Journal articles: 'Speckle description'

1

Wood, P. R. "Speckle Observations with a Photon Counting Detector." Publications of the Astronomical Society of Australia 6, no. 2 (1985): 120–26. http://dx.doi.org/10.1017/s1323358000017902.

Full text

Abstract:

AbstractA description of the production of astronomical speckles is given in terms of elementary physical principles. Using simple probability arguments, estimâtes are made of signal-to-noise requirements and magnitude limits for détection; data réduction techniques are discussed. A speckle System used on the AAT (Anglo-Australian Télescope) with the IPCS as detector is described.

APA, Harvard, Vancouver, ISO, and other styles

2

Sutton, M., Y. Li, J. D. Brock, and R. E. Thorne. "X-ray intensity fluctuation spectroscopy measurements of the charge density wave phases of NbSe3." Journal de Physique IV 12, no. 9 (November 2002): 3–8. http://dx.doi.org/10.1051/jp4:20020342.

Full text

Abstract:

An introduction to X-ray Intensity Fluctuation Spectroscopy (XIFS) is given by describing its relationship to speckle from coherent sources. A brief description of the relationship of XIFS measurements to the underlying equations of motion is given. Preliminary results for the charge density wave (CDW) system NbSe3 are then presented. Static speckle patterns are shown for the $\overrightarrow {Q}_1 = (0 .76$ 0) CDW peak showing that XIFS experiments are possible in this systom provided time constants are long enough. For electrical currents below threshold, a static speckle pattern is observed but for currents above threshold the speckles are smeared out showing movement of the CDW. It is also shown that above threshold, the longitudinal correlation length decreases.

APA, Harvard, Vancouver, ISO, and other styles

3

Schneider, Jana, Bianca Dauber, Krister Melén, Ilkka Julkunen, and Thorsten Wolff. "Analysis of Influenza B Virus NS1 Protein Trafficking Reveals a Novel Interaction with Nuclear Speckle Domains." Journal of Virology 83, no. 2 (November 5, 2008): 701–11. http://dx.doi.org/10.1128/jvi.01858-08.

Full text

Abstract:

ABSTRACT Many proteins that function in the transcription, maturation, and export of metazoan mRNAs are concentrated in nuclear speckle domains, indicating that the compartment is important for gene expression. Here, we show that the NS1 protein of influenza B virus (B/NS1) accumulates in nuclear speckles and causes rounding and morphological changes of the domains, indicating a disturbance in their normal functions. This property was located within the N-terminal 90 amino acids of the B/NS1 protein and was shown to be independent of any other viral gene product. Within this protein domain, we identified a monopartite importin α binding nuclear localization signal. Reverse-genetic analysis of this motif indicated that nuclear import and speckle association of the B/NS1 protein are required for the full replication capacity of the virus. In the late phase of virus infection, the B/NS1 protein relocated to the cytoplasm, which occurred in a CRM1-independent manner. The interaction of the B/NS1 protein with nuclear speckles may reflect a recruitment function to promote viral-gene expression. To our knowledge, this is the first functional description of a speckle-associated protein that is encoded by a negative-strand RNA virus.

APA, Harvard, Vancouver, ISO, and other styles

4

Hartkopf, William I. "First Results from the New GSU CCD Speckle Camera." Symposium - International Astronomical Union 109 (1986): 301–7. http://dx.doi.org/10.1017/s0074180900076725.

Full text

Abstract:

The CCD speckle camera now in use at Georgia State University has brought about considerable improvement in limiting magnitude and photometric accuracy over the old photographic system, but has also necessitated considerable changes in data storage and reduction. These new data handling techniques are outlined, with a few words about overall accuracy and a brief description of new equipment which should further improve our speckle program at GSU.

APA, Harvard, Vancouver, ISO, and other styles

5

Dilna, Kaitheri Thacharedath, and Duraisamy Jude Hemanth. "Novel image enhancement approaches for despeckling in ultrasound images for fibroid detection in human uterus." Open Computer Science 11, no. 1 (January 1, 2021): 399–410. http://dx.doi.org/10.1515/comp-2020-0140.

Full text

Abstract:

Abstract Ultrasonography is an extensively used medical imaging technique for multiple reasons. It works on the basic theory of echoes from the tissues under consideration. However, the occurrence of signal dependent noise such as speckle destroys utility of ultrasound images. Speckle noise is subject to the composition of image tissue and parameters of image. It reduces the effectiveness of many image processing steps and decreases human perception of fine details form ultrasound images. In many medical image processing methods, despeckling is used as the preprocessing step before segmentation and feature extraction. Many speckle reduction filters are proposed but while combining many techniques some speckle diagnostic information should be preserved. Removal of speckle noise from ultrasound image by preserving edges and added features is a great challenging task in ultrasound image restoration. This paper aims at a comprehensive description and comparison of reduction of speckle noise of ultrasound fibroid image. Many filters are applied on ultrasound scanned images and the performance is marked in terms of some statistical measures. Even though several despeckling filters are there for speckle reduction, all are not good for ultrasound scanned images. A comparison of quality measures such as mean square error, peak signal-to-noise ratio, and signal-to-noise ratio is done in ultrasound images in despeckling.

APA, Harvard, Vancouver, ISO, and other styles

6

Holoubek, Jaroslav, and Josef Baldrian. "Speckle patterns in small angle light scattering: The spatial autocorrelation function." Collection of Czechoslovak Chemical Communications 50, no. 12 (1985): 2873–83. http://dx.doi.org/10.1135/cccc19852873.

Full text

Abstract:

The study deals with the determination of the spatial autocorrelation function of speckle patterns caused by the small-angle light scattering from polymer films. The autocorrelation function determines the shape, size and anisometry of the speckle. The effect of the inner structure and orientation of samples (polypropylene foil, poly(decamethylene terephthalate) and a sample of polypropylene filaments) is discussed; it is shown that under the usual experimental conditions the spatial autocorrelation function of speckle patterns can be determined on the basis of the van Cittert-Zernike theorem of the classical coherence theory. The good agreement between the theoretical and experimental dependences of anisometry, the angular dependence of speckle size and the dependence of speckle size on the sample thickness confirm the suitability of a uniform description based on the classical theory of coherence. From the standpoint of the theory of speckle effect, the results presented in this study allow us to infer that in the light scattering from polymer films under usual conditions the assumptions of the application of the central limit theorem are fulfilled: in the scattering volume there is a sufficient number of scattering units, and path fluctuations due to the scattering foil exceed the wavelength of light.

APA, Harvard, Vancouver, ISO, and other styles

7

Scott, Nicholas J., Steve B. Howell, Elliott P. Horch, and Mark E. Everett. "The NN-explore Exoplanet Stellar Speckle Imager: Instrument Description and Preliminary Results." Publications of the Astronomical Society of the Pacific 130, no. 987 (April 13, 2018): 054502. http://dx.doi.org/10.1088/1538-3873/aab484.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

de Boer, C. R., and F. Kneer. "Speckle Observations of Solar Granulation." Symposium - International Astronomical Union 158 (1994): 398–400. http://dx.doi.org/10.1017/s0074180900108034.

