bluuebunny/crossref_metadata_2025 huggingface dataset:
Americans’ Attitudes Toward Welfare State Spending for Old-Age Programs: An Analysis of Period and Cohort Differences
Authors: Dietz Tracy L. , Castora Melissa
Published: May 2006

Using data from the General Social Survey the current study examines period and cohort differences in attitudes toward welfare state spending for old age programs. Using the Torres-Gil classification system, the study uses cross-sectional data from the 1984–2004 waves of data to identify any differences by period and cohort group membership in whether or not it is the government’s responsibility to provide a decent standard of living for older adults, whether or not respondents felt that the current level of spending for Social Security was adequate, and whether or not respondents were willing to make sacrifices such as paying higher taxes to pay for greater retirement benefits. The findings suggest that the generational conflict that many suggested might arise has not come to fruition. Indeed, the youngest cohorts in these analysis were the most likely to support higher taxes to pay for better retirement benefits. Perhaps more interesting were the findings that there were no significant period effects for whether or not the government was responsible for providing a decent standard of living but there were such effects when examining whether or not Social Security funding levels were adequate.
Association of Cigarette Smoking With HIV Prognosis Among Women in the HAART Era: A Report From the Women’s Interagency HIV Study
Authors: Feldman Joseph G. , Minkoff Howard , Schneider Michael F. , Gange Stephen J. , Cohen Mardge , Watts D. Heather , Gandhi Monica , Mocharnuk Robert S. , Anastos Kathryn
Published: May 2006

Objective. We assessed the association of cigarette smoking with the effectiveness of highly active antiretroviral therapy (HAART) among low-income women.

Methods. Data were analyzed from the Women’s Interagency HIV Study, a multisite longitudinal study up to 7.9 years for 924 women representing 72% of all women who initiated HAART between July 1, 1995, and September 30, 2003.

Results. When Cox’s regression was used after control for age, race, hepatitis C infection, illicit drug use, previous antiretroviral therapy, and previous AIDS, smokers on HAART had poorer viral responses (hazard ratio [HR]=0.79; 95% confidence interval [CI]=0.67, 0.93) and poorer immunologic response (HR=0.85; 95% CI=0.73, 0.99). A greater risk of virologic rebound (HR=1.39; 95% CI=1.06, 1.69) and more frequent immunologic failure (HR=1.52; 95% CI=1.18, 1.96) were also observed among smokers. There was a higher risk of death (HR=1.53; 95% CI=1.08, 2.19) and a higher risk of developing AIDS (HR=1.36; 95% CI=1.07, 1.72) but no significant difference between smokers and nonsmokers in the risk of death due to AIDS.

Conclusions. Some of the benefits provided by HAART are negated in cigarette smokers.
Sexual Orientation, Sexual Abuse, and HIV-Risk Behaviors Among Adolescents in the Pacific Northwest
Authors: Saewyc Elizabeth , Skay Carol , Richens Kimberly , Reis Elizabeth , Poon Colleen , Murphy Aileen
Published: May 2006

Objectives. We explored HIV risk behaviors, sexual orientation, and sexual abuse among 5 school-based cohorts in Seattle, Wash (SEA95 and SEA99:N=7477 and N=6590), and British Columbia (BC92, BC98, and BC03 [weighted]: N=239975, N=281576, and N=265132).

Methods. An HIV risk scale of 7 items assessed risky sexual behaviors and injection drug use. Self-identified sexual orientation included heterosexual, bisexual, gay/lesbian, and, in British Columbia only, mostly heterosexual. Analyses of covariance were conducted separately by gender and were adjusted for age and sexual abuse when comparing means.

Results. Gay/lesbian and bisexual adolescents had higher mean age-adjusted risk scores compared with heterosexual and mostly heterosexual adolescents. After we controlled for sexual abuse history, mean scores were 2 to 4 times higher among abused students than among nonabused students in each sexual orientation group. Age/abuse-adjusted models better explained the variance in risk scores (R2=0.10–0.31), but sexual orientation remained an independent predictor.

Conclusion. Sexual minority adolescents who attended school reported higher HIV risk behaviors, and higher prevalence of sexual victimization may partially explain these risks.
Physical and Sexual Violence During Pregnancy and After Delivery: A Prospective Multistate Study of Women With or at Risk for HIV Infection
Authors: Koenig Linda J. , Whitaker Daniel J. , Royce Rachel A. , Wilson Tracey E. , Ethier Kathleen , Fernandez M. Isabel
Published: May 2006

Objectives. We sought to describe and compare prevalence rates of and risk factors for violence against women during pregnancy and postpartum.

Methods. Physical and sexual violence and violence risk factors were assessed during late pregnancy and 6 months postpartum in a prospective study of pregnant women with (n=336) and without (n=298) HIV in 4 US states.

Results. Overall, 10.6% of women reported having experienced violence, 8.9% during pregnancy and 4.9% after delivery. Of these women, 61.7% were abused only during their pregnancy, 21.7% were repeatedly abused, and 16.7% were abused only after their delivery. Sexual violence rarely occurred in the absence of physical violence. The strongest predictor of violence was engaging in bartered sex (adjusted odds ratio [OR]=5.54; 95% confidence interval [CI] =2.0, 15.4). Other predictors included frequent changes in residence (adjusted OR=1.57; 95% CI=1.1, 2.2), financial support from family or partners (adjusted OR=0.42; 95% CI=0.2, 0.8), and HIV diagnosis during current pregnancy (adjusted OR=0.30; 95% CI=0.1, 0.7).

