How modularity and heterotrophy complicate the understanding of the causes of thermal performance curves: the case of feeding rate in a filter-feeding animal.

Warming global temperatures have consequences for biological rates. Feeding rates reflect the intake of energy that fuels survival, growth and reproduction. However, temperature can also affect food abundance and quality, as well as feeding behavior, which all affect feeding rate, making it challenging to understand the pathways by which temperature affects the intake of energy. Therefore, we experimentally assessed how clearance rate varied across a thermal gradient in a filter-feeding colonial marine invertebrate (the bryozoan Bugula neritina). We also assessed how temperature affects phytoplankton as a food source, and zooid states within a colony that affect energy budgets and feeding behavior. Clearance rate increased linearly from 18°C to 32°C, a temperature range that the population experiences most of the year. However, temperature increased algal cell size, and decreased the proportion of feeding zooids, suggesting indirect effects of temperature on clearance rates. Temperature increased polypide regression, possibly as a stress response because satiation occurred quicker, or because phytoplankton quality declined. Temperature had a greater effect on clearance rate per feeding zooid than it did per total zooids. Together, these results suggest that the effect of temperature on clearance rate at the colony level is not just the outcome of individual zooids feeding more in direct response to temperature but also emerges from temperature increasing polypide regression and the remaining zooids increasing their feeding rates in response. Our study highlights some of the challenges for understanding why temperature affects feeding rates, especially for understudied, yet ecologically important, marine colonial organisms.

The potential of repetitive transcranial magnetic stimulation for addressing sleep difficulties in children with autism - A brief communication.

Sleep difficulties can co-occur with autistic traits and have been frequently reported in children diagnosed with autism. Thus, sleep difficulties may impact neural development, cognition, and behavioural functioning in children with autism. Interventions, such as repetitive transcranial magnetic stimulation (rTMS), that target aberrant neural structures underpinning autistic traits and sleep difficulties in children could have beneficial effects. The rTMS effects on the pathophysiological pathways hypothesised to underpin autism and sleep difficulties are well-established in the literature; however, clinical evidence of its potential to improve sleep difficulties in children with autism is limited. While the preliminary data is promising, further robust rTMS studies are warranted to encourage its use in clinical practices.

Larval and Adult Traits Coevolve in Response to Asymmetric Coastal Currents to Shape Marine Dispersal Kernels.

AbstractDispersal emerges as an outcome of organismal traits and external forcings. However, it remains unclear how the emergent dispersal kernel evolves as a by-product of selection on the underlying traits. This question is particularly compelling in coastal marine systems, where dispersal is tied to development and reproduction and where directional currents bias larval dispersal downstream, causing selection for retention. We modeled the dynamics of a metapopulation along a finite coastline using an integral projection model and adaptive dynamics to understand how asymmetric coastal currents influence the evolution of larval (pelagic larval duration) and adult (spawning frequency) life history traits, which indirectly shape the evolution of marine dispersal kernels. Selection induced by alongshore currents favors the release of larvae over multiple time periods, allowing long pelagic larval durations and long-distance dispersal to be maintained in marine life cycles in situations where they were previously predicted to be selected against. Two evolutionarily stable strategies emerged: one with a long pelagic larval duration and many spawning events, resulting in a dispersal kernel with a larger mean and variance, and another with a short pelagic larval duration and few spawning events, resulting in a dispersal kernel with a smaller mean and variance. Our theory shows how coastal ocean flows are important agents of selection that can generate multiple, often co-occurring evolutionary outcomes for marine life history traits that affect dispersal.

Early post-settlement events, rather than settlement, drive recruitment and coral recovery at Moorea, French Polynesia.

