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Sample records for principal skeleton algorithm

  1. Development and evaluation of an articulated registration algorithm for human skeleton registration

    NASA Astrophysics Data System (ADS)

    Yip, Stephen; Perk, Timothy; Jeraj, Robert

    2014-03-01

    Accurate registration over multiple scans is necessary to assess treatment response of bone diseases (e.g. metastatic bone lesions). This study aimed to develop and evaluate an articulated registration algorithm for the whole-body skeleton registration in human patients. In articulated registration, whole-body skeletons are registered by auto-segmenting into individual bones using atlas-based segmentation, and then rigidly aligning them. Sixteen patients (weight = 80-117 kg, height = 168-191 cm) with advanced prostate cancer underwent the pre- and mid-treatment PET/CT scans over a course of cancer therapy. Skeletons were extracted from the CT images by thresholding (HU>150). Skeletons were registered using the articulated, rigid, and deformable registration algorithms to account for position and postural variability between scans. The inter-observers agreement in the atlas creation, the agreement between the manually and atlas-based segmented bones, and the registration performances of all three registration algorithms were all assessed using the Dice similarity index—DSIobserved, DSIatlas, and DSIregister. Hausdorff distance (dHausdorff) of the registered skeletons was also used for registration evaluation. Nearly negligible inter-observers variability was found in the bone atlases creation as the DSIobserver was 96 ± 2%. Atlas-based and manual segmented bones were in excellent agreement with DSIatlas of 90 ± 3%. Articulated (DSIregsiter = 75 ± 2%, dHausdorff = 0.37 ± 0.08 cm) and deformable registration algorithms (DSIregister = 77 ± 3%, dHausdorff = 0.34 ± 0.08 cm) considerably outperformed the rigid registration algorithm (DSIregsiter = 59 ± 9%, dHausdorff = 0.69 ± 0.20 cm) in the skeleton registration as the rigid registration algorithm failed to capture the skeleton flexibility in the joints. Despite superior skeleton registration performance, deformable registration algorithm failed to preserve the local rigidity of bones as over 60% of the

  2. Development and evaluation of an articulated registration algorithm for human skeleton registration.

    PubMed

    Yip, Stephen; Perk, Timothy; Jeraj, Robert

    2014-03-21

    Accurate registration over multiple scans is necessary to assess treatment response of bone diseases (e.g. metastatic bone lesions). This study aimed to develop and evaluate an articulated registration algorithm for the whole-body skeleton registration in human patients. In articulated registration, whole-body skeletons are registered by auto-segmenting into individual bones using atlas-based segmentation, and then rigidly aligning them. Sixteen patients (weight = 80-117 kg, height = 168-191 cm) with advanced prostate cancer underwent the pre- and mid-treatment PET/CT scans over a course of cancer therapy. Skeletons were extracted from the CT images by thresholding (HU>150). Skeletons were registered using the articulated, rigid, and deformable registration algorithms to account for position and postural variability between scans. The inter-observers agreement in the atlas creation, the agreement between the manually and atlas-based segmented bones, and the registration performances of all three registration algorithms were all assessed using the Dice similarity index-DSIobserved, DSIatlas, and DSIregister. Hausdorff distance (dHausdorff) of the registered skeletons was also used for registration evaluation. Nearly negligible inter-observers variability was found in the bone atlases creation as the DSIobserver was 96 ± 2%. Atlas-based and manual segmented bones were in excellent agreement with DSIatlas of 90 ± 3%. Articulated (DSIregsiter = 75 ± 2%, dHausdorff = 0.37 ± 0.08 cm) and deformable registration algorithms (DSIregister = 77 ± 3%, dHausdorff = 0.34 ± 0.08 cm) considerably outperformed the rigid registration algorithm (DSIregsiter = 59 ± 9%, dHausdorff = 0.69 ± 0.20 cm) in the skeleton registration as the rigid registration algorithm failed to capture the skeleton flexibility in the joints. Despite superior skeleton registration performance, deformable registration algorithm failed to preserve the local rigidity of bones as over 60% of the skeletons

  3. Fuzzy Genetic Algorithm Based on Principal Operation and Inequity Degree

    NASA Astrophysics Data System (ADS)

    Li, Fachao; Jin, Chenxia

    In this paper, starting from the structure of fuzzy information, by distinguishing principal indexes and assistant indexes, give comparison of fuzzy information on synthesizing effect and operation of fuzzy optimization on principal indexes transformation, further, propose axiom system of fuzzy inequity degree from essence of constraint, and give an instructive metric method; Then, combining genetic algorithm, give fuzzy optimization methods based on principal operation and inequity degree (denoted by BPO&ID-FGA, for short); Finally, consider its convergence using Markov chain theory and analyze its performance through an example. All these indicate, BPO&ID-FGA can not only effectively merge decision consciousness into the optimization process, but possess better global convergence, so it can be applied to many fuzzy optimization problems.

  4. Managing Algorithmic Skeleton Nesting Requirements in Realistic Image Processing Applications: The Case of the SKiPPER-II Parallel Programming Environment's Operating Model

    NASA Astrophysics Data System (ADS)

    Coudarcher, Rémi; Duculty, Florent; Serot, Jocelyn; Jurie, Frédéric; Derutin, Jean-Pierre; Dhome, Michel

    2005-12-01

    SKiPPER is a SKeleton-based Parallel Programming EnviRonment being developed since 1996 and running at LASMEA Laboratory, the Blaise-Pascal University, France. The main goal of the project was to demonstrate the applicability of skeleton-based parallel programming techniques to the fast prototyping of reactive vision applications. This paper deals with the special features embedded in the latest version of the project: algorithmic skeleton nesting capabilities and a fully dynamic operating model. Throughout the case study of a complete and realistic image processing application, in which we have pointed out the requirement for skeleton nesting, we are presenting the operating model of this feature. The work described here is one of the few reported experiments showing the application of skeleton nesting facilities for the parallelisation of a realistic application, especially in the area of image processing. The image processing application we have chosen is a 3D face-tracking algorithm from appearance.

  5. Axial Skeleton

    MedlinePlus

    ... Site-specific Modules Resources Archived Modules Updates Axial Skeleton (80 bones) Skull (28) Cranial Bones Parietal (2) ... Sternum (1) Ribs (24) « Previous (Divisions of the Skeleton) Next (Appendicular Skeleton (126 bones)) » Contact Us | Privacy ...

  6. [Skeleton extractions and applications].

    SciTech Connect

    Quadros, William Roshan

    2010-05-01

    This paper focuses on the extraction of skeletons of CAD models and its applications in finite element (FE) mesh generation. The term 'skeleton of a CAD model' can be visualized as analogous to the 'skeleton of a human body'. The skeletal representations covered in this paper include medial axis transform (MAT), Voronoi diagram (VD), chordal axis transform (CAT), mid surface, digital skeletons, and disconnected skeletons. In the literature, the properties of a skeleton have been utilized in developing various algorithms for extracting skeletons. Three main approaches include: (1) the bisection method where the skeleton exists at equidistant from at least two points on boundary, (2) the grassfire propagation method in which the skeleton exists where the opposing fronts meet, and (3) the duality method where the skeleton is a dual of the object. In the last decade, the author has applied different skeletal representations in all-quad meshing, hex meshing, mid-surface meshing, mesh size function generation, defeaturing, and decomposition. A brief discussion on the related work from other researchers in the area of tri meshing, tet meshing, and anisotropic meshing is also included. This paper concludes by summarizing the strengths and weaknesses of the skeleton-based approaches in solving various geometry-centered problems in FE mesh generation. The skeletons have proved to be a great shape abstraction tool in analyzing the geometric complexity of CAD models as they are symmetric, simpler (reduced dimension), and provide local thickness information. However, skeletons generally require some cleanup, and stability and sensitivity of the skeletons should be controlled during extraction. Also, selecting a suitable application-specific skeleton and a computationally efficient method of extraction is critical.

  7. Fast and stable algorithms for computing the principal square root of a complex matrix

    NASA Technical Reports Server (NTRS)

    Shieh, Leang S.; Lian, Sui R.; Mcinnis, Bayliss C.

    1987-01-01

    This note presents recursive algorithms that are rapidly convergent and more stable for finding the principal square root of a complex matrix. Also, the developed algorithms are utilized to derive the fast and stable matrix sign algorithms which are useful in developing applications to control system problems.

  8. A unified self-stabilizing neural network algorithm for principal and minor components extraction.

    PubMed

    Kong, Xiangyu; Hu, Changhua; Ma, Hongguang; Han, Chongzhao

    2012-02-01

    Recently, many unified learning algorithms have been developed for principal component analysis and minor component analysis. These unified algorithms can be used to extract principal components and, if altered simply by the sign, can also serve as a minor component extractor. This is of practical significance in the implementations of algorithms. This paper proposes a unified self-stabilizing neural network learning algorithm for principal and minor components extraction, and studies the stability of the proposed unified algorithm via the fixed-point analysis method. The proposed unified self-stabilizing algorithm for principal and minor components extraction is extended for tracking the principal subspace (PS) and minor subspace (MS). The averaging differential equation and the energy function associated with the unified algorithm for tracking PS and MS are given. It is shown that the averaging differential equation will globally asymptotically converge to an invariance set, and the corresponding energy function exhibit a unique global minimum attained if and only if its state matrices span the PS or MS of the autocorrelation matrix of a vector data stream. It is concluded that the proposed unified algorithm for tracking PS and MS can efficiently track an orthonormal basis of the PS or MS. Simulations are carried out to further illustrate the theoretical results achieved.

  9. Appendicular Skeleton

    MedlinePlus

    ... Site-specific Modules Resources Archived Modules Updates Appendicular Skeleton (126 bones) Pectoral girdles Clavicle (2) Scapula (2) ... Tarsals (14) Metatarsals (10) Phalanges (28) « Previous (Axial Skeleton (80 bones)) Next (Articulations) » Contact Us | Privacy Policy | ...

  10. Time-oriented hierarchical method for computation of principal components using subspace learning algorithm.

    PubMed

    Jankovic, Marko; Ogawa, Hidemitsu

    2004-10-01

    Principal Component Analysis (PCA) and Principal Subspace Analysis (PSA) are classic techniques in statistical data analysis, feature extraction and data compression. Given a set of multivariate measurements, PCA and PSA provide a smaller set of "basis vectors" with less redundancy, and a subspace spanned by them, respectively. Artificial neurons and neural networks have been shown to perform PSA and PCA when gradient ascent (descent) learning rules are used, which is related to the constrained maximization (minimization) of statistical objective functions. Due to their low complexity, such algorithms and their implementation in neural networks are potentially useful in cases of tracking slow changes of correlations in the input data or in updating eigenvectors with new samples. In this paper we propose PCA learning algorithm that is fully homogeneous with respect to neurons. The algorithm is obtained by modification of one of the most famous PSA learning algorithms--Subspace Learning Algorithm (SLA). Modification of the algorithm is based on Time-Oriented Hierarchical Method (TOHM). The method uses two distinct time scales. On a faster time scale PSA algorithm is responsible for the "behavior" of all output neurons. On a slower scale, output neurons will compete for fulfillment of their "own interests". On this scale, basis vectors in the principal subspace are rotated toward the principal eigenvectors. At the end of the paper it will be briefly analyzed how (or why) time-oriented hierarchical method can be used for transformation of any of the existing neural network PSA method, into PCA method.

  11. Time-oriented hierarchical method for computation of principal components using subspace learning algorithm.

    PubMed

    Jankovic, Marko; Ogawa, Hidemitsu

    2004-10-01

    Principal Component Analysis (PCA) and Principal Subspace Analysis (PSA) are classic techniques in statistical data analysis, feature extraction and data compression. Given a set of multivariate measurements, PCA and PSA provide a smaller set of "basis vectors" with less redundancy, and a subspace spanned by them, respectively. Artificial neurons and neural networks have been shown to perform PSA and PCA when gradient ascent (descent) learning rules are used, which is related to the constrained maximization (minimization) of statistical objective functions. Due to their low complexity, such algorithms and their implementation in neural networks are potentially useful in cases of tracking slow changes of correlations in the input data or in updating eigenvectors with new samples. In this paper we propose PCA learning algorithm that is fully homogeneous with respect to neurons. The algorithm is obtained by modification of one of the most famous PSA learning algorithms--Subspace Learning Algorithm (SLA). Modification of the algorithm is based on Time-Oriented Hierarchical Method (TOHM). The method uses two distinct time scales. On a faster time scale PSA algorithm is responsible for the "behavior" of all output neurons. On a slower scale, output neurons will compete for fulfillment of their "own interests". On this scale, basis vectors in the principal subspace are rotated toward the principal eigenvectors. At the end of the paper it will be briefly analyzed how (or why) time-oriented hierarchical method can be used for transformation of any of the existing neural network PSA method, into PCA method. PMID:15593379

  12. Image segmentation and registration algorithm to collect thoracic skeleton semilandmarks for characterization of age and sex-based thoracic morphology variation.

    PubMed

    Weaver, Ashley A; Nguyen, Callistus M; Schoell, Samantha L; Maldjian, Joseph A; Stitzel, Joel D

    2015-12-01

    Thoracic anthropometry variations with age and sex have been reported and likely relate to thoracic injury risk and outcome. The objective of this study was to collect a large volume of homologous semilandmark data from the thoracic skeleton for the purpose of quantifying thoracic morphology variations for males and females of ages 0-100 years. A semi-automated image segmentation and registration algorithm was applied to collect homologous thoracic skeleton semilandmarks from 343 normal computed tomography (CT) scans. Rigid, affine, and symmetric diffeomorphic transformations were used to register semilandmarks from an atlas to homologous locations in the subject-specific coordinate system. Homologous semilandmarks were successfully collected from 92% (7077) of the ribs and 100% (187) of the sternums included in the study. Between 2700 and 11,000 semilandmarks were collected from each rib and sternum and over 55 million total semilandmarks were collected from all subjects. The extensive landmark data collected more fully characterizes thoracic skeleton morphology across ages and sexes. Characterization of thoracic morphology with age and sex may help explain variations in thoracic injury risk and has important implications for vulnerable populations such as pediatrics and the elderly.

  13. Functional Principal Component Analysis and Randomized Sparse Clustering Algorithm for Medical Image Analysis.

    PubMed

    Lin, Nan; Jiang, Junhai; Guo, Shicheng; Xiong, Momiao

    2015-01-01

    Due to the advancement in sensor technology, the growing large medical image data have the ability to visualize the anatomical changes in biological tissues. As a consequence, the medical images have the potential to enhance the diagnosis of disease, the prediction of clinical outcomes and the characterization of disease progression. But in the meantime, the growing data dimensions pose great methodological and computational challenges for the representation and selection of features in image cluster analysis. To address these challenges, we first extend the functional principal component analysis (FPCA) from one dimension to two dimensions to fully capture the space variation of image the signals. The image signals contain a large number of redundant features which provide no additional information for clustering analysis. The widely used methods for removing the irrelevant features are sparse clustering algorithms using a lasso-type penalty to select the features. However, the accuracy of clustering using a lasso-type penalty depends on the selection of the penalty parameters and the threshold value. In practice, they are difficult to determine. Recently, randomized algorithms have received a great deal of attentions in big data analysis. This paper presents a randomized algorithm for accurate feature selection in image clustering analysis. The proposed method is applied to both the liver and kidney cancer histology image data from the TCGA database. The results demonstrate that the randomized feature selection method coupled with functional principal component analysis substantially outperforms the current sparse clustering algorithms in image cluster analysis. PMID:26196383

  14. Functional Principal Component Analysis and Randomized Sparse Clustering Algorithm for Medical Image Analysis

    PubMed Central

    Lin, Nan; Jiang, Junhai; Guo, Shicheng; Xiong, Momiao

    2015-01-01

    Due to the advancement in sensor technology, the growing large medical image data have the ability to visualize the anatomical changes in biological tissues. As a consequence, the medical images have the potential to enhance the diagnosis of disease, the prediction of clinical outcomes and the characterization of disease progression. But in the meantime, the growing data dimensions pose great methodological and computational challenges for the representation and selection of features in image cluster analysis. To address these challenges, we first extend the functional principal component analysis (FPCA) from one dimension to two dimensions to fully capture the space variation of image the signals. The image signals contain a large number of redundant features which provide no additional information for clustering analysis. The widely used methods for removing the irrelevant features are sparse clustering algorithms using a lasso-type penalty to select the features. However, the accuracy of clustering using a lasso-type penalty depends on the selection of the penalty parameters and the threshold value. In practice, they are difficult to determine. Recently, randomized algorithms have received a great deal of attentions in big data analysis. This paper presents a randomized algorithm for accurate feature selection in image clustering analysis. The proposed method is applied to both the liver and kidney cancer histology image data from the TCGA database. The results demonstrate that the randomized feature selection method coupled with functional principal component analysis substantially outperforms the current sparse clustering algorithms in image cluster analysis. PMID:26196383

  15. Orbiter's Skeleton

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The structure of NASA's Mars Reconnaissance Orbiter spacecraft is constructed from composite panels of carbon layers over aluminum honeycomb, lightweight yet strong. This forms a basic structure or skeleton on which the instruments, electronics, propulsion and power systems can be mounted. The propellant tank is contained in the center of the orbiter's structure. This photo was taken at Lockheed Martin Space Systems, Denver, during construction of the spacecraft.

  16. Intensity-based skeletonization of CryoEM gray-scale images using a true segmentation-free algorithm.

    PubMed

    Al Nasr, Kamal; Liu, Chunmei; Rwebangira, Mugizi; Burge, Legand; He, Jing

    2013-01-01

    Cryo-electron microscopy is an experimental technique that is able to produce 3D gray-scale images of protein molecules. In contrast to other experimental techniques, cryo-electron microscopy is capable of visualizing large molecular complexes such as viruses and ribosomes. At medium resolution, the positions of the atoms are not visible and the process cannot proceed. The medium-resolution images produced by cryo-electron microscopy are used to derive the atomic structure of the proteins in de novo modeling. The skeletons of the 3D gray-scale images are used to interpret important information that is helpful in de novo modeling. Unfortunately, not all features of the image can be captured using a single segmentation. In this paper, we present a segmentation-free approach to extract the gray-scale curve-like skeletons. The approach relies on a novel representation of the 3D image, where the image is modeled as a graph and a set of volume trees. A test containing 36 synthesized maps and one authentic map shows that our approach can improve the performance of the two tested tools used in de novo modeling. The improvements were 62 and 13 percent for Gorgon and DP-TOSS, respectively.

  17. Using the robust principal component analysis algorithm to remove RF spike artifacts from MR images

    PubMed Central

    Atkinson, David; Nagy, Zoltan; Chan, Rachel W.; Josephs, Oliver; Lythgoe, Mark F.; Ordidge, Roger J.; Thomas, David L.

    2015-01-01

    Purpose Brief bursts of RF noise during MR data acquisition (“k‐space spikes”) cause disruptive image artifacts, manifesting as stripes overlaid on the image. RF noise is often related to hardware problems, including vibrations during gradient‐heavy sequences, such as diffusion‐weighted imaging. In this study, we present an application of the Robust Principal Component Analysis (RPCA) algorithm to remove spike noise from k‐space. Methods: Corrupted k‐space matrices were decomposed into their low‐rank and sparse components using the RPCA algorithm, such that spikes were contained within the sparse component and artifact‐free k‐space data remained in the low‐rank component. Automated center refilling was applied to keep the peaked central cluster of k‐space from misclassification in the sparse component. Results: This algorithm was demonstrated to effectively remove k‐space spikes from four data types under conditions generating spikes: (i) mouse heart T1 mapping, (ii) mouse heart cine imaging, (iii) human kidney diffusion tensor imaging (DTI) data, and (iv) human brain DTI data. Myocardial T1 values changed by 86.1 ± 171 ms following despiking, and fractional anisotropy values were recovered following despiking of DTI data. Conclusion: The RPCA despiking algorithm will be a valuable postprocessing method for retrospectively removing stripe artifacts without affecting the underlying signal of interest. Magn Reson Med 75:2517–2525, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. PMID:26193125

  18. Nonlinear fitness space structure adaptation and principal component analysis in genetic algorithms: an application to x-ray reflectivity analysis

    NASA Astrophysics Data System (ADS)

    Tiilikainen, J.; Tilli, J.-M.; Bosund, V.; Mattila, M.; Hakkarainen, T.; Airaksinen, V.-M.; Lipsanen, H.

    2007-01-01

    Two novel genetic algorithms implementing principal component analysis and an adaptive nonlinear fitness-space-structure technique are presented and compared with conventional algorithms in x-ray reflectivity analysis. Principal component analysis based on Hessian or interparameter covariance matrices is used to rotate a coordinate frame. The nonlinear adaptation applies nonlinear estimates to reshape the probability distribution of the trial parameters. The simulated x-ray reflectivity of a realistic model of a periodic nanolaminate structure was used as a test case for the fitting algorithms. The novel methods had significantly faster convergence and less stagnation than conventional non-adaptive genetic algorithms. The covariance approach needs no additional curve calculations compared with conventional methods, and it had better convergence properties than the computationally expensive Hessian approach. These new algorithms can also be applied to other fitting problems where tight interparameter dependence is present.

  19. Wavelet-based approach to character skeleton.

    PubMed

    You, Xinge; Tang, Yuan Yan

    2007-05-01

    Character skeleton plays a significant role in character recognition. The strokes of a character may consist of two regions, i.e., singular and regular regions. The intersections and junctions of the strokes belong to singular region, while the straight and smooth parts of the strokes are categorized to regular region. Therefore, a skeletonization method requires two different processes to treat the skeletons in theses two different regions. All traditional skeletonization algorithms are based on the symmetry analysis technique. The major problems of these methods are as follows. 1) The computation of the primary skeleton in the regular region is indirect, so that its implementation is sophisticated and costly. 2) The extracted skeleton cannot be exactly located on the central line of the stroke. 3) The captured skeleton in the singular region may be distorted by artifacts and branches. To overcome these problems, a novel scheme of extracting the skeleton of character based on wavelet transform is presented in this paper. This scheme consists of two main steps, namely: a) extraction of primary skeleton in the regular region and b) amendment processing of the primary skeletons and connection of them in the singular region. A direct technique is used in the first step, where a new wavelet-based symmetry analysis is developed for finding the central line of the stroke directly. A novel method called smooth interpolation is designed in the second step, where a smooth operation is applied to the primary skeleton, and, thereafter, the interpolation compensation technique is proposed to link the primary skeleton, so that the skeleton in the singular region can be produced. Experiments are conducted and positive results are achieved, which show that the proposed skeletonization scheme is applicable to not only binary image but also gray-level image, and the skeleton is robust against noise and affine transform.

  20. GA-fisher: A new LDA-based face recognition algorithm with selection of principal components.

    PubMed

    Zheng, Wei-Shi; Lai, Jian-Huang; Yuen, Pong C

    2005-10-01

    This paper addresses the dimension reduction problem in Fisherface for face recognition. When the number of training samples is less than the image dimension (total number of pixels), the within-class scatter matrix (Sw) in Linear Discriminant Analysis (LDA) is singular, and Principal Component Analysis (PCA) is suggested to employ in Fisherface for dimension reduction of Sw so that it becomes nonsingular. The popular method is to select the largest nonzero eigenvalues and the corresponding eigenvectors for LDA. To attenuate the illumination effect, some researchers suggested removing the three eigenvectors with the largest eigenvalues and the performance is improved. However, as far as we know, there is no systematic way to determine which eigenvalues should be used. Along this line, this paper proposes a theorem to interpret why PCA can be used in LDA and an automatic and systematic method to select the eigenvectors to be used in LDA using a Genetic Algorithm (GA). A GA-PCA is then developed. It is found that some small eigenvectors should also be used as part of the basis for dimension reduction. Using the GA-PCA to reduce the dimension, a GA-Fisher method is designed and developed. Comparing with the traditional Fisherface method, the proposed GA-Fisher offers two additional advantages. First, optimal bases for dimensionality reduction are derived from GA-PCA. Second, the computational efficiency of LDA is improved by adding a whitening procedure after dimension reduction. The Face Recognition Technology (FERET) and Carnegie Mellon University Pose, Illumination, and Expression (CMU PIE) databases are used for evaluation. Experimental results show that almost 5 % improvement compared with Fisherface can be obtained, and the results are encouraging.

  1. Coral Skeletons Defend against Ultraviolet Radiation

    PubMed Central

    Reef, Ruth; Kaniewska, Paulina; Hoegh-Guldberg, Ove

    2009-01-01

    Background Many coral reef organisms are photosynthetic or have evolved in tight symbiosis with photosynthetic symbionts. As such, the tissues of reef organisms are often exposed to intense solar radiation in clear tropical waters and have adapted to trap and harness photosynthetically active radiation (PAR). High levels of ultraviolet radiation (UVR) associated with sunlight, however, represent a potential problem in terms of tissue damage. Methodology/Principal Findings By measuring UVR and PAR reflectance from intact and ground bare coral skeletons we show that the property of calcium carbonate skeletons to absorb downwelling UVR to a significant extent, while reflecting PAR back to the overlying tissue, has biological advantages. We placed cnidarians on top of bare skeletons and a UVR reflective substrate and showed that under ambient UVR levels, UVR transmitted through the tissues of cnidarians placed on top of bare skeletons were four times lower compared to their counterparts placed on a UVR reflective white substrate. In accordance with the lower levels of UVR measured in cnidarians on top of coral skeletons, a similar drop in UVR damage to their DNA was detected. The skeletons emitted absorbed UVR as yellow fluorescence, which allows for safe dissipation of the otherwise harmful radiation. Conclusions/Significance Our study presents a novel defensive role for coral skeletons and reveals that the strong UVR absorbance by the skeleton can contribute to the ability of corals, and potentially other calcifiers, to thrive under UVR levels that are detrimental to most marine life. PMID:19946361

  2. Analysis of the principal component algorithm in phase-shifting interferometry.

    PubMed

    Vargas, J; Quiroga, J Antonio; Belenguer, T

    2011-06-15

    We recently presented a new asynchronous demodulation method for phase-sampling interferometry. The method is based in the principal component analysis (PCA) technique. In the former work, the PCA method was derived heuristically. In this work, we present an in-depth analysis of the PCA demodulation method.

  3. Experimental assessment of an automatic breast density classification algorithm based on principal component analysis applied to histogram data

    NASA Astrophysics Data System (ADS)

    Angulo, Antonio; Ferrer, Jose; Pinto, Joseph; Lavarello, Roberto; Guerrero, Jorge; Castaneda, Benjamín.

    2015-01-01

    Breast parenchymal density is considered a strong indicator of cancer risk. However, measures of breast density are often qualitative and require the subjective judgment of radiologists. This work proposes a supervised algorithm to automatically assign a BI-RADS breast density score to a digital mammogram. The algorithm applies principal component analysis to the histograms of a training dataset of digital mammograms to create four different spaces, one for each BI-RADS category. Scoring is achieved by projecting the histogram of the image to be classified onto the four spaces and assigning it to the closest class. In order to validate the algorithm, a training set of 86 images and a separate testing database of 964 images were built. All mammograms were acquired in the craniocaudal view from female patients without any visible pathology. Eight experienced radiologists categorized the mammograms according to a BIRADS score and the mode of their evaluations was considered as ground truth. Results show better agreement between the algorithm and ground truth for the training set (kappa=0.74) than for the test set (kappa=0.44) which suggests the method may be used for BI-RADS classification but a better training is required.

  4. Histology of the heterostracan dermal skeleton: Insight into the origin of the vertebrate mineralised skeleton

    PubMed Central

    Marquart, Chloe L.

    2015-01-01

    ABSTRACT Living vertebrates are divided into those that possess a fully formed and fully mineralised skeleton (gnathostomes) versus those that possess only unmineralised cartilaginous rudiments (cyclostomes). As such, extinct phylogenetic intermediates of these living lineages afford unique insights into the evolutionary assembly of the vertebrate mineralised skeleton and its canonical tissue types. Extinct jawless and jawed fishes assigned to the gnathostome stem evidence the piecemeal assembly of skeletal systems, revealing that the dermal skeleton is the earliest manifestation of a homologous mineralised skeleton. Yet the nature of the primitive dermal skeleton, itself, is poorly understood. This is principally because previous histological studies of early vertebrates lacked a phylogenetic framework required to derive evolutionary hypotheses. Nowhere is this more apparent than within Heterostraci, a diverse clade of primitive jawless vertebrates. To this end, we surveyed the dermal skeletal histology of heterostracans, inferred the plesiomorphic heterostracan skeleton and, through histological comparison to other skeletonising vertebrate clades, deduced the ancestral nature of the vertebrate dermal skeleton. Heterostracans primitively possess a four‐layered skeleton, comprising a superficial layer of odontodes composed of dentine and enameloid; a compact layer of acellular parallel‐fibred bone containing a network of vascular canals that supply the pulp canals (L1); a trabecular layer consisting of intersecting radial walls composed of acellular parallel‐fibred bone, showing osteon‐like development (L2); and a basal layer of isopedin (L3). A three layered skeleton, equivalent to the superficial layer L2 and L3 and composed of enameloid, dentine and acellular bone, is possessed by the ancestor of heterostracans + jawed vertebrates. We conclude that an osteogenic component is plesiomorphic with respect to the vertebrate dermal skeleton. Consequently, we

  5. Histology of the heterostracan dermal skeleton: Insight into the origin of the vertebrate mineralised skeleton.

    PubMed

    Keating, Joseph N; Marquart, Chloe L; Donoghue, Philip C J

    2015-06-01

    Living vertebrates are divided into those that possess a fully formed and fully mineralised skeleton (gnathostomes) versus those that possess only unmineralised cartilaginous rudiments (cyclostomes). As such, extinct phylogenetic intermediates of these living lineages afford unique insights into the evolutionary assembly of the vertebrate mineralised skeleton and its canonical tissue types. Extinct jawless and jawed fishes assigned to the gnathostome stem evidence the piecemeal assembly of skeletal systems, revealing that the dermal skeleton is the earliest manifestation of a homologous mineralised skeleton. Yet the nature of the primitive dermal skeleton, itself, is poorly understood. This is principally because previous histological studies of early vertebrates lacked a phylogenetic framework required to derive evolutionary hypotheses. Nowhere is this more apparent than within Heterostraci, a diverse clade of primitive jawless vertebrates. To this end, we surveyed the dermal skeletal histology of heterostracans, inferred the plesiomorphic heterostracan skeleton and, through histological comparison to other skeletonising vertebrate clades, deduced the ancestral nature of the vertebrate dermal skeleton. Heterostracans primitively possess a four-layered skeleton, comprising a superficial layer of odontodes composed of dentine and enameloid; a compact layer of acellular parallel-fibred bone containing a network of vascular canals that supply the pulp canals (L1); a trabecular layer consisting of intersecting radial walls composed of acellular parallel-fibred bone, showing osteon-like development (L2); and a basal layer of isopedin (L3). A three layered skeleton, equivalent to the superficial layer L2 and L3 and composed of enameloid, dentine and acellular bone, is possessed by the ancestor of heterostracans + jawed vertebrates. We conclude that an osteogenic component is plesiomorphic with respect to the vertebrate dermal skeleton. Consequently, we interpret the

  6. A hybrid color space for skin detection using genetic algorithm heuristic search and principal component analysis technique.

    PubMed

    Maktabdar Oghaz, Mahdi; Maarof, Mohd Aizaini; Zainal, Anazida; Rohani, Mohd Foad; Yaghoubyan, S Hadi

    2015-01-01

    Color is one of the most prominent features of an image and used in many skin and face detection applications. Color space transformation is widely used by researchers to improve face and skin detection performance. Despite the substantial research efforts in this area, choosing a proper color space in terms of skin and face classification performance which can address issues like illumination variations, various camera characteristics and diversity in skin color tones has remained an open issue. This research proposes a new three-dimensional hybrid color space termed SKN by employing the Genetic Algorithm heuristic and Principal Component Analysis to find the optimal representation of human skin color in over seventeen existing color spaces. Genetic Algorithm heuristic is used to find the optimal color component combination setup in terms of skin detection accuracy while the Principal Component Analysis projects the optimal Genetic Algorithm solution to a less complex dimension. Pixel wise skin detection was used to evaluate the performance of the proposed color space. We have employed four classifiers including Random Forest, Naïve Bayes, Support Vector Machine and Multilayer Perceptron in order to generate the human skin color predictive model. The proposed color space was compared to some existing color spaces and shows superior results in terms of pixel-wise skin detection accuracy. Experimental results show that by using Random Forest classifier, the proposed SKN color space obtained an average F-score and True Positive Rate of 0.953 and False Positive Rate of 0.0482 which outperformed the existing color spaces in terms of pixel wise skin detection accuracy. The results also indicate that among the classifiers used in this study, Random Forest is the most suitable classifier for pixel wise skin detection applications. PMID:26267377

  7. A hybrid color space for skin detection using genetic algorithm heuristic search and principal component analysis technique.

    PubMed

    Maktabdar Oghaz, Mahdi; Maarof, Mohd Aizaini; Zainal, Anazida; Rohani, Mohd Foad; Yaghoubyan, S Hadi

    2015-01-01

    Color is one of the most prominent features of an image and used in many skin and face detection applications. Color space transformation is widely used by researchers to improve face and skin detection performance. Despite the substantial research efforts in this area, choosing a proper color space in terms of skin and face classification performance which can address issues like illumination variations, various camera characteristics and diversity in skin color tones has remained an open issue. This research proposes a new three-dimensional hybrid color space termed SKN by employing the Genetic Algorithm heuristic and Principal Component Analysis to find the optimal representation of human skin color in over seventeen existing color spaces. Genetic Algorithm heuristic is used to find the optimal color component combination setup in terms of skin detection accuracy while the Principal Component Analysis projects the optimal Genetic Algorithm solution to a less complex dimension. Pixel wise skin detection was used to evaluate the performance of the proposed color space. We have employed four classifiers including Random Forest, Naïve Bayes, Support Vector Machine and Multilayer Perceptron in order to generate the human skin color predictive model. The proposed color space was compared to some existing color spaces and shows superior results in terms of pixel-wise skin detection accuracy. Experimental results show that by using Random Forest classifier, the proposed SKN color space obtained an average F-score and True Positive Rate of 0.953 and False Positive Rate of 0.0482 which outperformed the existing color spaces in terms of pixel wise skin detection accuracy. The results also indicate that among the classifiers used in this study, Random Forest is the most suitable classifier for pixel wise skin detection applications.

  8. A Hybrid Color Space for Skin Detection Using Genetic Algorithm Heuristic Search and Principal Component Analysis Technique

    PubMed Central

    2015-01-01

    Color is one of the most prominent features of an image and used in many skin and face detection applications. Color space transformation is widely used by researchers to improve face and skin detection performance. Despite the substantial research efforts in this area, choosing a proper color space in terms of skin and face classification performance which can address issues like illumination variations, various camera characteristics and diversity in skin color tones has remained an open issue. This research proposes a new three-dimensional hybrid color space termed SKN by employing the Genetic Algorithm heuristic and Principal Component Analysis to find the optimal representation of human skin color in over seventeen existing color spaces. Genetic Algorithm heuristic is used to find the optimal color component combination setup in terms of skin detection accuracy while the Principal Component Analysis projects the optimal Genetic Algorithm solution to a less complex dimension. Pixel wise skin detection was used to evaluate the performance of the proposed color space. We have employed four classifiers including Random Forest, Naïve Bayes, Support Vector Machine and Multilayer Perceptron in order to generate the human skin color predictive model. The proposed color space was compared to some existing color spaces and shows superior results in terms of pixel-wise skin detection accuracy. Experimental results show that by using Random Forest classifier, the proposed SKN color space obtained an average F-score and True Positive Rate of 0.953 and False Positive Rate of 0.0482 which outperformed the existing color spaces in terms of pixel wise skin detection accuracy. The results also indicate that among the classifiers used in this study, Random Forest is the most suitable classifier for pixel wise skin detection applications. PMID:26267377

  9. The Skeletons' Halloween

    ERIC Educational Resources Information Center

    Bourque, Simone

    2010-01-01

    Mexican printer Jose Guadalupe Posada's (1851-1913) numerous prints of "calaveras" gave vast popularity to skeleton figures through his satirical and politically critical renditions of skeletons engaged in daily activities. They are oftentimes represented in festive and playful posturing. Calaveras have now become the most original trait of…

  10. Extraction and applications of skeletons in finite element mesh generation.

    SciTech Connect

    Quadros, William Roshan

    2010-05-01

    This paper focuses on the extraction of skeletons of CAD models and its applications in finite element (FE) mesh generation. The term 'skeleton of a CAD model' can be visualized as analogous to the 'skeleton of a human body'. The skeletal representations covered in this paper include medial axis transform (MAT), Voronoi diagram (VD), chordal axis transform (CAT), mid surface, digital skeletons, and disconnected skeletons. In the literature, the properties of a skeleton have been utilized in developing various algorithms for extracting skeletons. Three main approaches include: (1) the bisection method where the skeleton exists at equidistant from at least two points on boundary, (2) the grassfire propagation method in which the skeleton exists where the opposing fronts meet, and (3) the duality method where the skeleton is a dual of the object. In the last decade, the author has applied different skeletal representations in all-quad meshing, hex meshing, mid-surface meshing, mesh size function generation, defeaturing, and decomposition. A brief discussion on the related work from other researchers in the area of tri meshing, tet meshing, and anisotropic meshing is also included. This paper concludes by summarizing the strengths and weaknesses of the skeleton-based approaches in solving various geometry-centered problems in FE mesh generation. The skeletons have proved to be a great shape abstraction tool in analyzing the geometric complexity of CAD models as they are symmetric, simpler (reduced dimension), and provide local thickness information. However, skeletons generally require some cleanup, and stability and sensitivity of the skeletons should be controlled during extraction. Also, selecting a suitable application-specific skeleton and a computationally efficient method of extraction is critical.

  11. Segmentation and Reconstruction of Cultured Neuron Skeleton

    NASA Astrophysics Data System (ADS)

    Yu, Donggang; Pham, Tuan D.; Yan, Hong; Lai, Wei; Crane, Denis I.

    2007-11-01

    One approach to investigating neural death is through systematic studies of the changing morphology of cultured brain neurons in response to cellular challenges. Image segmentation and reconstruction methods developed to date to analyze such changes have been limited by the low contrast of cells. In this paper we present new algorithms that successfully circumvent these problems. The binary method is based on logical analysis of grey and distance difference of images. The spurious regions are detected and removed through use of a hierarchical window filter. The skeletons of binary cell images are extracted. The extension direction and connection points of broken cell skeletons are automatically determined, and broke neural skeletons are reconstructed. The spurious strokes are deleted based on cell prior knowledge. The efficacy of the developed algorithms is demonstrated here through a test of cultured brain neurons from newborn mice.

  12. Skeleton Pruning Based on the Total Bisector Angle of the End Branches

    NASA Astrophysics Data System (ADS)

    Zhang, Le; Matsumoto, Kazuyuki; Suzuki, Motoyuki; Kita, Kenji

    Skeletonization is an important technique for shape representation, but the skeleton's high sensitivity to boundary noise hampers its application to automatic shape matching. In this paper, we propose a linear-time skeleton pruning algorithm based on the total bisector angle of the end branches. The main idea of the proposed algorithm is to iteratively delete the end branches having the smallest total bisector angle. Since the total bisector angle considers both the local and the global skeleton information, the proposed algorithm removes all redundant branches generated by boundary noise and obtains the ideal skeleton. The experimental results show that the proposed algorithm is highly adaptable, which means that under the same threshold conditions, the pruned skeletons obtained by our proposed algorithm are in accord with human visual perception for most shapes in the MPEG-7 and Tari 56 datasets. Consequently, the pruned skeletons can be applied to automatic shape matching.

  13. The dynamic skeleton.

    PubMed

    Gonciulea, Anda; de Beur, Suzanne Jan

    2015-06-01

    Adding to its well-known roles in locomotion and calcium balance, the skeleton has recently been appreciated as a true endocrine organ. Bone remodeling, a highly dynamic process, requires synchronized activities and crosstalk between bone cells. Discovery and characterization of the Wnt/β catenin pathway in bone formation, FGF23 regulation of phosphate homeostasis and osteocalcin in energy and glucose homeostasis have reframed our view of the skeleton from simply a target tissue of the endocrine system to an endocrine tissue itself. This comprehensive review provides an overview of these complex pathways, their application to human bone disorders and implications for developing diagnostic and therapeutic targets.

  14. Skeletonization of Gridded Potential-Field Images

    NASA Astrophysics Data System (ADS)

    Gao, L.; Morozov, I. B.

    2012-12-01

    A new approach to skeletonization was developed for gridded potential-field data. Generally, skeletonization is a pattern-recognition technique allowing automatic recognition of near-linear features in the images, measurement of their parameters, and analyzing them for similarities. Our approach decomposes the images into arbitrarily-oriented "wavelets" characterized by positive or negative amplitudes, orientation angles, spatial dimensions, polarities, and other attributes. Orientations of the wavelets are obtained by scanning the azimuths to detect the strike direction of each anomaly. The wavelets are connected according to the similarities of these attributes, which leads to a "skeleton" map of the potential-field data. In addition, 2-D filtering is conducted concurrently with the wavelet-identification process, which allows extracting parameters of background trends and reduces the adverse effects of low-frequency background (which is often strong in potential-field maps) on skeletonization.. By correlating the neighboring wavelets, linear anomalies are identified and characterized. The advantages of this algorithm are the generality and isotropy of feature detection, as well as being specifically designed for gridded data. With several options for background-trend extraction, the stability for identification of lineaments is improved and optimized. The algorithm is also integrated in a powerful processing system which allows combining it with numerous other tools, such as filtering, computation of analytical signal, empirical mode decomposition, and various types of plotting. The method is applied to potential-field data for the Western Canada Sedimentary Basin, in a study area which extends from southern Saskatchewan into southwestern Manitoba. The target is the structure of crystalline basement beneath Phanerozoic sediments. The examples illustrate that skeletonization aid in the interpretation of complex structures at different scale lengths. The results

  15. Investigating the Human Skeleton.

    ERIC Educational Resources Information Center

    Slesnick, Irwin L.

    1982-01-01

    Instructions are provided for assembly of a pull-out, two-sided picture puzzle of the skeleton of a seven-year-old girl. Suggestions for activities using the assembled puzzle and comments on bones and bone morphology are also provided. (Author/JN)

  16. Skeletonizing a DEM into a drainage network

    NASA Astrophysics Data System (ADS)

    Meisels, Amnon; Raizman, Sonia; Karnieli, Arnon

    1995-02-01

    A new method for extracting drainage systems from Digital Elevation Models (DEMs) is presented. The main algorithm of the proposed method performs a skeletonization process of the set of elevations in the DEM and produces a skeleton of flow paths. An enumeration algorithm performs the removal of loops from the initial flow path. A preprocess for filling depressions is described as is the necessary postprocessing for determining the drainage network through depressions. The new method does not suffer from any of the maladies of former methods described in the literature, such as flow cutoffs, loops of flow, and basin flooding. The new method is tested on several real-world DEMs and produced connected, complete, and loopless networks.

  17. ISTP CDF Skeleton Editor

    NASA Technical Reports Server (NTRS)

    Chimiak, Reine; Harris, Bernard; Williams, Phillip

    2013-01-01

    Basic Common Data Format (CDF) tools (e.g., cdfedit) provide no specific support for creating International Solar-Terrestrial Physics/Space Physics Data Facility (ISTP/SPDF) standard files. While it is possible for someone who is familiar with the ISTP/SPDF metadata guidelines to create compliant files using just the basic tools, the process is error-prone and unreasonable for someone without ISTP/SPDF expertise. The key problem is the lack of a tool with specific support for creating files that comply with the ISTP/SPDF guidelines. There are basic CDF tools such as cdfedit and skeletoncdf for creating CDF files, but these have no specific support for creating ISTP/ SPDF compliant files. The SPDF ISTP CDF skeleton editor is a cross-platform, Java-based GUI editor program that allows someone with only a basic understanding of the ISTP/SPDF guidelines to easily create compliant files. The editor is a simple graphical user interface (GUI) application for creating and editing ISTP/SPDF guideline-compliant skeleton CDF files. The SPDF ISTP CDF skeleton editor consists of the following components: A swing-based Java GUI program, JavaHelp-based manual/ tutorial, Image/Icon files, and HTML Web page for distribution. The editor is available as a traditional Java desktop application as well as a Java Network Launching Protocol (JNLP) application. Once started, it functions like a typical Java GUI file editor application for creating/editing application-unique files.

  18. Skeleton of weighted social network

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Zhu, J.

    2013-03-01

    In the literature of social networks, understanding topological structure is an important scientific issue. In this paper, we construct a network from mobile phone call records and use the cumulative number of calls as a measure of the weight of a social tie. We extract skeletons from the weighted social network on the basis of the weights of ties, and we study their properties. We find that strong ties can support the skeleton in the network by studying the percolation characters. We explore the centrality of w-skeletons based on the correlation between some centrality measures and the skeleton index w of a vertex, and we find that the average centrality of a w-skeleton increases as w increases. We also study the cumulative degree distribution of the successive w-skeletons and find that as w increases, the w-skeleton tends to become more self-similar. Furthermore, fractal characteristics appear in higher w-skeletons. We also explore the global information diffusion efficiency of w-skeletons using simulations, from which we can see that the ties in the high w-skeletons play important roles in information diffusion. Identifying such a simple structure of a w-skeleton is a step forward toward understanding and representing the topological structure of weighted social networks.

  19. Skeleton-based shape analysis of protein models.

    PubMed

    Li, Zhong; Qin, Shengwei; Yu, Zeyun; Jin, Yao

    2014-09-01

    In order to compare the similarity between two protein models, a shape analysis algorithm based on skeleton extraction is presented in this paper. It firstly extracts the skeleton of a given protein surface by an improved Multi-resolution Reeb Graph (MRG) method. A number of points on the model surface are then collected to compute the local diameter (LD) according to the skeleton. Finally the LD frequency is calculated to build up the line chart, which is employed to analyze the shape similarity between protein models. Experimental results show that the similarity comparison using the proposed shape descriptor is more accurate especially for protein models with large deformations.

  20. The skeleton in space

    NASA Technical Reports Server (NTRS)

    Goode, A. W.; Rambaut, P. C.

    1985-01-01

    Calcium loss experience by astronauts under weightless conditions is discussed. I-125 photon absorption measurements on astronauts on the Apollo 14, 15, and 16 flights showed bone density decreases of 6.6 percent in one astronaut and 7.3 percent in another. The estimated total body calcium loss on Apollo 17 was 0.2 percent. The test results indicate that calcium losses occur mainly from the weight-bearing parts of the skeleton. Measures to counteract the losses include 'penguin' suits, maintenance of nutrient intakes at high levels, and extensive exercise on ergometer and treadmill.

  1. [WHAT SKELETONS TELL US].

    PubMed

    Catalano, Paola

    2015-01-01

    The recent excavations carried out by the Superintendence for the Colosseum, the Roman National Museum and the Archaeological Area of Rome allowed to uncover a large number of burial grounds of Imperial Age. In this work we present the data for 11 cemeteries scattered throughout the Suburbiumn, dating between 1st and 3rd centuries AD. A whole sample of 6061 tombs has been investigated and 5280 skeletons were anthropologically analyzed. All the field data have been scored in appropriate standardized charts in order to make easy their storage and processing in a dedicated database. PMID:27348986

  2. Path similarity skeleton graph matching.

    PubMed

    Bai, Xiang; Latecki, Longin Jan

    2008-07-01

    This paper presents a novel framework to for shape recognition based on object silhouettes. The main idea is to match skeleton graphs by comparing the shortest paths between skeleton endpoints. In contrast to typical tree or graph matching methods, we completely ignore the topological graph structure. Our approach is motivated by the fact that visually similar skeleton graphs may have completely different topological structures. The proposed comparison of shortest paths between endpoints of skeleton graphs yields correct matching results in such cases. The skeletons are pruned by contour partitioning with Discrete Curve Evolution, which implies that the endpoints of skeleton branches correspond to visual parts of the objects. The experimental results demonstrate that our method is able to produce correct results in the presence of articulations, stretching, and occlusion.

  3. Connexins in the skeleton.

    PubMed

    Stains, Joseph P; Civitelli, Roberto

    2016-02-01

    Shaping of the skeleton (modeling) and its maintenance throughout life (remodeling) require coordinated activity among bone forming (osteoblasts) and resorbing cells (osteoclasts) and osteocytes (bone embedded cells). The gap junction protein connexin43 (Cx43) has emerged as a key modulator of skeletal growth and homeostasis. The skeletal developmental abnormalities present in oculodentodigital and craniometaphyseal dysplasias, both linked to Cx43 gene (GJA1) mutations, demonstrate that the skeleton is a major site of Cx43 action. Via direct action on osteolineage cells, including altering production of pro-osteoclastogenic factors, Cx43 contributes to peak bone mass acquisition, cortical modeling of long bones, and maintenance of bone quality. Cx43 also contributes in diverse ways to bone responsiveness to hormonal and mechanical signals. Skeletal biology research has revealed the complexity of Cx43 function; in addition to forming gap junctions and "hemichannels", Cx43 provides a scaffold for signaling molecules. Hence, Cx43 actively participates in generation and modulation of cellular signals driving skeletal development and homeostasis. Pharmacological interference with Cx43 may in the future help remedy deterioration of bone quality occurring with aging, disuse and hormonal imbalances.

  4. Curve-skeleton extraction using iterative least squares optimization.

    PubMed

    Wang, Yu-Shuen; Lee, Tong-Yee

    2008-01-01

    A curve skeleton is a compact representation of 3D objects and has numerous applications. It can be used to describe an object's geometry and topology. In this paper, we introduce a novel approach for computing curve skeletons for volumetric representations of the input models. Our algorithm consists of three major steps: 1) using iterative least squares optimization to shrink models and, at the same time, preserving their geometries and topologies, 2) extracting curve skeletons through the thinning algorithm, and 3) pruning unnecessary branches based on shrinking ratios. The proposed method is less sensitive to noise on the surface of models and can generate smoother skeletons. In addition, our shrinking algorithm requires little computation, since the optimization system can be factorized and stored in the pre-computational step. We demonstrate several extracted skeletons that help evaluate our algorithm. We also experimentally compare the proposed method with other well-known methods. Experimental results show advantages when using our method over other techniques. PMID:18467765

  5. Computing Principal Eigenvectors of Large Web Graphs: Algorithms and Accelerations Related to PageRank and HITS

    ERIC Educational Resources Information Center

    Nagasinghe, Iranga

    2010-01-01

    This thesis investigates and develops a few acceleration techniques for the search engine algorithms used in PageRank and HITS computations. PageRank and HITS methods are two highly successful applications of modern Linear Algebra in computer science and engineering. They constitute the essential technologies accounted for the immense growth and…

  6. [Soft tissues, hormones and the skeleton].

    PubMed

    Zofková, I

    2012-02-01

    Mechanical load activates bone modeling and increases bone strength. Thus physical activity is extremely important for overall bone health. Muscle volume and muscle contraction are closely related to bone mineral density in men and women, although these relationships are more significat in men. The muscle-bone unit has been defined as a functional system, in which both components are under control of the somatotropin-IGF-I system, androgens and D hormone. These endocrine systems play, via the muscle-bone unit, an important role in development of the skeleton and its stability in adulthood. That is why deficiency of any of these hormonal systems, or reduced physical activity (mainly in childhood) could seriously affect bone density and quality. Bone is also under control of adipose tissue, which modulates its metabolism via mechanical load and more importantly via adipocytokines (leptin, adiponectin and rezistin). Leptin increases bone formation by activation of osteoblasts. This direct effect of leptin is amplified by stimulation of the β-1 adrenergic system, which inhibits the negative osteotropic effects of neuropeptide Y. On the other hand, leptin also activates β-2 adrenergic receptors, which increase bone resorption. In humans, the overall osteo-anabolic effect of leptin tends to be dominant. Furthermore, leptin has a principal role in the start of puberty in girls and maturation, remodeling and development of the female skeleton. Adiponectin (and probably rezistin) has an unambiguous deteriorating effect on the skeleton. Further studies are needed to confirm the clinical importance of soft tissues relative to the integrity of the skeleton.

  7. A Fast and Sensitive New Satellite SO2 Retrieval Algorithm based on Principal Component Analysis: Application to the Ozone Monitoring Instrument

    NASA Technical Reports Server (NTRS)

    Li, Can; Joiner, Joanna; Krotkov, A.; Bhartia, Pawan K.

