Showing papers by "Louisiana State University published in 1975"

Water escape structures in coarse-grained sediments

Abstract: Three processes of water escape characterize the consolidation of silt-, sand-and gravel-sized sediments. Seepage involves the slow upward movement of pore fluids within existing voids or rapid flow within compact and confined sediments. Liquefaction is marked by the sudden breakdown of a metastable, loosely packed grain framework, the grains becoming temporarily suspended in the pore fluid and settling rapidly through the fluid until a grain-supported structure is re-established. Fluidization occurs when the drag exerted by moving pore fluids exceeds the effective weight of the grains; the particles are lifted, the grain framework destroyed, and the sediment strength reduced to nearly zero. Diagenetic sedimentary structures formed in direct response to processes of fluid escape are here termed water escape structures. Four main types of water escape structures form during the fluidization and liquefaction of sands: (1) soft-sediment mixing bodies, (2) soft-sedimsnt intrusions, (3) consolidation laminations, and (4) soft-sediment folds. These structures represent both the direct rearrangement of sediment grains by escaping fluids and the deformation of hydroplastic, liquefied, or fluidized sediment in response to external stresses. Fundamental controls on sediment consolidation are exerted by the bulk sediment properties of grain size, packing, permeability, and strength, which together determine whether consolidation will occur and, if so the course it follows, and by external disturbances which act to trigger liquefaction and fluidization. The liquefaction and fluidization of natural sands usually accompanies the collapse of loosely packed cross-bedded deposits. This collapse is commonly initiated by water forced into the units as underlying beds, especially muds and clays, consolidate. The consolidation of subjacent units is often triggered by the rapid deposition of the sand itself, although earthquakes or other disturbances are probably influential in some instances. Water escape structures most commonly form in fine- to medium-grained sands deposited at high instantaneous and mean sedimentation rates; they are particularly abundant in cross-laminated deposits but rare in units deposited under upper flow regime plane bed conditions. Their development is favoured by upward decreasing permeability within sedimentation units such as normally graded turbidites. They are especially common in sequences made up of alternating fine-(clay and mud) and coarse-grained (sand) units such as deep-sea flysch prodelta, and, to a lesser extent, fluvial point bar, levee, and proximal overbank deposits.

Gravitational two-body problem with arbitrary masses, spins, and quadrupole moments

Abstract: We find the precession of the spin and the precession of the orbit for the two-body problem in general relativity with arbitrary masses, spins, and quadrupole moments. One notable result which emerges is that, in the case of arbitrary masses ${m}_{1}$ and ${m}_{2}$, the spin-orbit contribution to the spin precession of body 1 is a factor $\frac{({m}_{2}+\frac{\ensuremath{\mu}}{3})}{({m}_{1}+{m}_{2})}$ times what it would be for a test body moving in the field of a fixed central mass (${m}_{1}+{m}_{2}$). Here $\ensuremath{\mu}$ denotes the reduced mass $\frac{{m}_{1}{m}_{2}}{({m}_{1}+{m}_{2})}$. This contrasts with the result of Robertson for the periastron precession where the corresponding factor is unity. These results may be of interest for binary neutron stars and, in particular, for binary pulsars such as PSR 1913+16.

Effect of alternate aerobic and anaerobic conditions on redox potential, organic matter decomposition and nitrogen loss in a flooded soil

Abstract: The effect of several cycles of varying length of alternate aerobic and anaerobic conditions on redox potential, organic matter decomposition and loss of added and native nitrogen was investigated under laboratory conditions in flooded soil incubated for 128 days. Redox potential decreased rapidly when air was replaced with argon for the short-time cycles, but decreased more slowly where the aerobic period was long enough to permit build-up of nitrate. The minimum redox potential reached during the anaerobic period was generally lower for the longer cycles, but in all cases was low enough for denitrification to occur. Rate of decomposition of organic matter was faster in the treatments with a greater number of alternate aerobic and anaerobic periods. Total N (native and applied) losses as high as 24.3 per cent occurred in the treatment with the maximum number of cycles and with alternate aerobic and anaerobic periods of 2 and 2 days. Increasing the durations of the aerobic-anaerobic periods decreased the loss of N. A maximum loss of 63.0 per cent of applied 15NH4-N resulted from the shortest (2 and 2 day) aerobic and anaerobic incubation. For soil undergoing frequent changes in aeration status the only labelled N that remained at the end of incubation was found in the organic fraction. Loss of N may have been even greater if labelled inorganic N had not been immobilized by microorganisms decomposing the added rice straw. The greater loss of N resulting from the 2 and 2 day aerobic-anaerobic incubation shows that, in soils where the redox potential falls low enough for denitrification to occur, increasing the frequency of changing from aerobic to anaerobic conditions will increase the loss of N.

