The m−m-dissimilarity map and representation theory of SLmSL_m

We give another proof that $m$-dissimilarity vectors of weighted trees are points on the tropical Grassmanian, as conjectured by Cools, and proved by Giraldo in response to a question of Sturmfels and Pachter. We accomplish this by relating $m$-dissimilarity vectors to the representation theory of $SL_m.$Comment: 11 pages, 8 figure

A matroid-friendly basis for the quasisymmetric functions

A new Z-basis for the space of quasisymmetric functions (QSym, for short) is presented. It is shown to have nonnegative structure constants, and several interesting properties relative to the space of quasisymmetric functions associated to matroids by the Hopf algebra morphism (F) of Billera, Jia, and Reiner. In particular, for loopless matroids, this basis reflects the grading by matroid rank, as well as by the size of the ground set. It is shown that the morphism F is injective on the set of rank two matroids, and that decomposability of the quasisymmetric function of a rank two matroid mirrors the decomposability of its base polytope. An affirmative answer is given to the Hilbert basis question raised by Billera, Jia, and Reiner.Comment: 25 pages; exposition tightened, typos corrected; to appear in the Journal of Combinatorial Theory, Series

Rehabilitation Program for Prosthetic Tracheojejunal Voice Production and Swallowing Function Following Circumferential Pharyngolaryngectomy and Neopharyngeal Reconstruction with a Jejunal Free Flap

The case of a 68-year-old woman with postoperative speech and swallowing problems following a circumferential pharyngolaryngectomy and neopharyngeal reconstruction with a jejunal free flap is presented. The primary tumor was an extended papillary thyroid carcinoma (pT4N0M0). For vocal restoration, an indwelling Provox® 1 voice prosthesis was inserted secondarily. The patient received speech and swallowing therapy, including digital maneuvers at the level of the proximal (cervical) part of the jejunal graft to improve speech and swallowing function. Pre- and/ or post-treatment data on speech and swallowing function were gathered using the following assessment methods: esophageal insufflation test, Voice Handicap Index (VHI), videofluoroscopy of phonation (VFSph), digital high-speed endoscopy of jejunal vibration during voice production, fiber-optic endoscopic evaluation of swallowing (FEES), and videofluoroscopy of swallowing (VFSs). This case clearly demonstrates that even after extensive laryngopharyngectomy with jejunal free flap reconstruction, a tailored rehabilitation program can improve both voice and swallowing function, and that these results clearly can be objectified/visualized, underlining the validity of this approach

Swallowing in Parkinson Patients versus Healthy Controls: Reliability of Measurements in Videofluoroscopy

Objective. To determine and describe the pathophysiological aspects of oropharyngeal swallowing in patients with Parkinson's disease more accurately, a pilot study of qualitative as well as quantitative parameters of swallowing was performed using videofluoroscopy (VFS). Methods. Ten patients with a diagnosis of idiopathic Parkinson's disease having dysphagic complaints and ten healthy age- and gender-matched control subjects underwent a standardized videofluoroscopic swallowing protocol. Information on the swallowing function was derived from temporal, spatial, and descriptive visuoperceptual parameters. Intra- and interrater reliability was calculated. Results. No significant differences were found between Parkinson patients and healthy control subjects for the majority of the reliable variables. Conclusions. It was concluded that swallowing function seemed to be preserved in the early stages of Parkinson's disease. Furthermore, the reliability of many quantitative as well as qualitative swallowing parameters proved insufficient, raising questions about the interpretation of study outcomes in videofluoroscopy

White Paper by the European Society for Swallowing Disorders: screening and non-instrumental assessment for dysphagia in adults

This White Paper by the European Society for Swallowing Disorders (ESSD) reports on the current state of screening and non-instrumental assessment for dysphagia in adults. An overview is provided on the measures that are available, and how to select screening tools and assessments. Emphasis is placed on different types of screening, patient-reported measures, assessment of anatomy and physiology of the swallowing act, and clinical swallowing evaluation. Many screening and non-instrumental assessments are available for evaluating dysphagia in adults; however, their use may not be warranted due to poor diagnostic performance or lacking robust psychometric properties. This white paper provides recommendations on how to select best evidence-based screening tools and non-instrumental assessments for use in clinical practice targeting different constructs, target populations and respondents, based on criteria for diagnostic performance, psychometric properties (reliability, validity, and responsiveness), and feasibility. In addition, gaps in research that need to be addressed in future studies are discussed. The following recommendations are made: (1) discontinue the use of non-validated dysphagia screening tools and assessments; (2) implement screening using tools that have optimal diagnostic performance in selected populations that are at risk of dysphagia, such as stroke patients, frail older persons, patients with progressive neurological diseases, persons with cerebral palsy, and patients with head and neck cancer; (3) implement measures that demonstrate robust psychometric properties; and (4) provide quality training in dysphagia screening and assessment to all clinicians involved in the care and management of persons with dysphagia.Otorhinolaryngolog

