1,551 research outputs found
Residential segregation: The role of inequality and housing subsidies
No full textResidential segregation is a key public policy issue that is driven by economic factors on the one side, and individual attitudes towards ethnic diversity on the other side. We assume a modeling framework that consists of a population of two ethnic groups, a rental market for each neighborhood, and household's utility which depends on consumption and housing. Accounting for income disparities and heterogeneous preferences for living in ethnically diverse neighborhoods, we examine the residential segregation patterns that occur when households make their neighborhood choice by taking economic and diversity related aspects into account. The investigation reveals that ethnic income disparities and heterogeneous preferences are antagonistic forces such that a certain level of income stratification is the price for residential integration. In light of these findings, we discuss to which extent and under which conditions housing subsidy policies can favor residential integration
R&D location in dynamic industry environments
No full textColombo L, Dawid H, Harting P. R&D location in dynamic industry environments. Journal of Economic Geography. 2024;24(1):41-62.**Abstract**
We study firms’ optimal R&D location strategies in a dynamic industry model with competition in product quality. In light of potential future inwards and outwards spillovers firms make their location choices relying on heuristic strategies that are based on the expected present values associated with alternative location patterns. Using a simulation analysis, we show how the strategies of innovators and imitators differ and how they depend on whether firms operate in strongly or weakly innovative industry environments. We also characterize how firms’ location choices should account for the innovativeness of the competitors active in a location
Sulawesidrobia carsonae Haase & Rintelen & Harting & Marwoto & Glaubrecht 2023, sp. nov.
No full textSulawesidrobia carsonae sp. nov. urn:lsid:zoobank.org:act: 1E37CB23-9233-4A75-810F-C6109B54C098 Figs 2B, 3C–D, 4A–B, 5B, 6D, 7C–D, 8C–D Diagnosis The new species has a small, short-conical shell with a unique protoconch structure where the fine pits are distally rearranged as irregular longitudinal striae. It is the only short-conical species combining a single large inner denticle on the lateral radular tooth and a penis with broad base and slender, parallelsided distal end. A single position of type 1 characterizes this new species (Table 3). Etymology Sulawesidrobia carsonae sp. nov. is dedicated to the American zoologist and writer Rachel Carson (1907–1964) whose influential 1962 book Silent Spring had a lasting effect on the global environmental movement. Material examined Holotype (Fig. 4C) INDONESIA • Sulawesi, Lake Matano, S-shore, Inco boat house, below guest house, on rocks; 02°30.696′ S, 121°20.352′ E; Sep. 2003; Glaubrecht, von Rintelen and Zitzler leg.; MZB Gst. 12118. Paratypes (Figs 4D, 5B–C) INDONESIA • 11 specs; same collection data as for holotype; MZB Gst. 12119 • 10 specs; same collection data as for holotype; ZMB 107079. Description SHELL (Figs 2B, 3C, 4A–B). Short-conical, sutures very shallow, about 1.5 times as high as wide, shell and priostracum light brown; protoconch initially with fine pits rearranging to irregular longitudinal striae and ca 0.75 whorls; entire shell with 3.75 to 4.125 whorls, teleoconch without structure apart from growth lines; umbilicus a narrow slit; aperture orthocline, only slightly higher than wide. OPERCULUM. Very light yellow and thin, paucispiral, nucleus eccentric. EXTERNAL FEATURES. Epidermis entirely black with the exception of mantle rim and areas over distal genital glands and stomach; tentacles with ciliated field (Fig. 5B). MANTLE CAVITY (N = 4). 