Gene expression profiles of fathead minnows exposed to surface waters above and below a sewage treatment plant in Minnesota     

Garcia-Reyero N  Adelman I  Liu L  Denslow N 《Marine environmental research》2008,66(1):134-136

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Formation of seep bubble plumes in the Coal Oil Point seep field   总被引：2，自引：2，他引：0  

Ira Leifer  Daniel Culling 《Geo-Marine Letters》2010,30(3-4):339-353

The fate of marine seep gases (transport to the atmosphere or dissolution, and either bacterial oxidation or diffusion to the atmosphere) is intimately connected with bubble and bubble-plume processes, which are strongly size-dependent. Based on measurements with a video bubble measurement system in the Coal Oil Point seep field in the Santa Barbara Channel, California, which recorded the bubble-emission size distribution (Φ) for a range of seep vents, three distinct plume types were identified, termed minor, major, and mixed. Minor plumes generally emitted bubbles with a lower emission flux, Q, and had narrow, peaked Φ that were well described by a Gaussian function. Major plumes showed broad Φ spanning very small to very large bubbles, and were well described by a power law function. Mixed plumes showed characteristics of both major and minor plume classes, i.e., they were described by a combination of Gaussian and power law functions, albeit poorly. To understand the underlying formation mechanism, laboratory bubble plumes were created from fixed capillary tubes, and by percolating air through sediment beds of four different grain sizes for a range of Q. Capillary tubes produced a Φ that was Gaussian for low Q. The peak radius of the Gaussian function describing Φ increased with capillary diameter. At high Q, they produced a broad distribution, which was primarily described by a power law. Sediment-bed bubble plumes were mixed plumes for low Q, and major plumes for high Q. For low-Q sediment-bed Φ, the peak radius decreased with increasing grain size. For high Q, sediment-bed Φ exhibited a decreased sensitivity to grain size, and Φ tended toward a power law, similar to that for major seep plumes.  相似文献   

A nonlinear oscillator analog of rigid body dynamics     

John L. Junkins  Ira D. Jacobson  Jeffrey N. Blanton 《Celestial Mechanics and Dynamical Astronomy》1973,7(4):398-407

A rigorously valid nonlinear oscillator analog of the torque-free rotational dynamics of a general rigid body is presented. The analog consists of threeuncoupled nonlinear oscillators, the motion of each being governed by a second order nonlinear ordinary differential equation of the Duffing type. The nonlinear oscillator analog and three associated phase planes, as established herein, provide a new basis for analysis and visualization of rigid body dynamics. The phase planes are particularly useful in providing complete visibility of the motion's limiting cases and stability properties.  相似文献   

Collisional processes in stellar systems     

Ira H. Gilbert 《Astrophysics and Space Science》1971,14(1):3-10

The theory of collisional relaxation in stellar systems is discussed in terms of an expansion in powers of 1/N, the inverse of the total number of stars. The results are expressed in terms of the concept of gravitational polarization.  相似文献   

Non-equilibrium effects in steady relativistic e⁺e^−γ winds     

Ole M. Grimsrud  & Ira Wasserman 《Monthly notices of the Royal Astronomical Society》1998,300(4):1158-1180

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Precession of the isolated neutron star PSR B1828−11     

Taner Akgün  Bennett Link  Ira Wasserman 《Monthly notices of the Royal Astronomical Society》2006,365(2):653-672

Stairs, Lyne & Shemar have found that the arrival-time residuals from PSR B1828−11 vary periodically with a period ≈500 d. This behaviour can be accounted for by precession of the radio pulsar, an interpretation that is reinforced by the detection of variations in its pulse profile on the same time-scale. Here, we model the period residuals from PSR B1828−11 in terms of precession of a triaxial rigid body. We include two contributions to the residuals: (i) the geometric effect, which arises because the times at which the pulsar emission beam points towards the observer varies with precession phase; and (ii) the spin-down contribution, which arises from any dependence of the spin-down torque acting on the pulsar on the angle between its spin     and magnetic     axes. We use the data to probe numerous properties of the pulsar, most notably its shape, and the dependence of its spin-down torque on     , for which we assume the sum of a spin-aligned component (with a weight  1 − a   ) and a dipolar component perpendicular to the magnetic beam axis (weight a ), rather than the vacuum dipole torque  ( a = 1)  . We find that a variety of shapes are consistent with the residuals, with a slight statistical preference for a prolate star. Moreover, a range of torque possibilities fit the data equally well, with no strong preference for the vacuum model. In the case of a prolate star, we find evidence for an angle-dependent spin-down torque. Our results show that the combination of geometrical and spin-down effects associated with precession can account for the principal features of the timing behaviour of PSR B1828−11, without fine tuning of the parameters.  相似文献   

