Periodic magnetorotational dynamo action as a prototype of nonlinear magnetic field generation in shear flows

The nature of dynamo action in shear flows prone to magnetohydrodynamic instabilities is investigated using the magnetorotational dynamo in Keplerian shear flow as a prototype problem. Using direct numerical simulations and Newton's method, we compute an exact time-periodic magnetorotational dynamo solution to the three-dimensional dissipative incompressible magnetohydrodynamic equations with rotation and shear. We discuss the physical mechanism behind the cycle and show that it results from a combination of linear and nonlinear interactions between a large-scale axisymmetric toroidal magnetic field and non-axisymmetric perturbations amplified by the magnetorotational instability. We demonstrate that this large scale dynamo mechanism is overall intrinsically nonlinear and not reducible to the standard mean-field dynamo formalism. Our results therefore provide clear evidence for a generic nonlinear generation mechanism of time-dependent coherent large-scale magnetic fields in shear flows and call for new theoretical dynamo models. These findings may offer important clues to understand the transitional and statistical properties of subcritical magnetorotational turbulence.Comment: 10 pages, 6 figures, accepted for publication in Physical Review

The disorder parameter of dual superconductivity in QCD revisited

We discover the origin of the pathologies of the disorder parameter used in previous papers to detect dual superconductivity of QCD vacuum, and we remove them by defining an improved disorder parameter. A check of the approach is made by numerical simulations of SU(2) gauge theory, which demonstrate that the approach is consistent and with it that deconfinement is a transition from dual superconductor to normal.Comment: 13 pages, 12 eps figure

Estimation of social network user's influence in a given area of expertise

Nowadays social networks are frequently used to express personal opinion on a topic of interest. Some users' opinion has more informational influence than others do. These users are called influential users. There are services that allow evaluating how popular and influential users are; however, any information on evaluation methods is proprietary and represents know-how of such software services. Furthermore, most services could not provide extensive data on the influential users within the specified area of knowledge. This article proposes the method of evaluating a user influence index within a social network in a given area of expertise

Effects of Dietary Zn/Se and α-Tocopherol Supplementation on Metabolic Milieu, Haemogram and Semen Traits of Breeding Stallions

Trace element status and metabolic milieu are sometimes overlooked in common veterinary clinical practice across animal species. The evaluation of requirements of trace elements, in fact, may be useful to prevent the perturbation of tissue-specific metabolic impair. In particular, essential trace elements in the diet play key roles within sub-cellular metabolic patterns with macro effects at the systemic level, like blood cell stability and semen quality. This effect was studied in breeding stallions, in which semen quality and haemogram are important for reproduction. A case-control feeding trial involved 40 stallions (age: 8–21 years; body weight, BW: 510–531 kg) of one stud centre, allotted to two experimental groups (n = 20 control, CON vs. n = 20 supplemented, SUPPL100), following a matched-pairs approach based on age. Supplemented stallions (SUPPL100) received a mixed mineral and vitamin supplement of Zn/Se and α-tocopherol (α-TOH) (100 g/day stallion) to compound feed, fed as control diet to horses of the control group (CON). Horses resulted deficient in circulating α-TOH and Zn at the start, though clinically healthy. After supplementation, different plasmatic levels of α-TOH, Zn and Se were found between groups. Circulating basophils (BASO) and mean cell haemoglobin concentration (MCHC) were affected by the dietary treatment (p < 0.05). Plasmatic Se affected monocyte count, haematocrit, mean cell volume and mean cell haemoglobin concentration. Semen traits were not affected by the dietary treatment per se, except for mobile/progressive sperm cells (%) of stallions aged > 13 years marginal circulating levels of α-TOH (p = 0.04). Ameliorating the micromineral status showed to improve the haemogram of stallions in view of circulating levels of Cu. Semen quality appeared to be strongly dependent on animal effects

VGF peptide profiles in Type 2 diabetic patients' plasma and in obese mice

To address the possible involvement of VGF peptides in obesity and diabetes, we studied type 2 diabetes (T2D) and obese patients, and high-fat diet induced obese mice. Two VGF peptides (NAPP-19 and QQET-30) were identified in human plasma by HPLC-ESI-MS. The VGF C-terminus, the above two cleaved peptides, and the TLQP-21 related peptide/s were studied using ELISA and immunohistochemistry. In euglycemic patients, plasma NAPPE and TLQP like peptides were significantly reduced with obesity (74±10 vs. 167±28, and 92±10 vs. 191±19 pmol/ml, mean+SEM, n = 10 and 6, obese vs. normal BMI, respectively, p<0.03). Upon a standard glucose load, a distinct response was shown for VGF C-terminus, TLQP and QQET-like (ERVW immunoreactive) peptides in euglycemic normal BMI patients, but was virtually abolished in euglycemic obese, and in T2D patients independently of BMI. High-fat diet induced obese mice showed reduced plasma VGF C-terminus, NAPPE and QQET-like (ERVW) peptide/s (3±0.2 vs. 4.6±0.3, 22±3.5 vs. 34±1.3, and 48±7 vs. 100±7 pmol/ml, mean+SEM, n = 8/group, obese vs. slim, respectively, p<0.03), with a loss of the response to glucose for all VGF peptides studied. In immunohistochemistry, TLQP and/or VGF C-terminus antibodies labelled VGF containing perikarya in mouse celiac ganglia, pancreatic islet cells and thin beaded nerve fibres in brown adipose tissues, with fewer in white adipose tissue. Upon the glucose load, tyrosine hydroxylase and VGF C-terminus immunoreactive axons became apparent in pancreatic islets of slim animals, but not in obese animals. Alltogether, a significant loss of VGF peptide immunoreactivity and/or their response to glucose was demonstrated in obese patients, with or without T2D, in parallel with a similar loss in high-fat diet induced obese mice. An involvement of VGF in metabolic regulations, including those of brown and/or white adipose tissues is underlined, and may point out specific VGF peptides as potential targets for diagnosis and/or treatment

metronomic administration of pegylated liposomal doxorubicin in extensively pre treated metastatic breast cancer patients a mono institutional case series report

Abstract Background Metronomic chemotherapy has shown efficacy in patients with metastatic breast cancer. Pegylated liposomal-doxorubicin (PLD) pharmacokinetic characteristics support the rationale for using the drug in a metronomic fashion, potentially able to combine anthracyclines efficacy to a low toxicity profile. Patients and methods In a case-series report carried out in both anthracycline-naive and pre-treated metastatic breast cancer patients, we tested feasibility, clinical efficacy and tolerability of PLD administered with a novel metronomic schedule of 20 mg/m2 i.v. every two weeks. Results 52 patients were enrolled and 45 were evaluated. Forty-four patients were assessed for either response or toxicity. Eight patients (18%) had partial responses (PR) and 17 (39%) stable disease (SD), with a clinical benefit (CB) of 45% (95% CI: 30.3%–59.7%). Nineteen patients (43%) had progressive disease (PD). Neither grade 3 nor grade 4 haematological or clinical side effects were recorded, except for 2 patients with grade 3 palmar-plantar erythrodysesthesia (PPE). No cardiac toxicity was recorded. Conclusion Metronomic administration of PLD is a feasible and active treatment for extensively pre-treated metastatic breast cancer patients, alternative to classic anthracyclines, balancing clinical efficacy with a good quality of life in terms of reduced side effects and low personal costs for the patient