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Model and Metaphor in Social Anthropology.

A Zambezia article on the use of model and metaphor.The intention in this paper is to review the use of model and metaphor in one social science, social anthropology; to come in this context to a better understanding of the working distinction between these terms; and finally to appraise their usefulness and comprehensiveness for this discipline

Isolating novel antibodies against difficult targets using next generation antibody phage display

Phage display bypasses the immune response by bringing the entire immune repertoire to a target antigen, in vitro. The coupling of antibody phage display and next generation sequencing (NGS) has the potential to revolutionise the discovery of novel antibodies. In this study, next generation antibody phage display (NGAPD) strategies were devised to identify novel antibodies against conformational epitopes on the enzyme phytase, and against the hapten phytic acid. These were notably difficult targets and previous immunisation attempts for phytic acid have not demonstrated any immune response for hybridoma or the production of immune phage display libraries. This study used naïve human scFv and camelid VHH phage display libraries and it was therefore more difficult to identify potential binders due to a lack of bias towards the targets within a high level of antibody diversity. Following phage panning, the read depth provided by NGS facilitates the identification of novel ligands from within a diverse sub-library, and thus the study also aimed to optimise the use of NGS with naïve phage display libraries. The NGS approach was used in comparison with conventional colony picking. The colony picking approach successfully identified phage-fusion binders against the three targets, however when expressed as antibody-MBP fusions the binding activities were lost. The NGS data analysis involved ranking candidates using a Z score followed by further, highly stringent sorting analyses designed to remove nonspecific ligands. Major challenges involved rescuing scFv candidates from their sub-libraries; this was later resolved with the use of the camelid VHH library that uses a single antibody framework. The NGAPD concluded with a range of NGS candidates synthesised from the final VHH experiment. The candidates were cloned in a single step into a pMAL expression system using inverse PCR. Finally, the NGS candidates were expressed as MBP fusions; however no binding activity was detected. The final section of the study considered alternative bioinformatics analysis strategies for NGS data that have been used in the literature for both antibodies and peptides and also suggested novel enrichment profiles as a means of identifying selection dependant ligands. The VHH NGS data was reassessed based solely on candidate frequency and enrichment throughout panning. A selection of antibody candidates were identified by both bioinformatics methods for phytase, suggesting that the original NGS analysis strategy was successfully identifying promising candidates that were more likely to be conformation specific

Personal Computing in the 1990s

Personal computers have changed the way that business is conducted in today\u27s office. Every position in a company is affected by the use of personal computers from secretaries to top level management. Tasks and job duties are performed more easily thereby increasing productivity. Personal computers in the 1990s will be networked via LANs to other personal computers, minicomputers and mainframes to enhance people\u27s abilities and allow them to perform their jobs better. With the increased use of LANs, many LAN productivity applications wUl be utilized that will also increase productivity. E-Mail and groupware software will allow people to interact with each other without leaving their offices. These systems will reduce the amount of needless paperwork and time spent in meetings. The 1990s will also see an increase in the use of portable computers because of the small size and increased expansion capabilities, making it easy for users to tap into the network. These portables will allow employees to work at home and transmit any data to the office. Also, these portables will increase the productivity of many field applications. With the new advancements in personal computing, managers in the 1990s will need to understand these PC-based systems and how they impact individuals in the workplace

Weakening the subjective sensation of own hand ownership does not interfere with rapid finger movements

When we perform a movement we generally have a clear distinction between which parts of the world constitute our body and which parts do not. However, how the sense of ownership over our body supports movement is not yet fully understood. We aimed to see whether a sense of ownership over the hand supports the performance of rapid hand movements. In three experiments (n = 48, n = 30, n = 24), we presented participants with congruent and incongruent visuotactile and visuoproprioceptive information regarding their own hand. In keeping with previous experiments, multisensory disintegration resulted in a reduction in the subjective sensation of ownership over the hand, as reflected in questionnaire responses. Following sensory stimulation, participants were required to rapidly abduct their index finger whilst the movement was tracked. We examined the hypothesis that, should a sense of ownership over the limb be necessary for generating rapid movements with that limb, reaction time would increase when hand ownership was reduced, whilst the acceleration and velocity of the movement would decrease. We observed that reductions in own hand ownership did not interfere with rapid index finger abduction, suggesting that the motor system may not be reliant on a subjective sense of ownership over the body in order to generate movement

