bluuebunny/crossref_metadata_2025 huggingface dataset:
Global Access to Safe Water: Accounting for Water Quality and the Resulting Impact on MDG Progress
Authors: Onda Kyle , LoBuglio Joe , Bartram Jamie
Published: March 2012

Monitoring of progress towards the Millennium Development Goal (MDG) drinking water target relies on classification of water sources as “improved” or “unimproved” as an indicator for water safety. We adjust the current Joint Monitoring Programme (JMP) estimate by accounting for microbial water quality and sanitary risk using the only-nationally representative water quality data currently available, that from the WHO and UNICEF “Rapid Assessment of Drinking Water Quality”. A principal components analysis (PCA) of national environmental and development indicators was used to create models that predicted, for most countries, the proportions of piped and of other-improved water supplies that are faecally contaminated; and of these sources, the proportions that lack basic sanitary protection against contamination. We estimate that 1.8 billion people (28% of the global population) used unsafe water in 2010. The 2010 JMP estimate is that 783 million people (11%) use unimproved sources. Our estimates revise the 1990 baseline from 23% to 37%, and the target from 12% to 18%, resulting in a shortfall of 10% of the global population towards the MDG target in 2010. In contrast, using the indicator “use of an improved source” suggests that the MDG target for drinking-water has already been achieved. We estimate that an additional 1.2 billion (18%) use water from sources or systems with significant sanitary risks. While our estimate is imprecise, the magnitude of the estimate and the health and development implications suggest that greater attention is needed to better understand and manage drinking water safety.
Phenolic Contents and Compositions in Skins of Red Wine Grape Cultivars among Various Genetic Backgrounds and Originations
Authors: Zhu Lei , Zhang Yali , Lu Jiang
Published: March 2012

In order to analyze and compare the phenolic characteristics of red wine grapes with diverse genetic backgrounds, skin phenolics among 21 different cultivars belonging to Vitis vinifera L., East Asian and North American Vitis species and hybrids, as well as 2 varieties of muscadine grapes were estimated by HPLC-MS/MS. There were 45 anthocyanins, 28 flavonols, 8 flavan-3-ols, 9 cinnamic acids, 5 benzoic acids, 5 ellagic acids and 2 stilbenes detected in all the samples. Total contents of each phenolic type varied significantly among the different grape cultivars investigated. There was also a large variability in the phenolic compositions of different grape groups. The differences in anthocyanin composition were obvious between V. vinifera and non-V. vinifera grapes and also between the grapes originating from Eurasia and North America. Quercetin-3-glucuronide and quercetin-3-glucoside were marker flavonol compounds for Euvitis grape skins. Flavan-3-ol monomers were dominant in the skins of muscadine and non-V. amurensis East Asian grapes, whereas polymers were more common in V. vinifera and North American grapes. The muscadine grapes were very rich in flavonols, flavan-3-ols and ellagic acids. Via principal component analysis, these grape cultivars were clustered into three groups according to their characteristic phenolic content and composition.
A High Molar Extinction Coefficient Bisterpyridyl Homoleptic Ru(II) Complex with trans-2-Methyl-2-butenoic Acid Functionality: Potential Dye for Dye-Sensitized Solar Cells
Authors: Adeloye Adewale O. , Olomola Temitope O. , Adebayo Akinbulu I. , Ajibade Peter A.
Published: March 2012

In our continued efforts in the synthesis of ruthenium(II) polypyridine complexes as potential dyes for use in varied applications, such as the dye-sensitized solar cells (DSSCs), this work particularly describes the synthesis, absorption spectrum, redox behavior and luminescence properties of a new homoleptic ruthenium(II) complex bearing a simple trans-2-methyl-2-butenoic acid functionality as the anchoring ligand on terpyridine moiety. The functionalized terpyridine ligand: 4’-(trans-2-methyl-2-butenoic acid)-terpyridyl (L1) was synthesized by aryl bromide substitution on terpyridine in a basic reaction condition under palladium carbide catalysis. In particular, the photophysical and redox properties of the complex formulated as: bis-4’-(trans-2-methyl-2-butenoic acid)-terpyridyl ruthenium(II) bis-hexafluorophosphate [Ru(L1)2(PF6)2] are significantly better compared to those of [Ru(tpy)2]2+ and compare well with those of the best emitters of Ru(II) polypyridine family containing tridentate ligands. Reasons for the improved photophysical and redox properties of the complex may be attributed partly to the presence of a substituted α,β-unsaturated carboxylic acid moiety leading to increase in the length of π-conjugation bond thereby enhancing the MLCT-MC (Metal-to-ligand-charge transfer-metal centred) energy gap, and to the reduced difference between the minima of the excited and ground states potential energy surfaces.
Variation in Antioxidant Attributes at Three Ripening Stages of Guava (Psidium guajava L.) Fruit from Different Geographical Regions of Pakistan
Authors: Gull Javaria , Sultana Bushra , Anwar Farooq , Naseer Rehana , Ashraf Muhammad , Ashrafuzzaman M.
Published: March 2012

