A review of autonomous navigation systems in agricultural environments

Mobile robots operating in agricultural environments have been a significant subject for researchers. The rapid advancement in communication, sensors and computing technologies has provided important progress in the field of agricultural autonomous robot guidance systems. Automated agricultural robots save labour costs, prevent people from performing risky operations, and provide the farmer with up-to-date and precise information to assist management decisions. The research on mobile robot navigation systems in agricultural environments consists of designing suitable systems for sensing, mapping, localisation, path planning, and obstacle avoidance. The navigation algorithm must use sensory information to determine a suitable trajectory, make a decision, and move correctly within its environment without collision. In this paper, an overview of navigation systems for autonomous agricultural vehicles is presented and discussed. The key elements are navigational sensors, computational techniques, and navigation control strategies. The selection, coordination, and combination of the optimal sensors to provide the basic information for mobile robot navigation are critical processes. Powerful algorithms are used for feature extraction, data processing and fusion. For autonomous navigation, steering controllers provide an appropriate steering action to automatically drive vehicles. Navigation of mobile robots in outdoor environments such as agricultural applications is still an open problem. The design of efficient and robust sensing and control systems for agricultural mobile robots is required to overcome the difficulties due to the weather conditions, dynamic environments, unexpected obstacles, terrain nature variations and vegetation

Molecular characterization of integrons and Genotyping of Salmonella enterica isolated from diarrheal animals and humans

Resistance to antibacterial drugs is a major health problem because of its impact . It is important to study the prevalence of antibiotic resistance genes in order to understand.Twenty five Salmonella enterica isolated from human and animal diarrhea. Traditional culture methods, biochemical methods, and molecular methods were used to characterize the samples during December to September 2020  to 2021. Disk diffusion method was used to determine antimicrobial susceptibility patterns of isolates identified as MDR by the Clinical and Laboratory Standards Institute (CLSI). The PCR amplification was used to show presence of class 1, 2 and 3 integrons. Class 1 integrons and class3  were detected in 100% of the multidrug-resistant Salmonella isolates,whlie class2 detected among 40%. RAPD-PCR fingerprinting regarded successfully as a reliable, reproducible, accurate and sensitive discriminatory method to Salmonella enterica. The results of RAPD-PCR amplification of Salmonella enterica  isolates revealed that 24 isolates (96.%) also showed about one to six amplification bands per isolate, except one isolates  were untypeble. The most frequent band was a 1400bp band (72%), while the lowest frequent band was 400bp (8%) among an individual isolates

Ilusórias sementes Seeds of illusion

Os autores reconhecem que a discussão em torno dos organismos geneticamente modificados (OGMs), apresentada tanto na literatura científica como na mídia brasileira é, em geral, altamente tendenciosa a favor da liberação desses produtos. Raros são os artigos que questionam profundamente os efeitos, no Brasil, de uma possível introdução desses organismos geneticamente modificados, seja do ponto de vista técnico, social, econômico, ou político. O objetivo geral do artigo foi, com base na literatura existente sobre o assunto, tentar preencher algumas dessas lacunas, consideradas extremamente importantes para o processo de avaliação. Os autores tentaram também apontar algumas das formas de viés que a mídia apresenta em relação aos OGMs. O estudo conclui que, embora os argumentos apresentados a favor dos OGMs possam ser facilmente rechaçados de um ponto de vista técnico, a transformação dos mesmos em uma realidade mercadológica depende, acima de tudo, de uma ordem social comandada pelo capital, hoje representado principalmente pelas grandes corporações e seus aliados, a começar pelo Estado. Esta é a causa principal do viés encontrado na mídia.<br>The authors recognize that the discussion about genetically modified organisms (GMOs), presented by Brazilian scientific literature as well as the media is, in general, highly biased towards approval of these products. Very few articles go deeper into questioning the effects of a possible introduction of these genetically modified organisms in Brazil, be it from a technical, social, economic, or political viewpoint. The general objective of the article was to try, based on the existing literature on the subject, to fulfill some of these omissions, considered extremely important to the evaluation process. The authors also tried to point out some of the ways of bias used by the media with respect to GMOs. The main conclusion of the study was that, although the presented arguments in favor of GMOs can be easily rejected from a technical viewpoint, the transformation of GMOs into a commercial reality depends, above all, upon a social order commanded by capital, presently represented mainly by large corporations and their allies, beginning with the State. This is the most important cause for the bias found in the media