Removal of mercury using processes involving sulfuric acid during zinc production in an imperial smelting process (ISP) plant

Journal of Material Cycles and Waste Management - Mercury emissions from non-ferrous metal industries are a major environmental concern. Because of the large differences in mercury emission factors...     

A consideration for using workers’ heuristics to improve safety rules based on relationships between creative mental sets and rule-violating actions

This paper reports on the relationships between creative mental sets and rule-violating actions using questionnaires answered by 218 nursing workers. An exploratory factor analysis was conducted. The results revealed five factors of creative mental sets: curiosity, minutiae, inquiry, sensitivity, and courage. In addition, rule-violating actions were found to consist of three factors: violation of regulations, violation of local rules, and self-style. The results of multiple regression analyses showed a negative relation between curiosity and regular rule violation. Negative correlations were observed among minutiae, inquiry, and local rule violation. Furthermore, the mean score of local rule violation of a person who thinks that it is important for the work environment to offer high and excellent care is significantly higher than that of those who think that other environmental considerations are more important. The result elucidated the necessity of using workers’ heuristics in the process of improving safety rules as well as improving their acceptability to workers. This point is important and applicable not only in the field of patient safety management systems, but also in other fields.     

Maximal yields from multispecies fisheries systems: rules for systems with multiple trophic levels.

Increasing centralization of the control of fisheries combined with increased knowledge of food-web relationships is likely to lead to attempts to maximize economic yield from entire food webs. With the exception of predator-prey systems, we lack any analysis of the nature of such yield-maximizing strategies. We use simple food-web models to investigate the nature of yield- or profit-maximizing exploitation of communities including two types of three-species food webs and a variety of six-species systems with as many as five trophic levels. These models show that, for most webs, relatively few species are harvested at equilibrium and that a significant fraction of the species is lost from the web. These extinctions occur for two reasons: (1) indirect effects due to harvesting of species that had positive effects on the extinct species, and (2) intentional eradication of species that are not themselves valuable, but have negative effects on more valuable species. In most cases, the yield-maximizing harvest involves taking only species from one trophic level. In no case was an unharvested top predator part of the yield-maximizing strategy. Analyses reveal that the existence of direct density dependence in consumers has a large effect on the nature of the optimal harvest policy, typically resulting in harvest of a larger number of species. A constraint that all species must be retained in the system (a "constraint of biodiversity conservation") usually increases the number of species and trophic levels harvested at the yield-maximizing policy. The reduction in total yield caused by such a constraint is modest for most food webs but can be over 90% in some cases. Independent harvesting of species within the web can also cause extinctions but is less likely to do so.     

Carbonization of johkasou sludge using batch-type equipment

The carbonization of dehydrated johkasou sludge was examined using batch-type equipment. Based on the temperature changes in the carbonization room and the gas combustion room, the carbonization process was divided into three phases: phase I, drying the sludge; phase II, thermal decomposition of the dried sludge; phase III, after phase II. The times required for phases I and II were strongly correlated with the amounts of water and solid matter, respectively, in dehydrated sludge. The reduction rate of the sludge on completion of phase I was about 90% on average, and the decomposition rate of solid matter increased with time during phase II or phase II plus phase III until it reached about 50%. TOC concentration of the eluate from the carbonized sludge was used as an index to evaluate the progress of the carbonization process, and the highest temperature in the carbonization room was recognized as an important operational factor. The specific surface area and pore volume of carbonized sludge were smaller than those of charcoals and activated carbons by 1–3 orders of magnitude and 1–2 orders of magnitude, respectively. No elution of heavy metals was observed from any of the carbonized sludges examined. The reduced amount of carbon in dehydrated johkasou sludge was estimated to be about 25% of the decomposed organic matter.     

Global pollution monitoring of polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs) and coplanar polychlorinated biphenyls (coplanar PCBs) using skipjack tuna as bioindicator

In order to elucidate the global distribution of dioxins and related compounds, such as PCDDs, PCDFs and coplanar PCBs, levels of these compounds were determined in the muscle of skipjack tuna (Katsuwonus pelamis) collected from the offshore waters and open seas near Japan, Taiwan, Philippines, Indonesia, Seychelles and Brazil, and the Japan Sea, the East China Sea, the South China Sea, the Indian Ocean and the North Pacific Ocean. PCDDs, PCDFs and coplanar PCBs were detected in almost all the specimens collected from all the locations surveyed, indicating widespread contamination by these compounds in the marine environment. Higher concentrations of dioxins and coplanar PCBs were detected in the samples from temperate Asian regions, plausibly due to larger usage and anthropogenic generation in highly industrialized countries around the East China Sea and the South China Sea, such as Japan, Korea, Taiwan, Hong Kong and coastal China.     