The present investigation was carried out to appraise the levels of total phenols and vitamin C as well as antioxidant potential at three different ripening stages (un-ripe, semi-ripe and fully-ripe) of guava (Psidium guajava L.) fruit collected from three different geographical regions of Pakistan (Islamabad, Faisalabad and Bhakkar). The antioxidant potential of guava fruit extracts was assessed by means of different in-vitro antioxidant assays, namely inhibition of peroxidation in linoleic acid system, reducing power and radical scavenging capability. Overall, fruit at the un-ripe stage (G1) exhibited the highest levels of TPC, TFC, reducing power and DPPH radical scavenging activity, followed by the semi-ripe (G2) and fully-ripe (G3) stages. On the other hand, vitamin C content increased as the fruit maturity progressed, with highest value seen at the fully-ripe stage (G3) followed by the semi-ripe (G2) and un-ripe stage (G1). The concentration of vitamin C in fruits varied as: Faisalabad (136.4–247.9 mg 100 g−1), Islamabad (89.7–149.7 mg 100 g−1) and Bhakkar (73.1–129.5 mg 100 g−1). The results showed that different stages of maturation and geographical locations had profound effects on the antioxidant activity and vitamin C contents of guava fruit.
Cancer Chemoprevention by Carotenoids
Authors: Tanaka Takuji , Shnimizu Masahito , Moriwaki Hisataka
Published: March 2012

Carotenoids are natural fat-soluble pigments that provide bright coloration to plants and animals. Dietary intake of carotenoids is inversely associated with the risk of a variety of cancers in different tissues. Preclinical studies have shown that some carotenoids have potent antitumor effects both in vitro and in vivo, suggesting potential preventive and/or therapeutic roles for the compounds. Since chemoprevention is one of the most important strategies in the control of cancer development, molecular mechanism-based cancer chemoprevention using carotenoids seems to be an attractive approach. Various carotenoids, such as β-carotene, a-carotene, lycopene, lutein, zeaxanthin, β-cryptoxanthin, fucoxanthin, canthaxanthin and astaxanthin, have been proven to have anti-carcinogenic activity in several tissues, although high doses of β-carotene failed to exhibit chemopreventive activity in clinical trials. In this review, cancer prevention using carotenoids are reviewed and the possible mechanisms of action are described.
Spectral Properties of Substituted Coumarins in Solution and Polymer Matrices
Authors: Donovalová Jana , Cigáň Marek , Stankovičová Henrieta , Gašpar Jan , Danko Martin , Gáplovský Anton , Hrdlovič Pavol
Published: March 2012

The absorption and fluorescence spectra of substituted coumarins (2-oxo-2H-chromenes) were investigated in solvents and in polymer matrices. The substitutions involved were: (1) by groups with varying electron donating ability such as CH3, OCH3 and N(CH3)2, mainly, but not exclusively, in positions 7 and (2), by either CHO or 4-PhNHCONHN=CH- in position 3. While the spectra of non-substituted coumarin-3-carbaldehyde has absorptions at approximately 305 and 350 nm, substitution at position 7 leads to remarkable changes in the shape of the absorption spectrum and shifts the absorption to a longer wavelength. Similarly, the replacement of the formyl group with a semicarbazide group substantially influences the shape of the absorption spectrum, and coumarins which have only N(CH3)2 in position 7 experience small changes. These changes are associated with the increasing intramolecular charge transfer (ICT) character and increasing conjugation length of the chromophoric system, respectively, in the studied molecules. The fluorescence is almost negligible for derivatives which have H in this position. With increasing electron donating ability, and the possibility of a positive mesomeric (+M) effect of the substituent in position 7 of the coumarin moiety, the fluorescence increases, and this increase is most intense when N(CH3)2 substitutes in this position, for both 3-substituted derivatives. Spectral measurements of the studied coumarins in polymer matrices revealed that the absorption and fluorescence maxima lay within the maxima for solvents, and that coumarins yield more intense fluorescence in polymer matrices than when they are in solution. The quantum yield of derivatives which have a dimethylamino group in position 7 in polymer matrices approaches 1, and the fluorescence lifetime is within the range of 0.5–4 ns. The high quantum yield of 7-dimethylamino derivatives qualifies them as laser dyes which have kF higher than knr in the given medium. This is caused by stiffening of the coumarin structure in polar polymer matrices, such as PMMA and PVC, due to higher micro-viscosity than in solution and intermolecular dipole-dipole interaction between chromophore (dopant) and matrix.
Antinociceptive and Anti-inflammatory Effects of a Lectin-Like Substance from Clitoria fairchildiana R. Howard Seeds
Authors: Leite Joana Filomena Magalhães , Assreuy Ana Maria Sampaio , Mota Mário Rogério Lima , Bringel Pedro Henrique de Souza Ferreira , E Lacerda Rodrigo Rodrigues , Gomes Vinícius de Morais , Cajazeiras João Batista , Do Nascimento Kyria Santiago , Pessôa Hilzeth de Luna Freire , Gadelha Carlos Alberto de Almeida , Delatorre Plinio , Cavada Benildo Sousa , Santi-Gadelha Tatiane
Published: March 2012

