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Sample records for maximum normal stress

  1. 49 CFR 230.24 - Maximum allowable stress.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Maximum allowable stress. 230.24 Section 230.24... Allowable Stress § 230.24 Maximum allowable stress. (a) Maximum allowable stress value. The maximum allowable stress value on any component of a steam locomotive boiler shall not exceed 1/4 of the ultimate...

  2. Penalized Maximum Likelihood Estimation for univariate normal mixture distributions

    International Nuclear Information System (INIS)

    Ridolfi, A.; Idier, J.

    2001-01-01

    Due to singularities of the likelihood function, the maximum likelihood approach for the estimation of the parameters of normal mixture models is an acknowledged ill posed optimization problem. Ill posedness is solved by penalizing the likelihood function. In the Bayesian framework, it amounts to incorporating an inverted gamma prior in the likelihood function. A penalized version of the EM algorithm is derived, which is still explicit and which intrinsically assures that the estimates are not singular. Numerical evidence of the latter property is put forward with a test

  3. Maximum Solutions of Normalized Ricci Flow on 4-Manifolds

    Science.gov (United States)

    Fang, Fuquan; Zhang, Yuguang; Zhang, Zhenlei

    2008-10-01

    We consider the maximum solution g( t), t ∈ [0, + ∞), to the normalized Ricci flow. Among other things, we prove that, if ( M, ω) is a smooth compact symplectic 4-manifold such that {b_2^+(M) > 1} and let g( t), t ∈ [0, ∞), be a solution to (1.3) on M whose Ricci curvature satisfies that |Ric( g( t))| ≤ 3 and additionally χ( M) = 3τ ( M) > 0, then there exists an {min mathbb{N}} , and a sequence of points { x j, k ∈ M}, j = 1, . . . , m, satisfying that, by passing to a subsequence, {{(M, g(tk+t), x_{1,k},ldots, x_{m,k})stackrel{d_{GH}}longrightarrow ({\\coprod limitsm_{j=1}} N_j , g_{infty}, x_{1,infty}, ldots, x_{m,infty}),}} t ∈ [0, ∞), in the m-pointed Gromov-Hausdorff sense for any sequence t k → ∞, where ( N j , g ∞), j = 1, . . . , m, are complete complex hyperbolic orbifolds of complex dimension 2 with at most finitely many isolated orbifold points. Moreover, the convergence is C ∞ in the non-singular part of {\\coprod _1^m Nj} and {text{Vol}_{g0}(M)=sum_{j=1}mtext{Vol}_{g_{infty}}(Nj)} , where χ( M) (resp. τ( M)) is the Euler characteristic (resp. signature) of M.

  4. Normal Stress or Adjustment Disorder?

    Science.gov (United States)

    ... disorder is a type of stress-related mental illness that can affect your feelings, thoughts and behaviors. Signs and symptoms of an adjustment disorder can include: Anxiety Poor school or work performance Relationship problems Sadness ...

  5. Normal stresses in semiflexible polymer hydrogels

    Science.gov (United States)

    Vahabi, M.; Vos, Bart E.; de Cagny, Henri C. G.; Bonn, Daniel; Koenderink, Gijsje H.; MacKintosh, F. C.

    2018-03-01

    Biopolymer gels such as fibrin and collagen networks are known to develop tensile axial stress when subject to torsion. This negative normal stress is opposite to the classical Poynting effect observed for most elastic solids including synthetic polymer gels, where torsion provokes a positive normal stress. As shown recently, this anomalous behavior in fibrin gels depends on the open, porous network structure of biopolymer gels, which facilitates interstitial fluid flow during shear and can be described by a phenomenological two-fluid model with viscous coupling between network and solvent. Here we extend this model and develop a microscopic model for the individual diagonal components of the stress tensor that determine the axial response of semiflexible polymer hydrogels. This microscopic model predicts that the magnitude of these stress components depends inversely on the characteristic strain for the onset of nonlinear shear stress, which we confirm experimentally by shear rheometry on fibrin gels. Moreover, our model predicts a transient behavior of the normal stress, which is in excellent agreement with the full time-dependent normal stress we measure.

  6. Normal stress Sestamibi study: why re inject?

    International Nuclear Information System (INIS)

    Unger, S.A.; Hughes, T.

    2000-01-01

    Full text: Myocardial perfusion imaging (MPI) is widely used for risk stratification of patients with known or suspected coronary artery disease. A normal MPI study predicts an annual cardiac event rate of 99 Tc m -Sestamibi (MIBI), omitting the rest study when the post-stress study is interpreted as normal. The safety of this approach has not been validated, all published reports utilising both rest and stress images to interpret a study as 'normal'. Between 1/1/98 and 30/8/98, 489 patients (patients) were referred to our department for stress MPI. Of these, 237 were interpreted as normal on the basis of their post-stress study, and did not undergo a rest study. 12 month clinical follow-up was available in 184 (78%) of these patients, representing the study group (82 males, 102 females; mean age 61±12 years). 156 of these patients were referred for assessment of chest pain, three for dyspnoea, six for abnormal ECGs, and 19 for pre-operative evaluation. At one year of follow-up, there were no myocardial infarcts or admissions for unstable angina, and no cardiac deaths. Three patients died of non-cardiac causes. Seven patients underwent coronary angiography: five were normal, one had a single 50% stenosis, and one had an 80% vein graft stenosis which was subsequently angioplastied. In conclusion, a normal stress MIBI image predicts an excellent prognosis and negates the need for a rest reinjection study, thus reducing patient camera time and radiation exposure, improving departmental throughput, and minimising public health expenditure. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

  7. The maximum possible stress intensity factor for a crack in an unknown residual stress field

    International Nuclear Information System (INIS)

    Coules, H.E.; Smith, D.J.

    2015-01-01

    Residual and thermal stress fields in engineering components can act on cracks and structural flaws, promoting or inhibiting fracture. However, these stresses are limited in magnitude by the ability of materials to sustain them elastically. As a consequence, the stress intensity factor which can be applied to a given defect by a self-equilibrating stress field is also limited. We propose a simple weight function method for determining the maximum stress intensity factor which can occur for a given crack or defect in a one-dimensional self-equilibrating stress field, i.e. an upper bound for the residual stress contribution to K I . This can be used for analysing structures containing defects and subject to residual stress without any information about the actual stress field which exists in the structure being analysed. A number of examples are given, including long radial cracks and fully-circumferential cracks in thick-walled hollow cylinders containing self-equilibrating stresses. - Highlights: • An upper limit to the contribution of residual stress to stress intensity factor. • The maximum K I for self-equilibrating stresses in several geometries is calculated. • A weight function method can determine this maximum for 1-dimensional stress fields. • Simple MATLAB scripts for calculating maximum K I provided as supplementary material.

  8. Monodimensional estimation of maximum Reynolds shear stress in the downstream flow field of bileaflet valves.

    Science.gov (United States)

    Grigioni, Mauro; Daniele, Carla; D'Avenio, Giuseppe; Barbaro, Vincenzo

    2002-05-01

    Turbulent flow generated by prosthetic devices at the bloodstream level may cause mechanical stress on blood particles. Measurement of the Reynolds stress tensor and/or some of its components is a mandatory step to evaluate the mechanical load on blood components exerted by fluid stresses, as well as possible consequent blood damage (hemolysis or platelet activation). Because of the three-dimensional nature of turbulence, in general, a three-component anemometer should be used to measure all components of the Reynolds stress tensor, but this is difficult, especially in vivo. The present study aimed to derive the maximum Reynolds shear stress (RSS) in three commercially available prosthetic heart valves (PHVs) of wide diffusion, starting with monodimensional data provided in vivo by echo Doppler. Accurate measurement of PHV flow field was made using laser Doppler anemometry; this provided the principal turbulence quantities (mean velocity, root-mean-square value of velocity fluctuations, average value of cross-product of velocity fluctuations in orthogonal directions) needed to quantify the maximum turbulence-related shear stress. The recorded data enabled determination of the relationship, the Reynolds stresses ratio (RSR) between maximum RSS and Reynolds normal stress in the main flow direction. The RSR was found to be dependent upon the local structure of the flow field. The reported RSR profiles, which permit a simple calculation of maximum RSS, may prove valuable during the post-implantation phase, when an assessment of valve function is made echocardiographically. Hence, the risk of damage to blood constituents associated with bileaflet valve implantation may be accurately quantified in vivo.

  9. EFFECT OF CAFFEINE ON OXIDATIVE STRESS DURING MAXIMUM INCREMENTAL EXERCISE

    Directory of Open Access Journals (Sweden)

    Guillermo J. Olcina

    2006-12-01

    Full Text Available Caffeine (1,3,7-trimethylxanthine is an habitual substance present in a wide variety of beverages and in chocolate-based foods and it is also used as adjuvant in some drugs. The antioxidant ability of caffeine has been reported in contrast with its pro- oxidant effects derived from its action mechanism such as the systemic release of catecholamines. The aim of this work was to evaluate the effect of caffeine on exercise oxidative stress, measuring plasma vitamins A, E, C and malonaldehyde (MDA as markers of non enzymatic antioxidant status and lipid peroxidation respectively. Twenty young males participated in a double blind (caffeine 5mg·kg- 1 body weight or placebo cycling test until exhaustion. In the exercise test, where caffeine was ingested prior to the test, exercise time to exhaustion, maximum heart rate, and oxygen uptake significantly increased, whereas respiratory exchange ratio (RER decreased. Vitamins A and E decreased with exercise and vitamin C and MDA increased after both the caffeine and placebo tests but, regarding these particular variables, there were no significant differences between the two test conditions. The results obtained support the conclusion that this dose of caffeine enhances the ergospirometric response to cycling and has no effect on lipid peroxidation or on the antioxidant vitamins A, E and C

  10. An experimental study on the normal stress of magnetorheological fluids

    International Nuclear Information System (INIS)

    Jiang, Jile; Tian, Yu; Ren, Dongxue; Meng, Yonggang

    2011-01-01

    The dependence of the normal stress on the shear rate and magnetic field strength in the shear flow of magnetorheological (MR) fluids has been studied experimentally. An obvious normal stress could be observed when the applied magnetic field was higher than a critical value. The normal stress increases considerably with increase of the shear rate and magnetic field, and decreases suddenly and significantly upon the onset of shear thickening in MR fluids. The ratio of shear stress to normal stress, an analogue of the friction coefficient, increases with increase of the shear rate, but decreases with increase of the applied magnetic field. Along with the shear stress, the normal stress in MR fluids could provide a more comprehensive understanding of the MR effect, and the evolution of the particle structure in shear flow, and may have important implications for preparing high performance magnetostrictive elastomers with high force output along the magnetic field direction

  11. Dimensions of the prostatic and membranous urethra in normal male dogs during maximum distension retrograde urethrocystography

    International Nuclear Information System (INIS)

    Feeney, D.A.; Johnston, G.R.; Osborne, C.A.; Tomlinson, M.J.

    1984-01-01

    Prostatic and membranous urethral diameter was measured in 24 normal mature male Beagle dogs during maximum distension retrograde urethrocystography. This technique involved retrograde urethral distension by infusion with contrast medium until the urinary bladder was distended and the vesicourethral junction remained opened as observed by fluoroscopy. Lateral and ventro-dorsal radiographs were made during subsequent injections of 5–10 ml of contrast medium. The prostatic urethra was consistently greater in diameter than the membranous urethra. However, the numerical ratio between the prostatic urethral diameter and the membranous urethral diameter varied among these dogs by a factor of 2 at the numerical extremes

  12. Asymptotic Normality of the Maximum Pseudolikelihood Estimator for Fully Visible Boltzmann Machines.

    Science.gov (United States)

    Nguyen, Hien D; Wood, Ian A

    2016-04-01

    Boltzmann machines (BMs) are a class of binary neural networks for which there have been numerous proposed methods of estimation. Recently, it has been shown that in the fully visible case of the BM, the method of maximum pseudolikelihood estimation (MPLE) results in parameter estimates, which are consistent in the probabilistic sense. In this brief, we investigate the properties of MPLE for the fully visible BMs further, and prove that MPLE also yields an asymptotically normal parameter estimator. These results can be used to construct confidence intervals and to test statistical hypotheses. These constructions provide a closed-form alternative to the current methods that require Monte Carlo simulation or resampling. We support our theoretical results by showing that the estimator behaves as expected in simulation studies.

  13. Oxidative stress in normal and diabetic rats.

    Science.gov (United States)

    Torres, M D; Canal, J R; Pérez, C

    1999-01-01

    Parameters related to oxidative stress were studied in a group of 10 Wistar diabetic rats and 10 control rats. The levels of total erythrocyte catalase activity in the diabetic animals were significantly (pC18:2) ratios. Greater vitaminE/triglyceride (TG) ratio, however, appeared in the control group. The corresponding vitamin A ratios (vitaminA/TG, vitaminA/PUFA, vitaminA/C 18:2) were higher in the control group. Our work corroborates the findings that fatty acid metabolism presents alterations in the diabetes syndrome and that the antioxidant status is affected.

  14. Influence of Thread Root Radius on Maximum Local Stresses at Large Diameter Bolts under Axial Loading

    Directory of Open Access Journals (Sweden)

    Cojocaru Vasile

    2014-06-01

    Full Text Available In the thread root area of the threaded bolts submitted to axial loading occur local stresses, higher that nominal stresses calculated for the bolts. These local stresses can generate failure and can reduce the fatigue life of the parts. The paper is focused on the study of the influence of the thread root radius on the maximum local stresses. A large diameter trapezoidal bolt was subjected to a static analysis (axial loading using finite element simulation.

  15. An iterative procedure for obtaining maximum-likelihood estimates of the parameters for a mixture of normal distributions, Addendum

    Science.gov (United States)

    Peters, B. C., Jr.; Walker, H. F.

    1975-01-01

    New results and insights concerning a previously published iterative procedure for obtaining maximum-likelihood estimates of the parameters for a mixture of normal distributions were discussed. It was shown that the procedure converges locally to the consistent maximum likelihood estimate as long as a specified parameter is bounded between two limits. Bound values were given to yield optimal local convergence.

  16. Static and kinetic friction of granite at high normal stress

    Science.gov (United States)

    Byerlee, J.D.

    1970-01-01

    Frictional sliding on ground surfaces of granite, angle of sliding planes 30?? and 45??, was investigated as a function of confining pressure. Over the normal stress range of 2-12 kb, the static frictional shear stress ??s follows the relationship ??s = 0??5 + 0?? ??n and the kinetic frictional shear stress ??k was calculated to be ??k = 0??25 + 0??47 ??n. ?? 1970.

  17. Fatigue life prediction method for contact wire using maximum local stress

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Seok; Haochuang, Li; Seok, Chang Sung; Koo, Jae Mean [Sungkyunkwan University, Suwon (Korea, Republic of); Lee, Ki Won; Kwon, Sam Young; Cho, Yong Hyeon [Korea Railroad Research Institute, Uiwang (Korea, Republic of)

    2015-01-15

    Railway contact wires supplying electricity to trains are exposed to repeated mechanical strain and stress caused by their own weight and discontinuous contact with a pantograph during train operation. Since the speed of railway transportation has increased continuously, railway industries have recently reported a number of contact wire failures caused by mechanical fatigue fractures instead of normal wear, which has been a more common failure mechanism. To secure the safety and durability of contact wires in environments with increased train speeds, a bending fatigue test on contact wire has been performed. The test equipment is too complicated to evaluate the fatigue characteristics of contact wire. Thus, the axial tension fatigue test was performed for a standard specimen, and the bending fatigue life for the contact wire structure was then predicted using the maximum local stress occurring at the top of the contact wire. Lastly, the tested bending fatigue life of the structure was compared with the fatigue life predicted by the axial tension fatigue test for verification.

  18. Fatigue life prediction method for contact wire using maximum local stress

    International Nuclear Information System (INIS)

    Kim, Yong Seok; Haochuang, Li; Seok, Chang Sung; Koo, Jae Mean; Lee, Ki Won; Kwon, Sam Young; Cho, Yong Hyeon

    2015-01-01

    Railway contact wires supplying electricity to trains are exposed to repeated mechanical strain and stress caused by their own weight and discontinuous contact with a pantograph during train operation. Since the speed of railway transportation has increased continuously, railway industries have recently reported a number of contact wire failures caused by mechanical fatigue fractures instead of normal wear, which has been a more common failure mechanism. To secure the safety and durability of contact wires in environments with increased train speeds, a bending fatigue test on contact wire has been performed. The test equipment is too complicated to evaluate the fatigue characteristics of contact wire. Thus, the axial tension fatigue test was performed for a standard specimen, and the bending fatigue life for the contact wire structure was then predicted using the maximum local stress occurring at the top of the contact wire. Lastly, the tested bending fatigue life of the structure was compared with the fatigue life predicted by the axial tension fatigue test for verification.

  19. Effects of Consolidation Stress State on Normally Consolidated Clay

    DEFF Research Database (Denmark)

    Lade, Poul V.

    2000-01-01

    The effect of consolidation stress state on the stress-strain and strength characteristics has been studied from experiments on undisturbed block samples of a natural, normally consolidated clay known as San Francisco Bay Mud. The results of experiments on K0-consolidated, hollow cylinder specimens...... and on isotropically consolidated, cubical specimens, both tested in triaxial compression and extension, clearly showed the influence of the undisturbed fabric as well as the effect of the initial consolidation stress states. While the K0-consolidated specimens appeared to retain their original fabric and exhibit...

  20. Exertional headache and coronary ischemia despite normal electrocardiographic stress testing.

    Science.gov (United States)

    Cutrer, F Michael; Huerter, Karina

    2006-01-01

    Exertional headaches may under certain conditions reflect coronary ischemia. We report the case of a patient seen in a neurology referral practice whose exertional headaches, even in the face of two normal electrocardiographic stress tests and in the absence of underlying chest pain were the sole symptoms of coronary ischemia as detected by Tc-99m Sestamibi testing SPECT stress testing. Stent placement resulted in complete resolution of headaches. Exertional headache in the absence of chest pain may reflect underlying symptomatic coronary artery disease (CAD) even when conventional electrocardiographic stress testing does not indicate ischemia.

  1. The effects of shear and normal stress paths on rock friction

    International Nuclear Information System (INIS)

    Olsson, W.A.

    1990-01-01

    The effect of variable normal stress on the coefficient of friction of smooth artificial surfaces in welded tuff was studied. The shear stress response to changes in normal stress during constant-velocity sliding suggests that friction depends on the history of the normal stress; or, more generally, the path in shear/normal stress space. 6 refs., 5 figs

  2. NORMAL PRESSURE AND FRICTION STRESS MEASUREMENT IN ROLLING PROCESSES

    DEFF Research Database (Denmark)

    Henningsen, Poul; Arentoft, Mogens; Lagergren, Jonas

    2005-01-01

    the output from the transducer, the friction stress and normal pressure in the contact zone can be determined. The new concept differs from existing pin designs by a lower disturbance of lubricant film and material flow and limited penetration of material between transducer and roll. Aluminum, cupper...

  3. Combining ability studies on yield related traits in wheat under normal and water stress conditions

    International Nuclear Information System (INIS)

    Saeed, A.; Khan, A.S.; Khaliq, I.

    2010-01-01

    Six diverse wheat cultivars/lines viz; Baviacore, Nesser, 9247, 9252, 9258 and 9267 were crossed in a complete diallel fashion to develop 30 F1 crosses, which were tested along with their parents under normal and water stress conditions. Numerical analysis was made for spike density, number of grains per spike, 100-grain weight, biological yield, grain yield and harvest index. Significant differences among genotypic mean were observed in all of the traits under both conditions. GCA and SCA differences were significant for all the traits under study except spike density and 100-grain weight in both conditions. Wheat variety Nesser showed maximum general combining ability value for spike density under water stress conditions and maximum GCA value for biological yield and grain yield under irrigated condition. The variety Baviacore proved best general combiner for number of grains per spike and harvest index under both conditions while biological yield and grain yield under water stress condition. Variety 9252 found best general combiner for 100-grain weight under both condition. The cross 9252 x Nesser showed maximum specific combining ability value for spike density and biological yield under irrigated while for 100-grain weight under water stress condition. 9258 x 9252 exhibited maximum SCA for number of grains per spike under irrigated while 9258 x Nesser under water stress condition. 9267 x Nesser showed maximum SCA for 100-grain weight under irrigated condition while spike density under water stress condition. 9258 x 9247 was proved best combiner for grain yield and harvest index irrigated while 9267 x 9258 for biological yield, grain yield and harvest index under water stress condition. (author)

  4. In-shoe plantar tri-axial stress profiles during maximum-effort cutting maneuvers.

    Science.gov (United States)

    Cong, Yan; Lam, Wing Kai; Cheung, Jason Tak-Man; Zhang, Ming

    2014-12-18

    Soft tissue injuries, such as anterior cruciate ligament rupture, ankle sprain and foot skin problems, frequently occur during cutting maneuvers. These injuries are often regarded as associated with abnormal joint torque and interfacial friction caused by excessive external and in-shoe shear forces. This study simultaneously investigated the dynamic in-shoe localized plantar pressure and shear stress during lateral shuffling and 45° sidestep cutting maneuvers. Tri-axial force transducers were affixed at the first and second metatarsal heads, lateral forefoot, and heel regions in the midsole of a basketball shoe. Seventeen basketball players executed both cutting maneuvers with maximum efforts. Lateral shuffling cutting had a larger mediolateral braking force than 45° sidestep cutting. This large braking force was concentrated at the first metatarsal head, as indicated by its maximum medial shear stress (312.2 ± 157.0 kPa). During propulsion phase, peak shear stress occurred at the second metatarsal head (271.3 ± 124.3 kPa). Compared with lateral shuffling cutting, 45° sidestep cutting produced larger peak propulsion shear stress (463.0 ± 272.6 kPa) but smaller peak braking shear stress (184.8 ± 181.7 kPa), of which both were found at the first metatarsal head. During both cutting maneuvers, maximum medial and posterior shear stress occurred at the first metatarsal head, whereas maximum pressure occurred at the second metatarsal head. The first and second metatarsal heads sustained relatively high pressure and shear stress and were expected to be susceptible to plantar tissue discomfort or injury. Due to different stress distribution, distinct pressure and shear cushioning mechanisms in basketball footwear might be considered over different foot regions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. It is time to abandon "expected bladder capacity." Systematic review and new models for children's normal maximum voided volumes.

    Science.gov (United States)

    Martínez-García, Roberto; Ubeda-Sansano, Maria Isabel; Díez-Domingo, Javier; Pérez-Hoyos, Santiago; Gil-Salom, Manuel

    2014-09-01

    There is an agreement to use simple formulae (expected bladder capacity and other age based linear formulae) as bladder capacity benchmark. But real normal child's bladder capacity is unknown. To offer a systematic review of children's normal bladder capacity, to measure children's normal maximum voided volumes (MVVs), to construct models of MVVs and to compare them with the usual formulae. Computerized, manual and grey literature were reviewed until February 2013. Epidemiological, observational, transversal, multicenter study. A consecutive sample of healthy children aged 5-14 years, attending Primary Care centres with no urologic abnormality were selected. Participants filled-in a 3-day frequency-volume chart. Variables were MVVs: maximum of 24 hr, nocturnal, and daytime maximum voided volumes. diuresis and its daytime and nighttime fractions; body-measure data; and gender. The consecutive steps method was used in a multivariate regression model. Twelve articles accomplished systematic review's criteria. Five hundred and fourteen cases were analysed. Three models, one for each of the MVVs, were built. All of them were better adjusted to exponential equations. Diuresis (not age) was the most significant factor. There was poor agreement between MVVs and usual formulae. Nocturnal and daytime maximum voided volumes depend on several factors and are different. Nocturnal and daytime maximum voided volumes should be used with different meanings in clinical setting. Diuresis is the main factor for bladder capacity. This is the first model for benchmarking normal MVVs with diuresis as its main factor. Current formulae are not suitable for clinical use. © 2013 Wiley Periodicals, Inc.

  6. Microarray background correction: maximum likelihood estimation for the normal-exponential convolution

    DEFF Research Database (Denmark)

    Silver, Jeremy D; Ritchie, Matthew E; Smyth, Gordon K

    2009-01-01

    exponentially distributed, representing background noise and signal, respectively. Using a saddle-point approximation, Ritchie and others (2007) found normexp to be the best background correction method for 2-color microarray data. This article develops the normexp method further by improving the estimation...... is developed for exact maximum likelihood estimation (MLE) using high-quality optimization software and using the saddle-point estimates as starting values. "MLE" is shown to outperform heuristic estimators proposed by other authors, both in terms of estimation accuracy and in terms of performance on real data...

  7. Multivariate normal maximum likelihood with both ordinal and continuous variables, and data missing at random.

    Science.gov (United States)

    Pritikin, Joshua N; Brick, Timothy R; Neale, Michael C

    2018-04-01

    A novel method for the maximum likelihood estimation of structural equation models (SEM) with both ordinal and continuous indicators is introduced using a flexible multivariate probit model for the ordinal indicators. A full information approach ensures unbiased estimates for data missing at random. Exceeding the capability of prior methods, up to 13 ordinal variables can be included before integration time increases beyond 1 s per row. The method relies on the axiom of conditional probability to split apart the distribution of continuous and ordinal variables. Due to the symmetry of the axiom, two similar methods are available. A simulation study provides evidence that the two similar approaches offer equal accuracy. A further simulation is used to develop a heuristic to automatically select the most computationally efficient approach. Joint ordinal continuous SEM is implemented in OpenMx, free and open-source software.

  8. Pressurizer /Auxiliary Spray Piping Stress Analysis For Determination Of Lead Shielding Maximum Allow Able Load

    International Nuclear Information System (INIS)

    Setjo, Renaningsih

    2000-01-01

    Piping stress analysis for PZR/Auxiliary Spray Lines Nuclear Power Plant AV Unit I(PWR Type) has been carried out. The purpose of this analysis is to establish a maximum allowable load that is permitted at the time of need by placing lead shielding on the piping system on class 1 pipe, Pressurizer/Auxiliary Spray Lines (PZR/Aux.) Reactor Coolant Loop 1 and 4 for NPP AV Unit one in the mode 5 and 6 during outage. This analysis is intended to reduce the maximum amount of radiation dose for the operator during ISI ( In service Inspection) period.The result shown that the maximum allowable loads for 4 inches lines for PZR/Auxiliary Spray Lines is 123 lbs/feet

  9. Growth of contact area between rough surfaces under normal stress

    Science.gov (United States)

    Stesky, R. M.; Hannan, S. S.

    1987-05-01

    The contact area between deforming rough surfaces in marble, alabaster, and quartz was measured from thin sections of surfaces bonded under load with low viscosity resin epoxy. The marble and alabaster samples had contact areas that increased with stress at an accelerating rate. This result suggests that the strength of the asperity contacts decreased progressively during the deformation, following some form of strain weakening relationship. This conclusion is supported by petrographic observation of the thin sections that indicate that much of the deformation was cataclastic, with minor twinning of calcite and kinking of gypsum. In the case of the quartz, the observed contact area was small and increased approximately linearly with normal stress. Only the irreversible cataclastic deformation was observed; however strain-induced birefringence and cracking of the epoxy, not observed with the other rocks, suggests that significant elastic deformation occurred, but recovered during unloading.

  10. An iterative procedure for obtaining maximum-likelihood estimates of the parameters for a mixture of normal distributions, 2

    Science.gov (United States)

    Peters, B. C., Jr.; Walker, H. F.

    1976-01-01

    The problem of obtaining numerically maximum likelihood estimates of the parameters for a mixture of normal distributions is addressed. In recent literature, a certain successive approximations procedure, based on the likelihood equations, is shown empirically to be effective in numerically approximating such maximum-likelihood estimates; however, the reliability of this procedure was not established theoretically. Here, a general iterative procedure is introduced, of the generalized steepest-ascent (deflected-gradient) type, which is just the procedure known in the literature when the step-size is taken to be 1. With probability 1 as the sample size grows large, it is shown that this procedure converges locally to the strongly consistent maximum-likelihood estimate whenever the step-size lies between 0 and 2. The step-size which yields optimal local convergence rates for large samples is determined in a sense by the separation of the component normal densities and is bounded below by a number between 1 and 2.

  11. An iterative procedure for obtaining maximum-likelihood estimates of the parameters for a mixture of normal distributions

    Science.gov (United States)

    Peters, B. C., Jr.; Walker, H. F.

    1978-01-01

    This paper addresses the problem of obtaining numerically maximum-likelihood estimates of the parameters for a mixture of normal distributions. In recent literature, a certain successive-approximations procedure, based on the likelihood equations, was shown empirically to be effective in numerically approximating such maximum-likelihood estimates; however, the reliability of this procedure was not established theoretically. Here, we introduce a general iterative procedure, of the generalized steepest-ascent (deflected-gradient) type, which is just the procedure known in the literature when the step-size is taken to be 1. We show that, with probability 1 as the sample size grows large, this procedure converges locally to the strongly consistent maximum-likelihood estimate whenever the step-size lies between 0 and 2. We also show that the step-size which yields optimal local convergence rates for large samples is determined in a sense by the 'separation' of the component normal densities and is bounded below by a number between 1 and 2.

  12. Optimal design of the gerotor (2-ellipses) for reducing maximum contact stress

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Hyo Seo; Li, Sheng Huan [Dept. of Mechanical Convergence Technology, Pusan National University, Busan (Korea, Republic of); Kim, Chul [School of Mechanical Design and Manufacturing, Busan Institute of Science and Technology, Busan (Korea, Republic of)

    2016-12-15

    The oil pump, which is used as lubricator of engines and auto transmission, supplies working oil to the rotating elements to prevent wear. The gerotor pump is used widely in the automobile industry. When wear occurs due to contact between an inner rotor and an outer rotor, the efficiency of the gerotor pump decreases rapidly, and elastic deformation from the contacts also causes vibration and noise. This paper reports the optimal design of a gerotor with a 2-ellipses combined lobe shape that reduces the maximum contact stress. An automatic program was developed to calculate Hertzian contact stress of the gerotor using the Matlab and the effect of the design parameter on the maximum contact stress was analyzed. In addition, the method of theoretical analysis for obtaining the contact stress was verified by performing the fluid-structural coupled analysis using the commercial software, Ansys, considering both the driving force of the inner rotor and the fluid pressure, which is generated by working oil.

  13. Study on evaluation of normal range of maximum mouth opening among Indian adults using three finger index: A descriptive study

    Directory of Open Access Journals (Sweden)

    Ravleen Nagi

    2017-01-01

    Full Text Available Introduction: Early recognition of decreased or limited mouth opening in many pathological conditions is necessary for prompt diagnosis and to plan the treatment options judiciously. Therefore, it is essential to establish what constitutes normal opening for the population. Aim: This study was designed with an aim to consider the applicability of this method as an index to measure the maximum mouth opening (MMO among different age groups in an Indian population. Materials and Methods: Total 400 healthy participants were studied in the age range of 17 to 60 years and stratified into four groups according to their age ranges. The maximum interincisal distance and width of three fingers (index, middle, and ring fingers at the first distal interphalangeal folds of both right and left hand were measured using Vernier caliper. Statistical analysis was done using SPSS version 21 software package. Results: Results suggested that mean value and range of MMO for males was 51.00 mm (33.0–68.0 mm and for females it was 46.3 mm (39.0–58.0 mm. Mean values of MMO correlated significantly with the width of three fingers of left and right hand as shown by Pearson correlation test. Conclusion: The study suggested that three finger index is a convenient and reliable tool for assessing normal MMO and is a most appropriate method to normal from restricted mouth opening.

  14. Studying Maximum Plantar Stress per Insole Design Using Foot CT-Scan Images of Hyperelastic Soft Tissues

    Directory of Open Access Journals (Sweden)

    Ali Sarikhani

    2016-01-01

    Full Text Available The insole shape and the resulting plantar stress distribution have a pivotal impact on overall health. In this paper, by Finite Element Method, maximum stress value and stress distribution of plantar were studied for different insoles designs, which are the flat surface and the custom-molded (conformal surface. Moreover, insole thickness, heel’s height, and different materials were used to minimize the maximum stress and achieve the most uniform stress distribution. The foot shape and its details used in this paper were imported from online CT-Scan images. Results show that the custom-molded insole reduced maximum stress 40% more than the flat surface insole. Upon increase of thickness in both insole types, stress distribution becomes more uniform and maximum stress value decreases up to 10%; however, increase of thickness becomes ineffective above a threshold of 1 cm. By increasing heel height (degree of insole, maximum stress moves from heel to toes and becomes more uniform. Therefore, this scenario is very helpful for control of stress in 0.2° to 0.4° degrees for custom-molded insole and over 1° for flat insole. By changing the material of the insole, the value of maximum stress remains nearly constant. The custom-molded (conformal insole which has 0.5 to 1 cm thickness and 0.2° to 0.4° degrees is found to be the most compatible form for foot.

  15. Effects of adipose tissue distribution on maximum lipid oxidation rate during exercise in normal-weight women.

    Science.gov (United States)

    Isacco, L; Thivel, D; Duclos, M; Aucouturier, J; Boisseau, N

    2014-06-01

    Fat mass localization affects lipid metabolism differently at rest and during exercise in overweight and normal-weight subjects. The aim of this study was to investigate the impact of a low vs high ratio of abdominal to lower-body fat mass (index of adipose tissue distribution) on the exercise intensity (Lipox(max)) that elicits the maximum lipid oxidation rate in normal-weight women. Twenty-one normal-weight women (22.0 ± 0.6 years, 22.3 ± 0.1 kg.m(-2)) were separated into two groups of either a low or high abdominal to lower-body fat mass ratio [L-A/LB (n = 11) or H-A/LB (n = 10), respectively]. Lipox(max) and maximum lipid oxidation rate (MLOR) were determined during a submaximum incremental exercise test. Abdominal and lower-body fat mass were determined from DXA scans. The two groups did not differ in aerobic fitness, total fat mass, or total and localized fat-free mass. Lipox(max) and MLOR were significantly lower in H-A/LB vs L-A/LB women (43 ± 3% VO(2max) vs 54 ± 4% VO(2max), and 4.8 ± 0.6 mg min(-1)kg FFM(-1)vs 8.4 ± 0.9 mg min(-1)kg FFM(-1), respectively; P normal-weight women, a predominantly abdominal fat mass distribution compared with a predominantly peripheral fat mass distribution is associated with a lower capacity to maximize lipid oxidation during exercise, as evidenced by their lower Lipox(max) and MLOR. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  16. Shear Stress-Normal Stress (Pressure) Ratio Decides Forming Callus in Patients with Diabetic Neuropathy

    Science.gov (United States)

    Noguchi, Hiroshi; Takehara, Kimie; Ohashi, Yumiko; Suzuki, Ryo; Yamauchi, Toshimasa; Kadowaki, Takashi; Sanada, Hiromi

    2016-01-01

    Aim. Callus is a risk factor, leading to severe diabetic foot ulcer; thus, prevention of callus formation is important. However, normal stress (pressure) and shear stress associated with callus have not been clarified. Additionally, as new valuables, a shear stress-normal stress (pressure) ratio (SPR) was examined. The purpose was to clarify the external force associated with callus formation in patients with diabetic neuropathy. Methods. The external force of the 1st, 2nd, and 5th metatarsal head (MTH) as callus predilection regions was measured. The SPR was calculated by dividing shear stress by normal stress (pressure), concretely, peak values (SPR-p) and time integral values (SPR-i). The optimal cut-off point was determined. Results. Callus formation region of the 1st and 2nd MTH had high SPR-i rather than noncallus formation region. The cut-off value of the 1st MTH was 0.60 and the 2nd MTH was 0.50. For the 5th MTH, variables pertaining to the external forces could not be determined to be indicators of callus formation because of low accuracy. Conclusions. The callus formation cut-off values of the 1st and 2nd MTH were clarified. In the future, it will be necessary to confirm the effect of using appropriate footwear and gait training on lowering SPR-i. PMID:28050567

  17. Shear Stress-Normal Stress (Pressure Ratio Decides Forming Callus in Patients with Diabetic Neuropathy

    Directory of Open Access Journals (Sweden)

    Ayumi Amemiya

    2016-01-01

    Full Text Available Aim. Callus is a risk factor, leading to severe diabetic foot ulcer; thus, prevention of callus formation is important. However, normal stress (pressure and shear stress associated with callus have not been clarified. Additionally, as new valuables, a shear stress-normal stress (pressure ratio (SPR was examined. The purpose was to clarify the external force associated with callus formation in patients with diabetic neuropathy. Methods. The external force of the 1st, 2nd, and 5th metatarsal head (MTH as callus predilection regions was measured. The SPR was calculated by dividing shear stress by normal stress (pressure, concretely, peak values (SPR-p and time integral values (SPR-i. The optimal cut-off point was determined. Results. Callus formation region of the 1st and 2nd MTH had high SPR-i rather than noncallus formation region. The cut-off value of the 1st MTH was 0.60 and the 2nd MTH was 0.50. For the 5th MTH, variables pertaining to the external forces could not be determined to be indicators of callus formation because of low accuracy. Conclusions. The callus formation cut-off values of the 1st and 2nd MTH were clarified. In the future, it will be necessary to confirm the effect of using appropriate footwear and gait training on lowering SPR-i.

  18. Stress Softening Behavior in the Mucosa-Submucosa and Muscle Layers in Normal and Diabetic Rat Esophagus

    DEFF Research Database (Denmark)

    Jiang, Hongbo; Liao, Donghua; Zhao, Jingbo

    2015-01-01

    Background & aims: Stress softening is a feature of mechanical preconditioning in soft tissue. Previously, we demonstrated that esophageal stress softening is reversible by muscle activation with KCl. Since the esophagus consists of muscle and mucosa-submucosa layers, the aim was to study...... the stress softening behavior in these layers in normal and diabetic rat esophagus and how diabetes affect the reversibility of esophageal stress softening.Methods: Ten Wistar rats were injected with STZ and the average blood glucose level reached 25 mmol/L after 8 weeks. Ten rats were used as the normal......M KCl was added for maximum contraction for 3min. KCl was washed out to permit relaxation and contractions were eliminated by immersion into Ca2+-free solution. After 1h rest, the tubes were exposed to five repeated ramp distensions conformed to the aforesaid two series. Stress-strain curves were used...

  19. Polyphenols From Cutch Tree (Acacia catechu Willd.: Normalize In Vitro Oxidative Stress and Exerts Antiproliferative Activity

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar

    2017-10-01

    Full Text Available ABSTRACT Oxidative stress, being the main cause of most of the human diseases, has always been the highlight of research worldwide. This stress can be overcome by administration of natural polyphenols. The Acacia catechu Willd. has many refrences available in Ayurveda as important disease curative plant. Its leaves are investigated for ameliorating oxidative stress in present work. Leaves of A. catechu were extracted with 80% methanol to get methanol extract (AME. It was assessed for antioxidant activity using DPPH, ABTS, CUPRAC, ferric ion reducing, superoxide scavenging and peroxyl radical scavenging assays. DNA protective activity was also investigated using plasmid nicking assay. Further, antiproliferative activity was determined using MTT assay in various human cancer cell lines. The quantification of polyphenols was done by UHPLC analysis. Results confirmed that polyphenols of A. catechu were successful in normalizing oxidative stress. AME was found to be most effective in scavenging ABTS radicals while least effective in scavenging ferric ions. UHPLC analysis showed abundance of ellagic acid, rutin and quercetin in AME. Further, AME showed maximum antiproliferative activity against Hep G2 cancer cells. It is concluded that the polyphenols from A. catechu effectively remediates oxidative stress and hence can be used in curing numerous dreadful diseases.

  20. Frictional response of simulated faults to normal stresses perturbations probed with ultrasonic waves

    Science.gov (United States)

    Shreedharan, S.; Riviere, J.; Marone, C.

    2017-12-01

    We report on a suite of laboratory friction experiments conducted on saw-cut Westerly Granite surfaces to probe frictional response to step changes in normal stress and loading rate. The experiments are conducted to illuminate the fundamental processes that yield friction rate and state dependence. We quantify the microphysical frictional response of the simulated fault surfaces to normal stress steps, in the range of 1% - 600% step increases and decreases from a nominal baseline normal stress. We measure directly the fault slip rate and account for changes in slip rate with changes in normal stress and complement mechanical data acquisition by continuously probing the faults with ultrasonic pulses. We conduct the experiments at room temperature and humidity conditions in a servo controlled biaxial testing apparatus in the double direct shear configuration. The samples are sheared over a range of velocities, from 0.02 - 100 μm/s. We report observations of a transient shear stress and friction evolution with step increases and decreases in normal stress. Specifically, we show that, at low shear velocities and small increases in normal stress ( 5% increases), the shear stress evolves immediately with normal stress. We show that the excursions in slip rate resulting from the changes in normal stress must be accounted for in order to predict fault strength evolution. Ultrasonic wave amplitudes which first increase immediately in response to normal stress steps, then decrease approximately linearly to a new steady state value, in part due to changes in fault slip rate. Previous descriptions of frictional state evolution during normal stress perturbations have not adequately accounted for the effect of large slip velocity excursions. Here, we attempt to do so by using the measured ultrasonic amplitudes as a proxy for frictional state during transient shear stress evolution. Our work aims to improve understanding of induced and triggered seismicity with focus on

  1. Maximum stress estimation model for multi-span waler beams with deflections at the supports using average strains.

    Science.gov (United States)

    Park, Sung Woo; Oh, Byung Kwan; Park, Hyo Seon

    2015-03-30

    The safety of a multi-span waler beam subjected simultaneously to a distributed load and deflections at its supports can be secured by limiting the maximum stress of the beam to a specific value to prevent the beam from reaching a limit state for failure or collapse. Despite the fact that the vast majority of accidents on construction sites occur at waler beams in retaining wall systems, no safety monitoring model that can consider deflections at the supports of the beam is available. In this paper, a maximum stress estimation model for a waler beam based on average strains measured from vibrating wire strain gauges (VWSGs), the most frequently used sensors in construction field, is presented. The model is derived by defining the relationship between the maximum stress and the average strains measured from VWSGs. In addition to the maximum stress, support reactions, deflections at supports, and the magnitudes of distributed loads for the beam structure can be identified by the estimation model using the average strains. Using simulation tests on two multi-span beams, the performance of the model is evaluated by estimating maximum stress, deflections at supports, support reactions, and the magnitudes of distributed loads.

  2. Maximum Stress Estimation Model for Multi-Span Waler Beams with Deflections at the Supports Using Average Strains

    Directory of Open Access Journals (Sweden)

    Sung Woo Park

    2015-03-01

    Full Text Available The safety of a multi-span waler beam subjected simultaneously to a distributed load and deflections at its supports can be secured by limiting the maximum stress of the beam to a specific value to prevent the beam from reaching a limit state for failure or collapse. Despite the fact that the vast majority of accidents on construction sites occur at waler beams in retaining wall systems, no safety monitoring model that can consider deflections at the supports of the beam is available. In this paper, a maximum stress estimation model for a waler beam based on average strains measured from vibrating wire strain gauges (VWSGs, the most frequently used sensors in construction field, is presented. The model is derived by defining the relationship between the maximum stress and the average strains measured from VWSGs. In addition to the maximum stress, support reactions, deflections at supports, and the magnitudes of distributed loads for the beam structure can be identified by the estimation model using the average strains. Using simulation tests on two multi-span beams, the performance of the model is evaluated by estimating maximum stress, deflections at supports, support reactions, and the magnitudes of distributed loads.

  3. Use of Maximum Likelihood-Mixed Models to select stable reference genes: a case of heat stress response in sheep

    Directory of Open Access Journals (Sweden)

    Salces Judit

    2011-08-01

    Full Text Available Abstract Background Reference genes with stable expression are required to normalize expression differences of target genes in qPCR experiments. Several procedures and companion software have been proposed to find the most stable genes. Model based procedures are attractive because they provide a solid statistical framework. NormFinder, a widely used software, uses a model based method. The pairwise comparison procedure implemented in GeNorm is a simpler procedure but one of the most extensively used. In the present work a statistical approach based in Maximum Likelihood estimation under mixed models was tested and compared with NormFinder and geNorm softwares. Sixteen candidate genes were tested in whole blood samples from control and heat stressed sheep. Results A model including gene and treatment as fixed effects, sample (animal, gene by treatment, gene by sample and treatment by sample interactions as random effects with heteroskedastic residual variance in gene by treatment levels was selected using goodness of fit and predictive ability criteria among a variety of models. Mean Square Error obtained under the selected model was used as indicator of gene expression stability. Genes top and bottom ranked by the three approaches were similar; however, notable differences for the best pair of genes selected for each method and the remaining genes of the rankings were shown. Differences among the expression values of normalized targets for each statistical approach were also found. Conclusions Optimal statistical properties of Maximum Likelihood estimation joined to mixed model flexibility allow for more accurate estimation of expression stability of genes under many different situations. Accurate selection of reference genes has a direct impact over the normalized expression values of a given target gene. This may be critical when the aim of the study is to compare expression rate differences among samples under different environmental

  4. Designing experiments for maximum information from cyclic oxidation tests and their statistical analysis using half Normal plots

    International Nuclear Information System (INIS)

    Coleman, S.Y.; Nicholls, J.R.

    2006-01-01

    Cyclic oxidation testing at elevated temperatures requires careful experimental design and the adoption of standard procedures to ensure reliable data. This is a major aim of the 'COTEST' research programme. Further, as such tests are both time consuming and costly, in terms of human effort, to take measurements over a large number of cycles, it is important to gain maximum information from a minimum number of tests (trials). This search for standardisation of cyclic oxidation conditions leads to a series of tests to determine the relative effects of cyclic parameters on the oxidation process. Following a review of the available literature, databases and the experience of partners to the COTEST project, the most influential parameters, upper dwell temperature (oxidation temperature) and time (hot time), lower dwell time (cold time) and environment, were investigated in partners' laboratories. It was decided to test upper dwell temperature at 3 levels, at and equidistant from a reference temperature; to test upper dwell time at a reference, a higher and a lower time; to test lower dwell time at a reference and a higher time and wet and dry environments. Thus an experiment, consisting of nine trials, was designed according to statistical criteria. The results of the trial were analysed statistically, to test the main linear and quadratic effects of upper dwell temperature and hot time and the main effects of lower dwell time (cold time) and environment. The nine trials are a quarter fraction of the 36 possible combinations of parameter levels that could have been studied. The results have been analysed by half Normal plots as there are only 2 degrees of freedom for the experimental error variance, which is rather low for a standard analysis of variance. Half Normal plots give a visual indication of which factors are statistically significant. In this experiment each trial has 3 replications, and the data are analysed in terms of mean mass change, oxidation kinetics

  5. Normal stress databases in myocardial perfusion scintigraphy – how many subjects do you need?

    DEFF Research Database (Denmark)

    Trägårdh, Elin; Sjöstrand, Karl; Edenbrandt, Lars

    2012-01-01

    ) for male, NC for female, attenuation‐corrected images (AC) for male and AC for female subjects. 126 male and 205 female subjects were included. The normal database was created by alternatingly computing the mean of all normal subjects and normalizing the subjects with respect to this mean, until...... convergence. Coefficients of variation (CV) were created for increasing number of included patients in the four different normal stress databases. Normal stress databases with ...Commercial normal stress databases in myocardial perfusion scintigraphy (MPS) commonly consist of 30–40 individuals. The aim of the study was to determine how many subjects are needed. Four normal stress databases were developed using patients who underwent 99mTc MPS: non‐corrected images (NC...

  6. Intranasal Oxytocin Normalizes Amygdala Functional Connectivity in Posttraumatic Stress Disorder

    NARCIS (Netherlands)

    Koch, Saskia B. J.; van Zuiden, Mirjam; Nawijn, Laura; Frijling, Jessie L.; Veltman, Dick J.; Olff, Miranda

    2016-01-01

    The neuropeptide oxytocin (OT) has been suggested as a promising pharmacological agent for medication-enhanced psychotherapy in posttraumatic stress disorder (PTSD) because of its anxiolytic and prosocial properties. We therefore investigated the behavioral and neurobiological effects of a single

  7. Forecasting Portfolio Risk in Normal and Stressed Markets

    OpenAIRE

    Bhansali, Vineer; Wise, Mark B.

    2001-01-01

    The instability of historical risk factor correlations renders their use in estimating portfolio risk extremely questionable. In periods of market stress correlations of risk factors have a tendency to quickly go well beyond estimated values. For instance, in times of severe market stress, one would expect with certainty to see the correlation of yield levels and credit spreads go to -1, even though historical estimates will miss this region of correlation. This event might lead to realized p...

  8. Blood lactate kinetics in normal and stress-susceptible pigs

    International Nuclear Information System (INIS)

    Darrah, P.S.; Beitz, D.C.; Topel, D.G.; Christian, L.L.

    1981-01-01

    In vitro rates of lactate metabolism were determined in stress-susceptible (SS) and stress-resistant (SR) pigs. Three SR and three SS pigs were given 20 muCi of [U-/sup 14/C] L-lactate by a single injection method and resting blood lactate kinetics were measured. Seventeen blood samples were taken during the 60 min after injection. Lactate was separated from the deproteinized plasma by silicic acid column chromatography, and specific radioactivity was determined. Kinetic characteristics were calculated from plots of specific activity versus time. Pigs met steady-state requirements during the sampling period. There were no differences in kinetic characteristics of resting SS and SR pigs. Later, a second isotope injection was given after 5 min of electrical stress. Lactate pool sizes increased similarly in both types of pigs after stress; however, SS pigs had greater plasma lactate concentrations after stress. It is concluded that SS and SR pigs respond differently to stress but have similar capacities to metabolize lactate while resting

  9. COMPARISON OF NORMALIZED MAXIMUM AEROBIC CAPACITY AND BODY COMPOSITION OF SUMO WRESTLERS TO ATHLETES IN COMBAT AND OTHER SPORTS

    Directory of Open Access Journals (Sweden)

    Matthew D. Beekley

    2006-07-01

    Full Text Available Sumo wrestling is unique in combat sport, and in all of sport. We examined the maximum aerobic capacity and body composition of sumo wrestlers and compared them to untrained controls. We also compared "aerobic muscle quality", meaning VO2max normalized to predicted skeletal muscle mass (SMM (VO2max /SMM, between sumo wrestlers and controls and among previously published data for male athletes from combat, aerobic, and power sports. Sumo wrestlers, compared to untrained controls, had greater (p < 0.05 body mass (mean ± SD; 117.0 ± 4.9 vs. 56.1 ± 9.8 kg, percent fat (24.0 ± 1.4 vs. 13.3 ± 4.5, fat-free mass (88.9 ± 4.2 vs. 48.4 �� 6.8 kg, predicted SMM (48.2 ± 2.9 vs. 20.6 ± 4.7 kg and absolute VO2max (3.6 ± 1.3 vs. 2.5 ± 0.7 L·min-1. Mean VO2max /SMM (ml·kg SMM-1·min-1 was significantly different (p < 0.05 among aerobic athletes (164.8 ± 18.3, combat athletes (which was not different from untrained controls; 131.4 ± 9.3 and 128.6 ± 13.6, respectively, power athletes (96.5 ± 5.3, and sumo wrestlers (71.4 ± 5.3. There was a strong negative correlation (r = - 0.75 between percent body fat and VO2max /SMM (p < 0.05. We conclude that sumo wrestlers have some of the largest percent body fat and fat-free mass and the lowest "aerobic muscle quality" (VO2max /SMM, both in combat sport and compared to aerobic and power sport athletes. Additionally, it appears from analysis of the relationship between SMM and absolute VO2max for all sports that there is a "ceiling" at which increases in SMM do not result in additional increases in absolute VO2max

  10. Growth Normal Faulting at the Western Edge of the Metropolitan Taipei Basin since the Last Glacial Maximum, Northern Taiwan

    Directory of Open Access Journals (Sweden)

    Chih-Tung Chen

    2010-01-01

    Full Text Available Growth strata analysis is an useful tool in understanding kinematics and the evolution of active faults as well as the close relationship between sedimentation and tectonics. Here we present the Shanchiao Fault as a case study which is an active normal fault responsible for the formation of the 700-m-thick late Quaternary deposits in Taipei Basin at the northern tip of the Taiwan mountain belt. We compiled a sedimentary record, particularly the depositional facies and their dated ages, at three boreholes (SCF-1, SCF-2 and WK-1, from west to east along the Wuku Profile that traverses the Shanchiao Fault at its central segment. By incorporating the global sea level change curve, we find that thickness changes of sediments and changes of depositional environments in the Wuku area are in a good agreement with a rapid sea level rise since the Last Glacial Maximum (LGM of about 23 ka. Combining depositional facies changes and their ages with their thickness, we are able to introduce a simple back-stripping method to reconstruct the evolution of growing strata across the Shanchiao Fault since the LGM. We then estimate the vertical tectonic slip rate since 23 ka, which exhibits 2.2 mm yr-1 between SCF-2 and WK-1 and 1.1 mm yr-1 between SCF-1 and SCF-2. We also obtain the Holocene tectonic subsidence rate of 2.3 mm yr-1 at WK-1 and 0.9 mm yr-1 at SCF-2 since 8.4 ka. We thus conclude that the fault zone consists of a high-angle main fault to the east between SCF-2 and WK-1 and a western lower-angle branch fault between SCF-1 and SCF-2, resembling a tulip structure developed under sinistral transtensional tectonism. We find that a short period of 600-yr time span in 9 - 8.4 ka shows important tectonic subsidence of 7.4 and 3.3 m for the main and branch fault, respectively, consistent with possible earthquake events proposed by previous studies during that time. A correlation between geomorphology and subsurface geology in the Shanchiao Fault zone shows

  11. The Influence of Pressure Distribution on the Maximum Values of Stress in FEM Analysis of Plain Bearings

    Directory of Open Access Journals (Sweden)

    Vasile Cojocaru

    2016-12-01

    Full Text Available Several methods can be used in the FEM studies to apply the loads on a plain bearing. The paper presents a comparative analysis of maximum stress obtained for three loading scenarios: resultant force applied on the shaft – bearing assembly, variable pressure with sinusoidal distribution applied on the bearing surface, variable pressure with parabolic distribution applied on the bearing surface.

  12. Palladium induced oxidative stress and cell death in normal ...

    African Journals Online (AJOL)

    Our findings clearly indicate that Pd induces reactive oxygen species (ROS) formation and oxidative stress, mitochondrial and lysosomal injury and finally cell death. These effects are reversed by antioxidants and ROS scavengers, mitochondrial permeability transmission [1] pore sealing agent, ATP progenitor, and ...

  13. Oxidative stress in normal hematopoietic stem cells and leukemia.

    Science.gov (United States)

    Samimi, Azin; Kalantari, Heybatullah; Lorestani, Marzieh Zeinvand; Shirzad, Reza; Saki, Najmaldin

    2018-04-01

    Leukemia is developed following the abnormal proliferation of immature hematopoietic cells in the blood when hematopoietic stem cells lose the ability to turn into mature cells at different stages of maturation and differentiation. Leukemia initiating cells are specifically dependent upon the suppression of oxidative stress in the hypoglycemic bone marrow (BM) environment to be able to start their activities. Relevant literature was identified by a PubMed search (2000-2017) of English-language literature using the terms 'oxidative stress,' 'reactive oxygen species,' 'hematopoietic stem cell,' and 'leukemia.' The generation and degradation of free radicals is a main component of the metabolism in aerobic organisms. A certain level of ROS is required for proper cellular function, but values outside this range will result in oxidative stress (OS). Long-term overactivity of reactive oxygen species (ROS) has harmful effects on the function of cells and their vital macromolecules, including the transformation of proteins into autoantigens and increased degradation of protein/DNA, which eventually leads to the change in pathways involved in the development of cancer and several other disorders. According to the metabolic disorders of cancer, the relationship between OS changes, the viability of cancer cells, and their response to chemotherapeutic agents affecting this pathway are undeniable. Recently, studies have been conducted to determine the effect of herbal agents and cancer chemotherapy drugs on oxidative stress pathways. By emphasizing the role of oxidative stress on stem cells in the incidence of leukemia, this paper attempts to state and summarize this subject. © 2018 APMIS. Published by John Wiley & Sons Ltd.

  14. Development of in-situ rock shear test under low compressive to tensile normal stress

    International Nuclear Information System (INIS)

    Nozaki, Takashi; Shin, Koichi

    2003-01-01

    The purpose of this study is to develop an in-situ rock shear testing method to evaluate the shear strength under low normal stress condition including tensile stress, which is usually ignored in the assessment of safety factor of the foundations for nuclear power plants against sliding. The results are as follows. (1) A new in-situ rock shear testing method is devised, in which tensile normal stress can be applied on the shear plane of a specimen by directly pulling up a steel box bonded to the specimen. By applying the counter shear load to cancel the moment induced by the main shear load, it can obtain shear strength under low normal stress. (2) Some model tests on Oya tuff and diatomaceous mudstone have been performed using the developed test method. The shear strength changed smoothly from low values at tensile normal stresses to higher values at compressive normal stresses. The failure criterion has been found to be bi-linear on the shear stress vs normal stress plane. (author)

  15. Fracture permeability under effect of normal and shear stress: A preliminary experimental investigation

    International Nuclear Information System (INIS)

    Mohanty, S.; Manteufel, R.D.; Chowdhury, A.H.

    1995-01-01

    The change in fracture permeability under mechanical loads have been investigated. An apparatus has been developed to measure change in fracture permeability, when a single fracture is subjected to normal and shear stress. Both radial and linear flow experiments have been conducted by modifying a direct shear test apparatus. Preliminary results suggest a 35-percent change in fracture permeability under normal stress to 8 MPa and nearly 350 percent under shear displacement of 9.9254 m (1 in.) at 5 MPa normal stress. Effort is underway to separate the permeability change due to gouge material production from that of due to dilation

  16. Quantification of the right ventricular wall using stress myocardial emission computed tomography with thallium-201 in normal subjects

    International Nuclear Information System (INIS)

    Akanabe, Hiroshi; Oshima, Motoo; Sakuma, Sadayuki; Yamamoto, Shuhei; Kawai, Naoki; Sotobata, Iwao

    1985-01-01

    Although many studies of quantitative analysis of left ventricular myocardial wall (LVMW) have been reported using stress thallium-201 (Tl-201), few reports of right ventricular myocardial wall (RVMW) have been estimated. In this study we determined whether single photon emission computed tomography (SPECT) with Tl-201 could accurately define normal range of RVMW in normal subjects. Twelve persons who have no valvular disease, nor coronary artery disease were included in this study. Stress SPECT study was reconstructed to make a short axial images of ventricles. RVMW and LVMW were flagged by mamual. Each ventricle was divided into 36 parts at every 10 degree. Relative activity counts in each ventricle were calculated as a percent counts of maximum counts in left ventricle. The normal range of RVMW with stress SPECT was as follows: anterior wall (33.2 +- 11.4 %, mean +- 2 standard deviation, -62.7 +- 18.4 %), free wall (30.1 +- 12.4 % - 38.5 +- 8.8 %), inferior wall (40.4 +- 7.8 % - 60.0 +- 21.4 %), septal wall (65.2 +- 17.2 % - 71.1 +- 14.2 %). Above the results, SPECT with Tl-201 can accurately define the normal range of RVMW, and this method is usefull to quantify the degree of ischemia and hypertrophy in RVMW. (author)

  17. Towards the prediction of pre-mining stresses in the European continent. [Estimates of vertical and probable maximum lateral stress in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Blackwood, R. L.

    1980-05-15

    There are now available sufficient data from in-situ, pre-mining stress measurements to allow a first attempt at predicting the maximum stress magnitudes likely to occur in a given mining context. The sub-horizontal (lateral) stress generally dominates the stress field, becoming critical to stope stability in many cases. For cut-and-fill mining in particular, where developed fill pressures are influenced by lateral displacement of pillars or stope backs, extraction maximization planning by mathematical modelling techniques demands the best available estimate of pre-mining stresses. While field measurements are still essential for this purpose, in the present paper it is suggested that the worst stress case can be predicted for preliminary design or feasibility study purposes. In the Eurpoean continent the vertical component of pre-mining stress may be estimated by adding 2 MPa to the pressure due to overburden weight. The maximum lateral stress likely to be encountered is about 57 MPa at depths of some 800m to 1000m below the surface.

  18. Stress in Mothers of Hearing Impaired Children Compared to Mothers of Normal and Other Disabled Children

    Directory of Open Access Journals (Sweden)

    Mahnaz Aliakbari Dehkordi

    2011-06-01

    Full Text Available Background and Aim: Stress is associated with life satisfaction and also development of some physical diseases. Birth of a disabled child with mental or physical disability (especially deaf or blind children, impose an enormous load of stress on their parents especially the mothers. This study compared stress levels of mothers with hearing impaired children and mothers of normal children or with other disabilities.Methods: In this study, cluster random sampling was performed in Karaj city. 120 mothers in four groups of having a child with mental retardation, low vision, hearing impairment and with normal children were included. Family inventory of life events (FILE of Mc Cubbin et al. was used to determine stress level in four groups of mothers.Results: The results of this research indicated a significant difference (p<0.05 between stress levels of mothers with hearing impaired children and mothers of other disabled and normal children in subscales of intra-family stress, finance and business strains, stress of job transitions, stress of illness and family care and family members "in and out''. There was no difference between compared groups in other subscales.Conclusion: Since deafness is a hidden inability, the child with hearing impairment has a set of social and educational problems causing great stress for parents, especially to mother. In order to decrease mother’s stress, it is suggested to provide more family consultation, adequate social support and to run educational classes for parents to practice stress coping strategies.

  19. Perineal Ultrasound Findings of Stress Urinary Incontinence : Differentiation from Normal Findings

    International Nuclear Information System (INIS)

    Baek, Seung Yon; Chung, Eun Chul; Rhee, Chung Sik; Suh, Jeong Soo

    1995-01-01

    Perineal ultrasonography is a noninvasive method that is easier than chain cystoure-thrography in the diagnosis of stress urinary incontinence(SUI). We report the findings of stress urinary incontinence at peritoneal ultrasound and its differential points form normal control. Twenty-two patients with SUI and l6 normal controls were included in our study. Aloka SSD 650 with 3.5MHz convex transducer was used, and sagittal image through the bladder, bladder base, urethrovesical junction and pubis was obtained from the vulva area, We measured thepdsterior urethrovesical angle(PUVA) at rest and stress, and calculated the difference between the two angles. We also measured the distance of bladder neck descent during stress and the diameter of proximal urethra at rest. The data were analyzed with student t-test. At rest, PUVA was 135.3 .deg. in patients with SUI group and 134.5 .deg. in normal control group(P=0.8376). During streets, PUVA was 149.5 .deg. in SUI group and 142.1 .deg. in normal group(P=0.0135). The difference PUVAs at rest and during stress was 14.2 .deg. in SUI group and 7.6 .deg. in normal group(P=0.0173). The distance of bladder neck descent during stress was 14.5mm in SUI group and 9.8mm in normal group(P=0.0029). The diameter of proxiaml urethra at rest was 4.4mm in SUI group and 3.6mm in normal group(P=0.0385). In conclusion, ultrasound parameters that include the PUVA during stress, the difference between PUVAs at rest and during stress, the distance of bladder neck descent during stress and the diameter of proximal ureyhra at rest are useful in diagnosis of the stress urinary incontinence

  20. Perineal Ultrasound Findings of Stress Urinary Incontinence : Differentiation from Normal Findings

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Seung Yon; Chung, Eun Chul; Rhee, Chung Sik; Suh, Jeong Soo [Ewha Womans University Hospital, Seoul (Korea, Republic of)

    1995-06-15

    Perineal ultrasonography is a noninvasive method that is easier than chain cystoure-thrography in the diagnosis of stress urinary incontinence(SUI). We report the findings of stress urinary incontinence at peritoneal ultrasound and its differential points form normal control. Twenty-two patients with SUI and l6 normal controls were included in our study. Aloka SSD 650 with 3.5MHz convex transducer was used, and sagittal image through the bladder, bladder base, urethrovesical junction and pubis was obtained from the vulva area, We measured thepdsterior urethrovesical angle(PUVA) at rest and stress, and calculated the difference between the two angles. We also measured the distance of bladder neck descent during stress and the diameter of proximal urethra at rest. The data were analyzed with student t-test. At rest, PUVA was 135.3 .deg. in patients with SUI group and 134.5 .deg. in normal control group(P=0.8376). During streets, PUVA was 149.5 .deg. in SUI group and 142.1 .deg. in normal group(P=0.0135). The difference PUVAs at rest and during stress was 14.2 .deg. in SUI group and 7.6 .deg. in normal group(P=0.0173). The distance of bladder neck descent during stress was 14.5mm in SUI group and 9.8mm in normal group(P=0.0029). The diameter of proxiaml urethra at rest was 4.4mm in SUI group and 3.6mm in normal group(P=0.0385). In conclusion, ultrasound parameters that include the PUVA during stress, the difference between PUVAs at rest and during stress, the distance of bladder neck descent during stress and the diameter of proximal ureyhra at rest are useful in diagnosis of the stress urinary incontinence

  1. The Application of Normal Stress Reduction Function in Tilt Tests for Different Block Shapes

    Science.gov (United States)

    Kim, Dong Hyun; Gratchev, Ivan; Hein, Maw; Balasubramaniam, Arumugam

    2016-08-01

    This paper focuses on the influence of the shapes of rock cores, which control the sliding or toppling behaviours in tilt tests for the estimation of rock joint roughness coefficients (JRC). When the JRC values are estimated by performing tilt tests, the values are directly proportional to the basic friction of the rock material and the applied normal stress on the sliding planes. Normal stress obviously varies with the shape of the sliding block, and the basic friction angle is also affected by the sample shapes in tilt tests. In this study, the shapes of core blocks are classified into three representative shapes and those are created using plaster. Using the various shaped artificial cores, a set of tilt tests is carried out to identify the shape influences on the normal stress and the basic friction angle in tilt tests. The test results propose a normal stress reduction function to estimate the normal stress for tilt tests according to the sample shapes based on Barton's empirical equation. The proposed normal stress reduction functions are verified by tilt tests using artificial plaster joints and real rock joint sets. The plaster joint sets are well matched and cast in detailed printed moulds using a 3D printing technique. With the application of the functions, the obtained JRC values from the tilt tests using the plaster samples and the natural rock samples are distributed within a reasonable JRC range when compared with the measured values.

