bluuebunny/crossref_metadata_2025 huggingface dataset:
Release episodes at the periphery of gaps: a modeling assessment of gap impact extent
Authors: Ménard André , Dubé Patrick , Bouchard André , Marceau Danielle J
Published: October 2002

Gaps are recognized as important features of temperate forest dynamics and have been extensively studied in the last decades. Their definition has progressively evolved from the simplistic physical projection of the canopy opening to a more resource-based and functional approach (extended and species extended gaps). However, to truly define gap extent, the peripheral impact of gaps on the trees has to be considered. This study was undertaken to characterize the impact extent of gaps on their periphery using the SORTIE forest succession model. The sapling growth responses to gaps of different sizes (5002000 m2) was used as an indicator of the impact extent. Ten replicates of a simulation (for each gap size) were performed (305 years, 25-ha lattice). Gaps were introduced after 300 years. Growth ratios (pregap/postgap growth) for each sapling were computed and compared with a release threshold to determine sapling release episodes. These release episodes were analyzed to assess the extent of gap impact. Results indicate that gap effect extends significantly into the adjacent forest. Release episode orientations are concentrated in the northern hemisphere of gaps, and release episodes mostly appear in the first 20 m from gaps. Based on different degrees of release occurrence, new gap areas were defined and compared with areas from existing gap definitions. The differences are substantial and reveal that gap spatial extent observed through release patterns surpasses gap areas defined by traditional definitions.
QUANTUM-STATISTICAL SIMULATIONS FOR QUANTUM CIRCUITS
Authors: FISCHER KURT , MATUTTIS HANS-GEORG , ITO NOBUYASU , ISHIKAWA MASAMICHI
Published: October 2002

Using a Hubbard–Stratonovich like decomposition technique, we implemented simulations for the quantum circuits of Simon's algorithm for the detection of the periodicity of a function and Shor's algorithm for the factoring of prime numbers on a classical computer. Our approach has the advantage that the dimension of the problem does not grow exponentially with the number of qubits.
A SCHRÖDINGER BLACK HOLE AND ITS ENTROPY
Authors: SUDARSKY DANIEL
Published: October 2002

We discuss the conditions under which one can expect to have the usual identification of black hole entropy with the area of the horizon. We then construct an example in which the actual presence of the event horizon on a given hypersurface depends on a quantum event in which a certain quantum variable acquires a value and which occurs in the future of the given hypersurface. This situation indicates that there is something fundamental that is missing in the most popular of the current approaches towards the construction of a theory of quantum gravity, or, alternatively, that there is something fundamental that we do not understand about entropy in general, or at least in its association with black holes.
CRITICISM OF "NECESSITY OF SIMULTANEOUS CO-EXISTENCE OF INSTANTANEOUS AND RETARDED INTERACTIONS IN CLASSICAL ELECTRODYNAMICS" BY CHUBYKALO AND VLAEV
Authors: JACKSON J. D.
Published: October 2002

The demonstration that the electromagnetic fields derived from the Liénard–Wiechert potentials do not satisfy the Maxwell equations is proved to be false. Errors were made in the computation of the derivatives of retarded quantities. The subsequent inference of the necessity of both instantaneous and retarded electromagnetic interactions cannot be made. Different choices of gauge can lead to a variety of forms for the scalar and vector potentials, always with the same retarded fields. Classical electromagnetic theory is complete as usually expressed. One may choose to work in the Lorentz gauge in which all quantities are retarded.
MASS MATRICES AND EIGENSTATES FOR SCALARS/PSEUDOSCALARS: INDIRECT CP VIOLATION, MASS HIERARCHIES AND SYMMETRY BREAKING
Authors: MACHET B.
Published: October 2002

I study indirect CP violation for neutral kaons, and extend it to large values of the CP-violating parameter (taken to be real). I show how and at which condition there can exist a continuous set of basis in which the kinetic and mass terms in the Lagrangian can be diagonalized simultaneously. An ambiguity results for the mass spectrum, which then depends on the basis. In particular, for fixed (positive) (mass)2 of the CP eigenstates [Formula: see text], and for certain ranges of values of the CP-violating parameter, a negative (mass)2 can arise in the CP-violating basis. Under certain conditions, even a small perturbation, lifting the ambiguity, can drastically affect the pattern of masses.

These investigations extend in a natural way to indirect CP violation among a set of Higgs-like doublets.

The C-odd commutator [Formula: see text], or its equivalent for Higgs multiplets, plays an important role. The condition for its vanishing and its consequences are among the main concerns of this work.
ON GAUGE DYNAMICS AND SUSY BREAKING IN ORIENTIWORLD
Authors: KAKUSHADZE ZURAB
Published: October 2002

In the orientiworld framework the Standard Model fields are localized on D3-branes sitting on top of an orientifold three-plane. The transverse six-dimensional space is a noncompact orbifold (or a more general conifold). The four-dimensional gravity on D3-branes is reproduced due to the four-dimensional Einstein–Hilbert term induced at the quantum level. The orientifold three-plane plays a crucial role, in particular, without it the D3-brane world-volume theories would be conformal due to the tadpole cancellation. We study nonperturbative gauge dynamics in various [Formula: see text] supersymmetric orientiworld models based on the Z3 as well as Z5 and Z7 orbifold groups. Our discussions illustrate that there is a rich variety of supersymmetry preserving dynamics in some of these models. On the other hand, we also find some models with dynamical supersymmetry breaking.
TWO LARGE EXAMPLES IN ORBIFOLD THEORY: ABELIAN ORBIFOLDS AND THE CHARGE CONJUGATION ORBIFOLD ON ${\mathfrak{su}}(n)$
Authors: HALPERN M. B. , OBERS N. A.
Published: October 2002

