The whitefly, Bemisia tabaci, an insect of the order Hemiptera which attacks more than 600 species of plants, is one of the most important agricultural pests around the world. The insecticidal Cry proteins from Bacillus thuringiensis (Bt) are useful biological pesticides, and some are toxic to Hemipteran insects. In this study, Colombian native isolates of Bt were functionally characterized at molecular and biological levels. The strains contained between one and five different crystal shapes: round, triangular, amorphous, bipyramidal and squared. The strains presented between three to seven bands of proteins in their electrophoretic pattern that were organized into six groups according to their possible biological activity on insect pests. Cry1Aa, cry1Ab, cry1Ac, cry1B and cry1C genes were identified for PCR in the different Bt isolates. Bioassays were performed on tomato leaves whose surface was spread with 3 μg · ml−1 crude extract of Bt toxins. Second instar larvae of whitefly, which were placed on top of leaves and exposed to the toxins for 7 days, exhibited mortalities from 18 to 69%. The lethal concentration 50 (LC50) of ZBUJTL39, Bt kurstaki HD1 and ZCUJTL9 strains were 1.83, 1.85 and 2.16 μg · ml−1, respectively (p < 0.05). These results show that the native Bt strain ZBUJTL39, which contained the genes cry1Aa, cry1Ab, cryCa and cryBa could eventually be used for the development of an integrated management program together with other tools for the control of B. tabaci.

Non−uniformity noise, it was, it is, and it will probably be one of the most non−desired attached companion of the infrared focal plane array (IRFPA) data. We present a higher order filter where the key advantage is based in its capacity to estimates the detection parameters and thus to compensate it for fixed pattern noise, as an enhancement of Constant Statistics (CS) theory. This paper shows a technique to improve the convergence in accelerated way for CS (AACS: Acceleration Algorithm for Constant Statistics). The effectiveness of this method is demonstrated by using simulated infrared video sequences and several real infrared video sequences obtained using two infrared cameras

The article presents an assessment of the effects of anthropogenic activities on the quality of water in four streams flowing through a camp based on a combined assessment of environmental impacts and the water quality index. The quantitative and qualitative assessment of environmental impact was made after identifying the anthropogenic activities carried out in the camp. The water quality index ( WQI) was calculated after monitoring seventeen physicochemical and microbiological variables and the Montoya index was applied. The samples were collected during 48 sampling campaigns, organised over the period of six months in eight stations. Two stations were located in each stream, one before and one after it passed through the camp. The results indicated that streams 1, 3, and 4 show a slight deterioration in water quality, affected by anthropogenic activities carried out in the said camp; meanwhile, stream 2 shows an increasing deterioration in water quality. The water quality of the streams before passing through the camp was determined to be between “uncontaminated” and “acceptable”, while after passing through the camp it was classified between “acceptable” and “slightly contaminated”. The results indicated a non-significant difference between the downstream and upstream WQI values for streams 1, 3, and 4; while stream 2 did show a significant difference in the WQI between upstream and downstream; indicating that anthropogenic activities alter the quality of the water.