Lectins are proteins that have the ability to bind specifically and reversibly to carbohydrates and glycoconjugates, without altering the structure of the glycosyl ligand. They are found in organisms such as viruses, plants and humans, and they have been shown to possess important biological activities. The objective of this study was to purify and characterize lectins in the seeds of Clitoria fairchildiana, as well as to verify their biological activities. The results indicated the presence of a lectin (CFAL) in the glutelin acid protein fraction, which agglutinated native rabbit erythrocytes. CFAL was purified by column chromatography ion-exchange, DEAE-Sephacel, which was obtained from a peak of protein retained in the matrix by applying 0.5 M NaCl using the step-wise method. Electrophoretic analysis of this lectin in SDS-PAGE indicated a two band pattern protein molecular mass of approximately 100 and 116 kDa. CFAL proved to be unspecific to all carbohydrates/glycoconjugates in common use for the sugar inhibition test. This lectin showed no significant cytotoxicity to human red blood cells. It was observed that CFAL has anti-inflammatory activity in the paw edema induced by carrageenan model, in which a 64% diminution in edema was observed. Antinociceptive effects were observed for CFAL in the abdominal writhing test (induced by acetic acid), in which increasing doses of the lectin caused reduction in the number of contortions by up to 72%. It was concluded that the purified and characterized lectin from the seeds of Clitoria fairchildiana has anti-inflammatory and antinociceptive activity, and is not cytotoxic to human erythrocytes.
Antiproliferative, Antimicrobial and Apoptosis Inducing Effects of Compounds Isolated from Inula viscosa
Authors: Talib Wamidh H. , Zarga Musa H. Abu , Mahasneh Adel M.
Published: March 2012

The antiproliferative and antimicrobial effects of thirteen compounds isolated from Inula viscosa (L.) were tested in this study. The antiproliferative activity was tested against three cell lines using the MTT assay. The microdilution method was used to study the antimicrobial activity against two Gram positive bacteria, two Gram negative bacteria and one fungus. The apoptotic activity was determined using a TUNEL colorimetric assay. Scanning electron microscopy was used to study the morphological changes in treated cancer cells and bacteria. Antiproliferative activity was observed in four flavonoids (nepetin, 3,3′-di-O-methylquercetin, hispidulin, and 3-O-methylquercetin). 3,3′-di-O-Methylquercetin and 3-O-methylquercetin showed selective antiproliferative activity against MCF-7 cells, with IC50 values of 10.11 and 11.23 µg/mL, respectively. Both compounds exert their antiproliferative effect by inducing apoptosis as indicted by the presence of DNA fragmentation, nuclear condensation, and formation of apoptotic bodies in treated cancer cells. The antimicrobial effect of Inula viscosa were also noticed in 3,3′-di-O-methylquercetin and 3-O-methyquercetin that inhibited Bacillus cereus at MIC of 62.5 and 125 µg/mL, respectively. Salmonella typhimurium was inhibited by both compounds at MIC of 125 µg/mL. 3,3′-di-O-Methylquercetin induced damage in bacterial cell walls and cytoplasmic membranes. Methylated quercetins isolated from Inula viscosa have improved anticancer and antimicrobial properties compared with other flavonoids and are promising as potential anticancer and antimicrobial agents.
Salvianolic Acid A Inhibits PDGF-BB Induced Vascular Smooth Muscle Cell Migration and Proliferation While Does Not Constrain Endothelial Cell Proliferation and Nitric Oxide Biosynthesis
Authors: Sun Lan , Zhao Rui , Zhang Li , Zhang Tiantai , Xin Wenyu , Lan Xi , Huang Chao , Du Guanhua
Published: March 2012

Proliferation and migration of vascular smooth muscle cells (VSMCs) are critical events in the initiation and development of restenosis upon percutaneous transluminal coronary angioplasty (PTCA). Polyphenols have been suggested to ameliorate post-angioplasty restenosis. Salvianolic A (SalA) is one of the most abundant polyphenols extracted from salvia. In this study, we investigated the effect of salvianolic A (SalA) on the migration and proliferation of VSMCs. We found a preferential interaction of SalA with cellular systems that rely on the PDGF signal, but not on the EGF and bFGF signal. SalA inhibits PDGF-BB induced VSMC proliferation and migration in the concentration range from 0.01 to 0.1 μM. The inhibition of SalA on VSMC proliferation is associated with cell cycle arrest. We also found that SalA inhibits the PDGFRβ-ERK1/2 signaling cascade activated by PDGF-BB in VSMCs. In addition, SalA does not influence the proliferation of endothelial cells, the synthesis of NO and eNOS protein expression. Our results suggest that SalA inhibits migration and proliferation of VSMCs induced by PDGF-BB via the inhibition of the PDGFRβ-ERK1/2 cascade, but that it does not constrain endothelial cell proliferation and nitric oxide biosynthesis. Thus, the present study suggests a novel adjunct pharmacological strategy to prevent angioplasty-related restenosis.
A Voltage Mode Memristor Bridge Synaptic Circuit with Memristor Emulators
Authors: Sah Maheshwar Pd. , Yang Changju , Kim Hyongsuk , Chua Leon
Published: March 2012

