Why use bubble-column bioreactors?

Among the plethora of bioreactors available for aerobic culture, bubble columns, which are composed of a cylindrical vessel fitted with a gas sparger, are gaining in use. The simple construction of bubble-column reactors makes them easy to maintain. In addition, it is possible to control the degree of shear, uniformly within the reactor, which is critical to the growth of plant and animal cells in particular. This article reviews in detail the hydrodynamic, heat and mass-transfer characteristics of bubble-column bioreactors - parameters that are important for industrial scale-up.     

‘Smart’ cards use biometrics

The combined usage of smart cards and biometrics has gained in popularity over the last two years. While smart cards themselves may be highly secure, many smart card suppliers are acknowledging the advantage that biometrics can bring to their products by linking the card to the owner. Meanwhile, an advantage to the biometric industry is a privacy-friendly medium to carry its templates. A number of high profile applications have helped push the convergence of the technologies, but a remaining question is how far this convergence will actually go, with sensor-on-card products just around the corner?     

Drivers of land use efficiency and trade embodied biomass use of Finland 2000–2010

Globally human pressure on the biosphere is increasing, in spite of increases in land use efficiency. The pressure consists of land use and potential degradation. Human appropriation of net primary production (HANPP) is emerging as an indicator, which combines the dual aspects of biomass use and land degradation. Recently HANPP has been used to map the increasing dependence of European countries on biomass imports and the conflicting processes of increased yields and increased consumption. However large overview studies could be complemented with indepth analysis into the causes of changes in individual countries and economic sectors. This allows the analysis of the macroeconomic drivers of change and the responses in sectors to these drivers. In this study we decomposed the HANPP of Finland including imports for the years 2000–2010 using IPAT and applied input-output analysis to look at sectoral land use efficiency in that time period. Finland is a country with intensive biomass trade, and with a very high per capita HANPP. During the study period the sum of domestic and embodied in imports HANPP of the Finnish economy decreased from 76 Mt C/a to 62 Mt C/a (−1% annually on average), while the HANPP related to imports increased from 12 Mt C/a to 14 Mt C/a. The overall trend was that of declining exports and increasing domestic consumption. Of the economic sectors wood harvesting and processing dominated HANPP results, followed by residential construction, animal production and energy supply. In terms of HANPP, most of these decreased, but housing and energy production increased considerably from 2002 to 2010. At the macroeconomic level domestic biomass use per unit of value added decreased (−2.2%/a) as did the amount of HANPP per unit of biomass (−1.1%/a) reflecting increased economic efficiency in land use. In contrast, GDP/capita (+1.3%/a), population (+0.4%) and the share of outsourced HANPP (+0.6%) resulted in increased consumption-based HANPP (from 21 Mt C in 2002 to 27 Mt C in 2010). Our results underline the importance of including international trade and consumption in interpreting overall change in regional HANPP.     

Ecology – a science put to use

There is no lack of pretext for reviewing historically how ecologists have striven to gain the respect of scholars in their own and other fields, and to demonstrate the wider public-utility of their science. If self-serving, in terms of securing the scope and resources required to advance their studies in ecology, such activities have also been encouraged, and indeed commissioned, in the belief that a greater awareness and understanding of the natural world is essential for human wellbeing. Illustrative material is drawn from the British experience.     

Can plants use entomopathogens as bodyguards?

For 20 years, ecologists have been gathering evidence in support of the hypothesis that plants can use insect natural enemies such as predators and parasitoids as bodyguards to protect themselves from herbivory, but entomopathogens have escaped this consideration. We extend the bodyguard hypothesis to ask whether plants can use entomopathogens as bodyguards. We first discuss the evolutionary context of such tritrophic interactions and then categorize possible mechanisms as: (1) maintaining a population of bodyguards on the plant surface, (2) increasing contact rates between insect host and pathogen and (3) increasing the susceptibility of the host. We explore these mechanisms further, examining published studies for evidence for the hypothesis. We then discuss potential costs to the plant of promoting pathogens as bodyguards which may include a reduction in the efficiency of other "bodyguard" species, the incidental promotion of plant pathogens and the risk of entomopathogens developing phytopathogenicity. Aside from our intention to stimulate the testing of the bodyguard hypothesis with entompathogens and to provide a conceptual framework for this, we hope to bring evolutionary ecology and insect pathology closer together.     

