A trust model for spreading gossip in social networks

We introduce here a multi-type bootstrap percolation model, which we call T-Bootstrap Percolation (T-BP), and apply it to study information propagation in social networks. In this model, a social network is represented by a graph G whose vertices have different labels corresponding to the type of role the person plays in the network (e.g. a student, an educator, etc.). Once an initial set of vertices of G is randomly selected to be carrying a gossip (e.g. to be infected), the gossip propagates to a new vertex provided it is transmitted by a minimum threshold of vertices with different labels. By considering random graphs, which have been shown to closely represent social networks, we study different properties of the T-BP model through numerical simulations, and describe its implications when applied to rumour spread, fake news, and marketing strategies.Comment: 9 pages, 9 figure

Asymptotic normality of quadratic forms of martingale differences

We establish the asymptotic normality of a quadratic form QnQn in martingale difference random variables ηtηt when the weight matrix A of the quadratic form has an asymptotically vanishing diagonal. Such a result has numerous potential applications in time series analysis. While for i.i.d. random variables ηtηt, asymptotic normality holds under condition ||A||sp=o(||A||)||A||sp=o(||A||), where ||A||sp||A||sp and ||A|| are the spectral and Euclidean norms of the matrix A, respectively, finding corresponding sufficient conditions in the case of martingale differences ηtηt has been an important open problem. We provide such sufficient conditions in this paper

Comparative study of patient-based versus case-based teaching in prescription writing skills of second year MBBS students

Background: Prescription writing errors can lead to deficiencies in healthcare. Although prescription writing is a part of the medical students' curriculum with traditional methods, their prescribing skills are still poor due to inadequate training. To fulfil the need for new educational interventions this study aims to compare patient-based teaching with case-based teaching in improving prescription writing skills of second year MBBS students.Methods: This prospective comparative study was carried out after orientation of participants to prescription writing as per WHO prescribing guidelines (n=71). Group A (n=37) and group B (n=34) were given patient-based teaching and case-based teaching respectively of prescription writing for the same five common clinical conditions. The prescription writing skill was assessed by evaluating the prescriptions written by both the groups and scored by 19-point scoring system. Feedback from the group A students was also taken.Results: Statistical analysis of mean scores of group A (15.90) and group B (13.14) was done by Mann-Whitney U test (p<0.001). Comparison of both the groups for the individual parameters was done by Chi-square test which found significant difference in writing some important parameters like doctor’s registration no., contacts of prescriber, name of the medicine, strength of drug, dosage form, dosing instructions, total quantity of medicine and duration of medication etc. Group A students’ feedback brought out the fact that patient-based teaching is a good tool for teaching and learning.Conclusions: Patient-based teaching for prescription writing improves students’ prescription writing skills in an effective way in comparison with traditional case-based teaching

Magnetic Properties of Ni-Fe Nanowire Arrays: Effect of Template Material and Deposition Conditions

The objective of this work is to study the magnetic properties of arrays of Ni-Fe nanowires electrodeposited in different template materials such as porous silicon, polycarbonate and alumina. Magnetic properties were studied as a function of template material, applied magnetic field (parallel and perpendicular) during deposition, wire length, as well as magnetic field orientation during measurement. The results show that application of magnetic field during deposition strongly influences the c-axis preferred orientation growth of Ni-Fe nanowires. The samples with magnetic field perpendicular to template plane during deposition exhibits strong perpendicular anisotropy with greatly enhanced coercivity and squareness ratio, particularly in Ni-Fe nanowires deposited in polycarbonate templates. In case of polycarbonate template, as magnetic field during deposition increases, both coercivity and squareness ratio also increase. The wire length dependence was also measured for polycarbonate templates. As wire length increases, coercivity and squareness ratio decrease, but saturation field increases. Such magnetic behavior (dependence on template material, magnetic field, wire length) can be qualitatively explained by preferential growth phenomena, dipolar interactioComment: 26 pages, 7 figures, 5 Tables Submitted to Physical Review

