Analysis of symbiotic Symbiodinium in scleractinian corals off Northwestern Kish Island,Persian Gulf          下载免费PDF全文

Amirhossein Gheitanchi Mashini  Mona Fard Yazdani  Pargol Ghavam Mostafavi  Mohammad Hassan Shahhosseiny 《Marine Ecology》2017,38(2)

The genus Symbiodinium plays an essential role in the resistance and survival of reef‐building corals during temperature anomalies. Coral colonies inhabiting the Persian Gulf (PG) experience extended periods of different stresses. Kish Island is located in the harsh environment of the Northern PG with previously reported bleaching episodes. Samples of six coral species from Northwestern Kish Island were analysed by internal transcribed spacer 2 of ribosomal DNA to identify in hospite Symbiodinium populations. The results showed that lineage D of Symbiodinium was the most prevalent clade among different coral colonies, while clade C was only detected in symbiosis with a single coral species. However, the detected Symbiodinium subclades belonged to two host generalists. The predominance of the stress tolerant Symbiodinium trenchii and subclade C3 could suggest an acclimatization strategy to cope with the hostile environment of the PG.  相似文献   

Use of Posidonia Oceanica Ash in Stabilization of Expansive Soils     

Mona Malekzadeh  Huriye Bilsel 《Marine Georesources & Geotechnology》2013,31(2):179-186

Posidonia oceanica (PO) is the most plentiful seaweed of the Mediterranean Sea, which grows all along the coastal areas, forming widespread meadows. The leaf rejuvenation process of Posidonia oceanica typically occurs in fall when an increase in wave action causes the dead seaweeds to be transported and usually piled up along the coastal areas. This paper investigates the effect of PO ash stabilization on behaviour of an expansive clay. The ash was obtained by combustion of crushed PO pieces in a muffle furnace at 550°C. Atterberg limits, linear shrinkage, particle size distribution, one-dimensional swell, and unconfined compression tests have been carried out on natural soil as well as soil mixtures with 5% and 10% PO ash. There has been no significant improvement in the soil properties with 5% ash inclusion, whereas 10% ash has noticeably reduced the swell amount and increased the compressive strength. It is therefore concluded that there is a potential for the use of PO ash in geotechnical engineering applications.  相似文献   

Evaluating evapotranspiration using data mining instead of physical-based model in remote sensing     

Neissi  Lamya  Golabi  Mona  Albaji  Mohammad  Naseri  Abd Ali 《Theoretical and Applied Climatology》2022,147(1-2):701-716

Theoretical and Applied Climatology - Precise calculations for determining the water requirements of plants and the extent of evapotranspiration are crucial in determining the volume of water...  相似文献   

Detecting recent changes in the demographic parameters of drosophilid populations from western and central Africa     

Axelle Bouiges  Amir Yassin  Maya Ikogou  Clément Lelarge  Axelle-Rolande Sikoa  Stefano Mona  Michel Veuille 《Comptes Rendus Geoscience》2013,345(7-8):297-305

Previous genetic studies showing evidence of past demographic changes in African drosophilids suggested that these populations had strongly responded to Quaternary climate changes. We surveyed nine species of Zaprionus, a drosophilid genus mostly present in Africa, in forests located between southern Senegal and Gabon. The mitochondrial COI gene showed contrasted levels of sequence variation across species. Populations of the only cosmopolitan species of the genus, Z. indianus, and of its closely related sibling species, Z. africanus, are highly polymorphic and appear to have undergone a continuous population expansion beginning about 130,000 years ago. Five less variable species probably underwent a population expansion beginning only about 20,000–30,000 years ago. One of them, Z. taronus, was significantly structured between forest blocks. The last two species were nearly monomorphic, probably due to infection by Wolbachia. These results are similar to those obtained in three species from the melanogaster subgroup, and may be typical of the responses of African drosophilid populations to glacial cycles.  相似文献   

Deriving effects of pressure depletion on elastic framework moduli from sonic logs     