    2013-01-01

    We describe a new algorithm to retrieve SO2 from satellite-measured hyperspectral radiances. We employ the principal component analysis technique in regions with no significant SO2 to capture radiance variability caused by both physical processes (e.g., Rayleigh and Raman scattering and ozone absorption) and measurement artifacts. We use the resulting principal components and SO2 Jacobians calculated with a radiative transfer model to directly estimate SO2 vertical column density in one step. Application to the Ozone Monitoring Instrument (OMI) radiance spectra in 310.5-340 nm demonstrates that this approach can greatly reduce biases in the operational OMI product and decrease the noise by a factor of 2, providing greater sensitivity to anthropogenic emissions. The new algorithm is fast, eliminates the need for instrument-specific radiance correction schemes, and can be easily adapted to other sensors. These attributes make it a promising technique for producing longterm, consistent SO2 records for air quality and climate research.

  8. The Milky Way Skeleton

    NASA Astrophysics Data System (ADS)

    Zucker, Catherine; Battersby, Cara; Goodman, Alyssa A.

    2015-01-01

    Recently, Goodman et al. (2014) argued that a very long, very thin infrared dark cloud 'Nessie' lies directly in the Galactic mid-plane and runs along the Scutum-Centaurus arm in position-position-velocity space as traced by low density CO and high density NH3 gas. Nessie was presented as the first 'bone' of the Milky Way, an extraordinarily long, thin, high contrast filament that can be used to map our galaxy's 'skeleton.' We present the first evidence of additional 'bones' in the Milky Way Galaxy, arguing that Nessie is not a curiosity but one of many filaments that could potentially trace galactic structure. Our ten bone candidates are all long, filamentary, mid-infrared extinction features which lie parallel to, and no more than twenty parsecs from, the physical Galactic mid-plane. We use CO, N2H+, and NH3 radial velocity data to establish the location of the candidates in position-velocity space. Of the ten filaments, three candidates have a projected aspect ratio of >50:1 and run along, or extremely close to, the Scutum-Centaurus arm in position-velocity space. Evidence suggests that these three candidates are Nessie-like features which mark the location of the spiral arms in both physical space and position-velocity space. Other candidates could be spurs, feathers, or interarm clouds associated with the Milky Way's galactic structure. As molecular spectral-line and extinction maps cover more of the sky at increasing resolution and sensitivity, we hope to find more bones in future studies, to ultimately create a global-fit to the Galaxy's spiral arms by piecing together individual skeletal features. This work is supported in part by the NSF REU and DOD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution.

  9. Delaunay algorithm and principal component analysis for 3D visualization of mitochondrial DNA nucleoids by Biplane FPALM/dSTORM.

    PubMed

    Alán, Lukáš; Špaček, Tomáš; Ježek, Petr

    2016-07-01

    Data segmentation and object rendering is required for localization super-resolution microscopy, fluorescent photoactivation localization microscopy (FPALM), and direct stochastic optical reconstruction microscopy (dSTORM). We developed and validated methods for segmenting objects based on Delaunay triangulation in 3D space, followed by facet culling. We applied them to visualize mitochondrial nucleoids, which confine DNA in complexes with mitochondrial (mt) transcription factor A (TFAM) and gene expression machinery proteins, such as mt single-stranded-DNA-binding protein (mtSSB). Eos2-conjugated TFAM visualized nucleoids in HepG2 cells, which was compared with dSTORM 3D-immunocytochemistry of TFAM, mtSSB, or DNA. The localized fluorophores of FPALM/dSTORM data were segmented using Delaunay triangulation into polyhedron models and by principal component analysis (PCA) into general PCA ellipsoids. The PCA ellipsoids were normalized to the smoothed volume of polyhedrons or by the net unsmoothed Delaunay volume and remodeled into rotational ellipsoids to obtain models, termed DVRE. The most frequent size of ellipsoid nucleoid model imaged via TFAM was 35 × 45 × 95 nm; or 35 × 45 × 75 nm for mtDNA cores; and 25 × 45 × 100 nm for nucleoids imaged via mtSSB. Nucleoids encompassed different point density and wide size ranges, speculatively due to different activity stemming from different TFAM/mtDNA stoichiometry/density. Considering twofold lower axial vs. lateral resolution, only bulky DVRE models with an aspect ratio >3 and tilted toward the xy-plane were considered as two proximal nucleoids, suspicious occurring after division following mtDNA replication. The existence of proximal nucleoids in mtDNA-dSTORM 3D images of mtDNA "doubling"-supported possible direct observations of mt nucleoid division after mtDNA replication.

  10. A Skeleton-Based 3D Shape Reconstruction of Free-Form Objects with Stereo Vision

    NASA Astrophysics Data System (ADS)

    Saini, Deepika; Kumar, Sanjeev

    2015-12-01

    In this paper, an efficient approach is proposed for recovering the 3D shape of a free-form object from its arbitrary pair of stereo images. In particular, the reconstruction problem is treated as the reconstruction of the skeleton and the external boundary of the object. The reconstructed skeleton is termed as the line-like representation or curve-skeleton of the 3D object. The proposed solution for object reconstruction is based on this evolved curve-skeleton. It is used as a seed for recovering shape of the 3D object, and the extracted boundary is used for terminating the growing process of the object. NURBS-skeleton is used to extract the skeleton of both views. Affine invariant property of the convex hulls is used to establish the correspondence between the skeletons and boundaries in the stereo images. In the growing process, a distance field is defined for each skeleton point as the smallest distance from that point to the boundary of the object. A sphere centered at a skeleton point of radius equal to the minimum distance to the boundary is tangential to the boundary. Filling in the spheres centered at each skeleton point reconstructs the object. Several results are presented in order to check the applicability and validity of the proposed algorithm.

  11. Skeleton deformation of red blood cells during tank treading motions

    NASA Astrophysics Data System (ADS)

    Zhu, Qiang; Peng, Zhangli

    2012-11-01

    By coupling a fluid-structure interaction algorithm with a three-level multiscale structural model, we simulate the tank treading responses of erythrocytes (red blood cells, or RBC) in shear flows. The fluid motion is depicted within the Stokes-flow framework, and is mathematically formulated with the boundary integral equations. The structural model takes into account the flexible connectivity between the lipid bilayer and the protein skeleton as well as the viscoelastic responses. The concentration of this study is on the transient process involving the development of the local area deformation of the protein skeleton. Under the assumption that the protein skeleton is stress-free in the natural biconcave configuration, our simulations indicate the following properties: (1) During tank treading motions it takes long time for significant area deformations to establish. For cells with diminished connectivity between the lipid bilayer and the protein skeleton (e.g. cells with mutations or defects), the relaxation time will be greatly reduced; (2) Deformations of the skeleton depend on the initial orientation of the cell with respect to the incoming flow; (3) The maximum area expansion occurs around the regions corresponding to the dimples in the original biconcave state; (4) Oscillations in cell geometry (breathing) and orientation (e.g. swinging) are observed. This work was supported by the National Heart, Lung, and Blood Institute under award number R01HL092793.

  12. Real-time skeleton tracking for embedded systems

    NASA Astrophysics Data System (ADS)

    Coleca, Foti; Klement, Sascha; Martinetz, Thomas; Barth, Erhardt

    2013-03-01

    Touch-free gesture technology is beginning to become more popular with consumers and may have a significant future impact on interfaces for digital photography. However, almost every commercial software framework for gesture and pose detection is aimed at either desktop PCs or high-powered GPUs, making mobile implementations for gesture recognition an attractive area for research and development. In this paper we present an algorithm for hand skeleton tracking and gesture recognition that runs on an ARM-based platform (Pandaboard ES, OMAP 4460 architecture). The algorithm uses self-organizing maps to fit a given topology (skeleton) into a 3D point cloud. This is a novel way of approaching the problem of pose recognition as it does not employ complex optimization techniques or data-based learning. After an initial background segmentation step, the algorithm is ran in parallel with heuristics, which detect and correct artifacts arising from insufficient or erroneous input data. We then optimize the algorithm for the ARM platform using fixed-point computation and the NEON SIMD architecture the OMAP4460 provides. We tested the algorithm with two different depth-sensing devices (Microsoft Kinect, PMD Camboard). For both input devices we were able to accurately track the skeleton at the native framerate of the cameras.

  13. THE SKELETON IN THE CLOSET

    PubMed Central

    Kaplan, Frederick S.

    2015-01-01

    The origins of fibrodysplasia ossificans progressiva (FOP) in human history are unknown but the condition has been well described since Freke’s account in 1740. Important contributions by physicians and scientists in the past two and a half centuries have converged on the remarkable skeleton of Harry Eastlack at The Mutter Museum of The College of Physicians in Philadelphia. PMID:23810943

  14. The skeleton in the closet.

    PubMed

    Kaplan, Frederick S

    2013-10-01

    The origins of fibrodysplasia ossificans progressiva (FOP) in human history are unknown but the condition has been well described since Freke's account in 1740. Important contributions by physicians and scientists in the past two and a half centuries have converged on the remarkable skeleton of Harry Eastlack at The Mutter Museum of The College of Physicians in Philadelphia.

  15. Making an Inexpensive Skeleton for the Classroom.

    ERIC Educational Resources Information Center

    Shaw, Edward L., Jr.; Pruitt, Nancy E.

    1990-01-01

    Presented is an activity in which a skeleton is built using papier mache' and various household items. The materials; procedures for building each part of the skeleton; and directions for painting, assembling, and varnishing are included. (KR)

  16. Inducting Principals.

    ERIC Educational Resources Information Center

    Andrews, Carl

    1989-01-01

    Principal induction is the process by which new school principals make the transition from theoretical to operational leadership. Many approaches to induction have been tried, ranging from simply handing over the building keys to comprehensive career development programs. To exemplify ongoing research and development in educational administration…

  17. Rock fracture skeleton tracing by image processing and quantitative analysis by geometry features

    NASA Astrophysics Data System (ADS)

    Liang, Yanjie

    2016-06-01

    In rock engineering, fracture measurement is important for many applications. This paper proposes a novel method for rock fracture skeleton tracing and analyzing. As for skeleton localizing, the curvilinear fractures are multiscale enhanced based on a Hessian matrix, after image binarization, and clutters are post-processed by image analysis; subsequently, the fracture skeleton is extracted via ridge detection combined with a distance transform and thinning algorithm, after which gap sewing and burrs removal repair the skeleton. In regard to skeleton analyzing, the roughness and distribution of a fracture network are respectively described by the fractal dimensions D s and D b; the intersection and fragmentation of a fracture network are respectively characterized by the average number of ends and junctions per fracture N average and the average length per fracture L average. Three rock fracture surfaces are analyzed for experiments and the results verify that both the fracture tracing accuracy and the analysis feasibility are satisfactory using the new method.

  18. Turnaround Principals

    ERIC Educational Resources Information Center

    McLester, Susan

    2011-01-01

    The Obama administration has grand hopes for turning around the nation's lowest-performing schools, in part by allocating $3.5 billion for School Improvement Grants. Unfortunately, there simply aren't enough qualified principals to replace those mandated to be fired under two of the four school improvement models that the federal government says…

  19. Principal Mentoring.

    ERIC Educational Resources Information Center

    Malone, Robert

    2001-01-01

    Increasing evidence shows that school leaders, throughout all stages of their careers, can benefit from a mentoring system in which a seasoned leader helps the protege combine theory and practice with experience. This research roundup reviews works that provide support for principal mentoring and share strategies for establishing mentoring…

  20. Hamilton-Jacobi skeleton on cortical surfaces.

    PubMed

    Shi, Y; Thompson, P M; Dinov, I; Toga, A W

    2008-05-01

    In this paper, we propose a new method to construct graphical representations of cortical folding patterns by computing skeletons on triangulated cortical surfaces. In our approach, a cortical surface is first partitioned into sulcal and gyral regions via the solution of a variational problem using graph cuts, which can guarantee global optimality. After that, we extend the method of Hamilton-Jacobi skeleton [1] to subsets of triangulated surfaces, together with a geometrically intuitive pruning process that can trade off between skeleton complexity and the completeness of representing folding patterns. Compared with previous work that uses skeletons of 3-D volumes to represent sulcal patterns, the skeletons on cortical surfaces can be easily decomposed into branches and provide a simpler way to construct graphical representations of cortical morphometry. In our experiments, we demonstrate our method on two different cortical surface models, its ability of capturing major sulcal patterns and its application to compute skeletons of gyral regions. PMID:18450539

  1. Network quotients: Structural skeletons of complex systems

    NASA Astrophysics Data System (ADS)

    Xiao, Yanghua; MacArthur, Ben D.; Wang, Hui; Xiong, Momiao; Wang, Wei

    2008-10-01

    A defining feature of many large empirical networks is their intrinsic complexity. However, many networks also contain a large degree of structural repetition. An immediate question then arises: can we characterize essential network complexity while excluding structural redundancy? In this article we utilize inherent network symmetry to collapse all redundant information from a network, resulting in a coarse graining which we show to carry the essential structural information of the “parent” network. In the context of algebraic combinatorics, this coarse-graining is known as the “quotient.” We systematically explore the theoretical properties of network quotients and summarize key statistics of a variety of “real-world” quotients with respect to those of their parent networks. In particular, we find that quotients can be substantially smaller than their parent networks yet typically preserve various key functional properties such as complexity (heterogeneity and hub vertices) and communication (diameter and mean geodesic distance), suggesting that quotients constitute the essential structural skeletons of their parent networks. We summarize with a discussion of potential uses of quotients in analysis of biological regulatory networks and ways in which using quotients can reduce the computational complexity of network algorithms.

  2. Bayesian estimation of the shape skeleton.

    PubMed

    Feldman, Jacob; Singh, Manish

    2006-11-21

    Skeletal representations of shape have attracted enormous interest ever since their introduction by Blum [Blum H (1973) J Theor Biol 38:205-287], because of their potential to provide a compact, but meaningful, shape representation, suitable for both neural modeling and computational applications. But effective computation of the shape skeleton remains a notorious unsolved problem; existing approaches are extremely sensitive to noise and give counterintuitive results with simple shapes. In conventional approaches, the skeleton is defined by a geometric construction and computed by a deterministic procedure. We introduce a Bayesian probabilistic approach, in which a shape is assumed to have "grown" from a skeleton by a stochastic generative process. Bayesian estimation is used to identify the skeleton most likely to have produced the shape, i.e., that best "explains" it, called the maximum a posteriori skeleton. Even with natural shapes with substantial contour noise, this approach provides a robust skeletal representation whose branches correspond to the natural parts of the shape.

  3. Skeleton-migration: Applications in deep crustal reflection seismic profiling

    NASA Astrophysics Data System (ADS)

    Eaton, D. W.; Vasudevan, K.

    2009-12-01

    The reflection geometry of the sub-surface is three-dimensional in character. A 3-D seismic data acquisition and processing would be the ideal modus operandi for true seismic interpretation. However, almost all deep-crustal reflection profiles recorded on land follow quasi-linear geometry, for economic reasons. Although conventional processing of the lines accommodates crooked-line geometry, the migration algorithms used to produce seismic images for interpretation are generally 2-D in nature. Consequently, the effects of 3-D geometry are not usually well-accounted for. For example, the out-of-plane reflections lead to mislocation errors that increase with recording time. The events may be mislocated by 10’s of km and show spurious apparent dip after migration. In order to circumvent these problems and to gain insight into 3-D structures, we present an easy-to-implement “Skeleton-migration” algorithm. The skeleton-migration method follows a two-step procedure. In the first step, we introduce a fast skeletonization of the final pre-processed stack to generate a digital catalogue containing a variety of event attributes including two-way travel times and location information in UTM co-ordinates. In the second step, we apply ray-based migration to the catalogue of events or two-way travel times of the 2-D stack using an appropriate velocity model for the crust and upper mantle. Since often we do not know a priori the strike direction of the reflectors, we have implemented a fast visualization-based optimization procedure to determine the strike. In subsequent steps, we use visualization methods to view and interpret the skeleton-migration results. We illustrate the usefulness of the method with examples from both the synthetic and deep crustal seismic reflection data. For the synthetic examples, we consider physical models corresponding to a point-scatterer, a synform, a fault and a subducting slab. In all these instances, we use an elastic Kirchhoff algorithm

  4. Building Up the Milky Way's Skeleton

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-09-01

    A team of scientistshas now uncovered half of theentire skeleton of the Milky Way, using an automated method to identify large filaments of gas and dust hiding between stars in the galactic plane.Galactic distribution of 54 newly discovered filaments, plotted along with colored lines indicating six relevant spiral arms in our galaxy. The upper two plots show the consistency of the filaments motion with the spiral arms, while the lower shows their location within the galactic plane. [Wang et al. 2016]The Search for Nessie and FriendsThe Milky Ways interstellar medium is structured hierarchically into filaments. These structures are difficult to observe since they largely lie in the galactic plane, but if we can discover the distribution and properties of these filaments, we can better understand how our galaxy formed, and how the filaments affect star formation in our galaxy today.Some of the largest of the Milky Ways filaments are hundreds of light-years long like the infrared dark cloud nicknamed Nessie, declared in 2013 to be one of the bones of the Milky Way because of its position along the center of the Scutum-Centaurus spiral arm.Follow-up studies since the discovery of Nessie (like this one, or this) have found a number of additional large-scale filaments, but these studies all use different search methods and selection criteria, and the searches all start with visual inspection by humans to identify candidates.What if we could instead automate the detection process and build a homogeneous sample of the large filaments making up the skeleton of the Milky Way?Automated DetectionThis is exactly what a team of astronomers led by Ke Wang (European Southern Observatory) has done. The group used a customization of an algorithm called a minimum spanning tree the technique used to optimize the cost of internet networks, road networks, and electrical grids in our communities to perform an automated search of data from the Bolocam Galactic Plane Survey. The search was

  5. Collagenous skeleton of the rat mystacial pad.

    PubMed

    Haidarliu, Sebastian; Simony, Erez; Golomb, David; Ahissar, Ehud

    2011-05-01

    Anatomical and functional integrity of the rat mystacial pad (MP) is dependent on the intrinsic organization of its extracellular matrix. By using collagen autofluorescence, in the rat MP, we revealed a collagenous skeleton that interconnects whisker follicles, corium, and deep collagen layers. We suggest that this skeleton supports MP tissues, mediates force transmission from muscles to whiskers, facilitates whisker retraction after protraction, and limits MP extensibility.

  6. Kernel Near Principal Component Analysis

    SciTech Connect

    MARTIN, SHAWN B.

    2002-07-01

    We propose a novel algorithm based on Principal Component Analysis (PCA). First, we present an interesting approximation of PCA using Gram-Schmidt orthonormalization. Next, we combine our approximation with the kernel functions from Support Vector Machines (SVMs) to provide a nonlinear generalization of PCA. After benchmarking our algorithm in the linear case, we explore its use in both the linear and nonlinear cases. We include applications to face data analysis, handwritten digit recognition, and fluid flow.

  7. Fast Steerable Principal Component Analysis

    PubMed Central

    Zhao, Zhizhen; Shkolnisky, Yoel; Singer, Amit

    2016-01-01

    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(nL3 + L4), while existing algorithms take O(nL4). 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. PMID:27570801

  8. Principal component analysis- adaptive neuro-fuzzy inference system modeling and genetic algorithm optimization of adsorption of methylene blue by activated carbon derived from Pistacia khinjuk.

    PubMed

    Ghaedi, M; Ghaedi, A M; Abdi, F; Roosta, M; Vafaei, A; Asghari, A

    2013-10-01

    In the present study, activated carbon (AC) simply derived from Pistacia khinjuk and characterized using different techniques such as SEM and BET analysis. This new adsorbent was used for methylene blue (MB) adsorption. Fitting the experimental equilibrium data to various isotherm models shows the suitability and applicability of the Langmuir model. The adsorption mechanism and rate of processes was investigated by analyzing time dependency data to conventional kinetic models and it was found that adsorption follow the pseudo-second-order kinetic model. Principle component analysis (PCA) has been used for preprocessing of input data and genetic algorithm optimization have been used for prediction of adsorption of methylene blue using activated carbon derived from P. khinjuk. In our laboratory various activated carbon as sole adsorbent or loaded with various nanoparticles was used for removal of many pollutants (Ghaedi et al., 2012). These results indicate that the small amount of proposed adsorbent (1.0g) is applicable for successful removal of MB (RE>98%) in short time (45min) with high adsorption capacity (48-185mgg(-1)).

  9. Prediction of radiation pressure force exerted on moving particles by the two-level skeletonization.

    PubMed

    Pan, Xiao-Min; Gou, Ming-Jiang; Sheng, Xin-Qing

    2014-04-21

    A fast full-wave method for computing radiation pressure force (RPF) exerted by shaped light beams on moving particles is presented. The problem of evaluating RPF exerted on a moving particle by a single excitation beam is converted into that of computing RPF's exerted on a static particle by multiple beams. The discretization of different beams leads to distinct right hand sides (RHS's) for the matrix system. To avoid solving each RHS by the brute-force manner, the algorithm conducts low-rank decomposition on the excitation matrix consisting of all RHS's to figure out the so-called skeleton light beams by interpolative decomposition (ID). The peak memory requirement of the skeletonization is a bottle-neck if the particle is large. A two-level skeletonization scheme is proposed to solve this problem. Some numerical experiments on arbitrarily shaped homogeneous particles are performed to illustrate the performance and capability of the developed method. PMID:24787885

  10. Classification of gasoline data obtained by gas chromatography using a piecewise alignment algorithm combined with feature selection and principal component analysis

    SciTech Connect

    Pierce, Karisa M.; Hope, Janiece L.; Johnson, Kevin J.; Wright, Bob W.; Synovec, Robert E.

    2005-11-25

    A fast and objective chemometric classification method is developed and applied to the analysis of gas chromatography (GC) data from five commercial gasoline samples. The gasoline samples serve as model mixtures, whereas the focus is on the development and demonstration of the classification method. The method is based on objective retention time alignment (referred to as piecewise alignment) coupled with analysis of variance (ANOVA) feature selection prior to classification by principal component analysis (PCA) using optimal parameters. The degree-of-class-separation is used as a metric to objectively optimize the alignment and feature selection parameters using a suitable training set thereby reducing user subjectivity, as well as to indicate the success of the PCA clustering and classification. The degree-of-class-separation is calculated using Euclidean distances between the PCA scores of a subset of the replicate runs from two of the five fuel types, i.e., the training set. The unaligned training set that was directly submitted to PCA had a low degree-of-class-separation (0.4), and the PCA scores plot for the raw training set combined with the raw test set failed to correctly cluster the five sample types. After submitting the training set to piecewise alignment, the degree-of-class-separation increased (1.2), but when the same alignment parameters were applied to the training set combined with the test set, the scores plot clustering still did not yield five distinct groups. Applying feature selection to the unaligned training set increased the degree-of-class-separation (4.8), but chemical variations were still obscured by retention time variation and when the same feature selection conditions were used for the training set combined with the test set, only one of the five fuels was clustered correctly. However, piecewise alignment coupled with feature selection yielded a reasonably optimal degree-of-class-separation for the training set (9.2), and when the

  11. Novel skeleton sesquiterpenoids isolated from guava leaves.

    PubMed

    Ouyang, Wen; Zhu, Xiao-ai; Wang, Wei; Chen, Xue-Xiang; Chen, Yun-Jiao; Cao, Yong

    2016-01-01

    A chemical investigation of the plant Psidium guajava L., collected in Guangdong province, afforded two novel skeleton sesquiterpenoids 1 and 2. Compound 2 also known as isocaryolan-9-one was a new natural product. The structure of the novel compound 1 was determined as guavacid A by various spectroscopic methods. A possible biosynthetic pathway for 1 and 2 was proposed. PMID:26308496

  12. Advances in evaluating the fetal skeleton

    PubMed Central

    Noel, Ann-Edwidge; Brown, Richard N

    2014-01-01

    In this review, we discuss aspects of the prenatal diagnosis of fetal skeletal malformations, concentrating on the advantages offered by different imaging techniques and the approaches that are of value in evaluating a suspected skeletal dysplasia. We also briefly address the findings in some of the commoner malformations of the fetal skeleton that may be encountered. PMID:24868173

  13. A Stochastic Skeleton Model for the MJO

    NASA Astrophysics Data System (ADS)

    thual, S.; Majda, A.; Stechmann, S.

    2013-12-01

    The Madden-Julian oscillation (MJO) is the dominant mode of variability in the tropical atmosphere on intraseasonal timescales and planetary spatial scales. In recent work by two of the authors, a minimal dynamical model has been proposed that recovers robustly the most fundamental MJO features of (I) a slow eastward speed of roughly 5 ms-1, (II) a peculiar dispersion relation with dω/dk≈ 0, and (III) a horizontal quadrupole vortex structure. This model, the skeleton model, depicts the MJO as a neutrally-stable atmospheric wave that involves a simple multiscale interaction between planetary dry dynamics, planetary lower-tropospheric moisture, and the planetary envelope of synoptic-scale activity. Here, we show that the skeleton model can further account for (IV) the intermittent generation of MJO events and (V) the organization of MJO events into wave trains with growth and demise, as seen in nature. We achieve this goal by developing a simple stochastic parametrization for the unresolved details of synoptic-scale activity, that is coupled to otherwise deterministic processes in the skeleton model. In particular, the intermittent initiation, propagation and shut down of MJO wave trains in the skeleton model occur through these stochastic effects. This includes examples with a background warm-pool where some initial MJO-like disturbances propagate through the western region but stall at the peak of background convection/heating corresponding to the maritime continent in nature.

  14. Isotropic microscale mechanical properties of coral skeletons

    PubMed Central

    Pasquini, Luca; Molinari, Alan; Fantazzini, Paola; Dauphen, Yannicke; Cuif, Jean-Pierre; Levy, Oren; Dubinsky, Zvy; Caroselli, Erik; Prada, Fiorella; Goffredo, Stefano; Di Giosia, Matteo; Reggi, Michela; Falini, Giuseppe

    2015-01-01

    Scleractinian corals are a major source of biogenic calcium carbonate, yet the relationship between their skeletal microstructure and mechanical properties has been scarcely studied. In this work, the skeletons of two coral species: solitary Balanophyllia europaea and colonial Stylophora pistillata, were investigated by nanoindentation. The hardness HIT and Young's modulus EIT were determined from the analysis of several load–depth data on two perpendicular sections of the skeletons: longitudinal (parallel to the main growth axis) and transverse. Within the experimental and statistical uncertainty, the average values of the mechanical parameters are independent on the section's orientation. The hydration state of the skeletons did not affect the mechanical properties. The measured values, EIT in the 76–77 GPa range, and HIT in the 4.9–5.1 GPa range, are close to the ones expected for polycrystalline pure aragonite. Notably, a small difference in HIT is observed between the species. Different from corals, single-crystal aragonite and the nacreous layer of the seashell Atrina rigida exhibit clearly orientation-dependent mechanical properties. The homogeneous and isotropic mechanical behaviour of the coral skeletons at the microscale is correlated with the microstructure, observed by electron microscopy and atomic force microscopy, and with the X-ray diffraction patterns of the longitudinal and transverse sections. PMID:25977958

  15. Depletion of membrane skeleton in red blood cell vesicles.

    PubMed Central

    Iglic, A; Svetina, S; Zeks, B

    1995-01-01

    A possible physical interpretation of the partial detachment of the membrane skeleton in the budding region of the cell membrane and consequent depletion of the membrane skeleton in red blood cell vesicles is given. The red blood cell membrane is considered to consist of the bilayer part and the membrane skeleton. The skeleton is, under normal conditions, bound to the bilayer over its whole area. It is shown that, when in such conditions it is in the expanded state, some cell shape changes can induce its partial detachment. The partial detachment of the skeleton from the bilayer is energetically favorable if the consequent decrease of the skeleton expansion energy is larger than the corresponding increase of the bilayer-skeleton binding energy. The effect of shape on the skeleton detachment is analyzed theoretically for a series of the pear class shapes, having decreasing neck diameter and ending with a parent-daughter pair of spheres. The partial detachment of the skeleton is promoted by narrowing of the cell neck, by increasing the lateral tension in the skeleton and its area expansivity modulus, and by diminishing the attraction forces between the skeleton and the bilayer. If the radius of the daughter vesicle is sufficiently small relative to the radius of the parent cell, the daughter vesicle can exist either completely underlaid with the skeleton or completely depleted of the skeleton. PMID:7669905

  16. Complete Primate Skeleton from the Middle Eocene of Messel in Germany: Morphology and Paleobiology

    PubMed Central

    Franzen, Jens L.; Gingerich, Philip D.; Habersetzer, Jörg; Hurum, Jørn H.; von Koenigswald, Wighart; Smith, B. Holly

    2009-01-01

    Background The best European locality for complete Eocene mammal skeletons is Grube Messel, near Darmstadt, Germany. Although the site was surrounded by a para-tropical rain forest in the Eocene, primates are remarkably rare there, and only eight fragmentary specimens were known until now. Messel has now yielded a full primate skeleton. The specimen has an unusual history: it was privately collected and sold in two parts, with only the lesser part previously known. The second part, which has just come to light, shows the skeleton to be the most complete primate known in the fossil record. Methodology/Principal Findings We describe the morphology and investigate the paleobiology of the skeleton. The specimen is described as Darwinius masillae n.gen. n.sp. belonging to the Cercamoniinae. Because the skeleton is lightly crushed and bones cannot be handled individually, imaging studies are of particular importance. Skull radiography shows a host of teeth developing within the juvenile face. Investigation of growth and proportion suggest that the individual was a weaned and independent-feeding female that died in her first year of life, and might have attained a body weight of 650–900 g had she lived to adulthood. She was an agile, nail-bearing, generalized arboreal quadruped living above the floor of the Messel rain forest. Conclusions/Significance Darwinius masillae represents the most complete fossil primate ever found, including both skeleton, soft body outline and contents of the digestive tract. Study of all these features allows a fairly complete reconstruction of life history, locomotion, and diet. Any future study of Eocene-Oligocene primates should benefit from information preserved in the Darwinius holotype. Of particular importance to phylogenetic studies, the absence of a toilet claw and a toothcomb demonstrates that Darwinius masillae is not simply a fossil lemur, but part of a larger group of primates, Adapoidea, representative of the early haplorhine

  17. School Without a Principal

    ERIC Educational Resources Information Center

    Hoban, Gary J.

    1976-01-01

    Discusses the type of person who becomes principal, the authority-responsibility of the principal, and the nonteaching resocialization of the principal and then offers a six-step model for eliminating the principalship. (Author/IRT)

  18. Helping Principals Cope.

    ERIC Educational Resources Information Center

    Quinn, Terrence

    2003-01-01

    Former principal suggests several ways to make principal's job more manageable: Revise the principal's job description, improve professional preparation, provide ongoing professional development, provide more support, improve management practices, and strengthen staff hiring. (PKP)

  19. Calcaneal spurs among San and Khoi skeletons.

    PubMed

    Caroline, Cermak; Kirchengast, Sylvia

    2015-01-01

    Only few studies considered the prevalence of calcaneal enthesophytes commonly called heel spurs among historic skeleton samples. In the present study the frequency of plantar calcaneal spurs among 54 19(th) century Khoisan skeletons was analyzed. Five individuals (9.6 %) had a plantar calcaneal spur at the right side or left side. Calcaneal spurs were more likely to occur in older individuals. More than 20 % of the individuals aged between 40 and 60 years (mature) showed plantar spurs, while 6.2 % of the individuals aged between 20 and 40 years had plantar spurs; however this difference was not significant. No sex differences were present in the prevalence of calcaneal spurs. Male and female individuals did not differ in the metric dimensions of the calcanceal spurs significantly.

  20. A Stochastic Skeleton Model for the MJO

    NASA Astrophysics Data System (ADS)

    Stechmann, S. N.; Thual, S.; Majda, A.

    2014-12-01

    The Madden-Julian oscillation (MJO) is the dominant mode of variability in the tropical atmosphere on intraseasonal time scales and planetary spatial scales. Despite the primary importance of the MJO and the decades of research progress since its original discovery, a generally accepted theory for its essential mechanisms has remained elusive. In recent work by two of the authors, a minimal dynamical model has been proposed that recovers robustly the most fundamental MJO features of (i) a slow eastward speed of roughly 5 m/s, (ii) a peculiar dispersion relation with dω/dk≈0, and (iii) a horizontal quadrupole vortex structure. This model, the skeleton model, depicts the MJO as a neutrally stable atmospheric wave that involves a simple multiscale interaction between planetary dry dynamics, planetary lower-tropospheric moisture, and the planetary envelope of synoptic-scale activity. In this article, it is shown that the skeleton model can further account for (iv) the intermittent generation of MJO events and (v) the organization of MJO events into wave trains with growth and demise, as seen in nature. The goal is achieved by developing a simple stochastic parameterization for the unresolved details of synoptic-scale activity, which is coupled to otherwise deterministic processes in the skeleton model. In particular, the intermittent initiation, propagation, and shut down of MJO wave trains in the skeleton model occur through these stochastic effects. This includes examples with a background warm pool where some initial MJO-like disturbances propagate through the western region but stall at the peak of background convection/heating corresponding to the Maritime Continent in nature. Also shown are examples with an idealized seasonal cycle, namely a background warm pool state of heating/moistening displacing meridionally during the year. This seasonally varying case considers both equatorial and off-equatorial components of the envelope of synoptic scale convective

  1. Principal Experiences of Succession

    ERIC Educational Resources Information Center

    Steele, Farla Gay

    2015-01-01

    This multiple case study explored the experiences of school principals and the usefulness of Peters' (2011) succession planning model. Ten purposefully selected principals from varying grade levels were interviewed; none reported a formal succession plan, and all had been assistant principals. The study concluded the assistant principal position…

  2. Principal Mentoring: An Update.

    ERIC Educational Resources Information Center

    Malone, Robert J.

    2002-01-01

    Never before has the need for effective mentoring programs for principals been more urgent. Record student enrollment, an anticipated retirement of about 40 percent of principals, and a shrinking pool of those who aspire to be principals have brought about a shortage of principals and an alarming lack of qualified applicants. This research roundup…

  3. Naked Stony Corals: Skeleton Loss in Scleractinia

    SciTech Connect

    Medina, Monica; Collins, Allen G.; Takaoka, Tori L.; Kuehl,Jennifer; Boore, Jeffrey L.

    2005-12-01

    Hexacorallia includes the Scleractinia, or stony corals, characterized by having an external calcareous skeleton made of aragonite, and the Corallimorpharia, or mushroom corals, that lack such a skeleton. Although each group has traditionally been considered monophyletic, some molecular phylogenetic analyses have challenged this, suggesting that skeletal features are evolutionarily plastic, and reviving notions that the scleractinian skeleton may be ephemeral and that the group itself may be polyphyletic. Nevertheless, the most comprehensive phylogenetic study of Hexacorallia supported scleractinian monophyly (REF), and so this remains controversial. In order to resolve this contentious issue, we sequenced the complete mitochondrial genome sequences of nine scleractinians and four corallimorpharians and performed phylogenetic analysis that also included three outgroups (an octocoral and two sea anemones). Our data provide the first strong evidence that Scleractinia is paraphyletic and that the Corallimorpharia is derived from within the group, from which we conclude that skeletal loss has occurred in the latter group secondarily. It is possible that a driving force in such skeletal loss could be the high levels of CO{sub 2} in the ocean during the mid-Cretaceous, which would have impacted aragonite solubility. We estimate from molecular divergence measures that the Corallimorpharia arose in the mid-Cretaceous, approximately 87 million years ago (Ma), supporting this view. These data also permit us to date the origin of Scleractinia to 265 Ma, narrowing the gap between the group's phylogenetic origin and its earliest fossil record.

  4. Principal Preparedness: Superintendent Perceptions of New Principals

    ERIC Educational Resources Information Center

    Cray, Martha; Weiler, Spencer C.

    2011-01-01

    National advocacy groups have undertaken significant efforts to define the performance capacities needed by principals to lead schools in this era of continuous improvement and accountability. There has been little articulation between the core skills essential to new principals and the leadership capacities of experienced peers. This study…

  5. Development and evaluation of a semi-automatic technique for determining the bilateral symmetry plane of the facial skeleton.

    PubMed

    Willing, Ryan T; Roumeliotis, Grayson; Jenkyn, Thomas R; Yazdani, Arjang

    2013-12-01

    During reconstructive surgery of the face, one side may be used as a template for the other, exploiting assumed bilateral facial symmetry. The best method to calculate this plane, however, is debated. A new semi-automatic technique for calculating the symmetry plane of the facial skeleton is presented here that uses surface models reconstructed from computed tomography image data in conjunction with principal component analysis and an iterative closest point alignment method. This new technique was found to provide more accurate symmetry planes than traditional methods when applied to a set of 7 human craniofacial skeleton specimens, and showed little vulnerability to missing model data, usually deviating less than 1.5° and 2 mm from the intact model symmetry plane when 30 mm radius voids were present. This new technique will be used for subsequent studies measuring symmetry of the facial skeleton for different patient populations.

  6. Stereoselective synthesis of (+)-loline alkaloid skeleton.

    PubMed

    Miller, Kelsey E; Wright, Anthony J; Olesen, Margaret K; Hovey, M Todd; Scheerer, Jonathan R

    2015-02-01

    The loline alkaloids present a compact polycyclic pyrrolizidine skeleton and contain a strained five-membered ethereal bridge, structural features that have proven challenging for synthetic chemists to incorporate since the discovery of this natural product family more than 100 years ago. These alkaloids are produced by mutualistic fungal symbionts (endophytes) living on certain species of pasture grasses and protect the host plant from insect herbivory. The asymmetric total synthesis of loline alkaloids is reported and extends our first-generation (racemic) synthesis of this alkaloid family. Key to the synthesis is a diastereoselective tethered aminohydroxylation of a homoallylic carbamate function and a Petasis Borono-Mannich addition.

  7. Switching skeletons: hydrostatic support in molting crabs

    NASA Technical Reports Server (NTRS)

    Taylor, Jennifer R A.; Kier, William M.; Walker, I. D. (Principal Investigator)

    2003-01-01

    Skeletal support systems are essential for support, movement, muscular antagonism, and locomotion. Crustaceans shed their rigid exoskeleton at each molt yet are still capable of forceful movement. We hypothesize that the soft water-inflated body of newly molted crabs may rely on a hydrostatic skeleton, similar to that of worms and polyps. We measured internal hydrostatic pressure and the force exerted during claw adduction and observed a strong correlation between force and hydrostatic pressure, consistent with hydrostatic skeletal support. This alternation between the two basic skeletal types may be widespread among arthropods.

  8. Fish-skeleton visualization of bending actuators

    NASA Astrophysics Data System (ADS)

    Nakshatharan, Sunjai; Punning, Andres; Assi, Siim; Johanson, Urmas; Aabloo, Alvo

    2016-04-01

    We present a novel experimental method for qualitative visualization and quantitative characterization of the time-dependent behavior of bending ionic electroactive polymer actuators. The thin fibers, attached to the actuator, represent the surface normal at the given points of the bending actuator. The structure, formed by the skeleton of many adjacent fibers, amplifies the visual overview about the whole actuator. The four coordinates formed by four tips of two fibers enable determining the axial as well as the bending strains of a bending actuator.

  9. Principal Mentoring. ERIC Digest.

    ERIC Educational Resources Information Center

    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 digest examines the nature of mentorships and discusses how they can prepare principals for the next stage of their careers. Although mentoring has existed…

  10. Principal Selection Guide.

    ERIC Educational Resources Information Center

    Office of Educational Research and Improvement (ED), Washington, DC.

    The choice of principals is too important to be left to chance. Dynamic, committed leaders not only help determine the quality of teachers that are recruited, but provide the key to effective schools where the battle for excellence will be won or lost. Section 1, "The Effective Principal," outlines the tasks that an effective principal performs.…

  11. Elementary School Principal Effectiveness.

    ERIC Educational Resources Information Center

    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 fared…

  12. The Provident Principal.

    ERIC Educational Resources Information Center

    McCall, John R.

    This monograph offers leadership approaches for school principals. Discussion applies the business leadership theory of Warren Bennis and Burt Nanus to the role of the principal. Each of the booklet's three parts concludes with discussion questions. Part 1, "Visions and Values for the Provident Principal," demonstrates the importance of…

  13. [Wooden models of human skeleton made in Edo era, Japan, with special reference to Hoshino wooden skeleton].

    PubMed

    Kataoka, Katsuko; Suzaki, Etsuko; Ajima, Noriaki

    2006-03-01

    The wooden model of the human skeleton, called wooden skeleton, is a distinguished original craft object in Edo era (1600-1867), Japan, when medical doctors were unable to keep the human skeleton for their study and teaching purpose. There are three kinds of wooden skeletons, i. e. Hoshino, Kagami and Okuda wooden skeletons made in 1792, 1810 and 1820, respectively. The former two are of adult male and the latter of female. They were made in surprising accuracy as compared with figures appeared in medical books available in Japan at that time, which suggests scientific readiness of the doctors and skills of the craftsmen. A complete set of the skeleton, except for the hyoid bone, has been preserved for Hoshino and Okuda wooden skeletons, while several bones have been missing in Kagami wooden skeleton. Each bone of Hoshino and Kagami wooden skeletons was made separately and connected by a tenon and a corresponding mortise at the articular surface. So it is hardly considered that all wooden bones were assembled into the whole body skeleton on use. Okuda wooden skeleton, on the other hand, was made for being shown in sitting position. The skull of Hoshino wooden skeleton is of special interest: the skull cap is not open, yet the internal structures of the skull, such as the sella turcica, foramina for nerves and vessels, and sulci for venous sinuses were made in considerable accuracy. Moreover, the proper connection of most foramina was proved between the inside and outside of the skull. The skull caps of Kagami and Okuda wooden skeletons are open as those used in the modern medical education.

  14. Skeletal metastasis: the effect on immature skeleton

    SciTech Connect

    Ogden, J.A.; Ogden, D.A.

    1982-12-01

    The unique opportunity to study the entire appendicular skeleton of a child who died from metastatic angiosarcoma allowed detailed assessment of radiographically evident involvement. Virtually every portion of the appendicular skeleton had evidence of metastatic disease. However, the extent of involvement was extremely variable, especially when contralateral regions were assessed. The most likely region of metastasis, the metaphysis, is normally a fenestrated cortex of woven bone in the young child, rather than a well demarcated cortex formed by osteon (lamellar) bone, as it is in the adult. The pattern of destruction is such that less extensive areas may be involved before becoming radiographically evident, and trabecular bone involvement may be evident even without cortical damage. The metaphyseal metastatic spread supports the concept of arterial hematogeneous dissemination, comparable to osteomyelitis in the child. Pathologic metaphyseal fractures involved both proximal humeri; the fracture also extended along a portion of the methaphyseal-physeal interface in one humerus. In one distal femur the physis readily separated from the metaphysis; this was a nondisplaced type 1 growth mechanism injury.

  15. Mineralization of the Sea Urchin Skeleton

    NASA Astrophysics Data System (ADS)

    Wilt, F.

    2001-12-01

    The sea urchin possess a calcareous skeleton composed of over 99% magnesian calcite,an enveloping extracellular matrix, and an occluded protein matrix. The most intensively studied skeletal element is the spicule of the embryo. At the 32 cell stage of development a cohort of 4 cells becomes irrevocably dedicated to spicule formation. At the early gastrula stage the descendants of these founder cells form the primary mesenchyme (PMC). The PMCs fuse to form a multinucleated syncytium connected by cytoplasmic cables, and the calcitic skeleton is formed within these cables. Our primary concern is with the cellular and molecular mechanisms that support the formation of the mineralized spicules. The import of calcium into the PMCs results in appearance of intracellular vesicles containing precipitated calcium, which is neither very stable nor birefringent, and could be amorphous. The precipitated calcium is vectorially secreted into an extracellular space. This space is almost completely enclosed by cytoplasmic strands, and the mineral is encased in an extracellular matrix. Proteins destined for the extracellular matrix, and for inclusion in the spicule, are present in the Golgi membranes and in small intracellular vesicles. These vesicles apparently deliver the matrix proteins to the growing spicule. Our current view is that the matrix molecules are much more than a passive armature, but are actively involved in precipitation, secretion, and organization of the mineral phase.

  16. Landform skeleton reconstruction from unorganized points

    NASA Astrophysics Data System (ADS)

    Luo, Mingliang; Tang, Guoan; Liu, Xuejun; Bian, Lu

    2007-11-01

    Landform skeleton are lines that indicate significant topographic features of the terrain. It is widely used in mapping and surveying, hydrology simulation, topography representation and engineering designing. In order to derive the landform skeleton, many kinds of data source have been used, including digitized contour lines, Grid-DEMs and TIN. As time goes by, more and more unorganized points have been acquired, created, maintained and disseminated in many fields. Those unorganized points are the most original and important information which is vital for mapping and surveying. How to extract the feature lines from unorganized points has been the hot-pot in computer design and reverse-engineering. Methods used to extract landform features in existence have shown dependence on data types and thresholds more or less. In the paper, the view sheds principle used to extract the feature points has been put forward and then those points have been organized into feature lines according to related rules. The result has shown that the view sheds principle can extract the features and give the levels of feature points.

  17. [Okuda wooden human skeleton made in Edo era, Japan].

    PubMed

    Baba, Hisao

    2006-03-01

    Probably in 1820 (late Edo era), a human skeleton for medical education was carved from cypress wood, based on a criminal's skeleton under the supervision of a medical doctor, Banri Okuda in Osaka City. The skeleton is called "Okuda wooden skeleton" and is now housed in the National Science Museum, Tokyo. The bones can be assembled into a skeleton by metal pivots or bamboo sticks. The thorax and pelvis were made of several pieces of wood and combined together, respectively. By and large, the wooden skeleton shows morphological characteristics usually seen in early middle-aged females of the Edo era. But the claviculae, distal ends of the femora, and the patellae are exceptionally larger than those of a female, implying that these bones of the original skeleton had already been lost or were deformed before the wooden skeleton was made. Actually the wooden skeleton might not have been used for medical education but rather for the promotion of European medicine, which was gradually developing in the Edo era.

  18. The Hoshino wooden skeleton, the first wooden model of a human skeleton, made during the Edo era in Japan.

    PubMed

    Kataoka, Katsuko; Suzaki, Etsuko; Ajima, Noriaki

    2007-03-01

    The wooden model of the human skeleton, called the wooden skeleton, is a distinguished original craft object from the Edo era, in Japan, when medical doctors were unable to keep a human skeleton for study and teaching purposes. There are three types of wooden skeletons: (i) Hoshino made in 1792; (ii) Kagami made by 1810; and (iii) Okuda made around 1820. The former two are of adult males and the latter is of a female. The wooden skeletons were made with surprising accuracy compared with figures that appeared in the medical books available in Japan at that time, which suggests a scientific readiness of the doctors and the skill of the craftsmen. In the cases of the Hoshino and Kagami wooden skeletons, it is hard to consider that all wooden bones were assembled to show the entire body. Conversely, the Okuda wooden skeletons were made for showing in the sitting position. The skull of the Hoshino wooden skeleton is of special interest: the skull cap was not cut, yet the internal structures of the skull, such as the sella turcica, foramina for nerves and vessels, and the sulci for venous sinuses, were made with considerable accuracy. The skull caps of the Kagami and Okuda wooden skeletons were cut, as those used in modern medical education.

  19. Harried Principals Aren't Helpful Principals

    ERIC Educational Resources Information Center

    Connolly, Mike

    2007-01-01

    A harried leader is not a helpful leader. Schools need calm, well-balanced, helpful leaders as much as they need visionary ones. In fact, in this era of frenetic change in schools, principals should devote at least as much time to helping teachers be more focused and less frantic as they do to formulating new visions for the school or embarking on…

  20. Redesigning Principal Internships: Practicing Principals' Perspectives

    ERIC Educational Resources Information Center

    Anast-May, Linda; Buckner, Barbara; Geer, Gregory

    2011-01-01

    Internship programs too often do not provide the types of experiences that effectively bridge the gap between theory and practice and prepare school leaders who are capable of leading and transforming schools. To help address this problem, the current study is directed at providing insight into practicing principals' views of the types of…

  1. Biology of bone and how it orchestrates the form and function of the skeleton

    NASA Technical Reports Server (NTRS)

    Sommerfeldt, D. W.; Rubin, C. T.

    2001-01-01

    The principal role of the skeleton is to provide structural support for the body. While the skeleton also serves as the body's mineral reservoir, the mineralized structure is the very basis of posture, opposes muscular contraction resulting in motion, withstands functional load bearing, and protects internal organs. Although the mass and morphology of the skeleton is defined, to some extent, by genetic determinants, it is the tissue's ability to remodel--the local resorption and formation of bone--which is responsible for achieving this intricate balance between competing responsibilities. The aim of this review is to address bone's form-function relationship, beginning with extensive research in the musculoskeletal disciplines, and focusing on several recent cellular and molecular discoveries which help understand the complex interdependence of bone cells, growth factors, physical stimuli, metabolic demands, and structural responsibilities. With a clinical and spine-oriented audience in mind, the principles of bone cell and molecular biology and physiology are presented, and an attempt has been made to incorporate epidemiologic data and therapeutic implications. Bone research remains interdisciplinary by nature, and a deeper understanding of bone biology will ultimately lead to advances in the treatment of diseases and injuries to bone itself.

  2. The origin of the vertebrate skeleton

    NASA Astrophysics Data System (ADS)

    Pivar, Stuart

    2011-01-01

    The anatomy of the human and other vertebrates has been well described since the days of Leonardo da Vinci and Vesalius. The causative origin of the configuration of the bones and of their shapes and forms has been addressed over the ensuing centuries by such outstanding investigators as Goethe, Von Baer, Gegenbauer, Wilhelm His and D'Arcy Thompson, who sought to apply mechanical principles to morphogenesis. However, no coherent causative model of morphogenesis has ever been presented. This paper presents a causative model for the origin of the vertebrate skeleton, based on the premise that the body is a mosaic enlargement of self-organized patterns engrained in the membrane of the egg cell. Drawings illustrate the proposed hypothetical origin of membrane patterning and the changes in the hydrostatic equilibrium of the cytoplasm that cause topographical deformations resulting in the vertebrate body form.

  3. The skeleton as an endocrine organ.

    PubMed

    DiGirolamo, Douglas J; Clemens, Thomas L; Kousteni, Stavroula

    2012-11-01

    Surprising new discoveries in the field of skeletal biology show that bone cells produce endocrine hormones that regulate phosphate and glucose homeostasis. In this Review, we examine the features of these new endocrine pathways and discuss their physiological importance in the context of our current understanding of energy metabolism and mineral homeostasis. Consideration of evolutionary and comparative biology provides clues that a key driving force for the emergence of these hormonal pathways was the development of a large, energy-expensive musculoskeletal system. Specialized bone cells also evolved and produced endocrine hormones to integrate the skeleton in global mineral and nutrient homeostasis. The recognition of bone as a true endocrine organ represents a fertile area for further research and should improve the diagnosis and treatment of metabolic diseases such as osteoporosis and diabetes mellitus.

  4. DEVELOPMENTAL PALEOBIOLOGY OF THE VERTEBRATE SKELETON

    PubMed Central

    RÜCKLIN, MARTIN; DONOGHUE, PHILIP C. J.; CUNNINGHAM, JOHN A.; MARONE, FEDERICA; STAMPANONI, MARCO

    2015-01-01

    Studies of the development of organisms can reveal crucial information on homology of structures. Developmental data are not peculiar to living organisms, and they are routinely preserved in the mineralized tissues that comprise the vertebrate skeleton, allowing us to obtain direct insight into the developmental evolution of this most formative of vertebrate innovations. The pattern of developmental processes is recorded in fossils as successive stages inferred from the gross morphology of multiple specimens and, more reliably and routinely, through the ontogenetic stages of development seen in the skeletal histology of individuals. Traditional techniques are destructive and restricted to a 2-D plane with the third dimension inferred. Effective non-invasive methods of visualizing paleohistology to reconstruct developmental stages of the skeleton are necessary. In a brief survey of paleohistological techniques we discuss the pros and cons of these methods. The use of tomographic methods to reconstruct development of organs is exemplified by the study of the placoderm dentition. Testing evidence for the presence of teeth in placoderms, the first jawed vertebrates, we compare the methods that have been used. These include inferring the development from morphology, and using serial sectioning, microCT or synchrotron X-ray tomographic microscopy (SRXTM) to reconstruct growth stages and directions of growth. The ensuing developmental interpretations are biased by the methods and degree of inference. The most direct and reliable method is using SRXTM data to trace sclerochronology. The resulting developmental data can be used to resolve homology and test hypotheses on the origin of evolutionary novelties. PMID:26306050

  5. Anatomy of the red cell membrane skeleton: unanswered questions.

    PubMed

    Lux, Samuel E

    2016-01-14

    The red cell membrane skeleton is a pseudohexagonal meshwork of spectrin, actin, protein 4.1R, ankyrin, and actin-associated proteins that laminates the inner membrane surface and attaches to the overlying lipid bilayer via band 3-containing multiprotein complexes at the ankyrin- and actin-binding ends of spectrin. The membrane skeleton strengthens the lipid bilayer and endows the membrane with the durability and flexibility to survive in the circulation. In the 36 years since the first primitive model of the red cell skeleton was proposed, many additional proteins have been discovered, and their structures and interactions have been defined. However, almost nothing is known of the skeleton's physiology, and myriad questions about its structure remain, including questions concerning the structure of spectrin in situ, the way spectrin and other proteins bind to actin, how the membrane is assembled, the dynamics of the skeleton when the membrane is deformed or perturbed by parasites, the role lipids play, and variations in membrane structure in unique regions like lipid rafts. This knowledge is important because the red cell membrane skeleton is the model for spectrin-based membrane skeletons in all cells, and because defects in the red cell membrane skeleton underlie multiple hemolytic anemias.

