Golden Eagle ( Aquila chrysaetos ) population ecology in eastern Utah

Golden Eagle population ecology was studied from 1982 to 1992 in eastern Utah where over 47% of 233 territories monitored during the study period were active. Golden Eagle use of four habitat types was compared. Talus territories were used less often than expected; valley, aspen-conifer, and pinyon-juniper territories were used as expected. Number of young produced per territory averaged 0.612 and was correlated with rabbit abundance. Observations on the impacts of coal mining at two locations are discussed.     

Beavers indirectly enhance the growth of Russian olive and tamarisk along eastern Montana rivers

Russian olive and tamarisk are introduced woody plants invading western North American riparian communities. Beavers can play an important role in structuring these communities by removing the dominant cottonwood trees. Our study explored the way in which beavers interact with cottonwood, Russian olive, and tamarisk along 4 rivers on the Great Plains of eastern Montana. We sampled cottonwood stands that supported populations of 1 or both exotic species, recording beaver damage and density in addition to size and age of cottonwood, Russian olive, and tamarisk. In stands where beaver had been present, they felled an average of 80% of cottonwood trees while rarely using Russian olive or tamarisk. Beaver foraging was apparent in nearly 90% of stands within 50 m of the river channel but only 21% of stands farther away, creating a sunny corridor along the river channel that may increase the invasive potential of Russian olive and tamarisk. Growth rates of both Russian olive and tamarisk were substantially higher where beavers had reduced the cottonwood canopy cover. Managers wishing to reintroduce beavers should consider the potential effect on invasive exotic plants.     

Cicero's demarcation of science: A report of shared criteria

The problem of establishing intensional criteria to demarcate science from non-science, and in particular science from pseudoscience, received a great amount of attention in the 20th century philosophy of science. It remains unsolved. This article compares demarcation criteria found in Marcus Tullius Cicero’s rejection of genethliac astrology and other pseudo-divinatory techniques in his De divinatione (44 BCE) with criteria advocated by a broad selection of modern philosophers of science and other specialists in science studies. Remarkable coincidences across two millennia are found on five basic criteria, which hints at a certain historical stability of some of the most fundamental features of a concept of “science” broadly construed.     

Extracellular wildtype and mutant SOD1 induces ER–Golgi pathology characteristic of amyotrophic lateral sclerosis in neuronal cells

Amyotrophic lateral sclerosis (ALS) is a fatal and rapidly progressing neurodegenerative disorder and the majority of ALS is sporadic, where misfolding and aggregation of Cu/Zn-superoxide dismutase (SOD1) is a feature shared with familial mutant-SOD1 cases. ALS is characterized by progressive neurospatial spread of pathology among motor neurons, and recently the transfer of extracellular, aggregated mutant SOD1 between cells was demonstrated in culture. However, there is currently no evidence that uptake of SOD1 into cells initiates neurodegenerative pathways reminiscent of ALS pathology. Similarly, whilst dysfunction to the ER–Golgi compartments is increasingly implicated in the pathogenesis of both sporadic and familial ALS, it remains unclear whether misfolded, wildtype SOD1 triggers ER–Golgi dysfunction. In this study we show that both extracellular, native wildtype and mutant SOD1 are taken up by macropinocytosis into neuronal cells. Hence uptake does not depend on SOD1 mutation or misfolding. We also demonstrate that purified mutant SOD1 added exogenously to neuronal cells inhibits protein transport between the ER–Golgi apparatus, leading to Golgi fragmentation, induction of ER stress and apoptotic cell death. Furthermore, we show that extracellular, aggregated, wildtype SOD1 also induces ER–Golgi pathology similar to mutant SOD1, leading to apoptotic cell death. Hence extracellular misfolded wildtype or mutant SOD1 induce dysfunction to ER–Golgi compartments characteristic of ALS in neuronal cells, implicating extracellular SOD1 in the spread of pathology among motor neurons in both sporadic and familial ALS.     

