Segmentation and kinematics of the North America‐Caribbean plate boundary offshore Hispaniola

We explored the submarine portions of the Enriquillo–Plantain Garden Fault zone (EPGFZ) and the Septentrional–Oriente Fault zone (SOFZ) along the Northern Caribbean plate boundary using high‐resolution multibeam echo‐sounding and shallow seismic reflection. The bathymetric data shed light on poorly documented or previously unknown submarine fault zones running over 200 km between Haiti and Jamaica (EPGFZ) and 300 km between the Dominican Republic and Cuba (SOFZ). The primary plate‐boundary structures are a series of strike‐slip fault segments associated with pressure ridges, restraining bends, step overs and dogleg offsets indicating very active tectonics. Several distinct segments 50–100 km long cut across pre‐existing structures inherited from former tectonic regimes or bypass recent morphologies formed under the current strike‐slip regime. Along the most recent trace of the SOFZ, we measured a strike‐slip offset of 16.5 km, which indicates steady activity for the past ~1.8 Ma if its current GPS‐derived motion of 9.8 ± 2 mm a^?1 has remained stable during the entire Quaternary.     

Can Religion Account for Early Animal Domestications? A Critical Assessment of the Cultural Geographic Argument,Based on Near Eastern Archaeological Data*

Cultural geographers often ascribe early animal domestications to the spiritual propitiation practices of ancient peoples, an interpretation that is not widely shared. This paper evaluates the sacrifice theory against Near Eastern archaeological data and refutes the idea that ritual sacrifice could have induced the earliest animal domestications of the Near East. The earliest domestications were the outcome of essentially ecological and economic processes which later gave rise to the sacrificial practices referred to by cultural geographers.     

The future of containerization: perspectives from maritime and inland freight distribution

As containerization enters its peak growth years, its potential future developments over maritime and inland freight transport systems are being questioned. A series of issues can either further accelerate the adoption of containerization worldwide or, alternatively, could impose an upper limit to the extraordinary contribution that containers have implied for logistics systems and global commodity chains. These mainly include macro-economic, technical/operational and governance factors. Future containerization will be largely determined by interactions within and between four domains ranging from a functional to a spatial perspective. The logistical domain involves the functional organization of transport chains and their integration in supply chains. The transport domain involves the operation of transport services and intermodal operations. The infrastructural domain involves the provision and management of basic infrastructure for both links and nodes in the transport system. The locational domain relates to the geographical location of nodes and sites in the economic space and forms a basic element for their intrinsic accessibility in terms of centrality or intermediacy. It is underlined that the future of containerization will dominantly be shaped by inland transport systems.     

Radiants of the Leonids 1999 and 2001 Obtained by Lltv Systems Using Automatic Software Tools

Both amateur and professional meteor groups are more frequently using Low-Light level TV (LLTV) systems to record meteors. Double-station observations can yield orbit data. However, data analysis normally is still done by hand and thus time consuming. This paper addresses the question of whether available automated tools can be used to determine reasonably accurate orbits with minimum human intervention. The European Space Agency performed several observing campaigns to observe the Leonid meteor stream. In November 1999, the ESA meteor group was stationed at two locations in Southern Spain, in November 2001 at two stations close to Broome in North-Western Australia. Double-station observations with LLTV systems were conducted. The data was recorded on S-VHS video tapes. The tapes were processed using automatic detection software from which meteor heights, velocities and radiants were computed. This paper shows the results for the two maximum nights. The radiants determined in 1999 show a very large scatter due to unfortunate observing geometry and inaccurate position determination since one of the cameras was moving because of the wind. The 2001 data is excellent and the radiant was determined to be at RA = 153.96°±0.3° and Dec = 21.09°±0.2°. The error bars for individual meteor radiants are about 0.2° to 0.4°. This demonstrates that is indeed possible to determine good radiant positions using totally automated tools. Orbits, on the other hand, are not well defined due to the fact that the velocity of individual meteors shows large errors. Reasons for this are described.     

