Showing papers by "San Diego State University published in 1980"

Geometry of Gravel Streams

Abstract: A rational method has been developed to predict the regime geometry of straight active gravel streams. The analytical model is based upon a resistance equation, a bed load equation, and the condition of minimum stream power for gravel streams in equilibrium. The analytical channel geometry so obtained is in general agreement with previously established relations and observations. The analytical channel width is proportional to Q 0 . 4 7 , in which Q is the bank full discharge. Except for steep slopes, the width is essentially only a function of the discharge. The analytical depth increases with the discharge but decreases with the slope. On steep slopes, the width increases rapidly with the slope. This rapid increase in width accompanied by a decrease in depth indicates braiding tendency for steep gravel streams. As the bed load approaches zero at the lower boundary, this model for active streams reduces to the threshold theory.

Algal Mat Productivity: Comparisons in a Salt Marsh

Abstract: This paper documents the role of salt marsh algal mats in the productivity of a southern California tidal wetland. The productivity of the mats, which are composed of filamentous bluegreen and green algae and diatoms, varies both temporally and spatially in relation to tidal inundation and overstory vegetation. The estimates of net primary productivity (NPP) were highest under the canopy ofJaumea carnosa (Less.) Gray (341 g C m−2 yr−1) at low elevation. Elsewhere, NPP appeared to be limited by low light (276 g C m−2 yr−1 underSpartina foliosa Trin.) and desiccation (185 g C m−2 yr−1 underBatis martima L. and 253 g C m−2 yr−1 underMonanthochloe littoralis Engelm).

Individual differences in early child phonology

Abstract: Three studies are reported that deal with individual differences among children in the use of consonants during the early period of phonological development. The findings indicated that (1) children differ in their early phonologies, yet these differences do not extend beyond certain limits, (2) the linguistic environment cannot account for a number of these phonological differences, and (3) such differences are due in part to the fact that children's use of sounds varies considerably with the lexical items being produced. Modifications in theories of child phonology are suggested in order to account for these findings.

Evidence that Auxin-induced Growth of Soybean Hypocotyls Involves Proton Excretion.

Abstract: The role of H+ excretion in auxin-induced growth of soybean hypocotyl tissues has been investigated, using tissues whose cuticle was rendered permeable to protons or buffers by scarification (scrubbing). Indoleacetic acid induces both elongation and H+ excretion after a lag of 10 to 12 minutes. Cycloheximide inhibits growth and causes the tissues to remove protons from the medium. Neutral buffers (pH 7.0) inhibit auxin-induced growth of scrubbed but not intact sections; the inhibition increases as the buffer strength is increased. Both live and frozen-thawed sections, in the absence of auxin, extend in response to exogenously supplied protons. Fusicoccin induces both elongation and H+ excretion at rates greater than does auxin. These results indicate that H+ excretion is involved in the initiation of auxin-induced elongation in soybean hypocotyl tissue.

Cranioskeletal Features in Tupaiids and Selected Eutheria as Phylogenetic Evidence

Abstract: Anyone hoping to illustrate current difficulties with mammalian systematics might well recruit the problem of tree shrew relationships as an heuristic example. Despite the numerous, and often excellent, taxonomic and comparative studies on the subject, the phyletic position of tupaiids within the Eutheria is far from satisfactorily ascertained. The relationships of these animals have been investigated through studies of a broad spectrum of morphological and biochemical evidence, but osteological features are emphasized in many published interpretations (see Luckett, this volume).

Stable Alluvial Canal Design

Abstract: The hypothesis of minimum stream power for stable alluvial channels has been used to derive a condition for alluvial channels in equilibrium. A method incorporating this condition with a flow-resistance formula and a sediment-discharge formula has been developed to compute the width, depth, and slope of stable alluvial channels for a given set of water and sediment discharges. Applying this method yields a design chart that provides the stable width and depth of alluvial canals with trapezoidal shape for a given set of water discharge, channel slope, sediment size, and side slope. Comparing data from some regime canals and small experimental canals has shown good agreement between the observed data and analytical predictions.

