Essays on sorting and globalization

"Leaping into the future of labor economics: the research potential of linking employer and employee data" is the title of a paper by Daniel S Hammermesh published in Labour Economics in 1999. I quote it here, since it captures much of my motivation for the work included in this thesis. Considering applied micro econometrics and labor economics my main elds of interest, the development of linked employer-employee data that took place in Denmark around the time of the new millennium, marked new and exciting possibilities. For some years Danish researchers have had access to very detailed information on all people living in Denmark, but at the beginning of this century also data on all companies linked to these persons was being made available for research. Combined with modern computer technology this meant access to a linked database following all employers and all employees in Denmark over time. I had no doubt that this should be the centerpiece of my Ph.D. The result has been two lines of research, one studying the e¤ect of globalization on labor demand in Denmark, and one studying sorting, that is, how and why employers meet employees in the labor market. In the summary I treat each line of research independently although I would like to emphasize, that studying a labor market where fi rms and workers reacts to one another is the corner stone in both

Autobiographical and semantic memory of adolescent drug users

BACKGROUND: Psychiatric disorders in infancy and adolescence may impair the access to the memory of facts and events occurred during these periods. OBJECTIVE: The main purpose of this study was to investigate the autobiographical and semantic memory of a group of adolescent drug users and a control group of adolescent non-users. METHODS: Twenty-five males participated in each group between 13 and 17 years old. Two questionnaires were applied: Kihlstrom e Schacter (1995) for semantic memory and Borrini et al. (1989) for autobiographical memory. RESULTS: The group of drug users had more difficulties in accessing autobiographical memory (p = 0.0205) and semantic memory (p = 0.0057). CONCLUSIONS: Some hypotheses might be raised: users presented cognitive complications that make difficult the access to long-term memories, as well as others related to the dynamics of drug use.CONTEXTO: Transtornos psiquiátricos na infância e adolescência podem prejudicar o acesso às memórias de fatos e eventos ocorridos durante esse período. OBJETIVO: O objetivo deste estudo foi investigar as memórias autobiográfica e semântica de adolescentes usuários e não usuários de drogas. MÉTODOS: Participaram de cada grupo 25 adolescentes do gênero masculino, com idades entre 13 e 17 anos. Dois questionários foram aplicados: Kihlstrom e Schacter (1995), que avalia a memória semântica e Borrini et al. (1989), que avalia a memória autobiográfica. RESULTADOS: O grupo de usuários de drogas apresentou maior dificuldade para acessar as memórias autobiográfica (p = 0,0205) e semântica (p = 0,0057). CONCLUSÕES: Algumas hipóteses podem ser levantadas: usuários apresentam complicações cognitivas que dificultam o acesso às memórias de longo prazo, e também outras causas relacionadas à dinâmica do uso de drogas

Combinatorial functions of two chimeric antibodies directed to human CD4 and one directed to the a-chain of the human interleukin-2 receptor

The general feasibility of chimerization of monoclonal antibodies (mAbs) has already been shown for a large number of them. In order to evaluate in vitro parameters relevant to immunosuppressive therapy, we have chimerized and synthesized two anti-CD4 mAbs recognizing two different epitopes on the human T-lymphocyte antigen, CD4. The chimerized mAbs are produced at levels corresponding to those of the original hybridoma cell lines. With respect to activation of human complement, the individual Abs are negative; however, when used in combination, complement activation was performed. When applied in combination, they were found to modulate the CD4 antigen, whereas the individual mAb do not display this property. Individually they mediate an up to 60% inhibition of the mixed lymphocyte reaction (MLR). However, by combination of an anti-CD4 mAb with one directed against the a-chain of the human IL2 receptor, nearly 100% inhibition of the MLR was achieved, even with reduced dosage of the mAbs. Our data suggest that the combination of an anti-CD4 mAb and an anti-IL2Rcc chain mAb is more effective with respect to immunosuppression than each mAb by itself, indicating that this mAb cocktail could be a new strategy for immunosuppressive therapy

The Implications of Globalization for Firms` Demand for Skilled and Unskilled Labor.

