thoroughbred horses were preconditioned by exercising them on a treadmill. Each horse ran a simulated race at a treadmill speed that caused it to exercise at 120% of its maximal oxygen consumption. One minute after the end of exercise, horses were treated with detomidine. Each horse was treated with the same dose of detomidine on a second occasion a minimum of 14 days later while standing in a stocks. Samples of heparinised blood were obtained at various time points on both occasions. Plasma detomidine concentrations were determined by liquid chromatography-mass spectrometry. The plasma concentration vs. time data were analysed by nonlinear regression analysis. Median back-extrapolated time zero plasma concentration was significantly lower and median plasma half-life and median mean residence time were significantly longer when detomidine was administered after exercise compared to administration at rest. Median volume of distribution was significantly higher after exercise but median plasma clearance was not different between the 2 administrations. Detomidine i.v. is more widely distributed when administered to horses immediately after exercise compared to administration at rest resulting in lower peak plasma concentrations and a slower rate of elimination. The dose requirement to produce an equivalent effect may be higher in horses after exercise than in resting horses and less frequent subsequent doses may be required to produce a sustained effect.

  13. Maximizing band gaps in plate structures

    DEFF Research Database (Denmark)

    Halkjær, Søren; Sigmund, Ole; Jensen, Jakob Søndergaard

    2006-01-01

    periodic plate using Bloch theory, which conveniently reduces the maximization problem to that of a single base cell. Secondly, we construct a finite periodic plate using a number of the optimized base cells in a postprocessed version. The dynamic properties of the finite plate are investigated......Band gaps, i.e., frequency ranges in which waves cannot propagate, can be found in elastic structures for which there is a certain periodic modulation of the material properties or structure. In this paper, we maximize the band gap size for bending waves in a Mindlin plate. We analyze an infinite...... theoretically and experimentally and the issue of finite size effects is addressed....

  14. Singularity Structure of Maximally Supersymmetric Scattering Amplitudes

    DEFF Research Database (Denmark)

    Arkani-Hamed, Nima; Bourjaily, Jacob L.; Cachazo, Freddy

    2014-01-01

    We present evidence that loop amplitudes in maximally supersymmetric (N=4) Yang-Mills theory (SYM) beyond the planar limit share some of the remarkable structures of the planar theory. In particular, we show that through two loops, the four-particle amplitude in full N=4 SYM has only logarithmic ...... singularities and is free of any poles at infinity—properties closely related to uniform transcendentality and the UV finiteness of the theory. We also briefly comment on implications for maximal (N=8) supergravity theory (SUGRA)....

  15. Learning curves for mutual information maximization

    International Nuclear Information System (INIS)

    Urbanczik, R.

    2003-01-01

    An unsupervised learning procedure based on maximizing the mutual information between the outputs of two networks receiving different but statistically dependent inputs is analyzed [S. Becker and G. Hinton, Nature (London) 355, 161 (1992)]. For a generic data model, I show that in the large sample limit the structure in the data is recognized by mutual information maximization. For a more restricted model, where the networks are similar to perceptrons, I calculate the learning curves for zero-temperature Gibbs learning. These show that convergence can be rather slow, and a way of regularizing the procedure is considered

  16. Finding Maximal Pairs with Bounded Gap

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Lyngsø, Rune B.; Pedersen, Christian N. S.

    1999-01-01

    . In this paper we present methods for finding all maximal pairs under various constraints on the gap. In a string of length n we can find all maximal pairs with gap in an upper and lower bounded interval in time O(n log n+z) where z is the number of reported pairs. If the upper bound is removed the time reduces...... to O(n+z). Since a tandem repeat is a pair where the gap is zero, our methods can be seen as a generalization of finding tandem repeats. The running time of our methods equals the running time of well known methods for finding tandem repeats....

  17. Effects of cluster vs. traditional plyometric training sets on maximal-intensity exercise performance

    Directory of Open Access Journals (Sweden)

    Abbas Asadi

    2016-01-01

    Conclusions: Although both plyometric training methods improved lower body maximal-intensity exercise performance, the traditional sets methods resulted in greater adaptations in sprint performance, while the cluster sets method resulted in greater jump and agility adaptations.

  18. Magellan Project: Evolving enhanced operations efficiency to maximize science value

    Science.gov (United States)

    Cheuvront, Allan R.; Neuman, James C.; Mckinney, J. Franklin

    1994-01-01

    Magellan has been one of NASA's most successful spacecraft, returning more science data than all planetary spacecraft combined. The Magellan Spacecraft Team (SCT) has maximized the science return with innovative operational techniques to overcome anomalies and to perform activities for which the spacecraft was not designed. Commanding the spacecraft was originally time consuming because the standard development process was envisioned as manual tasks. The Program understood that reducing mission operations costs were essential for an extended mission. Management created an environment which encouraged automation of routine tasks, allowing staff reduction while maximizing the science data returned. Data analysis and trending, command preparation, and command reviews are some of the tasks that were automated. The SCT has accommodated personnel reductions by improving operations efficiency while returning the maximum science data possible.

  19. Evaluation of the clinical maxim: "If it ain't broke, don't fix it".

    Science.gov (United States)

    Howell-Duffy, Chris; Hrynchak, Patricia K; Irving, Elizabeth L; Mouat, Graham S V; Elliott, David B

    2012-01-01

    A significant number of patients return to optometric practice dissatisfied with their spectacles. An important question is whether any of these cases are preventable. There are several different clinical maxims that are used to modify the subjective refraction when determining the refractive prescription. These maxims aim to improve patient comfort and adaptation and thereby reduce patient dissatisfaction with new spectacles. They are not based on research evidence, but rather on expert opinion gained from clinical experience. The aim of this study was to retrospectively analyze a large number of case records of dissatisfied patients to assess the possible usefulness of the prescribing maxim "if it ain't broke, don't fix it." Three hundred eighteen non-tolerance cases from a university-based Canadian optometric clinic were categorized by a focus group of optometrists. Three prescribing categories were defined and comprised cases in which application of the proposed maxim may have prevented the recheck eye examination; a more limited application of the maxim for one working distance may have been appropriate; and finally scenarios in which the maxim did not work in that the practitioner was judged to have initially followed the maxim, yet patient dissatisfaction was still reported. The remaining unallocated records comprised prescribing situations outside the scope of this study. Approximately 32% of non-tolerance cases were judged to have been preventable by use of the proposed maxim. Furthermore, an additional 10% reduction in recheck cases may have been possible by a more liberal interpretation of the maxim. Conversely, 4% of cases were deemed to comprise scenarios in which the maxim was followed yet the patient returned later to report problems with their spectacles. The prescribing maxim "if it ain't broke, don't fix it" appears to have a role in reducing recheck eye examinations and improving patient satisfaction with new spectacles.

  20. Notch1 Mediates Preconditioning Protection Induced by GPER in Normotensive and Hypertensive Female Rat Hearts

    Directory of Open Access Journals (Sweden)

    Carmine Rocca

    2018-05-01

    Full Text Available G protein-coupled estrogen receptor (GPER is an estrogen receptor expressed in the cardiovascular system. G1, a selective GPER ligand, exerts cardiovascular effects through activation of the PI3K-Akt pathway and Notch signaling in normotensive animals. Here, we investigated whether the G1/GPER interaction is involved in the limitation of infarct size, and improvement of post-ischemic contractile function in female spontaneous hypertensive rat (SHR hearts. In this model, we also studied Notch signaling and key components of survival pathway, namely PI3K-Akt, nitric oxide synthase (NOS and mitochondrial K+-ATP (MitoKATP channels. Rat hearts isolated from female SHR underwent 30 min of global, normothermic ischemia and 120 min of reperfusion. G1 (10 nM alone or specific inhibitors of GPER, PI3K/NOS and MitoKATP channels co-infused with G1, just before I/R, were studied. The involvement of Notch1 was studied by Western blotting. Infarct size and left ventricular pressure were measured. To confirm endothelial-independent G1-induced protection by Notch signaling, H9c2 cells were studied with specific inhibitor, N-[N-(3,5 difluorophenacetyl-L-alanyl]-S-phenylglycine t-butyl ester (DAPT, 5 μM, of this signaling. Using DAPT, we confirmed the involvement of G1/Notch signaling in limiting infarct size in heart of normotensive animals. In the hypertensive model, G1-induced reduction in infarct size and improvement of cardiac function were prevented by the inhibition of GPER, PI3K/NOS, and MitoKATP channels. The involvement of Notch was confirmed by western blot in the hypertensive model and by the specific inhibitor in the normotensive model and cardiac cell line. Our results suggest that GPERs play a pivotal role in mediating preconditioning cardioprotection in normotensive and hypertensive conditions. The G1-induced protection involves Notch1 and is able to activate the survival pathway in the presence of comorbidity. Several pathological conditions

  1. The effect of the phytoestrogen genistein on myocardial protection, preconditioning and oxidative stress.

    Science.gov (United States)

    Sbarouni, Eftihia; Iliodromitis, Efstathios K; Zoga, Anastasia; Vlachou, Georgia; Andreadou, Ioanna; Kremastinos, Dimitrios Th

    2006-08-01

    We have previously shown that estrogen administered in ovariectomized female rabbits significantly reduce myocardial infarct size. We now investigated whether the phytoestrogen genistein similarly protects ischemic myocardium and whether this is associated with its antioxidant properties. In addition, we examined whether genistein abolishes preconditioning, since at high doses, it inhibits tyrosine kinase. We studied five groups of New Zealand white female rabbits. Group A (n = 12) were normal controls, group B (n = 14) were ovariectomized 4 weeks prior to the experiment, group C (n = 10) were ovariectomized and treated with genistein (0.2 mg kg(-1) day(-1) subcutaneously) for 4 weeks before the experiment, group D (n = 12) had intact gonads and were treated with genistein (0.2 mg kg(-1) day(-1) subcutaneously) for 4 weeks before the experiment and group E (n = 8) were ovariectomized 4 weeks prior to the experiment and treated with a single dose of genistein (0.2 mg kg(-1) day(-1) subcutaneously) just prior to the experiment. All animals underwent 30 min of heart ischemia and 120 min of reperfusion, with (subgroup I) or without (subgroup II) preconditioning. Malondialdehyde (MDA) concentration just before the experiment was determined. We found significant differences between the groups-p protect ischemic myocardium in either ovariectomized or non-ovariectomized animals-BII vs CII and AII vs DII, p = NS. There was no significant difference between the preconditioned animals, with intact gonads or ovariectomized (AI vs BI, p = NS), ovariectomized with or without genistein (BI vs CI, p = NS) and non-ovariectomized whether treated with genistein or not (AI vs DI, p = NS). A single dose of genistein did not offer any protection (EII vs BII, p = NS), nor did it modify the preconditioning effect (EI vs BI, p = NS). We found no significant difference in MDA plasma levels between the groups. Genistein, at this dose, does not reduce infarct size per se nor abolishes the

  2. Mixed maximal and explosive strength training in recreational endurance runners.

    Science.gov (United States)

    Taipale, Ritva S; Mikkola, Jussi; Salo, Tiina; Hokka, Laura; Vesterinen, Ville; Kraemer, William J; Nummela, Ari; Häkkinen, Keijo

    2014-03-01

    Supervised periodized mixed maximal and explosive strength training added to endurance training in recreational endurance runners was examined during an 8-week intervention preceded by an 8-week preparatory strength training period. Thirty-four subjects (21-45 years) were divided into experimental groups: men (M, n = 9), women (W, n = 9), and control groups: men (MC, n = 7), women (WC, n = 9). The experimental groups performed mixed maximal and explosive exercises, whereas control subjects performed circuit training with body weight. Endurance training included running at an intensity below lactate threshold. Strength, power, endurance performance characteristics, and hormones were monitored throughout the study. Significance was set at p ≤ 0.05. Increases were observed in both experimental groups that were more systematic than in the control groups in explosive strength (12 and 13% in men and women, respectively), muscle activation, maximal strength (6 and 13%), and peak running speed (14.9 ± 1.2 to 15.6 ± 1.2 and 12.9 ± 0.9 to 13.5 ± 0.8 km Ł h). The control groups showed significant improvements in maximal and explosive strength, but Speak increased only in MC. Submaximal running characteristics (blood lactate and heart rate) improved in all groups. Serum hormones fluctuated significantly in men (testosterone) and in women (thyroid stimulating hormone) but returned to baseline by the end of the study. Mixed strength training combined with endurance training may be more effective than circuit training in recreational endurance runners to benefit overall fitness that may be important for other adaptive processes and larger training loads associated with, e.g., marathon training.

  3. Maximizing the Range of a Projectile.

    Science.gov (United States)

    Brown, Ronald A.

    1992-01-01

    Discusses solutions to the problem of maximizing the range of a projectile. Presents three references that solve the problem with and without the use of calculus. Offers a fourth solution suitable for introductory physics courses that relies more on trigonometry and the geometry of the problem. (MDH)

  4. Robust Utility Maximization Under Convex Portfolio Constraints

    International Nuclear Information System (INIS)

    Matoussi, Anis; Mezghani, Hanen; Mnif, Mohamed

    2015-01-01

    We study a robust maximization problem from terminal wealth and consumption under a convex constraints on the portfolio. We state the existence and the uniqueness of the consumption–investment strategy by studying the associated quadratic backward stochastic differential equation. We characterize the optimal control by using the duality method and deriving a dynamic maximum principle

  5. Ehrenfest's Lottery--Time and Entropy Maximization

    Science.gov (United States)

    Ashbaugh, Henry S.

