How Do Auditors Behave During Periods of Market Euphoria? The Case of Internet IPOs

The study of periods of market euphoria, such as Holland’s seventeenth-century tulip mania, England’s eighteenth-century South Sea Company, America’s nineteenth-century railroads, or, most recently, the U.S. housing market, is a topic of long-standing interest to economists. Theorists specify conditions under which market participants and institutions cause "bubbles" to arise and persist and empiricists test participant-centric or institution- centric explanations (Hong, Scheinkman, and Xiong 2008; Schultz 2008; Greenwood and Nagel 2009). In this paper, we study a different participant other than one that stands to gain from price fluctuations. We are interested in how auditors behave during periods of market euphoria. Given their gatekeeper responsibility to act in the public’s interest, along with the seeming inevitability of bubbles (Rampell 2009), it is important to study how auditors behave during euphoric market conditions. To address this question, we examine auditor going-concern (GC) opinions around the time of the wave of stressed Internet firms filing to go public on NASDAQ, the capital markets entry point for the companies that went on to constitute "dotcom mania"

Attosecond Time-Domain Measurement of Core-Level-Exciton Decay in Magnesium Oxide.

Excitation of ionic solids with extreme ultraviolet pulses creates localized core-level excitons, which in some cases couple strongly to the lattice. Here, core-level-exciton states of magnesium oxide are studied in the time domain at the Mg L_{2,3} edge with attosecond transient reflectivity spectroscopy. Attosecond pulses trigger the excitation of these short-lived quasiparticles, whose decay is perturbed by time-delayed near-infrared pulses. Combined with a few-state theoretical model, this reveals that the infrared pulse shifts the energy of bright (dipole-allowed) core-level-exciton states as well as induces features arising from dark core-level excitons. We report coherence lifetimes for the two lowest core-level excitons of 2.3±0.2 and 1.6±0.5  fs and show that these are primarily a consequence of strong exciton-phonon coupling, disclosing the drastic influence of structural effects in this ultrafast relaxation process

Dye regeneration and charge recombination in dye-sensitized solar cells with ferrocene derivatives as redox mediators

Ferrocene compounds are promising redox shuttles for application in dye-sensitized solar cells (DSCs). Chemical modification of the cyclopentadienyl rings is easily achievable affording almost unlimited variation of the redox properties. This allows fine-tuning of the driving force for dye-regeneration and optimization of the energy conversion efficiency of DSCs. Herein, six ferrocene derivatives have been chosen for investigation which cover the large redox potential range of 0.85 V, by virtue of simple alkylation and halogenation of the cyclopentadienyl ring, and enable improved matching of the energy levels of the sensitizer and the electrolyte. Although the focus of this work was to examine the effect of the redox potential on charge transfer processes, DSCs were fabricated which achieved high energy conversion efficiencies of over 5%. Charge transfer reactions were studied to reveal the dependence of the dye regeneration rate, recombination losses and recombination pathways on the reaction driving force. An increase in redox potential led to a higher efficiency due to higher open circuit potentials until a threshold is reached. At this threshold, the driving force for dye regeneration (18 kJ DE ¼ 0.19 V) becomes too small for efficient device operation, leading to rapid recombination between the oxidized dye and electrons in the TiO2 conduction band. As a result of this work guidelines can be formulated to aid the selection of redox couples for a particular sensitizer in order to maximize the utilization of incident solar energy

Increased Physical Activity and Reduced Pain with Spinal Cord Stimulation: a 12-Month Study

International Journal of Exercise Science 13(3): 1583-1594, 2020. The purpose of this study was to assess changes in pain and physical activity after replacing a traditional spinal cord stimulation (SCS) implantable pulse generator with a next generation SCS in patients for whom traditional SCS was no longer providing adequate relief of low back and/or leg pain. Subjects (n = 19) who reported that they were no longer receiving adequate relief from traditional SCS were implanted with a next generation SCS. Eighteen additional patients who were receiving relief from traditional SCS were also followed as a control. Both groups (next generation, traditional) were assessed for low-back and limb pain (visual analog scale) and daily physical activity (wearable accelerometer) at baseline and three, six, nine and 12 months following the SCS implant. Relative to baseline, next generation SCS subjects exhibited reductions (p ≤ 0.05 for all) in low-back pain (average reduction of 22%) at every time point, in leg pain (average reduction of 23%) at every time point except six months and increased physical activity (average increase of 57%) at three, six and nine months. As expected, there were no changes in pain or physical activity in the traditional SCS subjects (p ≥ 0.1). In conclusion, pain decreased, and physical activity increased in patients receiving a next generation SCS. Physical activity may serve as an objectively measured marker of pain