This paper investigates the impact of globalization, in the sense of increasing international trade, on the demand for skills in Danish manufacturing companies. The study is based on a unique data set that enables us to develop rich measures of international outsourcing and import penetration. Moreover, the data also allows several strategies to strengthen the causal interpretation of our results. The main finding of the analysis is that it is of crucial importance to distinguish imports - both in the form of outsourcing and overall imports - by country-of-origin. We find that international trade with low-wage countries leads to skill-upgrading. This is especially pronounced for import penetration with a ceteris paribus contribution of around fifty percent to skill-upgrading. Moreover, we find that import penetration in goods originating from high-wage countries lead to skill-downgrading. This latter result suggests that Danish manufacturing has comparative advantage in skill intensive production when compared to low-wage countries, but in unskill-intensive production when compared to high-wage countries. Skill-upgrading, Low-wage country outsourcing, Low-wage country import penetration, Comparative advantag

Bistable Helmholtz bright solitons in saturable materials

We present, to the best of our knowledge, the first exact analytical solitons of a nonlinear Helmholtz equation with a saturable refractive-index model. These new two-dimensional spatial solitons have a bistable characteristic in some parameter regimes, and they capture oblique (arbitrary-angle) beam propagation in both the forward and backward directions. New conservation laws are reported, and the classic paraxial solution is recovered in an appropriate multiple limit. Analysis and simulations examine the stability of both solution branches, and stationary Helmholtz solitons are found to emerge from a range of perturbed input beams

Dark solitons at nonlinear interfaces

The refraction of dark solitons at a planar boundary separating two defocusing Kerr media is simulated and analyzed, for the first time (to our knowledge). Analysis is based on the nonlinear Helmholtz equation and is thus valid for any angle of incidence. A new law, governing refraction of black solitons, is combined with one describing bright soliton refraction to yield a generalized Snell’s law whose validity is verified numerically. The complexity of gray soliton refraction is also analyzed, and illustrated by a change from external to internal refraction on varying the soliton contrast parameter

Governance models for nature-based solutions: Seventeen cases from Germany

Nature-based solutions (NBS) for mitigating climate change are gaining popularity. The number of NBS is increasing, but research gaps still exist at the governance level. The objectives of this paper are (i) to give an overview of the implemented NBS for flood risk management and mitigation in Germany, (ii) to identify governance models that are applied, and (iii) to explore the differences between these models. The results of a hierarchical clustering procedure and a qualitative analysis show that while no one-size-fits-all governance model exists, polycentricism is an important commonality between the projects. The study concludes by highlighting the need for further research on traditional governance model reconversion and paradigm changes. We expect the findings to identify what has worked in the past, as well as what is important for the implementation of NBS for flood risk management in future projects.Horizon 2020 Framework Programme http://dx.doi.org/10.13039/100010661Bundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347Horizon 2020 http://dx.doi.org/10.13039/501100007601Horizon 2020 ()Technische Universität München (1025)Peer Reviewe

Liver-directed chemotherapy of cetuximab and bevacizumab in combination with oxaliplatin is more effective to inhibit tumor growth of CC531 colorectal rat liver metastases than systemic chemotherapy

Colorectal carcinoma is, through to its high rate of liver metastasis (mCRC), the second most cause of cancer death worldwide. Tumor resection represents the only potential cure. In cases of unresectable disease systemic chemotherapy (sCHT) remains the therapy of choice. Modern sCHT regimens including biological agents can induce tumor response that leads to curative surgery of initially unresectable mCRC. However, liver-directed therapy via hepatic arterial infusion (HAI) may produce higher response rates than sCHT. Herein we studied whether a HAI of cetuximab (CE) plus bevacizumab (BE) with or without oxaliplatin (OX) can inhibit tumor growth in a rat model. WAG/Rij rats underwent subcapsular hepatic tumor implantation. After 10 days animals received either HAI or sCHT of CE plus BE, OX or all three drugs. Saline-treated animals served as controls. Tumor growth was estimated at day 10 and 13. On day 13 liver and tumor tissue was studied histologically and immunohistochemically. In controls the tumors grew about 50 %. OX alone was not capable of inhibiting tumor growth. In contrast, CE plus BE given as HAI significantly reduced tumor growth compared to sCHT (p < 0.05). HAI of CE plus BE combined with OX yielded an even more pronounced inhibition of tumor growth. Immunohistochemistry revealed a decreased tumor cell proliferation and tumor vascularization. The present study demonstrates that HAI of CE plus BE is effective to inhibit tumor growth. This effect is even more pronounced in combination with OX. Systemic application of these agents cannot achieve comparable effects

