Maiter: An Asynchronous Graph Processing Framework for Delta-based Accumulative Iterative Computation

Myriad of graph-based algorithms in machine learning and data mining require parsing relational data iteratively. These algorithms are implemented in a large-scale distributed environment in order to scale to massive data sets. To accelerate these large-scale graph-based iterative computations, we propose delta-based accumulative iterative computation (DAIC). Different from traditional iterative computations, which iteratively update the result based on the result from the previous iteration, DAIC updates the result by accumulating the "changes" between iterations. By DAIC, we can process only the "changes" to avoid the negligible updates. Furthermore, we can perform DAIC asynchronously to bypass the high-cost synchronous barriers in heterogeneous distributed environments. Based on the DAIC model, we design and implement an asynchronous graph processing framework, Maiter. We evaluate Maiter on local cluster as well as on Amazon EC2 Cloud. The results show that Maiter achieves as much as 60x speedup over Hadoop and outperforms other state-of-the-art frameworks.Comment: ScienceCloud 2012, TKDE 201

Influence of Phosphorus Sources on the Compressive Strength and Microstructure of Ferronickel Slag-Based Magnesium Phosphate Cement

Electric furnace ferronickel slag (EFS) is a typical magnesium-rich industrial by-product discharged from the manufacture of nickel and iron-nickel alloys. The approach to use it as the raw material for the preparation of magnesium phosphate cement (MPC) has potential and proves effec-tive. In this study, three different phosphorus sources (PS) including phosphoric acid (H3 PO4, PA), sodium dihydrogen phosphate (NaH2 PO4, SDP) and potassium dihydrogen phosphate (KH2 PO4, PDP) were used to react with EFS to prepare the EFS-based MPC (EMPC), and the effects of raw material mass ratio (EFS/PA, EFS/SDP, EFS/PDP) on the compressive strength, early hydration temperature and microstructure of EMPC pastes were investigated. Results showed that the compressive strength of EMPC paste is significantly impacted by the type of phosphorus source and the raw materials mass ratio. When the EFS/PDP ratio is 4.0, the compressive strength of the MPC paste reaches up to 18.8, 22.8 and 27.5 MPa at 3, 7 and 28 d, respectively. Cattiite (Mg3 (PO4 )2·22H2 O), K-struvite (KMgPO4·6H2 O) and/or Na-struvite (NaMgPO4·6H2 O) were identified as the main hydration prod-ucts of EMPC. The development of EMPC mainly involves the dissolution of a phosphorus source, MgO and Mg2 SiO4, formation of hydration product as binder, and combination of the unreacted raw materials together by binders to build a compact form

Influence of Phosphorus Sources on the Compressive Strength and Microstructure of Ferronickel Slag-Based Magnesium Phosphate Cement

Electric furnace ferronickel slag (EFS) is a typical magnesium-rich industrial by-product discharged from the manufacture of nickel and iron-nickel alloys. The approach to use it as the raw material for the preparation of magnesium phosphate cement (MPC) has potential and proves effec-tive. In this study, three different phosphorus sources (PS) including phosphoric acid (H3PO4, PA), sodium dihydrogen phosphate (NaH2 PO4, SDP) and potassium dihydrogen phosphate (KH2 PO4, PDP) were used to react with EFS to prepare the EFS-based MPC (EMPC), and the effects of raw material mass ratio (EFS/PA, EFS/SDP, EFS/PDP) on the compressive strength, early hydration temperature and microstructure of EMPC pastes were investigated. Results showed that the compressive strength of EMPC paste is significantly impacted by the type of phosphorus source and the raw materials mass ratio. When the EFS/PDP ratio is 4.0, the compressive strength of the MPC paste reaches up to 18.8, 22.8 and 27.5 MPa at 3, 7 and 28 d, respectively. Cattiite (Mg3(PO4 )2·22H2 O), K-struvite (KMgPO4·6H2O) and/or Na-struvite (NaMgPO4·6H2O) were identified as the main hydration products of EMPC. The development of EMPC mainly involves the dissolution of a phosphorus source, MgO and Mg2SiO4, formation of hydration product as binder, and combination of the unreacted raw materials together by binders to build a compact form

