Showing papers by "Florida State University published in 1979"

Determination of the sedimentary microbial biomass by extractible lipid phosphate.

Abstract: The measurement of lipid phosphate is proposed as an indicator of microbial biomass in marine and estuarine sediments. This relatively simple assay can be performed on fresh, frozen or frozen-lyophilized sediment samples with chloroform methanol extraction and subsequent phosphate determination. The sedimentary lipid phosphate recovery correlates with the extractible ATP and the rate of DNA synthesis. Pulse-chase experiments show active metabolism of the sedimentary phospholipids. The recovery of added 14C-labeled bacterial lipids from sediments is quantitative. Replicate analyses from a single sediment sample gave a standard deviation of 11%. The lipid extract can be fractionated by relatively simple procedures and the plasmalogen, diacyl phospholipid, phosphonolipid and non-hydrolyzable phospholipid content determined. The relative fatty acid composition can be readily determined by gas-liquid chromatography. The lipid composition can be used to define the microbial community structure. For example, the absence of polyenoic fatty acids indicates minimal contamination with benthic micro-eukaryotes. Therefore the high content of plasmalogen phospholipids in these sediments suggests that the anaerobic prokaryotic Clostridia are found in the aerobic sedimentary horizon. This would require anaerobic microhabitats in the aerated zones.

Neurogenesis and neuron regeneration in the olfactory system of mammals. I. Morphological aspects of differentiation and structural organization of the olfactory sensory neurons

Abstract: The neurogenetic process leading to the formation of primary sensory neurons persists into adult life in the olfactory epithelium of mammals. The morphological stages of maturation and ageing of this exceptional neuron have been described both at light and electron microscopical levels. For descriptive purposes the neural elements have been classified as: (1) basal cells proper, (2) globose basal cells, and (3) neurons. Intermediate stages, however, have been identified. Autoradiographic observations complement the morphological studies and provide a time sequence of the morphological stages leading to the mature neurons. A typical columnar arrangement of the sensory neurons has been described. Furthermore, active and quiescent zones have been recognized in the neuroepithelium. In the active zones the neurogenetic process is vigorous, and the zones are characterized by the presence of immature elements. However, in the quiescent zones there exists a population of mature elements while immature neurons are sparse.

Neurogenesis and neuron regeneration in the olfactory system of mammals. II. Degeneration and reconstitution of the olfactory sensory neurons after axotomy.

Abstract: This report describes the retrograde degeneration affecting olfactory sensory neurons of rats after severance of their axons and illustrates the reconstitution of new neurons originating from stem cells located at the base of the olfactory neuroepithelium. Degeneration of the mature, axotomized neurons, signalled by an increased electron density of their cytoplasmic matrix and by the appearance of lipofuscin-like granules, can be detected in the neuroepithelium as early as 24 h after surgery and becomes conspicuous between the second and the third day. Degenerating neurons can be observed in decreasing number up to the tenth post-operative day. They are removed by macrophages which invade the epithelium. The reconstitution of new neurons begins to occur after eight days, when the stem cells undergo vigorous mitotic activity and differentiate into neurons. The morphology of the reconstituted neurons has been described in detail at different stages of their maturation. After 30 days, the olfactory epithelium appears similar to controls. On the basis of both morphological (in rats) and autoradiographic ( in mice) observations, the basal cells have been recognized as stem cells of the olfactory neurons.

Large-Scale Aspects of Deep Convective Activity over the GATE Area

Abstract: Using digital IR data obtained by SMS I satellite, the large-scale behavior of convective activity was investigated over the tropical Atlantic within the GATE area. Spectral analysis has revealed the existence of two remarkable periodicities which show good association with the large-scale atmospheric field, namely, a 4-5 day mode and a diurnal mode. The area of the enhanced convection associated with the 4-5 day mode moves westward from Africa through the tropical Atlantic. Its mean phase speed turned out to be about 7° day-1 and the mean wavelength about 30° in longitude. The vertical structure of the corresponding disturbance, was investigated by the time-composite technique applied to upper air data over the GATE A/B area. The result shows that the enhancement of convection is associated with deep upward motion throughout the troposphere and southerly (northerly) winds in the lower (upper) troposphere. It also shows that the enhancement is accompanied by moistening in the cloud layer, while d...

