248 research outputs found

    Survival and development of Bactrocera oleae Gmelin (Diptera:Tephritidae) immature stages at four temperatures in the laboratory

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    Bactrocera oleae Gmelin (Diptera:Tephritidae) is the most important and widespread pest in the olive growing countries in the Mediterranean basin. The development and survival of olive fruit fly, B. oleaefrom egg to adult stage was studied in the laboratory at 16, 22, 27 and 35°C. The objective of the study was to get information on the influence of temperature on immature stages as a prerequisite to optimizerearing procedures and to understand geographical pattern of fruit fly occurrence. Embryonic development was fastest at 35°C but there was no pupal development and, of course, no adults at 35°C. The slowest development of immature stages was at 16°C. The highest percentage of adults obtained from an initial set of 100 eggs was 74% at 27°C. The lower development thresholds for the egg, larval and pupal stages were 9.19, 13.94 and 12.36°C, respectively. The optimum temperature for development and survival of immature stages was 27°C

    Vegetation indices as indicators of damage by the sunn pest (Hemiptera: Scutelleridae) to field grown wheat

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    The sunn pest, Eurygaster integriceps Put. (Hemiptera: Scutelleridae), also known as sting or cereal pest, is one of the most economically important pests of wheat in the world. In this study, a collapsiblenylon cloth cage experiments were conducted to determine the feasibility of using remote sensing techniques to detect stress in wheat caused by the density of sunn pests. The results show we candetect the amount of stress in wheat caused by different life stages of sunn pest with a hand-held radiometer. Normalized difference vegetation index (NDVI) based indices; NDVIsg, NDVId, NDVIr, andstructure insensitive pigment index (SIPI) were chosen out of 19 indices initially tested. The NDVI based vegetation indices derived from hyperspectral data, recorded by a hand held spectroradiometer, were used to determine the predicted indices using the initial number of Sunn Pest (NOSP). Overall, r2 values of all predicted indices calculated for 3rd instars were lower than those of 4th and adult stage. When r2was considered separately, predicted NDVIr index value (87.4) was the highest and predicted SIPI index value is lowest (80.7) in 3rd instars. The highest r2 value was obtained in adult stage of sunn pest isNDVIsg (96.9) compare with NDVId (95.5), NDVIr (92.4) and SIPI (94.2). It was also concluded that remote sensing could detect not only the different stages pest damage on wheat, but also the number of sunnpest stages density affect in controlled experiments

    Novel critical point drying (CPD) based preparation and transmission electron microscopy (TEM) imaging of protein specific molecularly imprinted polymers (HydroMIPs)

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    We report the transmission electron microscopy (TEM) imaging of a hydrogel-based molecularly imprinted polymer (HydroMIP) specific to the template molecule bovine haemoglobin (BHb). A novel critical point drying based sample preparation technique was employed to prepare the molecularly imprinted polymer (MIP) samples in a manner that would facilitate the use of TEM to image the imprinted cavities, and provide an appropriate degree of both magnification and resolution to image polymer architecture in the <10 nm range. For the first time, polymer structure has been detailed that clearly displays molecularly imprinted cavities, ranging from 5-50 nm in size, that correlate (in terms of size) with the protein molecule employed as the imprinting template. The modified critical point drying sample preparation technique used may potentially play a key role in the imaging of all molecularly imprinted polymers, particularly those prepared in the aqueous phase

    The Pheromone of the Cave Cricket, Hadenoecus cumberlandicus, Causes Cricket Aggregation but Does Not Attract the Co-Distributed Predatory Spider, Meta ovalis

