798 research outputs found
A contrastive corpus analysis on the use of connectors in students writing from 10 Asian countries as compared to native experts: Research from the ICNALE (The International Corpus Network of Asian Learners of English)
My dissertation focuses on the connector use in the writings of the Asian students from 10 different countries in comparison with that of the English native speakers. Specifically, I examine how the Asian students use the connectors similarly or differently compared to English speakers in terms of frequency and choice, depending on their respective countries and English proficiency levels. The research questions addressed in this study are these: Is there a similarity in the use of connectors between the writing of college students in 10 Asian countries and native speakers (NS) of English, in terms of frequency and choice of connector? If there is, how do they employ the connectors similarly? Is there a difference in the use of connectors between the writing of college students in 10 Asian countries and native speakers of English in terms of frequency and choice of connectors? If so, how do they employ the connectors differently? Is there a difference in the use of connectors between the writings of college students within 10 Asian countries depending their English proficiency level and their nationalities? In responding these questions, I use the written essay module of the ICNALE (the International Corpus Network of Asian Learners of English), which is available to the public. Two computational tools (Coh-Metrix and AntConc) are used to analyze and identify the commonality and difference on connector usage among the different language groups.The current study reveals the similarities and differences with which the Asian students and the English speakers use the connectors. One major finding suggests that the Asian students underuse additive and negative connectors compared to their English counterparts and that they prefer to position certain connectors at sentence-initial positions. By signposting the Asian students writing patterns as compared to the norm of the English speakers, my dissertation aims to heighten the awareness of connector use and offer some helpful information to language learners and present an important instructional resource to ESL educators and textbook designers about the authentic use of English
ΔNp63 REGULATES A COMPLEX NETWORK OF TARGET GENES IN LIMB AND EPIDERMAL DEVELOPMENT
The skin is composed of two major compartments, the dermis and epidermis. The epidermis forms a barrier to protect the body. The stratified epithelium has self-renewing capacity throughout life, and continuous turnover is mediated by stem cells in the basal layer. p63 is structurally and functionally related to p53. In spite of their structural similarities, p63 is critical for the development and maintenance of stratified epithelial tissues, unlike p53. p63 is highly expressed in the epidermis and previously has been shown to play a critical role in the development and maintenance of the epidermis. The study of p63 has been complicated due to the existence of multiple isoforms: those with a transactivation domain (TAp63) and those lacking this domain (ΔNp63). Mice lacking p63 cannot form skin, have craniofacial and skeletal defects and die within hours after birth. These defects are due to the ability of p63 to regulate multiple processes in skin development including epithelial stem cell proliferation, differentiation, and adherence programs. To determine the roles of these isoforms in skin development and maintenance, isoform specific p63 conditional knock out mice were generated by our lab. TAp63-/- mice age prematurely, develop blisters, and display wound-healing defects that result from hyperproliferation of dermal stem cells. That results in premature depletion of these cells, which are necessary for wound repair, that indicates TAp63 plays a role in dermal/epidermal maintenance. To study the role of ΔNp63, I generated a ΔNp63-/- mouse and analyzed the skin by performing immunofluorescence for markers of epithelial differentiation. The ΔNp63-/- mice developed a thin, disorganized epithelium but differentiation markers were expressed. Interestingly, the epidermis from ΔNp63-/- mice co-expressed K14 and K10 in the same cell suggesting defects in epidermal differentiation and stratification. This phenotype is reminiscent of the DGCR8fl/fl;K14Cre and Dicerfl/fl;K14Cre mice skin. Importantly, DGCR8-/- embryonic stem cells (ESCs) display a hyperproliferation defect by failure to silence pluripotency genes. Furthermore, I have observed that epidermal cells lacking ΔNp63 display a phenotype reminiscent of embryonic stem cells instead of keratinocytes. Thus, I hypothesize that genes involved in maintaining pluripotency, like Oct4, may be upregulated in the absence of ΔNp63. To test this, q-RT PCR was performed for Oct4 mRNA with wild type and ΔNp63-/- 18.5dpc embryo skin. I found that the level of Oct4 was dramatically increased in the absence of ΔNp63-/-. Based on these results, I hypothesized that ΔNp63 induces differentiation by silencing pluripotency regulators, Oct4, Sox2 and Nanog directly through the regulation of DGCR8. I found that DGCR8 restoration resulted in repression of Oct4, Sox2 and Nanog in ΔNp63-/- epidermal cells and rescue differentiation defects. Loss of ΔNp63 resulted in pluripotency that caused defect in proper differentiation and stem cell like phenotype. This led me to culture the ΔNp63-/- epidermal cells in neuronal cell culture media in order to address whether restoration of DGCR8 can transform epidermal cells to neuronal cells. I found that DGCR8 restoration resulted in a change in cell fate. I also found that miR470 and miR145 play a role in the induction of pluripotency by repressing Oct4, Sox2 and Nanog. This indicates that ΔNp63 induces terminal differentiation through the regulation of DGCR8
A Distributed ADMM Approach to Non-Myopic Path Planning for Multi-Target Tracking
This paper investigates non-myopic path planning of mobile sensors for
multi-target tracking. Such problem has posed a high computational complexity
issue and/or the necessity of high-level decision making. Existing works tackle
these issues by heuristically assigning targets to each sensing agent and
solving the split problem for each agent. However, such heuristic methods
reduce the target estimation performance in the absence of considering the
changes of target state estimation along time. In this work, we detour the
task-assignment problem by reformulating the general non-myopic planning
problem to a distributed optimization problem with respect to targets. By
combining alternating direction method of multipliers (ADMM) and local
trajectory optimization method, we solve the problem and induce consensus
(i.e., high-level decisions) automatically among the targets. In addition, we
propose a modified receding-horizon control (RHC) scheme and edge-cutting
method for efficient real-time operation. The proposed algorithm is validated
through simulations in various scenarios.Comment: Copyright 2019 IEEE. Personal use of this material is permitted.
