On the flow-level stability of data networks without congestion control: the case of linear networks and upstream trees

In this paper, flow models of networks without congestion control are considered. Users generate data transfers according to some Poisson processes and transmit corresponding packet at a fixed rate equal to their access rate until the entire document is received at the destination; some erasure codes are used to make the transmission robust to packet losses. We study the stability of the stochastic process representing the number of active flows in two particular cases: linear networks and upstream trees. For the case of linear networks, we notably use fluid limits and an interesting phenomenon of "time scale separation" occurs. Bounds on the stability region of linear networks are given. For the case of upstream trees, underlying monotonic properties are used. Finally, the asymptotic stability of those processes is analyzed when the access rate of the users decreases to 0. An appropriate scaling is introduced and used to prove that the stability region of those networks is asymptotically maximized

Quality of life associated factors in head and neck cancer patients in a developing country using the FACT-H&N

Health-related quality of life (HRQoL) associated factors are vital considerations prior to treatment decision-making for head and neck cancer patients. The study aimed to identify potential socio-demographic and clinical prognostic value of HRQoL in head and neck cancer patients in a developing country. The Functional Assessment of Cancer Therapy-Head and Neck (FACT-H&N)-V4 in Urdu language was administered among 361 head and neck cancer patients. Data were statistically tested through multivariate analysis of variance (MANOVA) and regression modeling to identify the potentially associated factors. Treatment status, tumor stage and tumor site had the strongest negative impact on patients HRQoL, with a statistically significant decrement in FACT summary scales (effect size >0.15). Moderate associated factors of HRQoL included treatment type, marital status, employment status and age (effect size range 0.06-0.15). Weak associated factors of HRQoL with a small effect size (>0.01-0.06) included tumor size and type, gender, education level and ethnicity. This study reports 12 socio-demographic and clinical variables that have a significant impact on HRQoL of head, and neck cancer patients, and that should be considered during treatment decision-making by multidisciplinary teams and also in future HRQoL studies conducted in other developing countries. (C) 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd

Stochastic B\"acklund transformations

How does one introduce randomness into a classical dynamical system in order to produce something which is related to the `corresponding' quantum system? We consider this question from a probabilistic point of view, in the context of some integrable Hamiltonian systems

Using a patient prompt list to raise concerns in oncology clinics does not necessarily lead to longer consultations

Head and neck oncology post-treatment consultations form a critical component of care in terms of support and surveillance. They occur frequently in the first few years and can place substantial demands on healthcare resources. However, they provide useful opportunities for patients to raise issues and receive tailored information and support. The aim of this paper was to assess whether completion of a 56-item patient prompt list (PCI - the Patient Concerns Inventory) immediately prior to the consultation significantly increased its duration. This was a pragmatic cluster preference randomised controlled trial of 288 patients with 15 consultant clusters from two sites “using” (n = 8) or “not using” (n = 7) the PCI. Consultation times were known for 283 patients (136 PCI, 147 non-PCI) who attended their first post-treatment trial consultation a median (IQR) of 103 (70-160) days after the end of treatment. Consultations lasted a median (IQR) of 10 (7-13) minutes (mean 11) in non-PCI patients and a median (IQR) of 11 (8-15) minutes (mean 12) in PCI patients (p = 0.07). After adjustment for patient clustering and significant case mix, the 95% confidence interval for the mean difference was between 1.45 minutes shorter with the PCI and 2.98 minutes longer (p = 0.50). There was significant variation in duration by consultant, tumour stage, treatment mode, overall quality of life (QoL), and distress (all p < 0.001). In those who completed the PCI, duration increased with the total number of items selected (p < 0.001). In conclusion, the inclusion of a prompt list to help facilitate conversation with patients did not make a substantial difference to consultation times

SUSY vertex algebras and supercurves

This article is a continuation of math.QA/0603633 Given a strongly conformal SUSY vertex algebra V and a supercurve X we construct a vector bundle V_X on X, the fiber of which, is isomorphic to V. Moreover, the state-field correspondence of V canonically gives rise to (local) sections of these vector bundles. We also define chiral algebras on any supercurve X, and show that the vector bundle V_X, corresponding to a SUSY vertex algebra, carries the structure of a chiral algebra.Comment: 50 page

