Sampling procedures and damage thresholds for root-knot nematode (Meloidogyne javanica) on pineapple

The relationship between the population density of root-knot nematode (Meloidogyne javanica) and pineapple yield was studied by establishing different nematode densities in field plots at 3 sites. Differences in nematode populations between treatments were apparent 9–22 months after planting, but yields in the plant crop were similar, regardless of nematode density. In the ratoon crop, yields in treatments with less than 10 nematodes/200 mL soil at 9–22 months were reduced by about 10%. Yield reductions of more than 25% occurred when population densities were greater than 50 nematodes/200 mL soil. These results demonstrate that economically significant crop losses from root-knot nematodes can occur in pineapple when the population density at 12 months is greater than 1–5 nematodes/200 mL soil. The sampling procedures required to obtain reliable estimates of M. javanica in pineapple fields were determined by studying nematode distribution in 2 fields in south-east Queensland. Nematodes were extracted from more than 100 individual soil cores on a 5 by 5 m grid and populations were found to have a clumped rather than random distribution. A composite sample of 41 cores in 1 field and 72 cores in the other gave a relatively precise estimate of the population of root-knot nematodes (i.e. standard error : mean ratio of 0.3). These data suggest that a 50-core sampling unit is appropriate when nematode population density is being estimated for decision-making purposes

A BLENDED-LEARNING APPROACH IN UNDERGRADUATE SOIL SCIENCE INTERRUPTED BY COVID-19

We investigated the impact of the interruption caused by COVID-19 restrictions on student engagement and achievement in a third year soil science course taught across two campuses simultaneously by the same teaching staff. Initially, the first three weeks of semester were taught in a blended-learning approach – each week there were three 20 minute lectures posted online with a three hour face-to-face laboratory practical, and each fortnight a face-to-face tutorial was scheduled. Due to the COVID-19 pandemic, week four became a pause in teaching at our institution, thereafter all teaching and learning was conducted exclusively online for the remainder of semester. Face-to-face tutorials were replaced by Zoom sessions and the laboratory practicals were posted on Blackboard as videos. We assessed student engagement by monitoring attendance at both face-to-face and online tutorials and analysed the frequency and timing of access to all learning materials available via Blackboard throughout semester. We examined if student overall course performance was a function of online engagement. We observed differences in attendance and online behaviour as a function of course delivery mode. We examined the impact of a major interruption to teaching and learning activities due to COVID-19 and the impact of this interruption on student engagement

Toxic effects of Pb2+ on growth of cowpea (Vigna unguiculata)

A concentration as low as 1 mu M lead (Pb) is highly toxic to plants, but previous studies have typically related plant growth to the total amount of Pb added to a solution. In the present experiment, the relative fresh mass of cowpea (Vigna unguiculata) was reduced by 10% at a Pb2+ activity of 0.2 mu M for the shoots and at a Pb2+ activity of 0.06 mu M for the roots. The primary site of Pb2+ toxicity was the root, causing severe reductions in root growth, loss of apical dominance (shown by an increase in branching per unit root length), the formation of localized swellings behind the root tips (due to the initiation of lateral roots), and the bending of some root tips. In the root, Pb was found to accumulate primarily within the cell walls and intercellular spaces. (C) 2007 Elsevier Ltd. All rights reserved

Guardas Municipais: entre a tentação da tradição e o desafio da inovação

O Brasil vive pela terceira vez, nos últimos 200 anos, o debate sobre o papel das Guardas Civis. Este artigo busca colaborar com este debate fazendo uma retrospectiva histórica sobre o tema e busca demonstrar como a Lei 13022/2014 abriu um debate muito mais amplo e relevante sobre a concepção de Segurança Pública existente no país. O presente artigo discute o conceito de prevenção apresentado na Ação Direta de Inconstitucionalidade (ADIN 5651) como argumento principal contra o Estatuto das Guardas Municipais, o qual utiliza doutrina consolidada durante a Ditadura Militar, que resume prevenção a policiamento ostensivo, o que se encontra superado em nível mundial por uma concepção muito mais abrangente de ações multidisciplinares de prevenção e que já se encontra recepcionada na Legislação nacional. Por fim, o artigo apresenta algumas das políticas preventivas que tem sido implementadas pela Secretaria de Segurança da cidade de Canoas (RS), com protagonismo da Guarda Municipal, uma experiência concreta dessa nova concepção de Segurança Pública proativa, preventiva, integrada, com planejamento de longo prazo e baseada em evidências, na qual as Guardas atuam de forma integrada com as polícias estaduais e não disputando os mesmos papéis ou copiando os mesmos modelos e concepções

A sampling strategy to assess banana crops for damage by Radopholus similis and Pratylenchus goodeyi

The economic threshold of burrowing (Radopholus similis) and lesion nematode (Pratylenchus goodeyi) on banana may be used to determine whether it is economic to apply nematicide. However, to use such a threshold, a sampling strategy is essential to determine the severity of root damage caused by the nematode. Ten banana crops in south-eastern Queensland and northern New South Wales and 10 in northern Queensland were sampled several times over several years to determine the disease index (percentage cortical root damage caused by R. similis and P. goodeyi) and nematode populations in roots. The negative binomial distribution and Taylor’s power law analysis were used to determine the relationship between the mean and variance of the disease index and nematode populations. Taylor’s power law gave the better fit, and was therefore used to determine fixed-precision stop lines for sequential sampling for precision at 20–30% for disease index and 20–40% for nematode populations. Twenty samples per crop were sufficient to achieve 25% precision when assessing nematode infestations using disease index but only 40% precision when using nematode populations

DEMOCRACY THAT DELIVERS: Uma análise da atuação do Center for International Private Enterprise (CIPE) na América Latina (2008-2012)

TCC (graduação) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas, Curso de Ciências Sociais.O Center for International Private Enterprise - CIPE é uma organização privada americana ligada à Câmara de Comércio dos Estados Unidos (USCC) que opera com recursos do governo americano. Foi criado com o intuito de operar no exterior e tem como missão a promoção da democracia e do Livre-Mercado. Sua atuação se dá através de projetos, em parcerias com organizações locais, ligadas ao empresariado. Na presente pesquisa, estudamos suas atividades na América Latina, em torno da Governança Democrática – quais dos seus valores são professados pelo Centro e suas implicações estratégicas e políticas. Esse estudo foi feito através de uma pesquisa documental e bibliográfica aprofundada, onde foram identificados os projetos e parcerias mantidos pelo CIPE no período, além dos recursos financeiros e os objetivos relativos a cada projeto. Recorreu-se a análise de documentos chave do CIPE, no período estudado, para identificar os valores de Governança Democrática presentes. Depois, foi empreendida uma análise comparativa, buscando compreender a interação estratégica desses valores nos projetos mantidos pelo Centro na América latina

Evaluation of extractants for estimation of the phytoavailable trace metals in soils

Despite its environmental (and financial) importance, there is no agreement in the literature as to which extractant most accurately estimates the phytoavailability of trace metals in soils. A large dataset was taken from the literature, and the effectiveness of various extractants to predict the phytoavailability of Cd, Zn, Ni, Cu, and Pb examined across a range of soil types and contamination levels. The data suggest that generally, the total soil trace metal content, and trace metal concentrations determined by complexing agents (such as the widely used DTPA and EDTA extractants) or acid extractants (such as 0.1 M HCl and the Mehlich 1 extractant) are only poorly correlated to plant phytoavailability. Whilst there is no consensus, it would appear that neutral salt extractants (such as 0.01 M CaCl2 and 0.1 M NaNO3) provide the most useful indication of metal phytoavailability across a range of metals of interest, although further research is required