Interacting Factors Driving a Major Loss of Large Trees with Cavities in a Forest Ecosystem

Large trees with cavities provide critical ecological functions in forests worldwide, including vital nesting and denning resources for many species. However, many ecosystems are experiencing increasingly rapid loss of large trees or a failure to recruit new large trees or both. We quantify this problem in a globally iconic ecosystem in southeastern Australia – forests dominated by the world''s tallest angiosperms, Mountain Ash (Eucalyptus regnans). Tree, stand and landscape-level factors influencing the death and collapse of large living cavity trees and the decay and collapse of dead trees with cavities are documented using a suite of long-term datasets gathered between 1983 and 2011. The historical rate of tree mortality on unburned sites between 1997 and 2011 was >14% with a mortality spike in the driest period (2006–2009). Following a major wildfire in 2009, 79% of large living trees with cavities died and 57–100% of large dead trees were destroyed on burned sites. Repeated measurements between 1997 and 2011 revealed no recruitment of any new large trees with cavities on any of our unburned or burned sites. Transition probability matrices of large trees with cavities through increasingly decayed condition states projects a severe shortage of large trees with cavities by 2039 that will continue until at least 2067. This large cavity tree crisis in Mountain Ash forests is a product of: (1) the prolonged time required (>120 years) for initiation of cavities; and (2) repeated past wildfires and widespread logging operations. These latter factors have resulted in all landscapes being dominated by stands ≤72 years and just 1.16% of forest being unburned and unlogged. We discuss how the features that make Mountain Ash forests vulnerable to a decline in large tree abundance are shared with many forest types worldwide.     

EXPERIENCE WITH ACTH AND CORTISONE IN PRIVATE PRACTICE

ACTH and cortisone are highly nonspecific in their action. A fundamental portion of the mechanism of action is the interposition of a blockade between toxin and end organ. This effect can be of great benefit in the management of a variety of acute and chronic diseases.A major hazard constantly to be kept in mind is the potential masking of advancing disease. This consideration makes concomitant chemotherapy mandatory in the presence of specific infections.In chronic diseased states it should be assumed that prolonged therapy will be necessary. Treatment should not be instituted unless such continued therapy is physiologically and economically feasible.     

Visualisation of metal deposition in biofilm reactors by three-dimensional magnetic resonance imaging (MRI)

Three-dimensional magnetic resonance imaging (MRI) was used to visualise polyurethane foam-immobilised Citrobacter after challenging with La³⁺ and/or Cu²⁺ in citrate buffer supplemented with glycerol 2-phosphate. Extensive phosphatase-mediated bioaccumulation of LaPO₄ was observed but no evidence for deposition of Cu₃(PO₄)₂ was obtained by X-ray diffraction and proton-induced X-ray emission analyses. Image analysis showed that La³⁺/Cu²⁺ is a good model system to study the function of this biofilm reactor non-invasively by MRI.     

Avian ecological succession in the Amazon: A long‐term case study following experimental deforestation

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Detecting anthropogenic disturbance in tropical forests

Tropical forests are beleaguered by an array of threats driven by different scales of anthropogenic perturbations, which vary in the degree to which they can be detected by remote sensing. The extent of different patterns of cryptic disturbance often far exceeds the total area deforested, as shown by two recent studies on selective logging in Amazonia. Here, we discuss different forms of disturbance in Amazonian forests and question how much of the apparently intact forest in this region remains relatively undisturbed.     

Restriction-map variation with the yellow-achaete-scute region in five populations of Drosophila melanogaster

It has been proposed that the degree of recombination for a genomic region will affect the level of both nucleotide heterozygosity and the density of transposable elements. Both features of genomic diversity have been examined in a number of recent reports for regions undergoing relatively normal levels of recombination in Drosophila melanogaster. In this study the genomic variation associated with yellow-achaete- scute loci located at the tip of the X chromosome is examined by six- cutter restriction mapping. In this region, as usual for regions adjacent to telomeres, crossing-over is dramatically reduced, and published studies of visible mutants indicate extremely little restriction-map variation. Eight six-cutter restriction endonucleases were used to locate sequence variation in 14- and 16.5-kb regions in 109 lines sampled from North America, Africa, and Europe. The overall level of heterozygosity is estimated as 0.29%. Nine large insertions, all presumed to be transposable elements, were observed. Base-pair heterozygosity appears to be reduced compared with regions having normal levels of recombination. The estimated heterozygosity is much higher than reported in earlier studies of restriction-map variation among visible mutations in the complex. The incidence of large insertions is not elevated compared with that in other regions of the genome. This suggests that asymmetric synapsis and exchange is not an important mechanism for the elimination of transposable elements.      

A crisis in the making: responses of Amazonian forests to land use and climate change

At least three global-change phenomena are having major impacts on Amazonian forests: (1) accelerating deforestation and logging; (2) rapidly changing patterns of forest loss; and (3) interactions between human land-use and climatic variability. Additional alterations caused by climatic change, rising concentrations of atmospheric carbon dioxide, mining, overhunting and other large-scale phenomena could also have important effects on the Amazon ecosystem. Consequently, decisions regarding Amazon forest use in the next decade are crucial to its future existence.     

Effects of context on judgements of odor intensities in humans

This study evaluated whether the intensity of previously smelled odors could unintentionally influence the subsequent judgement of odor intensity. The predicted context effect was based on the adaptation- level theory. Before and 25 min after either WEAK or STRONG biasing odor concentrations, 51 subjects were required to rate the intensity of 10 different odor concentrations of California Orange Oil. After the WEAK bias, subjects judged the odor intensity as being stronger than they did after the STRONG bias. Thus the intensity of odors smelled 25 min earlier can unintentionally influence subsequent odor intensity judgement. The findings are discussed in the light of two alternative explanations, namely, a central implicit memory process and a stimulus- level-based change at the peripheral level.      

CLINICAL EXPERIENCE WITH CHLORPROPAMIDE

Seventy-eight patients with mild diabetes were treated with chlorpropamide in doses up to 1 gm. daily. Eight showed primary failure to respond and two showed an initial but not a sustained response. Patients whose diabetes was of recent onset and who had not been treated with insulin or a sulfonylurea, required smaller doses than the remainder except for a group of patients who had been diabetic for more than 15 years.The average dose for the 64 patients who took chlorpropamide for more than three months was 0.46 gm. per day. Serious side effects were uncommon and disappeared when the drug was stopped. One patient became jaundiced, one had a rash, and one showed granulocytopenia. Changes in liver function tests were seen in 17 out of 56 patients treated for more than three months and were correlated with the dosage of the drug and the duration of treatment.