Linking safety nets, social protection, and poverty reduction

"In Africa and elsewhere, safety nets were promoted in the 1980s as a response to the (presumably short-term) adverse effects of structural adjustment. Though some safety nets had a developmental component, safety nets are still largely associated with the idea of a short-term buffer. “Social protection” is a newer term that incorporates safety net programs but also includes a role for renewed state involvement, emphasizes a longer-term developmental approach, includes social assistance and social insurance, and is often advocated as a right rather than a reactive form of relief. Social protection policy addresses not only programs aimed at reducing the impact of shocks and coping with their aftermath, but also interventions designed to prevent shocks and destitution in the first place. Most societies have private interhousehold, intrafamily, and intrahousehold transfers that promote resilience to shocks, mitigating their negative effects. However, in countries or communities where people are universally poor, there is less to share, particularly in times of shocks that affect all or many in the society (such as drought, floods, AIDS, or widespread structural unemployment) — which is precisely when the need for help is most critical." from TextSafety nets ,Social protection ,Transfers ,

Quantum Interactive Proofs with Competing Provers

This paper studies quantum refereed games, which are quantum interactive proof systems with two competing provers: one that tries to convince the verifier to accept and the other that tries to convince the verifier to reject. We prove that every language having an ordinary quantum interactive proof system also has a quantum refereed game in which the verifier exchanges just one round of messages with each prover. A key part of our proof is the fact that there exists a single quantum measurement that reliably distinguishes between mixed states chosen arbitrarily from disjoint convex sets having large minimal trace distance from one another. We also show how to reduce the probability of error for some classes of quantum refereed games.Comment: 13 pages, to appear in STACS 200

New Approximability Results for the Robust k-Median Problem

We consider a robust variant of the classical $k$-median problem, introduced by Anthony et al. \cite{AnthonyGGN10}. In the \emph{Robust $k$-Median problem}, we are given an $n$-vertex metric space $(V,d)$ and $m$ client sets $\set{S_i \subseteq V}_{i=1}^m$. The objective is to open a set $F \subseteq V$ of $k$ facilities such that the worst case connection cost over all client sets is minimized; in other words, minimize $\max_{i} \sum_{v \in S_i} d(F,v)$. Anthony et al.\ showed an $O(\log m)$ approximation algorithm for any metric and APX-hardness even in the case of uniform metric. In this paper, we show that their algorithm is nearly tight by providing $\Omega(\log m/ \log \log m)$ approximation hardness, unless ${\sf NP} \subseteq \bigcap_{\delta >0} {\sf DTIME}(2^{n^{\delta}})$. This hardness result holds even for uniform and line metrics. To our knowledge, this is one of the rare cases in which a problem on a line metric is hard to approximate to within logarithmic factor. We complement the hardness result by an experimental evaluation of different heuristics that shows that very simple heuristics achieve good approximations for realistic classes of instances.Comment: 19 page

Photon number discrimination without a photon counter and its application to reconstructing non-Gaussian states

The non-linearity of a conditional photon-counting measurement can be used to `de-Gaussify' a Gaussian state of light. Here we present and experimentally demonstrate a technique for photon number resolution using only homodyne detection. We then apply this technique to inform a conditional measurement; unambiguously reconstructing the statistics of the non-Gaussian one and two photon subtracted squeezed vacuum states. Although our photon number measurement relies on ensemble averages and cannot be used to prepare non-Gaussian states of light, its high efficiency, photon number resolving capabilities, and compatibility with the telecommunications band make it suitable for quantum information tasks relying on the outcomes of mean values.Comment: 4 pages, 3 figures. Theory section expanded in response to referee comment

Approximating the minimum directed tree cover

Given a directed graph $G$ with non negative cost on the arcs, a directed tree cover of $G$ is a rooted directed tree such that either head or tail (or both of them) of every arc in $G$ is touched by $T$. The minimum directed tree cover problem (DTCP) is to find a directed tree cover of minimum cost. The problem is known to be $NP$-hard. In this paper, we show that the weighted Set Cover Problem (SCP) is a special case of DTCP. Hence, one can expect at best to approximate DTCP with the same ratio as for SCP. We show that this expectation can be satisfied in some way by designing a purely combinatorial approximation algorithm for the DTCP and proving that the approximation ratio of the algorithm is $\max\{2, \ln(D^+)\}$ with $D^+$ is the maximum outgoing degree of the nodes in $G$.Comment: 13 page

Experimental determination of the degree of quantum polarisation of continuous variable states

