Aspirated capacitor measurements of air conductivity and ion mobility spectra

Measurements of ions in atmospheric air are used to investigate atmospheric electricity and particulate pollution. Commonly studied ion parameters are (1) air conductivity, related to the total ion number concentration, and (2) the ion mobility spectrum, which varies with atmospheric composition. The physical principles of air ion instrumentation are long-established. A recent development is the computerised aspirated capacitor, which measures ions from (a) the current of charged particles at a sensing electrode, and (b) the rate of charge exchange with an electrode at a known initial potential, relaxing to a lower potential. As the voltage decays, only ions of higher and higher mobility are collected by the central electrode and contribute to the further decay of the voltage. This enables extension of the classical theory to calculate ion mobility spectra by inverting voltage decay time series. In indoor air, ion mobility spectra determined from both the novel voltage decay inversion, and an established voltage switching technique, were compared and shown to be of similar shape. Air conductivities calculated by integration were: 5.3 +- 2.5 fS/m and 2.7 +- 1.1 fS/m respectively, with conductivity determined to be 3 fS/m by direct measurement at a constant voltage. Applications of the new Relaxation Potential Inversion Method (RPIM) include air ion mobility spectrum retrieval from historical data, and computation of ion mobility spectra in planetary atmospheres.Comment: To be published in Review of Scientific Instrument

Determinants of Knowledge and Technology Transfer Activities Between Firms and Science Institutions in Switzerland: An Analysis Based on Firm Data

This study explores the factors determining the propensity of Swiss firms to interact with public science institutions in Switzerland (universities and other research institution), i.e. to get involved in knowledge and technology transfer (KTT) activities in order to gain new tacit and/or codified scientific knowledge in research fields which are relevant for their own innovation activities. We are especially interested in the different forms of this interaction, not only through joint research projects but also through training, recruitment of qualified R&D personnel, jointly supervised master theses and PhDs, consulting and so on. The data used in this study were collected in the course of a survey among Swiss enterprises. The new elements that this paper adds to empirical literature are, first, the analysis of a wide spectrum of KTT activities covering not only research co-operation agreements between firms and science institutions but also general informational and educational activities (transfer of tacit knowledge), joint use of technical infrastructure and consulting. Although such additional activities seem to be an important part of KTT activities, they have been neglected in most studies. Second, a further important element is the explicit consideration of a series of relevant motives and obstacles as determinants of KTT which contribute significantly to the econometric explanation of firms' propensity to overall KTT activities as well as to several forms of KTT activities. Third, some insights are gained with respect to the differences between manufacturing and service firms in transacting with science institutions. This is the first Swiss firm-level study on this matter

Complementarities between Barriers to Innovation: Data Evidence from Poland

This paper investigates the barriers to innovation perceived by Polish manufacturing firms. It refers to the heterogeneity of innovation active firms. We introduce a taxonomy of innovative firms based on the frequency with which they introduce commercialised innovations using data from both CIS4 (for 2002-2004) and CIS5 (2004-2006). Two groups of innovation-active firms are distinguished: those which introduced innovation in both periods covered by both CIS (which we call persistent innovators) and those which introduced innovation either in CIS4 or CIS5 (which we call occasional innovators). We use a four step analysis covering binary correlations, Principal Component Analysis, probit model and correlations of disturbances. Two types of explanatory variables describing firms' characteristics and innovation inputs used are considered. The paper shows that there are considerable differences in sensitivities to the perception of innovation barriers and in complementarities among barriers between persistent and occasional innovators. In the case of occasional innovators, a kind of innovation barrier chain is observed. This has an impact on differences in the frequency of innovation activities between the two groups of innovators and results in a diversification of innovators

Pain shared, pain halved? Cooperation as a coping strategy for innovation barriers

