Showing papers by "Lawrence Berkeley National Laboratory published in 1982"
TL;DR: A formal method of deciding which points are on the initial linear part of the curve is described, and a statistical method is proposed for analyzing these points, which provides a very satisfactory, robust method for the standard analysis of Salmonella data.
Abstract: A number of recent papers have suggested basing the statistical analysis of Salmonella (Ames) mutagenicity test results on a mathematical model of the complete dose-response curve. For most mutagens at low doses the curve increases linearly; then, as the dose increases, the curve may flatten and finally turn downwards due primarily to effects of toxicity. The exact mechanism underlying this shape is, however, not well understood and is likely to vary for different chemicals. A different approach is to assume that the initial part of the curve is linear and to base the statistical analysis solely on this region, reasoning that it contains most of the interpretable information about the mutagenesis dose response. In this paper a formal method of deciding which points are on the initial linear part of the curve is described, and a statistical method is proposed for analyzing these points. Computer simulations are used to examine the properties of the procedure and comparisons are made with a previously proposed mathematical model of the whole curve. It is concluded that the method suggested here provides a very satisfactory, robust method for the standard analysis of Salmonella data.
396 citations
TL;DR: In this paper, the interaction of CO with a potassium covered Pt(111) surface was investigated using thermal desorption (TDS), high resolution electron energy loss (HREELS) and ultraviolet photoelectron (UPS) spectroscopies.
209 citations
TL;DR: In this paper, it was demonstrated that the ab initio pseudopotential theory within the local density functional formalism provides an accurate theoretical framework for the study of lattice-dynamical properties of solids.
Abstract: It is demonstrated that the ab initio pseudopotential theory within the local-density-functional formalism provides an accurate theoretical framework for the study of lattice-dynamical properties of solids. With the use of atomic numbers and masses of constituent elements and the crystal structure as the only input information, the calculated phonon frequencies and mode-Gr\"uneisen parameters at $\ensuremath{\Gamma}$ and $X$, the third-order force constant for LTO ($\ensuremath{\Gamma}$), the shear modulus, and the zone-center TA [110] velocity are all in excellent agreement with experiment. Comparison with other microscopic calculations is made.
202 citations
TL;DR: In this article, the authors describe the development of an aethalometer that can measure aerosol absortion in real time, which can be used for real-time analysis.
Abstract: The authors describe the development of an aethalometer. This portable device measures aerosol absortion in real time. (AIP)
157 citations
147 citations
TL;DR: In this article, the authors test existing M/sub s/ formulae with measured M/Sub s/-composition data collected over the past 15 years in alloy design programs at Berkeley.
Abstract: The aim of the investigation is to test existing M/sub s/ formulae with measured M/sub s/-composition data collected over the past 15 years in alloy design programs at Berkeley. The maximum total composition of alloying elements is about 21 wt pct, and the maximum individual elemental compositions are 0.5 pct C, 12.2 pct Cr, 2.1 pct Mn, 12.5 pct Ni, 4.2 pct Mo, 3.2 pct Si, and 9 pct Co. These values are beyond the composition limit allowed by existing formulae. However, this investigation involves examining the validity of predicting M/sub s/ temperatures in the high alloy as well as low alloy range. 33 refs.
141 citations
TL;DR: In this article, the LEED pattern of C3 and C4 hydrocarbon adsorption on the Pt(111) face was studied by observing LEED patterns that formed and by measuring the intensity versus voltage spectra for each structure.
131 citations
TL;DR: The ab initio norm-conserving pseudopotential is generated from a reference atomic configuration in which the pseudoatomic eigenvalues and wave functions outside the core region agree with the corresponding all-electron results within the density-functional formalism as discussed by the authors.
Abstract: The ab initio norm-conserving pseudopotential is generated from a reference atomic configuration in which the pseudoatomic eigenvalues and wave functions outside the core region agree with the corresponding ab initio all-electron results within the density-functional formalism. This paper explains why such pseudopotentials accurately reproduce the all-electron results in both atoms and in multiatomic systems. In particular, a theorem is derived to demonstrate the energy- and perturbation-independent properties of ab initio pseudopotentials.
129 citations
01 Apr 1982
TL;DR: This chapter discusses the analysis of tensed statements in natural language and the need for a realistic world model to include representations not only for snapshot descriptions of the real world, but also for histories, or the evolution of such descriptions over time.
