Tanabe, Yuki; Kido, Teruhito; Kurata, Akira; Sawada, Shun; Suekuni, Hiroshi; Kido, Tomoyuki; Yokoi, Takahiro; Miyagawa, Masao; Mochizuki, Teruhito [Ehime University Graduate School of Medicine, Department of Radiology, Toon City, Ehime (Japan); Uetani, Teruyoshi; Inoue, Katsuji [Ehime University Graduate School of Medicine, Department of Cardiology, Pulmonology, Hypertension and Nephrology, Toon City, Ehime (Japan)
2017-04-15
To evaluate the feasibility of three-dimensional (3D) maximum principal strain (MP-strain) derived from cardiac computed tomography (CT) for detecting myocardial infarction (MI). Forty-three patients who underwent cardiac CT and magnetic resonance imaging (MRI) were retrospectively selected. Using the voxel tracking of motion coherence algorithm, the peak CT MP-strain was measured using the 16-segment model. With the trans-mural extent of late gadolinium enhancement (LGE) and the distance from MI, all segments were classified into four groups (infarcted, border, adjacent, and remote segments); infarcted and border segments were defined as MI with LGE positive. Diagnostic performance of MP-strain for detecting MI was compared with per cent systolic wall thickening (%SWT) assessed by MRI using receiver-operating characteristic curve analysis at a segment level. Of 672 segments excluding16 segments influenced by artefacts, 193 were diagnosed as MI. Sensitivity and specificity of peak MP-strain to identify MI were 81 % [95 % confidence interval (95 % CI): 74-88 %] and 86 % (81-92 %) compared with %SWT: 76 % (60-95 %) and 68 % (48-84 %), respectively. The area under the curve of peak MP-strain was superior to %SWT [0.90 (0.87-0.93) vs. 0.80 (0.76-0.83), p < 0.05]. CT MP-strain has a potential to provide incremental value to coronary CT angiography for detecting MI. (orig.)
Kirkpatrick Mark
2005-01-01
Full Text Available Abstract Principal component analysis is a widely used 'dimension reduction' technique, albeit generally at a phenotypic level. It is shown that we can estimate genetic principal components directly through a simple reparameterisation of the usual linear, mixed model. This is applicable to any analysis fitting multiple, correlated genetic effects, whether effects for individual traits or sets of random regression coefficients to model trajectories. Depending on the magnitude of genetic correlation, a subset of the principal component generally suffices to capture the bulk of genetic variation. Corresponding estimates of genetic covariance matrices are more parsimonious, have reduced rank and are smoothed, with the number of parameters required to model the dispersion structure reduced from k(k + 1/2 to m(2k - m + 1/2 for k effects and m principal components. Estimation of these parameters, the largest eigenvalues and pertaining eigenvectors of the genetic covariance matrix, via restricted maximum likelihood using derivatives of the likelihood, is described. It is shown that reduced rank estimation can reduce computational requirements of multivariate analyses substantially. An application to the analysis of eight traits recorded via live ultrasound scanning of beef cattle is given.
Kernel principal component and maximum autocorrelation factor analyses for change detection
Nielsen, Allan Aasbjerg; Canty, Morton John
2009-01-01
in Nevada acquired on successive passes of the Landsat-5 satellite in August-September 1991. The six-band images (the thermal band is omitted) with 1,000 by 1,000 28.5 m pixels were first processed with the iteratively re-weighted MAD (IR-MAD) algorithm in order to discriminate change. Then the MAD image......Principal component analysis (PCA) has often been used to detect change over time in remotely sensed images. A commonly used technique consists of finding the projections along the eigenvectors for data consisting of pair-wise (perhaps generalized) differences between corresponding spectral bands...... covering the same geographical region acquired at two different time points. In this paper kernel versions of the principal component and maximum autocorrelation factor (MAF) transformations are used to carry out the analysis. An example is based on bi-temporal Landsat-5 TM imagery over irrigation fields...
Wang, G. D.; Chan, L. C.
2009-11-01
In order to find a feasible method to evaluate the deformation of tubes during the Tube Hydroforming (THF) process, the hardness and the strain in two selected deformation areas of hydro formed copper tubes (C11000) were measured and tested, and an instinct relationship was found between the hardness and the principal strains of the tubes. The major strain of the surface of tubes had the strongest linear relationship with hardness. A regression formula was used to describe the relationship between hardness and the sensitive strain which is defined in the present work as a dependent variable of major strain and thickness strain.
Gu, Fei; Wu, Hao
2016-09-01
The specifications of state space model for some principal component-related models are described, including the independent-group common principal component (CPC) model, the dependent-group CPC model, and principal component-based multivariate analysis of variance. Some derivations are provided to show the equivalence of the state space approach and the existing Wishart-likelihood approach. For each model, a numeric example is used to illustrate the state space approach. In addition, a simulation study is conducted to evaluate the standard error estimates under the normality and nonnormality conditions. In order to cope with the nonnormality conditions, the robust standard errors are also computed. Finally, other possible applications of the state space approach are discussed at the end.
Philipsen, Kirsten Riber; Christiansen, Lasse Engbo; Mandsberg, Lotte Frigaard
2008-01-01
that best describes data is a model taking into account the full covariance structure. An inference study is made in order to determine whether the growth rate of the five bacteria strains is the same. After applying a likelihood-ratio test to models with a full covariance structure, it is concluded...... that the specific growth rate is the same for all bacteria strains. This study highlights the importance of carrying out an explorative examination of residuals in order to make a correct parametrization of a model including the covariance structure. The ML method is shown to be a strong tool as it enables......The specific growth rate for P. aeruginosa and four mutator strains mutT, mutY, mutM and mutY–mutM is estimated by a suggested Maximum Likelihood, ML, method which takes the autocorrelation of the observation into account. For each bacteria strain, six wells of optical density, OD, measurements...
Curiale, Ariel H; Vegas-Sánchez-Ferrero, Gonzalo; Bosch, Johan G; Aja-Fernández, Santiago
2015-08-01
The strain and strain-rate measures are commonly used for the analysis and assessment of regional myocardial function. In echocardiography (EC), the strain analysis became possible using Tissue Doppler Imaging (TDI). Unfortunately, this modality shows an important limitation: the angle between the myocardial movement and the ultrasound beam should be small to provide reliable measures. This constraint makes it difficult to provide strain measures of the entire myocardium. Alternative non-Doppler techniques such as Speckle Tracking (ST) can provide strain measures without angle constraints. However, the spatial resolution and the noisy appearance of speckle still make the strain estimation a challenging task in EC. Several maximum likelihood approaches have been proposed to statistically characterize the behavior of speckle, which results in a better performance of speckle tracking. However, those models do not consider common transformations to achieve the final B-mode image (e.g. interpolation). This paper proposes a new maximum likelihood approach for speckle tracking which effectively characterizes speckle of the final B-mode image. Its formulation provides a diffeomorphic scheme than can be efficiently optimized with a second-order method. The novelty of the method is threefold: First, the statistical characterization of speckle generalizes conventional speckle models (Rayleigh, Nakagami and Gamma) to a more versatile model for real data. Second, the formulation includes local correlation to increase the efficiency of frame-to-frame speckle tracking. Third, a probabilistic myocardial tissue characterization is used to automatically identify more reliable myocardial motions. The accuracy and agreement assessment was evaluated on a set of 16 synthetic image sequences for three different scenarios: normal, acute ischemia and acute dyssynchrony. The proposed method was compared to six speckle tracking methods. Results revealed that the proposed method is the most
GUO Qintao; ZHANG Lingmi; TAO Zheng
2008-01-01
Thin wall component is utilized to absorb impact energy of a structure. However, the dynamic behavior of such thin-walled structure is highly non-linear with material, geometry and boundary non-linearity. A model updating and validation procedure is proposed to build accurate finite element model of a frame structure with a non-linear thin-walled component for dynamic analysis. Design of experiments (DOE) and principal component decomposition (PCD) approach are applied to extract dynamic feature from nonlinear impact response for correlation of impact test result and FE model of the non-linear structure. A strain-rate-dependent non-linear model updating method is then developed to build accurate FE model of the structure. Computer simulation and a real frame structure with a highly non-linear thin-walled component are employed to demonstrate the feasibility and effectiveness of the proposed approach.
Lee, H.; Haimson, B.
2007-12-01
Salinian granodiorite core from the 1462-1470m segment of the SAFOD drillhole was used to derive its critical mechanical properties under true triaxial stress conditions, analyze shear localization and brittle fracture characteristics, and establish the strength criterion under dry conditions (Eos Trans. AGU, 87/52, Abstract T32C- 03). Here we report on a series of true triaxial tests on 'unjacketed' specimens simulating stress conditions prevailing at the drillhole wall and responsible for borehole failure in the form of breakouts. Owing to numerous random cracks inherent in the core, only 11 rectangular prismatic specimens (19×19×38 mm3) were successfully tested, employing the University of Wisconsin polyaxial cell. The two larger principal stresses, σ1 and σ2, were transmitted through metal pistons, while σ3 was applied by confining fluid pressure. Specimen sides facing σ3 were left 'unjacketed', i.e. in direct contact with the confining fluid, to simulate the condition of drilling-mud pressure applying the principal radial stress (σ3) to the exposed borehole wall. The loading path called for first bringing σ2 and σ3 to preset levels and then increasing σ1 at a constant strain rate (5x10-6/sec) until brittle failure occurred. Invariably, failure occurred at σ1 levels that were only about half as high as those in previously tested dry samples under the same σ2 and σ3 magnitudes. Instead of a shear fracture, or fault, steeply inclined in the direction of σ3, as previously observed in the dry specimens, brittle failure took the form of a localized cluster of through-going extensile cracks parallel and adjacent to the faces subjected to σ3. Since failure occurred at σ1 values close to those at dilatancy onset in dry specimens, we infer that as soon as microcracks reopened, confining fluid rushed into those daylighting at the σ3 faces and extended them along a path of least resistance, i.e. along a plane normal to σ3. Thus brittle failure under
Satriano, Alessandro; Heydari, Bobak; Narous, Mariam; Exner, Derek V; Mikami, Yoko; Attwood, Monica M; Tyberg, John V; Lydell, Carmen P; Howarth, Andrew G; Fine, Nowell M; White, James A
2017-07-06
Two-dimensional (2D) strain analysis is constrained by geometry-dependent reference directions of deformation (i.e. radial, circumferential, and longitudinal) following the assumption of cylindrical chamber architecture. Three-dimensional (3D) principal strain analysis may overcome such limitations by referencing intrinsic (i.e. principal) directions of deformation. This study aimed to demonstrate clinical feasibility of 3D principal strain analysis from routine 2D cine MRI with validation to strain from 2D tagged cine analysis and 3D speckle tracking echocardiography. Thirty-one patients undergoing cardiac MRI were studied. 3D strain was measured from routine, multi-planar 2D cine SSFP images using custom software designed to apply 4D deformation fields to 3D cardiac models to derive principal strain. Comparisons of strain estimates versus those by 2D tagged cine, 2D non-tagged cine (feature tracking), and 3D speckle tracking echocardiography (STE) were performed. Mean age was 51 ± 14 (36% female). Mean LV ejection fraction was 66 ± 10% (range 37-80%). 3D principal strain analysis was feasible in all subjects and showed high inter- and intra-observer reproducibility (ICC range 0.83-0.97 and 0.83-0.98, respectively-p tracking) estimates of longitudinal (r = 0.85 and -0.83), circumferential (r = 0.88 and r = -0.87), and radial strain (r = -0.79 and r = 0.84, p < 0.0001 for all). 3D principal strain analysis is feasible using routine, multi-planar 2D cine MRI and shows high reproducibility with strong correlations to 2D conventional strain analysis and 3D STE-based analysis. Given its independence from geometry-related directions of deformation this technique may offer unique benefit for the detection and prognostication of myocardial disease, and warrants expanded investigation.
Im, Jooeun; Kim, Mihyun; Choi, Ki-Sun; Hwang, Tae-Kyung; Kwon, Il-Bum
2014-06-10
In this paper, new fiber Bragg grating (FBG) sensor probes are designed to intermittently detect the maximum tensile strain of composite materials, so as to evaluate the structural health status. This probe is fabricated by two thin Al films bonded to an FBG optical fiber and two supporting brackets, which are fixed on the surface of composite materials. The residual strain of the Al packaged FBG sensor probe is induced by the strain of composite materials. This residual strain can indicate the maximum strain of composite materials. Two types of sensor probes are prepared-one is an FBG with 18 μm thick Al films, and the other is an FBG with 36 μm thick Al films-to compare the thickness effect on the detection sensitivity. These sensor probes are bonded on the surfaces of carbon fiber reinforced plastics composite specimens. In order to determine the strain sensitivity between the residual strain of the FBG sensor probe and the maximum strain of the composite specimen, tensile tests are performed by universal testing machine, under the loading-unloading test condition. The strain sensitivities of the probes, which have the Al thicknesses of 18 and 36 μm, are determined as 0.13 and 0.23, respectively.
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.
A.H. Curiale (Ariel H.); G. Vegas-Sanchez-Ferrero (Gonzalo); J.G. Bosch (Hans); S. Aja-Fernández (Santiago)
2015-01-01
textabstractThe strain and strain-rate measures are commonly used for the analysis and assessment of regional myocardial function. In echocardiography (EC), the strain analysis became possible using Tissue Doppler Imaging (TDI). Unfortunately, this modality shows an important limitation: the angle
A.H. Curiale (Ariel H.); G. Vegas-Sanchez-Ferrero (Gonzalo); J.G. Bosch (Johan); S. Aja-Fernández (Santiago)
2015-01-01
textabstractThe strain and strain-rate measures are commonly used for the analysis and assessment of regional myocardial function. In echocardiography (EC), the strain analysis became possible using Tissue Doppler Imaging (TDI). Unfortunately, this modality shows an important limitation: the angle b
Attili, Antonio
2015-06-30
The alignment of vorticity and gradients of conserved and reactive scalars with the eigenvectors of the strain rate tensor (i.e., the principal strains) is investigated in a direct numerical simulation of a turbulent nonpremixed flame achieving a Taylor’s scale Reynolds number in the range 100≤Reλ≤150 (Attili et al. Comb. Flame, 161, 2014). The vorticity vector displays a pronounced tendency to align with the direction of the intermediate strain. These alignment statistics are in almost perfect agreement with those in homogeneous isotropic turbulence (Ashurst et al. Physics of Fluids 30, 1987) and differ significantly from the results obtained in other nonpremixed flames in which vorticity alignment with the most extensive strain was observed (Boratavet al. Physics of Fluids 8, 1996). The gradients of conserved and reactive scalars align with the most compressive strain. It is worth noting that conditioning on the local values of the mixture fraction, or equivalently conditioning on the distance from the flame sheet, does not affect the statistics. Our results suggest that turbulence overshadows the effects of heat release and chemical reactions. This may be due to the larger Reynolds number achieved in the present study compared to that in previous works.
Prediction of Maximum Strain in Finocyl Port Case-bonded Solid Propellants under Pressure Loading
Himanshu Shekhar
2006-07-01
Full Text Available Finite element analysis of case-bonded solid propellants in finocyl port configuration hasbeen carried out using finite element method. The parametric studies have also been conductedfor loading conditions, material properties, and geometrical configurations. The results arepresented in the form of a universal power law, which can be utilised for primary assessmentof peak strain in any finocyl port propellant configuration without using finite element software.This eliminates dependence on finite element software for structural integrity analysis of solidpropellants in finocyl port configuration under port pressurisation. The results obtained by finiteelement analysis and power law are in close agreement.
Philipsen, Kirsten Riber; Christiansen, Lasse Engbo; Mandsberg, Lotte Frigaard
2008-01-01
with an exponentially decaying function of the time between observations is suggested. A model with a full covariance structure containing OD-dependent variance and an autocorrelation structure is compared to a model with variance only and with no variance or correlation implemented. It is shown that the model...... are used for parameter estimation. The data is log-transformed such that a linear model can be applied. The transformation changes the variance structure, and hence an OD-dependent variance is implemented in the model. The autocorrelation in the data is demonstrated, and a correlation model...... that best describes data is a model taking into account the full covariance structure. An inference study is made in order to determine whether the growth rate of the five bacteria strains is the same. After applying a likelihood-ratio test to models with a full covariance structure, it is concluded...
PREDICTION OF MAXIMUM CREEP STRAIN OF HIGH PERFORMANCE STEEL FIBER REINFORCED CONCRETE
Mishina Alexandra Vasil'evna
2012-12-01
Full Text Available The strongest research potential is demonstrated by the areas of application of high performance steel fiber reinforced concrete (HPSFRC. The research of its rheological characteristics is very important for the purposes of understanding its behaviour. This article is an overview of an experimental study of UHSSFRC. The study was carried out in the form of lasting creep tests of HPSFRC prism specimen, loaded by stresses of varied intensity. The loading was performed at different ages: 7, 14, 28 and 90 days after concreting. The stress intensity was 0.3 and 0.6 Rb; it was identified on the basis of short-term crush tests of similar prism-shaped specimen, performed on the same day. As a result, values of ultimate creep strains and ultimate specific creep of HPSFRC were identified. The data was used to construct an experimental diagramme of the ultimate specific creep on the basis of the HPSFRC loading age if exposed to various stresses. The research has resulted in the identification of a theoretical relationship that may serve as the basis for the high-precision projection of the pattern of changes in the ultimate specific creep of HPSFRC, depending on the age of loading and the stress intensity.
Befus, M; Mukherjee, D V; Herzig, C T A; Lowy, F D; Larson, E
2017-07-01
Prisons/jails are thought to amplify the transmission of Staphylococcus aureus (SA) particularly methicillin-resistant SA infection and colonisation. Two independently pooled cross-sectional samples of detainees being admitted or discharged from two New York State maximum-security prisons were used to explore this concept. Private interviews of participants were conducted, during which the anterior nares and oropharynx were sampled and assessed for SA colonisation. Log-binomial regression and correspondence analysis (CA) were used to evaluate the prevalence of colonisation at entry as compared with discharge. Approximately 51% of admitted (N = 404) and 41% of discharged (N = 439) female detainees were colonised with SA. Among males, 59% of those admitted (N = 427) and 49% of those discharged (N = 393) were colonised. Females had a statistically significant higher prevalence (1·26: P = 0·003) whereas males showed no significant difference (1·06; P = 0·003) in SA prevalence between entry and discharge. CA demonstrated that some strains, such as spa types t571 and t002, might have an affinity for certain mucosal sites. Contrary to our hypothesis, the prison setting did not amplify SA transmission, and CA proved to be a useful tool in describing the population structure of strains according to time and/or mucosal site.
Jakobsen, Anita N; Aasen, Inga M; Strøm, Arne R
2007-09-01
We report that endogenously synthesized (-)-proto-quercitol (1D-1,3,4/2,5-cyclohexanepentol) and glycine betaine were the principal compatible solutes of Schizochytrium sp. strain S8 (ATCC 20889) and three new osmotolerant isolates of thraustochytrids (strains T65, T66, and T67). The compatible solutes were identified and quantified by use of nuclear magnetic resonance spectroscopy, and their identity was confirmed by mass spectroscopy and measurement of the specific optical rotation. The cellular content of compatible solutes increased with increasing NaCl concentration of a defined medium. (-)-proto-Quercitol was the dominating solute at all NaCl concentrations tested (0.25 to 1.0 M), e.g., cells of S8 and T66 stressed with 1.0 M NaCl accumulated about 500 micromol (-)-proto-quercitol and 100 micromol glycine betaine per g dry weight. To our knowledge, (-)-proto-quercitol has previously been found only in eucalyptus. The 18S rRNA gene sequences of the four (-)-proto-quercitol-producing strains showed 99% identity, and they displayed the same fatty acid profile. The only polyunsaturated fatty acids accumulated were docosahexaenoic acid (78%) and docosapentaenoic acid (22%). A less osmotolerant isolate (strain T29), which was closely phylogenetically related to Thraustochytrium aureum (ATCC 34304), did not contain (-)-proto-quercitol or glycine betaine. Thus, the level of osmotolerance and the osmolyte systems vary among thraustochytrids.
Sung Woo Park; Byung Kwan Oh; Hyo Seon Park
2015-01-01
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...
Solieri, Lisa; Bianchi, Aldo; Mottolese, Giovanni; Lemmetti, Federico; Giudici, Paolo
2014-04-01
Non-starter lactic acid bacteria (NSLAB) inhabiting fermented food have been recently revised as source of probiotic strains. Here, we in vitro assessed the potential probiotic aptitude of a de-replicated set of NSLAB previously isolated from long ripened Parmigiano Reggiano cheeses (22 Lactobacillus rhamnosus, 18 Lactobacillus paracasei, 3 Lactobacillus casei, 2 Lactobacillus harbinensis, and 2 Lactobacillus fermentum). Most strains showed moderate to good resistance to biological barriers, including bile salts, lysozyme, and simulated gastric and pancreatic juices. Antimicrobial susceptibility tests against seven antimicrobials belonging to different categories showed that most strains are susceptible towards all the antibiotics, with the exception of vancomycin and streptomycin. The strains lost the streptomycin resistance when assayed on agar medium containing 0.5% bile salts, suggesting that detergent-like properties of cholic acids increase membrane permeability and mediate streptomycin susceptibility. No isolate showed bile salt hydrolase (BSH) activities, supporting that bile salts resistance and BSH activity are unpaired traits. Finally, NSLAB strains had moderate to high auto-aggregative and hydrophobic phenotypes, whereas two subsets of 22 and 8 strains co-aggregated with Escherichia coli and Salmonella enterica s. typhimurium, respectively. A multivariate analysis was effective to segregate one L. casei and two L. rhamnosus strains showing physiological characteristics compatible with probiotic properties.
Strain mapping near a triple junction in strained Ni-based alloy using EBSD and biaxial nanogauges
Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Lacroute, Y.; Markey, L.; Salazar, M.; Vignal, V. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Finot, E., E-mail: Eric.Finot@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France)
2011-05-15
Research highlights: > Surface strains measured using nanogauge were compared to the texture obtained by EBSD. > Statistics of the principal strain discern the grains according to the Schmid factor. > Strain hotspots were localized near a triple junction of alloy 600 under tensile loading. > Asymetrical profile of the GB strains is a criterion for surface cracking initiation. - Abstract: A key element for analyzing the crack initiation in strained polycrystalline alloys is the local quantification of the surface strain distribution according to the grain texture. Using electron backscattered diffraction, the local microstructure was determined to both localize a triple junction and deduce the local Schmid factors. Kernel average misorientation (KAM) was also used to map the areas of defect concentration. The maximum principal strain and the in-plane shear strain were quantified using the biaxial nanogauge. Distortions of the array of nanodots used as spot markers were analyzed near the triple junction. The crystallographic orientation and the surface strain were then investigated both statistically for each grain and locally at the grain boundaries. The superimposition of microstructure and strain maps allows the high strain gradient (reaching 3-fold the applied strain) to be localized at preferential grain boundaries near the triple junction. The Schmid factors and the KAM were compared to the maximum principal strain and the in-plane shear strain respectively. The polycrystalline deformation was attributable first to the rotation of some grains, followed by the elongation of all grains along their preferential activated slip systems.
Ho, Kai-Yu; Keyak, Joyce H; Powers, Christopher M
2014-01-03
Elevated bone principal strain (an indicator of potential bone injury) resulting from reduced cartilage thickness has been suggested to contribute to patellofemoral symptoms. However, research linking patella bone strain, articular cartilage thickness, and patellofemoral pain (PFP) remains limited. The primary purpose was to determine whether females with PFP exhibit elevated patella bone strain when compared to pain-free controls. A secondary objective was to determine the influence of patella cartilage thickness on patella bone strain. Ten females with PFP and 10 gender, age, and activity-matched pain-free controls participated. Patella bone strain fields were quantified utilizing subject-specific finite element (FE) models of the patellofemoral joint (PFJ). Input parameters for the FE model included (1) PFJ geometry, (2) elastic moduli of the patella bone, (3) weight-bearing PFJ kinematics, and (4) quadriceps muscle forces. Using quasi-static simulations, peak and average minimum principal strains as well as peak and average maximum principal strains were quantified. Cartilage thickness was quantified by computing the perpendicular distance between opposing voxels defining the cartilage edges on axial plane magnetic resonance images. Compared to the pain-free controls, individuals with PFP exhibited increased peak and average minimum and maximum principal strain magnitudes in the patella. Additionally, patella cartilage thickness was negatively associated with peak minimum principal patella strain and peak maximum principal patella strain. The elevated bone strain magnitudes resulting from reduced cartilage thickness may contribute to patellofemoral symptoms and bone injury in persons with PFP. © 2013 Published by Elsevier Ltd.
Carlos Augusto de Miranda Gomide
2002-11-01
Full Text Available Buscando-se avaliar morfofisiologicamente a rebrota do capim-mombaça, quatro desfolhas foram impostas ao perfilho principal, sendo estudado o comportamento da planta em termos da taxa de expansão da área foliar, crescimento do sistema radicular, nível de carboidratos totais não estruturais (CTNE da raiz e do colmo, taxa de crescimento relativo (TCR, taxa de assimilação líquida (TAL e razão de área foliar (RAF às idades de 2, 5, 9 e 16 dias após as desfolhas, bem como da taxa fotossintética máxima às idades de 2, 6 e 13 dias das folhas remanescentes à desfolha. As desfolhas foram as seguintes: remoção de todas as lâminas foliares (desfolha total, a remoção da lâmina da folha adulta mais jovem (desfolha superior, a remoção das lâminas das duas folhas adultas mais velhas (desfolha inferior e controle (sem desfolha, juntamente com o corte dos demais perfilhos, realizado a 8 cm do solo. Foram observadas cinco repetições por tratamento, segundo o delineamento inteiramente casualizado. As folhas adultas não diferiram quanto às taxas fotossintéticas máximas, que exibiram aumento nos primeiros dias após a desfolha, e queda aos 13 dias. A desfolha reduziu os teores de CTNE da base do colmo, principalmente nas plantas sob desfolha total. Comprometimento do crescimento do sistema radicular e do teor de CTNE das raízes foi observado nas plantas sob desfolha total, que também tiveram sua TCR reduzida nos primeiros dias de rebrotação. Entretanto, o aumento na RAF possibilitou a estas plantas recuperação da TCR e alta taxa de expansão da área foliar, igualando a área foliar das demais plantas aos 16 dias de rebrota.An experiment was carried out to evaluate morphophysiological aspects of Mombaçagrass growth after defoliation. Defoliation treatments were performed when the number of green completely expanded leaves on main tiller had stabilized around 3. Four defoliation treatments were imposed to the main tiller: T1 - no
Kinkhabwala, Ali
2013-01-01
The most fundamental problem in statistics is the inference of an unknown probability distribution from a finite number of samples. For a specific observed data set, answers to the following questions would be desirable: (1) Estimation: Which candidate distribution provides the best fit to the observed data?, (2) Goodness-of-fit: How concordant is this distribution with the observed data?, and (3) Uncertainty: How concordant are other candidate distributions with the observed data? A simple unified approach for univariate data that addresses these traditionally distinct statistical notions is presented called "maximum fidelity". Maximum fidelity is a strict frequentist approach that is fundamentally based on model concordance with the observed data. The fidelity statistic is a general information measure based on the coordinate-independent cumulative distribution and critical yet previously neglected symmetry considerations. An approximation for the null distribution of the fidelity allows its direct conversi...
Wang, Haiyong; Yang, Liu; Wu, Kuo; Li, Guanghui
2014-01-16
Transcriptional engineering has presented a strong ability of phenotypic improvement in microorganisms. However, it could not be directly applied to Actinoplanes teichomyceticus L-27 because of the paucity of endogenous transcription factors in the strain. In this study, exogenous transcription factors were rationally selected and transcriptional engineering was carried out to increase the productivity of teicoplanin in L-27. It was illuminated that the σ(HrdB) molecules shared strong similarity of amino acid sequences among some genera of actinomycetes. Combining this advantage with the ability of transcriptional engineering, exogenous sigma factor σ(HrdB) molecules were rationally selected and engineered to improve L-27. hrdB genes from Actinoplanes missouriensis 431, Micromonospora aurantiaca ATCC 27029 and Salinispora arenicola CNS-205 were selected based on molecular evolutionary analysis. Random mutagenesis, DNA shuffling and point mutation were subsequently performed to generate diversified mutants. A recombinant was identified through screening program, yielding 5.3 mg/ml of teicoplanin, over 2-fold compared to that of L-27. More significantly, the engineered strain presented a good performance in 500-l pilot scale fermentation, which meant its valuable potential application in industry. Through rational selection and engineering of exogenous transcriptional factor, we have extended the application of transcriptional engineering. To our knowledge, it is the first time to focus on the related issue. In addition, possessing the advantage of efficient metabolic perturbation in transcription level, this strategy could be useful in analyzing metabolic and physiological mechanisms of strains, especially those with the only information on taxonomy.
Tsapin, A. I.; Vandenberghe, I.; Nealson, K. H.; Scott, J. H.; Meyer, T. E.; Cusanovich, M. A.; Harada, E.; Kaizu, T.; Akutsu, H.; Leys, D.;
2001-01-01
Two abundant, low-redox-potential cytochromes c were purified from the facultative anaerobe Shewanella oneidensis strain MR1 grown anaerobically with fumarate. The small cytochrome was completely sequenced, and the genes coding for both proteins were cloned and sequenced. The small cytochrome c contains 91 residues and four heme binding sites. It is most similar to the cytochromes c from Shewanella frigidimarina (formerly Shewanella putrefaciens) NCIMB400 and the unclassified bacterial strain H1R (64 and 55% identity, respectively). The amount of the small tetraheme cytochrome is regulated by anaerobiosis, but not by fumarate. The larger of the two low-potential cytochromes contains tetraheme and flavin domains and is regulated by anaerobiosis and by fumarate and thus most nearly corresponds to the flavocytochrome c-fumarate reductase previously characterized from S. frigidimarina to which it is 59% identical. However, the genetic context of the cytochrome genes is not the same for the two Shewanella species, and they are not located in multicistronic operons. The small cytochrome c and the cytochrome domain of the flavocytochrome c are also homologous, showing 34% identity. Structural comparison shows that the Shewanella tetraheme cytochromes are not related to the Desulfovibrio cytochromes c(3) but define a new folding motif for small multiheme cytochromes c.
Fotossíntese, reservas orgânicas e rebrota do capim-mombaça (Panicum maximum Jacq.sob diferentes intensidades de desfolha do perfilho principal
Gomide Carlos Augusto de Miranda
2002-01-01
Full Text Available Buscando-se avaliar morfofisiologicamente a rebrota do capim-mombaça, quatro desfolhas foram impostas ao perfilho principal, sendo estudado o comportamento da planta em termos da taxa de expansão da área foliar, crescimento do sistema radicular, nível de carboidratos totais não estruturais (CTNE da raiz e do colmo, taxa de crescimento relativo (TCR, taxa de assimilação líquida (TAL e razão de área foliar (RAF às idades de 2, 5, 9 e 16 dias após as desfolhas, bem como da taxa fotossintética máxima às idades de 2, 6 e 13 dias das folhas remanescentes à desfolha. As desfolhas foram as seguintes: remoção de todas as lâminas foliares (desfolha total, a remoção da lâmina da folha adulta mais jovem (desfolha superior, a remoção das lâminas das duas folhas adultas mais velhas (desfolha inferior e controle (sem desfolha, juntamente com o corte dos demais perfilhos, realizado a 8 cm do solo. Foram observadas cinco repetições por tratamento, segundo o delineamento inteiramente casualizado. As folhas adultas não diferiram quanto às taxas fotossintéticas máximas, que exibiram aumento nos primeiros dias após a desfolha, e queda aos 13 dias. A desfolha reduziu os teores de CTNE da base do colmo, principalmente nas plantas sob desfolha total. Comprometimento do crescimento do sistema radicular e do teor de CTNE das raízes foi observado nas plantas sob desfolha total, que também tiveram sua TCR reduzida nos primeiros dias de rebrotação. Entretanto, o aumento na RAF possibilitou a estas plantas recuperação da TCR e alta taxa de expansão da área foliar, igualando a área foliar das demais plantas aos 16 dias de rebrota.
Kiatgamolchai, S
2000-01-01
gamma has the bowl shape with the minimum at x approx 0.25-0.3. These characteristics suggest a possible influence of alloy disorder scattering. The mobilities and activation energies of the carriers in the boron-doped cap vary between samples and this is believed to be due to boron-spike near the Si/Si-substrate interface, in some samples. The source of electron-like carrier is presently unknown. Magnetotransport properties of modulation-doped p-type Si sub 1 sub - sub x Ge sub x /Si and Si sub 1 sub - sub x Ge sub x /Si sub 1 sub - sub y Ge sub y heterostructures were studied, in the magnetic field range 0-12 T, and in the temperature range 0.35-300 K. The experimental data within the classical regime have been analysed by mobility spectrum analysis, in order to separate the influences of different parallel conduction paths. A new method of mobility spectrum analysis has been developed by the based on the concept of maximum-entropy, and this computation has been shown to overcome several drawbacks or limita...
Radim Uhlář
2009-09-01
Full Text Available BACKGROUND: There are several factors (the initial ski jumper's body position and its changes at the transition to the flight phase, the magnitude and the direction of the velocity vector of the jumper's center of mass, the magnitude of the aerodynamic drag and lift forces, etc., which determine the trajectory of the jumper ski system along with the total distance of the jump. OBJECTIVE: The objective of this paper is to bring out a method based on Pontryagin's maximum principle, which allows us to obtain a solution of the optimization problem for flight style control with three constrained control variables – the angle of attack (a, body ski angle (b, and ski opening angle (V. METHODS: The flight distance was used as the optimality criterion. The borrowed regression function was taken as the source of information about the dependence of the drag (D and lift (L area on control variables with tabulated regression coefficients. The trajectories of the reference and optimized jumps were compared with the K = 125 m jumping hill profile in Frenštát pod Radhoštěm (Czech Republic and the appropriate lengths of the jumps, aerodynamic drag and lift forces, magnitudes of the ski jumper system's center of mass velocity vector and it's vertical and horizontal components were evaluated. Admissible control variables were taken at each time from the bounded set to respect the realistic posture of the ski jumper system in flight. RESULTS: It was found that a ski jumper should, within the bounded set of admissible control variables, minimize the angles (a and (b, whereas angle (V should be maximized. The length increment due to optimization is 17%. CONCLUSIONS: For future work it is necessary to determine the dependence of the aerodynamic forces acting on the ski jumper system on the flight via regression analysis of the experimental data as well as the application of the control variables related to the ski jumper's mental and motor abilities. [V
Capacitive Extensometer Particularly Suited for Measuring in Vivo Bone Strain
Perusek, Gail P. (Inventor)
2000-01-01
The present invention provides for in vivo measurements of the principal strain magnitudes and directions, and maximum shear strain that occurs in a material, such as human bone, when it is loaded (or subjected to a load). In one embodiment the invention includes a capacitive delta extensometer arranged with six sensors in a three piece configuration, with each sensor of each pair spaced apart from each other by 120 degrees.
Bro, R.; Smilde, A.K.
2014-01-01
Principal component analysis is one of the most important and powerful methods in chemometrics as well as in a wealth of other areas. This paper provides a description of how to understand, use, and interpret principal component analysis. The paper focuses on the use of principal component analysis
Elementary School Principal Effectiveness.
Cross, Ray
A review of research linking elementary principal "antecedents" (defined as traits), behaviors, school conditions, and student outcomes furnishes few supportable generalizations. The studies relating principal antecedents with behavior and principal antecedents with organizational variables reveals that the trait theory of leadership has…
Principal Ports and Facilities
California Department of Resources — The Principal Port file contains USACE port codes, geographic locations (longitude, latitude), names, and commodity tonnage summaries (total tons, domestic, foreign,...
Murphy, Lee Ann
2006-01-01
Some principals have personalities that can drive teachers around the bend and back again. Sure, most are wonderful bosses who support teachers in any way, but woe betide teachers if they are unlucky enough to run across one of the six dreaded "problem principals" identified in this article. Teachers do not have to be held hostage by difficult…
Principal Preparation Programs
Butler, Kevin
2008-01-01
A school principal's job has never been tougher. The accountability movement--culminating with the federal No Child Left Behind law in 2001--has put pressure on principals to improve student performance, resulting in school leaders' transitioning from a more administrative role to becoming more heavily involved in assessment, instruction,…
Principal noncommutative torus bundles
Echterhoff, Siegfried; Nest, Ryszard; Oyono-Oyono, Herve
2008-01-01
In this paper we study continuous bundles of C*-algebras which are non-commutative analogues of principal torus bundles. We show that all such bundles, although in general being very far away from being locally trivial bundles, are at least locally trivial with respect to a suitable bundle version...... of bivariant K-theory (denoted RKK-theory) due to Kasparov. Using earlier results of Echterhoff and Williams, we shall give a complete classification of principal non-commutative torus bundles up to equivariant Morita equivalence. We then study these bundles as topological fibrations (forgetting the group...... action) and give necessary and sufficient conditions for any non-commutative principal torus bundle being RKK-equivalent to a commutative one. As an application of our methods we shall also give a K-theoretic characterization of those principal torus-bundles with H-flux, as studied by Mathai...
Maximum Autocorrelation Factorial Kriging
Nielsen, Allan Aasbjerg; Conradsen, Knut; Pedersen, John L.
2000-01-01
This paper describes maximum autocorrelation factor (MAF) analysis, maximum autocorrelation factorial kriging, and its application to irregularly sampled stream sediment geochemical data from South Greenland. Kriged MAF images are compared with kriged images of varimax rotated factors from...
Hollar, Charlie
2004-01-01
They may never grace the pages of The Wall Street Journal or Fortune magazine, but they might possibly be the most important CEOs in our country. They are elementary school principals. Each of them typically serves the learning needs of 350-400 clients (students) while overseeing a multimillion-dollar facility staffed by 20-25 teachers and 10-15…
Strategic Principal Communication
Henry, Jake; Woody, Aaron
2013-01-01
As communities become increasingly diverse and criticism of traditional public schools intensifies, some states, such as North Carolina, have enacted legislation that encourages alternative forms of schooling. This condition has resulted in new challenges for principals to communicate broadly and often with stakeholders in an effort to build…
Stable Principal Component Pursuit
Zhou, Zihan; Wright, John; Candes, Emmanuel; Ma, Yi
2010-01-01
In this paper, we study the problem of recovering a low-rank matrix (the principal components) from a high-dimensional data matrix despite both small entry-wise noise and gross sparse errors. Recently, it has been shown that a convex program, named Principal Component Pursuit (PCP), can recover the low-rank matrix when the data matrix is corrupted by gross sparse errors. We further prove that the solution to a related convex program (a relaxed PCP) gives an estimate of the low-rank matrix that is simultaneously stable to small entrywise noise and robust to gross sparse errors. More precisely, our result shows that the proposed convex program recovers the low-rank matrix even though a positive fraction of its entries are arbitrarily corrupted, with an error bound proportional to the noise level. We present simulation results to support our result and demonstrate that the new convex program accurately recovers the principal components (the low-rank matrix) under quite broad conditions. To our knowledge, this is...