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    Food input by the cave cricket, Hadenoecus cumberlandicus Hubble & Norton (Orthoptera: Rhaphidophoridae), is vital to the cave community, making this cricket a true keystone species. Bioassays conducted on cave walls and in the laboratory show that clustering in H. cumberlandicus is guided by a pheromone, presumably excreta. This aggregation pheromone was demonstrated by using filter paper discs that had previous adult H. cumberlandicus exposure, resulting in > 70% response by either nymphs or adults, prompting attraction (thus, active component is a volatile), followed by reduced mobility (arrestment) on treated surfaces. Adults were similarly responsive to pheromone from nymphs, agreeing with mixed stage composition of clusters in the cave. Effects of [0.001M – 0.1M] uric acid (insect excreta's principle component) on H. cumberlandicus behavior were inconsistent. This pheromone is not a host cue (kairomone) and is not used as a repellent (allomone) as noted through lack of responses to natural H. cumberlandicus pheromone and uric acid concentrations by a co-occurring predatory cave orb weaver spider, Meta ovalis Gertsch (Araneae: Tetragnathidae). This pheromone is not serving as a sex pheromone because nymphs were affected by it and because this population of H. cumberlandicus is parthenogenic. The conclusion of this study is that the biological value of the aggregation pheromone is to concentrate H. cumberlandicus in sheltered sites in the cave conducive for minimizing water stress. Rather than signaling H. cumberlandicus presence and quality, the reduced mobility expressed as a result of contacting this pheromone conceivably may act as a defense tactic (antipredator behavior) against M. ovalis, which shares this favored habitat site

    Interventions to prevent youth violence in Latin America: a systematic review

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    Objectives: This review aims to summarise evidence on the effectiveness of interventions to prevent youth violence in Latin America. Methods: A systematic search on 13 academic databases was conducted to locate studies evaluating a primary or secondary prevention intervention in Latin America. Studies could use any type of quantitative design to assess outcomes related to youth violence. A search of websites, references and citation searching was also carried out. The quality of each study was assessed. Results: Nine studies were identified. Most documented positive effects of the interventions on the perception of youth violence present in the community/school. Evidence was found of a reduction in homicides and juvenile crimes in three studies, two of which evaluated a community-based intervention. There were mixed results for the self-report of participation on violent acts. The majority of the studies lacked of a rigorous design. Conclusions: Most of the interventions had some promising results, including the reduction of homicides within communities. Community-based programmes were the most consistent regarding an effectiveness to prevent violence. However, the evidence for Latin America is still scarce and relies on non-rigorously designed studies

    Depth of reading vocabulary in hearing and hearing-impaired children

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    The main point of our study was to examine the vocabulary knowledge of pupils in grades 3–6, and in particular the relative reading vocabulary disadvantage of hearing-impaired pupils. The achievements of 394 pupils with normal hearing and 106 pupils with a hearing impairment were examined on two vocabulary assessment tasks: a lexical decision task and a use decision task. The target words in both tasks represent the vocabulary children should have at the end of primary school. The results showed that most hearing pupils reached this norm, whereas most hearing-impaired pupils did not. In addition, results showed that hearing-impaired pupils not only knew fewer words, but that they also knew them less well. This lack of deeper knowledge remained even when matching hearing and hearing-impaired children on minimal word knowledge. Additionally, comparison of the two tasks demonstrated the efficacy of the lexical decision task as a measure of lexical semantic knowledge

    Early uptake of HIV counseling and testing among pregnant women at different levels of health facilities - experiences from a community-based study in Northern Vietnam

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    <p>Abstract</p> <p>Background</p> <p>HIV counselling and testing for pregnant women is a key factor for successful prevention of mother to child transmission of HIV. Women's access to testing can be improved by scaling up the distribution of this service at all levels of health facilities. However, this strategy will only be effective if pregnant women are tested early and provided enough counselling.</p> <p>Objective</p> <p>To assess early uptake of HIV testing and the provision of HIV counselling among pregnant women who attend antenatal care at primary and higher level health facilities.</p> <p>Methods</p> <p>A community based study was conducted among 1108 nursing mothers. Data was collected during interviews using a structured questionnaire focused on socio-economic background, reproductive history, experience with antenatal HIV counselling and testing as well as types of health facility providing the services.</p> <p>Results</p> <p>In all 91.0% of the women interviewed had attended antenatal care and 90.3% had been tested for HIV during their most recent pregnancy. Women who had their first antenatal checkup at primary health facilities were significantly more likely to be tested before 34 weeks of gestation (OR = 43.2, CI: 18.9-98.1). The reported HIV counselling provision was also higher at primary health facilities, where women in comparison with women attending higher level health facilities were nearly three or and four times more likely to receive pre-test (OR = 2.7; CI:2.1-3.5) and post-test counseling (OR = 4.0; CI: 2.3-6.8).</p> <p>Conclusions</p> <p>The results suggest that antenatal HIV counseling and testing can be scaled up to primary heath facilities and that such scaling up may enhance early uptake of testing and provision of counseling.</p
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