Statistically Stable Estimates of Variance in Radioastronomical Observations as Tools for RFI Mitigation

A selection of statistically stable (robust) algorithms for data variance calculating has been made. Their properties have been analyzed via computer simulation. These algorithms would be useful if adopted in radio astronomy observations in the presence of strong sporadic radio frequency interference (RFI). Several observational results have been presented here to demonstrate the effectiveness of these algorithms in RFI mitigation

Isoelectric focusing studies of A2/1957 influenza neuraminidase and its subunits

Purified A2/1957 influenza neuraminidase (mucopolysaccharide N-acetylneuraminylhydrolase, EC 3.2.1.18) and its subunits were examined by isoelectric focusing (`electrofocusing') in sucrose gradients. Native neuraminidase contained enzymically active components with isoelectric points (pI) of about 5.2, 5.35, 5.5, 5.8, 6.2 and 6.5. The major components were at about pI 5.5 and 5.8. Neuraminidase was dissociated into subunits, whose sulfhydryl groups were blocked with iodo[14C]acetamide. 80% of isotope label incorporated was present in a single size of subunits with a molecular weight (Mr) of 51 000 as determined by sodium dodecyl sulfate acrylamide gel electrophoresis. The pI of denatured subunits was about 3.6 to 4.4. 14C-labelled peptides of tryptically digested neuraminidase had predominantly acidic isoelectric points. Results are consistent that the pI of native neuraminidase is about 1.5-2 pH units higher than the pI of its structural subunits, suggesting that side chain carboxyl groups are conformationally masked in the native enzyme, and that isoelectric heterogeneity of neuraminidase may result from conformation-dependent variations in the acid-base dissociation of these groups.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33847/1/0000105.pd

The preparation and properties of 14C-carboxamido-methylated subunits from A2/1957 influenza neuraminidase

A2/1957 influenza neuraminidase (mucopolysaccharide N-acetylneuraminylhydrolase, EC 3.2.1.18) was purified 15-fold from a recombinant virus, with about 25% overall yield of enzymic activity. Neuraminidase contained glucosamine, and a high proportion of serine and threonine. The partial specific volume was 0.713 cm3/g. Reduced neuraminidase was isotopically labeled in vitro by reaction with iodo[14C]-acetamide. When carboxamidomethylated in the absence of urea, enzymically inactive labeled material was obtained with a maximum size similar to native neuraminidase. When carboxamidomethylated in the presence of 6 M urea, labeled, dissociated subunits were obtained that did not associate or regain enzymic activity on removal of urea. The molecular weight of dissociated subunits was determined by sedimentation-diffusion methods as 50 000-54 000, and by sodium dodecyl sulfate-acrylamide gel electrophoresis as about 50 000. Thus native neuraminidase (mol. wt. about 200 000) is probably a tetramer. Neuraminidase contained about 21 cysteine residues per subunit. These appear to be present as disulfide bonds in the native enzyme.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34154/1/0000440.pd

Robust retention and transfer of tool construction techniques in chimpanzees (Pan troglodytes)

Long-term memory can be critical to a species’ survival in environments with seasonal and even longer-term cycles of resource availability. The present, longitudinal study investigated whether complex tool behaviors used to gain an out-of-reach reward, following a hiatus of about 3 years and 7 months since initial experiences with a tool use task, were retained and subsequently executed more quickly by experienced than by naïve chimpanzees. Ten of the 11 retested chimpanzees displayed impressive long-term procedural memory, creating elongated tools using the same methods employed years previously, either combining 2 tools or extending a single tool. The complex tool behaviors were also transferred to a different task context, showing behavioral flexibility. This represents some of the first evidence for appreciable long-term procedural memory, and improvements in the utility of complex tool manufacture in chimpanzees. Such long-term procedural memory and behavioral flexibility have important implications for the longevity and transmission of behavioral traditions