A memristor bridge neural circuit which is able to perform signed synaptic weighting was proposed in our previous study, where the synaptic operation was verified via software simulation of the mathematical model of the HP memristor. This study is an extension of the previous work advancing toward the circuit implementation where the architecture of the memristor bridge synapse is built with memristor emulator circuits. In addition, a simple neural network which performs both synaptic weighting and summation is built by combining memristor emulators-based synapses and differential amplifier circuits. The feasibility of the memristor bridge neural circuit is verified via SPICE simulations.
Feline Immunodeficiency Virus in South America
Authors: Teixeira Bruno M. , Hagiwara Mitika K. , Cruz Juliano C. M. , Hosie Margaret J.
Published: March 2012

The rapid emergence of AIDS in humans during the period between 1980 and 2000 has led to extensive efforts to understand more fully similar etiologic agents of chronic and progressive acquired immunodeficiency disease in several mammalian species. Lentiviruses that have gene sequence homology with human immunodeficiency virus (HIV) have been found in different species (including sheep, goats, horses, cattle, cats, and several Old World monkey species). Lentiviruses, comprising a genus of the Retroviridae family, cause persistent infection that can lead to varying degrees of morbidity and mortality depending on the virus and the host species involved. Feline immunodeficiency virus (FIV) causes an immune system disease in domestic cats (Felis catus) involving depletion of the CD4+ population of T lymphocytes, increased susceptibility to opportunistic infections, and sometimes death. Viruses related to domestic cat FIV occur also in a variety of nondomestic felids. This is a brief overview of the current state of knowledge of this large and ancient group of viruses (FIVs) in South America.
Analysis of force-deconvolution methods in frequency-modulation atomic force microscopy
Authors: Welker Joachim , Illek Esther , Giessibl Franz J
Published: March 2012

In frequency-modulation atomic force microscopy the direct observable is the frequency shift of an oscillating cantilever in a force field. This frequency shift is not a direct measure of the actual force, and thus, to obtain the force, deconvolution methods are necessary. Two prominent methods proposed by Sader and Jarvis (Sader–Jarvis method) and Giessibl (matrix method) are investigated with respect to the deconvolution quality. Both methods show a nontrivial dependence of the deconvolution quality on the oscillation amplitude. The matrix method exhibits spikelike features originating from a numerical artifact. By interpolation of the data, the spikelike features can be circumvented. The Sader–Jarvis method has a continuous amplitude dependence showing two minima and one maximum, which is an inherent property of the deconvolution algorithm. The optimal deconvolution depends on the ratio of the amplitude and the characteristic decay length of the force for the Sader–Jarvis method. However, the matrix method generally provides the higher deconvolution quality.
Health-care providers’ preparedness for H1N1/09 influenza prevention and treatment in Dar es Salaam, Tanzania
Authors: Kamuhabwa Appolinary , Chavda Reena
Published: March 2012

Introduction: In Tanzania, the first case of H1N1/09 influenza was reported in September 2009.  By March 2010, the reported number of cases was 770 with one death.  Due to shortage of qualified human resources, essential medicines and laboratory supplies in health facilities, it was not known how well health-care providers in the country were prepared to deal with the pandemic. Methodology: The study was conducted from December 2009 to May 2010 in public hospitals and private community pharmacies in Dar es Salaam, Tanzania. Fifty-three prescribers and 200 dispensers were interviewed to assess their knowledge on the prevention and treatment of H1N1/09 influenza, and dissemination of correct information to the public regarding the pandemic. Results: Most participants had inadequate knowledge on the transmission, prevention and management of H1N1/09 influenza. The majority of prescribers knew neither the antiviral drugs recommended for the treatment of H1N1 influenza (64%) nor their adverse effects (92.5%). The drug dispensers' knowledge was also inadequate regarding the transmission, prevention and treatment of H1N1/09 influenza. Forty-one (20.5%) salespersons without formal training in pharmaceutical or medical sciences were found dispensing and supervising the pharmacies. Most participants had misconceptions on how H1N1/09 virus was transmitted. Conclusion: The results of the study revealed gaps in the knowledge of the health-care providers on the prevention and treatment of H1N1/09 influenza infection. This indicates the need for strengthening of health-care systems and provision of continuing education and professional development for health-care providers on new and re-emerging diseases in the community.
A probable association between HTLV-1 and endemic mycosis in Latin America
Authors: Leon Mey , Alave Jorge , Bustamante Beatriz , Gotuzzo Eduardo , Seas Carlos
Published: March 2012

This item has no abstract. Follow the links below to access the full text.
Facing the challenges of hepatitis B management in a developing country
Authors: Oluyemi Aderemi , Odeghe Emuobor
Published: March 2012

This item has no abstract. Follow the links below to access the full text.
El discurso de la innovación en tela de juicio: tecnología, mercado y bienestar humano
Authors: García José Luís
Published: March 2012

La tendencia principal de los estudios sociológicos de la innovación la asumen como algo positivo, sin distinguirse de los discursos políticos y económicos dominantes que la conciben como un fin en sí mismo o un medio al servicio de la producción económica y mercantil. Este artículo cuestiona tal visión y busca trazar los presupuestos y factores más importantes que explican la dinámica de la innovación en el marco de las transformaciones en curso en el mundo actual. Se sugiere un enfoque para los estudios sociales en que la innovación sea interpretada como acción social, dotada de fines, articulada a otras actividades de la vida humana y, por lo tanto, susceptible de valoraciones éticas y morales. Un enfoque de este tipo permitiría esclarecer el sentido social e histórico de los procesos de innovación y también entenderlos en el plano amplio de sus consecuencias imprevistas, riesgos e incertidumbres para la sociedad, la existencia humana y el ecosistema global.
Sistemas distrituales de innovación
Authors: Gabaldón Estevan Daniel , Fernández de Lucio Ignacio , Molina Morales Francesc Xavier
Published: March 2012