Recently the operator algebra and twisted vertex operator equations were given for each sector of all WZW orbifolds, and a set of twisted KZ equations for the WZW permutation orbifolds were worked out as a large example. In this companion paper we report two further large examples of this development. In the first example we solve the twisted vertex operator equations in an Abelian limit to obtain the twisted vertex operators and correlators of a large class of Abelian orbifolds. In the second example, the twisted vertex operator equations are applied to obtain a set of twisted KZ equations for the (outer-automorphic) charge conjugation orbifold on [Formula: see text].
GRAVITON-PHOTON CONVERSION ON SPIN 0 AND 1/2 PARTICLES
Authors: RAVNDAL FINN , SUNDBERG MATS
Published: October 2002

The differential cross-sections for scattering of gravitons into photons on bosons and fermions are calculated in linearized quantum gravity. They are found to be strongly peaked in the forward direction and become constant at high energies. Numerically, they are very small as expected for such gravitational interactions.
Inhibition of constitutively active forms of mutant kit by multitargeted indolinone tyrosine kinase inhibitors
Authors: Liao Albert T. , Chien May B. , Shenoy Narmada , Mendel Dirk B. , McMahon Gerald , Cherrington Julie M. , London Cheryl A.
Published: October 2002

Mutations in the proto-oncogene c-kit, including point mutations, deletions, or duplications in the negative regulatory juxtamembrane (JM) domain or point mutations in the catalytic domain, have been observed in human and canine cancers and often result in constitutive activation of Kit in the absence of ligand binding. To identify a receptor tyrosine kinase (RTK) inhibitor capable of blocking the function of mutant Kit, we evaluated 3 indolinones (SU11652, SU11654, and SU11655) that act as competitive inhibitors of adenosine triphosphate binding to several members of the split kinase family of RTKs, including VEGFR, FGFR, PDGFR, and Kit. Mast cell lines expressing either wild-type (WT) Kit, a point mutation in the JM domain, a tandem duplication in the JM domain, or a point mutation in the catalytic domain were used for these studies. All 3 indolinones inhibited phosphorylation of WT Kit in the presence of stem cell factor at concentrations as low as 0.01 μM. Autophosphorylation of both JM mutants was inhibited at 0.01 to 0.1 μM, resulting in cell cycle arrest within 24 hours, whereas autophosphorylation of the catalytic domain mutant was inhibited at 0.25 to 0.5 μM, resulting in cell death within 24 hours. poly(ADP-ribose) polymerase (PARP) cleavage was noted in all Kit mutant lines after indolinone treatment. In summary, SU11652, SU11654, and SU11655 are effective RTK inhibitors capable of disrupting the function of all forms of mutant Kit. Because the concentrations of drug necessary for receptor inhibition are readily achievable and nontoxic in vivo, these compounds may be useful in the treatment of spontaneous cancers expressing Kit mutations.
Pretargeting radioimmunotherapy of a murine model of adult T-cell leukemia with the α-emitting radionuclide, bismuth 213
Authors: Zhang Meili , Yao Zhengsheng , Garmestani Kayhan , Axworthy Donald B. , Zhang Zhuo , Mallett Robert W. , Theodore Louis J. , Goldman Carolyn K. , Brechbiel Martin W. , Carrasquillo Jorge A. , Waldmann Thomas A.
Published: October 2002

We used a pretargeting technique to treat a nonobese diabetic/severe combined immunodeficient murine model of human adult T-cell leukemia with an anti-Tac antibody-streptavidin (HAT-SA) conjugate, which recognizes CD25, followed by bismuth 213 (213Bi)-1,4,7,10-tetraazacyclododecane-N,N′,N′′,N′′′-tetraacetic acid (DOTA)- biotin. In the 3-step pretargeting radioimmunotherapy protocol, HAT-SA (140 or 400 μg) was administered intravenously (i.v.) to bind to the interleukin 2 receptor α (IL-2Rα; CD25)–expressing tumor cells. After 24 hours, 100 μg of a synthetic clearing agent was administered i.v. to remove unbound circulating HAT-SA conjugate from the circulation. Four hours later,213Bi–DOTA-biotin was administered i.v. for therapy. Tumor growth was significantly inhibited in 3 trials by using 250 μCi (9.25 MBq) of 213Bi–DOTA-biotin with a pretargeting technique as monitored by serum levels of soluble IL-2Rα and/or human β-2-microglobulin (P < .05, t test) and by survival of tumor-bearing mice in the treatment groups (P < .02, log rank test) as compared with the control groups. No prolongation of survival was observed with a nonspecific antibody-SA conjugate or in the absence of the radionuclide. Additionally, no prolongation of survival resulted from administration of 213Bi directly linked to intact HAT. Furthermore, there was no prolongation of survival when the β-emitting radionuclide yttrium 90 instead of the α-emitting radionuclide213Bi was used. The pretargeting approach with213Bi inhibited tumor growth more effectively than did immunotherapy with unmodified HAT. The best results were obtained with combination therapy that involved 213Bi–DOTA-biotin with a pretargeting technique supplemented by 4 weekly doses of HAT. The findings of this study support the use of this combination approach in a clinical trial in patients with IL-2Rα–expressing leukemias.
Anemia of chronic disease in rheumatoid arthritis is associated with increased apoptosis of bone marrow erythroid cells: improvement following anti–tumor necrosis factor-α antibody therapy
Authors: Papadaki Helen A. , Kritikos Heraklis D. , Valatas Vasilis , Boumpas Dimitrios T. , Eliopoulos George D.
Published: October 2002