  6. Skeleton Graph Matching vs. Maximum Weight Cliques aorta registration techniques.

    PubMed

    Czajkowska, Joanna; Feinen, C; Grzegorzek, M; Raspe, M; Wickenhöfer, R

    2015-12-01

    Vascular diseases are one of the most challenging health problems in developed countries. Past as well as ongoing research activities often focus on efficient, robust and fast aorta segmentation, and registration techniques. According to this needs our study targets an abdominal aorta registration method. The investigated algorithms make it possible to efficiently segment and register abdominal aorta in pre- and post-operative Computed Tomography (CT) data. In more detail, a registration technique using the Path Similarity Skeleton Graph Matching (PSSGM), as well as Maximum Weight Cliques (MWCs) are employed to realise the matching based on Computed Tomography data. The presented approaches make it possible to match characteristic voxels belonging to the aorta from different Computed Tomography (CT) series. It is particularly useful in the assessment of the abdominal aortic aneurysm treatment by visualising the correspondence between the pre- and post-operative CT data. The registration results have been tested on the database of 18 contrast-enhanced CT series, where the cross-registration analysis has been performed producing 153 matching examples. All the registration results achieved with our system have been verified by an expert. The carried out analysis has highlighted the advantage of the MWCs technique over the PSSGM method. The verification phase proves the efficiency of the MWCs approach and encourages to further develop this methods.

  7. Purification and proteomic analysis of liver membrane skeletons.

    PubMed

    He, Jintang; Liu, Yashu; Wang, Qingsong; Ji, Jianguo

    2012-01-01

    The detergent-resistant membrane skeletons play a critical role in cell shaping and signaling. The focus of the methods described in this chapter is first on the preparation of membrane skeletons from liver by multistep sucrose density gradient centrifugation, and then on the analysis of the protein components of membrane skeletons using proteomics techniques. Two proteomic analysis strategies are described. In the first strategy, membrane skeleton proteins are separated by two-dimensional gel electrophoresis and identified by matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry. In the other strategy, proteins are separated by SDS-PAGE and identified by liquid chromatography-electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The methods facilitate the understanding of the structure of membrane skeletons.

  8. Renewing the Principal Pipeline

    ERIC Educational Resources Information Center

    Turnbull, Brenda J.

    2015-01-01

    The work principals do has always mattered, but as the demands of the job increase, it matters even more. Perhaps once they could maintain safety and order and call it a day, but no longer. Successful principals today must also lead instruction and nurture a productive learning community for students, teachers, and staff. They set the tone for the…

  9. Competency Development for Principals.

    ERIC Educational Resources Information Center

    Snyder, Karolyn J.

    This paper describes two conceptual models for addressing long-range development needs of principals. The first, a job competency model for managing productive schools, presents a comprehensive view of the central job tasks of the principal for stretching the school's capacity to influence achievement norms. Changing the school's work norms…

  10. Priming Principal Pipelines

    ERIC Educational Resources Information Center

    Schachter, Ron

    2013-01-01

    Most principals today are hard pressed to find time for the multitasking they are expected to do, from overseeing the daily operation of their schools and interacting with parents to evaluating teachers and providing them with professional development to do their jobs at a high level. What these principals have frequently been lacking, say experts…

  11. Behaviours of Effective Principals.

    ERIC Educational Resources Information Center

    Moorhead, Roslyn; Nediger, William

    The purpose of this 2-year-long qualitative and quantitative field study was to investigate the behaviors of effective secondary school principals in their respective school districts, to find commonalities in the behavior of principals who were deemed by their peers to preside over effective schools, and to report the interim results. The…

  12. Qualities of Effective Principals

    ERIC Educational Resources Information Center

    Stronge, James H.; Richard, Holly B.; Catano, Nancy

    2008-01-01

    You know how important principals are in advancing student achievement and school success, but it's not been exactly clear which components of the principal's job are the highest priority... until now. Following on the results-based approach from the ASCD best-seller "Qualities of Effective Teachers", James Stronge and his coauthors…

  13. Essential Skills for Principals.

    ERIC Educational Resources Information Center

    Terry, Paul M.

    1999-01-01

    No matter what standards they follow, principals must be skilled team builders, instructional leaders, and visionary risk-takers. There are five emerging roles: historian, cheerleader, lightning rod, landscaper (environmental scanner), and anthropologist. To succeed, principals must be empowered by districts, become authentic leaders, and make…

  14. Of Principals and Projects.

    ERIC Educational Resources Information Center

    Wyant, Spencer H.; And Others

    Principals play an important role in the success of externally funded change projects in their schools. Interviews exploring the participation of principals in such projects in 14 Oregon elementary and secondary schools provided 11 case studies illustrating helpful and unhelpful behaviors. The projects were found to have life cycles of their own,…

  15. A Principal's Reaction

    ERIC Educational Resources Information Center

    Zaretsky, Lindy

    2004-01-01

    This article presents a principal's reaction to Catherine Marshall and Michael Ward's article on research on social justice and training for leadership. The author applauds Marshall and Ward's efforts to address what is undoubtedly among the most fundamentally important issues facing principals today. Marshall and Ward illuminate the importance of…

  16. Principal Preparation Programs

    ERIC Educational Resources Information Center

    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,…

  17. Principals as Instructional Leaders

    ERIC Educational Resources Information Center

    Finkel, Ed

    2012-01-01

    At some level, principals always have been instructional leaders--but never before has their role been more prominent. First, the accountability movement--No Child Left Behind (NCLB) in particular--thrust principals into the spotlight on academic achievement. Then budget cuts peeled away capacity at both the district and school levels, thinning…

  18. Good Principals, Good Schools.

    ERIC Educational Resources Information Center

    Adams, Jeanne P.

    1999-01-01

    A three-county survey of administrative credential students in California found that 26% of respondents serving in administrative positions are considering leaving their jobs; 62% of qualified candidates are staying in the classroom. Solutions to principal overload include hiring more assistant principals and grooming inhouse talent. (MLH)

  19. Real Principals Listen

    ERIC Educational Resources Information Center

    Glover, Eric

    2007-01-01

    Many teachers fear that their chances to influence decisions about their profession are eroding. Principals must change this perception so that teachers feel empowered as school leaders. Drawing on the work of communications consultant William Isaacs, Glover discusses how principals can engage in communication that encourages teacher leadership by…

  20. Principals' Perceptions of Politics

    ERIC Educational Resources Information Center

    Tooms, Autumn K.; Kretovics, Mark A.; Smialek, Charles A.

    2007-01-01

    This study is an effort to examine principals' perceptions of workplace politics and its influence on their productivity and efficacy. A survey was used to explore the perceptions of current school administrators with regard to workplace politics. The instrument was disseminated to principals serving public schools in one Midwestern state in the…

  1. A Principal's Journey

    ERIC Educational Resources Information Center

    Yergalonis, Edward

    2005-01-01

    In the interview process, every aspiring principal naively speaks of assuming the role of instructional leader. The candidate has read the right books, taken the right courses, and attended every possible workshop to prepare for the day when he or she would become captain of his or her own ship. However, it does not take long for principals to…

  2. The Principal Factor

    ERIC Educational Resources Information Center

    Westerberg, Tim

    2016-01-01

    If classrooms teachers play the lead role in establishing relationships that help students do their personal best, principals are leaders in creating good school environments for adults. Westerberg, former principal of award-winning Littleton High School in Colorado, shares six principles that help create positive schoolwide relationships. Drawing…

  3. Principals from Hell

    ERIC Educational Resources Information Center

    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…

  4. The Principal As Manager.

    ERIC Educational Resources Information Center

    Mallia, Margaret

    Findings of a study of beginning principals and their roles as managers are presented in this paper. Interviews were conducted with 12 new primary and secondary principals in Victoria, Australia as part of a longitudinal study from 1989 to 1993. This paper focuses on interview data collected during the first year of the study. Drawing from…

  5. Evaluating Principals. Research Roundup.

    ERIC Educational Resources Information Center

    Andrews, Carl

    1990-01-01

    Five recent studies included in this annotated bibliography highlight the diverse facets of an effective principal evaluation system. A technical report by Jerry W. Valentine and Michael L. Bowman includes a clinical instrument for assessing teachers' perception of principals' effectiveness. In a second report, Daniel L. Duke and Richard J.…

  6. Proteome analysis of the triton-insoluble erythrocyte membrane skeleton.

    PubMed

    Basu, Avik; Harper, Sandra; Pesciotta, Esther N; Speicher, Kaye D; Chakrabarti, Abhijit; Speicher, David W

    2015-10-14

    Erythrocyte shape and membrane integrity is imparted by the membrane skeleton, which can be isolated as a Triton X-100 insoluble structure that retains the biconcave shape of intact erythrocytes, indicating isolation of essentially intact membrane skeletons. These erythrocyte "Triton Skeletons" have been studied morphologically and biochemically, but unbiased proteome analysis of this substructure of the membrane has not been reported. In this study, different extraction buffers and in-depth proteome analyses were used to more fully define the protein composition of this functionally critical macromolecular complex. As expected, the major, well-characterized membrane skeleton proteins and their associated membrane anchors were recovered in good yield. But surprisingly, a substantial number of additional proteins that are not considered in erythrocyte membrane skeleton models were recovered in high yields, including myosin-9, lipid raft proteins (stomatin, flotillin1 and 2), multiple chaperone proteins (HSPs, protein disulfide isomerase and calnexin), and several other proteins. These results show that the membrane skeleton is substantially more complex than previous biochemical studies indicated, and it apparently has localized regions with unique protein compositions and functions. This comprehensive catalog of the membrane skeleton should lead to new insights into erythrocyte membrane biology and pathogenic mutations that perturb membrane stability. Biological significance Current models of erythrocyte membranes describe fairly simple homogenous structures that are incomplete. Proteome analysis of the erythrocyte membrane skeleton shows that it is quite complex and includes a substantial number of proteins whose roles and locations in the membrane are not well defined. Further elucidation of interactions involving these proteins and definition of microdomains in the membrane that contain these proteins should yield novel insights into how the membrane skeleton

  7. Proteome analysis of the triton-insoluble erythrocyte membrane skeleton.

    PubMed

    Basu, Avik; Harper, Sandra; Pesciotta, Esther N; Speicher, Kaye D; Chakrabarti, Abhijit; Speicher, David W

    2015-10-14

    Erythrocyte shape and membrane integrity is imparted by the membrane skeleton, which can be isolated as a Triton X-100 insoluble structure that retains the biconcave shape of intact erythrocytes, indicating isolation of essentially intact membrane skeletons. These erythrocyte "Triton Skeletons" have been studied morphologically and biochemically, but unbiased proteome analysis of this substructure of the membrane has not been reported. In this study, different extraction buffers and in-depth proteome analyses were used to more fully define the protein composition of this functionally critical macromolecular complex. As expected, the major, well-characterized membrane skeleton proteins and their associated membrane anchors were recovered in good yield. But surprisingly, a substantial number of additional proteins that are not considered in erythrocyte membrane skeleton models were recovered in high yields, including myosin-9, lipid raft proteins (stomatin, flotillin1 and 2), multiple chaperone proteins (HSPs, protein disulfide isomerase and calnexin), and several other proteins. These results show that the membrane skeleton is substantially more complex than previous biochemical studies indicated, and it apparently has localized regions with unique protein compositions and functions. This comprehensive catalog of the membrane skeleton should lead to new insights into erythrocyte membrane biology and pathogenic mutations that perturb membrane stability. Biological significance Current models of erythrocyte membranes describe fairly simple homogenous structures that are incomplete. Proteome analysis of the erythrocyte membrane skeleton shows that it is quite complex and includes a substantial number of proteins whose roles and locations in the membrane are not well defined. Further elucidation of interactions involving these proteins and definition of microdomains in the membrane that contain these proteins should yield novel insights into how the membrane skeleton

  8. Principal component analysis implementation in Java

    NASA Astrophysics Data System (ADS)

    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.

  9. Acid-Base and the Skeleton

    NASA Astrophysics Data System (ADS)

    Bushinsky, David A.

    2008-09-01

    Chronic metabolic acidosis increases urine calcium (Ca) excretion in the absence of a concomitant increase in intestinal Ca absorption resulting in a net loss of total body. The source of this additional urine Ca is almost certainly the skeleton, the primary reservoir of body Ca. In vitro metabolic acidosis, modeled as a primary reduction in medium bicarbonate concentration, acutely (<24 h) stimulates Ca efflux primarily through physicochemical mineral dissolution while at later time periods (>24 h) cell-mediated mechanisms predominate. In cultured neonatal mouse calvariae, acidosis-induced, cell-mediated Ca efflux is mediated by effects on both osteoblasts and osteoclasts. Metabolic acidosis inhibits extracellular matrix production by osteoblasts, as determined by measurement of collagen levels and levels for the non-collagenous matrix proteins osteopontin and matrix gla protein. Metabolic acidosis upregulates osteoblastic expression of RANKL (Receptor Activator of NFκB Ligand), an important osteoclastogenic and osteoclast-activating factor. Acidosis also increases osteoclastic activity as measured by release of β-glucuronidase, an enzyme whose secretion correlates with osteoclast-mediated bone resorption.

  10. Harmonic Skeleton Guided Evaluation of Stenoses in Human Coronary Arteries

    PubMed Central

    Yang, Yan; Zhu, Lei; Haker, Steven; Tannenbaum, Allen R.; Giddens, Don P.

    2013-01-01

    This paper presents a novel approach that three-dimensionally visualizes and evaluates stenoses in human coronary arteries by using harmonic skeletons. A harmonic skeleton is the center line of a multi-branched tubular surface extracted based on a harmonic function, which is the solution of the Laplace equation. This skeletonization method guarantees smoothness and connectivity and provides a fast and straightforward way to calculate local cross-sectional areas of the arteries, and thus provides the possibility to localize and evaluate coronary artery stenosis, which is a commonly seen pathology in coronary artery disease. PMID:16685882

  11. Harmonic skeleton guided evaluation of stenoses in human coronary arteries.

    PubMed

    Yang, Yan; Zhu, Lei; Haker, Steven; Tannenbaum, Allen R; Giddens, Don P

    2005-01-01

    This paper presents a novel approach that three-dimensionally visualizes and evaluates stenoses in human coronary arteries by using harmonic skeletons. A harmonic skeleton is the center line of a multi-branched tubular surface extracted based on a harmonic function, which is the solution of the Laplace equation. This skeletonization method guarantees smoothness and connectivity and provides a fast and straightforward way to calculate local cross-sectional areas of the arteries, and thus provides the possibility to localize and evaluate coronary artery stenosis, which is a commonly seen pathology in coronary artery disease. PMID:16685882

  12. Penetrating trauma to the facial skeleton by pickaxe - case report.

    PubMed

    Neskoromna-Jędrzejczak, Aneta; Bogusiak, Katarzyna; Przygoński, Aleksander; Timler, Dariusz

    2016-01-01

    Number of deaths related with injuries suffered as a result of experienced traumas is increasing. Penetrating traumas of the facial skeleton occur relatively rarely and much more often concern rather children than adults. Epidemiology relating this kind of trauma differs depending on the region of the world. In Poland, gunshot injuries as well as traumas caused by explosions of firecrackers or fireworks amount only to a slight percentage among all facial skeleton traumas, and the most common reason for penetrating traumas lies in accidents or assault with the use of sharp, narrow and long objects that easily enter bones of the facial skeleton. The present study reported the case of 50-year-old man who suffered from trauma of the facial skeleton, which resulted from foreign body (pickaxe) penetration into the subtemporal area, zygomatic arch and the right orbital cavity. The surgical treatment method and final outcome was presented and discussed. PMID:27096775

  13. 41. Ground level photograph of two floors of skeleton complete ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. Ground level photograph of two floors of skeleton complete with 3rd and 4th floors being started,upper floors of county bldg visible - Chicago City Hall, 121 North LaSalle Street, Chicago, Cook County, IL

  14. A method for finding three-dimensional magnetic skeletons

    SciTech Connect

    Haynes, A. L.; Parnell, C. E.

    2010-09-15

    Magnetic fields are an essential component of a plasma. In many astrophysical, solar, magnetospheric, and laboratory situations the magnetic field in the plasma can be very dynamic and form highly complex structures. One approach to unraveling these structures is to determine the magnetic skeleton of the field, a set of topological features that divide the magnetic field into topologically distinct domains. In general, the features of the magnetic skeleton are difficult to locate, in particular those given by numerical experiments. In this paper, we propose a new set of tools to find the skeleton of general magnetic fields including null points, spines, separatrix surfaces, and separators. This set of tools is found to be considerably better at finding the skeleton than the currently favored methods used in magnetohydrodynamics.

  15. Penetrating trauma to the facial skeleton by pickaxe - case report.

    PubMed

    Neskoromna-Jędrzejczak, Aneta; Bogusiak, Katarzyna; Przygoński, Aleksander; Timler, Dariusz

    2016-01-01

    Number of deaths related with injuries suffered as a result of experienced traumas is increasing. Penetrating traumas of the facial skeleton occur relatively rarely and much more often concern rather children than adults. Epidemiology relating this kind of trauma differs depending on the region of the world. In Poland, gunshot injuries as well as traumas caused by explosions of firecrackers or fireworks amount only to a slight percentage among all facial skeleton traumas, and the most common reason for penetrating traumas lies in accidents or assault with the use of sharp, narrow and long objects that easily enter bones of the facial skeleton. The present study reported the case of 50-year-old man who suffered from trauma of the facial skeleton, which resulted from foreign body (pickaxe) penetration into the subtemporal area, zygomatic arch and the right orbital cavity. The surgical treatment method and final outcome was presented and discussed.

  16. Effects of diabetes drugs on the skeleton.

    PubMed

    Meier, Christian; Schwartz, Ann V; Egger, Andrea; Lecka-Czernik, Beata

    2016-01-01

    Type 2 diabetes is associated with increased fracture risk and the mechanisms underlying the detrimental effects of diabetes on skeletal health are only partially understood. Antidiabetic drugs are indispensable for glycemic control in most type 2 diabetics, however, they may, at least in part, modulate fracture risk in exposed patients. Preclinical and clinical data clearly demonstrate an unfavorable effect of thiazolidinediones on the skeleton with impaired osteoblast function and activated osteoclastogenesis. The negative effect of thiazolidinediones on osteoblastogenesis includes decreased activity of osteoblast-specific transcription factors (e.g. Runx2, Dlx5, osterix) and decreased activity of osteoblast-specific signaling pathways (e.g. Wnt, TGF-β/BMP, IGF-1). In contrast, metformin has a positive effect on osteoblast differentiation due to increased activity of Runx2 via the AMPK/USF-1/SHP regulatory cascade resulting in a neutral or potentially protective effect on bone. Recently marketed antidiabetic drugs include incretin-based therapies (GLP-1 receptor agonists, DPP-4 inhibitors) and sodium-glucose co-transporter 2 (SGLT2)-inhibitors. Preclinical studies indicate that incretins (GIP, GLP-1, and GLP-2) play an important role in the regulation of bone turnover. Clinical safety data are limited, however, meta-analyses of trials investigating the glycemic-lowering effect of both, GLP-1 receptor agonists and DPP4-inhibitors, suggest a neutral effect of incretin-based therapies on fracture risk. For SGLT2-inhibitors recent data indicate that due to their mode of action they may alter calcium and phosphate homeostasis (secondary hyperparathyroidism induced by increased phosphate reabsorption) and thereby potentially affect bone mass and fracture risk. Clinical studies are needed to elucidate the effect of SGLT2-inhibitors on bone metabolism. Meanwhile SGLT2-inhibitors should be used with caution in patients with high fracture risk, which is specifically true

  17. The Skeleton of the Milky Way

    NASA Astrophysics Data System (ADS)

    Zucker, Catherine; Battersby, Cara; Goodman, Alyssa

    2015-12-01

    Recently, Goodman et al. argued that the very long, very thin infrared dark cloud “Nessie” lies directly in the Galactic midplane and runs along the Scutum-Centaurus Arm in position-position-velocity (p-p-v) space as traced by lower-density {{CO}} and higher-density {{NH}}3 gas. Nessie was presented as the first “bone” of the Milky Way, an extraordinarily long, thin, high-contrast filament that can be used to map our Galaxy’s “skeleton.” Here we present evidence for additional bones in the Milky Way, arguing that Nessie is not a curiosity but one of several filaments that could potentially trace Galactic structure. Our 10 bone candidates are all long, filamentary, mid-infrared extinction features that lie parallel to, and no more than 20 pc from, the physical Galactic mid-plane. We use {{CO}}, {{{N}}}2{{{H}}}+, {{{HCO}}}+, and {{NH}}3 radial velocity data to establish the three-dimensional location of the candidates in p-p-v space. Of the 10 candidates, 6 also have a projected aspect ratio of ≥50:1 run along, or extremely close to, the Scutum-Centaurus Arm in p-p-v space; and exhibit no abrupt shifts in velocity. The evidence presented here suggests that these candidates mark the locations of significant spiral features, with the bone called filament 5 (“BC_18.88-0.09”) being a close analog to Nessie in the northern sky. As molecular spectral-line and extinction maps cover more of the sky at increasing resolution and sensitivity, it should be possible to find more bones in future studies.

  18. Fracture occurrence from radionuclides in the skeleton

    SciTech Connect

    Lloyd, R.D.; Taylor, G.N.; Miller, S.C.

    2000-06-01

    Because skeletal fractures were an important finding among persons contaminated with {sup 226}Ra, experience with fractures among dogs in the colony was summarized to determine the projected significance for persons contaminated with bone-seeking radionuclides. Comparison by Fisher's Exact Test of lifetime fracture occurrence in the skeletons of beagles injected as young adults suggested that for animals given {sup 226}Ra, {sup 228}Ra, {sup 228}Th, or {sup 239}Pu citrate, there was probably an excess over controls in fractures of the ribs, leg bones, spinous processes, and pelvis (os coxae) plus the mandible for dogs given {sup 226}Ra and the scapulae for dogs given {sup 228}Ra or 228 Th. Regression analysis indicated that significantly elevated fracture occurrence was especially notable at the higher radiation doses, at about 50 Gy average skeletal dose for {sup 239}Pu, 140 Gy for {sup 226}Ra, about 40 Gy for {sup 228}Ra, and more than 15 Gy for {sup 228}Th. The average number of fractures per dog was significantly elevated over that noted in controls for the highest radiation doses of {sup 239}Pu and {sup 226}Ra and for the higher doses of {sup 228}Ra and {sup 228}Th. For those dogs given {sup 90}Sr citrate, there was virtually no important difference from control beagles not given radionuclides, even at group mean cumulative skeletal radiation doses up to 101 Gy. Because of a large proportion of dogs with fractures that died with bone malignancy (even at dosage levels lower than those exhibiting an excess average number of fractures per dog), they conclude that fracture would not be an important endpoint at lower levels of plutonium contamination in humans such as would be expected to occur from occupational or environmental exposure.

  19. PRINCIPAL ISOTOPE SELECTION REPORT

    SciTech Connect

    K. D. Wright

    1998-08-28

    Utilizing nuclear fuel to produce power in commercial reactors results in the production of hundreds of fission product and transuranic isotopes in the spent nuclear fuel (SNF). When the SNF is disposed of in a repository, the criticality analyses could consider all of the isotopes, some principal isotopes affecting criticality, or none of the isotopes, other than the initial loading. The selected set of principal isotopes will be the ones used in criticality analyses of the SNF to evaluate the reactivity of the fuel/waste package composition and configuration. This technical document discusses the process used to select the principal isotopes and the possible affect that these isotopes could have on criticality in the SNF. The objective of this technical document is to discuss the process used to select the principal isotopes for disposal criticality evaluations with commercial SNF. The principal isotopes will be used as supporting information in the ''Disposal Criticality Analysis Methodology Topical Report'' which will be presented to the United States Nuclear Regulatory Commission (NRC) when approved by the United States Department of Energy (DOE) Office of Civilian Radioactive Waste Management (OCRWM).

  20. Interpretable functional principal component analysis.

    PubMed

    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.

  1. Automated characterization of cell shape changes during amoeboid motility by skeletonization

    PubMed Central

    2010-01-01

    Background The ability of a cell to change shape is crucial for the proper function of many cellular processes, including cell migration. One type of cell migration, referred to as amoeboid motility, involves alternating cycles of morphological expansion and retraction. Traditionally, this process has been characterized by a number of parameters providing global information about shape changes, which are insufficient to distinguish phenotypes based on local pseudopodial activities that typify amoeboid motility. Results We developed a method that automatically detects and characterizes pseudopodial behavior of cells. The method uses skeletonization, a technique from morphological image processing to reduce a shape into a series of connected lines. It involves a series of automatic algorithms including image segmentation, boundary smoothing, skeletonization and branch pruning, and takes into account the cell shape changes between successive frames to detect protrusion and retraction activities. In addition, the activities are clustered into different groups, each representing the protruding and retracting history of an individual pseudopod. Conclusions We illustrate the algorithms on movies of chemotaxing Dictyostelium cells and show that our method makes it possible to capture the spatial and temporal dynamics as well as the stochastic features of the pseudopodial behavior. Thus, the method provides a powerful tool for investigating amoeboid motility. PMID:20334652

  2. Principal Instructional Leadership.

    ERIC Educational Resources Information Center

    Short, Paula M.; Spencer, William A.

    Although the literature points to principals' central role in enhancing school effectiveness, the demonstration of a causal relationship between their instructional leadership and student achievement is difficult. Researchers have suggested that instructional leadership can influence teaching and classroom practices through the establishment of…

  3. Effective Principals in Action

    ERIC Educational Resources Information Center

    Spiro, Jody D.

    2013-01-01

    The idea that principals should focus more closely on teaching and learning did not emerge prominently until the mid-1990s. Then educators and policy makers began to realize that school leadership matters to student achievement. In a dozen years of working with states, districts, researchers and others, the Wallace Foundation has pinpointed five…

  4. Support Principals, Transform Schools

    ERIC Educational Resources Information Center

    Aguilar, Elena; Goldwasser, Davina; Tank-Crestetto, Kristina

    2011-01-01

    The Transformational Coaching Team in Oakland Unified School District provides differentiated, sustained, job-embedded support to the district's school leaders. In this article, members of the team describe how they work with principals to transform the culture of schools. Student achievement data show above-average improvement in schools in which…

  5. When Principals Gather.

    ERIC Educational Resources Information Center

    Trotter, Andrew

    1992-01-01

    Summarizes main discussion topics at the recent annual meeting of the National Association of Elementary School Principals held in New Orleans. Participants discussed school readiness, parenthood education, minority achievement, whole-language instruction, and multiculturalism. The Association for Supervision and Curriculum Development's New…

  6. Let Teachers Pick Principals.

    ERIC Educational Resources Information Center

    Raisch, C. Daniel

    1993-01-01

    If a school and community are qualified enough to hire teachers, counselors, and secretaries through school-based-management processes, they are equally qualified to hire the school principal. This article describes a site-based team-selection process designed to identify optimal administrator characteristics, advertise the job opening, handle…

  7. Principals Make Assignments Matter

    ERIC Educational Resources Information Center

    Dougherty, Eleanor

    2013-01-01

    The inner-city high school in Washington, DC, that Guillaume Gendre joined as an assistant principal had a modest reputation for achievement but was nevertheless challenged to raise expectations for student work. In other schools, Gendre had used assignments--a specific kind of instructional task in which students are charged to think about an…

  8. Preparing Future Principals

    ERIC Educational Resources Information Center

    Whitaker, Kathryn

    2006-01-01

    Nationwide, school district administrators are puzzling about how to increase the number of high quality principal candidates. Some districts have started programs to grow their own administrators. These districts, sometimes in conjunction with university programs, are providing training and mentoring for future school leaders. Some districts are…

  9. Principals as Cultural Leaders

    ERIC Educational Resources Information Center

    Louis, Karen Seashore; Wahlstrom, Kyla

    2011-01-01

    Principals have a strong role to play in forming school cultures that encourage change. Changing a school's culture requires shared or distributed leadership and instructional leadership. A multiyear study found that three elements are necessary for a school culture that stimulates teachers to improve their instruction: 1) Teachers and…

  10. Developing Emotionally Intelligent Principals

    ERIC Educational Resources Information Center

    Cox, Edward P.

    2009-01-01

    Transformational change in today's schools will require leaders with strong intrapersonal and interpersonal skills. A recent assessment program in South Carolina focused attention on the identification of the emotional intelligence of aspiring and newly appointed principals. A battery of personality and leadership assessments was used to develop…

  11. The Principal as CEO

    ERIC Educational Resources Information Center

    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…

  12. Mentoring Women Principals

    ERIC Educational Resources Information Center

    Arthur, Cheryl A.; Salsberry, Trudy A.

    2005-01-01

    This review of the literature focuses first on the common reasons for the need for mentoring (professional development, changing roles, principal shortage, under representation of women, and barriers) and continues with a definition and description of mentoring. Finally, the current status of mentoring is summarized followed by a discussion of the…

  13. Revisiting scoliosis in the KNM-WT 15000 Homo erectus skeleton.

    PubMed

    Schiess, Regula; Boeni, Thomas; Rühli, Frank; Haeusler, Martin

    2014-02-01

    Owing to its completeness, the 1.5 million year old Nariokotome boy skeleton KNM-WT 15000 is central for understanding the skeletal biology of Homo erectus. Nevertheless, since the reported asymmetries and distortions of Nariokotome boy's axial skeleton suggest adolescent idiopathic scoliosis, possibly associated with congenital skeletal dysplasia, it is questionable whether it still can be used as a reference for H. erectus. Recently, however, the presence of skeletal dysplasia has been refuted. Here, we present a morphological and morphometric reanalysis of the assertion of idiopathic scoliosis. We demonstrate that unarticulated vertebral columns of non-scoliotic and scoliotic individuals can be distinguished based on the lateral deviation of the spinous process, lateral and sagittal wedging, vertebral body torsion, pedicle thickness asymmetry, and asymmetry of superior and inferior articular facet areas. A principal component analysis of the overall asymmetry of all seven vertebral shape variables groups KNM-WT 15000 within non-scoliotic modern humans. There is, however, an anomaly of vertebrae T1-T2 that is compatible with a short left convex curve at the uppermost thoracic region, possibly due to injury or local growth dysbalance. Asymmetries of the facet joints L3-L5 suggest a local right convex curve in the lower lumbar region that probably resulted from juvenile traumatic disc herniation. This pattern is incompatible with adolescent idiopathic scoliosis or other types of scoliosis, including congenital, neuromuscular or syndromic scoliosis. It is, however, consistent with a recent reanalysis of the rib cage that did not reveal any asymmetry. Except for these possibly trauma-related anomalies, the Nariokotome boy fossil therefore seems to belong to a normal H. erectus youth without evidence for adolescent idiopathic scoliosis or other severe pathologies of the axial skeleton. PMID:24491377

  14. Computational tool for phase-shift calculation in an interference pattern by fringe displacements based on a skeletonized image

    NASA Astrophysics Data System (ADS)

    Rivera-Ortega, Uriel; Pico-Gonzalez, Beatriz

    2016-01-01

    In this manuscript an algorithm based on a graphic user interface (GUI) designed in MATLAB for an automatic phase-shifting estimation between two digitalized interferograms is presented. The proposed algorithm finds the midpoint locus of the dark and bright interference fringes in two skeletonized fringe patterns and relates their displacements with the corresponding phase-shift. In order to demonstrate the usefulness of the proposed GUI, its application to simulated and experimental interference patterns will be shown. The viability of this GUI makes it a helpful and easy-to-use computational tool for educational or research purposes in optical phenomena for undergraduate or graduate studies in the field of physics.

  15. Segmentation and Visual Analysis of Whole-Body Mouse Skeleton microSPECT

    PubMed Central

    Khmelinskii, Artem; Groen, Harald C.; Baiker, Martin; de Jong, Marion; Lelieveldt, Boudewijn P. F.

    2012-01-01

    Whole-body SPECT small animal imaging is used to study cancer, and plays an important role in the development of new drugs. Comparing and exploring whole-body datasets can be a difficult and time-consuming task due to the inherent heterogeneity of the data (high volume/throughput, multi-modality, postural and positioning variability). The goal of this study was to provide a method to align and compare side-by-side multiple whole-body skeleton SPECT datasets in a common reference, thus eliminating acquisition variability that exists between the subjects in cross-sectional and multi-modal studies. Six whole-body SPECT/CT datasets of BALB/c mice injected with bone targeting tracers 99mTc-methylene diphosphonate (99mTc-MDP) and 99mTc-hydroxymethane diphosphonate (99mTc-HDP) were used to evaluate the proposed method. An articulated version of the MOBY whole-body mouse atlas was used as a common reference. Its individual bones were registered one-by-one to the skeleton extracted from the acquired SPECT data following an anatomical hierarchical tree. Sequential registration was used while constraining the local degrees of freedom (DoFs) of each bone in accordance to the type of joint and its range of motion. The Articulated Planar Reformation (APR) algorithm was applied to the segmented data for side-by-side change visualization and comparison of data. To quantitatively evaluate the proposed algorithm, bone segmentations of extracted skeletons from the correspondent CT datasets were used. Euclidean point to surface distances between each dataset and the MOBY atlas were calculated. The obtained results indicate that after registration, the mean Euclidean distance decreased from 11.5±12.1 to 2.6±2.1 voxels. The proposed approach yielded satisfactory segmentation results with minimal user intervention. It proved to be robust for “incomplete” data (large chunks of skeleton missing) and for an intuitive exploration and comparison of multi-modal SPECT/CT cross

  16. Taphonomy of the Tianyuandong human skeleton and faunal remains.

    PubMed

    Fernández-Jalvo, Yolanda; Andrews, Peter; Tong, HaoWen

    2015-06-01

    Tianyuan Cave is an Upper Palaeolithic site, 6 km from the core area of the Zhoukoudian Site Complex. Tianyuandong (or Tianyuan Cave) yielded one ancient (though not the earliest) fossil skeleton of Homo sapiens in China (42-39 ka cal BP). Together with the human skeleton, abundant animal remains were found, but no stone tools were recovered. The animal fossil remains are extremely fragmentary, in contrast to human skeletal elements that are, for the most part, complete. We undertook a taphonomic study to investigate the circumstances of preservation of the human skeleton in Tianyuan Cave, and in course of this we considered four hypotheses: funerary ritual, cannibalism, carnivore activity or natural death. Taphonomic results characterize the role of human action in the site and how these agents acted in the past. Because of disturbance of the human skeleton during its initial excavation, it is not known if it was in a grave cut or if there was any funerary ritual. No evidence was found for cannibalism or carnivore activity in relation to the human skeleton, suggesting natural death as the most reasonable possibility. PMID:25929706

  17. Taphonomy of the Tianyuandong human skeleton and faunal remains.

    PubMed

    Fernández-Jalvo, Yolanda; Andrews, Peter; Tong, HaoWen

    2015-06-01

    Tianyuan Cave is an Upper Palaeolithic site, 6 km from the core area of the Zhoukoudian Site Complex. Tianyuandong (or Tianyuan Cave) yielded one ancient (though not the earliest) fossil skeleton of Homo sapiens in China (42-39 ka cal BP). Together with the human skeleton, abundant animal remains were found, but no stone tools were recovered. The animal fossil remains are extremely fragmentary, in contrast to human skeletal elements that are, for the most part, complete. We undertook a taphonomic study to investigate the circumstances of preservation of the human skeleton in Tianyuan Cave, and in course of this we considered four hypotheses: funerary ritual, cannibalism, carnivore activity or natural death. Taphonomic results characterize the role of human action in the site and how these agents acted in the past. Because of disturbance of the human skeleton during its initial excavation, it is not known if it was in a grave cut or if there was any funerary ritual. No evidence was found for cannibalism or carnivore activity in relation to the human skeleton, suggesting natural death as the most reasonable possibility.

  18. The Texting Principal

    ERIC Educational Resources Information Center

    Kessler, Susan Stone

    2009-01-01

    The author was appointed principal of a large, urban comprehensive high school in spring 2008. One of the first things she had to figure out was how she would develop a connection with her students when there were so many of them--nearly 2,000--and only one of her. Texts may be exchanged more quickly than having a conversation over the phone,…

  19. A vanished history of skeletonization in Cambrian comb jellies.

    PubMed

    Ou, Qiang; Xiao, Shuhai; Han, Jian; Sun, Ge; Zhang, Fang; Zhang, Zhifei; Shu, Degan

    2015-07-01

    Ctenophores are traditionally regarded as "lower" metazoans, sharing with cnidarians a diploblastic grade of organization. Unlike cnidarians, where skeletonization (biomineralization and sclerotization) evolved repeatedly among ecologically important taxa (for example, scleractinians and octocorals), living ctenophores are characteristically soft-bodied animals. We report six sclerotized and armored ctenophores from the early Cambrian period. They have diagnostic ctenophore features (for example, an octamerous symmetry, oral-aboral axis, aboral sense organ, and octaradially arranged ctene rows). Unlike most modern counterparts, however, they lack tentacles, have a sclerotized framework, and have eight pairs of ctene rows. They are resolved as a monophyletic group (Scleroctenophora new class) within the ctenophores. This clade reveals a cryptic history and sheds new light on the early evolution of this basal animal phylum. Skeletonization also occurs in some other Cambrian animal groups whose extant members are exclusively soft-bodied, suggesting the ecological importance of skeletonization in the Cambrian explosion. PMID:26601209

  20. A vanished history of skeletonization in Cambrian comb jellies

    PubMed Central

    Ou, Qiang; Xiao, Shuhai; Han, Jian; Sun, Ge; Zhang, Fang; Zhang, Zhifei; Shu, Degan

    2015-01-01

    Ctenophores are traditionally regarded as “lower” metazoans, sharing with cnidarians a diploblastic grade of organization. Unlike cnidarians, where skeletonization (biomineralization and sclerotization) evolved repeatedly among ecologically important taxa (for example, scleractinians and octocorals), living ctenophores are characteristically soft-bodied animals. We report six sclerotized and armored ctenophores from the early Cambrian period. They have diagnostic ctenophore features (for example, an octamerous symmetry, oral-aboral axis, aboral sense organ, and octaradially arranged ctene rows). Unlike most modern counterparts, however, they lack tentacles, have a sclerotized framework, and have eight pairs of ctene rows. They are resolved as a monophyletic group (Scleroctenophora new class) within the ctenophores. This clade reveals a cryptic history and sheds new light on the early evolution of this basal animal phylum. Skeletonization also occurs in some other Cambrian animal groups whose extant members are exclusively soft-bodied, suggesting the ecological importance of skeletonization in the Cambrian explosion. PMID:26601209

  1. [Study of the skeleton of Admiral F. F. Ushakov].

    PubMed

    Zviagin, V N; Ivanov, N V; Narina, N V

    2002-01-01

    Reports the results of examination of the skeleton of Admiral F. F. Ushakov, carried out in connection with canonization in the Russian Orthodox Church. Heretofore unknown data on the somatic characteristics of F. F. Ushakov and his diseases are presented. Special attention is paid to uneven age involution of the skeleton and the hypoergic aging velocity. A detailed morphological similarity between the skulls of F. F. Ushakov and monk Feodor (Admiral's uncle, I. I. Ushakov) evidenced common features inherited through the masculine line. Modern computer technologies showed that the appearance of F. F. Ushakov, determined by the skull and postcranial skeleton, agree with his appearance on the life-time portrait, in spite of Professor M. M. Gerasimov's opinion (1949). In this connection, the possibility of repeated reconstruction of Admiral Ushakov's appearance is proven. PMID:12063793

  2. Chemical transformations on botryane skeleton. Effect on the cytotoxic activity.

    PubMed

    Reino, José L; Durán-Patrón, Rosa; Segura, Inmaculada; Hernández-Galán, Rosario; Riese, Hans H; Collado, Isidro G

    2003-03-01

    Eighteen compounds with a botryane skeleton have been obtained through chemical transformations of various toxins from the fungus Botrytis cinerea. During the course of these transformations, the C-10 carbon of the botryane skeleton was found to exhibit an interesting high regioselectivity to oxidizing and reducing agents. In addition, the cytotoxicity of 27 botryane derivatives was determined in vitro against Hs578T, MDA-MB-231, HT-1080, U87-MG, IMR-90, and HUVEC cell lines. The results of this study confirm that the cytotoxicity of botrydial (1) and its derivatives is related to the presence of a 1,5-dialdehyde functionality.

  3. Anatomy-based 3D skeleton extraction from femur model.

    PubMed

    Gharenazifam, Mina; Arbabi, Ehsan

    2014-11-01

    Using 3D models of bones can highly improve accuracy and reliability of orthopaedic evaluation. However, it may impose excessive computational load. This article proposes a fully automatic method for extracting a compact model of the femur from its 3D model. The proposed method works by extracting a 3D skeleton based on the clinical parameters of the femur. Therefore, in addition to summarizing a 3D model of the bone, the extracted skeleton would preserve important clinical and anatomical information. The proposed method has been applied on 3D models of 10 femurs and the results have been evaluated for different resolutions of data.

  4. Synthesis of Novel Basic Skeletons Derived from Naltrexone

    NASA Astrophysics Data System (ADS)

    Nagase, Hiroshi; Fujii, Hideaki

    We will describe eight interesting reactions using naltrexone derivatives. Almost all these reactions are characteristic of naltrexone derivatives, and can lead to the synthesis of many novel skeletons that provide new interesting pharmacological data. Some of the new reactions that were found with naltrexone derivatives were expanded into general reactions. For example, the reaction of 6α-hydroxyaldehyde derived from naltrexone led to the oxazoline dimer and the 1,3,5-trioxazatriquinane skeleton (triplet drug); this reaction was applied to general ketones which were converted to α-hydroxyaldehydes, followed by conversion to dimers and trimers, as described in Sect. 7.

  5. Shedding Light on the Cosmic Skeleton

    NASA Astrophysics Data System (ADS)

    2009-11-01

    Astronomers have tracked down a gigantic, previously unknown assembly of galaxies located almost seven billion light-years away from us. The discovery, made possible by combining two of the most powerful ground-based telescopes in the world, is the first observation of such a prominent galaxy structure in the distant Universe, providing further insight into the cosmic web and how it formed. "Matter is not distributed uniformly in the Universe," says Masayuki Tanaka from ESO, who led the new study. "In our cosmic vicinity, stars form in galaxies and galaxies usually form groups and clusters of galaxies. The most widely accepted cosmological theories predict that matter also clumps on a larger scale in the so-called 'cosmic web', in which galaxies, embedded in filaments stretching between voids, create a gigantic wispy structure." These filaments are millions of light years long and constitute the skeleton of the Universe: galaxies gather around them, and immense galaxy clusters form at their intersections, lurking like giant spiders waiting for more matter to digest. Scientists are struggling to determine how they swirl into existence. Although massive filamentary structures have been often observed at relatively small distances from us, solid proof of their existence in the more distant Universe has been lacking until now. The team led by Tanaka discovered a large structure around a distant cluster of galaxies in images they obtained earlier. They have now used two major ground-based telescopes to study this structure in greater detail, measuring the distances from Earth of over 150 galaxies, and, hence, obtaining a three-dimensional view of the structure. The spectroscopic observations were performed using the VIMOS instrument on ESO's Very Large Telescope and FOCAS on the Subaru Telescope, operated by the National Astronomical Observatory of Japan. Thanks to these and other observations, the astronomers were able to make a real demographic study of this structure

  6. Online kernel principal component analysis: a reduced-order model.

    PubMed

    Honeine, Paul

    2012-09-01

    Kernel principal component analysis (kernel-PCA) is an elegant nonlinear extension of one of the most used data analysis and dimensionality reduction techniques, the principal component analysis. In this paper, we propose an online algorithm for kernel-PCA. To this end, we examine a kernel-based version of Oja's rule, initially put forward to extract a linear principal axe. As with most kernel-based machines, the model order equals the number of available observations. To provide an online scheme, we propose to control the model order. We discuss theoretical results, such as an upper bound on the error of approximating the principal functions with the reduced-order model. We derive a recursive algorithm to discover the first principal axis, and extend it to multiple axes. Experimental results demonstrate the effectiveness of the proposed approach, both on synthetic data set and on images of handwritten digits, with comparison to classical kernel-PCA and iterative kernel-PCA.

  7. Macro-anatomical investigations on the skeletons of porcupine (Hystrix cristata). Part III: skeleton axiale.

    PubMed

    Yilmaz, S

    1998-10-01

    The aim of this study was to investigate the axial skeleton of two porcupines (Hystrix cristata). The important features of the skull, observed in this study are as follows: The zygomatic process of frontal bone (os frontal) was found to be rudimentary, and the infraorbital foramen (for. infraorbitale) was very large. The zygomatic bone (os zygomaticum) has two processes (frontal and temporal) and the zygomatic arch (arcus zygomaticum) was composed of three bones. The dental formulae were 2 (I 1/1, C 0/0, P 1/1, M 3/3) = 20. The angular process (Proc. angularis) of mandible is well developed. The vertebral formula was found as C7, T15, L4, S4, Ca12. All of cervical vertebrae had the transverse foramen (for. transversarium). The first eleven spinous processes (proc. spinosus) of thoracic vertebrae were caudally-sloped, the twelfth as the anticlin vertebrae and the last three were directed cranially. Hemal arches (or ossa arcus hemalis) were presented as separate bones which articulate with the ventral surfaces of the caudal ends of the bodies of the second, third and fourth caudal vertebrae.

  8. Principals and Vice-Principals. Bibliographies in Education No. 65.

    ERIC Educational Resources Information Center

    Dohan, Margaret

    This bibliography lists material published on principals and vice-principals since March 1975. The entries include 215 books, 437 articles, and 6 theses. A list is provided of the Federation's publications in this series. (JM)

  9. A Human Activity Recognition System Using Skeleton Data from RGBD Sensors

    PubMed Central

    Gasparrini, Samuele

    2016-01-01

    The aim of Active and Assisted Living is to develop tools to promote the ageing in place of elderly people, and human activity recognition algorithms can help to monitor aged people in home environments. Different types of sensors can be used to address this task and the RGBD sensors, especially the ones used for gaming, are cost-effective and provide much information about the environment. This work aims to propose an activity recognition algorithm exploiting skeleton data extracted by RGBD sensors. The system is based on the extraction of key poses to compose a feature vector, and a multiclass Support Vector Machine to perform classification. Computation and association of key poses are carried out using a clustering algorithm, without the need of a learning algorithm. The proposed approach is evaluated on five publicly available datasets for activity recognition, showing promising results especially when applied for the recognition of AAL related actions. Finally, the current applicability of this solution in AAL scenarios and the future improvements needed are discussed. PMID:27069469

  10. A Human Activity Recognition System Using Skeleton Data from RGBD Sensors.

    PubMed

    Cippitelli, Enea; Gasparrini, Samuele; Gambi, Ennio; Spinsante, Susanna

    2016-01-01

    The aim of Active and Assisted Living is to develop tools to promote the ageing in place of elderly people, and human activity recognition algorithms can help to monitor aged people in home environments. Different types of sensors can be used to address this task and the RGBD sensors, especially the ones used for gaming, are cost-effective and provide much information about the environment. This work aims to propose an activity recognition algorithm exploiting skeleton data extracted by RGBD sensors. The system is based on the extraction of key poses to compose a feature vector, and a multiclass Support Vector Machine to perform classification. Computation and association of key poses are carried out using a clustering algorithm, without the need of a learning algorithm. The proposed approach is evaluated on five publicly available datasets for activity recognition, showing promising results especially when applied for the recognition of AAL related actions. Finally, the current applicability of this solution in AAL scenarios and the future improvements needed are discussed.

  11. The origin of a new fin skeleton through tinkering.

    PubMed

    Stewart, Thomas A

    2015-07-01

    Adipose fins are positioned between the dorsal and caudal fins of many teleost fishes and primitively lack skeleton. In at least four lineages, adipose fins have evolved lepidotrichia (bony fin rays), co-opting the developmental programme for the dermal skeleton of other fins into this new territory. Here I provide, to my knowledge, the first description of lepidotrichia development in an adipose fin, characterizing the ontogeny of the redtail catfish, Phractocephalus hemioliopterus. Development of these fin rays differs from canonical lepidotrich development in the following four ways: skeleton begins developing in adults, not in larvae; rays begin developing at the fin's distal tip, not proximally; the order in which rays ossify is variable, not fixed; and lepidotrichia appear to grow both proximally and distally, not exclusively proximodistally. Lepidotrichia are often wavy, of irregular thickness and exhibit no regular pattern of segmentation or branching. This skeleton is among the most variable observed in a vertebrate appendage, offering a unique opportunity to explore the basis of hypervariation, which is generally assumed to reflect an absence of function. I argue that this variation reflects a lack of canalization as compared with other, more ancient lepidotrichs and suggest developmental context can affect the morphology of serial homologues. PMID:26179803

  12. A practical introduction to skeletons for the plant sciences1

    PubMed Central

    Bucksch, Alexander

    2014-01-01

    Before the availability of digital photography resulting from the invention of charged couple devices in 1969, the measurement of plant architecture was a manual process either on the plant itself or on traditional photographs. The introduction of cheap digital imaging devices for the consumer market enabled the wide use of digital images to capture the shape of plant networks such as roots, tree crowns, or leaf venation. Plant networks contain geometric traits that can establish links to genetic or physiological characteristics, support plant breeding efforts, drive evolutionary studies, or serve as input to plant growth simulations. Typically, traits are encoded in shape descriptors that are computed from imaging data. Skeletons are one class of shape descriptors that are used to describe the hierarchies and extent of branching and looping plant networks. While the mathematical understanding of skeletons is well developed, their application within the plant sciences remains challenging because the quality of the measurement depends partly on the interpretation of the skeleton. This article is meant to bridge the skeletonization literature in the plant sciences and related technical fields by discussing best practices for deriving diameters and approximating branching hierarchies in a plant network. PMID:25202645

  13. The origin of a new fin skeleton through tinkering

    PubMed Central

    Stewart, Thomas A.

    2015-01-01

    Adipose fins are positioned between the dorsal and caudal fins of many teleost fishes and primitively lack skeleton. In at least four lineages, adipose fins have evolved lepidotrichia (bony fin rays), co-opting the developmental programme for the dermal skeleton of other fins into this new territory. Here I provide, to my knowledge, the first description of lepidotrichia development in an adipose fin, characterizing the ontogeny of the redtail catfish, Phractocephalus hemioliopterus. Development of these fin rays differs from canonical lepidotrich development in the following four ways: skeleton begins developing in adults, not in larvae; rays begin developing at the fin's distal tip, not proximally; the order in which rays ossify is variable, not fixed; and lepidotrichia appear to grow both proximally and distally, not exclusively proximodistally. Lepidotrichia are often wavy, of irregular thickness and exhibit no regular pattern of segmentation or branching. This skeleton is among the most variable observed in a vertebrate appendage, offering a unique opportunity to explore the basis of hypervariation, which is generally assumed to reflect an absence of function. I argue that this variation reflects a lack of canalization as compared with other, more ancient lepidotrichs and suggest developmental context can affect the morphology of serial homologues. PMID:26179803

  14. The ocular skeleton through the eye of evo-devo.

    PubMed

    Franz-Odendaal, Tamara Anne

    2011-09-15

    An evolutionary developmental (evo-devo) approach to understanding the evolution, homology, and development of structures has proved important for unraveling complex integrated skeletal systems through the use of modules, or modularity. An ocular skeleton, which consists of cartilage and sometimes bone, is present in many vertebrates; however, the origin of these two components remains elusive. Using both paleontological and developmental data, I propose that the vertebrate ocular skeleton is neural crest derived and that a single cranial neural crest module divided early in vertebrate evolution, possibly during the Ordovician, to give rise to an endoskeletal component and an exoskeletal component within the eye. These two components subsequently became uncoupled with respect to timing, placement within the sclera and inductive epithelia, enabling them to evolve independently and to diversify. In some extant groups, these two modules have become reassociated with one another. Furthermore, the data suggest that the endoskeletal component of the ocular skeleton was likely established and therefore evolved before the exoskeletal component. This study provides important insights into the evolution of the ocular skeleton, a region with a long evolutionary history among vertebrates.

