Beyond Brigden: Australia’s pre-war manufacturing tariffs, real wages and economic size

Like many industrialised economies in the pre-depression era, Australia elected to maintain a highly protectionist trade policy regime and hence to retard its integration with the global economy. The rationale for Australia’s protectionism was, as elsewhere, the enhancement of worker welfare. The Brigden Report offered a pre-Stolper-Samuelson recognition that protection of labour intensive industries would bolster Australia’s real wage, though the Report did not highlight the further consequence that this would attract European migrants. Brigden’s wage effect mirrors the subsequent Stolper-Samuelson Theorem and Heckscher-Ohlin-Samuelson (HOS) model yet it has still more advanced elements. We illustrate it using the strict two-sector HOS model and a more modern version with differentiated products, three sectors, including a non-traded services sector, natural resources as a specific factor and foreign ownership of domestic capital. While ever production remains diversified, the HOS model with elastic migration does not support a unique link between a single region’s protection and its labour endowment. The more modern model does yield this link, however, suggesting that protection might indeed have fostered, at least temporarily, immigration, capital inflow and overall economic expansion in Australia

A figure of merit for efficiency roll-off in TADF-based organic LEDs

Funding: We are grateful to the Engineering and Physical Sciences Research Council of the UK for financial support through grants EP/R035164/1 and EP/P010482/1.Organic light-emitting diodes (OLEDs) are a revolutionary light-emitting display technology that has been successfully commercialized in mobile phones and TVs1,2. The injected charges form both singlet and triplet excitons, and for high efficiency it is important to enable triplets as well as singlets to emit light. Currently materials that harvest triplets by thermally activated delayed fluorescence (TADF) are a very active field of research as an alternative to phosphorescent emitters which usually employ heavy metal atoms3,4. Whilst excellent progress has been made, there is a severe decrease of efficiency as the drive current is increased, i.e. efficiency roll-off, in most TADF OLEDs. At present much of the literature suggests that efficiency roll-off should be reduced by minimising the energy difference between singlet and triplet excited states (EST) in order to maximise the rate of conversion of triplets to singlets via reverse intersystem crossing (kRISC) 5-20. We analyse the efficiency roll-off in a wide range of TADF OLEDs and find that neither of these parameters fully accounts for the reported efficiency roll-off. By considering the dynamic equilibrium between singlets and triplets in TADF materials, we propose a figure of merit (FOM) for materials design to reduce efficiency roll-off and discuss its correlation with reported data of TADF OLEDs. Our new FOM will guide the design and development of TADF materials that can reduce efficiency roll-off. It will help improve the efficiency of TADF OLEDs at realistic display operating conditions and expand the use of TADF materials to applications that require high brightness, such as lighting, augmented reality, and lasing.Peer reviewe

Cell-to-cell variability in the yeast pheromone response: Cytoplasmic microtubule function stabilizes signal generation and promotes accurate fate choice

In a companion paper, we carried out a high-throughput screen to identify genes that suppressed cell-to-cell variability in signaling in yeast. Two genes affected cytoplasmic microtubules that can connect the nucleus to a signaling site on the membrane. Here, we show that microtubule perturbations that affected polymerization and depolymerization, membrane attachment, and force generation increased variability. For some perturbations, "outlier" cells drove the increased variability. Bypass experiments that activated the PRS ectopically at downstream points indicated that microtubule-dependent processes might stabilize the membrane-recruited scaffold protein Ste5. The variability caused by microtubule perturbations required the MAP kinase Fus3. Microtubule perturbations hindered stable scaffold formation and decreased the accuracy of a polarity-dependent fate choice. Our experiments suggest that membrane-attached microtubules stabilize signaling by scaffold-bound Fus3, and are consistent with a model in which signaling irregularities from changes in microtubule function are amplified by cross-stimulatory feedbacks among PRS proteins. The fact that microtubule perturbations also cause aberrant fate and polarity decisions during embryonic development and cancer initiation suggests that similar variation-reducing processes might also operate in metazoans

Blue-to-green emitting neutral Ir(III) complexes bearing pentafluorosulfanyl groups : a combined experimental and theoretical study

