9 results on '"Larsen M"'
Search Results
2. Data-informed targets for suicide prevention: a small-area analysis of high-risk suicide regions in Australia.
- Author
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Torok, Michelle, Shand, F., Phillips, M., Meteoro, N., Martin, D., and Larsen, M.
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SUICIDE statistics ,SUICIDE prevention ,SUICIDE ,ECONOMIC indicators - Abstract
Purpose: To investigate small-area variation in risks associated with suicide deaths across four regional communities in New South Wales, Australia, and to determine whether these areas have unique demographic and socioeconomic risk profiles that could inform targeted means restriction suicide prevention efforts.Methods: Archival data on suicide mortality for all deaths in New South Wales, Australia, over the period 2006-2015 were geospatially attributed to four high-risk priority regions. Deaths in the four regions were compared to each other, and to NSW, on demographic factors, indicators of economic deprivation, and suicide means.Results: Priority means restriction targets were identified for all sites. In Murrumbidgee, suicide deaths were significantly more likely to involve firearms and older males (p < 0.001). The Central Coast had a greater proportion of overdose deaths (p < 0.001), which were associated with being female and unemployed. Suicide deaths in Newcastle were associated with being younger (p = 0.001) and involving 'jumping from a height' (p < 0.001), while economic deprivation was a major risk for suicide death in Illawarra Shoalhaven (p < 0.001).Conclusions: Local regions were significantly differentiated from each other, and from the State, in terms of priority populations and means of suicide, demonstrating the need for locally based, targeted interventions. There were, however, also some risk constancies across all sites (males, hanging, economic deprivation), suggesting that prevention initiatives should, optimally, be delivered within multilevel models that target risk commonalities and provide tailored initiatives that address risk specific to a region. [ABSTRACT FROM AUTHOR]- Published
- 2019
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3. Age-stratified predictions of suicide attempts using machine learning in middle and late adolescence.
- Author
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Kusuma K, Larsen M, Quiroz JC, and Torok M
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- Humans, Adolescent, Female, Male, Longitudinal Studies, Australia epidemiology, Age Factors, Child, Young Adult, Risk Factors, Logistic Models, Suicide, Attempted statistics & numerical data, Machine Learning
- Abstract
Background: Prevalence of suicidal behaviour increases rapidly in middle to late adolescence. Predicting suicide attempts across different ages would enhance our understanding of how suicidal behaviour manifests in this period of rapid development. This study aimed to develop separate models to predict suicide attempts within a cohort at middle and late adolescence. It also sought to examine differences between the models derived across both developmental stages., Methods: This study used data from the nationally representative Longitudinal Study of Australian Children (N = 2266). We selected over 700 potential suicide attempt predictors measured via self-report questionnaires, and linked healthcare and education administrative datasets. Logistic regression, random forests, and gradient boosting algorithms were developed to predict suicide attempts across two stages (mid-adolescence: 14-15 years; late adolescence: 18-19 years) using predictors sampled two years prior (mid-adolescence: 12-13 years; late adolescence: 16-17 years)., Results: The late adolescence models (AUROC = 0.77-0.88, F1-score = 0.22-0.28, Sensitivity = 0.54-0.64) performed better than the mid-adolescence models (AUROC = 0.70-0.76, F1-score = 0.12-0.19, Sensitivity = 0.40-0.64). The most important features for predicting suicide attempts in mid-adolescence were mostly school-related, while the most important features in late adolescence included measures of prior suicidality, psychosocial health, and future plans., Conclusions: To date, this is the first study to use machine learning models to predict suicide attempts at different ages. Our findings suggest that the optimal suicide risk prediction model differs by stage of adolescence. Future research and interventions should consider that risk presentations can change rapidly during adolescence., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
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- 2024
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4. The Effect of Explicit Suicide Language in Engagement With a Suicide Prevention Search Page Help-Seeking Prompt: Nonrandomized Trial.
- Author
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Onie S, Armstrong SO, Josifovski N, Berlinquette P, Livingstone N, Holland S, Finemore C, Gale N, Elder E, Laggis G, Heffernan C, Theobald A, Torok M, Shand F, and Larsen M
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- Humans, Suicidal Ideation, Australia, Language, Suicide Prevention, Suicide
- Abstract
Background: Given that signage, messaging, and advertisements (ads) are the gateway to many interventions in suicide prevention, it is important that we understand what type of messaging works best for whom., Objective: We investigated whether explicitly mentioning suicide increases engagement using internet ads by investigating engagement with campaigns with different categories of keywords searched, which may reflect different cognitive states., Methods: We ran a 2-arm study Australia-wide, with or without ads featuring explicit suicide wording. We analyzed whether there were differences in engagement for campaigns with explicit and nonexplicit ads for low-risk (distressed but not explicitly suicidal), high-risk (explicitly suicidal), and help-seeking for suicide keywords., Results: Our analyses revealed that having explicit wording has opposite effects, depending on the search terms used: explicit wording reduced the engagement rate for individuals searching for low-risk keywords but increased engagement for those using high-risk keywords., Conclusions: The findings suggest that individuals who are aware of their suicidality respond better to campaigns that explicitly use the word "suicide." We found that individuals who search for low-risk keywords also respond to explicit ads, suggesting that some individuals who are experiencing suicidality search for low-risk keywords., (©Sandersan Onie, Susanne Oliver Armstrong, Natasha Josifovski, Patrick Berlinquette, Nicola Livingstone, Sarah Holland, Coco Finemore, Nyree Gale, Emma Elder, George Laggis, Cassandra Heffernan, Adam Theobald, Michelle Torok, Fiona Shand, Mark Larsen. Originally published in JMIR Mental Health (https://mental.jmir.org), 19.03.2024.)
