Do Foreign Investors Destabilize Stock Markets? The Korean Experience in 1997

This paper examines the impact of foreign investors on stock returns in Korea from November 30, 1996, to the end of 1997 using trade data. We find strong evidence of positive feedback trading and herding by foreign investors before the period of Korea's economic crisis during the last three months of 1997. The evidence of herding becomes weaker during the crisis period and positive feedback trading by foreign investors disappears. We find no evidence that trades by foreign investors had a destabilizing effect on Korea's stock market over our sample period. In particular, the market adjusted quickly and efficiently to large sales by foreign investors and these sales were not followed by negative abnormal returns amplifying their impact.

Hyperon-nucleon coupling from QCD sum rules

The NKY coupling constant for $Y = \Lambda$ and $\Sigma$ is evaluated in a QCD sum rule calculation. We discuss and extend the result of a previous analysis in the $\rlap{/}{q}i\gamma_5$ structure and compare it with the result obtained with the use of the $\gamma_5 \sigma_{\mu \nu}$ structure. We find a huge violation of the SU(3) symmetry in the $\gamma_5 \sigma_{\mu \nu}$ structure.Comment: 4 pages, 2 figures, espcrc2.sty included. Talk presented at QCD99, Montpellier, France (to appear in Nucl.Phys.B Proc.Suppl.

Do Domestic Investors Have an Edge? The Trading Experience of Foreign Investors in Korea

We investigate whether domestic investors have an edge over foreign investors in trading domestic stocks.Using Korean data, we show that foreign money managers pay more than domestic money managers when they buy and receive less when they sell for medium and large trades. The sample average daily trade-weighted disadvantage of foreign money managers is of 21 basis points for purchases and 16 basis points for sales. There is also some evidence that domestic individual investors have an edge over foreign investors. The explanation for these results is that prices move more against foreign investors than against domestic investors before trades.

Do Domestic Investors Have More Valuable Information About Individual Stocks Than Foreign Investors?

Using trade data from Korea from December 1996 to November 1998, we find evidence that domestic individual investors have a short-lived private information advantage for individual stocks over foreign investors, but almost no evidence that domestic institutional investors have such an advantage. Foreign investors trade at worse prices than resident investors for large trades, for smaller stocks, and more so for sales than for purchases. Foreign investors sell to domestic investors before a stock has a large positive abnormal return and buy from domestic investors before a stock has a large negative abnormal return. Using intraday data, the large trades of domestic individual investors have more information than the large trades of foreign investors or of domestic institutional investors.

Suboptimal Larval Habitats Modulate Oviposition of the Malaria Vector Mosquito Anopheles coluzzii.

Selection of oviposition sites by gravid females is a critical behavioral step in the reproductive cycle of Anopheles coluzzii, which is one of the principal Afrotropical malaria vector mosquitoes. Several studies suggest this decision is mediated by semiochemicals associated with potential oviposition sites. To better understand the chemosensory basis of this behavior and identify compounds that can modulate oviposition, we examined the generally held hypothesis that suboptimal larval habitats give rise to semiochemicals that negatively influence the oviposition preference of gravid females. Dual-choice bioassays indicated that oviposition sites conditioned in this manner do indeed foster significant and concentration dependent aversive effects on the oviposition site selection of gravid females. Headspace analyses derived from aversive habitats consistently noted the presence of dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS) and 6-methyl-5-hepten-2-one (sulcatone) each of which unitarily affected An. coluzzii oviposition preference. Electrophysiological assays across the antennae, maxillary palp, and labellum of gravid An. coluzzii revealed differential responses to these semiochemicals. Taken together, these findings validate the hypothesis in question and suggest that suboptimal environments for An. coluzzii larval development results in the release of DMDS, DMTS and sulcatone that impact the response valence of gravid females

Full-coverage film cooling heat transfer study: Summary of data for normal-hole injection and 30 deg slant-hole injection

Heat transfer to a full coverage film cooled turbulent boundary layer over a flat surface was studied. The surface consisted of a discrete hole test section containing 11 rows of holes spaced 5 diameters apart in a staggered array and an instrumented recovery region. Ten diameter spacing was also studied by plugging appropriate holes. Two test sections were used, one having holes normal to the surface and the other having holes angled 30 deg to the surface in the downstream direction. Stanton number data were obtained both in the full coverage region and in the downstream recovery region for a range of blowing ratios, or mass flux ratios, from 0 to 1.3. Initial conditions at the upstream edge of the blowing region were varied from 500 to 5000 for momentum thickness Reynolds number and from 100 to 1800 for enthalpy thickness Reynolds number. The range of Reynolds numbers based on hole diameter and mainstream velocity was 6000 to 22000. Initial boundary layer thicknesses range from 0.5 to 2.0 hole diameters. Air was used as the working fluid. The data were taken for the secondary injection temperature equal to the wall temperature and also equal to the mainstream temperature. Superposition was then used to obtain Stanton number as a continuous function of the injectant temperature. The heat transfer coefficient was defined on the basis of a mainstream-to-wall temperature difference. This definition permits direct comparison of performance between film cooling and transpiration cooling

Inflationary Hubble Parameter from the Gravitational Wave Spectrum in the General Slow-roll Approximation

Improved general slow-roll formulae giving the primordial gravitational wave spectrum are derived in the present work. Also the first and second order general slow-roll inverse formulae giving the Hubble parameter $H$ in terms of the gravitational wave spectrum are derived. Moreover, the general slow-roll consistency condition relating the scalar and tensor spectra is obtained

Inhibitory control as a mediator of bidirectional effects between early oppositional behavior and maternal depression.

Maternal depression is an established risk factor for child conduct problems, but relatively few studies have tested whether children's behavioral problems exacerbate mothers' depression or whether other child behavioral characteristics (e.g., self-regulation) may mediate bidirectional effects between maternal depression and child disruptive behavior. This longitudinal study examined the parallel growth of maternal depressive symptoms and child oppositional behavior from ages 2 to 5; the magnitude and timing of their bidirectional effects; and whether child inhibitory control, a temperament-based self-regulatory mechanism, mediated effects between maternal depression and child oppositionality. A randomized control trial of 731 at-risk families assessed children annually from ages 2 to 5. Transactional models demonstrated positive and bidirectional associations between mothers' depressive symptoms and children's oppositional behavior from ages 2 to 3, with a less consistent pattern of reciprocal relations up to age 5. Mediation of indirect mother-child effects and child evocative effects depended on the rater of children's inhibitory control. Findings are discussed in regard to how child evocative effects and self-regulatory mechanisms may clarify the transmission of psychopathology within families