114 research outputs found
A Near-Total Decline in Caribou on Prince of Wales, Somerset, and Russell Islands, Canadian Arctic
The number of caribou (Rangifer tarandus) on Prince of Wales, Somerset, and Russell islands in the south-central Canadian Arctic declined by 98% in 15 years, from an estimated 6048 (16% calves) in 1980 to an estimated 100 (0% calves) in 1995. Those estimates were obtained by systematic aerial surveys that used the same design and methods and comparable survey coverage. We do not have the data needed to determine the rate of decrease between 1980 and 1995 or its possible causes. There is no evidence for large-scale winter mortality in any one year or few consecutive years. A probable explanation for the decline is consequential reductions in long-term survival rates, both of breeding females and of calves in their first year of life, associated with continued caribou harvesting and markedly increased wolf (Canis lupus) predation on the dwindling number of caribou through the 1980s and early 1990s. The delay in detecting the decline and the lack of understanding of its causes will handicap the development of an ecologically sound recovery plan. As previous caribou declines have been followed by recovery, some comfort may be drawn from the likelihood of unaided recovery. However, the number of caribou has declined to the point where recovery will be tenuous and lengthy, at best. Unaided recovery could easily fail to occur, so we should not be complacent, especially as extirpation of these few remaining caribou would remove a distinct genetic group and reduce the biodiversity of caribou on Canada’s Arctic Islands.Le nombre de caribous (Rangifer tarandus) se trouvant sur les îles Prince of Wales, Somerset et Russell, dans le centresud de l’Arctique canadien, a chuté de 98 % en 15 ans, passant d’un nombre estimé à 6 048 (dont 16 % étaient des veaux) en 1980 à un nombre estimé à 100 (dont aucun veau) en 1995. Ces estimations ont été obtenues au moyen de relevés aériens systématiques recourant aux mêmes définitions, aux mêmes méthodes et à des aires de relevés comparables. On ne possède pas les données nécessaires pour déterminer le taux de diminution entre 1980 et 1995 ou les causes possibles de cette diminution. Par ailleurs, rien n’indique qu’un taux de mortalité hivernal élevé a été enregistré pendant une année quelconque ou pendant quelques années de suite. Il se peut que le déclin du nombre de caribous enregistré dans les années 1980 et au début des années 1990 soit attribuable aux réductions correspondantes des taux de survie à long terme chez les femelles de reproduction et les veaux pendant leur première année de vie, le tout jumelé au prélèvement continuel des caribous ainsi qu’à la prédation grandement accrue des caribous par les loups (Canis lupus). Le retard à détecter ce déclin et le manque de compréhension de ses causes pourront nuire à l’élaboration d’un plan de récupération solide du point de vue écologique. Puisque les déclins précédents de caribous ont été suivis de récupération, on peut se consoler en se disant qu’il est possible que la récupération se fasse spontanément. Cependant, le nombre de caribous a chuté au point où la récupération sera longue et difficile, même dans le meilleur des cas. Il se peut qu’il n’y ait pas de récupération spontanée et par conséquent, on ne devrait pas se contenter de cette situation, surtout puisque l’extirpation des quelques caribous qui restent pourrait éliminer un groupe génétique distinct et réduire la biodiversité du caribou dans l’archipel Arctique canadien
Genetically similar temperate phages form coalitions with their shared host that lead to niche-specific fitness effects.
