Showing papers by "Louisiana State University published in 1984"
TL;DR: In this article, a two-part review of distribution functions in physics is presented, the first part dealing with fundamentals and the second part with applications, focusing on the so-called P distribution and generalized P distribution.
2,421 citations
TL;DR: A series of hypotheses is presented about the relation of national energy use to national economic activity (both time series and cross-sectional) which offer a different perspective from standard economics for the assessment of historical and current economic events.
Abstract: A series of hypotheses is presented about the relation of national energy use to national economic activity (both time series and cross-sectional) which offer a different perspective from standard economics for the assessment of historical and current economic events. The analysis incorporates nearly 100 years of time series data and 3 years of cross-sectional data on 87 sectors of the United States economy. Gross national product, labor productivity, and price levels are all correlated closely with various aspects of energy use, and these correlations are improved when corrections are made for energy quality. A large portion of the apparent increase in U.S. energy efficiency has been due to our ability to expand the relative use of high-quality fuels such as petroleum and electricity, and also to relative shifts in fuel use between sectors of the economy. The concept of energy return on investment is introduced as a major driving force in our economy, and data are provided which show a marked decline in energy return on investment for all our principal fuels in recent decades. Future economic growth will depend largely on the net energy yield of alternative fuel sources, and some standard economic models may need to be modified to account for the biophysical constraints on human economic activity.
781 citations
TL;DR: The limited observations available support the hypothesis that salt marshes offer significant escape from mortality due to predation, but there have been yet few experimental tests of this hypothesis.
Abstract: Salt marshes are widely believed to serve as nurseries for many fishes and crustaceans of fishery value as a result of the high production of vascular plant detritus and the protection from predation offered by shallow, spatially complex habitats. Comparisons of the yields of species which reside in salt marsh habitats during critical life history stages (such as penaeid shrimp) with the area of such habitats and their greater densities in flooded marshes and associated tidal creeks support the premise that marshes enhance the yield of such species. A range of evidence, including the amount of detrital export from marshes, the poor nutritive value of vascular plant detritus, and natural diets, casts doubt on the notion that production of fishery species is based on the direct consumption of marsh grass detritus or predominantly on food chains based on this detritus. Vascular plants and associated algae may, however, contribute to the production of prey species. The limited observations available support the hypothesis that salt marshes offer significant escape from mortality due to predation, but there have been yet few experimental tests of this hypothesis. Knowledge of relative importance of the food and refuge functions in support of living resources is of practical value in marsh and fisheries management. Better understanding of these roles is important to the effective evaluation of the effects of coastal habitat modifications on fisheries resources and design of alterations to minimize the losses of these values.
653 citations
01 Jan 1984
TL;DR: In this paper, the authors consider ways to combine sets of data for the purpose of estimation that may violate a basic assumption of the linear regression model, and they focus on models with parameters that vary in some systematic and/or random way across partitions of the sample data, even from observation to observation.
Abstract: In this and the following chapter we consider ways to combine sets of data for the purpose of estimation that may violate a basic assumption of the linear regression model. Specifically, we will study cases when it cannot be assumed that the structural parameters are identical for all observations in a sample of data. Frequently these problems occur when a data set consists of series of observations over time on cross-sectional units. Many of the topics discussed in this chapter can or do apply directly to the pooling of time series and cross-sectional data, but the primary discussion of that topic is contained in Chapter 15. In this chapter we focus on models with parameters that vary in some systematic and/or random way across partitions of the sample data, even from observation to observation.
608 citations
TL;DR: In this paper, a critical review on nitrogen transformations functioning in flooded soils and sediments, and their role in nitrogen loss from the system is presented. But, the review is limited to two processes: ammonification and denitrification.
