5,165 research outputs found

    Continuous-flow reactors for the rapid evolution and validation of kinetic motifs

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    In this paper we apply the concept of a kinetic motif as a simple way to represent all the time-dependent behaviour in a single-step or multi-step reaction system. Small-scale continuous-flow reactors offer the potential to rapidly collect large amounts of data while accessing conventionally challenging experimental conditions. The scope of the approach is demonstrated on reaction case study examples

    The Effects of Communication on the Partnership Solution to the Commons

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    © 2017, Springer Science+Business Media Dordrecht. Organizing individual appropriators into output sharing groups has been found to effectively solve the tragedy of the commons problem. We experimentally investigate the robustness of this solution by introducing different channels of communication that naturally arise from group competitions. In the absence of communication, we confirm that output sharing can introduce sufficient free riding to offset over-harvesting and results in full efficiency. Allowing local communication within output-sharing groups substantially decreases this efficiency enhancement because it reduces free riding and boosts between-group competition. Yet the efficiency level is still significantly higher than that achieved when global communication is allowed among all appropriators in a conventional common pool resource without output sharing. The efficiency-reducing effect of local communication is mitigated when random partners instead of fixed partners are sharing output over time, and is nearly eliminated when random partners are formed with users who belong to different communication groups

    Appropriation from a common pool resource: effects of the characteristics of the common pool resource, the appropriators and the existence of communication

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    © 2017 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. There is a growing literature that studies the management of Common Pool Resources (CPRs) within the context of controlled laboratory experiments. A major thesis of this work is that non-binding communication (cheap talk) among appropriators of the commons may be sufficient to permit them to manage the commons efficiently without requiring an outside regulator. In this chapter we compare three CPR environments in controlled laboratory sessions with and without non-binding communication. We identify the nature of the differences across the environments and propose several new environments that may support a conjecture that cognitive differences induced by the framing of the sessions leads to the differences we find. Our results suggest that the success of nonbinding communication in reducing over-appropriation from a CPR may be dependent upon the characteristics of the CPR's yield function, the nature of the communication and the number of appropriators

    Why Some Interfaces Cannot be Sharp

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    A central goal of modern materials physics and nanoscience is control of materials and their interfaces to atomic dimensions. For interfaces between polar and non-polar layers, this goal is thwarted by a polar catastrophe that forces an interfacial reconstruction. In traditional semiconductors this reconstruction is achieved by an atomic disordering and stoichiometry change at the interface, but in multivalent oxides a new option is available: if the electrons can move, the atoms don`t have to. Using atomic-scale electron energy loss spectroscopy we find that there is a fundamental asymmetry between ionically and electronically compensated interfaces, both in interfacial sharpness and carrier density. This suggests a general strategy to design sharp interfaces, remove interfacial screening charges, control the band offset, and hence dramatically improving the performance of oxide devices.Comment: 12 pages of text, 6 figure

    The present rate of Supernovae

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    We present and discuss the most recent determination of the rate of Supernovae in the local Universe. A comparison with other results shows a general agreement on the gross values but still significant differences on the values of the rates of various SN rates in different kinds of galaxies. The rate of SNe, used as a probe of Star Formation, confirms the young progenitor scenario for SNII+Ib/c. The increasing diversity of SNe reflects also in the SN yields which may affect the chemical evolution of the Galaxy but, because of the limited statistics, we cannot estimate the contributions of the new subtypes yet. It is also expected that in a few years observational determinations of the SN rates at various look-back times will be available.Comment: 9 pages, Latex, 1 figure, To appear in the proceedings of the conference "The Chemical Evolution of The Milky Way: Stars versus Clusters", eds. F. Matteucci and F. Giovannelli, Vulcano, Italy, September 20-24 199

    Considering the Case for Biodiversity Cycles: Reexamining the Evidence for Periodicity in the Fossil Record