Robust Principal Component Analysis?
Candes, Emmanuel J; Ma, Yi; Wright, John
2009-01-01
This paper is about a curious phenomenon. Suppose we have a data matrix, which is the superposition of a low-rank component and a sparse component. Can we recover each component individually? We prove that under some suitable assumptions, it is possible to recover both the low-rank and the sparse components exactly by solving a very convenient convex program called Principal Component Pursuit; among all feasible decompositions, simply minimize a weighted combination of the nuclear norm and of the L1 norm. This suggests the possibility of a principled approach to robust principal component analysis since our methodology and results assert that one can recover the principal components of a data matrix even though a positive fraction of its entries are arbitrarily corrupted. This extends to the situation where a fraction of the entries are missing as well. We discuss an algorithm for solving this optimization problem, and present applications in the area of video surveillance, where our methodology allows for th...
Transforming Principal Preparation. ERIC Digest.
Lashway, Larry
In the current climate of accountability, the responsibilities of principals have increased. The new role of principals requires new forms of training, and standards-based reform is generating major changes in principal-preparation programs. This digest examines some of those changes. First, it looks at the effectiveness of principal-preparation…
Maximum Autocorrelation Factorial Kriging
Nielsen, Allan Aasbjerg; Conradsen, Knut; Pedersen, John L.; Steenfelt, Agnete
2000-01-01
This paper describes maximum autocorrelation factor (MAF) analysis, maximum autocorrelation factorial kriging, and its application to irregularly sampled stream sediment geochemical data from South Greenland. Kriged MAF images are compared with kriged images of varimax rotated factors from an ordinary non-spatial factor analysis, and they are interpreted in a geological context. It is demonstrated that MAF analysis contrary to ordinary non-spatial factor analysis gives an objective discrimina...
Recursive principal components analysis.
Voegtlin, Thomas
2005-10-01
A recurrent linear network can be trained with Oja's constrained Hebbian learning rule. As a result, the network learns to represent the temporal context associated to its input sequence. The operation performed by the network is a generalization of Principal Components Analysis (PCA) to time-series, called Recursive PCA. The representations learned by the network are adapted to the temporal statistics of the input. Moreover, sequences stored in the network may be retrieved explicitly, in the reverse order of presentation, thus providing a straight-forward neural implementation of a logical stack.
Principal Contradictions and Changes
Wang Zaibang
2006-01-01
@@ The September 11 terrorist attacks are the most notable events that occurred since the end of the Cold War. It is not only a logical outcome of world development post Cold War but is also an important variable influencing world development. In order to evaluate the influence of the development of the international relations in these five years, the international background after the Cold War must be taken into consideration and the characteristics and changes of the three principal contradictions described below need to be understood.
Maximum-biomass prediction of homofermentative Lactobacillus.
Cui, Shumao; Zhao, Jianxin; Liu, Xiaoming; Chen, Yong Q; Zhang, Hao; Chen, Wei
2016-07-01
Fed-batch and pH-controlled cultures have been widely used for industrial production of probiotics. The aim of this study was to systematically investigate the relationship between the maximum biomass of different homofermentative Lactobacillus and lactate accumulation, and to develop a prediction equation for the maximum biomass concentration in such cultures. The accumulation of the end products and the depletion of nutrients by various strains were evaluated. In addition, the minimum inhibitory concentrations (MICs) of acid anions for various strains at pH 7.0 were examined. The lactate concentration at the point of complete inhibition was not significantly different from the MIC of lactate for all of the strains, although the inhibition mechanism of lactate and acetate on Lactobacillus rhamnosus was different from the other strains which were inhibited by the osmotic pressure caused by acid anions at pH 7.0. When the lactate concentration accumulated to the MIC, the strains stopped growing. The maximum biomass was closely related to the biomass yield per unit of lactate produced (YX/P) and the MIC (C) of lactate for different homofermentative Lactobacillus. Based on the experimental data obtained using different homofermentative Lactobacillus, a prediction equation was established as follows: Xmax - X0 = (0.59 ± 0.02)·YX/P·C.
[The evolution of principal drugs in prescription compatibility].
Yuan, Bing; Shi, Dong-ping
2009-01-01
The principal drugs of principal, adjuvant, auxiliary and conductant compatiblity in prescriptions recorded in the ancient literatures had different meaning and quantities. According to the current literatures, Zhuangzi Xu Wugui took the one can cure diseases as the principal drug; The principal, adjuvant, auxiliary and conductant drugs in Shennong Bencao Jing (Shennong's Classic of Materia Medica) can be used to differentiate the good and bad of drugs; Yaoxing Lun (Treatise on medicinal property) of Zheng quan (Tang dynasty) stipulated some drugs as principal drugs; Zazhu Bencao of Jiang Xiaowan (Tang dynasty) took the one can cure yin diseases as the principal drugs; Yixue Qiyuan (the origination of medicine) of Zhang Yuansu (Jin dynasty) took the one of maximum dosage as principal drugs; Piwei Lun (Treatise on Spleen and Stomach) of LI gao (Jin dynasty) took the powerful one as the principal drug; The principal drugs in Yi Lun (medicine treatise) of Wang Kentang (Ming dynasty) changed according to different ages. The quantities of principal drugs can had two and three ingredients even took one prescription as principal drug instead of one ingredient.
Maximum likely scale estimation
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 ...
The Skills of Exemplary Principals.
Walker, John E.
1990-01-01
NASSP's Assessment Center Project has identified 12 key skills for successful principals: problem analysis, judgment, organizational ability, decisiveness, leadership, sensitivity, stress tolerance, oral communication, written communication, wide-ranging interests, personal motivation, and educational values. Effective principals succeed by…
The strong maximum principle revisited
Pucci, Patrizia; Serrin, James
In this paper we first present the classical maximum principle due to E. Hopf, together with an extended commentary and discussion of Hopf's paper. We emphasize the comparison technique invented by Hopf to prove this principle, which has since become a main mathematical tool for the study of second order elliptic partial differential equations and has generated an enormous number of important applications. While Hopf's principle is generally understood to apply to linear equations, it is in fact also crucial in nonlinear theories, such as those under consideration here. In particular, we shall treat and discuss recent generalizations of the strong maximum principle, and also the compact support principle, for the case of singular quasilinear elliptic differential inequalities, under generally weak assumptions on the quasilinear operators and the nonlinearities involved. Our principal interest is in necessary and sufficient conditions for the validity of both principles; in exposing and simplifying earlier proofs of corresponding results; and in extending the conclusions to wider classes of singular operators than previously considered. The results have unexpected ramifications for other problems, as will develop from the exposition, e.g. two point boundary value problems for singular quasilinear ordinary differential equations (Sections 3 and 4); the exterior Dirichlet boundary value problem (Section 5); the existence of dead cores and compact support solutions, i.e. dead cores at infinity (Section 7); Euler-Lagrange inequalities on a Riemannian manifold (Section 9); comparison and uniqueness theorems for solutions of singular quasilinear differential inequalities (Section 10). The case of p-regular elliptic inequalities is briefly considered in Section 11.
Maximum information photoelectron metrology
Hockett, P; Wollenhaupt, M; Baumert, T
2015-01-01
Photoelectron interferograms, manifested in photoelectron angular distributions (PADs), are a high-information, coherent observable. In order to obtain the maximum information from angle-resolved photoionization experiments it is desirable to record the full, 3D, photoelectron momentum distribution. Here we apply tomographic reconstruction techniques to obtain such 3D distributions from multiphoton ionization of potassium atoms, and fully analyse the energy and angular content of the 3D data. The PADs obtained as a function of energy indicate good agreement with previous 2D data and detailed analysis [Hockett et. al., Phys. Rev. Lett. 112, 223001 (2014)] over the main spectral features, but also indicate unexpected symmetry-breaking in certain regions of momentum space, thus revealing additional continuum interferences which cannot otherwise be observed. These observations reflect the presence of additional ionization pathways and, most generally, illustrate the power of maximum information measurements of th...
Deformation quantization of principal bundles
Aschieri, Paolo
2016-01-01
We outline how Drinfeld twist deformation techniques can be applied to the deformation quantization of principal bundles into noncommutative principal bundles, and more in general to the deformation of Hopf-Galois extensions. First we twist deform the structure group in a quantum group, and this leads to a deformation of the fibers of the principal bundle. Next we twist deform a subgroup of the group of authomorphisms of the principal bundle, and this leads to a noncommutative base space. Considering both deformations we obtain noncommutative principal bundles with noncommutative fiber and base space as well.
Ferrari, Jérôme
2015-01-01
Fasciné par la figure du physicien allemand Werner Heisenberg (1901-1976), fondateur de la mécanique quantique, inventeur du célèbre "principe d'incertitude" et Prix Nobel de physique en 1932, un jeune aspirant-philosophe désenchanté s'efforce, à l'aube du XXIe siècle, de considérer l'incomplétude de sa propre existence à l'aune des travaux et de la destinée de cet exceptionnel homme de sciences qui incarne pour lui la rencontre du langage scientifique et de la poésie, lesquels, chacun à leur manière, en ouvrant la voie au scandale de l'inédit, dessillent les yeux sur le monde pour en révéler la mystérieuse beauté que ne cessent de confisquer le matérialisme à l'œuvre dans l'Histoire des hommes.
Problems That Principals Face In School Administration
Engin Aslanargun
2012-12-01
Full Text Available Transformation is the key concept in this century that should be taken into consideration in organization anyway. Educational organizations are also under the influence of such transformation as in the case for others, the role of administrators have taken more significance that leads them to apply emerging approaches in organizational life. The purpose of this study is to define the communicative problems that principals experience in school settings and possible problem solving behaviors towards teachers. 7 principals administering schools in the town of Akçakoca, in Düzce, included the study with qualitative case design and purposive, maximum sampling procedure. It was appeared that principals have displayed in some cases similar and different administrative behaviors while tackling with communicative and problem solving conditions. It was revealed that principals tend to do their jobs within limited scope and structure based administrative style instead of consideration as a result of this study. School climate that is essential for effective learning and teaching process have been asserted to be ignored or taken less significance behind the structural and material matters
Current horizontal strain field in Chinese mainland derived from GPS data
杨国华; 李延兴; 韩月萍; 胡新康; 巩曰沐
2002-01-01
The current crustal horizontal strain field is given in the paper based on the horizontal movement rates obtained from about 400 GPS stations located in Chinese mainland and its surrounding areas. The results show: a) The horizontal strain in Chinese mainland is "strong in the west and weak in the east" and the shear strain is larger than the normal strain (absolute magnitude). The general strain magnitude is 10-8/a and in local regions is 10-7/a, but the strain distribution is not homogeneous; b) The regions with the most significant NS-trending strains are the Himalayas belt along the western segment of Chinese southern boundary, the segment of 36°N～42°N along the western boundary and the northern margin of Qaidam block; c) The EW-trending strain variation along the western margin is the maximum and it is characterized by the alternatively positive and negative variations from the west to the east; d) The regions with larger magnitudes of REN (NE-trending shear strain) and Rmax (maximum shear strain) are Himalayas belt, the segment of 36°N～42°N along the western boundary, the western part of Qaidam block, Sichuan-Yunnan (Chuan-Dian) rhombic block and the border area of Alxa, Qilian and Tarim blocks; e) The surrounding area of Qinghai-Xizang (Qingzang) block is mainly superfacial contraction and its interior is basically superfacial expansion. The area to its north is mainly superfacial contraction with the maximum magnitude along the western boundary and the minimum magnitude in the eastern part (except Yanshan tectonic zone); f) In the west of the western part, the principal compressive strain is in the SN direction and the principal tensile strain is in the EW direction, while in the eastern margin area of the western part, the principal compressive strain is proximate EW and the principal tensile strain is about SN. The principal strain direction of Chuan-Dian rhombic block has changed greatly. In the northern part, it is compression in the EW and
Maximum Likelihood Associative Memories
Gripon, Vincent; Rabbat, Michael
2013-01-01
Associative memories are structures that store data in such a way that it can later be retrieved given only a part of its content -- a sort-of error/erasure-resilience property. They are used in applications ranging from caches and memory management in CPUs to database engines. In this work we study associative memories built on the maximum likelihood principle. We derive minimum residual error rates when the data stored comes from a uniform binary source. Second, we determine the minimum amo...
Maximum likely scale estimation
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 having different derivative orders. Although the principle is applicable to a wide variety of image models, the main focus here is on the Brownian model and its use for scale selection in natural images. Furthermore, in the examples provided, the simplifying assumption is made that the behavior...... of the measurements is completely characterized by all moments up to second order....
Prediction of three dimensional maximum isometric neck strength.
Fice, Jason B; Siegmund, Gunter P; Blouin, Jean-Sébastien
2014-09-01
We measured maximum isometric neck strength under combinations of flexion/extension, lateral bending and axial rotation to determine whether neck strength in three dimensions (3D) can be predicted from principal axes strength. This would allow biomechanical modelers to validate their neck models across many directions using only principal axis strength data. Maximum isometric neck moments were measured in 9 male volunteers (29±9 years) for 17 directions. The 3D moments were normalized by the principal axis moments, and compared to unity for all directions tested. Finally, each subject's maximum principal axis moments were used to predict their resultant moment in the off-axis directions. Maximum moments were 30±6 N m in flexion, 32±9 N m in lateral bending, 51±11 N m in extension, and 13±5 N m in axial rotation. The normalized 3D moments were not significantly different from unity (95% confidence interval contained one), except for three directions that combined ipsilateral axial rotation and lateral bending; in these directions the normalized moments exceeded one. Predicted resultant moments compared well to the actual measured values (r2=0.88). Despite exceeding unity, the normalized moments were consistent across subjects to allow prediction of maximum 3D neck strength using principal axes neck strength.
F. TopsÃƒÂ¸e
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
Regularized maximum correntropy machine
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.
Principally Left Hereditary and Principally Left Strong Radicals
S. Tumurbat; R. Wiegandt
2001-01-01
A radical γ is normal if and only if γ is principally left hereditary and principally left strong (i.e., γ(L) = L e A and Lz ∈γ for all z ∈ L imply L γ(A)). Let a radical γ satisfy that A°∈γ and S° A° imply S°∈γ.Then γ is a hereditary normal radical if and only if γ is principally left strong and γ {A | (A, +,◇a) ∈γ a ∈ A}, where the multiplication ◇a is defined by x ◇a y ＝ xay. The Behrens radical class B is the largest principally left hereditary subclass of the Brown-McCoy radical class G. Neither3 nor G is principally left strong.
A novel limiting strain energy strength theory
LIU Guang-lian
2009-01-01
With applied dislocation theory,the effects of shear and normal stresses on the slide and climb motions at the same section of a crystal were analyzed.And,based on the synergetic effect of both normal and shear strain specific energies,the concept of the total equivalent strain specific energy (TESSE) at an oblique section and a new strength theory named as limiting strain energy strength theory (LSEST) were proposed.As for isotropic materials,the plastic yielding or brittle fracture of under uniaxial stress state would occur when the maximum TESSE reached the strain specific energy,also the expressions on the equivalent stresses and a function of failure of the LSEST under different principal stress states were obtained.Relationship formulas among the tensile,compressive and shear yield strengths for plastic metals were derived.These theoretical predictions,according to the LSEST,were consistent very well with experiment results of tensile,compressive and torsion tests of three plastic metals and other experiment results from open literatures.This novel LSEST might also help for strength calculation of other materials.
We Need Principals Who Understand.
Fineman, Sharon
1981-01-01
Describes the need for principals to have a greater understanding both of the needs of special education students and of effective ways of handling their problems. Special education survey courses and practical experiences for administrators might help close the gap between principals and special education teachers. (WD)
Time Management for New Principals
Ruder, Robert
2008-01-01
Becoming a principal is a milestone in an educator's professional life. The principalship is an opportunity to provide leadership that will afford students opportunities to thrive in a nurturing and supportive environment. Despite the continuously expanding demands of being a new principal, effective time management will enable an individual to be…
The Effective and Reflective Principal
Ritchie, John M.
2013-01-01
For a "Kappan" issue focusing on the job of the principal, this is an essay from a retired, longtime principal and superintendent. "I have notebooks full of advice that I've collected over the years: tips, mantras, cautions, and quotations appropriate for any occasion," the author says. "I learned to focus less on…
Burnout among Elementary School Principals
Combs, Julie; Edmonson, Stacey L.; Jackson, Sherion H.
2009-01-01
As the understanding of burnout continues to be refined, studies that examine school principals and burnout will be helpful to those who provide support to school leaders and are concerned about principal attrition and pending shortages. The purpose of this study was to examine the relationship between burnout and gender, age, and years experience…
What Principals Think Motivates Teachers
Diamantes, Thomas
2004-01-01
How did a graduate class of teachers and principals come to explore what was really important to teachers? They had an idea that they all shared the same values (both teachers and principals) and would agree on what rewards teachers prize. Would administrators rate the motivation rewards the same way the teachers would? To find out, five schools…
The Principal as Formative Coach
Nidus, Gabrielle; Sadder, Maya
2011-01-01
Formative coaching, an approach that uses student work as the foundation for mentoring and professional development, can help principals become more effective instructional leaders. In formative coaching, teaches and coaches analyze student work to determine next steps for instruction. This article shows how a principal can use the steps of the…
Principals and SRO's: Defining Roles.
Bond, Bill
2001-01-01
Many principals have recently acquired school resource officers, police officers who are stationed in schools and report to local sheriffs or police chiefs. Working effectively with a resource officer requires that principals and officers understand each other's role and express partnership details in a memorandum of understanding. (MLH)
The Principal as Adult Developer.
Levine, Sarah L.
1989-01-01
Restructuring of the principalship must include the principal's role as an adult developer aware of the inextricable link between teacher growth and student development. Principal and teacher should work together to learn how adults develop, to discover conditions fostering growth, and to encourage each other to face new challenges. (MLH)
Time Management for New Principals
Ruder, Robert
2008-01-01
Becoming a principal is a milestone in an educator's professional life. The principalship is an opportunity to provide leadership that will afford students opportunities to thrive in a nurturing and supportive environment. Despite the continuously expanding demands of being a new principal, effective time management will enable an individual to be…
Innovation Management Perceptions of Principals
Bakir, Asli Agiroglu
2016-01-01
This study is aimed to determine the perceptions of principals about innovation management and to investigate whether there is a significant difference in this perception according to various parameters. In the study, descriptive research model is used and universe is consisted from principals who participated in "Acquiring Formation Course…
Great Principals at Scale: Toolkit
Ikemoto, Gina; Taliaferro, Lori; Fenton, Benjamin; Davis, Jacquelyn
2014-01-01
School leaders are critical in the lives of students and to the development of their teachers. Unfortunately, in too many instances, principals are effective in spite of--rather than because of--district conditions. To truly improve student achievement for all students across the country, well-prepared principals need the tools, support, and…
Equalized near maximum likelihood detector
2012-01-01
This paper presents new detector that is used to mitigate intersymbol interference introduced by bandlimited channels. This detector is named equalized near maximum likelihood detector which combines nonlinear equalizer and near maximum likelihood detector. Simulation results show that the performance of equalized near maximum likelihood detector is better than the performance of nonlinear equalizer but worse than near maximum likelihood detector.
Cheeseman, Peter; Stutz, John
2005-01-01
A long standing mystery in using Maximum Entropy (MaxEnt) is how to deal with constraints whose values are uncertain. This situation arises when constraint values are estimated from data, because of finite sample sizes. One approach to this problem, advocated by E.T. Jaynes [1], is to ignore this uncertainty, and treat the empirically observed values as exact. We refer to this as the classic MaxEnt approach. Classic MaxEnt gives point probabilities (subject to the given constraints), rather than probability densities. We develop an alternative approach that assumes that the uncertain constraint values are represented by a probability density {e.g: a Gaussian), and this uncertainty yields a MaxEnt posterior probability density. That is, the classic MaxEnt point probabilities are regarded as a multidimensional function of the given constraint values, and uncertainty on these values is transmitted through the MaxEnt function to give uncertainty over the MaXEnt probabilities. We illustrate this approach by explicitly calculating the generalized MaxEnt density for a simple but common case, then show how this can be extended numerically to the general case. This paper expands the generalized MaxEnt concept introduced in a previous paper [3].
Undrained response of reconstituted clay to cyclic pure principal stress rotation
严佳佳; 周建; 龚晓南; 曹洋
2015-01-01
A series of monotonic and rotational shearing tests are carried out on reconstituted clay using a hollow cylinder apparatus under undrained condition. In the rotational shearing tests, the principal stress axes rotate cyclically with the magnitudes of the principal stresses keeping constant. The anisotropy of the reconstituted clay is analyzed from the monotonic shearing tests. Obvious pore pressure is induced by the principal stress rotation alone even with shear stress q0=5 kPa. Strain components also accumulate with increasing the number of cycles and increases suddenly at the onset of failure. The deviatoric shear strain of 7.5%can be taken as the failure criterion for clay subjected to the pure cyclic principal stress rotation. The intermediate principal stress parameter b plays a significant role in the development of pore pressure and strain. Specimens are weakened by cyclic rotational shearing as the shear modulus decreases with increasing the number of cycles, and the shear modulus reduces more quickly with larger b. Clear deviation between the directions of the principal plastic strain increment and the principal stress is observed during pure principal stress rotation. Both the coaxial and non-coaxial plastic mechanisms should be taken into consideration to simulate the deformation behavior of clay under pure principal stress rotation. The mechanism of the soil response to the pure principal stress rotation is discussed based on the experimental observations.
Principal -bundles on Nodal Curves
Usha N Bhosle
2001-08-01
Let be a connected semisimple affine algebraic group defined over . We study the relation between stable, semistable -bundles on a nodal curve and representations of the fundamental group of . This study is done by extending the notion of (generalized) parabolic vector bundles to principal -bundles on the desingularization of and using the correspondence between them and principal -bundles on . We give an isomorphism of the stack of generalized parabolic bundles on with a quotient stack associated to loop groups. We show that if is simple and simply connected then the Picard group of the stack of principal -bundles on is isomorphic to ⊕ , being the number of components of .
Principal metals online property data
Principal Metals is a leading supplier of specialty metals. This database contains complete materials property data on more than 5000 ferrous and non-ferrous materials (chemistry, mechanicals, general description, applications, welding, machining, an
Principal modes in fiber amplifiers
Fridman, Moti; Dubinskii, Mark; Friesem, Asher A; Davidson, Nir
2010-01-01
The dynamics of the state of polarization in single mode and multimode fiber amplifiers are presented. The experimental results reveal that although the state of polarizations at the output can vary over a large range when changing the temperatures of the fiber amplifiers, the variations are significantly reduced when resorting to the principal states of polarization in single mode fiber amplifiers and principal modes in multimode fiber amplifiers.
Principal Fibrations from Noncommutative Spheres
Landi, Giovanni; Suijlekom, Walter Van
2005-11-01
We construct noncommutative principal fibrations Sθ7→Sθ4 which are deformations of the classical SU(2) Hopf fibration over the four sphere. We realize the noncommutative vector bundles associated to the irreducible representations of SU(2) as modules of coequivariant maps and construct corresponding projections. The index of Dirac operators with coefficients in the associated bundles is computed with the Connes-Moscovici local index formula. "The algebra inclusion is an example of a not-trivial quantum principal bundle."
Giordano, Chiara; Kleiven, Svein
2014-11-01
Finite element (FE) models are often used to study the biomechanical effects of traumatic brain injury (TBI). Measures based on mechanical responses, such as principal strain or invariants of the strain tensor, are used as a metric to predict the risk of injury. However, the reliability of inferences drawn from these models depends on the correspondence between the mechanical measures and injury data, as well as the establishment of accurate thresholds of tissue injury. In the current study, a validated anisotropic FE model of the human head is used to evaluate the hypothesis that strain in the direction of fibers (axonal strain) is a better predictor of TBI than maximum principal strain (MPS), anisotropic equivalent strain (AESM) and cumulative strain damage measure (CSDM). An analysis of head kinematics-based metrics, such as head injury criterion (HIC) and brain injury criterion (BrIC), is also provided. Logistic regression analysis is employed to compare binary injury data (concussion/no concussion) with continuous strain/kinematics data. The threshold corresponding to 50% of injury probability is determined for each parameter. The predictive power (area under the ROC curve, AUC) is calculated from receiver operating characteristic (ROC) curve analysis. The measure with the highest AUC is considered to be the best predictor of mTBI. Logistic regression shows a statistical correlation between all the mechanical predictors and injury data for different regions of the brain. Peaks of axonal strain have the highest AUC and determine a strain threshold of 0.07 for corpus callosum and 0.15 for the brainstem, in agreement with previously experimentally derived injury thresholds for reversible axonal injury. For a data set of mild TBI from the national football league, the strain in the axonal direction is found to be a better injury predictor than MPS, AESM, CSDM, BrIC and HIC.
Li, Xibing; Du, Kun; Li, Diyuan
2015-11-01
True triaxial tests have been carried out on granite, sandstone and cement mortar using cubic specimens with the process of unloading the minor principal stress. The strengths and failure modes of the three rock materials are studied in the processes of unloading σ 3 and loading σ 1 by the newly developed true triaxial test system under different σ 2, aiming to study the mechanical responses of the rock in underground excavation at depth. It shows that the rock strength increases with the raising of the intermediate principal stress σ 2 when σ 3 is unloaded to zero. The true triaxial strength criterion by the power-law relationship can be used to fit the testing data. The "best-fitting" material parameters A and n ( A > 1.4 and n < 1.0) are almost located in the same range as expected by Al-Ajmi and Zimmerman (Int J Rock Mech Min Sci 563 42(3):431-439, 2005). It indicates that the end effect caused by the height-to-width ratio of the cubic specimens will not significantly affect the testing results under true triaxial tests. Both the strength and failure modes of cubic rock specimens under true triaxial unloading condition are affected by the intermediate principal stress. When σ 2 increases to a critical value for the strong and hard rocks (R4, R5 and R6), the rock failure mode may change from shear to slabbing. However, for medium strong and weak rocks (R3 and R2), even with a relatively high intermediate principal stress, they tend to fail in shear after a large amount of plastic deformation. The maximum extension strain criterion Stacey (Int J Rock Mech Min Sci Geomech Abstr 651 18(6):469-474, 1981) can be used to explain the change of failure mode from shear to slabbing for strong and hard rocks under true triaxial unloading test condition.
Early Career Principals: Working Productively with Difficult and Resistant Staff
Eller, John F.; Eller, Sheila A.
2012-01-01
Effective leaders must find ways to motivate their employees to provide maximum success for the organization. In today's world of high accountability, this ability is paramount to the success and survival of schools, and is an especially important skill for early career principals to master. Knowledge of the factors that might have contributed to…
Forming limit strains of interstitial free-IF steel sheet
Bressan, José Divo; Moreira, Luciano Pessanha; Freitas, Maria Carolina dos Santos
2016-10-01
Present work examines mathematical models to predict the onset of localized necking in sheet metal forming of interstitial free steel, such as biaxial stretching and deep drawing. Forming Limit Curve, FLC, which is an essential material parameter necessary to numerical simulation by FEM, of IF steel sheet was assessed experimentally by Nakajima testing and ASAME software. The "Map of Principal Surface Limit Strains - MPLS", shows the experimental FLC which is the plot of principal true strains in the sheet metal surface (ɛ1, ɛ2), occurring at critical points obtained in laboratory formability tests or in the fabrication process of parts. Two types of undesirable rupture mechanisms can occur in sheet metal forming products: localized necking and rupture by induced shear stress. Therefore, two kinds of limit strain curves can be plotted in the forming map: the local necking limit curve FLC-N and the shear stress rupture limit curve FLC-S. Localized necking is theoretically anticipated to occur by two mathematical models: Marciniak-Kuczynski modeling, hereafter named M-K approach, and D-Bressan modeling. In the M-K approach, local necking originates at an initial sheet thickness heterogeneity or defect fo = tob/toa. The strain state inside the evolving groove moves to plane strain and the limit strain ɛ1* is attained when the strain ɛ1a outside the groove or neck stop to increase. In the D-Bressan model, local necking is proposed to initiate at the instability point of maximum load, at a thickness defect (λ/μ)diffuse inside the grooved sheet thickness. The inception of visible grooving on the sheet surface evolves from instability point to localized (λ/μ)crit and final rupture, during further sheet metal straining. Work hardening law is defined for a strain and strain-rate material by the effective current stress. The average experimental hardening law curve for tensile tests at 0°, 45° and 90°, assuming normal anisotropy, was used to analyze the plasticity
Stress, strain rate and anisotropy in Kyushu, Japan
Savage, M. K.; Aoki, Y.; Unglert, K.; Ohkura, T.; Umakoshi, K.; Shimizu, H.; Iguchi, M.; Tameguri, T.; Ohminato, T.; Mori, J.
2016-04-01
correlate positively with stress ratio (c = 0.43, significant at 99% confidence). All three orientations are E-W in central Kyushu, where the compressional strain rate is highest. Both splitting and stress suggest plate-boundary-parallel maximum principal stress just off the coast of Kyushu, where strain rate measurements are sparse. South western Kyushu has the largest difference between directions of strain rate and stress. Φ from shallow and deep earthquakes are not well aligned, suggesting that the deep earthquake waveforms are not simply split in the crust. Causes for the anisotropy may be olivine crystals aligned by drag of the subducting Philippine Sea plate in the mantle and stress-aligned microcracks in the crust.
Attracting Principals to the Superintendency
Aimee Howley
2002-10-01
Full Text Available Responding to a perceived shortage of school superintendents in Ohio as well as elsewhere in the nation, this study examined the conditions of the job that make it attractive or unattractive as a career move for principals. The researchers surveyed a random sample of Ohio principals, receiving usable responses from 508 of these administrators. Analysis of the data revealed that principals perceived the ability to make a difference and the extrinsic motivators (e.g., salary and benefits associated with the superintendency as conditions salient to the decision to pursue such a job. Furthermore, they viewed the difficulties associated with the superintendency as extremely important. Among these difficulties, the most troubling were: (1 increased burden of responsibility for local, state, and federal mandates; (2 need to be accountable for outcomes that are beyond an educator’s control; (3 low levels of board support, and (4 excessive pressure to perform. The researchers also explored the personal and contextual characteristics that predisposed principals to see certain conditions of the superintendency as particularly attractive or particularly troublesome. Only two such characteristics, however, proved to be predictive: (1 principals with fewer years of teaching experience were more likely than their more experienced counterparts to rate the difficulty of the job as important to the decision to pursue a position as superintendent, and (2 principals who held cosmopolitan commitments were more likely than those who did not hold such commitments to view the salary and benefits associated with the superintendency as important. Findings from the study provided some guidance to those policy makers who are looking for ways to make the superintendency more attractive as a career move for principals. In particular, the study suggested that policy makers should work to design incentives that address school leaders’ interest in making a difference at the
Abdelahhad Barbour
Full Text Available BACKGROUND: Salivaricins are bacteriocins produced by Streptococcus salivarius, some strains of which can have significant probiotic effects. S. salivarius strains were isolated from Malaysian subjects showing variable antimicrobial activity, metabolic profile, antibiotic susceptibility and lantibiotic production. METHODOLOGY/PRINCIPAL FINDINGS: In this study we report new S. salivarius strains isolated from Malaysian subjects with potential as probiotics. Safety assessment of these strains included their antibiotic susceptibility and metabolic profiles. Genome sequencing using Illumina's MiSeq system was performed for both strains NU10 and YU10 and demonstrating the absence of any known streptococcal virulence determinants indicating that these strains are safe for subsequent use as probiotics. Strain NU10 was found to harbour genes encoding salivaricins A and 9 while strain YU10 was shown to harbour genes encoding salivaricins A3, G32, streptin and slnA1 lantibiotic-like protein. Strain GT2 was shown to harbour genes encoding a large non-lantibiotic bacteriocin (salivaricin-MPS. A new medium for maximum biomass production buffered with 2-(N-morpholinoethanesulfonic acid (MES was developed and showed better biomass accumulation compared with other commercial media. Furthermore, we extracted and purified salivaricin 9 (by strain NU10 and salivaricin G32 (by strain YU10 from S. salivarius cells grown aerobically in this medium. In addition to bacteriocin production, S. salivarius strains produced levan-sucrase which was detected by a specific ESI-LC-MS/MS method which indicates additional health benefits from the developed strains. CONCLUSION: The current study established the bacteriocin, levan-sucrase production and basic safety features of S. salivarius strains isolated from healthy Malaysian subjects demonstrating their potential for use as probiotics. A new bacteriocin-production medium was developed with potential scale up application for
Principal Curves on Riemannian Manifolds.
Hauberg, Soren
2016-09-01
Euclidean statistics are often generalized to Riemannian manifolds by replacing straight-line interpolations with geodesic ones. While these Riemannian models are familiar-looking, they are restricted by the inflexibility of geodesics, and they rely on constructions which are optimal only in Euclidean domains. We consider extensions of Principal Component Analysis (PCA) to Riemannian manifolds. Classic Riemannian approaches seek a geodesic curve passing through the mean that optimizes a criteria of interest. The requirements that the solution both is geodesic and must pass through the mean tend to imply that the methods only work well when the manifold is mostly flat within the support of the generating distribution. We argue that instead of generalizing linear Euclidean models, it is more fruitful to generalize non-linear Euclidean models. Specifically, we extend the classic Principal Curves from Hastie & Stuetzle to data residing on a complete Riemannian manifold. We show that for elliptical distributions in the tangent of spaces of constant curvature, the standard principal geodesic is a principal curve. The proposed model is simple to compute and avoids many of the pitfalls of traditional geodesic approaches. We empirically demonstrate the effectiveness of the Riemannian principal curves on several manifolds and datasets.
Principal Curves on Riemannian Manifolds
Hauberg, Søren
2015-01-01
Euclidean statistics are often generalized to Riemannian manifolds by replacing straight-line interpolations with geodesic ones. While these Riemannian models are familiar-looking, they are restricted by the inflexibility of geodesics, and they rely on constructions which are optimal only...... in Euclidean domains. We consider extensions of Principal Component Analysis (PCA) to Riemannian manifolds. Classic Riemannian approaches seek a geodesic curve passing through the mean that optimize a criteria of interest. The requirements that the solution both is geodesic and must pass through the mean tend...... from Hastie & Stuetzle to data residing on a complete Riemannian manifold. We show that for elliptical distributions in the tangent of spaces of constant curvature, the standard principal geodesic is a principal curve. The proposed model is simple to compute and avoids many of the pitfalls...
Strain rate orientations near the Coso Geothermal Field
Ogasa, N. T.; Kaven, J. O.; Barbour, A. J.; von Huene, R.
2016-12-01
Many geothermal reservoirs derive their sustained capacity for heat exchange in large part due to continuous deformation of preexisting faults and fractures that permit permeability to be maintained. Similarly, enhanced geothermal systems rely on the creation of suitable permeability from fracture and faults networks to be viable. Stress measurements from boreholes or earthquake source mechanisms are commonly used to infer the tectonic conditions that drive deformation, but here we show that geodetic data can also be used. Specifically, we quantify variations in the horizontal strain rate tensor in the area surrounding the Coso Geothermal Field (CGF) by analyzing more than two decades of high accuracy differential GPS data from a network of 14 stations from the University of Nevada Reno Geodetic Laboratory. To handle offsets in the data, from equipment changes and coseismic deformation, we segment the data, perform a piecewise linear fit and take the average of each segment's strain rate to determine secular velocities at each station. With respect to North America, all stations tend to travel northwest at velocities ranging from 1 to 10 mm/yr. The nearest station to CGF shows anomalous motion compared to regional stations, which otherwise show a coherent increase in network velocity from the northeast to the southwest. We determine strain rates via linear approximation using GPS velocities in Cartesian reference frame due to the small area of our network. Principal strain rate components derived from this inversion show maximum extensional strain rates of 30 nanostrain/a occur at N87W with compressional strain rates of 37nanostrain/a at N3E. These results generally align with previous stress measurements from borehole breakouts, which indicate the least compressive horizontal principal stress is east-west oriented, and indicative of the basin and range tectonic setting. Our results suggest that the CGF represents an anomaly in the crustal deformation field, which
Principal bundles the classical case
Sontz, Stephen Bruce
2015-01-01
This introductory graduate level text provides a relatively quick path to a special topic in classical differential geometry: principal bundles. While the topic of principal bundles in differential geometry has become classic, even standard, material in the modern graduate mathematics curriculum, the unique approach taken in this text presents the material in a way that is intuitive for both students of mathematics and of physics. The goal of this book is to present important, modern geometric ideas in a form readily accessible to students and researchers in both the physics and mathematics communities, providing each with an understanding and appreciation of the language and ideas of the other.
Surface analysis the principal techniques
Vickerman, John C
2009-01-01
This completely updated and revised second edition of Surface Analysis: The Principal Techniques, deals with the characterisation and understanding of the outer layers of substrates, how they react, look and function which are all of interest to surface scientists. Within this comprehensive text, experts in each analysis area introduce the theory and practice of the principal techniques that have shown themselves to be effective in both basic research and in applied surface analysis. Examples of analysis are provided to facilitate the understanding of this topic and to show readers how they c
Integrating Data Transformation in Principal Components Analysis
Maadooliat, Mehdi
2015-01-02
Principal component analysis (PCA) is a popular dimension reduction method to reduce the complexity and obtain the informative aspects of high-dimensional datasets. When the data distribution is skewed, data transformation is commonly used prior to applying PCA. Such transformation is usually obtained from previous studies, prior knowledge, or trial-and-error. In this work, we develop a model-based method that integrates data transformation in PCA and finds an appropriate data transformation using the maximum profile likelihood. Extensions of the method to handle functional data and missing values are also developed. Several numerical algorithms are provided for efficient computation. The proposed method is illustrated using simulated and real-world data examples.
School Uniforms: Guidelines for Principals.
Essex, Nathan L.
2001-01-01
Principals desiring to develop a school-uniform policy should involve parents, teachers, community leaders, and student representatives; beware restrictions on religious and political expression; provide flexibility and assistance for low-income families; implement a pilot program; align the policy with school-safety issues; and consider legal…
How Principals Support Teacher Effectiveness
Gallagher, Michael
2012-01-01
The current standards and accountability regime describes effective teaching as the ability to increase student achievement on standardized tests. This narrow definition of effectiveness can lead principals to create school cultures myopically focused on student achievement data. A "laser-like focus on academic achievement," if employed too…
Viotti, Matias R.; Armando Albertazzi, G. Jr.; Kapp, Walter A.
2011-03-01
This paper shows the optical setup of a radial in-plane digital speckle pattern interferometer which uses an axis-symmetrical diffractive optical element (DOE) to obtain double illumination. The application of the DOE gives in-plane sensitivity which only depends on the grating period of the DOE instead of the wavelength of the laser used as illumination source. A compact optical layout was built in order to have a portable optical strain sensor with a circular measurement area of about 5 mm in diameter. In order to compare its performance with electrical strain sensors (strain gauges), mechanical loading was generated by a four-point bending device and simultaneously monitored by the optical strain sensor and by two-element strain gauge rosettes. Several mechanical stress levels were measured showing a good agreement between both sensors. Results showed that the optical sensor could measure applied mechanical strains with a mean uncertainty of about 5% and 4% for the maximum and minimum principal strains, respectively.