Abstract: Numerous researchers in a handful of disciplines have been concerned, in recent years, with the special role (or roles) that time seems to play in information processing. Designers of computerized information systems have had to deal with the fact that when an information item becomes outdated, it need not be forgotten. Researchers in artificial intelligence have pointed to the need for a realistic world model to include representations not only for snapshot descriptions of the real world, but also for histories, or the evolution of such descriptions over time. Many logicians have regarded classical logic as an awkward tool for capturing the relationships and the meaning of statements involving temporal reference, and have proposed special "temporal logics" for this purpose. Finally, the analysis of tensed statements in natural language is a principal concern of researchers in linguistics.
121 citations
TL;DR: It appears that the characteristic age responses seen in the wild-type CHO are associated with the function of an essentially error-free repair process, and a variation in the ability of this repair process to act in eliminating potentially lethal and mutagenic lesions would account for most of the age response.
Abstract: The cell-cycle response for killing and mutation induction by ultraviolet irradiation was measured in synchronous Chinese hamster ovary cells (CHO wild-type) and in a UV-hypersensitive mutant (43-3B) derived from this line. The CHO 43-3B line shows a greatly enhanced sensitivity to killing ( D 0 of 0.3 as compared to 3.2 J/m 2 for the wild-type), is hypermutable, and deficient in DNA repair. For the wild-type, a characteristic age response is seen for killing by UV, with maximum sensitivity in early-S and resistance increasing through the S-phase. There is also a life-cycle specificity for induction of diphteria-toxin resistance in late-G 1 and early-S. Relatively little variation is seen through the cell cycle for induced 6-thioguanine and ouabain resistance. In contrast, the 43-3B cell line shows a relatively ‘flat’ response to UV throughout the cell cycle, for both killing and mutation induction. Therefore it appears that the characteristic age responses seen in the wild-type CHO are associated with the function of an essentially erro-free repair process. A variation in the ability of this repair process to act in eliminating potentially lethal and mutagenic lesions (either due to a variation in repair enzyme activities through the cell cycle, or in the time available for repair) would account for most of the age response which is seen in the wild-type for killing and mutation induction by ultraviolet light.
108 citations
TL;DR: It is shown that while the photothermal signal is significantly affected in the case of highly scattering media, it is independent of scattering for optically thin samples, e.g., photoacoustic and photothermal deflection.
Abstract: We present a general unified theoretical analysis of the role of scattering in photothermal spectroscopy, e.g., photoacoustic and photothermal deflection. We show that while the photothermal signal is significantly affected in the case of highly scattering media, it is independent of scattering for optically thin samples. Numerical estimates of the scattering contribution and comparison with experimental results are given. We also elucidate the relationship between photothermal and diffuse reflectance spectroscopies.
TL;DR: Adding cholera toxin to human mammary epithelial cultures derived from reduction mammoplasties and primary carcinomas greatly stimulated cell growth and increased the number of times the cells could be successfully subcultured.
Abstract: Addition of cholera toxin to human mammary epithelial cultures derived from reduction mammoplasties and primary carcinomas greatly stimulated cell growth and increased the number of times the cells could be successfully subcultured. Other agents known to increase intracellular cAMP levels were also growth stimulatory. The increased growth potential conferred by cholera toxin enhances the usefulness of this cell culture system.
01 May 1982
TL;DR: In this paper, the economic worthiness of a conservation measure is expressed in terms of the cost of conserved energy, and a measure is considered economical when the cost is less than the price of the energy it replaces.
Abstract: Supply curves of conserved energy provide an accounting framework that expresses the potential for energy conservation. The economic worthiness of a conservation measure is expressed in terms of the cost of conserved energy, and a measure is considered economical when the cost of conserved energy is less than the price of the energy it replaces. A supply curve of conserved energy is independent of energy prices; however, the economical reserves of conserved energy will depend on energy prices. Double-counting of energy savings and error propagation are common problems when estimating conservation potentials, but supply curves minimize these difficulties and make their consequences predictable. The sensitivity of the cost of conserved energy is examined, as are variations in the optimal investment strategy in response to changes in inputs. Guidelines are presented for predicting the consequences of such changes. The conservation supply curve concept can be applied to peak power, water, pollution, and other markets where consumers demand a service rather than a particular good.