Tests of community-wide character displacement against null hypotheses.

Abstract: Ecological character displacement is unusual dissimilarity among sympatric species in features such as body size or trophic morphology (Grant, 1972), which allows coexistence by causing species to use the environment in fashions so different that competitive exclusion is avoided (Brown and Wilson, 1956). Character displacement could arise either as a result of divergent natural selection of coexisting species, or by selective survival of immigrating species as a function of distinctness from species already present (Grant, 1969, 1970). But what dissimilarity among species is unusual? What sympatric differences are character displacement? Most evidence for the phenomenon has been taken from species pairs with morphological size ratios that are greater between sympatric than between allopatric populations. The classic example treated a pair of rock nuthatch species (Vaurie, 1951; Brown and Wilson, 1956), populations of which appeared more different in sympatry than in allopatry. However, Grant (1975) has pointed out that bill length varies over geographic clines in both species, and that the zone of sympatry has no discernible influence upon clinal variation of either. A literature review led Grant (1972) to conclude that most examples of ecological character displacement are equivocal. In only two instances do known morphological differences really conform to the pattern, one between two congeneric skinks (Huey and Pianka, 1974; Huey et al., 1974), and another between two species of snails (Fenchel, 1975). The role of competition in these differences is not well established. Community-wide morphological patterns among species have also been taken as evidence of character displacement. The reasoning is that the degree of size difference required to allow coexistence is the same among all contiguous pairs of species within communities. Among species ranked by size, constant ratios of 1.14, 1.2, 1.4, and 2 have been used in this vein (Hutchinson, 1959; Schoener, 1965; Emlen, 1966; Wilson, 1975; Terborgh et al., 1978). However, Hespenheide (1971, 1973) has shown that arbitrary ratios among sympatric species are not good evidence for character displacement, because relationships between the size of trophic structure (or body size) and food size vary substantially within and among taxa. A ratio that provides food separation for one set of species, for one circumstance, will not do so for another. Horn and May (1977) have also commented upon some of the pitfalls of deducing species interaction from constant ratios. Yet, the enthusiasm for character displacement, and for inferring avoidance of interspecific competition from interspecific size ratios, continues. The notion is described as a community principle in recent textbooks of ecology (Odum, 1971; Colinvaux, 1973; Collier et al., 1973; Ricklefs, 1973; Smith, 1974; Pianka, 1978), and is not infrequently given as research motivation or as a theorem in the current primary literature (although under various names [fide Hespenheide, 1973]). Our interest is with the logic of empirical studies of character displacement that involve large fractions of faunas (e.g., Lack, 1947; Hutchinson, 1959; Schoener, 1965; Grant, 1968; Abbott et al., 1977), rather than with studies of particular species pairs. These community-wide studies have uniformly concluded that there is a tendency for coexisting species to be unusually dis-

Biochemical Measurements of Microbial Mass and Activity from Environmental Samples

Abstract: Accurate measurement of the mass and activities of environmental microbial assemblies requires methods that differ from those of classical microbiology. Using the leaf-litter detrital microflora recovered after incubationin a semitropical estuary, biochemical assays of multiple components can be made which give reasonably similar estimates of microbial mass, using normalization values from bacterial monocultures. The assays involve recovery of adenosine triphosphate, the unique bacterial cell wall mucopeptide component muramic acid, the uniquely prokaryotic endogenous storage material poly-β-hydroxybutyrate, a series of exoesterase activities, and the extractable lipids, primarily the phospholipids and the glycolipids. If the sampling conditions are such that incorporation of radioisotopes into the microflora is possible, these assays become extraordinarily sensitive. If radioisotope usage can be coupled with the purification of particular lipids, it is possible to gain information on the structure and dynamics of the microbial population.