A novel approach to inhibit HIV-1 infection and enhance lysis of HIV by a targeted activator of complement

<p>Abstract</p> <p>Background</p> <p>The complement system is one of the most potent weapons of innate immunity. It is not only a mechanism for direct protection against invading pathogens but it also interacts with the adaptive immunity to optimize the pathogen-specific humoral and cellular defense cascades in the body. Complement-mediated lysis of HIV is inefficient but the presence of HIV particles results in complement activation by the generation of many C3-fragments, such as C3dg and C3d. It has been demonstrated that activation of complement can enhance HIV infection through the binding of special complement receptor type 2 expression on the surface of mature B cells and follicular dendritic cells.</p> <p>Presentation of the hypothesis</p> <p>Previous studies have proven that the complement-mediated antibody-dependent enhancement of HIV infection is mediated by the association of complement receptor type 2 bound to the C3 fragment and deposited on the surface of HIV virions. Thus, we hypothesize that a new activator of complement, consisting of a target domain (C3-binding region of complement receptor type 2) linked to a complement-activating human IgG1 Fc domain (CR2-Fc), can target and amplify complement deposition on HIV virions and enhance the efficiency of HIV lysis.</p> <p>Testing the hypothesis</p> <p>Our hypothesis was tested using cell-free HIV-1 virions cultivated <it>in vitro </it>and assessment of virus opsonization was performed by incubating appropriate dilutions of virus with medium containing normal human serum and purified CR2-Fc proteins. As a control group, viruses were incubated with normal human serum under the same conditions. Virus neutralization assays were used to estimate the degree of CR2-Fc-enhanced lysis of HIV compared to untreated virus.</p> <p>Implications of the hypothesis</p> <p>The targeted complement activator, CR2-Fc, can be used as a novel approach to HIV therapy by abrogating the complement-enhanced HIV infection of cells.</p

Suitability evaluation for mountain-based adventure tourism: A case study of Xinjiang Tianshan, China.

In recent years, there has been considerable growth in the provision of and demand for adventure tourism; however, research that examines the resources regarding adventure tourism is limited. A spatial suitability evaluation system for mountain-based adventure tourism (MBAT) was developed via the integration of the AHP-Delphi technique. The evaluation system parameters included resource conditions, difficulty levels, safety conditions, and ecological sensitivity. Furthermore, each parameter contained several indicators that can be quantified and visualised in ArcGIS. The results showed that suitable areas for professional adventure tourism in Xinjiang Tianshan include the Kurdening and Tomur regions, and the those for adventure tourism include the Tianshan Tianchi lake. Furthermore, suitable areas for experiential adventure tourism include the Tianshan Tianchi lake, Tianshan Grand Canyon, Jiangbulak, East Tianshan, Tuohurasu scenic area, and the Gongliu wild fruit forest, while those for mass adventure tourism include large areas in the middle and low altitude range of Tianshan. The methods and results proposed in this paper are expected to be significant for planning adventure tourism and can be helpful for mountain communities when choosing regions to develop for adventure tourism, formulating tourism development strategies, increasing tourism opportunities, and thus improving regional competitiveness

Developing large-scale international ecological networks based on least-cost path analysis – a case study of Altai mountains

Habitat fragmentation and loss of landscape connectivity have resulted in the degradation of natural ecosystem services. Identifying international transboundary ecological network is an integrated approach to maintain regional ecological sustainability. In this study, taking Altai Mountains as a case study area, we suggested a set of procedures to construct an ecological network. First, we identified ecological patches by evaluating the values of the protected area. Second, we generated resistance surfaces based on the land cover characteristics. Third, we integrated habitat patches and resistance surfaces to identify potential corridors using the least-cost path analysis. The ecological network we introduced consists of 22 patches, 65 potential ecological corridors, and 5 stepping-stones. Furthermore, 26 ecological fragmentation points were marked. We proposed to carry out efficient and effective international cooperation between China, Russia, Kazakhstan, and Mongolia. In addition, the installation of road-crossing structures should be taken into consideration to minimize the negative impacts of the road-related disturbances