El concepto de sistema de innovación ha tenido un protagonismo creciente en el debate sobre los determinantes de la innovación y sus implicaciones en las políticas de innovación. El sistema de innovación identifica los agentes y sus interrelaciones en diferentes contextos: territorios, sectores o tecnologías y ha permitido un avance significativo en la comprensión de cómo funcionan los procesos innovadores. Sin embargo, frecuentemente el acotamiento puede no resultar el espacio en el que se desarrollan las relaciones más significativas para explicar los procesos de innovación. En nuestra propuesta, el Sistema Distritual de Innovación, tratamos de integrar la perspectiva sistémica y de aprendizaje a través de las interacciones provenientes de los sistemas de innovación con el concepto de distrito industrial, concepto ya consolidado que, si bien no ha considerado la innovación como un elemento clave, sí propone una delimitación del ámbito relacional que consideramos apropiada para el estudio de la innovación. Esta propuesta conceptual sugiere una serie de conclusiones e implicaciones relevantes en este debate sobre los procesos de innovación.
Tecnología y marketing: el papel de la retórica comercial en el desarrollo de dispositivos de navegación
Authors: Mendonça Pedro
Published: March 2012

Este artículo pretende relacionar tecnología y marketing en los procesos de imaginación y desarrollo de funcionalidades en dispositivos de navegación móvil. Se centra en la actuación de los departamentos empresariales de marketing, y de los trabajadores comerciales en general, como agentes retóricos que tienen un papel clave en los caminos técnicos de construcción del producto. En términos empíricos, se trata de un estudio de caso a una empresa portuguesa, Ndrive, que tiene como innovación principal la introducción de imagen fotográfica en los dispositivos de navegación, en vez de los tradicionales mapas. El campo de la innovación que se identifica es una plataforma donde se relacionan los dos ámbitos en cuestión (tecnología y marketing). Por ello, se utiliza la esfera teórica de los estudios de innovación para abordar el análisis de las diferentes problemáticas que van surgiendo en el desarrollo final del producto, muchas de ellas ligadas a las cuestiones centrales de la transformación tecnológica contemporánea.
Understanding science: when metaphors become terms
Authors: English Kathryn
Published: March 2012

La terminologie est une industrie de base dans la communication spécialisée. L’auteur examine l’interaction entre métaphores et termes techniques lors de l’apprentissage des concepts scientifiques, ainsi que les processus linguistiques de désignation des concepts nouveaux. Une sélection d’outils qui relève de la théorie de la métaphore : le cadre de présupposés, l’agrégation conceptuelle, les champs sources et les champs cibles est présentée. Deux outils de la terminologie, la description de concepts et la définition des termes ont pour but, au moins dans la théorie, de fournir des termes monosémiques dans un champ restreint.
Grid, P2P and SOA Orchestration
Authors: Pham Tran Vu , Lau Lydia M.S. , Dew Peter M
Published: March 2012

Supporting global scientific collaborations are becoming more important due to the increasing complexity of modern scientific problems as well as the need for sharing specialized expensive instruments and huge amount of data required for solving these problems. The combination of Grid computing and Web-based architecture has been a common technological architecture employed to address the need for an integrated environment for scientific collaborations. However, this approach is subjected to a certain level of centralized administration and control. This has been seen as inflexible and does not scale well with respect to the heterogeneity of distributed user communities. This chapter introduces an orchestration of P2P and Grid computing for supporting distributed scientific collaborations. In the resulted architecture, a P2P collaborative environment is used for heterogeneous users to collaborate and tap into large-scale computational resources and experimental datasets in the Grid computing environment. The service oriented architecture is used as a means of integrating these two environments.
Computational Grids
Authors: Hazin Ribhi , Qaddoumi Ibrahim , Pedrosa Francisco
Published: March 2012

A network of interconnected computers, or “computational grids,” can facilitate the ability of users to complete complex computational tasks that would be virtually impossible with a single computer. By leveraging the computational strength of grids, individual users can efficiently disseminate, exchange, and retrieve information as easily as if it were stored locally. As the authors found in this study, the possibilities computational grids present for highly specialized medical fields such as neuro-oncology are limitless. By harnessing the power of grids, neuro-oncologists can link to sophisticated interactive medical images around the world, perform complicated statistical analyses, create larger collaborative research projects, and improve delivery of care to patients around the globe. Thus, utilization of grid computing modules will inevitably lead to marked improvements in clinicians’ ability to detect, manage, and prevent complications associated with brain tumors.
Architectural Elements of Resource Sharing Networks
Authors: Dias de Assunção Marcos , Buyya Rajkumar
Published: March 2012

