131,858 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
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
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
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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