Full text

Abstract:

Image reconstruction by means of speckle interferometry was successfully used to restore the intensity distribution of solar features and to investigate the morphology and dynamics of small-scale structures in active regions of the Sun. The observations were obtained with the Vacuum Tower Telescope (D = 70 cm, f = 46 m) at Observatorio del Teide, Tenerife, on May 17 and 20, 1991, from a plage region close to a sunspot near disc centre. Sequences of bursts consisting of 100 exposures were recorded with a broad-band filter centred at 550 nm (FWHM ≈ 10 nm, diffraction limit 0.2 arcsec). The pickup unit was a video CCD – system with an exposure time of 4 ms and a frame rate of three pictures per second. A description of the observing procedure and of the data handling can be found in de Boer et al. (1992). To obtain the complex Fourier phases speckle masking (Lohmann et al. 1983) was used. The speckle transfer function of the atmosphere was calculated indirectly using Korff's equation (1973). The Fried parameter r0 was estimated with the spectral ratio technique (von der Lühe 1984). This parameter was sometimes as large as 14 cm. With this the theoretical speckle transfer function could be determined for calculating the corrected Fourier amplitudes of the reconstruction. A new low pass filter, based on the reliability of each individual value in the Fourier plane, was applied to the amplitudes to suppress noise at high wavenumbers.

APA, Harvard, Vancouver, ISO, and other styles

9

Jonsson, M., and L. Benckert. "Measurement of residual deformations in butt-welded plates by use of the white light speckle technique." Journal of Strain Analysis for Engineering Design 21, no. 4 (October 1, 1986): 243–46. http://dx.doi.org/10.1243/03093247v214243.

Full text

Abstract:

A method to measure residual deformations in welded plates is presented. An optical technique, called white light speckle, is used to record the released residual deformations. The method is destructive. Two experiments have been performed. The results are compared with corresponding calculated values. A short description of the calculations is given.

APA, Harvard, Vancouver, ISO, and other styles

10

Baldi, Antonio. "A New Analytical Approach for Hole Drilling Residual Stress Analysis by Full Field Method." Journal of Engineering Materials and Technology 127, no. 2 (April 1, 2005): 165–69. http://dx.doi.org/10.1115/1.1839211.

Full text

Abstract:

Most of the full field methods for residual stress investigation combine an optical interferometric technique (grating interferometry, speckle interferometry, holographic interferometry) with the standard hole drilling method. Nowadays many articles describing this kind of approach exist, but most of them focus on the experimental aspects while little attention is devoted to the optimal usage of the huge mass of data that the optical methods make available. This paper, without relying on a specific experimental technique, focuses on the development of a new analytical method that attempts to consistently use all the available data. After a detailed algorithm description, the proposed analysis procedure is tested against numerically generated residual stress fields simulating in-plane speckle interferometry. The results obtained show the reliability and robustness of the algorithm.

APA, Harvard, Vancouver, ISO, and other styles

11

Rodríguez, Paul. "Total Variation Regularization Algorithms for Images Corrupted with Different Noise Models: A Review." Journal of Electrical and Computer Engineering 2013 (2013): 1–18. http://dx.doi.org/10.1155/2013/217021.

Full text

Abstract:

Total Variation (TV) regularization has evolved from an image denoising method for images corrupted with Gaussian noise into a more general technique for inverse problems such as deblurring, blind deconvolution, and inpainting, which also encompasses the Impulse, Poisson, Speckle, and mixed noise models. This paper focuses on giving a summary of the most relevant TV numerical algorithms for solving the restoration problem for grayscale/color images corrupted with several noise models, that is, Gaussian, Salt & Pepper, Poisson, and Speckle (Gamma) noise models as well as for the mixed noise scenarios, such the mixed Gaussian and impulse model. We also include the description of the maximum a posteriori (MAP) estimator for each model as well as a summary of general optimization procedures that are typically used to solve the TV problem.

APA, Harvard, Vancouver, ISO, and other styles

12

Holmes, R. B., K. Hughes, P. Fairchild, B. Spivey, and A. Smith. "Description and simulation of an active imaging technique utilizing two speckle fields: root reconstructors." Journal of the Optical Society of America A 19, no. 3 (March 1, 2002): 444. http://dx.doi.org/10.1364/josaa.19.000444.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Holmes, R. B., K. Hughes, P. Fairchild, B. Spivey, and A. Smith. "Description and simulation of an active imaging technique utilizing two speckle fields: iterative reconstructors." Journal of the Optical Society of America A 19, no. 3 (March 1, 2002): 458. http://dx.doi.org/10.1364/josaa.19.000458.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Zhang, Wanyuan, Tian Zhou, Chao Xu, and Meiqin Liu. "A SIFT-Like Feature Detector and Descriptor for Multibeam Sonar Imaging." Journal of Sensors 2021 (July 15, 2021): 1–14. http://dx.doi.org/10.1155/2021/8845814.

Full text

Abstract:

Multibeam imaging sonar has become an increasingly important tool in the field of underwater object detection and description. In recent years, the scale-invariant feature transform (SIFT) algorithm has been widely adopted to obtain stable features of objects in sonar images but does not perform well on multibeam sonar images due to its sensitivity to speckle noise. In this paper, we introduce MBS-SIFT, a SIFT-like feature detector and descriptor for multibeam sonar images. This algorithm contains a feature detector followed by a local feature descriptor. A new gradient definition robust to speckle noise is presented to detect extrema in scale space, and then, interest points are filtered and located. It is also used to assign orientation and generate descriptors of interest points. Simulations and experiments demonstrate that the proposed method can capture features of underwater objects more accurately than existing approaches.

APA, Harvard, Vancouver, ISO, and other styles

15

Henao, Rodrigo, John Fredy Barrera, and Roberto Torroba. "Stokes Parameters Description for the Contrast Variations Observed in Fringes Generated by Digital Speckle Correlation." Journal of Holography and Speckle 1, no. 2 (June 1, 2004): 85–89. http://dx.doi.org/10.1166/jhs.2004.012.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Maksimov, A. F., Yu Yu Balega, V. V. Dyachenko, E. V. Malogolovets, D. A. Rastegaev, and E. A. Semernikov. "The EMCCD-based speckle interferometer of the BTA 6-m telescope: Description and first results." Astrophysical Bulletin 64, no. 3 (July 2009): 296–307. http://dx.doi.org/10.1134/s1990341309030092.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Horch, Elliott P., Daniel R. Veillette, Roberto Baena Gallé, Sagar C. Shah, Grant V. O'Rielly, and William F. van Altena. "OBSERVATIONS OF BINARY STARS WITH THE DIFFERENTIAL SPECKLE SURVEY INSTRUMENT. I. INSTRUMENT DESCRIPTION AND FIRST RESULTS." Astronomical Journal 137, no. 6 (May 6, 2009): 5057–67. http://dx.doi.org/10.1088/0004-6256/137/6/5057.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Cluydts, C., and W. De Waele. "Realisation of micro-speckle patterns for digital image correlation on dental implants." International Journal Sustainable Construction & Design 3, no. 1 (November 6, 2012): 1–7. http://dx.doi.org/10.21825/scad.v3i1.20550.

Full text

Abstract:

In vitro experiments and finite element analyses can be used to investigate the mechanicalperformance of dental implant structures. But before experimental and mechanical evaluations can becarried out, the right material properties, test methods and measurement techniques should be pointed out.The material properties of dental implants and characteristics of the jaw bone are widely documented.Concerning the right experimental setup and measurement techniques no conclusive description is given.Digital Image Correlation (DIC) is currently a widespread method. It uses random speckle patterns that arecorrelated to accurately measure displacement and strains of 3D-structures. If accurate results arepursued, first a thorough optimisation of this measuring technique must be accomplished. The choices aremade based on the expected effect of load application on a dental implant. In literature the expecteddisplacements are quite small, magnitude 100µm, which requires high accuracy measurements. Thepossibilities of using DIC on micro-scale for titanium components is discussed in this paper.