  2. Shear-coupled grain-boundary migration dependence on normal strain/stress

    Science.gov (United States)

    Combe, N.; Mompiou, F.; Legros, M.

    2017-08-01

    In specific conditions, grain-boundary (GB) migration occurs in polycrystalline materials as an alternative vector of plasticity compared to the usual dislocation activity. The shear-coupled GB migration, the expected most efficient GB based mechanism, couples the GB motion to an applied shear stress. Stresses on GB in polycrystalline materials seldom have, however, a unique pure shear component. This work investigates the influence of a normal strain on the shear coupled migration of a Σ 13 (320 )[001 ] GB in a copper bicrystal using atomistic simulations. We show that the yield shear stress inducing the GB migration strongly depends on the applied normal stress. Beyond, the application of a normal stress on this GB qualitatively modifies the GB migration: while the Σ 13 (320 )[001 ] GB shear couples following the 〈110 〉 migration mode without normal stress, we report the observation of the 〈010 〉 mode under a sufficiently high tensile normal stress. Using the nudge elastic band method, we uncover the atomistic mechanism of this 〈010 〉 migration mode and energetically characterize it.

  3. Intranasal Oxytocin Normalizes Amygdala Functional Connectivity in Posttraumatic Stress Disorder.

    Science.gov (United States)

    Koch, Saskia B J; van Zuiden, Mirjam; Nawijn, Laura; Frijling, Jessie L; Veltman, Dick J; Olff, Miranda

    2016-07-01

    The neuropeptide oxytocin (OT) has been suggested as a promising pharmacological agent for medication-enhanced psychotherapy in posttraumatic stress disorder (PTSD) because of its anxiolytic and prosocial properties. We therefore investigated the behavioral and neurobiological effects of a single intranasal OT administration (40 IU) in PTSD patients. We conducted a randomized, placebo-controlled, cross-over resting-state fMRI study in male and female police officers with (n=37, 21 males) and without PTSD (n=40, 20 males). We investigated OT administration effects on subjective anxiety and functional connectivity of basolateral (BLA) and centromedial (CeM) amygdala subregions with prefrontal and salience processing areas. In PTSD patients, OT administration resulted in decreased subjective anxiety and nervousness. Under placebo, male PTSD patients showed diminished right CeM to left ventromedial prefrontal cortex (vmPFC) connectivity compared with male trauma-exposed controls, which was reinstated after OT administration. Additionally, female PTSD patients showed enhanced right BLA to bilateral dorsal anterior cingulate cortex (dACC) connectivity compared with female trauma-exposed controls, which was dampened after OT administration. Although caution is warranted, our findings tentatively suggest that OT has the potential to diminish anxiety and fear expression of the amygdala in PTSD, either via increased control of the vmPFC over the CeM (males) or via decreased salience processing of the dACC and BLA (females). Our findings add to accumulating evidence that OT administration could potentially enhance treatment response in PTSD.

  4. Normal Stresses in a Granular Material Under Falling Weight Deflectometer loading

    DEFF Research Database (Denmark)

    Ullidtz, Per; Askegaar, Vagn; Sjølin, Finn Ole

    1996-01-01

    The vertical normal stress under a falling weight deflectometer (FWD) was measured in a sand. The material had more than 90 percent falling within the sand fraction from 60 micrometer to 2 mm. The stress was measured with three different transducers. All transducers were installed at a depth of 2...

  5. Effect of normal stress under an excitation in poroelastic flat slabs

    African Journals Online (AJOL)

    user

    Biot's poroelastic theory is employed to investigate stresses under an ... Keywords: Flat slab, radial normal stress, pervious surface, impervious ... warranted, because of above mentioned applications. ...... M.Tajuddin, and G. Narayan Reddy, Effect of boundaries on the dynamic interaction of a liquid filled porous layer and a.

  6. Stress does not affect ghrelin secretion in obese and normal weight women.

    Science.gov (United States)

    Kiessl, Gundula R R; Laessle, Reinhold G

    2017-03-01

    Stress has been supposed to increase appetite. The biological basis of this phenomenon may be a stress-induced alteration of the secretion of GUT peptides such as ghrelin. Stress-induced changes in ghrelin secretion could be a biological basis of overeating and a factor contributing to the development of obesity. Aim of the study was to analyze the effect of acute psychosocial stress on ghrelin secretion in obese and normal weight women. We compared pre- and postprandial plasma ghrelin secretion of 42 obese and 43 normal weight women in a randomized crossover design. Ghrelin and cortisol concentrations were measured and ratings of stress were also recorded in response to a psychological stressor (Trier Social Stress Test, TSST). Ghrelin samples were collected in the fasting state one time before participating in the TSST and one time before a control session. After the TSST, respectively, control session participants had a standardized ad libitum meal. 30 and 60 min after the TSST, respectively, control session preprandial ghrelin was measured again. Obese women showed lower pre- and postprandial release of ghrelin than normal weight controls. Moreover, obese women showed inhibited postprandial decrease of ghrelin secretion. Stress did not affect postprandial ghrelin secretion, but inhibited food intake in all subjects. The present data provide further evidence of altered ghrelin release in obesity. Acute stress did not affect postprandial ghrelin secretion, but inhibited food intake in all subjects. Results are discussed with regard to biological and psychological regulation of hunger and satiety in obesity.

  7. Optimization of hip joint replacement location to decrease maximum von Mi ses Stress

    International Nuclear Information System (INIS)

    Pourjamali, H.; Najarian, S.; Katoozian, H. R.

    2001-01-01

    Hip replacement is used for inoperable femur head injuries and femur fractures where internal fixation can not be used. This operation is one of the most common orthopedic operations that many research have been done about it. Among these we can mention implant and cement materials and composites optimization and also implant shape optimization. This study was designed to optimize artificial hip joint position (placement) to decrease maximal von mi sees stress. First, a model of femur and implant were made and then a computer program was written with the ability to change the position of implant through an acceptable range in the femur. In each of these positions, the program simulated femur and implant according to finite element method and made, applied forces were weight and muscle traction. Our findings show that a small deviation of the implant from femur bone center causes a considerable decrease in von mi sees stress that consequently results in longer maintenance of the implant

  8. The antidepressant fluoxetine normalizes the nuclear glucocorticoid receptor evoked by psychosocial stress

    Science.gov (United States)

    Mitić, M.; Simić, I.; Djordjević, J.; Radojčić, M. B.; Adžić, M.

    2011-12-01

    Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the pathophysiology of depression and stress disorders. Glucocorticoids, key regulators of the stress response, exert diverse effects on cellular processes in the hippocampus. Beside non-genomic pathways, glucocorticoid effects are mediated through activation of the glucocorticoid receptor (GR), a ligand activated transcriptional factor that belongs to the nuclear hormone receptor superfamily. We analysed the GR protein levels both in the cytoplasmic and nuclear compartments of the hippocampus of Wistar rats exposed to chronic psychosocial isolation stress upon chronic fluoxetine (FLU) treatment. Under chronic stress, corticosterone levels (CORT) were decreased compared to the control, and treatment with FLU did not change its level in the stressed rats. At the molecular level, FLU normalized the level of nuclear GR protein in the hippocampus of the stressed rats. Discrepancy between normalization of nuclear GR in the hippocampus and lack of normalization of HPA axis activity judged by CORT, suggests that other brain structures such as the amygdale and prefrontal cortex that also regulate HPA axis activity, seem not to be normalized by the FLU treatment used in our study.

  9. Static stress changes associated with normal faulting earthquakes in South Balkan area

    Science.gov (United States)

    Papadimitriou, E.; Karakostas, V.; Tranos, M.; Ranguelov, B.; Gospodinov, D.

    2007-10-01

    Activation of major faults in Bulgaria and northern Greece presents significant seismic hazard because of their proximity to populated centers. The long recurrence intervals, of the order of several hundred years as suggested by previous investigations, imply that the twentieth century activation along the southern boundary of the sub-Balkan graben system, is probably associated with stress transfer among neighbouring faults or fault segments. Fault interaction is investigated through elastic stress transfer among strong main shocks ( M ≥ 6.0), and in three cases their foreshocks, which ruptured distinct or adjacent normal fault segments. We compute stress perturbations caused by earthquake dislocations in a homogeneous half-space. The stress change calculations were performed for faults of strike, dip, and rake appropriate to the strong events. We explore the interaction between normal faults in the study area by resolving changes of Coulomb failure function ( ΔCFF) since 1904 and hence the evolution of the stress field in the area during the last 100 years. Coulomb stress changes were calculated assuming that earthquakes can be modeled as static dislocations in an elastic half-space, and taking into account both the coseismic slip in strong earthquakes and the slow tectonic stress buildup associated with major fault segments. We evaluate if these stress changes brought a given strong earthquake closer to, or sent it farther from, failure. Our modeling results show that the generation of each strong event enhanced the Coulomb stress on along-strike neighbors and reduced the stress on parallel normal faults. We extend the stress calculations up to present and provide an assessment for future seismic hazard by identifying possible sites of impending strong earthquakes.

  10. Comparing of Normal Stress Distribution in Static and Dynamic Soil-Structure Interaction Analyses

    International Nuclear Information System (INIS)

    Kholdebarin, Alireza; Massumi, Ali; Davoodi, Mohammad; Tabatabaiefar, Hamid Reza

    2008-01-01

    It is important to consider the vertical component of earthquake loading and inertia force in soil-structure interaction analyses. In most circumstances, design engineers are primarily concerned about the analysis of behavior of foundations subjected to earthquake-induced forces transmitted from the bedrock. In this research, a single rigid foundation with designated geometrical parameters located on sandy-clay soil has been modeled in FLAC software with Finite Different Method and subjected to three different vertical components of earthquake records. In these cases, it is important to evaluate effect of footing on underlying soil and to consider normal stress in soil with and without footing. The distribution of normal stress under the footing in static and dynamic states has been studied and compared. This Comparison indicated that, increasing in normal stress under the footing caused by vertical component of ground excitations, has decreased dynamic vertical settlement in comparison with static state

  11. Estimation of fracture conditions of ceramics by thermal shock with laser beams based on the maximum compressive stress criterion

    International Nuclear Information System (INIS)

    Akiyama, Shigeru; Amada, Shigeyasu.

    1992-01-01

    Structural ceramics are attracting attention in the development of space planes, aircraft and nuclear fusion reactors because they have excellent wear-resistant and heat-resistant characteristics. However, in some applications it is anticipated that they will be exposed to very-high-temperature environments of the order of thousands of degrees. Therefore, it is very important to investigate their thermal shock characteristics. In this report, the distributions of temperatures and thermal stresses of cylindrically shaped ceramics under irradiation by laser beams are discussed using the finite-element computer code (MARC) with arbitrary quadrilateral axisymmetric ring elements. The relationships between spot diameters of laser beams and maximum values of compressive thermal stresses are derived for various power densities. From these relationships, a critical fracture curve is obtained, and it is compared with the experimental results. (author)

  12. Evaluation of some advanced wheat lines (F7 in normal and drought stress conditions

    Directory of Open Access Journals (Sweden)

    R. Nikseresht

    2016-05-01

    Full Text Available For assessment of drought stress effects on agro characteristics of 30 lines and 6 wheat cultivars and for introducing of drought tolerant and susceptible ones one trial were established using split plot base of randomized complete block design with two replications, main plots were stress and non-stress condition and sub plots contain 30 lines and six wheat cultivars in the check trial, irrigation the farm was done with the normal regime, but in stress trial for germination of seeds and one irrigation in Isfand to the end of rooting the farm was irrigated. Within and end of growth season we measured some agronomic and morphological characters such as yield and its component, height, peduncle length, and etc. Responses of cultivars under stress and non-stress conditions were' different, for example drought stress reduced yield. In spite of this general yield reducing, we found some line, such as 2, 29, 23 had relatively high yield (in tree levels. In order to final evaluate using Factor Analysis, Principal Component, Cluster Analysis .Factor Analysis indicated that four important factors accounted for about 80.245 and 79.624 percent of the total variation among traits in normal and drought stress conditions. With cluster analysis of 36 lines and cultivar using Ward procedure based on Euclidean distance were grouped in 4 distance cluster.

  13. The Impact of Simultaneously Applying Normal Stress and Vibrotactile Stimulation for Feedback of Exteroceptive Information.

    Science.gov (United States)

    Reza Motamedi, M; Otis, Martin; Duchaine, Vincent

    2017-06-01

    Commercially available prosthetic hands do not convey any tactile information, forcing amputees to rely solely on visual attention. A promising solution to this problem is haptics, which could lead to new prostheses in which tactile information is conveyed between the amputee and the artificial limb. However, the haptic feedback must be optimized so that amputees can use it effectively; and although several studies have examined how specific haptic feedback systems can transmit certain types of tactile information, there has not yet been much research on the effects of superposing two or more types of feedback at the same location, which might prove to be more effective than using a single type of feedback alone. This paper investigates how the simultaneous application of two different types of haptic feedback-vibration and normal stress-impacts the human sensory perception of each separate feedback type. These stimuli were applied to glabrous skin on the forearms of 14 participants. Our experiments tested whether participants experienced more accurate sensory perception, compared to vibration or normal stress alone, when vibration was applied at the same time as the normal stress, at either the same location, or at a different location 6 cm away. Results indicate that although participants' perception of the normal stress diminished when vibration was applied at the same location, the same combination improved their perception of the vibration. Apparently, vibration has a negative impact upon the ability to perceive normal stress, whether applied at the same or a different location; whereas the opposite is true for the effect of normal stress upon the perception of vibration.

  14. D1 receptors regulate dendritic morphology in normal and stressed prelimbic cortex.

    Science.gov (United States)

    Lin, Grant L; Borders, Candace B; Lundewall, Leslie J; Wellman, Cara L

    2015-01-01

    Both stress and dysfunction of prefrontal cortex are linked to psychological disorders, and structure and function of medial prefrontal cortex (mPFC) are altered by stress. Chronic restraint stress causes dendritic retraction in the prelimbic region (PL) of mPFC in rats. Dopamine release in mPFC increases during stress, and chronic administration of dopaminergic agonists results in dendritic remodeling. Thus, stress-induced alterations in dopaminergic transmission in PL may contribute to dendritic remodeling. We examined the effects of dopamine D1 receptor (D1R) blockade in PL during daily restraint stress on dendritic morphology in PL. Rats either underwent daily restraint stress (3h/day, 10 days) or remained unstressed. In each group, rats received daily infusions of either the D1R antagonist SCH23390 or vehicle into PL prior to restraint; unstressed and stressed rats that had not undergone surgery were also examined. On the final day of restraint, rats were euthanized and brains were processed for Golgi histology. Pyramidal neurons in PL were reconstructed and dendritic morphology was quantified. Vehicle-infused stressed rats demonstrated dendritic retraction compared to unstressed rats, and D1R blockade in PL prevented this effect. Moreover, in unstressed rats, D1R blockade produced dendritic retraction. These effects were not due to attenuation of the HPA axis response to acute stress: plasma corticosterone levels in a separate group of rats that underwent acute restraint stress with or without D1R blockade were not significantly different. These findings indicate that dopaminergic transmission in mPFC during stress contributes directly to the stress-induced retraction of apical dendrites, while dopamine transmission in the absence of stress is important in maintaining normal dendritic morphology. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Sequential path analysis for determining interrelationships between yield and related traits in tobacco (Nicotiana tabacum L. under normal and abiotic stress conditions

    Directory of Open Access Journals (Sweden)

    Bayat Mahdi

    2014-01-01

    Full Text Available In the present work the relationships between yield and its related traits were investigated in tobacco genotypes under normal and abiotic stress conditions (Orobanche aegyptiaca weed at Urmia Tobacco Research Centre, Iran, during 2006-2009 cropping seasons. The experimental design was a randomized complete block design (RCBD with three replications in each condition every year. Analysis of variance revealed extent genetic variability among the genotypes for most of the traits studied. In comparison with normal condition, the mean value of studied traits decreased in stress condition. LAI and FD showed the maximum and minimum diminution in the mean values under stress condition compared to normal one so known as more sensitive and more tolerant traits, respectively. Based on CV values, the traits FD and DLYP showed the minimum and maximum variation among traits in both normal and stress conditions. Correlation analysis revealed significant and positive correlations between DLYP with all studied traits in both normal and stress conditions. Path analysis detected the traits including biomass, APDW and DWR as the first-order variables at normal condition and biomass, APDW, DWR and harvest index as the first-order variables under abiotic stress condition. Based on results, the traits such as biomass, APDW, DWR detected as more important factors in both conditions can be used in tobacco breeding programs for increasing yield. Abbreviation: aerial part fresh weight without leaves weight (APFW, aerial part dry weight without leaves weight (APDW, biomass (BIO, coefficient of variation (CV, dry weight of root (DWR, flowering date (FD, fresh weight of leaf (FWL, fresh weight of root (FWR, harvest index (HI, leaf area index (LAI, dry leaf yield per plant (DLYP, number of leaf (NL, plant height (PH, randomized complete block design (RCBD, standard deviation (Std.

  16. Prognostic significance of normal quantitative planar thallium-201 stress scintigraphy in patients with chest pain

    International Nuclear Information System (INIS)

    Wackers, F.J.; Russo, D.J.; Russo, D.; Clements, J.P.

    1985-01-01

    The prognostic significance of normal quantitative planar thallium-201 stress scintigraphy was evaluated in patients with a chest pain syndrome. The prevalence of cardiac events during follow-up was related to the pretest (that is, before stress scintigraphy) likelihood of coronary artery disease determined on the basis of symptoms, age, sex and stress electrocardiography. In a consecutive series of 344 patients who had adequate thallium-201 stress scintigrams, 95 had unequivocally normal studies by quantitative analysis. The pretest likelihood of coronary artery disease in the 95 patients had a bimodal distribution. During a mean follow-up period of 22 +/- 3 months, no patient died. Three patients (3%) had a cardiac event: two of these patients (pretest likelihood of coronary artery disease 54 and 94%) had a nonfatal myocardial infarction 8 and 22 months, respectively, after stress scintigraphy, and one patient (pretest likelihood 98%) underwent percutaneous transluminal coronary angioplasty 16 months after stress scintigraphy for persisting anginal complaints. Three patients were lost to follow-up; all three had a low pretest likelihood of coronary artery disease. It is concluded that patients with chest pain and normal findings on quantitative thallium-201 scintigraphy have an excellent prognosis. Cardiac events are rare (infarction rate 1% per year) and occur in patients with a moderate to high pretest likelihood of coronary artery disease

  17. Evolution of normal stress and surface roughness in buckled thin films

    NARCIS (Netherlands)

    Palasantzas, G; De Hosson, JTM

    2003-01-01

    In this work we investigate buckling of compressed elastic thin films, which are bonded onto a viscous layer of finite thickness. It is found that the normal stress exerted by the viscous layer on the elastic film evolves with time showing a minimum at early buckling stages, while it increases at

  18. On the normal stress effect in grease-lubricated bearing seals

    NARCIS (Netherlands)

    Baart, P.; Lugt, Pieter Martin; Prakash, B.

    2014-01-01

    The film formation in lip seals, due to the non-Newtonian rheology of the lubricant, has been a topic of speculation. Earlier work suggests that normal stresses in grease would be favorable for the film buildup between the seal lip and shaft or bearing ring. In the current article, we evaluate this

  19. Cylindrical shell under impact load including transverse shear and normal stress

    International Nuclear Information System (INIS)

    Shakeri, M.; Eslami, M.R.; Ghassaa, M.; Ohadi, A.R.

    1993-01-01

    The general governing equations of shell of revolution under shock loads are reduced to equations describing the elastic behavior of cylindrical shell under axisymmetric impact load. The effect of lateral normal stress, transverse shear, and rotary inertia are included, and the equations are solved by Galerkin finite element method. The results are compared with the previous works of authors. (author)

  20. To reduce the maximum stress and the stress shielding effect around a dental implant-bone interface using radial functionally graded biomaterials.

    Science.gov (United States)

    Asgharzadeh Shirazi, H; Ayatollahi, M R; Asnafi, A

    2017-05-01

    In a dental implant system, the value of stress and its distribution plays a pivotal role on the strength, durability and life of the implant-bone system. A typical implant consists of a Titanium core and a thin layer of biocompatible material such as the hydroxyapatite. This coating has a wide range of clinical applications in orthopedics and dentistry due to its biocompatibility and bioactivity characteristics. Low bonding strength and sudden variation of mechanical properties between the coating and the metallic layers are the main disadvantages of such common implants. To overcome these problems, a radial distributed functionally graded biomaterial (FGBM) was proposed in this paper and the effect of material property on the stress distribution around the dental implant-bone interface was studied. A three-dimensional finite element simulation was used to illustrate how the use of radial FGBM dental implant can reduce the maximum von Mises stress and, also the stress shielding effect in both the cortical and cancellous bones. The results, of course, give anybody an idea about optimized behaviors that can be achieved using such materials. The finite element solver was validated by familiar methods and the results were compared to previous works in the literature.

  1. Normalizing the maximum permissible seal failure of the fuel cladding of VVER and the activity of the fission products in the coolant

    International Nuclear Information System (INIS)

    Luzanova, L.M.; Miglo, V.N.; Slavyagin, P.D.

    1993-01-01

    In most countries developing a nuclear power industry based on pressurized water reactors, one of the conditions for issuing a license under normal operating conditions for issuing a license stipulates that the fuel elements may not lose their hermetic seal either under normal operating conditions or during presumable disturbances of the conditions of normal use. At a conference on radiation safety the ALARA principle was taken to be fundamental, it being attempted to keep the activity of the coolant of the primary circuit, including the fission products emerging from unsealed fuel elements, to a level as low as reasonably possible. As many years of experience in the nuclear power industry have shown, nuclear power stations are in many cases operated with nonhermetic fuel elements in the core. Therefore, from the point of view of safety and economy, the best way to operate a power plant is to try to ensure maximum burnup of the fuel of the unsealed elements as they operate within the limits of safe activity of the fission products in the fuel circuits

  2. Application of the newly developed Japanese adenosine normal database for adenosine stress myocardial scintigraphy.

    Science.gov (United States)

    Harata, Shingo; Isobe, Satoshi; Morishima, Itsuro; Suzuki, Susumu; Tsuboi, Hideyuki; Sone, Takahito; Ishii, Hideki; Murohara, Toyoaki

    2015-10-01

    The currently available Japanese normal database (NDB) in stress myocardial perfusion scintigraphy recommended by the Japanese Society of Nuclear Medicine (JSNM-NDB) is created based on the data from exercise tests. The newly developed adenosine normal database (ADS-NDB) remains to be validated for patients undergoing adenosine stress test. We tested whether the diagnostic accuracy of adenosine stress test is improved by the use of ADS-NDB (Kanazawa University). Of 233 consecutive patients undergoing (99m)Tc-MIBI adenosine stress test, 112 patients were tested. The stress/rest myocardial (99m)Tc-MIBI single-photon emission computed tomography (SPECT) images were analyzed by AutoQUANT 7.2 with both ADS-NDB and JSNM-NDB. The summed stress score (SSS) and summed difference score (SDS) were calculated. The agreements of the post-stress defect severity between ADS-NDB and JSNM-NDB were assessed using a weighted kappa statistic. In all patients, mean SSSs of all, right coronary artery (RCA), left anterior descending (LAD), and left circumflex (LCx) territories were significantly lower with ADS-NDB than those with JSNM-NDB. Mean SDSs in all, RCA, and LAD territories were significantly lower with ADS-NDB than those with JSNM-NDB. In 28 patients with significant coronary stenosis, the mean SSS in the RCA territory was significantly lower with ADS-NDB than that with JSNM-NDB. In 84 patients without ischemia, both mean SSSs and SDSs in all, RCA, LAD, and LCx territories were significantly lower with ADS-NDB than those with JSNM-NDB. Weighted kappa values of all patients, patients with significant stenosis, and patients without ischemia were 0.89, 0.83, and 0.92, respectively. Differences were observed between results from ADS-NDB and JSNM-NDB. The diagnostic accuracy of adenosine stress myocardial perfusion scintigraphy may be improved by reducing false-positive results.

  3. Immunohistochemical analysis of oxidative stress and DNA repair proteins in normal mammary and breast cancer tissues

    International Nuclear Information System (INIS)

    Curtis, Carol D; Thorngren, Daniel L; Nardulli, Ann M

    2010-01-01

    During the course of normal cellular metabolism, oxygen is consumed and reactive oxygen species (ROS) are produced. If not effectively dissipated, ROS can accumulate and damage resident proteins, lipids, and DNA. Enzymes involved in redox regulation and DNA repair dissipate ROS and repair the resulting damage in order to preserve a functional cellular environment. Because increased ROS accumulation and/or unrepaired DNA damage can lead to initiation and progression of cancer and we had identified a number of oxidative stress and DNA repair proteins that influence estrogen responsiveness of MCF-7 breast cancer cells, it seemed possible that these proteins might be differentially expressed in normal mammary tissue, benign hyperplasia (BH), ductal carcinoma in situ (DCIS) and invasive breast cancer (IBC). Immunohistochemistry was used to examine the expression of a number of oxidative stress proteins, DNA repair proteins, and damage markers in 60 human mammary tissues which were classified as BH, DCIS or IBC. The relative mean intensity was determined for each tissue section and ANOVA was used to detect statistical differences in the relative expression of BH, DCIS and IBC compared to normal mammary tissue. We found that a number of these proteins were overexpressed and that the cellular localization was altered in human breast cancer tissue. Our studies suggest that oxidative stress and DNA repair proteins not only protect normal cells from the damaging effects of ROS, but may also promote survival of mammary tumor cells

  4. Padé approximant for normal stress differences in large-amplitude oscillatory shear flow

    Science.gov (United States)

    Poungthong, P.; Saengow, C.; Giacomin, A. J.; Kolitawong, C.; Merger, D.; Wilhelm, M.

    2018-04-01

    Analytical solutions for the normal stress differences in large-amplitude oscillatory shear flow (LAOS), for continuum or molecular models, normally take the inexact form of the first few terms of a series expansion in the shear rate amplitude. Here, we improve the accuracy of these truncated expansions by replacing them with rational functions called Padé approximants. The recent advent of exact solutions in LAOS presents an opportunity to identify accurate and useful Padé approximants. For this identification, we replace the truncated expansion for the corotational Jeffreys fluid with its Padé approximants for the normal stress differences. We uncover the most accurate and useful approximant, the [3,4] approximant, and then test its accuracy against the exact solution [C. Saengow and A. J. Giacomin, "Normal stress differences from Oldroyd 8-constant framework: Exact analytical solution for large-amplitude oscillatory shear flow," Phys. Fluids 29, 121601 (2017)]. We use Ewoldt grids to show the stunning accuracy of our [3,4] approximant in LAOS. We quantify this accuracy with an objective function and then map it onto the Pipkin space. Our two applications illustrate how to use our new approximant reliably. For this, we use the Spriggs relations to generalize our best approximant to multimode, and then, we compare with measurements on molten high-density polyethylene and on dissolved polyisobutylene in isobutylene oligomer.

  5. A pleasant familiar odor influences perceived stress and peripheral nervous system activity during normal aging

    Directory of Open Access Journals (Sweden)

    Pauline eJoussain

    2014-02-01

    Full Text Available Effects of smells on stress have been demonstrated in animals and humans, suggesting that inhaling certain odorants may counteract the negative effects of stress. Because stress plays a key role in cerebral aging, the present study set out to examine whether positive odor effects on perceived stress can be achieved in elderly individuals. To this end, two groups of aged individuals (n=36 women, aged from 55 to 65 years, were tested. The first group was exposed for 5 days to a pleasant and, by end of exposure, familiar odor (exposure odor, whereas the other was exposed to a non-scented control stimulus. Stress and mood states were assessed before and after the 5-day odor exposure period. Psychophysiological markers were also assessed at the end of exposure, in response to the exposure odor and to a new odor. Results revealed that stress on this second exposure was decreased and zygomatic EMG activity was increased specifically in the group previously exposed to the odor (p< 0.05. Taken as a whole, these findings offer a new look at the relationship between perceived stress, olfaction and normal aging, opening up new research perspectives on the effect of olfaction on quality of life and well-being in aged individuals.

  6. Fracture transmissivity as a function of normal and shear stress: first results in Opalinus Clay

    International Nuclear Information System (INIS)

    Cuss, R.J.; Milodowski, A.; Noy, D.J.; Harrington, J.F.

    2010-01-01

    Document available in extended abstract form only. Rock-mass failure around openings is usually observed in the form of a highly complex fracture network (EDZ), which is heterogeneous in distribution around a circular tunnel opening because of the heterogeneous stress distribution. The orientation of stress with respect to the fracture network is known to be important. The complex heterogeneous stress trajectory and heterogeneous fracture network results in a broad range of stresses and stress directions acting on the open fracture network. During the open stage of a repository, stress will slowly alter as shear movements occur along the fractures, as well as other time-dependent phenomena. As the repository is back filled, the stress field is further altered as the backfill settles and changes volume because of re-saturation. Therefore, a complex and wide ranging stress regime and stress history will result. In a purely mechanical sense, fracture transmissivity is a function of normal stress, shear stress, and fracture aperture. The Selfrac test from Mont Terri showed the change in transmissivity with effective normal stress. This work showed that fracture transmissivity decreased with increasing normal load and that an effective normal stress of 2.5 MPa is sufficient to yield a transmissivity similar to that seen in intact Opalinus clay (OPA). Therefore fracture closure because of normal stresses has been proven to be a quite efficient mechanism in OPA. A new shear rig was designed to investigate the detail of fracture transmissivity in OPA. The experimental configuration uses two prepared blocks that are 60 x 60 mm in size and approximately 20 mm thick. The first test sample had machine ground surfaces in contact with each other, with pore fluid being delivered through the centre of the top block directly to the fracture surface. The experimental programme included two distinct stages. In the first normal load was altered to investigate fracture transmissivity

  7. 19 mm sized bileaflet valve prostheses' flow field investigated by bidimensional laser Doppler anemometry (part II: maximum turbulent shear stresses)

    Science.gov (United States)

    Barbaro, V; Grigioni, M; Daniele, C; D'Avenio, G; Boccanera, G

    1997-11-01

    The investigation of the flow field generated by cardiac valve prostheses is a necessary task to gain knowledge on the possible relationship between turbulence-derived stresses and the hemolytic and thrombogenic complications in patients after valve replacement. The study of turbulence flows downstream of cardiac prostheses, in literature, especially concerns large-sized prostheses with a variable flow regime from very low up to 6 L/min. The Food and Drug Administration draft guidance requires the study of the minimum prosthetic size at a high cardiac output to reach the maximum Reynolds number conditions. Within the framework of a national research project regarding the characterization of cardiovascular endoprostheses, an in-depth study of turbulence generated downstream of bileaflet cardiac valves is currently under way at the Laboratory of Biomedical Engineering of the Istituto Superiore di Sanita. Four models of 19 mm bileaflet valve prostheses were used: St Jude Medical HP, Edwards Tekna, Sorin Bicarbon, and CarboMedics. The prostheses were selected for the nominal Tissue Annulus Diameter as reported by manufacturers without any assessment of valve sizing method, and were mounted in aortic position. The aortic geometry was scaled for 19 mm prostheses using angiographic data. The turbulence-derived shear stresses were investigated very close to the valve (0.35 D0), using a bidimensional Laser Doppler anemometry system and applying the Principal Stress Analysis. Results concern typical turbulence quantities during a 50 ms window at peak flow in the systolic phase. Conclusions are drawn regarding the turbulence associated to valve design features, as well as the possible damage to blood constituents.

  8. Fracture predictions for cracks exposed to superimposed normal and shear stresses

    International Nuclear Information System (INIS)

    Richard, H.A.

    1985-01-01

    The author developed a special device and a fracture mechanics specimen and proposed a procedure for determining the fracture toughness when Mixed Mode and Mode II stresses are applied. This device makes it possible to generate pure normal stresses, superimposed normal and shearing stresses as well as pure shearing stresses in the cross section of the crack in the specimen, as desired. The so-called CTS fracture mechanics specimen has an edge crack. The load is transferred statically determind from the device to the specimen by means of six studs altogether. The experiments described, which were carried out with specimens made of the brittle materials PMMA (Plexiglas) and Araldit B, clearly show that it is possible to evaluate the validity of the individual fracture hypotheses by suitable experiments. It is also found that the fracture behaviour of different materials varies considerably both in quality and quantity. In conclusion, a practice-oriented fracture criterion is indicated which enables a practice-conforming evaluation of Mixed-Mode crack problems, as is shown by way of examples. (orig./HP) [de

  9. The influence of normal fault on initial state of stress in rock mass

    Directory of Open Access Journals (Sweden)

    Tajduś Antoni

    2016-03-01

    Full Text Available Determination of original state of stress in rock mass is a very difficult task for rock mechanics. Yet, original state of stress in rock mass has fundamental influence on secondary state of stress, which occurs in the vicinity of mining headings. This, in turn, is the cause of the occurrence of a number of mining hazards, i.e., seismic events, rock bursts, gas and rock outbursts, falls of roof. From experience, it is known that original state of stress depends a lot on tectonic disturbances, i.e., faults and folds. In the area of faults, a great number of seismic events occur, often of high energies. These seismic events, in many cases, are the cause of rock bursts and damage to the constructions located inside the rock mass and on the surface of the ground. To estimate the influence of fault existence on the disturbance of original state of stress in rock mass, numerical calculations were done by means of Finite Element Method. In the calculations, it was tried to determine the influence of different factors on state of stress, which occurs in the vicinity of a normal fault, i.e., the influence of normal fault inclination, deformability of rock mass, values of friction coefficient on the fault contact. Critical value of friction coefficient was also determined, when mutual dislocation of rock mass part separated by a fault is impossible. The obtained results enabled formulation of a number of conclusions, which are important in the context of seismic events and rock bursts in the area of faults.

  10. The influence of normal fault on initial state of stress in rock mass

    Science.gov (United States)

    Tajduś, Antoni; Cała, Marek; Tajduś, Krzysztof

    2016-03-01

    Determination of original state of stress in rock mass is a very difficult task for rock mechanics. Yet, original state of stress in rock mass has fundamental influence on secondary state of stress, which occurs in the vicinity of mining headings. This, in turn, is the cause of the occurrence of a number of mining hazards, i.e., seismic events, rock bursts, gas and rock outbursts, falls of roof. From experience, it is known that original state of stress depends a lot on tectonic disturbances, i.e., faults and folds. In the area of faults, a great number of seismic events occur, often of high energies. These seismic events, in many cases, are the cause of rock bursts and damage to the constructions located inside the rock mass and on the surface of the ground. To estimate the influence of fault existence on the disturbance of original state of stress in rock mass, numerical calculations were done by means of Finite Element Method. In the calculations, it was tried to determine the influence of different factors on state of stress, which occurs in the vicinity of a normal fault, i.e., the influence of normal fault inclination, deformability of rock mass, values of friction coefficient on the fault contact. Critical value of friction coefficient was also determined, when mutual dislocation of rock mass part separated by a fault is impossible. The obtained results enabled formulation of a number of conclusions, which are important in the context of seismic events and rock bursts in the area of faults.

  11. Software for determining the direction of movement, shear and normal stresses of a fault under a determined stress state

    Science.gov (United States)

    Álvarez del Castillo, Alejandra; Alaniz-Álvarez, Susana Alicia; Nieto-Samaniego, Angel Francisco; Xu, Shunshan; Ochoa-González, Gil Humberto; Velasquillo-Martínez, Luis Germán

    2017-07-01

    In the oil, gas and geothermal industry, the extraction or the input of fluids induces changes in the stress field of the reservoir, if the in-situ stress state of a fault plane is sufficiently disturbed, a fault may slip and can trigger fluid leakage or the reservoir might fracture and become damaged. The goal of the SSLIPO 1.0 software is to obtain data that can reduce the risk of affecting the stability of wellbores. The input data are the magnitudes of the three principal stresses and their orientation in geographic coordinates. The output data are the slip direction of a fracture in geographic coordinates, and its normal (σn) and shear (τ) stresses resolved on a single or multiple fracture planes. With this information, it is possible to calculate the slip tendency (τ/σn) and the propensity to open a fracture that is inversely proportional to σn. This software could analyze any compressional stress system, even non-Andersonian. An example is given from an oilfield in southern Mexico, in a region that contains fractures formed in three events of deformation. In the example SSLIPO 1.0 was used to determine in which deformation event the oil migrated. SSLIPO 1.0 is an open code application developed in MATLAB. The URL to obtain the source code and to download SSLIPO 1.0 are: http://www.geociencias.unam.mx/ alaniz/main_code.txt, http://www.geociencias.unam.mx/ alaniz/ SSLIPO_pkg.exe.

  12. Extreme warmth and heat-stressed plankton in the tropics during the Paleocene-Eocene Thermal Maximum.

    Science.gov (United States)

    Frieling, Joost; Gebhardt, Holger; Huber, Matthew; Adekeye, Olabisi A; Akande, Samuel O; Reichart, Gert-Jan; Middelburg, Jack J; Schouten, Stefan; Sluijs, Appy

    2017-03-01

    Global ocean temperatures rapidly warmed by ~5°C during the Paleocene-Eocene Thermal Maximum (PETM; ~56 million years ago). Extratropical sea surface temperatures (SSTs) met or exceeded modern subtropical values. With these warm extratropical temperatures, climate models predict tropical SSTs >35°C-near upper physiological temperature limits for many organisms. However, few data are available to test these projected extreme tropical temperatures or their potential lethality. We identify the PETM in a shallow marine sedimentary section deposited in Nigeria. On the basis of planktonic foraminiferal Mg/Ca and oxygen isotope ratios and the molecular proxy [Formula: see text], latest Paleocene equatorial SSTs were ~33°C, and [Formula: see text] indicates that SSTs rose to >36°C during the PETM. This confirms model predictions on the magnitude of polar amplification and refutes the tropical thermostat theory. We attribute a massive drop in dinoflagellate abundance and diversity at peak warmth to thermal stress, showing that the base of tropical food webs is vulnerable to rapid warming.

  13. Protection from intracellular oxidative stress by cytoglobin in normal and cancerous oesophageal cells.

    Directory of Open Access Journals (Sweden)

    Fiona E McRonald

    Full Text Available Cytoglobin is an intracellular globin of unknown function that is expressed mostly in cells of a myofibroblast lineage. Possible functions of cytoglobin include buffering of intracellular oxygen and detoxification of reactive oxygen species. Previous work in our laboratory has demonstrated that cytoglobin affords protection from oxidant-induced DNA damage when over expressed in vitro, but the importance of this in more physiologically relevant models of disease is unknown. Cytoglobin is a candidate for the tylosis with oesophageal cancer gene, and its expression is strongly down-regulated in non-cancerous oesophageal biopsies from patients with TOC compared with normal biopsies. Therefore, oesophageal cells provide an ideal experimental model to test our hypothesis that downregulation of cytoglobin expression sensitises cells to the damaging effects of reactive oxygen species, particularly oxidative DNA damage, and that this could potentially contribute to the TOC phenotype. In the current study, we tested this hypothesis by manipulating cytoglobin expression in both normal and oesophageal cancer cell lines, which have normal physiological and no expression of cytoglobin respectively. Our results show that, in agreement with previous findings, over expression of cytoglobin in cancer cell lines afforded protection from chemically-induced oxidative stress but this was only observed at non-physiological concentrations of cytoglobin. In addition, down regulation of cytoglobin in normal oesophageal cells had no effect on their sensitivity to oxidative stress as assessed by a number of end points. We therefore conclude that normal physiological concentrations of cytoglobin do not offer cytoprotection from reactive oxygen species, at least in the current experimental model.

  14. Comparison of oxidative stress in preeclampsia, normal pregnancy and non-pregnant women

    Directory of Open Access Journals (Sweden)

    A. Ghazavi

    2006-11-01

    Full Text Available Introduction: Preeclampsia is a pregnancy-specific condition characterized by hypertension and proteinuria. Preeclampsia remains a disease of theories as its real etiology has remained elusive. Endothelial cell dysfunction may play a role in the pathobiology of preeclampsia. There is some evidence to suggest that endothelial cell damage result from oxidative stress. The aim of the study was to measure oxidative stress markers in preeclampsia. Material and Methods: Total antioxidant capacity (TAC, lipid peroxidation (LPO and thiol groups was measured in 20 women with preeclampsia, 20 normal pregnant women and 20 nonpregnant women. All three women groups were matched with respect to age, BMI, parity and gestational age. Oxidative stress markers were measured by spectrophotometer methods. Results: Serum concentration of LPO was significantly higher in preeclampsia (17.7 + 3.8 nmol/ml as compared with nonpregnant women (10.4 + 0.48 nmol/ml, p< 0.0001. TAC in preeclamptic women was lower than those in normal pregnant and non-pregnant women, but not statistically significantly. There was no significant difference between the mean concentrations of thiol groups in the women groups. Conclusion: Increased levels of LPO products may cause peroxidative damage of vascular endothelium and result in clinical symptoms of preeclampsia. However, further experimental and clinical studies are necessary to clarify the pathogenesis of preeclampsia.

  15. Mechanical stress analysis for a fuel rod under normal operating conditions

    International Nuclear Information System (INIS)

    Pino, Eddy S.; Giovedi, Claudia; Serra, Andre da Silva; Abe, Alfredo Y.

    2013-01-01

    Nuclear reactor fuel elements consist mainly in a system of a nuclear fuel encapsulated by a cladding material subject to high fluxes of energetic neutrons, high operating temperatures, pressure systems, thermal gradients, heat fluxes and with chemical compatibility with the reactor coolant. The design of a nuclear reactor requires, among a set of activities, the evaluation of the structural integrity of the fuel rod submitted to different loads acting on the fuel rod and the specific properties (dimensions and mechanical and thermal properties) of the cladding material and coolant, including thermal and pressure gradients produced inside the rod due to the fuel burnup. In this work were evaluated the structural mechanical stresses of a fuel rod using stainless steel as cladding material and UO 2 with a low degree of enrichment as fuel pellet on a PWR (pressurized water reactor) under normal operating conditions. In this sense, tangential, radial and axial stress on internal and external cladding surfaces considering the orientations of 0 deg, 90 deg and 180 deg were considered. The obtained values were compared with the limit values for stress to the studied material. From the obtained results, it was possible to conclude that, under the expected normal reactor operation conditions, the integrity of the fuel rod can be maintained. (author)

  16. Differential effects of mental stress on plasma homovanillic acid in schizophrenia and normal controls.

    Science.gov (United States)

    Sumiyoshi, T; Saitoh, O; Yotsutsuji, T; Itoh, H; Kurokawa, K; Kurachi, M

    1999-04-01

    We previously reported that mental stress by Kraepelin's arithmetic test decreases plasma homovanillic acid (pHVA) levels in psychiatrically normal healthy human subjects. The present study was undertaken to determine whether this pattern of changes in pHVA concentrations resulting from mental stress is altered in patients with schizophrenia. Fourteen male patients with schizophrenia including those under ongoing neuroleptic treatment and 14 normal male volunteers participated in the study. Following overnight fast and restricted physical activity, the subjects performed Kraepelin's arithmetic test for 30 minutes. Plasma samples were collected immediately before and after the test for measurement of pHVA levels. A significant diagnosis by Kraepelin's test effect was observed due to a decrease in pHVA levels by the Kraepelin test in control subjects but not in patients with schizophrenia. Changes in pHVA levels during the Kraepelin test positively correlated with pre-test pHVA levels in control subjects, while this correlation was not observed in patients with schizophrenia. These results may be further support for the presence of a dopamine-dependent restitutive system in the brain. The absence of response of pHVA levels to mental stress in patients with schizophrenia may indicate that the dopamine restitutive system in these patients is disrupted or already down-regulated, as previously predicted.

  17. The Comparison of Hardiness and Coping Styles with Psychological Stress in Addicted and Normal People

    Directory of Open Access Journals (Sweden)

    Rahim Molazadeh, E

    2011-05-01

    Full Text Available Introduction: The purpose of this study was to compare the hardiness and coping styles with stress in addicted and normal people in the city of Rasht. Method: The method of this study was causal comparative research. In sampling one hundred addicts were selected by multistage cluster sampling and one hundred normal ones selected by available sampling, then the Kobasa personal views survey and Moos and Billings coping styles questionnaires were administered among both groups. The Pearson correlation coefficients, independent samples t-test and regression analysis were used for data analysis. Results: The results showed that there were significant differences between the mean scores of hardiness and emotion focused coping style in addicted and normal people, but there was no significant difference on problem focused coping style. Regression analysis also showed that hardiness can be a significant predictor for emotion focused coping style. Conclusion: The findings of this research show the important role of some of the personality characteristics such as hardiness and coping styles with stress that may correlate with the tendency to addiction and substance abuse in people.

  18. High coronary artery calcium score affects clinical outcome despite normal stress myocardial perfusion imaging and normal left ventricular ejection fraction

    DEFF Research Database (Denmark)

    Madsen, Claus Juul; Andersen, Kim F; Zerahn, Bo

    2013-01-01

    Normal myocardial perfusion imaging (MPI) indicates a low risk for cardiac death and new ischaemic events. However, the impact of normal MPI combined with a high coronary artery calcium score (CACS) is not clear. The aims of this study were to evaluate the risk of severely elevated CACS and to id......Normal myocardial perfusion imaging (MPI) indicates a low risk for cardiac death and new ischaemic events. However, the impact of normal MPI combined with a high coronary artery calcium score (CACS) is not clear. The aims of this study were to evaluate the risk of severely elevated CACS...

  19. Rigid MATLAB drivetrain model of a 500 kW wind turbine for predicting maximum gear tooth stresses in a planetary gearbox using multibody gear constraints

    DEFF Research Database (Denmark)

    Jørgensen, Martin Felix; Pedersen, Niels Leergaard; Sørensen, Jens Nørkær

    2014-01-01

    multiple planetary gears are not taken into account. Finite Element Method (FEM) calculations show that when the wind turbine runs close to the maximum wind speed, the maximum gear tooth stress is in the range of 500–700 MPa, which is considered to be realistic using a “worst-case” method. The presented...... for not only transferring torque but also for calculating the gear tooth and internal body reaction forces. The method is appropriate for predicting gear tooth stresses without considering all the complexity of gear tooth geometries. This means that, e.g. gear tooth load-sharing and load-distribution among...

  20. Normally closed microgrippers using a highly stressed diamond-like carbon and Ni bimorph structure

    Science.gov (United States)

    Luo, J. K.; Flewitt, A. J.; Spearing, S. M.; Fleck, N. A.; Milne, W. I.

    2004-12-01

    A normally closed microgripper with a radius of curvature of 18-50 μm using a diamond-like carbon (DLC) and stress free electroplated Ni bimorph structure has been demonstrated. The large curvature in the fingers of the microgrippers is due to the high compressive stress of the DLC layer. The radius of curvature of the figures can be adjusted by the thickness ratio, and the closure of the devices can also be adjusted by varying the finger length. This device works much more efficiently than other bimorph structures due to the large difference in thermal expansion coefficients between the DLC and the Ni layers. Preliminary electrical tests have shown these microgrippers can be opened by 60°-90° at an applied power of <20mW.

  1. Numerical predictions and measurements of Reynolds normal stresses in turbulent pipe flow of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Resende, P.R. [Centro de Estudos de Fenomenos de Transporte, DEMEGI, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto (Portugal)]. E-mail: resende@fe.up.pt; Escudier, M.P. [Department of Engineering, University of Liverpool, Brownlow Street, Liverpool L69 3GH (United Kingdom)]. E-mail: escudier@liv.ac.uk; Presti, F [Department of Engineering, University of Liverpool, Brownlow Street, Liverpool L69 3GH (United Kingdom); Pinho, F.T. [Centro de Estudos de Fenomenos de Transporte, DEM, Universidade do Minho Campus de Azurem, 4800-058 Guimaraes (Portugal)]. E-mail: fpinho@dem.uminho.pt; Cruz, D.O.A. [Departamento de Engenharia Mecanica, Universidade Federal do Para-UFPa Campus Universitario do Guama, 66075-900 Belem, Para (Brazil)]. E-mail: doac@ufpa.br

    2006-04-15

    An anisotropic low Reynolds number k-{epsilon} turbulence model has been developed and its performance compared with experimental data for fully-developed turbulent pipe flow of four different polymer solutions. Although the predictions of friction factor, mean velocity and turbulent kinetic energy show only slight improvements over those of a previous isotropic model [Cruz, D.O.A., Pinho, F.T., Resende, P.R., 2004. Modeling the new stress for improved drag reduction predictions of viscoelastic pipe flow. J. Non-Newt. Fluid Mech. 121, 127-141], the new turbulence model is capable of predicting the enhanced anisotropy of the Reynolds normal stresses that accompanies polymer drag reduction in turbulent flow.

  2. Numerical predictions and measurements of Reynolds normal stresses in turbulent pipe flow of polymers

    International Nuclear Information System (INIS)

    Resende, P.R.; Escudier, M.P.; Presti, F; Pinho, F.T.; Cruz, D.O.A.

    2006-01-01

    An anisotropic low Reynolds number k-ε turbulence model has been developed and its performance compared with experimental data for fully-developed turbulent pipe flow of four different polymer solutions. Although the predictions of friction factor, mean velocity and turbulent kinetic energy show only slight improvements over those of a previous isotropic model [Cruz, D.O.A., Pinho, F.T., Resende, P.R., 2004. Modeling the new stress for improved drag reduction predictions of viscoelastic pipe flow. J. Non-Newt. Fluid Mech. 121, 127-141], the new turbulence model is capable of predicting the enhanced anisotropy of the Reynolds normal stresses that accompanies polymer drag reduction in turbulent flow

  3. Activation of ATP-sensitive potassium channel by iptakalim normalizes stress-induced HPA axis disorder and depressive behaviour by alleviating inflammation and oxidative stress in mouse hypothalamus.

    Science.gov (United States)

    Zhao, Xiao-Jie; Zhao, Zhan; Yang, Dan-Dan; Cao, Lu-Lu; Zhang, Ling; Ji, Juan; Gu, Jun; Huang, Ji-Ye; Sun, Xiu-Lan

    2017-04-01

    Stress-induced disturbance of the hypothalamic-pituitary-adrenal (HPA) axis is strongly implicated in incidence of mood disorders. A heightened neuroinflammatory response and oxidative stress play a fundamental role in the dysfunction of the HPA axis. We have previously demonstrated that iptakalim (Ipt), a new ATP-sensitive potassium (K-ATP) channel opener, could prevent oxidative injury and neuroinflammation against multiple stimuli-induced brain injury. The present study was to demonstrate the impacts of Ipt in stress-induced HPA axis disorder and depressive behavior. We employed 2 stress paradigms: 8 weeks of continuous restraint stress (chronic restraint stress, CRS) and 2h of restraint stress (acute restraint stress, ARS), to mimic both chronic stress and severe acute stress. Prolonged (4 weeks) and short-term (a single injection) Ipt treatment was administered 30min before each stress paradigm. We found that HPA axis was altered after stress, with different responses to CRS (lower ACTH and CORT, higher AVP, but normal CRH) and ARS (higher CRH, ACTH and CORT, but normal AVP). Both prolonged and short-term Ipt treatment normalized stress-induced HPA axis disorders and abnormal behaviors in mice. CRS and ARS up-regulated mRNA levels of inflammation-related molecules (TNFα, IL-1β, IL-6 and TLR4) and oxidative stress molecules (gp91phox, iNOS and Nrf2) in the mouse hypothalamus. Double immunofluorescence showed CRS and ARS increased microglia activation (CD11b and TNFα) and oxidative stress in neurons (NeuN and gp91phox), which were alleviated by Ipt. Therefore, the present study reveals that Ipt could prevent against stress-induced HPA axis disorders and depressive behavior by alleviating inflammation and oxidative stress in the hypothalamus. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Strength evolution of simulated carbonate-bearing faults: The role of normal stress and slip velocity

    Science.gov (United States)

    Mercuri, Marco; Scuderi, Marco Maria; Tesei, Telemaco; Carminati, Eugenio; Collettini, Cristiano

    2018-04-01

    A great number of earthquakes occur within thick carbonate sequences in the shallow crust. At the same time, carbonate fault rocks exhumed from a depth plasticity). We performed friction experiments on water-saturated simulated carbonate-bearing faults for a wide range of normal stresses (from 5 to 120 MPa) and slip velocities (from 0.3 to 100 μm/s). At high normal stresses (σn > 20 MPa) fault gouges undergo strain-weakening, that is more pronounced at slow slip velocities, and causes a significant reduction of frictional strength, from μ = 0.7 to μ = 0.47. Microstructural analysis show that fault gouge weakening is driven by deformation accommodated by cataclasis and pressure-insensitive deformation processes (pressure solution and granular plasticity) that become more efficient at slow slip velocity. The reduction in frictional strength caused by strain weakening behaviour promoted by the activation of pressure-insensitive deformation might play a significant role in carbonate-bearing faults mechanics.

  5. The effect of inertia, viscous damping, temperature and normal stress on chaotic behaviour of the rate and state friction model

    Science.gov (United States)

    Sinha, Nitish; Singh, Arun K.; Singh, Trilok N.

    2018-04-01

    A fundamental understanding of frictional sliding at rock surfaces is of practical importance for nucleation and propagation of earthquakes and rock slope stability. We investigate numerically the effect of different physical parameters such as inertia, viscous damping, temperature and normal stress on the chaotic behaviour of the two state variables rate and state friction (2sRSF) model. In general, a slight variation in any of inertia, viscous damping, temperature and effective normal stress reduces the chaotic behaviour of the sliding system. However, the present study has shown the appearance of chaos for the specific values of normal stress before it disappears again as the normal stress varies further. It is also observed that magnitude of system stiffness at which chaotic motion occurs, is less than the corresponding value of critical stiffness determined by using the linear stability analysis. These results explain the practical observation why chaotic nucleation of an earthquake is a rare phenomenon as reported in literature.

  6. The determination of the first normal stress coefficient of an exopolysaccharide solution by rheo-optical measurements

    NARCIS (Netherlands)

    Zarzycki, R.; Linden, van der E.; Sagis, L.M.C.; Venema, P.; Babuchowski, A.

    2004-01-01

    Abstract This paper illustrates how rheo-optical techniques may be utilized to determine the first normal stress coefficient for an exopolysaccharide (EPS) produced by the Lactobacillus delbrueckii ssp. bulgaricus LY03, which is widely used in yoghurt production. In this technique both shear stress,

  7. Welding-induced local maximum residual stress in heat affected zone of low-carbon austenitic stainless steel with machined surface layer and its influential factors

    International Nuclear Information System (INIS)

    Okano, Shigetaka; Ihara, Ryohei; Kanamaru, Daisuke; Mochizuki, Masahito

    2015-01-01

    In this study, the effects of work-hardening and pre-existing stress in the machined surface layer of low-carbon austenitic stainless steel on the welding-induced residual stress were experimentally investigated through the use of weld specimens with three different surface layers; as-cutout, mechanically-polished and electrolytically-polished. The high tensile and compressive stresses exist in the work-hardened surface layer of the as-cutout and mechanically-polished specimens, respectively. Meanwhile, no stress and work-hardened surface layer exist in the electrolytically-polished specimen. TIG bead-on-plate welding under the same welding heat input conditions was performed to introduce the residual stress into these specimens. Using these welded specimens, the distributions of welding-induced residual stress were measured by the X-ray diffraction method. Similarly, the distributions of hardness in welds were estimated by the Vickers hardness test. And then, these distributions were compared with one another. Based on the results, the residual stress in the weld metal (WM) is completely unaffected by the machined surface layer because the work-hardened surface layer disappears through the processes of melting and solidification during welding. The local maximum longitudinal tensile residual stress in the heat affected zone (HAZ) depends on the work-hardening but not on the existing stress, regardless of whether tensile or compressive, in the machined surface layer before welding. At the base metal far from WM and HAZ, the residual stress is formed by the addition of the welding-induced residual stress to the pre-existing stress in the machined surface layer before welding. The features of the welding-induced residual stress in low-carbon austenitic stainless steel with the machined surface layer and their influential factors were thus clarified. (author)

  8. Numerical estimates of the maximum sustainable pore pressure in anticline formations using the tensor based concept of pore pressure-stress coupling

    Directory of Open Access Journals (Sweden)

    Andreas Eckert

    2015-02-01

    Full Text Available The advanced tensor based concept of pore pressure-stress coupling is used to provide pre-injection analytical estimates of the maximum sustainable pore pressure change, ΔPc, for fluid injection scenarios into generic anticline geometries. The heterogeneous stress distribution for different prevailing stress regimes in combination with the Young's modulus (E contrast between the injection layer and the cap rock and the interbedding friction coefficient, μ, may result in large spatial and directional differences of ΔPc. A single value characterizing the cap rock as for horizontal layered injection scenarios is not obtained. It is observed that a higher Young's modulus in the cap rock and/or a weak mechanical coupling between layers amplifies the maximum and minimum ΔPc values in the valley and limb, respectively. These differences in ΔPc imposed by E and μ are further amplified by different stress regimes. The more compressional the stress regime is, the larger the differences between the maximum and minimum ΔPc values become. The results of this study show that, in general compressional stress regimes yield the largest magnitudes of ΔPc and extensional stress regimes provide the lowest values of ΔPc for anticline formations. Yet this conclusion has to be considered with care when folded anticline layers are characterized by flexural slip and the friction coefficient between layers is low, i.e. μ = 0.1. For such cases of weak mechanical coupling, ΔPc magnitudes may range from 0 MPa to 27 MPa, indicating imminent risk of fault reactivation in the cap rock.

  9. Small average differences in attenuation corrected images between men and women in myocardial perfusion scintigraphy: a novel normal stress database

    International Nuclear Information System (INIS)

    Trägårdh, Elin; Sjöstrand, Karl; Jakobsson, David; Edenbrandt, Lars

    2011-01-01

    The American Society of Nuclear Cardiology and the Society of Nuclear Medicine state that incorporation of attenuation-corrected (AC) images in myocardial perfusion scintigraphy (MPS) will improve image quality, interpretive certainty, and diagnostic accuracy. However, commonly used software packages for MPS usually include normal stress databases for non-attenuation corrected (NC) images but not for attenuation-corrected (AC) images. The aim of the study was to develop and compare different normal stress databases for MPS in relation to NC vs. AC images, male vs. female gender, and presence vs. absence of obesity. The principal hypothesis was that differences in mean count values between men and women would be smaller with AC than NC images, thereby allowing for construction and use of gender-independent AC stress database. Normal stress perfusion databases were developed with data from 126 male and 205 female patients with normal MPS. The following comparisons were performed for all patients and separately for normal weight vs. obese patients: men vs. women for AC; men vs. women for NC; AC vs. NC for men; and AC vs. NC for women. When comparing AC for men vs. women, only minor differences in mean count values were observed, and there were no differences for normal weight vs. obese patients. For all other analyses major differences were found, particularly for the inferior wall. The results support the hypothesis that it is possible to use not only gender independent but also weight independent AC stress databases

  10. The comparison of stress and marital satisfaction status of parents of hearing-impaired and normal children

    Directory of Open Access Journals (Sweden)

    Karim Gharashi

    2013-03-01

    Full Text Available Background and Aim: Stress is the source of many problems in human-kind lives and threatens people's life constantly. Having hearing-impaired child, not only causes stress in parents, but also affects their marital satisfaction. The purpose of this study was comparing the stress and marital satisfaction status between the normal and hearing-impaired children's parents.Methods: This was a causal-comparative study. Eighty parents of normal children and 80 parents of hearing-impaired children were chosen from rehabilitation centers and kindergartens in city of Tabriz, Iran by available and clustering sampling method. All parents were asked to complete the Friedrich's source of stress and Enrich marital satisfaction questionnaires.Results: Parents of hearing-impaired children endure more stress than the normal hearing ones (p<0.001. The marital satisfaction of hearing-impaired children's parents was lower than the parents of normal hearing children, too (p<0.001.Conclusion: Having a hearing-impaired child causes stress and threatens the levels of marital satisfaction. This requires much more attention and a distinct planning for parents of handicap children to reduce their stress.

  11. Stress Echocardiography and Major Cardiac Events in Patients with Normal Exercise Test

    Science.gov (United States)

    Calasans, Flávia Ricci; Santos, Bruno Fernandes de Oliveira; Silveira, Débora Consuelo Rocha; de Araújo, Ana Carla Pereira; Melo, Luiza Dantas; Barreto-Filho, José Augusto; Sousa, Antônio Carlos Sobral; Oliveira, Joselina Luzia Menezes

    2013-01-01

    Background Exercise test (ET) is the preferred initial noninvasive test for the diagnosis and risk stratification of coronary artery disease (CAD), however, its lower sensitivity may fail to identify patients at greater risk of adverse events. Objective To assess the value of stress echocardiography (SE) for predicting all-cause mortality and major cardiac events (MACE) in patients with intermediate pretest probability of CAD and a normal ET. Methods 397 patients with intermediate CAD pretest probability, estimated by the Morise score, and normal ET who underwent SE were studied. The patients were divided into two groups according to the absence (G1) or presence (G2) of myocardial ischemia on SE .End points evaluated were all-cause mortality and MACE, defined as cardiac death and nonfatal acute myocardial infarction (AMI). Results G1 group was comprised of 329 (82.8%) patients. The mean age of the patients was 57.37 ± 11 years and 44.1% were male. During a mean follow-up of 75.94 ± 17.24 months, 13 patients died, three of them due to cardiac causes, and 13 patients suffered nonfatal AMI. Myocardial ischemia remained an independent predictor of MACE (HR 2.49; [CI] 95% 1.74-3.58). The independent predictors for all-cause mortality were male gender (HR 9.83; [CI] 95% 2.15-44.97) and age over 60 years (HR 4.57; [CI] 95% 1.39-15.23). Conclusion Positive SE for myocardial ischemia is a predictor of MACE in the studied sample, which helps to identify a subgroup of patients at higher risk of events despite having normal ET. PMID:23765384

  12. The numerical evaluation of maximum-likelihood estimates of the parameters for a mixture of normal distributions from partially identified samples

    Science.gov (United States)

    Walker, H. F.

    1976-01-01

    Likelihood equations determined by the two types of samples which are necessary conditions for a maximum-likelihood estimate are considered. These equations, suggest certain successive-approximations iterative procedures for obtaining maximum-likelihood estimates. These are generalized steepest ascent (deflected gradient) procedures. It is shown that, with probability 1 as N sub 0 approaches infinity (regardless of the relative sizes of N sub 0 and N sub 1, i=1,...,m), these procedures converge locally to the strongly consistent maximum-likelihood estimates whenever the step size is between 0 and 2. Furthermore, the value of the step size which yields optimal local convergence rates is bounded from below by a number which always lies between 1 and 2.

  13. Effect of Chinese traditional medicine anti-fatigue prescription on the concentration of the serum testosterone and cortisol in male rats under stress of maximum intensive training

    International Nuclear Information System (INIS)

    Dong Ling; Si Xulan

    2008-01-01

    Objective: To study the effect of chinese traditional medicine anti-fatigue prescription on the concentration of the serum testosterone (T) and cortisol (C) in male rats under the stress of maximum intensive training. Methods: Wistar male rat models of stress under maximum intensity training were established (n=40) and half of them were treated with Chinese traditional medicine anti-fatigue prescription twenty undisturbed rats served as controls. Testosterone and cortisol serum levels were determined with RIA at the end of the seven weeks' experiment. Results: Maximum intensive training would cause the level of the serum testosterone lowered, the concentration of the cortisol elevated and the ratio of T/C reduced. The serum T levels and T/C ratio were significantly lower and cortisol levels significantly higher in the untreated models than those in the treated models and controls (P<0.01). The levels of the two hormones were markedly corrected in the treated models with no significantly differences from those in the controls. However, the T/C ratio was still significantly lower than that in the controls (P <0.05) due to a relatively slightly greater degree of reduction of T levels. Conclusion: Anti-fatigue prescription can not only promote the recovery of fatigue after the maximum intensive training but also strengthen the anabolism of the rats. (authors)

  14. Myocardial kinetics of thallium-201 after stress in normal and perfusion-reduced canine myocardium

    International Nuclear Information System (INIS)

    Okada, R.D.

