57 research outputs found
Imaging diagnosis - unilateral trigeminal neuritis mimicking peripheral nerve sheath tumor in a horse
Modos de aplicação e doses de fósforo no crescimento do feijoeiro.
Doses crescentes de fĂłsforo (0, 50, 100, 200, 400 e 800 kg ha -1), como KH 2 PO 4, foram aplicadas em um Ultisol para estudar o efeito de nĂveis e modos de aplicação, no desenvolvimento do feijoeiro ( Phaseolus vulgaris L.), cv. Mexicano, em um experimento em casa de vegetação, na cidade de Brisbane, localizada a uma de latitude de 27 25 S, longitude de 152 54 E e altitude de 154 m acima do mar. As temperaturas do ar durante outubro e novembro de 1990 variaram entre a mĂĄxima de 40 Âș C e a mĂnima de 21Âș C. O fĂłsforo foi aplicado em cobertura e incorporado antes do plantio; em faixa apĂłs o plantio; e em sulco no plantio. Os maiores valores de altura de planta e produção de matĂ©ria seca foram obtidos com aplicação das doses mĂ©dias de 535 e 380 kg de fĂłsforo ha-1 , respectivamente. O maior crescimento do feijĂŁo foi observado quando o fĂłsforo foi aplicado a lanço e incorporado ao solo, mas a maior produção de matĂ©ria seca ocorreu quando se aplicou o fĂłsforo em faixa. As concentraçÔes mĂĄximas de nitrogĂȘnio e fĂłsforo no tecido foliar atingiram 20,8 e 2,96g kg-1, respectivamente. A concentração foliar de magnĂ©sio variou entre 2 e 4g kg-1, e a mĂĄxima concentração de cĂĄlcio na folha foi 30 g kg-1 . De acordo com os parĂąmetros da planta usados para avaliar o desenvolvimento do feijoeiro, pode-se considerar que os melhores resultados verificados com a aplicação de fertilizante fosfatado no feijoeiro foram obtidos quando se aplicou o fertilizante em faixa e que a maior altura da planta nĂŁo correspondeu Ă maior produção de matĂ©ria seca
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Ecto- and arbuscular mycorrhizal symbiosis can induce tolerance to toxic pulses of phosphorus in jarrah (Eucalyptus marginata) seedlings
In common with many plants native to low P soils, jarrah (Eucalyptus marginata) develops toxicity symptoms upon exposure to elevated phosphorus (P). Jarrah plants can establish arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) associations, along with a non-colonizing symbiosis described recently. AM colonization is known to influence the pattern of expression of genes required for P uptake of host plants and our aim was to investigate this phenomenon in relation to P sensitivity. Therefore, we examined the effect on hosts of the presence of AM and ECM fungi in combination with toxic pulses of P and assessed possible correlations between the induced tolerance and the shoot P concentration. The P transport dynamics of AM (Rhizophagus irregularis and Scutellospora calospora), ECM (Scleroderma sp.), non-colonizing symbiosis (Austroboletus occidentalis), dual mycorrhizal (R. irregularis and Scleroderma sp.), and non-mycorrhizal (NM) seedlings were monitored following two pulses of P. The ECM and A. occidentalis associations significantly enhanced the shoot P content of jarrah plants growing under P-deficient conditions. In addition, S. calospora, A. occidentalis, and Scleroderma sp. all stimulated plant growth significantly. All inoculated plants had significantly lower phytotoxicity symptoms compared to NM controls 7 days after addition of an elevated P dose (30 mg P kgâ1 soil). Following exposure to toxicity-inducing levels of P, the shoot P concentration was significantly lower in R. irregularis-inoculated and dually inoculated plants compared to NM controls. Although all inoculated plants had reduced toxicity symptoms and there was a positive linear relationship between rank and shoot P concentration, the protective effect was not necessarily explained by the type of fungal association or the extent of mycorrhizal colonization
Injecting bio solids into grass and arable crops. Part I: Design and evaluation of a shallow injector
Shallow injection of liquid bio solids at depths of 50â70 mm into grass and arable crops offers many advantages over existing application methods. However, current shallow injection equipment only places the sludge or slurry into slots leaving it exposed with a high runoff risk. The objective of this study was to determine the benefits and limitations of injecting digested sewage sludge into land growing arable crops using shallow injection techniques. It is documented in two parts. One part describes the agronomic trials undertaken to determine the effect of application technique and timing on combinable crops. This part describes the work undertaken to understand the mechanics of shallow injection and develop an improved injector design. Here, laboratory and field studies were undertaken to compare both existing and new winged shallow injector designs. These showed that a winged injector penetrated better with an equal or lower draught than existing designs. The design also incorporated the sludge into the soil with minimal crop damage at rates of at least of 50 m3 haâ1 when working 50 mm deep
Injecting bio solids into grass and arable crops. Part II: Development of a shallow application technique
Digested sludge contains valuable crop nutrients but these are largely lost because current application techniques limit where and when it can be applied. Soil injection to depths in excess of 150 mm to reduce odour problems can only be used on fallow land or grass because of the damage it can cause. This leads to applications at high rates being applied with increased environmental risk. The aim of this study was to determine the benefits and limitations of injecting digested sewage sludge into land growing arable crops using shallow, less than 100 mm deep, injection techniques. Agronomic trials conducted over 2 years with winter wheat and rape showed that the crops were surprisingly resistant to mechanical damage during the growing season. Crop yields were not effected by injecting sludge into the crop up to March, equivalent to growth stage 30 in winter wheat, using a conventional tractor-based system working. Injection is possible later in the growing season based on systems with the tractor operating along "tramlines" for field traffic control
Management of tropical acid upland soil for sustainable food crop production in southern Thailand
Towards a refinement calculus for concurrent real-time programs
We define a language and a predicative semantics to model concurrent real-time programs. We consider different communication paradigms between the concurrent components of a program: communication via shared variables and asynchronous message passing (for different models of channels). The semantics is the basis for a refinement calculus to derive machine-independent concurrent real-time programs from specifications. We give some examples of refinement laws that deal with concurrency
Effect of Substitution in Stannic ChlorideâMediated Heterocyclization of 4âAllylâ3âhydroxyquinolinâ2(1 H
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