APA, Harvard, Vancouver, ISO, and other styles

19

WANG, JING, ZHOU SHI, MATTHIEU DAVY, and AZRIEL Z. GENACK. "WAVE PROPAGATION AND LOCALIZATION VIA QUASI-NORMAL MODES AND TRANSMISSION EIGENCHANNELS." International Journal of Modern Physics: Conference Series 11 (January 2012): 1–11. http://dx.doi.org/10.1142/s2010194512006113.

Full text

Abstract:

Field transmission coefficients for microwave radiation between arrays of points on the incident and output surfaces of random samples are analyzed to yield the underlying quasi-normal modes and transmission eigenchannels of each realization of the sample. The linewidths, central frequencies, and transmitted speckle patterns associated with each of the modes of the medium are found. Modal speckle patterns are found to be strongly correlated leading to destructive interference between modes. This explains distinctive features of transmission spectra and pulsed transmission. An alternate description of wave transport is obtained from the eigenchannels and eigenvalues of the transmission matrix. The maximum transmission eigenvalue, τ1 is near unity for diffusive waves even in turbid samples. For localized waves, τ1 is nearly equal to the dimensionless conductance, which is the sum of all transmission eigenvalues, g = Στn. The spacings between the ensemble averages of successive values of ln τn are constant and equal to the inverse of the bare conductance in accord with predictions by Dorokhov. The effective number of transmission eigenvalues Neff determines the contrast between the peak and background of radiation focused for maximum peak intensity. The connection between the mode and channel approaches is discussed.

APA, Harvard, Vancouver, ISO, and other styles

20

Seif, M. A., P. J. Mohr, F. A. Moslehy, and S. L. Rice. "Deformation and Strain Fields in Pin Specimens in Sliding Contact by Laser Speckle and Metallographic Techniques." Journal of Tribology 112, no. 3 (July 1, 1990): 506–13. http://dx.doi.org/10.1115/1.2920287.

Full text

Abstract:

This paper describes the application of laser speckle photography to the measurement of deformations associated with sliding wear. The deformations and the associated strains are those which occur on the “side” of a rectangular-sectioned pin which is in sliding contact against a counterface disc. The side of the pin is exposed to a pulsed ruby laser beam, and a double exposure specklegram is made to record deformations which occur between laser pulses. Strain fields are obtained from displacement data by use of the Lagrangian description, and neglecting out-of-plane displacement gradients. By appropriately sequencing pulses, deformation histories can be obtained, in situ. And since the exposed side of the thin pin specimen represents the “cover” layer under which subsurface sections lie, the deformation history observable through the laser speckle method reflects the deformation behavior which is occurring on subsurface planes. By post-test metallography on planes close to this side face, the degree of correspondence between surface and subsurface deformation fields is demonstrated. The paper discusses the materials, apparatus and experimental techniques employed, and presents results obtained with several metallic specimens. Of particular interest is the extent of the plastically deformed subsurface zone, and its development as a function of time.

APA, Harvard, Vancouver, ISO, and other styles

21

Knudsen, Kristine, Joergen Thorup, Rune Strandby, Rikard Ambrus, Linea Ring, and Inge Ifaoui. "Laser Speckle Contrast Imaging to Evaluate Bowel Lesions in Neonates with NEC." European Journal of Pediatric Surgery Reports 05, no. 01 (January 2017): e43-e46. http://dx.doi.org/10.1055/s-0037-1606196.

Full text

Abstract:

Background Necrotizing enterocolitis (NEC) is the most frequent surgical emergency in newborns. Intestinal ischemia is considered a factor that precedes the development of NEC lesions. Laser speckle contrast imaging (LSCI) can be used to assess tissue microcirculation. We evaluated if LSCI may help to detect intestinal regions with reduced microcirculation in NEC. Case Report A male patient (gestational age, 26 [3/7] weeks; birth weight, 600 g) showed clinical signs of NEC 28 days after birth. X-ray revealed pneumatosis intestinalis and portal gas. Laparotomy showed NEC lesions with signs of transmural ischemia in the terminal ileum and cecum. Surgical resection lines (RLs) were marked, followed by LSCI measurements and resection of the bowel between the two RLs. Post hoc LSCI analyses were conducted on both sides of the proximal and distal RL. Low-flux values, indicating reduced microcirculation, were found in the macroscopically assessed necrotic bowel at the proximal RL, whereas higher flux values, indicating sufficient microcirculation, were found in the macroscopically assessed normal bowel. Discussion This study is the first description of intra-abdominal use of LSCI to evaluate tissue microcirculation in relation to NEC lesions. LSCI could be a valuable tool to distinguish between ischemic and nonischemic bowel in neonates undergoing surgery for NEC.

APA, Harvard, Vancouver, ISO, and other styles

22

Reeves, M., N. Taylor, C. Edwards, D. Williams, and C. H. Buckberry. "A study of brake disc modal behaviour during squeal generation using high-speed electronic speckle pattern interferometry and near-field sound pressure measurements." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 214, no. 3 (March 1, 2000): 285–96. http://dx.doi.org/10.1243/0954407001527420.

Full text

Abstract:

The out-of-plane surface vibration of a brake disc during naturally excited squeal has been investigated using a combination of high-speed electronic speckle pattern interferometry (ESPI) and near-field sound pressure measurements. Both techniques provide visualization and quantification of the time-resolved surface velocity. A mathematical description of disc brake squeal modal behaviour is proposed that predicts accurately all of the experimentally observed interferometry and sound field measurements. The complex mode description proposed here is in agreement with that proposed by others for drum brake squeal. This assumes that two identical diametral modes are excited simultaneously, identical except for a spatial and temporal phase shift. The use of a near-field microphone array provided a convenient multipoint, non-contacting vibration probe which may find use in the study of other vibrations characterized by high surface amplitudes and efficient sound radiation. The high-speed ESPI provided a real-time visualization of surface deformation analogous to double- pulsed holographic interferometry, with the benefit of giving a true time series of the surface deformation during a single vibration cycle.

APA, Harvard, Vancouver, ISO, and other styles

23

Ivanov, S. I., and M. N. Alekhin. "Myocardial work in assessment of left ventricular systolic function." Kardiologiia 60, no. 3 (May 3, 2020): 80–88. http://dx.doi.org/10.18087/cardio.2020.3.n925.

Full text

Abstract:

This review focuses on a new method for noninvasive, complex evaluation of left ventricular (LV) systolic function using an echocardiography-based technology of computing indexes of myocardial performance by construction of pressure-deformation curves. Since this new method accounts for the effect of afterload on myocardial contractility, the article presents data demonstrating advantages of the evaluation of LV myocardial performance over the speckle-tracking echocardiography and other methods in diagnostics of several diseases. The review provides a description of this method and its advantages and limitations. The authors analyzed results of major studies on evaluation of LV performance. Prospects of implementation and practical use of the method are discussed in the aspects of diagnostics of cardiovascular diseases and risk stratification for different groups of patients.