Assessment of efficacy and safety of artesunate plus sulfadoxine pyrimethamine combination for treatment of uncomplicated falciparum malaria

Background: Resistance of Plasmodium falciparum to antimalarial drugs is common in India. World Health Organization (WHO) recommends artemisinin‑based combination therapy (ACT) to counter the development of resistance in P. falciparum. WHO recommends that ideally antimalarial drug treatment policy or guidelines should be reviewed regularly and updated at least once every 24 months. In consideration to the above recommendation, we planned to conduct the following study. The objective was to determine the efficacy and safety of artesunate + sulphadoxine‑pyrimethamine (AS + SP) in patients with uncomplicated P. falciparum malaria.Methods: The study included 60 patients of uncomplicated P. falciparum. Each patient received AS + SP as per WHO guidelines. Diagnosis was confirmed by peripheral blood film. All patients were followed‑up on days 1, 3, 14, and 28 for detailed clinical and parasitological examination.Results: Of a total 60 patients, 55 patients were followed‑up for 28 days. Remaining 5 patients were lost in follow‑up. As per protocol analysis, 91% (50) of patients had demonstrated adequate clinical and parasitological response. Remaining 9% (5) had treatment failure in which 5.5% (3) had late parasitological failure and 3.6% (2) had late clinical failure. In our study, mean parasite clearance time was 45.2 ± 4.2 hrs.Conclusion: AS + SP is safe and effective drug for the treatment of uncomplicated falciparum malaria. However, the efficacy of this ACT needs to be carefully monitored periodically since treatment failure can occur due to resistance

Long memory conditional random fields on regular lattices

This paper draws its motivation from applications in geophysics, agricultural, and environmental sciences where empirical evidence of slow decay of correlations have been found for data observed on a regular lattice. Spatial ARFIMA models represent a widely used class of spatial models for analyzing such data. Here, we consider their generalization to conditional autoregressive fractional integrated moving average (CARFIMA) models, a larger class of long memory models which allows a wider range of correlation behavior. For this class we provide detailed descriptions of important representative models, make the necessary comparison with some other existing models, and discuss some important inferential and computational issues on estimation, simulation and long memory process approximation. Results from model fit comparison and predictive performance of CARFIMA models are also discussed through a statistical analysis of satellite land surface temperature data

Randomized double-blind study comparing the efficacy and safety of lamotrigine and amitriptyline in painful diabetic neuropathy