Understanding population dynamics is a long-standing objective of ecology, but the need for progress in this area has become urgent. For coral reefs, achieving this objective is impeded by a lack of information on settlement versus post-settlement events in determining recruitment and population size. Declines in coral abundance are often inferred to be associated with reduced densities of recruits, which could arise from mechanisms occurring at larval settlement, or throughout post-settlement stages. This study uses annual measurements from 2008 to 2021 of coral cover, the density of coral settlers (S), the density of small corals (SC), and environmental conditions, to evaluate the roles of settlement versus post-settlement events in determining rates of coral recruitment and changes in coral cover at Moorea, French Polynesia. Coral cover, S, SC, and the SC:S ratio (a proxy for post-settlement success), and environmental conditions, were used in generalized additive models (GAMs) to show that: (a) coral cover was more strongly related to SC and SC:S than S, and (b) SC:S was highest when preceded by cool seawater, low concentrations of Chlorophyll a, and low flow speeds, and S showed evidence of declining with elevated temperature. Together, these results suggest that changes in coral cover in Moorea are more strongly influenced by post-settlement events than settlement. The key to understanding coral community resilience may lie in elucidating the factors attenuating the bottleneck between settlers and small corals.

Longitudinal change in sleep, functional, and behavioural characteristics in a cohort of children with Down syndrome.

This paper describes the longitudinal change in sleep, functional, and behavioural characteristics in a cohort of children with Down syndrome, including the effect of sleep interventions in a subset. A prospective longitudinal cohort study was undertaken in children with Down syndrome aged 3-16 years comparing (1) children referred to a tertiary sleep medicine clinic who received sleep hygiene advice and an additional sleep treatment (DSref_I) with (2) children attending the same clinic who only received sleep hygiene advice (DSref_N) and (3) children recruited from the community who, were not receiving any treatment (DScomm). Data collected included demographic and medical history information, Child Sleep Habits Questionnaire-Abbreviated (CSHQ-A), Life-Habits Questionnaire (Life-H) and Child Behaviour Checklist (CBCL) at baseline and then 6-monthly for a total of 18 months. Any sleep interventions during this time were recorded. A total of 57 children were included (DSref_I, n = 16; DSref_N, n = 25; DScomm, n = 16). At recruitment, the median CSHQ-A total score was high (>41) in all three subgroups, but highest in the DSref_I subgroup (median [interquartile range] Dsref_I score 58 [53-66] versus DSref_N score 49 [43-53], p = 0.019). Although improved, 80% of participants in the DSref_I subgroup still had a CSHQ-A total score >41 at the last assessment point. The median total Life-H and total CBCL scores were not significantly different between groups at baseline and there was no significant time, group, or interaction effect seen through the study. Over an 18-month period, sleep problems were seen to persist in children with Down syndrome. Treatment resulted in only modest improvements in sleep.

Hidden heatwaves and severe coral bleaching linked to mesoscale eddies and thermocline dynamics.

The severity of marine heatwaves (MHWs) that are increasingly impacting ocean ecosystems, including vulnerable coral reefs, has primarily been assessed using remotely sensed sea-surface temperatures (SSTs), without information relevant to heating across ecosystem depths. Here, using a rare combination of SST, high-resolution in-situ temperatures, and sea level anomalies observed over 15 years near Moorea, French Polynesia, we document subsurface MHWs that have been paradoxical in comparison to SST metrics and associated with unexpected coral bleaching across depths. Variations in the depth range and severity of MHWs was driven by mesoscale (10s to 100s of km) eddies that altered sea levels and thermocline depths and decreased (2007, 2017 and 2019) or increased (2012, 2015, 2016) internal-wave cooling. Pronounced eddy-induced reductions in internal waves during early 2019 contributed to a prolonged subsurface MHW and unexpectedly severe coral bleaching, with subsequent mortality offsetting almost a decade of coral recovery. Variability in mesoscale eddy fields, and thus thermocline depths, is expected to increase with climate change, which, along with strengthening and deepening stratification, could increase the occurrence of subsurface MHWs over ecosystems historically insulated from surface ocean heating by the cooling effects of internal waves.

Dispersal, kin aggregation, and the fitness consequences of not spreading sibling larvae.

