Deformation and weak decay of Lambda hypernuclei

We use the self-consistent mean-field theory to discuss the ground state and decay properties of $\Lambda$ hypernuclei. We first discuss the deformation of $\Lambda$ hypernuclei using the relativistic mean-field (RMF) approach. We show that, although most of hypernuclei have a similar deformation parameter to the core nucleus, the shape of $^{28}$Si is drastically altered, from oblately deformed to spherical, if a $\Lambda$ particle is added to this nucleus. We then discuss the pionic weak decay of neutron-rich $\Lambda$ hypernuclei using the Skyrme Hartree-Fock + BCS method. We show that, for a given isotope chain, the decay rate increases as a function of mass number, due to the strong neutron-proton interaction.Comment: A talk given at Sendai International Symposium on Strangeness Nuclear and Hadronic Systems (SENDAI08), Dec. 15-18, 2008, Sendai, Japa

Generalized Interference Alignment --- Part I: Theoretical Framework

Interference alignment (IA) has attracted enormous research interest as it achieves optimal capacity scaling with respect to signal to noise ratio on interference networks. IA has also recently emerged as an effective tool in engineering interference for secrecy protection on wireless wiretap networks. However, despite the numerous works dedicated to IA, two of its fundamental issues, i.e., feasibility conditions and transceiver design, are not completely addressed in the literature. In this two part paper, a generalised interference alignment (GIA) technique is proposed to enhance the IA's capability in secrecy protection. A theoretical framework is established to analyze the two fundamental issues of GIA in Part I and then the performance of GIA in large-scale stochastic networks is characterized to illustrate how GIA benefits secrecy protection in Part II. The theoretical framework for GIA adopts methodologies from algebraic geometry, determines the necessary and sufficient feasibility conditions of GIA, and generates a set of algorithms that can solve the GIA problem. This framework sets up a foundation for the development and implementation of GIA.Comment: Minor Revision at IEEE Transactions on Signal Processin

Economic Sanctions as Instruments of American Foreign Policy

Throughout history, military and economic powers have used economic sanctions, blockades and boycotts as parts of their policies against other countries for many reasons. The United States is no exception. The United States uses economic sanctions as a foreign policy tool to pressure other countries for human rights violations, nuclear proliferation and aggressions and international terrorism. There is an assumption that economic sanctions imposed by the United States will become more and more effective because the United States has become more and more economically and militarily powerful after the collapse of the Soviet Union. The United States is a sole global power both militarily and economically. The effectiveness of sanctions, however, cannot be measure by regime or behavior change of a target country. It is naive to believe that regime or behavior change of a regime can take place just because of American foreign policy. There are many instances in the past where American diplomatic actions failed to change the behavior of a regime. There are also many examples in the past where American military actions, especially military intervention in Vietnam, failed to produce behavior or a regime changes. There are many cases of economic sanctions that failed to produce behavior change of a regime. The imposition of economic sanctions, in one form or another, as an instrument of foreign policy developed over centuries. There are many good reasons why economic sanctions, in one form or another, such as blockades, boycotts and sieges, developed over centuries, and why some powerful countries are still using those as foreign policy tool. Economic sanctions are important and essential parts of effective and complex foreign policy. American foreign policy will be as simple as black and white and as weak as a paper tiger without economic sanctions. This thesis attempts to explain why economic sanctions are essential parts of American foreign policy. This thesis also examines arguments and counter-arguments regarding economic sanctions

Assessing trends and determinants of childhood undernutrition among urban poor and slum children in Bangladesh

This thesis aims to contribute to better understanding about trends and drivers of childhood undernutrition affecting urban poor and slum children in Bangladesh—a rapidly urbanizing country with one of the highest child stunting burdens in the world. The first thesis manuscript used serial population-representative data from Bangladesh Demographic and Health Surveys spanning over nearly two decades (2000-2018), and explored reasons for disparities in childhood linear growth status between urban poor and non-poor children. The manuscript findings highlighted urban poor children—compared to rural or other urban children—as a disproportionately disadvantaged subgroup for child undernutrition, and elicited maternal background factors as among primary predictors of the intra-urban child linear growth gap. The second thesis manuscript used primary data collected in urban slums and explored the role of maternal work as a potential predictor of nutritional outcomes in slum children. It found that children of working mothers were nearly twice more likely to be stunted than children of non-working mothers, but that family structures and availability of childcare support to mothers moderated the association in these settings. The third thesis manuscript then explored the effects of the COVID-19 pandemic on nutritional status of urban slum children, using primary data collected before- and after- the first wave of the pandemic in Bangladesh. It found that the average nutritional status of slum children had generally not deteriorated over the one-year sample period, but variations were apparent by slum area and household migration status

Impurity effect of Lambda hyperon on collective excitations of atomic nuclei

Taking the ground state rotational band in $^{24}$Mg as an example, we investigate the impurity effect of $\Lambda$ hyperon on collective excitations of atomic nuclei in the framework of non-relativistic energy density functional theory. To this end, we take into account correlations related to the restoration of broken symmetries and fluctuations of collective variables by solving the eigenvalue problem of a five-dimensional collective Hamiltonian for quadrupole vibrational and rotational degrees of freedom. The parameters of the collective Hamiltonian are determined with constrained mean-field calculations for triaxial shapes using the SGII Skyrme force. We compare the low-spin spectrum for $^{24}$Mg with the spectrum for the same nucleus inside $^{25}_{\Lambda}$Mg. It is found that the $\Lambda$ hyperon stretches the ground state band and reduces the $B(E2:2^+_1 \rightarrow 0^+_1)$ value by $\sim 9$, mainly by softening the potential energy surface towards the spherical shape, even though the shrinkage effect on the average proton radius is only $\sim0.5$.Comment: 16 pages, 5 figures, and 1 tabl

Keterkaitan antara Demokrasi Politik, Demokrasi Ekonomi dan Sistem Ekonomi Kerakyatan

Demokrasi politik merupakan syarat bagi berjalannya demokrasi ekonomi. Pelaksanaan demokrasi ekonomi akan terwujud bila terdapat kesejajaran antara sistem politik dan sistem ekonomi. Dalam sejarah perekonomian nasional, semangat demokrasi ekonomi sering dilanggar oleh menjurusnya sistem ekonomi nasional baik ke arah ekonomi kapitalistik atau ke sistem ekonomi terpusat. Sistem ekonomi kerakyatan yang bercirikan penegakan keadilan demokrasi ekonomi dan pemihakan terhadap yang lemah merupakan landasan dan sekaligus sebagai sarana bagi mewujudkan keadilan sosial bagi seluruh rakyat yang merupakan pilar utama demokrasi ekonomi