Permission from IEEE must be obtained for all other uses, in any current or
future media, including reprinting/republishing this material for advertising
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this work in other work
Sleep problems in children and adolescents at pediatric clinics
PurposeTo investigate the frequency of childhood sleep problems at pediatric clinics in Seoul and Gyeonggi provinces.MethodsChildren (n=936) and their parents who visited 5 primary and 1 secondary pediatric outpatient clinics were invited to complete a Pediatric Sleep Questionnaire.ResultsAmong patients, 901 (96.3%) answered questionnaires in sufficient detail for evaluation. The participant's mean age was 4.35±3.02 years (range, 0–18 years). The male to female ratio was 1:0.93 (466 boys, 435 girls). Habitual snoring (>3 day/week) was reported in 16.9% of the participants. The prevalence of habitual snoring in children 2 years. Insomnia was reported in 13.2% of children. The prevalence of sleepwalking, night terrors, and bruxism, is 1.6%, 19%, and 21.1%, respectively. Snoring was associated with increased incidence of sleepwalking, night terrors, and bruxism. Age was associated with insomnia and habitual snoring (P<0.05). Insomnia was more prevalent in younger (21%) than in older children (6%). Snoring was more frequent in both preschool (34%) and school-aged children (33%). The frequency of sleep disordered breathing and insomnia did not vary significantly with gender. However, snoring was more prevalent in boys.ConclusionSleep problems are frequent among children in Korea. Children with snoring have an increased risk of sleepwalking, night terror, and bruxism. Primary clinicians should consider children's sleep habits to improve their health
Possible association of norepinephrine transporter -3081(A/T) polymorphism with methylphenidate response in attention deficit hyperactivity disorder
Background
Attention-deficit/hyperactivity disorder (ADHD) is a heritable disorder characterized by symptoms of inattention and/or hyperactivity/impulsivity. Methylphenidate (MPH) has been shown to block the norepinephrine transporter (NET), and genetic investigations have demonstrated that the norepinephrine transporter gene (SLC6A2) is associated with ADHD. The aims of this study were to examine the association of the SLC6A2 -3081(A/T) and G1287A polymorphisms with MPH response in ADHD.
Methods
This study enrolled 112 children and adolescents with ADHD. A response criterion was defined based on the Clinical Global Impression-Improvement (CGI-I) score, and the ADHD Rating Scale-IV (ARS) score was also assessed at baseline and 8 weeks after MPH treatment.
Results
We found that the subjects who had the T allele as one of the alleles (A/T or T/T genotypes) at the -3081(A/T) polymorphism showed a better response to MPH treatment than those with the A/A genotype as measured by the CGI-I. We also found a trend towards a difference in the change of the total ARS scores and hyperactivity/impulsivity subscores between subjects with and without the T allele. No significant association was found between the genotypes of the SLC6A2 G1287A polymorphism and response to ADHD treatment.
Conclusion
Our findings provide evidence for the involvement of the -3081(A/T) polymorphism of SLC6A2 in the modulation of the effectiveness of MPH treatment in ADHD
Magnetic Resonance Imaging Compatibility of the Polymer-based Cochlear Implant
ObjectivesIn this study, we compared the magnetic resonance (MR) image artifacts caused by a conventional metal-based cochlear implant and a newly developed liquid crystal polymer (LCP)-based device.MethodsThe metal-based cochlear implant system (Nurobiosys Co.) was attached to side of the head of a subject and the LCP-based device was attached to opposite side. In both devices, alignment magnets were removed for safety. Magnetic resonance imaging (MRI) was performed on a widely used 3.0 T and an ultra-high 7.0 T MRI machine. 3.0 and 7.0 T MR images were acquired using T1- and T2*-weighted gradient echo sequences, respectively.ResultsIn the 3.0 T images, the metal-based device on the left side generated the significant amount of artifacts. The MR images in the proximity of the metal package were obscured by the artifacts in both axial and sagittal views. On the other hand, the MR images near the LCP-based device were relatively free from the artifacts and clearly showed the brain structures. 7.0 T MR images showed the more severe distortion in the both sides but the metal-based cochlear implant system caused a much larger obscure area than the LCP-based system.ConclusionThe novel LCP-based cochlear implant provides a good MRI compatibility beyond present-day cochlear implants. Thus, MR images can be obtained from the subjects even with the implanted LCP-based neural prosthetic systems providing useful diagnostic information. Furthermore, it will be also useful for functional MRI studies of the auditory perception mechanism after cochlear implantations as well as for positron emission tomography-MRI hybrid imaging
Strong carrier localization and diminished quantum-confined Stark effect in ultra-thin high-indium-content InGaN quantum wells with violet light emission
Here, we report on the optical and structural characteristics of violet-light-emitting, ultra-thin, high-Indium-content (UTHI) InGaN/GaN multiple quantum wells (MQWs), and of conventional low-In-content MQWs, which both emit at similar emission energies though having different well thicknesses and In compositions. The spatial inhomogeneity of In content, and the potential fluctuation in high-efficiency UTHI MQWs were compared to those in the conventional low-In-content MQWs. We conclude that the UTHI InGaN MQWs are a promising structure for achieving better quantum efficiency in the visible and near-ultraviolet spectral range, owing to their strong carrier localization and reduced quantum-confined Stark effect.open0
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