Using Telecommunications for Principals' Professional Development.
Long, Claudia A.; Terry, Patricia D.
This paper describes the development, operations, and effectiveness of the Principals' Computer Network (PCN)--an experimental program created (1) to allow principals to use their schools' microcomputers to access other principals' solutions to common instructional management problems; (2) to enable principals to request suggestions from their…
Three Principals Who Make a Difference.
Sagor, Richard D.
1992-01-01
Principals who are transformative leaders consistently use three building blocks to promote school success: a clear, unified purpose; a common cultural perspective; and a constant push for improvement. In one study, an opinionated, assertive middle school principal; a nurturing, supportive principal; and a high-energy, charismatic principal all…
Inelastic strain in the seismogenic zone, Kyushu, Japan inferred from focal mechanism of earthquakes
Matsumoto, Satoshi; Nishimura, Takuya
2016-04-01
Strain in the seismogenic zone of the crust is a key parameter to understand crustal dynamics. GNSS data provide us with great information about deformation rate at the surface, which have been investigated by many researches and modeled kinematic behavior as elastic medium. Generally, strain in the earth's medium consists with elastic and inelastic ones. The two kinds of strain result different effects on the stress field. Therefore, detecting inelastic strain is important to know state of stress in the crust as well as elastic one. Inelastic strain is caused by such as fault creep, viscoelastic response, and earthquakes. Here, we showed the inelastic strain in the seismogenic zone of Kyushu, Japan from seismic moments and focal mechanisms data by counting Kostrov's sum in the spatial bins. Seismic moment tensors about 9000 earthquakes with magnitude greater than 2 for 13.5 years were obtained from seismic network data in Kyushu Island and F-net catalog. Total released moment at every spatial bin with 0.15 x 0.15 degree in latitude and longitude was estimated and then strain rate was calculated from the moment, compliance of the medium, and volume of the bin. The estimated maximum strain rate achieves 10^-7 strain/year. This strain rate is comparable with that from GNSS data. However, the strain rate mainly revealed the different principal direction from the one of GNSS. On the other hand, the directions were similar to the behavior of active faults in Kyushu. The result in this study showed that inelastic strain due to earthquakes is enough large, suggesting that the effect should be considered for modeling crustal dynamics.
OECD Maximum Residue Limit Calculator
With the goal of harmonizing the calculation of maximum residue limits (MRLs) across the Organisation for Economic Cooperation and Development, the OECD has developed an MRL Calculator. View the calculator.
Accurate structural correlations from maximum likelihood superpositions.
Douglas L Theobald
2008-02-01
Full Text Available The cores of globular proteins are densely packed, resulting in complicated networks of structural interactions. These interactions in turn give rise to dynamic structural correlations over a wide range of time scales. Accurate analysis of these complex correlations is crucial for understanding biomolecular mechanisms and for relating structure to function. Here we report a highly accurate technique for inferring the major modes of structural correlation in macromolecules using likelihood-based statistical analysis of sets of structures. This method is generally applicable to any ensemble of related molecules, including families of nuclear magnetic resonance (NMR models, different crystal forms of a protein, and structural alignments of homologous proteins, as well as molecular dynamics trajectories. Dominant modes of structural correlation are determined using principal components analysis (PCA of the maximum likelihood estimate of the correlation matrix. The correlations we identify are inherently independent of the statistical uncertainty and dynamic heterogeneity associated with the structural coordinates. We additionally present an easily interpretable method ("PCA plots" for displaying these positional correlations by color-coding them onto a macromolecular structure. Maximum likelihood PCA of structural superpositions, and the structural PCA plots that illustrate the results, will facilitate the accurate determination of dynamic structural correlations analyzed in diverse fields of structural biology.
吴志荣; 胡绪腾; 宋迎东
2013-01-01
工程中的大多构件承受着复杂的载荷形式,将单轴疲劳模型应用到多轴载荷情况已不能满足工程精度的要求,多轴载荷下的疲劳寿命计算日益引起人们的重视.基于临界平面的思想,结合Fatemi-Socie(FS)模型和Smith-Watson-Topper(SWT)参数各自的优点,提出一种新的多轴疲劳寿命预测模型.该模型以最大切应变幅与最大切应变幅平面上修正SWT参数的和作为多轴疲劳损伤控制参量,此参量可以同时考虑非比例附加循环硬化和平均应力对材料多轴疲劳寿命的影响,能同时适用于比例和非比例加载下的多轴疲劳问题.采用纯钛Ti、BT9钛合金、304不锈钢、S45C钢和1045HR钢5种材料多轴疲劳试验数据对提出的模型进行评估和验证,对几种材料比例和非比例加载下的多轴疲劳寿命预测结果大都分布在试验结果的2倍分散带之内,结果表明提出的多轴疲劳寿命模型具有较高的预测精度.%The most components of engineering structures are usually subjected to a complex loading. It is unable to meet the requirements of engineering precision if a uniaxial fatigue model is used under multi-axial loading. The calculation of fatigue life prediction under multiaxial loading causes people's attention more and more. A new multiaxial fatigue life prediction model is proposed based on the critical plane criteria. The model integrates the respective advantages of Fatemi-Socie(FS) model and Smith-Watson-Topper(SWT) parameter. The damage parameter in this model takes the sum of the maximum shear strain amplitude and the modified SWT parameter on the maximum shear strain amplitude plain. It can consider the effects of additional cyclic hardening due to non-proportional loading and mean stress on the multi-axial fatigue life of material. The proposed model can be applied to proportional and non-proportional loading. The model is evaluated by the multiaxial fatigue test data of pure titanium, BT9
Existence of a principal eigenvalue for the Tricomi problem
Daniela Lupo
2000-10-01
Full Text Available The existence of a principal eigenvalue is established for the Tricomi problem in normal domains; that is, the existence of a positive eigenvalue of minimum modulus with an associated positive eigenfunction. The argument here uses prior results of the authors on the generalized solvability in weighted Sobolev spaces and associated maximum/minimum principles cite{[LP2]} coupled with known results of Krein-Rutman type.
Fast Steerable Principal Component Analysis
Zhao, Zhizhen; Shkolnisky, Yoel; Singer, Amit
2016-01-01
Cryo-electron microscopy nowadays often requires the analysis of hundreds of thousands of 2D images as large as a few hundred pixels in each direction. Here we introduce an algorithm that efficiently and accurately performs principal component analysis (PCA) for a large set of two-dimensional images, and, for each image, the set of its uniform rotations in the plane and their reflections. For a dataset consisting of $n$ images of size $L \\times L$ pixels, the computational complexity of our a...
Principal chiral model on superspheres
Mitev, V.; Schomerus, V. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Quella, T. [Amsterdam Univ. (Netherlands). Inst. for Theoretical Physics
2008-09-15
We investigate the spectrum of the principal chiral model (PCM) on odd-dimensional superspheres as a function of the curvature radius R. For volume-filling branes on S{sup 3} {sup vertical} {sup stroke} {sup 2}, we compute the exact boundary spectrum as a function of R. The extension to higher dimensional superspheres is discussed, but not carried out in detail. Our results provide very convincing evidence in favor of the strong-weak coupling duality between supersphere PCMs and OSP(2S+2 vertical stroke 2S) Gross-Neveu models that was recently conjectured by Candu and Saleur. (orig.)
Maximum margin Bayesian network classifiers.
Pernkopf, Franz; Wohlmayr, Michael; Tschiatschek, Sebastian
2012-03-01
We present a maximum margin parameter learning algorithm for Bayesian network classifiers using a conjugate gradient (CG) method for optimization. In contrast to previous approaches, we maintain the normalization constraints on the parameters of the Bayesian network during optimization, i.e., the probabilistic interpretation of the model is not lost. This enables us to handle missing features in discriminatively optimized Bayesian networks. In experiments, we compare the classification performance of maximum margin parameter learning to conditional likelihood and maximum likelihood learning approaches. Discriminative parameter learning significantly outperforms generative maximum likelihood estimation for naive Bayes and tree augmented naive Bayes structures on all considered data sets. Furthermore, maximizing the margin dominates the conditional likelihood approach in terms of classification performance in most cases. We provide results for a recently proposed maximum margin optimization approach based on convex relaxation. While the classification results are highly similar, our CG-based optimization is computationally up to orders of magnitude faster. Margin-optimized Bayesian network classifiers achieve classification performance comparable to support vector machines (SVMs) using fewer parameters. Moreover, we show that unanticipated missing feature values during classification can be easily processed by discriminatively optimized Bayesian network classifiers, a case where discriminative classifiers usually require mechanisms to complete unknown feature values in the data first.
Maximum Entropy in Drug Discovery
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.
Using Kernel Principal Components for Color Image Segmentation
Wesolkowski, Slawo
2002-11-01
Distinguishing objects on the basis of color is fundamental to humans. In this paper, a clustering approach is used to segment color images. Clustering is usually done using a single point or vector as a cluster prototype. The data can be clustered in the input or feature space where the feature space is some nonlinear transformation of the input space. The idea of kernel principal component analysis (KPCA) was introduced to align data along principal components in the kernel or feature space. KPCA is a nonlinear transformation of the input data that finds the eigenvectors along which this data has maximum information content (or variation). The principal components resulting from KPCA are nonlinear in the input space and represent principal curves. This is a necessary step as colors in RGB are not linearly correlated especially considering illumination effects such as shading or highlights. The performance of the k-means (Euclidean distance-based) and Mixture of Principal Components (vector angle-based) algorithms are analyzed in the context of the input space and the feature space obtained using KPCA. Results are presented on a color image segmentation task. The results are discussed and further extensions are suggested.
Parametric functional principal component analysis.
Sang, Peijun; Wang, Liangliang; Cao, Jiguo
2017-03-10
Functional principal component analysis (FPCA) is a popular approach in functional data analysis to explore major sources of variation in a sample of random curves. These major sources of variation are represented by functional principal components (FPCs). Most existing FPCA approaches use a set of flexible basis functions such as B-spline basis to represent the FPCs, and control the smoothness of the FPCs by adding roughness penalties. However, the flexible representations pose difficulties for users to understand and interpret the FPCs. In this article, we consider a variety of applications of FPCA and find that, in many situations, the shapes of top FPCs are simple enough to be approximated using simple parametric functions. We propose a parametric approach to estimate the top FPCs to enhance their interpretability for users. Our parametric approach can also circumvent the smoothing parameter selecting process in conventional nonparametric FPCA methods. In addition, our simulation study shows that the proposed parametric FPCA is more robust when outlier curves exist. The parametric FPCA method is demonstrated by analyzing several datasets from a variety of applications. © 2017, The International Biometric Society.
Interpretable functional principal component analysis.
Lin, Zhenhua; Wang, Liangliang; Cao, Jiguo
2016-09-01
Functional principal component analysis (FPCA) is a popular approach to explore major sources of variation in a sample of random curves. These major sources of variation are represented by functional principal components (FPCs). The intervals where the values of FPCs are significant are interpreted as where sample curves have major variations. However, these intervals are often hard for naïve users to identify, because of the vague definition of "significant values". In this article, we develop a novel penalty-based method to derive FPCs that are only nonzero precisely in the intervals where the values of FPCs are significant, whence the derived FPCs possess better interpretability than the FPCs derived from existing methods. To compute the proposed FPCs, we devise an efficient algorithm based on projection deflation techniques. We show that the proposed interpretable FPCs are strongly consistent and asymptotically normal under mild conditions. Simulation studies confirm that with a competitive performance in explaining variations of sample curves, the proposed FPCs are more interpretable than the traditional counterparts. This advantage is demonstrated by analyzing two real datasets, namely, electroencephalography data and Canadian weather data.
Great Assistant Principals and the (Great) Principals Who Mentor Them: A Practical Guide
Goodman, Carole C.; Berry, Christopher S.
2011-01-01
Written for principals and assistant principals to read and reflect on together, this book describes the most common challenges facing today's assistant principals--and provides practical solutions. Authors Carole Goodman and Christopher Berry examine how principals and assistant principals can develop the kinds of relationships that serve to meet…
Great Assistant Principals and the (Great) Principals Who Mentor Them: A Practical Guide
Goodman, Carole C.; Berry, Christopher S.
2011-01-01
Written for principals and assistant principals to read and reflect on together, this book describes the most common challenges facing today's assistant principals--and provides practical solutions. Authors Carole Goodman and Christopher Berry examine how principals and assistant principals can develop the kinds of relationships that serve to meet…
Female Traditional Principals and Co-Principals: Experiences of Role Conflict and Job Satisfaction
Eckman, Ellen Wexler; Kelber, Sheryl Talcott
2010-01-01
This paper presents a secondary analysis of survey data focusing on role conflict and job satisfaction of 102 female principals. Data were collected from 51 female traditional principals and 51 female co-principals. By examining the traditional and co-principal leadership models as experienced by female principals, this paper addresses the impact…
Greenslade, Thomas B., Jr.
1985-01-01
Discusses a series of experiments performed by Thomas Hope in 1805 which show the temperature at which water has its maximum density. Early data cast into a modern form as well as guidelines and recent data collected from the author provide background for duplicating Hope's experiments in the classroom. (JN)
Abolishing the maximum tension principle
Dabrowski, Mariusz P
2015-01-01
We find the series of example theories for which the relativistic limit of maximum tension $F_{max} = c^2/4G$ represented by the entropic force can be abolished. Among them the varying constants theories, some generalized entropy models applied both for cosmological and black hole horizons as well as some generalized uncertainty principle models.
Abolishing the maximum tension principle
Mariusz P. Da̧browski
2015-09-01
Full Text Available We find the series of example theories for which the relativistic limit of maximum tension Fmax=c4/4G represented by the entropic force can be abolished. Among them the varying constants theories, some generalized entropy models applied both for cosmological and black hole horizons as well as some generalized uncertainty principle models.
Magellan: Principal Venus science findings
Saunders, R. Stephen
1993-01-01
This is a brief summary of the science findings of the Magellan mission, principally based on data from the radar system. Future plans for Magellan include acquisition of high resolution gravity data from a nearly circular orbit and atmospheric drag and occultation experiments. The Magellan science results represent the combined effort of more than 100 Magellan investigators and their students and colleagues. More extensive discussions can be found in the August and October, 1992 issues of the Journal of Geophysical Research, Planets. The Magellan mission's scientific objectives were to provide a global characterization of landforms and tectonic features; to distinguish and understand impact processes; to define and explain erosion, deposition, and chemical processes; and to model the interior density distribution. All but the last objective, which requires new global gravity data, have been accomplished, or we have acquired the data that are required to accomplish them.
Fast Steerable Principal Component Analysis.
Zhao, Zhizhen; Shkolnisky, Yoel; Singer, Amit
2016-03-01
Cryo-electron microscopy nowadays often requires the analysis of hundreds of thousands of 2-D images as large as a few hundred pixels in each direction. Here, we introduce an algorithm that efficiently and accurately performs principal component analysis (PCA) for a large set of 2-D images, and, for each image, the set of its uniform rotations in the plane and their reflections. For a dataset consisting of n images of size L × L pixels, the computational complexity of our algorithm is O(nL(3) + L(4)), while existing algorithms take O(nL(4)). The new algorithm computes the expansion coefficients of the images in a Fourier-Bessel basis efficiently using the nonuniform fast Fourier transform. We compare the accuracy and efficiency of the new algorithm with traditional PCA and existing algorithms for steerable PCA.
Hu, W; Hu, Wayne; Okamoto, Takemi
2004-01-01
We study the physical limitations placed on CMB temperature and polarization measurements of the initial power spectrum by geometric projection, acoustic physics, gravitational lensing and the joint fitting of cosmological parameters. Detailed information on the spectrum is greatly assisted by polarization information and localized to the acoustic regime k = 0.02-0.2 Mpc^{-1} with a fundamental resolution of Delta k/k>0.05. From this study we construct principal component based statistics, which are orthogonal to cosmological parameters including the initial amplitude and tilt of the spectrum, that best probe deviations from scale-free initial conditions. These statistics resemble Fourier modes confined to the acoustic regime and ultimately can yield ~50 independent measurements of the power spectrum features to percent level precision. They are straightforwardly related to more traditional parameterizations such as the the running of the tilt and in the future can provide many statistically independent measu...
2010-01-01
... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Principal. 919.995 Section 919.995 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 919.995 Principal. Principal means— (a) An...
12 CFR 561.39 - Principal office.
2010-01-01
... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Principal office. 561.39 Section 561.39 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY DEFINITIONS FOR REGULATIONS AFFECTING ALL SAVINGS ASSOCIATIONS § 561.39 Principal office. The term principal office means the...
New Principal Coaching as a Safety Net
Celoria, Davide; Roberson, Ingrid
2015-01-01
This study examines new principal coaching as an induction process and explores the emotional dimensions of educational leadership. Twelve principal coaches and new principals--six of each--participated in this qualitative study that employed emergent coding (Creswell, 2008; Denzin, 2005; Glaser & Strauss, 1998; Spradley, 1979). The major…
Teacher Supervision Practices and Principals' Characteristics
April, Daniel; Bouchamma, Yamina
2015-01-01
A questionnaire was used to determine the individual and collective teacher supervision practices of school principals and vice-principals in Québec (n = 39) who participated in a research-action study on pedagogical supervision. These practices were then analyzed in terms of the principals' sociodemographic and socioprofessional characteristics…
A principal-agent model of corruption
Groenendijk, Nico
1997-01-01
One of the new avenues in the study of political corruption is that of neo-institutional economics, of which the principal-agent theory is a part. In this article a principal-agent model of corruption is presented, in which there are two principals (one of which is corrupting), and one agent (who is
Maximum Genus of Strong Embeddings
Er-ling Wei; Yan-pei Liu; Han Ren
2003-01-01
The strong embedding conjecture states that any 2-connected graph has a strong embedding on some surface. It implies the circuit double cover conjecture: Any 2-connected graph has a circuit double cover.Conversely, it is not true. But for a 3-regular graph, the two conjectures are equivalent. In this paper, a characterization of graphs having a strong embedding with exactly 3 faces, which is the strong embedding of maximum genus, is given. In addition, some graphs with the property are provided. More generally, an upper bound of the maximum genus of strong embeddings of a graph is presented too. Lastly, it is shown that the interpolation theorem is true to planar Halin graph.
Remizov, Ivan D
2009-01-01
In this note, we represent a subdifferential of a maximum functional defined on the space of all real-valued continuous functions on a given metric compact set. For a given argument, $f$ it coincides with the set of all probability measures on the set of points maximizing $f$ on the initial compact set. This complete characterization lies in the heart of several important identities in microeconomics, such as Roy's identity, Sheppard's lemma, as well as duality theory in production and linear programming.
The Testability of Maximum Magnitude
Clements, R.; Schorlemmer, D.; Gonzalez, A.; Zoeller, G.; Schneider, M.
2012-12-01
Recent disasters caused by earthquakes of unexpectedly large magnitude (such as Tohoku) illustrate the need for reliable assessments of the seismic hazard. Estimates of the maximum possible magnitude M at a given fault or in a particular zone are essential parameters in probabilistic seismic hazard assessment (PSHA), but their accuracy remains untested. In this study, we discuss the testability of long-term and short-term M estimates and the limitations that arise from testing such rare events. Of considerable importance is whether or not those limitations imply a lack of testability of a useful maximum magnitude estimate, and whether this should have any influence on current PSHA methodology. We use a simple extreme value theory approach to derive a probability distribution for the expected maximum magnitude in a future time interval, and we perform a sensitivity analysis on this distribution to determine if there is a reasonable avenue available for testing M estimates as they are commonly reported today: devoid of an appropriate probability distribution of their own and estimated only for infinite time (or relatively large untestable periods). Our results imply that any attempt at testing such estimates is futile, and that the distribution is highly sensitive to M estimates only under certain optimal conditions that are rarely observed in practice. In the future we suggest that PSHA modelers be brutally honest about the uncertainty of M estimates, or must find a way to decrease its influence on the estimated hazard.
Alternative Multiview Maximum Entropy Discrimination.
Chao, Guoqing; Sun, Shiliang
2016-07-01
Maximum entropy discrimination (MED) is a general framework for discriminative estimation based on maximum entropy and maximum margin principles, and can produce hard-margin support vector machines under some assumptions. Recently, the multiview version of MED multiview MED (MVMED) was proposed. In this paper, we try to explore a more natural MVMED framework by assuming two separate distributions p1( Θ1) over the first-view classifier parameter Θ1 and p2( Θ2) over the second-view classifier parameter Θ2 . We name the new MVMED framework as alternative MVMED (AMVMED), which enforces the posteriors of two view margins to be equal. The proposed AMVMED is more flexible than the existing MVMED, because compared with MVMED, which optimizes one relative entropy, AMVMED assigns one relative entropy term to each of the two views, thus incorporating a tradeoff between the two views. We give the detailed solving procedure, which can be divided into two steps. The first step is solving our optimization problem without considering the equal margin posteriors from two views, and then, in the second step, we consider the equal posteriors. Experimental results on multiple real-world data sets verify the effectiveness of the AMVMED, and comparisons with MVMED are also reported.
Principal component regression analysis with SPSS.
Liu, R X; Kuang, J; Gong, Q; Hou, X L
2003-06-01
The paper introduces all indices of multicollinearity diagnoses, the basic principle of principal component regression and determination of 'best' equation method. The paper uses an example to describe how to do principal component regression analysis with SPSS 10.0: including all calculating processes of the principal component regression and all operations of linear regression, factor analysis, descriptives, compute variable and bivariate correlations procedures in SPSS 10.0. The principal component regression analysis can be used to overcome disturbance of the multicollinearity. The simplified, speeded up and accurate statistical effect is reached through the principal component regression analysis with SPSS.
Ritter, Malte C.; Rosenau, Matthias; Leever, Karen; Oncken, Onno
2014-05-01
. Therefore simultaneous monitoring and analysis of strain weakening and strain localisation becomes feasible. Here we present results from first tests of this setup demonstrating its capability and limits. Various granular analogue materials with differing mechanical properties are tested and compared to results in ring shear and axial tests. Preliminary results show a principal pattern of correlated strain weakening and localisation that is characterized by a phase shift between stress and strain evolution during shear zone formation: Strain localisation has its maximum when the weakening rate is highest. Strain then delocalises, however, and reaches a steady state when the material strength reaches a stable value. References: Lohrmann, J., Kukowski, N., Adam, J., and Oncken, O., 2003, The impact of analogue material properties on the geometry, kinematics, and dynamics of convergent sand wedges: Journal of Structural Geology, v. 25, no. 10, p. 1691-1711, doi: 10.1016/S0191-8141(03)00005-1. Schrank, C.E., Boutelier, D.A., and Cruden, A.R., 2008, The analogue shear zone: From rheology to associated geometry: Journal of Structural Geology, v. 30, no. 2, p. 177-193, doi: 10.1016/j.jsg.2007.11.002.
Cacti with maximum Kirchhoff index
Wang, Wen-Rui; Pan, Xiang-Feng
2015-01-01
The concept of resistance distance was first proposed by Klein and Randi\\'c. The Kirchhoff index $Kf(G)$ of a graph $G$ is the sum of resistance distance between all pairs of vertices in $G$. A connected graph $G$ is called a cactus if each block of $G$ is either an edge or a cycle. Let $Cat(n;t)$ be the set of connected cacti possessing $n$ vertices and $t$ cycles, where $0\\leq t \\leq \\lfloor\\frac{n-1}{2}\\rfloor$. In this paper, the maximum kirchhoff index of cacti are characterized, as well...
Generic maximum likely scale selection
Pedersen, Kim Steenstrup; Loog, Marco; Markussen, Bo
2007-01-01
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...... on second order moments of multiple measurements outputs at a fixed location. These measurements, which reflect local image structure, consist in the cases considered here of Gaussian derivatives taken at several scales and/or having different derivative orders....
Economics and Maximum Entropy Production
Lorenz, R. D.
2003-04-01
Price differentials, sales volume and profit can be seen as analogues of temperature difference, heat flow and work or entropy production in the climate system. One aspect in which economic systems exhibit more clarity than the climate is that the empirical and/or statistical mechanical tendency for systems to seek a maximum in production is very evident in economics, in that the profit motive is very clear. Noting the common link between 1/f noise, power laws and Self-Organized Criticality with Maximum Entropy Production, the power law fluctuations in security and commodity prices is not inconsistent with the analogy. There is an additional thermodynamic analogy, in that scarcity is valued. A commodity concentrated among a few traders is valued highly by the many who do not have it. The market therefore encourages via prices the spreading of those goods among a wider group, just as heat tends to diffuse, increasing entropy. I explore some empirical price-volume relationships of metals and meteorites in this context.
Sparse Principal Component Analysis with missing observations
Lounici, Karim
2012-01-01
In this paper, we study the problem of sparse Principal Component Analysis (PCA) in the high-dimensional setting with missing observations. Our goal is to estimate the first principal component when we only have access to partial observations. Existing estimation techniques are usually derived for fully observed data sets and require a prior knowledge of the sparsity of the first principal component in order to achieve good statistical guarantees. Our contributions is threefold. First, we establish the first information-theoretic lower bound for the sparse PCA problem with missing observations. Second, we propose a simple procedure that does not require any prior knowledge on the sparsity of the unknown first principal component or any imputation of the missing observations, adapts to the unknown sparsity of the first principal component and achieves the optimal rate of estimation up to a logarithmic factor. Third, if the covariance matrix of interest admits a sparse first principal component and is in additi...
Franz, Eelco; van Hoek, Angela H. A. M.; Bouw, El; Aarts, Henk J. M.
2011-01-01
The variation in manure-amended soil survival capability among 18 Escherichia coli O157 strains (8 animal, 1 food, and 9 human isolates) was studied using a single sandy soil sample and a single sample of cattle manure as the inoculum carrier. The virulence profiles of E. coli O157 strains were characterized by detection of virulence determinants (73 genes, 122 probes in duplicate) by using the Identibac E. coli genotyping DNA miniaturized microarray. Metabolic profiling was done by subjecting all strains to the Biolog phenotypic carbon microarray. Survival times (calculated as days needed to reach the detection limit using the Weibull model) ranged from 47 to 266 days (median, 120 days). Survival time was significantly higher for the group of human isolates (median, 211 days; minimum [min.], 71; maximum [max.], 266) compared to the group of animal isolates (median, 70 days; min., 47; max., 249) (P = 0.025). Although clustering of human versus animal strains was observed based on pulsed-field gel electrophoresis (PFGE) patterns, no relation between survival time and the presence of virulence genes was observed. Principal component analysis on the metabolic profiling data revealed distinct clustering of short- and long-surviving strains. The oxidization rate of propionic acid, α-ketobutyric acid, and α-hydroxybutyric acid was significantly higher for the long-surviving strains than for the short-surviving strains. The oxidative capacity of E. coli O157 strains may be regarded as a phenotypic marker for enhanced survival in manure-amended soil. The large variation observed in survival is of importance for risk assessment models. PMID:21908630
Objects of maximum electromagnetic chirality
Fernandez-Corbaton, Ivan
2015-01-01
We introduce a definition of the electromagnetic chirality of an object and show that it has an upper bound. The upper bound is attained if and only if the object is transparent for fields of one handedness (helicity). Additionally, electromagnetic duality symmetry, i.e. helicity preservation upon scattering, turns out to be a necessary condition for reciprocal scatterers to attain the upper bound. We use these results to provide requirements for the design of such extremal scatterers. The requirements can be formulated as constraints on the polarizability tensors for dipolar scatterers or as material constitutive relations. We also outline two applications for objects of maximum electromagnetic chirality: A twofold resonantly enhanced and background free circular dichroism measurement setup, and angle independent helicity filtering glasses.
Maximum mutual information regularized classification
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.
Wang Sheng-zu
2006-01-01
According to the "Netlike Plastic-Flow (NPF)" continental dynamics model, the transition of the deformation regime from brittle in shallow layers to ductile in deep layers in the lithosphere, and the controlling effect of NPF in the lower lithosphere result in intraplate multilayer tectonic deformation. NPF is a viscous (plastic) flow accompanied by shear strain localization, forming a plastic-flow network in the lower lithosphere. The strain rates in the seismogenic layer can be estimated using the "earthquake-recurrence-interval" method, in which the strain rate is calculated in terms of the recurrence interval of two sequential carthquakes and the seismic probability of the second earthquake. The strains in the lower lithosphere are estimated using the "conjugate-angle" method, which takes the relationship between the conjugate angles and the compressive strains of the network, and calculates the characteristic strain rates in this layer from the strains and the durations of deformation inferred. The contour map of characteristic maximum principal compressive strain rates in the lower lithosphere in central-eastern Asia given in the paper shows strain rates with magnitudes on the order of 10-15 ～ 10-14/s in this region. The strain rates within the plastic-flow belts,which control seismic activities in the seismogenic layer, are greater than the characteristic strain rates of the network and, in addition, the strain rates and seismic activities in the seismogenic layer are also influenced by other factors, including the directive action of driving boundary along the upper crust, the effects of plastic-flow waves and the existence of the transitional weak layer distributed discontinuously between the upper and lower layers. The comparison between the strain rates in the seismogenic layer and the characteristic strain rates in the lower lithosphere for 11 potential hypocenter areas in the region from the Qinghai-Xizang (Tibet) plateau to the North China plain
Untapped Resources: Assistant Principals as Instructional Leaders
Bartholomew, Selma K.; Melendez-Delaney, Genis; Orta, Awilda; White, Sharon
2005-01-01
Assistant principals are often overlooked as a resource for creating, advancing, and sustaining a compelling vision for mathematics. The Math Collaborative Project developed in New York City examined the process of developing and implementing programs designed to help assistant principals network and strengthen their instructional leadership…
New Principals' Perspectives of Their Multifaceted Roles
Gentilucci, James L.; Denti, Lou; Guaglianone, Curtis L.
2013-01-01
This study utilizes Symbolic Interactionism to explore perspectives of neophyte principals. Findings explain how these perspectives are modified through complex interactions throughout the school year, and they also suggest preparation programs can help new principals most effectively by teaching "soft" skills such as active listening…
Perceived Educational Values of Omani School Principals
Al-Ani, Wajeha Thabit; Al-Harthi, Aisha Salim
2017-01-01
This qualitative study investigated the perceived educational values of Omani school principals. Data were collected using a semi-structured interview form which focused on the core values of school administration as perceived by a sample of 44 school principals; a focus group interview was also held. Data were analysed using Nvivo software. The…
Principals: Human Capital Managers at Every School
Kimball, Steven M.
2011-01-01
Being a principal is more than just being an instructional leader. Principals also must manage their schools' teaching talent in a strategic way so that it is linked to school instructional improvement strategies, to the competencies needed to enact the strategies, and to success in boosting student learning. Teacher acquisition and performance…
Assistant Principals: Their Readiness as Instructional Leaders
Searby, Linda; Browne-Ferrigno, Tricia; Wang, Chih-hsuan
2017-01-01
This article reports findings from a study investigating the capacity of assistant principals to be instructional leaders. Analyses of survey responses yielded four interesting findings: (a) years of experience as a teacher and age had no significance on assistant principals' perceived readiness as an instructional leader; (b) those completing…
Career Paths of Female Elementary Assistant Principals
Baier, Hope C.
2013-01-01
The purpose of this research was to explore the worklife experiences and personal issues of female elementary assistant principals and examine the influence of these factors on their intent to remain in their position or leave. The worklife experiences and perceptions of female elementary assistant principals were categorized as institutional or…
Assistant Principals and Reform: A Socialization Paradox?
Best, Marguerita L.
2013-01-01
Framed in the critical race theory of structuration (CRTS), this sequential explanatory mixed methods study seeks to identify the socialization practices by examining the realities of practices of assistant principals and the ways in which they impact the disciplinary actions of assistant principals at middle and high schools. The mixed methods…
Principals as Maverick Leaders: Rethinking Democratic Schools
Walker, Sharron Goldman; Chirichello, Michael
2011-01-01
After her school wins the coveted United States National Secondary Education Award, a school principal embarks upon an educational odyssey. The principal discovers that the reasons for winning the award are a sham! As her school falls apart, she begins to reflect on the stagnant school organization and the ineffective prescriptions for…
Principals' Perceptions of School Public Relations
Morris, Robert C.; Chan, Tak Cheung; Patterson, Judith
2009-01-01
This study was designed to investigate school principals' perceptions on school public relations in five areas: community demographics, parental involvement, internal and external communications, school council issues, and community resources. Findings indicated that principals' concerns were as follows: rapid population growth, change of…
Principals' Pupil Control Behavior and School Robustness.
Smedley, Stanley R.; Willower, Donald J.
1981-01-01
A survey of 3,100 students, teachers, and principals in 47 elementary and secondary schools in the Middle Atlantic region, using the Pupil Control Behavior Form, revealed a positive association between principals' humanistic pupil control behavior and schools'"robustness" (the degree of meaning and excitement students find in school).…
Geographical Distribution of Principals in Israeli Schools
Lebental, Dana M.
2015-01-01
This quantitative investigation focuses on women high school principals at Jewish secular schools throughout Israel. Despite challenges, Israeli women have succeeded in obtaining over half of the principal positions at Jewish secular high schools, but the degree to which there is equal gender access to leadership roles in the school system remains…
Principals: Human Capital Managers at Every School
Kimball, Steven M.
2011-01-01
Being a principal is more than just being an instructional leader. Principals also must manage their schools' teaching talent in a strategic way so that it is linked to school instructional improvement strategies, to the competencies needed to enact the strategies, and to success in boosting student learning. Teacher acquisition and performance…
A Latina Principal Leading for Social Justice
Hernandez, Frank; Murakami, Elizabeth T.; Cerecer, Patricia Quijada
2014-01-01
In this study, the role that racial identity plays among Latina school principals is examined through a case study of a principal in a K-3 elementary school. Based on a Latina/o critical race framework and a phenomenological research approach, the study explores the degree to which having a strong understanding of one's racial identity…
Instructional Leadership: Are Women Principals Better?
Andrews, Richard L.; Basom, Margaret R.
1990-01-01
A 1984 study found that female elementary school principals spent 38.4 percent of their time on instructional leadership activities, while their male counterparts spent only 21.8 percent. A 1989 follow-up study found that women principals were more likely to be seen by their staffs as instructional leaders. A sidebar examines sex discrimination in…
Evaluation of Principals; Leadership Excellence Achievement Plan.
Redfern, George B.; Hersey, Paul W.
1981-01-01
The Leadership Excellence Achievement Plan (LEAP) presented here is a way for principals to improve leadership ability with an emphasis on evaluation. It first recommends formulating a precise definition of the principal's job divided into three areas: technical competencies, administrative skills, and performance goals. Among the technical…
Assistant Principals and Reform: A Socialization Paradox?
Best, Marguerita L.
2013-01-01
Framed in the critical race theory of structuration (CRTS), this sequential explanatory mixed methods study seeks to identify the socialization practices by examining the realities of practices of assistant principals and the ways in which they impact the disciplinary actions of assistant principals at middle and high schools. The mixed methods…
Micropolitics: Empowering Principals to Accomplish Goals.
Cilo, Daniel C.
1994-01-01
Examines how principals manage in situations that defy conventional administrative authority and methods. Fully 80% of the 30 Pennsylvania high school principals interviewed admitted using at least 1 micropolitical strategy, such as exchange theory, divide and conquer, information control, cooptation, displacement, and discretionary behavior. Most…
Elementary Principals' Role in Science Instruction
Casey, Patricia; Dunlap, Karen; Brown, Kristen; Davison, Michele
2012-01-01
This study explores the role elementary school principals play in science education. Specifically, the study employed an online survey of 16 elementary school principals at high-performing campuses in North Texas to explore their perceptions of how they influenced science education on their campuses. The survey used a combination of Likert-type…
Permutation Tests in Principal Component Analysis.
Pohlmann, John T.; Perkins, Kyle; Brutten, Shelia
Structural changes in an English as a Second Language (ESL) 30-item reading comprehension test were examined through principal components analysis on a small sample (n=31) of students. Tests were administered on three occasions during intensive ESL training. Principal components analysis of the items was performed for each test occasion.…
Social Media Strategies for School Principals
Cox, Dan; McLeod, Scott
2014-01-01
The purpose of this qualitative study was to describe, analyze, and interpret the experiences of school principals who use multiple social media tools with stakeholders as part of their comprehensive communications practices. Additionally, it examined why school principals have chosen to communicate with their stakeholders through social media.…
Women Principals Leading Learning at "Poverty's Edge"
Lyman, Linda L.
2008-01-01
The author profiles two women principals of color who have successfully enhanced student learning in high-poverty schools. In their leadership narratives, the principals address how the complexity of poverty affects their work, how they affirm the worth and dignity of all, how they influence beliefs and attitudes of staff, why they think their…
Women Principals Leading Learning at "Poverty's Edge"
Lyman, Linda L.
2008-01-01
The author profiles two women principals of color who have successfully enhanced student learning in high-poverty schools. In their leadership narratives, the principals address how the complexity of poverty affects their work, how they affirm the worth and dignity of all, how they influence beliefs and attitudes of staff, why they think their…
Instructional or Managerial Leadership: The Principal Role!
Jazzar, Michael
2004-01-01
"Instructional Or Managerial Leadership: The Principal Role" is a case study written to challenge the beliefs of graduate students preparing for educational leadership roles and educational leaders already in these positions as to the importance of the principal as an instructional leader. This case explores communication between superintendents…
A Latina Principal Leading for Social Justice
Hernandez, Frank; Murakami, Elizabeth T.; Cerecer, Patricia Quijada
2014-01-01
In this study, the role that racial identity plays among Latina school principals is examined through a case study of a principal in a K-3 elementary school. Based on a Latina/o critical race framework and a phenomenological research approach, the study explores the degree to which having a strong understanding of one's racial identity formation…
Superintendents' Perceptions of the Principal Shortage
Pijanowski, John C.; Hewitt, Paul M.; Brady, Kevin P.
2009-01-01
The research literature on the principal shortage is inconsistent regarding the actual scope of the shortage and a clear articulation of factors contributing to the successful recruitment and retention of today's school leaders. Often, critical data related to the principal shortage are ignored, including the number of younger principals…
Exploring Principals' Perceptions of Supervised Agricultural Experience
Rayfield, John; Wilson, Elizabeth
2009-01-01
This study explored the perceptions of principals at high schools with agricultural education programs in regard to Supervised Agricultural Experience (SAE). There is evidence that suggests that high school principals' attitudes may both directly and indirectly affect factors that influence school climate and student achievement. In this study,…
Investigating Roles of Online School Principals
Quilici, Sarah B.; Joki, Russell
2012-01-01
This study explores the instructional leadership skills required from online principals, as defined by one state's (Idaho) adaptation of the Interstate School Leaders Licensure Consortium (ISLLC) standards (1996) as a requirement for professional certification. Specifically, this qualitative study examined six sets of paired online principals and…
School Principal Speech about Fiscal Mismanagement
Hassenpflug, Ann
2015-01-01
A review of two recent federal court cases concerning school principals who experienced adverse job actions after they engaged in speech about fiscal misconduct by other employees indicates that the courts found that the principal's speech was made as part of his or her job duties and was not protected by the First Amendment.
