209 research outputs found

    Effects of \u3ci\u3eParthenium hysterophorus\u3c/i\u3e on Grassland Community in Nyando Sub-County, Kisumu County, Kenya

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    Parthenium hysterophorus is an invasive alien species native to South and Central America. The plant is ranked as one of the most dreaded weeds of the world. Parthenium hysterophorus affects grassland community through the release of allelochemicals that inhibit the germination and growth of grass species. However, little is known about its effects on native grassland community in Nyando sub-county of Kenya. Therefore, this study sought to investigate the effects of P. hysterophorus on grass species, livestock production and its control. A total of 121 farm household heads were interviewed using semi-structured interview schedules. Descriptive analysis and the T-test at 5% level of significance were used to analyse data. Sixty-three percent of respondents reported that P. hysterophorus replaced major native pasture species consequently reducing the quantity of milk yield per cow significantly by 3.81 litres. Majority households (98.3%) controlled P. hysterophorus by uprooting, slashing and hoeing while the remaining households used herbicides. The cost of controlling P. hysterophorus is expensive at about Kes. 6,253.33 per acre. Parthenium hysterophorus has the potential to negatively affect grasslands in Kenya with adverse impact on human livelihoods by reducing milk and beef production, lack of high quality nutrition food as well as the attainment of development targets such as those set in the Big Four Agenda, the Vision 2030 and the Sustainable Development Goals

    Experimental achievement of the entanglement assisted capacity for the depolarizing channel

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    We experimentally demonstrate the achievement of the entanglement assisted capacity for classical information transmission over a depolarizing channel. The implementation is based on the generation and local manipulation of 2-qubit Bell states, which are finally measured at the receiver by a complete Bell state analysis. The depolarizing channel is realized by introducing quantum noise in a controlled way on one of the two qubits. This work demonstrates the achievement of the maximum allowed amount of information that can be shared in the presence of noise and the highest reported value in the noiseless case.Comment: 4 pages, 3 figure

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    The allocation of time is a crucial decision that influences many aspects of household welfare. According to standard theory it depends on the potential wage rate of spouses relative to their domestic productivity. A major problem, however, is that individual productivities are not observed. As a consequence, an important source of difference in household living standards alongside with heterogeneity in preferences and wage rates, cannot be accounted for. This paper presents a new methodology to estimate individual domestic productivity based on the informational content of a standard time use survey, with time inputs observable but domestic output immeasurable. It provides empirical evidence based on a sample of French two-earner couples. As a test of the empirical validity of this approach, the paper shows that the estimate of female domestic productivity is a significant variable in explaining the overall intra-household distribution of resources

    Experimental Quantum Networking Protocols via Four-Qubit Hyperentangled Dicke States

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    We report the experimental demonstration of two quantum networking protocols, namely quantum 1->3 telecloning and open-destination teleportation, implemented using a four-qubit register whose state is encoded in a high-quality two-photon hyperentangled Dicke state. The state resource is characterized using criteria based on multipartite entanglement witnesses. We explore the characteristic entanglement-sharing structure of a Dicke state by implementing high-fidelity projections of the four-qubit resource onto lower-dimensional states. Our work demonstrates for the first time the usefulness of Dicke states for quantum information processing.Comment: 4 pages + Supplementary Information, 6 figures; revised version: Accepted for publication in Phys. Rev. Let

    Fully nonlocal quantum correlations

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    Quantum mechanics is a nonlocal theory, but not as nonlocal as the no-signalling principle allows. However, there exist quantum correlations that exhibit maximal nonlocality: they are as nonlocal as any non-signalling correlations and thus have a local content, quantified by the fraction pLp_L of events admitting a local description, equal to zero. Exploiting the link between the Kochen-Specker and Bell's theorems, we derive, from every Kochen-Specker proof, Bell inequalities maximally violated by quantum correlations. We then show that these Bell inequalities lead to experimental bounds on the local content of quantum correlations which are significantly better than those based on other constructions. We perform the experimental demonstration of a Bell test originating from the Peres-Mermin Kochen-Specker proof, providing an upper bound on the local content pL≲0.22p_L\lesssim 0.22.Comment: 9 pages, 5 figures and three tables. To appear in PR

    Development of a Toolkit for Participatory Management of Rural Watersheds in Kenya

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    Effective public participation is a foundation for sustainable watershed management, yet there are no demonstrated methods for or examples of its achievement in tropical semi-arid rural grassland watersheds of Kenya which support critical downstream water services. Within the Sustainable Management of Watersheds (SUMAWA) multidisciplinary international research project, a set of tools has been developed and tested to engage local communities and stakeholders in a dialogue and decision-making process to improve the development and management of the River Njoro Watershed in Kenya and reverse declining water quality and quantity problems. A toolkit manual based on the experience is under preparation for general distribution

    Engineering a C-Phase quantum gate: optical design and experimental realization

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    A two qubit quantum gate, namely the C-Phase, has been realized by exploiting the longitudinal momentum (i.e. the optical path) degree of freedom of a single photon. The experimental setup used to engineer this quantum gate represents an advanced version of the high stability closed-loop interferometric setup adopted to generate and characterize 2-photon 4-qubit Phased Dicke states. Some experimental results, dealing with the characterization of multipartite entanglement of the Phased Dicke states are also discussed in detail.Comment: accepted for publication on EPJ
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