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Context. Evaporating rocky exoplanets, such as KIC 12557548b, eject large amounts of dust, which can trail the planet in a comet-like tail. When such objects occult their host star, the resulting transit signal contains information about the dust in the tail. Aims. We aim to use the detailed shape of the Kepler light curve of KIC 12557548b to constrain the size and composition of the dust grains that make up the tail, as well as the mass loss rate of the planet. Methods. Using a self-consistent numerical model of the dust dynamics and sublimation, we calculated the shape of the tail by following dust grains from their ejection from the planet to their destruction due to sublimation. From this dust cloud shape, we generated synthetic light curves (incorporating the effects of extinction and angle-dependent scattering), which were then compared with the phase-folded Kepler light curve. We explored the free-parameter space thoroughly using a Markov chain Monte Carlo method. Results. Our physics-based model is capable of reproducing the observed light curve in detail. Good fits are found for initial grain sizes between 0.2 and 5.6 µm and dust mass loss rates of 0.6 to 15.6 M ⊕ Gyr −1 (2σ ranges). We find that only certain combinations of material parameters yield the correct tail length. These constraints are consistent with dust made of corundum (Al 2 O 3 ), but do not agree with a range of carbonaceous, silicate, or iron compositions. Conclusions. Using a detailed, physically motivated model, it is possible to constrain the composition of the dust in the tails of evaporating rocky exoplanets. This provides a unique opportunity to probe to interior composition of the smallest known exoplanets.

Cultural heritage is a potentially important determinant of international tourism flows. Apart from being an enrichment for both individuals and communities and an opportunity for different cultures to meet, tourism also represents a significant industry for European economies. We empirically investigate the impact of the endowment of tangible cultural heritage on tourism attractiveness of European regions. We measure material forms of cultural heritage both as regional density of locally defined monuments, cultural landscapes and museums, and as number of cultural sites listed in the UNESCO World Heritage Sites international programme. Using a Bayesian multilevel gravity model, we find that UNESCO cultural World Heritage Sites are associated with an increase of 6,000 (one site) to 60,000 (eight sites) international tourists from each European country to an average European region. On the other hand, regionally or nationally defined tangible forms of heritage play a more limited role as pull‐factors for international tourism. Moreover, we show that the presence of UNESCO sites reduces the distance decay effect. International tourists are willing to travel longer distance if a destination is endowed with UNESCO cultural World Heritage Sites.

We use data on Mexican and Chinese immigrants in the US to calculate the average marginal effects of residential and occupational segregation on immigrants' ability to speak English, and similarly the effects of English fluency of family members. Our results confirm that residential segregation is generally inversely related to English language proficiency of immigrants, except for skilled Chinese immigrants. Allowing for occupational fixed effects, the minority population share at the place of work is relevant for proficiency in English among skilled Chinese, but not for Mexicans and unskilled Chinese. We also find that the presence of English‐speaking adults in the household increases the probability of immigrants' proficiency in English.

There is an increasing awareness of the potentials of nonlinear modeling in regional science. This can be explained partly by the recognition of the limitations of conventional equilibrium models in complex situations, and also by the easy availability and accessibility of sophisticated computational techniques. Among the class of nonlinear models, dynamic variants based on, for example, chaos theory stand out as an interesting approach. However, the operational significance of such approaches is still rather limited and a rigorous statistical-econometric treatment of nonlinear dynamic modeling experiments is lacking. Against this background this paper is concerned with a methodological and empirical analysis of a general misspecification test for spatial regression models that is expected to have power against nonlinearity, spatial dependence, and heteroskedasticity. The paper seeks to break new research ground by linking the classical diagnostic tools developed in spatial econometrics to a misspecification test derived directly from chaos theory-the BDS test, developed by Brock, Dechert, and Scheinkman (1987). A spatial variant of the BDS test is introduced and applied in the context of two examples of spatial process models, one of which is concerned with the spatial distribution of regional investments in The Netherlands, the other with spatial crime patterns in Columbus, Ohio. Copyright 2001 BlackwellPublishers

Immigration and multiculturalism are at the heart of modern western societies. The issue of language acquisition of immigrants is intrinsically linked to immigration. We formally link language acquisition of immigrants to the relative size of the immigrant stock, employing a microeconomic trading framework. Our model allows for spatial interaction going beyond the immigrant's area of residence, and explicitly incorporates spatial segregation. In addition, behavioral differences of immigrants with respect to their level of assimilation into the host country as well as differences in networking within their own ethnic community are accounted for. We test our model for four non-western immigrant groups in the Netherlands using two different spatial scale levels. The empirical results reveal that there is only ambiguous support for the inverse relationship between size of the immigrant community and language acquisition or language proficiency in The Netherlands. We find instead, that there is strong support for language acquisition and understanding being positively influenced by assimilation to the host country's culture.