Flanaganmcintosh8430

Exploration and exploitation are two generic strategies of firms' adaptation to their environments. However, the effectiveness and reliability of these approaches are not fully understood when the business environment is undergoing a major crisis. Building on organizational adaptation, strategic fit, and organizational decline streams of literature, we develop a framework that examines exploration and exploitation in crisis contexts. We argue that the severity of crisis a firm is exposed to acts as a positive contingency for the impact of exploration on firm performance level and variability, and as a negative contingency for exploitation's level and variability effects. Employing the multiplicative heteroscedasticity regression model on the data from 500 Russian SMEs, we test the proposed theoretical framework linking exploration and exploitation activities to the distribution of firm performance under different conditions of the firm-specific crisis severity. The results provide an improved understanding of strategic management approaches under economic crises and related turbulence. © 2020 Elsevier Inc. All rights reserved.A true-false exam can be viewed as being a signal detection task-the task is to detect whether or not an item is true (signal) or false (noise). In terms of signal detection theory (SDT), examinees can be viewed as performing the task by comparing the perceived plausibility of an item (a perceptual component) to a threshold that delineates true from false (a decision component). The resulting model is distinct yet is related to item response theory (IRT) models and grade of membership models, with the difference that SDT explicitly recognizes the role of examinees' perceptions in determining their response to an item. SDT also views IRT concepts such as "difficulty" and "guessing" in a different light, in that both are viewed as reflecting the same aspect-item bias. An application to a true-false algebra exam is presented and the various models are compared. © The Author(s) 2019.Item response theory (IRT) true-score equating for the bifactor model is often conducted by first numerically integrating out specific factors from the item response function and then applying the unidimensional IRT true-score equating method to the marginalized bifactor model. However, an alternative procedure for obtaining the marginalized bifactor model is through projecting the nuisance dimensions of the bifactor model onto the dominant dimension. Projection, which can be viewed as an approximation to numerical integration, has an advantage over numerical integration in providing item parameters for the marginalized bifactor model; therefore, projection could be used with existing equating software packages that require item parameters. In this paper, IRT true-score equating results obtained with projection are compared to those obtained with numerical integration. Simulation results show that the two procedures provide very similar equating results. © The Author(s) 2019.Two-level Mokken scale analysis is a generalization of Mokken scale analysis for multi-rater data. The bias of estimated scalability coefficients for two-level Mokken scale analysis, the bias of their estimated standard errors, and the coverage of the confidence intervals has been investigated, under various testing conditions. It was found that the estimated scalability coefficients were unbiased in all tested conditions. For estimating standard errors, the delta method and the cluster bootstrap were compared. The cluster bootstrap structurally underestimated the standard errors of the scalability coefficients, with low coverage values. Except for unequal numbers of raters across subjects and small sets of items, the delta method standard error estimates had negligible bias and good coverage. Post hoc simulations showed that the cluster bootstrap does not correctly reproduce the sampling distribution of the scalability coefficients, and an adapted procedure was suggested. In addition, the delta method standard errors can be slightly improved if the harmonic mean is used for unequal numbers of raters per subject rather than the arithmetic mean. © The Author(s) 2019.When computerized adaptive testing (CAT) is under stringent item exposure control, the precision of trait estimation will substantially decrease. A new item selection method, the dynamic Stratification method based on Dominance Curves (SDC), which is aimed at improving trait estimation, is proposed to mitigate this problem. The objective function of the SDC in item selection is to maximize the sum of test information for all examinees rather than maximizing item information for individual examinees at a single-item administration, as in conventional CAT. To achieve this objective, the SDC uses dominance curves to stratify an item pool into strata with the number being equal to the test length to precisely and accurately increase the quality of the administered items as the test progresses, reducing the likelihood that a high-discrimination item will be administered to an examinee whose ability is not close to the item difficulty. Furthermore, the SDC incorporates a dynamic process for on-the-fly item-stratum adjustment to optimize the use of quality items. Simulation studies were conducted to investigate the performance of the SDC in CAT under item exposure control at different levels of severity. According to the results, the SDC can efficiently improve trait estimation in CAT through greater precision and more accurate trait estimation than those generated by other methods (e.g., the maximum Fisher information method) in most conditions. © The Author(s) 2019.Limited-information fit measures appear to be promising in assessing the goodness-of-fit of dichotomous response cognitive diagnosis models (CDMs), but their performance has not been examined for polytomous