Overcoming the slowing down of flat-histogram Monte Carlo simulations: cluster updates and optimized broad-histogram ensembles

Journal ArticleWe study the performance of Monte Carlo simulations that sample a broad histogram in energy by determining the mean first-passage time to span the entire energy space of d-dimensional ferromagnetic Ising/Potts models. We first show that flat-histogram Monte Carlo methods with single-spin flip updates such as the Wang-Landau algorithm or the multicanonical method perform suboptimally in comparison to an unbiased Markovian random walk in energy space. For the d=1, 2, 3 Ising model, the mean first-passage time г scales with the number of spins N=Ld as г∞ N2Lz. The exponent z is found to decrease as the dimensionality d is increased. In the mean-field limit of infinite dimensions we find that z vanishes up to logarithmic corrections. We then demonstrate how the slowdown characterized by z>0 for finite d can be overcome by two complementary approaches-cluster dynamics in connection with Wang-Landau sampling and the recently developed ensemble optimization technique. Both approaches are found to improve the random walk in energy space so that г∞ N2 up to logarithmic corrections for the d=1, 2 Ising model

Artificial Intelligence in Requirements Engineering

thingsTHINKING versteht, verarbeitet und verwendet die Semantik der natürlichen Sprache und ist daher verwendbar für eine Vielzahl von Anwendungsfällen. Die bereits bestehende Software erkennt und löst Mängel in natürlicher Sprache von Anforderungsspezifikationen jeglicher Art. Einsatzmöglichkeiten bestehen im Industrie-4.0-Umfeld, bei Software-Herstellern und auch Beratungsunternehmen. Die semantische Verarbeitung natürlicher Sprache bietet viele weitere Möglichkeiten. Mit thingsTHINKING kann zum Beispiel der Kundendienst mit virtuellen Assistenten verbessert werden. Die LegalTech-Lösung könnte bei Entscheidungen und der Interpretation von Verträgen helfen oder einfach nur die Übersetzung für Nicht-Muttersprachler zu verbessern, indem zwischen Sinn und Ausdruck unterschieden wird. Die Anwendungsbereiche für diese Lösungen reichen von Banken, Telekommunikation bis zur Fertigung

Overcoming the critical slowing down of flat-histogram Monte Carlo simulations: Cluster updates and optimized broad-histogram ensembles

We study the performance of Monte Carlo simulations that sample a broad histogram in energy by determining the mean first-passage time to span the entire energy space of d-dimensional ferromagnetic Ising/Potts models. We first show that flat-histogram Monte Carlo methods with single-spin flip updates such as the Wang-Landau algorithm or the multicanonical method perform sub-optimally in comparison to an unbiased Markovian random walk in energy space. For the d=1,2,3 Ising model, the mean first-passage time \tau scales with the number of spins N=L^d as \tau \propto N^2L^z. The critical exponent z is found to decrease as the dimensionality d is increased. In the mean-field limit of infinite dimensions we find that z vanishes up to logarithmic corrections. We then demonstrate how the slowdown characterized by z>0 for finite d can be overcome by two complementary approaches - cluster dynamics in connection with Wang-Landau sampling and the recently developed ensemble optimization technique. Both approaches are found to improve the random walk in energy space so that \tau \propto N^2 up to logarithmic corrections for the d=1 and d=2 Ising model

Классификация удержаний из заработной платы

В данной научной статье поставлена задача, выяснить, как классифицируются удержания из заработной платы, отметить основные моменты для удержания. Также в статье рассматривается ситуация, когда один вид удержаний относится к разной классификации, на примере алиментов

Universality-class dependence of energy distributions in spin glasses

We study the probability distribution function of the ground-state energies of the disordered one-dimensional Ising spin chain with power-law interactions using a combination of parallel tempering Monte Carlo and branch, cut, and price algorithms. By tuning the exponent of the power-law interactions we are able to scan several universality classes. Our results suggest that mean-field models have a non-Gaussian limiting distribution of the ground-state energies, whereas non-mean-field models have a Gaussian limiting distribution. We compare the results of the disordered one-dimensional Ising chain to results for a disordered two-leg ladder, for which large system sizes can be studied, and find a qualitative agreement between the disordered one-dimensional Ising chain in the short-range universality class and the disordered two-leg ladder. We show that the mean and the standard deviation of the ground-state energy distributions scale with a power of the system size. In the mean-field universality class the skewness does not follow a power-law behavior and converges to a nonzero constant value. The data for the Sherrington-Kirkpatrick model seem to be acceptably well fitted by a modified Gumbel distribution. Finally, we discuss the distribution of the internal energy of the Sherrington-Kirkpatrick model at finite temperatures and show that it behaves similar to the ground-state energy of the system if the temperature is smaller than the critical temperature.Comment: 15 pages, 20 figures, 1 tabl

Shedding of Mycobacterium caprae by wild red deer (Cervus elaphus) in the Bavarian alpine regions, Germany

