Three-points interfacial quadrature for geometrical source terms on nonuniform grids

International audienceThis paper deals with numerical (finite volume) approximations, on nonuniform meshes, for ordinary differential equations with parameter-dependent fields. Appropriate discretizations are constructed over the space of parameters, in order to guarantee the consistency in presence of variable cells' size, for which $L^p$-error estimates, $1\le p < +\infty$, are proven. Besides, a suitable notion of (weak) regularity for nonuniform meshes is introduced in the most general case, to compensate possibly reduced consistency conditions, and the optimality of the convergence rates with respect to the regularity assumptions on the problem's data is precisely discussed. This analysis attempts to provide a basic theoretical framework for the numerical simulation on unstructured grids (also generated by adaptive algorithms) of a wide class of mathematical models for real systems (geophysical flows, biological and chemical processes, population dynamics)

Transport theories for heavy ion collisions in the 1 AGeV regime

We compare multiplicities as well as rapidity and transverse momentum distributions of protons, pions and kaons calculated within presently available transport approaches for heavy ion collisions around 1 AGeV. For this purpose, three reactions have been selected: Au+Au at 1 and 1.48 AGeV and Ni+Ni at 1.93 AGeV

Electropalatographic assessment of tongue-to-palate contacts exhibited in dysarthria following traumatic brain injury: Spatial characteristics

Consonant imprecision has been reported to be a common feature of the dysarthric speech disturbances exhibited by individuals who have sustained a traumatic brain injury (TBI). Inaccurate tongue placements against the hard palate during consonant articulation may be one factor underlying the imprecision. To investigate this hypothesis, electropalatography (EPG) was used to assess the spatial characteristics of the tongue-to-palate contacts exhibited by three males (aged 23-29 years) with dysarthria following severe TBI. Five nonneurologically impaired adults served as control subjects. Twelve single-syllable words of CV or CVC construction (where initial C = /t, d, S, z, k, g/, V=/i, a/) were read aloud three times by each subject while wearing an EPG palate. Spatial characteristics were analyzed in terms of the location, pattern, and amount of tongue-to-palate contact at the frame of maximum contact during production of each consonant. The results revealed that for the majority of consonants, the patterns and locations of contacts exhibited by the TBI subjects were consistent with the contacts generated by the group of control subjects. One notable exception was one subject's production of the alveolar fricatives in which complete closure across the palate was demonstrated, rather than the characteristic groove configuration. Major discrepancies were also noted in relation to the amount of tongue-to-palate contact exhibited, with two TBI subjects consistently demonstrating increased contacts compared to the control subjects. The implications of these findings for the development of treatment programs for dysarthric speech disorders subsequent to TBI are highlighted

Yang Baxter maps with first degree polynomial 2 by 2 Lax matrices

A family of nonparametric Yang Baxter (YB) maps is constructed by refactorization of the product of two 2 by 2 matrix polynomials of first degree. These maps are Poisson with respect to the Sklyanin bracket. For each Casimir function a parametric Poisson YB map is generated by reduction on the corresponding level set. By considering a complete set of Casimir functions symplectic multiparametric YB maps are derived. These maps are quadrirational with explicit formulae in terms of matrix operations. Their Lax matrices are, by construction, 2 by 2 first degree polynomial in the spectral parameter and are classified by Jordan normal form of the leading term. Nonquadrirational parametric YB maps constructed as limits of the quadrirational ones are connected to known integrable systems on quad graphs

Prevention of wound complications following salvage laryngectomy using free vascularized tissue

Background. Total laryngectomy following radiation therapy or concurrent chemoradiation therapy is associated with unacceptably high complication rates because of wound healing difficulties. With an ever increasing reliance on organ preservation protocols as primary treatment for advanced laryngeal cancer, the surgeon must develop techniques to minimize postoperative complications in salvage laryngectomy surgery. We have developed an approach using free tissue transfer in an effort to improve tissue vascularity, reinforce the pharyngeal suture line, and minimize complications in this difficult patient population. The purpose of this study was to outline our technique and determine the effectiveness of this new approach. Methods. We conducted a retrospective review of a prospective cohort and compared it with a historical group (surgical patients of Radiation Therapy Oncology Group (RTOG)-91-11 trial). Eligibility criteria for this study included patients undergoing salvage total laryngectomy following failed attempts at organ preservation with either high-dose radiotherapy or concurrent chemo/radiation therapy regimen. Patients were excluded if the surgical defect required a skin paddle for pharyngeal closure. The prospective cohort consisted of 14 consecutive patients (10 males, 4 females; mean age, 58 years) who underwent free tissue reinforcement of the pharyngeal suture line following total laryngectomy. The historical comparison group consisted of 27 patients in the concomitant chemoradiotherapy arm of the RTOG-91-11 trial who met the same eligibility criteria (26 males, 1 female; mean age, 57 years) but did not undergo free tissue transfer or other form of suture line reinforcement. Minimum follow-up in both groups was 12 months. Results. The overall pharyngocutaneous fistula rate was similar between groups—4/14 (29%) in the flap group, compared with 8/27 (30%) in the RTOG-91-11 group. There were no major wound complications in the flap group, compared with 4 (4/27, 14.8%) in the RTOG-91-11 group. There were no major fistulas in the flap group, compared with 3/27 (11.1%) in the RTOG-91-11 group. The rate of pharyngeal stricture requiring dilation was 6/14 (42%) in the flap group, compared with 7/27 (25.9%) in the RTOG-91-11 group. In our patients, the rate of tracheoesophageal speech was 14/14 (100%), and complete oral intake was achieved in 13/14 (93%) patients. Voice-Related Quality of Life Measure (V-RQOL) and Performance Status Scale for Head and Neck Cancer Patients (PSS-HN) scores suggest that speech and swallowing functions are reasonable following free flap reinforcement. Conclusions. Free vascularized tissue reinforcement of primary pharyngeal closure in salvage laryngectomy following failed organ preservation is effective in preventing major wound complications but did not reduce the overall fistula rate. Fistulas that developed following this technique were relatively small, did not result in exposed major vessels, and were effectively treated with outpatient wound care rather than readmission to the hospital or return to operating room. Speech and swallowing results following this technique were comparable to those following total laryngectomy alone. © 2007 Wiley Periodicals, Inc. Head Neck 2007Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56020/1/20492_ftp.pd

Assessing dysphagia via telerehabilitation: patient perceptions and satisfaction

To gain insight into factors which may infl uence future acceptance of dysphagia management via telerehabilitation, patients’ perceptions were examined before and after a telerehabilitation assessment session. Forty adult patients with dysphagia(M = 66 years, SD = 16.25) completed pre- and post-session questionnaires which consisted of 14 matched questions worded to suit pre- and post-conditions. Questions explored comfort with the use of telerehabilitation, satisfaction with audio and video quality, benefi ts of telerehabilitation assessments and patients’ preferred assessment modality. Questions were rated on a 5-point scale (1 = strongly disagree, 3 = unsure, 5 = strongly agree). Patients’ comfort with assessment via telerehabilitation was high in over 80% of the group both pre- and post-assessment. Pre-assessment, patients were unsure what to expect with the auditory and visual aspects of the videoconference, however there were signifi cant positive changes reported post-experience. In relation to perceived benefits of telerehabilitation services in general, most patients believed in the value of telerehabilitation and post-assessment this increased to 90 – 100% agreement. Although 92% felt they would be comfortable receiving services via telerehabilitation, 45% of patients indicated ultimate preference for a traditional faceto-face assessment. The data highlight that patients are interested in and willing to receive services via telerehabilitation; however, any concerns should be addressed pre-assessment