Judgement in learning‐curve forecasting: a laboratory study

This study investigates whether human judgement can be of value to users of industrial learning curves, either alone or in conjunction with statistical models. In a laboratory setting, it compares the forecast accuracy of a statistical model and judgemental forecasts, contingent on three factors: the amount of data available prior to forecasting, the forecasting horizon, and the availability of a decision aid (projections from a fitted learning curve). The results indicate that human judgement was better than the curve forecasts overall. Despite their lack of field experience with learning curve use, 52 of the 79 subjects outperformed the curve on the set of 120 forecasts, based on mean absolute percentage error. Human performance was statistically superior to the model when few data points were available and when forecasting further into the future. These results indicate substantial potential for human judgement to improve predictive accuracy in the industrial learning‐curve context. Copyright © 1999 John Wiley & Sons, Ltd.     

Large-scale genetic fine mapping and genotype-phenotype associations implicate polymorphism in the IL2RA region in type 1 diabetes

Genome-wide association studies are now identifying disease-associated chromosome regions. However, even after convincing replication, the localization of the causal variant(s) requires comprehensive resequencing, extensive genotyping and statistical analyses in large sample sets leading to targeted functional studies. Here, we have localized the type 1 diabetes (T1D) association in the interleukin 2 receptor alpha (IL2RA) gene region to two independent groups of SNPs, spanning overlapping regions of 14 and 40 kb, encompassing IL2RA intron 1 and the 5' regions of IL2RA and RBM17 (odds ratio = 2.04, 95% confidence interval = 1.70-2.45; P = 1.92 x 10(-28); control frequency = 0.635). Furthermore, we have associated IL2RA T1D susceptibility genotypes with lower circulating levels of the biomarker, soluble IL-2RA (P = 6.28 x 10(-28)), suggesting that an inherited lower immune responsiveness predisposes to T1D.     

SIRT6 is a histone H3 lysine 9 deacetylase that modulates telomeric chromatin

The Sir2 deacetylase regulates chromatin silencing and lifespan in Saccharomyces cerevisiae. In mice, deficiency for the Sir2 family member SIRT6 leads to a shortened lifespan and a premature ageing-like phenotype. However, the molecular mechanisms of SIRT6 function are unclear. SIRT6 is a chromatin-associated protein, but no enzymatic activity of SIRT6 at chromatin has yet been detected, and the identity of physiological SIRT6 substrates is unknown. Here we show that the human SIRT6 protein is an NAD+-dependent, histone H3 lysine 9 (H3K9) deacetylase that modulates telomeric chromatin. SIRT6 associates specifically with telomeres, and SIRT6 depletion leads to telomere dysfunction with end-to-end chromosomal fusions and premature cellular senescence. Moreover, SIRT6-depleted cells exhibit abnormal telomere structures that resemble defects observed in Werner syndrome, a premature ageing disorder. At telomeric chromatin, SIRT6 deacetylates H3K9 and is required for the stable association of WRN, the factor that is mutated in Werner syndrome. We propose that SIRT6 contributes to the propagation of a specialized chromatin state at mammalian telomeres, which in turn is required for proper telomere metabolism and function. Our findings constitute the first identification of a physiological enzymatic activity of SIRT6, and link chromatin regulation by SIRT6 to telomere maintenance and a human premature ageing syndrome.     

Human adenosine deaminase and chromosome 20

Summary In patients exhibiting in marrow cells deletion of the long arm of chromosome 20, the specific activities of adenosine deaminase in cells of the peripheral blood are normal. This suggests that the gene for adenosine deaminase is not localized to the distal segment of the long arm of this chromosome.This work was supported by Grants from the National Health and Medical Research Council of Australia and the Anti-Cancer Council of Victoria.     

Orotic acid prevents changes in cardiac sarcolemmal glycoproteins and contractility associated with muscular dystrophy in hamsters

Summary Orotic acid included in the diet of cardiomyopathic hamsters during the myolytic phase of the disease (30–60 days of age) prevented the reduction in cardiac sarcolemmal sialic acid, calcium binding, sialyltransferase activity and contractile activity associated with the cardiomyopathy.This work was supported by research grants from the MRC of Canada, the Muscular Dystrophy Association of Canada and the Nova Scotia Heart Foundation. I thank Dr Peter E. Dresel for his encouragement and Ms Jane Benjamin and Mr Steven Couban for their technical assistance.