Dispersal has far-reaching implications for individuals, populations, and communities, especially in sessile organisms. Escaping competition with conspecifics and with kin are theorized to be key factors leading to dispersal as an adaptation. However, manipulative approaches in systems in which adults are sessile but offspring have behaviors is required for a more complete understanding of how competition affects dispersal. Here, we integrate a series of experiments to study how dispersal affects the density and relatedness of neighbors, and how the density and relatedness of neighbors in turn affects fitness. In a marine bryozoan, we empirically estimated dispersal kernels and found that most larvae settled within ~1 m of the maternal colony, although some could potentially travel at least 10s of meters. Larvae neither actively preferred or avoided conspecifics or kin at settlement. We experimentally determined the effects of spreading sibling larvae by manipulating the density and relatedness of settlers and measuring components of fitness in the field. We found that settler density reduced maternal fitness when settler neighbors were siblings compared with when neighbors were unrelated or absent. Genetic markers also identified very few half sibs (and no full sibs) in adults from the natural population, and rarely close enough to directly interact. In this system, dispersal occurs over short distances (meters) yet, in contrast with expectations, there appears to be limited kinship between adult neighbors. Our results suggest that the limited dispersal increases early offspring mortality when siblings settle next to each other, rather than next to unrelated conspecifics, potentially reducing kinship in adult populations. High offspring production and multiple paternity could further dilute kinship at settlement and reduce selection for dispersal beyond the scale of 10s of meters.

Parents' Experiences of Having a Child with Down Syndrome and Sleep Difficulties.

OBJECTIVES: Sleep disorders are prevalent in children with Down Syndrome (DS). However, sleep treatment is not always readily accessed by this group. This study aims to understand families' experiences of having a child with DS and sleep difficulties, and in particular, their healthcare experiences, with the goal of informing practice improvements. METHODS: We conducted semi-structured interviews with 34 parents (fathers n = 4 and mothers n = 30) with open-ended questions about parents' experiences of sleep, family dynamics, and healthcare. We operationalized a reflexive Thematic Analysis. RESULTS: Parents normalized their experiences of having a child with DS and sleep problems. Parents acknowledged that sleep disruption has adverse and pervasive impacts on their wellbeing and family dynamics, but also found this difficult to identify as a health problem. They accepted sleep difficulties as a regular part of bringing up any child, particularly one with a disability. When they did seek treatment for their child's sleep difficulties, parents often reported encountering insensitive and inadequate care and described that, at times, healthcare professionals also normalized children's sleep difficulties, resulting in sub-optimal treatment. This included at times failure to refer to tertiary sleep medicine services when required. CONCLUSIONS: Parents' and healthcare professionals' normalization of sleeping difficulties denies that they are both deleterious and modifiable. Practice implications include raising healthcare professionals' awareness of the importance of proactively addressing sleep, with sensitivity to families' normalization strategies, recognizing that families may require prompting to report concerns.

Pocillopora tuahiniensis: a new species of scleractinian coral (Scleractinia, Pocilloporidae) from French Polynesia.

Pocillopora tuahiniensis sp. nov. is described based on mitochondrial and nuclear genomic data, algal symbiont genetic data, geographic isolation, and its distribution pattern within reefs that is distinct from other sympatric Pocillopora species (Johnston et al. 2022a, b). Mitochondrial and nuclear genomic data reveal that P. tuahiniensis sp. nov. is a unique species, sister to P. verrucosa, and in a clade different from that of P. meandrina (Johnston et al. 2022a). However, the gross in situ colony appearance of P. tuahiniensis sp. nov. cannot easily be differentiated from that of P. verrucosa or P. meandrina at Moorea. By sequencing the mtORF region, P. tuahiniensis sp. nov. can be easily distinguished from other Pocillopora species. Pocillopora tuahiniensis sp. nov. has so far been sampled in French Polynesia, Ducie Island, and Rapa Nui (Armstrong et al. 2023; Edmunds et al. 2016; Forsman et al. 2013; Glin et al. 2017; Mayfield et al. 2015; Oury et al. 2021; Voolstra et al. 2023). On the fore reefs of Moorea, P. tuahiniensis sp. nov. is very abundant 10 m and is one of the most common Pocillopora species at these depths (Johnston et al. 2022b). It can also be found at a much lower abundance at shallow depths on the fore reef and back reef lagoon. The holotype is deposited at the Smithsonian Institution as USNM-SI 1522390 and the mtORF Genbank accession number is OP418359.