Hoverflies are imperfect mimics of wasp colouration

Many Batesian mimics are considered to be inaccurate copies of their models, including a number of hoverfly species which appear to be poor mimics of bees and wasps. This inaccuracy is surprising since more similar mimics are expected to deceive predators more frequently and therefore have greater survival. One suggested explanation is that mimics which appear inaccurate to human eyes may be perceived differently by birds, the probable agents of selection. For example, if patterns contain an ultra-violet (UV) component, this would be visible to birds but overlooked by humans. So far, indirect comparisons have been made using human and bird responses to mimetic stimuli, but direct colour measurements of mimetic hoverflies are lacking. We took spectral readings from a wide range of hoverfly and wasp patterns. They show very low reflectance in the UV range, and do not display any human-invisible colour boundaries. We modelled how the recorded spectra would be perceived by both birds and humans. While colour differences between wasps and hoverflies are slightly more distinct according to human visual abilities, bird vision is capable of discriminating the two taxa in almost all cases. We discuss a number of factors that might make the discrimination task more challenging for a predator in the field, which could explain the apparent lack of selection for accurate colour mimicry

Distance transform: a tool for the study of animal colour patterns

Summary The information in animal colour patterns plays a key role in many ecological interactions; quantification would help us to study them, but this is problematic. Comparing patterns using human judgement is subjective and inconsistent. Traditional shape analysis is unsuitable as patterns do not usually contain conserved landmarks. Alternative statistical approaches also have weaknesses, particularly as they are generally based on summary measures that discard most or all of the spatial information in a pattern. We present a method for quantifying the similarity of a pair of patterns based on the distance transform of a binary image. The method compares the whole pattern, pixel by pixel, while being robust to small spatial variations among images. We demonstrate the utility of the distance transform method using three ecological examples. We generate a measure of mimetic accuracy between hoverflies (Diptera: Syrphidae) and wasps (Hymenoptera) based on abdominal pattern and show that this correlates strongly with the perception of a model predator (humans). We calculate similarity values within a group of mimetic butterflies and compare this with proposed pairings of Müllerian comimics. Finally, we characterise variation in clypeal badges of a paper wasp (Polistes dominula) and compare this with previous measures of variation. While our results generally support the findings of existing studies that have used simpler ad hoc methods for measuring differences between patterns, our method is able to detect more subtle variation and hence reveal previously overlooked trends

Subcortical contributions to the sense of body ownership

The sense of body ownership (i.e., the feeling that our body or its parts belong to us) plays a key role in bodily self-consciousness and is believed to stem from multisensory integration. The development of experimental paradigms that allow the controlled manipulation of body ownership in laboratory settings, such as the rubber hand illusion, provide an effective tool to investigate the malleability of the sense of body ownership and the boundaries distinguishing self and other. Neuroimaging studies on body ownership converge on the involvement of several cortical regions, including the premotor cortex and posterior parietal cortex. However, relatively less attention has been paid to subcortical structures that may also contribute to body ownership perception, such as the cerebellum and putamen. Here, on the basis of neuroimaging and neuropsychological observations, we provide an overview of relevant subcortical regions and consider their potential role in generating and maintaining a sense of ownership over the body. We also suggest novel avenues for future research targeting the role of subcortical regions in making sense of the body as our own

Seasonal contribution of terrestrial organic matter and biological oxygen demand to the Baltic Sea from three contrasting river catchments

To examine the potential influence of terrestrially derived DOM on the Baltic Sea, a year-long study of dissolved organic matter (DOM) was performed in three river catchments in Sweden. One catchment drains into the Bothnian Sea, while two southern catchments drain into the Baltic proper. Dissolved organic carbon (DOC) concentrations were positively correlated with discharge from forested catchments over the year. While the overall concentrations of DOC were several times higher in the southern two catchments, higher discharge in the northern catchment resulted in the annual loadings of DOC being on the same order of magnitude for all three catchments. Biological oxygen demand (BOD) was used as a proxy for the lability of carbon in the system. The range of BOD values was similar for all three catchments, however, the ratio of BOD to DOC (an indication of the labile fraction) in Ume river was four times higher than in the southern two catchments. Total annual BOD loading to the Baltic Sea was twice as high in the northern catchment than in the two southern catchments. Lower winter temperatures and preservation of organic matter in the northern catchment combined with an intense spring flood help to explain the higher concentrations of labile carbon in the northern catchment. Lower lability of DOM as well as higher colour in the southern catchments suggest that wetlands (i.e. peat bogs) may be the dominant source of DOM in these catchments, particularly in periods of low flow. With climate change expected to increase precipitation events and temperatures across the region, the supply and quality of DOM delivered to the Baltic Sea can also be expected to change. Our results indicate that DOM supply to the Baltic Sea from boreal rivers will be more stable throughout the year, and potentially have a lower bioavailability