Theory of monolayers with boundaries: Exact results and Perturbative analysis

Domains and bubbles in tilted phases of Langmuir monolayers contain a class of textures knows as boojums. The boundaries of such domains and bubbles may display either cusp-like features or indentations. We derive analytic expressions for the textures within domains and surrounding bubbles, and for the shapes of the boundaries of these regions. The derivation is perturbative in the deviation of the bounding curve from a circle. This method is not expected to be accurate when the boundary suffers large distortions, but it does provide important clues with regard to the influence of various energetic terms on the order-parameter texture and the shape of the domain or bubble bounding curve. We also look into the effects of thermal fluctuations, which include a sample-size-dependent effective line tension.Comment: replaced with published version, 21 pages, 16 figures include

ADHD and DCD comorbidity: the associated problems

Attention Deficit-Hyperactivity Disorder (ADHD) has a high comorbidity with Development Coordination Disorder (DCD). On their own, these disorders are often associated with many other behavioural and emotional problems. However, studies investigating associated problems in this comorbid group are limited. This study examined these associated problems in children with comorbid ADHD and DCD using the Conners' Parent and Teachers' Rating Scales (CPRS-R:L; CTRS-R:L). A total of 109 participants (82 males; 27 females) with age ranging from 9.8 to 12.7 (M=11.16; SD=0.79) participated in this study. Participants were placed into 4 groups: Controls (n=41), ADHD (n=29), DCD (n=17) and comorbid ADHD/DCD (n=22), based on the scores from the Australian Disruptive Behaviours Scale, the Developmental Coordination Disorder Questionnaire and the McCarron Assessment Neuromuscular Development measure. A multivariate analysis of variance was conducted on the parent-rated and the teacher-rated Conners' test variables Anxious-Shy, Perfectionism, Social Problems and Psychosomatic separately. Results revealed that parents reported significant social problems seen in children with ADHD and comorbid ADHD/DCD. These children have few friends, experience low self-esteem and self-confidence, and they also feel emotionally distant from peers. However, teachers only reported significant social problems seen in children with comorbid ADHD/DCD. In addition, parents reported significant psychosomatic symptoms seen in children with ADHD. No significant group differences were found for the variables Anxious-Shy and Perfectionism. These findings imply that children with comorbid ADHD/DCD experience more significant social problems compared to children with only ADHD or DCD

The use of the Developmental Coordination Disorder Questionnaire in Australian children

The effectiveness of the Developmental Coordination Disorder Questionnaire (DCDQ) as a screening tool was investigated in an Australian sample. Using the DCDQ, 129 children aged 9 to 12 years old were screened for Developmental Coordination Disorder (DCD), with a follow-up assessment of movement ability using the McCarron Assessment of Neuromuscular Development (MAND) as the criterion measure. The overall decision agreement between the two measures in identifying DCD was .64. The DCDQ had a sensitivity of .55 and a specificity of .74. The low sensitivity suggests that many children with DCD are not being identified by the DCDQ despite the inclusion of children with a suspect score on the DCDQ. As a screening tool, the DCDQ was accurate in identifying children with moderate or severe DCD but identified less than half of the children with mild DCD

CONGENITAL ATLANTO-AXIAL DISLOCATION

Atlanto-axial dislocation IS an uncommon condition. It is usually secondary to trauma, infection (tuberculous and non-tuberculous atlas and axis) and rheumatoid arthritis. Othe

The use of the Developmental Coordination Disorder Questionnaire in Australian children

The effectiveness of the Developmental Coordination Disorder Questionnaire (DCDQ) as a screening tool was investigated in an Australian sample. Using the DCDQ, 129 children aged 9 to 12 years old were screened for Developmental Coordination Disorder (DCD), with a follow-up assessment of movement ability using the McCarron Assessment of Neuromuscular Development (MAND) as the criterion measure. The overall decision agreement between the two measures in identifying DCD was .64. The DCDQ had a sensitivity of .55 and a specificity of .74. The low sensitivity suggests that many children with DCD are not being identified by the DCDQ despite the inclusion of children with a suspect score on the DCDQ. As a screening tool, the DCDQ was accurate in identifying children with moderate or severe DCD but identified less than half of the children with mild DCD