  15. The origin of a new fin skeleton through tinkering.

    PubMed

    Stewart, Thomas A

    2015-07-01

    Adipose fins are positioned between the dorsal and caudal fins of many teleost fishes and primitively lack skeleton. In at least four lineages, adipose fins have evolved lepidotrichia (bony fin rays), co-opting the developmental programme for the dermal skeleton of other fins into this new territory. Here I provide, to my knowledge, the first description of lepidotrichia development in an adipose fin, characterizing the ontogeny of the redtail catfish, Phractocephalus hemioliopterus. Development of these fin rays differs from canonical lepidotrich development in the following four ways: skeleton begins developing in adults, not in larvae; rays begin developing at the fin's distal tip, not proximally; the order in which rays ossify is variable, not fixed; and lepidotrichia appear to grow both proximally and distally, not exclusively proximodistally. Lepidotrichia are often wavy, of irregular thickness and exhibit no regular pattern of segmentation or branching. This skeleton is among the most variable observed in a vertebrate appendage, offering a unique opportunity to explore the basis of hypervariation, which is generally assumed to reflect an absence of function. I argue that this variation reflects a lack of canalization as compared with other, more ancient lepidotrichs and suggest developmental context can affect the morphology of serial homologues.

  16. Learning about Skeletons and Other Organ Systems of Vertebrate Animals.

    ERIC Educational Resources Information Center

    Tunnicliffe, Sue Dale; Reiss, Michael

    1999-01-01

    Describes students' (n=175) understandings of the structure of animal (including human) skeletons and the internal organs found in them. Finds that older students have a better knowledge of animals' internal anatomies, although knowledge of human internal structure is significantly better than knowledge of rat, bird, and fish internal structure.…

  17. Algorithms and Algorithmic Languages.

    ERIC Educational Resources Information Center

    Veselov, V. M.; Koprov, V. M.

    This paper is intended as an introduction to a number of problems connected with the description of algorithms and algorithmic languages, particularly the syntaxes and semantics of algorithmic languages. The terms "letter, word, alphabet" are defined and described. The concept of the algorithm is defined and the relation between the algorithm and…

  18. Visible Leading: Principal Academy Connects and Empowers Principals

    ERIC Educational Resources Information Center

    Hindman, Jennifer; Rozzelle, Jan; Ball, Rachel; Fahey, John

    2015-01-01

    The School-University Research Network (SURN) Principal Academy at the College of William & Mary in Williamsburg, Virginia, has a mission to build a leadership development program that increases principals' instructional knowledge and develops mentor principals to sustain the program. The academy is designed to connect and empower principals…

  19. Teacher and Principal Beliefs about Principal Leadership Behavior

    ERIC Educational Resources Information Center

    Morris, Mary Beth

    2011-01-01

    The purpose of this study was to examine whether or not there is a difference between teacher and principal beliefs about principal leadership behavior using a 360-degree evaluation tool. The study also examined whether the difference between teacher and principal beliefs was related to the status of a school relative to the state growth target…

  20. Principals' Supervision and Evaluation Cycles: Perspectives from Principals

    ERIC Educational Resources Information Center

    Hvidston, David J.; McKim, Courtney Ann; Mette, Ian M.

    2016-01-01

    The goals for this quantitative study were to examine principals' perceptions regarding supervision and evaluation within their own evaluations. Three research questions guided the inquiry: (1) What are the perceptions of principals' regarding their own supervision?; (2) What are the perceptions of principals' regarding their own evaluation?; and…

  1. The skeleton of postmetamorphic echinoderms in a changing world.

    PubMed

    Dubois, Philippe

    2014-06-01

    Available evidence on the impact of acidification and its interaction with warming on the skeleton of postmetamorphic (juvenile and adult) echinoderms is reviewed. Data are available on sea urchins, starfish, and brittle stars in 33 studies. Skeleton growth of juveniles of all sea urchin species studied so far is affected from pH 7.8 to 7.6 in seawater, values that are expected to be reached during the 21st century. Growth in adult sea urchins (six species studied) is apparently only marginally affected at seawater pH relevant to this century. The interacting effect of temperature differed according to studies. Juvenile starfish as well as adults seem to be either not impacted or even boosted by acidification. Brittle stars show moderate effects at pH below or equal to 7.4. Dissolution of the body wall skeleton is unlikely to be a major threat to sea urchins. Spines, however, due to their exposed position, are more prone to this threat, but their regeneration abilities can probably ensure their maintenance, although this could have an energetic cost and induce changes in resource allocation. No information is available on skeleton dissolution in starfish, and the situation in brittle stars needs further assessment. Very preliminary evidence indicates that mechanical properties in sea urchins could be affected. So, although the impact of ocean acidification on the skeleton of echinoderms has been considered as a major threat from the first studies, we need a better understanding of the induced changes, in particular the functional consequences of growth modifications and dissolution related to mechanical properties. It is suggested to focus studies on these aspects.

  2. Ocean acidification and warming scenarios increase microbioerosion of coral skeletons.

    PubMed

    Reyes-Nivia, Catalina; Diaz-Pulido, Guillermo; Kline, David; Guldberg, Ove-Hoegh; Dove, Sophie

    2013-06-01

    Biological mediation of carbonate dissolution represents a fundamental component of the destructive forces acting on coral reef ecosystems. Whereas ocean acidification can increase dissolution of carbonate substrates, the combined impact of ocean acidification and warming on the microbioerosion of coral skeletons remains unknown. Here, we exposed skeletons of the reef-building corals, Porites cylindrica and Isopora cuneata, to present-day (Control: 400 μatm - 24 °C) and future pCO2 -temperature scenarios projected for the end of the century (Medium: +230 μatm - +2 °C; High: +610 μatm - +4 °C). Skeletons were also subjected to permanent darkness with initial sodium hypochlorite incubation, and natural light without sodium hypochlorite incubation to isolate the environmental effect of acidic seawater (i.e., Ωaragonite <1) from the biological effect of photosynthetic microborers. Our results indicated that skeletal dissolution is predominantly driven by photosynthetic microborers, as samples held in the dark did not decalcify. In contrast, dissolution of skeletons exposed to light increased under elevated pCO2 -temperature scenarios, with P. cylindrica experiencing higher dissolution rates per month (89%) than I. cuneata (46%) in the high treatment relative to control. The effects of future pCO2 -temperature scenarios on the structure of endolithic communities were only identified in P. cylindrica and were mostly associated with a higher abundance of the green algae Ostreobium spp. Enhanced skeletal dissolution was also associated with increased endolithic biomass and respiration under elevated pCO2 -temperature scenarios. Our results suggest that future projections of ocean acidification and warming will lead to increased rates of microbioerosion. However, the magnitude of bioerosion responses may depend on the structural properties of coral skeletons, with a range of implications for reef carbonate losses under warmer and more acidic oceans.

  3. Assessment of the value of microgravity to estimate the principal directions of the anisotropic transmissivity of aquifers from pumping tests: A study using a Hough transform based automatic algorithm

    NASA Astrophysics Data System (ADS)

    Fernández-Álvarez, José-Paulino; González-Quirós, Andrés; Rubio-Melendi, David

    2016-11-01

    Estimation of the hydraulic parameters of an aquifer is usually performed via interpretation of pumping tests. This invasive method requires drilling both pumping and observation wells. As the process is expensive, only a single pumping well and one or two observation wells or piezometers are generally drilled, at most. The interpretation is done assuming aquifer isotropy and homogeneity. However, in many aquifers, horizontal anisotropy in hydraulic conductivity greatly affects the flow regime. Its disregard may lead to important misinterpretations, especially for environmental impact assessments. This paper studies the capabilities of gravity for the identification and determination of the principal directions of anisotropy. This has been automatized using a methodology based on the Hough Transform. The results show how a microgravity survey could be an adequate and relatively cheap monitoring tool for the identification of anisotropy. This is valuable information that can be used in the decision making process for performing or discarding additional studies. Even more, the presented methodology can be extended to other studies in which contour maps are used to identify directionality in any process or property.

  4. An Interactive Exhibition about Animal Skeletons: Did the Visitors Learn Any Zoology?

    ERIC Educational Resources Information Center

    Tunnicliffe, Sue Dale; Laterveer-de Beer, Manon

    2002-01-01

    Explores museum visitors' understanding of skeleton exhibits and whether such exhibits increase their understanding of the zoology displayed. The exhibition under study focused on the diversity of vertebrae skeletons which were arranged according to the mode of locomotion. (DDR)

  5. Legal Problems of the Principal.

    ERIC Educational Resources Information Center

    Stern, Ralph D.; And Others

    The three talks included here treat aspects of the law--tort liability, student records, and the age of majority--as they relate to the principal. Specifically, the talk on torts deals with the consequences of principal negligence in the event of injuries to students. Assurance is given that a reasonable and prudent principal will have a minimum…

  6. The Principal as Resource Allocator.

    ERIC Educational Resources Information Center

    Peterson, Kent D.

    The effect of political influences on the allocation of personnel, money, facilities, and equipment by elementary school principals is discussed in this paper. The use of Zald's political economy framework as a tool for understanding the principal's role in allocating resources is described by the author. He suggests that the principal occupies a…

  7. Some Things Assistant Principals Do.

    ERIC Educational Resources Information Center

    Kealey, Robert J., Comp.

    The assistant principal of a Catholic elementary school carries out some of the duties (with the needed authority) of the school principal. How tasks and authority are delegated vary and depend upon the personality of each individual school. Fifteen assistant principals wrote essays relating one of their chief responsibilities to show a wide…

  8. The Principal Makes the Difference.

    ERIC Educational Resources Information Center

    Gretchko, Seymour; DeMont, Roger A.

    The role of the principal during the past two decades can be addressed by looking at the major developments of the era as they influenced the evolution of the principal's role. Fundamental changes in school structure were popularized during the expansionist period of the late 1950s and 1960s. Principals had to be agents of change. Then, a note of…

  9. The Future of Principal Evaluation

    ERIC Educational Resources Information Center

    Clifford, Matthew; Ross, Steven

    2012-01-01

    The need to improve the quality of principal evaluation systems is long overdue. Although states and districts generally require principal evaluations, research and experience tell that many state and district evaluations do not reflect current standards and practices for principals, and that evaluation is not systematically administered. When…

  10. Principals' Salaries, 2006-2007

    ERIC Educational Resources Information Center

    Cooke, Willa D.; Licciardi, Chris

    2007-01-01

    How do salaries of elementary and middle school principals compare with those of other administrators and classroom teachers? Are increases in salaries of principals keeping pace with increases in salaries of classroom teachers? And how have principals' salaries fared over the years when the cost of living is taken into account? This article…

  11. Principals' Salaries, 2005-2006

    ERIC Educational Resources Information Center

    Williams, Alicia R.

    2006-01-01

    How do salaries of elementary and middle school principals compare with those of other administrators and classroom teachers? Are increases in salaries of principals keeping pace with increases in salaries of classroom teachers? How have principals' salaries fared over the years when the cost of living is taken into account? To provide answers to…

  12. Principals Who Think Like Teachers

    ERIC Educational Resources Information Center

    Fahey, Kevin

    2013-01-01

    Being a principal is a complex job, requiring quick, on-the-job learning. But many principals already have deep experience in a role at the very essence of the principalship. They know how to teach. In interviews with principals, Fahey and his colleagues learned that thinking like a teacher was key to their work. Part of thinking the way a teacher…

  13. Interactions between Plasmodium falciparum skeleton-binding protein 1 and the membrane skeleton of malaria-infected red blood cells

    PubMed Central

    Buckingham, Donna W.; Blanc, Lionel; Hale, John; Guo, Xinhua; Pei, Xinhong; Herrmann, Susann; Hanssen, Eric G.; Coppel, Ross L.; Mohandas, Narla; An, Xiuli; Cooke, Brian M.

    2015-01-01

    During development inside red blood cells (RBCs), Plasmodium falciparum malaria parasites export proteins that associate with the RBC membrane skeleton. These interactions cause profound changes to the biophysical properties of RBCs that underpin the often severe and fatal clinical manifestations of falciparum malaria. P. falciparum erythrocyte membrane protein 1 (PfEMP1) is one such exported parasite protein that plays a major role in malaria pathogenesis since its exposure on the parasitised RBC surface mediates their adhesion to vascular endothelium and placental syncytioblasts. En route to the RBC membrane skeleton, PfEMP1 transiently associates with Maurer's clefts (MCs), parasite-derived membranous structures in the RBC cytoplasm. We have previously shown that a resident MC protein, skeleton-binding protein 1 (SBP1), is essential for the placement of PfEMP1 onto the RBC surface and hypothesised that the function of SBP1 may be to target MCs to the RBC membrane. Since this would require additional protein interactions, we set out to identify binding partners for SBP1. Using a combination of approaches, we have defined the region of SBP1 that binds specifically to defined subdomains of two major components of the RBC membrane skeleton, protein 4.1R and spectrin. We show that these interactions serve as one mechanism to anchor MCs to the RBC membrane skeleton, however, while they appear to be necessary, they are not sufficient for the translocation of PfEMP1 onto the RBC surface. The N-terminal domain of SBP1 that resides within the lumen of MCs clearly plays an essential, but presently unknown role in this process. PMID:25883090

  14. Interactions between Plasmodium falciparum skeleton-binding protein 1 and the membrane skeleton of malaria-infected red blood cells.

    PubMed

    Kats, Lev M; Proellocks, Nicholas I; Buckingham, Donna W; Blanc, Lionel; Hale, John; Guo, Xinhua; Pei, Xinhong; Herrmann, Susann; Hanssen, Eric G; Coppel, Ross L; Mohandas, Narla; An, Xiuli; Cooke, Brian M

    2015-07-01

    During development inside red blood cells (RBCs), Plasmodium falciparum malaria parasites export proteins that associate with the RBC membrane skeleton. These interactions cause profound changes to the biophysical properties of RBCs that underpin the often severe and fatal clinical manifestations of falciparum malaria. P. falciparum erythrocyte membrane protein 1 (PfEMP1) is one such exported parasite protein that plays a major role in malaria pathogenesis since its exposure on the parasitised RBC surface mediates their adhesion to vascular endothelium and placental syncytioblasts. En route to the RBC membrane skeleton, PfEMP1 transiently associates with Maurer's clefts (MCs), parasite-derived membranous structures in the RBC cytoplasm. We have previously shown that a resident MC protein, skeleton-binding protein 1 (SBP1), is essential for the placement of PfEMP1 onto the RBC surface and hypothesised that the function of SBP1 may be to target MCs to the RBC membrane. Since this would require additional protein interactions, we set out to identify binding partners for SBP1. Using a combination of approaches, we have defined the region of SBP1 that binds specifically to defined sub-domains of two major components of the RBC membrane skeleton, protein 4.1R and spectrin. We show that these interactions serve as one mechanism to anchor MCs to the RBC membrane skeleton, however, while they appear to be necessary, they are not sufficient for the translocation of PfEMP1 onto the RBC surface. The N-terminal domain of SBP1 that resides within the lumen of MCs clearly plays an essential, but presently unknown role in this process.

  15. Apatite mineralization in elasmobranch skeletons via a polyphosphate intermediate

    NASA Astrophysics Data System (ADS)

    Omelon, Sidney; Lacroix, Nicolas; Lildhar, Levannia; Variola, Fabio; Dean, Mason

    2014-05-01

    All vertebrate skeletons are stiffened with apatite, a calcium phosphate mineral. Control of apatite mineralization is essential to the growth and repair of the biology of these skeletons, ensuring that apatite is deposited in the correct tissue location at the desired time. The mechanism of this biochemical control remains debated, but must involve increasing the localized apatite saturation state. It was theorized in 1923 that alkaline phosphatase (ALP) activity provides this control mechanism by increasing the inorganic phosphate (Pi) concentration via dephosphorylation of phosphorylated molecules. The ALP substrate for biological apatite is not known. We propose that polyphosphates (polyPs) produced by mitochondria may be the substrate for biological apatite formation by ALP activity. PolyPs (PO3-)n, also known as condensed phosphates, represent a concentrated, bioavailable Pi-storage strategy. Mitochondria import Pi and synthesize phosphate polymers through an unknown biochemical mechanism. When chelated with calcium and/or other cations, the effective P-concentration of these neutrally charged, amorphous, polyP species can be very high (~ 0.5 M), without inducing phosphate mineral crystallization. This P-concentration in the low Pi-concentration biological environment offers a method of concentrating P well above an apatite supersaturation required for nucleation. Bone is the most studied mineralized skeletal tissue. However, locating and analyzing active mineralizing areas is challenging. We studied calcified cartilage skeletons of elasmobranch fishes (sharks, stingrays and relatives) to analyse the phosphate chemistry in this continually mineralizing skeleton. Although the majority of the elasmobranch skeleton is unmineralized cartilage, it is wrapped in an outer layer of mineralized tissue comprised of small tiles called tesserae. These calcified tesserae continually grow through the formation of new mineral on their borders. Co-localization of ALP and

  16. How Effective Is the Principal? Discrepancy between New Zealand Teachers' and Principals' Perceptions of Principal Effectiveness

    ERIC Educational Resources Information Center

    Sinnema, Claire E. L.; Robinson, Viviane M. J.; Ludlow, Larry; Pope, Denyse

    2015-01-01

    Multi-source evaluation of school principals is likely to become increasingly common in education contexts as the evidence accumulates about the relationship between principal effectiveness and student achievement. The purpose of this study was to examine (1) the magnitude and direction of discrepancy between how principals and their teachers…

  17. Real-Time Principal-Component Analysis

    NASA Technical Reports Server (NTRS)

    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.

  18. Principals' Perceptions Regarding Their Supervision and Evaluation

    ERIC Educational Resources Information Center

    Hvidston, David J.; Range, Bret G.; McKim, Courtney Ann

    2015-01-01

    This study examined the perceptions of principals concerning principal evaluation and supervisory feedback. Principals were asked two open-ended questions. Respondents included 82 principals in the Rocky Mountain region. The emerging themes were "Superintendent Performance," "Principal Evaluation Components," "Specific…

  19. Principal Component Analysis With Sparse Fused Loadings

    PubMed Central

    Guo, Jian; James, Gareth; Levina, Elizaveta; Michailidis, George; Zhu, Ji

    2014-01-01

    In this article, we propose a new method for principal component analysis (PCA), whose main objective is to capture natural “blocking” structures in the variables. Further, the method, beyond selecting different variables for different components, also encourages the loadings of highly correlated variables to have the same magnitude. These two features often help in interpreting the principal components. To achieve these goals, a fusion penalty is introduced and the resulting optimization problem solved by an alternating block optimization algorithm. The method is applied to a number of simulated and real datasets and it is shown that it achieves the stated objectives. The supplemental materials for this article are available online. PMID:25878487

  20. Cilia involvement in patterning and maintenance of the skeleton.

    PubMed

    Haycraft, Courtney J; Serra, Rosa

    2008-01-01

    Although the expression of cilia on chondrocytes was described over 40 years ago, the importance of this organelle in skeletal development and maintenance has only recently been recognized. Primary cilia are found on most mammalian cells and have been shown to play a role in chemosensation and mechanosensation. A growing number of human pleiotropic syndromes have been shown to be associated with ciliary or basal body dysfunction. Skeletal phenotypes, including alterations in limb patterning, endochondral bone formation, craniofacial development, and dentition, have been described in several of these syndromes. Additional insights into the potential roles and mechanisms of cilia action in the mammalian skeleton have been provided by research in model organisms including mouse and zebrafish. In this article we describe what is currently known about the localization of cilia in the skeleton as well as the roles and underlying molecular mechanisms of cilia in skeletal development. PMID:19147010

  1. An approach to the core skeleton of lancifodilactone F.

    PubMed

    Wang, Qiaoling; Chen, Chuo

    2008-03-20

    Two cycloaddition reactions were utilized for the construction of the 5,6,7-tricyclic skeleton of lancifodilactone F and buxapentalactone. A [2+2] ketene cycloaddition reaction was first used to set their adjacent all-carbon quaternary centers at the 5,6-ring junction. An arene-olefin meta-photocycloaddition reaction was then used to install the 6- and 7-membered rings concurrently.

  2. Spectrin-based skeleton as an actor in cell signaling.

    PubMed

    Machnicka, B; Grochowalska, R; Bogusławska, D M; Sikorski, A F; Lecomte, M C

    2012-01-01

    This review focuses on the recent advances in functions of spectrins in non-erythroid cells. We discuss new data concerning the commonly known role of the spectrin-based skeleton in control of membrane organization, stability and shape, and tethering protein mosaics to the cellular motors and to all major filament systems. Particular effort has been undertaken to highlight recent advances linking spectrin to cell signaling phenomena and its participation in signal transduction pathways in many cell types.

  3. How NASA KSC Controls Interfaces with the use of Motion Skeletons and Product Structure

    NASA Technical Reports Server (NTRS)

    Jones, Corey

    2013-01-01

    This presentation will show how NASA KSC controls interfaces for Modular Product Architecture (MPA) using Locator Skeletons, Interface Skeletons, and Product Structure, to be combined together within a Motion Skeleton. The user will learn how to utilize skeleton models to communicate interface data, as successfully done at NASA KSC in their use of Motion Skeletons to control interfaces for multi-launch systems. There will be discussion of the methodology used to control design requirements through WTParts, and how to utilize product structure for non-CAD documents.

  4. Limited Trabecular Bone Density Heterogeneity in the Human Skeleton

    PubMed Central

    Chirchir, Habiba

    2016-01-01

    There is evidence for variation in trabecular bone density and volume within an individual skeleton, albeit in a few anatomical sites, which is partly dependent on mechanical loading. However, little is known regarding the basic variation in trabecular bone density throughout the skeleton in healthy human adults. This is because research on bone density has been confined to a few skeletal elements, which can be readily measured using available imaging technology particularly in clinical settings. This study comprehensively investigates the distribution of trabecular bone density within the human skeleton in nine skeletal sites (femur, proximal and distal tibia, third metatarsal, humerus, ulna, radius, third metacarpal, and axis) in a sample of N = 20 individuals (11 males and 9 females). pQCT results showed that the proximal ulna (mean = 231.3 mg/cm3) and axis vertebra (mean = 234.3 mg/cm3) displayed significantly greater (p < 0.01) trabecular bone density than other elements, whereas there was no significant variation among the rest of the elements (p > 0.01). The homogeneity of the majority of elements suggests that these sites are potentially responsive to site-specific genetic factors. Secondly, the lack of correlation between elements (p > 0.05) suggests that density measurements of one anatomical region are not necessarily accurate measures of other anatomical regions. PMID:27148458

  5. Limited Trabecular Bone Density Heterogeneity in the Human Skeleton.

    PubMed

    Chirchir, Habiba

    2016-01-01

    There is evidence for variation in trabecular bone density and volume within an individual skeleton, albeit in a few anatomical sites, which is partly dependent on mechanical loading. However, little is known regarding the basic variation in trabecular bone density throughout the skeleton in healthy human adults. This is because research on bone density has been confined to a few skeletal elements, which can be readily measured using available imaging technology particularly in clinical settings. This study comprehensively investigates the distribution of trabecular bone density within the human skeleton in nine skeletal sites (femur, proximal and distal tibia, third metatarsal, humerus, ulna, radius, third metacarpal, and axis) in a sample of N = 20 individuals (11 males and 9 females). pQCT results showed that the proximal ulna (mean = 231.3 mg/cm(3)) and axis vertebra (mean = 234.3 mg/cm(3)) displayed significantly greater (p < 0.01) trabecular bone density than other elements, whereas there was no significant variation among the rest of the elements (p > 0.01). The homogeneity of the majority of elements suggests that these sites are potentially responsive to site-specific genetic factors. Secondly, the lack of correlation between elements (p > 0.05) suggests that density measurements of one anatomical region are not necessarily accurate measures of other anatomical regions.

  6. Data for the Reference Man: skeleton content of chemical elements.

    PubMed

    Zaichick, Vladimir

    2013-03-01

    This study was undertaken to provide reference values of chemical element mass fractions in intact bone of Reference (European Caucasian) Man/Woman. The rib bone samples investigated were obtained from autopsies of 84 apparently healthy 15-58-year-old citizens (38 females and 46 males) of a non-industrial region in the Central European part of Russia who had suffered sudden death. The mass fractions (mg/kg given on a wet mass basis) of 69 elements in these bone samples were measured by using neutron activation analysis with high-resolution spectrometry of short-lived and long-lived radionuclides, particle-induced gamma-ray emission, inductively coupled plasma atomic emission spectrometry, and inductively coupled plasma mass spectrometry including necessary quality control measures. Using published and measured data, mass fraction values of the 79 elements for the rib bone have been derived. Based on accepted rib to skeleton mass fractions and reference values of skeleton mass for Reference Man, the elemental burdens in the skeleton were estimated. These results may provide a representative bases for establishing related reference values for the Russian Reference Man/Woman and for revising and adding current reference values for the International Commission on Radiological Protection. The data presented will also be very valuable for many other applications in radiation protection, radiotherapy radiation dosimetry, and other scientific fields.

  7. Quantifying the osteocyte network in the human skeleton.

    PubMed

    Buenzli, Pascal R; Sims, Natalie A

    2015-06-01

    Osteocytes form an extensive cellular network throughout the hard tissue matrix of the skeleton, which is known to regulate skeletal structure. However due to limitations in imaging techniques, the magnitude and complexity of this network remain undefined. We have used data from recent papers obtained by new imaging techniques, in order to estimate absolute and relative quantities of the human osteocyte network and form a more complete understanding of the extent and nature of this network. We estimate that the total number of osteocytes within the average adult human skeleton is ~42 billion and that the total number of osteocyte dendritic projections from these cells is ~3.7 trillion. Based on prior measurements of canalicular density and a mathematical model of osteocyte dendritic process branching, we calculate that these cells form a total of 23 trillion connections with each other and with bone surface cells. We estimate the total length of all osteocytic processes connected end-to-end to be 175,000 km. Furthermore, we calculate that the total surface area of the lacuno-canalicular system is 215 m(2). However, the residing osteocytes leave only enough space for 24 mL of extracellular fluid. Calculations based on measurements in lactation-induced murine osteocytic osteolysis indicate a potential total loss of ~16,000 mm(3) (16 mL) of bone by this process in the human skeleton. Finally, based on the average speed of remodelling in the adult, we calculate that 9.1 million osteocytes are replenished throughout the skeleton on a daily basis, indicating the dynamic nature of the osteocyte network. We conclude that the osteocyte network is a highly complex communication network, and is much more vast than commonly appreciated. It is at the same order of magnitude as current estimates of the size of the neural network in the brain, even though the formation of the branched network differs between neurons and osteocytes. Furthermore, continual replenishment of large

  8. Status of Programs for Principals

    ERIC Educational Resources Information Center

    Nickerson, Neal C.

    1972-01-01

    Claiming that there's an aura of dissatisfaction with the present pre- and inservice programs for principals, the writer reports his findings about existing programs and suggested improvements. (Editor)

  9. The Principal and Fiscal Management. Elementary Principal Series No. 6.

    ERIC Educational Resources Information Center

    Walters, James K.; Marconnit, George D.

    The sixth of six volumes in the "Elementary Principal Series," this booklet is designed to help principals develop sound fiscal management strategies at the building level. The first section reviews Indiana statutory provisions for handling extracurricular and booster group funds. The second section presents guidelines for managing school funds.…

  10. From Training Great Principals to Preparing Principals for Practice

    ERIC Educational Resources Information Center

    Militello, Matthew; Rallis, Sharon

    2009-01-01

    We offer the collaborative inquiry-action cycle as a framework for principals' practice and principal preparation. The cycle is a pragmatic tool that does not prescribe behaviors or contexts. Moreover, the cycle does not represent another programmatic solution or model for leadership. Rather the power of the cycle is that it drives collaboration,…

  11. Censored-Data Correlation and Principal Component Dynamic Programming

    NASA Astrophysics Data System (ADS)

    Saad, Maarouf; Turgeon, Andre; Stedinger, Jery R.

    1992-08-01

    A principal component stochastic dynamic programming algorithm for stochastic multireservoir hydropower system operation optimization was proposed by Saad and Turgeon (1988). The dimension of the state space of the system is reduced by using only the major principal components of the system's state as determined by a principal component analysis of the results of a deterministic optimization. A significant refinement of the procedure is to employ censored-data principal component analysis. The more sophisticated statistical analysis provides a better model of the full dynamic range of the reservoir system's state, explains more observed variability of the reservoir volumes, and provides more accurate estimates of the statistical description's parameters. In an example presented of a four-reservoir system, the first component of the censored-data principal component analysis, for a given month, explained all but 7% of the uncensored system's variability, whereas the standard analysis for the same month left 12% of the observed system's variability unexplained.

  12. Skeleton-based region competition for automated gray matter and white matter segmentation of human brain MR images

    NASA Astrophysics Data System (ADS)

    Chu, Yong; Chen, Ya-Fang; Su, Min-Ying; Nalcioglu, Orhan

    2005-04-01

    Image segmentation is an essential process for quantitative analysis. Segmentation of brain tissues in magnetic resonance (MR) images is very important for understanding the structural-functional relationship for various pathological conditions, such as dementia vs. normal brain aging. Different brain regions are responsible for certain functions and may have specific implication for diagnosis. Segmentation may facilitate the analysis of different brain regions to aid in early diagnosis. Region competition has been recently proposed as an effective method for image segmentation by minimizing a generalized Bayes/MDL criterion. However, it is sensitive to initial conditions - the "seeds", therefore an optimal choice of "seeds" is necessary for accurate segmentation. In this paper, we present a new skeleton-based region competition algorithm for automated gray and white matter segmentation. Skeletons can be considered as good "seed regions" since they provide the morphological a priori information, thus guarantee a correct initial condition. Intensity gradient information is also added to the global energy function to achieve a precise boundary localization. This algorithm was applied to perform gray and white matter segmentation using simulated MRI images from a realistic digital brain phantom. Nine different brain regions were manually outlined for evaluation of the performance in these separate regions. The results were compared to the gold-standard measure to calculate the true positive and true negative percentages. In general, this method worked well with a 96% accuracy, although the performance varied in different regions. We conclude that the skeleton-based region competition is an effective method for gray and white matter segmentation.

  13. Time Management for New Principals

    ERIC Educational Resources Information Center

    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…

  14. School Principals' Sources of Knowledge

    ERIC Educational Resources Information Center

    Perkins, Arland Early

    2014-01-01

    The purpose of this study was to determine what sources of professional knowledge are available to principals in 1 rural East Tennessee school district. Qualitative research methods were applied to gain an understanding of what sources of knowledge are used by school principals in 1 rural East Tennessee school district and the barriers they face…

  15. What Do Effective Principals Do?

    ERIC Educational Resources Information Center

    Protheroe, Nancy

    2011-01-01

    Much has been written during the past decade about the changing role of the principal and the shift in emphasis from manager to instructional leader. Anyone in education, and especially principals themselves, could develop a mental list of responsibilities that fit within each of these realms. But research makes it clear that both those aspects of…

  16. Innovation Management Perceptions of Principals

    ERIC Educational Resources Information Center

    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…

  17. Great Principals at Scale: Toolkit

    ERIC Educational Resources Information Center

    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…

  18. Critical Issues Facing School Principals

    ERIC Educational Resources Information Center

    Styron, Ronald A., Jr.; Styron, Jennifer L.

    2011-01-01

    The purpose of this study was to further extend research initially conducted in 2003 pertaining to the critical issues K-12 principals address on a daily basis. The study involved surveying school principals within the state of Mississippi to discover the critical issues they identified, the significance level of these issues, and the rationale…

  19. Burnout among Elementary School Principals

    ERIC Educational Resources Information Center

    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…

  20. What Principals Think Motivates Teachers

    ERIC Educational Resources Information Center

    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…

  1. We Need Principals Who Understand.

    ERIC Educational Resources Information Center

    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)

  2. Principal Appraisals Get a Remake

    ERIC Educational Resources Information Center

    Zubrzycki, Jaclyn

    2013-01-01

    A growing number of school districts--including large ones like those in Chicago, Dallas, Los Angeles, and Hawaii--have become recent converts to new principal-evaluation systems that tie school leaders' appraisals to student test scores. As of this school year, student achievement accounts for 40 percent to 50 percent of principals' evaluations…

  3. The Effective and Reflective Principal

    ERIC Educational Resources Information Center

    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…

  4. Great New Resources for Principals

    ERIC Educational Resources Information Center

    Williamson, Ron

    2010-01-01

    The end of the school year is a hectic time for high school principals. Summer often provides a brief opportunity to "kick-back" and take time to rest, relax and spend some time thinking about the coming school year. As the school year ends the author would like to introduce several new or updated resources that every high school principal will…

  5. The Principal and the Community.

    ERIC Educational Resources Information Center

    Schumack, Kenneth A.

    The evolution of a run-down inner city elementary school into a flourishing community school is documented by its principal. By going out into the community and visiting in parents' homes, this principal built a base of support for innovations, such as individualized instruction and tutoring, as well as a lunch and breakfast program. Student…

  6. The Principal in Metropolitan Schools.

    ERIC Educational Resources Information Center

    Erickson, Donald A., Ed.; Reller, Theodore L., Ed.

    This collection of articles is designed to help metropolitan school principals meet the challenges of their positions. It is especially concerned with how principals can contribute to effective education for students of markedly heterogenous backgrounds. The authors deal with such issues as the principalship and metropolitan administration, the…

  7. Principals' Perceptions of Successful Leadership

    ERIC Educational Resources Information Center

    Childers, Gary L.

    2013-01-01

    The purposes of this qualitative multiple case study were to determine the catalysts and pathways that caused principals to move from managers to effective leaders. Data were collected through a series of interviews with 4 principals who were selected through a purposeful sampling procedure. The interviews were audio recorded, transcribed, and…

  8. Bureaucratic Control and Principal Role.

    ERIC Educational Resources Information Center

    Bezdek, Robert; And Others

    The purposes of this study were to determine the manner in which the imposition of increased bureaucratic control over principals influenced their allocation of time to tasks and to investigate principals' perceptions of the changes in their roles brought about by this increased control. The specific bureaucratic control system whose effects were…

  9. The Principal as Curriculum Leader

    ERIC Educational Resources Information Center

    Jenkins, Judy; Pfeifer, R. Scott

    2012-01-01

    Today's reform landscape transcends instructional leadership and data-based decision-making skills. This is not to say that those behaviors are not essential to a principal's success, but they no longer suffice. Principals do not need to be curriculum experts, but they do need to lead their schools with full knowledge of the Common Core State…

  10. Weightlessness and the human skeleton: A new perspective

    NASA Technical Reports Server (NTRS)

    Holick, Michael F.

    1994-01-01

    It is now clear after more than two decades of space exploration that one of the major short- and long-term effects of microgravity on the human body is the loss of bone. The purpose of this presentation will be to review the data regarding the impact of microgravity and bed rest on calcium and bone metabolism. The author takes the position in this Socratic debate that the effect of microgravity on bone metabolism can be either reversed or mitigated. As we begins to contemplate long-duration space flight and habitation of Space Station Freedom and the moon, one of the issues that needs to be addressed is whether humans need to maintain a skeleton that has been adapted for the one-g force on earth. Clearly, in the foreseeable future, a healthy and structurally sound skeleton will be required for astronauts to shuttle back and forth from earth to the moon, space station, and Mars. Based on most available data from bed-rest studies and the short- and long-duration microgravity experiences by astronauts and cosmonauts, bone loss is a fact of life in this environment. With the rapid advances in understanding of bone physiology it is now possible to contemplate measures that can prevent or mitigate microgravity-induced bone loss. Will the new therapeutic approaches for enhancing bone mineralization be useful for preventing significant bone loss during long-term space flight? Are there other approaches such as exercise and electrical stimulation that can be used to mitigate the impact of microgravity on the skeleton? A recent study that evaluated the effect of microgravity on bone modeling in developing chick embryos may perhaps provide a new perspective about the impact of microgravity on bone metabolism.

  11. Anabolic effects of IGF-1 signaling on the skeleton

    PubMed Central

    Tahimic, Candice G. T.; Wang, Yongmei; Bikle, Daniel D.

    2013-01-01

    This review focuses on the anabolic effects of IGF-1 signaling on the skeleton, emphasizing the requirement for IGF-1 signaling in normal bone formation and remodeling. We first discuss the genomic context, splicing variants, and species conservation of the IGF-1 locus. The modulation of IGF-1 action by growth hormone (GH) is then reviewed while also discussing the current model which takes into account the GH-independent actions of IGF-1. Next, the skeletal phenotypes of IGF-1-deficient animals are described in both embryonic and postnatal stages of development, which include severe dwarfism and an undermineralized skeleton. We then highlight two mechanisms by which IGF-1 exerts its anabolic action on the skeleton. Firstly, the role of IGF-1 signaling in the modulation of anabolic effects of parathyroid hormone (PTH) on bone will be discussed, presenting in vitro and in vivo studies that establish this concept and the proposed underlying molecular mechanisms involving Indian hedgehog (Ihh) and the ephrins. Secondly, the crosstalk of IGF-1 signaling with mechanosensing pathways will be discussed, beginning with the observation that animals subjected to skeletal unloading by hindlimb elevation are unable to mitigate cessation of bone growth despite infusion with IGF-1 and the failure of IGF-1 to activate its receptor in bone marrow stromal cell cultures from unloaded bone. Disrupted crosstalk between IGF-1 signaling and the integrin mechanotransduction pathways is discussed as one of the potential mechanisms for this IGF-1 resistance. Next, emerging paradigms on bone-muscle crosstalk are examined, focusing on the potential role of IGF-1 signaling in modulating such interactions. Finally, we present a future outlook on IGF research. PMID:23382729

  12. A skeleton model for the MJO with refined vertical structure

    NASA Astrophysics Data System (ADS)

    Thual, Sulian; Majda, Andrew J.

    2016-05-01

    The Madden-Julian oscillation (MJO) is the dominant mode of variability in the tropical atmosphere on intraseasonal timescales and planetary spatial scales. The skeleton model is a minimal dynamical model that recovers robustly the most fundamental MJO features of (I) a slow eastward speed of roughly 5 {ms}^{-1}, (II) a peculiar dispersion relation with dω /dk ≈ 0, and (III) a horizontal quadrupole vortex structure. This model depicts the MJO as a neutrally-stable atmospheric wave that involves a simple multiscale interaction between planetary dry dynamics, planetary lower-tropospheric moisture and the planetary envelope of synoptic-scale activity. Here we propose and analyse an extended version of the skeleton model with additional variables accounting for the refined vertical structure of the MJO in nature. The present model reproduces qualitatively the front-to-rear vertical structure of the MJO found in nature, with MJO events marked by a planetary envelope of convective activity transitioning from the congestus to the deep to the stratiform type, in addition to a front-to-rear structure of moisture, winds and temperature. Despite its increased complexity the present model retains several interesting features of the original skeleton model such as a conserved energy and similar linear solutions. We further analyze a model version with a simple stochastic parametrization for the unresolved details of synoptic-scale activity. The stochastic model solutions show intermittent initiation, propagation and shut down of MJO wave trains, as in previous studies, in addition to MJO events with a front-to-rear vertical structure of varying intensity and characteristics from one event to another.

  13. Shedding light into the function of the earliest vertebrate skeleton

    NASA Astrophysics Data System (ADS)

    Martinez-Perez, Carlos; Purnell, Mark; Rayfield, Emily; Donoghue, Philip

    2016-04-01

    Conodonts are an extinct group of jawless vertebrates, the first in our evolutionary lineage to develop a biomineralized skeleton. As such, the conodont skeleton is of great significance because of the insights it provides concerning the biology and function of the primitive vertebrate skeleton. Conodont function has been debated for a century and a half on the basis of its paleocological importance in the Palaezoic ecosystems. However, due to the lack of extanct close representatives and the small size of the conodont element (under a milimiter in length) strongly limited their functional analysis, traditional restricted to analogy. More recently, qualitative approaches have been developed, facilitating tests of element function based on occlusal performance and analysis of microwear and microstructure. In this work we extend these approaches using novel quantitative experimental methods including Synchrotron Radiation X-ray Tomographic Microscopy or Finite Element Analysis to test hypotheses of conodont function. The development of high resolution virtual models of conodont elements, together with biomechanical approaches using Finite Element analysis, informed by occlusal and microwear analyses, provided conclusive support to test hypothesis of structural adaptation within the crown tissue microstructure, showing a close topological co-variation patterns of compressive and tensile stress distribution with different crystallite orientation. In addition, our computational analyses strongly support a tooth-like function for many conodont species. Above all, our study establishes a framework (experimental approach) in which the functional ecology of conodonts can be read from their rich taxonomy and phylogeny, representing an important attempt to understand the role of this abundant and diverse clade in the Phanerozoic marine ecosystems.

  14. Coevolution of caudal skeleton and tail feathers in birds.

    PubMed

    Felice, Ryan N

    2014-12-01

    Birds are capable of a wide range of aerial locomotor behaviors in part because of the derived structure and function of the avian tail. The tail apparatus consists of a several mobile (free) caudal vertebrae, a terminal skeletal element (the pygostyle), and an articulated fan of tail feathers that may be spread or folded, as well as muscular and fibroadipose structures that facilitate tail movements. Morphological variation in both the tail fan and the caudal skeleton that supports it are well documented. The structure of the tail feathers and the pygostyle each evolve in response to functional demands of differing locomotor behaviors. Here, I test whether the integument and skeleton coevolve in this important locomotor module. I quantified feather and skeletal morphology in a diverse sample of waterbirds and shorebirds using a combination of linear and geometric morphometrics. Covariation between tail fan shape and skeletal morphology was then tested using phylogenetic comparative methods. Pygostyle shape is found to be a good predictor of tail fan shape (e.g., forked, graduated), supporting the hypothesis that the tail fan and the tail skeleton have coevolved. This statistical relationship is used to reconstruct feather morphology in an exemplar fossil waterbird, Limnofregata azygosternon. Based on pygostyle morphology, this taxon is likely to have exhibited a forked tail fan similar to that of its extant sister clade Fregata, despite differing in inferred ecology and other aspects of skeletal anatomy. These methods may be useful in reconstructing rectricial morphology in other extinct birds and thus assist in characterizing the evolution of flight control surfaces in birds.

  15. The potential origins and palaeoenvironmental implications of high temporal resolution δ 18O heterogeneity in coral skeletons

    NASA Astrophysics Data System (ADS)

    Allison, Nicola; Finch, Adrian A.; EIMF

    2010-10-01

    δ 18O was determined at high spatial resolution (beam diameter ˜30 μm) by secondary ion mass spectrometry (SIMS) across 1-2 year sections of 2 modern Porites lobata coral skeletons from Hawaii. We observe large (>2‰) cyclical δ 18O variations that typically cover skeletal distances equivalent to periods of ˜20-30 days. These variations do not reflect seawater temperature or composition and we conclude that skeletal δ 18O is principally controlled by other processes. Calcification site pH in one coral record was estimated from previous SIMS measurements of skeletal δ 11B. We model predicted skeletal δ 18O as a function of calcification site pH, DIC residence time at the site and DIC source (reflecting the inputs of seawater and molecular CO 2 to the site). We assume that oxygen isotopic equilibration proceeds at the rates observed in seawater and that only the aqueous carbonate ion is incorporated into the precipitating aragonite. We reproduce successfully the observed skeletal δ 18O range by assuming that DIC is rapidly utilised at the calcification site (within 1 h) and that ˜80% of the skeletal carbonate is derived from seawater. If carbonic anhydrase catalyses the reversible hydration of CO 2 at the calcification site, then oxygen isotopic equilibration times may be substantially reduced and a larger proportion of the skeletal carbonate could be derived from molecular CO 2. Seasonal skeletal δ 18O variations are most pronounced in the skeleton deposited from late autumn to winter (and coincide with the high density skeletal bands) and are dampened in skeleton deposited from spring to summer. We observed no annual pattern in sea surface temperature or photosynthetically active radiation variability which could potentially correlate with the coral δ 18O. At present we are unable to resolve an environmental cue to drive seasonal patterns of short term skeletal δ 18O heterogeneity.

  16. Effect of photosynthetic light dosage on carbon isotope composition in the coral skeleton: Long-term culture of Porites spp.

    NASA Astrophysics Data System (ADS)

    Omata, Tamano; Suzuki, Atsushi; Sato, Takanori; Minoshima, Kayo; Nomaru, Eriko; Murakami, Akio; Murayama, Shohei; Kawahata, Hodaka; Maruyama, Tadashi

    2008-06-01

    Whereas the oxygen isotope ratio of the coral skeleton is used for reconstruction of past information on seawater, the carbon isotope ratio is considered a proxy for physiological processes, principally photosynthesis and respiration. However, the fractionation of carbon isotopes in biogenic carbonate such as coral skeleton is still unclear. We conducted a long-term culture experiment of Porites spp. corals at different light dosages (light intensity, 100, 300, or 500 μmol m-2 s-1; daily light period, 10 or 12 h) at 25 ± 0.6°C to examine the contribution of photosynthetic activity to skeletal carbon isotope composition. Corals were grown in sand-filtered seawater and not fed; thus, they subsisted from photosynthesis of symbiotic algae. As the daily dose of photosynthetically active radiation increased, the rate of annual extension also increased. Mean isotope compositions shifted; the carbon isotope compositions (δ13C) became heavier and the oxygen isotope compositions (δ18O) became lighter at higher radiation dose. Skeletal δ18O decrease coincided with increasing skeletal growth rate, indicating the influence of so-called kinetic isotope effects. The observed δ13C increase should be subject to both kinetic and metabolic isotope effects, with the latter reflecting skeletal δ13C enrichment due to photosynthesis by symbiotic algae. Using a vector approach in the δ13C-δ18O plane, we discriminated between kinetic and metabolic isotope effects on δ13C. The calculated δ13C changes from metabolic isotope effects were light dose dependent. The δ13C fractionation curve related to metabolic isotope effects is very similar to the photosynthesis-irradiance curve, indicating the direct contribution of photosynthetic activity to metabolic isotope effects. In contrast, δ13C fractionation related to kinetic isotope effects gradually increased as the growth rate increased. Our experiment demonstrated that the kinetic and metabolic isotope effects in coral skeleton

  17. [Mechanisms of growth, development and disease of the craniofacial skeleton].

    PubMed

    Yamashiro, Takashi

    2016-01-01

    Craniofacial skeleton is derived from several pieces of bone, which hold the brain and house the sensory organ of vision, hearing, taste and smell. It also serves as an entrance of the digestive and respiratory tracts. Hence, craniofacial complex develops under sophisticated balance between the shape and the function. Disruption of such balance leads to various types of malformation and/or deformation of the face. This review focuses on the molecular aspects of growth and developments of the craniofacial structures and also on the genetic basis of congenital craniofacial malformations.

  18. The complete skull and skeleton of an early dinosaur.

    PubMed

    Sereno, P C; Novas, F E

    1992-11-13

    The unearthing of a complete skull and skeleton of the early dinosaur Herrerasaurus ischigualastensis sheds light on the early evolution of dinosaurs. Discovered in the Upper Triassic Ischigualasto Formation of Argentina, the fossils show that Herrerasaurus, a primitive theropod, was an agile, bipedal predator with a short forelimb specialized for grasping and raking. The fossils clarify anatomical features of the common ancestor of all dinosaurs. Herrerasaurus and younger dinosaurs from Upper Triassic beds in Argentina suggest that the dinosaurian radiation was well under way before dinosaurs dominated terrestrial vertebrate communities in taxonomic diversity and abundance.

  19. [Princess Anna Vasa--her fascinating life story and skeleton].

    PubMed

    During, Ebba

    2005-01-01

    The Princess Anna Vasa was born in Sweden in 1568 and spent her first 19 years there. She was the daughter of the Swedish king Johan III and his wife, the Polish Royal Princess Katarina Jagellonica. She was brought up as a Catholic but converted to be a Protestant already in 1583 and remained a fervent Protestant to the end of her life. She was an exceptionally intelligent and extensively educated woman. When her brother became king, Sigismund III of Poland, she accompanied him there. She exerted great influence on Sigismund who was brought up to be a Catholic. She was persistent in her religion, yet working for religious liberty. "The Swedish Princess" was also named "the Queen of Polish Botany". She was never married and she died 57 years old in 1625. For religious reasons her body had to wait 11 years for a funeral of royal standing. The funeral took place in 1636 in St Mary's Church in Torun, Poland. During restoration work at the church in April 1994, Anna Vasa's skeleton was removed from the tomb, and an antropological investigation in order to establish her identity was carried by Dr Andrzej Florkowski at the Dept of Anthrop, Nicholas Copernicus University of Torun. I was invited to Torun to examine her remains in May 1995. The skeleton was in a rather good state of preservation. However, her grave had been plundered at least twice. Her skeleton lacked the right forearm and hand, probably as the result of the pillage of her rings and bracelets. Some other bones and teeth were also missing. At our ocular examination the skeleton revealed a number of anatomical deformations and pathological changes. A conventional radiography and CT of Anna Vasa's skeletal remains was later carried out in 1995 by M. Grzegorzewski, Z. Boron and W. Lasek at the Dept of Radiology, Med. Acad. of Bydgoszcz, Polen. A DNA-analysis was carried out by Dr Anders Götherström at the Archaeol. Res. Lab., Stockholm Univ. An odontological and radiological study was performed by Dr Sigrid I

  20. Changes of the facial skeleton in cases of neurofibromatosis.

    PubMed

    Koblin, I; Reil, B

    1975-03-01

    In 12 patients with neurofibromatosis of the maxillofacial region distinct changes of the facial skeleton were found, which in localisation and extent largely conformed to the more or less wide soft tissue hyperplasias. In pronounced cases, a combined maxillo-zygomatico-temporo-mandibular hypoplasia was present radiographically. These skeletal changes hardly can be interpreted as pressure atrophy caused by the adjacent neurofibromatous tumours; more likely they are the result of complex developmental disorders. A more detailed explanation possibly will be obtained, when development and skeletal changes are controlled radiographically over a long period of time.

  1. Nonlinear traveling wave solution for the MJO skeleton model

    NASA Astrophysics Data System (ADS)

    Chen, S.; Stechmann, S. N.

    2014-12-01

    Recently, a minimal dynamical model is presented for capturing MJO's fundamental features. The model is a nonlinear oscillator model for the MJO skeleton and it involves interactions between convection, moisture and circulation. I will present the exact nonlinear traveling wave solutions for the model based on its energy conservation. The exact nonlinear solution provides for an explicit comparison of features between linear and nonlinear waves such as dispersion relations and traveling wave speeds. Moreover, the nonlinear solutions, compared with the linear ones, produce a narrow region of active convection and a wider region of suppressed convection. These predictions offer nonlinear MJO features that could potentially be targets of observational investigations.

  2. Skeleton and glucose metabolism: a bone-pancreas loop.

    PubMed

    Faienza, Maria Felicia; Luce, Vincenza; Ventura, Annamaria; Colaianni, Graziana; Colucci, Silvia; Cavallo, Luciano; Grano, Maria; Brunetti, Giacomina

    2015-01-01

    Bone has been considered a structure essential for mobility, calcium homeostasis, and hematopoietic function. Recent advances in bone biology have highlighted the importance of skeleton as an endocrine organ which regulates some metabolic pathways, in particular, insulin signaling and glucose tolerance. This review will point out the role of bone as an endocrine "gland" and, specifically, of bone-specific proteins, as the osteocalcin (Ocn), and proteins involved in bone remodeling, as osteoprotegerin, in the regulation of insulin function and glucose metabolism. PMID:25873957

  3. Surface and curve skeletonization of large 3D models on the GPU.

    PubMed

    Jalba, Andrei C; Kustra, Jacek; Telea, Alexandru C

    2013-06-01

    We present a GPU-based framework for extracting surface and curve skeletons of 3D shapes represented as large polygonal meshes. We use an efficient parallel search strategy to compute point-cloud skeletons and their distance and feature transforms (FTs) with user-defined precision. We regularize skeletons by a new GPU-based geodesic tracing technique which is orders of magnitude faster and more accurate than comparable techniques. We reconstruct the input surface from skeleton clouds using a fast and accurate image-based method. We also show how to reconstruct the skeletal manifold structure as a polygon mesh and the curve skeleton as a polyline. Compared to recent skeletonization methods, our approach offers two orders of magnitude speed-up, high-precision, and low-memory footprints. We demonstrate our framework on several complex 3D models.

  4. A study on the discrimination of human skeletons using X-ray fluorescence and chemometric tools in chemical anthropology.