The number of natural infections with Mycobacterium caprae in wildlife and in cattle in the Bavarian and Austrian alpine regions has increased over the last decade. Red deer (Cervus elaphus) have been recognized as maintenance reservoir; however, the transmission routes of M. caprae among and from naturally infected red deer are unknown. The unexpected high prevalence in some hot spot regions might suggest an effective indirect transmission of infection. Therefore, this study was undertaken to diagnose the occurrence of M. caprae in faeces and secretions of red deer in their natural habitat. A total of 2,806 red deer hunted in this region during 2014–2016 were included in this study. After pathological examination, organs (lymph nodes, lung, heart), excretions and secretions (faeces, urine, saliva and tonsil swabs) were further investigated by qPCR specific for Mycobacterium tuberculosis complex (MTC), M. bovis and M. caprae. Samples tested positive by qPCR were processed for culturing of mycobacteria. In total, 55 (2.0%) animals were confirmed positive for M. caprae by pathological examination, PCR and culturing of the affected organ material. With the exception of one sample, all of the secretion and excretion samples were negative for mycobacteria of the Mycobacterium tuberculosis complex (MTC). From one red deer, M. caprae could be isolated from the heart sac as well as from the faeces. Whole‐genome sequencing confirmed that both strains were clonally related. This is the first confirmation that M. caprae can be shed with the faeces of a naturally infected red deer. However, further studies focusing on a higher number of infected animals, sample standardization and coordinated multiple sampling are necessary to improve the understanding of transmission routes under natural conditions

Expression of 3q Oncogene SEC62 Predicts Survival in Head and Neck Squamous Cell Carcinoma Patients Treated with Primary Chemoradiation

Primary chemoradiotherapy (CRT) is an established treatment option for locally advanced head and neck squamous cell carcinomas (HNSCC) usually combining intensity modified radiotherapy with concurrent platinum-based chemotherapy. Though the majority of patients can be cured with this regimen, treatment response is highly heterogeneous and can hardly be predicted. SEC62 represents a metastasis stimulating oncogene that is frequently overexpressed in various cancer entities and is associated with poor outcome. Its role in HNSCC patients undergoing CRT has not been investigated so far. A total of 127 HNSCC patients treated with primary CRT were included in this study. The median follow-up was 5.4 years. Pretherapeutic tissue samples of the primary tumors were used for immunohistochemistry targeting SEC62. SEC62 expression, clinical and histopathological parameters, as well as patient outcome, were correlated in univariate and multivariate survival analyses. High SEC62 expression correlated with a significantly shorter overall survival (p = 0.015) and advanced lymph node metastases (p = 0.024). Further significant predictors of poor overall and progression-free survival included response to therapy (RECIST1.1), nodal status, distant metastases, tobacco consumption, recurrence of disease, and UICC stage. In a multivariate Cox hazard proportional regression analysis, only SEC62 expression (p = 0.046) and response to therapy (p < 0.0001) maintained statistical significance as independent predictors of the patients’ overall survival. This study identified SEC62 as an independent prognostic biomarker in HNSCC patients treated with primary CRT. The role of SEC62 as a potential therapeutic target and its interaction with radiation-induced molecular alterations in head and neck cancer cells should further be investigated

Podoplanin expression in lymph node metastases of head and neck cancer and cancer of unknown primary patients

Introduction: Head and neck squamous cell carcinomas (HNSCCs) are cancers with generally poor prognosis. Outcomes have not improved in decades, with more than half of the patients presenting with lymph node metastases at the time of diagnosis. A unique subtype of HNSCC, cancer of unknown primary of the head and neck (HNCUP) is associated with a poor outcome. Increased expression of the D2-40 gene (podoplanin) has been described for several human malignancies and has been associated with increased metastatic potential of cancer cells. Methods: In order to examine the role of podoplanin in lymph node metastasis of HNSCC generally and HNCUP specifically, we evaluated the prognostic impact of podoplanin expression in HNSCC- (n=68) and HNCUP-associated lymph node metastases (n =30). The expression of podoplanin was analyzed by immunohistochemical staining of lymph node tissue samples and correlated with clinical and histopathological data. Results: We found a non-significant tendency towards a higher podoplanin expression in HNCUP compared to HNSCC lymph node metastases and a significant correlation between a high podoplanin expression and advanced node-stage classification. Podoplanin expression had no significant impact on overall survival for both groups and did not correlate with human papillomavirus tumor status. Conclusion: Taken together, our results suggest that upregulation of podoplanin may be associated with a stimulation of lymphatic metastasis in head and neck cancer

Cytology-based Cancer Surgery of the Head and Neck (CyCaS-HN): a prospective, randomized, controlled clinical trial

Purpose Liquid-based cytology (LBC) is routinely used in gynecology but is rarely applied in head and neck oncology though many suspicious lesions are easily accessible. While several studies have evaluated the potential use of LBC for early detection and molecular characterization of head and neck squamous cell carcinomas (HNSCCs), no study investigated its potential role in surgical management and therapy planning so far. Methods Twenty-fve patients with cT1-2 squamous cell carcinomas of the oral cavity and oropharynx were prospectively enrolled in this study and were randomized to two treatment arms: in the control arm, a diagnostic panendoscopy with incisional biopsy was followed by a second operation with transoral tumor resection±neck dissection and tracheostomy. In the intervention arm, patients underwent LBC diagnostics and in case of a positive result received one single operation with panendoscopy and incisional biopsy for confrmation of LBC result by rapid section histology followed by transoral tumor resection±neck dissection and tracheostomy in the same session. Results Time between clinical diagnosis and defnitive surgical treatment was signifcantly shorter in the intervention group compared with the control group (p<0.0001). Additionally, time of hospitalization (p<0.0001) and cumulative operation time (p=0.062) were shorter in the intervention group. No signifcant diferences in overall, progression-free, and diseasespecifc survival were observed. Conclusion Cytology-based cancer surgery is a promising therapeutic strategy that can potentially be considered for a well-defned group of early-stage HNSCC patients and help to avoid repetitive general anesthesia, shorten the diagnosis-totreatment interval and spare operation as well as hospitalization time