Dots to boxes: Do the size and shape of spatial units jeopardize economic geography estimations?

This paper evaluates, in the context of economic geography estimates, the magnitude of the distortions arising from the choice of zoning system, which is also known as the Modifiable Areal Unit Problem (MAUP). We consider three standard economic geography exercises (the analysis of spatial concentration, agglomeration economies, and trade determinants), using various French zoning systems differentiated according to the size and shape of spatial units, which are the two main determinants of the MAUP. While size matters a little, shape does so much less. Both dimensions seem to be of secondary importance compared to specification issues.MAUP ; concentration ;agglomeration ;wage equations ;gravity

DOTS TO BOXES: DO THE SIZE AND SHAPE OF SPATIAL UNITS JEOPARDIZE ECONOMIC GEOGRAPHY ESTIMATIONS?

This paper evaluates, in the context of economic geography estimates, the magnitude of the distortions arising from the choice of zoning system, which is also known as the Modifiable Areal Unit Problem (MAUP). We consider three standard economic geography exercises (the analysis of spatial concentration, agglomeration economies, and trade determinants), using various French zoning systems differentiated according to the size and shape of spatial units, which are the two main determinants of the MAUP. While size matters a little, shape does so much less. Both dimensions seem to be of secondary importance compared to specification issues.MAUP, concentration, agglomeration, wage equations, gravity

Product complexity, quality of institutions and the pro-trade effect of immigrants

The paper assesses the trade-creating impact of foreign-born residents on the international imports and exports of the French regions where they are settled. The pro-trade effect of immigrants is investigated along two intertwined dimensions: the complexity of traded goods and the quality of institutions in partner countries. The trade-enhancing impact of immigrants is, on average, more salient when they come from a country with weak institutions. However, this positive impact is especially large on the imports of simple products. When we turn to complex goods, for which the information channel conveyed by immigrants is the most valuable, immigration enhances imports regardless of the quality of institutions in the partner country. Regarding exports, immigrants substitute for weak institutions on both simple and complex goods.trade ; immigration ; quality of institutions ; product complexity ; gravity

PRODUCT COMPLEXITY, QUALITY OF INSTITUTIONS AND THE PRO-TRADE EFFECT OF IMMIGRANTS

The paper assesses the trade-creating impact of foreign-born residents on the international imports and exports of the French regions where they are settled. The pro-trade effect of immigrants is investigated along two intertwined dimensions: the complexity of traded goods and the quality of institutions in partner countries. The trade-enhancing impact of immigrants is, on average, more salient when they come from a country with weak institutions. However, this positive impact is especially large on the imports of simple products. When we turn to complex goods, for which the information channel conveyed by immigrants is the most valuable, immigration enhances imports regardless of the quality of institutions in the partner country. Regarding exports, immigrants substitute for weak institutions on both simple and complex goods.MAUP; concentration; agglomeration; wage equations; gravity

Agglomeration Economies and Business Productivity: an Estimate on French Individual Data

The persistent spatial concentration of certain activity sectors is hard to explain without admitting the existence of agglomeration economies. Using three administrative databases on French corporate accounts and employment, we assess the impact on these enterprises total factor productivity of urbanization externalities, i.e., those created from total size, accessibility, and industrial diversity of the location area, and localization externalities, which relate to the level of specialization of an activity area. We find a significant impact of an areas accessibility to the rest of the national market as well of the density of its economic fabric on average productivity. Specialization has powerful local effects, suggesting the existence of localization externalities. Firms are more productive in areas where their industry is relatively more concentrated. The diversity of local economic activities appears to have little influence. Similarly, the degree of local competition does not, on average, affect the productivity of firms in a cluster.Enterprises total factor productivity, Agglomeration, Urbanization Externalities, Localization Externalities

Can Tax Breaks Beat Geography? Lessons from the French Enterprise Zone Experience

This paper providesempirical support to the intuitive statement that urban geography matters to the success or failure of place-based public policies, using the French enterprise zone program as a case study. According to the few existing evaluations, this program has only had a small positive average impact on firm and job creation rates. In addition, this impact was shown to be strongly heterogeneous across the treated neighborhoods may account for part of these results. We estimate a series of augmented difference-in-differences models in which we interact the treatment indicator with a series of original indicators of spatial isolation, wich account for severance, peripherality and disconnection to transportation networks within the urban area. Results indicate that isolation does matter to explain spatial differentials in job creation and firm settlement rates across enterprise zones: only accessible neighborhoods were able to draw benefits from tax breaks and social exemptions. moreover, whereas the program mostly worked through a displacement effect on pre-existing firms, we show that urban geography was a clear determinant of the decision to create new firms from scratch

Product complexity, quality of institutions and the pro-trade effect of immigrants

