Support for maternal manipulation of developmental nutrition in a facultatively eusocial bee, <Emphasis Type="Italic">Megalopta genalis</Emphasis> (Halictidae)

Developmental maternal effects are a potentially important source of phenotypic variation, but they can be difficult to distinguish from other environmental factors. This is an important distinction within the context of social evolution, because if variation in offspring helping behavior is due to maternal manipulation, social selection may act on maternal phenotypes, as well as those of offspring. Factors correlated with social castes have been linked to variation in developmental nutrition, which might provide opportunity for females to manipulate the social behavior of their offspring. Megalopta genalis is a mass-provisioning facultatively eusocial sweat bee for which production of males and females in social and solitary nests is concurrent and asynchronous. Female offspring may become either gynes (reproductive dispersers) or workers (non-reproductive helpers). We predicted that if maternal manipulation plays a role in M. genalis caste determination, investment in daughters should vary more than for sons. The mass and protein content of pollen stores provided to female offspring varied significantly more than those of males, but volume and sugar content did not. Sugar content varied more among female eggs in social nests than in solitary nests. Provisions were larger, with higher nutrient content, for female eggs and in social nests. Adult females and males show different patterns of allometry, and their investment ratio ranged from 1.23 to 1.69. Adult body weight varied more for females than males, possibly reflecting increased variation in maternal investment in female offspring. These differences are consistent with a role for maternal manipulation in the social plasticity observed in M. genalis.     

Sources of polycyclic aromatic hydrocarbons (PAHs) in sediments of the Biobio River in south central Chile

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment; there are concerns about them due to their toxic properties. Human activities could significantly contribute to the total PAH burden in river sediments. In this work, we document the analysis of PAHs in sediments taken in the middle stretch of the Biobio River in south central Chile. This river is a principal system, draining more than 24,000 km² and subjected to a diverse variety of human-made stressors (pulp mill and urban effluents, agricultural drainage systems, etc). During 2003, several sediment samples were taken in more than 45 sampling sites located in the river’s middle stretch. Due to the granulometric characteristics (mainly sandy sediments), only 17 samples were analyzed, taking into consideration the presence of a fine section within the sediment sample. Using HPLC with fluorescence detection, 15 EPA priority PAHs and perylene were analyzed. The composition of PAHs in the sediment samples is rather similar between sites and levels averaged 104 ± 78 ng g⁻¹ d.w. The highest levels were detected downstream from an industrial discharge. A good correlation was observed between PAH levels and organic carbon content in the tested sediments; however, concentrations above 134 ng g⁻¹ d.w. did not indicate correlation. The samples PAH ratios (Flu/Pyr and Chr/B(a)A) reveal a strong pyrolytic PAH pattern in the sediments tested, supporting evidence indicating that PAHs come mainly from pyrolytic sources. This result contrasts with previous records that have shown a natural influence in the upper basin and a petrogenic pattern near the mouth.     

Nutritionally relevant elements in staple foods: influence of arable site versus choice of variety

Eighteen representative sites for the Austrian grain-growing and eight for the potato-growing zones (soils and crops) were investigated. On each site, total element contents (B, Ba, Ca, Cd, Co, Cu, Fe, K, Li, Mg, Mn, Mo, Na, P, Sr and Zn) were determined in 4–12 varieties of winter wheat (n = 136), 6 varieties of spring durum wheat (n = 30), 5 varieties of winter durum wheat (n = 15), 7 varieties of rye (n = 49), 5 varieties of spring barley (n = 30) and 5 varieties of potatoes (n = 40). Element accumulations in grain species and potato tubers varied significantly with site conditions, with the main exceptions for B in potatoes and wheat as well as for Zn, Cu and Co in durum wheat. On average, across all investigated sites, differences in varieties occurred concerning the elements Ca, Cd, Ba, Sr and Zn (except Zn in potatoes and winter durum). A rough estimation revealed that an average Austrian consumer of wheat, rye and potatoes meets more than 50% of the needs of daily element intake for K, P and Mg, between 36 and 72% for Fe, Zn and Cu, and more than 100% for Co, Mo and Mn. In particular, the elements Ca and Na have to be added from other sources.     

Clearance rates of the great scallop (<Emphasis Type="Italic">Pecten maximus</Emphasis>) and blue mussel (<Emphasis Type="Italic">Mytilus edulis</Emphasis>) at low natural seston concentrations

Great scallop, Pecten maximus, and blue mussel, Mytilus edulis, clearance rate (CR) responses to low natural seston concentrations were investigated in the laboratory to study (1) short-term CR variations in individual bivalves exposed to a single low seston diet, and (2) seasonal variations in average CR responses of bivalve cohorts to natural environmental variations. On a short temporal scale, mean CR response of both species to 0.06 μg L⁻¹ chlorophyll a (Chl a) and 0.23 mg L⁻¹ suspended particulate matter (SPM) remained constant despite large intra-individual fluctuations in CR. In the seasonal study, cohorts of each species were exposed to four seston treatments consisting of ambient and diluted natural seston that ranged in mean concentration from 0.15 to 0.43 mg L⁻¹ SPM, 0.01 to 0.88 μg L⁻¹ Chl a, 36 to 131 μg L⁻¹ particulate organic carbon and 0.019 to 0.330 mm³ L⁻¹ particle volume. Although food abundance in all treatments was low, the nutritional quality of the seston was relatively high (e.g., mean particulate organic content ranged from 68 to 75%). Under these low seston conditions, a high percentage of P. maximus (81–98%) and M. edulis (67–97%) actively cleared particles at mean rates between 9 and 12 and between 4 and 6 L g⁻¹ h⁻¹, respectively. For both species, minimum mean CR values were obtained for animals exposed to the lowest seston concentrations. Within treatments, P. maximus showed a greater degree of seasonality in CR than M. edulis, which fed at a relatively constant rate despite seasonal changes in food and temperature. P. maximus showed a non-linear CR response to increasing Chl a levels, with rates increasing to a maximum at approximately 0.4 μg L⁻¹ Chl a and then decreasing as food quantity continued to increase. Mean CR of M. edulis also peaked at a similar concentration, but remained high and stable as the food supply continued to increase and as temperatures varied between 4.6 and 19.6°C. The results show that P. maximus and M. edulis from a low seston environment, do not stop suspension-feeding at very low seston quantities; a result that contradicts previous conclusions on the suspension-feeding behavior of bivalve mollusks and which is pertinent to interpreting the biogeographic distribution of bivalve mollusks and site suitability for aquaculture.     