Motor dysfunctions in ADHD and DCD: an examination of the error correction mechanisms

A high incidence of overlap between ADHD and DCD suggests that they may be related. However, different deficits may underlie the disorders. ADHD has response inhibition deficit whereas DCD has efference copy deficit. The present study examines the presence of these deficits in the respective disorders and within the ADHD subtypes. The ability of children to amend their hand movements during target perturbation is investigated in a double-step tracking task. Participants were children aged 10 to 12. The ADHD symptoms were screened by Australian Disruptive Behaviours Scale, Conner's Parent Rating Scale-Revised:L and Conner's Parent Rating Scale-Revised:L; DCD symptoms were screened by Developmental Coordination Disorder Questionnaire and McCarrson Assessment of Neuromuscular Development measure. ADHD-PI only, ADHD-C only, ADHD-PI with DCD, ADHD-C with DCD, DCD only, and a comparison group were studied. The participants were required to capture a target that skipped twice in succession. Compared to other groups, control children were able to adjust the initial response amplitude as a function of the time between a superseding stimulus and initiation of a response. The corrective response furthermore was accurate with respect to the final step position. The results are discussed in terms of an error averaging mechanism underlying tracking performance

Motor dysfunctions in ADHD and DCD: an examination of the error correction mechanisms

A high incidence of overlap between ADHD and DCD suggests that they may be related. However, different deficits may underlie the disorders. ADHD has response inhibition deficit whereas DCD has efference copy deficit. The present study examines the presence of these deficits in the respective disorders and within the ADHD subtypes. The ability of children to amend their hand movements during target perturbation is investigated in a double-step tracking task. Participants were children aged 10 to 12. The ADHD symptoms were screened by Australian Disruptive Behaviours Scale, Conner's Parent Rating Scale-Revised:L and Conner's Parent Rating Scale-Revised:L; DCD symptoms were screened by Developmental Coordination Disorder Questionnaire and McCarrson Assessment of Neuromuscular Development measure. ADHD-PI only, ADHD-C only, ADHD-PI with DCD, ADHD-C with DCD, DCD only, and a comparison group were studied. The participants were required to capture a target that skipped twice in succession. Compared to other groups, control children were able to adjust the initial response amplitude as a function of the time between a superseding stimulus and initiation of a response. The corrective response furthermore was accurate with respect to the final step position. The results are discussed in terms of an error averaging mechanism underlying tracking performance

Vlasov Description Of Dense Quark Matter

We discuss properties of quark matter at finite baryon densities and zero temperature in a Vlasov approach. We use a screened interquark Richardson's potential consistent with the indications of Lattice QCD calculations. We analyze the choices of the quark masses and the parameters entering the potential which reproduce the binding energy (B.E.) of infinite nuclear matter. There is a transition from nuclear to quark matter at densities 5 times above normal nuclear matter density. The transition could be revealed from the determination of the position of the shifted meson masses in dense baryonic matter. A scaling form of the meson masses in dense matter is given.Comment: 15 pages 4 figure

On a problem of Erd\H{o}s and Rothschild on edges in triangles

Erd\H{o}s and Rothschild asked to estimate the maximum number, denoted by H(N,C), such that every N-vertex graph with at least CN^2 edges, each of which is contained in at least one triangle, must contain an edge that is in at least H(N,C) triangles. In particular, Erd\H{o}s asked in 1987 to determine whether for every C>0 there is \epsilon >0 such that H(N,C) > N^\epsilon, for all sufficiently large N. We prove that H(N,C) = N^{O(1/log log N)} for every fixed C < 1/4. This gives a negative answer to the question of Erd\H{o}s, and is best possible in terms of the range for C, as it is known that every N-vertex graph with more than (N^2)/4 edges contains an edge that is in at least N/6 triangles.Comment: 8 page