124 research outputs found

    Environmental Biotechnology Screening Cu and Cd tolerance in Salix species from North Morocco

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    Hydroponic culture has been used to compare copper and cadmium tolerance in five Salix species from North Morocco using different approaches. Measurements of growth parameters have been combined with those of some photosynthetic parameters. Tolerance index based either on root or shoot growth allowed to define Salix pedicelata and Salix purpurea as Cu and Cd-tolerant species, respectively. From the methodological point of view, the use of tolerance index based on aerial part growth, appeared mostadequate for the screening of metal tolerance in woody plants. On the other hand, no significant effect on chlorophyll content was observed under treatment with either Cu or Cd, in any of the Salix species analyzed. In vitro experiments with thylakoid membranes showed that the effects on the electron transport chain differ for each metal and species used. Furthermore, it seems that metal tolerance at the chloroplast level is distinct to that of the whole plant

    Assessing students\u27 foundation skills prior to the STEM majors

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    To increase the employability of STEM graduates and their readiness as scientific and technical knowledge workers for the 21st Century knowledge economies, higher education must emphasise what are known as foundation skills, such as critical thinking, quantitative reasoning, communication and teamwork, to name a few. Quality assurance organisations, such as ABET (the international accrediting body for technical fields) and national higher education accrediting bodies require programmes to show evidence of student attainment of foundation skills. Such skills, however, are recognised as difficult to both teach and assess. In earlier articles, the authors have described and presented preliminary results and findings from an assessment framework - The General Education Foundation Skills Assessment (GEFSA) - used to measure and assess the attainment of foundation skills for non-native English speaking students in a general education programme (i.e. pre-major students) at Zayed University in the United Arab Emirates. This article focuses on recent GEFSA testing with students in their first and last semesters of the general education programme

    Is a multiple excitation of a single atom equivalent to a single excitation of an ensemble of atoms?

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    Recent technological advances have enabled to isolate, control and measure the properties of a single atom, leading to the possibility to perform statistics on the behavior of single quantum systems. These experiments have enabled to check a question which was out of reach previously: Is the statistics of a repeatedly excitation of an atom N times equivalent to a single excitation of an ensemble of N atoms? We present a new method to analyze quantum measurements which leads to the postulation that the answer is most probably no. We discuss the merits of the analysis and its conclusion.Comment: 3 pages, 3 figure

    Measuring attainment of foundation skills in general education at a public university in the United Arab Emirates

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    © 2016 WIETE. To increase the employability of graduates, tertiary education must emphasise what are known as foundational skills, such as critical thinking, teamwork and information literacy, to name a few. These skills, however, are recognised as difficult to both teach and assess. In this article, the authors describe a novel performance assessment - the General Education Foundational Skills Assessment (GEFSA) - that can be used to teach and measure attainment of foundational skills for non-native English speaking students in a General Education programme, and the results of a pilot study conducted at Zayed University in the United Arab Emirates. The GEFSA is comprised of a scenario of an unresolved contemporary issue, prompts to engage students in an on-line discussion, and a task-specific analytic rubric to assess the extent to which students attain the targeted skills. This article focuses on the GEFSA Rubric development and the supporting instruments. The pilot study results indicated that the method could be used to both teach and measure the foundation skills, as well as to be used for programme assessment reporting purposes

    From Traditional Farming in Morocco to Early Urban Agroecology in Northern Mesopotamia: Combining Present-day Arable Weed Surveys and Crop Isotope Analysis to Reconstruct Past Agrosystems in (Semi-)arid Regions

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    Published by Informa UK Limited, trading as Taylor & Francis GroupWe integrate functional weed ecology with crop stable carbon and nitrogen isotope analysis to assess their combined potential for inferring arable land management practices in (semi-)arid regions from archaeobotanical assemblages. Weed and GIS survey of 60 cereal and pulse fields in Morocco are combined with crop sampling for stable isotope analysis to frame assessment of agricultural labour intensity in terms of manuring, irrigation, tillage and hand-weeding. Under low management intensity weed variation primarily reflects geographical differences, whereas under high management intensity fields in disparate regions have similar weed flora. Manured and irrigated oasis barley fields are clearly discriminated from less intensively manured rain-fed barley terraces in southern Morocco; when fields in northern and southern Morocco are considered together, climatic differences are superimposed on the agronomic intensity gradient. Barley ÎŽ13C and ÎŽ15N values clearly distinguish among the Moroccan regimes. An integrated approach combines crop isotope values with weed ecological discrimination of low- and high-intensity regimes across multiple studies (in southern Morocco and southern Europe). Analysis of archaeobotanical samples from EBA Tell Brak, Syria suggests that this early city was sustained through extensive (low-intensity, large-scale) cereal farming

