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Sample records for principal skeleton algorithm

  1. A simple algorithm for computing positively weighted straight skeletons of monotone polygons.

    PubMed

    Biedl, Therese; Held, Martin; Huber, Stefan; Kaaser, Dominik; Palfrader, Peter

    2015-02-01

    We study the characteristics of straight skeletons of monotone polygonal chains and use them to devise an algorithm for computing positively weighted straight skeletons of monotone polygons. Our algorithm runs in [Formula: see text] time and [Formula: see text] space, where n denotes the number of vertices of the polygon.

  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. 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

  4. Skil: An imperative language with algorithmic skeletons for efficient distributed programming

    SciTech Connect

    Botorog, G.H.; Kuchen, H.

    1996-12-31

    In this paper we present Skil, an imperative language enhanced with higher-order functions and currying, as well as with a polymorphic type system. The high level of Skil allows the integration of algorithmic skeletons, i.e. of higher-order functions representing parallel computation patterns. At the same time, the language can be efficiently implemented. After describing a series of skeletons which work with distributed arrays, we give two examples of parallel programs implemented on the basis of skeletons, namely shortest paths in graphs and Gaussian elimination. Runtime measurements show that we approach the efficiency of message-passing C up to a factor between 1 and 2.5.

  5. A principal component analysis of the relationship between the external body shape and internal skeleton for the upper body.

    PubMed

    Nerot, A; Skalli, W; Wang, X

    2016-10-03

    Recent progress in 3D scanning technologies allows easy access to 3D human body envelope. To create personalized human models with an articulated linkage for realistic re-posturing and motion analyses, an accurate estimation of internal skeleton points, including joint centers, from the external envelope is required. For this research project, 3D reconstructions of both internal skeleton and external envelope from low dose biplanar X-rays of 40 male adults were obtained. Using principal component analysis technique (PCA), a low-dimensional dataset was used to predict internal points of the upper body from the trunk envelope. A least squares method was used to find PC scores that fit the PCA-based model to the envelope of a new subject. To validate the proposed approach, estimated internal points were evaluated using a leave-one-out (LOO) procedure, i.e. successively considering each individual from our dataset as an extra-subject. In addition, different methods were proposed to reduce the variability in data and improve the performance of the PCA-based prediction. The best method was considered as the one providing the smallest errors between estimated and reference internal points with an average error of 8.3mm anterior-posteriorly, 6.7mm laterally and 6.5mm vertically. As the proposed approach relies on few or no bony landmarks, it could be easily applicable and generalizable to surface scans from any devices. Combined with automatic body scanning techniques, this study could potentially constitute a new step towards automatic generation of external/internal subject-specific manikins.

  6. An Algorithm for Constructing Principal Geodesics in Phylogenetic Treespace.

    PubMed

    Nye, Tom M W

    2014-01-01

    Most phylogenetic analyses result in a sample of trees, but summarizing and visualizing these samples can be challenging. Consensus trees often provide limited information about a sample, and so methods such as consensus networks, clustering and multidimensional scaling have been developed and applied to tree samples. This paper describes a stochastic algorithm for constructing a principal geodesic or line through treespace which is analogous to the first principal component in standard principal components analysis. A principal geodesic summarizes the most variable features of a sample of trees, in terms of both tree topology and branch lengths, and it can be visualized as an animation of smoothly changing trees. The algorithm performs a stochastic search through parameter space for a geodesic which minimizes the sum of squared projected distances of the data points. This procedure aims to identify the globally optimal principal geodesic, though convergence to locally optimal geodesics is possible. The methodology is illustrated by constructing principal geodesics for experimental and simulated data sets, demonstrating the insight into samples of trees that can be gained and how the method improves on a previously published approach. A java package called GeoPhytter for constructing and visualizing principal geodesics is freely available from www.ncl.ac.uk/ ntmwn/geophytter.

  7. A combined approach to cartographic displacement for buildings based on skeleton and improved elastic beam algorithm.

    PubMed

    Liu, Yuangang; Guo, Qingsheng; Sun, Yageng; Ma, Xiaoya

    2014-01-01

    Scale reduction from source to target maps inevitably leads to conflicts of map symbols in cartography and geographic information systems (GIS). Displacement is one of the most important map generalization operators and it can be used to resolve the problems that arise from conflict among two or more map objects. In this paper, we propose a combined approach based on constraint Delaunay triangulation (CDT) skeleton and improved elastic beam algorithm for automated building displacement. In this approach, map data sets are first partitioned. Then the displacement operation is conducted in each partition as a cyclic and iterative process of conflict detection and resolution. In the iteration, the skeleton of the gap spaces is extracted using CDT. It then serves as an enhanced data model to detect conflicts and construct the proximity graph. Then, the proximity graph is adjusted using local grouping information. Under the action of forces derived from the detected conflicts, the proximity graph is deformed using the improved elastic beam algorithm. In this way, buildings are displaced to find an optimal compromise between related cartographic constraints. To validate this approach, two topographic map data sets (i.e., urban and suburban areas) were tested. The results were reasonable with respect to each constraint when the density of the map was not extremely high. In summary, the improvements include (1) an automated parameter-setting method for elastic beams, (2) explicit enforcement regarding the positional accuracy constraint, added by introducing drag forces, (3) preservation of local building groups through displacement over an adjusted proximity graph, and (4) an iterative strategy that is more likely to resolve the proximity conflicts than the one used in the existing elastic beam algorithm.

  8. A Combined Approach to Cartographic Displacement for Buildings Based on Skeleton and Improved Elastic Beam Algorithm

    PubMed Central

    Liu, Yuangang; Guo, Qingsheng; Sun, Yageng; Ma, Xiaoya

    2014-01-01

    Scale reduction from source to target maps inevitably leads to conflicts of map symbols in cartography and geographic information systems (GIS). Displacement is one of the most important map generalization operators and it can be used to resolve the problems that arise from conflict among two or more map objects. In this paper, we propose a combined approach based on constraint Delaunay triangulation (CDT) skeleton and improved elastic beam algorithm for automated building displacement. In this approach, map data sets are first partitioned. Then the displacement operation is conducted in each partition as a cyclic and iterative process of conflict detection and resolution. In the iteration, the skeleton of the gap spaces is extracted using CDT. It then serves as an enhanced data model to detect conflicts and construct the proximity graph. Then, the proximity graph is adjusted using local grouping information. Under the action of forces derived from the detected conflicts, the proximity graph is deformed using the improved elastic beam algorithm. In this way, buildings are displaced to find an optimal compromise between related cartographic constraints. To validate this approach, two topographic map data sets (i.e., urban and suburban areas) were tested. The results were reasonable with respect to each constraint when the density of the map was not extremely high. In summary, the improvements include (1) an automated parameter-setting method for elastic beams, (2) explicit enforcement regarding the positional accuracy constraint, added by introducing drag forces, (3) preservation of local building groups through displacement over an adjusted proximity graph, and (4) an iterative strategy that is more likely to resolve the proximity conflicts than the one used in the existing elastic beam algorithm. PMID:25470727

  9. MDL constrained 3-D grayscale skeletonization algorithm for automated extraction of dendrites and spines from fluorescence confocal images.

    PubMed

    Yuan, Xiaosong; Trachtenberg, Joshua T; Potter, Steve M; Roysam, Badrinath

    2009-12-01

    This paper presents a method for improved automatic delineation of dendrites and spines from three-dimensional (3-D) images of neurons acquired by confocal or multi-photon fluorescence microscopy. The core advance presented here is a direct grayscale skeletonization algorithm that is constrained by a structural complexity penalty using the minimum description length (MDL) principle, and additional neuroanatomy-specific constraints. The 3-D skeleton is extracted directly from the grayscale image data, avoiding errors introduced by image binarization. The MDL method achieves a practical tradeoff between the complexity of the skeleton and its coverage of the fluorescence signal. Additional advances include the use of 3-D spline smoothing of dendrites to improve spine detection, and graph-theoretic algorithms to explore and extract the dendritic structure from the grayscale skeleton using an intensity-weighted minimum spanning tree (IW-MST) algorithm. This algorithm was evaluated on 30 datasets organized in 8 groups from multiple laboratories. Spines were detected with false negative rates less than 10% on most datasets (the average is 7.1%), and the average false positive rate was 11.8%. The software is available in open source form.

  10. Skeletonization algorithm-based blood vessel quantification using in vivo 3D photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Meiburger, K. M.; Nam, S. Y.; Chung, E.; Suggs, L. J.; Emelianov, S. Y.; Molinari, F.

    2016-11-01

    Blood vessels are the only system to provide nutrients and oxygen to every part of the body. Many diseases can have significant effects on blood vessel formation, so that the vascular network can be a cue to assess malicious tumor and ischemic tissues. Various imaging techniques can visualize blood vessel structure, but their applications are often constrained by either expensive costs, contrast agents, ionizing radiations, or a combination of the above. Photoacoustic imaging combines the high-contrast and spectroscopic-based specificity of optical imaging with the high spatial resolution of ultrasound imaging, and image contrast depends on optical absorption. This enables the detection of light absorbing chromophores such as hemoglobin with a greater penetration depth compared to purely optical techniques. We present here a skeletonization algorithm for vessel architectural analysis using non-invasive photoacoustic 3D images acquired without the administration of any exogenous contrast agents. 3D photoacoustic images were acquired on rats (n  =  4) in two different time points: before and after a burn surgery. A skeletonization technique based on the application of a vesselness filter and medial axis extraction is proposed to extract the vessel structure from the image data and six vascular parameters (number of vascular trees (NT), vascular density (VD), number of branches (NB), 2D distance metric (DM), inflection count metric (ICM), and sum of angles metric (SOAM)) were calculated from the skeleton. The parameters were compared (1) in locations with and without the burn wound on the same day and (2) in the same anatomic location before (control) and after the burn surgery. Four out of the six descriptors were statistically different (VD, NB, DM, ICM, p  <  0.05) when comparing two anatomic locations on the same day and when considering the same anatomic location at two separate times (i.e. before and after burn surgery). The study demonstrates an

  11. 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.

  12. [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.

  13. 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.

  14. 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.

  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. Accelerated convergence of neural network system identification algorithms via principal component analysis

    NASA Astrophysics Data System (ADS)

    Hyland, David C.; Davis, Lawrence D.; Denoyer, Keith K.

    1998-12-01

    While significant theoretical and experimental progress has been made in the development of neural network-based systems for the autonomous identification and control of space platforms, there remain important unresolved issues associated with the reliable prediction of convergence speed and the avoidance of inordinately slow convergence. To speed convergence of neural identifiers, we introduce the preprocessing of identifier inputs using Principal Component Analysis (PCA) algorithms. Which automatically transform the neural identifier's external inputs so as to make the correlation matrix identity, resulting in enormous improvements in the convergence speed of the neural identifier. From a study of several such algorithms, we developed a new PCA approach which exhibits excellent convergence properties, insensitivity to noise and reliable accuracy.

  17. Intensity-Based Skeletonization of CryoEM Gray-Scale Images Using a True Segmentation-Free Algorithm

    PubMed Central

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

    2014-01-01

    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. PMID:24384713

  18. A robust principal component analysis algorithm for EEG-based vigilance estimation.

    PubMed

    Shi, Li-Chen; Duan, Ruo-Nan; Lu, Bao-Liang

    2013-01-01

    Feature dimensionality reduction methods with robustness have a great significance for making better use of EEG data, since EEG features are usually high-dimensional and contain a lot of noise. In this paper, a robust principal component analysis (PCA) algorithm is introduced to reduce the dimension of EEG features for vigilance estimation. The performance is compared with that of standard PCA, L1-norm PCA, sparse PCA, and robust PCA in feature dimension reduction on an EEG data set of twenty-three subjects. To evaluate the performance of these algorithms, smoothed differential entropy features are used as the vigilance related EEG features. Experimental results demonstrate that the robustness and performance of robust PCA are better than other algorithms for both off-line and on-line vigilance estimation. The average RMSE (root mean square errors) of vigilance estimation was 0.158 when robust PCA was applied to reduce the dimensionality of features, while the average RMSE was 0.172 when standard PCA was used in the same task.

  19. Diagnosis of atherosclerosis in human carotid artery by FT-Raman spectroscopy: Principal Components Analysis algorithm

    NASA Astrophysics Data System (ADS)

    Nogueira, Grazielle V.; Silveira, Landulfo, Jr.; Martin, Airton A.; Zangaro, Renato A.; Pacheco, Marcos T.; Chavantes, Maria C.; Zampieri, Marcelo; Pasqualucci, Carlos A. G.

    2004-07-01

    FT- Raman Spectroscopy (FT-Raman) could allow identification and evaluation of human atherosclerotic lesions. A Raman spectrum can provide biochemical information of arteries which can help identifying the disease status and evolution. In this study, it is shown the results of FT-Raman for identification of human carotid arteries in vitro. Fragments of human carotid arteries were analyzed using a FT-Raman spectrometer with a Nd:YAG laser at 1064nm operating at an excitation power of 300mW. Spectra were obtained with 250 scans and spectral resolution of 4 cm-1. Each collection time was approximately 8 min. A total of 75 carotid fragments were spectroscopically scanned and FT-Raman results were compared with histopathology. Principal Components Analysis (PCA) was used to model an algorithm for tissue classification into three categories: normal, atherosclerotic plaque without calcification and atherosclerotic plaque with calcification. Non-atherosclerotic (normal) artery, atherosclerotic plaque and calcified plaque exhibit different spectral signatures related to biochemicals presented in each tissue type, such as, bands of collagen and elastin (proteins), cholesterol and its esters and calcium hydroxyapatite and carbonate apatite respectively. Results show that there is 96% match between classifications based on PCA algorithm and histopathology. The diagnostic applied over all 75 samples had sensitivity and specificity of about 89% and 100%, respectively, for atherosclerotic plaque and 100% and 98% for calcified plaque.

  20. 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.

  1. X-ray - skeleton

    MedlinePlus

    ... medlineplus.gov/ency/article/003381.htm X-ray - skeleton To use the sharing features on this page, ... ray views may be uncomfortable. If the whole skeleton is being imaged, the test usually takes 1 ...

  2. Weighted straight skeletons in the plane.

    PubMed

    Biedl, Therese; Held, Martin; Huber, Stefan; Kaaser, Dominik; Palfrader, Peter

    2015-02-01

    We investigate weighted straight skeletons from a geometric, graph-theoretical, and combinatorial point of view. We start with a thorough definition and shed light on some ambiguity issues in the procedural definition. We investigate the geometry, combinatorics, and topology of faces and the roof model, and we discuss in which cases a weighted straight skeleton is connected. Finally, we show that the weighted straight skeleton of even a simple polygon may be non-planar and may contain cycles, and we discuss under which restrictions on the weights and/or the input polygon the weighted straight skeleton still behaves similar to its unweighted counterpart. In particular, we obtain a non-procedural description and a linear-time construction algorithm for the straight skeleton of strictly convex polygons with arbitrary weights.

  3. 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

  4. 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

  5. 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.

  6. 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…

  7. 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

  8. 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.

  9. Diagnosing basal cell carcinoma in vivo by near-infrared Raman spectroscopy: a Principal Components Analysis discrimination algorithm

    NASA Astrophysics Data System (ADS)

    Silveira, Landulfo, Jr.; Silveira, Fabrício L.; Bodanese, Benito; Pacheco, Marcos Tadeu T.; Zângaro, Renato A.

    2012-02-01

    This work demonstrated the discrimination among basal cell carcinoma (BCC) and normal human skin in vivo using near-infrared Raman spectroscopy. Spectra were obtained in the suspected lesion prior resectional surgery. After tissue withdrawn, biopsy fragments were submitted to histopathology. Spectra were also obtained in the adjacent, clinically normal skin. Raman spectra were measured using a Raman spectrometer (830 nm) with a fiber Raman probe. By comparing the mean spectra of BCC with the normal skin, it has been found important differences in the 800-1000 cm-1 and 1250-1350 cm-1 (vibrations of C-C and amide III, respectively, from lipids and proteins). A discrimination algorithm based on Principal Components Analysis and Mahalanobis distance (PCA/MD) could discriminate the spectra of both tissues with high sensitivity and specificity.

  10. 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)

  11. 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.

  12. 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.

  13. [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.

  14. 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.

  15. 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.

  16. Connexins in The Skeleton

    PubMed Central

    Stains, Joseph P.; Civitelli, Roberto

    2016-01-01

    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. PMID:26740471

  17. 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…

  18. 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.

  19. Daily PM2.5 concentration prediction based on principal component analysis and LSSVM optimized by cuckoo search algorithm.

    PubMed

    Sun, Wei; Sun, Jingyi

    2017-03-01

    Increased attention has been paid to PM2.5 pollution in China. Due to its detrimental effects on environment and health, it is important to establish a PM2.5 concentration forecasting model with high precision for its monitoring and controlling. This paper presents a novel hybrid model based on principal component analysis (PCA) and least squares support vector machine (LSSVM) optimized by cuckoo search (CS). First PCA is adopted to extract original features and reduce dimension for input selection. Then LSSVM is applied to predict the daily PM2.5 concentration. The parameters in LSSVM are fine-tuned by CS to improve its generalization. An experiment study reveals that the proposed approach outperforms a single LSSVM model with default parameters and a general regression neural network (GRNN) model in PM2.5 concentration prediction. Therefore the established model presents the potential to be applied to air quality forecasting systems.

  20. 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.

  1. 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.

  2. Interim Principals.

    ERIC Educational Resources Information Center

    Beem, Kate

    2003-01-01

    An interim principal can buy a school district time to land a permanent successor. Also lists where to find an interim principal; the interim's steadying influence; Bob Wallace's wild ride as an interim principal in post-retirement; and Roger Prosise's rationale for turning to an interim appointment. (MLF)

  3. SAR image segmentation using skeleton-based fuzzy clustering

    NASA Astrophysics Data System (ADS)

    Cao, Yun Yi; Chen, Yan Qiu

    2003-06-01

    SAR image segmentation can be converted to a clustering problem in which pixels or small patches are grouped together based on local feature information. In this paper, we present a novel framework for segmentation. The segmentation goal is achieved by unsupervised clustering upon characteristic descriptors extracted from local patches. The mixture model of characteristic descriptor, which combines intensity and texture feature, is investigated. The unsupervised algorithm is derived from the recently proposed Skeleton-Based Data Labeling method. Skeletons are constructed as prototypes of clusters to represent arbitrary latent structures in image data. Segmentation using Skeleton-Based Fuzzy Clustering is able to detect the types of surfaces appeared in SAR images automatically without any user input.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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)

  9. 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.

  10. 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…

  11. 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…

  12. Efficient curve-skeleton computation for the analysis of biomedical 3d images - biomed 2010.

    PubMed

    Brun, Francesco; Dreossi, Diego

    2010-01-01

    Advances in three dimensional (3D) biomedical imaging techniques, such as magnetic resonance (MR) and computed tomography (CT), make it easy to reconstruct high quality 3D models of portions of human body and other biological specimens. A major challenge lies in the quantitative analysis of the resulting models thus allowing a more comprehensive characterization of the object under investigation. An interesting approach is based on curve-skeleton (or medial axis) extraction, which gives basic information concerning the topology and the geometry. Curve-skeletons have been applied in the analysis of vascular networks and the diagnosis of tracheal stenoses as well as a 3D flight path in virtual endoscopy. However curve-skeleton computation is a crucial task. An effective skeletonization algorithm was introduced by N. Cornea in [1] but it lacks in computational performances. Thanks to the advances in imaging techniques the resolution of 3D images is increasing more and more, therefore there is the need for efficient algorithms in order to analyze significant Volumes of Interest (VOIs). In the present paper an improved skeletonization algorithm based on the idea proposed in [1] is presented. A computational comparison between the original and the proposed method is also reported. The obtained results show that the proposed method allows a significant computational improvement making more appealing the adoption of the skeleton representation in biomedical image analysis applications.

  13. 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.

  14. Navigable points estimation for mobile robots using binary image skeletonization

    NASA Astrophysics Data System (ADS)

    Martinez S., Fernando; Jacinto G., Edwar; Montiel A., Holman

    2017-02-01

    This paper describes the use of image skeletonization for the estimation of all the navigable points, inside a scene of mobile robots navigation. Those points are used for computing a valid navigation path, using standard methods. The main idea is to find the middle and the extreme points of the obstacles in the scene, taking into account the robot size, and create a map of navigable points, in order to reduce the amount of information for the planning algorithm. Those points are located by means of the skeletonization of a binary image of the obstacles and the scene background, along with some other digital image processing algorithms. The proposed algorithm automatically gives a variable number of navigable points per obstacle, depending on the complexity of its shape. As well as, the way how the algorithm can change some of their parameters in order to change the final number of the resultant key points is shown. The results shown here were obtained applying different kinds of digital image processing algorithms on static scenes.

  15. 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.

  16. 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

  17. 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

  18. Fast Steerable Principal Component Analysis.

    PubMed

    Zhao, Zhizhen; Shkolnisky, Yoel; Singer, Amit

    2016-03-01

    Cryo-electron microscopy nowadays often requires the analysis of hundreds of thousands of 2-D images as large as a few hundred pixels in each direction. Here, we introduce an algorithm that efficiently and accurately performs principal component analysis (PCA) for a large set of 2-D images, and, for each image, the set of its uniform rotations in the plane and their reflections. For a dataset consisting of n images of size L × L pixels, the computational complexity of our algorithm is O(nL(3) + L(4)), while existing algorithms take O(nL(4)). The new algorithm computes the expansion coefficients of the images in a Fourier-Bessel basis efficiently using the nonuniform fast Fourier transform. We compare the accuracy and efficiency of the new algorithm with traditional PCA and existing algorithms for steerable PCA.

  19. Distraction Osteogenesis of the Craniofacial Skeleton.

    PubMed

    Yu, Jack C.; Fearon, Jeffrey; Havlik, Robert J.; Buchman, Steve R.; Polley, John W.

    2004-07-01

    LEARNING OBJECTIVES:: After studying this article, the participant should be able to: 1. Review the biomechanical principles and pertinent cellular and molecular biology of distraction osteogenesis of the craniofacial skeleton. 2. Describe the clinical indications and applications of distraction osteogenesis of the craniofacial skeleton. 3. Describe maxillary, mandibular, midface, and calvarial procedures in distraction osteogenesis. 4. Discuss the clinical outcomes and complications of distraction osteogenesis of the craniofacial skeleton.The year 2002 marked the end of the first decade in clinical distraction osteogenesis of the craniofacial skeleton. In this short period, its application has increased exponentially. More than 3000 cases have been performed according to a recent survey, and more than 700 articles have been written on this subject in the MEDLINE database since 1996. It is a powerful surgical tool and enables surgeons to achieve results not previously attainable. Despite all this, distraction osteogenesis is practiced by only a small number of plastic surgeons. This article reviews the biomechanical principles; the pertinent cellular and molecular biology; and the clinical indications, applications, controversies, and complications of distraction osteogenesis of the craniofacial skeleton.

  20. 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)).

  1. 3-D vascular skeleton extraction and decomposition.

    PubMed

    Chowriappa, Ashirwad; Seo, Yong; Salunke, Sarthak; Mokin, Maxim; Kan, Peter; Scott, Peter

    2014-01-01

    We introduce a novel vascular skeleton extraction and decomposition technique for computer-assisted diagnosis and analysis. We start by addressing the problem of vascular decomposition as a cluster optimization problem and present a methodology for weighted convex approximations. Decomposed vessel structures are then grouped using the vessel skeleton, extracted using a Laplace-based operator. The method is validated using presegmented sections of vasculature archived for 98 aneurysms in 112 patients. We test first for vascular decomposition and next for vessel skeleton extraction. The proposed method produced promising results with an estimated 80.5% of the vessel sections correctly decomposed and 92.9% of the vessel sections having the correct number of skeletal branches, identified by a clinical radiological expert. Next, the method was validated on longitudinal study data from n = 4 subjects, where vascular skeleton extraction and decomposition was performed. Volumetric and surface area comparisons were made between expert segmented sections and the proposed approach on sections containing aneurysms. Results suggest that the method is able to detect changes in aneurysm volumes and surface areas close to that segmented by an expert.

  2. 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

  3. 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

  4. 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.