Visco-Elasticity of Passive Cardiac Muscle

Abstract: A quantitative mechanical description of the heart organ requires information on the mechanical behavior of its muscle in reasonable unity and completeness. In this respect, a fundamental constitutive law for soft biological tissures was proposed by Fung in 1972. This article presents evidence to show that Fung's law is a useful law to describe the mechanical behavior of heart muscle in the unstimulated (diastolic) state with sufficient generality. A visco-elastic relaxation phenomenon is studied in the isolated cardiac muscle of cat and rabbit with the purpose of constructing a mathematical model for relaxation. Experimental results show that passive relaxation behavior of heart muscle can be adequately described by a generalized standard linear solied with a continuous distribution of relaxation times. The form of the relaxation function devised permits the application of linear visco-elasticity theory to the nonlinear cardiac muscle. The relaxation model is used to predict the force-length (stress-strain) behavior of papillary muscle with reasonable accuracy.

Salt marsh productivity with natural and altered tidal circulation.

Abstract: The effects of altered tidal circulation on southern California salt marshes are investigated by comparing a well-flushed wetland and two modified wetlands which have reduced tidal flow. The Tijuana Estuary had continuous exchange of seawater but relatively low net aerial primary productivity (0.4–1.0 kg m-2yr-1) of vascular plants. Low productivity (0.6 kg m-2yr-1) was also found in the Flood Control Channel of the San Diego River, where tidal exchange was restricted to flow through a riprap dike. High productivity (1.2–2.9 kg m-2yr-1) in Los Penasquitos Lagoon was attributed to the influences of freshwater impounded behind a sand bar which blocked the mouth of the lagoon during much of the study period. It is hypothesized that elimination of tidal flow during the growing season increased primary productivity of vascular plants because freshwater runoff decreased soil salinity and because nutrients were retained within the marsh. However, we predict that sand bar obstruction can decrease productivity if below-average rainfall leads to hypersalinity of closed lagoons. Comprehensive evaluation of the effects of altered tidal circulation requires longterm study and examination of the total ecosystem.

The disappearance of plague: a continuing puzzle.

Abstract: T THE most feared disease in early modern England was plague. Before its disappearance from England in i666,2 plague had for centuries been a dreaded visitor to the larger towns and cities of the kingdom. When an epidemic broke out in a city like London, the entire tenor of life changed. Many of the better-off inhabitants fled to the country to escape infection; commerce and industry stagnated; the usually teeming streets were empty. During the great London epidemic of i665, Samuel Pepys lamented, "Lord, what a sad time it is, to see no boats upon the River-and grass grow all up and down Whitehall-court-and nobody but poor wretches in the streets."3 As if to celebrate the relentless advance of death, the bells of the parish churches rang out at each death and each burial. To contemporaries, it seemed that God was venting his wrath on a sinful mankind. In London and other great urban concentrations of Europe, the loss of life from plague was terrible. According to the Bills of Mortality, 70,594 persons died of plague in London during the epidemic of I 665-6. The actual figure was higher, because many plague deaths were mistakenly attributed to other diseases, and it has been estimated that this one epidemic claimed 8o,ooo victims, out of a total

Kinetics and mechanism of the germane decomposition

Abstract: The homogeneous gas-phase thermal decomposition kinetics of germane have been measured in a single-pulse shock tube between 950 and 1060 K at pressures around 4000 torr. The initial decomposition is GeH4 GeH2 + H2 in its pressure-dependent regime, with log k = 13.83 ± 0.78 – 50,750 ± 3570 cal/2.303RT. RRKM calculations suggest that the high-pressure Arrhenius parameters are log k GeH4(M ∞) = 15.5 – 54,300 cal/2.303RT. Extrapolations to static system pyrolysis conditions (T ∼ 600 K, P ∼ 200 torr) give homogeneous reaction rates which are much slower than those observed, hence the static system pyrolysis of germane must be predominantly heterogeneous. Shock-initiated pyrolysis reaction stoichiometry is 2 mol H2 per mole GeH4, suggesting that the subsequent decomposition of germylene is essentially quantitative. Investigations of the hydrogen product yields for pyrolysis of GeD4 in oCH3 further indicate that the germylene decomposition reaction is mainly GeH2 H2 + Ge, but that a small amount of reaction to H atoms may also occur.

Late Jurassic lizards from Como Bluff, Wyoming and their palaeobiogeographic significance

Abstract: Fossils from the late Jurassic Morrison Formation, Como Bluff, Wyoming (Tithonian, ∼140 Myr ago) show that three genera of European lizards from the later Jurassic of England and Portugal (Cteniogenys, Paramacellodus Dorsetisaurus) also inhabited North America. These specimens corroborate evidence from mammal and other terrestrial vertebrate faunal similarities that western Europe and western North America had a continuous land connection in the late Jurassic. Some of this similarity, however, is pre-Tithonian, indicating that widespread mid-Jurassic transgressive seas in Europe were no barrier to vertebrate dispersal.

