Sum rules and interlayer conductivity of high-Tc cuprates

Analysis of the interlayer infrared conductivity of cuprate high-transition temperature superconductors reveals an anomalously large energy scale extending up to midinfrared frequencies that can be attributed to formation of the superconducting condensate. This unusual effect is observed in a va- riety of materials, including Tl2Ba2CuO6+x, La2-xSrxCuO4, and YBa2Cu3O6.6, which show an incoherent interlayer response in the normal state. Midinfrared range condensation was examined in the context of sum rules that can be formulated for the complex conductivity. One possible interpretation of these experiments is in terms of a kinetic energy change associated with the superconducting transition.     

Cinnamamide,an avian repellent,reduces woodpigeon damage to oilseed rape

Woodpigeons Columba palumbus cause significant damage to oilseed rape Brassica napus. (Cruciferae) in Britain, especially between January and March. The potential of cinnamamide, a non-lethal chemical repellent, to protect growing oilseed rape from woodpigeon damage was assessed in 20×20 m plots laid out in a 9-ha field frequented by >500 woodpigeons. Despite a low initial loading of cinnamamide and low persistence of the compound after spraying, the inner leaves of treated plants received less damage than the inner leaves of untreated plants (P<0·05). This was reflected later in the trial in a decline in damage to the outer leaves of treated plants (P<0·05). No signs of phytotoxicity were seen on treated leaves during the trial. Cinnamamide did not completely protect the rape, and some plants in treated plots received considerable damage. This was probably due to the compound's poor persistence on the leaf and because it was applied late in the growing season (late February) when birds had already made inroads into the crop. © 1998 SCI.     

In from the cold: prospects for conversion of the defense industrial base

At the end of the Cold War, the manufacturing operations involved in making military equipment and commercial goods are commonly believed to intersect hardly at all. Our analyses of 1991 survey data from a large sample of establishments in the machining-intensive durable goods sector show that there are few technical and competitive conditions separating the defense and commercial industrial spheres. Commercial-military integration of production is now the normal practice among the majority of defense contractors in this sector. Moreover, we find little difference between defense and commercial producers in the competitive conditions they face or in the diversity of their customers. However, defense contractors have an advantage over their strictly commercial counterparts because of their greater use of productivity-enhancing technologies.     

Deep-sea erosion and manganese nodule development in the southeast Indian ocean

Features exhibited by a large number of sea floor photographs together with the dating of 187 sediment cores from the southeast Indian Ocean have revealed extensive manganese nodule development and sediment erosion in deep basinal areas. The most extensive nodule field, with an area of 10(6) square kilometers, occurs in the northwestern sector of the South Australian Basin and is named the Southeast Indian Ocean Manganese Pavement. The crests and flanks of the adjacent mid-ocean ridge are, in contrast, free of nodules and marked by much less dynamic bottom water conditions.     

Photolysis of dichlofluanid

Dichlofluanid was found to be degraded by ultraviolet light in methanol, benzene and acetone solution. The products from acetone solution included N,N-dimethyl-N′-phenylsulphamide, phenyl isocyanate, phenyl isothiocyanate and dimethylamidosulphonyl chloride. G.c.-m.s. studies further indicated the presence of bis(dichlorofluoromethyl) disulphide, 1-(dichlorofluoromethylthio)propan-2-one and 1-(dichlorofluoromethylsulphonyl)propan-2-one. In-vitro tests against Botrytis cinerea showed that irradiation decreased the activity of dichlofluanid and that synergism did not occur.     

Chlamydial infection in a colony of captive koalas

Forty three koalas in a captive colony were investigated for the presence of Chlamydia psittaci infection and associated disease. Swabs were taken from conjunctivae and urogenital sites for cell culture isolation of C psittaci and for cytological examination (direct smears) for chlamydial inclusions and evidence of inflammation. On the basis of cell culture isolation, 28 samples from 25 koalas were positive for C psittaci (that is, infected). Three koalas were positive from both sites, 5 from conjunctivae alone and 17 from urogenital sites alone. Seven of the 8 koalas with positive conjunctival swabs had overt signs of conjunctivitis, but only 3 of the 20 koalas with positive urogenital swabs had overt signs of 'wet bottom' (continual urine soiling due to cystitis) or purulent discharge. However, 5 of the 20 with positive urogenital swabs had past episodes of 'wet bottom'. Moreover, examination of direct cytological smears showed evidence of inflammation (neutrophils) in 7 of 8 koalas with positive conjunctival swabs and 17 of 20 with positive urogenital swabs. Chlamydial inclusions were rarely identified with surety on direct cytological smears. In the 18 koalas without chlamydia, one had overt conjunctivitis while 2 had past episodes of conjunctivitis. The koala with conjunctivitis at the time of sampling had a prior history of 'wet bottom'. Examination of direct cytological smears revealed 2 of the chlamydial negative koalas had high numbers of neutrophils in urogenital smears. It was concluded that C psittaci infection may cause overt or sub-clinical disease, with the former developing when the koalas were stressed through management procedures or concomitant disease.     

1,3,5-Triazapenta-1,4-dienes: Chemical aspects of a new group of pesticides

1,3,5-Triazapenta-1,4-dienes of formula Ar? N?CH? N(R)? CH?N? Ar′, are a new group of biologically active compounds. Various general methods for their preparation are described and their physical and chemical properties, including stability over range of pHs, are discussed. The unsymmetrical 1,3,5-triaza-penta-1,4-dienes(Ar≠Ar′) are unstable; insolution, particularly, they equilibrate to the corresponding stable symmetrical analogues. Structure-activity relationships in laboratory tests against Boophilus microplus and Tetranychus urticae are discussed. Problems in the synthesis of ring-[¹⁴C]-amitraz,^b [1,5-di-(2,4-dimethylphenyl)-3-methyl-1,3,5-triazapenta-l,4-diene], an active member of the group, are outlined.     

A large scale mastitis control programme in Somerset.

The results of a mastitis control programme operated in south west England for three years are given. Farmers participating in the full mastitis control group agreed to treat each cow at drying off with 500 mg benzathine cloxacillin in each quarter, to have their milking machines tested and to correct any faults, and to practise teat dipping. Data covering cell counts, milk production, milk quality and clinical mastitis, were assessed from herds taking part in the programme. Cell counts were analysed from all 507 herds taking part in the programme. Milk production records for the full mastitis control group (188 herds) over a three year period are discussed, and these results compared with milk production figures from Milk Marketing Board records from herds in the south west of England which were carrying out no specific mastitis control programme. The milk quality data compare the findings in 159 herds in the full mastitis control programme with those in 247 herds in the partial and no mastitis control groups. Cases of clinical mastitis during the three year period were recorded in 73 herds in the full mastitis control group. The problems of applying the control routines are presented with observations on clinical mastitis, bulk milk cell count, milk production and milk quality. After three years, herds in the programme had on average increased milk production by 75 gallons a cow, achieved a 14.6 per cent reduction in the incidence of clinical mastitis, and improved the milk total solids percentage by one milk quality payment class.