bluuebunny/crossref_metadata_2025 huggingface dataset:
Reply by author to Discussion by Gábor Korvin
Authors: Armstrong Baxter H.
Published: October 2002

Dr. Korvin makes the important observation that the square of the fluctuation amplitude f(L) introduced in equation (17) of my paper (hereafter referred to as paper I) is related to the autocorrelation function of the elastic heteorogeneity distribution of the absorbing solid. This connection permits one to explore the frequency dependence of [Formula: see text] and also provides a direct demonstration of my heuristic assumption that this quantity is independent of frequency for random heterogeneities. I believe his observations point the way toward significant advancement of the theory.
Reply by the authors to E. Szaraniec
Authors: Hubral Peter , Treitel Sven , Gutowski Paul R.
Published: October 2002

We thank Dr. Szaraniec for his interesting comments, which shed new light on the properties of the normal incidence synthetic seismogram. By the way, his equations (D‐4.1) and (D‐4.2) were also given by Nestler and Rösler [1977, equation (4)], although with an error; they write [Formula: see text] rather than [Formula: see text]. We are reminded of a saying by our colleague Prof. Dan Loewenthal of Tel Aviv University: the normal incidence discretely layered model is a rich lode from which a seemingly endless series of interesting formulas can be mined. Dr. Szaraniec has unearthed more nuggets, and we hope that his success will inspire others to continue searching. The relation between our results and the theory of continued fractions should, as Dr. Szaraniec points out, provide further insights.
Reply by the author to W. L. Anderson
Authors: Chave Alan D.
Published: October 2002

Anderson presents an interesting comparison of my direct quadrature Hankel transform algorithm with a high precision (∼ 12 significant figures) digital filter procedure that he published recently. His clarifications regarding lagged convolution are important. However, two of his major points may be misleading, and require a more careful examination.
Reply by the authors to G. H. F. Gardner
Authors: Christensen N. I. , Wang H. F.
Published: October 2002

Gardner suggests that velocity data in which confining pressure changes are not canceled by equal pore pressure changes may be due to hysteresis effects that prevent velocity from being a unique function of the differential pressure. This is supported by shear velocity measurements in dry Berea sandstone as a function of cyclic variations of differential pressure (Gardner et al., 1965). High porosity and clayey sandstones indeed can demonstrate this behavior. Cyclic pressure variations can lead to work hardening and other inelastic behavior. For our measurements, however, we believe that the effects of hysteresis were minimal because of (1) the pressure cycle followed to obtain velocity as a function of pore and confining pressures, and (2) the large elapsed time between our measurements.
Reply by the author to W. K. McClary
Authors: Treitel Sven
Published: October 2002

We are pleased to see Mr. McClary shed more light on the concept of a generalized primary. To construct the generalized primary of the nth interface as a transmitted output signal in the upper half‐space for the input wavelet −X in the lower half‐space not only indicates that this can be done, but that the construction is appealing and that it clarifies the entire concept.
Response by Richard Smith to the authors’ reply
Authors: Smith Richard
Published: October 2002

I would like to thank Marcus Flis and Gregory Newman for acknowledging that that there is more than one way of decomposing the total current into polarization and fundamental (EM) parts, although they have failed to establish that the Flis et al. (1989) decomposition is preferable to that previously suggested by Smith et al. (1988). The choice of a dc limit in the Cole‐Cole impedance model was not my main criticism; work cited as confirming the Smith et al. decomposition uses the dc limit also (Smith and West, 1988).
Reply by the authors to W. H. Mayne
Authors: Knapp Ralph W. , Steeples Don W.
Published: October 2002

Thank you for your comments. We agree with you on both points. The attenuation function of the earth is more correctly described in terms of dB per wavelength. In the process of trying to illustrate the power of and need for preemphasis filtering, we oversimplified our example. We originally wrote the paper and prepared the example for an engineering geophysics monograph where our audience would have been quite different than the typical reader of Geophycics.
Reply by the author to J. D. MacQueen and T. R. LaFehr
Authors: Lakshmanan J.
Published: October 2002

Cheops pyramid. The terrain correction is a way to correct the initial slab model which for each station is at the station elevation. In underground surveys of small horizontal but large vertical extent, I have shown (Cheops pyramid for example) that the model used (or the standard terrain corrections used) should extend greatly as compared to the 1000 m radius initally used in this case (one should bear in mind that we were looking for cavities of a few cubic meters only). Figure 8 of my paper shows that the slab + terrain correction model is quite wrong as long as the terrain correction radius is small. Note that apart from the pyramid itself, the ground is practically flat and located at the low level of the pyramid.
Reply by the author to B. N. P. Agarwal
Authors: Mohan N. L.
Published: October 2002

N. L. Mohan feels that he adequately addressed points raised earlier by Nagendra and Babu regarding the same.
Reply by the author to J. C. Macnae and Y. Lamontagne
Authors: Raiche A. P.
Published: October 2002

I am in substantial agreement with the excellent discussion raised by Macnae and Lamontagne. Certainly, if one is to base interpretation on apparent resistivity, the step response functions will be easier to interpret than the pulse response functions. However, if one were to use a Marquardt linearized least‐squares inversion scheme, the issue is not so clear cut.
Magnetic data processing for hydrocarbon exploration in the Pannonian Basin, Yugoslavia
Authors: Burazer Milenko , Grbović Milinko , Žitko Vicko
Published: October 2002

