Ordering of ruthenium cluster carbonyls in mesoporous silica     

W Zhou  JM Thomas  DS Shephard  BFG Johnson  D Ozkaya  T Maschmeyer  RG Bell  Q Ge 《Science (New York, N.Y.)》1998,280(5364):705-708

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.  相似文献   

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RG MARTIN 《Australian veterinary journal》1999,77(11):727-727

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Current status of cockle bed restoration in New Zealand     

Islay D. Marsden  Suzanne C. Adkins 《Aquaculture International》2010,18(1):83-97

The intertidal cockle Austrovenus stutchburyi, also known as tuangi or littleneck clam, is endemic to New Zealand, where it commonly occurs in sheltered sandflats and estuaries. While it is still abundant in some places, recreational collecting and habitat change have resulted in the losses of shellfish beds. This paper reviews the current status of cockle beds in New Zealand and outlines some of the methods that are being used to try to re-establish them. Cockle populations differ both within and between locations, and recent research suggests that this is often site-specific and correlated with sediment properties, salinity and contamination levels. The role of Customary Fishing Regulations and the management of Maori Marine Reserves in promoting cockles as a sustainable shellfishery is discussed, together with the role of closures. The transfer of adult stock may be the most promising technique for restoration. There is, however, a need to identify the potential risks and choose the sites carefully to ensure that shellfish are sustainable and that they improve ecosystem function.  相似文献   

The mobility of nitrification inhibitors under simulated ruminant urine deposition and rainfall: a comparison between DCD and DMPP     

Karina A. Marsden  Antonio J. Marín-Martínez  Antonio Vallejo  Paul W. Hill  Davey L. Jones  David R. Chadwick 《Biology and Fertility of Soils》2016,52(4):491-503

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Role of Fatty Acids in Energy Provision During Oocyte Maturation and Early Embryo Development     

RG Sturmey  A Reis  HJ Leese  TG McEvoy 《Reproduction in domestic animals》2009,44(S3):50-58

While much is known about the metabolism of exogenous nutrients such as glucose, lactate, pyruvate, amino acids by oocytes and pre-implantation mammalian embryos, the role of endogenous stores, particularly lipid, has been largely overlooked. The presence of lipid within oocytes and early embryos has been long known, and comparisons between species indicate that the amounts and types of lipid present vary considerably. Large amounts of intracellular lipid can compromise the success of cryopreservation and the removal of such lipid has been the subject of considerable effort. In this review, we present evidence that strongly suggests a metabolic role for lipid, specifically with regard to energy provision, in the late-stage oocyte and the pre-implantation embryo. We focus initially on oxygen consumption as a global indicator of metabolic activity, before reviewing different approaches that either have been designed to investigate directly, or have revealed indirectly the role of endogenous lipid in energy generation. These fall under five headings: (i) fatty acid oxidation; (ii) inhibition of triglyceride oxidation; (iii) culture in the absence of exogenous substrates; (iv) cytoplasmic organization; and (v) delipidation. On the basis of the data derived from these studies, we conclude that there is strong evidence for the utilization of endogenous lipid as an energy substrate by oocytes and early embryos.  相似文献   

Early Pregnancy Detection of Iraqi Riverine Buffalo (Bubalus bubalis) Using the BioPRYN Enzyme‐Linked Immunosorbent Assay for PSPB and the Progesterone Assay     

TA Abdulkareem  SAM Al‐Sharifi  MA Ishak  SM Eidan  MA Alnimr  CW Passavant  JR Branen  RG Sasser 《Reproduction in domestic animals》2011,46(3):455-462

This study was undertaken to detect pregnancy in Iraqi riverine buffalo (Bubalus bubalis) using three different methods (rectal palpation, plasma progesterone concentration and detection of the presence of pregnancy‐specific protein B (PSPB) with the BioPRYN^® enzyme‐linked immunosorbent assay (ELISA) test. The aim of the study was to identify the most sensitive, early and accurate method for detecting pregnancy. Twenty‐two female riverine buffalo that were 6.0 ± 0.93 years old were used. Four blood samples per buffalo were taken via jugular venipuncture at days 22–24, 32–34, 42–44 and 58–61 post‐mating (PM) to measure the progesterone concentration (ng/ml) and to detect the presence of plasma PSPB. The rectal palpation method was employed to evaluate all buffalo on days 42–44 and 58–61 PM. The BioPRYN^® test differed (p < 0.01) from the other tests with earlier accuracy for detecting pregnant and non‐pregnant buffalo. Eighty‐eight percent of pregnant and 76.9% of non‐pregnant buffalo were distinguished early (days 22–24 PM) using BioPRYN^® and plasma PSPB‐ELISA level (2.09 ± 0.12 ng/ml) in relation to 66.7% and 53.9% detected using the progesterone assay at similar days (4.30 ± 0.40 ng/ml). In conclusion, these results described, for the first time, the early and accurate pregnancy detection of water riverine buffalo using BioPRYN^® technology and provided the plasma levels of PSPB using an ELISA test. These findings will improve the reproductive and productive efficiency of Iraqi riverine buffalo by adapting the recent management and reproductive strategies in Iraq and in the world.  相似文献   