Anne-Kari Furre  Mona Andersen  Anita Smalø Moen  Randi Kristin Tønnessen 《Geophysical Prospecting》2009,57(3):427-437

We have developed a method to determine the effect of pore pressure depletion on elastic framework moduli, by utilizing sonic logs from wells drilled at different locations through a reservoir at varying depletion stages. This is done by first inverting the sonic logs for elastic framework bulk and shear moduli, thus carefully removing pressure dependent fluid effects. By crossplotting these elastic framework moduli against an increase in net stress (which is directly related to depletion), we derive the stress sensitivity of the elastic framework moduli. We found that the observed stress sensitivity was consistent with time-lapse seismic results and that the sensitivity derived from the sonic logs was much smaller than predicted by hydrostatic measurements on core samples. This method is applicable to depletion scenarios in mature fields and can be used both for modelling and inverting time-lapse seismic data for effects of pore pressure depletion on seismic data.  相似文献   

Unintentional Transgressions and Other Reflections on the Job Search Process     

Mona Domosh 《The Professional geographer》2000,52(4):703-708

In this article I examine connections between my past experiences on the academic job market and my research interests, particularly in regard to the notion of transgression. I offer my personal “story” of job seeking as a contribution to the dialogue concerning the relationships between personal lives and professional experiences, and as a case study of how considerations of merit can become clouded by personal and social discomfort with difference.  相似文献   

Evolutionary and flare-associated magnetic shear variations observed in a complex,flare-productive active region     

Ashok Ambastha  Mona J. Hagyard  E. A. West 《Solar physics》1993,148(2):277-299

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Measuring molecular variation in zooplankton populations: DNA extraction from smallDaphnia species     

Mona A. Mort  Bruno Streit 《Aquatic Sciences - Research Across Boundaries》1992,54(1):77-84

We present methods developed for the small-sizedDaphnia species,D. galeata, D. hyalina, D. cucullata, and their hybrids, which facilitate the use of DNA variation in population studies. Described are large-scale production of material from single genotypes ofDaphnia and subsequent extraction of total DNA. The average DNA yields ranged between 6 µg per gram wet weight (D. cucullata) and 12 µg per gram wet weight (D. galeata). For comparison, the large-sized speciesD. pulex was tested and yielded an average of 28 µg DNA per gram wet weight. The DNA isolated in this manner lends itself well to molecular genetic techniques suited for population studies.Reprint requests to B. Streit.  相似文献   

Design of sediment detention basins: Scaled model experiments and application     

Anita Moldenhauer-Roth  Guillaume Piton  Sebastian Schwindt  Mona Jafarnejad  Anton JSchleiss 《国际泥沙研究》2021,36(1):136-150

Sediment detention basins are implemented on mountain rivers to trap solid material that may aggravate the flooding of downstream settlements.However,retention structures built in the past may unnecessarily retain sediment during non-hazardous flood events,resulting in high maintenance costs and sediment deficit downstream.In addition,the so-called spontaneous self-flushing of previously retained sediment during floods has occasionally been observed.Recent research suggests to design sediment detention basins for controlling sediment passage with a guiding channel across the deposition area upstream of a hybrid barrier.Such barriers consist of a check dam with a slot orifice and an upstream bar screen with a bottom clearance in order to benefit from a combined mechanical-hydraulic retention control.The present paper enhances this pioneering research with the help of new experimental data,including a wide range of sediment mixtures and large wood,as well as variable barrier heights.Improved design criteria are provided regarding the bar screen and the basin storage capacity.The functionality of the enhanced concept for sediment detention is illustrated by a case study on a physical model:the protection of the Villard-Bonnot village(France)against torrential hazards.  相似文献   

Capture zone,travel time,and solute-transport predictions using inverse modeling and different geological models   总被引：2，自引：1，他引：1  

William?G.?HarrarEmail author  Torben?Obel?Sonnenborg  Hans?J?rgen?Henriksen 《Hydrogeology Journal》2003,11(5):536-548

