A Utility-Based Approach to Bandwidth Allocation and Link Scheduling in Wireless Networks

We study the problem of optimizing aggregate user utility in wireless ad-hoc networks under the constraints of wireless interference. We develop a market-oriented approach to bandwidth allocation with a tˆatonnement process and demonstrate its ability to effectively price bottleneck resource. One novelty is that we choose to price “interference goods” to capture the externality imposed by one application’s use of the network on other applications. In making progress we also propose a modification to the CSMA protocol that is robust enough to handle a non-schedulable bandwidth schedule. Experimental results on simulated network topologies show that the market-based approach has better scalability than alternate approximation methods and is much more efficient in terms of runtime.Engineering and Applied Science

Are goal states represented during kinematic imitation?

A number of studies have shown that observation of another person's actions can modulate one's own actions, such as when 2 individuals cooperate in order to complete a joint task. However, little is known about whether or not direct matching of specific movements is modulated by the goals of the actions observed. In a series of 7 experiments, we employed an action observation paradigm in which 2 coactors sat opposite each other and took turns to reach out to targets presented on a shared workspace. Importantly, coactors performed either the same goal at the reached-to location or a different goal. Although results consistently showed that the reaching action of 1 individual slows the observer's reaching action to the same spatial location, the effect was not modulated according to the adopted goals of coactors. These findings challenge the notion that the processes involved in the imitation of specific movements code for the action goals of those movements

Towards More Data-Aware Application Integration (extended version)

Although most business application data is stored in relational databases, programming languages and wire formats in integration middleware systems are not table-centric. Due to costly format conversions, data-shipments and faster computation, the trend is to "push-down" the integration operations closer to the storage representation. We address the alternative case of defining declarative, table-centric integration semantics within standard integration systems. For that, we replace the current operator implementations for the well-known Enterprise Integration Patterns by equivalent "in-memory" table processing, and show a practical realization in a conventional integration system for a non-reliable, "data-intensive" messaging example. The results of the runtime analysis show that table-centric processing is promising already in standard, "single-record" message routing and transformations, and can potentially excel the message throughput for "multi-record" table messages.Comment: 18 Pages, extended version of the contribution to British International Conference on Databases (BICOD), 2015, Edinburgh, Scotlan

Critical Structure Sparing in Stereotactic Ablative Radiotherapy for Central Lung Lesions: Helical Tomotherapy vs. Volumetric Modulated Arc Therapy

Background Helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT) are both advanced techniques of delivering intensity-modulated radiotherapy (IMRT). Here, we conduct a study to compare HT and partial-arc VMAT in their ability to spare organs at risk (OARs) when stereotactic ablative radiotherapy (SABR) is delivered to treat centrally located early stage non-small-cell lung cancer or lung metastases. Methods 12 patients with centrally located lung lesions were randomly chosen. HT, 2 & 8 arc (Smart Arc, Pinnacle v9.0) plans were generated to deliver 70 Gy in 10 fractions to the planning target volume (PTV). Target and OAR dose parameters were compared. Each technique’s ability to meet dose constraints was further investigated. Results HT and VMAT plans generated essentially equivalent PTV coverage and dose conformality indices, while a trend for improved dose homogeneity by increasing from 2 to 8 arcs was observed with VMAT. Increasing the number of arcs with VMAT also led to some improvement in OAR sparing. After normalizing to OAR dose constraints, HT was found to be superior to 2 or 8-arc VMAT for optimal OAR sparing (meeting all the dose constraints) (p = 0.0004). All dose constraints were met in HT plans. Increasing from 2 to 8 arcs could not help achieve optimal OAR sparing for 4 patients. 2/4 of them had 3 immediately adjacent structures. Conclusion HT appears to be superior to VMAT in OAR sparing mainly in cases which require conformal dose avoidance of multiple immediately adjacent OARs. For such cases, increasing the number of arcs in VMAT cannot significantly improve OAR sparing

High Transmitter CD4+ T-Cell Count Shortly after the Time of Transmission in a Study of African Serodiscordant Couples.

© 2015 Karita et al.Background: 2013 WHO guidelines recommend starting ART at CD4+ T-cell counts ≤500 cells/μL. We present the T-cell counts from adult Africans with HIV shortly following transmission to their sexual partners. Methods: HIV-discordant couples in Zambia, Uganda and Rwanda were followed prospectively and received couples counseling and condoms. HIV uninfected partners were tested for HIV at least quarterly and HIV-infected partners received HIV care and referral for ART per national guidelines. Upon diagnosis of incident HIV infection in the previously HIV-uninfected partner, a blood sample was collected from both partners to measure CD4+ T-cells and perform viral linkage. The estimated date of infection (EDI) of the incident case was calculated based on testing history. EDI was unknown for suspected transmitting partners. Results: From 2006-2011, 4,705 HIV-discordant couples were enrolled in this cohort, and 443 cases of incident HIV infection were documented. Virus linkage analysis was performed in 374 transmission pairs, and 273 (73%) transmissions were linked genetically. CD4 counts in the transmitting partner were measured a median of 56 days after EDI (mean:90.5, min:10, max:396). The median CD4 count was 339 cells/μl (mean:386.4, min:15, max:1,434), and the proportion of partners with a CD4+ T-cell count above 500/μl was 25% (95% CI:21, 31). Conclusions: In our cohort of discordant couples, 73% of HIV transmissions occurred within the relationship, and the transmitter CD4+ T cell count shortly after the transmission event was frequently higher than the WHO 2013 ART-initiation guidelines. Copyright

Repeatability and sensitivity of T2* measurements in patients with head and neck squamous cell carcinoma at 3T.