The Social Challenge to Business

Abstract: This article presents a review of the book “The Social Challenge to Business,” by Robert W. Ackerman.

Halogenated hydrocarbons in New Orleans drinking water and blood plasma.

Abstract: Volatile organics from New Orleans drinking water and pooled plasma were collected on a solid phenyl ether polymer and analyzed by gas chromatographic and mass spectrometric techniques. Thirteen halogenated hydrocarbons were identified in the drinking water. Five halogenated compounds were found in the plasma. Tetrachloroethylene and carbon tetrachloride were found in both the plasma and the drinking water. Considerable variation in the relative concentrations of the halogenated hydrocarbons was noted from day to day in the drinking water.

A specific complement-fixation test for human hepatitis a employing CR326 virus antigen. Diagnosis and epidemiology.

Abstract: A specific diagnostic complement-fixation test for hepatitis A antibody in human serum was described employing livers of marmosets infected with CR326 strain human hepatitis A virus Persons with hepatitis A, but not hepatitis B, developed hepatitis A CF antibody shortly after the onset of illness and this persisted thereafter Good agreement was noted in the development of CF and neutralizing antibodies in hepatitis A cases Hepatitis A was shown to occur in a person with hepatitis B antigenemia and hepatitis B occurred in persons with hepatitis A antibody Most persons with hepatitis A who were tested, but none of those with hepatitis B, developed increased anticomplementary activity in their sera at the time of onset of illness At least one patient with hepatitis A developed antibody against normal liver that persisted The possible inplications of this in relation to pathogenesis and to non-specific diagnostic tests in hepatitis were discussed A limited epidemiologic study of a family outbreak of hepatitis in Costa Rica and of a group of young adults in our epidemic country acquire their infections at an early age and are immune thereafter; persons in areas of relatively low incidence may proceed into adulthood without experience with hepatitis A The CF test should provide an excellent tool for diagnosis and for epidemiologic investigation of hepatitis A and should be of considerable value to detect hepatitis A virus in attempts to propagate the virus in cell culture

Spin-orbit coupling, Fermi surface, and optical conductivity of ferromagnetic iron

Abstract: A previous self-consistent linear-combination-of-atomic-orbitals calculation of energy bands in iron has been extended through the inclusion of spin-orbit coupling. The exchange interaction is incorporated according to the $X\ensuremath{\alpha}$ method. The Fermi surface is described in detail and compared with the results of measurements of the de Haas-van Alphen effect, and of magnetoresistance anisotropy. The interband contribution to the optical-conductivity tensor was computed using matrix elements determined from wave functions including spin-orbit coupling. Both diagonal and off-diagonal elements of this tensor have been obtained.

Interactions between Encephalitozoon cuniculi and macrophages. Parasitophorous vacuole growth and the absence of lysosomal fusion.

Abstract: Encephalitozoon cuniculi grow within ever-increasing parasitophorous vacuoles (PV) in peritoneal macrophages. The PV boundary membrane conforms to a rich arrangement of blebs; similar, but free vesicles were observed within the PV space. An iron dextran-concanavalin A marker was used to express visually clustered distributions of Con A receptors on the PV boundary blebs and free vesicles; no marker was observed on other membrane surfaces within the PV. These results, combined with the observation that the PV grows while the host cytoplasm decreases in mass, implicate the PV boundary blebs of interiorizing into vesicles by a pinocytic mechanism.

The electronic structure of Cs2NaEuCl6

Abstract: The visible absorption spectrum and magnetic circular dichroism (MCD) spectrum have been measured for Cs2NaEuCl6 at room temperature. The absorption spectrum and Zeeman splitting have been measured at liquid helium temperature as well. The Eu3+ is in a site of six-coordinate octahedral symmetry. Transitions from the 7 F 0(A 1g ) ground state and, thermally populated 7 F 1(T 1g ) state to the 5 D 0(A 1g ), 5 D 1(T 1g ), and 5 D 2(T 2g + Eg ) states have been observed. The fourth-order crystal-field parameter (B 4) has been found to be 10–11 cm-1 at both temperatures. A rich vibrational structure was seen on the two electric diple-allowed transitions and an assignment of the observed vibrations made. At liquid helium temperature the g values of the 5 D 1(T 1g ) and 5 D 2(T 2g ) states were found to be 1·5±0·15 and 1·5±0·5, respectively.

