Evaluation of the Effectiveness of Biosand Water Filters in Removing Fecal Coliforms Over Time (Years) in Rural Rwanda

Graduate Applie

THE CHANGING WORK FORCE AND IMPLICATIONS FOR WORK AND FAMILY

Labor and Human Capital,

Regular resolution for CNF of bounded incidence treewidth with few long clauses

We demonstrate that Regular Resolution is FPT for two restricted families of CNFs of bounded incidence treewidth. The first includes CNFs having at most $p$ clauses whose removal results in a CNF of primal treewidth at most $k$. The parameters we use in this case are $p$ and $k$. The second class includes CNFs of bounded one-sided (incidence) treewdth, a new parameter generalizing both primal treewidth and incidence pathwidth. The parameter we use in this case is the one-sided treewidth

Continuum percolation for Cox point processes

We investigate continuum percolation for Cox point processes, that is, Poisson point processes driven by random intensity measures. First, we derive sufficient conditions for the existence of non-trivial sub- and super-critical percolation regimes based on the notion of stabilization. Second, we give asymptotic expressions for the percolation probability in large-radius, high-density and coupled regimes. In some regimes, we find universality, whereas in others, a sensitive dependence on the underlying random intensity measure survives.Comment: 21 pages, 5 figure

Phase transitions for the Boolean model of continuum percolation for Cox point processes

We consider the Boolean model with random radii based on Cox point processes. Under a condition of stabilization for the random environment, we establish existence and non-existence of subcritical regimes for the size of the cluster at the origin in terms of volume, diameter and number of points. Further, we prove uniqueness of the infinite cluster for sufficiently connected environments.Comment: 22 pages, 2 figure

How much do charm sea quarks affect the charmonium spectrum?

The properties of charmonium states are or will be intensively studied by the B-factories Belle II and BESIII, the LHCb and PANDA experiments and at a future Super-c-tau Factory. Precise lattice calculations provide valuable input and several results have been obtained by simulating up, down and strange quarks in the sea. We investigate the impact of a charm quark in the sea on the charmonium spectrum, the renormalization group invariant charm-quark mass and the scalar charm-quark content of charmonium. The latter is obtained by the direct computation of the mass-derivatives of the charmonium masses. We do this investigation in a model, QCD with two degenerate charm quarks. The absence of light quarks allows us to reach very small lattice spacings down to 0.023 fm. By comparing to pure gauge theory we find that charm quarks in the sea affect the hyperfine splitting at a level below 2%. The most significant effects are 5% in the quark mass and 3% in the value of the charm quark content of the eta_c meson. Given that we simulate two charm quarks these estimates are upper bounds for the contribution of a single charm quark. We show that lattice spacings <0.06 fm are needed for safe continuum extrapolations of the charmonium spectrum with O(a) improved Wilson quarks. A useful relation for the projection to the desired parity of operators in two-point functions computed with twisted mass fermions is proven.Comment: 25 pages, 8 figure

The changing role of the international community in the MDG achievement in Bolivia

Millennium Development Goal number 8 (MDG8) concerns those external flows (Official Development Assistance, trade and debt relief) that ought to help developing countries achieve the MDGs by 2015. This paper reviews the role of these MDG8-related external flows in the case of Bolivia. Riding on high international prices for its major exports, and on fiscal expansion, remittances and debt forgiveness, Bolivia has experienced solid economic performance in the past few years. This economic performance coupled with the recent increase in social public expenditures by the government has increased the likelihood that the country will achieve all of the MDGs by 2015, except probably for MDG 2. These advances have been achieved in a period of radical change in Bolivia’s dependence on MDG8-related external flows. The composition of external finance in public expenditure has shifted from domination by ODA and debt forgiveness in the first half of the decade to domination by trade, mainly through revenues from hydrocarbon exports. Our findings support the idea that the provision of additional financial resources may not be the priority with regard to organising support to MDG achievements. Spending efficiently and effectively seems to be a more important area for support in Bolivia. As far as trade is concerned, Bolivia already enjoys good market access in its main markets, thus better access through lower non-tariff barriers may be more relevant than improving access in terms of tariffs. Moreover access to markets would be easier if Bolivia were better integrated with world markets, with its regional neighbours in particular. This calls for the support of the international community through aid for trade (AfT), which has instead been worryingly dwindling in recent years. Finally, we argue that MDG8 could be pursued in Bolivia through support for improving access to technology and access to affordable drugs.Bolivia, MDGs, aid, trade, debt

Charm quark effects on the strong coupling extracted from the static force

We compute the fermionic contribution to the strong coupling $\alpha_{qq}$ extracted from the static force in Lattice QCD up to order $g^4$ in perturbation theory. This allows us to subtract the leading fermionic lattice artifacts from recent determinations of $\alpha_{qq}$ produced in simulations of two dynamical charm quarks. Moreover, by using a suitable parametrization of the $\beta_{qq}$-function, we can evaluate the charm loop effects on $\alpha_{qq}$ in the continuum limit.Comment: 8 pages, 2 figures; Proceedings of the 35th International Symposium on Lattice Field Theory, Granada, Spai