Feasibility study of a passive aeration reactor equipped with vertical pipes for compost stabilization of cow manure.

Pilot-scale composting was carried out with cow manure to evaluate the performances of two passive aeration systems: a conventional passive aeration system equipped with horizontal pipes and an unusual passive aeration method based on air delivery by means of vertical pipes. The effects of both types of passive aeration apparatus were investigated in order to determine the degree of composting rate by continuously monitoring temperature, moisture content, organic matter, electrical conductivity, pH and C/N ratio in the piles. Temperatures in the range of thermophily (55-65 degrees C) were reached in all runs within 1-2 days then lasting for about 1 week, a span long enough for pathogen abatement. Results suggest that passive aeration carried out by vertical pipes is more effective for air delivery into compost piles than conventional passive aeration of air adduction with horizontal pipes. The variation in the number of vertical pipes was revealed to be an important parameter for the control of composting rate and temperature. Composting rates estimated from the heat balance equation were substantially in agreement with those computed through the conversion ratio of total organic matter decrement. The conversion ratios and composting rates obtained in this study using passive aeration with vertical pipes were well aligned with those found using forced air delivery systems.     

Effect of dietary protein on the distribution of cadmium,zinc and copper in rats following the oral administration of cadmium

Cadmium, 100 μg/rat/day, was administered orally 100 times (total amount of Cd administered, 10 mg), under conditions of low protein intake. The total amount of Cd in the liver and kidneys was as follows: females fed 20% protein diets > females fed 5% protein diets > males fed 20% protein diets ≒ males fed 5% protein diets. A decreased Zn concentration was found in the liver of males and the pancreas of males and females fed with the 5% protein diet. The Cu concentration in the kidneys was markedly influenced by low protein intake.     

The chemical basis for trail recognition in Lasius nipponensis (Hymenoptera: Formicidae)

Summary. In this paper we report on the chemical basis for trail recognition in Lasius nipponensis. On and near trails in the field, workers became aggressive against conspecific intruders and succeeded in protective contests, while intruders usually avoided confrontation. Such asymmetric interactions were also observed in the laboratory when two non-nestmate workers were sequentially placed in a clean glass dish, while mutual aggression was observed when they were placed simultaneously. Asymmetric aggression was also observed when the workers were placed in a dish previously conditioned by other workers, or when the dish was treated with the hexane rinse of the conditioned dish. The rinse contained a series of hydrocarbons, in which components and proportion were almost identical to those of the cuticular hydrocarbons of the workers, except for a lack of n-alkanes. Amounts of the hydrocarbons that remained on the dish were very small when all the tarsi of the workers were incapacitated. We therefore consider that the hydrocarbons are not adhesion of the cuticular hydrocarbons but secretion from the tarsi of workers, and serve as a key signal for trail recognition in this ant.     

Reproductive effects and bioconcentration of 4-nonylphenol in medaka fish (Oryzias latipes)

The objective of this study was to investigate the reproductive success (fertility and fecundity) of medaka (Oryzias latipes) exposed to 4-nonylphenol (4-NP) in water and the viability of their F(1) offspring. In addition, we measured the bioconcentration of 4-NP in eggs. After a 21-d exposure to 100microg/l 4-NP, medaka showed reduced egg production and fertility. Hepatic vitellogenin levels were increased significantly in males treated with 10, 50 and 100microg/l of 4-NP. In the F(1) generations, the hatchability and time to hatching of embryos in the 100microg/l treatment group were adversely affected, and 2-7microg 4-NP/g egg was found in spawned eggs (the bioconcentration factor: 30-100). These results indicate that (1) 4-NP adversely affected the reproduction (fecundity and fertility) of adult medaka, (2) 4-NP accumulated in eggs through maternal transfer and (3) these levels of 4-NP were associated with adverse effects in the F(1) offspring.     

