Showing papers by "San Diego State University published in 1979"

The record of Cenozoic volcanism around the Gulf of California

Abstract: Potassium/argon dating and chemical analyses of major oxides of volcanic rocks in areas adjacent to the Gulf of California provide a stratigraphic record of tectonic and magmatic evolution that has occurred during the past 30 m.y. The important volcanic provinces are: the Pliocene-Holocene Gulf of California dacite; the Pliocene-Holocene west Baja California alkaline basalt-andesite; the Trans-Mexican Volcanic Belt; the “proto-Gulf” basalt from the coast of Nayarit; the late Miocene alkaline basalt of the Commondu Formation found in the Peninsula; the late Miocene basalt-andesite-rhyolite rocks straddling the northern half of the Gulf; the 18- to 22-m.y.-old hornblende andesite belt in the Peninsula of Baja California and the central coast of Sonora; and the Oligocene–early Miocene basalt-rhyolite belt, largely east of the Gulf. Tectonics interpretation suggests that the subduction plane moved westward between Oligocene and middle Miocene time and that active calc-alkaline volcanism continued over a broad area around the northern Gulf even after the trench west of Baja California had been annihilated.

Kinetics and mechanism of the silane decomposition

Abstract: The homogeneous gas-phase decomposition kinetics of silane has been investigated using the single-pulse shock tube comparative rate technique (T = 1035–1184˚K, Ptotal ≈ 4000 Torr) The initial reaction of the decomposition SiH4 SiH2 + H2 is a unimolecular process in its pressure fall-off regime with experimental Arrhenius parameters of logk1 (sec−1) = 1333 ± 028–52,700 ± 1400/2303RT The decomposition has also been studied at lower temperatures by conventional methods The results confirm the total pressure effect, indicate a small but not negligible extent of induced reaction, and show that the decomposition is first order in silane at constant total pressures RRKM-pressure fall-off calculations for four different transition-state models are reported, and good agreement with all the data is obtained with a model whose high-pressure parameters are logA1 (sec−1) = 155, E1(∞) = 569 kcal, and ΔE0±0(1) = 559 kcal The mechanism of the decomposition is discussed, and it is concluded that hydrogen atoms are not involved It is further suggested that silylene in the pure silane pyrolysis ultimately reacts with itself to give hydrogen: 2SiH2 → (Si2H4)* → (SiH3SiH)* → Si2H2 + H2 The mechanism of H ⟷ D exchange absorbed in the pyrolysis of SiD4-hydrocarbon systems is also discussed

Precipitation over the Pacific Ocean, 30°S to 60°N

Abstract: By using present weather observations taken by ships and relating them to a given amount of precipitation, new estimates of oceanic rainfall for the Pacific Ocean between 30°S and 60°N have been derived. Satellite microwave measurements and Taylor's (1973) island analysis support our findings. Annual and quarterly rainfall maps, drawn from our estimates, agree with other modem, land-derived values, but provide greater detail. Between the equator and 60°N, the annual depth and volume rainfall totals are 1282 mm and 1.16×105 km3, respectively. Maps of amplitude and phase show that most of the rainfall north of 28°N occurs in winter, while maximum rainfall occurs in July and August in the tropics. Diurnal rainfall, studied at selected locations, is at a minimum at noon in all but the western pan of the North Pacific. Here there is no distinct minimum.

Geometry of Rivers in Regime

Abstract: An analytical method has been developed for computing the self-adjusted geometry of sand-bed rivers based upon a sediment discharge formula, a flow resistance relationship, and the concept of minimum stream power. Regime rivers with low values of discharge Q and slope S are characterized by small width-depth ratios (generally less than 30) that are not sensitive to the change in slope or discharge. Most regime canals belong to this category. But for larger values of Q or S, or both, the results show that regime rivers may have large width-depth ratios sensitive to the changes in Q or S. As Q or S increases the width-depth ratio of a regime river may become so large that it indicates a braided channel pattern. However, a much smaller width-depth ratio under this situation is also a possible stable geometry. The stable geometry was obtained from the stream power analysis wherein each stable configuration is assumed to correspond to a minimum stream power for the given constraints.

Plant Water Relations in Montane and Tussock Tundra Vegetation Types in Alaska

Abstract: The objective of this study was to measure plant water potentials and related environmental factors in different montane tundra types occurring in a gradient of snow accumulation and in tussock tun...