We demonstrate excitation-manifold resolved polarisation characterisation of continuous-variable (CV) quantum states. In contrast to traditional characterisation of polarisation that is based on the Stokes parameters, we experimentally determine the Stokes vector of each excitation manifold separately. Only for states with a given photon number does the methods coincide. For states with an indeterminate photon number, for example Gaussian states, the employed method gives a richer and more accurate description. We apply the method both in theory and in experiment to some common states to demonstrate its advantages.Comment: 5 page

Characteristics of summer-time energy exchange in a high Arctic tundra heath 2000–2010

Global warming will bring about changes in surface energy balance of Arctic ecosystems, which will have implications for ecosystem structure and functioning, as well as for climate system feedback mechanisms. In this study, we present a unique, long-term (2000–2010) record of summer-time energy balance components (net radiation, R n; sensible heat flux, H; latent heat flux, LE; and soil heat flux, G) from a high Arctic tundra heath in Zackenberg, Northeast Greenland. This area has been subjected to strong summer-time warming with increasing active layer depths (ALD) during the last decades. We observe high energy partitioning into H, low partitioning into LE and high Bowen ratio (β=H/LE) compared with other Arctic sites, associated with local climatic conditions dominated by onshore winds, slender vegetation with low transpiration activity and relatively dry soils. Surface saturation vapour pressure deficit (D s) was found to be an important variable controlling within-year surface energy partitioning. Throughout the study period, we observe increasing H/R n and LE/R n and decreasing G/R n and β, related to increasing ALD and decreasing soil wetness. Thus, changes in summer-time surface energy balance partitioning in Arctic ecosystems may be of importance for the climate system

"Real world" eligibility for sacubitril/valsartan in unselected heart failure patients: data from the Swedish Heart Failure Registry

Purpose: PARADIGM-HF demonstrated the superiority of sacubitril/valsartan over enalapril in patients with heart failure and reduced ejection fraction (HF-REF). How widely applicable sacubitril/valsartan treatment is in unselected patients with HF-REF is not known. We examined eligibility of patients with HF-REF for treatment with sacubitril/valsartan, according to the criteria used in PARADIGM-HF, in the Swedish Heart Failure Registry (SwedeHF). Methods: Patients were considered potentially eligible if they were not hospitalized, had symptoms (NYHA class II–IV) and a reduced LVEF (≤ 40%), and were prescribed an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) at a dose equivalent to enalapril ≥ 10 mg daily. In these patients, we evaluated further eligibility according to the main additional PARADIGM-HF inclusion criteria. Results: Of 12,866 outpatients in NYHA functional class II–IV with an LVEF ≤ 40%, 9577 were prescribed at least 10 mg of enalapril (or equivalent) daily. Complete additional data were available for 3099 of these patients (32.4%) and of them 75.5% were potentially eligible for treatment with sacubitril/valsartan. The most common reason for ineligibility was a low natriuretic peptide level (n = 462, 14.9%). Only a small proportion of patients were ineligible due to low eGFR or serum potassium level. Because only 78% of patients were taking ≥ 10 mg enalapril or equivalent daily, only 58.9% of all patients (75.5% of 78%) were eligible for sacubitril/valsartan. Conclusions: Between 34 and 76% of symptomatic patients with HF-REF in a ‘real world’ population are eligible for treatment with sacubitril/valsartan, depending on background ACEI/ARB dose. The most common reason for ineligibility is a low natriuretic peptide level

Reoptimization of Some Maximum Weight Induced Hereditary Subgraph Problems

The reoptimization issue studied in this paper can be described as follows: given an instance I of some problem Π, an optimal solution OPT for Π in I and an instance I′ resulting from a local perturbation of I that consists of insertions or removals of a small number of data, we wish to use OPT in order to solve Π in I', either optimally or by guaranteeing an approximation ratio better than that guaranteed by an ex nihilo computation and with running time better than that needed for such a computation. We use this setting in order to study weighted versions of several representatives of a broad class of problems known in the literature as maximum induced hereditary subgraph problems. The main problems studied are max independent set, max k-colorable subgraph and max split subgraph under vertex insertions and deletion

Measurement of the branching ratio for beta-delayed alpha decay of 16N

While the 12C(a,g)16O reaction plays a central role in nuclear astrophysics, the cross section at energies relevant to hydrostatic helium burning is too small to be directly measured in the laboratory. The beta-delayed alpha spectrum of 16N can be used to constrain the extrapolation of the E1 component of the S-factor; however, with this approach the resulting S-factor becomes strongly correlated with the assumed beta-alpha branching ratio. We have remeasured the beta-alpha branching ratio by implanting 16N ions in a segmented Si detector and counting the number of beta-alpha decays relative to the number of implantations. Our result, 1.49(5)e-5, represents a 24% increase compared to the accepted value and implies an increase of 14% in the extrapolated S-factor