bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelos probabilísticos de los contenidos porcentuales de pérdida al fuego, residuo insoluble y SO3 de cementos P-350 fabricados en España
Authors: Salcedo Martínez Fernando , Arteaga Iriarte Ángel
Published: July 2012

Limits fixed in Codes for the chemical characteristics of cements have been established with semi-empirical methods, given the complexity of influencing phenomena, without correspondence between these values and the physico-chemical or mechanical properties as durability or strength. Knowledge of statistical distribution models allows to fix limits of acceptation or rejection, with criteria of frequencies, and dependence relationships among them.
In order to propose distribution models for the percentage of Ignition Loss, Insoluble Residuum and SO3, the values of the variables on 255 samples analysed at the Instituto E. Torroja during 10 years, have been studied. Dependences among variables, defined by the correlation coefficients, have been studied as well. Sample values have been grouped in equally probable intervals and goodness of fit with Normal, Gamma and Log-Normal distributions was done by means of test X2. Finally, goodness of fit and agreement between upper fractals and maxima values in samples let us propose distribution models for each variable.
Bases para la interpretación de los resultados de la pérdida al fuego, SO3 y residuo insoluble
Authors: Triviño Vázquez F.
Published: July 2012

In this work, and interpretation of results of the chemistry analisys of the I.R., I. L. and SO3 in portland cements, is presented.
Primera consulta sobre la industria de los materiales de la construcción organizada por ONUDI y UNCHS (HABITAT)
Authors: Salas Julián
Published: July 2012

This work, devoted to the First Consultation sponsored by ONUDI-UNCHS (HABITAT) relative to "Building Materials Industry", selects three different sides of it: the final version of the conclusions and recommendations prepared in Athens by the participants, the author personal answers, as a participant himself, to some questions elabored by the Consultation organizers as well as a brief account of the round tables held in the IETcc with some of the Latin American professionals who took part in the X Course of High Studies on Construction focused on this important event.
Thus the aim is to try to spread among the readers of spanish language the Athens recommendations on the industry development of building materials in developing countries.
Contribución al estudio de la resistencia química de los cementos. Comportamiento mecánico de un cemento portland resistente al yeso (1.ª Parte)
Authors: Gaspar-Tébar Demetrio , Sagrera-Moreno José Luis , Gonzales-Vila Victoriano
Published: July 2012

This study, first part of a work where an account of the evolution of the mechanical resistances of various series of mortar and concrete tests submitted to the action of different agressive solutions will be given, sets up the chemical resistant behaviour of a sulphate resistant portland cement (with a content calculated —Bogue— null of C3A, of 10,8% of C4AF and of 81,7% of C3S + C2S) against the CaSO4.2 H2O through the Le Chatelier-Anstett methods, and described in the ASTM C 452-73 and against the following agressive solutions: saturated solution calcium sulphate, Na2SO4 (2,1 g/l), MgSO4.7H2O (3,22 g/l), MgSO4.7 H2O (32,2 g/l), saturated of calcium sulphate + MgSO4.7H2O (3,22 g/l), saturated of calcium sulphate + MgSO4.7H2O (32,2g/l), Na2SO4 (3,5 g/l) + NaCl (20,0 g/l), artificial sea water and, also, filtered drinking water, through of the Wittekindt and Kock Steinegger methods, during diverse periods, which allowed to establish a classification, according to his behaviour, of the studied cement against those agressive solutions.
Análisis cuantitativo de cuarzo-alfa en mezclas de cemento portland anhidro y calcita sintética por difracción de rayos X con equipo Philips PW-1700
Authors: Sagrera-Moreno J. L.
Published: July 2012

In this article there are explained the necessary steps to make up a quantitative analysis of alpha-quartz applying the technique of rays X diffraction, in artificial mixtures of anhydrous portland cement and synthetic calcite, which contents are known.
Inductively coupled plasma emission spectrometry
Authors: Sánchez de Rojas M. Isabel , De Luxán M. Pilar , Frías Moisés
Published: July 2012

Inductively coupled plasma emission spectroscopy technique (ICP) raised as a step forward in traditional emission spectroscopy, has allowed the quantification, even from a trace, of the elements of a sample by means of the elimination of most of the chemical interferences.
In this paper, a view of the subject is given, introducing the reader to this technique through the consideration of the essential parts of the ICP system, of the way to proceed when a qualitative and quantitative analysis is to be carried out, and its possible applications, specially in hydraulic binders, which development will bring the opportunity for future researches.
On the corrosion of reinforcing steels in concrete in the presence of chlorides
Authors: Raharinaivo Andre , R. Genin Jean Marie
Published: July 2012

The purpose of this study is to give a scientific justification to some empirical results, in steel corrosion field, from concrete containing chlorides.
First, it appears that corrosion products on the steels, have different structures and natures in function of the chloride content would be inferior or superior to a characteristic value.
Second, the penetration of the chlorides in the concrete can be described by a simple Fick's diffusion law in the most frecuent cases. When cement has a high proportion of tricalcium aluminates and the concrete a small porosity, Fick's law cannot be applied.
Effect of cement type and cement proportion in the corrosion rate of rebars embedded in carbonated mortar
Authors: Alonso C. , Andrade C.
Published: July 2012