Because magnetic minerals may directly indicate the presence of oil and gas deposits, magnetic methods are applied to hydrocarbon exploration in oil‐bearing sedimentary basins. The basic problem in applying these methods is the isolation of weak magnetic anomalies sourced by low concentrations of the magnetic minerals present. These weak anomalies are often masked by much stronger magnetic anomalies caused by underlying magnetic rocks and/or by rocks in the basin sediments. Weak local anomalies can efficiently be isolated by applying selective 1‐D digital frequency filters. The method of filtering has been checked by data obtained using simple models of magnetic sources and using a model representative of the local geology in our study area in the southern Pannonian basin, Yugoslavia, The magnetic field frequency content was analyzed by applying the power spectral density estimation, using the maximum entropy method. The digital filters were designed using the window function method. The best results were obtained by the Kaiser window function for the chosen range of the band‐pass filter. In our study area, me isolated local magnetic anomalies have amplitudes of ±10 nT and trend in an east‐west direction parallel to the predominant structural grain. These anomalies correlate very well with the known oil and gas fields. As an example, filter processing of magnetic anomaly data, combined with the 3‐D seismic data gained in the filtered magnetic field, correlate well with one of the oil fields. The next phase of the project will concentrate on the anomalies occurring outside the established gas and oil fields.
Reply to A. A. Arzi by the author.
Authors: Fajklewicz Zbigniew J.
Published: October 2002

I wish to thank A. A. Arzi for taking part in the discussion on my paper. His initial statement that microgravimetry is a powerful method for the detection of many small geologic and anthropogenic bodies (Arzi, 1975) provides further confirmation of the widely accepted opinion I have written about more extensively in my reply to S. Thyssen’s discussion.
Reply by Author to Discussion by P. J. Hood
Authors: Allen S. J.
Published: October 2002

Most statistical reports, such as the Annual SEG Geophysical Activity Report, which are dependent upon voluntary submission of basic data by a large number of performing organizations, require a certain amount of averaging to arrive at values considered, or assumed, to be most representative of the actual values being measured. Most reports on geophysical activity published in Geophysics in past years have made references to the necessity for averaging and to limitations resulting mainly from incomplete responses to the questionnaires.
Reply by author to H. B. Evans
Authors: Keys W. Scott
Published: October 2002

Evans is correct about the error in the equation on p. 1140 and the caption on Figure 12. With all of the review we had, it’s hard to understand how such errors creep through.
On: “Relationship between electrical and thermal resistivities for differing grades of coal” by J. R. Kayal and D. A. Christoffel (Geophysics, v. 47, p. 127–129).
Authors: Olhoeft Gary R.
Published: October 2002

The proportionality between thermal gradient and thermal resistivity is invalid if there are thermal sources or sinks in the borehole (such as flowing water) or if the thermal gradient is high enough (above 60°C/km) to support convection (Beck, 1976). The authors allude to Beck’s work, but they neither fully support all of his assumptions nor display their data so others can test them. Further, they state that electrical resistivity increases with decreasing coal rank.
Reply by the authors
Authors: Rao D. Atchuta , Babu H. V. Ram
Published: October 2002

We thank Dr. Åm For bringing to our notice some discrepancies in our paper referred above. However, we wish to state that it is not that we have not realized the fact that the antisymmetric contact anomaly represents one of the flanks of a symmetric dike anomaly, but it was used only to distinguish the dike anomalies of finite width from the contact anomalies. It is also true that the contact anomaly is a special case of dike anomaly when one of its edges is taken to infinity. The anomaly over a dike of finite width has a different shape compared to that when one of its edges is at infinity. When one curve is symmetric, the other is antisymmetric and vice versa.
Reply by the author to E. M. Abdelrahman, A. I. Bayoumi, and Y. A. Amin
Authors: Gupta O. P.
Published: October 2002

I agree with Abdelrahman et al. The use of horizontal derivatives to estimate the depth was tried by one of my colleagues and was found to have the added advantage of resolving structural ambiguities. Formulas for derivatives can be obtained in a similar way as given in the subject paper by simply taking the derivative of the function described by relation (1). However, one has to be very careful in obtaining the derivatives, numerically, from conventional gravity survey data. Estimation of depth will be more reliable. I feel, if derivatives can be measured in field directly, which is a subject under current study.
On: “Transient electromagnetic field computations for polygonal loops on layered earths” by A. P. Raiche (GEOPHYSICS, 52, 785–793, June 1987).
Authors: Ignetik Rainer
Published: October 2002

Raiche has overlooked the related and important work of Boerner and West (1984). Their work deals with the efficient calculation of electromagnetic fields of any extended source, including polygonal loops. Raiche’s complicated three‐level integration scheme could have been avoided by using Boerner and West’s more efficient method in the frequency domain, followed by fast transformation to the time domain by convolution filtering. These techniques are well known and used frequently to compute transients in complicated 3‐D models.
Response by C. F. O’Brien to the author’s reply
Authors: O’Brien C. F.
Published: October 2002

