Matter induced charge symmetry breaking and pion form factor in nuclear medium

Medium modification of pion form factor has been evaluated in asymmetric nuclear matter. It is shown that both the shape and the pole position of the pion form factor in dense asymmetric nuclear matter is different from its vacuum counterpart with $\rho$-$\omega$ mixing. This is due to the density and asymmetry dependent $\rho$-$\omega$ mixing which could even dominate over its vacuum counterpart in matter. Effect of the in-medium pion factor on experimental observables {\it e.g.}, invariant mass distribution of lepton pairs has been demonstrated.Comment: Final Version to appear in Jour. Phys.

Nonmodal energy growth and optimal perturbations in compressible plane Couette flow

Nonmodal transient growth studies and estimation of optimal perturbations have been made for the compressible plane Couette flow with three-dimensional disturbances. The maximum amplification of perturbation energy over time, $G_{\max}$, is found to increase with increasing Reynolds number ${\it Re}$, but decreases with increasing Mach number $M$. More specifically, the optimal energy amplification $G_{\rm opt}$ (the supremum of $G_{\max}$ over both the streamwise and spanwise wavenumbers) is maximum in the incompressible limit and decreases monotonically as $M$ increases. The corresponding optimal streamwise wavenumber, $\alpha_{\rm opt}$, is non-zero at M=0, increases with increasing $M$, reaching a maximum for some value of $M$ and then decreases, eventually becoming zero at high Mach numbers. While the pure streamwise vortices are the optimal patterns at high Mach numbers, the modulated streamwise vortices are the optimal patterns for low-to-moderate values of the Mach number. Unlike in incompressible shear flows, the streamwise-independent modes in the present flow do not follow the scaling law $G(t/{\it Re}) \sim {\it Re}^2$, the reasons for which are shown to be tied to the dominance of some terms in the linear stability operator. Based on a detailed nonmodal energy analysis, we show that the transient energy growth occurs due to the transfer of energy from the mean flow to perturbations via an inviscid {\it algebraic} instability. The decrease of transient growth with increasing Mach number is also shown to be tied to the decrease in the energy transferred from the mean flow ($\dot{\mathcal E}_1$) in the same limit

ESG Activities, Political Contributions, and Firm Performance

This dissertation is comprised of two distinct empirical papers which I document in two separate chapters. In the first chapter, I empirically examine the impact of banks’ environmental, social, and governance (ESG) practices on banking efficiency. Using a sample of 578 international banks over the years 2011-2019, I employ a data envelopment analysis (DEA) method to estimate banks’ technical efficiency scores. My baseline Tobit regressions reveal that high ESG performance significantly reduces banks’ efficiency. Further, I find that this relationship is non-linear at very high levels of ESG scores. These findings are consistent across the social (S) and governance (G) dimensions of ESG, across banks with different sizes and specializations, and across banks from America, Asia, and Oceania regions. I separately control for World Bank’s country-wise governance indicators and find consistent results for each of them. My results survive a couple of robustness tests based on Simar and Wilson (2007) two-stage efficiency analysis and fractional probit regressions. For further robustness, I test for and subsequently obtain persistence of the diminishing efficiency. I use a two-step system Generalized Method of Moments (GMM) estimation to deal with potential endogeneity. My channel regressions suggest that the negative effect is mainly attributed to significant reductions in bank loans and other operating assets. With this novel evidence, this chapter imparts new direction for further research in the growing literature of ESG issues in banking and finance. In the second chapter, I empirically explore the impact of political connections of U.S. suppliers and buyers. Prior evidence, although mixed, suggest that firm performance is significantly associated with its own political contributions. However, the link between firms’ performance and political connections of their suppliers and buyers is yet to be explored. I examine whether performance of U.S. firms is affected by the changes in political contributions of their supplier and buyers. Based on a large sample of U.S. nonfinancial firms and their politically connected suppliers and buyers from 1996 to 2018, my baseline findings reveal that firms’ profitability, value, liquidity, and debt level reduce significantly in response to increases in lobbying expenditures of their suppliers, supporting the bargaining power perspective of political connections. Further, I find that firms exhibit stronger liquidity and increased internal investments following rises in lobbying expenditures of their buyers, suggesting the cash-flow perspective of political contributions. These findings survive a set of robustness tests based on change-on-change regressions and propensity score matching. This chapter provides the first evidence on the link between firm performance and political contributions of their suppliers and buyers. This study shall be of substantial interest to academics, business organizations, and investors who are concerned about the impact that political connections impose on U.S. corporations

Quenching of light hadrons at RHIC in a collisional energy loss scenario

We evaluate the nuclear suppression factor, $R_{AA}(p_T)$ for light hadrons by taking into account the collisional energy loss. We show that in the measured $p_T$ domain of RHIC the elastic process is the dominant mechanism for the partonic energy loss.Comment: 4 pages with 3 figures, Quark Matter 2008 Proceeding