    2010-01-01

    Successful teaching of the Second Law of Thermodynamics suffers from limited simple examples linking equilibrium to entropy maximization. I describe a thought experiment connecting entropy to a lottery that mixes marbles amongst a collection of urns. This mixing obeys diffusion-like dynamics. Equilibrium is achieved when the marble distribution is…

  6. Reserve design to maximize species persistence

    Science.gov (United States)

    Robert G. Haight; Laurel E. Travis

    2008-01-01

    We develop a reserve design strategy to maximize the probability of species persistence predicted by a stochastic, individual-based, metapopulation model. Because the population model does not fit exact optimization procedures, our strategy involves deriving promising solutions from theory, obtaining promising solutions from a simulation optimization heuristic, and...

  7. Maximal indecomposable past sets and event horizons

    International Nuclear Information System (INIS)

    Krolak, A.

    1984-01-01

    The existence of maximal indecomposable past sets MIPs is demonstrated using the Kuratowski-Zorn lemma. A criterion for the existence of an absolute event horizon in space-time is given in terms of MIPs and a relation to black hole event horizon is shown. (author)

  8. Maximization of eigenvalues using topology optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2000-01-01

    to localized modes in low density areas. The topology optimization problem is formulated using the SIMP method. Special attention is paid to a numerical method for removing localized eigenmodes in low density areas. The method is applied to numerical examples of maximizing the first eigenfrequency, One example...

  9. Maximizing Resource Utilization in Video Streaming Systems

    Science.gov (United States)

    Alsmirat, Mohammad Abdullah

    2013-01-01

    Video streaming has recently grown dramatically in popularity over the Internet, Cable TV, and wire-less networks. Because of the resource demanding nature of video streaming applications, maximizing resource utilization in any video streaming system is a key factor to increase the scalability and decrease the cost of the system. Resources to…

  10. A THEORY OF MAXIMIZING SENSORY INFORMATION

    NARCIS (Netherlands)

    Hateren, J.H. van

    1992-01-01

    A theory is developed on the assumption that early sensory processing aims at maximizing the information rate in the channels connecting the sensory system to more central parts of the brain, where it is assumed that these channels are noisy and have a limited dynamic range. Given a stimulus power

  11. Maximizing scientific knowledge from randomized clinical trials

    DEFF Research Database (Denmark)

    Gustafsson, Finn; Atar, Dan; Pitt, Bertram

    2010-01-01

    Trialists have an ethical and financial responsibility to plan and conduct clinical trials in a manner that will maximize the scientific knowledge gained from the trial. However, the amount of scientific information generated by randomized clinical trials in cardiovascular medicine is highly vari...

  12. A Model of College Tuition Maximization

    Science.gov (United States)

    Bosshardt, Donald I.; Lichtenstein, Larry; Zaporowski, Mark P.

    2009-01-01

    This paper develops a series of models for optimal tuition pricing for private colleges and universities. The university is assumed to be a profit maximizing, price discriminating monopolist. The enrollment decision of student's is stochastic in nature. The university offers an effective tuition rate, comprised of stipulated tuition less financial…

  13. Logit Analysis for Profit Maximizing Loan Classification

    OpenAIRE

    Watt, David L.; Mortensen, Timothy L.; Leistritz, F. Larry

    1988-01-01

    Lending criteria and loan classification methods are developed. Rating system breaking points are analyzed to present a method to maximize loan revenues. Financial characteristics of farmers are used as determinants of delinquency in a multivariate logistic model. Results indicate that debt-to-asset and operating ration are most indicative of default.

  14. Developing maximal neuromuscular power: Part 1--biological basis of maximal power production.

    Science.gov (United States)

    Cormie, Prue; McGuigan, Michael R; Newton, Robert U

    2011-01-01

    This series of reviews focuses on the most important neuromuscular function in many sport performances, the ability to generate maximal muscular power. Part 1 focuses on the factors that affect maximal power production, while part 2, which will follow in a forthcoming edition of Sports Medicine, explores the practical application of these findings by reviewing the scientific literature relevant to the development of training programmes that most effectively enhance maximal power production. The ability of the neuromuscular system to generate maximal power is affected by a range of interrelated factors. Maximal muscular power is defined and limited by the force-velocity relationship and affected by the length-tension relationship. The ability to generate maximal power is influenced by the type of muscle action involved and, in particular, the time available to develop force, storage and utilization of elastic energy, interactions of contractile and elastic elements, potentiation of contractile and elastic filaments as well as stretch reflexes. Furthermore, maximal power production is influenced by morphological factors including fibre type contribution to whole muscle area, muscle architectural features and tendon properties as well as neural factors including motor unit recruitment, firing frequency, synchronization and inter-muscular coordination. In addition, acute changes in the muscle environment (i.e. alterations resulting from fatigue, changes in hormone milieu and muscle temperature) impact the ability to generate maximal power. Resistance training has been shown to impact each of these neuromuscular factors in quite specific ways. Therefore, an understanding of the biological basis of maximal power production is essential for developing training programmes that effectively enhance maximal power production in the human.

  15. Understanding Violations of Gricean Maxims in Preschoolers and Adults

    Directory of Open Access Journals (Sweden)

    Mako eOkanda

    2015-07-01

    Full Text Available This study used a revised Conversational Violations Test to examine Gricean maxim violations in 4- to 6-year-old Japanese children and adults. Participants’ understanding of the following maxims was assessed: be informative (first maxim of quantity, avoid redundancy (second maxim of quantity, be truthful (maxim of quality, be relevant (maxim of relation, avoid ambiguity (second maxim of manner, and be polite (maxim of politeness. Sensitivity to violations of Gricean maxims increased with age: 4-year-olds’ understanding of maxims was near chance, 5-year-olds understood some maxims (first maxim of quantity and maxims of quality, relation, and manner, and 6-year-olds and adults understood all maxims. Preschoolers acquired the maxim of relation first and had the greatest difficulty understanding the second maxim of quantity. Children and adults differed in their comprehension of the maxim of politeness. The development of the pragmatic understanding of Gricean maxims and implications for the construction of developmental tasks from early childhood to adulthood are discussed.

  16. A calderón-preconditioned single source combined field integral equation for analyzing scattering from homogeneous penetrable objects

    KAUST Repository

    Valdé s, Felipe; Andriulli, Francesco P.; Bagci, Hakan; Michielssen, Eric

    2011-01-01

    A new regularized single source equation for analyzing scattering from homogeneous penetrable objects is presented. The proposed equation is a linear combination of a Calderón-preconditioned single source electric field integral equation and a

  17. PRECONDITIONED CONJUGATE-GRADIENT 2 (PCG2), a computer program for solving ground-water flow equations

    Science.gov (United States)

    Hill, Mary C.

    1990-01-01

    This report documents PCG2 : a numerical code to be used with the U.S. Geological Survey modular three-dimensional, finite-difference, ground-water flow model . PCG2 uses the preconditioned conjugate-gradient method to solve the equations produced by the model for hydraulic head. Linear or nonlinear flow conditions may be simulated. PCG2 includes two reconditioning options : modified incomplete Cholesky preconditioning, which is efficient on scalar computers; and polynomial preconditioning, which requires less computer storage and, with modifications that depend on the computer used, is most efficient on vector computers . Convergence of the solver is determined using both head-change and residual criteria. Nonlinear problems are solved using Picard iterations. This documentation provides a description of the preconditioned conjugate gradient method and the two preconditioners, detailed instructions for linking PCG2 to the modular model, sample data inputs, a brief description of PCG2, and a FORTRAN listing.

  18. Parallelization of the preconditioned IDR solver for modern multicore computer systems

    Science.gov (United States)

    Bessonov, O. A.; Fedoseyev, A. I.

    2012-10-01

    This paper present the analysis, parallelization and optimization approach for the large sparse matrix solver CNSPACK for modern multicore microprocessors. CNSPACK is an advanced solver successfully used for coupled solution of stiff problems arising in multiphysics applications such as CFD, semiconductor transport, kinetic and quantum problems. It employs iterative IDR algorithm with ILU preconditioning (user chosen ILU preconditioning order). CNSPACK has been successfully used during last decade for solving problems in several application areas, including fluid dynamics and semiconductor device simulation. However, there was a dramatic change in processor architectures and computer system organization in recent years. Due to this, performance criteria and methods have been revisited, together with involving the parallelization of the solver and preconditioner using Open MP environment. Results of the successful implementation for efficient parallelization are presented for the most advances computer system (Intel Core i7-9xx or two-processor Xeon 55xx/56xx).

  19. The Conceptual Preconditions of Studying Collective Professional Mobility of Management Personnel

    Directory of Open Access Journals (Sweden)

    Doronin Andrii V.

    2016-08-01

    Full Text Available The preconditions and problems of developing the concept of the study and transformation of collective professional mobility of management personnel are generalized. The necessity of specifying the content and structure of the scientific and methodological concept of «paradigm» is justified. The possibility of using philosophy and economic theory to determine the initial ideas on the development of technique for studying collective professional mobility of management personnel are analyzed; contradictions, which resolution would create a constructive theoretical basis of such a study are revealed. The need to focus on the interdisciplinary approach in the development of the conceptual preconditions of studying collective professional mobility is substantiated. The versions of the world view allowing to ensure productive discussions of representatives of various scientific disciplines at the phenomenological stage of building a new paradigm are developed.

  20. [Octanol preconditioning alleviates mouse cardiomyocyte swelling induced by simulated ischemia/reperfusion challenge in vitro].

    Science.gov (United States)

    Luo, Yukun; Fang, Jun; Fan, Lin; Lin, Chaogui; Chen, Zhaoyang; Chen, Lianglong

    2012-10-01

    To investigate the role of connexin 43-formed hemichannels in cell volume regulation induced by simulated ischemia/reperfusion (SI/R). Mouse cardiomyocytes isolated on a Langendorff apparatus with enzyme solution were aliquoted into control, SI/R and SI/R +octanol groups. Calcein-AM was used to stain the cells and the cell volume was measured with confocal microscope by stack scanning. Trypan blue was used to measure the cell viability after the treatments. Calcein-AM staining and cofocal microscopy yielded stable and reproducible results for cell volume measurement. Mouse cardiomyocytes subjected to simulated SI/R showed obvious cell swelling as compared with the control cells [(126∓6)% vs 100%, Poctanol preconditioning significantly attenuated the cell swelling [(113∓6)%, Poctanol preconditioning obviously reduced the viability of the cells with SI/R challenge [(31∓2)%, Poctanol can alleviate the cell swelling to enhance the viability of the cardiomyocytes following SI/R.

  1. Microglial ablation and lipopolysaccharide preconditioning affects pilocarpine-induced seizures in mice

    Energy Technology Data Exchange (ETDEWEB)

    Mirrione, M.M.; Mirrione, M.M.; Konomosa, D.K.; Ioradanis, G.; Dewey, S.L.; Agzzid, A.; Heppnerd, F.L.; Tsirka, St.E.

    2010-04-01

    Activated microglia have been associated with neurodegeneration in patients and in animal models of Temporal Lobe Epilepsy (TLE), however their precise functions as neurotoxic or neuroprotective is a topic of significant investigation. To explore this, we examined the effects of pilocarpine-induced seizures in transgenic mice where microglia/macrophages were conditionally ablated. We found that unilateral ablation of microglia from the dorsal hippocampus did not alter acute seizure sensitivity. However, when this procedure was coupled with lipopolysaccharide (LPS) preconditioning (1 mg/kg given 24 h prior to acute seizure), we observed a significant pro-convulsant phenomenon. This effect was associated with lower metabolic activation in the ipsilateral hippocampus during acute seizures, and could be attributed to activity in the mossy fiber pathway. These findings reveal that preconditioning with LPS 24 h prior to seizure induction may have a protective effect which is abolished by unilateral hippocampal microglia/macrophage ablation.

  2. Parallelized preconditioned BiCGStab solution of sparse linear system equations in F-COBRA-TF

    International Nuclear Information System (INIS)

    Geemert, Rene van; Glück, Markus; Riedmann, Michael; Gabriel, Harry

    2011-01-01

    Recently, the in-house development of a preconditioned and parallelized BiCGStab solver has been pursued successfully in AREVA’s advanced sub-channel code F-COBRA-TF. This solver can be run either in a sequential computation mode on a single CPU, or in a parallel computation mode on multiple parallel CPUs. The developed procedure enables the computation of several thousands of successive sparse linear system solutions in F-COBRA-TF with acceptable wall clock run times. The current paper provides general information about F-COBRA-TF in terms of modeling capabilities and application areas, and points out where the relevance arises for the efficient iterative solution of sparse linear systems. Furthermore, the preconditioning and parallelization strategies in the developed BiCGStab iterative solution approach are discussed. The paper is concluded with a number of verification examples. (author)

  3. Comparison of preconditioned generalized conjugate gradient methods to two-dimensional neutron and photon transport equation

    International Nuclear Information System (INIS)

    Chen, G.S.