As an admirer of Tucker’s past and present contributions to seismic interpretation, I would like to thank him for his kind remarks. On the question of data accuracy, I followed the approach he described in his reply to Stone’s comments when he said that his article “was about the philosophy and mechanics of contouring seismic data, not about the correctness of the data”. It is legitimate to honor the data as far as possible in such a context; the question of the validity of the values is an entirely separate matter, and I did not address myself to that problem.
Reply by the author to E. M. Abdelrahman
Authors: Gupta O. P.
Published: October 2002

It is good to see the analysis by Prof. Abdelrahman. He has drawn attention to minimization of two unknowns z and K in equations (3) and (4) and applied the method on synthetic data. My experience with the minimization technique with the two unknown parameters is that it gives very good results as long as we deal with synthetic data with and without error. In cases dealing with field problems, we may not get appreciable results. This sort of phenomenon has already been discussed by me in a different context (see references (1) 53rd SEG Meeting, Las Vegas p. 215; and (2) CJEG, 24, p. 179.
Reply by authors to M. O’Connell and M. Carson
Authors: Bartel D. C. , Becker A.
Published: October 2002

We welcome the comments of Messrs. O’Connell and Carson to our paper on spectral analysis interpretation of electromagnetic (EM) data. Through our comments we did not mean to imply that GEOTEM® was equivalent to INPUT® in all respects. As pointed out, only with respect to the transmitter‐receiver geometry and transmitter waveform are the GEOTEM and analog INPUT systems essentially the same.
Reply by the author to Sudhir Jain
Authors: Ziolkowski A. M.
Published: October 2002

I thank Sudhir Jain very much for his comments. My arguments against wavelet estimation are almost entirely theoretical, while his very broad experience of poststack inversion is that it works. I very much appreciate that his remarks were not made lightly. He writes, I believe, on behalf of many practicing geophysicists who share his experience.
Reply by the authors to Craig Ferris
Authors: Marson I. , Klingele E. E.
Published: October 2002

Our paper is a discussion aimed to show how the vertical gradient of gravity can be successfully used for quantitative interpretation in three dimensions (i.e., solving for the three coordinates [Formula: see text], [Formula: see text], and [Formula: see text] of the source body) with methods like analytic signal and Euler deconvolution.
Reply by the authors to M. M. Roksandic
Authors: Hardage B. A. , Levey R. A. , Pendleton Virginia , Simmons James , Edson Rick
Published: October 2002

Roksandic’s discussion is superb! Because so few papers are submitted to Geophysics that deal with seismic interpretation theory, we were concerned that our philosophy of thin‐bed interpretation might not be appreciated by the readership. We encourage Roksandic, and other interpreters who have his ability to explain concepts, to continue to submit interpretation‐based papers to Geophysics.
On: “Apparent resistivity curves in controlled‐source electromagnetic sounding directly reflecting true resistivities in a layered earth”, by U. C. Das (January‐February 1995 GEOPHYSICS, 60, 53–60).
Authors: Valla Pierre
Published: October 2002

Using a clever mix of two components of the EM field caused by a vertical magnetic dipole, U. C. Das derives what he claims to be an exact apparent resistivity for use in EM depth sounding.
Reply by the author to D. L. Warner
Authors: Zinni Ed
Published: October 2002

This reply will address Mr. Warner’s concerns pertaining to geology and geophysics which are listed and answered below. Mr. Warner’s comments pertaining to hazardous waste density, composition, chemical reactivities, hydrologic gradients, and contamination plume extent/groundwater modeling are currently being researched and are the topics of several M.Sc. theses at the University of New Orleans. Note: Hazardous waste density and chemical reactivities are very complicated issues. Dupont’s permit allows them to inject 300+ listed hazardous wastes with pH’s ranging from 2 to 12.5.
On: “A numerical evaluation of electromagnetic methods in geothermal exploration” (L. Pellerin, J. M. Johnston, and G. W. Hohmann, GEOPHYSICS, 61, 121–130)
Authors: Poddar M.
Published: October 2002

Pellerin et al. numerically modeled electromagnetic response of a geothermal body of very large size at a shallow depth and found the task difficult, specially, at high frequencies (and hence early times) due to practical limits on computing time and machine memory. To make it easy to handle, without sacrificing accuracy, I have chosen a much smaller 3‐D body than they did but otherwise kept the model essentially the same as their model. My aim is to throw more light than they did on the grounded‐source transient response from a geothermal reservoir, which they found most promising among all the electromagnetic responses considered by them.
Asymptotic error analysis of constant‐velocity viscoacoustic migration
Authors: Causse Emmanuel , Ursin Bjørn
Published: October 2002

The deterioration of prestack migration images caused by an erroneous velocity or dissipation model can be represented by a space‐variant filter. We have derived an approximate expression of this spatial filter for the case of a plane horizontal reflector between two homogeneous half‐spaces, using analytical expressions for the Green’s functions and a stationary phase approximation of the Kirchhoff integral. We have used complex, frequency‐dependent velocities to represent a general homogeneous viscoacoustic medium. Hence, the filter can describe the effects of errors in phase velocity and absorption on the image of the reflector for different situations. A pure phase velocity error deforms the reflector, affects the value of the recovered reflectivity, and creates a spurious amplitude versus offset (AVO) effect. Neglecting dissipation destroys the phase of the image, decreases the resolution, and causes an underestimation of the reflectivity. To have a true‐amplitude, good‐resolution migration with Claerbout’s crosscorrelation imaging principle, the forward extrapolation of the downgoing wavefield should be done with the complex conjugate of the velocity in the viscoacoustic medium, and the backward extrapolation of the upgoing wavefield should be done with the complex velocity. In both cases, this amplifies the wavefields to compensate for the effects of attenuation on wave propagation.
Three‐parameter AVO crossplotting in anisotropic media
Authors: Chen He , Castagna John P. , Brown Raymon L. , Ramos Antonio C. B.
Published: October 2002