TL;DR: Quantitative studies at the BEVALAC have demonstrated some of the physical and radiobiological factors that promise to make accelerated heavy ions important for the therapy of cancer.
Abstract: Quantitative studies at the BEVALAC have demonstrated some of the physical and radiobiological factors that promise to make accelerated heavy ions important for the therapy of cancer. The measured physical dose-biological effect relationships allow the safe and effective delivery of therapeutic schedules of heavy ions. Among the charged particle beams available, carbon, neon and helium ions in the “extended Bragg peak mode” have optimal physical and biological effectiveness for delivery of therapy to deep seated tumors. The depth-dose profiles of these beams protect intervening and adjacent tissues as well as tissues beyond the range of the particles. For the treatment of hypoxic tumors, silicon and argon beams are being considered because they significantly depress the radiobiological oxygen effect in the region of the extended Bragg ionization peak. The depth-effectiveness of the argon beam is somewhat limited, however, because of primary particle fragmentation. Silicon beams have a depth-dose profile which is intermediate between that of neon and argon, and are candidates to become the particle of choice for maximizing high LET particle effects. Heavy accelerated ions depress enzymatic repair mechanisms, decrease variations of radiosensitivity during the cell division cycle, cause greater than expected delays in cell division, and decrease the protective effects of neighboring cells in organized systems. Near the Bragg peak, enhancement of heavy particle effects are observed in split dose schedules. Late and carcinogenic effects are being studied. With the newly developed Repair-Misrepair theory we can quantitatively model most observations.
Stanford University1, CERN2, Harvard University3, Vanderbilt University4, General Electric5, University of California, Santa Barbara6, Hewlett-Packard7, Lawrence Berkeley National Laboratory8, Fermilab9, Alcatel-Lucent10, University of Paris11, IBM12, University of California, Berkeley13, Pierre-and-Marie-Curie University14, Université Paris-Saclay15, Massachusetts Institute of Technology16, University of Illinois at Urbana–Champaign17
TL;DR: In this article, the authors measured multihadron production in e+e− annihilation at center-of-mass energies between 2.6 and 7.8 GeV and found that the total hadronic cross section was approximately 2.7 times the cross section for the production of muon pairs at c.m.
Abstract: Measurements of multihadron production in e+e− annihilation at center-of-mass energies between 2.6 and 7.8 GeV are presented. Aside from the narrow resonances ψ(3095) and ψ(3684), the total hadronic cross section is found to be approximately 2.7 times the cross section for the production of muon pairs at c.m. energies below 3.7 GeV and 4.3 times the muon-pair cross section at c.m. energies above 5.5 GeV. Complicated structure is found at intermediate energies. Charged-particle multiplicities and inclusive momentum distributions are presented.
TL;DR: It is concluded that the enzyme-containing vesicles in these cells constitute the lysosomes and that they are distinct from other platelet organelles.
TL;DR: In this article, it was shown that phonon dispersion curves of crystals can be calculated from first principles within the local density functional formalism using atomic numbers and masses of constituent elements and crystal structures as the only input information.
Abstract: We demonstrate that by using atomic numbers and masses of constituent elements and crystal structures as the only input information, phonon dispersion curves of crystals can be calculated from first principles within the local-density-functional formalism. As shown by an exemplary calculation for the [001]-direction phonon dispersion curves of Si, the agreement with experiment is excellent. The calculation is carried out using the ab initio pseudopotential method and the Hellmann-Feynman theorem.
TL;DR: In this article, the economic worthiness of a conservation measure is expressed in terms of the cost of conserved energy, and a measure is considered economical when the cost is less than the price of the energy it replaces.
Abstract: Supply curves of conserved energy provide an accounting framework that expresses the potential for energy conservation. The economic worthiness of a conservation measure is expressed in terms of the cost of conserved energy, and a measure is considered economical when the cost of conserved energy is less than the price of the energy it replaces. A supply curve of conserved energy is independent of energy prices; however, the economical reserves of conserved energy will depend on energy prices. Double-counting of energy savings and error propagation are common problems when estimating conservation potentials, but supply curves minimize these difficulties and make their consequences predictable. The sensitivity of the cost of conserved energy is examined, as are variations in the optimal investment strategy in response to changes in inputs. Guidelines are presented for predicting the consequences of such changes. The conservation supply curve concept can be applied to peak power, water, pollution, and other markets where consumers demand a service rather than a particular good.