    Weak localization in disordered systems at the ballistic limit

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    The weak localization (WL) contribution to the two-level correlation function is calculated for two-dimensional disordered conductors. Our analysis extends to the nondiffusive (ballistic) regime, where the elastic mean path is of order of the size of the system. In this regime the structure factor (the Fourier transform of the two-point correlator) exhibits a singular behavior consisting of dips superimposed on a smooth positive background. The strongest dips appear at periods of the periodic orbits of the underlying clean system. Somewhat weaker singularities appear at times which are sums of periods of two such orbits. The results elucidate various aspects of the weak localization physics of ballistic chaotic systems.Comment: 13 pages, 13 figure

    Aridity gradients shape intraspecific variability of morphological traits in native Ceratonia siliqua L. of Morocco

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    The carob tree (Ceratonia siliqua L.) is a significant fruit tree in the Mediterranean region with cultural, biological, and ecological importance. Despite its importance, intraspecific trait variability (ITV) in carob trees has been largely overlooked in previous studies. Understanding ITV and its relationship with environmental conditions is crucial for conservation and breeding programs. In this study, we investigated the variability of carob pod and seed-related traits across different ecological scales in 25 studied populations in Morocco. Significant differences in morphological traits were observed between carob populations at various ecological levels, and pod-related traits exhibited greater variability than seed traits. Correlation analysis revealed strong associations between carob morphological traits and environmental conditions, with altitude and aridity index playing an influential role. The aridity gradient was strongly related to changes in pod size, seed number, and size, as well as seed yield. Our findings highlight an important ITV reaching 45% at the intra-population level, 36.5% at the inter-geographic level, and 30% at the inter-population level. Overall, this study contributes valuable insights into the ecology and adaptation of carob trees, emphasizing the importance of considering intraspecific variability when studying this remarkable species. This knowledge is critical for addressing the challenges posed by climate change and human activities on the long-term survival and ecological functioning of carob populations

    Phase II TPDCV protocol for pediatric low-grade hypothalamic/chiasmatic gliomas: 15-year update

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    To report long-term results for children with low-grade hypothalamic/chiasmatic gliomas treated on a phase II chemotherapy protocol. Between 1984 and 1992, 33 children with hypothalamic/chiasmatic LGGs received TPDCV chemotherapy on a phase II prospective trial. Median age was 3.0 years (range 0.3–16.2). Twelve patients (36%) underwent STRs, 14 (42%) biopsy only, and seven (21%) no surgery. Twenty patients (61%) had pathologic JPAs, nine (27%) grade II gliomas, and four (12%) no surgical sampling. Median f/u for surviving patients was 15.2 years (range 5.3–20.7); 20 of the 23 surviving patients had 14 or more years of follow-up. Fifteen-year PFS and OS were 23.4 and 71.2%, respectively. Twenty-five patients progressed, of whom 13 are NED, two are AWD, and 10 have died. All children who died were diagnosed and first treated at age three or younger. Age at diagnosis was significantly associated with relapse and survival (P = 0.004 for PFS and P = 0.037 for OS). No PFS or OS benefit was seen with STR versus biopsy/no sampling (P = 0.58 for PFS, P = 0.59 for OS). For patients with JPAs and WHO grade II tumors, the 15-year PFS was 18.8 and 22.2% (P = 0.95) and 15-year OS was 73.7 and 55.6% (P = 0.17), respectively. Upfront TPDCV for children with hypothalamic/chiasmatic LGGs resulted in 15-year OS of 71.2% and 15-year PFS of 23.4%. No survival benefit is demonstrated for greater extent of resection. Age is a significant prognostic factor for progression and survival
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