The discovery of an M4+T8.5 binary system     

Ben Burningham  D. J. Pinfield  S. K. Leggett  C. G. Tinney  M. C. Liu †  D. Homeier  A. A. West  A. Day-Jones  N. Huelamo  T. J. Dupuy  Z. Zhang  D. N. Murray  N. Lodieu  D. Barrado y Navascués  S. Folkes  M. C. Galvez-Ortiz  H. R. A. Jones  P. W. Lucas  M. Morales Calderon  M. Tamura 《Monthly notices of the Royal Astronomical Society》2009,395(3):1237-1248

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Evolution of hard gluons in a medium with q^(t)∼tn and the thermalization problem     

Felipe Gregoletto Ben  Magno V. T. Machado 《Astronomische Nachrichten》2024,345(2-3):e230186

We study the energy distribution of hard gluons traversing a dense quark-gluon plasma by comparing various transverse momentum broadening rates , using a probabilistic perturbative approach. These results were applied to address the thermalization problem in heavy ion collisions. Within the weak coupling model, thermalization follows a “bottom-up” process: early-formed high-energy partons emit low-energy gluons, leading to their equilibrium formation, creating a thermal bath that facilitates equilibrium in the high-energy sector. Under this scenario, we model the time dependencies of $$ as a power-law $$, and assess the impact of $$ on the distribution of hard gluons passing through the medium.  相似文献   

Change in the World City Network, 2000–2012     

Ben Derudder  Peter Taylor 《The Professional geographer》2016,68(4):624-637

This article presents a large-scale analysis of the trajectories of individual cities and regions in the world city network between 2000 and 2012. The methodology used to examine cities' evolving network centralities is based on advanced producer services firms “interlocking” cities through their worldwide distribution of offices. We do not limit our analysis to a limited set of putative world cities, but incorporate 157 cities from all world regions into this global urban analysis. Absolute and relative measures of change are developed to reveal the major dimensions of change. The most notable finding is that significant connectivity gains have been limited to a small set of cities (Dubai, Shanghai, Beijing, and Moscow in particular) in the face of persisting core–periphery patterns at the level of the global economy, with New York and London remaining firmly at the apex. At the same time, overall levels of connectivity in the world city network have clearly risen, suggesting an increasingly integrated network. In geographical terms, a west-to-east shift is discernible, albeit uneven.  相似文献   

A GIS-based soil erosion prediction using the Revised Universal Soil Loss Equation (RUSLE) (Lebna watershed,Cap Bon,Tunisia)     

Gaubi  I.  Chaabani  A.  Ben Mammou  A.  Hamza  M. H. 《Natural Hazards》2017,86(1):219-239

Natural Hazards - Soil erosion is a natural process causing grave land degradation problems. In Tunisia, soil erosion represents a serious environmental problem. Both man-made and natural...  相似文献   

Current runoff variations in the Macta catchment (Algeria): is climate the sole factor?     

Djelloul Baahmed  Ludovic Oudin  Mohamed Errih 《水文科学杂志》2015,60(7-8):1331-1339

Abstract

The first objective of this paper is to analyse the trends and change points in the hydroclimatic time series of five representative sub-catchments of the Macta basin, which lies in western Algeria. The second objective is to quantify the role of climate on the trends observed in annual flow time series. This is achieved using hydrological modelling at the multi-annual time step using the Schreiber formulation. The results showed no significant trends on annual rainfall in the 1975–2005 period, a significant increase of temperature and different flow responses to the latter, depending on the catchment considered. Two out of five catchments considered presented a significant flow decrease in the 1975–2005 period with a change point at the beginning of the 1990s. Modelling results suggest that the increase of air temperature is not the sole factor explaining the decrease of annual flow time series in these two catchments.  相似文献   

Seismic capacity of reinforced concrete interior flat plate connections     

Maged A. Youssef  Abu Obayed Chowdhury  Mohamed E. Meshaly 《Bulletin of Earthquake Engineering》2015,13(3):827-840

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New Visible‐Light Pt/PbS Nanoparticle Photocatalysts for the Photocatalytic Oxidation of Thiophene          下载免费PDF全文

Reda M. Mohamed  Elham S. Aazam 《洁净——土壤、空气、水》2015,43(3):421-426

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Sexual reproduction of Hippospongia communis (Lamarck, 1814) (Dictyoceratida,Demospongiae): comparison of two populations living under contrasting environmental conditions     

Souad Zarrouk  Alexander V. Ereskovsky  Karim Ben Mustapha  Amor El Abed  Thierry Pérez 《Marine Ecology》2013,34(4):432-442

The study of the reproductive processes of benthic invertebrates is essential to the understanding of their population dynamics and is also important in formulating conservation plans, especially for exploited species. The sexual reproduction of Hippospongia communis, the ‘honeycomb’ bath sponge, was studied at two locations in the Mediterranean Sea: the Kerkennah Islands (Tunisia, South Mediterranean), where the mean annual seawater temperature is 19 °C, and Marseille (France, Northwestern Mediterranean Sea), where the mean annual water temperature is 16 °C. The aim of this comparative study was to determine whether different environmental conditions could affect reproduction patterns. At both locations, H. communis was found to contain sexual reproductive elements year‐round. Oogenesis and embryogenesis occurred throughout the year, whereas spermatogenesis occurred during shorter periods between October and November, in both populations. While gametogenesis seemed to be synchronized, indicating that fertilization could occur at the same time at both locations, spawning was observed in late summer in Marseille, whereas it started in late spring for the Kerkennah population. Larval development of H. communis seems to take longer for sponges living at cooler locations such as Marseille. Reproductive effort calculated for both sexes showed significantly higher values for specimens from Kerkennah Islands. By comparing sexual reproductive patterns of populations living in two contrasted environments, we suggest that a change of thermal regime can affect H. communis phenology.  相似文献   

A review on 3D terrain visualization of GIS data: techniques and software     

Che Mat RUZINOOR  Abdul Rashid Mohamed SHARIFF  Biswajeet PRADHAN  Mahmud RODZI AHMAD  Mohd Shafry Mohd RAHIM 《地球空间信息科学学报》2012,15(2):105-115

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Advancing Global Marine Biogeography Research with Open‐source GIS Software and Cloud Computing     

Ei Fujioka  Edward Vanden Berghe  Ben Donnelly  Julio Castillo  Jesse Cleary  Chris Holmes  Sean McKnight  Patrick Halpin 《Transactions in GIS》2012,16(2):143-160

Across many scientific domains, the ability to aggregate disparate datasets enables more meaningful global analyses. Within marine biology, the Census of Marine Life served as the catalyst for such a global data aggregation effort. Under the Census framework, the Ocean Biogeographic Information System was established to coordinate an unprecedented aggregation of global marine biogeography data. The OBIS data system now contains 31.3 million observations, freely accessible through a geospatial portal. The challenges of storing, querying, disseminating, and mapping a global data collection of this complexity and magnitude are significant. In the face of declining performance and expanding feature requests, a redevelopment of the OBIS data system was undertaken. Following an Open Source philosophy, the OBIS technology stack was rebuilt using PostgreSQL, PostGIS, GeoServer and OpenLayers. This approach has markedly improved the performance and online user experience while maintaining a standards‐compliant and interoperable framework. Due to the distributed nature of the project and increasing needs for storage, scalability and deployment flexibility, the entire hardware and software stack was built on a Cloud Computing environment. The flexibility of the platform, combined with the power of the application stack, enabled rapid re‐development of the OBIS infrastructure, and ensured complete standards‐compliance.  相似文献