Conclusions. Women more commonly experienced violence during than after their pregnancy, but violence was best predicted by socioeconomic and behavioral indicators whose influence did not vary over time.
Computerized HIV Preventive Intervention for Adolescents: Indications of Efficacy
Authors: Lightfoot Marguerita , Comulada W. Scott , Stover Gabriel
Published: May 2006

We tested the hypothesis that a computerized intervention would be as efficacious as an in-person, small-group intervention in reducing sexual risk behaviors. The sexual behavior of high-risk adolescents in 3 intervention conditions was examined: (1) computer based, (2) small groups, and (3) control. Adolescents in the computerized intervention were significantly less likely to engage in sexual activity and reported significantly fewer partners. For some youths, computers are a viable way to deliver prevention information and promote skill development.
Assessing the Impact of Federal HIV Prevention Spending on HIV Testing and Awareness
Authors: Linas Benjamin P. , Zheng Hui , Losina Elena , Walensky Rochelle P. , Freedberg Kenneth A.
Published: May 2006

Objectives. The United States allocates more than $900 million annually for the prevention of HIV infection. We assessed the impact of this funding on HIV testing and knowledge.

Methods. We linked data from the Behavioral Risk Factor Surveillance System with tracking of Centers for Disease Control and Prevention (CDC) HIV prevention funding. We developed and validated regression models of the relation between HIV prevention funding to a respondent’s state and the odds that the respondent (1) had been tested for HIV, and (2) was aware of methods to prevent mother-to-child HIV transmission (MTCT).

Results. The odds of having been tested for HIV increased with increased CDC funding to states (P=.009), as did awareness of prevention of MTCT (P=.002). We estimate that CDC HIV prevention funds led to 12.8 million more people being tested for HIV between 1998 and 2003 than would have been tested had all states received funds equal to the lowest quintile of funding.

Conclusions. Federal HIV prevention funds independently correlate with increased HIV testing and knowledge of prevention of MTCT. Proposed reductions in HIV prevention spending would likely have adverse public health consequences.
Aggression and Self‐Regulation of Population Size in Deermice
Authors: Healey Michael C.
Published: May 2006

Sadleir (1965) proposes that seasonal changes in the survival of juvenile deermice are determined by seasonal changes in the aggressiveness of the adult population. The purpose of the study is to examine some of the consequences of Sadleir's hypothesis experimentally. Laboratory studies confirmed Sadleir's observations on seasonal changes in the aggressiveness of male deermice. Similarly, in the laboratory, juvenile deermice grew poorly when competing with adults in their home cage. Further analysis showed that only aggressive males are capable of inhibiting juvenile growth. In order to avoid the crowded conditions and confinement implicit in the laboratory experiments, the relations between adult aggressiveness and juvenile growth and survival was reexamined in field experiments. Artificial populations or docile male deermice were established in field plots. Juveniles were then released onto the plots, and their growth and survival followed. Juveniles again grew poorly when competing with aggressive adults, but in the field juveniles also disappeared rapidly from the experimental plots when the adult population was aggressive. The success of immigrants onto trapped out plots and plots with a resident population was examined as well. Immigrants were more successful in establishing themselves on trapped out plots. All the data collected support Sadleir's hypothesis, and it is concluded that the correlation he drew between adult aggressiveness and juvenile survival is real. The data also provide some clues to the organization of deermouse populations. An organization is proposed in which the social units is an animal and its immediate neighbours. Within the social unit mutual antagonism is reduced. But the members of the unit remain highly aggressive, and are intolerant of any stranger that wanders into their home ranges. The system proposed prevents immigrants from settling, the helps to regulate population size, while conserving energy by reducing antagonism between familiar animals.
Vegetation and Floristic Changes on a Portion of White Oak Lake Bed
Authors: Selm H. R. , Shanks R. E.
Published: May 2006

White Oak Lake, Oak Ridge, Tennessee, was used as a dilution basin for radioactive and chemical wastes from 1943 to 1955, when it was drained. From 1956 to 1960 the vegetation on 3 acres of the dry lake bed was identified, mapped, and clip sample. The plant collections revealed rapid invasion and succession by many species. Cover was almost complete the second year. The initial forb cover, made up chiefly of Polygonum, subsequently declined from 73% to 20%. Juncus and Carex, which provided the major cover in 1957 and 1959 respectively, had declined by 1960. Thickets and open woody stands of Salix developed in the first 2 years after lake was drained. Only a slight correlation was found between the vegetation patterns and the isopleths of known physical or chemical soil characteristics.
Relation of Selaginella Densa to Site, Grazing, and Climate
Authors: Van Dyne G. M. , Vogel W. G.
Published: May 2006

