The Meaningfulness of A Mispriced Option: A Test of the Black-Scholes Model

Ladd M. Kochman is an Associate Professor of Economics and Finance at Nicholls State University, Thibodaux, Louisiana. Uday S. Tate is an Assistant Professor of Business Administration in the School of Business Administration at Iowa State University

Conduction band offset in InAs/GaAs self-organized quantum dots measured by deep level transient spectroscopy

The heterostructure conduction band offset, ΔEc,ΔEc, in InAs/GaAs self-organized quantum dots has been measured by deep level transient spectroscopy. Measurements were made with Au–Al0.18Ga0.82AsAu–Al0.18Ga0.82As Schottky diodes in which the multilayer dots are embedded in the ternary layer. The estimated value of the band offset ΔEc = 341±30 meV.ΔEc=341±30meV. © 2000 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69734/2/APPLAB-76-18-2571-1.pd

Raster-scan imaging with normal-incidence, midinfrared InAs/GaAs quantum dot infrared photodetectors

We demonstrate normal incidence infrared imaging with quantum dot infrared photodetectors using a raster-scan technique. The device heterostructure, containing multiple layers of InAs/GaAs self-organized quantum dots, were grown by molecular-beam epitaxy. Individual devices have been operated at temperatures as high as 150 K and, at 100 K, are characterized by λpeak = 3.72 μm,λpeak=3.72μm, Jdark = 6×10−10 A/cm2Jdark=6×10−10A/cm2 for a bias of 0.1 V, and D∗ = 2.94×109 cm Hz1/2/WD∗=2.94×109cmHz1/2/W at a bias of 0.2 V. Raster-scan images of heated objects and infrared light sources were obtained with a small (13×13)(13×13) interconnected array of detectors (to increase the photocurrent) at 80 K. © 2002 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70691/2/APPLAB-80-18-3265-1.pd

RAPID COMMUNICATION: Lateral hopping conductivity and large negative magnetoresistance in InAs/AlGaAs self-organized quantum dots

We report experimental studies on lateral transport in self-organized quantum dots. We find that below 100 K, conduction occurs through interdot hopping and that experimental results are described quite well by a variable-range hopping model. In the hopping regime, the in-plane conductance varies as G = G0exp [(-T0/T)1/3], and T0 is found to be 7100-9400 K. We have also observed a large negative magnetoresistance in this structure.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48914/2/d215l1.pd

Subclinical left ventricular systolic dysfunction in patients with naive acromegaly — assessment with two-dimensional speckle-tracking echocardiography: retrospective study

Introduction: The aim of the study was to evaluate global longitudinal strain (GLS) in patients with naive acromegaly with normal left ventricular (LV) ejection fraction (EF). Material and methods: Forty-three consecutive patients with naive acromegaly with normal LV systolic function as measured by EF, examined from 2008 to 2016, and 52 patients of a control group matched for age and sex underwent two-dimensional speckle-tracking echocardiography to assess GLS. Results: The median GLS was significantly lower in the acromegaly group than in the control group (in %, –16.6 vs. –20.7; p < 0.01). The majority of acromegalic patients (n = 26; 60.5%) had abnormal GLS. Patients with impairment in GLS had a longer median duration of acromegaly symptoms (in years, 10.0 vs. 5.0; p < 0.05) and greater LV thickness (posterior wall in mm, 12.5 vs. 12.0; p < 0.05) compared to those with normal GLS. Patients with abnormal GLS had higher IGF-1 concentration, but without statistical significance. Diabetes mellitus and arterial hypertension, which are more common in acromegaly, were not significant determinants of abnormal GLS. The mean left ventricular mass index (LVMI) was increased in the acromegaly group compared to controls (in g/m2, 136 vs. 97; p < 0.01). There wasa significant negative correlation between LVMI and GLS (R = –0.47; p < 0.01). Conclusions: Naive acromegalic patients presented abnormal GLS, which indicates subclinical systolic dysfunction in these patients. It has not been proven that arterial hypertension and diabetes mellitus are significant determinants of abnormal GLS

Ring closing reaction in diarylethene captured by femtosecond electron crystallography

The photoinduced ring-closing reaction in diarylethene, which serves as a model system for understanding reactive crossings through conical intersections, was directly observed with atomic resolution using femtosecond electron diffraction. Complementary ab initio calculations were also performed. Immediately following photoexcitation, subpicosecond structural changes associated with the formation of an open-ring excited-state intermediate were resolved. The key motion is the rotation of the thiophene rings, which significantly decreases the distance between the reactive carbon atoms prior to ring closing. Subsequently, on the few picosecond time scale, localized torsional motions of the carbon atoms lead to the formation of the closed-ring photoproduct. These direct observations of the molecular motions driving an organic chemical reaction were only made possible through the development of an ultrabright electron source to capture the atomic motions within the limited number of sampling frames and the low data acquisition rate dictated by the intrinsically poor thermal conductivity and limited photoreversibility of organic materials

Optimal Timing of Coronary Invasive Strategy in Non–ST-Segment Elevation Acute Coronary Syndromes

Background: The optimal timing of coronary intervention in patients with non–ST-segment elevation acute coronary syndromes (NSTE-ACSs) is a matter of debate. Conflicting results among published studies partly relate to different risk profiles of the studied populations. Purpose: To do the most comprehensive meta-analysis of current evidence on early versus delayed invasive treatment in NSTE-ACS. Data Sources: MEDLINE, PubMed Central, and Google Scholar databases; conference proceedings; ClinicalTrials.gov registry; and Current Controlled Trials registry through May 2012. Study Selection: Available randomized, controlled trials (RCTs) and observational studies comparing early versus delayed intervention in the NSTE-ACS population. Data Extraction: Data were extracted for populations, interventions, outcomes, and risk of bias. All-cause mortality was the prespecified primary end point. The longest follow-up available in each study was chosen. The odds ratio with 95% CI was the effect measure. Data Synthesis: Seven RCTs (5370 patients) and 4 observational studies (77 499 patients) were included. Early intervention was less than 20 hours after hospitalization or randomization for RCTs and 24 hours or less for observational studies. Meta-analysis of the RCTs was inconclusive for a survival benefit associated with the early invasive strategy (odds ratio, 0.83 [95% CI, 0.64 to 1.09]; P 0.180); a similar result emerged from the observational studies. With early versus late intervention, the odds ratios in the RCTs were 1.15 (CI, 0.65 to 2.01; P 0.63) and 0.76 (CI, 0.56 to 1.04; P 0.090) for myocardial infarction and major bleeding during follow-up, respectively. Limitation: Current evidence from RCTs is limited by the small overall sample size, low numbers of events in some trials, and heterogeneity in the timing of intervention and in patient risk profiles. Conclusion: At present, there is insufficient evidence either in favor of or against an early invasive approach in the NSTE-ACS population. A more definitive RCT is warranted to guide clinical practice. Primary Funding Source: None