Species-specific predation on amphipod crustacea by the pinfish Lagodon rhomboides: Mediation by macrophyte standing crop

Abstract: The amphipod species consumed by Lagodon rhomboides represented only a small subset of the amphipod assemblage available at three seagrass habitats in Apalachee Bay, Florida (USA). Predatory preferences were related most closely to the microhabitat of prey species and were unrelated to amphipod abundances. Important prey species were all epifaunal types. Consumption of preferred amphipod species was non-selective at a site with sparse macrophyte cover, but selectivity increased with macrophyte biomass. The amphipod species that were preferentially selected as prey by pinfish correspond with those that have been suggested as being limited by fish predators. It was suggested that mediation of predator behavior by physical structure in seagrass meadows may play an important role in the regulation of species richness and abundances. Species-specific identification of prey is recommended for food-habit studies.

Striate cortex and visual acuity functions in the cat.

Abstract: Using a two-choice visual discrimination paradigm, thresholds for size (gratings), parallelness (parallel vs. non-parallel lines), contour alignment (vernier offset), and angularity (polygon figures) were behaviorally determined in cats before and after ablations of portions of the geniculo-cortical system. Animals with a total loss of cortical area 17, and with a loss, in some cases, of up to 90% of area 18 (with and without infringement into area 19), showed about a 30% reduction in grating acuity, a three-fold increase in parallelness and angularity thresholds, and a total loss of contour alignment ability. Control animals with ablations sparing area 17 showed no significant threshold changes. All animals were able to learn classic form discriminations postoperatively, but those with area 17-18 lesions at a somewhat slower than normal rate. Control procedures indicated that all tested discrimination capabilities did not depend on luminance differences between targets, local flux cues within the targets, or on the animals' use of residual portions of area 17 representing the peripheral visual field. Since the cat has multiple thalamo-cortical visual pathways, the results of the present study are consistent with the hypothesis that pathways parallel to the geniculo-striate system are capable of processing spatial information of considerable detail. The results also suggest, however, that the geniculo-striate system is uniquely necessary for the processing of the finest attributes of spatial contours.

Direct spectroscopic observation of singlet oxygen emission at 1268 nm excited by sensitizing dyes of biological interest in liquid solution.

Abstract: The direct observation of dye-photosensitized 1268-nm emission of the 1Δg → 3Σg transition of molecular oxygen in liquid solution at room temperature is reported. Singlet oxygen was photosensitized by UV excitation of perfluorobenzophenone in fluorocarbon solvent, by 3,4-benzpyrene and hematoporphyrin in carbon tetrachloride, and by methylene blue in water. Also reported is the development of an extremely sensitive near-infrared spectrophotometer that uses a thermoelectrically cooled lead sulfide detector, optimized optics, and a boxcar integrator as a data processor.

Ecological Significance of Fronts in the Southeastern Bering Sea

Abstract: A series of three fronts divides the continental shelf of the southeastern Bering Sea into two interfrontal zones which contain different food webs. Large stocks of birds, mammals, and pelagic fish, primarily walleye pollock, occur in the outer shelf zone between the 200 meter isobath and the middle front near the 100 meter isobath. Large stocks of benthic infauna, demersal fish, and crabs occur in the middle shelf zone between the middle front and the inner front at the 50 meter isobath. Very low cross-shelf advection and the presence of the middle front which acts as a diffusion barrier restrict large oceanic herbivores to the outer shelf zone. Large diatoms are not grazed by the small coastal herbivores which inhabit the middle shelf zone, resulting in an accumulation of phytoplankton biomass which settles to the benthos.

