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Collision

Distribution by Scientific Domains
Earth and Environmental Science24%
Chemistry23%
Physics and Astronomy13%
Medical Sciences12%
Engineering8%
Life Sciences6%
Information Science and Computing3%
Humanities and Social Sciences3%
6 Other Domains8%
Distribution within Earth and Environmental Science
Geology & Geophysics33%
Geochemistry & Mineralogy20%
8 Other Subdomains47%

Kinds of Collision

  • continent collision
  • continental collision
    		•
  • inelastic collision
  • motor vehicle collision
    		•
  • vehicle collision

    • Terms modified by Collision

  • collision avoidance
  • collision cell
  • collision detection
    		•
  • collision energy
  • collision frequency
  • collision gas
    		•
  • collision orogen
  • collision probability
  • collision process
    		•
  • collision rate
  • collision theory

    • Selected Abstracts

    PSYCHOTROPIC MEDICATIONS AND MOTOR VEHICLE COLLISIONS IN PATIENTS WITH DEMENTIA

    JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 10 2008
    Mark J. Rapoport MD
    No abstract is available for this article. [source]

    COLLISIONS BETWEEN SHIPS AND WHALES

    MARINE MAMMAL SCIENCE, Issue 1 2001
    David W. Laist
    Abstract Although collisions with motorized ships are a recognized source of whale mortality, little has been done to compile information on the frequency of their occurrence or contributing factors. We searched historical records and computerized stranding databases for evidence of ship strikes involving great whales (i. e., baleen whales and the sperm whale). Historical records suggest that ship strikes fatal to whales first occurred late in the 1800s as ships began to reach speeds of 13-15 kn, remained infrequent until about 1950, and then increased during the 1950s-1970s as the number and speed of ships increased. Of 11 species known to be hit by ships, fin whales (Balaenoptera physalus) are struck most frequently; right whales (Eubalaena glacialis and E. australis), humpback whales (Megaptera novaeangliae), sperm whales (Physeter catodon), and gray whales (Escbricbtius robustus) are hit commonly. In some areas, one-third of all fin whale and right whale strandings appear to involve ship strikes. To assess contributing factors, we compiled descriptions of 58 collisions. They indicate that all sizes and types of vessels can hit whales; most lethal or severe injuries are caused by ships 80 m or longer; whales usually are not seen beforehand or are seen too late to be avoided; and most lethal or severe injuries involve ships travelling 14 kn or faster. Ship strikes can significantly affect small populations of whales, such as northern right whales in the western North Atlantic. In areas where special caution is needed to avoid such events, measures to reduce the vessel speed below 14 kn may be beneficial. [source]