APA, Harvard, Vancouver, ISO, and other styles

24

Liu, Ming, Shichao Chen, Fugang Lu, and Junsheng Liu. "Product Dictionary Learning-Based SAR Target Configuration Recognition." International Journal of Antennas and Propagation 2020 (March 16, 2020): 1–8. http://dx.doi.org/10.1155/2020/9704829.

Full text

Abstract:

Dictionary construction is a key factor for the sparse representation- (SR-) based algorithms. It has been verified that the learned dictionaries are more effective than the predefined ones. In this paper, we propose a product dictionary learning (PDL) algorithm to achieve synthetic aperture radar (SAR) target configuration recognition. The proposed algorithm obtains the dictionaries from a statistical standpoint to enhance the robustness of the proposed algorithm to noise. And, taking the inevitable multiplicative speckle in SAR images into account, the proposed algorithm employs the product model to describe SAR images. A more accurate description of the SAR image results in higher recognition rates. The accuracy and robustness of the proposed algorithm are validated by the moving and stationary target acquisition and recognition (MSTAR) database.

APA, Harvard, Vancouver, ISO, and other styles

25

Galland, Frédéric, Nicolas Bertaux, and Philippe Réfrégier. "Multi-component image segmentation in homogeneous regions based on description length minimization: Application to speckle, Poisson and Bernoulli noise." Pattern Recognition 38, no. 11 (November 2005): 1926–36. http://dx.doi.org/10.1016/j.patcog.2004.10.002.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Jensen, Jørgen Arendt. "Deconvolution of Ultrasound Images." Ultrasonic Imaging 14, no. 1 (January 1992): 1–15. http://dx.doi.org/10.1177/016173469201400101.

Full text

Abstract:

Based on physical models, it is indicated that the received pressure field in ultrasound B-mode images can be described by a convolution between a tissue reflection signal and the emitted pressure field. This result is used in a description of current image formation and in formulating a new processing scheme. The suggested estimator can take into account the dispersive attenuation, the temporal and spatial variation of the pulse, and the change in reflection strength and signal-to-noise ratio. Details of the algorithm and the estimation of parameters to be used are given. The performance is indicated by two examples. One is for a synthetic signal and the other is for data measured from a tissue mimicking phantom. The last example shows a finer speckle pattern, giving an increased resolution.

APA, Harvard, Vancouver, ISO, and other styles

27

Chelini, Virginie, Sébastien Hascoët, Franck Thuny, Jean Francois Avierinos, Didier Carrié, Michel Galinier, Yvan Le Dolley, Adrien Salem, and Gilbert Habib. "095: Segmental and global peak systolic longitudinal strain using speckle myocardial echocardiography in isolated left ventricular noncompaction. Description of 28 cases." Archives of Cardiovascular Diseases Supplements 5, no. 1 (January 2013): 31. http://dx.doi.org/10.1016/s1878-6480(13)71025-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Li, L., H. Yang, Q. Chen, and X. Liu. "A STATISTICAL TEXTURE FEATURE FOR BUILDING COLLAPSE INFORMATION EXTRACTION OF SAR IMAGE." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3 (April 30, 2018): 871–76. http://dx.doi.org/10.5194/isprs-archives-xlii-3-871-2018.

Full text

Abstract:

Synthetic Aperture Radar (SAR) has become one of the most important ways to extract post-disaster collapsed building information, due to its extreme versatility and almost all-weather, day-and-night working capability, etc. In view of the fact that the inherent statistical distribution of speckle in SAR images is not used to extract collapsed building information, this paper proposed a novel texture feature of statistical models of SAR images to extract the collapsed buildings. In the proposed feature, the texture parameter of G0 distribution from SAR images is used to reflect the uniformity of the target to extract the collapsed building. This feature not only considers the statistical distribution of SAR images, providing more accurate description of the object texture, but also is applied to extract collapsed building information of single-, dual- or full-polarization SAR data. The RADARSAT-2 data of Yushu earthquake which acquired on April 21, 2010 is used to present and analyze the performance of the proposed method. In addition, the applicability of this feature to SAR data with different polarizations is also analysed, which provides decision support for the data selection of collapsed building information extraction.

APA, Harvard, Vancouver, ISO, and other styles

29

Maddox, Paul, Aaron Straight, Peg Coughlin, Timothy J. Mitchison, and Edward D. Salmon. "Direct observation of microtubule dynamics at kinetochores in Xenopus extract spindles." Journal of Cell Biology 162, no. 3 (August 4, 2003): 377–82. http://dx.doi.org/10.1083/jcb.200301088.

Full text

Abstract:

Microtubule plus ends dynamically attach to kinetochores on mitotic chromosomes. We directly imaged this dynamic interface using high resolution fluorescent speckle microscopy and direct labeling of kinetochores in Xenopus extract spindles. During metaphase, kinetochores were stationary and under tension while plus end polymerization and poleward microtubule flux (flux) occurred at velocities varying from 1.5–2.5 μm/min. Because kinetochore microtubules polymerize at metaphase kinetochores, the primary source of kinetochore tension must be the spindle forces that produce flux and not a kinetochore-based mechanism. We infer that the kinetochore resists translocation of kinetochore microtubules through their attachment sites, and that the polymerization state of the kinetochore acts a “slip-clutch” mechanism that prevents detachment at high tension. At anaphase onset, kinetochores switched to depolymerization of microtubule plus ends, resulting in chromosome-to-pole rates transiently greater than flux. Kinetochores switched from persistent depolymerization to persistent polymerization and back again during anaphase, bistability exhibited by kinetochores in vertebrate tissue cells. These results provide the most complete description of spindle microtubule poleward flux to date, with important implications for the microtubule–kinetochore interface and for how flux regulates kinetochore function.

APA, Harvard, Vancouver, ISO, and other styles

30

Denker, Carsten, and Alexandra Tritschler. "Mini-filaments – small-scale analogues of solar eruptive events?" Proceedings of the International Astronomical Union 4, S259 (November 2008): 223–24. http://dx.doi.org/10.1017/s1743921309030476.

Full text

Abstract:

AbstractMini-filaments are a small-scale phenomenon of the solar chromosphere, which frequently occur across the entire disk (see e.g. Wang, Li, Denker, et al. 2000). They share a variety of characteristics with their larger-scale cousins and may serve as a proxy for more complex systems. They play an important role in the energy and mass supply to the corona. In the case of small-scale eruptive filaments, only a single, small-scale loop system is involved. Furthermore, they are supported by simple magnetic field configurations (see Livi, Wang & Martin 1985), either magnetic bipoles or well-defined multipoles, easing their theoretical description. Since mini-filaments are small (just a few tens of seconds of arc) but highly dynamic (eruptions can occur within just a few minutes), they are an ideal target for high-resolution two-dimensional spectroscopy. We present a preliminary analysis of two-dimensional Hα spectroscopic data accompanied by broad-band speckle-restored images to demonstrate that chromospheric small-scale phenomena can serve as building blocks for our understanding of solar eruptive events such as filament/prominence eruptions and even coronal mass ejections (CMEs).

APA, Harvard, Vancouver, ISO, and other styles

31

Pilch, Alan, Ajay Mahajan, and Tsuchin Chu. "Measurement of Whole-Field Surface Displacements and Strain Using a Genetic Algorithm Based Intelligent Image Correlation Method." Journal of Dynamic Systems, Measurement, and Control 126, no. 3 (September 1, 2004): 479–88. http://dx.doi.org/10.1115/1.1789968.