Amplitude versus offset (AVO) interpretation can be facilitated by crossplotting AVO intercept (A), gradient (B), and curvature (C) terms. However, anisotropy, which exists in the real world, usually complicates AVO analysis. Recognizing anisotropic behavior on AVO crossplots can help avoid AVO interpretation errors. Using a modification to a three‐term (A, B, and C) approximation to the exact anisotropic reflection coefficients for transversely isotropic media, we find that anisotropy has a nonlinear effect on an A versus C crossplot yet causes slope changes and differing intercepts on A versus B or C crossplots. Empirical corrections that result in more accurate crossplot interpretation are introduced for specific circumstances.
Automatic event picking in prestack migrated gathers using a probabilistic neural network
Authors: Glinsky Michael E. , Clark Grace A. , Cheng Peter K. Z. , Devi K. R. Sandhya , Robinson James H. , Ford Gary E.
Published: October 2002

We describe algorithms for automating the process of picking seismic events in prestack migrated common depth image gathers. The approach uses supervised learning and statistical classification algorithms along with advanced signal/image processing algorithms. No model assumption is made, such as hyperbolic moveout. We train a probabilistic neural network for voxel classification using event times, subsurface points, and offsets (ground truth information) picked manually by expert interpreters. The key to success is using effective features that capture the important behavior of the measured signals. We test a variety of features calculated in a local neighborhood about the voxel under analysis. Selection algorithms ensure that we use only the features that maximize class separability. This event‐picking algorithm has the potential to reduce significantly the cycle time and cost of 3‐D prestack depth migration while making the velocity model inversion more robust.
Parsimonious 2‐D poststack Kirchhoff depth migration
Authors: Hua Biao‐Long , McMechan George A.
Published: October 2002

Efficiency of Kirchhoff migration can be much improved by using slope information from the seismic section to estimate the incident wave directions. Ray tracing is performed only back along the incident wave directions and so is much reduced. Unlike in conventional Kirchhoff implementations, there is no need to build traveltime tables, so relatively little memory and input/output use are required. Compression of the input data and restricting the contribution of each time sample to the image to lie within a Fresnel zone of its ray path further reduces the computation time. Synthetic and field data tests show that the new algorithm is about 30 times faster than traditional Kirchhoff migration for 2‐D poststack data. The main structural features may be imaged very quickly at the expense of some details. There is a tradeoff between speed and image quality; the optimal compromise is implemented by the choice of migration parameters.
Direct Fourier migration for vertical velocity variations
Authors: Margrave Gary F.
Published: October 2002

The Stolt f‐x migration algorithm is a direct (i.e. nonrecursive) Fourier‐domain technique based on a change of variables, or equivalently a mapping, that converts the unmigrated spectrum to the migrated spectrum. The algorithm is simple and efficient but limited to constant velocity. A v(z) f‐k migration method, capable of very high accuracy for vertical velocity variations, can be formulated as a nonstationary filter that avoids the change of variables. The result is a direct Fourier‐domain process that, for each wavenumber, applies a nonstationary migration filter to a vector of input frequency samples to create a vector of output frequency samples. The filter matrix is analytically specified in the mixed domain of input frequency and migrated time. It can be moved to the full‐Fourier domain of input frequency and output frequency by a fast Fourier transform. When applied for constant velocity, the v(z) f‐k algorithm is slower than the Stolt method but without the usual artifacts related to complex‐valued frequency‐domain interpolation. Vertical velocity variations, through an rms‐velocity (straight‐ray) assumption, are handled by the v(z) f‐k method with no additional cost. Greater accuracy at slight additional expense is obtained by extending the method to a WKBJ phase‐shift integral. This has the same accuracy as recursive phase shift and is similar in cost. For constant velocity, the full‐Fourier domain migration filter is a discrete approximation to a Dirac delta function whose singularity tracks along a hyperbola determined by the migration velocity. For variable velocity, the migration filter has significant energy between hyperbolic trajectories determined by the minimum and maximum instantaneous velocities. The full‐Fourier domain offers interesting conceptual parallels to Stolt’s algorithm. However, unless a more efficient method of calculating the Fourier filter matrix can be found, the mixed‐domain method will be faster. The mixed‐domain nonstationary filter moves the input data from the Fourier domain to the migrated time domain as it migrates. It is faster because the migration filter is known analytically in the mixed domain.
Scalar generalized‐screen algorithms in transversely isotropic media with a vertical symmetry axis
Authors: Le Rousseau Jéro⁁me H. , de Hoop Maarten V.
Published: October 2002