The inexistence of quantitative data on steel behaviour in carbonated mortar and concrete have driven us to carry out a serie of tests to know the kinetic of the corrosion rebars.
Polarization Resistance was the technique used to determine the corrosion rate of the rebars.
In the present tests a first study with mortar has been carried out to know the influence of the cement nature, its proportion and water-cement (W/c) ratio on the steel corrosion rate.
The results indicate that the type of cement has not a significant influence, non a systematic trend in the corrosion rate measured.
On the contrary the cement proportion seems to have a more important effect (the higher the cement dosage c/s, the lower the corrosion is).
Corrosion behaviour of steel during accelerated carbonation of solutions which simulate the pore concrete solution
Authors: Alonso C. , Andrade C.
Published: July 2012

In spite of the numerous studies carried out on carbonation of the concrete, very few data have been published on the mechanism of steel depassivation and the corrosion rates involved in this type of phenomenon. Also some uncertainties remain as to the chemical composition of the pore solution of a carbonated concrete.
Random behaviours related with the changes in the corrosion rate of steel during accelerated carbonation of cement mortars have suggested the need to study the process in a more simple medium which allows the isolation of the different parameters. Thus, saturated Ca(0H)2 -base solutions with different additions of KOH and NaOH have been used to simulate the real pore concrete solution.
In the present work, simultaneous changes in the pH value, corrosion potential and corrosion rate (measured by means of the determination of the Polarization Resistance) of steel roads have been monitored during accelerated carbonation produced by a constant flux through the solution of CO2 gas and/or air.
Free lime quantitative determination by X ray diffraction, on anhiydrous and dried cement
Authors: Sagrera J. L.
Published: July 2012

In manufactured cements, and concerning the quality control, the fast determination of the contents of free lime is a necessary step. The measurement of the content is made taking the net altitude of one peak of the DRX which, on each case, is peculiar to the compound to be determined.
So, a calibrating curve is drawn, using there synthetic samples prepared with original cement with addition of 1%, 3% and 5% in weight of calcium oxide prepared fusing at 1100 °C for two hours a Merkc precipitate calcium carbonate. This calibrating curve allows to know the free lime content in original cement, when the results obtained by X ray diffraction is carried to the calibrating curve.
Comportamiento de un cemento portland resistente a los sulfatos frente al agua desionizada y a disoluciones de sulfato de sodio y de sulfato de magnesio
Authors: Bermejo-Muñoz M. Francisca , Sagrera-Moreno José Luis , Gaspar-Tebar Demetrio
Published: July 2012

Not available
Characterization of backfill mortars used in different tunnels in Spain
Authors: Cavalaro S. , Aguado A.
Published: July 2012

The main objective of this paper is to compare typical backfill mortars used in Spanish tunnels to fill the annular void left between the lining and the ground by the TBM. Initially, a new experimental program is outlined using material corresponding to 6 mixes from 4 tunnels. The results obtained indicate a considerable difference in the density and in the rheological properties of the mixes tested. According to the estimations performed, this leads to a difference of up to 67% on the potency required from the pumps to inject the material. Furthermore, a correlation between the fine content and the rheological properties of the mix was observed. This correlation may be a practical tool to control and modify the performance of the mortars directly in the worksite.
Producción y dirección de tesis doctorales sobre publicidad en la universidad española (1971-2010)
Authors: Marcos Recio Juan Carlos , Martínez Pestaña María Jesús , Blasco López María Francisca
Published: August 2012

Este estudio analiza la producción y dirección de tesis doctorales sobre publicidad en las universidades españolas. No sólo en las universidades que cuentan con facultades de Comunicación o Información, sino en todas aquellas que cuentan con alguna tesis doctoral sobre el tema y cuyo director figura de forma expresa. Para ello, se ha trabajado con una producción total de 260 tesis doctorales durante un período que abarca desde la creación de la Licenciatura de Publicidad en la universidad española en 1971 hasta el año 2010. Para los diferentes análisis se han aplicado técnicas bibliométricas. En el análisis se prestó atención a la evolución de la producción anual de las tesis doctorales, la distribución de la producción en las universidades, y en las facultades y departamentos responsables de las tesis doctorales. Finalmente, se analizó la producción de los directores de las tesis; así como los niveles de colaboración o cooperación en la dirección. El número de directores asciende a doscientos catorce. Las tesis dirigidas por más de un director se elevan a 25.
On the Dynamic Mechanism of Developing Recycling Economy for Enterprises in China
Authors: Cheng Huiqiang , Du Xiang-Yun
Published: August 2012

