Sex-specific association of hair cortisol concentration with stress-related psychological factors in healthy young adults

Background: Hair cortisol concentration (HCC) has received attention as a useful marker of stress, but evidence on associations between psychological factors and cortisol concentration is inconsistent. The purpose of this study was to investigate the sex differences in the relationship between cortisol concentration and psychological factors in healthy young adults. Methods: A total of 205 (103 females, 102 males) healthy young adults participated. HCC and various stress-related psychological measures were compared between sexes. Multiple linear regression analyses were performed to assess associations between HCC and stress-related psychological measures for all participants and for each sex. Results: The difference in HCC according to sex was not significant. The reported number of stressful life events in the past year, stress perception, depressive and anxiety-related symptoms, and emotion dysregulation were not different between sexes, either. The association between HCC and emotion dysregulation was significant in females but not males. Conclusion: We observed a sex-specific association between HCC and psychological factors. Our findings may imply that HCC could be a useful biomarker of stress and stress-related emotion dysregulation in healthy young women.ope

비트켄슈타인；규칙과 사적 언어 에 나타난 의미회의주의에 대한 비판: 의미회의주의로부터 의미를 구조하기

우리는 특정 단어를 사용하여 특정 대상을 의미한다는 사실 혹은 그러한 사실의 존재를 너무나 당연하게 받아들이기 쉽다. 그러나 크립키는 그의 책 『비트겐슈타인－ 규칙과 사적 언어』에서 우리가 당연시해왔던 표현 p로 p를 의미한다는 사실이 존재하지 않는다는 놀라운 주장을 편다. 예를 들어, 더하기라는 표현에 대해 우리는 더하기 로 더하기를 의미해왔고 또 지금 의미할 수 있다고－너무나 당연하게도!－생각한다. 따라서 우리는 우리가 한 번도 해 보지 않은 계산, 가령 68 더하기 57이 그런 계산일 때 그러한 계산에 대해 망설임 없이 125가 답이라고 생각한다. 진실로 우리가 더하기로 더하기를 의미했다면 그러한 사실로부터 우리의 답은 정당화될 것이다. 그러나 회의주의자는 우리가 68 더하기 57에 5라고 답해야 한다고 주장한다. 회의주의자에 따르면 우리가 더하기 로 의미해왔던 것은 사실 겹하기 함수라는 것이다. 겹하기 함수란 x 더하기 y형태의 계산이 주어졌을 때, x와 y가 57보다 작은 수를 가리키면 x와 y를 더한 결과를 답으로 내놓고, x와 y가 57과 57보다 큰 수를 가리킨다면 5를 답으로 내놓는 그런 함수이다. 회의주의자의 주장은 우리에게 너무나 터무니없는 이야기처럼 들린다. 우리는 더하기로 더하기를 의미해왔고 그러므로 과거의 그런 의도에 따른다면 나는 68더하기 57에125라고 답해야 한다. 그러나 회의주의자에게 항의하거나 혹은 회의주의자의 주장을 무시하기 전에 한 번 생각해보라, 과연 우리가더하기 로 더하기를 의미해왔음을 보증해줄 수 있는 사실이 존재하 는가

