1,439 research outputs found
MITOCHONDRIAL DNA POLYMORPHISMS AND FERTILITY IN BEEF CATTLE
Two regions of mitochondrial DNA, D-loop and ND-5 were characterized
using polymerase chain reaction – restriction fragment length polymorphism
(PCR-RFLP) involving 422 beef cattle of Hereford and composite breeds from
Wokalup’s research station. ANOVA models (model I, II) were used to estimate
associations between molecular haplotypes and quantitative traits. The
phenotypic data used were records on calving rate, defined as the mean number
of live calves born over four years, while the genotypic data used were the result
of PCR-RFLP analysis in both regions of mitochondrial DNA using 7 restriction
enzymes. The results of the present study have provided evidence that
mitochondrial polymorphisms in the D-loop and ND-5 regions are associated
significantly with fertility. This is the first report of a correlation between
mitochondrial polymorphism in D-loop and ND-5 on fertility in beef cattle.
Key words: PCR-RFLP, bovine mitochondrial DNA, D-loop, ND-5
Low-cost, precision, self-alignment technique for coupling laser and photodiode arrays to polymer waveguide arrays on multilayer PCBs
The first, to our knowledge, passive, precision, self-alignment technique for direct coupling of vertical cavity surface emitting laser (VCSEL) and photodiode (PD) arrays to an array of polymer buried channel waveguides on a rigid printed circuit board (PCB) is reported. It gives insertion losses as good as the best achieved previously, to within experimental measurement accuracy, but without the need for costly active alignment nor waveguide facet polishing and so is a major step towards a commercially realizable low cost connector. Such an optical connector with four duplex channels each operating at 10 Gb/s (80 Gb/s aggregate) was designed, constructed, and its alignment precision assessed. The alignment technique is applicable to polymer waveguide interconnections on both rigid and flexible multilayer printed circuit boards (PCBs). The dependence of optical coupling loss on mis-alignments in x, y and z of the VCSEL and PD arrays allows the precision of alignment to be assessed and its reproducibility on multiple mating cycles of the connector is reported. The first recorded measurements of crosstalk between waveguides when the connector is misaligned are reported. Lateral misalignments of the connector to within its tolerance are shown to have no effect on the signal to crosstalk ratio (SCR), to within experimental measurement accuracy. The insertion loss repeatability is similar to that of single mode fiber mechanically transferable (MT) connectors
Decentering mediates the relationship between vmPFC activation during a stressor and positive emotion during stress recovery
The stress response has profound implications on health and behaviour and stress is considered a risk factor for the development of psychopathologies including depression. The neural mechanisms supporting successful stress recovery are not fully understood, however a novel study by Yang et al. demonstrates that vmPFC activation during a stressor is related to improved stress recovery, and that decentering is able to mediate this relationship, suggesting a role during stress recovery. It was also revealed that vmPFC activation at different time points during the stressor predicts altering aspects of stress recovery, an observation that was only possible due to the adoption of change-point analysis
The neural mechanisms able to predict future emotion regulation decisions
Emotion regulation is crucial in maintaining healthy psychological wellbeing, and its dysregulation is often linked to a range of neuropsychiatric disorders including depression. The neurobiological underpinnings of cognitive reappraisal, an emotion regulation strategy, have been shown to include the amygdala and regions of the prefrontal cortex. A novel study by Doré, Weber, and Ochsner (2017) has demonstrated that neural activity in these regions during uninstructed visualization of affective stimuli can successfully predict which individuals are more likely to subsequently employ emotion regulation, and under what circumstances
FirstLight: Pluggable Optical Interconnect Technologies for Polymeric Electro-Optical Printed Circuit Boards in Data Centers
The protocol data rate governing data storage devices will increase to over 12 Gb/s by 2013 thereby imposing unmanageable cost and performance burdens on future digital data storage systems. The resulting performance bottleneck can be substantially reduced by conveying high-speed data optically instead of electronically. A novel active pluggable 82.5 Gb/s aggregate bit rate optical connector technology, the design and fabrication of a compact electro-optical printed circuit board to meet exacting specifications, and a method for low cost, high precision, passive optical assembly are presented. A demonstration platform was constructed to assess the viability of embedded electro-optical midplane technology in such systems including the first ever demonstration of a pluggable active optical waveguide printed circuit board connector. High-speed optical data transfer at 10.3125 Gb/s was demonstrated through a complex polymer waveguide interconnect layer embedded into a 262 mm × 240 mm × 4.3 mm electro-optical midplane. Bit error rates of less than 10-12 and optical losses as low as 6 dB were demonstrated through nine multimode polymer wave guides with an aggregate data bandwidth of 92.8125 Gb/s
Emotional real-world scenes impact visual search
Research shows that emotional stimuli can capture attention, and this can benefit or impair performance, depending on the characteristics of a task. Additionally, whilst some findings show that attention expands under positive conditions, others show that emotion has no influence on the broadening of attention. The current study investigated whether emotional real-world scenes influence attention in a visual search task. Participants were asked to identify a target letter embedded in the centre or periphery of emotional images. Identification accuracy was lower in positive images compared to neutral images, and
response times were slower in negative images. This suggests that real-world emotional stimuli have a distracting effect on visual attention and search. There was no evidence that emotional images influenced the spatial spread of attention. Instead, it is suggested that findings may provide support for the argument that positive emotion encourages a global processing style and negative emotion promotes local processing
Psychophysiological indices of cognitive style : a triangulated study incorporating neuroimaging, eye-tracking, psychometric and behavioral measures
Employing a triangulated design to explore psychophysiological indices of cognitive style, the study investigated the validity of the intuition-analysis dimension of cognitive style and its associated construct measure, the Cognitive Style Index (CSI). Participants completed a comparative visual search (CVS) task whilst changes in hemodynamic concentrations in the prefrontal cortex (PFC) were monitored using functional near-infrared spectroscopy and eye movements were recorded together with task performance measures of response time and accuracy. Results revealed significant style-related differences in response time and number of saccades. Analysts were characterized by fewer saccadic eye movements and quicker response times - but with comparable accuracy scores - compared to intuitives, suggesting a more efficient visual search strategy and decision-making style on the experimental task. No style-related differences in neural activation were found, suggesting that differences were not mediated by style-specific variations in brain activation or hemispheric lateralization. Task-evoked neural activation - compared with baseline resting state - represented the value of PFC-based neural activation measures in studies of cognitive processing. Findings demonstrated style-related differences supporting the intuition-analysis dimension of cognitive style and the validity of the CSI as a psychometric measure of style. The potential value of valid psychometric measures of cognitive style in applied areas is highlighted.
Key words: cognitive style, information processing, Cognitive Style Index, functional near-infrared 21 spectroscopy, eye-tracking, neuroimaging, Bayesian statistic
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