Recycling economy, as a new type of development model and economic growth mode, will form a social resultant force in government promotion, enterprise entities and public participation. Thus, it is quite necessary to discuss on the economic behavior, development restriction and profit motive of the Government, enterprises and the public as the micro-economic entities. Especially in the process of current recycling economic development of China, the sticking point for further development and achievement of Chinese recycling economy lies so much on how to enhance the intrinsic dynamics of the enterprises for developing the recycling economy.
Gathering Under a Green Umbrella
Authors: Rushforth Richard , Phillips Chester F.
Published: August 2012

The Parasol Club is a student-run, collaborative group focusing on sustainable resource use at the University of Arizona (UA), especially rainwater harvesting. The group’s fundamental idea is that, as a land-grant university in an arid environment, UA should serve as a learning laboratory for the development and demonstration of techniques for sustainable use of water and energy. Parasol’s success is due largely to its collaborative model in which students work closely with facilities staff, faculty, and administrators to identify sites, gather materials and labor, and bring projects to fruition. Completed projects serve as a testament to the effectiveness of the collaborative model. As the group has demonstrated the power of institutional collaboration at the university, its circle has widened to include members of several academic departments, additional facilities staff, and university administrators. New campus projects are planned, and the group has extended its reach to work with Tucson primary schools and neighborhood organizations on rainwater harvesting projects. This paper discusses Parasol’s model as an example for collaborative infrastructure and project development at an institutional level.
Target Marketing and Ethics
Authors: Fogel Gyongyi K. , Lewis Lorinda F.
Published: August 2012

Marketing to a targeted minority can provide a competitive advantage for an organization. However, there are ethical and legal concerns that must be carefully evaluated. Youth, children, and protected minorities, including women and the elderly, are a high target of advertising because of the increasing importance of these segments in making purchasing decisions. Recent population and demographic factors continue to impact marketing to address minority marketing issues with careful attention to ethics and social responsibility. This paper examines ethical concerns of advertising, the use of animated spokes-characters, marketplace discrimination, misleading practices, ethical concerns in minority marketing, and related advertising regulations. The authors conclude with recommendations for future research and implications for advertising and marketing practice. Policy implications are made for socially responsible advertising and marketing.
Case Study Reclaimed the Greener Way
Authors: Kaliski John , Booker Queen
Published: August 2012

Thanks to the strategic priorities of the current federal administration, discussions about green management are a popular trend in the business community. Increasing efficiency, limiting energy consumption, and reducing waste internally as well as along the supply chain has been one way that managers have addressed “going green.” Some examples include front-to-back printing and stringent recycling efforts. For the lumber industry, going green is not as easy as changing how employees print or recycle plastic bottles, especially since one of the main resources in the lumber industry is wood. In this regard, the authors discuss a proposed supply chain model to reduce intra-process shipments, improve raw material acquisition and usage, and improve production yields through repurposing of the wood by-product created during the manufacture of reclaimed, wood-based products. The proposed model also suggests that entrepreneurial efforts could lead the way in innovating how wood by-products can be used to create disruptive methods that could lead to new wood based businesses.
XML in Library Cataloging Workflows
Authors: Han Myung-Ja , Cho Christine
Published: August 2012

Libraries have been trying hard to produce and aggregate resources in both print and digital formats, which need to be integrated into the library system to provide access to users. This chapter summarizes the rapidly changing cataloging and metadata processing workflows in libraries and discusses the increasing need of exploiting XML technologies, including XSLT, and how this technology can improve in bibliographic metadata creation and management, and resource sharing and aggregation. The chapter narrates the changing environments of metadata management, especially diverse metadata sources and standards, which requires the use of new information technologies in traditional cataloging workflows.
VuFind
Authors: Katz Demian , Nagy Andrew
Published: August 2012

Apache Solr, an open source Java-based search engine, forms the core of many Library 2.0 products. The use of an index in place of a relational database allows faster data retrieval along with key features like faceting and similarity analysis that are not practical in the previous generation of library software. The popular VuFind discovery tool was built to provide a library-friendly front-end for Solr’s powerful searching capabilities, and its development provides an informative case study on the use of Solr in a library setting. VuFind is just one of many library packages using Solr, and examples like Blacklight, Summon, and the eXtensible Catalog project show other possible approaches to its use.
XCVQ Testing, Evaluation and Discussion
Authors: Al-Hamadani Badya , Lu Joan
Published: August 2012

Since the testing and evaluation processes are part of SDM, this chapter illustrates the detailed testing of XCVQ and its ensuing evaluation. Because the XCVQ model consists of three main parts, XCVQ-C, XCVQ-D, and XCVQ-QP, the testing strategy will involve testing each stage on its own. This chapter describes the testing of the three parts of the XCVQ model.
Automatic Mapping of XML Documents into Relational Database
Authors: Dweib Ibrahim , Lu Joan
Published: August 2012