13–16 ctenidial filaments; osphradium elongate lying centrally under ctenidium along 75% of its length. DIGESTIVE SYSTEM. The radula has the formula R 5 1 5/2-3 2-3, L 1-2 1 5-6, M1 18-24, M2 23-27, denticles of central tooth pointed and basally fused, two rhachidial basal cusps were only rarely observed, the same holds for a second small inner denticle on the lateral tooth, mostly there is only a single, very large one (Fig. 6D); stomach without caecum, black; intestine follows pallial genital glands, in females closer than in males. FEMALE GENITALIA (N = 2; Fig. 7C–D). Ovary starts 1–1.25 whorls below apex, comprises 0.5–0.7 whorls and covers the posterior stomach chamber; renal oviduct first coiling 180° clockwise, then 270° counterclockwise; no receptaculum seminis; bursa copulatrix spherical, behind albumen gland, bursal duct entering anteriorly; albumen gland milky-white, capsule gland bipartite, opaque-white. MALE GENITALIA (N = 2; Fig. 8C–D). Testis a lobate sac, starts 0.5–0.75 whorls below apex, comprises ca 1.25 whorls, anteriorly overlapping stomach; vesicula seminalis coils along anterior quarter of testis; proximal and distal vasa deferentia insert close to middle of kidney-shaped prostate; penis with broad base and slender, parallel-sided distal end. Remarks There is only one other short-conical congener with a single large inner denticle on the lateral radular tooth, viz S. crutzeni sp. nov. The latter is 1.6 times larger and has a penis with very broad base and continuously tapering long distal end, though. In addition, it lacks a bursa copulatrix (see below). Sulawesidrobia carsonae sp. nov. was highly supported in the phylogenetic trees (Figs 9–10,Supp. file 1) although it had only a single diagnostic alignment position of type 1 (Table 3).Published as part of Haase, Martin, Rintelen, Thomas von, Harting, Britta, Marwoto, Ristiyanti & Glaubrecht, Matthias, 2023, New species from a ' lost world': Sulawesidrobia (Caenogastropoda, Tateidae) from ancient Lake Matano, Sulawesi, Indonesia, pp. 77-103 in European Journal of Taxonomy 864 (1) on pages 84-88, DOI: 10.5852/ejt.2023.864.2089, http://zenodo.org/record/784163
R&D Location Strategies
No full textColombo L, Dawid H, Harting P. R&D Location Strategies. Universität Bielefeld Working Papers in Economics and Management. Vol 10-2019. Bielefeld: Bielefeld University, Department of Business Administration and Economics; 2019.We examine the profitability of different R&D location strategies of firms in a
dynamic industry model. Firms engage in imitative and innovative activities in
order to improve their products' quality, which determines their competitiveness.
When choosing the set of locations in which to operate firms face a fundamental
trade-off: co-locating with competitors' generates opportunities to improve product
quality through imitation, but at the same time it increases the risk of losing
one's competitive edge through outgoing spillovers. Being unable to fully predict
competitors' moves, in making location choices firms rely on heuristics based on
the expected present values associated with alternative location patterns. In a
positive perspective, our model replicates key stylized facts highlighted in the pertinent
empirical literature. On normative ground, we identify industry scenarios in
which a firm should enter (not enter) a location even if the expected present value
of doing so is negative (positive). Our key contribution is to provide a taxonomy
of suitable firm location strategies depending on firm type and industry characteristics
in a dynamic environment with endogenous cluster formation
Governance structure, technical change, and industry competition
No full textWe develop a model to study the impact of corporate governance on the investment decisions of firms and competition in an industry populated by publicly owned firms. A bargaining process between firm's stakeholders determines the optimal allocation of financial resources between real investments in R&D and financial investments in shares buybacks. We characterize the relation between governance and investment strategy and we study how different governance structures shape technical progress and competition over the industrial life cycle. Numerical simulations of a calibrated set-up of the model show that pooling together industries characterized by heterogeneous governance structures generate the well-documented inverted-U shaped relation between competition and innovation
Sulawesidrobia ehrlichi Haase & Rintelen & Harting & Marwoto & Glaubrecht 2023, sp. nov.
