Sleeping respiratory rates in apparently healthy adult dogs

Respiratory rate monitoring of cardiac patients is recommended by many cardiologists. However, little objective data exist about respiratory rates in apparently healthy dogs when collected in the home environment. We measured sleeping respiratory rates (SRR) in apparently healthy dogs and compared sleeping and resting respiratory rates (RRR) with a cross-sectional prospective study. Participants collected 12-14 one-minute SRR over a period ranging from 1 week to 2 months on 114 privately owned adult dogs. Selected participants simultaneously collected RRR. Mean within-dog average SRR (SRR(mean)) was 13breaths per minute (breaths/min). No dog had SRR(mean) >23 breaths/min; three dogs had instantaneous SRR measurements >30 breaths/min. Dogs had higher RRR(mean) (19 breaths/min) than SRR(mean) (15 breaths/min) (P<0.05). Canine SRR(mean) was unaffected by age, bodyweight or geographic location. Data acquisition was considered relatively simple by most participants. This study shows that apparently healthy adult dogs generally have SRR(mean) <30 breaths/min and rarely exceed this rate at any time.     

Discovery,characterization and exploitation of Mlo powdery mildew resistance in barley

Summary Mlo resistance to barley powdery mildew is a relatively new kind of resistance. It was originally described in a powdery mildew resistant barley mutant in 1942 and has been mutagen-induced repeatedly since then. About 1970 it was also recognized in barley landraces collected in Ethiopia in the 1930s. It is unique in that 1) Mlo resistance does not conform to the gene-for-gene system; 2)mlo genes originating from different mutational events map as non-complementing recessive alleles in one locus; 3) all alleles confer the same phenotype, though with small quantitative differences; 4) it is effective against all isolates of the pathogen; and 5) the resistance is caused by rapid formation of large cell wall appositions at the encounter sites preventing penetration by the fungus. Powdery mildew isolates with elevated Mlo aggressiveness have been produced on barley in the laboratory, but have not been found in nature. Mlo resistance is considered very durable. The exploitation of Mlo resistance has been hampered by pleiotropic effects of themlo genes, vix. necrotic leaf spotting and reduced grain yield, but they have been overcome by recent breeding work. During the 1980s Mlo-resistant spring barley varieties have become cultivated extensively in several European countries, in 1990 on about 700,000 ha.     

Seed Yield Stability of Okra as Influenced by Planting Date

Fifteen selected okra varieties consisting of ten newly-developed lines and five established varieties were evaluated for stability of seed yields in eight different environments i.e. several monthly plantings for three consecutive years. Seed yield data were analyzed to determine the effectiveness of using different planting dates in seed yield trials of new okra varieties. The wide ranges of environmental indices (- 10.8 to 24.4) and seed yield (2.7 to 38.0 g plant ^-1) indicated significant variation between the environments even though the trials were conducted at the same location. A regression method of stability analysis showed that the mean differences between environments, the varieties and their interactions were highly significant. These results suggest that where limited resources prevent the use of several locations, different dates of planting for two or more years could be used to evaluate okra varieties for seed yield without losing much information on their relative ranking.     

The potential of integrated marketing in increasing adoption of land rehabilitation practices in northwest New South Wales,Australia

Land degradation is a major threat to the productivity of agricultural land in Australia, and on the soils used for growing wheat (Triticum aestivum) soil erosion and fertility decline are serious problems. A study financed jointly by NSW Agriculture, Grains Research and Development Corporation (GRDC) and agribusiness looked at the effectiveness of using integrated marketing to increase adoption of dryland lucerne (Medicago sativa) in rotations in northwestern NSW as a means to rehabilitate degraded wheat soils. At the time of the study, average wheat and protein yields were declining. Integrated marketing, with heavy reliance on television advertising, was run during Summer 1992 and Autumn 1993. Approximately 750 wheat growers, located around Moree in NSW comprised the target group. A similar number of comparable farmers from around Dalby in southern Queensland, who were not exposed to the promotional campaign, formed the control group. Farmers were surveyed by mail just before and 18 months after the campaign. While the results were compounded by severe drought during the study time, as well as by other constraints, the data suggest none the less the value of this approach in getting farmers to change their practices. One in six wheat growers in the target area were aware of the free information kit available via the advertised 1800 number or freepost mail coupon; one in twelve obtained the kit. Television was the most influential media in eliciting a response, followed by the Australian Grain Magazine. The results suggested that the campaign did in fact engender the desired change. The study highlights the possible role integrated marketing may play in rural Australia, whether the subject dealt with is agricultural, environmental or other, not because of any novelty value, but because of the technique itself. © 1998 John Wiley & Sons, Ltd.     

Determination of transpiration in irrigated grapevines: comparison of the heat-pulse technique with gravimetric and micrometeorological methods

The use of a heat-pulse technique to monitor sap flow from which transpiration can be deduced was evaluated in ungrafted grapevines (Vitis vinifera L., cv. Sultana) under glasshouse and field conditions. There was a significant degree of agreement between daily transpiration deduced from heat-pulse velocity (T _hp) and that determined directly by gravimetry in the glasshouse and by calibration using the Penman-Monteith equation in the field. Comparison throughout the growing season of T _hp to transpiration calculated with the full Penman-Monteith equation produced a high coefficient of determination (r ²=0.69). A similar comparison of T _hp with transpiration calculated with only the aerodynamic component of the Penman-Monteith equation produced a non-linear relationship, due to the equation over-estimating transpiration relative to T _hp at high vapour pressure deficits (i.e. above 2.5 kPa). Values for total seasonal transpiration measured with heat-pulse sensors or calculated with either the full Penman-Monteith equation or with only the modified aerodynamic component of the equation were within 10% of each other. Transpiration (T _hp) in grapevines with an adequate supply of soil water was shown to be coupled to ambient air conditions. Received: 20 July 1998     

Effective nitrification inhibitors may improve fertilizer recovery in irrigated cotton

N fertilizer is often poorly recovered in irrigated cotton production, due to N loss through denitrification. We researched the ability of inhibitors to delay nitrition and reduce the availability of NO₃ ^- to denitrifying microorganisms and thus improve N fertilizer recovery, 2-Ethynylpyridine, etridiazole, and nitrapyrin proved highly effective nitrification inhibitors, although nitrification was evident several weeks after their application. CaC₂ was relatively ineffective, even when wax-coated to prolong the evolution of C₂H₂. Phenylacetylene and ethynylcyclohexanol were also ineffective, despite having a chemical structure similar to 2-ethynylpyridine. A strong association was identified between each compound's ability to inhibit nitrification and its capacity to improve N fertilizer recovery. In one experiment, N fertilizer recovery was increased by 50% with 2-ethynylpyridine, etridiazole, or nitrapyrin application, from 33% without inhibitors. The inhibitors had little effect on fertilizer recovery where N losses were relatively small. 3-Methyl pyrazole significantly increased N uptake and lint yield, but the nitrification inhibitors had no significant effect on N uptake or on yield in two of the three of the cotton crops. A laboratory study confirmed that nitrification inhibitor effectiveness declined in the order 2-ethynylpyridine>etridiazole>nitrapyrin>3-methyl pyrazole>phenylacetylene>CaC₂>ethynylcyclohexanolThis research was conducted at Australian Cotton Research Institute, CSIRO Division of Plant Industry, Locked Bag 59, Narrabri, NSW 2390, Australia