Random Sampling in Computational Algebra: Helly Numbers and Violator Spaces

This paper transfers a randomized algorithm, originally used in geometric optimization, to computational problems in commutative algebra. We show that Clarkson's sampling algorithm can be applied to two problems in computational algebra: solving large-scale polynomial systems and finding small generating sets of graded ideals. The cornerstone of our work is showing that the theory of violator spaces of G\"artner et al.\ applies to polynomial ideal problems. To show this, one utilizes a Helly-type result for algebraic varieties. The resulting algorithms have expected runtime linear in the number of input polynomials, making the ideas interesting for handling systems with very large numbers of polynomials, but whose rank in the vector space of polynomials is small (e.g., when the number of variables and degree is constant).Comment: Minor edits, added two references; results unchange

Gr\"obner Bases and Nullstellens\"atze for Graph-Coloring Ideals

We revisit a well-known family of polynomial ideals encoding the problem of graph-$k$-colorability. Our paper describes how the inherent combinatorial structure of the ideals implies several interesting algebraic properties. Specifically, we provide lower bounds on the difficulty of computing Gr\"obner bases and Nullstellensatz certificates for the coloring ideals of general graphs. For chordal graphs, however, we explicitly describe a Gr\"obner basis for the coloring ideal, and provide a polynomial-time algorithm.Comment: 16 page

CHB Converter DC Voltage Control Based on Feedback Linearization

In this paper the Feedback Linearization (FL) control theory is applied to a grid-connected Cascaded H-Bridge (CHB) converter. A DC voltage control is designed taking into account the nonlinear model of the converter and its performances are compared with the performances obtained in case of a conventional PI controller. With the aim to provide a fair comparison, the results are evaluated in terms of: settling time in case of a reference voltage variation, voltage overshoot in case of a load variation and total harmonic distortion of the grid current. Simulation and experimental results demonstrate that the FL-based control provides higher power quality and faster response to reference variations than the PI control. Comparing the performances in terms of responses to the load variations, better dynamics performance can be achieved also with the FL-based control increasing the settling time while maintaining an admissible grid current total harmonic distortion index

β models for random hypergraphs with a given degree sequence

We introduce the beta model for random hypergraphs in order to represent the occurrence of multi-way interactions among agents in a social network. This model builds upon and generalizes the well-studied beta model for random graphs, which instead only considers pairwise interactions. We provide two algorithms for fitting the model parameters, IPS (iterative proportional scaling) and fixed point algorithm, prove that both algorithms converge if maximum likelihood estimator (MLE) exists, and provide algorithmic and geometric ways of dealing the issue of MLE existence

Pelvic floor muscle behavior during Valsalva leak point pressure measurement in males and females affected by stress urinary incontinence.

PURPOSE: We evaluated pelvic floor muscle (PFM) behavior during Valsalva leak point pressure (VLPP) measurement in males and females affected by stress urinary incontinence and investigated whether VLPP results are influenced by PFM contraction. MATERIALS AND METHODS: A total of 25 females and 14 males underwent surface electromyographic (EMG) recording of PFM activity while performing VLPP. We investigated 2 conditions, VLPP during spontaneous strain (test A), and with simultaneous relaxation of the pelvic floor (test B). We analyzed average EMG activity (microV) at rest and during VLPP in tests A and B, the increasing EMG activity during tests A and B (the difference between average EMG activity during tests A and B and at rest), and the mean duration (seconds) of EMG activity during tests A and B. RESULTS: We detected a significant increase in EMG activity during tests A and B as compared to activity at rest (p <0.0001). Increasing EMG activity during test B was significantly reduced in females (p <0.05) but not in males. During test A patients reporting urinary incontinence showed a significantly lower EMG activity than that of continent patients (p <0.05). A significant reduction in maximum abdominal pressure was detected in test B compared to test A, but there was no difference in VLPP values between tests A and B. CONCLUSIONS: PFM activity significantly increases during VLPP measurement. Eliminating muscular contraction of the pelvic floor does not significantly alter VLPP results

Histomorphometrical Evaluation of Myocyte Types in the Lamb

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The efficacy and safety of duloxetine in a multidrug regimen for chronic prostatitis/chronic pelvic pain syndrome.