Full text

Abstract:

This paper presents an intelligent digital image correlation technique that uses genetic algorithms to measure surface displacements and strains. Speckle patterns are spray painted on the surface of interest and pictures taken before and during loading. Subpixel resolution, required for measuring displacements and strains accurately, is obtained by using interpolation methods. An innovative procedure based on genetic algorithms (GA) is used that has the potential to give the two displacements and four deformation gradients directly for a subset being investigated. This paper presents the algorithm for the six variables, but uses only the displacements (two variables) to calculate the 2-D strain fields. The genetic algorithms can guarantee a solution based on a comprehensive calibration procedure. The focus of this paper is the description of the GA routine used for the search process as well as the calibration scheme. Measurement results are presented for rigid-body displacement, 1-D and 2-D strain as proof of concept. Some potential applications for this work are to extract surface displacements and strains on the surfaces of aircraft, spacecraft and reusable launch vehicles, submarine and ship hulls, civil infrastructures such as bridges, dams and buildings, and biomedical imaging applications.

APA, Harvard, Vancouver, ISO, and other styles

32

Lv, Xiangfeng, Yahan Yang, Yan Chen, Nianjin Wang, Min Yang, Ying Shao, and Jiaxing Li. "Experimental Study on the Relationship between Compression Stability and Deformation Localization of Viscous/Brittle Rock-Like Materials." Advances in Materials Science and Engineering 2021 (August 5, 2021): 1–11. http://dx.doi.org/10.1155/2021/7153661.

Full text

Abstract:

Rock-like materials often exhibit irregular failure deformation under long-term service conditions, and the deformation and failure of asphalt and concrete materials is a serious problem that leads to subgrade failure. In this study, two different viscous/brittle rock-like materials were prepared by the in situ loading and optical speckle synchronous monitoring test method, and the evolution characteristics of the deformation field were studied during compression. The formation process of the compression deformation localization of rock-like materials and their relationship with stability were analyzed. A quantitative description of the compression deformation stage and localization characteristics of the viscous/brittle rock-like materials is presented. The results can be summarized as follows. At the initial stage of compression, the deformation localization zone of viscous/brittle rock-like materials begins to expand from the middle area to the surrounding area. Preliminary results of the deformation localization of the linear elastic deformation stage were obtained. The failure cloud image is completely formed at the peak, which is consistent with the failure physical map. The deformation process of compression can be quantitatively described using the deformation localization characteristics of rock-like materials.

APA, Harvard, Vancouver, ISO, and other styles

33

Müller, Ulrich, Andreas Ringhofer, Reinhard Brandner, and Gerhard Schickhofer. "Homogeneous shear stress field of wood in an Arcan shear test configuration measured by means of electronic speckle pattern interferometry: description of the test setup." Wood Science and Technology 49, no. 6 (July 21, 2015): 1123–36. http://dx.doi.org/10.1007/s00226-015-0755-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Henry, Todd J., and Donald W. McCarthy. "The Murky Depths of the Main Sequence: Nearby Speckled Dwarfs and Elusive Brown Beasts." International Astronomical Union Colloquium 135 (1992): 10–20. http://dx.doi.org/10.1017/s0252921100006060.

Full text

Abstract:

AbstractUsing infrared speckle imaging techniques, we have completed a comprehensive survey of all northern (δ ≥ −25°) M dwarfs within 8 parsecs for low mass companions. Of the 74 targets searched, six new companions were found. Included in the final census are four objects orbiting their primaries at sub-arcsecond separations which have masses near 80 Jupiters, making them viable brown dwarf candidates. Three of these — LHS 1047B, GL 623B and G 208-44B — are the faintest red objects for which masses have been determined and represent the limit of our current knowledge about the faint end of the mass-luminosity relation.The complete sample includes 99 members, and under further analysis reveals fundamental facts about the red dwarf population that were unknown until the present study: 1) 30-40 % of M dwarf primaries have companions, 2) more companions are found orbiting 1-10 AU from the primary than in any other decade interval, and 3) there are 50% fewer red dwarfs known in the more distant half of the survey volume, presumably because the parallax and proper motion surveys are incomplete.In addition, we find that the infrared luminosity function (LF) is fiat or rising toward the end of the main sequence, while the visible LF may be flat, and we illustrate that the determination of an accurate LF is critically sensitive to the resolution of binaries. A better description of the stellar population, the mass function, is found to be undoubtedly rising to the stellar/substellar break. Finally, we have developed a much-needed mass-luminosity relation for stars of mass 1.2 to 0.08 M⊙, and using these relations find that the M dwarfs contribute ~0.2 M⊙/pc3 to the galactic mass.

APA, Harvard, Vancouver, ISO, and other styles

35

Tarquis, A. M., A. Platonov, A. Matulka, J. Grau, E. Sekula, M. Diez, and J. M. Redondo. "Application of multifractal analysis to the study of SAR features and oil spills on the ocean surface." Nonlinear Processes in Geophysics 21, no. 2 (March 28, 2014): 439–50. http://dx.doi.org/10.5194/npg-21-439-2014.

Full text

Abstract:

Abstract. The use of synthetic aperture radar (SAR) to investigate the ocean surface provides a wealth of useful information that is very seldom used to its full potential. Here we will discuss the application of multifractal techniques to detect oil spills and the dynamic state of the sea regarding turbulent diffusion. We present different techniques in order to relate the shape of the multifractal spectral functions and the maximum fractal dimension to the behaviour of the ocean surface. We compare eddy and sheared dominated flows with convective driven flows and discuss the different features and observation methods. We also compare the scaling of different oil spills detected by means of SAR images. Recent spills and weathered ones are selected and compared to investigate their behaviour in different spatial and temporal ranges. We calculate the partition function based on the grey intensity value of each SAR pixel deriving several types of multifractal spectra as a function of spill residence time estimated for each image. Image manipulations are seen to reduce the speckle noise and thus distinguish much better the texture of the oil spill images. The results are used to discuss how eddy diffusivity may be estimated and used in a description of the ocean surface using a simple turbulence kinematic simulation model to predict the shape of oil spills. Differences in the multifractal spectrum among SAR images may detect the slicks due to plankton and also provide information on the age of the oil spills, on the Lagrangian turbulent structure and on ocean surface diffusivity.

APA, Harvard, Vancouver, ISO, and other styles

36

Eleonsky, S. I., Yu G. Matvienko, V. S. Pisarev, and A. V. Chernov. "Damage accumulation near a hole under low cycle fatigue proceeding from measurements of local deformation response." Industrial laboratory. Diagnostics of materials 86, no. 10 (October 14, 2020): 46–55. http://dx.doi.org/10.26896/1028-6861-2020-86-10-46-55.