A statistical model of turbulence in two-dimensional mixing layers

Abstract: A statistical model of turbulence in fully developed two-dimensional incompressible turbulent mixing layers is proposed. The development of this model is largely motivated by the recent experimental observations of Brown and Roshko (1974). The model is based on the proposition that the turbulence of a fully developed two-dimensional incompressible mixing layer is in a state of quasi-equilibrium. The model is used to predict the second-order turbulence statistics of the flow including single-point turbulent Reynolds stress distribution, intensity of turbulent velocity components, rms turbulent pressure fluctuations, power spectra and two-point space-time correlation functions. It is shown that numerical results compare favorably with available experimental measurements.

The seasonal variation of atmospheric pressure on Mars as affected by the south polar cap

Abstract: The daily mean pressures at two locations on Mars, observed over 57% of a Martian year, reveal a semiannual oscillation with a peak-to-peak difference that is 26% of the mean pressure. This intrinsically Martian phenomenon is caused by exchange of CO2 between the atmosphere and the winter polar caps. Evidence is presented that the difference in pressure at the two landers varies with season and that the seasonal variation is not completely removed by hydrostatic correction for the difference in elevation. The mass CO2 sublimed from the south polar cap is estimated to be greater than or equal to 7.9 x 10 to the 12th metric tons, corresponding to a mean thickness of solid CO2 over the maximum extent of that cap of greater than or equal to 23 cm. Estimates are formed of the meridonal wind speed conveying gas out of the dissipating cap and the associated zonal geostrophic wind, both averaged over longitude. The results are approximately 2.3 m/sec and 14 m/sec, respectively.

Herbivory and predation by the mangrove tree crab Aratus pisonii.

Abstract: The mangrove tree crab (Aratus pisonii) is a key member of the arboreal arthropod community of the red mangrove (Rhizophora mangle) swamps of south Florida. Its ecological roles include primary herbivory, predation, and export of biomass and energy in the form of offspring and frass. Although the larval stage is planktonic, distribution of adults and Aratus leaf damage are patchy.

Against our will: male interruptions of females in cross‐sex conversation*

Abstract: A disturbing suggestion is sometimes made to the effect that women “ask for” discriminatory and even brutal treatment by men. In lay communities, the most blatant form of this suggestion (i.e., women invite rape) is increasingly deplored.’ However, when they are made in the context of empirical inquiry, suggestions with similar implications may go overlooked. In discussions of the initiation of simultaneous talk (cf. Zimmerman and West, 1975; West and Zimmerman, 1977) reports of males’ systematic interruptions of females often draw questions regarding women’s part in creating, sustaining or inviting men’s interruptions of their utterances. For example, I have observed females falling silent for longer and longer durations after repeated interruptions by males (Zimmerman and West, 1975: 117-124). One interpretation of this observation is that females engage in a form of silent protest against male intrusion into their turns. Another explanation I have heard offered for this finding is that females’ silence “encourages” males’ interruption. In fact, the topics women talk about, the “style” of “women’s talk,” and the extent to which they protest when men violate their conversational turnspace have all been offered as reasons for males’ interruptions of females. Male dominance in conversation might be likened to our cultural (and sometimes legal) conceptions of rape. Women are seen by some to invite rape by the clothes they wear, the “style” of “women’s walk” and, especially, for their failure to “put up a fight.”* However, the extent to which we find empirical bases for the existence of a struggle is the extent to which dominance in conversation and physical rape may both be defined as conflict situations and not willing submission.

FMRFamide, a Cardioexcitatory Neuropeptide of Molluscs: An Agent in Search of a Mission