Extensible Markup Language (XML) nowadays is one of the most important standard media used for exchanging and representing data through the Internet. Storing, updating, and retrieving the huge amount of web services data such as XML is an attractive area of research for researchers and database vendors. In this chapter, the authors propose and develop a new mapping model, called MAXDOR, for storing, rebuilding, updating, and querying XML documents using a relational database without making use of any XML schemas in the mapping process. The model addressed the problem of solving the structural hole between ordered hierarchical XML and unordered tabular relational database to enable us to use relational database systems for storing, updating, and querying XML data. A multiple link list is used to maintain XML document structure, manage the process of updating document contents, and retrieve document contents efficiently. Experiments are done to evaluate MAXDOR model. MAXDOR will be compared with other well-known models available in the literature (Tatarinov et al., 2002) and (Torsten et al., 2004) using total expected value of rebuilding XML document execution time and insertion of token execution time.
State of the Art Technology
Authors: Dweib Ibrahim , Lu Joan
Published: August 2012

This chapter presents the state of the art approaches for storing and retrieving the XML documents from relational databases. Approaches are classified into schema-based mapping and schemaless-based mapping. It also discusses the solutions which are included in Database Management Systems such as SQL Server, Oracle, and DB2. The discussion addresses the issues of: rebuilding XML from RDBMS approaches, comparison of mapping approaches, and their advantages and disadvantages. The chapter concludes with the issues addressed.
MAXDOR Model
Authors: Dweib Ibrahim , Lu Joan
Published: August 2012

This chapter gives a full description of the proposed model introduced by the authors. The new model is called MAXDOR for mapping XML document into relational database. The description includes mathematical concepts that are used in this model, the labelling method used to label XML document and identify its content, and the design framework used to maintain the document structure, parent-child, ancestor-descendant, and siblings relations among document contents. It also presents a set of algorithms for mapping, reconstructing, updating, and retrieving XML documents
Conclusions and Further Research
Authors: Dweib Ibrahim , Lu Joan
Published: August 2012

In this chapter, the authors characterize a new model for mapping XML documents into relational database. The model examines the problem of solving the structural hole between ordered hierarchical XML and unordered tabular relational database to enable use of the relational database systems for storing, updating, and querying XML data. The authors introduce and implement a mapping system called MAXDOR to solve the problem.
Methods Employed
Authors: Pein Raoul Pascal , Lu Joan , Renz Wolfgang
Published: August 2012

This chapter points out certain technologies that are often applied in a CBIR system. A prototypical retrieval system has been developed in order to evaluate the research hypothesis. Following common principles of information hiding, the software is designed to have multiple layers of abstraction. The top layer needs to be user friendly and also has the task to translate human understandable concepts into machine readable commands. As every user has a different level of expertise, the interface complexity should be adapted accordingly.
A Rule-Based Approach to Model Business Process
Authors: Xue Gang , Wu Zhongwei , Zhang Kun , Yao Shaowen
Published: August 2012

Up to the present, the modeling of business process manly focuses on the flow-control perspective, regardless of the logic relationships between models. Although the value of business rules in business process modeling has been recognized by many organizations, it is not fully clear how business rules can be used to model business process models. Business rules are powerful representation forms that can potentially define the semantics of business process models and business vocabulary. This chapter is committed to model the business process based on SBVR, then use the method mentioned below to transform a plain text rule statement into BPMN files.
Throughput Modeling, Analysis, and Optimization in Cognitive Wireless Networks
Authors: Babaei Alireza , Agrawal Prathima , Jabbari Bijan
Published: August 2012

In cognitive wireless networks, secondary nodes are required to sense the spectrum and to be cognizant of their interference on the primary receiving nodes. In this chapter, the authors show that the throughputs in the primary and the secondary networks have an entangled relationship and need to be considered jointly for optimization. Assuming that the primary and secondary networks use ALOHA as their medium access control protocol, the chapter shows that the throughputs in primary and secondary networks are influenced by the choices of transmission attempt probabilities in both of these networks. Authors show that the interference constraint limits the feasible space of transmission probabilities over which these networks can optimize their throughputs. They propose a progressive transmission probability optimizations algorithm and show through simulation that the algorithm converges to the optimum values of throughput in few time slots. Future research directions and the application of the constrained game theory to the throughput optimization problem are also discussed.
Application of Fuzzy Logic Power Control for Cognitive Radio Networks
Authors: Mohammed Abbas , Rakus-Andersson Elisabeth , Kulesza Wlodek
Published: August 2012

In this chapter, the authors present the application of fuzzy logic for power control in spectrum sharing cognitive radio network. The investigated network consists of a pair of primary users (PUs) and a pair of cognitive radio users (CRs). In order to compute an optimal power scale for the CR link, a fuzzy-based optimal power control strategy is investigated based on the Mamdani fuzzy control model using two input variables: the PU’s signal-to-noise ratio (SNR) and PU’s interference channel gain (channel gain from the cognitive radio users to primary users). Applying the fuzzy-based optimal power control strategy, the desired quality of service (QoS) is assured on the PU link, and the efficiency of spectrum usage is also maximized on the CR link in the spectrum sharing network. In addition, the bit error rate (BER) is also improved as compared with the spectrum sharing network without power control.
QoS Scheduling with Opportunistic Spectrum Access for Multimedia
Authors: Polacek Pavol , Huang Chih-Wei
Published: August 2012