TL;DR: In this paper, the authors measured the signal-to-noise ratio in the Fourier transform of the image of a two-dimensional crystalline specimen, and used the results to predict the image quality under all conditions.
TL;DR: ASP as discussed by the authors is a low-power, in-field automated Seismic Processor of microearthquake network data has been designed, fabricated, and deployed for initial operation in four different field areas to monitor seismicity associated with two geothermal areas (The Geysers, California, and Cerro Prieto, Mexico), a nuclear explosion with its related collapse and aftershock sequence, and late (>1 year) activity in a major aftershock series (Livermore, California).
Abstract: ASP, a low-power, in-field Automated Seismic Processor of microearthquake network data has been designed, fabricated, and deployed for initial operation in four different field areas to monitor seismicity associated with two geothermal areas (The Geysers, California, and Cerro Prieto, Mexico), a nuclear explosion with its related collapse and aftershock sequence, and late (>1 year) activity in a major aftershock series (Livermore, California). A second ASP system, with a high-speed front-end, is used in acoustic emission (1 to 20 kHz) analysis for fracture monitoring. Each of the 15 channels of ASP (configured for up to 128 channels) automatically detects, measures times and amplitudes, and computes and fits FFT9s for both the P and S waves on data sampled at 100 samples/sec. These data from each channel are then processed with a central microprocessor for hypocenter location, running b values, source parameters, event count, and P -wave polarities. The system is capable of processing a 15-station detection in approximately 40 sec, excluding printout. The initial trials have demonstrated that in-field real-time analysis of data maximizes the efficiency of microearthquake surveys allowing flexibility in experimental procedures, with a minimum of the traditional labor-intensive postprocessing. Current efforts are directed toward improving efficiency of computation and data output and in expanding software capabilities.
TL;DR: In this article, the authors developed a general procedure for calculating the net energy flux through the glazed area of a window composed of an arbitrary number of solid layers, which can have any specified solar and thermal radiation properties and enclosed spaces between solid layers can contain either air or other gases.
Abstract: To calculate the energy performance of buildings, one must know the heat-transfer characteristics of the windows as functions of environmental variables, such as temperature and wind speed. Window designs are becoming more complex in response to the need for energy conservation. In this paper, we develop a general procedure for calculating the net energy flux through the glazed area of a window composed of an arbitrary number of solid layers. These layers, which may have thin-film coatings, can have any specified solar and thermal radiation properties and enclosed spaces between solid layers can contain either air or other gases. We verified our results by comparing them with experimental measurements of heat flow using a calibrated hot-box.
TL;DR: A clinical radiotherapeutic trial using heavy charged particles in the treatment of human cancers has accrued over 400 patients since 1975, 378 of whom were treated with particles and 28 with low LET photons as control patients.
Abstract: A clinical radiotherapeutic trial using heavy charged particles in the treatment of human cancers has accrued over 400 patients since 1975, 378 of whom were treated with particles and 28 with low LET photons as control patients. Heavy charged particle radiotherapy offers the potential advantages of improved dose localization and/or enhanced biologic effect, depending on particle selected for treatment. Target sites have included selected head and neck tumors, ocular melanomata, malignant gliomata of the brain, carcinoma of the esophagus, carcinoma of the stomach, carcinoma of the pancreas, selected juxtaspinal tumors and other locally advanced, unresectable tumors. A Phase III prospective clinical trial has been started in carcinoma of the pancreas using helium ions. Phase I-II studies are underway with heavier particles such as carbon, neon and argon ions in order to prepare for prospective Phase III trials. Silicon ions are also under consideration for clinical trial. These studies are supported by the United States Department of Energy and National Institutes of Health.
TL;DR: In this article, a dc superconducting quantum interference device incorporating Josephson tunnel junctions with an inductance of about 2 pH and a capacitance per junction of about 0.3 pF was fabricated.
Abstract: We have fabricated dc superconducting quantum interference devices incorporating Josephson tunnel junctions with an inductance of about 2 pH and a capacitance per junction of about 0.3 pF. The lowest measured flux noise energy was 3.2 h/ at 1.4 K at a frequency of 202 kHz. When the 1/f noise was subtracted, the white noise energy decreased from around 3h/ at 4.2 K to below 2h/ at 1.4 K.
