Ordering of ruthenium cluster carbonyls in mesoporous silica

The anionic ruthenium cluster carbonylates [Ru6C(CO)16]2- or [H2Ru10(CO)25]2- interspersed with bis(triphenylphosphino)iminium counterions (PPN+) are incorporated from solution into the pores of MCM-41 mesoporous silica (3 nanometers in diameter), where they form tightly packed arrays. These arrays were shown by high-resolution transmission electron microscopy, Fourier transform optical diffraction, and computer simulations to be well ordered both along and perpendicular to the axis of the cylindrical pores. In their denuded state produced by gentle thermolysis, the cluster carbonylates yield nanoparticles of ruthenium that are less well ordered than their assimilated precursors but show good activity as hydrogenation catalysts for hexene and cyclooctene. In both their as-prepared and denuded states, these encapsulated clusters are likely to exhibit interesting electronic and other properties.     

Near extinction of a large, widely distributed fish

Are extinctions of marine vertebrates as rare and unlikely as current data indicate? Long-term research surveys on the continental shelf between the Grand Banks of Newfoundland and southern New England reveal that one of the largest skates in the northwest Atlantic, the barndoor skate (Raja laevis), is close to extinction. Forty-five years ago, research surveys on St. Pierre Bank (off southern Newfoundland) recorded barndoor skates in 10% of their tows; in the last 20 years, none has been caught, and this pattern of decline is similar throughout the range of the species.     

Scrub-itch mite infestation in the endangered bridled nailtail wallaby

Skin lesions on the ears and inguinal and axillary regions of a number of adult animals within a captive population of the endangered bridled nailtail wallaby ( Onychogalea fraenata ) were associated with the trombiculid mite, Eutrombicula hirsti . The local inflammatory response of these Australian marsupials is described.     

Detection of water in the LCROSS ejecta plume

Several remote observations have indicated that water ice may be presented in permanently shadowed craters of the Moon. The Lunar Crater Observation and Sensing Satellite (LCROSS) mission was designed to provide direct evidence. On 9 October 2009, a spent Centaur rocket struck the persistently shadowed region within the lunar south pole crater Cabeus, ejecting debris, dust, and vapor. This material was observed by a second "shepherding" spacecraft, which carried nine instruments, including cameras, spectrometers, and a radiometer. Near-infrared absorbance attributed to water vapor and ice and ultraviolet emissions attributable to hydroxyl radicals support the presence of water in the debris. The maximum total water vapor and water ice within the instrument field of view was 155 ± 12 kilograms. Given the estimated total excavated mass of regolith that reached sunlight, and hence was observable, the concentration of water ice in the regolith at the LCROSS impact site is estimated to be 5.6 ± 2.9% by mass. In addition to water, spectral bands of a number of other volatile compounds were observed, including light hydrocarbons, sulfur-bearing species, and carbon dioxide.     

Optimum irrigation and pond operation to move away from exclusively rainfed agriculture: the Boru Dodota Spate Irrigation Scheme, Ethiopia

Under rainfed agriculture without supplementary supply, crop failure due to erratic rainfall has become a common phenomenon in many regions of Ethiopia. Spate irrigation development with storage provision at the 5,000 ha Boru Dodota Spate Irrigation Scheme is one of the initiatives to move away from exclusively rain-dependent agriculture. This initiative has faced several challenges. Lack of design experience and failure to fully grasp the unpredictable nature of the spate flow caused the Boru Dodota Spate Irrigation Scheme to be implemented without considering the necessity of storage ponds. In addition, absence of a systematic approach to assist planners has resulted in non-optimal design of ponds’ capacity and operation. The study, on which this article is based, aimed at optimum storage operation to irrigate the maximum possible area with the existing ponds’ capacity and available water resource. During the study, the surface storage and irrigation scheme planning model was developed and used to analyze several pond operation scenarios in Boru Dodota Spate Irrigation Scheme. The main findings were as follows: (1) Supplementing the rainfall with the operation of the existing 19 ponds that enable weekly irrigation frequency results in irrigating at least 6,600 ha. (2) An increase in the number of ponds does not always guarantee an increase in the size of irrigated land because the water resources, the operation, and management are defining factors. (3) It is not economical to only rely on spate flow for irrigation as even with 200 ponds, a maximum of 1,250 ha could be irrigated.