Trials and tribulations of designing multitasking catalysts for olefin/thiophene block copolymerizations

Block copolymers containing both insulating and conducting segments have been shown to exhibit improved charge transport properties and air stability. Nevertheless, their syntheses are challenging, relying on multiple post‐polymerization functionalization reactions and purifications. A simpler approach would be to synthesize the block copolymer in one pot using the same catalyst to enchain both monomers via distinct mechanisms. Such multitasking polymerization catalysts are rare, however, due to the challenges of finding a single catalyst that can mediate living, chain‐growth polymerizations for each monomer under similar conditions. Herein, a diimine‐ligated Ni catalyst is evaluated and optimized to produce block copolymer containing both 1‐pentene and 3‐hexylthiophene. The reaction mixture also contains both homopolymers, suggesting catalyst dissociation during and/or after the switch in mechanisms. Experimental and theoretical studies reveal a high energy switching step coupled with infrequent catalyst dissociation as the culprits for the low yield of copolymer. Combined, these studies highlight the challenges of identifying multitasking catalysts, and suggest that further tuning the reaction conditions (e.g., ancillary ligand structure and/or metal) is warranted for this specific copolymerization. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 132–137Block copolymers containing insulating segments (derived from 1‐pentene) and conducting segments (derived from 3‐hexylthiophene) are synthesized in one pot using a single multitasking catalyst. Notably, this process requires different enchainment mechanisms (coordination/insertion vs. cross‐coupling) mediated by the same precatalyst. Nevertheless, the block copolymer is the minor product due to a slow switching step between the mechanisms coupled with catalyst dissociation from the polymer chain.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139919/1/pola28885_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139919/2/pola28885.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139919/3/pola28885-sup-0001-suppinfo.pd

Service use and costs for people with headache: a UK primary care study

This paper aims to estimate the service and social costs of headache presenting in primary care and to identify predictors of headache costs. Patients were recruited from GP practices in England and service use and lost employment recorded. Predictors of cost were identified using regression models. Service and social costs were available on 288 and 282 patients, respectively. Average service costs over 3 months were £117 whilst total costs (including lost production) were £582. Patients referred to neurologists had service costs that were £82 higher than those not referred (90% CI £36–£128). Costs including lost employment were higher by £150, but this was not significant (90% CI -£139–£439). The annual mean service and social costs, weighted to represent population rates of referral, were £468 and £2328, respectively. Higher costs were significantly related to pain. Age was linked to higher service costs and lower social costs. The figures extrapolated to the whole of the UK suggest £956 million due to service use and £4.8 billion including lost employment. These are likely to be underestimates because many people experiencing headaches do not consult their GP

Myocardial production and release of MCP-1 and SDF-1 following myocardial infarction: differences between mice and man

<p>Abstract</p> <p>Background</p> <p>Stem cell homing to the heart is mediated by the release of chemo-attractant cytokines. Stromal derived factor -1 alpha (SDF-1a) and monocyte chemotactic factor 1(MCP-1) are detectable in peripheral blood after myocardial infarction (MI). It remains unknown if they are produced by, and released from, the heart in order to attract stem cells to repair the damaged myocardium.</p> <p>Methods</p> <p>Murine hearts were studied for expression of MCP-1 and SDF-1a at day 3 and day 28 following myocardial infarction to determine whether production is increased following MI. In addition, we studied the coronary artery and coronary sinus (venous) blood from patients with normal coronary arteries, stable coronary artery disease (CAD), unstable angina and MI to determine whether these cytokines are released from the heart into the systemic circulation following MI.</p> <p>Results</p> <p>Both MCP-1 and SDF-1a are constitutively produced and released by the heart. MCP-1 mRNA is upregulated following murine experimental MI, but SDF-1a is suppressed. There is less release of SDF-1a into the systemic circulation in patients with all stages of CAD including MI, mimicking the animal model. However MCP-1 release from the human heart following MI is also suppressed, which is the exact opposite of the animal model.</p> <p>Conclusions</p> <p>SDF-1a and MCP-1 release from the human heart are suppressed following MI. In the case of SDF-1a, the animal model appropriately reflects the human situation. However, for MCP-1 the animal model is the exact opposite of the human condition. Human observational studies like this one are paramount in guiding translation from experimental studies to clinical trials.</p