Thanks to the advances of multimedia application, mobile computing platform, and wireless communication technology, the research area has attracted serious attention in order to seamlessly provide interactive and ubiquitous user experience. To make it happen, the pursuit of higher system capacity in resource limited wireless networks is never-ending. Cognitive radio (CR) represents an exciting new communication paradigm with advantages on spectrum management so as to heighten channel utilization and capacity. The bandwidth demanding multimedia applications are excellent candidates to fully exploit the potential of CR. However, the research effort has been focused mainly on spectrum access while the application specific performance has been much less touched. The research considering both spectrum access and application data scheduling is emerging for maximal user experience. In this chapter, the authors first discuss advances in opportunistic spectrum access (OSA) strategies as well as multimedia QoS scheduling schemes, and then introduce the research trend on joint access and scheduling frameworks.
Cognitive Cooperation in Wireless Networks
Authors: Ong Eng Hwee , Khan Jamil Y.
Published: August 2012

In recent years, vertical handover (VHO) has been identified as the primary vehicle to provision seamless mobility and quality of service (QoS) transparency for end-user in composite network. This allows end-user to enjoy ubiquitous connectivity in the most efficient way, irrespective of time and place, commonly known as always best connected. In this chapter, the authors introduce the notion of cognitive cooperation as a means to provide optimized VHO opportunistically in order to exploit the inherent heterogeneity that exists within such composite network to improve radio resource usage. Through the cognitive cooperation, the chapter proposes a distributed load adaptation strategy (LAS) framework which exploits the benefits of joint optimization, particularly between link adaptation and load adaptation on-demand. The authors advocate that such synergetic interactions between the physical layer (PHY) and medium access control (MAC) layer have advantages over the PHY approach based only on link adaptation. Comprehensive performance analyses show that the LAS framework arbitrates a QoS-balanced system in which statistical QoS guarantee for multimedia traffic can be provisioned and overall system capacity can be maximized.
Fuzzy Systems for Spectrum Access, Mobility and Management for Cognitive Radios
Authors: Kaur Prabhjot , Uddin Moin , Khosla Arun
Published: August 2012

This chapter addresses the issues in air interface designs for Cognitive Radios. Fuzzy logic system is used as one of the soft computing techniques to learn to sub optimality and vagueness. Many good, simple, and quick fuzzy based solutions have been developed since few decades in many diverse domains. Through this chapter, the authors first discuss the significance and need of soft computing techniques in designing such solutions and then present fuzzy based solutions for spectrum access, mobility, and management. Hierarchical fuzzy systems have been used to get over to the problem of curse of dimensionality. The proposed solutions consider an architecture, similar to the one proposed by IEEE 802.22 working group, for spectrum sharing and management. Models have been designed using fuzzy logic toolbox in MATLAB, and the system performance is checked using SIMULINK.
Channel State Prediction in Cognitive Radio
Authors: Chen Zhe
Published: August 2012

Spectrum sensing is the cornerstone of cognitive radio, which detects the availability of a spectrum band for the current time. In theory, the result of spectrum sensing reflects the current channel state, which is the ideal case. However, according to the author’s measurements, hardware platforms can introduce a non-negligible time delay on the signal path, which undermines the accuracy of spectrum sensing. To reduce the negative impact of the hardware platform time delay, channel state prediction in cognitive radio is proposed and presented in this chapter. As examples, channel state prediction algorithms based on a modified hidden Markov model (HMM) are given and tested using recorded real-world data. Moreover, as a second stage, cooperative channel state prediction is also proposed and experimentally evaluated. The experimental results approve that channel state prediction in cognitive radio indeed helps improve the accuracy of spectrum sensing in practical cases.
RFID and Labor Management Systems Selection in the Logistics Industry
Authors: Tibus Cheryl A. , Brennan Linda L.
Published: August 2012

• Make a recommendation based on the evaluation, financial data, and other considerations.
Stimulation of thermal stability of α-amylase from Bacillus icheniformis ATCC 6346 by treating with cations
Authors: Vengadaramana A , Balakumar S , Arasaratnam V
Published: August 2012