The scalar generalized‐screen method in isotropic media is extended here to transversely isotropic media with a vertical symmetry axis (VTI). Although wave propagation in a transversely isotropic medium is essentially elastic, we use an equivalent “acoustic” system of equations for the qP‐waves which we prove to be accurate for both the dispersion relation and the polarization angle in the case of “mild” anisotropy. The enhanced accuracy of the generalized‐screen method as compared to the split‐step Fourier methods allows the extension to VTI media. The generalized‐screen expansion of the one‐way propagator follows closely the method used in the isotropic case. The medium is defined in terms of a background and a perturbation. The generalized‐screen expansion of the vertical slowness is based upon an expansion of the medium parameters simultaneously into magnitude and smoothness of variation. We cast the theory into numerical algorithms, and assess the accuracy of the generalized‐screen method in a particular VTI medium with complex structure (the BP Amoco Valhall model) in which multipathing is significant.
Regional gravity setting of the Sudbury Structure
Authors: Hearst R. B. , Morris W. A.
Published: October 2002

In the vicinity of Sudbury, Ontario, Canada, the boundary between the Southern and Superior tectonic provinces is overlain by the elliptical Sudbury Structure. On the basis of gravity modeling, genesis of the Sudbury Structure has been attributed to either a magmatic origin (having a dense hidden differentiate zone) or a meteorite impact origin (there being no dense hidden mass). The difference between the two gravity models centers on the problem of regional‐residual separation. As shown by numerous previous studies, any such separation of components is nonunique. This becomes especially problematic when, as in Sudbury, a portion of the near‐surface geology has a similar orientation and dimension to more deep‐seated source. In this paper, several numerical methods (upward continuation, downward continuation, wavelength filtering, trend‐surface analysis) for determining the regional component of the gravity field associated with the Sudbury Structure have been applied and evaluated. Of the numerical methods used, the upward and downward continuation operators provided the most insight into the deep structural controls of the Sudbury Basin. Our preferred interpretation of the regional gravity field invokes a two‐component structure. Underlying the southern half of the Sudbury Structure is a laterally continuous gravity anomaly that is probably associated with a zone of uplifted Huronian volcanics. The gravity anomaly under the northern portion of the Sudbury Structure has a more restricted spatial extent. The close association between the northern limit of the gravity anomaly and the surface outcrop of the Levack Gneiss suggests the source of this anomaly is probably a slab of dense Levack Gneiss. This interpretation favors a meteorite impact origin for the Sudbury Structure.
Thin‐bed AVO: Compensating for the effects of NMO on reflectivity sequences
Authors: Castoro Alessandro , White Roy E. , Thomas Rhodri D.
Published: October 2002

Estimating the amplitude versus offset (AVO) gradient for thin beds is problematic because of offset‐dependent tuning and NMO stretch. When AVO analysis is carried out before NMO correction, the nonparallel nature of the NMO hyperbolas results in differential interference conditions at each offset and complicates AVO interpretation. If AVO analysis is carried out after NMO correction, the data bandwidth is distorted and corrections must be made to recover the true AVO response. A correction for NMO stretch can be applied to Fourier spectra obtained after windowing the NMO‐corrected prestack data. This approach requires knowledge of the seismic wavelet but seems to be relatively insensitive to noise in the data or uncertainties in the wavelet estimation. The technique allows the interference conditions to be made independent of offset and the correct AVO gradient relative to the normal incidence amplitude to be recovered.
Recording seismic reflections using rigidly interconnected geophones
Authors: Schmeissner C. M. , Spikes K. T. , Steeples D. W.
Published: October 2002

Ultrashallow seismic reflection surveys require dense spatial sampling during data acquisition, which increases their cost. In previous efforts to find ways to reduce these costs, we connected geophones rigidly to pieces of channel iron attached to a farm implement. This method allowed us to plant the geophones in the ground quickly and automatically. The rigidly interconnected geophones used in these earlier studies detected first‐arrival energy along with minor interfering seismic modes, but they did not detect seismic reflections. To examine further the feasibility of developing rigid geophone emplacement systems to detect seismic reflections, we experimented with four pieces of channel iron, each 2.7 m long and 10 cm wide. Each segment was equipped with 18 geophones rigidly attached to the channel iron at 15‐cm intervals, and the spikes attached to all 18 geophones were pushed into the ground simultaneously. The geophones detected both refracted and reflected energy; however, no significant signal distortion or interference attributable to the rigid coupling of the geophones to the channel iron was observed in the data. The interfering seismic modes mentioned from the previous experiments were not detected, nor was any P‐wave propagation noted within the channel iron. These results show promise for automating and reducing the cost of ultrashallow seismic reflection and refraction surveys.
Varying the effective mass of geophones
Authors: Spikes K. T. , Steeples D. W. , Schmeissner C. M. , Prado R. , Pavlovic M.
Published: October 2002

