bluuebunny/crossref_metadata_2025 huggingface dataset:
Online Remote Control of a Wireless Home Automation Network
Authors: Wade John , Santos Jose , Evans Noel
Published: February 2011

Embedded systems within home appliances are not usually manufactured to operate in a networked environment; connecting supplementary hardware/software systems through a wireless, PC-controlled medium is necessary to enable full, efficient control of their functions from a remote location. Access to the home’s central PC may be gained via a local web server, giving Internet-based control from almost anywhere in the world. The proposed system constitutes a significant improvement over those discussed in the literature to date, and reviewed here. It enables complex-appliance control in a secure and reliable portable-wireless environment, and was developed using ASP.Net. The system was assessed for Received Signal Strength (RSS) in an environment more radio-hostile than that found in a typical household. The minimum RF level found at a transfer rate of 9.6 kbps was 8 dB above the receiver’s quoted sensitivity of -103 dBm; this fading margin will increase in a normal household environment.
Mining Parallel Patterns from Mobile Users
Authors: Goh John , Taniar David
Published: February 2011

Mobile technology is a widely adopted technology and is used for mobile users to stay connected. Mobile data mining is an extension of data mining for the purpose of developing innovative ways to extract useful knowledge out from mobile users to the decision makers. Our proposed method, parallel pattern, provides a method for finding out similar decisions by mobile users. Parallel patterns are divided into physical parallel pattern and logical parallel pattern. Physical parallel pattern finds the similarities of physical movement decisions among mobile users. Logical parallel pattern finds the logical similarities of logical theme movements among mobile users. In physical parallel pattern, mobile users can only occupy one physical location at any one time while in logical parallel pattern, mobile users can occupy more than one logical theme at any one time and each static node can have more than one logical theme at any one time. Our performance evaluation shows that the method for mobile parallel pattern mining suits for the real world problem in both the physical and logical parallel pattern mobile mining paradigm.
Wireless Data Broadcast Schemes for Location-Dependent Information Services Under a Geometric Location Model
Authors: Park KwangJin , Song MoonBae , Hwang Chong-Sun
Published: February 2011

Indexing techniques are used to implement selective tuning in wireless environments. Indices are broadcast together with data to help mobile clients locate the required information. As a result, clients stay in doze mode most of the time. The drawback of this solution is that broadcast cycles are lengthened due to additional index information. In this paper, we introduce the broadcast-based LDIS scheme (BBS) for the mobile computing environment. In the BBS, broadcasted data objects are sorted sequentially, based on their location, and the server broadcasts the location-dependent data (LDD) without additional indices. Then, we present a data prefetching scheme and OBC (Object Boundary Circle) in order to reduce the client’s tuning time. The performance of the proposed scheme is investigated in relation to various environmental variables, such as the distributions of the data objects, the average speed of the clients, and the size of the service area.
Risk Factors to Retrieve Anomaly Intrusion Information and Profile User Behavior
Authors: Wang Yun , Seidman Lee
Published: February 2011

The use of network traffic audit data for retrieving anomaly intrusion information and profiling user behavior has been studied previously, but the risk factors associated with attacks remain unclear. This study aimed to identify a set of robust risk factors via the bootstrap resampling and logistic regression modeling methods based on the KDD-cup 1999 data. Of the 46 examined variables, 16 were identified as robust risk factors, and the classification showed similar performances in sensitivity, specificity, and correctly classified rate in comparison with the KDD-cup 1999 winning results that were based on a rule-based decision tree algorithm with all variables. The study emphasizes that the bootstrap simulation and logistic regression modeling techniques offer a novel approach to understanding and identifying risk factors for better information protection on network security.
Designing a Resilient and High Performance Network
Authors: Ajeeli Abid A. , Al-Bastaki Yousif
Published: February 2011

This article describes the detailed configuration and LAN infrastructure design at the University of Bahrain (UOB). The article describes the configuration based on the new setup and migration requirements and indicates how the design satisfies those requirements. The article explains the detailed configuration of the design process of the distribution layer switches and shows how these switches can be configured in the final implementation. The article also discusses the modifications that occurred during the implementation/migration phase. The design of the network at UOB campuses incorporates resiliency into the network core in order to manage problems effectively. This will enable user access points to remain connected to the network even in the event of a failure. This incorporation aims to provide services and benefits to users without impediments.
Multiple Casting in a Wired LAN Using CDMA Technique
Authors: Shaji Britto K.S. , Sankaranarayanan P.E.
Published: February 2011

In this paper, we discuss the details of a Code Division Multiple Access (CDMA)-based multiplecasting system in a wired Local Area Network (LAN). This technique enables multiple users to transmit and receive data simultaneously among themselves using a single serial wire link at any given time, hence, called multiplecasting. This is unlike the method followed with the Ethernet in a wired LAN. With security being the prime demand of today’s world, allowing multiple users to access the channel simultaneously may be critical; but in this respect, the CDMA technology proposed by us, since it uses unique code for each user, also provides a solution to the problem. In this paper we aimed at simulating this technique. The simulation was done using Mat lab. We studied the effectiveness of the scheme, and the results are discussed in this paper.
Interaction Between MIMD-Poly and PIPD-Poly Algorithms and Other TCP Variants in Multiple Bottleneck TCP Networks
Authors: Chandrasekaran M. , Wahida Banu R.S.D.
Published: February 2011