The Interests Served B Y Technological Reform: The Case of Computing

Abstract: This study explores the interests served by technological reform through an empirical analysis of power shifts stemming from the use of computer technology in American local governments. Alternative hypotheses concerning the existence and direction of power shifts are tested with survey and observational data collected in 42 U.S. cities. The findings indicate that computer-based systems tend to follow and reinforce the existing pattern of local government power relationships, whether that pattern be pluralistic or centralized in bureaucrats, technocrats, or politicians. Consequently, computing tends to support the interests of the status quo versus the interests of reform.

A growth profile for the rock scallop Hinnites multirugosus held at several depths off La Jolla, California

Abstract: Juvenile Hinnites multirugosus were held in cages secured at 6 depths (maximum 120 m) to a buoyed line in the ocean 5 km off Scripps Institution of Oceanography for 95 days (August–November, 1977). The line was retrieved on December 2, and the scallops were measured, weighed and sacrificed for internal study. A second similar line, lowered at the same time as the first, was allowed to remain at the station for observation until later in 1978. Scallops at the shallowest depths (8, 15, and 30 m) displayed the most rapid growth, groups (n=10) averaging 19.3, 25.5 and 21.7 mm increases in shell diameter, respectively. These growth rates were comparable to the best results for scallops held in food-rich waters of Mission Bay, San Diego, California. Groups at the deeper levels (60, 90 and 120 m) grew by averages of 15.3, 8.5 and 7.8 mm, respectively. Growth was less than expected at 8 m, presumably due largely to competition for food and growing space by fouling organisms (barnacles, bryozoans, hydroids and colonial tunicates). Fouling was minimal at depths exceeding 30 m. The known vertical distribution of temperature and particulate organic matter in the ocean off La Jolla indicates that both influenced scallop growth in this study. A temperature range of 5 to 10 C° from the surface to a depth of 100 m is common to the area. Phytoplankton are generally concentrated in the upper 50 m.

Some Assumed Characteristics of Voluntarily Childfree Women and Men

Abstract: Two experiments were conducted to assess students' perceptions from written descriptions of voluntarily childfree women and men. In Experiment 1, a sterilized, childfree wife was rated as less sensitive and loving, less typical an American woman, more likely to be active in women's liberation (ps < .01), and as less happy, less well-adjusted, less likely to get along with her parents, and less likely to be happy and satisfied at age 65 (ps < .05), relative to an otherwise identically described mother of two. In Experiment 2, similar differential trait ascriptions appeared for both childfree men and women. In fact, ratings of the childfree man were less favorable than those for the childfree woman, suggesting possible greater bias against childfree men than women.

The Interaction of Field Independence with Discovery Learning in Mathematics

Abstract: This study tested the hypothesis that students with a field-independent cognitive style would learn most about numeration systems if they had minimum guidance and maximum opportunity for discovery through the use of manipulative materials. Field-dependent students were expected to perform best with maximum guidance and a symbolic treatment. Data were gathered on 46 prospective elementary school teachers who had been randomly assigned to the two treatment groups. Multiple regression analysis revealed a significant disordinal interaction for one of two achievement measures. The interaction supported the hypothesis that field-independent students achieve most in a discovery treatment, and field-dependent students learn best in expository instruction.

Is It the Cognitive or the Behavioral Component Which Makes Cognitive-Behavior Modification Effective in Test Anxiety?.

Abstract: Components of Meichenbaum's cognitive-behavior modification treatment for test anxiety were varied in a 2 × 2 factorial design. Desensitization and cognitive treatments were either given or not given. The resultant conditions were (a) desensitization only, (b) cognitive only, (c) the combination cognitive plus desensitization,, and (d) neither cognitive nor desensitization (control). Each test-anxious subject was randomly assigned to one of the four groups. On a variety of test anxiety and self-rating measures the combined treatment and desensitization were less effective than the cognitive-only treatment. The results are discussed as consistent with traditional theories of test anxiety and antithetical to a recent behavioral reformulation of test anxiety theory.

Water relations of five tropical tree species on Barro Colorado Island, Panama.