Selaginella densa, small clubmoss, is an important component of central Montana foothill grasslands. In an area where it occupied 10—20% of the soil surface, above—ground biomass was 42—101 g/m2. Soils growing S. densa were shallower, more rocky or gravelly, but less sandy, than soils without this species. High levels of fertility, shading and mulch reduced, but additional water increased, its cover. Contrary to other reports, we found a greater decrease in cover on areas grazed intensively than on areas protected for 4 years. Cover on moderately grazed sites or on adjacent protected areas did not change.
Meditteranean Ecosystems and Vegetation Types in California and Israel
Authors: Naveh Z.
Published: May 2006

A comparison of climate, soils, vegetation, and biotic history of mediterranean ecosytems revealed closest ecological equivalence between the blue oak grassland in California and the vallonea oak grassland in Israel, both mediterranean oak savannas in which overall environmental resemblance seems closest. Ecological amplitude and syndynamics in most other comparable types are similar, but the chamise chaparral on non—calcic brown upland and lithosols differs from its maqui counterpart by its adverse influence on the ecosystem. Annual grasslands in California foothills are comparable to seral batha dwarfshrub and grassland in Israel as human—induced degradation stages of chaparral and maqui. For such ecological comparisons a holistic ecosystem approach seems more suitable than any preconceived phytoclimatic and climax concepts.
Orienting Mechanisms of the Green Frog, Rana Clamitans
Authors: Oldham R. S.
Published: May 2006

Rana Clamitans was studied in Algonquin Park, Ontario, Canada, in an attempt to determine how it locates its breeding site. Frogs congregated in specific areas of marshes during the breeding season, some moving in from 500 yards. Most individuals showed strong fidelity to particular breeding sites and even to particular locations within each site, both within one season and from year to year. When translocated up to 600 yards from their home location, frogs did not move at random but showed a marked tendency to move in the direction of home. Experiments showed that this homing response was significantly reduced in the absence of olfactory cues, but was not impaired by the absence of vocal, hygrotactic, geotacti, or visual stimuli. If individuals were translocated to a foreign site, more than 2 miles from the home location, their behavior depended upon the site of release. Those placed into a foreign pool remained there and within 1 or 2 days of introduction showed a fidelity to the pool similar to that of the natives. Those placed on land, however, did not locate the nearest site efficiently. Unlike natives released in the same situation, most tended to move downhill, or in the absence of a topographic gradient, about 30% of the population oriented towards the closest conspecific chorus. Apparently the foreigners were displaced too far to utilize cues from the home site. Being unfamiliar with the local olfactory stimuli they responded to secondary cues and could not effectively locate the nearest site. Frogs were evidently familiar with certain characteristics of a pool or breeding site and probably used this familiarity annually in orienting to the site. Olfactory characteristics were probably of primary importance to fidelity and orientation.
Seed Germination and Establishment as Affected by Non‐Wettable Soils and Wetting Agents
Authors: Osborn J. , Letey J. , DeBano F. , Terry Earl
Published: May 2006

To study the effects of soil wettability and wetting agents on seed germination and establishment, three substrates (naturally occurring non—wettable soil, and a wettable quartz sand) were placed in small plastic containers and received applications of wetting agent in liquid, wetting agent on perlite, and no treatment as a control. The containers were seeded to wimmera ryegrass and were placed both on a 30° slope and on the level in a controlled temperature chamber (70°F). Seed placed on a non—wettable soil which received no wetting agent treatment failed to germinate in those containers placed on the slope. Good germination occurred on soil which was treated with a wetting agent and on wettable sand. The same are primarily due to water relations; water ran off the sloping non—wettable soils. Wetting agent treatment on the wettable sand reduced both germination and establishment of the tested plants.
Salinity Tolerances of Five Marine Spermatophytes of Redfish Bay, Texas
Authors: McMillan Calvin , Moseley Frank N.
Published: May 2006

Thalassia testudinum Konig and Sims and Halophila engelmanni Aschers. (Hydrocharitaceae); Diplanthera wrightii (Aschers.) Aschers., Ruppia maritima L., and Syringodium filiforme Kutzing (Potamogetonaceae) are the major plants of the highly productive estuaries along the Texas coast. When transplanted to outdoor ponds and to controlled growth rooms, the greatest tolerance to increasing salinity was shown by Diplanthera. Lesser salinity tolerance was shown by Thalassia and Ruppia. Although survival was not complete under all transplant conditions for Syringodium, it showed least tolerance of high salinity. Halophila survived sporadically in the study but showed active growth at high salinity. The distributional patterns of these species in Redfish Bay are partially correlated with their salinity tolerances.
Water Metabolism and Temperature Regulation of the Primitive Heteromyids, Liomys Salvani and Liomys Irroratus
Authors: Hudson Jack W. , Rummel John Austin
Published: May 2006