This chapter first presents taxonomies on approaches for resource allocation across resource sharing networks such as Grids. It then examines existing systems and classifies them under their architectures, operational models, support for the life-cycle of virtual organisations, and resource control techniques. Resource sharing networks have been established and used for various scientific applications over the last decade. The early ideas of Grid computing have foreseen a global and scalable network that would provide users with resources on demand. In spite of the extensive literature on resource allocation and scheduling across organisational boundaries, these resource sharing networks mostly work in isolation, thus contrasting with the original idea of Grid computing. Several efforts have been made towards providing architectures, mechanisms, policies and standards that may enable resource allocation across Grids. A survey and classification of these systems are relevant for the understanding of different approaches utilised for connecting resources across organisations and virtualisation techniques. In addition, a classification also sets the ground for future work on inter-operation of Grids.
Information Stewardship in Cloud Computing
Authors: Pym David , Sadler Martin
Published: March 2012

Cloud computing ecosystems of service providers and consumers will become a significant part of the way information services are provided, allowing more agile coalitions, cost savings and improved service delivery. Existing approaches to information security do not readily extend to this complex multi-party world. The authors argue for a mathematical model-based framework for the analysis and management of information stewardship that makes explicit both the expectations and responsibilities of cloud stakeholders and the design assumptions of systems. Such a framework supports integrated economic, technology, and behavioural analyses, so providing a basis for a better understanding of the interplay between preferences, policies, system design, regulations, and Service Level Agreements. The authors suggest approaches to constructing economic, technology, and behavioural models and discuss the challenges in integrating them.
Service Level Agreement (SLA) in Utility Computing Systems
Authors: Wu Linlin , Buyya Rajkumar
Published: March 2012

In recent years, extensive research has been conducted in the area of Service Level Agreement (SLA) for utility computing systems. An SLA is a formal contract used to guarantee that consumers’ service quality expectation can be achieved. In utility computing systems, the level of customer satisfaction is crucial, making SLAs significantly important in these environments. Fundamental issue is the management of SLAs, including SLA autonomy management or trade off among multiple Quality of Service (QoS) parameters. Many SLA languages and frameworks have been developed as solutions; however, there is no overall classification for these extensive works. Therefore, the aim of this chapter is to present a comprehensive survey of how SLAs are created, managed and used in utility computing environment. We discuss existing use cases from Grid and Cloud computing systems to identify the level of SLA realization in state-of-art systems and emerging challenges for future research.
Automatic Partitioning of Large Scale Simulation in Grid Computing for Run Time Reduction
Authors: Celik Nurcin , Mazhari Esfandyar , Canby John , Kazemi Omid , Sarfare Parag , Al-Otaibi Majed S. , Son Young-Jun
Published: March 2012

Simulating large-scale systems usually entails exhaustive computational powers and lengthy execution times. The goal of this research is to reduce execution time of large-scale simulations without sacrificing their accuracy by partitioning a monolithic model into multiple pieces automatically and executing them in a distributed computing environment. While this partitioning allows us to distribute required computational power to multiple computers, it creates a new challenge of synchronizing the partitioned models. In this article, a partitioning methodology based on a modified Prim’s algorithm is proposed to minimize the overall simulation execution time considering 1) internal computation in each of the partitioned models and 2) time synchronization between them. In addition, the authors seek to find the most advantageous number of partitioned models from the monolithic model by evaluating the tradeoff between reduced computations vs. increased time synchronization requirements. In this article, epoch- based synchronization is employed to synchronize logical times of the partitioned simulations, where an appropriate time interval is determined based on the off-line simulation analyses. A computational grid framework is employed for execution of the simulations partitioned by the proposed methodology. The experimental results reveal that the proposed approach reduces simulation execution time significantly while maintaining the accuracy as compared with the monolithic simulation execution approach.
An Autonomous Agent Approach to Query Optimization in Stream Grids
Authors: Mukherjee Saikat , Srinivasa Srinath , Ramamritham Krithi
Published: March 2012

Stream grids are wide-area grid computing environments that are fed by a set of stream data sources, and Queries arrive at the grid from users and applications external to the system. The kind of queries considered in this work is long-running continuous (LRC) queries, which are neither short-lived nor infinitely long lived. The queries are “open” from the grid perspective as the grid cannot control or predict the arrival of a query with time, location, required data and query revocations. Query optimization in such an environment has two major challenges, i.e., optimizing in a multi-query environment and continuous optimization, due to new query arrivals and revocations. As generating a globally optimal query plan is an intractable problem, this work explores the idea of emergent optimization where globally optimal query plans emerge as a result of local autonomous decisions taken by the grid nodes. Drawing concepts from evolutionary game theory, grid nodes are modeled as autonomous agents that seek to maximize a self-interest function using one of a set of different strategies. Grid nodes change strategies in response to variations in query arrival and revocation patterns, which is also autonomously decided by each grid node.
The Development of ICT for Envisioning Cloud Computing and Innovation in South Asia
Authors: Abu Sheikh Taher , Tsuji Masatsugu
Published: March 2012