Full text

Abstract:

A new destructive method for quantitative determination of the damage accumulation in the vicinity of a stress concentrator has been proposed and verified. Increase of damage degree in local area with a high level of the strain gradient was achieved through preliminary low-cycle pull-push loading of plane specimens with central open holes. The above procedure is performed for three programs at the same stress range (333.3 MPa) and different stress ratio values 0.33, – 0.66 and – 1.0, and vice versa for two programs at the same stress ratio – 0.33 and different stress range 333.3 and 233.3 MPa. This process offers a set of the objects to be considered with different degree of accumulated fatigue damages. The key point of the developed approach consists in the fact that plane specimens with open holes are tested under real operation conditions without a preliminary notching of the specimen initiating the fatigue crack growth. The measured parameters necessary for a quantitative description of the damage accumulation process were obtained by removing the local volume of the material in the form of a sequence of narrow notches at a constant level of external tensile stress. External load can be considered an amplifier enhancing a useful signal responsible for revealing the material damage. The notch is intended for assessing the level of fatigue damage, just as probe holes are used to release residual stress energy in the hole drilling method. Measurements of the deformation response caused by local removing of the material are carried out by electronic speckle-pattern interferometry at different stages of low-cycle fatigue. The transition from measured in-plane displacements to the values of the stress intensity factor (SIF) and the T-stress was carried out on the basis of the relations of linear fracture mechanics. It was shown that the normalized dependences of the stress intensity factor on the durability percentage for the first notch (constructed for four programs of cyclic loading with different parameters), reflect the effect of the stress ratio and stress range of the loading cycle on the rate of damage accumulation. The data were used to obtain the explicit form of the damage accumulation function that quantitatively describes damage accumulation process. The functions were constructed for different stress ratios and stress ranges.

APA, Harvard, Vancouver, ISO, and other styles

37

Ткач, Михаил Романович, Сергей Борисович Кулишов, Виталий Анатольевич Полищук, Владимир Сергеевич Ключник, Юрий Григорьевич Золотой, Ирина Юрьевна Жук, Аркадий Юрьевич Проскурин, and Юрий Николаевич Галынкин. "Экспериментально-расчетное определение механических свойств материала рабочих лопаток ГТД." Aerospace technic and technology, no. 4sup1 (August 27, 2021): 83–92. http://dx.doi.org/10.32620/aktt.2021.4sup1.12.

Full text

Abstract:

A schematic description of a stand based on a digital speckle interferometer with a diffuse reference wave is given, which makes it possible to determine the natural frequencies and vibration modes of the blades in real-time. In the frequency range of 100 ... 3000 Hz, an experimental study of the vibration characteristics of a turbine rotor blade of a gas turbine engine was carried out, under free boundary conditions, which were achieved by placing the blade on soft silicone racks. Blade dimensions: height along the trailing edge - 288 mm, a chord in the middle section - 88.5 mm. 7 modes of vibrations have been identified. The technology of creating a solid-state geometric model of a rotor blade based on a faceted body obtained by 3D scanning with an accuracy of 0.01 mm is presented. The finite element method, using the Lagrange variation principle, is used to calculate the values of natural frequencies and vibration modes of a blade based on the developed geometric model. Concerning the frequency range 100 ... 3000 Hz, using the Ansys Workbench software package, a series of calculations of the resonant frequencies of the blade, by the finite element method, in the range of variation of the values of mechanical properties was carried out: Young's modulus E = 200 ... 230 GPa; Poisson's ratio μ = 0.26 ... 0.3. The density of the material: ρ = 7830 kg / m³, determined experimentally, by the method of hydrostatic weighing. The final element used in the calculation is (tetrahedron) SOLID 187; the minimum element size is 0.6 mm. The total number of elements is about 1.5 ∙ 10⁶. Based on the two-dimensional spline interpolation of the calculated data, the dependence of the standard deviation of the calculated and experimental values on the adopted mechanical properties of the material of the rotor blade is built. In the range of values E = 215 ... 217 GPa and μ = 0.295 ... 0.3, the minimum standard deviation of the calculated frequencies from their experimental values is 0.73%. Provided the value of the standard deviation of frequencies is 1%, the range of values of mechanical properties will be: E = 211 ... 220 GPa and μ = 0.26 ... 0.3. It is shown that narrowing the studied range of values of Young's modulus and Poisson's ratio does not significantly affect the results obtained.

APA, Harvard, Vancouver, ISO, and other styles

38

Ellingson, Robert G., and Warren J. Wiscombe. "The Spectral Radiance Experiment (SPECTRE): Project Description and Sample Results." Bulletin of the American Meteorological Society 77, no. 9 (September 1996): 1967–85. http://dx.doi.org/10.1175/1520-0477(1996)077<1967:tsrepd>2.0.co;2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

ERDOĞAN-DERELI, DENIZ, MELIH ERTAN ÇINAR, and ERTAN DAĞLI. "Cirrophorus species (Annelida: Polychaeta: Paraonidae) in the Sea of Marmara, with description of a new species." Zootaxa 4347, no. 1 (November 10, 2017): 137. http://dx.doi.org/10.11646/zootaxa.4347.1.8.

Full text

Abstract:

This paper deals with specimens of Cirrophorus collected from the depths ranging from 3 to 500 m in 2012 and 2013 in the Sea of Marmara, Turkey. Among the material, one new species and two already known species were found. The new species is mainly characterized by having long and clavate notopodial postchaetal lobes in the branchial region; red speckles near nuchal organs; and a very long branch of lyrate chaetae (4 times longer than the shorter one). A recently described species, Cirrophorus nikebianchii, was found at the majority of soft-bottom stations. All species found in the area were described and discussed.

APA, Harvard, Vancouver, ISO, and other styles

40

White, R. J., and L. Winokur. "Quantitative description and discrimination of butterfly wing patterns using moment invariant analysis." Bulletin of Entomological Research 93, no. 4 (July 2003): 361–76. http://dx.doi.org/10.1079/ber2003242.

Full text

Abstract:

AbstractStudies examining and using pattern variation in insects for identification and characterization of individuals and populations have been limited by the methods available for quantifying wing patterns objectively. In this paper, differences in wing pattern are demonstrated statistically using moment invariant data sets generated automatically from digitized images of the speckled wood butterfly, Pararge aegeria (Linnaeus). Studies with other biological subjects have already shown moment invariants to work well with outline shapes and silhouettes. A pilot study with replicated monochrome photographs of a single butterfly showed the method could detect pattern differences between wing surfaces, even in the presence of simulated wing fading and damage. In a further study of the wings of 228 specimens, multivariate analyses of variance using the moment data reliably detected differences between groups of butterflies according to sex, geographical origin and culture history. Potential applications and future improvements of the moment methodology are considered.

APA, Harvard, Vancouver, ISO, and other styles

41

PUTZKE, JAIR, and ANTONIO B. PEREIRA. "Phaeosphaeria deschampsii (Ascomycota): A new parasite species of Deschampsia antarctica (Poaceae) described to Antarctica." Anais da Academia Brasileira de Ciências 88, no. 3 suppl (August 18, 2016): 1967–69. http://dx.doi.org/10.1590/0001-3765201620150779.

Full text

Abstract:

ABSTRACT This study presents the description of Phaeosphaeria deschampsii, which was found in plant communities from Half Moon Island, South Shetland Archipelago, Antarctica, in February 2014. Many patches of Deschampsia antarctica (Poaceae), the only indigenous Poaceae specie in Antarctic, were found dead, parasitized by a fungi pathogen. Based on the shape of its perithecia, with oblique neck, erumpent in the grass tissues, ascospore form and septation, the specie was identified as new to science.

APA, Harvard, Vancouver, ISO, and other styles

42

Cho, David, Craig Coulombe, Scott McLaren, Kevin Johnson, and Gary F. Margrave. "Fractured shale description using isotropic seismic analysis." Interpretation 1, no. 2 (November 1, 2013): T199—T209. http://dx.doi.org/10.1190/int-2012-0008.1.