Traditionally, acquiring seismic data has rested on the assumption that geophone mass should be as small as possible. When Steeples and coworkers in 1999 planted 72 geophones automatically and simultaneously with a farm tillage implement, the effective mass of each of the geophones was significantly increased. We examined how the mass of a geophone affects changes in traveltime, amplitude, frequency, and overall data quality by placing various external masses on top of 100‐Hz vertical geophones. Circular barbell weights of 1.1‐, 11.3‐, and 22.7 kg; an 8.2‐kg bag of lead shot; and a 136‐kg stack of barbell weights were placed on top of geophones during data acquisition. In addition, a very large mass in the form of a truck was parked on top of two of the geophones. Four seismic sources supplying a broad range of energies were tested: a sledgehammer, a .22‐caliber rifle, a 30.06 rifle, and an 8‐gauge Betsy Seisgun. Spectral analysis revealed that the smaller weights had the greatest effects on the capacities of the geophones to replicate the earth’s motion. Consequently, using geophones with a large effective mass as part of an automatic geophone‐planting device would not necessarily be detrimental to the collection of high‐quality near‐surface seismic data.
Randomized Phase II Study of Cisplatin With Gemcitabine or Paclitaxel or Vinorelbine as Induction Chemotherapy Followed by Concomitant Chemoradiotherapy for Stage IIIB Non–Small-Cell Lung Cancer: Cancer and Leukemia Group B Study 9431
Authors: Vokes Everett E. , Herndon James E. , Crawford Jeffrey , Leopold Kenneth A. , Perry Michael C. , Miller Antonius A. , Green Mark R.
Published: October 2002

PURPOSE: To evaluate new drugs in combination with cisplatin in unresectable stage III non–small-cell lung cancer, Cancer and Leukemia Group B (CALGB) conducted a randomized phase II study of two cycles of induction chemotherapy followed by two additional cycles of the same drugs with concomitant radiotherapy.

PATIENTS AND METHODS: Eligible patients received four cycles of cisplatin at 80 mg/m2 on days 1, 22, 43, and 64 with arm 1: gemcitabine 1,250 mg/m2 on days 1, 8, 22, and 29 and 600 mg/m2 on days 43, 50, 64, and 71; arm 2: paclitaxel 225 mg/m2 for 3 hours on days 1 and 22 and 135 mg/m2 on days 43 and 64; and arm 3: vinorelbine 25 mg/m2 on days 1, 8, 15, 22, and 29 and 15 mg/m2 on days 43, 50, 64, and 71. Radiotherapy was initiated on day 43 at 2 Gy/d (total dose, 66 Gy).

RESULTS: One hundred seventy-five eligible patients were analyzed. Toxicities during induction chemotherapy consisted primarily of grade 3 or 4 granulocytopenia. Grade 3 or 4 toxicities during concomitant chemoradiotherapy consisted of thrombocytopenia, granulo-cytopenia, and esophagitis. Response rates after completion of radiotherapy were 74%, 67%, and 73% for arms 1, 2, and 3, respectively. Median survival for all patients was 17 months. One-, 2-, and 3-year survival rates for the patients on the three arms were 68%/37%/28%, 62%/29%/19%, and 65%/40%/23%.

CONCLUSION: Four cycles of gemcitabine, vinorelbine, or paclitaxel in combination with cisplatin can be administered at these doses and schedules. The observed survival rates exceed those of previous CALGB trials and may be attributable to the use of concomitant chemoradiotherapy. Induction chemotherapy added to concomitant chemoradiotherapy is being evaluated in a phase III randomized trial.
Family History and Prostate Cancer Screening With Prostate-Specific Antigen
Authors: Mäkinen Tuukka , Tammela Teuvo L.J. , Stenman Ulf-Håkan , Määttänen Liisa , Rannikko Sakari , Aro Jussi , Juusela Harri , Hakama Matti , Auvinen Anssi
Published: October 2002

PURPOSE: Early detection of prostate cancer has been recommended for men with affected first-degree relatives despite the lack of evidence for mortality reduction. We therefore evaluated the impact of family history in the Finnish prostate cancer screening trial.

PATIENTS AND METHODS: Approximately 80,000 men were identified from the population register for the first screening round. Of the 32,000 men randomized to the screening arm, 30,403 were eligible at the time of invitation. A blood sample was drawn from the participants (n = 20,716), and serum prostate-specific antigen (PSA) was determined. Men with a PSA level ≥ 4.0 ng/mL were referred for prostate biopsy. Information on family history was obtained through a self-administered questionnaire at baseline.

RESULTS: A total of 964 (5%) of the 20,716 screening participants had a positive family history, and 105 (11%) were screening-positive. Twenty-nine tumors were diagnosed, corresponding to a detection rate of 3.0% (29 of 964) and a positive predictive value of 28% (29 of 105). Of the 19,347 men without a family history, 1,487 (8%) had a PSA level ≥ 4.0 ng/mL. The detection rate was 2.4% (462 of 19,347) and the positive predictive value was 31% (462 of 1,487). The risk associated with a positive family history was not substantially increased (rate ratio, 1.3; 95% confidence interval, 0.9 to 1.8). The results were not affected by the age of the screenee or age at diagnosis of the affected relative. The program sensitivity was 6% (29 of 491) (ie, selective screening policy would have missed 94% of cancers in the population). No differences were seen in the characteristics of screen-detected cancers by family history.

