Effect of carbon tetrachloride on sonochemical decomposition of methyl orange in water

Two types of sonicators were used for the sonochemical decomposition of methyl orange (MO) in the presence and absence of carbon tetrachloride (CCl4): One is a 45kHz ultrasonic cleaning bath (a low intensity sonicator) and the other is a 200kHz ultrasonic reactor (a high intensity sonicator). It was clearly confirmed that the rates of the sonochemical decomposition of MO increased with increasing the concentration of CCl4 in both sonicators. The enhancement effect of CCl4 was much higher in the high intensity sonicator than in the low intensity one: by the addition of 100ppm of CCl4, the decomposition ratio of MO with the high intensity sonicator became 41 times larger, while that with the low intensity sonicator became 4.8 times larger. Based on the obtained results, it was suggested that the formed cavitation phenomenon was different between sonicators. It was also suggested that the sonochemical decomposition of MO in the presence of CCl4 would be useful to evaluate the sonochemical efficiency, because the rate of MO decomposition can be effectively enhanced by the sonolysis of CCl4.     

Changes in the flood regime of S?o Francisco River (Brazil) from 1940 to 2006

Flow regulation causes various environmental impacts in the downstream reaches of impounded rivers. The S?o Francisco River (SF) basin is Brazil’s third most important watershed. Several dams have been built in its course in the last four decades, mostly for flow regulation and hydropower generation. This paper presents an evaluation of historical changes in the flood regime. Three regions of the SF River basin, which are under the influence of different levels of regulation, were studied: the lower, middle, and upper SF River. The components of magnitude, frequency, and duration of floods were quantified for each region from 1940 to 1960 (prior to the construction of the first dam) and from 1986 to 2006 (after the last dam). The results have shown the inexistence of big floods in the downstream areas, decreasing durations of small floods as well as significant changes in the annual seasonality of floods. Reductions in the flood frequency were verified in all stretches, even in non-regulated systems, such as the lower Velhas River. The climate variation, which occurred in both period, was not able to explain the changes in the flood regime of S?o Francisco River; therefore, dams and other anthropogenic activity are the main factors promoting the temporal variability of streamflows in the S?o Francisco basin.     

Chelipeds are the real weapon: cheliped size is a more effective determinant than body size in male–male competition for mates in a hermit crab

To understand the evolution of weapons, we must understand both their functions and relative importance compared to body size in determining fighting success. Many decapod crustaceans develop disproportionately large chelipeds for their body size and use them as a weapon in agonistic interaction. There are, however, examples where weapons are merely signals of resource holding potential (RHP) and the RHP is actually determined by body size. We investigated the function and relative efficacy of body size and major cheliped size in male–male contests for females in the hermit crab Diogenes nitidimanus. Contests over females took two forms: (1) males preemptively guarded females and opponents did not fight with the guarding male. Cheliped size contributed significantly to the settlement of these contests and probably functioned as a visual signal for the opponents. (2) Guarding males engaged in physical combat with an opponent. In these cases, both body and cheliped sizes affected contest outcomes. The effect size for cheliped size was as strong, or stronger, than that for body size. These results suggest that large chelipeds have evolved as a true weapon and are effective in escalated fights for resources. Therefore they are also efficient visual signals for settling contests with only display. Our results are a rare example that clearly demonstrate that weapons are a more important determinant of fights than body size when both body and weapon size affect resource acquisition.     

Digestion performance and microbial community in full-scale methane fermentation of stillage from sweet potato-shochu production

Sweet potato shochu is a traditional Japanese spirit produced mainly in the South Kyushu area in Japan. The amount of stillage reaches approximately 8 × 105tons per year. Wastewater mainly containing stillage from the production of sweet potato-shochu was treated thermophilically in a fullscale treatment plant using fixed-bed reactors(8 reactors × 283 m3). Following the addition of Ni2+ and Co2+, the reactors have been stably operated for six years at a high chemical oxygen demand(COD) loading rate of 14 kg/(m3·day). Analysis of coenzyme content and microbial communities indicated that similar microbial communities were present in the liquid phase and on the fiber carriers installed in reactors. Bacteria in the phyla Firmicutes as well as Bacteroidetes were dominant bacteria, and Methanosarcina thermophila as well as Methanothermobacter crinale were dominant methanogens in the reactors. This study reveals that stillage from sweet potato-shochu production can be treated effectively in a full-scale fixed-bed reactor under thermophilic conditions with the help of Ni2+and Co2+. The high diversity of bacterial community and the coexistence of both aceticlastic and hydrogenotrophic methanogens contributed to the excellent fermentation performance.     

Aniline removal by Photocatalytic reaction of iron(iii) mediated with dissolved organic matter

When light (> 370 nm) was allowed to interact with an aqueous solution containing dissolved organic matter (DOM) and Fe(III), removal of aniline (AN) was observed. This was due to the photocatalytic reaction of Fe(III) mediated by DOM. Syringic acid (SYA) and humic acid (HA) were used as DOM in the present study. The ¹⁵N‐NMR spectrum of the product mixture from the light irradiation of the SYA/Fe(III) system demonstrated that AN was covalently bound to SYA. The kinetics of AN removal were, therefore, interpreted by assuming covalent binding between DOM and AN. The amounts of covalent binding sites and the apparent second‐order rate constants could be evaluated, and the amounts of covalent binding sites decreased with the increases of the concentration of DOM. This is attributed that the polymerization of DOM by the photo‐oxidation competed with the covalent binding between AN and DOM.     

The trail pheromone of the ant <Emphasis Type="Italic">Crematogaster castanea</Emphasis>

Summary. The major component of the trail pheromone of the myrmicine ant Crematogaster castanea has been identified as (R)-2-dodecanol from the tibial glands of the hind legs. The substance gave activity comparable to the contents of 8 tibial glands at a concentration of 1 pg per 32 cm trail.     

Local Circulation with Aeolian Dust on the Slopes and Foot Areas of the Tianshan and Kunlun Mountains around the Taklimakan Desert, China

Four automatic weather stations (AWS) were installed on the slopes and foot areas of the Tianshan and Kunlun Mountains along a longitude of 80 degrees east: (1) Taglak 2400 m a.s.l., (2) Aksu 1000 m, (3) Kartash 2800 m, and (4) Qira 1700 m. These two slopes face the Taklimakan Desert. Tagliak lies on the southern slope of Tianshan, and Kartash on the northern slope of Kunlun. The meteorological characteristics of the mountainous regions were investigated using surface data obtained during an intensive observation period (IOP) in spring 2002. It was found that visibility on the slopes decreases in the daytime, and there is no relationship between visibility and wind speed in the mountainous areas. Two snow layers containing dust particles were observed in the snow cover in Taglak during the IOP in spring 2003. These results suggest that a warm air parcel containing aeolian dust climbs over the slopes of the mountainous areas, and dust particles in the mountainous areas are transported from the foot areas.