This paper examines the implications of cloud computing in South Asia in relation to ICT deployment. The authors employ empirical analysis based on related literatures and an ICT panel dataset from 1999-2007, to discover significant factors in this field. Evidence from several studies has shown that the deployment of ICT is greatly related to improvements in a country’s economic performance. The study thus focuses on how ICT deployment helps South Asian countries to adopt cloud computing concepts and innovations, such as Web 2.0, Health 2.0 or Education 2.0. ICT penetration differs from country to country in several respects, except with regard to mobile phones. The study therefore generates new ideas, first, to increase capacity and add capabilities based on mobile technology to adopt the concepts of Web 2.0, Health 2.0 or Education 2.0 throughout South Asia, and, second, to re-think ICT deployment and encourage the diffusion of cloud computing and technological innovation. The paper concludes its analysis with suggestions for policy in developing countries.
A Service Component Model and Implementation for Institutional Repositories
Authors: Zhang Yong , Deng Quansong , Xing Chunxiao , Sun Yigang , Whitney Michael
Published: March 2012

With the boom of digital resources, there are urgent requirements to set up and manage Institutional Repositories (IRs) for companies and/or organizations. Cloud computing opens a new paradigm to build IRs by providing diverse services. We apply cloud services in the building of IRs and present a new model, which is based on digital object model and service component architecture, and consists of five service components, namely ID, metadata, content, log, and annotation service component. The five components are implemented by five corresponding clouds. These clouds provide two kinds of services: Web service and mashup service. We develop a framework and a code generation tool to generate an IR that can be used to manage the digital resources by invoking the five cloud services. Our approach is applied to the digital library on the history of water conservancy in China of Tsinghua University Library to demonstrate its feasibility.
A Push-Based Prefetching for Remote Caching RAM Grid
Authors: Chu Rui , Xiao Nong , Lu Xicheng
Published: March 2012

As an innovative grid computing technique for sharing the distributed memory resources in a high-speed wide-area network, RAM Grid exploits the distributed computing nodes, and provides remote memory for the user nodes which are short of memory. The performance of RAM Grid is constrained with the expensive network communication cost. In order to hide the latency of remote memory access and improve the performance, the authors proposed the push-based prefetching to enable the memory providers to push the potential useful pages to the user nodes. For each provider, it employs sequential pattern mining techniques, which adapts to the characteristics of memory page access sequences, on locating useful memory pages for prefetching. They have verified the effectiveness of the proposed method through trace-driven simulations.
Optimization Algorithms for Data Transfer in the Grid Environment
Authors: Xiong Muzhou , Jin Hai
Published: March 2012

In this chapter, two algorithms have been presented for supporting efficient data transfer in the Grid environment. From a node’s perspective, a multiple data transfer channel can be formed by selecting some other nodes as relays in data transfer. One algorithm requires the sender to be aware of the global connection information while another does not. Experimental results indicate that both algorithms can transfer data efficiently under various circumstances.
A QSQL-Based Service Collaboration Method for Automatic Service Composition, and Optimized Execution
Authors: Ren Kaijun , Chen Jinjun , Xiao Nong , Zhang Weimin , Song Junqiang
Published: March 2012

In scientific computing environments such as service grid environments, services are becoming basic collaboration components which can be used to construct a composition plan for scientists to resolve complex scientific problems. However, current service collaboration methods still suffer from low efficiency for automatically building composition plans because of the time-consuming ontology reasoning and incapability in effectively allocating resources to executing such plans. In this chapter, the authors present a QSQL-based collaboration method to support automatic service composition and optimized execution. With this method, for a given query, abstract composition plans can be created in an automatic, semantic, and efficient manner from QSQL (Quick Service Query List) which is dynamically built by previously processing semantic-related computing at service publication stage. Furthermore, concrete service execution instances can be dynamically bound to abstract service composition plans at runtime by comparing their different QoS(Quality of Service) values. Particularly, a concrete collaboration framework is proposed to support automatic service composition and execution. Totally, the authors’ proposed method will not only facilitate e-scientists quickly create composition plans from a large scale of service repository; but also make resource’s sharing more flexible. The final experiment has illustrated the effectiveness of their proposed method.
Overlay-Based Middleware for the Pervasive Grid
Authors: Grace Paul , Hughes Danny , Coulson Geoff , Blair Gordon S. , Porter Barry , Taiani Francois
Published: March 2012

Grid computing is becoming increasingly pervasive; sensor networks and mobile devices are now connected with traditional Grid infrastructure to form geographically diverse complex systems. Applications of this type can be classified as the Pervasive Grid. In this chapter we examine how traditional Grid technologies and middleware are inherently unsuited to address the challenges of extreme heterogeneity and fluctuating environmental conditions in these systems. We present Gridkit, a configurable and reconfigurable reflective middleware that leverages overlay networks and dynamic software in response to the requirements of the Pervasive Grid. We also illustrate how Gridkit has been used to deploy a flood monitoring application at a river in the north west of England; this demonstrates both the flexibility Gridkit provides, and how dynamic adaptation optimises performance and resource consumption.
Custom-Made Cloud Enterprise Architecture for Small Medium and Micro Enterprises
Authors: Mvelase Promise , Dlodlo Nomusa , Williams Quentin , Adigun Matthew O.
Published: March 2012