Abstract: This paper presents a critical review on nitrogen (N) transformations functioning in flooded soils and sediments, and their role in N loss from the system. Nitrogen transformations reviewed include (1) ammonification (organic ? ammonium N) (2) nitrification (ammonium ? nitrate), (3) ammonia volatilization (ammonium N ? NH3), (4) denitrification (nitrate ? gaseous products N2O and N2). Transport processes reviewed were ammonium and nitrate diffusion. Inorganic N in flooded soils and sediments and waters is converted to gaseous forms by two processes, i.e., (1) nitrification‐denitrification; and (2) NH3 volatilization. The former process seems to be more predominantly involved in the ammonium N loss from the sediments, whereas the latter process occurs under specialized conditions, mainly in the overlying waters. The processes involved in converting organic N to gaseous end products include ammonification of organic N to ammonium N, upward diffusion of ammonium N into the aerobic soil layer, oxidation of am...
505 citations
TL;DR: In this paper, the casuality between GNP and energy consumption was examined by using updated US data for the period 1947-1979, and the causal relationship between energy consumption and employment was investigated.
440 citations
TL;DR: Seasonal sedimentation, measured with the aid of artificial marker horizons, was markedly different in deteriorating as compared with stable marshes in the Mississippi River deltaic plain, indicating the importance of considering accretion relative to submergence.
Abstract: Seasonal sedimentation, measured with the aid of artificial marker horizons, was markedly different in deteriorating as compared with stable marshes in the Mississippi River deltaic plain. Deteriorating marshes receive most sediment during storm events, whereas stable marshes receive substantial amounts of sediments during the spring river flood. The deteriorating marshes are accreting at a faster rate (1.5 centimeters per year at streamside, 0.9 centimeter per year at inland areas) than the stable marshes (1.3 centimeters per year at streamside, 0.6 centimeter per year at inland areas). However, relative to local apparent sea-level rise as measured by tide gauges in each area, the deteriorating marshes are not maintaining their intertidal elevation as well as the stable marshes. These results indicate the importance of considering accretion relative to submergence.
380 citations
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TL;DR: The recognition of a child with sporadic aniridia should alert physicians to the increased risk of development of Wilms' tumor.
375 citations
01 Mar 1984-Graphical Models \/graphical Models and Image Processing \/computer Vision, Graphics, and Image Processing
TL;DR: A study aimed at segmenting a high-resolution black and white image of Sunnyvale, California, shows that the proposed procedure should be useful for land use classifications as well as other problems.
Abstract: A study aimed at segmenting a high-resolution black and white image of Sunnyvale, California, is described. In this study regions were classified as belonging to any one of nine classes: residential, commercial/industrial, mobile home, water, dry land, runway/taxiway, aircraft parking, multilane highway, and vehicle parking. The classes were selected so that they directly relate to the Defense Mapping Agency's Mapping, Charting and Geodesy tangible features. To attack the problem a statistical segmentation procedure was devised. The primitive operators used to drive the segmentation are texture measures derived from cooccurrence matrices. The segmentation procedure considers three kinds of regions at each level of the segmentation: uniform, boundary, and unspecified. At every level the procedure differentiates uniform regions from boundary and unspecified regions. In the assigns a class label to the uniform regions. The boundary and unspecified regions are split to form higher level regions. The methodologies involved are mathematically developed as a series of hypothesis tests. While only a one-level segmentation was performed studies are described which show the capabilities of each of these hypothesis tests. In particular an 83% correct classification was obtained in testing the labeling procedure. These studies indicate that the proposed procedure should be useful for land use classifications as well as other problems.
366 citations
TL;DR: The coupling of spawning to natural oceanographic transport systems for eggs and larvae is advantageous to a species as long as those systems operate normally, as well as the details of such coupling, remain poorly understood.
Abstract: Oceanic or coastal spawning grounds of fish are often distant from nursery areas. Fish larvae require appropriate currents and sufficient and suitable food during transit to reach the nursery area at the proper time, size, and condition. Meteorologic and oceanographic factors influence food availability and transport direction and time. Annual variation in these controlling factors could affect recruitment success. Certain generalizations can be made that apply to marine and estuarine systems. Reproduction occurs in a selected portion of the species' total range. Spawning often takes place close to gyral, upwelling, or other directional circulations that frequently are associated with major current systems. The coupling of spawning to natural oceanographic transport systems for eggs and larvae is advantageous to a species as long as those systems operate normally. The details of such coupling, and the consequences for eggs and larvae of deviations from usual transport mechanisms, remain poorly un...