Abstract: Aqueous extracts of molluscan ganglia have cardioexcitatory activity that is not attributable to the usual neurohumors: 5-hydroxytryptamine, acetylcholine or dopamine. Morphological, physiological and biochemical studies have suggested that this cardioexcitation is caused by a handful of unidentified neurohormones, mostly polypeptides. One of the active components of extracts of the pooled central ganglia of Macrocallista nimbosa (Bivalvia) has now been isolated, purified, characterized and synthesized. This substance, previously designated peak C, is a tetrapeptide amide: phenylalanyl-methionyl-arginyl-phenylalanine amide (Phe-Met-Arg-Phe-NH2; FMRFamide). Low concentrations of FMRFamide (threshold: 10−9–10−8M) induce rhythmical activity in isolated quiescent bivalve hearts and augment the force and frequency of contraction of those already beating. The peptide also produces contractures of non-cardiac molluscan muscles, including especially the radula protractor of the whelk, Busycon contrarium , a sensitive assay object. The effects of FMRFamide on Mercenaria mercenaria hearts appear to be mediated by adenosine 3', 5'-monophosphate (cycwic AMP). Peak C activity occurs in all species tested in all the major molluscan classes; but we do not yet know whether all Peak C';s are FMRFamide. That FMRFamide is a neurosecretory product has still to be established, and its normal physiological role in molluscs has yet to be defined. Nevertheless, we suppose that, together with other neuropeptides, FMRFamide is released into the hemolymph to provide long-term maintenance and regulation of tone, rhythmicity and excitability of visceral muscle.

Newspaper Recycling: The Effects of Rewards and Proximity of Containers

Abstract: Newspaper recycling, if widely practiced, could contribute to the conservation of natural resources and energy. Two experiments using multiple baseline designs with reversals were conducted to inve...

The Large Numbers hypothesis and the Einstein theory of gravitation

Abstract: A study of the relations between large dimensionless numbers leads one to believe that G , expressed in atomic units, varies with the epoch. The Einstein theory requires G to be constant. One can reconcile these two requirements by supposing that the Einstein theory applies with a metric that differs from the atomic metric. The theory can be developed with conservation of mass by supposing that the continual increase in the mass of the observable universe arises from a continual slowing down of the velocity of recession of the galaxies. One is led to a model of the Universe that was first proposed jointly by Einstein & de Sitter (the E.S. model). The observations of the microwave radiation fit in with this model. The static Schwarzchild metric has to be modified to fit in with the E.S. model for large r . The modification is worked out, and also the motion of planets with the new metric. It is found that there is a difference between ephemeris time and atomic time, and also that there should be an inward spiralling of the planets, referred to atomic units, superposed on the motion given by ordinary gravitational theory. These are effects that can be checked by observation, but there is no conclusive evidence up to the present.

Correlation in Polynomial Regression

Abstract: Polynomial regression of degree p in one independent variable χ is considered. Numerically large sample correlations between χα and χβ, α < β, a, β = 1, ···, p, may cause ill-conditioning in the matrix to be inverted in application of the method of least squares. These sample correlations are investigated. It is confirmed that centering of the independent variable to have zero sample mean removes nonessential ill-conditioning. If the sample values of χ are placed symmetrically about their mean, the sample correlation between χα and χβ is reduced to zero by centering when α + β is odd, but may remain large when α + β is even. Some examples and recommendations are given.

The deep-sea isopods: A biogeographic and phylogenetic overview

Abstract: Isopod crustaceans are among the most numerous and diverse macrofaunal taxa in the deep sea. In contrast to the situation in shallow water, the Asellota encompasses the majority of the deep-sea fauna. Taxa within the Asellota exhibit marked depth zonation. Its most primitive superfamily is limited to fresh water. The rest are marine, where with increasing depth the incidence of more specialized taxa increases. Within its most advanced superfamily, Janiroidea, the most primitive families are primarily restricted to shallow water, while the more specialized families dominate in the deep sea. The most notable exception is the occurrence of these specialized families in shallow water at high latitudes. On the basis of this pattern, it has been suggested that the deep-sea fauna is a result of invasion from shallow water, primarily at high latitudes. The present paper argues that, on the contrary, the specialized deep-sea families evolved in situ, and that their presence at shallow high latitudes is th...