The Lifetime of FRIIs in Groups and Clusters: Implications for Radio-Mode Feedback

We determine the maximum lifetime t_max of 52 FRII radio sources found in 26 central group galaxies from cross correlation of the Berlind SDSS group catalog with the VLA FIRST survey. Mock catalogs of FRII sources were produced to match the selection criteria of FIRST and the redshift distribution of our parent sample, while an analytical model was used to calculate source sizes and luminosities. The maximum lifetime of FRII sources was then determined via a comparison of the observed and model projected length distributions. We estimate the average FRII lifetime is 1.5x10^7 years and the duty cycle is ~8x10^8 years. Degeneracies between t_max and the model parameters: jet power distribution, axial ratio, energy injection index, and ambient density introduce at most a factor of two uncertainty in our lifetime estimate. In addition, we calculate the radio active galactic nuclei (AGN) fraction in central group galaxies as a function of several group and host galaxy properties. The lifetime of radio sources recorded here is consistent with the quasar lifetime, even though these FRIIs have substantially sub-Eddington accretion. These results suggest a fiducial time frame for energy injection from AGN in feedback models. If the morphology of a given extended radio source is set by large-scale environment, while the lifetime is determined by the details of the accretion physics, this FRII lifetime is relevant for all extended radio sources.Comment: 18 pages, 7 figures. Accepted for publication in ApJ. High resolution paper available at http://www.astronomy.ohio-state.edu/~bird/BMK07.pd

Radio lobes and X-ray hot spots in the microquasar S26

We have studied the structure and energetics of the powerful microquasar/shock-ionized nebula S26 in NGC 7793, with particular focus on its radio and X-ray properties. Using the Australia Telescope Compact Array, we have resolved for the first time the radio lobe structure and mapped the spectral index of the radio cocoon. The steep spectral index of the radio lobes is consistent with optically-thin synchrotron emission; outside the lobes, the spectral index is flatter, suggesting an additional contribution from free-free emission, and perhaps ongoing ejections near the core. The radio core is not detected, while the X-ray core has a 0.3-8 keV luminosity ~6 x 10^{36} erg/s. The size of the radio cocoon matches that seen in the optical emission lines and diffuse soft X-ray emission. The total 5.5-GHz flux of cocoon and lobes is ~2.1 mJy, which at the assumed distance of 3.9 Mpc corresponds to about 3 times the luminosity of Cas A. The total 9.0-GHz flux is ~1.6 mJy. The X-ray hot spots (combined 0.3-8 keV luminosity ~2 x 10^{37} erg/s) are located ~20 pc outwards of the radio hot spots (ie, downstream along the jet direction), consistent with a different physical origin of X-ray and radio emission (thermal-plasma and synchrotron, respectively). The total particle energy in the bubble is ~10^{53} erg: from the observed radio flux, we estimate that only about a few 10^{50} erg are stored in the relativistic electrons; the rest is in protons, nuclei and non-relativistic electrons. The X-ray-emitting component of the gas in the hot spots contains ~10^{51} erg, and ~10^{52} erg over the whole cocoon. We suggest that S26 provides a clue to understand how the ambient medium is heated by the mechanical power of a black hole near its Eddington accretion rate.Comment: Accepted by MNRAS on 2010 July 12. Twelve pages, 8 figures, size = 1.3 MB. Contact the authors for higher-res figure