    1997-01-01

    We apply and compare the preconditioned generalized conjugate gradient methods to solve the linear system equation that arises in the two-dimensional neutron and photon transport equation in this paper. Several subroutines are developed on the basis of preconditioned generalized conjugate gradient methods for time-independent, two-dimensional neutron and photon transport equation in the transport theory. These generalized conjugate gradient methods are used. TFQMR (transpose free quasi-minimal residual algorithm), CGS (conjuage gradient square algorithm), Bi-CGSTAB (bi-conjugate gradient stabilized algorithm) and QMRCGSTAB (quasi-minimal residual variant of bi-conjugate gradient stabilized algorithm). These sub-routines are connected to computer program DORT. Several problems are tested on a personal computer with Intel Pentium CPU. (author)

  4. Protective effects of endoplasmic reticulum stress preconditioning on hippocampal neurons in rats with status epilepticus

    Directory of Open Access Journals (Sweden)

    Yi ZHANG

    2014-12-01

    Full Text Available Objective To evaluate the protective effects of endoplasmic reticulum stress preconditioning induced by 2-deoxyglucose (2-DG on hippocampal neurons of rats with status epilepticus (SE and the possible mechanism.  Methods Ninety Sprague-Dawley (SD rats were randomly enrolled into preconditioning group (N = 30, SE group (N = 30 and control group (N = 30. Each group was divided into 6 subsets (N = 5 according to six time points (before seizure, 6 h, 12 h, 1 d, 2 d and 7 d after seizure. The preconditioning group was administered 2-DG intraperitoneally with a dose of 150 mg/kg for 7 days, and the lithium-pilocarpine induced SE rat model was established on both preconditioning group and SE group. The rats were sacrificed at the above six time points, and the brains were removed to make paraffin sections. Nissl staining was performed by toluidine blue to evaluate the hippocampal neuronal damage after seizure, and the number of survival neurons in hippocampal CA1 and CA3 regions of the rats were counted. Immunohistochemical staining was performed to detect the expressions of glucose regulated protein 78 (GRP78 and X-box binding protein 1 (XBP-1 in hippocampal CA3 region of the rats.  Results The number of survival neurons in preconditioning group was much more than that in SE group at 7 d after seizure (t = 5.353, P = 0.000, and was more obvious in CA1 region. There was no significant hippocampal neuronal damage in control group. The expressions of GRP78 and XBP-1 in CA3 region of hippocampus in SE group at 6 h after seizure were significantly higher than that in control group (P = 0.000, and then kept increasing until reaching the peak at 2 d (P = 0.000, for all. The expressions of GRP78 and XBP-1 in hippocampal CA3 region in preconditioning group were significantly higher than that in control group before seizure (P = 0.000, for all. The level of GRP78 maintained the highest at 24 h and 2 d after seizure (P = 0.000, for all, while the XBP-1 level

  5. Pharmacological delayed preconditioning against ischaemia-induced ventricular arrhythmias: effect of an adenosine A1-receptor agonist

    OpenAIRE

    Tissier, Renaud; Souktani, Rachid; Parent de Curzon, Olivier; Lellouche, Nicolas; Henry, Patrick; Giudicelli, Jean-François; Berdeaux, Alain; Ghaleh, Bijan

    2001-01-01

    The goal of this study was to investigate the effects of the delayed pharmacological preconditioning produced by an adenosine A1-receptor agonist (A1-DPC) against ventricular arrhythmias induced by ischaemia and reperfusion, compared to those of ischaemia-induced delayed preconditioning (I-DPC).Eighty-nine instrumented conscious rabbits underwent a 2 consecutive days protocol. On day 1, rabbits were randomly divided into four groups: ‘Control' (saline, i.v.), ‘I-DPC' (six 4-min coronary arter...

  6. MICROARRAY PROFILE OF SEIZURE DAMAGE-REFRACTORY HIPPOCAMPAL CA3 IN A MOUSE MODEL OF EPILEPTIC PRECONDITIONING

    OpenAIRE

    HATAZAKI, S.; BELLVER-ESTELLES, C.; JIMENEZ-MATEOS, E. M.; MELLER, R.; BONNER, C.; MURPHY, N.; MATSUSHIMA, S.; TAKI, W.; PREHN, J. H. M.; SIMON, R. P.; HENSHALL, D. C.

    2007-01-01

    A neuroprotected state can be acquired by preconditioning brain with a stimulus that is subthreshold for damage (tolerance). Acquisition of tolerance involves coordinate, bi-directional changes to gene expression levels and the re-programmed phenotype is determined by the preconditioning stimulus. While best studied in ischemic brain there is evidence brief seizures can confer tolerance against prolonged seizures (status epilepticus). Presently, we developed a model of epileptic preconditioni...

  7. Preconditions of commercial use in tourism of individual´s death

    OpenAIRE

    TŮMOVÁ, Blanka

    2008-01-01

    This bachelor thesis deals with the processing the theme Dark Tourism introducing an unusual and so far not very well-known type of tourism in the Czech Republic. The concept Dark Tourism (also known as Thanatourism) refers to visiting sites which offer a presentation of death or suffering and it is identified with visitations to places where tragedies or historically noteworthy death has occurred and that continue to impact our lives. This thesis researches preconditions of commercial use in...

  8. Comparison of preconditioned generalized conjugate gradient methods to two-dimensional neutron and photon transport equation

    International Nuclear Information System (INIS)

    Chen, G.S.; Yang, D.Y.

    1998-01-01

    We apply and compare the preconditioned generalized conjugate gradient methods to solve the linear system equation that arises in the two-dimensional neutron and photon transport equation in this paper. Several subroutines are developed on the basis of preconditioned generalized conjugate gradient methods for time-independent, two-dimensional neutron and photon transport equation in the transport theory. These generalized conjugate gradient methods are used: TFQMR (transpose free quasi-minimal residual algorithm) CGS (conjugate gradient square algorithm), Bi-CGSTAB (bi-conjugate gradient stabilized algorithm) and QMRCGSTAB (quasi-minimal residual variant of bi-conjugate gradient stabilized algorithm). These subroutines are connected to computer program DORT. Several problems are tested on a personal computer with Intel Pentium CPU. The reasons to choose the generalized conjugate gradient methods are that the methods have better residual (equivalent to error) control procedures in the computation and have better convergent rate. The pointwise incomplete LU factorization ILU, modified pointwise incomplete LU factorization MILU, block incomplete factorization BILU and modified blockwise incomplete LU factorization MBILU are the preconditioning techniques used in the several testing problems. In Bi-CGSTAB, CGS, TFQMR and QMRCGSTAB method, we find that either CGS or Bi-CGSTAB method combined with preconditioner MBILU is the most efficient algorithm in these methods in the several testing problems. The numerical solution of flux by preconditioned CGS and Bi-CGSTAB methods has the same result as those from Cray computer, obtained by either the point successive relaxation method or the line successive relaxation method combined with Gaussian elimination

  9. An Unsteady Preconditioning Scheme Based on Convective-Upwind Split-Pressure (CUSP) Artificial Dissipation

    Science.gov (United States)

    2014-01-07

    this can have a disastrous effect on convergence rate. Even if steady state is obtained for low Mach number flows (after many iterations ), the results...rally lead do a diagonally dominant left-hand-side matrix, which causes stability problems for implicit Gauss - Seidel schemes. For this reason, matrix... convergence at the stagnation point. The iterations for each airfoil is also reported in Fig. 2. Without preconditioning, dramatic efficiency problems are seen

  10. Static condensation, partial orthogonalization of basis functions, and ILU preconditioning in the hp-FEM

    Czech Academy of Sciences Publication Activity Database

    Vejchodský, Tomáš; Šolín, Pavel

    2008-01-01

    Roč. 218, č. 1 (2008), s. 192-200 ISSN 0377-0427 R&D Projects: GA AV ČR IAA100760702; GA ČR GA102/05/0629; GA ČR(CZ) GA102/07/0496 Institutional research plan: CEZ:AV0Z10190503; CEZ:AV0Z20570509 Keywords : static condensation of internal degrees of freedom * orthogonalization * ILU preconditioning Subject RIV: BA - General Mathematics Impact factor: 1.048, year: 2008

  11. Historical Preconditions and Factors for Development of International Relations between UAE and African Countries

    Directory of Open Access Journals (Sweden)

    A K Voronkov

    2012-06-01

    Full Text Available The article focuses on analyses of preconditions for development of international relations between UAE and African countries including geographical location of the UAE, naval and ship building skills of the Persian gulf Arabs, participation of both Eastern Africa and Persian Gulf in the Indian ocean trade as well as influence on its development of external factors such as Islamic expansion and colonial policies of Britain and Portugal.

  12. PRECONDITIONS FOR THE INTRODUCTION OF ACCOUNTING AND TAXATION OF CRYPTOCURRENCIES TRANSACTIONS IN UKRAINE

    OpenAIRE

    Kostyuchenko V.; Malinovskaya A.; Mamonova A.

    2018-01-01

    Introduction. The worldwide expansion of digital technologies and the development of the cyber economy led to emergence of a new digital assets – the cryptographic currency that rapidly growing popularity. The phenomenon of cryptocurrency is relatively new and little investigated. Purpose. The purpose of the article is to substantiate the preconditions for the introduction of accounting and taxation of transactions with cryptic currencies in Ukraine. Results. The article considers the...

  13. Low-energy shock wave preconditioning reduces renal ischemic reperfusion injury caused by renal artery occlusion.

    Science.gov (United States)

    Xue, Yuquan; Xu, Zhibin; Chen, Haiwen; Gan, Weimin; Chong, Tie

    2017-07-01

    To evaluate whether low energy shock wave preconditioning could reduce renal ischemic reperfusion injury caused by renal artery occlusion. The right kidneys of 64 male Sprague Dawley rats were removed to establish an isolated kidney model. The rats were then divided into four treatment groups: Group 1 was the sham treatment group; Group 2, received only low-energy (12 kv, 1 Hz, 200 times) shock wave preconditioning; Group 3 received the same low-energy shock wave preconditioning as Group 2, and then the left renal artery was occluded for 45 minutes; and Group 4 had the left renal artery occluded for 45 minutes. At 24 hours and one-week time points after reperfusion, serum inducible nitric oxide synthase (iNOS), neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), creatinine (Cr), and cystatin C (Cys C) levels were measured, malondialdehyde (MDA) in kidney tissue was detected, and changes in nephric morphology were evaluated by light and electron microscopy. Twenty-four hours after reperfusion, serum iNOS, NGAL, Cr, Cys C, and MDA levels in Group 3 were significantly lower than those in Group 4; light and electron microscopy showed that the renal tissue injury in Group 3 was significantly lighter than that in Group 4. One week after reperfusion, serum NGAL, KIM-1, and Cys C levels in Group 3 were significantly lower than those in Group 4. Low-energy shock wave preconditioning can reduce renal ischemic reperfusion injury caused by renal artery occlusion in an isolated kidney rat model.

  14. Preconditions for Introduction and Prospects for Implementation of the Inflation Targeting Regime in Ukraine

    OpenAIRE

    Hladkykh Dmytro M.

    2017-01-01

    The article is aimed at studying the preconditions for introduction, the main problems and prospects for implementation of the inflation targeting regime in Ukraine. In 2014, the country got into a crisis that affected at once the currency market, the banking system and the real sector, resulting in devaluations, bank failures, decreasing GDP, growing prices. One of the responses to the financial challenges was the transition to inflationary targeting, which led to a slowdown in inflation in ...

  15. Electroacupuncture preconditioning-induced neuroprotection may be mediated by glutamate transporter type 2

    OpenAIRE

    Zhu, Xiaoling; Yin, Jinbo; Li, Liaoliao; Ma, Lei; Tan, Hongying; Deng, Jiao; Chen, Shaoyang; Zuo, Zhiyi

    2013-01-01

    Electroacupuncture has been shown to induce a preconditioning effect in the brain. The mechanisms for this protection are not fully elucidated. We hypothesize that this protection is mediated by excitatory amino acid transporters (EAATs) that have been shown to be neuroprotective. To test this hypothesis, two-month old male Sprague-Dawley rats and EAAT type 3 (EAAT3) knockout mice received or did not receive 30-min electroacupuncture once a day for 5 consecutive days. They were subjected to a...

  16. Acute effects of remote ischemic preconditioning on cutaneous microcirculation - a controlled prospective cohort study

    Directory of Open Access Journals (Sweden)

    Kraemer Robert

    2011-11-01

    Full Text Available Abstract Background Therapeutic strategies aiming to reduce ischemia/reperfusion injury by conditioning tissue tolerance against ischemia appear attractive not only from a scientific perspective, but also in clinics. Although previous studies indicate that remote ischemic intermittent preconditioning (RIPC is a systemic phenomenon, only a few studies have focused on the elucidation of its mechanisms of action especially in the clinical setting. Therefore, the aim of this study is to evaluate the acute microcirculatory effects of remote ischemic preconditioning on a distinct cutaneous location at the lower extremity which is typically used as a harvesting site for free flap reconstructive surgery in a human in-vivo setting. Methods Microcirculatory data of 27 healthy subjects (25 males, age 24 ± 4 years, BMI 23.3 were evaluated continuously at the anterolateral aspect of the left thigh during RIPC using combined Laser-Doppler and photospectrometry (Oxygen-to-see, Lea Medizintechnik, Germany. After baseline microcirculatory measurement, remote ischemia was induced using a tourniquet on the contralateral upper arm for three cycles of 5 min. Results After RIPC, tissue oxygen saturation and capillary blood flow increased up to 29% and 35% during the third reperfusion phase versus baseline measurement, respectively (both p = 0.001. Postcapillary venous filling pressure decreased statistically significant by 16% during second reperfusion phase (p = 0.028. Conclusion Remote intermittent ischemic preconditioning affects cutaneous tissue oxygen saturation, arterial capillary blood flow and postcapillary venous filling pressure at a remote cutaneous location of the lower extremity. To what extent remote preconditioning might ameliorate reperfusion injury in soft tissue trauma or free flap transplantation further clinical trials have to evaluate. Trial registration ClinicalTrials.gov: NCT01235286

  17. The precondition of social mobility in Ignalina NPP and its area

    International Nuclear Information System (INIS)

    Mikshys, A.

