Gravity Research on Plants: Use of Single-Cell Experimental Models

Future space missions and implementation of permanent bases on Moon and Mars will greatly depend on the availability of ambient air and sustainable food supply. Therefore, understanding the effects of altered gravity conditions on plant metabolism and growth is vital for space missions and extra-terrestrial human existence. In this mini-review we summarize how plant cells are thought to perceive changes in magnitude and orientation of the gravity vector. The particular advantages of several single-celled model systems for gravity research are explored and an overview over recent advancements and potential use of these systems is provided

PI Stabilization for Congestion Control of AQM Routers with Tuning Parameter Optimization

In this paper, we consider the problem of stabilizing network using a new proportional- integral (PI) based congestion controller in active queue management (AQM) router; with appropriate model approximation in the first order delay systems, we seek a stability region of the controller by using the Hermite- Biehler theorem, which isapplicable to quasipolynomials. A Genetic Algorithm technique is employed to derive optimal or near optimal PI controller parameters

Using computer tablets to assess preference for videos in children with autism

Using computer tablets, we assessed preference for videos in five children with autism spectrum disorder (ASD). Then, we provided access to most preferred and less preferred videos contingent on sitting on one of two chairs within a concurrent schedule design. All participants spent consistently more time sitting on the chair associated with the video selected the most often during the preference assessment, indicating that practitioners may use the tablet-based assessment procedure to identify potential video reinforcers for children with ASD in applied settings

Phytochemical screening and antioxidant activity of four Moroccan aromatic plant methanolic extracts and essential oils

This work aimed to evaluate and to compare the antioxidant potential between essential oils (EOs) and methanolic extracts (MEs) of Anthemis tenuisecta, Cladanthus arabicus Cass., Ismelia carinata Schousb., and Thymus broussonetii Boiss subsp. broussonetii collected from Morocco. The EOs used in this study were isolated by hydrodistillation using a Clevenger-type apparatus. The MEs were obtained by methanol maceration. The main compounds of EOs were identified using gas chromatography-mass spectrometry. The MEs of the four plant species were tested for total phenolics and total flavonoids. The in vitro antioxidant activity of EOs and MEs was carried out using diphenyl-1-picrylhydrazyl (DPPH) assay. The antioxidant activity of MEs showed high correlations with phenolic compounds. For both fractions, the best IC50 values were given by T. broussonetii. The MEs revealed significantly (p ≤ 0.05) better antioxidant activity than EOs. The results suggest that A. tenuisecta, C. arabicus, I. carinata, and T. broussonetii may be potential sources of natural antioxidants

Modification de polysaccharides naturels pour l'obtention de nouveaux excipients pharmaceutiques (Liants, délitants et agents de libération contrôlée)

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Prevalence of stereotypy in individuals with developmental disabilities: a systematic review

Although many researchers have examined the prevalence of stereotypy in individuals with developmental disabilities, the results of previous studies have not been aggregated and analyzed methodically. Thus, we conducted a systematic review of studies reporting the prevalence of stereotypy in individuals with developmental disabilities. Our results indicated that the average prevalence of stereotypy across studies was 61 % and that individuals with autism spectrum disorders had the highest reported prevalence (i.e., 88 %) across specific diagnoses. Children and adults generally had similar overall prevalence measures, but the specific forms varied with age and diagnosis. Studies using the Repetitive Behavior Scale-Revised and the Autism Diagnostic Schedule-Revised generally reported higher estimates of prevalence of specific forms of stereotypy when compared to the Behavior Problem Inventory. However, the latter seemed more sensitive than the Aberrant Behavior Checklist for overall prevalence. Studies with a low risk of bias found a lower prevalence of stereotypy than those with a high risk of bias. Our systematic review underlines the importance of continuing research efforts to improve the assessment and treatment of stereotypy in individuals with developmental disabilities

Comparison of tablet-delivered and instructor-delivered teaching on receptive identification in children with autism spectrum disorders

The purpose of our study was to compare the effectiveness of tablet- and instructor-delivered teaching (i.e., prompting and reinforcement) on the receptive identification of one-word concepts in children with autism spectrum disorders (ASDs). To this end, we embedded a multielement design within a multiple probe design to compare the effectiveness of the two instructional modalities in seven participants. Two of the seven participants showed generalization on all concepts in fewer instructional trials following instructor-delivered teaching, whereas the remaining five participants had mixed results depending on the concept. In total, the participants showed more rapid generalization with the instructor for 14 of the 19 concepts taught. Our results suggest that tablets should not systematically replace instructor-delivered prompting and reinforcement, but that they may be used to provide supplementary teaching to children with ASD

The Occurrence of Major Viruses Infecting Zucchini Squash (Cucurbita pepo L.) in Morocco

Zucchini squash, Cucurbita pepo L., is one of the most economically important vegetable crops in Morocco. Virus diseases are a major factor in limiting production of zucchini squash in the country. During the growing seasons 2015, 2016 and 2017, the main areas of field-grown cucurbit production in Morocco (Loukkos, Gharb, Bouznika, Doukkala and Souss) were surveyed for the occurrence and distribution of viruses of zucchini squash. A total of 38 commercial fields were visited and inspected for symptoms of virus diseases and 415 leaf samples were collected from plants showing virus-like symptoms for laboratory analyses. ELISA technique was used to detect the following viruses: Zucchini yellow mosaic virus (ZYMV), Squash mosaic virus (SqMV), Cucumber mosaic virus (CMV), Papaya ringspot virus-watermelon strain (PRSV-W) and Cucurbit aphid-borne yellows virus (CABYV). The obtained results showed that virus diseases were widely distributed in the country with an infection rate of 77.6%, especially in the region of Loukkos where 85% of the tested plants were infected by at least one virus. To the best of our knowledge, this isthe first study on the occurrence and geographical distribution of viruses infecting zucchini squash in Morocco. This study provides valuable information, which could be beneficial and of great interest for the researchers, growers and the plant protection services for planning future strategies to control virus diseases of zucchini squash in Morocco