Demographic characteristics of exploited tropical lutjanids: a comparative analysis

Demographic parameters from seven exploited coral reef lutjanid species were compared as a case study of the implications of intrafamily variation in life histories for multispecies harvest management. Modal lengths varied by 4 cm among four species (Lutjanus fulviflamma, L. vitta, L. carponotatus, L. adetii), which were at least 6 cm smaller than the modal lengths of the largest species (L. gibbus, Symphorus nematophorus, Aprion virescens). Modal ages, indicating ages of full selection to fishing gear, were 10 years or less for all species, but maximum ages ranged from 12 (L. gibbus) to 36 years (S. nematophorus). Each species had a unique growth pattern, with differences in length-at-age and mean asymptotic fork length (L∞), but smaller species generally grew fast during the first 1–2 years of life and larger species grew more slowly over a longer period. Total mortality rates varied among species; L. gibbus had the highest mortality and L. fulviflamma, the lowest mortality. The variability in life history strategies of these tropical lutjanids makes generalizations about lutjanid life histories difficult, but the fact that all seven had characteristics that would make them particularly vulnerable to fishing indicates that harvest of tropical lutjanids should be managed with caution

Spatial and fishing effects on sampling gear biases in a tropical reef line fishery

Biased estimates of population parameters for harvested stocks can have severe implications for fishery management strategy choices. Hook-and-line fishing gear is size-selective and therefore collects biased samples from wild populations. Such biases may also vary in space and time. To assess this assertion, we compared line- and spear-caught samples of the main target species of an Australian hook-and-line fishery to quantify relative bias in size and age structure estimates. We also assessed the consistency of biases among four fishery regions and between two management zones – areas open and closed to fishing. Fish less than 310 mm and younger than 4 years comprised a larger proportion of the speared than the line samples regardless of region or management zone. Conversely, hook-and-line sampled more fish in larger size classes (>370 mm) and older age classes (≥6 years) relative to spear fishing. These biases were qualitatively, but not quantitatively, consistent in all regions and management zones. This variation in sampling resulted in different inferences about regional and zone-related patterns in population size and age structure. We recommend careful consideration of sampling bias when drawing conclusions about regional and management zone effects on fish populations

Diversity and occurrence of siphonophores in Irish coastal waters

Siphonophores are at times amongst the most abundant invertebrate zooplankton predators in the oceans. Historically, siphonophores have been under-sampled and of the studies conducted there has been a bias towards oceanic oligotrophic waters where they are considered to be more important. In temperate coastal regions, comparatively less is known about the diversity and abundance of siphonophores, where periodic blooms can restructure the plankton communities and have been correlated with high mortalities in the salmon aquaculture industry. To address this lack of knowledge, plankton samples were collected during two periods (March 2009-March 2011 and April 2014-November 2015) from a coastal embayment in the southwest of Ireland. In total, three siphonophore species were found, the calycophoran Muggiaea atlantica, and the physonects, Nanomia bijuga and Agalma elegans. Muggiaea atlantica was the most abundant species (250 colonies m−3), with densities an order of magnitude higher than either physonect. Muggiaea atlantica displayed a distinct seasonality, whereas the physonect species were sporadic in occurrence. Comparing siphonophores in Bantry Bay and the Western English Channel (Plymouth Marine Laboratory's L4 station) indicates both regions share a similar pattern of inter-annual occurrence and provides novel information on the seasonality and occurrence of siphonophores in Irish coastal waters

Evaluation of objective and perceived mental fatigability in older adults with vascular risk