Temperate phages engage in long-term associations with their hosts that may lead to mutually beneficial interactions, of which the full extent is presently unknown. Here, we describe an environmentally relevant model system with a single host, a species of the Roseobacter clade of marine bacteria, and two genetically similar phages (ɸ-A and ɸ-D). Superinfection of a ɸ-D lysogenized strain (CB-D) with ɸ-A particles resulted in a lytic infection, prophage induction, and conversion of a subset of the host population, leading to isolation of a newly ɸ-A lysogenized strain (CB-A). Phenotypic differences, predicted to result from divergent lysogenic-lytic switch mechanisms, are evident between these lysogens, with CB-A displaying a higher incidence of spontaneous induction. Doubling times of CB-D and CB-A in liquid culture are 75 and 100 min, respectively. As cell cultures enter stationary phase, CB-A viable counts are half of CB-D. Consistent with prior evidence that cell lysis enhances biofilm formation, CB-A produces twice as much biofilm biomass as CB-D. As strains are susceptible to infection by the opposing phage type, co-culture competitions were performed to test fitness effects. When grown planktonically, CB-A outcompeted CB-D three to one. Yet, during biofilm growth, CB-D outcompeted CB-A three to one. These results suggest that genetically similar phages can have divergent influence on the competitiveness of their shared hosts in distinct environmental niches, possibly due to a complex form of phage-mediated allelopathy. These findings have implications for enhanced understanding of the eco-evolutionary dynamics of host-phage interactions that are pervasive in all ecosystems.publishedVersio
Grazing on Marine Viruses and Its Biogeochemical Implications
Viruses are the most abundant biological entities in the ocean and show great diversity in terms of size, host specificity, and infection cycle. Lytic viruses induce host cell lysis to release their progeny and thereby redirect nutrients from higher to lower trophic levels. Studies continue to show that marine viruses can be ingested by nonhost organisms. However, not much is known about the role of viral particles as a nutrient source and whether they possess a nutritional value to the grazing organisms. This review seeks to assess the elemental composition and biogeochemical relevance of marine viruses, including roseophages, which are a highly abundant group of bacteriophages in the marine environment. We place a particular emphasis on the phylum Nucleocytoviricota (NCV) (formerly known as nucleocytoplasmic large DNA viruses [NCLDVs]), which comprises some of the largest viral particles in the marine plankton that are well in the size range of prey for marine grazers. Many NCVs contain lipid membranes in their capsid that are rich carbon and energy sources, which further increases their nutritional value. Marine viruses may thus be an important nutritional component of the marine plankton, which can be reintegrated into the classical food web by nonhost organism grazing, a process that we coin the “viral sweep.” Possibilities for future research to resolve this process are highlighted and discussed in light of current technological advancements.publishedVersio
Parent education interventions designed to support the transition to parenthood: A realist review
AbstractBackgroundPublic health nurses use parent education programmes to support individuals’ transition to parenthood. A wide array of these programmes exists; however, the approach must be accommodated by resources available in a publicly funded system. For example, some new-parent education approaches use 1:1 home visiting (with a nurse or trained lay-home visitor) but the costs of this intensive approach can be prohibitive. Because of this limitation there is an interest in identifying effective and efficient new parent educational approaches that can realistically be provided at a universal level. Unfortunately, there is a lack of high-quality evaluation identifying programmes or educational processes that meet these criteria.ObjectivesTo identify potentially effective new-parenting education interventions that could be implemented at a population level during the transition to parenthood period.DesignRealist synthesis.Data sourcesMedline, CINAHL, ERIC, PsycINFO, Sociological Abstracts, grey literature.Review methodsA realist review method generated a total of 72 papers that were used to inform the results. A three-pronged approach was used incorporating an initial search (6), a database search using applicable keywords and MeSH headings (58), and review of literature identified by advisory group (8 grey literature). An ‘implementation chain’ was