1,203 research outputs found

    The abortion-crime link: evidence from England and Wales

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    We use panel data from 1983 to 1997 for the 42 police force areas in England and Wales to test the hypothesis that legalizing abortion contributes to lower crime rates. We provide an advance on previous work by focusing on the impact of possible endogeneity of effective abortion rates with respect to crime. Our use of U.K. data allows us to exploit regional differences in the provision of free abortions to identify abortion rates. When we use a similar model and estimation methodology, we are able to replicate the negative association between abortion rates and reported crime found by Donohue and Levitt for the U.S. However, when we allow for the potential endogeneity of effective abortion rates with respect to crime, we find no clear connection between the two.

    Elastic and Raman scattering of 9.0 and 11.4 MeV photons from Au, Dy and In

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    Monoenergetic photons between 8.8 and 11.4 MeV were scattered elastically and in elastically (Raman) from natural targets of Au, Dy and In.15 new cross sections were measured. Evidence is presented for a slight deformation in the 197Au nucleus, generally believed to be spherical. It is predicted, on the basis of these measurements, that the Giant Dipole Resonance of Dy is very similar to that of 160Gd. A narrow isolated resonance at 9.0 MeV is observed in In.Comment: 31 pages, 11 figure

    Estimates in Beurling--Helson type theorems. Multidimensional case

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    We consider the spaces Ap(Tm)A_p(\mathbb T^m) of functions ff on the mm -dimensional torus Tm\mathbb T^m such that the sequence of the Fourier coefficients f^={f^(k), k∈Zm}\hat{f}=\{\hat{f}(k), ~k \in \mathbb Z^m\} belongs to lp(Zm), 1≀p<2l^p(\mathbb Z^m), ~1\leq p<2. The norm on Ap(Tm)A_p(\mathbb T^m) is defined by ∄f∄Ap(Tm)=∄f^∄lp(Zm)\|f\|_{A_p(\mathbb T^m)}=\|\hat{f}\|_{l^p(\mathbb Z^m)}. We study the rate of growth of the norms ∄eiλφ∄Ap(Tm)\|e^{i\lambda\varphi}\|_{A_p(\mathbb T^m)} as âˆŁÎ»âˆŁâ†’âˆž, λ∈R,|\lambda|\rightarrow \infty, ~\lambda\in\mathbb R, for C1C^1 -smooth real functions φ\varphi on Tm\mathbb T^m (the one-dimensional case was investigated by the author earlier). The lower estimates that we obtain have direct analogues for the spaces Ap(Rm)A_p(\mathbb R^m)

    Observational evidence of the formation of cyanopolyynes in CRL618 through the polimerization of HCN

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    The abundance ratio of consecutive members of the cyanopolyynes family has been explored in CRL618 using data acquired in a complete line survey covering the frequency range 81-356 GHz. The Jup range explored for the different molecules is the following: 1 to 4 for HCN and HNC, 9 to 39 for HC3N, 31 to 133 for HC5N, and 72 to 85 for HC7N (not detected beyond Jup=85). The lowest vibrationally excited state of HC7N (nu_15 at 62 cm^-1) has been tentatively detected. Data analysis has been performed by extending our previous geometrical and radiative transfer model of the slowly expanding envelope (SEE) surrounding the compact central continuum source of CRL 618, that was established from the study of rotational lines in several vibrationally excited states of HC_3N. The new lines analyzed here require to model the high velocity wind (HVW) component and the colder circumstellar gas, remnant of the AGB phase of CRL618. The derived HC3N/HC5N and HC5N/HC7N abundance ratios from this set of uniformly calibrated lines are between 3 and 6 in the different regions, similar to standard values in the CSM and ISM, and consistent with previous estimates obtained from ISO observations and chemical models. However, the abundance ratios of HC3N, HC5N and HC7N with respect to HCN are at least two orders of magnitude larger than those typical for AGB C-rich stars, such as IRC+10216. This fact indicates that, in the short transition toward the Planetary Nebula phase, HCN is quickly reprocessed into longer cyanopolyyne chains. A similar behavior was previously found in this object for the polyacetylenic chains (C(2n)H2).Comment: 8 figures, accepted in ApJ main journa