Objectives: Mental fatigability refers to the failure to sustain participation in tasks requiring mental effort. Older adults with vascular risk are at particular risk for experiencing mental fatigability. The present study (1) tested a new way of measuring objective mental fatigability by examining its association with perceived mental fatigability; and (2) identified associated psychological, physiological, and situational predictors. Methods: A cross-sectional study was conducted with 49 community-dwelling participants aged 75. + years with vascular risk. A 20-minute fatigability-manipulation task was used to induce mental fatigability and develop objective and perceived mental fatigability measures. Objective fatigability was calculated by the change of reaction time over the course of the task. Perceived fatigability was calculated by the change of fatigue self-reported before and after the task. A set of potential psychological, physiological, and situational predictors were measured. Results: There was a significant increase in reaction time and self-reported fatigue to the fatigability manipulation task, indicating occurrence of objective and perceived mental fatigability. Reaction time and self-reported fatigue were moderately, but significantly correlated. Higher levels of executive control and having a history of more frequently engaging in mental activities were associated with lower objective mental fatigability. None of the examined factors were associated with perceived mental fatigability. Conclusion: Objective and perceived mental fatigability were sensitive to our fatigability-manipulation task. While these two measures were correlated, they were not associated with the same factors. These findings need to be validated in studies with a more heterogeneous sample and a greater variety of fatigability-manipulation tasks

Tackling the jelly web: Trophic ecology of gelatinous zooplankton in oceanic food webs of the eastern tropical Atlantic assessed by stable isotope analysis

Gelatinous zooplankton can be present in high biomass and taxonomic diversity in planktonic oceanic food webs, yet the trophic structuring and importance of this “jelly web” remain incompletely understood. To address this knowledge gap, we provide a holistic trophic characterization of a jelly web in the eastern tropical Atlantic, based on δ13C and δ15N stable isotope analysis of a unique gelatinous zooplankton sample set. The jelly web covered most of the isotopic niche space of the entire planktonic oceanic food web, spanning > 3 trophic levels, ranging from herbivores (e.g., pyrosomes) to higher predators (e.g., ctenophores), highlighting the diverse functional roles and broad possible food web relevance of gelatinous zooplankton. Among gelatinous zooplankton taxa, comparisons of isotopic niches pointed to the presence of differentiation and resource partitioning, but also highlighted the potential for competition, e.g., between hydromedusae and siphonophores. Significant differences in spatial (seamount vs. open ocean) and depth‐resolved patterns (0–400 m vs. 400–1000 m) pointed to additional complexity, and raise questions about the extent of connectivity between locations and differential patterns in vertical coupling between gelatinous zooplankton groups. Added complexity also resulted from inconsistent patterns in trophic ontogenetic shifts among groups. We conclude that the broad trophic niche covered by the jelly web, patterns in niche differentiation within this web, and substantial complexity at the spatial, depth, and taxon level call for a more careful consideration of gelatinous zooplankton in oceanic food web models. In light of climate change and fishing pressure, the data presented here also provide a valuable baseline against which to measure future trophic observations of gelatinous zooplankton communities in the eastern tropical Atlantic

Sex‐specific associations between AD genotype and the microbiome of human amyloid beta knock‐in (hAβ‐KI) mice

IntroductionEmerging evidence links changes in the gut microbiome to late-onset Alzheimer's disease (LOAD), necessitating examination of AD mouse models with consideration of the microbiome.MethodsWe used shotgun metagenomics and untargeted metabolomics to study the human amyloid beta knock-in (hAβ-KI) murine model for LOAD compared to both wild-type (WT) mice and a model for early-onset AD (3xTg-AD).ResultsEighteen-month female (but not male) hAβ-KI microbiomes were distinct from WT microbiomes, with AD genotype accounting for 18% of the variance by permutational multivariate analysis of variance (PERMANOVA). Metabolomic diversity differences were observed in females, however no individual metabolites were differentially abundant. hAβ-KI mice microbiomes were distinguishable from 3xTg-AD animals (81% accuracy by random forest modeling), with separation primarily driven by Romboutsia ilealis and Turicibacter species. Microbiomes were highly cage specific, with cage assignment accounting for more than 40% of the PERMANOVA variance between the groups.DiscussionThese findings highlight a sex-dependent variation in the microbiomes of hAβ-KI mice and underscore the importance of considering the microbiome when designing studies that use murine models for AD.HighlightsMicrobial diversity and the abundance of several species differed in human amyloid beta knock-in (hAβ-KI) females but not males. Correlations to Alzheimer's disease (AD) genotype were stronger for the microbiome than the metabolome. Microbiomes from hAβ-KI mice were distinct from 3xTg-AD mice. Cage effects accounted for most of the variance in the microbiome and metabolome

