Showing papers by "Tulane University published in 1981"
TL;DR: In this paper, the self-interaction correction (SIC) of any density functional for the ground-state energy is discussed. But the exact density functional is strictly selfinteraction-free (i.e., orbitals demonstrably do not selfinteract), but many approximations to it, including the local spin-density (LSD) approximation for exchange and correlation, are not.
Abstract: The exact density functional for the ground-state energy is strictly self-interaction-free (i.e., orbitals demonstrably do not self-interact), but many approximations to it, including the local-spin-density (LSD) approximation for exchange and correlation, are not. We present two related methods for the self-interaction correction (SIC) of any density functional for the energy; correction of the self-consistent one-electron potenial follows naturally from the variational principle. Both methods are sanctioned by the Hohenberg-Kohn theorem. Although the first method introduces an orbital-dependent single-particle potential, the second involves a local potential as in the Kohn-Sham scheme. We apply the first method to LSD and show that it properly conserves the number content of the exchange-correlation hole, while substantially improving the description of its shape. We apply this method to a number of physical problems, where the uncorrected LSD approach produces systematic errors. We find systematic improvements, qualitative as well as quantitative, from this simple correction. Benefits of SIC in atomic calculations include (i) improved values for the total energy and for the separate exchange and correlation pieces of it, (ii) accurate binding energies of negative ions, which are wrongly unstable in LSD, (iii) more accurate electron densities, (iv) orbital eigenvalues that closely approximate physical removal energies, including relaxation, and (v) correct longrange behavior of the potential and density. It appears that SIC can also remedy the LSD underestimate of the band gaps in insulators (as shown by numerical calculations for the rare-gas solids and CuCl), and the LSD overestimate of the cohesive energies of transition metals. The LSD spin splitting in atomic Ni and $s\ensuremath{-}d$ interconfigurational energies of transition elements are almost unchanged by SIC. We also discuss the admissibility of fractional occupation numbers, and present a parametrization of the electron-gas correlation energy at any density, based on the recent results of Ceperley and Alder.
16,027 citations
TL;DR: Methylation of eukaryotic DNA has been proposed to function in many ways, including control of transcription, maintenance of chromosome structure, repair of DNA, establishment of preferred sites for mutation, oncogenic transformation, and, in certain systems, protection of DNA against enzymatic degradation.
Abstract: A small portion of the cytosine residues in the DNA of higher eukaryotes as well as in that of many lowe eukaryotes if methylated. The resulting 5-methylcytosine residues occur in specific in the DNA, usually adjacent to guanine residues on the 3' side. This methylation of eukaryotic DNA has been proposed to function in many ways, including control of transcription, maintenance of chromosome structure, repair of DNA, establishment of preferred sites for mutation, oncogenic transformation, and, in certain systems, protection of DNA against enzymatic degradation.
674 citations
TL;DR: These agents were effective in disaggregating platelets and attenuating aggregation and were associated with a concomitant rise in cigarette smoke, which contains nitric oxide.
621 citations
TL;DR: In this article, a model of intra-industry trade within a multi-product industry whose output range is limited to that obtainable from a particular type of capital is presented.
575 citations
TL;DR: Intracellular recordings from pairs of neurons in slices of rat hippocampus directly demonstrate electrotonic coupling between neurons in the mammalian brain and indicate that some fast prepotentials are coupling potentials.
Abstract: Intracellular recordings from pairs of neurons in slices of rat hippocampus directly demonstrated electronic coupling between CA3 pyramidal cells. When two neurons were impaled simultaneously (as verified by subsequent double staining with horseradish peroxidase), current pulses injected into one cell caused voltage changes in other cells. These interactions were bidirectional. Fast prepotentials, historically thought to represent spike activity in dendrites, resulted from action potentials in other electronically coupled pyramidal cells. These data directly demonstrate electrotonic coupling between neurons in the mammalian brain and indicate that some fast prepotentials are coupling potentials. Coupling between pyramidal cells could mediate synchronization of normal rhythmic activity and of burst discharges during seizures.
320 citations
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276 citations
255 citations
TL;DR: In this paper, the finite-temperature Hartree-Fock-Bogoliubov (FTHFB) equations were derived and the solution of the FTBCS equations for the degenerate model displays a temperature-dependent pairing "phase transition".
210 citations
TL;DR: Push-out tests on the removed femurs reveal that those implants residing in cortical bone exhibited significantly higher shear properties than the equivalent implants in cancellous bone and that the interfacial shear strength and stiffness decreased with increasing pore diameter within the range 175-325 microns.