Social Media Strategies for School Principals
Cox, Dan; McLeod, Scott
2014-01-01
The purpose of this qualitative study was to describe, analyze, and interpret the experiences of school principals who use multiple social media tools with stakeholders as part of their comprehensive communications practices. Additionally, it examined why school principals have chosen to communicate with their stakeholders through social media.…
Estimating Principal Effectiveness. Working Paper 32
Branch, Gregory; Hanushek, Eric; Rivkin, Steven
2009-01-01
Much has been written about the importance of school leadership, but there is surprisingly little systematic evidence on this topic. This paper presents preliminary estimates of key elements of the market for school principals, employing rich panel data on principals from Texas State. The consideration of teacher movements across schools suggests…
Framing Research on School Principals' Identities
Crow, Gary; Day, Christopher; Møller, Jorunn
2017-01-01
This paper provides a basis for a tentative framework for guiding future research into principals' identity construction and development. It is situated in the context of persisting emphases placed by government policies on the need for technocratic competencies in principals as a means of demonstrating success defined largely as compliance with…
Should Principals Know More about Law?
Doctor, Tyrus L.
2013-01-01
Educational law is a critical piece of the education conundrum. Principals reference law books on a daily basis in order to address the wide range of complex problems in the school system. A principal's knowledge of law issues and legal decision-making are essential to provide effective feedback for a successful school.
Principals as Maverick Leaders: Rethinking Democratic Schools
Walker, Sharron Goldman; Chirichello, Michael
2011-01-01
After her school wins the coveted United States National Secondary Education Award, a school principal embarks upon an educational odyssey. The principal discovers that the reasons for winning the award are a sham! As her school falls apart, she begins to reflect on the stagnant school organization and the ineffective prescriptions for…
Maximum entropy production in daisyworld
Maunu, Haley A.; Knuth, Kevin H.
2012-05-01
Daisyworld was first introduced in 1983 by Watson and Lovelock as a model that illustrates how life can influence a planet's climate. These models typically involve modeling a planetary surface on which black and white daisies can grow thus influencing the local surface albedo and therefore also the temperature distribution. Since then, variations of daisyworld have been applied to study problems ranging from ecological systems to global climate. Much of the interest in daisyworld models is due to the fact that they enable one to study self-regulating systems. These models are nonlinear, and as such they exhibit sensitive dependence on initial conditions, and depending on the specifics of the model they can also exhibit feedback loops, oscillations, and chaotic behavior. Many daisyworld models are thermodynamic in nature in that they rely on heat flux and temperature gradients. However, what is not well-known is whether, or even why, a daisyworld model might settle into a maximum entropy production (MEP) state. With the aim to better understand these systems, this paper will discuss what is known about the role of MEP in daisyworld models.
Maximum stellar iron core mass
F W Giacobbe
2003-03-01
An analytical method of estimating the mass of a stellar iron core, just prior to core collapse, is described in this paper. The method employed depends, in part, upon an estimate of the true relativistic mass increase experienced by electrons within a highly compressed iron core, just prior to core collapse, and is signiﬁcantly different from a more typical Chandrasekhar mass limit approach. This technique produced a maximum stellar iron core mass value of 2.69 × 1030 kg (1.35 solar masses). This mass value is very near to the typical mass values found for neutron stars in a recent survey of actual neutron star masses. Although slightly lower and higher neutron star masses may also be found, lower mass neutron stars are believed to be formed as a result of enhanced iron core compression due to the weight of non-ferrous matter overlying the iron cores within large stars. And, higher mass neutron stars are likely to be formed as a result of fallback or accretion of additional matter after an initial collapse event involving an iron core having a mass no greater than 2.69 × 1030 kg.
Maximum Matchings via Glauber Dynamics
Jindal, Anant; Pal, Manjish
2011-01-01
In this paper we study the classic problem of computing a maximum cardinality matching in general graphs $G = (V, E)$. The best known algorithm for this problem till date runs in $O(m \\sqrt{n})$ time due to Micali and Vazirani \\cite{MV80}. Even for general bipartite graphs this is the best known running time (the algorithm of Karp and Hopcroft \\cite{HK73} also achieves this bound). For regular bipartite graphs one can achieve an $O(m)$ time algorithm which, following a series of papers, has been recently improved to $O(n \\log n)$ by Goel, Kapralov and Khanna (STOC 2010) \\cite{GKK10}. In this paper we present a randomized algorithm based on the Markov Chain Monte Carlo paradigm which runs in $O(m \\log^2 n)$ time, thereby obtaining a significant improvement over \\cite{MV80}. We use a Markov chain similar to the \\emph{hard-core model} for Glauber Dynamics with \\emph{fugacity} parameter $\\lambda$, which is used to sample independent sets in a graph from the Gibbs Distribution \\cite{V99}, to design a faster algori...
2011-01-10
...: Establishing Maximum Allowable Operating Pressure or Maximum Operating Pressure Using Record Evidence, and... facilities of their responsibilities, under Federal integrity management (IM) regulations, to perform... system, especially when calculating Maximum Allowable Operating Pressure (MAOP) or Maximum Operating...
单业华; 李三忠; 许淑梅
2001-01-01
The information on bulk strain is recorded by the final distribution in azimuth of nonisometric minerals or mineral aggregates in tectonites. With the increase of strain in rocks, they became more evidently aligned to the direction of the maximum principal strain axis. However, besides the bulk strain, the final distribution in azimuth of particles are dependent upon the distribution prior to the strain in azimuth of particles, difference in viscosity between the particles and the matrix, the deformation within the particles, strain path, temporal relationship between the growth of minerals and the bulk strain, etc. All these factors are likely to produce an extremely complicated or even indeterminable relationship between the final distribution in azimuth of particles and the bulk strain in rocks. Under some assumptions, the authors have established a simple quantitative model of orientations of passive strain markers which is deterministically associated with the bulk strain in rocks. We use the modern technique of anneal modeling to estimate the bulk strain from observed orientations of passive strain markers. It is robust and has a wide application, especially in the general cases where no or few strain markers are available to other methods for strain analysis. It can make a better estimation of bulk strain in rocks since each observation is equally weighted in calculation. In order to validate our method, artificial orientation data of passive strain markers were generated by Monte Carlo sampling under some given bulk strains, which then were used to estimate the bulk strains in our method. As we expected, the accuracy of estimated bulk strains tends to increase with the number of observations, and seems to increase or reach a relatively stable state when the number is no less than ca. 160. This implies that at least 160 observations should be required for an accurate estimation of the bulk strain in rocks. When the number of observations is
Time series analysis by the Maximum Entropy method
Kirk, B.L.; Rust, B.W.; Van Winkle, W.
1979-01-01
The principal subject of this report is the use of the Maximum Entropy method for spectral analysis of time series. The classical Fourier method is also discussed, mainly as a standard for comparison with the Maximum Entropy method. Examples are given which clearly demonstrate the superiority of the latter method over the former when the time series is short. The report also includes a chapter outlining the theory of the method, a discussion of the effects of noise in the data, a chapter on significance tests, a discussion of the problem of choosing the prediction filter length, and, most importantly, a description of a package of FORTRAN subroutines for making the various calculations. Cross-referenced program listings are given in the appendices. The report also includes a chapter demonstrating the use of the programs by means of an example. Real time series like the lynx data and sunspot numbers are also analyzed. 22 figures, 21 tables, 53 references.
The Sherpa Maximum Likelihood Estimator
Nguyen, D.; Doe, S.; Evans, I.; Hain, R.; Primini, F.
2011-07-01
A primary goal for the second release of the Chandra Source Catalog (CSC) is to include X-ray sources with as few as 5 photon counts detected in stacked observations of the same field, while maintaining acceptable detection efficiency and false source rates. Aggressive source detection methods will result in detection of many false positive source candidates. Candidate detections will then be sent to a new tool, the Maximum Likelihood Estimator (MLE), to evaluate the likelihood that a detection is a real source. MLE uses the Sherpa modeling and fitting engine to fit a model of a background and source to multiple overlapping candidate source regions. A background model is calculated by simultaneously fitting the observed photon flux in multiple background regions. This model is used to determine the quality of the fit statistic for a background-only hypothesis in the potential source region. The statistic for a background-plus-source hypothesis is calculated by adding a Gaussian source model convolved with the appropriate Chandra point spread function (PSF) and simultaneously fitting the observed photon flux in each observation in the stack. Since a candidate source may be located anywhere in the field of view of each stacked observation, a different PSF must be used for each observation because of the strong spatial dependence of the Chandra PSF. The likelihood of a valid source being detected is a function of the two statistics (for background alone, and for background-plus-source). The MLE tool is an extensible Python module with potential for use by the general Chandra user.
Vestige: Maximum likelihood phylogenetic footprinting
Maxwell Peter
2005-05-01
Full Text Available Abstract Background Phylogenetic footprinting is the identification of functional regions of DNA by their evolutionary conservation. This is achieved by comparing orthologous regions from multiple species and identifying the DNA regions that have diverged less than neutral DNA. Vestige is a phylogenetic footprinting package built on the PyEvolve toolkit that uses probabilistic molecular evolutionary modelling to represent aspects of sequence evolution, including the conventional divergence measure employed by other footprinting approaches. In addition to measuring the divergence, Vestige allows the expansion of the definition of a phylogenetic footprint to include variation in the distribution of any molecular evolutionary processes. This is achieved by displaying the distribution of model parameters that represent partitions of molecular evolutionary substitutions. Examination of the spatial incidence of these effects across regions of the genome can identify DNA segments that differ in the nature of the evolutionary process. Results Vestige was applied to a reference dataset of the SCL locus from four species and provided clear identification of the known conserved regions in this dataset. To demonstrate the flexibility to use diverse models of molecular evolution and dissect the nature of the evolutionary process Vestige was used to footprint the Ka/Ks ratio in primate BRCA1 with a codon model of evolution. Two regions of putative adaptive evolution were identified illustrating the ability of Vestige to represent the spatial distribution of distinct molecular evolutionary processes. Conclusion Vestige provides a flexible, open platform for phylogenetic footprinting. Underpinned by the PyEvolve toolkit, Vestige provides a framework for visualising the signatures of evolutionary processes across the genome of numerous organisms simultaneously. By exploiting the maximum-likelihood statistical framework, the complex interplay between mutational
The Rookie's Playbook: Insights and Dirt for New Principals.
Tooms, Autumn
2003-01-01
Principal shares lessons and insights with beginning principals. Discusses differences between principals and assistant principals, staff relationships, competition for resources, giving and receiving loyalty, identifying and following a moral compass. (PKP)
EVALUATION OF LOCAL STRAIN EVOLUTION FROM METALLIC WHISKER FORMATION
Hoffman, E.; Lam, P.
2011-05-11
Evolution of local strain on electrodeposited tin films upon aging has been monitored by digital image correlation (DIC) for the first time. Maps of principal strains adjacent to whisker locations were constructed via comparing pre- and post-growth scanning electron microscopy (SEM) images. Results showed that the magnitude of the strain gradient plays an important role in whisker growth. DIC visualized the dynamic growth process in which the alteration of strain field has been identified to cause growth of subsequent whiskers.
Grissom, Jason A.; Loeb, Susanna; Mitani, Hajime
2015-01-01
Purpose: Time demands faced by school principals make principals' work increasingly difficult. Research outside education suggests that effective time management skills may help principals meet job demands, reduce job stress, and improve their performance. The purpose of this paper is to investigate these hypotheses. Design/methodology/approach:…
What Is a "Good" Principal? Perspectives of Aspiring Principals in Singapore
Ng, Pak Tee
2016-01-01
This paper presents the findings of an exploratory research project that examines what aspiring principals in Singapore think a good principal is, based on a framework of personal, interpersonal, and organizational dimensions of school leadership. According to the findings, a good principal has a moral purpose centered on personal values, a humble…
Principal Self-Efficacy and Work Engagement: Assessing a Norwegian Principal Self-Efficacy Scale
Federici, Roger A.; Skaalvik, Einar M.
2011-01-01
One purpose of the present study was to develop and test the factor structure of a multidimensional and hierarchical Norwegian Principal Self-Efficacy Scale (NPSES). Another purpose of the study was to investigate the relationship between principal self-efficacy and work engagement. Principal self-efficacy was measured by the 22-item NPSES. Work…
Principals and Blogs: In What Ways Does Blogging Support the Practices of School Principals?
Engebritson, Reggie Marie
2011-01-01
This study paper explores the factors that motivate school principals to blog and the effectiveness of those blogs in terms of instructional and technology leadership. Participants were school principals who blog and were sent a web-based survey. Fifty responded. Results indicate that principals blog to communicate to others, including parents,…
Grissom, Jason A.; Loeb, Susanna; Mitani, Hajime
2015-01-01
Purpose: Time demands faced by school principals make principals' work increasingly difficult. Research outside education suggests that effective time management skills may help principals meet job demands, reduce job stress, and improve their performance. The purpose of this paper is to investigate these hypotheses. Design/methodology/approach:…
Growth of group II Clostridium botulinum strains at extreme temperatures.
Derman, Yağmur; Lindström, Miia; Selby, Katja; Korkeala, Hannu
2011-11-01
The minimum and maximum growth temperatures and the maximum growth rates at 10, 30, 37, and 40°C were determined for 24 group II Clostridium botulinum strains. Genetic diversity of the strains was revealed by amplified fragment length polymorphism (AFLP) analysis. The minimum growth temperatures ranged from 6.2 to 8.6°C, and the maximum growth temperatures ranged from 34.7 to 39.9°C. The mean maximum growth temperatures and mean maximum growth rates of type E strains at 37°C were significantly higher than those of type B and type F strains. A significant correlation between maximum growth rates at 37°C and maximum growth temperatures was found for all strains. Some type E strains with a high minimum growth temperature also had a higher maximum growth rate at 37°C than at 30°C, which suggests that some group II C. botulinum strains are more mesophilic in their growth properties than others. We found relatively small differences between AFLP clusters, indicating that diverse genetic background among the strains was not reflected in the growth properties. The growth characteristics of group II C. botulinum and some type E strains with mesophilic growth properties may have an impact on inoculation studies and predictive modeling for assessing the safety of foods.
Garrett, W E
1996-01-01
with respect to the beneficial effects of warm-up, temperature, and stretching on the mechanical properties of muscle. These benefits potentially reduce the risks of strain injury to the muscle. Fortunately, many of the factors protecting muscle, such as strength, endurance, and flexibility, are also essential for maximum performance. Future studies should delineate the repair and recovery process emphasizing not only the recovery of function, but also the susceptibility to reinjury during the recovery phase.
Abdelahhad Barbour; Koshy Philip
2014-01-01
BACKGROUND: Salivaricins are bacteriocins produced by Streptococcus salivarius, some strains of which can have significant probiotic effects. S. salivarius strains were isolated from Malaysian subjects showing variable antimicrobial activity, metabolic profile, antibiotic susceptibility and lantibiotic production. METHODOLOGY/PRINCIPAL FINDINGS: In this study we report new S. salivarius strains isolated from Malaysian subjects with potential as probiotics. Safety assessment of these strains i...
Families in Crisis: What Principals Say.
National Elementary Principal, 1979
1979-01-01
Of principals responding to a survey, 95 percent agreed that children show behavioral and academic problems when their parents are undergoing separation or divorce. Offered are specific suggestions to help one-parent families adjust. (Author/LD)
Principal Hawaiian Islands Geoid Heights (GEOID96)
National Oceanic and Atmospheric Administration, Department of Commerce — This 2' geoid height grid for the Principal Hawaiian Islands is distributed as a GEOID96 model. The computation used 61,000 terrestrial and marine gravity data held...
A Comparative Study of Principals' Administrative Behaviour.
Chung, Kyung Ae
1989-01-01
Compared are the managerial behaviors and beliefs of Korean and American secondary school principals. Generalizations are proposed in the areas of work hours, work pace, communication skills, organizational style, instructional leadership, and other managerial behaviors. (16 references) (SI)
Principal Leader Behaviour and Shared Decision Making.
Moyle, Colin R. J.
1979-01-01
The leadership of the principal is a crucial factor in the functioning of the Instructional Improvement Committees (IICs) in the multiunit schools studies. IICs are representative cabinet-type leadership committees. (Author/IRT)
Noncommutative principal bundles through twist deformation
Aschieri, Paolo; Pagani, Chiara; Schenkel, Alexander
2016-01-01
We construct noncommutative principal bundles deforming principal bundles with a Drinfeld twist (2-cocycle). If the twist is associated with the structure group then we have a deformation of the fibers. If the twist is associated with the automorphism group of the principal bundle, then we obtain noncommutative deformations of the base space as well. Combining the two twist deformations we obtain noncommutative principal bundles with both noncommutative fibers and base space. More in general, the natural isomorphisms proving the equivalence of a closed monoidal category of modules and its twist related one are used to obtain new Hopf-Galois extensions as twists of Hopf-Galois extensions. A sheaf approach is also considered, and examples presented.
Check List: Are You a Gifted Principal?
Taylor, Vicki L.
1984-01-01
An 18-item check list is provided for principals to evaluate themselves relative to encouraging gifts and talents of their most able students. Suggestions are given in the areas of educational needs, specialized materials, and counseling. (MC)
Paranoia: Perceptions of Public School Principals.
Salmon, Daniel A.
1980-01-01
Examines forces which are undermining the principal's leadership role and ability to effectively administer the school: teachers and unions; the competency movement; political and community interest groups; and media pundits. (SJL)
General frame structures on quantum principal bundles
Durdevic, M
1996-01-01
A noncommutative-geometric generalization of the classical formalism of frame bundles is developed, incorporating into the theory of quantum principal bundles the concept of the Levi-Civita connection. The construction of a natural differential calculus on quantum principal frame bundles is presented, including the construction of the associated differential calculus on the structure group. General torsion operators are defined and analyzed. Illustrative examples are presented.
A Geometric Approach to Noncommutative Principal Bundles
Wagner, Stefan
2011-01-01
From a geometrical point of view it is, so far, not sufficiently well understood what should be a "noncommutative principal bundle". Still, there is a well-developed abstract algebraic approach using the theory of Hopf algebras. An important handicap of this approach is the ignorance of topological and geometrical aspects. The aim of this thesis is to develop a geometrically oriented approach to the noncommutative geometry of principal bundles based on dynamical systems and the representation theory of the corresponding transformation group.
Immorally obtained principal increases investors’ risk preference
Chen, Jiaxin; He, Guibing
2017-01-01
Capital derived from immoral sources is increasingly circulated in today’s financial markets. The moral associations of capital are important, although their impact on investment remains unknown. This research aims to explore the influence of principal source morality on investors’ risk preferences. Three studies were conducted in this regard. Study 1 finds that investors are more risk-seeking when their principal is earned immorally (through lying), whereas their risk preferences do not change when they invest money earned from neutral sources after engaging in immoral behavior. Study 2 reveals that guilt fully mediates the relationship between principal source morality and investors’ risk preferences. Studies 3a and 3b introduce a new immoral principal source and a new manipulation method to improve external validity. Guilt is shown to the decrease the subjective value of morally flawed principal, leading to higher risk preference. The findings show the influence of morality-related features of principal on people’s investment behavior and further support mental account theory. The results also predict the potential threats of “grey principal” to market stability. PMID:28369117
Nutrition education for adolescents: principals' views.
Lai-Yeung, Wai-Ling Theresa
2011-01-01
This study aimed to examine school principals' perceptions of the school environment in Hong Kong as a context for the dissemination of food knowledge and inculcation of healthy eating habits. A questionnaire survey was administered in secondary schools in Hong Kong to survey Principals' views of students' food choices, operation of the school tuck shop, and promotion of healthy eating at school. Questionnaires were disseminated to all the secondary schools offering Home Economics (300 out of 466), and 188 schools responded, making up a response rate of 63%. Collected data were analyzed using SPSS. Most of the schools (82%) claimed to have a food policy to monitor the operation of the school canteen, and about half (52%) asserted there were insufficient resources to promote healthy eating at school. Principals (88%) generally considered it not acceptable for the school tuck shop to sell junk food; however, 45% thought that banning junk food at school would not help students develop good eating habits. Only 4% of the principals believed nutrition education influenced eating habits; whereas the majority (94%) felt that even with acquisition of food knowledge, students may not be able to put theory into practice. Cooking skills were considered important but principals (92%) considered transmission of cooking skills the responsibility of the students' families. Most of the principals (94%) believed that school-family collaboration is important in promoting healthy eating. Further efforts should be made to enhance the effectiveness of school food policies and to construct healthy school environments in secondary schools.
Heyland, Mark; Trepczynski, Adam; Duda, Georg N; Zehn, Manfred; Schaser, Klaus-Dieter; Märdian, Sven
2015-12-01
Selection of boundary constraints may influence amount and distribution of loads. The purpose of this study is to analyze the potential of inertia relief and follower load to maintain the effects of musculoskeletal loads even under large deflections in patient specific finite element models of intact or fractured bone compared to empiric boundary constraints which have been shown to lead to physiological displacements and surface strains. The goal is to elucidate the use of boundary conditions in strain analyses of bones. Finite element models of the intact femur and a model of clinically relevant fracture stabilization by locking plate fixation were analyzed with normal walking loading conditions for different boundary conditions, specifically re-balanced loading, inertia relief and follower load. Peak principal cortex surface strains for different boundary conditions are consistent (maximum deviation 13.7%) except for inertia relief without force balancing (maximum deviation 108.4%). Influence of follower load on displacements increases with higher deflection in fracture model (from 3% to 7% for force balanced model). For load balanced models, follower load had only minor influence, though the effect increases strongly with higher deflection. Conventional constraints of fixed nodes in space should be carefully reconsidered because their type and position are challenging to justify and for their potential to introduce relevant non-physiological reaction forces. Inertia relief provides an alternative method which yields physiological strain results.
Receiver function estimated by maximum entropy deconvolution
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.
13 CFR 107.845 - Maximum rate of amortization on Loans and Debt Securities.
2010-01-01
... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Maximum rate of amortization on... ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES Financing of Small Businesses by Licensees Structuring... rate of amortization on Loans and Debt Securities. The principal of any Loan (or the loan portion...
Foch, Eric; Milner, Clare E
2014-01-03
Iliotibial band syndrome (ITBS) is a common knee overuse injury among female runners. Atypical discrete trunk and lower extremity biomechanics during running may be associated with the etiology of ITBS. Examining discrete data points limits the interpretation of a waveform to a single value. Characterizing entire kinematic and kinetic waveforms may provide additional insight into biomechanical factors associated with ITBS. Therefore, the purpose of this cross-sectional investigation was to determine whether female runners with previous ITBS exhibited differences in kinematics and kinetics compared to controls using a principal components analysis (PCA) approach. Forty participants comprised two groups: previous ITBS and controls. Principal component scores were retained for the first three principal components and were analyzed using independent t-tests. The retained principal components accounted for 93-99% of the total variance within each waveform. Runners with previous ITBS exhibited low principal component one scores for frontal plane hip angle. Principal component one accounted for the overall magnitude in hip adduction which indicated that runners with previous ITBS assumed less hip adduction throughout stance. No differences in the remaining retained principal component scores for the waveforms were detected among groups. A smaller hip adduction angle throughout the stance phase of running may be a compensatory strategy to limit iliotibial band strain. This running strategy may have persisted after ITBS symptoms subsided.
Maximum Power from a Solar Panel
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.
Application of the maximum entropy method to profile analysis
Armstrong, N.; Kalceff, W. [University of Technology, Department of Applied Physics, Sydney, NSW (Australia); Cline, J.P. [National Institute of Standards and Technology, Gaithersburg, (United States)
1999-12-01
Full text: A maximum entropy (MaxEnt) method for analysing crystallite size- and strain-induced x-ray profile broadening is presented. This method treats the problems of determining the specimen profile, crystallite size distribution, and strain distribution in a general way by considering them as inverse problems. A common difficulty faced by many experimenters is their inability to determine a well-conditioned solution of the integral equation, which preserves the positivity of the profile or distribution. We show that the MaxEnt method overcomes this problem, while also enabling a priori information, in the form of a model, to be introduced into it. Additionally, we demonstrate that the method is fully quantitative, in that uncertainties in the solution profile or solution distribution can be determined and used in subsequent calculations, including mean particle sizes and rms strain. An outline of the MaxEnt method is presented for the specific problems of determining the specimen profile and crystallite or strain distributions for the correspondingly broadened profiles. This approach offers an alternative to standard methods such as those of Williamson-Hall and Warren-Averbach. An application of the MaxEnt method is demonstrated in the analysis of alumina size-broadened diffraction data (from NIST, Gaithersburg). It is used to determine the specimen profile and column-length distribution of the scattering domains. Finally, these results are compared with the corresponding Williamson-Hall and Warren-Averbach analyses. Copyright (1999) Australian X-ray Analytical Association Inc.
Choreographies with Secure Boxes and Compromised Principals
Carbone, Marco; 10.4204/EPTCS.12.1
2009-01-01
We equip choreography-level session descriptions with a simple abstraction of a security infrastructure. Message components may be enclosed within (possibly nested) "boxes" annotated with the intended source and destination of those components. The boxes are to be implemented with cryptography. Strand spaces provide a semantics for these choreographies, in which some roles may be played by compromised principals. A skeleton is a partially ordered structure containing local behaviors (strands) executed by regular (non-compromised) principals. A skeleton is realized if it contains enough regular strands so that it could actually occur, in combination with any possible activity of compromised principals. It is delivery guaranteed (DG) realized if, in addition, every message transmitted to a regular participant is also delivered. We define a novel transition system on skeletons, in which the steps add regular strands. These steps solve tests, i.e. parts of the skeleton that could not occur without additional regu...
Principal component regression for crop yield estimation
Suryanarayana, T M V
2016-01-01
This book highlights the estimation of crop yield in Central Gujarat, especially with regard to the development of Multiple Regression Models and Principal Component Regression (PCR) models using climatological parameters as independent variables and crop yield as a dependent variable. It subsequently compares the multiple linear regression (MLR) and PCR results, and discusses the significance of PCR for crop yield estimation. In this context, the book also covers Principal Component Analysis (PCA), a statistical procedure used to reduce a number of correlated variables into a smaller number of uncorrelated variables called principal components (PC). This book will be helpful to the students and researchers, starting their works on climate and agriculture, mainly focussing on estimation models. The flow of chapters takes the readers in a smooth path, in understanding climate and weather and impact of climate change, and gradually proceeds towards downscaling techniques and then finally towards development of ...
... flexor - aftercare; Hip flexor injury - aftercare; Hip flexor tear - aftercare; Iliopsoas strain - aftercare; Strained iliopsoas muscle - aftercare; Torn iliopsoas muscle - aftercare; Psoas strain - aftercare
Direct Numerical Simulation of Combustion Using Principal Component Analysis
Owoyele, Opeoluwa; Echekki, Tarek
2016-11-01
We investigate the potential of accelerating chemistry integration during the direct numerical simulation (DNS) of complex fuels based on the transport equations of representative scalars that span the desired composition space using principal component analysis (PCA). The transported principal components (PCs) offer significant potential to reduce the computational cost of DNS through a reduction in the number of transported scalars, as well as the spatial and temporal resolution requirements. The strategy is demonstrated using DNS of a premixed methane-air flame in a 2D vortical flow and is extended to the 3D geometry to further demonstrate the computational efficiency of PC transport. The PCs are derived from a priori PCA of a subset of the full thermo-chemical scalars' vector. The PCs' chemical source terms and transport properties are constructed and tabulated in terms of the PCs using artificial neural networks (ANN). Comparison of DNS based on a full thermo-chemical state and DNS based on PC transport based on 6 PCs shows excellent agreement even for species that are not included in the PCA reduction. The transported PCs reproduce some of the salient features of strongly curved and strongly strained flames. The 2D DNS results also show a significant reduction of two orders of magnitude in the computational cost of the simulations, which enables an extension of the PCA approach to 3D DNS under similar computational requirements. This work was supported by the National Science Foundation Grant DMS-1217200.
Outlier Mining Based on Principal Component Estimation
Hu Yang; Ting Yang
2005-01-01
Outlier mining is an important aspect in data mining and the outlier mining based on Cook distance is most commonly used. But we know that when the data have multicollinearity, the traditional Cook method is no longer effective. Considering the excellence of the principal component estimation, we use it to substitute the least squares estimation, and then give the Cook distance measurement based on principal component estimation, which can be used in outlier mining. At the same time, we have done some research on related theories and application problems.
Principal Component Analysis in ECG Signal Processing
Andreas Bollmann
2007-01-01
Full Text Available This paper reviews the current status of principal component analysis in the area of ECG signal processing. The fundamentals of PCA are briefly described and the relationship between PCA and Karhunen-Loève transform is explained. Aspects on PCA related to data with temporal and spatial correlations are considered as adaptive estimation of principal components is. Several ECG applications are reviewed where PCA techniques have been successfully employed, including data compression, ST-T segment analysis for the detection of myocardial ischemia and abnormalities in ventricular repolarization, extraction of atrial fibrillatory waves for detailed characterization of atrial fibrillation, and analysis of body surface potential maps.
The inverse maximum dynamic flow problem
BAGHERIAN; Mehri
2010-01-01
We consider the inverse maximum dynamic flow (IMDF) problem.IMDF problem can be described as: how to change the capacity vector of a dynamic network as little as possible so that a given feasible dynamic flow becomes a maximum dynamic flow.After discussing some characteristics of this problem,it is converted to a constrained minimum dynamic cut problem.Then an efficient algorithm which uses two maximum dynamic flow algorithms is proposed to solve the problem.
MO-C-17A-08: Evaluation of Lung Deformation Using Three Dimensional Strain Maps
Cui, T [Duke University, Durham, NC (United States); Huang, Q [Duke Unversity, Durham, NC (United States); Miller, W [University of Virginia, Charlottesville, VA (United States); Zhong, X [Siemens Healthcare, Atlanta, GA (United States); Yin, F; Cai, J [Duke University Medical Center, Durham, NC (United States)
2014-06-15
Purpose: To develop a systematic approach to generate three dimensional (3D) strain maps of lung using the displacement vector field (DVF) during the respiratory deformation, and to demonstrate its application in evaluating deformable image registration (DIR). Methods: A DVF based strain tensor at each voxel of interest (VOI) was calculated from the relative displacements between the VOI and each of the six nearest neighbors. The maximum and minimum stretches of a VOI can be determined by the principal strains (E{sub 1}, E{sub 2} and E{sub 3}), which are the eigenvalues and the corresponding strain tensors. Two healthy volunteers enrolled in this study under IRB-approved protocol, each was scanned using 3D Hyperpolarized He-3 tagging-MRI and 3D proton-MRI with TrueFISP sequence at the endof- inhalation (EOI) and the end-of-exhalation (EOE) phases. 3D DVFs of tagging- and proton-MRI were obtained by the direct measurements of the tagging grid trajectory and by the DIR method implemented in commercial software. Results: 3D strain maps were successfully generated for all DVFs. The principal strain E1s were calculated as 0.43±0.05 and 0.17±0.25 for tagging-MRI and proton-MRI, respectively. The large values of E{sub 1} indicate the predominant lung motion in the superior-inferior (SI) direction. Given that the DVFs from the tagging images are considered as the ground truth, the discrepancies in the DIR-based strain maps suggest the inaccuracy of the DIR algorithm. In the E{sub 1} maps of tagging-MRI for subject 1, the fissures were distinguishable by the larger values (0.49±0.02) from the adjacent tissues (0.41±0.03) due to the larger relative displacement between the lung lobes. Conclusion: We have successfully developed a methodology to generate DVF-based 3D strain maps of lung. It can potentially enable us to better understand the pulmonary biomechanics and to evaluate and improve the DIR algorithms for the lung deformation. We are currently studying more
Maximum permissible voltage of YBCO coated conductors
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.
Quality Aware Compression of Electrocardiogram Using Principal Component Analysis.
Gupta, Rajarshi
2016-05-01
Electrocardiogram (ECG) compression finds wide application in various patient monitoring purposes. Quality control in ECG compression ensures reconstruction quality and its clinical acceptance for diagnostic decision making. In this paper, a quality aware compression method of single lead ECG is described using principal component analysis (PCA). After pre-processing, beat extraction and PCA decomposition, two independent quality criteria, namely, bit rate control (BRC) or error control (EC) criteria were set to select optimal principal components, eigenvectors and their quantization level to achieve desired bit rate or error measure. The selected principal components and eigenvectors were finally compressed using a modified delta and Huffman encoder. The algorithms were validated with 32 sets of MIT Arrhythmia data and 60 normal and 30 sets of diagnostic ECG data from PTB Diagnostic ECG data ptbdb, all at 1 kHz sampling. For BRC with a CR threshold of 40, an average Compression Ratio (CR), percentage root mean squared difference normalized (PRDN) and maximum absolute error (MAE) of 50.74, 16.22 and 0.243 mV respectively were obtained. For EC with an upper limit of 5 % PRDN and 0.1 mV MAE, the average CR, PRDN and MAE of 9.48, 4.13 and 0.049 mV respectively were obtained. For mitdb data 117, the reconstruction quality could be preserved up to CR of 68.96 by extending the BRC threshold. The proposed method yields better results than recently published works on quality controlled ECG compression.
The Principals' Center Movement: When School Leaders Become Learners.
Levine, Sarah L.
1986-01-01
This article describes principals' centers and the principals' center movement, identifying key issues raised by them. Future directions and persistent questions for the principals' center movement are developed. (MT)
Haller, Alicia; Hunt, Erika
2016-01-01
Research has demonstrated that principals have a powerful impact on school improvement and student learning. Principals play a vital role in recruiting, developing, and retaining effective teachers; creating a school-wide culture of learning; and implementing a continuous improvement plan aimed at increasing student achievement. Leithwood, Louis,…
Knuth, Richard K.
2004-01-01
Probably no effort has been more successful than the Interstate School Leaders Licensure Consortium (ISLLC) in capturing the current complexity of the principal's role and in providing direction for the professional development and selection of principals. As more states require universities to restructure training programs to align with the ISLLC…
Principal Self-Efficacy, Teacher Perceptions of Principal Performance, and Teacher Job Satisfaction
Evans, Molly Lynn
2016-01-01
In public schools, the principal's role is of paramount importance in influencing teachers to excel and to keep their job satisfaction high. The self-efficacy of leaders is an important characteristic of leadership, but this issue has not been extensively explored in school principals. Using internet-based questionnaires, this study obtained…
Talbot, Danny; Crow, Gary M.
Researchers who have focused on issues of interpersonal communication in organizations have concluded that it is an essential component of organizational life. This paper presents findings of a study that examined the role conceptions of principals in the Centenial Schools Program (CSP) and those of principals in non-CSP schools. Communicator…
Great Principals at Scale: Creating District Conditions That Enable All Principals to Be Effective
Ikemoto, Gina; Taliaferro, Lori; Fenton, Benjamin; Davis, Jacquelyn
2014-01-01
School leaders are critical in the lives of students and to the development of their teachers. Unfortunately, in too many instances, principals are effective in spite of--rather than because of--district conditions. To truly improve student achievement for all students across the country, well-prepared principals need the tools, support, and…
Principal Self-Efficacy, Teacher Perceptions of Principal Performance, and Teacher Job Satisfaction
Evans, Molly Lynn
2016-01-01
In public schools, the principal's role is of paramount importance in influencing teachers to excel and to keep their job satisfaction high. The self-efficacy of leaders is an important characteristic of leadership, but this issue has not been extensively explored in school principals. Using internet-based questionnaires, this study obtained…
Keith Walker
2003-09-01
Full Text Available This paper reports the findings related to the International Beginning Principals study, which examined factors perceived by first year principals to both complicate, and account for, first year principalship successes in rural jurisdictions. Specifically, for this paper we deal with factors seen as significant in establishing oneself as a first time principal in a rural Canadian school. The general findings from this study centred on training and experience related to administration of schools. Many first time principals in rural schools had limited specific preparation for the principalship, or other related administrative roles such as the vice principalship. Such findings have taken on more importance in the last several years as school districts find it increasingly difficult to recruit principals for smaller rural schools.
Sex Education: The Principle and the Principal.
Wayne, Joseph E.
1981-01-01
The school principal is in a propitious position to offer leadership in developing a sex education program. His position of leadership and respect can facilitate the development of a Citizens Advisory Committee which, in turn, can ensure cooperation and leadership in setting the goals for developing a sex education program. (Author/CM)
Transformational Leadership Behaviors in Elementary School Principals
Ergle, Barbara
2012-01-01
School leaders face high expectations from society for leadership effectiveness. While it is commonly accepted that leadership practices contribute to school excellence, specific behaviors of effective elementary principals in the local context were not well understood. The purpose of this mixed methods study was to investigate self-reported…
Quantum principal bundles and corresponding gauge theories
Durdevic, M
1995-01-01
A generalization of classical gauge theory is presented, in the framework of a noncommutative-geometric formalism of quantum principal bundles over smooth manifolds. Quantum counterparts of classical gauge bundles, and classical gauge transformations, are introduced and investigated. A natural differential calculus on quantum gauge bundles is constructed and analyzed. Kinematical and dynamical properties of corresponding gauge theories are discussed.
Principals and the Power of Recommending Students
无
2009-01-01
Attending one of China’s most prestigious institutions of higher learning, Peking University (PKU), is a dream for the vast majority of China’s middle school graduates. On November 16, the university released a list of 39 senior middle schools across the country whose principals have been
Principals in Partnership with Math Coaches
Grant, Catherine Miles; Davenport, Linda Ruiz
2009-01-01
One of the most promising developments in math education is the fact that many districts are hiring math coaches--also called math resource teachers, math facilitators, math lead teachers, or math specialists--to assist elementary-level teachers with math instruction. What must not be lost, however, is that principals play an essential role in…
Principals' Transformational Leadership in School Improvement
Yang, Yingxiu
2013-01-01
Purpose: This paper aims to contribute experience and ideas of the transformational leadership, not only for the principal want to improve leadership himself (herself), but also for the school at critical period of improvement, through summarizing forming process and the problem during the course and key factors that affect the course.…
The Relationship between Principals' Managerial Approaches and ...
Nekky Umera
Cell phone - +254 724 249 730; Office - +254 065 32369 ... Ultimately, student discipline may be affected. This paper focuses on findings of a study to establish the ... behaviour is an essential variable in enhancing school outcomes (Nasibi, .... Three questionnaires were used to collect data from principals, teachers and.
Principal component analysis implementation in Java
Wójtowicz, Sebastian; Belka, Radosław; Sławiński, Tomasz; Parian, Mahnaz
2015-09-01
In this paper we show how PCA (Principal Component Analysis) method can be implemented using Java programming language. We consider using PCA algorithm especially in analysed data obtained from Raman spectroscopy measurements, but other applications of developed software should also be possible. Our goal is to create a general purpose PCA application, ready to run on every platform which is supported by Java.
Principals' Leadership Styles and Student Achievement
Harnish, David Alan
2012-01-01
Many schools struggle to meet No Child Left Behind's stringent adequate yearly progress standards, although the benchmark has stimulated national creativity and reform. The purpose of this study was to explore teacher perceptions of principals' leadership styles, curriculum reform, and student achievement to ascertain possible factors to improve…
What Principals Should Know About Food Allergies.