    1998-01-01

    In the paper some preconditions of social mobility in the northern Lithuania (Ignalina nuclear power plant) and in its area are analyzed. The results of the sociological research reveal the desire of some part of the inhabitants of the nuclear power plant area to change their social status and the place of residence. The difficult social and demographically situation in this region as significant is noted. The author proposes some mean for the normalization of this situation. (author)

  18. Preconditioning of two-by-two block matrix systems with square matrix blocks, with applications

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe

    2017-01-01

    Roč. 62, č. 6 (2017), s. 537-559 ISSN 0862-7940. [SNA´17 - Seminar on numerical analysis. Ostrava, 30.01.2017-03.02.2017] Institutional support: RVO:68145535 Keywords : preconditioning * Schur complement * transformation * optimal control * implicit time integration Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 0.618, year: 2016 http://articles.math.cas.cz/10.21136/AM.2017.0222-17/?type=F

  19. An efficient community detection algorithm using greedy surprise maximization

    International Nuclear Information System (INIS)

    Jiang, Yawen; Jia, Caiyan; Yu, Jian

    2014-01-01

    Community detection is an important and crucial problem in complex network analysis. Although classical modularity function optimization approaches are widely used for identifying communities, the modularity function (Q) suffers from its resolution limit. Recently, the surprise function (S) was experimentally proved to be better than the Q function. However, up until now, there has been no algorithm available to perform searches to directly determine the maximal surprise values. In this paper, considering the superiority of the S function over the Q function, we propose an efficient community detection algorithm called AGSO (algorithm based on greedy surprise optimization) and its improved version FAGSO (fast-AGSO), which are based on greedy surprise optimization and do not suffer from the resolution limit. In addition, (F)AGSO does not need the number of communities K to be specified in advance. Tests on experimental networks show that (F)AGSO is able to detect optimal partitions in both simple and even more complex networks. Moreover, algorithms based on surprise maximization perform better than those algorithms based on modularity maximization, including Blondel–Guillaume–Lambiotte–Lefebvre (BGLL), Clauset–Newman–Moore (CNM) and the other state-of-the-art algorithms such as Infomap, order statistics local optimization method (OSLOM) and label propagation algorithm (LPA). (paper)

  20. Formation Control of the MAXIM L2 Libration Orbit Mission

    Science.gov (United States)

    Folta, David; Hartman, Kate; Howell, Kathleen; Marchand, Belinda

    2004-01-01

    The Micro-Arcsecond X-ray Imaging Mission (MAXIM), a proposed concept for the Structure and Evolution of the Universe (SEU) Black Hole Imager mission, is designed to make a ten million-fold improvement in X-ray image clarity of celestial objects by providing better than 0.1 micro-arcsecond imaging. Currently the mission architecture comprises 25 spacecraft, 24 as optics modules and one as the detector, which will form sparse sub-apertures of a grazing incidence X-ray interferometer covering the 0.3-10 keV bandpass. This formation must allow for long duration continuous science observations and also for reconfiguration that permits re-pointing of the formation. To achieve these mission goals, the formation is required to cooperatively point at desired targets. Once pointed, the individual elements of the MAXIM formation must remain stable, maintaining their relative positions and attitudes below a critical threshold. These pointing and formation stability requirements impact the control and design of the formation. In this paper, we provide analysis of control efforts that are dependent upon the stability and the configuration and dimensions of the MAXIM formation. We emphasize the utilization of natural motions in the Lagrangian regions to minimize the control efforts and we address continuous control via input feedback linearization (IFL). Results provide control cost, configuration options, and capabilities as guidelines for the development of this complex mission.

  1. Hypoperfusion Induced by Preconditioning Treadmill Training in Hyper-Early Reperfusion After Cerebral Ischemia: A Laser Speckle Imaging Study.

    Science.gov (United States)

    He, Zhijie; Lu, Hongyang; Yang, Xiaojiao; Zhang, Li; Wu, Yi; Niu, Wenxiu; Ding, Li; Wang, Guili; Tong, Shanbao; Jia, Jie

    2018-01-01

    Exercise preconditioning induces neuroprotective effects during cerebral ischemia and reperfusion, which involves the recovery of cerebral blood flow (CBF). Mechanisms underlying the neuroprotective effects of re-established CBF following ischemia and reperfusion are unclear. The present study investigated CBF in hyper-early stage of reperfusion by laser speckle contrast imaging, a full-field high-resolution optical imaging technique. Rats with or without treadmill training were subjected to middle cerebral artery occlusion followed by reperfusion. CBF in arteries, veins, and capillaries in hyper-early stage of reperfusion (1, 2, and 3 h after reperfusion) and in subacute stage (24 h after reperfusion) were measured. Neurological scoring and 2,3,5-triphenyltetrazolium chloride staining were further applied to determine the neuroprotective effects of exercise preconditioning. In hyper-early stage of reperfusion, CBF in the rats with exercise preconditioning was reduced significantly in arteries and veins, respectively, compared to rats with no exercise preconditioning. Capillary CBF remained stable in the hyper-early stage of reperfusion, though it increased significantly 24 h after reperfusion in the rats with exercise preconditioning. As a neuroprotective strategy, exercise preconditioning reduced the blood perfusion of arteries and veins in the hyper-early stage of reperfusion, which indicated intervention-induced neuroprotective hypoperfusion after reperfusion onset.

  2. Improving the accuracy of the Calderón preconditioned CFIE by using a mixed discretization

    KAUST Repository

    Cools, Kristof; Andriulli, Francesco P.; Ylä -Oijala, Pasi; Bagci, Hakan; De Zutter, Danï l; Michielssen, Eric

    2010-01-01

    The scattering of time-harmonic electromagnetic waves by perfect electrically conducting (PEC) objects can be modeled by several boundary integral equations. The most prominent ones are the electric and magnetic field integral equations (EFIE and MFIE). The former is applicable to both open and closed structures, whereas the latter is applicable to only closed structures. © 2010 IEEE.

  3. Improving the accuracy of the Calderón preconditioned CFIE by using a mixed discretization

    KAUST Repository

    Cools, Kristof

    2010-07-01

    The scattering of time-harmonic electromagnetic waves by perfect electrically conducting (PEC) objects can be modeled by several boundary integral equations. The most prominent ones are the electric and magnetic field integral equations (EFIE and MFIE). The former is applicable to both open and closed structures, whereas the latter is applicable to only closed structures. © 2010 IEEE.

  4. Pharmacological preconditioning by milrinone: memory preserving and neuroprotective effect in ischemia-reperfusion injury in mice.

    Science.gov (United States)

    Saklani, Reetu; Jaggi, Amteshwar; Singh, Nirmal

    2010-07-01

    We tested the neuroprotective effect of milrinone, a phosphodiesterase III inhibitor, in pharmacological preconditioning. Bilateral carotid artery occlusion for 12 min followed by reperfusion for 24 h produced ischemia-reperfusion (I/R) cerebral injury in male Swiss albino mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was assessed using the Morris water maze test, and motor coordination was evaluated using the inclined beam walking test, rota-rod test, and lateral push test. Milrinone (50 microg/kg & 100 microg/kg i.v.) was administered 24 h before surgery in a separate group of animals to induce pharmacological preconditioning. I/R increased cerebral infarct size and impaired memory and motor coordination. Milrinone treatment significantly decreased cerebral infarct size and reversed I/R-induced impairments in memory and motor coordination. This neuroprotective effect was blocked by ruthenium red (3 mg/kg, s.c.), an intracellular ryanodine receptor blocker. These findings indicate that milrinone preconditioning exerts a marked neuroprotective effect on the ischemic brain, putatively due to increased intracellular calcium levels activating calcium-sensitive signal transduction cascades.

  5. Arctic atmospheric preconditioning: do not rule out shortwave radiation just yet

    Science.gov (United States)

    Sedlar, J.

    2017-12-01

    Springtime atmospheric preconditioning of Arctic sea ice for enhanced or buffered sea ice melt during the subsequent melt year has received considerable research focus in recent years. A general consensus points to enhanced poleward atmospheric transport of moisture and heat during spring, effectively increasing the emission of longwave radiation to the surface. Studies have essentially ruled out the role of shortwave radiation as an effective preconditioning mechanism because of the relatively weak incident solar radiation and high surface albedo from sea ice and snow during spring. These conclusions, however, are derived primarily from atmospheric reanalysis data, which may not always represent an accurate depiction of the Arctic climate system. Here, observations of top of atmosphere radiation from state of the art satellite sensors are examined and compared with reanalysis and climate model data to examine the differences in the spring radiative budget over the Arctic Ocean for years with extreme low/high ice extent at the end of the ice melt season (September). Distinct biases are observed between satellite-based measurements and reanalysis/models, particularly for the amount of shortwave radiation trapped (warming effect) within the Arctic climate system during spring months. A connection between the differences in reanalysis/model surface albedo representation and the albedo observed by satellite is discussed. These results suggest that shortwave radiation should not be overlooked as a significant contributing mechanism to springtime Arctic atmospheric preconditioning.

  6. Time course of neuroprotection induced by in vivo normobaric hyperoxia preconditioning and angiogenesis factors

    Directory of Open Access Journals (Sweden)

    Meisam Shahhoseini

    2017-01-01

    Full Text Available Objective(s:Every year, a large number of people lose their lives due to stroke. Stroke is the second leading cause of death worldwide. Surprisingly, recent studies have shown that preconditioning with hyperoxia (HO increases tissue tolerance to ischemia, ultimately reducing damages caused by stroke. Addressed in this study are beneficial contributions from HO preconditioning into reduced harm to be incurred by the attack, as well as its effect on the expression levels of vascular endothelial growth factor (VEGF and endostatin. Materials and Methods: A set of experiments was conducted where a number of rats were divided into three groups. The animals in the first group received 90% oxygen for 4 hr a day, for 6 days. The second group was housed in room air and the third group was a sham (surgical stress. After 60 min of ischemia, 24 hr blood flow, neurological deficit score (NDS and infarct volume (IV in the group MCAO (Middle Cerebral Artery Occlusion were investigated. Immediately following a 48 hr HO pre-treatment, sampling was performed to measure the expression levels of VEGF and endostatin. Results: Preconditioning with alternating HO led to reduced infarct volume and NDS. Moreover, pre-treatment with HO resulted in increased VEGF expression while decreasing endostatin. Conclusion: Although further studies are deemed necessary to clarify the mechanisms of ischemic tolerance, apparently, somewhat intermittent hyperoxia can be associated with positive impacts by increasing VEGF and decreasing expression of endostatin.

  7. Material pre-conditioning effects on the creep behaviour of 316H stainless steel

    International Nuclear Information System (INIS)

    Mehmanparast, A.; Davies, C.M.; Dean, D.W.; Nikbin, K.

    2013-01-01

    Material pre-conditioning by, for example, pre-strain through component bending and welding is known to alter the creep deformation and creep crack growth (CCG) behaviour of 316H stainless steel. Experimental test data on the creep deformation and crack growth behaviour of 316H weldment compact tension specimens at 550 °C, where the starter defect was introduced into the heat affected zone (HAZ), have been compared to those of obtained from similar specimens manufactured from parent material, which had been subjected to 8% compressive plastic pre-strain at room temperature. Similar degrees of accelerated cracking behaviour compared to parent material, for given values of C*, were exhibited in both 316H HAZ and pre-compressed parent materials. This acceleration has been attributed to the influence of material hardening effects and the reduction of creep ductility in the pre-conditioned materials. These results are discussed in terms of the potential for using material pre-conditioning to assist in predicting the long term cracking behaviour of high temperature 316H stainless steel plant components from shorter term laboratory CCG tests

  8. Efficient CUDA Polynomial Preconditioned Conjugate Gradient Solver for Finite Element Computation of Elasticity Problems

    Directory of Open Access Journals (Sweden)

    Jianfei Zhang

    2013-01-01

    Full Text Available Graphics processing unit (GPU has obtained great success in scientific computations for its tremendous computational horsepower and very high memory bandwidth. This paper discusses the efficient way to implement polynomial preconditioned conjugate gradient solver for the finite element computation of elasticity on NVIDIA GPUs using compute unified device architecture (CUDA. Sliced block ELLPACK (SBELL format is introduced to store sparse matrix arising from finite element discretization of elasticity with fewer padding zeros than traditional ELLPACK-based formats. Polynomial preconditioning methods have been investigated both in convergence and running time. From the overall performance, the least-squares (L-S polynomial method is chosen as a preconditioner in PCG solver to finite element equations derived from elasticity for its best results on different example meshes. In the PCG solver, mixed precision algorithm is used not only to reduce the overall computational, storage requirements and bandwidth but to make full use of the capacity of the GPU devices. With SBELL format and mixed precision algorithm, the GPU-based L-S preconditioned CG can get a speedup of about 7–9 to CPU-implementation.

