Manual for starch gel electrophoresis: A method for the detection of genetic variation

The procedure to conduct horizontal starch gel electrophoresis on enzymes is described in detail. Areas covered are (I) collection and storage of specimens, (2) preparation of tissues, (3) preparation of a starch gel, (4) application of enzyme extracts to a gel, (5) setting up a gel for electrophoresis, (6) slicing a gel, and (7) staining a gel. Recipes are also included for 47 enzyme stains and 3 selected gel buffers. (PDF file contains 26 pages.

Observations of the rotational transitions of OH from the Orion molecular cloud

A summary of observed rotationally excited, far infrared OH line emissions from Orion-KL made using the Kuiper Airborne Observatory is given, together with a list of the resulting publications, talks, and lectures based on this data. In addition, a paper is appended, particularly addressing the (16)OH and (18)OH emission from Orion-KL. The first detections of the (16)OH (2)pi(1/2) to (2)pi(3/2) J = 3/2(-) to 3/2(+) rotational cross-ladder transition (53.351 micrometer) and the (18)OH (2)pi(3/2) J = 5/2(+) to 3/2(-) rotational ground-state transition (120.1719 micrometer). It is found that both of these lines exhibit a P-Cygni profile

Theoretical HeI Line Intensities in Gaseous Nebulae: NGC 1976, 6572 and IC 4997

Smits has recently calculated theoretical He I intensities for a large number of lines for conditions appropriate to gaseous nebulae. These are likely to remain the definitive calculations for some time to come. A comparison of these line ratios with observed values in three nebulae reveals some discrepancies. We show that these discrepancies are reduced when collisional effects from the metastable 23S level are included, and that it is not necessary to invoke an unknown depopulation mechanism for the He I23S level

The Effects of Charge Transfer on the Thermal Equilibrium of Photoionized Nebulae

Charge transfer can affect both the ionization and thermal balance of astrophysical plasmas. Using the most recent rate coefficients and energy defects, we calculate the heating/cooling rates for charge transfer reactions between hydrogen and elements up to Z=30. We incorporate these values into the photoionization code CLOUDY. Results from models approximating a wide range of astrophysical objects and conditions suggest that charge transfer can make a significant contribution to the heating near the H ionization front, particularly in objects with a hard ionizing continuum or enhanced abundances. Charge transfer heating can also be important in regimes in which the usual heating/cooling agents are suppressed, such as the emission-line clouds near quasars. We list those reactions that are most important for determining the thermal balance, in the hopes of facilitating improved atomic data

Grains in Ionized Nebulae. II. Heavy-Element Depletion

The presence of grains in gaseous nebulae can have significant effects on the thermal balance and radiative line transfer in these objects. The depletion of condensable elements onto grains provides evidence that dust exists in the ionized regions of nebulae. In this paper, we consider the elements Sc, Ti, V, and Cr, all of which are strongly depleted in the general interstellar medium. We construct simple three-level atoms for several ions of these elements, and incorporate them into our photoionization code CLOUDY. For both a model planetary nebula and a model H II region, we find that several lines of these elements should be easily detectable, provided that their gas-phase abundances are solar. This suggests that these elements are strongly depleted in ionized regions of these nebulae. We quantify these expectations by defining and comparing line ratios which are relatively insensitive to stellar and nebular parameters with recently measured intensities of [V IV], [Cr IV], and [Cr V] lines in NGC 7027. We encourage both further theoretical and observational work on these ions

Temperature Fluctuations in Photoionized Nebulae

Recombination lines in gaseous nebulae frequently yield parent-ion abundances that are several times larger than abundances derived from forbidden lines. One possible explanation for this discrepancy is the presence of temperature fluctuations. We examine temperature fluctuations in model nebulae by utilizing Peimbert\u27s t2 parameter. We have run large grids of models, varying the stellar temperature and the total hydrogen density. We consider two abundance sets: The first uses typical planetary nebulae abundances, while the second examines the effect of increasing the metals and grains by a factor of 3. We also consider both a constant density distribution and one which varies sinusoidally with radius. We examine the method of deriving t2 observationally, which uses measured [O III] and Balmer temperatures. We find that this derived t2 shows no correlation with the t2 based on the integral definition. We discuss the reasons for this discrepancy, which include nonvalidity of some of the basic assumptions and theoretical and observational difficulties with the Balmer temperature. We find that, in high-metallicity objects especially, noncollisional contributions to [O III] λ4363 can significantly affect the derived temperature. We argue that while temperature fluctuations may result in non-negligible abundance corrections in some objects, they are insufficient to resolve the abundance discrepancy