This paper introduces and analyzes a class of non-linear congestion control algorithms called polynomial congestion control algorithms. They generalize the Additive Increase and Multiplicative Decrease (AIMD) algorithms used for Transmission Control Protocol (TCP) connections. These algorithms provide additive increase using a polynomial of the inverse of the current window size and provide multiplicative decrease using the polynomial of the current window size. There are infinite numbers of TCP-compatible polynomial algorithms by assuming a polynomial of a different order. This paper analyzes the interaction between the two models (Multiplicative Increase and Multiplicative Decrease/MIMD-Poly and Polynomial Increase and Polynomial Decrease/PIPD-Poly) of these generalized algorithms, for wired (with unicast and multicast) and wireless TCP networks. TCP compatibility of these algorithms is evaluated using the simulations of the implementations of the proposed two models. Simulations are done using ns2, a discrete event simulator. The model MIMD-Poly is proved to be TCP compatible. The results of the simulation are compared with TCP variants, such as TCP/Tahoe, TCP/Reno, TCP/New Reno and TCP/Vegas. The comparison shows that both algorithms perform better in terms of throughput.
Location Area Design Algorithms for Minimizing Signalling Costs in Mobile Networks
Authors: Simon Vilmos , Imre Sándor
Published: February 2011

In the next generation, IP-based mobile networks, one of the most important QoS parameters, are the delay and the delay variation. The cell handover causes incremental signalling traffic, which can be critical from the point of view of delay variation. It worsens the quality param-eters of the real-time services, which are the backbone of next generation mobile commercial services. We have designed and implemented two algorithms: a location area forming algo-rithm (LAFA) and a cell regrouping algorithm (CEREAL), which can help us to guarantee QoS parameters in the next generation mobile networks. We used our realistic mobile environment simulator to generate input statistics on cell changes and incoming calls for our algorithms and by comparing the values of the cost functions proposed by us, we recognized that significant reduction was achieved in the amount of the signalling traffic; the location update cost was decreased by 40-60% in average.
A Methodology for Performance, Content Analysis, and Configuration of Audio/Video-on-Demand Services
Authors: Paneda Xabiel G. , Melendi David , Garcia Roberto , Vilas Manuel , Garcia Victor
Published: February 2011

This article presents a methodology for performance analysis and configuration of audio/video- on-demand services. To maintain a good quality of service and to make a profit for the content provider, services must have the optimum configuration. With this aim, the configuration process must be based on an accurate service behavioural analysis which evaluates the quality and the quantity of resources, contents and subscribers. This analysis can be performed using monitored information and predictions of a near future behaviour using laboratory experiments. To formalize both analysis and configuration, a methodology must be developed in order to help service managers attain a good performance and at the same time, make a profit for their companies. All the methodology goals are based on the principle that ‘a satisfied client provides more profit‘. Moreover, the methodology is prepared to be extensible, and adaptable to new configuration possibilities, data, analyses or goals.
Peer-to-Peer IP Traffic Classification Using Decision Tree and IP Layer Attributes
Authors: Raahemi Bijan , Hayajneh Ahmad , Rabinovitch Peter
Published: February 2011

We present a new approach using data-mining technique and, in particular, decision tree to classify peer-to-peer (P2P) traffic in IP networks. We captured the Internet traffic at a main gateway router, performed preprocessing on the data, selected the most significant attributes, and prepared a training-data set to which the decision-tree algorithm was applied. We built several models using a combination of various attribute sets for different ratios of P2P to non-P2P traffic in the training data. We observed that the accuracy of the model increases significantly when we include the attributes “Src IP addr” and “Dst IP addr” in building the model. By detecting communities of peers, we achieved classification accuracy of higher than 98%. Consequently, we recommend that: (a) the classification must be done within the authority of the Internet service providers (ISP) in order to detect communities of peers, and (b) the decision tree needs to be frequently trained to ensure the fairness and correctness of the classification algorithm. Our approach is based only on information in the IP layer, eliminating the privacy issues associated with deep-packet inspection.
An Energy Aware Multi-Path Routing Algorithm for Mobile Ad Hoc Networks
Authors: Harous S. , Aldubai M. , Nasir Q.
Published: February 2011

Due to the new technology development, mobile ad hoc networks are becoming very important. The nodes that make up the mobile ad hoc network are battery powered. The problem of conserving energy at nodes is very important and a challenging one. In this article we present an Energy Aware Multi-path Dynamic Source Routing protocol (EAMPDSR). This protocol is based on the existing on-demand Dynamic Source Routing protocol (DSR). It is energy aware and uses a multi-path technique. EA-MPDSR reduces the energy consumed per received data bytes as well as prolongs the network lifetime, which leads to improvement in the performance of the network. The simulation results show the EA-MPDSR protocol performs better than conventional DSR and maximum of minimum energy DSR (MME-DSR) protocols.
Multivariate Fuzzy Analysis for Mobile Ad hoc Network Threat Detection
Authors: Alampalayam Sathish Kumar , Natsheh Essam F.
Published: February 2011