The paper assesses the trade-creating impact of foreign-born residents on the international imports and exports of the French regions where they are settled. The pro-trade effect of immigrants is investigated along two intertwined dimensions: the complexity of traded goods and the quality of institutions in partner countries. The trade-enhancing impact of immigrants is, on average, more salient when they come from a country with weak institutions. However, this positive impact is especially large on the imports of simple products. When we turn to complex goods, for which the information channel conveyed by immigrants is the most valuable, immigration enhances imports regardless of the quality of institutions in the partner country. Regarding exports, immigrants substitute for weak institutions on both simple and complex goods.Cet article évalue le rôle positif joué par les résidents français nés à l'étranger sur le commerce international du département d'accueil avec leur pays d'origine. En moyenne, les immigrés facilitent d'autant plus les échanges avec leur pays d'origine que ce dernier dispose de mauvaises institutions (règles de non droit). Cette interaction est particulièrement visible pour les importations de produits homogènes. L'importation des biens différenciés, dont l'échange requiert plus d'information, est favorisée par les immigrés indépendamment de la qualité des institutions du pays d'origine. En ce qui concerne les exportations, les migrants pallient la faiblesse des institutions, aussi bien pour le commerce des biens homogènes que pour celui des produits différenciés

Product Complexity, Quality of Institutions and the Pro-Trade Effect of Immigrants

The paper assesses the trade-creating impact of foreign-born residents on the international imports and exports of the French regions where they are settled. The protrade effect of immigrants is investigated along two intertwined dimensions: the complexity of traded goods and the quality of institutions in partner countries. The trade-enhancing impact of immigrants is, on average, more salient when they come from a country with weak institutions. However, this positive impact is especially large on the imports of simple products. When we turn to complex goods, for which the information channel conveyed by immigrants is the most valuable, immigration enhances imports regardless of the quality of institutions in the partner country. Regarding exports, immigrants substitute for weak institutions on both simple and complex goods

Mapping the cellular electrophysiology of rat sympathetic preganglionic neurones to their roles in cardiorespiratory reflex integration:A whole cell recording study in situ

Sympathetic preganglionic neurones (SPNs) convey sympathetic activity flowing from the CNS to the periphery to reach the target organs. Although previous in vivo and in vitro cell recording studies have explored their electrophysiological characteristics, it has not been possible to relate these characteristics to their roles in cardiorespiratory reflex integration. We used the working heart–brainstem preparation to make whole cell patch clamp recordings from T3–4 SPNs (n = 98). These SPNs were classified by their distinct responses to activation of the peripheral chemoreflex, diving response and arterial baroreflex, allowing the discrimination of muscle vasoconstrictor-like (MVC(like), 39%) from cutaneous vasoconstrictor-like (CVC(like), 28%) SPNs. The MVC(like) SPNs have higher baseline firing frequencies (2.52 ± 0.33 Hz vs. CVC(like) 1.34 ± 0.17 Hz, P = 0.007). The CVC(like) have longer after-hyperpolarisations (314 ± 36 ms vs. MVC(like) 191 ± 13 ms, P < 0.001) and lower input resistance (346 ± 49  MΩ vs. MVC(like) 496 ± 41 MΩ, P < 0.05). MVC(like) firing was respiratory-modulated with peak discharge in the late inspiratory/early expiratory phase and this activity was generated by both a tonic and respiratory-modulated barrage of synaptic events that were blocked by intrathecal kynurenate. In contrast, the activity of CVC(like) SPNs was underpinned by rhythmical membrane potential oscillations suggestive of gap junctional coupling. Thus, we have related the intrinsic electrophysiological properties of two classes of SPNs in situ to their roles in cardiorespiratory reflex integration and have shown that they deploy different cellular mechanisms that are likely to influence how they integrate and shape the distinctive sympathetic outputs

Modelling the vascular response to sympathetic postganglionic nerve activity

AbstractThis paper explores the influence of burst properties of the sympathetic nervous system on arterial contractility. Specifically, a mathematical model is constructed of the pathway from action potential generation in a sympathetic postganglionic neurone to contraction of an arterial smooth muscle cell. The differential equation model is a synthesis of models of the individual physiological processes, and is shown to be consistent with physiological data.The model is found to be unresponsive to tonic (regular) stimulation at typical frequencies recorded in sympathetic efferents. However, when stimulated at the same average frequency, but with repetitive respiratory-modulated burst patterns, it produces marked contractions. Moreover, the contractile force produced is found to be highly dependent on the number of spikes in each burst. In particular, when the model is driven by preganglionic spike trains recorded from wild-type and spontaneously hypertensive rats (which have increased spiking during each burst) the contractile force was found to be 10-fold greater in the hypertensive case. An explanation is provided in terms of the summative increased release of noradrenaline. Furthermore, the results suggest the marked effect that hypertensive spike trains had on smooth muscle cell tone can provide a significant contribution to the pathology of hypertension