Circumstantial evidence has implicated tumor necrosis factor α (TNF-α) in the pathogenesis of anemia of chronic disease (ACD) in rheumatoid arthritis (RA). We investigated the role of TNF-α in erythropoiesis of patients with active RA (n = 40) and the effect of anti–TNF-α antibody administration (cA2). Patients with RA had lower numbers of CD34+/CD71+ and CD36−/glycophorin A+ (glycoA+) bone marrow (BM) cells and increased proportions of apoptotic cells within the CD34+/CD71+ and CD36+/glycoA+ cell compartments, compared to healthy controls (n = 24). Erythroid burst-forming units (BFU-Es) obtained by BM mononuclear or purified CD34+ cells were significantly lower in RA patients compared to controls. These abnormalities were more pronounced among patients with ACD. Increased TNF-α levels in patient long-term BM culture supernatants inversely correlated with BFU-Es and hemoglobin levels and positively with the percentage of apoptotic CD34+/CD71+ and CD36+/glycoA+ cells. Following cA2 therapy, a normalization was documented in the number of CD34+/CD71+ and CD36−/glycoA+ cells, the number of BFU-Es, and the proportion of apoptotic CD34+/CD71+ and CD36+/glycoA+ cells, which was associated with a significant increase in hemoglobin levels compared to baseline. Recovery from anemia was more prominent in patients with ACD. The exogenous addition of an anti–TNF-α antibody in the cultures increased BFU-E number in patients prior to cA2 treatment but not after treatment, further substantiating the inhibitory role of TNF-α on patients' erythropoiesis. We conclude that TNF-α–mediated apoptotic depletion of BM erythroid cells may account for ACD in RA and that cA2 administration may ameliorate ACD in these patients by down-regulating the apoptotic mechanisms involved in erythropoiesis.
Heterozygous PU.1 mutations are associated with acute myeloid leukemia
Authors: Mueller Beatrice U. , Pabst Thomas , Osato Motomi , Asou Norio , Johansen Lisa M. , Minden Mark D. , Behre Gerhard , Hiddemann Wolfgang , Ito Yoshiaki , Tenen Daniel G.
Published: October 2002

The transcription factor PU.1 is required for normal blood cell development. PU.1 regulates the expression of a number of crucial myeloid genes, such as the macrophage colony-stimulating factor (M-CSF) receptor, the granulocyte colony-stimulating factor (G-CSF) receptor, and the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor. Myeloid cells derived from PU.1−/− mice are blocked at the earliest stage of myeloid differentiation, similar to the blast cells that are the hallmark of human acute myeloid leukemia (AML). These facts led us to hypothesize that molecular abnormalities involving the PU.1 gene could contribute to the development of AML. We identified 10 mutant alleles of the PU.1 gene in 9 of 126 AML patients. The PU.1 mutations comprised 5 deletions affecting the DNA-binding domain, and 5 point mutations in 1) the DNA-binding domain (2 patients), 2) the PEST domain (2 patients), and 3) the transactivation domain (one patient). DNA binding to and transactivation of the M-CSF receptor promoter, a direct PU.1 target gene, were deficient in the 7 PU.1 mutants that affected the DNA-binding domain. In addition, these mutations decreased the ability of PU.1 to synergize with PU.1-interacting proteins such as AML1 or c-Jun in the activation of PU.1 target genes. This is the first report of mutations in the PU.1 gene in human neoplasia and suggests that disruption of PU.1 function contributes to the block in differentiation found in AML patients.
Efficient gene transfer into human primary blood lymphocytes by surface-engineered lentiviral vectors that display a T cell–activating polypeptide
Authors: Maurice Marielle , Verhoeyen Els , Salmon Patrick , Trono Didier , Russell Stephen J. , Cosset François-Loı̈c
Published: October 2002

In contrast to oncoretroviruses, lentiviruses such as human immunodeficiency virus 1 (HIV-1) are able to integrate their genetic material into the genome of nonproliferating cells that are metabolically active. Likewise, vectors derived from HIV-1 can transduce many types of nonproliferating cells, with the exception of some particular quiescent cell types such as resting T cells. Completion of reverse transcription, nuclear import, and subsequent integration of the lentivirus genome do not occur in these cells unless they are activated via the T-cell receptor (TCR) or by cytokines or both. However, to preserve the functional properties of these important gene therapy target cells, only minimal activation with cytokines or TCR-specific antibodies should be performed during gene transfer. Here we report the characterization of HIV-1–derived lentiviral vectors whose virion surface was genetically engineered to display a T cell-activating single-chain antibody polypeptide derived from the anti-CD3 OKT3 monoclonal antibody. Interaction of OKT3 IgGs with the TCR can activate resting peripheral blood lymphocytes (PBLs) by promoting the transition from G0 to G1 phases of the cell cycle. Compared to unmodified HIV-1–based vectors, OKT3-displaying lentiviral vectors strongly increased gene delivery in freshly isolated PBLs by up to 100-fold. Up to 48% transduction could be obtained without addition of PBL activation stimuli during infection. Taken together, these results show that surface-engineered lentiviral vectors significantly improve transduction of primary lymphocytes by activating the target cells. Moreover these results provide a proof of concept for an approach that may have utility in various gene transfer applications, including in vivo gene delivery.
Increased soluble and platelet-associated CD40 ligand in essential thrombocythemia and reactive thrombocytosis
Authors: Viallard Jean-François , Solanilla Anne , Gauthier Bruno , Contin Cécile , Déchanet Julie , Grosset Christophe , Moreau Jean-François , Praloran Vincent , Nurden Paquita , Pellegrin Jean-Luc , Nurden Alan T. , Ripoche Jean
Published: October 2002