    PubMed

    Gonzalez-Rodriguez, J; Fowler, G

    2013-09-10

    Forensic anthropological investigations are often restricted in their outcomes by the resources allocated to them, especially in terms of positively identifying the victims exhumed from commingled mass graves. Commingled mass graves can be defined as those graves that contain a number of disarticulated human remains from different individuals that have been mixed by either natural processes or human interventions. The research developed aimed to apply the technique of non-destructive XRF analysis to test whether there is substantial differentiation within the trace elemental composition and their ratios of individuals to separate them using chemometric analysis. The results of the different atomic spectroscopic analyses combined with the use of multivariate analysis on a set of 5 skeletons produced a series of plots using Principal Component Analysis that helped to separate them with a high percentage of accuracy when two, three or four skeletons needed to be separated. Also, two new elemental ratios, Zn/Fe related to metabolic activities and K/Fe related to blood flow into the bone, have been defined for their use in forensic anthropology for the first time to aid in the separation.

  5. A Salary Formula for Principals

    ERIC Educational Resources Information Center

    Gilbert, Michael B.

    1975-01-01

    When each administrative salary contract is negotiated individually, inequities creep in, many administrators feel. This article suggests a formula for determining principals' salaries based on education and experience, days of work, and responsibilities. (Editor)

  6. Profile of a Successful Principal.

    ERIC Educational Resources Information Center

    Johnson, Thais

    1985-01-01

    Dick Curland, principal of Valley View Elementary School in Portland, Connecticut, enhances his effectiveness by maintaining high visibility, communicating clearly and frequently with others, supporting his staff, and developing positive personal contact with individual students. (PGD)

  7. XANES mapping of organic sulfate in three scleractinian coral skeletons

    NASA Astrophysics Data System (ADS)

    Cuif, Jean-Pierre; Dauphin, Yannicke; Doucet, Jean; Salome, Murielle; Susini, Jean

    2003-01-01

    The presence and localization of organic sulfate within coral skeletons are studied by using X-ray absorption near edge structure spectroscopy (XANES) fluorescence. XANES spectra are recorded from four reference sulfur-bearing organic molecules: three amino acids (H-S-C bonds in cysteine; C-S-C bonds in methionine; one disulfide bond C-S-S-C bonds in cystine) and a sulfated sugar (C-SO 4 bonds in chondroitin sulfate). Spectral responses of three coral skeletons show that the sulfated form is extremely dominant in coral aragonite, and practically exclusive within both centres of calcification and the surrounding fibrous tissues of coral septa. Mapping of S-sulfate concentrations in centres and fibres gives us direct evidence of high concentration of organic sulfate in centres of calcification. Additionally, a banding pattern of S-sulfate is visible in fibrous part of the coral septa, evidencing a biochemical zonation that corresponds to the step-by-step growth of fibres.

  8. Scaling of the hydrostatic skeleton in the earthworm Lumbricus terrestris.

    PubMed

    Kurth, Jessica A; Kier, William M

    2014-06-01

    The structural and functional consequences of changes in size or scale have been well studied in animals with rigid skeletons, but relatively little is known about scale effects in animals with hydrostatic skeletons. We used glycol methacrylate histology and microscopy to examine the scaling of mechanically important morphological features of the earthworm Lumbricus terrestris over an ontogenetic size range from 0.03 to 12.89 g. We found that L. terrestris becomes disproportionately longer and thinner as it grows. This increase in the length to diameter ratio with size means that, when normalized for mass, adult worms gain ~117% mechanical advantage during radial expansion, compared with hatchling worms. We also found that the cross-sectional area of the longitudinal musculature scales as body mass to the ~0.6 power across segments, which is significantly lower than the 0.66 power predicted by isometry. The cross-sectional area of the circular musculature, however, scales as body mass to the ~0.8 power across segments, which is significantly higher than predicted by isometry. By modeling the interaction of muscle cross-sectional area and mechanical advantage, we calculate that the force output generated during both circular and longitudinal muscle contraction scales near isometry. We hypothesize that the allometric scaling of earthworms may reflect changes in soil properties and burrowing mechanics with size. PMID:24871920

  9. DNA and bone structure preservation in medieval human skeletons.

    PubMed

    Coulson-Thomas, Yvette M; Norton, Andrew L; Coulson-Thomas, Vivien J; Florencio-Silva, Rinaldo; Ali, Nadir; Elmrghni, Samir; Gil, Cristiane D; Sasso, Gisela R S; Dixon, Ronald A; Nader, Helena B

    2015-06-01

    Morphological and ultrastructural data from archaeological human bones are scarce, particularly data that have been correlated with information on the preservation of molecules such as DNA. Here we examine the bone structure of macroscopically well-preserved medieval human skeletons by transmission electron microscopy and immunohistochemistry, and the quantity and quality of DNA extracted from these skeletons. DNA technology has been increasingly used for analyzing physical evidence in archaeological forensics; however, the isolation of ancient DNA is difficult since it is highly degraded, extraction yields are low and the co-extraction of PCR inhibitors is a problem. We adapted and optimised a method that is frequently used for isolating DNA from modern samples, Chelex(®) 100 (Bio-Rad) extraction, for isolating DNA from archaeological human bones and teeth. The isolated DNA was analysed by real-time PCR using primers targeting the sex determining region on the Y chromosome (SRY) and STR typing using the AmpFlSTR(®) Identifiler PCR Amplification kit. Our results clearly show the preservation of bone matrix in medieval bones and the presence of intact osteocytes with well preserved encapsulated nuclei. In addition, we show how effective Chelex(®) 100 is for isolating ancient DNA from archaeological bones and teeth. This optimised method is suitable for STR typing using kits aimed specifically at degraded and difficult DNA templates since amplicons of up to 250bp were successfully amplified.

  10. Versatility of Distraction Osteogenesis for the Craniofacial Skeleton.

    PubMed

    Klement, Kristen A; Black, Jonathan S; Denny, Arlen D

    2016-05-01

    Malformations of the craniofacial skeleton are common. Restoration of anatomic shape, size, and position has been traditionally accomplished using autologous bone grafting to fill gaps created by surgery and segmental movement. The authors present their practice using distraction in many different ages and settings over 20 years. A retrospective review was performed of all craniofacial patients treated using distraction osteogenesis for mandible, midface, and calvarium. The authors identified 205 patient. Mandible: 112 patients were treated at an average age of 3.4 years. 18.8% of patients required repeat distraction. There was no difference in the neonatal versus older group (P = 0.71). There were significantly higher reoperation rates in syndromic children (P < 0.01). Midface: 58 patients underwent Lefort III distraction at an average age of 13.6 years. One (1.7%) required repeat distraction (Miller syndrome). Five (8.6%) patients underwent subsequent Lefort I advancement for occlusal changes. Calvarium: 33 patients were treated at an average age of 4.7 years. No repeat distractions were performed. One patient required an additional advancement procedure. Distraction demonstrates successful long-term correction of defects in the craniofacial skeleton with the versatility and control needed to treat the wide spectrum of deformity.

  11. The origin of conodonts and of vertebrate mineralized skeletons

    USGS Publications Warehouse

    Murdock, Duncan J.E.; Dong, Xi-Ping; Repetski, John E.; Marone, Federica; Stampanoni, Marco; Donoghue, Philip C.J.

    2013-01-01

    Conodonts are an extinct group of jawless vertebrates whose tooth-like elements are the earliest instance of a mineralized skeleton in the vertebrate lineage, inspiring the ‘inside-out’ hypothesis that teeth evolved independently of the vertebrate dermal skeleton and before the origin of jaws. However, these propositions have been based on evidence from derived euconodonts. Here we test hypotheses of a paraconodont ancestry of euconodonts using synchrotron radiation X-ray tomographic microscopy to characterize and compare the microstructure of morphologically similar euconodont and paraconodont elements. Paraconodonts exhibit a range of grades of structural differentiation, including tissues and a pattern of growth common to euconodont basal bodies. The different grades of structural differentiation exhibited by paraconodonts demonstrate the stepwise acquisition of euconodont characters, resolving debate over the relationship between these two groups. By implication, the putative homology of euconodont crown tissue and vertebrate enamel must be rejected as these tissues have evolved independently and convergently. Thus, the precise ontogenetic, structural and topological similarities between conodont elements and vertebrate odontodes appear to be a remarkable instance of convergence. The last common ancestor of conodonts and jawed vertebrates probably lacked mineralized skeletal tissues. The hypothesis that teeth evolved before jaws and the inside-out hypothesis of dental evolution must be rejected; teeth seem to have evolved through the extension of odontogenic competence from the external dermis to internal epithelium soon after the origin of jaws.

  12. The skeleton as an intracrine organ for vitamin D metabolism.

    PubMed

    Anderson, Paul H; Atkins, Gerald J

    2008-12-01

    The endocrine hormone, 1alpha,25-dihydroxyvitamin D(3) (1,25D) is an important regulator of calcium and phosphorus homeostasis. In this context, 1,25D is generally recognized as necessary for the maintenance of a healthy skeleton through its actions on the small intestine. In this review, we highlight the direct effects of 1,25D on the constituent cells of the bone, actions that are independent of effects on the intestine and kidney. We also consider the evidence that 25D levels, not 1,25D levels, correlate best with parameters of bone health, and that the bone itself is a site of metabolic conversion of 25D into 1,25D, by virtue of its expression of the 25-hydroxyvitamin D 1alpha-hydroxylase, CYP27B1. We review the evidence that at least osteoblasts and chondrocytes, and possibly also bone resorbing osteoclasts, are capable of such metabolic conversion, and therefore that these cells likely participate in autocrine and paracrine loops of vitamin D metabolism. We conclude that the skeleton is an intracrine organ for vitamin D metabolism, challenging the long-held notion that 1,25D is solely an endocrine hormone.

  13. [Study of skeleton gravitation physiology and problem of osteoporosis].

    PubMed

    Oganov, V S

    2003-03-01

    Main osteoporosis definitions and some results of bone tissue research in Russian astronauts, patients, and healthy subjects, using modern osteodensitometry, are presented. Bone mineral density (BMD) was regularly decreased at lower segments of skeleton. In the skull bone and some other sites of upper part of skeleton, a tendency was revealed for an increase of the bone mineral content (BMC). The mean value of bone loss was within the normal range and not correlated with duration of space flight; it revealed a high individual variability and in some cases was clinically qualified as local osteopenia. On the ground of analysis of own results and animal and bone cultural experiments data in microgravity conditions, the described changes seem to be reflecting a deceleration of bone formation as an adaptive response of bone tissue to the mechanical unloading. The response is realized mainly on the tissue level. It does not exclude bone resorption activity as a result of changes in hierarchy of water and electrolytes metabolism as reflected by body fluid redistribution in cranial direction. The results obtained broaden our notions on pathogenesis of some types of osteoporosis in clinic.

  14. Reduction of absorbed doses in radiography of the facial skeleton

    SciTech Connect

    Julin, P.; Kraepelien, T.

    1984-11-01

    Radiation absorbed doses from radiography of the paranasal sinuses and the facial skeleton were measured with thermoluminescent dosimeters (TLD) on a phantom head using high-sensitivity screens in an Orbix stand. The entrance doses to the skin of the head ranged from 0.31 to 2.9 mGy per exposure. The absorbed dose from a full series of sinus exposures averaged 0.33 mGy for the oral mucous membrane, 0.33 mGy for the maxillary sinus mucous membrane, 0.11 mGy for the parotid gland, 0.15 mGy for the submandibular gland, 0.61 mGy for the eye lens, and 0.75 mGy for the thyroid gland region. A leaded soft collar adapted to the thyroid region reduced the thyroid doses by more than one order of magnitude, but also reduced the image field. The mean energy imparted from a full series of paranasal sinus projections was 4.8 mJ and from a total series of the facial skeleton, 7.9 mJ.

  15. The fine structure of the developing pelvic fin dermal skeleton in the trout Salmo gairdneri.

    PubMed

    Géraudie, J; Landis, W J

    1982-02-01

    The morphogenetic and ultrastructural features of the dermal skeleton in the pelvic fin bud of a teleost, the rainbow trout Salmo gairdneri, have been examined by light and electron microscopy. The principal structural components observed are lepidotrichia and actinotrichia. Lepidotrichia consist of two parallel and symmetrical bony demirays that form jointed segments within the fin. The demirays calcify in a proximodistal direction within the extracellular collagen network of the basal lamella belonging to the epidermal-dermal interface of the fin. Needle- and plate-like particles of a solid mineral phase appear to be associated with the collagen fibrils and with a fine, granular, interfibrillar material central to the demirays. Cellular processes and membrane-bound vesicles are absent from the regions of calcification. During fin growth, the bony, acellular lepidotrichia are separated from the epidermal-dermal interface by infiltrating mesenchymal cells in proximal fin regions; in distal areas, the lepidotrichia remain within the basal lamella. The actinotrichia are extensive unmineralized rods of elastoidin that occupy the distal margin of the fin and precede the differentiation of lepidotrichia. Once the lepidotrichia form, actinotrichia lie preferentially between their demirays. In some instances, structural interactions are suggested between actinotrichia and lepidotrichia. Considerations of embryologic and structural features of fin components fail to support the hypothesis that individual segments of lepidotrichia are modified scales in all fish. PMID:7072614

  16. Articulins and epiplasmins: two distinct classes of cytoskeletal proteins of the membrane skeleton in protists.

    PubMed

    Huttenlauch, I; Peck, R K; Stick, R

    1998-11-01

    The cortex of ciliates, dinoflagellates and euglenoids comprises a unique structure called the epiplasm, implicated in pattern-forming processes of the cell cortex and in maintaining cell shape. Despite significant variation in the structural organization of their epiplasm and cortex, a novel type of cytoskeletal protein named articulin is the principal constituent of the epiplasm in the euglenoid Euglena and the ciliate Pseudomicrothorax. For another ciliate, Paramecium, epiplasmins, a group of polypeptides with common biochemical properties, are the major constituents of the epiplasm. Using molecular tools and affinity purification we have selected polyclonal antibodies and identified epitopes of monoclonal antibodies that identify epitopes characteristic of articulins and epiplasmins. With these antibodies we have analysed the occurrence of the two types of cytoskeletal proteins in a dinoflagellate, a euglenoid and several ciliates. Our results indicate that both articulins and epiplasmins are present in these organisms, suggesting that both contribute to the organization of the membrane skeleton in protists. Articulins and epiplasmins represent two distinct classes of cytoskeletal proteins, since different polypeptides were labeled by articulin core domain-specific or epiplasmin epitope-specific antibodies in each organism studied. In one case, a polypeptide in Pseudomicrothorax was identified that reacts with both articulin core domain-specific and with anti-epiplasmin monoclonal antibodies; however, the epiplasmin monoclonal antibody epitope was mapped to the C terminus of the polypeptide, well outside the central VPV-repeat core domain that contains the articulin monoclonal antibody epitope and that is the hallmark of the articulins.

  17. Skeleton used for anatomical study brought for medico-legal autopsy: a case report.

    PubMed

    Bhardwaj, D N; Millo, T; Lalwani, S

    2007-01-01

    Knowledge of human anatomy is essential for all those practising medicine. The human skeleton is invariably used to study the anatomy of body structures. For this, many human skeletons are obtained from the market by students and teachers and are kept at home or in hostel rooms. However, after use the skeleton has to be disposed off properly. In the present case, a human skeleton used for study purposes was thrown away in garbage and someone informed the police about presence of skeletal remains in the garbage. The case was registered by the police and the skeletal remains were brought for medico-legal autopsy.

  18. [Disturbances of growth and development of the maxillofacial skeleton].

    PubMed

    Becking, A G; Hoppenreijs, Th J M; Tuinzing, D B

    2007-01-01

    Due to many developments in oral and maxillofacial surgery, the contribution of oral and maxillofacial surgeons in the diagnostics and treatment of growth and development disorders of the craniomandibulo-maxillofacial skeleton has become more and more important. Many disorders are treated by multidisciplinary teams including orthodontists and prosthodontists. Arbitrarily, 3 categories of growth and developmental disorders can be distinguished: dento-alveolar, dento-maxillofacial, and dento-maxillo-craniofacial disorders. In addition to classic bony reconstruction methods, new methodologies have been developed, such as distraction osteogenesis and simultaneous skin and soft tissue corrections. For many decades, the treatment of growth and development disorders has been a frequent subject of doctoral dissertations in The Netherlands. Attention is currently being paid to developing methods for three-dimensional planning and correction of these disorders, and methods which are minimally invasive.

  19. Mineral-bound noncollagenous proteins in archaeological human skeletons.

    PubMed

    Freundorfer, S; Grupe, G; Weickmann, D

    1995-05-01

    Archaeometric approaches to archaelogical human bone also include the extraction, identification and molecular analysis of surviving bone proteins. Due to its abundance as a matrix protein, most studies focus on collagen (e.g. radiocarbon dating). Also, a variety of serum proteins are detectable in excavated skeletons. Very limited knowledge still exists on mineral-bound noncollagenous bone proteins from ancient bones because, in the mature tissue, they occur in trace amounts only. Moreover, post-mortem decomposition is likely to change characteristic features of the molecules. Due to their suggested role as growth and developmental factors, identification and quantification of such proteins should be valuable for both physical anthropology and epidemiology. We present a valid method for the detection of small amounts of surviving mineral-bound noncollagenous proteins in excavated human bones up to 7500 years of age.

  20. Genetic Disorders of the Skeleton: A Developmental Approach

    PubMed Central

    Kornak, Uwe; Mundlos, Stefan

    2003-01-01

    Although disorders of the skeleton are individually rare, they are of clinical relevance because of their overall frequency. Many attempts have been made in the past to identify disease groups in order to facilitate diagnosis and to draw conclusions about possible underlying pathomechanisms. Traditionally, skeletal disorders have been subdivided into dysostoses, defined as malformations of individual bones or groups of bones, and osteochondrodysplasias, defined as developmental disorders of chondro-osseous tissue. In light of the recent advances in molecular genetics, however, many phenotypically similar skeletal diseases comprising the classical categories turned out not to be based on defects in common genes or physiological pathways. In this article, we present a classification based on a combination of molecular pathology and embryology, taking into account the importance of development for the understanding of bone diseases. PMID:12900795

  1. Simultaneous drag and flow measurements of Olympic skeleton athletes

    NASA Astrophysics Data System (ADS)

    Moon, Yae Eun; Digiulio, David; Peters, Steve; Wei, Timothy

    2009-11-01

    The Olympic sport of skeleton involves an athlete riding a small sled face first down a bobsled track at speeds up to 130 km/hr. In these races, the difference between gold and missing the medal stand altogether can be hundredths of a second per run. As such, reducing aerodynamic drag through proper body positioning is of first order importance. To better study the flow behavior and to improve the performance of the athletes, we constructed a static force balance system on a mock section of a bobsled track. Athlete and the sled are placed on the force balance system which is positioned at the exit of an open loop wind tunnel. Simultaneous drag force and DPIV velocity field measurements were made along with video recordings of body position to aid the athletes in determining their optimal aerodynamic body position.

  2. The oldest known primate skeleton and early haplorhine evolution.

    PubMed

    Ni, Xijun; Gebo, Daniel L; Dagosto, Marian; Meng, Jin; Tafforeau, Paul; Flynn, John J; Beard, K Christopher

    2013-06-01

    Reconstructing the earliest phases of primate evolution has been impeded by gaps in the fossil record, so that disagreements persist regarding the palaeobiology and phylogenetic relationships of the earliest primates. Here we report the discovery of a nearly complete and partly articulated skeleton of a primitive haplorhine primate from the early Eocene of China, about 55 million years ago, the oldest fossil primate of this quality ever recovered. Coupled with detailed morphological examination using propagation phase contrast X-ray synchrotron microtomography, our phylogenetic analysis based on total available evidence indicates that this fossil is the most basal known member of the tarsiiform clade. In addition to providing further support for an early dichotomy between the strepsirrhine and haplorhine clades, this new primate further constrains the age of divergence between tarsiiforms and anthropoids. It also strengthens the hypothesis that the earliest primates were probably diurnal, arboreal and primarily insectivorous mammals the size of modern pygmy mouse lemurs.

  3. Classification of pelvic ring fractures in skeletonized human remains.

    PubMed

    Báez-Molgado, Socorro; Bartelink, Eric J; Jellema, Lyman M; Spurlock, Linda; Sholts, Sabrina B

    2015-01-01

    Pelvic ring fractures are associated with high rates of mortality and thus can provide key information about circumstances surrounding death. These injuries can be particularly informative in skeletonized remains, yet difficult to diagnose and interpret. This study adapted a clinical system of classifying pelvic ring fractures according to their resultant degree of pelvic stability for application to gross human skeletal remains. The modified Tile criteria were applied to the skeletal remains of 22 individuals from the Cleveland Museum of Natural History and Universidad Nacional Autónoma de México that displayed evidence of pelvic injury. Because these categories are tied directly to clinical assessments concerning the severity and treatment of injuries, this approach can aid in the identification of manner and cause of death, as well as interpretations of possible mechanisms of injury, such as those typical in car-to-pedestrian and motor vehicle accidents. PMID:25381919

  4. Trace elements and the European skeleton through 5000 years.

    PubMed

    Smrčka, V; Jambor, J

    2000-01-01

    For our research, one thousand forty-four samples were taken from the femurs of 522 skeletons from 25 sites in Europe from the Neolithic Age (4000-5000 B.C), from La Téne Period, the Roman Era (500 B.C-400 A.D.), the Middle Ages and from contemporary cadavers. We found the following distribution of elements in the longitudional axis of long bones (the femurs and the tibias). The elements Zn, Fe, Ni, Cr, Pb, Mn, Co and Sn cumulated in the epiphysis. On the other hand, we found that Ca, Sr, Na and K prevailed in the central part of the diaphysis. In the central parts of the cross-section the highest concentration of the metal element Pb was in the external layer from the historical femurs. It was the same with cadavers of the recent population. A specific shift from Neolithic farming to agricultural intensification in the Roman Era was also apparent in the skeletons. Special sources of the above mentioned elements were found both in Celtic and Germanic tribes. Meat is the main source of zinc. Zinc is also important for the growth of the skeleton. When we investigated the development of the human skeleton during the last 5000 years we found the highest concetrations of Zn in communities with a good supply of animal food, whereas the lowest concentrations were paralleled with well-developed agriculturists. We assume the Neolithic gracilization, which is in the background for the increase of agricultural populations, is directly linked with the concentration of Zn and other elements essential for growth (Cu, Fe and others). The individuals most vulnerable to zinc deficiency include infants, adolescents during rapid growth phases and women during pregnancy and lactation. Trace elements in the bones of the La Téne period designate two areas of Celtic diet patterns--a "French one" (Roulier, Mont Trote and Acy Romance) and a "Czech one" (Karlov, Radovesice and Jenisův Ujezd). At Czech sites levels of zinc increased westward towards the Germanic region. Over the Germanic

  5. Companions for ``Nessie'' in the Milky Way's Skeleton

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-12-01

    The recent discovery of a purported bone of the Milky Way, a dark cloud nicknamed Nessie, has provided us with new clues for mapping out the spiral structure of our galaxy. It turns out that Nessie may not be alone: a follow-up study has identified more bones, potentially making up a skeleton of the Milky Way that traces out the densest parts of its spiral arms.Inconvenient Vantage PointHow many spiral arms does the Milky Way have? Where are they located? What does the structure look like between the arms? It may seem surprising that these fundamental questions dont yet have clear answers. But because were stuck in the galaxys disk, were forced to piece together our understanding of the Milky Ways structure based primarily on measurements of position and radial velocity of structures within the galactic plane.The discovery of Nessie presents an intriguing new tool to identify the layout of the galaxy. Nessie is a very long, thin, infrared-dark filament that runs along the modeled position of the Scutum-Centaurus arm and is believed therefore to trace the structure of the arm. In a new study led by Catherine Zucker (University of Virginia, Harvard-Smithsonian Center for Astrophysics), the authors have searched for additional bones like Nessie, hoping to use them to map out the skeleton of the Milky Way.New Bones DiscoveredIn this map of radial velocity vs. galactic longitude, the bone candidates are indicated by the numbered points. The colored lines indicate the positions of two of the galactic spiral arms, according to various models. Click for a closer look! [Zucker et al. 2015]Zucker and collaborators began by using World Wide Telescope, a tool that facilitates visualization of multiple layers of data at a variety of scales, to search through Spitzer infrared data for additional structures like Nessie. Searching specifically along the predicted positions of galactic arms, they found 15 initial bone candidates.Next, the team obtained radial-velocity data for the

  6. Reduction of absorbed doses in radiography of the facial skeleton

    SciTech Connect

    Julin, P.; Kraepelien, T.

    1984-11-01

    Radiation absorbed doses from radiography of the paranasal sinuses and the facial skeleton were measured with thermoluminescent dosimeters (TLD) on a phantom head using high-sensitivity screens in an Orbix stand. The entrance doses to the skin of the head ranged from 0.31 to 2.9 mGy per exposure. The absorbed dose from a full series of sinus exposures averaged 0.33 mGy for the oral mucous membrane, 0.33 mGy for the maxillary sinus mucous membrane, 0.11 MgY for the parotid gland, 0.15 MgY for the submandibular gland, 0.61 mGy for the eye lens, and 0.75 mGy for the thyroid gland region. A leaded soft collar adapted to the thyroid region reduced the thyroid doses by more than one order of magnitude, but also reduced the image field.

  7. Associated skeletons of a new middle Triassic "Rauisuchia" from Brazil.

    PubMed

    França, Marco Aurélio G; Ferigolo, Jorge; Langer, Max C

    2011-05-01

    For more than 30 million years, in early Mesozoic Pangea, "rauisuchian" archosaurs were the apex predators in most terrestrial ecosystems, but their biology and evolutionary history remain poorly understood. We describe a new "rauisuchian" based on ten individuals found in a single locality from the Middle Triassic (Ladinian) Santa Maria Formation of southern Brazil. Nine articulated and associated skeletons were discovered, three of which have nearly complete skulls. Along with sedimentological and taphonomic data, this suggests that those highly successful predators exhibited some kind of intraspecific interaction. Other monotaxic assemblages of Triassic archosaurs are Late Triassic (Norian-Rhaetian) in age, approximately 10 million years younger than the material described here. Indeed, the studied assemblage may represent the earliest evidence of gregariousness among archosaurs, adding to our knowledge on the origin of a behavior pattern typical of extant taxa.

  8. R-spondins: novel matricellular regulators of the skeleton.

    PubMed

    Knight, M Noelle; Hankenson, Kurt D

    2014-07-01

    R-spondins are a family of four matricellular proteins produced by a variety of cell-types. Structurally, R-spondins contain a TSR1 domain that retains the tryptophan structure and a modified cysteine-rich CSVCTG region. In addition, the R-spondins contain two furin repeats implicated in canonical Wnt signaling. R-spondins positively regulate canonical Wnt signaling by reducing Wnt receptor turnover and thereby increasing beta-catenin stabilization. R-spondins are prominently expressed in the developing skeleton and contribute to limb formation, particularly of the distal digit. Additionally, results suggest that R-spondins may contribute to the maintenance of adult bone mass by regulating osteoblastogenesis and bone formation.

  9. "Successful" Principals: A Contested Notion for Superintendents and Principals

    ERIC Educational Resources Information Center

    Scribner, Samantha M. Paredes; Crow, Gary M.; Lopez, Gerardo R.; Murtadha, Khaula

    2011-01-01

    The notion of "success" is narrowly defined and appropriated within an educational context. Typically limited to objective measures of organizational productivity, effectiveness, and efficiency, "successful" principal practices, we argue, engender action and attention to a broader array of issues and interrelationships. In this study, we conducted…

  10. Conceptualizing a System for Principal Evaluation

    ERIC Educational Resources Information Center

    Derrington, Mary Lynne; Sanders, Kellie

    2011-01-01

    A disconnect exists between principal leadership expectations and the actual practice of supervision and evaluation of principals. Increased principal responsibilities and rigorous standards require that a new approach to principal evaluation be considered. The authors provide a framework for a multi-dimensional approach to principal supervision…

  11. The proteome of the insoluble Schistosoma mansoni eggshell skeleton.

    PubMed

    Dewalick, Saskia; Bexkens, Michiel L; van Balkom, Bas W M; Wu, Ya-Ping; Smit, Cornelis H; Hokke, Cornelis H; de Groot, Philip G; Heck, Albert J R; Tielens, Aloysius G M; van Hellemond, Jaap J

    2011-04-01

    In schistosomiasis, the majority of symptoms of the disease is caused by the eggs that are trapped in the liver. These eggs elicit an immune reaction that leads to the formation of granulomas. The eggshell, which is a rigid insoluble structure built from cross-linked proteins, is the site of direct interaction between the egg and the immune system. However, the exact protein composition of the insoluble eggshell was previously unknown. To identify the proteins of the eggshell of Schistosoma mansoni we performed LC-MS/MS analysis, immunostaining and amino acid analysis on eggshell fragments. For this, eggshell protein skeleton was prepared by thoroughly cleaning eggshells in a four-step stripping procedure of increasing strength including urea and SDS to remove all material that is not covalently linked to the eggshell itself, but is part of the inside of the egg, such as Reynold's layer, von Lichtenberg's envelope and the miracidium. We identified 45 proteins of which the majority are non-structural proteins and non-specific for eggs, but are house-keeping proteins that are present in large quantities in worms and miracidia. Some of these proteins are known to be immunogenic, such as HSP70, GST and enolase. In addition, a number of schistosome-specific proteins with unknown function and no homology to any known annotated protein were found to be incorporated in the eggshell. Schistosome-specific glycoconjugates were also shown to be present on the eggshell protein skeleton. This study also confirmed that the putative eggshell protein p14 contributes largely to the eggshell. Together, these results give new insights into eggshell composition as well as eggshell formation. Those proteins that are present at the site and time of eggshell formation are incorporated in the cross-linked eggshell and this cross-linking does no longer occur when the miracidium starts secreting proteins. PMID:21236260

  12. Historic timber skeleton structures and the local seismic culture

    NASA Astrophysics Data System (ADS)

    Bostenaru, M.

    2009-04-01

    This presentation deals with the employment of timber skeleton structure and the local seismic culture. After the 1755 earthquake in the reconstruction of Lisbon a type of building with timber skeleton and masonry infill called "gaiola pombalina" was promoted, since this was designed to better resists earthquakes. "Gaiola" means cage, and it was also named after the Marques de Pombal who introduced it in the reconstruction following the earthquake. The „gaiola pombalina" presents a timber skeleton with Saint Andrew crosses in the interior walls with masonry infill and thick masonry load bearing walls loosing in thickness to the upper floors in the exterior walls. The masonry can fall out during earthquakes but the building remains staying given the interior timber skeleton. The type of buildings with timber structure and (masonry) infill behaved well in earthquakes in various parts of the earth, like Nepal (the dhaji dewary type), Pakistan, Turkey (the himiş type after the 1999 earthquake) [both latter types were researched by Langenbach, www.conservationtech.com and www.traditional-is-modern.net] and also in Germany after the 1356 earthquake (the Southern German subtype of Fachwerk). Also in Italy a subtype called "casa baraccata" was promoted in a construction code to a similar time (following the 1783 earthquake in Southern Italy, see Tobriner 1983) as that of the "gaiola pombalina", the time of the Baroque, when town planning acquired another status. Unlike at the "gaiola pombalina" the "casa baraccata" the timber skeleton is at the exterior walls. For this reason this type of buildings is considered to be an expression of the local seismic culture. However, this type of buildings is common also for areas where seismic risk is not an issue, like half-timbered in England and the northern subtype of Fachwerk in Northern Germany, and in some high seismic risk regions with mountains and timber resources like Romania is not spread. Given these premises the author

  13. Growth of Bi 2S 3 skeleton crystals with three-dimensional network morphologies

    NASA Astrophysics Data System (ADS)

    Wang, Debao; Shao, Mingwang; Yu, Dabin; Yu, Weichao; Qian, Yitai

    2003-07-01

    Skeleton crystals of Bi 2S 3 have been prepared via a solvothermal route using BiCl 3 and anhydrous sodium sulfite as starting reagents. Transmission electron microscopy studies showed that the rod-based skeleton crystals have three-dimensional network morphologies. The influence of reaction time and the temperatures has been discussed. A possible growth mechanism was proposed.

  14. Application of Skeleton Method in Interconnection of Cae Programs Used in Vehicle Design

    NASA Astrophysics Data System (ADS)

    Bucha, Jozef; Gavačová, Jana; Milesich, Tomáš

    2014-12-01

    This paper deals with the application of the skeleton method as the main element of interconnection of CAE programs involved in the process of vehicle design. This article focuses on the utilization of the skeleton method for mutual connection of CATIA V5 and ADAMS/CAR. Both programs can be used simultaneously during various stages of vehicle design.

  15. Biology Notes: How the Skeleton Functions in the Movement of Animals

    ERIC Educational Resources Information Center

    Worsley, C. J.

    1972-01-01

    Argues that the term skeleton is not a word denoting a structure but a word denoting a function--that of allowing animals the freedom of self-motivated purposive local motion. Indeed a skeleton is a necessary prerequisite for there to be locomotion at all.'' (Author/AL)

  16. Technetium-99m-methylene diphosphonate uptake in the fetal skeleton at 30 weeks gestation

    SciTech Connect

    McKenzie, A.F.; Budd, R.S.; Yang, C.

    1994-08-01

    Retention of {sup 99m}Tc-MDP in the fetal skeleton and placenta at 30 and 32 wk gestation was observed during bone scan examination of the maternal skeleton for staging of malignant tumors. The implications and significance of these observations are discussed. 8 refs., 2 figs., 1 tab.

  17. Morphological plasticity of the coral skeleton under CO2-driven seawater acidification

    PubMed Central

    Tambutté, E.; Venn, A. A.; Holcomb, M.; Segonds, N.; Techer, N.; Zoccola, D.; Allemand, D.; Tambutté, S.

    2015-01-01

    Ocean acidification causes corals to calcify at reduced rates, but current understanding of the underlying processes is limited. Here, we conduct a mechanistic study into how seawater acidification alters skeletal growth of the coral Stylophora pistillata. Reductions in colony calcification rates are manifested as increases in skeletal porosity at lower pH, while linear extension of skeletons remains unchanged. Inspection of the microstructure of skeletons and measurements of pH at the site of calcification indicate that dissolution is not responsible for changes in skeletal porosity. Instead, changes occur by enlargement of corallite-calyxes and thinning of associated skeletal elements, constituting a modification in skeleton architecture. We also detect increases in the organic matrix protein content of skeletons formed under lower pH. Overall, our study reveals that seawater acidification not only causes decreases in calcification, but can also cause morphological change of the coral skeleton to a more porous and potentially fragile phenotype. PMID:26067341

  18. Shape similarity comparison of protein CPK models based on improved L₁-medial skeleton.

    PubMed

    Qin, S W; Li, Z; Jin, Y; Zhang, S P

    2014-01-01

    We propose a new method to analyse the similarity of protein CPK models. In the proposed method we first construct the skeleton of protein models by an improved L1-medial skeleton extraction. The skeleton information is then used to form a local radius descriptor. Finally, the shape similarity of protein models is compared by using the local radius descriptor based on the absolute degree of grey incidence. Experimental results show that the improved L1-medial skeleton of protein models can describe the shapes of the protein models well. The local descriptor based on the skeleton combined with the absolute degree of grey incidence shows satisfactory performance for comparing the shape similarity of protein CPK models.

  19. The Principal and Reference Letters.

    ERIC Educational Resources Information Center

    Smith, Agnes E.; Permuth, Steve; Gray, David L.

    1999-01-01

    Requests to write letters of reference for former teachers can be legally problematic. Principals should know relevant state laws; have employees sign a release from liability; provide only factual information; maintain fair personnel files; avoid telephone recommendations; disclose information on a need-to-know basis; and avoid performance…

  20. Principal Leadership in Taiwan Schools

    ERIC Educational Resources Information Center

    Shouse, Roger C.; Lin, Kuan-Pei

    2010-01-01

    During the past two decades, Taiwan's Ministry of Education has responded to globalization by restructuring school curricular, instructional, and decision making practices along western lines in an attempt to attain legitimacy on the world stage. As a result, Taiwanese principals, once kings within their schools, now must share power with other…

  1. Do Principals Engineer the Job?

    ERIC Educational Resources Information Center

    Faulkner, Raymond T. B.; O'Reilly, Robert R.

    Based on Fiedler's Contingency Model of Leadership Effectiveness and Leader-Match program, this study's hypothesis is that experienced school principals increase their effectiveness by changing key organizational variables to suit their personal leadership styles. Following V. D. McNamara's application of Fiedler's contingency model in a study of…

  2. Preparing Elementary Principals for Preschool

    ERIC Educational Resources Information Center

    Bish, Marion; Shore, Rebecca; Shue, Pamela

    2011-01-01

    "Surprise! Here come the preschoolers." Thousands of elementary principals are receiving a similar message from their supervisors as the concept of universal preschool is propelled to the forefront of the national education agenda. School districts across the country are being infused with wide varieties of federal- and state-funded early…

  3. Toward Understanding Principals' Hiring Practices

    ERIC Educational Resources Information Center

    Engel, Mimi; Curran, F. Chris

    2016-01-01

    Purpose: The purpose of this paper is to explore variation across principals in terms of the number and types of strategies they engage in to find teachers to fill the vacancies in their schools. The practices that the authors consider to be strategic are aligned with the district's goals and objectives for teacher recruitment.…

  4. The Need for Principal Renewal: The Promise of Sustaining Principals through Principal-to-Principal Reflective Practice

    ERIC Educational Resources Information Center

    Drago-Severson, Eleanor

    2012-01-01

    Background/Context: Given the challenging complexity of the modern principalship--including high-stakes testing, standards-based reform, increased accountability, and severe budget cuts--practitioners and scholars emphasize the urgency of supporting principals' stress-relief and renewal. Purpose/Objective/Research Question/Focus of Study: This…

  5. The Principal as Tech Leader

    ERIC Educational Resources Information Center

    Demski, Jennifer

    2012-01-01

    The conventional wisdom in education is that any school reform--be it curriculum, instruction, assessment, or teacher professionalism--is most likely to take hold in schools that have strong leadership. The same holds true for technology. The most successful implementation of technology programs takes place in schools where the principal sees him…

  6. How Principals Support Teacher Effectiveness

    ERIC Educational Resources Information Center

    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…

  7. Selective principal component regression analysis of fluorescence hyperspectral image to assess aflatoxin contamination in corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Selective principal component regression analysis (SPCR) uses a subset of the original image bands for principal component transformation and regression. For optimal band selection before the transformation, this paper used genetic algorithms (GA). In this case, the GA process used the regression co...

  8. Quantifying the deformation of the red blood cell skeleton in shear flow

    NASA Astrophysics Data System (ADS)

    Peng, Zhangli; Zhu, Qiang

    2012-02-01

    To quantitatively predict the response of red blood cell (RBC) membrane in shear flow, we carried out multiphysics simulations by coupling a three-level multiscale approach of RBC membranes with a Boundary Element Method (BEM) for surrounding flows. Our multiscale approach includes a model of spectrins with the domain unfolding feature, a molecular-based model of the junctional complex with detailed protein connectivity and a whole cell Finite Element Method (FEM) model with the bilayer-skeleton friction derived from measured transmembrane protein diffusivity based on the Einstein-Stokes relation. Applying this approach, we investigated the bilayer-skeleton slip and skeleton deformation of healthy RBCs and RBCs with hereditary spherocytosis anemia during tank-treading motion. Compared with healthy cells, cells with hereditary spherocytosis anemia sustain much larger skeleton-bilayer slip and area deformation of the skeleton due to deficiency of transmembrane proteins. This leads to extremely low skeleton density and large bilayer-skeleton interaction force, both of which may cause bilayer loss. This finding suggests a possible mechanism of the development of hereditary spherocytosis anemia.

  9. Dual embryonic origin and patterning of the pharyngeal skeleton in the axolotl (Ambystoma mexicanum).

    PubMed

    Sefton, Elizabeth M; Piekarski, Nadine; Hanken, James

    2015-01-01

    The impressive morphological diversification of vertebrates was achieved in part by innovation and modification of the pharyngeal skeleton. Extensive fate mapping in amniote models has revealed a primarily cranial neural crest derivation of the pharyngeal skeleton. Although comparable fate maps of amphibians produced over several decades have failed to document a neural crest derivation of ventromedial elements in these vertebrates, a recent report provides evidence of a mesodermal origin of one of these elements, basibranchial 2, in the axolotl. We used a transgenic labeling protocol and grafts of labeled cells between GFP+ and white embryos to derive a fate map that describes contributions of both cranial neural crest and mesoderm to the axolotl pharyngeal skeleton, and we conducted additional experiments that probe the mechanisms that underlie mesodermal patterning. Our fate map confirms a dual embryonic origin of the pharyngeal skeleton in urodeles, including derivation of basibranchial 2 from mesoderm closely associated with the second heart field. Additionally, heterotopic transplantation experiments reveal lineage restriction of mesodermal cells that contribute to pharyngeal cartilage. The mesoderm-derived component of the pharyngeal skeleton appears to be particularly sensitive to retinoic acid (RA): administration of exogenous RA leads to loss of the second basibranchial, but not the first. Neural crest was undoubtedly critical in the evolution of the vertebrate pharyngeal skeleton, but mesoderm may have played a central role in forming ventromedial elements, in particular. When and how many times during vertebrate phylogeny a mesodermal contribution to the pharyngeal skeleton evolved remain to be resolved. PMID:25963195

  10. Dual embryonic origin and patterning of the pharyngeal skeleton in the axolotl (Ambystoma mexicanum).

    PubMed

    Sefton, Elizabeth M; Piekarski, Nadine; Hanken, James

    2015-01-01

    The impressive morphological diversification of vertebrates was achieved in part by innovation and modification of the pharyngeal skeleton. Extensive fate mapping in amniote models has revealed a primarily cranial neural crest derivation of the pharyngeal skeleton. Although comparable fate maps of amphibians produced over several decades have failed to document a neural crest derivation of ventromedial elements in these vertebrates, a recent report provides evidence of a mesodermal origin of one of these elements, basibranchial 2, in the axolotl. We used a transgenic labeling protocol and grafts of labeled cells between GFP+ and white embryos to derive a fate map that describes contributions of both cranial neural crest and mesoderm to the axolotl pharyngeal skeleton, and we conducted additional experiments that probe the mechanisms that underlie mesodermal patterning. Our fate map confirms a dual embryonic origin of the pharyngeal skeleton in urodeles, including derivation of basibranchial 2 from mesoderm closely associated with the second heart field. Additionally, heterotopic transplantation experiments reveal lineage restriction of mesodermal cells that contribute to pharyngeal cartilage. The mesoderm-derived component of the pharyngeal skeleton appears to be particularly sensitive to retinoic acid (RA): administration of exogenous RA leads to loss of the second basibranchial, but not the first. Neural crest was undoubtedly critical in the evolution of the vertebrate pharyngeal skeleton, but mesoderm may have played a central role in forming ventromedial elements, in particular. When and how many times during vertebrate phylogeny a mesodermal contribution to the pharyngeal skeleton evolved remain to be resolved.

  11. Experimental Approach Reveals the Role of alx1 in the Evolution of the Echinoderm Larval Skeleton

    PubMed Central

    Koga, Hiroyuki; Fujitani, Haruka; Morino, Yoshiaki; Miyamoto, Norio; Tsuchimoto, Jun; Shibata, Tomoko F.; Nozawa, Masafumi; Shigenobu, Shuji; Ogura, Atsushi; Tachibana, Kazunori; Kiyomoto, Masato; Amemiya, Shonan; Wada, Hiroshi

    2016-01-01

    Over the course of evolution, the acquisition of novel structures has ultimately led to wide variation in morphology among extant multicellular organisms. Thus, the origins of genetic systems for new morphological structures are a subject of great interest in evolutionary biology. The larval skeleton is a novel structure acquired in some echinoderm lineages via the activation of the adult skeletogenic machinery. Previously, VEGF signaling was suggested to have played an important role in the acquisition of the larval skeleton. In the present study, we compared expression patterns of Alx genes among echinoderm classes to further explore the factors involved in the acquisition of a larval skeleton. We found that the alx1 gene, originally described as crucial for sea urchin skeletogenesis, may have also played an essential role in the evolution of the larval skeleton. Unlike those echinoderms that have a larval skeleton, we found that alx1 of starfish was barely expressed in early larvae that have no skeleton. When alx1 overexpression was induced via injection of alx1 mRNA into starfish eggs, the expression patterns of certain genes, including those possibly involved in skeletogenesis, were altered. This suggested that a portion of the skeletogenic program was induced solely by alx1. However, we observed no obvious external phenotype or skeleton. We concluded that alx1 was necessary but not sufficient for the acquisition of the larval skeleton, which, in fact, requires several genetic events. Based on these results, we discuss how the larval expression of alx1 contributed to the acquisition of the larval skeleton in the putative ancestral lineage of echinoderms. PMID:26866800

  12. Experimental Approach Reveals the Role of alx1 in the Evolution of the Echinoderm Larval Skeleton.

    PubMed

    Koga, Hiroyuki; Fujitani, Haruka; Morino, Yoshiaki; Miyamoto, Norio; Tsuchimoto, Jun; Shibata, Tomoko F; Nozawa, Masafumi; Shigenobu, Shuji; Ogura, Atsushi; Tachibana, Kazunori; Kiyomoto, Masato; Amemiya, Shonan; Wada, Hiroshi

    2016-01-01

    Over the course of evolution, the acquisition of novel structures has ultimately led to wide variation in morphology among extant multicellular organisms. Thus, the origins of genetic systems for new morphological structures are a subject of great interest in evolutionary biology. The larval skeleton is a novel structure acquired in some echinoderm lineages via the activation of the adult skeletogenic machinery. Previously, VEGF signaling was suggested to have played an important role in the acquisition of the larval skeleton. In the present study, we compared expression patterns of Alx genes among echinoderm classes to further explore the factors involved in the acquisition of a larval skeleton. We found that the alx1 gene, originally described as crucial for sea urchin skeletogenesis, may have also played an essential role in the evolution of the larval skeleton. Unlike those echinoderms that have a larval skeleton, we found that alx1 of starfish was barely expressed in early larvae that have no skeleton. When alx1 overexpression was induced via injection of alx1 mRNA into starfish eggs, the expression patterns of certain genes, including those possibly involved in skeletogenesis, were altered. This suggested that a portion of the skeletogenic program was induced solely by alx1. However, we observed no obvious external phenotype or skeleton. We concluded that alx1 was necessary but not sufficient for the acquisition of the larval skeleton, which, in fact, requires several genetic events. Based on these results, we discuss how the larval expression of alx1 contributed to the acquisition of the larval skeleton in the putative ancestral lineage of echinoderms. PMID:26866800

  13. Experimental Approach Reveals the Role of alx1 in the Evolution of the Echinoderm Larval Skeleton.

    PubMed

    Koga, Hiroyuki; Fujitani, Haruka; Morino, Yoshiaki; Miyamoto, Norio; Tsuchimoto, Jun; Shibata, Tomoko F; Nozawa, Masafumi; Shigenobu, Shuji; Ogura, Atsushi; Tachibana, Kazunori; Kiyomoto, Masato; Amemiya, Shonan; Wada, Hiroshi

    2016-01-01

    Over the course of evolution, the acquisition of novel structures has ultimately led to wide variation in morphology among extant multicellular organisms. Thus, the origins of genetic systems for new morphological structures are a subject of great interest in evolutionary biology. The larval skeleton is a novel structure acquired in some echinoderm lineages via the activation of the adult skeletogenic machinery. Previously, VEGF signaling was suggested to have played an important role in the acquisition of the larval skeleton. In the present study, we compared expression patterns of Alx genes among echinoderm classes to further explore the factors involved in the acquisition of a larval skeleton. We found that the alx1 gene, originally described as crucial for sea urchin skeletogenesis, may have also played an essential role in the evolution of the larval skeleton. Unlike those echinoderms that have a larval skeleton, we found that alx1 of starfish was barely expressed in early larvae that have no skeleton. When alx1 overexpression was induced via injection of alx1 mRNA into starfish eggs, the expression patterns of certain genes, including those possibly involved in skeletogenesis, were altered. This suggested that a portion of the skeletogenic program was induced solely by alx1. However, we observed no obvious external phenotype or skeleton. We concluded that alx1 was necessary but not sufficient for the acquisition of the larval skeleton, which, in fact, requires several genetic events. Based on these results, we discuss how the larval expression of alx1 contributed to the acquisition of the larval skeleton in the putative ancestral lineage of echinoderms.

  14. Using Telecommunications for Principals' Professional Development.

    ERIC Educational Resources Information Center

    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…

  15. Principal's Time Use and School Effectiveness

    ERIC Educational Resources Information Center

    Horng, Eileen Lai; Klasik, Daniel; Loeb, Susanna

    2010-01-01

    School principals have complex jobs. To better understand the work lives of principals, this study uses observational time use data for all high school principals in one district. This article examines the relationship between the time principals spent on different types of activities and school outcomes, including student achievement, teacher and…

  16. Developing Principal Instructional Leadership through Collaborative Networking

    ERIC Educational Resources Information Center

    Cone, Mariah Bahar

    2010-01-01

    This study examines what occurs when principals of urban schools meet together to learn and improve their instructional leadership in collaborative principal networks designed to support, sustain, and provide ongoing principal capacity building. Principal leadership is considered second only to teaching in its ability to improve schools, yet few…

  17. Lifeworld or Systemsworld: What Guides Novice Principals?

    ERIC Educational Resources Information Center

    Nelson, Sarah W.; de la Colina, Maria G.; Boone, Michael D.

    2008-01-01

    Purpose: This paper aims to contribute to the literature on principal preparation by examining the experiences of novice principals and what their experiences mean for principal preparation in the USA. Design/methodology/approach: The researchers employed qualitative methods to examine the experiences of four novice principals over a two-year…

  18. The Changing Role of the School Principal

    ERIC Educational Resources Information Center

    Ediger, Marlow

    2014-01-01

    The role of the school principal has changed much in the recent intervening years. He/she was formerly thought of as a manager and management of the local school. Today the principal is seen as the leader of curriculum improvement. School principals must believe in pupils being able to achieve optimally in school and in life. Principals must…

  19. Paleopathologies of the vertebral column in medieval skeletons.

    PubMed

    Hofmann, Maria Ines; Böni, Thomas; Alt, Kurt W; Woitek, Ulrich; Rühli, Frank J

    2008-03-01

    Paleopathological data provide valuable information about health, longevity and mortality in earlier human populations. We investigated the incidence of spinal pathologies on 54 individuals (1045 vertebrae and 18 sacral bones) that belong to a medieval skeletal series discovered in the Dalheim monastery (Northwest Germany) and compared them with contemporary and recent populations. The skeletons were analyzed with anthropological methods (sex and age determination), by macroscopic inspection, and, if pathologies of the spine and the sacrum were visible, also by X-ray. We investigated evidence of trauma, specific and nonspecific infectious diseases, joint diseases, tumors, and congenital as well as metabolic disorders. Radiocarbon determination of four samples of different specimens was also undertaken revealing a historic dating of ca. 1050 AD. The most common pathological findings were degenerative changes of the spine found in 29 individuals (53.3%). Examples of infections of the spine were rare (0.8% of all vertebrae). There were no cases of traumatic injuries of the spine. The prevalence of spondylosis deformans, the most commonly found type of pathology was found to be higher in the lumbar region, in males as well as in individuals of low stature.

  20. The dynamics of secretion during sea urchin embryonic skeleton formation

    SciTech Connect

    Wilt, Fred H.

    2008-05-01

    Skeleton formation involves secretion of massive amounts of mineral precursor, usually a calcium salt, and matrix proteins, many of which are deposited on, or even occluded within, the mineral. The cell biological underpinnings of this secretion and subsequent assembly of the biomineralized skeletal element is not well understood. We ask here what is the relationship of the trafficking and secretion of the mineral and matrix within the primary mesenchyme cells of the sea urchin embryo, cells that deposit the endoskeletal spicule. Fluorescent labeling of intracellular calcium deposits show mineral precursors are present in granules visible by light microscopy, from whence they are deposited in the endoskeletal spicule, especially at its tip. In contrast, two different matrix proteins tagged with GFP are present in smaller post-Golgi vesicles only seen by electron microscopy, and the secreted protein are only incorporated into the spicule in the vicinity of the cell of origin. The matrix protein, SpSM30B, is post-translationally modified during secretion, and this processing continues after its incorporation into the spicule. Our findings also indicate that the mineral precursor and two well characterized matrix proteins are trafficked by different cellular routes.

  1. Ocean acidification causes structural deformities in juvenile coral skeletons

    PubMed Central

    Foster, Taryn; Falter, James L.; McCulloch, Malcolm T.; Clode, Peta L.