Liomys salvani is able to maintain its body weight under laboratory conditions without free water when given a diet of wild bird seed, whereas Liomys irroratus is unable to maintain its weight under these same conditions. Both species can maintain weight when permitted to burrow even though free water is not available. The ad libitum water consumption of L. salvani was 5.5% body weight/day under laboratory conditions whereas it was 7.5% day for L. irroratus. The ad libitum consumption for L. irroratus was reduced 62% for individuals allowed to burrow. The average maximum urine concentration of L. salvani was 4,000 milliosmols whereas it was 3,580 for L. irroratus. The pulmocutaneous water loss was approximately the same for both species ranging between 0.90 to 1.03 mg H2O/cc O2 at a TA of 28°C, values comparable to those reported for other heteromyids at comparable ambient temperatures. The average biological half—life of water was the same for both species, ranging from 4 days when supplied with drinking water ad libitum to 6 days when deprived of water. Animals allowed to burrow exhibited a half—life of 6 days when deprived of water. Both L salvani and L. irroratus illustrate the characteristic heteromyid feature of poor tolerance to ambient temperatures above 34°C, though L. salvani is better able to resist lethal body temperatures when hyperthermic than can L. irroratus. Both species tolerated ambient temperature of 0°C for at least 1 hour. L. salvani and L. irroratus have basal metabolic rates 15 and 22%, respectively, below predicted. This reduction is probably characteristic of the heteromyids. The average basal metabolism was 1.12 cc O2/g—hr for L. irroratus and 1.07 cc O2/g—hr for L. salvani weighing 48.1 and 43.8 g respectively. Thermal neutrality extended from 31 to 34°C for both species. The insulation of both species as represented by the slope of the line relating metabolism to ambient temperature was .186 cc O2/g—hr—°C for L. Irroratus, values comparable to other heteromyids of similar body weight.
Light and Temperature Requirements for Diapause Development and Release in Daphnia
Authors: Stross R. G.
Published: May 2006

The light and thermal requirements for diapause development and release in Daphnia pulex were determined for the ephippia from a pseudo—sexual strain cultured in the laboratory and from an autumnal diapausing, bisexual strain in Paul Lake, Michigan. Light was essential for termination of diapause in the laboratory—cultured strain regardless of the temperature or duration of ephippia storage. Ephippia from the lake population were activated by light, but prolonged storage in constant dark eliminated the requirement for light, and thereby implicated photoperiodic control of diapause release. The laboratory population completed diapause development within a period of 3 to 6 weeks when stored in constant dark at 22°C. Storage at 3.5°C in constant dark porlonged diapause. In the Paul Lake strain, low temperature was a requirement for diapause development, and at 3.5°C the eggs were in diapause for a period of 5 or 6 months. The contrasting light and thermal requirements are discussed in the context of environments regulating the duration of diapause in summer and winter diapausing populations of Daphnia.
Some Aspects of the Ecology of Migrant Shorebirds
Authors: Recher Harry F.
Published: May 2006

During migration, shorebirds form dense multispecific aggregations within relatively uniform and limited marine littoral habitats. The amount of available feeding space in the habitats frequented fluctuates widely with the daily and seasonal changes in the tidal rhythm. Shorebird species broadly overlap in their periods of peak abundance, inter— and intrahabitat distributions, and in the food organisms preyed upon. However, the totality of species differences and the transient character of migratory assemblages apparently minimizes interspecific interactions that might result in competitive exclusion. The staggering of peak population densities and differences in distribution is most pronounced among morphologically similar species. The number of individuals and species that occur in an area is apparently determined by the amount of available feeding space and the physical diversity of the habitat. Food appears to be generally abundant relative to the requirements of the birds in all the habitats studied. The environmental conditions encountered during migration and the interactions with other individuals have evidently been important factors in the evolution of morphological and behavioral differences among shorebird species. Individuals must be as able to survive during the nonbreeding season as they are during the breeding season.
Effects of Microclimate on Spring Flowering Phenology
Authors: Jackson Marion T.
Published: May 2006

Sixteen microclimatic stations with differences in slope, exposure, vegetation cover, and seasonal change were established in a heavily dissected 180—acre Indiana tract. Correlations, based on cumulative air temperature duration—summations, were made between microclimatic differences and variation in phenological events. Nine widespread species of spring wildflowers had a collective mean range in dates of first flowering of 7.2 days for all stations. The maximum range for a single species was 11 days. Flowering dates of nine species of a large gorge were retarded an average of 6.0 days in the north—facing slope with respect to the opposing south—facing slope. This 6.0—day difference between gorge slopes 150 ft apart is equal to the expected to occur in about 110 miles of latitude, assuming standard exposures. Six species of the north—facing slope in a small gorge were retarded an average of 2.8 days with respect to the opposing south—facing slope. Flowering on north—facing gorge slopes was retarded more than in gorge bottoms, and upland stations had earlier than normal flowering dates. Mean flowering dates for the entire area were retarded more at cooler locations than warmer slopes were advanced. Air—temperature sums and flowering dates correlated well in a given microclimate. The results suggest that phenological research could be expedited by making observations in diverse microclimates during a few seasons rather than acquiring long—term phenological records.
Factors Influencing the Distribution and Abundance of Hexagenia Nymphs (Ephemeroptera) in a Missouri River Reservoir
Authors: Swanson George A.
Published: May 2006