Branching coral morphology affects physiological performance in the absence of colony integration.

For nearly 50 years, analyses of coral physiology have used small coral fragments (nubbins) to make inferences about larger colonies. However, scaling in corals shows that linear extrapolations from nubbins to whole colonies can be misleading, because polyps in nubbins are divorced of their morphologically complex and physiologically integrated corallum. We tested for the effects of integration among branches in determining size-dependent calcification of the coral Pocillopora spp. under elevated PCO2. Area-normalized net calcification was compared between branches (nubbins), aggregates of nubbins (complex morphologies without integration) and whole colonies (physiologically integrated) at 400 versus approximately 1000 µatm PCO2. Net calcification was unaffected by PCO2, but differed among colony types. Single nubbins grew faster than whole colonies, but when aggregated, nubbins changed calcification to match whole colonies even though they lacked integration among branches. Corallum morphology causes the phenotype of branching corals to differ from the summation of their branches.

Cophylogeny and specificity between cryptic coral species (Pocillopora spp.) at Mo'orea and their symbionts (Symbiodiniaceae).

The congruence between phylogenies of tightly associated groups of organisms (cophylogeny) reflects evolutionary links between ecologically important interactions. However, despite being a classic example of an obligate symbiosis, tests of cophylogeny between scleractinian corals and their photosynthetic algal symbionts have been hampered in the past because both corals and algae contain genetically unresolved and morphologically cryptic species. Here, we studied co-occurring, cryptic Pocillopora species from Mo'orea, French Polynesia, that differ in their relative abundance across depth. We constructed new phylogenies of the host Pocillopora (using complete mitochondrial genomes, genomic loci, and thousands of single nucleotide polymorphisms) and their Symbiodiniaceae symbionts (using ITS2 and psbAncr markers) and tested for cophylogeny. The analysis supported the presence of five Pocillopora species on the fore reef at Mo'orea that mostly hosted either Cladocopium latusorum or C. pacificum. Only Pocillopora species hosting C. latusorum also hosted taxa from Symbiodinium and Durusdinium. In general, the Cladocopium phylogeny mirrored the Pocillopora phylogeny. Within Cladocopium species, lineages also differed in their associations with Pocillopora haplotypes, except those showing evidence of nuclear introgression, and with depth in the two most common Pocillopora species. We also found evidence for a new Pocillopora species (haplotype 10), that has so far only been sampled from French Polynesia, that warrants formal identification. The linked phylogenies of these Pocillopora and Cladocopium species and lineages suggest that symbiont speciation is driven by niche diversification in the host, but there is still evidence for symbiont flexibility in some cases.

Bolus Versus Continuous Nasogastric Feeds for Infants With Bronchiolitis: A Randomized Trial.

BACKGROUND AND OBJECTIVES: Infants hospitalized with bronchiolitis are commenced on nasogastric feeding to maintain hydration. Feeding strategies vary according to physician or institution preference. The current study hypothesized that continuous nasogastric feeding would prolong length of stay (LOS) when compared to bolus feeding. METHODS: A randomized, parallel-group, superiority clinical trial was performed within an Australian children's hospital throughout 2 bronchiolitis seasons from May 2018 to October 2019. Infants <12 months hospitalized with bronchiolitis and requiring supplemental nasogastric feeding were randomly assigned to continuous or bolus nasogastric regimens. LOS was the primary outcome. Secondary outcome measures included pulmonary aspirations and admissions to intensive care. RESULTS: The intention-to-treat analysis included 189 patients: 98 in the bolus nasogastric feeding group and 91 in the continuous group. There was no significant difference in LOS (median LOS of the bolus group was 54.25 hours [interquartile range 40.25-82] and 56 hours [interquartile range 38-78.75] in the continuous group). A higher proportion of admissions to intensive care was detected in the continuous group (28.57% [26 of 91] of the continuous group vs 11.22% [11 of 98] of the bolus group [P value 0.004]). There were no clinically significant pulmonary aspirations or statistically significant differences in vital signs between the groups within 6 hours of feed initiation. CONCLUSIONS: No significant difference in LOS was found between bolus and continuous nasogastric feeding strategies for infants hospitalized with bronchiolitis. The continuous feeding group had a higher proportion of intensive care admissions, and there were no aspiration events.