Munoz-Furlong, Anne
2002-01-01
Describes what principals should know about recent research findings on food allergies (peanuts, tree nuts, milk, eggs, soy, wheat) that can produce severe or life-threatening reactions in children. Asserts that every school should have trained staff and written procedures for reacting quickly to allergic reactions. (PKP)
Teachers' Perceptions Regarding School Principals' Coaching Skills
Yirci, Ramazan; Özdemir, Tuncay Yavuz; Kartal, Seçil Eda; Kocabas, Ibrahim
2014-01-01
The purpose of this study was to find out teachers' perceptions about school principals' coaching skills. The study was carried out within qualitative research methods. The study group included 76 teachers in Elazig and 73 teachers in Kahramanmaras provinces of Turkey. All the data were processed using Nvivo 9 software. The results indicate that…
Principal Bundles on the Projective Line
V B Mehta; S Subramanian
2002-08-01
We classify principal -bundles on the projective line over an arbitrary field of characteristic ≠ 2 or 3, where is a reductive group. If such a bundle is trivial at a -rational point, then the structure group can be reduced to a maximal torus.
Managerial Leadership and the Effective Principal.
Yukl, Gary
To help relate management ideas and knowledge to educational administration, the author reviews the major theories and findings from the last 20 years on managerial leadership and discusses their relevance for school principals. He first summarizes findings from three approaches: the traits approach, emphasizing managerial motivation and skills;…
Principal Connection / Amazon and the Whole Teacher
Hoerr, Thomas R.
2015-01-01
A recent controversy over Amazon's culture has strong implications for the whole child approach, and it offers powerful lessons for principals. A significant difference between the culture of so many businesses today and the culture at good schools is that in good schools, the welfare of the employees is very important. Student success is the…
Conceptualizing Social Justice: Interviews with Principals
Wang, Fei
2015-01-01
Purpose: Today, as the understanding of diversity is further expanded, the meaning of social justice becomes even more complicated, if not confusing. The purpose of this paper is to explore how school principals with social justice commitment understand and perceive social justice in their leadership practices. Design/methodology/approach: A…
Principal component analysis of phenolic acid spectra
Phenolic acids are common plant metabolites that exhibit bioactive properties and have applications in functional food and animal feed formulations. The ultraviolet (UV) and infrared (IR) spectra of four closely related phenolic acid structures were evaluated by principal component analysis (PCA) to...
Principal component analysis of psoriasis lesions images
Maletti, Gabriela Mariel; Ersbøll, Bjarne Kjær
2003-01-01
A set of RGB images of psoriasis lesions is used. By visual examination of these images, there seem to be no common pattern that could be used to find and align the lesions within and between sessions. It is expected that the principal components of the original images could be useful during future...
An Exploration of Principal Instructional Technology Leadership
Townsend, LaTricia Walker
2013-01-01
Nationwide the demand for schools to incorporate technology into their educational programs is great. In response, North Carolina developed the IMPACT model in 2003 to provide a comprehensive model for technology integration in the state. The model is aligned to national educational technology standards for teachers, students, and principals.…
Principal component analysis of symmetric fuzzy data
Giordani, Paolo; Kiers, Henk A.L.
2004-01-01
Principal Component Analysis (PCA) is a well-known tool often used for the exploratory analysis of a numerical data set. Here an extension of classical PCA is proposed, which deals with fuzzy data (in short PCAF), where the elementary datum cannot be recognized exactly by a specific number but by a
The Role of Principals in Politics.
Yingling, Walter S.
This talk uses humor to draw attention to the principal's responsibility and potential in promoting adequate education legislation. Knowledge of the issues in current legislation, contact with legislators, and organized action by administrators' associations are among the topics commented on. (PGD)
The Principal Kids Love To Hug.
Collins, Patrick
2000-01-01
David Nufer, Alaska's National Distinguished Principal for 1999, uses collaboration to create a family atmosphere at Finger Lake (Alaska) Elementary School. He turned the scheduling process over to teachers, involved teachers and parents in implementing a two-track system of mixed and single-age classrooms, brought in senior citizens to supplement…
The Principal's Mind-Set for Data
Fox, Dennis
2013-01-01
Is there a school leader anywhere who hasn't been directed, or at least encouraged, to "analyze the data" and practice what has been termed "data-driven decision-making"? Today's principal is expected to be able to skillfully collect, organize, analyze, interpret and use a variety of data in order to improve instruction, services and programs for…
Principal normal indicatrices of closed space curves
Røgen, Peter
1999-01-01
A theorem due to J. Weiner, which is also proven by B. Solomon, implies that a principal normal indicatrix of a closed space curve with nonvanishing curvature has integrated geodesic curvature zero and contains no subarc with integrated geodesic curvature pi. We prove that the inverse problem alw...
Elementary Teachers' Perceptions of Elementary Principals' Effectiveness
Fridenvalds, Kriss R.
2012-01-01
This dissertation examined the beliefs of elementary teachers to determine if their perceptions of effective principal leadership align to transformational leadership theory vis-a-vis the Educational Leadership Policy Standards (ELPS). A phenomenological, single-case study approach was utilized by means of a mixed-methodological, Web-based survey,…
Autocrats, Bureaucrats, and Buffoons: Images of Principals.
Glanz, Jerry
1998-01-01
A content analysis of over 35 American motion pictures and television sitcoms since the 1950s showed principals most often portrayed as autocrats, bureaucrats, or buffoons. Sometimes, as in the TV movie "Kidz in the Woods," a single show depicts all three characteristics. Promoting instructional leadership and an ethic of caring among…
The Principal as Chief Executive Officer.
Dubin, Andrew E., Ed.
This book was predicated on the idea that an effective principal must be proactive in decision making and have available appropriate information sources to make good decisions. Each chapter analyzes decision making from the perspective of different professionals in education and business management. Through the use of personal accounts and case…
Burnout And Lifestyle Of Principals And Entrepreneurs
Jasna Lavrenčič
2014-12-01
Full Text Available Research Question (RQ: What kind of lifestyle do the principals and entrepreneurs lead? Does the lifestyle of principals and entrepreneurs influence burnout? Purpose: To find out, based on the results of a questionnaire, what kind of lifestyle both researched groups lead. Does lifestyle have an influence on the occurrence of the phenomenon of burnout. Method: We used the method of data collection by questionnaire. Acquired data were analyzed using SPSS, descriptive and inference statistics. Results: Results showed, that both groups lead a similar lifestyle and that lifestyle influences burnout with principals, as well as entrepreneurs. Organization: School principals and entrepreneurs are the heads of individual organizations or companies, the goal of which is success. To be successful in their work, they must adapt their lifestyle, which can be healthy or unhealthy. If their lifestyle is unhealthy, it can lead to burnout. Society: With results of the questionnaire we would like to answer the question about the lifestyle of both groups and its influence on the occurrence of burnout. Originality: The study of lifestyle and the occurrence of burnout in these two groups is the first study in this area. Limitations/Future Research: In continuation, research groups could be submitted to the research fields of effort physiology and tracking of certain haematological parameters, such as cholesterol, blood sugar and stress hormones - adrenaline, noradrenalin, cortisol. Thus, we could carry out an even more in depth research of the connection between lifestyle and burnout.
The Principal's Playbook: Tackling School Improvement
Protheroe, Nancy
2010-01-01
"The Principal's Playbook: Tackling School Improvement" brings together the best thinking on successful schools and classrooms to help school administrators engage their faculty in discussion about effective school improvement strategies. Designed to support both school improvement efforts and professional development, each chapter includes…
Real-Time Principal-Component Analysis
Duong, Vu; Duong, Tuan
2005-01-01
A recently written computer program implements dominant-element-based gradient descent and dynamic initial learning rate (DOGEDYN), which was described in Method of Real-Time Principal-Component Analysis (NPO-40034) NASA Tech Briefs, Vol. 29, No. 1 (January 2005), page 59. To recapitulate: DOGEDYN is a method of sequential principal-component analysis (PCA) suitable for such applications as data compression and extraction of features from sets of data. In DOGEDYN, input data are represented as a sequence of vectors acquired at sampling times. The learning algorithm in DOGEDYN involves sequential extraction of principal vectors by means of a gradient descent in which only the dominant element is used at each iteration. Each iteration includes updating of elements of a weight matrix by amounts proportional to a dynamic initial learning rate chosen to increase the rate of convergence by compensating for the energy lost through the previous extraction of principal components. In comparison with a prior method of gradient-descent-based sequential PCA, DOGEDYN involves less computation and offers a greater rate of learning convergence. The sequential DOGEDYN computations require less memory than would parallel computations for the same purpose. The DOGEDYN software can be executed on a personal computer.
Primary School Principals' Experiences with Smartphone Apps
Çakir, Rahman; Aktay, Sayim
2016-01-01
Smartphones are not just pieces of hardware, they at same time also dip into software features such as communication systems. The aim of this study is to examine primary school principals' experiences with smart phone applications. Shedding light on this subject means that this research is qualitative. Criterion sampling has been intentionally…
Probabilistic Principal Component Analysis for Metabolomic Data.
Nyamundanda, Gift
2010-11-23
Abstract Background Data from metabolomic studies are typically complex and high-dimensional. Principal component analysis (PCA) is currently the most widely used statistical technique for analyzing metabolomic data. However, PCA is limited by the fact that it is not based on a statistical model. Results Here, probabilistic principal component analysis (PPCA) which addresses some of the limitations of PCA, is reviewed and extended. A novel extension of PPCA, called probabilistic principal component and covariates analysis (PPCCA), is introduced which provides a flexible approach to jointly model metabolomic data and additional covariate information. The use of a mixture of PPCA models for discovering the number of inherent groups in metabolomic data is demonstrated. The jackknife technique is employed to construct confidence intervals for estimated model parameters throughout. The optimal number of principal components is determined through the use of the Bayesian Information Criterion model selection tool, which is modified to address the high dimensionality of the data. Conclusions The methods presented are illustrated through an application to metabolomic data sets. Jointly modeling metabolomic data and covariates was successfully achieved and has the potential to provide deeper insight to the underlying data structure. Examination of confidence intervals for the model parameters, such as loadings, allows for principled and clear interpretation of the underlying data structure. A software package called MetabolAnalyze, freely available through the R statistical software, has been developed to facilitate implementation of the presented methods in the metabolomics field.
Technology Leadership Conditions among Nebraska School Principals
Curnyn, Molly A.
2013-01-01
As visionary leaders, school administrators are responsible for leading their schools into the 21st century by integrating technology to enhance learning and teaching. As technology leaders, principals must apply rigorous thought into the overall role that technology plays in the enhancement of student learning. Leveraging technology will assist…
Principals in Partnership with Math Coaches
Grant, Catherine Miles; Davenport, Linda Ruiz
2009-01-01
One of the most promising developments in math education is the fact that many districts are hiring math coaches--also called math resource teachers, math facilitators, math lead teachers, or math specialists--to assist elementary-level teachers with math instruction. What must not be lost, however, is that principals play an essential role in…
California Testing: How Principals Choose Priorities.
Bushman, James; Goodman, Greg; Brown-Welty, Sharon; Dorn, Shelly
2001-01-01
The Central Valley (California) Educational Research Consortium asked 118 area principals what they were doing to improve their lowest achieving students' education. Respondents are focusing on individualizing instruction, aligning curricula to standards, advocating teaching to standards and tests, promoting new curriculum methodologies, and…
Stochastic convex sparse principal component analysis.
Baytas, Inci M; Lin, Kaixiang; Wang, Fei; Jain, Anil K; Zhou, Jiayu
2016-12-01
Principal component analysis (PCA) is a dimensionality reduction and data analysis tool commonly used in many areas. The main idea of PCA is to represent high-dimensional data with a few representative components that capture most of the variance present in the data. However, there is an obvious disadvantage of traditional PCA when it is applied to analyze data where interpretability is important. In applications, where the features have some physical meanings, we lose the ability to interpret the principal components extracted by conventional PCA because each principal component is a linear combination of all the original features. For this reason, sparse PCA has been proposed to improve the interpretability of traditional PCA by introducing sparsity to the loading vectors of principal components. The sparse PCA can be formulated as an ℓ1 regularized optimization problem, which can be solved by proximal gradient methods. However, these methods do not scale well because computation of the exact gradient is generally required at each iteration. Stochastic gradient framework addresses this challenge by computing an expected gradient at each iteration. Nevertheless, stochastic approaches typically have low convergence rates due to the high variance. In this paper, we propose a convex sparse principal component analysis (Cvx-SPCA), which leverages a proximal variance reduced stochastic scheme to achieve a geometric convergence rate. We further show that the convergence analysis can be significantly simplified by using a weak condition which allows a broader class of objectives to be applied. The efficiency and effectiveness of the proposed method are demonstrated on a large-scale electronic medical record cohort.
Generalised maximum entropy and heterogeneous technologies
Oude Lansink, A.G.J.M.
1999-01-01
Generalised maximum entropy methods are used to estimate a dual model of production on panel data of Dutch cash crop farms over the period 1970-1992. The generalised maximum entropy approach allows a coherent system of input demand and output supply equations to be estimated for each farm in the sam
20 CFR 229.48 - Family maximum.
2010-04-01
... month on one person's earnings record is limited. This limited amount is called the family maximum. The family maximum used to adjust the social security overall minimum rate is based on the employee's Overall..., when any of the persons entitled to benefits on the insured individual's compensation would, except...
The maximum rotation of a galactic disc
Bottema, R
1997-01-01
The observed stellar velocity dispersions of galactic discs show that the maximum rotation of a disc is on average 63% of the observed maximum rotation. This criterion can, however, not be applied to small or low surface brightness (LSB) galaxies because such systems show, in general, a continuously
Decomposition of spectra using maximum autocorrelation factors
Larsen, Rasmus
2001-01-01
into classification or regression type analyses. A featured method for low dimensional representation of multivariate datasets is Hotellings principal components transform. We will extend the use of principal components analysis incorporating new information into the algorithm. This new information consists......This paper addresses the problem of generating a low dimensional representation of the variation present in a set of spectra, e.g. reflection spectra recorded from a series of objects. The resulting low dimensional description may subseque ntly be input through variable selection schemes...... Fourier decomposition these new variables are located in frequency as well as well wavelength. The proposed algorithm is tested on 100 samples of NIR spectra of wheat....
Chen Lianwang; Yang Shuxin; Xie Furen; Lu Yuanzhong; Guo Ruomei
2006-01-01
Based on the active crustal block structures, the Holocene active faults and the wave velocity structures with a resolution of 1°× 1°, a two-dimensional finite element model for the tectonic stress-strain field of the Chinese mainland is constructed in the paper. Using GPS measurements, the velocity boundary conditions for the model are deduced, then, the annual change patterns of the present-day stress-strain field of the Chinese mainland are simulated.The results show that (1) the general pattern of the recent tectonic deformation in the Chinese mainland is governed by the interactions of its surrounding plates, of which, the Indian Plate plays a major role. There is a NNE-directed velocity distribution in the west of the Chinese mainland. The maximum slip rate appears at the collision boundary. The north-directed components decrease, while the east-directed components increase gradually from south to north and from west to east. In the east part, there is a general east-directed movement, with a certain amount of south-directed components. (2) The present-day tectonic stress field in the Chinese mainland has undergone the process of enhancement in recent years, and this process presents a general pattern of radiating eastwards from the Qinghai-Xizang (Tibet) Plateau as the center. The general pattern is similar to the ambient tectonic stress field, indicating the inheritance of contemporary tectonic deformation on the Chinese mainland. (3) The maximum principal strain presents an obvious pattern of being high in the west and low in the east. The tectonic movement in the west is stronger than that in the east. Large active faults are all located in the high-value zones of maximum principal strain. However, the magnitude of strain is smaller in the interior of the active crustal blocks, which are enclosed by these faults. (4) The stress-strain field of the Sichuan-Yunnan region is unique. It may not be governed by collision of plates alone but a combination of
Duality of Maximum Entropy and Minimum Divergence
Shinto Eguchi
2014-06-01
Full Text Available We discuss a special class of generalized divergence measures by the use of generator functions. Any divergence measure in the class is separated into the difference between cross and diagonal entropy. The diagonal entropy measure in the class associates with a model of maximum entropy distributions; the divergence measure leads to statistical estimation via minimization, for arbitrarily giving a statistical model. The dualistic relationship between the maximum entropy model and the minimum divergence estimation is explored in the framework of information geometry. The model of maximum entropy distributions is characterized to be totally geodesic with respect to the linear connection associated with the divergence. A natural extension for the classical theory for the maximum likelihood method under the maximum entropy model in terms of the Boltzmann-Gibbs-Shannon entropy is given. We discuss the duality in detail for Tsallis entropy as a typical example.
Scott, C E H; Eaton, M J; Nutton, R W; Wade, F A; Evans, S L; Pankaj, P
2017-01-01
Up to 40% of unicompartmental knee arthroplasty (UKA) revisions are performed for unexplained pain which may be caused by elevated proximal tibial bone strain. This study investigates the effect of tibial component metal backing and polyethylene thickness on bone strain in a cemented fixed-bearing medial UKA using a finite element model (FEM) validated experimentally by digital image correlation (DIC) and acoustic emission (AE). A total of ten composite tibias implanted with all-polyethylene (AP) and metal-backed (MB) tibial components were loaded to 2500 N. Cortical strain was measured using DIC and cancellous microdamage using AE. FEMs were created and validated and polyethylene thickness varied from 6 mm to 10 mm. The volume of cancellous bone exposed to 3000 µε and > 7000 µε maximum principal (tensile) microstrain was computed. Experimental AE data and the FEM volume of cancellous bone with compressive strain FEM data correlated: R = 0.838, R(2) = 0.702, percentage error 4.5% (p FEM strain patterns included MB lateral edge concentrations; AP concentrations at keel, peg and at the region of load application. Cancellous strains were higher in AP implants at all loads: 2.2- (10 mm) to 3.2-times (6 mm) the volume of cancellous bone compressively strained < -7000 µε. AP tibial components display greater volumes of pathologically overstrained cancellous bone than MB implants of the same geometry. Increasing AP thickness does not overcome these pathological forces and comes at the cost of greater bone resection.Cite this article: C. E. H. Scott, M. J. Eaton, R. W. Nutton, F. A. Wade, S. L. Evans, P. Pankaj. Metal-backed versus all-polyethylene unicompartmental knee arthroplasty: Proximal tibial strain in an experimentally validated finite element model. Bone Joint Res 2017;6:22-30. DOI:10.1302/2046-3758.61.BJR-2016-0142.R1. © 2017 Scott et al.
LIU Peng; WANG Zhongtao; LI Xinzhong; CHAN Andrew
2015-01-01
Principal stress axes rotation influences the stress-strain behavior of sand under wave loading. A constitutive model for sand, which considers principal stress orientation and is based on generalized plasticity theory, is proposed. The new model, which employs stress invariants and a discrete memory factor during reloading, is original because it quantifies model parameters using experimental data. Four sets of hollow torsion experiments were conducted to calibrate the parameters and predict the capability of the proposed model, which describes the effects of principal stress orientation on the behavior of sand. The results prove the effectiveness of the proposed calibration method.
COPD phenotype description using principal components analysis
Roy, Kay; Smith, Jacky; Kolsum, Umme
2009-01-01
BACKGROUND: Airway inflammation in COPD can be measured using biomarkers such as induced sputum and Fe(NO). This study set out to explore the heterogeneity of COPD using biomarkers of airway and systemic inflammation and pulmonary function by principal components analysis (PCA). SUBJECTS...... AND METHODS: In 127 COPD patients (mean FEV1 61%), pulmonary function, Fe(NO), plasma CRP and TNF-alpha, sputum differential cell counts and sputum IL8 (pg/ml) were measured. Principal components analysis as well as multivariate analysis was performed. RESULTS: PCA identified four main components (% variance...... associations between the variables within components 1 and 2. CONCLUSION: COPD is a multi dimensional disease. Unrelated components of disease were identified, including neutrophilic airway inflammation which was associated with systemic inflammation, and sputum eosinophils which were related to increased Fe...
Principals' transformational leadership and teachers' collective efficacy.
Dussault, Marc; Payette, Daniel; Leroux, Mathieu
2008-04-01
The study was designed to test the relationship of principals' transformational, transactional, and laissez-faire leadership with teachers' collective efficacy. Bandura's theory of efficacy applied to the group and Bass's transformational leadership theory were used as the theoretical framework. Participants included 487 French Canadian teachers from 40 public high schools. As expected, there were positive and significant correlations between principals' transformational and transactional leadership and teachers' collective efficacy. Also, there was a negative and significant correlation between laissez-faire leadership and teachers' collective efficacy. Moreover, regression analysis showed transformational leadership significantly enhanced the predictive capabilities of transactional leadership on teachers' collective efficacy. These results confirm the importance of leadership to predict collective efficacy and, by doing so, strengthen Bass's theory of leadership.
Quantum principal bundles and their characteristic classes
Durdevic, M
1996-01-01
A brief exposition of the general theory of characteristic classes of quantum principal bundles is given. The theory of quantum characteristic classes incorporates ideas of classical Weil theory into the conceptual framework of non-commutative differential geometry. A purely cohomological interpretation of the Weil homomorphism is given, together with a standard geometrical interpretation via quantum invariant polynomials. A natural spectral sequence is described. Some quantum phenomena appearing in the formalism are discussed.
Principal Portfolios: Recasting the Efficient Frontier
M. Hossein Partovi; Michael Caputo
2004-01-01
A new method of analyzing the efficient portfolio problem under the assumption that short sales are allowed is presented. It is based on the remarkable finding that the original asset set can be reorganized as a set of uncorrelated portfolios, here named principal portfolios. The original problem of portfolio selection from the existing, correlated assets is thereby traded for the reduced problem of choosing from a set of uncorrelated portfolios. These portfolios constitute a new investment e...
CHEN Liqun; Jean W.ZU; WU Jun
2004-01-01
To investigate the principal resonance in transverse nonlinear parametric vibration of an axially accelerating viscoelastic string, the method of multiple scales is applied directly to the nonlinear partial differential equation that governs the transverse vibration of the string. To derive the governing equation, Newton's second law, Lagrangean strain, and Kelvin's model are respectively used to account the dynamical relation, geometric nonlinearity and the viscoelasticity of the string material.Based on the solvability condition of eliminating the secular terms, closed form solutions are obtained for the amplitude and the existence conditions of nontrivial steady-state response of the principal parametric resonance. The Lyapunov linearized stability theory is employed to analyze the stability of the trivial and nontrivial solutions in the principal parametric resonance. Some numerical examples are presented to show the effects of the mean transport speed, the amplitude and the frequency of speed variation.
Principal component analysis for authorship attribution
Amir Jamak
2012-01-01
Full Text Available Background: To recognize the authors of the texts by the use of statistical tools, one first needs to decide about the features to be used as author characteristics, and then extract these features from texts. The features extracted from texts are mostly the counts of so called function words. Objectives: The data extracted are processed further to compress as a data with less number of features, such a way that the compressed data still has the power of effective discriminators. In this case feature space has less dimensionality then the text itself. Methods/Approach: In this paper, the data collected by counting words and characters in around a thousand paragraphs of each sample book, underwent a principal component analysis performed using neural networks. Once the analysis was complete, the first of the principal components is used to distinguish the books authored by a certain author. Results: The achieved results show that every author leaves a unique signature in written text that can be discovered by analyzing counts of short words per paragraph. Conclusions: In this article we have demonstrated that based on analyzing counts of short words per paragraph authorship could be traced using principal component analysis. Methodology could be used for other purposes, like fraud detection in auditing.
Multilevel sparse functional principal component analysis.
Di, Chongzhi; Crainiceanu, Ciprian M; Jank, Wolfgang S
2014-01-29
We consider analysis of sparsely sampled multilevel functional data, where the basic observational unit is a function and data have a natural hierarchy of basic units. An example is when functions are recorded at multiple visits for each subject. Multilevel functional principal component analysis (MFPCA; Di et al. 2009) was proposed for such data when functions are densely recorded. Here we consider the case when functions are sparsely sampled and may contain only a few observations per function. We exploit the multilevel structure of covariance operators and achieve data reduction by principal component decompositions at both between and within subject levels. We address inherent methodological differences in the sparse sampling context to: 1) estimate the covariance operators; 2) estimate the functional principal component scores; 3) predict the underlying curves. Through simulations the proposed method is able to discover dominating modes of variations and reconstruct underlying curves well even in sparse settings. Our approach is illustrated by two applications, the Sleep Heart Health Study and eBay auctions.
The Teaching Principal: An Untenable Position or a Promising Model?
Newton, Paul M.; Wallin, Dawn
2013-01-01
This paper reports on an interpretive study that examined the role of the teaching principal, particularly as it relates to principals' moral and legal requirement to work as instructional leaders for student learning. A teaching principal is defined as a principal who has a "double load" or dual roles in teaching and administration…
19 CFR 113.33 - Corporations as principals.
2010-04-01
... 19 Customs Duties 1 2010-04-01 2010-04-01 false Corporations as principals. 113.33 Section 113.33... TREASURY CUSTOMS BONDS Principals and Sureties § 113.33 Corporations as principals. (a) Name of corporation on the bonds. The name of a corporation executing a Customs bond as a principal, may be printed...
Principal Role Changes and Implications for Principalship Candidates.
Whitaker, Kathryn S.
1999-01-01
A principal who exchanged jobs with a university professor explores changing principal roles, using a case-study approach. Principals' working world is characterized by overwhelming responsibilities, information perplexity, and emotional anxiety. Principals would appreciate intrinsic and extrinsic rewards, support networks, university-school…
Principal Role Changes and Implications for Principalship Candidates.
Whitaker, Kathryn S.
1999-01-01
A principal who exchanged jobs with a university professor explores changing principal roles, using a case-study approach. Principals' working world is characterized by overwhelming responsibilities, information perplexity, and emotional anxiety. Principals would appreciate intrinsic and extrinsic rewards, support networks, university-school…
A dual method for maximum entropy restoration
Smith, C. B.
1979-01-01
A simple iterative dual algorithm for maximum entropy image restoration is presented. The dual algorithm involves fewer parameters than conventional minimization in the image space. Minicomputer test results for Fourier synthesis with inadequate phantom data are given.
Maximum Throughput in Multiple-Antenna Systems
Zamani, Mahdi
2012-01-01
The point-to-point multiple-antenna channel is investigated in uncorrelated block fading environment with Rayleigh distribution. The maximum throughput and maximum expected-rate of this channel are derived under the assumption that the transmitter is oblivious to the channel state information (CSI), however, the receiver has perfect CSI. First, we prove that in multiple-input single-output (MISO) channels, the optimum transmission strategy maximizing the throughput is to use all available antennas and perform equal power allocation with uncorrelated signals. Furthermore, to increase the expected-rate, multi-layer coding is applied. Analogously, we establish that sending uncorrelated signals and performing equal power allocation across all available antennas at each layer is optimum. A closed form expression for the maximum continuous-layer expected-rate of MISO channels is also obtained. Moreover, we investigate multiple-input multiple-output (MIMO) channels, and formulate the maximum throughput in the asympt...
Photoemission spectromicroscopy with MAXIMUM at Wisconsin
Ng, W.; Ray-Chaudhuri, A.K.; Cole, R.K.; Wallace, J.; Crossley, S.; Crossley, D.; Chen, G.; Green, M.; Guo, J.; Hansen, R.W.C.; Cerrina, F.; Margaritondo, G. (Dept. of Electrical Engineering, Dept. of Physics and Synchrotron Radiation Center, Univ. of Wisconsin, Madison (USA)); Underwood, J.H.; Korthright, J.; Perera, R.C.C. (Center for X-ray Optics, Accelerator and Fusion Research Div., Lawrence Berkeley Lab., CA (USA))
1990-06-01
We describe the development of the scanning photoemission spectromicroscope MAXIMUM at the Wisoncsin Synchrotron Radiation Center, which uses radiation from a 30-period undulator. The article includes a discussion of the first tests after the initial commissioning. (orig.).
Maximum-likelihood method in quantum estimation
Paris, M G A; Sacchi, M F
2001-01-01
The maximum-likelihood method for quantum estimation is reviewed and applied to the reconstruction of density matrix of spin and radiation as well as to the determination of several parameters of interest in quantum optics.
The maximum entropy technique. System's statistical description
Belashev, B Z
2002-01-01
The maximum entropy technique (MENT) is applied for searching the distribution functions of physical values. MENT takes into consideration the demand of maximum entropy, the characteristics of the system and the connection conditions, naturally. It is allowed to apply MENT for statistical description of closed and open systems. The examples in which MENT had been used for the description of the equilibrium and nonequilibrium states and the states far from the thermodynamical equilibrium are considered
19 CFR 114.23 - Maximum period.
2010-04-01
... 19 Customs Duties 1 2010-04-01 2010-04-01 false Maximum period. 114.23 Section 114.23 Customs... CARNETS Processing of Carnets § 114.23 Maximum period. (a) A.T.A. carnet. No A.T.A. carnet with a period of validity exceeding 1 year from date of issue shall be accepted. This period of validity cannot be...
Maximum-Likelihood Detection Of Noncoherent CPM
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.
Creep measurements confirm steady flow after stress maximum in extension of branched polymer melts
Javier Alvarez, Nicolas; Román Marín, José Manuel; Huang, Qian;
2013-01-01
We provide conclusive evidence of nonmonotonic mechanical behavior in the extension of long-chain branched polymer melts. While nonmonotonic behavior is known to occur for solids, for the case of polymeric melts, this phenomenon is in direct contrast with current theoretical models. We rule out...... the possibility of the overshoot being an experimental artifact by confirming the existence of steady flow after a maximum in the ratio of stress to strain rate versus strain under both constant stress and constant strain-rate kinematics. This observation indicates the omission of important physics from current...
Anglo-American views of Gavrilo Princip
Markovich Slobodan G.
2015-01-01
Full Text Available The paper deals with Western (Anglo-American views on the Sarajevo assassination/attentat and Gavrilo Princip. Articles on the assassination and Princip in two leading quality dailies (The Times and The New York Times have particularly been analysed as well as the views of leading historians and journalists who covered the subject including: R. G. D. Laffan, R. W. Seton-Watson, Winston Churchill, Sidney Fay, Bernadotte Schmitt, Rebecca West, A. J. P. Taylor, Vladimir Dedijer, Christopher Clark and Tim Butcher. In the West, the original general condemnation of the assassination and its main culprits was challenged when Rebecca West published her famous travelogue on Yugoslavia in 1941. Another Brit, the remarkable historian A. J. P. Taylor, had a much more positive view on the Sarajevo conspirators and blamed Germany and Austria-Hungary for the outbreak of the Great War. A turning point in Anglo-American perceptions was the publication of Vladimir Dedijer’s monumental book The Road to Sarajevo (1966, which humanised the main conspirators, a process initiated by R. West. Dedijer’s book was translated from English into all major Western languages and had an immediate impact on the understanding of the Sarajevo assassination. The rise of national antagonisms in Bosnia gradually alienated Princip from Bosnian Muslims and Croats, a process that began in the 1980s and was completed during the wars of the Yugoslav succession. Although all available sources clearly show that Princip, an ethnic Serb, gradually developed a broader Serbo-Croat and Yugoslav identity, he was ethnified and seen exclusively as a Serb by Bosnian Croats and Bosniaks and Western journalists in the 1990s. In the past century imagining Princip in Serbia and the West involved a whole spectrum of views. In interwar Anglo-American perceptions he was a fanatic and lunatic. He became humanised by Rebecca West (1941, A. J. P. Taylor showed understanding for his act (1956, he was fully
SEXUAL DIMORPHISM OF MAXIMUM FEMORAL LENGTH
Pandya A M
2011-04-01
Full Text Available Sexual identification from the skeletal parts has medico legal and anthropological importance. Present study aims to obtain values of maximum femoral length and to evaluate its possible usefulness in determining correct sexual identification. Study sample consisted of 184 dry, normal, adult, human femora (136 male & 48 female from skeletal collections of Anatomy department, M. P. Shah Medical College, Jamnagar, Gujarat. Maximum length of femur was considered as maximum vertical distance between upper end of head of femur and the lowest point on femoral condyle, measured with the osteometric board. Mean Values obtained were, 451.81 and 417.48 for right male and female, and 453.35 and 420.44 for left male and female respectively. Higher value in male was statistically highly significant (P< 0.001 on both sides. Demarking point (D.P. analysis of the data showed that right femora with maximum length more than 476.70 were definitely male and less than 379.99 were definitely female; while for left bones, femora with maximum length more than 484.49 were definitely male and less than 385.73 were definitely female. Maximum length identified 13.43% of right male femora, 4.35% of right female femora, 7.25% of left male femora and 8% of left female femora. [National J of Med Res 2011; 1(2.000: 67-70
Dan WU
2009-06-01
Full Text Available The principal-subordinate hierarchical multi-objective programming model of initial water rights allocation was developed based on the principle of coordinated and sustainable development of different regions and water sectors within a basin. With the precondition of strictly controlling maximum emissions rights, initial water rights were allocated between the first and the second levels of the hierarchy in order to promote fair and coordinated development across different regions of the basin and coordinated and efficient water use across different water sectors, realize the maximum comprehensive benefits to the basin, promote the unity of quantity and quality of initial water rights allocation, and eliminate water conflict across different regions and water sectors. According to interactive decision-making theory, a principal-subordinate hierarchical interactive iterative algorithm based on the satisfaction degree was developed and used to solve the initial water rights allocation model. A case study verified the validity of the model.
Dan WU; Feng-ping WU; Yan-ping CHEN
2009-01-01
The principal-subordinate hierarchical multi-objective programming model of initial water rights allocation was developed based on the principle of coordinated and sustainable development of different regions and water sectors within a basin. With the precondition of strictly controlling maximum emissions rights, initial water rights were allocated between the first and the second levels of the hierarchy in order to promote fair and coordinated development across different regions of the basin and coordinated and efficient water use across different water sectors, realize the maximum comprehensive benefits to the basin, promote the unity of quantity and quality of initial water rights allocation, and eliminate water conflict across different regions and water sectors. According to interactive decision-making theory, a principal-subordinate hierarchical interactive iterative algorithm based on the satisfaction degree was developed and used to solve the initial water rights allocation model. A case study verified the validity of the model.
Schmidt, Marvin; Schütze, Andreas; Seelecke, Stefan
2016-06-01
This paper discusses the influence of material strain and strain rate on efficiency and temperature span of elastocaloric cooling processes. The elastocaloric material, a newly developed quaternary Ni-Ti-Cu-V alloy, is characterized at different maximum strains and strain rates. The experiments are performed with a specially designed test setup, which enables the measurement of mechanical and thermal process parameters. The material efficiency is compared to the efficiency of the Carnot process at equivalent thermal operation conditions. This method allows for a direct comparison of the investigated material with other caloric materials.
Marvin Schmidt
2016-06-01
Full Text Available This paper discusses the influence of material strain and strain rate on efficiency and temperature span of elastocaloric cooling processes. The elastocaloric material, a newly developed quaternary Ni-Ti-Cu-V alloy, is characterized at different maximum strains and strain rates. The experiments are performed with a specially designed test setup, which enables the measurement of mechanical and thermal process parameters. The material efficiency is compared to the efficiency of the Carnot process at equivalent thermal operation conditions. This method allows for a direct comparison of the investigated material with other caloric materials.
Ozer, Niyazi
2013-01-01
The purpose of this study was to determine the primary school principals' views on trust in students and parents and also, to explore the relationships between principals' levels of professional burnout and their trust in students and parents. To this end, Principal Trust Survey and Friedman Principal Burnout scales were administered on…
Geobacteraceae strains and methods
Lovley, Derek R.; Nevin, Kelly P.; Yi, Hana
2015-07-07
Embodiments of the present invention provide a method of producing genetically modified strains of electricigenic microbes that are specifically adapted for the production of electrical current in microbial fuel cells, as well as strains produced by such methods and fuel cells using such strains. In preferred embodiments, the present invention provides genetically modified strains of Geobacter sulfurreducens and methods of using such strains.
Estimation of surface curvature from full-field shape data using principal component analysis
Sharma, Sameer; Vinuchakravarthy, S.; Subramanian, S. J.
2017-01-01
Three-dimensional digital image correlation (3D-DIC) is a popular image-based experimental technique for estimating surface shape, displacements and strains of deforming objects. In this technique, a calibrated stereo rig is used to obtain and stereo-match pairs of images of the object of interest from which the shapes of the imaged surface are then computed using the calibration parameters of the rig. Displacements are obtained by performing an additional temporal correlation of the shapes obtained at various stages of deformation and strains by smoothing and numerically differentiating the displacement data. Since strains are of primary importance in solid mechanics, significant efforts have been put into computation of strains from the measured displacement fields; however, much less attention has been paid to date to computation of curvature from the measured 3D surfaces. In this work, we address this gap by proposing a new method of computing curvature from full-field shape measurements using principal component analysis (PCA) along the lines of a similar work recently proposed to measure strains (Grama and Subramanian 2014 Exp. Mech. 54 913-33). PCA is a multivariate analysis tool that is widely used to reveal relationships between a large number of variables, reduce dimensionality and achieve significant denoising. This technique is applied here to identify dominant principal components in the shape fields measured by 3D-DIC and these principal components are then differentiated systematically to obtain the first and second fundamental forms used in the curvature calculation. The proposed method is first verified using synthetically generated noisy surfaces and then validated experimentally on some real world objects with known ground-truth curvatures.
Movement and strain conditions of active blocks in the Chinese mainland
LI; Yanxing; (李延兴); YANG; Guohua; (杨国华); LI; Zhi; (李; 智); GUO; Liangqian; (郭良迁); HUANG; Cheng; (黄珹); ZHU; Wenyao; (朱文耀); FU; Yang; (符; 养); WANG; Qi; (王; 琪); JIANG; Zaisen; (江在森); WANG; Min; (王; 敏)
2003-01-01
The definition of active block is given from the angles of crustal deformation and strain. The movement and strain parameters of active blocks are estimated according to the unified velocity field composed of the velocities at 1598 GPS stations obtained from GPS measurements carried out in the past years in the Chinese mainland and the surrounding areas. The movement and strain conditions of the blocks are analyzed. The active blocks in the Chinese mainland have a consistent E-trending movement component, but its N and S components are not consistent. The blocks in the western part have a consistent N-trending movement and the blocks in the eastern part have a consistent S-trending movement. In the area to the east of 90°E, that is the area from Himalayas block towards NE, the movement direction of the blocks rotates clockwisely and the movement rates of the blocks are different. Generally, the movement rate is large in the west and south and small in the east and north with a difference of 3 to 4 times between the rates in the west and east. The distributions of principal compressive strain directions of the blocks are also different. The principal strain of the blocks located to the west of 90oE is basically in the SN direction, the principal compressive strain of the blocks in the northeastern part of Qingzang plateau is roughly in the NE direction and the direction of principal compressive strain of the blocks in the southeastern part of Qingzang plateau rounds clockwisely the east end of Himalayas structure. In addition, the principal strain and shear strain rates of the blocks are also different. The Himalayas and Tianshan blocks have the largest principal compressive strain and the maximum shear strain rate. Then, Lhasa, Qiangtang, Southwest Yunnan (SW Yunnan), Qilian and Sichuan-Yunan (Chuan-Dian) blocks followed. The strain rate of the blocks in the eastern part is smaller. The estimation based on the stain condition indicates that Himalayas block is
Juliane Elisa Welke
2011-03-01
Full Text Available A part of apples destined to juice production is generally of poor quality. Apples from cold storage or recently harvest (ground harvested or low quality apples are stored under ambient conditions until they are processed. Since Penicillium expansum and P. griseofulvum are the principal fungal species isolated from stored apples in Brazil, the objective of this study was to investigate the ability of these strains to produce patulin in apples and report the consequences of this type of storage in loss of quality. The toxin was quantified using thin layer chromatography and charge-coupled device camera (TLC-CCD. The rate and quantities that P. expansum and P. griseofulvum can grow and produce patulin are highly dependent on the fungal strain and time. Lesion diameter resulted to be independent of the strain considered. The maximum period of time which apples were kept at cold storage (4 ºC without patulin accumulation was 27 days. When these apples were kept at 25 ºC during 3 days, both factors lesion diameter and patulin production increased significantly. These results confirm that time in which apples are taken out from cold storage room before juice production is critical in order to prevent patulin accumulation.
