Magnetic-field measurements of T Tauri stars in the Orion Nebula cluster

We present an analysis of high-resolution ($R \sim 50,000$) infrared K-band echelle spectra of 14 T Tauri stars in the Orion Nebula Cluster. We model Zeeman broadening in three magnetically sensitive \ion{Ti}{1} lines near $2.2\ \mu$m and consistently detect kilogauss-level magnetic fields in the stellar photospheres. The data are consistent in each case with the entire stellar surface being covered with magnetic fields, suggesting that magnetic pressure likely dominates over gas pressure in the photospheres of these stars. These very strong magnetic fields might themselves be responsible for the underproduction of X-ray emission of T Tauri stars relative to what is expected based on main-sequence star calibrations. We combine these results with previous measurements of 14 stars in Taurus and 5 stars in the TW Hydrae association to study the potential variation of magnetic-field properties during the first 10 million years of stellar evolution, finding a steady decline in total magnetic flux with age.Comment: 34 pages, 17 figures, published in ApJ, 2011, 729, 8

Untersuchungen zur Biologie und den natürlichen Feinden von Deanolis sublimbalis SNELLEN (Lepidoptera, Pyralidae) an Mango in Papua New Guinea

Deanolis sublimbalis SNELLEN (Lepidoptera: Pyralidae), the red banded mango caterpillar (RMBC), is a Southeast Asian insect species. It is now widely distributed throughout this region (India, Burma, Thailand, China, Brunei, Philippines, Indonesia, and Papua New Guinea) and was recently detected for the first time on mainland Australia, but so far has not been recorded in Pakistan, Nepal, and Malaysia (WATERHOUSE 1998). In Papua New Guinea (PNG) it is nowadays widely distributed throughout the mainland and islands (WATERHOUSE 1998). Although infestation levels of 40 – 50 % were recorded in the Philippines (TIPON 1979), very little is known about the biology of this pest, and there are only few references in the literature, the results differing significantly (WATERHOUSE 1998). Due to the contradictory opinions on the biology published, the following study was undertaken to obtain the basic information required for the development of an appropriate management technique for this pest. In particular, the fundamental data to clarify in the course of this study were: 1. life history and behaviour of RMBC, especially when mango is out of season. 2. search for other host plants of RMBC. 3. search for natural enemies of RMBC.Dt. Titel: Untersuchungen zur Biologie und den natürlichen Feinden von Deanolis sublimbalis SNELLEN (Lepidoptera, Pyralidae) an Mango in Papua New Guinea An vier Standorten in der Central Province von Papua Neuguinea wurde D. sublimbalis untersucht. Eier wurden fast immer am Fruchtstiel unter vertrockneten Blütenblättern abgelegt, meist zu 2-4. Eiablage auf die Früchte war sehr selten. Larven wurden in den Früchten von Mangifera indica, M. minor und M. odorata gefunden, nie an den anderen Anacardiaceen Spondias spp. und Anacardium occidentale oder den Myrtaceen Syzygium spp. Im Labor entwickelten sich in Früchten von A. occidentale (Cashew-Baum) nur 5 % der Larven zur Imago. Präpuppen und Puppen wurden nur unter der Rinde der Mangobäume gefunden oder in tiefen Rissen der Rinde. Parasitoide oder Pathogene der Eier oder Larven wurden nicht festgestellt. Die Prädatoren, wie die Weberameise Oecophylla smaragdina (F.), spielten bei D. sublimbalis keine Rolle

Surface Plasmon Microscopy of Two Crystalline Domains in a Lipid Monolayer

Surface plasmon microscopy is applied to monolayers of dimyristoylphosphatidylethanolamine,dipcast at high lateral pressure (35 mN/m) on a solid substrate. The vertical resolution of better than 1 nm and an in-plane resolution of - 10 um allow for the detection of two separate solid domains. Assuming a fixed value for the lipid refractive index, the tilt angles of the lipid aliphatic chains were determined to be 0° and -35°, respectively

Research investigation of electrical discharge fragmentation for protein structure identification Final report

Electrical discharge fragmentation device for determination of bacteria fragmentation pattern

Possible detection of a magnetic field in T Tauri

Medium-resolution $(R\simeq 15000)$ circular spectropolarimetry of T Tauri is presented. The star was observed twice: on November 11, 1996 and January 22, 2002. Weak circular polarization has been found in photospheric absorption lines, indicating a mean surface longitudinal magnetic field $B_{\|}$ of $160\pm 40$ G and $140\pm 50$ G at the epoch of the first and second observations respectively. While these values are near the detection limit of our apparatus, we belive that they are real. In any case one can conclude from our data that $B_{\|}$ of T Tau does not significantly exceed 200 G, which is much less than surface magnetic field strength of the star ($>2.3$ kG) found by Guenther et al. (1999) and Johns-Krull et al. (2000). We discuss possible reasons of this difference.Comment: 5 pages, 3 figure