    Demography of the California Condor: Implications for Reestablishment

    CONSERVATION BIOLOGY, Issue 4 2000
    Vicky J. Meretsky
    The most prominent mortality factor was lead poisoning resulting from ingestion of bullet fragments in carcasses. Successful captive breeding has allowed many birds to be released to the wild since 1992, based originally on an assumption that exposure to lead could be prevented by food subsidy. The mortality of released birds, however, has generally exceeded levels needed for population stability calculated from simple population models. Collision with overhead wires was the most frequent cause of death in releases before 1994. Lead poisoning again surfaced as a problem starting in 1997 as older birds began feeding on carcasses outside the subsidy program. Although poisonings have been treated successfully by chelation therapy in recaptured birds, food subsidy is proving an ineffective solution to lead exposure. The best long-term solution appears to be either the creation of large reserves where hunting is prohibited or the restriction of hunting to nontoxic ammunition in release areas. Until sources of lead contamination are effectively countered, releases cannot be expected to result in viable populations. In addition, problems involving human-oriented behavior have resulted in the permanent removal of many released birds from the wild. The most promising reduction in human-oriented behavior has been achieved in one release of aversively conditioned, parent-reared birds. Rigorous evaluation of the factors reducing attraction to humans and human structures has been hampered by confounding of techniques in releases. Behavioral problems could be more quickly overcome by adoption of a comprehensive experimental approach. Resumen: Las poblaciones silvestres remanentes del cóndor de California (Gymnogyps californianus) de los anős 80 exhibieron una disminución poblacional rápida debido a altas tasas de mortalidad de individuos adultos e inmaduros. El factor de mortalidad más prominente fue el envenenamiento por plomo ocasionado por la ingestión de fragmentos de municiones en cadáveres. La reproducción exitosa en cautiverio ha permitido muchas liberaciones en ambientes silvestres desde 1992, bajo el argumento de que la exposición al plomo puede ser prevenida mediante el subsidio de alimento. Sin embargo, la mortalidad de aves liberadas ha excedido generalmente los niveles necesarios para alcanzar una estabilidad poblacional calculada a partir de modelos poblacionales simples. Las colisiones con alambres en lo alto fueron la causa más frecuente de las muertes en liberaciones anteriores a 1994. A partir de 1997, el envenenamiento con plomo surgió una vez más como un problema, puesto que las aves de edad avanzada comenzaron a alimentarse de cadáveres fuera del programa de subsidio. A pesar de que el envenenamiento ha sido tratado exitosamente mediante terapia de quelación de las aves recapturadas, el subsidio de alimento ha probado ser una solución ineficaz contra la exposición al plomo. Las mejores soluciones de largo plazo aparentan ser la creación de reservas grandes donde la caza sea prohibida o se restrinja la caza a municiones no tóxicas en las áreas de liberación. Solo una vez que la contaminación por plomo sea contrarrestada efectivamente, no se podrá esperar que las liberaciones resulten en poblaciones viables. Además, los problemas de conductas orientadas hacia humanos ha resultado en la remoción permanente de muchas aves liberadas de zonas silvestres. La reducción más prometedora de conductas orientadas hacia humanos ha sido obtenida en una liberación de aves criadas por sus padres y condicionadas adversamente. La evaluación rigurosa de los factores que reducen la atracción hacia humanos y estructuras de humanos ha sido obstaculizada por la confusión de técnicas en las liberaciones. Los problemas de conducta podrían ser superados más rápidamente mediante la adopción de una estrategia experimental comprensiva. [source]

    Investigation of the Start Transient in a Hall Thruster

    CONTRIBUTIONS TO PLASMA PHYSICS, Issue 9-10 2008
    H. Liu
    Abstract A two dimensional axisymmetric fully kinetic Particle-in-Cell/Monte Carlo Collision (PIC-MCC) model is used to describe the ignition process in a Hall thruster. A current peak and latter the periodic oscillation of current and electric potential are found. The corresponding evolutions of plasma density, electric potential and atom density during the ignition process are introduced in the paper. In addition, influences of mass flow rate and discharge potential on current peak are modeled and analyzed. The simulated results are consistent with former experimental results. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Start-Up Transient in a Hall Thruster

    CONTRIBUTIONS TO PLASMA PHYSICS, Issue 10 2006
    F. Taccogna
    Abstract For the first time a two dimensional axisymmetric fully kinetic Particle-in-Cell/Monte Carlo Collision (PICMCC) model is used to describe the start-up transient of the acceleration channel in a Hall thruster. The Poisson equation and a secondary electron emission model are invoked for the description of the plasma dynamic phase. Numerical results have been used to see the formation and evolution of the discharge inside the channel. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Trace Element Determination by ICP-AES and ICP-MS: Developments and Applications Reported During 2004 and 2005

    GEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 3 2006
    Kathryn L. Linge
    This review describes significant developments in trace element determination using inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS) that were reported in 2004 and 2005. It focuses on the application of ICP techniques to geological and environmental samples; fundamental studies in ICP-MS and ICP-AES instrumentation are not included. The literature reviewed indicated that the majority of new publications concerned advances in ICP-MS analysis rather than ICP-AES. However, ICP-AES developments are still being published, particularly in the areas of sample preconcentration and sample introduction. The trend in increasing publication of developments in hyphenated speciation techniques looks set to persist as knowledge of elemental speciation becomes critical for many environmental studies. Collision or reactions cells were the most reported technique for spectral interference removal in ICP-MS, probably reflecting the growing adoption of cell instruments in laboratories during the last few years. [source]

    Norm Collision: Explaining the Effects of International Human Rights Pressure on State Behavior

    INTERNATIONAL STUDIES REVIEW, Issue 2 2004
    Sonia Cardenas
    Scholars have offered several types of explanations regarding how international human rights pressure can shape state behavior. Some of these explanations are rationalist-materialist in orientation, emphasizing realist notions of power or neoinstitutionalist concerns with self-interest. Others have drawn on ideational-constructivist accounts to emphasize the role of norms, identity, and social actors. Additionally, scholars have paid attention to how international and domestic factors, sometimes in interaction, mediate human rights change. This essay surveys this literature, noting a trend toward theoretical synthesis; it also draws on insights from quantitative research and comparative politics to account for persistence in human rights violations and, more specifically, the timing of policy successes and failures. [source]