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    Medvedev and Melott (2007) have suggested that periodicity in fossil biodiversity may be induced by cosmic rays which vary as the Solar System oscillates normal to the galactic disk. We re-examine the evidence for a 62 million year (Myr) periodicity in biodiversity throughout the Phanerozoic history of animal life reported by Rohde & Mueller (2005), as well as related questions of periodicity in origination and extinction. We find that the signal is robust against variations in methods of analysis, and is based on fluctuations in the Paleozoic and a substantial part of the Mesozoic. Examination of origination and extinction is somewhat ambiguous, with results depending upon procedure. Origination and extinction intensity as defined by RM may be affected by an artifact at 27 Myr in the duration of stratigraphic intervals. Nevertheless, when a procedure free of this artifact is implemented, the 27 Myr periodicity appears in origination, suggesting that the artifact may ultimately be based on a signal in the data. A 62 Myr feature appears in extinction, when this same procedure is used. We conclude that evidence for a periodicity at 62 Myr is robust, and evidence for periodicity at approximately 27 Myr is also present, albeit more ambiguous.Comment: Minor modifications to reflect final published versio

    Process Monitoring of Moisture Content and Mass Transfer Rate in a Fluidised Bed with a Low Cost Inline MEMS NIR Sensor

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    Purpose The current trend for continuous drug product manufacturing requires new, affordable process analytical techniques (PAT) to ensure control of processing. This work evaluates whether property models based on spectral data from recent Fabry–Pérot Interferometer based NIR sensors can generate a high-resolution moisture signal suitable for process control. Methods Spectral data and offline moisture content were recorded for 14 fluid bed dryer batches of pharmaceutical granules. A PLS moisture model was constructed resulting in a high resolution moisture signal, used to demonstrate (i) endpoint determination and (ii) evaluation of mass transfer performance. Results The sensors appear robust with respect to vibration and ambient temperature changes, and the accuracy of water content predictions (±13 % ) is similar to those reported for high specification NIR sensors. Fusion of temperature and moisture content signal allowed monitoring of water transport rates in the fluidised bed and highlighted the importance water transport within the solid phase at low moisture levels. The NIR data was also successfully used with PCA-based MSPC models for endpoint detection. Conclusions The spectral quality of the small form factor NIR sensor and its robustness is clearly sufficient for the construction and application of PLS models as well as PCA-based MSPC moisture models. The resulting high resolution moisture content signal was successfully used for endpoint detection and monitoring the mass transfer rate

    Gout severity, socioeconomic status and work absence: a cross-sectional study in primary care

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    Objective To examine the association between gout severity and socioeconomic status (SES) and gout severity and work absence. Methods Postal questionnaires were sent to adult patients who were registered with 20 general practices and who had consultations regarding gout or had been prescribed allopurinol or colchicine in the preceding 2 years. Gout severity was defined using the following proxy measures: number of attacks, history of oligoarticular/polyarticular attacks, disease duration, and allopurinol use. SES was defined using the English index of multiple deprivation (area level) and using self-reported educational attainment (individual level). Work absence was defined as taking time off from work in the past 6 months because of gout. Adjusted odds ratios (ORadj; 95% confidence intervals [95% CIs]) were calculated using logistic regression models (adjusted for age, sex, body mass index, gout severity, and comorbidities). Results A total of 1,184 completed questionnaires were returned. The mean age of patients was 65.6 years, and 84% were male. Not having attended further education ("further education" is defined as attendance after the statutory minimum school-leaving age of 16 years) was associated with having had >= 2 gout attacks in the last year (ORadj 0.54 [95% CI 0.36-0.81]) and oligoarticular/polyarticular attacks (ORadj 0.72 [95% CI 0.50-1.05]). Lower area-level deprivation was associated with fewer attacks (>= 2) (ORadj 0.71 [95% CI 0.51-0.98]). Work absence was associated with having had >= 2 gout attacks in the last year (ORadj 2.91 [95% CI 1.22- 6.92]), oligoarticular/polyarticular attacks (ORadj 3.10 [95% CI 1.46-6.61]), and shorter disease duration (>18 years) (ORadj 0.13 [95% CI 0.03-0.50]). Conclusion Gout severity was associated with individual-level deprivation, countering the historic and negative perception of gout as a "rich man's disease." The association of gout severity with work absence reinforces the argument for earlier urate-lowering therapy to prevent attacks from becoming frequent and debilitating

    [ 11 C]NNC 12-0722 or [ 18 F]GBR 13119: Just what is “better”?

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46836/1/259_2004_Article_BF00285593.pd
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