Growth functions of stochastic Lindenmayer systems

Abstract: A stochastic version of the 0L systems of Lindenmayer is introduced and the growth functions of such systems are studied. Topics covered include techniques for computing such growth functions, classification of such stochastic 0L systems according to growth rate, and decidability results about various notions of growth equivalence.

Origin of trace fossils in Polish Carpathian flysch

Abstract: Fifteen features of trace fossils on flysch sandstone soles have been found useful in distinguishing between pre-depositional traces of mud-inhabiting animals and post-depositional traces of sand-dwellers. The Polish Carpathian flysch ichnofauna of 55 genera and 145 species, including 41 ichno-genera that occur at least in part on sandstone soles, is dominated both in number of taxa and number of specimens by traces of mud inhabitants, and most traces, both of mud- and sand-dwellers, were produced by infaunal deposit-feeders. Because mud was the temporally dominant substrate, the mud-dwellers were much more abundant over long periods of time, but the fauna of turbidites and similar sands may have been nearly as diverse and abundant at any given moment as the mud fauna at another. The currents depositing these sands eroded surficial layers of mud and excavated any burrow fillings in almost every case. The flysch ichnofauna differs from observed trace assemblages of modern deep-sea substrates in that the former consists almost exclusively of burrows, while surface traces dominate the latter.

The Social Role of Slang

Abstract: Slang is a common linguistic behaviour. Despite this it has been collected rather than defined and studied by linguistics. Dumas and Lighter have attempted to establish criteria for defining the concept, but commit the mistake of neglecting slang as a social psychological phenomenon. To place slang in a societal frame a variation of Giles' accommodation theory is used. The use of slang is offered as a major index and signal of alienation and solidarity, remarkable in that the same locution can signal both in the same situation. The development of studies of slang will contribute substantively as a significant component of linguistic and social behaviour and methodologically as a basis for integrating the study of language and society into a unified theoretical framework.

Bū Himāra's European connexion: the commercial relations of a Moroccan warlord

Abstract: The rural rebellion and dissidence of Jilālī ibn Idrīs al-Zarhūnā al-Yūsufī, alias Bū Ḥimāra, was among the most debilitating of the crises to afflict the Moroccan central government (makhzan) during its final decade of freedom from formal French control. Bū Ḥimāra, falsely declaring himself to be Mawlay MuḤammad, older brother of the reigning sultan, and thereby rightful claimant to the Sharifian throne, held sway over much of the northeastern part of the country between 1903 and 1909. Though the rebellion never extended beyond this region, the makhzan's protracted attempts to stamp it out contributed significantly to Morocco's political instability and fiscal collapse. The movement, under Bū Ḥimāra's leadership, may be divided into two major phases: the first, lasting about six months, when the revolt had the character of a mass popular protest against the makhzan; the second, from late 1903 to 1909, when Bū Ḥimāra, with a reduced and fluid band of partisans, settled into the role of regional warlord, ruling over a petty state apparatus in the mountainous Northeast. During the longer second phase, his paramountcy was similar in form and objective to that of other regional strong men who carved out principalities in peripheral areas of the country, building their power on access to modern firearms in defiance of the makhzan. This paper argues that the success and tenacity of Bū Ḥimāra's dissidence was dependent on his ability to develop connexions with the wider world of European commerce: merchandise and commodities trade yielding customs revenue, importation of firearms, relations with Algerian businessmen, and mining concessions. These forms of external support are examined and evaluated, leading to the conclusion that Bū Ḥimāra's principal objective from late 1903 onward was not active rebellion but rather an effort to maintain his political and military captaincy over the Northeast, drawing on whatever external resources were available. Though he successfuly defied the government for several years, his increasing association with European commercial and mining interests undermined his popular support and ultimately led to his downfall.

Colonialism and cultural responses: Problems related to roman provincial analysis

Abstract: The data base of classical period archaeology could be used more effectively when analysed in terms of variable situations involving cultural domination. Definitions and processes related to colonialism, imperialism and various cultural responses by indigenous populations are discussed. Included is an example of such political control in the frontier province of Upper Moesia during the Empire period

Charge-density waves in two- and three-dimensional jellium

Abstract: The stability of the electron gas in jellium against the formation of charge-density waves is studied using the density-functional formalism. Charge-density waves occur in three-dimensional jellium for ${r}_{s}g26$ and in two dimensions for ${r}_{s}g17$ in our approximation. The theory is applied to two-dimensional electron gases on liquid-helium surfaces and in semiconductors.