The paper analyses the relationship between the perception of barriers to innovation and the firm’s propensity to cooperate to mitigate their effect. First, we look at whether cooperation with research organizations or private firms is associated with experiencing different types of barriers, for example, financial constraints, lack of human capital or uncertain market demand. Second, we test whether experiencing several types of barriers simultaneously has a super-modular effect on the propensity to cooperate tout court, and the choice of cooperation partner. We find that having to face a single, specific constraint leads to firms ‘sharing the pain’ with cooperation partners—both research organization and other firms. However, the results of a super-modularity test show that having to cope with different barriers is a deterrent to establishing cooperation agreements, especially when firms lack finance, adequate skills and information on technology or markets. The paper adds to the innovation literature by identifying the factors associated with firms’ coping with different barriers by applying a selective cooperation strategy

Dietary Supplementation with Soluble Plantain Non-Starch Polysaccharides Inhibits Intestinal Invasion of Salmonella Typhimurium in the Chicken

Soluble fibres (non-starch polysaccharides, NSP) from edible plants but particularly plantain banana (Musa spp.), have been shown in vitro and ex vivo to prevent various enteric pathogens from adhering to, or translocating across, the human intestinal epithelium, a property that we have termed contrabiotic. Here we report that dietary plantain fibre prevents invasion of the chicken intestinal mucosa by Salmonella. In vivo experiments were performed with chicks fed from hatch on a pellet diet containing soluble plantain NSP (0 to 200 mg/d) and orally infected with S.Typhimurium 4/74 at 8 d of age. Birds were sacrificed 3, 6 and 10 d post-infection. Bacteria were enumerated from liver, spleen and caecal contents. In vitro studies were performed using chicken caecal crypts and porcine intestinal epithelial cells infected with Salmonella enterica serovars following pre-treatment separately with soluble plantain NSP and acidic or neutral polysaccharide fractions of plantain NSP, each compared with saline vehicle. Bacterial adherence and invasion were assessed by gentamicin protection assay. In vivo dietary supplementation with plantain NSP 50 mg/d reduced invasion by S.Typhimurium, as reflected by viable bacterial counts from splenic tissue, by 98.9% (95% CI, 98.1–99.7; P<0.0001). In vitro studies confirmed that plantain NSP (5–10 mg/ml) inhibited adhesion of S.Typhimurium 4/74 to a porcine epithelial cell-line (73% mean inhibition (95% CI, 64–81); P<0.001) and to primary chick caecal crypts (82% mean inhibition (95% CI, 75–90); P<0.001). Adherence inhibition was shown to be mediated via an effect on the epithelial cells and Ussing chamber experiments with ex-vivo human ileal mucosa showed that this effect was associated with increased short circuit current but no change in electrical resistance. The inhibitory activity of plantain NSP lay mainly within the acidic/pectic (homogalacturonan-rich) component. Supplementation of chick feed with plantain NSP was well tolerated and shows promise as a simple approach for reducing invasive salmonellosis

Complementarity between in-house R&D and technology purchasing: evidence from Chinese manufacturing firms

In order to catch up with the current technological frontier, firms, especially in developing countries, try to acquire technological advancement through internal R&D efforts, as well as through external technology-sourcing activities. This study tests whether these two sources of technology acquisition are complements or substitutes for each other in small- and medium-sized Chinese manufacturing firms. The evidence that we present shows some signs of complementarity between the two sources of knowledge in reaching a higher unconditional intensity of product innovation for firms with 100–300 employees and, in general, a significant degree of substitutability between them in achieving higher levels of labour productivity

Recognition and Degradation of Plant Cell Wall Polysaccharides by Two Human Gut Symbionts

Competition for nutrients contained in diverse types of plant cell wall-associated polysaccharides may explain the evolution of substrate-specific catabolic gene modules in common bacterial members of the human gut microbiota

International patent families: from application strategies to statistical indicators

This paper provides an in-depth analysis of the characteristics of international patent families, including their domestic component. We exploit a relatively under-studied feature of patent families, namely the number of patents covering the same invention within a given jurisdiction. Using this information, we highlight common patterns in the structure of international patent families, which reflect both the patenting strategies of innovators and the peculiarities of the different patent systems. While the literature has extensively used family size, i.e. the number of countries in which a given invention is protected, as a measure of patent value, our results suggest that the number of patent filings in the priority country within a patent family as well as the timespan between the first and last fillings within a family are other insightful indicators of the value of patented innovations