    1985-01-01

    Despite the emerging use of quantitative computer programs for assessing myocardial thallium uptake and clearance after exercise, little is known about the kinetics of thallium after exercise stress. Accordingly, 11 mongrel dogs with experimental left anterior descending coronary stenoses were given thallium during norepinephrine infusion to simulate exercise. The infusion was discontinued and thallium activity was monitored regionally using miniature radiation detectors for 3 hours. Heart rate, arterial pressure and double product all increased significantly during norepinephrine infusion. The mean fractional myocardial thallium clearance was lower (0.47 +/- 0.03 [+/- standard error of the mean]) for the stenosis zone than for the no-stenosis zone (0.57 +/- 0.03) (p less than 0.0001). The stress blood flow ratio (stenosis/no-stenosis zone = 0.27 +/- 0.06) was significantly lower than the final thallium activity ratio (0.68 +/- 0.07) (p less than 0.001), consistent with thallium redistribution occurring over the 3-hour period. Myocardial thallium activity in the stenosis zone peaked in a mean of 2.2 minutes, then washed out biexponentially with a final decay constant of 0.0035 +/- 0.0005 min-1. Myocardial thallium activity in the no-stenosis zone peaked within 1 minute in all dogs, then washed out biexponentially, with a final decay constant of 0.0043 +/- 0.0003 (p less than 0.001 compared with stenosis zone). In conclusion, fractional clearance of thallium can differentiate myocardium distal to a coronary artery stenosis from that supplied by a normal coronary vessel

  15. Prognostic value of normal stress-only myocardial perfusion imaging: a comparison between conventional and CZT-based SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, Shu; Ottervanger, Jan Paul; Timmer, Jorik R. [Isala Hospital, Department of Cardiology, Zwolle (Netherlands); Mouden, Mohamed; Engbers, Elsemiek [Isala Hospital, Department of Cardiology, Zwolle (Netherlands); Isala Hospital, Department of Nuclear Medicine, Zwolle (Netherlands); Knollema, Siert; Jager, Pieter L. [Isala Hospital, Department of Nuclear Medicine, Zwolle (Netherlands)

    2016-02-15

    Single photon emission computed tomography (SPECT) myocardial perfusion imaging has proven to have prognostic importance in patients with suspected stable coronary artery disease (CAD). The recently introduced ultrafast cadmium zinc telluride (CZT)-based gamma cameras have been associated with less equivocal findings and more normal interpretations, allowing stress-only imaging to be performed more often. However, it is yet unclear whether normal stress-only CZT SPECT has comparable prognostic value as normally interpreted stress-only conventional SPECT. The study population consisted of 1,650 consecutive patients without known CAD with normal stress-only myocardial perfusion results with either conventional (n = 362) or CZT SPECT (n = 1,288). The incidence of major adverse cardiac events (MACE, all-cause death, non-fatal myocardial infarction and/or coronary revascularization) was compared between the conventional SPECT and CZT SPECT groups. Multivariable analyses using the Cox model were used to adjust for differences in baseline variables. Patients scanned with CZT were less often male (33 vs 39 %), had less often hypercholesterolaemia (41 vs 50 %) and had more often a family history of CAD (57 vs 49 %). At a median follow-up time of 37 months (interquartile range 28-45 months) MACE occurred in 68 patients. The incidence of MACE was 1.5 %/year in the CZT group, compared to 2.0 %/year in the conventional group (p = 0.08). After multivariate analyses, there was a trend to a lower incidence of MACE in the CZT SPECT group (hazard ratio 0.61, 95 % confidence interval 0.35-1.04, p = 0.07). The prognostic value of normal stress-only CZT SPECT is at least comparable and may be even better than that of normal conventional stress SPECT. (orig.)

  16. Normalization of flow-mediated dilation to shear stress area under the curve eliminates the impact of variable hyperemic stimulus

    Directory of Open Access Journals (Sweden)

    Mickleborough Timothy D

    2008-09-01

    Full Text Available Abstract Background Normalization of brachial artery flow-mediated dilation (FMD to individual shear stress area under the curve (peak FMD:SSAUC ratio has recently been proposed as an approach to control for the large inter-subject variability in reactive hyperemia-induced shear stress; however, the adoption of this approach among researchers has been slow. The present study was designed to further examine the efficacy of FMD normalization to shear stress in reducing measurement variability. Methods Five different magnitudes of reactive hyperemia-induced shear stress were applied to 20 healthy, physically active young adults (25.3 ± 0. 6 yrs; 10 men, 10 women by manipulating forearm cuff occlusion duration: 1, 2, 3, 4, and 5 min, in a randomized order. A venous blood draw was performed for determination of baseline whole blood viscosity and hematocrit. The magnitude of occlusion-induced forearm ischemia was quantified by dual-wavelength near-infrared spectrometry (NIRS. Brachial artery diameters and velocities were obtained via high-resolution ultrasound. The SSAUC was individually calculated for the duration of time-to-peak dilation. Results One-way repeated measures ANOVA demonstrated distinct magnitudes of occlusion-induced ischemia (volume and peak, hyperemic shear stress, and peak FMD responses (all p AUC (p = 0.785. Conclusion Our data confirm that normalization of FMD to SSAUC eliminates the influences of variable shear stress and solidifies the utility of FMD:SSAUC ratio as an index of endothelial function.

  17. Adenylate kinase I does not affect cellular growth characteristics under normal and metabolic stress conditions.

    Science.gov (United States)

    de Bruin, Wieke; Oerlemans, Frank; Wieringa, Bé

    2004-07-01

    Adenylate kinase (AK)-catalyzed phosphotransfer is essential in the maintenance of cellular energetic economy in cells of fully differentiated tissues with highly variable energy demand, such as muscle and brain. To investigate if AK isoenzymes have a comparable function in the energy-demand management of proliferating cells, AK1 and AK1beta were expressed in mouse neuroblastoma N2a cells and in human colon carcinoma SW480 cells. Glucose deprivation, galactose feeding, and metabolic inhibitor tests revealed a differential energy dependency for these two cell lines. N2a cells showed a faster proliferation rate and strongest coupling to mitochondrial activity, SW480 proliferation was more dependent on glycolysis. Despite these differences, ectopic expression of AK1 or AK1beta did not affect their growth characteristics under normal conditions. Also, no differential effects were seen under metabolic stress upon treatment with mitochondrial and glycolytic inhibitors in in vitro culture or in solid tumors grown in vivo. Although many intimate connections have been revealed between cell death and metabolism, our results suggest that AK1- or AK1beta-mediated high-energy phosphoryl transfer is not a modulating factor in the survival of tumor cells during episodes of metabolic crisis.

  18. Crack onset assessment near the sharp material inclusion tip by means of modified maximum tangential stress criterion

    Czech Academy of Sciences Publication Activity Database

    Krepl, Ondřej; Klusák, Jan

    2017-01-01

    Roč. 11, č. 42 (2017), s. 66-73 ISSN 1971-8993 R&D Projects: GA MŠk(CZ) LQ1601; GA ČR(CZ) GA16-18702S Institutional support: RVO:68081723 Keywords : Generalized fracture mechanics * Sharp material inclusion * Singular and non-singular stress terms Subject RIV: JL - Materials Fatigue, Friction Mechanics OBOR OECD: Audio engineering, reliability analysis

  19. A control systems approach to quantify wall shear stress normalization by flow-mediated dilation in the brachial artery.

    Directory of Open Access Journals (Sweden)

    Frank C G van Bussel

    Full Text Available Flow-mediated dilation is aimed at normalization of local wall shear stress under varying blood flow conditions. Blood flow velocity and vessel diameter are continuous and opposing influences that modulate wall shear stress. We derived an index FMDv to quantify wall shear stress normalization performance by flow-mediated dilation in the brachial artery. In 22 fasting presumed healthy men, we first assessed intra- and inter-session reproducibilities of two indices pFMDv and mFMDv, which consider the relative peak and relative mean hyperemic change in flow velocity, respectively. Second, utilizing oral glucose loading, we evaluated the tracking performance of both FMDv indices, in comparison with existing indices [i.e., the relative peak diameter increase (%FMD, the peak to baseline diameter ratio (Dpeak/Dbase, and the relative peak diameter increase normalized to the full area under the curve of blood flow velocity with hyperemia (FMD/shearAUC or with area integrated to peak hyperemia (FMD/shearAUC_peak]. Inter-session and intra-session reproducibilities for pFMDv, mFMDv and %FMD were comparable (intra-class correlation coefficients within 0.521-0.677 range. Both pFMDv and mFMDv showed more clearly a reduction after glucose loading (reduction of ~45%, p≤0.001 than the other indices (% given are relative reductions: %FMD (~11%, p≥0.074; Dpeak/Dbase (~11%, p≥0.074; FMD/shearAUC_peak (~20%, p≥0.016 and FMD/shearAUC (~38%, p≤0.038. Further analysis indicated that wall shear stress normalization under normal (fasting conditions is already far from ideal (FMDv << 1, which (therefore does not materially change with glucose loading. Our approach might be useful in intervention studies to detect intrinsic changes in shear stress normalization performance in conduit arteries.

  20. Normal personality traits, rumination and stress generation among early adolescent girls

    Science.gov (United States)

    Stroud, Catherine B.; Sosoo, Effua E.; Wilson, Sylia

    2017-01-01

    This study examined associations between personality and stress generation. Expanding upon prior work, we examined (a) the role of Positive Emotionality (PE), Negative Emotionality (NE), and Constraint (CON), and their lower-order facets, as predictors of acute and chronic interpersonal stress generation; (b) whether personality moderated effects of rumination on stress generation; and (c) whether personality increased exposure to independent (uncontrollable) stress. These questions were examined in a one-year study of 126 adolescent girls (M age = 12.39 years) using contextual stress interviews. NE predicted increases in acute and chronic interpersonal stress generation, but not independent stress. NE, CON and affiliative PE each moderated the effect of rumination on chronic interpersonal stress generation. These effects were driven by particular lower-order traits. PMID:28845067

  1. Artichoke compound cynarin differentially affects the survival, growth and stress response of normal, immortalized and cancerous human cells

    DEFF Research Database (Denmark)

    Gezer, Ceren; Yücecan, Sevinç; Rattan, Suresh Inder Singh

    2015-01-01

    of CYN on the proliferative potential, survival, morphology, and stress response (SR) markers haemoxygenase-1 (HO-1) and heat shock protein-70 (HSP70) in normal human skin fibroblasts (FSF-1), telomerase-immortalized mesenchymal stem cells (hTERT-MSC) and cervical cancer cells, HeLa. Effects of CYN...

  2. Normal personality traits, rumination and stress generation among early adolescent girls

    OpenAIRE

    Stroud, Catherine B.; Sosoo, Effua E.; Wilson, Sylia

    2015-01-01

    This study examined associations between personality and stress generation. Expanding upon prior work, we examined (a) the role of Positive Emotionality (PE), Negative Emotionality (NE), and Constraint (CON), and their lower-order facets, as predictors of acute and chronic interpersonal stress generation; (b) whether personality moderated effects of rumination on stress generation; and (c) whether personality increased exposure to independent (uncontrollable) stress. These questions were exam...

  3. Investigation of stress distribution in normal and oblique partial penetration. Welded nozzles by 3-D photoelastic stress freezing method

    International Nuclear Information System (INIS)

    Miyamoto, H.; Kubo, M.; Katori, T.

    1981-01-01

    Experimental investigation by 3-D photoelasticity has been carried out to measure the stress distribution of partial penetration welded nozzles attached to the bottom head of a pressure vessel. A 3-D photoelastic stress freezing method was chosen as the most effective means of observation of the stress distribution in the vicinity of the nozzle/wall weld. The experimental model was a 1:20 scale spherical bottom head. Both an axisymmetric nozzle and an asymmetric nozzle were investigated. Epoxy resin, which is a thermosetting plastic, was used as the model material. The oblique effect was examined by comparing the stress distribution of the asymmetric nozzle with that of the axisymmetric nozzle. Furthermore, the experimental results were compared with the analytical results using 3-D finite element method (FEM). The stress distributions obtained from the frozen fringe pattern of the 3-D photoelastic model were in good agreement with those by 3-D FEM. (orig.)

  4. Stability of faults with heterogeneous friction properties and effective normal stress

    Science.gov (United States)

    Luo, Yingdi; Ampuero, Jean-Paul

    2018-05-01

    Abundant geological, seismological and experimental evidence of the heterogeneous structure of natural faults motivates the theoretical and computational study of the mechanical behavior of heterogeneous frictional fault interfaces. Fault zones are composed of a mixture of materials with contrasting strength, which may affect the spatial variability of seismic coupling, the location of high-frequency radiation and the diversity of slip behavior observed in natural faults. To develop a quantitative understanding of the effect of strength heterogeneity on the mechanical behavior of faults, here we investigate a fault model with spatially variable frictional properties and pore pressure. Conceptually, this model may correspond to two rough surfaces in contact along discrete asperities, the space in between being filled by compressed gouge. The asperities have different permeability than the gouge matrix and may be hydraulically sealed, resulting in different pore pressure. We consider faults governed by rate-and-state friction, with mixtures of velocity-weakening and velocity-strengthening materials and contrasts of effective normal stress. We systematically study the diversity of slip behaviors generated by this model through multi-cycle simulations and linear stability analysis. The fault can be either stable without spontaneous slip transients, or unstable with spontaneous rupture. When the fault is unstable, slip can rupture either part or the entire fault. In some cases the fault alternates between these behaviors throughout multiple cycles. We determine how the fault behavior is controlled by the proportion of velocity-weakening and velocity-strengthening materials, their relative strength and other frictional properties. We also develop, through heuristic approximations, closed-form equations to predict the stability of slip on heterogeneous faults. Our study shows that a fault model with heterogeneous materials and pore pressure contrasts is a viable framework

  5. Speech perception in older listeners with normal hearing:conditions of time alteration, selective word stress, and length of sentences.

    Science.gov (United States)

    Cho, Soojin; Yu, Jyaehyoung; Chun, Hyungi; Seo, Hyekyung; Han, Woojae

    2014-04-01

    Deficits of the aging auditory system negatively affect older listeners in terms of speech communication, resulting in limitations to their social lives. To improve their perceptual skills, the goal of this study was to investigate the effects of time alteration, selective word stress, and varying sentence lengths on the speech perception of older listeners. Seventeen older people with normal hearing were tested for seven conditions of different time-altered sentences (i.e., ±60%, ±40%, ±20%, 0%), two conditions of selective word stress (i.e., no-stress and stress), and three different lengths of sentences (i.e., short, medium, and long) at the most comfortable level for individuals in quiet circumstances. As time compression increased, sentence perception scores decreased statistically. Compared to a natural (or no stress) condition, the selectively stressed words significantly improved the perceptual scores of these older listeners. Long sentences yielded the worst scores under all time-altered conditions. Interestingly, there was a noticeable positive effect for the selective word stress at the 20% time compression. This pattern of results suggests that a combination of time compression and selective word stress is more effective for understanding speech in older listeners than using the time-expanded condition only.

  6. In vitro culture of oocytes and granulosa cells collected from normal, obese, emaciated and metabolically stressed ewes.

    Science.gov (United States)

    Tripathi, S K; Farman, M; Nandi, S; Mondal, S; Gupta, Psp; Kumar, V Girish

    2016-07-01

    The present study was undertaken to investigate the oocyte morphology, its fertilizing capacity and granulosa cell functions in ewes (obese, normal, metabolic stressed and emaciated). Ewes (Ovis aries) of approximately 3 years of age (Bellary breed) from a local village were screened, chosen and categorized into a) normal b) obese but not metabolically stressed, c) Emaciated but not metabolically stressed d) Metabolically stressed based on body condition scoring and blood markers. Oocytes and granulosa cells were collected from ovaries of the ewes of all categories after slaughter and were classified into good (oocytes with more than three layers of cumulus cells and homogenous ooplasm), fair (oocytes one or two layers of cumulus cells and homogenous ooplasm) and poor (denuded oocytes or with dark ooplasm). The good and fair quality oocytes were in vitro matured and cultured with fresh semen present and the fertilization, cleavage and blastocyst development were observed. The granulosa cells were cultured for evaluation of metabolic activity by use of the MTT assay, and cell viability, cell number as well as estrogen and progesterone production were assessed. It was observed that the good and fair quality oocytes had greater metabolic activity when collected from normal and obese ewes compared with those from emaciated and metabolically stressed ewes. No significant difference was observed in oocyte quality and maturation amongst the oocytes collected from normal and obese ewes. The cleavage and blastocyst production rates were different for the various body condition classifications and when ranked were: normal>obese>metabolically stressed>emaciated. Lesser metabolic activity was observed in granulosa cells obtained from ovaries of emaciated ewes. However, no changes were observed in viability and cell number of granulosa cells obtained from ewes with the different body condition categories. Estrogen and progesterone production from cultured granulosa cells were

  7. Comparison in stress of caring mothers of children with developmental, external and internal disorders and normal children

    Directory of Open Access Journals (Sweden)

    Narges Zamani

    2017-06-01

    Full Text Available However, having a baby brings positive emotions such as happiness, sense of maturity and proud, parenting's issue could cause high level of stress and child's characteristics was a detrimental factor which can effect on parent's stress, so the aim of this research was comparison of stress of caring in mothers of children with developmental, external, and internal disorders and normal children. The study population included all mothers of children with developmental, emotional, and disruptive behavior disorders, and mothers with normal children in Hamadan (a city in Iran. 240 mothers (4 groups include 60 mothers were chosen based on simple random sampling. Family inventory of life events and changes Mc Cubbin, Patterson & Wilson was used for assessing participants. The results showed that maternal stress in mothers with children who have diagnosis of disruptive behavior disorders were significantly more than of mothers of children with developmental disorders, emotional and mothers of normal children. The present study showed that disruptive behavior disorders in children have a greater impact on their mothers. So, we suggest approved psychological interventions for helping mothers of children with psychological problems, particularly children with external disorders.

  8. Escitalopram and NHT normalized stress-induced anhedonia and molecular neuroadaptations in a mouse model of depression.

    Directory of Open Access Journals (Sweden)

    Or Burstein

    Full Text Available Anhedonia is defined as a diminished ability to obtain pleasure from otherwise positive stimuli. Anxiety and mood disorders have been previously associated with dysregulation of the reward system, with anhedonia as a core element of major depressive disorder (MDD. The aim of the present study was to investigate whether stress-induced anhedonia could be prevented by treatments with escitalopram or novel herbal treatment (NHT in an animal model of depression. Unpredictable chronic mild stress (UCMS was administered for 4 weeks on ICR outbred mice. Following stress exposure, animals were randomly assigned to pharmacological treatment groups (i.e., saline, escitalopram or NHT. Treatments were delivered for 3 weeks. Hedonic tone was examined via ethanol and sucrose preferences. Biological indices pertinent to MDD and anhedonia were assessed: namely, hippocampal brain-derived neurotrophic factor (BDNF and striatal dopamine receptor D2 (Drd2 mRNA expression levels. The results indicate that the UCMS-induced reductions in ethanol or sucrose preferences were normalized by escitalopram or NHT. This implies a resemblance between sucrose and ethanol in their hedonic-eliciting property. On a neurobiological aspect, UCMS-induced reduction in hippocampal BDNF levels was normalized by escitalopram or NHT, while UCMS-induced reduction in striatal Drd2 mRNA levels was normalized solely by NHT. The results accentuate the association of stress and anhedonia, and pinpoint a distinct effect for NHT on striatal Drd2 expression.

  9. Analysis of the original causes of placental oxidative stress in normal pregnancy and pre-eclampsia: a hypothesis.

    Science.gov (United States)

    Yang, Xiang; Guo, Lili; Li, Huaifang; Chen, Xinliang; Tong, Xiaowen

    2012-07-01

    Pre-eclampsia (PE) and eclampsia remain enigmatic despite intensive research. Growing evidence suggests that placental oxidative stress (OS) is involved in the etiopathogenesis of pre-eclampsia. Reduced perfusion as a result of abnormal placentation was proposed to be responsible for placental OS in PE. However, placental OS was also observed in normal pregnancy. The exact differences and correlation of placental OS in PE and normal pregnancy remain elusive. In this review, we attempted to link both normal pregnancy and PE on the causes of placental OS and proposed a hypothesis that placental OS in normal pregnancy, plus the exploration of other placental and/or maternal factors, could provide a novel explanation of that in PE. We concluded that pregnancy, placental abnormality and preexisting maternal constitutional conditions are three principle factors that could contribute to placental OS in PE. The specific causes in each clinical case could be heterogeneous, which requires individual analysis.

  10. Studies on Impingement Effects of Low Density Jets on Surfaces — Determination of Shear Stress and Normal Pressure

    Science.gov (United States)

    Sathian, Sarith. P.; Kurian, Job

    2005-05-01

    This paper presents the results of the Laser Reflection Method (LRM) for the determination of shear stress due to impingement of low-density free jets on flat plate. For thin oil film moving under the action of aerodynamic boundary layer the shear stress at the air-oil interface is equal to the shear stress between the surface and air. A direct and dynamic measurement of the oil film slope is measured using a position sensing detector (PSD). The thinning rate of oil film is directly measured which is the major advantage of the LRM over LISF method. From the oil film slope history, direct calculation of the shear stress is done using a three-point formula. For the full range of experiment conditions Knudsen numbers varied till the continuum limit of the transition regime. The shear stress values for low-density flows in the transition regime are thus obtained using LRM and the measured values of shear show fair agreement with those obtained by other methods. Results of the normal pressure measurements on a flat plate in low-density jets by using thermistors as pressure sensors are also presented in the paper. The normal pressure profiles obtained show the characteristic features of Newtonian impact theory for hypersonic flows.

  11. Normalization of flow-mediated dilation to shear stress area under the curve eliminates the impact of variable hyperemic stimulus.

    Science.gov (United States)

    Padilla, Jaume; Johnson, Blair D; Newcomer, Sean C; Wilhite, Daniel P; Mickleborough, Timothy D; Fly, Alyce D; Mather, Kieren J; Wallace, Janet P

    2008-09-04

    Normalization of brachial artery flow-mediated dilation (FMD) to individual shear stress area under the curve (peak FMD:SSAUC ratio) has recently been proposed as an approach to control for the large inter-subject variability in reactive hyperemia-induced shear stress; however, the adoption of this approach among researchers has been slow. The present study was designed to further examine the efficacy of FMD normalization to shear stress in reducing measurement variability. Five different magnitudes of reactive hyperemia-induced shear stress were applied to 20 healthy, physically active young adults (25.3 +/- 0. 6 yrs; 10 men, 10 women) by manipulating forearm cuff occlusion duration: 1, 2, 3, 4, and 5 min, in a randomized order. A venous blood draw was performed for determination of baseline whole blood viscosity and hematocrit. The magnitude of occlusion-induced forearm ischemia was quantified by dual-wavelength near-infrared spectrometry (NIRS). Brachial artery diameters and velocities were obtained via high-resolution ultrasound. The SSAUC was individually calculated for the duration of time-to-peak dilation. One-way repeated measures ANOVA demonstrated distinct magnitudes of occlusion-induced ischemia (volume and peak), hyperemic shear stress, and peak FMD responses (all p index of endothelial function.

  12. Stresses in a simplified two dimensional model of a normal foot : a preliminary analysis

    NARCIS (Netherlands)

    Patil, K.M.; Braak, L.H.; Huson, A.

    1993-01-01

    The loss of motor functions of the foot muscles in leprosy or diabetes changes the pattern of internal stresses in the foot skeleton. This may provoke local foci of relatively high stresses. In those cases where osteoporosis and cystic degeneration has weakened the mechanical strength of the bones,

  13. Electroconvulsive stimulations normalizes stress-induced changes in the glucocorticoid receptor and behaviour

    DEFF Research Database (Denmark)

    Hageman, Ida; Nielsen, Marianne; Wörtwein, Gitta

    2009-01-01

    Animal models of chronic stress, such as 21 days of 6h/daily restraint stress cause changes in neuronal morphology in the hippocampus and alter behaviour. These changes are partly mediated by the glucocorticoids. The objective of this study was threefold: (1) to study how this particular chronic ...

  14. Interaction between a normal shock wave and a turbulent boundary layer at high transonic speeds. II - Wall shear stress

    Science.gov (United States)

    Liou, M. S.; Adamson, T. C., Jr.

    1980-01-01

    Asymptotic methods are used to calculate the shear stress at the wall for the interaction between a normal shock wave and a turbulent boundary layer on a flat plate. A mixing length model is used for the eddy viscosity. The shock wave is taken to be strong enough that the sonic line is deep in the boundary layer and the upstream influence is thus very small. It is shown that unlike the result found for laminar flow an asymptotic criterion for separation is not found; however, conditions for incipient separation are computed numerically using the derived solution for the shear stress at the wall. Results are compared with available experimental measurements.

  15. Partial LVAD restores ventricular outputs and normalizes LV but not RV stress distributions in the acutely failing heart in silico

    OpenAIRE

    Sack, Kevin L.; Baillargeon, Brian; Acevedo-Bolton, Gabriel; Genet, Martin; Rebelo, Nuno; Kuhl, Ellen; Klein, Liviu; Weiselthaler, Georg M.; Burkhoff, Daniel; Franz, Thomas; Guccione, Julius M.

    2016-01-01

    Purpose: Heart failure is a worldwide epidemic that is unlikely to change as the population ages and life expectancy increases. We sought to detail significant recent improvements to the Dassault Systèmes Living Heart Model (LHM) and use the LHM to compute left ventricular (LV) and right ventricular (RV) myofiber stress distributions under the following 4 conditions: (1) normal cardiac function; (2) acute left heart failure (ALHF); (3) ALHF treated using an LV assist device (LVAD) flow rate o...

  16. Interpretation of metabolic memory phenomenon using a physiological systems model: What drives oxidative stress following glucose normalization?

    Science.gov (United States)

    Voronova, Veronika; Zhudenkov, Kirill; Helmlinger, Gabriel; Peskov, Kirill

    2017-01-01

    Hyperglycemia is generally associated with oxidative stress, which plays a key role in diabetes-related complications. A complex, quantitative relationship has been established between glucose levels and oxidative stress, both in vitro and in vivo. For example, oxidative stress is known to persist after glucose normalization, a phenomenon described as metabolic memory. Also, uncontrolled glucose levels appear to be more detrimental to patients with diabetes (non-constant glucose levels) vs. patients with high, constant glucose levels. The objective of the current study was to delineate the mechanisms underlying such behaviors, using a mechanistic physiological systems modeling approach that captures and integrates essential underlying pathophysiological processes. The proposed model was based on a system of ordinary differential equations. It describes the interplay between reactive oxygen species production potential (ROS), ROS-induced cell alterations, and subsequent adaptation mechanisms. Model parameters were calibrated using different sources of experimental information, including ROS production in cell cultures exposed to various concentration profiles of constant and oscillating glucose levels. The model adequately reproduced the ROS excess generation after glucose normalization. Such behavior appeared to be driven by positive feedback regulations between ROS and ROS-induced cell alterations. The further oxidative stress-related detrimental effect as induced by unstable glucose levels can be explained by inability of cells to adapt to dynamic environment. Cell adaptation to instable high glucose declines during glucose normalization phases, and further glucose increase promotes similar or higher oxidative stress. In contrast, gradual ROS production potential decrease, driven by adaptation, is observed in cells exposed to constant high glucose.

  17. An increased rectal maximum tolerable volume and long anal canal are associated with poor short-term response to biofeedback therapy for patients with anismus with decreased bowel frequency and normal colonic transit time.

    Science.gov (United States)

    Rhee, P L; Choi, M S; Kim, Y H; Son, H J; Kim, J J; Koh, K C; Paik, S W; Rhee, J C; Choi, K W

    2000-10-01

    Biofeedback is an effective therapy for a majority of patients with anismus. However, a significant proportion of patients still failed to respond to biofeedback, and little has been known about the factors that predict response to biofeedback. We evaluated the factors associated with poor response to biofeedback. Biofeedback therapy was offered to 45 patients with anismus with decreased bowel frequency (less than three times per week) and normal colonic transit time. Any differences in demographics, symptoms, and parameters of anorectal physiologic tests were sought between responders (in whom bowel frequency increased up to three times or more per week after biofeedback) and nonresponders (in whom bowel frequency remained less than three times per week). Thirty-one patients (68.9 percent) responded to biofeedback and 14 patients (31.1 percent) did not. Anal canal length was longer in nonresponders than in responders (4.53 +/- 0.5 vs. 4.08 +/- 0.56 cm; P = 0.02), and rectal maximum tolerable volume was larger in nonresponders than in responders. (361 +/- 87 vs. 302 +/- 69 ml; P = 0.02). Anal canal length and rectal maximum tolerable volume showed significant differences between responders and nonresponders on multivariate analysis (P = 0.027 and P = 0.034, respectively). This study showed that a long anal canal and increased rectal maximum tolerable volume are associated with poor short-term response to biofeedback for patients with anismus with decreased bowel frequency and normal colonic transit time.

  18. Effect Of Extensive Use Of Garlic In Feed On Normal And Irradiated Stressed Male Rats

    International Nuclear Information System (INIS)

    KASSAB, F.M.A.; ABDEL-KHALEK, L.G.; KAMAL, A.M.

    2009-01-01

    Fifty mature male albino rats were used in the present study to evaluate the effect of using crude garlic for one month on general heath condition and to compare between garlic intakes pre and post-irradiated stressed rats.Fresh minced cloves (8-10) of garlic were added to the rat diet twice per day for 30 days in garlic group and for 7 and 15 days prior to and after 4 Gy irradiation in pre and post-irradiated garlic groups, respectively. The results denoted that the extensive use of garlic in food improved the general condition in non-stressed rats while in irradiated stressed rats, the immediate intake of garlic after radiation was more efficient in ameliorating the undesirable radiation effects, where some biochemical and hematological parameters were examined in pre and post-garlic intake such as Hb, RBCs, platelets, T 3 , testosterone and insulin.

  19. Vitamin K3 increased BMD at 1 and 2 months post-surgery and the maximum stress of the middle femur in the rat.

    Science.gov (United States)

    Hong, You-jia; Liu, Sheng; Jiang, Ning-yi; Jiang, Sen; Liang, Jiu-gen

    2015-02-01

    The therapeutic effects of vitamin K3 (VK3) on osteoporosis are still unknown. In this study, we hypothesized that VK3 possesses therapeutic effects on osteoporosis; to verify this hypothesis, the ovariectomized rat was used as an osteoporosis model. Fifty-six Sprague-Dawley female rats aged 8 to 9 months were randomly assigned to 4 groups: sham surgery, ovariectomy with saline, ovariectomy with low-dose VK3, and ovariectomy with high-dose VK3. Intramuscular injection of VK3 was performed every other day beginning 1 month postoperatively. The therapeutic effects of VK3 on osteoporosis were evaluated by measurement of bone mineral density (BMD), bone biochemical markers, biomechanical properties, and bone morphometric parameters. The overall average BMD in VK3-treated groups increased to a level between those of the ovariectomy group and the sham surgery group. The procollagen I N-terminal peptide level peaked at 2 months after surgery in all groups except in the group that had undergone ovariectomy with low-dose VK3. The tartrate-resistant acid phosphatase 5b level increased more slowly at 4 months after surgery than at 2 months after surgery in the VK3-treated groups. The ovariectomy with high-dose VK3 group had the highest maximum stress of the middle femur of all groups. With VK3 treatment, the trabecular bone area percentage increased. All morphometric indicators for the middle tibia in the VK3-treated groups reached the levels found in the sham surgery group. In summary, VK3 therapy increased BMD at 1 and 2 months postsurgery and the maximum stress of the middle femur. In addition, VK3 therapy slowed the increase in bone turnover in ovariectomized rats. Furthermore, VK3 can improve morphometric indicators for the middle tibia. Our preliminary study indicates that VK3 has a potential therapeutic effect on osteoporosis and is worthy of further investigation. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Prognostic significance of normal quantitative Tl-201 stress scintigraphy in relation to pretest likelihood of coronary artery disease

    International Nuclear Information System (INIS)

    Russo, D.J.; Russo, D.; Clements, J.; Wackers, F.

    1984-01-01

    A previous study reported an excellent prognosis and low cardiac event rate in patients(pts) with chest pain and normal quantitative T1-201 scintigraphy(SC). Such result would not be unexpected if the population under study had a predominance of pts with low pre-T1-201 likelihood(L) of significant coronary artery disease (CAD). Hence, the authors undertook telephone follow-up in pts with chest pain syndrome and normal quantitative T1-201 exercise SC, and related outcome to pretest L of CAD. Pretest L was determined by serial L analysis on the basis of: symptoms, age, sex, and exercise ECG. All pts had T1-201 SC immediately post exercise and 2 hrs later. After interpolative background correction, circumferential count and washout profiles were generated. All pts had unequivocally normal studies. Of a total of 96 pts studied in 1981-82, 20 pts were lost to follow-up. Of the remaining 76 pts, 45 were males and 31 females. The pretest L of CAD had an inverted Gaussian distribution: thirty-four pts(47%) had 66% L of CAD. Mean follow-up was 22+- 3 months. No deaths occurred. Two pts(3%) (with pretest L of 54% and 94%) had myocardial infarctions, 8 and 22 months respectively after T1-201 stress SC. One pt underwent percutaneous transluminal coronary angioplasty (PTCA) 16 months after T1-201 stress SC. These findings confirm excellent prognostic significance of normal quantitative T1-201 stress scintigraphy

  1. Transducer for measuring normal and friction stress in contact zone during rolling

    DEFF Research Database (Denmark)

    Henningsen, Poul; Wanheim, Tarras; Arentoft, Mogens

    2004-01-01

    , generating frictional stresses contrary to the direction of rolling. In a narrow area in the deformation zone, the velocity of the deformed material is equal to the velocity of the rolls. This area or line is named “neutral line”[2]. The position of the neutral line depends on friction, reduction ratio...

  2. Evaluation of some sorghum genotypes under normal and moisture-stress conditions

    International Nuclear Information System (INIS)

    Abu Assar, A. H.; Salih, M.; Wagner, C.; Friedt, W.; Abdelmula, A. A.; Ordon, F.; Steffens, D.

    2008-01-01

    This study was undertaken to identify the morphological and physiological attributes related to drought tolerance in sorghum (sorghum bicolor (L) Moench). Eight genotypes were tested in a pot experiment carried out at Giessen, Germany. Drought conditions were imposed by withholding watering of the plants when filed water-holding capacity was at 40% and 70%. The tested genotypes differed significantly in most of the measured traits. Grain yield under drought stress ranged from 28 to 61 g/ plant, and relative yield ranged 30% to 56% with an average of 47%. Based on yield/plant, the genotypes Wad Ahmed (61g). SAR 41 (55 g) and ICSR 91030 (54 g) were the best under drought stress conditions, and based on relative yield, the best genotypes were SAR 41 (56%), Wad Ahmed (55%), and Red Mugud (53%). The mean potassium content was 18 mg/g, with a range of 14 mg/g (Red Mugud) to 22 mg/g (Arfa Gadamak). Significant difference were obtained for protein percentage of the dry matter under conditions of drought stress. The values ranged form 14.1% (Red Mugud) to 16.7% (Tabat) with a mean of 15.3%. Grain yield under drought stress was positively correlated with relative yield (r= 0.89), total biomass (r= 0.56), number of seeds per panicle (r= 0.66) and harvest index (r= 0.81), but negatively correlated with 1000-grain (r= 0.37). (Author)

  3. Seismic sensitivity of normal-mode coupling to Lorentz stresses in the Sun

    Science.gov (United States)

    Hanasoge, Shravan M.

    2017-09-01

    Understanding the governing mechanism of solar magnetism remains an outstanding challenge in astrophysics. Seismology is the most compelling technique to infer the internal properties of the Sun and stars. Waves in the Sun, nominally acoustic, are sensitive to the emergence and cyclical strengthening of magnetic field, evidenced by measured changes in resonant oscillation frequencies that are correlated with the solar cycle. The inference of internal Lorentz stresses from these measurements has the potential to significantly advance our appreciation of the dynamo. Indeed, seismological inverse theory for the Sun is well understood for perturbations in composition, thermal structure and flows but, is not fully developed for magnetism, owing to the complexity of the ideal magnetohydrodynamic (MHD) equation. Invoking first-Born perturbation theory to characterize departures from spherically symmetric hydrostatic models of the Sun and applying the notation of generalized spherical harmonics, we calculate sensitivity functions of seismic measurements to the general time-varying Lorentz stress tensor. We find that eigenstates of isotropic (I.e. acoustic only) background models are dominantly sensitive to isotropic deviations in the stress tensor and much more weakly than anisotropic stresses (and therefore challenging to infer). The apple cannot fall far from the tree.

  4. Normal stress differences from Oldroyd 8-constant framework: Exact analytical solution for large-amplitude oscillatory shear flow

    Science.gov (United States)

    Saengow, C.; Giacomin, A. J.

    2017-12-01

    The Oldroyd 8-constant framework for continuum constitutive theory contains a rich diversity of popular special cases for polymeric liquids. In this paper, we use part of our exact solution for shear stress to arrive at unique exact analytical solutions for the normal stress difference responses to large-amplitude oscillatory shear (LAOS) flow. The nonlinearity of the polymeric liquids, triggered by LAOS, causes these responses at even multiples of the test frequency. We call responses at a frequency higher than twice the test frequency higher harmonics. We find the new exact analytical solutions to be compact and intrinsically beautiful. These solutions reduce to those of our previous work on the special case of the corotational Maxwell fluid. Our solutions also agree with our new truncated Goddard integral expansion for the special case of the corotational Jeffreys fluid. The limiting behaviors of these exact solutions also yield new explicit expressions. Finally, we use our exact solutions to see how η∞ affects the normal stress differences in LAOS.

  5. Elastoplastical Analysis of the Interface between Clay and Concrete Incorporating the Effect of the Normal Stress History

    Directory of Open Access Journals (Sweden)

    Zhao Cheng

    2013-01-01

    Full Text Available The behaviour of the soil-structure interface is crucial to the design of a pile foundation. Radial unloading occurs during the process of hole boring and concrete curing, which will affect the load transfer rule of the pile-soil interface. Through large shear tests on the interface between clay and concrete, it can be concluded that the normal stress history significantly influences the shear behaviour of the interface. The numerical simulation of the bored shaft-soil interaction problem requires proper modelling of the interface. By taking the energy accumulated on the interface as a hardening parameter and viewing the shearing process of the interface as the process of the energy dissipated to do work, considering the influence of the normal stress history on the shearing rigidity, a mechanical model of the interface between clay and concrete is proposed. The methods to define the model parameters are also introduced. The model is based on a legible mathematical theory, and all its parameters have definite physical meaning. The model was validated using data from a direct shear test; the validation results indicated that the model can reproduce and predict the mechanical behaviour of the interface between clay and concrete under an arbitrary stress history.

  6. Oxidative stress and acrosomal morphology: A cause of infertility in patients with normal semen parameters

    Directory of Open Access Journals (Sweden)

    Moustafa A. El-Taieb

    2015-06-01

    Conclusion: Percentages of MDA values and acrosomal anomalies were higher in infertile patients than normal subjects. The positive correlation between acrosomal anomalies and MDA values means association between OS and acrosomal anomalies which may indicate negative effects of OS on the acrosomal structure.

  7. Physiological antioxidant system and oxidative stress in stomach cancer patients with normal renal and hepatic function

    Directory of Open Access Journals (Sweden)

    E Prabhakar Reddy

    2010-04-01

    Full Text Available Role of free radicals has been proposed in the pathogenesis of many diseases. Gastric cancer is a common disease worldwide, and leading cause of cancer death in India. Severe oxidative stress produces reactive oxygen species (ROS and induces uncontrolled lipid peroxidation. Albumin, uric acid (UA and Bilirubin are important physiological antioxidants. We aimed to evaluate and assess the role of oxidative stress (OS and physiological antioxidant system in stomach cancer patients. Lipid peroxidation measured as plasma Thio Barbituric Acid Reactive substances (TBARS, was found to be elevated significantly (p=0.001 in stomach cancer compared to controls along with a decrease in plasma physiological antioxidant system. The documented results were due to increased lipid peroxidation and involvement of physiological antioxidants in scavenging free radicals but not because of impaired hepatic and renal functions.

  8. Evaluation of visual stress symptoms in age-matched dyslexic, Meares-Irlen syndrome and normal adults.

    Science.gov (United States)

    Alanazi, Mana A; Alanazi, Saud A; Osuagwu, Uchechukwu L

    2016-01-01

    To examine the prevalence of dyslexia and Meares-Irlen syndrome (MIS) among female students and determine their level of visual stress in comparison with normal subjects. A random sample of 450 female medical students of King Saud University Riyadh (age range, 18-30y) responded to a wide range of questions designed to accomplish the aims of this study. The detailed questionnaire consisted of 54 questions with 12 questions enquiring on ocular history and demography of participants while 42 questions were on visual symptoms. Items were categorized into critical and non-critical questions (CQ and NCQ) and were rated on four point Likert scale. Based on the responses obtained, the subjects were grouped into normal (control), dyslexic with or without MIS (Group 1) and subjects with MIS only (Group 2). Responses were analysed as averages and mean scores were calculated and compared between groups using one way analysis of variance to evaluate total visual stress score (TVSS=NCQ+CQ), critical and non-critical visual stress scores. The relationship between categorical variables such as age, handedness and condition were assessed with Chi-square test. The completion rate was 97.6% and majority of the respondents (92%) were normal readers, 2% dyslexic and 6% had MIS. They were age-matched. More than half of the participants had visited an eye care practitioner in the last 2y. About 13% were recommended eye exercises and one participant experienced pattern glare. Hand preference was not associated with any condition but Group 1 subjects (3/9, 33%) were significantly more likely to be diagnosed of lazy eye than Group 2 (2/27, 7%) and control (27/414, 7%) subjects. The mean±SD of TVSS responses were 63±14 and it was 44±9 for CQ and 19±5 for NCQ. Responses from all three variables were normally distributed but the CQ responses were on the average more positive (82%) in Group 2 and less positive (46%) in Group 1 than control. With NCQ, the responses were equally less positive

  9. Terfenol-D/Pb(Zr,Ti)O{sub 3} disk-ring multiferroic heterostructures coupled through normal stresses

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lei; Chen, Xiang Ming [Zhejiang University, Laboratory of Dielectric Materials, Department of Materials Science and Engineering, Hangzhou (China)

    2010-03-15

    Disk-ring multiferroic heterostructures composed of Terfenol-D and Pb(Zr,Ti)O{sub 3} (PZT) were prepared and characterized, for which the ferromagnetic and ferroelectric phases were coupled through normal stresses instead of the shear stresses that acted in most of the previous multiferroic heterostructures. High low-frequency magnetoelectric coefficients of 0.10-0.75 V cm{sup -1} Oe{sup -1} were attained for the disk-ring heterostructures, which indicated the strong magnetoelectric coupling. Moreover, a symmetrical resonant peak was observed for dE{sub 3}/dH{sub 3} in the frequency range of 1-200 kHz, while another weak peak with asymmetrical shape also existed at a lower frequency for dE{sub 3}/dH{sub 1}, which was due to the combination of two vibration modes. (orig.)

  10. Chronic stress effects on hippocampal structure and synaptic function: relevance for depression and normalization by anti-glucocorticoid treatment

    Directory of Open Access Journals (Sweden)

    Harmen J Krugers

    2010-07-01

    Full Text Available Exposure of an organism to environmental challenges activates two hormonal systems that help the organism to adapt. As part of this adaptational process, brain processes are changed such that appropriate behavioral strategies are selected that allow optimal performance at the short term, while relevant information is stored for the future. Over the past years it has become evident that chronic uncontrollable and unpredictable stress also exerts profound effects on structure and function of limbic neurons, but the impact of chronic stress is not a mere accumulation of repeated episodes of acute stress exposure. Dendritic trees are reduced in some regions but expanded in others, and cells are generally exposed to a higher calcium load upon depolarization. Synaptic strengthening is largely impaired. Neurotransmitter responses are also changed, e.g. responses to serotonin. We here discuss: a the main cellular effects after chronic stress with emphasis on the hippocampus, b how such effects could contribute to the development of psychopathology in genetically vulnerable individuals, and c their normalization by brief treatment with anti-glucocorticoids.

  11. Numerical Analysis of a New Pressure Sensor for Measuring Normal and Tangential Stresses in the Roll Gap

    DEFF Research Database (Denmark)

    Presz, Wojtek P.; Wanheim, Tarras

    2003-01-01

    The paper is in polish. Orig. title: "Analiza numeryczna nowego czujnika do pomiaru nacisków i naprê¿eñ stycznych w procesie walcowania" A new strain gauge sensor for measuring normal and tangential stresses in the contact arc of a rolling process has been designed and constructed. The complicated...... load history of the sensor results in complicated deformation patterns of it, and consequently the calibration procedure of the sensor should cover a wide range of loading cases, and would thus be very difficult and time-consuming to carry out. As an alternative to this, a FEM simulative experiment has...

  12. Scintigraphic assessment of normal values of lower limb perfusion under stress and rest, with possible clinical applications

    International Nuclear Information System (INIS)

    Malkowski, B.; Zajac, A.; Maziarz, Z.; Zaborowski, G.; Ryglewska-Brzozowska, M.; Malara, A.; Tryniszewski, W.

    2005-01-01

    The lack of a range of normal values of perfusion in the lower limbs during stress and at rest narrows the use of this type of diagnostic tool to the estimation of the current state of relative perfusion without indications of the presence or level of perfusion disturbances. Numerous reports on early changes in endothelium reactivity (depending on disease and degree of vessel pathology) encouraged us to assess lower limb perfusion in healthy people. Our goal was to 1) work out a program and method which would enable lower limb perfusion assessment under stress and at rest in patients without signs of lower limb circulation deprivation and 2) establish the normal range of indexes of lower limb perfusion under stress and at rest which would enable their use in the diagnostics of lower limb muscle circulation. 33 male patients aged between 25 to 45 years (mean: 35.30 ± 6.04) without signs of circulatory problems were entered into the study. To exclude circulatory disturbances, Doppler USG, blood pressure, and laboratory tests were performed on every patient at rest 5 min. after the injection of 11.1 MBq/kg 99 mTc MIBI. Whole body as well as thigh and calf scintigrams were made with an ELSCINT SP6HR gamma-camera. The symmetry of the thigh and calf perfusion (WSU, WSP) and the indexes of the thigh (WPLU, WPPU) and calf (WPLP, WSPP) perfusion of both lower limbs were estimated. At rest: WSP: 96.47% ±1.02, WSP: 96.47% ± 1.02, WPLP: 9.77 ± 0.32, WPPP: 9.78 ± 0.31, WPLU: 8.45 ± 0.22, WPPU: 8.48 ± 0.22. Under stress: WSP: 96.69% ± 1.32, WSU: 96.41% ± 1.20, WPLP: 8.78 ± 0.26, WPPP: 8.81 ± 0.25, WPLU: 7.77 ± 0.25, WPPU: 7.82 ± 0.26. Anamnesis, additional studies, and laboratory tests in the group examined did not show any circulatory disturbances. The estimated values in patients without circulatory disturbances are similar and within a narrow range, which allows us to calculate the norms of lower limb perfusion at rest and under stress. The determined normal

  13. Identification of Appropriate Reference Genes for Normalization of miRNA Expression in Grafted Watermelon Plants under Different Nutrient Stresses.

    Science.gov (United States)

    Wu, Weifang; Deng, Qin; Shi, Pibiao; Yang, Jinghua; Hu, Zhongyuan; Zhang, Mingfang

    2016-01-01

    Watermelon (Citrullus lanatus) is a globally important crop belonging to the family Cucurbitaceae. The grafting technique is commonly used to improve its tolerance to stress, as well as to enhance its nutrient uptake and utilization. It is believed that miRNA is most likely involved in its nutrient-starvation response as a graft-transportable signal. The quantitative real-time reverse transcriptase polymerase chain reaction is the preferred method for miRNA functional analysis, in which reliable reference genes for normalization are crucial to ensure the accuracy. The purpose of this study was to select appropriate reference genes in scion (watermelon) and rootstocks (squash and bottle gourd) of grafted watermelon plants under normal growth conditions and nutrient stresses (nitrogen and phosphorus starvation). Under nutrient starvation, geNorm identified miR167c and miR167f as two most stable genes in both watermelon leaves and squash roots. miR166b was recommended by both geNorm and NormFinder as the best reference in bottle gourd roots under nutrient limitation. Expression of a new Cucurbitaceae miRNA, miR85, was used to validate the reliability of candidate reference genes under nutrient starvation. Moreover, by comparing several target genes expression in qRT-PCR analysis with those in RNA-seq data, miR166b and miR167c were proved to be the most suitable reference genes to normalize miRNA expression under normal growth condition in scion and rootstock tissues, respectively. This study represents the first comprehensive survey of the stability of miRNA reference genes in Cucurbitaceae and provides valuable information for investigating more accurate miRNA expression involving grafted watermelon plants.

  14. Modeling and stress analyses of a normal foot-ankle and a prosthetic foot-ankle complex.

    Science.gov (United States)

    Ozen, Mustafa; Sayman, Onur; Havitcioglu, Hasan

    2013-01-01

    Total ankle replacement (TAR) is a relatively new concept and is becoming more popular for treatment of ankle arthritis and fractures. Because of the high costs and difficulties of experimental studies, the developments of TAR prostheses are progressing very slowly. For this reason, the medical imaging techniques such as CT, and MR have become more and more useful. The finite element method (FEM) is a widely used technique to estimate the mechanical behaviors of materials and structures in engineering applications. FEM has also been increasingly applied to biomechanical analyses of human bones, tissues and organs, thanks to the development of both the computing capabilities and the medical imaging techniques. 3-D finite element models of the human foot and ankle from reconstruction of MR and CT images have been investigated by some authors. In this study, data of geometries (used in modeling) of a normal and a prosthetic foot and ankle were obtained from a 3D reconstruction of CT images. The segmentation software, MIMICS was used to generate the 3D images of the bony structures, soft tissues and components of prosthesis of normal and prosthetic ankle-foot complex. Except the spaces between the adjacent surface of the phalanges fused, metatarsals, cuneiforms, cuboid, navicular, talus and calcaneus bones, soft tissues and components of prosthesis were independently developed to form foot and ankle complex. SOLIDWORKS program was used to form the boundary surfaces of all model components and then the solid models were obtained from these boundary surfaces. Finite element analyses software, ABAQUS was used to perform the numerical stress analyses of these models for balanced standing position. Plantar pressure and von Mises stress distributions of the normal and prosthetic ankles were compared with each other. There was a peak pressure increase at the 4th metatarsal, first metatarsal and talus bones and a decrease at the intermediate cuneiform and calcaneus bones, in

  15. Maprotiline treatment differentially influences cardiac β-adrenoreceptors expression under normal and stress conditions

    Directory of Open Access Journals (Sweden)

    Natasa Spasojevic

    2012-12-01

    Full Text Available Alterations in cardiac function were observed in antidepressants treated patients and published in several clinical reports. These detected changes could be either a consequence of the treatment or of depression itself, which has already been proved to be a risk factor in heart diseases. In order to determine a possible influence of chronic treatment with norepinephrinergic reuptake inhibitor, maprotiline, on the heart, we investigated gene expression of cardiac β-adrenoceptors both in controls and in animals with signs of depression. The rats were divided into two groups, unstressed controls and those exposed to chronic unpredictable mild stress (CUMS. The groups were further divided into two subgroups, one receiving daily intraperitoneal injections of vehicle (sterile water and another one maprotiline (10 mg/kg for four weeks. Tissue samples were collected after the last application. Gene expression of cardiac β1- and β2-adrenoceptor was determined using Real-time RT-PCR analysis. Our results show that in control animals expression of both adrenoreceptors was decreased in the right atria after 4 weeks of maprotiline application. Contrary, the same treatment led to a significant increase in expression of cardiac β1-adrenoceptor in the stressed rats, with no change in the characteristics of β2-adrenoceptor. Our findings might reflect the that molecular mechanisms are underlying factors involved in the development of cardiovascular diseases linked with antidepressant treatment.

  16. Plasma, salivary and urinary cortisol levels following physiological and stress doses of hydrocortisone in normal volunteers.

    Science.gov (United States)

    Jung, Caroline; Greco, Santo; Nguyen, Hanh H T; Ho, Jui T; Lewis, John G; Torpy, David J; Inder, Warrick J

    2014-11-26

    Glucocorticoid replacement is essential in patients with primary and secondary adrenal insufficiency, but many patients remain on higher than recommended dose regimens. There is no uniformly accepted method to monitor the dose in individual patients. We have compared cortisol concentrations in plasma, saliva and urine achieved following "physiological" and "stress" doses of hydrocortisone as potential methods for monitoring glucocorticoid replacement. Cortisol profiles were measured in plasma, saliva and urine following "physiological" (20 mg oral) or "stress" (50 mg intravenous) doses of hydrocortisone in dexamethasone-suppressed healthy subjects (8 in each group), compared to endogenous cortisol levels (12 subjects). Total plasma cortisol was measured half-hourly, and salivary cortisol and urinary cortisol:creatinine ratio were measured hourly from time 0 (between 0830 and 0900) to 5 h. Endogenous plasma corticosteroid-binding globulin (CBG) levels were measured at time 0 and 5 h, and hourly from time 0 to 5 h following administration of oral or intravenous hydrocortisone. Plasma free cortisol was calculated using Coolens' equation. Plasma, salivary and urine cortisol at 2 h after oral hydrocortisone gave a good indication of peak cortisol concentrations, which were uniformly supraphysiological. Intravenous hydrocortisone administration achieved very high 30 minute cortisol concentrations. Total plasma cortisol correlated significantly with both saliva and urine cortisol after oral and intravenous hydrocortisone (P cortisol and urinary cortisol:creatinine ratio may provide useful alternatives to plasma cortisol measurements to monitor replacement doses in hypoadrenal patients.

  17. Rectification of pulsatile stress on soft tissues: a mechanism for normal-pressure hydrocephalus

    Science.gov (United States)

    Jalikop, Shreyas; Hilgenfeldt, Sascha

    2011-11-01

    Hydrocephalus is a pathological condition of the brain that occurs when cerebrospinal fluid (CSF) accumulates excessively in the brain cavities, resulting in compression of the brain parenchyma. Counter-intuitively, normal-pressure hydrocephalus (NPH) does not show elevated pressure differences across the compressed parenchyma. We investigate the effects of nonlinear tissue mechanics and periodic driving in this system. The latter is due to the cardiac cycle, which provides significant intracranial pressure and volume flow rate fluctuations. Nonlinear rectification of the periodic driving within a model of fluid flow in poroelastic material can lead to compression or expansion of the parenchyma, and this effect does not rely on changes in the mean intracranial pressure. The rectification effects can occur gradually over several days, in agreement with clinical studies of NPH.

  18. Evaluation of candidate reference genes for normalization of quantitative RT-PCR in soybean tissues under various abiotic stress conditions.

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    Dung Tien Le

    Full Text Available Quantitative RT-PCR can be a very sensitive and powerful technique for measuring differential gene expression. Changes in gene expression induced by abiotic stresses are complex and multifaceted, which make determining stably expressed genes for data normalization difficult. To identify the most suitable reference genes for abiotic stress studies in soybean, 13 candidate genes collected from literature were evaluated for stability of expression under dehydration, high salinity, cold and ABA (abscisic acid treatments using delta CT and geNorm approaches. Validation of reference genes indicated that the best reference genes are tissue- and stress-dependent. With respect to dehydration treatment, the Fbox/ABC, Fbox/60s gene pairs were found to have the highest expression stability in the root and shoot tissues of soybean seedlings, respectively. Fbox and 60s genes are the most suitable reference genes across dehydrated root and shoot tissues. Under salt stress the ELF1b/IDE and Fbox/ELF1b are the most stably expressed gene pairs in roots and shoots, respectively, while 60s/Fbox is the best gene pair in both tissues. For studying cold stress in roots or shoots, IDE/60s and Fbox/Act27 are good reference gene pairs, respectively. With regard to gene expression analysis under ABA treatment in either roots, shoots or across these tissues, 60s/ELF1b, ELF1b/Fbox and 60s/ELF1b are the most suitable reference genes, respectively. The expression of ELF1b/60s, 60s/Fbox and 60s/Fbox genes was most stable in roots, shoots and both tissues, respectively, under various stresses studied. Among the genes tested, 60s was found to be the best reference gene in different tissues and under various stress conditions. The highly ranked reference genes identified from this study were proved to be capable of detecting subtle differences in expression rates that otherwise would be missed if a less stable reference gene was used.

  19. GENETIC VARIABILITY OF CULTURED PLANT TISSUES UNDER NORMAL CONDITIONS AND UNDER STRESS

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    Dolgikh Yu.I.

    2012-08-01

    , the same mechanisms determine both in vitro and in vivo variability. Stress during tissue culture can induce somaclonal variation. For example during cryopreservation the callus cells experience stress caused by exposure to a complex of various factors, which may induce free radical formation and provide conditions for the appearance of genetic changes. ISSR and retrotransposon-microsatellite amplified polymorphism (REMAP markers were applied to study the influence of individual steps of dehydration cryopreservation technique on DNA in calli and regenerated plants of bread wheat. The precultivation with sucrose and freezing had no influence on the genetic stability of plant material. After the dehydration step, a new fragment appeared in the REMAP profiles for one DNA sample in calli of one line. The most likely cause of the this change is triggered by the stress experienced by cells during dehydration, insertion of a new copy of retrotransposon close to the microsatellite sequence complementary to the ISSR primer.

  20. How Might Draining Lake Campotosto Affect Stress and Seismicity on the Monte Gorzano Normal Fault, Central Italy?

    Science.gov (United States)

    Verdecchia, A.; Deng, K.; Harrington, R. M.; Liu, Y.

    2017-12-01

    It is broadly accepted that large variations of water level in reservoirs may affect the stress state on nearby faults. While most studies consider the relationship between lake impoundment and the occurrence of large earthquakes or seismicity rate increases in the surrounding region, very few examples focus on the effects of lake drainage. The second largest reservoir in Europe, Lake Campotosto, is located on the hanging wall of the Monte Gorzano fault, an active normal fault responsible for at least two M ≥ 6 earthquakes in historical times. The northern part of this fault ruptured during the August 24, 2016, Mw 6.0 Amatrice earthquake, increasing the probability for a future large event on the southern section where an aftershock sequence is still ongoing. The proximity of the Campotosto reservoir to the active fault aroused general concern with respect to the stability of the three dams bounding the reservoir if the southern part of the Monte Gorzano fault produces a moderate earthquake. Local officials have proposed draining the reservoir as hazard mitigation strategy to avoid possible future catastrophes. In efforts to assess how draining the reservoir might affect earthquake nucleation on the fault, we use a finite-element poroelastic model to calculate the evolution of stress and pore pressure in terms of Coulomb stress changes that would be induced on the Monte Gorzano fault by emptying the Lake Campotosto reservoir. Preliminary results show that an instantaneous drainage of the lake will produce positive Coulomb stress changes, mostly on the shallower part of the fault (0 to 2 km), while a stress drop of the order of 0.2 bar is expected on the Monte Gorzano fault between 0 and 8 km depth. Earthquake hypocenters on the southern portion of the fault currently nucleate between 5 and 13 km depth, with activity distributed nearby the reservoir. Upcoming work will model the effects of varying fault geometry and elastic parameters, including geological

  1. Parental Perceptions of Child Behavior Problems, Parenting Self-Esteem, and Mothers' Reported Stress in Younger and Older Hyperactive and Normal Children.

    Science.gov (United States)

    Mash, Eric J.; Johnston, Charlotte

    1983-01-01

    Examined parental perceptions of child behavior, parenting self-esteem, and mothers' reported stress for younger and older hyperactive and normal children. Parenting self-esteem was lower in parents of hyperactives than in parents of normal children. Self-esteem related to skill/knowledge as a parent was age related. (Author/RC)

  2. Investigation of cytokines, oxidative stress, metabolic, and inflammatory biomarkers after orange juice consumption by normal and overweight subjects

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    Grace K. Z. S. Dourado

    2015-10-01

    Full Text Available Background: Abdominal adiposity has been linked to metabolic abnormalities, including dyslipidemia, oxidative stress, and low-grade inflammation. Objective: To test the hypothesis that consumption of 100% orange juice (OJ would improve metabolic, oxidative, and inflammatory biomarkers and cytokine levels in normal and overweight subjects with increased waist circumference. Design: Subjects were divided into two groups in accordance with their body mass index: normal and overweight. Both groups of individuals consumed 750 mL of OJ daily for 8 weeks. Body composition (weight, height, percentage of fat mass, and waist circumference; metabolic biomarkers (total cholesterol, low-density lipoprotein-cholesterol [LDL-C], high-density lipoprotein-cholesterol [HDL-C], triglycerides, glucose, insulin, HOMA-IR, and glycated hemoglobin; oxidative biomarkers (malondialdehyde and DPPH•; inflammatory biomarkers (high-sensitivity C-reactive protein [hsCRP]; cytokines (IL-4, IL-10, IL-12, TNF-α, and IFN-γ; and diet were evaluated before and after consumption of OJ for 8 weeks. Results: The major findings of this study were: 1 no alteration in body composition in either group; 2 improvement of the lipid profile, evidenced by a reduction in total cholesterol and LDL-C; 3 a potential stimulation of the immune response due to increase in IL-12; 4 anti-inflammatory effect as a result of a marked reduction in hsCRP; and 5 antioxidant action by the enhancement of total antioxidant capacity and the reduction of lipid peroxidation, in both normal and overweight subjects. Conclusions: OJ consumption has a positive effect on important biomarkers of health status in normal and overweight subjects, thereby supporting evidence that OJ acts as functional food and could be consumed as part of a healthy diet to prevent metabolic and chronic diseases.

  3. Dry Matter Accumulation and Remobilization in Grain Sorghum Genotypes (Sorghum bicolor L. Moench (underNormal and Water Stress Conditions

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    A Beheshti

    2011-02-01

    Full Text Available Abstract Production, remobilization and accumulation of assimilates in crops especially under water stress are essential factors for determination and studying the yield differences of species and cultivars. Field experiment was conducted using a split plot design based on a randomized complete block design with 3 replication s during 2007 growing season in agricultural research station (Khorasan Agricultural and Natural Resource Research Center, Mashhad-Iran. Main plots were consisted of 2 levels of water, water deficit after anthesis and normal condition (with out water stress and factorial arrangement of photosynthesis status (non desiccation and chemical desiccation with potassium iodide and 3 grain sorghum genotypes (Sepide, M5 and M2 promising lines were assigned to sub plots. Results of variance analysis showed, that the effects of water stress on dry matter accumulation, efficiency of remobilization (REE, percent of remobilization (REP, biologic yield were significant in (p≤0.01 (and grain yield (economic yield was significant in p≤0.05, respectively. Water deficit caused an increase of 10.08%, 24.45 % and 12.43% in dry matter accumulation, percent of remobilization and efficiency of remobilization, respectively as compared to normal conditions. This in turn was led to decrease in seed yield, biological yield and harvest index by 36.38%, 5.43% and 31.60%, respectively. The effect of disturbance in current photosynthesis was significant in all of traits and caused the increase of 15.58%, 17.5% and 36.62% in dry matter accumulation, efficiency of remobilization and percent of remobilization, respectively. The role of remobilization was crucial in sorghum genotypes. Interaction between factors showed that highest dry matter accumulation, percentage of remobilization and efficiency of remobilization was in drought stress and disturbance in current photosynthesis and was 16.62%, 62.54 and 24.60%, respectively and was significantly

  4. Difference in the craniocaudal gradient of the maximum pixel value change rate between chronic obstructive pulmonary disease patients and normal subjects using sub-mGy dynamic chest radiography with a flat panel detector system.

    Science.gov (United States)

    Yamada, Yoshitake; Ueyama, Masako; Abe, Takehiko; Araki, Tetsuro; Abe, Takayuki; Nishino, Mizuki; Jinzaki, Masahiro; Hatabu, Hiroto; Kudoh, Shoji

    2017-07-01

    To compare the craniocaudal gradients of the maximum pixel value change rate (MPCR) during tidal breathing between chronic obstructive pulmonary disease (COPD) patients and normal subjects using dynamic chest radiography. This prospective study was approved by the institutional review board and all participants provided written informed consent. Forty-three COPD patients (mean age, 71.6±8.7 years) and 47 normal subjects (non-smoker healthy volunteers) (mean age, 54.8±9.8 years) underwent sequential chest radiographs during tidal breathing in a standing position using dynamic chest radiography with a flat panel detector system. We evaluated the craniocaudal gradient of MPCR. The results were analyzed using an unpaired t-test and the Tukey-Kramer method. The craniocaudal gradients of MPCR in COPD patients were significantly lower than those in normal subjects (right inspiratory phase, 75.5±48.1 vs. 108.9±42.0s -1 cm -1 , P<0.001; right expiratory phase, 66.4±40.6 vs. 89.8±31.6s -1 cm -1 , P=0.003; left inspiratory phase, 75.5±48.2 vs. 108.2±47.2s -1 cm -1 , P=0.002; left expiratory phase, 60.9±38.2 vs. 84.3±29.5s -1 cm -1 , P=0.002). No significant differences in height, weight, or BMI were observed between COPD and normal groups. In the sub-analysis, the gradients in severe COPD patients (global initiative for chronic obstructive lung disease [GOLD] 3 or 4, n=26) were significantly lower than those in mild COPD patients (GOLD 1 or 2, n=17) for both right and left inspiratory/expiratory phases (all P≤0.005). A decrease of the craniocaudal gradient of MPCR was observed in COPD patients. The craniocaudal gradient was lower in severe COPD patients than in mild COPD patients. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  5. Phenological Variation and its Relation with Yield in several Wheat (Triticum aestivum L. Cultivars under Normal and Late Sowing Mediated Heat Stress Condition

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    Kamrun NAHAR

    2010-09-01

    Full Text Available Phenological performance in relation to yield of five modern varieties of wheat Sourav, Pradip, Sufi, Shatabdi and Bijoy were evaluated under two growing environments; one is normal growing environment (sowing at November 30 and the other is post anthesis heat stressed environment (sowing at December 30. In case of late seeding, the varieties phased a significant level of high temperature stress that also significantly affected the required days to germination, booting, anthesis, maturity of all varieties including the yield as compared to normal sowing treatment. The temperature during the grain filling or grain maturing period was near 23C in case of normal seeding and it was near about 28C to 30C and sometimes reached above this range in the later period of late seeded treatment. In the normal sowing treatment the germination period was lower than the late sowing treatment as during that time the temperature was higher as compared to late sowing condition where temperature was lower. Days to anthesis and booting decreased due to late sown heat stress condition regardless the cultivars. These phenological characteristics under heat stressed condition led the wheat cultivars to significantly lower the grain yield as compared to normal condition. Due to heat stress, the yield reduction was 69.53% in Sourav, 58.41% in Pradip, 73.01% in Sufi, 55.46% in Shatabdi and 53.42% in Bijoy.

  6. Identification, Expression Analysis, and Target Prediction of Flax Genotroph MicroRNAs Under Normal and Nutrient Stress Conditions

    Science.gov (United States)

    Melnikova, Nataliya V.; Dmitriev, Alexey A.; Belenikin, Maxim S.; Koroban, Nadezhda V.; Speranskaya, Anna S.; Krinitsina, Anastasia A.; Krasnov, George S.; Lakunina, Valentina A.; Snezhkina, Anastasiya V.; Sadritdinova, Asiya F.; Kishlyan, Natalya V.; Rozhmina, Tatiana A.; Klimina, Kseniya M.; Amosova, Alexandra V.; Zelenin, Alexander V.; Muravenko, Olga V.; Bolsheva, Nadezhda L.; Kudryavtseva, Anna V.