Chimpanzees demonstrate individual differences in social information use

Studies of transmission biases in social learning have greatly informed our understanding of how behaviour patterns may diffuse through animal populations, yet within-species inter-individual variation in social information use has received little attention and remains poorly understood. We have addressed this question by examining individual performances across multiple experiments with the same population of primates. We compiled a dataset spanning 16 social learning studies (26 experimental conditions) carried out at the same study site over a 12-year period, incorporating a total of 167 chimpanzees. We applied a binary scoring system to code each participant’s performance in each study according to whether they demonstrated evidence of using social information from conspecifics to solve the experimental task or not (Social Information Score—‘SIS’). Bayesian binomial mixed effects models were then used to estimate the extent to which individual differences influenced SIS, together with any effects of sex, rearing history, age, prior involvement in research and task type on SIS. An estimate of repeatability found that approximately half of the variance in SIS was accounted for by individual identity, indicating that individual differences play a critical role in the social learning behaviour of chimpanzees. According to the model that best fit the data, females were, depending on their rearing history, 15–24% more likely to use social information to solve experimental tasks than males. However, there was no strong evidence of an effect of age or research experience, and pedigree records indicated that SIS was not a strongly heritable trait. Our study offers a novel, transferable method for the study of individual differences in social learning

Perspectives of an international sample of adults with trichotillomania on the acceptability and feasibility of an asynchronous qualitative email interview method

Purpose: Trichotillomania (TTM) is characterised by the recurrent pulling out of one’s own hair, resulting in hair loss. It is a poorly understood disorder with no consensus on aetiology or epidemiology. Nested within a larger qualitative study exploring a wide range of TTM topics; the aim of this paper is to report and consider participant views on the acceptability and feasibility of the asynchronous email interview method. Method: Cross-cultural qualitative research on TTM is sparse; therefore, an international qualitative study with a geographically diverse sample was conducted using an asynchronous email interview method. Results: Participant perspectives highlighted three themes related to the study method: the value in creating personal connections, cathartic reflections, and perceived strengths and weaknesses. This paper highlights the potential of the asynchronous email interview method for sustaining remote research across multiple locations, using a sample of 20 adults with TTM (18-55 years) from 15 different countries. Conclusions: This was an acceptable and feasible method for data collection, facilitating remote access while yielding rich data from an often hidden and hard-to-reach population

Flocculation of influenza virus by specific anti-neuraminidase antibody

1. Flocculation of purified preparations of influenza virus has been demonstrated to occur in the presence of low dilutions of specific anti-neuraminidase sera. High dilutions of the sera caused microscopic aggregation of virions. It is suggested that the effects of anti-neuraminidase antibody on the replication of influenza virus observed in vitro could be caused by antibody binding virions to infected cells, rather than by inhibition of neuraminidase enzymic activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41680/1/705_2005_Article_BF01253756.pd

Assessment of pollution risk ascribed to Santa Margarida Military Camp activities (Portugal)

Santa Margarida Military Camp (S.M.M.C.) is the only one Portuguese military training area, including firing ranges for tactical military manoeuvres of mechanised divisions. For this reason, various negative effects on the environment were expected due to the military activities, as the Military Camp’s area is classified as a high vulnerability area to pollution of its multilayer porous aquifers. The aim of this study was to identify and characterise local/regional geochemical impacts caused by the continuing military training activities performed at S.M.M.C. in the course of 52 years. An overview of the geochemical research issues as a basis for risk assessment is presented. A special attention has been put on the quality of local and regional surface waters, shallow groundwaters and groundwaters. Local soils and sediments as well as fragments of shells and bullets were sampled and analysed. The results so far obtained, indicated that none pollution effects were a consequence of the military training activities. Till now, the geochemical signatures such as, high levels of K, Cl and NO3 in waters, detected in particular sites, should be faced as tracers of diffuse pollution ascribed to urban waste disposal and cattle breading

Laboratory properties of cold-adapted influenza B live vaccine strains developed in the US and USSR, and their B/Ann Arbor/1/86 cold-adapted reassortant vaccine candidates

The adaptation of two influenza B strains (B/Leningrad/14/55 and B/Ann Arbor/1/66) to replication at 25[deg]C is described. Comparison of the two viruses indicates that both also exhibit temperature sensitive phenotypes, although that of the virus B/Leningrad/14/55 is less pronounced. When inoculated into ferrets both viruses replicate well in the trachea, but only the B/Leningrad/14/55 cold-adapted virus replicates in the lungs. This virus exhibited a moderate level of attenuation in the animals, in contrast to the B/Ann Arbor/1/66 cold-adapted virus, which was fully attenuated. Reassortant viruses deriving the surface antigens of the contemporary wild type virus B/Ann Arbor/1/86 and most or all of their other genes, from one or other cold-adapted parent, were virtually indistinguishable from their respective cold-adapted parents. The B/Leningrad/14/55 reassortant was slightly more attenuated than its cold-adapted parent in ferrets. These studies extend knowledge of the properties of viruses used to prepare experimental live influenza B human vaccines.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28728/1/0000554.pd