Entropy and Multifractality in Relativistic Ion-Ion Collisions

Entropy production in multiparticle systems is investigated by analysing the experimental data on ion-ion collision at AGS and SPS energies and comparing the findings with those reported earlier for hadron-hadron, hadron-nucleus and nucleus-nucleus collisions. It is observed that the entropy produced in limited and full phase space, when normalised to maximum rapidity exhibits a kind of scaling which is nicely supported by Monte Carlo model \hij. Using the R\'{e}nyi's order-q information entropy, multifractal characteristics of particle production are examined in terms of Generalized dimensions, D$_{q}$. Nearly the same values of multifractal specific heat, $c$ observed in hadronic and ion-ion collisions over a wide range of incident energies suggest that the quantity $c$ may be used as a universal characteristic of multiparticle production in hadron-hadron, hadron-nucleus and nucleus-nucleus collisions.Comment: 17 pages, 5 figures, 2 table

Event-by-Event Fluctuations Clusterization and Entropy Production in AA Collisions at AGS and SPS Energies

Event-by-event (ebe) fluctuations in mean pseudorapidity values of relativistic charged particles in full phase space is studied by analysing experimental data on $^{16}O-AgBr$ collisions at 14.5A, 60A, and 200A GeV/c and $^{32}S-AgBr$ collisions at 200A GeV/c. The findings are compared with the prediction of A Multi-Phase Transport(\amm) model and those obtained from the analysis of correlation free Monte-Carlo events. Fluctuations in mean pseudorapidity distributions are noticed to be in excess to that expected from the statistically independent particle emission. The observed dependence of the fluctuation strength measure parameter,$\phi$ on the beam energy and number of participating target nucleons indicate that nucleus-nucleus collisions can not be treated as simple superposition of multiple nucleon-nucleon interactions. Presence of clusters or jet-like phenomena in multihadron final states are searched for on ebe basis by using the concept of Jaynes Shannon entropy. The findings indicate the presence of cluster like objects in the experimental data with their size and frequency increasing with increasing beam energy. These observations, in turn suggest that the clustering or jet-like algorithm adopted in the present study may be used as a tool for triggering different classes of events.Comment: International Journal of Modern Physics E, to be published(accepted

Correlations and Event-by-Event Fluctuations in High Multiplicity Events Produced in 208^{208}Pb-208^{208}Pb Collisions

Analysis of high multiplicity events produced in 158A GeV/c $^{208}$Pb-$^{208}$Pb collisions is carried out to study the event-by-event fluctuations. The findings reveal that the method of scaled factorial moments can be used to identify the events having densely populated narrow phase space bins. A few events sorted out adopting this approach are individually analyzed. It is observed that these events do exhibit large fluctuations in their pseudorapidity, $\eta$ and azimuthal angle, $\phi$ distributions arising out due to some dynamical reasons. Two particle $\Delta\eta$-$\Delta\phi$ correlation study applied to these events too indicates that some complex two-dimensional structure of significantly high magnitude are present in these events which might have some dynamical origin. The findings reveal that the method of scaled factorial moments may be used as an effective triggering for events with large dynamical fluctuations.Comment: 20 pages, 7 figures (Accepted for publication in Advances in High Energy Physics

Foreign Direct Investment, Exports, and Domestic Output in Pakistan

The impact of the policy reform on economic performance has been one of the stifling issues in development economics in the recent years. Since the middle 1970s, there has been considerable progress in the trade reform in the most developing countries, turning from an import substitution strategy to export-oriented approach. Pakistan also follows export-oriented policies. Pakistan’s trade pattern and trade policy have been moving towards fewer and fewer controls, tariffs rates have come tumbling down. Export-led-growth hypothesis (ELG) suggests that due to positive correlation between export and growth, therefore, export-oriented policies contribute to economic growth. Thus, international trade and development theory suggests that export growth contributes positively to economic growth. On the basis of this framework, most empirical work on the effects of export promoting strategy followed in developing countries evaluated openness with trade. Empirical research about the effect of this liberalisation process has treated export as principal channel for growth. The relationship with exports and growth, grounded in endogenous growth theory, has been tested for Pakistan.