  5. Solving the Principal Shortage.

    ERIC Educational Resources Information Center

    Potter, Les

    2001-01-01

    Districts can quickly relieve the principal shortage by hiring recently retired principals and aspiring assistant principals, keeping good principals on the job, reconsidering early retirement options, providing monetary incentives, and recruiting candidates from local universities and outside education. Nurturing assistant principals is the best…

  6. Skeleton pruning by contour partitioning with discrete curve evolution.

    PubMed

    Bai, Xiang; Latecki, Longin Jan; Liu, Wen-Yu

    2007-03-01

    In this paper, we introduce a new skeleton pruning method based on contour partitioning. Any contour partition can be used, but the partitions obtained by Discrete Curve Evolution (DCE) yield excellent results. The theoretical properties and the experiments presented demonstrate that obtained skeletons are in accord with human visual perception and stable, even in the presence of significant noise and shape variations, and have the same topology as the original skeletons. In particular, we have proven that the proposed approach never produces spurious branches, which are common when using the known skeleton pruning methods. Moreover, the proposed pruning method does not displace the skeleton points. Consequently, all skeleton points are centers of maximal disks. Again, many existing methods displace skeleton points in order to produces pruned skeletons.

  7. Miocene Coral Skeleton Rare Earth Element Patterns Reflect River Discharge

    NASA Astrophysics Data System (ADS)

    Mertz-Kraus, R.; Brachert, T. C.; Jochum, K. P.

    2010-12-01

    reconstructions suggest the reef to have grown close to a river mouth. The calculated mixing ratio corresponds to a SSS of the ambient water >34 ‰ compatible with environmental conditions favorable for coral growth. As possible sources of the REE transported by river water, weathering products of Cretan hinterland rocks must be considered. During the Miocene, drained hinterland was formed by a diversity of magmatic, metamorphic and sedimentary lithologies, essentially represented by granitoids, ophiolitic rocks, siliciclastic sediments and carbonates. A detailed identification of sources as well as quantification of corresponding fractions of REE contributing to the bulk river water component is principally possible in cases where the drained system shows a more limited variation in rock lithologies, however, is difficult to apply to the complex Cretan situation. This study demonstrates that the REE patterns of coral skeletons can be suitable to reconstruct the bulk REE composition of the drainage system in the reef’s hinterland. Also, we suggest to use REE/Ca and Ba/Ca ratios likewise in order to identify fluctuations in river discharge to marine environments.

  8. 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.

  9. The facial skeleton: Armor to the brain?

    PubMed Central

    Patil, Satishkumar G.; Patil, Bindu S.; Joshi, Udupikrishna; Allurkar, Soumya; Japatti, Sharanabasappa; Munnangi, Ashwini

    2016-01-01

    Background: With the development of urban setting worldwide, the major issue of concern is the increase in the mortality rate in the population due to road traffic accidents. The face, being the most exposed region is susceptible to injuries and maybe associated with injuries to the adjacent neuro-cranium. The literature has conflicting views on the relationship between facial fractures and head injuries with some authors opining that the facial skeleton cushions the brain while some other authors claim that the facial fractures act as indicators for head injuries. Objectives: To analyze the correlation between the facial fractures and head injuries and to assess if the facial skeleton acts to protect the brain from injury. Patients and Methods: A prospective study that included patients who reported to the emergency department of Basaveswar Teaching and General Hospital, Gulbarga, during 2 years, between August 2013 and July 2015 was conducted. A total of 100 patients with facial fractures were enrolled in the study. Results: Head injuries were sustained by 51 patients in the study. Maximum number of patients was in the age group of 20–29 with a male to female ratio of 10.1:1. The mandible was the most frequently fractured bone in the facial skeleton followed by the zygomatico-maxillary complex. A majority (96%) of patients with head injuries had fractures of either the upper third or the middle third of the face. Contusions and pneumocephalus were the most common head injury encountered. The Glasgow Coma Scale score was significantly lower in patients with associated head injuries as compared to those patients with facial trauma alone. The mortality rate in the study was 2% with both the victims having sustained middle third and upper third fractures respectively with associated head injuries. Conclusion: The facial skeleton does not act to cushion the brain from injury but, in fact, the facial trauma victims should be considered potential head injury patients

  10. Performance Measurements for the Microsoft Kinect Skeleton

    DTIC Science & Technology

    2012-03-01

    MAR 2012 2. REPORT TYPE 3. DATES COVERED 00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Performance Measurements for the Microsoft Kinect ...8-98) Prescribed by ANSI Std Z39-18 Performance Measurements for the Microsoft Kinect Skeleton Mark A. Livingston∗ Jay Sebastian† Zhuming Ai...Information Inter- faces and Presentation]: User Interfaces—Input devices and strate- gies; 1 INTRODUCTION The Microsoft Kinect for Xbox 360 (“ Kinect

  11. 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…

  12. 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.

  13. 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…

  14. A skeleton family generator via physics-based deformable models.

    PubMed

    Krinidis, Stelios; Chatzis, Vassilios

    2009-01-01

    This paper presents a novel approach for object skeleton family extraction. The introduced technique utilizes a 2-D physics-based deformable model that parameterizes the objects shape. Deformation equations are solved exploiting modal analysis, and proportional to model physical characteristics, a different skeleton is produced every time, generating, in this way, a family of skeletons. The theoretical properties and the experiments presented demonstrate that obtained skeletons match to hand-labeled skeletons provided by human subjects, even in the presence of significant noise and shape variations, cuts and tears, and have the same topology as the original skeletons. In particular, the proposed approach produces no spurious branches without the need of any known skeleton pruning method.

  15. Moderating registration misalignment in voxelwise comparisons of DTI data: a performance evaluation of skeleton projection.

    PubMed

    Zalesky, Andrew

    2011-01-01

    An evaluative methodology and five accompanying performance measures were developed to quantitatively assess the performance of the skeleton projection algorithm constituting the heart of tract-based spatial statistics (TBSS). The performance measures were designed to quantify the accuracy of skeleton projection in its indented task of alleviating any residual misalignment that may remain after image registration. A ground truth fractional anisotropy (FA) image was slightly warped using a realistic warp field that served to model post-registration residual misalignment of varying magnitudes. Skeleton projection was then used to register the warped FA image to the ground truth. Performing skeleton projection was found to yield up to 50% better correspondence between the values of FA compared to smoothing, despite the fact that less than 10% of post-registration misalignment was corrected. The align-max-with-max strategy underlying TBSS was posited as a potential explanation for this high correspondence in the values of FA, at the expense of lesser alignment between anatomically concordant voxels.

  16. 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.

  17. Identification of a membrane skeleton in platelets

    PubMed Central

    1988-01-01

    Platelets have previously been shown to contain actin filaments that are linked, through actin-binding protein, to the glycoprotein (GP) Ib- IX complex, GP Ia, GP IIa, and an unidentified GP of Mr 250,000 on the plasma membrane. The objective of the present study was to use a morphological approach to examine the distribution of these membrane- bound filaments within platelets. Preliminary experiments showed that the Triton X-100 lysis buffers used previously to solubilize platelets completely disrupt the three-dimensional organization of the cytoskeletons. Conditions were established that minimized these postlysis changes. The cytoskeletons remained as platelet-shaped structures. These structures consisted of a network of long actin filaments and a more amorphous layer that outlined the periphery. When Ca2+ was present, the long actin filaments were lost but the amorphous layer at the periphery remained; conditions were established in which this amorphous layer retained the outline of the platelet from which it originated. Immunocytochemical experiments showed that the GP Ib-IX complex and actin-binding protein were associated with the amorphous layer. Analysis of the amorphous material on SDS-polyacrylamide gels showed that it contained actin, actin-binding protein, and all actin- bound GP Ib-IX. Although actin filaments could not be visualized in thin section, the actin presumably was in a filamentous form because it was solubilized by DNase I and bound phalloidin. These studies show that platelets contain a membrane skeleton and suggest that it is distinct from the network of cytoplasmic actin filaments. This membrane skeleton exists as a submembranous lining that, by analogy to the erythrocyte membrane skeleton, may stabilize the plasma membrane and contribute to determining its shape. PMID:3372587

  18. 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.

  19. [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.

  20. Skeleton-Based Abnormal Gait Detection.

    PubMed

    Nguyen, Trong-Nguyen; Huynh, Huu-Hung; Meunier, Jean

    2016-10-26

    Human gait analysis plays an important role in musculoskeletal disorder diagnosis. Detecting anomalies in human walking, such as shuffling gait, stiff leg or unsteady gait, can be difficult if the prior knowledge of such a gait pattern is not available. We propose an approach for detecting abnormal human gait based on a normal gait model. Instead of employing the color image, silhouette, or spatio-temporal volume, our model is created based on human joint positions (skeleton) in time series. We decompose each sequence of normal gait images into gait cycles. Each human instant posture is represented by a feature vector which describes relationships between pairs of bone joints located in the lower body. Such vectors are then converted into codewords using a clustering technique. The normal human gait model is created based on multiple sequences of codewords corresponding to different gait cycles. In the detection stage, a gait cycle with normality likelihood below a threshold, which is determined automatically in the training step, is assumed as an anomaly. The experimental results on both marker-based mocap data and Kinect skeleton show that our method is very promising in distinguishing normal and abnormal gaits with an overall accuracy of 90.12%.

  1. Skeleton-Based Abnormal Gait Detection

    PubMed Central

    Nguyen, Trong-Nguyen; Huynh, Huu-Hung; Meunier, Jean

    2016-01-01

    Human gait analysis plays an important role in musculoskeletal disorder diagnosis. Detecting anomalies in human walking, such as shuffling gait, stiff leg or unsteady gait, can be difficult if the prior knowledge of such a gait pattern is not available. We propose an approach for detecting abnormal human gait based on a normal gait model. Instead of employing the color image, silhouette, or spatio-temporal volume, our model is created based on human joint positions (skeleton) in time series. We decompose each sequence of normal gait images into gait cycles. Each human instant posture is represented by a feature vector which describes relationships between pairs of bone joints located in the lower body. Such vectors are then converted into codewords using a clustering technique. The normal human gait model is created based on multiple sequences of codewords corresponding to different gait cycles. In the detection stage, a gait cycle with normality likelihood below a threshold, which is determined automatically in the training step, is assumed as an anomaly. The experimental results on both marker-based mocap data and Kinect skeleton show that our method is very promising in distinguishing normal and abnormal gaits with an overall accuracy of 90.12%. PMID:27792181

  2. [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.

  3. 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.

  4. Principal Performance Areas and Principal Evaluation.

    ERIC Educational Resources Information Center

    Fletcher, Thomas E.; McInerney, William D.

    1995-01-01

    Summarizes a study that surveyed Indiana superintendents and examined their principal-evaluation instruments. Superintendents were asked which of 21 performance domains were most important and whether these were currently being assessed. Respondents generally agreed that all 21 performance domains identified by the National Policy Board for…

  5. 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…

  6. A Faster, Unbiased Path Opening by Upper Skeletonization and Weighted Adjacency Graphs.

    PubMed

    Asplund, Teo; Luengo Hendriks, Cris L

    2016-12-01

    The path opening is a filter that preserves bright regions in the image in which a path of a certain length L fits. A path is a (not necessarily straight) line defined by a specific adjacency relation. The most efficient implementation known scales as O(min(L, d, Q) N) with the length of the path, L , the maximum possible path length, d , the number of graylevels, Q , and the image size, N . An approximation exists (parsimonious path opening) that has an execution time independent of path length. This is achieved by preselecting paths, and applying 1D openings along these paths. However, the preselected paths can miss important structures, as described by its authors. Here, we propose a different approximation, in which we preselect paths using a grayvalue skeleton. The skeleton follows all ridges in the image, meaning that no important line structures will be missed. An H-minima transform simplifies the image to reduce the number of branches in the skeleton. A graph-based version of the traditional path opening operates only on the pixels in the skeleton, yielding speedups up to one order of magnitude, depending on image size and filter parameters. The edges of the graph are weighted in order to minimize bias. Experiments show that the proposed algorithm scales linearly with image size, and that it is often slightly faster for longer paths than for shorter paths. The algorithm also yields the most accurate results-as compared with a number of path opening variants-when measuring length distributions.

  7. 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.

  8. 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.

  9. 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.

  10. Anterior Cruciate Ligament Injuries in Growing Skeleton

    PubMed Central

    AlHarby, Saleh W.

    2010-01-01

    Anterior cruciate ligament (ACL) injuries in the adult patients are thoroughly studied and published in orthopedic literature. Until recently, little was known about similar injuries in skeletally growing patients. The more frequent involvement of this age group in various athletic activities and the improved diagnostic modalities have increased the awareness and interest of ACL injuries in skeletally immature patients. ACL reconstruction in growing skeleton is controversial and carries some risks to the tibial and femoral growth plate. A guarded approach to ACL reconstruction is recommended in skeletally immature patients. Modification of activity of ACL injured young patient, proper rehabilitation and prudent planning of adolescent age ACL reconstruction carries the least risks of growth plate violation. PMID:21475528

  11. 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

  12. 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.

  13. Performance of skeleton-reinforced biomembranes in locomotion

    NASA Astrophysics Data System (ADS)

    Zhu, Qiang; Shoele, Kourosh

    2008-11-01

    Skeleton-reinforced biomembranes are ubiquitous in nature and play critical roles in many biological functions. Representative examples include insect wings, cell membranes, and mollusk nacres. In this study we focus on the ray fins of fish and investigate the effects of anisotropic flexibility on their performance. Employing a fluid-structure interaction algorithm by coupling a boundary-element model with a nonlinear structural model, we examined the dynamics of a membrane that is geometrically and structurally similar to a caudal fin. Several locomotion modes that closely resemble caudal fin kinematics reported in the literature are applied. Our results show that the flexibility of the fin significantly increases its capacity of thrust generation, manifested as increased efficiency, reduced transverse force, and reduced sensitivity to kinematic parameters. This design also makes the fin more controllable and deployable. Despite simplifications made in this model in terms of fin geometry, internal structure, and kinematics, detailed features of the simulated flow field are consistent with observations and speculations based upon Particle Image Velocimetry (PIV) measurements of flow around live fish.

  14. 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.

  15. 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…

  16. 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…

  17. 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…

  18. 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…

  19. 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…

  20. 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…

  1. 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…

  2. 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

  3. 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.

  4. Giant cell tumors of the axial skeleton.

    PubMed

    Balke, Maurice; Henrichs, Marcel P; Gosheger, Georg; Ahrens, Helmut; Streitbuerger, Arne; Koehler, Michael; Bullmann, Viola; Hardes, Jendrik

    2012-01-01

    Background. We report on 19 cases of giant cell tumor of bone (GCT) affecting the spine or sacrum and evaluate the outcome of different treatment modalities. Methods. Nineteen patients with GCT of the spine (n = 6) or sacrum (n = 13) have been included in this study. The mean followup was 51.6 months. Ten sacral GCT were treated by intralesional procedures of which 4 also received embolization, and 3 with irradiation only. All spinal GCT were surgically treated. Results. Two (15.4%) patients with sacral and 4 (66.7%) with spinal tumors had a local recurrence, two of the letter developed pulmonary metastases. One local recurrence of the spine was successfully treated by serial arterial embolization, a procedure previously described only for sacral tumors. At last followup, 9 patients had no evidence of disease, 8 had stable disease, 1 had progressive disease, 1 died due to disease. Six patients had neurological deficits. Conclusions. GCT of the axial skeleton have a high local recurrence rate. Neurological deficits are common. En-bloc spondylectomy combined with embolization is the treatment of choice. In case of inoperability, serial arterial embolization seems to be an alternative not only for sacral but also for spinal tumors.

  5. Giant Cell Tumors of the Axial Skeleton

    PubMed Central

    Balke, Maurice; Henrichs, Marcel P.; Gosheger, Georg; Ahrens, Helmut; Streitbuerger, Arne; Koehler, Michael; Bullmann, Viola; Hardes, Jendrik

    2012-01-01

    Background. We report on 19 cases of giant cell tumor of bone (GCT) affecting the spine or sacrum and evaluate the outcome of different treatment modalities. Methods. Nineteen patients with GCT of the spine (n = 6) or sacrum (n = 13) have been included in this study. The mean followup was 51.6 months. Ten sacral GCT were treated by intralesional procedures of which 4 also received embolization, and 3 with irradiation only. All spinal GCT were surgically treated. Results. Two (15.4%) patients with sacral and 4 (66.7%) with spinal tumors had a local recurrence, two of the letter developed pulmonary metastases. One local recurrence of the spine was successfully treated by serial arterial embolization, a procedure previously described only for sacral tumors. At last followup, 9 patients had no evidence of disease, 8 had stable disease, 1 had progressive disease, 1 died due to disease. Six patients had neurological deficits. Conclusions. GCT of the axial skeleton have a high local recurrence rate. Neurological deficits are common. En-bloc spondylectomy combined with embolization is the treatment of choice. In case of inoperability, serial arterial embolization seems to be an alternative not only for sacral but also for spinal tumors. PMID:22448122

  6. 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.

  7. Skeleton extraction based on the topology and Snakes model

    NASA Astrophysics Data System (ADS)

    Cai, Yuanxue; Ming, Chengguo; Qin, Yueting

    A new skeleton line extraction method based on topology and flux is proposed by analyzing the distribution characteristics of the gradient vector field in the Snakes model. The distribution characteristics of the skeleton line are accurately obtained by calculating the eigenvalues of the critical points and the flux of the gradient vector field. Then the skeleton lines can be effectively extracted. The results also show that there is no need for the pretreatment or binarization of the target image. The skeleton lines of complex gray images such as optical interference patterns can be effectively extracted by using this method. Compared to traditional methods, this method has many advantages, such as high extraction accuracy and fast processing speed.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Ultrastructure of the intact skeleton of the human erythrocyte membrane.

    PubMed

    Shen, B W; Josephs, R; Steck, T L

    1986-03-01

    Filamentous skeletons were liberated from isolated human erythrocyte membranes in Triton X-100, spread on fenestrated carbon films, negatively stained, and viewed intact and unfixed in the transmission electron microscope. Two forms of the skeleton were examined: (a) basic skeletons, stripped of accessory proteins with 1.5 M NaCl so that they contain predominantly polypeptide bands 1, 2, 4.1, and 5; and (b) unstripped skeletons, which also bore accessory proteins such as ankyrin and band 3 and small plaques of residual lipid. Freshly prepared skeletons were highly condensed. Incubation at low ionic strength and in the presence of dithiothreitol for an hour or more caused an expansion of the skeletons, which greatly increased the visibility of their elements. The expansion may reflect the opening of spectrin from a compact to an elongated disposition. Expanded skeletons appeared to be organized as networks of short actin filaments joined by multiple (5-8) spectrin tetramers. In unstripped preparations, globular masses were observed near the centers of the spectrin filaments, probably corresponding to complexes of ankyrin with band 3 oligomers. Some of these globules linked pairs of spectrin filaments. Skeletons prepared with a minimum of perturbation had thickened actin protofilaments, presumably reflecting the presence of accessory proteins. The length of these actin filaments was highly uniform, averaging 33 +/- 5 nm. This is the length of nonmuscle tropomyosin. Since there is almost enough tropomyosin present to saturate the F-actin, our data support the hypothesis that tropomyosin may determine the length of actin protofilaments in the red cell membrane.

  14. PenPC: A Two-step Approach to Estimate the Skeletons of High Dimensional Directed Acyclic Graphs

    PubMed Central

    Ha, Min Jin; Sun, Wei; Xie, Jichun

    2015-01-01

    Summary Estimation of the skeleton of a directed acyclic graph (DAG) is of great importance for understanding the underlying DAG and causal e ects can be assessed from the skeleton when the DAG is not identifiable. We propose a novel method named PenPC to estimate the skeleton of a high-dimensional DAG by a two-step approach. We first estimate the non-zero entries of a concentration matrix using penalized regression, and then fix the difference between the concentration matrix and the skeleton by evaluating a set of conditional independence hypotheses. For high dimensional problems where the number of vertices p is in polynomial or exponential scale of sample size n, we study the asymptotic property of PenPC on two types of graphs: traditional random graphs where all the vertices have the same expected number of neighbors, and scale-free graphs where a few vertices may have a large number of neighbors. As illustrated by extensive simulations and applications on gene expression data of cancer patients, PenPC has higher sensitivity and specificity than the state-of-the-art method, the PC-stable algorithm. PMID:26406114

  15. 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…

  16. 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…

  17. 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…

  18. The Principal's Legal Handbook.

    ERIC Educational Resources Information Center

    Camp, William E., Ed.; And Others

    The principal is faced with myriad legal issues on a daily basis, making it imperative that he or she keep abreast with developing legal issues. The first of four sections, "Students and the Law," surveys federal statutes and landmark Supreme Court decisions pertaining to the rights of students. It addresses legal issues regarding search and…

  19. Turnaround Principal Competencies

    ERIC Educational Resources Information Center

    Steiner, Lucy; Barrett, Sharon Kebschull

    2012-01-01

    When the Minneapolis Public Schools first set out to hire turnaround school principals, administrators followed their usual process--which focused largely on reputation and anecdotal support and considered mainly internal candidates. Yet success at the complicated task of turning around the fortunes of a failing school depends on exceptionally…

  20. Strategic Principal Communication

    ERIC Educational Resources Information Center

    Henry, Jake; Woody, Aaron

    2013-01-01

    As communities become increasingly diverse and criticism of traditional public schools intensifies, some states, such as North Carolina, have enacted legislation that encourages alternative forms of schooling. This condition has resulted in new challenges for principals to communicate broadly and often with stakeholders in an effort to build…

  1. The Last Angry Principal.

    ERIC Educational Resources Information Center

    Hurwitz, Howard L.

    In March 1976, Howard L. Hurwitz, then a principal in Long Island City Schools, was barricaded in his office by community supporters to prevent him from being fired for an action he took to maintain discipline in the school. This book is Hurwitz's personal account of his subsequent struggles with the New York City schools, including his arrest by…

  2. 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.

  3. 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.

  4. 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

  5. Segmentation and visual analysis of whole-body mouse skeleton microSPECT.

    PubMed

    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 (99m)Tc-methylene diphosphonate ((99m)Tc-MDP) and (99m)Tc-hydroxymethane diphosphonate ((99m)Tc-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

  6. 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.

  7. Structural Perturbations to Population Skeletons: Transient Dynamics, Coexistence of Attractors and the Rarity of Chaos

    PubMed Central

    Singh, Brajendra K.; Parham, Paul E.; Hu, Chin-Kun

    2011-01-01

    Background Simple models of insect populations with non-overlapping generations have been instrumental in understanding the mechanisms behind population cycles, including wild (chaotic) fluctuations. The presence of deterministic chaos in natural populations, however, has never been unequivocally accepted. Recently, it has been proposed that the application of chaos control theory can be useful in unravelling the complexity observed in real population data. This approach is based on structural perturbations to simple population models (population skeletons). The mechanism behind such perturbations to control chaotic dynamics thus far is model dependent and constant (in size and direction) through time. In addition, the outcome of such structurally perturbed models is [almost] always equilibrium type, which fails to commensurate with the patterns observed in population data. Methodology/Principal Findings We present a proportional feedback mechanism that is independent of model formulation and capable of perturbing population skeletons in an evolutionary way, as opposed to requiring constant feedbacks. We observe the same repertoire of patterns, from equilibrium states to non-chaotic aperiodic oscillations to chaotic behaviour, across different population models, in agreement with observations in real population data. Model outputs also indicate the existence of multiple attractors in some parameter regimes and this coexistence is found to depend on initial population densities or the duration of transient dynamics. Our results suggest that such a feedback mechanism may enable a better understanding of the regulatory processes in natural populations. PMID:21980342

  8. Transforming Principal Preparation. ERIC Digest.

    ERIC Educational Resources Information Center

    Lashway, Larry

    In the current climate of accountability, the responsibilities of principals have increased. The new role of principals requires new forms of training, and standards-based reform is generating major changes in principal-preparation programs. This digest examines some of those changes. First, it looks at the effectiveness of principal-preparation…

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Open glenohumeral dislocation: skeletonization of the proximal humerus without associated fracture.

    PubMed

    Maroney, Samuel S; Devinney, D Scott

    2011-11-09

    Shoulder dislocations are common injuries. In the realm of high-energy trauma, enough force can be dissipated to violate the entire soft tissue envelope surrounding the shoulder girdle, generating an open injury. This article presents a case of a young man involved in a motorcycle accident in which he sustained an open glenohumeral dislocation with complete skeletonization of the proximal humerus. There were no associated fractures with his injury. Our patient underwent staged irrigation and debridement of his shoulder with delayed tendoligamentous reconstruction of the skeletonized proximal humerus. After reconstruction, he was immobilized for 3 weeks and then began a progressive shoulder rehabilitation protocol. He healed with no evidence of infection, residual instability, or avascular necrosis at his 4-month follow-up examination. At that point, he had regained functional use of his shoulder for activities of daily living and had no pain. His range of active motion was limited to 90° of flexion and abduction, 0° of external rotation, and internal rotation to the L4. He had complete resolution of a sensory and motor axillary neuropraxia that resulted from his initial injury. It was felt that the patient had potential for continued gains in range of motion and strength.Our patient is only the second description of an open glenohumeral dislocation with no associated fractures of the proximal humerus. This skeletonization of the proximal humerus represents a complex soft tissue injury that severely compromises the functional capacity of the shoulder. Understanding the nature of the injury and the involved structures and maintaining a sound treatment algorithm allow orthopedic surgeons to maximize the patient's functional outcome.