    2016-01-01

    Rising atmospheric CO2 is causing the oceans to both warm and acidify, which could reduce the calcification rates of corals globally. Successful coral recruitment and high rates of juvenile calcification are critical to the replenishment and ultimate viability of coral reef ecosystems. Although elevated Pco2 (partial pressure of CO2) has been shown to reduce the skeletal weight of coral recruits, the structural changes caused by acidification during initial skeletal deposition are unknown. We show, using high-resolution three-dimensional x-ray microscopy, that ocean acidification (Pco2 ~900 μatm, pH ~7.7) not only causes reduced overall mineral deposition but also a deformed and porous skeletal structure in newly settled coral recruits. In contrast, elevated temperature (+3°C) had little effect on skeletal formation except to partially mitigate the effects of elevated Pco2. The striking structural deformities we observed show that new recruits are at significant risk, being unable to effectively build their skeletons in the Pco2 conditions predicted to occur for open ocean surface waters under a “business-as-usual” emissions scenario [RCP (representative concentration pathway) 8.5] by the year 2100. PMID:26989776

  2. Ocean acidification causes structural deformities in juvenile coral skeletons.

    PubMed

    Foster, Taryn; Falter, James L; McCulloch, Malcolm T; Clode, Peta L

    2016-02-01

    Rising atmospheric CO2 is causing the oceans to both warm and acidify, which could reduce the calcification rates of corals globally. Successful coral recruitment and high rates of juvenile calcification are critical to the replenishment and ultimate viability of coral reef ecosystems. Although elevated Pco2 (partial pressure of CO2) has been shown to reduce the skeletal weight of coral recruits, the structural changes caused by acidification during initial skeletal deposition are unknown. We show, using high-resolution three-dimensional x-ray microscopy, that ocean acidification (Pco2 ~900 μatm, pH ~7.7) not only causes reduced overall mineral deposition but also a deformed and porous skeletal structure in newly settled coral recruits. In contrast, elevated temperature (+3°C) had little effect on skeletal formation except to partially mitigate the effects of elevated Pco2. The striking structural deformities we observed show that new recruits are at significant risk, being unable to effectively build their skeletons in the Pco2 conditions predicted to occur for open ocean surface waters under a "business-as-usual" emissions scenario [RCP (representative concentration pathway) 8.5] by the year 2100. PMID:26989776

  3. Dipole relaxation in erythrocyte membrane: involvement of spectrin skeleton.

    PubMed

    Ivanov, I T; Paarvanova, B; Slavov, T

    2012-12-01

    Polarization of spectrin-actin undermembrane skeleton of red blood cell (RBC) plasma membranes was studied by impedance spectroscopy. Relatedly, dielectric spectra of suspensions that contained RBCs of humans, mammals (bovine, horse, dog, cat) and birds (turkey, pigeon, duck), and human RBC ghost membranes were continuously obtained during heating from 20 to 70°C. Data for the complex admittance and capacitance were used to derive the suspension resistance, R, and capacitance, C, as well as the energy loss as a function of temperature. As in previous studies, two irreversible temperature-induced transitions in the human RBC plasma membrane were detected at 49.5°C and at 60.7°C (at low heating rate). The transition at 49.5°C was evident from the abrupt changes in R, and C and the fall in the energy loss, due to dipole relaxation. For the erythrocytes of indicated species the changes in R and C displayed remarkable and similar frequency profiles within the 0.05-13MHz domain. These changes were subdued after cross-linking of membranes by diamide (0.3-1.3mM) and glutaraldehyde (0.1-0.4%) and at the presence of glycerol (10%). Based on the above results and previous reports, the dielectric changes at 49.5°C were related to dipole relaxation and segmental mobility of spectrin cytoskeleton. The results open the possibility for selective dielectric thermolysis of cell cytoskeleton.

  4. Origin and genetic evolution of the vertebrate skeleton.

    PubMed

    Wada, Hiroshi

    2010-02-01

    The current understanding of the origin and evolution of the genetic cassette for the vertebrate skeletal system is reviewed. Molecular phylogenetic analyses of fibrillar collagen genes, which encode the main component of both cartilage and mineralized bone, suggest that genome duplications in vertebrate ancestors were essential for producing distinct collagen fibers for cartilage and mineralized bone. Several data Indicate co-expression of the ancestral copy of fibrillar collagen with the SoxE and Runx transcription factors. Therefore, the genetic cassette may have already existed in protochordate ancestors, and may operate in the development of the pharyngeal gill skeleton. Accompanied by genome duplications in vertebrate ancestors, this genetic cassette may have also been duplicated and co-opted for cartilage and bone. Subsequently, the genetic cassette for cartilage recruited novel genetic material via domain shuffling. Aggrecan, acquired by means of domain shuffling, performs an essential role in cartilage as a shock absorber. In contrast, the cassette for bone recruited new genetic material produced by tandem duplication of the SPARC/osteonectin genes. Some of the duplicated copies of SPARC/osteonectin became secretory Cabinding phosphoproteins (SCPPs) performing a central role in mineralization by regulating the calcium phosphate concentration. Comparative genome analysis revealed similar molecular evolutionary histories for the genetic cassettes for cartilage and bone, namely duplication of the ancestral genetic cassette and recruitment of novel genetic material.

  5. The life cycle of chondrocytes in the developing skeleton

    PubMed Central

    Shum, Lillian; Nuckolls, Glen

    2002-01-01

    Cartilage serves multiple functions in the developing embryo and in postnatal life. Genetic mutations affecting cartilage development are relatively common and lead to skeletal malformations, dysfunction or increased susceptibility to disease or injury. Characterization of these mutations and investigation of the molecular pathways in which these genes function have contributed to an understanding of the mechanisms regulating skeletal patterning, chondrogenesis, endochondral ossification and joint formation. Extracellular growth and differentiation factors including bone morphogenetic proteins, fibroblast growth factors, parathyroid hormone-related peptide, extracellular matrix components, and members of the hedgehog and Wnt families provide important signals for the regulation of cell proliferation, differentiation and apoptosis. Transduction of these signals within the developing mesenchymal cells and chondrocytes results in changes in gene expression mediated by transcription factors including Smads, Msx2, Sox9, signal transducer and activator of transcription (STAT), and core-binding factor alpha 1. Further investigation of the interactions of these signaling pathways will contribute to an understanding of cartilage growth and development, and will allow for the development of strategies for the early detection, prevention and treatment of diseases and disorders affecting the skeleton. PMID:11879545

  6. Ocean acidification causes structural deformities in juvenile coral skeletons.

    PubMed

    Foster, Taryn; Falter, James L; McCulloch, Malcolm T; Clode, Peta L

    2016-02-01

    Rising atmospheric CO2 is causing the oceans to both warm and acidify, which could reduce the calcification rates of corals globally. Successful coral recruitment and high rates of juvenile calcification are critical to the replenishment and ultimate viability of coral reef ecosystems. Although elevated Pco2 (partial pressure of CO2) has been shown to reduce the skeletal weight of coral recruits, the structural changes caused by acidification during initial skeletal deposition are unknown. We show, using high-resolution three-dimensional x-ray microscopy, that ocean acidification (Pco2 ~900 μatm, pH ~7.7) not only causes reduced overall mineral deposition but also a deformed and porous skeletal structure in newly settled coral recruits. In contrast, elevated temperature (+3°C) had little effect on skeletal formation except to partially mitigate the effects of elevated Pco2. The striking structural deformities we observed show that new recruits are at significant risk, being unable to effectively build their skeletons in the Pco2 conditions predicted to occur for open ocean surface waters under a "business-as-usual" emissions scenario [RCP (representative concentration pathway) 8.5] by the year 2100.

  7. Canaliculi in the tessellated skeleton of cartilaginous fishes

    SciTech Connect

    Dean, M.N.; Socha, J.J.; Hall, B.K.; Summers, A.P.

    2010-08-04

    The endoskeletal elements of sharks and rays are comprised of an uncalcified, hyaline cartilage-like core overlain by a thin fibro-ceramic layer of mineralized hexagonal tiles (tesserae) adjoined by intertesseral fibers. The basic spatial relationships of the constituent tissues (unmineralized cartilage, mineralized cartilage, fibrous tissue) are well-known - endoskeletal tessellation is a long-recognized synapomorphy of elasmobranch fishes - but a high-resolution and three-dimensional (3D) understanding of their interactions has been hampered by difficulties in sample preparation and lack of technologies adequate for visualizing microstructure and microassociations. We used cryo-electron microscopy and synchrotron radiation tomography to investigate tessellated skeleton ultrastructure but without damage to the delicate relationships between constituent tissues or to the tesserae themselves. The combination of these techniques allowed visualization of never before appreciated internal structures, namely passages connecting the lacunar spaces within tesserae. These intratesseral 'canaliculi' link consecutive lacunar spaces into long lacunar strings, radiating outward from the center of tesserae. The continuity of extracellular matrix throughout the canalicular network may explain how chondrocytes in tesserae remain vital despite encasement in mineral. Extracellular fluid exchange may also permit transmission of nutrients, and mechanical and mineralization signals among chondrocytes, in a manner similar to the canalicular network in bone. These co-adapted mechanisms for the facilitated exchange of extracellular material suggest a level of parallelism in early chondrocyte and osteocyte evolution.

  8. Phase-shifting interferometry based on principal component analysis.

    PubMed

    Vargas, J; Quiroga, J Antonio; Belenguer, T

    2011-04-15

    An asynchronous phase-shifting method based on principal component analysis (PCA) is presented. No restrictions about the background, modulation, and phase shifts are necessary. The presented method is very fast and needs very low computational requirements, so it can be used with very large images and/or very large image sets. The method is based on obtaining two quadrature signals by the PCA algorithm. We have applied the proposed method to simulated and experimental interferograms, obtaining satisfactory results.

  9. Late Pleistocene human skeleton and mtDNA link Paleoamericans and modern Native Americans.

    PubMed

    Chatters, James C; Kennett, Douglas J; Asmerom, Yemane; Kemp, Brian M; Polyak, Victor; Blank, Alberto Nava; Beddows, Patricia A; Reinhardt, Eduard; Arroyo-Cabrales, Joaquin; Bolnick, Deborah A; Malhi, Ripan S; Culleton, Brendan J; Erreguerena, Pilar Luna; Rissolo, Dominique; Morell-Hart, Shanti; Stafford, Thomas W

    2014-05-16

    Because of differences in craniofacial morphology and dentition between the earliest American skeletons and modern Native Americans, separate origins have been postulated for them, despite genetic evidence to the contrary. We describe a near-complete human skeleton with an intact cranium and preserved DNA found with extinct fauna in a submerged cave on Mexico's Yucatan Peninsula. This skeleton dates to between 13,000 and 12,000 calendar years ago and has Paleoamerican craniofacial characteristics and a Beringian-derived mitochondrial DNA (mtDNA) haplogroup (D1). Thus, the differences between Paleoamericans and Native Americans probably resulted from in situ evolution rather than separate ancestry. PMID:24833392

  10. The second complete skeleton of Archidiskodon meridionalis (Elephantidae, Proboscidea) from the Stavropol Region, Russia

    NASA Astrophysics Data System (ADS)

    Maschenko, E. N.; Schvyreva, A. K.; Kalmykov, N. P.

    2011-08-01

    The skeleton of Archidiskodon meridionalis ( Nesti, 1825) from the Rodionovo locality (Stavropol Administrative Region, Russia) is described in detail. It represents the second discovery of an almost complete skeleton of a fossil elephant in the Northern Caucasus. The age of the fossil is estimated as Early Pleistocene (upper Apsheronian, late Middle Villafranchian). Attribution of the skeleton to this species, widely distributed in Eurasia during the Late Pliocene-Early Pleistocene, is based on the tooth characters (M3/m3 enamel thickness and lamellar frequency). Validity of the genus Archidiskodon Pohlig, 1888 is discussed.

  11. The membrane skeleton of erythrocytes: models of its effect on lateral diffusion.

    PubMed

    Saxton, M J

    1990-01-01

    The membrane skeleton, a network of structural proteins attached to the cytoplasmic surface of the plasma membrane, hinders lateral diffusion of integral proteins. 2. In some types of cells, such as epithelial cells and nerve cells, the obstruction of lateral diffusion by the membrane skeleton is one of the mechanisms by which proteins are localized to domains on the cell surface. 3. The effect of the membrane skeleton on lateral diffusion may involve steric hindrance, transient binding or both. Three pictures of the effect are reviewed, the discrete barrier model, the continuous barrier model and the transient binding model. 4. Experiments to distinguish the models are discussed.

  12. Late Pleistocene human skeleton and mtDNA link Paleoamericans and modern Native Americans.

    PubMed

    Chatters, James C; Kennett, Douglas J; Asmerom, Yemane; Kemp, Brian M; Polyak, Victor; Blank, Alberto Nava; Beddows, Patricia A; Reinhardt, Eduard; Arroyo-Cabrales, Joaquin; Bolnick, Deborah A; Malhi, Ripan S; Culleton, Brendan J; Erreguerena, Pilar Luna; Rissolo, Dominique; Morell-Hart, Shanti; Stafford, Thomas W

    2014-05-16

    Because of differences in craniofacial morphology and dentition between the earliest American skeletons and modern Native Americans, separate origins have been postulated for them, despite genetic evidence to the contrary. We describe a near-complete human skeleton with an intact cranium and preserved DNA found with extinct fauna in a submerged cave on Mexico's Yucatan Peninsula. This skeleton dates to between 13,000 and 12,000 calendar years ago and has Paleoamerican craniofacial characteristics and a Beringian-derived mitochondrial DNA (mtDNA) haplogroup (D1). Thus, the differences between Paleoamericans and Native Americans probably resulted from in situ evolution rather than separate ancestry.

  13. Principal components analysis competitive learning.

    PubMed

    López-Rubio, Ezequiel; Ortiz-de-Lazcano-Lobato, Juan Miguel; Muñoz-Pérez, José; Gómez-Ruiz, José Antonio

    2004-11-01

    We present a new neural model that extends the classical competitive learning by performing a principal components analysis (PCA) at each neuron. This model represents an improvement with respect to known local PCA methods, because it is not needed to present the entire data set to the network on each computing step. This allows a fast execution while retaining the dimensionality-reduction properties of the PCA. Furthermore, every neuron is able to modify its behavior to adapt to the local dimensionality of the input distribution. Hence, our model has a dimensionality estimation capability. The experimental results we present show the dimensionality-reduction capabilities of the model with multisensor images.

  14. Correction: A Co(2+)-selective and chirality-sensitive supermolecular metallohydrogel with a nanofiber network skeleton.

    PubMed

    Wang, Xiaojuan; He, Ting; Yang, Lan; Wu, Huiqiong; Zhang, Rui; Zhang, Zhenzhu; Shen, Rujuan; Xiang, Juan; Zhang, Yi; Wei, Chuanwan

    2016-04-21

    Correction for 'A Co(2+)-selective and chirality-sensitive supermolecular metallohydrogel with a nanofiber network skeleton' by Xiaojuan Wang et al., Nanoscale, 2016, DOI: 10.1039/c6nr00822d. PMID:27021200

  15. Skeleton extraction and phase interpolation for single ESPI fringe pattern based on the partial differential equations.

    PubMed

    Zhang, Fang; Wang, Danyu; Xiao, Zhitao; Geng, Lei; Wu, Jun; Xu, Zhenbei; Sun, Jiao; Wang, Jinjiang; Xi, Jiangtao

    2015-11-16

    A novel phase extraction method for single electronic speckle pattern interferometry (ESPI) fringes is proposed. The partial differential equations (PDEs) are used to extract the skeletons of the gray-scale fringe and to interpolate the whole-field phase values based on skeleton map. Firstly, the gradient vector field (GVF) of the initial fringe is adjusted by an anisotropic PDE. Secondly, the skeletons of the fringe are extracted combining the divergence property of the adjusted GVF. After assigning skeleton orders, the whole-field phase information is interpolated by the heat conduction equation. The validity of the proposed method is verified by computer-simulated and experimentally obtained poor-quality ESPI fringe patterns. PMID:26698445

  16. Iridium-catalyzed reductive carbon-carbon bond cleavage reaction on a curved pyridylcorannulene skeleton.

    PubMed

    Tashiro, Shohei; Yamada, Mihoko; Shionoya, Mitsuhiko

    2015-04-27

    The cleavage of CC bonds in π-conjugated systems is an important method for controlling their shape and coplanarity. An efficient way for the cleavage of an aromatic CC bond in a typical buckybowl corannulene skeleton is reported. The reaction of 2-pyridylcorannulene with a catalytic amount of IrCl3 ⋅n H2 O in ethylene glycol at 250 °C resulted in a structural transformation from the curved corannulene skeleton to a strain-free flat benzo[ghi]fluoranthene skeleton through a site-selective CC cleavage reaction. This cleavage reaction was found to be driven by both the coordination of the 2-pyridyl substituent to iridium and the relief of strain in the curved corannulene skeleton. This finding should facilitate the design of carbon nanomaterials based on CC bond cleavage reactions.

  17. Skeletons Out of the Closet: The Case of the Missing 162%.

    ERIC Educational Resources Information Center

    Pressnall, Bob

    1995-01-01

    Describes one teacher's difficulty in getting his eighth-grade students to revise their writing. Discusses his successful use of writing "skeletons" to help define what revision is and to teach a structure for one type of revision. (SR)

  18. Descriptions of the lower limb skeleton of Homo floresiensis.

    PubMed

    Jungers, W L; Larson, S G; Harcourt-Smith, W; Morwood, M J; Sutikna, T; Due Awe, Rokhus; Djubiantono, T

    2009-11-01

    Bones of the lower extremity have been recovered for up to nine different individuals of Homo floresiensis - LB1, LB4, LB6, LB8, LB9, LB10, LB11, LB13, and LB14. LB1 is represented by a bony pelvis (damaged but now repaired), femora, tibiae, fibulae, patellae, and numerous foot bones. LB4/2 is an immature right tibia lacking epiphyses. LB6 includes a fragmentary metatarsal and two pedal phalanges. LB8 is a nearly complete right tibia (shorter than that of LB1). LB9 is a fragment of a hominin femoral diaphysis. LB10 is a proximal hallucal phalanx. LB11 includes pelvic fragments and a fragmentary metatarsal. LB13 is a patellar fragment, and LB14 is a fragment of an acetabulum. All skeletal remains recovered from Liang Bua were extremely fragile, and some were badly damaged when they were removed temporarily from Jakarta. At present, virtually all fossil materials have been returned, stabilized, and hardened. These skeletal remains are described and illustrated photographically. The lower limb skeleton exhibits a uniquely mosaic pattern, with many primitive-like morphologies; we have been unable to find this combination of ancient and derived (more human-like) features in either healthy or pathological modern humans, regardless of body size. Bilateral asymmetries are slight in the postcranium, and muscle markings are clearly delineated on all bones. The long bones are robust, and the thickness of their cortices is well within the ranges seen in healthy modern humans. LB1 is most probably a female based on the shape of her greater sciatic notch, and the marked degree of lateral iliac flaring recalls that seen in australopithecines such as "Lucy" (AL 288-1). The metatarsus has a human-like robusticity formula, but the proximal pedal phalanges are relatively long and robust (and slightly curved). The hallux is fully adducted, but we suspect that a medial longitudinal arch was absent. PMID:19062072

  19. Scaling of the appendicular skeleton of the giraffe (Giraffa camelopardalis).

    PubMed

    van Sittert, Sybrand; Skinner, John; Mitchell, Graham

    2015-05-01

    Giraffes have remarkably long and slender limb bones, but it is unknown how they grow with regard to body mass, sex, and neck length. In this study, we measured the length, mediolateral (ML) diameter, craniocaudal (CC) diameter and circumference of the humerus, radius, metacarpus, femur, tibia, and metatarsus in 10 fetuses, 21 females, and 23 males of known body masses. Allometric exponents were determined and compared. We found the average bone length increased from 340 ± 50 mm at birth to 700 ± 120 mm at maturity, while average diameters increased from 30 ± 3 to 70 ± 11 mm. Fetal bones increased with positive allometry in length (relative to body mass) and in diameter (relative to body mass and length). In postnatal giraffes bone lengths and diameters increased iso- or negatively allometric relative to increases in body mass, except for the humerus CC diameter which increased with positive allometry. Humerus circumference also increased with positive allometry, that of the radius and tibia isometrically and the femur and metapodials with negative allometry. Relative to increases in bone length, both the humerus and femur widened with positive allometry. In the distal limb bones, ML diameters increased isometrically (radius, metacarpus) or positively allometric (tibia, metatarsus) while the corresponding CC widths increased with negative allometry and isometrically, respectively. Except for the humerus and femur, exponents were not significantly different between corresponding front and hind limb segments. We concluded that the patterns of bone growth in males and females are identical. In fetuses, the growth of the appendicular skeleton is faster than it is after birth which is a pattern opposite to that reported for the neck. Allometric exponents seemed unremarkable compared to the few species described previously, and pointed to the importance of neck elongation rather than leg elongation during evolution. Nevertheless, the front limb bones

  20. Dressed skeleton expansion and the coupling scale ambiguity problem

    SciTech Connect

    Lu, Hung Jung

    1992-09-01

    Perturbative expansions in quantum field theories are usually expressed in powers of a coupling constant. In principle, the infinite sum of the expansion series is independent of the renormalization scale of the coupling constant. In practice, there is a remnant dependence of the truncated series on the renormalization scale. This scale ambiguity can severely restrict the predictive power of theoretical calculations. The dressed skeleton expansion is developed as a calculational method which avoids the coupling scale ambiguity problem. In this method, physical quantities are expressed as functional expansions in terms of a coupling vertex function. The arguments of the vertex function are given by the physical momenta of each process. These physical momenta effectively replace the unspecified renormalization scale and eliminate the ambiguity problem. This method is applied to various field theoretical models and its main features and limitations are explored. For quantum chromodynamics, an expression for the running coupling constant of the three-gluon vertex is obtained. The effective coupling scale of this vertex is shown to be essentially given by {mu}{sup 2} {approximately} Q{sub min}{sup 2}Q{sub med}{sup 2}/Q{sub max}{sup 2} where Q{sub min}{sup 2}Q{sub med}{sup 2}/Q{sub max}{sup 2} are respectively the smallest, the next-to-smallest and the largest scale among the three gluon virtualities. This functional form suggests that the three-gluon vertex becomes non-perturbative at asymmetric momentum configurations. Implications for four-jet physics is discussed.

  1. Descriptions of the lower limb skeleton of Homo floresiensis.

    PubMed

    Jungers, W L; Larson, S G; Harcourt-Smith, W; Morwood, M J; Sutikna, T; Due Awe, Rokhus; Djubiantono, T

    2009-11-01

    Bones of the lower extremity have been recovered for up to nine different individuals of Homo floresiensis - LB1, LB4, LB6, LB8, LB9, LB10, LB11, LB13, and LB14. LB1 is represented by a bony pelvis (damaged but now repaired), femora, tibiae, fibulae, patellae, and numerous foot bones. LB4/2 is an immature right tibia lacking epiphyses. LB6 includes a fragmentary metatarsal and two pedal phalanges. LB8 is a nearly complete right tibia (shorter than that of LB1). LB9 is a fragment of a hominin femoral diaphysis. LB10 is a proximal hallucal phalanx. LB11 includes pelvic fragments and a fragmentary metatarsal. LB13 is a patellar fragment, and LB14 is a fragment of an acetabulum. All skeletal remains recovered from Liang Bua were extremely fragile, and some were badly damaged when they were removed temporarily from Jakarta. At present, virtually all fossil materials have been returned, stabilized, and hardened. These skeletal remains are described and illustrated photographically. The lower limb skeleton exhibits a uniquely mosaic pattern, with many primitive-like morphologies; we have been unable to find this combination of ancient and derived (more human-like) features in either healthy or pathological modern humans, regardless of body size. Bilateral asymmetries are slight in the postcranium, and muscle markings are clearly delineated on all bones. The long bones are robust, and the thickness of their cortices is well within the ranges seen in healthy modern humans. LB1 is most probably a female based on the shape of her greater sciatic notch, and the marked degree of lateral iliac flaring recalls that seen in australopithecines such as "Lucy" (AL 288-1). The metatarsus has a human-like robusticity formula, but the proximal pedal phalanges are relatively long and robust (and slightly curved). The hallux is fully adducted, but we suspect that a medial longitudinal arch was absent.

  2. Beta-catenin--a supporting role in the skeleton.

    PubMed

    Case, Natasha; Rubin, Janet

    2010-06-01

    In the last 5 years a role for beta-catenin in the skeleton has been cemented. Beginning with mutations in the Lrp5 receptor that control beta-catenin canonical downstream signals, and progressing to transgenic models with bone-specific alteration of beta-catenin, research has shown that beta-catenin is required for normal bone development. A cell critical to bone in which beta-catenin activity determines function is the marrow-derived mesenchymal stem cell (MSC), where sustained beta-catenin prevents its distribution into adipogenic lineage. beta-Catenin actions are less well understood in mature osteoblasts: while beta-catenin contributes to control of osteoclastic bone resorption via alteration of the osteoprotegerin/RANKL ratio, a specific regulatory role during osteoblast bone synthesis has not yet been determined. The proven ability of mechanical factors to prevent beta-catenin degradation and induce nuclear translocation through Lrp-independent mechanisms suggests processes by which exercise might modulate bone mass via control of lineage allocation, in particular, by preventing precursor distribution into the adipocyte pool. Effects resulting from mechanical activation of beta-catenin in mature osteoblasts and osteocytes likely modulate bone resorption, but whether beta-catenin is involved in osteoblast synthetic function remains to be proven for both mechanical and soluble mediators. As beta-catenin appears to support the downstream effects of multiple osteogenic factors, studies clarifying when and where beta-catenin effects occur will be relevant for translational approaches aimed at preventing bone loss and terminal adipogenic conversion.

  3. Determination of Race from the Skeleton through Forensic Anthropological Methods.

    PubMed

    Church, M S

    1995-06-01

    Metric and morphological techniques employed by forensic anthropologists for determination of race are reviewed. Included are several studies which examine cranial morphological techniques such as presence of the oval window of the inner ear, which occurs more frequently in Whites than in Native Americans; or the shape of the alveolar region which distinguishes between Asian, African, and North American Indian groups. A table of common cranial morphologic traits is presented. Metric techniques have also been used to determine race from the skull. Regression equations derived from measurements of the cranial base indicate a 70-90% accuracy for classifying Blacks and Whites, while multivariate discriminant functions for discriminating Blacks, Whites, and Native Americans correctly classify 82.6% of the males and 88.1% of the females. FORDISC, a computer program developed at the University of Tennessee, is another metric technique reviewed that not only distinguishes Whites, Blacks, and Native Americans but also male Hispanics, Chinese, and Vietnamese. Platycnemia, femoral curvature and other morphological attributes of the post-cranial skeleton may be used in support of a racial determination; however, several investigators have turned to post-cranial elements not only to use in support of cranial findings but for use when cranial information is not available. As a result, several discriminant functions from measurements of the pelvis, femur, tibia or combinations of these elements have been developed. Accuracy for these techniques varies from 57% to 95%, depending on the sample and technique used. Other aspects of the femur, such as the diameter of the neck, height of the intercondylar notch and femoral curvature, have been measured for assessment of race. Also included is a brief historical survey of race and current thoughts on the concept of race. PMID:26270337

  4. Space flight and the skeleton: lessons for the earthbound

    NASA Technical Reports Server (NTRS)

    Bikle, D. D.; Halloran, B. P.; Morey-Holton, E.

    1997-01-01

    Loss of bone during extended space flight has long been a concern that could limit the ability of humans to explore the universe. Surprisingly, the available data do not support the concept that weightlessness leads inexorably to a depleted skeleton unable to withstand the stress of a return to a 1-g environment. Nevertheless, some bone loss does occur, especially in those bones most stressed by gravity prior to flight, which provides confirmation of the proposal formulated over a century ago by Julius Wolff that mechanical stress determines the form and function of bone. Although the phenomenon of bone loss with skeletal unloading, whether by space flight or immobilization or just taking a load off your feet (literally) is well established, the mechanisms by which bone senses load and adjusts to it are not so clear. What actually is the stimulus, and what are the sensors? What are the target cells? How do the sensors communicate the message into the cells, and by what pathways do the cells respond? What is the role of endocrine, factors vs. paracrine or autocrine factors in mediating or modulating the response? None of these questions has been answered with certainty, but, as will become apparent in this review, we have some clues directing us to the answers. Although the focus of this review concerns space flight, it seems highly likely that the mechanisms mediating the transmission of mechanical load to changes in bone formation and resorption apply equally well to all forms of disuse osteoporosis and are likely to be the same mechanisms affected by other etiologies of osteoporosis.

  5. Spaceflight and the skeleton: lessons for the earthbound

    NASA Technical Reports Server (NTRS)

    Bikle, D. D.; Halloran, B. P.; Morey-Holton, E.

    1997-01-01

    Loss of bone during extended space flight has long been a concern that could limit the ability of humans to explore the universe. Surprisingly the available data do not support the concept that weightlessness leads inexorably to a depleted skeleton unable to withstand the stress of a return to a 1g environment. Nevertheless, some bone loss does occur especially in those bones most stressed by gravity prior to flight, providing confirmation of the proposal formulated over a century ago by Julius Wolff that mechanical stress determines the form and function of bone. Although the phenomenon of bone loss with skeletal unloading, whether by space flight or immobilization or just taking a load off your feet (literally) is well established, the mechanisms by which bone senses load and adjusts to it are not so clear. What actually is the stimulus and what are the sensors? What are the target cells? How do the sensors communicate the message into the cells, and by what pathways do the cells respond? What is the role of endocrine factors versus paracrine or autocrine factors in mediating or modulating the response? None of these questions has been answered with certainty, but as will become apparent in this review, we have some clues directing us to the answers. Although the focus of this review concerns space flight, it seems highly likely that the mechanisms mediating the transmission of mechanical load to changes in bone formation and resorption apply equally well to all forms of disuse osteoporosis, and are likely to be the same mechanisms affected by other etiologies of osteoporosis.

  6. Scaling of the appendicular skeleton of the giraffe (Giraffa camelopardalis).

    PubMed

    van Sittert, Sybrand; Skinner, John; Mitchell, Graham

    2015-05-01

    Giraffes have remarkably long and slender limb bones, but it is unknown how they grow with regard to body mass, sex, and neck length. In this study, we measured the length, mediolateral (ML) diameter, craniocaudal (CC) diameter and circumference of the humerus, radius, metacarpus, femur, tibia, and metatarsus in 10 fetuses, 21 females, and 23 males of known body masses. Allometric exponents were determined and compared. We found the average bone length increased from 340 ± 50 mm at birth to 700 ± 120 mm at maturity, while average diameters increased from 30 ± 3 to 70 ± 11 mm. Fetal bones increased with positive allometry in length (relative to body mass) and in diameter (relative to body mass and length). In postnatal giraffes bone lengths and diameters increased iso- or negatively allometric relative to increases in body mass, except for the humerus CC diameter which increased with positive allometry. Humerus circumference also increased with positive allometry, that of the radius and tibia isometrically and the femur and metapodials with negative allometry. Relative to increases in bone length, both the humerus and femur widened with positive allometry. In the distal limb bones, ML diameters increased isometrically (radius, metacarpus) or positively allometric (tibia, metatarsus) while the corresponding CC widths increased with negative allometry and isometrically, respectively. Except for the humerus and femur, exponents were not significantly different between corresponding front and hind limb segments. We concluded that the patterns of bone growth in males and females are identical. In fetuses, the growth of the appendicular skeleton is faster than it is after birth which is a pattern opposite to that reported for the neck. Allometric exponents seemed unremarkable compared to the few species described previously, and pointed to the importance of neck elongation rather than leg elongation during evolution. Nevertheless, the front limb bones

  7. Transformation of echinoid Mg calcite skeletons by heating

    NASA Astrophysics Data System (ADS)

    Dickson, J. A. D.

    2001-02-01

    Interambularcral plates of echinoid Heterocentrotus trigonarius, composed of Mg calcite 1 (≈14 mol% MgCO 3), were heated in three timed series of experiments at 300°C. Dried plate fragments and fragments with added water were heated separately in pressurized bombs. X-ray powder diffractometry, unit cell dimensions, and phase compositions are used to monitor reaction progress. After 10 h heating in the bombs dolomite (43.5 mol% MgCO 3) and Mg calcite appear (4-7 mol% MgCO 3); by 20 h all Mg calcite 1 is consumed, and at 120 h dolomite composition has evolved to ≈47 mol% MgCO 3 and calcite to ≈2 mol% MgCO 3. Whole plates heated at 300°C in an open muffle furnace develop dolomite (≈42 mol% MgCO 3) and Mg calcite 2 (≈6 mol% MgCO 3) after 10 h and remain compositionally invariant throughout subsequent heating to 620 h. Limited skeletal water catalyzes the early reaction but escapes from the open furnace and consequently reaction ceases after ≈10 h. The experimentally produced dolomite has relative Mg-Ca ordering of 75% to 79%. The stabilization of echinoid Mg calcite by heating at 300°C to a mixture of dolomite and calcite occurs through a dissolution/precipitation reaction. The alteration fabric produced within the stereom consists of irregularly shaped, branched dolomite crystals > 5 μm homoaxially set in a calcite 2 (bomb) or Mg calcite 2 (furnace) matrix. Round and tubular pores 1 to 5 μm are randomly distributed throughout this fabric. The stereom pore system remains intact during furnace heating but is destroyed during heating in bombs. The texture of experimentally stabilized echinoid skeletons is different from that of fossil echinoderms that are composed of microrhomic dolomite homoaxially set in a single calcite crystal.

  8. Enzalutamide Reduces the Bone Mass in the Axial But Not the Appendicular Skeleton in Male Mice.

    PubMed

    Wu, Jianyao; Movérare-Skrtic, Sofia; Börjesson, Anna E; Lagerquist, Marie K; Sjögren, Klara; Windahl, Sara H; Koskela, Antti; Grahnemo, Louise; Islander, Ulrika; Wilhelmson, Anna S; Tivesten, Åsa; Tuukkanen, Juha; Ohlsson, Claes

    2016-02-01

    Testosterone is a crucial regulator of the skeleton, but the role of the androgen receptor (AR) for the maintenance of the adult male skeleton is unclear. In the present study, the role of the AR for bone metabolism and skeletal growth after sexual maturation was evaluated by means of the drug enzalutamide, which is a new AR antagonist used in the treatment of prostate cancer patients. Nine-week-old male mice were treated with 10, 30, or 100 mg/kg·d of enzalutamide for 21 days or were surgically castrated and were compared with vehicle-treated gonadal intact mice. Although orchidectomy reduced the cortical bone thickness and trabecular bone volume fraction in the appendicular skeleton, these parameters were unaffected by enzalutamide. In contrast, both enzalutamide and orchidectomy reduced the bone mass in the axial skeleton as demonstrated by a reduced lumbar spine areal bone mineral density (P < .001) and trabecular bone volume fraction in L5 vertebrae (P < .001) compared with vehicle-treated gonadal intact mice. A compression test of the L5 vertebrae revealed that the mechanical strength in the axial skeleton was significantly reduced by enzalutamide (maximal load at failure -15.3% ± 3.5%; P < .01). The effects of enzalutamide in the axial skeleton were associated with a high bone turnover. In conclusion, enzalutamide reduces the bone mass in the axial but not the appendicular skeleton in male mice after sexual maturation. We propose that the effect of testosterone on the axial skeleton in male mice is mainly mediated via the AR.

  9. Sparse principal component analysis in medical shape modeling

    NASA Astrophysics Data System (ADS)

    Sjöstrand, Karl; Stegmann, Mikkel B.; Larsen, Rasmus

    2006-03-01

    Principal component analysis (PCA) is a widely used tool in medical image analysis for data reduction, model building, and data understanding and exploration. While PCA is a holistic approach where each new variable is a linear combination of all original variables, sparse PCA (SPCA) aims at producing easily interpreted models through sparse loadings, i.e. each new variable is a linear combination of a subset of the original variables. One of the aims of using SPCA is the possible separation of the results into isolated and easily identifiable effects. This article introduces SPCA for shape analysis in medicine. Results for three different data sets are given in relation to standard PCA and sparse PCA by simple thresholding of small loadings. Focus is on a recent algorithm for computing sparse principal components, but a review of other approaches is supplied as well. The SPCA algorithm has been implemented using Matlab and is available for download. The general behavior of the algorithm is investigated, and strengths and weaknesses are discussed. The original report on the SPCA algorithm argues that the ordering of modes is not an issue. We disagree on this point and propose several approaches to establish sensible orderings. A method that orders modes by decreasing variance and maximizes the sum of variances for all modes is presented and investigated in detail.

  10. The Virtual Skeleton Database: An Open Access Repository for Biomedical Research and Collaboration

    PubMed Central

    Bonaretti, Serena; Pfahrer, Marcel; Niklaus, Roman; Büchler, Philippe

    2013-01-01

    Background Statistical shape models are widely used in biomedical research. They are routinely implemented for automatic image segmentation or object identification in medical images. In these fields, however, the acquisition of the large training datasets, required to develop these models, is usually a time-consuming process. Even after this effort, the collections of datasets are often lost or mishandled resulting in replication of work. Objective To solve these problems, the Virtual Skeleton Database (VSD) is proposed as a centralized storage system where the data necessary to build statistical shape models can be stored and shared. Methods The VSD provides an online repository system tailored to the needs of the medical research community. The processing of the most common image file types, a statistical shape model framework, and an ontology-based search provide the generic tools to store, exchange, and retrieve digital medical datasets. The hosted data are accessible to the community, and collaborative research catalyzes their productivity. Results To illustrate the need for an online repository for medical research, three exemplary projects of the VSD are presented: (1) an international collaboration to achieve improvement in cochlear surgery and implant optimization, (2) a population-based analysis of femoral fracture risk between genders, and (3) an online application developed for the evaluation and comparison of the segmentation of brain tumors. Conclusions The VSD is a novel system for scientific collaboration for the medical image community with a data-centric concept and semantically driven search option for anatomical structures. The repository has been proven to be a useful tool for collaborative model building, as a resource for biomechanical population studies, or to enhance segmentation algorithms. PMID:24220210

  11. Genetic algorithms

    NASA Technical Reports Server (NTRS)

    Wang, Lui; Bayer, Steven E.

    1991-01-01

    Genetic algorithms are mathematical, highly parallel, adaptive search procedures (i.e., problem solving methods) based loosely on the processes of natural genetics and Darwinian survival of the fittest. Basic genetic algorithms concepts are introduced, genetic algorithm applications are introduced, and results are presented from a project to develop a software tool that will enable the widespread use of genetic algorithm technology.

  12. Histology and affinity of anaspids, and the early evolution of the vertebrate dermal skeleton

    PubMed Central

    Keating, Joseph N.; Donoghue, Philip C. J.

    2016-01-01

    The assembly of the gnathostome bodyplan constitutes a formative episode in vertebrate evolutionary history, an interval in which the mineralized skeleton and its canonical suite of cell and tissue types originated. Fossil jawless fishes, assigned to the gnathostome stem-lineage, provide an unparalleled insight into the origin and evolution of the skeleton, hindered only by uncertainty over the phylogenetic position and evolutionary significance of key clades. Chief among these are the jawless anaspids, whose skeletal composition, a rich source of phylogenetic information, is poorly characterized. Here we survey the histology of representatives spanning anaspid diversity and infer their generalized skeletal architecture. The anaspid dermal skeleton is composed of odontodes comprising spheritic dentine and enameloid, overlying a basal layer of acellular parallel fibre bone containing an extensive shallow canal network. A recoded and revised phylogenetic analysis using equal and implied weights parsimony resolves anaspids as monophyletic, nested among stem-gnathostomes. Our results suggest the anaspid dermal skeleton is a degenerate derivative of a histologically more complex ancestral vertebrate skeleton, rather than reflecting primitive simplicity. Hypotheses that anaspids are ancestral skeletonizing lampreys, or a derived lineage of jawless vertebrates with paired fins, are rejected. PMID:26962140

  13. Topology adaptive vessel network skeleton extraction with novel medialness measuring function.

    PubMed

    Zhu, Wen-Bo; Li, Bin; Tian, Lian-Fang; Li, Xiang-Xia; Chen, Qing-Lin

    2015-09-01

    Vessel tree skeleton extraction is widely applied in vascular structure segmentation, however, conventional approaches often suffer from the adjacent interferences and poor topological adaptability. To avoid these problems, a robust, topology adaptive tree-like structure skeleton extraction framework is proposed in this paper. Specifically, to avoid the adjacent interferences, a local message passing procedure called Gaussian affinity voting (GAV) is proposed to realize adaptive scale-growing of vessel voxels. Then the medialness measuring function (MMF) based on GAV, namely GAV-MMF, is constructed to extract medialness patterns robustly. In order to improve topological adaptability, a level-set graph embedded with GAV-MMF is employed to build initial curve skeletons without any user interaction. Furthermore, the GAV-MMF is embedded in stretching open active contours (SOAC) to drive the initial curves to the expected location, maintaining smoothness and continuity. In addition, to provide an accurate and smooth final skeleton tree topology, topological checks and skeleton network reconfiguration is proposed. The continuity and scalability of this method is validated experimentally on synthetic and clinical images for multi-scale vessels. Experimental results show that the proposed method achieves acceptable topological adaptability for skeleton extraction of vessel trees. PMID:26134626

  14. Dissection and Flat-mounting of the Threespine Stickleback Branchial Skeleton.

    PubMed

    Ellis, Nicholas A; Miller, Craig T

    2016-05-07

    The posterior pharyngeal segments of the vertebrate head give rise to the branchial skeleton, the primary site of food processing in fish. The morphology of the fish branchial skeleton is matched to a species' diet. Threespine stickleback fish (Gasterosteus aculeatus) have emerged as a model system to study the genetic and developmental basis of evolved differences in a variety of traits. Marine populations of sticklebacks have repeatedly colonized countless new freshwater lakes and creeks. Adaptation to the new diet in these freshwater environments likely underlies a series of craniofacial changes that have evolved repeatedly in independently derived freshwater populations. These include three major patterning changes to the branchial skeleton: reductions in the number and length of gill raker bones, increases in pharyngeal tooth number, and increased branchial bone lengths. Here we describe a detailed protocol to dissect and flat-mount the internal branchial skeleton in threespine stickleback fish. Dissection of the entire three-dimensional branchial skeleton and mounting it flat into a largely two-dimensional prep allows for the easy visualization and quantification of branchial skeleton morphology. This dissection method is inexpensive, fast, relatively easy, and applicable to a wide variety of fish species. In sticklebacks, this efficient method allows the quantification of skeletal morphology in genetic crosses to map genomic regions controlling craniofacial patterning.

  15. Topology adaptive vessel network skeleton extraction with novel medialness measuring function.

    PubMed

    Zhu, Wen-Bo; Li, Bin; Tian, Lian-Fang; Li, Xiang-Xia; Chen, Qing-Lin

    2015-09-01

    Vessel tree skeleton extraction is widely applied in vascular structure segmentation, however, conventional approaches often suffer from the adjacent interferences and poor topological adaptability. To avoid these problems, a robust, topology adaptive tree-like structure skeleton extraction framework is proposed in this paper. Specifically, to avoid the adjacent interferences, a local message passing procedure called Gaussian affinity voting (GAV) is proposed to realize adaptive scale-growing of vessel voxels. Then the medialness measuring function (MMF) based on GAV, namely GAV-MMF, is constructed to extract medialness patterns robustly. In order to improve topological adaptability, a level-set graph embedded with GAV-MMF is employed to build initial curve skeletons without any user interaction. Furthermore, the GAV-MMF is embedded in stretching open active contours (SOAC) to drive the initial curves to the expected location, maintaining smoothness and continuity. In addition, to provide an accurate and smooth final skeleton tree topology, topological checks and skeleton network reconfiguration is proposed. The continuity and scalability of this method is validated experimentally on synthetic and clinical images for multi-scale vessels. Experimental results show that the proposed method achieves acceptable topological adaptability for skeleton extraction of vessel trees.

  16. Stress-free state of the red blood cell membrane and the deformation of its skeleton.

    PubMed

    Svelc, Tjaša; Svetina, Saša

    2012-06-01

    The response of a red blood cell (RBC) to deformation depends on its membrane, a composite of a lipid bilayer and a skeleton, which is a closed, two-dimensional network of spectrin tetramers as its bonds. The deformation of the skeleton and its lateral redistribution are studied in terms of the RBC resting state for a fixed geometry of the RBC, partially aspirated into a micropipette. The geometry of the RBC skeleton in its initial state is taken to be either two concentric circles, a references biconcave shape or a sphere. It is assumed that in its initial state the skeleton is distributed laterally in a homogeneous manner with its bonds either unstressed, presenting its stress-free state, or prestressed. The lateral distribution was calculated using a variational calculation. It was assumed that the spectrin tetramer bonds exhibit a linear elasticity. The results showed a significant effect of the initial skeleton geometry on its lateral distribution in the deformed state. The proposed model is used to analyze the measurements of skeleton extension ratios by the method of applying two modes of RBC micropipette aspiration.

  17. Histology and affinity of anaspids, and the early evolution of the vertebrate dermal skeleton.

    PubMed

    Keating, Joseph N; Donoghue, Philip C J

    2016-03-16

    The assembly of the gnathostome bodyplan constitutes a formative episode in vertebrate evolutionary history, an interval in which the mineralized skeleton and its canonical suite of cell and tissue types originated. Fossil jawless fishes, assigned to the gnathostome stem-lineage, provide an unparalleled insight into the origin and evolution of the skeleton, hindered only by uncertainty over the phylogenetic position and evolutionary significance of key clades. Chief among these are the jawless anaspids, whose skeletal composition, a rich source of phylogenetic information, is poorly characterized. Here we survey the histology of representatives spanning anaspid diversity and infer their generalized skeletal architecture. The anaspid dermal skeleton is composed of odontodes comprising spheritic dentine and enameloid, overlying a basal layer of acellular parallel fibre bone containing an extensive shallow canal network. A recoded and revised phylogenetic analysis using equal and implied weights parsimony resolves anaspids as monophyletic, nested among stem-gnathostomes. Our results suggest the anaspid dermal skeleton is a degenerate derivative of a histologically more complex ancestral vertebrate skeleton, rather than reflecting primitive simplicity. Hypotheses that anaspids are ancestral skeletonizing lampreys, or a derived lineage of jawless vertebrates with paired fins, are rejected.

  18. Observations of the tissue-skeleton interface in the scleractinian coral Stylophora pistillata

    NASA Astrophysics Data System (ADS)

    Tambutté, E.; Allemand, D.; Zoccola, D.; Meibom, A.; Lotto, S.; Caminiti, N.; Tambutté, S.

    2007-09-01

    Recent micro-analytical studies of coral skeletons have led to the discovery that the effects of biology on the skeletal chemical and isotopic composition are not uniform over the skeleton. The aim of the present work was to provide histological observations of the coral tissue at the interface with the skeleton, using Stylophora pistillata as a model, and to discuss these observations in the context of skeletal ultra-structural organization and composition. Several important observations are reported: (1) At all scales of observation, there was a precise morphological correspondence between the tissues and the skeleton. The morphological features of the calicoblastic ectoderm correspond exactly to the shape of individual crystal fiber bundles in the underlying skeleton, indicating that the calicoblastic cell layer is in direct physical contact with the skeletal surface. This is consistent with the previously observed chemical and isotopic composition of the ultra-structural components in the skeleton. (2) The distribution and density of desmocyte cells, which anchor the calicoblastic ectoderm to the skeletal surface, vary spatially and temporally during skeletal growth. (3) The tissue above the coenosteal spines lack endoderm and consists only of ectodermal cell-layers separated by mesoglea. These findings have important implications for models of vital effects in coral skeletal chemistry and isotope composition.

  19. Female Traditional Principals and Co-Principals: Experiences of Role Conflict and Job Satisfaction

    ERIC Educational Resources Information Center

    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…

  20. Principal Recruitment: Assessing Job Pursuit Intentions among Educators Enrolled in Principal Certification Programs

    ERIC Educational Resources Information Center

    Winter, Paul A.; Rinehart, James S.; Keedy, John L.; Bjork, Lars G.

    2007-01-01

    A statewide cadre of principal certification students (N = 516) completed a principal job survey and role-played as applicants for a principal position by completing a principal job evaluation instrument. Significant predictors of principal job rating included the following: self-reported capability to do the job, expected satisfaction with work…

  1. Great Assistant Principals and the (Great) Principals Who Mentor Them: A Practical Guide

    ERIC Educational Resources Information Center

    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…

  2. Magellan: Principal Venus science findings

    NASA Technical Reports Server (NTRS)

    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.

  3. Nonlinear principal component analysis of climate data

    SciTech Connect

    Boyle, J.; Sengupta, S.

    1995-06-01

    This paper presents the details of the nonlinear principal component analysis of climate data. Topic discussed include: connection with principal component analysis; network architecture; analysis of the standard routine (PRINC); and results.

  4. The puzzling presence of calcite in skeletons of modern solitary corals from the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Goffredo, Stefano; Caroselli, Erik; Mezzo, Francesco; Laiolo, Leonardo; Vergni, Patrizia; Pasquini, Luca; Levy, Oren; Zaccanti, Francesco; Tribollet, Aline; Dubinsky, Zvy; Falini, Giuseppe

    2012-05-01

    The skeleton of scleractinian corals is commonly believed to be composed entirely of aragonite due to the current Mg/Ca molar ratio of seawater, which thermodynamically favours the deposition of this polymorph of calcium carbonate (CaCO3). However, some studies have shown that other forms of CaCO3 such as calcite can be present in significant amount (1-20%) inside tropical coral skeletons, significantly impacting paleo-reconstructions of SST or other environmental parameters based on geochemical proxies. This study aims at investigating for the first time, (1) the skeletal composition of two Mediterranean solitary corals, the azooxanthellate Leptopsammia pruvoti and the zooxanthellate Balanophyllia europaea, across their life cycle, (2) the distribution of the different CaCO3 forms inside skeletons, and (3) their implications in paleoclimatology. The origin of the different forms of CaCO3 observed inside studied coral skeletons and their relationships with the species' habitat and ecological strategies are also discussed. CaCO3 composition of L. pruvoti and B. europaea was investigated at six sites located along the Italian coasts. Skeleton composition was studied by means of X-ray powder diffraction and Fourier transform infrared spectroscopy. A significant amount of calcite (1-23%) was found in more than 90% of the studied coral skeletons, in addition to aragonite. This calcite was preferentially located in the basal and intermediate areas than at the oral pole of coral skeletons. Calcite was also mainly located in the epitheca that covered the exposed parts of the coral in its aboral region. Interestingly in B. europaea, the calcite content was negatively correlated with skeleton size (age). The presence of calcite in scleractinian corals may result from different mechanisms: (1) corals may biologically precipitate calcite crystals at their early stages in order to insure their settlement on the substrate of fixation, especially in surgy environments; (2

  5. Clustering of Mueller matrix images for skeletonized structure detection

    NASA Astrophysics Data System (ADS)

    Collet, Christophe; Zallat, Jihad; Takakura, Yoshitate

    2004-04-01

    This paper extends and refines previous work on clustering of polarization-encoded images. The polarization-encoded images used in this work are considered as multidimensional parametric images where a clustering scheme based on Markovian Bayesian inference is applied. Hidden Markov Chains Model (HMCM) and Hidden Hierarchical Markovian Model (HHMM) show to handle effectively Mueller images and give very good results for biological tissues (vegetal leaves). Pretreatments attempting to reduce the image dimensionality based on the Principal Component Analysis (PCA) turns out to be useless for Mueller matrix images.

  6. Preparing Politically Savvy Principals in Ontario, Canada

    ERIC Educational Resources Information Center

    Winton, Sue; Pollock, Katina

    2013-01-01

    Purpose: The aim of the paper is to argue that principal preparation programs should help candidates: recognize the political role of the school principal; develop political skills (including the ability to strategically appropriate policy); and understand that the political approach of the principal influences teaching, learning, relationships,…

  7. 34 CFR 85.995 - Principal.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Principal. 85.995 Section 85.995 Education Office of the Secretary, Department of Education GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 85.995 Principal. Principal means— (a) An officer, director, owner, partner,...

  8. Principals' Collaborative Roles as Leaders for Learning

    ERIC Educational Resources Information Center

    Kitchen, Margaret; Gray, Susan; Jeurissen, Maree

    2016-01-01

    This article draws on data from three multicultural New Zealand primary schools to reconceptualize principals' roles as leaders for learning. In doing so, the writers build on Sinnema and Robinson's (2012) article on goal setting in principal evaluation. Sinnema and Robinson found that even principals hand-picked for their experience fell short on…

  9. Developing Data Analysis Skills in Principals.

    ERIC Educational Resources Information Center

    Polnick, Barbara; Edmonson, Stacey L.

