565 research outputs found
Determining energy expenditure in a large seabird using accelerometry
Funding The research was financially supported by the Holsworth Wildlife Research Endowment. Open Access funding provided by La Trobe University. Deposited in PMC for immediate release. Acknowledgements We thank the Victorian Marine Science Consortium, Sea All Dolphin Swims, and Parks Victoria for logistical support. Catherine Hambly and Peter Thomson provided technical support for the DLW isotope analysis. Aspects of the results and discussion in this paper are reproduced from the PhD thesis of L.P.A. (Angel, 2015).Peer reviewedPublisher PD
Benefits of group foraging depend on prey type in a small marine predator, the Little Penguin
Group foraging provides predators with advantages in over-powering prey larger than themselves or in aggregating small prey for efficient exploitation. For group-living predatory species, cooperative hunting strategies provide inclusive fitness benefits. However, for colonial-breeding predators, the benefit pay-offs of group foraging are less clear due to the potential for intra-specific competition. We used animal-borne cameras to determine the prey types, hunting strategies, and success of little penguins (Eudyptula minor), a small, colonial breeding air-breathing marine predator that has recently been shown to display extensive at-sea foraging associations with conspecifics. Regardless of prey type, little penguins had a higher probability of associating with conspecifics when hunting prey that were aggregated than when prey were solitary. In addition, success was greater when individuals hunted schooling rather than solitary prey. Surprisingly, however, success on schooling prey was similar or greater when individuals hunted on their own than when with conspecifics. These findings suggest individuals may be trading-off the energetic gains of solitary hunting for an increased probability of detecting prey within a spatially and temporally variable prey field by associating with conspecifics
Departure time influences foraging associations in little penguins
Recent studies have documented that little penguins (Eudyptula minor) associate at sea, displaying synchronised diving behaviour throughout a foraging trip. However, previous observations were limited to a single foraging trip where only a small number of individuals were simultaneously tracked. Consequently, it is not known whether coordinated behaviour is consistent over time, or what factors influence it. In the present study, breeding adults were concurrently instrumented with GPS and dive behaviour data loggers for at least 2 consecutive foraging trips during guard and post-guard stage at two breeding colonies (London Bridge and Gabo Island, south-eastern Australia) of contrasting population size (approximately 100 and 30,000-40,000, respectively). At both colonies, individuals were sampled in areas of comparable nesting density and spatial area. At London Bridge, where individuals use a short (23 m) common pathway from their nests to the shoreline, > 90% (n = 42) of birds displayed foraging associations and 53-60% (n = 20) maintained temporally consistent associations with the same conspecifics. Neither intrinsic (sex, size or body condition) nor extrinsic (nest proximity) factors were found to influence foraging associations. However, individuals that departed from the colony at a similar time were more likely to associate during a foraging trip. At Gabo Island, where individuals use a longer (116 m) pathway with numerous tributaries to reach the shoreline, few individuals (< 31%; n = 13) from neighbouring nests associated at sea and only 1% (n = 1) maintained associations over subsequent trips. However, data from animal-borne video cameras indicated individuals at this colony displayed foraging associations of similar group size to those at London Bridge. This study reveals that group foraging behaviour occurs at multiple colonies and the pathways these individuals traverse with conspecifics may facilitate opportunistic group formation and resulting in foraging associations irrespective of nesting proximity and other factors
Multicomponent frailty assessment tools for older people with psychiatric disorders: a systematic review
Objective: To review evidence evaluating the use of multi-component frailty assessment tools in assessing frailty in older adults with psychiatric disorders. Methods: A systematic literature review was conducted to identify all multi-component frailty assessment tools (i.e. a tool that assesses ≥2 indicators of frailty). The items of each frailty assessment tool were compared to DSM-5 diagnostic criteria for psychiatric disorders to assess construct overlap. Studies conducted in community, inpatient and outpatient clinical settings were considered for inclusion. Participants: Adults aged ≥60 years old. Results: 5,639 studies in total were identified following the removal of duplicates; 97 of which were included for review. Of the 48 multi-component frailty assessment tools identified, no tool had been developed for, or validated in, older adult populations with psychiatric disorder. 24/48 frailty assessment tools contained a psychological assessment domain, with 18/48 tools using presence of depressed mood and/or anxiety as a frailty indicator. Common areas of construct overlap in frailty assessment tools and DSM-5 diagnostic criteria included weight loss (29/48) and fatigue (21/48). Conclusions: Significant construct overlap exists between the indicators of frailty as conceptualised in existing frailty assessment tools and DSM-5 diagnostic criteria for common psychiatric disorders, including Major Depressive Episode and Generalised Anxiety Disorder, which has the potential to confound frailty assessment results. Further research is necessary to establish a reliable and valid tool to assess frailty in this population