Fluxes of CO₂ above a plantation of Eucalyptus in southeast Brazil     

Osvaldo M.R. Cabral  John H.C. Gash  Humberto R. RochaClaire Marsden  Marcos A.V. LigoHelber C. Freitas  Jonatan D. TatschEduardo Gomes 《Agricultural and Forest Meteorology》2011,151(1):49-59

Eddy-covariance measurements of net ecosystem exchange of CO₂ (NEE) and estimates of gross ecosystem productivity (GEP) and ecosystem respiration (R_E) were obtained in a 2-4 year old Eucalyptus plantation during two years with very different winter rainfall. In the first (drier) year the annual NEE, GEP and R_E were lower than the sums in the second (normal) year, and conversely the total respiratory costs of assimilated carbon were higher in the dry year than in the normal year.Although the net primary production (NPP) in the first year was 23% lower than that of the second year, the decrease in the carbon use efficiency (CUE = NPP/GEP) was 11% and autotrophic respiration utilized more resources in the first, dry year than in the second, normal year. The time variations in NEE were followed by NPP, because in these young Eucalyptus plantations NEE is very largely dominated by NPP, and heterotrophic respiration plays only a relatively minor role.During the dry season a pronounced hysteresis was observed in the relationship between NEE and photosynthetically active radiation, and NEE fluxes were inversely proportional to humidity saturation deficit values greater than 0.8 kPa. Nighttime fluxes of CO₂ during calm conditions when the friction velocity (u_*) was below the threshold (0.25 m s⁻¹) were estimated based on a Q₁₀ temperature-dependence relationship adjusted separately for different classes of soil moisture content, which regulated the temperature sensitivity of ecosystem respiration.  相似文献   

Temporal Variation in Egg and Larval Productivity of Eyestalk Ablated Spawners of the Prawn Penaeus monodon from Cook Bay, Australia     

S. W. Hansford  G. E. Marsden 《Journal of the World Aquaculture Society》1995,26(4):396-405

This paper reports on the variability in spawner performance and viability of the eggs and larvae of Penueus monodon from a single geographical region (Cook Bay, Australia). Data is presented from seven separate experiments spawning eyestalk ablated P. monodon conducted between Sep tember 1992 and July 1994. These experiments used 200 spawners from which 290 spawns were assayed. Total egg and larval (Nauplius, and ha,) production values per prawn were calculated and were significantly different ( P < 0.05) between experiments. Spawner weight and number of spawns per prawn also varied significantly between experiments and, although these factors afiected egg and larval productivity, they accounted for only a small percentage of the observed variability. The cause of this variation is unknown but it may be due to differences in the age of the spawners and to seasonal environmental effects. The variation in reproductive success of wildcaught spawners probably reflects differences in overall condition of the spawners and/or their nutritional status at different times. Understanding the causes of variation in productivity is important if hatcheries are to improve the reliability of supply of larvae for the prawn farming industry.  相似文献   

Survival by sheep body lice (Bovicola ovis) after plunge dipping in synthetic pyrethroid lousicides   总被引：1，自引：0，他引：1  

RG KEYS  LA TOOHEY  TARUL THILAKAN 《Australian veterinary journal》1993,70(3):117-117

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Black soil blindness: A new mycotoxicosis of cattle grazing Corallocytostroma-infected Mitchell grass (Astrebla spp)     

TF JUBB  DC MAIN†  AA MITCHELL†  RG SHIVAS†  KW DE  WITTE‡ 《Australian veterinary journal》1996,73(2):49-51

A new, fatal mycotoxicosis of cattle has been recognised in north-western Australia. A feeding trial confirmed the toxicity of a previously unknown species of Corallocytostroma that grows on Mitchell grass (Astrebla spp). The disease has been colloquially named ‘black soil blindness’ because its most prominent features are its confinement to pastures on black soil, and blindness and death of affected animals. Over 500 cattle have died and considerable subclinical disease is present. Above average wet season rainfall and extended growing seasons may explain the emergence of the fungus. The disease is important because cattle production in large areas of Australia utilise Mitchell grass pastures.  相似文献