CD40 ligand (CD40L) is expressed on activated CD4+ T lymphocytes and at the activated platelet surface. A circulating soluble form of CD40L (sCD40L) is generated by the way of a proteolytic cleavage. We measured sCD40L in the plasma of either healthy subjects; patients with inflammatory disorders and low, normal, or high platelet count (reactive thrombocytosis); or patients with essential thrombocythemia (ET). A tight correlation was found between the platelet count and plasma sCD40L. ET patients had the highest levels of sCD40L. Platelet-associated CD40L was increased in ET and reactive thrombocytosis, conditions associated with increased platelet regeneration. Platelet-associated CD40L was released upon platelet activation. In conclusion, platelets appear as a reservoir of CD40L that may be a major contributor to circulating sCD40L. Platelet-associated CD40L may be a potential marker of platelet regeneration.
Association of CD34 cell dose with hematopoietic recovery, infections, and other outcomes after HLA-identical sibling bone marrow transplantation
Authors: Bittencourt Henrique , Rocha Vanderson , Chevret Sylvie , Socié Gérard , Espérou Hélène , Devergie Agnès , Dal Cortivo Liliane , Marolleau Jean-Pierre , Garnier Federico , Ribaud Patricia , Gluckman Eliane
Published: October 2002

Although CD34 cell dose is known to influence outcome of peripheral stem cell– and/or T-cell–depleted transplantation, such data on unmanipulated marrow transplantation are scarce. To study the influence of CD34+ cell dose on hematopoietic reconstitution and incidence of infections after bone marrow transplantation, we retrospectively analyzed 212 patients from January 1994 to August 1999 who received a transplant of an unmanipulated graft from an HLA-identical sibling donor. Median age was 31 years; 176 patients had hematologic malignancies. Acute graft-versus-host disease prophylaxis consisted mainly in cyclosporin associated with methotrexate (n = 174). Median number of bone marrow nucleated cells and CD34+ cells infused were 2.4 × 108/kg and 3.7 × 106/kg, respectively. A CD34+ cell dose of 3 × 106/kg or more significantly influenced neutrophil (hazard ratio [HR] = 1.37, P = .04), monocyte (HR = 1.47, P = .02), lymphocyte (HR = 1.70, P = .003), erythrocyte (HR = 1.77, P = .0002), and platelet (HR = 1.98,P = .00008) recoveries. CD34+ cell dose also influenced the incidence of secondary neutropenia (HR = 0.60,P = .05). Bacterial and viral infections were not influenced by CD34 cell dose, whereas it influenced the incidence of fungal infections (HR = 0.41, P = .008). Estimated 180-day transplantation-related mortality (TRM) and 5-year survival were 25% and 56%, respectively, and both were highly affected by CD34+ cell dose (HR = 0.55, P = .006 and HR = 0.54, P = .03, respectively). Five-year survival and 180-day TRM were, respectively, 64% and 19% for patients receiving a CD34+ cell dose of 3 × 106/kg or more and 40% and 37% for the remainders. In conclusion a CD34+ cell dose of 3 × 106/kg or more improved all hematopoietic recoveries, decreased the incidence of fungal infections and TRM, and improved overall survival.
HBED ligand: preclinical studies of a potential alternative to deferoxamine for treatment of chronic iron overload and acute iron poisoning
Authors: Bergeron Raymond J. , Wiegand Jan , Brittenham Gary M.
Published: October 2002

We have continued the preclinical evaluation of the efficacy and safety of the hexadentate phenolic aminocarboxylate iron chelatorN, N′-bis(2-hydroxybenzyl) ethylenediamine-N, N′-diacetic acid monosodium salt (NaHBED) for the treatment of both chronic transfusional iron overload and acute iron poisoning. We examined the effect of route of administration by giving equimolar amounts of NaHBED and deferoxamine (DFO) to Cebus apella monkeys as either a subcutaneous (SC) bolus or a 20-minute intravenous (IV) infusion. By both routes, NaHBED was consistently about twice as efficient as DFO in producing iron excretion. For both chelators at a dose of 150 μmol/kg, SC was more efficient than IV administration. The biochemical and histopathologic effects of NaHBED administration were assessed. No systemic toxicity was found after either IV administration once daily for 14 days to iron-loaded dogs or after SC administration every other day for 14 days to dogs without iron overload. Evidence of local irritation was found at some SC injection sites. When the NaHBED concentration was reduced to 15% or less in a volume comparable to a clinically useful one, no local irritation was found with SC administration in rats. Because treatment of acute iron poisoning may require rapid chelator infusion, we compared the effects of IV bolus administration of the compounds to normotensive rats. Administration of DFO produced a prompt, prolonged drop in blood pressure and acceleration of heart rate; NaHBED had little effect. NaHBED may provide an alternative to DFO for the treatment of both chronic transfusional iron overload and of acute iron poisoning.
Unrelated marrow transplantation for children with acute lymphoblastic leukemia in second remission
Authors: Bunin Nancy , Carston Michael , Wall Donna , Adams Roberta , Casper James , Kamani Naynesh , King Roberta ,   the National Marrow Donor Program Working Group
Published: October 2002

