46 research outputs found

    Bioprospecting autochthonous marine microalgae strain from the Arabian Gulf Seawater, Kuwait for biofuel feedstocks

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    Bioprospecting programs are the key to increasing the current portfolio of indigenous microalgal strains accessible for different applications in microalgal biotechnology. In this work, nine fast-growing microalgal strains isolated from Kuwait's Arabian/Persian Gulf coastal waters were evaluated for their potential as biofuel feedstocks. 18S rRNA gene sequencing showed that the strains belong to five different genera: Chlorella, Nannochloris, Scenedesmus, Tetraselmis, and Nannochloropsis. In terms of the total lipid content, in comparison to the other strains, Tetraselmis sp. KUBS13G and Tetraselmis sp. KUBS16G displayed higher lipid contents of 29.56% dry weight (DW) and 26.13% DW, respectively, dominated by palmitic and oleic acids. Fuel properties calculated from the fatty acid methyl esters (FAMES) by empirical equations were compared with EN14214 (European) and ASTM D6751--02 (American) biodiesel standards. Multicriteria decision analysis (MCDA) methods, such as the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GALA), were used to select suitable microalgae for biofuel feedstock based on their biodiesel fuel properties. Overall, the results suggested that the indigenous microalgal strain Tetraselmis, particularly Tetraselmis sp. KUBS37G, and Scenedesmus sp. KUB Sl7R are the most suitable strains for biofuel feedstock owing to their improved fuel properties, such as density (rho) (0.88 g cm-3), low kinematic viscosity (3.1 mm2 s-1), high cetane number (54 and 56, respectively), high oxidation stability (14.6 hr and 14.8 hr), and cold filter plugging point (1.0 degrees C and -6.1 degrees C).info:eu-repo/semantics/publishedVersio

    Biological activities and chemical composition of methanolic extracts of selected Autochthonous microalgae strains from the Red Sea

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    Four lipid-rich microalgal species from the Red Sea belonging to three different genera (Nannochloris, Picochlorum and Desmochloris), previously isolated as novel biodiesel feedstocks, were bioprospected for high-value, bioactive molecules. Methanol extracts were thus prepared from freeze-dried biomass and screened for different biological activities. Nannochloris sp. SBL1 and Desmochloris sp. SBL3 had the highest radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl, and the best copper and iron chelating activities. All species had potent butyrylcholinesterase inhibitory activity (>50%) and mildly inhibited tyrosinase. Picochlorum sp. SBL2 and Nannochloris sp. SBL4 extracts significantly reduced the viability of tumoral (HepG2 and HeLa) cells with lower toxicity against the non-tumoral murine stromal (S17) cells. Nannochloris sp. SBL1 significantly reduced the viability of Leishmania infantum down to 62% (250 mu g/mL). Picochlorum sp. SBL2 had the highest total phenolic content, the major phenolic compounds identified being salicylic, coumaric and gallic acids. Neoxanthin, violaxanthin, zeaxanthin, lutein and -carotene were identified in the extracts of all strains, while canthaxanthin was only identified in Picochlorum sp. SBL2. Taken together, these results strongly suggest that the microalgae included in this work could be used as sources of added-value products that could be used to upgrade the final biomass value.National Science, Technology and Innovation Program of King Abdulaziz Medical City for Science and Technology, Riyadh, Saudi Arabia [NPST, 11-ENE 1719-02]; Foundation for Science and Technology (FCT), Portugal [SFRH/BD/78062/2011]; FCT [IF/00049/2012, SFRH/BPD/86071/2012, Pest-OE/QUI/UI0612/2013]info:eu-repo/semantics/publishedVersio

    Consequences of marine barriers for genetic diversity of the coral-specialist yellowbar angelfish from the Northwestern Indian Ocean

