Structure analysis of single- and multi-frequency subspace migrations in inverse scattering problems

In this literature, we carefully investigate the structure of single- and multi-frequency imaging functions, that are usually employed in inverse scattering problems. Based on patterns of the singular vectors of the Multi-Static Response (MSR) matrix, we establish a relationship between imaging functions and the Bessel function. This relationship indicates certain properties of imaging functions and the reason behind enhancement in the imaging performance by multiple frequencies. Several numerical simulations with a large amount of noisy data are performed in order to support our investigation.Comment: 11 pages, 10 figure

Strategic Alliances And New Product Development In High-Tech Ventures: The Moderating Role Of Alliance Type And Alliance Capability

Strategy scholars have proposed that capacity for managing alliance can be a source of superior performance. This study focuses on the role of this capacity, and investigates how alliance management capability of entrepreneurial firms affects the relationship between a firm’s allying and its performance. Because the capability is inherently unobservable, we take alliance experience and average duration of each alliance as proxy variables for measuring alliance management capability. An analysis of multiple allies of entrepreneurial ventures in Korean photovoltaic industry indicate that capacity for managing varying allies, and alliance type positively moderate the relation between alliance and its innovation outcomes

Test Equating of the Medical Licensing Examination in 2003 and 2004 Based on the Item Response Theory

The passing rate of the Medical Licensing Examination has been variable, which probably originated from the difference in the difficulty of items and/or difference in the ability level of examinees. We tried to explain the origin of the difference using the test equating method based on the item response theory. The number of items and examinees were 500, 3,647 in 2003 and 550, 3,879 in 2004. Common item nonequivalent group design was used for 30 common items. Item and ability parameters were calculated by three parametric logistic models using ICL. Scale transformation and true score equating were executed using ST and PIE. The mean of difficulty index of the year 2003 was -0.957 (SD 2.628) and that of 2004 after equating was -1.456 (SD 3.399). The mean of discrimination index of year 2003 was 0.487 (SD 0.242) and that of 2004 was 0.363 (SD 0.193). The mean of ability parameter of year 2003 was 0.00617 (SD 0.96605) and that of year 2004 was 0.94636 (SD 1.32960). The difference of the equated true score at the same ability level was high at the range of score of 200-350. The reason for the difference in passing rates over two consecutive years was due to the fact that the Examination in 2004 was easier and the abilities of the examinees in 2004 were higher. In addition, the passing rates of examinees with score of 270-294 in 2003, and those with 322-343 in 2004, were affected by the examination year

The relationship of examinees’ individual characteristics and perceived acceptability of smart device-based testing to test scores on the practice test of the Korea Emergency Medicine Technician Licensing Examination

Purpose Smart device-based testing (SBT) is being introduced into the Republic of Korea’s high-stakes examination system, starting with the Korean Emergency Medicine Technician Licensing Examination (KEMTLE) in December 2017. In order to minimize the effects of variation in examinees’ environment on test scores, this study aimed to identify any associations of variables related to examinees’ individual characteristics and their perceived acceptability of SBT with their SBT practice test scores. Methods Of the 569 candidate students who took the KEMTLE on September 12, 2015, 560 responded to a survey questionnaire on the acceptability of SBT after the examination. The questionnaire addressed 8 individual characteristics and contained 2 satisfaction, 9 convenience, and 9 preference items. A comparative analysis according to individual variables was performed. Furthermore, a generalized linear model (GLM) analysis was conducted to identify the effects of individual characteristics and perceived acceptability of SBT on test scores. Results Among those who preferred SBT over paper-and-pencil testing, test scores were higher for male participants (mean± standard deviation [SD], 4.36± 0.72) than for female participants (mean± SD, 4.21± 0.73). According to the GLM, no variables evaluated— including gender and experience with computer-based testing, SBT, or using a tablet PC—showed a statistically significant relationship with the total score, scores on multimedia items, or scores on text items. Conclusion Individual characteristics and perceived acceptability of SBT did not affect the SBT practice test scores of emergency medicine technician students in Korea. It should be possible to adopt SBT for the KEMTLE without interference from the variables examined in this study

Comparative proteomic analysis of early salt stress-responsive proteins in roots of SnRK2 transgenic rice