    The work of school principals has become increasingly more complex and demanding. To prepare principals who can meet these challenges, the National Policy Board for Educational Administration (NPBEA) created a training guide, "Principals for Our Changing Schools: Knowledge and Skill Base" (S. Thomson, 1993). This publication reflects the belief…

  10. School Principal Wants to Spearhead Environmental Education

    ERIC Educational Resources Information Center

    Wenzhong, Cheng

    2004-01-01

    In this article, the author discusses the crucial role that a school principal plays in spearheading environmental education. In the execution of environmental education, the principal is not merely a passive supporter and participant; he should go further to be an initiator. The principal must take the initiative and, using his own ideas and his…

  11. Retaining Principals. ERIC Digest Number 147.

    ERIC Educational Resources Information Center

    Hertling, Elizabeth

    This Digest examines the reasons why--outside of retirement--school principals leave their jobs. It also lists strategies districts can employ to retain principals. Many principals exit their profession because of the long hours, the workload and complexity of the job, the unending supervision of evening activities, the minimal pay difference…

  12. Reteniendo los directores (Retaining Principals). ERIC Digest.

    ERIC Educational Resources Information Center

    Hertling, Elizabeth

    This digest in Spanish examines the reasons why--outside of retirement--school principals leave their jobs. It also lists strategies districts can employ to retain principals. Many principals exit their profession because of the long hours, the workload and complexity of the job, the unending supervision of evening activities, the minimal pay…

  13. Leadership Effects: School Principals and Student Outcomes

    ERIC Educational Resources Information Center

    Coelli, Michael; Green, David A.

    2012-01-01

    We identify the effect of individual high school principals on graduation rates and English exam scores using an administrative data set of grade 12 students in BC Canada. Many principals were rotated across schools by districts, permitting isolation of the effect of principals from the effect of schools. We estimate the variance of the…

  14. Principal Connection/Reaching out for Feedback

    ERIC Educational Resources Information Center

    Hoerr, Thomas R.

    2016-01-01

    Schools are remarkably insular institutions, so "Have I improved?" is an especially difficult question for principals. Sure, schools are filled with people. Despite the schoolwide assemblies, faculty meetings, and crowded halls, much of what principals do is unseen and unknown by other adults. A big portion of principals' time is spent…

  15. Principals: What Are Their Roles and Responsibilities?

    ERIC Educational Resources Information Center

    Cisler, Amanda; Bruce, Mary Alice

    2013-01-01

    Collaboration between school counselors and principals is increasingly important in this accountability era. The purpose of this quantitative study was to examine the role of principal as perceived by professional school counselors and principals, both in training and practicing. While similarities were found in two categories: Managing School…

  16. The Awesome Power of the Principal

    ERIC Educational Resources Information Center

    Fullan, Michael

    2010-01-01

    After more than 20 years of vague reference to the principal as instructional leader, progress is finally being made, and the specificity and results are truly awesome. In 1989, William Smith and Richard Andrews wrote a monograph titled "Instructional Leadership: How Principals Make a Difference." In their study of 1,200 school principals, they…

  17. Conversations with Principals: Issues, Values, and Politics

    ERIC Educational Resources Information Center

    Dubin, Andrew E.

    2006-01-01

    "Conversations With Principals: Issues, Values, and Politics" is a unique compilation of interviews with principals at the elementary, middle, and secondary levels. Unlike any other text in Educational Administration, this book allows students the unusual opportunity to experience the inner voice of principals as they discuss the many decisions…

  18. Teacher Supervision Practices and Principals' Characteristics

    ERIC Educational Resources Information Center

    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…

  19. New Principal Coaching as a Safety Net

    ERIC Educational Resources Information Center

    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…

  20. Perceptions of Isolation among High School Principals

    ERIC Educational Resources Information Center

    Howard, Molly P.; Mallory, Barbara J.

    2008-01-01

    This study addressed the perceptions of isolation among high school principals in Georgia. The data collection process, in which interviews were conducted, provided insight into the lived experiences of 10 principals. One of the findings was that high school principals were relieved, in a sense, to discuss their perceptions of the "loneliness"…

  1. The Principal and the Pear Tree.

    ERIC Educational Resources Information Center

    Hoyle, John R.

    1991-01-01

    School principals are in a difficult environment filled with stress and plagued by weak support. Most principals are unprepared for site-based decision making. University professors must take the initiative to use the emerging knowledge base and develop professional studies degree and staff development programs to prepare principals. (24…

  2. Beginning Elementary Principals around the World

    ERIC Educational Resources Information Center

    Garcia-Garduno, Jose Maria; Slater, Charles L.; Lopez-Gorosave, Gema

    2011-01-01

    The paper explores the different circumstances of newly appointed principals around the world. It is a literature review that examines articles from both English-speaking and non-English-speaking countries. Being a novice principal is stressful and even traumatic. Principals appear to feel unprepared for their role. The problem most common to all…

  3. Principals as Assessment Leaders in Rural Schools

    ERIC Educational Resources Information Center

    Renihan, Patrick; Noonan, Brian

    2012-01-01

    This article reports a study of rural school principals' assessment leadership roles and the impact of rural context on their work. The study involved three focus groups of principals serving small rural schools of varied size and grade configuration in three systems. Principals viewed assessment as a matter of teacher accountability and as a…

  4. Gender and Perceptions: Females as Secondary Principals

    ERIC Educational Resources Information Center

    Nogay, Kathleen; Beebe, Robert J.

    2008-01-01

    The purpose of this study was to investigate the perceptions of teachers and supervisors toward the principal leadership behaviors of female secondary principals in Ohio. Principal self-perceptions were also included to complete the study. The literature shows that women continue to be underrepresented in a field in which the majority of…

  5. A New Look at Principal Evaluation

    ERIC Educational Resources Information Center

    Clifford, Matthew; Ross, Steven

    2013-01-01

    This article describes various aspects of school principal evaluation. The authors note that many states and school districts use evaluations that do not consider existing standards for principals or proven practices. It asserts that principal evaluations must be tools for professional capacity building that leads to improved teaching and…

  6. The Principal as Academician: The Renewed Voice.

    ERIC Educational Resources Information Center

    McAvoy, Brenda, Ed.

    This collection of essays was written by principals who participated in the 1986-87 Humanities Seminar sponsored by the Principals' Institute of Georgia State University. The focus was "The Evolution of Intellectual Leadership." The roles of the principal as philosopher, historian, ethnician, writer and team member are examined through the eyes of…

  7. The Principal's Role in Urban School Reform.

    ERIC Educational Resources Information Center

    Carlin, Philip M.

    1992-01-01

    Explores the principal's role in school reform. Attaching express legitimate power to the principal and ensuring that its effective and collaborative use is the most immediate route to reform. An autonomous, accountable, and achieving principal can function in a school reform setting like that of Chicago (Illinois). (SLD)

  8. The K-8 Principal in 1998.

    ERIC Educational Resources Information Center

    Doud, James L.; Keller, Edward P.

    1998-01-01

    The 1998 study of the K-8 principal shows that the principal's role, revolving about staff supervision, student discipline, marketing, and community/political interactions, has become increasingly diverse and complex. The 42% turnover rate will probably continue into the next decade. Today, 42% of K-8 principals are women, compared to 20% in 1988.…

  9. North Carolina School Law: The Principal's Role.

    ERIC Educational Resources Information Center

    Dellinger, Anne M.

    This book outlines the legal aspects of the principal's role in North Carolina and is intended to be used as an instructive and advisory aid when formulating school policy. The principal's legal status, including a definition of authority and employment rights, is discussed. The author delineates the principal's responsibilities for student…

  10. Principal axes for stochastic dynamics

    NASA Astrophysics Data System (ADS)

    Vasconcelos, V. V.; Raischel, F.; Haase, M.; Peinke, J.; Wächter, M.; Lind, P. G.; Kleinhans, D.

    2011-09-01

    We introduce a general procedure for directly ascertaining how many independent stochastic sources exist in a complex system modeled through a set of coupled Langevin equations of arbitrary dimension. The procedure is based on the computation of the eigenvalues and the corresponding eigenvectors of local diffusion matrices. We demonstrate our algorithm by applying it to two examples of systems showing Hopf bifurcation. We argue that computing the eigenvectors associated to the eigenvalues of the diffusion matrix at local mesh points in the phase space enables one to define vector fields of stochastic eigendirections. In particular, the eigenvector associated to the lowest eigenvalue defines the path of minimum stochastic forcing in phase space, and a transform to a new coordinate system aligned with the eigenvectors can increase the predictability of the system.

  11. Groundwater studies: principal aquifer surveys

    USGS Publications Warehouse

    Burow, Karen R.; Belitz, Kenneth

    2014-01-01

    In 1991, the U.S. Congress established the National Water-Quality Assessment (NAWQA) program within the U.S. Geological Survey (USGS) to develop nationally consistent long-term datasets and provide information about the quality of the Nation’s streams and groundwater. The USGS uses objective and reliable data, water-quality models, and systematic scientific studies to assess current water-quality conditions, to identify changes in water quality over time, and to determine how natural factors and human activities affect the quality of streams and groundwater. NAWQA is the only non-regulatory Federal program to perform these types of studies; participation is voluntary. In the third decade (Cycle 3) of the NAWQA program (2013–2023), the USGS will evaluate the quality and availability of groundwater for drinking supply, improve our understanding of where and why water quality is degraded, and assess how groundwater quality could respond to changes in climate and land use. These goals will be addressed through the implementation of a new monitoring component in Cycle 3: Principal Aquifer Surveys.

  12. Estimating how and why Dr Okuda made a complete wooden human skeleton in the Edo era, Japan.

    PubMed

    Baba, Hisao

    2007-03-01

    Probably in 1820 (late Edo era), a human skeleton for medical education was precisely carved from cypress wood, based on a criminal's skeleton, by a craftsman under the supervision of the medical doctor Banri Okuda in Osaka City. By and large, the wooden skeleton shows morphological characteristics usually seen in early middle-aged females of the Edo era. However, the claviculae, distal ends of the femora and the patellae are exceptionally larger than those of a female, implying that the bones of the original model skeleton had already been lost or were deformed before the wooden skeleton was made. Furthermore, the skeleton may not have been used for medical education, but rather for the promotion of European medicine, which was gradually developing in the Edo era.

  13. A unified approach to ent-atisane diterpenes and related alkaloids: synthesis of (-)-methyl atisenoate, (-)-isoatisine, and the hetidine skeleton.

    PubMed

    Cherney, Emily C; Lopchuk, Justin M; Green, Jason C; Baran, Phil S

    2014-09-10

    A unified approach to ent-atisane diterpenes and related atisine and hetidine alkaloids has been developed from ent-kaurane (-)-steviol (1). The conversion of the ent-kaurane skeleton to the ent-atisane skeleton features a Mukaiyama peroxygenation with concomitant cleavage of the C13-C16 bond. Conversion to the atisine skeleton (9) features a C20-selective C-H activation using a Suárez modification of the Hofmann-Löffler-Freytag (HLF) reaction. A cascade sequence involving azomethine ylide isomerization followed by Mannich cyclization forms the C14-C20 bond in the hetidine skeleton (8). Finally, attempts to form the N-C6 bond of the hetisine skeleton (7) with a late-stage HLF reaction are discussed. The synthesis of these skeletons has enabled the completion of (-)-methyl atisenoate (3) and (-)-isoatisine (4).

  14. Dimensionality reduction of collective motion by principal manifolds

    NASA Astrophysics Data System (ADS)

    Gajamannage, Kelum; Butail, Sachit; Porfiri, Maurizio; Bollt, Erik M.

    2015-01-01

    While the existence of low-dimensional embedding manifolds has been shown in patterns of collective motion, the current battery of nonlinear dimensionality reduction methods is not amenable to the analysis of such manifolds. This is mainly due to the necessary spectral decomposition step, which limits control over the mapping from the original high-dimensional space to the embedding space. Here, we propose an alternative approach that demands a two-dimensional embedding which topologically summarizes the high-dimensional data. In this sense, our approach is closely related to the construction of one-dimensional principal curves that minimize orthogonal error to data points subject to smoothness constraints. Specifically, we construct a two-dimensional principal manifold directly in the high-dimensional space using cubic smoothing splines, and define the embedding coordinates in terms of geodesic distances. Thus, the mapping from the high-dimensional data to the manifold is defined in terms of local coordinates. Through representative examples, we show that compared to existing nonlinear dimensionality reduction methods, the principal manifold retains the original structure even in noisy and sparse datasets. The principal manifold finding algorithm is applied to configurations obtained from a dynamical system of multiple agents simulating a complex maneuver called predator mobbing, and the resulting two-dimensional embedding is compared with that of a well-established nonlinear dimensionality reduction method.

  15. Escalation and ecological selectively of mineralogy in the Cambrian Radiation of skeletons

    NASA Astrophysics Data System (ADS)

    Wood, Rachel; Zhuravlev, Andrey Yu.

    2012-12-01

    Assembly of the necessary biochemical machinery for biomineralisation long-predated the appearance and rapid diversification of metazoan skeletons in the late Ediacaran to Middle Cambrian (~ 550-520 million years ago (Ma)), and the independent acquisition of skeletons of differing mineralogies suggests a trigger that conferred selective advantage to possession of a skeleton even though this involved physiological cost. The cost-benefit ratio of biomineralisation has changed over geological time, varying not only with the availability of precursor ions in seawater, but also with evolutionary innovations, as the energy required to produce a skeleton will change as a function of community ecology, particularly with increases in predation pressure. Here, we demonstrate that during the Cambrian Radiation the choice of biomineral was controlled by an interaction between changing seawater chemistry and evolving ecology. The record also reveals the successive skeletonisation of groups with increasing levels of activity from the Ediacaran to Middle Cambrian. The oldest (~ 550-540 Ma) biomineralised organisms were sessile, and preferentially formed low-cost, simple, skeletons of either high-Mg calcite coincident with high mMg:Ca and/or low pCO2 (aragonite seas), or phosphate during with a well-documented phosphogenic event. More elaborate, but tough and protective, aragonitic skeletons appeared from ~ 540 Ma, dominantly in motile benthos (mostly stem- and crown-group Lophotrochozoa). The first low-Mg calcite skeletons of novel organic-rich composite materials (e.g. trilobites) did not appear until the late early Cambrian (~ 526 Ma), coincident with the first onset of low mMg:Ca and/or high pCO2 (calcite seas). Active, bentho-pelagic predatory groups (vertebrates, chaetognaths, some arthropods) appearing mainly in the late early Cambrian preferentially possessed phosphatic skeletons, which were more stable at the low pH ranges of extracellular fluids associated with intense

  16. Hh signaling regulates patterning and morphogenesis of the pharyngeal arch-derived skeleton

    PubMed Central

    Swartz, Mary E.; Nguyen, Van; McCarthy, Neil Q.

    2012-01-01

    The proper function of the craniofacial skeleton requires the proper shaping of many individual skeletal elements. Neural crest cells generate much of the craniofacial skeleton and morphogenesis of skeletal elements occurs in transient, reiterated structures termed pharyngeal arches. The shape of individual elements depends upon intrinsic patterning within the neural crest as well as extrinsic signals to the neural crest from adjacent tissues within the arches. Hedgehog (Hh) signaling is known to play roles in craniofacial development, yet its involvement in intrinsic and extrinsic patterning of the craniofacial skeleton is still not well understood. Here, we show that morphogenetic movements of the pharyngeal arches and patterning of the neural crest require Hh signaling. Loss of Hh signaling, in smoothened (smo) mutants, disrupts the expression of some Dlx genes as well as other markers of dorsal/ventral patterning of the neural crest. Transplantation of wild-type neural crest cells into smo mutants rescues this defect, demonstrating that the neural crest requires reception of Hh signals for proper patterning. Despite the rescue, morphogenesis of the facial skeleton is not fully recovered. Through transplant analyses, we find two additional requirements for Hh signaling. The endoderm requires the reception of Hh signals for proper morphogenetic movements of the pharyngeal arches and the neural crest require the reception of Hh signaling for the activity of a reverse signal that maintains sonic hedgehog expression in the endoderm. Collectively, these results demonstrate that Hh signaling is essential to establish intrinsic and extrinsic patterning information for the craniofacial skeleton. PMID:22709972

  17. Collagen duplicate genes of bone and cartilage participate during regeneration of zebrafish fin skeleton.

    PubMed

    Duran, I; Csukasi, F; Taylor, S P; Krakow, D; Becerra, J; Bombarely, A; Marí-Beffa, M

    2015-01-01

    The zebrafish fin is widely used as a model for skeleton regeneration. For years, the nature of the fin skeleton has been controversial as its extracellular matrix shows hybrid characteristics of both bone and cartilage. The presence of co-orthologs genes also increases the complexity of these tissues. In this article, we have identified and described the expression of fibrillar collagens in zebrafish fin skeleton. We found that genes coding for types I, II, V, XI and XXVII collagens are duplicated, showing in several cases, different expression domains. We also identified specific genomic features, such as the presence of type XXIV collagen and the absence of type III collagen in the zebrafish genome. Our study showed that actinotrichia-forming cells and osteoblasts synthesize a wide variety of these fibrillar collagens during fin regeneration. An intertrichial domain expressing most of the collagens was located in the transition between the mesenchyme condensations of actinotrichia and lepidotrichia and may determine an important niche associated with fin skeleton morphogenesis. We also confirmed the hybrid nature of the fin exoskeleton and provided a complete description of those fibrillar collagens expressed during the formation of the fin skeleton. PMID:26256560

  18. Abstract morphemes and lexical representation: the CV-Skeleton in Arabic.

    PubMed

    Boudelaa, Sami; Marslen-Wilson, William D

    2004-07-01

    Overlaps in form and meaning between morphologically related words have led to ambiguities in interpreting priming effects in studies of lexical organization. In Semitic languages like Arabic, however, linguistic analysis proposes that one of the three component morphemes of a surface word is the CV-Skeleton, an abstract prosodic unit coding the phonological shape of the surface word and its primary syntactic function, which has no surface phonetic content (McCarthy, J. J. (1981). A prosodic theory of non-concatenative morphology, Linguistic Inquiry, 12 373-418). The other two morphemes are proposed to be the vocalic melody, which conveys additional syntactic information, and the root, which defines meaning. In three experiments using masked, cross-modal, and auditory-auditory priming we examined the role of the vocalic melody and the CV-Skeleton as potential morphemic units in the processing and representation of Arabic words. Prime/target pairs sharing the vocalic melody but not the CV-Skeleton consistently failed to prime. In contrast, word pairs sharing only the CV-Skeleton primed reliably throughout, with the amount of priming being as large as that observed between word pattern pairs sharing both vocalic melody and CV-Skeleton. Priming between morphologically related words can be observed when there is no overlap either in meaning or in surface phonetic form.

  19. Static analysis techniques for semiautomatic synthesis of message passing software skeletons

    DOE PAGESBeta

    Sottile, Matthew; Dagit, Jason; Zhang, Deli; Hendry, Gilbert; Dechev, Damian

    2015-06-29

    The design of high-performance computing architectures demands performance analysis of large-scale parallel applications to derive various parameters concerning hardware design and software development. The process of performance analysis and benchmarking an application can be done in several ways with varying degrees of fidelity. One of the most cost-effective ways is to do a coarse-grained study of large-scale parallel applications through the use of program skeletons. The concept of a “program skeleton” that we discuss in this article is an abstracted program that is derived from a larger program where source code that is determined to be irrelevant is removed formore » the purposes of the skeleton. In this work, we develop a semiautomatic approach for extracting program skeletons based on compiler program analysis. Finally, we demonstrate correctness of our skeleton extraction process by comparing details from communication traces, as well as show the performance speedup of using skeletons by running simulations in the SST/macro simulator.« less

  20. Static analysis techniques for semiautomatic synthesis of message passing software skeletons

    SciTech Connect

    Sottile, Matthew; Dagit, Jason; Zhang, Deli; Hendry, Gilbert; Dechev, Damian

    2015-06-29

    The design of high-performance computing architectures demands performance analysis of large-scale parallel applications to derive various parameters concerning hardware design and software development. The process of performance analysis and benchmarking an application can be done in several ways with varying degrees of fidelity. One of the most cost-effective ways is to do a coarse-grained study of large-scale parallel applications through the use of program skeletons. The concept of a “program skeleton” that we discuss in this article is an abstracted program that is derived from a larger program where source code that is determined to be irrelevant is removed for the purposes of the skeleton. In this work, we develop a semiautomatic approach for extracting program skeletons based on compiler program analysis. Finally, we demonstrate correctness of our skeleton extraction process by comparing details from communication traces, as well as show the performance speedup of using skeletons by running simulations in the SST/macro simulator.

  1. Hh signaling regulates patterning and morphogenesis of the pharyngeal arch-derived skeleton.

    PubMed

    Swartz, Mary E; Nguyen, Van; McCarthy, Neil Q; Eberhart, Johann K

    2012-09-01

    The proper function of the craniofacial skeleton requires the proper shaping of many individual skeletal elements. Neural crest cells generate much of the craniofacial skeleton and morphogenesis of skeletal elements occurs in transient, reiterated structures termed pharyngeal arches. The shape of individual elements depends upon intrinsic patterning within the neural crest as well as extrinsic signals to the neural crest from adjacent tissues within the arches. Hedgehog (Hh) signaling is known to play roles in craniofacial development, yet its involvement in intrinsic and extrinsic patterning of the craniofacial skeleton is still not well understood. Here, we show that morphogenetic movements of the pharyngeal arches and patterning of the neural crest require Hh signaling. Loss of Hh signaling, in smoothened (smo) mutants, disrupts the expression of some Dlx genes as well as other markers of dorsal/ventral patterning of the neural crest. Transplantation of wild-type neural crest cells into smo mutants rescues this defect, demonstrating that the neural crest requires reception of Hh signals for proper patterning. Despite the rescue, morphogenesis of the facial skeleton is not fully recovered. Through transplant analyses, we find two additional requirements for Hh signaling. The endoderm requires the reception of Hh signals for proper morphogenetic movements of the pharyngeal arches and the neural crest require the reception of Hh signaling for the activity of a reverse signal that maintains sonic hedgehog expression in the endoderm. Collectively, these results demonstrate that Hh signaling is essential to establish intrinsic and extrinsic patterning information for the craniofacial skeleton.

  2. Lamprey type II collagen and Sox9 reveal an ancient origin of the vertebrate collagenous skeleton.

    PubMed

    Zhang, Guangjun; Miyamoto, Michael M; Cohn, Martin J

    2006-02-28

    Type II collagen is the major cartilage matrix protein in the jawed vertebrate skeleton. Lampreys and hagfishes, by contrast, are thought to have noncollagenous cartilage. This difference in skeletal structure has led to the hypothesis that the vertebrate common ancestor had a noncollagenous skeleton, with type II collagen becoming the predominant cartilage matrix protein after the divergence of jawless fish from the jawed vertebrates approximately 500 million years ago. Here we report that lampreys have two type II collagen (Col2alpha1) genes that are expressed during development of the cartilaginous skeleton. We also demonstrate that the adult lamprey skeleton is rich in Col2alpha1 protein. Furthermore, we have isolated a lamprey orthologue of Sox9, a direct transcriptional regulator of Col2alpha1 in jawed vertebrates, and show that it is coexpressed with both Col2alpha1 genes during skeletal development. These results reveal that the genetic pathway for chondrogenesis in lampreys and gnathostomes is conserved through the activation of cartilage matrix molecules and suggest that a collagenous skeleton evolved surprisingly early in vertebrate evolution.

  3. Collagen duplicate genes of bone and cartilage participate during regeneration of zebrafish fin skeleton.

    PubMed

    Duran, I; Csukasi, F; Taylor, S P; Krakow, D; Becerra, J; Bombarely, A; Marí-Beffa, M

    2015-01-01

    The zebrafish fin is widely used as a model for skeleton regeneration. For years, the nature of the fin skeleton has been controversial as its extracellular matrix shows hybrid characteristics of both bone and cartilage. The presence of co-orthologs genes also increases the complexity of these tissues. In this article, we have identified and described the expression of fibrillar collagens in zebrafish fin skeleton. We found that genes coding for types I, II, V, XI and XXVII collagens are duplicated, showing in several cases, different expression domains. We also identified specific genomic features, such as the presence of type XXIV collagen and the absence of type III collagen in the zebrafish genome. Our study showed that actinotrichia-forming cells and osteoblasts synthesize a wide variety of these fibrillar collagens during fin regeneration. An intertrichial domain expressing most of the collagens was located in the transition between the mesenchyme condensations of actinotrichia and lepidotrichia and may determine an important niche associated with fin skeleton morphogenesis. We also confirmed the hybrid nature of the fin exoskeleton and provided a complete description of those fibrillar collagens expressed during the formation of the fin skeleton.

  4. Posterior midgut epithelial cells differ in their organization of the membrane skeleton from other drosophila epithelia.

    PubMed

    Baumann, O

    2001-11-01

    In epithelial cells, the various components of the membrane skeleton are segregated within specialized subregions of the plasma membrane, thus contributing to the development and stabilization of cell surface polarity. It has previously been shown that, in various Drosophila epithelia, the membrane skeleton components ankyrin and alphabeta-spectrin reside at the lateral surface, whereas alphabeta(H)-spectrin is restricted to the apical domain. By use of confocal immunofluorescence microscopy, the present study characterizes the membrane skeleton of epithelial cells in the posterior midgut, leading to a number of unexpected results. First, ankyrin and alphabeta-spectrin are not detected on the entire lateral surface but appear to be restricted to the apicolateral area, codistributing with fasciclin III at smooth septate junctions. The presumptive ankyrin-binding proteins neuroglian and Na(+),K(+)-ATPase, however, do not colocalize with ankyrin. Second, alphabeta(H)-spectrin is enriched at the apical domain but is also present in lower amounts on the entire lateral surface, colocalizing apicolaterally with ankyrin/alphabeta-spectrin. Finally, despite the absence of zonulae adherentes, F-actin, beta(H)-spectrin, and nonmuscle myosin-II are enriched in the midlateral region. Thus, the model established for the organization of the membrane skeleton in Drosophila epithelia does not hold for the posterior midgut, and there is quite some variability between the different epithelia with respect to the organization of the membrane skeleton.

  5. Application of a Novel Semi-Automatic Technique for Determining the Bilateral Symmetry Plane of the Facial Skeleton of Normal Adult Males.

    PubMed

    Roumeliotis, Grayson; Willing, Ryan; Neuert, Mark; Ahluwalia, Romy; Jenkyn, Thomas; Yazdani, Arjang

    2015-09-01

    The accurate assessment of symmetry in the craniofacial skeleton is important for cosmetic and reconstructive craniofacial surgery. Although there have been several published attempts to develop an accurate system for determining the correct plane of symmetry, all are inaccurate and time consuming. Here, the authors applied a novel semi-automatic method for the calculation of craniofacial symmetry, based on principal component analysis and iterative corrective point computation, to a large sample of normal adult male facial computerized tomography scans obtained clinically (n = 32). The authors hypothesized that this method would generate planes of symmetry that would result in less error when one side of the face was compared to the other than a symmetry plane generated using a plane defined by cephalometric landmarks. When a three-dimensional model of one side of the face was reflected across the semi-automatic plane of symmetry there was less error than when reflected across the cephalometric plane. The semi-automatic plane was also more accurate when the locations of bilateral cephalometric landmarks (eg, frontozygomatic sutures) were compared across the face. The authors conclude that this method allows for accurate and fast measurements of craniofacial symmetry. This has important implications for studying the development of the facial skeleton, and clinical application for reconstruction.

  6. Occlusal load distribution through the cortical and trabecular bone of the human mid-facial skeleton in natural dentition: a three-dimensional finite element study.

    PubMed

    Janovic, Aleksa; Saveljic, Igor; Vukicevic, Arso; Nikolic, Dalibor; Rakocevic, Zoran; Jovicic, Gordana; Filipovic, Nenad; Djuric, Marija

    2015-01-01

    Understanding of the occlusal load distribution through the mid-facial skeleton in natural dentition is essential because alterations in magnitude and/or direction of occlusal forces may cause remarkable changes in cortical and trabecular bone structure. Previous analyses by strain gauge technique, photoelastic and, more recently, finite element (FE) methods provided no direct evidence for occlusal load distribution through the cortical and trabecular bone compartments individually. Therefore, we developed an improved three-dimensional FE model of the human skull in order to clarify the distribution of occlusal forces through the cortical and trabecular bone during habitual masticatory activities. Particular focus was placed on the load transfer through the anterior and posterior maxilla. The results were presented in von Mises stress (VMS) and the maximum principal stress, and compared to the reported FE and strain gauge data. Our qualitative stress analysis indicates that occlusal forces distribute through the mid-facial skeleton along five vertical and two horizontal buttresses. We demonstrated that cortical bone has a priority in the transfer of occlusal load in the anterior maxilla, whereas both cortical and trabecular bone in the posterior maxilla are equally involved in performing this task. Observed site dependence of the occlusal load distribution may help clinicians in creating strategies for implantology and orthodontic treatments. Additionally, the magnitude of VMS in our model was significantly lower in comparison to previous FE models composed only of cortical bone. This finding suggests that both cortical and trabecular bone should be modeled whenever stress will be quantitatively analyzed.

  7. Arborisidine and Arbornamine, Two Monoterpenoid Indole Alkaloids with New Polycyclic Carbon-Nitrogen Skeletons Derived from a Common Pericine Precursor.

    PubMed

    Wong, Suet-Pick; Chong, Kam-Weng; Lim, Kuan-Hon; Lim, Siew-Huah; Low, Yun-Yee; Kam, Toh-Seok

    2016-04-01

    Two new monoterpene indole alkaloids, characterized by previously unencountered natural product skeletons, viz., arborisidine (1), incorporating indolizidine and cyclohexanone moieties fused to an indole unit, and arbornamine (2), incorporating an unprecedented 6/5/6/5/6 "arbornane" skeleton (distinct from the eburnan or tacaman skeleton), were isolated from a Malayan Kopsia arborea. The structures of the alkaloids were determined based on analysis of the NMR and MS data. Possible biogenetic pathways to these alkaloids from a common pericine precursor (3) are presented.

  8. Spatially Weighted Principal Component Analysis for Imaging Classification

    PubMed Central

    Guo, Ruixin; Ahn, Mihye; Zhu, Hongtu

    2014-01-01

    The aim of this paper is to develop a supervised dimension reduction framework, called Spatially Weighted Principal Component Analysis (SWPCA), for high dimensional imaging classification. Two main challenges in imaging classification are the high dimensionality of the feature space and the complex spatial structure of imaging data. In SWPCA, we introduce two sets of novel weights including global and local spatial weights, which enable a selective treatment of individual features and incorporation of the spatial structure of imaging data and class label information. We develop an e cient two-stage iterative SWPCA algorithm and its penalized version along with the associated weight determination. We use both simulation studies and real data analysis to evaluate the finite-sample performance of our SWPCA. The results show that SWPCA outperforms several competing principal component analysis (PCA) methods, such as supervised PCA (SPCA), and other competing methods, such as sparse discriminant analysis (SDA). PMID:26089629

  9. Membrane skeleton orchestrates the platelet glycoprotein (GP) Ib-IX complex clustering and signaling.

    PubMed

    Shang, Dan; Zhang, Zuping; Wang, Qian; Ran, Yali; Shaw, Tanner S; Van, John N; Peng, Yuandong

    2016-10-01

    Platelet glycoprotein Ib-IX complex is affixed to the membrane skeleton through interaction with actin binding protein 280 (ABP-280). We find that removal of the ABP-280 binding sites in GP Ibα cytoplasmic tail has little impact on the complex clustering induced by antibody crosslinking. However, large truncation of the GP Ibα cytoplasmic tail allows the formation of larger patches of the complex, suggesting that an ABP-280 independent force may exist. Besides, we observe that the signaling upon GP Ib-IX clustering is elicited in both membrane lipid domain dependent and independent manner, a choice that relies on how the membrane skeleton interacts with the complex. Our findings suggest a more complex mechanism for how the membrane skeleton regulates the GP Ib-IX function. © 2016 IUBMB Life, 68(10):823-829, 2016. PMID:27634617

  10. A Chinese triconodont mammal and mosaic evolution of the mammalian skeleton.

    PubMed

    Ji, Q; Luo, Z X; Ji, S A; Luo, Z

    1999-03-25

    Here we describe a new triconodont mammal from the Late Jurassic/Early Cretaceous period of Liaoning, China. This new mammal is represented by the best-preserved skeleton known so far for triconodonts which form one of the earliest Mesozoic mammalian groups with high diversity. The postcranial skeleton of this new triconodont shows a mosaic of characters, including a primitive pelvic girdle and hindlimb but a very derived pectoral girdle that is closely comparable to those of derived therians. Given the basal position of this taxon in mammalian phylogeny, its derived pectoral girdle indicates that homoplasies (similarities resulting from independent evolution among unrelated lineages) are as common in the postcranial skeleton as they are in the skull and dentition in the evolution of Mesozoic mammals. Limb structures of the new triconodont indicate that it was probably a ground-dwelling animal. PMID:10192332

  11. A Chinese triconodont mammal and mosaic evolution of the mammalian skeleton.

    PubMed

    Ji, Q; Luo, Z X; Ji, S A; Luo, Z

    1999-03-25

    Here we describe a new triconodont mammal from the Late Jurassic/Early Cretaceous period of Liaoning, China. This new mammal is represented by the best-preserved skeleton known so far for triconodonts which form one of the earliest Mesozoic mammalian groups with high diversity. The postcranial skeleton of this new triconodont shows a mosaic of characters, including a primitive pelvic girdle and hindlimb but a very derived pectoral girdle that is closely comparable to those of derived therians. Given the basal position of this taxon in mammalian phylogeny, its derived pectoral girdle indicates that homoplasies (similarities resulting from independent evolution among unrelated lineages) are as common in the postcranial skeleton as they are in the skull and dentition in the evolution of Mesozoic mammals. Limb structures of the new triconodont indicate that it was probably a ground-dwelling animal.

  12. Membrane skeleton orchestrates the platelet glycoprotein (GP) Ib-IX complex clustering and signaling.

    PubMed

    Shang, Dan; Zhang, Zuping; Wang, Qian; Ran, Yali; Shaw, Tanner S; Van, John N; Peng, Yuandong

    2016-10-01

    Platelet glycoprotein Ib-IX complex is affixed to the membrane skeleton through interaction with actin binding protein 280 (ABP-280). We find that removal of the ABP-280 binding sites in GP Ibα cytoplasmic tail has little impact on the complex clustering induced by antibody crosslinking. However, large truncation of the GP Ibα cytoplasmic tail allows the formation of larger patches of the complex, suggesting that an ABP-280 independent force may exist. Besides, we observe that the signaling upon GP Ib-IX clustering is elicited in both membrane lipid domain dependent and independent manner, a choice that relies on how the membrane skeleton interacts with the complex. Our findings suggest a more complex mechanism for how the membrane skeleton regulates the GP Ib-IX function. © 2016 IUBMB Life, 68(10):823-829, 2016.

  13. Point-process principal components analysis via geometric optimization.

    PubMed

    Solo, Victor; Pasha, Syed Ahmed

    2013-01-01

    There has been a fast-growing demand for analysis tools for multivariate point-process data driven by work in neural coding and, more recently, high-frequency finance. Here we develop a true or exact (as opposed to one based on time binning) principal components analysis for preliminary processing of multivariate point processes. We provide a maximum likelihood estimator, an algorithm for maximization involving steepest ascent on two Stiefel manifolds, and novel constrained asymptotic analysis. The method is illustrated with a simulation and compared with a binning approach. PMID:23020106

  14. Point-process principal components analysis via geometric optimization.

    PubMed

    Solo, Victor; Pasha, Syed Ahmed

    2013-01-01

    There has been a fast-growing demand for analysis tools for multivariate point-process data driven by work in neural coding and, more recently, high-frequency finance. Here we develop a true or exact (as opposed to one based on time binning) principal components analysis for preliminary processing of multivariate point processes. We provide a maximum likelihood estimator, an algorithm for maximization involving steepest ascent on two Stiefel manifolds, and novel constrained asymptotic analysis. The method is illustrated with a simulation and compared with a binning approach.

  15. Weighted EMPCA: Weighted Expectation Maximization Principal Component Analysis

    NASA Astrophysics Data System (ADS)

    Bailey, Stephen

    2016-09-01

    Weighted EMPCA performs principal component analysis (PCA) on noisy datasets with missing values. Estimates of the measurement error are used to weight the input data such that the resulting eigenvectors, when compared to classic PCA, are more sensitive to the true underlying signal variations rather than being pulled by heteroskedastic measurement noise. Missing data are simply limiting cases of weight = 0. The underlying algorithm is a noise weighted expectation maximization (EM) PCA, which has additional benefits of implementation speed and flexibility for smoothing eigenvectors to reduce the noise contribution.

  16. Efficient training of multilayer perceptrons using principal component analysis

    SciTech Connect

    Bunzmann, Christoph; Urbanczik, Robert; Biehl, Michael

    2005-08-01

    A training algorithm for multilayer perceptrons is discussed and studied in detail, which relates to the technique of principal component analysis. The latter is performed with respect to a correlation matrix computed from the example inputs and their target outputs. Typical properties of the training procedure are investigated by means of a statistical physics analysis in models of learning regression and classification tasks. We demonstrate that the procedure requires by far fewer examples for good generalization than traditional online training. For networks with a large number of hidden units we derive the training prescription which achieves, within our model, the optimal generalization behavior.

  17. Isotope and trace element proxies in sclerosponge skeletons: reproducibility and alteration through sampling

    NASA Astrophysics Data System (ADS)

    Kuhlmann, K.; Haase-Schramm, A.; Böhm, F.; Eisenhauer, A.; Joachimski, M. M.; Dullo, W.-C.

    2003-04-01

    During the last decade sclerosponge skeletons have been increasingly used as proxy recorders, e.g. for reconstructions of mixed layer temperature histories, variations of the carbon isotopic composition of seawater or trace metal input to the oceans. We investigated the influences of drilling and bleaching on the reproducibility of the most commonly used proxies in the skeletons of Ceratoporella nicholsoni: δ13C, δ18O and Sr/Ca ratios. We further compare proxy records from different specimens that were correlated by U-Th dating. We find a good reproducibility for δ13C and Sr/Ca ratios. On the other hand, δ18O records show no reproducible trends and do not correlate with the Sr/Ca records. Bleaching alters the isotopic composition of the samples and decreases the reproducibilty. Sr/Ca ratios are not affected by bleaching. XRD analysis shows that fast sample drilling in the dense aragonitic skeletons can produce up to about 1 percent of calcite. Isotope values from samples drilled with different drill speeds show no significant variation, even at elevated calcite contents. Analysis of the organic carbon content shows a 3 cm wide zone in the youngest part of the skeletons with slightly elevated values (0.25 percent). In the older skeletal parts organic carbon contents are lower (0.1 percent). X-ray radiographs show no porosity change with increasing age of the skeleton except for a thin (<5 mm) rim with higher porosities below the oral surface. Overall, porosities are very low (<4 percent). These observations largely exclude early diagenetic influences through secondary cementation or contamination by organic carbon phases. We conclude that the skeletons of C. nicholsoni are very well suited as recorder of environmental proxies like Sr/Ca and δ13C.

  18. Mechanically Viscoelastic Properties of Cellulose Nanocrystals Skeleton Reinforced Hierarchical Composite Hydrogels.

    PubMed

    Yang, Jun; Han, ChunRui

    2016-09-28

    With inspiration from the concept of natural dynamic materials, binary-component composite hydrogels with excellent mechanical properties and recovery capability were prepared from the cellulose nanocrystal (CNC) skeleton reinforced covalently cross-linked polyacrylamide (PAAm) networks. The hierarchical skeleton obtained by freeze-drying of CNC aqueous suspension was directly impregnated into acrylamide (AAm) monomer solution, and in situ polymerization occurred in the presence of hydrophilic cross-linker PEGDA575. Under stress, hydrogen bonds at the interface between CNC and PAAm as well as inside the CNC skeleton acted as sacrificial bonds to dissipate energy, while the covalently cross-linked PAAm chains bind the network together by providing adhesion to CNC and thereby suppress the catastrophic craze propagation. The above synergistic effects of the CNC skeleton and the elastic PAAm network enabled the composite hydrogels to withstand up to 181 kPa of tensile stress, 1.01 MPa of compressive strength, and 1392% elongation at break with the fracture energy as high as 2.82 kJ/m(2). Moreover, the hydrogels recovered more than 70% elasticity after eight loading-unloading cycles, revealing excellent fatigue resistance. The depth-sensing instrumentation by indentation test corroborated that the CNC skeleton contributed simultaneous improvements in hardness and elasticity by as much as 500% in comparison with the properties of the pristine PAAm hydrogels. This elegant strategy by using the CNC skeleton as a reinforcing template offers a new perspective for the fabrication of robust hydrogels with exceptional mechanical properties that may be important for biomedical applications where high strength is required, such as scaffolds for tissue engineering.

  19. Partial skeleton of Theropithecus brumpti (Primates, Cercopithecidae) from the Chemeron Formation of the Tugen Hills, Kenya.

    PubMed

    Gilbert, Christopher C; Goble, Emily D; Kingston, John D; Hill, Andrew

    2011-10-01

    Here we describe a complete skull and partial skeleton of a large cercopithecoid monkey (KNM-TH 46700) discovered in the Chemeron Formation of the Tugen Hills at BPRP Site #152 (2.63 Ma). Associated with the skeleton was a mandible of an infant cercopithecoid (KNM-TH 48364), also described here. KNM-TH 46700 represents an aged adult female of Theropithecus brumpti, a successful Pliocene papionin taxon better known from the Omo Shungura Formation in Ethiopia and sites east and west of Lake Turkana, Kenya. While the morphology of male T. brumpti is well-documented, including a partial skeleton with both cranial and postcranial material, the female T. brumpti morphotype is not well-known. This skeleton represents some of the first associated evidence of cranial and postcranial female T. brumpti remains. In addition to the complete skull, postcranial material includes elements of the axial skeleton and lower limb. While aspects of the skeleton conform to those of specimens previously assigned to T. brumpti, other features on the femur and tibia appear to differ from those previously described for this species. It is unclear whether these differences represent general variation within the T. brumpti population, variation between the sexes in T. brumpti, or the incorrect assignment of previous isolated hindlimb specimens. In total, the observable morphological features of the hindlimb suggest that KNM-TH 46700 was a terrestrial quadruped similar to modern savannah baboons (Papio). From the available evidence, it is difficult to assess whether or not KNM-TH 46700 frequently engaged in the specialized squatting and shuffling behavior observed in extant geladas (Theropithecus gelada).

  20. Mechanically Viscoelastic Properties of Cellulose Nanocrystals Skeleton Reinforced Hierarchical Composite Hydrogels.

    PubMed

    Yang, Jun; Han, ChunRui

    2016-09-28

    With inspiration from the concept of natural dynamic materials, binary-component composite hydrogels with excellent mechanical properties and recovery capability were prepared from the cellulose nanocrystal (CNC) skeleton reinforced covalently cross-linked polyacrylamide (PAAm) networks. The hierarchical skeleton obtained by freeze-drying of CNC aqueous suspension was directly impregnated into acrylamide (AAm) monomer solution, and in situ polymerization occurred in the presence of hydrophilic cross-linker PEGDA575. Under stress, hydrogen bonds at the interface between CNC and PAAm as well as inside the CNC skeleton acted as sacrificial bonds to dissipate energy, while the covalently cross-linked PAAm chains bind the network together by providing adhesion to CNC and thereby suppress the catastrophic craze propagation. The above synergistic effects of the CNC skeleton and the elastic PAAm network enabled the composite hydrogels to withstand up to 181 kPa of tensile stress, 1.01 MPa of compressive strength, and 1392% elongation at break with the fracture energy as high as 2.82 kJ/m(2). Moreover, the hydrogels recovered more than 70% elasticity after eight loading-unloading cycles, revealing excellent fatigue resistance. The depth-sensing instrumentation by indentation test corroborated that the CNC skeleton contributed simultaneous improvements in hardness and elasticity by as much as 500% in comparison with the properties of the pristine PAAm hydrogels. This elegant strategy by using the CNC skeleton as a reinforcing template offers a new perspective for the fabrication of robust hydrogels with exceptional mechanical properties that may be important for biomedical applications where high strength is required, such as scaffolds for tissue engineering. PMID:27606621

  1. Testing block subdivision algorithms on block designs

    NASA Astrophysics Data System (ADS)

    Wiseman, Natalie; Patterson, Zachary

    2016-01-01

    Integrated land use-transportation models predict future transportation demand taking into account how households and firms arrange themselves partly as a function of the transportation system. Recent integrated models require parcels as inputs and produce household and employment predictions at the parcel scale. Block subdivision algorithms automatically generate parcel patterns within blocks. Evaluating block subdivision algorithms is done by way of generating parcels and comparing them to those in a parcel database. Three block subdivision algorithms are evaluated on how closely they reproduce parcels of different block types found in a parcel database from Montreal, Canada. While the authors who developed each of the algorithms have evaluated them, they have used their own metrics and block types to evaluate their own algorithms. This makes it difficult to compare their strengths and weaknesses. The contribution of this paper is in resolving this difficulty with the aim of finding a better algorithm suited to subdividing each block type. The proposed hypothesis is that given the different approaches that block subdivision algorithms take, it's likely that different algorithms are better adapted to subdividing different block types. To test this, a standardized block type classification is used that consists of mutually exclusive and comprehensive categories. A statistical method is used for finding a better algorithm and the probability it will perform well for a given block type. Results suggest the oriented bounding box algorithm performs better for warped non-uniform sites, as well as gridiron and fragmented uniform sites. It also produces more similar parcel areas and widths. The Generalized Parcel Divider 1 algorithm performs better for gridiron non-uniform sites. The Straight Skeleton algorithm performs better for loop and lollipop networks as well as fragmented non-uniform and warped uniform sites. It also produces more similar parcel shapes and patterns.

  2. Wavelet decomposition based principal component analysis for face recognition using MATLAB

    NASA Astrophysics Data System (ADS)

    Sharma, Mahesh Kumar; Sharma, Shashikant; Leeprechanon, Nopbhorn; Ranjan, Aashish

    2016-03-01

    For the realization of face recognition systems in the static as well as in the real time frame, algorithms such as principal component analysis, independent component analysis, linear discriminate analysis, neural networks and genetic algorithms are used for decades. This paper discusses an approach which is a wavelet decomposition based principal component analysis for face recognition. Principal component analysis is chosen over other algorithms due to its relative simplicity, efficiency, and robustness features. The term face recognition stands for identifying a person from his facial gestures and having resemblance with factor analysis in some sense, i.e. extraction of the principal component of an image. Principal component analysis is subjected to some drawbacks, mainly the poor discriminatory power and the large computational load in finding eigenvectors, in particular. These drawbacks can be greatly reduced by combining both wavelet transform decomposition for feature extraction and principal component analysis for pattern representation and classification together, by analyzing the facial gestures into space and time domain, where, frequency and time are used interchangeably. From the experimental results, it is envisaged that this face recognition method has made a significant percentage improvement in recognition rate as well as having a better computational efficiency.

  3. Mediation of muscular control of rhinarial motility in rats by the nasal cartilaginous skeleton

    PubMed Central

    Haidarliu, Sebastian; Kleinfeld, David; Ahissar, Ehud

    2014-01-01

    The Rhinarium is the rostral-most area of the snout that surrounds the nostrils, and is hairless in most mammals. In rodents, it participates in coordinated behaviors, active tactile sensing, and active olfactory sensing. In rats, the Rhinarium is firmly connected to the nasal cartilages, and its motility is determined by movements of the rostral end of the nasal cartilaginous skeleton. Here we demonstrate the nature of different cartilaginous regions that form the Rhinarium and the nasofacial muscles that deform these regions during movements of the nasal cartilaginous skeleton. These muscles, together with the dorsal nasal cartilage that was described here, function as a rhinarial motor plant. PMID:24249396

  4. Meroterpenoids with New Skeletons from Myrtus communis and Structure Revision of Myrtucommulone K.

    PubMed

    Liu, Chao; Ang, Song; Huang, Xiao-Jun; Tian, Hai-Yan; Deng, Yuan-Yuan; Zhang, Dong-Mei; Wang, Ying; Ye, Wen-Cai; Wang, Lei

    2016-08-19

    Five sesquiterpene-based meroterpenoids with three kinds of new skeletons [1, 2, 3, (+)-4, and (-)-4] were isolated from the leaves of Myrtus communis. Compound 1 featured a new carbon skeleton with an unprecedented octahydrospiro[bicyclo[7.2.0]undecane-2,2'-chromene] tetracyclic ring system, which possessed two preferred conformations detected by variable-temperature NMR spectroscopy experiments. In addition, the structure of reported myrtucommulone K was revised to be compound 3. The plausible biosynthetic pathways of these meroterpenoids and their cytotoxicities are discussed. PMID:27471772

  5. Characterization of cultural remains associated to a human skeleton found at the site HMS Swift (1770)

    NASA Astrophysics Data System (ADS)

    Maier, M. S.; Gómez, B. A.; Parera, S. D.; Elkin, D.; De Rosa, H.; Ciarlo, N. C.; Svoboda, H.

    2010-08-01

    Different types of materials found in association with a human skeleton found in an 18th century shipwreck in Patagonia (Argentina) were analyzed by means of OM, SEM-EDX, HPLC, and chemical analysis. Alizarin and purpurin, the main anthraquinones of the dye plant Rubia tinctorum L. (madder) were identified as the coloring matter of a red fabric attached to the skeleton. Metallographic and chemical analysis of one of the dome-shaped buttons associated to the human bones revealed that it was composed of a Pb-Sn-Cu alloy known as pewter. The results obtained support the hypothesis that the remains originally were part of a private marine uniform.

  6. Isolation and identification of chitin in three-dimensional skeleton of Aplysina fistularis marine sponge.

    PubMed

    Wysokowski, Marcin; Bazhenov, Vasilii V; Tsurkan, Mikhail V; Galli, Roberta; Stelling, Allison L; Stöcker, Hartmut; Kaiser, Sabine; Niederschlag, Elke; Gärtner, Günter; Behm, Thomas; Ilan, Micha; Petrenko, Alexander Y; Jesionowski, Teofil; Ehrlich, Hermann

    2013-11-01

    The recent discovery of chitin within skeletons of numerous marine and freshwater sponges (Porifera) stimulates further experiments to identify this structural aminopolysaccharide in new species of these aquatical animals. Aplysina fistularis (Verongida: Demospongiae: Porifera) is well known to produce biologically active bromotyrosines. Here, we present a detailed study of the structural and physico-chemical properties of the three-dimensional skeletal scaffolds of this sponge. Calcofluor white staining, Raman and IR spectroscopy, ESI-MS as well as chitinase digestion test were applied in order to unequivocally prove the first discovery of α-chitin in skeleton of A. fistularis.

  7. Simulating certain aspects of hypogravity - Effects on bone maturation in the nonweight bearing skeleton

    NASA Technical Reports Server (NTRS)

    Simmons, D. J.; Grazman, B.; Russell, J. E.; Walker, W. V.; Bikle, D. D.; Morey, E. R.

    1983-01-01

    For a determination of how the nonweight-bearing skeletons, i.e., lower jaws, of 41-day and 1-year old rats would respond to 10 or 14 days of partial skeletal unloading by elevating the hindquarters (PULEH), an experimental system to simulate the fluid shifts and unloading of portions of the skeleton which occur during spaceflight was developed. In comparison with the bone matrix mineralization recorded in the mandibles of rats flown in the Soviet 18.5 day Cosmos-1129 mission, the PULEH studies failed to produce spaceflight-like maturation defects.

  8. [Face reconstruction and anthropological skeleton investigation of general Władysław Sikorski].

    PubMed

    Czubak, Andrzej

    2009-01-01

    Anthropological examinations were an integral part of comprehensive postmortem investigations of the person buried as general Władysław Sikorski. Apart from confirming the identity, an inspection and anthropological measurements of the skull and the skeleton were performed. On this basis, the age of the person, his racial type and height were established Moreover, the proportions of the skull were determined, two reconstructions of the appearance of the face were performed by drawing and computer methods and the state of teeth and general condition of the skeleton were described. PMID:19711815

  9. Skeleton-based human action recognition using multiple sequence alignment

    NASA Astrophysics Data System (ADS)

    Ding, Wenwen; Liu, Kai; Cheng, Fei; Zhang, Jin; Li, YunSong

    2015-05-01

    Human action recognition and analysis is an active research topic in computer vision for many years. This paper presents a method to represent human actions based on trajectories consisting of 3D joint positions. This method first decompose action into a sequence of meaningful atomic actions (actionlets), and then label actionlets with English alphabets according to the Davies-Bouldin index value. Therefore, an action can be represented using a sequence of actionlet symbols, which will preserve the temporal order of occurrence of each of the actionlets. Finally, we employ sequence comparison to classify multiple actions through using string matching algorithms (Needleman-Wunsch). The effectiveness of the proposed method is evaluated on datasets captured by commodity depth cameras. Experiments of the proposed method on three challenging 3D action datasets show promising results.