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    Ocean circulation, geological history, geographic distance, and seascape heterogeneity play an important role in phylogeography of coral‐dependent fishes. Here, we investigate potential genetic population structure within the yellowbar angelfish (Pomacanthus maculosus) across the Northwestern Indian Ocean (NIO). We then discuss our results with respect to the above abiotic features in order to understand the contemporary distribution of genetic diversity of the species. To do so, restriction site‐associated DNA sequencing (RAD‐seq) was utilized to carry out population genetic analyses on P. maculosus sampled throughout the species’ distributional range. First, genetic data were correlated to geographic and environmental distances, and tested for isolation‐by‐distance and isolation‐by‐environment, respectively, by applying the Mantel test. Secondly, we used distance‐based and model‐based methods for clustering genetic data. Our results suggest the presence of two putative barriers to dispersal; one off the southern coast of the Arabian Peninsula and the other off northern Somalia, which together create three genetic subdivisions of P. maculosus within the NIO. Around the Arabian Peninsula, one genetic cluster was associated with the Red Sea and the adjacent Gulf of Aden in the west, and another cluster was associated with the Arabian Gulf and the Sea of Oman in the east. Individuals sampled in Kenya represented a third genetic cluster. The geographic locations of genetic discontinuities observed between genetic subdivisions coincide with the presence of substantial upwelling systems, as well as habitat discontinuity. Our findings shed light on the origin and maintenance of genetic patterns in a common coral reef fish inhabiting the NIO, and reinforce the hypothesis that the evolution of marine fish species in this region has likely been shaped by multiple vicariance events.This work was conducted within the framework of the NPRP project ‘Connectivity, diversity and genetic between offshore natural coral reefs and oil platforms – NPRP No. 7‐1129‐1‐201’, funded by the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the authors. F.T. is supported by a CNPq/Brazil fellowship through the program Science without Borders (Proc. 232875/2014‐6). We are also grateful to Filipe Vieira (University of Copenhagen) for his advice on population genetic analyses

    Novel composite materials of modified roasted date pits using ferrocyanides for the recovery of lithium ions from seawater reverse osmosis brine

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    In this paper, novel composite materials from modified roasted date pits using ferrocyanides were developed and investigated for the recovery of lithium ions (Li+) from seawater reverse osmosis (RO) brine. Two composite materials were prepared from roasted date pits (RDP) as supporting material, namely potassium copper hexacyanoferrate-date pits composite (RDP-FC-Cu), and potassium nickel hexacyanoferrate-date pits composite (RDP-FC-Ni). The physiochemical characterization of the RO brine revealed that it contained a variety of metals and salts such as strontium, zinc, lithium, and sodium chlorides. RDP-FC-Cu and RDP-FC-Ni exhibited enhanced chemical and physical characteristics than RDP. The optimum pH, which attained the highest adsorption removal (%) for all adsorbents, was at pH 6. In addition, the highest adsorption capacities for the adsorbents were observed at the initial lithium concentration of 100 mg/L. The BET surface area analysis confirmed the increase in the total surface area of the prepared composites from 2.518 m2/g for RDP to 4.758 m2/g for RDP-FC-Cu and 5.262 m2/g for RDP-FC-Ni. A strong sharp infrared peak appeared for the RDP-FC-Cu and RDP-FC-Ni at 2078 cm−1. This peak corresponds to the C≡N bond, which indicates the presence of potassium hexacyanoferrate, K4[Fe(CN)6]. The adsorption removal of lithium at a variety of pH ranges was the highest for RDP-FC-Cu followed by RDP-FC-Ni and RDP. The continuous increase in the adsorption capacity for lithium with increasing initial lithium concentrations was also observed. This could be mainly attributed to enhance and increased lithium mass transfer onto the available adsorption active sites on the adsorbents’ surface. The differences in the adsorption in terms of percent adsorption removal were clear and significant between the three adsorbents (P value < 0.05). All adsorbents in the study showed a high lithium desorption percentage as high as 99%. Both composites achieved full recoveries of lithium from the RO brine sample despite the presence of various other competing ions.This work was made possible by Qatar University collaborative internal grant # [QUCG-CAS-20/21-2]. The findings achieved herein are solely the responsibility of the author[s]

    Diet and feeding intensity of sardine Sardina pilchardus: correlation with satellite-derived chlorophyll data

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    Spatio-temporal variability of the diet of sardine Sardina pilchardus off Portugal was examined through analysis of the stomach contents of fish collected every 14 d from the west and south of Portugal during 2003/2004. Dietary composition of the modal sardine length class was assessed by determining the frequency of occurrence and carbon content of identified prey, and these 2 parameters were combined to estimate a modified index of relative importance of prey (mIRI). The most important prey for sardines were zooplankton, comprising crustacean eggs, copepods, decapods, cirripedes and fish eggs, dinoflagellates and diatoms (particularly the toxin-producer\ud genus Pseudo-nitzschia), which together accounted for >90% of the estimated dietary carbon. Dietary seasonality was similar for both areas, except that the contribution of phytoplankton was higher for fish from the west Portuguese coast, where upwelling events are stronger and recurrent during spring and summer months. The predominance of prey <750 μm in sardine diet suggests that filter feeding is the dominant feeding mode used in the wild. Feeding intensity was similar for both sexes and for fish of different length classes and was higher on the west coast than in the south, which is probably related to the higher productivity of the west coast. Although there was high inter-annual variability in feeding intensity, this parameter was highest for both areas during spring and winter months. Temporal variability in satellite-derived chlorophyll a matched the temporal variability in the dietary contribution by phytoplankton and of sardine feeding intensity, suggesting further investigation of the potential use of satellite-derived chlorophyll a data as a proxy for sardine feeding intensity