Purpose To determine whether quantitation of T2* is sufficiently repeatable and sensitive to detect clinically relevant oxygenation levels in head and neck squamous cell carcinoma (HNSCC) at 3T.Materials and methods Ten patients with newly diagnosed locally advanced HNSCC underwent two magnetic resonance imaging (MRI) scans between 24 and 168 hours apart prior to chemoradiotherapy treatment. A multiple gradient echo sequence was used to calculate T2* maps. A quadratic function was used to model the blood transverse relaxation rate as a function of blood oxygenation. A set of published coefficients measured at 3T were incorporated to account for tissue hematocrit levels and used to plot the dependence of fractional blood oxygenation (Y) on T2* values, together with the corresponding repeatability range. Repeatability of T2* using Bland-Altman analysis, and calculation of limits of agreement (LoA), was used to assess the sensitivity, defined as the minimum difference in fractional blood oxygenation that can be confidently detected.Results T2* LoA for 22 outlined tumor volumes were 13%. The T2* dependence of fractional blood oxygenation increases monotonically, resulting in increasing sensitivity of the method with increasing blood oxygenation. For fractional blood oxygenation values above 0.11, changes in T2* were sufficient to detect differences in blood oxygenation greater than 10% (Δ T2* > LoA for ΔY > 0.1).Conclusion Quantitation of T2* at 3T can detect clinically relevant changes in tumor oxygenation within a wide range of blood volumes and oxygen tensions, including levels reported in HNSCC. J. Magn. Reson. Imaging 2016;44:72-80

Physiotherapy for Parkinson's disease: a comparison of techniques (Review)

Background: Despite medical therapies and surgical interventions for Parkinson's disease (PD), patients develop progressive disability. The role of physiotherapy is to maximise functional ability and minimise secondary complications through movement rehabilitation within a context of education and support for the whole person. The overall aim is to optimise independence, safety and wellbeing, thereby enhancing quality of life. Trials have shown that physiotherapy has short-term benefits in PD. However, which physiotherapy intervention is most effective remains unclear. Objectives: To assess the effectiveness of one physiotherapy intervention compared with a second approach in patients with PD. Search methods: Relevant trials were identified by electronic searches of numerous literature databases (for example MEDLINE, EMBASE) and trial registers, plus handsearching of major journals, abstract books, conference proceedings and reference lists of retrieved publications. The literature search included trials published up to the end of January 2012. Selection criteria: Randomised controlled trials of one physiotherapy intervention versus another physiotherapy intervention in patients with PD. Data collection and analysis: Data were abstracted independently from each paper by two authors. Trials were classified into the following intervention comparisons: general physiotherapy, exercise, treadmill training, cueing, dance and martial arts. Main results: A total of 43 trials were identified with 1673 participants. All trials used small patient numbers (average trial size of 39 participants); the methods of randomisation and concealment of allocation were poor or not stated in most trials. Blinded assessors were used in just over half of the trials and only 10 stated that they used intention-to-treat analysis.A wide variety of validated and customised outcome measures were used to assess the effectiveness of physiotherapy interventions. The most frequently reported physiotherapy outcomes were gait speed and timed up and go, in 19 and 15 trials respectively. Only five of the 43 trials reported data on falls (12%). The motor subscales of the Unified Parkinson?s Disease Rating Scale and Parkinson?s Disease Questionnaire-39 were the most commonly reported clinician-rated disability and patient-rated quality of life outcome measures, used in 22 and 13 trials respectively. The content and delivery of the physiotherapy interventions varied widely in the trials included within this review, so no quantitative meta-analysis could be performed. Authors' conclusions: Considering the small number of participants examined, the methodological flaws in many of the studies, the possibility of publication bias, and the variety of interventions, formal comparison of the different physiotherapy techniques could not be performed. There is insufficient evidence to support or refute the effectiveness of one physiotherapy intervention over another in PD.This review shows that a wide range of physiotherapy interventions to treat PD have been tested . There is a need for more specific trials with improved treatment strategies to underpin the most appropriate choice of physiotherapy intervention and the outcomes measured

Assessing historical realibility of the agent-based model of the global energy system

This study looks at the historical reliability of the agent-based model of the global energy system. We present a mathematical framework for the agent-based model calibration and sensitivity analysis based on historical observations. Simulation consistency with the historical record is measured as a distance between two vectors of data points and inference on parameter values is done from the probability distribution of this stochastic estimate. Proposed methodology is applied to the model of the global energy system. Some model properties and limitations followed from calibration results are discussed