<p>Abstract</p> <p>Background</p> <p>The rice roots are highly salt-sensitive organ and primary root growth is rapidly suppressed by salt stress. Sucrose nonfermenting 1-related protein kinase2 (SnRK2) family is one of the key regulator of hyper-osmotic stress signalling in various plant cells. To understand early salt response of rice roots and identify SnRK2 signaling components, proteome changes of transgenic rice roots over-expressing OSRK1, a rice SnRK2 kinase were investigated.</p> <p>Results</p> <p>Proteomes were analyzed by two-dimensional electrophoresis and protein spots were identified by LC-MS/MS from wild type and OSRK1 transgenic rice roots exposed to 150 mM NaCl for either 3 h or 7 h. Fifty two early salt -responsive protein spots were identified from wild type rice roots. The major up-regulated proteins were enzymes related to energy regulation, amino acid metabolism, methylglyoxal detoxification, redox regulation and protein turnover. It is noted that enzymes known to be involved in GA-induced root growth such as fructose bisphosphate aldolase and methylmalonate semialdehyde dehydrogenase were clearly down-regulated. In contrast to wild type rice roots, only a few proteins were changed by salt stress in OSRK1 transgenic rice roots. A comparative quantitative analysis of the proteome level indicated that forty three early salt-responsive proteins were magnified in transgenic rice roots at unstressed condition. These proteins contain single or multiple potential SnRK2 recognition motives. In vitro kinase assay revealed that one of the identified proteome, calreticulin is a good substrate of OSRK1.</p> <p>Conclusions</p> <p>Our present data implicate that rice roots rapidly changed broad spectrum of energy metabolism upon challenging salt stress, and suppression of GA signaling by salt stress may be responsible for the rapid arrest of root growth and development. The broad spectrum of functional categories of proteins affected by over-expression of OSRK1 indicates that OSRK1 is an upstream regulator of stress signaling in rice roots. Enzymes involved in glycolysis, branched amino acid catabolism, dnaK-type molecular chaperone, calcium binding protein, Sal T and glyoxalase are potential targets of OSRK1 in rice roots under salt stress that need to be further investigated.</p

The Effect of Clonidine Pretreatment on Epidural Resiniferatoxin in a Neuropathic Pain Rat Model

Resiniferatoxin (RTX) is an ultrapotent synthetic TRPV1 (transient receptor potential vanilloid subtype 1) agonist with significant initial transient hyperalgesia followed by a prolonged analgesic effect in response to thermal stimulus. Using a rat model of neuropathic pain, we evaluated the effect of pretreatment with clonidine－which has been shown to relieve intradermal capsaicin-induced hyperalgesia－on the initial hyperalgesic response and the thermal analgesic property of RTX. Thirty-six male rats were divided into 6 treatment groups (n＝6 each):RTX 500ng, RTX 1μg, clonidine 20μg (Cl), Cl＋RTX 500ng, Cl＋RTX 1μg, or normal saline 20μL (control). We evaluated the short-term (180min) and long-term (20 days) analgesic effects of RTX after thermal stimulation and mechanical stimulation. RTX had significant initial transient hyperalgesia followed by a prolonged analgesic effect in response to the thermal stimulus, but the RTX 500ng and RTX 1μg groups showed no initial short-term thermal hyperalgesic responses when pretreated with clonidine. The Cl＋RTX 1μg ratsʼ behavior scores indicated that they were more calm and comfortable compared to the RTX 1μg rats. Even though we cannot precisely confirm that pretreatment with clonidine potentiates or adds to the analgesic effect of RTX, clonidine pretreatment with epidural RTX eliminated the initial RTX-associated hyperalgesic response and systemic toxicity in this neuropathic pain rat model

A fatal case of acute pulmonary embolism caused by right ventricular masses of acute lymphoblastic lymphoma-leukemia in a 13 year old girl

We report a case of a 13-year-old girl with acute lymphoblastic lymphoma-leukemia, who presented with a cardiac metastasis in the right ventricle, resulting in a pulmonary embolism. At the time of her leukemia diagnosis, a cardiac mass was incidentally found. The differential diagnosis for this unusual cardiac mass included cardiac tumor, metastasis, vegetation, and thrombus. Empirical treatment was initiated, including anticoagulation and antibiotics. She underwent plasmapheresis and was administered oral prednisolone for her leukemia. Five days later, she experienced sudden hemodynamic collapse and required extracorporeal membrane oxygenation insertion and emergency surgery. These interventions proved futile, and the patient died. Pathology revealed that the cardiac mass comprised an aggregation of small, round, necrotic cells consistent with leukemia. This is the first known case of acute lymphoblastic leukemia presenting as a right ventricular mass, with consequent fatal acute pulmonary embolism. A cardiac mass in a child with acute leukemia merits investigation to rule out every possible etiology, including vegetation, thrombus, and even a mass of leukemic cells, which could result in the fatal complication of pulmonary embolism