85 research outputs found
Improving precision for detecting change in the shape of the cornea in patients with keratoconus
To investigate a method for precision analysis to discriminate true corneal change from measurement imprecision in keratoconus (KC). Thirty patients with KC and 30 healthy controls were included. Coefficients of repeatability and limits of agreement (LOA) were compared using multiple measurements for inter-observer and inter-device agreement with the Pentacam HR, Orbscan IIz, and Tomey Casia SS-1000. Correlation of repeated measurements was evaluated using a linear mixed effect model (also called random effect model). A formula was derived for the theoretical expected change in precision and compared with measured change. Correlation between measurements from the same eye was small (R = 0.13). The 99.73% LOA (3 SD) of the mean of three measurements, provided better precision than 95% LOA (2 SD) of single cut-off values as expected from statistical theory for uncorrelated measurements for evidence of a significant change in corneal shape in patients with keratoconus. This enabled the determination of cut-off values for the detection of true change in corneal shape. The mean of three repeated measurements will provide better precision when there is minimal correlation. Three (rather than two) standard deviations provides a precise estimate of the LOA within or between observers and can be used as a reliable measure for identifying stage-independent corneal shape changes (progression) in keratoconus
Comparative effect of interactive mobiles (clickers) and communicative approach on the learning outcomes of the educationally disadvantaged Nigerian pupils in ESL classrooms
Effective teaching that promotes learners’ active engagement and the development of
communicative proficiency has been a challenge to teachers of English as a second
language (ESL). Previous research on second language (L2) teaching has shown that
L2 learners improve better in communicative skills when they are actively engaged,
participate in communicative tasks that facilitate interaction and are provided with the
opportunity to use the target language in the classroom. This study focuses on
improving ESL learners’ learning outcomes in remotely-located primary schools in
Nigeria.
The study aimed to test whether the introduction of Personal Response System (PRS)
and communicative approach can improve pupils’ English-language communicative
competences and their attitudes towards English learning. Specifically, this study
examined the extent to which significant differences exist in pupils’ communicative
competence performance scores and learning gains based on teachers’ use of a
communicative approach, PRS and lecture methods in the ESL classroom.
Furthermore, the research also attempted to find out whether pupils’ attitudes towards
the learning of English would significantly differ based on teaching strategy. Attitudes
of pupils and teachers towards the interventions were also investigated.
A pre-test and post-test non-randomised control group design was adopted in this study.
Some qualitative data were also collected to augment the quantitative main data. Ninety
nine pupils from three intact classes in different schools in Ijebu-North local
government, Ogun-State, Nigeria were assigned to two experimental groups and one
control group. In addition to the traditional use of textbooks, one of the experimental
groups was taught using communicative activities, while the second experimental
group experienced communicative tasks blended with the use of a personal response
system. The control group received the conventional classroom instruction (lecture
method), including the use of the English language textbook. In order to provide
answers to the research questions and the hypothesis of this study, English Language
Listening Tests and English Language Speaking Tests, Pupils’ Attitude to English
Language Lesson Questionnaire, Pupils’ Attitude to Clickers’ Questionnaire and
Pupils’ Attitude to Communicative Approach Questionnaire were administered at the
pre-and post-test stages of the research. These instruments were also complemented
with data from classroom observation, video recording of the instructional process, and
audio-recorded interviews with the teachers and selected pupils in the experimental
groups.
The results indicate that the two experimental groups showed greater
improvement in communicative competence than did the control group; but the PRS
group improved more than the communicative approach group both in listening and
speaking skills development. Moreover, pupils’ learning gains were statistically
different, with the PRS group having the highest gain scores above the communicative
approach group, while the control group did not experience increased learning gains.
The results also reveal pupils’ mixed-reactions with respect to their attitudes toward the
English language lesson and the interventions. Teachers’ attitudes toward the
interventions were in the positive direction
Effects of Glyphosate and its Formulation, Roundup, on Reproduction in Zebrafish (Danio rerio)
This is an open access article that is freely available in ORE or from the publisher's web site. Please cite the published version.Copyright © 2014 American Chemical SocietyRoundup and its active ingredient glyphosate are among the most widely used herbicides worldwide and may contaminate surface waters. Research suggests both Roundup and glyphosate induce oxidative stress in fish and may also cause reproductive toxicity in mammalian systems. We aimed to investigate the reproductive effects of Roundup and glyphosate in fish and the potential associated mechanisms of toxicity. To do this, we conducted a 21-day exposure of breeding zebrafish (Danio rerio) to 0.01, 0.5, and 10 mg/L (glyphosate acid equivalent) Roundup and 10 mg/L glyphosate. 10 mg/L glyphosate reduced egg production but not fertilization rate in breeding colonies. Both 10 mg/L Roundup and glyphosate increased early stage embryo mortalities and premature hatching. However, exposure during embryogenesis alone did not increase embryo mortality, suggesting that this effect was caused primarily by exposure during gametogenesis. Transcript profiling of the gonads revealed 10 mg/L Roundup and glyphosate induced changes in the expression of cyp19a1 and esr1 in the ovary and hsd3b2, cat, and sod1 in the testis. Our results demonstrate that these chemicals cause reproductive toxicity in zebrafish, although only at high concentrations unlikely to occur in the environment, and likely mechanisms of toxicity include disruption of the steroidogenic biosynthesis pathway and oxidative stress.Natural Environment Research Counci
cGMP-Dependent Protein Kinase Type I Is Implicated in the Regulation of the Timing and Quality of Sleep and Wakefulness
Many effects of nitric oxide (NO) are mediated by the activation of guanylyl cyclases and subsequent production of the second messenger cyclic guanosine-3′,5′-monophosphate (cGMP). cGMP activates cGMP-dependent protein kinases (PRKGs), which can therefore be considered downstream effectors of NO signaling. Since NO is thought to be involved in the regulation of both sleep and circadian rhythms, we analyzed these two processes in mice deficient for cGMP-dependent protein kinase type I (PRKG1) in the brain. Prkg1 mutant mice showed a strikingly altered distribution of sleep and wakefulness over the 24 hours of a day as well as reductions in rapid-eye-movement sleep (REMS) duration and in non-REM sleep (NREMS) consolidation, and their ability to sustain waking episodes was compromised. Furthermore, they displayed a drastic decrease in electroencephalogram (EEG) power in the delta frequency range (1–4 Hz) under baseline conditions, which could be normalized after sleep deprivation. In line with the re-distribution of sleep and wakefulness, the analysis of wheel-running and drinking activity revealed more rest bouts during the activity phase and a higher percentage of daytime activity in mutant animals. No changes were observed in internal period length and phase-shifting properties of the circadian clock while chi-squared periodogram amplitude was significantly reduced, hinting at a less robust oscillator. These results indicate that PRKG1 might be involved in the stabilization and output strength of the circadian oscillator in mice. Moreover, PRKG1 deficiency results in an aberrant pattern, and consequently a reduced quality, of sleep and wakefulness, possibly due to a decreased wake-promoting output of the circadian system impinging upon sleep
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