Abundance of bottom organisms in Lewis and Clark Lake was measured by transect—station and randomly—stratified sampling methods. Samples were collected with modified orange—peel and Ekman dredges, and cores were used to delineate bottom types. Hexagenia nymphs have reached an abundance on the inundated flood plain comparable to populations in natural lakes with suitable habitat. Length frequencies of nymphs, plotted at monthly intervals throughout the summer, suggest a 2—yr life cycle for the major portion of the populations. Concentrations of the fall progeny (1—10 mm) indicate that the early distribution of nymphs is a function of imago activity during oviposition. Distribution of the overwintering nymphs differs considerably from that of the previous fall. Evidence of migration from densely populated shore areas was observed. An interaction of depth, wind, current, and bottom type is influential in redistributing the population.
Heat Pre‐Treatment as a Means of Increasing Germination of Desert Annual Seeds
Authors: Capon Brian , Van Asdall Willard
Published: May 2006

Seeds from nine species of desert annuals native to the Mojave and Sonoran Deserts were stored at constant temperatures of 4°, 20°, 50°, and 75°C. All species except one, when stored at 50°C, reached maximum germination within the first 5 weeks of storage. Seeds stored at 75°C failed to germinate while seeds stored at 4°C gave poor germination, equivalent to fresh seeds. Seeds stored at room temperature (20°C) need 5 months' maturation to achieve comparable germination percentages. The prevalent high temperatures in the following seed dispersal probably promote seed maturation in desert plants.
Plant Pigments in Woodland Soils
Authors: Gorham Eville , Sanger Jon
Published: May 2006

Low concentrations of carotenoids and chlorophyll derivatives and present in the organic matter of surface horizons of woodland soils. Before leaf fall chlorophyll breaks down more rapidly than carotenoids, while the reverse is true in soils. This suggests that the contribution of woodland litter and humus to the organic matter in such sediments is outweighed by contributions from aquatic macrophytes and phytoplankton.
Ground Water and Vegetation in Two Peat Bogs in Northern Minnesota
Authors: Bay Roger R.
Published: May 2006

Plant cover and water quality of bog waters are related to the surrounding ground—water flow systems in two bogs–one perched above and isolated from the regional ground—water system, the other nonperched and continuous with the regional system. The nonperced bog has higher pH, higher specific conductivity, and greater variety in plant cover than the perched bog.
The Energy Budget of a Lizard on a Tree Trunk
Authors: Barlett Peter N. , Gates David M.
Published: May 2006

Lizard and environmental properties which determine the exchange of energy between a lizard and its environment are described and related analytically in the equilibrium state to the lizard temperature. Absorptivities, surface areas, body temperatures, and convection coefficients were determined; metabolic and evaporative energy exchanges estimated for a representative Sceloporus occidentialis. The environmental properties of a particular tree trunk habitat are estimated for a June 21 day and the behavior of S. occidentialis predicted in terms of the positions lizards could assume and maintain their body temperatures within the range characteristic of the population in that habitat. The predictions are compared with field observations.
Prompt Transfers of Cesium‐137 to the Soils of a Tagged Liriodendron Forest
Authors: Waller H. D. , Olson J. S.
Published: May 2006

An inventory of total Cs137 distribution in a 500—m2 tagged tulip poplar (Liriodendron tulipifera) forest at the Oak Ridge National Laboratory showed transfer from trees to soil during the first growing season. About one—third of the maximum amount of radiocesium found in the tree canopy during June was transferred to the forest floor and soil; the remainder moved back into woody tissue (stem and roots) before leaf fall. Losses of radiocesium from the foilage and stems into the plot area through litterfall (55 μc/m2) and rain leaching (13 μc/m2) accounted for almost 8% (68 μc/m2) of total Cs137 (934 μc/m2) introduced into tree boles. However, soil (including roots) and litter sampling at the end of the growing season indicated a much larger quantity (414 μc/m2 or 45% of initial input) already in the surface 30—cm layer of mineral soil. Of the total Cs137 activity found within the mineral soil layer, about half can be physically associated with the tagged trees removal of roots from soil samples and cumulative measurement of surface income at time of soil collection. Much of the remainder can be accounted for by contact exchange, root exudation, root death, and leaching of roots by soil solution.
Population Dynamics of the Walnut Aphid, Chromaphis Juglandicola (KALT.) in Northern California
Authors: Sluss R. R.
Published: May 2006

Populations of waln ut aphids and associated insects were observed over a four year period in several northern California walnut orchards. Temperature, leaflet age, amount of prior aphid feeding and coccinellid predation were found to be the most important factors influencing walnut aphid population changes. Sharp declines in aphid population levels were correlated with high temperatures, especially when several days occur with maxima over 100°F. Temperatures may also affect aphids indirectly by directly affecting coccinellid beetles. Early spring temperatures influence the leafing out of the walnut trees. Cool spring temperatures can delay the leafing out of trees, thus postponing the aphid population increase. Carrying capacity of a leaflet for aphids is defined as a maximum number of aphids that can exist on a leaflet at any one time. This level appears to be determined by factors, other than space. Orchards in different areas and of various varieties, irrigation practices, and general vigor exhibit different carrying capacities for aphids. Factors which influence these levels are age of the leaflet and the amount of prior aphid feeding which has occurred on them. Coccinellid beetles were the most important predators encountered in the study. Examples are discussed where the following conditions prevailed: (1) where coccinellids were not involved, (2) where coccinellid population numbers trailed the aphid number and contributed only by shortening the time during which aphids were at maximal population levels, (3) where coccinellids lengthened the time required for the aphids to reach carrying capacity levels, and in so doing reduced the actual carrying capacities to some degree, (4) where coccinellids were the key factors regulating aphid numbers. Aphid parasitism was not important.
Forb‐Arthropod Food Chains in a One‐Year Experimental Field
Authors: Wiegert Richard G. , Odum Eugene P. , Schnell Jay H.
Published: May 2006