  15. 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

  16. Recursive principal components analysis.

    PubMed

    Voegtlin, Thomas

    2005-10-01

    A recurrent linear network can be trained with Oja's constrained Hebbian learning rule. As a result, the network learns to represent the temporal context associated to its input sequence. The operation performed by the network is a generalization of Principal Components Analysis (PCA) to time-series, called Recursive PCA. The representations learned by the network are adapted to the temporal statistics of the input. Moreover, sequences stored in the network may be retrieved explicitly, in the reverse order of presentation, thus providing a straight-forward neural implementation of a logical stack.

  17. A practical introduction to skeletons for the plant sciences.

    PubMed

    Bucksch, Alexander

    2014-08-01

    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.

  18. 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

  19. 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.…

  20. Bone density and the lightweight skeletons of birds.

    PubMed

    Dumont, Elizabeth R

    2010-07-22

    The skeletons of birds are universally described as lightweight as a result of selection for minimizing the energy required for flight. From a functional perspective, the weight (mass) of an animal relative to its lift-generating surfaces is a key determinant of the metabolic cost of flight. The evolution of birds has been characterized by many weight-saving adaptations that are reflected in bone shape, many of which strengthen and stiffen the skeleton. Although largely unstudied in birds, the material properties of bone tissue can also contribute to bone strength and stiffness. In this study, I calculated the density of the cranium, humerus and femur in passerine birds, rodents and bats by measuring bone mass and volume using helium displacement. I found that, on average, these bones are densest in birds, followed closely by bats. As bone density increases, so do bone stiffness and strength. Both of these optimization criteria are used in the design of strong and stiff, but lightweight, manmade airframes. By analogy, increased bone density in birds and bats may reflect adaptations for maximizing bone strength and stiffness while minimizing bone mass and volume. These data suggest that both bone shape and the material properties of bone tissue have played important roles in the evolution of flight. They also reconcile the conundrum of how bird skeletons can appear to be thin and delicate, yet contribute just as much to total body mass as do the skeletons of terrestrial mammals.

  1. 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.

  2. 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.

  3. Principal Preferences and the Uneven Distribution of Principals across Schools

    ERIC Educational Resources Information Center

    Loeb, Susanna; Kalogrides, Demetra; Horng, Eileen Lai

    2010-01-01

    The authors use longitudinal data from one large school district to investigate the distribution of principals across schools. They find that schools serving many low-income, non-White, and low-achieving students have principals who have less experience and less education and who attended less selective colleges. This distribution of principals is…

  4. 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…

  5. 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…

  6. 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…

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. Visualization of the hexagonal lattice in the erythrocyte membrane skeleton.

    PubMed

    Liu, S C; Derick, L H; Palek, J

    1987-03-01

    The isolated membrane skeleton of human erythrocytes was studied by high resolution negative staining electron microscopy. When the skeletal meshwork is spread onto a thin carbon film, clear images of a primarily hexagonal lattice of junctional F-actin complexes crosslinked by spectrin filaments are obtained. The regularly ordered network extends over the entire membrane skeleton. Some of the junctional complexes are arranged in the form of pentagons and septagons, approximately 3 and 8%, respectively. At least five forms of spectrin crosslinks are detected in the spread skeleton including a single spectrin tetramer linking two junctional complexes, three-armed Y-shaped spectrin molecules linking three junctional complexes, three-armed spectrin molecules connecting two junctional complexes with two arms bound to one complex and the third arm bound to the adjacent complex, double spectrin filaments linking two junctional complexes, and four-armed spectrin molecules linking two junctional complexes. Of these, the crosslinks of single spectrin tetramers and three-armed molecules are the most abundant and represent 84 and 11% of the total crosslinks, respectively. These observations are compatible with the presence of spectrin tetramers and oligomers in the erythrocyte membrane skeleton. Globular structures (9-12 nm in diameter) are attached to the majority of the spectrin tetramers or higher order oligomer-like molecules, approximately 80 nm from the distal ends of the spectrin tetramers. These globular structures are ankyrinor ankyrin/band 3-containing complexes, since they are absent when ankyrin and residual band 3 are extracted from the skeleton under hypertonic conditions.

  12. 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)

  13. In vitro quantification of strain patterns in the craniofacial skeleton due to masseter and temporalis activities.

    PubMed

    Maloul, Asmaa; Regev, Eran; Whyne, Cari M; Beek, Marteen; Fialkov, Jeffrey A

    2012-09-01

    Many complications in craniofacial surgery can be attributed to a lack of characterization of facial skeletal strain patterns. This study aimed to delineate human midfacial strain patterns under uniform muscle loading. The left sides of 5 fresh-frozen human cadaveric heads were dissected of all soft tissues except the temporalis and masseter muscles. Tensile forces were applied to the free mandibular ends of the muscles. Maxillary alveolar arches were used to restrain the skulls. Eight strain gauges were bonded to the surface of the midface to measure the strain under single muscle loading conditions (100 N). Maxillary strain gauges revealed a biaxial load state for both muscles. Thin antral bone experienced high maximum principal tensile strains (maximum of 685.5 με) and high minimum principal compressive strains (maximum of -722.44 με). Similar biaxial patterns of lower magnitude were measured on the zygoma (maximum of 208.59 με for maximum principal strains and -78.11 με for minimum principal strains). Results, consistent for all specimens and counter to previously accepted concepts of biomechanical behavior of the midface under masticatory muscle loading, included high strain in the thin maxillary antral wall, rotational bending through the maxilla and zygoma, and a previously underestimated contribution of the temporalis muscle. This experimental model produced repeatable strain patterns quantifying the mechanics of the facial skeleton. These new counterintuitive findings underscore the need for accurate characterization of craniofacial strain patterns to address problems in the current treatment methods and develop robust design criteria.

  14. The Principal as White Knight.

    ERIC Educational Resources Information Center

    Stanfield, Pamela C.; Walter, James E.

    This 20-month study describes an elementary school principal, John Meyer, and examines his leadership behaviors. From an effective schools perspective, the principal is seen as the white knight who "saves" the children by providing an effective school. John Meyer is known as a "turnaround" principal who came to Garvin School (located in a Missouri…

  15. Principals' Relationship with Computer Technology

    ERIC Educational Resources Information Center

    Brockmeier, Lantry L.; Sermon, Janet M.; Hope, Warren C.

    2005-01-01

    This investigation sought information about principals and their relationship with computer technology. Several questions were fundamental to the inquiry. Are principals prepared to facilitate the attainment of technology's promise through the integration of computer technology into the teaching and learning process? Are principals prepared to use…

  16. 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…

  17. Principal Succession: A Case Study.

    ERIC Educational Resources Information Center

    Jones, Jeffery C.; Webber, Charles F.

    Principal succession is misunderstood and underutilized as a means of affecting dynamic renewal in school communities. Previously, the replacement of a principal was examined solely through the experiences of principals and teachers. This paper reports on a case study that added the previously neglected perspectives of students, support staff, and…

  18. Emerging Challenges Facing School Principals

    ERIC Educational Resources Information Center

    Wise, Donald

    2015-01-01

    This article provides insights into the challenges facing US public school principals. A survey was sent to a random sample of over 10,000 principals throughout the US. Written responses from a representative sample were analyzed for content and themes. Results indicate that principals are facing emerging challenges never before seen in education,…

  19. School Principals' Emotional Coping Process

    ERIC Educational Resources Information Center

    Poirel, Emmanuel; Yvon, Frédéric

    2014-01-01

    The present study examines the emotional coping of school principals in Quebec. Emotional coping was measured by stimulated recall; six principals were filmed during a working day and presented a week later with their video showing stressful encounters. The results show that school principals experience anger because of reproaches from staff…

  20. Principals' Salaries, 2008-2009

    ERIC Educational Resources Information Center

    Cooke, Willa D.; Licciardi, Chris

    2009-01-01

    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? There are reliable…

  1. Principals' Salaries, 2007-2008

    ERIC Educational Resources Information Center

    Cooke, Willa D.; Licciardi, Chris

    2008-01-01

    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? There are reliable…

  2. 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…

  3. 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.

  4. 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.

  5. Brief communication: "Zuzu" strikes again--morphological affinities of the early holocene human skeleton from Toca dos Coqueiros, Piaui, Brazil.

    PubMed

    Hubbe, Mark; Neves, Walter A; do Amaral, Heleno Licurgo; Guidon, Niéde

    2007-10-01

    The Serra da Capivara National Park in northeastern Brazil is one of the richest archaeological regions in South America. Nonetheless, so far only two paleoindian skeletons have been exhumed from the local rockshelters. The oldest one (9870 +/- 50 BP; CAL 11060 +/- 50), uncovered in Toca dos Coqueiros and known as "Zuzu," represents a rare opportunity to explore the biological relationships of paleoindian groups living in northeastern Brazil. As previously demonstrated, South and Central America Paleoindians present skull morphology distinct from the one found nowadays in Amerindians and similar to Australo-Melanesians. Here we test the hypothesis that Zuzu shows higher morphological affinity with Paleoindians. However, Zuzu is a controversial skeleton since previous osteological assessments have disagreed on several aspects, especially regarding its sex. Thus, we compared Zuzu to males and females independently. Morphological affinities were assessed through clustering of principal components considering 18 worldwide populations and through principal components analysis of the individual dispersion of five key regions for America's settlement. The results obtained do not allow us to refute the hypothesis, expanding the known geographical dispersion of the Paleoindian morphology into northeast Brazil. To contribute to the discussion regarding Zuzu's sex, a new estimation is presented based on visual inspection of cranial and post-cranial markers, complemented by a discriminant analysis of its morphology in relation to the paleoindian sample. The results favor a male classification and are consistent with the mortuary offerings found in the burial, yet do not agree with a molecular determination.

  6. 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

  7. 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…

  8. 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.

  9. Aneurysm identification by analysis of the blood-vessel skeleton.

    PubMed

    Kohout, Josef; Chiarini, Alessandro; Clapworthy, Gordon J; Klajnšek, Gregor

    2013-01-01

    At least 1% of the general population have an aneurysm (or possibly more) in their cerebral blood vessels. If an aneurysm ruptures, it kills the patient in up to 60% of cases. In order to choose the optimal treatment, clinicians have to monitor the development of the aneurysm in time. Nowadays, aneurysms are typically identified manually, which means that the monitoring is often imprecise since the identification is observer dependent. As a result, the number of misdiagnosed cases may be large. This paper proposes a fast semi-automatic method for the identification of aneurysms which is based on the analysis of the skeleton of blood vessels. Provided that the skeleton is accurate, the results achieved by our method have been deemed acceptable by expert clinicians.

  10. 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…

  11. A new conceptual model of the formation of coral skeleton

    NASA Astrophysics Data System (ADS)

    Juillet-Leclerc, A.

    2006-12-01

    Scleractinian corals constitute one of the major groups of calcifying animals. During a long time their skeleton has been considered as purely mineral and all the features not consistent with this concept were called " vital effects ". However, biology plays a key role in the skeleton genesis. Recent technological advances provided enough evidences to propose a new conceptual model of coral skeleton growth. Ion microprobe carried out both trace element and isotope analyses, which stressed the high variability of these geochemical tracers. It indicates that all measurements obtained at millimeter-length scale, especially data used for paleoclimatic purpose, are bulk data. The analyses performed on individual microstructures previously identified by SEMS observation revealed that the two different microstructures highlighted in coral skeleton present a specific geochemical signature. We have thus to explain how two specific microstructures could derive from a unique calcifying fluid. On the other hand, several methods converged to show that a thin organic matrix surrounds growth units at micro/nanometer size scale. The presence of organic compounds could alter the equilibrium thermodynamics of the mineral growth surface by modifying energy landscape. Knowing that chemical environment of each microstructure could be different according the nature of the growth units we assume that it induces different mechanism of deposition. By combining results from different approaches we deduce that kinetics is not restricted to isotopic fractionation. We conclude that coral aragonite deposit is dominated by a kinetic chemical disequilibrium and governed by supersaturation law. We demonstrate that this conceptual model is consistent with the observations and measurements earlier performed and coral remains the most relevant archive of the tropical ocean than ever.

  12. The Minotaur syndrome: plastic surgery of the facial skeleton.

    PubMed

    Morselli, P G

    1993-01-01

    This article remarks on the possibility of recontouring the face by working on the facial skeleton with the sole purpose of softening the facial appearance. The author describes a one-step surgical procedure performed on a 38-year-old man who had serious social problems because of his aggressive and threatening facial appearance that contrasted with his gentle personality. The author coins the term Minotaur Syndrome to describe the discrepancy between the patient's true personality versus his negative facial appearance.

  13. Efficient synthesis of a multi-substituted diphenylmethane skeleton as a steroid mimetic.

    PubMed

    Misawa, Takashi; Tanaka, Katsuya; Demizu, Yosuke; Kurihara, Masaaki

    2017-03-24

    Steroids are important components of cell membranes and are involved in several physiological functions. A diphenylmethane (DPM) skeleton has recently been suggested to act as a mimetic of the steroid skeleton. However, difficulties are associated with efficiently introducing different substituents between two phenyl rings of the DPM skeleton, and, thus, further structural development based on the DPM skeleton has been limited. We herein developed an efficient synthetic method for introducing different substituents into two phenyl rings of the DPM skeleton. We also synthesized DPM-based estrogen receptor (ER) modulators using our synthetic method and evaluated their ER transcriptional activities.

  14. 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.

  15. Morphological integration versus ecological plasticity in the avian pelvic limb skeleton.

    PubMed

    Stoessel, Alexander; Kilbourne, Brandon M; Fischer, Martin S

    2013-05-01

    Understanding patterns and distributions of morphological traits is essential for discerning underpinning processes of morphological variation. We report on the variation in the avian pelvic limb skeleton. Length and width variables were measured in the skeletons of 236 avian species in order to examine the importance of body mass, ecological factors, phylogeny and integration in the formation of specific hindlimb morphology. Scaling relationships with body mass were analyzed across Aves and in individual avian subclades. Principal component analysis and multiple regressions were performed to examine the relationship between morphology, ecology, and phylogeny. Finally, the occurrence of within-limb morphological integration was tested by partial correlation analysis of the residuals from element lengths vs. body mass and correlation analysis of avian hindlimb proportions. Body mass is the greatest contributor to variation, and it strongly influences variation in avian skeletal lengths. Lengthening of the leg typically comes from disproportionate increases in tibiotarsal and tarsometatarsal length. Partial correlation analysis showed that only these two elements are distinctly integrated consistently across all bird taxa, whereas relation of femur and third toe to other limb elements displays no clear pattern. Hence, morphological integration of all elements is not a prerequisite for limb design, and variation between taxa is mainly to be found in femoral and digital length. Furthermore, variation in tibiotarsal relative length is much lower than in other elements likely due to geometric constrains. Clear ecological adaptations are obscured by multifunctionality of the avian hindlimb, and phylogeny significantly constrains the morphology. Finally, when looking at relative lengths segmented limbs meet the requirements of many-to-one-mapping of phenotype to functional property, in line with a common concept of evolvability of function and morphology.

  16. 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.

  17. 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

  18. 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

  19. Linear measurements of the neurocranium are better indicators of population differences than those of the facial skeleton: comparative study of 1,961 skulls.

    PubMed

    Holló, Gábor; Szathmáry, László; Marcsik, Antónia; Barta, Zoltán

    2010-02-01

    The aim of this study is to individualize potential differences between two cranial regions used to differentiate human populations. We compared the neurocranium and the facial skeleton using skulls from the Great Hungarian Plain. The skulls date to the 1st-11th centuries, a long space of time that encompasses seven archaeological periods. We analyzed six neurocranial and seven facial measurements. The reduction of the number of variables was carried out using principal components analysis. Linear mixed-effects models were fitted to the principal components of each archaeological period, and then the models were compared using multiple pairwise tests. The neurocranium showed significant differences in seven cases between nonsubsequent periods and in one case, between two subsequent populations. For the facial skeleton, no significant results were found. Our results, which are also compared to previous craniofacial heritability estimates, suggest that the neurocranium is a more conservative region and that population differences can be pointed out better in the neurocranium than in the facial skeleton.

  20. 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)

  1. Principals' Leadership Network. Focusing on the Image of the Principal

    ERIC Educational Resources Information Center

    Newby, Cheryl Riggins; Hayden, Hal

    2004-01-01

    A recent study by The National Association of Elementary School Principals (NAESP), Principals in the Public: Engaging Community Support (2000) found that communication, marketing, public affairs and public relations and engagement activities are now given more time and importance than ever before. According to the study, public support builds…

  2. 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…

  3. Bayesian principal geodesic analysis for estimating intrinsic diffeomorphic image variability.

    PubMed

    Zhang, Miaomiao; Fletcher, P Thomas

    2015-10-01

    In this paper, we present a generative Bayesian approach for estimating the low-dimensional latent space of diffeomorphic shape variability in a population of images. We develop a latent variable model for principal geodesic analysis (PGA) that provides a probabilistic framework for factor analysis in the space of diffeomorphisms. A sparsity prior in the model results in automatic selection of the number of relevant dimensions by driving unnecessary principal geodesics to zero. To infer model parameters, including the image atlas, principal geodesic deformations, and the effective dimensionality, we introduce an expectation maximization (EM) algorithm. We evaluate our proposed model on 2D synthetic data and the 3D OASIS brain database of magnetic resonance images, and show that the automatically selected latent dimensions from our model are able to reconstruct unobserved testing images with lower error than both linear principal component analysis (LPCA) in the image space and tangent space principal component analysis (TPCA) in the diffeomorphism space.

  4. 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…

  5. 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…

  6. 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…

  7. 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…

  8. 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…

  9. 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…

  10. The Principal as Formative Coach

    ERIC Educational Resources Information Center

    Nidus, Gabrielle; Sadder, Maya

    2011-01-01

    Formative coaching, an approach that uses student work as the foundation for mentoring and professional development, can help principals become more effective instructional leaders. In formative coaching, teaches and coaches analyze student work to determine next steps for instruction. This article shows how a principal can use the steps of the…

  11. 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…

  12. 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…

  13. Preparing for Your Principal Interview

    ERIC Educational Resources Information Center

    Spanneut, Gene

    2007-01-01

    Being invited to the initial round of interviews for a principal opening is an opportunity; preparing for it is an investment. A successful interview requires that you create a detailed plan and take specific steps. This article provides tips on how to prepare yourself for a principal interview. Before you focus on what to do during your…

  14. 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…

  15. The Principal and Human Relations.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh. Div. of Human Relations.

    This booklet offers general guidelines and recommendations on how to develop and exercise the interpersonal skills required of a successful school principal. Attention is devoted to the basic principles of effective communication and personal interaction, with emphasis on the principal's relations with students, teachers, and members of the…

  16. 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…

  17. Complex principal components for robust motion estimation.

    PubMed

    Mauldin, F William; Viola, Francesco; Walker, William F

    2010-11-01

    Bias and variance errors in motion estimation result from electronic noise, decorrelation, aliasing, and inherent algorithm limitations. Unlike most error sources, decorrelation is coherent over time and has the same power spectrum as the signal. Thus, reducing decorrelation is impossible through frequency domain filtering or simple averaging and must be achieved through other methods. In this paper, we present a novel motion estimator, termed the principal component displacement estimator (PCDE), which takes advantage of the signal separation capabilities of principal component analysis (PCA) to reject decorrelation and noise. Furthermore, PCDE only requires the computation of a single principal component, enabling computational speed that is on the same order of magnitude or faster than the commonly used Loupas algorithm. Unlike prior PCA strategies, PCDE uses complex data to generate motion estimates using only a single principal component. The use of complex echo data is critical because it allows for separation of signal components based on motion, which is revealed through phase changes of the complex principal components. PCDE operates on the assumption that the signal component of interest is also the most energetic component in an ensemble of echo data. This assumption holds in most clinical ultrasound environments. However, in environments where electronic noise SNR is less than 0 dB or in blood flow data for which the wall signal dominates the signal from blood flow, the calculation of more than one PC is required to obtain the signal of interest. We simulated synthetic ultrasound data to assess the performance of PCDE over a wide range of imaging conditions and in the presence of decorrelation and additive noise. Under typical ultrasonic elasticity imaging conditions (0.98 signal correlation, 25 dB SNR, 1 sample shift), PCDE decreased estimation bias by more than 10% and standard deviation by more than 30% compared with the Loupas method and normalized

  18. The integumentary skeleton of tetrapods: origin, evolution, and development

    PubMed Central

    Vickaryous, Matthew K; Sire, Jean-Yves

    2009-01-01

    Although often overlooked, the integument of many tetrapods is reinforced by a morphologically and structurally diverse assemblage of skeletal elements. These elements are widely understood to be derivatives of the once all-encompassing dermal skeleton of stem-gnathostomes but most details of their evolution and development remain confused and uncertain. Herein we re-evaluate the tetrapod integumentary skeleton by integrating comparative developmental and tissue structure data. Three types of tetrapod integumentary elements are recognized: (1) osteoderms, common to representatives of most major taxonomic lineages; (2) dermal scales, unique to gymnophionans; and (3) the lamina calcarea, an enigmatic tissue found only in some anurans. As presently understood, all are derivatives of the ancestral cosmoid scale and all originate from scleroblastic neural crest cells. Osteoderms are plesiomorphic for tetrapods but demonstrate considerable lineage-specific variability in size, shape, and tissue structure and composition. While metaplastic ossification often plays a role in osteoderm development, it is not the exclusive mode of skeletogenesis. All osteoderms share a common origin within the dermis (at or adjacent to the stratum superficiale) and are composed primarily (but not exclusively) of osseous tissue. These data support the notion that all osteoderms are derivatives of a neural crest-derived osteogenic cell population (with possible matrix contributions from the overlying epidermis) and share a deep homology associated with the skeletogenic competence of the dermis. Gymnophionan dermal scales are structurally similar to the elasmoid scales of most teleosts and are not comparable with osteoderms. Whereas details of development are lacking, it is hypothesized that dermal scales are derivatives of an odontogenic neural crest cell population and that skeletogenesis is comparable with the formation of elasmoid scales. Little is known about the lamina calcarea. It is

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Synthesis of the Acyclic Carbon Skeleton of Filipin III.

    PubMed

    Brun, Elodie; Bellosta, Véronique; Cossy, Janine

    2016-09-16

    The synthesis of the carbon skeleton of filipin III, a polyenic macrolactone possessing 11 stereogenic centers, was achieved using a convergent strategy with the longest linear sequence of 19 steps starting from hexanal. Construction of the polyene was realized using two successive Heck couplings as the key steps. Control of the stereogenic centers of the polyol fragment was performed by utilizing an Evans aldolization, a 1,3-syn aldolization, enantio- and diastereoselective allylations, a hemiacetalization/oxa-Michael sequence, and a 1,3-syn reduction. The polyol and polyenic fragments were coupled using a 1,5-anti diastereoselective aldolization followed by a 1,3-anti reduction.

  4. Bioactive acylphloroglucinols with adamantyl skeleton from Hypericum sampsonii.

    PubMed

    Zhu, Hucheng; Chen, Chunmei; Yang, Jing; Li, Xiao-Nian; Liu, Junjun; Sun, Bin; Huang, Sheng-Xiong; Li, Dongyan; Yao, Guangmin; Luo, Zengwei; Li, Yan; Zhang, Jinwen; Xue, Yongbo; Zhang, Yonghui

    2014-12-19

    Hyperisampsins A-D (1-4), with tetracyclo[6.3.1.1(3,10).0(3,7)]tridecane skeletons and seven biogenetically related congeners (5-11), were isolated from Hypericum sampsonii. Their structures were elucidated by comprehensive spectroscopic techniques. The absolute configuration of 1 was established by ECD calculations, and those of 5 and 9 were confirmed by single X-ray crystallographic analyses. Hyperisampsins A and D showed potent anti-HIV activities with EC50 of 2.97 and 0.97 μM and selectivity index of 4.80 and 7.70, respectively.

  5. [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

  6. p-Coumaric acid - a monomer in the sporopollenin skeleton.

    PubMed

    Wehling, K; Niester, C; Boon, J J; Willemse, M T; Wiermann, R

    1989-10-01

    Sporopollenin obtained from wings of Pinus mugo (Turra) pollen was analysed by pyrolysis mass spectrometry. In the spectrum, mass peaks which are characteristic for p-coumaric acid were dominant. p-Coumaric acid was the main degradation compound when the wing material was treated by a gentle method using AII3, and also when the remaining residue of the treated sporopollenin material was saponified. It is therefore assumed that p-coumaric acid is a genuine structural unit in the sporopollenin skeleton. In addition, the effects of AII3 treatment indicate that the p-coumaric acid might be bound by ether linkages.