α-Amylases (1,4-α-D-glucan glucanohydrolase; E.C.3.2.1.1) catalyze the cleavage of α-1,4-glucosidic linkages in starch, glycogen, and various oligosaccharides. Thermostable α-amylases from Bacillus species are of great industrial importance in the production of corn syrup or dextrose. In this study effect of different cations on the enhancement of stability of α-amylase from Bacillus licheniformis ATCC 6346 was examined. Optimal activity of the enzyme was at pH 7.0 and 85 °C. α-Amylase activity was strongly inhibited by Cu2+, Hg2+ and Mn2+ but less affected by Mg2+ and Ba2+. Ca2+ and Na+ stimulated the enzyme activity at 85 °C and at pH 7.0. Addition of 0.01 M Na+ enhanced the enzyme stability from 1-33% for 60 min at 85 °C and pH 7.0. With 0.1M Na+, 100 % of initial enzyme activity was retained for 150 min and 70 min at 60 °C and 70 °C, respectively and 88% activity was retained at 80 °C, at pH 7.0 for 60 min. In the presence of 1 mM Ca2+, no loss of activity was observed in 60 min, at 85 °C and pH 7.0. Combined addition of 1mM Ca2+ and 0.1 M Na+, retained 17.3 % of the enzyme activity for180 min. But the enzyme in the presence of 1 mM Ca2+ and 0.1 M Na+ separately, lost its total activity in 120 min and 90 min, respectively at 95 °C and pH 7.0. DOI: http://dx.doi.org/10.4038/cjsbs.v41i1.4536 Ceylon Journal of Science (Bio. Sci.) 41 (1): 35-44, 2012
Radiological Measurements of Dimensions of Acutely Ruptured Internal Carotid Artery Aneurysm: A Comparative Study between Computed Tomographic Angiography and Digital Subtraction Angiography
Authors: Wong George , Yu Simon C.H. , Poon Wai Sang
Published: August 2012

After aneurysmal subarachnoid hemorrhage, most center practices treatment modality selection based on size and geometry in computed tomographic angiography. However, the validity as compared to digital subtraction angiography (DSA) is not well studied. Twenty patients with ruptured internal carotid artery aneurysm were identified in a two-year period. Mean difference in measurements from 3D computed tomographic angiography (3D-CTA) and 3D-DSA were less than 1 mm and 3D-DSA measurement did not alter the decision to proceed for endovascular embolization. With modern multislice computed tomography technology, good quality 3D-CTA alone would be sufficient to make size and geometry assessment for treatment selection for patients with ruptured internal carotid artery aneurysm.
Ipilimumab Pharmacotherapy in Patients with Metastatic Melanoma
Authors: Jeter Joanne M. , Cranmer Lee D. , Hersh Evan M.
Published: July 2012

Immune augmentation with ipilimumab, an anti-CTLA-4 monoclonal antibody, has joined the ranks of approved immunologic agents for the treatment of metastatic melanoma. Phase III studies of ipilimumab in metastatic melanoma have demonstrated an overall survival advantage as compared to other approved and investigational therapies. However, the adverse effects associated with this medication are unique and often require management with steroids or other immunosuppressants. In addition, the time to response differs with ipilimumab as compared to traditional chemotherapy, and alternative means of assessment of response have been proposed. In this review, we will summarize the basic science of this treatment, its preclinical evaluation, and the clinical trials leading to its approval. We will also discuss the details regarding its use, assessment of response to this drug and other immune-related therapies, and further directions for investigation.
Molecular Characterization and Phylogenetic Analysis of Dengue Viruses Imported into Taiwan during 2008–2010
Authors: Huang Jyh-Hsiung , Su Chien-Ling , Yang Cheng-Fen , Liao Tsai-Ling , Hsu Tung-Chien , Chang Shu-Fen , Lin Chien-Chou , Shu Pei-Yun
Published: August 2012

We present our surveillance results on imported dengue cases in Taiwan during 2008–2010. A total of 734 imported dengue patients were identified. The travelers were arriving from 18 countries, including Southeast Asia, the Indian subcontinent, South Pacific islands, and Latin America. Gene sequences from 358 dengue virus (DENV) isolates were used to perform phylogenetic analyses, thus, providing an updated view of the geographic distribution and dynamic transmission of DENV strains circulating in these countries. Our results suggest that the DENV-1 genotype I and DENV-2 Cosmopolitan genotype comprise the predominant DENV strains circulating in Southeast Asian countries. The DENV-3 Genotype III strain was found to be newly emerging in several Southeast Asian countries, however, the Asian genotype 2 and the Asian/American genotype of DENV-2 strains appeared to be less prevalent in Southeast Asia. Furthermore, imported dengue viruses are representative of the overall patterns of serotype/genotype frequencies of dengue outbreaks that occurred in Taiwan.
Scrub Typhus among Pediatric Patients in Dambadeniya:A Base Hospital in Sri Lanka
Authors: De Silva Nalika , Wijesundara Sarojini , Liyanapathirana Veranja , Thevanesam Vasanthi , Stenos John
Published: August 2012

Data on pediatric scrub typhus is uncommon in Sri Lanka and other countries. The objective of this study was to identify the clinical features of patients with scrub typhus at a Base Hospital in Sri Lanka. Sixty patients presenting with suspected scrub typhus were included in the study. Their blood samples were tested for the presence of antibodies against rickettsioses using the reference method. Twenty patients had confirmed scrub typhus and 24 had possible scrub typhus. Their clinical features are discussed in this work.
Tolerability and efficacy of two synergistic ratios of oral morphine and oxycodone combinations versus morphine in patients with chronic noncancer pain
Authors: De la Iglesia, MD Felix A. , Pace, PhD Gary W. , Robinson, PhD Gary L. W. G. , Huang, MD, PhD Nuo-Yu , Stern, PhD Warren , Richards, MD, PhD Patricia
Published: August 2012