Maximum Likelihood Estimation of Time-Varying Loadings in High-Dimensional Factor Models
Mikkelsen, Jakob Guldbæk; Hillebrand, Eric; Urga, Giovanni
In this paper, we develop a maximum likelihood estimator of time-varying loadings in high-dimensional factor models. We specify the loadings to evolve as stationary vector autoregressions (VAR) and show that consistent estimates of the loadings parameters can be obtained by a two-step maximum...... likelihood estimation procedure. In the first step, principal components are extracted from the data to form factor estimates. In the second step, the parameters of the loadings VARs are estimated as a set of univariate regression models with time-varying coefficients. We document the finite...
Principal semantic components of language and the measurement of meaning.
Alexei V Samsonovich
Full Text Available Metric systems for semantics, or semantic cognitive maps, are allocations of words or other representations in a metric space based on their meaning. Existing methods for semantic mapping, such as Latent Semantic Analysis and Latent Dirichlet Allocation, are based on paradigms involving dissimilarity metrics. They typically do not take into account relations of antonymy and yield a large number of domain-specific semantic dimensions. Here, using a novel self-organization approach, we construct a low-dimensional, context-independent semantic map of natural language that represents simultaneously synonymy and antonymy. Emergent semantics of the map principal components are clearly identifiable: the first three correspond to the meanings of "good/bad" (valence, "calm/excited" (arousal, and "open/closed" (freedom, respectively. The semantic map is sufficiently robust to allow the automated extraction of synonyms and antonyms not originally in the dictionaries used to construct the map and to predict connotation from their coordinates. The map geometric characteristics include a limited number ( approximately 4 of statistically significant dimensions, a bimodal distribution of the first component, increasing kurtosis of subsequent (unimodal components, and a U-shaped maximum-spread planar projection. Both the semantic content and the main geometric features of the map are consistent between dictionaries (Microsoft Word and Princeton's WordNet, among Western languages (English, French, German, and Spanish, and with previously established psychometric measures. By defining the semantics of its dimensions, the constructed map provides a foundational metric system for the quantitative analysis of word meaning. Language can be viewed as a cumulative product of human experiences. Therefore, the extracted principal semantic dimensions may be useful to characterize the general semantic dimensions of the content of mental states. This is a fundamental step
Hooyer, T.S.; Iverson, N.R.; Lagroix, F.; Thomason, J.F.
2008-01-01
Wet-based portions of ice sheets may move primarily by shearing their till beds, resting in high sediment fluxes and the development of subglacial landforms. This model of glacier movement, which requires high bed shear strains, can be tested using till microstructural characteristics that evolve during till deformation. Here we examine the development of magnetic fabric using a ring shear device to defom two Wisconsin-age basal tills to shear strains as high as 70. Hysteresis experiments and the dependence of magnetic susceptibility of these tills on temperature demonstrate that anisotropy of magnetic susceptibility (AMS) develops during shear due to the rotation of primarily magnetite particles that are silt sized or smaller. At moderate shear strains (???6-25), principal axes of maximum magnetic susceptibility develop a strong fabric (S1 eignevalues of 0.83-0.96), without further strengthening at higher strains, During deformation, directions of maximum susceptibility cluster strongly in the direction of shear and plunge 'up-glacier,' consistent with the behavior of pebbles and sand particles studied in earlier experiments. In contrast, the magnitude of AMS does not vary systematically with strain and is small relative to its variability among samples; this is because most magnetite grains are contained as inclusions in larger particles and hence do not align during shear. Although processes other than pervasive bed deformation may result in strong flow parallel fabrics, AMS fabrics provide a rapid and objective means of identifying basal tills that have not been sheared sufficiently to be compatible with the bed deformation model. Copyright 2008 by the American Geophysical Union.
The maximum rotation of a galactic disc
Bottema, R
1997-01-01
The observed stellar velocity dispersions of galactic discs show that the maximum rotation of a disc is on average 63% of the observed maximum rotation. This criterion can, however, not be applied to small or low surface brightness (LSB) galaxies because such systems show, in general, a continuously rising rotation curve until the outermost measured radial position. That is why a general relation has been derived, giving the maximum rotation for a disc depending on the luminosity, surface brightness, and colour of the disc. As a physical basis of this relation serves an adopted fixed mass-to-light ratio as a function of colour. That functionality is consistent with results from population synthesis models and its absolute value is determined from the observed stellar velocity dispersions. The derived maximum disc rotation is compared with a number of observed maximum rotations, clearly demonstrating the need for appreciable amounts of dark matter in the disc region and even more so for LSB galaxies. Matters h...
Maximum permissible voltage of YBCO coated conductors
Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z.; Hong, Z.; Wang, D.; Zhou, H.; Shen, X.; Shen, C.
2014-06-01
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 (Ic) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the Ic 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.
Computing Rooted and Unrooted Maximum Consistent Supertrees
van Iersel, Leo
2009-01-01
A chief problem in phylogenetics and database theory is the computation of a maximum consistent tree from a set of rooted or unrooted trees. A standard input are triplets, rooted binary trees on three leaves, or quartets, unrooted binary trees on four leaves. We give exact algorithms constructing rooted and unrooted maximum consistent supertrees in time O(2^n n^5 m^2 log(m)) for a set of m triplets (quartets), each one distinctly leaf-labeled by some subset of n labels. The algorithms extend to weighted triplets (quartets). We further present fast exact algorithms for constructing rooted and unrooted maximum consistent trees in polynomial space. Finally, for a set T of m rooted or unrooted trees with maximum degree D and distinctly leaf-labeled by some subset of a set L of n labels, we compute, in O(2^{mD} n^m m^5 n^6 log(m)) time, a tree distinctly leaf-labeled by a maximum-size subset X of L that all trees in T, when restricted to X, are consistent with.
Maximum magnitude earthquakes induced by fluid injection
McGarr, Arthur F.
2014-01-01
Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.
Maximum magnitude earthquakes induced by fluid injection
McGarr, A.
2014-02-01
Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.
Principal normal indicatrices of closed space curves
Røgen, Peter
1997-01-01
A theorem due to J. Weiner, which also is proven by B. Solomon, implies that a principal normal indicatrix of a closed space curve with non-vanishing curvature has integrated geodesic curvature zero and contains no sub arc with integrated geodesic curvature Pi. We prove that the inverse problem...... always has solutions if one allows zero and negative curvature of space curves and explain why this not is true if non-vanishing curvature is required. This answers affirmatively an open question asked by W. Fenchel in 1950 under the above assumptions but in general this question is found to be answered...
Principal symbol of Euler-Lagrange operators
Fatibene, L.; Garruto, S.
2016-07-01
We shall introduce the principal symbol for quite a general class of (quasi linear) Euler-Lagrange operators and use them to characterise well-posed initial value problems in gauge covariant field theories. We shall clarify how constraints can arise in covariant Lagrangian theories by extending the standard treatment in GR and without resorting to Hamiltonian formalism. Finally as an example of application, we sketch a quantisation procedure based on what is done in LQG by framing it in a more general context which applies to general gauge covariant field theories.
Principal $G$-bundles over elliptic curves
Friedman, R; Witten, Edward; Friedman, Robert; Morgan, John W.; Witten, Edward
1997-01-01
Let $G$ be a simple and simply connected complex Lie group. We discuss the moduli space of holomorphic semistable principal $G$-bundles over an elliptic curve $E$. In particular, we give a new proof of a theorem of Looijenga and Bernshtein-Shvartsman, that the moduli space is a weighted projective space. The method of proof is to study the deformations of certain unstable bundles coming from special maximal parabolic subgroups of $G$. We also discuss the associated automorphism sheaves and universal bundles, as well as the relation between various universal bundles and spectral covers.
Radar fall detection using principal component analysis
Jokanovic, Branka; Amin, Moeness; Ahmad, Fauzia; Boashash, Boualem
2016-05-01
Falls are a major cause of fatal and nonfatal injuries in people aged 65 years and older. Radar has the potential to become one of the leading technologies for fall detection, thereby enabling the elderly to live independently. Existing techniques for fall detection using radar are based on manual feature extraction and require significant parameter tuning in order to provide successful detections. In this paper, we employ principal component analysis for fall detection, wherein eigen images of observed motions are employed for classification. Using real data, we demonstrate that the PCA based technique provides performance improvement over the conventional feature extraction methods.
... wrestling put people at risk for strains. Gymnastics, tennis, rowing, golf, and other sports that require extensive gripping can increase the risk of hand and forearm strains. Elbow strains sometimes occur in people who participate in ...
Treatment - muscle strain ... Question: How do you treat a muscle strain ? Answer: Rest the strained muscle and apply ice for the first few days after the injury. Anti-inflammatory medicines or acetaminophen ( ...
A muscle strain is the stretching or tearing of muscle fibers. A muscle strain can be caused by sports, exercise, a ... something that is too heavy. Symptoms of a muscle strain include pain, tightness, swelling, tenderness, and the ...
Reuland, Andrew J.
2012-01-01
School principals in Illinois face an ethical dilemma when evaluating tenured teachers. Giving an unsatisfactory rating and placing a tenured teacher under a remediation plan opens the door to a time-consuming process filled with legal and financial issues that will strain relationships in the school. However, giving a less than honest rating…
Influences of misfit strains on liquid phase heteroepitaxial growth
Lu, Yanli; Peng, Yingying; Yu, Genggeng; Chen, Zheng
2017-10-01
Influences of misfit strains with different signs on liquid phase heteroepitaxial growth are studied by binary phase field crystal model. It is amazing to find that double islands are formed because of lateral and vertical separation. The morphological evolution of epitaxial layer depends on signs of misfit strains. The maximum atomic layer thickness of double islands under negative misfit strain is larger than that of under positive misfit strain at the same evolutional time, and size differences between light and dark islands is much smaller under negative misfit strain than that of under positive misfit strain. In addition, concentration field and density field approximately have similar variational law along x direction under the same misfit strain but show opposite variational trend under misfit strains with different signs. Generally, free energy of epitaxial growth systems keeps similar variational trend under misfit strains with different signs.
Maximum Multiflow in Wireless Network Coding
Zhou, Jin-Yi; Jiang, Yong; Zheng, Hai-Tao
2012-01-01
In a multihop wireless network, wireless interference is crucial to the maximum multiflow (MMF) problem, which studies the maximum throughput between multiple pairs of sources and sinks. In this paper, we observe that network coding could help to decrease the impacts of wireless interference, and propose a framework to study the MMF problem for multihop wireless networks with network coding. Firstly, a network model is set up to describe the new conflict relations modified by network coding. Then, we formulate a linear programming problem to compute the maximum throughput and show its superiority over one in networks without coding. Finally, the MMF problem in wireless network coding is shown to be NP-hard and a polynomial approximation algorithm is proposed.
The Wiener maximum quadratic assignment problem
Cela, Eranda; Woeginger, Gerhard J
2011-01-01
We investigate a special case of the maximum quadratic assignment problem where one matrix is a product matrix and the other matrix is the distance matrix of a one-dimensional point set. We show that this special case, which we call the Wiener maximum quadratic assignment problem, is NP-hard in the ordinary sense and solvable in pseudo-polynomial time. Our approach also yields a polynomial time solution for the following problem from chemical graph theory: Find a tree that maximizes the Wiener index among all trees with a prescribed degree sequence. This settles an open problem from the literature.
Maximum confidence measurements via probabilistic quantum cloning
Zhang Wen-Hai; Yu Long-Bao; Cao Zhuo-Liang; Ye Liu
2013-01-01
Probabilistic quantum cloning (PQC) cannot copy a set of linearly dependent quantum states.In this paper,we show that if incorrect copies are allowed to be produced,linearly dependent quantum states may also be cloned by the PQC.By exploiting this kind of PQC to clone a special set of three linearly dependent quantum states,we derive the upper bound of the maximum confidence measure of a set.An explicit transformation of the maximum confidence measure is presented.
Maximum floodflows in the conterminous United States
Crippen, John R.; Bue, Conrad D.
1977-01-01
Peak floodflows from thousands of observation sites within the conterminous United States were studied to provide a guide for estimating potential maximum floodflows. Data were selected from 883 sites with drainage areas of less than 10,000 square miles (25,900 square kilometers) and were grouped into regional sets. Outstanding floods for each region were plotted on graphs, and envelope curves were computed that offer reasonable limits for estimates of maximum floods. The curves indicate that floods may occur that are two to three times greater than those known for most streams.
Revealing the Maximum Strength in Nanotwinned Copper
Lu, L.; Chen, X.; Huang, Xiaoxu
2009-01-01
The strength of polycrystalline materials increases with decreasing grain size. Below a critical size, smaller grains might lead to softening, as suggested by atomistic simulations. The strongest size should arise at a transition in deformation mechanism from lattice dislocation activities to grain...... 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...
The Maximum Resource Bin Packing Problem
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...
Maximum entropy analysis of EGRET data
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....
Revealing the Maximum Strength in Nanotwinned Copper
Lu, L.; Chen, X.; Huang, Xiaoxu
2009-01-01
The strength of polycrystalline materials increases with decreasing grain size. Below a critical size, smaller grains might lead to softening, as suggested by atomistic simulations. The strongest size should arise at a transition in deformation mechanism from lattice dislocation activities to grain...... 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...
Maximum phytoplankton concentrations in the sea
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 collected...... in the North Atlantic as part of the Bermuda Atlantic Time Series program as well as data collected off Southern California as part of the Southern California Bight Study program. The observed maximum particulate organic carbon and volumetric particle concentrations are consistent with the predictions...
Boosting Principal Component Analysis by Genetic Algorithm
Divya Somvanshi
2010-07-01
Full Text Available This paper presents a new method of feature extraction by combining principal component analysis and genetic algorithm. Use of multiple pre-processors in combination with principal component analysis generates alternate feature spaces for data representation. The present method works out the fusion of these multiple spaces to create higher dimensionality feature vectors. The fused feature vectors are given chromosome representation by taking feature components to be genes. Then these feature vectors are allowed to undergo genetic evolution individually. For genetic algorithm, initial population is created by calculating probability distance matrix, and by applying a probability distance metric such that all the genes which lie farther than a defined threshold are tripped to zero. The genetic evolution of fused feature vector brings out most significant feature components (genes as survivours. A measure of significance is adapted on the basis of frequency of occurrence of the surviving genes in the current population. Finally, the feature vector is obtained by weighting the original feature components in proportion to their significance. The present algorithm is validated in combination with a neural network classifier based on error backpropagation algorithm, and by analysing a number of benchmark datasets available in the open sources.Defence Science Journal, 2010, 60(4, pp.392-398, DOI:http://dx.doi.org/10.14429/dsj.60.495
Maximum-Entropy Meshfree Method for Compressible and Near-Incompressible Elasticity
Ortiz, A; Puso, M A; Sukumar, N
2009-09-04
Numerical integration errors and volumetric locking in the near-incompressible limit are two outstanding issues in Galerkin-based meshfree computations. In this paper, we present a modified Gaussian integration scheme on background cells for meshfree methods that alleviates errors in numerical integration and ensures patch test satisfaction to machine precision. Secondly, a locking-free small-strain elasticity formulation for meshfree methods is proposed, which draws on developments in assumed strain methods and nodal integration techniques. In this study, maximum-entropy basis functions are used; however, the generality of our approach permits the use of any meshfree approximation. Various benchmark problems in two-dimensional compressible and near-incompressible small strain elasticity are presented to demonstrate the accuracy and optimal convergence in the energy norm of the maximum-entropy meshfree formulation.
Effect of biosurfactant from two strains of Pseudomonas on ...
PRECIOUS
2009-12-01
Dec 1, 2009 ... Two Pseudomonas strains isolated from oil-contaminated soil which produce biosurfactant were studied. .... Refinery, Assam, India, each having a varied level of oil conta- mination. ..... Rapid method for monitoring maximum.
Guelorget, Bruno [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)]. E-mail: bruno.guelorget@utt.fr; Francois, Manuel [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Vial-Edwards, Cristian [Departemento de Ingenieria Mecanica y Metalurgica, Pontificia Universidad Catolica de Chile, Vicuna Mackenna 4860, 6904411 Santiago (Chile); Montay, Guillaume [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Daniel, Laurent [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Lu, Jian [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)
2006-01-15
In-plane Electronic Speckle Pattern Interferometry has been successfully used during tensile testing of semi-hard copper sheets in order to measure the strain rate. On one hand, heterogeneity in strain rate field has been found before the maximum of the tensile force ({epsilon} {sup t} {approx_equal} 19.4 and 25.4%, respectively). Thus, a localization phenomenon occurs before the classic Considere's criterion (dF = 0) for the diffuse neck initiation. On the other hand, strain rate measurement before fracture shows the moment where one of the two slip band systems becomes predominant, then strain concentrates in a small area, the shear band. Uncertainty evaluation has been carried out, which shows a very good accuracy of the total strain and the strain rate measurements.
Analysis of Photovoltaic Maximum Power Point Trackers
Veerachary, Mummadi
The photovoltaic generator exhibits a non-linear i-v characteristic and its maximum power point (MPP) varies with solar insolation. An intermediate switch-mode dc-dc converter is required to extract maximum power from the photovoltaic array. In this paper buck, boost and buck-boost topologies are considered and a detailed mathematical analysis, both for continuous and discontinuous inductor current operation, is given for MPP operation. The conditions on the connected load values and duty ratio are derived for achieving the satisfactory maximum power point operation. Further, it is shown that certain load values, falling out of the optimal range, will drive the operating point away from the true maximum power point. Detailed comparison of various topologies for MPPT is given. Selection of the converter topology for a given loading is discussed. Detailed discussion on circuit-oriented model development is given and then MPPT effectiveness of various converter systems is verified through simulations. Proposed theory and analysis is validated through experimental investigations.
On maximum cycle packings in polyhedral graphs
Peter Recht
2014-04-01
Full Text Available This paper addresses upper and lower bounds for the cardinality of a maximum vertex-/edge-disjoint cycle packing in a polyhedral graph G. Bounds on the cardinality of such packings are provided, that depend on the size, the order or the number of faces of G, respectively. Polyhedral graphs are constructed, that attain these bounds.
Hard graphs for the maximum clique problem
Hoede, Cornelis
1988-01-01
The maximum clique problem is one of the NP-complete problems. There are graphs for which a reduction technique exists that transforms the problem for these graphs into one for graphs with specific properties in polynomial time. The resulting graphs do not grow exponentially in order and number. Gra
Maximum Likelihood Estimation of Search Costs
J.L. Moraga-Gonzalez (José Luis); M.R. Wildenbeest (Matthijs)
2006-01-01
textabstractIn a recent paper Hong and Shum (forthcoming) present a structural methodology to estimate search cost distributions. We extend their approach to the case of oligopoly and present a maximum likelihood estimate of the search cost distribution. We apply our method to a data set of online p
Weak Scale From the Maximum Entropy Principle
Hamada, Yuta; Kawana, Kiyoharu
2015-01-01
The theory of multiverse and wormholes suggests that the parameters of the Standard Model are fixed in such a way that the radiation of the $S^{3}$ 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 Standard Model, 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 ) $v_{h}$, and show that it becomes maximum around $v_{h}={\\cal{O}}(300\\text{GeV})$ when the dimensionless couplings in the Standard Model, that is, the Higgs self coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by \\begin{equation} v_{h}\\sim\\frac{T_{BBN}^{2}}{M_{pl}y_{e}^{5}},\
Weak scale from the maximum entropy principle
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.
Global characterization of the Holocene Thermal Maximum
Renssen, H.; Seppä, H.; Crosta, X.; Goosse, H.; Roche, D.M.V.A.P.
2012-01-01
We analyze the global variations in the timing and magnitude of the Holocene Thermal Maximum (HTM) and their dependence on various forcings in transient simulations covering the last 9000 years (9 ka), performed with a global atmosphere-ocean-vegetation model. In these experiments, we consider the i
Instance Optimality of the Adaptive Maximum Strategy
L. Diening; C. Kreuzer; R. Stevenson
2016-01-01
In this paper, we prove that the standard adaptive finite element method with a (modified) maximum marking strategy is instance optimal for the total error, being the square root of the squared energy error plus the squared oscillation. This result will be derived in the model setting of Poisson’s e
Maximum phonation time: variability and reliability.
Speyer, Renée; Bogaardt, Hans C A; Passos, Valéria Lima; Roodenburg, Nel P H D; Zumach, Anne; Heijnen, Mariëlle A M; Baijens, Laura W J; Fleskens, Stijn J H M; Brunings, Jan W
2010-05-01
The objective of the study was to determine maximum phonation time reliability as a function of the number of trials, days, and raters in dysphonic and control subjects. Two groups of adult subjects participated in this reliability study: a group of outpatients with functional or organic dysphonia versus a group of healthy control subjects matched by age and gender. Over a period of maximally 6 weeks, three video recordings were made of five subjects' maximum phonation time trials. A panel of five experts were responsible for all measurements, including a repeated measurement of the subjects' first recordings. Patients showed significantly shorter maximum phonation times compared with healthy controls (on average, 6.6 seconds shorter). The averaged interclass correlation coefficient (ICC) over all raters per trial for the first day was 0.998. The averaged reliability coefficient per rater and per trial for repeated measurements of the first day's data was 0.997, indicating high intrarater reliability. The mean reliability coefficient per day for one trial was 0.939. When using five trials, the reliability increased to 0.987. The reliability over five trials for a single day was 0.836; for 2 days, 0.911; and for 3 days, 0.935. To conclude, the maximum phonation time has proven to be a highly reliable measure in voice assessment. A single rater is sufficient to provide highly reliable measurements.
Maximum Phonation Time: Variability and Reliability
R. Speyer; H.C.A. Bogaardt; V.L. Passos; N.P.H.D. Roodenburg; A. Zumach; M.A.M. Heijnen; L.W.J. Baijens; S.J.H.M. Fleskens; J.W. Brunings
2010-01-01
The objective of the study was to determine maximum phonation time reliability as a function of the number of trials, days, and raters in dysphonic and control subjects. Two groups of adult subjects participated in this reliability study: a group of outpatients with functional or organic dysphonia v
Maximum likelihood estimation of fractionally cointegrated systems
Lasak, Katarzyna
In this paper we consider a fractionally cointegrated error correction model and investigate asymptotic properties of the maximum likelihood (ML) estimators of the matrix of the cointe- gration relations, the degree of fractional cointegration, the matrix of the speed of adjustment...
Maximum likelihood estimation for integrated diffusion processes
Baltazar-Larios, Fernando; Sørensen, Michael
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...
Maximum gain of Yagi-Uda arrays
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....
The kidney is the principal organ mediating klotho effects.
Lindberg, Karolina; Amin, Risul; Moe, Orson W; Hu, Ming-Chang; Erben, Reinhold G; Östman Wernerson, Annika; Lanske, Beate; Olauson, Hannes; Larsson, Tobias E
2014-10-01
Klotho was discovered as an antiaging gene, and α-Klotho (Klotho) is expressed in multiple tissues with a broad set of biologic functions. Membrane-bound Klotho binds fibroblast growth factor 23 (FGF23), but a soluble form of Klotho is also produced by alternative splicing or cleavage of the extracellular domain of the membrane-bound protein. The relative organ-specific contributions to the levels and effects of circulating Klotho remain unknown. We explored these issues by generating a novel mouse strain with Klotho deleted throughout the nephron (Six2-KL(-/-)). Klotho shedding from Six2-KL(-/-) kidney explants was undetectable and the serum Klotho level was reduced by approximately 80% in Six2-KL(-/-) mice compared with wild-type littermates. Six2-KL(-/-) mice exhibited severe growth retardation, kyphosis, and premature death, closely resembling the phenotype of systemic Klotho knockout mice. Notable biochemical changes included hyperphosphatemia, hypercalcemia, hyperaldosteronism, and elevated levels of 1,25-dihydroxyvitamin D and Fgf23, consistent with disrupted renal Fgf23 signaling. Kidney histology demonstrated interstitial fibrosis and nephrocalcinosis in addition to absent dimorphic tubules. A direct comparative analysis between Six2-KL(-/-) and systemic Klotho knockout mice supports extensive, yet indistinguishable, extrarenal organ manifestations. Thus, our data reveal the kidney as the principal contributor of circulating Klotho and Klotho-induced antiaging traits.
Paulsen, T.; Wilson, T. J.; Demosthenous, C.; Millan, C.; Jarrard, R. D.; Laufer, A.
2013-12-01
Strain analyses of mechanically twinned calcite in veins and faults hosted by Neogene (13.6 Ma to 4.3 Ma) sedimentary and volcanic rocks recovered within the ANDRILL AND-1B drill core from the Terror Rift in the southern Ross Sea, Antarctica, yield prolate and oblate ellipsoids with principal shortening and extension strains ranging from 0.1% to 8.5%. The majority of samples show homogeneous coaxial strain predominantly characterized by subvertical shortening, which we attribute to lithostatic loading in an Andersonian normal faulting stress regime during sedimentary and ice sheet burial of the stratigraphic sequence. The overall paucity of a non-coaxial layer-parallel shortening signal in the AND-1B twin populations suggests that horizontal compressive stresses predicted by Neogene transtensional kinematic models for the rift system have been absent or of insufficient magnitude to cause a widespread noncoaxial strain overprint. Limited numbers of oriented samples yield a possible average ESE extension direction for the rift that is subparallel to other indicators of Neogene extension. The lack of horizontal shortening in the twin data suggests the Neogene Terror Rift system either lacks a strong longitudinal strike-slip component, or that spatial partitioning of strain controls the maximum shortening axes seen in rocks of this age.
Metabolic networks evolve towards states of maximum entropy production.
Unrean, Pornkamol; Srienc, Friedrich
2011-11-01
A metabolic network can be described by a set of elementary modes or pathways representing discrete metabolic states that support cell function. We have recently shown that in the most likely metabolic state the usage probability of individual elementary modes is distributed according to the Boltzmann distribution law while complying with the principle of maximum entropy production. To demonstrate that a metabolic network evolves towards such state we have carried out adaptive evolution experiments with Thermoanaerobacterium saccharolyticum operating with a reduced metabolic functionality based on a reduced set of elementary modes. In such reduced metabolic network metabolic fluxes can be conveniently computed from the measured metabolite secretion pattern. Over a time span of 300 generations the specific growth rate of the strain continuously increased together with a continuous increase in the rate of entropy production. We show that the rate of entropy production asymptotically approaches the maximum entropy production rate predicted from the state when the usage probability of individual elementary modes is distributed according to the Boltzmann distribution. Therefore, the outcome of evolution of a complex biological system can be predicted in highly quantitative terms using basic statistical mechanical principles.
Nonlinear principal component analysis and its applications
Mori, Yuichi; Makino, Naomichi
2016-01-01
This book expounds the principle and related applications of nonlinear principal component analysis (PCA), which is useful method to analyze mixed measurement levels data. In the part dealing with the principle, after a brief introduction of ordinary PCA, a PCA for categorical data (nominal and ordinal) is introduced as nonlinear PCA, in which an optimal scaling technique is used to quantify the categorical variables. The alternating least squares (ALS) is the main algorithm in the method. Multiple correspondence analysis (MCA), a special case of nonlinear PCA, is also introduced. All formulations in these methods are integrated in the same manner as matrix operations. Because any measurement levels data can be treated consistently as numerical data and ALS is a very powerful tool for estimations, the methods can be utilized in a variety of fields such as biometrics, econometrics, psychometrics, and sociology. In the applications part of the book, four applications are introduced: variable selection for mixed...
Regional principal color based saliency detection.
Jing Lou
Full Text Available Saliency detection is widely used in many visual applications like image segmentation, object recognition and classification. In this paper, we will introduce a new method to detect salient objects in natural images. The approach is based on a regional principal color contrast modal, which incorporates low-level and medium-level visual cues. The method allows a simple computation of color features and two categories of spatial relationships to a saliency map, achieving higher F-measure rates. At the same time, we present an interpolation approach to evaluate resulting curves, and analyze parameters selection. Our method enables the effective computation of arbitrary resolution images. Experimental results on a saliency database show that our approach produces high quality saliency maps and performs favorably against ten saliency detection algorithms.
Principal aspects of the Ordovician biotic radiation
无
2010-01-01
The Ordovician radiation is among the major bioevents in earth history that have drawn great attention from geologists all over the world, and there have been hundreds of publications treating various aspects of this radiation. The study of the event involves a broad spectrum of research fields and concerns many scientific questions. Many opinions and hypotheses have been proposed on the triggering and controlling factors of the radiation. Herein the authors critically review the study of the Ordovician radiation and dissect four principal aspects by synthesizing the studies over the past years: (1) relationships of the radiation to fossil clades, ecotypes, and environments, such as water depth, latitude, and climate; (2) the ecological structure and food webs of Ordovician marine organisms; (3) fossil records and true biodiversities; and (4) likely triggering and controlling factors of the Ordovician radiation. The authors also recommend approaches to furthering studies of these aspects.
Face Recognition Based on Principal Component Analysis
Ali Javed
2013-02-01
Full Text Available The purpose of the proposed research work is to develop a computer system that can recognize a person by comparing the characteristics of face to those of known individuals. The main focus is on frontal two dimensional images that are taken in a controlled environment i.e. the illumination and the background will be constant. All the other methods of person’s identification and verification like iris scan or finger print scan require high quality and costly equipment’s but in face recognition we only require a normal camera giving us a 2-D frontal image of the person that will be used for the process of the person’s recognition. Principal Component Analysis technique has been used in the proposed system of face recognition. The purpose is to compare the results of the technique under the different conditions and to find the most efficient approach for developing a facial recognition system
Principal components analysis of Jupiter VIMS spectra
Bellucci, G.; Formisano, V.; D'Aversa, E.; Brown, R.H.; Baines, K.H.; Bibring, J.-P.; Buratti, B.J.; Capaccioni, F.; Cerroni, P.; Clark, R.N.; Coradini, A.; Cruikshank, D.P.; Drossart, P.; Jaumann, R.; Langevin, Y.; Matson, D.L.; McCord, T.B.; Mennella, V.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, Christophe; Chamberlain, M.C.; Hansen, G.; Hibbits, K.; Showalter, M.; Filacchione, G.
2004-01-01
During Cassini - Jupiter flyby occurred in December 2000, Visual-Infrared mapping spectrometer (VIMS) instrument took several image cubes of Jupiter at different phase angles and distances. We have analysed the spectral images acquired by the VIMS visual channel by means of a principal component analysis technique (PCA). The original data set consists of 96 spectral images in the 0.35-1.05 ??m wavelength range. The product of the analysis are new PC bands, which contain all the spectral variance of the original data. These new components have been used to produce a map of Jupiter made of seven coherent spectral classes. The map confirms previously published work done on the Great Red Spot by using NIMS data. Some other new findings, presently under investigation, are presented. ?? 2004 Published by Elsevier Ltd on behalf of COSPAR.
Reinvention and the Principal-Agent Model
J. Ramón Gil García
2003-01-01
Full Text Available Existe una interesante polémica en el sector público, derivada de las tensiones existentes entre desempeño y flexibilidad administrativa por un lado, y rendición de cuentas y control, por el otro. El propósito de este artículo es discutir la utilidad del modelo agente principal para un mejor entendimiento de las tensiones entre desempeño y rendición de cuentas, así como analizar las similitudes y contradicciones de esta perspectiva teórica en comparación con el movimiento de reinvención del gobierno de la década de los noventa en Estados Unidos.
Principal Component Pursuit with Reduced Linear Measurements
Ganesh, Arvind; Wright, John; Ma, Yi
2012-01-01
In this paper, we study the problem of decomposing a superposition of a low-rank matrix and a sparse matrix when a relatively few linear measurements are available. This problem arises in many data processing tasks such as aligning multiple images or rectifying regular texture, where the goal is to recover a low-rank matrix with a large fraction of corrupted entries in the presence of nonlinear domain transformation. We consider a natural convex heuristic to this problem which is a variant to the recently proposed Principal Component Pursuit. We prove that under suitable conditions, this convex program guarantees to recover the correct low-rank and sparse components despite reduced measurements. Our analysis covers both random and deterministic measurement models.
Principal Components Analysis In Medical Imaging
Weaver, J. B.; Huddleston, A. L.
1986-06-01
Principal components analysis, PCA, is basically a data reduction technique. PCA has been used in several problems in diagnostic radiology: processing radioisotope brain scans (Ref.1), automatic alignment of radionuclide images (Ref. 2), processing MRI images (Ref. 3,4), analyzing first-pass cardiac studies (Ref. 5) correcting for attenuation in bone mineral measurements (Ref. 6) and in dual energy x-ray imaging (Ref. 6,7). This paper will progress as follows; a brief introduction to the mathematics of PCA will be followed by two brief examples of how PCA has been used in the literature. Finally my own experience with PCA in dual-energy x-ray imaging will be given.
Francis Bacon’s Qualification As A Principal Empiricist Philosopher
2011-01-01
The purpose of this paper is to determine if there is any basis for regarding FrancisBacon as a principal empiricist philosopher. This involves effort to determine whatconstitutes, in essence, the qualities of a principal empiricist philosopher. Are thereany criteria that qualify one as a principal empiricist philosopher? Proceeding with thisinquiry, our paper examines, on the one hand, the views of those who argue in defenceof Bacon’s qualification as a principal empiricist philosopher. Here...
Francis Bacons Qualification As A Principal Empiricist Philosopher
2011-01-01
The purpose of this paper is to determine if there is any basis for regarding Francis Bacon as a principal empiricist philosopher. This involves effort to determine what constitutes, in essence, the qualities of a principal empiricist philosopher. Are there any criteria that qualify one as a principal empiricist philosopher? Proceeding with this inquiry, our paper examines, on the one hand, the views of those who argue in defence of Bacon’s qualification as a principal empiricist philosopher....
Allocation of Decision-Making Authority with Principal's Reputation Concerns
Tsung-Sheng Tsai; Yasunari Tamada
2004-01-01
This paper analyzes the allocation of decision-making authority when the principal has reputation concerns. The principal can either keep the authority and consult the agent (an expert), or delegate the authority to the agent; however, the outside evaluator cannot observe the allocation of authority. Hence, delegation can provide a way to manipulate the principal's ex post reputation. In general, the principal keeps the authority too often when she has the opportunity of delegation. When the ...
A Preliminary Examination of the Impact of a Structured Principal Network on Principal Burnout
Tillery, Denise Artus
2012-01-01
This study examined the extent to which participation in a formal network has on a principal's personal perception of burnout as measured by the Maslach Burnout Inventory for Educators (MBI-E). The MBI-E consists of 22 questions with responses indicated on a 7 point Likert scale ranging from 0-6. It measures three constructs of emotional…
Hager, Rhonda Keever
2012-01-01
The importance of leadership is critical with current accountability for student performance. The increased accountability for school leaders has caused a change in leadership roles to incorporate collaboration and shared leadership. Assistant principals are included in the concept of distributive leadership. A review of the literature shows…
Quality M.Ed. Principal Licensure Degrees + Conscientious Students = Leader Principals
Guillaume, Cindy; Vitucci, Alanna
2015-01-01
Effective educational leadership at the principal level positively correlates with quality classroom teachers and improved student achievement (Portin et al., 2009). It also fosters a caring, supportive and inter-connected environment that inspires students and engages teachers (Seashore et al., 2010). Preparing competent, effective, and caring…
Principals' and Teachers' Views of Spirituality in Principal Leadership in Three Primary Schools
Gibson, Alaster
2014-01-01
This article discusses key findings from my doctoral research involving a qualitative case study inquiring into the lived experiences of spirituality in principal leadership and its influence on teachers and their teaching within three public primary school contexts in New Zealand. Spirituality is understood in this article as a complex and…
A Preliminary Examination of the Impact of a Structured Principal Network on Principal Burnout
Tillery, Denise Artus
2012-01-01
This study examined the extent to which participation in a formal network has on a principal's personal perception of burnout as measured by the Maslach Burnout Inventory for Educators (MBI-E). The MBI-E consists of 22 questions with responses indicated on a 7 point Likert scale ranging from 0-6. It measures three constructs of emotional…
Life cycle of Trypanosoma cruzi (y strain in mice
Pinto Pedro Luiz Silva
1999-01-01
Full Text Available Since 1958, we have studied experimental Chagas' disease (CD by subcutaneous inoculation of 1,000 blood forms of Trypanosoma cruzi (Y strain in Balb/C. mice. Evolution of parasitemia remained constant, beginning on the 5th and 6th day of the disease, increasing progressively, achieving a maximum on about the 30th day. After another month, only a few forms were present, and they disappeared from the circulation after the third month, as determined from direct examination of slides and the use of a Neubauer Counting Chamber. These events coincided with the appearance of amastigote nests in the tissues (especially the cardiac ones, starting the first week, and following the Gauss parasitemia curve, but they were not in parallel until the chronic stage. In 1997, we began to note the following changes: Parasites appeared in the circulation during the first week and disappeared starting on the 7th day, and there was a coincident absence of the amastigote nests in the tissues. A careful study verified that young forms in the evolutionary cycle of T. cruzi (epi + amastigotes began to appear alongside the trypomastigotes in the circulation on the 5th and 7th post-inoculation day. At the same time, rounded, oval, and spindle shapes were seen circulating through the capillaries and sinusoids of the tissues, principally of the hematopoietic organs. Stasis occurs because the diameter of the circulating parasites is greater than the vessels, and this makes them more visible. Examination of the sternal bone marrow revealed young cells with elongated forms and others truncated in the shape of a "C" occupying the internal surface of the blood cells that had empty central portions (erythrocytes?. We hypothesize that there could be a loss of virulence or mutation of the Y strain of Trypanosoma cruzi.
Principals' Perceptions of Instructional Stages Based on Felt Teaching Characteristics.
DeMoulin, Donald F.; Guyton, John W.
Whether principals could identify teaching traits and categorize these consistently as descriptors of instructional stages was studied by asking 145 randomly selected principals in public schools throughout Illinois and Indiana to characterize teacher behavior based on experience. Principals were asked to list instructional stages, yielding 161…
Suicide in Middle Level Schools: Implications for Principals.
