Observational diagnostics of gas in protoplanetary disks

Protoplanetary disks are composed primarily of gas (99% of the mass). Nevertheless, relatively few observational constraints exist for the gas in disks. In this review, I discuss several observational diagnostics in the UV, optical, near-IR, mid-IR, and (sub)-mm wavelengths that have been employed to study the gas in the disks of young stellar objects. I concentrate in diagnostics that probe the inner 20 AU of the disk, the region where planets are expected to form. I discuss the potential and limitations of each gas tracer and present prospects for future research.Comment: Review written for the proceedings of the conference "Origin and Evolution of Planets 2008", Ascona, Switzerland, June 29 - July 4, 2008. Date manuscript: October 2008. 17 Pages, 6 graphics, 134 reference

Conditioned Yield Response of Corn Hybrids to Tillage and the Insecticides Used in Breeding Programs

Researchers have reported differential and conflicting responses of com (Zea mays L.) to insecticides. Our research was conducted to determine if tillage and corn genotypes cause the variation in response. Two experiments were conducted. In one 3-yr study no-tillage (NT) and conventional tillage (CT) were main plots and four insecticide treatments were split plots (2.2 kg a.i. Carbofuran ha-I (CF 2.2), 1.1 kg a.i. Carbofuran ha- 1 (CF l. I), 2.2 kg a.i. Terbufos ha-1 (TF 2.2), and a untreated control (C). In the other study six hybrids were main plots with the same insecticides as split plots. Grain yield was measured at harvest. Treatments with CF 2.2 gave higher grain yield in NT, but TF 2.2 gave equal grain response in CT. When "Asgrow RX777" (developed using TF) was treated with TF 2.2, it averaged 32 q ha-I more grain than the C. Also, "Dekalb XL71" (developed using CF) yield 28 q ha-1 more grain with CF 2.2 than with the C. These results suggested that a hybrid will respond better to the insecticide used during its breeding development

The Influence of Varied Stem Maturity on Rooting of Caribbean Oregano (Lippia micromera S.)

Different stages of vegetative maturity influence rooting potential of sten-i cuttings. Oregano is in high demand in the international herb market. Four experiments were conducted in spring and fall of 1990 and I 991 to: 1) detennine optimum stem maturity stage for cutting propagation of Caribbean oregano (Lippia micromera S. ), and 2) determine seasonal differences in its rooting capabilities. Hardwood main stems, hardwood secondary sterns, softwood stem tips, and semi-hardwood stern tips were plac_ed upright in perlite using a hotbed. Bottom heat temperature was 28°C for all exp. At 21 days, shoot growth (SG), and root length (RL) ratings and rooting percent data showed highly significant difference between stem cuttings. Softwood stem tips gave plants with the best shoot growth and root system regardless of the season. Increased wood maturity negatively influenced rooting potential for fall propagated cuttings

A Multispecies Herbicide Screening Test for the Phytotoxicity Evaluation of Four Herbicides on Seven Spices

A herbicide screening experiment determined the phytotoxicity (phyto) effect of norflurazon (NOR), simazine (SIM), bentazon (BEN), dicamba (DIC) and a nontreated control on sage (Salvia O/ficinalis L.), pot marjoram (Origanum onites), wild marjoram (Origanum vulgare subsp. vulgare), lavender (Lamndula angustifolia), winter savory (Satureja Montana), rosemary (Rosmarinus officinalis L.), and sweet marjoram (Origanum mejorana). A stripsplit plot design with four reps was sprayed with each herbicide at three rates. Phyto rating was determined 21 days after application. Differences between herbicides, rates and spices was significant. Interactions between each paii of factors and between the three treatments were significant. NOR proved to be the least phytotoxic herbicide. NOR was safe at½ X in wild marjoram, lavender, winter savory, rosemary and sweet marjora!D and at 1 X in lavender and rosemary; BEN at 112 X in sage, pot marjoram, winter savory and rosemary, and at 1 X in rosemary; and DIC at½ X in sage, rosemary and sweet marjoram showed potential. SIM killed the exposed plants at all rates