Purchasing power parity and black-market exchange rates

Abstract: This paper develops a theory of black-market exchange rate determination as a function of the market-clearing rate, the official rate and changes in official reserve levels. The model is tested for three countries over the period 1952–1971 by using purchasing-power-parity calculations as approximations of the equilibrium rate. The results indicate that relative rates of inflation are the dominant forces influencing equilibrium exchange rates.

Food Habits, Length-Weight Relationship, Condition Factor, and Growth of Juvenile Red Drum, Sciaenops ocellata, in Louisiana

Abstract: Food habits of 568 juvenile red drum, Sciaenops ocellata (Linnaeus), ranging from 8.0 to 183.0 mm standard length, were determined during the time the fish utilized a Louisiana salt marsh as a nursery area. Potentially available food organisms were sampled during the 7-mo study. Some degree of selectivity by juvenile red drum was demonstrated, but generally the most abundant organisms of an edible size were utilized most heavily. Changes in food with increasing size can be described in three phases: 1) red drum less than 15 mm ate zooplankton; 2) between 15 mm and 75 mm the red drum ate mostly small bottom invertebrates and the young of other fish; 3) red drum larger than 75 mm ate decapods (crabs and shrimp) and fish. Some differences between day and night feeding were found. For red drum 65 to 85 mm the dominant food eaten was grass shrimp during the day, whereas at night it was fish. The length-weight relationship was log W = −7.2052 + (4.1913) (log L). The average coefficient of condition was...

Trajectories and Speeds of Wind-Driven Currents Wear the Coast

Abstract: Detailed observation of drogue movements within 800 m of a straight shoreline indicates the primary current generated by local winds to be directed within a few degrees of parallel to the shore nearly independently of wind direction. Subtle vertical structure in the onshore-offshore speed component is dependent on vertical stratification such that unstratified water produces a two-layered flow (onshore in the surface layer, offshore in the bottom layer), and moderately stratified water produces a three-layered flow (onshore in surface and bottom layers, offshore at intermediate depths). Theoretical conclusions from Jeffreys' constant eddy viscosity theory support the unstratified velocity profile and accurately predict the alongshore current speeds. Numerical solutions with a depth-dependent eddy viscosity indicate that the three-layered flow pattern is a direct result of the density gradient. Even in these shallow waters the inclusion of Coriolis effects in the theory is necessary for a complete...

Chronophysiology of Prolactin in the Lower Vertebrates

Abstract: In every instance tested, responses to prolactin in fish, frogs, lizards, birds and mammals vary markedly during the day. At certain intervals prolactin may stimulate gains in body fat stores, whereas at other intervals it may cause fat losses. Similarly, there are specific times for gonadal prosteroidogenic and antisteroidogenic activities, augmentation of body growth, inhibition of amphibian metamorphosis, pigeon cropsac stimulation, induction of migratory restlessness, and the control of migratory orientation. Prolactin interacts with other hormones in several ways depending on their temporal relations. Changing relations between the daily rhythms of prolactin and the corticosteroid rhythms are thought to control the orderly and coordinated sequences of physiological and behavioral conditions during the annual cycle and in development.

anthropologist—the myth teller1

Abstract: The meaning of the anthropological movement comes from the sense of mission created out of the ethnographer's encounter with his alter, the informant. The traditional pattern of ethnographer-informant relations, in which the informant was the man of wisdom and the ethnographer his most briliant student, was permeated with a sense of rightness expressed in the morality of cultural relativism. Changes in the personnel who become the ethnographer and the informant and changes in their home societies have created a new reality against which the traditional pattern has collapsed. Out of the collapse arises the reaffirmation of the anthropologist as teller of the human myth.