Forward-Backward Multiplicity Correlations in Relativistic Heavy-Ion Collisions

Forward-backward multiplicitycorrelations are investigated by analyzing the experimental data on 6O-AgBr collisions at 14.5A, 60A and 200A GeV/c and the findings are compared with the predictions of Monte Carlo model, hIJING. the findings indicate that the observed correlations are mainly of short-range in nature which arise due to the decay of clusters and (or) resonances produced in the central rapidity region. the result reveal that the range of F-B correlations extend to rather longer range with increasing beam energy which might be due to overall multiplicity fluctuations arising because of nuclear geometry. however, there is no evidence for the presence of long-range correlations even at the highest beam energy considered

Contributions of Jets in Net Charge Fluctuations from the Beam Energy Scan at RHIC and LHC

Dynamical net charge fluctuations have been studied in ultra-relativistic heavy-ion collisions from the beam energy scan at RHIC and LHC energies by carrying out the hadronic model simulation. Monte Carlo model, HIJING is used to generate events in two different modes, HIJING-default with jet quenching switched off and jet/minijet production switched off. A popular variable, $\nu_{[+-,dyn]}$ is used to study the net charge fluctuations in different centrality bins and the findings are compared with the available experimental values reported earlier. Although the broad features of net charge fluctuations are reproduced by the HIJING, yet the model predicts the larger magnitude of fluctuations as compared to the one observed in experiments. The role of jets/minijets production in reducing the net charge fluctuations is, however distinctly visible from the analysis of the two types of HIJING events. Furthermore, $dN_{ch}/d\eta$ and $1/N$ scaling is partially exhibited which is due to the fact that in HIJING, nucleus-nucleus collisions are treated as multiple independent nucleon-nucleon collisions.Comment: 27 pages, 11 figures, 5 tables Accepted for publication in Journal Advances in High Energy Physic

Aging and Crossovers in Phase-Separating Fluid Mixtures

We use state-of-the-art molecular dynamics simulations to study hydrodynamic effects on aging during kinetics of phase separation in a fluid mixture. The domain growth law shows a crossover from a diffusive regime to a viscous hydrodynamic regime. There is a corresponding crossover in the autocorrelation function from a power-law behavior to an exponential decay. While the former is consistent with theories for diffusive domain growth, the latter results as a consequence of faster advective transport in fluids for which an analytical justification has been provided.Comment: 6 pages, 4 figure

Outcome and cost effectiveness of autobiographically guided surgical clip placement for tumor localization in patients undergoing neo-adjuvant chemotherapy for breast cancer.

Abstract BACKGROUND: To determine the outcome and cost saving by placing ultrasound guided surgical clips for tumor localization in patientsundergoing neo-adjuvant chemotherapy for breast cancer. MATERIALS AND METHODS: This retrospective cross sectional analytical study was conducted at the Department of Diagnostic Radiology, Aga Khan University Hospital, Karachi, Pakistan from January to December 2014. A sample of 25 women fulfilling our selection criteria was taken. All patients came to our department for ultrasound guided core biopsy of suspicious breast lesions and clip placement in the index lesion prior to neo-adjuvant chemotherapy. All the selected patients had biopsy proven breast cancer. RESULTS: The mean age was 45 ± 11.6 years. There were no complications seen after clip placement in terms of clip migration or hemorrhage. The cost of commercially available markers was approximately PKR 9,000 (US$90) and that of the surgical clip was PKR 900 (US$ 9). The cost of surgical clips in 25 patients was PKR 22,500 (US$225), when compared to the commercially available markers which may have incurred a cost of PKR 225,000 (US$ 2,250). The total cost saving for 25 patients was PKR 202,500 (US$2, 025), making it PKR 8100 (US$ 81) per patient. CONCLUSIONS: The results of our study show that ultrasound guided surgical clip placement in index lesions prior to neo-adjuvant therapy is a safe and cost effective method to identify tumor bed and response to treatment for further management

Study of the difference in quality of life and caregiver burden among patients with schizophrenia and rheumatoid arthritis

Background: Quality of life (QOL) is a measure to see an individual’s adaptation and feeling of wellbeing and adjustment with the surroundings. Schizophrenia and rheumatoid arthritis (RA) both are chronic and disabling disorders supposed to have significant effect on quality of life. Also chronicity and disability of these disorders can be directly proportional to the caregiver burden.Methods: Comparative study assessing quality of life and caregiver burden between persons with schizophrenia and RA.Results: 50% of the schizophrenia group as well as the RA group were unemployed, suggesting the magnitude of the disability levels caused by the illness. Only 33% of patients with schizophrenia were married, unlike patients with RA where 83% were married. Of all the four domains of the World Health Organization quality of life instrument (WHO-QOL BREF) both the groups scored highest in the physical domain and least in the psychological domain and the difference between the two groups was not statistically significant in all the four domains. Burden among the caregivers of schizophrenic patients was comparatively high on BAS than caregivers of rheumatoid arthritis. The mean duration of illness in patients with schizophrenia was significantly higher than patients with RA.Conclusions: RA is a chronic disorder and physical in nature with full insight in the patients. While as schizophrenia is characterized as a chronic mental illness with poor prognosis and no insight. QOL is expected to be less in schizophrenic patients. There is no significant difference in QOL except in physical domain in which patients with schizophrenia scored significantly better than patients with RA. The social domain of QOL was the only one in which schizophrenic patients did poorly, though not statistically significant. Also care giver burden was more among caregivers of schizophrenic patients and that can be attributed to lack of insight