Annual review of ocean affairs: Law and policy, main documents 1988 : Volume III compiled and edited by the United Nations Office for Ocean affairs and the Law of the Sea UNIFO Publishers, Sarasota, FL 1990, xi + 473 pp, $92.50 casebound     

Martin Ira Glassner 《Marine Policy》1991,15(6)

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Can the Waves Generated by Fast Ferries be a Physical Model of Tsunami?     

Ira Didenkulova  Efim Pelinovsky  Tarmo Soomere 《Pure and Applied Geophysics》2011,168(11):2071-2082

The potential of long ship-induced waves to serve as a physical model for tsunami waves (called simply tsunami below) is examined. Such waves (wavelengths more than 200 m at depths down to 10–20 m) are induced by high-speed ferries sailing at near-critical speeds in semisheltered, relatively shallow areas. It is shown based on experience from Tallinn Bay, Baltic Sea, that for many aspects these waves can model nearshore dynamics and runup of tsunami caused by landslides, including processes of wave refraction, diffraction, and sea-bottom interaction in bays and harbors. Many governing nondimensional parameters (such as the nonlinearity, dispersion, Reynolds and Ursell numbers, surf similarity parameter, breaking parameter, etc.) of the largest ship waves and landslide tsunamis have the same order of magnitude. It is especially important that use of ship waves for wave propagation and runup studies allows their spatial structure to be accounted for adequately. Near-critical ship waves can therefore be used as a natural substitute for tsunami, for study under controlled and safe conditions.  相似文献   

Runup Characteristics of Symmetrical Solitary Tsunami Waves of “Unknown” Shapes     

Ira Didenkulova  Efim Pelinovsky  Tarmo Soomere 《Pure and Applied Geophysics》2008,165(11-12):2249-2264

The problem of tsunami wave runup on a beach is discussed in the framework of the rigorous solutions of the nonlinear shallow-water theory. We present an analysis of the runup characteristics for various shapes of the incoming symmetrical solitary tsunami waves. It will be demonstrated that the extreme (maximal) wave characteristics on a beach (runup and draw-down heights, runup and draw-down velocities and breaking parameter) are weakly dependent on the shape of incident wave if the definition of the “significant” wavelength determined on the 2/3 level of the maximum height is used. The universal analytical expressions for the extreme wave characteristics are derived for the runup of the solitary pulses. They can be directly applicable for tsunami warning because in many cases the shape of the incident tsunami wave is unknown.  相似文献   

Constraints on the mass and abundance of black holes in the Galactic halo: the high-mass limit     

Chigurupati Murali  †  Phil Arras  Ira Wasserman 《Monthly notices of the Royal Astronomical Society》2000,313(1):87-98

We establish constraints on the mass and abundance of black holes in the Galactic halo by determining their impact on globular clusters, which are conventionally considered to be little evolved. Using detailed Monte Carlo simulations and simple evolutionary models, we argue that black holes with masses M _bh≳(1–3)×10⁶ M_⊙ can comprise no more than a fraction f _bh≈0.17 of the total halo density at Galactocentric radius R ≈8 kpc. This bound arises from requiring stability of the cluster mass function. A more restrictive bound may be derived if we demand that the probability of destruction of any given, low-mass M _c≈(2.5–7.5)×10⁴ M_⊙] globular cluster not exceed 50 per cent; this bound is f _bh≲0.025–0.05 at R ≈8 kpc. This constraint improves those based on disc heating and dynamical friction arguments as well as current lensing results. At smaller radius the constraint on f _bh strengthens, while at larger radius an increased fraction of black holes is allowed.  相似文献