Allogeneic bone marrow transplantation (BMT) may be curative for more patients than chemotherapy for the child with relapsed acute lymphoblastic leukemia. This study reviewed the outcomes of 363 children with acute lymphoblastic leukemia in second remission who received unrelated donor BMT from 1988 to 2000 in order to define prognostic factors that affect leukemia-free survival (LFS). Median patient age was 9 years (range, 0-19 years), and median follow-up 29 was months (range, 0-125 months). The median duration of first remission was 24 months (range, 0-109 months). Prognostic factors, including age, duration of first remission, HLA matching, and graft-versus-host (GVH) disease, were analyzed using both univariate and multivariate analyses. Overall survival was 38%, and LFS was 36% at 5 years. LFS was significantly worse for patients 15 years or older (log-rank, P = .009). HLA matching was associated with improved LFS. Acute GVH disease developed in 71%, with 29% having grades III-IV. The incidence of chronic GVH disease was 39% for patients who survived more than 80 days and was significantly higher for female patients receiving marrow from female donors (P = .0009). Transplantation-related mortality was 42% and was associated with HLA mismatches, age 15 years and older, and first remission less than 12 months. The 5-year estimate for relapse was 22%, with first remission at least 6 months associated with a lower risk. Results of unrelated donor BMT appear similar to multi-institutional studies of matched related donor BMT, and this approach appears to be curative for many patients. However, innovative approaches are needed for patients with initial remissions of less than 6 months and for older teenagers.
Vitamin C inhibits granulocyte macrophage–colony-stimulating factor–induced signaling pathways
Authors: Cárcamo Juan M. , Bórquez-Ojeda Oriana , Golde David W.
Published: October 2002

Vitamin C is present in the cytosol as ascorbic acid, functioning primarily as a cofactor for enzymatic reactions and as an antioxidant to scavenge free radicals. Human granulocyte macrophage–colony-stimulating factor (GM-CSF) induces an increase in reactive oxygen species (ROS) and uses ROS for some signaling functions. We therefore investigated the effect of vitamin C on GM-CSF–mediated responses. Loading U937 cells with vitamin C decreased intracellular levels of ROS and inhibited the production of ROS induced by GM-CSF. Vitamin C suppressed GM-CSF–dependent phosphorylation of the signal transducer and activator of transcription 5 (Stat-5) and mitogen-activated protein (MAP) kinase (Erk1 and Erk2) in a dose-dependent manner as was phosphorylation of MAP kinase induced by both interleukin 3 (IL-3) and GM-CSF in HL-60 cells. In 293T cells transfected with alpha and beta GM-CSF receptor subunits (αGMR and βGMR), GM-CSF–induced phosphorylation of βGMR and Jak-2 activation was suppressed by vitamin C loading. GM-CSF–mediated transcriptional activation of a luciferase reporter construct containing STAT-binding sites was also inhibited by vitamin C. These results substantiate the importance of ROS in GM-CSF signaling and indicate a role for vitamin C in downmodulating GM-CSF signaling responses. Our findings point to vitamin C as a regulator of cytokine redox-signal transduction in host defense cells and a possible role in controlling inflammatory responses.
RELATION BETWEEN FIRING CURRENT AND PERFORMANCE IN SEISMOGRAPH CAPS
Authors: Burrows L. A.
Published: October 2002

The time break characteristics of both “SS” and “SSS” seismograph caps are discussed. Particular attention is given to the occurrence, length, and uniformity of the various time breaks over a relatively extensive range of firing currents. At the higher firing currents, the “SSS” caps do not show the “induction period” characteristic of “SS” caps, and at the lower firing currents, the “total cap lag” of the “SSS” cap is less than that of the “SS.” Thus the “bridge break” and the “total cap lag” of this newer product are not only shorter, but they are more uniform than those of the older product (“SS” caps).
AN EXPERIMENTAL STUDY OF THE ELASTIC PROPERTIES OF ROCKS
Authors: Ide J. M.
Published: October 2002

Laboratory determinations of Young’s modulus, rigidity, and compressibility were made on a set of representative rock samples. These measurements are compared with the theoretical relations between the elastic constants of an isotropic medium. Computed longitudinal and transverse wave velocities are compared with direct field measurements by Leet in granite and norite. Agreement is within 5 per cent for norite, and 20 per cent for granite.
WORKING DEPTHS FOR LOW FREQUENCY ELECTRICAL PROSPECTING
Authors: Lewis William Bradley
Published: October 2002

Electrical measurements were made on the surface of the earth with low frequency commutated current using nineteen separate frequencies and six electrode separations. Analysis of the data indicates that there is an effect of appreciable magnitude attributable to an interface 6000 feet below the surface.
THE INTERPRETATION OF WELL SHOT DATA—II
Authors: Dix C. Hewitt
Published: October 2002