Social system and reproduction of helpers in a cooperatively breeding cichlid fish (Julidochromis ornatus) in Lake Tanganyika: field observations and parentage analyses

It is suggested that some fish of the genus Julidochromis, substrate-brooding Tanganyikan cichlids with biparental care, breed cooperatively with helpers. We studied the social system of J. ornatus in the wild and analysed genetic parentage using microsatellites. Within the studied population three patterns of social system were identified: monogamous pairs (61%, 44 of 72 groups), pairs with helpers (29%, 21), and polygamous harems with helpers (controlled by either a large female or large male owner; 10%, 7). In cooperatively breeding groups, the number of helpers at each nest ranged from 1 to 6 (median 1), and male helpers were more numerous than female helpers. In both sexes, the body size was different among individuals of different social status (harem owner > breeder > helper). Helpers and harem owners of both sexes exhibited brood defence although its frequency was low. The molecular analysis revealed that (1) the helpers were mostly unrelated to dominant breeders, (2) many helpers of both sexes contributed genetically to the next generations, (3) male helpers had high siring success (41% of young in total), and (4) large young unrelated to group members were detected at 30% of observed nests, which may be due to breeder (or helper) replacements and immigration of young. We discuss the implications of these results for understanding the complex social system of this species, especially the low reproductive skew in comparison with other cooperatively breeding cichlids.     

Earlier rice phenology as a result of climate change can increase the risk of cold damage during reproductive growth in northern Japan

The present study analyzed the impact of earlier rice phenology as a result of climate change on the risk of cold damage during reproductive growth using the historical temperature record from 1961 to 2010 at four locations in northern Japan. During this period, heading date has become 0.7-1.9 days earlier per 10 years. Air temperatures during the booting stage (6-15 days before heading) decreased by 0.18 °C per 10 years even though the air temperature on a given calendar date has increased slightly. The estimated potential yield losses caused by cold damage have increased since the start of the study period. Thus, the advance in phonological events as a result of global warming is likely to increase the risk of future yield losses, and this has important implications for future adaptation strategies (breeding new cultivars and changing crop management strategies) to reduce the risk of cold damage.     

Voltammetric response of ferroceneboronic acid to diol and phenolic compounds as possible pollutants

A voltammetric determination of possible organic pollutants such as diol and phenolic compounds in water was studied using ferroceneboronic acid (FBA) as a redox-active marker. A cyclic voltammogram of FBA exhibited a pair of oxidation and reduction peaks at 230 and 170 mV at pH 7.0, respectively, while another pair of redox peaks was observed in the presence of diol or phenolic compounds tested. The results were rationalized based on the formation of boronate esters of FBA with the added compounds. The changes in the redox peak currents were dependent on the concentration of the additives, suggesting a usefulness of FBA in the electrochemical determination of these compounds in water.     

Procurement of exogenous ammonia by the swallowtail butterfly, Papilio polytes, for protein biosynthesis and sperm production

How to acquire sufficient quantity of nitrogen is a pivotal issue for herbivores, particularly for lepidopterans (butterflies and moths) of which diet quality greatly differs among their life stages. Male Lepidoptera often feed from mud puddles, dung, and carrion, a behavior known as puddling, which is thought to be supplementary feeding targeted chiefly at sodium. During copulation, males transfer a spermatophore to females that contains, besides sperm, nutrients (nuptial gifts) rich in sodium, proteins, and amino acids. However, it is still poorly understood how adults, mostly nectarivores, extract nitrogen from the environment. We examined the availability of two ubiquitous inorganic nitrogenous ions in nature, viz. ammonium (or ammonia) and nitrate ions, as nutrients in a butterfly, and show that exogenous ammonia ingested by adult males of the swallowtail, Papilio polytes, can serve as a resource for protein biosynthesis. Feeding experiments with ¹⁵N-labeled ammonium chloride revealed that nitrogen was incorporated into eupyrene spermatozoa, seminal protein, and thoracic muscle. Ammonia uptake by males significantly increased the number of eupyrene sperms in the reproductive tract tissues. The females also had the capacity to assimilate ammonia into egg protein. Consequently, it is evident that acquired ammonia is utilized for the replenishment of proteins allocable for reproduction and somatic maintenance. The active exploitation of exogenous ammonia as a nutrient by a butterfly would foster better understanding of the foraging and reproductive strategies in insects.