No full textSulawesidrobia ehrlichi sp. nov. urn:lsid:zoobank.org:act: 329722EB-1CD2-4441-AFC1-4C69C9203758 Figs 2C, 3E–F, 4C–D, 6E, 7E–F, 8E–F Diagnosis This new species is a larger conical Sulawesidrobia with a characteristic radula in which the denticles of the central tooth are fused, the central denticles of both central and lateral teeth have rounded tips, and the denticles on the lateral teeth are comparatively large and reduced in number. It is the only larger conical species with a broad based penis and slender, parallel-sided distal end. There are three diagnostic positions, two of type 1 and one of type 3 (Table 3). Etymology Named in honor for the American biologist Paul Ralph Ehrlich (born 1932), best known for his early warnings of the devastating effects of overpopulation depleting natural resources in his 1968 book The Population Bomb, coauthored with his wife Anne. Material examined Holotype (Fig. 2C) INDONESIA • Sulawesi, Lake Matano, S shore, on rocks and macrophytes; 02°28.461′ S, 121°15.591′ E; 24 Jul. 2004; von Rintelen and Zitzler leg.; MZB Gst. 12120. Paratypes (Fig. 3E–F) INDONESIA • 70 specs; same collection data as for holotype; MZB Gst. 12121 • 69 specs; same collection data as for holotype; ZMB 107095. Description SHELL (Figs 2C, 3E–F, 4C–D). Short-conical, sutures very shallow, about 1.6 times as high as wide, shell and periostracum light brown; protoconch with fine pits and ca 0.8 whorls; entire shell with 4.125 to 4.750 whorls, teleoconch without structure apart from growth lines; umbilicus a narrow slit; aperture orthocline, only slightly higher than wide. OPERCULUM. Light yellow and thin, paucispiral, nucleus eccentric. EXTERNAL FEATURES. Epidermis entirely black with the exception of mantle rim and areas over distal genital glands and stomach; tentacles with ciliated field. MANTLE CAVITY (N = 4). 17–20 ctenidial filaments; osphradium elongate lying under posterior two thirds of ctenidium. DIGESTIVE SYSTEM. The radula has the formula R 4-5 1 4-5/3 3, L 2 1 2-4, M1 10-12, M2 18-24, denticles of central tooth basally fused, central denticles of both central and lateral teeth with rounded tip, denticles of lateral tooth comparatively large but reduced in number, innermost cusp of lateral tooth may be very small (Fig. 6E); stomach black without caecum; intestine follows pallial genital glands, in females closer than in males. FEMALE GENITALIA (N = 2; Fig. 7E–F). Ovary starts 1–1.25 whorls below apex, comprises 0.5 whorls and covers the stomach chambers; renal oviduct first coiling 180° clockwise, then 270° counter-clockwise; no receptaculum seminis; bursa copulatrix egg-shaped behind albumen gland, bursal duct entering anteriorly; albumen gland milky-white, capsule gland with smaller anterior white and larger posterior yellow portion. MALE GENITALIA (N = 2). Testis lobate, starts 0.75–1 whorls below apex, comprises ca 1.25 whorls, covers stomach chambers; vesicula seminalis coils along anterior half of testis; vasa deferentia insert close to middle of kidney-shaped prostate; penis with slightly broadened base and long, slender, parallel-sided distal end (Fig. 8E–F). Remarks The unresolved relationships with S. crutzeni sp. nov., possibly due to incomplete lineage sorting, suggest a close relationship (Figs 9–10, Supp. file 1) reflected also by the low number of diagnostic alignment positions, two of which were of type 1 and one of type 3 (Table 3). Yet, radular and genital features clearly indicate that both are distinct. Lateral and both marginal teeth have considerably less denticles in S. wilsoni sp nov. than in S. crutzeni. The latter lacks a bursa copulatrix and its penis is broad-based with a long, tapering distal end (see below). Sulawesidrobia dinersteini sp. nov. shares the lateral tooth morphology seen in this species (see below).Published as part of Haase, Martin, Rintelen, Thomas von, Harting, Britta, Marwoto, Ristiyanti & Glaubrecht, Matthias, 2023, New species from a ' lost world': Sulawesidrobia (Caenogastropoda, Tateidae) from ancient Lake Matano, Sulawesi, Indonesia, pp. 77-103 in European Journal of Taxonomy 864 (1) on pages 88-91, DOI: 10.5852/ejt.2023.864.2089, http://zenodo.org/record/784163
Residential segregation: The role of inequality and housing subsidies