Abstract: Diurnal curves of xylem pressure potential (P) and leaf conductance (C) were measured for five tree species of the lowland tropical forest on Barro Colorado Island, Panama. Measurements were taken just before and just after the beginning of the rainy season. The species studied were: Cordia alliodora, Faramea occidentalis, Heisteria concinna, Macquira costaricana, and Trichilia cipo.For all species, predawn (base P) and daytime values of P increased markedly after the beginning of the rainy season. Diurnal patterns of C were quite diverse. C. alliodora showed a decline in C during the day whereas F. occidentaus, H. concinna, and M. costaricana showed little change. Conductance of the last three species was lower before the first rains. T. cipo exhibited more complicated behavior for P and C. Before the rainy season, low values of base P and midday P were observed (-26 bars and-39 bars, respectively). Conductance was also low. After the first rains, base P increased to-4 bars. At this time, midday P and C appeared to respond to vapor pressure deficit (VPD), being less on a day with high VPD than on a day with low VPD.

Drainage‐basin evolution and aquifer development in a karstic limestone terrain South‐Central Texas, U.S.A.

Abstract: The Edwards artesian aquifer occurs in cavernous limestones of Cretaceous (Albian) age within the Balcones fault zone in south-central Texas. The major recharge and discharge zones of the aquifer are contained within the upper reaches of three river systems: the Nueces, the San Antonio, and the Guadalupe. Within these watersheds, recharge dominates in the semiarid Nueces basin to the west while most discharge occurs farther east from wells in the subhumid San Antonio basin and from springs in the subhumid Guadalupe basin. This long-distance transfer of ground water (up to 240 km) is a result of several factors: depositional and early diagenetic history of the limestone host rock, geometry and magnitudes of fault displacement, and physiographic responses to faulting. The loci of greatest discharge from the aquifer occur in an area that was exposed subaerially with concomitant porosity enhancement due to dissolution of limestone during late Early Cretaceous time. This area also was subjected to the greatest fault displacement during Miocene time. Thus, faults and associated joints superimposed additional avenues for porosity and permeability development onto an area that already had considerable secondary porosity. Further determinants on aquifer properties resulted from late Tertiary and Quaternary drainage evolution in response to faulting along the Balcones trend. The strike of the fault zone lay at acute angles to the courses of the main trunk streams in the ancestral Guadalupe and San Antonio River systems, whereas in the Nueces basin the trend of the fault zone was normal to the courses of the main streams. Thus, as a fault-line scarp began to form in the eatern basins, scarp-normal streams were incised rapidly into northwest-trending canyons. These steep-gradient streams captured the eastward-flowing major streams in the easten watersheds. These pirate streams incised into the aquifer at the lowest topographic levels within the region because of: 1. The sudden acquisition of extensive catchment areas in a subhumid area; and 2. Steep stream gradients that reflected the larger fault displacement in the east. The low topographic points of discharge became the loci of major springs. Recharge is dominant in the Nueces basin mainly because streams cross permeable limestone units at higher topographic levels than in the San Antonio and Guadalupe basins. The topographic characteristics of the Nueces watershed resulted from a combination of diverse factors: lesser fault displacement, no major stream piracy, and less vigorous erosion because of a semiarid climate.

The Male Physique and Behavioral Expectancies

Abstract: (1979). The Male Physique and Behavioral Expectancies. The Journal of Psychology: Vol. 101, No. 1, pp. 97-102.

Ground-water recharge to the aquifers of northern San Luis Valley, Colorado: Summary

Abstract: The northern San Luis Drainage Basin, which includes the northern closed basin of San Luis Valley and contributing watersheds of the, Sangre de Cristo and San Juan Mountains.(Fig. 1), is a high mountain basin encompassing about 8,400 sq km of south-central Colorado. The basin is located 210 km southwest of Denver, along the Rio Grande Rift Zone, a zone of Cenozoic normal faulting, volcanic activity, and high heat flow (Chapin, 1971). The basin is bounded on the east and west by the surface water divides of the Sangre de Cristo and San Juan Mountains, respectively, on the north by Poncha Pass, and on the south by a shallow ground- and surface-water divide north of the Rio Grande River. The aquifers of San Luis Valley have undergone rapid development since the discovery of artesian water in 1887. A definition of the sources of ground-water recharge to these aquifers is necessary for the rational management of both the developed and potential resources of the valley. More important perhaps is that the ground-water recharge system must be understood before the relations between aquifer development and flow in the Rio Grande can be defined and used to meet Colorado9s obligations to New Mexico under the 1938 Rio Grande Compact. Although several studies have discussed the hydrogeology of portions of the valley (Siebenthal, 1910; Powell, 1958), the ground-water chemistry of the valley (Klein, 1971; Glanzman, 1972; Emery and others, 1973), and the general hydrology of the valley (Emery and others, 1969, 1971, 1972, 1973), this is the first such study to focus specifically on the ground-water recharge system of the northern San Luis Basin.

