Autumn bloom of antarctic pack-ice algae

An autumn bloom of sea-ice algae was observed from February to June of 1992 within the upper 0.4 meter of multiyear ice in the Western Weddell Sea, Antarctica. The bloom was reliant on the freezing of porous areas within the ice that initiated a vertical exchange of nutrient-depleted brine with nutrient-rich seawater. This replenishment of nutrients to the algal community allowed the net production of 1760 milligrams of carbon and 200 milligrams of nitrogen per square meter of ice. The location of this autumn bloom is unlike that of spring blooms previously observed in both polar regions.     

An Analysis of Urban Size and Territorial Location Effects on Employment Probabilities: The Spanish Case

The probability of being employed varies depending on several factors. Many of these are related to personal characteristics such as educational level, age, gender, or number and age of children. Nevertheless, other factors may be relevant, in particular the geographical environment. The purpose of this paper is to analyse the relevance of urban size and the position of each territory (in terms of its distance from large metropolises) for the probability of being employed in the Spanish economy. Following the set of economic regions suggested by Polése, Shearmur and Rubiera (2007 ), we try to explain the spatial patterns of employment distribution. Our results show some relevant differences between these alternative economic areas. We find that municipalities with similar sizes and located at a similar distance from a metropolis but belonging to different Autonomous Communities or provinces share similar employability patterns.     

Simulating the cumulative effects of multiple forest management strategies on landscape measures of forest sustainability

While the cumulative effects of the actions of multiple owners have long been recognized as critically relevant to efforts to maintain sustainable forests at the landscape scale, few studies have addressed these effects. We used the HARVEST timber harvest simulator to predict the cumulative effects of four owner groups (two paper companies, a state forest and non-industrial private owners) with different management objectives on landscape pattern in an upper Michigan landscape managed primarily for timber production. We quantified trends in landscape pattern metrics that were linked to Montreal Process indicators of forest sustainability, and used a simple wildlife habitat model to project habitat trends. Our results showed that most trends were considered favorable for forest sustainability, but that some were not. The proportion of all age classes and some forest types moved closer to presettlement conditions. The trend for the size of uneven-aged patches was essentially flat while the average size of patches of the oldest and youngest age classes increased and the size of patches of the remaining age classes decreased. Forest fragmentation generally declined, but edge density of age classes increased. Late seral forest habitat increased while early successional habitat declined. The owners use different management systems that cumulatively produce a diversity of habitats. Our approach provides a tool to evaluate such cumulative effects on other landscapes owned by multiple owners. The approach holds promise for helping landowner groups develop and evaluate cooperative strategies to improve landscape patterns for forest sustainability.     

X-ray Absorption Spectroscopic Investigation of Trace Vanadium Sites in Coal

X-ray absorption spectroscopy was used to probe the chemical and structural environment of vanadium in coal. It was found that vanadium exists in at least two environments, in both of which it was coordinated to oxygens. There was no evidence of vanadium in nitrogen (porphyrin) or sulfide environments. It was also found that the vanadium environments in the raw coal did not survive unchanged in a liquefaction process. These findings have implications for coal cleaning processes and for trace element release into the liquefaction process stream.     

Striatal nondopaminergic neurons: possible involvement in feeding and drinking behavior

Intracaudate injections of kainic acid destroy striatal neurons containing acetylcholine and gamma-aminobutyric acid but leave dopaminergic nerve terminals in this brain region intact. Rats injected with the drug are aphagic and adipsic, and have other behavioral abnormalities strikingly similar to those seen in animals with lesions in the dopaminergic nigrostriatal bundle.     

Ontogeny of adrenergic arousal and cholinergic inhibitory mechanisms in the rat

With spontaneous activity as a measure of arousal, dose response curves were established for scopolamine and amphetamine administered to 10-, 15-, 20-, 25-, and 100-day-old rats. Amphetamine always increased activity, but scopolamine had no efect on younger rats, which suggests that adrenergic excitatory areas in the brainstem mature more rapidly than cholinergic inhibitory areas in the forebrain.     

Iron deficiency stress response of various c‐3 and c‐4 grain crop genotypes: Strategy II mechanism evaluated

The relative amount of phytosiderophore produced by various Strategy II plants has been categorized as follows: barley (Hordeum vulgare L.) > wheat (Triticum aestivum L.) > oat (Avena byzantina C. Koch.) > rye (Secale cereale L.) >> corn (Zea mays L.) >> sorghum (Sorghum bicolor (L.) Moench) > rice (Oryza sativa L.). With the exception of rice, these plants developed under oxidized soil conditions, and the C‐3 species produce more phytosiderophore than C‐4 species under Fe‐deficiency stress. Iron‐efficient Coker 227 oat produced phytosiderophore in response to Fe‐deficiency stress, while Fe‐inefficient TAM 0–312 oat did not. Although Fe‐efficient WF9 corn and Fe‐inefficient ys₁ corn differed in their ability to obtain Fe, neither produced sufficient quantities of phytosiderophore to explain these differences. The objectives of this research were to determine: (a) if phytosiderophore production of Fe‐deficiency stressed C‐4 species millet (Panicum miliaceum L.) and corn is low or absent compared to identically stressed C‐3 species oat and barley, and (b) if native, inbred and hybrid corn cultivars differ in ability to produce and utilize phytosiderophores.

Although release of phytosiderophore for Fe‐stressed corn and millet was generally lower than oat, quantity of release was not always related to obtaining Fe and maintaining green plants. Barley maintained high leaf Fe and low chlorosis with a minor release of phytosiderophore. Oat with increased release acted similarly to barley, whereas a relatively high release of phytosiderophore from White maize did not effect Fe uptake or greening. Likewise, small amounts of phytosiderophore were produced by all corn types, but corn was generally unable to obtain adequate Fe from the growth medium. Two of the native corns, Coneso and Tepecintle, maintained relatively low chlorosis, but they differed in phytosiderophore release. Thus, it appears that the C‐4 plants studied herein generally release a lower amount of phytosiderophore than do C‐3 species, but overcoming Fe‐deficiency chlorosis is not guaranteed by such release. The Strategy II mechanism of mere release of phytosiderophore and consequential Fe acquisition appears simplistic. There is a need for understanding what other factors are involved.