2,416 research outputs found
Development of white matter microstructure and executive functions during childhood and adolescence: a review of diffusion MRI studies
Diffusion magnetic resonance imaging (dMRI) provides indirect measures of white matter microstructure that can be used to make inferences about structural connectivity within the brain. Over the last decade, a growing literature of cross-sectional and longitudinal studies have documented relationships between dMRI indices and cognitive development. In this review, we provide a brief overview of dMRI methods and how they can be used to study white matter and connectivity and review the extant literature examining the links between dMRI indices and executive functions during development. We explore the links between white matter microstructure and specific executive functions: inhibition, working memory and cognitive shifting, as well as performance on complex executive function tasks. Concordance in findings across studies are highlighted, and potential explanations for discrepancies between results, together with challenges with using dMRI in child and adolescent populations, are discussed. Finally, we explore future directions that are necessary to better understand the links between child and adolescent development of structural connectivity of the brain and executive functions
New Russulaceae species in south-east Queensland
Russula species are ectomycorrhizal basidiomycetes common throughout Australian woodlands. Molecular and morphological examination of Russula specimens from various sites in South-east Queensland has uncovered a number of phylogenetically diverse and potentially undescribed specimens. At this stage, most of these remain as individual specimens. However, several specimens have been grouped into project species. In this presentation, two potentially new species of Russula will be described. Both species are widespread on red to black clay soils in the Toowoomba region and appear to be phylogenetically related to each other. Project species 1 has a white stipe which developed a pink flush after collection and red to pink centrally depressed cap with white gills. The spores of this species were subglobose, white and ornamented with amyloid warts connected in short chains. The second species, project species 3, is macroscopically similar, differing with its larger size, purple-pink cap colour, and rougher cap texture. Its spores are globose to subglobose, white and ornamented with small amyloid warts connected in short chains. Continued molecular and morphological studies of the Russula species of South-east Queensland may uncover more novel Australian species
What Makes You Proactive Can Burn You Out: The Downside of Proactive Skill Building Motivated by Financial Precarity and Fear
Proactivity at work is generally assumed to be preceded by positive motivational states with positive outcomes for employees. However, recent perspectives suggest downsides to proactive behavior, including that it can be driven by negative emotions or experienced as depleting for employees. Bringing these previously disconnected ideas together, we utilize cognitive–motivational–relational and self-determination theories to holistically examine the negative antecedents of proactivity and its outcomes. We argue that employees, particularly those with high impression management motives, experience burnout when financial precarity and fear drive them to proactively learn new skills. We test and show support for these hypotheses in a four-wave study of 1, 315 university employees during the beginning of the COVID-19 pandemic, an external event that threatened employees’ financial security. Theoretically, our findings broaden our understanding of the antecedents and consequences of proactivity, while expanding the role of fear at work beyond “flight” responses to include motivating protective effort. Practically, our findings help to understand both how employees proactively develop their skills in light of financial precarity and how these proactive efforts are experienced as depleting
Feed size and texture influence propionic and butyric acid concentrations and Escherichia coli populations in the pig gastrointestinal tract
Natural approaches are now being considered to replace antimicrobials to reduce the risk of antimicrobial resistance development. This has put the new emphasis on using diet to control bacterial infections in pigs, some of which having recently demonstrated a zoonotic disease potential
Biodegradation of endocrine disrupting compounds by bacterial communities from contaminated environments in Macau
info:eu-repo/semantics/publishedVersio
The TPR-containing domain within Est1 homologs exhibits species-specific roles in telomerase interaction and telomere length homeostasis
<p>Abstract</p> <p>Background</p> <p>The first telomerase-associated protein (Est1) was isolated in yeast due to its essential role in telomere maintenance. The human counterparts EST1A, EST1B, and EST1C perform diverse functions in nonsense-mediated mRNA decay (NMD), telomere length homeostasis, and telomere transcription. Although Est1 and EST1A/B interact with the catalytic subunit of yeast and human telomerase (Est2 and TERT, respectively), the molecular determinants of these interactions have not been elaborated fully.</p> <p>Results</p> <p>To investigate the functional conservation of the EST1 protein family, we performed protein-protein interaction mapping and structure-function analysis. The domain in hEST1A most conserved between species, containing a TPR (tricotetrapeptide repeat), was sufficient for interaction of hEST1A with multiple fragments of hTERT including the N-terminus. Two mutations within the hTERT N-terminus that perturb <it>in vivo </it>function (NAAIRS<sub>92</sub>, NAAIRS<sub>122</sub>) did not affect this protein interaction. ScEst1 hybrids containing the TPR of hEST1A, hEST1B, or hEST1C were expressed in yeast strains lacking <it>EST1</it>, yet they failed to complement senescence. Point mutations within and outside the cognate ScEst1 TPR, chosen to disrupt a putative protein interaction surface, resulted in telomere lengthening or shortening without affecting recruitment to telomeres.</p> <p>Conclusions</p> <p>These results identify a domain encompassing the TPR of hEST1A as an hTERT interaction module. The TPR of <it>S. cerevisiae </it>Est1 is required for telomerase-mediated telomere length maintenance in a manner that appears separable from telomere recruitment. Discrete residues in or adjacent to the TPR of Est1 also regulate telomere length homeostasis.</p
Impact of mash feeding versus pellets on propionic/butyric acid levels and on total Escherichia coli load in the gastrointestinal tract of growing pigs
Feed characteristics may influence
the bacterial community composition and metabolic
activities in the pig gastrointestinal tract, known to be
associated with positive effects on the gut. Use of mash
feed is associated with reduced Salmonella excretion,
but little is known of its effect on the Escherichia coli
population or of the mechanism of action. Our objectives
were to assess the effect of feed texture combined
with feed particle size on VFA profiles and levels,
total E. coli count, and the presence of genes encoding
virulence factors of pathogenic E. coli strains in the
digestive tract along with their impact on pig performance
of fattening pigs. Pigs (n = 840) on a commercial
farm received mash or pellet diets of different particle
sizes during the fattening period. Caecal and colon contents
from 164 pigs were sampled at the slaughterhouse
for enumeration of E. coli by quantitative PCR (qPCR)
and for VFA quantification by capillary gas chromatography.
The yccT gene was used to enumerate total E.
coli. Improved pig performances associated with pellet
texture and a 500-μm size were observed. Caecal (P =
0.02) and colon (P < 0.01) propionic acid concentrations
were lower for pigs receiving pellet rather than
mash feed. Similarly, caecal (P = 0.01) and colon (P <
0.001) butyric acid concentrations were also lower for
pigs receiving pellet rather than mash feed, as determined
by capillary gas chromatography. Moreover,
caecal (P = 0.03) and colon (P < 0.001) butyric acid
concentrations were higher for pigs receiving a feed
with a 1,250-μm particle size rather than a 500-μm
particle size. On the other hand, total caecal and colon
E. coli levels were higher for pigs receiving pellet feed
than for those receiving mash feed. For total E. coli
enumeration, caecal (P < 0.01) and colon (P < 0.01)
yccT gene copies were higher for pigs receiving pellet
rather than mash feed. No effect of particle size on
fatty acid concentrations or on E. coli numbers was
observed. Virulence gene quantification revealed no
trend. Taken together, results showed that mash feed
is associated with lower growth performance but with
favorable intestinal changes linked to VFA levels and E.
coli reduction in the intestine
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