Developments in the simulation of compressible inviscid and viscous flow on supercomputers

In anticipation of future supercomputers, finite difference codes are rapidly being extended to simulate three-dimensional compressible flow about complex configurations. Some of these developments are reviewed. The importance of computational flow visualization and diagnostic methods to three-dimensional flow simulation is also briefly discussed

The Evolution of Active Sport Event Travel Careers

Using the event-travel-career concept, this study examined the trajectory of active-sport-event travel careers through stages of development and the corresponding factors and dimensions perceived to influence career progression in the sport of cycling. In-depth semistructured interviews were conducted with 12 amateur cyclists engaged in lifestyles geared toward active event travel. A grounded theory approach revealed that active event travel careers evolve through a complex progression of 9 core themes and related subthemes. The core themes included the first event, starting out, motivation, temporal, travel style, destination criteria, event types, spatial, and later in life. On the basis of these findings, a 6-stage active-sport-event travel career model is proposed consisting of initiation, introduction, expansion, peak threshold, maintenance, and maturity. From this model, theoretical contributions, suggestions for future research, and practical implications for sport tourism and event management are discussed

The Role of Travel Conditions in Cycling Tourism: Implications for Destination and Event Management

The purpose of this study was to explore the influence of travel conditions on preferred destination, event, and travel characteristics in the context of Active-Sport-Event Travel Carers among cyclists who travel to take part in events. Travel conditions are circumstances surrounding a trip such as travel with family or the length of travel. A sample of cyclists that travel to participate in events (N = 1452) was collected via online survey through cycling organizations and websites. Data analysis consisted of a series of repeated measures ANOVAs and paired sample t-tests. The results indicated an individual's event, destination, and travel-style preferences are dependent on whether he or she was traveling with a non-cyclist (e.g. family member) and the distance traveled. Prior research has suggested that for active sport tourists event criteria are more important than destination characteristics and travel preferences remain relatively stagnant with career progression. In contrast, the findings here suggest travel preferences vary based on travel conditions and that attractive destinations only become advantageous if event participants are traveling with non-cyclists or on trips involving longer distances. For instance when non-participant travel companions are included, the entertainment, attractions, and activities available in the destination become much more important to active event tourists. Communities seeking to attract sport tourists as a form of sustainable tourism development would be advised to organize events incorporating these preferences and to consider the influence of travel conditions

Visitor bikeshare usage: tracking visitor spatiotemporal behavior using big data

Bikeshare programs are a popular, convenient, and sustainable mode of transportation that provide a range of benefits to urban communities such as reduction in carbon emissions, decreased travel times, financial savings, and heightened physical activity. Although, tourists are especially inclined to use bikeshare to explore a destination as the programs are a convenient, cheap, flexible, and an active alternative to vehicles and mass transit little research or attention has focused on visitor usage. As such the current study investigated the spatial-temporal usage patterns of bikeshare by visitors to an urban community using GPS based big data (N = 353,733). The results revealed differential usage patterns between visitors and local residents based on user provided ZIP Codes using a 50 mile geometric circular buffer around the urban destination. The visitors and residents significantly varied on numerous trip behaviors including route selection, time of rental, checkout/check-in locations, distance, speed, duration, and physical activity intensity. The user patterns uncovered suggest visitors primarily use bikeshare for leisure based urban exploration, compared to residents’ primary use of bikeshare to be public transportation related. Implications for bikeshare, urban planning, and tourism management are provided aimed at delivering a more sustainable and richer visitor experience

Participation Versus Nonparticipation in a Charity Running Event

Hosting sport events to raise money for charitable causes has become pervasive, yet we know little about why individuals choose to participate or not. This study examined the differences between participants and nonparticipants of a hallmark small-scale charity running event. Data were collected via an online survey containing measures of charity event participation frequency, enduring involvement, negotiation efficacy, family support, running participation patterns, and demographics. Nonparticipants were also asked about event-related participation constraints. The sample was comprised of N = 322 event participants and N = 112 nonparticipants (committed runners). A one-way ANOVA demonstrated no statistically significant differences between the two independent samples with respect to the variables of interest. Nonparticipants indicated relatively low constraints to event participation. The most commonly reported constraints solicited in an open-ended question format were injuries and participation in an alternative event. Findings revealed that event participants and nonparticipants are very similar in terms of their running participation patterns. However, definite nonnegotiable constraints or preplanned involvement with other events inhibited participation in the studied event. Over time, this can result in either the expansion or contraction of their involvement in the running event. By illuminating nonnegotiable constraints, this study may help event organizers improve planning and management towards event sustainability

spFRET Using Alternating Excitation and FCS Reveals Progressive DNA Unwrapping in Nucleosomes