    A new method for calculation of traces of Dirac Îł\gamma-matrices in Minkowski space

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    This paper presents some relations for orthonormal bases in the Minkowski space and isotropic tetrads constructed from the vectors of these bases. As an example of an application of the obtained formulae, in particular recursion relations, a new method is proposed to calculate traces of Dirac Îł\gamma-matrices in the Minkowski space. Compared to the classical algorithms, the new method results in more compact expressions for the traces. Specifically, it may be easily implemented as a simple yet efficient computer algorithm.Comment: 13 pages, LaTeX2E, version to appear in Nuclear Physics

    Mass loss rates of a sample of irregular and semiregular M-type AGB-variables

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    We have determined mass loss rates and gas expansion velocities for a sample of 69 M-type irregular (IRV; 22 objects) and semiregular (SRV; 47 objects) AGB-variables using a radiative transfer code to model their circumstellar CO radio line emission. We believe that this sample is representative for the mass losing stars of this type. The (molecular hydrogen) mass loss rate distribution has a median value of 2.0E-7 solar masses per year. M-type IRVs and SRVs with a mass loss rate in excess of 5E-7 solar masses per year must be very rare, and among these mass losing stars the number of sources with mass loss rates below a few 10E-8 solar masses per year must be small. We find no significant difference between the IRVs and the SRVs in terms of their mass loss characteristics. Among the SRVs the mass loss rate shows no dependence on the period. Likewise the mass loss rate shows no correlation with the stellar temperature. The gas expansion velocity distribution has a median of 7.0 km/s. The mass loss rate and the gas expansion velocity correlate well, a result in line with theoretical predictions for an optically thin, dust-driven wind. In general, the model produces line profiles which acceptably fit the observed ones. We have compared the results of this M-star sample with a similar C-star sample analysed in the same way. The mass loss rate characteristics are very similar for the two samples. On the contrary, the gas expansion velocity distributions are clearly different. In particular, the number of low-velocity sources is much higher in the M-star sample. We found no example of the sharply double-peaked CO line profile, which is evidence of a large, detached CO-shell, among the M-stars. About 10% of the C-stars show this phenomenon.Comment: 16 pages, 11 figures, accepted by A&

    Doing good by doing nothing? The role of social norms in explaining default effects in altruistic contexts

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    We explore whether the known preference for default options in choice contexts—default effects—occur in altruistic contexts and the extent to which this can be explained through appeal to social norms. In four experiments, we found that (i) participants were more likely to donate money to charity when this was the default option in an altruistic choice context; (ii) participants perceived the default option to be the socially normative option; (iii) perceptions of social norms mediated the relationship between default status and charitable donations; and (iv) a transfer effect, whereby participants translated social norms they inferred from the default option in one domain into behavior in a second, related domain. Theoretically, our analysis situates default effects within a comprehensive body of social psychological research concerning social norms and the attitude‐behavior relationship, providing novel empirical predictions. Practically, these findings highlight that the way donation policies are framed can have an important impact on donation behavior: in our third study, we found that 81% donated half of their earnings for taking part in the experiment to charity when this was the default option, compared with only 19% when keeping the money was the default. Our work suggests that making use of default effects could be an effective tool to increase altruistic behavior without compromising freedo

    The geometry of fractal percolation

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    A well studied family of random fractals called fractal percolation is discussed. We focus on the projections of fractal percolation on the plane. Our goal is to present stronger versions of the classical Marstrand theorem, valid for almost every realization of fractal percolation. The extensions go in three directions: {itemize} the statements work for all directions, not almost all, the statements are true for more general projections, for example radial projections onto a circle, in the case dim⁥H>1\dim_H >1, each projection has not only positive Lebesgue measure but also has nonempty interior. {itemize}Comment: Survey submitted for AFRT2012 conferenc
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