    Laplacian Electrograms and the Interpretation of Complex Ventricular Activation Patterns During Ventricular Fibrillation

    JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2000
    PH.D., RUBEN CORONEL M.D.
    Laplacian Electrograms and Ventricular Fihrillation. Introduction. During ventricular fibrillation (VF) interpretation of a local electrogram and determination of the local activation moment are hampered by remote activity or intervening repolarization waves. Successful defibrillation depends on critical timing of the shock relative to local activation. We tested the applicabillity of Laplacian electrograms for detection of the moment of local activation during VF. Methods and Results. From isolated perfased porcine infact heart, 247 local unipolar electrograms were recorded simultaneously (13 × 19 matrix, interelectrode distance 0.3 mm) from the left ventricular wall during sinus rhythm, following pacing or during VF, Activation maps were constructed based on local unipolar electrograms, and Laplacian electrograms were calculated from local electrograms ane its eight neighbors. The Laplacian electrogram displayed a sharp R/S complex with local activation iodicted by the moment of zero crossing without interference from remote activity or repolarization waves. Its amplitude increased with decreasing interelectrode distance, Following epicardial stimulation, Laplacian amplitude was significantly larger than during complexes with different morphology. Collision of wavefronts was associated with entirely positive Laplacian waveforms; "focal" appearancce of acitivity was associated with an entirely negative waveform. Activation block in the activation maps was correlated with the appearance of substanined episodes of negativity or positivity in the Laplacian electrogram (depending on the location of the recording site relative to the line of block). Conclusion. Laplacian electrograms allow detection of the moment of local activation without interference from remote activity or repolarization, especially during complex arrhythmias. The technique applied toe automatic sensing devices, such its the internal defibrillator, may optimize defibrtilation success. (J Cardiovasc Electrophysiol, Vol. 11, pp. 1119-1128, October 2000) [source]

    Characterization of the Triacylglycerol Crystal Formation in Adipose Tissue During a Vehicle Collision

    JOURNAL OF FORENSIC SCIENCES, Issue 4 2007
    Barbara H. Stuart Ph.D.
    Abstract:, The unusual appearance of crystalline fat structures was observed during the postmortem examination of a motor vehicle accident victim. The crystal structures were characterized using Fourier transform infrared spectroscopy and x-ray diffractometry. The structures were found to be made of triacylglycerols, a dominant lipid structure found in human adipose tissue, capable of forming various polymorphic structures. The morphology of the crystalline material was found using both techniques to be predominantly the ,, form of triacylglycerols. The accelerated growth of such triacylglycerol morphology has been observed as a result of shear stresses in other studies involving edible fats. As a result of the findings of this study, it is proposed that increased shear forces may be responsible for the formation of the unusual fat structure found in the victim. An understanding of the effect of forces on the structure of body fat in high-impact collisions can potentially assist in verifying a high-velocity impact. [source]

    Global Corporations and Sovereign Nations: Collision or Cooperation? by David J. Saari

    JOURNAL OF POLICY ANALYSIS AND MANAGEMENT, Issue 3 2002
    Daniel J.B. Mitchell
    [source]

    The Story Catches You and You Fall Down: Tragedy, Ethnography, and "Cultural Competence"

    MEDICAL ANTHROPOLOGY QUARTERLY, Issue 2 2003
    Janelle S. Taylor
    Anne Fadiman 's The Spirit Catches You and You Fall Down: A Hmong Child, Her American Doctors, and the Collision of Two Cultures (Noonday Press, 1997) is widely used in "cultural competence" efforts within U.S. medical school curricula. This article addresses the relationship between theory, narrative form, and teaching through a close critical reading of that book that is informed by theories of tragedy and ethnographies of medicine. I argue that The Spirit Catches You is so influential as ethnography because it is so moving as a story; it is so moving as a story because it works so well as tragedy; and it works so well as tragedy precisely because of the static, reified, essentialist understanding of "culture" from which it proceeds. If professional anthropologists wish our own best work to speak to "apparitions of culture" within medicine and other "cultures of no culture," I suggest that we must find compelling new narrative forms in which to convey more complex understandings of "culture." [medical education, cultural competence, tragedy, ethnography, theories of culture] [source]