Toepfer, Conrad F., Jr.
1986-01-01
Prevention of teenage suicide and coping with it when it occurs is an increasing concern for middle-level principals. This article focuses on specific implications of the youth suicide problem for middle-level principals with considerations for other principals as well. (Author/TE)
Leadership Behaviors and Its Relation with Principals' Management Experience
Mehdinezhad, Vali; Sardarzahi, Zaid
2016-01-01
This paper aims at studying the leadership behaviors reported by principals and observed by teachers and its relationship with management experience of principals. A quantitative method was used in this study. The target population included all principals and teachers of guidance schools and high schools in the Dashtiari District, Iran. A sample…
The Development of Assistant Principals: A Literature Review
Oleszewski, Ashley; Shoho, Alan; Barnett, Bruce
2012-01-01
Purpose: The purpose of this review is to add to the discussion of assistant principals (APs), a position that has been under-represented in the professional literature. Design/methodology/approach: An extensive search was undertaken on assistant principals, vice principals, and deputy head teachers from various sources, including journals,…
Consejeria de los directores (Principal Mentoring). ERIC Digest.
Malone, Robert J.
To help new principals succeed, school districts are capitalizing on senior administrators' expertise by adding mentor programs to the practical training programs for beginning principals. This ERIC Digest in Spanish examines the nature of mentorships and discusses how they can prepare principals for the next stage of their careers. Although…
New Principals in Africa: Preparation, Induction and Practice
Bush, Tony; Oduro, George K. T.
2006-01-01
Purpose: This paper aims to examine the challenges facing new principals in Africa. Design/methodology/approach: Based on recent research and literature, the paper analyses the experience of principals and proposes an induction model for principalship in Africa. Findings: School principals in Africa face a daunting challenge. They often work in…
Principal Socialization in One Virginia School District: A Phenomenological Investigation
Joppy, Dalphine A.
2013-01-01
This phenomenological investigation examines the lived experiences of school principals to discover how principals hired from within their school division perceive and make meaning of their organizational socialization experiences--their thoughts, feelings, beliefs, values, and assumptive worlds. Nineteen public school principals participated in…
Training the Trainers: Learning to Be a Principal Supervisor
Saltzman, Amy
2017-01-01
While most principal supervisors are former principals themselves, few come to the role with specific training in how to do the job effectively. For this reason, both the Washington, D.C., and Tulsa, Oklahoma, principal supervisor programs include a strong professional development component. In this article, the author takes a look inside these…
What It Takes to Be an Empowering Principal.
Peel, Henry A.; Walker, Bradford L.
1994-01-01
An ongoing cooperative research project in North Carolina provides some revealing data on principals who have successfully introduced school-based management. The project tracks 26 principals committed to teacher empowerment. The most supportive principals were strongly committed to school improvement, unafraid of risks or open communication lines…
Is School Value Added Indicative of Principal Quality?
Chiang, Hanley; Lipscomb, Stephen; Gill, Brian
2016-01-01
States across the country are developing systems for evaluating school principals on the basis of student achievement growth. A common approach is to hold principals accountable for the value added of their schools--that is, schools' contributions to student achievement growth. In theory, school value added can reflect not only principals'…
Assessing Multiple Stakeholders' Perceptions of an Effective Principal Evaluation System
Tran, Henry; Bon, Susan C.
2015-01-01
Existing principal evaluation research has failed to include the perspectives of multiple stakeholders. The present research study used focus group interviews to gather data about designing a principal evaluation process that includes these perspectives. Focus groups were conducted with principals, parents, certificated staff, and classified…
Professional Isolation and Performance at Work of School Principals.
Dussault, Marc; Thibodeau, Stephane
1997-01-01
Investigates the relationship between school principals' professional isolation and their performance at work. Suburban Quebec principals were administered French versions of the UCLA Loneliness Scale and the Self-Appraisal Instrument for Community College Administrators. Principals' professional isolation was negatively and significantly…
Leveraging Principal Evaluations to Scale up Instructional Improvement
Fenton, Ben
2016-01-01
Strong school leaders play a vital role in accelerating student achievement across a state. Research has found that principals account for 25 percent of a school's total impact on student achievement, and an above-average principal can raise student achievement by as much as 20 percentage points more than an average principal--equivalent to seven…
District Leadership for Effective Principal Evaluation and Support
Kimball, Steven M.; Arrigoni, Jessica; Clifford, Matthew; Yoder, Maureen; Milanowski, Anthony
2015-01-01
Research demonstrating principals' impact on student learning outcomes has fueled the shift from principals as facilities managers to an emphasis on instructional leadership (Hallinger & Heck, 1996; Leithwood, Louis, Anderson, & Wahlstrom, 2004; Marzano, Waters, & McNulty, 2005). Principals are under increasing pressure to carry out…
Contemporary Challenges and Changes: Principals' Leadership Practices in Malaysia
Jones, Michelle; Adams, Donnie; Joo, Mabel Tan Hwee; Muniandy, Vasu; Perera, Corinne Jaqueline; Harris, Alma
2015-01-01
This article outlines the findings from a contemporary study of principals' leadership practices in Malaysia as part of the 7 System Leadership Study. Recent policy developments within Malaysia have increased principals' accountability and have underlined the importance of the role of the principals in transforming school performance and student…
Model Selection Through Sparse Maximum Likelihood Estimation
Banerjee, Onureena; D'Aspremont, Alexandre
2007-01-01
We consider the problem of estimating the parameters of a Gaussian or binary distribution in such a way that the resulting undirected graphical model is sparse. Our approach is to solve a maximum likelihood problem with an added l_1-norm penalty term. The problem as formulated is convex but the memory requirements and complexity of existing interior point methods are prohibitive for problems with more than tens of nodes. We present two new algorithms for solving problems with at least a thousand nodes in the Gaussian case. Our first algorithm uses block coordinate descent, and can be interpreted as recursive l_1-norm penalized regression. Our second algorithm, based on Nesterov's first order method, yields a complexity estimate with a better dependence on problem size than existing interior point methods. Using a log determinant relaxation of the log partition function (Wainwright & Jordan (2006)), we show that these same algorithms can be used to solve an approximate sparse maximum likelihood problem for...
Maximum-entropy description of animal movement.
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.
Pareto versus lognormal: a maximum entropy test.
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.
Maximum Variance Hashing via Column Generation
Lei Luo
2013-01-01
item search. Recently, a number of data-dependent methods have been developed, reflecting the great potential of learning for hashing. Inspired by the classic nonlinear dimensionality reduction algorithm—maximum variance unfolding, we propose a novel unsupervised hashing method, named maximum variance hashing, in this work. The idea is to maximize the total variance of the hash codes while preserving the local structure of the training data. To solve the derived optimization problem, we propose a column generation algorithm, which directly learns the binary-valued hash functions. We then extend it using anchor graphs to reduce the computational cost. Experiments on large-scale image datasets demonstrate that the proposed method outperforms state-of-the-art hashing methods in many cases.
The Maximum Resource Bin Packing Problem
Boyar, J.; Epstein, L.; Favrholdt, L.M.
2006-01-01
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......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...... the competitive ratio of various natural algorithms. We study the general versions of the problems as well as the parameterized versions where there is an upper bound of on the item sizes, for some integer k....
Nonparametric Maximum Entropy Estimation on Information Diagrams
Martin, Elliot A; Meinke, Alexander; Děchtěrenko, Filip; Davidsen, Jörn
2016-01-01
Maximum entropy estimation is of broad interest for inferring properties of systems across many different disciplines. In this work, we significantly extend a technique we previously introduced for estimating the maximum entropy of a set of random discrete variables when conditioning on bivariate mutual informations and univariate entropies. Specifically, we show how to apply the concept to continuous random variables and vastly expand the types of information-theoretic quantities one can condition on. This allows us to establish a number of significant advantages of our approach over existing ones. Not only does our method perform favorably in the undersampled regime, where existing methods fail, but it also can be dramatically less computationally expensive as the cardinality of the variables increases. In addition, we propose a nonparametric formulation of connected informations and give an illustrative example showing how this agrees with the existing parametric formulation in cases of interest. We furthe...
Zipf's law, power laws and maximum entropy
Visser, Matt
2013-04-01
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.
Zipf's law, power laws, and maximum entropy
Visser, Matt
2012-01-01
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 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 article I argue that the 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.
Regions of constrained maximum likelihood parameter identifiability
Lee, C.-H.; Herget, C. J.
1975-01-01
This paper considers the parameter identification problem of general discrete-time, nonlinear, multiple-input/multiple-output dynamic systems with Gaussian-white distributed measurement errors. Knowledge of the system parameterization is assumed to be known. Regions of constrained maximum likelihood (CML) parameter identifiability are established. A computation procedure employing interval arithmetic is proposed for finding explicit regions of parameter identifiability for the case of linear systems. It is shown that if the vector of true parameters is locally CML identifiable, then with probability one, the vector of true parameters is a unique maximal point of the maximum likelihood function in the region of parameter identifiability and the CML estimation sequence will converge to the true parameters.
A Maximum Radius for Habitable Planets.
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.
Strain-based fatigue data for Ti-6Al-4V ELI under fully-reversed and mean strain loads.
Carrion, Patricio E; Shamsaei, Nima
2016-06-01
This article presents the experimental data supporting the study to obtain the mean strain/stress effects on the fatigue behavior of Ti-6Al-4V ELI. A series of strain-controlled fatigue experiments on Ti-6Al-4V ELI were performed at four strain ratios (-1, -0.5, 0, and 0.5). Two types of data are included for each specimen. These are the hysteresis stress-strain responses for the cycle in a log10 increment, and the maximum and minimum stress-strain responses for each cycle. Fatigue lives are also reported for all the experiments.
Strain-based fatigue data for Ti–6Al–4V ELI under fully-reversed and mean strain loads
Carrion, Patricio E.; Shamsaei, Nima
2016-01-01
This article presents the experimental data supporting the study to obtain the mean strain/stress effects on the fatigue behavior of Ti–6Al–4V ELI. A series of strain-controlled fatigue experiments on Ti–6Al–4V ELI were performed at four strain ratios (−1, −0.5, 0, and 0.5). Two types of data are included for each specimen. These are the hysteresis stress–strain responses for the cycle in a log10 increment, and the maximum and minimum stress–strain responses for each cycle. Fatigue lives are also reported for all the experiments. PMID:26952022
Strain-based fatigue data for Ti–6Al–4V ELI under fully-reversed and mean strain loads
Patricio E. Carrion
2016-06-01
Full Text Available This article presents the experimental data supporting the study to obtain the mean strain/stress effects on the fatigue behavior of Ti–6Al–4V ELI. A series of strain-controlled fatigue experiments on Ti–6Al–4V ELI were performed at four strain ratios (−1, −0.5, 0, and 0.5. Two types of data are included for each specimen. These are the hysteresis stress–strain responses for the cycle in a log10 increment, and the maximum and minimum stress–strain responses for each cycle. Fatigue lives are also reported for all the experiments.
Maximum Profit Configurations of Commercial Engines
Yiran Chen
2011-01-01
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 t...
A stochastic maximum principle via Malliavin calculus
Øksendal, Bernt; Zhou, Xun Yu; Meyer-Brandis, Thilo
2008-01-01
This paper considers a controlled It\\^o-L\\'evy process where the information available to the controller is possibly less than the overall information. All the system coefficients and the objective performance functional are allowed to be random, possibly non-Markovian. Malliavin calculus is employed to derive a maximum principle for the optimal control of such a system where the adjoint process is explicitly expressed.
Tissue radiation response with maximum Tsallis entropy.
Sotolongo-Grau, O; Rodríguez-Pérez, D; Antoranz, J C; Sotolongo-Costa, Oscar
2010-10-08
The expression of survival factors for radiation damaged cells is currently based on probabilistic assumptions and experimentally fitted for each tumor, radiation, and conditions. Here, we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypothesis, motivated by clinical observations. The obtained expression shows a remarkable agreement with the experimental data found in the literature.
Maximum Estrada Index of Bicyclic Graphs
Wang, Long; Wang, Yi
2012-01-01
Let $G$ be a simple graph of order $n$, let $\\lambda_1(G),\\lambda_2(G),...,\\lambda_n(G)$ be the eigenvalues of the adjacency matrix of $G$. The Esrada index of $G$ is defined as $EE(G)=\\sum_{i=1}^{n}e^{\\lambda_i(G)}$. In this paper we determine the unique graph with maximum Estrada index among bicyclic graphs with fixed order.
Maximum privacy without coherence, zero-error
Leung, Debbie; Yu, Nengkun
2016-09-01
We study the possible difference between the quantum and the private capacities of a quantum channel in the zero-error setting. For a family of channels introduced by Leung et al. [Phys. Rev. Lett. 113, 030512 (2014)], we demonstrate an extreme difference: the zero-error quantum capacity is zero, whereas the zero-error private capacity is maximum given the quantum output dimension.
Quantifying strain variability in modeling growth of Listeria monocytogenes
Aryani, D.; Besten, den H.M.W.; Hazeleger, W.C.; Zwietering, M.H.
2015-01-01
Prediction of microbial growth kinetics can differ from the actual behavior of the target microorganisms. In the present study, the impact of strain variability on maximum specific growth rate (µmax) (h- 1) was quantified using twenty Listeria monocytogenes strains. The µmax was determined as functi
Automatic maximum entropy spectral reconstruction in NMR.
Mobli, Mehdi; Maciejewski, Mark W; Gryk, Michael R; Hoch, Jeffrey C
2007-10-01
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.
Maximum entropy analysis of cosmic ray composition
Nosek, Dalibor; Vícha, Jakub; Trávníček, Petr; Nosková, Jana
2016-01-01
We focus on the primary composition of cosmic rays with the highest energies that cause extensive air showers in the Earth's atmosphere. A way of examining the two lowest order moments of the sample distribution of the depth of shower maximum is presented. The aim is to show that useful information about the composition of the primary beam can be inferred with limited knowledge we have about processes underlying these observations. In order to describe how the moments of the depth of shower maximum depend on the type of primary particles and their energies, we utilize a superposition model. Using the principle of maximum entropy, we are able to determine what trends in the primary composition are consistent with the input data, while relying on a limited amount of information from shower physics. Some capabilities and limitations of the proposed method are discussed. In order to achieve a realistic description of the primary mass composition, we pay special attention to the choice of the parameters of the sup...
A Maximum Resonant Set of Polyomino Graphs
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.
The maximum rate of mammal evolution
Evans, Alistair R.; Jones, David; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Fitzgerald, Erich M. G.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Okie, Jordan G.; Saarinen, Juha J.; Sibly, Richard M.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica M.; Uhen, Mark D.
2012-03-01
How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes.
Minimal Length, Friedmann Equations and Maximum Density
Awad, Adel
2014-01-01
Inspired by Jacobson's thermodynamic approach[gr-qc/9504004], Cai et al [hep-th/0501055,hep-th/0609128] have shown the emergence of Friedmann equations from the first law of thermodynamics. We extend Akbar--Cai derivation [hep-th/0609128] 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 $p(\\rho,a)$ 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 w...
Maximum saliency bias in binocular fusion
Lu, Yuhao; Stafford, Tom; Fox, Charles
2016-07-01
Subjective experience at any instant consists of a single ("unitary"), coherent interpretation of sense data rather than a "Bayesian blur" of alternatives. However, computation of Bayes-optimal actions has no role for unitary perception, instead being required to integrate over every possible action-percept pair to maximise expected utility. So what is the role of unitary coherent percepts, and how are they computed? Recent work provided objective evidence for non-Bayes-optimal, unitary coherent, perception and action in humans; and further suggested that the percept selected is not the maximum a posteriori percept but is instead affected by utility. The present study uses a binocular fusion task first to reproduce the same effect in a new domain, and second, to test multiple hypotheses about exactly how utility may affect the percept. After accounting for high experimental noise, it finds that both Bayes optimality (maximise expected utility) and the previously proposed maximum-utility hypothesis are outperformed in fitting the data by a modified maximum-salience hypothesis, using unsigned utility magnitudes in place of signed utilities in the bias function.
The maximum rate of mammal evolution
Evans, Alistair R.; Jones, David; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Fitzgerald, Erich M. G.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Okie, Jordan G.; Saarinen, Juha J.; Sibly, Richard M.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica M.; Uhen, Mark D.
2012-01-01
How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous–Paleogene (K–Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes. PMID:22308461
The maximum rate of mammal evolution.
Evans, Alistair R; Jones, David; Boyer, Alison G; Brown, James H; Costa, Daniel P; Ernest, S K Morgan; Fitzgerald, Erich M G; Fortelius, Mikael; Gittleman, John L; Hamilton, Marcus J; Harding, Larisa E; Lintulaakso, Kari; Lyons, S Kathleen; Okie, Jordan G; Saarinen, Juha J; Sibly, Richard M; Smith, Felisa A; Stephens, Patrick R; Theodor, Jessica M; Uhen, Mark D
2012-03-13
How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes.
Della Sala, Matthew R.; Klar, Hans W.; Lindle, Jane Clark; Reese, Kenyae L.; Knoeppel, Robert C.; Campbell, Michael; Buskey, Frederick C.
2013-01-01
Despite the key role that principals play in leading schoolwide change, districts' efforts to support principals are often limited, particularly in rural settings. In this article, we report the preliminary findings of a cross-district mentoring program for nine midcareer rural school principals. The collaboratively developed human resource…
Della Sala, Matthew R.; Klar, Hans W.; Lindle, Jane Clark; Reese, Kenyae L.; Knoeppel, Robert C.; Campbell, Michael; Buskey, Frederick C.
2013-01-01
Despite the key role that principals play in leading schoolwide change, districts' efforts to support principals are often limited, particularly in rural settings. In this article, we report the preliminary findings of a cross-district mentoring program for nine midcareer rural school principals. The collaboratively developed human resource…
Shape Modelling Using Maximum Autocorrelation Factors
Larsen, Rasmus
2001-01-01
of the training set are in reality a time series, e.g.\\$\\backslash\\$ snapshots of a beating heart during the cardiac cycle or when the shapes are slices of a 3D structure, e.g. the spinal cord. Second, in almost all applications a natural order of the landmark points along the contour of the shape is introduced......This paper addresses the problems of generating a low dimensional representation of the shape variation present in a training set after alignment using Procrustes analysis and projection into shape tangent space. We will extend the use of principal components analysis in the original formulation...... of Active Shape Models by Timothy Cootes and Christopher Taylor by building new information into the model. This new information consists of two types of prior knowledge. First, in many situation we will be given an ordering of the shapes of the training set. This situation occurs when the shapes...
Automatic Classification of Staphylococci by Principal-Component Analysis and a Gradient Method1
Hill, L. R.; Silvestri, L. G.; Ihm, P.; Farchi, G.; Lanciani, P.
1965-01-01
Hill, L. R. (Università Statale, Milano, Italy), L. G. Silvestri, P. Ihm, G. Farchi, and P. Lanciani. Automatic classification of staphylococci by principal-component analysis and a gradient method. J. Bacteriol. 89:1393–1401. 1965.—Forty-nine strains from the species Staphylococcus aureus, S. saprophyticus, S. lactis, S. afermentans, and S. roseus were submitted to different taxometric analyses; clustering was performed by single linkage, by the unweighted pair group method, and by principal-component analysis followed by a gradient method. Results were substantially the same with all methods. All S. aureus clustered together, sharply separated from S. roseus and S. afermentans; S. lactis and S. saprophyticus fell between, with the latter nearer to S. aureus. The main purpose of this study was to introduce a new taxometric technique, based on principal-component analysis followed by a gradient method, and to compare it with some other methods in current use. Advantages of the new method are complete automation and therefore greater objectivity, execution of the clustering in a space of reduced dimensions in which different characters have different weights, easy recognition of taxonomically important characters, and opportunity for representing clusters in three-dimensional models; the principal disadvantage is the need for large computer facilities. Images PMID:14293013
Principal components analysis of population admixture.
Jianzhong Ma
Full Text Available With the availability of high-density genotype information, principal components analysis (PCA is now routinely used to detect and quantify the genetic structure of populations in both population genetics and genetic epidemiology. An important issue is how to make appropriate and correct inferences about population relationships from the results of PCA, especially when admixed individuals are included in the analysis. We extend our recently developed theoretical formulation of PCA to allow for admixed populations. Because the sampled individuals are treated as features, our generalized formulation of PCA directly relates the pattern of the scatter plot of the top eigenvectors to the admixture proportions and parameters reflecting the population relationships, and thus can provide valuable guidance on how to properly interpret the results of PCA in practice. Using our formulation, we theoretically justify the diagnostic of two-way admixture. More importantly, our theoretical investigations based on the proposed formulation yield a diagnostic of multi-way admixture. For instance, we found that admixed individuals with three parental populations are distributed inside the triangle formed by their parental populations and divide the triangle into three smaller triangles whose areas have the same proportions in the big triangle as the corresponding admixture proportions. We tested and illustrated these findings using simulated data and data from HapMap III and the Human Genome Diversity Project.
Kakon Montua Ajua, Shantal
2012-01-01
Quality leadership preparation has been shown to have positive influences on leadership practices of graduates. With five formal categories of leadership training programmes in the decentralized Finnish educational system, little is known about the leadership practices of graduates. This study explored the applicability of training on principals’ self-assessed leadership practices in Central Finland. Eight semi-structured individual interviews were conducted with principals from schools i...
Maximum power operation of interacting molecular motors
Golubeva, Natalia; Imparato, Alberto
2013-01-01
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......, 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....
Maximum a posteriori decoder for digital communications
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.
Kernel-based Maximum Entropy Clustering
JIANG Wei; QU Jiao; LI Benxi
2007-01-01
With the development of Support Vector Machine (SVM),the "kernel method" has been studied in a general way.In this paper,we present a novel Kernel-based Maximum Entropy Clustering algorithm (KMEC).By using mercer kernel functions,the proposed algorithm is firstly map the data from their original space to high dimensional space where the data are expected to be more separable,then perform MEC clustering in the feature space.The experimental results show that the proposed method has better performance in the non-hyperspherical and complex data structure.
The sun and heliosphere at solar maximum.
Smith, E J; Marsden, R G; Balogh, A; Gloeckler, G; Geiss, J; McComas, D J; McKibben, R B; MacDowall, R J; Lanzerotti, L J; Krupp, N; Krueger, H; Landgraf, M
2003-11-14
Recent Ulysses observations from the Sun's equator to the poles reveal fundamental properties of the three-dimensional heliosphere at the maximum in solar activity. The heliospheric magnetic field originates from a magnetic dipole oriented nearly perpendicular to, instead of nearly parallel to, the Sun's rotation axis. Magnetic fields, solar wind, and energetic charged particles from low-latitude sources reach all latitudes, including the polar caps. The very fast high-latitude wind and polar coronal holes disappear and reappear together. Solar wind speed continues to be inversely correlated with coronal temperature. The cosmic ray flux is reduced symmetrically at all latitudes.
Conductivity maximum in a charged colloidal suspension
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.
Maximum entropy signal restoration with linear programming
Mastin, G.A.; Hanson, R.J.
1988-05-01
Dantzig's bounded-variable method is used to express the maximum entropy restoration problem as a linear programming problem. This is done by approximating the nonlinear objective function with piecewise linear segments, then bounding the variables as a function of the number of segments used. The use of a linear programming approach allows equality constraints found in the traditional Lagrange multiplier method to be relaxed. A robust revised simplex algorithm is used to implement the restoration. Experimental results from 128- and 512-point signal restorations are presented.
COMPARISON BETWEEN FORMULAS OF MAXIMUM SHIP SQUAT
PETRU SERGIU SERBAN
2016-06-01
Full Text Available Ship squat is a combined effect of ship’s draft and trim increase due to ship motion in limited navigation conditions. Over time, researchers conducted tests on models and ships to find a mathematical formula that can define squat. Various forms of calculating squat can be found in the literature. Among those most commonly used are of Barrass, Millward, Eryuzlu or ICORELS. This paper presents a comparison between the squat formulas to see the differences between them and which one provides the most satisfactory results. In this respect a cargo ship at different speeds was considered as a model for maximum squat calculations in canal navigation conditions.
Multi-Channel Maximum Likelihood Pitch Estimation
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...
Maximum entropy PDF projection: A review
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.
CORA: Emission Line Fitting with Maximum Likelihood
Ness, Jan-Uwe; Wichmann, Rainer
2011-12-01
CORA analyzes emission line spectra with low count numbers and fits them to a line using the maximum likelihood technique. CORA uses a rigorous application of Poisson statistics. From the assumption of Poissonian noise, the software derives the probability for a model of the emission line spectrum to represent the measured spectrum. The likelihood function is used as a criterion for optimizing the parameters of the theoretical spectrum and a fixed point equation is derived allowing an efficient way to obtain line fluxes. CORA has been applied to an X-ray spectrum with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra observatory.
Dynamical maximum entropy approach to flocking
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.
Maximum Temperature Detection System for Integrated Circuits
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.
Zipf's law and maximum sustainable growth
Malevergne, Y; Sornette, D
2010-01-01
Zipf's law states that the number of firms with size greater than S is inversely proportional to S. Most explanations start with Gibrat's rule of proportional growth but require additional constraints. We show that Gibrat's rule, at all firm levels, yields Zipf's law under a balance condition between the effective growth rate of incumbent firms (which includes their possible demise) and the growth rate of investments in entrant firms. Remarkably, Zipf's law is the signature of the long-term optimal allocation of resources that ensures the maximum sustainable growth rate of an economy.
Prediction Models on Distribution of Inherent Strains in T Type Welding Structure
Peng HE; Jicai FENG; Jiecai HAN; Yiyu QIAN
2003-01-01
A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. The method of predicting maximum hardness Hv(y, z) and maximum inherent strain gmax is given
Maximum entropy production and the fluctuation theorem
Dewar, R C [Unite EPHYSE, INRA Centre de Bordeaux-Aquitaine, BP 81, 33883 Villenave d' Ornon Cedex (France)
2005-05-27
Recently the author used an information theoretical formulation of non-equilibrium statistical mechanics (MaxEnt) to derive the fluctuation theorem (FT) concerning the probability of second law violating phase-space paths. A less rigorous argument leading to the variational principle of maximum entropy production (MEP) was also given. Here a more rigorous and general mathematical derivation of MEP from MaxEnt is presented, and the relationship between MEP and the FT is thereby clarified. Specifically, it is shown that the FT allows a general orthogonality property of maximum information entropy to be extended to entropy production itself, from which MEP then follows. The new derivation highlights MEP and the FT as generic properties of MaxEnt probability distributions involving anti-symmetric constraints, independently of any physical interpretation. Physically, MEP applies to the entropy production of those macroscopic fluxes that are free to vary under the imposed constraints, and corresponds to selection of the most probable macroscopic flux configuration. In special cases MaxEnt also leads to various upper bound transport principles. The relationship between MaxEnt and previous theories of irreversible processes due to Onsager, Prigogine and Ziegler is also clarified in the light of these results. (letter to the editor)
Thermodynamic hardness and the maximum hardness principle
Franco-Pérez, Marco; Gázquez, José L.; Ayers, Paul W.; Vela, Alberto
2017-08-01
An alternative definition of hardness (called the thermodynamic hardness) within the grand canonical ensemble formalism is proposed in terms of the partial derivative of the electronic chemical potential with respect to the thermodynamic chemical potential of the reservoir, keeping the temperature and the external potential constant. This temperature dependent definition may be interpreted as a measure of the propensity of a system to go through a charge transfer process when it interacts with other species, and thus it keeps the philosophy of the original definition. When the derivative is expressed in terms of the three-state ensemble model, in the regime of low temperatures and up to temperatures of chemical interest, one finds that for zero fractional charge, the thermodynamic hardness is proportional to T-1(I -A ) , where I is the first ionization potential, A is the electron affinity, and T is the temperature. However, the thermodynamic hardness is nearly zero when the fractional charge is different from zero. Thus, through the present definition, one avoids the presence of the Dirac delta function. We show that the chemical hardness defined in this way provides meaningful and discernible information about the hardness properties of a chemical species exhibiting integer or a fractional average number of electrons, and this analysis allowed us to establish a link between the maximum possible value of the hardness here defined, with the minimum softness principle, showing that both principles are related to minimum fractional charge and maximum stability conditions.
Maximum Likelihood Analysis in the PEN Experiment
Lehman, Martin
2013-10-01
The experimental determination of the π+ -->e+ ν (γ) decay branching ratio currently provides the most accurate test of lepton universality. The PEN experiment at PSI, Switzerland, aims to improve the present world average experimental precision of 3 . 3 ×10-3 to 5 ×10-4 using a stopped beam approach. During runs in 2008-10, PEN has acquired over 2 ×107 πe 2 events. The experiment includes active beam detectors (degrader, mini TPC, target), central MWPC tracking with plastic scintillator hodoscopes, and a spherical pure CsI electromagnetic shower calorimeter. The final branching ratio will be calculated using a maximum likelihood analysis. This analysis assigns each event a probability for 5 processes (π+ -->e+ ν , π+ -->μ+ ν , decay-in-flight, pile-up, and hadronic events) using Monte Carlo verified probability distribution functions of our observables (energies, times, etc). A progress report on the PEN maximum likelihood analysis will be presented. Work supported by NSF grant PHY-0970013.
A numerical method for determining the strain rate intensity factor under plane strain conditions
Alexandrov, S.; Kuo, C.-Y.; Jeng, Y.-R.
2016-07-01
Using the classical model of rigid perfectly plastic solids, the strain rate intensity factor has been previously introduced as the coefficient of the leading singular term in a series expansion of the equivalent strain rate in the vicinity of maximum friction surfaces. Since then, many strain rate intensity factors have been determined by means of analytical and semi-analytical solutions. However, no attempt has been made to develop a numerical method for calculating the strain rate intensity factor. This paper presents such a method for planar flow. The method is based on the theory of characteristics. First, the strain rate intensity factor is derived in characteristic coordinates. Then, a standard numerical slip-line technique is supplemented with a procedure to calculate the strain rate intensity factor. The distribution of the strain rate intensity factor along the friction surface in compression of a layer between two parallel plates is determined. A high accuracy of this numerical solution for the strain rate intensity factor is confirmed by comparison with an analytic solution. It is shown that the distribution of the strain rate intensity factor is in general discontinuous.
M. Cova
2015-07-01
Full Text Available The critical plane calculation for multiaxial damage assessment is often a demanding task, particularly for large FEM models of real components. Anyway, in actual engineering requests, sometime, it is possible to take advantage of the specific properties of the investigated case. This paper deals with the problem of a mechanical component loaded by multiple, but “time-separated”, multiaxial external loads. The specific material damage is dependent from the max principal stress variation with a significant mean stress sensitivity too. A specifically fitted procedure was developed for a fast computation, at each node of a large FEM model, of the direction undergoing the maximum fatigue damage; the procedure is defined according to an effective stress definition based on the max principal stress amplitude and mean value. The procedure is presented in a general form, applicable to the similar cases.
Lake Basin Fetch and Maximum Length/Width
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...
Characteristics of present-day active strain field of Chinese mainland
GUO Liang-qian; LI Yan-xing; YANG Guo-hua; HU Xin-kang
2008-01-01
On the basis of the GPS data obtained from repeated measurements carried out in 2004 and 2007, the horizontal principal strain of the Chinese mainland is calculated, which shows that the direction of principal compressive strain axis of each subplate is basically consistent with the P-axis of focal mechanism solution and the principal compressive stress axis acquired by geological method. It indicates that the crustal tectonic stress field is relatively stable in regions in a long time. The principal compressive stress axes of Qinghai-Tibet and Xinjiang subplates in the western part of Chinese mainland direct to NS and NNE-SSW, which are controlled by the force from the collision of the Eurasia Plate and India Plate. The principal compressive strain axes of Heilongjiang and North China subplates in the eastern part direct to ENE-WSW, which shows that they are subject to the force from the collision and underthrust of the Eurasia Plate to the North America and Pacific plates. At the same time, they are also affected by the lateral force from Qinghai-Tibet and Xinjiang subplates. The principal compressive strain axis of South China plate is WNW-ESE, which reflects that it is affected by the force from the collision of Philippine Sea Plate and Eurasia Plate and it is also subject to the lateral force from Qinghai-Tibet subplate. It is apparent from the comparison between the principal compressive strain axes in the periods of 2004-2007 and 2001-2004 that the acting directions of principal compressive stress of subplates in both periods are basically consistent. However, there is certain difference between their directional concentrations of principal compressive stress axes. The surface strain rates of different tectonic units in both periods indicate that the events predominating by compressive variation decrease, while the events predominating by tensile change increase.
Lenka JAKUBOVIČOVÁ
2014-09-01
Full Text Available Article deals with influence of mutual slewing of roller bearing rings on the principal stresses and their distribution at the contact area. Profile of rolling element is logarithmic. Roller bearing has been loaded by maximum specified load only in radial direction according to the ISO/TS 16281. In practice, the real roller bearings are not loaded only in the radial direction. Therefore, the angle alfa has been gradually slewed from alfa = 0' to 8' and equivalent principal stresses have been evaluated. This change influenced on contact conditions and contact stress distribution has changed.
Obturator internus muscle strains
Caoimhe Byrne, MB BCh, BAO
2017-03-01
Full Text Available We report 2 cases of obturator internus muscle strains. The injuries occurred in young male athletes involved in kicking sports. Case 1 details an acute obturator internus muscle strain with associated adductor longus strain. Case 2 details an overuse injury of the bilateral obturator internus muscles. In each case, magnetic resonance imaging played a crucial role in accurate diagnosis.
Metabolic activities of Lactobacillus spp. strains isolated from kefir.
Yüksekdag, Zehra Nur; Beyath, Yavuz; Aslim, Belma
2004-06-01
A total of 21 strains of Lactobacillus species were isolated from Turkish kefir samples, in order to select the most suitable strains according to their metabolic activities including probiotic properties. As a result of the identification tests, 21 Lactobacillus isolates were identified as L. acidophilus (4%), L. helveticus (9%), L. brevis (9%), L. bulgaricus (14%), L. plantarum (14%), L. casei (19%) and L. lactis (28%). The amount of produced lactic acid, hydrogen peroxide, proteolytic activity, and acetaldehyde productions of Lactobacillus spp. were determined. Different amounts of lactic acid were produced by strains studies; however, lactic acid levels were 1.7-11.4 mg/mL. All strains produced hydrogen peroxide. L. bulgaricus Z14L strain showed no proteolytic activity, L. casei Z6L strain produced the maximum amount (0.16 mg/mL) of proteolytic activity. Acetaldehyde concentration produced in Lactobacillus strains ranged between 0.88-3.52 microg/mL.
Maximum entropy principle and texture formation
Arminjon, M; Arminjon, Mayeul; Imbault, Didier
2006-01-01
The macro-to-micro transition in a heterogeneous material is envisaged as the selection of a probability distribution by the Principle of Maximum Entropy (MAXENT). The material is made of constituents, e.g. given crystal orientations. Each constituent is itself made of a large number of elementary constituents. The relevant probability is the volume fraction of the elementary constituents that belong to a given constituent and undergo a given stimulus. Assuming only obvious constraints in MAXENT means describing a maximally disordered material. This is proved to have the same average stimulus in each constituent. By adding a constraint in MAXENT, a new model, potentially interesting e.g. for texture prediction, is obtained.
MLDS: Maximum Likelihood Difference Scaling in R
Kenneth Knoblauch
2008-01-01
Full Text Available The MLDS package in the R programming language can be used to estimate perceptual scales based on the results of psychophysical experiments using the method of difference scaling. In a difference scaling experiment, observers compare two supra-threshold differences (a,b and (c,d on each trial. The approach is based on a stochastic model of how the observer decides which perceptual difference (or interval (a,b or (c,d is greater, and the parameters of the model are estimated using a maximum likelihood criterion. We also propose a method to test the model by evaluating the self-consistency of the estimated scale. The package includes an example in which an observer judges the differences in correlation between scatterplots. The example may be readily adapted to estimate perceptual scales for arbitrary physical continua.
Maximum Profit Configurations of Commercial Engines
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.
Maximum Segment Sum, Monadically (distilled tutorial
Jeremy Gibbons
2011-09-01
Full Text Available The maximum segment sum problem is to compute, given a list of integers, the largest of the sums of the contiguous segments of that list. This problem specification maps directly onto a cubic-time algorithm; however, there is a very elegant linear-time solution too. The problem is a classic exercise in the mathematics of program construction, illustrating important principles such as calculational development, pointfree reasoning, algebraic structure, and datatype-genericity. Here, we take a sideways look at the datatype-generic version of the problem in terms of monadic functional programming, instead of the traditional relational approach; the presentation is tutorial in style, and leavened with exercises for the reader.
Maximum Information and Quantum Prediction Algorithms
McElwaine, J N
1997-01-01
This paper describes an algorithm for selecting a consistent set within the consistent histories approach to quantum mechanics and investigates its properties. The algorithm uses a maximum information principle to select from among the consistent sets formed by projections defined by the Schmidt decomposition. The algorithm unconditionally predicts the possible events in closed quantum systems and ascribes probabilities to these events. A simple spin model is described and a complete classification of all exactly consistent sets of histories formed from Schmidt projections in the model is proved. This result is used to show that for this example the algorithm selects a physically realistic set. Other tentative suggestions in the literature for set selection algorithms using ideas from information theory are discussed.
Maximum process problems in optimal control theory
Goran Peskir
2005-01-01
Full Text Available Given a standard Brownian motion (Btt≥0 and the equation of motion dXt=vtdt+2dBt, we set St=max0≤s≤tXs and consider the optimal control problem supvE(Sτ−Cτ, where c>0 and the supremum is taken over all admissible controls v satisfying vt∈[μ0,μ1] for all t up to τ=inf{t>0|Xt∉(ℓ0,ℓ1} with μ0g∗(St, where s↦g∗(s is a switching curve that is determined explicitly (as the unique solution to a nonlinear differential equation. The solution found demonstrates that the problem formulations based on a maximum functional can be successfully included in optimal control theory (calculus of variations in addition to the classic problem formulations due to Lagrange, Mayer, and Bolza.
Maximum Spectral Luminous Efficacy of White Light
Murphy, T W
2013-01-01
As lighting efficiency improves, it is useful to understand the theoretical limits to luminous efficacy for light that we perceive as white. Independent of the efficiency with which photons are generated, there exists a spectrally-imposed limit to the luminous efficacy of any source of photons. We find that, depending on the acceptable bandpass and---to a lesser extent---the color temperature of the light, the ideal white light source achieves a spectral luminous efficacy of 250--370 lm/W. This is consistent with previous calculations, but here we explore the maximum luminous efficacy as a function of photopic sensitivity threshold, color temperature, and color rendering index; deriving peak performance as a function of all three parameters. We also present example experimental spectra from a variety of light sources, quantifying the intrinsic efficacy of their spectral distributions.