    2016-01-01

    Cultivated flax (Linum usitatissimum L.) is an important plant valuable for industry. Some flax lines can undergo heritable phenotypic and genotypic changes (LIS-1 insertion being the most common) in response to nutrient stress and are called plastic lines. Offspring of plastic lines, which stably inherit the changes, are called genotrophs. MicroRNAs (miRNAs) are involved in a crucial regulatory mechanism of gene expression. They have previously been assumed to take part in nutrient stress response and can, therefore, participate in genotroph formation. In the present study, we performed high-throughput sequencing of small RNAs (sRNAs) extracted from flax plants grown under normal, phosphate deficient and nutrient excess conditions to identify miRNAs and evaluate their expression. Our analysis revealed expression of 96 conserved miRNAs from 21 families in flax. Moreover, 475 novel potential miRNAs were identified for the first time, and their targets were predicted. However, none of the identified miRNAs were transcribed from LIS-1. Expression of seven miRNAs (miR168, miR169, miR395, miR398, miR399, miR408, and lus-miR-N1) with up- or down-regulation under nutrient stress (on the basis of high-throughput sequencing data) was evaluated on extended sampling using qPCR. Reference gene search identified ETIF3H and ETIF3E genes as most suitable for this purpose. Down-regulation of novel potential lus-miR-N1 and up-regulation of conserved miR399 were revealed under the phosphate deficient conditions. In addition, the negative correlation of expression of lus-miR-N1 and its predicted target, ubiquitin-activating enzyme E1 gene, as well as, miR399 and its predicted target, ubiquitin-conjugating enzyme E2 gene, was observed. Thus, in our study, miRNAs expressed in flax plastic lines and genotrophs were identified and their expression and expression of their targets was evaluated using high-throughput sequencing and qPCR for the first time. These data provide new insights

  7. Translocation of 14C-photosynthates under normal and moisture stress conditions in finger millet (Eleusine coracana) gaertin

    International Nuclear Information System (INIS)

    Udayakumar, M.; Rama Rao, S.; Krishna Sastry, K.S.

    1981-01-01

    Translocation of photosynthates into different sinks was studied following feeding a single leaf with 14 CO 2 in 40 day old stressed and non-stressed plants of Eleusine coracana. The rate of efflux of 14 C-photosynthates was twice as much in non-stressed plants compared to stressed plants. Young developing leaves, stem apex and stem which are the potential sinks under non-stressed conditions received very little activity under stress conditions. Percent activity in the roots was enhanced under stress suggesting the pattern of translocation was altered under stress conditions. In the plants subjected to moisture stress, after feeding with 14 CO 2 the rate of efflux of 14 C-photosynthates from the fed leaf decreased and the pattern of translocation was altered. Though the effect of stress seems to be directly on the translocation system, the photosynthetic rate appears to be more sensitive to stress than translocation. (author)

  8. Argirein alleviates stress-induced and diabetic hypogonadism in rats via normalizing testis endothelin receptor A and connexin 43.

    Science.gov (United States)

    Xu, Ming; Hu, Chen; Khan, Hussein-hamed; Shi, Fang-hong; Cong, Xiao-dong; Li, Qing; Dai, Yin; Dai, De-zai

    2016-02-01

    Argirein (rhein-arginine) is a derivative of rhein isolated from Chinese rhubarb (Rheum Officinale Baill.) that exhibits antioxidant and anti-inflammatory activities. In the present study we investigated the effects of argirein on stress-induced (hypergonadotrophic) and diabetic (hypogonadotrophic) hypogonadism in male rats. Stress-induced and diabetic hypogonadism was induced in male rats via injection of isoproterenol (ISO) or streptozotocin (STZ). ISO-injected rats were treated with argirein (30 mg·kg(-1)·d(-1), po) or testosterone replacement (0.5 mg·kg(-1)·d(-1), sc) for 5 days, and STZ-injected rats were treated with argirein (40-120 mg·kg(-1)·d(-1), po) or aminoguanidine (100 mg·kg(-1)·d(-1), po) for 4 weeks. After the rats were euthanized, blood samples and testes were collected. Serum hormone levels were measured, and the expression of endothelin receptor A (ETA), connexin 43 (Cx43) and other proteins in testes was detected. For in vitro experiments, testis homogenate was prepared from normal male rats, and incubated with ISO (1 μmol/L) or high glucose (27 mmol/L). ISO injection induced hyper-gonadotrophic hypogonadism characterized by low testosterone and high FSH and LH levels in the serum, whereas STZ injection induced hypogonadotrophic hypogonadism as evidenced by low testosterone and low FSH and LH levels in the serum. In the testes of ISO- and STZ-injected rats, the expression of ETA, MMP-9, NADPH oxidase and pPKCε was significantly increased, and the expression of Cx43 was decreased. Administration of argirein attenuated both the abnormal serum hormone levels and the testis changes in ISO- and STZ-injected rats, and aminoguanidine produced similar actions in STZ-injected rats; testosterone replacement reversed the abnormal serum hormone levels, but did not affect the testis changes in ISO-injected rats. Argirein (0.3-3 μmol/L) exerted similar effects in testis homogenate incubated with ISO or high glucose in vitro. Two types of

  9. Technetium 99m SESTAMIBI myocardial perfusion imaging: Comparison between treadmill, dipyridamole and trans-oesophageal atrial pacing 'stress' tests in normal subjects

    International Nuclear Information System (INIS)

    Primeau, M.; Taillefer, R.; Lambert, R.; Essiambre, R.; Honos, G.

    1991-01-01

    The purpose of this study was to determine the blood clearance, myocardial uptake and heart/lung and heart/liver ratios of technetium 99m methoxyisobutylisonitrile ( 99m Tc-SESTAMIBI) following 3 different types of cardiac stimulation in normal subjects: Treadmill stress (STRESS), intravenous administration of dipyridamole (DIP) and trans-oesophageal atrial pacing (TAP). Ten normal volunteers were submitted to 3 injections of 99m Tc-SESTAMIBI (10 mCi/70 kg, separated by an interval of 7 days) following STRESS (standard Bruce protocol), DIP (0.142 mg/kg.min during 4 min) and TAP procedures. Blood samples were collected from 1 to 60 min after each 99m Tc-SESTAMIBI injection. Planar imaging was performed at 5, 30 and 60 min. Blood retention (percentage of injected dose at 1 min) was 56%±4%, 24%±4% and 38%±6% for STRESS, DIP and TAP, respectively (P 99m Tc-SESTAMIBI. (orig.)

  10. Hearts of dystonia musculorum mice display normal morphological and histological features but show signs of cardiac stress.

    Directory of Open Access Journals (Sweden)

    Justin G Boyer

    2010-03-01

    Full Text Available Dystonin is a giant cytoskeletal protein belonging to the plakin protein family and is believed to crosslink the major filament systems in contractile cells. Previous work has demonstrated skeletal muscle defects in dystonin-deficient dystonia musculorum (dt mice. In this study, we show that the dystonin muscle isoform is localized at the Z-disc, the H zone, the sarcolemma and intercalated discs in cardiac tissue. Based on this localization pattern, we tested whether dystonin-deficiency leads to structural defects in cardiac muscle. Desmin intermediate filament, microfilament, and microtubule subcellular organization appeared normal in dt hearts. Nevertheless, increased transcript levels of atrial natriuretic factor (ANF, 66% beta-myosin heavy chain (beta-MHC, 95% and decreased levels of sarcoplasmic reticulum calcium pump isoform 2A (SERCA2a, 26%, all signs of cardiac muscle stress, were noted in dt hearts. Hearts from two-week old dt mice were assessed for the presence of morphological and histological alterations. Heart to body weight ratios as well as left ventricular wall thickness and left chamber volume measurements were similar between dt and wild-type control mice. Hearts from dt mice also displayed no signs of fibrosis or calcification. Taken together, our data provide new insights into the intricate structure of the sarcomere by situating dystonin in cardiac muscle fibers and suggest that dystonin does not significantly influence the structural organization of cardiac muscle fibers during early postnatal development.

  11. Reference Gene Selection for qRT-PCR Normalization Analysis in kenaf (Hibiscus cannabinus L. under Abiotic Stress and Hormonal Stimuli

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    Xiaoping Niu

    2017-05-01

    Full Text Available Kenaf (Hibiscus cannabinus L., an environmental friendly and economic fiber crop, has a certain tolerance to abiotic stresses. Identification of reliable reference genes for transcript normalization of stress responsive genes expression by quantitative real-time PCR (qRT-PCR is important for exploring the molecular mechanisms of plants response to abiotic stresses. In this study, nine candidate reference genes were cloned, and their expression stabilities were assessed in 132 abiotic stress and hormonal stimuli samples of kenaf using geNorm, NormFinder, and BestKeeper algorithms. Results revealed that HcPP2A (Protein phosphatase 2A and HcACT7 (Actin 7 were the optimum reference genes across all samples; HcUBC (Ubiquitin-conjugating enzyme like protein was the worst reference gene for transcript normalization. The reliability of the selected reference genes was further confirmed by evaluating the expression profile of HcWRKY28 gene at different stress durations. This work will benefit future studies on discovery of stress-tolerance genes and stress-signaling pathways in this important fiber crop.

  12. COMPARISON OF STRESS LEVELS IN THE PARENTS OF CHILDREN WITH CEREBRAL PALSY AND PARENTS OF NORMAL CHILDREN IN VADODARA REGION OF GUJARAT

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    Dr. Vivek H. Ramanandi

    2015-04-01

    Full Text Available Background: Parenting is inherently stressful at times and several studies have shown that being a caregiver of a child who is disabled is even more stressful. A number of studies have identified the factors which exacerbate or mediate parenting stress in caregivers of children who are disabled. The aim of this study was to assess the parenting stress levels in parents of children who have cerebral palsy as compared to parents of normal children. Further objectives were to ascertain variables predictive of parenting stress levels. Methods: The Gujarati translated version of Parenting Stress Index/Short Form was first validated and was given to 49 parents of children with cerebral palsy (Group-A who were attending Varun Mahajan Apang Shishu Mandal, Vadodara and to the 50 parents of normal children(Group-B. Caregivers also completed a demographic questionnaire. 43 questionnaires from Group-A and 45 from Group-B were returned to the researcher. Means and frequencies were used to summarise the demographic data. T-tests were performed to establish whether there was any significant difference between the parenting stress levels in Group-A and Group-B. Results: The parents in Group-A showed clinically significant, and in many cases, pathological levels of parenting stress as compared to the parents in Group-B. Conclusions: The results of this study confirm that parenting stress is complex matter and it is important to predict the parenting stress levels of caregivers of disabled children. Therapists should evaluate the needs of each family individually and follow a family centred approach when managing children with cerebral palsy.

  13. Normal stress-only myocardial single photon emission computed tomography predicts good outcome in patients with coronary artery stenoses between 40 and 70.

    Science.gov (United States)

    Jiang, Zhixin; Liu, Yangqing; Xin, Chaofan; Zhou, Yanli; Wang, Cheng; Zhao, Zhongqiang; Li, Chunxiang; Li, Dianfu

    2016-09-01

    Normal stress myocardial single photon emission computed tomography (SPECT) usually indicates good physiologic function of all coronary lesions, and also indicates a good outcome. We hypothesize that it can still predict good outcome in patients with coronary stenoses between 40 and 70%. A group of patients who underwent stress myocardial SPECT after coronary angiography were consecutively recruited in our center. Patients were eligible if they had one or more coronary stenoses between 40 and 70%. Patients with coronary stenoses greater than 50% diameter of left main or greater than 70% diameter of nonleft main epicardial vessels, and left ventricular ejection fraction less than 50% were excluded. The outcome was defined as major adverse events, including cardiac death, nonfatal myocardial infarction, and revascularization. Patients' survival curves were constructed accorded to the method of Kaplan and Meier and compared using the log-rank test. A study cohort of 77 patients was enrolled. According to the summed stress score, 43 patients were assigned to the perfusion defect group and 34 patients were assigned to the perfusion normal group. The follow-up duration was 6.4±0.3 years. In the perfusion normal group, only one of 34 (2.9%) patients developed major adverse events. In the perfusion defect group, six of 43 (14%) developed major adverse events, P-value of 0.041. It is safe to defer a percutaneous coronary intervention in patients with coronary stenoses between 40 and 70% and normal stress myocardial SPECT.

  14. Influence of Normal and Shear Stress on the Hydraulic Transmissivity of Thin Cracks in a Tight Quartz Sandstone, a Granite, and a Shale

    Science.gov (United States)

    Rutter, Ernest H.; Mecklenburgh, Julian

    2018-02-01

    Transmissivity of fluids along fractures in rocks is reduced by increasing normal stress acting across them, demonstrated here through gas flow experiments on Bowland shale, and oil flow experiments on Pennant sandstone and Westerly granite. Additionally, the effect of imposing shear stress at constant normal stress was determined, until frictional sliding started. In all cases, increasing shear stress causes an accelerating reduction of transmissivity by 1 to 3 orders of magnitude as slip initiated, as a result of the formation of wear products that block fluid pathways. Only in the case of granite, and to a lesser extent in the sandstone, was there a minor amount of initial increase of transmissivity prior to the onset of slip. These results cast into doubt the commonly applied presumption that cracks with high resolved shear stresses are the most conductive. In the shale, crack transmissivity is commensurate with matrix permeability, such that shales are expected always to be good seals. For the sandstone and granite, unsheared crack transmissivity was respectively 2 and 2.5 orders of magnitude greater than matrix permeability. For these rocks crack transmissivity can dominate fluid flow in the upper crust, potentially enough to permit maintenance of a hydrostatic fluid pressure gradient in a normal (extensional) faulting regime.

  15. Normalized wall index specific and MRI-based stress analysis of atherosclerotic carotid plaques. A study comparing acutely symptomatic and asymptomatic patients

    International Nuclear Information System (INIS)

    Zhu, C.; Teng, Z.; Sadat, U.; Young, V.E.; Graves, M.J.; Gillard, J.H.; Li Zhiyong

    2010-01-01

    Biomechanical stresses play an important role in determining plaque stability. Quantification of these simulated stresses can be potentially used to assess plaque vulnerability and differentiate different patient groups. 54 asymptomatic and 45 acutely symptomatic patients underwent in vivo multicontrast magnetic resonance imaging (MRI) of the carotid arteries. Plaque geometry used for finite element analysis was derived from in vivo MRI at the sites of maximum and minimum plaque burden. In total, 198 slices were used for the computational simulations. A pre-shrink technique was used to refine the simulation. Maximum principle stress at the vulnerable plaque sites (id est (ie), critical stress) was extracted for the selected slices and a comparison was performed between the 2 groups. Critical stress in the slice with maximum plaque burden is significantly higher in acutely symptomatic patients as compared to asymptomatic patients (median, inter quartile range: 198.0 kPa (119.8-359.0 kPa) vs 138.4 kPa (83.8-242.6 kPa), P=0.04). No significant difference was found in the slice with minimum plaque burden between the 2 groups (196.7 kPa (133.3-282.7 kPa) vs 182.4 kPa (117.2-310.6 kPa), P=0.82). Acutely symptomatic carotid plaques have significantly high biomechanical stresses than asymptomatic plaques. This might be potentially useful for establishing a biomechanical risk stratification criteria based on plaque burden in future studies. (author)

  16. Myocardial uptake and clearance of thallium-201 in normal subjects: comparison of dipyridamole-induced hyperemia with exercise stress

    International Nuclear Information System (INIS)

    Ruddy, T.D.; Gill, J.B.; Finkelstein, D.M.; Strauss, H.W.; McKusick, K.A.; Okada, R.D.; Boucher, C.A.

    1987-01-01

    Thallium-201 uptake and clearance after dipyridamole infusion may differ from that after exercise stress because the hemodynamic effects of these two interventions are different. In this study of normal volunteers, thallium kinetics after dipyridamole (n = 13) were determined from three serial image sets (early, intermediate and delayed) and from serial blood samples and compared with thallium kinetics after exercise (n = 15). Absolute myocardial thallium uptake was greater after dipyridamole compared with exercise (p less than 0.0001), although the relative myocardial distribution was similar. The myocardial clearance (%/h) of thallium was slower after dipyridamole than it was after exercise. Comparing dipyridamole and exercise, the differences in clearance were large from the early to the intermediate image (anterior, -11 +/- 17 versus 24 +/- 5, p = 0.0005; 50 degrees left anterior oblique, -7 +/- 11 versus 15 +/- 8, p = 0.004; 70 degrees left anterior oblique, 3 +/- 9 versus 21 +/- 6, p = 0.001). In contrast, the differences in clearance were small from the intermediate to the delayed image (anterior, 15 +/- 4 versus 20 +/- 2, p = 0.025; 50 degrees left anterior oblique, 15 +/- 4 versus 19 +/- 3, p = 0.13; 70 degrees left anterior oblique, 15 +/- 3 versus 18 +/- 2, p = 0.047). Thallium uptake and clearance in the liver, splanchnic region and spleen were greater after dipyridamole (p less than 0.001). Blood thallium levels were greater after dipyridamole (p less than 0.05) and cleared more slowly (p = 0.07). Thus, myocardial thallium-201 uptake and clearance after dipyridamole infusion differ from thallium kinetics after exercise. This difference is, in part, related to associated differences in extracardiac and blood kinetics. Diagnostic criteria for the detection of abnormal thallium-201 clearance must be specific for the type of intervention

  17. Phenological Variation and its Relation with Yield in several Wheat (Triticum aestivum L. Cultivars under Normal and Late Sowing Mediated Heat Stress Condition

    Directory of Open Access Journals (Sweden)

    Kamrun NAHAR

    2010-09-01

    Full Text Available Phenological performance in relation to yield of five modern varieties of wheat �Sourav�, �Pradip�, �Sufi�, �Shatabdi� and �Bijoy� were evaluated under two growing environments; one is normal growing environment (sowing at November 30 and the other is post anthesis heat stressed environment (sowing at December 30. In case of late seeding, the varieties phased a significant level of high temperature stress that also significantly affected the required days to germination, booting, anthesis, maturity of all varieties including the yield as compared to normal sowing treatment. The temperature during the grain filling or grain maturing period was near 23�C in case of normal seeding and it was near about 28�C to 30�C and sometimes reached above this range in the later period of late seeded treatment. In the normal sowing treatment the germination period was lower than the late sowing treatment as during that time the temperature was higher as compared to late sowing condition where temperature was lower. Days to anthesis and booting decreased due to late sown heat stress condition regardless the cultivars. These phenological characteristics under heat stressed condition led the wheat cultivars to significantly lower the grain yield as compared to normal condition. Due to heat stress, the yield reduction was 69.53% in �Sourav�, 58.41% in �Pradip�, 73.01% in �Sufi�, 55.46% in �Shatabdi� and 53.42% in �Bijoy�.

  18. In vivo imaging of oxidative stress in the kidney of diabetic mice and its normalization by angiotensin II type 1 receptor blocker

    International Nuclear Information System (INIS)

    Sonta, Toshiyo; Inoguchi, Toyoshi; Matsumoto, Shingo; Yasukawa, Keiji; Inuo, Mieko; Tsubouchi, Hirotaka; Sonoda, Noriyuki; Kobayashi, Kunihisa; Utsumi, Hideo; Nawata, Hajime

    2005-01-01

    This study was undertaken to evaluate oxidative stress in the kidney of diabetic mice by electron spin resonance (ESR) imaging technique. Oxidative stress in the kidney was evaluated as organ-specific reducing activity with the signal decay rates of carbamoyl-PROXYL probe using ESR imaging. The signal decay rates were significantly faster in corresponding image pixels of the kidneys of streptozotocin-induced diabetic mice than in those of controls. This technique further demonstrated that administration of angiotensin II type 1 receptor blocker (ARB), olmesartan (5 mg/kg), completely restored the signal decay rates in the diabetic kidneys to control values. In conclusion, this study provided for the first time the in vivo evidence for increased oxidative stress in the kidneys of diabetic mice and its normalization by ARB as evaluated by ESR imaging. This technique would be useful as a means of further elucidating the role of oxidative stress in diabetic nephropathy

  19. Stress-induced ST-segment deviation in relation to the presence and severity of coronary artery disease in patients with normal myocardial perfusion imaging.

    Science.gov (United States)

    Weinsaft, Jonathan W; Manoushagian, Shant J; Patel, Taral; Shakoor, Aqsa; Kim, Robert J; Mirchandani, Sunil; Lin, Fay; Wong, Franklin J; Szulc, Massimiliano; Okin, Peter M; Kligfield, Paul D; Min, James K

    2009-01-01

    To assess the utility of stress electrocardiography (ECG) for identifying the presence and severity of obstructive coronary artery disease (CAD) defined by coronary computed tomographic angiography (CCTA) among patients with normal nuclear myocardial perfusion imaging (MPI). The study population comprised 119 consecutive patients with normal MPI who also underwent CCTA (interval 3.5+/-3.8 months). Stress ECG was performed at the time of MPI. CCTA and MPI were interpreted using established scoring systems, and CCTA was used to define the presence and extent of CAD, which was quantified by a coronary artery jeopardy score. Within this population, 28 patients (24%) had obstructive CAD identified by CCTA. The most common CAD pattern was single-vessel CAD (61%), although proximal vessel involvement was present in 46% of patients. Patients with CAD were nearly three times more likely to have positive standard test responses (1 mm ST-segment deviation) than patients with patent coronary arteries (36 vs. 13%, P=0.007). In multivariate analysis, a positive ST-segment test response was an independent marker for CAD (odds ratio: 2.02, confidence interval: 1.09-3.78, P=0.03) even after adjustment for a composite of clinical cardiac risk factors (odds ratio: 1.85, confidence interval: 1.05-3.23, P=0.03). Despite uniformly normal MPI, mean coronary jeopardy score was three-fold higher among patients with positive compared to those with negative ST-segment response to exercise or dobutamine stress (1.9+/-2.7 vs. 0.5+/-1.4, P=0.03). Stress-induced ST-segment deviation is an independent marker for obstructive CAD among patients with normal MPI. A positive stress ECG identifies patients with a greater anatomic extent of CAD as quantified by coronary jeopardy score.

  20. HPA axis response to social stress is attenuated in schizophrenia but normal in depression: evidence from a meta-analysis of existing studies.

    Science.gov (United States)

    Ciufolini, Simone; Dazzan, Paola; Kempton, Matthew J; Pariante, Carmine; Mondelli, Valeria

    2014-11-01

    We conducted a meta-analysis to investigate the HPA axis response to social stress in studies that used the Trier Social Stress Test (TSST), or comparable distressing paradigms, in individuals with either depression or schizophrenia. Sample size-adjusted effect sizes (Hedge's g statistic) were calculated to estimate the HPA axis stress response to social stress. We used a meta-regression model to take into account the moderating effect of the baseline cortisol level. Participants with depression show an activation pattern to social stress similar to that of healthy controls. Despite a normal cortisol production rate, individuals with schizophrenia have lower cortisol levels than controls both in anticipation and after exposure to social stress. Participants with depression and higher cortisol levels before the task have an increased cortisol production and reached higher cortisol levels during the task. This may be explained by the presence of an impaired negative feedback. The activation pattern present in schizophrenia may explain the reduced ability to appropriately contextualize past experiences shown by individuals with psychosis in social stressful situation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Development of the apparatus for measuring magnetic properties of electrical steel sheets in arbitrary directions under compressive stress normal to their surface

    Directory of Open Access Journals (Sweden)

    Yoshitaka Maeda

    2017-05-01

    Full Text Available In designing motors, one must grasp the magnetic properties of electrical steel sheets considering actual conditions in motors. Especially important is grasping the stress dependence of magnetic power loss. This paper describes a newly developed apparatus to measure two-dimensional (2-D magnetic properties (properties under the arbitrary alternating and the rotating flux conditions of electrical steel sheets under compressive stress normal to the sheet surface. The apparatus has a 2-D magnetic excitation circuit to generate magnetic fields in arbitrary directions in the evaluation area. It also has a pressing unit to apply compressive stress normal to the sheet surface. During measurement, it is important to apply uniform stress throughout the evaluation area. Therefore, we have developed a new flux density sensor using needle probe method. It is composed of thin copper foils sputtered on electrical steel sheets. By using this sensor, the stress can be applied to the surface of the specimen without influence of this sensor. This paper described the details of newly developed apparatus with this sensor, and measurement results of iron loss by using are shown.

  2. Development of the apparatus for measuring magnetic properties of electrical steel sheets in arbitrary directions under compressive stress normal to their surface

    Science.gov (United States)

    Maeda, Yoshitaka; Urata, Shinya; Nakai, Hideo; Takeuchi, Yuuya; Yun, Kyyoul; Yanase, Shunji; Okazaki, Yasuo

    2017-05-01

    In designing motors, one must grasp the magnetic properties of electrical steel sheets considering actual conditions in motors. Especially important is grasping the stress dependence of magnetic power loss. This paper describes a newly developed apparatus to measure two-dimensional (2-D) magnetic properties (properties under the arbitrary alternating and the rotating flux conditions) of electrical steel sheets under compressive stress normal to the sheet surface. The apparatus has a 2-D magnetic excitation circuit to generate magnetic fields in arbitrary directions in the evaluation area. It also has a pressing unit to apply compressive stress normal to the sheet surface. During measurement, it is important to apply uniform stress throughout the evaluation area. Therefore, we have developed a new flux density sensor using needle probe method. It is composed of thin copper foils sputtered on electrical steel sheets. By using this sensor, the stress can be applied to the surface of the specimen without influence of this sensor. This paper described the details of newly developed apparatus with this sensor, and measurement results of iron loss by using are shown.

  3. Interaction between a normal shock wave and a turbulent boundary layer at high transonic speeds. Part 2: Wall shear stress

    Science.gov (United States)

    Liou, M. S.; Adamson, T. C., Jr.

    1979-01-01

    An analysis is presented of the flow in the two inner layers, the Reynolds stress sublayer and the wall layer. Included is the calculation of the shear stress at the wall in the interaction region. The limit processes considered are those used for an inviscid flow.

  4. Stress

    Science.gov (United States)

    ... can be life-saving. But chronic stress can cause both physical and mental harm. There are at least three different types of stress: Routine stress related to the pressures of work, family, and other daily responsibilities Stress brought about ...

  5. Ultimate stress increase in unbonded tendons in post-tensioned indeterminate I-beams cast with high strength normal and self compacting concrete

    Directory of Open Access Journals (Sweden)

    Yousef Askari Dolatabad

    2018-06-01

    Full Text Available The use of un-bonded tendons is prevalent in post-tensioned concrete structures. Equations for prediction of stress in un-bonded tendons of post-tensioned normal (vibrating concrete flexural members have been given in various codes. They are based on experience and don’t account all of important parameters such as concrete strength (normal and high strength and its type (vibrating and non-vibrating concrete. Since self-compacting concrete (SCC is nearly a new innovation therefore, understanding the implementation of this type of non-vibrating concrete on the ultimate unbonded tendon stress is critical. For this aim, in this paper there are presented experimental results of six continuous un-bonded post-tensioned I-beams in two groups were casted and monitored by different electrical strain gauges. In the first tested group, the beams (UPN1-12, UPN1-18, UPN1-22 were consisting of high strength normal concrete (HSNC where as in the second group (UPS1-12, UPS1-18, UPS1-22 high strength self-compacting concrete (HSSCC were tested. The variables included the type of concrete and percentage of bounded non-prestressed steel. Experimental monitored results of ultimate stress increase in unbonded tendons are compared with predicted equations of different researchers and standards. It was found that, the proposed equation is in better agreement with the test results. The results of standard error of estimate Sy/x, indicates that for two types of HSCs, the ACI 318-2011 provides better estimates than AASHTO-2010 model whereas this model provides better estimates than BS 8110-97. Keywords: Post-tensioned, Unbonded tendons, Stress increase, High strength normal and self-compacting concrete, Continuous beams

  6. Selection and Validation of Reference Genes for Quantitative Real-Time PCR Normalization Under Ethanol Stress Conditions in Oenococcus oeni SD-2a

    Directory of Open Access Journals (Sweden)

    Shuai Peng

    2018-05-01

    Full Text Available The powerful Quantitative real-time PCR (RT-qPCR was widely used to assess gene expression levels, which requires the optimal reference genes used for normalization. Oenococcus oeni (O. oeni, as the one of most important microorganisms in wine industry and the most resistant lactic acid bacteria (LAB species to ethanol, has not been investigated regarding the selection of stable reference genes for RT-qPCR normalization under ethanol stress conditions. In this study, nine candidate reference genes (proC, dnaG, rpoA, ldhD, ddlA, rrs, gyrA, gyrB, and dpoIII were analyzed to determine the most stable reference genes for RT-qPCR in O. oeni SD-2a under different ethanol stress conditions (8, 12, and 16% (v/v ethanol. The transcript stabilities of these genes were evaluated using the algorithms geNorm, NormFinder, and BestKeeper. The results showed that dnaG and dpoIII were selected as the best reference genes across all experimental ethanol conditions. Considering single stress experimental modes, dpoIII and dnaG would be suitable to normalize expression level for 8% ethanol shock treatment, while the combination of gyrA, gyrB, and rrs would be suitable for 12% ethanol shock treatment. proC and gyrB revealed the most stable expression in 16% ethanol shock treatment. This study selected and validated for the first time the reference genes for RT-qPCR normalization in O. oeni SD-2a under ethanol stress conditions.

  7. Performance, fatigue and stress in open-plan offices: The effects of noise and restoration on hearing impaired and normal hearing individuals

    Directory of Open Access Journals (Sweden)

    Helena Jahncke

    2012-01-01

    Full Text Available Hearing impaired and normal hearing individuals were compared in two within-participant office noise conditions (high noise: 60 L Aeq and low noise: 30 L Aeq . Performance, subjective fatigue, and physiological stress were tested during working on a simulated open-plan office. We also tested two between-participants restoration conditions following the work period with high noise (nature movie or continued office noise. Participants with a hearing impairment (N = 20 were matched with normal hearing participants (N = 18 and undertook one practice session and two counterbalanced experimental sessions. In each experimental session they worked for two hours with basic memory and attention tasks. We also measured physiological stress indicators (cortisol and catecholamines and self-reports of mood and fatigue. The hearing impaired participants were more affected by high noise than the normal hearing participants, as shown by impaired performance for tasks that involve recall of semantic information. The hearing impaired participants were also more fatigued by high noise exposure than participants with normal hearing, and they tended to have higher stress hormone levels during the high noise compared to the low noise condition. Restoration with a movie increased performance and motivation for the normal hearing participants, while rest with continued noise did not. For the hearing impaired participants, continued noise during rest increased motivation and performance, while the movie did not. In summary, the impact of noise and restorative conditions varied with the hearing characteristics of the participants. The small sample size does however encourage caution when interpreting the results.

  8. Stress.

    Science.gov (United States)

    Chambers, David W

    2008-01-01

    We all experience stress as a regular, and sometimes damaging and sometimes useful, part of our daily lives. In our normal ups and downs, we have our share of exhaustion, despondency, and outrage--matched with their corresponding positive moods. But burnout and workaholism are different. They are chronic, dysfunctional, self-reinforcing, life-shortening habits. Dentists, nurses, teachers, ministers, social workers, and entertainers are especially susceptible to burnout; not because they are hard-working professionals (they tend to be), but because they are caring perfectionists who share control for the success of what they do with others and perform under the scrutiny of their colleagues (they tend to). Workaholics are also trapped in self-sealing cycles, but the elements are ever-receding visions of control and using constant activity as a barrier against facing reality. This essay explores the symptoms, mechanisms, causes, and successful coping strategies for burnout and workaholism. It also takes a look at the general stress response on the physiological level and at some of the damage American society inflicts on itself.

  9. Nitric oxide is involved in light-specific responses of tomato during germination under normal and osmotic stress conditions.

    Science.gov (United States)

    Piterková, Jana; Luhová, Lenka; Hofman, Jakub; Turecková, Veronika; Novák, Ondrej; Petrivalsky, Marek; Fellner, Martin

    2012-09-01

    Nitric oxide (NO) is involved in the signalling and regulation of plant growth and development and responses to biotic and abiotic stresses. The photoperiod-sensitive mutant 7B-1 in tomato (Solanum lycopersicum) showing abscisic acid (ABA) overproduction and blue light (BL)-specific tolerance to osmotic stress represents a valuable model to study the interaction between light, hormones and stress signalling. The role of NO as a regulator of seed germination and ABA-dependent responses to osmotic stress was explored in wild-type and 7B-1 tomato under white light (WL) and BL. Germination data were obtained from the incubation of seeds on germinating media of different composition. Histochemical analysis of NO production in germinating seeds was performed by fluorescence microscopy using a cell-permeable NO probe, and endogenous ABA was analysed by mass spectrometry. The NO donor S-nitrosoglutathione stimulated seed germination, whereas the NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) had an inhibitory effect. Under WL in both genotypes, PTIO strongly suppressed germination stimulated by fluridone, an ABA inhibitor. The stimulatory effect of the NO donor was also observed under osmotic stress for 7B-1 seeds under WL and BL. Seed germination inhibited by osmotic stress was restored by fluridone under WL, but less so under BL, in both genotypes. This effect of fluridone was further modulated by the NO donor and NO scavenger, but only to a minor extent. Fluorescence microscopy using the cell-permeable NO probe DAF-FM DA (4-amino-5-methylamino-2',7'-difluorofluorescein diacetate) revealed a higher level of NO in stressed 7B-1 compared with wild-type seeds. As well as defective BL signalling, the differential NO-dependent responses of the 7B-1 mutant are probably associated with its high endogenous ABA concentration and related impact on hormonal cross-talk in germinating seeds. These data confirm that light-controlled seed germination and

  10. Stress Management

    Science.gov (United States)

    Healthy Lifestyle Stress management By Mayo Clinic Staff Stress basics Stress is a normal psychological and physical reaction to the demands of life. ... some people's alarm systems rarely shut off. Stress management gives you a range of tools to reset ...

  11. Notifiable events in systems for fission of nuclear fuels - nuclear power plants and research reactors with maximum output exceeding 50 kW of thermal normal rating - in the Federal Republic of Germany. Quarterly report, 2nd quarter of 1996

    International Nuclear Information System (INIS)

    1996-01-01

    There were 32 notifiable events in nuclear power plants in Germany in the second quarter of 1996. The report lists and characterises all the 32 events notified in the reporting period. The events did not involve any radioactivity release exceeding the maximum permissible limits during this period, so that there were no radiation hazards to the population or the environment. One event was classified at level 1 of the INES event scale (Anomaly). Research reactor operators in Germany reported 5 notifiable events in the reporting period. The report lists and characterises these events. These events did not involve any radioactivity release exceeding the maximum permissible limits during this period, so that there were no radiation hazards to the population or the environment. All events notified were classified into the lowest categories of safety significance of the official event scales (N, or below scale). (orig./DG) [de

  12. Impact of physical activity on energy balance, food intake and choice in normal weight and obese children in the setting of acute social stress: a randomized controlled trial.

    Science.gov (United States)

    Horsch, Antje; Wobmann, Marion; Kriemler, Susi; Munsch, Simone; Borloz, Sylvie; Balz, Alexandra; Marques-Vidal, Pedro; Borghini, Ayala; Puder, Jardena J

    2015-02-19

    Psychological stress negatively influences food intake and food choices, thereby contributing to the development of childhood obesity. Physical activity can also moderate eating behavior and influence calorie intake. However, it is unknown if acute physical activity influences food intake and overall energy balance after acute stress exposure in children. We therefore investigated the impact of acute physical activity on overall energy balance (food intake minus energy expenditure), food intake, and choice in the setting of acute social stress in normal weight (NW) and overweight/obese (OW/OB) children as well as the impact of psychological risk factors. After receiving written consent from their parents, 26 NW (BMI foods (6 sweet/6 salty; each of low/high caloric density). Energy balance, food intake/choice and obesity-related psychological risk factors were assessed. Lower overall energy balance (p = 0.019) and a decreased choice of low density salty foods (p foods (104 kcal (34 to 173), p = 0.004) following stress. They scored higher on impulsive behavior (p = 0.005), restrained eating (p stress-induced food intake/choice. Positive parenting tended to be related to lower intake of sweet high density food (-132 kcal, -277 to 2, p = 0.054). In the setting of stress, acute moderate physical activity can address energy balance in children, a benefit which is especially pronounced in the OW/OB. Positive parenting may act as a protective factor preventing stress-induced eating of comfort food. clinicaltrials.gov NCT01693926 The study was a pilot study of a project funded by the Swiss National Science Foundation (CRSII3_147673).

  13. Gradual training of alpacas to the confinement of metabolism pens reduces stress when normal excretion behavior is accommodated.

    Science.gov (United States)

    Lund, Kirrin E; Maloney, Shane K; Milton, John T B; Blache, Dominique

    2012-01-01

    Confinement in metabolism pens may provoke a stress response in alpacas that will reduce the welfare of the animal and jeopardize the validity of scientific results obtained in such pens. In this study, we tested a protocol designed to successfully train alpacas to be held in a specially designed metabolism pen so that the animals' confinement would not jeopardize their welfare. We hypothesized that the alpacas would show fewer behaviors associated with a response to stress as training gradually progressed, and that they would adapt to being in the confinement of the metabolism pen. The training protocol was successful at introducing alpacas to the metabolism pens, and it did reduce the incidence of behavioral responses to stress as the training progressed. The success of the training protocol may be attributed to the progressive nature of the training, the tailoring of the protocol to suit alpacas, and the use of positive reinforcement. This study demonstrated that both animal welfare and the validity of the scientific outcomes could be maximized by the gradual training of experimental animals, thereby minimizing the stress imposed on the animals during experimental procedures.

  14. Initial and delayed circulatory responses to orthostatic stress in normal humans and in subjects with orthostatic intolerance

    NARCIS (Netherlands)

    Wieling, W.; Shepherd, J. T.

    1992-01-01

    Gravitational stresses, which are common daily event for humans, result in a diminution in central blood volume, due to displacement of blood to the lower parts of the body. They demand complex adjustments in the cardiovascular system to offset the decrease in cardiac filling pressure. Such changes

  15. Approximate maximum parsimony and ancestral maximum likelihood.

    Science.gov (United States)

    Alon, Noga; Chor, Benny; Pardi, Fabio; Rapoport, Anat

    2010-01-01

    We explore the maximum parsimony (MP) and ancestral maximum likelihood (AML) criteria in phylogenetic tree reconstruction. Both problems are NP-hard, so we seek approximate solutions. We formulate the two problems as Steiner tree problems under appropriate distances. The gist of our approach is the succinct characterization of Steiner trees for a small number of leaves for the two distances. This enables the use of known Steiner tree approximation algorithms. The approach leads to a 16/9 approximation ratio for AML and asymptotically to a 1.55 approximation ratio for MP.

  16. Fkh1 and Fkh2 associate with Sir2 to control CLB2 transcription under normal and oxidative stress conditions

    Directory of Open Access Journals (Sweden)

    Christian eLinke

    2013-07-01

    Full Text Available The Forkhead box family of transcription factors is evolutionary conserved from yeast to higher eukaryotes and its members are involved in many physiological processes including metabolism, DNA repair, cell cycle, stress resistance, apoptosis and aging. In budding yeast, four Forkhead transcription factors were identified, namely Fkh1, Fkh2, Fhl1, and Hcm1, which are implicated in chromatin silencing, cell cycle regulation and stress response. These factors impinge transcriptional regulation during cell cycle progression, and histone deacetylases play an essential role in this process, e.g. the nuclear localisation of Hcm1 depends on Sir2 activity, whereas Sin3/Rpd3 silence cell cycle specific gene transcription in G2/M phase. However, a direct involvement of Sir2 in Fkh1/Fkh2-dependent regulation of target genes is at present unknown. Here, we show that Fkh1 and Fkh2 associate with Sir2 in G1 and M phase, and that Fkh1/Fkh2-mediated activation of reporter genes is antagonized by Sir2. We further report that Sir2 overexpression strongly affects cell growth in an Fkh1/Fkh2-dependent manner. In addition, Sir2 regulates the expression of the mitotic cyclin Clb2 through Fkh1/Fkh2-mediated binding to the CLB2 promoter in G1 and M phase. We finally demonstrate that Sir2 is also enriched at the CLB2 promoter under stress conditions, and that the nuclear localization of Sir2 is dependent on Fkh1 and Fkh2. Taken together, our results show a functional interplay between Fkh1/Fkh2 and Sir2 suggesting a novel mechanism of cell cycle repression. Thus, in budding yeast, not only the regulation of G2/M gene expression but also the protective response against stress could be directly coordinated by Fkh1 and Fkh2.

  17. Protective effect of Opuntia ficus-indica L. cladodes against UVA-induced oxidative stress in normal human keratinocytes.

    Science.gov (United States)

    Petruk, Ganna; Di Lorenzo, Flaviana; Imbimbo, Paola; Silipo, Alba; Bonina, Andrea; Rizza, Luisa; Piccoli, Renata; Monti, Daria Maria; Lanzetta, Rosa

    2017-12-15

    Opuntia ficus-indica L. is known for its beneficial effects on human health, but still little is known on cladodes as a potent source of antioxidants. Here, a direct, economic and safe method was set up to obtain water extracts from Opuntia ficus-indica cladodes rich in antioxidant compounds. When human keratinocytes were pre-treated with the extract before being exposed to UVA radiations, a clear protective effect against UVA-induced stress was evidenced, as indicated by the inhibition of stress-induced processes, such as free radicals production, lipid peroxidation and GSH depletion. Moreover, a clear protective effect against apoptosis in pre-treated irradiated cells was evidenced. We found that eucomic and piscidic acids were responsible for the anti-oxidative stress action of cladode extract. In conclusion, a bioactive, safe, low-cost and high value-added extract from Opuntia cladodes was obtained to be used for skin health/protection. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Reducing properties, energy efficiency and carbohydrate metabolism in hyperhydric and normal carnation shoots cultured in vitro: a hypoxia stress?

    Science.gov (United States)

    Saher, Shady; Fernández-García, Nieves; Piqueras, Abel; Hellín, Eladio; Olmos, Enrique

    2005-06-01

    Hyperhydricity is considered as a physiological disorder that can be induced by different stressing conditions. In the present work we have studied the metabolic and energetic states of hyperhydric carnation shoots. We have evaluated the hypothesis that hypoxia stress is the main factor affecting the metabolism of hyperhydric leaves. Our results indicate a low level of ATP in hyperhydric tissues, but only slight modifications in pyridine nucleotide contents. Concurrently, the glucose-6-phosphate dehydrogenase (G-6-PDH; EC 1.1.1.49) activity in hyperhydric leaves was increased but glucokinase (GK; EC 2.7.1.2) activity was unchanged. We have observed that the metabolism of pyruvate was altered in hyperhydric tissues by the induction of pyruvate synthesis via NADP-dependent malic enzyme (EC 1.1.1.40). The enzymes of the fermentative metabolism pyruvate decarboxylase (PDC; EC 4.1.1.1) and alcohol dehydrogenase (ADH; EC 1.1.1.1) were highly increased in hyperhydric leaves. Sucrose metabolism was modified in hyperhydric leaves with a high increase in the activity of both synthesis and catabolic enzymes. The analysis of the sucrose, glucose and fructose contents indicated that all of these sugars were accumulated in hyperhydric leaves. However, the pinitol content was drastically decreased in hyperhydric leaves. We consider that these results suggest that hyperhydric leaves of carnation have adapted to hypoxia stress conditions by the induction of the oxidative pentose phosphate and fermentative pathways.

  19. Maximum permissible dose

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    This chapter presents a historic overview of the establishment of radiation guidelines by various national and international agencies. The use of maximum permissible dose and maximum permissible body burden limits to derive working standards is discussed

  20. Cigarette smoke induces endoplasmic reticulum stress and the unfolded protein response in normal and malignant human lung cells

    Directory of Open Access Journals (Sweden)

    Yang Jin

    2008-08-01

    Full Text Available Abstract Background Although lung cancer is among the few malignancies for which we know the primary etiological agent (i.e., cigarette smoke, a precise understanding of the temporal sequence of events that drive tumor progression remains elusive. In addition to finding that cigarette smoke (CS impacts the functioning of key pathways with significant roles in redox homeostasis, xenobiotic detoxification, cell cycle control, and endoplasmic reticulum (ER functioning, our data highlighted a defensive role for the unfolded protein response (UPR program. The UPR promotes cell survival by reducing the accumulation of aberrantly folded proteins through translation arrest, production of chaperone proteins, and increased degradation. Importance of the UPR in maintaining tissue health is evidenced by the fact that a chronic increase in defective protein structures plays a pathogenic role in diabetes, cardiovascular disease, Alzheimer's and Parkinson's syndromes, and cancer. Methods Gene and protein expression changes in CS exposed human cell cultures were monitored by high-density microarrays and Western blot analysis. Tissue arrays containing samples from 110 lung cancers were probed with antibodies to proteins of interest using immunohistochemistry. Results We show that: 1 CS induces ER stress and activates components of the UPR; 2 reactive species in CS that promote oxidative stress are primarily responsible for UPR activation; 3 CS exposure results in increased expression of several genes with significant roles in attenuating oxidative stress; and 4 several major UPR regulators are increased either in expression (i.e., BiP and eIF2α or phosphorylation (i.e., phospho-eIF2α in a majority of human lung cancers. Conclusion These data indicate that chronic ER stress and recruitment of one or more UPR effector arms upon exposure to CS may play a pivotal role in the etiology or progression of lung cancers, and that phospho-eIF2α and BiP may have

  1. Both near ultraviolet radiation and the oxidizing agent hydrogen peroxide induce a 32-kDa stress protein in normal human skin fibroblasts

    International Nuclear Information System (INIS)

    Keyse, S.M.; Tyrrell, R.M.

    1987-01-01

    We have analyzed the pattern of protein synthesis in solar near ultraviolet (334 nm, 365 nm) and near visible (405 nm) irradiated normal human skin fibroblasts. Two hours after irradiation we find that one major stress protein of approximately 32 kDa is induced in irradiated cells. This protein is not induced by ultraviolet radiation at wavelengths shorter than 334 nm and is not inducible by heat shock treatment of these cells. Although sodium arsenite, diamide, and menadione all induced a 32-kDa protein, they also induced the major heat shock proteins. In contrast, the oxidizing agent, hydrogen peroxide, induced the low molecular weight stress protein without causing induction of the major heat shock proteins. A comparison of the 32-kDa proteins induced by sodium arsenite, H 2 O 2 , and solar near ultraviolet radiation using chemical peptide mapping shows that they are closely related. These results imply that the pathways for induction of the heat shock response and the 32-kDa protein are not identical and suggest that, at least in the case of radiation and treatment with H 2 O 2 , the 32-kDa protein might be induced in response to cellular oxidative stress. This conclusion is supported by the observation that depletion of endogenous cellular glutathione prior to solar near ultraviolet irradiation lowers the fluence threshold for induction of the 32-kDa stress protein

  2. Effect of second to first normal stress difference ratio at the die exit on neck-in phenomenon in polymeric flat film production

    Science.gov (United States)

    Barborik, Tomas; Zatloukal, Martin

    2017-05-01

    In this study, viscoelastic modeling of the extrusion film casting process, based on the lD membrane model and modified Leonov constitutive equation, was conducted and the effect of the viscoelastic stress state at the die exit (captured here via second to first normal stress difference ratio) on the unwanted neck-in phenomenon has been analyzed for wide range of Deborah numbers and materials having different level of uniaxial and planar extensional strain hardening. Relevant experimental data for LDPE and theoretical predictions based on multimode eXtended Pom-Pom model acquired from the open literature were used for the validation purposes. It was found that firstly, the predicting capabilities of both constitutive equations for given material and processing conditions are comparable even if the single mode modified Leonov model was used and secondly, the agreement between theoretical and experimental data on neck-in is fairly good. Results of the theoretical study revealed that the viscoelastic stress state at the die exit (i.e. -N2/N1 ratio) increases the level of neck-in if uniaxial extensional strain hardening, planar to uniaxial extensional viscosity ratio and Deborah number increases. It has also been revealed that there exists threshold value for Deborah number and extensional strain hardening below which the neck-in becomes independent on the die exit stress state.

  3. Stress

    Science.gov (United States)

    ... taking care of an aging parent. With mental stress, the body pumps out hormones to no avail. Neither fighting ... with type 1 diabetes. This difference makes sense. Stress blocks the body from releasing insulin in people with type 2 ...

  4. Identifying optimal reference genes for the normalization of microRNA expression in cucumber under viral stress

    Science.gov (United States)

    Liang, Chaoqiong; Hao, Jianjun; Meng, Yan; Luo, Laixin; Li, Jianqiang

    2018-01-01

    Cucumber green mottle mosaic virus (CGMMV) is an economically important pathogen and causes significant reduction of both yield and quality of cucumber (Cucumis sativus). Currently, there were no satisfied strategies for controlling the disease. A better understanding of microRNA (miRNA) expression related to the regulation of plant-virus interactions and virus resistance would be of great assistance when developing control strategies for CGMMV. However, accurate expression analysis is highly dependent on robust and reliable reference gene used as an internal control for normalization of miRNA expression. Most commonly used reference genes involved in CGMMV-infected cucumber are not universally expressed depending on tissue types and stages of plant development. It is therefore crucial to identify suitable reference genes in investigating the role of miRNA expression. In this study, seven reference genes, including Actin, Tubulin, EF-1α, 18S rRNA, Ubiquitin, GAPDH and Cyclophilin, were evaluated for the most accurate results in analyses using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Gene expression was assayed on cucumber leaves, stems and roots that were collected at different days post inoculation with CGMMV. The expression data were analyzed using algorithms including delta-Ct, geNorm, NormFinder, and BestKeeper as well as the comparative tool RefFinder. The reference genes were subsequently validated using miR159. The results showed that EF-1α and GAPDH were the most reliable reference genes for normalizing miRNA expression in leaf, root and stem samples, while Ubiquitin and EF-1α were the most suitable combination overall. PMID:29543906

  5. Normal LVEF measurements are significantly higher in females asassessed by post-stress resting Tc-99m sestamibi gated myocardial perfusion SPECT

    International Nuclear Information System (INIS)

    Kim, Jong Ho; Shin, Eak Kyun

    1999-01-01

    Volume-LVEF relationship is one of the most important factors of automatic EF quantification algorithm from gated myocardial perfusion SPECT(gMPS) (Germano et al. JNM, 1995). Gender difference whereby normal LVEF measurements are higher in females assessed by gMPS (Yao et al. JNM 1997). To validate true physiologic value of LVEF vs sampling or measured error, various parameters were evaluated statistically in both gender and age matched 200 subjects (mean age= 58.41±15.01) with normal LVEF more than 50%, and a low likelihood of coronary artery disease. Correlation between LVEDVi(ml/m2) and LVEF was highly significant (r=-0.62, p<0.0001) with similar correlations noted in both male (r=-0.45, p<0.0001) and female (r=-0.67, p<0.0001) subgroups. By multivariate analysis, LV volume and stroke volume was the most significant factor influencing LVEF in male and female, respectively. In conclusion, there is a significant negative correlation between LV volume and LVEF as measured by Tc-99m gated SPECT. Higher normal LVEF value should be applied to females as assessed by post-stress resting Tc-99m Sestamibi gated myocardial perfusion SPECT

  6. Determination of PVB interlayer’s shear modulus and its effect on normal stress distribution in laminated glass panels

    Science.gov (United States)

    Hána, T.; Eliášová, M.; Machalická, K.; Vokáč, M.

    2017-10-01

    Noticing the current architecture, there are many examples of glass bearing members such as beams, panes, ribs stairs or even columns. Most of these elements are made of laminated glass from panes bonded by polymer interlayer so the task of transferring shear forces between the glass panes needs to be investigated due to the lack of knowledge. This transfer depends on stiffness of polymer material, which is affected by temperature and load duration. It is essential to catch the safe side with limit cases when designing these members if the exact material behaviour is not specified. There are lots of interlayers for structural laminated glass applications available on a market. Most of them exhibit different properties, which need to be experimentally verified. This paper is focused on tangent shear modulus of PVB (polyvinyl-buthyral) interlayer and its effect on the stress distribution in glass panes when loaded. This distribution may be determined experimentally or numerically, respectively. This enables to design structural laminated glass members more effectively regarding price and safety. Furthermore, this is the way, how to extend the use of laminated glass in architectural design.

  7. Nitric oxide signals are interlinked with calcium signals in normal pancreatic stellate cells upon oxidative stress and inflammation.

    Science.gov (United States)

    Jakubowska, Monika A; Ferdek, Pawel E; Gerasimenko, Oleg V; Gerasimenko, Julia V; Petersen, Ole H

    2016-08-01

    The mammalian diffuse stellate cell system comprises retinoid-storing cells capable of remarkable transformations from a quiescent to an activated myofibroblast-like phenotype. Activated pancreatic stellate cells (PSCs) attract attention owing to the pivotal role they play in development of tissue fibrosis in chronic pancreatitis and pancreatic cancer. However, little is known about the actual role of PSCs in the normal pancreas. These enigmatic cells have recently been shown to respond to physiological stimuli in a manner that is markedly different from their neighbouring pancreatic acinar cells (PACs). Here, we demonstrate the capacity of PSCs to generate nitric oxide (NO), a free radical messenger mediating, for example, inflammation and vasodilatation. We show that production of cytosolic NO in PSCs is unambiguously related to cytosolic Ca(2+) signals. Only stimuli that evoke Ca(2+) signals in the PSCs elicit consequent NO generation. We provide fresh evidence for the striking difference between signalling pathways in PSCs and adjacent PACs, because PSCs, in contrast to PACs, generate substantial Ca(2+)-mediated and NOS-dependent NO signals. We also show that inhibition of NO generation protects both PSCs and PACs from necrosis. Our results highlight the interplay between Ca(2+) and NO signalling pathways in cell-cell communication, and also identify a potential therapeutic target for anti-inflammatory therapies. © 2016 The Authors.

  8. The Effect of Shock Stress and Field Strength on Shock-Induced Depoling of Normally Poled PZT 95/5

    International Nuclear Information System (INIS)

    CHHABILDAS, LALIT C.; FURNISH, MICHAEL D.; MONTGOMERY, STEPHEN T.; SETCHELL, ROBERT E.

    1999-01-01

    Shock-induced depoling of the ferroelectric ceramic PZT 95/5 is utilized in a number of pulsed power devices. Several experimental and theoretical efforts are in progress in order to improve numerical simulations of these devices. In this study we have examined the shock response of normally poled PZT 95/5 under uniaxial strain conditions. On each experiment the current produced in an external circuit and the transmitted waveform at a window interface were recorded. The peak electrical field generated within the PZT sample was varied through the choice of external circuit resistance. Shock pressures were varied from 0.6 to 4.6 GPa, and peak electrical fields were varied from 0.2 to 37 kV/cm. For a 2.4 GPa shock and the lowest peak field, a nearly constant current governed simply by the remanent polarization and the shock velocity was recorded. Both decreasing the shock pressure and increasing the electrical field resulted in reduced current generation, indicating a retardation of the depoling kinetics

  9. Common chromosomal fragile sites (CFS) may be involved in normal and traumatic cognitive stress memory consolidation and altered nervous system immunity.

    Science.gov (United States)

    Gericke, G S

    2010-05-01

    Previous reports of specific patterns of increased fragility at common chromosomal fragile sites (CFS) found in association with certain neurobehavioural disorders did not attract attention at the time due to a shift towards molecular approaches to delineate neuropsychiatric disorder candidate genes. Links with miRNA, altered methylation and the origin of copy number variation indicate that CFS region characteristics may be part of chromatinomic mechanisms that are increasingly linked with neuroplasticity and memory. Current reports of large-scale double-stranded DNA breaks in differentiating neurons and evidence of ongoing DNA demethylation of specific gene promoters in adult hippocampus may shed new light on the dynamic epigenetic changes that are increasingly appreciated as contributing to long-term memory consolidation. The expression of immune recombination activating genes in key stress-induced memory regions suggests the adoption by the brain of this ancient pattern recognition and memory system to establish a structural basis for long-term memory through controlled chromosomal breakage at highly specific genomic regions. It is furthermore considered that these mechanisms for management of epigenetic information related to stress memory could be linked, in some instances, with the transfer of the somatically acquired information to the germline. Here, rearranged sequences can be subjected to further selection and possible eventual retrotranscription to become part of the more stable coding machinery if proven to be crucial for survival and reproduction. While linkage of cognitive memory with stress and fear circuitry and memory establishment through structural DNA modification is proposed as a normal process, inappropriate activation of immune-like genomic rearrangement processes through traumatic stress memory may have the potential to lead to undesirable activation of neuro-inflammatory processes. These theories could have a significant impact on the

  10. Fatigue as Presenting Symptom and a High Burden of Premature Ventricular Contractions Are Independently Associated With Increased Ventricular Wall Stress in Patients With Normal Left Ventricular Function.

    Science.gov (United States)

    van Huls van Taxis, Carine F B; Piers, Sebastiaan R D; de Riva Silva, Marta; Dekkers, Olaf M; Pijnappels, Daniël A; Schalij, Martin J; Wijnmaalen, Adrianus P; Zeppenfeld, Katja

    2015-12-01

    High idiopathic premature ventricular contractions (PVC) burden has been associated with PVC-induced cardiomyopathy. Patients may be symptomatic before left ventricular (LV) dysfunction develops. N-terminal pro-B-type natriuretic peptide (NT-proBNP) and circumferential end-systolic wall stress (cESS) on echocardiography are markers for increased ventricular wall stress. This study aimed to evaluate the relation between presenting symptoms, PVC burden, and increased ventricular wall stress in patients with frequent PVCs and preserved LV function. Eighty-three patients (41 men; 49±15 years) with idiopathic PVCs and normal LV function referred for PVC ablation were included. Type of symptoms (palpitations, fatigue, and [near-]syncope), PVC burden on 24-hour Holter, NT-proBNP levels, and cESS on echocardiography were assessed before and 3 months after ablation. Sustained successful ablation was defined as ≥80% PVC burden reduction during follow-up. Patients were symptomatic for 24 months (Q1-Q3, 16-60); 73% reported palpitations, 47% fatigue, and 30% (near-)syncope. Baseline PVC burden was 23±13%, median NT-proBNP 92 pg/mL (Q1-Q3 50-156), and cESS 143±35 kdyne/cm(2). Fatigue was associated with higher baseline NT-proBNP and cESS (PFatigue was independently associated with a significantly larger reduction in NT-proBNP. In patients with nonsuccessful ablation, NT-proBNP and cESS remained unchanged. In patients with frequent PVCs and preserved LV function, fatigue was associated with higher baseline NT-proBNP and cESS, and with a significantly larger reduction in NT-proBNP after sustained successful ablation. These findings support a link between fatigue and PVC-induced increased ventricular wall stress, despite preserved LV function. © 2015 American Heart Association, Inc.

  11. Effects of dietary chlorogenic acid on growth performance, antioxidant capacity of white shrimp Litopenaeus vannamei under normal condition and combined stress of low-salinity and nitrite.

    Science.gov (United States)

    Wang, Yun; Li, Zheng; Li, Jian; Duan, Ya-Fei; Niu, Jin; Wang, Jun; Huang, Zhong; Lin, Hei-Zhao

    2015-04-01

    An eight-week feeding trial followed by an acute combined stress test of low-salinity and nitrite were performed to evaluate effects of chlorogenic acid (CGA) on growth performance and antioxidant capacity of white shrimp Litopenaeus vannamei. Shrimp were randomly allocated in 12 tanks (30 shrimp per tank) and triplicate tanks were fed with a control diet or diets containing different levels of CGA (100, 200 and 400 mg kg(-1) feed) as treatment groups. Growth performance including weight gain (WG), biomass gain (BG), feed conversion ratio (FCR), and feed intake were determined after feeding for 56 days. Antioxidant capacity were evaluated by determining the activity of total antioxidant status (TAS), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) as well as the gene expression of GSH-Px and CAT in the hepatopancreas of shrimp at the end of feeding trial and again at the end of the combined stress test. The results indicated that supplemention of CGA had no significant effects on the growth performance and the activities of TAS, SOD, GSH-Px and CAT in hepatopancreas of shrimp cultured under normal conditions for 56 days. However, compared with the control group, CGA (200, 400 mg kg(-1) feed) significantly improved the resistance of L. vannamei against the combined stress of low-salinity and nitrite, as indicated by the significant (P shrimp treated with CGA in the combined tress test. Our findings suggested that CGA possessed dual-modulatory effects on antioxidant capacity of L. vannamei and could be a potential feed additive that can enhance shrimp resistance against environmental stresses. The recommended application dosage is 200 mg kg(-1) and further studies are needed to clarify the action model of CGA efficiency. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Future cardiac events in patients with ischemic ECG changes during adenosine infusion as a myocardial stress agent and normal cardiac scan.

    Science.gov (United States)

    Amer, Hamid; Niaz, Khalid; Hatazawa, Jun; Gasmelseed, Ahmed; Samiri, Hussain Al; Al Othman, Maram; Hammad, Mai Al

    2017-11-01

    We sought to determine the prognostic importance of adenosine-induced ischemic ECG changes in patients with normal single-photon emission computed tomography myocardial perfusion images (MPI). We carried out a retrospective analysis of 765 patients undergoing adenosine MPI between January 2013 and January 2015. Patients with baseline ECG abnormalities and/or abnormal scan were excluded. Overall, 67 (8.7%) patients had ischemic ECG changes during adenosine infusion in the form of ST depression of 1 mm or more. Of these, 29 [43% (3.8% of all patients)] had normal MPI (positive ECG group). An age-matched and sex-matched group of 108 patients with normal MPI without ECG changes served as control participants (negative ECG group). During a mean follow-up duration of 33.3±6.1 months, patients in the positive ECG group did not have significantly more adverse cardiac events than those in the negative ECG group. One (0.9%) patient in the negative ECG group had a nonfatal myocardial infarction (0.7% annual event rate after a negative MPI). Also in this group, two (1.8%) patients admitted with a diagnosis of CAD where they have been ruled out by angiography. A fourth case in this, in the negative ECG group, was admitted because of heart failure that proved to be secondary to a pulmonary cause and not CAD. A case only in the positive ECG group was admitted as a CAD that was ruled out by coronary angiography. Patients with normal myocardial perfusion scintigraphy in whom ST-segment depression develops during adenosine stress test appear to have no increased risk for future cardiac events compared with similar patients without ECG evidence of ischemia.

  13. Maximum Acceleration Recording Circuit

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

  14. Effect of stress, strain and optical properties in vacuum and normal annealed ZnO thin films using RF magnetron sputtering

    Science.gov (United States)

    Kumar, B. Santhosh; Purvaja, K.; Harinee, N.; Venkateswaran, C.

    2018-05-01

    Zinc oxide thin films have been deposited on quartz substrate using RF magnetron sputtering. The deposited films were subjected to different annealing atmosphere at a fixed temperature of 500 °C for 5h. The X-ray diffraction (XRD) patterns reveals the shift in the peak of both normal annealed and vacuum annealed thin films when compared to as-deposited ZnO film. The crystallite size, intrinsic stress and other parameters were calculated from XRD data. The surface morphology of the obtained films were studied using Atomic force microscopy (AFM). From Uv-Visible spectroscopy, the peak at 374 nm of all the films is characteristics of ZnO. The structural, thermal stability and optical properties of the annealed ZnO films are discussed in detail.

  15. Characteristics of six small heat shock protein genes from Bactrocera dorsalis: Diverse expression under conditions of thermal stress and normal growth.

    Science.gov (United States)

    Dou, Wei; Tian, Yi; Liu, Hong; Shi, Yan; Smagghe, Guy; Wang, Jin-Jun

    2017-11-01

    To explore the functions of small heat shock proteins (sHsps) in relation to thermal stress and development in Bactrocera dorsalis (Hendel), one of the most economically important pest species attacking a wide range of fruits and vegetables, six full-length cDNAs of sHsp genes (BdHsp17.7, 18.4, 20.4, 20.6, 21.6 and 23.8) were cloned, and the expression patterns in different developmental stages and tissues, as well as in response to both thermal and 20-hydroxyecdysone (20E) exposures, were examined using real time quantitative PCR. The open reading frames (ORFs) of six sHsps are 453, 489, 537, 543, 567 and 630bp in length, encoding proteins with molecular weights of 17.7, 18.4, 20.4, 20.6, 21.6 and 23.8kDa, respectively. BdHsp18.4 and BdHsp20.4 maintained lower expression levels in both eggs and larvae, whereas remarkably up-regulated after the larval-pupal transformation, suggesting that these two sHsps may be involved in metamorphosis. Significant tissue specificity exists among sHsps: the highest expression of BdHsp20.6 and BdHsp23.8 in the Malpighian tubules and ovary, respectively, versus a peak in the fat body for others. BdHsp20.4 and BdHsp20.6 were significantly up-regulated by thermal stress. In contrast, BdHsp18.4 and BdHsp23.8 reacted only to heat stress. BdHsp17.7 and BdHsp21.6 were insensitive to both heat and cold stresses. The degree of sHsps response depends on intensity of 20E treatment, i.e., dose and time. These results strongly suggest functional differentiation within the sHsp subfamily in B. dorsalis. The physiological function of sHsp members under thermal stress and normal growth remains the subjects of further investigation. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Maximum Quantum Entropy Method

    OpenAIRE

    Sim, Jae-Hoon; Han, Myung Joon

    2018-01-01

    Maximum entropy method for analytic continuation is extended by introducing quantum relative entropy. This new method is formulated in terms of matrix-valued functions and therefore invariant under arbitrary unitary transformation of input matrix. As a result, the continuation of off-diagonal elements becomes straightforward. Without introducing any further ambiguity, the Bayesian probabilistic interpretation is maintained just as in the conventional maximum entropy method. The applications o...