response CDMs. This study investigates the performance of the M ord statistic and standardized root mean square residual (SRMSR) for an ordinal response CDM-the sequential generalized deterministic inputs, noisy "and" gate model. Simulation studies showed that the M ord statistic had well-calibrated Type I error rates, but the correct detection rates were influenced by various factors such as item quality, sample size, and the number of response categories. In addition, the SRMSR was also influenced by many factors and the common practice of comparing the SRMSR against a prespecified cut-off (e.g., .05) may not be appropriate. A set of real data was analyzed as well to illustrate the use of M ord statistic and SRMSR in practice. © The Author(s) 2019.We reexamined the psychometric properties of the Momentary Impulsivity Scale (MIS) in two young adult samples using daily diary (N=77) and ecological momentary assessment (N=147). A one-factor between- and within-person structure was supported, though "I felt impatient" loaded poorly within-person. MIS scores consistently related to emotion-driven trait impulsivity; however, MSSDs of MIS scores were unrelated to outcomes after accounting for aggregate MIS scores. We observed positive, within-person correlations with negative, but not positive, affect. Between-person MIS scores correlated with alcohol problems, though within-person MIS-alcohol relations were inconsistent. MIS scores were unrelated to laboratory-based impulsivity tasks. Findings inform the assessment of state-level impulsivity in young adults. Future research should prioritize expanding the MIS to capture the potential multidimensionality of state-level impulsivity.In this article, we present a highly integrated guidewire ultrasound (US) imaging system-on-a-chip (GUISoC) for vascular imaging. The SoC consists of a 16-channel US transmitter (Tx) and receiver (Rx) electronics, on-chip power management IC (PMIC), and quadrature sampler. Using a synthetic aperture imaging algorithm, a Tx/Rx pair, connected to capacitive micromachined ultrasound transducers (CMUTs), can be activated at any time. The Tx generates acoustic waves by driving the CMUT, while the Rx picks up the echo signal and amplify it to be delivered through an interconnect that is driven by a buffer. On-chip logic controls the pulsers that generate the high-voltage (HV)-pulse for Tx. An on-chip PMIC provides 1.8-, 5-, 39-, and 44-V supplies and a clock signal from the two interconnects besides GND. A quadrature sampler down-converts the Rx echo signal to baseband, reducing its bandwidth requirement for the output interconnect. The system design, including transimpedance amplifier (TIA) optimization, based on the equivalent circuit of a specific CMUT is presented. The SoC was fabricated by a 0.18-μm HV CMOS process, occupying 1.5-mm2 active area and consuming 25.2 and 44 mW from 1.8 to 44 V supplies, respectively. The US Tx and Rx show bandwidths of 32-42 and 32.7-37.5 MHz, respectively. The input-referred noise of the system was measured as 9.66 nA in band with 2-m-long 52 American Wire Gauge (AWG) wire interconnects. The functionality of the GUISoC was verified in vitro by imaging wire targets.Glucocorticoids (GCs) have long played a central role in the treatment of systemic lupus erythematosus (SLE), but these drugs have many adverse effects. We will determine whether rapid weekly GC tapering is non-inferior to conventional biweekly tapering in patients with severe SLE. This is a randomized, open-label, multicenter controlled trial. The primary outcome is the relapse-free survival rate at 52 weeks. The main secondary outcome is the prevalence of the Lupus Low Disease Activity State at 52 weeks. The trial will determine the optimal method of tapering GCs in patients with severe SLE.Urolithiasis, a common condition in patients with spinal deformity, poses a challenge to surgical procedures and anesthetic management. A 51-year-old Chinese male presented with bilateral complex renal calculi. He was also affected by severe kyphosis deformity and spinal stiffness due to ankylosing spondylitis. Dr. Li performed the percutaneous nephrolithotomy under local infiltration anesthesia with the patient in a kneeling prone position, achieving satisfactory stone clearance with no severe complications. We found this protocol safe and effective to manage kidney stones in patients with spinal deformity. Local infiltration anesthesia may benefit patients for whom epidural anesthesia and intubation anesthesia are difficult.A 76-year-old Japanese man was transferred to our hospital to undergo rehabilitation after traffic accident-related injuries. Seven days post-admission, he presented with abdominal pain and an 8-cm lump in the right inguinal region. He was diagnosed with an incarcerated inguinal hernia and underwent elective surgery the day after manual reduction. He had a normal vermiform appendix which was observed to have adhered to the right indirect hernia sac. An appendectomy and hernia repair using lightweight mesh were performed. E-64 We discuss the surgical management of this rare incarcerated Amyand's hernia and the relevant literature.Hereditary hemorrhagic telangiectasia (HHT; also known as Osler-Weber-Rendu disease) is an autosomal dominant genetic disorder that causes frequent epistaxis, mucocutaneous telangiectasia, and visceral arteriovenous malformations. Four genes (ENG, ACVRL1, SMAD4, and GDF2) have been identified as pathogenic in HHT. We describe the case of a 50-year-old Japanese man highly suspected of having HHT due to recurrent epistaxis, mucocutaneous telangiectasia, and a family history. Genomic analysis revealed a novel missense mutation of c.100T>A, p.Cys34Ser in the patient's ACVRL1 gene. We used 6 freeware programs to perform an in silico analysis of this mutation. The results demonstrated the mutation's high pathogenicity.