The F-measure for Research Priority Rousseau, Ronald
Journal of data and information science (Warsaw, Poland),
3/2018, Letnik:
3, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract Purpose In this contribution we continue our investigations related to the activity index ( AI ) and its formal analogs. We try to replace the AI by an indicator which is better suited for ...policy applications. Design/methodology/approach We point out that fluctuations in the value of the AI for a given country and domain are never the result of that country’s policy with respect to that domain alone because there are exogenous factors at play. For this reason we introduce the F -measure. This F -measure is nothing but the harmonic mean of the country’s share in the world’s publication output in the given domain and the given domain’s share in the country’s publication output. Findings The F -measure does not suffer from the problems the AI does. Research limitations The indicator is not yet fully tested in real cases. R&D policy management In policy considerations, the AI should better be replaced by the F -measure as this measure can better show the results of science policy measures (which the AI cannot as it depends on exogenous factors). Originality/value We provide an original solution for a problem that is not fully realized by policy makers.
Abstract Purpose New developments in the study of delayed recognition are discussed. Design/methodology/approach Based on these new developments a method is proposed to characterize delayed ...recognition as a fuzzy concept. Findings A benchmark value of 0.333 corresponding with linear growth is obtained. Moreover, a case is discovered in which an expert found delayed recognition several years before citation analysis could discover this phenomenon. Research limitations As all citation studies also this one is database dependent. Practical implications Delayed recognition is turned into a fuzzy concept. Originality/value The article presents a new way of studying delayed recognition.
The scientific foundation for the criticism on the use of the Journal Impact Factor (JIF) in evaluations of individual researchers and their publications was laid between 1989 and 1997 in a series of ...articles by Per O. Seglen. His basic work has since influenced initiatives such as the San Francisco Declaration on Research Assessment (DORA), the Leiden Manifesto for research metrics, and The Metric Tide review on the role of metrics in research assessment and management. Seglen studied the publications of only 16 senior biomedical scientists. We investigate whether Seglen's main findings still hold when using the same methods for a much larger group of Norwegian biomedical scientists with more than 18,000 publications. Our results support and add new insights to Seglen's basic work.
The empirical model developed in the present work allows estimation of crystal size distributions from focused beam reflectance measurements (FBRM) of chord length distributions. The model is ...constructed from purposely varied crystal size distributions and the corresponding measured chord length distributions, which allows construction of a transformation matrix relating the two distributions. Experimental results show advantages over more complex phenomenological models, presumably because the transformation matrix implicitly embodies such phenomena. The ability of the model to address varying crystal concentration and selectively added size fractions is demonstrated with experimental results. Finally, the simplicity of the approach allows rapid (of order 0.1s) estimation of crystal size distributions from FBRM, which is a promising outcome for potentially using the approach in an on-line control scheme.
► A model relates focused beam reflectance measurements to crystal size distribution. ► The model is constructed empirically using known crystal size distributions. ► Experimental results demonstrate the practicality of the method. ► Two inversion methods estimating crystal size distribution are studied and applied.
The kinetics of cephalexin synthesis and hydrolysis of the activated acyl‐donor precursor phenylglycine methyl ester (PGME) were characterized under a broad range of substrate concentrations. A ...previously developed model by Youshko‐Svedas involving the formation of the acyl‐enzyme complex followed by binding of the nucleophilic β‐lactam donor does not fully estimate the maximum reaction yields for cephalexin synthesis at different concentrations using initial‐rate data. 7‐aminodesacetoxycephalosporanic acid (7‐ADCA) was discovered to be a potent inhibitor of cephalexin hydrolysis, which may account for the deviation from model predictions. Three kinetic models were compared for cephalexin synthesis, with the model incorporating competitive inhibition due to 7‐ADCA yielding the best fit. Additionally, the βF24A variant and Assemblase® did not exhibit significantly different kinetics for the synthesis of cephalexin compared to the wild‐type, for the concentration range evaluated and for both initial‐rate experiments and time‐course synthesis experiments. Lastly, a continuous stirred‐tank reactor for cephalexin synthesis was simulated using the model incorporating competitive inhibition by 7‐ADCA, with clear tradeoffs observed between productivity, fractional yield, and PGME conversion.