  9. Regulated production of free radicals by the mitochondrial electron transport chain: Cardiac ischemic preconditioning.

    Science.gov (United States)

    Matsuzaki, Satoshi; Szweda, Pamela A; Szweda, Luke I; Humphries, Kenneth M

    2009-11-30

    Excessive production of free radicals by mitochondria is associated with, and likely contributes to, the progression of numerous pathological conditions. Nevertheless, the production of free radicals by the mitochondria may have important biological functions under normal or stressed conditions by activating or modulating redox-sensitive cellular signaling pathways. This raises the intriguing possibility that regulated mitochondrial free radical production occurs via mechanisms that are distinct from pathologies associated with oxidative damage. Indeed, the capacity of mitochondria to produce free radicals in a limited manner may play a role in ischemic preconditioning, the phenomenon whereby short bouts of ischemia protect from subsequent prolonged ischemia and reperfusion. Ischemic preconditioning can thus serve as an important model system for defining regulatory mechanisms that allow for transient, signal-inducing, production of free radicals by mitochondria. Defining how these mechanism(s) occur will provide insight into therapeutic approaches that minimize oxidative damage without altering normal cellular redox biology. The aim of this review is to present and discuss evidence for the regulated production of superoxide by the electron transport chain within the ischemic preconditioning paradigm of redox regulation.

  10. Refined reservoir description to maximize oil recovery

    International Nuclear Information System (INIS)

    Flewitt, W.E.

    1975-01-01

    To assure maximized oil recovery from older pools, reservoir description has been advanced by fully integrating original open-hole logs and the recently introduced interpretive techniques made available through cased-hole wireline saturation logs. A refined reservoir description utilizing normalized original wireline porosity logs has been completed in the Judy Creek Beaverhill Lake ''A'' Pool, a reefal carbonate pool with current potential productivity of 100,000 BOPD and 188 active wells. Continuous porosity was documented within a reef rim and cap while discontinuous porous lenses characterized an interior lagoon. With the use of pulsed neutron logs and production data a separate water front and pressure response was recognized within discrete environmental units. The refined reservoir description aided in reservoir simulation model studies and quantifying pool performance. A pattern water flood has now replaced the original peripheral bottom water drive to maximize oil recovery

  11. Maximal frustration as an immunological principle.

    Science.gov (United States)

    de Abreu, F Vistulo; Mostardinha, P

    2009-03-06

    A fundamental problem in immunology is that of understanding how the immune system selects promptly which cells to kill without harming the body. This problem poses an apparent paradox. Strong reactivity against pathogens seems incompatible with perfect tolerance towards self. We propose a different view on cellular reactivity to overcome this paradox: effector functions should be seen as the outcome of cellular decisions which can be in conflict with other cells' decisions. We argue that if cellular systems are frustrated, then extensive cross-reactivity among the elements in the system can decrease the reactivity of the system as a whole and induce perfect tolerance. Using numerical and mathematical analyses, we discuss two simple models that perform optimal pathogenic detection with no autoimmunity if cells are maximally frustrated. This study strongly suggests that a principle of maximal frustration could be used to build artificial immune systems. It would be interesting to test this principle in the real adaptive immune system.

  12. Derivative pricing based on local utility maximization

    OpenAIRE

    Jan Kallsen

    2002-01-01

    This paper discusses a new approach to contingent claim valuation in general incomplete market models. We determine the neutral derivative price which occurs if investors maximize their local utility and if derivative demand and supply are balanced. We also introduce the sensitivity process of a contingent claim. This process quantifies the reliability of the neutral derivative price and it can be used to construct price bounds. Moreover, it allows to calibrate market models in order to be co...

  13. Control of Shareholders’ Wealth Maximization in Nigeria

    OpenAIRE

    A. O. Oladipupo; C. O. Okafor

    2014-01-01

    This research focuses on who controls shareholder’s wealth maximization and how does this affect firm’s performance in publicly quoted non-financial companies in Nigeria. The shareholder fund was the dependent while explanatory variables were firm size (proxied by log of turnover), retained earning (representing management control) and dividend payment (representing measure of shareholders control). The data used for this study were obtained from the Nigerian Stock Exchange [NSE] fact book an...

  14. Definable maximal discrete sets in forcing extensions

    DEFF Research Database (Denmark)

    Törnquist, Asger Dag; Schrittesser, David

    2018-01-01

    Let  be a Σ11 binary relation, and recall that a set A is -discrete if no two elements of A are related by . We show that in the Sacks and Miller forcing extensions of L there is a Δ12 maximal -discrete set. We use this to answer in the negative the main question posed in [5] by showing...

  15. Dynamic Convex Duality in Constrained Utility Maximization

    OpenAIRE

    Li, Yusong; Zheng, Harry

    2016-01-01

    In this paper, we study a constrained utility maximization problem following the convex duality approach. After formulating the primal and dual problems, we construct the necessary and sufficient conditions for both the primal and dual problems in terms of FBSDEs plus additional conditions. Such formulation then allows us to explicitly characterize the primal optimal control as a function of the adjoint process coming from the dual FBSDEs in a dynamic fashion and vice versa. Moreover, we also...

  16. Single maximal versus combination punch kinematics.

    Science.gov (United States)

    Piorkowski, Barry A; Lees, Adrian; Barton, Gabor J

    2011-03-01

    The aim of this study was to determine the influence of punch type (Jab, Cross, Lead Hook and Reverse Hook) and punch modality (Single maximal, 'In-synch' and 'Out of synch' combination) on punch speed and delivery time. Ten competition-standard volunteers performed punches with markers placed on their anatomical landmarks for 3D motion capture with an eight-camera optoelectronic system. Speed and duration between key moments were computed. There were significant differences in contact speed between punch types (F(2,18,84.87) = 105.76, p = 0.001) with Lead and Reverse Hooks developing greater speed than Jab and Cross. There were significant differences in contact speed between punch modalities (F(2,64,102.87) = 23.52, p = 0.001) with the Single maximal (M+/- SD: 9.26 +/- 2.09 m/s) higher than 'Out of synch' (7.49 +/- 2.32 m/s), 'In-synch' left (8.01 +/- 2.35 m/s) or right lead (7.97 +/- 2.53 m/s). Delivery times were significantly lower for Jab and Cross than Hook. Times were significantly lower 'In-synch' than a Single maximal or 'Out of synch' combination mode. It is concluded that a defender may have more evasion-time than previously reported. This research could be of use to performers and coaches when considering training preparations.

  17. Formation Control for the MAXIM Mission

    Science.gov (United States)

    Luquette, Richard J.; Leitner, Jesse; Gendreau, Keith; Sanner, Robert M.

    2004-01-01

    Over the next twenty years, a wave of change is occurring in the space-based scientific remote sensing community. While the fundamental limits in the spatial and angular resolution achievable in spacecraft have been reached, based on today s technology, an expansive new technology base has appeared over the past decade in the area of Distributed Space Systems (DSS). A key subset of the DSS technology area is that which covers precision formation flying of space vehicles. Through precision formation flying, the baselines, previously defined by the largest monolithic structure which could fit in the largest launch vehicle fairing, are now virtually unlimited. Several missions including the Micro-Arcsecond X-ray Imaging Mission (MAXIM), and the Stellar Imager will drive the formation flying challenges to achieve unprecedented baselines for high resolution, extended-scene, interferometry in the ultraviolet and X-ray regimes. This paper focuses on establishing the feasibility for the formation control of the MAXIM mission. MAXIM formation flying requirements are on the order of microns, while Stellar Imager mission requirements are on the order of nanometers. This paper specifically addresses: (1) high-level science requirements for these missions and how they evolve into engineering requirements; and (2) the development of linearized equations of relative motion for a formation operating in an n-body gravitational field. Linearized equations of motion provide the ground work for linear formation control designs.

  18. Gradient Dynamics and Entropy Production Maximization

    Science.gov (United States)

    Janečka, Adam; Pavelka, Michal

    2018-01-01

    We compare two methods for modeling dissipative processes, namely gradient dynamics and entropy production maximization. Both methods require similar physical inputs-how energy (or entropy) is stored and how it is dissipated. Gradient dynamics describes irreversible evolution by means of dissipation potential and entropy, it automatically satisfies Onsager reciprocal relations as well as their nonlinear generalization (Maxwell-Onsager relations), and it has statistical interpretation. Entropy production maximization is based on knowledge of free energy (or another thermodynamic potential) and entropy production. It also leads to the linear Onsager reciprocal relations and it has proven successful in thermodynamics of complex materials. Both methods are thermodynamically sound as they ensure approach to equilibrium, and we compare them and discuss their advantages and shortcomings. In particular, conditions under which the two approaches coincide and are capable of providing the same constitutive relations are identified. Besides, a commonly used but not often mentioned step in the entropy production maximization is pinpointed and the condition of incompressibility is incorporated into gradient dynamics.

  19. Maximizing Team Performance: The Critical Role of the Nurse Leader.

    Science.gov (United States)

    Manges, Kirstin; Scott-Cawiezell, Jill; Ward, Marcia M

    2017-01-01

    Facilitating team development is challenging, yet critical for ongoing improvement across healthcare settings. The purpose of this exemplary case study is to examine the role of nurse leaders in facilitating the development of a high-performing Change Team in implementing a patient safety initiative (TeamSTEPPs) using the Tuckman Model of Group Development as a guiding framework. The case study is the synthesis of 2.5 years of critical access hospital key informant interviews (n = 50). Critical juncture points related to team development and key nurse leader actions are analyzed, suggesting that nurse leaders are essential to maximize clinical teams' performance. © 2016 Wiley Periodicals, Inc.

  20. Economic strategies to maximize profits from satellite field developments

    International Nuclear Information System (INIS)

    Antia, D.D.J.

    1994-01-01

    The main strategies that can be used to maximize profits from integrated satellite field developments are: (1) restructuring the cost, production and revenue profile of the satellite field; and (2) increasing the volume of oil/gas processed, and available for future use, by the central processing and distribution facility through: (a) using a combined strategy of low tariffs, volume discount, and netback agreements; (b) using reusable facilities, shared facilities, extended reach wells, contractor finance, partnering agreements, netback agreements, oil/gas price swaps; and (c) improving development, discovery and exploration efficiency

  1. Innovative economy: preconditions and factors of formation and development

    Directory of Open Access Journals (Sweden)

    Alexandru GRIBINCEA

    2017-03-01

    Full Text Available Dynamic economic growth can be considered an important factor in the country’s competitiveness in the market system. In the process of improvement of the market economy model, priority should be given to development of production on a new technical basis, innovation activity to translate scientific and technological research results into production, creation of new technological processes and restructuring in on the modern scientific and technological basis of all branches concerning material production and the service sector. The purpose of the study is to identify the assumptions and factors regarding the formation and development of innovative economy.

  2. Cardiorespiratory Coordination in Repeated Maximal Exercise

    Directory of Open Access Journals (Sweden)

    Sergi Garcia-Retortillo

    2017-06-01

    Full Text Available Increases in cardiorespiratory coordination (CRC after training with no differences in performance and physiological variables have recently been reported using a principal component analysis approach. However, no research has yet evaluated the short-term effects of exercise on CRC. The aim of this study was to delineate the behavior of CRC under different physiological initial conditions produced by repeated maximal exercises. Fifteen participants performed 2 consecutive graded and maximal cycling tests. Test 1 was performed without any previous exercise, and Test 2 6 min after Test 1. Both tests started at 0 W and the workload was increased by 25 W/min in males and 20 W/min in females, until they were not able to maintain the prescribed cycling frequency of 70 rpm for more than 5 consecutive seconds. A principal component (PC analysis of selected cardiovascular and cardiorespiratory variables (expired fraction of O2, expired fraction of CO2, ventilation, systolic blood pressure, diastolic blood pressure, and heart rate was performed to evaluate the CRC defined by the number of PCs in both tests. In order to quantify the degree of coordination, the information entropy was calculated and the eigenvalues of the first PC (PC1 were compared between tests. Although no significant differences were found between the tests with respect to the performed maximal workload (Wmax, maximal oxygen consumption (VO2 max, or ventilatory threshold (VT, an increase in the number of PCs and/or a decrease of eigenvalues of PC1 (t = 2.95; p = 0.01; d = 1.08 was found in Test 2 compared to Test 1. Moreover, entropy was significantly higher (Z = 2.33; p = 0.02; d = 1.43 in the last test. In conclusion, despite the fact that no significant differences were observed in the conventionally explored maximal performance and physiological variables (Wmax, VO2 max, and VT between tests, a reduction of CRC was observed in Test 2. These results emphasize the interest of CRC

  3. Isoflurane Preconditioning Increases Survival of Rat Skin Random-Pattern Flaps by Induction of HIF-1α Expression

    Directory of Open Access Journals (Sweden)

    Yu Sun

    2013-04-01

    isoflurane preconditioning in rats. Conclusions: Isoflurane preconditioning improves survival of skin flaps by up the regulation of HIF-1α expression via Akt-mTOR and Akt-GSK 3β signaling pathways.

  4. Measuring skin necrosis in a randomised controlled feasibility trial of heat preconditioning on wound healing after reconstructive breast surgery: study protocol and statistical analysis plan for the PREHEAT trial.

