The X(3872) at the Tevatron

I report results on the X(3872) from the Tevatron. Mass and other properties have been studied, with a focus on new results on the dipion mass spectrum in X -> J/PsiPi^+Pi^- decays. Dipions favor interpreting the decay as J/PsiRho, implying even C-parity for the X. Modeling uncertainties do not allow distinguishing between S- and P-wave decays of the J/PsiRho mode. Effects of Rho-Omega interference in X decay are also introduced.Comment: Contribution to PANIC05, Santa Fe, 24-28 October 2005 (4 pages, 6 plots

Fiscal space for health expenditure in Mozambique: blocking effectiveness of international funds through budget support

Mexico AIDS Conference 200

Origin of layer dependence in band structures of two-dimensional materials

We study the origin of layer dependence in band structures of two-dimensional materials. We find that the layer dependence, at the density functional theory (DFT) level, is a result of quantum confinement and the non-linearity of the exchange-correlation functional. We use this to develop an efficient scheme for performing DFT and GW calculations of multilayer systems. We show that the DFT and quasiparticle band structures of a multilayer system can be derived from a single calculation on a monolayer of the material. We test this scheme on multilayers of MoS$_2$, graphene and phosphorene. This new scheme yields results in excellent agreement with the standard methods at a fraction of the computation cost. This helps overcome the challenge of performing fully converged GW calculations on multilayers of 2D materials, particularly in the case of transition metal dichalcogenides which involve very stringent convergence parameters

Substrate screening effects on the quasiparticle band gap and defect charge transition levels in MoS2_2

Monolayer MoS$_2$ has emerged as an interesting material for nanoelectronic and optoelectronic devices. The effect of substrate screening and defects on the electronic structure of MoS$_2$ are important considerations in the design of such devices. Here, we present ab initio density functional theory (DFT) and GW calculations to study the effect of substrate screening on the quasiparticle band gap and defect charge transition levels (CTLs) in monolayer MoS$_2$. We find a giant renormalization to the free-standing quasiparticle band gap by 350 meV and 530 meV in the presence of graphene and graphite as substrates, respectively. Our results are corroborated by recent experimental measurements on these systems using scanning tunneling spectroscopy and photoluminescence excitation spectroscopy. Sulfur vacancies are the most abundant native defects found in MoS$_2$. We study the CTLs of these vacancies in MoS$_2$ using the DFT+GW formalism. We find (+1/0) and (0/-1) CTLs appear in the pristine band gap of MoS$_2$. Substrate screening results in renormalization of the (0/-1) level, with respect to the valence band maximum (VBM), by the same amount as the gap. This results in the pinning of the (0/-1) level about $\sim$500 meV below the conduction band minimum for the free-standing case as well as in the presence of substrates. The (+1/0) level, on the other hand, lies less than 100 meV above the VBM for all the cases

Energy-aware dynamic pricing model for cloud environments

Energy consumption is a critical operational cost for Cloud providers. However, as commercial providers typically use fixed pricing schemes that are oblivious about the energy costs of running virtual machines, clients are not charged according to their actual energy impact. Some works have proposed energy-aware cost models that are able to capture each client’s real energy usage. However, those models cannot be naturally used for pricing Cloud services, as the energy cost is calculated after the termination of the service, and it depends on decisions taken by the provider, such as the actual placement of the client’s virtual machines. For those reasons, a client cannot estimate in advance how much it will pay. This paper presents a pricing model for virtualized Cloud providers that dynamically derives the energy costs per allocation unit and per work unit for each time period. They account for the energy costs of the provider’s static and dynamic energy consumption by sharing out them according to the virtual resource allocation and the real resource usage of running virtual machines for the corresponding time period. Newly arrived clients during that period can use these costs as a baseline to calculate their expenses in advance as a function of the number of requested allocation and work units. Our results show that providers can get comparable revenue to traditional pricing schemes, while offering to the clients more proportional prices than fixed-price models.Peer ReviewedPostprint (author's final draft

International diffusion of energy technology : report of a workshop held on June 2-3, 1976, at Dedham, Massachusetts

Prepared in association with Center for International Studies, Massachusetts Institute of TechnologyGrant #E(49-18)-2295, Task Order No.2, from the Energy Research and Development Administratio

"Fear of stigma is stronger than fear of death": a workplace initiative to reduce sickness and death due to HIV/AIDS among health staff in Malawi

Mexico AIDS Conference 200

Disrupting Innovation Driven by Governmental Regulatory Targeting, Not Slow Guided Incremental Innovation Involving Incumbents is What is Needed to Transform the Industrial State

Strategic Niche Management and Transition Management have been promoted as useful avenues to pursue in order to achieve both specific product or process changes and system transformation by focusing on technology development through evolutionary and co-evolutionary processes, guided by government and relevant stakeholders. However, these processes are acknowledged to require decades to achieve their intended changes, a timeframe that is too long to adequately address many of the environmental and social issues we are facing. An approach that involves incumbents and does not consider targets that look beyond reasonably foreseeable technology is likely to advance a model where incumbents evolve rather than being replaced or displaced. Sustainable development requires both disruptive technological and institutional changes, the latter including stringent regulation, integration beyond coordination of disparate goals, and changes in incentives to enable new voices to contribute to integrated systems and solutions. This paper outlines options for a strong governmental role in setting future sustainability goals and the pathways for achieving them