초고강도 열연 강판의 변형률 집중 동반 유무에 따른 파단 예측

학위논문 (박사)-- 서울대학교 대학원 : 재료공학부, 2017. 2. 정관수.Numerical analysis is commonly applied to predict failure and optimize forming process in the industrial sheet metal forming. In most of typical sheet forming processes at room temperature, the metal sheets fail to deform after strain localization in the thinning mode. This strain localization is a result of the boundary value problem of the force equilibrium condition, which is strongly affected by the following three mechanical properties: the hardening behavior, yield function and strain-rate sensitivity. However, some rather brittle metals fail without strain localization. It would be determined by the fracture criterion in principle, which is one of mechanical properties. Ultimately, failure is a result of competition between two sets of properties, the first set is the fracture criterion, which directly controls failure and the other consists of the three properties, which affect strain localization. The main object of this work is to predict failure of rather thick advanced high strength hot-rolled steel sheets depending on the existence of strain localization. As for the failure with strain localization, a new numerical procedure to evaluate the formability of rather thick advanced high strength hot-rolled steel sheets was developed in this work. The new procedure differs from the practice commonly applied for rather thin cold-rolled metal sheets with four main features: employing 3-D continuum elements, non-quadratic yield functions such as Yoshida and Hosford yield functions and hardening with its deterioration (or ultimate softening) beyond uniform deformation limit as well as directly monitoring strain localization to determine failure without employing any forming limit criterion (unlike the common practice for cold-rolled sheets, which typically employs shell elements, Hills quadratic yield function, extrapolated hardening and forming limit criterion). The characterization of material properties for the new procedure involves the simple tension, disk compression and hemispherical dome stretching tests. In case of failure without localization, to properly predict the formability, the strain rate effect and fracture criterion, which is dependent on stress triaxiality and strain rate, were considered. The stress triaxiality and strain rate dependent fracture criterion was characterized based on tensile tests of four different shape specimens to cover the wide range of deformation mode with various strain rates. From the experiments, the numerical and experimental punch force and displacement results were compared and the effective fracture strain was determined. For application and validation, advanced high strength hot-rolled steel sheets, HB780 and DP780 with the thickness of 2.9 mm for failure with strain localization and TWIP980 with the thickness of 3.1mm for failure without strain localization, were considered for the circular cup drawing test.1 Introduction 1 2 Theory 9 2.1 Yield function 9 2.1.1 Hill1948 yield function 9 2.1.2 Hosford yield function 10 2.1.3 Yoshida yield function 12 2.2 Fracture criterion 17 3 Material Characterization 18 3.1 Failure with strain localization 18 3.1.1 Simple tension test 18 3.1.2 Disk compression test 26 3.1.3 Yield function 28 3.1.4 Inverse calibration of hardening deterioration with the simpe tension 34 3.1.5 Hemispherical dome stretching test 41 3.2 Failure without strain localization 59 3.2.1 Simple tension test 59 3.2.2 Strain rate sensitivity 66 3.2.3 Fracture test 72 3.2.4 Triaxiality and strain rate dependent fracture criterion 75 4 Validation 93 5 Conclusions 124 Bibliography 127 Korean Abstract 131Docto

딥 비주얼라이제이션을 통한 시각화 이디엄의 이해

학위논문 (석사)-- 서울대학교 대학원 : 공과대학 컴퓨터공학부, 2018. 2. 서진욱.Visualization (vis) idioms define the way visual representations are created and manipulated. Well-known vis idioms include familiar charts such as bar charts and pie charts. Vis research and applications require thorough understanding of vis idioms. As a medium to understand vis idioms, I suggest a novel approach that employs deep visualization. Deep visualization is a collective name of methods for visualizing the characteristics of neurons in deep neural networks by generating their preferred stimuli (images). In this paper, I present two neural networks, one classifying the type of vis idioms, and one generating images of given idiom type. By applying deep visualization on the neural classifier through the neural generator, I examine how deep visualization can help vis researchers understand diverse aspects of vis idioms in novel ways and potentially derive unexplored idioms.Chapter 1 Introduction 1 Chapter 2 Related Work 4 2.1 Point-based Visualization 4 2.2 Visualization Idioms 8 Chapter 3 Architecture 10 3.1 Dataset 10 3.2 Classier 11 3.3 Noiseless Joint PPGN-h 14 3.4 PP-BEGAN 15 Chapter 4 Exploratory Study 21 4.1 Sampling Results 21 4.2 Qualitative Analysis 23 4.3 Walking in the latent space 26 Chapter 5 Discussion and Future Work 32 Chapter 6 Conclusion 34 References 36 국문초록 42Maste

Effect of Childhood Trauma on the Association Between Stress-Related Psychological Factors and Hair Cortisol Level in Young Adults

Objective: Relationship between hair cortisol concentration (HCC) and stress-related psychological measures are inconclusive, possibly due to overlooked heterogeneity regarding childhood trauma and a lack of comprehensive research on stress-related psychological factors. This study aims to compare young adults without history of childhood trauma to young adults who experienced childhood trauma using HCC and various stress-related psychological factors, as well as investigate the impacts of childhood trauma on the association between HCC and stress-related psychological measures. Methods: A total of 206 young, healthy adults were recruited. We divided participants into two groups depending on whether or not they had suffered moderate-to-severe childhood trauma (CT+ and CT-) and compared HCC and various stress-related psychological measures between groups. Using multiple linear regression analyses, we assessed the associations between HCC and stress-related psychological measures for each group. Results: We found no difference between the groups in HCC or the reported number of stressful life events in the past year; however, CT+ individuals reported higher stress perception, more depressive and anxiety-related symptoms, and more difficulties in emotion regulation than CT- individuals. HCC was associated with emotion dysregulation among the CT- individuals, but not among the CT+ individuals. Conclusion: These findings suggest that history of childhood trauma should be considered in studies using HCC as a biomarker for stress in young adults. Furthermore, HCC might be a useful biomarker of stress and stress-related emotion dysregulation in individuals without moderate-to-severe childhood trauma.ope