  7. 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.

  8. 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.

  9. Incremental principal component pursuit for video background modeling

    DOEpatents

    Rodriquez-Valderrama, Paul A.; Wohlberg, Brendt

    2017-03-14

    An incremental Principal Component Pursuit (PCP) algorithm for video background modeling that is able to process one frame at a time while adapting to changes in background, with a computational complexity that allows for real-time processing, having a low memory footprint and is robust to translational and rotational jitter.

  10. 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)

  11. Genetic analysis of 7 medieval skeletons from Aragonese Pyrenees

    PubMed Central

    Núńez, Carolina; Sosa, Cecilia; Baeta, Miriam; Geppert, Maria; Turnbough, Meredith; Phillips, Nicole; Casalod, Yolanda; Bolea, Miguel; Roby, Rhonda; Budowle, Bruce; Martínez-Jarreta, Begońa

    2011-01-01

    Aim To perform a genetic characterization of 7 skeletons from medieval age found in a burial site in the Aragonese Pyrenees. Methods Allele frequencies of autosomal short tandem repeats (STR) loci were determined by 3 different STR systems. Mitochondrial DNA (mtDNA) and Y-chromosome haplogroups were determined by sequencing of the hypervariable segment 1 of mtDNA and typing of phylogenetic Y chromosome single nucleotide polymorphisms (Y-SNP) markers, respectively. Possible familial relationships were also investigated. Results Complete or partial STR profiles were obtained in 3 of the 7 samples. Mitochondrial DNA haplogroup was determined in 6 samples, with 5 of them corresponding to the haplogroup H and 1 to the haplogroup U5a. Y-chromosome haplogroup was determined in 2 samples, corresponding to the haplogroup R. In one of them, the sub-branch R1b1b2 was determined. mtDNA sequences indicated that some of the individuals could be maternally related, while STR profiles indicated no direct family relationships. Conclusions Despite the antiquity of the samples and great difficulty that genetic analyses entail, the combined use of autosomal STR markers, Y-chromosome informative SNPs, and mtDNA sequences allowed us to genotype a group of skeletons from the medieval age. PMID:21674829

  12. 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.

  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. 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.

  15. Minimum convex hull mass estimations of complete mounted skeletons.

    PubMed

    Sellers, W I; Hepworth-Bell, J; Falkingham, P L; Bates, K T; Brassey, C A; Egerton, V M; Manning, P L

    2012-10-23

    Body mass is a critical parameter used to constrain biomechanical and physiological traits of organisms. Volumetric methods are becoming more common as techniques for estimating the body masses of fossil vertebrates. However, they are often accused of excessive subjective input when estimating the thickness of missing soft tissue. Here, we demonstrate an alternative approach where a minimum convex hull is derived mathematically from the point cloud generated by laser-scanning mounted skeletons. This has the advantage of requiring minimal user intervention and is thus more objective and far quicker. We test this method on 14 relatively large-bodied mammalian skeletons and demonstrate that it consistently underestimates body mass by 21 per cent with minimal scatter around the regression line. We therefore suggest that it is a robust method of estimating body mass where a mounted skeletal reconstruction is available and demonstrate its usage to predict the body mass of one of the largest, relatively complete sauropod dinosaurs: Giraffatitan brancai (previously Brachiosaurus) as 23200 kg.

  16. The origin of conodonts and of vertebrate mineralized skeletons.

    PubMed

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

    2013-10-24

    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.

  17. 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.

  18. 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.

  19. 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.

  20. Minimum convex hull mass estimations of complete mounted skeletons

    PubMed Central

    Sellers, W. I.; Hepworth-Bell, J.; Falkingham, P. L.; Bates, K. T.; Brassey, C. A.; Egerton, V. M.; Manning, P. L.

    2012-01-01

    Body mass is a critical parameter used to constrain biomechanical and physiological traits of organisms. Volumetric methods are becoming more common as techniques for estimating the body masses of fossil vertebrates. However, they are often accused of excessive subjective input when estimating the thickness of missing soft tissue. Here, we demonstrate an alternative approach where a minimum convex hull is derived mathematically from the point cloud generated by laser-scanning mounted skeletons. This has the advantage of requiring minimal user intervention and is thus more objective and far quicker. We test this method on 14 relatively large-bodied mammalian skeletons and demonstrate that it consistently underestimates body mass by 21 per cent with minimal scatter around the regression line. We therefore suggest that it is a robust method of estimating body mass where a mounted skeletal reconstruction is available and demonstrate its usage to predict the body mass of one of the largest, relatively complete sauropod dinosaurs: Giraffatitan brancai (previously Brachiosaurus) as 23200 kg. PMID:22675141

  1. Principal Fibrations from Noncommutative Spheres

    NASA Astrophysics Data System (ADS)

    Landi, Giovanni; Suijlekom, Walter Van

    2005-11-01

    We construct noncommutative principal fibrations Sθ7→Sθ4 which are deformations of the classical SU(2) Hopf fibration over the four sphere. We realize the noncommutative vector bundles associated to the irreducible representations of SU(2) as modules of coequivariant maps and construct corresponding projections. The index of Dirac operators with coefficients in the associated bundles is computed with the Connes-Moscovici local index formula. "The algebra inclusion is an example of a not-trivial quantum principal bundle."

  2. Evolutionary exploitation of design options by the first animals with hard skeletons.

    PubMed

    Thomas, R D; Shearman, R M; Stewart, G W

    2000-05-19

    The set of viable design elements available for animals to use in building skeletons has been fully exploited. Analysis of animal skeletons in relation to the multivariate, theoretical "Skeleton Space" has shown that a large proportion of these options are used in each phylum. Here, we show that structural elements deployed in the skeletons of Burgess Shale animals (Middle Cambrian) incorporate 146 of 182 character pairs defined in this morphospace. Within 15 million years of the appearance of crown groups of phyla with substantial hard parts, at least 80 percent of skeletal design elements recognized among living and extinct marine metazoans were exploited.

  3. PRINCIPAL COMPONENTS FOR NON-LOCAL MEANS IMAGE DENOISING.

    PubMed

    Tasdizen, Tolga

    2008-01-01

    This paper presents an image denoising algorithm that uses principal component analysis (PCA) in conjunction with the non-local means image denoising. Image neighborhood vectors used in the non-local means algorithm are first projected onto a lower-dimensional subspace using PCA. Consequently, neighborhood similarity weights for denoising are computed using distances in this subspace rather than the full space. This modification to the non-local means algorithm results in improved accuracy and computational performance. We present an analysis of the proposed method's accuracy as a function of the dimensionality of the projection subspace and demonstrate that denoising accuracy peaks at a relatively low number of dimensions.

  4. Visualization of the Protein Associations in the Erythrocyte Membrane Skeleton

    NASA Astrophysics Data System (ADS)

    Byers, Timothy J.; Branton, Daniel

    1985-09-01

    We have obtained clear images of the erythrocyte membrane skeleton from negatively stained preparations that originate directly from the intact cell but in which the spectrin meshwork is artificially spread to allow close inspection. Our procedure requires less than 2 min at 5 degrees C in phosphate buffers. We find 200-nm-long spectrin tetramers crosslinked by junctional complexes. Each junction contains a regular 37-nm rod, probably an actin oligomer of approximately 13 monomers. Densities appear at variable places in the meshwork but distinct globules occur with great frequency 78 nm from the spectrin tetramer's junctional insertion end, very close to the known binding site for ankyrin. Most frequently, five or six spectrin tetramers insert into each junction, producing a meshwork that displays remarkably regular long range order.

  5. Regulation of energy metabolism by the skeleton: osteocalcin and beyond.

    PubMed

    Ferron, Mathieu; Lacombe, Julie

    2014-11-01

    The skeleton has recently emerged as an endocrine organ implicated in the regulation of glucose and energy metabolism. This function of bone is mediated, at least in part, by osteocalcin, an osteoblast-derived protein acting as a hormone stimulating insulin sensitivity, insulin secretion and energy expenditure. Osteocalcin secretion and bioactivity is in turn regulated by several hormonal cues including insulin, leptin, the sympathetic nervous system and glucocorticoids. Recent findings support the notion that osteocalcin functions and regulations are conserved between mice and humans. Moreover, studies in mice suggest that osteocalcin could represent a viable therapeutic approach for the treatment of obesity and insulin resistance. In this review, we summarize the current knowledge on osteocalcin functions, its various modes of action and the mechanisms implicated in the control of this hormone.

  6. Novel nonsecosteroidal VDR agonists with phenyl-pyrrolyl pentane skeleton.

    PubMed

    Shen, Wei; Xue, Jingwei; Zhao, Zekai; Zhang, Can

    2013-11-01

    In order to find the vitamin D receptor (VDR) ligand whose VDR agonistic activity is separated from the calcemic activity sufficiently, novel nonsecosteroidal analogs with phenyl-pyrrolyl pentane skeleton were synthesized and evaluated for the VDR binding affinity, antiproliferative activity in vitro and serum calcium raising ability in vivo (tacalcitol used as control). Among them, several compounds showed varying degrees of VDR agonistic and growth inhibition activities of the tested cell lines. The most effective compound 2g (EC₅₀: 1.06 nM) exhibited stronger VDR agonistic activity than tacalcitol (EC₅₀: 7.05 nM), inhibited the proliferations of HaCaT and MCF-7 cells with IC₅₀ of 2.06 μM and 0.307 μM (tacalcitol: 2.07 μM and 0.057 μM) and showed no significant effect on serum calcium.

  7. 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.

  8. 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.

  9. Mineralized cartilage in the skeleton of chondrichthyan fishes.

    PubMed

    Dean, Mason N; Summers, Adam P

    2006-01-01

    The cartilaginous endoskeleton of chondrichthyan fishes (sharks, rays, and chimaeras) exhibits complex arrangements and morphologies of calcified tissues that vary with age, species, feeding behavior, and location in the body. Understanding of the development, evolutionary history and function of these tissue types has been hampered by the lack of a unifying terminology. In order to facilitate reciprocal illumination between disparate fields with convergent interests, we present levels of organization in which crystal orientation/size delimits three calcification types (areolar, globular, and prismatic) that interact in two distinct skeletal types, vertebral and tessellated cartilage. The tessellated skeleton is composed of small blocks (tesserae) of calcified cartilage (both prismatic and globular) overlying a core of unmineralized cartilage, while vertebral cartilage usually contains all three types of calcification.

  10. 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

  11. 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.

  12. 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

    2013-06-06

    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.

  13. Endocrine regulation of male fertility by the skeleton

    PubMed Central

    Oury, Franck; Sumara, Grzegorz; Sumara, Olga; Ferron, Mathieu; Chang, Haixin; Smith, Charles E.; Hermo, Louis; Suarez, Susan; Roth, Bryan L.; Ducy, Patricia; Karsenty, Gerard

    2011-01-01

    Although the endocrine capacity of bone is widely recognized, interactions between bone and the reproductive system have until now focused on the gonads as a regulator of bone remodeling. We now show that in males, bone acts as a regulator of fertility. Using co-culture assays, we demonstrate that osteoblasts are able to induce testosterone production by the testes, while they fail to influence estrogen production by the ovaries. Analyses of cell-specific loss- and gain-of-function models reveal that the osteoblast-derived hormone osteocalcin performs this endocrine function. By binding to a G-protein coupled receptor expressed in the Leydig cells of the testes, osteocalcin regulates in a CREB-dependent manner the expression of enzymes required for testosterone synthesis, promoting germ cell survival. This study expands the physiological repertoire of osteocalcin, and provides the first evidence that the skeleton is an endocrine regulator of reproduction. PMID:21333348

  14. 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

  15. Non-metric variation of the infracranial skeleton.

    PubMed Central

    Finnegan, M

    1978-01-01

    196 skeletons of known age, sex and rac from the Terry Collection were studied in order to document 30 non-metric infracranial traits. Each trait had the ability to be expressed bilaterally, although significant side dimorphism was not observed. Sex differences were statistically significant for some of the traits within a racial group, but these differences were not as pronounced as the differences generated by non-metric cranial traits in the same populations, and were not effective in all racial groups. In general, these infracranial traits show some age dependency when correlation statistics are used, but this dependency is lost when the more robust chi 2 statistic is used. These data suggest that infracranial non-metric traits may be superior to cranial non-metric traits for population comparisons. Infracranial traits may be more durable than cranial traits having regard to the nature of most archaeological material. PMID:632214

  16. Principal Leadership and Organizational Commitment: The Principal Must Deliver.

    ERIC Educational Resources Information Center

    Tarter, C. John; And Others

    1989-01-01

    Theoretically, schools led by principals providing structure, resources, consideration, useful influence, and professional support in an even-handed, noncontrolling manner should be work places that elicit teacher commitment. This hypothesis was tested using a sample of 72 New Jersey secondary schools. Close control blunts teacher commitment.…

  17. Principal Concerns: Addressing Statewide Principal Pipelines with Data and Strategy

    ERIC Educational Resources Information Center

    Campbell, Christine; Gross, Bethany

    2012-01-01

    Discussions about human capital and school improvement typically center on teachers, not administrators, and that's a mistake. Principals, who are responsible for selecting and developing the teachers they know are so important, are a critical driver of school success. So it is imperative that states do everything they can to find, deploy, and…

  18. "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…

  19. Reflections on My First Year as Principal.

    ERIC Educational Resources Information Center

    Kealey, Robert J., Comp.

    This book grew out of the first principals' academy for beginning principals, hosted by the National Catholic Educational Association. Almost 60 principals, all in their first or second year as principals of Catholic elementary/middle schools, from all over the U.S. attended the program. At the conclusion of the academy, the principals wrote brief…

  20. 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

  1. 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.

  2. 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.

  3. 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)

  4. The technical aspect of the gastroepiploic artery graft skeletonization with the harmonic scalpel: the samurai technique.

    PubMed

    Kamiya, Hiroyuki; Watanabe, Go; Tomita, Shigeyuki; Takemura, Hirofumi; Nagamine, Hiroshi; Nishida, Satoru

    2005-01-01

    A novel skeletonization technique using the scissors-type harmonic scalpel (Ethicon Endo-Surgery, Cincinnati, OH, USA) is presented. This "samurai technique," which uses the harmonic scalpel by frequently turning over the scissors, facilitates the handling of the gastroepiploic artery, enlarges the caliber size, and allows easy skeletonization without any vessel injury.

  5. 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

  6. 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.

  7. Histology of “placoderm” dermal skeletons: Implications for the nature of the ancestral gnathostome

    PubMed Central

    Giles, Sam; Rücklin, Martin

    2013-01-01

    Abstract The vertebrate dermal skeleton has long been interpreted to have evolved from a primitive condition exemplified by chondrichthyans. However, chondrichthyans and osteichthyans evolved from an ancestral gnathostome stem‐lineage in which the dermal skeleton was more extensively developed. To elucidate the histology and skeletal structure of the gnathostome crown‐ancestor we conducted a histological survey of the diversity of the dermal skeleton among the placoderms, a diverse clade or grade of early jawed vertebrates. The dermal skeleton of all placoderms is composed largely of a cancellar architecture of cellular dermal bone, surmounted by dermal tubercles in the most ancestral clades, including antiarchs. Acanthothoracids retain an ancestral condition for the dermal skeleton, and we record its secondary reduction in antiarchs. We also find that mechanisms for remodeling bone and facilitating different growth rates between adjoining plates are widespread throughout the placoderms. J. Morphol., 2013. © 2013 Wiley Periodicals, Inc. PMID:23378262

  8. Ossification heterochrony in the therian postcranial skeleton and the marsupial-placental dichotomy.

    PubMed

    Weisbecker, Vera; Goswami, Anjali; Wroe, Stephen; Sánchez-Villagra, Marcelo R

    2008-08-01

    Postcranial ossification sequences in 24 therian mammals and three outgroup taxa were obtained using clear staining and computed tomography to test the hypothesis that the marsupial forelimb is developmentally accelerated, and to assess patterns of therian postcranial ossification. Sequence rank variation of individual bones, phylogenetic analysis, and algorithm-based heterochrony optimization using event pairs were employed. Phylogenetic analysis only recovers Marsupialia, Australidelphia, and Eulipotyphla. Little heterochrony is found within marsupials and placentals. However, heterochrony was observed between marsupials and placentals, relating to late ossification in hind limb long bones and early ossification of the anterior axial skeleton. Also, ossification rank position of marsupial forelimb and shoulder girdle elements is more conservative than that of placentals; in placentals the hind limb area is more conservative. The differing ossification patterns in marsupials can be explained with a combination of muscular strain and energy allocation constraints, both resulting from the requirement of active movement of the altricial marsupial neonates toward the teat. Peramelemorphs, which are comparatively passive at birth and include species with relatively derived forelimbs, differ little from other marsupials in ossification sequence. This suggests that ossification heterochrony in marsupials is not directly related to diversity constraints on the marsupial forelimb and shoulder girdle.

  9. 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…

  10. 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.…

  11. School Uniforms: Guidelines for Principals.

    ERIC Educational Resources Information Center

    Essex, Nathan L.

    2001-01-01

    Principals desiring to develop a school-uniform policy should involve parents, teachers, community leaders, and student representatives; beware restrictions on religious and political expression; provide flexibility and assistance for low-income families; implement a pilot program; align the policy with school-safety issues; and consider legal…

  12. 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…

  13. 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…

  14. Evaluating School Principals. Tips & Tools

    ERIC Educational Resources Information Center

    Brown-Sims, Melissa

    2010-01-01

    With the need to meet a set of higher accountability standards such as Interstate School Leaders Licensure Consortium (ISLLC) Standards and the AYP benchmarks of the NCLB Act, for example, school principals are faced with the knowledge that they play a vital role in school effectiveness as well as teacher retention, parent participation, and…

  15. The Principal as Instructional Leader.

    ERIC Educational Resources Information Center

    Ellis, Thomas I.

    1986-01-01

    Effective schools research has verified that schools are rarely effective unless the principal is a proficient instructional leader. This article summarizes five recent studies examining the practices and qualities comprising good instructional leadership. A Seattle study by Richard L. Andrews disclosed a statistical correlation between student…

  16. Teachers' Perspectives on Principal Mistreatment

    ERIC Educational Resources Information Center

    Blase, Joseph; Blase, Jo

    2006-01-01

    Although there is some important scholarly work on the problem of workplace mistreatment/abuse, theoretical or empirical work on abusive school principals is nonexistent. Symbolic interactionism was the theoretical structure for the present study. This perspective on social research is founded on three primary assumptions: (1) individuals act…

  17. Effective Schools Require Effective Principals

    ERIC Educational Resources Information Center

    LaPointe, Michelle; Davis, Stephen H.

    2006-01-01

    At long last, scholars and policy makers have come to realize what most school administrators have known for years--that effective schools require both outstanding teachers and strong leaders. Although there is considerable research about the characteristics of effective school leaders and the strategies principals can use to help manage…

  18. Clustering method for estimating principal diffusion directions

    PubMed Central

    Nazem-Zadeh, Mohammad-Reza; Jafari-Khouzani, Kourosh; Davoodi-Bojd, Esmaeil; Jiang, Quan; Soltanian-Zadeh, Hamid

    2012-01-01

    Diffusion tensor magnetic resonance imaging (DTMRI) is a non-invasive tool for the investigation of white matter structure within the brain. However, the traditional tensor model is unable to characterize anisotropies of orders higher than two in heterogeneous areas containing more than one fiber population. To resolve this issue, high angular resolution diffusion imaging (HARDI) with a large number of diffusion encoding gradients is used along with reconstruction methods such as Q-ball. Using HARDI data, the fiber orientation distribution function (ODF) on the unit sphere is calculated and used to extract the principal diffusion directions (PDDs). Fast and accurate estimation of PDDs is a prerequisite for tracking algorithms that deal with fiber crossings. In this paper, the PDDs are defined as the directions around which the ODF data is concentrated. Estimates of the PDDs based on this definition are less sensitive to noise in comparison with the previous approaches. A clustering approach to estimate the PDDs is proposed which is an extension of fuzzy c-means clustering developed for orientation of points on a sphere. MDL (Minimum description length) principle is proposed to estimate the number of PDDs. Using both simulated and real diffusion data, the proposed method has been evaluated and compared with some previous protocols. Experimental results show that the proposed clustering algorithm is more accurate, more resistant to noise, and faster than some of techniques currently being utilized. PMID:21642005

  19. 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...

  20. 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.

  1. 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.

  2. 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.

  3. [Anatomical names of foramina and canales in skeleton].

    PubMed

    Shikano, S; Yamashita, Y

    1998-03-01

    Latin anatomical names of Foramina and Canales in skeleton were analyzed and compared with Japanese anatomical names for better understanding of the structures of the human body and for possible revision in the future. The conclusions were as follows: 1. In general, short tunnels were called Foramina (singular: Foramen), and long tunnels Canales (singular: Canalis). 2. One end of Canalis was sometimes called Foramen. In this case, Canalis and Foramen were usually modified by the same words. 3. Each name of Foramina contained the word which means form, state, absolute size, region of existence, one of the contents or function of Foramina. 4. Each name of Canales contained the word which means region of existence, one of the contents or function of Canales. 5. Some names of Foramina and Canales that were supposed to mean the region of existence meant one of the contents of the structures. 6. As for Latin anatomical names, the relation between words were relatively clear by the proper use of noun, adjective, nominative, and genitive. 7. Since different Chinese characters were sometimes pronounced similarly in Japanese anatomical names, different structures might be confused. 8. It seemed that some Japanese anatomical names needed partial correction.

  4. The life cycle of chondrocytes in the developing skeleton.

    PubMed

    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.

  5. 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.

  6. 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.

  7. Effects of alkyl substitutions of xanthine skeleton on bronchodilation.

    PubMed

    Sakai, R; Konno, K; Yamamoto, Y; Sanae, F; Takagi, K; Hasegawa, T; Iwasaki, N; Kakiuchi, M; Kato, H; Miyamoto, K

    1992-10-30

    Structure-activity relationships in a series of 1,3,7-trialkyl-xanthine were studied with guinea pigs. Relaxant actions in the tracheal muscle were increased with alkyl chain length at the 1- and 3-positions of the xanthine skeleton, but decreased by alkylation at the 7-position. Positive chronotropic actions in the right atrium were potentiated with 3-alkyl chain length but tended to decrease with 1-alkylation and diminish by 7-substitution. Consequently, while the 1- and 3-substitutions were equally important for the tracheal smooth muscle relaxation, the substitution at the 1-position was more important than the 3-substitution for bronchoselectivity. The 7-alkylation may be significant to cancel heart stimulation. There were good correlations between the smooth muscle relaxant action and the cyclic AMP-PDE inhibitory activity in 3-substituents and the affinity for adenosine (A1) receptors in 1-, 3-, and 7-substituents. This suggests that not only the cyclic AMP-PDE inhibitory activity but also the adenosine antagonistic activity is important in the bronchodilatory effects of alkylxanthines. Among these xanthine derivatives, 1-butyl-3-propylxanthine and its 7-methylated derivative showed high bronchoselectivity in the in vitro and in vivo experiments compared to theophylline and enprofylline and may be new candidates for bronchodilator.

  8. 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

  9. Hyperostosis frontalis interna: criteria for sexing and aging a skeleton.

    PubMed

    May, Hila; Peled, Nathan; Dar, Gali; Cohen, Haim; Abbas, Janan; Medlej, Bahaa; Hershkovitz, Israel

    2011-09-01

    Estimation of sex and age in skeletons is essential in anthropological and forensic medicine investigations. The aim of the current study was to examine the potential of hyperostosis frontalis interna (HFI) as a criterion for determining sex and age in forensic cases. Macroscopic examination of the inner aspect of the frontal bone of 768 skulls (326 males and 442 females) aged 1 to 103, which had undergone a head computerized tomography scan, was carried out using the volume rendering technique. HFI was divided into two categories: minor and major. HFI is a sex- and age-dependent phenomena, with females manifesting significantly higher prevalence than males (p<0.01). In both females and males, prevalence of HFI increases as age increases (p<0.01). We present herein the probabilities of designating an unknown skull to a specific sex and age cohort according to the presence of HFI (standardized to age distribution in an Israeli population). Moreover, we present the probability of an individual belonging to a specific sex or age cohort according to age or sex (respectively) and severity of HFI. We suggest a valid, reliable, and easy method for sex and age identification of unknown skulls.