  17. Maximum power demand cost

    International Nuclear Information System (INIS)

    Biondi, L.

    1998-01-01

    The charging for a service is a supplier's remuneration for the expenses incurred in providing it. There are currently two charges for electricity: consumption and maximum demand. While no problem arises about the former, the issue is more complicated for the latter and the analysis in this article tends to show that the annual charge for maximum demand arbitrarily discriminates among consumer groups, to the disadvantage of some [it

  18. Characterization of six small HSP genes from Chironomus riparius (Diptera, Chironomidae): Differential expression under conditions of normal growth and heat-induced stress.

    Science.gov (United States)

    Martín-Folgar, Raquel; de la Fuente, Mercedes; Morcillo, Gloria; Martínez-Guitarte, José-Luis

    2015-10-01

    Small heat shock proteins (sHSPs) comprise the most numerous, structurally diverse, and functionally uncharacterized family of heat shock proteins. Several Hsp genes (Hsp 90, 70, 40, and 27) from the insect Chironomus riparius are widely used in aquatic toxicology as biomarkers for environmental toxins. Here, we conducted a comparative study and characterized secondary structure of the six newly identified sHsp genes Hsp17, Hsp21, Hsp22, Hsp23, Hsp24, and Hsp34. A characteristic α-crystallin domain is predicted in all the new proteins. Phylogenetic analysis suggests a strong relation to other sHSPs from insects and interesting evidence regarding evolutionary origin and duplication events. Comparative analysis of transcription profiles for Hsp27, Hsp70, and the six newly identified genes revealed that Hsp17, Hsp21, and Hsp22 are constitutively expressed under normal conditions, while under two different heat shock conditions these genes are either not activated or are even repressed (Hsp22). In contrast, Hsp23, Hsp24, and Hsp34 are significantly activated along with Hsp27 and Hsp70 during heat stress. These results strongly suggest functional differentiation within the small HSP subfamily and provide new data to help understand the coping mechanisms induced by stressful environmental stimuli. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Histone variant H2A.Z antagonizes the positive effect of the transcriptional activator CPC1 to regulate catalase-3 expression under normal and oxidative stress conditions.

    Science.gov (United States)

    Dong, Qing; Wang, Yajun; Qi, Shaohua; Gai, Kexin; He, Qun; Wang, Ying

    2018-05-05

    In eukaryotes, deposition of the histone variant H2A.Z into nucleosomes through the chromatin remodeling complex, SWR1, is a crucial step in modulating gene transcription. Recently, H2A.Z has been shown to control the expression of responsive genes, but the underlying mechanism of how H2A.Z responds to physiological stimuli is not well understood. Here, we reveal that, in Neurospora crassa, H2A.Z is a negative regulator of catalase-3 gene, which is responsible for resistance to oxidative stress. H2A.Z represses cat-3 gene expression through direct incorporation at cat-3 locus in a SWR1 complex dependent pathway. Notably, loss of H2A.Z or SWR1 subunits leads to increased binding of a transcription factor, CPC1, at cat-3 locus. Additionally, introduction of plasmids containing gene encoding H2A.Z or SWR1 complex subunits into wild-type strains decreased CAT-3 expression, indicating that H2A.Z counteracts the positive effect of CPC1 to achieve low level cat-3 expression under non-inductive condition. Furthermore, upon oxidative stress, H2A.Z is rapidly evicted from cat-3 locus for the recruitment of CPC1, resulting in robust and full cat-3 gene expression in response to external stimuli. Collectively, this study strongly demonstrates that H2A.Z antagonizes the function of transcription factor to regulate responsive gene transcription under normal conditions and to poise for gene full activation under oxidative stress. Copyright © 2018. Published by Elsevier Inc.

  20. Stress

    DEFF Research Database (Denmark)

    Keller, Hanne Dauer

    2015-01-01

    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  1. Stress !!!

    OpenAIRE

    Fledderus, M.

    2012-01-01

    Twee op de vijf UT-studenten hebben last van ernstige studiestress, zo erg zelfs dat het ze in hun privéleven belemmert. Die cijfers komen overeen met het landelijk beeld van stress onder studenten. Samen met 14 andere universiteits- en hogeschoolbladen enquêteerde UT Nieuws bijna 5500 studenten. Opvallend is dat mannelijke studenten uit Twente zich veel minder druk lijken te maken over hun studie. Onder vrouwen ligt de stress juist erg hoog ten opzichte van het landelijk gemiddelde.

  2. Maximum likely scale estimation

    DEFF Research Database (Denmark)

    Loog, Marco; Pedersen, Kim Steenstrup; Markussen, Bo

    2005-01-01

    A maximum likelihood local scale estimation principle is presented. An actual implementation of the estimation principle uses second order moments of multiple measurements at a fixed location in the image. These measurements consist of Gaussian derivatives possibly taken at several scales and/or ...

  3. Robust Maximum Association Estimators

    NARCIS (Netherlands)

    A. Alfons (Andreas); C. Croux (Christophe); P. Filzmoser (Peter)

    2017-01-01

    textabstractThe maximum association between two multivariate variables X and Y is defined as the maximal value that a bivariate association measure between one-dimensional projections αX and αY can attain. Taking the Pearson correlation as projection index results in the first canonical correlation

  4. 13N-ammonia rest/stress PET. Folic acid improves global coronary vasoreactivity in coronary artery disease patients with normal or elevated homocysteine levels

    International Nuclear Information System (INIS)

    Graf, S.; Nikfardjam, M.; Khorsand, A.; Maurer, G.; Ofluoglu, S.; Dudczak, R.; Kletter, K.; Nekolla, S.; Huber, K.; Pirich, C.

    2006-01-01

    Aim: hyperhomocysteinaemia (Hhcy) is known to be an independent risk factor for vascular disease. Coronary flow reserve (CFR) measured by positron emission tomography (PET) is a sensitive method to monitor the effects of pharmacologic interventions in Hhcy. We assessed coronary vascular reactivity by PET in patients with coronary artery disease (CAD) dependent on their homocysteine (Hcy) levels before and under high dose folic acid supplementation therapy (FAST). Patients, methods: twelve patients with CAD underwent rest/adenosine 13 N-ammonia PET for quantification of myocardial blood flow (MBF) and CFR before and after nine weeks FAST (10 mg/day). Results: folate levels increased from 21 ± 6 to 210 ± 34 μg/l (+900%, p < 0.0001) while Hcy levels decreased from 12.1 ± 3.6 to 9.1 ± 3.1 μmol/l (-25%; p < 0.01). Global resting MBF remained nearly unchanged after FAST, while stress MBF (from 2.61 ± 0.93 to 3.25 ± 1.15 ml/g/min; p = 0.05) and CFR (from 3.00 ± 0.76 to 3.72 ± 0.93 ml/g/min; p < 0.05; +24%) significantly increased in patients with normal and elevated Hcy levels (cut off 12 μmol/l). An inverse relation was found between Hcy and CFR (R = -0.53; p = 0.08) and between Hcy and MBF at rest (R = -0.62; p < 0.05) at baseline conditions, not persisting after FAST. Conclusion: coronary vascular reactivity con be improved by FAST in patients with CAD and normal or elevated Hcy levels. FAST might lower an increased cardiovascular risk in CAD patients possibly by mechanisms that are not related to Hcy. (orig.)

  5. Maximum power point tracking

    International Nuclear Information System (INIS)

    Enslin, J.H.R.

    1990-01-01

    A well engineered renewable remote energy system, utilizing the principal of Maximum Power Point Tracking can be m ore cost effective, has a higher reliability and can improve the quality of life in remote areas. This paper reports that a high-efficient power electronic converter, for converting the output voltage of a solar panel, or wind generator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximum power point of the input source under varying input and output parameters. Maximum power point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of 15% on 3-5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply systems. The advantages at larger temperature variations and larger power rated systems are much higher. Other advantages include optimal sizing and system monitor and control

  6. Stress !!!

    NARCIS (Netherlands)

    Fledderus, M.

    2012-01-01

    Twee op de vijf UT-studenten hebben last van ernstige studiestress, zo erg zelfs dat het ze in hun privéleven belemmert. Die cijfers komen overeen met het landelijk beeld van stress onder studenten. Samen met 14 andere universiteits- en hogeschoolbladen enquêteerde UT Nieuws bijna 5500 studenten.

  7. Maximum entropy methods

    International Nuclear Information System (INIS)

    Ponman, T.J.

    1984-01-01

    For some years now two different expressions have been in use for maximum entropy image restoration and there has been some controversy over which one is appropriate for a given problem. Here two further entropies are presented and it is argued that there is no single correct algorithm. The properties of the four different methods are compared using simple 1D simulations with a view to showing how they can be used together to gain as much information as possible about the original object. (orig.)

  8. Achieving maximum baryon densities

    International Nuclear Information System (INIS)

    Gyulassy, M.

    1984-01-01

    In continuing work on nuclear stopping power in the energy range E/sub lab/ approx. 10 GeV/nucleon, calculations were made of the energy and baryon densities that could be achieved in uranium-uranium collisions. Results are shown. The energy density reached could exceed 2 GeV/fm 3 and baryon densities could reach as high as ten times normal nuclear densities

  9. The last glacial maximum

    Science.gov (United States)

    Clark, P.U.; Dyke, A.S.; Shakun, J.D.; Carlson, A.E.; Clark, J.; Wohlfarth, B.; Mitrovica, J.X.; Hostetler, S.W.; McCabe, A.M.

    2009-01-01

    We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO2. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level ???14.5 ka.

  10. Leukemic transformation of normal murine erythroid progenitors: v- and c-ErbB act through signaling pathways activated by the EpoR and c-Kit in stress erythropoiesis

    NARCIS (Netherlands)

    von Lindern, M.; Deiner, E. M.; Dolznig, H.; Parren-van Amelsvoort, M.; Hayman, M. J.; Mullner, E. W.; Beug, H.

    2001-01-01

    Primary erythroid progenitors can be expanded by the synergistic action of erythropoietin (Epo), stem cell factor (SCF) and glucocorticoids. While Epo is required for erythropoiesis in general, glucocorticoids and SCF mainly contribute to stress erythropoiesis in hypoxic mice. This ability of normal

  11. of psychological stress (ID 1598, 1601), maintenance of normal sleep (ID 1222, 1737, 2004) and reduction of menstrual discomfort (ID 1599) pursuant to Article 13(1) of Regulation (EC) No 1924/2006

    DEFF Research Database (Denmark)

    Tetens, Inge

    claims in relation to L-theanine from Camellia sinensis (L.) Kuntze (tea) and improvement of cognitive function, alleviation of psychological stress, maintenance of normal sleep and reduction of menstrual discomfort. The scientific substantiation is based on the information provided by the Member States...

  12. High self-perceived stress and many stressors, but normal diurnal cortisol rhythm, in adults with ADHD (attention-deficit/hyperactivity disorder).

    Science.gov (United States)

    Hirvikoski, Tatja; Lindholm, Torun; Nordenström, Anna; Nordström, Anna-Lena; Lajic, Svetlana

    2009-03-01

    Attention-deficit/hyperactivity disorder (ADHD) in adults is associated with significant impairment in many life activities and may thus increase the risk of chronic stress in everyday life. We compared adults with a DSM-IV ADHD diagnosis (n=28) with healthy controls (n=28) regarding subjective stress and amounts of stressors in everyday life, diurnal salivary cortisol in the everyday environment and salivary cortisol before and after cognitive stress in a laboratory setting. The association between cortisol concentrations and impulsivity was also investigated. Consistent with assumptions, individuals with ADHD reported significantly more self-perceived stress than controls, and subjective stress correlated with the amount of stressors in everyday life. The two groups were comparable with respect to overall diurnal cortisol levels and rhythm, as well as in pre- and post-stress cortisol concentrations. Post-stress cortisol (but not baseline cortisol) concentration was positively correlated with impulsivity. The group with high post-stress cortisol also reported more symptoms of depression and anxiety, as well as self-perceived stress and stressors in every-day life. The diagnosis of ADHD significantly increased the risk of belonging to the group with high post-stress cortisol levels. The results in this study warrant a focus not only on the primary diagnosis of ADHD, but also calls for a broader assessment of stressors and subjective stress in everyday life, as well as support comprising stress management and coping skills.

  13. Maximum Entropy Fundamentals

    Directory of Open Access Journals (Sweden)

    F. Topsøe

    2001-09-01

    Full Text Available Abstract: In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over

  14. Recovery of normal testicular temperature after scrotal heat stress in rams assessed by infrared thermography and its effects on seminal characteristics and testosterone blood serum concentration.

    Science.gov (United States)

    Alves, Maíra Bianchi Rodrigues; Andrade, André Furugen Cesar de; Arruda, Rubens Paes de; Batissaco, Leonardo; Florez-Rodriguez, Shirley Andrea; Oliveira, Bruna Marcele Martins de; Torres, Mariana Andrade; Lançoni, Renata; Ravagnani, Gisele Mouro; Prado Filho, Roberto Romano do; Vellone, Vinícius Silva; Losano, João Diego de Agostini; Franci, Celso Rodrigues; Nichi, Marcílio; Celeghini, Eneiva Carla Carvalho

    2016-08-01

    Reestablishment of testicular normal temperature after testicular heat stress is unknown and its effect varies widely. The aim of this study was to investigate the impact of scrotal insulation (IN) on testicular temperature and its relation to semen quality and testosterone blood serum concentration. For this, 33 rams were used; 17 submitted to IN for 72 hours (using bags involving the testes) and 16 not submitted to IN (control group). The experiment was performed between August and December 2013 in Pirassununga, Brazil (21°56″13″ South/47°28'24″ West). Seminal characteristics, testosterone blood serum concentration, rectal temperature (RT), respiratory frequency, scrotal superficies mean temperature (SSMT), and eye area mean temperature (EAMT) were analyzed 7 days before IN and 21, 35, 49, 63, and 90 days afterward. Scrotal superficies mean temperature and EAMT were measured by thermography camera FLIR T620. Testosterone was evaluated by radioimmunoassay. Analysis of variance was used to determine the main effects of treatment, time, and treatment-by-time interaction using PROC MIXED of SAS software adding command REPEAT. Pearson correlation test was used to verify correlation between SSMT, EAMT, RT, and respiratory frequency. Significant difference was considered when P ≤ 0.05. At the end of IN, SSMT was higher (P blood serum concentration was lesser in insulated rams (P = 0.03). Thus, the difference of 1.12 °C between RT and testicular temperature impacts semen quality and testosterone blood serum concentration. Moreover, this study shows that rams can recover testes temperature efficiently toward IN and that infrared thermography is an efficient tool to identify differences on SSMT. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Elastic stress transmission and transformation (ESTT) by confined liquid: A new mechanics for fracture in elastic lithosphere of the earth

    Science.gov (United States)

    Xu, Xing-Wang; Peters, Stephen; Liang, Guang-He; Zhang, Bao-Lin

    2016-01-01

    We report on a new mechanical principle, which suggests that a confined liquid in the elastic lithosphere has the potential to transmit a maximum applied compressive stress. This stress can be transmitted to the internal contacts between rock and liquid and would then be transformed into a normal compressive stress with tangential tensile stress components. During this process, both effective compressive normal stress and tensile tangential stresses arise along the liquid–rock contact. The minimum effective tensile tangential stress causes the surrounding rock to rupture. Liquid-driven fracture initiates at the point along the rock–liquid boundary where the maximum compressive stress is applied and propagates along a plane that is perpendicular to the minimum effective tensile tangential stress and also is perpendicular to the minimum principal stress.

  16. Probable maximum flood control

    International Nuclear Information System (INIS)

    DeGabriele, C.E.; Wu, C.L.

    1991-11-01

    This study proposes preliminary design concepts to protect the waste-handling facilities and all shaft and ramp entries to the underground from the probable maximum flood (PMF) in the current design configuration for the proposed Nevada Nuclear Waste Storage Investigation (NNWSI) repository protection provisions were furnished by the United States Bureau of Reclamation (USSR) or developed from USSR data. Proposed flood protection provisions include site grading, drainage channels, and diversion dikes. Figures are provided to show these proposed flood protection provisions at each area investigated. These areas are the central surface facilities (including the waste-handling building and waste treatment building), tuff ramp portal, waste ramp portal, men-and-materials shaft, emplacement exhaust shaft, and exploratory shafts facility

  17. Introduction to maximum entropy

    International Nuclear Information System (INIS)

    Sivia, D.S.

    1988-01-01

    The maximum entropy (MaxEnt) principle has been successfully used in image reconstruction in a wide variety of fields. We review the need for such methods in data analysis and show, by use of a very simple example, why MaxEnt is to be preferred over other regularizing functions. This leads to a more general interpretation of the MaxEnt method, and its use is illustrated with several different examples. Practical difficulties with non-linear problems still remain, this being highlighted by the notorious phase problem in crystallography. We conclude with an example from neutron scattering, using data from a filter difference spectrometer to contrast MaxEnt with a conventional deconvolution. 12 refs., 8 figs., 1 tab

  18. Solar maximum observatory

    International Nuclear Information System (INIS)

    Rust, D.M.

    1984-01-01

    The successful retrieval and repair of the Solar Maximum Mission (SMM) satellite by Shuttle astronauts in April 1984 permitted continuance of solar flare observations that began in 1980. The SMM carries a soft X ray polychromator, gamma ray, UV and hard X ray imaging spectrometers, a coronagraph/polarimeter and particle counters. The data gathered thus far indicated that electrical potentials of 25 MeV develop in flares within 2 sec of onset. X ray data show that flares are composed of compressed magnetic loops that have come too close together. Other data have been taken on mass ejection, impacts of electron beams and conduction fronts with the chromosphere and changes in the solar radiant flux due to sunspots. 13 references

  19. Introduction to maximum entropy

    International Nuclear Information System (INIS)

    Sivia, D.S.

    1989-01-01

    The maximum entropy (MaxEnt) principle has been successfully used in image reconstruction in a wide variety of fields. The author reviews the need for such methods in data analysis and shows, by use of a very simple example, why MaxEnt is to be preferred over other regularizing functions. This leads to a more general interpretation of the MaxEnt method, and its use is illustrated with several different examples. Practical difficulties with non-linear problems still remain, this being highlighted by the notorious phase problem in crystallography. He concludes with an example from neutron scattering, using data from a filter difference spectrometer to contrast MaxEnt with a conventional deconvolution. 12 refs., 8 figs., 1 tab

  20. Functional Maximum Autocorrelation Factors

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Nielsen, Allan Aasbjerg

    2005-01-01

    MAF outperforms the functional PCA in concentrating the interesting' spectra/shape variation in one end of the eigenvalue spectrum and allows for easier interpretation of effects. Conclusions. Functional MAF analysis is a useful methods for extracting low dimensional models of temporally or spatially......Purpose. We aim at data where samples of an underlying function are observed in a spatial or temporal layout. Examples of underlying functions are reflectance spectra and biological shapes. We apply functional models based on smoothing splines and generalize the functional PCA in......\\verb+~+\\$\\backslash\\$cite{ramsay97} to functional maximum autocorrelation factors (MAF)\\verb+~+\\$\\backslash\\$cite{switzer85,larsen2001d}. We apply the method to biological shapes as well as reflectance spectra. {\\$\\backslash\\$bf Methods}. MAF seeks linear combination of the original variables that maximize autocorrelation between...

  1. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yunji; Jing, Bing-Yi; Gao, Xin

    2015-01-01

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  2. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan

    2015-02-12

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  3. Clarifying Normalization

    Science.gov (United States)

    Carpenter, Donald A.

    2008-01-01

    Confusion exists among database textbooks as to the goal of normalization as well as to which normal form a designer should aspire. This article discusses such discrepancies with the intention of simplifying normalization for both teacher and student. This author's industry and classroom experiences indicate such simplification yields quicker…

  4. Solar maximum mission

    International Nuclear Information System (INIS)

    Ryan, J.

    1981-01-01

    By understanding the sun, astrophysicists hope to expand this knowledge to understanding other stars. To study the sun, NASA launched a satellite on February 14, 1980. The project is named the Solar Maximum Mission (SMM). The satellite conducted detailed observations of the sun in collaboration with other satellites and ground-based optical and radio observations until its failure 10 months into the mission. The main objective of the SMM was to investigate one aspect of solar activity: solar flares. A brief description of the flare mechanism is given. The SMM satellite was valuable in providing information on where and how a solar flare occurs. A sequence of photographs of a solar flare taken from SMM satellite shows how a solar flare develops in a particular layer of the solar atmosphere. Two flares especially suitable for detailed observations by a joint effort occurred on April 30 and May 21 of 1980. These flares and observations of the flares are discussed. Also discussed are significant discoveries made by individual experiments

  5. Validation of reference genes for normalization of qPCR mRNA expression levels in Staphylococcus aureus exposed to osmotic and lactic acid stress conditions encountered during food production and preservation.

    Science.gov (United States)

    Sihto, Henna-Maria; Tasara, Taurai; Stephan, Roger; Johler, Sophia

    2014-07-01

    Staphylococcus aureus represents the most prevalent cause of food-borne intoxications worldwide. While being repressed by competing bacteria in most matrices, this pathogen exhibits crucial competitive advantages during growth at high salt concentrations or low pH, conditions frequently encountered in food production and preservation. We aimed to identify reference genes that could be used to normalize qPCR mRNA expression levels during growth of S. aureus in food-related osmotic (NaCl) and acidic (lactic acid) stress adaptation models. Expression stability of nine housekeeping genes was evaluated in full (LB) and nutrient-deficient (CYGP w/o glucose) medium under conditions of osmotic (4.5% NaCl) and acidic stress (lactic acid, pH 6.0) after 2-h exposure. Among the set of candidate reference genes investigated, rplD, rpoB,gyrB, and rho were most stably expressed in LB and thus represent the most suitable reference genes for normalization of qPCR data in osmotic or lactic acid stress models in a rich medium. Under nutrient-deficient conditions, expression of rho and rpoB was highly stable across all tested conditions. The presented comprehensive data on changes in expression of various S. aureus housekeeping genes under conditions of osmotic and lactic acid stress facilitate selection of reference genes for qPCR-based stress response models. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  6. Density estimation by maximum quantum entropy

    International Nuclear Information System (INIS)

    Silver, R.N.; Wallstrom, T.; Martz, H.F.

    1993-01-01

    A new Bayesian method for non-parametric density estimation is proposed, based on a mathematical analogy to quantum statistical physics. The mathematical procedure is related to maximum entropy methods for inverse problems and image reconstruction. The information divergence enforces global smoothing toward default models, convexity, positivity, extensivity and normalization. The novel feature is the replacement of classical entropy by quantum entropy, so that local smoothing is enforced by constraints on differential operators. The linear response of the estimate is proportional to the covariance. The hyperparameters are estimated by type-II maximum likelihood (evidence). The method is demonstrated on textbook data sets

  7. Birkhoff normalization

    NARCIS (Netherlands)

    Broer, H.; Hoveijn, I.; Lunter, G.; Vegter, G.

    2003-01-01

    The Birkhoff normal form procedure is a widely used tool for approximating a Hamiltonian systems by a simpler one. This chapter starts out with an introduction to Hamiltonian mechanics, followed by an explanation of the Birkhoff normal form procedure. Finally we discuss several algorithms for

  8. Stress Fractures

    Science.gov (United States)

    Stress fractures Overview Stress fractures are tiny cracks in a bone. They're caused by repetitive force, often from overuse — such as repeatedly jumping up and down or running long distances. Stress fractures can also arise from normal use of ...

  9. Calculation of thermal stress condition in long metal cylinder under heating by continuous laser radiation

    International Nuclear Information System (INIS)

    Uglov, A.A.; Uglov, S.A.; Kulik, A.N.

    1997-01-01

    The method of determination of temperature field and unduced thermal stresses in long metallic cylinder under its heating by cw-laser normally distributed heat flux is offered. The graphically presented results of calculation show the stress maximum is placed behind of center of laser heat sport along its movement line on the cylinder surface

  10. Prognostic value of normal stress myocardial perfusion imaging and ventricular function in Japanese asymptomatic patients with type 2 diabetes. A study of based on the J-ACCESS-2 database

    International Nuclear Information System (INIS)

    Matsuo, Shinro; Nakajima, Kenichi; Yamasaki, Yoshimitsu; Kashiwagi, Atsunori; Nishimura, Tsunehiko

    2010-01-01

    This study was designed to determine the clinical risk for hard events after normal single-photon emission computed tomography (SPECT) and to identify the predictors of increased risk in asymptomatic patients with diabetes mellitus, based on a Japanese Assessment of Cardiac Events and Survival Studies by quantitative gated SPECT (J-ACCESS)-2 study. A total of 513 consecutive asymptomatic patients who underwent stress 99m Tc-tetrofosmin SPECT in Japan were included in this study. Based on SPECT image and QGS data, 319 had a summed stress score ≤3, a summed difference score <2 and normal cardiac function (end-systolic volume ≤60 ml, males, ≤40 ml females; left ventricular ejection fraction ≥49%, males, ≥50% females). Myocardial perfusion was normal in 62% of this study population. During a 3-year follow-up, there were a total of 8 cardiac major events (2.5%): 2 cases of sudden death, 5 of acute coronary syndrome, and 1 of hospitalization because of congestive heart failure. The annual major event rate was 0.8%. Subjects undergoing coronary angiography had significantly more major events than those who did not among normal SPECT subjects (P=0.01). Kaplan-Meier analysis showed that the cardiac major events rate was very low, and subjects with normal SPECT can be considered as low risk among asymptomatic patients with diabetes. An excellent prognosis was associated with a normal SPECT in asymptomatic patients with diabetes, so these patients can be exempted from further invasive procedure. (author)

  11. Efficacy and safety of the trans-obturator TVT-Abbrevo device in normal weight compared to overweight patients affected by stress urinary incontinence.

    Science.gov (United States)

    Tommaselli, Giovanni A; Napolitano, Valerio; Di Carlo, Costantino; Formisano, Carmen; Fabozzi, Annamaria; Nappi, Carmine

    2016-02-01

    To investigate if TVT-Abbrevo has similar outcomes in normal weight and overweight patients. Retrospective evaluation of 205 (105 normal weight women and 100 overweight women with BMI ≥ 25 kg/m(2)) undergone TVT-Abbrevo positioning with 12 month follow-up. Primary outcomes were objective cure rate (defined as no leakage during CST) and subjective cure rate ("very much improved"/"much improved" at PGI-I), secondary outcomes were intra-operative and post-operative complications. Objective cure rates in the normal and overweight groups were 96.2% and 94%, respectively (p=.47). Subjective cure rates in the normal and overweight groups were 90.5% and 88%, respectively (p=.57). ICIQ-SF, I-QoL and PGI-S scores significantly improved in both groups with no differences between the two groups. No serious intra- or post-operative complications were observed. No differences were observed in pain VAS scores and number of analgesic vials administered. TVT-Abbrevo seems to have similar efficacy and safety in normal weight and overweight women. More studies are needed to assess the efficacy of this device in frankly obese women and long-term outcomes. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Auditory Discrimination of Lexical Stress Patterns in Hearing-Impaired Infants with Cochlear Implants Compared with Normal Hearing: Influence of Acoustic Cues and Listening Experience to the Ambient Language.

    Science.gov (United States)

    Segal, Osnat; Houston, Derek; Kishon-Rabin, Liat

    2016-01-01

    To assess discrimination of lexical stress pattern in infants with cochlear implant (CI) compared with infants with normal hearing (NH). While criteria for cochlear implantation have expanded to infants as young as 6 months, little is known regarding infants' processing of suprasegmental-prosodic cues which are known to be important for the first stages of language acquisition. Lexical stress is an example of such a cue, which, in hearing infants, has been shown to assist in segmenting words from fluent speech and in distinguishing between words that differ only the stress pattern. To date, however, there are no data on the ability of infants with CIs to perceive lexical stress. Such information will provide insight to the speech characteristics that are available to these infants in their first steps of language acquisition. This is of particular interest given the known limitations that the CI device has in transmitting speech information that is mediated by changes in fundamental frequency. Two groups of infants participated in this study. The first group included 20 profoundly hearing-impaired infants with CI, 12 to 33 months old, implanted under the age of 2.5 years (median age of implantation = 14.5 months), with 1 to 6 months of CI use (mean = 2.7 months) and no known additional problems. The second group of infants included 48 NH infants, 11 to 14 months old with normal development and no known risk factors for developmental delays. Infants were tested on their ability to discriminate between nonsense words that differed on their stress pattern only (/dóti/ versus /dotí/ and /dotí/ versus /dóti/) using the visual habituation procedure. The measure for discrimination was the change in looking time between the last habituation trial (e.g., /dóti/) and the novel trial (e.g., /dotí/). (1) Infants with CI showed discrimination between lexical stress pattern with only limited auditory experience with their implant device, (2) discrimination of stress

  13. Credal Networks under Maximum Entropy

    OpenAIRE

    Lukasiewicz, Thomas

    2013-01-01

    We apply the principle of maximum entropy to select a unique joint probability distribution from the set of all joint probability distributions specified by a credal network. In detail, we start by showing that the unique joint distribution of a Bayesian tree coincides with the maximum entropy model of its conditional distributions. This result, however, does not hold anymore for general Bayesian networks. We thus present a new kind of maximum entropy models, which are computed sequentially. ...

  14. Effect of Organic and Chemical Fertilizers on Yield and Essential Oil of Two Ecotypes of Savory (Satureja hortensis L. under Normal and Drought Stress Conditions

    Directory of Open Access Journals (Sweden)

    O Akrami nejad

    2016-02-01

    Full Text Available Introduction Savory (Satureja hortensis L. is an annual and aromatic plant from Labiatae family, which has plenty of essential oil and is important in medicinal, food, health and beauty industries (6. In comparison with chemical fertilizers, organic fertilizers especially manure have lots of organic material sources, and can be used as nutrients, especially Nitrogen, Phosphor and Potassium. Organic fertilizers also keeps more water in the soil (14. Water deficit is one of the most important boundaries of production in arid and semi-arid regions. Drought stress reduces water content, limits plant growth and changes some physiological and metabolic activities (31. This experiment was conducted as there is a global interest for production of medicinal plants with sustainable agriculture system, and with low input and shortage of information about Savory reaction to fertilization in drought stress condition. The objective of this research was to compare the effects of chemical fertilizers and different organic fertilizers on quantitative and qualitative characteristics of two ecotypes of savory under drought stress condition. Materials and Methods In order to study the effects of organic and mineral (N, P and K fertilizers on quantitative and qualitative characteristics of savory in drought stress condition, two separate split plot designs with three replications were carried out in 2012-2013 year, at the research field of Shahid Bahonar University of Kerman, Iran. In each design fertilizers including cow manure (30 ton per hectare, poultry manure (10 ton per hectare, chemical fertilizers (used equally with macro elements existing in both poultry and cow manure and control (no fertilizer were used as main factor. Kerman and Khuzestan ecotypes were sub-factor. One of the experiments was irrigated to 100% and the other to 50% of field capacity. Two experiments were analyzed as a combined design. The important characteristics of Savory such as plant

  15. The Efficiency and Safety of Tension-Free Vaginal Tape (TVT) Abbrevo Procedure Versus TVT Exact in the Normal Weight and Overweight Patients Affected by Stress Urinary Incontinence.

    Science.gov (United States)

    Sun, Yi; Luo, Deyi; Yang, Lu; Wei, Xin; Tang, Cai; Chen, Mei; Shen, Hong; Wei, Qiang

    2017-12-01

    To compare the efficacy between 2 different slings in normal weight and overweight women. Of 426 women, 220 (119 normal weight and 101 overweight) accepted the tension-free vaginal tape Abbrevo (TVT-A) and 206 (114 normal weight and 92 overweight) accepted the TVT Exact (TVT-E) procedure. Data collected contained the subjective efficiency, objective efficiency International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF), Incontinence Quality of Life Questionnaire (I-QOL), Pelvic Floor Impact Questionnaire-Short Form (PFIQ-7), Urogenital Distress Inventory-Short Form (UDI-6), and Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire-Short Form (PISQ)-12 at 36 months after surgery. In the normal weight patients, the subjectively and objectively cured rates were all high in both TVT-A and TVE-E (94.12% and 95.61% in objective result; 92.44% and 94.74% in subjective result). In addition, the score of I-QOL, PFIQ-7, and UDI-6 have significantly changed (P TVT-E than TVT-A. Moreover, the score of I-QOL, PFIQ-7, and UDI-6 of overweight women have significantly changed only in the TVT-E (P TVT-A and TVT-E, respectively). The TVT-E might be a better choice for the overweight patient than TVT-A. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Titanium Dioxide Nanoparticles Induce Endoplasmic Reticulum Stress-Mediated Autophagic Cell Death via Mitochondria-Associated Endoplasmic Reticulum Membrane Disruption in Normal Lung Cells

    Science.gov (United States)

    Yu, Kyeong-Nam; Chang, Seung-Hee; Park, Soo Jin; Lim, Joohyun; Lee, Jinkyu; Yoon, Tae-Jong; Kim, Jun-Sung; Cho, Myung-Haing

    2015-01-01

    Nanomaterials are used in diverse fields including food, cosmetic, and medical industries. Titanium dioxide nanoparticles (TiO2-NP) are widely used, but their effects on biological systems and mechanism of toxicity have not been elucidated fully. Here, we report the toxicological mechanism of TiO2-NP in cell organelles. Human bronchial epithelial cells (16HBE14o-) were exposed to 50 and 100 μg/mL TiO2-NP for 24 and 48 h. Our results showed that TiO2-NP induced endoplasmic reticulum (ER) stress in the cells and disrupted the mitochondria-associated endoplasmic reticulum membranes (MAMs) and calcium ion balance, thereby increasing autophagy. In contrast, an inhibitor of ER stress, tauroursodeoxycholic acid (TUDCA), mitigated the cellular toxic response, suggesting that TiO2-NP promoted toxicity via ER stress. This novel mechanism of TiO2-NP toxicity in human bronchial epithelial cells suggests that further exhaustive research on the harmful effects of these nanoparticles in relevant organisms is needed for their safe application. PMID:26121477

  17. An experimental study of the influence of stress history on fault slip during injection of supercritical CO2

    Science.gov (United States)

    Cuss, Robert J.; Wiseall, Andrew C.; Tamayo-Mas, Elena; Harrington, Jon F.

    2018-04-01

    The injection of super-critical CO2 into a depleted reservoir will alter the pore pressure of the basin, which if sufficiently perturbed could result in fault slip. Therefore, knowledge of the acceptable pressure limits is required in order to maintain fault stability. A two-part laboratory study was conducted on fully saturated kaolinite fault gouge to investigate this issue. Previously, we showed that fault slip occurred once pore-pressure within the gouge was sufficient to overcome the normal stress acting on the fault. For kaolinite, this behaviour occurred at a pressure similar to the yield stress. The current study shows that following a slow-reduction in the maximum principal stress, as would be expected through changes in effective stress, the reactivation pressure shows a stress memory. Consequently, the pressure necessary to initiate fault slip is similar to that required at the maximum stress encountered. Therefore, fault slip is at least partially controlled by the previous maximum stress and not the current stress state. During the slow reduction in normal stress, the flow characteristics of the fault remain unchanged until pore-pressure exceeds shear stress and does not increase significantly until it exceeds normal stress. This results in fault slip, which slows the rate of flow increase as shear is an effective self-sealing mechanism. These observations lead to the conclusion that stress history is a vital parameter when considering fault stability.

  18. Stress Concentration Factor and Stress Intensity Factor with U-notch and Crack in the Beam

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Bo Seong; Lee, Kwang Ho [Kyungpook National Univ., Daegu (Korea, Republic of)

    2016-05-15

    The stress concentration factors and stress intensity factors for a simple beam and a cantilever are analyzed by using finite element method and photoelasticity. Using the analyzed results, the estimated graphs on stress concentration factors and stress intensity factors are obtained. To analyze stress concentration factors of notch, the dimensionless notch length H(height of specimen)/h=1.1-2 and dimensionless gap space r(radius at the notch tip)/h=0.1~0.5 are used, where h=H-c and c is the notch length. As the notch gap length increases and the gap decreases, the stress concentration factors increase. Stress concentration factors of a simple beam are greater than those of a cantilever beam. However, actually, the maximum stress values under a load, a notch length and a gap occur more greatly in the cantilever beam than in the simple beam. To analyze stress intensity factors, the normalized crack length α(crack length)/H=0.2~0.5 is used. As the length of the crack increases, the normalized stress intensity factors increase. The stress intensity factors under a constant load and a crack length occur more greatly in the cantilever beam than in the simple beam.

  19. Malware Normalization

    OpenAIRE

    Christodorescu, Mihai; Kinder, Johannes; Jha, Somesh; Katzenbeisser, Stefan; Veith, Helmut

    2005-01-01

    Malware is code designed for a malicious purpose, such as obtaining root privilege on a host. A malware detector identifies malware and thus prevents it from adversely affecting a host. In order to evade detection by malware detectors, malware writers use various obfuscation techniques to transform their malware. There is strong evidence that commercial malware detectors are susceptible to these evasion tactics. In this paper, we describe the design and implementation of a malware normalizer ...

  20. Residual stresses determination in an 8 mm Incoloy 800H weld via neutron diffraction

    International Nuclear Information System (INIS)

    Chen, Xizhang; Zhang, Shu Yan; Wang, Jingjun; Kelleher, Joe F.

    2015-01-01

    Highlights: • Stress through thickness at 5 mm from weld centerline indicates a “U” distribution. • Declining of tensile stress through thickness occurred at weld centerline. • Residual stress between layers is the lowest. - Abstract: To investigate the distribution of residual stresses, the 8 mm 800H alloy was joined by multi-layer butt TIG process. Residual stresses in the longitudinal, transverse and normal directions were measured via neutron diffraction. These residual stress measurements were taken at a series of points 2 mm below the top surface, covering the fusion zone, heat affected zone (HAZ) and base metal. In addition, two lines of longitudinal residual stress values at the weld centerline and 5 mm from weld centerline through thickness were measured. Results show that both the longitudinal and transverse stresses from the weld centerline to base metal are mainly tensile stresses. The longitudinal residual stress is the largest, with a maximum value of 330 MPa. As for the normal residual stress, the weld zone shows tensile stress, while the HAZ shows compressive stress. The middle of the thickness shows compressive residual stress along the thickness direction. The longitudinal stress at weld centerline through thickness reveals the interlayer heat treat effects leads to a declining of tensile stress. While the stress at 5 mm from weld centerline indicates a “U” distribution due to the mixed microstructure close to fusion line. With the increasing distance from weld seam, the residual stress decreases gradually

  1. Mathematical model to determine the surface stress acting on the tooth of gear

    Directory of Open Access Journals (Sweden)

    Hinojosa-Torres J.

    2010-01-01

    Full Text Available Surface stress on the surface contact of gear tooth calculated by the Buckingham equation constitutes the basis for The American Gear Manufacturers Association (AGMA pitting resistance formula, which is based on a normal stress that does not cause failure since the yielding in contact problems is caused by shear stresses. An alternative expression based on the maximum-shear-stress is proposed in this paper. The new expression is obtained by using the maximum-shear-stress distribution and the Tresca failure criteria in order to know the maximum-shear-stress value and its location beneath the contact surface. Remarkable differences between the results using the proposed equation and those when the AGMA equation is applied are found.

  2. Stress-constrained topology optimization for compliant mechanism design

    DEFF Research Database (Denmark)

    de Leon, Daniel M.; Alexandersen, Joe; Jun, Jun S.

    2015-01-01

    This article presents an application of stress-constrained topology optimization to compliant mechanism design. An output displacement maximization formulation is used, together with the SIMP approach and a projection method to ensure convergence to nearly discrete designs. The maximum stress...... is approximated using a normalized version of the commonly-used p-norm of the effective von Mises stresses. The usual problems associated with topology optimization for compliant mechanism design: one-node and/or intermediate density hinges are alleviated by the stress constraint. However, it is also shown...

  3. Making nuclear 'normal'

    International Nuclear Information System (INIS)

    Haehlen, Peter; Elmiger, Bruno

    2000-01-01

    The mechanics of the Swiss NPPs' 'come and see' programme 1995-1999 were illustrated in our contributions to all PIME workshops since 1996. Now, after four annual 'waves', all the country has been covered by the NPPs' invitation to dialogue. This makes PIME 2000 the right time to shed some light on one particular objective of this initiative: making nuclear 'normal'. The principal aim of the 'come and see' programme, namely to give the Swiss NPPs 'a voice of their own' by the end of the nuclear moratorium 1990-2000, has clearly been attained and was commented on during earlier PIMEs. It is, however, equally important that Swiss nuclear energy not only made progress in terms of public 'presence', but also in terms of being perceived as a normal part of industry, as a normal branch of the economy. The message that Swiss nuclear energy is nothing but a normal business involving normal people, was stressed by several components of the multi-prong campaign: - The speakers in the TV ads were real - 'normal' - visitors' guides and not actors; - The testimonials in the print ads were all real NPP visitors - 'normal' people - and not models; - The mailings inviting a very large number of associations to 'come and see' activated a typical channel of 'normal' Swiss social life; - Spending money on ads (a new activity for Swiss NPPs) appears to have resulted in being perceived by the media as a normal branch of the economy. Today we feel that the 'normality' message has well been received by the media. In the controversy dealing with antinuclear arguments brought forward by environmental organisations journalists nowadays as a rule give nuclear energy a voice - a normal right to be heard. As in a 'normal' controversy, the media again actively ask themselves questions about specific antinuclear claims, much more than before 1990 when the moratorium started. The result is that in many cases such arguments are discarded by journalists, because they are, e.g., found to be

  4. Overall bolt stress optimization

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The state of stress in bolts and nuts with International Organization for Standardization metric thread design is examined and optimized. The assumed failure mode is fatigue, so the applied preload and the load amplitude together with the stress concentrations define the connection strength....... Maximum stress in the bolt is found at the fillet under the head, at the thread start, or at the thread root. To minimize the stress concentration, shape optimization is applied. Nut shape optimization also has a positive effect on the maximum stress. The optimization results show that designing a nut......, which results in a more evenly distribution of load along the engaged thread, has a limited influence on the maximum stress due to the stress concentration at the first thread root. To further reduce the maximum stress, the transition from bolt shank to the thread must be optimized. Stress reduction...

  5. Normalized Rotational Multiple Yield Surface Framework (NRMYSF) stress-strain curve prediction method based on small strain triaxial test data on undisturbed Auckland residual clay soils

    Science.gov (United States)

    Noor, M. J. Md; Ibrahim, A.; Rahman, A. S. A.

    2018-04-01

    Small strain triaxial test measurement is considered to be significantly accurate compared to the external strain measurement using conventional method due to systematic errors normally associated with the test. Three submersible miniature linear variable differential transducer (LVDT) mounted on yokes which clamped directly onto the soil sample at equally 120° from the others. The device setup using 0.4 N resolution load cell and 16 bit AD converter was capable of consistently resolving displacement of less than 1µm and measuring axial strains ranging from less than 0.001% to 2.5%. Further analysis of small strain local measurement data was performed using new Normalized Multiple Yield Surface Framework (NRMYSF) method and compared with existing Rotational Multiple Yield Surface Framework (RMYSF) prediction method. The prediction of shear strength based on combined intrinsic curvilinear shear strength envelope using small strain triaxial test data confirmed the significant improvement and reliability of the measurement and analysis methods. Moreover, the NRMYSF method shows an excellent data prediction and significant improvement toward more reliable prediction of soil strength that can reduce the cost and time of experimental laboratory test.

  6. Normal accidents

    International Nuclear Information System (INIS)

    Perrow, C.

    1989-01-01

    The author has chosen numerous concrete examples to illustrate the hazardousness inherent in high-risk technologies. Starting with the TMI reactor accident in 1979, he shows that it is not only the nuclear energy sector that bears the risk of 'normal accidents', but also quite a number of other technologies and industrial sectors, or research fields. The author refers to the petrochemical industry, shipping, air traffic, large dams, mining activities, and genetic engineering, showing that due to the complexity of the systems and their manifold, rapidly interacting processes, accidents happen that cannot be thoroughly calculated, and hence are unavoidable. (orig./HP) [de

  7. Exercise-induced maximum metabolic rate scaled to body mass by ...

    African Journals Online (AJOL)

    Exercise-induced maximum metabolic rate scaled to body mass by the fractal ... rate scaling is that exercise-induced maximum aerobic metabolic rate (MMR) is ... muscle stress limitation, and maximized oxygen delivery and metabolic rates.

  8. Effects of dietary Lactobacillus plantarum in different treatments on growth performance and immune gene expression of white shrimp Litopenaeus vannamei under normal condition and stress of acute low salinity.

    Science.gov (United States)

    Zheng, Xiaoting; Duan, Yafei; Dong, Hongbiao; Zhang, Jiasong

    2017-03-01

    A 45-day feeding trial followed by an acute stress test of low salinity was done to evaluate effects of Lactobacillus plantarum on growth performance and anti-stress capability of white shrimp (Litopenaeus vannamei). Shrimp were randomly allocated in 15 tanks (100 shrimp per tank) and divided into 5 treatments with 3 replicates. Triplicate tanks were fed with a control diet or diets containing different treatments of L. plantarum (fermentation supernatant (FS), live bacteria (LB), dead bacteria (DB) and cell-free extract (CE) of L. plantarum) as treatment groups. Growth performance including weight gain (WGR), feed conversion ratio (FCR) and specific growth rate (SGR) were determined after feeding 45 days. Anti-stress capacity was evaluated by determining the gene expression of ProPO, SOD and Lys in gut of shrimp at the end of feeding trial and again at 96 h post-stress test. Results indicated that supplementation of L. plantarum into diet had significantly improved growth performance of L. vannamei. On the other hand, L. plantarum supplementation had no significant effects on the gene expression of SOD and Lys in gut of shrimp cultured under normal condition for 45 days. Supplementation of L. plantarum had increased survivability of L. vannamei having higher survival rates compared to the control group. However, statistical analysis showed no significant difference between the control group and treatments. Compared with the control group, supplementation of L. plantarum significantly improved the resistance of L. vannamei against the stress of acute low salinity, as indicated by higher survival rate as well as higher transcript levels of ProPo, SOD and Lys gene. Our findings suggested that L. plantarum, especially cell-free extract of L. plantarum has improved the anti-stress capacity of L. vannamei and could serve as a potential feed additive that helps shrimp to overcome environmental stresses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Reconstructing Normality

    DEFF Research Database (Denmark)

    Gildberg, Frederik Alkier; Bradley, Stephen K.; Fristed, Peter Billeskov

    2012-01-01

    Forensic psychiatry is an area of priority for the Danish Government. As the field expands, this calls for increased knowledge about mental health nursing practice, as this is part of the forensic psychiatry treatment offered. However, only sparse research exists in this area. The aim of this study...... was to investigate the characteristics of forensic mental health nursing staff interaction with forensic mental health inpatients and to explore how staff give meaning to these interactions. The project included 32 forensic mental health staff members, with over 307 hours of participant observations, 48 informal....... The intention is to establish a trusting relationship to form behaviour and perceptual-corrective care, which is characterized by staff's endeavours to change, halt, or support the patient's behaviour or perception in relation to staff's perception of normality. The intention is to support and teach the patient...

  10. Pursuing Normality

    DEFF Research Database (Denmark)

    Madsen, Louise Sofia; Handberg, Charlotte

    2018-01-01

    implying an influence on whether to participate in cancer survivorship care programs. Because of "pursuing normality," 8 of 9 participants opted out of cancer survivorship care programming due to prospects of "being cured" and perceptions of cancer survivorship care as "a continuation of the disease......BACKGROUND: The present study explored the reflections on cancer survivorship care of lymphoma survivors in active treatment. Lymphoma survivors have survivorship care needs, yet their participation in cancer survivorship care programs is still reported as low. OBJECTIVE: The aim of this study...... was to understand the reflections on cancer survivorship care of lymphoma survivors to aid the future planning of cancer survivorship care and overcome barriers to participation. METHODS: Data were generated in a hematological ward during 4 months of ethnographic fieldwork, including participant observation and 46...

  11. Maximum Entropy in Drug Discovery

    Directory of Open Access Journals (Sweden)

    Chih-Yuan Tseng

    2014-07-01

    Full Text Available Drug discovery applies multidisciplinary approaches either experimentally, computationally or both ways to identify lead compounds to treat various diseases. While conventional approaches have yielded many US Food and Drug Administration (FDA-approved drugs, researchers continue investigating and designing better approaches to increase the success rate in the discovery process. In this article, we provide an overview of the current strategies and point out where and how the method of maximum entropy has been introduced in this area. The maximum entropy principle has its root in thermodynamics, yet since Jaynes’ pioneering work in the 1950s, the maximum entropy principle has not only been used as a physics law, but also as a reasoning tool that allows us to process information in hand with the least bias. Its applicability in various disciplines has been abundantly demonstrated. We give several examples of applications of maximum entropy in different stages of drug discovery. Finally, we discuss a promising new direction in drug discovery that is likely to hinge on the ways of utilizing maximum entropy.

  12. Precaval retropancreatic space: Normal anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yeon Hee; Kim, Ki Whang; Kim, Myung Jin; Yoo, Hyung Sik; Lee, Jong Tae [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1992-07-15

    The authors defined precaval retropancreatic space as the space between pancreatic head with portal vein and IVC and analyzed the CT findings of this space to know the normal structures and size in this space. We evaluated 100 cases of normal abdominal CT scan to find out normal anatomic structures of precaval retropancreatic space retrospectively. We also measured the distance between these structures and calculated the minimum, maximum and mean values. At the splenoportal confluence level, normal structures between portal vein and IVC were vessel (21%), lymph node (19%), and caudate lobe of liver (2%) in order of frequency. The maximum AP diameter of portocaval lymph node was 4 mm. Common bile duct (CBD) was seen in 44% and the diameter was mean 3 mm and maximum 11 mm. CBD was located in extrapancreatic (75%) and lateral (60.6%) to pancreatic head. At IVC-left renal vein level, the maximum distance between CBD and IVC was 5 mm and the structure between posterior pancreatic surface and IVC was only fat tissue. Knowledge of these normal structures and measurement will be helpful in differentiating pancreatic mass with retropancreatic mass such as lymphadenopathy.

  13. Chondroitin 4-O-Sulfotransferase Is Indispensable for Sulfation of Chondroitin and Plays an Important Role in Maintaining Normal Life Span and Oxidative Stress Responses in Nematodes*

    Science.gov (United States)

    Izumikawa, Tomomi; Dejima, Katsufumi; Watamoto, Yukiko; Nomura, Kazuko H.; Kanaki, Nanako; Rikitake, Marika; Tou, Mai; Murata, Daisuke; Yanagita, Eri; Kano, Ai; Mitani, Shohei; Nomura, Kazuya; Kitagawa, Hiroshi

    2016-01-01

    Chondroitin sulfate (CS)/chondroitin (Chn) chains are indispensable for embryonic cell division and cytokinesis in the early developmental stages in Caenorhabditis elegans and mice, whereas heparan sulfate (HS) is essential for axon guidance during nervous system development. These data indicate that the fundamental functions of CS and HS are conserved from worms to mammals and that the function of CS/Chn differs from that of HS. Although previous studies have shown that C. elegans produces HS and non-sulfated Chn, whether the organism produces CS remains unclear. Here, we demonstrate that C. elegans produces a small amount of 4-O-sulfated Chn and report the identification of C41C4.1, an orthologue of the human chondroitin 4-O-sulfotransferase gene. Loss of C41C4.1 in C. elegans resulted in a decline in 4-O-sulfation of CS and an increase in the number of sulfated units in HS. C41C4.1 deletion mutants exhibited reduced survival rates after synchronization with sodium hypochlorite. Collectively, these results show for the first time that CS glycans are present in C. elegans and that the Chn 4-O-sulfotransferase responsible for the sulfation plays an important role in protecting nematodes from oxidative stress. PMID:27645998

  14. Chondroitin 4-O-Sulfotransferase Is Indispensable for Sulfation of Chondroitin and Plays an Important Role in Maintaining Normal Life Span and Oxidative Stress Responses in Nematodes.

    Science.gov (United States)

    Izumikawa, Tomomi; Dejima, Katsufumi; Watamoto, Yukiko; Nomura, Kazuko H; Kanaki, Nanako; Rikitake, Marika; Tou, Mai; Murata, Daisuke; Yanagita, Eri; Kano, Ai; Mitani, Shohei; Nomura, Kazuya; Kitagawa, Hiroshi

    2016-10-28

    Chondroitin sulfate (CS)/chondroitin (Chn) chains are indispensable for embryonic cell division and cytokinesis in the early developmental stages in Caenorhabditis elegans and mice, whereas heparan sulfate (HS) is essential for axon guidance during nervous system development. These data indicate that the fundamental functions of CS and HS are conserved from worms to mammals and that the function of CS/Chn differs from that of HS. Although previous studies have shown that C. elegans produces HS and non-sulfated Chn, whether the organism produces CS remains unclear. Here, we demonstrate that C. elegans produces a small amount of 4-O-sulfated Chn and report the identification of C41C4.1, an orthologue of the human chondroitin 4-O-sulfotransferase gene. Loss of C41C4.1 in C. elegans resulted in a decline in 4-O-sulfation of CS and an increase in the number of sulfated units in HS. C41C4.1 deletion mutants exhibited reduced survival rates after synchronization with sodium hypochlorite. Collectively, these results show for the first time that CS glycans are present in C. elegans and that the Chn 4-O-sulfotransferase responsible for the sulfation plays an important role in protecting nematodes from oxidative stress. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Effects of UVB-induced oxidative stress on protein expression and specific protein oxidation in normal human epithelial keratinocytes: a proteomic approach

    Directory of Open Access Journals (Sweden)

    De Marco Federico

    2010-03-01

    Full Text Available Abstract Background The UVB component of solar ultraviolet irradiation is one of the major risk factors for the development of skin cancer in humans. UVB exposure elicits an increased generation of reactive oxygen species (ROS, which are responsible for oxidative damage to proteins, DNA, RNA and lipids. In order to examine the biological impact of UVB irradiation on skin cells, we used a parallel proteomics approach to analyze the protein expression profile and to identify oxidatively modified proteins in normal human epithelial keratinocytes. Results The expression levels of fifteen proteins - involved in maintaining the cytoskeleton integrity, removal of damaged proteins and heat shock response - were differentially regulated in UVB-exposed cells, indicating that an appropriate response is developed in order to counteract/neutralize the toxic effects of UVB-raised ROS. On the other side, the redox proteomics approach revealed that seven proteins - involved in cellular adhesion, cell-cell interaction and protein folding - were selectively oxidized. Conclusions Despite a wide and well orchestrated cellular response, a relevant oxidation of specific proteins concomitantly occurs in UVB-irradiated human epithelial Keratinocytes. These modified (i.e. likely dysfunctional proteins might result in cell homeostasis impairment and therefore eventually promote cellular degeneration, senescence or carcinogenesis.

  16. On the maximum entropy distributions of inherently positive nuclear data

    Energy Technology Data Exchange (ETDEWEB)

    Taavitsainen, A., E-mail: aapo.taavitsainen@gmail.com; Vanhanen, R.

    2017-05-11

    The multivariate log-normal distribution is used by many authors and statistical uncertainty propagation programs for inherently positive quantities. Sometimes it is claimed that the log-normal distribution results from the maximum entropy principle, if only means, covariances and inherent positiveness of quantities are known or assumed to be known. In this article we show that this is not true. Assuming a constant prior distribution, the maximum entropy distribution is in fact a truncated multivariate normal distribution – whenever it exists. However, its practical application to multidimensional cases is hindered by lack of a method to compute its location and scale parameters from means and covariances. Therefore, regardless of its theoretical disadvantage, use of other distributions seems to be a practical necessity. - Highlights: • Statistical uncertainty propagation requires a sampling distribution. • The objective distribution of inherently positive quantities is determined. • The objectivity is based on the maximum entropy principle. • The maximum entropy distribution is the truncated normal distribution. • Applicability of log-normal or normal distribution approximation is limited.

  17. Maximum stellar iron core mass

    Indian Academy of Sciences (India)

    60, No. 3. — journal of. March 2003 physics pp. 415–422. Maximum stellar iron core mass. F W GIACOBBE. Chicago Research Center/American Air Liquide ... iron core compression due to the weight of non-ferrous matter overlying the iron cores within large .... thermal equilibrium velocities will tend to be non-relativistic.

  18. Maximum entropy beam diagnostic tomography

    International Nuclear Information System (INIS)

    Mottershead, C.T.

    1985-01-01

    This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore. 11 refs., 4 figs

  19. Maximum entropy beam diagnostic tomography

    International Nuclear Information System (INIS)

    Mottershead, C.T.

    1985-01-01

    This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore

  20. A portable storage maximum thermometer

    International Nuclear Information System (INIS)

    Fayart, Gerard.

    1976-01-01

    A clinical thermometer storing the voltage corresponding to the maximum temperature in an analog memory is described. End of the measurement is shown by a lamp switch out. The measurement time is shortened by means of a low thermal inertia platinum probe. This portable thermometer is fitted with cell test and calibration system [fr

  1. Characteristics of images of angiographically proven normal coronary arteries acquired by adenosine-stress thallium-201 myocardial perfusion SPECT/CT-IQ[Symbol: see text]SPECT with CT attenuation correction changed stepwise.

    Science.gov (United States)

    Takahashi, Teruyuki; Tanaka, Haruki; Kozono, Nami; Tanakamaru, Yoshiki; Idei, Naomi; Ohashi, Norihiko; Ohtsubo, Hideki; Okada, Takenori; Yasunobu, Yuji; Kaseda, Shunichi

    2015-04-01

    Although several studies have shown the diagnostic and prognostic value of CT-based attenuation correction (AC) of single photon emission computed tomography (SPECT) images for diagnosing coronary artery disease (CAD), this issue remains a matter of debate. To clarify the characteristics of CT-AC SPECT images that might potentially improve diagnostic performance, we analyzed images acquired using adenosine-stress thallium-201 myocardial perfusion SPECT/CT equipped with IQ[Symbol: see text]SPECT (SPECT/CT-IQ[Symbol: see text]SPECT) from patients with angiographically proven normal coronary arteries after changing the CT attenuation correction (CT-AC) in a stepwise manner. We enrolled 72 patients (Male 36, Female 36) with normal coronary arteries according to findings of invasive coronary angiography or CT-angiography within three months after a SPECT/CT study. Projection images were reconstructed at CT-AC values of (-), 40, 60, 80 and 100 % using a CT number conversion program according to our definition and analyzed using polar maps according to sex. CT attenuation corrected segments were located from the mid- and apical-inferior spread through the mid- and apical-septal regions and finally to the basal-anterior and basal- and mid-lateral regions in males, and from the mid-inferior region through the mid-septal and mid-anterior, and mid-lateral regions in females as the CT-AC values increased. Segments with maximal mean counts shifted from the apical-anterior to mid-anterolateral region under both stress and rest conditions in males, whereas such segments shifted from the apical-septal to the mid-anteroseptal region under both stress and rest conditions in females. We clarified which part of the myocardium and to which degree CT-AC affects it in adenosine-stress thallium-201 myocardial perfusion SPECT/CT-IQ[Symbol: see text]SPECT images by changing the CT-AC value stepwise. We also identified sex-specific shifts of segments with maximal mean counts that changed as

  2. Neutron spectra unfolding with maximum entropy and maximum likelihood

    International Nuclear Information System (INIS)

    Itoh, Shikoh; Tsunoda, Toshiharu

    1989-01-01

    A new unfolding theory has been established on the basis of the maximum entropy principle and the maximum likelihood method. This theory correctly embodies the Poisson statistics of neutron detection, and always brings a positive solution over the whole energy range. Moreover, the theory unifies both problems of overdetermined and of underdetermined. For the latter, the ambiguity in assigning a prior probability, i.e. the initial guess in the Bayesian sense, has become extinct by virtue of the principle. An approximate expression of the covariance matrix for the resultant spectra is also presented. An efficient algorithm to solve the nonlinear system, which appears in the present study, has been established. Results of computer simulation showed the effectiveness of the present theory. (author)

  3. Isolation of mouse mesenchymal stem cells with normal ploidy from bone marrows by reducing oxidative stress in combination with extracellular matrix

    Directory of Open Access Journals (Sweden)

    Wang Fang

    2011-07-01

    Full Text Available Abstract Background Isolation of mouse MSCs (mMSCs with normal ploidy from bone marrow remains challenging. mMSCs isolated under 20% O2 are frequently contaminated by overgrown hematopoietic cells, and could also be especially vulnerable to oxidative damage, resulting in chromosomal instability. Culture under low oxygen or extracellular matrix (ECM improves proliferation of MSCs in several species. We tested the hypothesis that culture under low oxygen in combination with ECM prepared from mouse embryonic fibroblast (MEF-ECM could be used to purify proliferative mMSCs, and to reduce oxidative damage and maintain their chromosomal stability. Results Optimization of culture conditions under 20% O2 resulted in immortalization of mMSCs, showing extensive chromosome abnormalities, consistent with previous studies. In contrast, culture under low oxygen (2% O2 improved proliferation of mMSCs and reduced oxidative damage, such that mMSCs were purified simply by plating at low density under 2% O2. MEF-ECM reduced oxidative damage and enhanced proliferation of mMSCs. However, these isolated mMSCs still exhibited high frequency of chromosome abnormalities, suggesting that low oxygen or in combination with MEF-ECM was insufficient to fully protect mMSCs from oxidative damage. Notably, antioxidants (alpha -phenyl-t-butyl nitrone (PBN and N-acetylcysteine (NAC further reduced DNA damage and chromosomal abnormalities, and increased proliferation of mMSCs. mMSCs isolated by the combination method were successfully used to generate induced pluripotent stem (iPS cells by ectopic expression of Oct4, Sox2, Klf4 and c-Myc. Conclusions We have developed a technique that allows to reduce the number of karyotypic abnormalities for isolation of primary mMSCs and for limited culture period by combination of low oxygen, MEF-ECM, antioxidants and low density plating strategy. The effectiveness of the new combination method is demonstrated by successful generation of i

  4. Combining Earthquake Focal Mechanism Inversion and Coulomb Friction Law to Yield Tectonic Stress Magnitudes in Strike-slip Faulting Regime

    Science.gov (United States)

    Soh, I.; Chang, C.

    2017-12-01

    The techniques for estimating present-day stress states by inverting multiple earthquake focal mechanism solutions (FMS) provide orientations of the three principal stresses and their relative magnitudes. In order to estimate absolute magnitudes of the stresses that are generally required to analyze faulting mechanics, we combine the relative stress magnitude parameter (R-value) derived from the inversion process and the concept of frictional equilibrium of stress state defined by Coulomb friction law. The stress inversion in Korean Peninsula using 152 FMS data (magnitude≥2.5) conducted at regularly spaced grid points yields a consistent strike-slip faulting regime in which the maximum (S1) and the minimum (S3) principal stresses act in horizontal planes (with an S1 azimuth in ENE-WSW) and the intermediate principal stress (S2) close to vertical. However, R-value varies from 0.28 to 0.75 depending on locations, systematically increasing eastward. Based on the assumptions that the vertical stress is lithostatic, pore pressure is hydrostatic, and the maximum differential stress (S1-S3) is limited by Byerlee's friction of optimally oriented faults for slip, we estimate absolute magnitudes of the two horizontal principal stresses using R-value. As R-value increases, so do the magnitudes of the horizontal stresses. Our estimation of the stress magnitudes shows that the maximum horizontal principal stress (S1) normalized by vertical stress tends to increase from 1.3 in the west to 1.8 in the east. The estimated variation of stress magnitudes is compatible with distinct clustering of faulting types in different regions. Normal faulting events are densely populated in the west region where the horizontal stress is relatively low, whereas numerous reverse faulting events prevail in the east offshore where the horizontal stress is relatively high. Such a characteristic distribution of distinct faulting types in different regions can only be explained in terms of stress

  5. On Maximum Entropy and Inference

    Directory of Open Access Journals (Sweden)

    Luigi Gresele

    2017-11-01

    Full Text Available Maximum entropy is a powerful concept that entails a sharp separation between relevant and irrelevant variables. It is typically invoked in inference, once an assumption is made on what the relevant variables are, in order to estimate a model from data, that affords predictions on all other (dependent variables. Conversely, maximum entropy can be invoked to retrieve the relevant variables (sufficient statistics directly from the data, once a model is identified by Bayesian model selection. We explore this approach in the case of spin models with interactions of arbitrary order, and we discuss how relevant interactions can be inferred. In this perspective, the dimensionality of the inference problem is not set by the number of parameters in the model, but by the frequency distribution of the data. We illustrate the method showing its ability to recover the correct model in a few prototype cases and discuss its application on a real dataset.

  6. Maximum Water Hammer Sensitivity Analysis

    OpenAIRE

    Jalil Emadi; Abbas Solemani

    2011-01-01

    Pressure waves and Water Hammer occur in a pumping system when valves are closed or opened suddenly or in the case of sudden failure of pumps. Determination of maximum water hammer is considered one of the most important technical and economical items of which engineers and designers of pumping stations and conveyance pipelines should take care. Hammer Software is a recent application used to simulate water hammer. The present study focuses on determining significance of ...

  7. Maximum Gene-Support Tree

    Directory of Open Access Journals (Sweden)

    Yunfeng Shan

    2008-01-01

    Full Text Available Genomes and genes diversify during evolution; however, it is unclear to what extent genes still retain the relationship among species. Model species for molecular phylogenetic studies include yeasts and viruses whose genomes were sequenced as well as plants that have the fossil-supported true phylogenetic trees available. In this study, we generated single gene trees of seven yeast species as well as single gene trees of nine baculovirus species using all the orthologous genes among the species compared. Homologous genes among seven known plants were used for validation of the finding. Four algorithms—maximum parsimony (MP, minimum evolution (ME, maximum likelihood (ML, and neighbor-joining (NJ—were used. Trees were reconstructed before and after weighting the DNA and protein sequence lengths among genes. Rarely a gene can always generate the “true tree” by all the four algorithms. However, the most frequent gene tree, termed “maximum gene-support tree” (MGS tree, or WMGS tree for the weighted one, in yeasts, baculoviruses, or plants was consistently found to be the “true tree” among the species. The results provide insights into the overall degree of divergence of orthologous genes of the genomes analyzed and suggest the following: 1 The true tree relationship among the species studied is still maintained by the largest group of orthologous genes; 2 There are usually more orthologous genes with higher similarities between genetically closer species than between genetically more distant ones; and 3 The maximum gene-support tree reflects the phylogenetic relationship among species in comparison.

