Transactional distance and student motivation: Student perception of teacher immediacy, solidarity toward peer students and student motivation in distance education

Transactional Distance Theory is conceptually significant in that the core nature of distance in distance education is not a geographical or temporal distance but a psychological or communicational distance between students and their teacher(s), as well as among students. In spite of the conceptual significance of the transactional distance theory, the interrelationships among the construct variables and propositions of the theory are unclear. The majority of studies on transactional distance theory either used the theory solely as a conceptual framework, or proposed the refinement of the theory. Literature review indicated that the theory was found to be invalid and unreliable. No measurements have been consistently used to measure transactional distance.;This study focused on the conceptual significance of transactional theory through the use of concepts and measurements from Communication Studies. This study made an effort to investigate Moore\u27s theory of transactional distance with the concepts of \u27immediacy\u27 and \u27solidarity,\u27 which are often used in the field of Communication Studies. The operational definition of transactional distance between teacher and students (TDST) is students\u27 perception of teachers\u27 immediacy behavior and that of transactional distance among students (TDSS) is students\u27 perception of the learner.;By providing a measurable communication variable as operational definition of transactional distance, this study showed the potential of transactional distance as a measurable variable in a theory. This study sampled seventy-nine Executive Master\u27s of Business Administration (EMBA) students in videoconferencing classrooms. The findings indicated that offsite students who do not have their instructor in their classroom developed higher solidarity toward their classmates in the same site than onsite students whose instructors were present in their classroom. No significant association was found between student motivation and student perception of psychological distance toward their instructor or toward their classmates

EXOT: Exit-aware Object Tracker for Safe Robotic Manipulation of Moving Object

Current robotic hand manipulation narrowly operates with objects in predictable positions in limited environments. Thus, when the location of the target object deviates severely from the expected location, a robot sometimes responds in an unexpected way, especially when it operates with a human. For safe robot operation, we propose the EXit-aware Object Tracker (EXOT) on a robot hand camera that recognizes an object's absence during manipulation. The robot decides whether to proceed by examining the tracker's bounding box output containing the target object. We adopt an out-of-distribution classifier for more accurate object recognition since trackers can mistrack a background as a target object. To the best of our knowledge, our method is the first approach of applying an out-of-distribution classification technique to a tracker output. We evaluate our method on the first-person video benchmark dataset, TREK-150, and on the custom dataset, RMOT-223, that we collect from the UR5e robot. Then we test our tracker on the UR5e robot in real-time with a conveyor-belt sushi task, to examine the tracker's ability to track target dishes and to determine the exit status. Our tracker shows 38% higher exit-aware performance than a baseline method. The dataset and the code will be released at https://github.com/hskAlena/EXOT.Comment: 2023 IEEE International Conference on Robotics and Automation (ICRA

Effects of pre-existing hydrogen to stress triaxiality and damage evolution on ultra high strength steel

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The COOH-terminus of TM4SF5 in hepatoma cell lines regulates c-Src to form invasive protrusions via EGFR Tyr845 phosphorylation

AbstractTransmembrane 4 L six family member 5 (TM4SF5) enhances cell migration and invasion, although how TM4SF5 mechanistically mediates these effects remains unknown. In the study, during efforts to understand TM4SF5-mediated signal transduction, TM4SF5 was shown to bind c-Src and thus hepatoma cell lines expressing TM4SF5 were analyzed for the significance of the interaction in cell invasion. The C-terminus of TM4SF5 bound both inactive c-Src that might be sequestered to certain cellular areas and active c-Src that might form invasive protrusions. Wildtype (WT) TM4SF5 expression enhanced migration and invasive protrusion formation in a c-Src-dependent manner, compared with TM4SF5-null control hepatoma cell lines. However, tailless TM4SF5ΔC cells were more efficient than WT TM4SF5 cells, suggesting a negative regulatory role by the C-terminus. TM4SF5 WT- or TM4SF5ΔC-mediated formation of invasive protrusions was dependent or independent on serum or epidermal growth factor treatment, respectively, although they both were dependent on c-Src. The c-Src activity of TM4SF5 WT- or TM4SF5ΔC-expressing cells correlated with enhanced Tyr845 phosphorylation of epidermal growth factor receptor. Y845F EGFR mutation abolished the TM4SF5-mediated invasive protrusions, but not c-Src phosphorylation. Our findings demonstrate that TM4SF5 modulates c-Src activity during TM4SF5-mediated invasion through a TM4SF5/c-Src/EGFR signaling pathway, differentially along the leading protrusive edges of an invasive cancer cell

