Method for Identifying Actors in a Knowledge Based Cluster

The objective of the paper is to develop a method through which we can identify the actors (industrial, institutional and individual) who are active in technology development in the same or similar knowledge fields. The paper is, thus, aimed to make a methodological contribution to the literature, which has emerged on the systemic nature of innovation. The method involves broadening out from a starting point in a specific patent class, which corresponds as closely as possibly to the technological area of interest, to a set of related patent classes by using co-classifications and citations. After close scrutiny of both patent classes and patents, the actors in the new classes, as well as in the original class, are then identified. We try out the method on radio wave antennas for communication technology in Sweden. We find a range of firms and other actors in a whole set of industries, which bear little relation to one another in an input-output sense. Although we can not ascertain the extent of linkages or relations between these actors, our hypothesis is that they constitute a cluster around radio wave antenna technology in Sweden.knowledge-based clusters, indicators, patents, similar and complementary technologies, horisontal linkages, knowledge spillovers, actors

Polycyclic aromatic hydrocarbon sorption kinetics in three iron oxide-coated aquifer sands

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1995.Includes bibliographical references.by Britt A. Holmén.Ph.D

Mechanisms of goethite dissolution in the presence of desferrioxamine B and Suwannee River fulvic acid at pH 6.5

Siderophores are Fe3+ specific low MW chelating ligands secreted by microorganisms in response to Fe stress. Low MW organic acids such as oxalate have been shown to enhance siderophore mediated dissolution of Fe3+ oxides. However, the effect of fulvic acid presence on siderophore function remains unknown. We used batch dissolution experiments to investigate Fe release from goethite in the goethite-fulvic acid desferrioxamine B (goethite-SRFA-DFOB) ternary system. Experiments were conducted at pH 6.5 while varying reagent addition sequence. FTIR and UV-Vis spectroscopy were employed to characterise the Fe-DFOB, Fe-SRFA and DFOB–SRFA complexes. Iron released from goethite in the presence of SRFA alone was below detection limit. In the presence of both SRFA and DFOB, dissolved Fe increased with reaction time, presence of the DFOB-SRFA complex, and where SRFA was introduced prior to DFOB. FTIR data show that in the ternary system, Fe3+ is complexed primarily to oxygen of the DFOB hydroxamate group, whilst the carboxylate C=O of SRFA forms an electrostatic association with the terminal NH3+ of DFOB. We propose that SRFA sorbed to goethite lowers the net positive charge of the oxide surface, thus facilitating adsorption of cationic DFOB and subsequent Fe3+ chelation and release. Furthermore, the sorbed SRFA weakens Fe-O bonds at the goethite surface, increasing the population of kinetically labile Fe. This work demonstrates the positive, though indirect role of SRFA in increasing the bioavailability of Fe3+

Environmental Traffic Assignment: Developing Emission-based Models

ABSTRACT Vehicle tailpipe emissions are major sources of air pollution and greenhouse gases. In addition to the ongoing efforts on emissions reduction, we believe there is a need to explore an innovating approach in which drivers routing decisions are influenced to minimize emissions and fuel consumption. In order to evaluate such transportation systems, we develop environmental traffic assignment models (E-TA) based on user equilibrium (UE) and system optimal (SO) behavioral principles. Extending the traditional travel time based UE and SO principles to E-TA is not straightforward because, unlike travel time, vehicle emissions increase with the increase in vehicle speed beyond a certain point. The results of various TA models show a network-wide traffic control strategy in which vehicles are routed according to SO based E-TA, can reduce system wide emissions. However, a system in which drivers make routing decisions to minimize their own emissions, (E-UE system) results in increased individual as well as systemwide emissions. KEY WORDS: Traffic Assignment, vehicle emissions, link cost function 3 Patil, Aultman-Hall, and Holme