AbstractAccessibility to DNA wrapped in nucleosomes is essential for nuclear processes such as DNA transcription. Large conformational changes in nucleosome structure are required to facilitate protein binding to target sites within nucleosomal DNA. Transient unwrapping of DNA from nucleosome ends can provide an intrinsic exposure of wrapped DNA, allowing proteins to bind DNA that would otherwise be occluded in the nucleosome. The molecular details underlying these mechanisms remain to be resolved. Here we show how DNA unwrapping occurs progressively from both nucleosome ends. We performed single-pair fluorescence resonance energy transfer (spFRET) spectroscopy with alternating laser excitation (ALEX) on nucleosomes either in free solution or confined in a gel after PAGE separation. We combined ALEX-spFRET with a correlation analysis on selected bursts of fluorescence, to resolve a variety of unwrapped nucleosome conformations. The experiments reveal that nucleosomes are unwrapped with an equilibrium constant of ∼0.2–0.6 at nucleosome ends and ∼0.1 at a location 27 basepairs inside the nucleosome, but still remain stably associated. Our findings, obtained using a powerful combination of single-molecule fluorescence techniques and gel electrophoresis, emphasize the delicate interplay between DNA accessibility and condensation in chromatin

A Monte Carlo study of the three-dimensional Coulomb frustrated Ising ferromagnet

We have investigated by Monte-Carlo simulation the phase diagram of a three-dimensional Ising model with nearest-neighbor ferromagnetic interactions and small, but long-range (Coulombic) antiferromagnetic interactions. We have developed an efficient cluster algorithm and used different lattice sizes and geometries, which allows us to obtain the main characteristics of the temperature-frustration phase diagram. Our finite-size scaling analysis confirms that the melting of the lamellar phases into the paramgnetic phase is driven first-order by the fluctuations. Transitions between ordered phases with different modulation patterns is observed in some regions of the diagram, in agreement with a recent mean-field analysis.Comment: 14 pages, 10 figures, submitted to Phys. Rev.

Multi-functional annular fairing for coupling launch abort motor to space vehicle

An annular fairing having aerodynamic, thermal, structural and acoustic attributes couples a launch abort motor to a space vehicle having a payload of concern mounted on top of a rocket propulsion system. A first end of the annular fairing is fixedly attached to the launch abort motor while a second end of the annular fairing is attached in a releasable fashion to an aft region of the payload. The annular fairing increases in diameter between its first and second ends

Flow characterisation for a validation study in high-speed aerodynamics

Validation studies are becoming increasingly relevant when investigating complex flow problems in high-speed aerodynamics. These investigations require calibration of numerical models with accurate data from the physical wind tunnel being studied. This paper presents the characterisation process for a joint experimental-computational study to investigate the streamwise corners of a Mach 2.5 channel flow. As well as checks of flow quality typically performed for phenomenological investigations, additional quantitative tests are conducted. The extra care to obtain high quality data and eliminate any systematic errors reveal useful information about the wind tunnel flow. Further important physical insights are gained from designing and conducting wind tunnel tests in conjunction with numerical simulations. Crucially, the close experimental-computational collaboration enabled the identification of secondary flows in the sidewall boundary-layers; these strongly influence the flow in the corner regions, the target of the validation study

Reactivity to human papillomavirus type 16 Ll virus-like particles in sera from patients with genital cancer and patients with carcinomas at five different extragenital sites

A retrospective seroepidemiologic study was performed to examine the association between human papillomaviruses (HPV) 16 infection and carcinomas of the oropharynx, the oesophagus, penis and vagina. Sera were selected from the serum bank from the Antoni van Leeuwenhoek Hospital (Netherlands Cancer Institute) and the Slotervaart Hospital in Amsterdam, the Netherlands. Presence of HPV 16 specific antibody was assessed using HPV 16 L1 capsids. Sera positive for HPV 16 capsid antibody were further tested for antibody against HPV 16 E7 peptides. Prevalence of antibody against H PV 16 L1 capsids among both the negative control group without cancer and the negative control group with gastric cancer was 18%, while seroprevalence among the control group of patients with HPV-associated cervical squamous cell carcinoma was 47% (P < 0.001). Among the patients with penile squamous cell carcinoma seroprevalence was 38% (P < 0.001), among patients with oropharyngeal carcinoma 33% (P = 0.04) and among patients with oesophageal squamous cell carcinoma 14% (P = 0.7). The serological evidence for association between HPV 16 infection and both oropharyngeal carcinoma and penile carcinoma was established. The conclusion that no association was found between the presence of antibody against HPV 16 L1 capsids and oesophageal squamous cell carcinoma was in accordance with results of other studies carried out in the Netherlands using HPV DNA technology. In the subjects with HPV 16 L1 capsid antibody, no association was found between the antibody against HPV 16 E7 and clinical outcome