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- 2024
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5. Efficacy of BrighterSide, a Self-Guided App for Suicidal Ideation: Randomized Controlled Trial.
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Josifovski N, Torok M, Batterham P, Wong Q, Beames JR, Theobald A, Holland S, Huckvale K, Riley J, Cockayne N, Christensen H, and Larsen M
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- Adult, Humans, Australia, Coping Skills, Suicidal Ideation, Middle Aged, Aged, Mobile Applications, Self-Injurious Behavior
- Abstract
Background: Self-guided digital interventions can reduce the severity of suicidal ideation, although there remain relatively few rigorously evaluated smartphone apps targeting suicidality., Objective: This trial evaluated whether the BrighterSide smartphone app intervention was superior to a waitlist control group at reducing the severity of suicidal ideation., Methods: A total of 550 adults aged 18 to 65 years with recent suicidal ideation were recruited from the Australian community. In this randomized controlled trial, participants were randomly assigned to receive either the BrighterSide app or to a waitlist control group that received treatment as usual. The app was self-guided, and participants could use the app at their own pace for the duration of the study period. Self-report measures were collected at baseline, 6 weeks, and 12 weeks. The primary outcome was severity and frequency of suicidal ideation, and secondary outcomes included psychological distress and functioning and recovery. Additional data were collected on app engagement and participant feedback., Results: Suicidal ideation reduced over time for all participants, but there was no significant interaction between group and time. Similar improvements were observed for self-harm, functioning and recovery, days out of role, and coping. Psychological distress was significantly lower in the intervention group at the 6-week follow-up, but this was not maintained at 12 weeks., Conclusions: The BrighterSide app did not lead to a significant improvement in suicidal ideation relative to a waitlist control group. Possible reasons for this null finding are discussed., (© Natasha Josifovski, Michelle Torok, Philip Batterham, Quincy Wong, Joanne Beames, Adam Theobald, Sarah Holland, Kit Huckvale, Jo Riley, Nicole Cockayne, Helen Christensen, Mark Larsen. Originally published in JMIR Mental Health (https://mental.jmir.org).)
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- 2024
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6. Understanding suicidal transitions in Australian adults: protocol for the LifeTrack prospective longitudinal cohort study.
- Author
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Batterham PJ, Gendi M, Christensen H, Calear AL, Shand F, Sunderland M, Borschmann R, Banfield M, O'Dea B, Larsen M, Heffernan C, Kazan D, Werner-Seidler A, Mackinnon AJ, Hielscher E, Han J, Boydell KM, Leach L, and Farrer LM
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- Adult, Humans, Prospective Studies, Longitudinal Studies, Australia, Risk Factors, Psychological Theory, Interpersonal Relations, Suicidal Ideation, Suicide, Attempted prevention & control, Suicide, Attempted psychology
- Abstract
Background: The factors that influence transition from suicidal ideation to a suicide attempt or remission of suicidal thoughts are poorly understood. Despite an abundance of research on risk factors for suicidal ideation, no large-scale longitudinal population-based studies have specifically recruited people with suicidal ideation to examine the mechanisms underlying critical transitions to either suicide attempt or recovery from suicidal ideation. Without longitudinal data on the psychological, behavioural, and social determinants of suicide attempt and the remission of suicidal ideation, we are unlikely to see major gains in the prevention of suicide., Aim: The LifeTrack Project is a population-based longitudinal cohort study that aims to identify key modifiable risk and protective factors that predict the transition from suicidal ideation to suicide attempt or remission of suicidal ideation. We will assess theory-informed risk and protective factors using validated and efficient measures to identify distinct trajectories reflecting changes in severity of suicidal ideation and transition to suicide attempt over three years., Methods: A three-year prospective population-based longitudinal cohort study will be conducted with adults from the general Australian population who initially report suicidal ideation (n = 842). Eligibility criteria include recent suicidal ideation (past 30 days), aged 18 years or older, living in Australia and fluent in English. Those with a suicide attempt in past 30 days or who are unable to participate in a long-term study will be excluded. Participants will be asked to complete online assessments related to psychopathology, cognition, psychological factors, social factors, mental health treatment use, and environmental exposures at baseline and every six months during this three-year period. One week of daily measurement bursts (ecological momentary assessments) at yearly intervals will also capture short-term fluctuations in suicidal ideation, perceived burdensomeness, thwarted belongingness, capability for suicide, and distress., Conclusion: This study is intended to identify potential targets for novel and tailored therapies for people experiencing suicidal ideation and improve targeting of suicide prevention programs. Even modest improvements in current treatments may lead to important reductions in suicide attempts and deaths., Study Registration: Australian New Zealand Clinical Trials Registry identifier: ACTRN12623000433606., (© 2023. The Author(s).)