Objectives: Analgesic synergy and improved tolerability have been reported for flexible dose morphine and oxycodone combinations. This report describes two studies with similar double-blind, randomized, 7-day crossover designs (up to 7 days per arm) conducted to 1) explore the analgesic and safety benefit of fixed ratio of morphine (M) and oxycodone (O) combinations (MOX) and 2) define the optimal ratio for morphine and oxycodone combination.Setting: Clinical study centers in Australia.Patients: Patients with chronic noncancer pain.Intervention: Eligible patients were randomly assigned to receive flexible doses of either M or fixed ratio of MOX (M3:O2 in study A; M1:O2 in study B). The starting doses of M or MOX were the morphine equivalent doses (MEDs) converted from the analgesics received before entering double-blind treatment. At each crossover period, the doses were titrated to achieve analgesia at steady state, which was defined as when the same total daily dose (±10 percent) had been given consecutively for 3 days.Main outcome measure: The primary endpoint was the study medication dose (MED), which produced adequate pain control at steady state.Results: Analgesic synergy in MOX was observed in both studies. On an MED basis, 61.6 percent (study A, M:O = 3:2) or 46.8 percent (study B, M:O = 1:2) more MED were needed for M monotherapy to achieve steady-state pain control when compared with MOX. Patient tolerability profiles were also generally better in the MOX groups.Conclusion: A 3:2 or1:2 fixed ratio combination of morphine and oxycodone (MOX) produced analgesic synergy and a tolerability profile improvement in patients with chronic noncancer pain.
A comparative study on the effects of intrathecal morphine added to levobupivacaine for spinal anesthesia
Authors: Unlugenc, MD Hakki , Gunduz, MD Murat , Guzel, MD Baris , Isik, MD Geylan
Published: August 2012

Objective: In this prospective, randomized, double-blind, controlled study, we investigated the sensory, motor, and analgesic block characteristics of two different doses of morphine compared with saline when added to 0.5 percent levobupivacaine.Design: Prospective, randomized, double-blinded, controlled study.Setting: University hospital.Patients, Participants, Interventions: One hundred and twelve ASA I or II adult patients undergoing cesarean section with combined-spinal epidural anesthesia (CSEA) were randomly allocated to receive 0.5 mL of 0.9 percent sodium chloride in group S, 0.1 mg of morphine in group M1, or 0.2 mg of morphine in group M2 following 15 mg of isobaric spinal levobupivacaine 0.5 percent (3 mL).Main Outcome Measure(s): We recorded the following: onset and duration of sensory and motor block, duration of spinal anesthesia, time to first request for analgesia, and side effects.Results: The onset time of sensory block was significantly less in group M2 (3.5 ± 3 minutes) than S (4 ± 3 minutes; p < 0.003). Parturients given morphine had a significantly greater duration of analgesia (554 ± 350 minutes in group M1 and 879 ± 725 minutes in group M2) than the saline group (80 ± 70 minutes; p < 0.001). Similarly, the time to first request for analgesia was longer in groups M1 (582 ± 470 minutes) and M2 (917 ± 709 minutes) than in group S (92 ± 77 minutes; p < 0.001).Conclusion: In patients undergoing cesarean delivery with CSEA, adding intrathecal morphine (0.1 and 0.2 mg) to 15 mg of spinal levobupivacaine prolonged the duration of spinal analgesia and provided rapid onset of action and longer time to first analgesic request without causing any significant side effect compared to saline.
Tropospheric bromine chemistry: implications for present and pre-industrial ozone and mercury
Authors: Parrella J. P. , Jacob D. J. , Liang Q. , Zhang Y. , Mickley L. J. , Miller B. , Evans M. J. , Yang X. , Pyle J. A. , Theys N. , Van Roozendael M.
Published: August 2012

Abstract. We present a new model for the global tropospheric chemistry of inorganic bromine (Bry) coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM). Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone mixing ratios by <1–8 nmol mol−1 (6.5% globally), with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4%. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT) to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.
Retrieving aerosol in a cloudy environment: aerosol product availability as a function of spatial resolution
Authors: Remer L. A. , Mattoo S. , Levy R. C. , Heidinger A. , Pierce R. B. , Chin M.
Published: July 2012