CONCLUSION: Our findings provide no support for selective screening among men with affected relatives.
Salvage Cryotherapy for Recurrent Prostate Cancer After Radiotherapy: Variables Affecting Patient Outcome
Authors: Izawa Jonathan I. , Madsen Lydia T. , Scott Shellie M. , Tran Jean-Paul , McGuire Edward J. , von Eschenbach Andrew C. , Pisters Louis L.
Published: October 2002

PURPOSE: To determine the long-term disease-specific survival (DSS) and disease-free survival (DFS) rates after salvage cryotherapy for locally recurrent adenocarcinoma of the prostate and to identify pretreatment factors that have an impact on DSS and DFS.

PATIENTS AND METHODS: Between July 1992 and January 1995, 131 patients who had received definitive radiation therapy (XRT) underwent salvage cryotherapy for locally recurrent adenocarcinoma of the prostate. Cryotherapy failure was defined as an increasing postcryotherapy prostate-specific antigen (PSA) level of ≥ 2 ng/mL above the postcryotherapy nadir, a positive prostate biopsy, or radiographic evidence of metastatic disease. Clinical variables were studied to determine whether there was an association with the DSS and DFS.

RESULTS: The median follow-up was 4.8 years. The 5-year DSS rates were 87% for patients with a precryotherapy Gleason score ≤ 8 and 63% for those with Gleason scores of 9 and 10 (P = .012). The 5-year DFS rates were 57% for patients with a precryotherapy PSA level of ≤ 10 ng/mL and 23% for those with a PSA level greater than 10 ng/mL (P = .0004). The 5-year DSS rates for patients with a pre-XRT clinical stage of T1 to T2 and those with a clinical stage of T3 to T4 were 94% and 72%, respectively (P = .0041). The 5-year DFS rates for these groups were 90% and 69%, respectively (P = .0057).

CONCLUSION: Androgen-independent local recurrences, Gleason score, and pre-XRT clinical stage were important factors that had an impact on DSS and DFS. The subset of patients cured by salvage cryotherapy seems to be small, and patient selection is important.
Parallel fluid queues with constant inflows and simultaneous random reductions
Authors: Kella Offer , Miyazawa Masakiyo
Published: October 2002

We consider I fluid queues in parallel. Each fluid queue has a deterministic inflow with a constant rate. At a random instant subject to a Poisson process, random amounts of fluids are simultaneously reduced. The requested amounts for the reduction are subject to a general I-dimensional distribution. The queues with inventories that are smaller than the requests are emptied. Stochastic upper bounds are considered for the stationary distribution of the joint buffer contents. Our major interest is in finding exponential product-form bounds, which turn out to have the appropriate decay rates with respect to certain linear combinations of buffer contents.
Distribution of the scan statistic for a sequence of bistate trials
Authors: Fu James C.
Published: October 2002

Let be the scan statistic of window size r for a sequence of n bistate trials . The scan statistic Sn(r) has been successfully used in various fields of applied probability and statistics, and its distribution has been studied extensively in the literature. Currently, all existing formulae for the distribution of Sn(r) are rather complex, and they can only be numerically implemented when is a sequence of Bernoulli trials, the window size r is less than 20 and the length of the sequence n is not too large. Hence, these formulae have been limiting the practical applications of the scan statistic. In this article, we derive a simple and effective formula for the distribution of Sn(r) via the finite Markov chain embedding technique to overcome some of the limitations of the existing complex formulae. This new formula can be applied when is either a sequence of Bernoulli trials or a sequence of Markov dependent bistate trials. Selected numerical examples are given to illustrate our results.
A refinement of multivariate Bonferroni-type inequalities
Authors: Chen Tuhao , Seneta E.
Published: October 2002

Technology developed in a predecessor paper (Chen and Seneta (1996)) is applied to provide, in a unified manner, a sharpening of bivariate Bonferroni-type bounds on P(v1≥r, v2≥u) obtained by Galambos and Lee (1992; upper bound) and Chen and Seneta (1986; lower bound).
The correlated random walk with boundaries: A combinatorial solution
Authors: Böhm W.
Published: October 2002

The transition functions for the correlated random walk with two absorbing boundaries are derived by means of a combinatorial construction which is based on Krattenthaler's theorem for counting lattice paths with turns. Results for walks with one boundary and for unrestricted walks are presented as special cases. Finally we give an asymptotic formula, which proves to be useful for computational purposes.
Zero-temperature ising spin dynamics on the homogeneous tree of degree three
Authors: Howard C. Douglas
Published: October 2002

We investigate zero-temperature dynamics for a homogeneous ferromagnetic Ising model on the homogeneous tree of degree three (𝕋) with random (i.i.d. Bernoulli) spin configuration at time 0. Letting θ denote the probability that any particular vertex has a +1 initial spin, for infinite spin clusters do not exist at time 0 but we show that infinite ‘spin chains’ (doubly infinite paths of vertices with a common spin) exist in abundance at any time ϵ > 0. We study the structure of the subgraph of 𝕋 generated by the vertices in time-ϵ spin chains. We show the existence of a phase transition in the sense that, for some critical θc with spin chains almost surely never form for θ < θc but almost surely do form in finite time for θ > θc. We relate these results to certain quantities of physical interest, such as the t → ∞ asymptotics of the probability that any particular vertex changes spin after time t.
Multivariate semi-Markov analysis of burst properties of multiconductance single ion channels
Authors: Ball F. , Milne R. K. , Yeo G. F.
Published: October 2002