Computing the vertices of tropical polyhedra using directed hypergraphs

We establish a characterization of the vertices of a tropical polyhedron defined as the intersection of finitely many half-spaces. We show that a point is a vertex if, and only if, a directed hypergraph, constructed from the subdifferentials of the active constraints at this point, admits a unique strongly connected component that is maximal with respect to the reachability relation (all the other strongly connected components have access to it). This property can be checked in almost linear-time. This allows us to develop a tropical analogue of the classical double description method, which computes a minimal internal representation (in terms of vertices) of a polyhedron defined externally (by half-spaces or hyperplanes). We provide theoretical worst case complexity bounds and report extensive experimental tests performed using the library TPLib, showing that this method outperforms the other existing approaches.Comment: 29 pages (A4), 10 figures, 1 table; v2: Improved algorithm in section 5 (using directed hypergraphs), detailed appendix; v3: major revision of the article (adding tropical hyperplanes, alternative method by arrangements, etc); v4: minor revisio

Factors influencing the outcome of intrauterine insemination (IUI): age, clinical variables and significant thresholds

The aim was to investigate the influence of various biological factors upon the outcome of intrauterine insemination (IUI). The total IUI history (856 cycles) of 352 couples was studied. Live-birth showed a strong negative correlation with female age but no correlation with male age. Antimullerian hormone (AMH) and antral follicle count (AFC) correlated negatively with female age, and follicle stimulating hormone (FSH) correlated positively. Significant thresholds were found for all three variables, and also for total motile count (TMC) in the prepared sperm. Calculating pregnancy losses per positive pregnancy showed a strong correlation with increasing female age. This was highly significant for biochemical losses but not for fetal heart miscarriages. Male age had no effect on rate of pregnancy loss. In conclusion, female age, FSH, AMH and TMC are good predictive factors for live-birth and therefore relate to essential in vivo steps in the reproductive process

Quality of Life in Oncological Patients with Oropharyngeal Dysphagia: Validity and Reliability of the Dutch Version of the MD Anderson Dysphagia Inventory and the Deglutition Handicap Index

Quality of life is an important outcome measurement in objectifying the current health status or therapy effects in patients with oropharyngeal dysphagia. In this study, the validity and reliability of the Dutch version of the Deglutition Handicap Index (DHI) and the MD Anderson Dysphagia Inventory (MDADI) have been determined for oncological patients with oropharyngeal dysphagia. At Maastricht University Medical Center, 76 consecutive patients were selected and asked to fill in three questionnaires on quality of life related to oropharyngeal dysphagia (the SWAL-QOL, the MDADI, and the DHI) as well as a simple one-item visual analog Dysphagia Severity Scale. None of the quality-of-life questionnaires showed any floor or ceiling effect. The test-retest reliability of the MDADI and the Dysphagia Severity Scale proved to be good. The test-retest reliability of the DHI could not be determined because of insufficient data, but the intraclass correlation coefficients were rather high. The internal consistency proved to be good. However, confirmatory factor analysis could not distinguish the underlying constructs as defined by the subscales per questionnaire. When assessing criterion validity, both the MDADI and the DHI showed satisfactory associations with the SWAL-QOL (reference or gold standard) after having removed the less relevant subscales of the SWAL-QOL. In conclusion, when assessing the validity and reliability of the Dutch version of the DHI or the MDADI, not all psychometric properties have been adequately met. In general, because of difficulties in the interpretation of study results when using questionnaires lacking sufficient psychometric quality, it is recommended that researchers strive to use questionnaires with the most optimal psychometric properties

In assisted reproduction by IVF or ICSI, the rate at which embryos develop to the blastocyst stage is influenced by the fertilization method used: a split IVF/ICSI study

PURPOSE: To compare in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI) in regard to post-fertilization development and outcome with the purpose of ascertaining the most effective fertilization method for assisted reproduction. METHODS: A retrospective cohort study of 136 split IVF/ICSI cycles (where sibling oocytes are fertilized by two different methods using the same sperm sample). RESULTS: IVF-derived embryos developed to the blastocyst stage at a significantly faster rate than ICSI-derived embryos. There was no significant difference in fertilization or livebirth rates between the two fertilization methods. CONCLUSIONS: For patients with sperm progressive motility ≥ 1.0 × 106/ml (who usually constitute the majority of patients), no significant difference between the two fertilization methods was found in regard to fertilization rate or livebirth rate. Remaining factors influencing choice between the two methods appear to be restricted to convenience, financial considerations and concern with regard to possible perpetuation of genetically linked infertility to future generations

Integrable structure of box-ball systems: crystal, Bethe ansatz, ultradiscretization and tropical geometry

The box-ball system is an integrable cellular automaton on one dimensional lattice. It arises from either quantum or classical integrable systems by the procedures called crystallization and ultradiscretization, respectively. The double origin of the integrability has endowed the box-ball system with a variety of aspects related to Yang-Baxter integrable models in statistical mechanics, crystal base theory in quantum groups, combinatorial Bethe ansatz, geometric crystals, classical theory of solitons, tau functions, inverse scattering method, action-angle variables and invariant tori in completely integrable systems, spectral curves, tropical geometry and so forth. In this review article, we demonstrate these integrable structures of the box-ball system and its generalizations based on the developments in the last two decades.Comment: 73 page