  10. Developmental mechanism of the periodic membrane skeleton in axons

    PubMed Central

    Zhong, Guisheng; He, Jiang; Zhou, Ruobo; Lorenzo, Damaris; Babcock, Hazen P; Bennett, Vann; Zhuang, Xiaowei

    2014-01-01

    Actin, spectrin, and associated molecules form a periodic sub-membrane lattice structure in axons. How this membrane skeleton is developed and why it preferentially forms in axons are unknown. Here, we studied the developmental mechanism of this lattice structure. We found that this structure emerged early during axon development and propagated from proximal regions to distal ends of axons. Components of the axon initial segment were recruited to the lattice late during development. Formation of the lattice was regulated by the local concentration of βII spectrin, which is higher in axons than in dendrites. Increasing the dendritic concentration of βII spectrin by overexpression or by knocking out ankyrin B induced the formation of the periodic structure in dendrites, demonstrating that the spectrin concentration is a key determinant in the preferential development of this structure in axons and that ankyrin B is critical for the polarized distribution of βII spectrin in neurites. DOI: http://dx.doi.org/10.7554/eLife.04581.001 PMID:25535840

  11. 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.

  12. 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.

  13. MRI of enthesitis of the appendicular skeleton in spondyloarthritis

    PubMed Central

    Eshed, Iris; Bollow, Matthias; McGonagle, Dennis G; Tan, Ai Lyn; Althoff, Christian E; Asbach, Patrick; Hermann, Kay‐Geert A

    2007-01-01

    Entheses are sites where tendons, ligaments, joint capsules or fascia attach to bone. Inflammation of the entheses (enthesitis) is a well‐known hallmark of spondyloarthritis (SpA). As entheses are associated with adjacent, functionally related structures, the concepts of an enthesis organ and functional entheses have been proposed. This is important in interpreting imaging findings in entheseal‐related diseases. Conventional radiographs and CT are able to depict the chronic changes associated with enthesitis but are of very limited use in early disease. In contrast, MRI is sensitive for detecting early signs of enthesitis and can evaluate both soft‐tissue changes and intraosseous abnormalities of active enthesitis. It is therefore useful for the early diagnosis of enthesitis‐related arthropathies and monitoring therapy. Current knowledge and typical MRI features of the most commonly involved entheses of the appendicular skeleton in patients with SpA are reviewed. The MRI appearances of inflammatory and degenerative enthesopathy are described. New options for imaging enthesitis, including whole‐body MRI and high‐resolution microscopy MRI, are briefly discussed. PMID:17526551

  14. 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.

  15. 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…

  16. How to Spot an Effective Principal.

    ERIC Educational Resources Information Center

    Finn, Chester E, Jr.

    1987-01-01

    Research shows the importance of effective principals in the development of effective schools. Discusses the importance of the principal selection process. The "Principal Selection Guide" was developed by the United States Department of Education to assist those involved in principal selection. (MD)

  17. Evaluating Principals: Recommendations at a Glance

    ERIC Educational Resources Information Center

    New Leaders for New Schools (NJ1), 2010

    2010-01-01

    Principal and teacher quality account for nearly 60% of a school's total impact on student achievement, and principals alone for a full 25% (Marzano et al., 2005). The principal's impact is so significant because of the leadership actions principals take to create the school-wide conditions that support student learning--especially those actions…

  18. Tailoring of fuzzy nanostructures on porous tungsten skeleton by helium plasma irradiation

    NASA Astrophysics Data System (ADS)

    Kajita, Shin; Tanaka, Hirohiko; Ohno, Noriyasu

    2017-03-01

    Porous tungsten skeleton, which was fabricated by sintering of tungsten powder, was exposed to helium plasmas, and the fuzzy nanostructures were tailored on the surface. The hemispherical optical reflectance of the samples was measured at the wavelength of 633 nm. It was shown that the optical reflectance of the porous tungsten skeleton was lower than that of flat tungsten samples. The minimum reflectance was ∼0.4%, suggesting that the darkest metallic material was fabricated. The advantage of the porous tungsten skeleton with nanostructures for optical application is discussed.

  19. 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.

  20. Piecewise recognition of bone skeleton profiles via an iterative Hough transform approach without re-voting

    NASA Astrophysics Data System (ADS)

    Ricca, Giorgio; Beltrametti, Mauro C.; Massone, Anna Maria

    2015-03-01

    Many bone shapes in the human skeleton are characterized by profiles that can be associated to equations of algebraic curves. Fixing the parameters in the curve equation, by means of a classical pattern recognition procedure like the Hough transform technique, it is then possible to associate an equation to a specific bone profile. However, most skeleton districts are more accurately described by piecewise defined curves. This paper utilizes an iterative approach of the Hough transform without re-voting, to provide an efficient procedure for describing the profile of a bone in the human skeleton as a collection of different but continuously attached curves.

  1. Inductive robust principal component analysis.

    PubMed

    Bao, Bing-Kun; Liu, Guangcan; Xu, Changsheng; Yan, Shuicheng

    2012-08-01

    In this paper we address the error correction problem that is to uncover the low-dimensional subspace structure from high-dimensional observations, which are possibly corrupted by errors. When the errors are of Gaussian distribution, Principal Component Analysis (PCA) can find the optimal (in terms of least-square-error) low-rank approximation to highdimensional data. However, the canonical PCA method is known to be extremely fragile to the presence of gross corruptions. Recently, Wright et al. established a so-called Robust Principal Component Analysis (RPCA) method, which can well handle grossly corrupted data [14]. However, RPCA is a transductive method and does not handle well the new samples which are not involved in the training procedure. Given a new datum, RPCA essentially needs to recalculate over all the data, resulting in high computational cost. So, RPCA is inappropriate for the applications that require fast online computation. To overcome this limitation, in this paper we propose an Inductive Robust Principal Component Analysis (IRPCA) method. Given a set of training data, unlike RPCA that targets on recovering the original data matrix, IRPCA aims at learning the underlying projection matrix, which can be used to efficiently remove the possible corruptions in any datum. The learning is done by solving a nuclear norm regularized minimization problem, which is convex and can be solved in polynomial time. Extensive experiments on a benchmark human face dataset and two video surveillance datasets show that IRPCA can not only be robust to gross corruptions, but also handle well the new data in an efficient way.

  2. 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.

  3. 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)

  4. Sexual dimorphism in the postcranial skeleton of New World primates.

    PubMed

    Leutenegger, W; Larson, S

    1985-01-01

    This study examines sexual dimorphism in 24 dimensions of the postcranial skeleton of four platyrrhine species: Callithrix jacchus, Saguinus nigricollis, Saimiri sciureus, and Cebus albifrons. The two callitrichid species show a relatively small amount of variation in the degree of sexual dimorphism among the different dimensions. Variation is considerably higher in the two cebid species as reflected by a mosaic pattern of sexual dimorphisms with males being significantly larger than females in some dimensions, and females significantly larger than males in others. In dimensions of the pectoral girdle and limb bones, males and females in each of the two cebid species are essentially scaled versions of each other, with males being peramorphic compared to females. This pattern is primarily the result of time hypermorphosis, i.e. an extension of the growth period in time in males. Rate hypermorphosis, i.e. an increase in the rate of growth in time in males, appears to play an additional role, however, in S. sciureus. By contrast, in dimensions of the true pelvis, sex differences in shape are dissociated from those in size. They are interpreted as the result of acceleration, i.e. increase in rate of shape change in females, as an adaptation to obstetrical functions. Interspecific analyses indicate positive allometry of mean degree of postcranial dimorphism with respect to body size. This coincides with previous findings by Leutenegger and Cheverud [1982, 1985] on the scaling of sexual dimorphism in body weight and canine size, and thus supports their model which posits selection on body size as the prime mover for the evolution of sexual dimorphism.

  5. 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.

  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. 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.

  8. 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.

  9. 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.

  10. 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.

  11. TRIzol and Alu qPCR-based quantification of metastatic seeding within the skeleton.

    PubMed

    Preston Campbell, J; Mulcrone, P; Masood, S K; Karolak, M; Merkel, A; Hebron, K; Zijlstra, A; Sterling, J; Elefteriou, F

    2015-08-14

    Current methods for detecting disseminated tumor cells in the skeleton are limited by expense and technical complexity. We describe a simple and inexpensive method to quantify, with single cell sensitivity, human metastatic cancer in the mouse skeleton, concurrently with host gene expression, using TRIzol-based DNA/RNA extraction and Alu sequence qPCR amplification. This approach enables precise quantification of tumor cells and corresponding host gene expression during metastatic colonization in xenograft models.

  12. 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.

  13. Using Kernel Principal Components for Color Image Segmentation

    NASA Astrophysics Data System (ADS)

    Wesolkowski, Slawo

    2002-11-01

    Distinguishing objects on the basis of color is fundamental to humans. In this paper, a clustering approach is used to segment color images. Clustering is usually done using a single point or vector as a cluster prototype. The data can be clustered in the input or feature space where the feature space is some nonlinear transformation of the input space. The idea of kernel principal component analysis (KPCA) was introduced to align data along principal components in the kernel or feature space. KPCA is a nonlinear transformation of the input data that finds the eigenvectors along which this data has maximum information content (or variation). The principal components resulting from KPCA are nonlinear in the input space and represent principal curves. This is a necessary step as colors in RGB are not linearly correlated especially considering illumination effects such as shading or highlights. The performance of the k-means (Euclidean distance-based) and Mixture of Principal Components (vector angle-based) algorithms are analyzed in the context of the input space and the feature space obtained using KPCA. Results are presented on a color image segmentation task. The results are discussed and further extensions are suggested.

  14. Principal square root of 3-subdivision-based biorthogonal wavelets.

    PubMed

    Wang, Huawei; Qin, Kaihuai; Sun, Hanqiu

    2007-01-01

    A new efficient biorthogonal wavelet analysis based on the principal square root of subdivision is proposed in the paper by using the lifting scheme. Since the principal square root of subdivision is of the slowest topological refinement among the traditional triangular subdivisions, the multiresolution analysis based on the principal square root of subdivision is more balanced than the existing wavelet analyses on triangular meshes, and accordingly offers more levels of detail for processing polygonal models. In order to optimize the multiresolution analysis process, the new wavelets, no matter whether they are interior or on boundaries, are orthogonalized with the local scaling functions based on a discrete inner product with subdivision masks. Because the wavelet analysis and synthesis algorithms are actually composed of a series of local lifting operations, they can be performed in linear time. The experiments demonstrate the efficiency and stability of the wavelet analysis for both closed and open triangular meshes with principal square root of subdivision connectivity. The principal square root of -subdivision-based biorthogonal wavelets can be used in many applications such as progressive transmission, shape approximation, multiresolution editing and rendering of 3D geometric models.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. Strategy for Sensitive and Specific Detection of Yersinia pestis in Skeletons of the Black Death Pandemic

    PubMed Central

    Seifert, Lisa; Harbeck, Michaela; Thomas, Astrid; Hoke, Nadja; Zöller, Lothar; Wiechmann, Ingrid; Grupe, Gisela; Scholz, Holger C.; Riehm, Julia M.

    2013-01-01

    Yersinia pestis has been identified as the causative agent of the Black Death pandemic in the 14th century. However, retrospective diagnostics in human skeletons after more than 600 years are critical. We describe a strategy following a modern diagnostic algorithm and working under strict ancient DNA regime for the identification of medieval human plague victims. An initial screening and DNA quantification assay detected the Y. pestis specific pla gene of the high copy number plasmid pPCP1. Results were confirmed by conventional PCR and sequence analysis targeting both Y. pestis specific virulence plasmids pPCP1 and pMT1. All assays were meticulously validated according to human clinical diagnostics requirements (ISO 15189) regarding efficiency, sensitivity, specificity, and limit of detection (LOD). Assay specificity was 100% tested on 41 clinically relevant bacteria and 29 Y. pseudotuberculosis strains as well as for DNA of 22 Y. pestis strains and 30 previously confirmed clinical human plague samples. The optimized LOD was down to 4 gene copies. 29 individuals from three different multiple inhumations were initially assessed as possible victims of the Black Death pandemic. 7 samples (24%) were positive in the pPCP1 specific screening assay. Confirmation through second target pMT1 specific PCR was successful for 4 of the positive individuals (14%). A maximum of 700 and 560 copies per µl aDNA were quantified in two of the samples. Those were positive in all assays including all repetitions, and are candidates for future continuative investigations such as whole genome sequencing. We discuss that all precautions taken here for the work with aDNA are sufficient to prevent external sample contamination and fulfill the criteria of authenticity. With regard to retrospective diagnostics of a human pathogen and the uniqueness of ancient material we strongly recommend using a careful strategy and validated assays as presented in our study. PMID:24069445

  20. 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

  1. Strategy for sensitive and specific detection of Yersinia pestis in skeletons of the black death pandemic.

    PubMed

    Seifert, Lisa; Harbeck, Michaela; Thomas, Astrid; Hoke, Nadja; Zöller, Lothar; Wiechmann, Ingrid; Grupe, Gisela; Scholz, Holger C; Riehm, Julia M

    2013-01-01

    Yersinia pestis has been identified as the causative agent of the Black Death pandemic in the 14(th) century. However, retrospective diagnostics in human skeletons after more than 600 years are critical. We describe a strategy following a modern diagnostic algorithm and working under strict ancient DNA regime for the identification of medieval human plague victims. An initial screening and DNA quantification assay detected the Y. pestis specific pla gene of the high copy number plasmid pPCP1. Results were confirmed by conventional PCR and sequence analysis targeting both Y. pestis specific virulence plasmids pPCP1 and pMT1. All assays were meticulously validated according to human clinical diagnostics requirements (ISO 15189) regarding efficiency, sensitivity, specificity, and limit of detection (LOD). Assay specificity was 100% tested on 41 clinically relevant bacteria and 29 Y. pseudotuberculosis strains as well as for DNA of 22 Y. pestis strains and 30 previously confirmed clinical human plague samples. The optimized LOD was down to 4 gene copies. 29 individuals from three different multiple inhumations were initially assessed as possible victims of the Black Death pandemic. 7 samples (24%) were positive in the pPCP1 specific screening assay. Confirmation through second target pMT1 specific PCR was successful for 4 of the positive individuals (14%). A maximum of 700 and 560 copies per µl aDNA were quantified in two of the samples. Those were positive in all assays including all repetitions, and are candidates for future continuative investigations such as whole genome sequencing. We discuss that all precautions taken here for the work with aDNA are sufficient to prevent external sample contamination and fulfill the criteria of authenticity. With regard to retrospective diagnostics of a human pathogen and the uniqueness of ancient material we strongly recommend using a careful strategy and validated assays as presented in our study.

  2. 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…

  3. 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…

  4. 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…

  5. A comparative quantitative structure-retention relationships study for lipophilicity determination of compounds with a phenanthrene skeleton on cyano-, reversed phase-, and normal phase-thin layer chromatography stationary phases.

    PubMed

    Ciura, Krzesimir; Nowakowska, Joanna; Pikul, Piotr; Struck-Lewicka, Wiktoria; Markuszewski, Michał J

    2015-01-01

    The phenanthrene skeleton is an important moiety in medical chemistry as it is present in steroidal drugs used as anti-inflammatory and anti-asthmatic agents as well as synthetic hormones or potassium sparing diuretics. Chromatographic properties of 14 derivatives containing the phenanthrene skeleton in their structure with known lipophilicity have been studied. NP, RP, and cyano-bonded silica stationary phases with three binary mobile phases (acetonitrile-water, acetone-water, and acetone-petroleum ether) were tested. Obtained chromatographic data were correlated with the lipophilicity expressed as values of log partition coefficient (P). The presented study was undertaken to find the best TLC system and chromatographic data processing method in order to predict log P values. Correlations between chromatographic data and measurements of lipophilicity of compounds were presented as results of established quantitative structure-retention relationships. Principal component analysis and cluster analysis were used to investigate the similarities among chromatographic systems.

  6. 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.

  7. 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.

  8. 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…

  9. Professional Learning Communities, Principals, and Collegial Conversations

    ERIC Educational Resources Information Center

    Spanneut, Gene

    2010-01-01

    Nearly 30 years ago, Ron Edmonds identified the instructional leadership of principals as one of the characteristics of effective schools. The connections between what principals do as instructional leaders and the successes of their schools continue to be well recognized. Principals who comprehend the significance of these linkages, however,…

  10. Analyzing the Leadership Behavior of School Principals

    ERIC Educational Resources Information Center

    Bulach, Clete; Boothe, Diane; Pickett, Winston

    2006-01-01

    The authors describe various methods of measuring a principal's leadership behavior. They have developed a new survey instrument that can be used to analyze the leadership behavior/style of a principal. The instrument consists of 49 positive and negative behaviors that measure how a principal interacts with staff in the following five leadership…

  11. 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…

  12. 37 CFR 2.46 - Principal Register.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false Principal Register. 2.46... COMMERCE RULES OF PRACTICE IN TRADEMARK CASES The Written Application § 2.46 Principal Register. All applications will be treated as seeking registration on the Principal Register unless otherwise stated in...

  13. 37 CFR 2.46 - Principal Register.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Principal Register. 2.46... COMMERCE RULES OF PRACTICE IN TRADEMARK CASES The Written Application § 2.46 Principal Register. All applications will be treated as seeking registration on the Principal Register unless otherwise stated in...

  14. 37 CFR 2.46 - Principal Register.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Principal Register. 2.46... COMMERCE RULES OF PRACTICE IN TRADEMARK CASES The Written Application § 2.46 Principal Register. All applications will be treated as seeking registration on the Principal Register unless otherwise stated in...

  15. 37 CFR 2.46 - Principal Register.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Principal Register. 2.46... COMMERCE RULES OF PRACTICE IN TRADEMARK CASES The Written Application § 2.46 Principal Register. All applications will be treated as seeking registration on the Principal Register unless otherwise stated in...

  16. 37 CFR 2.46 - Principal Register.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Principal Register. 2.46... COMMERCE RULES OF PRACTICE IN TRADEMARK CASES The Written Application § 2.46 Principal Register. All applications will be treated as seeking registration on the Principal Register unless otherwise stated in...

  17. 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…

  18. 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…

  19. 12 CFR 561.39 - Principal office.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Principal office. 561.39 Section 561.39 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY DEFINITIONS FOR REGULATIONS AFFECTING ALL SAVINGS ASSOCIATIONS § 561.39 Principal office. The term principal office means the...

  20. 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…

  1. 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…

  2. 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…

  3. 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…

  4. 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…

  5. Evaluating Principals: Balancing Accountability with Professional Growth

    ERIC Educational Resources Information Center

    New Leaders for New Schools (NJ1), 2010

    2010-01-01

    Effective principals are those who boost academic achievement for all students, increase the effectiveness of their teaching staffs, and consistently take leadership actions shown to improve outcomes for students. Therefore principal evaluation systems should place 70% of their weight on the ability of principals to increase student achievement…

  6. 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…

  7. 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…

  8. Topical vasodilator response in skeletonized internal mammary artery: Is there really a difference?

    PubMed Central

    Shah, Syed Raza; Shah, Syed Arbab; Jangda, Muhammad Ahmed; Yaqub, Mohammad Danial; Jangda, Ayesha Altaf; Khan, Maham; Khan, Muhammad Asim; Tomkins, Brian

    2017-01-01

    Aim of the Study: Coronary artery bypass graft surgery is the gold standard for the treatment of multivessel and left main coronary artery disease. However, there is considerable debate that whether left internal mammary artery (IMA) should be taken as pedicled or skeletonized. This study was conducted to assess the difference in blood flow after the application of topical vasodilator in skeletonized and pedicled IMA. Materials and Methods: In this study, each patient underwent either skeletonized (n = 25) or pedicled IMA harvesting (n = 25). The type of graft on each individual patient was decided randomly. Intraoperative variables such as conduit length and blood flow were measured by the surgeon himself. The length of the grafted IMA was carefully determined in vivo, with the proximal and distal ends attached, from the first rib to IMA divergence. The IMA flow was measured on two separate occasions, before and after application of topical vasodilator. Known cases of subclavian artery stenosis and previous sternal radiation were excluded from the study. Results: The blood flow before the application of topical vasodilator was similar in both the groups (P = 0.227). However, the flow was significantly less in pedicled than skeletonized IMA after application of vasodilator (P < 0.0001). Similarly, the length of skeletonized graft was significantly higher than the length of pedicled graft (P < 0.0001). Conclusion: Our study signifies that skeletonization of IMA results in increased graft length and blood flow after the application of topical vasodilator. However, we recommend that long-term clinical trials should be conducted to fully determine long-term patency rates of skeletonized IMA. PMID:28182034

  9. Principal Graph and Structure Learning Based on Reversed Graph Embedding.

    PubMed

    Mao, Qi; Wang, Li; Tsang, Ivor; Sun, Yijun

    2016-12-05

    Many scientific datasets are of high dimension, and the analysis usually requires retaining the most important structures of data. Principal curve is a widely used approach for this purpose. However, many existing methods work only for data with structures that are mathematically formulated by curves, which is quite restrictive for real applications. A few methods can overcome the above problem, but they either require complicated human-made rules for a specific task with lack of adaption flexibility to different tasks, or cannot obtain explicit structures of data. To address these issues, we develop a novel principal graph and structure learning framework that captures the local information of the underlying graph structure based on reversed graph embedding. As showcases, models that can learn a spanning tree or a weighted undirected `1 graph are proposed, and a new learning algorithm is developed that learns a set of principal points and a graph structure from data, simultaneously. The new algorithm is simple with guaranteed convergence. We then extend the proposed framework to deal with large-scale data. Experimental results on various synthetic and six real world datasets show that the proposed method compares favorably with baselines and can uncover the underlying structure correctly.

  10. 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.

  11. 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.

  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. 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

  15. 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.

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

    DOE PAGES

    Sottile, Matthew; Dagit, Jason; Zhang, Deli; ...

    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

  17. 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.

  18. Evaluating MJO event initiation and decay in the skeleton model using an RMM-like index

    NASA Astrophysics Data System (ADS)

    Stachnik, Justin P.; Waliser, Duane E.; Majda, Andrew J.; Stechmann, Samuel N.; Thual, Sulian

    2015-11-01

    The Madden-Julian oscillation (MJO) skeleton model is a low-order dynamic model that is capable of simulating many of the observed features of the MJO. This study develops a model-based "MJO" index that is similar to the well-known real-time multivariate MJO (RMM) index to better facilitate comparison between the skeleton model and observational data. Multivariate and univariate empirical orthogonal function (EOF) analyses were performed on the convective heating and zonal wind data taken from the skeleton model for simulations forced with an idealized warm pool and observed sea surface temperatures (SSTs). The leading EOF modes indicated a wave number 1 convectively coupled circulation anomaly with zonal asymmetries that closely resembled the observed RMM EOFs, especially when the model was forced with observed SSTs. The RMM-like index was used to compute an MJO climatology and document the occurrence of primary, continuing, and terminating MJO events in the skeleton model. The overall amount of MJO activity and event lengths compared reasonably well to observations for such a simple model. Attempts at reconciling the observed geographic distribution of individual MJO initiation and termination events were not successful for the stochastic simulations, though stochasticity is necessary in order to produce composite MJOs that initiate and decay with time scales similar to observations. Finally, analysis indicates that the existence of slow-moving, eastward traveling waves with higher wave numbers (k ≈ 12) embedded within the large-scale flow often precedes MJO termination in the skeleton model.

  19. Evaluating MJO Event Initiation and Decay in the Skeleton Model using an RMM-like Index

    NASA Astrophysics Data System (ADS)

    Stachnik, J. P.; Waliser, D. E.; Majda, A.; Stechmann, S. N.; Thual, S.

    2015-12-01

    The Madden-Julian oscillation (MJO) skeleton model is a low-order dynamic model that is capable of simulating many of the observed features of the MJO. This study develops a model- based "MJO" index that is similar to the well-known real-time multivariate MJO (RMM) index to better facilitate comparison between the skeleton model and observational data. Multivariate and univariate empirical orthogonal function (EOF) analyses were performed on the convective heating and zonal wind data taken from the skeleton model for simulations forced with an idealized warm pool and observed sea surface temperatures (SSTs). The leading EOF modes indicated a wavenumber-1 convectively-coupled circulation anomaly with zonal asymmetries that closely resembled the observed RMM EOFs, especially when the model was forced with observed SSTs. The RMM-like index was used to compute an MJO climatology and document the occurrence of primary, continuing, and terminating MJO events in the skeleton model. The overall amount of MJO activity and event lengths compared reasonably well to observations for such a simple model. Attempts at reconciling the observed geographic distribution of MJO events were not successful for the stochastic simulations, though the introduction of stochasticity to the convective parameterization was necessary in order to produce composite MJOs that initiate and decay with time scales similar to observations. Finally, analysis indicates that the existence of higher-frequency, eastward travelling waves with larger wavenumbers (k ≈ 12) embedded within the large-scale flow often precedes MJO termination in the skeleton model.