  8. LCLS Maximum Credible Beam Power

    International Nuclear Information System (INIS)

    Clendenin, J.

    2005-01-01

    The maximum credible beam power is defined as the highest credible average beam power that the accelerator can deliver to the point in question, given the laws of physics, the beam line design, and assuming all protection devices have failed. For a new accelerator project, the official maximum credible beam power is determined by project staff in consultation with the Radiation Physics Department, after examining the arguments and evidence presented by the appropriate accelerator physicist(s) and beam line engineers. The definitive parameter becomes part of the project's safety envelope. This technical note will first review the studies that were done for the Gun Test Facility (GTF) at SSRL, where a photoinjector similar to the one proposed for the LCLS is being tested. In Section 3 the maximum charge out of the gun for a single rf pulse is calculated. In Section 4, PARMELA simulations are used to track the beam from the gun to the end of the photoinjector. Finally in Section 5 the beam through the matching section and injected into Linac-1 is discussed

  9. Three-Dimensional Normal Human Neural Progenitor Tissue-Like Assemblies: A Model for Persistent Varicell-Zoster Virus Infection and Platform to Study Viral Infectivity and Oxidative Stress and Damage

    Science.gov (United States)

    Goodwin, T. J.; McCarthy, M.; Osterrieder, N.; Cohrs, R. J.; Kaufer, B. B.

    2014-01-01

    The environment of space results in a multitude of challenges to the human physiology that present barriers to extended habitation and exploration. Over 40 years of investigation to define countermeasures to address space flight adaptation has left gaps in our knowledge regarding mitigation strategies partly due to the lack of investigative tools, monitoring strategies, and real time diagnostics to understand the central causative agent(s) responsible for physiologic adaptation and maintaining homeostasis. Spaceflight-adaptation syndrome is the combination of space environmental conditions and the synergistic reaction of the human physiology. Our work addresses the role of oxidative stress and damage (OSaD) as a negative and contributing Risk Factor (RF) in the following areas of combined spaceflight related dysregulation: i) radiation induced cellular damage [1], [2] ii) immune impacts and the inflammatory response [3], [4] and iii) varicella zoster virus (VZV) reactivation [5]. Varicella-zoster (VZV)/Chicken Pox virus is a neurotropic human alphaherpesvirus resulting in varicella upon primary infection, suppressed by the immune system becomes latent in ganglionic neurons, and reactivates under stress events to re-express in zoster and possibly shingles. Our laboratory has developed a complex threedimensional (3D) normal human neural tissue model that emulates several characteristics of the human trigeminal ganglia (TG) and allows the study of combinatorial experimentation which addresses, simultaneously, OSaD associated with Spaceflight adaptation and habitation [6].

  10. Environmental exposure to lead induces oxidative stress and modulates the function of the antioxidant defense system and the immune system in the semen of males with normal semen profile

    Energy Technology Data Exchange (ETDEWEB)

    Kasperczyk, Aleksandra; Dobrakowski, Michał [Dept. of Biochemistry, School of Medicine with the Division of Dentistry, Medical University of Silesia, Katowice, Jordana 19, 41-808 Zabrze (Poland); Czuba, Zenon P. [Dept. of Microbiology and Immunology, School of Medicine with the Division of Dentistry, Medical University of Silesia, Katowice, Jordana 19, 41-808 Zabrze (Poland); Horak, Stanisław [I-st Chair and Clin. Dept. of Gynecology, Obstetrics and Gynecological Oncology, School of Medicine with the Division of Dentistry, Medical University of Silesia, Katowice, Batorego 15, 41-902 Bytom (Poland); Kasperczyk, Sławomir, E-mail: kaslav@mp.pl [Dept. of Biochemistry, School of Medicine with the Division of Dentistry, Medical University of Silesia, Katowice, Jordana 19, 41-808 Zabrze (Poland)

    2015-05-01

    We investigated the associations between environmental exposure to lead and a repertoire of cytokines in seminal plasma of males with normal semen profile according to the WHO criteria. Based on the median lead concentration in seminal plasma, 65 samples were divided into two groups: low (LE) and high exposure to lead (HE). Differences in semen volume and the pH, count, motility and morphology of sperm cells were not observed between the examined groups. The total oxidant status value and the level of protein sulfhydryl groups as well as the activities of manganese superoxide dismutase and catalase were significantly higher in the HE group, whereas the total antioxidant capacity value and the activities of glutathione reductase and glutathione-S-transferase were depressed. IL-7, IL-10, IL-12, and TNF-α levels were significantly higher in the HE group compared with the LE group. Environmental exposure to lead is sufficient to induce oxidative stress in seminal plasma and to modulate antioxidant defense system. - Highlights: • Lead induces oxidative stress in seminal plasma in human. • Lead modulates antioxidant defense system in seminal plasma in human. • Lead does not change a Th1/Th2 imbalance in seminal plasma in human.

  11. Generic maximum likely scale selection

    DEFF Research Database (Denmark)

    Pedersen, Kim Steenstrup; Loog, Marco; Markussen, Bo

    2007-01-01

    in this work is on applying this selection principle under a Brownian image model. This image model provides a simple scale invariant prior for natural images and we provide illustrative examples of the behavior of our scale estimation on such images. In these illustrative examples, estimation is based......The fundamental problem of local scale selection is addressed by means of a novel principle, which is based on maximum likelihood estimation. The principle is generally applicable to a broad variety of image models and descriptors, and provides a generic scale estimation methodology. The focus...

  12. Extreme Maximum Land Surface Temperatures.

    Science.gov (United States)

    Garratt, J. R.

    1992-09-01

    There are numerous reports in the literature of observations of land surface temperatures. Some of these, almost all made in situ, reveal maximum values in the 50°-70°C range, with a few, made in desert regions, near 80°C. Consideration of a simplified form of the surface energy balance equation, utilizing likely upper values of absorbed shortwave flux (1000 W m2) and screen air temperature (55°C), that surface temperatures in the vicinity of 90°-100°C may occur for dry, darkish soils of low thermal conductivity (0.1-0.2 W m1 K1). Numerical simulations confirm this and suggest that temperature gradients in the first few centimeters of soil may reach 0.5°-1°C mm1 under these extreme conditions. The study bears upon the intrinsic interest of identifying extreme maximum temperatures and yields interesting information regarding the comfort zone of animals (including man).

  13. Pressure Dependence of the Peierls Stress in Aluminum

    Science.gov (United States)

    Dang, Khanh; Spearot, Douglas

    2018-03-01

    The effect of pressure applied normal to the {111} slip plane on the Peierls stress in Al is studied via atomistic simulations. Edge, screw, 30°, and 60° straight dislocations are created using the Volterra displacement fields for isotropic elasticity. For each dislocation character angle, the Peierls stress is calculated based on the change in the internal energy, which is an invariant measure of the dislocation driving force. It is found that the Peierls stress for dislocations under zero pressure is in general agreement with previous results. For screw and 60° dislocations, the Peierls stress versus pressure relationship has maximum values associated with stacking fault widths that are multiples of the Peierls period. For the edge dislocation, the Peierls stress decreases with increasing pressure from tension to compression. Compared with the Mendelev potential, the Peierls stress calculated from the Mishin potential is more sensitive to changes in pressure.

  14. Heat Convection at the Density Maximum Point of Water

    Science.gov (United States)

    Balta, Nuri; Korganci, Nuri

    2018-01-01

    Water exhibits a maximum in density at normal pressure at around 4° degree temperature. This paper demonstrates that during cooling, at around 4 °C, the temperature remains constant for a while because of heat exchange associated with convective currents inside the water. Superficial approach implies it as a new anomaly of water, but actually it…

  15. System for memorizing maximum values

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1992-08-01

    The invention discloses a system capable of memorizing maximum sensed values. The system includes conditioning circuitry which receives the analog output signal from a sensor transducer. The conditioning circuitry rectifies and filters the analog signal and provides an input signal to a digital driver, which may be either linear or logarithmic. The driver converts the analog signal to discrete digital values, which in turn triggers an output signal on one of a plurality of driver output lines n. The particular output lines selected is dependent on the converted digital value. A microfuse memory device connects across the driver output lines, with n segments. Each segment is associated with one driver output line, and includes a microfuse that is blown when a signal appears on the associated driver output line.

  16. Remarks on the maximum luminosity

    Science.gov (United States)

    Cardoso, Vitor; Ikeda, Taishi; Moore, Christopher J.; Yoo, Chul-Moon

    2018-04-01

    The quest for fundamental limitations on physical processes is old and venerable. Here, we investigate the maximum possible power, or luminosity, that any event can produce. We show, via full nonlinear simulations of Einstein's equations, that there exist initial conditions which give rise to arbitrarily large luminosities. However, the requirement that there is no past horizon in the spacetime seems to limit the luminosity to below the Planck value, LP=c5/G . Numerical relativity simulations of critical collapse yield the largest luminosities observed to date, ≈ 0.2 LP . We also present an analytic solution to the Einstein equations which seems to give an unboundedly large luminosity; this will guide future numerical efforts to investigate super-Planckian luminosities.

  17. Maximum mutual information regularized classification

    KAUST Repository

    Wang, Jim Jing-Yan

    2014-09-07

    In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.

  18. Scintillation counter, maximum gamma aspect

    International Nuclear Information System (INIS)

    Thumim, A.D.

    1975-01-01

    A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into radiation-responsive areas. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (U.S.)

  19. Maximum mutual information regularized classification

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yi; Zhao, Shiguang; Gao, Xin

    2014-01-01

    In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.

  20. Three-Dimensional Normal Human Neutral Progenitor Tissue-Like Assemblies: A Model for Persistent Varicella-Zoster Virus Infection and Platform to Study Oxidate Stress and Damage in Multiple Hit Scenarios

    Science.gov (United States)

    Goodwin, Thomas J.; McCarthy, M.; Osterrieder, N.; Cohrs, R. J.; Kaufer, B. B.

    2014-01-01

    The environment of space results in a multitude of challenges to the human physiology that present barriers to extended habitation and exploration. Over 40 years of investigation to define countermeasures to address space flight adaptation has left gaps in our knowledge regarding mitigation strategies partly due to the lack of investigative tools, monitoring strategies, and real time diagnostics to understand the central causative agent(s) responsible for physiologic adaptation and maintaining homeostasis. Spaceflight-adaptation syndrome is the combination of space environmental conditions and the synergistic reaction of the human physiology. Our work addresses the role of oxidative stress and damage (OSaD) as a negative and contributing Risk Factor (RF) in the following areas of combined spaceflight related dysregulation: i) radiation induced cellular damage [1], [2] ii) immune impacts and the inflammatory response [3], [4] and iii) varicella zoster virus (VZV) reactivation [5]. Varicella-zoster (VZV)/Chicken Pox virus is a neurotropic human alphaherpes virus resulting in varicella upon primary infection, suppressed by the immune system becomes latent in ganglionic neurons, and reactivates under stress events to re-express in zoster and possibly shingles. Our laboratory has developed a complex three-dimensional (3D) normal human neural tissue model that emulates several characteristics of the human trigeminal ganglia (TG) and allows the study of combinatorial experimentation which addresses, simultaneously, OSaD associated with Spaceflight adaptation and habitation [6]. By combining the RFs of microgravity, radiation, and viral infection we will demonstrate that living in the space environment leads to significant physiological consequences for the peripheral and subsequently the central nervous system (PNS, CNS) associated with OSaD generation and consequentially endangers long-duration and exploration-class missions.

  1. Cadmium, cobalt and lead cause stress response, cell cycle deregulation and increased steroid as well as xenobiotic metabolism in primary normal human bronchial epithelial cells which is coordinated by at least nine transcription factors

    Energy Technology Data Exchange (ETDEWEB)

    Glahn, Felix; Wiese, Jan; Foth, Heidi [Martin-Luther-University, Halle-Wittenberg, Institute of Environmental Toxicology, Halle/Saale (Germany); Schmidt-Heck, Wolfgang; Guthke, Reinhard [Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena (Germany); Zellmer, Sebastian; Gebhardt, Rolf [University of Leipzig, Institute of Biochemistry, Medical Faculty, Leipzig (Germany); Golka, Klaus; Degen, Gisela H.; Hermes, Matthias; Schormann, Wiebke; Brulport, Marc; Bauer, Alexander; Bedawy, Essam [IfADo, Leibniz Research Centre for Working Environment and Human Factors, Dortmund (Germany); Hergenroeder, Roland [ISAS, Institute for Analytical Sciences, Dortmund (Germany); Lehmann, Thomas [Translational Centre for Regenerative Medicine, Leipzig (Germany); Hengstler, Jan G. [IfADo, Leibniz Research Centre for Working Environment and Human Factors, Dortmund (Germany)

    2008-08-15

    Workers occupationally exposed to cadmium, cobalt and lead have been reported to have increased levels of DNA damage. To analyze whether in vivo relevant concentrations of heavy metals cause systematic alterations in RNA expression patterns, we performed a gene array study using primary normal human bronchial epithelial cells. Cells were incubated with 15{mu}g/l Cd(II), 25{mu}g/l Co(II) and 550{mu}g/l Pb(II) either with individual substances or in combination. Differentially expressed genes were filtered out and used to identify enriched GO categories as well as KEGG pathways and to identify transcription factors whose binding sites are enriched in a given set of promoters. Interestingly, combined exposure to Cd(II), Co(II) and Pb(II) caused a coordinated response of at least seven stress response-related transcription factors, namely Oct-1, HIC1, TGIF, CREB, ATF4, SRF and YY1. A stress response was further corroborated by up regulation of genes involved in glutathione metabolism. A second major response to heavy metal exposure was deregulation of the cell cycle as evidenced by down regulation of the transcription factors ELK-1 and the Ets transcription factor GABP, as well as deregulation of genes involved in purine and pyrimidine metabolism. A third and surprising response was up regulation of genes involved in steroid metabolism, whereby promoter analysis identified up regulation of SRY that is known to play a role in sex determination. A forth response was up regulation of xenobiotic metabolising enzymes, particularly of dihydrodiol dehydrogenases 1 and 2 (AKR1C1, AKR1C2). Incubations with individual heavy metals showed that the response of AKR1C1 and AKR1C2 was predominantly caused by lead. In conclusion, we have shown that in vivo relevant concentrations of Cd(II), Co(II) and Pb(II) cause a complex and coordinated response in normal human bronchial epithelial cells. This study gives an overview of the most responsive genes. (orig.)

  2. Maximum spectral demands in the near-fault region

    Science.gov (United States)

    Huang, Yin-Nan; Whittaker, Andrew S.; Luco, Nicolas

    2008-01-01

    The Next Generation Attenuation (NGA) relationships for shallow crustal earthquakes in the western United States predict a rotated geometric mean of horizontal spectral demand, termed GMRotI50, and not maximum spectral demand. Differences between strike-normal, strike-parallel, geometric-mean, and maximum spectral demands in the near-fault region are investigated using 147 pairs of records selected from the NGA strong motion database. The selected records are for earthquakes with moment magnitude greater than 6.5 and for closest site-to-fault distance less than 15 km. Ratios of maximum spectral demand to NGA-predicted GMRotI50 for each pair of ground motions are presented. The ratio shows a clear dependence on period and the Somerville directivity parameters. Maximum demands can substantially exceed NGA-predicted GMRotI50 demands in the near-fault region, which has significant implications for seismic design, seismic performance assessment, and the next-generation seismic design maps. Strike-normal spectral demands are a significantly unconservative surrogate for maximum spectral demands for closest distance greater than 3 to 5 km. Scale factors that transform NGA-predicted GMRotI50 to a maximum spectral demand in the near-fault region are proposed.

  3. Comprehensive gene expression analysis of the NAC gene family under normal growth conditions, hormone treatment, and drought stress conditions in rice using near-isogenic lines (NILs) generated from crossing Aday Selection (drought tolerant) and IR64.

    Science.gov (United States)

    Nuruzzaman, Mohammed; Sharoni, Akhter Most; Satoh, Kouji; Moumeni, Ali; Venuprasad, Ramiah; Serraj, Rachid; Kumar, Arvind; Leung, Hei; Attia, Kotb; Kikuchi, Shoshi

    2012-05-01

    The NAC (NAM, ATAF1/2 and CUC2) genes are plant-specific transcriptional factors known to play diverse roles in various plant developmental processes. We describe the rice (Oryza sativa) OsNAC genes expression profiles (GEPs) under normal and water-deficit treatments (WDTs). The GEPs of the OsNAC genes were analyzed in 25 tissues covering the entire life cycle of Minghui 63. High expression levels of 17 genes were demonstrated in certain tissues under normal conditions suggesting that these genes may play important roles in specific organs. We determined that 16 genes were differentially expressed under at least 1 phytohormone (NAA, GA3, KT, SA, ABA, and JA) treatment. To investigate the GEPs in the root, leaf, and panicle of three rice genotypes [e.g., 2 near-isogenic lines (NILs) and IR64], we used two NILs from a common genetic combination backcross developed by Aday Selection and IR64. WDTs were applied using the fraction of transpirable soil water at severe, mild, and control conditions. Transcriptomic analysis using a 44K oligoarray from Agilent was performed on all the tissue samples. We identified common and specific genes in all tissues from the two NILs under both WDTs, and the majority of the OsNAC genes that were activated were in the drought-tolerant IR77298-14-1-2-B-10 line compared with the drought-susceptible IR77298-14-1-2-B-13 or IR64. In IR77298-14-1-2-B-10, seventeen genes were very specific in their expression levels. Approximately 70 % of the genes from subgroups SNAC and NAM/CUC3 were activated in the leaf, but 37 % genes from subgroup SND were inactivated in the root compared with the control under severe stress conditions. These results provide a useful reference for the cloning of candidate genes from the specific subgroup for further functional analysis.

  4. Photobiomodulation on Stress

    Directory of Open Access Journals (Sweden)

    Timon Cheng-Yi Liu

    2012-01-01

    Full Text Available Photobiomodulation (PBM is a nondamaged modulation of laser irradiation or monochromatic light (LI on a biosystem function. It depends on whether the function is in its function-specific homeostasis (FSH. An FSH is a negative-feedback response of a biosystem to maintain the function-specific conditions inside the biosystem so that the function is perfectly performed. A function in its FSH is called a normal function. A function far from its FSH is called a dysfunctional function. The process of a function from dysfunctional to normal is called a functional normalization. For a normal function in its FSH, there are FSH-essential subfunctions (FESs, FSH-nonessential subfunctions (FNSs, and an FES/FNS-specific homeostasis (FESH/FNSH. A FSH can resist internal/external disturbances under the threshold, but can be disrupted by an FSH-specific stress (FSS. A normal/dysfunctional FSS is called a successful/chronic stress. An FESH/FNSH-specific stress was called an extraordinary/ordinary stress. A low level LI (LLL cannot directly affect a normal function, but can modulate a chronic stress. A normal function may have a chronic ordinary stress, and an LLL may modulate the chronic ordinary stress so that it promotes the normalization of the dysfunctional FNS and then upgrades the normal function. A high level LI can modulate a normal function and may be a successful stress.

  5. Wavelength selection in injection-driven Hele-Shaw flows: A maximum amplitude criterion

    Science.gov (United States)

    Dias, Eduardo; Miranda, Jose

    2013-11-01

    As in most interfacial flow problems, the standard theoretical procedure to establish wavelength selection in the viscous fingering instability is to maximize the linear growth rate. However, there are important discrepancies between previous theoretical predictions and existing experimental data. In this work we perform a linear stability analysis of the radial Hele-Shaw flow system that takes into account the combined action of viscous normal stresses and wetting effects. Most importantly, we introduce an alternative selection criterion for which the selected wavelength is determined by the maximum of the interfacial perturbation amplitude. The effectiveness of such a criterion is substantiated by the significantly improved agreement between theory and experiments. We thank CNPq (Brazilian Sponsor) for financial support.

  6. Maximum likelihood estimation of finite mixture model for economic data

    Science.gov (United States)

    Phoong, Seuk-Yen; Ismail, Mohd Tahir

    2014-06-01

    Finite mixture model is a mixture model with finite-dimension. This models are provides a natural representation of heterogeneity in a finite number of latent classes. In addition, finite mixture models also known as latent class models or unsupervised learning models. Recently, maximum likelihood estimation fitted finite mixture models has greatly drawn statistician's attention. The main reason is because maximum likelihood estimation is a powerful statistical method which provides consistent findings as the sample sizes increases to infinity. Thus, the application of maximum likelihood estimation is used to fit finite mixture model in the present paper in order to explore the relationship between nonlinear economic data. In this paper, a two-component normal mixture model is fitted by maximum likelihood estimation in order to investigate the relationship among stock market price and rubber price for sampled countries. Results described that there is a negative effect among rubber price and stock market price for Malaysia, Thailand, Philippines and Indonesia.

  7. Maximum entropy and Bayesian methods

    International Nuclear Information System (INIS)

    Smith, C.R.; Erickson, G.J.; Neudorfer, P.O.

    1992-01-01

    Bayesian probability theory and Maximum Entropy methods are at the core of a new view of scientific inference. These 'new' ideas, along with the revolution in computational methods afforded by modern computers allow astronomers, electrical engineers, image processors of any type, NMR chemists and physicists, and anyone at all who has to deal with incomplete and noisy data, to take advantage of methods that, in the past, have been applied only in some areas of theoretical physics. The title workshops have been the focus of a group of researchers from many different fields, and this diversity is evident in this book. There are tutorial and theoretical papers, and applications in a very wide variety of fields. Almost any instance of dealing with incomplete and noisy data can be usefully treated by these methods, and many areas of theoretical research are being enhanced by the thoughtful application of Bayes' theorem. Contributions contained in this volume present a state-of-the-art overview that will be influential and useful for many years to come

  8. Stress distribution in two-dimensional silos

    Science.gov (United States)

    Blanco-Rodríguez, Rodolfo; Pérez-Ángel, Gabriel

    2018-01-01

    Simulations of a polydispersed two-dimensional silo were performed using molecular dynamics, with different numbers of grains reaching up to 64 000, verifying numerically the model derived by Janssen and also the main assumption that the walls carry part of the weight due to the static friction between grains with themselves and those with the silo's walls. We vary the friction coefficient, the radii dispersity, the silo width, and the size of grains. We find that the Janssen's model becomes less relevant as the the silo width increases since the behavior of the stresses becomes more hydrostatic. Likewise, we get the normal and tangential stress distribution on the walls evidencing the existence of points of maximum stress. We also obtained the stress matrix with which we observe zones of concentration of load, located always at a height around two thirds of the granular columns. Finally, we observe that the size of the grains affects the distribution of stresses, increasing the weight on the bottom and reducing the normal stress on the walls, as the grains are made smaller (for the same total mass of the granulate), giving again a more hydrostatic and therefore less Janssen-type behavior for the weight of the column.

  9. Normal Pressure Hydrocephalus (NPH)

    Science.gov (United States)

    ... local chapter Join our online community Normal Pressure Hydrocephalus (NPH) Normal pressure hydrocephalus is a brain disorder ... Symptoms Diagnosis Causes & risks Treatments About Normal Pressure Hydrocephalus Normal pressure hydrocephalus occurs when excess cerebrospinal fluid ...

  10. Maximum entropy principal for transportation

    International Nuclear Information System (INIS)

    Bilich, F.; Da Silva, R.

    2008-01-01

    In this work we deal with modeling of the transportation phenomenon for use in the transportation planning process and policy-impact studies. The model developed is based on the dependence concept, i.e., the notion that the probability of a trip starting at origin i is dependent on the probability of a trip ending at destination j given that the factors (such as travel time, cost, etc.) which affect travel between origin i and destination j assume some specific values. The derivation of the solution of the model employs the maximum entropy principle combining a priori multinomial distribution with a trip utility concept. This model is utilized to forecast trip distributions under a variety of policy changes and scenarios. The dependence coefficients are obtained from a regression equation where the functional form is derived based on conditional probability and perception of factors from experimental psychology. The dependence coefficients encode all the information that was previously encoded in the form of constraints. In addition, the dependence coefficients encode information that cannot be expressed in the form of constraints for practical reasons, namely, computational tractability. The equivalence between the standard formulation (i.e., objective function with constraints) and the dependence formulation (i.e., without constraints) is demonstrated. The parameters of the dependence-based trip-distribution model are estimated, and the model is also validated using commercial air travel data in the U.S. In addition, policy impact analyses (such as allowance of supersonic flights inside the U.S. and user surcharge at noise-impacted airports) on air travel are performed.

  11. Yield stress of alumina-zirconia suspensions

    International Nuclear Information System (INIS)

    Ramakrishnan, V.; Pradip; Malghan, S.G.

    1996-01-01

    The yield stress of concentrated suspensions of alumina, zirconia, and mixed alumina-zirconia powders was measured by the vane technique as a function of solids loading, relative amounts of alumina and zirconia, and pH. At the isoelectric point (IEP), the yield stress varied as the fourth power of the solids loading. The relative ratio of alumina and zirconia particles was important in determining the yield stress of the suspension at the IEP. The yield stress of single and mixed suspensions showed a marked variation with pH. The maximum value occurred at or near the IEP of the suspension. The effect of electrical double-layer forces on the yield stress can be described on the basis of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. A normalized yield stress--that is, the ratio of the yield stress at a given pH to the yield stress at the IEP predicted by this model--showed good correlation with experimental data

  12. U.S. Monthly Climate Normals (1971-2000)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — U.S. Monthly Climate Normals (1971-2000) (DSI-9641C) include climatological normals based on monthly maximum, minimum, and mean temperature and monthly total...

  13. Investigation of smooth specimen scc test procedures; variations in environment, specimen size, stressing frame, and stress state. [for high strength aluminum alloys

    Science.gov (United States)

    Lifka, B. W.; Sprowls, D. O.; Kelsey, R. A.

    1975-01-01

    The variables studied in the stress-corrosion cracking performance of high strength aluminum alloys were: (1) corrosiveness of the environment, (2) specimen size and stiffness of the stressing system, (3) interpretation of transgranular cracking, and (4) interaction of the state of stress and specimen orientation in a product with an anisotropic grain structure. It was shown that the probability of failure and time to fracture for a specimen loaded in direct tension are influenced by corrosion pattern, the stressing assembly stiffness, and the notch tensile strength of the alloy. Results demonstrate that the combination of a normal tension stress and a shear stress acting on the plane of maximum susceptibility in a product with a highly directional grain cause the greatest tendency for stress-corrosion cracking.

  14. The Effect of Intertia, Visocus Damping, Temperature and Normal ...

    Indian Academy of Sciences (India)

    29

    system. However, the present study has shown the appearance of chaos for specific values of normal stress before it disappears again as the normal stress varies further. It is also ... μ and v* are reference frictional shear stress and shear velocity corresponding to the AC laws ...... thesis Harvard University. Zhiren, N. and ...

  15. Anisotropic swim stress in active matter with nematic order

    Science.gov (United States)

    Yan, Wen; Brady, John F.

    2018-05-01

    Active Brownian particles (ABPs) transmit a swim pressure {{{\\Pi }}}{{swim}}=n\\zeta {D}{{swim}} to the container boundaries, where ζ is the drag coefficient, D swim is the swim diffusivity and n is the uniform bulk number density far from the container walls. In this work we extend the notion of the isotropic swim pressure to the anisotropic tensorial swim stress {{\\boldsymbol{σ }}}{{swim}}=-n\\zeta {{\\boldsymbol{D}}}{{swim}}, which is related to the anisotropic swim diffusivity {{\\boldsymbol{D}}}{{swim}}. We demonstrate this relationship with ABPs that achieve nematic orientational order via a bulk external field. The anisotropic swim stress is obtained analytically for dilute ABPs in both 2D and 3D systems. The anisotropy, defined as the ratio of the maximum to the minimum of the three principal stresses, is shown to grow exponentially with the strength of the external field. We verify that the normal component of the anisotropic swim stress applies a pressure {{{\\Pi }}}{{swim}}=-({{\\boldsymbol{σ }}}{{swim}}\\cdot {\\boldsymbol{n}})\\cdot {\\boldsymbol{n}} on a wall with normal vector {\\boldsymbol{n}}, and, through Brownian dynamics simulations, this pressure is shown to be the force per unit area transmitted by the active particles. Since ABPs have no friction with a wall, the difference between the normal and tangential stress components—the normal stress difference—generates a net flow of ABPs along the wall, which is a generic property of active matter systems.

  16. Last Glacial Maximum Salinity Reconstruction

    Science.gov (United States)

    Homola, K.; Spivack, A. J.

    2016-12-01

    It has been previously demonstrated that salinity can be reconstructed from sediment porewater. The goal of our study is to reconstruct high precision salinity during the Last Glacial Maximum (LGM). Salinity is usually determined at high precision via conductivity, which requires a larger volume of water than can be extracted from a sediment core, or via chloride titration, which yields lower than ideal precision. It has been demonstrated for water column samples that high precision density measurements can be used to determine salinity at the precision of a conductivity measurement using the equation of state of seawater. However, water column seawater has a relatively constant composition, in contrast to porewater, where variations from standard seawater composition occur. These deviations, which affect the equation of state, must be corrected for through precise measurements of each ion's concentration and knowledge of apparent partial molar density in seawater. We have developed a density-based method for determining porewater salinity that requires only 5 mL of sample, achieving density precisions of 10-6 g/mL. We have applied this method to porewater samples extracted from long cores collected along a N-S transect across the western North Atlantic (R/V Knorr cruise KN223). Density was determined to a precision of 2.3x10-6 g/mL, which translates to salinity uncertainty of 0.002 gms/kg if the effect of differences in composition is well constrained. Concentrations of anions (Cl-, and SO4-2) and cations (Na+, Mg+, Ca+2, and K+) were measured. To correct salinities at the precision required to unravel LGM Meridional Overturning Circulation, our ion precisions must be better than 0.1% for SO4-/Cl- and Mg+/Na+, and 0.4% for Ca+/Na+, and K+/Na+. Alkalinity, pH and Dissolved Inorganic Carbon of the porewater were determined to precisions better than 4% when ratioed to Cl-, and used to calculate HCO3-, and CO3-2. Apparent partial molar densities in seawater were

  17. Maximum Parsimony on Phylogenetic networks

    Science.gov (United States)

    2012-01-01

    Background Phylogenetic networks are generalizations of phylogenetic trees, that are used to model evolutionary events in various contexts. Several different methods and criteria have been introduced for reconstructing phylogenetic trees. Maximum Parsimony is a character-based approach that infers a phylogenetic tree by minimizing the total number of evolutionary steps required to explain a given set of data assigned on the leaves. Exact solutions for optimizing parsimony scores on phylogenetic trees have been introduced in the past. Results In this paper, we define the parsimony score on networks as the sum of the substitution costs along all the edges of the network; and show that certain well-known algorithms that calculate the optimum parsimony score on trees, such as Sankoff and Fitch algorithms extend naturally for networks, barring conflicting assignments at the reticulate vertices. We provide heuristics for finding the optimum parsimony scores on networks. Our algorithms can be applied for any cost matrix that may contain unequal substitution costs of transforming between different characters along different edges of the network. We analyzed this for experimental data on 10 leaves or fewer with at most 2 reticulations and found that for almost all networks, the bounds returned by the heuristics matched with the exhaustively determined optimum parsimony scores. Conclusion The parsimony score we define here does not directly reflect the cost of the best tree in the network that displays the evolution of the character. However, when searching for the most parsimonious network that describes a collection of characters, it becomes necessary to add additional cost considerations to prefer simpler structures, such as trees over networks. The parsimony score on a network that we describe here takes into account the substitution costs along the additional edges incident on each reticulate vertex, in addition to the substitution costs along the other edges which are

  18. Oxidative stress

    Directory of Open Access Journals (Sweden)

    Osredkar Joško

    2012-05-01

    Full Text Available The human organism is exposed to the influence of various forms of stress, either physical, psychological or chemical, which all have in common that they may adversely affect our body. A certain amount of stress is always present and somehow directs, promotes or inhibits the functioning of the human body. Unfortunately, we are now too many and too often exposed to excessive stress, which certainly has adverse consequences. This is especially true for a particular type of stress, called oxidative stress. All aerobic organisms are exposed to this type of stress because they produce energy by using oxygen. For this type of stress you could say that it is rather imperceptibly involved in our lives, as it becomes apparent only at the outbreak of certain diseases. Today we are well aware of the adverse impact of radicals, whose surplus is the main cause of oxidative stress. However, the key problem remains the detection of oxidative stress, which would allow us to undertake timely action and prevent outbreak of many diseases of our time. There are many factors that promote oxidative stress, among them are certainly a fast lifestyle and environmental pollution. The increase in oxidative stress can also trigger intense physical activity that is directly associated with an increased oxygen consumption and the resulting formation of free radicals. Considering generally positive attitude to physical activity, this fact may seem at first glance contradictory, but the finding has been confimed by several studies in active athletes. Training of a top athlete daily demands great physical effort, which is also reflected in the oxidative state of the organism. However, it should be noted that the top athletes in comparison with normal individuals have a different defense system, which can counteract the negative effects of oxidative stress. Quite the opposite is true for irregular or excessive physical activity to which the body is not adapted.

  19. Mammographic image restoration using maximum entropy deconvolution

    International Nuclear Information System (INIS)

    Jannetta, A; Jackson, J C; Kotre, C J; Birch, I P; Robson, K J; Padgett, R

    2004-01-01

    An image restoration approach based on a Bayesian maximum entropy method (MEM) has been applied to a radiological image deconvolution problem, that of reduction of geometric blurring in magnification mammography. The aim of the work is to demonstrate an improvement in image spatial resolution in realistic noisy radiological images with no associated penalty in terms of reduction in the signal-to-noise ratio perceived by the observer. Images of the TORMAM mammographic image quality phantom were recorded using the standard magnification settings of 1.8 magnification/fine focus and also at 1.8 magnification/broad focus and 3.0 magnification/fine focus; the latter two arrangements would normally give rise to unacceptable geometric blurring. Measured point-spread functions were used in conjunction with the MEM image processing to de-blur these images. The results are presented as comparative images of phantom test features and as observer scores for the raw and processed images. Visualization of high resolution features and the total image scores for the test phantom were improved by the application of the MEM processing. It is argued that this successful demonstration of image de-blurring in noisy radiological images offers the possibility of weakening the link between focal spot size and geometric blurring in radiology, thus opening up new approaches to system optimization

  20. Maximum power flux of auroral kilometric radiation

    International Nuclear Information System (INIS)

    Benson, R.F.; Fainberg, J.

    1991-01-01

    The maximum auroral kilometric radiation (AKR) power flux observed by distant satellites has been increased by more than a factor of 10 from previously reported values. This increase has been achieved by a new data selection criterion and a new analysis of antenna spin modulated signals received by the radio astronomy instrument on ISEE 3. The method relies on selecting AKR events containing signals in the highest-frequency channel (1980, kHz), followed by a careful analysis that effectively increased the instrumental dynamic range by more than 20 dB by making use of the spacecraft antenna gain diagram during a spacecraft rotation. This analysis has allowed the separation of real signals from those created in the receiver by overloading. Many signals having the appearance of AKR harmonic signals were shown to be of spurious origin. During one event, however, real second harmonic AKR signals were detected even though the spacecraft was at a great distance (17 R E ) from Earth. During another event, when the spacecraft was at the orbital distance of the Moon and on the morning side of Earth, the power flux of fundamental AKR was greater than 3 x 10 -13 W m -2 Hz -1 at 360 kHz normalized to a radial distance r of 25 R E assuming the power falls off as r -2 . A comparison of these intense signal levels with the most intense source region values (obtained by ISIS 1 and Viking) suggests that multiple sources were observed by ISEE 3

  1. The Benefits of Leisure Stress.

    Science.gov (United States)

    Mitchell, Jr., Richard G.

    1982-01-01

    Leisure bereft of all stress is action without purpose. Maximum motivation and gratification are achieved when a balance is achieved between abilities and responsibilities. Stress is an essential leisure ingredient that provides meaning and clarity to social experience. (CJ)

  2. Normalization: A Preprocessing Stage

    OpenAIRE

    Patro, S. Gopal Krishna; Sahu, Kishore Kumar

    2015-01-01

    As we know that the normalization is a pre-processing stage of any type problem statement. Especially normalization takes important role in the field of soft computing, cloud computing etc. for manipulation of data like scale down or scale up the range of data before it becomes used for further stage. There are so many normalization techniques are there namely Min-Max normalization, Z-score normalization and Decimal scaling normalization. So by referring these normalization techniques we are ...

  3. Optimization of Bolt Stress

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2013-01-01

    The state of stress in bolts and nuts with ISO metric thread design is examined and optimized. The assumed failure mode is fatigue so the applied preload and the load amplitude together with the stress concentrations define the connection strength. Maximum stress in the bolt is found at, the fillet...... under the head, at the thread start or at the thread root. To minimize the stress concentration shape optimization is applied....

  4. Two-dimensional maximum entropy image restoration

    International Nuclear Information System (INIS)

    Brolley, J.E.; Lazarus, R.B.; Suydam, B.R.; Trussell, H.J.

    1977-07-01

    An optical check problem was constructed to test P LOG P maximum entropy restoration of an extremely distorted image. Useful recovery of the original image was obtained. Comparison with maximum a posteriori restoration is made. 7 figures

  5. Normal Stresses and Interface Displacement: Influence of Viscoelasticity on Enhanced Oil Recovery Efficiency Contraintes normales et déplacement d’interface : influence de la viscoélasticité sur l’efficacité de la récupération assistée

    Directory of Open Access Journals (Sweden)

    Avendano J.

    2013-01-01

    Full Text Available One of chemical Enhanced Oil Recovery (EOR methods consists in injecting aqueous solutions of polymers into the reservoir in order to improve mobility ratio between the injected fluid and the remaining oil. This “polymer flooding” process is usually only characterized with the low shear viscosity of the injected fluid, even if these aqueous solutions are strongly shear thinning and may show high elastic properties evidenced by normal stresses appearance. In order to study the mechanisms at the interface level, we develop simple model experimentations with the goal of quantifying the influence of viscoelastic properties on fluid displacement in a simple geometry. For this purpose, we propose and characterize a model fluid formulation, for which elastic and viscous effects can be tuned systematically. We study then the displacement of a viscous oil by a Newtonian non elastic, a viscoelastic or a purely shear thinning fluid in a two dimensional flow cell. Observing the shape of the interface between aqueous fluids and displaced oil permits to appreciate viscoelasticity effects on the displacement. Using model geometries and controlled rheology fluids, we show that viscoelastic fluids tend to better displace immiscible liquids than Newtonian fluids and that those effects are closely related to the apparitions of normal stresses independently of shear thinning property or variation of interfacial tension as soon as viscous effects govern the flow. Une des méthodes de récupération assistée du pétrole (EOR - Enhanced Oil Recovery consiste à injecter dans les puits des solutions aqueuses de polymère pour améliorer le rapport de mobilité entre le fluide injecté et le pétrole qui reste dans le puits. Ce procédé de “polymer flooding” est communément caractérisé par la seule valeur de la viscosité à faible gradient de vitesse du fluide injecté, bien que les solutions employées présentent une forte rhéofluidification et

  6. What controls the maximum magnitude of injection-induced earthquakes?

    Science.gov (United States)

    Eaton, D. W. S.

    2017-12-01

    Three different approaches for estimation of maximum magnitude are considered here, along with their implications for managing risk. The first approach is based on a deterministic limit for seismic moment proposed by McGarr (1976), which was originally designed for application to mining-induced seismicity. This approach has since been reformulated for earthquakes induced by fluid injection (McGarr, 2014). In essence, this method assumes that the upper limit for seismic moment release is constrained by the pressure-induced stress change. A deterministic limit is given by the product of shear modulus and the net injected fluid volume. This method is based on the assumptions that the medium is fully saturated and in a state of incipient failure. An alternative geometrical approach was proposed by Shapiro et al. (2011), who postulated that the rupture area for an induced earthquake falls entirely within the stimulated volume. This assumption reduces the maximum-magnitude problem to one of estimating the largest potential slip surface area within a given stimulated volume. Finally, van der Elst et al. (2016) proposed that the maximum observed magnitude, statistically speaking, is the expected maximum value for a finite sample drawn from an unbounded Gutenberg-Richter distribution. These three models imply different approaches for risk management. The deterministic method proposed by McGarr (2014) implies that a ceiling on the maximum magnitude can be imposed by limiting the net injected volume, whereas the approach developed by Shapiro et al. (2011) implies that the time-dependent maximum magnitude is governed by the spatial size of the microseismic event cloud. Finally, the sample-size hypothesis of Van der Elst et al. (2016) implies that the best available estimate of the maximum magnitude is based upon observed seismicity rate. The latter two approaches suggest that real-time monitoring is essential for effective management of risk. A reliable estimate of maximum

  7. Receiver function estimated by maximum entropy deconvolution

    Institute of Scientific and Technical Information of China (English)

    吴庆举; 田小波; 张乃铃; 李卫平; 曾融生

    2003-01-01

    Maximum entropy deconvolution is presented to estimate receiver function, with the maximum entropy as the rule to determine auto-correlation and cross-correlation functions. The Toeplitz equation and Levinson algorithm are used to calculate the iterative formula of error-predicting filter, and receiver function is then estimated. During extrapolation, reflective coefficient is always less than 1, which keeps maximum entropy deconvolution stable. The maximum entropy of the data outside window increases the resolution of receiver function. Both synthetic and real seismograms show that maximum entropy deconvolution is an effective method to measure receiver function in time-domain.

  8. Maximum Power from a Solar Panel

    Directory of Open Access Journals (Sweden)

    Michael Miller

    2010-01-01

    Full Text Available Solar energy has become a promising alternative to conventional fossil fuel sources. Solar panels are used to collect solar radiation and convert it into electricity. One of the techniques used to maximize the effectiveness of this energy alternative is to maximize the power output of the solar collector. In this project the maximum power is calculated by determining the voltage and the current of maximum power. These quantities are determined by finding the maximum value for the equation for power using differentiation. After the maximum values are found for each time of day, each individual quantity, voltage of maximum power, current of maximum power, and maximum power is plotted as a function of the time of day.

  9. Ultrasonographic features of normal lower ureters

    International Nuclear Information System (INIS)

    Kim, Young Soon; Bae, M. Y.; Park, K. J.; Jeon, H. S.; Lee, J. H.

    1990-01-01

    Although ultrasonographic evaluation of the normal ureters is difficult due to bowel gas, the lower segment of the normal ureters can be visualized using the urinary bladder as an acoustic window. Authors prospetively performed ultrasonography with the standard suprapubic technique and analyzed the ultrasonographic features of normal lower ureters in 79 cases(77%). Length of visualized segment of the distal ureter ranged frp, 1.5cm to 7.2 cm and the visualized segment did not exceed 3.9mm in maximum diameter. Knowledge of sonographic features of the normal lower ureters can be helpful in the evaluation of pathologic or suspected pathologic conditions of the lower ureters

  10. Cyclic fatigue of near-isotopic graphite: influence of stress cycle and neutron irradiation

    International Nuclear Information System (INIS)

    Price, R.J.

    1977-11-01

    Near-isotropic graphites H-451 and PGX were tested in uniaxial cyclic fatigue, and fatigue life (S-N) curves were generated to a maximum of 10 5 cycles. The stress ratio, R (minimum stress during a cycle divided by maximum stress) ranged from -1 to +0.5. With R = - 1, the homologous stress limits (maximum applied fatigue stress divided by the tensile strength) for 50% specimen survival to 10 5 cycles averaged 0.63 in the axial direction and 0.74 in the radial direction. Corresponding homologous stress limits for 99% specimen survival (99/95 tolerance limits) were 0.48 and 0.53. Higher R-values resulted in longer fatigue lives and increased stress limits. H-451 graphite specimens irradiated with fast neutrons at 1173 to 1263 0 K at fluences of up to 10 26 n/m 2 (equivalent fission fluence) showed fatigue stress limits of about twice the unirradiated levels when the unirradiated tensile strength was used as the basis for normalization

  11. A locally adaptive normal distribution

    DEFF Research Database (Denmark)

    Arvanitidis, Georgios; Hansen, Lars Kai; Hauberg, Søren

    2016-01-01

    entropy distribution under the given metric. The underlying metric is, however, non-parametric. We develop a maximum likelihood algorithm to infer the distribution parameters that relies on a combination of gradient descent and Monte Carlo integration. We further extend the LAND to mixture models......The multivariate normal density is a monotonic function of the distance to the mean, and its ellipsoidal shape is due to the underlying Euclidean metric. We suggest to replace this metric with a locally adaptive, smoothly changing (Riemannian) metric that favors regions of high local density...

  12. Maximum permissible voltage of YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z. [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Hong, Z., E-mail: zhiyong.hong@sjtu.edu.cn [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Wang, D.; Zhou, H.; Shen, X.; Shen, C. [Qingpu Power Supply Company, State Grid Shanghai Municipal Electric Power Company, Shanghai (China)

    2014-06-15

    Highlights: • We examine three kinds of tapes’ maximum permissible voltage. • We examine the relationship between quenching duration and maximum permissible voltage. • Continuous I{sub c} degradations under repetitive quenching where tapes reaching maximum permissible voltage. • The relationship between maximum permissible voltage and resistance, temperature. - Abstract: Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (I{sub c}) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the I{sub c} degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  13. Effect of pertussis toxin pretreated centrally on blood glucose level induced by stress.

    Science.gov (United States)

    Suh, Hong-Won; Sim, Yun-Beom; Park, Soo-Hyun; Sharma, Naveen; Im, Hyun-Ju; Hong, Jae-Seung

    2016-09-01

    In the present study, we examined the effect of pertussis toxin (PTX) administered centrally in a variety of stress-induced blood glucose level. Mice were exposed to stress after the pretreatment of PTX (0.05 or 0.1 µg) i.c.v. or i.t. once for 6 days. Blood glucose level was measured at 0, 30, 60 and 120 min after stress stimulation. The blood glucose level was increased in all stress groups. The blood glucose level reached at maximum level after 30 min of stress stimulation and returned to a normal level after 2 h of stress stimulation in restraint stress, physical, and emotional stress groups. The blood glucose level induced by cold-water swimming stress was gradually increased up to 1 h and returned to the normal level. The intracerebroventricular (i.c.v.) or intrathecal (i.t.) pretreatment with PTX, a Gi inhibitor, alone produced a hypoglycemia and almost abolished the elevation of the blood level induced by stress stimulation. The central pretreatment with PTX caused a reduction of plasma insulin level, whereas plasma corticosterone level was further up-regulated in all stress models. Our results suggest that the hyperglycemia produced by physical stress, emotional stress, restraint stress, and the cold-water swimming stress appear to be mediated by activation of centrally located PTX-sensitive G proteins. The reduction of blood glucose level by PTX appears to due to the reduction of plasma insulin level. The reduction of blood glucose level by PTX was accompanied by the reduction of plasma insulin level. Plasma corticosterone level up-regulation by PTX in stress models may be due to a blood glucose homeostatic mechanism.

  14. Normalized modes at selected points without normalization

    Science.gov (United States)

    Kausel, Eduardo

    2018-04-01

    As every textbook on linear algebra demonstrates, the eigenvectors for the general eigenvalue problem | K - λM | = 0 involving two real, symmetric, positive definite matrices K , M satisfy some well-defined orthogonality conditions. Equally well-known is the fact that those eigenvectors can be normalized so that their modal mass μ =ϕT Mϕ is unity: it suffices to divide each unscaled mode by the square root of the modal mass. Thus, the normalization is the result of an explicit calculation applied to the modes after they were obtained by some means. However, we show herein that the normalized modes are not merely convenient forms of scaling, but that they are actually intrinsic properties of the pair of matrices K , M, that is, the matrices already "know" about normalization even before the modes have been obtained. This means that we can obtain individual components of the normalized modes directly from the eigenvalue problem, and without needing to obtain either all of the modes or for that matter, any one complete mode. These results are achieved by means of the residue theorem of operational calculus, a finding that is rather remarkable inasmuch as the residues themselves do not make use of any orthogonality conditions or normalization in the first place. It appears that this obscure property connecting the general eigenvalue problem of modal analysis with the residue theorem of operational calculus may have been overlooked up until now, but which has in turn interesting theoretical implications.Á

  15. Revealing the Maximum Strength in Nanotwinned Copper

    DEFF Research Database (Denmark)

    Lu, L.; Chen, X.; Huang, Xiaoxu

    2009-01-01

    boundary–related processes. We investigated the maximum strength of nanotwinned copper samples with different twin thicknesses. We found that the strength increases with decreasing twin thickness, reaching a maximum at 15 nanometers, followed by a softening at smaller values that is accompanied by enhanced...

  16. Modelling maximum canopy conductance and transpiration in ...

    African Journals Online (AJOL)

    There is much current interest in predicting the maximum amount of water that can be transpired by Eucalyptus trees. It is possible that industrial waste water may be applied as irrigation water to eucalypts and it is important to predict the maximum transpiration rates of these plantations in an attempt to dispose of this ...

  17. Gravity-driven groundwater flow and slope failure potential: 1. Elastic effective-stress model

    Science.gov (United States)

    Iverson, Richard M.; Reid, Mark E.

    1992-01-01

    Hilly or mountainous topography influences gravity-driven groundwater flow and the consequent distribution of effective stress in shallow subsurface environments. Effective stress, in turn, influences the potential for slope failure. To evaluate these influences, we formulate a two-dimensional, steady state, poroelastic model. The governing equations incorporate groundwater effects as body forces, and they demonstrate that spatially uniform pore pressure changes do not influence effective stresses. We implement the model using two finite element codes. As an illustrative case, we calculate the groundwater flow field, total body force field, and effective stress field in a straight, homogeneous hillslope. The total body force and effective stress fields show that groundwater flow can influence shear stresses as well as effective normal stresses. In most parts of the hillslope, groundwater flow significantly increases the Coulomb failure potential Φ, which we define as the ratio of maximum shear stress to mean effective normal stress. Groundwater flow also shifts the locus of greatest failure potential toward the slope toe. However, the effects of groundwater flow on failure potential are less pronounced than might be anticipated on the basis of a simpler, one-dimensional, limit equilibrium analysis. This is a consequence of continuity, compatibility, and boundary constraints on the two-dimensional flow and stress fields, and it points to important differences between our elastic continuum model and limit equilibrium models commonly used to assess slope stability.

  18. Determination of in-situ rock stresses related to petroleum activities on the Norwegian Continental Shelf

    Energy Technology Data Exchange (ETDEWEB)

    Fejerskov, Morten

    1996-12-31

    In-situ rock stresses have proved to be important for exploration and production of hydrocarbons. This thesis uses various stress determination techniques to characterize the in-situ stress field on the Norwegian Continental Shelf. Leak off tests and borehole breakouts have been used to determine the in-situ stress in deep well bores. Overcoring and earthquake focal mechanisms data have also been compiled and evaluated together with stress information from petroleum wells. A new test procedure is suggested to improve the quality of leak off tests that emphasises the importance of accurate pressure determination, longer test periods and digital data sampling. Four-arm calliper logs are used to identify borehole breakouts on the Tampen Spur and Horda Platform. However, it proved difficult to distinguish borehole breakouts from other drilling processes since the elongations of the borehole consistently appeared in the direction of hole azimuth; drilling-induced key seats are here observed in vertical wells. This behaviour is discussed but not fully understood. This reduces the number of reliable stress data and their quality enormously and even casts some doubt about the quality of previous breakout studies from the North Sea. A highly compressive horizontal stress field seems to be present onshore and offshore Norway. Different stress determination techniques yield very consistent stress orientation, regional and internal variation. A 1. order stress direction is identified, where the maximum horizontal stress direction is rotating from N-S in the Barents Sea to NW-SE in the Norwegian Sea and WNW-ESE in the northern North Sea. At Tampen Spur, a dominant WNW-ESE maximum horizontal stress direction, normal to the major tectonic structures is identified as well as a minimum stress close to the vertical stress, the latter indicating high horizontal stresses. 250 refs., 91 figs., 14 tabs.

  19. Investigating the Influence of Regional Stress on Fault and Fracture Permeability at Pahute Mesa, Nevada National Security Site

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Donald M. [Desert Research Inst. (DRI), Reno, NV (United States); Smith, Kenneth D. [Univ. of Nevada, Reno, NV (United States); Parashar, Rishi [Desert Research Inst. (DRI), Reno, NV (United States); Collins, Cheryl [Desert Research Inst. (DRI), Las Vegas, NV (United States); Heintz, Kevin M. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

    2017-05-24

    Regional stress may exert considerable control on the permeability and hydraulic function (i.e., barrier to and/or conduit for fluid flow) of faults and fractures at Pahute Mesa, Nevada National Security Site (NNSS). In-situ measurements of the stress field are sparse in this area, and short period earthquake focal mechanisms are used to delineate principal horizontal stress orientations. Stress field inversion solutions to earthquake focal mechanisms indicate that Pahute Mesa is located within a transtensional faulting regime, represented by oblique slip on steeply dipping normal fault structures, with maximum horizontal stress ranging from N29°E to N63°E and average of N42°E. Average horizontal stress directions are in general agreement with large diameter borehole breakouts from Pahute Mesa analyzed in this study and with stress measurements from other locations on the NNSS.

  20. Normal foot and ankle

    International Nuclear Information System (INIS)

    Weissman, S.D.

    1989-01-01

    The foot may be thought of as a bag of bones tied tightly together and functioning as a unit. The bones re expected to maintain their alignment without causing symptomatology to the patient. The author discusses a normal radiograph. The bones must have normal shape and normal alignment. The density of the soft tissues should be normal and there should be no fractures, tumors, or foreign bodies

  1. MXLKID: a maximum likelihood parameter identifier

    International Nuclear Information System (INIS)

    Gavel, D.T.

    1980-07-01

    MXLKID (MaXimum LiKelihood IDentifier) is a computer program designed to identify unknown parameters in a nonlinear dynamic system. Using noisy measurement data from the system, the maximum likelihood identifier computes a likelihood function (LF). Identification of system parameters is accomplished by maximizing the LF with respect to the parameters. The main body of this report briefly summarizes the maximum likelihood technique and gives instructions and examples for running the MXLKID program. MXLKID is implemented LRLTRAN on the CDC7600 computer at LLNL. A detailed mathematical description of the algorithm is given in the appendices. 24 figures, 6 tables

  2. On the maximum of wave surface of sea waves

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, B

    1980-01-01

    This article considers wave surface as a normal stationary random process to solve the estimation of the maximum of wave surface in a given time interval by means of the theoretical results of probability theory. The results are represented by formulas (13) to (19) in this article. It was proved in this article that when time interval approaches infinite, the formulas (3), (6) of E )eta max) that were derived from the references (Cartwright, Longuet-Higgins) can also be derived by asymptotic distribution of the maximum of wave surface provided by the article. The advantage of the results obtained from this point of view as compared with the results obtained from the references was discussed.

  3. Maximum neutron flux in thermal reactors

    International Nuclear Information System (INIS)

    Strugar, P.V.

    1968-12-01

    Direct approach to the problem is to calculate spatial distribution of fuel concentration if the reactor core directly using the condition of maximum neutron flux and comply with thermal limitations. This paper proved that the problem can be solved by applying the variational calculus, i.e. by using the maximum principle of Pontryagin. Mathematical model of reactor core is based on the two-group neutron diffusion theory with some simplifications which make it appropriate from maximum principle point of view. Here applied theory of maximum principle are suitable for application. The solution of optimum distribution of fuel concentration in the reactor core is obtained in explicit analytical form. The reactor critical dimensions are roots of a system of nonlinear equations and verification of optimum conditions can be done only for specific examples

  4. Maximum allowable load on wheeled mobile manipulators

    International Nuclear Information System (INIS)

    Habibnejad Korayem, M.; Ghariblu, H.

    2003-01-01

    This paper develops a computational technique for finding the maximum allowable load of mobile manipulator during a given trajectory. The maximum allowable loads which can be achieved by a mobile manipulator during a given trajectory are limited by the number of factors; probably the dynamic properties of mobile base and mounted manipulator, their actuator limitations and additional constraints applied to resolving the redundancy are the most important factors. To resolve extra D.O.F introduced by the base mobility, additional constraint functions are proposed directly in the task space of mobile manipulator. Finally, in two numerical examples involving a two-link planar manipulator mounted on a differentially driven mobile base, application of the method to determining maximum allowable load is verified. The simulation results demonstrates the maximum allowable load on a desired trajectory has not a unique value and directly depends on the additional constraint functions which applies to resolve the motion redundancy

  5. Maximum phytoplankton concentrations in the sea

    DEFF Research Database (Denmark)

    Jackson, G.A.; Kiørboe, Thomas

    2008-01-01

    A simplification of plankton dynamics using coagulation theory provides predictions of the maximum algal concentration sustainable in aquatic systems. These predictions have previously been tested successfully against results from iron fertilization experiments. We extend the test to data collect...

  6. Maximum-Likelihood Detection Of Noncoherent CPM

    Science.gov (United States)

    Divsalar, Dariush; Simon, Marvin K.

    1993-01-01

    Simplified detectors proposed for use in maximum-likelihood-sequence detection of symbols in alphabet of size M transmitted by uncoded, full-response continuous phase modulation over radio channel with additive white Gaussian noise. Structures of receivers derived from particular interpretation of maximum-likelihood metrics. Receivers include front ends, structures of which depends only on M, analogous to those in receivers of coherent CPM. Parts of receivers following front ends have structures, complexity of which would depend on N.

  7. The spectrum of R Cygni during its exceptionally low maximum of 1983

    International Nuclear Information System (INIS)

    Wallerstein, G.; Dominy, J.F.; Mattei, J.A.; Smith, V.V.

    1985-01-01

    In 1983 R Cygni experienced its faintest maximum ever recorded. A study of the light curve shows correlations between brightness at maximum and interval from the previous cycle, in the sense that fainter maxima occur later than normal and are followed by maxima that occur earlier than normal. Emission and absorption lines in the optical and near infrared (2.2 μm region) reveal two significant correlations. The amplitude of line doubling is independent of the magnitude at maximum for msub(v)(max)=7.1 to 9.8. The velocities of the emission lines, however, correlate with the magnitude at maximum, in that during bright maxima they are negatively displaced by 15 km s -1 with respect to the red component of absorption lines, while during the faintest maximum there is no displacement. (author)

  8. The stress characteristics of plate-fin structures at the different operation parameters of LNG heat exchanger

    Directory of Open Access Journals (Sweden)

    Ma Hongqiang

    2018-01-01

    Full Text Available In this paper, the stresses of plate-fin structures at the different operation parameters were analyzed in actual operation process of LNG plate-fin heat exchanger based on finite element method and thermal elastic theory. Stress characteristics of plate-fin structures were investigated at the different operation parameters of that. The results show that the structural failure of plate-fin structures is mainly induced by the maximum shear stress at the brazing filler metal layer between plate and fin while by the maximum normal stress in the region of brazed joint near the fin side. And a crack would initiate in brazed joint near the fin side. The maximum normal stress is also main factor to result in the structural failure of plate-fin structures at the different temperature difference (between Natural Gas (NG and Mixture Refrigerant (MR, MR temperature and NG pressure of LNG heat exchanger. At the same time, the peak stresses obviously increase as the temperature difference, MR temperature and NG pressure increase. These results will provide some constructive instructions in the safe operation of LNG plate-fin heat exchanger in a large-scale LNG cold-box.

  9. Maximum gravitational redshift of white dwarfs

    International Nuclear Information System (INIS)

    Shapiro, S.L.; Teukolsky, S.A.

    1976-01-01

    The stability of uniformly rotating, cold white dwarfs is examined in the framework of the Parametrized Post-Newtonian (PPN) formalism of Will and Nordtvedt. The maximum central density and gravitational redshift of a white dwarf are determined as functions of five of the nine PPN parameters (γ, β, zeta 2 , zeta 3 , and zeta 4 ), the total angular momentum J, and the composition of the star. General relativity predicts that the maximum redshifts is 571 km s -1 for nonrotating carbon and helium dwarfs, but is lower for stars composed of heavier nuclei. Uniform rotation can increase the maximum redshift to 647 km s -1 for carbon stars (the neutronization limit) and to 893 km s -1 for helium stars (the uniform rotation limit). The redshift distribution of a larger sample of white dwarfs may help determine the composition of their cores

  10. a Recursive Approach to Compute Normal Forms

    Science.gov (United States)

    HSU, L.; MIN, L. J.; FAVRETTO, L.

    2001-06-01

    Normal forms are instrumental in the analysis of dynamical systems described by ordinary differential equations, particularly when singularities close to a bifurcation are to be characterized. However, the computation of a normal form up to an arbitrary order is numerically hard. This paper focuses on the computer programming of some recursive formulas developed earlier to compute higher order normal forms. A computer program to reduce the system to its normal form on a center manifold is developed using the Maple symbolic language. However, it should be stressed that the program relies essentially on recursive numerical computations, while symbolic calculations are used only for minor tasks. Some strategies are proposed to save computation time. Examples are presented to illustrate the application of the program to obtain high order normalization or to handle systems with large dimension.

  11. The evolution of crack-tip stresses during a fatigue overload event

    International Nuclear Information System (INIS)

    Steuwer, A.; Rahman, M.; Shterenlikht, A.; Fitzpatrick, M.E.; Edwards, L.; Withers, P.J.

    2010-01-01

    The mechanisms responsible for the transient retardation or acceleration of fatigue crack growth subsequent to overloading are a matter of intense debate. Plasticity-induced closure and residual stresses have often been invoked to explain these phenomena, but closure mechanisms are disputed, especially under conditions approximating to generalised plane strain. In this paper we exploit synchrotron radiation to report very high spatial resolution two-dimensional elastic strain and stress maps at maximum and minimum loading measured under plane strain during a normal fatigue cycle, as well as during and after a 100% overload event, in ultra-fine grained AA5091 aluminium alloy. These observations provide direct evidence of the material stress state in the vicinity of the crack-tip in thick samples. Significant compressive residual stresses were found both in front of and behind the crack-tip immediately following the overload event. The effective stress intensity at the crack-tip was determined directly from the local stress field measured deep within the bulk (plane strain) by comparison with linear elastic fracture mechanical theory. This agrees well with that nominally applied at maximum load and 100% overload. After overload, however, the stress fields were not well described by classical K fields due to closure-related residual stresses. Little evidence of overload closure was observed sometime after the overload event, in our case possibly because the overload plastic zone was very small.

  12. Infrared thermometry and the crop water stress index. I. History, theory, and baselines

    International Nuclear Information System (INIS)

    Gardner, B.R.; Nielsen, D.C.; Shock, C.C.

    1992-01-01

    Development of portable infrared thermometers and the definition of the Crop Water Stress Index (CWSI) have led to widespread interest in infrared thermometry to monitor water stress and schedule irrigations. But the CWSI concept is still new and poorly understood by many. The purpose of this paper is to review the definition of CWSI, and the determination and interpretation of the non-water-stressed baselines used to compute CWSI. The non-water-stressed baseline equation normalizes the canopy minus air temperature differential for variations in vapor pressure deficit. Non-water-stressed baselines can be determined empirically from measurements of canopy and air temperatures and vapor pressure deficit, made diurnally on a single day, or at a single time of day over many days, on well-watered plants. The value of the maximum canopy minus air temperature differential under maximum water stress should also be determined empirically. Causes for CWSI values falling outside of the defined 0 to 10 unit range are reviewed. Non-water-stressed baselines may shift with plant growth stage. Effective use of CWSI is dependent on understanding the definition of CWSI, and the proper determination and use of non-water-stressed baselines. (author)

  13. Maximum entropy analysis of EGRET data

    DEFF Research Database (Denmark)

    Pohl, M.; Strong, A.W.

    1997-01-01

    EGRET data are usually analysed on the basis of the Maximum-Likelihood method \\cite{ma96} in a search for point sources in excess to a model for the background radiation (e.g. \\cite{hu97}). This method depends strongly on the quality of the background model, and thus may have high systematic unce...... uncertainties in region of strong and uncertain background like the Galactic Center region. Here we show images of such regions obtained by the quantified Maximum-Entropy method. We also discuss a possible further use of MEM in the analysis of problematic regions of the sky....

  14. The Maximum Resource Bin Packing Problem

    DEFF Research Database (Denmark)

    Boyar, J.; Epstein, L.; Favrholdt, L.M.

    2006-01-01

    Usually, for bin packing problems, we try to minimize the number of bins used or in the case of the dual bin packing problem, maximize the number or total size of accepted items. This paper presents results for the opposite problems, where we would like to maximize the number of bins used...... algorithms, First-Fit-Increasing and First-Fit-Decreasing for the maximum resource variant of classical bin packing. For the on-line variant, we define maximum resource variants of classical and dual bin packing. For dual bin packing, no on-line algorithm is competitive. For classical bin packing, we find...

  15. Shower maximum detector for SDC calorimetry

    International Nuclear Information System (INIS)

    Ernwein, J.

    1994-01-01

    A prototype for the SDC end-cap (EM) calorimeter complete with a pre-shower and a shower maximum detector was tested in beams of electrons and Π's at CERN by an SDC subsystem group. The prototype was manufactured from scintillator tiles and strips read out with 1 mm diameter wave-length shifting fibers. The design and construction of the shower maximum detector is described, and results of laboratory tests on light yield and performance of the scintillator-fiber system are given. Preliminary results on energy and position measurements with the shower max detector in the test beam are shown. (authors). 4 refs., 5 figs

  16. Topics in Bayesian statistics and maximum entropy

    International Nuclear Information System (INIS)

    Mutihac, R.; Cicuttin, A.; Cerdeira, A.; Stanciulescu, C.