Phosphorous—32 tracer studies of plant—arthropod food chains showed a significant difference in both consumer diversity and grazing pressure between the two dominant plant species on a first—year weed field in South Carolina. Where Heterotheca subaxillaris was the labeled plant 32P was transferred readily to a number of phytophagous insects and secondarily to the predator fauna. Where only Erigeron canadensis was tagged, there was little transfer of the isotope to the consumer populations, with the exceptions of the ant Dorymyrmex and the tree cricket Oceanthus. Dorymyrmex is a predator—scavenger, but also tends the aphids present on Erigeron; this latter habit accounted for the high uptake and unusual retention pattern of 32P by this ant where Erigeron was tagged. Oecanthus was primarily an herbivore, but the data suggest some predation on aphids from Erigeron plants. Very little 32P was transferred to the detritus eaters during the 43 day period of the study. Further support is given for the use of radioisotope to study trophic position of organisms as well as grazing pressure and food chain diversity associated with single species of terrestrial primary producers.
Food, Age, and the Dynamics of a Laboratory Population of Rotifers
Authors: King Charles E.
Published: May 2006

Two clones of the rotifer Euchlanis dilatata were derived from a single parent by parthenogenesis so that in succeeding generations the individuals of one clone (the young orthoclone) were always derived from young parents and those of the other (the old orthoclone) from old parents. These clones were fed four different food concentrations (1.6, 4.9, 16.4, and 49.2 mg/ml) of three different algal species (Chlamydomonas reinhardti, Euglena gracilis, and E. geniculata). Rates of increase, birth, death, survivorship, net reproduction, and generation time were measured for all combinations of these variables. Growth rates of individual animals depend on food concentration and not age or food species. Although population growth rates in mass culture are related to both food species and food concentration, the ultimate density of the population depends only on food concentration. Individuals of the young orthoclone have higher rates of population increase than those of the old orthoclone. When Euchlanis fees upon Chlamydomonas the rates of increase are higher than when Euglena gracilis serves as food. E. gracilis, in turn, leads to higher rates than E. genicultata. The rate of population increase is directly related to the density of food for concentrations up to 16.4 mg/ml, but a further increase in food concentration does not result in a corresponding increase in the rate of population growth. These different rates of increase result more from corresponding differences in net reproduction (number of eggs laid by the average female in her lifetime) than from the schedule of egg laying of survivorship. The different rates of population growth can not be explained by differences in the rate of food intake and must result from either differences in assimilation or chemical differences in the foods themselves.
Ecology of Zooplankton of the Cape Thompson Area Alaska
Authors: Tash Jerry C. , Armitage Kenneth B.
Published: May 2006

In a survey of the physicochemical characteristics, primary productivity and occurrence of zooplankton in fresh and brackish waters of Cape Thompson, Alaska, between June 28, 1960 and August 7, 1961, 14 species of Cladocera and 38 species of Copepoda (13 Calanoida, 11 Cyclopoida and 14 Harpacticoida) were distinguished in collections from 10 lakes, 8 lagoons and 111 pools. Seventy—three percent of all species were monocyclic; 13 per cent dicyclic; 9 per cent tricyclic; and 4 per cent tetracyclic. The maximum of primary production was correlated with maximal numbers of zooplankton, maximal number of eggs per ovigerous female in the Cladocera, and maximal occurrence of copepodids. Many Copedoda produced eggs in late fall and early winter when primary production was low. Autumnal production of eggs by these species may be possible because of storage of energy as lipids during the period of high environmental energy, and use of the stored energy at the end of the developmental period to form eggs. Analysis of community structure among zooplankton showed: 10 species with affinities and 7 interrelated recurrent groups occurred in the lakes; 3 species with affinities and 1 recurrent group occurred in the lagoons; 4 species with affinities and 3 interrelated recurrent groups occurred in the coastal pools; and no species with affinities occurred in the inland pools. One cladoceran, one cyclopoid and one or two calanoid copepods of different genera formed the major recurrent groups. The relationships between recurrent groups were the result of species within those related groups having similar distribution and overlapping developmental cycles. Closely allied species occupied different aquatic habitats, but when congeneric species co—occurred, there were differences in size and life cycles.
Role of Allochthonous Detritus in the Trophic Structure of a Woodland Springbrook Community
Authors: Mninshall G. Wayne
Published: May 2006