  20. 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.

  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. Nanoindentation characterization of the micro-lamellar arrangement of black coral skeleton.

    PubMed

    Juárez-de la Rosa, B A; Muñoz-Saldaña, J; Torres-Torres, D; Ardisson, P-L; Alvarado-Gil, J J

    2012-02-01

    Black corals (antipatharians) are colonial cnidarians whose branched tree-like skeleton is mostly constituted of chitin fibrils inside a lipoproteic matrix. The skeleton exhibits growth rings formed by chitin layers (micro-lamellae). In order to know the effect of the arrangement microlamellae of chitin of black corals and to improve the understanding of the role of chitin structure in the antipatharian skeleton, the mechanical properties of the skeleton of two black corals, Antipathes caribbeana and Antipathes pennacea, were examined using nanoindentation tests. Measurements of reduced elastic modulus, nanohardness and the viscoelastic behavior were measured with a spheroconical indenter. The results indicate variations in the values of the mechanical properties clearly associated with different structures present in the skeletons, the core being the one that invariably shows the maximum values. The solid multilamellar arrangement of black coral chitin, its viscoelastic behavior, and the anisotropic mechanical response, are relevant factors contributing to the successful adaptation of black coral colonies to shallow as well as to very deep waters.

  4. 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.

  5. Distributed Principal Component Analysis for Wireless Sensor Networks

    PubMed Central

    Le Borgne, Yann-Aël; Raybaud, Sylvain; Bontempi, Gianluca

    2008-01-01

    The Principal Component Analysis (PCA) is a data dimensionality reduction tech-nique well-suited for processing data from sensor networks. It can be applied to tasks like compression, event detection, and event recognition. This technique is based on a linear trans-form where the sensor measurements are projected on a set of principal components. When sensor measurements are correlated, a small set of principal components can explain most of the measurements variability. This allows to significantly decrease the amount of radio communication and of energy consumption. In this paper, we show that the power iteration method can be distributed in a sensor network in order to compute an approximation of the principal components. The proposed implementation relies on an aggregation service, which has recently been shown to provide a suitable framework for distributing the computation of a linear transform within a sensor network. We also extend this previous work by providing a detailed analysis of the computational, memory, and communication costs involved. A com-pression experiment involving real data validates the algorithm and illustrates the tradeoffs between accuracy and communication costs. PMID:27873788

  6. 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.

  7. 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.

  8. 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.

  9. Preservice Principals' Post-Internship Concerns about Becoming a Principal: America and Scotland in Review

    ERIC Educational Resources Information Center

    Hines, Mack T., III

    2008-01-01

    The purpose of this study was to compare American and Scottish preservice principals' post-internship concerns about becoming a principal. The survey findings for this study showed that overall American preservice principals were more concerned about becoming principals than their Scottish preservice counterparts. Based on the groups' discussion…

  10. Conditioning of sewage sludge by Fenton's reagent combined with skeleton builders.

    PubMed

    Liu, Huan; Yang, Jiakuan; Shi, Yafei; Li, Ye; He, Shu; Yang, Changzhu; Yao, Hong

    2012-06-01

    Physical conditioners, often known as skeleton builders, are commonly used to improve the dewaterability of sewage sludge. This study evaluated a novel joint usage of Fenton's reagent and skeleton builders, referred to as the F-S inorganic composite conditioner, focusing on their efficacies and the optimization of the major operational parameters. The results demonstrate that the F-S composite conditioner for conditioning sewage sludge is a viable alternative to conventional organic polymers, especially when ordinary Portland cement (OPC) and lime are used as the skeleton builders. Experimental investigations confirmed that Fenton reaction required sufficient time (80 min in this study) to degrade organics in the sludge. The optimal condition of this process was at pH=5, Fe(2+)=40 mg g(-1) (dry solids), H(2)O(2)=32 mg g(-1), OPC=300 mg g(-1) and lime=400 mg g(-1), in which the specific resistance to filtration reduction efficiency of 95% was achieved.

  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. The new hominid skeleton from Sterkfontein, South Africa: age and preliminary assessment

    NASA Astrophysics Data System (ADS)

    Partridge, Timothy C.; Shaw, John; Heslop, David; Clarke, Ronald J.

    1999-07-01

    A new hominid skeleton from Sterkfontein Member 2 attaches to foot bones recovered from loose blocks during the 1980s and first described in 1995. Several flowstone horizons are present above and below the skeleton and have given clear palaeomagnetic signatures. Five changes in magnetic polarity have been identified; when constrained by the available biostratigraphy, this sequence can be placed confidently between 3.22 and 3.58 Ma. Interpolation of sedimentation rates over the small intervals between reversals allows this range to be reduced to 3.30-3.33 Ma. The skeleton is thus the oldest yet discovered and is considered to belong to a species of Australopithecus other than africanus.

  14. 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.

  15. 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).

  16. 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.

  17. 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.

  18. Numerical investigation of oscillatory multiphase flow in porous medium with chemically active skeleton

    NASA Astrophysics Data System (ADS)

    Konyukhov, A. V.; Zavialov, I. N.

    2016-11-01

    Self-oscillating mode of reaction front propagation in multiphase flow in the porous medium with chemically active skeleton is investigated numerically. The considered flow represents an immiscible displacement process, such that the displacing fluid and the skeleton of the porous medium have chemically active components which react with production of gaseous phase. The calculations have demonstrated strong influence of the reaction kinetics on stability of the reactive flow. The presence of a time delay between the change of concentration of the reactants and the change of the reaction rate is shown to stimulate transition of the reaction front propagation to the oscillatory mode.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. Non-Conventional Carbon Nanotube Skeleton Reinforced Composites for Space Applications

    NASA Astrophysics Data System (ADS)

    Hepp, Felicitas; Pfeiffer, E. K.; Pereira, C.; Martins, M.; Liedtke, V.; Macho, C.; Aschenbrenner, O.; Forero, S.; Linke, S.; Masouras, A.; Vavouliotis, A.; Kostopoulos, V.; Wulz, H.-G.; Pambaguian, L.

    2014-06-01

    Carbon Nanotubes (CNT) embedded in composite materials like CFRP, polymers or ceramics, can improve specific performance characteristics such as e.g. electrical conductivity, mechanical fatigue and crack propagation, mechanical properties, alpha/epsilon values, PIM-reduction, EMC shielding, etc.CNT skeletons, also called Bucky papers and Bucky discs, are macroscopic aggregates of Carbon Nanotubes. These skeletons are used in composites with different matrices, namely metal, ceramic or polymer or directly used in CFRP composites.The aim is to increase the performance of composite space structures by increasing the material characteristics or provide composites with additional sensing abilities like structural health monitoring.

  4. 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.

  5. 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.

  6. 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.

  7. Matrix and mineral in the sea urchin larval skeleton.

    PubMed

    Wilt, F H

    1999-06-30

    The endoskeletal spicules of sea urchin larvae are composed of calcite, a surrounding extracellular matrix, and small amounts of occluded matrix proteins. The spicules are formed by primary mesenchyme cells (PMCs) in the blastocoel of the embryo, where they adopt stereotypical locations, thereby specifying where spicules will form. PMCs also fuse to form cytoplasmic cords connecting the cell bodies, and it is within the cords that spicules arise. The mineral phase contains 5% Mg as well as Ca, and about 0.1% of the mass is protein. The matrix and mineral form concentric plies, and the composite has different physical properties than those of pure calcite. The calcite diffracts as a single crystal and is composed of well-ordered, but not perfectly ordered, microdomains. There is evidence for adsorption of matrix proteins to specific crystal faces at domain boundaries, which may help regulate crystal growth and texture. Immature spicules contain considerable precipitated amorphous CaCO3, and PMCs also have vesicles that contain amorphous CaCO3. This suggests the hypothesis that the cellular precursor to the spicules is actually amorphous CaCO3 stabilized in the cell by protein. The spicule s enveloped by the PMC cord, but is topologically exterior to the cell. The PMC plasmalemma is tightly applied to the developing spicules, except perhaps at the elongating tip. The characteristics, localization, and possible function of the four identified matrix proteins are discussed. SM50, SM37, and PM27 all primarily enclose the mineral, though small amounts are occluded. SM30 is found in cellular vesicles and is probably the principal occluded protein of the spicule.

  8. A comparative study of staff removal algorithms.

    PubMed

    Dalitz, Christoph; Droettboom, Michael; Pranzas, Bastian; Fujinaga, Ichiro

    2008-05-01

    This paper presents a quantitative comparison of different algorithms for the removal of stafflines from music images. It contains a survey of previously proposed algorithms and suggests a new skeletonization based approach. We define three different error metrics, compare the algorithms with respect to these metrics and measure their robustness with respect to certain image defects. Our test images are computer-generated scores on which we apply various image deformations typically found in real-world data. In addition to modern western music notation our test set also includes historic music notation such as mensural notation and lute tablature. Our general approach and evaluation methodology is not specific to staff removal, but applicable to other segmentation problems as well.

  9. Quantum Algorithms

    NASA Technical Reports Server (NTRS)

    Abrams, D.; Williams, C.

    1999-01-01

    This thesis describes several new quantum algorithms. These include a polynomial time algorithm that uses a quantum fast Fourier transform to find eigenvalues and eigenvectors of a Hamiltonian operator, and that can be applied in cases for which all know classical algorithms require exponential time.

  10. Evaluation Priorities of Students, Teachers, and Principals.

    ERIC Educational Resources Information Center

    Nevo, David; Stufflebeam, Daniel L.

    The main purposes of this study were to identify the evaluation needs of students, teachers, and principals, and to develop recommendations for an evaluation system within the school building. Students, teachers, and principals were surveyed to depict the availability and importance of eight different categories of evaluative information derived…

  11. Special Topic/The Principal's Priority 1

    ERIC Educational Resources Information Center

    Johnson, Jean

    2008-01-01

    Five Public Agenda surveys--A Mission of the Heart (2008); Lessons Learned (2008); Reality Check 2006; Rolling Up Their Sleeves (2003); and Stand by Me (2003)--provide snapshots of how instructional leadership is working in schools. Most principals see instructional leadership as a key mission. "Transformer" principals are able to focus squarely…

  12. Essential Knowledges and Skills for Beginning Principals.

    ERIC Educational Resources Information Center

    Kelly, Noeline

    The purpose of this literature review is to produce a list of essential knowledge and skills for beginning principals. Research on the principalship falls into two distinct categories: prescriptive and descriptive. Prescriptive research emphasizes the perceived or idealized role of the principal as "bold innovator" or "creative…

  13. Do Principals Fire the Worst Teachers?

    ERIC Educational Resources Information Center

    Jacob, Brian A.

    2011-01-01

    This article takes advantage of a unique policy change to examine how principals make decisions regarding teacher dismissal. In 2004, the Chicago Public Schools (CPS) and Chicago Teachers Union signed a new collective bargaining agreement that gave principals the flexibility to dismiss probationary teachers for any reason and without the…

  14. Democratic Principals in Action: Eight Pioneers.

    ERIC Educational Resources Information Center

    Blase, Joseph; And Others

    This book was written for teachers and principals committed to instituting shared governance and more democratic forms of leadership and to help understand today's principalship and what it means to administer a shared-governance school. The data were derived from a study of successful principals in schools affiliated with the League of…

  15. 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…

  16. THE PRINCIPAL'S ROLE IN COLLECTIVE NEGOTIATIONS.

    ERIC Educational Resources Information Center

    LONG, RICHARD P.; RHODES, ERIC F.

    PROBLEMS OF THE SCHOOL PRINCIPAL'S ROLE AS THE MIDDLEMAN IN COLLECTIVE NEGOTIATIONS BETWEEN SCHOOL BOARDS AND TEACHER ORGANIZATIONS ARE IDENTIFIED WITHIN THE NEW RELATIONSHIP OF TEACHERS AND ADMINISTRATORS IN PUBLIC SCHOOL SYSTEMS. THE PRINCIPAL IS VIEWED AS THE ADMINISTRATIVE AUTHORITY AND RESPONSIBLE DECISIONMAKER ON QUESTIONS OF ADMINISTRATION…

  17. 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…

  18. 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…

  19. 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.…

  20. 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,…

  1. 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…

  2. Investigating Roles of Online School Principals

    ERIC Educational Resources Information Center

    Quilici, Sarah B.; Joki, Russell

    2012-01-01

    This study explores the instructional leadership skills required from online principals, as defined by one state's (Idaho) adaptation of the Interstate School Leaders Licensure Consortium (ISLLC) standards (1996) as a requirement for professional certification. Specifically, this qualitative study examined six sets of paired online principals and…

  3. Urban Principals' Second Order Change Leadership

    ERIC Educational Resources Information Center

    Taylor, Rosemarye T.; La Cava, Gonzalo S.

    2011-01-01

    Urban school leaders have challenges in continually improving student achievement and making change as quickly as needed. To address this problem 37 non-Title I principals completed an on-line survey, Principal's Actions Survey (PAS), based on the seven responsibilities for second order change identified by Marzano, Waters, and McNulty (2005).…

  4. Relationship Building: The First "R" for Principals

    ERIC Educational Resources Information Center

    Rieg, Sue A.; Marcoline, Joseph F.

    2008-01-01

    School leadership today demands skills, knowledge, and attitudes much different than those required a short time ago. With the increased accountability for principals to achieve and maintain adequate yearly progress, test scores are often seen by teachers and parents as principals' top priority. Relationships are seen as secondary and they should…

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. The Principal, School Discipline, and the Law.

    ERIC Educational Resources Information Center

    Hurwitz, Howard L.

    In this booklet, the Council of Supervisors and Administrators of the City of New York seeks to offer hope that teachers' and principals' capacity for the reasonable exercise of authority has not been exhausted. There is a body of legal opinion that supports the authority of the principal in disciplinary matters. It is a misconception that a…

  11. Perceived Educational Values of Omani School Principals

    ERIC Educational Resources Information Center

    Al-Ani, Wajeha Thabit; Al-Harthi, Aisha Salim

    2017-01-01

    This qualitative study investigated the perceived educational values of Omani school principals. Data were collected using a semi-structured interview form which focused on the core values of school administration as perceived by a sample of 44 school principals; a focus group interview was also held. Data were analysed using Nvivo software. The…

  12. Principals Judge Teachers by Their Teaching

    ERIC Educational Resources Information Center

    Nixon, Andy; Packard, Abbot; Dam, Margaret

    2013-01-01

    This quantitative study investigated the relationship between teacher dispositions, subject content knowledge, pedagogical content knowledge, and reasons that school principals recommend non-renewal of probationary teachers' contracts. Principals in the Southeastern Unites States completed an e-mailed survey. Two nonparametric tests,…

  13. 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…

  14. How Not to Prepare School Principals

    ERIC Educational Resources Information Center

    Davis, Stephen H.; Leon, Ronald J.

    2011-01-01

    Instead of focusing on how principals should be trained, an contrarian view is offered, grounded upon theoretical perspectives of experiential learning, and in particular, upon the theory of andragogy. A brief parable of the DoNoHarm School of Medicine is used as a descriptive analog for many principal preparation programs in America. The…

  15. 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 formation…

  16. Management Philosophies of Primary School Principals

    ERIC Educational Resources Information Center

    Tas, Said

    2011-01-01

    The study aimed to determine the management philosophies of primary school principals. Stratification method of sampling was used in the study. The study sample consisted of 33 school principals and 132 teachers serving at primary education schools in Isparta in the academic year 2008-2009. The "Manager Philosophy Scale" developed by Tanriogen and…

  17. Principal Selection Panels: Strategies, Preferences and Perceptions

    ERIC Educational Resources Information Center

    Walker, Allan; Kwan, Paula

    2012-01-01

    Purpose: The purpose of this article is to report a study of the strategies members of principal selection panels use to select the best candidate for a principal position. Design/methodology/approach: The study draws on both qualitative and quantitative data. The quantitative analysis drawn on data collected from school supervisors and school…

  18. 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…

  19. Untapped Resources: Assistant Principals as Instructional Leaders

    ERIC Educational Resources Information Center

    Bartholomew, Selma K.; Melendez-Delaney, Genis; Orta, Awilda; White, Sharon

    2005-01-01

    Assistant principals are often overlooked as a resource for creating, advancing, and sustaining a compelling vision for mathematics. The Math Collaborative Project developed in New York City examined the process of developing and implementing programs designed to help assistant principals network and strengthen their instructional leadership…

  20. 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…

  1. Primary School Principals' Self-Monitoring Skills

    ERIC Educational Resources Information Center

    Konan, Necdet

    2015-01-01

    The aim of the present study is to identify primary school principals' self-monitoring skills. The study adopted the general survey model and its population comprised primary school principals serving in the city of Diyarbakir, Turkey, while 292 of these constituted the sample. Self-Monitoring Scale was used as the data collection instrument. In…

  2. 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…

  3. 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…

  4. 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…

  5. Women Principals Leading Learning at "Poverty's Edge"

    ERIC Educational Resources Information Center

    Lyman, Linda L.

    2008-01-01

    The author profiles two women principals of color who have successfully enhanced student learning in high-poverty schools. In their leadership narratives, the principals address how the complexity of poverty affects their work, how they affirm the worth and dignity of all, how they influence beliefs and attitudes of staff, why they think their…

  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. 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…

  8. 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.

  9. 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…

  10. 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…

  11. 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…

  12. Strategic Plans and Principals' Need for Control.

    ERIC Educational Resources Information Center

    Nir, Adam E.

    2000-01-01

    Investigates the extent that principals' managerial behavior is related to their beliefs about control. Argues for a negative relation between extreme locus of control and perspectives used by individuals for strategic and long-term plans. "Extreme control" principals produce strategic plans with shorter perspectives. (Contains 56…

  13. The Principal as Change Facilitator. Bulletin 1753.

    ERIC Educational Resources Information Center

    Louisiana State Dept. of Education, Baton Rouge. Louisiana Dissemination Network.

    This monograph surveys the literature relating to the role of the principal as change agent and the process of educational change, and reviews those characteristics that research has found to make principals more effective and efficient change agents. The introduction identifies four relevant perspectives in the research on instructional…

  14. 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…

  15. 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…

  16. New Principals' Perspectives of Their Multifaceted Roles

    ERIC Educational Resources Information Center

    Gentilucci, James L.; Denti, Lou; Guaglianone, Curtis L.

    2013-01-01

    This study utilizes Symbolic Interactionism to explore perspectives of neophyte principals. Findings explain how these perspectives are modified through complex interactions throughout the school year, and they also suggest preparation programs can help new principals most effectively by teaching "soft" skills such as active listening…

  17. 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.

  18. 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…

  19. 32 CFR 716.1 - Principal rule.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 5 2014-07-01 2014-07-01 false Principal rule. 716.1 Section 716.1 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL DEATH GRATUITY Provisions Applicable to the Navy and the Marine Corps § 716.1 Principal rule. Under title 10 U.S.C., section 1475,...

  20. Principal Leadership: Factors Sustaining Successful School Innovation

    ERIC Educational Resources Information Center

    Alvarez, Cristina Candelaria

    2010-01-01

    The study examines how urban school principals lead schools that make a difference for children in challenging settings. This research delves deeply into the experiences of three urban public school principals in the School District of Philadelphia in Pennsylvania, who used technology as an avenue to improve educational options for their students.…

  1. Implementing IDEA: A Guide for Principals.

    ERIC Educational Resources Information Center

    Council for Exceptional Children, Arlington, VA.

    This guide is designed to provide information on ensuring quality special education services and early intervention to building principals in elementary and middle schools. It sets forth standards of excellence that directly relate to implementing the Individuals with Disabilities Education Act (IDEA) and presents guidelines for principals to use…

  2. 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.…

  3. 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.

  4. 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.

  5. Structure of salvioccidentalin, a diterpenoid with a rearranged neo-clerodane skeleton from Salvia occidentalis.

    PubMed

    Jaime-Vasconcelos, Miguel Ángel; Frontana-Uribe, Bernardo Antonio; Morales-Serna, José Antonio; Salmón, Manuel; Cárdenas, Jorge

    2011-10-31

    From the aerial parts of Salvia occidentalis (Labiatae) a new diterpenoid with a rearranged neo-clerodane skeleton was isolated. This new compound was named salvioccidentalin and its structure was established by spectroscopic means. A probable biogenetic relationship with salvigenolide from S. fulgens and salvileucalin A and spiroleucantholide from Salvia leucantha is proposed.

  6. 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.

  7. 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.

  8. Determination of the Halogenated Skeleton Constituents of the Marine Demosponge Ianthella basta.

    PubMed

    Ueberlein, Susanne; Machill, Susanne; Schupp, Peter J; Brunner, Eike

    2017-02-10

    Demosponges of the order Verongida such as Ianthella basta exhibit skeletons containing spongin, a collagenous protein, and chitin. Moreover, Verongida sponges are well known to produce bioactive brominated tyrosine derivatives. We recently demonstrated that brominated compounds do not only occur in the cellular matrix but also in the skeletons of the marine sponges Aplysina cavernicola and I. basta. Further investigations revealed the amino acid composition of the skeletons of A. cavernicola including the presence of several halogenated amino acids. In the present work, we investigated the skeletal amino acid composition of the demosponge I. basta, which belongs to the Ianthellidae family, and compared it with that of A. cavernicola from the Aplysinidae family. Seventeen proteinogenic and five non-proteinogenic amino acids were detected in I. basta. Abundantly occurring amino acids like glycine and hydroxyproline show the similarity of I. basta and A. cavernicola and confirm the collagenous nature of their sponging fibers. We also detected nine halogenated tyrosines as an integral part of I. basta skeletons. Since both sponges contain a broad variety of halogenated amino acids, this seems to be characteristic for Verongida sponges. The observed differences of the amino acid composition confirm that spongin exhibits a certain degree of variability even among the members of the order Verongida.

  9. 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…

  10. 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

  11. Determination of the Halogenated Skeleton Constituents of the Marine Demosponge Ianthella basta

    PubMed Central

    Ueberlein, Susanne; Machill, Susanne; Schupp, Peter J.; Brunner, Eike

    2017-01-01

    Demosponges of the order Verongida such as Ianthella basta exhibit skeletons containing spongin, a collagenous protein, and chitin. Moreover, Verongida sponges are well known to produce bioactive brominated tyrosine derivatives. We recently demonstrated that brominated compounds do not only occur in the cellular matrix but also in the skeletons of the marine sponges Aplysina cavernicola and I. basta. Further investigations revealed the amino acid composition of the skeletons of A. cavernicola including the presence of several halogenated amino acids. In the present work, we investigated the skeletal amino acid composition of the demosponge I. basta, which belongs to the Ianthellidae family, and compared it with that of A. cavernicola from the Aplysinidae family. Seventeen proteinogenic and five non-proteinogenic amino acids were detected in I. basta. Abundantly occurring amino acids like glycine and hydroxyproline show the similarity of I. basta and A. cavernicola and confirm the collagenous nature of their sponging fibers. We also detected nine halogenated tyrosines as an integral part of I. basta skeletons. Since both sponges contain a broad variety of halogenated amino acids, this seems to be characteristic for Verongida sponges. The observed differences of the amino acid composition confirm that spongin exhibits a certain degree of variability even among the members of the order Verongida. PMID:28208597

  12. Transgenic overexpression of bone morphogenetic protein 11 propeptide in skeleton enhances bone formation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bone morphogenetic protein 11 (BMP11) is a key regulatory protein in skeletal development. BMP11 propeptide has been shown to antagonize GDF11 activity in vitro. To explore the role of BMP11 propeptide in skeletal formation in vivo, we generated transgenic mice with skeleton-specific overexpression...

  13. 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.

  14. 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…

  15. 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.

  16. 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…

  17. Representation Learning of Temporal Dynamics for Skeleton-Based Action Recognition.

    PubMed

    Du, Yong; Fu, Yun; Wang, Liang

    2016-07-01

    Motion characteristics of human actions can be represented by the position variation of skeleton joints. Traditional approaches generally extract the spatial-temporal representation of the skeleton sequences with well-designed hand-crafted features. In this paper, in order to recognize actions according to the relative motion between the limbs and the trunk, we propose an end-to-end hierarchical RNN for skeleton-based action recognition. We divide human skeleton into five main parts in terms of the human physical structure, and then feed them to five independent subnets for local feature extraction. After the following hierarchical feature fusion and extraction from local to global, dimensions of the final temporal dynamics representations are reduced to the same number of action categories in the corresponding data set through a single-layer perceptron. In addition, the output of the perceptron is temporally accumulated as the input of a softmax layer for classification. Random scale and rotation transformations are employed to improve the robustness during training. We compare with five other deep RNN variants derived from our model in order to verify the effectiveness of the proposed network. In addition, we compare with several other methods on motion capture and Kinect data sets. Furthermore, we evaluate the robustness of our model trained with random scale and rotation transformations for a multiview problem. Experimental results demonstrate that our model achieves the state-of-the-art performance with high computational efficiency.