Home (Level 2) polysomnography is feasible in children with suspected sleep disorders.

AIM: To audit the feasibility and patient experience of home polysomnography (sleep study) for the investigation of a sleep disorder in children. METHODS: The signal quality and outcomes of a Level 2 (home) polysomnography in young people undergoing investigation between September 2020 and January 2021 in a single centre was reviewed. A successful home polysomnogram was defined as a study with ≥6 h of sleep and all channels (EEG, thoraco-abdominal bands, calculated airflow, and pulse oximetry) present for at least 90% of the study time. Feedback from the guardian and young person was collected following the study using a questionnaire. RESULTS: Fifty-five patients, aged 4 months to 18 years, were included. A successful polysomnogram, on the first attempt, was achieved for 48/55 (87%) subjects. There were no differences in success when accounting for neurodevelopmental conditions, OSA severity or age. The majority (76%) of guardians felt that their child slept the same or better than normal and only 12% found having the study conducted at home difficult. Following the study, only 8% would have preferred a hospital sleep study in retrospect. CONCLUSIONS: Home polysomnography produced a technically adequate study for the majority of subjects. Most families also found the experience of having a home sleep study to be positive. These data support the use of home sleep studies as an alternative to an in-patient sleep study, in appropriate circumstances, for young people undergoing investigation of a sleep disorder.

Sleep, Function, Behaviour and Cognition in a Cohort of Children with Down Syndrome.

OBJECTIVE: To describe the sleep problems experienced by children with Down syndrome attending a tertiary sleep clinic and relationship with behaviour, function and cognition. METHODS: Data were collected from children with Down syndrome aged 3-18 years old. Carers completed the Abbreviated Child Sleep Habits Questionnaire, Child Behaviour Checklist and Life-Habits Questionnaire at enrolment. Cognitive assessment (Stanford-Binet 5) was undertaken by a trained psychologist. Children received management for their sleep problem as clinically indicated. RESULTS: Forty-two subjects with a median age of 6.8 years (Interquartile Range-IQR 4.5, 9.8) were enrolled. A total of 92% were referred with snoring or symptoms of Obstructive Sleep Apnoea (OSA), with 79% of those referred having had previous ENT surgery. Thus, 85% of all participants underwent a sleep study and 61% were diagnosed with OSA (OAHI ≥ 1/h). Based on questionnaires, 86% of respondents indicated that their child had a significant sleep disorder and non-respiratory sleep problems were common. Non-respiratory problems included: trouble going to sleep independently (45%), restless sleep (76%), night-time waking (24%) and bedtime resistance (22%). No significant correlations were found between sleep measures (behavioural and medical sleep problems) and the behavioural, functional or cognitive parameters. CONCLUSION: Sleep disorders were very common, especially non-respiratory sleep problems. OSA was common despite previous surgery. No association was found between sleep-related problems (snoring, sleep-study-confirmed OSA or non-respiratory sleep problem) and parent-reported behavioural problems, functional impairments or intellectual performance. This may reflect limitations of the measures used in this study, that in this population ongoing problems with daytime function are not sleep related or that a cross-sectional assessment does not adequately take into account the impacts of past disease/treatments. Further research is required to further evaluate the tools used to evaluate sleep disorders, the impact of those disorder on children with Down syndrome and interventions which improve both sleep and daytime function.

Behavioral Variability of Hatchlings Modifies Dispersal Potential in Crown Conch (Melongena corona): Why Do Larvae Crawl Away but Sometimes Swim?