    Science.gov (United States)

    Cro, Suzie; Mehta, Saahil; Farhadi, Jian; Coomber, Billie; Cornelius, Victoria

    2018-01-01

    Essential strategies are needed to help reduce the number of post-operative complications and associated costs for breast cancer patients undergoing reconstructive breast surgery. Evidence suggests that local heat preconditioning could help improve the provision of this procedure by reducing skin necrosis. Before testing the effectiveness of heat preconditioning in a definitive randomised controlled trial (RCT), we must first establish the best way to measure skin necrosis and estimate the event rate using this definition. PREHEAT is a single-blind randomised controlled feasibility trial comparing local heat preconditioning, using a hot water bottle, against standard care on skin necrosis among breast cancer patients undergoing reconstructive breast surgery. The primary objective of this study is to determine the best way to measure skin necrosis and to estimate the event rate using this definition in each trial arm. Secondary feasibility objectives include estimating recruitment and 30 day follow-up retention rates, levels of compliance with the heating protocol, length of stay in hospital and the rates of surgical versus conservative management of skin necrosis. The information from these objectives will inform the design of a larger definitive effectiveness and cost-effectiveness RCT. This article describes the PREHEAT trial protocol and detailed statistical analysis plan, which includes the pre-specified criteria and process for establishing the best way to measure necrosis. This study will provide the evidence needed to establish the best way to measure skin necrosis, to use as the primary outcome in a future RCT to definitively test the effectiveness of local heat preconditioning. The pre-specified statistical analysis plan, developed prior to unblinded data extraction, sets out the analysis strategy and a comparative framework to support a committee evaluation of skin necrosis measurements. It will increase the transparency of the data analysis for the

  5. Preconditioning results in S-nitrosylation of proteins involved in regulation of mitochondrial energetics and calcium transport.

    Science.gov (United States)

    Sun, Junhui; Morgan, Meghan; Shen, Rong-Fong; Steenbergen, Charles; Murphy, Elizabeth

    2007-11-26

    Nitric oxide has been shown to be an important signaling messenger in ischemic preconditioning (IPC). Accordingly, we investigated whether protein S-nitrosylation occurs in IPC hearts and whether S-nitrosoglutathione (GSNO) elicits similar effects on S-nitrosylation and cardioprotection. Preceding 20 minutes of no-flow ischemia and reperfusion, hearts from C57BL/6J mice were perfused in the Langendorff mode and subjected to the following conditions: (1) control perfusion; (2) IPC; or (3) 0.1 mmol/L GSNO treatment. Compared with control, IPC and GSNO significantly improved postischemic recovery of left ventricular developed pressure and reduced infarct size. IPC and GSNO both significantly increased S-nitrosothiol contents and S-nitrosylation levels of the L-type Ca2+ channel alpha1 subunit in heart membrane fractions. We identified several candidate S-nitrosylated proteins by proteomic analysis following the biotin switch method, including the cardiac sarcoplasmic reticulum Ca2+-ATPase, alpha-ketoglutarate dehydrogenase, and the mitochondrial F1-ATPase alpha1 subunit. The activities of these enzymes were altered in a concentration-dependent manner by GSNO treatment. We further developed a 2D DyLight fluorescence difference gel electrophoresis proteomic method that used DyLight fluors and a modified biotin switch method to identify S-nitrosylated proteins. IPC and GSNO produced a similar pattern of S-nitrosylation modification and cardiac protection against ischemia/reperfusion injury, suggesting that protein S-nitrosylation may play an important cardioprotective role in heart.

  6. Morphine Preconditioning Downregulates MicroRNA-134 Expression Against Oxygen-Glucose Deprivation Injuries in Cultured Neurons of Mice.

    Science.gov (United States)

    Meng, Fanjun; Li, Yan; Chi, Wenying; Li, Junfa

    2016-07-01

    Brain protection by narcotics such as morphine is clinically relevant due to the extensive use of narcotics in the perioperative period. Morphine preconditioning induces neuroprotection in neurons, but it remains uncertain whether microRNA-134 (miR-134) is involved in morphine preconditioning against oxygen-glucose deprivation-induced injuries in primary cortical neurons of mice. The present study examined this issue. After cortical neurons of mice were cultured in vitro for 6 days, the neurons were transfected by respective virus vector, such as lentiviral vector (LV)-miR-control-GFP, LV-pre-miR-134-GFP, LV-pre-miR-134-inhibitor-GFP for 24 hours; after being normally cultured for 3 days again, morphine preconditioning was performed by incubating the transfected primary neurons with morphine (3 μM) for 1 hour, and then neuronal cells were exposed to oxygen-glucose deprivation (OGD) for 1 hour and oxygen-glucose recovery for 12 hours. The neuronal cells survival rate and the amount of apoptotic neurons were determined by MTT assay or TUNEL staining at designated time; and the expression levels of miR-134 were detected using real-time reverse transcription polymerase chain reaction at the same time. The neuronal cell survival rate was significantly higher, and the amount of apoptotic neurons was significantly decreased in neurons preconditioned with morphine before OGD than that of OGD alone. The neuroprotection induced by morphine preconditioning was partially blocked by upregulating miR-134 expression, and was enhanced by downregulating miR-134 expression. The expression of miR-134 was significantly decreased in morphine-preconditioned neurons alone without transfection. By downregulating miR-134 expression, morphine preconditioning protects primary cortical neurons of mice against injuries induced by OGD.

  7. Postactivation potentiation biases maximal isometric strength assessment.

    Science.gov (United States)

    Lima, Leonardo Coelho Rabello; Oliveira, Felipe Bruno Dias; Oliveira, Thiago Pires; Assumpção, Claudio de Oliveira; Greco, Camila Coelho; Cardozo, Adalgiso Croscato; Denadai, Benedito Sérgio

    2014-01-01

    Postactivation potentiation (PAP) is known to enhance force production. Maximal isometric strength assessment protocols usually consist of two or more maximal voluntary isometric contractions (MVCs). The objective of this study was to determine if PAP would influence isometric strength assessment. Healthy male volunteers (n = 23) performed two five-second MVCs separated by a 180-seconds interval. Changes in isometric peak torque (IPT), time to achieve it (tPTI), contractile impulse (CI), root mean square of the electromyographic signal during PTI (RMS), and rate of torque development (RTD), in different intervals, were measured. Significant increases in IPT (240.6 ± 55.7 N·m versus 248.9 ± 55.1 N·m), RTD (746 ± 152 N·m·s(-1) versus 727 ± 158 N·m·s(-1)), and RMS (59.1 ± 12.2% RMSMAX  versus 54.8 ± 9.4% RMSMAX) were found on the second MVC. tPTI decreased significantly on the second MVC (2373 ± 1200 ms versus 2784 ± 1226 ms). We conclude that a first MVC leads to PAP that elicits significant enhancements in strength-related variables of a second MVC performed 180 seconds later. If disconsidered, this phenomenon might bias maximal isometric strength assessment, overestimating some of these variables.

  8. Gain maximization in a probabilistic entanglement protocol

    Science.gov (United States)

    di Lorenzo, Antonio; Esteves de Queiroz, Johnny Hebert

    Entanglement is a resource. We can therefore define gain as a monotonic function of entanglement G (E) . If a pair with entanglement E is produced with probability P, the net gain is N = PG (E) - (1 - P) C , where C is the cost of a failed attempt. We study a protocol where a pair of quantum systems is produced in a maximally entangled state ρm with probability Pm, while it is produced in a partially entangled state ρp with the complementary probability 1 -Pm . We mix a fraction w of the partially entangled pairs with the maximally entangled ones, i.e. we take the state to be ρ = (ρm + wUlocρpUloc+) / (1 + w) , where Uloc is an appropriate unitary local operation designed to maximize the entanglement of ρ. This procedure on one hand reduces the entanglement E, and hence the gain, but on the other hand it increases the probability of success to P =Pm + w (1 -Pm) , therefore the net gain N may increase. There may be hence, a priori, an optimal value for w, the fraction of failed attempts that we mix in. We show that, in the hypothesis of a linear gain G (E) = E , even assuming a vanishing cost C -> 0 , the net gain N is increasing with w, therefore the best strategy is to always mix the partially entangled states. Work supported by CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico, proc. 311288/2014-6, and by FAPEMIG, Fundação de Amparo à Pesquisa de Minas Gerais, proc. IC-FAPEMIG2016-0269 and PPM-00607-16.

  9. Refined isogeometric analysis for a preconditioned conjugate gradient solver

    KAUST Repository

    Garcia, Daniel

    2018-02-12

    Starting from a highly continuous Isogeometric Analysis (IGA) discretization, refined Isogeometric Analysis (rIGA) introduces C0 hyperplanes that act as separators for the direct LU factorization solver. As a result, the total computational cost required to solve the corresponding system of equations using a direct LU factorization solver dramatically reduces (up to a factor of 55) Garcia et al. (2017). At the same time, rIGA enriches the IGA spaces, thus improving the best approximation error. In this work, we extend the complexity analysis of rIGA to the case of iterative solvers. We build an iterative solver as follows: we first construct the Schur complements using a direct solver over small subdomains (macro-elements). We then assemble those Schur complements into a global skeleton system. Subsequently, we solve this system iteratively using Conjugate Gradients (CG) with an incomplete LU (ILU) preconditioner. For a 2D Poisson model problem with a structured mesh and a uniform polynomial degree of approximation, rIGA achieves moderate savings with respect to IGA in terms of the number of Floating Point Operations (FLOPs) and computational time (in seconds) required to solve the resulting system of linear equations. For instance, for a mesh with four million elements and polynomial degree p=3, the iterative solver is approximately 2.6 times faster (in time) when applied to the rIGA system than to the IGA one. These savings occur because the skeleton rIGA system contains fewer non-zero entries than the IGA one. The opposite situation occurs for 3D problems, and as a result, 3D rIGA discretizations provide no gains with respect to their IGA counterparts when considering iterative solvers.

  10. Maximizing percentage depletion in solid minerals

    International Nuclear Information System (INIS)

    Tripp, J.; Grove, H.D.; McGrath, M.

    1982-01-01

    This article develops a strategy for maximizing percentage depletion deductions when extracting uranium or other solid minerals. The goal is to avoid losing percentage depletion deductions by staying below the 50% limitation on taxable income from the property. The article is divided into two major sections. The first section is comprised of depletion calculations that illustrate the problem and corresponding solutions. The last section deals with the feasibility of applying the strategy and complying with the Internal Revenue Code and appropriate regulations. Three separate strategies or appropriate situations are developed and illustrated. 13 references, 3 figures, 7 tables

  11. What currency do bumble bees maximize?

    Directory of Open Access Journals (Sweden)

    Nicholas L Charlton

    2010-08-01

    Full Text Available In modelling bumble bee foraging, net rate of energetic intake has been suggested as the appropriate currency. The foraging behaviour of honey bees is better predicted by using efficiency, the ratio of energetic gain to expenditure, as the currency. We re-analyse several studies of bumble bee foraging and show that efficiency is as good a currency as net rate in terms of predicting behaviour. We suggest that future studies of the foraging of bumble bees should be designed to distinguish between net rate and efficiency maximizing behaviour in an attempt to discover which is the more appropriate currency.

  12. New Maximal Two-distance Sets

    DEFF Research Database (Denmark)

    Lisonek, Petr

    1996-01-01

    A two-distance set in E^d is a point set X inthe d-dimensional Euclidean spacesuch that the distances between distinct points in Xassume only two different non-zero values. Based on results from classical distance geometry, we developan algorithm to classify, for a given dimension, all maximal...... (largest possible)two-distance sets in E^d.Using this algorithm we have completed the full classificationfor all dimensions less than or equal to 7, andwe have found one set in E^8 whosemaximality follows from Blokhuis' upper bound on sizes of s-distance sets.While in the dimensions less than or equal to 6...

  13. Maximizing policy learning in international committees

    DEFF Research Database (Denmark)

    Nedergaard, Peter

    2007-01-01

    , this article demonstrates that valuable lessons can be learned about policy learning, in practice and theoretically, by analysing the cooperation in the OMC committees. Using the Advocacy Coalition Framework as the starting point of analysis, 15 hypotheses on policy learning are tested. Among other things......, it is concluded that in order to maximize policy learning in international committees, empirical data should be made available to committees and provided by sources close to the participants (i.e. the Commission). In addition, the work in the committees should be made prestigious in order to attract well...

  14. Pouliot type duality via a-maximization

    International Nuclear Information System (INIS)

    Kawano, Teruhiko; Ookouchi, Yutaka; Tachikawa, Yuji; Yagi, Futoshi

    2006-01-01

    We study four-dimensional N=1Spin(10) gauge theory with a single spinor and N Q vectors at the superconformal fixed point via the electric-magnetic duality and a-maximization. When gauge invariant chiral primary operators hit the unitarity bounds, we find that the theory with no superpotential is identical to the one with some superpotential at the infrared fixed point. The auxiliary field method in the electric theory offers a satisfying description of the infrared fixed point, which is consistent with the better picture in the magnetic theory. In particular, it gives a clear description of the emergence of new massless degrees of freedom in the electric theory

  15. Maximization techniques for oilfield development profits

    International Nuclear Information System (INIS)

    Lerche, I.