Detection of malicious, compromised and selfish node attacks is urgently needed to protect Mobile Ad hoc Networks (MANET) and their applications from failures. Once a MANET component is affected by a malicious, compromised or selfish node its operational state shifts from normal state to vulnerable state. Online monitoring mechanisms can collect important MANET network data that can be effectively used to detect abnormal behaviors caused by attacks. In this article we develop an online multivariate analysis algorithm to analyze the behavior of network resources and protocols to proactively detect MANET attacks. This algorithm is based on multivariate fuzzy analysis technique. We have validated the algorithm and demonstrated how it can effectively detect wellknown attacks such as Denial of Service in MANET.
Ontology-Based Network Planning
Authors: Umar Amjad , Subbaraman Ramesh
Published: February 2011

This article describes an approach to building and using a Network Ontology (NO) for network planning projects with particular focus on real-life enterprise networks. In addition to the ontology, we have developed a Network Markup Language (NML) based on the ontology that can be used to describe real life networks. We have also developed network patterns that capture the most common and best practices in network design and represented them in the proposed NML. Finally, we have developed a Web-based tool that uses the NO, NML and network patterns to quickly generate network plans for given situations. The practical contribution of this article is that it ties ontologies to the practice of network planning and network patterns, including decisions such as network device selection.
Dynamics and Future of the Information and Communication Technology Sector in Canada
Authors: Khan Shahzad , Raahemi Bijan
Published: February 2011

The Canadian Information and Communication Technology (ICT) accounted for $60.6 billion to Canadian Gross Domestic Product (GDP) by 2006. In this paper, we analyze the dynamics and the key factors involved in the downfall of the ICT sector during the period of 2000-2003. In particular, we discuss factors including low-cost capital, irrational forecasts, excessive investment in innovative solutions, excessive demand, lack of vision, lack of product differentially, and poor business models. The analysis depicts the current trend in telecom sector, and predicts what future holds for it. The study forecasts the rate of growth of the ICT telecommunication sector till 2015, draws a comparison of GDPs with and without telecom contributions, and demonstrates the impact of telecom sector on the ICT and Canadian economy. We also refer to disruptive technologies that may cause a significant impact on the economy in the near future.
Integrating Caching Techniques in CDNs using a Classification Approach
Authors: Pallis George , Stamos Konstantinos , Vakali Athena , Thomas Charilaos , Andreadis George
Published: February 2011

Content Delivery Networks (CDNs) provide an efficient support for serving “resource-hungry” applications while minimizing the network impact of content delivery as well as shifting the traffic away from overloaded origin servers. However, their performance gain is limited since the storage space in CDN’s servers is not used optimally. In order to manage their storage capacity in an efficient way, we integrate caching techniques in CDNs. The challenge is to decide which objects would be devoted to caching so as the CDN’s server may be used both as a replicator and as a proxy server. In this article, we propose a nonlinear, nonparametric model which classifies the CDN’s server cache into two parts. Through a detailed simulation environment, we show that the proposed technique can yield significant reduction in user-perceived latency as compared with other heuristic schemes.
A Cross-Layer Design Framework using Functional Components
Authors: Slavik Mike , Mahgoub Imad , Badi Ahmed , Sibai Fadi
Published: February 2011

We present a framework for cross-layer optimization in small, resource-constrained wireless communication systems that require a high degree of optimization. We argue that often these systems allow for a departure from conventional OSI network stack design principles, opening up broad opportunities for optimizations. We examine these new opportunities and propose a design strategy to take advantage of them. Simulation results are presented in support of our design framework proposal and as motivation for future work in this important area.
Slot Allocation Algorithms for Minimizing Delay in Alarm-Driven WSNs Applications
Authors: Macedo Mário , Grilo António , Nunes Mário
Published: February 2011

Energy-efficiency and latency requirements in alarm-driven Wireless Sensor Networks often demand the use of TDMA protocols with special features such as cascading of timeslots, in a way that the sensor-to-sink delay bound can stay below the duration of a single frame. However, this single TDMA frame should be as small as possible. The results presented in this paper, point to the conclusion that a largest-distances-first strategy can achieve the smallest single frame sizes, and also the lowest frame size variations. A quite simple distributed version of this algorithm is presented, which obtains the same results of its centralized version. Simulations also show that this discipline presents the best results in terms of sensor-to-sink slot distance, even if they require a few more slots than breadth-first in multi-frame scenarios.
A Distributed Secure Architecture for Vehicular Ad Hoc Networks
Authors: Gazdar Tahani , Belghith Abdelfettah , Benslimane Abderrahim
Published: February 2011

In this paper, the authors propose a dynamic Public Key Infrastructure (PKI) for vehicular ad hoc networks to distribute the role of the central certification authority (CA) among a set of dynamically elected CAs. The election process is based on a clustering algorithm relying on trust levels and relative mobility. Furthermore, the authors have adapted the Dynamic Demilitarized Zones to protect the elected CAs from malicious nodes and enable them to act as registration authorities (RA). Extensive simulations are conducted to evaluate the performance of the clustering algorithm and investigate the impact of the vehicle speed, the vehicle average arrival rate, and the percentage of confident vehicles on the stability and efficiency of the security infrastructure. The authors demonstrate the percentage of confident nodes has a little impact on these performance metrics and that the minimum number of CAs to cover the entire platoon.
A Test of the Law of Demand in a Virtual World
Authors: Castronova Edward , Bell Mark W. , Cornell Robert , Cummings James J. , Emigh Will , Falk Matthew , Fatten Michael , LaFourest Paul , Mishler Nathan
Published: February 2011

We report results of an experiment on prices and demand in a fantasy-based virtual world. A virtual world is a persistent, synthetic, online environment that can be accessed by many users at the same time. Because most virtual worlds are built around a fantasy theme, complete with magic, monsters, and treasure, there is considerable skepticism that human behavior in such environments is in any way “normal.” Our world, “Arden,” was designed to test whether players in a typical fantasy environment were economically “normal.” Specifically, we tested whether fantasy gamers conform to the law of demand, which states that increasing the price of a good, all else equal, will reduce the quantity demanded. We created two exactly equivalent worlds, and randomly assigned players to one or the other. The only difference in the two worlds was that the price of a single good, a health potion, was twice as high in the experimental world than in the control. We allowed players (N = 43) to enter and play the environment for a month.
Rules of Engagement
Authors: Gajadhar B. J. , de Kort Y. A.W. , IJsselsteijn W. A.
Published: February 2011

This article presents an empirical study of social setting as a determinant of player involvement in competitive play. We conceptualize player experience as comprising of components of involvement and enjoyment. Involvement relates to the attentional pull of games encompassing feelings of immersion, engagement and flow. Enjoyment taps into the fun and frustration of playing. A few recent studies indicate that co-players boost player enjoyment, yet the effect on involvement is still largely unknown. In line with enjoyment, involvement could increase with the sociality of settings. On the other hand, the presence of others provides a potential distracter and threat to involvement in games. Results of an experiment where social setting was manipulated within groups indicated that players’ involvement remains constant or even increases when mediated or co-located co-play is compared to solitary play. Hence, co-players do not break the spell of a game, but become part of the magic circle.
Evaluating User Experience of Actual and Imagined Movement in BCI Gaming
Authors: van de Laar Bram , Reuderink Boris , Bos Danny Plass-Oude , Heylen Dirk
Published: February 2011

Most research on Brain-Computer Interfaces (BCI) focuses on developing ways of expression for disabled people who are not able to communicate through other means. Recently it has been shown that BCI can also be used in games to give users a richer experience and new ways to interact with a computer or game console. This paper describes research conducted to find out what the differences are between using actual and imagined movement as modalities in a BCI game. Results show that there are significant differences in user experience and that actual movement is a more robust way of communicating through a BCI.
Local Inactivation of Sphingosine 1-Phosphate in Lymph Nodes Induces Lymphopenia
Authors: Sensken Sven-Christian , Nagarajan Manju , Bode Constantin , Gräler Markus H.
Published: February 2011

Sphingosine 1-phosphate (S1P) initiates T and B cell exit from lymphoid tissues by activating the S1P1 receptor on lymphocytes. To define the mechanistic details of this ligand–receptor interaction, the biological activity of the S1P-blocking Ab Sphingomab was investigated. Treatment of mice with Sphingomab resulted in blood B and T cell lymphopenia. Although Sphingomab blocked S1P1-mediated calcium flux and receptor downregulation by S1P in vitro, plasma from Sphingomab-treated mice demonstrated a 4-fold increase in S1P concentration and largely retained its stimulating activity on S1P receptors. Plasma-borne S1P was obviously not sufficiently inactivated by Sphingomab to account for the observed lymphopenia. Therefore, we addressed the local S1P-blocking activity of Sphingomab in spleen and peripheral lymph nodes (pLNs) as a potential cause of PBL depletion. Transwell chemotaxis assays revealed the migration of freshly isolated splenocytes, but not pLN cells to S1P. However, chemotaxis of pLN cells was regained after culture in S1P-low medium, and pLN cells isolated from Sphingomab-treated mice also revealed enhanced chemotaxis to S1P, indicating substantial local inactivation of S1P in pLN after Sphingomab treatment. We conclude that treatment with the S1P-blocking Ab Sphingomab induces lymphopenia by inactivating S1P locally in pLN and not systemically in plasma. Consequently, the presence of local S1P amounts in secondary lymphoid organs contributes to B and T cell egress.
La comunicación en las organizaciones del tercer sector
Authors: Durán Bravo Patricia , Fernández Fuentes María Belén
Published: February 2011

Las organizaciones del Tercer Sector favorecen el desarrollo social debido a  su capacidad de producir capital humano y capital social en una sociedad (Putman, 2001). Esto implica un cambio positivo en las relaciones de individuos, grupos e instituciones en una sociedad, con la finalidad de alcanzar el bienestar social. A nivel mundial las expectativas sobre la capacidad de respuesta a los problemas sociales y la transparencia de las OTS van en incremento. En México, esta problemática es más compleja, ya que es necesario enfrentar la escasa profesionalización, el bajo nivel de transparencia y rendición de cuentas y una débil cultura de la participación en la sociedad civil organizada (ITAM 2010). Ante esto, es necesario señalar que el desarrollo de la sociedad civil organizada dependerá en gran medida de su capacidad comunicar sus valores a la sociedad mexicana y lograr un cambio social y cultural. Por lo que, las OTS deben tomar iniciativas estratégicas que refuercen la confianza y la reputación; con donantes públicos y privados cada vez más exigentes en sus criterios para seleccionar proyectos y conceder recursos; con una sociedad poco participativa; y finalmente, con problemáticas sociales cada vez más complejas.
Randomized Controlled Clinical Trial to Access Efficacy and Safety of Miltefosine in the Treatment of Cutaneous Leishmaniasis Caused by Leishmania (Viannia) guyanensis in Manaus, Brazil
Authors: Chrusciak-Talhari Anette , Dietze Reynaldo , Chrusciak Talhari Carolina , da Silva Roberto Moreira , Gadelha Yamashita Ellen Priscila , de Oliveira Penna Gerson , Lima Machado Paulo Roberto , Talhari Sinésio
Published: February 2011

Miltefosine has been used in the treatment of several new world cutaneous leishmaniasis (CL) species with variable efficacy. Our study is the first evidence on its clinical efficacy in Leishmania (Viannia) guyanensis. In this phase II/III randomized clinical trial, 90 CL patients were randomly allocated (2:1) to oral miltefosine (2.5 mg/kg/day/28 days) (N = 60) or parenteral antimony (15–20 mg/Sb/kg/day/20 days) (N = 30) according to age groups: 2–12 y/o and 13–65 y/o. Patients were human immunodeficiency virus (HIV) noninfected parasitological proven CL without previous treatment. Definitive cure was accessed at 6 months follow-up visit. No severe adverse events occurred. Vomiting was the most frequent adverse event (48.3%) followed by nausea (8.6%) and diarrhea (6.7%). Cure rates were 71.4% (95% confidence interval [CI] = 57.8–82.7) and 53.6% (95% CI = 33.9–72.5) (P = 0.05) for miltefosine and antimonial, respectively. There were no differences in cure rates between age groups within the same treatment arms. Miltefosine was safe and relatively well tolerated and cure rate was higher than antimony.
A Focus of Dogs and Rickettsia massiliae–Infected Rhipicephalus sanguineus in California
Authors: Beeler Emily , Abramowicz Kyle F. , Zambrano Maria L. , Sturgeon Michele M. , Khalaf Nada , Hu Renjie , Dasch Gregory A. , Eremeeva Marina E.
Published: February 2011

A recurrent focus of Rhipicephalus sanguineus infestation was investigated in a suburban area of southern California after reports of suspected Rocky Mountain spotted fever in two dogs on the same property. Abundant quantities of Rh. sanguineus were collected on the property and repeatedly from each dog, and Rickettsia massiliae DNA was detected by polymerase chain reaction (PCR). Whole blood and serum samples from four dogs were tested by using PCR and microimmunofluorescent assay for antibodies against spotted fever group rickettsiae. Serum samples from all four dogs contained antibodies reactive with R. massiliae, R. rhipicephali, R. rickettsii, and 364D Rickettsia but no rickettsial DNA was detected by PCR of blood samples. Serum cross-absorption and Western blot assays implicated R. massiliae as the most likely spotted fever group rickettsiae responsible for seropositivity. To our knowledge, this is the first detection of R. massiliae in ticks in California.
Genetic Diversity of Polymorphic Vaccine Candidate Antigens (Apical Membrane Antigen-1, Merozoite Surface Protein-3, and Erythrocyte Binding Antigen-175) in Plasmodium falciparum Isolates from Western and Central Africa
Authors: Soulama Issiaka , Bigoga Jude D. , Ndiaye Magatte , Bougouma Edith C. , Quagraine Josephine , Casimiro Prisca N. , Stedman Timothy T. , Sirima Sodiomon B.
Published: February 2011

The malaria vaccine candidate antigens erythrocyte binding antigen 175 (EBA-175), merozoite surface protein 3 (MSP-3), and apical membrane antigen (AMA-1) from Plasmodium falciparum isolates from countries in central and west Africa were assessed for allelic diversity. Samples were collected on filter paper from 600 P. falciparum-infected symptomatic patients in Cameroon, Republic of Congo, Burkina Faso, Ghana, and Senegal and screened for class-specific amplification fragments. Genetic diversity, assessed by mean heterozygosity, was comparable among countries. We detected a clinical increase in eba 175 F-allele frequency from west to east across the study region. No statistical difference in msp-3 allele distribution between countries was observed. The ama-1 3D7 alleles were present at a lower frequency in central Africa than in West Africa. We also detected little to no genetic differentiation among sampling locations. This finding indicates that, at least at the level of resolution offered by restriction fragment length polymorphism analysis, these antigens showed remarkable genetic homogeneity throughout the region sampled, perhaps caused by balancing selection to maintain a diverse array of antigen haplotyes.
Modeling the Relationship between Precipitation and Malaria Incidence in Children from a Holoendemic Area in Ghana
Authors: Krefis Anne Caroline , Schwarz Norbert Georg , Krüger Andreas , Fobil Julius , Nkrumah Bernard , Acquah Samuel , Loag Wibke , Sarpong Nimako , Adu-Sarkodie Yaw , Ranft Ulrich , May Jürgen
Published: February 2011

Climatic factors influence the incidence of vector-borne diseases such as malaria. They modify the abundance of mosquito populations, the length of the extrinsic parasite cycle in the mosquito, the malarial dynamics, and the emergence of epidemics in areas of low endemicity. The objective of this study was to investigate temporal associations between weekly malaria incidence in 1,993 children < 15 years of age and weekly rainfall. A time series analysis was conducted by using cross-correlation function and autoregressive modeling. The regression model showed that the level of rainfall predicted the malaria incidence after a time lag of 9 weeks (mean = 60 days) and after a time lag between one and two weeks. The analyses provide evidence that high-resolution precipitation data can directly predict malaria incidence in a highly endemic area. Such models might enable the development of early warning systems and support intervention measures.
Comparison of Microscopy, Culture, and Conventional Polymerase Chain Reaction for Detection of Blastocystis sp. in Clinical Stool Samples
Authors: Roberts Tamalee , Barratt Joel , Harkness John , Ellis John , Stark Damien
Published: February 2011

We tested 513 stool samples from patients in Sydney, Australia for Blastocystis by using five diagnostic techniques: microscopy of a permanently stained smear using a modified iron-hematoxylin stain, two xenic culture systems (a modified Boeck and Drbohlav's medium and tryptone, yeast extract, glucose, methionine-9 medium), and two published conventional polymerase chain reaction methods specific for the small subunit ribosomal DNA. Ninety-eight (19%) samples were positive for Blastocystis in one or more of the diagnostic techniques. The PCR 2 method was the most sensitive at detecting Blastocystis with a sensitivity of 94%, and the least sensitive was microscopy of the permanent stain (48%). Subtype 3 was the most predominant subtype (present in 43% of samples assigned to this group). This study highlights the low sensitivity of microscopy when used as the sole diagnostic modality for detection of Blastocystis sp.
Fetal Face
Authors: Singh Kuldeep
Published: January 2011

This article discusses normal facial anatomy and the facial abnormalities, which can be diagnosed by 2D and 3D ultrasound. As the neonatal face is so visible one has to do a careful survey of the fetal face with all possible modalities to enhance the sonographer's expertise. Facial anomalies can be the tip of an iceberg with the diagnosis prompting evaluation for chromosomal abnormalities.
Ultrasonographic Evaluation of the Fetal Neural Axis
Authors: Tomar Sakshi
Published: January 2011

The central nervous system is probably the first organ system to be investigated in utero by diagnostic ultrasound. Anencephaly was the first congenital anomaly to be recognized by this technique before viability. Since then, the investigation of the fetal neural axis has steadily remained a central issue of antenatal sonography. Such an interest is explained by a number of reasons. CNS anomalies are frequent and often have a severe prognosis. In many cases they have a genetic background: consequently a large number of couples are at risk and warrant antenatal diagnosis. Modern high resolution ultrasound equipment yields a unique potential in evaluating normal and abnormal anatomy of the fetal neural axis beginning at very early stages of development.
Role of Color Doppler in the Diagnosis of Extracardiac Fetal Abnormalities
Authors: Praveen TLN , Surekha P
Published: January 2011

Color Doppler is useful in evaluating fetal cardiac abnormalities and in assessing fetal hemodynamics in a hypoxic fetus. Color Doppler is extremely useful in evaluating extracardiac fetal abnormalities.
The Use of Ultrasound in Natural Disasters
Authors: Loaiza Jose Leonardo
Published: January 2011

During the tragedy in Haiti, I accidentally had the opportunity to perform a couple of ultrasounds that really made a difference for the patients I saw. In the next article I will share my unforgettable story that made me aware of the sum importance to learn about the use of these devices in those scenarios. I hope that my story will help the experts in ultrasound and the companies that build them, to develop guidelines and workshops to get knowledge in this wonderful piece of technology that I believe should be called the stethoscope of the future.
The Potential of Transvaginal Three-dimensional Color/Power Doppler Ultrasound in Detection of Colorectal Cancer
Authors: Honemeyer Ulrich , Mathias Jawahar , Aduh Prosper
Published: January 2011

Colorectal cancer (CRC) is the fourth most common cancer in men and the third most common cancer in women worldwide. The recent decline of CRC in the USA has been attributed to successful development of screening programs. In the last 20 years, endorectal ultrasound (ERUS) has become the primary method for locoregional staging of rectal cancer. Transvaginal sonography (TVS), with a high-frequency probe, obtains excellent image resolution of deep pelvic organs. TVS not only enables diagnosis and treatment in gynecology, infertility, and early pregnancy but also has the potential to detect other structural abnormalities within its reach, such as neoplasm of the rectosigmoid. Three-dimensional power Doppler ultrasound (3D PD) can depict the morphology of the vessel tree of tumors, and thus help to discriminate between benign and malignant neoplasm. In this case of a 42-year-old patient, an adnexal mass was diagnosed by TVS. Three-dimensional ultrasound gave topographic evidence of sigmoid colon tumor. Spectral Doppler and 3D PD diagnostic criteria of tumor vasculature, demonstrated in this neoplasm, were highly suspicious of malignancy. TVS diagnosis initiated endoscopic histological verification of adenocarcinoma of the sigma and timely surgical intervention.
Modeling secondary organic aerosol formation from isoprene oxidation under dry and humid conditions
Authors: Couvidat F. , Seigneur C.
Published: January 2011