299 citations
TL;DR: These findings suggest that in many neuronal systems axons do not invade unknown territories during evolutionary or ontogenetic development but follow in their ancestors' paths to their ancestral targets; if the connection is later lost, it reflects the specialization of the circuitry.
Abstract: Recent studies on neural pathways in a broad spectrum of vertebrates suggest that, in addition to migration and an increase in the number of certain select neurons, a significant aspect of neural evolution is a “parcellation” (segregation-isolation) process that involves the loss of selected connections by the new aggregates. A similar process occurs during ontogenetic development. These findings suggest that in many neuronal systems axons do not invade unknown territories during evolutionary or ontogenetic development but follow in their ancestors' paths to their ancestral targets; if the connection is later lost, it reflects the specialization of the circuitry.The pattern of interspecific variability suggests (1) that overlap of circuits is a more common feature in primitive (generalized) than in specialized brain organizations and (2) that most projections, such as the retinal, thalamotelencephalic, corticotectal, and tectal efferent ones, were bilateral in the primitive condition. Specialization of these systems in some vertebrate groups has involved the selective loss of connections, resulting in greater isolation of functions. The parcellation process may also play an important role in cell diversification.The parcellation process as described here is thought to be one of several underlying mechanisms of evolutionary and ontogenetic differentiation.
TL;DR: In this article, a delta-front fjord landslide has been extensively studied using side-scan sonar, subbottom profiler, piston coring, and submersible observations.
Abstract: An example of a recently active delta-front fjord landslide has been extensively studied using side-scan sonar, subbottom profiler, piston coring, and submersible observations. The resulting sea-floor morphology and sediments have many characteristics similar to terrestrial debris flows. Analysis of cores, including physical properties and X-ray radiographs, is correlated with survey data to interpret the debris flow deformational processes and to categorize the debris flow sediments. Deformational mechanisms include delta-front sliding, downslope loading and mixing, translational shearing and remolding, and distal-lobe block gliding over weak, high-water-content fjord bottom sediments. A major part of the debris flow apparently involves remolding and deformation of fjord bottom sediments. These mechanisms result in distinctive sediment properties and structures. The data and interpretations provide a basis for comparison with other marine sedimentary sequences where slope instability processes are suspected.
Journal Article•
TL;DR: In an epidemiologic study of 2982 bladder carcinoma patients and 5782 population controls from 10 geographic areas of the United States, the role of urinary tract infection and inflammation in the etiology of this neoplasm was evaluated.
Abstract: In an epidemiologic study of 2982 bladder carcinoma patients and 5782 population controls from 10 geographic areas of the United States, the role of urinary tract infection and inflammation in the etiology of this neoplasm was evaluated. A history of urinary tract infection significantly elevated the risk of bladder cancer, particularly in individuals who reported three or more infections (relative risk (RR) = 2.0). Significantly increased bladder cancer risk was also found for bladder stones (RR = 1.8), while kidney stones showed no relation. A history of three or more urinary tract infections was strongly related to squamous cell carcinoma in particular (RR = 4.8).
TL;DR: In this paper, a Quantitative and Qualitative Review of Graphic Organizer Research is presented, with a focus on the use of graphic organizers in the context of educational research, and a review of the most relevant works.
Abstract: (1984). A Quantitative and Qualitative Review of Graphic Organizer Research. The Journal of Educational Research: Vol. 78, No. 1, pp. 11-17.
Book•
01 May 1984TL;DR: The specificity of enzymes and their ability to catalyze reactions of substrates at low concentrations is of great use in chemical analysis and has been used for analytical purposes for a long time.
Abstract: Although soluble enzymes can be used as excellent reagents for the analysis of inorganic and organic compounds, they face a serious challenge when attempts are made to utilize them in complex matrices, like blood or crude water. Problems center about the effect of activators, inhibitors, other substrates, pH, and temperature on the soluble enzyme. However, upon immobilization most of these effects can be eliminated or minimized. For example, an enzyme with a narrow pH range of 4–6 can be transformed upon insolubilization to a more viable reagent with a broad pH range of 4–10. Also, following immobilization the enzymes are much more stable; they can be heated to 37, 40 or 50°C, with little loss of activity; and the activity persists after several thousand analysis are performed. However, the biggest advantage, analytically speaking, of immobilization, is that the insolubilized reagent becomes a much more selective reagent. No longer do many activators and inhibitors have an effect; only the most powerful can actually attack the enzyme.