Full text

Abstract:

Direct methods for fracture detection using P-wave seismic data typically require an azimuthal analysis of the reflected wavefield. However, conventional data acquisition practices often lack sufficient azimuthal coverage for proper application of these techniques. In such cases, alternative methods become necessary. We investigated the use of subsurface properties estimated from seismic data under isotropic assumptions to delineate fracture systems in the Second White Speckled Shale of Alberta, Canada. We implemented two methodologies for fracture detection. (1) Using seismic attributes sensitive to the structure of the seismic image, structural changes such as folds were identified, from which the associated fracture systems can be inferred. (2) For fractures not directly correlated to such structural changes, analysis of the effective elastic properties of fractured media proved useful. In particular, failure criteria and effective-medium theories were used to investigate fracture phenomena and their corresponding seismic response. Using standard isotropic inversion techniques, estimates of reservoir elastic properties were derived. Subsequently, an interpretation of these results was conducted through consideration of anisotropic models. Specifically, low values of Poisson’s ratio were interpreted as more favorable conditions for fracturing and low values of Young’s modulus and vertical P-wave velocity were interpreted as direct indicators for the presence of fractures. The structural analysis identified a subtle fold where fracturing in its vicinity can be inferred. Furthermore, investigation into the elastic properties of fractured media revealed locations on the flanks of the fold that were likely to be fractured, providing an indication of the lateral extent of fracturing that was not possible from structural attributes alone. The combined interpretation of these results suggested the existence of a contractional fault-bend fold, where an area at the crest of the fold did not appear to contain fractures, corresponding to the undeformed zone as predicted by structural models of fault-bend folding.

APA, Harvard, Vancouver, ISO, and other styles

43

Lega, J. C., C. Estublier, V. Cottin, N. Fabien, D. Vital Durand, and I. Durieu. "Description de spectre clinique du syndrome des antisynthétases : une approche méta-analytique." La Revue de Médecine Interne 33 (December 2012): A70—A71. http://dx.doi.org/10.1016/j.revmed.2012.10.094.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Zubov, A. S., and A. Yu Titarenko. "A new subspecies of Chrysochroa margotana Novak, 1992 (Coleoptera, Buprestidae) from Myanmar." Acta Biologica Sibirica 5, no. 2 (June 17, 2019): 5–16. http://dx.doi.org/10.14258/abs.v5.i2.5783.

Full text

Abstract:

The paper provides the description of a new subspecies of Chrysochroa margotana Novak, 1992 from Burma and restoration of C. margotana Novak, 1992 as a valid specie name as a result of morphological analysis of close species from subgenus Chrooxantha, group mniszechi (Holynski, 2009).

APA, Harvard, Vancouver, ISO, and other styles

45

Rocha, Agda Alves, and Edilberto Giannotti. "External Morphology of Immatures of Mischocyttarus nomurae Richards (Hymenoptera, Vespidae) during the Post-embryonic Development." Sociobiology 63, no. 3 (October 25, 2016): 998. http://dx.doi.org/10.13102/sociobiology.v63i3.988.

Full text

Abstract:

The work on this paper aimed to perform the description of the immatures and determine the number of larval instars in the post-embryonic development of Mischocyttarus nomurae Richards, a social wasp which the only works performed were the description of the specie and of the male. Twenty colonies were collected in the city of Rio de Contas, in the region of the Chapada Diamantina, Bahia, Brazil and there were dimensioned 145 eggs, 349 larvae, 12 pre-pupae and 59 pupae. The eggs presented an average length of 1.03 ± 0.12mm and diameter of 0.40 ± 0.03mm. The average rate of growth of the larvae that presented five instars was 1.49. The width of the cephalic capsule of the larvae was: 1st instar 0.32 ± 0.08, 2nd instar 0.54 ± 0.06, 3rd instar 0.77 ± 0.07, 4th instar 1.05 ± 0.10 and 5th instar 1.55 ± 0.07. The average width of the larvae of 5th instar and pre-pupae were close, where larvae of the 1st instar differed from the egg, being smaller. The average measure of the pupae was 1.85 ± 0.08. The specie presents two abdominal lobes highly projected towards and the first thoracic spiracle is 3.1 times higher than the second one. This is the first work on the biology of the specie.

APA, Harvard, Vancouver, ISO, and other styles

46

SIGURA, AUDE, and JEAN-LOU JUSTINE. "Monogeneans of the speckled blue grouper, Epinephelus cyanopodus (Perciformes, Serranidae), from off New Caledonia, with a description of four new species of Pseudorhabdosynochus and one new species of Laticola (Monogenea: Diplectanidae), and evidence of monogenean faunal changes according to the size of fish." Zootaxa 1695, no. 1 (February 1, 2008): 1. http://dx.doi.org/10.11646/zootaxa.1695.1.1.

Full text

Abstract:

Nine species were identified among 1500 monogeneans collected on the gills of 17 speckled blue groupers, Epinephelus cyanopodus, caught off New Caledonia, South Pacific. A new method for describing squamodiscs in tables is proposed. Diplectanids included one new species of Laticola, which was the most abundant species, and six species of Pseudorhabdosynochus, including four new species, which were differentiated mainly on the basis of morphology of the sclerotised vagina. Laticola cyanus n. sp. is characterised by its genital organs. Pseudorhabdosynochus cyanopodus n. sp. and P. podocyanus n. sp. both have a vagina with a large primary chamber. Pseudorhabdosynochus chauveti n. sp. has a vagina with a long, coiled primary canal. Pseudorhabdosynochus exoticus n. sp. has an aberrant discoid vagina and characters (tip of quadriloculate organ, lateral bar with hook), which differentiate it from all other species. The fivepreviously cited species are strictly specific to E. cyanopodus and were abundant in large (>585 mm) fish. In addition, Haliotrema sp. (Ancyrocephalidae) and Allobenedenia sp. (Capsalidae), both undescribed, were also found on large fish. Pseudorhabdosynochus duitoe Justine, 2007 and P. huitoe Justine, 2007, were collected in very small numbers, mainly in young (345–500 mm) fish; the type-host of these two species is the highfin grouper, E. maculatus, and their occurrence on E. cyanopodus was considered accidental and due to habitat overlap between the young speckled blue groupers and adult highfin groupers. It is hypothesized that the speckled blue groupers are infested by their own, strictly specific monogeneans, only when they encounter older members of their species during spawning aggregations. Spawning aggregations thus play a key role in infestation of coral reef fish by their monoxenic parasites such as monogeneans. Lists are given for other parasites of the speckled blue grouper, including digeneans, cestodes, nematodes, isopods and copepods, with new records from New Caledonia: 41 species of parasites are recorded.

APA, Harvard, Vancouver, ISO, and other styles

47

NGUYEN, LUAN THANH, NIKOLAY A. JR POYARKOV, DZUNG TRUNG LE, BA DINH VO, HOA THI PHAN, TANG VAN DUONG, ROBERT W. MURPHY, and SANG NGOC NGUYEN. "A new species of Leptolalax (Anura: Megophryidae) from Son Tra Peninsula, central Vietnam." Zootaxa 4388, no. 1 (February 28, 2018): 1. http://dx.doi.org/10.11646/zootaxa.4388.1.1.