Gain-assisted slow to superluminal group velocity manipulation in nano-waveguides

We study the energy propagation in subwavelength waveguides and demonstrate that the mechanism of material gain, previously suggested for loss compensation, is also a powerful tool to manipulate dispersion and propagation characteristics of electromagnetic pulses at the nanoscale. We show theoretically that the group velocity in lossy nano-waveguides can be controlled from slow to superluminal values by the material gain and waveguide geometry and develop an analytical description of the relevant physics. We utilize the developed formalism to show that gain-assisted dispersion management can be used to control the transition between ``photonic-funnel'' and ``photonic-compressor'' regimes in tapered nano-waveguides. The phenomenon of strong modulation of group velocity in subwavelength structures can be realized in waveguides with different geometries, and is present for both volume and surface-modes.Comment: Some changes in the abstract and Fig.1. No results affecte

LIVE HOG AND PORK IMPORTS: PAST AND PROJECTED CONSEQUENCES FOR THE U.S. PORK SECTOR

The U.S. pork sector is modeled to simulate the effects of alternative import levels on prices, production, consumption, farm receipts, and consumer expenditures. Over the 1983-1985 period, producers annually received $600 million less due to increasing imports than if imports had remained at the 1979-1982 average. Farm prices and slaughter were lower by$2.21 per hundredweight and .1 million head annually, respectively. Four simulations reflecting alternative import paths over the period 1986-1992 were examined. With lower imports (relative to current levels), production and farm prices rise significantly in the long run; consumers purchase less and pay more.International Relations/Trade,

Nonperturbative corrections to B -> X_s l^+ l^- with phase space restrictions

We study nonperturbative corrections up to O(1/m_b^3) in the inclusive rare B decay B -> X_s l^+ l^- by performing an operator product expansion. The values of the matrix elements entering at this order are unknown and introduce uncertainties into physical quantities. Imposing a phase space cut to eliminate the $c \bar{c}$ resonances we find that the O(1/m_b^3) corrections introduce an O(10%) uncertainty in the measured rate. We also find that the contributions arising at O(1/m_b^3) are comparable to the ones arising at O(1/m_b^2) over the entire region of phase space.Comment: 7 pages, 2 figures, revte

Analisis Fitur Fraktal Citra Termogram sebagai Pendukung Deteksi Dini Kanker Payudara

Deteksi dini penyakit kanker payudara di Indonesia masih terkendala sejumlah persoalan sepertitingkat pendidikan, kondisi sosial ekonomi, pemahaman dan penanganan yang kurang tepat. Haltersebut menyebabkan 40% sampai 70% pasien kanker payudara datang ke dokter dal am statuskanker stadium lanjut. Pendeteksian dini kanker payudara adalah sangat penting untuk membantupenanganan penyakit kanker payudara secara cepat. Tujuan utama penelitian ini adalahmenganalisis fitur fraktal pada citra termogram untuk mendukung deteksi dini kanker payudara.Penelitian ini menggunakan citra termal jaringan payudara normal dan citra termal kankerpayudara. Tahapan-tahapan pada penelitian ini adalah pengolahan awal citra (preprocessing) yaitukonversi citra berwarna (RGB) ke citra skala keabuan (grayscale), pengubahan kontras, croppingobyek, proses binerisasi, serta ekstraksi fitur citra untuk menghitung dimensi fraktal. Hasilpenelitian menunjukan bahwa fitur fraktal yaitu dimensi fraktal dapat digunakan untukmembedakan antara citra termal payudara normal dengan citra termal kanker payudara. Dimensifraktal citra termal payudara normal lebih kecil yaitu 1,0725 sampai 1,2689 sedangkan pada citratermal kanker payudara yaitu 1,4581 sampai 1,8515

Inelastic neutron scattering in random binary alloys : an augmented space approach

Combining the augmented space representation for phonons with a generalized version of Yonezawa-Matsubara diagrammatic technique, we have set up a formalism to seperate the coherent and incoherent part of the total intensity of thermal neutron scattering from disordered alloys. This is done exacly without taking any recourse to mean-field like approximation (as done previously). The formalism includes disorder in masses, force constants and scattering lengths. Implementation of the formalism to realistic situations is performed by an augmented space Block recursion which calculates entire Green matrix and self energy matrix which in turn is needed to evaluate the coherent and incoherent intensities. we apply the formalism to NiPd and NiPt alloys. Numerical results on coherent and incoherent scattering cross sections are presented along the highest symmetry directions. Finally the incoherent intensities are compared with the CPA and also with experiments.Comment: 18 pages, 13 figure