  18. Natural collagenic skeleton of marine sponges in pharmaceutics: Innovative biomaterial for topical drug delivery.

    PubMed

    Langasco, Rita; Cadeddu, Barbara; Formato, Marilena; Lepedda, Antonio Junior; Cossu, Massimo; Giunchedi, Paolo; Pronzato, Roberto; Rassu, Giovanna; Manconi, Renata; Gavini, Elisabetta

    2017-01-01

    The growing interest in the use of recyclable and biodegradable natural materials has become a relevant topic in pharmaceutics. In this work, we suggest the use and valorization of natural horny skeleton of marine sponges (Porifera, Dictyoceratida) as bio-based dressing for topical drug delivery. Biomaterial characterization focusing on morpho-functional traits, swelling behavior, fluid uptake performances, glycosaminoglycans content and composition and microbiological quality assessment was carried out to investigate the collagenic skeleton properties. After grinding and sieving processes, l-cysteine hydrochloride-loaded formulations were designed in form of powder or polymeric film by testing various drug concentrations and different drying parameters. Drug content, SEM analyses and in vitro permeation studies were performed to test the suitability of skeleton-based formulations. To this respect, drying time and temperature are key parameters for skeleton-mediated drug crystallization. Consequently, this behavior seems to influence drug loading and permeation profiles of formulations. The high percentages of drug are found after absorption into sponge powder and in vitro permeation studies demonstrate that cysteine is released more slowly than the pure drug within 1h. Such a system is attractive because it combines the known healing properties of cysteine with the advantageous potentials of the collagen/proteoglycan network, which can act as biocompatible carrier able to absorb the excess of the wound exudate while releasing the drug. Furthermore, due to its glycosaminoglycans content, natural sponge skeletal scaffold might act as bioactive-biomimetic carrier regulating the wound healing processes.

  19. 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…

  20. 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…

  1. 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

  2. Talent identification and deliberate programming in skeleton: ice novice to Winter Olympian in 14 months.

    PubMed

    Bullock, Nicola; Gulbin, Jason P; Martin, David T; Ross, Angus; Holland, Terry; Marino, Frank

    2009-02-15

    The aims of this study were to talent transfer, rapidly develop, and qualify an Australian female athlete in the skeleton event at the 2006 Torino Winter Olympic Games and quantify the volume of skeleton-specific training and competition that would enable this to be achieved. Initially, 26 athletes were recruited through a talent identification programme based on their 30-m sprint time. After attending a selection camp, 10 athletes were invited to undertake an intensified skeleton training programme. Four of these athletes were then selected to compete for Australia on the World Cup circuit. All completed runs and simulated push starts were documented over a 14-month period. The athlete who eventually represented Australia at the Torino Winter Olympic Games did so following approximately 300 start simulations and about 220 training/competition runs over a period of 14 months. Using a deliberate programming model, these findings provide a guide to the minimum exposure required for a novice skeleton athlete to reach Olympic representative standard following intensified sport-specific training. The findings of this study are discussed in the context of the deliberate practice theory and offer the term "deliberate programming" as an alternative way of incorporating all aspects of expert development.

  3. Deformable modeling using a 3D boundary representation with quadratic constraints on the branching structure of the Blum skeleton.

    PubMed

    Yushkevich, Paul A; Zhang, Hui Gary

    2013-01-01

    We propose a new approach for statistical shape analysis of 3D anatomical objects based on features extracted from skeletons. Like prior work on medial representations, the approach involves deforming a template to target shapes in a way that preserves the branching structure of the skeleton and provides intersubject correspondence. However, unlike medial representations, which parameterize the skeleton surfaces explicitly, our representation is boundary-centric, and the skeleton is implicit. Similar to prior constrained modeling methods developed 2D objects or tube-like 3D objects, we impose symmetry constraints on tuples of boundary points in a way that guarantees the preservation of the skeleton's topology under deformation. Once discretized, the problem of deforming a template to a target shape is formulated as a quadratically constrained quadratic programming problem. The new technique is evaluated in terms of its ability to capture the shape of the corpus callosum tract extracted from diffusion-weighted MRI.

  4. Non-rigid registration of small animal skeletons from micro-CT using 3D shape context

    NASA Astrophysics Data System (ADS)

    Xiao, Di; Bourgeat, Pierrick; Fripp, Jurgen; Acosta Tamayo, Oscar; Gregoire, Marie Claude; Salvado, Olivier

    2009-02-01

    Small animal registration is an important step for molecular image analysis. Skeleton registration from whole-body or only partial micro Computerized Tomography (CT) image is often performed to match individual rats to atlases and templates, for example to identify organs in positron emission tomography (PET). In this paper, we extend the shape context matching technique for 3D surface registration and apply it for rat hind limb skeleton registration from CT images. Using the proposed method, after standard affine iterative closest point (ICP) registration, correspondences between the 3D points from sour and target objects were robustly found and used to deform the limb skeleton surface with thin-plate-spline (TPS). Experiments are described using phantoms and actual rat hind limb skeletons. On animals, mean square errors were decreased by the proposed registration compared to that of its initial alignment. Visually, skeletons were successfully registered even in cases of very different animal poses.

  5. 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.

  6. Scalable Robust Principal Component Analysis using Grassmann Averages.

    PubMed

    Hauberg, Soren; Feragen, Aasa; Enficiaud, Raffi; Black, Michael

    2015-12-23

    In large datasets, manual data verification is impossible, and we must expect the number of outliers to increase with data size. While principal component analysis (PCA) can reduce data size, and scalable solutions exist, it is well-known that outliers can arbitrarily corrupt the results. Unfortunately, state-of-the-art approaches for robust PCA are not scalable. We note that in a zero-mean dataset, each observation spans a one-dimensional subspace, giving a point on the Grassmann manifold. We show that the average subspace corresponds to the leading principal component for Gaussian data. We provide a simple algorithm for computing this Grassmann Average (GA), and show that the subspace estimate is less sensitive to outliers than PCA for general distributions. Because averages can be efficiently computed, we immediately gain scalability. We exploit robust averaging to formulate the Robust Grassmann Average (RGA) as a form of robust PCA. The resulting Trimmed Grassmann Average (TGA) is appropriate for computer vision because it is robust to pixel outliers. The algorithm has linear computational complexity and minimal memory requirements. We demonstrate TGA for background modeling, video restoration, and shadow removal. We show scalability by performing robust PCA on the entire Star Wars IV movie; a task beyond any current method. Source code is available online.

  7. Scalable Robust Principal Component Analysis Using Grassmann Averages.

    PubMed

    Hauberg, Sren; Feragen, Aasa; Enficiaud, Raffi; Black, Michael J

    2016-11-01

    In large datasets, manual data verification is impossible, and we must expect the number of outliers to increase with data size. While principal component analysis (PCA) can reduce data size, and scalable solutions exist, it is well-known that outliers can arbitrarily corrupt the results. Unfortunately, state-of-the-art approaches for robust PCA are not scalable. We note that in a zero-mean dataset, each observation spans a one-dimensional subspace, giving a point on the Grassmann manifold. We show that the average subspace corresponds to the leading principal component for Gaussian data. We provide a simple algorithm for computing this Grassmann Average ( GA), and show that the subspace estimate is less sensitive to outliers than PCA for general distributions. Because averages can be efficiently computed, we immediately gain scalability. We exploit robust averaging to formulate the Robust Grassmann Average (RGA) as a form of robust PCA. The resulting Trimmed Grassmann Average ( TGA) is appropriate for computer vision because it is robust to pixel outliers. The algorithm has linear computational complexity and minimal memory requirements. We demonstrate TGA for background modeling, video restoration, and shadow removal. We show scalability by performing robust PCA on the entire Star Wars IV movie; a task beyond any current method. Source code is available online.

  8. 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.

  9. 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.

  10. Selecting the Number of Principal Components in Functional Data

    PubMed Central

    Li, Yehua; Wang, Naisyin; Carroll, Raymond J.

    2013-01-01

    Functional principal component analysis (FPCA) has become the most widely used dimension reduction tool for functional data analysis. We consider functional data measured at random, subject-specific time points, contaminated with measurement error, allowing for both sparse and dense functional data, and propose novel information criteria to select the number of principal component in such data. We propose a Bayesian information criterion based on marginal modeling that can consistently select the number of principal components for both sparse and dense functional data. For dense functional data, we also developed an Akaike information criterion (AIC) based on the expected Kullback-Leibler information under a Gaussian assumption. In connecting with factor analysis in multivariate time series data, we also consider the information criteria by Bai & Ng (2002) and show that they are still consistent for dense functional data, if a prescribed undersmoothing scheme is undertaken in the FPCA algorithm. We perform intensive simulation studies and show that the proposed information criteria vastly outperform existing methods for this type of data. Surprisingly, our empirical evidence shows that our information criteria proposed for dense functional data also perform well for sparse functional data. An empirical example using colon carcinogenesis data is also provided to illustrate the results. PMID:24376287

  11. Selecting the Number of Principal Components in Functional Data.

    PubMed

    Li, Yehua; Wang, Naisyin; Carroll, Raymond J

    2013-12-19

    Functional principal component analysis (FPCA) has become the most widely used dimension reduction tool for functional data analysis. We consider functional data measured at random, subject-specific time points, contaminated with measurement error, allowing for both sparse and dense functional data, and propose novel information criteria to select the number of principal component in such data. We propose a Bayesian information criterion based on marginal modeling that can consistently select the number of principal components for both sparse and dense functional data. For dense functional data, we also developed an Akaike information criterion (AIC) based on the expected Kullback-Leibler information under a Gaussian assumption. In connecting with factor analysis in multivariate time series data, we also consider the information criteria by Bai & Ng (2002) and show that they are still consistent for dense functional data, if a prescribed undersmoothing scheme is undertaken in the FPCA algorithm. We perform intensive simulation studies and show that the proposed information criteria vastly outperform existing methods for this type of data. Surprisingly, our empirical evidence shows that our information criteria proposed for dense functional data also perform well for sparse functional data. An empirical example using colon carcinogenesis data is also provided to illustrate the results.

  12. Geochemical study of coral skeletons from the Puerto Morelos Reef, southeastern Mexico

    NASA Astrophysics Data System (ADS)

    Kasper-Zubillaga, Juan J.; Armstrong-Altrin, John S.; Rosales-Hoz, Leticia

    2014-12-01

    Geochemical analyses in coral skeletons have been used as a proxy of marine environmental conditions and to understand the mechanisms of adsorption of chemical elements into the coral skeletons and growth forms. However, little attention has been given to show the possible differences in the growth rates of corals based upon major, trace, rare earth element and microprobe analyses to examine the physical-chemical conditions influencing those differences. Our goal is to show how branch and fan corals incorporate elements into their skeletons comparing them with their coral growth rates. We determine the development of the skeletons of two branching (Acropora palmata, Acropora cervicornis) and one fan shaped (Gorgonia ventalina) colonies in the Puerto Morelos Reef, southeastern Mexico based upon geochemical data and the influence of terrigenous input into the species. Mg and Sr concentrations were the most statistically significant elements among the species studied suggesting that Mg concentration in Gorgonia ventalina is probably not linked to its growth rate. Mn content in the sea water is adsorbed by the three corals during past growth rates during high rainfall events. Sr concentration may be associated with the growth rate of Acropora palmata. Little differences in the growth rate in Acropora palmata may be associated with low rates of calcitization, negligible changes in the Sr concentration and little influence of temperature and water depth in its growth. Trace elements like Cr, Co, Ni and V adsorbed by the corals are influenced by natural concentration of these elements in the sea-water. Rare earth elements in the corals studied suggests abundant inorganic ions CO32- with variable pH in modern shallow well-oxygenated sea water. Lack of terrigenous input seawards is supported by geochemical, geomorphological and biological evidences. This study is an example of how geochemical data are useful to observe the differences in environmental conditions related to

  13. 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.

  14. 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:…

  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. Measuring Principals' Effectiveness: Results from New Jersey's Principal Evaluation Pilot. REL 2015-089

    ERIC Educational Resources Information Center

    Ross, Christine; Herrmann, Mariesa; Angus, Megan Hague

    2015-01-01

    The purpose of this study was to describe the measures used to evaluate principals in New Jersey in the first (pilot) year of the new principal evaluation system and examine three of the statistical properties of the measures: their variation among principals, their year-to-year stability, and the associations between these measures and the…

  17. 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…

  18. Understanding the Principal's Contribution to Instruction: Seven Principals, Seven Stories. Methodology.

    ERIC Educational Resources Information Center

    Dwyer, David C.; And Others

    Existing qualitative studies of school principals suffer from procedural or conceptual shortcomings that result in failure to clarify the principal's instructional role. This paper describes the methodology and procedures of a year-long, multimethod, multilevel field study of 12 school principals. First, the background for the study (the…

  19. Relationship between Principals' Sense of Achievement and Teachers' Perceptions of Their Principals' Leadership Behaviors

    ERIC Educational Resources Information Center

    Siddiqi, Javaid Edward

    2012-01-01

    The purpose of the study was to examine the relationship between principals' sense of achievement and teachers' perceptions of their principals' leadership behaviors. This was determined by examining job satisfaction of principals and leadership style using the Minnesota Satisfaction Questionnaire (MSQ) and the School District's Climate Survey.…

  20. The Impact of Principal Movement and School Achievement on Principal Salaries

    ERIC Educational Resources Information Center

    Tran, Henry; Buckman, David G.

    2017-01-01

    This study examines whether principals' movements and school achievement are associated with their salaries. Predictors of principal salaries were examined using three years of panel data. Results from a fixed-effects regression analysis suggest that principals who moved to school leadership positions in other districts leveraged higher salaries…

  1. What Makes a Successful Principal? Incorporating School Principal Background in State and District Policy

    ERIC Educational Resources Information Center

    Pierson, Ashley

    2014-01-01

    School principals' education and professional experience shape their approach to school leadership and how successful their students will be. However, it is not clear from existing research which aspects of principal education and professional experience are related to student outcomes and principal retention. This dissertation explores aspects of…

  2. 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,…

  3. Synthesis of novel triplet drugs with 1,3,5-trioxazatriquinane skeletons and their pharmacologies. 1: Synthesis of triplet drugs with morphinan skeletons.

    PubMed

    Nagase, Hiroshi; Watanabe, Akio; Nemoto, Toru; Nakajima, Mayumi; Hasebe, Ko; Mochizuki, Hidenori; Fujii, Hideaki

    2011-07-01

    We synthesized symmetrical and nonsymmetrical triplet drugs with 1,3,5-trioxazatriquinane skeletons. The isolation of key intermediates, oxazoline dimers, made it possible to effectively produce nonsymmetrical triplets. Among the synthesized triplets, KNT-93, composed of three identical opioid μ receptor agonists, showed dose-dependent antinociception via the μ receptor. The effect was 56-fold more potent than that of morphine, a representative μ agonist. The profound analgesic effect induced by KNT-93 might result from simultaneous occupation of three μ opioid receptors.

  4. Optimized principal component analysis on coronagraphic images of the fomalhaut system

    SciTech Connect

    Meshkat, Tiffany; Kenworthy, Matthew A.; Quanz, Sascha P.; Amara, Adam

    2014-01-01

    We present the results of a study to optimize the principal component analysis (PCA) algorithm for planet detection, a new algorithm complementing angular differential imaging and locally optimized combination of images (LOCI) for increasing the contrast achievable next to a bright star. The stellar point spread function (PSF) is constructed by removing linear combinations of principal components, allowing the flux from an extrasolar planet to shine through. The number of principal components used determines how well the stellar PSF is globally modeled. Using more principal components may decrease the number of speckles in the final image, but also increases the background noise. We apply PCA to Fomalhaut Very Large Telescope NaCo images acquired at 4.05 μm with an apodized phase plate. We do not detect any companions, with a model dependent upper mass limit of 13-18 M {sub Jup} from 4-10 AU. PCA achieves greater sensitivity than the LOCI algorithm for the Fomalhaut coronagraphic data by up to 1 mag. We make several adaptations to the PCA code and determine which of these prove the most effective at maximizing the signal-to-noise from a planet very close to its parent star. We demonstrate that optimizing the number of principal components used in PCA proves most effective for pulling out a planet signal.

  5. Deriving Paleotemperatures From Coral Skeleton Using a Rayleigh Fractionation Model for Coral Biomineralization

    NASA Astrophysics Data System (ADS)

    Gaetani, G. A.; Cohen, A. L.; Wang, Z.

    2007-12-01

    Paleotemperature proxy records are typically derived from coral skeleton using empirical relationships between elemental ratios and water temperature calibrated using the skeletons of living organisms grown under known conditions. While this approach has produced significant advances in our understanding of Earth's climate system, its accuracy is limited by the influence of physiological processes ("vital effects") on compositional variability within the skeleton. "Vital effects" are evident as differences in the composition of carbonates precipitated experimentally and accreted by organisms at the same conditions, as well as differences in composition amongst skeletons of the same group of organisms, or even the same species, accreted under identical environmental conditions. Several recent studies have identified the importance of Rayleigh fractionation in producing "vital effects" in coral skeleton [1-3]. On the basis of this advance in our understanding of coral biomineralization, we have developed a new approach to deriving paleotemperature estimates from coral skeletons through knowledge of their combined Mg/Ca, Sr/Ca and Ba/Ca ratios. Using experimentally determined partition coefficients for Mg, Ca, Sr, and Ba between abiogenic aragonite and seawater [1] combined with a Rayleigh fractionation model for the precipitation of aragonite from a calcifying fluid, the temperature at which the aragonite was precipitated can be accurately determined. To test the accuracy and precision of this approach, which relies only on experimentally determined partition coefficients for abiogenic aragonite and the Rayleigh equation (i.e. contrary to conventional paleothermometer calibrations, no prior knowledge of water temperature is required), aragonite skeletons from 2 different coral species were analyzed for Mg/Ca, Sr/Ca and Ba/Ca ratios using the Cameca 3f ion microprobe at WHOI: (1) tropical coral Diploria labyrinthiformis collected from Bermuda and (2) deep water coral

  6. How a Lighthouse Principal Revitalized His School.

    ERIC Educational Resources Information Center

    Reavis, Charles A.

    1986-01-01

    Outlines the steps a "lighthouse" principal took in turning an ineffective school characterized by low morale, poor achievement, and high absentee rates into an effective school with high morale and improved student achievement during a six-month period. (MD)

  7. Attitudes of Principals Toward Participatory Managerial Practices

    ERIC Educational Resources Information Center

    Wendel, Frederick C.

    1977-01-01

    In order to identify more precisely the extent to which building principals adhere to participatory managerial practices, a study was conducted to assess their attitudes toward selected policies of participatory managerial practices. (Author)

  8. Principal's Roles and Teacher Conflict: A Recapitulation.

    ERIC Educational Resources Information Center

    Cheek, Earl H., Jr.; Lindsey, Jimmy D.

    1986-01-01

    Principals should perform functions in three major areas: (1) interpersonal relationships (leader, figurehead, liaison); (2) information processing (disseminator, spokesperson); and (3) decision making (change agent, disturbance handler, resource allocator, negotiator, and evaluator). (CL)

  9. Check List: Are You a Gifted Principal?

    ERIC Educational Resources Information Center

    Taylor, Vicki L.

    1984-01-01

    An 18-item check list is provided for principals to evaluate themselves relative to encouraging gifts and talents of their most able students. Suggestions are given in the areas of educational needs, specialized materials, and counseling. (MC)

  10. Paranoia: Perceptions of Public School Principals.

    ERIC Educational Resources Information Center

    Salmon, Daniel A.

    1980-01-01

    Examines forces which are undermining the principal's leadership role and ability to effectively administer the school: teachers and unions; the competency movement; political and community interest groups; and media pundits. (SJL)

  11. Dynamic competitive probabilistic principal components analysis.

    PubMed

    López-Rubio, Ezequiel; Ortiz-DE-Lazcano-Lobato, Juan Miguel

    2009-04-01

    We present a new neural model which extends the classical competitive learning (CL) by performing a Probabilistic Principal Components Analysis (PPCA) at each neuron. The model also has the ability to learn the number of basis vectors required to represent the principal directions of each cluster, so it overcomes a drawback of most local PCA models, where the dimensionality of a cluster must be fixed a priori. Experimental results are presented to show the performance of the network with multispectral image data.

  12. Hollow silica-copper-carbon anodes using copper metal-organic frameworks as skeletons

    NASA Astrophysics Data System (ADS)

    Sun, Zixu; Xin, Fengxia; Cao, Can; Zhao, Chongchong; Shen, Cai; Han, Wei-Qiang

    2015-12-01

    Hollow silica-copper-carbon (H-SCC) nanocomposites are first synthesized using copper metal-organic frameworks as skeletons to form Cu-MOF@SiO2 and then subjected to heat treatment. In the composites, the hollow structure and the void space from the collapse of the MOF skeleton can accommodate the huge volume change, buffer the mechanical stress caused by lithium ion insertion/extraction and maintain the structural integrity of the electrode and a long cycling stability. The ultrafine copper with a uniform size of around 5 nm and carbon with homogeneous distribution from the decomposition of the MOF skeleton can not only enhance the electrical conductivity of the composite and preserve the structural and interfacial stabilization, but also suppress the aggregation of silica nanoparticles and cushion the volume change. In consequence, the resulting material as an anode for lithium-ion batteries (LIBs) delivers a reversible capacity of 495 mA h g-1 after 400 cycles at a current density of 500 mA g-1. The synthetic method presented in this paper provides a facile and low-cost strategy for the large-scale production of hollow silica/copper/carbon nanocomposites as an anode in LIBs.Hollow silica-copper-carbon (H-SCC) nanocomposites are first synthesized using copper metal-organic frameworks as skeletons to form Cu-MOF@SiO2 and then subjected to heat treatment. In the composites, the hollow structure and the void space from the collapse of the MOF skeleton can accommodate the huge volume change, buffer the mechanical stress caused by lithium ion insertion/extraction and maintain the structural integrity of the electrode and a long cycling stability. The ultrafine copper with a uniform size of around 5 nm and carbon with homogeneous distribution from the decomposition of the MOF skeleton can not only enhance the electrical conductivity of the composite and preserve the structural and interfacial stabilization, but also suppress the aggregation of silica nanoparticles and

  13. Morphological interaction between the nasal septum and nasofacial skeleton during human ontogeny.

    PubMed

    Goergen, Matthew J; Holton, Nathan E; Grünheid, Thorsten

    2017-05-01

    The nasal septal cartilage is thought to be a key growth center that contributes to nasofacial skeletal development. Despite the developmental influence of the nasal septum however, humans often exhibit a high frequency of septal deviation suggesting discordance in the growth between the septum and surrounding nasofacial skeleton. While there are numerous etiological factors that contribute to septal deviation, the surrounding nasofacial skeleton may also act to constrain the septum, resulting in altered patterns of growth. That is, while the nasal septum has a direct morphogenetic influence on aspects of the nasofacial skeleton, other nasofacial skeletal components may restrict septal growth resulting in deviation. Detailing the developmental relationship between these structures is important not only for understanding the causal determinants of nasal septal deviation, but also for developing a broader understanding of the complex interaction between the facial skeleton and chondrocranium. We selected 66 non-syndromic subjects from the University of Minnesota Orthodontic Clinic who ranged from 7 to 18 years in age and had an existing pretreatment cone-beam computed tomography (CBCT) scan. Using CBCT data, we examined the developmental relationship between nasal septal deviation and the surrounding nasofacial skeleton. We measured septal deviation as a percentage of septal volume relative to a modeled non-deviated septum. We then collected a series of coordinate landmark data in the region immediately surrounding the nasal septum in the midsagittal plane representing the nasofacial skeleton. First, we examined ontogenetic changes in the magnitude of nasal septal deviation relative to chronological age and nasofacial size. Next, using Procrustes-based geometric morphometric techniques, we assessed the morphological relationship between nasal septal deviation and nasofacial skeletal shape. Our results indicate that variation in the magnitude of nasal septal

  14. Immorally obtained principal increases investors’ risk preference

    PubMed Central

    Chen, Jiaxin; He, Guibing

    2017-01-01

    Capital derived from immoral sources is increasingly circulated in today’s financial markets. The moral associations of capital are important, although their impact on investment remains unknown. This research aims to explore the influence of principal source morality on investors’ risk preferences. Three studies were conducted in this regard. Study 1 finds that investors are more risk-seeking when their principal is earned immorally (through lying), whereas their risk preferences do not change when they invest money earned from neutral sources after engaging in immoral behavior. Study 2 reveals that guilt fully mediates the relationship between principal source morality and investors’ risk preferences. Studies 3a and 3b introduce a new immoral principal source and a new manipulation method to improve external validity. Guilt is shown to the decrease the subjective value of morally flawed principal, leading to higher risk preference. The findings show the influence of morality-related features of principal on people’s investment behavior and further support mental account theory. The results also predict the potential threats of “grey principal” to market stability. PMID:28369117

  15. Computing Steerable Principal Components of a Large Set of Images and Their Rotations

    PubMed Central

    Ponce, Colin; Singer, Amit

    2013-01-01

    We present here an efficient algorithm to compute the Principal Component Analysis (PCA) of a large image set consisting of images and, for each image, the set of its uniform rotations in the plane. We do this by pointing out the block circulant structure of the covariance matrix and utilizing that structure to compute its eigenvectors. We also demonstrate the advantages of this algorithm over similar ones with numerical experiments. Although it is useful in many settings, we illustrate the specific application of the algorithm to the problem of cryo-electron microscopy. PMID:21536533

  16. Computing steerable principal components of a large set of images and their rotations.

    PubMed

    Ponce, Colin; Singer, Amit

    2011-11-01

    We present here an efficient algorithm to compute the Principal Component Analysis (PCA) of a large image set consisting of images and, for each image, the set of its uniform rotations in the plane. We do this by pointing out the block circulant structure of the covariance matrix and utilizing that structure to compute its eigenvectors. We also demonstrate the advantages of this algorithm over similar ones with numerical experiments. Although it is useful in many settings, we illustrate the specific application of the algorithm to the problem of cryo-electron microscopy.