Normal and superconducting properties of Cs x W O 3

Abstract: The resistivity, Seebeck coefficient, superconducting transition temperature, and upper critical field have been measured in Cs/sub x/WO/sub 3/ for 0.19< or =x< or =0.30. In contrast to Rb/sub x/WO/sub 3/, no temperature-dependent anomalies were observed in either the normal resistivity or the Seebeck coefficient. The superconducting transition temperature, T/sub c/, increases monotonically with decreasing x from 2 K at x = 0.30 up to 6.7 K at x=0.20, with an inflection near 0.24. The resistivity as a function of x increases monotonically with decreasing x and also has an inflection near x=0.24.

Conduction properties of the hexagonal tungsten bronze, Rb x W O 3

Abstract: Studies of the electrical transport properties---resistivity, Hall effect, and Seebeck coefficient---of the hexagonal tungsten bronze ${\mathrm{Rb}}_{x}\mathrm{W}{\mathrm{O}}_{3}$ for $0.16l~xl~0.33$ are reported for the temperature range from 1.5 to 300 K. In the normal state, these properties show temperature-dependent anomalies which suggest a phase transition with temperature. The temperature at which this transition occurs is shown to depend on the Rb concentration, exhibiting a sharp maximum near $x=0.25$. As the Rb concentration is decreased below $x=0.33$ the superconducting transition temperature first increases above the value of 1.94 K at $x=0.33$ and then decreases to less than 1 K at $x=0.24$. As the Rb concentration is lowered further a second increase in ${T}_{c}$ is observed. This behavior appears to be associated with a phase transition at a composition near $x=0.25$. The nature of neither the transition with temperature nor the transition with concentration could be precisely determined. The superconducting state shows a large temperature-independent 60\ifmmode^\circ\else\textdegree\fi{} anisotropy in ${H}_{c2}$ in the plane perpendicular to the hexagonal axis and positive curvature in the temperature dependence of ${H}_{c2}$ near ${T}_{c}$.

Chlorophyll and nitrate fine structure in the southeastern Bering Sea shelf break front

Abstract: Ocean fronts of considerable spatial extent and temporal persistence have been described for the shelf break region along the North American Atlantic coast1–3 and along the eastern Bering Sea shelf4. Intensive fishing activity in the vicinity of the shelf break front along the mid and north Atlantic coast suggests that high biological activity is associated with the front5,6. Primary productivity and chlorophyll standing crop are enhanced along the Scotian shelf break front as a consequence of vertical transport of nutrients to the photic zone7,8. Although physical data suggest that shelf break fronts persist for periods of from weeks to years, space and time scales associated with biological activity in shelf break fronts are not well known. We report here the spatial scales and fine structure of chlorophyll and nitrate distribution in near-surface waters of the shelf break front in the southeastern Bering Sea. Data collected on several cruises during an investigation of the processes and resources of the Bering Sea shelf (PROBES) allow a first order estimate of the time scales of persistence of nutrient and phytoplankton dynamics associated with the shelf break front. Properties associated with an extensive middle shelf front inshore of the shelf break front are reported elsewhere9.

Frontal systems during passage of the Martian north polar hood over the Viking Lander 2 site prior to the first 1977 dust storm

Abstract: Analysis of a 12-sol period of wind speed, wind direction, temperature, pressure, and optical depth at the Viking Lander 2 site presents the first in situ evidence of high- and low-pressure systems, complete with fronts, on the surface of Mars. The discovery of these systems in the Lander data occurred while analyzing a period during which the north polar hood was advected over the site at midday, dramatically decreasing the surface illumination and surface-to-atmospheric heat flux. This obscuration immediately preceded a global dust storm in the southern hemisphere and low latitudes of the northern hemisphere. The direct effects of the dust storm, reached 48 N, the Lander 2 latitude, later more gradually than they reached the 22 deg N latitude of Lander 1. The system responsible for the polar hood passages is a major disturbance, and it appears that radiational damping is inadequate to stop strong frontal formation. The front analyzed is characteristic of a repetitive series of systems that pass roughly every 3.3 sols. These systems are similar to those predicted by theoretical analyses and by general circulation modeling of the Martian atmosphere and those observed in laboratory experiments.