TL;DR: In this paper, the performance and application of an ultrahigh vacuum compatible constant-deviation double-crystal monochromator (JUMBO) in operation at SSRL is demonstrated.
TL;DR: Researchers in artificial intelligence and linguistics have pointed to the need for a realistic world model to include representations not only for snapshot descriptions of the real world, but also for histories, or the evolution of such descriptions over time.
Abstract: Numerous researchers in a handful of disciplines have been concerned, in recent years, with the special role (or roles) that time seems to play in information processing. Designers of computerized information systems have had to deal with the fact that when an information item becomes outdated, it need not be forgotten. Researchers in artificial intelligence have pointed to the need for a realistic world model to include representations not only for snapshot descriptions of the real world, but also for histories, or the evolution of such descriptions over time. Many logicians have regarded classical logic as an awkward tool for capturing the relationships and the meaning of statements involving temporal reference, and have proposed special "temporal logics" for this purpose. Finally, the analysis of tensed statements in natural language is a principal concern of researchers in linguistics.
TL;DR: It is demonstrated that no one database machine is best for executing all types of queries and it is shown that for one class of queries the degree of performance improvement achieved does not warrant use of a database machine.
Abstract: The rapid advances in the development of low-cost computer hardware have led to many proposals for the use of this hardware to improve the performance of database management systems. Usually the design proposals are quite vague about the performance of the system with respect to a given data management application. In this paper we predict the performance of several of the proposed database management machines with respect to several representative INGRES queries. The systems analyzed in this paper include associative disks, RAP, CASSM, DBC, DIRECT, and CAFS. We demonstrate that no one database machine is best for executing all types of queries. We will also show that for one class of queries the degree of performance improvement achieved does not warrant use of a database machine.
TL;DR: In this article, double differential cross sections have been measured for energetic $p, $d, $t, and $\ensuremath{\alpha}$ particles emitted in O-induced reactions on targets of A1, Zr and Au at incident energies of 140, 215, and 310 MeV.
Abstract: Double differential cross sections have been measured for energetic $p$, $d$, $t$, and $\ensuremath{\alpha}$ particles emitted in $^{16}\mathrm{O}$-induced reactions on targets of A1, Zr, and Au at incident energies of 140, 215, and 310 MeV. The energy and angular distributions are well described by isotropic emission from a moving thermal source. The extracted temperature and velocity parameters are found to vary systematically with the incident energy per nucleon above the Coulomb barrier. The observed trends cannot be explained by compound nucleus emission but instead suggest emission from a source which consists of comparable contributions from target and projectile. Alternatively, the proton energy spectra are compared with a precompound model and with a simple knockout model. The $d$, $t$, and $\ensuremath{\alpha}$-particle cross sections are also described in terms of a generalized coalescence relation which takes into account Coulomb repulsion from the target nucleus.
01 Jan 1982
TL;DR: In this article, the Fourier Transform Nuclear Quadrupole Resonance (FT-NQR) spectroscopy is used to detect pure quadrupole coupling transitions in solids.
Abstract: FT-NQR (Fourier Transform Nuclear Quadrupole Resonance) spectroscopy is one of the newer analytical tools. Although nuclear quadrupole coupling constants were first observed in atoms by Schmidt and Schuler1 in 1935 and in molecules by Kellog2 and coworkers in 1936, it was the discovery of pure quadrupole coupling transitions in solids by Dehmelt and Kruger3,4 in 1950 and 1951 that initiated the understanding of the NQR phenomenon as presently utilized.
TL;DR: In this article, a first-principles calculation of the phonon frequencies and mode-Gruneisen parameters of Al with the use of the atomic number and the atomic mass as the only inputs is presented.
Abstract: We report a first-principles calculation of the phonon frequencies and mode-Gr\"uneisen parameters of Al with the use of the atomic number and the atomic mass as the only inputs. The phonon frequencies are determined by calculating the total energy of the perfect crystal and that of the crystal distorted by a frozen-phonon mode. Calculated results agree very well with experimental values. The contributions to the restoring force for various phonon modes are analyzed and discussed.
TL;DR: In this paper, the growth and chemisorptive properties of monolayer films of Ag and Au deposited on both the Pt(111) and the stepped Pt(553) surfaces were studied using Auger electron spectroscopy (AES), thermal desorption spectrography (TDS), and low energy electron diffraction (LEED).