The Acinetobacter baumannii two-component system aders regulates genes required for multidrug efflux, biofilm formation, and virulence in a strain-specific manner
The opportunistic pathogen Acinetobacter baumannii is able to persist in the environment and is often multidrug resistant (MDR), causing difficulties in the treatment of infections. Here, we show that the two-component system AdeRS, which regulates the production of the AdeABC multidrug resistance efflux pump, is required for the formation of a protective biofilm in an ex vivo porcine mucosal model, which mimics a natural infection of the human epithelium. Interestingly, deletion of adeB impacted only on the ability of strain AYE to form a biofilm on plastic and only on the virulence of strain Singapore 1 for Galleria mellonella. RNA-Seq revealed that loss of AdeRS or AdeB significantly altered the transcriptional landscape, resulting in the changed expression of many genes, notably those associated with antimicrobial resistance and virulence interactions. For example, A. baumannii lacking AdeRS displayed decreased expression of adeABC, pil genes, com genes, and a pgaC-like gene, whereas loss of AdeB resulted in increased expression of pil and com genes and decreased expression of ferric acinetobactin transport system genes. These data define the scope of AdeRS-mediated regulation, show that changes in the production of AdeABC mediate important phenotypes controlled by AdeRS, and suggest that AdeABC is a viable target for antimicrobial drug and antibiofilm discovery. IMPORTANCE Acinetobacter baumannii is a nosocomial pathogen and is an increasing problem in hospitals worldwide. This organism is often multidrug resistant, can persist in the environment, and forms a biofilm on environmental surfaces and wounds. Overproduction of efflux pumps can allow specific toxic compounds to be pumped out of the cell and can lead to multidrug resistance. This study demonstrates the role of the A. baumannii efflux pump AdeB, and its regulator AdeRS, in multidrug resistance, epithelial cell killing, and biofilm formation. Deletion of the genes encoding these systems led to increased susceptibility to antibiotics, decreased biofilm formation on biotic and abiotic surfaces, and decreased virulence. Our data suggest that inhibition of AdeB could prevent biofilm formation or colonization in patients by A. baumannii and provides a good target for drug discovery
Advancing care and support for women and families after stillbirth or neonatal death in Kenya and Uganda: A feasibility study
Background
Approximately every 16 seconds a baby dies, before, during or shortly after birth globally. Over 98% of stillbirths and neonatal deaths occur in low- and middle-income countries, with over 75% in sub-Saharan Africa and South Asia. Alongside prevention, providing respectful and appropriate bereavement support to parents is a key global priority for equitable care and outcomes. Previous studies in sub-Saharan Africa, including Kenya and Uganda, demonstrate limited bereavement support in facilities and stigma surrounding perinatal death in communities. There is an urgent need for context-appropriate interventions to improve emotional and psychological support for bereaved parents in these settings.
Objectives
To assess the feasibility of implementation, and a full-scale effectiveness evaluation of a co-produced multicomponent intervention to improve perinatal bereavement support in Kenya and Uganda.
Design
A prospective, observational, mixed-methods feasibility study, using a pre- and post-cohort design. Community engagement and involvement was embedded throughout the research process.
Setting
Two tertiary urban maternity facilities and surrounding communities in Kenya and Uganda.
Participants
Postnatal women experiencing stillbirth or early neonatal death in the included facilities.
Intervention
Two components including (1) introduction of trained health worker ‘bereavement champions’ in facilities, focused on developing care for bereaved women and families through individual and collective action and (2) access to telephone peer support for women, post discharge, from trained peers in communities.
Main outcome measures
The primary feasibility outcome measures were recruitment and retention of women. Secondary outcomes included acceptability of the intervention and research processes, feasibility of data collection, characteristics of the proposed evaluation trial primary outcome measure and quality of implementation.
Results
Over the study period, November 2019 to December 2020, a total of 501 women experienced stillbirth or early neonatal death in the included facilities, 208 women consented to be contacted for participation in the study and 107 were recruited; 56 women experiencing usual postnatal care and 51 offered the study intervention. Despite the COVID-19 pandemic, recruitment was 89% of the target and 85% of participants completed the study. The intervention was implemented largely as planned and was generally acceptable to women, families, health workers and others involved. Key learning points included the need for education for a wider group of health workers to increase understanding of principles of effective bereavement support and involving more clinical leaders as bereavement champions, to add leverage for change in practice. Research processes and data collection tools, including the selected psychological measures, were also acceptable. Women and families welcomed the opportunity to participate in research to improve care.