WSTĘP. Celem niniejszej pracy było porównanie skuteczności oraz bezpieczeństwa stosowania lamotryginy i amitryptyliny w opanowywaniu przewlekłego bólu spowodowanego obwodową neuropatią u chorych na cukrzycę. MATERIAŁ I METODY. Badanie kliniczne z randomizacją przeprowadzono w układzie naprzemiennym metodą podwójnie ślepej próby, z grupą kontrolną otrzymującą terapię standardową. W badaniu wzięły udział 53 osoby. Zastosowano różne dawki leków. Amitryptylinę stosowano w 3 dawkach doustnie: 10, 25 lub 50 mg, jednorazowo na noc przez 2 tygodnie, a lamotryginę - doustnie, 2 × na dobę, w 3 dawkach: 25, 50 lub 100 mg; każdą z dawek stosowano przez 2 tygodnie. Między zamianą leków zastosowano 2-tygodniową przerwę, podczas której chorzy otrzymywali placebo. Oceniano wpływ terapii na zmniejszenie bólu, ogólne polepszenie stanu zdrowia oraz wystąpienie działań niepożądanych. WYNIKI. W ogólnej ocenie pacjentów zniesienie bólu w dużym, umiarkowanym i małym stopniu zanotowano odpowiednio u 19 (41%), 6 (13%) i 7 (15%) osób przyjmujących lamotryginę oraz u 13 (28%), 5 (11%) i 15 (33%) osób stosujących amitryptylinę. Ogólna ocena przeprowadzona przez pacjentów i lekarzy, kwestionariusz McGilla i skala bólu Likerta nie wykazały różnic istotnych statystycznie. Poprawę obserwowano już po 2 tygodniach stosowania obu leków. Odnotowano 44 przypadki działań niepożądanych, 33 (75%) dotyczyły amitryptyliny, z czego najczęściej stwierdzano działanie nasenne (19 pacjentów, 43%); 11 przypadków (25%) dotyczyło lamotryginy, najczęściej była to wysypka (3 chorych, 7%) i podwyższenie stężenia kreatyniny (4 osoby, 9%). Preferowana dawka lamotryginy to 25 mg 2 × na dobę. WNIOSKI. Mimo że wykazano niewiele różnic w skuteczności obu leków, wybór lamotryginy w dawce 25 mg 2 × na dobę wydaje się lepszy, ze względu na mniejszą liczbę działań niepożądanych wywołanych w badanej populacji.AIMS. To compare the efficacy and safety of lamotrigine and amitriptyline in controlling chronic painful peripheral neuropathy in diabetic patients. METHODS. A randomized, double-blind, crossover, active-control, clinical trial with variable dose titration was carried out (n = 53). Amitriptyline orally, at doses of 10, 25 and 50 mg at night-time, each dose for 2 weeks, and lamotrigine orally, at doses of 25, 50 and 100 mg twice daily, each dose for 2 weeks, by optional titration were used. There was a placebo washout period for 2 weeks between the two drugs. Assessment for pain relief, overall improvement and adverse events were carried out. RESULTS. Good, moderate and mild pain relief were noted in 19 (41%), six (13%) and seven (15%) patients on lamotrigine and 13 (28%), five (11%) and 15 (33%) patients on amitriptyline, respectively, by patient&#8217;s global assessment of efficacy and safety. Patient and physicians global assessment, McGill pain questionnaire and Likert pain scale showed no significant difference between the treatments, although improvement with both treatments was seen from 2 weeks. Of the 44 adverse events reported, 33 (75%) were with amitriptyline, sedation being the commonest [in 19 (43%) patients]. Lamotrigine caused adverse events in 11 (25%), of which rash in three (7%) and elevations of creatinine in four (9%) were the most common. The preferred lamotrigine dose was 25 mg twice daily. CONCLUSIONS. As there are few differences between the two treatments in efficacy, lamotrigine 25 mg twice daily might be the first choice as it is associated with fewer adverse effects in our population

Exactly solvable model of superstring in Ramond-Ramond plane wave background

We describe in detail the solution of type IIB superstring theory in the maximally supersymmetric plane-wave background with constant null Ramond-Ramond 5-form field strength. The corresponding light-cone Green-Schwarz action found in hep-th/0112044 is quadratic in both bosonic and fermionic coordinates. We find the spectrum of the light-cone Hamiltonian and the string representation of the supersymmetry algebra. The superstring Hamiltonian has a ``harmonic-oscillator'' form in both the string-oscillator and the zero-mode parts and thus has discrete spectrum in all 8 transverse directions. We analyze the structure of the zero-mode sector of the theory, establishing the precise correspondence between the lowest-lying ``massless'' string states and the type IIB supergravity fluctuation modes in the plane-wave background. The zero-mode spectrum has certain similarity to the supergravity spectrum in AdS_5 x S^5 of which the plane-wave background is a special limit. We also compare the plane-wave string spectrum with expected form of the light-cone gauge spectrum of superstring in AdS_5 x S^5.Comment: 33 pages, latex. v4: minor sign corrections in (1.5) and (3.62), to appear in PR

On the recurrence and robust properties of Lorenz'63 model

Lie-Poisson structure of the Lorenz'63 system gives a physical insight on its dynamical and statistical behavior considering the evolution of the associated Casimir functions. We study the invariant density and other recurrence features of a Markov expanding Lorenz-like map of the interval arising in the analysis of the predictability of the extreme values reached by particular physical observables evolving in time under the Lorenz'63 dynamics with the classical set of parameters. Moreover, we prove the statistical stability of such an invariant measure. This will allow us to further characterize the SRB measure of the system.Comment: 44 pages, 7 figures, revised version accepted for pubblicatio