Small, Medium, and Micro enterprises (SMMEs) usually do not have adequate funds to acquire ICT infrastructure and often use cloud computing. In this paper, the authors discuss the implementation of virtual enterprises (VE) to enable SMMEs to respond quickly to customers’ demands and market opportunities. The virtual enterprise model is based on the ability to create temporary co-operations and realize the value of a short term business opportunity that the partners cannot fully capture on their own. The model of virtual enterprise is made possible through virtualisation technology, which is a building block of cloud computing. To achieve a common goal, enterprises integrate resources, organisational models, and process models. Through the virtual business operating environment offered by cloud computing, the SMMEs are able to increase productivity and gain competitive advantage due to the cost benefit incurred. In this paper, the authors propose a virtual enterprise enabled cloud enterprise architecture based on the concept of virtual enterprise at both business and technology levels. The business level comprises of organisational models, process models, skills, and competences whereas the technology level comprises of IT resources.
A Scalable Approach to Real-Time System Timing Analysis
Authors: Grigg Alan , Guan Lin
Published: March 2012

This chapter describes a real-time system performance analysis approach known as reservation-based analysis (RBA). The scalability of RBA is derived from an abstract (target-independent) representation of system software components, their timing and resource requirements and run-time scheduling policies. The RBA timing analysis framework provides an evolvable modeling solution that can be instigated in early stages of system design, long before the software and hardware components have been developed, and continually refined through successive stages of detailed design, implementation and testing. At each stage of refinement, the abstract model provides a set of best-case and worst-case timing ‘guarantees’ that will be delivered subject to a set of scheduling ‘obligations’ being met by the target system implementation. An abstract scheduling model, known as the rate-based execution model then provides an implementation reference model with which compliance will ensure that the imposed set of timing obligations will be met by the target system.
A Distributed Storage System for Archiving Broadcast Media Content
Authors: Cherry Dominic , Li Maozhen , Qi Man
Published: March 2012

This chapter presents MediaGrid, a distributed storage system for archiving broadcast media contents. MediaGrid utilizes storage resources donated by computing nodes running in a distributed computing environment. A genetic algorithm for resource selection is built in MediaGrid with the aim to optimize the utilization of resources available for archiving media files with various sizes. Evaluation results show the effectiveness of MediaGrid in archiving broadcast media contents, and the performance of the genetic algorithm in resource utilization optimization
Modeling Scalable Grid Information Services with Colored Petri Nets
Authors: Sahota Vijay , Li Maozhen , Hadjinicolaou Marios
Published: March 2012

Information services play a crucial role in grid computing environments in that the state information of a grid system can be used to facilitate the discovery of resources and services available to meet user requirements and help tune the performance of the grid. This paper models PIndex, which is a grouped peer-to-peer network with Colored Petri Nets (CPNs) for scalable grid information services. Based on the CPN model, a simulator is implemented for PIndex simulation and performance evaluation. The correctness of the simulator is further verified by comparing the results computed from the CPN model with the results generated by the PIndex simulator.
E-Portfolio to Promote the Virtual Learning Group Communities on the Grid
Authors: Gouardères Guy , Conté Emilie
Published: March 2012

In Vocational and Educational Training (VET), new trends are toward social learning and, more precisely, toward informal learning. In such settings, this article introduces a process — the e-Qualification — to manage informal learning on the ELeGI “Learning Grid Infrastructure.” It argues that this process must occur in a social context, such as virtual communities. On the one hand, it describes their necessary characteristics and proprieties that lead to the creation of a new kind of virtual community: the Virtual Learning Grid Community (VLGC). On the other hand, e-Qualification cannot occur without the help of a kind of user’s profile, called e-portfolio. Moreover, the e-portfolio is also a process, used to manage the Virtual Learning Grid Communities. The e-Qualification and Virtual Learning Grid Communities’ management will probably rely on the cooperation of different distributed, autonomous, goal-oriented entities, called Mobile Peer-to-Peer (P2P) Agents. Furthermore, we hope that implementing these services will decrease the lack of informal learning treatment on the grid and will become the basis for new services on the Learning Grid.
Accessing Grid Metadata through a Web Interface
Authors: Scifo Salvatore
Published: March 2012

This chapter focuses on the efforts to design and develop a standard pure Java API to access the metadata service of the EGEE Grid middleware, and provide at the same time a powerful object oriented framework to allow engineers and programmers to embed metadata features inside their own application, using a standard approach based on design patterns. A specific Web interface is built on top of this framework that permits users and administrators to manage the metadata catalog, from any platform and everywhere, according to their own X.509-based credentials.
High-Throughput GRID Computing for Life Sciences
Authors: De Sario Giulia , Tulipano Angelica , Donvito Giacinto , Maggi Giorgio , Gisel Andreas
Published: March 2012

The number of fully sequenced genomes increases daily, producing an exponential explosion of the sequence, annotation and metadata databases. Data analysis on a genome-wide level or investigation within a specific data repository has become a data- and calculation-intensive process occupying single computers and even larger computer clusters for month or even years. In most cases such applications can be subdivided into many independent smaller tasks. The smaller tasks are particularly suited to distribution over a computational GRID infrastructure, which drastically reduces the time to reach the final result. In our analysis of gene ontology data and their associations to gene products of any kind of organism in a search to find gene products with similar functionalities, we developed a system to divide the full search into a large number of jobs and to submit these jobs to the GRID infrastructure as long as all jobs are processed successfully, guaranteeing an analysis of the data without missing any information.