Limitations
This study was impacted by COVID-19, which disrupted aspects of recruitment, intervention implementation and data collection. The focus on urban settings in both countries is a potential limitation to transferability of findings.
Conclusions
This study demonstrated the feasibility of implementation and of a larger-scale effectiveness evaluation of the co-produced multicomponent intervention. Learning from this feasibility study will be used to refine the intervention to improve context-appropriateness.
Future work
A pragmatic stepped-wedge cluster-randomised controlled trial, with parallel economic and process evaluations is proposed to assess the clinical and cost effectiveness of the intervention and explore future scale-up and sustainability
Metabolic Complementarity and Genomics of the Dual Bacterial Symbiosis of Sharpshooters
Mutualistic intracellular symbiosis between bacteria and insects is a widespread phenomenon that has contributed to the global success of insects. The symbionts, by provisioning nutrients lacking from diets, allow various insects to occupy or dominate ecological niches that might otherwise be unavailable. One such insect is the glassy-winged sharpshooter (Homalodisca coagulata), which feeds on xylem fluid, a diet exceptionally poor in organic nutrients. Phylogenetic studies based on rRNA have shown two types of bacterial symbionts to be coevolving with sharpshooters: the gamma-proteobacterium Baumannia cicadellinicola and the Bacteroidetes species Sulcia muelleri. We report here the sequencing and analysis of the 686,192–base pair genome of B. cicadellinicola and approximately 150 kilobase pairs of the small genome of S. muelleri, both isolated from H. coagulata. Our study, which to our knowledge is the first genomic analysis of an obligate symbiosis involving multiple partners, suggests striking complementarity in the biosynthetic capabilities of the two symbionts: B. cicadellinicola devotes a substantial portion of its genome to the biosynthesis of vitamins and cofactors required by animals and lacks most amino acid biosynthetic pathways, whereas S. muelleri apparently produces most or all of the essential amino acids needed by its host. This finding, along with other results of our genome analysis, suggests the existence of metabolic codependency among the two unrelated endosymbionts and their insect host. This dual symbiosis provides a model case for studying correlated genome evolution and genome reduction involving multiple organisms in an intimate, obligate mutualistic relationship. In addition, our analysis provides insight for the first time into the differences in symbionts between insects (e.g., aphids) that feed on phloem versus those like H. coagulata that feed on xylem. Finally, the genomes of these two symbionts provide potential targets for controlling plant pathogens such as Xylella fastidiosa, a major agroeconomic problem, for which H. coagulata and other sharpshooters serve as vectors of transmission
Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial
Background
Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
Hepatitis Vaccination of Men Who Have Sex with Men at Gay Pride Events
Prevention researchers have advocated primary prevention such as vaccination in alternative venues. However, there have been major questions about both the attendance of, and the ability to, vaccinate high-risk individuals in such settings. The current study seeks to assess the feasibility of vaccinating high-risk men who have sex with men (MSM) at Gay Pride events. The research questions are: Do gay men who are sampled at Gay Pride events engage in more or less risky behavior than gay men sampled at other venues? Do the gay men who receive hepatitis vaccinations at Gay Pride engage in more or less risky behavior than gay men at Gay Pride who do not receive hepatitis vaccination? Of the 3689 MSM that completed the Field Risk Assessment (FRA), 1095/3689 = 29.68% were recruited at either the 2006 or 2007 Long Beach, California Gay Pride events. The remaining, 2594/3689 = 70.32% were recruited at Long Beach gay bars, gay community organizations and institutions, and through street recruitment in various gay enclaves in the Long Beach area. Logistic regression analysis yielded eight factors that were associated with non-attendance of Gay Pride: Age, had sex while high in the last 12 months, had unprotected anal intercourse (UAI) in the last 12 months, had sex for drugs/money in the last 12 months, been diagnosed with a sexually transmitted infection (STI) in the last 12 months, used nitrites (poppers) in the last 12 months, and used methamphetamine in the last 12 months. Identifying as White, Asian, or African American compared to Hispanic was also associated with non-attendance. Bivariate analysis indicated that, of the MSM sampled at Gay Pride, 280/1095 = 25.57% received a hepatitis vaccination there. The MSM sampled at Gay Pride who reported engaging in UAI or having used any stimulant (cocaine, crack-cocaine, or methamphetamine) in the last 12 months were more likely to receive hepatitis vaccination on-site. The results provide evidence for the viability of successfully vaccinating high-risk MSM at Gay Pride events. However, it is vital that no-cost vaccinations are also funded in other community settings such as STI clinics, drug treatment programs, prisons, universities, and other community resource centers in order to reach those additional high-risk MSM who do not attend Gay Pride
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