EZ-C acknowledges the University of St Andrews for financial support. The authors are grateful to the EPSRC for financial support from grant EP/M02105X/1, DTG grants: EP/J500549/1, EP/K503162/1, EP/L505097/1. The authors are also grateful to the European Research Council (321305) for support. IDWS is a Royal Society Wolfon Research Merit Award holder.A structure-property relationship study of neutral heteroleptic ( 1 and 2 , [Ir(C^N)2(L^X)]) and homoleptic ( 3 and 4 , fac-[Ir(C^N)3]) Ir(III) complexes [where L^X = anionic 2,2,6,6-tetramethylheptane-3,5-dionato-κO3,κO6 (thd) and C^N = a cyclometalating ligand bearing a pentafluorosulfanyl (-SF5) electron-withdrawing group (EWG) at C4 (H L1 ) and C3 (H L2 ) positions of the phenyl moiety] is presented. These complexes have been fully structurally characterised, including by single crystal X-ray diffraction, and their electrochemical and optical properties have also been extensively studied. While complexes 1 ([Ir( L1 )2(thd)]), 3 (Ir( L1 )3) and 4 (Ir( L2 )3) exhibit irreversible first reduction waves based on the pentafluorosulfanyl substituent in the range of -1.71 V to -1.88 V (vs. SCE), complex 2 ([Ir( L2 )2(thd)]) exhibits a quasi-reversible pyridineC^N-based first reduction wave that is anodically-shifted at -1.38 V. The metal+C^N ligand oxidation waves are all quasi-reversible in the range of 1.08-1.54 V (vs. SCE). The optical gap, determined from the lowest energy absorption maxima, decreases from 4 to 2 to 3 to 1 and this trend is consistent with the Hammett behaviour (σm/σp with respect to the metal-carbon bond) of the –SF5 EWG. In degassed acetonitrile, for complexes 2 - 4 , introduction of the -SF5 group produced a blue-shifted emission (λem = 484-506 nm) compared to reference complexes [Ir(ppy)2(acac)], R1 (where acac = acetylacetonato) (λem = 528 nm in MeCN), [Ir(CF3-ppy)(acac)], R3 (where CF3-ppy = 2-(4-(trifluoromethyl)phenyl)pyridine) (λem = 522 nm in DCM) and [Ir(CF3-ppy)3], R8 (λem = 507 nm in MeCN). The emission of complex 1 , by contrast, was modestly red-shifted (λem = 534 nm). Complexes 2 and 4 , where the –SF5 EWG is substituted para to the Ir-Cppy bond are efficient phosphorescent emitters, with high photoluminescence quantum yields (ΦPL = 58-79% in degassed MeCN solution) and microsecond emission lifetimes (τε = 1.35-3.02 μs). Theoretical and experimental observations point towards excited states that are principally ligand-centered (3LC) in nature, but with a minor metal-to-ligand charge-transfer (3MLCT) transition component, as a function of the regiochemistry of the pentafluorosulfanyl group. The 3LC character is predominant over the mixed 3CT character for complexes 1 , 2 and 4 while in complex 3 , there is exclusive 3LC character as demonstrated by unrestricted Density Functional Theory (DFT) calculations. The short emission lifetimes and reasonable ΦPL values in doped thin film (5 wt% in PMMA), particularly for 4 , suggest that these neutral complexes would be attractive candidate emitters in organic light-emitting diodes.Publisher PDFPeer reviewe

The physical science behind climate change

For a scientist studying climate change, 'eureka' moments are unusually rare. Instead progress is generally made by a painstaking piecing together of evidence from every new temperature measurement, satellite sounding or climate-model experiment. Data get checked and rechecked, ideas tested over and over again. Do the observations fit the predicted changes? Could there be some alternative explanation? Good climate scientists, like all good scientists, want to ensure that the highest standards of proof apply to everything they discover. And the evidence of change has mounted as climate records have grown longer, as our understanding of the climate system has improved and as climate models have become ever more reliable. Over the past 20 years, evidence that humans are affecting the climate has accumulated inexorably, and with it has come ever greater certainty across the scientific community in the reality of recent climate change and the potential for much greater change in the future. This increased certainty is starkly reflected in the latest report of the Intergovernmental Panel on Climate Change (IPCC), the fourth in a series of assessments of the state of knowledge on the topic, written and reviewed by hundreds of scientists worldwide. The panel released a condensed version of the first part of the report, on the physical science basis of climate change, in February. Called the 'Summary for Policymakers,' it delivered to policymakers and ordinary people alike an unambiguous message: scientists are more confident than ever that humans have interfered with the climate and that further human-induced climate change is on the way. Although the report finds that some of these further changes are now inevitable, its analysis also confirms that the future, particularly in the longer term, remains largely in our hands--the magnitude of expected change depends on what humans choose to do about greenhouse gas emissions. The physical science assessment focuses on four topics: drivers of climate change, changes observed in the climate system, understanding cause-and-effect relationships, and projection of future changes. Important advances in research into all these areas have occurred since the IPCC assessment in 2001. In the pages that follow, we lay out the key findings that document the extent of change and that point to the unavoidable conclusion that human activity is driving it