TL;DR: The mediation of opiate reinforcement through interactions with opiate receptors in brain regions outside the ventral tegmental area is suggested, questioning the current dopamine hypothesis for the initiation of these reinforcement processes.
Abstract: Microinfusions of the endogenous opiate neurohumor, methionine enkephalin, into the nucleus accumbens initiated a reinforcing stimulus in a dose-related manner. The reinforcing nature of this intracranial self-administration was evaluated with intermittent schedules of reinforcement and a two-lever discrimination procedure. Opiate receptors are likely responsible for the initiation of this reinforcing stimulus since naloxone effectively blocked self-administration. These data suggest the mediation of opiate reinforcement through interactions with opiate receptors in brain regions outside the ventral tegmental area, questioning the current dopamine hypothesis for the initiation of these reinforcement processes.
TL;DR: In this article, the influence of teacher time involvement, intervention type, and behavior problem severity on teachers' judgments pertaining to the acceptability of behavioral interventions was explored, which revealed that amount of time involvement affected the judgments of intervention acceptability significantly.
TL;DR: In this article, the authors investigated teachers' acceptability for both positive and reductive interventions and found that less complex or time-consuming interventions were more acceptable for positive than reductive treatments.
TL;DR: Results indicate a lower fluorescein concentration and a shorter duration of fluorescence in the absence of either NLO or eyelid closure, which seem to be safe, simple, and effective procedures that could minimize dosage requirements, as well as side effects.
Abstract: • Nasolacrimal occlusion (NLO) and eyelid closure are simple techniques that not only increase the ocular bioavailability of topically applied ocular drugs but also reduce the probability of adverse systemic effects. Each serves to improve the therapeutic index. Subsequent to the application of 0.5% timolol maleate, the effects of NLO and eyelid closure were compared with the effects of no procedures. In this experiment, systemic drug absorption in normal volunteers was reduced more than 60%. Measurements were made by radioimmunoassay of timolol in blood plasma. In addition, the diminution of fluorescein in the anterior chamber was observed for three hours following direct application to the lower cul-de-sac. Results indicate a lower fluorescein concentration and a shorter duration of fluorescence in the absence of either experimental technique. Both NLO and eyelid closure seem to be safe, simple, and effective procedures that could minimize dosage requirements, as well as side effects.
TL;DR: The authors found that immediate reinforcement is preferred to delayed reinforcement with amount of reinforcement held constant, and a large reinforcer was preferred to a small reinforcer when both were obtainable immediately.
TL;DR: A mild inflammatory response was seen at the implant sites with both particle shapes; however, inflammation resolved at a faster rate in the sites implanted with round hydroxylapatite particles.
TL;DR: In this article, it was shown that the Enewetak dolomite precipitated from cold, deep ocean water (undersaturated with respect to calcite) at a burial depth of more than 900 m.
Abstract: Dolomite is present 1,250–1,400 m below sea level in Eocene strata of Enewetak Atoll. Petrographically, the deep Enewetak dolomite postdates brittle compaction of rigid grains in the host Eocene strata. The 87 Sr/ 86 Sr ratio of these dolomites (0.70865–0.70901) indicates that they formed at one or more times between the middle Miocene and the present. Since the top of the lower Miocene is more than 900 m above the deep dolomitic interval, the dolomite must have formed at a minimum burial depth of 900 m. Stable-oxygen-isotope determinations suggest dolomite precipitation from cold marine water. Lower Miocene and Eocene carbonate strata on the atoll are apparently in open communication with cold, modern ocean water, suggesting that those same strata were in open communication with ocean water during dolomitization. At a depth of about 1,000 m, modern Pacific Ocean water becomes undersaturated with respect to calcite but is still supersaturated with respect to dolomite. Therefore, it is proposed that the deep Enewetak dolomite precipitated from cold, deep ocean water (undersaturated with respect to calcite) at a burial depth of more than 900 m.
