River network rearrangements promote speciation in lowland Amazonian birds

Large Amazonian rivers impede dispersal for many species, but lowland river networks frequently rearrange, thereby altering the location and effectiveness of river-barriers through time. These rearrangements may promote biotic diversification by facilitating episodic allopatry and secondary contact among populations. We sequenced genome-wide markers to evaluate histories of divergence and introgression in six Amazonian avian species-complexes. We first tested the assumption that rivers are barriers for these taxa and found that even relatively small rivers facilitate divergence. We then tested whether species diverged with gene flow and recovered reticulate histories for all species, including one potential case of hybrid speciation. Our results support the hypothesis that river dynamics promote speciation and reveal that many rainforest taxa are micro-endemic, unrecognized and thus threatened with imminent extinction. We propose that Amazonian hyper-diversity originates in part from fine-scale barrier displacement processes, including river dynamics, which allow small populations to differentiate and disperse into secondary contact.

Modeling of oil phase displacement processes in heterogeneous anisotropic reservoirs

Methods of computer modeling of slightly permeable anisotropic oil-bearing layers are needed nowadays because they give us a possibility to obtain a concept on filtration processes near producing and forcing wells in different practical situations and in this way to raise the level of exploitation of such layers significantly. On the other hand, they allow evaluation and taking into account some uncertainties which appear as a result of inefficient information on the structure and properties of the layer outside the wells. In order to investigate the practical aspects of supporting efficiency of oil production in anisotropic heterogeneous low permeable reservoirs on the base of combined finite-element-difference method for solving the non-stationary anisotropic piezoconductivity problem, modeling of distribution of layer pressure was carried out in the vicinity of the production and forcing wells taking into account the anisotropy of the permeability and conditions of the oil phase infiltration on the margins of the examined layer. It has been found that the intensity of filtration process between producing and forcing wells depends essentially on their spacing in both shear-isotropic and anisotropic oil-bearing layers. In addition the effect of oil phase permeability in shear direction dominates over the effect of permeability in axes directions. Starting from the obtained information for the effective exploitation of anisotropic slightly permeable layers we need to locate producing and forcing wells in the areas with relatively low permeability of the layer and especially to avoid the places with presence of shear permeability. It is important to locate the wells in such a way that blocking the oil in the direction of reduced permeability and fast depletion of the layer in the direction of increased permeability would not happen as well as mutual exchange between producing and forcing wells would not stop. While locating the system of specified wells within anisotropic layers of oil deposit it is necessary to conduct a systemic analysis of environmental anisotropy of layers aimed at such a location of these wells which would guarantee the effective dynamics of filtration processes around them. Application of quadratic isoparametric approximation of finite-elemental net of examined area of oil-bearing layer and implicit differential time approximation brings to increase of precision and stability of numerical solution of the problem.

When Crime Moves Where Does It Go? Analyzing the Spatial Correlates of Robbery Incidents Displaced by a Place-based Policing Intervention

Objective: Examine the place-based correlates of robbery activity displaced by a foot-patrol intervention in Newark, NJ. We use constructs from Crime Pattern and Social Disorganization theories to test hypotheses concerned with associations between the structure of the environment and the displacement of crime. Method: Robbery incidents were spatially joined to street segments to study micro-level displacement processes. Predictor variables were operationalized using data from the Newark Police Department and Infogroup USA. Generalized Linear models tested associations between the characteristics of street segments and displaced robbery in the target area as compared to a control. Results: Environmental structure is important to understanding the settings of displacement, though this varied between spatial and temporal displacement. Relationships between displaced crime activity and model covariates did not always appear in expected directions. For example, bus stops predicted increased spatial displacement while corner stores predicted decreased levels of temporal displacement. Conclusions: While testing for displacement has become commonplace in place-based policing interventions, less attention has been paid to the micro-level factors that may facilitate the displacement of crime events. Both bus stops and corner stores show consistent associations with displaced crime activity, but the directions of these relationships suggest more complex processes requiring further examination.

Banana peel and mango kernel-based polymers and their suitability in enhanced oil recovery

This study reports the extraction and performance evaluation of two bio-derived polymers for enhanced oil recovery applications. The oil displacement processes were conducted using six (6) unconsolidated sandstone core plugs. Reservoir permeability tester was used to simulate real reservoir conditions in order to evaluate the suitability of the formulated biopolymers for oil displacement applications at laboratory conditions. The experimental results indicate the effectiveness of the biopolymer solutions in enhanced oil recovery in terms of their superior incremental oil recoveries after conventional waterflood with percentage oil recovery of 30.9–39.3% for banana peel derived polymer and 40.6–50.8% for mango kernel derived polymer compared to conventional waterflood with percentage recovery of 16.2–32% of the initial oil in place. This work identified the potential suitability and use of bio-derived polymers for enhanced oil recovery applications with emphasis on their biodegradability.

Evaluating the Effect of Oil-Displacing Agents Using Computer Graphics and Visualization Glass Plate Model Experiments

The results of visualization experiments primarily provide descriptions of local features or a general conclusion because, to obtain accurate numerical results, it is necessary to count each small point in the visual image and calculate the remaining oil based on the color. There is currently no method that can automatically and accurately calculate the recovery factor based on a visualized image. Computer graphics can be used to solve this problem, and Matlab software with its powerful image calculation functions was used to analyze and calculate images of visualization experiment processes. This article first summarizes the development and respective characteristics of the visual experiment evaluation of oil displacement agents. Then, the corresponding relationship between the actual oil displacement recovery parameters and the image parameters is introduced in detail, and a calculation formula for the visual image recovery factor is summarized. Finally, using the quantitative visual experimental results from different oil displacement agent injection methods as an example, we compared the different oil displacement processes and their recovery. The different characteristics of the two injection methods were evaluated, and the feasibility of the calculation method was verified. This method provides data support for interpreting visual experimental processes and a description of the experimental results. This provides a clear and unified calculation method for the recovery factors of oil displacement processes, which often involve many difficult-to-compare processes.