    1998-12-01

    Notions of Bayesian decision theory and maximum entropy methods are reviewed with particular emphasis on probabilistic inference and Bayesian modeling. The axiomatic approach is considered as the best justification of Bayesian analysis and maximum entropy principle applied in natural sciences. Particular emphasis is put on solving the inverse problem in digital image restoration and Bayesian modeling of neural networks. Further topics addressed briefly include language modeling, neutron scattering, multiuser detection and channel equalization in digital communications, genetic information, and Bayesian court decision-making. (author)

  17. Baby Poop: What's Normal?

    Science.gov (United States)

    ... I'm breast-feeding my newborn and her bowel movements are yellow and mushy. Is this normal for baby poop? Answers from Jay L. Hoecker, M.D. Yellow, mushy bowel movements are perfectly normal for breast-fed babies. Still, ...

  18. Visual Memories Bypass Normalization.

    Science.gov (United States)

    Bloem, Ilona M; Watanabe, Yurika L; Kibbe, Melissa M; Ling, Sam

    2018-05-01

    How distinct are visual memory representations from visual perception? Although evidence suggests that briefly remembered stimuli are represented within early visual cortices, the degree to which these memory traces resemble true visual representations remains something of a mystery. Here, we tested whether both visual memory and perception succumb to a seemingly ubiquitous neural computation: normalization. Observers were asked to remember the contrast of visual stimuli, which were pitted against each other to promote normalization either in perception or in visual memory. Our results revealed robust normalization between visual representations in perception, yet no signature of normalization occurring between working memory stores-neither between representations in memory nor between memory representations and visual inputs. These results provide unique insight into the nature of visual memory representations, illustrating that visual memory representations follow a different set of computational rules, bypassing normalization, a canonical visual computation.

  19. 46 CFR Appendix B to Part 154 - Stress Analyses Definitions

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Stress Analyses Definitions B Appendix B to Part 154...—Stress Analyses Definitions The following are the standard definitions of stresses for the analysis of an independent tank type B: Normal stress means the component of stress normal to the plane of reference...

  20. Nonsymmetric entropy and maximum nonsymmetric entropy principle

    International Nuclear Information System (INIS)

    Liu Chengshi

    2009-01-01

    Under the frame of a statistical model, the concept of nonsymmetric entropy which generalizes the concepts of Boltzmann's entropy and Shannon's entropy, is defined. Maximum nonsymmetric entropy principle is proved. Some important distribution laws such as power law, can be derived from this principle naturally. Especially, nonsymmetric entropy is more convenient than other entropy such as Tsallis's entropy in deriving power laws.

  1. Maximum speed of dewetting on a fiber

    NARCIS (Netherlands)

    Chan, Tak Shing; Gueudre, Thomas; Snoeijer, Jacobus Hendrikus

    2011-01-01

    A solid object can be coated by a nonwetting liquid since a receding contact line cannot exceed a critical speed. We theoretically investigate this forced wetting transition for axisymmetric menisci on fibers of varying radii. First, we use a matched asymptotic expansion and derive the maximum speed

  2. Maximum potential preventive effect of hip protectors

    NARCIS (Netherlands)

    van Schoor, N.M.; Smit, J.H.; Bouter, L.M.; Veenings, B.; Asma, G.B.; Lips, P.T.A.M.

    2007-01-01

    OBJECTIVES: To estimate the maximum potential preventive effect of hip protectors in older persons living in the community or homes for the elderly. DESIGN: Observational cohort study. SETTING: Emergency departments in the Netherlands. PARTICIPANTS: Hip fracture patients aged 70 and older who

  3. Maximum gain of Yagi-Uda arrays

    DEFF Research Database (Denmark)

    Bojsen, J.H.; Schjær-Jacobsen, Hans; Nilsson, E.

    1971-01-01

    Numerical optimisation techniques have been used to find the maximum gain of some specific parasitic arrays. The gain of an array of infinitely thin, equispaced dipoles loaded with arbitrary reactances has been optimised. The results show that standard travelling-wave design methods are not optimum....... Yagi–Uda arrays with equal and unequal spacing have also been optimised with experimental verification....

  4. correlation between maximum dry density and cohesion

    African Journals Online (AJOL)

    HOD

    represents maximum dry density, signifies plastic limit and is liquid limit. Researchers [6, 7] estimate compaction parameters. Aside from the correlation existing between compaction parameters and other physical quantities there are some other correlations that have been investigated by other researchers. The well-known.

  5. Weak scale from the maximum entropy principle

    Science.gov (United States)

    Hamada, Yuta; Kawai, Hikaru; Kawana, Kiyoharu

    2015-03-01

    The theory of the multiverse and wormholes suggests that the parameters of the Standard Model (SM) are fixed in such a way that the radiation of the S3 universe at the final stage S_rad becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the SM, we can check whether S_rad actually becomes maximum at the observed values. In this paper, we regard S_rad at the final stage as a function of the weak scale (the Higgs expectation value) vh, and show that it becomes maximum around vh = {{O}} (300 GeV) when the dimensionless couplings in the SM, i.e., the Higgs self-coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by vh ˜ T_{BBN}2 / (M_{pl}ye5), where ye is the Yukawa coupling of electron, T_BBN is the temperature at which the Big Bang nucleosynthesis starts, and M_pl is the Planck mass.

  6. The maximum-entropy method in superspace

    Czech Academy of Sciences Publication Activity Database

    van Smaalen, S.; Palatinus, Lukáš; Schneider, M.

    2003-01-01

    Roč. 59, - (2003), s. 459-469 ISSN 0108-7673 Grant - others:DFG(DE) XX Institutional research plan: CEZ:AV0Z1010914 Keywords : maximum-entropy method, * aperiodic crystals * electron density Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.558, year: 2003

  7. Achieving maximum sustainable yield in mixed fisheries

    NARCIS (Netherlands)

    Ulrich, Clara; Vermard, Youen; Dolder, Paul J.; Brunel, Thomas; Jardim, Ernesto; Holmes, Steven J.; Kempf, Alexander; Mortensen, Lars O.; Poos, Jan Jaap; Rindorf, Anna

    2017-01-01

    Achieving single species maximum sustainable yield (MSY) in complex and dynamic fisheries targeting multiple species (mixed fisheries) is challenging because achieving the objective for one species may mean missing the objective for another. The North Sea mixed fisheries are a representative example

  8. 5 CFR 534.203 - Maximum stipends.

    Science.gov (United States)

    2010-01-01

    ... maximum stipend established under this section. (e) A trainee at a non-Federal hospital, clinic, or medical or dental laboratory who is assigned to a Federal hospital, clinic, or medical or dental... Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY UNDER OTHER SYSTEMS Student...

  9. Minimal length, Friedmann equations and maximum density

    Energy Technology Data Exchange (ETDEWEB)

    Awad, Adel [Center for Theoretical Physics, British University of Egypt,Sherouk City 11837, P.O. Box 43 (Egypt); Department of Physics, Faculty of Science, Ain Shams University,Cairo, 11566 (Egypt); Ali, Ahmed Farag [Centre for Fundamental Physics, Zewail City of Science and Technology,Sheikh Zayed, 12588, Giza (Egypt); Department of Physics, Faculty of Science, Benha University,Benha, 13518 (Egypt)

    2014-06-16

    Inspired by Jacobson’s thermodynamic approach, Cai et al. have shown the emergence of Friedmann equations from the first law of thermodynamics. We extend Akbar-Cai derivation http://dx.doi.org/10.1103/PhysRevD.75.084003 of Friedmann equations to accommodate a general entropy-area law. Studying the resulted Friedmann equations using a specific entropy-area law, which is motivated by the generalized uncertainty principle (GUP), reveals the existence of a maximum energy density closed to Planck density. Allowing for a general continuous pressure p(ρ,a) leads to bounded curvature invariants and a general nonsingular evolution. In this case, the maximum energy density is reached in a finite time and there is no cosmological evolution beyond this point which leaves the big bang singularity inaccessible from a spacetime prospective. The existence of maximum energy density and a general nonsingular evolution is independent of the equation of state and the spacial curvature k. As an example we study the evolution of the equation of state p=ωρ through its phase-space diagram to show the existence of a maximum energy which is reachable in a finite time.

  10. Stress Management: Job Stress

    Science.gov (United States)

    Healthy Lifestyle Stress management Job stress can be all-consuming — but it doesn't have to be. Address your triggers, keep perspective and ... stress triggers, it's often helpful to improve time management skills — especially if you tend to feel overwhelmed ...

  11. Influence of maximum bite force on jaw movement during gummy jelly mastication.

    Science.gov (United States)

    Kuninori, T; Tomonari, H; Uehara, S; Kitashima, F; Yagi, T; Miyawaki, S

    2014-05-01

    It is known that maximum bite force has various influences on chewing function; however, there have not been studies in which the relationships between maximum bite force and masticatory jaw movement have been clarified. The aim of this study was to investigate the effect of maximum bite force on masticatory jaw movement in subjects with normal occlusion. Thirty young adults (22 men and 8 women; mean age, 22.6 years) with good occlusion were divided into two groups based on whether they had a relatively high or low maximum bite force according to the median. The maximum bite force was determined according to the Dental Prescale System using pressure-sensitive sheets. Jaw movement during mastication of hard gummy jelly (each 5.5 g) on the preferred chewing side was recorded using a six degrees of freedom jaw movement recording system. The motion of the lower incisal point of the mandible was computed, and the mean values of 10 cycles (cycles 2-11) were calculated. A masticatory performance test was conducted using gummy jelly. Subjects with a lower maximum bite force showed increased maximum lateral amplitude, closing distance, width and closing angle; wider masticatory jaw movement; and significantly lower masticatory performance. However, no differences in the maximum vertical or maximum anteroposterior amplitudes were observed between the groups. Although other factors, such as individual morphology, may influence masticatory jaw movement, our results suggest that subjects with a lower maximum bite force show increased lateral jaw motion during mastication. © 2014 John Wiley & Sons Ltd.

  12. Childhood Stress

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Childhood Stress KidsHealth / For Parents / Childhood Stress What's in this ... and feel stress to some degree. Sources of Stress Stress is a function of the demands placed ...

  13. Normal Pressure Hydrocephalus

    Science.gov (United States)

    ... improves the chance of a good recovery. Without treatment, symptoms may worsen and cause death. What research is being done? The NINDS conducts and supports research on neurological disorders, including normal pressure hydrocephalus. Research on disorders such ...

  14. Normality in Analytical Psychology

    Science.gov (United States)

    Myers, Steve

    2013-01-01

    Although C.G. Jung’s interest in normality wavered throughout his career, it was one of the areas he identified in later life as worthy of further research. He began his career using a definition of normality which would have been the target of Foucault’s criticism, had Foucault chosen to review Jung’s work. However, Jung then evolved his thinking to a standpoint that was more aligned to Foucault’s own. Thereafter, the post Jungian concept of normality has remained relatively undeveloped by comparison with psychoanalysis and mainstream psychology. Jung’s disjecta membra on the subject suggest that, in contemporary analytical psychology, too much focus is placed on the process of individuation to the neglect of applications that consider collective processes. Also, there is potential for useful research and development into the nature of conflict between individuals and societies, and how normal people typically develop in relation to the spectrum between individuation and collectivity. PMID:25379262

  15. Normal pressure hydrocephalus

    Science.gov (United States)

    Hydrocephalus - occult; Hydrocephalus - idiopathic; Hydrocephalus - adult; Hydrocephalus - communicating; Dementia - hydrocephalus; NPH ... Ferri FF. Normal pressure hydrocephalus. In: Ferri FF, ed. ... Elsevier; 2016:chap 648. Rosenberg GA. Brain edema and disorders ...

  16. Normal Functioning Family

    Science.gov (United States)

    ... Spread the Word Shop AAP Find a Pediatrician Family Life Medical Home Family Dynamics Adoption & Foster Care ... Español Text Size Email Print Share Normal Functioning Family Page Content Article Body Is there any way ...

  17. Normal growth and development

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002456.htm Normal growth and development To use the sharing features on this page, please enable JavaScript. A child's growth and development can be divided into four periods: ...

  18. Stress transmission in soil

    DEFF Research Database (Denmark)

    Lamandé, Mathieu; Schjønning, Per

    We urgently need increased quantitative knowledge on stress transmission in real soils loaded with agricultural machinery. 3D measurements of vertical stresses under tracked wheels were performed in situ in a Stagnic Luvisol (clay content 20 %) continuously cropped with small grain cereals......). Seven load cells were inserted horizontally from a pit with minimal disturbance of soil in each of three depths (0.3, 0.6 and 0.9 m), covering the width of the wheeled area. The position of the wheel relative to the transducers was recorded using a laser sensor. Finally, the vertical stresses near...... the soil-tyre interface were measured in separate tests by 17 stress transducers across the width of the tyres. The results showed that the inflation pressure controlled the level of maximum stresses at 0.3 m depth, while the wheel load was correlated to the measured stresses at 0.9 m depth. This supports...

  19. The concept of the average stress in the fracture process zone for the search of the crack path

    Directory of Open Access Journals (Sweden)

    Yu.G. Matvienko

    2015-10-01

    Full Text Available The concept of the average stress has been employed to propose the maximum average tangential stress (MATS criterion for predicting the direction of fracture angle. This criterion states that a crack grows when the maximum average tangential stress in the fracture process zone ahead of the crack tip reaches its critical value and the crack growth direction coincides with the direction of the maximum average tangential stress along a constant radius around the crack tip. The tangential stress is described by the singular and nonsingular (T-stress terms in the Williams series solution. To demonstrate the validity of the proposed MATS criterion, this criterion is directly applied to experiments reported in the literature for the mixed mode I/II crack growth behavior of Guiting limestone. The predicted directions of fracture angle are consistent with the experimental data. The concept of the average stress has been also employed to predict the surface crack path under rolling-sliding contact loading. The proposed model considers the size and orientation of the initial crack, normal and tangential loading due to rolling–sliding contact as well as the influence of fluid trapped inside the crack by a hydraulic pressure mechanism. The MATS criterion is directly applied to equivalent contact model for surface crack growth on a gear tooth flank.

  20. Measurement of the temperature of density maximum of water solutions using a convective flow technique

    OpenAIRE

    Cawley, M.F.; McGlynn, D.; Mooney, P.A.

    2006-01-01

    A technique is described which yields an accurate measurement of the temperature of density maximum of fluids which exhibit such anomalous behaviour. The method relies on the detection of changes in convective flow in a rectangular cavity containing the test fluid.The normal single-cell convection which occurs in the presence of a horizontal temperature gradient changes to a double cell configuration in the vicinity of the density maximum, and this transition manifests itself in changes in th...

  1. Maximum concentrations at work and maximum biologically tolerable concentration for working materials 1991

    International Nuclear Information System (INIS)

    1991-01-01

    The meaning of the term 'maximum concentration at work' in regard of various pollutants is discussed. Specifically, a number of dusts and smokes are dealt with. The valuation criteria for maximum biologically tolerable concentrations for working materials are indicated. The working materials in question are corcinogeneous substances or substances liable to cause allergies or mutate the genome. (VT) [de

  2. 75 FR 43840 - Inflation Adjustment of the Ordinary Maximum and Aggravated Maximum Civil Monetary Penalties for...

    Science.gov (United States)

    2010-07-27

    ...-17530; Notice No. 2] RIN 2130-ZA03 Inflation Adjustment of the Ordinary Maximum and Aggravated Maximum... remains at $250. These adjustments are required by the Federal Civil Penalties Inflation Adjustment Act [email protected] . SUPPLEMENTARY INFORMATION: The Federal Civil Penalties Inflation Adjustment Act of 1990...

  3. Parameter Estimations and Optimal Design of Simple Step-Stress Model for Gamma Dual Weibull Distribution

    Directory of Open Access Journals (Sweden)

    Hamdy Mohamed Salem

    2018-03-01

    Full Text Available This paper considers life-testing experiments and how it is effected by stress factors: namely temperature, electricity loads, cycling rate and pressure. A major type of accelerated life tests is a step-stress model that allows the experimenter to increase stress levels more than normal use during the experiment to see the failure items. The test items are assumed to follow Gamma Dual Weibull distribution. Different methods for estimating the parameters are discussed. These include Maximum Likelihood Estimations and Confidence Interval Estimations which is based on asymptotic normality generate narrow intervals to the unknown distribution parameters with high probability. MathCAD (2001 program is used to illustrate the optimal time procedure through numerical examples.

  4. Zipf's law, power laws and maximum entropy

    International Nuclear Information System (INIS)

    Visser, Matt

    2013-01-01

    Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines—from astronomy to demographics to software structure to economics to linguistics to zoology, and even warfare. A recent model of random group formation (RGF) attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present paper I argue that the specific cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified. (paper)

  5. Maximum-entropy description of animal movement.

    Science.gov (United States)

    Fleming, Chris H; Subaşı, Yiğit; Calabrese, Justin M

    2015-03-01

    We introduce a class of maximum-entropy states that naturally includes within it all of the major continuous-time stochastic processes that have been applied to animal movement, including Brownian motion, Ornstein-Uhlenbeck motion, integrated Ornstein-Uhlenbeck motion, a recently discovered hybrid of the previous models, and a new model that describes central-place foraging. We are also able to predict a further hierarchy of new models that will emerge as data quality improves to better resolve the underlying continuity of animal movement. Finally, we also show that Langevin equations must obey a fluctuation-dissipation theorem to generate processes that fall from this class of maximum-entropy distributions when the constraints are purely kinematic.

  6. Pareto versus lognormal: a maximum entropy test.

    Science.gov (United States)

    Bee, Marco; Riccaboni, Massimo; Schiavo, Stefano

    2011-08-01

    It is commonly found that distributions that seem to be lognormal over a broad range change to a power-law (Pareto) distribution for the last few percentiles. The distributions of many physical, natural, and social events (earthquake size, species abundance, income and wealth, as well as file, city, and firm sizes) display this structure. We present a test for the occurrence of power-law tails in statistical distributions based on maximum entropy. This methodology allows one to identify the true data-generating processes even in the case when it is neither lognormal nor Pareto. The maximum entropy approach is then compared with other widely used methods and applied to different levels of aggregation of complex systems. Our results provide support for the theory that distributions with lognormal body and Pareto tail can be generated as mixtures of lognormally distributed units.

  7. Maximum likelihood estimation for integrated diffusion processes

    DEFF Research Database (Denmark)

    Baltazar-Larios, Fernando; Sørensen, Michael

    We propose a method for obtaining maximum likelihood estimates of parameters in diffusion models when the data is a discrete time sample of the integral of the process, while no direct observations of the process itself are available. The data are, moreover, assumed to be contaminated...... EM-algorithm to obtain maximum likelihood estimates of the parameters in the diffusion model. As part of the algorithm, we use a recent simple method for approximate simulation of diffusion bridges. In simulation studies for the Ornstein-Uhlenbeck process and the CIR process the proposed method works...... by measurement errors. Integrated volatility is an example of this type of observations. Another example is ice-core data on oxygen isotopes used to investigate paleo-temperatures. The data can be viewed as incomplete observations of a model with a tractable likelihood function. Therefore we propose a simulated...

  8. A Maximum Radius for Habitable Planets.

    Science.gov (United States)

    Alibert, Yann

    2015-09-01

    We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope.

  9. Maximum parsimony on subsets of taxa.

    Science.gov (United States)

    Fischer, Mareike; Thatte, Bhalchandra D

    2009-09-21

    In this paper we investigate mathematical questions concerning the reliability (reconstruction accuracy) of Fitch's maximum parsimony algorithm for reconstructing the ancestral state given a phylogenetic tree and a character. In particular, we consider the question whether the maximum parsimony method applied to a subset of taxa can reconstruct the ancestral state of the root more accurately than when applied to all taxa, and we give an example showing that this indeed is possible. A surprising feature of our example is that ignoring a taxon closer to the root improves the reliability of the method. On the other hand, in the case of the two-state symmetric substitution model, we answer affirmatively a conjecture of Li, Steel and Zhang which states that under a molecular clock the probability that the state at a single taxon is a correct guess of the ancestral state is a lower bound on the reconstruction accuracy of Fitch's method applied to all taxa.

  10. Maximum entropy analysis of liquid diffraction data

    International Nuclear Information System (INIS)

    Root, J.H.; Egelstaff, P.A.; Nickel, B.G.

    1986-01-01

    A maximum entropy method for reducing truncation effects in the inverse Fourier transform of structure factor, S(q), to pair correlation function, g(r), is described. The advantages and limitations of the method are explored with the PY hard sphere structure factor as model input data. An example using real data on liquid chlorine, is then presented. It is seen that spurious structure is greatly reduced in comparison to traditional Fourier transform methods. (author)

  11. A Maximum Resonant Set of Polyomino Graphs

    Directory of Open Access Journals (Sweden)

    Zhang Heping

    2016-05-01

    Full Text Available A polyomino graph P is a connected finite subgraph of the infinite plane grid such that each finite face is surrounded by a regular square of side length one and each edge belongs to at least one square. A dimer covering of P corresponds to a perfect matching. Different dimer coverings can interact via an alternating cycle (or square with respect to them. A set of disjoint squares of P is a resonant set if P has a perfect matching M so that each one of those squares is M-alternating. In this paper, we show that if K is a maximum resonant set of P, then P − K has a unique perfect matching. We further prove that the maximum forcing number of a polyomino graph is equal to the cardinality of a maximum resonant set. This confirms a conjecture of Xu et al. [26]. We also show that if K is a maximal alternating set of P, then P − K has a unique perfect matching.

  12. Automatic maximum entropy spectral reconstruction in NMR

    International Nuclear Information System (INIS)

    Mobli, Mehdi; Maciejewski, Mark W.; Gryk, Michael R.; Hoch, Jeffrey C.

    2007-01-01

    Developments in superconducting magnets, cryogenic probes, isotope labeling strategies, and sophisticated pulse sequences together have enabled the application, in principle, of high-resolution NMR spectroscopy to biomolecular systems approaching 1 megadalton. In practice, however, conventional approaches to NMR that utilize the fast Fourier transform, which require data collected at uniform time intervals, result in prohibitively lengthy data collection times in order to achieve the full resolution afforded by high field magnets. A variety of approaches that involve nonuniform sampling have been proposed, each utilizing a non-Fourier method of spectrum analysis. A very general non-Fourier method that is capable of utilizing data collected using any of the proposed nonuniform sampling strategies is maximum entropy reconstruction. A limiting factor in the adoption of maximum entropy reconstruction in NMR has been the need to specify non-intuitive parameters. Here we describe a fully automated system for maximum entropy reconstruction that requires no user-specified parameters. A web-accessible script generator provides the user interface to the system

  13. maximum neutron flux at thermal nuclear reactors

    International Nuclear Information System (INIS)

    Strugar, P.

    1968-10-01

    Since actual research reactors are technically complicated and expensive facilities it is important to achieve savings by appropriate reactor lattice configurations. There is a number of papers, and practical examples of reactors with central reflector, dealing with spatial distribution of fuel elements which would result in higher neutron flux. Common disadvantage of all the solutions is that the choice of best solution is done starting from the anticipated spatial distributions of fuel elements. The weakness of these approaches is lack of defined optimization criteria. Direct approach is defined as follows: determine the spatial distribution of fuel concentration starting from the condition of maximum neutron flux by fulfilling the thermal constraints. Thus the problem of determining the maximum neutron flux is solving a variational problem which is beyond the possibilities of classical variational calculation. This variational problem has been successfully solved by applying the maximum principle of Pontrjagin. Optimum distribution of fuel concentration was obtained in explicit analytical form. Thus, spatial distribution of the neutron flux and critical dimensions of quite complex reactor system are calculated in a relatively simple way. In addition to the fact that the results are innovative this approach is interesting because of the optimization procedure itself [sr

  14. The Semiparametric Normal Variance-Mean Mixture Model

    DEFF Research Database (Denmark)

    Korsholm, Lars

    1997-01-01

    We discuss the normal vairance-mean mixture model from a semi-parametric point of view, i.e. we let the mixing distribution belong to a non parametric family. The main results are consistency of the non parametric maximum likelihood estimat or in this case, and construction of an asymptotically...... normal and efficient estimator....

  15. Interaction between a normal shock wave and a turbulent boundary layer at high transonic speeds. Part 1: Pressure distribution. Part 2: Wall shear stress. Part 3: Simplified formulas for the prediction of surface pressures and skin friction

    Science.gov (United States)

    Adamson, T. C., Jr.; Liou, M. S.; Messiter, A. F.

    1980-01-01

    An asymptotic description is derived for the interaction between a shock wave and a turbulent boundary layer in transonic flow, for a particular limiting case. The dimensionless difference between the external flow velocity and critical sound speed is taken to be much smaller than one, but large in comparison with the dimensionless friction velocity. The basic results are derived for a flat plate, and corrections for longitudinal wall curvature and for flow in a circular pipe are also shown. Solutions are given for the wall pressure distribution and the shape of the shock wave. Solutions for the wall shear stress are obtained, and a criterion for incipient separation is derived. Simplified solutions for both the wall pressure and skin friction distributions in the interaction region are given. These results are presented in a form suitable for use in computer programs.

  16. Smooth quantile normalization.

    Science.gov (United States)

    Hicks, Stephanie C; Okrah, Kwame; Paulson, Joseph N; Quackenbush, John; Irizarry, Rafael A; Bravo, Héctor Corrada

    2018-04-01

    Between-sample normalization is a critical step in genomic data analysis to remove systematic bias and unwanted technical variation in high-throughput data. Global normalization methods are based on the assumption that observed variability in global properties is due to technical reasons and are unrelated to the biology of interest. For example, some methods correct for differences in sequencing read counts by scaling features to have similar median values across samples, but these fail to reduce other forms of unwanted technical variation. Methods such as quantile normalization transform the statistical distributions across samples to be the same and assume global differences in the distribution are induced by only technical variation. However, it remains unclear how to proceed with normalization if these assumptions are violated, for example, if there are global differences in the statistical distributions between biological conditions or groups, and external information, such as negative or control features, is not available. Here, we introduce a generalization of quantile normalization, referred to as smooth quantile normalization (qsmooth), which is based on the assumption that the statistical distribution of each sample should be the same (or have the same distributional shape) within biological groups or conditions, but allowing that they may differ between groups. We illustrate the advantages of our method on several high-throughput datasets with global differences in distributions corresponding to different biological conditions. We also perform a Monte Carlo simulation study to illustrate the bias-variance tradeoff and root mean squared error of qsmooth compared to other global normalization methods. A software implementation is available from https://github.com/stephaniehicks/qsmooth.

  17. Ascorbate/menadione-induced oxidative stress kills cancer cells that express normal or mutated forms of the oncogenic protein Bcr-Abl. An in vitro and in vivo mechanistic study.

    Science.gov (United States)

    Beck, Raphaël; Pedrosa, Rozangela Curi; Dejeans, Nicolas; Glorieux, Christophe; Levêque, Philippe; Gallez, Bernard; Taper, Henryk; Eeckhoudt, Stéphane; Knoops, Laurent; Calderon, Pedro Buc; Verrax, Julien

    2011-10-01

    Numerous studies suggest that generation of oxidative stress could be useful in cancer treatment. In this study, we evaluated, in vitro and in vivo, the antitumor potential of oxidative stress induced by ascorbate/menadione (asc/men). This combination of a reducing agent (ascorbate) and a redox active quinone (menadione) generates redox cycling leading to formation of reactive oxygen species (ROS). Asc/men was tested in several cell types including K562 cells (a stable human-derived leukemia cell line), freshly isolated leukocytes from patients with chronic myeloid leukemia, BaF3 cells (a murine pro-B cell line) transfected with Bcr-Abl and peripheral blood leukocytes derived from healthy donors. Although these latter cells were resistant to asc/men, survival of all the other cell lines was markedly reduced, including the BaF3 cells expressing either wild-type or mutated Bcr-Abl. In a standard in vivo model of subcutaneous tumor transplantation, asc/men provoked a significant delay in the proliferation of K562 and BaF3 cells expressing the T315I mutated form of Bcr-Abl. No effect of asc/men was observed when these latter cells were injected into blood of mice most probably because of the high antioxidant potential of red blood cells, as shown by in vitro experiments. We postulate that cancer cells are more sensitive to asc/men than healthy cells because of their lack of antioxidant enzymes, mainly catalase. The mechanism underlying this cytotoxicity involves the oxidative cleavage of Hsp90 with a subsequent loss of its chaperone function thus leading to degradation of wild-type and mutated Bcr-Abl protein.

  18. Stress in ion-implanted CVD Si3N4 films

    International Nuclear Information System (INIS)

    EerNisse, E.P.

    1977-01-01

    The compressive stress buildup caused in chemical-vapor-deposited (CVD) Si 3 N 4 films by ion implantation is shown to be caused entirely by atomic collision effects, ionization effects being unimportant. The stress introduction rate is shown to be independent of CVD processing variables and O content of the film. The maximum attainable compressive stress change is 3.5 x 10 10 dyn/cm 2 , resulting in a maximum net compressive stress of 2 x 10 10 dyn/cm 2 for films on Si where the as-deposited films inherently have 1.5 x 10 10 dyn/cm 2 tensile stress before ion implantation. Results are presented which show that O in the films inhibits thermal annealing of the ion-implantation-induced compressive stress. Results for introduction rate and annealing effects are presented in normalized form so that workers can use the effects for intentional stress level adjustment in the films to reduce probability of cracking and detachment

  19. The effect of inertia, viscous damping, temperature and normal ...

    Indian Academy of Sciences (India)

    Nitish Sinha

    2018-04-16

    Apr 16, 2018 ... physical parameters such as inertia, viscous damping, temperature and normal stress on the chaotic ... However, the present study has shown the appearance of chaos for the specific .... Although chaos is a general man-.

  20. Radionuclide ventriculography during rest and exercise: normal values

    International Nuclear Information System (INIS)

    Ludwig, E.B.; Marroni, B.J.; Achutti, A.C.; Anselmi, O.E.; Rabin, M.

    1983-01-01

    Twenty young volunteers of both sexes were examined by radioisotopic techniques to establish the normal range of ventricular function at rest and the response to a stress test (systolic arterious pressure X cardiac frequency > 25000). (M.A.C.) [pt

  1. Evaluation of 14 winter bread wheat genotypes in normal irrigation ...

    African Journals Online (AJOL)

    Evaluation of 14 winter bread wheat genotypes in normal irrigation and stress conditions after anthesis stage. ... African Journal of Biotechnology ... Using biplot graphic method, comparison of indices amounts and mean rating of indices for ...

  2. Behavior of durum wheat genotypes under normal irrigation and ...

    African Journals Online (AJOL)

    Behavior of durum wheat genotypes under normal irrigation and drought stress conditions in the greenhouse. ... African Journal of Biotechnology ... Genotypes were grouped in cluster analysis (using Ward's method) based on Yp, Ys and ...

  3. Accurate Maximum Power Tracking in Photovoltaic Systems Affected by Partial Shading

    Directory of Open Access Journals (Sweden)

    Pierluigi Guerriero

    2015-01-01

    Full Text Available A maximum power tracking algorithm exploiting operating point information gained on individual solar panels is presented. The proposed algorithm recognizes the presence of multiple local maxima in the power voltage curve of a shaded solar field and evaluates the coordinated of the absolute maximum. The effectiveness of the proposed approach is evidenced by means of circuit level simulation and experimental results. Experiments evidenced that, in comparison with a standard perturb and observe algorithm, we achieve faster convergence in normal operating conditions (when the solar field is uniformly illuminated and we accurately locate the absolute maximum power point in partial shading conditions, thus avoiding the convergence on local maxima.

  4. Review of construction criteria for nuclear fuels under normal operation and anticipated operational occurrences - a literature study; Oeversyn av konstruktionskriterier foer kaernbraensle under normaldrift och foervaentade driftsstoerningar - en litteraturstudie

    Energy Technology Data Exchange (ETDEWEB)

    Rudling, P. [Advanced Nuclear Technology, Uppsala (Sweden)

    1999-06-01

    General Design Criteria 10, GDC 10, in the Code of Federal Regulation Part 50 of Nuclear Regulatory Commission specifies that the fuel assembly including the fuel rod may not be damaged during normal operation and anticipated operational occurrences. No damaged, means that the fuel rods do not fail, that fuel rod and assembly dimensions remain within operational tolerances, and that functional capabilities are not reduced below those assumed in the safety analysis. This objective is given by GDC 10, and the design limits that are required to accomplish this objective are called Specified Acceptable Fuel Design Limits, SAFDLs. The SAFDLs are specified in Standard Review Plan, SRP, chapter 4.2. This report summarises and analyses published open data that are relevant for the below-specified SAFDLs. It also summarises the current view of NRC on the discussed SAFDLs as well as the margin towards fuel failure of the SAFDLs. The following SAFDLs are discussed herein: Avoidance of fuel centre melting; Avoidance of liftoff; Maximum cladding creep deformation; Avoidance of cladding collapse; Maximum fretting; Maximum dimensional changes; Maximum stresses; Maximum fatigue stresses; Maximum oxide thickness; Maximum hydrogen content; Avoidance of PCI - failures.

  5. Monitoring the normal body

    DEFF Research Database (Denmark)

    Nissen, Nina Konstantin; Holm, Lotte; Baarts, Charlotte

    2015-01-01

    of practices for monitoring their bodies based on different kinds of calculations of weight and body size, observations of body shape, and measurements of bodily firmness. Biometric measurements are familiar to them as are health authorities' recommendations. Despite not belonging to an extreme BMI category...... provides us with knowledge about how to prevent future overweight or obesity. This paper investigates body size ideals and monitoring practices among normal-weight and moderately overweight people. Methods : The study is based on in-depth interviews combined with observations. 24 participants were...... recruited by strategic sampling based on self-reported BMI 18.5-29.9 kg/m2 and socio-demographic factors. Inductive analysis was conducted. Results : Normal-weight and moderately overweight people have clear ideals for their body size. Despite being normal weight or close to this, they construct a variety...

  6. Normal modified stable processes

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Shephard, N.

    2002-01-01

    Gaussian (NGIG) laws. The wider framework thus established provides, in particular, for added flexibility in the modelling of the dynamics of financial time series, of importance especially as regards OU based stochastic volatility models for equities. In the special case of the tempered stable OU process......This paper discusses two classes of distributions, and stochastic processes derived from them: modified stable (MS) laws and normal modified stable (NMS) laws. This extends corresponding results for the generalised inverse Gaussian (GIG) and generalised hyperbolic (GH) or normal generalised inverse...

  7. Normalization of satellite imagery

    Science.gov (United States)

    Kim, Hongsuk H.; Elman, Gregory C.

    1990-01-01

    Sets of Thematic Mapper (TM) imagery taken over the Washington, DC metropolitan area during the months of November, March and May were converted into a form of ground reflectance imagery. This conversion was accomplished by adjusting the incident sunlight and view angles and by applying a pixel-by-pixel correction for atmospheric effects. Seasonal color changes of the area can be better observed when such normalization is applied to space imagery taken in time series. In normalized imagery, the grey scale depicts variations in surface reflectance and tonal signature of multi-band color imagery can be directly interpreted for quantitative information of the target.

  8. The normal holonomy group

    International Nuclear Information System (INIS)

    Olmos, C.

    1990-05-01

    The restricted holonomy group of a Riemannian manifold is a compact Lie group and its representation on the tangent space is a product of irreducible representations and a trivial one. Each one of the non-trivial factors is either an orthogonal representation of a connected compact Lie group which acts transitively on the unit sphere or it is the isotropy representation of a single Riemannian symmetric space of rank ≥ 2. We prove that, all these properties are also true for the representation on the normal space of the restricted normal holonomy group of any submanifold of a space of constant curvature. 4 refs

  9. Upper respiratory tract nociceptor stimulation and stress response following acute and repeated Cyfluthrin inhalation in normal and pregnant rats: Physiological rat-specific adaptions can easily be misunderstood as adversities.

    Science.gov (United States)

    Pauluhn, Juergen

    2018-01-05

    This paper reviews the results from past regulatory and mechanistic inhalation studies in rats with the type II pyrethroid Cyfluthrin. Apart from many chemical irritants, Cyfluthrin was shown to be a neuroexcitatory agent without any inherent tissue-destructive or irritant property. Thus, any Cyfluthrin-induced neuroexcitatory afferent sensory stimulus from peripheral nociceptors in the upper respiratory tract is likely to be perceived as a transient stimulus triggering annoyance and/or avoidance by both rats and humans. However, while thermolabile rats respond to such stresses reflexively, homeothermic humans appear to respond psychologically. With this focus in mind, past inhalation studies in rats and human volunteers were reevaluated and assessed to identify common denominators to such neuroexcitatory stimuli upon inhalation exposure. This analysis supports the conclusion that the adaptive physiological response occurring in rats secondary to such chemosensory stimuli requires inhalation exposures above the chemosensory threshold. Rats, a species known to undergo adaptively a hibernation-like physiological state upon environmental stresses, experienced reflexively-induced bradypnea, bradycardia, hypothermia, and changes in acid-base status during inhalation exposure. After cessation of the sensory stimulus, rapid recovery occurred. Physiological data of male and female rats from a 4-week repeated inhalation study (exposure 6-h/day, 5-times/week) were used to select concentration for a 10-day developmental inhalation toxicity study in pregnant rats. Maternal hypothermia and hypoventilation were identified as likely cause of fetal and placental growth retardations because of a maternal adaptation-driven reduced feto-placental transfer of oxygen. In summary, maternal reflex-hypothermia, reduced cardiac output and placental perfusion, and disruption of the gestation-related hyperventilation are believed to be the maternally mediated causes for developmental

  10. Maximum entropy decomposition of quadrupole mass spectra

    International Nuclear Information System (INIS)

    Toussaint, U. von; Dose, V.; Golan, A.

    2004-01-01

    We present an information-theoretic method called generalized maximum entropy (GME) for decomposing mass spectra of gas mixtures from noisy measurements. In this GME approach to the noisy, underdetermined inverse problem, the joint entropies of concentration, cracking, and noise probabilities are maximized subject to the measured data. This provides a robust estimation for the unknown cracking patterns and the concentrations of the contributing molecules. The method is applied to mass spectroscopic data of hydrocarbons, and the estimates are compared with those received from a Bayesian approach. We show that the GME method is efficient and is computationally fast

  11. Maximum power operation of interacting molecular motors

    DEFF Research Database (Denmark)

    Golubeva, Natalia; Imparato, Alberto

    2013-01-01

    , as compared to the non-interacting system, in a wide range of biologically compatible scenarios. We furthermore consider the case where the motor-motor interaction directly affects the internal chemical cycle and investigate the effect on the system dynamics and thermodynamics.......We study the mechanical and thermodynamic properties of different traffic models for kinesin which are relevant in biological and experimental contexts. We find that motor-motor interactions play a fundamental role by enhancing the thermodynamic efficiency at maximum power of the motors...

  12. Maximum entropy method in momentum density reconstruction

    International Nuclear Information System (INIS)

    Dobrzynski, L.; Holas, A.

    1997-01-01

    The Maximum Entropy Method (MEM) is applied to the reconstruction of the 3-dimensional electron momentum density distributions observed through the set of Compton profiles measured along various crystallographic directions. It is shown that the reconstruction of electron momentum density may be reliably carried out with the aid of simple iterative algorithm suggested originally by Collins. A number of distributions has been simulated in order to check the performance of MEM. It is shown that MEM can be recommended as a model-free approach. (author). 13 refs, 1 fig

  13. On the maximum drawdown during speculative bubbles

    Science.gov (United States)

    Rotundo, Giulia; Navarra, Mauro

    2007-08-01

    A taxonomy of large financial crashes proposed in the literature locates the burst of speculative bubbles due to endogenous causes in the framework of extreme stock market crashes, defined as falls of market prices that are outlier with respect to the bulk of drawdown price movement distribution. This paper goes on deeper in the analysis providing a further characterization of the rising part of such selected bubbles through the examination of drawdown and maximum drawdown movement of indices prices. The analysis of drawdown duration is also performed and it is the core of the risk measure estimated here.

  14. Multi-Channel Maximum Likelihood Pitch Estimation

    DEFF Research Database (Denmark)

    Christensen, Mads Græsbøll

    2012-01-01

    In this paper, a method for multi-channel pitch estimation is proposed. The method is a maximum likelihood estimator and is based on a parametric model where the signals in the various channels share the same fundamental frequency but can have different amplitudes, phases, and noise characteristics....... This essentially means that the model allows for different conditions in the various channels, like different signal-to-noise ratios, microphone characteristics and reverberation. Moreover, the method does not assume that a certain array structure is used but rather relies on a more general model and is hence...

  15. Conductivity maximum in a charged colloidal suspension

    Energy Technology Data Exchange (ETDEWEB)

    Bastea, S

    2009-01-27

    Molecular dynamics simulations of a charged colloidal suspension in the salt-free regime show that the system exhibits an electrical conductivity maximum as a function of colloid charge. We attribute this behavior to two main competing effects: colloid effective charge saturation due to counterion 'condensation' and diffusion slowdown due to the relaxation effect. In agreement with previous observations, we also find that the effective transported charge is larger than the one determined by the Stern layer and suggest that it corresponds to the boundary fluid layer at the surface of the colloidal particles.

  16. Dynamical maximum entropy approach to flocking.

    Science.gov (United States)

    Cavagna, Andrea; Giardina, Irene; Ginelli, Francesco; Mora, Thierry; Piovani, Duccio; Tavarone, Raffaele; Walczak, Aleksandra M

    2014-04-01

    We derive a new method to infer from data the out-of-equilibrium alignment dynamics of collectively moving animal groups, by considering the maximum entropy model distribution consistent with temporal and spatial correlations of flight direction. When bird neighborhoods evolve rapidly, this dynamical inference correctly learns the parameters of the model, while a static one relying only on the spatial correlations fails. When neighbors change slowly and the detailed balance is satisfied, we recover the static procedure. We demonstrate the validity of the method on simulated data. The approach is applicable to other systems of active matter.

  17. Maximum Temperature Detection System for Integrated Circuits

    Science.gov (United States)

    Frankiewicz, Maciej; Kos, Andrzej

    2015-03-01

    The paper describes structure and measurement results of the system detecting present maximum temperature on the surface of an integrated circuit. The system consists of the set of proportional to absolute temperature sensors, temperature processing path and a digital part designed in VHDL. Analogue parts of the circuit where designed with full-custom technique. The system is a part of temperature-controlled oscillator circuit - a power management system based on dynamic frequency scaling method. The oscillator cooperates with microprocessor dedicated for thermal experiments. The whole system is implemented in UMC CMOS 0.18 μm (1.8 V) technology.

  18. Maximum entropy PDF projection: A review

    Science.gov (United States)

    Baggenstoss, Paul M.

    2017-06-01

    We review maximum entropy (MaxEnt) PDF projection, a method with wide potential applications in statistical inference. The method constructs a sampling distribution for a high-dimensional vector x based on knowing the sampling distribution p(z) of a lower-dimensional feature z = T (x). Under mild conditions, the distribution p(x) having highest possible entropy among all distributions consistent with p(z) may be readily found. Furthermore, the MaxEnt p(x) may be sampled, making the approach useful in Monte Carlo methods. We review the theorem and present a case study in model order selection and classification for handwritten character recognition.

  19. Multiperiod Maximum Loss is time unit invariant.

    Science.gov (United States)

    Kovacevic, Raimund M; Breuer, Thomas

    2016-01-01

    Time unit invariance is introduced as an additional requirement for multiperiod risk measures: for a constant portfolio under an i.i.d. risk factor process, the multiperiod risk should equal the one period risk of the aggregated loss, for an appropriate choice of parameters and independent of the portfolio and its distribution. Multiperiod Maximum Loss over a sequence of Kullback-Leibler balls is time unit invariant. This is also the case for the entropic risk measure. On the other hand, multiperiod Value at Risk and multiperiod Expected Shortfall are not time unit invariant.

  20. Maximum a posteriori decoder for digital communications

    Science.gov (United States)

    Altes, Richard A. (Inventor)

    1997-01-01

    A system and method for decoding by identification of the most likely phase coded signal corresponding to received data. The present invention has particular application to communication with signals that experience spurious random phase perturbations. The generalized estimator-correlator uses a maximum a posteriori (MAP) estimator to generate phase estimates for correlation with incoming data samples and for correlation with mean phases indicative of unique hypothesized signals. The result is a MAP likelihood statistic for each hypothesized transmission, wherein the highest value statistic identifies the transmitted signal.

  1. Improved Maximum Parsimony Models for Phylogenetic Networks.

    Science.gov (United States)

    Van Iersel, Leo; Jones, Mark; Scornavacca, Celine

    2018-05-01

    Phylogenetic networks are well suited to represent evolutionary histories comprising reticulate evolution. Several methods aiming at reconstructing explicit phylogenetic networks have been developed in the last two decades. In this article, we propose a new definition of maximum parsimony for phylogenetic networks that permits to model biological scenarios that cannot be modeled by the definitions currently present in the literature (namely, the "hardwired" and "softwired" parsimony). Building on this new definition, we provide several algorithmic results that lay the foundations for new parsimony-based methods for phylogenetic network reconstruction.

  2. Ancestral sequence reconstruction with Maximum Parsimony

    OpenAIRE

    Herbst, Lina; Fischer, Mareike

    2017-01-01

    One of the main aims in phylogenetics is the estimation of ancestral sequences based on present-day data like, for instance, DNA alignments. One way to estimate the data of the last common ancestor of a given set of species is to first reconstruct a phylogenetic tree with some tree inference method and then to use some method of ancestral state inference based on that tree. One of the best-known methods both for tree inference as well as for ancestral sequence inference is Maximum Parsimony (...

  3. Maximum support resistance with steel arch backfilling

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    A system of backfilling for roadway arch supports to replace timber and debris lagging is described. Produced in West Germany, it is known as the Bullflex system and consists of 23 cm diameter woven textile tubing which is inflated with a pumpable hydraulically-setting filler of the type normally used in mines. The tube is placed between the back of the support units and the rock face and creates an early-stage interlocking effect.

  4. Radiation pressure acceleration: The factors limiting maximum attainable ion energy

    Energy Technology Data Exchange (ETDEWEB)

    Bulanov, S. S.; Esarey, E.; Schroeder, C. B. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Bulanov, S. V. [KPSI, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215 (Japan); A. M. Prokhorov Institute of General Physics RAS, Moscow 119991 (Russian Federation); Esirkepov, T. Zh.; Kando, M. [KPSI, National Institutes for Quantum and Radiological Science and Technology, Kizugawa, Kyoto 619-0215 (Japan); Pegoraro, F. [Physics Department, University of Pisa and Istituto Nazionale di Ottica, CNR, Pisa 56127 (Italy); Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department, University of California, Berkeley, California 94720 (United States)

    2016-05-15

    Radiation pressure acceleration (RPA) is a highly efficient mechanism of laser-driven ion acceleration, with near complete transfer of the laser energy to the ions in the relativistic regime. However, there is a fundamental limit on the maximum attainable ion energy, which is determined by the group velocity of the laser. The tightly focused laser pulses have group velocities smaller than the vacuum light speed, and, since they offer the high intensity needed for the RPA regime, it is plausible that group velocity effects would manifest themselves in the experiments involving tightly focused pulses and thin foils. However, in this case, finite spot size effects are important, and another limiting factor, the transverse expansion of the target, may dominate over the group velocity effect. As the laser pulse diffracts after passing the focus, the target expands accordingly due to the transverse intensity profile of the laser. Due to this expansion, the areal density of the target decreases, making it transparent for radiation and effectively terminating the acceleration. The off-normal incidence of the laser on the target, due either to the experimental setup, or to the deformation of the target, will also lead to establishing a limit on maximum ion energy.

  5. Maximum surface level and temperature histories for Hanford waste tanks

    International Nuclear Information System (INIS)

    Flanagan, B.D.; Ha, N.D.; Huisingh, J.S.

    1994-01-01

    Radioactive defense waste resulting from the chemical processing of spent nuclear fuel has been accumulating at the Hanford Site since 1944. This waste is stored in underground waste-storage tanks. The Hanford Site Tank Farm Facilities Interim Safety Basis (ISB) provides a ready reference to the safety envelope for applicable tank farm facilities and installations. During preparation of the ISB, tank structural integrity concerns were identified as a key element in defining the safety envelope. These concerns, along with several deficiencies in the technical bases associated with the structural integrity issues and the corresponding operational limits/controls specified for conduct of normal tank farm operations are documented in the ISB. Consequently, a plan was initiated to upgrade the safety envelope technical bases by conducting Accelerated Safety Analyses-Phase 1 (ASA-Phase 1) sensitivity studies and additional structural evaluations. The purpose of this report is to facilitate the ASA-Phase 1 studies and future analyses of the single-shell tanks (SSTs) and double-shell tanks (DSTs) by compiling a quantitative summary of some of the past operating conditions the tanks have experienced during their existence. This report documents the available summaries of recorded maximum surface levels and maximum waste temperatures and references other sources for more specific data

  6. Design and analysis of a toroidal tester for the measurement of core losses under axial compressive stress

    Science.gov (United States)

    Alatawneh, Natheer; Rahman, Tanvir; Lowther, David A.; Chromik, Richard

    2017-06-01

    Electric machine cores are subjected to mechanical stresses due to manufacturing processes. These stresses include radial, circumferential and axial components that may have significant influences on the magnetic properties of the electrical steel and hence, on the output and efficiencies of electrical machines. Previously, most studies of iron losses due to mechanical stress have considered only radial and circumferential components. In this work, an improved toroidal tester has been designed and developed to measure the core losses and the magnetic properties of electrical steel under a compressive axial stress. The shape of the toroidal ring has been verified using 3D stress analysis. Also, 3D electromagnetic simulations show a uniform flux density distribution in the specimen with a variation of 0.03 T and a maximum average induction level of 1.5 T. The developed design has been prototyped, and measurements were carried out using a steel sample of grade 35WW300. Measurements show that applying small mechanical stresses normal to the sample thickness rises the delivered core losses, then the losses decrease continuously as the stress increases. However, the drop in core losses at high stresses does not go lower than the free-stress condition. Physical explanations for the observed trend of core losses as a function of stress are provided based on core loss separation to the hysteresis and eddy current loss components. The experimental results show that the effect of axial compressive stress on magnetic properties of electrical steel at high level of inductions becomes less pronounced.

  7. Normality in Analytical Psychology

    Directory of Open Access Journals (Sweden)

    Steve Myers

    2013-11-01

    Full Text Available Although C.G. Jung’s interest in normality wavered throughout his career, it was one of the areas he identified in later life as worthy of further research. He began his career using a definition of normality which would have been the target of Foucault’s criticism, had Foucault chosen to review Jung’s work. However, Jung then evolved his thinking to a standpoint that was more aligned to Foucault’s own. Thereafter, the post Jungian concept of normality has remained relatively undeveloped by comparison with psychoanalysis and mainstream psychology. Jung’s disjecta membra on the subject suggest that, in contemporary analytical psychology, too much focus is placed on the process of individuation to the neglect of applications that consider collective processes. Also, there is potential for useful research and development into the nature of conflict between individuals and societies, and how normal people typically develop in relation to the spectrum between individuation and collectivity.

  8. Medically-enhanced normality

    DEFF Research Database (Denmark)

    Møldrup, Claus; Traulsen, Janine Morgall; Almarsdóttir, Anna Birna

    2003-01-01

    Objective: To consider public perspectives on the use of medicines for non-medical purposes, a usage called medically-enhanced normality (MEN). Method: Examples from the literature were combined with empirical data derived from two Danish research projects: a Delphi internet study and a Telebus...

  9. The Normal Fetal Pancreas.

    Science.gov (United States)

    Kivilevitch, Zvi; Achiron, Reuven; Perlman, Sharon; Gilboa, Yinon

    2017-10-01

    The aim of the study was to assess the sonographic feasibility of measuring the fetal pancreas and its normal development throughout pregnancy. We conducted a cross-sectional prospective study between 19 and 36 weeks' gestation. The study included singleton pregnancies with normal pregnancy follow-up. The pancreas circumference was measured. The first 90 cases were tested to assess feasibility. Two hundred ninety-seven fetuses of nondiabetic mothers were recruited during a 3-year period. The overall satisfactory visualization rate was 61.6%. The intraobserver and interobserver variability had high interclass correlation coefficients of of 0.964 and 0.967, respectively. A cubic polynomial regression described best the correlation of pancreas circumference with gestational age (r = 0.744; P pancreas circumference percentiles for each week of gestation were calculated. During the study period, we detected 2 cases with overgrowth syndrome and 1 case with an annular pancreas. In this study, we assessed the feasibility of sonography for measuring the fetal pancreas and established a normal reference range for the fetal pancreas circumference throughout pregnancy. This database can be helpful when investigating fetomaternal disorders that can involve its normal development. © 2017 by the American Institute of Ultrasound in Medicine.

  10. Objective Bayesianism and the Maximum Entropy Principle

    Directory of Open Access Journals (Sweden)

    Jon Williamson

    2013-09-01

    Full Text Available Objective Bayesian epistemology invokes three norms: the strengths of our beliefs should be probabilities; they should be calibrated to our evidence of physical probabilities; and they should otherwise equivocate sufficiently between the basic propositions that we can express. The three norms are sometimes explicated by appealing to the maximum entropy principle, which says that a belief function should be a probability function, from all those that are calibrated to evidence, that has maximum entropy. However, the three norms of objective Bayesianism are usually justified in different ways. In this paper, we show that the three norms can all be subsumed under a single justification in terms of minimising worst-case expected loss. This, in turn, is equivalent to maximising a generalised notion of entropy. We suggest that requiring language invariance, in addition to minimising worst-case expected loss, motivates maximisation of standard entropy as opposed to maximisation of other instances of generalised entropy. Our argument also provides a qualified justification for updating degrees of belief by Bayesian conditionalisation. However, conditional probabilities play a less central part in the objective Bayesian account than they do under the subjective view of Bayesianism, leading to a reduced role for Bayes’ Theorem.

  11. Efficient heuristics for maximum common substructure search.

    Science.gov (United States)

    Englert, Péter; Kovács, Péter

    2015-05-26

    Maximum common substructure search is a computationally hard optimization problem with diverse applications in the field of cheminformatics, including similarity search, lead optimization, molecule alignment, and clustering. Most of these applications have strict constraints on running time, so heuristic methods are often preferred. However, the development of an algorithm that is both fast enough and accurate enough for most practical purposes is still a challenge. Moreover, in some applications, the quality of a common substructure depends not only on its size but also on various topological features of the one-to-one atom correspondence it defines. Two state-of-the-art heuristic algorithms for finding maximum common substructures have been implemented at ChemAxon Ltd., and effective heuristics have been developed to improve both their efficiency and the relevance of the atom mappings they provide. The implementations have been thoroughly evaluated and compared with existing solutions (KCOMBU and Indigo). The heuristics have been found to greatly improve the performance and applicability of the algorithms. The purpose of this paper is to introduce the applied methods and present the experimental results.

  12. A Study on the Fatigue-Fractured Surface of Normalized SS41 Steel and M.E.F. Dual Phase Steel by an X-ray Diffraction Technique

    International Nuclear Information System (INIS)

    Oh, Sae Wook; Park, Young Chul; Park, Soo Young; Kim, Deug Jin; Hue, Sun Chul

    1996-01-01

    This study verified the relationship between fracture mechanics parameters and X-ray parameters for normalized SS41 steel with homogeneous crystal structure and M.E.F. dual phase steel(martensite encapsulated islands of ferrite). The fatigue crack propagation test were carried out and X-ray diffraction technique was applied to fatigue fractured surface. The change in X-ray parameters(residual stress, half-value breadth) according to the depth of fatigue fractured surface were investigated. The depth of maximum plastic zone, W y , were determined on the basis of the distribution of the half-value breadth for normalized SS41 steel and that of the residual stress for M.E.F. dual phase steel. K max could be estimated by the measurement of W y

  13. Modelling of tension stiffening for normal and high strength concrete

    DEFF Research Database (Denmark)

    Christiansen, Morten Bo; Nielsen, Mogens Peter

    1998-01-01

    form the model is extended to apply to biaxial stress fields as well. To determine the biaxial stress field, the theorem of minimum complementary elastic energy is used. The theory has been compared with tests on rods, disks, and beams of both normal and high strength concrete, and very good results...

  14. Multiaxial Stress-Strain Modeling and Effect of Additional Hardening due to Nonproportional Loading

    International Nuclear Information System (INIS)

    Rashed, G.; Ghajar, R.; Farrahi, G.

    2007-01-01

    Most engineering components are subjected to multiaxial rather than uniaxial cyclic loading, which causes multiaxial fatigue. The pre-requisite to predict the fatigue life of such components is to determine the multiaxial stress strain relationship. In this paper the multiaxial cyclic stress-strain model under proportional loading is derived using the modified power law stress-strain relationship. The equivalent strain amplitude consisted of the normal strain excursion and maximum shear strain amplitude is used in the proportional model to include the additional hardening effect due to nonproportional loading. Therefore a new multiaxial cyclic stress-strain relationship is devised for out of phase nonproportional loading. The model is applied to the nonproportional loading case and the results are compared with the other researchers' experimental data published in the literature, which are in a reasonable agreement with the experimental data. The relationship presented here is convenient for the engineering applications

  15. 3D geomechanical modeling and numerical simulation of in-situ stress fields in shale reservoirs: A case study of the lower Cambrian Niutitang formation in the Cen'gong block, South China

    Science.gov (United States)

    Liu, Jingshou; Ding, Wenlong; Yang, Haimeng; Wang, Ruyue; Yin, Shuai; Li, Ang; Fu, Fuquan

    2017-08-01

    An analysis of the in-situ state of stress in a shale reservoir was performed based on comprehensive information about the subsurface properties from wellbores established during the development of an oil and gas field. Industrial-level shale gas production has occurred in the Niutitang formation of the lower Cambrian Cen'gong block, South China. In this study, data obtained from hydraulic fracturing, drilling-induced fractures, borehole breakout, global positioning system (GPS), and well deviation statistics have been used to determine the orientation of the maximum horizontal principal stress. Additionally, hydraulic fracturing and multi-pole array acoustic logging (XMAC) were used to determine the vertical variations in the in-situ stress magnitude. Based on logging interpretation and mechanical experiments, the spatial distributions of mechanical parameters were obtained by seismic inversion, and a 3D heterogeneous geomechanical model was established using a finite element stress analysis approach to simulate the in-situ stress fields. The effects of depth, faults, rock mechanics, and layer variations on the principal stresses, horizontal stress difference (Δσ), horizontal stress difference coefficient (Kh), and stress type coefficient (Sp) were determined. The results show that the direction of the maximum principal stress is ESE 120°. Additionally, the development zones of natural fractures appear to correlate with regions with high principal stress differences. At depths shallower than 375 m, the stress type is mainly a thrust faulting stress regime. At depths ranging from 375 to 950 m, the stress type is mainly a strike-slip faulting stress regime. When the depth is > 950 m, the stress type is mainly a normal faulting stress regime. Depth, fault orientation, and rock mechanics all affect the type of stress. The knowledge regarding the Cen'gong block is reliable and can improve borehole stability, casing set point determination, well deployment

  16. Helicon normal modes in Proto-MPEX

    Science.gov (United States)

    Piotrowicz, P. A.; Caneses, J. F.; Green, D. L.; Goulding, R. H.; Lau, C.; Caughman, J. B. O.; Rapp, J.; Ruzic, D. N.

    2018-05-01

    The Proto-MPEX helicon source has been operating in a high electron density ‘helicon-mode’. Establishing plasma densities and magnetic field strengths under the antenna that allow for the formation of normal modes of the fast-wave are believed to be responsible for the ‘helicon-mode’. A 2D finite-element full-wave model of the helicon antenna on Proto-MPEX is used to identify the fast-wave normal modes responsible for the steady-state electron density profile produced by the source. We also show through the simulation that in the regions of operation in which core power deposition is maximum the slow-wave does not deposit significant power besides directly under the antenna. In the case of a simulation where a normal mode is not excited significant edge power is deposited in the mirror region. ).

  17. Manage Stress

    Science.gov (United States)

    ... Manage Stress Print This Topic En español Manage Stress Browse Sections The Basics Overview Signs and Health ... and Health Effects What are the signs of stress? When people are under stress, they may feel: ...

  18. Stress Incontinence

    Science.gov (United States)

    Stress incontinence Overview Urinary incontinence is the unintentional loss of urine. Stress incontinence happens when physical movement or activity — such ... coughing, sneezing, running or heavy lifting — puts pressure (stress) on your bladder. Stress incontinence is not related ...

  19. Genetic Analysis of Relative Cell Injury Percentage and Some Yield Contributing Traits in Wheat Under Nomral and Heat Stress Conditions Análisis Genético del Porcentaje Relativo de Daño celular y algún Rasgo que Contribuye al Rendimiento en Trigo bajo Condiciones Normales y de Estrés Térmico

    Directory of Open Access Journals (Sweden)

    Jehanzeb Farooq

    2011-12-01

    Full Text Available Several wheat genotypes were screened against heat stress. Seven wheat (Triticum aestivum L. cultivars obtained after screening against heat classified as tolerant, moderately tolerant, and susceptible to heat stress, were mated in a complete diallel mating system to study the inheritance pattern of relative cell injury percentage (cell injury % and some yield contributing parameters under normal and heat stress conditions. Significant genotypic differences were found (P Varios genotipos de trigo se discriminaron para estrés térmico. De ellos siete cultivares de trigo (Triticum aestivum L. incluyendo tolerantes, moderadamente tolerantes, y susceptibles a estrés térmico obtenidos después de discriminar con calor se aparearon en un sistema de apareamiento de dialelo completo para estudiar el patrón de heredabilidad del porcentaje de daño celular relativo (daño celular % y algunos parámetros que contribuyen al rendimiento bajo condiciones normales o de estrés térmico. Se encontraron diferencias genotípicas significativas (P < 0.01 para todos los rasgos estudiados bajo ambas condiciones. Pruebas de ajuste revelaron adecuación parcial para rasgos como días a espigadura y días a madurez en ambas condiciones pero mostraron suficiencia completa para área hoja bandera y daño celular % en ambas condiciones. El modelo para producción de grano por planta y biomasa por planta fue completamente suficiente bajo condiciones normales y completamente adecuado en estrés. El componente aditivo de variación genotípica (D fue significativo para todos los rasgos estudiados y más que los componentes de dominancia H1 y H2. Los valores de la proporción de genes con efectos positivos y negativos en los progenitores (H2/4H1 demostraron distribución desigual de genes dominantes en los progenitores para casi todos los rasgos excepto área de hoja bandera, producción de grano, y daño celular % en ambas condiciones. Se encontraron estimaciones

  20. Hydraulic Limits on Maximum Plant Transpiration

    Science.gov (United States)

    Manzoni, S.; Vico, G.; Katul, G. G.; Palmroth, S.; Jackson, R. B.; Porporato, A. M.

    2011-12-01

    Photosynthesis occurs at the expense of water losses through transpiration. As a consequence of this basic carbon-water interaction at the leaf level, plant growth and ecosystem carbon exchanges are tightly coupled to transpiration. In this contribution, the hydraulic constraints that limit transpiration rates under well-watered conditions are examined across plant functional types and climates. The potential water flow through plants is proportional to both xylem hydraulic conductivity (which depends on plant carbon economy) and the difference in water potential between the soil and the atmosphere (the driving force that pulls water from the soil). Differently from previous works, we study how this potential flux changes with the amplitude of the driving force (i.e., we focus on xylem properties and not on stomatal regulation). Xylem hydraulic conductivity decreases as the driving force increases due to cavitation of the tissues. As a result of this negative feedback, more negative leaf (and xylem) water potentials would provide a stronger driving force for water transport, while at the same time limiting xylem hydraulic conductivity due to cavitation. Here, the leaf water potential value that allows an optimum balance between driving force and xylem conductivity is quantified, thus defining the maximum transpiration rate that can be sustained by the soil-to-leaf hydraulic system. To apply the proposed framework at the global scale, a novel database of xylem conductivity and cavitation vulnerability across plant types and biomes is developed. Conductivity and water potential at 50% cavitation are shown to be complementary (in particular between angiosperms and conifers), suggesting a tradeoff between transport efficiency and hydraulic safety. Plants from warmer and drier biomes tend to achieve larger maximum transpiration than plants growing in environments with lower atmospheric water demand. The predicted maximum transpiration and the corresponding leaf water

  1. Analogue of Pontryagin's maximum principle for multiple integrals minimization problems

    OpenAIRE

    Mikhail, Zelikin

    2016-01-01

    The theorem like Pontryagin's maximum principle for multiple integrals is proved. Unlike the usual maximum principle, the maximum should be taken not over all matrices, but only on matrices of rank one. Examples are given.

  2. Lake Basin Fetch and Maximum Length/Width

    Data.gov (United States)

    Minnesota Department of Natural Resources — Linear features representing the Fetch, Maximum Length and Maximum Width of a lake basin. Fetch, maximum length and average width are calcuated from the lake polygon...

  3. Acromioclavicular joint: Normal variation and the diagnosis of dislocation

    Energy Technology Data Exchange (ETDEWEB)

    Keats, T.E.; Pope, T.L. Jr.

    1988-04-01

    Acromioclavicular separation is a common traumatic injury. Diagnosis rests on clinical and radiographic findings. However, normal variation in the alignment of the acromioclavicular joint may make the roentgen diagnosis more difficult. We stress the variations of normal alignment at the acromioclavicular joint and offer suggestions for avoiding pitfalls in this clinical situation.

  4. The acromioclavicular joint: Normal variation and the diagnosis of dislocation

    International Nuclear Information System (INIS)

    Keats, T.E.; Pope, T.L. Jr.

    1988-01-01

    Acromioclavicular separation is a common traumatic injury. Diagnosis rests on clinical and radiographic findings. However, normal variation in the alignment of the acromioclavicular joint may make the roentgen diagnosis more difficult. We stress the variations of normal alignment at the acromioclavicular joint and offer suggestions for avoiding pitfalls in this clinical situation. (orig.)