developed to outline the overall logic and process behind parent education interventions and to guide the analysis.ResultsSeventy-two papers informed this review: 13 systematic reviews/meta-analyses, 34 intervention studies, 9 opinion papers, 8 programme reviews, and 8 grey literature reports. There was no compelling evidence to suggest that a single educational programme or delivery format was effective at a universal level. Some inherent issues were identified. For example, adult learning principles were overlooked and theories of parent–child interaction were not in evidence. No direct links between universal new-parent education programmes and child development outcomes were established. Programme reach and attrition were key challenges. Programme evaluation criteria were inconsistent, with an over-reliance on parent satisfaction or self-reported intention to change behaviour. There was evidence that effective facilitators helped increase parents’ perceived satisfaction with programmes.ConclusionsIt is unlikely that a single standardized format or programme will meet all the specific learning needs of parents. Multiple approaches that will allow people to access information or education at a time and in a format that suits them may be of value. The importance of the transition to parenthood and its impact on parent and child wellbeing warrant careful consideration of current programming and careful evaluation of future initiatives
Identifying patients at risk for myasthenic crisis with hemogram and inflammation-related laboratory parameters – a pilot study
Background: Myasthenia gravis (MG) is a rare autoimmune disease characterized by fatigable weakness of the voluntary muscles and can exacerbate to life-threatening myasthenic crisis (MC), requiring intensive care treatment. Routine laboratory parameters are a cost-effective and widely available method for estimating the clinical outcomes of several diseases, but so far, such parameters have not been established to detect disease progression in MG. Methods: We conducted a retrospective analysis of selected laboratory parameters related to inflammation and hemogram for MG patients with MC compared to MG patients without MC. To identify potential risk factors for MC, we applied time-varying Cox regression for time to MC and, as a sensitivity analysis, generalized estimating equations logistic regression for the occurrence of MC at the next patient visit. Results: 15 of the 58 examined MG patients suffered at least one MC. There was no notable difference in the occurrence of MC by antibody status or sex. Both regression models showed that higher counts of basophils (per 0.01 unit increase: HR = 1.32, 95% CI = 1.02–1.70), neutrophils (per 1 unit increase: HR = 1.40, 95% CI = 1.14–1.72), potentially leukocytes (per 1 unit increase: HR = 1.15, 95% CI = 0.99–1.34), and platelets (per 100 units increase: HR = 1.54, 95% CI = 0.99–2.38) may indicate increased risk for a myasthenic crisis. Conclusion: This pilot study provides proof of the concept that increased counts of basophils, neutrophils, leukocytes, and platelets may be associated with a higher risk of developing MC in patients with MG
Fc-γ receptor-mediated crosslinking co-defines the immunostimulatory activity of anti-human CD96 antibodies.
New strategies that augment T-cell responses are required to broaden the therapeutic arsenal against cancer. CD96, TIGIT and CD226 are receptors that bind to a communal ligand, CD155, and transduce either inhibitory or activating signals. Whereas the function of TIGIT and CD226 is established, the role of CD96 remains ambiguous. Using a panel of engineered antibodies, we discovered that the T-cell stimulatory activity of anti-CD96 antibodies requires antibody crosslinking and is potentiated by Fc-gamma receptors. Thus, soluble 'Fc silent' anti-CD96 antibodies failed to stimulate human T cells, whereas the same antibodies were stimulatory after coating onto plastic surfaces. Remarkably, the activity of soluble anti-CD96 antibodies was reinstated by engineering the Fc domain to a human IgG1 isotype and was dependent on antibody trans-crosslinking by Fc-γRI. In contrast, neither human IgG2 nor variants with increased Fc-γ receptor IIB binding possessed stimulatory activity. Anti-CD96 antibodies acted directly on T cells and augmented gene expression networks associated with T-cell activation, leading to proliferation, cytokine secretion and resistance to regulatory T-cell suppression. Furthermore, CD96 expression correlated with survival in HPV+ head and neck squamous cell carcinoma and its crosslinking activated tumor-infiltrating T cells, thus highlighting the potential of anti-CD96 antibodies in cancer immunotherapy.
