The potential of mini-ridging for controlling intrarow weeds: estimating minimum lethal burial depth

Weed management using synthetic herbicides is undergoing a global decline, necessitating a re-evaluation of existing control measures and the development of novel weed management tools. ‘Mini-ridging’ is a non-discriminatory, physical weeding method that functions by burying weeds in the intrarow with a laterally shifted ridge of soil. In glasshouse trials using potted plants, we found that plant recovery after soil application was influenced by plant size, which in turn was influenced by plant species, developmental stage and/or age. The likelihood of plant recovery after soil application was negatively related to the depth of soil applied: very few plants survived total coverage by soil but, conversely, survival could be substantial if some parts of the plants were not covered. The results suggest that burial under a depth of 6 cm of soil would eliminate most plants regardless of species or growth stage. Larger plants would require the application of a greater total depth of soil to achieve this 6 cm of soil cover, and weed management would, therefore, tend to be more successful and more practical if weeds were targeted when still small. This research demonstrates the potential of plant burial as a simple and reliable means of non-chemical weed management, and re-emphasises that, for weed control to be effective, the applied soil layer must cover the whole plant.     

Evaluation of brief dietary questions to estimate vegetable and fruit consumption - using serum carotenoids and red-cell folate

OBJECTIVE: To evaluate responses to self-administered brief questions regarding consumption of vegetables and fruit by comparison with blood levels of serum carotenoids and red-cell folate. DESIGN: A cross-sectional study in which participants reported their usual intake of fruit and vegetables in servings per day, and serum levels of five carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin and lycopene) and red-cell folate were measured. Serum carotenoid levels were determined by high-performance liquid chromatography, and red-cell folate by an automated immunoassay system. SETTINGS AND SUBJECTS: Between October and December 2000, a sample of 1598 adults aged 25 years and over, from six randomly selected urban centres in Queensland, Australia, were examined as part of a national study conducted to determine the prevalence of diabetes and associated cardiovascular risk factors. RESULTS: Statistically significant (P<0.01) associations with vegetable and fruit intake (categorised into groups: /=4 servings per day) were observed for alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin and red-cell folate. The mean level of these carotenoids and of red-cell folate increased with increasing frequency of reported servings of vegetables and fruit, both before and after adjusting for potential confounding factors. A significant association with lycopene was observed only for vegetable intake before adjusting for confounders. CONCLUSIONS: These data indicate that brief questions may be a simple and valuable tool for monitoring vegetable and fruit intake in this population.     

Chlamydia infection in cats in New Zealand

Conjunctival swabs collected in 1991-92 from 333 pedigree and non-pedigree cats were tested for the presence of Chlamydia spp. antigen using an ELISA antigen kit. Forty (18.4%) of the 217 samples from cats with conjunctivitis were positive. Seven (6%) of 116 samples from cats which were in contact with cats with conjunctivitis but which showed no clinical signs at the time of sample collection were positive. Positive-testing cats were frequently from multi-cat households. Chlamydia spp. is present and associated with conjunctivitis in cats in New Zealand. Infection may occur concurrently with viral diseases. Feline calicivirus was recovered from 27 (21 with conjunctivitis) of 37 cats tested in five catteries. Four cats (with conjunctivitis) were FIV-positive.     

Melatonin reduces apoptotic cells,SOD2 and HSPB1 and improves the in vitro production and quality of bovine blastocysts

Effects of adding different concentrations of melatonin (10^?7, 10^?9 and 10^?11 M) to maturation (Experiment 1; Control, IVM  + 10^?7, IVM  + 10^?9, IVM  + 10^?11) and culture media (Experiment 2; Control, IVC  + 10^?7, IVC  + 10^?9, IVC  + 10^?11) were evaluated on in vitro bovine embryonic development. The optimal concentration of melatonin (10^?9 M) from Experiments 1–2 was tested in both maturation and/or culture media of Experiment 3 (Control, IVM  + 10^?9, IVC  + 10^?9, IVM /IVC  + 10^?9). In Experiment 1, maturated oocytes from Control and IVM  + 10^?9 treatments showed increased glutathione content, mitochondrial membrane potential and percentage of Grade I blastocysts (40.6% and 43%, respectively). In Experiment 2, an increase in the percentage of Grade I blastocysts was detected in IVC  + 10^?7 (43.5%; 56.7%) and IVC  + 10^?9 (47.4%; 57.4%). Moreover, a lower number and percentage of apoptotic cells in blastocysts were observed in the IVC  + 10^?9 group compared to Control (3.8 ± 0.6; 3.6% versus 6.1 ± 0.6; 5.3%). In Experiment 3, the IVC  + 10^?9 treatment increased percentage of Grade I blastocysts with a lower number of apoptotic cells compared to IVM /IVC  + 10^?9 group (52.6%; 3.0 ± 0.5 versus 46.0%; 5.4 ± 1.0). The IVC  + 10^?9 treatment also had a higher mRNA expression of antioxidant gene (SOD 2) compared to the Control, as well as the heat shock protein (HSPB 1) compared to the IVM  + 10^?9. Reactive oxygen species production was greater in the IVM /IVC  + 10^?9 treatment group. In conclusion, the 10^?9 M concentration of melatonin and the in vitro production phase in which it is used directly affected embryonic development and quality.     