Full text

Abstract:

Morphological, acoustic and molecular analyses result in the description of Leptolalax rowleyae sp. nov., a new species of frog in the Megophryidae, belonging to the L. applebyi Rowley & Cao species group from central Vietnam. It differs from its congeners by a combination of the following morphological attributes: (1) adult SVL 23.4–25.4 mm in males and 27–27.8 mm in females; (2) presence of distinct dark/brown dorsolateral markings, including black spots on flanks; (3) pinkish milk-white to light brown chest and belly with numerous white speckles; (4) tympanum distinct; (5) absence of webbing or lateral dermal fringes on fingers and toes; (6) pectoral glands comparatively small (3.3–4.7% of SVL); (7) ventrolateral glands indistinct; and (8) iris bicolored with copper tint in upper half fading to golden in lower third of iris. The male advertisement call of the new species consists of 4–6 notes, lacking a distinct introductory note, with an average dominant frequency of 3.2–3.5 kHz. The description of the tadpole constitutes the first description of larval morphology for a member of the L. appleybi species group. Genetically, an uncorrected sequence divergence of 7.4% for 16S rRNA separates the new species from its two closest relatives, L. ardens and L. melicus in the L. applebyi species group.

APA, Harvard, Vancouver, ISO, and other styles

48

Da Fonseca Filho, Lucilo Bioni, Priscilla Virgínio De Albuquerque, Silvia Fernanda Alcântara, Júlio Cézar dos Santos Nascimento, Maria Eduarda Luiz Coelho De Miranda, Gilcifran Prestes De Andrade, Lourival Barro de Sousa Brito Pereira, Fernanda Barreto Afonso Menezes, Emanuela Polimeni De Mesquita, and Marleyne José Afonso Accioly Lins Amorim. "Macroscopic Description of Small and Large Intestine of the Sloth Bradypus variegatus." Acta Scientiae Veterinariae 46, no. 1 (December 12, 2018): 7. http://dx.doi.org/10.22456/1679-9216.89376.

Full text

Abstract:

Background: Sloths of the species Bradypus variegatus are mammals with peculiar habits, which feed mostly young leaves of ‘embaúba’ and occur broadly in Central and South America. This specie has the greatest occurrence in Brazilian Northeast, making it a biological model for several researches in the fields as anatomy, physiology, genetics, pathology, histology and ecology, which provide data to literature in order to benefit maintenance and preservation of these animals. This study aimed to describe unpublished data about small and large intestine anatomy of the sloth Bradypus variegatus, in order to collaborate for knowledge of its digestive processes.Materials, Methods & Results: In order to perform this present research, 10 corpses of specie Bradypus variegatus belonged to the acquis of Anatomy Division, Department of Animal Morphology and Physiology (DMFA); Federal Rural University of Pernambuco (UFRPE), with 5 males and 5 females, the study was authorized by Animal Use and Experimentation Ethic Committee license (CEUA-UFRPE), nº 034/2015. All 10 animals used had natural death, were obtained through a donation of CETAS Tangará (Centro de Triagem de Animais Silvestres - Wildlife Screening Center), and located in the city of Recife. Animals were dissected at abdominal and pelvic portion, from a median sagittal incision, followed by lateral folding of skin, muscle and withdrawal of pubis portion for exposition and description of intestines, with analysis of syntopy and measurement of these organs. A relation was observed among external holes of urinary, reproductive and digestive systems. A relation was still observed among intestines and stomach, liver, kidneys, bladder and abdominal cavity wall. Some animals had absence of sigmoid colon, ventral and dorsal descendent colon. Regarding measurement, small intestine ranged from 147.09 to 163.59 cm for males and 117.44 to 151.28 cm for females, while large intestine varied between 39.68 and 43.35 cm for males, and 33.19 and 44.47 cm for females. Urinary and reproductive systems had a same external hole at perineal portion for both gender. Whereas digestive system ended at anus as occur commonly among mammals.Discussion: Among specimens described, most had the same anatomic profile regarding the intestinal portions and syntopy performed over other abdominal cavity organs. A difference was observed on liver size, increment of 20% for females and males sampled, excluding animals that had absence of structure that were minority, once 40% of females had no ventral descending colon, 20% of males and females had no sigmoid colon, and 20% of males had no dorsal descending colon. However, some animals that had absence demonstrated increase of other adjacent structures, for example, male that had no dorsal descending colon developed the largest sigmoid colon observed among animals measured for portions of duodenum, ventral descending colon, ascending colon and dorsal descending colon. Regarding the measurement of small and large intestine, Bradypus variegatus had differences compared to other herbivores, what suggests that this fact is associated to a restricted diet, in which that animal is submitted. Because of literature shortage about digestive system of specie Bradypus variegatus and other species of wild animals in general, it still difficult to infer or plot more accurate affirmations about this subject.

APA, Harvard, Vancouver, ISO, and other styles

49

Truszkowska, Wanda. "Fungi of the genera Pseudovalsa, Melanconis et Cryptospora in Poland." Acta Mycologica 12, no. 1 (November 21, 2014): 91–112. http://dx.doi.org/10.5586/am.1976.003.

Full text

Abstract:

The author presents results of investigations on some specie~ of the genera Pseudovalsa, Melanconis and Cryptospora collected since 1955 in Poland. Samples found in herbaries in Poland were examined. Descriptions of perfect and accompanying imperfect forms were made.

APA, Harvard, Vancouver, ISO, and other styles

50

GILBERT, CARTER R., RICHARD L. MAYDEN, and STEVEN L. POWERS. "Morphological and genetic evolution in eastern populations of the Macrhybopsis aestivalis complex (Cypriniformes: Cyprinidae), with the descriptions of four new species." Zootaxa 4247, no. 5 (March 30, 2017): 501. http://dx.doi.org/10.11646/zootaxa.4247.5.1.

Full text

Abstract:

For many years the North American cyprinid fish Macrhybopsis aestivalis (common name: Speckled Chub) was regarded as a single widespread and morphologically variable species, occurring in rivers throughout much of the Mississippi Valley and geographically adjacent eastern Gulf slope drainages, west to the Rio Grande basin in Texas, New Mexico, and Mexico. Eisenhour (1997) completed a morphological study of western populations of the Speckled Chub, the results of which appeared thereafter in published form (Eisenhour 1999, 2004). He demonstrated the existence of five valid species west of the Mississippi River (aestivalis, marconis, australis, tetranema, hyostoma), of which the name aestivalis was shown to be restricted to the population occurring in the Rio Grande and the geographically adjacent Rio San Fernando system, in northeastern Mexico. Eisenhour (2004) considered populations throughout the middle Mississippi Valley and its major tributaries to be a single morphologically variable species (hyostoma), and he also indicated that populations of Macrhybopsis from eastern Gulf slope drainages may represent a complex of species. Genetic confirmation of Eisenhour’s conclusions regarding western species appeared in the publication by Underwood et al. (2003), who also showed that western populations of M. hyostoma, as presently recognized, are genetically much more complex than previously considered. Meanwhile, the present authors were involved in a companion study of eastern populations of Macrhybopsis, for which a genetic summary of the eastern Gulf coast species was published by Mayden & Powers (2004). Based on their findings, four species were recognized from southeastern drainages (identified as species A–D), although no formal taxonomic descriptions were included. Their genetic data, in combination with meristic, morphometric and other morphological data presented herein, form the basis for a revised classification of eastern Macrhybopsis populations, including formal descriptions of the four new species from eastern Gulf coast drainages.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Speckle description'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles