bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling the internet is fun!
Authors: Towsley Don
Published: August 2008

This talk overviews some of the highlights and success stories in the mathematical modeling and analysis of the Internet (and other networks). We will begin with Kleinrock's seminal work on modeling store and forward networks and its extensions, and end with the successful development of fluid models for the current Internet. The rest of the talk will focus on lessons learned from these endeavors and how modeling and analysis can and will play a role in the development of new networks (e.g., wireless networks, application-level networks). Finally, we conclude that one can have fun modeling networks while at the same time make a living.
Floodless in seattle
Authors: Kim Changhoon , Caesar Matthew , Rexford Jennifer
Published: August 2008

IP networks today require massive effort to configure and manage. Ethernet is vastly simpler to manage, but does not scale beyond small local area networks. This paper describes an alternative network architecture called SEATTLE that achieves the best of both worlds: The scalability of IP combined with the simplicity of Ethernet. SEATTLE provides plug-and-play functionality via flat addressing, while ensuring scalability and efficiency through shortest-path routing and hash-based resolution of host information. In contrast to previous work on identity-based routing, SEATTLE ensures path predictability and stability, and simplifies network management. We performed a simulation study driven by real-world traffic traces and network topologies, and used Emulab to evaluate a prototype of our design based on the Click and XORP open-source routing platforms. Our experiments show that SEATTLE efficiently handles network failures and host mobility, while reducing control overhead and state requirements by roughly two orders of magnitude compared with Ethernet bridging.
Shedding light on the glue logic of the internet routing architecture
Authors: Le Franck , Xie Geoffrey G. , Pei Dan , Wang Jia , Zhang Hui
Published: August 2008

Recent studies reveal that the routing structures of operational networks are much more complex than a simple BGP/IGP hierarchy, highlighted by the presence of many distinct instances of routing protocols. However, the glue (how routing protocol instances interact and exchange routes among themselves) is still little understood or studied. For example, although Route Redistribution (RR), the implementation of the glue in router software, has been used in the Internet for more than a decade, it was only recently shown that RR is extremely vulnerable to anomalies similar to the permanent route oscillations in BGP. This paper takes an important step toward understanding how RR is used and how fundamental the role RR plays in practice. We developed a complete model and associated tools for characterizing interconnections between routing instances based on analysis of router configuration data. We analyzed and characterized the RR usage in more than 1600 operational networks. The findings are: (i) RR is indeed widely used; (ii) operators use RR to achieve important design objectives not realizable with existing routing protocols alone; (iii) RR configurations can be very diverse and complex. These empirical discoveries not only confirm that the RR glue constitutes a critical component of the current Internet routing architecture, but also emphasize the urgent need for more research to improve its safety and flexibility to support important design objectives.
Bittorrent is an auction
Authors: Levin Dave , LaCurts Katrina , Spring Neil , Bhattacharjee Bobby
Published: August 2008

Incentives play a crucial role in BitTorrent, motivating users to upload to others to achieve fast download times for all peers. Though long believed to be robust to strategic manipulation, recent work has empirically shown that BitTorrent does not provide its users incentive to follow the protocol. We propose an auction-based model to study and improve upon BitTorrent's incentives. The insight behind our model is that BitTorrent uses, not tit-for-tat as widely believed, but an auction to decide which peers to serve. Our model not only captures known, performance-improving strategies, it shapes our thinking toward new, effective strategies. For example, our analysis demonstrates, counter-intuitively, that BitTorrent peers have incentive to intelligently under-report what pieces of the file they have to their neighbors. We implement and evaluate a modification to BitTorrent in which peers reward one another with proportional shares of bandwidth. Within our game-theoretic model, we prove that a proportional-share client is strategy-proof. With experiments on PlanetLab, a local cluster, and live downloads, we show that a proportional-share unchoker yields faster downloads against BitTorrent and BitTyrant clients, and that under-reporting pieces yields prolonged neighbor interest.
Network discovery from passive measurements
Authors: Eriksson Brian , Barford Paul , Nowak Robert
Published: August 2008

Understanding the Internet's structure through empirical measurements is important in the development of new topology generators, new protocols, traffic engineering, and troubleshooting, among other things. While prior studies of Internet topology have been based on active (traceroute-like) measurements, passive measurements of packet traffic offer the possibility of a greatly expanded perspective of Internet structure with much lower impact and management overhead. In this paper we describe a methodology for inferring network structure from passive measurements of IP packet traffic. We describe algorithms that enable 1) traffic sources that share network paths to be clustered accurately without relying on IP address or autonomous system information, 2) topological structure to be inferred accurately with only a small number of active measurements, 3) missing information to be recovered, which is a serious challenge in the use of passive packet measurements. We demonstrate our techniques using a series of simulated topologies and empirical data sets. Our experiments show that the clusters established by our method closely correspond to sources that actually share paths. We also show the trade-offs between selectively applied active probes and the accuracy of the inferred topology between sources. Finally, we characterize the degree to which missing information can be recovered from passive measurements, which further enhances the accuracy of the inferred topologies.
Donnybrook
Authors: Bharambe Ashwin , Douceur John R. , Lorch Jacob R. , Moscibroda Thomas , Pang Jeffrey , Seshan Srinivasan , Zhuang Xinyu
Published: August 2008

Without well-provisioned dedicated servers, modern fast-paced action games limit the number of players who can interact simultaneously to 16-32. This is because interacting players must frequently exchange state updates, and high player counts would exceed the bandwidth available to participating machines. In this paper, we describe Donnybrook, a system that enables epic-scale battles without dedicated server resources, even in a fast-paced game with tight latency bounds. It achieves this scalability through two novel components. First, it reduces bandwidth demand by estimating what players are paying attention to, thereby enabling it to reduce the frequency of sending less important state updates. Second, it overcomes resource and interest heterogeneity by disseminating updates via a multicast system designed for the special requirements of games: that they have multiple sources, are latency-sensitive, and have frequent group membership changes. We present user study results using a prototype implementation based on Quake III that show our approach provides a desirable user experience. We also present simulation results that demonstrate Donnybrook's efficacy in enabling battles of up to 900 players.
Solution of Singular and Nonsingular Initial and Boundary Value Problems by Modified Variational Iteration Method
Authors: Noor Muhammad Aslam , Mohyud-Din Syed Tauseef
Published: August 2008

We apply the modified variational iteration method (MVIM) for solving the singular and nonsingular initial and boundary value problems in this paper. The proposed modification is made by introducing Adomian′s polynomials in the correct functional. The suggested algorithm is quite efficient and is practically well suited for use in such problems. The proposed iterative scheme finds the solution without any discretization, linearization, perturbation, or restrictive assumptions. Several examples are given to verify the efficiency and reliability of the suggested algorithm.
Technique of Intravesical Laparoscopy for Ureteric Reimplantation to Treat VUR
Authors: Thakre Atul A. , Yeung C. K.
Published: August 2008

The prevalence of vesicoureteral reflux (VUR) has been estimated as 0.4 to 1.8% among the pediatric population. In children with urinary tract infection, the prevalence is typically from 30–50% with higher incidence occurring in infancy. When correction of VUR is determined to be necessary, traditionally open ureteral reimplantation by a variety of techniques has been the mainstay of treatment. This approach is justified because surgical correction affords a very high success rate of 99% in experienced hands and a low complication rate. In that context the purpose of presenting oursurgical technique: laparoscopic intravesical ureteric reimplantationis to highlight the use of laparoscopy to perform ureteric reimplantation for the management of pediatric VUR.
Synthesis and Optimization of MWCNTs on Co-Ni/MgO by Thermal CVD
Authors: Ryu H. , Singh B. K. , Bartwal K. S.
Published: August 2008

Multiwalled carbon nanotubes (MWCNTs) were prepared by the thermal chemical vapor deposition (CVD) technique. Monometallic and bimetallic Co and Ni combinations were used as a catalyst on MgO support. The mixer ofH2/C2H2was used as a carbon source. The prepared CNTs were found to possess different shapes, morphologies, and sizes. Maximum yield was found for 50% Co (MgO: 50% and Ni: 0%) catalyst at 600°C. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) techniques were used for structural analysis. Raman spectra were taken to investigate the quality and crystalline perfection of the prepared CNTs. The ratio of D- and G-bands (ID/IG) was measured from these spectra.
Peroxisome Proliferator–Activated Receptor-δ Agonist Enhances Vasculogenesis by Regulating Endothelial Progenitor Cells Through Genomic and Nongenomic Activations of the Phosphatidylinositol 3-Kinase/Akt Pathway
Authors: Han Jung-Kyu , Lee Hyun-Sook , Yang Han-Mo , Hur Jin , Jun Soo-In , Kim Ju-Young , Cho Chung-Hyun , Koh Gou-Young , Peters Jeffrey M. , Park Kyung-Woo , Cho Hyun-Jai , Lee Hae-Young , Kang Hyun-Jae , Oh Byung-Hee , Park Young-Bae , Kim Hyo-Soo
Published: August 2008

Background—

Despite the therapeutic potential of endothelial progenitor cells (EPCs) in ischemic vascular diseases, their insufficient numbers limit clinical applications. Peroxisome proliferator–activated receptor (PPAR)-δ belongs to the nuclear hormone receptor superfamily, and its functions in various tissues and cells are almost unexplored, especially with respect to vascular biology.

Methods and Results—

PPAR-δ activation in EPCs phosphorylated Akt, and this phosphorylation was mediated not only by genomic but also by nongenomic pathways through interaction with the regulatory subunit of phosphatidylinositol 3-kinase. PPAR-δ activation with agonist (GW501516 or L-165041) increased the proliferation of human EPCs and protected them from hypoxia-induced apoptosis. In addition, PPAR-δ activation enhanced EPC functions, such as transendothelial migration, and tube formation. These actions by PPAR-δ activation in EPCs were dependent on the phosphatidylinositol 3-kinase/Akt pathway. In ischemic hindlimb of mice models, transplantation of PPAR-δ agonist–treated human or mouse EPCs enhanced blood flow recovery to ischemic limbs compared with vehicle-treated EPCs. In EPCs from PPAR-δ–knockout mice, however, treatment with PPAR-δ agonist did not enhance in vivo vasculogenic potential. Systemic administration of PPAR-δ agonist increased hematopoietic stem cells in bone marrow and EPCs in peripheral blood, leading to improved vasculogenesis with incorporation of bone marrow–derived cells to new vessels in a corneal neovascularization model and limb salvage with better blood flow in an ischemic hindlimb model.

Conclusions—

The results of our study suggest that PPAR-δ agonist has therapeutic vasculogenic potential for the treatment of ischemic cardiovascular diseases.
The Spontaneous Imbalance of an Atmospheric Vortex at High Rossby Number
Authors: Schecter David A.
Published: August 2008

This paper discusses recent progress toward understanding the instability of a monotonic vortex at high Rossby number, due to the radiation of spiral inertia–gravity (IG) waves. The outward-propagating IG waves are excited by inner undulations of potential vorticity that consist of one or more vortex Rossby waves. An individual vortex Rossby wave and its IG wave emission have angular pseudomomenta of opposite sign, positive and negative, respectively. The Rossby wave therefore grows in response to producing radiation. Such growth is potentially suppressed by the resonant absorption of angular pseudomomentum in a critical layer, where the angular phase velocity of the Rossby wave matches the angular velocity of the mean flow. Suppression requires a sufficiently steep radial gradient of potential vorticity in the critical layer. Both linear and nonlinear steepness requirements are reviewed.

The formal theory of radiation-driven instability, or “spontaneous imbalance,” is generalized in isentropic coordinates to baroclinic vortices that possess active critical layers. Furthermore, the rate of angular momentum loss by IG wave radiation is reexamined in the hurricane parameter regime. Numerical results suggest that the negative radiation torque on a hurricane has a smaller impact than surface drag, despite recent estimates of its large magnitude.
Sensitivity Studies of the Role of Aerosols in Warm-Phase Orographic Precipitation in Different Dynamical Flow Regimes
Authors: Muhlbauer Andreas , Lohmann Ulrike
Published: August 2008

Aerosols serve as a source of cloud condensation nuclei (CCN) and influence the microphysical properties of clouds. In the case of orographic clouds, it is suspected that aerosol–cloud interactions reduce the amount of precipitation on the upslope side of the mountain and enhance the precipitation on the downslope side when the number of aerosols is increased. The net effect may lead to a shift of the precipitation distribution toward the leeward side of mountain ranges, which affects the hydrological cycle on the local scale.

In this study aerosol–cloud interactions in warm-phase clouds and the possible impact on the orographic precipitation distribution are investigated. Herein, simulations of moist orographic flow over topography are conducted and the influence of anthropogenic aerosols on the orographic precipitation formation is analyzed. The degree of aerosol pollution is prescribed by different aerosol spectra that are representative for central Switzerland. The simulations are performed with the Consortium for Small-Scale Modeling’s mesoscale nonhydrostatic limited-area weather prediction model (COSMO) with a horizontal grid spacing of 2 km and a fully coupled aerosol–cloud parameterization.

It is found that an increase in the aerosol load leads to a downstream shift of the orographic precipitation distribution and to an increase in the spillover factor. A reduction of warm-phase orographic precipitation is observed at the upslope side of the mountain. The downslope precipitation enhancement depends critically on the width of the mountain and on the flow dynamics. In the case of orographic precipitation induced by stably stratified unblocked flow, the loss in upslope precipitation is not compensated by leeward precipitation enhancement. In contrast, flow blocking may lead to leeward precipitation enhancement and eventually to a compensation of the upslope precipitation loss. The simulations also indicate that latent heat effects induced by aerosol–cloud–precipitation interactions may considerably affect the orographic flow dynamics and consequently feed back on the orographic precipitation development.
Wave-Driven Wind Jets in the Marine Atmospheric Boundary Layer
Authors: Hanley Kirsty E. , Belcher Stephen E.
Published: August 2008

The interaction between ocean surface waves and the overlying wind leads to a transfer of momentum across the air–sea interface. Atmospheric and oceanic models typically allow for momentum transfer to be directed only downward, from the atmosphere to the ocean. Recent observations have suggested that momentum can also be transferred upward when long wavelength waves, characteristic of remotely generated swell, propagate faster than the wind speed. The effect of upward momentum transfer on the marine atmospheric boundary layer is investigated here using idealized models that solve the momentum budget above the ocean surface. A variant of the classical Ekman model that accounts for the wave-induced stress demonstrates that, although the momentum flux due to the waves penetrates only a small fraction of the depth of the boundary layer, the wind profile is profoundly changed through its whole depth. When the upward momentum transfer from surface waves sufficiently exceeds the downward turbulent momentum flux, then the near-surface wind accelerates, resulting in a low-level wave-driven wind jet. This increases the Coriolis force in the boundary layer, and so the wind turns in the opposite direction to the classical Ekman layer. Calculations of the wave-induced stress due to a wave spectrum representative of fast-moving swell demonstrate upward momentum transfer that is dominated by contributions from waves in the vicinity of the peak in the swell spectrum. This is in contrast to wind-driven waves whose wave-induced stress is dominated by very short wavelength waves. Hence the role of swell can be characterized by the inverse wave age based on the wave phase speed corresponding to the peak in the spectrum. For a spectrum of waves, the total momentum flux is found to reverse sign and become upward, from waves to wind, when the inverse wave age drops below the range 0.15–0.2, which agrees reasonably well with previously published oceanic observations.
Mountain Waves Entering the Stratosphere
Authors: Smith Ronald B. , Woods Bryan K. , Jensen Jorgen , Cooper William A. , Doyle James D. , Jiang Qingfang , Grubišić Vanda
Published: August 2008

Using the National Science Foundation (NSF)–NCAR Gulfstream V and the NSF–Wyoming King Air research aircraft during the Terrain-Induced Rotor Experiment (T-REX) in March–April 2006, six cases of Sierra Nevada mountain waves were surveyed with 126 cross-mountain legs. The goal was to identify the influence of the tropopause on waves entering the stratosphere. During each flight leg, part of the variation in observed parameters was due to parameter layering, heaving up and down in the waves. Diagnosis of the combined wave-layering signal was aided with innovative use of new GPS altitude measurements. The ozone and water vapor layering correlated with layered Bernoulli function and cross-flow speed.

GPS-corrected static pressure was used to compute the vertical energy flux, confirming, for the first time, the Eliassen–Palm relation between momentum and energy flux (EF = −U · MF). Kinetic (KE) and potential (PE) wave energy densities were also computed. The equipartition ratio (EQR = PE/KE) changed abruptly across the tropopause, indicating partial wave reflection. In one case (16 April 2006) systematically reversed momentum and energy fluxes were found in the stratosphere above 12 km. On a “wave property diagram,” three families of waves were identified: up- and downgoing long waves (30 km) and shorter (14 km) trapped waves. For the latter two types, an explanation is proposed related to secondary generation near the tropopause and reflection or secondary generation in the lower stratosphere.
Stratospheric Gravity Waves Generated by Multiscale Tropical Convection
Authors: Lane Todd P. , Moncrieff Mitchell W.
Published: August 2008

The generation of gravity waves by multiscale cloud systems evolving in an initially motionless and thermodynamically uniform environment is explored using a two-dimensional cloud-system-resolving model. The simulated convection has similar depth and intensity to observed tropical oceanic systems. The convection self-organizes into preferred horizontal and temporal scales involving weakly organized propagating cloud clusters. The multiscale systems generate a broad spectrum of gravity waves with horizontal scales that range from the cloud-system scale up to the cloud-cluster scale. The gravity waves with the largest horizontal scale play an important role in modifying layered tropospheric inflow and outflow to the cloud systems, which in turn influence the multiscale convective organization. Slower-moving short-scale gravity waves make the strongest individual contribution to the vertical flux of horizontal momentum and cause a robust peak in the momentum flux spectrum that corresponds to the lifetime and spatial scale of the individual cloud systems.
A Buoyancy–Vorticity Wave Interaction Approach to Stratified Shear Flow
Authors: Harnik N. , Heifetz E. , Umurhan O. M. , Lott F.
Published: August 2008

Motivated by the success of potential vorticity (PV) thinking for Rossby waves and related shear flow phenomena, this work develops a buoyancy–vorticity formulation of gravity waves in stratified shear flow, for which the nonlocality enters in the same way as it does for barotropic/baroclinic shear flows. This formulation provides a time integration scheme that is analogous to the time integration of the quasigeostrophic equations with two, rather than one, prognostic equations, and a diagnostic equation for streamfunction through a vorticity inversion.

The invertibility of vorticity allows the development of a gravity wave kernel view, which provides a mechanistic rationalization of many aspects of the linear dynamics of stratified shear flow. The resulting kernel formulation is similar to the Rossby-based one obtained for barotropic and baroclinic instability; however, since there are two independent variables—vorticity and buoyancy—there are also two independent kernels at each level. Though having two kernels complicates the picture, the kernels are constructed so that they do not interact with each other at a given level.
Dominant Anomaly Patterns in the Near-Surface Baroclinicity and Accompanying Anomalies in the Atmosphere and Oceans. Part I: North Atlantic Basin
Authors: Nakamura Mototaka , Yamane Shozo
Published: August 2008

Variability in the monthly mean flow and storm track in the North Atlantic basin is examined with a focus on the near-surface baroclinicity, B = Bxi + Byj. Dominant patterns of anomalous B found from empirical orthogonal function (EOF) analyses generally show patterns of shift and changes in the strength of B. Composited anomalies in the monthly mean wind at various pressure levels based on the signals in the EOFs display robust accompanying anomalies in the mean flow up to 50 hPa in the winter and up to 100 hPa in other seasons. Anomalous eddy fields accompanying the anomalous Bx patterns exhibit, broadly speaking, structures anticipated from linear theories of baroclinic instabilities and suggest a tendency for anomalous wave fluxes to accelerate/decelerate the surface westerly accordingly. Atmospheric anomalies accompanying By anomalies have patterns different from those that accompany Bx anomalies but are as large as those found for Bx. Anomalies in the sea surface temperature (SST) found for the anomalous patterns of Bx often show large values of small spatial scales along the Gulf Stream (GS), indicating that a meridional shift in the position of the GS and/or changes in the heat transport by the GS may be responsible for the anomalous Bx and concomitant tropospheric and lower-stratospheric anomalies. Anomalies in the net surface heat flux, SST in preceding months, and meridional eddy heat flux in the lower troposphere support this interpretation.
Geometric Calibration of Digital Cameras for 3D Cumulus Cloud Measurements
Authors: Hu Jiuxiang , Razdan Anshuman , Zehnder Joseph A.
Published: August 2008

A technique for calibrating digital cameras for stereo photogrammetry of cumulus clouds is presented. It has been applied to characterize the formation of summer thunderstorms observed during the Cumulus Photogrammetric, In Situ, and Doppler Observations (CuPIDO) project. Starting from gross measurements of locations, orientations of cameras, and landmark surveys, accurate locations and orientations of the cameras are obtained by minimizing a geometric error (GE). Once accurate camera parameters are obtained, 3D positions of cloud-feature points are computed by triangulation.

The main contributions of this paper are as follows. First, it is proven that the GE has only one minimum in the neighborhood of the real parameters of a camera. In other words, searching the minimum of the GE enables the authors to find the right camera parameters even if there are significant differences between the initial measurements and their true values. Second, a new coarse-to-fine iterative algorithm is developed that minimizes the GE and finds the camera parameters. Numerical experiments show that the coarse-to-fine algorithm is efficient and effective. Third, a new landmark survey based on a geographic information system (GIS) rather than field measurements is presented. The GIS landmark survey is an effective and efficient way to obtain landmark world coordinates for camera calibrations in these experiments. Validation of this technique is achieved by the data collected by a NASA/Earth Observing System satellite and an instrumented aircraft. This paper builds on previous research and details the calibration and 3D reconstructions.
Exploiting Anti-Imperialism
Authors: Murdock Michael G.
Published: August 2008

During the Northern Expedition, Guomindang (GMD) policy makers balanced popular anti-imperialism with measures to improve foreign relations. Military pressures meant that top revolutionary leaders could not afford to engage both the warlords and imperialists at the same time, yet rapid advances excited anti-imperialist forces eager to destroy foreign influence once and for all. Opting for security and control, party chiefs restrained popular anti-imperialism. However, when British/warlord collusion produced signs of a Southern Expedition in late December 1926, top party heads released these restraints, encouraging anti-imperialist groups to assail foreign institutions, including the British concessions in Hankou and Jiujiang. Although a great success, the move also caused Britain to initiate troop buildups. Facing new pressures, revolutionary leaders decided to dismantle revolutionary anti-imperialism. In short, mass anti-imperialist organizations were dissolved in April 1927 for practical political reasons that extend beyond factional conflict between the CCP and GMD.
Evaluating Intangible Outcomes
Authors: Selameab Tehout , Yeh Stuart S.
Published: August 2008

Increasingly, program managers are required to evaluate programs with multiple outcomes against costs. This is difficult when program outcomes are not easily translated into a common metric. This article compares cost benefit analysis with Multiple Attribute Utility Technology and discusses the application of judgment in both analytical techniques. Multiple Attribute Utility Technology is illustrated with a case example to demonstrate how it may be applied to evaluate the cost-effectiveness of programs with multiple intangible outcomes.
Principles, Promises, and a Personal Plea
Authors: McDonald Katherine E. , Myrick Shannon E.
Published: August 2008

The client of a student evaluation team has requested that the evaluators provide confidential identifying information gathered in the course of the evaluation. Here, the authors consider their response to the client's request. Specifically, they draw from professional principles developed to guide ethical decision making for evaluators and educators to consider the advantages and disadvantages of denying or meeting this request from a variety of stakeholder perspectives. The authors then use this stakeholder analysis to engage in imaginative thinking about the possible responses from which the student evaluation team can select. They conclude with a review of lessons learned from this challenging situation.
Evaluator Competencies
Authors: Dewey Jennifer D. , Montrosse Bianca E. , Schröter Daniela C. , Sullins Carolyn D. , Mattox John R.
Published: August 2008

This article explores the overlaps and disconnects between the competencies evaluators acquire during graduate school and those required and desired by employers. To investigate this relationship, two different surveys are administered, one for job seekers and the other for employers; 205 postings in the American Evaluation Association job bank were analyzed. The findings suggest that employers, job seekers, and job posters generally agree on the importance of some competencies, such as quantitative analyses and data management. However, some skills desired by employers, such as interpersonal, project management, and presentation skills, differ from skills that job seekers acquire in graduate school. Opportunities for additional experiences in real-world evaluation settings could fill these gaps. Implications for training and future research on training in evaluation are discussed.
On the Validity of Cross-Cultural Social Studies Using Student Samples
Authors: Flere Sergej , Lavrič Miran
Published: August 2008

Student samples have become a widely used resource in the study of not only particular phenomena and problems within individual environments but also of their study within a cross-cultural context. A number of such studies, most often generalizing their results to the level of cultures, are illustrated in this article. In addition, the authors carry out a number of empirical tests of the generalizability of results attained on student samples in cross-cultural research. Based on the World Values Survey data, mean values of four sociologically and psychologically relevant measures are compared between national and student samples of twenty-three countries. Results suggest that the findings attained on student samples can be viewed cautiously as a good indicator of national sample rankings in cross-national comparisons.
Using Tourist Travel Habits and Preferences to Assess Strategic Destination Positioning
Authors: Zhaoping Liu  , Siguaw Judy A. , Enz Cathy A.
Published: August 2008

A study of 118 U.S. travelers to Costa Rica is analyzed to highlight how consumer preferences and patterns of consumption can be used to reveal the status of a particular destination in its life cycle. Using a model for destinations' psychographics developed by S. C. Plog, the analysis shows that Costa Rica may be increasingly appealing to the middle of the psychographic distribution. While this trend is not inherently bad, it challenges Costa Rica's destination managers to consider carefully what type of further development they will allow. This research illustrates the means by which other destinations can assess their own positioning to ensure that they are using strategies to attract the most profitable tourist segments.
Health related quality of life measured by SF-36: a population-based study in Shanghai, China
Authors: Wang Rui , Wu Cheng , Zhao Yanfang , Yan Xiaoyan , Ma Xiuqiang , Wu Meijing , Liu Wenbin , Gu Zheng , Zhao June , He Jia
Published: August 2008

Background

Health related quality of life (HRQL) is a research topic that has attracted increasing interests around the world over the past two decades. The 36-item Short Form (SF-36) is a commonly used instrument for measuring HRQL. However, the information on Chinese adults' quality of life is limited. This paper reports on the feasibility of using the Mandarin version of SF-36 to evaluate HRQL in the population of Shanghai, China.

Methods

A total of 1034 subjects were randomly sampled using a stratified multiple-stage sampling method in Shanghai. Demographic information was collected, and SF-36 was used to measure HRQL.

Results

Internal reliability coefficients were greater than 0.7 in six of the eight SF-36 dimensions, except social function and mental health. Intraclass correlation coefficients ranged from 0.689 to 0.972. Split-half reliability coefficients were higher than 0.9 in five SF-36 dimensions. Validity was assessed by factor analysis and correlation analysis. Our results were basically in accordance with the theoretical construction of SF-36. The average scores of most SF-36 dimensions were higher than 80. The primary influencing risk factors of HRQL included chronic diseases, age, frequency of activities, and geographical region, which were identified using multivariate stepwise regression.

Conclusion

Overall, HRQL in the population of Shanghai is quite good. The Mandarin version of SF-36 is a valid and reliable tool for assessing HRQL.
Phagocytosis of haemozoin (malarial pigment) enhances metalloproteinase-9 activity in human adherent monocytes: Role of IL-1beta and 15-HETE
Authors: Prato Mauro , Gallo Valentina , Giribaldi Giuliana , Arese Paolo
Published: August 2008

Background

It has been shown previously that human monocytes fed with haemozoin (HZ) or trophozoite-parasitized RBCs displayed increased matrix metalloproteinase-9 (MMP-9) enzyme activity and protein/mRNA expression and increased TNF production, and showed higher matrix invasion ability. The present study utilized the same experimental model to analyse the effect of phagocytosis of: HZ, delipidized HZ, beta-haematin (lipid-free synthetic HZ) and trophozoites on production of IL-1beta and MMP-9 activity and expression. The second aim was to find out which component of HZ was responsible for the effects.

Methods

Native HZ freshly isolated from Plasmodium falciparum (Palo Alto strain, Mycoplasma-free), delipidized HZ, beta-haematin (lipid-free synthetic HZ), trophozoites and control meals such as opsonized non-parasitized RBCs and inert latex particles, were fed to human monocytes. The production of IL-1beta by differently fed monocytes, in presence or absence of specific MMP-9 inhibitor or anti-hIL-1beta antibodies, was quantified in supernatants by ELISA. Expression of IL-1beta was analysed by quantitative real-time RT-PCR. MMP-9 activity and protein expression were quantified by gelatin zymography and Western blotting.

Results

Monocytes fed with HZ or trophozoite-parasitized RBCs generated increased amounts of IL-1beta and enhanced enzyme activity (in cell supernatants) and protein/mRNA expression (in cell lysates) of monocyte MMP-9. The latter appears to be causally related to enhanced IL-1beta production, as enhancement of both expression and enzyme activity were abrogated by anti-hIL-1beta Abs. Upregulation of IL-1beta and MMP-9 were absent in monocytes fed with beta-haematin or delipidized HZ, indicating a role for HZ-attached or HZ-generated lipid components. 15-HETE (15(S,R)-hydroxy-6,8,11,13-eicosatetraenoic acid) a potent lipoperoxidation derivative generated by HZ from arachidonic acid via haem-catalysis was identified as one mediator possibly responsible for increase of both IL-1beta production and MMP-9 activity.

Conclusion

Results indicate that specific lipoperoxide derivatives generated by HZ may play a role in modulating production of IL-1beta and MMP-9 expression and activity in HZ/trophozoite-fed human monocytes. Results may clarify aspects of cerebral malaria pathogenesis, since MMP-9, a metalloproteinase able to disrupt the basal lamina is possibly involved in generation of hallmarks of cerebral malaria, such as blood-brain barrier endothelium dysfunction, localized haemorrhages and extravasation of phagocytic cells and parasitized RBCs into brain tissues.
Incidental littoral cell angioma of the spleen
Authors: Tee May , Vos Patrick , Zetler Peter , Wiseman Sam M
Published: August 2008

Background

Littoral cell angioma (LCA) is a recently described primary vascular neoplasm of the spleen that may be associated with other malignancies and may itself also have malignant potential.

Case presentation

We present a case of LCA that was discovered incidentally in a 52-year-old woman who presented with biliary colic at the time of consultation for cholecystectomy. This vascular neoplasm was evaluated by ultrasound, CT, MRI, Tc-99m labelled red blood cell scintigraphy, and core biopsy. A splenectomy revealed LCA by pathological evaluation. Post-operative outcome was favourable with no evidence of complication or recurrent disease. Following this case presentation, clinical, radiographic, and pathological features of LCA will be reviewed as well as recent advances in our understanding of this uncommon splenic lesion.

Conclusion

LCA is a rare, generally benign, primary vascular tumour of the spleen that typically is discovered incidentally. Individuals diagnosed with this tumour must be carefully evaluated to exclude primary, secondary, and synchronous malignancies.
SPECT/CT-plethysmography – non-invasive quantitation of bone and soft tissue blood flow
Authors: Dayan Lior , Keidar Zohar , Israel Ora , Milloul Victor , Sachs Johnathan , Jacob Giris
Published: August 2008

Preserved blood flow to bone and soft tissue is essential for their normal function. To date only numerous methods are suitable for direct bone blood flow (BBF) measurement. Here, we introduce a novel quantitative method for bone and soft tissue blood flow (BBF and SBF, respectively) measurement. It involves a combination of SPECT/CT imaging for blood pool localization in a specific region of interest ("soft" and "hard" tissues composing a limb) with veno-occlusive plethysmography. Using it, we measured BBF and SBF in the four limbs of 10 healthy subjects. At steady state blood flow measurements in the four limbs were similar, ranging between 5.5 – 6.5 and 1.87–2.48 ml per 100 ml of tissue per minute for BBF and SBF, respectively. Our results are comparable to those in the literature. We concluded that SPECT/CT-plethysmography appears to be a readily available and easy to use method to measure BBF and SBF, and can be added to the armamentarium of methods for BBF measurements.
Giant cell tumour in the diaphysis of radius – a report
Authors: Shrivastava Sandeep , Nawghare Shishir P , Kolwadkar Yogesh , Singh Pradeep
Published: August 2008

Background

We present a case of a 35 yrs old female who presented with swelling over her forearm. This is a rare case of a giant cell tumour in a nonepiphyseal region.

Methods

Case report and presentation of clinical, radiological and histological data on single case of giant cell tumour of diaphysis of radius.

Results

Although age, clinical features and radiological features are helpful, it is still the histology that helps to clinch the diagnosis.

Conclusion

A thorough literature search and an exhaustive online search using various search engines revealed seven reported cases of giant cell tumours in the diaphysis of long bones. We reiterate the fact that irrespective of the location, a giant cell tumour should be diagnosed based on its histology.
Integrative analyses of genetic variation in enzyme activities of primary carbohydrate metabolism reveal distinct modes of regulation in Arabidopsis thaliana
Authors: Keurentjes Joost JB , Sulpice Ronan , Gibon Yves , Steinhauser Marie-Caroline , Fu Jingyuan , Koornneef Maarten , Stitt Mark , Vreugdenhil Dick
Published: August 2008

Background

Plant primary carbohydrate metabolism is complex and flexible, and is regulated at many levels. Changes of transcript levels do not always lead to changes in enzyme activities, and these do not always affect metabolite levels and fluxes. To analyze interactions between these three levels of function, we have performed parallel genetic analyses of 15 enzyme activities involved in primary carbohydrate metabolism, transcript levels for their encoding structural genes, and a set of relevant metabolites. Quantitative analyses of each trait were performed in the Arabidopsis thaliana Ler × Cvi recombinant inbred line (RIL) population and subjected to correlation and quantitative trait locus (QTL) analysis.

Results

Traits affecting primary metabolism were often correlated, possibly due to developmental control affecting multiple genes, enzymes, or metabolites. Moreover, the activity QTLs of several enzymes co-localized with the expression QTLs (eQTLs) of their structural genes, or with metabolite accumulation QTLs of their substrates or products. In addition, many trait-specific QTLs were identified, revealing that there is also specific regulation of individual metabolic traits. Regulation of enzyme activities often occurred through multiple loci, involving both cis- and trans-acting transcriptional or post-transcriptional control of structural genes, as well as independently of the structural genes.

Conclusion

Future studies of the regulatory processes in primary carbohydrate metabolism will benefit from an integrative genetic analysis of gene transcription, enzyme activity, and metabolite content. The multiparallel QTL analyses of the various interconnected transducers of biological information flow, described here for the first time, can assist in determining the causes and consequences of genetic regulation at different levels of complex biological systems.
Sacred Geographies: Religion and Race in Women's Holy Land Writings
Authors: Robey Molly
Published: August 2008

U.S. women's Holy Land writings—a body of novels, travel narratives, and children's literature—uniquely illustrate Americans' complex and often conflicting imperialist and religious investments in the Near East. U.S. women writers embraced the Holy Land as an extranational domestic space, a spiritual and prenational homeland that empowered American women as their nation's presumed spiritual guardians. From the 1840s through the 1890s, the American woman that was represented in women's Holy Land writings bound and reconciled the political and spiritual forces at work in the Holy Land, especially during times of national vulnerability. In the late 1850s and 1860, when the outbreak of sectarian violence in Mount Lebanon provoked further anxiety about growing sectional and racial hostilities in the United States, women writers imagined the American woman capable of reordering a contentious, religiously diverse society. The multicultural community that women writers envisioned, however, was founded on the subordination of religious and racial others; moreover, women's Holy Land writings conflated religious and racial otherness as a way of containing difference. The Muslim-Arab became the emblem of this conflation, a figure both immoral and unalterable. Despite the dangers this Muslim-Arab posed to diverse society, he was represented as mollified by the American woman's pious presence. An inherent deference for U.S. domesticity, these women writers suggested, can compel religious-racial others to submit willingly to a clearly hierarchized social order. Innate piety enabled the American woman to reconfigure class in the Holy Land and make diversity safe, in turn reinforcing the Holy Land as a feminine domain.
“Object into Subject”: Michelle Cliff, John Ruskin, and the Terrors of Visual Art
Authors: Walters Wendy W.
Published: August 2008

This essay juxtaposes two readings of J. M. W. Turner's 1840 painting, Slavers Throwing Overboard the Dead and Dying, Typhoon Coming On: one by British art historian John Ruskin and the other by contemporary Jamaican novelist Michelle Cliff. To examine the racial and national politics of visual spectatorship, the essay analyzes Cliff's novel Free Enterprise (1993); the central scene is an unveiling of this painting. Destabilizing Ruskin's reading of the painting's sublimity and asking what it means to “take pleasure in looking at images of terror,” Cliff's novel inserts a black viewer as the subject, not the object, of history. In contrast to Ruskin's writings that enshrine an English identity that would sublimate its specific relationship to slavery, the writings of contemporary postcolonial novelists such as Cliff articulate diasporic identities that interrogate such constructions, complicating the relationship between history and memory. Engaging with the archives of American history, Cliff's novel restores the resistant acts that have been pushed into the background, focusing on rewriting the history of Mary Ellen Pleasant. Between the two national identities Jamaican and British, Cliff inserts an American rebellious subject, Mary Ellen Pleasant. Pleasant's oppositional gaze on Turner's painting constructs a countermemory of new world black resistance and reminds us of the ways that diasporic identities are always already a part of the nation's identity.
Salvaging History: Modern Philosophies of Memory and Time in The Age of Innocence
Authors: Klimasmith Betsy
Published: August 2008

This essay reads Edith Wharton's novel The Age of Innocence (1920) not as an escapist response to the First World War but, in its exploration of modern scientific and philosophical conceptions of time and memory as articulated by Albert Einstein and Henri Bergson, an exploration of the emotional trauma wrought by the war and a proposal for how the modern world might recover and move forward. Cannily manipulating time within the accessible form of the historical novel, Wharton makes readable a version of modern consciousness in which behavior and emotion, public time and private time, tradition and change coexist. For most readers, the novel's genre, style, setting, and author preclude it from being considered a modernist text; however, this essay argues that Wharton's subtle manipulation of historical detail along with her engagement with the philosophy of memory and the physics of time make The Age of Innocence her most successful literary experiment and position it as a major modern literary response to the First World War.
A New Era of Turbulence in the Balkans?
Authors: Carpenter Ted Galen
Published: August 2008

Ted Galen Carpenter is vice president for defense and foreign policy studies at the Cato Institute and author of Smart Power: Toward a Prudent Foreign Policy for America.
American Foreign Policy After Iraq
Authors: Pranger Robert J.
Published: August 2008

Robert J. Pranger is a private consultant with extensive experience in national security affairs. He was formerly associate/managing editor of Mediterranean Quarterly.
An Agenda for the Next American President
Authors: Fouskas Vassilis K. , Gökay Bülent
Published: August 2008

Vassilis K. Fouskas is professor of international relations at the University of Piraeus and the editor of the Journal of Southern Europe and the Balkans. Bülent Gökay is professor of international relations at Keele University and the editor of Eurasian Studies Network.