    Comparative study of shell shape and muscle scar pigmentation in the closely related cupped oysters Crassostrea angulata, C-gigas and their reciprocal hybrids

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    The taxonomic status of the cupped oysters Crassostrea angulata and C. gigas has received considerable attention in the last decades. Based on larval shell morphology, experimental hybridization, allozymes and nuclear DNA studies several authors have considered these two taxa as being synonymous. However, mitochondrial data showed clear genetic differences between the two taxa. In addition, microsatellite- based studies and cytogenetic studies have also provided evidence that supports their differentiation. Considerable differences have also been observed at the phenotypic level in terms of growth rate and ecophysiological parameters. In the present study, C. angulata from Sado estuary ( Portugal) and C. gigas from Seudre estuary ( France) were collected and factorial crosses were performed. Juveniles of the different progenies were reared in Ria Formosa ( Portugal) under common conditions to determine if they exhibited differences in shell shape and in pigmentation of the adductor muscle scar. Significant morphometric differences between C. angulata and C. gigas progenies were indicated by univariate and multivariate analyses. Univariate analysis of size- adjusted shell measurements revealed significant differences between the two taxa for shell depth, muscle scar height, and length of ligamental area. Both reciprocal hybrids showed intermediate morphometric characters between parental lines. In addition, significant differences were also observed between C. angulata and C. gigas progenies in terms of pigmentation of adductor muscle scar. C. angulata and both reciprocal hybrid progenies showed highly pigmented adductor muscle scars whereas in C. gigas progeny the pigmentation was lighter. The differences in shell shape and muscle scar pigmentation observed in the present study support the distinction of the two taxa.info:eu-repo/semantics/publishedVersio

    Marine climate change risks to biodiversity and society in the ROPME Sea Area

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    The subtropical ROPME Sea Area (RSA), comprising the Gulf, the Gulf of Oman and the northern Arabian Sea, is a heavily exploited sea region that experiences extreme environmental conditions, and for which climate change is expected to further impact marine ecosystems and coastal communities, sectors and industries. Climate change risk assessments provide a valuable tool to inform decision-making and adaptation planning through identifying and prioritising climate risks and/or opportunities. Using the first UK Climate Change Risk Assessment as an example, a marine climate change risk assessment was undertaken for the marine and coastal environment of the RSA for the first time. Through an extensive literature review and a workshop involving regional experts, marine and coastal climate change risks were identified, scored and prioritised. A total of 45 risks were identified, which spanned two key themes: ‘Risks to Biodiversity’ and ‘Risks to Economy and Society’. Of these, 13 were categorised as ‘severe’, including degradation of coral reefs and their associated ecological assemblages, shifts in the distribution of wild-capture fisheries resources, changes to phytoplankton primary productivity, impacts on coastal communities, threats to infrastructure and industries, and impacts on operations and safety in maritime transport. The diversity of risks identified and their transboundary nature highlight that climate change adaptation responses will require coordinated action and cooperation at multiple scales across the RSA. This risk assessment provides a crucial baseline for a largely overlooked geographic area, that can be used to underpin future decision-making and adaptation planning on climate change, and serve as a ‘blueprint’ for similar assessments for other regional shared seas

    H. Ben-Abdallah, Faculté des Sciences Economiques et de Gestion de Sfax

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    Object-oriented frameworks offer reuse at a high design level promising several benefits to the development of complex systems. However, framework design remains a difficult task due to the generality and variability frameworks must encompass. In addition, traditional object-oriented design methods only deal with the design of specific applications and do not facilitate the design of frameworks. In this paper, we present a UML-based framework design method called FBDM. The method offers a design language, called F-UML, and a semi-automatic design process both of which supported by a CASE environment. The design language F-UML visually distinguishes among the fixed components and the adaptable components of a framework. The design process for F-UML is based on stepwise, bottom-up unification rules that apply a set of comparison criteria on various applications in the framework domain. The design method is illustrated and evaluated through the design of a framework for electronic commerce brokers.

    Proposition et test de descripteurs pour l'identification de personnes dans un réseau de caméras

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    National audienceCe papier propose un descripteur basé sur les histogrammes régionaux fusionnant des caractéristiques intra et inters personnes pour faire l'indentification des piétons. Une étude comparative entre le descripteur proposé avec les principaux vecteurs caractéristiques de la littérature montre clairement que le vecteur proposé est capable d'identifier les personnes en multi caméras face à la nature très articulée du corps humain, à la variation de la pose, à la variation des conditions d'éclairages, à la variation d'échelle, à la variation de points de vue et face aux occultations partielles
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