The Response of Aspen \u3ci\u3e(Populus Tremuloides)\u3c/i\u3e to Artificial Defoliation

(excerpt) In the summers of 1939 and 1940 hand defoliation oftrembling aspen, Populus tremuloides Michx., was carried on in a young stand located a few miles north of Itasca State Park. This study was undertaken to determine the response of aspen trees to several amounts of defoliation at four different times during the summer. Other similar artificial defoliation studies have been reported by Wallace (1945), Giese et al. (1964), Skilling (1964), Kulman (197 I), and Heichel and Turner (1976)

Social Dominance Orientation Connects Prejudicial Human-Human and Human-Animal Relations

Recent theorizing suggests that biases toward human outgroups may be related to biases toward (non-human) animals, and that individual differences in desire for group dominance and inequality may underlie associations between these biases. The present investigation directly tests these assumptions. As expected, the results of the current study (N = 191) demonstrate that endorsing speciesist attitudes is significantly and positively associated with negative attitudes toward ethnic outgroups. Importantly, individual differences in social dominance orientation accounted for the association between speciesist and ethnic outgroup attitudes; that is, these variables are associated due to their common association with social dominance orientation that underpins these biases. We conclude that social dominance orientation represents a critical individual difference variable underlying ideological belief systems and attitudes pertaining to both human-human intergroup and human-animal relations

Role of Insects and Diseases in a Jack Pine Provenance Study

Two jack pine plantations were established at the Cloquet Forestry Center, Cloquet, Minnesota, in 1942 and 1943, using trees originating from 22 sites in the United States and 10 in Canada. From 1945 to 1953 the incidence of attack by insects and diseases was recorded individually for all trees, and in 1980-1981 the diameter and form of both living and dead trees were recorded. There were differences in the incidence of attack by the pests and in tree response to early injury among the various seed sources. In 1980 and in 1981 there were differences in tree form resulting from insect and both living and dead pest-free trees had the best form. The diameter increases from 1955 to 1980-1981 were almost identical for all categories with the exception of the dead pest-free trees which had the smallest diameters

Soil pH governs production rate of calcium carbonate secreted by the earthworm Lumbricus terrestris

Lumbricus terrestris earthworms exposed to 11 soils of contrasting properties produced, on average, 0.8 ± 0.1 mgCaCO3 earthworm−1 day−1 in the form of granules up to 2 mm in diameter. Production rate increased with soil pH (r2 = 0.68, p < 0.01). Earthworms could be a significant source of calcite in soils

Copper Toxicity in Erwinia amylovora : An X-Ray Microanalytical Study

The effect of Cu2+ ions on the growth and elemental composition of the phytopathogenic bacterium Erwinia amylovora was investigated by in vitro culture in nutrient broth supplemented with CuSO4. No detectable inhibition in bacterial growth occurred with medium supplemented at 10-4M Cu (compared to control medium with no added Cu), but partial inhibition occurred at 10-3M Cu (limiting toxicity) and complete inhibition at 10-2M Cu. Under conditions of limiting toxicity, incubation in Cu2+ ions leads to a reduction in the general synthesis of cell materials and the formation of abnormally large cells with a small dry mass. X-ray analysis revealed the uptake of small levels of Cu2+ under these conditions, plus wide-ranging changes in other major elements present in the bacterial cells. These changes included a reduction in the level of K and increased levels of the divalent cations Ca and Fe. The results obtained are consistent with the toxic effect of Cu being mediated via its effect on the cell membrane, with internal elemental changes resulting from a perturbation of membrane permeability

Parenteral versus oral iron therapy for adults and children with chronic kidney disease

What is this review about? The use of intravenous compared with oral iron supplements in patients with chronic kidney disease (CKD)

Progress report on a new search for free e/3 quarks in the cores of 10(15) - 10(16) eV air showers

The Leeds 3 sq m Wilson cloud chamber is being used in a new search for free e/3 quarks close to the axes of 10 to the 15th power - 10 to the 16th power eV air showers. A ratio trigger circuit is used to detect the incidence of air shower cores; the position of the shower center and the axis direction are determined from photographs of current-limited spark chambers. It is thus possible, for the first time, to know where we have looked for quarks in air showers and to select for scanning only those cloud chamber photographs where we have good evidence that the shower axis was close to the chamber. 250 g/sq cm of lead/concrete absorber above the cloud chamber serve to reduce particle densities and make a quark search possible very close to the shower axes. The current status of the search is given

Everybody Knows: Engaged Research and the Changing Role of the Academic

The rise of the impact and engagement agendas has challenged the role of the academic, and particularly the relationship between the academic, knowledge and the wider public. In this article, we propose that, alongside the existing models of ‘knowledge transfer’ and ‘knowledge exchange’, academic engagement with external audiences can also be conceptualised as a multidimensional ‘knowledge network’. We adopt a case study approach to explore and illustrate what such a knowledge network looks like in practice, and we consider the implications of thinking about university engagement activities in these terms, with particular emphasis on what it means for the shifting role of the academic

Rfx6 Maintains the Functional Identity of Adult Pancreatic β Cells.

SummaryIncreasing evidence suggests that loss of β cell characteristics may cause insulin secretory deficiency in diabetes, but the underlying mechanisms remain unclear. Here, we show that Rfx6, whose mutation leads to neonatal diabetes in humans, is essential to maintain key features of functionally mature β cells in mice. Rfx6 loss in adult β cells leads to glucose intolerance, impaired β cell glucose sensing, and defective insulin secretion. This is associated with reduced expression of core components of the insulin secretion pathway, including glucokinase, the Abcc8/SUR1 subunit of KATP channels and voltage-gated Ca2+ channels, which are direct targets of Rfx6. Moreover, Rfx6 contributes to the silencing of the vast majority of “disallowed” genes, a group usually specifically repressed in adult β cells, and thus to the maintenance of β cell maturity. These findings raise the possibility that changes in Rfx6 expression or activity may contribute to β cell failure in humans