Synthesis, properties and Light-Emitting Electrochemical Cell (LEEC) device fabrication of cationic Ir(III) complexes bearing electron-withdrawing groups on the cyclometallating ligands

The authors are grateful to the European Research Council (grant 321305), the EPSRC (EP/M02105X/1) and the University of St Andrews for financial support. C.M. thanks Ministry of Economy and Competitiveness (MINECO, Spain) for her predoctoral contract.The structure-property relationship study of a series of cationic Ir(III) complexes in the form of [Ir(C^N)2(dtBubpy)]PF6 [where dtBubpy = 4,4′-ditert-butyl-2,2′- bipyridine and C^N = cyclometallating ligand bearing an electron-withdrawing group (EWG) at C4 of the phenyl substituent, i.e. -CF3 ( 1 ), -OCF3 ( 2 ), -SCF3 ( 3 ), -SO2CF3 ( 4 )] have been investigated. The physical and optoelectronic properties of the four complexes were comprehensively characterized, including by X-ray diffraction analysis. All the complexes exhibit quasi-reversible dtBubpy-based reductions from -1.29 V to -1.34 V (vs. SCE). The oxidation processes are likewise quasi-reversible (metal+C^N ligand) and are between 1.54- 1.72 V (vs. SCE). The relative oxidation potentials follow a general trend associated with the Hammett parameter (σ) of the EWGs. Surprisingly, complex 4 bearing the strongest EWG does not adhere to the expected Hammett behavior and was found to exhibit red-shifted absorption and emission maxima. Nevertheless, the concept of introducing EWGs was found to be generally useful in blue-shifting the emission maxima of the complexes (λem = 484-545 nm) compared to that of the prototype complex [Ir(ppy)2(dtBubpy)]PF6 (where ppy = 2- phenylpyridinato) (λem = 591 nm). The complexes were found to be bright emitters in solution at room temperature (ΦPL = 45-66%) with long excited-state lifetimes (τe = 1.14-4.28 μs). The photophysical properties along with Density Functional Theory (DFT) calculations suggest that the emission of these complexes originates from mixed contributions from ligand-centered (LC) transitions and mixed metal-to-ligand and ligand-to-ligand charge transfer (LLCT/MLCT) transitions, depending on the EWG. In complexes 1 , 3 and 4 the 3LC character is prominent over the mixed 3CT character while in complex 2 , the mixed 3CT character is much more pronounced, as demonstrated by DFT calculations and the observed positive solvatochromism effect. Due to the quasi-reversible nature of the oxidation and reduction waves, fabrication of light emitting electrochemical cells (LEECs) using these complexes as emitters was possible with the LEECs showing moderate efficiencies.Publisher PDFPeer reviewe

Ventricular arrhythmias and sudden death in adults after a Mustard operation for transposition of the great arteries

Aims To examine the prevalence of sustained ventricular tachycardia (VT) and sudden death (SD) in adults with atrial repair of transposition of the great arteries (TGA) and to determine associated risk factors. Methods and results In a single-centre review, we studied the outcome of 149 adults (mean age 28 ± 7 years) who had undergone a Mustard operation for TGA. During a mean follow-up of 9 ± 6 years, sustained VT and/or SD occurred in 9% (13/149) of the cohort. Sustained VT/SD was more likely to occur in patients with associated anatomic lesions [hazard ratio (HR) 4.9, 95% CI 1.5-16.0], with NYHA class ≥III (HR 9.8, 95% CI 3.0-31.6) and with an impaired subaortic right ventricular (RV) ejection fraction (EF) (HR 2.2, 95% CI 1.2-4.0 per 10% decrease in EF). There was an inverse correlation between the RV-EF and both age and QRS duration. Patients with a QRS duration ≥140 ms were at highest risk of sustained VT/SD (HR 13.6, 95% CI 2.9-63.4). Atrial tachyarrhythmia was detected in 66 (44%) patients, but was not a statistically significant predictor of sustained VT/SD in our adult population (HR 2.7, 95% CI 0.6-13.0). Conclusion Sustained VT/SD in adults after a Mustard operation for TGA are more common than previously described. Age, systemic ventricular function, and QRS duration are interrelated and are associated with VT/SD. A QRS duration ≥140 ms helps to identify the high risk patien