Six regional-scale flow models are compared to gain insight into how different representations of hydraulic-conductivity distributions affect model calibration and predictions. Deterministic geological models were used to define hydraulic-conductivity distributions in two steady-state flow models that were calibrated to heads and baseflow estimates using inverse techniques. Optimized hydraulic-conductivity estimates from the two models were used to calculate layer and model mean hydraulic-conductivity values. Despite differences in the two geological models, inverse calibration produced mean hydraulic-conductivity values for the entire model domain that are quite similar. The layer and model mean hydraulic-conductivity values were used to generate four additional flow models and forward runs were performed. All of the models adequately simulate the observed heads and total baseflow. The six flow models were used to predict the steady-state impact of a proposed well field, and the flow solutions were used in simulating particle tracking and solute transport. Results of the predictive simulations show that, for this example, simple models of heterogeneity produce capture zones similar to more complex models, but with very different travel times and breakthroughs. Inverse modeling combined with different geological models can provide a measure of capture zone and breakthrough reliability.

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Resumen Se compara seis modelos de flujo a escala regional para conocer cómo afecta a la calibración y a la predicción del modelo diversas representaciones de la distribución de la conductividad hidráulica. Se ha utilizado modelos geológicos deterministas para definir las distribuciones de la conductividad hidráulica en dos modelos de flujo permanente, calibrados mediante técnicas inversas con niveles piezométricos y estimaciones del flujo de base. Se ha adoptado estimaciones optimizadas de la conductividad hidráulica de los dos modelos para calcular las cotas de las capas y sus conductividades hidráulicas medias. A pesar de las diferencias entre ambos modelos geológicos, con la calibración inversa se obtiene valores similares de conductividad hidráulica en todo el dominio. Estos valores de las capas y de las conductividades hidráulicas medias han servido para generar cuatro modelos adicionales de flujo y realizar predicciones. Todos los modelos simulan de forma adecuada los niveles observados y los caudales de base. Los seis modelos han sido aplicados a la predicción del impacto estacionario de un campo de pozos, y las soluciones del flujo permiten simular el transporte de partículas y de solutos. Los resultados de estas predicciones muestran que, para este ejemplo, los modelos sencillos de la heterogeneidad dan lugar a zonas de captura similares a las generadas por modelos más complejos, pero aparecen grandes diferencias en los tiempos de tránsito y en las curvas de llegada. Una combinación de modelación inversa y de modelos geológicos diferentes puede proporcionar una medida de la fiabilidad de la zona de captura y de las curvas de llegada.

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Résumé Six modèles d'écoulement à l'échelle régionale sont comparés afin d'avoir un aperçu de la manière dont les différentes représentations de la distribution de la conductivité hydraulique affectent la calibration et les prédictions de modèles. Des modèles géologiques déterministes ont été utilisés pour définir les distributions de la conductivité hydraulique dans deux modèles d'écoulement en régime permanent qui ont été calibrés avec des estimations des charges et des écoulements de base faites par des techniques inverses. Les estimations optimisées de la conductivité hydraulique de ces deux modèles ont servi à calculer les valeurs de conductivité hydraulique moyenne des couches et du modèle. Malgré des différences entre les deux modèles géologiques, la calibration inverse a donné des valeurs de conductivité hydraulique moyenne pour le domaine complet du modèle qui sont complètement semblables. Les valeurs de la conductivité moyenne des couches et du modèle ont été utilisées pour générer quatre modèles d'écoulement supplémentaires et des traitements ont été effectués. Tous les modèles simulent correctement les charges observées et l'écoulement de base total. Les six modèles ont servi à prédire l'impact en régime permanent d'un champ captant projeté et les solutions d'écoulement ont été utilisées dans une simulation par suivi de particules et de transport de soluté. Les résultats de simulations prédictives montrent que, pour cet exemple, de simples modèles d'hétérogénéité fournissent des zones de capture semblables aux modèles plus complexes, mais pour des temps de parcours et des restitutions très différents. Une modélisation inverse combinée à différents modèles géologiques peut assurer une mesure de la zone de capture et une fiabilité de la restitution.

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