No full textHarting P, Radi D. Residential segregation: The role of inequality and housing subsidies. Journal of Economic Behavior & Organization. 2020;178:801-819.Residential segregation is a key public policy issue that is driven by economic factors on the one side, and individual attitudes towards ethnic diversity on the other side. We assume a modeling framework that consists of a population of two ethnic groups, a rental market for each neighborhood, and household's utility which depends on consumption and housing. Accounting for income disparities and heterogeneous preferences for living in ethnically diverse neighborhoods, we examine the residential segregation patterns that occur when households make their neighborhood choice by taking economic and diversity related aspects into account. The investigation reveals that ethnic income disparities and heterogeneous preferences are antagonistic forces such that a certain level of income stratification is the price for residential integration. In light of these findings, we discuss to which extent and under which conditions housing subsidy policies can favor residential integration. (c) 2020 Elsevier B.V. All rights reserved
Fig. 2. Holotypes. A in New species from a 'lost world': Sulawesidrobia (Caenogastropoda, Tateidae) from ancient Lake Matano, Sulawesi, Indonesia
No full textFig. 2. Holotypes. A. Sulawesidrobia wilsoni sp. nov. (MZB Gst. 12116). B. S. carsonae sp. nov. (MZB Gst. 12118). C. S. ehrlichi sp. nov. (MZB Gst. 12120). D. S. crutzeni sp. nov. (MZB Gst. 12122). E. S. dinersteini sp. nov. (MZB Gst. 12124). Scale bar = 1 mm.Published as part of Haase, Martin, Rintelen, Thomas von, Harting, Britta, Marwoto, Ristiyanti & Glaubrecht, Matthias, 2023, New species from a 'lost world': Sulawesidrobia (Caenogastropoda, Tateidae) from ancient Lake Matano, Sulawesi, Indonesia, pp. 77-103 in European Journal of Taxonomy 864 (1) on page 84, DOI: 10.5852/ejt.2023.864.2089, http://zenodo.org/record/784163
Simulation of neutral gas flow in the JET sub-divertor
No full textThe present work presents a numerical study of the neutral gas dynamics in the JET sub-divertor. A complex model of the sub-divertor geometry is implemented and successful comparisons between corresponding numerical and experimental data have been performed. The experimental data represent the neutral gas pressure obtained by a sub-divertor pressure gauge. The recently developed Divertor Gas Simulator (DIVGAS) which is based on the Direct Simulation Monte Carlo (DSMC) method is applied. DIVGAS is able to predict the behaviour of the flow including macroscopic quantities of practical interest as for instance the pressure, temperature and bulk velocity. The non-linear feedback of the sub-divertor gas flow on the divertor plasma vicinity is not taken into account. For all presented plasma cases, the deduced flow pattern is non -isothermal and covers the free molecular up to the transition flow regime. Furthermore, for low intermediate and high divertor density simulations, recirculation effects occur through gaps between the vertical target tiles, which seem to be two order of magnitude less compared with the recycling ion flux onto the divertor walls. (C) 2017 Elsevier B.V. All rights reserved
Governance structure, technical change, and industry competition
No full textGuerini M, Harting P, Napoletano M. Governance structure, technical change, and industry competition. Journal of Economic Dynamics and Control. 2022;135: 104294.We develop a model to study the impact of corporate governance on the investment de-cisions of firms and competition in an industry populated by publicly owned firms. A bar-gaining process between firm's stakeholders determines the optimal allocation of financial resources between real investments in R&D and financial investments in shares buybacks. We characterize the relation between governance and investment strategy and we study how different governance structures shape technical progress and competition over the industrial life cycle. Numerical simulations of a calibrated set-up of the model show that pooling together industries characterized by heterogeneous governance structures generate the well-documented inverted-U shaped relation between competition and innovation. (c) 2021 Elsevier B.V. All rights reserved
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