Abstract: The interfacial shear properties of bone tissue growth into porous coated Ti-6A1-4V femoral implants have been examined as a function of the pore size of the porous surface. Three particle size range powders (297 μm, 420–500 μm, 595–707 μm) were used to fabricate cylindrical implants which were inserted into the femoral medullary canal of dogs for 6 months. Push-out tests on the removed femurs are reported and reveal: (i) that those implants residing in cortical bone exhibited significantly higher shear properties than the equivalent implants in cancellous bone and (ii) that the interfacial shear strength and stiffness decreased with increasing pore diameter within the range 175–325 μm. The extent of bone ingrowth into the surface of the implants was measured using quantitative optical microscopic techniques. This indicated that the percentage of bone which had grown into the surface was inversely proportional to the square root of the pore size and that further the shear properties of the interface were proportional to the extent of bone in-growth.
199 citations
TL;DR: The results suggest that warfarin may be useful in the treatment of SCCL and also support the hypothesis that the blood coagulation mechanism may be involved in the growth and spread of cancer in man.
Abstract: In a controlled, randomized study, survival of patients with small cell carcinoma of the lung (SCCL) was prolonged on addition of warfarin sodium to combination chemotherapy plus radiation therapy. Median survival for 25 control patients was 24 weeks and for 25 warfarin-treated patients was 50 weeks. This difference could not be accounted for by differences between groups in performance status, extent of disease, age, or sex. The survival advantage associated with warfarin administration was observed both for patients with extensive disease and for those who failed to achieve complete or partial remission. The warfarin-treated group also demonstrated a significantly increased time to first evidence of disease progression. These results suggest that warfarin may be useful in the treatment of SCCL and also support the hypothesis that the blood coagulation mechanism may be involved in the growth and spread of cancer in man. ( JAMA 1981;245:831-835)
197 citations
TL;DR: Ashkins et al. as mentioned in this paper compared police, newspaper, television, and public images of crime trends for the seven FBI index crimes over time, the relative frequency of occurrence of these offenses, and the characteristics of persons committing them.
Abstract: This paper compares police, newspaper, television, and public images of crime trends for the seven FBI index crimes over time, the relative frequency of occurrence of these offenses, and the characteristics of persons committing them. Media presentations of crime trends over time are found generally Linrelated to trends in police statistics. Newspaper presentation of the relative distribution of crimes approximates police figures more closely than does the television presentation. Public views of the relative distribution of crimes but not of crime trends more closely approximate media presentations than police presentations. Television's impact on public views of crime is apparently minor. Reasons for these findings and their implications for crime news reporting are discussed. Joseph F. Sheley is Assistant Professor of Sociology at Tulane University. Cindy D. Ashkins is a juvenile justice and child protection services consultant in Fairfield, Connecticut. The New Orleans Police Department provided crime statistics for this study, and the managements of television Channels 4, 6, and 8 in New Orleans provided access to files of past news scripts. The authors gratefully acknowledge this assistance. Public Opinion Quarterly Vol. 45:492-506 ? 1981 by The Trustees of Columbia Univelsity Published by Elsevier North-Holland, Inc. 0033-362X/81X0045-492/$2.50 This content downloaded from 157.55.39.127 on Mon, 27 Jun 2016 06:08:27 UTC All use subject to http://about.jstor.org/terms CRIME, CRIME NEWS, AND CRIME VIEWS 493 papers daily, 64 percent of the sample report reliance on television as their primary source of news about political and current events. Forty-seven percent watch local newscasts frequently. Yet, despite television's popularity, we know little about its crime-reporting practices and less about the extent to which its picture of crime mirrors those of the police, the print media, and the public. This research examines all four images of crime in New Orleans, Louisiana, comparing their respective presentations of (1) crime trends for the seven major index crimes over time, (2) the relative frequency of occurrence of these offenses, and (3) the characteristics of persons committing them.
TL;DR: In this paper, error estimates for splitting algorithms are developed which are uniform in the viscosity v as it becomes small for either two or three-dimensional fluid flow in all of space.
Abstract: Viscous splitting algorithms are the underlying design principle for many numerical algorithms which solve the Navier-Stokes equations at high Reynolds number. In this work, error estimates for splitting algorithms are developed which are uniform in the viscosity v as it becomes small for either twoor three-dimensional fluid flow in all of space. In particular, it is proved that standard viscous splitting converges uniformly at the rate C^lAt, Strang-type splitting converges at the rate CP(At)2, and also that solutions of the Navier-Stokes and Euler equations differ by Cp in this case. Here C depends only on the time interval and the smoothness of the initial data. The subtlety in the analysis occurs in proving these estimates for fixed large time intervals for solutions of the Navier-Stokes equations in two space dimensions. The authors derive a new long-time estimate for the two-dimensional NavierStokes equations to achieve this. The results in three space dimensions are valid for appropriate short time intervals; this is consistent with the existing mathematical theory.