Patch clamp recordings from ion channels often show periods of repetitive activity, known as bursts, which are noticeably separated from each other by periods of inactivity. Depending on the type of channel, such recordings may exhibit (conductance) levels between the closed (zero) level and the fully open level. Properties of bursts are less subject to problems that arise from recording than are properties for individual sojourns at different levels, and study of bursting behaviour provides important information about the finer structure of the underlying channel gating process. For a general finite state space continuous-time Markov chain model allowing one or more nonzero conductance levels, the present paper establishes results about the semi-Markov structure of a single burst and of a sequence of bursts, and uses this in a unified approach to properties of both theoretical and empirical bursts. The distribution and moments of particular burst properties, including the total charge transfer, the total sojourn time and the total number of visits to specified conductance levels during a burst, are derived. Various extensions are also described.
On the nature of the binomial distribution
Authors: Vellaisamy P. , Punnen Abraham P.
Published: October 2002

We examine how the binomial distributionB(n,p) arises as the distributionSn= ∑i=1nXiof an arbitrary sequence of Bernoulli variables. It is shown thatB(n,p) arises in infinitely many ways as the distribution of dependent and non-identical Bernoulli variables, and arises uniquely as that of independent Bernoulli variables. A number of illustrative examples are given. The casesB(2,p) andB(3,p) are completely analyzed to bring out some of the intrinsic properties of the binomial distribution. The conditions under whichSnfollowsB(n,p), given thatSn-1is not necessarily a binomial variable, are investigated. Several natural characterizations ofB(n,p), including one which relates the binomial distributions and the Poisson process, are also given. These results and characterizations lead to a better understanding of the nature of the binomial distribution and enhance the utility.
Stochastic processes involving random deletion
Authors: Rothmann Mark D. , El Barmi Hammou
Published: October 2002

We consider a system where units having magnitudes arrive according to a nonhomogeneous Poisson process, remain there for a random period and then depart. Eventually, at any point in time only a portion of those units which have entered the system remain. Of interest are the finite time properties and limiting behaviors of the distribution of magnitudes among the units present in the system and among those which have departed from the system. We will derive limiting results for the empirical distribution of magnitudes among the active (departed) units. These results are also shown to extend to systems having stages or steps through which units must proceed. Examples are given to illustrate these results.
Shocks, runs and random sums
Authors: Mallor F. , Omey E.
Published: October 2002

In this paper we study random variables related to a shock reliability model. Our models can be used to study systems that fail when k consecutive shocks with critical magnitude (e.g. above or below a certain critical level) occur. We obtain properties of the distribution function of the random variables involved and we obtain their limit behaviour when k tends to infinity or when the probability of entering a critical set tends to zero. This model generalises the Poisson shock model.
High prevalence of endocrine dysfunction in long‐term survivors after allogeneic bone marrow transplantation for hematologic diseases
Authors: Tauchmanovà Libuse , Selleri Carmine , Rosa Gennaro De , Pagano Loredana , Orio Francesco , Lombardi Gaetano , Rotoli Bruno , Colao Annamaria
Published: October 2002

BACKGROUND

The progressively increasing number of long‐term survivors after allogeneic bone marrow transplantation (allo‐BMT) led researchers to focus on the early and late complications of this procedure. Endocrine dysfunction occurred mostly in patients who had undergone total body irradiation (TBI) as part of pretransplantation treatment. The extent to which chemotherapy and immune system derangement affect endocrine function in allo‐BMT recipients is still unclear.

METHODS

Forty consecutive patients (21 women, 19 men) with hematologic diseases surviving 12 or more months after allo‐BMT from HLA‐identical siblings were studied. Patients' age at transplantation ranged from 13 to 45 years and their post‐BMT follow‐up lasted 12–62 months. The conditioning regimen BUCY2 was employed. Graft versus host disease (GVHD) was observed in the acute form in 13 patients and in the chronic form in 26. The function of hypothalamic‐pituitary‐gonad, thyroid, somatotrophic, and adrenal axes was assessed.

RESULTS

The most common endocrine dysfunction was ovarian insufficiency (95% of women), followed by an increase in follicle‐stimulating hormone in 47% of men, indicating spermatogenesis damage. Hormone replacement therapy was contraindicated in three women because of chronic liver GVHD and it was ineffective partially in four others because of reduced intestinal or cutaneous absorption. Thyroid dysfunction occurred in 47.5% of patients and included low T3 syndrome, chronic thyroiditis, and transient subclinical hyperthyroidism and subclinical hypothyroidism. Adrenal function was abnormal in 10%, mostly related to the prolonged corticosteroid treatment. IGF‐I was lower than age‐reference values in 27% of all patients and in 38% of those with chronic GVHD. Thyroid, adrenal, and IGF‐I impairments were more frequent in patients with chronic GVHD than in patients without this disease (P = 0.048).

CONCLUSIONS

A high prevalence of endocrine dysfunction was detected in a cohort of allo‐BMT recipients not treated by TBI. Although gonadal failure was likely related to intensive myeloablative treatments, thyroid, adrenal, and IGF‐I impairments were late events, suggesting that immunosuppressive treatment and immune system derangement may play a role in the development of endocrine dysfunction after allografting. Cancer 2002;95:1076–84. © 2002 American Cancer Society.

DOI 10.1002/cncr.10773