Tobacco use and caries risk among adolescents - a longitudinal study in Sweden

Background: Smoking and the use of smokeless tobacco have a detrimental impact on general and oral health. The relationship to dental caries is however still unclear. As caries is a multi-factorial disease with clear life-style, socio-economic and socio-demographic gradients, the tobacco use may be a co-variable in this complex rather than a direct etiological factor. Our aim was to analyze the impact of tobacco use on caries incidence among adolescents, with consideration to socio-economic variables by residency, using epidemiological data from a longitudinal study in the region of Halland, Sweden. Methods: The study population consisted of 10,068 adolescents between 16-19 years of age from whom yearly data on caries and tobacco use (cigarette smoking and use of smokeless tobacco) were obtained during the period 2006-2012. Reported DMFS increment between 16 and 19 years of age (Delta DMFS) for an individual was considered as the primary caries outcome. The outcome data were compared for self-reported never vs. ever users of tobacco, with consideration to neighborhood-level socio-economy (4 strata), baseline (i.e., 16 years of age) DMFS and sex. The region consists of 65 parishes with various socio-economic conditions and each study individual was geo-coded with respect to his/her residence parish. Neighborhood (parish-level) socio-economy was assessed by proportion of residing families with low household purchasing power. Results:Delta DMFS differed evidently between ever and never users of tobacco (mean values: 1.8 vs. 1.2; proportion with Delta DMFS > 0: 54.2% vs. 40.5%; p < 0.0001). Significant differences were observed in each neighborhood-level socio-economic stratum. Even after controlling for baseline DMFS and sex, Delta DMFS differed highly significantly between the ever and never users of tobacco (overall p < 0.0001). Conclusion: Tobacco use was clearly associated with increased caries increment during adolescence. Hence, this factor is relevant to consider in the clinical caries risk assessment of the individual patient as well as for community health plans dealing with oral health

Rapid fucosylation of intestinal epithelium sustains host–commensal symbiosis in sickness

Systemic infection induces conserved physiological responses that include both resistance and ‘tolerance of infection’ mechanisms. Temporary anorexia associated with an infection is often beneficial, reallocating energy from food foraging towards resistance to infection or depriving pathogens of nutrients. However, it imposes a stress on intestinal commensals, as they also experience reduced substrate availability; this affects host fitness owing to the loss of caloric intake and colonization resistance (protection from additional infections). We hypothesized that the host might utilize internal resources to support the gut microbiota during the acute phase of the disease. Here we show that systemic exposure to Toll-like receptor (TLR) ligands causes rapid α(1,2)-fucosylation of small intestine epithelial cells (IECs) in mice, which requires the sensing of TLR agonists, as well as the production of interleukin (IL)-23 by dendritic cells, activation of innate lymphoid cells and expression of fucosyltransferase 2 (Fut2) by IL-22-stimulated IECs. Fucosylated proteins are shed into the lumen and fucose is liberated and metabolized by the gut microbiota, as shown by reporter bacteria and community-wide analysis of microbial gene expression. Fucose affects the expression of microbial metabolic pathways and reduces the expression of bacterial virulence genes. It also improves host tolerance of the mild pathogen Citrobacter rodentium. Thus, rapid IEC fucosylation appears to be a protective mechanism that utilizes the host’s resources to maintain host–microbial interactions during pathogen-induced stress

Instantaneous Hybridization Factor (IHF) Development for HEV Energy-Emissions Analyses Using Real-World, On-Board Data

Past research has shown on-road emissions patterns unique to HEVs, indicating the need to account for them in emissions models. The main objective of this work is to outline a framework for development of new HEV emissions models based on current knowledge of CV emissions. The premise is that accurate knowledge of the instantaneous (1 Hz) power split between the HEV combustion and electric propulsion sources can be used to modify existing CV emission models for HEV emission predictions that are currently lacking in regulatory models. The HEV power split metric, instantaneous hybridization factor (IHF), was developed and quantified with on-road data collected from a 2010 Toyota Camry HEV operating on a fixed route in hilly Vermont over all seasons. IHF is the second-by-second ratio of electric system power to total system power and accounts for energy storage in the high voltage battery. IHF ranges from -1 to +1 and varies widely with vehicle speed and VSP. Different road types on the driving route were associated with different proportions of binned IHF activity, which represent the three key HEV operating states defined in this study: electric-drive only (EDO), power recovery and electric-drive assist. A more detailed analysis of IHF relationships to tailpipe emissions and road grade is found in a recently published article (Ref 1).View the NCST Project Webpag