How do we use language? Shared patterns in the frequency of word use across 17 world languages

We present data from 17 languages on the frequency with which a common set of words is used in everyday language. The languages are drawn from six language families representing 65 per cent of the world's 7000 languages. Our data were collected from linguistic corpora that record frequencies of use for the 200 meanings in the widely used Swadesh fundamental vocabulary. Our interest is to assess evidence for shared patterns of language use around the world, and for the relationship of language use to rates of lexical replacement, defined as the replacement of a word by a new unrelated or non-cognate word. Frequencies of use for words in the Swadesh list range from just a few per million words of speech to 191 000 or more. The average inter-correlation among languages in the frequency of use across the 200 words is 0.73 (p < 0.0001). The first principal component of these data accounts for 70 per cent of the variance in frequency of use. Elsewhere, we have shown that frequently used words in the Indo-European languages tend to be more conserved, and that this relationship holds separately for different parts of speech. A regression model combining the principal factor loadings derived from the worldwide sample along with their part of speech predicts 46 per cent of the variance in the rates of lexical replacement in the Indo-European languages. This suggests that Indo-European lexical replacement rates might be broadly representative of worldwide rates of change. Evidence for this speculation comes from using the same factor loadings and part-of-speech categories to predict a word's position in a list of 110 words ranked from slowest to most rapidly evolving among 14 of the world's language families. This regression model accounts for 30 per cent of the variance. Our results point to a remarkable regularity in the way that human speakers use language, and hint that the words for a shared set of meanings have been slowly evolving and others more rapidly evolving throughout human history.     

Veneers and plywood—their manufacture and use

Two closely related industries that depend, to a major degree, upon domestic sources of red gum, Douglasfir, black walnut, red and white oaks, sugar maple, Sitka spruce, Ponderosa pine and Port Orford cedar; and upon foreign sources of mahogany, rosewood, zebrawood, avodiré, bossé, ebony and other exotic species.     

Why do nitric oxide synthases use tetrahydrobiopterin?

We are combining stopped-flow, stop-quench, and rapid-freezing kinetic methods to help clarify the unique redox roles of tetrahydrobiopterin (H(4)B) in NO synthesis, which occurs via the consecutive oxidation of L-arginine (Arg) and N-hydroxy-L-arginine (NOHA). In the Arg reaction, H(4)B radical formation is coupled to reduction of a heme Fe(II)O(2) intermediate. The tempo of this electron transfer is important for coupling Fe(II)O(2) formation to Arg hydroxylation. Because H(4)B provides this electron faster than can the NOS reductase domain, H(4)B appears to be a kinetically preferred source of the second electron for oxygen activation during Arg hydroxylation. A conserved Trp (W457 in mouse inducible NOS) has been shown to influence product formation by controlling the kinetics of H(4)B electron transfer to the Fe(II)O(2) intermediate. This shows that the NOS protein tunes H(4)B redox function. In the NOHA reaction the role of H(4)B is more obscure. However, existing evidence suggests that H(4)B may perform consecutive electron donor and acceptor functions to reduce the Fe(II)O(2) intermediate and then ensure that NO is produced from NOHA.     

Die Knickschwänze der Mäuse

Ohne Zusammenfassung     

On the correct use of ‘data’

Acknowledgement  Thanks are due to Drs. Paul Johnston (P.Johnston@ exeter.ac.uk) and E. William Beese (ebeese@t-online.de) for kindly providing dictionary definitions and for sharing their thoughts about the correct use of ‘data’.     

What's so special about human tool use?

Evidence suggests homologies in parietofrontal circuits involved in object prehension among humans and monkeys. Likewise, tool use is known to induce functional reorganization of their visuotactile limb representations. Yet, humans are the only species for whom tool use is a defining and universal characteristic. Why? Comparative studies of chimpanzee tool use indicate that critical differences are likely to be found in mechanisms involved in causal reasoning rather than those implementing sensorimotor transformations. Available evidence implicates higher-level perceptual areas in these processes.     

Do Arctic waders use adaptive wind drift?

We analysed five data sets of flight directions of migrating arctic waders in relation to winds, recorded by tracking radar and optical range finder, in order to find out if these birds compensate for wind drift, or allow themselves to be drifted by winds. Our purpose was to investigate whether arctic waders use adaptive wind drift strategies or not. The data sets were collected in Siberia (two sets) and Canada during post-breeding (autumn) migration, and in Mauritania and South Sweden during pre-breeding (spring) migration. Both significant drift and compensation effects were found in three of the data sets, Canada, Mauritania and South Sweden. Almost no compensation was found in birds departing in easterly directions from the Siberian tundra (complete drift), while no drift effect was found in birds departing in westerly directions (complete compensation). There were indications that at least some populations of waders may use an adaptive drift strategy consisting of drift at high altitude and/or in high wind speed combined with compensation at low altitude and/or in lower wind speeds, but support for this idea was rather weak and not consistent. Our results were instead more in accordance with the adaptive drift theory that predicts initial drift during the migratory journey, followed by compensation during later stages as the birds are approaching their destinations. Such a strategy implies that arctic waders, at least adult birds, have the capacity of true navigation. A comparison with earlier studies of migrating arctic waders from different parts of the world show that all results so far may be interpreted in accordance with this general adaptive drift strategy. An element of non-adaptive drift can, however, not be completely ruled out.     

Die symbiose der läuse und federlinge

Ohne Zusammenfassung