Unique amino acid composition of Red Sea brine

Abstract: The lack of evidence from terrestrial environments supporting the chemical evolution model has resulted in scientists looking elsewhere in the Solar System and in space for evidence. We have suggested that the Atlantis II Deep brine (21°22′N by 38°05′E) located in a submarine rift at the bottom of the Red Sea is a promising environment possibly containing terrestrial evidence for chemical evolution1. We have also reported finding a thiocyanate concentration of 2.4×10−5 M in the Atlantis II Deep brine2. We report here the discovery of an unusually large concentration of glycine in the Atlantis II Deep brine and virtually no other dissolved free amino acids. We further suggest four possible explanations for the unique amino acid composition of Red Sea brine. Our methods of location, sampling and storage of the brines have been discussed elsewhere2.

Faculty Helpfulness to Students A Comparison of Compliance Techniques

Abstract: A total of 154 randomly chosen faculty members at a large public university served as subjects in a study of compliance by professors to students' request for help. The door-in-the-face technique (large initial request, followed by a moderate request) elicited significantly more compliance than the foot-in-the-door technique (small initial request, followed by a moderate request) and the control technique (moderate request only). The foot-in-the-door technique was significantly less effective than the control technique. The results were viewed conceptually and pragmatically.

Seasonal root growth in the arctic tussock tundra.

Abstract: The quantity of growing root tips per unit of soil volume was analyzed in a central Alaskan tussock tundra site. By June 10, the aboveground fraction of the vegetation had initiated the flush of spring growth and flowering while less than 5 active root tips cm-3 were found. By June 25 this value had increased to 30 root tips cm-3. Similar values in July were followed by a complete cessation of root growth after the first week of August. By then, leaf senescence had also become visible. In the spring, low root temperatures were responsible for the time lag between shoot growth initiation and the beginning of root growth. In early August, root growth stopped in spite of adequate soil temperatures and accumulated carbohydrate for root growth. It is proposed that use of reserve carbohydrate for root growth in August would compromise the flush of spring growth in the following year.

The Concept of Job Analysis: A Review and Some Suggestions:

Abstract: ms a concept, job analysis has had an erratic history. The term first appeared in the l managerial literature around the turn of the century. It enjoyed considerable popularity in the first quarter of this century among industrial engineers, psychologists, and personnel specialists. Thus, an annotated bibliography on the subject published in 1932 contained over 400 references, many of which were published before 1923 (I.R.C., 1932). The concept was discussed at conferences and in professional journals. It formed the backbone of Taylor's scientific management. (See, Uhrbrock, 1922; and Miller and Coghill, 1961: 31-38). Enthusiasm over the subject appears to have lasted into the 1940's. After that, the concept declined in popularity. The literature on the subject published in the 1950's and early 1960's is sparse and limited in its concerns. By and large, job analysis during that period was perceived as an adjunct to wage and salary administration and industrial engineering. It also became technique-bound, being identified largely with observation and time and motion study. (Miller and Coghill, 1961; A.M.A., 1958; and Carroll, 1951). In recent years, job analysis has made a comeback. Renewed interest in the topic was triggered by the civil rights/EEO legislation, which began with the passage of the Civil Rights Act of 1964, and now includes several amendments and supportive enactments. This package of laws now requires that tests and personnel tools must be \"valid.\" More recently, the EEOC has broadened its concerns and is presently investigating selection criteria and job evaluation, both of which are conceptually grounded in job analysis. (See, Hall and Albrecht, 1979; and Miner and Miner, 1979.) While the renewed interest in job analysis is noteworthy, the concept is controversial. Everybody who has written on the subject agrees on the fundamental thrust of job analysis, i.e., to gather information about jobs. However, writers are in disagreement about the types of information that comprises the unique responsibility of the job analyst, the uses to be made of such information, the sequence of steps involved in gathering job related information, and the terminology of job analysis. (See, War Manpower Commission, 1941: 1; U.S. Department of Labor, 1974; Stone and Yoder, 1970: 6; Melching and Borcher, 1973; and Cascio, 1978: 131.) This paper attempts to come to grips with some of the unresolved issues involved in the study and conduct of job analysis. Specifically, an attempt is made to sort out the areas of controversy, and to provide a framework for resolving them.