Abstract. The challenge of using satellite observations to retrieve aerosol properties in a cloudy environment is to prevent contamination of the aerosol signal from clouds, while maintaining sufficient aerosol product yield to satisfy specific applications. We investigate aerosol retrieval availability at different instrument pixel resolutions using the standard MODIS aerosol cloud mask applied to MODIS data and supplemented with a new GOES-R cloud mask applied to GOES data for a domain covering North America and surrounding oceans. Aerosol product availability is not the same as the cloud free fraction and takes into account the techniques used in the MODIS algorithm to avoid clouds, reduce noise and maintain sufficient numbers of aerosol retrievals. The inherent spatial resolution of each instrument, 0.5×0.5 km for MODIS and 1×1 km for GOES, is systematically degraded to 1×1, 2×2, 1×4, 4×4 and 8×8 km resolutions and then analyzed as to how that degradation would affect the availability of an aerosol retrieval, assuming an aerosol product resolution at 8×8 km. The analysis is repeated, separately, for near-nadir pixels and those at larger view angles to investigate the effect of pixel growth at oblique angles on aerosol retrieval availability. The results show that as nominal pixel size increases, availability decreases until at 8×8 km 70% to 85% of the retrievals available at 0.5 km, nadir, have been lost. The effect at oblique angles is to further decrease availability over land but increase availability over ocean, because sun glint is found at near-nadir view angles. Finer resolution sensors (i.e., 1×1, 2×2 or even 1×4 km) will retrieve aerosols in partly cloudy scenes significantly more often than sensors with nadir views of 4×4 km or coarser. Large differences in the results of the two cloud masks designed for MODIS aerosol and GOES cloud products strongly reinforce that cloud masks must be developed with specific purposes in mind and that a generic cloud mask applied to an independent aerosol retrieval will likely fail.
Technical Note: Calibration device for the krypton hygrometer KH20
Authors: Foken T. , Falke H.
Published: August 2012

Abstract. A calibration device for krypton hygrometers (KH20, Campbell Scientific, Inc.) with variable path length is presented. This unit allows for in-situ calibrations of the krypton hygrometer, which is typically not very stable over time, during measuring campaigns. It was constructed mainly for application at high altitudes and low temperatures, where further improvements are needed to the IR-hygrometers which are normally used. The changing path length requires that a changing concentration of the absorber be simulated. Because oxygen absorbs more strongly than water vapour, the calibration is made against oxygen and transferred to water vapour. The design of the calibration instrument is made as one unit containing a stepper motor system, PC and humidity sensor. For the calibration, it is necessary to install the krypton hygrometer on this unit.
Natural events of anoxia and low respiration index in oligotrophic lakes of the Atlantic Tropical Forest
Authors: Marotta H. , Fontes M. L. S. , Petrucio M. M.
Published: August 2012

Abstract. Hypoxia is a well-recognized condition reducing biodiversity and increasing greenhouse gas emissions in aquatic ecosystems, especially under warmer temperatures of tropical waters. Anoxia is a natural event commonly intensified by human-induced organic inputs in inland waters. Here, we assessed the partial pressure of O2 (pO2) and CO2 (pCO2), and the ratio between them (represented by the respiration index, RI) in two oligotrophic lakes of the Atlantic Tropical Forest, encompassing dry and rainy seasons over 19 months. We formulated the hypothesis that thermal stratification events could be coupled to natural hypoxia in deep waters of both lakes. Our results indicated a persistence of CO2 emissions from these tropical lakes to the atmosphere, on average ± standard error (SE) of 17.4 mg C m−2 h−1 probably subsided by terrestrial C inputs from the forest. Additionally, the thermal stratification during the end of the dry season and the rainy summer was coupled to anoxic events and very low RI in deep waters, and to significantly higher pO2 and RI at the surface (about 20 000 μatm and 1.0, respectively). In contrast, the water mixing during dry seasons at the beginning of the winter was related to a strong destratification in pO2, pCO2 and RI in surface and deep waters, without reaching any anoxic conditions throughout the water column. These findings confirm our hypothesis, suggesting that lakes of the Atlantic Tropical Forest could be dynamic, but especially sensitive to organic inputs. Natural anoxic events indicate that tropical oligotrophic lakes might be highly influenced by human land uses, which increase organic discharges into the watershed.
Suspended sediment concentration – discharge relationships in the (sub) humid Ethiopian highlands
Authors: Guzman C. D. , Tilahun S. A. , Zegeye A. D. , Steenhuis T. S.
Published: July 2012

Abstract. Loss of top soil and subsequent filling up of reservoirs in much of the lands with variable relief in developing countries degrades environmental resources necessary for subsistence. In the Ethiopia highlands, sediment mobilization from rain-fed agricultural fields is one of the leading factors causing land degradation. Sediment rating curves, produced from long-term sediment concentration and discharge data, attempt to predict suspended sediment concentration variations that exhibit a distinct shift with the progression of the rainy season. In this paper, we calculate sediment rating curves and examine this shift in concentration for three watersheds in which rain-fed agriculture is practiced to differing extents. High sediment concentrations with low flows are found in the beginning of the rainy season of the semi-monsoonal climate, while high flows and low sediment concentrations occur at the end of the rainy season. Results show that a reasonable unique set of rating curves were obtained by separating biweekly data into early, mid, and late rainfall periods and by making adjustments for the ratio of plowed cropland. The shift from high to low concentrations suggests that diminishing sediment supply and dilution from greater base flow during the end of the rainfall period play important roles in characterizing changing sediment concentrations during the rainy season.