Allelic and Haplotypic Diversity of HLA-A, -B, -C, and-DRB1 Genes in Koreans Defined by High-resolution DNA Typing

배경 : HLA 형별은 혈청학적 수준(generic level)에서도 다형성이 심하지만 대립유전자 수준에서는 더욱 심한 다형성을 보이고 인종 간에 큰 차이를 나타내는 것으로 알려졌다. 본 연구에서는 고해상도 DNA 검사법을 이용하여 한국인에서 HLA대립유전자 형별과 일배체형의 종류 및 빈도를 알아보고자 하였다. 방법 : 건강한 한국인 474명을 대상으로 HLA-A, -B, -C, -DRB1 유전자에 대해 두 단계의 검사로 대립유전자(4자리수) 형별 분석을 실시하였다. 1단계로 혈청학적 수준의 형별검사를 혈청학적 검사법이나 sequence-specific oligonucleotide(PCR-SSO) 방법으로 시행하였고, 그 다음 단계로 대립유전자 형별검사를 class I은 exon 2와 exon3, DRB1은 exon 2에 대해 single-strand conformation polymorphism (PCR-SSCP) 또는 직접염기서열분석법을 이용하여 실시하였다. HLA 대립 유전자의 유전자 빈도, 일배체형 빈도, 연쇄불평형 값은 maximum likelihood 원리에 근거한 제11차 국제조직적합성워크숍 컴퓨터 프로그램을 이용하여 산출하였다. 결과 : 한국인에서 검출된 HLA-A, -B, -C, DRB1 대립유전자 형별은 각각 21, 40, 22, 29종이었다. 이 중에 유전자 빈도 10% 이상을 보인 대립유전자 형별(빈도순 나열)은 A*02:01, A*24:02, A*33:03; B*51:01; C*01:02, C*03:03; RB1*09:01등이었다. HLA 일배체형의 분석 결과 0.5% 이상의 빈도를 나타내는 2-유전자좌 일배체형은 A-C 44종, B-C 42종, A-B 51종, B-DRB1 52종이었고, 3-유전자좌 일배체형은 A-C-B 42종, A-B-DRB1 34종이었다. 한국인에서 빈도 1% 이상의 A-B-DR 일배체형은 13종으로, 전체 일배체형의 26.0%를 차지하였고, 2% 이상으로 가장 흔한 A-B-DR 일배체형은 A*33:03-B*44:03-DRB1*13:02 (3.7%), A*33:03-B*44:03-DRB1*07:01 (3.0%), A*33:03-B*58:01-DRB1*13:02 (3.0%), A*24:02-B*07:02-DRB1*01:01 (2.8%), A*30:01-B*13:02-DRB1* 07:01 (2.3%), A*11:01-B*15:01-DRB1*04:06 (2.2%) 등 6종이었다. 결론 : 본 연구를 통해 한국인의 대립유전자 수준의 HLA 형별과 HLA 일배체형 빈도에 대한 자료를 제시하였으며, 본 연구의 결과는 한국인에서 장기이식, 질환연관성 연구, 인류유전학적 연구 등에서 중요한 기초자료로 이용될 수 있을 것으로 기대된다. Background : In this study, we used high-resolution DNA typing to investigate the distribution of HLA alleles and haplotypes in Koreans. Methods : HLA-A, -B, -C, and -DRB1 alleles were genotyped at the allelic (4-digit) level in 474 healthy Koreans. HLA genotyping was performed in two steps. Initially, serologic typing or generic-level DNA typing was performed using the FOR-sequence-specific oligonucleotide method, and then allelic DNA typing (exons 2 and 3 for class I, and exon 2 for DRB1) was carried out using the FOR-single-strand conformation polymorphism method or sequence-based typing. HLA allele and haplotype frequencies and linkage disequilibrium values were calculated by the maximum likelihood method using a computer program developed for the 11th International Histocompatibility Workshop. Results : A total of 21 HLA-A, 40 HLA-B, 22 HLA-C, and 29 HLA-DRB1 alleles were found in Koreans. The most frequent alleles in each locus with frequencies of >= 10% were, in decreasing order of frequency, as follows: A star 24:02, A star 02:01, A(star)33:03; B(star)51:01; C(star)01:02, C(star)03:03; and DRB1(star)09:01. The numbers of two- and three-locus haplotypes with frequencies of >0.5% were as follows: 44 A-C, 42 B-C, 51 A-B, 52 B-DRB1, 42 A-C-B, and 34 A-B-DRB1. Thirteen A-B-DRB1 haplotypes with frequencies of >= 1.0% comprised 26.0% of the total haplotypes. The six most common haplotypes were as follows: A(star)33:03-B(star)44:03-DRB1(star)3:02 (3.7%), A(star)33:03-B(star)44:03-DRB1(star)07:01 (3.0%), A(star)33:03-B(star)58: 01-DRB1(star)13:02 (3.0%), A(star)24:02-B(star)07:02-DRB1(star)01:01 (2.8%), A(star)30:01-B(star)13:02-DRB1(star)07:01 (2.3%), and A(star)11:01-B(star)15:01-DR81(star)04:06 (2.2%). Conclusions : The information obtained in this study can be used as basic data for Koreans in the fields of organ transplantation, disease association, and anthropologic studies. 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Surgical ciliated cyst of the mandible after orthognathic surgery: a case report with review of the literature