    Bush's New China Policy: Air Collision, Arms Sales and China-U.S. Relations

    PACIFIC FOCUS, Issue 2 2001
    Sheng Lijun
    First page of article [source]

    Determination of phenolic compounds in rose hip (Rosa canina) using liquid chromatography coupled to electrospray ionisation tandem mass spectrometry and diode-array detection

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2002
    Erlend Hvattum
    Liquid chromatography coupled with negative and positive electrospray ionisation (ESI) tandem mass spectrometry (MS/MS) and diode-array detection (DAD) was used for determination of phenols in rose hip (Rosa canina) extract. ESI mass spectra of the chromatographically separated phenols gave the molecular weight of the compounds through prominent [M,,,H], ions for most of the compounds and M+ ions for the anthocyanins. Collision induced dissociation (CID) of the [M,,,H], (or M+) precursor ions yielded product ions which determined the molecular weight of the aglycones. In-source fragmentation followed by CID of the resulting deprotonated aglycone ([A,,,H],) provided product ions for the identification of the unconjugated phenols. The identification was based on comparison with product ion spectra of commercial standards. UV-diode-array spectra were used for identity confirmation. This combined approach allowed the identification in rose hip extract of an anthocyanin, i.e. cyanidin-3- O -glucoside, several glycosides of quercetin and glycosides of taxifolin and eriodictyol. Phloridzin was identified, and several conjugates of methyl gallate were also found, one of which was tentatively identified as methyl gallate-rutinoside. Catechin and quercetin were found as the aglycones in the extract. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    The History of Latin America: Collision of Cultures by Marshall C. Eakin

    THE LATIN AMERICANIST, Issue 2 2008
    Eric Minzenberg
    No abstract is available for this article. [source]

    Collision of invasive serous adenocarcinoma and mature cystic teratoma in the ovary,

    APMIS, Issue 6 2007
    Letter to the editor
    No abstract is available for this article. [source]

    Direct Numerical Simulation of Dense Gas-Solid Two-Phase Flows

    ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3-4 2000
    Y. Zhulin
    Based on Newton's law and the classical physical laws, Eulerian and Lagrangian methods are respectively used to deal with gas-field and discrete particles. The three-dimensional viscid air-field and three-dimensional discrete particle field are solved in each time step ,t. Collision and friction between individual particles are taken into account when establishing the mathematical models, including individual particle diameter, density, stiffness and friction coefficient. Particles mixing in ball mills, particles dropping from hoppers, and particles fluidizing in fluidized beds are used as examples of the simulations. Selected simulated results are compared to experimental results. [source]

    On-line hybrid test combining with general-purpose finite element software

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 12 2006
    Tao Wang
    Abstract A new on-line hybrid test system incorporated with the substructuring technique is developed. In this system, a general-purpose finite element software is employed to obtain the restoring forces of the numerical substructure accurately. The restart option is repeatedly used to accommodate the software with alternating loading and analysis characteristic of the on-line test but without touching the source code. An eight-storey base-isolated structure is tested to evaluate the feasibility and effectiveness of the proposed test system. The overall structure is divided into two substructures, i.e. a superstructure to be analysed by the software and a base-isolation layer to be tested physically. Collisions between the base-isolation layer and the surrounding walls are considered in the test. The responses of the overall structure are reasonable, and smooth operation is achieved without any malfunction. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Ground Water Recharge and Chemical Contaminants: Challenges in Communicating the Connections and Collisions of Two Disparate Worlds

    GROUND WATER MONITORING & REMEDIATION, Issue 2 2004
    Christian G. Daughton
    Our knowledge base regarding the presence and significance of chemicals foreign to the subsurface environment is large and growing , the papers in this volume serving as testament. However, complex questions with few answers surround the unknowns regarding the potential for environmental or human health effects from trace levels of xenobiotics in ground water, especially ground water augmented with treated waste water. Public acceptance for direct or indirect ground water recharge using treated municipal waste water (especially sewage) spans the spectrum from unquestioned embrace to outright rejection. In this paper, I detour around the issues most commonly discussed regarding ground water recharge and instead focus on some of the less-recognized issues,those that emanate from the mysteries created at the many literal and virtual interfaces involved with the subsurface world. My major objective is to catalyze discussion that advances our understanding of the barriers to public acceptance of waste water reuse with its ultimate culmination in direct reuse for drinking. I pose what could be a key question as to whether much of the public's frustration or ambivalence in its decision-making process for accepting, or rejecting, water reuse (for various purposes including personal use) emanates from fundamental inaccuracies, misrepresentation, or oversimplification of what water is and how it functions in the environment,just exactly what the water cycle is. These questions suggest it might behoove us to revisit some very elementary aspects of our science and how we are conveying them to the public. [source]