Hypoxia regulates glutamate receptor trafficking through an HIF‐independent mechanism
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102065/1/embj2011499-reviewer_comments.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102065/2/embj2011499-sup-0001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102065/3/embj2011499.pd
Impaired Embryonic Development in Mice Overexpressing the RNA-Binding Protein TIAR
TIA-1-related (TIAR) protein is a shuttling RNA-binding protein involved in several steps of RNA metabolism. While in the nucleus TIAR participates to alternative splicing events, in the cytoplasm TIAR acts as a translational repressor on specific transcripts such as those containing AU-Rich Elements (AREs). Due to its ability to assemble abortive pre-initiation complexes coalescing into cytoplasmic granules called stress granules, TIAR is also involved in the general translational arrest observed in cells exposed to environmental stress. However, the in vivo role of this protein has not been studied so far mainly due to severe embryonic lethality upon tiar invalidation.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe
Nurse forecasting in Europe (RN4CAST): Rationale, design and methodology
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97171.pdf (postprint version ) (Open Access)BACKGROUND: Current human resources planning models in nursing are unreliable and ineffective as they consider volumes, but ignore effects on quality in patient care. The project RN4CAST aims innovative forecasting methods by addressing not only volumes, but quality of nursing staff as well as quality of patient care. METHODS/DESIGN: A multi-country, multilevel cross-sectional design is used to obtain important unmeasured factors in forecasting models including how features of hospital work environments impact on nurse recruitment, retention and patient outcomes. In each of the 12 participating European countries, at least 30 general acute hospitals were sampled. Data are gathered via four data sources (nurse, patient and organizational surveys and via routinely collected hospital discharge data). All staff nurses of a random selection of medical and surgical units (at least 2 per hospital) were surveyed. The nurse survey has the purpose to measure the experiences of nurses on their job (e.g. job satisfaction, burnout) as well as to allow the creation of aggregated hospital level measures of staffing and working conditions. The patient survey is organized in a sub-sample of countries and hospitals using a one-day census approach to measure the patient experiences with medical and nursing care. In addition to conducting a patient survey, hospital discharge abstract datasets will be used to calculate additional patient outcomes like in-hospital mortality and failure-to-rescue. Via the organizational survey, information about the organizational profile (e.g. bed size, types of technology available, teaching status) is collected to control the analyses for institutional differences.This information will be linked via common identifiers and the relationships between different aspects of the nursing work environment and patient and nurse outcomes will be studied by using multilevel regression type analyses. These results will be used to simulate the impact of changing different aspects of the nursing work environment on quality of care and satisfaction of the nursing workforce. DISCUSSION: RN4CAST is one of the largest nurse workforce studies ever conducted in Europe, will add to accuracy of forecasting models and generate new approaches to more effective management of nursing resources in Europe
Pangolins in global camera trap data: Implications for ecological monitoring
Despite being heavily exploited, pangolins (Pholidota: Manidae) have been subject to limited research, resulting in a lack of reliable population estimates and standardised survey methods for the eight extant species. Camera trapping represents a unique opportunity for broad-scale collaborative species monitoring due to its largely non-discriminatory nature, which creates considerable volumes of data on a relatively wide range of species. This has the potential to shed light on the ecology of rare, cryptic and understudied taxa, with implications for conservation decision-making. We undertook a global analysis of available pangolin data from camera trapping studies across their range in Africa and Asia. Our aims were (1) to assess the utility of existing camera trapping efforts as a method for monitoring pangolin populations, and (2) to gain insights into the distribution and ecology of pangolins. We analysed data collated from 103 camera trap surveys undertaken across 22 countries that fell within the range of seven of the eight pangolin species, which yielded more than half a million trap nights and 888 pangolin encounters. We ran occupancy analyses on three species (Sunda pangolin Manis javanica, white-bellied pangolin Phataginus tricuspis and giant pangolin Smutsia gigantea). Detection probabilities varied with forest cover and levels of human influence for P. tricuspis, but were low (<0.05) for all species. Occupancy was associated with distance from rivers for M. javanica and S. gigantea, elevation for P. tricuspis and S. gigantea, forest cover for P. tricuspis and protected area status for M. javanica and P. tricuspis. We conclude that camera traps are suitable for the detection of pangolins and large-scale assessment of their distributions. However, the trapping effort required to monitor populations at any given study site using existing methods appears prohibitively high. This may change in the future should anticipated technological and methodological advances in camera trapping facilitate greater sampling efforts and/or higher probabilities of detection. In particular, targeted camera placement for pangolins is likely to make pangolin monitoring more feasible with moderate sampling efforts
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