Social vs. practical problems in attaining a colonoscopy: Different patient profiles?

Background: Colonoscopy is an effective procedure for identifying precancerous polyps and cancerous lesions, but it is unlike other cancer screening tools in that it requires sedation and thus assistance from at least one other individual. The intent of this paper was to identify logistical problems in completing the colonoscopy and to examine their relationships with sociodemographic characteristics. Methods: All eligible patients (n = 2500) from two academic-affiliated colonoscopy centers (one free standing, one hospital-based) were invited to participate in an onsite, pre-colonoscopy survey; patients agreeing to participate (n = 1841, RR = 73.6%) received a $5.00 gift card. Multiple correspondence analysis (MCA) was used to identify the underlying dimensional structure of the problems. Bivariate statistics were performed to compare demographic variables and health literacy levels among patients reporting problems. Multivariate logistic regression with a backwards conditional solution was used to determine the demographic variables independently associated with problems. Results: Multiple correspondence analyses indicated two dimensions of problems (social and practical). Using logistic regression, social problems (e.g., finding someone to accompany the patient) were associated with not living in the same home as the driver, not working due to disability, and younger age. Practical problems (e.g., making an appointment) were associated with “other” minority race, poorer health, lower health literacy, and younger age. Conclusion: Patients experience different problems completing the colonoscopy based on socio-demographics. Particularly at risk are patients who find it difficult to navigate the system, are of younger age, or who may have smaller social networks

Fragmentation, Factorization and Infrared Poles in Heavy Quarkonium Production

We explore the role of soft gluon exchange in heavy quarkonium production at large transverse momentum. We find uncanceled infrared poles at NNLO that are not matched by conventional NRQCD matrix elements. We show, however, that gauge invariance and factorization require that conventional NRQCD production operators be modified to include nonabelian phases or Wilson lines. With appropriately modified operators, factorization is restored at NNLO. We also argue that, in the absence of special cancellations, infrared poles at yet higher orders may require the inclusion of additional nonlocal operators, not present in the NRQCD expansion in relative veloctiy.Comment: 10 pages latex, 6 eps figure

A tuple space web service for distributed programming.

Abstract: This paper describes a new tuple space web service for coordination and communication in distributed web applications. This web service is based on the Linda programming model. Linda is a coordination language for parallel and distributed processing, providing a communication mechanism based on a logically shared memory space. The original Linda model has been extended through the provision of a programmable mechanism, providing additional flexibility and improved performance. The implementation of the web service is discussed, together with the details of the programmable matching mechanism. Some results from the implementation of a location-based mobile application, using the tuple space web service are presented, demonstrating the benefits of our system

A tuple space web service for distributed programming-Simplifying distributed web services applications

This paper describes a new tuple space web service for coordination and communication in distributed web applications. This web service is based on the Linda programming model. Linda is a coordination lan-guage for parallel and distributed processing, providing a communica-tion mechanism based on a logically shared memory space. The origi-nal Linda model has been extended through the provision of a pro-grammable mechanism, providing additional flexibility and improved performance. The implementation of the web service is discussed, to-gether with the details of the programmable matching mechanism. Some results from the implementation of a location-based mobile appli-cation, using the tuple space web service are presented, demonstrating the benefits of our system

Intrinsic response time of graphene photodetectors

Graphene-based photodetectors are promising new devices for high-speed optoelectronic applications. However, despite recent efforts, it is not clear what determines the ultimate speed limit of these devices. Here, we present measurements of the intrinsic response time of metal-graphene-metal photodetectors with monolayer graphene using an optical correlation technique with ultrashort laser pulses. We obtain a response time of 2.1 ps that is mainly given by the short lifetime of the photogenerated carriers. This time translates into a bandwidth of ~262 GHz. Moreover, we investigate the dependence of the response time on gate voltage and illumination laser power

The Validity of Studies with Line of Business Data: Comment

In the March 1985 issue of this Review, George Benston found fault with Federal Trade Commission Line of Business (LB) data generally and singled out for extended criticism thirteen LB data-based papers written by the authors of this comment. Even by the pre-Queensberry rules governing eco- nomic disputation, Benston\u27s article is one- sided and negative. Moreover, it is marred by numerous errors in characterizing our work. We wish to set the record straight

Space-filling and benthic competition on coral reefs

Reef-building corals are ecosystem engineers that compete with other benthic organisms for space and resources. Corals harvest energy through their surface by photosynthesis and heterotrophic feeding, and they divert part of this energy to defend their outer colony perimeter against competitors. Here, we hypothesized that corals with a larger space-filling surface and smaller perimeters increase energy gain while reducing the exposure to competitors. This predicted an association between these two geometric properties of corals and the competitive outcome against other benthic organisms. To test the prediction, fifty coral colonies from the Caribbean island of Curaçao were rendered using digital 3D and 2D reconstructions. The surface areas, perimeters, box-counting dimensions (as a proxy of surface and perimeter space-filling), and other geometric properties were extracted and analyzed with respect to the percentage of the perimeter losing or winning against competitors based on the coral tissue apparent growth or damage. The increase in surface space-filling dimension was the only significant single indicator of coral winning outcomes, but the combination of surface space-filling dimension with perimeter length increased the statistical prediction of coral competition outcomes. Corals with larger surface space-filling dimensions (Ds > 2) and smaller perimeters displayed more winning outcomes, confirming the initial hypothesis. We propose that the space-filling property of coral surfaces complemented with other proxies of coral competitiveness, such as life history traits, will provide a more accurate quantitative characterization of coral competition outcomes on coral reefs. This framework also applies to other organisms or ecological systems that rely on complex surfaces to obtain energy for competition

Photo-Thermoelectric Effect at a Graphene Interface Junction

We investigate the optoelectronic response of a graphene interface junction, formed with bilayer and single-layer graphene, by photocurrent (PC) microscopy. We measure the polarity and amplitude of the PC while varying the Fermi level by tuning a gate voltage. These measurements show that the generation of PC is by a photo-thermoelectric effect. The PC displays a factor of ~10 increase at the cryogenic temperature as compared to room temperature. Assuming the thermoelectric power has a linear dependence on the temperature, the inferred graphene thermal conductivity from temperature dependent measurements has a T^{1.5} dependence below ~100 K, which agrees with recent theoretical predictions