AbstractThe diversity and consequences of development in marine invertebrates have, for a long time, provided the opportunity to understand different evolutionary solutions to living in variable environments. However, discrete classifications of development can impede a full understanding of adaptation to variable environments when behavioral, morphological, or physiological flexibility and variation exist within traditionally defined modes of development. We report here novel behavioral variability in hatchlings of a marine gastropod, the Florida crown conch (Melongena corona), that has broad significance for understanding the correlated evolution of development, dispersal, and reproductive strategies in variable environments. All hatchlings crawl away from egg capsules after emergence as larval pediveligers. Some subsequently swim for a brief period (seconds to minutes) before crawling again. From detailed observations of 120 individuals over 30 days, we observed 28 (23.3%) hatchlings swimming at least once (8%-50% per maternal brood). The propensity to swim was unrelated to time spent encapsulated or size at hatching and lasted for 22 days. We manipulated hypothesized environmental cues and found that the proportion of hatchlings that swam was highest in the absence of cues related to habitat or juvenile food and lowest when only habitat cues were present. The relative growth rate of hatchlings was highest when habitats contained a putative juvenile food source. About 44% of hatchlings were competent to metamorphose at emergence but did not metamorphose at this time in the lab or the field. The rate of metamorphosis increased with age and depended on the presence of unknown cues in the field. Crawl-away larvae with prolonged swimming ability may be an adaptation to balance the unpredictable risks of exclusively benthic or pelagic development and to allow the option to disperse to higher-quality habitat.

Response diversity in corals: hidden differences in bleaching mortality among cryptic Pocillopora species.

Variation among functionally similar species in their response to environmental stress buffers ecosystems from changing states. Functionally similar species may often be cryptic species representing evolutionarily distinct genetic lineages that are morphologically indistinguishable. However, the extent to which cryptic species differ in their response to stress, and could therefore provide a source of response diversity, remains unclear because they are often not identified or are assumed to be ecologically equivalent. Here, we uncover differences in the bleaching response between sympatric cryptic species of the common Indo-Pacific coral, Pocillopora. In April 2019, prolonged ocean heating occurred at Moorea, French Polynesia. 72% of pocilloporid colonies bleached after 22 d of severe heating (>8o C-days) at 10 m depth on the north shore fore reef. Colony mortality ranged from 11% to 42% around the island four months after heating subsided. The majority (86%) of pocilloporids that died from bleaching belonged to a single haplotype, despite twelve haplotypes, representing at least five species, being sampled. Mitochondrial (open reading frame) sequence variation was greater between the haplotypes that experienced mortality versus haplotypes that all survived than it was between nominal species that all survived. Colonies > 30 cm in diameter were identified as the haplotype experiencing the most mortality, and in 1125 colonies that were not genetically identified, bleaching and mortality increased with colony size. Mortality did not increase with colony size within the haplotype suffering the highest mortality, suggesting that size-dependent bleaching and mortality at the genus level was caused instead by differences among cryptic species. The relative abundance of haplotypes shifted between February and August, driven by declines in the same common haplotype for which mortality was estimated directly, at sites where heat accumulation was greatest, and where larger colony sizes occurred. The identification of morphologically indistinguishable species that differ in their response to thermal stress, but share a similar ecological function in terms of maintaining a coral-dominated state, has important consequences for uncovering response diversity that drives resilience, especially in systems with low or declining functional diversity.

Sleep problems in Australian children with Down syndrome: the need for greater awareness.

BACKGROUND: Children with Down Syndrome (DS) have a high prevalence of obstructive sleep apnoea (OSA). Non-respiratory sleep disorders also occur commonly but are less well recognised. This cross-sectional study evaluates the prevalence of sleep difficulties in a community sample of Australian children with DS (DScomm), using the Children's Sleep Habits Questionnaire (CSHQ), and compares them to children referred to the sleep clinic (DSref). To our knowledge this is the first study to have reported prevalence of sleep problems in Australian children with DS and to compare a community and referred group of children with DS directly. METHODS: The CSHQ was completed by parents of children with DS recruited from the community (DScomm) via survey distributed by Down syndrome Queensland and Australia. A second group was recruited through the tertiary sleep clinic at our institution (DSref) and completed the same questionnaire on enrolment. Data from these groups was compared. RESULTS: There were 76 participants in the DScomm group (57% male; median age 9.7yrs) and 42 participants in the DSref group (50% male; median age 6.97yrs). The overall prevalence of sleep disturbances was 90.9% in the DScomm group, and 85.7% in the DSref group (p = 0.54). There was a statistically significant difference in the mean total CSHQ score, with the DScomm having the higher score (p = 0.023). CONCLUSIONS: This study reports a high prevalence of sleep problems in both a community and referred group of Australian children with DS and suggests that there are many children with DS with sleep problems, particularly non-respiratory difficulties, who are potentially not receiving adequate treatment.