TL;DR: The basic physiological processes active in voluntary and reflexive movement are reviewed and analyzed in light of recent data and presented as a limb joint control system including upper, lower, perceptive, and Reflexive hierarchical closed-loop regulators emphasizing the role of various feedback modalities.
Abstract: The basic physiological processes active in voluntary and reflexive movement are reviewed and analyzed in light of recent data. The individual and interactive actions of such processes (i.e., rate, recruitment, synergy, feedbacks) are integrated and presented as a limb joint control system including upper, lower, perceptive, and reflexive hierarchical closed-loop regulators emphasizing the role of various feedback modalities.
Journal Article•
TL;DR: There was a difference in the number and severity of complications between trabeculectomy and NPT, and Postoperative flat anterior chamber, uveitis, hyphema, vitreous loss, and choroidal detachment occurred more frequently after trabECUlectomy.
Abstract: In a retrospective study we compared the efficacy and safety of trabeculectomy and nonpenetrating trabeculectomy (NPT). In the latter procedure under a thin scleral flap, juxtacanalicular trabecular meshwork with Schlemm's canal is excised leaving the innermost trabecular meshwork behind. Trabeculectomy was performed on 86 eyes (66 blacks, 20 whites), whereas 71 eyes underwent NPT (44 blacks, 27 whites). The mean follow-up period was 1.7 years. Postoperatively at one year, trabeculectomy controlled 70.3% of patients with no or topical antiglaucoma medication, whereas 83.7% of NPT patients were similarly controlled. There was a difference in the number and severity of complications between trabeculectomy and NPT. Postoperative flat anterior chamber, uveitis, hyphema, vitreous loss, and choroidal detachment occurred more frequently after trabeculectomy.
TL;DR: The hypothesis that exercise recovery at a combination of intensities is superior to a recovery involving continuous submaximal exercise in lowering blood La following maximal work is not supported.
Abstract: Numerous studies have reported that following intense exercise the rate of blood lactate (La) disappearance is greater during continuous aerobic work than during passive recovery. Recent work indicates that a combination of high- and low-intensity work may be optimal in reducing blood La. We tested this hypothesis by measuring the changes in blood La levels following maximal exercise during four different recovery patterns. Immediately following 50 S of maximal work, subjects (n = 7) performed one of the following recovery treatments for 40 min: 1) passive recovery (PR); 2) cycling at 35% maximal O2 uptake (VO2 max) (35% R); 3) cycling at 65% VO2 max (65% R); 4) cycling at 65% for 7 min followed by cycling at 35% for 33 min (CR). The treatment order was counterbalanced with each subject performing all treatments. Serial blood samples were obtained throughout recovery treatments and analyzed for La. The rate of blood La disappearance was significantly greater (P less than 0.05) in both the 35% R and CR when compared with either the 65% R or PR. No significant difference (P greater than 0.05) existed in the rate of blood La disappearance between the 35% R and CR. These data do not support the hypothesis that exercise recovery at a combination of intensities is superior to a recovery involving continuous submaximal exercise in lowering blood La following maximal work.
TL;DR: In this article, the benefits of providing knowledge of results (KR) in addition to goal setting in a strategy to improve occupational safety in a farm machinery manufacturing firm were demonstrated, and an analy...
Abstract: This study demonstrated the benefits of providing knowledge of results (KR) in addition to goal setting in a strategy to improve occupational safety in a farm machinery manufacturing firm. An analy...
TL;DR: In this article, a study of the East Frisian islands has shown that the plan form of these islands can be explained by processes of inlet sediment bypassing, and the location where the swash bars attach to the beach is controlled by the amount of overlap of the ebb-tidal delta along the downdrift inlet shoreline.
TL;DR: The authors evaluated the extent to which teacher evaluations of intervention acceptability varied as a function of the type of language used to describe the intervention and found that the pragmatic description was significantly more acceptable than either the behavioral or humanistic descriptions, and all interventions were rated more acceptable when applied to a severe case.