Maximum entropy model for business cycle synchronization
Xi, Ning; Muneepeerakul, Rachata; Azaele, Sandro; Wang, Yougui
2014-11-01
The global economy is a complex dynamical system, whose cyclical fluctuations can mainly be characterized by simultaneous recessions or expansions of major economies. Thus, the researches on the synchronization phenomenon are key to understanding and controlling the dynamics of the global economy. Based on a pairwise maximum entropy model, we analyze the business cycle synchronization of the G7 economic system. We obtain a pairwise-interaction network, which exhibits certain clustering structure and accounts for 45% of the entire structure of the interactions within the G7 system. We also find that the pairwise interactions become increasingly inadequate in capturing the synchronization as the size of economic system grows. Thus, higher-order interactions must be taken into account when investigating behaviors of large economic systems.
Quantum gravity momentum representation and maximum energy
Moffat, J. W.
2016-11-01
We use the idea of the symmetry between the spacetime coordinates xμ and the energy-momentum pμ in quantum theory to construct a momentum space quantum gravity geometry with a metric sμν and a curvature tensor Pλ μνρ. For a closed maximally symmetric momentum space with a constant 3-curvature, the volume of the p-space admits a cutoff with an invariant maximum momentum a. A Wheeler-DeWitt-type wave equation is obtained in the momentum space representation. The vacuum energy density and the self-energy of a charged particle are shown to be finite, and modifications of the electromagnetic radiation density and the entropy density of a system of particles occur for high frequencies.
Video segmentation using Maximum Entropy Model
QIN Li-juan; ZHUANG Yue-ting; PAN Yun-he; WU Fei
2005-01-01
Detecting objects of interest from a video sequence is a fundamental and critical task in automated visual surveillance.Most current approaches only focus on discriminating moving objects by background subtraction whether or not the objects of interest can be moving or stationary. In this paper, we propose layers segmentation to detect both moving and stationary target objects from surveillance video. We extend the Maximum Entropy (ME) statistical model to segment layers with features, which are collected by constructing a codebook with a set of codewords for each pixel. We also indicate how the training models are used for the discrimination of target objects in surveillance video. Our experimental results are presented in terms of the success rate and the segmenting precision.
Parallel Microcracks-based Ultrasensitive and Highly Stretchable Strain Sensors.
Amjadi, Morteza; Turan, Mehmet; Clementson, Cameron P; Sitti, Metin
2016-03-01
There is an increasing demand for flexible, skin-attachable, and wearable strain sensors due to their various potential applications. However, achieving strain sensors with both high sensitivity and high stretchability is still a grand challenge. Here, we propose highly sensitive and stretchable strain sensors based on the reversible microcrack formation in composite thin films. Controllable parallel microcracks are generated in graphite thin films coated on elastomer films. Sensors made of graphite thin films with short microcracks possess high gauge factors (maximum value of 522.6) and stretchability (ε ≥ 50%), whereas sensors with long microcracks show ultrahigh sensitivity (maximum value of 11,344) with limited stretchability (ε ≤ 50%). We demonstrate the high performance strain sensing of our sensors in both small and large strain sensing applications such as human physiological activity recognition, human body large motion capturing, vibration detection, pressure sensing, and soft robotics.
Evaluation of pliers' grip spans in the maximum gripping task and sub-maximum cutting task.
Kim, Dae-Min; Kong, Yong-Ku
2016-12-01
A total of 25 males participated to investigate the effects of the grip spans of pliers on the total grip force, individual finger forces and muscle activities in the maximum gripping task and wire-cutting tasks. In the maximum gripping task, results showed that the 50-mm grip span had significantly higher total grip strength than the other grip spans. In the cutting task, the 50-mm grip span also showed significantly higher grip strength than the 65-mm and 80-mm grip spans, whereas the muscle activities showed a higher value at 80-mm grip span. The ratios of cutting force to maximum grip strength were also investigated. Ratios of 30.3%, 31.3% and 41.3% were obtained by grip spans of 50-mm, 65-mm, and 80-mm, respectively. Thus, the 50-mm grip span for pliers might be recommended to provide maximum exertion in gripping tasks, as well as lower maximum-cutting force ratios in the cutting tasks.
Cosmic shear measurement with maximum likelihood and maximum a posteriori inference
Hall, Alex
2016-01-01
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 very promising results. We find that the introduction of an intrinsic shape prior mitigates 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 sub-dominant. We show how biases propagate to shear estima...
Incremental Tensor Principal Component Analysis for Handwritten Digit Recognition
Chang Liu
2014-01-01
Full Text Available To overcome the shortcomings of traditional dimensionality reduction algorithms, incremental tensor principal component analysis (ITPCA based on updated-SVD technique algorithm is proposed in this paper. This paper proves the relationship between PCA, 2DPCA, MPCA, and the graph embedding framework theoretically and derives the incremental learning procedure to add single sample and multiple samples in detail. The experiments on handwritten digit recognition have demonstrated that ITPCA has achieved better recognition performance than that of vector-based principal component analysis (PCA, incremental principal component analysis (IPCA, and multilinear principal component analysis (MPCA algorithms. At the same time, ITPCA also has lower time and space complexity.
Do Qualification, Experience and Age Matter for Principals Leadership Styles?
Muhammad Javed Sawati
2013-07-01
Full Text Available The main focus of present study was to find out the prevalent leadership styles of principals in government schools of Khyber Pakhtunkhwa and to find relationship of leadership styles with qualifications, age and experience of the principals. On the basis of analyzed data, four major leadership styles of the principals were identified as Eclectic, Democratic, Autocratic, and Free-rein. However, a small proportion of the principal had no dominant leadership style. This study shows that principals’ leadership styles have no significant correlation with age, experience and qualification.
FUZZY PRINCIPAL COMPONENT ANALYSIS AND ITS KERNEL BASED MODEL
无
2007-01-01
Principal Component Analysis (PCA) is one of the most important feature extraction methods, and Kernel Principal Component Analysis (KPCA) is a nonlinear extension of PCA based on kernel methods. In real world, each input data may not be fully assigned to one class and it may partially belong to other classes. Based on the theory of fuzzy sets, this paper presents Fuzzy Principal Component Analysis (FPCA) and its nonlinear extension model, i.e., Kernel-based Fuzzy Principal Component Analysis (KFPCA). The experimental results indicate that the proposed algorithms have good performances.
Principal leadership in new teacher induction: Becoming agents of change
FINNEY CHERIAN
2008-02-01
Full Text Available This small-scale pilot study investigated the role of school principals in the induction of new teachers in Ontario, Canada. Building upon the theoretical framework of Bolman and Deal (2002, as well as interviews, document analysis, and review of extant literature, the following findings were established: (a Principals expressed that the educative mentorship of novices requires the engagement of the entireschool community; and (b Principals, veterans, and novices saw teaching as an intellectual, moral, and political endeavor that required their collective involvement. We suggest that principals employ the notion of “communities of practice” to instill a culture of support for new teacher induction.
Principal succession: The socialisation of a primary school principal in South Africa
Gertruida M. Steyn
2013-04-01
Full Text Available This study focussed on the socialisation of a new principal in a South African primary school with a strong Christian culture. He was appointed when the predecessor retired after more than two decades. The conceptual framework focuses on the three phases of socialisation: professional socialisation, organisational socialisation and occupational identity, which are used to interpret the study. A qualitative study, which occurred during two phases, investigated the phenomenon, principal succession, in the particular school. The data collection methods included a number of interviews with the principal, a focus group interview with staff members who experienced the previous principal’s leadership practice, and individual interviews with staff members. The following categories emerged from the data analysis: Recalling the previous principal: ‘One sees Mr X [the predecessor] everywhere’; Entry and orientation: ‘I found it intimidating initially’; and Immersion and reshaping: ‘Reins that previously were a bit slack, he is now pulling tight’.Die sosialisering van ’n primêre skoolhoof in Suid-Afrika. Hierdie studie het gefokus op die sosialisering van ’n nuwe skoolhoof in ’n Suid-Afrikaanse primêre skool met ’n sterk Christelike kultuur. Hy is aangestel toe sy voorganger ná meer as twee dekades afgetree het. Die konseptuele raamwerk, wat gebruik is om die bevindinge te interpreteer, het op die drie fases van sosialisering gefokus, naamlik professionele sosialisering, organisatoriese sosialisering en beroepsidentiteit. ’n Kwalitatiewe ondersoek na die skoolhoofopvolgingverskynsel in die bepaalde skool is in twee fases gedoen. Die data-insamelingsmetodes het ’n aantal onderhoude met die skoolhoof, ’n fokusgroeponderhoud met personeellede wat ook onder leierskap van die vorige skoolhoof gewerk het en individuele onderhoude met personeellede ingesluit. Tydens die data-analise het die volgende kategorieë na vore gekom
Mapping ash properties using principal components analysis
Pereira, Paulo; Brevik, Eric; Cerda, Artemi; Ubeda, Xavier; Novara, Agata; Francos, Marcos; Rodrigo-Comino, Jesus; Bogunovic, Igor; Khaledian, Yones
2017-04-01
In post-fire environments ash has important benefits for soils, such as protection and source of nutrients, crucial for vegetation recuperation (Jordan et al., 2016; Pereira et al., 2015a; 2016a,b). The thickness and distribution of ash are fundamental aspects for soil protection (Cerdà and Doerr, 2008; Pereira et al., 2015b) and the severity at which was produced is important for the type and amount of elements that is released in soil solution (Bodi et al., 2014). Ash is very mobile material, and it is important were it will be deposited. Until the first rainfalls are is very mobile. After it, bind in the soil surface and is harder to erode. Mapping ash properties in the immediate period after fire is complex, since it is constantly moving (Pereira et al., 2015b). However, is an important task, since according the amount and type of ash produced we can identify the degree of soil protection and the nutrients that will be dissolved. The objective of this work is to apply to map ash properties (CaCO3, pH, and select extractable elements) using a principal component analysis (PCA) in the immediate period after the fire. Four days after the fire we established a grid in a 9x27 m area and took ash samples every 3 meters for a total of 40 sampling points (Pereira et al., 2017). The PCA identified 5 different factors. Factor 1 identified high loadings in electrical conductivity, calcium, and magnesium and negative with aluminum and iron, while Factor 3 had high positive loadings in total phosphorous and silica. Factor 3 showed high positive loadings in sodium and potassium, factor 4 high negative loadings in CaCO3 and pH, and factor 5 high loadings in sodium and potassium. The experimental variograms of the extracted factors showed that the Gaussian model was the most precise to model factor 1, the linear to model factor 2 and the wave hole effect to model factor 3, 4 and 5. The maps produced confirm the patternd observed in the experimental variograms. Factor 1 and 2
2016-01-01
The invention relates to a strain gauge of a carrier layer and a meandering measurement grid positioned on the carrier layer, wherein the strain gauge comprises two reinforcement members positioned on the carrier layer at opposite ends of the measurement grid in the axial direction....... The reinforcement members are each placed within a certain axial distance to the measurement grid with the axial distance being equal to or smaller than a factor times the grid spacing. The invention further relates to a multi-axial strain gauge such as a bi-axial strain gauge or a strain gauge rosette where each...... of the strain gauges comprises reinforcement members. The invention further relates to a method for manufacturing a strain gauge as mentioned above....
Ground movement at Somma-Vesuvius from Last Glacial Maximum
Marturano, Aldo; Aiello, Giuseppe; Barra, Diana; Fedele, Lorenzo; Morra, Vincenzo
2012-01-01
Detailed micropalaeontological and petrochemical analyses of rock samples from two boreholes drilled at the archaeological excavations of Herculaneum, ~ 7 km west of the Somma -Vesuvius crater, allowed reconstruction of the Late Quaternary palaeoenvironmental evolution of the site. The data provide clear evidence for ground uplift movements involving the studied area. The Holocenic sedimentary sequence on which the archaeological remains of Herculaneum rest has risen several meters at an average rate of ~ 4 mm/yr. The uplift has involved the western apron of the volcano and the Sebeto-Volla Plain, a populous area including the eastern suburbs of Naples. This is consistent with earlier evidence for similar uplift for the areas of Pompeii and Sarno valley (SE of the volcano) and the Somma -Vesuvius eastern apron. An axisimmetric deep source of strain is considered responsible for the long-term uplift affecting the whole Somma -Vesuvius edifice. The deformation pattern can be modeled as a single pressure source, sited in the lower crust and surrounded by a shell of Maxwell viscoelastic medium, which experienced a pressure pulse that began at the Last Glacial Maximum.
Maximum host survival at intermediate parasite infection intensities.
Martin Stjernman
Full Text Available BACKGROUND: Although parasitism has been acknowledged as an important selective force in the evolution of host life histories, studies of fitness effects of parasites in wild populations have yielded mixed results. One reason for this may be that most studies only test for a linear relationship between infection intensity and host fitness. If resistance to parasites is costly, however, fitness may be reduced both for hosts with low infection intensities (cost of resistance and high infection intensities (cost of parasitism, such that individuals with intermediate infection intensities have highest fitness. Under this scenario one would expect a non-linear relationship between infection intensity and fitness. METHODOLOGY/PRINCIPAL FINDINGS: Using data from blue tits (Cyanistes caeruleus in southern Sweden, we investigated the relationship between the intensity of infection of its blood parasite (Haemoproteus majoris and host survival to the following winter. Presence and intensity of parasite infections were determined by microscopy and confirmed using PCR of a 480 bp section of the cytochrome-b-gene. While a linear model suggested no relationship between parasite intensity and survival (F = 0.01, p = 0.94, a non-linear model showed a significant negative quadratic effect (quadratic parasite intensity: F = 4.65, p = 0.032; linear parasite intensity F = 4.47, p = 0.035. Visualization using the cubic spline technique showed maximum survival at intermediate parasite intensities. CONCLUSIONS/SIGNIFICANCE: Our results indicate that failing to recognize the potential for a non-linear relationship between parasite infection intensity and host fitness may lead to the potentially erroneous conclusion that the parasite is harmless to its host. Here we show that high parasite intensities indeed reduced survival, but this effect was masked by reduced survival for birds heavily suppressing their parasite intensities. Reduced survival among hosts with low
Principal leadership style, school performance, and principal effectiveness in Dubai schools
Ibrahim, Ali S.
2013-01-01
Full Text Available This study investigated whether a correlation exists between the principal’s leadership style and both a performance level and b the principal’s effectiveness in schools in Dubai. It also investigated whether the correlations change according to the principal’s gender, years of experience, and the level of the school (primary, intermediate, and secondary. Data on principals’ leadership styles and effectiveness were collected through Avolio and Bass’ (1995 Multifactor Leadership Questionnaire (MLQ completed by teachers in 34 government schools. Data on school performance were obtained from the 2010 Dubai Schools Inspection Bureau report. The study found that the transformational leadership style was most frequently employed, followed by the transactional style, and then the passive or avoidant style. The study found a positive correlation between the principal leadership style and his/her effectiveness, but found no correlation with school performance. Finally, principal style and effectiveness differed according to the principal’s gender and the level of the school, but not according to the principal’s years of experience. Findings of this study open a new area of research on school principalship, performance, and effectiveness in the UAE.
Longitudinal growth strains in five clones of Eucalyptus tereticornis Sm.
Pankaj Aggarwal; Shakti Chauhan
2013-01-01
We studied the variability in longitudinal growth strains and wood basic density in five-year old trees from five clones (one tree per clone) of Eucalyptus tereticornis.Mean longitudinal growth strain in clones ranged from 466 to 876 μm.There was a significant difference between clones in growth strains and wood basic density.Clone 10 exhibited maximum growth strains and basic density,whereas clone 3 and clone 7 exhibited minimum growth strains and basic density,respectively.Within a tree,the growth strain variation with tree height was high but statistically insignificant while within tree variation in basic density was very small.There was no specific trend in variation in either strain or density within a tree.There was 5％-200％ difference in growth strain on opposite sides of the logs.However two strains showed a strong positive correlation.There was a moderate positive association of wood basic density and mean growth strains in logs.The variation around the periphery emphasize the need to measure strain more than one,preferably on opposite sides at the same height,on a tree to know the mean strain level for the purpose of selection of clones.
Modelling to very high strains
Bons, P. D.; Jessell, M. W.; Griera, A.; Evans, L. A.; Wilson, C. J. L.
2009-04-01
Ductile strains in shear zones often reach extreme values, resulting in typical structures, such as winged porphyroclasts and several types of shear bands. The numerical simulation of the development of such structures has so far been inhibited by the low maximum strains that numerical models can normally achieve. Typical numerical models collapse at shear strains in the order of one to three. We have implemented a number of new functionalities in the numerical platform "Elle" (Jessell et al. 2001), which significantly increases the amount of strain that can be achieved and simultaneously reduces boundary effects that become increasingly disturbing at higher strain. Constant remeshing, while maintaining the polygonal phase regions, is the first step to avoid collapse of the finite-element grid required by finite-element solvers, such as Basil (Houseman et al. 2008). The second step is to apply a grain-growth routine to the boundaries of polygons that represent phase regions. This way, the development of sharp angles is avoided. A second advantage is that phase regions may merge or become separated (boudinage). Such topological changes are normally not possible in finite element deformation codes. The third step is the use of wrapping vertical model boundaries, with which optimal and unchanging model boundaries are maintained for the application of stress or velocity boundary conditions. The fourth step is to shift the model by a random amount in the vertical direction every time step. This way, the fixed horizontal boundary conditions are applied to different material points within the model every time step. Disturbing boundary effects are thus averaged out over the whole model and not localised to e.g. top and bottom of the model. Reduction of boundary effects has the additional advantage that model can be smaller and, therefore, numerically more efficient. Owing to the combination of these existing and new functionalities it is now possible to simulate the
20 CFR 211.14 - Maximum creditable compensation.
2010-04-01
... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Maximum creditable compensation. 211.14... CREDITABLE RAILROAD COMPENSATION § 211.14 Maximum creditable compensation. Maximum creditable compensation... Employment Accounts shall notify each employer of the amount of maximum creditable compensation applicable...
49 CFR 230.24 - Maximum allowable stress.
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...
A tunable strain sensor using nanogranular metals.
Schwalb, Christian H; Grimm, Christina; Baranowski, Markus; Sachser, Roland; Porrati, Fabrizio; Reith, Heiko; Das, Pintu; Müller, Jens; Völklein, Friedemann; Kaya, Alexander; Huth, Michael
2010-01-01
This paper introduces a new methodology for the fabrication of strain-sensor elements for MEMS and NEMS applications based on the tunneling effect in nano-granular metals. The strain-sensor elements are prepared by the maskless lithography technique of focused electron-beam-induced deposition (FEBID) employing the precursor trimethylmethylcyclopentadienyl platinum [MeCpPt(Me)(3)]. We use a cantilever-based deflection technique to determine the sensitivity (gauge factor) of the sensor element. We find that its sensitivity depends on the electrical conductivity and can be continuously tuned, either by the thickness of the deposit or by electron-beam irradiation leading to a distinct maximum in the sensitivity. This maximum finds a theoretical rationale in recent advances in the understanding of electronic charge transport in nano-granular metals.
A Tunable Strain Sensor Using Nanogranular Metals
Friedemann Völklein
2010-11-01
Full Text Available This paper introduces a new methodology for the fabrication of strain-sensor elements for MEMS and NEMS applications based on the tunneling effect in nano-granular metals. The strain-sensor elements are prepared by the maskless lithography technique of focused electron-beam-induced deposition (FEBID employing the precursor trimethylmethylcyclopentadienyl platinum [MeCpPt(Me3]. We use a cantilever-based deflection technique to determine the sensitivity (gauge factor of the sensor element. We find that its sensitivity depends on the electrical conductivity and can be continuously tuned, either by the thickness of the deposit or by electron-beam irradiation leading to a distinct maximum in the sensitivity. This maximum finds a theoretical rationale in recent advances in the understanding of electronic charge transport in nano-granular metals.
A Tunable Strain Sensor Using Nanogranular Metals
Schwalb, Christian H.; Grimm, Christina; Baranowski, Markus; Sachser, Roland; Porrati, Fabrizio; Reith, Heiko; Das, Pintu; Müller, Jens; Völklein, Friedemann; Kaya, Alexander; Huth, Michael
2010-01-01
This paper introduces a new methodology for the fabrication of strain-sensor elements for MEMS and NEMS applications based on the tunneling effect in nano-granular metals. The strain-sensor elements are prepared by the maskless lithography technique of focused electron-beam-induced deposition (FEBID) employing the precursor trimethylmethylcyclopentadienyl platinum [MeCpPt(Me)3]. We use a cantilever-based deflection technique to determine the sensitivity (gauge factor) of the sensor element. We find that its sensitivity depends on the electrical conductivity and can be continuously tuned, either by the thickness of the deposit or by electron-beam irradiation leading to a distinct maximum in the sensitivity. This maximum finds a theoretical rationale in recent advances in the understanding of electronic charge transport in nano-granular metals. PMID:22163443
Theoretical Estimate of Maximum Possible Nuclear Explosion
Bethe, H. A.
1950-01-31
The maximum nuclear accident which could occur in a Na-cooled, Be moderated, Pu and power producing reactor is estimated theoretically. (T.R.H.) 2O82 Results of nuclear calculations for a variety of compositions of fast, heterogeneous, sodium-cooled, U-235-fueled, plutonium- and power-producing reactors are reported. Core compositions typical of plate-, pin-, or wire-type fuel elements and with uranium as metal, alloy, and oxide were considered. These compositions included atom ratios in the following range: U-23B to U-235 from 2 to 8; sodium to U-235 from 1.5 to 12; iron to U-235 from 5 to 18; and vanadium to U-235 from 11 to 33. Calculations were performed to determine the effect of lead and iron reflectors between the core and blanket. Both natural and depleted uranium were evaluated as the blanket fertile material. Reactors were compared on a basis of conversion ratio, specific power, and the product of both. The calculated results are in general agreement with the experimental results from fast reactor assemblies. An analysis of the effect of new cross-section values as they became available is included. (auth)
Proposed principles of maximum local entropy production.
Ross, John; Corlan, Alexandru D; Müller, Stefan C
2012-07-12
Articles have appeared that rely on the application of some form of "maximum local entropy production principle" (MEPP). This is usually an optimization principle that is supposed to compensate for the lack of structural information and measurements about complex systems, even systems as complex and as little characterized as the whole biosphere or the atmosphere of the Earth or even of less known bodies in the solar system. We select a number of claims from a few well-known papers that advocate this principle and we show that they are in error with the help of simple examples of well-known chemical and physical systems. These erroneous interpretations can be attributed to ignoring well-established and verified theoretical results such as (1) entropy does not necessarily increase in nonisolated systems, such as "local" subsystems; (2) macroscopic systems, as described by classical physics, are in general intrinsically deterministic-there are no "choices" in their evolution to be selected by using supplementary principles; (3) macroscopic deterministic systems are predictable to the extent to which their state and structure is sufficiently well-known; usually they are not sufficiently known, and probabilistic methods need to be employed for their prediction; and (4) there is no causal relationship between the thermodynamic constraints and the kinetics of reaction systems. In conclusion, any predictions based on MEPP-like principles should not be considered scientifically founded.
Maximum entropy production and plant optimization theories.
Dewar, Roderick C
2010-05-12
Plant ecologists have proposed a variety of optimization theories to explain the adaptive behaviour and evolution of plants from the perspective of natural selection ('survival of the fittest'). Optimization theories identify some objective function--such as shoot or canopy photosynthesis, or growth rate--which is maximized with respect to one or more plant functional traits. However, the link between these objective functions and individual plant fitness is seldom quantified and there remains some uncertainty about the most appropriate choice of objective function to use. Here, plants are viewed from an alternative thermodynamic perspective, as members of a wider class of non-equilibrium systems for which maximum entropy production (MEP) has been proposed as a common theoretical principle. I show how MEP unifies different plant optimization theories that have been proposed previously on the basis of ad hoc measures of individual fitness--the different objective functions of these theories emerge as examples of entropy production on different spatio-temporal scales. The proposed statistical explanation of MEP, that states of MEP are by far the most probable ones, suggests a new and extended paradigm for biological evolution--'survival of the likeliest'--which applies from biomacromolecules to ecosystems, not just to individuals.
Maximum likelihood continuity mapping for fraud detection
Hogden, J.
1997-05-01
The author describes a novel time-series analysis technique called maximum likelihood continuity mapping (MALCOM), and focuses on one application of MALCOM: detecting fraud in medical insurance claims. Given a training data set composed of typical sequences, MALCOM creates a stochastic model of sequence generation, called a continuity map (CM). A CM maximizes the probability of sequences in the training set given the model constraints, CMs can be used to estimate the likelihood of sequences not found in the training set, enabling anomaly detection and sequence prediction--important aspects of data mining. Since MALCOM can be used on sequences of categorical data (e.g., sequences of words) as well as real valued data, MALCOM is also a potential replacement for database search tools such as N-gram analysis. In a recent experiment, MALCOM was used to evaluate the likelihood of patient medical histories, where ``medical history`` is used to mean the sequence of medical procedures performed on a patient. Physicians whose patients had anomalous medical histories (according to MALCOM) were evaluated for fraud by an independent agency. Of the small sample (12 physicians) that has been evaluated, 92% have been determined fraudulent or abusive. Despite the small sample, these results are encouraging.
Maximum life spiral bevel reduction design
Savage, M.; Prasanna, M. G.; Coe, H. H.
1992-07-01
Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ratio under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed back-cone distance of the spiral bevel gear set for a specified speed ratio, shaft angle, input torque, and power. Significant parameters in the design are: the spiral angle, the pressure angle, the numbers of teeth on the pinion and gear, and the location and size of the four support bearings. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for gradient optimization. After finding the continuous optimum, a designer can analyze near optimal designs for comparison and selection. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives.
CORA - emission line fitting with Maximum Likelihood
Ness, J.-U.; Wichmann, R.
2002-07-01
The advent of pipeline-processed data both from space- and ground-based observatories often disposes of the need of full-fledged data reduction software with its associated steep learning curve. In many cases, a simple tool doing just one task, and doing it right, is all one wishes. In this spirit we introduce CORA, a line fitting tool based on the maximum likelihood technique, which has been developed for the analysis of emission line spectra with low count numbers and has successfully been used in several publications. CORA uses a rigorous application of Poisson statistics. From the assumption of Poissonian noise we derive the probability for a model of the emission line spectrum to represent the measured spectrum. The likelihood function is used as a criterion for optimizing the parameters of the theoretical spectrum and a fixed point equation is derived allowing an efficient way to obtain line fluxes. As an example we demonstrate the functionality of the program with an X-ray spectrum of Capella obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra observatory and choose the analysis of the Ne IX triplet around 13.5 Å.
Finding maximum JPEG image block code size
Lakhani, Gopal
2012-07-01
We present a study of JPEG baseline coding. It aims to determine the minimum storage needed to buffer the JPEG Huffman code bits of 8-bit image blocks. Since DC is coded separately, and the encoder represents each AC coefficient by a pair of run-length/AC coefficient level, the net problem is to perform an efficient search for the optimal run-level pair sequence. We formulate it as a two-dimensional, nonlinear, integer programming problem and solve it using a branch-and-bound based search method. We derive two types of constraints to prune the search space. The first one is given as an upper-bound for the sum of squares of AC coefficients of a block, and it is used to discard sequences that cannot represent valid DCT blocks. The second type constraints are based on some interesting properties of the Huffman code table, and these are used to prune sequences that cannot be part of optimal solutions. Our main result is that if the default JPEG compression setting is used, space of minimum of 346 bits and maximum of 433 bits is sufficient to buffer the AC code bits of 8-bit image blocks. Our implementation also pruned the search space extremely well; the first constraint reduced the initial search space of 4 nodes down to less than 2 nodes, and the second set of constraints reduced it further by 97.8%.
Maximum likelihood estimates of pairwise rearrangement distances.
Serdoz, Stuart; Egri-Nagy, Attila; Sumner, Jeremy; Holland, Barbara R; Jarvis, Peter D; Tanaka, Mark M; Francis, Andrew R
2017-06-21
Accurate estimation of evolutionary distances between taxa is important for many phylogenetic reconstruction methods. Distances can be estimated using a range of different evolutionary models, from single nucleotide polymorphisms to large-scale genome rearrangements. Corresponding corrections for genome rearrangement distances fall into 3 categories: Empirical computational studies, Bayesian/MCMC approaches, and combinatorial approaches. Here, we introduce a maximum likelihood estimator for the inversion distance between a pair of genomes, using a group-theoretic approach to modelling inversions introduced recently. This MLE functions as a corrected distance: in particular, we show that because of the way sequences of inversions interact with each other, it is quite possible for minimal distance and MLE distance to differently order the distances of two genomes from a third. The second aspect tackles the problem of accounting for the symmetries of circular arrangements. While, generally, a frame of reference is locked, and all computation made accordingly, this work incorporates the action of the dihedral group so that distance estimates are free from any a priori frame of reference. The philosophy of accounting for symmetries can be applied to any existing correction method, for which examples are offered. Copyright © 2017 Elsevier Ltd. All rights reserved.
Boedeker, Peter
2017-01-01
Hierarchical linear modeling (HLM) is a useful tool when analyzing data collected from groups. There are many decisions to be made when constructing and estimating a model in HLM including which estimation technique to use. Three of the estimation techniques available when analyzing data with HLM are maximum likelihood, restricted maximum…
How Mentor Principals Interpret the Mentoring Process Using Metaphors
Schechter, Chen; Firuz, Florit
2015-01-01
The study focused on how principal mentors perceived the mentoring process by means of the metaphors they used to represent it. Semi-structured in-depth interviews were conducted with 18 principal mentors. Findings were analysed qualitatively, generating themes as an inductive process, grounded in the various metaphors articulated by participants.…
Calibrating One's Moral Compass: How Principal Preparation Shapes School Leaders
Larsen, Donald E.; Derrington, Mary Lynne
2012-01-01
No textbook that an aspiring principal encounters in preparing for the role of school leader discusses what steps to follow when a member--or members--of the school staff challenge standards of professional judgment and moral rectitude. Instead, the most reliable guide at the principal's disposal may be the "moral compass" upon which the…
Subjective performance evaluations and reciprocity in principal-agent relations
Sebald, Alexander Christopher; Walzl, Markus
2014-01-01
. In contrast to existing models of reciprocity, we find that agents tend to sanction whenever the feedback of principals is below their subjective self-evaluations even if agents' pay-offs are independent of it. In turn, principals provide more positive feedback (relative to their actual performance assessment...
Bridging Schools and Community: Helpful Public Relations Guidelines for Principals.
Pennsylvania School Boards Association, New Cumberland.
Public relations guidelines for school principals are offered in this handbook, with an emphasis on improving student achievement and internal and external communication. Six chapters discuss the principal's public relations role, internal communication, securing and maintaining community involvement, school publications, media relations, and…
Measuring the Learning-Centered Leadership Expertise of School Principals
Goldring, Ellen; Huff, Jason; Spillane, James P.; Barnes, Carol
2009-01-01
We as a field believe that school principals can acquire new expertise by participating in principal preparation and professional development programs; however, we have few methodologies to measure leadership expertise, especially expertise that links leadership to improved student learning. In this article, we present the results of a study that…
Learning to Lead: The Professional Development Needs of Assistant Principals
Allen, James G.; Weaver, Rosa L.
2014-01-01
The purpose of this study was to investigate the professional development needs of assistant principals in the northern Kentucky region in preparation for the launch of the Northern Kentucky Assistant Principals' Network, a unique and innovative program to support their leadership development. Using the Educational Leadership Policy Standards:…
The Job Realities of Beginning and Experienced Assistant Principals
Barnett, Bruce G.; Shoho, Alan R.; Oleszewski, Ashley M.
2012-01-01
This study examined the perceptions of a cross section of new and experienced assistant principals regarding the realities of their jobs. Findings indicated that their challenges pertain to workload and task management, conflicts with adults and students, and curriculum and instruction issues. Novice and experienced assistant principals' responses…
Leadership for Successful Inclusive Schools: A Study of Principal Behaviours.
Guzman, Nadyne
1997-01-01
Describes a multiple case analysis of six elementary school principals considered to be successful leaders of inclusive schools. Each principal established an open communication system, was actively involved in developing individualized educational plans, personally conversed with parents of disabled students, collaborated with staff on inclusion…
Leadership Behaviours of Principals in Inclusive Educational Settings.
Ingram, Patreese D.
1997-01-01
A recent study explored whether the leadership behavior of principals working in inclusive schools tended to be more transformational or transactional, based on 44 teachers' responses on the Multifactor Leadership Questionnaire. Principals were judged as exhibiting more transformational than transactional behaviors. Also, teachers were more highly…
Examining Teachers' Motivation Level According to School Principals' Humor Styles
Recepoglu, Ergun; Kilinc, Ali Cagatay; Cepni, Osman
2011-01-01
The purpose of this research is to examine the motivation level of teachers according to school principals' humor styles. The humor styles survey and job motivation scale were used to gather data from 305 randomly selected teachers employed in primary schools in Karabuk. Results indicated that 141 of the teachers claimed school principal had…
The Forgotten Aspect of Communication: Principals' Listening Skills
Woods, Jerry; Shoho, Alan R.
2009-01-01
This study investigated principals' self-perceptions and teachers' perceptions of principals' listening skills. An instrument measuring perception of listening skills was developed on the basis of four listening factors: attending, empathy, response, and trustworthiness. Factor analysis confirmed the structure of the new listening instrument, and…
Principal Preservice Education for Leadership in Inclusive Schools
Lyons, Wanda
2016-01-01
Principal leadership has been identified as the key to successful implementation of inclusive education for students with disabilities. Prospective principals require knowledge, skills, and dispositions to equip them to work with key stakeholders to initiate and sustain inclusive practices within their schools. The purpose of this action research…
Principals' Perception regarding Factors Affecting the Performance of Teachers
Akram, Muhammad Javaid; Raza, Syed Ahmad; Khaleeq, Abdur Rehman; Atika, Samrana
2011-01-01
This study investigated the perception of principals on how the factors of subject mastery, teaching methodology, personal characteristics, and attitude toward students affect the performance of teachers at higher secondary level in the Punjab. All principals of higher secondary level in the Punjab were part of the population of the study. From…
20 CFR 362.10 - Principal types of claims allowable.
2010-04-01
... which the loss or damage occurred: (1) In a common or natural disaster; (2) When the property was... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Principal types of claims allowable. 362.10... PROCEDURES EMPLOYEES' PERSONAL PROPERTY CLAIMS § 362.10 Principal types of claims allowable. (a) In...
Examining Teachers' Motivation Level According to School Principals' Humor Styles
Recepoglu, Ergun; Kilinc, Ali Cagatay; Cepni, Osman
2011-01-01
The purpose of this research is to examine the motivation level of teachers according to school principals' humor styles. The humor styles survey and job motivation scale were used to gather data from 305 randomly selected teachers employed in primary schools in Karabuk. Results indicated that 141 of the teachers claimed school principal had…
40 CFR 264.342 - Principal organic hazardous constituents (POHCs).
2010-07-01
... (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE...) Principal Organic Hazardous Constituents (POHCs) in the waste feed must be treated to the extent required by... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Principal organic hazardous...
High School Principals as Leaders: Styles and Sources of Power
Brinia, Vasiliki; Papantoniou, Eva
2016-01-01
Purpose: The purpose of this paper is to present the characteristics of leadership (style adopted, sources of power exercised and factors affecting leadership) of high school principals in Greece. Design/Methodology/Approach: In total, 235 school principals were surveyed using questionnaires. These questionnaires assessed how often they adopted…
Principals' Management Behavior, Personality Types and Physiological Stress.
Cooper, Bruce S.; And Others
1988-01-01
Data from portable heart-rate monitors and work diaries were used to relate Mintzberg's "nature of managerial work" to physiological stress in small number of working principals over three complete work days. Principals found to be working under extreme stress for long hours, and certain activities were more stressful than others.…
Instructional Leadership Potential among School Principals in Pakistan
Niqab, Muhammad; Sharma, Sailesh; Wei, Leong Mei; Maulod, Shafinaz Bt A.
2014-01-01
This study highlights the pivotal role of the school principal in relation to organizational commitment and expected student outcomes in schools in Pakistan. By critically examining the available literature, and by evaluating relevant data, this study will draw attention to how successful principals manage their schools, by providing an…
The Job Realities of Beginning and Experienced Assistant Principals
Barnett, Bruce G.; Shoho, Alan R.; Oleszewski, Ashley M.
2012-01-01
This study examined the perceptions of a cross section of new and experienced assistant principals regarding the realities of their jobs. Findings indicated that their challenges pertain to workload and task management, conflicts with adults and students, and curriculum and instruction issues. Novice and experienced assistant principals' responses…
A Phenomenological Narrative Study: Elementary Charter School Principals' Managerial Roles
Cetinkaya, Ahmet
2016-01-01
This study was a phenomenological narrative research investigating the managerial roles of elementary charter school principals. Managerial leadership practices were investigated under three categories personnel management, student management, and finance management. Elementary charter school principals provided positive feedback for having small…
Principals' Leadership Styles and ESL Teachers' Job Satisfaction
Jackson, K. A'jaydin
2013-01-01
The purpose of this research study was to examine principals' leadership styles and how and what extent it impacted teachers' job satisfaction. Principals' leadership styles were examined by middle and high school teachers' perceptions. This study drew from 10 middle and 10 high schools in a large school district located in Texas. Participants…
Principals' Perceptions of Needs in Hispanic Special Education
Roberts, Maria B.; Guerra, Federico, Jr.
2017-01-01
This mixed methods study used a survey by Frost and Kersten to answer the following questions: (a) Do principals of predominantly Hispanic schools perceive themselves as having adequate knowledge in special education? (b) Which areas are these principals most involved in with special education teachers? (c) What suggestions do these principals…
Principals' Perceptions of Their Knowledge in Special Education
Roberts, Maria Banda; Guerra, Federico R., Jr.
2017-01-01
With the "Every Student Succeeds Act" continuing to legislate accountability for special education and Hispanic students, the appropriate content in principal preparation programs relevant to successful leadership of special education programs is vital. This mixed methods study analyzed the survey responses of 84 principals in South…
From Redistribution to Recognition: How School Principals Perceive Social Justice
Wang, Fei
2016-01-01
Where there are people, there is social in/justice. Using Nancy Fraser's framework, this qualitative research examines how school principals perceive social justice in schools. Twenty-one elementary and secondary school principals were interviewed in the Greater Toronto Area. The study provides some empirical evidence on the ways social…
Dress Codes in the Public Schools: Principals, Policies, and Precepts.
DeMitchell, Todd A.; Fossey, Richard; Cobb, Casey
2000-01-01
Responses from 157 principals (65 percent of a national sample) showed strong support for dress codes. Research focuses on the perception of school principals regarding dress codes, analyzes dress codes for common features, and proposes a constitutional standard of review for contested dress codes. (58 footnotes) (MLF)
Leading with Heart: Urban Elementary Principals as Advocates for Students
Rodriguez, Mariela A.; Murakami-Ramalho, Elizabeth; Ruff, William G.
2009-01-01
Principals in urban settings serve elementary schools often densely populated with highly mobile, ethnically diverse, and economically disadvantaged students. Due to the changing landscape of increasing accountability issues required by the "No Child Left Behind Act (NCLB)" (2001), principals must adjust the mission of the school community to meet…