Simple model and wave function for atoms in intense magnetic fields

Abstract: The structure of heavy atoms in strong magnetic fields of the order of ${10}^{12}$ G, such as are generally presumed to be present on pulsars, has been previously described in terms of a magnetic Thomas-Fermi (TF) model, suitably adapted from the normal TF model. We present here a model which is analogous to the well-known screening-theory approach for ordinary, "laboratory" atoms---the electrons occupy various orbits with a transverse dimension characterized by the radius of magnetic cyclotron orbits and an over-all dimension characterized by Bohr orbits. Not only does this model give results similar to, though quantitatively more reliable than, the magnetic TF model, but it provides more insight into the structure of atoms in strong magnetic fields. For instance, the number of electrons in the $n\mathrm{th}$ shell is seen to be proportional to ${n}^{4}$ instead of the usual $2{n}^{2}$ in the laboratory situation. This accounts for the tighter binding of such atoms, a result already derived in the magnetic TF model, but also goes further in suggesting a new kind of shell structure and a new Periodic Table for atoms in strong magnetic fields. Quantum mechanically, our model is based on energy minimization with a simple analytical wave function and this represents the first time a simple wave function has been suggested for heavy atoms in strong magnetic fields. The wave function consists of an antisymmetrized product of single-particle orbitals, each of which is a product of an ordinary hydrogenic radial function and a magnetic Landau orbital so that both the spherical Coulombic and cylindrical magnetic symmetry of the problem are taken into account. However, in analogy with Bohr theory, we motivate and discuss many of the results without explicit use of this wave function. An approximate electron density function is trivially established which is itself physically more reasonable than the corresponding magnetic TF function. Further, our model is valid over a broader range of magnetic-field values and its variational-bound character allows for both successive improvements in its predictions and for a knowledge of the sign of the error in the energy estimate. Useful scaling laws are presented so that, starting from the knowledge of the ground-state energy for some $Z$ and $B$, the energy for other combinations of $Z$ and $B$ can be estimated. A second major result of this paper is that the single-particle wave function that arises during the course of the development of the many-electron wave function is of interest in itself, combining as it does aspects of both spherical and cylindrical symmetry. This simple wave function seems to describe well the ground state of the hydrogen atom at all values of the magnetic field.

Effect of protein concentration in the diet on blood composition and productivity of lactating Holstein cows under thermal stress

Abstract: An experiment was designed to assess the effect of thermal stress and protein value of the diet on the productivity and some of the blood organic constituents of lactating Holstein cows. Two groups of eight animals each were used in 2 × 2 Latin-square designs with two experimental diets. The percentage of crude protein in the diets was 14.3 and 20.8 %.Rectal temperature and respiration rate were recorded twice weekly and jugular blood samples were collected at weekly intervals for analysis. Daily feed intake, refusals and milk production per cow were recorded. Representative samples of morning and afternoon milk were taken three times a week for chemical analysis.Data on respiration rate and rectal temperature suggested that both groups of animals were under thermal stress. However, significantly lower values were found by increasing the protein level of the diet. The higher level of protein significantly increased total milk production, 4 % fat-corrected milk (4 % FCM), total solids, solidsnot-fat, protein percentage and yield, casein and non-protein-nitrogen in milk. The increase in milk production and 4 % FCM was found to be associated with the increase in total feed and total-digestible-nutrients intake but not with crude-protein intake. Protein levels in the diet had no effect on fat percentage and yield nor on whey protein.The correlation coefficients between respiration rate and rectal temperature with some of the blood organic constituents suggested an inverse relation between thermal stress and the blood organic constituents. The higher level of protein in the diet significantly increased haemoglobin levels but had no effect on oxyhaemoglobin, haemoglobin:oxyhaemoglobin ratio and haematocrit value. Total serum protein was not affected by thermal stress or by the protein value of the diet. Increasing protein levels in the diet increased albumin but decreased the globulin fraction of serum protein. Plasma glucose and non-protein nitrogen were increased by increasing the protein in the diet.

Microbial Indicators of Oil-Rich Salt Marsh Sediments

Abstract: Selected microbial parameters were monitored in sediments from a pristine and an oil-field salt marsh. Although numbers of hydrocarbonoclastic bacteria and fungi were significantly greater in the oil field, the values did not show a strong correlation with levels of hydrocarbons (r = 0.43 and r = 0.49, respectively). However, a high correlation was noted between ratios of hydrocarbonoclastic and total aerobic heterotrophic bacteria and levels of hydrocarbons as well as the relative concentration of hydrocarbons (ratio of hydrocarbons to chloroform extractables) (r = 0.87 and r = 0.77, respectively). Data suggest that this first ratio is a more valid microbial indicator of hydrocarbon abundance than other factors examined. Significant differences in the ratio of pigmented to total colony-forming units, the ratio of different to total colony-forming units, and the diversity index were noted between the natural and oil-field marsh. It is suggested that the presence of hydrocarbons alters the relative abundance of the most predominant aerobic heterotrophic bacteria.