Abstract. A new model for the formation of secondary organic aerosol (SOA) from isoprene was developed. This model uses surrogate molecular species (hydroxy-hydroperoxides, tetrols, methylglyceric acid, organic nitrates) to represent SOA formation. The development of this model used available experimental data on yields and molecular composition of SOA from isoprene and methacrolein oxidation. This model reproduces the amount of particles measured in smog chambers under both low-NOx and high-NOx conditions. Under low-NOx conditions, the model reproduces the transitional formation of hydroxy-hydroperoxides particles, which are photolyzed and lead to SOA mass decrease after reaching a maximum. Under high-NOx conditions, particles are assumed to be formed mostly from the photo-oxidation of a PAN-type molecule derived from methacrolein (MPAN). This model successfully reproduces the complex NOx-dependence of isoprene oxidation and suggests a possible yield increase under some high-NOx conditions. Experimental data correspond to dry conditions (RH < 10%). However, particles formed from isoprene are expected to be highly hydrophilic, and isoprene oxidation products would likely partition between an aqueous phase and the gas phase at high humidity in the atmosphere. The model was extended to take into account the hydrophilic properties of SOA, which are relevant under atmospheric conditions, and investigate the effect of particulate liquid water on SOA formation. An important increase in SOA mass was estimated for humid conditions due to the hydrophilic properties. Experiments under high relative humidity conditions should be conducted to confirm the results of this study, which have implications for SOA modeling.
Quasi-geostrophic turbulence and generalized scale invariance, a theoretical reply
Authors: Schertzer D. , Tchiguirinskaia I. , Lovejoy S. , Tuck A.
Published: January 2011

Abstract. Lindborg et al. (2010) claim that the spectrum power law E(k) ≈ k−3 on scales ≥600 km obtained with the help of commercial jetliner trajectory deviations (GASP and Mozaic databases) could not be brought into question (Lovejoy et al., 2009a), because this spectrum corresponds to "a well known theory of quasi-geostrophic turbulence developed by Charney (1971)". Lindborg et al. (2010) also claim that "limitations [of this theory] have been relaxed in many of the modern models of atmospheric turbulence". We show that both claims are irrelevant and that generalized scale invariance (GSI) is indispensable to go beyond the quasi-geostrophic limitations, to go in fact from scale analysis to scaling analysis. This enables us to derive vorticity equations in a space of (fractional) dimension D=2+Hz (0 ≤ Hz ≤1), which seem to be an interesting dynamical alternative to the quasi-geostrophic approximation and turbulence.
Ultraviolet actinic flux in clear and cloudy atmospheres: model calculations and aircraft-based measurements
Authors: Palancar G. G. , Shetter R. E. , Hall S. R. , Toselli B. M. , Madronich S.
Published: January 2011

Abstract. Ultraviolet (UV) actinic fluxes measured with two Scanning Actinic Flux Spectroradiometers (SAFS) aboard the NASA DC-8 aircraft are compared with the Tropospheric Ultraviolet-Visible (TUV) model. The observations from 17 days in July–August 2004 (INTEX-NA field campaign) span a wide range of latitudes (27.5° N–53.0° N), longitudes (45.1° W–139.5° W), altitudes (0.1–11.9 km), ozone columns (285.4–352.7 DU), and solar zenith angles (1.7°–85°). Both cloudy and cloud-free conditions were encountered. For cloud-free conditions, the ratio of observed to clear-sky-model actinic flux (integrated from 298 to 422 nm) is 1.01±0.04, i.e. in good agreement with observations. The agreement improves to 1.00±0.03 for the down-welling component under clear sky conditions. In the presence of clouds, both down-welling and up-welling components show reductions or enhancements from clear sky values, depending on the position of the airplane relative to clouds. The correlations between up-welling and down-welling deviations are well reproduced with sensitivity studies using the TUV model, and are understood qualitatively with a simple conceptual model. This analysis of actinic flux observations illustrates opportunities for future evaluations of photolysis rates in three-dimensional chemistry-transport models.
Condensational uptake of semivolatile organic compounds in gasoline engine exhaust onto pre-existing inorganic particles
Authors: Li S.-M. , Liggio J. , Graham L. , Lu G. , Brook J. , Stroud C. , Zhang J. , Makar P. , Moran M. D.
Published: January 2011