Five methods of shooting a well for the determination of vertical velocity, and the methods of reduction of the data, are discussed. Means are described for determining the existence of interference due to transmission of vibration down the cable which suspends the well geophone.
COMMUNICATIONS AND DISCUSSIONS
Authors: Rust W. M.
Published: October 2002

Dr. W. M. Rust, Jr., 1944–45, President of the Society of Exploration Geophysicists, has prepared at the editor’s request the following account of the hearings of the Federal Communications Commission which were attended by him and Dr. B. B. Weatherby.
“GEOPHYSICS IN NATIONAL DEFENSE”: AN ESMWT COURSE CONDUCTED AT THE COLORADO SCHOOL OF MINES
Authors: Tripp R. Maurice
Published: October 2002

In the October 1944 issue of Geophysics, Mr. M. D. Dobrin gave a report of a course in petroleum geophysics which he very ably conducted in Washington, D. C., under the auspices of the ESMWT and sponsored by George Washington University for fifteen weeks following May 1, 1944.
STUDIES ON SEISMIC WAVES: II. RAYLEIGH WAVES IN A SUPERFICIAL LAYER
Authors: Fu C. Y.
Published: October 2002

Lamb’s method in the theory of the plate is extended to the case in which one of the surfaces is not free. The resulting determinantal relation is similar to that of Sezawa. It is then simplified and special cases of the frequency‐velocity relation are discussed. Even when the thickness of the layer is as small as a wave length, the interaction of the upper and lower boundaries of the layer is quite slight and Rayleigh waves and Stoneley’s waves may be discussed separately. A few points in connection with the application of this frequency relation to the ground roll problem are also discussed.
STUDIES ON SEISMIC WAVES: I. REFLECTION AND REFRACTION OF PLANE WAVES
Authors: Fu C. Y.
Published: October 2002

By taking the apparent velocity along the boundary as the parameter instead of the angle of incidence, the equations for the different wave amplitudes may be put in more symmetrical forms. In this way, it is more convenient to discuss both the body waves and the Rayleigh waves at the same time. A difficulty in the plotting of the square root of the wave intensity against the angles is also discussed. When the reflection or refraction coefficient is not real, the meaning of the intensity, as obtained by squaring the absolute value of the latter quantity, needs clarification.
NOTES ON SHOT POINT PROCEDURE
Authors: Williams F. J.
Published: October 2002

Some characteristics of seismic explosives are reviewed, and an attempt is made to outline optimum shot point procedure from the standpoint of efficiency, safety and quality of data. Care in preparation of charges is stressed, with special emphasis on adequate cap firing currents and charge assemblies. Suggestions are made in regard to the choice of the location for the up‐hole time seismometer. It is concluded that adherence to well‐defined specific shot point procedures is essential to the procurement of highest quality recordings.
THE GEOLOGY AND GEOPHYSICS OF THE ODEM OIL FIELD, SAN PATRICIO COUNTY, TEXAS
Authors: McCarver Holland , West Lloyd G.
Published: October 2002

The Odem field, located in southern San Patricio County, Texas, was discovered in the latter part of 1939. Prior to 1933, the Odem area received a limited amount of geological and geophysical exploration, and several test wells were drilled. These tests were dry and the area apparently condemned until a reflection seismograph survey indicated structure. Subsequent drilling confirmed the presence of a structure containing several producing horizons. The proven limits of production conformed closely to the contours of the original seismograph map.
GEOPHYSICAL HISTORY OF THE TEN SECTION OIL FIELD, KERN COUNTY, CALIFORNIA
Authors: Waterman Joseph C.
Published: October 2002

The Ten Section oil field, generally regarded as the first geophysical oil field discovery in the San Joaquin Valley of California, was found by Shell Oil Company, Incorporated by means of a reflection seismograph survey made in 1934–1935. The discovery well, Shell Oil Company, Incorporated’s K. C. L.-Stevens A-1, was completed in June, 1936. A map presenting results of reflection shooting before discovery and one from well data with contours on the top of the productive Upper Miocene “Stevens” sand are shown.
DISCUSSION—MULTIPLE REFLECTIONS
Authors: Dresbach C. H.
Published: October 2002

In various places along the east side of the San Joaquin Valley, roughly thirty miles north of Bakersfield, reflected events have been observed that plotted below the known top of the basement. Sufficient well and velocity data are available to locate them quite closely. From what is known of the character of the basement material, it appears unlikely that the rather smoothly plotting, fairly continuous events could originate from within the basement. The conclusion is therefore forced that they must represent multiple events of some sort.
ELECTRICAL SURVEYS OF SOME SHALLOW SALT DOMES
Authors: Lewis W. Bradley
Published: October 2002

Consideration of the perturbation potentials associated with geological features indicates the superiority of gap‐measurements over in‐phase measurements. Measurements of the gap‐potential over two Gulf Coast salt domes show sharp anomalies readily correlated with known geology.
A NEW METHOD OF INTERPRETATION OF SELF‐POTENTIAL FIELD DATA
Authors: de Witte L.
Published: October 2002

In this paper a new, efficient method is worked out for the interpretation of self‐potential field data. Interpretation of location, depth and dip of the ore body is made, using a pattern of equipotential lines. The negative center and the positive maximum of the potential are found and also the so‐called “mid‐value” point. The dip α, can be determined accurately for values between 5° and 85°. The method cannot be used for vertical polarization. The depth and location can be found with relative accuracy for α>10°. The main advantage of this new method is the ease of interpretation and a greater accuracy for the high‐dip angles. It should be stressed that, for correct and accurate interpretation, the positive maximum is as important as the negative center. Therefore, it should be carefully sought during the field work, and mapped to its full extent.
ADDITION TO SYMPOSIUM ON “GEOPHYSICS IN MINING”
Authors: Koschmann A. H.
Published: October 2002