The community trophic structure of Morgan's Creek, Meade County, Kentucky was analyzed through regular measurement of standing crops of the chief potential sources of plant materials available to the animals (suspended particulate, attached particulate, and allochthonous leaf materials) and an examination of their gut contents. The most important food was allochthonous leaf materials, which occurred as suspended material in the water, as a component of materials attached to the streambed, and as whole leaves and fragments. Diatoms were the only other important source of plant materials and constituted the greatest proportion of the attached organic fraction. Mean standing crop measurements of potential foods for five sampling stations ranged from 0.6 to 1.0 kcal/m3 for suspended particulate organic matter; 12 to 19 kcal/m2 for attached particulate organic matter; and 4.7 to 13 kcal/m2 for allochthonous leaf materials. Comparison of standing crop data with previous findings indicates that the values generally are within the known ranges for flowing waters. Analysis of gut contents and determination of the principal pathways of energy flow in the stream indicate that imported organic matter in the form of allochthonous leaf materials provides the main source of energy for the primary consumers and, indirectly, for the entire benthic community of Morgan's Creek. Of the 37 taxa of animals studied, 24 were herbivores, 5 omnivores, and 8 carnivores. In general, detritus made up from 50 to 100% of all the materials ingested by both the herbivores and omnivores. The total number of benthic animals was comprised of 14% herbivores, 83% omnivores, and 3% carnivores. Gammarus minus was the single most important member of the fauna. It contributed 81% of the total number of invertebrates, and well over 90% of its diet consisted of allochthonous leaf detritus.
Preliminary Experiments on Physical Tolerances of Eggs of Lizards and Snakes
Authors: Fitch Henry S. , Fitch Alice V.
Published: May 2006

In lizards and snakes the egg is a vulnerable stage in the life cycle with limitations that must often restrict geographic range or local occurrence of a species. Eggs of the rat snake, racer, ring—necked snake, Great Plains skink and five—linked skink were exposed in mixed groups to various controlled conditions of temperature and humidity to determine some of the differences between species in their ranges of tolerance. In atmospheres of 60 to 90% relative humidity eggs of all kinds tested lost water rapidly over periods of days and were short—lived. Mold contributed to mortality. At higher humidities survival was prolonged. At 97.5% relative humidity eggs dehydrated slowly but sometimes survived for several weeks and produced normal hatchlings. The small, thin—shelled eggs of ring—necked snakes deteriorated much more rapidly than eggs of the other species tested, and those of the racer were most resistant. In incubation media of decaying wood, loamy humans, crushed limestone and sand, with water content of 2 to 68%, eggs of all kinds tested gained weight by absorption of moisture and most eventually hatched. Gains in weight were gradual and were not proportional to the moisture content of the medium. For all species tested the eggs were eury—thermal with limits of tolerance near 41@?C and lower limits near the freezing point, but there were minor differences between species, and for the ring—necked snake the range of tolerance was several degrees narrower that it was for the skinks. For the egg, temperature is much less limiting than moisture.
Relative Movements of Lizards in Natural Populations as Determined from Recapture Radii
Authors: Tinkle Donald W. , Woodward Donald W.
Published: May 2006

The mean recapture radius has been shown to be an accurate measure of the degree of movements in populations of the lizard Uta stansburiana. It is relatively constant for differing numbers of captures, different numbers of individuals, different years in the same study area and for different periods of time. It is sensitive to density with which it varies inversely. Differences in the mean recapture radii for males and females of 4 populations of Uta stansburiana are presented and discussed. Differences between these populations were particularly correlated to differences in the social behavior of this species in different parts of its range.
Comparative Efficiencies of Van Veen and Smith‐McIntyre Grab Samplers as Revealed by Motion Pictures
Authors: Wigley Roland L.
Published: May 2006

Two commonly used benthos samplers, van Veen and Smith—McIntyre, were tested to detect possible adverse characteristics for sampling epibenthic animals. A strong hydraulic disturbance (shock wave) was formed below the van Veen sampler as it descended through the water toward bottom. In this sampler the shock wave was sufficiently strong to force aside unattached benthic animals as long as 8 cm. The Smith—McIntypre sampler created only a weak, oscillatory shock wave. Available information indicates that, under standard operating procedures, the smaller the screened opening in the top of the sampler's jaws the stronger the shock wave.
Competition in Experimental Populations of Weeds with Emphasis on the Regulation of Population Size
Authors: Palmblad I. G.
Published: May 2006

Several factors, singly or synergistically, may influence the behavior of weedy species under conditions of intraspecific competition. The species studied were Bromus inermis, B. tectorum, Capsella bursa—pastoris, Conyza canadensis, Plantago lanceolata, P. major, Senecio sylvaticus, S. viscosus, and Silene anglica. Some or all of the species were subjected to conditions of intraspecific competition involving variable regimes of: (1) seed—sowing density, (2) soil surface, (3) fertilizer, (4) moisture, and (5) habitat, i.e., greenhouse and non—greenhouse conditions. Initially the vegetative dry weight production per unit area increased as density increased for every species. After a certain density (relative to the species) was reached, production was independent of density. All species displayed considerable plasticity in that similar genotypes showed a great increases in seed production between high and low densities (e.g., over a 100—fold increase for Capsella bursa—pastoris). Mean seed weight was constant under variable conditions of density, fertilizer, soil surface, and moisture in al species except Bromus tectorum. In mixed stands, the population of each species is smaller than its potential maximum. The size of the population of seedlings may be determined by the number of microenvironments suitable for germination (safe—sites) in an area. The populations of the respective species may be further regulated by: (1) self—controlled germination (Bromus inermis, Conyza canadensis, Plantago lanceolata, and Silene anglica); (2) mortality (Plantago major); and (3) individual plasticity (Bromus tectorum, Capsella bursa—pastoris, Senecio sylvaticus, and S. viscosus).
Diurnal Periodicity in the Drift of a Day‐Active Stream Invertebrate
Authors: Waters Thomas F.
Published: May 2006

