Labor Specialization and Endogenous Growth

International Development, Labor and Human Capital,

Education, Job Signaling, and Dual Labor Markets in Developing Countries

An overlapping generational model of educational investment in a dual labor markets is presented in which education serves both as a screening device and as investment in human capital. Labor market dualism arises not only via the conventional technology (productivity) differential between a primary and a secondary sector, but also by a higher than a labor market clearing wage in the primary sector, to insure no shirking by the workers (an element shared with the efficiency wage theories). The important determinants of the workers' educational investment decision are the degree of discipline in the labor market and the cost of education. Among the three most commonly discussed educational policies of maximizing the number of the educated, maximizing the primary sector employment and maximizing social welfare, the last one, i.e., the most efficient one, leads to a lower level of education subsidy by the government.Labor and Human Capital,

Binding and PRO in the SPEC of NP

This article is an attempt to analyze some facts concerning around the binding theory under a new assumption based on the A/A′-division of the subjects of NP suggested in Kim(l987). In section 1, the motivation and explanatory power of the division is briefly reviewed, followed by a new interpretation and assumption of the structure of NP. In section 2, the problem of positing PRO in the SPEC of NP is discussed. The theories for the PRO in the SPEC of NP and those against the PRO in the SPEC of NP are carefully examined to draw the conclusion that PRO must be posited in the SPEC of NP. Especially in section 2.2., it is argued that the intermediate projection N' of an NP is actually acting as a maximal projection and should be understood as such at least for a proper analysis of binding phenomena in English NPs. The new assumption of the structure of NP not only enable us to analyze data without any extra conditon or cost to the standard binding theory, but also gives a unified explanation of previously problematic failure of complementary distribution between anaphors and pronominals.This paper was supported by Daewoo Foundation under 1987 Post-Graduate Grant

Labor specialization, agglomeration economies, and regional resource allocation

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCHBibliography: leaves 142-149.by Sunwoong Kim.Ph.D

Microstructure and Mechanical Properties of the Butt Joint in High Density Polyethylene Pipe

The microstructure and mechanical properties of the butt joint in high density polyethylene (HDPE) pipes were evaluated by preparing the joints with increasing the cooling time from 10 s to 70 s before pressure created for fusion of the pipes. Here, cold fusion flaws in HDPE butt joint were created with increasing the cooling time around 70 s caused by the close molecular contact followed by insufficient interdiffusion of chain segments back and forth across the wetted interface. The tensile failure mechanism of the welded pipes at different fusion time was projected based on the tensile test of dog-bone shaped, fully notched bar type as well as round U-notched specimens. The mechanical properties of the joints at different fusion time were correlated with the corresponding fracture surface morphology. The weld seam as well as tensile fracture surfaces were etched using strong oxidizing agents. The crystallinity of surface etched weld zone by potassium permanganate based etchant was found higher than unetched sample due to the higher susceptibility of amorphous phase of polyethylene with oxidizing agent. The U-notched tensile test of butt welded HDPE pipe and surface etching of the weldments provided clear delineation about the joint quality

Synthesis of Metal Oxide Decorated Polycarboxyphenyl Polymer-Grafted Multiwalled Carbon Nanotube Composites by a Chemical Grafting Approach for Supercapacitor Application

We present grafting of polycarboxyphenyl polymer on the surface of multiwalled carbon nanotube (MWCNT) via a free radical polymerization and subsequent anchoring of the metal oxide nanoparticles for the evaluation of their potential applicability to supercapacitor electrodes. Here, metal oxide nanoparticles, Fe3O4 and Sm2O3, were created after the oxidation of metal precursors Sm(NO3)3 and FeCl2, respectively, and attached on the surface of polycarboxyphenyl-grafted MWCNT (P-CNT) in aqueous medium. This approach shows a potential for enhancing the dispersion of Fe3O4 and Sm2O3 nanoparticles on the wall of P-CNT. The structure and morphological characteristics of the purified MWCNT, P-CNT, and metal oxide-anchored polycarboxyphenyl-grafted MWCNT (MP-CNT) nanocomposites were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The electrochemical performance of the purified MWCNT electrode, P-CNT electrode, and MP-CNT electrodes was tested by cyclic voltammetry (CV) and galvanostatic charge discharge in a 1.0 M H2SO4 aqueous electrolyte. The results showed that the specific capacitance of the purified MWCNT was 45.3 F/g at the scan rate of 5 mV/s and increased to 54.1 F/g after the modification with polycarboxyphenyl polymer. Further modification of P-CNT with Sm2O3 and Fe3O4 improved the specific capacitance of 65.84 F/g and 173.38 F/g, respectively, at the same scan rate

Gold Nanoparticle-Enhanced and Roll-to-Roll Nanoimprinted LSPR Platform for Detecting Interleukin-10

Localized surface plasmon resonance (LSPR) is a powerful platform for detecting biomolecules including proteins, nucleotides, and vesicles. Here, we report a colloidal gold (Au) nanoparticle-based assay that enhances the LSPR signal of nanoimprinted Au strips. The binding of the colloidal Au nanoparticle on the Au strip causes a red-shift of the LSPR extinction peak, enabling the detection of interleukin-10 (IL-10) cytokine. For LSPR sensor fabrication, we employed a roll-to-roll nanoimprinting process to create nanograting structures on polyethylene terephthalate (PET) film. By the angled deposition of Au on the PET film, we demonstrated a double-bent Au structure with a strong LSPR extinction peak at ~760 nm. Using the Au LSPR sensor, we developed an enzyme-linked immunosorbent assay (ELISA) protocol by forming a sandwich structure of IL-10 capture antibody/IL-10/IL-10 detection antibody. To enhance the LSPR signal, we introduced colloidal Au nanocube (AuNC) to be cross-linked with IL-10 detection antibody for immunogold assay. Using IL-10 as a model protein, we successfully achieved nanomolar sensitivity. We confirmed that the shift of the extinction peak was improved by 450% due to plasmon coupling between AuNC and Au strip. We expect that the AuNC-assisted LSPR sensor platform can be utilized as a diagnostic tool by providing convenient and fast detection of the LSPR signal. © Copyright © 2020 Baek, Song, Lee, Kim, Kim, Wi, Ok, Park, Hong, Kwak, Lee and Nam.1