  10. Surface skeleton generation based on 360-degree profile scan

    NASA Astrophysics Data System (ADS)

    Chen, Lujie; Sass, Lawrence; Sung, Woong Ki; Noel, Vernelle

    2013-05-01

    A rapid prototyping method is invented, which works on a specific data structure produced by an optical metrology technique: 360-degree surface profile scanning. A computer algorithm takes an object profile data, restructure the format, generate horizontal and vertical ribs, lay out the ribs on a 2D canvas and output the geometries to a file format compatible with laser cutters. A laser cutting machine is subsequently used to cut all the ribs from sheet materials. Then, the ribs are manually assembled based on computer-generated assembly codes. Through this process, the original object's 3D surface can be prototyped rapidly at an arbitrary scale, which may well exceed the working dimension of the laser cutter.

  11. The Endocrine Role of Estrogens on Human Male Skeleton

    PubMed Central

    Rochira, Vincenzo; Kara, Elda; Carani, Cesare

    2015-01-01

    Before the characterization of human and animal models of estrogen deficiency, estrogen action was confined in the context of the female bone. These interesting models uncovered a wide spectrum of unexpected estrogen actions on bone in males, allowing the formulation of an estrogen-centric theory useful to explain how sex steroids act on bone in men. Most of the principal physiological events that take place in the developing and mature male bone are now considered to be under the control of estrogen. Estrogen determines the acceleration of bone elongation at puberty, epiphyseal closure, harmonic skeletal proportions, the achievement of peak bone mass, and the maintenance of bone mass. Furthermore, it seems to crosstalk with androgen even in the determination of bone size, a more androgen-dependent phenomenon. At puberty, epiphyseal closure and growth arrest occur when a critical number of estrogens is reached. The same mechanism based on a critical threshold of serum estradiol seems to operate in men during adulthood for bone mass maintenance via the modulation of bone formation and resorption in men. This threshold should be better identified in-between the ranges of 15 and 25 pg/mL. Future basic and clinical research will optimize strategies for the management of bone diseases related to estrogen deficiency in men. PMID:25873947

  12. Parallel transport on principal bundles over stacks

    NASA Astrophysics Data System (ADS)

    Collier, Brian; Lerman, Eugene; Wolbert, Seth

    2016-09-01

    In this paper we introduce a notion of parallel transport for principal bundles with connections over differentiable stacks. We show that principal bundles with connections over stacks can be recovered from their parallel transport thereby extending the results of Barrett, Caetano and Picken, and Schreiber and Waldorf from manifolds to stacks. In the process of proving our main result we simplify Schreiber and Waldorf's original definition of a transport functor for principal bundles with connections over manifolds and provide a more direct proof of the correspondence between principal bundles with connections and transport functors.

  13. Understanding the Principal's Contribution to Instruction: Seven Principals, Seven Stories. Case #5: Jonathan Rolf, Principal of a Suburban Elementary School.

    ERIC Educational Resources Information Center

    Dwyer, David C.; And Others

    This case study presents findings from a year-long ethnographic study of a suburban elementary school principal. It concludes one of seven studies conducted in elementary and intermediate schools in urban, suburban, and rural settings to investigate the instructional management role of principals. Although previous research offers disparate…

  14. Instructional or Managerial Leadership: The Principal Role!

    ERIC Educational Resources Information Center

    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…

  15. Principal Vacancies and Appointments 2009-10

    ERIC Educational Resources Information Center

    Robertson, Sally

    2011-01-01

    School leadership in New Zealand has gained more attention in recent years. The New Zealand Council for Educational Research (NZCER) began collecting data on all principal advertisements in the "Education Gazette" in late 2007. This brief report analyses principal vacancies advertised in the "Education Gazette" in 2009 and 2010. It also analyses…

  16. Artful Dodges Principals Use to Beat Bureaucracy.

    ERIC Educational Resources Information Center

    Ficklen, Ellen

    1982-01-01

    A study of Chicago (Illinois) principals revealed many ways principals practiced "creative insubordination"--avoiding following instructions but still getting things done. Among the dodges are deliberately missing deadlines, following orders literally, ignoring channels to procure teachers or materials, and using community members to communicate…

  17. Superintendents' Perceptions of the Principal Shortage

    ERIC Educational Resources Information Center

    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…

  18. Year-Round Education: Florida Principals' Perspectives.

    ERIC Educational Resources Information Center

    Pawlas, George E.

    1996-01-01

    Summarizes a survey focused on the job satisfaction/burnout of 97 Florida principals heading year-round schools. Principals most enjoyed school-improvement initiatives, contacts with students, and staff development activities. Major stressors included problems with personnel and parents, heavier workload, scheduling problems, lack of "down time,"…

  19. The Daily Practices of Successful Principals

    ERIC Educational Resources Information Center

    Brock, Barbara L.; Grady, Marilyn L.

    2011-01-01

    While many books outline the attributes of successful school leaders, few describe how those traits manifest in daily practice. "The Daily Practices of Successful Principals" goes beyond the outward picture of excellence and provides a compendium of daily practices used by successful principals in various settings. Written by former administrators…

  20. Social Media Strategies for School Principals

    ERIC Educational Resources Information Center

    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.…

  1. The New Principal's Fieldbook: Strategies for Success

    ERIC Educational Resources Information Center

    Robbins, Pam; Alvy, Harvey

    2004-01-01

    Any principal starting at a new school or taking a leadership position for the first time needs this book to help focus on the issues that are most critical to success. Drawing from research data and advice from experienced principals, the authors reveal secrets that can make or break a new school leader's career: (1) Three stages of becoming…

  2. Multidimensional Perspectives on Principal Leadership Effectiveness

    ERIC Educational Resources Information Center

    Beycioglu, Kadir, Ed.; Pashiardis, Petros, Ed.

    2015-01-01

    Exceptional management skills are crucial to success in educational environments. As school leaders, principals are expected to effectively supervise the school system while facing a multitude of issues and demands. "Multidimensional Perspectives on Principal Leadership Effectiveness" combines best practices and the latest approaches in…

  3. A Perspective on Women Principals in Turkey

    ERIC Educational Resources Information Center

    Celikten, Mustafa

    2005-01-01

    This article explores the reasons why there are a relatively small number of women principals in Turkish state elementary schools. Current literature on women principals reveals that while many professional fields are showing increasing numbers of women in managerial and executive positions, the same cannot be said for educational administration.…

  4. A Principal's Guide to Reading Recovery.

    ERIC Educational Resources Information Center

    Smith-Burke, M. Trika; Pinnell, Gay Su; Jackson, Mary; Wey, Susan; Askew, Billie J.; Hambright-Brown, Eloise

    This guide, requested by principals across the nation, is intended to help them successfully implement Reading Recovery in their schools. The guide is organized by topics that experienced principals have said are important to ongoing program operation. To help access information quickly, a detailed table of contents is provided, as well as an…

  5. The Fairfax County (Va.) Principals' Research Group.

    ERIC Educational Resources Information Center

    Endo, Todd

    1987-01-01

    Describes the activities developed for the "Students with Special Needs" group of the Fairfax County Principals' Research Group. The "Research Group" has shown that principals can implement ideas that do not emerge from any other source in the school system. (MD)

  6. Principal Prep for Common Core Gaining Traction

    ERIC Educational Resources Information Center

    Gewertz, Catherine

    2012-01-01

    A year ago, top officials in the school leadership world were worried. It seemed to them that principals were being overlooked in national conversations about how to get educators ready for the Common Core State Standards. But that is changing. The past six months have seen a surge of activity to acquaint principals with the new standards and…

  7. Contextual Factors Related to Elementary Principal Turnover

    ERIC Educational Resources Information Center

    Partlow, Michelle C.

    2007-01-01

    The issue of school leadership instability and how it affects schools and student achievement has been studied. The question of how to predict turnover of the principal remains an unknown. The purpose of this research was to search for possible relationships between certain contextual variables and principal turnover and to test the independent…

  8. Principals as Partners: Counselors as Collaborators

    ERIC Educational Resources Information Center

    Dahir, Carol A.; Burnham, Joy J.; Stone, Carolyn B.; Cobb, Nicole

    2010-01-01

    School principals and school counselors have the ability to forge a unique collaborative relationship to improve student achievement. Historically, school counselors have altered the primary focus of their work as deemed by the perspective of their principals. With an emphasis on improving student success in school, this study revealed the…

  9. The Principal and the Issue of Negligence.

    ERIC Educational Resources Information Center

    Permuth, Steve

    1998-01-01

    Individuals wishing to establish a legal negligence claim against a principal must first present evidence of recognizable duty (adequate supervision); breach of duty; proximate cause; and injury. Wise principals schedule periodic meetings to review safety measures, focus on vulnerable areas, designate an emergency stand-in, review equipment and…

  10. Instructional Leadership: Are Women Principals Better?

    ERIC Educational Resources Information Center

    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…

  11. Estimating Principal Effectiveness. Working Paper 32

    ERIC Educational Resources Information Center

    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…

  12. Perceptions of Online Credentials for School Principals

    ERIC Educational Resources Information Center

    Richardson, Jayson W.; McLeod, Scott; Dikkers, Amy Garrett

    2011-01-01

    Purpose: The purpose of this study is to investigate the perceptions of human resource directors in the USA about online credentials earned by K-12 school principals and principal candidates. Design/methodology/approach: In this mixed methods study, a survey was sent to a random sample of 500 human resource directors in K-12 school districts…

  13. Effectiveness of Principals as Evaluators of Teachers

    ERIC Educational Resources Information Center

    Gregoire, Shirley Ann

    2009-01-01

    The purpose of this study was to gather perceptions of principals and teachers with regard to the effectiveness of principals as evaluators of teachers. Perceptions were reviewed within the context of seven standards across the four attributes of the personnel standards developed by the Joint Committee on Standards for Educational Evaluation…

  14. Learning to Lead: Ten Stories for Principals

    ERIC Educational Resources Information Center

    Chirichello, Michael; Richmond, Nancy

    2006-01-01

    Principals must be knowledgeable about students, curriculum, teacher performance, and the community that they serve while at the same time, able to manage a myriad of daily activities. Often times, management activities predominate and take time away from leadership leaving little time for principals to engage in reflective thinking and proactive…

  15. The Role of the Principal in Development.

    ERIC Educational Resources Information Center

    Konzen, Joel M.

    Principals have an essential role in school development that includes an institution's effort to reach its goals and objectives. The main responsibility for development lies in the principal's knowledge, team building, involvement, and volunteer gathering. Setting the stage for development means establishing quality as a comprehensive goal,…

  16. The Learning Principal. Volume 6, Number 1

    ERIC Educational Resources Information Center

    Armstrong, Anthony, Ed.

    2010-01-01

    "The Learning Principal" is an eight-page newsletter published eight times a year. It focuses on the important and unique work of school principals. This issue includes: (1) Taking Action on Equity (Anthony Armstrong); (2) School Leadership: Just How Forward Thinking Are You? (Frederick Brown); (3) From the Research: Leadership Practices that Make…

  17. Principal Preparation--Revisited--Time Matters

    ERIC Educational Resources Information Center

    Gutmore, Daniel

    2015-01-01

    There has been both a historic and continuing interest in the preparation process for school administrators (principals and vice principals). Much of the literature has been critical of how school administrators are prepared (Achilles, 1991; Hale and Moorman, 2003; Levine, 2005; Hallinger and Lu, 2013). Although the length of time from graduation…

  18. Professional Development: Perceptions of Benefits for Principals

    ERIC Educational Resources Information Center

    Blaik Hourani, Rida; Stringer, Patricia

    2015-01-01

    Schools in Abu Dhabi are going through change and reform. Abu Dhabi Education Council (ADEC) has initiated professional development for principals to facilitate change and school improvement. This paper explores principals' perception on the benefits of professional development received in light of managing school change and reforms.…

  19. Bennett Public Schools Principal Induction Program

    ERIC Educational Resources Information Center

    Wilson, Ross; Beaudoin, Colleen; Carmona, Ruben; Delahanty, Michael; Gartside, William; Oyedele, Abidemi; Teta, Lynne Mooney

    2012-01-01

    Ensuring equity in education and academic success for all students requires a highly skilled principal engages others in continually improving the instructional program in order to meet the needs of students. Over the past few years, a number of reports have indicated that the role of principal is becoming more challenging. School districts are…

  20. The Big Rocks: Priority Management for Principals

    ERIC Educational Resources Information Center

    Marshall, Kim

    2008-01-01

    How can a dedicated principal work really, really hard but fail to get significant gains in student achievement? The answer is obvious: by spending too much time on the wrong things and not enough on the right things. The principal's number-one priority is zeroing in on the highest-priority activities for bringing all students to high levels of…

  1. Principals: Human Capital Managers at Every School

    ERIC Educational Resources Information Center

    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…

  2. Principal Turnover. Information Capsule. Volume 0914

    ERIC Educational Resources Information Center

    Blazer, Christie

    2010-01-01

    Recent studies indicate that school districts are facing increasing rates of principal turnover. Frequent principal changes deprive schools of the leadership stability they need to succeed, disrupt long-term school reform efforts, and may even be linked to increased teacher turnover and lower levels of student achievement. This Information Capsule…

  3. School Principal Speech about Fiscal Mismanagement

    ERIC Educational Resources Information Center

    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.

  4. Attitudes of Principals About Early Childhood Teachers.

    ERIC Educational Resources Information Center

    Seifert, Kelvin; Lyons, Wendy

    In this study researchers wanted to discover school principals' attitudes about reported increases in the proportion of men teaching very young children. Elementary school principals in southern Manitoba were interviewed about their attitudes toward beginning teachers in early childhood (nursery-kindergarten) education. At the time of writing,…

  5. A Latina Principal Leading for Social Justice

    ERIC Educational Resources Information Center

    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…

  6. Principals' Perceptions of School Public Relations

    ERIC Educational Resources Information Center

    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…

  7. Revising the Role of Principal Supervisor

    ERIC Educational Resources Information Center

    Saltzman, Amy

    2016-01-01

    In Washington, D.C., and Tulsa, Okla., districts whose efforts are supported by the Wallace Foundation, principal supervisors concentrate on bolstering their principals' work to improve instruction, as opposed to focusing on the managerial or operational aspects of running a school. Supervisors oversee fewer schools, which enables them to provide…

  8. Micropolitics: Empowering Principals to Accomplish Goals.

    ERIC Educational Resources Information Center

    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…

  9. Exploring Principals' Perceptions of Supervised Agricultural Experience

    ERIC Educational Resources Information Center

    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,…

  10. 47 CFR 76.1607 - Principal headend.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Principal headend. 76.1607 Section 76.1607 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Notices § 76.1607 Principal headend. A cable operator shall provide...

  11. 47 CFR 76.1607 - Principal headend.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Principal headend. 76.1607 Section 76.1607 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Notices § 76.1607 Principal headend. A cable operator shall provide...

  12. 47 CFR 76.1607 - Principal headend.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Principal headend. 76.1607 Section 76.1607 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Notices § 76.1607 Principal headend. A cable operator shall provide...

  13. 47 CFR 76.1607 - Principal headend.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Principal headend. 76.1607 Section 76.1607 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Notices § 76.1607 Principal headend. A cable operator shall provide...

  14. 47 CFR 76.1607 - Principal headend.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Principal headend. 76.1607 Section 76.1607 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES MULTICHANNEL VIDEO AND CABLE TELEVISION SERVICE Notices § 76.1607 Principal headend. A cable operator shall provide...

  15. New Principals: Problems, Priorities, and Preparation.

    ERIC Educational Resources Information Center

    Osterman, Karen F.; And Others

    Findings of the first phase of a longitudinal study that developed a descriptive profile of new principals in New York City are presented in this paper. A survey of 216 newly appointed principals in New York City elicited 158 responses, a 73 percent response rate. Findings indicate that despite the emphasis on aspects of transformational…

  16. Elementary Principals' Role in Science Instruction

    ERIC Educational Resources Information Center

    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…

  17. Nonlinear Principal Components Analysis: Introduction and Application

    ERIC Educational Resources Information Center

    Linting, Marielle; Meulman, Jacqueline J.; Groenen, Patrick J. F.; van der Koojj, Anita J.

    2007-01-01

    The authors provide a didactic treatment of nonlinear (categorical) principal components analysis (PCA). This method is the nonlinear equivalent of standard PCA and reduces the observed variables to a number of uncorrelated principal components. The most important advantages of nonlinear over linear PCA are that it incorporates nominal and ordinal…

  18. Capital Wisdom: Papers from the Principals Academy.

    ERIC Educational Resources Information Center

    Walsh, Anne, Ed.; Feistritzer, Patricia, Ed.

    During the 1991 National Catholic Principals Academy, 30 elementary school principals came together to sharpen their skills, to be exposed to new trends and ideas, and to be empowered as Catholic education administrators. This handbook is the result of sharing ideas and is a compilation of tried and true processes, "how to" advice, and practical…

  19. An Examination of Principal Job Satisfaction

    ERIC Educational Resources Information Center

    Pengilly, Michelle M.

    2010-01-01

    As education continues to succumb to deficits in budgets and increasingly high levels of student performance to meet the federal and state mandates, the quest to sustain and retain successful principals is imperative. The National Association of School Boards (1999) portrays effective principals as "linchpins" of school improvement and the…

  20. Should Principals Know More about Law?

    ERIC Educational Resources Information Center

    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.

  1. Handheld Computers: A Boon for Principals

    ERIC Educational Resources Information Center

    Brazell, Wayne

    2005-01-01

    As I reflect on my many years as an elementary school principal, I realize how much more effective I would have been if I had owned a wireless handheld computer. This relatively new technology can provide considerable assistance to today?s principals and recent advancements have increased its functions and capacity. Handheld computers are…

  2. Career Paths of Female Elementary Assistant Principals

    ERIC Educational Resources Information Center

    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…

  3. Integrating Technology: The Principals' Role and Effect

    ERIC Educational Resources Information Center

    Machado, Lucas J.; Chung, Chia-Jung

    2015-01-01

    There are many factors that influence technology integration in the classroom such as teacher willingness, availability of hardware, and professional development of staff. Taking into account these elements, this paper describes research on technology integration with a focus on principals' attitudes. The role of the principal in classroom…

  4. Effective Principals: Knowledge, Talent, Spirit of Inquiry.

    ERIC Educational Resources Information Center

    Murphy, Carol

    1983-01-01

    To explore the principal's role as instructional leader in school improvement strategies, this research brief focuses on characteristics of effective schools, a profile of effective principals, and a discussion with Dr. Steven Bossert, Associate Laboratory Director for Research and Development at Far West Laboratory in San Francisco, California,…

  5. Assistant Principals and Reform: A Socialization Paradox?

    ERIC Educational Resources Information Center

    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…

  6. Principal, Finesse Your Way to Instructional Leadership.

    ERIC Educational Resources Information Center

    Hutto, James R.; Criss, Gail D.

    1993-01-01

    Effective principals pay close attention to body language and other subtle actions that are constantly read and interpreted by staff and students. Principals must not only talk the talk of an instructional leader but also walk the walk of a committed instructional leader. Specific suggestions are provided. (MLH)

  7. Enchondroma versus Chondrosarcoma in Long Bones of Appendicular Skeleton: Clinical and Radiological Criteria—A Follow-Up

    PubMed Central

    Ferrer-Santacreu, Eugenio M.; Ortiz-Cruz, Eduardo J.; Díaz-Almirón, Mariana; Pozo Kreilinger, Jose Juan

    2016-01-01

    As of today two types of cartilage tumors remain a challenge even for the orthopedic oncologist: enchondroma (E), a benign tumor, and chondrosarcoma (LGC), a malignant and low aggressiveness tumor. A prospective study of 133 patients with a cartilaginous tumor of low aggressiveness in the long bones of the appendicular skeleton was done to prove this difficult differential diagnosis. Parameters including medical history and radiological and nuclear imaging were collected and compared to the result of the biopsy. A scale of aggressiveness was applied to each patient according to the number of aggressiveness episodes present. A comparison of the results of the biopsy with the initial diagnosis made by the orthopedic oncologist based solely on clinical data and imaging tests was also made. Finally, a management algorithm for these cases was proposed. A statistical significance for LGC resulted from the parameter as follows: pain on palpation, involvement of cortical in either the CT or MRI, and Tc99 bone scan uptake equal or superior to anterosuperior iliac crest. In our series, a tumor scoring 5 points or higher in the scale of aggressiveness can have 50% more chance of being LGC. When compared with the gold standard (the biopsy), surgeon's initial judgement showed a sensitivity of 73.5% and a specificity of 94.1%. PMID:27034667

  8. Heterochronic activation of VEGF signaling and the evolution of the skeleton in echinoderm pluteus larvae.

    PubMed

    Morino, Yoshiaki; Koga, Hiroyuki; Tachibana, Kazunori; Shoguchi, Eiichi; Kiyomoto, Masato; Wada, Hiroshi

    2012-01-01

    The evolution of the echinoderm larval skeleton was examined from the aspect of interactions between skeletogenic mesenchyme cells and surrounding epithelium. We focused on vascular endothelial growth factor (VEGF) signaling, which was reported to be essential for skeletogenesis in sea urchin larvae. Here, we examined the expression patterns of vegf and vegfr in starfish and brittle stars. During starfish embryogenesis, no expression of either vegfr or vegf was detected, which contrast with previous reports on the expression of starfish homologs of sea urchin skeletogenic genes, including Ets, Tbr, and Dri. In later stages, when adult skeletogenesis commenced, vegfr and vegf expression were upregulated in skeletogenic cells and in the adjacent epidermis, respectively. These expression patterns suggest that heterochronic activation of VEGF signaling is one of the key molecular evolutionary steps in the evolution of the larval skeleton. The absence of vegf or vegfr expression during early embryogenesis in starfish suggests that the evolution of the larval skeleton requires distinct evolutionary changes, both in mesoderm cells (activation of vegfr expression) and in epidermal cells (activation of vegf expression). In brittle stars, which have well-organized skeletons like the sea urchin, vegfr and vegf were expressed in the skeletogenic mesenchyme and the overlying epidermis, respectively, in the same manner as in sea urchins. Therefore, the distinct activation of vegfr and vegf may have occurred in two lineages, sea urchins and brittle stars.

  9. Mineral homeostasis and regulation of mineralization processes in the skeletons of sharks, rays and relatives (Elasmobranchii).

    PubMed

    Dean, Mason N; Ekstrom, Laura; Monsonego-Ornan, Efrat; Ballantyne, Jim; Witten, P Eckhard; Riley, Cyrena; Habraken, Wouter; Omelon, Sidney

    2015-10-01

    Sharks, rays and other elasmobranch fishes are characterized by a skeletal type that is unique among living vertebrates, comprised predominantly of an unmineralized cartilage, covered by a thin outer layer of sub-millimeter, mineralized tiles called tesserae. The mineralized portion of the skeleton appears to grow only by apposition, adding material at the edges of each tessera; maintenance of non-mineralized joints between tesserae is therefore vital, with precise control of mineral deposition and inhibition at the many thousands of growth fronts in the skeleton. Yet, we have only scattered evidence as to how the elasmobranchs mineralize and grow their skeletons. In this review, we take an "environment to skeleton" approach, drawing together research from a vast range of perspectives to track calcium and phosphate from the typical elasmobranch habitats into and through the body, to their deposition at tesseral growth fronts. In the process, we discuss the available evidence for skeletal resorption capability, mineral homeostasis hormones, and nucleation inhibition mechanisms. We also outline relevant theories in crystal nucleation and typical errors in measurements of serum calcium and phosphate in the study of vertebrate biology. We assemble research that suggests consensus in some concepts in elasmobranch skeletal development, but also highlight the very large gaps in our knowledge, particularly in regards to endocrine functional networks and biomineralization mechanisms. In this way, we lay out frameworks for future directions in the study of elasmobranch skeletal biology with stronger and more comparative links to research in other disciplines and into other taxa.

  10. Skeletonization of the internal thoracic artery: a randomized comparison of harvesting methods.

    PubMed

    Urso, Stefano; Alvarez, Luis; Sádaba, Rafael; Greco, Ernesto

    2008-02-01

    We performed a randomized study to compare internal thoracic artery (ITA) flow response to two harvesting methods used in the skeletonization procedure: ultrasonic scalpel and bipolar electrocautery. Sixty patients scheduled for CABG were randomized to receive either ultrasonically (n=30 patients) or electrocautery (n=30 patients) skeletonized ITAs. Intraoperative ITA graft mean flows were obtained with a transit-time flowmeter. ITA flows were evaluated at the beginning (Time 1) and at the end (Time 2) of the harvesting procedure. Post-cardiopulmonary bypass (CPB) flow measurement (Time 3) was obtained in the ITA grafts anastomosed to the left anterior descending artery. Intraoperative mean flow decreased significantly within ultrasonic group (Group U) and electrocautery group (Group E) at the end of the harvesting procedure (P<0.0001 in both cases). Within both groups the final mean flow measured on anastomosed ITAs (Time 3) was significantly higher than the beginning ITA flow value (Time 1). No statistical difference was noted comparing ITA flows between the two groups at any time of evaluation. Skeletonization harvesting of the ITA produces a modification of the mean flow. The quantity and the reversibility of this phenomenon, probably related to vasospasm, are independent from the energy source used in the skeletonization procedure. PMID:17998305

  11. Skeleton photoperiods alter delayed-type hypersensitivity responses and reproductive function of Siberian hamsters (Phodopus sungorus).

    PubMed

    Gatien, M L; Hotchkiss, A K; Dhabhar, F S; Nelson, R J

    2005-11-01

    Photoperiod (day length) can modulate immune function. Whether these photoperiodic effects on immune function are mediated directly by a circadian photoperiodic time measurement system or indirectly by nonspecific (e.g. stressful) effects of light is unknown. To discriminate between these two possibilities, Siberian hamsters (Phodopus sungorus) were housed in either long or short photoperiods (LD 16 : 8 h or LD 8 : 16 h) or in 'skeleton' long or short photoperiods (LD 1 : 14 h: LD 1 : 8 h or LD 1 : 6 h: LD 1 : 16 h). In the skeleton photoperiods, both long- and short-day animals received 2 h of light per day. After 10 weeks in their respective photoperiods, hamsters were tested for an antigen specific immune response using a delayed type hypersensitivity (DTH) model. Reproductive and endocrine responses of hamsters in each of the skeleton photoperiods were equivalent to those in standard long or short days, respectively. Hamsters in skeleton short days and LD 8 : 16 increased DTH responses compared to hamsters in both long-day groups. DTH responses were equivalent in both long-day groups. These results suggest that the influences of day length on immune function potentially are due to circadian photoperiodic time measurement systems.

  12. Multifractal characterization of morphology of human red blood cells membrane skeleton.

    PubMed

    Ţălu, Ş; Stach, S; Kaczmarska, M; Fornal, M; Grodzicki, T; Pohorecki, W; Burda, K

    2016-04-01

    The purpose of this paper is to show applicability of multifractal analysis in investigations of the morphological changes of ultra-structures of red blood cells (RBCs) membrane skeleton measured using atomic force microscopy (AFM). Human RBCs obtained from healthy and hypertensive donors as well as healthy erythrocytes irradiated with neutrons (45 μGy) were studied. The membrane skeleton of the cells was imaged using AFM in a contact mode. Morphological characterization of the three-dimensional RBC surfaces was realized by a multifractal method. The nanometre scale study of human RBCs surface morphology revealed a multifractal geometry. The generalized dimensions Dq and the singularity spectrum f(α) provided quantitative values that characterize the local scale properties of their membrane skeleton organization. Surface characterization was made using areal ISO 25178-2: 2012 topography parameters in combination with AFM topography measurement. The surface structure of human RBCs is complex with hierarchical substructures resulting from the organization of the erythrocyte membrane skeleton. The analysed AFM images confirm a multifractal nature of the surface that could be useful in histology to quantify human RBC architectural changes associated with different disease states. In case of very precise measurements when the red cell surface is not wrinkled even very fine differences can be uncovered as was shown for the erythrocytes treated with a very low dose of ionizing radiation. PMID:27002485

  13. A Skeleton Tells Its Own Story: Forensic Analyses of Skeletal Elements for the Science Classroom Laboratory

    ERIC Educational Resources Information Center

    Naples, Virginia L.; Breed, David; Miller, Jon S.

    2010-01-01

    The techniques of forensic anthropology and pathology can provide new information to increase student interest in studying the structural details of the human skeleton. We present a simplified methodology for assessing skeletal ethnicity, sex, age, and stature. An inexpensive method has been devised for constructing an osteometric board to allow…

  14. Effects of ocean acidification on the dissolution rates of reef-coral skeletons.

    PubMed

    van Woesik, Robert; van Woesik, Kelly; van Woesik, Liana; van Woesik, Sandra

    2013-01-01

    Ocean acidification threatens the foundation of tropical coral reefs. This study investigated three aspects of ocean acidification: (i) the rates at which perforate and imperforate coral-colony skeletons passively dissolve when pH is 7.8, which is predicted to occur globally by 2100, (ii) the rates of passive dissolution of corals with respect to coral-colony surface areas, and (iii) the comparative rates of a vertical reef-growth model, incorporating passive dissolution rates, and predicted sea-level rise. By 2100, when the ocean pH is expected to be 7.8, perforate Montipora coral skeletons will lose on average 15 kg CaCO3 m(-2) y(-1), which is approximately -10.5 mm of vertical reduction of reef framework per year. This rate of passive dissolution is higher than the average rate of reef growth over the last several millennia and suggests that reefs composed of perforate Montipora coral skeletons will have trouble keeping up with sea-level rise under ocean acidification. Reefs composed of primarily imperforate coral skeletons will not likely dissolve as rapidly, but our model shows they will also have trouble keeping up with sea-level rise by 2050. PMID:24282670

  15. Specification to biomineralization: following a single cell type as it constructs a skeleton.

    PubMed

    Lyons, Deirdre C; Martik, Megan L; Saunders, Lindsay R; McClay, David R

    2014-10-01

    The sea urchin larva is shaped by a calcite endoskeleton. That skeleton is built by 64 primary mesenchyme cells (PMCs) in Lytechinus variegatus. The PMCs originate as micromeres due to an unequal fourth cleavage in the embryo. Micromeres are specified in a well-described molecular sequence and enter the blastocoel at a precise time using a classic epithelial-mesenchymal transition. To make the skeleton, the PMCs receive signaling inputs from the overlying ectoderm, which provides positional information as well as control of the growth of initial skeletal tri-radiates. The patterning of the skeleton is the result both of autonomous inputs from PMCs, including production of proteins that are included in the skeletal matrix, and of non-autonomous dynamic information from the ectoderm. Here, we summarize the wealth of information known about how a PMC contributes to the skeletal structure. The larval skeleton is a model for understanding how information encoded in DNA is translated into a three-dimensional crystalline structure.

  16. Skeleton-supported stochastic networks of organic memristive devices: Adaptations and learning

    SciTech Connect

    Erokhina, Svetlana; Sorokin, Vladimir; Erokhin, Victor

    2015-02-15

    Stochastic networks of memristive devices were fabricated using a sponge as a skeleton material. Cyclic voltage-current characteristics, measured on the network, revealed properties, similar to the organic memristive device with deterministic architecture. Application of the external training resulted in the adaptation of the network electrical properties. The system revealed an improved stability with respect to the networks, composed from polymer fibers.

  17. Skeleton-based OPC application for DSA full chip mask correction

    NASA Astrophysics Data System (ADS)

    Schneider, L.; Farys, V.; Serret, E.; Fenouillet-Beranger, C.

    2015-09-01

    Recent industrial results around directed self-assembly (DSA) of block copolymers (BCP) have demonstrated the high potential of this technique [1-2]. The main advantage being cost reduction thanks to a reduced number of lithographic steps. Meanwhile, the associated correction for mask creation must account for the introduction of this new technique, maintaining a high level of accuracy and reliability. In order to create VIA (Vertical Interconnect Layer) layer, graphoepitaxy DSA can be used. The technique relies on the creation of a confinement guides where the BCP can separate into distinct regions and resulting patterns are etched in order to obtain an ordered series of VIA contact. The printing of the guiding pattern requires the use of classical lithography. Optical proximity correction (OPC) is applied to obtain the best suited guiding pattern allowing to match a specific design target. In this study, an original approach for DSA full chip mask optical proximity correction based on a skeleton representation of a guiding pattern is proposed. The cost function for an OPC process is based on minimizing the Central Placement Error (CPE), defined as the difference between an ideal skeleton target and a generated skeleton from a guiding contour. The high performance of this approach for DSA OPC full chip correction and its ability to minimize variability error on via placement is demonstrated and reinforced by the comparison with a rigorous model. Finally this Skeleton approach is highlighted as an appropriate tool for Design rules definition.

  18. What's Inside Bodies? Learning about Skeletons and Other Organ Systems of Vertebrate Animals.

    ERIC Educational Resources Information Center

    Tunnicliffe, Sue Dale; Reiss, Michael

    This paper describes a study of young children's understanding of what is on the inside of animals--skeletons and other organ systems. The study uses 2-D drawings based on the idea that a drawing is the representational model and is the outward expression of the mental model. The 617 drawings made by participants in the study were awarded one of…

  19. Origin and evolution of the integumentary skeleton in non-tetrapod vertebrates

    PubMed Central

    Sire, Jean-Yves; Donoghue, Philip C J; Vickaryous, Matthews K

    2009-01-01

    Most non-tetrapod vertebrates develop mineralized extra-oral elements within the integument. Known collectively as the integumentary skeleton, these elements represent the structurally diverse skin-bound contribution to the dermal skeleton. In this review we begin by summarizing what is known about the histological diversity of the four main groups of integumentary skeletal tissues: hypermineralized (capping) tissues; dentine; plywood-like tissues; and bone. For most modern taxa, the integumentary skeleton has undergone widespread reduction and modification often rendering the homology and relationships of these elements confused and uncertain. Fundamentally, however, all integumentary skeletal elements are derived (alone or in combination) from only two types of cell condensations: odontogenic and osteogenic condensations. We review the origin and diversification of the integumentary skeleton in aquatic non-tetrapods (including stem gnathostomes), focusing on tissues derived from odontogenic (hypermineralized tissues, dentines and elasmodine) and osteogenic (bone tissues) cell condensations. The novelty of our new scenario of integumentary skeletal evolution resides in the demonstration that elasmodine, the main component of elasmoid scales, is odontogenic in origin. Based on available data we propose that elasmodine is a form of lamellar dentine. Given its widespread distribution in non-tetrapod lineages we further propose that elasmodine is a very ancient tissue in vertebrates and predict that it will be found in ancestral rhombic scales and cosmoid scales. PMID:19422423

  20. Effects of ocean acidification on the dissolution rates of reef-coral skeletons

    PubMed Central

    van Woesik, Kelly; van Woesik, Liana; van Woesik, Sandra

    2013-01-01

    Ocean acidification threatens the foundation of tropical coral reefs. This study investigated three aspects of ocean acidification: (i) the rates at which perforate and imperforate coral-colony skeletons passively dissolve when pH is 7.8, which is predicted to occur globally by 2100, (ii) the rates of passive dissolution of corals with respect to coral-colony surface areas, and (iii) the comparative rates of a vertical reef-growth model, incorporating passive dissolution rates, and predicted sea-level rise. By 2100, when the ocean pH is expected to be 7.8, perforate Montipora coral skeletons will lose on average 15 kg CaCO3 m−2 y−1, which is approximately −10.5 mm of vertical reduction of reef framework per year. This rate of passive dissolution is higher than the average rate of reef growth over the last several millennia and suggests that reefs composed of perforate Montipora coral skeletons will have trouble keeping up with sea-level rise under ocean acidification. Reefs composed of primarily imperforate coral skeletons will not likely dissolve as rapidly, but our model shows they will also have trouble keeping up with sea-level rise by 2050. PMID:24282670

  1. Skeletons in the Classroom Closet: Presence/Absence in the "Democratic" Public Sphere of the Academy

    ERIC Educational Resources Information Center

    Provencal, Johanne

    2008-01-01

    The author brings together Paulo Freire and Jurgen Habermas to ask whether dialogue is possible in the classroom or whether, in a culture of rational debate, the classroom becomes more oppressive than democratic? In a voice and style that attempts to invite the skeletons out of the classroom closet, the author asks scholarly readers to lend an…

  2. Effects of skeleton structure on necrosis targeting and clearance properties of radioiodinated dianthrones.

    PubMed

    Zhang, Dongjian; Jiang, Cuihua; Yang, Shengwei; Gao, Meng; Huang, Dejian; Wang, Xiaoning; Shao, Haibo; Feng, Yuanbo; Sun, Ziping; Ni, Yicheng; Zhang, Jian; Yin, Zhiqi

    2016-01-01

    Necrosis avid agents (NAAs) can be used for diagnose of necrosis-related diseases, evaluation of therapeutic responses and targeted therapeutics of tumor. In order to probe into the effects of molecular skeleton structure on necrosis targeting and clearance properties of radioiodinated dianthrones, four dianthrone compounds with the same substituents but different skeletal structures, namely Hypericin (Hyp), protohypericin (ProHyp), emodin dianthrone mesomer (ED-1) and emodin dianthrone raceme (ED-2) were synthesized and radioiodinated. Then radioiodinated dianthrones were evaluated in vitro for their necrosis avidity in A549 lung cancer cells untreated and treated with H2O2. Their biodistribution and pharmacokinetic properties were determined in rat models of induced necrosis. In vitro cell assay revealed that destruction of rigid skeleton structure dramatically reduced their necrosis targeting ability. Animal studies demonstrated that destruction of rigid skeleton structure dramatically reduced the necrotic tissue uptake and speed up the clearance from the most normal tissues for the studied compounds. Among these (131)I-dianthrones, (131)I-Hyp exhibited the highest uptake and persistent retention in necrotic tissues. Hepatic infarction could be clearly visualized by SPECT/CT using (131)I-Hyp as an imaging probe. The results suggest that the skeleton structure of Hyp is the lead structure for further structure optimization of this class of NAAs.

  3. Abstract Morphemes and Lexical Representation: The CV-Skeleton in Arabic

    ERIC Educational Resources Information Center

    Boudelaa, Sami; Marslen-Wilson, Willian D.

    2004-01-01

    Overlaps in form and meaning between morphologically related words have led to ambiguities in interpreting priming effects in studies of lexical organization. In Semitic languages like Arabic, however, linguistic analysis proposes that one of the three component morphemes of a surface word is the CV-Skeleton, an abstract prosodic unit coding the…

  4. Effective Self-Regulated Science Learning through Multimedia-Enriched Skeleton Concept Maps

    ERIC Educational Resources Information Center

    Maree, Ton J.; van Bruggen, Jan M.; Jochems, Wim M. G.

    2013-01-01

    Background: This study combines work on concept mapping with scripted collaborative learning. Purpose: The objective was to examine the effects of self-regulated science learning through scripting students' argumentative interactions during collaborative "multimedia-enriched skeleton concept mapping" on meaningful science learning and retention.…

  5. Occurrence of a young elasmosaurid plesiosaur skeleton from the Late Cretaceous (Maastrichtian) of Antarctica

    USGS Publications Warehouse

    Martin, James E.; Sawyer, J. Foster; Reguero, Marcelo; Case, Judd A.

    2007-01-01

    The most completely articulated fossil skeleton heretofore found on the continent of Antarctica is represented by a juvenile plesiosaur. The specimen was found in the Sandwich Bluff area of Vega Island east of the Antarctic Peninsula from Late Cretaceous (Maastrichtian) marine deposits from the upper Snow Hill Island Formation. The plesiosaur skeleton is represented by a nearly complete torso, partial paddles, and neck and tail sections. Along the ventral margin of the torso are articulated gastralia, some that are unusual in being forked. Numerous small gastroliths are associated within the trunk cavity, indicating that even juveniles ingest gastroliths. Coupled with other known specimens, the skeleton indicates shallow marine environment may have been an area where marine reptiles had their young, and the young remained until reaching maturity prior to facing open marine environments. The morphology of the specimen suggests the skeleton represents a juvenile Mauisaurus, an elasmosaurid plesiosaur taxon originally described from New Zealand and endemic to the Weddellian Province of the austral region.

  6. Multifractal characterization of morphology of human red blood cells membrane skeleton.

    PubMed

    Ţălu, Ş; Stach, S; Kaczmarska, M; Fornal, M; Grodzicki, T; Pohorecki, W; Burda, K

    2016-04-01

    The purpose of this paper is to show applicability of multifractal analysis in investigations of the morphological changes of ultra-structures of red blood cells (RBCs) membrane skeleton measured using atomic force microscopy (AFM). Human RBCs obtained from healthy and hypertensive donors as well as healthy erythrocytes irradiated with neutrons (45 μGy) were studied. The membrane skeleton of the cells was imaged using AFM in a contact mode. Morphological characterization of the three-dimensional RBC surfaces was realized by a multifractal method. The nanometre scale study of human RBCs surface morphology revealed a multifractal geometry. The generalized dimensions Dq and the singularity spectrum f(α) provided quantitative values that characterize the local scale properties of their membrane skeleton organization. Surface characterization was made using areal ISO 25178-2: 2012 topography parameters in combination with AFM topography measurement. The surface structure of human RBCs is complex with hierarchical substructures resulting from the organization of the erythrocyte membrane skeleton. The analysed AFM images confirm a multifractal nature of the surface that could be useful in histology to quantify human RBC architectural changes associated with different disease states. In case of very precise measurements when the red cell surface is not wrinkled even very fine differences can be uncovered as was shown for the erythrocytes treated with a very low dose of ionizing radiation.

  7. Ugi/Himbert Arene/Allene Diels-Alder Cycloaddition to Synthesize Strained Polycyclic Skeleton.

    PubMed

    Cheng, Guangsheng; He, Xiang; Tian, Lumin; Chen, Jiawen; Li, Chunju; Jia, Xueshun; Li, Jian

    2015-11-01

    The present work disclosed an efficient multicomponent reaction of isocyanide, allenic acid, aldehyde (ketone), and aniline. This protocol undergoes Ugi reaction followed by an intramolecular arene/allene Diels-Alder sequence, thus providing a rapid access to synthesize strained polycyclic skeletons.

  8. Elastic properties of external cortical bone in the craniofacial skeleton of the rhesus monkey.

    PubMed

    Wang, Qian; Dechow, Paul C

    2006-11-01

    Knowledge of elastic properties and of their variation in the cortical bone of the craniofacial skeleton is indispensable for creating accurate finite-element models to explore the biomechanics and adaptation of the skull in primates. In this study, we measured elastic properties of the external cortex of the rhesus monkey craniofacial skeleton, using an ultrasonic technique. Twenty-eight cylindrical cortical specimens were removed from each of six craniofacial skeletons of adult Macaca mulatta. Thickness, density, and a set of longitudinal and transverse ultrasonic velocities were measured on each specimen to allow calculation of the elastic properties in three dimensions, according to equations derived from Newton's second law and Hooke's law. The axes of maximum stiffness were determined by fitting longitudinal velocities measured along the perimeter of each cortical specimen to a sinusoidal function. Results showed significant differences in elastic properties between different functional areas of the rhesus cranium, and that many sites have a consistent orientation of maximum stiffness among specimens. Overall, the cortical bones of the rhesus monkey skull can be modeled as orthotropic in many regions, and as transversely isotropic in some regions, e.g., the supraorbital region. There are differences from human crania, suggesting that structural differences in skeletal form relate to differences in cortical material properties across species. These differences also suggest that we require more comparative data on elastic properties in primate craniofacial skeletons to explore effectively the functional significance of these differences, especially when these differences are elucidated through modeling approaches, such as finite-element modeling.

  9. Anisoplanatic Imaging Through Turbulence Using Principal Component Analysis

    NASA Astrophysics Data System (ADS)

    Baena-Gallé, R.; Katsaggelos, A.; Molina, R.; Mateos, J.; Gladysz, S.

    The performance of optical systems is highly degraded by atmospheric turbulence when observing both vertically (e.g., astronomy, remote sensing) or horizontally (long-range surveillance). This problem can be partially alleviated using adaptive optics (AO) but only for small fields of view (FOV) described by the isoplanatic angle for which the turbulence-induced aberrations are considered constant. Additionally, this problem can also be tackled using post-processing techniques such as deconvolution algorithms which take into account the variability of the point spread function (PSF) in anisoplanatic conditions. Variability of the PSF across the FOV in anisoplanatc imagery can be described using principal component analysis (Karhunen-Loeve transform). Then, a certain number of variable PSFs can be used to create new basis functions, called principal components (PC), which can be considered constant across the FOV and, therefore, potentially be used to perform global deconvolution. Our aim is twofold: firstly, to describe the shape and statistics of the anisoplanatic PSF for single-conjugate AO systems with only a few parameters and, secondly, using this information to obtain the set of PSFs at positions in the FOV so that the associated variability is properly described. Additionally, these PSFs are to be decomposed into PCs. Finally, the entire FOV is deconvolved globally using deconvolution algorithms which account for uncertainties involved in local estimates of the PSFs. Our approach is tested on simulated, single-conjugate AO data.

  10. GPR anomaly detection with robust principal component analysis

    NASA Astrophysics Data System (ADS)

    Masarik, Matthew P.; Burns, Joseph; Thelen, Brian T.; Kelly, Jack; Havens, Timothy C.

    2015-05-01

    This paper investigates the application of Robust Principal Component Analysis (RPCA) to ground penetrating radar as a means to improve GPR anomaly detection. The method consists of a preprocessing routine to smoothly align the ground and remove the ground response (haircut), followed by mapping to the frequency domain, applying RPCA, and then mapping the sparse component of the RPCA decomposition back to the time domain. A prescreener is then applied to the time-domain sparse component to perform anomaly detection. The emphasis of the RPCA algorithm on sparsity has the effect of significantly increasing the apparent signal-to-clutter ratio (SCR) as compared to the original data, thereby enabling improved anomaly detection. This method is compared to detrending (spatial-mean removal) and classical principal component analysis (PCA), and the RPCA-based processing is seen to provide substantial improvements in the apparent SCR over both of these alternative processing schemes. In particular, the algorithm has been applied to both field collected impulse GPR data and has shown significant improvement in terms of the ROC curve relative to detrending and PCA.

  11. The 3D skeleton: tracing the filamentary structure of the Universe

    NASA Astrophysics Data System (ADS)

    Sousbie, T.; Pichon, C.; Colombi, S.; Novikov, D.; Pogosyan, D.

    2008-02-01

    The skeleton formalism, which aims at extracting and quantifying the filamentary structure of our Universe, is generalized to 3D density fields. A numerical method for computing a local approximation of the skeleton is presented and validated here on Gaussian random fields. It involves solving equation , where ∇ρ and are the gradient and Hessian matrix of the field. This method traces well the filamentary structure in 3D fields such as those produced by numerical simulations of the dark matter distribution on large scales, and is insensitive to monotonic biasing. Two of its characteristics, namely its length and differential length, are analysed for Gaussian random fields. Its differential length per unit normalized density contrast scales like the probability distribution function of the underlying density contrast times the total length times a quadratic Edgeworth correction involving the square of the spectral parameter. The total length-scales like the inverse square smoothing length, with a scaling factor given by 0.21 (5.28 + n) where n is the power index of the underlying field. This dependency implies that the total length can be used to constrain the shape of the underlying power spectrum, hence the cosmology. Possible applications of the skeleton to galaxy formation and cosmology are discussed. As an illustration, the orientation of the spin of dark haloes and the orientation of the flow near the skeleton is computed for cosmological dark matter simulations. The flow is laminar along the filaments, while spins of dark haloes within 500 kpc of the skeleton are preferentially orthogonal to the direction of the flow at a level of 25 per cent.

  12. Use of endogeneous, stable lead isotopes to determine release of lead from the skeleton

    SciTech Connect

    Smith, D. |; Flegal, R.; Osterioh, J.D.

    1996-01-01

    The stable lead isotope methodology can be used to study the release of lead from bone into the circulation because of its potential to distinguish circulatory lead form {open_quotes}older{close_quotes} and isotopically different skeletal lead that may have been accumulated years or decades earlier. Here we report the initial results from a larger ongoing study that evaluates the skeleton as a source of lead to the circulation in environmentally exposed human subjects. Lead concentrations and stable lead isotopic compositions were measured in blood and trabecular bone samples obtained from five patients who underwent total hip or knee joint replacement. All subjects contained low blood (1-6 {mu}g/dl) and bone (0.6-7 {mu}g/g dry weight) lead concentrations typical of environmentally exposed individuals. There were relatively large differences in the lead isotopic compositions between the paired blood and bone samples from each subject. These isotopic differences are attributed to differences in the lead isotopic compositions of past versus current lead exposures and to the long elimination half-life of lead in the skeleton compared to lead in the circulation. Based on these data, we determined that the skeleton contributed 40-70% of the lead in the blood of these subjects. This initial study demonstrates the utility of the stable lead isotope methodology for investigating the release of lead from the skeleton. It also shows that the skeleton can be an important endogenous source of lead exposure in environmentally exposed humans. 54 refs., 3 figs., 1 tab.

  13. Use of endogenous, stable lead isotopes to determine release of lead from the skeleton.

    PubMed Central

    Smith, D R; Osterloh, J D; Flegal, A R

    1996-01-01

    The stable lead isotope methodology can be used to study the release of lead from bone into the circulation because of its potential to distinguish circulatory lead from "older" and isotopically different skeletal lead that may have been accumulated years or decades earlier. Here we report the initial results from a larger ongoing study that evaluates the skeleton as a source of lead to the circulation in environmentally exposed human subjects. Lead concentrations and stable lead isotopic compositions were measured in blood and trabecular bone samples obtained from five patients who underwent total hip or knee joint replacement. All subjects contained low blood (1-6 micrograms/dl) and bone (0.6-7 micrograms/g dry weight) lead concentrations typical of environmentally exposed individuals. There were relatively large differences in the lead isotopic compositions between the paired blood and bone samples from each subject. These isotopic differences are attributed to differences in the lead isotopic compositions of past versus current lead exposures and to the long elimination half-life of lead in the skeleton compared to lead in the circulation. Based on these data, we determined that the skeleton contributed 40-70% of the lead in the blood of these subjects. This initial study demonstrates the utility of the stable lead isotope methodology for investigating the release of lead from the skeleton. It also shows that the skeleton can be an important endogenous source of lead exposure in environmentally exposed humans. Images Figure 1. Figure 2. A Figure 2. B Figure 3. PMID:8834863

  14. The Rookie's Playbook: Insights and Dirt for New Principals.

    ERIC Educational Resources Information Center

    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)

  15. Aspiring Principals' Perception of the Challenges of Beginning Principals and the Support That They Need

    ERIC Educational Resources Information Center

    Ng, Pak Tee

    2015-01-01

    This paper presents the results of an exploratory research project about the perception of aspiring principals regarding the challenges of beginning principals and the support that they need. These aspiring principals are participants on the Leaders in Education Programme (LEP) in Singapore. According to the research findings, the LEP participants…

  16. Principal Time Management Skills: Explaining Patterns in Principals' Time Use, Job Stress, and Perceived Effectiveness

    ERIC Educational Resources Information Center

    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:…

  17. How Do School Districts Treat K-12 Principals and Principal Candidates with Online Credentials?

    ERIC Educational Resources Information Center

    Richardson, Jayson W.; McLeod, Scott; Dikkers, Amy Garrett

    2011-01-01

    This study was designed to understand how school districts treat their current principals and principal candidates who have taken online courses or who have earned online degrees. Through a survey of 105 human resources directors in K-12 schools across the USA, the study found five major themes: (1) districts are reluctant to hire principals with…

  18. What Is a "Good" Principal? Perspectives of Aspiring Principals in Singapore

    ERIC Educational Resources Information Center

    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…

  19. Principals and Blogs: In What Ways Does Blogging Support the Practices of School Principals?

    ERIC Educational Resources Information Center

    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,…

  20. Exploring the Impact of Applicants' Gender and Religion on Principals' Screening Decisions for Assistant Principal Applicants

    ERIC Educational Resources Information Center

    Bon, Susan C.

    2009-01-01

    In this experimental study, a national random sample of high school principals (stratified by gender) were asked to evaluate hypothetical applicants whose resumes varied by religion (Jewish, Catholic, nondenominational) and gender (male, female) for employment as assistant principals. Results reveal that male principals rate all applicants higher…