Mate availability accelerates male filial cannibalism in a nest brooding fish: effects of number and fecundity of females

Theoretical models predict that increased mate availability accelerates filial cannibalism by the parental male, but we do not yet fully understand how the various aspects of mate availability contribute to this effect. We examined the effects of two elements of mate availability—female fecundity and sex ratio—on filial cannibalism by the lizard goby, Rhinogobius flumineus, which is a paternal nest brooding fish. We used three types of females (stimulus-females): a single female with slim belly (not ready to spawn), a single gravid female (ready to spawn), and two gravid females. Stimulus-females were housed in a transparent cage and shown to subject males just before and after spawning with a separate female, after which males cared for the brood. A single gravid stimulus-female accelerated filial cannibalism, compared with a control-stimulus consisting of an empty cage, but only during the early care period. In contrast, a single slim-bellied stimulus-female did not accelerate cannibalism. A stimulus of two gravid females accelerated cannibalism to the same degree as a single gravid female stimulus. Our results suggest that in lizard gobies, filial cannibalism by parental males is accelerated by female quality (fecundity) in the early care period, but not by a higher number of available females (sex ratio).     

Coadaptive changes in physiological and biophysical traits related to thermal stress in web spiders

Web spiders are considered to have expanded their habitats from dim to bright environments during the evolutionary history. Because they are sedentary predators exposed to the sun, they may have developed a suite of adaptive traits to cope with thermal stress. We examined the critical thermal maximum, spectral reflectance of solar energy by the body surface, and surface–volume ratio (SVR) for 11 spider species. Analysis of the four genera having a pair of species inhabiting both bright and dim environments showed that species in bright environments exhibited higher lethal temperatures, but spectral reflectance and SVR did not differ. Independent contrasts using the 11 species indicated that critical thermal maximum was positively correlated with spectral reflectance and spectral reflectance was negatively correlated with SVR. These results suggest that physiological tolerance to high temperatures and a biophysical mechanism to reduce heat gain evolved jointly during the history of habitat expansion in araneoid spiders.     

Soil functional responses to excess nitrogen inputs at global scale

There is little evidence that nitrogen (N) cycling in the highly weathered, low-phosphorus (P), acidic soils found in Southern Hemisphere continents will differ greatly from that in North America and Europe. Evidence from the 'south' shows: the similarity in forms and temporal patterns in losses of N from different land uses; that the C:N ratios of the forest floor/litter layer from different continents are strongly predictive of a range of processes on a global scale; that generalizations based on Northern Hemisphere experience of the impact of N additions to 'P-limited' ecosystems are likely to fail for southern ecosystems where anatomical and physiological adaptation of native plants to low-P soils makes questionable the concept of 'P-limitation'; that the greatest threats in the 'south' are probably changes in land use that may greatly increase N inputs and turnover; that localized increases in N inputs produce similar effects to those seen in the 'north'.     

Photocatalytic mineralization of hydroperfluorocarboxylic acids with heteropolyacid H₄SiW₁₂O₄₀ in water

The decomposition of hydroperfluorocarboxylic acids [H-PFCAs; HC_nF_2nCOOH (n = 4 and 6)] induced by heteropolyacid photocatalyst H₄SiW₁₂O₄₀ in water was investigated, and the results are compared with the results for the corresponding perfluorocarboxylic acids (PFCAs; C_nF_2n+1COOH). This is the first report on the photochemical decomposition of H-PFCAs, which are being developed as alternative surfactants to environmentally persistent and bioaccumulative PFCAs. H-PFCAs were not decomposed by irradiation with UV-Visible light (>290 nm) in the absence of H₄SiW₁₂O₄₀. In contrast, UV-Visible light irradiation of H-PFCAs in the presence of H₄SiW₁₂O₄₀ efficiently decomposed H-PFCAs to F⁻ and CO₂. The decomposition reactions showed pseudo-first-order kinetics, and the decomposition rate constants were 1.8-2.5 times higher than those for the corresponding PFCAs. The reaction mechanism can be explained by elimination of H⁺ from the ω-H atom of the H-PFCAs by the excited catalyst, followed by formation of perfluorodicarboxylic acids.