19,042 research outputs found
Did working families' tax credit work? The final evaluation of the impact of in-work support on parents' labour supply and take-up behaviour in the UK
With micro-data from before and after a major reform in 1999 to the structure and form of in-work transfers in the UK, this paper uses a structural model of labour supply and programme participation to evaluate the labour market impact of Working Families' Tax Credit (WFTC). Estimates suggest that by 2002, WFTC had increased labour supply of lone mothers by around 5.11 percentage points, slightly reduced labour supply of mothers in couples by 0.57 percentage points, and increased the labour supply of fathers in couples by 0.75 percentage points, compared with the benefit that preceded it, called Family Credit. In aggregate, these changes are equivalent to a fall of 99,000 in the number of workless families with children, and a net increase in labour market participation of 81,000 workers. However, contemporaneous tax and benefit reforms acted to reduce the labour supply of parents, and so the overall impact of tax and benefit changes introduced since 1999 is lower than stated above. Participating in Family Credit, the UK's in-work programme before October 1999, conferred a utility loss as well as a utility gain from the extra income, but we find this utility cost of participation to be lower in the final year of WFTC than it was in the last year of Family Credit for lone mothers, and no different for individuals in couples: this in itself induced more lone mothers to work
Did Working Families' Tax Credit work? Analysing the impact of in-work support on labour supply and programme participation
With micro-data from before and after a major reform in 1999 to the structure and form of in-work transfers in the UK, this paper uses a structural model of labour supply and programme participation to show the impact of a reform to in-work support (Working Families' Tax Credit) on both labour supply and programme participation (or take-up). Estimates suggest that the changes in in-work incomes through the introduction of WFTC increased labour supply of lone mothers by around 4.6 percentage points, slightly reduced labour supply of mothers in couples by 0.2 percentage points, and increased the labour supply of fathers in couples by 0.8 percentage points, equivalent to a net increase in participation of 94,000 workers. Participating in Family Credit, the UK's in-work programme before October 1999, conferred a utility loss as well as a utility gain from the extra income, but we find this utility cost of participation to be lower under WFTC
First Principles Simulations of Boron Diffusion in Graphite
Boron strongly modifies electronic and diffusion properties of graphite. We report the first ab initio study of boron interaction with the point defects in graphite, which includes structures, thermodynamics, and diffusion. A number of possible diffusion mechanisms of boron in graphite are suggested. We conclude that boron diffuses in graphite by a kick-out mechanism. This mechanism explains the common activation energy, but large magnitude difference, for the rate of boron diffusion parallel and perpendicular to the basal plane. Ā© 2007 The American Physical Society
Hyperonic crystallization in hadronic matter
Published in Hadrons, Nuclei and Applications, World Scientific, Singapore,
Proc.of the Conference Bologna2000. Structure of the Nucleus at the Dawn of the
Century, G. Bonsignori, M. Bruno, A. Ventura, D. Vretenar Editors, pag. 319.Comment: 4 pages, 2figure
Quantum correlations versus Multisimultaneity: an experimental test
Multisimultaneity is a causal model of relativistic quantum physics which
assigns a real time ordering to any set of events, much in the spirit of the
pilot-wave picture. Contrary to standard quantum mechanics, it predicts a
disappearance of the correlations in a Bell-type experiment when both analysers
are in relative motion such that, each one in its own inertial reference frame,
is first to select the output of the photons. We tested this prediction using
acousto-optic modulators as moving beam-splitters and interferometers separated
by 55 m. We didn't observe any disappearance of the correlations, thus refuting
Multisimultaneity.Comment: 4 pages, 3 figures, RevTex 4 versio
Magnetic Structure of Hydrogen Induced Defects on Graphene
Using density functional theory (DFT), Hartree-Fock, exact diagonalization,
and numerical renormalization group methods we study the electronic structure
of diluted hydrogen atoms chemisorbed on graphene. A comparison between DFT and
Hartree-Fock calculations allows us to identify the main characteristics of the
magnetic structure of the defect. We use this information to formulate an
Anderson-Hubbard model that captures the main physical ingredients of the
system, while still allowing a rigorous treatment of the electronic
correlations. We find that the large hydrogen-carbon hybridization puts the
structure of the defect half-way between the one corresponding to an adatom
weakly coupled to pristine graphene and a carbon vacancy. The impurity's
magnetic moment leaks into the graphene layer where the electronic correlations
on the C atoms play an important role in stabilizing the magnetic solution.
Finally, we discuss the implications for the Kondo effect.Comment: 10 pages, 10 fig
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