Multi-responsive thermally activated delayed fluorescence materials : optical ZnCl2 sensors and efficient green to deep-red OLEDs

Funding: China Scholarship Council - 201806890001; Engineering and Physical Sciences Research Council - EP/L017008/1; Horizon 2020 Framework Programme - 101024874; Royal Society - NF171163.Thermally activated delayed fluorescence (TADF) is an emission mechanism whereby both singlet and triplet excitons can be harvested to produce light. Significant attention is devoted to developing TADF materials for organic light-emitting diodes (OLEDs), while their use in other organic electronics applications such as sensors, has lagged. A family of TADF emitters, TPAPyAP, TPAPyBP, and TPAPyBPN containing a triphenylamine (TPA) donor and differing nitrogen-containing heterocyclic pyrazine-based acceptors is developed and systematically studied. Depending on the acceptor strength, these three compounds emit with photoluminescence maxima (λPL), of 516, 550, and 575 nm in toluene. Notably, all three compounds show a strong and selective spectral response to the presence of ZnCl2, making them the first optical TADF sensors for this analyte. It is demonstrated that these three emitters can be used in vacuum-deposited OLEDs, which show moderate efficiencies. Of note, the device with TPAPyBPN in 2,8-bis(diphenyl-phoshporyl)-dibenzo[b,d]thiophene (PPT) host emits at 657 nm and shows a maximum external quantum efficiency (EQEmax) of 12.5%. This electroluminescence is significantly red-shifted yet shows comparable efficiency compared to a device fabricated in 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) host (λEL = 596 nm, EQEmax = 13.6%).Peer reviewe

Tuning the optical properties of silicon quantum dots via surface functionalization with conjugated aromatic fluorophores

The authors acknowledge Karen Nygard at UWO Biotron for assistance with confocal microscopy. This work was financially supported by NSERC Canada Discovery (Charpentier).Silicon Quantum Dots (SQDs) have recently attracted great interest due to their excellent optical properties, low cytotoxicity, and ease of surface modification. The size of SQDs and type of ligand on their surface has a great influence on their optical properties which is still poorly understood. Here we report the synthesis and spectroscopic studies of three families of unreported SQDs functionalized by covalently linking to the aromatic fluorophores, 9-vinylphenanthrene, 1-vinylpyrene, and 3-vinylperylene. The results showed that the prepared functionalized SQDs had a highly-controlled diameter by HR-TEM, ranging from 1.7–2.1 nm. The photophysical measurements of the assemblies provided clear evidence for efficient energy transfer from the fluorophore to the SQD core. Fӧrster energy transfer is the likely mechanism in these assemblies. As a result of the photogenerated energy transfer process, the emission color of the SQD core could be efficiently tuned and its emission quantum efficiency enhanced. To demonstrate the potential application of the synthesized SQDs for bioimaging of cancer cells, the water-soluble perylene- and pyrene-capped SQDs were examined for fluorescent imaging of HeLa cells. The SQDs were shown to be of low cytotoxicity.Publisher PDFPeer reviewe

Solution-processable silicon phthalocyanines in electroluminescent and photovoltaic devices

E.Z.-C. acknowledges the University of St. Andrews for financial support. The authors thank the EPSRC UK National Mass Spectrometry Facility at Swansea University for analytical services. I.D.W.S. acknowledges support from the EPSRC (grant EP/J01771X), the European Research Council (grant 321305), and a Royal Society Wolfson Research Merit Award.Phthalocyanines and their main group and metal complexes are important classes of organic semiconductor materials, but are usually highly insoluble so frequently need to be processed by vacuum deposition in devices. We report two highly soluble silicon phthalocyanine (SiPc) diester compounds and demonstrate their potential as organic semiconductor materials. Near-infrared (λEL = 698-709 nm) solution-processed organic light- emitting diodes (OLEDs) were fabricated and exhibited external quantum efficiencies (EQEs) of up to 1.4%. Binary bulk heterojunction solar cells employing P3HT or PTB7 as the donor and the SiPc as the acceptor provided power conversion efficiencies (PCE) of up to 2.7% under simulated solar illumination. Our results show that soluble SiPcs are promising materials for organic electronics.Publisher PDFPeer reviewe