OBJECTIVE To evaluate the efficacy and safety of duloxetine hydrochloride in the treatment of patients affected by chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). METHODS Thirty-eight CP/CPPS patients completed the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) and International Index of Erectile Function-Erectile Function-5 (IIEF-5) questionnaires, uroflowmetry, and evaluation of psychologic status using Hamilton Anxiety Scale (HAM-A) and Hamilton Depression Scale (HAM-D). Patients were randomly assigned to 2 treatments groups. Treatment in group 1 consisted of a simultaneous oral administration of tamsulosin (0.4 mg/d, 60 mg/d), saw palmetto (320 mg/d), and duloxetine (60 mg/d). Treatment in group 2 consisted of tamsulosin (0.4 mg/d) and saw palmetto (320 mg/d). NIH-CPSI and IIEF-5 questionnaires, uroflowmetry, and evaluation of the psychological status were repeated at 16 weeks of follow-up. RESULTS At 16 weeks, a significant improvement in NIH-CPSI pain subscore, NIH-CPSI quality of life subscore, and NIH-CPSI total score were observed in group 1 patients compared with those in group 2 (P <.01, respectively), together with a significant improvement in HAM-A and HAM-D scores (P <.01, respectively). Patients in group 2 showed a significant improvement in NIH-CPSI total score, in the urinary symptoms subscore, and in the HAM-A total score. No significant differences were observed in IIEF-5 scores in the 2 groups. Maximum flow rate significantly increased in both groups. In group 1, 20% of patients stopped the study due to adverse effects. CONCLUSION The use of duloxetine in a multimodal treatment with an alpha-blocker medication and a saw palmetto extract allowed better results in controlling clinical symptoms, psychologic status and quality of life patients affected by CP/CPPS

Integration of 3G connectivity in planetlab Europe :A step of an evolutionary path towards heterogeneous large scale network testbeds

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VARIATION IN MEAT QUALITY CHARACTERISTICS BETWEEN LANDRACE AND SICILIAN PIGS

This study compared the meat quality of Sicilian and Landrace pigs breeds and supported these results with biochemical and histological measurements on the samples collected from the m. Longissimus Dorsi, at the level of the 8th thoracic vertebra, before electrical stimulation. Twenty clinically healthy swine, 10 male (5 for each pig breed) and 10 female (5 for each pig breed), were slaughtered at 1 year of age at a body mass of 135±10 kg and 150±10 respectively for Sicilian and Landrace pigs. Particularly on the muscle considered the morphometric characteristics of FG (fast glycolytic), FOG (fast oxidative glycolytic) and SO (slow oxidative) fibre types and their percentage were determined. Measurements related to myofibrillar fragmentation, sarcomere length and connective tissue properties gave convincing support. Sicilian pig produced more tender meat than Landrace, mainly due to favourable calpain-to-calpastatin ratios

Idiopathic thrombocytopenic purpura: current concepts in pathophysiology and management.

Idiopathic thrombocytopenic purpura (ITP) is characterized by a low platelet count, which is the result of both increased pla- telet destruction and insufficient platelet production. Although the development of autoantibodies against platelet glycoproteins remains central in the pathophysiology of ITP, several abnormalities involving the cellular mechanisms of immune modu- lation have been identified. Conventional treatments for ITP aim at reducing platelet destruction, either by immunosuppression or splenectomy. Two new thrombopoietic agents,AMG 531 and eltrombopag, have been used in clinical trials to stimulate platelet production in ITP patients not responsive to standard treatments. These new molecules bear no structural resemblance to thrombopoietin, but still bind and activate the thrombopoietin receptor. This review will focus on the pathophysiology and treatment of ITP in adults, highlighting recent advances in both fields