Interlaced particle systems and tilings of the Aztec diamond

Motivated by the problem of domino tilings of the Aztec diamond, a weighted particle system is defined on $N$ lines, with line $j$ containing $j$ particles. The particles are restricted to lattice points from 0 to $N$, and particles on successive lines are subject to an interlacing constraint. It is shown that marginal distributions for this particle system can be computed exactly. This in turn is used to give unified derivations of a number of fundamental properties of the tiling problem, for example the evaluation of the number of distinct configurations and the relation to the GUE minor process. An interlaced particle system associated with the domino tiling of a certain half Aztec diamond is similarly defined and analyzed.Comment: 17 pages, 4 figure

From interacting particle systems to random matrices

In this contribution we consider stochastic growth models in the Kardar-Parisi-Zhang universality class in 1+1 dimension. We discuss the large time distribution and processes and their dependence on the class on initial condition. This means that the scaling exponents do not uniquely determine the large time surface statistics, but one has to further divide into subclasses. Some of the fluctuation laws were first discovered in random matrix models. Moreover, the limit process for curved limit shape turned out to show up in a dynamical version of hermitian random matrices, but this analogy does not extend to the case of symmetric matrices. Therefore the connections between growth models and random matrices is only partial.Comment: 18 pages, 8 figures; Contribution to StatPhys24 special issue; minor corrections in scaling of section 2.

General practitioners' conceptions about treatment of depression and factors that may influence their practice in this area. A postal survey

BACKGROUND: The way GPs work does not appear to be adapted to the needs of depressive patients. Therefore we wanted to examine Swedish GPs' conceptions of depressive disorders and their treatment and GPs' ideas of factors that may influence their manner of work with depressive patients. METHODS: A postal questionnaire to a stratified sample of 617 Swedish GPs. RESULTS: Most respondents assumed antidepressive drugs effective and did not assume that psychotherapy can replace drugs in depression treatment though many of them looked at psychotherapy as an essential complement. Nearly all respondents thought that clinical experiences had great importance in decision situations, but patients' own preferences and official clinical guidelines were also regarded as essential. As influences on their work, almost all surveyed GPs regarded experiences from general practice very important, and a majority also emphasised experiences from private life. Courses arranged by pharmaceutical companies were seen as essential sources of knowledge. A majority thought that psychiatrists did not provide sufficient help, while most respondents perceived they were well backed up by colleagues. CONCLUSION: GPs tend to emphasize experiences, both from clinical work and private life, and overlook influences of collegial dealings and ongoing CME as well as the effects of the pharmaceutical companies' marketing activities. Many GPs appear to need more evidence based knowledge about depressive disorders. Interventions to improve depression management have to be supporting and interactive, and should be combined with organisational reforms to improve co-operation with psychiatrists

A systematic review of non-invasive modalities used to identify women with anal incontinence symptoms after childbirth

© 2018, The International Urogynecological Association. Introduction and hypothesis: Anal incontinence following childbirth is prevalent and has a significant impact upon quality of life (QoL). Currently, there is no standard assessment for women after childbirth to identify these symptoms. This systematic review aimed to identify non-invasive modalities used to identify women with anal incontinence following childbirth and assess response and reporting rates of anal incontinence for these modalities. Methods: Ovid Medline, Allied and Complementary Medicine Database (AMED), Cumulative Index of Nursing and Allied Health Literature (CINAHL), Cochrane Collaboration, EMBASE and Web of Science databases were searched for studies using non-invasive modalities published from January 1966 to May 2018 to identify women with anal incontinence following childbirth. Study data including type of modality, response rates and reported prevalence of anal incontinence were extracted and critically appraised. Results: One hundred and nine studies were included from 1602 screened articles. Three types of non-invasive modalities were identified: validated questionnaires/symptom scales (n = 36 studies using 15 different instruments), non-validated questionnaires (n = 50 studies) and patient interviews (n = 23 studies). Mean response rates were 92% up to 6 weeks after childbirth. Non-personalised assessment modalities (validated and non-validated questionnaires) were associated with reporting of higher rates of anal incontinence compared with patient interview at all periods of follow-up after childbirth, which was statistically significant between 6 weeks and 1 year after childbirth (p < 0.05). Conclusions: This systematic review confirms that questionnaires can be used effectively after childbirth to identify women with anal incontinence. Given the methodological limitations associated with non-validated questionnaires, assessing all women following childbirth for pelvic-floor symptomatology, including anal incontinence, using validated questionnaires should be considered

Sphincter-Sparing Anal Fistula Repair: Are We Getting Better?

BACKGROUND: Sphincter-sparing repairs are commonly used to treat anal fistulas with significant muscle involvement. OBJECTIVE: The current study evaluates the trends and efficacy of sphincter-sparing repairs and determines risk factors for fistula recurrence. DESIGN AND SETTINGS: A retrospective review was performed at 3 university-affiliated teaching hospitals. PATIENTS: All 462 patients with cryptoglandular anal fistulas who underwent 573 sphincter-sparing repairs between 2005 and 2015 were included. Patients with Crohn's disease were excluded. MAIN OUTCOME MEASURES: The primary outcome was the rate of fistula healing defined as cessation of drainage with closure of the external opening. Risk factors for nonhealing were also analyzed. RESULTS: Five hundred three sphincter-sparing repairs were analyzed, whereas 70 were lost to follow-up. Two hundred twenty sphincter-sparing repairs (44%) resulted in healing, 283 (56%) resulted in nonhealing with a median follow-up of 9 (range, 1-125) months. The median time to fistula recurrence was 3 (range, 0-75) months with 79% and 91% of recurrences noted within 6 and 12 months. Patients treated with a dermal advancement flap, rectal advancement flap, or ligation of the intersphincteric tract procedure were less likely to have a recurrence than patients treated with a fistula plug or fibrin glue (p < 0.001). Over time, there was a significantly increased use of the ligation of the intersphincteric tract procedure (p < 0.001) and a significantly decreased use of fistula plugs and fibrin glue (p < 0.001); healing rates improved accordingly. There were no significant differences in healing rates with respect to patient demographics, comorbidities, or fistula characteristics. LIMITATIONS: This study was limited by its retrospective design. CONCLUSIONS: Healing rates following sphincter-sparing repairs of cryptoglandular anal fistulas are modest, but have improved over time with the use of better surgical techniques. In this study, ligation of the intersphincteric fistula tract and flaps were superior to fistula plugs and fibrin glue; the former procedures are therefore favored. See Video Abstract at http://links.lww.com/DCR/A391