An examination of voter conceptualizations of the ideal political candidate

Abstract: This study was designed to determine the nature of the ideal political candidate, employing source credibility and homophily as a basis for analysis. It was demonstrated that the ideal political candidate is seen as extremely competent, extremely high in character, quite composed and sociable, slightly extroverted, as well as slightly similar to the voters in attitudes and beliefs and neutral in similarity in terms of background and personality. Implications of the findings and suggestions for future research were advanced.

Role of extended perceptual experience upon haptic perception of nonrepresentational shapes.

Abstract: The influence of amount and type of exploratory activity upon 3 male and 5 female undergraduates' ability to detect the symmaterical or asymmetrical characteristics of individually presented plastic nonrepresentational shapes was examined. A decrease in scanning time and number of identification errors between the first and fourth days of testing indicates that extended perceptual experience plays a major role in the efficient pick-up and utilization of haptic information. A signal-detection analysis demonstrated that the use of a simultaneous-apprehension scanning strategy resulted in greater sensitivity to asymmetrical shapes than did the use of a simultaneous-apprehension scan. The data support the hypothesis that experience, the form parameter of symmetry, and the type of scanning strategy used to explore a stimulus function together to influence haptic perception of nonrepresentational shapes.

Thiocyanate in Red Sea brine and its implications

Abstract: THE Oparin–Haldane hypothesis about the origin of life has provided a rational theoretical model for laboratory research. Almost thirty years of experiments have supported this hypothesis. Verification of the hypothesis in terrestrial environments, however, has not been documented. Some environments such as thermal springs in the Kuril Islands have been reported to have possible chemical precursors but lack of sterility and other factors have not made it possible to establish evidence for natural, terrestrial abiotic synthesis1. We identify here the Atlantis II Deep brine as a promising site for searching for chemical precursors, report finding thiocyanate in the brine and suggest a relationship between chemical evolution and the evolution of the Earth's crust.

Distribution, movement and diet of the snailSearlesia dira in the intertidal community of San Juan Island, Puget Sound, Washington

Abstract: Searlesia dira Reeve is a locally abundant, carnivorous gastropod that occurs from Alaska to central California. I studied populations of this snail at a variety of sites on San Juan Island in order to provide information on their distribution and abundance and to analyze their community role, i.e., their potential impact on their prey populations and their dietary overlap with co-occurring invertebrate predators. I established permanent transects, both random and in crevices, at three areas of differing exposure to wave action. On these transects I recorded the number and size ofS. dira, activity, distance to nearest neighbor, other organisms present, and tidal height on four phases of the mixed semi-diurnal tidal cycle. The results are (1) an increase in density with increase in substrate relief, (2) an occurrence of highest densities in moderately exposed and exposed sites rather than in protected ones, (3) an increase in mean size with increase in depth along the intertidal gradient, (4) an increase in both total activity and feeding success on the high water immediately following an extreme minus low tide occurring during the daytime in the summer, (5) a relative restriction of feeding success to that high tide, and (6) a similarity of the diet to the relative abundance of the main observed prey for most areas. The main exceptions are chitons and one lower intertidal limpet, all of which are taken in excess of their apparent abundance and especially in the middle intertidal. The upward extension of some lower intertidal prey populations, such as chitons, may be limited by the increased susceptibility of individuals at the upper margin of the population to predators such asS. dira; susceptibility appears to be increased after periods with a higher probability of increased physiological stress, such as extreme low tides on summer days.

Academic Achievement of Recent Immigrants from Mexico

Abstract: The academic achievement of recent immigrants from Mexico is a problem which has not been adequately studied and which may have important implications for bilingual education. Previous research seems to indicate that recent immigrants outperform native-born Mexican Americans. This study, however, presents evidence from research conducted at the junior high school level which contradicts previous findings concerning the relative superiority of recent Mexican immigrants. It was found that recent immigrants in the present sample attained significantly lower levels of academic achievement than native-born Mexican Americans. The problem of the relative achievement levels of these two groups is discussed in the context of three possible explanations: (a) socioeconomic differences, (b) the teacher expectancy effect, and (c) the native language theory. It is concluded that limited instruction in the home language of the child during the early primary years, followed by an abrupt shift to instruction in a second l...