Several speakers have referred to the applicability of the magnetic method of geophysical prospecting in areas of pyrrhotite bodies. Experience in the Kokomo district, Colorado, suggests that a word of caution is necessary. Massive bodies of pyrrhotite occur in the Kokomo district as replacement bodies in limestone. The U. S. Bureau of Mines, in the course of a preliminary investigation of geophysical work in that area, made magnetic measurements to determine whether or not the presence of these known pyrrhotite bodies could be detected.
GEOPHYSICAL DEVELOPMENTS IN EUROPE DURING THE WAR
Authors: Vajk Raoul
Published: October 2002

Intensive geophysical activity took place in many of the European countries during the war. However, as corresponding literature is inadequate and hardly accessible, not much was published here on this subject. The writer has compiled some information obtained from various sources and, though they are still incomplete, believes that the most important geophysical surveys made in Europe during the war are covered by the following data.
THE COMPUTATION OF SECOND VERTICAL DERIVATIVES OF GEOMAGNETIC FIELDS
Authors: Henderson Roland G. , Zietz Isidore
Published: October 2002

Second vertical derivatives of magnetic fields, because of their high resolving power, are often very useful in interpreting magnetic anomalies. Formulas are developed which permit their ready numerical computation. Comparisons are made between the resulting approximate values and the rigorous values obtained for simple idealized fields. The similarity between maps of second vertical derivatives of fields and those of certain types of residual fields is discussed.
THE UPWARD CONTINUATION OF ANOMALIES IN TOTAL MAGNETIC INTENSITY FIELDS
Authors: Henderson Roland G. , Zietz Isidore
Published: October 2002

In airborne magnetometry consideration must be given to the necessity of multi‐level observations. The problem of computing total intensity anomalies from data observed on lower levels is investigated in the case of contours exhibiting both two‐ and three‐dimensional features. It is found that even fairly complex anomalies can be extended, with results differing but slightly from observations at the higher level. Maps for comparing computed and observed anomalies are presented. The mathematical basis is given together with numerical formulas and procedures for affecting the computations.
A SUBSTITUTION METHOD FOR THE ABSOLUTE CALIBRATION OF VIBRATION PICK‐UPS
Authors: Haskell Norman A.
Published: October 2002

By making use of the general relations between input and output currents and voltages in four‐terminal networks of bilateral impedances a relationship is derived between the velocity response of a reversible vibration pick‐up and the velocity output of the same device, when used as a source of mechanical vibrations. It is then shown that any vibration pick‐up may be calibrated in absolute terms as a function of frequency by purely electrical measurements (input current and output voltage) made on the given pick‐up, an auxiliary reversible pick‐up, and a variable frequency driver.
INTERPRETATION OF SPONTANEOUS POLARIZATION ANOMALIES CAUSED BY SPHEROIDAL OREBODIES
Authors: Yüngül Sulhi
Published: October 2002

The theoretical case of a polarized hidden sphere is discussed briefly. To determine location, depth and dip of an orebody displaying natural currents a method of practical value is explained and a master diagram is given. A distinction is made between anomalies which can be treated assuming a polarized sphere and those which can not be interpreted this way. A generalized method of topographical and regional correction is given. The procedure of interpretation and topographical correction is shown with two field examples. The method is not empirical and the results are precise when applied to the cases in which the assumption of a sphere is justified. It is shown that topographical corrections can not be overlooked.
REGIONAL GEOLOGY AND GEOPHYSICS OF THE ARK‐LA‐TEX AREA
Authors: Bryan Carl L.
Published: October 2002

The boundaries of the Ark‐La‐Tex area are arbitrarily defined and the exploration history of the area briefly reviewed. A Basal Upper Cretaceous structure map and two stratigraphic cross sections illustrate the regional tectonic movements contributing to the formation of the East Texas basin, the North Louisiana basin and the intervening Sabine Uplift. Exploration objectives and problems and the relation of magnetic and gravity anomalies and axes with regional geologic trends and structure are discussed. It is pointed out that the piercement dome type structure offers an almost untested field for further exploration. Illustrations include a vertical intensity magnetic map with contour interval of 100 gammas, a Bouguer gravity map with contour interval of 5 milligals and type seismograph records.
STUDIES IN NON‐STRUCTURAL PETROLEUM PROSPECTING I. A NON‐STRUCTURAL WORKING HYPOTHESIS FOR PETROLEUM PROSPECTING
Authors: Rosaire E. E.
Published: October 2002