Vertical migration of radionuclides in undisturbed grassland soils

Literature data on numerical values obtained for the parameters of the two most popular models for simulating the migration of radionuclides in undisturbed soils have been compiled and evaluated statistically. Due to restrictions on the applicability of compartmental models, the convection–dispersion equation and its parameter values should be preferred. For radiocaesium, recommended values are derived for its effective convection velocity and dispersion coefficient. Data deficiencies still exist for radionuclides other than caesium and for soils of non-temperate environments.     

Incineration at Bayou Bonfouca Remediation Project

The Bayou Bonfouca hazardous waste site is located in Slidell, Louisiana, approximately 96 kilometers (60 miles) northeast of New Orleans. This site is ranked number 1,006 on the National Priorities List of Superfund sites. The U.S. Environmental Protection Agency (EPA) conducted a remedial investigation in 1986 and determined the primary potential exposure sources to be groundwater, surface waste piles, and contaminated sediment in Bayou Bonfouca. Based on the results of investigations, EPA and the Louisiana Department of Environmental Quality chose a remedy that involves dredging contaminated sediment from the bayou, excavating contaminated waste piles and soil, and incinerating the solid wastes in a transportable incinerator. The site remedy, which included incineration, was specified in the Record of Decision signed in March 1987.

Of the total 142,000 megagrams (Mg) (157,000 tons) of waste to be incinerated, approximately 119,000 Mg (132,000 tons) consist of hazardous sediment from the bayou; 22,600 Mg (25,000 tons) consist of lightly contaminated soils and waste piles, cellulosic materials, and other miscellaneous wastes on the ground. The solid wastes are primarily low heat content sediment and soils and cellulosic materials with polyaromatic hydrocarbon (PAH) concentrations from milligrams per kilogram (parts per million) levels up to two percent. The dredged bayou sediment will be dewatered in six, 115-cubiometer (150-cubic-yard) plate and frame filter presses before processing in the incinerator. A rotary-kiln-based single train incinerator is deployed at Bayou Bonfouca to process the solid waste feed.

On-site pilot studies indicated that the PAHs in groundwater could be removed by on-site pumping, treatment, and discharge of treated effluent to the bayou. The groundwater treatment plant went on-stream in June 1991. Treatment involves oil/water separation, filtration, carbon bed adsorption, and aeration.

IT Corporation-OH Materials, a joint venture, was awarded a contract in May 1991 and a notice to proceed in February 1992 to remediate and restore the Bayou Bonfouca site. The remediation project includes air quality monitoring and controls, site preparation, dredging and excavation, bayou bank stabilization and monitoring, equipment mobilization and erection, the trial burn, incineration, demobilization, and site closure. The project completed a successful trial burn in November 1993, and the commercial operation began in December 1993. The expected duration of the project is 40 months from mobilization to site closure.     

Common operations failure modes in the process industries

The Abnormal Situation Management^® (ASM^®) Consortium (This research study was sponsored by the Abnormal Situation Management (ASM) Consortium. ASM^® and Abnormal Situation Management^® are registered trademarks of Honeywell International, Inc.) funded a study to investigate common failure modes and root causes associated with operations practices. The study team analyzed 20 public and 12 private incident reports using the TapRoot^® methodology to identify root causes. These root causes were mapped to operations practice failures. This paper describes the top ten operations failure modes identified in the analysis. Specific recommendations include how to analyze plant incident reports to better understand the sources of systemic failures and improve plant operating practices.     

Potential of acid activated clays in the clarification of menhaden stickwater

Abstract

The primary objective of this investigation was to determine the feasibility of using acid activated clays to clarify menhaden stickwater effluent. Experiments, such as physical and chemical properties determinations, effect of changes in pH and temperature and coagulation, and coagulation followed by clay treatment were also performed to study the separation of solids in stickwater.

Analysis of the stickwater showed that it contained 4.5% crude protein, 1.4% crude fat, 6.5% total solids, 1.13% ash and 93.1% water. At a wavelength of 575 um, the sample absorbed all the light and the percent transmittance was zero. When diluted 1:100 the percent transmittance was 0.39 at the same wavelength. Measured at 25°C the sample had a viscosity of 9.0 centipoises.

The results showed that the precipitation of fat increased with increasing temperatures, while the reverse was true for protein. A pH of 4.0 gave the maximum clarification at all temperatures employed. The viscosity decreased at pH values above and below the original pH of the sample.

Among the four different acid activated clays used in this study (trade names Supact‐150, Impact‐150, Impact‐12 and Impact‐1OORR), Impact‐150 was the most effective in protein and fat precipitation, and the degree of separation of these components increased by treating stickwater with a coagulant (aluminum sulfate) prior to treatment with acid activated clay.