    Molecular dynamics study for dissociation phenomena of a gas molecule on a metal surface

    HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 8 2008
    Takashi Tokumasu
    Abstract The dissociation phenomena of a gas molecule on a metal surface were analyzed by the molecular dynamics method. A platinum (111) surface and hydrogen were chosen as the metal surface and the gas molecule, respectively. The embedded atom method was used as the interaction between atoms in order to express the dependence of electron density. The parameters were determined so that the results such as the electron density, adsorption energy of an H atom on a Pt(111) surface, and the interaction between H atoms of an H2 molecule obtained by the EAM method were consistent with those obtained by the density functional theory or empirical function. Collisions between a hydrogen molecule and the platinum surface were simulated by the molecular dynamics method, and the dissociation probability was obtained. Using these results, the effect of the motion of the surface atoms or the hydrogen molecule on the dissociation probability was analyzed. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20222 [source]

    Molecular dynamics in the formation process of single-walled carbon nanotubes

    HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 8 2003
    Yasushi Shibuta
    Abstract The mechanism of the nucleation and formation of single-walled carbon nanotubes (SWNTs) was investigated using molecular dynamics simulations. When the initial state was chosen so that carbon and nickel atoms were randomly distributed in a simulation domain, the formation of a random cage structure made up of carbon atoms, which had a few nickel atoms inside it, was observed by 6 ns. The nickel atoms, which move inside or on the surface of the cage, were seen to be preventing the complete closure of the cage and its anneal into the fullerene structure. Further, in order to observe a longer time-scale growth process, the simulation cell was artificially shrunk by the progress of simulation so that collisions between precursor clusters were promoted to comply with the limitation in the calculation time. Collisions of the imperfect random-cage clusters led to an elongated tubular cage structure, which could be regarded as an initiation of SWNTs. The simulation results were compared with FT-ICR mass spectra of the positive clusters generated by a laser-vaporization supersonic-expansion cluster beam source. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(8): 690,699, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10123 [source]

    Simulations of Xe@C60 collisions with graphitic films

    INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 15 2008
    Victor V. Albert
    Abstract Collisions between Xe@C60 and sheets of graphite of various dimensions were simulated. A Tersoff many-body potential modeled the interactions between carbon atoms and a Lennard-Jones potential simulated the xenon-carbon interactions. The simulations were compared to experiment and with simulations which implemented other potentials. The results indicate that a relatively small graphite film can be an accurate approximation for a nearly infinite sheet of graphite. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source]

    Reactions of BBrn+ (n = 0,2) at fluorinated and hydrocarbon self-assembled monolayer surfaces: observations of chemical selectivity in ion,surface scattering

    JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 7 2001
    Nathan Wade
    Abstract Ion,surface reactions involving BBrn+ (n = 0,2) with a fluorinated self-assembled monolayer (F-SAM) surface were investigated using a multi-sector scattering mass spectrometer. Collisions of the B+ ion yield BF2+ at threshold energy with the simpler product ion BF+· appearing at higher collision energies and remaining of lower abundance than BF2+ at all energies examined. In addition, the reactively sputtered ion CF+ accompanies the formation of BF2+ at low collision energies. These results stand in contrast with previous data on the ion,surface reactions of atomic ions with the F-SAM surface in that the threshold and most abundant reaction products in those cases involved the abstraction of a single fluorine atom. Gas-phase enthalpy data are consistent with BF2+ being the thermodynamically favored product. The fact that the abundance of BF2+ is relatively low and relatively insensitive to changes in collision energy suggests that this reaction proceeds through an entropically demanding intermediate at the vacuum,surface interface, one which involves interaction of the B+ ion simultaneously with two fluorine atoms. By contrast with the reaction of B+, the odd-electron species BBr+· reacts with the F-SAM surface to yield an abundant single-fluorine abstraction product, BBrF+. Corresponding gas-phase ion,molecule experiments involving B+ and BBr+· with C6F14 also yield the products BF+· and BF2+, but only in extremely low abundances and with no preference for double fluorine abstraction. Ion,surface reactions were also investigated for BBrn+ (n = 0,2) with a hydrocarbon self-assembled monolayer (H-SAM) surface. Reaction of the B+ ion and dissociative reactions of BBr+· result in the formation of BH2+, while the thermodynamically less favorable product BH+· is not observed. Collisions of BBr2+ with the H-SAM surface yield the dissociative ion,surface reaction products, BBrH+ and BBrCH3+. Substitution of bromine atoms on the projectile by hydrogen or alkyl radicals suggests that Br atoms may be transferred to the surface in a Br-for-H or Br-for-CH3 transfer reaction in an analogous fashion to known transhalogenation reactions at the F-SAM surface. The results for the H-SAM surface stand in contrast to those for the F-SAM surface in that enhanced neutralization of the primary ions gives secondary ion signals one to two orders of magnitude smaller than those obtained when using the F-SAM surface, consistent with the relative ionization energies of the two materials. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    Mortality of Northern Bluefin Tuna Thunnus thynnus Due to Trauma Caused by Collision During Growout Culture

    JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 4 2000
    Shigeru Miyashita
    Collisions with the walls of tanks or nets caused mass mortality that occurs during growout. The period when collisions frequently occur and the types of injury caused by collision were examined in this study. Juveniles were reared in indoor tanks from 30 to 120 d after hatching, and in an open sea net cage from 42 to 150 d after hatching. Dead fish were collected and counted daily in both of the experiments. In the indoor experiment, the sampled fish were preserved in 10% formalin solution, and each of 10 specimens of about 30, 50, 70, 85, 100, 130, 160 and 225 mm in body length (BL) were examined using x-rays to detect injury of the bones. Juvenile and young adult bluefin tuna showed a reduction in numbers caused by collision with the tank or the net wall during the experiments. In the indoor tank, there were 1,200 fish on day 30 but only eight on day 120. The daily mortality increased from day 30 after hatching, when juveniles reached 50-mm BL and remained over 4%/d until day 60 when juveniles grew to 300-mm BL. The proportion of dead fish with injuries of bone, especially of the vertebral column and the parasphenoid, increased after fish reached 50-mm BL, and exceeded 60% in fish with BL 85 mm or greater. In the open sea net cage, there were 3,841 fish at the start of the experiment on day 42 and only 65 on day 150. In this experiment, the reduction was greatest from the start of the experiment until day 80, when fish grew to approximately 25 cm in total length. Significant bacterial, viral or parasitic diseases were not observed in these fish; the only findings were dislocations of the vertebral column and injuries to the upper and lower jaws. These results show that the loss of juvenile and young adult bluefin tuna was caused by collision with the tank or net wall that fatally damaged the bones of the vertebral columns and the parasphenoid. [source]

    A smoothed particle hydrodynamics simulation of the collapse of the interstellar medium

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2001
    Y. Golanski
    A smoothed particle hydrodynamic (SPH) code is used to model a collapsing region of the interstellar medium (ISM). A region of the ISM is seeded with coolant material ejected from a supernova. The resulting pressure imbalance between the cooling region and the surrounding ISM induces collapse. The collapse first forms dense low-temperature regions (protoclouds) each containing several tens of solar masses of material and in quasi-equilibrium with the surrounding ISM. Turbulence is generated within the collapsing regions as they form. Collisions between protoclouds leads to regions of further increased mass and density, the final outcome being a dense cold cloud with mean density 10,18 kg m,3, mean temperature about 20 K and total mass a few hundred solar masses. The final cloud is sufficiently turbulent for star formation to occur within it. A new form of boundary condition was used in the SPH simulation to solve the problem inherent in modelling a continuum. [source]

    Multiple Soft Ionization of Gas-Phase Proteins and Swift Backbone Dissociation in Collisions with ,99,eV Electrons,

    ANGEWANDTE CHEMIE, Issue 8 2010
    Roman
    Unerwartet: Elektronen mit einer Energie über 20,eV können Polypeptide mehrmals ionisieren (siehe Bild), ohne dabei die Primär- oder sogar Elemente der Tertiärstruktur zu zerstören. Durch gleichzeitige elektronische Anregung lassen sich Rückgratbindungen rasch spalten, wobei schwache Molekül-Molekül-Bindungen intakt bleiben. Dieses ,sanfte Fragmentieren" sollte eine genaue Charakterisierung der Struktur von Proteinkomplexen ermöglichen. [source]