Background : Surgical ciliated cysts, also known as postoperative maxillary cysts or implantation cysts, occur mainly in the posterior maxilla after radical maxillary sinus surgery; they rarely develop in the mandible. They are thought to occur when the sinonasal epithelium is infiltrated by a surgical instrument during surgery or as a result of transplantation of bone or cartilage with respiratory epithelium attached. Case presentation : We report a case in which a surgical ciliated cyst developed in the anterior part of the mandible, presumably as a result of bimaxillary orthognathic surgery and genioplasty performed 24 years earlier. We then review the few similar cases reported in the literature. Conclusion : Surgical ciliated cysts in the mandible are extremely rare, but they could occur after simultaneous surgery on the maxilla and mandible, even decades later. To prevent surgical ciliated cysts in the mandible, we recommend that the surgical instruments, especially the saw blade used during bimaxillary surgery, be new or cleaned and that previously placed plates and screws be removed at an appropriate time

Altered resting-state connectivity in subjects at ultra-high risk for psychosis: an fMRI study

<p>Abstract</p> <p>Background</p> <p>Individuals at ultra-high risk (UHR) for psychosis have self-disturbances and deficits in social cognition and functioning. Midline default network areas, including the medial prefrontal cortex and posterior cingulate cortex, are implicated in self-referential and social cognitive tasks. Thus, the neural substrates within the default mode network (DMN) have the potential to mediate self-referential and social cognitive information processing in UHR subjects.</p> <p>Methods</p> <p>This study utilized functional magnetic resonance imaging (fMRI) to investigate resting-state DMN and task-related network (TRN) functional connectivity in 19 UHR subjects and 20 matched healthy controls. The bilateral posterior cingulate cortex was selected as a seed region, and the intrinsic organization for all subjects was reconstructed on the basis of fMRI time series correlation.</p> <p>Results</p> <p>Default mode areas included the posterior/anterior cingulate cortices, the medial prefrontal cortex, the lateral parietal cortex, and the inferior temporal region. Task-related network areas included the dorsolateral prefrontal cortex, supplementary motor area, the inferior parietal lobule, and middle temporal cortex. Compared to healthy controls, UHR subjects exhibit hyperconnectivity within the default network regions and reduced anti-correlations (or negative correlations nearer to zero) between the posterior cingulate cortex and task-related areas.</p> <p>Conclusions</p> <p>These findings suggest that abnormal resting-state network activity may be related with the clinical features of UHR subjects. Neurodevelopmental and anatomical alterations of cortical midline structure might underlie altered intrinsic networks in UHR subjects.</p