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- 2023
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7. Biological control of nematode parasites in sheep.
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Larsen M
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- Animals, Anthelmintics, Australia, Denmark, Feces microbiology, Feces parasitology, Malaysia, Nematode Infections prevention & control, Nematode Infections therapy, Sheep Diseases parasitology, Sheep Diseases therapy, Spores, Fungal physiology, Tropical Climate, Ascomycota physiology, Nematoda microbiology, Nematode Infections veterinary, Pest Control, Biological methods, Sheep Diseases prevention & control
- Abstract
In a world in which sheep producers are facing increasing problems due to the rapid spread of anthelmintic resistance, the battle against gastrointestinal parasitic nematodes is a difficult one. One of the potential new tools for integrated control strategies is biological control by means of the nematode-destroying microfungus Duddingtonia flagrans. This fungus forms sticky traps that catch developing larval stages of parasitic nematodes in the fecal environment. When resting spores (chlamydospores) of this fungus are fed daily to grazing animals for a period of time, the pasture infectivity and thus, the worm burden of grazing animals are lowered, especially in young lambs. Research has been conducted throughout the world covering many different climates and management systems. An Australian parasite model showed that if the fungus performs efficiently (> or =90% reduction in worm burden) for 2 or 3 mo, it should contribute significantly to a reduction in the number of dead lambs otherwise occurring when managed only by anthelmintic treatment and grazing management. Feeding or field trials have clearly demonstrated that dosing with a few hundred thousand spores per kilogram of live BW not only reduced the number of infective larvae but also increased the BW of the lambs compared with controls not given fungus. Initial Australian work with feeding spores by means of a block formulation or a slow-release device has shown some promise, but further work is needed to fully develop these delivery systems. In tropical Malaysia, small paddock trials and field studies resulted in significant improvements, in terms of lower worm burdens and increased live BW, when feeding half a million spores daily to grazing lambs. Additional benefits have been observed when the fungus is employed in combination with a fast rotational grazing system. Research has also demonstrated that spores can be delivered in slightly moist feed block material, but only if such blocks are consumed rapidly, because of their very short shelf life. In the northern, temperate Danish climate it has been demonstrated that daily feeding of half a million spores per kilogram of live BW can lead to significant production benefits, with increased live BW gain in fungus-exposed animals. Biological control of parasitic nematodes in sheep seems to hold promise for the future, but to be able to assist producers, the optimal delivery system needs to be refined and further developed. In addition, more work will be needed to define the best use of this technology in different geographic regions.
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- 2006
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8. The potential of nematophagous fungi to control the free-living stages of nematode parasites of sheep: comparison between Australian isolates of Arthrobotrys spp. and Duddingtonia flagrans.
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Faedo M, Larsen M, and Waller PJ
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- Animals, Australia, Larva, Sheep, Species Specificity, Trichostrongylosis prevention & control, Trichostrongylus growth & development, Trichostrongylus isolation & purification, Mitosporic Fungi isolation & purification, Pest Control, Biological, Sheep Diseases prevention & control, Trichostrongylosis veterinary
- Abstract
Nine isolates of Duddingtonia flagrans and eight isolates of Arthrobotrys spp. which originated from a field survey for the presence of nematophagous fungi in fresh dung of livestock in Australia were used in this study. Comparisons were made between the ability of the different isolates to survive gut passage and subsequently reduce infective larval numbers in sheep faeces. Fungal spores (conidia and/or chlamydospores) were administered orally to sheep in doses ranging from 1 X 10(5) to 4.5 X 10(6) spores. There was no apparent consistent survival of Arthrobotrys spp., whereas D. flagrans showed excellent survival capacity which resulted in profound reductions in Trichostrongylus colubriformis larval numbers in culture. This provides clear evidence that D. flagrans is an ideal candidate as a potential biological control agent for nematode parasites of sheep.
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- 1997
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9. The potential of nematophagous fungi to control the free-living stages of nematode parasites of sheep: survey for the presence of fungi in fresh faeces of grazing livestock in Australia.
- Author
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Larsen M, Faedo M, and Waller PJ
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- Animal Husbandry, Animals, Australia, Pest Control, Biological, Ruminants microbiology, Ruminants parasitology, Feces microbiology, Mitosporic Fungi isolation & purification, Mitosporic Fungi physiology, Nematoda growth & development, Sheep microbiology, Sheep parasitology
- Abstract
In the course of 12 months, 1742 fresh faecal samples from grazing livestock, principally ruminants, from various States of Australia were examined for the presence of nematophagous fungi. In total, 48 separate isolations were made representing various species from the genus Arthrobotrys and also 16 isolates of the single Duddingtonia species, Duddingtonia flagrans. These isolates will be used in continuing studies to select the most suitable species, on the basis of nematophagous capability and ruminant gut survival capacity, for development of a biological means of controlling nematode parasites of livestock.
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- 1994
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