(Left)—Inhibition of substrate binding by 7‐aminodesacetoxycephalosporanic acid (7‐ADCA). (Right)—Models investigated for the synthesis of cephalexin catalyzed by penicillin G acylase (PGA) with parity plot of best fit model. All models include acyl‐enzyme formation and nucleophilic attack by 7‐ADCA or water. Models 2 and 3 include competitive inhibition by 7‐ADCA or separate binding of 7‐ADCA, respectively.
•Reactive crystallization can be employed to increase the selectivity of ampicillin.•New pH-sensitive model predicts concentrations for non-pH-stat batch reactions.•Experiments confirm model ...predictions of better selectivity towards ampicillin.•Using Assemblase® selectivity is increased 50% by parallel reaction/crystallization.•Yield is improved 20% over the theoretical maximum not considering crystallization.
The enzyme penicillin G acylase (PGA) catalyzes the condensation of phenylglycine methyl ester (PGME) with 6-aminopenicillanic acid (6-APA) to form ampicillin. We improved the selectivity of ampicillin synthesis with PGA by running simultaneous reaction and crystallization. However, the enzyme also catalyzes two undesirable side reactions: the hydrolysis of PGME to phenylglycine and the hydrolysis of ampicillin to phenylglycine and 6-APA. We demonstrate that a fifty percent improvement in selectivity for ampicillin over phenylglycine is achieved by combining reaction and crystallization in batch at pH value of 6 with saturated 6-APA and equimolar PGME. The enhancement in selectivity is mainly attributed to the decreased rates of enzymatic ampicillin hydrolysis; however, the course of the pH value during the reaction also has an effect on enzyme activity that improved selectivity. In addition to showing experimental results, we developed a new kinetic process model that predicts the observed improvement. The new model accounts for the solubility limits of different species as functions of pH value as well as the large change in pH value at high conversion. Previous work does not account for changes in activity with conversion. The pH-dependent activity for the specific enzyme used in this system, Assemblase® from DSM-Sinochem, is well-realized by the model and generalization to other PGAs is possible within the model framework; the selectivity parameters α, β0, and γ for Assemblase® are compared to PGA from E. coli as evidence.
In this opinion paper, we introduce the expressions of
and
in the quantitative studies of science in analogy to the notion of dominant design in product development and innovation.
Social network analysis (SNA) is not a formal theory in sociology but rather a strategy for investigating social structures. As it is an idea that can be applied in many fields, we study, in ...particular, its influence in the information sciences. Information scientists study publication, citation and co-citation networks, collaboration structures and other forms of social interaction networks. Moreover, the Internet represents a social network of an unprecedented scale. In all these studies social network analysis can successfully be applied. SNA is further related to recent theories concerning the free market economy, geography and transport networks. The growth of SNA is documented and a co-author network of SNA is drawn. Centrality measures of the SNA network are calculated.
An Autobiography of Ronald W. Rousseau Rousseau, Ronald W
Annual review of chemical and biomolecular engineering,
06/2018, Letnik:
9, Številka:
1
Journal Article
Recenzirano
Odprti dostop
This article provides a synopsis of my professional career, from the decision to study chemical engineering to leadership of one of the top academic programs in that field. I describe how I chose to ...devote my research to phenomena associated with crystallization as practiced for separation and purification and then made the transition to leader of an academic program. Embedded in the coverage are descriptions of research advances coming from exploration of secondary nucleation, especially how collisions of crystals in supersaturated environments dominate the behavior of industrially relevant crystallization processes. I recount some of the challenges associated with becoming a school chair and how the program I led grew. The story illuminates the contributions of my many mentors, colleagues, and students.
PDF