Disease trajectories, place and mode of death in people with head and neck cancer: findings from the ‘Head and Neck 5000’ population-based prospective clinical cohort study

Background: Few large studies describe initial disease trajectories and subsequent mortality in people with head and neck cancer. This is a necessary first step to identify the need for palliative care and associated services. Aim: To analyse data from the Head and Neck 5000 study to present mortality, place and mode of death within 12 months of diagnosis. Design: Prospective cohort study. Participants: In total, 5402 people with a new diagnosis of head and neck cancer were recruited from 76 cancer centres in the United Kingdom between April 2011 and December 2014. Results: Initially, 161/5402 (3%) and 5241/5402 (97%) of participants were treated with ‘non-curative’ and ‘curative’ intent respectively. Within 12 months, 109/161 (68%) in the ‘non-curative’ group died compared with 482/5241 (9%) in the ‘curative’ group. Catastrophic bleed was the terminal event for 10.4% and 9.8% of people in ‘non-curative’ and ‘curative’ groups respectively; terminal airway obstruction was recorded for 7.5% and 6.3% of people in the same corresponding groups. Similar proportions of people in both groups died in a hospice (22.9% ‘non-curative’; 23.5% ‘curative’) and 45.7% of the ‘curative’ group died in hospital. Conclusions: In addition to those with incurable head and neck cancer, there is a small but significant ‘curative’ subgroup of people who may have palliative needs shortly following diagnosis. Given the high mortality, risk of acute catastrophic event and frequent hospital death, clarifying the level and timing of palliative care services engagement would help provide assurance as to whether palliative care needs are being met

Flux noise in high-temperature superconductors

Spontaneously created vortex-antivortex pairs are the predominant source of flux noise in high-temperature superconductors. In principle, flux noise measurements allow to check theoretical predictions for both the distribution of vortex-pair sizes and for the vortex diffusivity. In this paper the flux-noise power spectrum is calculated for the highly anisotropic high-temperature superconductor Bi-2212, both for bulk crystals and for ultra-thin films. The spectrum is basically given by the Fourier transform of the temporal magnetic-field correlation function. We start from a Berezinskii-Kosterlitz-Thouless type theory and incorporate vortex diffusion, intra-pair vortex interaction, and annihilation of pairs by means of a Fokker-Planck equation to determine the noise spectrum below and above the superconducting transition temperature. We find white noise at low frequencies omega and a spectrum proportional to 1/omega^(3/2) at high frequencies. The cross-over frequency between these regimes strongly depends on temperature. The results are compared with earlier results of computer simulations.Comment: 9 pages, 4 PostScript figures, to be published in Phys. Rev.

The palliative care needs and experiences of people with advanced head and neck cancer: a scoping review

Background: The palliative care needs of people with advanced head and neck cancer pose unique complexities due to the impact the illness has on eating, speaking, appearance and breathing. Examining these needs would help provide guidance about developing relevant models of care and identify gaps in research knowledge. Aim: To identify and map out the palliative care needs and experiences for people with advanced head and neck cancer. Design: A scoping literature review following the methods described by the Joanna Briggs Institute. Data sources: An electronic search of the literature was undertaken in MEDLINE (Ovid), EMBASE and CINAHL covering the years January 1996 to January 2019. Results: People with advanced head and neck cancer often had palliative care needs but there was variability in the timing and access to relevant services. A high prevalence of interventions, for example hospital admissions were needed even during the last month of life. This was not necessarily negated with early engagement of palliative care. Dissonance between patients and family carers about information needs and decision-making was an additional complexity. Studies tended to be descriptive in nature, and often involved a single centre. Conclusion: This scoping review demonstrates the complexity of care for people with advanced head and neck cancer and the issues related to the current healthcare systems. Focus on appropriate referral criteria, increased integration and coordination of care and robust evaluation of specific care components seems key. Linkage between research and service design delivery across teams, disciplines and care settings seems pertinent