• 한국수학사학회지
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• 제20권3호
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• pp.59-72
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• 2007

복소수 발견초기 수학자들은 복소수에 대한 거부감이 상당했으나 복소수의 대수적 연산에는 큰 어려움이 없었다. 복소수가 수학적 대상으로 인정받기까지 많은 시간이 필요했던 이유는 복소수의 기하적 해석에 많은 시행착오와 시간이 필요했기 때문이다. 본 논문은 복소수의 기하적 해석의 싹을 Euclid 원론에서 찾고, Descarte, Wallis, Wessel를 거치면서 그 싹이 틔어가는 과정을 밝히고 있다. 복소수의 기하적 해석에 대한 세 명의 수학자들의 생각은 서로 다르지만 밀접한 관계가 있다. 이들은 선분과 복소수의 관계에 주목하고, 곱셈 연산을 일반화하면서 복소수의 기하적 해석을 시도하였다.

• 수산해양기술연구
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• 제47권4호
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• pp.419-427
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• 2011

Simulation technique for the fish behavior was applied to estimate fish school movement in the cage net. Individual-based fish behavior model (Huth and Wessel, 1991) was evaluated in a free area to understand the characteristics for the model, and the movement in the cage net was simulated by defining the fish reaction against the displacement of cage net. As a result, the distance to the net was not considerably changed and the space among fishes in cage net was slightly decreased by reducing the net space. Swimming area was, however, significantly affected by changing the net space and the relationship between swimming area and net displacement was theoretically estimated as y=-0.21x+1.02 ($R^2$=0.96). these results leads the conclusion that individual-based model was appropriated to describe the fish school reaction in the cage net and be able to use for evaluating the influence on cultured fish.

• Clinics in Shoulder and Elbow
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• 제25권1호
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• pp.57-64
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• 2022

Background: There are various conservative treatment options for lateral epicondylitis (LE). The aim is to evaluate pain, daily functioning, and complications after ultrasound-standardized autologous blood injections in patients with LE. Methods: For this prospective cohort study, consecutive patients (>18 years) diagnosed with LE were included. Autologous blood was injected using a medical device containing an injection disposable with 12 small needles (Instant Tennis Elbow Cure [ITEC]) device. Patient-Rated Tennis Elbow Evaluation (PRTEE), subjective elbow score (SES), palpation and provocation pain, satisfaction, and complications of treatment were measured at baseline and two months after treatment. Paired t-tests and Fisher's exact tests were used for calculating the difference between pre- and post-treatment outcomes. Results: Fifty-five elbows were analyzed. Mean time between pre- and post-treatment was 11.1 weeks (standard deviation [SD], 8.9 weeks). The mean PRTEE score decreased from 68.2 (SD, 15.7) before surgery to 53.2 (SD, 25.9; p<0.001) after. The mean SES improved from 36.9 (SD, 20.8) to 51.7 (SD, 27.4; p<0.001). Despite this improvement, only 44.7% of patients showed relevant clinical improvement in PRTEE, and 37.3% showed significant clinical improvement based on SES. Four patients reported a complication and the injection disposable failed three times. Conclusions: Ultrasound-standardized autologous blood injection using the ITEC device is not an effective tool in reducing symptoms related to LE. This study showed that only half of all patients experienced a positive effect. In this heterogeneous cohort of patients, we showed no added value of ultrasound standardization.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제27권3호
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• pp.186-195
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• 2024

Purpose: Infantile colic diagnostic criteria were established by Rome IV. A universally accepted management remains to be established. We aimed to evaluate diagnostic criteria, management strategies, and perceived regional prevalence of infantile colic in Pakistan, as well as its effect on physicians and parents. Methods: A questionnaire was distributed amongst 1,256 physicians. Results: We received 800 replies. Wessel and Rome IV criteria were used by most physicians for diagnosis; however, the response "any infant who cries a lot" was selected by older physicians (48% of those over 60 years), physicians in rural areas (32%), physicians practicing in private clinics (27%), and general physicians (30%). Estimated prevalence of infantile colic ranges from 21-40%. Reassurance was the most widely recommended management strategy followed by herbal teas (51%), switching to a different formula (49%), probiotics (28%) and antibiotics (26%), discontinuation of breastfeeding (14%), elimination of dairy products from the breastfeeding mothers' diet (6%), and the administration of colic drops (1%). Most physicians considered the negative impact of colic on their personal lives and the parents as mild-to-moderate. Notably, 38% of percent of physicians routinely screened for maternal depression, and 45% of physicians were aware of the association between infantile colic and shaken baby syndrome. Conclusion: Most physicians in Pakistan diagnose and manage infantile colic according to the established guidelines. However, the guidelines pertaining to treatment planning are not followed. Educational efforts directed toward general physicians and doctors practicing in rural areas and clinics must be implemented to avoid unnecessary testing and treatment burden.