    1999-01-01

    In 1981 Nind provided a quantitative procedure for estimating the optimum number of development wells to emplace on an oilfield to maximize profit. Nind's treatment assumed that there was a steady selling price, that all wells were placed in production simultaneously, and that each well's production profile was identical and a simple exponential decline with time. This paper lifts these restrictions to allow for price fluctuations, variable with time emplacement of wells, and production rates that are more in line with actual production records than is a simple exponential decline curve. As a consequence, it is possible to design production rate strategies, correlated with price fluctuations, so as to maximize the present-day worth of a field. For price fluctuations that occur on a time-scale rapid compared to inflation rates it is appropriate to have production rates correlate directly with such price fluctuations. The same strategy does not apply for price fluctuations occurring on a time-scale long compared to inflation rates where, for small amplitudes in the price fluctuations, it is best to sell as much product as early as possible to overcome inflation factors, while for large amplitude fluctuations the best strategy is to sell product as early as possible but to do so mainly on price upswings. Examples are provided to show how these generalizations of Nind's (1981) formula change the complexion of oilfield development optimization. (author)

  16. Improving Inversions of the Overlap Operator

    International Nuclear Information System (INIS)

    Krieg, S.; Cundy, N.; Eshof, J. van den; Frommer, A.; Lippert, Th.; Schaefer, K.

    2005-01-01

    We present relaxation and preconditioning techniques which accelerate the inversion of the overlap operator by a factor of four on small lattices, with larger gains as the lattice size increases. These improvements can be used in both propagator calculations and dynamical simulations

  17. An Expectation-Maximization Method for Calibrating Synchronous Machine Models

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Da; Zhou, Ning; Lu, Shuai; Lin, Guang

    2013-07-21

    The accuracy of a power system dynamic model is essential to its secure and efficient operation. Lower confidence in model accuracy usually leads to conservative operation and lowers asset usage. To improve model accuracy, this paper proposes an expectation-maximization (EM) method to calibrate the synchronous machine model using phasor measurement unit (PMU) data. First, an extended Kalman filter (EKF) is applied to estimate the dynamic states using measurement data. Then, the parameters are calculated based on the estimated states using maximum likelihood estimation (MLE) method. The EM method iterates over the preceding two steps to improve estimation accuracy. The proposed EM method’s performance is evaluated using a single-machine infinite bus system and compared with a method where both state and parameters are estimated using an EKF method. Sensitivity studies of the parameter calibration using EM method are also presented to show the robustness of the proposed method for different levels of measurement noise and initial parameter uncertainty.

  18. CpG preconditioning regulates miRNA expression that modulates genomic reprogramming associated with neuroprotection against ischemic injury

    Science.gov (United States)

    Vartanian, Keri B; Mitchell, Hugh D; Stevens, Susan L; Conrad, Valerie K; McDermott, Jason E; Stenzel-Poore, Mary P

    2015-01-01

    Cytosine-phosphate-guanine (CpG) preconditioning reprograms the genomic response to stroke to protect the brain against ischemic injury. The mechanisms underlying genomic reprogramming are incompletely understood. MicroRNAs (miRNAs) regulate gene expression; however, their role in modulating gene responses produced by CpG preconditioning is unknown. We evaluated brain miRNA expression in response to CpG preconditioning before and after stroke using microarray. Importantly, we have data from previous gene microarrays under the same conditions, which allowed integration of miRNA and gene expression data to specifically identify regulated miRNA gene targets. CpG preconditioning did not significantly alter miRNA expression before stroke, indicating that miRNA regulation is not critical for the initiation of preconditioning-induced neuroprotection. However, after stroke, differentially regulated miRNAs between CpG- and saline-treated animals associated with the upregulation of several neuroprotective genes, implicating these miRNAs in genomic reprogramming that increases neuroprotection. Statistical analysis revealed that the miRNA targets were enriched in the gene population regulated in the setting of stroke, implying that miRNAs likely orchestrate this gene expression. These data suggest that miRNAs regulate endogenous responses to stroke and that manipulation of these miRNAs may have the potential to acutely activate novel neuroprotective processes that reduce damage. PMID:25388675

  19. Neuroprotection by hypoxic preconditioning involves upregulation of hypoxia-inducible factor-1 in a prenatal model of acute hypoxia.

    Science.gov (United States)

    Giusti, Sebastián; Fiszer de Plazas, Sara

    2012-02-01

    The molecular pathways underlying the neuroprotective effects of preconditioning are promising, potentially drugable targets to promote cell survival. However, these pathways are complex and are not yet fully understood. In this study we have established a paradigm of hypoxic preconditioning based on a chick embryo model of normobaric acute hypoxia previously developed by our group. With this model, we analyzed the role of hypoxia-inducible factor-1α (HIF-1α) stabilization during preconditioning in HIF-1 signaling after the hypoxic injury and in the development of a neuroprotective effect against the insult. To this end, we used a pharmacological approach, based on the in vivo administration of positive (Fe(2+), ascorbate) and negative (CoCl(2)) modulators of the activity of HIF-prolyl hydroxylases (PHDs), the main regulators of HIF-1. We have found that preconditioning has a reinforcing effect on HIF-1 accumulation during the subsequent hypoxic injury. In addition, we have also demonstrated that HIF-1 induction during hypoxic preconditioning is necessary to obtain an enhancement in HIF-1 accumulation and to develop a tolerance against a subsequent hypoxic injury. We provide in vivo evidence that administration of Fe(2+) and ascorbate modulates HIF accumulation, suggesting that PHDs might be targets for neuroprotection in the CNS. Copyright © 2011 Wiley Periodicals, Inc.

  20. The peptide NDP-MSH induces phenotype changes in the heart that resemble ischemic preconditioning.

    Science.gov (United States)

    Catania, Anna; Lonati, Caterina; Sordi, Andrea; Leonardi, Patrizia; Carlin, Andrea; Gatti, Stefano

    2010-01-01

    alpha-Melanocyte-stimulating hormone (alpha-MSH) is a pro-opiomelanocortin (POMC)-derived peptide that exerts multiple protective effects on host cells. Previous investigations showed that treatment with alpha-MSH or synthetic melanocortin agonists reduces heart damage in reperfusion injury and transplantation. The aim of this preclinical research was to determine whether melanocortin treatment induces preconditioning-like cardioprotection. In particular, the plan was to assess whether melanocortin administration causes phenotype changes similar to those induced by repetitive ischemic events. The idea was conceived because both ischemic preconditioning and melanocortin signaling largely depend on cAMP response element binding protein (CREB) phosphorylation. Rats received single i.v. injections of 750microg/kg of the alpha-MSH analogue Nle(4),DPhe(7)-alpha-MSH (NDP-MSH) or saline and were sacrificed at 0.5, 1, 3, or 5h. Western blot analysis showed that rat hearts expressed melanocortin 1 receptor (MC1R) protein. Treatment with NDP-MSH was associated with early and marked increase in interleukin 6 (IL-6) mRNA. This was followed by signal transducer and activator of transcription 3 (STAT3) phosphorylation and induction of suppressor of cytokine signaling 3 (SOCS3). There were no changes in expression of other cytokines of the IL-6 family. Expression of IL-10, IL-1beta, and TNF-alpha was likewise unaltered. In hearts of rats treated with NDP-MSH there was increased expression of the orphan nuclear receptor Nur77. The data indicate that NDP-MSH induces phenotype changes that closely resemble ischemic preconditioning and likely contribute to its established protection against reperfusion injury. In addition, the increased expression of Nur77 and SOCS3 could be part of a broader anti-inflammatory effect.

  1. Preconditioned conjugate-gradient methods for low-speed flow calculations

    Science.gov (United States)

    Ajmani, Kumud; Ng, Wing-Fai; Liou, Meng-Sing

    1993-01-01

    An investigation is conducted into the viability of using a generalized Conjugate Gradient-like method as an iterative solver to obtain steady-state solutions of very low-speed fluid flow problems. Low-speed flow at Mach 0.1 over a backward-facing step is chosen as a representative test problem. The unsteady form of the two dimensional, compressible Navier-Stokes equations is integrated in time using discrete time-steps. The Navier-Stokes equations are cast in an implicit, upwind finite-volume, flux split formulation. The new iterative solver is used to solve a linear system of equations at each step of the time-integration. Preconditioning techniques are used with the new solver to enhance the stability and convergence rate of the solver and are found to be critical to the overall success of the solver. A study of various preconditioners reveals that a preconditioner based on the Lower-Upper Successive Symmetric Over-Relaxation iterative scheme is more efficient than a preconditioner based on Incomplete L-U factorizations of the iteration matrix. The performance of the new preconditioned solver is compared with a conventional Line Gauss-Seidel Relaxation (LGSR) solver. Overall speed-up factors of 28 (in terms of global time-steps required to converge to a steady-state solution) and 20 (in terms of total CPU time on one processor of a CRAY-YMP) are found in favor of the new preconditioned solver, when compared with the LGSR solver.

  2. Isometric pre-conditioning blunts exercise-induced muscle damage but does not attenuate changes in running economy following downhill running.

    Science.gov (United States)

    Lima, Leonardo C R; Bassan, Natália M; Cardozo, Adalgiso C; Gonçalves, Mauro; Greco, Camila C; Denadai, Benedito S

    2018-05-08

    Running economy (RE) is impaired following unaccustomed eccentric-biased exercises that induce muscle damage. It is also known that muscle damage is reduced when maximal voluntary isometric contractions (MVIC) are performed at a long muscle length 2-4 days prior to maximal eccentric exercise with the same muscle, a phenomenon that can be described as isometric pre-conditioning (IPC). We tested the hypothesis that IPC could attenuate muscle damage and changes in RE following downhill running. Thirty untrained men were randomly assigned into experimental or control groups and ran downhill on a treadmill (-15%) for 30 min. Participants in the experimental group completed 10 MVIC in a leg press machine two days prior to downhill running, while participants in the control group did not perform IPC. The magnitude of changes in muscle soreness determined 48 h after downhill running was greater for the control group (122 ± 28 mm) than for the experimental group (92 ± 38 mm). Isometric peak torque recovered faster in the experimental group compared with the control group (3 days vs. no full recovery, respectively). No significant effect of IPC was found for countermovement jump height, serum creatine kinase activity or any parameters associated with RE. These results supported the hypothesis that IPC attenuates changes in markers of muscle damage. The hypothesis that IPC attenuates changes in RE was not supported by our data. It appears that the mechanisms involved in changes in markers of muscle damage and parameters associated with RE following downhill running are not completely shared. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Enhanced Local Skeletal Muscle Oxidative Capacity and Microvascular Blood Flow Following 7-Day Ischemic Preconditioning in Healthy Humans

    Directory of Open Access Journals (Sweden)

    Owen Jeffries

    2018-05-01

    Full Text Available Ischemic preconditioning (IPC, which involves intermittent periods of ischemia followed by reperfusion, is an effective clinical intervention that reduces the risk of myocardial injury and confers ischemic tolerance to skeletal muscle. Repeated bouts of IPC have been shown to stimulate long-term changes vascular function, however, it is unclear what metabolic adaptations may occur locally in the muscle. Therefore, we investigated 7 days of bilateral lower limb IPC (4 × 5 min above limb occlusion pressure (220 mmHg; n = 10, or sham (20 mmHg; n = 10, on local muscle oxidative capacity and microvascular blood flow. Oxidative capacity was measured using near-infrared spectroscopy (NIRS during repeated short duration arterial occlusions (300 mmHg. Microvascular blood flow was assessed during the recovery from submaximal isometric plantar flexion exercises at 40 and 60% of maximal voluntary contraction (MVC. Following the intervention period, beyond the late phase of protection (72 h, muscle oxidative recovery kinetics were speeded by 13% (rate constant pre 2.89 ± 0.47 min-1 vs. post 3.32 ± 0.69 min-1; P < 0.05 and resting muscle oxygen consumption (mO2 was reduced by 16.4% (pre 0.39 ± 0.16%.s-1 vs. post 0.33 ± 0.14%.s-1; P < 0.05. During exercise, changes in deoxygenated hemoglobin (HHb from rest to steady state were reduced at 40 and 60% MVC (16 and 12%, respectively, P < 0.05 despite similar measures of total hemoglobin (tHb. At the cessation of exercise, the time constant for recovery in oxygenated hemoglobin (O2Hb was accelerated at 40 and 60% MVC (by 33 and 43%, respectively suggesting enhanced reoxygenation in the muscle. No changes were reported for systemic measures of resting heart rate or blood pressure. In conclusion, repeated bouts of IPC over 7 consecutive days increased skeletal muscle oxidative capacity and microvascular muscle blood flow. These findings are consistent with enhanced mitochondrial and vascular function following

  4. Effect of limb ischemic preconditioning on myocardial apoptosis-related proteins in ischemia-reperfusion injury

    OpenAIRE

    GAO, JIANZHI; ZHAO, LINJING; WANG, YONGLING; TENG, QINGLEI; LIANG, LIDONG; ZHANG, JINYING

    2013-01-01

    The aim of this study was to investigate the effect of limb ischemic preconditioning (LIPC) on myocardial apoptosis in myocardial ischemia-reperfusion injury (MIRI), as well as the regulation of caspase-3 and the B cell lymphoma 2 (Bcl-2) gene in LIPC. A total of 50 rats were divided randomly into 5 groups (n=10). Four rats in each group were drawn out for detection of apoptosis. The sham, MIRI and LIPC groups underwent surgery without additional treatment. In the LY294002 group, LY294002 pre...