  17. Comparison of observed skeleton retention of strontium in average indian adult with the value predicted by the ICRP biokinetic model.

    PubMed

    Nair, Suma; Pradhan, A S; Jaiswal, D D; Singh, I S; Garg, S P

    2006-01-01

    The daily dietary intake of strontium and its content in skeleton, for an Indian adult population group were estimated by experimentally measuring its concentration in total cooked diet and autopsy skeleton samples using radiochemical neutron activation analysis. The data on daily dietary intake of strontium were used to compute its contents in skeleton using ICRP Publication 67 biokinetic model for strontium. The theoretically computed value of strontium (213.8 mg) compared favourably with the measured values (GM 181.2 mg) in an urban population group living in Mumbai representing an average Indian adult (Reference Indian Man).

  18. (+)-Rimocidin Synthetic Studies: Construction of the C(1-27) Aglycone Skeleton

    PubMed Central

    Smith, Amos B.; Foley, Megan A.; Dong, Shuzhi; Orbin, Alia

    2010-01-01

    Assembly of the C(1-27) macrocyclic skeleton of rimocidinolide, the aglycone of (+)-rimocidin (1), has been achieved in convergent fashion. Key features of the synthetic strategy entail application of multicomponent Type 1 Anion Relay Chemistry (ARC), in conjunction with the SN2/SN2' reaction manifolds of vinyl epoxides, both employing 2-susbtituted-1,3-dithianes to construct the C(1-19) carbon backbone. Yamaguchi union of a C(20-27) vinyl borate ester, possessing the all trans triene, with an advanced C(1-19) vinyl iodide followed by macrocyclization via Suzuki-Miyaura cross-coupling completed construction of the C(1-27) rimocidinolide skeleton. PMID:19621880

  19. Synthesis of a Novel Quinoline Skeleton Introduced Cationic Polyfluorene Derivative for Multimodal Antimicrobial Application.

    PubMed

    Sun, Han; Yin, Bohan; Ma, Hongli; Yuan, Huanxiang; Fu, Bin; Liu, Libing

    2015-11-18

    A new functional polyfluorene derivative containing quinoline skeleton and quarternary ammonium group (QAG) modified side chains (PFPQ) was synthesized and characterized. The multimodal antimicrobial effect toward Gram-negative E. coli was achieved by the dark toxicity resulting from the quinoline skeleton, QAG, and light toxicity resulting from reactive oxygen species (ROS) produced by the main backbone of PFPQ under white light. The mechanism of interaction between PFPQ and bacteria was also demonstrated. PFPQ bound to E. coli mainly through electrostatic interactions causing nearly 50% bacterial death in the absence of light irradiation, and the huge capability of PFPQ to generate ROS under white light opened another bactericidal mode. The killing efficiency was more than 99% upon relatively mild irradiation under white light (400-800 nm) with a light dose of 18 J·cm(-2). PFPQ with the incorporation of quinoline into the backbones will provide a new versatile strategy to achieve the multimodal antimicrobial effect to fight against resistant bacteria.

  20. Antitumor activity and structure-activity relationship of diterpenoids with a dehydroabietyl skeleton.

    PubMed

    Rao, Xiaoping; Huang, Xiuzhi; He, Ling; Song, Jie; Song, Zhanqian; Shang, Shibin

    2012-12-01

    A series of novel diterpenoids including imines, amides and ureas with a dehydroabietyl skeleton were screened to hepatocellular carcinoma (SMMC-7721), lung cancer (A-549), glioma (C-6) and breast carcinoma (MCF-7) tumor cells by MTT method. Their antitumor activity and structure activity relationship were analyzed. Several of the title compounds such as I-2, I-10, I-6 and I-5, possess noticeable antitumor activity against SMMC-7721, A-549, C-6 and MCF-7 tumor cells, with lowest IC(50) values of 6.65, 0.75, 0.81 and 10.65μM, respectively. Based on the structure-activity relationship investigation, the three kinds of diterpenoids with a dehydroabietyl skeleton show high activity to SMMC-7721 cells. Imines derivatives exhibit broad spectrum and highly efficient activities to the selected four kinds of tumor cells.

  1. Insights into the Skeletonization, Lifestyle, and Affinity of the Unusual Ediacaran Fossil Corumbella

    PubMed Central

    Pacheco, Mírian L. A. Forancelli; Galante, Douglas; Rodrigues, Fabio; de M. Leme, Juliana; Bidola, Pidassa; Hagadorn, Whitey; Stockmar, Marco; Herzen, Julia; Rudnitzki, Isaac D.; Pfeiffer, Franz; Marques, Antonio C.

    2015-01-01

    The Ediacaran fossil Corumbella is important because it is hypothesized to be a scyphozoan cnidarian, and thus might be one of the rare examples of bona fide Neoproterozoic animals. Unfortunately, its mode of life, style of skeletonization, and taxonomic affinity have been very controversial. Here, we use X-ray micro-CT, SEM, and taphonomic analysis to compare preservational modes of Corumbella, in order to better understand the symmetry, mode of construction, preservational style, and taxonomy of this group. Results suggest that articulated and disarticulated specimens of Corumbella from the Ediacaran of Brazil, Paraguay, and the United States, although sometimes preserved very differently, represent the same taxon—Corumbella werneri. Corumbellids had a thick but flexible theca and probably lived with their basalmost part anchored in the sediment, much like Conotubus. When considered together, these results suggest that Corumbella was one of the first animals to build a skeleton, employing a lamellar microfabric similar to conulariids. PMID:25822998

  2. Comparison of Contact Stress Distribution for Foam Seat and Seat of Auxetic Spring Skeleton

    NASA Astrophysics Data System (ADS)

    Janus-Michalska, M.; Jasińska, D.; Smardzewski, J.

    2013-03-01

    The objective of this paper is to present and compare the results of numerical solutions of contact problem for two types of seats subjected to typical sitting loadings. The first seat is made of a typical hyperelastic foam, the other is designed with an auxetic polyamid spring skeleton. Computer simulations of the seat structure under a typical static loading exerted by a human body are performed by means of ABAQUS FEA. The model provides an insight into deformation modes and stress field in relation to geometric and material parameters of the seat structure.The other type of seat, due to the fact of global auxecity and progressive springs characteristics reduces contact stress concentrations, giving an advantegous distribution of pressure and provides the sensation of physical comfort. The proper seat skeleton shape leads to an improvement of ergonomic quality.

  3. Fast Na/+/-ion transport in skeleton structures. [solid electrolyte applications

    NASA Technical Reports Server (NTRS)

    Goodenough, J. B.; Hong, H. Y.-P.; Kafalas, J. A.

    1976-01-01

    The skeleton structures considered in the investigations consist of a rigid subarray with an interconnected interstitial space in which ions move in three dimensions. The classes of skeleton structures investigated include the Im3 phase of high-pressure KSbO3, the defect-pyrochlore structure illustrated by RbMgAlF6, and the carnegieite structure of high-temperature NaAlSiO4. A description is given of the results obtained in transport measurements involving dense polycrystalline ceramic disks. Results obtained in the case of the Na(+)-ion transport in Na3Zr2PSi2O12 appear particularly promising concerning the possible use of such substances in solid-electrolyte applications.

  4. Aspects of the dosimetry of radionuclides within the skeleton with particular emphasis on the active marrow

    SciTech Connect

    Eckerman, K.F.

    1985-01-01

    Epidemiological surveys on man and results from animal experiments have shown that two tissues associated with the skeleton are of primary concern with respect to cancer induction by ionizing radiation. These are the cells on or near endosteal surfaces of bone, from which osteosarcomas are thought to arise, and hematopoietic bone marrow, which is associated with leukemia. The complex geometry of the soft tissue-bone intermixture makes calculations of absorbed dose to these target regions a difficult problem. In the case of photon or neutron radiations, charged particle equilibrium may not exist in the vicinity of soft tissue-bone mineral interface. In this paper a general study of the dosimetry of radionuclides within the skeleton is presented. Dosimetric data consistent with the MIRD schema and reflecting the physical and anatomical parameters defining the energy deposition are tabulated for the relevant target regions. 27 refs., 5 figs., 5 tabs.

  5. In vivo imaging of coral tissue and skeleton with optical coherence tomography.

    PubMed

    Wangpraseurt, Daniel; Wentzel, Camilla; Jacques, Steven L; Wagner, Michael; Kühl, Michael

    2017-03-01

    Application of optical coherence tomography (OCT) for in vivo imaging of tissue and skeleton structure of intact living corals enabled the non-invasive visualization of coral tissue layers (endoderm versus ectoderm), skeletal cavities and special structures such as mesenterial filaments and mucus release from intact living corals. Coral host chromatophores containing green fluorescent protein-like pigment granules appeared hyper-reflective to near-infrared radiation allowing for excellent optical contrast in OCT and a rapid characterization of chromatophore size, distribution and abundance. In vivo tissue plasticity could be quantified by the linear contraction velocity of coral tissues upon illumination resulting in dynamic changes in the live coral tissue surface area, which varied by a factor of 2 between the contracted and expanded state of a coral. Our study provides a novel view on the in vivo organization of coral tissue and skeleton and highlights the importance of microstructural dynamics for coral ecophysiology.

  6. Autonomic management of multiple non-functional concerns in behavioural skeletons

    NASA Astrophysics Data System (ADS)

    Aldinucci, Marco; Danelutto, Marco; Kilpatrick, Peter

    We introduce and address the problem of concurrent autonomic management of different non-functional concerns in parallel applications build as a hierarchical composition of behavioural skeletons. We first define the problems arising when multiple concerns are dealt with by independent managers, then we propose a methodology supporting coordinated management, and finally we discuss how autonomic management of multiple concerns may be implemented in a typical use case. Being based on the behavioural skeleton concept proposed in the CoreGRID GCM, it is anticipated that the methodology will be readily integrated into the current reference implementation of GCM based on Java ProActive and running on top of major grid middleware systems.

  7. Sinoscrewtine, an alkaloid with novel skeleton from the roots of Sinomenium acutum.

    PubMed

    Wang, Xiao-Ling; Liu, Bing-Rui; Chen, Chien-Kuang; Qin, Guo-Wei; Lee, Shoei-Sheng

    2013-01-01

    An alkaloid with novel skeleton, sinoscrewtine (1), has been isolated from the roots of Sinomenium acutum. Its structure was established by spectral analysis and X-ray crystallographic study, and its possible biosynthetic pathway was delivered. In vitro experiments, 1 showed weak injurious effects against H(2)O(2)/Aβ(25-35) induced oxidative injury in PC-12 cells and DPPH radical scavenging activity with IC(50) of 32.6μM.

  8. Evaluating MJO Event Initiation and Decay in the Skeleton Model using an RMM-like Index

    DTIC Science & Technology

    2015-11-25

    convective 30 heating and zonal wind data taken from the skeleton model for simulations forced with an 31 idealized warm pool and observed sea...surface temperatures (SSTs). The leading EOF modes 32 indicated a wavenumber-1 convectively -coupled circulation anomaly with zonal asymmetries 33 that...The MJO represents a 47 convectively -coupled mode of cloud and circulation anomalies on the planetary scale (i.e., 48 wavenumbers 1-3) with an

  9. Cloning Nacre's 3D Interlocking Skeleton in Engineering Composites to Achieve Exceptional Mechanical Properties.

    PubMed

    Zhao, Hewei; Yue, Yonghai; Guo, Lin; Wu, Juntao; Zhang, Youwei; Li, Xiaodong; Mao, Shengcheng; Han, Xiaodong

    2016-07-01

    Ceramic/polymer composite equipped with 3D interlocking skeleton (3D IL) is developed through a simple freeze-casting method, exhibiting exceptionally light weight, high strength, toughness, and shock resistance. Long-range crack energy dissipation enabled by 3D interlocking structure is considered as the primary reinforcing mechanism for such superior properties. The smart composite design strategy should hold a place in developing future structural engineering materials.

  10. Strategies for construction of the all-carbon macrocyclic skeleton of the ansamycin antibiotic-kendomycin.

    PubMed

    Xu, Shu; Arimoto, Hirokazu

    2016-04-01

    Kendomycin, an ansamycin-type natural product first reported in 1996, possesses a series of attractive bioactivities and a unique all-carbon macrocyclic skeleton. To the date, seven total syntheses, two formal total syntheses and a number of synthetic studies on this hot molecule have been reported. In this short review article, we mainly survey and comment on these efforts regarding the difficult macrocyclization strategies.

  11. Antimalarial diterpenoid dimers of a new carbon skeleton from Aphanamixis grandifolia.

    PubMed

    Zhang, Hua; Liu, Jia; Gan, Li-She; Dalal, Seema; Cassera, Maria B; Yue, Jian-Min

    2016-01-21

    Chemical investigation into the minor constituents of Aphanamixis grandifolia yielded three new diterpenoid dimers, aphadilactones E-G (1-3) featuring a new carbon skeleton. Their structures and absolute configurations were fully established by comprehensive spectroscopic data analysis and ECD calculation. Discovery of another two new dimers (4 and 5) suggested the structure of recently reported aphanamene A to be re-investigated. Compounds 1-5 showed moderate antimalarial activities with low micromolar IC50 values.

  12. The Diaza[5.5.6.6]fenestrane Skeleton-Synthesis of Leuconoxine Alkaloids.

    PubMed

    Pfaffenbach, Magnus; Gaich, Tanja

    2016-03-07

    Among the Aspidosperma-derived monoterpene indole alkaloids, the leuconoxine subgroup has drawn significant attention from the synthetic community during the past few years. This Minireview summarizes the hitherto six completed total syntheses of leuconoxines emphasizing the different strategies for assembling the key structural motif, an unprecedented diaza[5.5.6.6]fenestrane skeleton. In addition, the proposed biogenetic relationships within the group of these alkaloids are described.

  13. Contribution of myocardium hydraulic skeleton to left ventricular wall interaction and synergy in dogs.

    PubMed

    Barra, Juan Gabriel; Crottogini, Alberto José; Willshaw, Peter; Lascano, Elena Catalina; Pichel, Ricardo Horacio

    2004-08-01

    The most premature motion change after coronary occlusion is early diastolic thinning of the ischemic left ventricular (LV) wall, with concomitant thickening of the normoperfused wall. We aimed 1). to demonstrate that these early changes are the result of the absence of fluid within the ischemic myocardium (hydraulic skeleton) rather than to cell anoxia and 2). to quantitate the contribution of the lack of hydraulic skeleton to left ventricular asynergy of contraction in seven anesthetized dogs submitted to acute, short-lasting circumflex artery (Cx) occlusion (ischemia) and to perfusion of the Cx with an oxygen-free solution (anoxia). We analyzed the time course of regional work index (WI, area of the LV pressure-wall thickness loop) and regional efficiency (defined as the ratio of WI to the maximum possible work). Interwall asynergy was defined as the difference between the regional efficiency of the anterior and posterior walls. After 9-10 s, posterior wall efficiency decreased 37 +/- 6% with anoxia and 72 +/- 3% with ischemia (P < 0.025), and interwall asynergy was 0 +/- 6% with anoxia and 32 +/- 5% with ischemia (P < 0.05). The contribution of absent hydraulic skeleton to interwall asynergy (calculated as the difference between %asynergy in anoxia and %asynergy in ischemia) was 30 +/- 8% (P < 0.05). In conclusion, the earliest wall motion change observed after acute coronary occlusion, namely ischemic wall thinning concomitant with normoperfused wall thickening during isovolumic relaxation, is the result of the absence of intracoronary fluid. The lack of hydraulic skeleton within the myocardium contributes approximately 30% to interwall asynergy.

  14. Design and Enantioselective Construction of Axially Chiral Naphthyl-Indole Skeletons.

    PubMed

    Zhang, Hong-Hao; Wang, Cong-Shuai; Li, Can; Mei, Guang-Jian; Li, Yuxue; Shi, Feng

    2017-01-02

    The first enantioselective construction of a new class of axially chiral naphthyl-indole skeletons has been established by organocatalytic asymmetric coupling reactions of 2-naphthols with 2-indolylmethanols (up to 99 % yield, 97:3 e.r.). This approach not only affords a new type of axially chiral heterobiaryl backbone, but also provides a new catalytic enantioselective strategy for constructing axially chiral biaryl scaffolds by making use of the C3-electrophilicity of 2-indolylmethanols.

  15. Ready Access to the Echinopines Skeleton via Gold(I)-Catalyzed Alkoxycyclizations of Enynes.

    PubMed

    Dorel, Ruth; Echavarren, Antonio M

    2016-09-16

    The [3,5,5,7] tetracyclic skeleton of echinopines has been stereoselectively accessed through a gold(I)-catalyzed alkoxycyclization of cyclopropyl-tethered 1,6-enynes. The key bicyclo[4.2.1]nonane core of the enyne precursors was readily assembled by means of a Co-catalyzed [6 + 2] cycloaddition. Furthermore, the attempted alkoxycyclization of 1,5-enyne substrates revealed an uncovered cyclopropyl rearrangement that gives rise to [3,6,5,7] tetracyclic structures.

  16. Ready Access to the Echinopines Skeleton via Gold(I)-Catalyzed Alkoxycyclizations of Enynes

    PubMed Central

    2016-01-01

    The [3,5,5,7] tetracyclic skeleton of echinopines has been stereoselectively accessed through a gold(I)-catalyzed alkoxycyclization of cyclopropyl-tethered 1,6-enynes. The key bicyclo[4.2.1]nonane core of the enyne precursors was readily assembled by means of a Co-catalyzed [6 + 2] cycloaddition. Furthermore, the attempted alkoxycyclization of 1,5-enyne substrates revealed an uncovered cyclopropyl rearrangement that gives rise to [3,6,5,7] tetracyclic structures. PMID:27529429

  17. The origin and diversification of the developmental mechanisms that pattern the vertebrate head skeleton.

    PubMed

    Square, Tyler; Jandzik, David; Romášek, Marek; Cerny, Robert; Medeiros, Daniel Meulemans

    2016-11-21

    The apparent evolvability of the vertebrate head skeleton has allowed a diverse array of shapes, sizes, and compositions of the head in order to better adapt species to their environments. This encompasses feeding, breathing, sensing, and communicating: the head skeleton somehow participated in the evolution of all these critical processes for the last 500 million years. Through evolution, present head diversity was made possible via developmental modifications to the first head skeletal genetic program. Understanding the development of the vertebrate common ancestor's head skeleton is thus an important step in identifying how different lineages have respectively achieved their many innovations in the head. To this end, cyclostomes (jawless vertebrates) are extremely useful, having diverged from jawed vertebrates approximately 400 million years ago, at the deepest node within living vertebrates. From this ancestral vantage point (that is, the node connecting cyclostomes and gnathostomes) we can best identify the earliest major differences in development between vertebrate classes, and start to address how these might translate onto morphology. In this review we survey what is currently known about the cell biology and gene expression during head development in modern vertebrates, allowing us to better characterize the developmental genetics driving head skeleton formation in the most recent common ancestor of all living vertebrates. By pairing this vertebrate composite with information from fossil chordates, we can also deduce how gene regulatory modules might have been arranged in the ancestral vertebrate head. Together, we can immediately begin to understand which aspects of head skeletal development are the most conserved, and which are divergent, informing us as to when the first differences appear during development, and thus which pathways or cell types might be involved in generating lineage specific shape and structure.

  18. Automatic and hierarchical segmentation of the human skeleton in CT images.

    PubMed

    Fu, Yabo; Liu, Shi; Li, Harold; Yang, Deshan

    2017-04-07

    Accurate segmentation of each bone of the human skeleton is useful in many medical disciplines. The results of bone segmentation could facilitate bone disease diagnosis and post-treatment assessment, and support planning and image guidance for many treatment modalities including surgery and radiation therapy. As a medium level medical image processing task, accurate bone segmentation can facilitate automatic internal organ segmentation by providing stable structural reference for inter- or intra-patient registration and internal organ localization. Even though bones in CT images can be visually observed with minimal difficulty due to the high image contrast between the bony structures and surrounding soft tissues, automatic and precise segmentation of individual bones is still challenging due to the many limitations of the CT images. The common limitations include low signal-to-noise ratio, insufficient spatial resolution, and indistinguishable image intensity between spongy bones and soft tissues. In this study, a novel and automatic method is proposed to segment all the major individual bones of the human skeleton above the upper legs in CT images based on an articulated skeleton atlas. The reported method is capable of automatically segmenting 62 major bones, including 24 vertebrae and 24 ribs, by traversing a hierarchical anatomical tree and by using both rigid and deformable image registration. The degrees of freedom of femora and humeri are modeled to support patients in different body and limb postures. The segmentation results are evaluated using the Dice coefficient and point-to-surface error (PSE) against manual segmentation results as the ground-truth. The results suggest that the reported method can automatically segment and label the human skeleton into detailed individual bones with high accuracy. The overall average Dice coefficient is 0.90. The average PSEs are 0.41 mm for the mandible, 0.62 mm for cervical vertebrae, 0.92 mm for thoracic

  19. Elliptical erythrocyte membrane skeletons and heat-sensitive spectrin in hereditary elliptocytosis.

    PubMed

    Tomaselli, M B; John, K M; Lux, S E

    1981-03-01

    Erythrocyte membranes (ghosts) and membrane skeletons (submembranous reticula of spectrin, actin, and protein 4.1 prepared by extracting ghosts with Triton X-100) from 15 patients with hereditary elliptocytosis (HE) were elliptical, which indicates that the primary defect responsible for the abnormal shape of these cells resides in the skeleton. The protein composition of HE skeletons was normal, but in three kindreds purified spectrin heterodimer from 7/7 HE patients was heat sensitive and denatured at 48.0 +/- 0.1 degrees C instead of 49.0 +/- 0.3 degrees C (P less than 0.0005). Heat sensitivity was detected by precipitation and, in the spectrin from one patient, by changes in circular dichroism. In one other kindred spectrin dimer from 3/3 patients denatured at the normal temperature. In two of the three kindreds with heat-sensitive spectrin, intact erythrocytes exhibited budding and fragmentation at the temperature at which spectrin denatured. In the third kindred spectrin was heat sensitive, but erythrocytes were not. The symptoms in the latter kindred were clinically more severe (hemolytic HE with spherocytosis) than in the other three (mild HE). We conclude that defects in the erythrocyte membrane skeleton may be a common feature of HE. As judged by heat denaturation of erythrocytes and purified spectrin dimer, three phenotypically distinct forms of HE exist, two of which are characterized by defective, heat-sensitive spectrin. It remains to be determined whether the molecular defect in spectrin responsible for heat sensitivity is the primary genetic defect responsible for HE.

  20. Middle third fractures of facial skeleton at University Hospital, Kuala Lumpur: a retrospective study.

    PubMed

    Nor, G M; Lian, C B

    1988-12-01

    This is a retrospective study of 80 patients with major central and lateral middle third fractures of facial skeleton treated at University Hospital from 1981 to 1985. The most common was the fractures of zygomatic complex. The peak incidence was in the 20-29 year age group and males were involved more than females (ratio 9: 1). Road traffic accidents were to be blamed for most of the fractures which was 82.25%.