Diurnal periodicity in the drift of invertebrate was observed in Temple Fork (of the Logan River), a small Utah mountain stream in the summer of 1966. The larvae of a caddisfly, Oligophlebodes sigma Milne (Trichoptera: Limnephilidae) exhibited a marked day—active drift periodicity, a type rarely reported. Drift rates as high as 400 g (160,000 individuals) per 24 hr for the entire stream (discharge about 0.34 m3/sec) were recorded, with only 4% occurring during the night. Inflections in drift rate were not related to times of sunset or sunrise, as is the case with night—active species. Rather, a close positive correlation with water temperatures, normally higher during the daytime, was apparent. Such correlation suggests that, whereas light intensity is the phase—setting mechanism for night—active drift periodicities, in the present case of a day—active pattern, the phase—setting mechanism was water temperature.
Use of Biomass Units in Shannon's Formula
Authors: Wilhm Jerry L.
Published: May 2006

Species diversity of a population of benthic macroinvertebrates was described with Shannon's formula. The index was compared with basic data as numbers of individuals versus basic data as biomass units.
Gluconeogenesis in the Oriental Hornet Vespa Orientalis F
Authors: Ishay J. , Ikan R.
Published: May 2006

Adults and larvae of the Oriental Hornet (Vespa orientalis F.) have been fed on C14—labeled protein, derived from Chlorella, in order to determine to what extent such protein may be converted into carbohydrates. Only larvae were found capable of converting the labeled protein. Products of this conversion were the sugars glucose, fructose and sucrose, and also tri— and tetrasaccharides as yet unidentified. It is suggested that this ability of the larvae to carry out gluconeogenesis and the subsequent transfer of the formed sugars to the adults (in saliva droplets) may play an important part in the adult—larva interrelations of various insect societies.
Ecology of Mima‐Type Mounds in Northwestern Minnesota
Authors: Ross B. A. , Tester J. R. , Breckenridge W. J.
Published: May 2006

This paper reports on the physiognomy, soils, microclimate, vegetation and animal activity on Mima mounds in Minnesota and presents an hypothesis on origin of these mounds. The mounds vary from 10 to 130 feet in maximum dimension and from 6 to 50 inches in height and occur at a density of about one per acre on 210.5 acres of upland native prairie. Mound vegetation is always distinctly dominated by either grasses, forbs or the shrub, Symphoricarpos occidentalis. The most striking feature of most of the mounds is the disturbance on their soil by pocket gophers (Geomys bursarius), ground squirrels (Citellus spp.), badgers (Taxidae taxus), toads (Bufo hemiophrys) and other animals. This has probably caused the change in vegetation, the lower bulk density, the lack of soil structure, and the increased water permeability. Animal disturbance of the soil may also account for the lack of sod, the high organic content of the subsurface silt loam, the zone of gradation of silt into clay, the discontinuity of the zone of carbonate concentration, and most of the anomalies such as pockets of pebbles. Comparison of the mound and adjacent prairie soils suggests that the mounds are, in effect, puffs of soil formed primarily by animals disturbing and mixing the soil in a particular sport.
An Examination of Some Ordination Problems By Use of Simulated Vegetational Data
Authors: Swan J. M. A.
Published: May 2006

Hypothetical vegetation models were made to simulate numerical changes in species populations along a single environmental gradient. A single ordination procedure was evaluated by its ability to detect the ecological information in the hypothetical models. The procedure was reasonably successful when the data were drawn from a short length of the gradient but became progressively less so as longer lengths of the environmental gradient were included in the data. This parallels an increase in the number of stands from which each species is absent in the total data set. Zero values appear to mask ecological information, and an intuitive method of assigning "degree of absence" values to the data is described. After this adjustment, ordination patterns were easier to interpret because ecological information was concentrated in fewer axes.
Artificial Selection for Dispersal in Flour Beetles (Tenebrionidae: Tribolium)
Authors: Ogden John C.
Published: May 2006

The selection scheme employed a two—vial apparatus in which beetles (Tribolium castaneum (CS) and T. confusum (CF)) could move in one direction between vials. One inactive line and one active line were selected for five generations in both species. A second active line in which selection for activity was more intense was selected for three generations in both species. In CS, both active lines differed significantly from the controls. The inactive line approached a significant difference. In CF, only the second active line attained a significant difference from control level. The responses developed by this selection procedure apparently were not due to reactivity to conditioned medium.
A Conductivity Method for Measuring Microbially Evolved Carbon Dioxide
Authors: Wollum A. G. , Gomez J. E.
Published: May 2006

The advantages of the electrical conductivity procedure proposed for the measurement of microbially evolved CO2, previously absorbed in alkali, are that it is rapid and the exposure time to atmospheric CO2 is only a few seconds. It is as accurate as other accepted techniques.