  5. Media-Competence as Precondition of the Students’ Intercultural Competence Formation of the Danube Region

    Directory of Open Access Journals (Sweden)

    Anastasia Hrekova

    2015-08-01

    Full Text Available The unity of Europe, including countries of the Danube region, takes into account a variety of national cultures. One of the priority tasks of European society development is the mutual enrichment of intellectual values and at the same time national identity preservation. The article deals with the role of media-education of the effective cooperation development of ethnic cultures. Media literacy is analyzed as a precondition for the formation of intercultural competence of student youth from the Lower Danube Region. The mechanisms of adequate perception formation of cultural differences through the students’ media-competence education of the Danube region are under analysis.

  6. Efficient augmented Lagrangian-type preconditioning for the Oseen problem using Grad-Div stabilization

    KAUST Repository

    Heister, Timo

    2012-01-29

    Efficient preconditioning for Oseen-type problems is an active research topic. We present a novel approach leveraging stabilization for inf-sup stable discretizations. The Grad-Div stabilization shares the algebraic properties with an augmented Lagrangian-type term. Both simplify the approximation of the Schur complement, especially in the convection-dominated case. We exploit this for the construction of the preconditioner. Solving the discretized Oseen problem with an iterative Krylov-type method shows that the outer iteration numbers are retained independent of mesh size, viscosity, and finite element order. Thus, the preconditioner is very competitive. © 2012 John Wiley & Sons, Ltd.

  7. Efficient augmented Lagrangian-type preconditioning for the Oseen problem using Grad-Div stabilization

    KAUST Repository

    Heister, Timo; Rapin, Gerd

    2012-01-01

    Efficient preconditioning for Oseen-type problems is an active research topic. We present a novel approach leveraging stabilization for inf-sup stable discretizations. The Grad-Div stabilization shares the algebraic properties with an augmented Lagrangian-type term. Both simplify the approximation of the Schur complement, especially in the convection-dominated case. We exploit this for the construction of the preconditioner. Solving the discretized Oseen problem with an iterative Krylov-type method shows that the outer iteration numbers are retained independent of mesh size, viscosity, and finite element order. Thus, the preconditioner is very competitive. © 2012 John Wiley & Sons, Ltd.

  8. Remote ischemic preconditioning does not increase circulating or effector organ concentrations of proopiomelanocortin derivates

    DEFF Research Database (Denmark)

    Birkelund, Thomas; Obad, Damir; Matejec, Reginald

    2015-01-01

    Objectives. The aim of the present study was to compare changes in circulating levels of proopiomelanocortin (POMC) derivates and lactate after remote ischemic preconditioning (IPC) and physical exercise. Introduction. Remote IPC (rIPC) is cardioprotective following acute myocardial infarction....... Results. While rIPC was not associated with any significant increase in circulating POMC derivates or lactate, exercise induced significant elevation of both compared with baseline. Conclusions. We were not able to demonstrate a detectable increase in circulating POMC derivates by a standard rIPC stimulus...

  9. Effect of Preconditioning with Desflurane on Phosphorylated Glycogen Synthase Kinase 3β Contents in an Experiment

    OpenAIRE

    V. V. Likhvantsev; O. A. Grebenchikov; R. A. Cherpakov; Yu. V. Skripkin; K. Yu. Borisov

    2016-01-01

    The purpose of this study is to determine and evaluate if the preconditioning with desflurane depends on level of phosphoGSK3β.Material and methods. White outbred male rats (56) were randomly allocated to 6 groups. Ischemia/reperfusion modeling was performed using V. G.Korpachev's technique. The reference group consisted of sham (falselyoperated) animals. The second group underwent global ischemia/reperfusion after anesthesia with chloral hydrate. The next two groups were treated with either ...

  10. Multigrid preconditioned conjugate-gradient method for large-scale wave-front reconstruction.

    Science.gov (United States)

    Gilles, Luc; Vogel, Curtis R; Ellerbroek, Brent L

    2002-09-01

    We introduce a multigrid preconditioned conjugate-gradient (MGCG) iterative scheme for computing open-loop wave-front reconstructors for extreme adaptive optics systems. We present numerical simulations for a 17-m class telescope with n = 48756 sensor measurement grid points within the aperture, which indicate that our MGCG method has a rapid convergence rate for a wide range of subaperture average slope measurement signal-to-noise ratios. The total computational cost is of order n log n. Hence our scheme provides for fast wave-front simulation and control in large-scale adaptive optics systems.

  11. PO-62 - Remote ischemic preconditioning in head and neck cancer reconstruction - a randomized controlled trial

    DEFF Research Database (Denmark)

    Krag, A E; Kiil, B J; Hvas, Christine Lodberg

    2016-01-01

    flap anastomoses or microcirculation is the main reason for total flap necrosis with potential fatal consequences for the patient. Remote ischemic preconditioning (RIPC), where brief cycles of upper extremity ischemia are induced with an inflatable tourniquet, triggers a global protection of tissues...... will be included in the trial. The subjects will be randomized to RIPC or sham during surgery. RIPC is administered by four 5-minute cycles of upper extremity ischemia, each separated by five minutes of reperfusion. Blood samples will be drawn preoperatively, before RIPC/sham, 3 hours after RIPC/ sham, 6 hours...... oncologic therapy can be initiated in timely fashion....

  12. Mitochondrial cyclophilin-D as a critical mediator of ischaemic preconditioning

    OpenAIRE

    Hausenloy, Derek J.; Lim, Shiang Y.; Ong, Sang-Ging; Davidson, Sean M.; Yellon, Derek M.

    2010-01-01

    Aims It has been suggested that mitochondrial reactive oxygen species (ROS), Akt and Erk1/2 and more recently the mitochondrial permeability transition pore (mPTP) may act as mediators of ischaemic preconditioning (IPC), although the actual interplay between these mediators is unclear. The aim of the present study is to determine whether the cyclophilin-D (CYPD) component of the mPTP is required by IPC to generate mitochondrial ROS and subsequently activate Akt and Erk1/2. Methods and results...

  13. Shareholder, stakeholder-owner or broad stakeholder maximization

    DEFF Research Database (Denmark)

    Mygind, Niels

    2004-01-01

    With reference to the discussion about shareholder versus stakeholder maximization it is argued that the normal type of maximization is in fact stakeholder-owner maxi-mization. This means maximization of the sum of the value of the shares and stake-holder benefits belonging to the dominating...... including the shareholders of a company. Although it may be the ultimate goal for Corporate Social Responsibility to achieve this kind of maximization, broad stakeholder maximization is quite difficult to give a precise definition. There is no one-dimensional measure to add different stakeholder benefits...... not traded on the mar-ket, and therefore there is no possibility for practical application. Broad stakeholder maximization instead in practical applications becomes satisfying certain stakeholder demands, so that the practical application will be stakeholder-owner maximization un-der constraints defined...

  14. Maximizing Lumen Gain With Directional Atherectomy.

    Science.gov (United States)

    Stanley, Gregory A; Winscott, John G

    2016-08-01

    To describe the use of a low-pressure balloon inflation (LPBI) technique to delineate intraluminal plaque and guide directional atherectomy in order to maximize lumen gain and achieve procedure success. The technique is illustrated in a 77-year-old man with claudication who underwent superficial femoral artery revascularization using a HawkOne directional atherectomy catheter. A standard angioplasty balloon was inflated to 1 to 2 atm during live fluoroscopy to create a 3-dimensional "lumenogram" of the target lesion. Directional atherectomy was performed only where plaque impinged on the balloon at a specific fluoroscopic orientation. The results of the LPBI technique were corroborated with multimodality diagnostic imaging, including digital subtraction angiography, intravascular ultrasound, and intra-arterial pressure measurements. With the LPBI technique, directional atherectomy can routinely achieve <10% residual stenosis, as illustrated in this case, thereby broadly supporting a no-stent approach to lower extremity endovascular revascularization. © The Author(s) 2016.

  15. Primordial two-component maximally symmetric inflation

    Science.gov (United States)

    Enqvist, K.; Nanopoulos, D. V.; Quirós, M.; Kounnas, C.

    1985-12-01

    We propose a two-component inflation model, based on maximally symmetric supergravity, where the scales of reheating and the inflation potential at the origin are decoupled. This is possible because of the second-order phase transition from SU(5) to SU(3)×SU(2)×U(1) that takes place when φ≅φcinflation at the global minimum, and leads to a reheating temperature TR≅(1015-1016) GeV. This makes it possible to generate baryon asymmetry in the conventional way without any conflict with experimental data on proton lifetime. The mass of the gravitinos is m3/2≅1012 GeV, thus avoiding the gravitino problem. Monopoles are diluted by residual inflation in the broken phase below the cosmological bounds if φcUSA.

  16. Distributed-Memory Fast Maximal Independent Set

    Energy Technology Data Exchange (ETDEWEB)

    Kanewala Appuhamilage, Thejaka Amila J.; Zalewski, Marcin J.; Lumsdaine, Andrew

    2017-09-13

    The Maximal Independent Set (MIS) graph problem arises in many applications such as computer vision, information theory, molecular biology, and process scheduling. The growing scale of MIS problems suggests the use of distributed-memory hardware as a cost-effective approach to providing necessary compute and memory resources. Luby proposed four randomized algorithms to solve the MIS problem. All those algorithms are designed focusing on shared-memory machines and are analyzed using the PRAM model. These algorithms do not have direct efficient distributed-memory implementations. In this paper, we extend two of Luby’s seminal MIS algorithms, “Luby(A)” and “Luby(B),” to distributed-memory execution, and we evaluate their performance. We compare our results with the “Filtered MIS” implementation in the Combinatorial BLAS library for two types of synthetic graph inputs.

  17. Quench dynamics of topological maximally entangled states.

    Science.gov (United States)

    Chung, Ming-Chiang; Jhu, Yi-Hao; Chen, Pochung; Mou, Chung-Yu

    2013-07-17

    We investigate the quench dynamics of the one-particle entanglement spectra (OPES) for systems with topologically nontrivial phases. By using dimerized chains as an example, it is demonstrated that the evolution of OPES for the quenched bipartite systems is governed by an effective Hamiltonian which is characterized by a pseudospin in a time-dependent pseudomagnetic field S(k,t). The existence and evolution of the topological maximally entangled states (tMESs) are determined by the winding number of S(k,t) in the k-space. In particular, the tMESs survive only if nontrivial Berry phases are induced by the winding of S(k,t). In the infinite-time limit the equilibrium OPES can be determined by an effective time-independent pseudomagnetic field Seff(k). Furthermore, when tMESs are unstable, they are destroyed by quasiparticles within a characteristic timescale in proportion to the system size.

  18. Maximizing policy learning in international committees

    DEFF Research Database (Denmark)

    Nedergaard, Peter

    2007-01-01

    , this article demonstrates that valuable lessons can be learned about policy learning, in practice and theoretically, by analysing the cooperation in the OMC committees. Using the Advocacy Coalition Framework as the starting point of analysis, 15 hypotheses on policy learning are tested. Among other things......In the voluminous literature on the European Union's open method of coordination (OMC), no one has hitherto analysed on the basis of scholarly examination the question of what contributes to the learning processes in the OMC committees. On the basis of a questionnaire sent to all participants......, it is concluded that in order to maximize policy learning in international committees, empirical data should be made available to committees and provided by sources close to the participants (i.e. the Commission). In addition, the work in the committees should be made prestigious in order to attract well...

  19. Lovelock black holes with maximally symmetric horizons

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Hideki; Willison, Steven; Ray, Sourya, E-mail: hideki@cecs.cl, E-mail: willison@cecs.cl, E-mail: ray@cecs.cl [Centro de Estudios CientIficos (CECs), Casilla 1469, Valdivia (Chile)

    2011-08-21

    We investigate some properties of n( {>=} 4)-dimensional spacetimes having symmetries corresponding to the isometries of an (n - 2)-dimensional maximally symmetric space in Lovelock gravity under the null or dominant energy condition. The well-posedness of the generalized Misner-Sharp quasi-local mass proposed in the past study is shown. Using this quasi-local mass, we clarify the basic properties of the dynamical black holes defined by a future outer trapping horizon under certain assumptions on the Lovelock coupling constants. The C{sup 2} vacuum solutions are classified into four types: (i) Schwarzschild-Tangherlini-type solution; (ii) Nariai-type solution; (iii) special degenerate vacuum solution; and (iv) exceptional vacuum solution. The conditions for the realization of the last two solutions are clarified. The Schwarzschild-Tangherlini-type solution is studied in detail. We prove the first law of black-hole thermodynamics and present the expressions for the heat capacity and the free energy.

  20. MAXIMIZING THE BENEFITS OF ERP SYSTEMS

    Directory of Open Access Journals (Sweden)

    Paulo André da Conceição Menezes

    2010-04-01

    Full Text Available The ERP (Enterprise Resource Planning systems have been consolidated in companies with different sizes and sectors, allowing their real benefits to be definitively evaluated. In this study, several interactions have been studied in different phases, such as the strategic priorities and strategic planning defined as ERP Strategy; business processes review and the ERP selection in the pre-implementation phase, the project management and ERP adaptation in the implementation phase, as well as the ERP revision and integration efforts in the post-implementation phase. Through rigorous use of case study methodology, this research led to developing and to testing a framework for maximizing the benefits of the ERP systems, and seeks to contribute for the generation of ERP initiatives to optimize their performance.