TL;DR: Intracellular injection of the fluorescent dye Lucifer Yellow into single magnocellular neurons in slices of rat hypothalamus resulted in dye transfer between these cells, suggesting that some mammalian neuropeptidergic cells are electrotonically coupled, providing a possible means for recruitment and synchronization of their electrical activity.
Abstract: Most magnocellular neurosecretory cells that terminate in the posterior pituitary secrete either vasopressin, oxytocin, or enkephalin. Intracellular injection of the fluorescent dye Lucifer Yellow into single magnocellular neurons in slices of rat hypothalamus resulted in dye transfer between these cells. Freeze-fracture replicas of these cells occasionally revealed gap junctions, which presumably contain channels that mediate the dye coupling. These two independent techniques strongly suggest that some mammalian neuropeptidergic cells are electrotonically coupled, providing a possible means for recruitment and synchronization of their electrical activity.
TL;DR: Using a pulse transmission ultrasound method, the elastic properties of bone samples taken from along the length and around the periphery of a bovine femur are determined using nine of the orthotropic elastic constants.
Abstract: Using a pulse transmission ultrasound method, we have determined the elastic properties of bone samples taken from along the length and around the periphery of a bovine femur. Twenty specimens, in the form of 5-mm cubes, were tested. All nine of the orthotropic elastic constants were determined for each specimen. Analysis of our data indicate that there are statistically significant variations from the usual assumption of transverse isotropy.
TL;DR: It is suggested that stimulation by GH of somatostatin release into hypophysial portal blood may be involved in the mechanism by which GH regulates its own secretion.
Abstract: The effects of GH on the release of somatostatin from the hypothalamus were assessed by measuring the concentrations of immunoreactive somatostatin (IRS) in hypophysial portal blood of urethane-anesthetized male rats. A significant and dose-related increase of IRS in hypophysial portal blood was observed during 20–80 min after a single injection of rat GH (5 and 25 μg) into the third ventricle. An intraventricular injection of ovine LH or vehicle alone did not affect IRS values in hypophysial portal blood. When rat GH was repeatedly injected into the cerebral ventricle at 75-min intervals, IRS in hypophysial portal blood rose following each injection in a similar pattern with a latency of 30–45 min. These findings suggest that the release of somatostatin from the hypothalamus is regulated, at least in part, by GH. Furthermore, in view of the inhibitory effect of somatostatin on GH secretion, stimulation by GH of somatostatin release into hypophysial portal blood may be involved in the mechanism by which G...
TL;DR: This study demonstrates that cleavage of the C-terminus tetrapeptide brings about a 10-fold decrease in opiate binding potency of either camel or human beta-endorphin.
TL;DR: Administration of a single intramuscular dose of 1.5, 2.0, or 3.0 mg levonantradol or placebo to 56 patients with moderate to severe postoperative or trauma pain showed significant analgesic effects as compared to placebo, however, no significant dose response was observed.
Abstract: Double-blind administration of a single intramuscular dose of 1.5, 2.0, 2.5, or 3.0 mg levonantradol or placebo to 56 patients with moderate to severe postoperative or trauma pain showed significant analgesic effects of each dose of levonantradol as compared to placebo (P less than 0.05). However, no significant dose response was observed. Compared to 2/16 patients on placebo, 23/40 patients (57 per cent) on levonantradol reported one or more side effect. Drowsiness was most frequent. Dry mouth, dizziness, "weird dreams," mild hallucinations, nervousness, apprehension and confusion occurred less frequently. Changes in resting heart rate and blood pressure were minor and general acceptability was good.
TL;DR: It is concluded that the periodicity of circadian activity systematically varies as a function of the stage of the estrous cycle and in a manner that cannot be solely explained by corresponding alterations in endogenous estrogen.
TL;DR: While disease‐free interval appeared to be improved in the 25% of patients onDTIC therapy who developed thrombocytopenia, the overall effect of postoperative DTIC therapy was apparently not beneficial (P < 0.05).
Abstract: A prospectively randomized study of postoperative chemotherapy with dimethyl triazeno imidazole carboxamide (DTIC) was conducted by the Central Oncology Group from 1972 until 1976. Of 174 patients operated upon for melanoma and entered into the study, 87 were randomly selected to receive DTIC, four courses in 12 months, at 4.5 mg/kg/d x 10. One-hundred-sixty-five (95%) of the cases were evaluable, including 40 high risk Stage I, 96 Stage II, and 29 Stage III cases. At a median follow-up period of 2.5 years, the control group had a better median disease-free interval (40 weeks vs. 73 weeks), median survival time (103 weeks vs. 133 weeks), and percentage of patients living free of disease (28% vs. 44%) than the DTIC-treated group. While disease-free interval appeared to be improved in the 25% of patients on DTIC therapy who developed thrombocytopenia, the overall effect of postoperative DTIC therapy was apparently not beneficial (P less than 0.05).
