The odd primary order of the commutator on low rank Lie groups

Let $G$ be a simply-connected, compact, simple Lie group of low rank relative to a fixed prime $p$. After localization at $p$, there is a space $A$ which "generates" $G$ in a certain sense. Assuming $G$ satisfies a homotopy nilpotency condition relative to $p$, we show that the Samelson product $\langle Id_G, Id_G\rangle$ of the identity of $G$ equals the order of the Samelson product $\langle\imath,\imath\rangle$ of the inclusion $\imath:A\to G$. Applying this result, we calculate the orders of $\langle Id_G,Id_G\rangle$ for all $p$-regular Lie groups and give bounds on the orders of $\langle Id_G,Id_G\rangle$ for certain quasi-$p$-regular Lie groups.Comment: 18 pages; Accepted by Topology and its Application

A comparative study on two aspheric lenses: Biomedic 55 aspheric and frequency 55 aspheric

Background: It has been suggested that aspheric contact lenses may provide better visual performance than conventional spherical soft contact lenses. Previous studies conducted on Aspheric lenses found that they may be masking some astigmatism resulting in better vision. However, other studies have not supported this finding and instead found that Aspheric lenses may mask spherical aberration, providing better vision. In this study we compare the visual performance of two Aspheric lenses: Frequency 55 Aspheric and Biomedic Premium, to determine whether visual performance differs between them. Methods: This study was a randomized, double blind in which the subjects wore two different aspheric lenses Cooper Vision Frequency 55 Aspheric and Biomedic Aspheric Premium for at least eight hours. We recruited seventeen optometry students from Pacific University who were current soft contact lens wearers. For both lenses, high and low contrast visual acuity were taken with their natural pupil size, subjective quality of vision was assessed with a questionnaire, and high contrast visual acuity was measured while the patient was dilated through a 3mm and a 6mm aperture to control pupil size. Results: Objectively we found that there are no differences in visual performance between the two lenses. Subjectively, we found that patients preferred the vision of Biomedic Premium lenses over Frequency 55 Aspheric. Conclusions: What ultimately will dictate which lens the patient will wear is based on patient comfort and fit. Based on our study Biomedics was subjectively preferred over the Frequency 55 Aspheric

Electroacupuncture provides a new approach to neuroprotection in rats with induced glaucoma

Objectives: To investigate, using multifocal electroretinogram (mfERG), the effect of electroacupuncture (EA) on retinal function in rats with experimental glaucoma. Design and subjects: Glaucoma was induced in the right eyes of 15 adult female Sprague-Dawley rats by laser photocoagulation for three quarters of the perilimbal and episcleral vessels. The left eye of each rat was used as the control. The animals were divided into 3 groups: no treatment (non-EA control group), 2 Hz EA group, and 100 Hz EA group. EA treatment at different frequencies can produce different levels of analgesia and hence the effect of EA with different frequencies on glaucoma treatment was investigated. Both eyes of each rat in the EA experimental groups received 3 EA treatment sessions each week for 4 weeks. The retinal function was measured using mfERG after 4 weeks of EA treatment. Results: There was no significant difference in the amplitude (both N1 trough and P1 peak) of mfERG first- order kernel response between the treatment and control groups. In determining the waveform characteristics by the ratio of N1 amplitude to P1 amplitude (N/P ratio), obvious differences were found in the N/P ratio between the control eyes and the glaucoma eyes in the non-EA group and the 100 Hz EA treatment group, but similar values in the N/P ratio were observed between the control eyes and the glaucoma eyes in the 2 Hz EA treatment group. The waveform from the eyes with glaucoma was deformed in both the non-EA group and the 100 Hz EA group, but the waveform from the glaucomatous eye was preserved in the 2 Hz EA group. Conclusions: Application of EA at 2 Hz provides neuroprotection by preserving retinal function in rats with experimental glaucoma. Low frequency EA may be an alternative therapy in the treatment of glaucoma. © Mary Ann Liebert, Inc.published_or_final_versio

The acquisition of Cantonese classifiers by preschool children in Hong Kong

The Cantonese language has a complex classifier system and young learners need to pay attention to both the semantics and syntax of classifiers. This study investigated the repertoire of classifiers produced by 492 Cantonese-speaking preschoolers in three age groups (3 ;0, 4 ;0 and 5 ;0). Spontaneous utterances produced in 30-mmute toy-play contexts were collected and transcribed. Analyses identified a productive repertoire of 73 classifiers in the utterances, which could be appropriately classified into the typology proposed in the present study. An age-related increase in the number of classifier types per child as well as the repertoire size of each group was found. g03 (CL) was widely used as the general classifier by the young children. It was also discovered that the three-year-olds were already showing signs of grasping the basic syntax of classifiers. Cognitive, linguistic and contextual influences presumed to shape the evidence are discussed. © 2007 Cambridge University Press.published_or_final_versio

Histiocytic sarcoma simulating immune thrombocytopenic purpura

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Asking for action or information? Crosslinguistic comparison of interrogative functions in early child Cantonese and Mandarin

Request for information (RfI) is believed to be the universally dominant function of young children’s questioning, whereas request for action (RfA) has been reported to be the leading interrogative form used in early child Cantonese. The possibility of crosslinguistic variability prompts further research and comparison with additional languages. This study compares the interrogatives elicited from two early Chinese language corpora: Early Childhood Cantonese Corpus (ECCC) and Early Childhood Mandarin (ECMC). Altogether, 1214 and 942 question types were elicited from ECCC and ECMC, respectively. Analyses indicated that: (1) all the interrogative functions identified in an earlier study of Cantonese were also observed in the early Mandarin interrrogatives; and (2) both RfA (49.9%) and RfI (45.5%) were the most frequently observed functions of early child Chinese interrogatives. This crosslinguistic evidence suggests that follow-up studies are needed to further explore the possible influences of language, culture and communication tasks on children’s uses of interrogative forms.postprin