Physical aging in polymer glasses

Physical aging refers to structural relaxation of the glassy state toward the metastable equilibrium amorphous state, and it is accompanied by changes in almost all physical properties. These changes, which must be taken into account in the design, manufacture, and use of glassy polymer materials and devices, present a daunting challenge to theorists.     

Hyoscine‐N‐butylbromide premedication on cardiovascular variables of horses sedated with medetomidine

ObjectiveTo evaluate the effects of intravenous (IV) or intramuscular (IM) hyoscine premedication on physiologic variables following IV administration of medetomidine in horses.Study designRandomized, crossover experimental study.AnimalsEight healthy crossbred horses weighing 330 ± 39 kg and aged 7 ± 4 years.MethodsBaseline measurements of heart rate (HR), cardiac index (CI), respiratory rate, systemic vascular resistance (SVR), percentage of patients with second degree atrioventricular (2^oAV) block, mean arterial pressure (MAP), pH, and arterial partial pressures of carbon dioxide (PaCO₂) and oxygen (PaO₂) were obtained 5 minutes before administration of IV hyoscine (0.14 mg kg^?1; group HIV), IM hyoscine (0.3 mg kg^?1; group HIM), or an equal volume of physiologic saline IV (group C). Five minutes later, medetomidine (7.5 μg kg^?1) was administered IV and measurements were recorded at various time points for 130 minutes.ResultsMedetomidine induced bradycardia, 2^oAV blocks and increased SVR immediately after administration, without significant changes in CI or MAP in C. Hyoscine administration induced tachycardia and hypertension, and decreased the percentage of 2^oAV blocks induced by medetomidine. Peak HR and MAP were higher in HIV than HIM at 88 ± 18 beats minute^?1 and 241 ± 37 mmHg versus 65 ± 16 beats minute^?1 and 192 ± 38 mmHg, respectively. CI was increased significantly in HIV (p ≤ 0.05). Respiratory rate decreased significantly in all groups during the recording period. pH, PaCO₂ and PaO₂ were not significantly changed by administration of medetomidine with or without hyoscine.Conclusion and clinical relevanceHyoscine administered IV or IM before medetomidine in horses resulted in tachycardia and hypertension under the conditions of this study. The significance of these changes, and responses to other dose rates, requires further investigation.     

The CAMCORE international provenance/progeny trials of Gmelina arborea: genetic parameters and potential gain

New Forests - This paper reports early results from the provenance/progeny trials in Colombia, Costa Rica, Guatemala, Indonesia, Mexico and Venezuela. These were the first international collections...     

Genetic variation in the ovine uncoupling protein 1 gene: association with carcass traits in New Zealand (NZ) Romney sheep,but no association with growth traits in either NZ Romney or NZ Suffolk sheep

The uncoupling protein 1 (UCP1) plays an important role in the regulation of lipolysis and thermogenesis in adipose tissues. Genetic variation within three regions (the promoter, intron 2 and exon 5) of the ovine UCP1 gene (UCP1) was investigated using polymerase chain reaction‐single‐strand conformational polymorphism (PCR‐SSCP) analyses. These revealed three promoter variants (designated A, B and C) and two intron 2 variants (a and b). The association of this genetic variation with variation in lamb carcass traits and postweaning growth was investigated in New Zealand (NZ) Romney and Suffolk sheep. The presence of B in a lamb's genotype was associated with decreased subcutaneous carcass fat depth (V‐GR) (p = 0.004) and proportion of total lean meat yield of loin meat (p = 0.005), and an increased proportion of total lean meat yield of hind‐leg meat (p = 0.018). In contrast, having two copies of C was associated with increased V‐GR (p < 0.001) and proportion of total lean meat yield of shoulder meat (p = 0.009), and a decreased hind‐leg yield (p = 0.032). No associations were found with postweaning growth. These results suggest that ovine UCP1 is a potential gene marker for carcass traits.