    Multi-resolution collision handling for cloth-like simulations

    COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 3-4 2005
    Nitin Jain
    Abstract We present a novel multi-resolution algorithm for simulation of complex cloth-like deforming meshes. Our algorithm precomputes a multi-resolution hierarchy by using a combination of ,chromatic decomposition'1 and polygonal simplification of the underlying mesh. At runtime we selectively refine or coarsen the mesh based on the collision proximity of the mesh primitives with non-adjacent primitives. Our algorithm handles all kind of contacts, including self collisions among mesh primitives. The multi-resolution hierarchy is used to compute simplification of contact manifolds and to accelerate collision detection and response computations. We have implemented our algorithm on a high-end PC and applied it to complex simulations with tens of thousands of polygons. In practice, our algorithm is able to achieve interactive performance, while maintaining good visual fidelity. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Using particles for 3D texture sculpting

    COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 4 2001
    ich Bene
    Abstract Particle systems have been used in computer graphics for many different purposes, including visual simulation of fur, grass, hair, and similar fuzzy textures and shapes. The underlying theories used in these algorithms are usually quite complex and are mostly based on simulation of diffuse-limited aggregation, cellular development, reaction-diffusion models, etc. This leads to high time complexity of these algorithms. The purpose of this paper is to show that collision detection and distance keeping among moving particles can generate similar realistic textures efficiently. This approach is easy to implement, sufficiently fast allowing for interactive modeling, and inherits the major features from the previously published techniques. We first construct a scene consisting of generators of particles, attractors, and cutters. The generators generate oriented particles, and the attractors attract or repulse them. When collision with the cutter is detected, the particle performs an action according to its state and position in the 3D space. Every particle has assigned a table of possible actions that is used for solving these critical states. Trajectories of the particles are then used as a resulting shape of the texture. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    Longitudinal Dust Lattice Shock Wave in a Strongly Coupled Complex Dusty Plasma

    CONTRIBUTIONS TO PLASMA PHYSICS, Issue 8 2008
    S. Ghosh
    Abstract The effect of hydrodynamical damping that arises due to the irreversible processes within the system have been studied on 1D nonlinear longitudinal dust lattice wave (LDLW) in homogeneous strongly coupled complex (dusty) plasma. Analytical investigation shows that the nonlinear wave is governed by Korteweg-de Vries Burgers' equation. This hydrodynamical damping induced dissipative effect is responsible for the Burgers' term that causes the generation of shock wave in dusty plasma crystal. Numerical investigation on the basis of the glow-discharge plasma parameters reveal that LDLW exhibits both oscillatory and monotonic shock. The shock is compressive in nature and its strength decreases (increases) with the increase of the shielding parameter , (characteristic length L). The effects of dust-neutral collision are also discussed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Particle-in-Cell Simulation of Stationary Plasma Thruster

    CONTRIBUTIONS TO PLASMA PHYSICS, Issue 8-9 2007
    F. Taccogna
    Abstract A very good example for the application of PIC techniques for detailed studies of low-temperature plasmas is the Hall thrusters. Here, a variety of models with different complexities are needed to get better insight into the physics of these systems. Particular emphasis has been spent for the geometrical scaling, for the simulation of the plasma-wall interaction inside the acceleration channel and for ion-neutral collision into the plume emitted from the thruster. Results show the axial acceleration mechanism, the secondary electron emission instability, the azimuthal fluctuations into the channel and the ion backflow and electron trapping in the plume. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Thermally Conducting Partially Ionized Plasma in a Variable Magnetic Field

    CONTRIBUTIONS TO PLASMA PHYSICS, Issue 3 2007
    S. Shaikh
    Abstract An infinitely extending homogenous partially ionized plasma endowed with several physical mechanisms and permeated by a variable magnetic field is considered. The combined effect of these parameters, namely, Hall currents, finite conductivity, ion viscosity, collision with neutrals and thermal conductivity on the gravitational instability of the plasma is studied. It is found that the several mechanisms play different physical roles in the perturbed problem. Jeans' Criterion is analyzed in the framework of Tsallis' statistics for possible modifications due to the presence of nonextensive effects. A simple generalization of the Jeans' criterion is obtained and the standard values are obtained in the limiting case q = 1, q being the nonextensive parameter. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]