  5. Maximum Likelihood Reconstruction for Magnetic Resonance Fingerprinting.

    Science.gov (United States)

    Zhao, Bo; Setsompop, Kawin; Ye, Huihui; Cauley, Stephen F; Wald, Lawrence L

    2016-08-01

    This paper introduces a statistical estimation framework for magnetic resonance (MR) fingerprinting, a recently proposed quantitative imaging paradigm. Within this framework, we present a maximum likelihood (ML) formalism to estimate multiple MR tissue parameter maps directly from highly undersampled, noisy k-space data. A novel algorithm, based on variable splitting, the alternating direction method of multipliers, and the variable projection method, is developed to solve the resulting optimization problem. Representative results from both simulations and in vivo experiments demonstrate that the proposed approach yields significantly improved accuracy in parameter estimation, compared to the conventional MR fingerprinting reconstruction. Moreover, the proposed framework provides new theoretical insights into the conventional approach. We show analytically that the conventional approach is an approximation to the ML reconstruction; more precisely, it is exactly equivalent to the first iteration of the proposed algorithm for the ML reconstruction, provided that a gridding reconstruction is used as an initialization.

  6. Maximum Profit Configurations of Commercial Engines

    Directory of Open Access Journals (Sweden)

    Yiran Chen

    2011-06-01

    Full Text Available An investigation of commercial engines with finite capacity low- and high-price economic subsystems and a generalized commodity transfer law [n ∝ Δ (P m] in commodity flow processes, in which effects of the price elasticities of supply and demand are introduced, is presented in this paper. Optimal cycle configurations of commercial engines for maximum profit are obtained by applying optimal control theory. In some special cases, the eventual state—market equilibrium—is solely determined by the initial conditions and the inherent characteristics of two subsystems; while the different ways of transfer affect the model in respects of the specific forms of the paths of prices and the instantaneous commodity flow, i.e., the optimal configuration.

  7. The worst case complexity of maximum parsimony.

    Science.gov (United States)

    Carmel, Amir; Musa-Lempel, Noa; Tsur, Dekel; Ziv-Ukelson, Michal

    2014-11-01

    One of the core classical problems in computational biology is that of constructing the most parsimonious phylogenetic tree interpreting an input set of sequences from the genomes of evolutionarily related organisms. We reexamine the classical maximum parsimony (MP) optimization problem for the general (asymmetric) scoring matrix case, where rooted phylogenies are implied, and analyze the worst case bounds of three approaches to MP: The approach of Cavalli-Sforza and Edwards, the approach of Hendy and Penny, and a new agglomerative, "bottom-up" approach we present in this article. We show that the second and third approaches are faster than the first one by a factor of Θ(√n) and Θ(n), respectively, where n is the number of species.

  8. Maximum T/sub c/: optimistic evidence

    International Nuclear Information System (INIS)

    Dynes, R.C.; Allen, P.B.

    1976-01-01

    A reanalysis of Eliashberg theory in the strong coupling limit and the relationship between the superconducting transition temperature T/sub c/ of a material and its normal state properties is presented. At weak and intermediate coupling (lambda approx. 2 >)/sup 1 / 2 /. The lambda = 2 limit predicted by McMillan disappears in the correct theory because it is a result of the functional dependence of T/sub c/ on lambda and used by McMillan which is valid only if lamba 2 (ω)F(ω) for values of lambda < or = 1.5

  9. Modelling maximum likelihood estimation of availability

    International Nuclear Information System (INIS)

    Waller, R.A.; Tietjen, G.L.; Rock, G.W.

    1975-01-01

    Suppose the performance of a nuclear powered electrical generating power plant is continuously monitored to record the sequence of failure and repairs during sustained operation. The purpose of this study is to assess one method of estimating the performance of the power plant when the measure of performance is availability. That is, we determine the probability that the plant is operational at time t. To study the availability of a power plant, we first assume statistical models for the variables, X and Y, which denote the time-to-failure and the time-to-repair variables, respectively. Once those statistical models are specified, the availability, A(t), can be expressed as a function of some or all of their parameters. Usually those parameters are unknown in practice and so A(t) is unknown. This paper discusses the maximum likelihood estimator of A(t) when the time-to-failure model for X is an exponential density with parameter, lambda, and the time-to-repair model for Y is an exponential density with parameter, theta. Under the assumption of exponential models for X and Y, it follows that the instantaneous availability at time t is A(t)=lambda/(lambda+theta)+theta/(lambda+theta)exp[-[(1/lambda)+(1/theta)]t] with t>0. Also, the steady-state availability is A(infinity)=lambda/(lambda+theta). We use the observations from n failure-repair cycles of the power plant, say X 1 , X 2 , ..., Xsub(n), Y 1 , Y 2 , ..., Ysub(n) to present the maximum likelihood estimators of A(t) and A(infinity). The exact sampling distributions for those estimators and some statistical properties are discussed before a simulation model is used to determine 95% simulation intervals for A(t). The methodology is applied to two examples which approximate the operating history of two nuclear power plants. (author)

  10. Idiopathic Normal Pressure Hydrocephalus

    Directory of Open Access Journals (Sweden)

    Basant R. Nassar BS

    2016-04-01

    Full Text Available Idiopathic normal pressure hydrocephalus (iNPH is a potentially reversible neurodegenerative disease commonly characterized by a triad of dementia, gait, and urinary disturbance. Advancements in diagnosis and treatment have aided in properly identifying and improving symptoms in patients. However, a large proportion of iNPH patients remain either undiagnosed or misdiagnosed. Using PubMed search engine of keywords “normal pressure hydrocephalus,” “diagnosis,” “shunt treatment,” “biomarkers,” “gait disturbances,” “cognitive function,” “neuropsychology,” “imaging,” and “pathogenesis,” articles were obtained for this review. The majority of the articles were retrieved from the past 10 years. The purpose of this review article is to aid general practitioners in further understanding current findings on the pathogenesis, diagnosis, and treatment of iNPH.

  11. Normal Weight Dyslipidemia

    DEFF Research Database (Denmark)

    Ipsen, David Hojland; Tveden-Nyborg, Pernille; Lykkesfeldt, Jens

    2016-01-01

    Objective: The liver coordinates lipid metabolism and may play a vital role in the development of dyslipidemia, even in the absence of obesity. Normal weight dyslipidemia (NWD) and patients with nonalcoholic fatty liver disease (NAFLD) who do not have obesity constitute a unique subset...... of individuals characterized by dyslipidemia and metabolic deterioration. This review examined the available literature on the role of the liver in dyslipidemia and the metabolic characteristics of patients with NAFLD who do not have obesity. Methods: PubMed was searched using the following keywords: nonobese......, dyslipidemia, NAFLD, NWD, liver, and metabolically obese/unhealthy normal weight. Additionally, article bibliographies were screened, and relevant citations were retrieved. Studies were excluded if they had not measured relevant biomarkers of dyslipidemia. Results: NWD and NAFLD without obesity share a similar...

  12. Stressed podocytes

    DEFF Research Database (Denmark)

    Svenningsen, Per

    2015-01-01

    and in response to injury induced by endoplasmatic reticulum (ER) stress (Golubinskaya et al., 2015). Their report shed light on the complex regulation of Best3 in podocytes and will help pave the way for future studies on the pathogenesis of kidneys diseases with podocyte injury. This article is protected...... structure appears to be a common finding in acquired proteinuric conditions (Pavenstadt et al., 2003). Identification of genes that are involved in physiological and pathophysiological functions of the podocytes is a major task. Recent studies indicate that Bestrophin (Best) 3 has cell protective functions...... in a number of cell types (Lee et al., 2012, Jiang et al., 2013, Song et al., 2014). In the present issue of Acta Physiologica, Golubinskaya et al. use cultured podocytes, kidneys and isolated glomeruli of the mouse kidney to provide a thorough characterisation of Best3 expression under normal conditions...

  13. Ethics and "normal birth".

    Science.gov (United States)

    Lyerly, Anne Drapkin

    2012-12-01

    The concept of "normal birth" has been promoted as ideal by several international organizations, although debate about its meaning is ongoing. In this article, I examine the concept of normalcy to explore its ethical implications and raise a trio of concerns. First, in its emphasis on nonuse of technology as a goal, the concept of normalcy may marginalize women for whom medical intervention is necessary or beneficial. Second, in its emphasis on birth as a socially meaningful event, the mantra of normalcy may unintentionally avert attention to meaning in medically complicated births. Third, the emphasis on birth as a normal and healthy event may be a contributor to the long-standing tolerance for the dearth of evidence guiding the treatment of illness during pregnancy and the failure to responsibly and productively engage pregnant women in health research. Given these concerns, it is worth debating not just what "normal birth" means, but whether the term as an ideal earns its keep. © 2012, Copyright the Authors Journal compilation © 2012, Wiley Periodicals, Inc.

  14. Distribution of Snow and Maximum Snow Water Equivalent Obtained by LANDSAT Data and Degree Day Method

    Science.gov (United States)

    Takeda, K.; Ochiai, H.; Takeuchi, S.

    1985-01-01

    Maximum snow water equivalence and snowcover distribution are estimated using several LANDSAT data taken in snowmelting season over a four year period. The test site is Okutadami-gawa Basin located in the central position of Tohoku-Kanto-Chubu District. The year to year normalization for snowmelt volume computation on the snow line is conducted by year to year correction of degree days using the snowcover percentage within the test basin obtained from LANDSAT data. The maximum snow water equivalent map in the test basin is generated based on the normalized snowmelt volume on the snow line extracted from four LANDSAT data taken in a different year. The snowcover distribution on an arbitrary day in snowmelting of 1982 is estimated from the maximum snow water equivalent map. The estimated snowcover is compared with the snowcover area extracted from NOAA-AVHRR data taken on the same day. The applicability of the snow estimation using LANDSAT data is discussed.

  15. Stochastic modelling of the monthly average maximum and minimum temperature patterns in India 1981-2015

    Science.gov (United States)

    Narasimha Murthy, K. V.; Saravana, R.; Vijaya Kumar, K.

    2018-04-01

    The paper investigates the stochastic modelling and forecasting of monthly average maximum and minimum temperature patterns through suitable seasonal auto regressive integrated moving average (SARIMA) model for the period 1981-2015 in India. The variations and distributions of monthly maximum and minimum temperatures are analyzed through Box plots and cumulative distribution functions. The time series plot indicates that the maximum temperature series contain sharp peaks in almost all the years, while it is not true for the minimum temperature series, so both the series are modelled separately. The possible SARIMA model has been chosen based on observing autocorrelation function (ACF), partial autocorrelation function (PACF), and inverse autocorrelation function (IACF) of the logarithmic transformed temperature series. The SARIMA (1, 0, 0) × (0, 1, 1)12 model is selected for monthly average maximum and minimum temperature series based on minimum Bayesian information criteria. The model parameters are obtained using maximum-likelihood method with the help of standard error of residuals. The adequacy of the selected model is determined using correlation diagnostic checking through ACF, PACF, IACF, and p values of Ljung-Box test statistic of residuals and using normal diagnostic checking through the kernel and normal density curves of histogram and Q-Q plot. Finally, the forecasting of monthly maximum and minimum temperature patterns of India for the next 3 years has been noticed with the help of selected model.

  16. Tectonic stress orientations and magnitudes, and friction of faults, deduced from earthquake focal mechanism inversions over the Korean Peninsula

    Science.gov (United States)

    Soh, Inho; Chang, Chandong; Lee, Junhyung; Hong, Tae-Kyung; Park, Eui-Seob

    2018-05-01

    We characterize the present-day stress state in and around the Korean Peninsula using formal inversions of earthquake focal mechanisms. Two different methods are used to select preferred fault planes in the double-couple focal mechanism solutions: one that minimizes average misfit angle and the other choosing faults with higher instability. We invert selected sets of fault planes for estimating the principal stresses at regularly spaced grid points, using a circular-area data-binning method, where the bin radius is optimized to yield the best possible stress inversion results based on the World Stress Map quality ranking scheme. The inversions using the two methods yield well constrained and fairly comparable results, which indicate that the prevailing stress regime is strike-slip, and the maximum horizontal principal stress (SHmax) is oriented ENE-WSW throughout the study region. Although the orientation of the stresses is consistent across the peninsula, the relative stress magnitude parameter (R-value) varies significantly, from 0.22 in the northwest to 0.89 in the southeast. Based on our knowledge of the R-values and stress regime, and using a value for vertical stress (Sv) estimated from the overburden weight of rock, together with a value for the maximum differential stress (based on the Coulomb friction of faults optimally oriented for slip), we estimate the magnitudes of the two horizontal principal stresses. The horizontal stress magnitudes increase from west to east such that SHmax/Sv ratio rises from 1.5 to 2.4, and the Shmin/Sv ratio from 0.6 to 0.8. The variation in the magnitudes of the tectonic stresses appears to be related to differences in the rigidity of crustal rocks. Using the complete stress tensors, including both orientations and magnitudes, we assess the possible ranges of frictional coefficients for different types of faults. We show that normal and reverse faults have lower frictional coefficients than strike-slip faults, suggesting that

  17. Relationship between screw sagittal angle and stress on endplate of adjacent segments after anterior cervical corpectomy and fusion with internal fixation: a Chinese finite element study.

    Science.gov (United States)

    Zhang, Yu; Tang, Yibo; Shen, Hongxing

    2017-12-01

    In order to reduce the incidence of adjacent segment disease (ASD), the current study was designed to establish Chinese finite element models of normal 3rd~7th cervical vertebrae (C3-C7) and anterior cervical corpectomy and fusion (ACCF) with internal fixation , and analyze the influence of screw sagittal angle (SSA) on stress on endplate of adjacent cervical segments. Mimics 8.1 and Abaqus/CAE 6.10 softwares were adopted to establish finite element models. For C4 superior endplate and C6 inferior endplate, their anterior areas had the maximum stress in anteflexion position, and their posterior areas had the maximum stress in posterior extension position. As SSA increased, the stress reduced. With an increase of 10° in SSA, the stress on anterior areas of C4 superior endplate and C6 inferior endplate reduced by 12.67% and 7.99% in anteflexion position, respectively. With an increase of 10° in SSA, the stress on posterior areas of C4 superior endplate and C6 inferior endplate reduced by 9.68% and 10.22% in posterior extension position, respectively. The current study established Chinese finite element models of normal C3-C7 and ACCF with internal fixation , and demonstrated that as SSA increased, the stress on endplate of adjacent cervical segments decreased. In clinical surgery, increased SSA is able to play important role in protecting the adjacent cervical segments and reducing the incidence of ASD.

  18. A maximum power point tracking for photovoltaic-SPE system using a maximum current controller

    Energy Technology Data Exchange (ETDEWEB)

    Muhida, Riza [Osaka Univ., Dept. of Physical Science, Toyonaka, Osaka (Japan); Osaka Univ., Dept. of Electrical Engineering, Suita, Osaka (Japan); Park, Minwon; Dakkak, Mohammed; Matsuura, Kenji [Osaka Univ., Dept. of Electrical Engineering, Suita, Osaka (Japan); Tsuyoshi, Akira; Michira, Masakazu [Kobe City College of Technology, Nishi-ku, Kobe (Japan)

    2003-02-01

    Processes to produce hydrogen from solar photovoltaic (PV)-powered water electrolysis using solid polymer electrolysis (SPE) are reported. An alternative control of maximum power point tracking (MPPT) in the PV-SPE system based on the maximum current searching methods has been designed and implemented. Based on the characteristics of voltage-current and theoretical analysis of SPE, it can be shown that the tracking of the maximum current output of DC-DC converter in SPE side will track the MPPT of photovoltaic panel simultaneously. This method uses a proportional integrator controller to control the duty factor of DC-DC converter with pulse-width modulator (PWM). The MPPT performance and hydrogen production performance of this method have been evaluated and discussed based on the results of the experiment. (Author)

  19. Padrões de deficiência hídrica para a cultura de milho (safra normal e safrinha no estado de Goiás e suas conseqüencias para o melhoramento genético Water stress pattern for corn (first and second crop in the Goiás State and their consequences for the breeding program

    Directory of Open Access Journals (Sweden)

    Alexandre Bryan Heinemann

    2009-08-01

    Full Text Available Deficiência hídrica é considerada a maior restrição na produção e estabilidade da produtividade de culturas em muitas regiões do mundo. No Estado de Goiás, região na qual predomina a produção em sequeiro, para a cultura do milho (Zea mays L. implantada na safra normal e na safrinha, é comum sofrer períodos de estresse por deficiência hídrica intermitente ou terminal, que reduzem o rendimento de grãos. No processo de desenvolvimento de novos híbridos e variedades cultivadas, genótipos são selecionados em função de sua adaptabilidade em um determinado ambiente alvo. Assim, programas de melhoramento vegetal, com o objetivo de desenvolver híbridos e variedades cultivadas mais adaptados a um determinado ambiente, requerem informações sob a probabilidade de ocorrência dos diferentes tipos de deficiência hídrica, como também, suas características, intensidade e tempo, em função da fase fenológica da cultura. Um modelo de simulação de culturas foi utilizado para determinar os padrões de deficiência hídrica no estado de Goiás, considerando 12 locais e 6 diferentes datas de semeadura para a cultura do milho semeada na safra normal e na safrinha. Para a cultura do milho semeado na safra normal, a perda na produtividade decorrente do estresse por deficiência hídrica foi menor que 50%, sendo que os tipos de deficiência hídrica que provocam um maior impacto na produtividade iniciam-se no começo do período reprodutivo. Para o milho semeado na safrinha, a perda na produtividade é superior a 50%, sendo mais comum o estresse terminal, que tem sua maior intensidade no enchimento de grãos.Water stress is a major constraint to crop production and yield stability in many regions of the world. The cultivation of corn (Zea mays L. in the Brazilian State of Goiás, is frequent affected by periods of water stress resulting in yield reduction. During the process of developing new hybrids and cultivated varieties, new

  20. Maximum permissible concentrations of uranium in air

    CERN Document Server

    Adams, N

    1973-01-01

    The retention of uranium by bone and kidney has been re-evaluated taking account of recently published data for a man who had been occupationally exposed to natural uranium aerosols and for adults who had ingested uranium at the normal dietary levels. For life-time occupational exposure to uranium aerosols the new retention functions yield a greater retention in bone and a smaller retention in kidney than the earlier ones, which were based on acute intakes of uranium by terminal patients. Hence bone replaces kidney as the critical organ. The (MPC) sub a for uranium 238 on radiological considerations using the current (1959) ICRP lung model for the new retention functions is slightly smaller than for earlier functions but the (MPC) sub a determined by chemical toxicity remains the most restrictive.

  1. [The maximum heart rate in the exercise test: the 220-age formula or Sheffield's table?].

    Science.gov (United States)

    Mesquita, A; Trabulo, M; Mendes, M; Viana, J F; Seabra-Gomes, R

    1996-02-01

    To determine in the maximum cardiac rate in exercise test of apparently healthy individuals may be more properly estimated through 220-age formula (Astrand) or the Sheffield table. Retrospective analysis of clinical history and exercises test of apparently healthy individuals submitted to cardiac check-up. Sequential sampling of 170 healthy individuals submitted to cardiac check-up between April 1988 and September 1992. Comparison of maximum cardiac rate of individuals studied by the protocols of Bruce and modified Bruce, in interrupted exercise test by fatigue, and with the estimated values by the formulae: 220-age versus Sheffield table. The maximum cardiac heart rate is similar with both protocols. This parameter in normal individuals is better predicted by the 220-age formula. The theoretic maximum cardiac heart rate determined by 220-age formula should be recommended for a healthy, and for this reason the Sheffield table has been excluded from our clinical practice.

  2. Maximum mass of magnetic white dwarfs

    International Nuclear Information System (INIS)

    Paret, Daryel Manreza; Horvath, Jorge Ernesto; Martínez, Aurora Perez

    2015-01-01

    We revisit the problem of the maximum masses of magnetized white dwarfs (WDs). The impact of a strong magnetic field on the structure equations is addressed. The pressures become anisotropic due to the presence of the magnetic field and split into parallel and perpendicular components. We first construct stable solutions of the Tolman-Oppenheimer-Volkoff equations for parallel pressures and find that physical solutions vanish for the perpendicular pressure when B ≳ 10 13 G. This fact establishes an upper bound for a magnetic field and the stability of the configurations in the (quasi) spherical approximation. Our findings also indicate that it is not possible to obtain stable magnetized WDs with super-Chandrasekhar masses because the values of the magnetic field needed for them are higher than this bound. To proceed into the anisotropic regime, we can apply results for structure equations appropriate for a cylindrical metric with anisotropic pressures that were derived in our previous work. From the solutions of the structure equations in cylindrical symmetry we have confirmed the same bound for B ∼ 10 13 G, since beyond this value no physical solutions are possible. Our tentative conclusion is that massive WDs with masses well beyond the Chandrasekhar limit do not constitute stable solutions and should not exist. (paper)

  3. TRENDS IN ESTIMATED MIXING DEPTH DAILY MAXIMUMS

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R; Amy DuPont, A; Robert Kurzeja, R; Matt Parker, M

    2007-11-12

    Mixing depth is an important quantity in the determination of air pollution concentrations. Fireweather forecasts depend strongly on estimates of the mixing depth as a means of determining the altitude and dilution (ventilation rates) of smoke plumes. The Savannah River United States Forest Service (USFS) routinely conducts prescribed fires at the Savannah River Site (SRS), a heavily wooded Department of Energy (DOE) facility located in southwest South Carolina. For many years, the Savannah River National Laboratory (SRNL) has provided forecasts of weather conditions in support of the fire program, including an estimated mixing depth using potential temperature and turbulence change with height at a given location. This paper examines trends in the average estimated mixing depth daily maximum at the SRS over an extended period of time (4.75 years) derived from numerical atmospheric simulations using two versions of the Regional Atmospheric Modeling System (RAMS). This allows for differences to be seen between the model versions, as well as trends on a multi-year time frame. In addition, comparisons of predicted mixing depth for individual days in which special balloon soundings were released are also discussed.

  4. Maximum Margin Clustering of Hyperspectral Data

    Science.gov (United States)

    Niazmardi, S.; Safari, A.; Homayouni, S.

    2013-09-01

    In recent decades, large margin methods such as Support Vector Machines (SVMs) are supposed to be the state-of-the-art of supervised learning methods for classification of hyperspectral data. However, the results of these algorithms mainly depend on the quality and quantity of available training data. To tackle down the problems associated with the training data, the researcher put effort into extending the capability of large margin algorithms for unsupervised learning. One of the recent proposed algorithms is Maximum Margin Clustering (MMC). The MMC is an unsupervised SVMs algorithm that simultaneously estimates both the labels and the hyperplane parameters. Nevertheless, the optimization of the MMC algorithm is a non-convex problem. Most of the existing MMC methods rely on the reformulating and the relaxing of the non-convex optimization problem as semi-definite programs (SDP), which are computationally very expensive and only can handle small data sets. Moreover, most of these algorithms are two-class classification, which cannot be used for classification of remotely sensed data. In this paper, a new MMC algorithm is used that solve the original non-convex problem using Alternative Optimization method. This algorithm is also extended for multi-class classification and its performance is evaluated. The results of the proposed algorithm show that the algorithm has acceptable results for hyperspectral data clustering.

  5. Paving the road to maximum productivity.

    Science.gov (United States)

    Holland, C

    1998-01-01

    "Job security" is an oxymoron in today's environment of downsizing, mergers, and acquisitions. Workers find themselves living by new rules in the workplace that they may not understand. How do we cope? It is the leader's charge to take advantage of this chaos and create conditions under which his or her people can understand the need for change and come together with a shared purpose to effect that change. The clinical laboratory at Arkansas Children's Hospital has taken advantage of this chaos to down-size and to redesign how the work gets done to pave the road to maximum productivity. After initial hourly cutbacks, the workers accepted the cold, hard fact that they would never get their old world back. They set goals to proactively shape their new world through reorganizing, flexing staff with workload, creating a rapid response laboratory, exploiting information technology, and outsourcing. Today the laboratory is a lean, productive machine that accepts change as a way of life. We have learned to adapt, trust, and support each other as we have journeyed together over the rough roads. We are looking forward to paving a new fork in the road to the future.

  6. Maximum likelihood window for time delay estimation

    International Nuclear Information System (INIS)

    Lee, Young Sup; Yoon, Dong Jin; Kim, Chi Yup

    2004-01-01

    Time delay estimation for the detection of leak location in underground pipelines is critically important. Because the exact leak location depends upon the precision of the time delay between sensor signals due to leak noise and the speed of elastic waves, the research on the estimation of time delay has been one of the key issues in leak lovating with the time arrival difference method. In this study, an optimal Maximum Likelihood window is considered to obtain a better estimation of the time delay. This method has been proved in experiments, which can provide much clearer and more precise peaks in cross-correlation functions of leak signals. The leak location error has been less than 1 % of the distance between sensors, for example the error was not greater than 3 m for 300 m long underground pipelines. Apart from the experiment, an intensive theoretical analysis in terms of signal processing has been described. The improved leak locating with the suggested method is due to the windowing effect in frequency domain, which offers a weighting in significant frequencies.

  7. Ancestral Sequence Reconstruction with Maximum Parsimony.

    Science.gov (United States)

    Herbst, Lina; Fischer, Mareike

    2017-12-01

    One of the main aims in phylogenetics is the estimation of ancestral sequences based on present-day data like, for instance, DNA alignments. One way to estimate the data of the last common ancestor of a given set of species is to first reconstruct a phylogenetic tree with some tree inference method and then to use some method of ancestral state inference based on that tree. One of the best-known methods both for tree inference and for ancestral sequence inference is Maximum Parsimony (MP). In this manuscript, we focus on this method and on ancestral state inference for fully bifurcating trees. In particular, we investigate a conjecture published by Charleston and Steel in 1995 concerning the number of species which need to have a particular state, say a, at a particular site in order for MP to unambiguously return a as an estimate for the state of the last common ancestor. We prove the conjecture for all even numbers of character states, which is the most relevant case in biology. We also show that the conjecture does not hold in general for odd numbers of character states, but also present some positive results for this case.

  8. 20 CFR 226.52 - Total annuity subject to maximum.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Total annuity subject to maximum. 226.52... COMPUTING EMPLOYEE, SPOUSE, AND DIVORCED SPOUSE ANNUITIES Railroad Retirement Family Maximum § 226.52 Total annuity subject to maximum. The total annuity amount which is compared to the maximum monthly amount to...

  9. Half-width at half-maximum, full-width at half-maximum analysis

    Indian Academy of Sciences (India)

    addition to the well-defined parameter full-width at half-maximum (FWHM). The distribution of ... optical side-lobes in the diffraction pattern resulting in steep central maxima [6], reduc- tion of effects of ... and broad central peak. The idea of.

  10. Nuclear stress test

    Science.gov (United States)

    ... Persantine stress test; Thallium stress test; Stress test - nuclear; Adenosine stress test; Regadenoson stress test; CAD - nuclear stress; Coronary artery disease - nuclear stress; Angina - nuclear ...

  11. Cosmic shear measurement with maximum likelihood and maximum a posteriori inference

    Science.gov (United States)

    Hall, Alex; Taylor, Andy

    2017-06-01

    We investigate the problem of noise bias in maximum likelihood and maximum a posteriori estimators for cosmic shear. We derive the leading and next-to-leading order biases and compute them in the context of galaxy ellipticity measurements, extending previous work on maximum likelihood inference for weak lensing. We show that a large part of the bias on these point estimators can be removed using information already contained in the likelihood when a galaxy model is specified, without the need for external calibration. We test these bias-corrected estimators on simulated galaxy images similar to those expected from planned space-based weak lensing surveys, with promising results. We find that the introduction of an intrinsic shape prior can help with mitigation of noise bias, such that the maximum a posteriori estimate can be made less biased than the maximum likelihood estimate. Second-order terms offer a check on the convergence of the estimators, but are largely subdominant. We show how biases propagate to shear estimates, demonstrating in our simple set-up that shear biases can be reduced by orders of magnitude and potentially to within the requirements of planned space-based surveys at mild signal-to-noise ratio. We find that second-order terms can exhibit significant cancellations at low signal-to-noise ratio when Gaussian noise is assumed, which has implications for inferring the performance of shear-measurement algorithms from simplified simulations. We discuss the viability of our point estimators as tools for lensing inference, arguing that they allow for the robust measurement of ellipticity and shear.

  12. Optimal operating conditions for maximum biogas production in anaerobic bioreactors

    International Nuclear Information System (INIS)

    Balmant, W.; Oliveira, B.H.; Mitchell, D.A.; Vargas, J.V.C.; Ordonez, J.C.

    2014-01-01

    The objective of this paper is to demonstrate the existence of optimal residence time and substrate inlet mass flow rate for maximum methane production through numerical simulations performed with a general transient mathematical model of an anaerobic biodigester introduced in this study. It is herein suggested a simplified model with only the most important reaction steps which are carried out by a single type of microorganisms following Monod kinetics. The mathematical model was developed for a well mixed reactor (CSTR – Continuous Stirred-Tank Reactor), considering three main reaction steps: acidogenesis, with a μ max of 8.64 day −1 and a K S of 250 mg/L, acetogenesis, with a μ max of 2.64 day −1 and a K S of 32 mg/L, and methanogenesis, with a μ max of 1.392 day −1 and a K S of 100 mg/L. The yield coefficients were 0.1-g-dry-cells/g-pollymeric compound for acidogenesis, 0.1-g-dry-cells/g-propionic acid and 0.1-g-dry-cells/g-butyric acid for acetogenesis and 0.1 g-dry-cells/g-acetic acid for methanogenesis. The model describes both the transient and the steady-state regime for several different biodigester design and operating conditions. After model experimental validation, a parametric analysis was performed. It was found that biogas production is strongly dependent on the input polymeric substrate and fermentable monomer concentrations, but fairly independent of the input propionic, acetic and butyric acid concentrations. An optimisation study was then conducted and optimal residence time and substrate inlet mass flow rate were found for maximum methane production. The optima found were very sharp, showing a sudden drop of methane mass flow rate variation from the observed maximum to zero, within a 20% range around the optimal operating parameters, which stresses the importance of their identification, no matter how complex the actual bioreactor design may be. The model is therefore expected to be a useful tool for simulation, design, control and

  13. A maximum likelihood framework for protein design

    Directory of Open Access Journals (Sweden)

    Philippe Hervé

    2006-06-01

    Full Text Available Abstract Background The aim of protein design is to predict amino-acid sequences compatible with a given target structure. Traditionally envisioned as a purely thermodynamic question, this problem can also be understood in a wider context, where additional constraints are captured by learning the sequence patterns displayed by natural proteins of known conformation. In this latter perspective, however, we still need a theoretical formalization of the question, leading to general and efficient learning methods, and allowing for the selection of fast and accurate objective functions quantifying sequence/structure compatibility. Results We propose a formulation of the protein design problem in terms of model-based statistical inference. Our framework uses the maximum likelihood principle to optimize the unknown parameters of a statistical potential, which we call an inverse potential to contrast with classical potentials used for structure prediction. We propose an implementation based on Markov chain Monte Carlo, in which the likelihood is maximized by gradient descent and is numerically estimated by thermodynamic integration. The fit of the models is evaluated by cross-validation. We apply this to a simple pairwise contact potential, supplemented with a solvent-accessibility term, and show that the resulting models have a better predictive power than currently available pairwise potentials. Furthermore, the model comparison method presented here allows one to measure the relative contribution of each component of the potential, and to choose the optimal number of accessibility classes, which turns out to be much higher than classically considered. Conclusion Altogether, this reformulation makes it possible to test a wide diversity of models, using different forms of potentials, or accounting for other factors than just the constraint of thermodynamic stability. Ultimately, such model-based statistical analyses may help to understand the forces

  14. Thermal stress and seismogenesis

    International Nuclear Information System (INIS)

    Zhou Huilan; Wei Dongping

    1989-05-01

    In this paper, the Fourier stress method was applied to deal with the problem of plane thermal stress, and a computing formula was given. As an example, we set up a variate temperature field to describe the uplifted upper mantle in Bozhong area of China, and the computing results shows that the maximum value of thermal plane shear stress is up to nearly 7x10 7 P α in two regions of this area. Since the Bohai earthquake (18 July, 1969, M s = 7.4) occurred at the edge of one of them and Tangshan earthquake (28 July, 1976, M s = 7.8) within another, their occurrences can be related reasonably to the thermal stress. (author). 15 refs, 7 figs

  15. Tumor vessel normalization after aerobic exercise enhances chemotherapeutic efficacy.

    Science.gov (United States)

    Schadler, Keri L; Thomas, Nicholas J; Galie, Peter A; Bhang, Dong Ha; Roby, Kerry C; Addai, Prince; Till, Jacob E; Sturgeon, Kathleen; Zaslavsky, Alexander; Chen, Christopher S; Ryeom, Sandra

    2016-10-04

    Targeted therapies aimed at tumor vasculature are utilized in combination with chemotherapy to improve drug delivery and efficacy after tumor vascular normalization. Tumor vessels are highly disorganized with disrupted blood flow impeding drug delivery to cancer cells. Although pharmacologic anti-angiogenic therapy can remodel and normalize tumor vessels, there is a limited window of efficacy and these drugs are associated with severe side effects necessitating alternatives for vascular normalization. Recently, moderate aerobic exercise has been shown to induce vascular normalization in mouse models. Here, we provide a mechanistic explanation for the tumor vascular normalization induced by exercise. Shear stress, the mechanical stimuli exerted on endothelial cells by blood flow, modulates vascular integrity. Increasing vascular shear stress through aerobic exercise can alter and remodel blood vessels in normal tissues. Our data in mouse models indicate that activation of calcineurin-NFAT-TSP1 signaling in endothelial cells plays a critical role in exercise-induced shear stress mediated tumor vessel remodeling. We show that moderate aerobic exercise with chemotherapy caused a significantly greater decrease in tumor growth than chemotherapy alone through improved chemotherapy delivery after tumor vascular normalization. Our work suggests that the vascular normalizing effects of aerobic exercise can be an effective chemotherapy adjuvant.

  16. Theory of normal metals

    International Nuclear Information System (INIS)

    Mahan, G.D.

    1992-01-01

    The organizers requested that I give eight lectures on the theory of normal metals, ''with an eye on superconductivity.'' My job was to cover the general properties of metals. The topics were selected according to what the students would need to known for the following lectures on superconductivity. My role was to prepare the ground work for the later lectures. The problem is that there is not yet a widely accepted theory for the mechanism which pairs the electrons. Many mechanisms have been proposed, with those of phonons and spin fluctuations having the most followers. So I tried to discuss both topics. I also introduced the tight-binding model for metals, which forms the basis for most of the work on the cuprate superconductors

  17. Elasto-plastic deformation and plate weakening due to normal faulting in the subducting plate along the Mariana Trench

    Science.gov (United States)

    Zhou, Zhiyuan; Lin, Jian

    2018-06-01

    We investigated variations in the elasto-plastic deformation of the subducting plate along the Mariana Trench through an analysis of flexural bending and normal fault characteristics together with geodynamic modeling. Most normal faults were initiated at the outer-rise region and grew toward the trench axis with strikes mostly subparallel to the local trench axis. The average trench relief and maximum fault throws were measured to be significantly greater in the southern region (5 km and 320 m, respectively) than the northern and central regions (2 km and 200 m). The subducting plate was modeled as an elasto-plastic slab subjected to tectonic loading at the trench axis. The calculated strain rates and velocities revealed an array of normal fault-like shear zones in the upper plate, resulting in significant faulting-induced reduction in the deviatoric stresses. We then inverted for solutions that best fit the observed flexural bending and normal faulting characteristics, revealing normal fault penetration to depths of 21, 20, and 32 km beneath the seafloor for the northern, central, and southern regions, respectively, which is consistent with the observed depths of the relocated normal faulting earthquakes in the central Mariana Trench. The calculated deeper normal faults of the southern region might lead to about twice as much water being carried into the mantle per unit trench length than the northern and central regions. We further calculated that normal faulting has reduced the effective elastic plate thickness Te by up to 52% locally in the southern region and 33% in both the northern and central regions. The best-fitting solutions revealed a greater apparent angle of the pulling force in the southern region (51-64°) than in the northern (22-35°) and central (20-34°) regions, which correlates with a general southward increase in the seismically-determined dip angle of the subducting slab along the Mariana Trench.

  18. A Piezoelectric Shear Stress Sensor

    Science.gov (United States)

    Kim, Taeyang; Saini, Aditya; Kim, Jinwook; Gopalarathnam, Ashok; Zhu, Yong; Palmieri, Frank L.; Wohl, Christopher J.; Jiang, Xiaoning

    2016-01-01

    In this paper, a piezoelectric sensor with a floating element was developed for shear stress measurement. The piezoelectric sensor was designed to detect the pure shear stress suppressing effects of normal stress generated from the vortex lift-up by applying opposite poling vectors to the: piezoelectric elements. The sensor was first calibrated in the lab by applying shear forces and it showed high sensitivity to shear stress (=91.3 +/- 2.1 pC/Pa) due to the high piezoelectric coefficients of PMN-33%PT (d31=-1330 pC/N). The sensor also showed almost no sensitivity to normal stress (less than 1.2 pC/Pa) because of the electromechanical symmetry of the device. The usable frequency range of the sensor is 0-800 Hz. Keywords: Piezoelectric sensor, shear stress, floating element, electromechanical symmetry

  19. Fault strength in Marmara region inferred from the geometry of the principle stress axes and fault orientations: A case study for the Prince's Islands fault segment

    Science.gov (United States)

    Pinar, Ali; Coskun, Zeynep; Mert, Aydin; Kalafat, Dogan

    2015-04-01

    The general consensus based on historical earthquake data point out that the last major moment release on the Prince's islands fault was in 1766 which in turn signals an increased seismic risk for Istanbul Metropolitan area considering the fact that most of the 20 mm/yr GPS derived slip rate for the region is accommodated mostly by that fault segment. The orientation of the Prince's islands fault segment overlaps with the NW-SE direction of the maximum principle stress axis derived from the focal mechanism solutions of the large and moderate sized earthquakes occurred in the Marmara region. As such, the NW-SE trending fault segment translates the motion between the two E-W trending branches of the North Anatolian fault zone; one extending from the Gulf of Izmit towards Çınarcık basin and the other extending between offshore Bakırköy and Silivri. The basic relation between the orientation of the maximum and minimum principal stress axes, the shear and normal stresses, and the orientation of a fault provides clue on the strength of a fault, i.e., its frictional coefficient. Here, the angle between the fault normal and maximum compressive stress axis is a key parameter where fault normal and fault parallel maximum compressive stress might be a necessary and sufficient condition for a creeping event. That relation also implies that when the trend of the sigma-1 axis is close to the strike of the fault the shear stress acting on the fault plane approaches zero. On the other hand, the ratio between the shear and normal stresses acting on a fault plane is proportional to the coefficient of frictional coefficient of the fault. Accordingly, the geometry between the Prince's islands fault segment and a maximum principal stress axis matches a weak fault model. In the frame of the presentation we analyze seismological data acquired in Marmara region and interpret the results in conjuction with the above mentioned weak fault model.

  20. Maximum entropy production rate in quantum thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Beretta, Gian Paolo, E-mail: beretta@ing.unibs.i [Universita di Brescia, via Branze 38, 25123 Brescia (Italy)

    2010-06-01

    In the framework of the recent quest for well-behaved nonlinear extensions of the traditional Schroedinger-von Neumann unitary dynamics that could provide fundamental explanations of recent experimental evidence of loss of quantum coherence at the microscopic level, a recent paper [Gheorghiu-Svirschevski 2001 Phys. Rev. A 63 054102] reproposes the nonlinear equation of motion proposed by the present author [see Beretta G P 1987 Found. Phys. 17 365 and references therein] for quantum (thermo)dynamics of a single isolated indivisible constituent system, such as a single particle, qubit, qudit, spin or atomic system, or a Bose-Einstein or Fermi-Dirac field. As already proved, such nonlinear dynamics entails a fundamental unifying microscopic proof and extension of Onsager's reciprocity and Callen's fluctuation-dissipation relations to all nonequilibrium states, close and far from thermodynamic equilibrium. In this paper we propose a brief but self-contained review of the main results already proved, including the explicit geometrical construction of the equation of motion from the steepest-entropy-ascent ansatz and its exact mathematical and conceptual equivalence with the maximal-entropy-generation variational-principle formulation presented in Gheorghiu-Svirschevski S 2001 Phys. Rev. A 63 022105. Moreover, we show how it can be extended to the case of a composite system to obtain the general form of the equation of motion, consistent with the demanding requirements of strong separability and of compatibility with general thermodynamics principles. The irreversible term in the equation of motion describes the spontaneous attraction of the state operator in the direction of steepest entropy ascent, thus implementing the maximum entropy production principle in quantum theory. The time rate at which the path of steepest entropy ascent is followed has so far been left unspecified. As a step towards the identification of such rate, here we propose a possible

  1. Nanocrystalline dye-sensitized solar cells having maximum performance

    Energy Technology Data Exchange (ETDEWEB)

    Kroon, M.; Bakker, N.J.; Smit, H.J.P. [ECN Solar Energy, Petten (Netherlands); Liska, P.; Thampi, K.R.; Wang, P.; Zakeeruddin, S.M.; Graetzel, M. [LPI-ISIC, Ecole Polytechnique Federale de Lausanne EPFL, Station 6, CH-1015 Lausanne (Switzerland); Hinsch, A. [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr.2, D-79110 Freiburg (Germany); Hore, S.; Wuerfel, U.; Sastrawan, R. [Freiburg Materials Research Centre FMF, Stefan-Meier Str. 21, 79104 Freiburg (Germany); Durrant, J.R.; Palomares, E. [Centre for Electronic Materials and Devices, Department of Chemistry, Imperial College London, Exhibition road SW7 2AY (United Kingdom); Pettersson, H.; Gruszecki, T. [IVF Industrial Research and Development Corporation, Argongatan 30, SE-431 53 Moelndal (Sweden); Walter, J.; Skupien, K. [Cracow University of Technology CUTECH, Jana Pawla II 37, 31-864 Cracow (Poland); Tulloch, G.E. [Greatcell Solar SA GSA, Ave Henry-Warnery 4, 1006 Lausanne (Switzerland)

    2007-01-15

    This paper presents an overview of the research carried out by a European consortium with the aim to develop and test new and improved ways to realise dye-sensitized solar cells (DSC) with enhanced efficiencies and stabilities. Several new areas have been explored in the field of new concepts and materials, fabrication protocols for TiO2 and scatterlayers, metal oxide blocking layers, strategies for co-sensitization and low temperature processes of platinum deposition. Fundamental understanding of the working principles has been gained by means of electrical and optical modelling and advanced characterization techniques. Cost analyses have been made to demonstrate the potential of DSC as a low cost thin film PV technology. The combined efforts have led to maximum non-certified power conversion efficiencies under full sunlight of 11% for areas <0c2 cm{sup 2} and 10c1% for a cell with an active area of 1c3 cm{sup 2}. Lifetime studies revealed negligible device degradation after 1000 hrs of accelerated tests under thermal stress at 80C in the dark and visible light soaking at 60C. An outlook summarizing future directions in the research and large-scale production of DSC is presented.

  2. Using X-ray microbeam diffraction to study the long-range internal stresses in aluminum processed by ECAP

    International Nuclear Information System (INIS)

    Lee, I-Fang; Phan, Thien Q.; Levine, Lyle E.; Tischler, Jonathan Z.; Geantil, Peter T.; Huang, Yi; Langdon, Terence G.; Kassner, Michael E.

    2013-01-01

    Aluminum alloy 1050 was processed by equal-channel angular pressing (ECAP) using a single pass (equivalent uniaxial strain of about 0.88). Long-range internal stresses (LRISs) were assessed in the grain/subgrain interiors using X-ray microbeam diffraction to measure the spacing of {5 3 1} planes, with normals oriented approximately +27.3°, +4.9° and −17.5° off the pressing (axial) direction. The results are consistent with mechanical analysis that suggests the maximum tensile plastic-strain after one pass is expected for +22.5°, roughly zero along the pressing axis, and maximum compressive strain for the −67.5° direction. The magnitude of the measured maximum compressive long-range internal stress is about 0.13σ a (applied stress) in low-dislocation regions within the grain/subgrain interiors. This work is placed in the context of earlier work where convergent beam electron diffraction was used to analyze LRISs in close proximity to the deformation-induced boundaries. The results are complementary and the measured stresses are consistent with a composite model for long-range internal stresses

  3. Stress transfer mechanisms at the submicron level for graphene/polymer systems.

    Science.gov (United States)

    Anagnostopoulos, George; Androulidakis, Charalampos; Koukaras, Emmanuel N; Tsoukleri, Georgia; Polyzos, Ioannis; Parthenios, John; Papagelis, Konstantinos; Galiotis, Costas

    2015-02-25

    The stress transfer mechanism from a polymer substrate to a nanoinclusion, such as a graphene flake, is of extreme interest for the production of effective nanocomposites. Previous work conducted mainly at the micron scale has shown that the intrinsic mechanism of stress transfer is shear at the interface. However, since the interfacial shear takes its maximum value at the very edge of the nanoinclusion it is of extreme interest to assess the effect of edge integrity upon axial stress transfer at the submicron scale. Here, we conduct a detailed Raman line mapping near the edges of a monolayer graphene flake that is simply supported onto an epoxy-based photoresist (SU8)/poly(methyl methacrylate) matrix at steps as small as 100 nm. We show for the first time that the distribution of axial strain (stress) along the flake deviates somewhat from the classical shear-lag prediction for a region of ∼ 2 μm from the edge. This behavior is mainly attributed to the presence of residual stresses, unintentional doping, and/or edge effects (deviation from the equilibrium values of bond lengths and angles, as well as different edge chiralities). By considering a simple balance of shear-to-normal stresses at the interface we are able to directly convert the strain (stress) gradient to values of interfacial shear stress for all the applied tensile levels without assuming classical shear-lag behavior. For large flakes a maximum value of interfacial shear stress of 0.4 MPa is obtained prior to flake slipping.

  4. Magnetic memory signals variation induced by applied magnetic field and static tensile stress in ferromagnetic steel

    International Nuclear Information System (INIS)

    Huang, Haihong; Yang, Cheng; Qian, Zhengchun; Han, Gang; Liu, Zhifeng

    2016-01-01

    Stress can induce a spontaneous magnetic field in ferromagnetic steel under the excitation of geomagnetic field. In order to investigate the impact of applied magnetic field and tensile stress on variation of the residual magnetic signals on the surface of ferromagnetic materials, static tensile tests of Q235 structural steel were carried out, with the normal component of the residual magnetic signals, H p (y), induced by applied magnetic fields with different intensities measured through the tensile tests. The H p (y), its slope coefficient K S and maximum gradient K max changing with the applied magnetic field H and tensile stress were observed. Results show that the magnitude of H p (y) and its slope coefficient K S increase linearly with the increase of stress in the elastic deformation stage. Under yield stress, H p (y) and K S reach its maximum, and then decrease slightly with further increase of stress. Applied magnetic field affects the magnitude of H p (y) instead of changing the signal curve′s profile; and the magnitude of H p (y), K S , K max and the change rate of K S increase with the increase of applied magnetic field. The phenomenon is also discussed from the viewpoint of magnetic charge in ferromagnetic materials. - Highlights: • We investigated how applied magnetic field and tensile stress impact H p (y) signals. • Magnitude of H p (y), K S and K max increase with the increase of applied magnetic field. • Both applied magnetic field and tensile stress impact material magnetic permeability. • Applied magnetic field can help to evaluate the stress distribution of components.

  5. Magnetic memory signals variation induced by applied magnetic field and static tensile stress in ferromagnetic steel

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Haihong, E-mail: huanghaihong@hfut.edu.cn; Yang, Cheng; Qian, Zhengchun; Han, Gang; Liu, Zhifeng

    2016-10-15

    Stress can induce a spontaneous magnetic field in ferromagnetic steel under the excitation of geomagnetic field. In order to investigate the impact of applied magnetic field and tensile stress on variation of the residual magnetic signals on the surface of ferromagnetic materials, static tensile tests of Q235 structural steel were carried out, with the normal component of the residual magnetic signals, H{sub p}(y), induced by applied magnetic fields with different intensities measured through the tensile tests. The H{sub p}(y), its slope coefficient K{sub S} and maximum gradient K{sub max} changing with the applied magnetic field H and tensile stress were observed. Results show that the magnitude of H{sub p}(y) and its slope coefficient K{sub S} increase linearly with the increase of stress in the elastic deformation stage. Under yield stress, H{sub p}(y) and K{sub S} reach its maximum, and then decrease slightly with further increase of stress. Applied magnetic field affects the magnitude of H{sub p}(y) instead of changing the signal curve′s profile; and the magnitude of H{sub p}(y), K{sub S}, K{sub max} and the change rate of K{sub S} increase with the increase of applied magnetic field. The phenomenon is also discussed from the viewpoint of magnetic charge in ferromagnetic materials. - Highlights: • We investigated how applied magnetic field and tensile stress impact H{sub p}(y) signals. • Magnitude of H{sub p}(y), K{sub S} and K{sub max} increase with the increase of applied magnetic field. • Both applied magnetic field and tensile stress impact material magnetic permeability. • Applied magnetic field can help to evaluate the stress distribution of components.

  6. Determination of the maximum-depth to potential field sources by a maximum structural index method

    Science.gov (United States)

    Fedi, M.; Florio, G.

    2013-01-01

    A simple and fast determination of the limiting depth to the sources may represent a significant help to the data interpretation. To this end we explore the possibility of determining those source parameters shared by all the classes of models fitting the data. One approach is to determine the maximum depth-to-source compatible with the measured data, by using for example the well-known Bott-Smith rules. These rules involve only the knowledge of the field and its horizontal gradient maxima, and are independent from the density contrast. Thanks to the direct relationship between structural index and depth to sources we work out a simple and fast strategy to obtain the maximum depth by using the semi-automated methods, such as Euler deconvolution or depth-from-extreme-points method (DEXP). The proposed method consists in estimating the maximum depth as the one obtained for the highest allowable value of the structural index (Nmax). Nmax may be easily determined, since it depends only on the dimensionality of the problem (2D/3D) and on the nature of the analyzed field (e.g., gravity field or magnetic field). We tested our approach on synthetic models against the results obtained by the classical Bott-Smith formulas and the results are in fact very similar, confirming the validity of this method. However, while Bott-Smith formulas are restricted to the gravity field only, our method is applicable also to the magnetic field and to any derivative of the gravity and magnetic field. Our method yields a useful criterion to assess the source model based on the (∂f/∂x)max/fmax ratio. The usefulness of the method in real cases is demonstrated for a salt wall in the Mississippi basin, where the estimation of the maximum depth agrees with the seismic information.

  7. Effects of LSP on micro-structures and residual stresses in a 4 mm CLAM steel weld joints

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xizhang, E-mail: chenxizhang@wzu.edu.cn [School of Mechanical and Electrical Engineering, Wenzhou University., Wenzhou 325035 (China); School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China); Fang, Yuanyuan [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China); Zhang, Shuyan; Kelleher, Joe F. [ISIS, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); Zhou, Jianzhong [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu (China)

    2015-05-15

    The effects of laser shock processing (LSP) on the distribution of residual stress and micro-structure of China Low Activation Martensitic (CLAM) steel weldment were investigated via neutron diffraction and optical microscope (OM). A pair of 4 mm CLAM steel plates joined by GTA welding. Special attention is paid to the generation of high level compressive residual stresses introduced by LSP. Residual stress in longitudinal, normal and transversal direction at weldment surface and longitudinal stress through thickness are evaluated via neutron diffraction. Compressive residual stress after LSP occurred at more than 90% areas within the weld joint, it is almost double the areas of compressive stress compare to weldment surface before LSP. The maximum compressive normal residual stress becomes to −183 MPa after LSP from −63 MPa before LSP. The Modification of surface micro-structures including weld zone (WZ), heat affected zone (HAZ) and base metal (BM) are also discussed. Results to date demonstrate that laser shock processing has been a great potential method for the improvement of mechanical performance of components.

  8. Diabetes Insipidus after normal vaginal delivery: a case report

    Directory of Open Access Journals (Sweden)

    Farideh Keypour

    2014-07-01

    Treatment was continuing, when the symptoms of central diabetes insipidus resolve and urinary concentrating ability was preferred. Maximum urinary osmolality over the next 11 hours was assessed, 730 mosm/kg was considered normal. Conclusion: Close attention to electrolyte and fluid balance is important in the postpartum period. The symptoms of transient vasopressin-resistant diabetes insipidus resolve in few days to a few weeks after vaginal delivery or when hepatic function returns to normal.

  9. Weighted Maximum-Clique Transversal Sets of Graphs

    OpenAIRE

    Chuan-Min Lee

    2011-01-01

    A maximum-clique transversal set of a graph G is a subset of vertices intersecting all maximum cliques of G. The maximum-clique transversal set problem is to find a maximum-clique transversal set of G of minimum cardinality. Motivated by the placement of transmitters for cellular telephones, Chang, Kloks, and Lee introduced the concept of maximum-clique transversal sets on graphs in 2001. In this paper, we study the weighted version of the maximum-clique transversal set problem for split grap...

  10. Design and analysis of a toroidal tester for the measurement of core losses under axial compressive stress

    Energy Technology Data Exchange (ETDEWEB)

    Alatawneh, Natheer, E-mail: natheer80@yahoo.com [Department of Mining and Materials Engineering, McGill University, QC H3A 0G4 (Canada); Rahman, Tanvir; Lowther, David A. [Department of Electrical and Computer Engineering, McGill University, QC H3A 0E9 (Canada); Chromik, Richard [Department of Mining and Materials Engineering, McGill University, QC H3A 0G4 (Canada)

    2017-06-15

    Highlights: • Develop a toroidal tester for magnetic measurements under compressive axial stress. • The shape of the toroidal ring has been verified using 3D stress analysis. • The developed design has been prototyped, and measurements were carried out. • Physical explanations for the core loss trend due to stress are provided. - Abstract: Electric machine cores are subjected to mechanical stresses due to manufacturing processes. These stresses include radial, circumferential and axial components that may have significant influences on the magnetic properties of the electrical steel and hence, on the output and efficiencies of electrical machines. Previously, most studies of iron losses due to mechanical stress have considered only radial and circumferential components. In this work, an improved toroidal tester has been designed and developed to measure the core losses and the magnetic properties of electrical steel under a compressive axial stress. The shape of the toroidal ring has been verified using 3D stress analysis. Also, 3D electromagnetic simulations show a uniform flux density distribution in the specimen with a variation of 0.03 T and a maximum average induction level of 1.5 T. The developed design has been prototyped, and measurements were carried out using a steel sample of grade 35WW300. Measurements show that applying small mechanical stresses normal to the sample thickness rises the delivered core losses, then the losses decrease continuously as the stress increases. However, the drop in core losses at high stresses does not go lower than the free-stress condition. Physical explanations for the observed trend of core losses as a function of stress are provided based on core loss separation to the hysteresis and eddy current loss components. The experimental results show that the effect of axial compressive stress on magnetic properties of electrical steel at high level of inductions becomes less pronounced.

  11. On the Five-Moment Hamburger Maximum Entropy Reconstruction

    Science.gov (United States)

    Summy, D. P.; Pullin, D. I.

    2018-05-01

    We consider the Maximum Entropy Reconstruction (MER) as a solution to the five-moment truncated Hamburger moment problem in one dimension. In the case of five monomial moment constraints, the probability density function (PDF) of the MER takes the form of the exponential of a quartic polynomial. This implies a possible bimodal structure in regions of moment space. An analytical model is developed for the MER PDF applicable near a known singular line in a centered, two-component, third- and fourth-order moment (μ _3 , μ _4 ) space, consistent with the general problem of five moments. The model consists of the superposition of a perturbed, centered Gaussian PDF and a small-amplitude packet of PDF-density, called the outlying moment packet (OMP), sitting far from the mean. Asymptotic solutions are obtained which predict the shape of the perturbed Gaussian and both the amplitude and position on the real line of the OMP. The asymptotic solutions show that the presence of the OMP gives rise to an MER solution that is singular along a line in (μ _3 , μ _4 ) space emanating from, but not including, the point representing a standard normal distribution, or thermodynamic equilibrium. We use this analysis of the OMP to develop a numerical regularization of the MER, creating a procedure we call the Hybrid MER (HMER). Compared with the MER, the HMER is a significant improvement in terms of robustness and efficiency while preserving accuracy in its prediction of other important distribution features, such as higher order moments.

  12. Pattern formation, logistics, and maximum path probability

    Science.gov (United States)

    Kirkaldy, J. S.

    1985-05-01

    The concept of pattern formation, which to current researchers is a synonym for self-organization, carries the connotation of deductive logic together with the process of spontaneous inference. Defining a pattern as an equivalence relation on a set of thermodynamic objects, we establish that a large class of irreversible pattern-forming systems, evolving along idealized quasisteady paths, approaches the stable steady state as a mapping upon the formal deductive imperatives of a propositional function calculus. In the preamble the classical reversible thermodynamics of composite systems is analyzed as an externally manipulated system of space partitioning and classification based on ideal enclosures and diaphragms. The diaphragms have discrete classification capabilities which are designated in relation to conserved quantities by descriptors such as impervious, diathermal, and adiabatic. Differentiability in the continuum thermodynamic calculus is invoked as equivalent to analyticity and consistency in the underlying class or sentential calculus. The seat of inference, however, rests with the thermodynamicist. In the transition to an irreversible pattern-forming system the defined nature of the composite reservoirs remains, but a given diaphragm is replaced by a pattern-forming system which by its nature is a spontaneously evolving volume partitioner and classifier of invariants. The seat of volition or inference for the classification system is thus transferred from the experimenter or theoretician to the diaphragm, and with it the full deductive facility. The equivalence relations or partitions associated with the emerging patterns may thus be associated with theorems of the natural pattern-forming calculus. The entropy function, together with its derivatives, is the vehicle which relates the logistics of reservoirs and diaphragms to the analog logistics of the continuum. Maximum path probability or second-order differentiability of the entropy in isolation are

  13. Normal Reactions to Orthostatic Stress in Rett Syndrome

    Science.gov (United States)

    Larsson, Gunilla; Julu, Peter O. O.; Engerstrom, Ingegerd Witt; Sandlund, Marlene; Lindstrom, Britta

    2013-01-01

    The aim of this study was to investigate orthostatic reactions in females with Rett syndrome (RTT), and also whether the severity of the syndrome had an impact on autonomic reactions. Based on signs of impaired function of the central autonomic system found in RTT, it could be suspected that orthostatic reactions were affected. The orthostatic…

  14. Analysis of rock stress and rock stress measurements with application to Aespoe HRL

    International Nuclear Information System (INIS)

    Lundholm, Beatrice

    2000-11-01

    The process of choosing a site for a nuclear waste repository means that many aspects have to be taken into consideration. One of these is that the repository has to be mechanically stable for a long time. The mechanical stability of the rock is very difficult to determine. One of several factors, which determine the mechanical stability, is the virgin state of stress. The thesis project consists of two parts. In the first part the state of stress at Aespoe Hard Rock Laboratory had to be defined. This was done based on earlier rock stress measurements conducted during the years 1988 to 1997. Two different measurement techniques have been used, hydraulic fracturing and overcoring. During the overcoring two types of cells have been used, CSIRO HI-cell and a cell developed by the Swedish State Power Board (SSPB). In the second part of the project, investigation of the correlation between the stress and geological structures are made using numerical modelling tools such as FLAC, UDEC and 3DEC. The rock stress measurements using the hydraulic fracturing gave orientations of the horizontal stress that coincide with earlier hydraulic fracturing measurements conducted in Scandinavia. The magnitudes of rock stresses are slightly lower than the earlier reported stress magnitudes for the Scandinavian part of the earth crust. The rock stresses obtained from the overcoring resulted in higher stresses than what was predicted by the hydraulic fracturing measurements. However, the orientation of the maximum horizontal stresses coincides well between the two techniques. The orientation is also more or less constant with respect to increasing depth. The state of stress at Aespoe is defined by using the results from the hydraulic fracturing and the measurements conducted by SSPB-cell. The measurements from the SSPB-cell are used since these have a Poisson's ratio that corresponds well with the uniaxial tests of rock samples and since the measurements have been done at a distance from

  15. QTLs for seedling traits under salinity stress in hexaploid wheat

    Directory of Open Access Journals (Sweden)

    Yongzhe Ren

    2018-03-01

    Full Text Available ABSTRACT: Soil salinity limits agricultural production and is a major obstacle for increasing crop yield. Common wheat is one of the most important crops with allohexaploid characteristic and a highly complex genome. QTL mapping is a useful way to identify genes for quantitative traits such as salinity tolerance in hexaploid wheat. In the present study, a hydroponic trial was carried out to identify quantitative trait loci (QTLs associated with salinity tolerance of wheat under 150mM NaCl concentration using a recombinant inbred line population (Xiaoyan 54×Jing 411. Values of wheat seedling traits including maximum root length (MRL, root dry weight (RDW, shoot dry weight (SDW, total dry weight (TDW and the ratio of TDW of wheat plants between salt stress and control (TDWR were evaluated or calculated. A total of 19QTLs for five traits were detected through composite interval mapping method by using QTL Cartographer version 2.5 under normal and salt stress conditions. These QTLs distributed on 12 chromosomes explained the percentage of phenotypic variation by individual QTL varying from 7.9% to 19.0%. Among them, 11 and six QTLs were detected under normal and salt stress conditions, respectively and two QTLs were detected for TDWR. Some salt tolerance related loci may be pleiotropic. Chromosome 1A, 3A and 7A may harbor crucial candidate genes associated with wheat salt tolerance. Our results would be helpful for the marker assisted selection to breed wheat varieties with improved salt tolerance.

  16. Causality between expansion of seismic cloud and maximum magnitude of induced seismicity in geothermal field

    Science.gov (United States)

    Mukuhira, Yusuke; Asanuma, Hiroshi; Ito, Takatoshi; Häring, Markus

    2016-04-01

    Occurrence of induced seismicity with large magnitude is critical environmental issues associated with fluid injection for shale gas/oil extraction, waste water disposal, carbon capture and storage, and engineered geothermal systems (EGS). Studies for prediction of the hazardous seismicity and risk assessment of induced seismicity has been activated recently. Many of these studies are based on the seismological statistics and these models use the information of the occurrence time and event magnitude. We have originally developed physics based model named "possible seismic moment model" to evaluate seismic activity and assess seismic moment which can be ready to release. This model is totally based on microseismic information of occurrence time, hypocenter location and magnitude (seismic moment). This model assumes existence of representative parameter having physical meaning that release-able seismic moment per rock volume (seismic moment density) at given field. Seismic moment density is to be estimated from microseismic distribution and their seismic moment. In addition to this, stimulated rock volume is also inferred by progress of microseismic cloud at given time and this quantity can be interpreted as the rock volume which can release seismic energy due to weakening effect of normal stress by injected fluid. Product of these two parameters (equation (1)) provide possible seismic moment which can be released from current stimulated zone as a model output. Difference between output of this model and observed cumulative seismic moment corresponds the seismic moment which will be released in future, based on current stimulation conditions. This value can be translated into possible maximum magnitude of induced seismicity in future. As this way, possible seismic moment can be used to have feedback to hydraulic stimulation operation in real time as an index which can be interpreted easily and intuitively. Possible seismic moment is defined as equation (1), where D

  17. Accurate modeling and maximum power point detection of ...

    African Journals Online (AJOL)

    Accurate modeling and maximum power point detection of photovoltaic ... Determination of MPP enables the PV system to deliver maximum available power. ..... adaptive artificial neural network: Proposition for a new sizing procedure.

  18. Maximum power per VA control of vector controlled interior ...

    Indian Academy of Sciences (India)

    Thakur Sumeet Singh

    2018-04-11

    Apr 11, 2018 ... Department of Electrical Engineering, Indian Institute of Technology Delhi, New ... The MPVA operation allows maximum-utilization of the drive-system. ... Permanent magnet motor; unity power factor; maximum VA utilization; ...

  19. Electron density distribution in Si and Ge using multipole, maximum ...

    Indian Academy of Sciences (India)

    Si and Ge has been studied using multipole, maximum entropy method (MEM) and ... and electron density distribution using the currently available versatile ..... data should be subjected to maximum possible utility for the characterization of.

  20. PRINCIPAL STRESSES IN NON-LINEAR ANALYSIS OF BAKUN CONCRETE FACED ROCKFILL DAM

    Directory of Open Access Journals (Sweden)

    Mohd Hilton Ahmad

    2017-11-01

    Full Text Available With rapid population growth and accelerating economic development, much of the world’s WATER which requires urgent attention to ensure sustainable use. Nowadays, Concrete Faced Rockfill Dam (CFRD is preferred among dam consultant due to its advantages. They are designed to withstand all applied loads; namely gravity load due to its massive weight and hydrostatic load due to water thrust from the reservoir. Bakun CFRD, which ranks as the second highest CFRD in the world when completed, is analyzed to its safety due to both loads mentioned earlier by using Finite Element Method. 2-D plane strain finite element analysis of non-linear Duncan-Chang hyperbolic Model which formulated by Duncan and Chang is used to study the structural response of the dam in respect to the deformation and stresses of Main dam of Bakun’s CFRD project. Dead-Birth-Ghost element technique was used to simulate sequences of construction of the dam as well as during reservoir fillings. The comparison of rigid and flexible foundation on the behaviour of the dam was discussed. The maximum and minimum principal stresses are the maximum and minimum possible values of the normal stresses. The maximum principal stress controls brittle fracture. In the finite element modeling the concrete slab on the upstream was represented through six-noded element, while the interface characteristic between dam body and concrete slab was modeled using interface element. The maximum settlement and stresses of the cross section was founded and the distribution of them were discussed and tabulated in form of contours.