Abstract. This paper presents the results of laboratory studies on the condensational uptake of gaseous organic compounds in the exhaust of a light-duty gasoline engine onto preexisting sulfate and nitrate seed particles. Significant condensation of the gaseous organic compounds in the exhaust occurs onto pre-existing inorganic particles on a time scale of 2–5 min. The amount of condensed organic mass (COM) is proportional to the seed particle mass, suggesting that the uptake is due to dissolution, not adsorption. The solubility decreases as a power function with increased dilution of the exhaust, ranging from 0.23 g/g at a dilution ratio of 81, to 0.025 g/g at a dilution ratio of 2230. The solubility increases nonlinearly with increasing concentration of the total hydrocarbons in the gas phase (THC), rising from 0.12 g/g to 0.26 g/g for a CTHC increase of 1 to 18 μg m−3, suggesting that more organics are partitioned into the particles at higher gas phase concentrations. In terms of gas-particle partitioning, the condensational uptake of THC gases in gasoline engine exhaust can account for up to 30% of the total gas+particle THC. By incorporating the present findings, regional air quality modelling results suggest that the condensational uptake of THC onto sulfate particles alone can be comparable to the primary particle mass under moderately polluted ambient conditions. These findings are important for modelling and regulating the air quality impacts of gasoline vehicular emissions.
Hydrologic response of a semi-arid watershed to spatial and temporal characteristics of convective rain cells
Authors: Yakir H. , Morin E.
Published: January 2011

Abstract. Rain can be measured and represented in many ways such as point data from rain gauges, grid data from meteorological radar, or interpolated data. In this paper we represent rain fields by implementing a rain cell model of convective rain cells. The rain fields are used as an input to a hydrological model to test the watershed response to spatial and temporal characteristics of the rain cells. As a case study we tested an extreme storm event over a semi-arid watershed in southern Israel. The rain cell model was found to simulate the rain storm adequately. The use of these modeled cells allowed us to test the sensitivity of the watershed hydrological response to rain cell characteristics and it was found that the watershed is mainly sensitive to the starting location of the rain cell. Relatively small changes in the rain cell's location, speed and direction may increase watershed peak discharge by three-fold.
Measurement of absolute gravity acceleration in Firenze
Authors: de Angelis M. , Greco F. , Pistorio A. , Poli N. , Prevedelli M. , Saccorotti G. , Sorrentino F. , Tino G. M.
Published: January 2011

Abstract. This paper reports the results from the accurate measurement of the acceleration of gravity g taken at two separate premises in the Polo Scientifico of the University of Firenze (Italy). In these laboratories, two separate experiments aiming at measuring the Newtonian constant and testing the Newtonian law at short distances are in progress. Both experiments require an independent knowledge on the local value of g. The only available datum, pertaining to the italian zero-order gravity network, was taken more than 20 years ago at a distance of more than 60 km from the study site. Gravity measurements were conducted using an FG5 absolute gravimeter, and accompanied by seismic recordings for evaluating the noise condition at the site. The absolute accelerations of gravity at the two laboratories are (980 492 160.6 ± 4.0) μGal and (980 492 048.3 ± 3.0) μGal for the European Laboratory for Non-Linear Spectroscopy (LENS) and Dipartimento di Fisica e Astronomia, respectively. Other than for the two referenced experiments, the data here presented will serve as a benchmark for any future study requiring an accurate knowledge of the absolute value of the acceleration of gravity in the study region.
Ice genesis and its long-term mass balance and dynamics in Scărişoara Ice Cave, Romania
Authors: Perşoiu A. , Pazdur A.
Published: January 2011

Abstract. The paleoclimatic significance of the perennial ice deposit in Scărişoara Ice Cave has been remarked on since the early 20th century, but a lack of understanding of the processes involved in the genesis, age and long-term dynamics and volume fluctuations of ice hampered all attempts to extract valuable data on past climate and vegetation changes. In this paper, we present a model of ice genesis and dynamics, based on stable isotopes, ice level monitoring (modern and archived) and radiocarbon dating of organic matter found in the ice. Ice in this cave mostly consists of layers of lake ice, produced as liquid water freezes from top to bottom in mid-autumn, and floor ice, produced as inflow water in winter freezes on top of the lake ice. This mechanism was also acting in the past, during the Medieval Warm Period and the Little Ice Age. The ice block is not stable in shape and volume, being continuously modified by ablation on top and sides, basal melting and lateral flow. Radiocarbon dating shows that the ice block is older than 1000 years, but ice flow and differential basal melting suggesting that the ice could be much older.
Free Flow or Morality Bought: On the Construction of Remittances as an Object of Study
Authors: Eggebø Olav
Published: February 2011

This article describes how remittances have been represented in social scientific texts. Social scientists have predominantly linked discussions about remittances to discussions about development, and many observations regarding remittances have been put into theoretical models where their main purpose has been to verify those models of thought. Remittances have been presented as significant because of the instrumental effects they have for the economy, the society and/or the political system. In this way, discourses on remittances can illuminate not only views on remittances, they can also illuminate intrinsic views of how the world should look like. Remittances have merely been considered in the light of macro models and systems theory, detached from the persons that are in fact the senders and receivers of this money. In this article it is argued that these remittances should not be considered in an instrumental way. The "flow" of remittances is significantly regulated and sanctioned by moral representations linked to structures like household, family and gender. The transactions are manifestations of the personal relations between the actors of the transaction, and cannot be reduced into a model that treats the actors as isolated individuals.