Global biogeography of marine dispersal potential.

The distance travelled by marine larvae varies by seven orders of magnitude. Dispersal shapes marine biodiversity, and must be understood if marine systems are to be well managed. Because warmer temperatures quicken larval development, larval durations might be systematically shorter in the tropics relative to those at high latitudes. Nevertheless, life history and hydrodynamics also covary with latitude-these also affect dispersal, precluding any clear expectation of how dispersal changes at a global scale. Here we combine data from the literature encompassing >750 marine organisms from seven phyla with oceanographic data on current speeds, to quantify the overall latitudinal gradient in larval dispersal distance. We find that planktonic duration increased with latitude, confirming predictions that temperature effects outweigh all others across global scales. However, while tropical species have the shortest planktonic durations, realized dispersal distances were predicted to be greatest in the tropics and at high latitudes, and lowest at mid-latitudes. At high latitudes, greater dispersal distances were driven by moderate current speed and longer planktonic durations. In the tropics, fast currents overwhelmed the effect of short planktonic durations. Our results contradict previous hypotheses based on biology or physics alone; rather, biology and physics together shape marine dispersal patterns.

The impact of sleep problems on functional and cognitive outcomes in children with Down syndrome: a review of the literature.

STUDY OBJECTIVES: The aim of this review was to summarize the existing literature on the association between sleep problems and cognition, function, and behavior in children with Down syndrome. METHODS: Embase, PubMed, CINAHL, and PsychINFO databases were searched to retrieve all studies published between 1990 and 2018 that evaluated the relationship between sleep and cognition, function, or behavior in children with Down syndrome. RESULTS: Fifteen articles were included, which were mostly of a cohort or case-controlled design. Five articles addressed sleep and cognition only, 6 reported on sleep and behavior, and only 1 reported on sleep and functional ability. Three papers evaluated sleep and both cognition and behavior. Findings varied across studies with methodological differences, making it difficult to directly compare results. The association between sleep and behavior or cognition in children with Down syndrome remains uncertain, but a large study in 110 children provides strong evidence of a negative impact of sleep disorders on the accomplishment of daily life habits. CONCLUSIONS: The impact of coexisting sleep disorders in children with Down syndrome has not been widely studied, with only 15 relevant studies found through an extensive literature review. Large well-designed studies are required to fully understand this relationship further. This is important as sleep-disordered breathing and difficulties with sleep patterns and routines are highly prevalent in children with Down syndrome. Sleep may be one of the few treatable factors that can assist in improving long-term outcomes in this population.

Inbreeding shapes the evolution of marine invertebrates.

Inbreeding is a potent evolutionary force shaping the distribution of genetic variation within and among populations of plants and animals. Yet, our understanding of the forces shaping the expression and evolution of nonrandom mating in general, and inbreeding in particular, remains remarkably incomplete. Most research on plant mating systems focuses on self-fertilization and its consequences for automatic selection, inbreeding depression, purging, and reproductive assurance, whereas studies of animal mating systems have often assumed that inbreeding is rare, and that natural selection favors traits that promote outbreeding. Given that many sessile and sedentary marine invertebrates and marine macroalgae share key life history features with seed plants (e.g., low mobility, modular construction, and the release of gametes into the environment), their mating systems may be similar. Here, we show that published estimates of inbreeding coefficients (FIS ) for sessile and sedentary marine organisms are similar and at least as high as noted in terrestrial seed plants. We also found that variation in FIS within invertebrates is related to the potential to self-fertilize, disperse, and choose mates. The similarity of FIS for these organismal groups suggests that inbreeding could play a larger role in the evolution of sessile and sedentary marine organisms than is currently recognized. Specifically, associations between traits of marine invertebrates and FIS suggest that inbreeding could drive evolutionary transitions between hermaphroditism and separate sexes, direct development and multiphasic life cycles, and external and internal fertilization.