A non‐structural (i.e., more general than structural) working hypothesis, with a potential usefulness greater than that of the currently accepted geophysical structural working hypothesis, is proposed for petroleum prospecting. This non‐structural working hypothesis postulates that an observable anomaly, with potential significance in petroleum prospecting, may originate not only in lithologic structure (the significant structural anomaly), but also in stratigraphic variations in (primary) lithology associated with the presence of petroleum accumulation (the significant stratigraphic anomaly). Thereby, a gradation in types of significant anomalies is anticipated, from the significant structural to the significant stratigraphic anomaly, depending upon the relative magnitudes of structural and stratigraphic effects. Two sub‐hypotheses are formulated, the special structural and the special stratigraphic, which are applicable, respectively, to the resolution of the significant structural and the significant stratigraphic anomalies. An examination of the corollaries from the hypotheses at issue (the currently accepted geophysical structural and the proposed non‐structural) indicates that one critical test depends upon the identification of four unique (i.e., unfamiliar) characteristics postulated for the near‐surface significant stratigraphic anomaly; these are magnitude at a shallow depth of survey, configuration, orientation of maximum expression, and change in configuration with depth of survey.
A SEISMIC REFLECTION QUALITY MAP OF THE UNITED STATES
Authors: Lyons Paul L.
Published: October 2002

A reflection‐quality map of the United States has been prepared by a subcommittee of the Program and Arrangements Committee for 1950–51. The map designates as good, fair, or poor to NG all sedimentary areas of the United States in respect to reflection quality in seismic explorations. The map may be used in the planning of seismograph operations. Reflection quality is a function of many factors.
GEOPHYSICAL EXPLORATION IN WESTERN CANADA
Authors: Houghton H. M.
Published: October 2002

This paper is restricted to a statistical study and to operational problems which are peculiar to the bush country of northwestern Alberta.
AN ELECTROMECHANICAL TRANSDUCER SYSTEM FOR THE TRANSIENT TESTING OF SEISMOGRAPHS
Authors: Honnell Pierre M.
Published: October 2002

The transient response of seismographs is probably the more important instrumental characteristic of these devices and may be computed analytically subject to some simplifications. Recourse to direct laboratory tests would be a useful procedure for determining this type of response, both as a check on the theory and for the development applications. Many early devices designed to test seismographs dynamically were rather crude affairs and aptly named “shaking tables.” However, the prior art discloses with apparently but a single exception no shaking table truly capable of reproducing transient motions other than the natural oscillations of the device itself. The purpose of this paper is to describe the theory and construction of an electromechanical transducer system which does reproduce vertical mechanical motions in the image of arbitrarily specified waveforms for the transient testing of seismographs. Results of such tests on commercial seismometers is included.
THE GULF AIRBORNE MAGNETIC GRADIOMETER
Authors: Wickerham W. E.
Published: October 2002

An instrument capable of measuring magnetic gradients as encountered in airborne magnetometer operations has possible applications as an interpretational aid. Its usefulness, particularly for qualitative analysis, will be discussed briefly. The design of a spatial‐type airborne gradiometer of adequate precision can be shown to be quite impractical. An instrument based on the time derivative of the magnetic intensity variations provides a useful alternative and is described.
SOME GEOMETRICAL PROPERTIES OF RESIDUAL MAPS
Authors: Swartz Charles A.
Published: October 2002

From well known mathematical theory it can be demonstrated that most contour maps may be considered to be built up by the superposition of a double infinity of elementary undulating surfaces, each of which has the form of a horizontal sinusoidally corrugated sheet, infinite in extent. These elementary surfaces may have all possible wave lengths, orientations, amplitudes, and phases. Several examples are given of simple mosaic‐type composite maps built up by combining only two such elementary surfaces in different ways. These resemble geophysical contour maps in many significant respects. Residual maps are often prepared by using a template procedure for computing the residual value at any point as a linear combination of several neighborhood values interpolated from the original map. An expression is derived for the Fourier transform of any residual map prepared in this way. This transform gives the amplitude spectrum of the residual map in terms of the amplitude spectrum of the original map and the geometry of the template pattern. It is applied to the special case of an original map of the two‐component mosaic variety mentioned above. The results are presented quantitatively in the form of attenuation, or filter, curves which show the amplitudes of the residual anomalies for various sizes and shapes of original anomalies, and for several different residual templates. The geometrical significance of “second derivative” maps is discussed, and it is shown that they may be prepared by a process which is a limiting case of applying a residual template pattern of very simple type. Attenuation curves are presented for several kinds of residual templates when applied to an idealized original contour map consisting of a single anomaly of various shapes. These filter curves are very similar to those for original maps of the simple mosaic type. It is concluded that, since most geophysical maps may be considered to be of a kind intermediate between these two extreme types, the attenuation curves given here may be useful for designing residual templates which will have desired selective characteristics.
LEAST SQUARES POLYNOMIAL FITTING TO GRAVITATIONAL DATA AND DENSITY PLOTTING BY DIGITAL COMPUTERS
Authors: Simpson Stephen M.
Published: October 2002

The fitting of a nth order polynomial in x and y to gravity data by least squares is discussed. A consideration of the normal equations for the general case shows certain simplifications resulting from rectangularity in data distribution. Some sample residual maps are constructed. Density plotting, made possible by the digital computer, is described and illustrated. It is shown that this process can serve as a substitute for contouring when only a qualitative picture is desired.
ON THE RELATION BETWEEN TELLURIC CURRENTS AND THE EARTH’S MAGNETIC FIELD
Authors: Wait James R.
Published: October 2002

The validity of Cagniard’s analysis of the behaviour of telluric earth currents is questioned in view of the fact that the harmonic components of the electric field and the magnetic field tangential to the ground are only proportional to one another if the fields are sufficiently slowly varying over the surface of the ground. His result is extended to include the effects of a layered ground with both conductivity and susceptibility variations. Finally the corresponding transient problem is solved for a two‐layer horizontally stratified earth.