A geostatistical re-interpretation of gravity surveys in the Yagoua,Cameroon region

Since 1960, many gravity studies have been carried out in the Yagoua region of northern Cameroon. Gravity data was collected over a wide area of approximately 11628 km². These data are insufficient, irregular, scattered and do not efficiently permit gravity field downward and upward continuations, derivatives and other operations that might require regular gridded data. Some anomalies on the Collignon map (1968), may correlate with known geological structure but do not appear on maps by Louis (1970) and Poudjom et al. (1996). To produce regular gridded gravity data and better control anomalies due to geological structures, the kriging method was applied to a 188-data baseline. Several variogram models were tested for this purpose. It was found that a spherical variogram model is the best; it has produced a new kriging dataset of about 10,100 data and a new map of kriged Bouguer data. This map contains positive anomalies in the Maroua-Mindif and Maga areas on the Collignon (1968) map, which were not present on Louis (1970) and Poudjom et al. (1996) maps. The positive anomalies of Guibi-Doukoula and Yagoua, not separated on the Louis (1970) and Poudjom et al. (1996) maps, show up as clearly distinct as previewed by Collignon (1968). The new results can be used for subsequent gravimetric studies.     

Geologic factors controlling groundwater chemistry in the coastal aquifer system of Douala/Cameroon: implication for groundwater system functioning

Douala city, located in the littoral province of Cameroon, receives abundant rainfall quantities due to its geographical position in the Gulf of Guinea and bears considerable surface water and groundwater resources. Due to socioeconomic development and rapid demographic growth in the city and its consequences of unplanned urbanization and improper sanitation system, these water resources are poorly protected and managed. Streams in the Wouri watershed receive large amounts of wastewater discharge, and hundreds of boreholes have been drilled into the aquifer system without any management plan. A detailed hydrodynamic and hydrogeochemistry study in Douala town and its environs was conducted to get a better insight into the groundwater system functioning in order to provide information for the sustainable management and protection of the groundwater resource. Two field campaigns were carried out with 187 samples collected and analyzed for major ions, stable isotopes (¹⁸O, ²H), and tritium ³H. The results of the sampling have shown that the weathering of silicate minerals is the dominant geochemical process affecting groundwater chemistry in this system. However, acid rainfall in the humid climate has also caused carbonate mineral dissolution, amorphous silica deposition, and ion exchange reactions to occur in aquifers in the region. The various water types identified were categorized into four major clusters C1 to C4, based on the major ion composition and the local hydrogeological conditions. Environmental isotope data reveal that modern-to-submodern waters occur in the phreatic Quaternary/Mio-Pliocene and Oligocene/Upper Eocene aquifers, respectively. These results corroborate with the conceptual model built where modern groundwater types indicated silicate mineral weathering and calcite dissolution (C1 and C2), whereas submodern groundwater mostly showed silica deposition, ion exchange, and, to a lesser extent, carbonate mineral dissolution (C3 and C4). This improved understanding of the aquifer system functioning is essential to provide a reasonable basis for effective control measures and sustainable water management.     

A reduced grid for a parallel global ocean general circulation model

A limitation of many global climate models with explicit finite-difference numerics is the timestep restriction caused by the decrease in cell size associated with the convergence of meridians near the poles. To keep the longitudinal width of model cells as uniform as possible, we apply a “reduced” grid to a three-dimensional primitive equation ocean-climate model. With this grid the number of cells in the longitudinal direction is reduced at high latitudes. The grid consists of subgrids which interact at interfaces along their northern and southern boundaries, where the resolution changes by a factor of three. We extend the finite-difference techniques to these interfaces, focusing on the conservation required to perform long time integrations, while preserving the staggered spatial arrangement of variables and the numerics used on subgrids. The common alternative used to reduce the timestep restriction caused by the spherical grid is the filtering of high-frequency modes from the high-latitude solution. The reduced grid allows an increased timestep while eliminating the need for filtering and reduces execution time per model step by roughly 20%. We implement the reduced grid model for parallel computer architectures with two-dimensional domain decomposition and message passing, with speedup results similar to those of the original model. We present results of model runs showing small effects on the solution and sizable improvements to the execution time.