Fatigability disrupts cognitive processes' regulation of inflammatory reactivity in old age

Objective High fatigability, a dysfunctional adaption to fatigue, may lead to difficulties performing otherwise regularly encountered cognitive activities and may be related to pro-inflammatory reactivity. The purpose of the study was to investigate the effect of fatigability on cognitive processes and inflammatory response after an acute cognitive stress task in older adults. Methods In an observational stress reactivity study conducted in a light-and temperature-controlled laboratory, we measured IL-6, self-reported acute fatigue, and frontally oriented cognitive processes in 55 community-dwelling individuals aged 75 years or older as part of a demanding set of cognitive tasks intended to induce stress. Results Subjects were classified into groups of low and high fatigability based on cluster analysis of their self-report acute fatigue before and after the cognitive tasks. The two clusters were comparable on levels of baseline IL-6 and cognitive processes; however, the high fatigability cluster had significantly higher levels of IL-6 response than the low fatigability cluster. After controlling for multiple covariates, fatigability moderated the relationship between speed of processing and IL-6 reactivity. Further exploratory analyses indicated significant adverse associations between speed of processing and attention and IL-6 reactivity in the group with low but not high fatigability. Conclusion Although observational, these data are consistent with the notion that pro-inflammatory states in older adults might be reduced by improvements in cognitive processes. Because fatigability was associated with increased acute inflammatory response and disrupted the normal stress regulation provided by the cognitive processes, future randomized studies might examine whether fatigability alleviation reduces IL-6

A Systematic Literature Review of Students as Partners in Higher Education

“Students as Partners” (SaP) in higher education re-envisions students and staff as active collaborators in teaching and learning. Understanding what research on partnership communicates across the literature is timely and relevant as more staff and students come to embrace SaP. Through a systematic literature review of empirical research, we explored the question: How are SaP practices in higher education presented in the academic literature? Trends across results provide insights into four themes: the importance of reciprocity in partnership; the need to make space in the literature for sharing the (equal) realities of partnership; a focus on partnership activities that are small scale, at the undergraduate level, extracurricular, and focused on teaching and learning enhancement; and the need to move toward inclusive, partnered learning communities in higher education. We highlight nine implications for future research and practice.</jats:p

Phospholipid oxidation and carotenoid supplementation in Alzheimer’s disease patients

Alzheimer's disease (AD) is a progressive, neurodegenerative disease, characterised by decline of memory, cognitive function and changes in behaviour. Generic markers of lipid peroxidation are increased in AD, therefore reactive oxygen species have been suggested to be involved in the aetiology of cognitive decline. Carotenoids are depleted in AD serum, therefore we have compared serum lipid oxidation between AD and age-matched control subjects before and after carotenoid supplementation. The novel oxidised phospholipid biomarker 1-palmitoyl-2-(5'-oxo-valeroyl)-sn-glycero-3-phosphocholine (POVPC) was analysed using electrospray ionization tandem mass spectrometry (MS) with multiple reaction monitoring (MRM), 8-isoprostane (IsoP) was measured by ELISA and ferric reducing antioxidant potential (FRAP) was measured by a colorimetric assay. AD patients (n=21) and healthy age-matched control subjects (n=16) were supplemented with either Macushield™ (10 mg meso-zeaxanthin, 10 mg lutein, 2 mg zeaxanthin) or placebo (sunflower oil) for six months. The MRM-MS method determined serum POVPC sensitively (from 10 µl serum) and reproducibly (CV=7.9%). At baseline, AD subjects had higher serum POVPC compared to age-matched controls, (p=0.017) and cognitive function was correlated inversely with POVPC (r=−0.37; p=0.04). After six months of carotenoid intervention, serum POVPC was not different in AD patients compared to healthy controls. However, POVPC was significantly higher in control subjects after six months of carotenoid intervention compared to their baseline (p=0.03). Serum IsoP concentration was unrelated to disease or supplementation. Serum FRAP was significantly lower in AD than healthy controls but was unchanged by carotenoid intervention (p=0.003). In conclusion, serum POVPC is higher in AD patients compared to control subjects, is not reduced by carotenoid supplementation and correlates with cognitive function