TL;DR: In this paper, a simple and accurate analytic model is derived for the correlation energy of any atom or ion within three density functional approximations based on the uniform electron gas: the local-spin density approximation (LSD), the selfinteraction corrected (SIC) version of LSD, and the antiparallel-spin LSD of Stoll et al.
Abstract: A simple and accurate analytic model is derived for the correlation energy of any atom or ion within three densityfunctional approximations based on the uniform electron gas: the local-spin-density approximation (LSD), the selfinteraction corrected (SIC) version of LSD, and the antiparallel-spin LSD of Stoll et al. The last two approximations give good results for the correlation energies of neutral atoms, in contrast to LSD which overestimates these energies by a factor of 2. However, all three approximations show an incorrect $\mathrm{ln}Z$ leading behavior when the nuclear charge $Z$ tends to infinity at fixed electron number $N$. It is hard to see how any a priori electron-gas approximation can reproduce the exact leading behavior, which is constant or linear in $Z$ according to the value of $N$.
TL;DR: The reduced response to PMA observed in neutrophils from patients on CHD may explain, at least in part, the increased susceptibility to infection in these patients.
TL;DR: Gynecologists should consider advising premenopausal women considering hysterectomy on the risks of coronary heart disease following the procedure, pending further elucidation of this phenomenon.
TL;DR: The 41-residue corticotropin releasing factor (CRF) was synthesized by the solid phase method and significantly stimulated release of ACTH-like immunoreactivity in a dose-related manner from rat pituitary quarters.
TL;DR: It is suggested that humoral immunologic abnormalities are not directly responsible for the lung changes in silicosis and cannot be used as "guides" to predict severity or progression of disease.
Abstract: Serum specimens from 53 patients with silicosis were examined for the presence of antinuclear antibodies (ANA), rheumatoid factor (RF), immunoglobulins, and immune complexes. These humoral immunologic parameters were compared with radiographic changes and pulmonary function studies. A significant percentage of patients had an increased prevalence of ANA, RF, and immunoglobulin elevation (IgG, IgA). Immune complexes determined by the Raji-cell assay were detected in 31% of the patients. However, there was no significant correlation between any humoral immunologic abnormality and radiographic changes or declines in pulmonary function tests. These findings suggest that humoral immunologic abnormalities are not directly responsible for the lung changes in silicosis and cannot be used as "guides" to predict severity or progression of disease.
TL;DR: In this article, the reduction/oxidation ratio of cytochrome c oxidase (cytochrome a,a3) was measured with polarographic microelectrodes and the redox state of the enzyme with a dual wavelength reflectance spectrophotometer.
TL;DR: Sucrose density gradient analysis was utilized to determine whether 1,25-dihydroxyvitamin D3 receptors are present in the rat uterus and low levels of the receptor seemed to bepresent in the unprimed uterus.
TL;DR: Theoretical predictions of surface bone remodeling in the diaphysis of a long bone under a constant superposed compressive load are made and it is shown that there is a great variety of solutions to the problem.
TL;DR: In this paper, a set of empirical studies is widely interpreted as supporting a high degree of indigenous community rejection of the mentally ill, and an examination of the conceptual structure underlying these studies indicates bias in favor of a rejection interpretation; the same data can be interpreted as reflecting a high level of indigenous acceptance.
Abstract: Successful re-integration of former psychiatric patients into the community rests upon social acceptance of such persons. A set of empirical studies is widely interpreted as supporting a high degree of indigenous community rejection of the mentally ill. An examination of the conceptual structure underlying these studies indicates bias in favor of a rejection interpretation; the same data can be interpreted as reflecting a high degree of indigenous acceptance. Analysis of new evidence on social acceptance of the mentally ill within a community dominated by the presence of a state mental hospital indicates that social acceptance of the mentally ill is positively related to exposure to psychiatric processing systems. When differences in measurement within the research design are considered, it appears that exposure to inpatient treatment systems may also lead to greater community optimism about the effectiveness of such systems. The analyses support an incremental pattern of community acceptance of psychiatric patients with the accumulation of exposure over time.
TL;DR: The first observation that lung may have functions other than respiratory was made in this century and subsequent work has established the many and variegated nonrespiratory functions of this organ.