435 research outputs found

    Interactions with soil fungi alter density dependence and neighborhood effects in a locally abundant dipterocarp species

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    Seedling recruitment can be strongly affected by the composition of nearby plant species. At the neighborhood scale (on the order of tens of meters), adult conspecifics can modify soil chemistry and the presence of host microbes (pathogens and mutualists) across their combined canopy area or rooting zones. At local or small spatial scales (on the order of one to few meters), conspecific seed or seedling density can influence the strength of intraspecific light and resource competition and also modify the density-dependent spread of natural enemies such as pathogens or invertebrate predators. Intrinsic correlation between proximity to adult conspecifics (i.e., recruitment neighborhood) and local seedling density, arising from dispersal, makes it difficult to separate the independent and interactive factors that contribute to recruitment success. Here, we present a field experiment in which we manipulated both the recruitment neighborhood and seedling density to explore how they interact to influence the growth and survival of Dryobalanops aromatica, a dominant ectomycorrhizal tree species in a Bornean tropical rainforest. First, we found that both local seedling density and recruitment neighborhood had effects on performance of D. aromaticaseedlings, though the nature of these impacts varied between growth and survival. Second, we did not find strong evidence that the effect of density on seedling survival is dependent on the presence of conspecific adult trees. However, accumulation of mutualistic fungi beneath conspecifics adults does facilitate establishment of D. aromatica seedlings. In total, our results suggest that recruitment near adult conspecifics was not associated with a performance cost and may have weakly benefitted recruiting seedlings. Positive effects of conspecifics may be a factor facilitating the regional hyperabundance of this species. Synthesis: Our results provide support for the idea that dominant species in diverse forests may escape the localized recruitment suppression that limits abundance in rarer species

    Dominance, reproductive behaviours and female mate choice in sterilised versus non-sterilised invasive male crayfish

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    © 2020, The Author(s). Many methods of controlling invasive crayfishes have limited success because they fail to target all life stages of the population, notably by capturing only large adults that can result in increased juvenile recruitment by removing intraspecific predation. An alternative approach uses the sterile male release technique that involves the mass release of sterile males into the environment, which then mate with fertile females, resulting in unfertilised eggs and, ultimately, reduced juvenile recruitment. This does, however, rely on the sterilised males exhibiting behaviours similar to non-sterilised (entire) males and remaining attractive to females during mate choice. Post-copulatory male guarding behaviour and female promiscuity might also be affected by male sterilisation. To test for the presence of normal reproductive behaviours in sterilised male American signal crayfish Pacifastacus leniusculus, a two-stage experiment examined how sterilisation affects female mate choice and promiscuity, male hierarchical status (relative dominance) and post-copulation guarding. Sterilised males showed similar reproductive behaviours to entire males and remained as attractive to females, with no differences in relative dominance. Post-copulation, guarding behaviours were also unaffected. Females did not display promiscuous behaviour and this was unaffected by whether males were entire or sterilised. The results demonstrated that sterilised males were equally as capable as entire males of achieving dominance and winning mates. In combination, these findings suggest that male sterilisation could be an effective control technique to help reduce juvenile recruitment in wild P. leniusculus populations by reducing reproductive success

    Life After Succession in the Family Business: Is It Really the End of Problems?

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    The succession processes in family business are well chronicled in the business literature. Most of the research focuses on the process of transferring power within the business-family. What has not been as closely examined is the after-succession environment that exists when the management and leadership of the family business are passed on to the next generation. This article addresses that organizational climate and the potential for additional problems in the business-family if post-succession issues are not identified and addressed and suggests some steps that will be helpful in producing complete succession success.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Necessary connections: ‘Feelings photographs’ in criminal justice research

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    Visual representations of prisons and their inmates are common in the news and social media, with stories about riots, squalor, drugs, self-harm and suicide hitting the headlines. Prisoners’ families are left to worry about the implications of such events on their kin, while those incarcerated and less able to understand social cues, norms and rules, are vulnerable to deteriorating mental health at best, to death at worst. As part of the life-story method in my research with offenders who are on the autism spectrum, have mental health problems and/or have learning difficulties, and prisoner’s mothers, I asked participants to take photographs, reflecting upon their experiences. Photographs in this case, were primarily used to help respondents consider and articulate their feelings in follow-up interviews. Notably, seeing (and imagining) is often how we make a connection to something (object or feeling), or someone (relationships), such that images in fiction, news/social media, drama, art, film and photographs can shape the way people think and behave – indeed feel about things and people. Images and representations ought to be taken seriously in researching social life, as how we interpret photographs, paintings, stories and television shows is based on our own imaginings, biography, culture and history. Therefore, we look at and process an image before words escape, by ‘seeing’ and imagining. How my participants and I ‘collaborate’ in doing visual methods and then how we make meaning of the photographs in storying their feelings, is insightful. As it is, I wanted to enable my participants to make and create their own stories via their photographs and narratives, whilst connecting to them, along with my own interpretation and subjectivities

    Implementation of an evidence-based guideline on fluid resuscitation: lessons learnt for future guidelines

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    There is little experience with the nationwide implementation of an evidence-based pediatric guideline on first-choice fluid for resuscitation in hypovolemia. We investigated fluid prescribing behavior at (1) guideline development, (2) after guideline development, and (3) after active implementation and identified potential barriers and facilitators for guideline implementation. In order to minimize costs and to optimize implementation effect, we continuously developed and adjusted implementation strategies according to identified barriers. Implementation success was evaluated using questionnaires, pharmaceutical data, and data from medical records. The most remarkable change occurred after guideline development and dissemination: Normal saline use by neonatologists increased from 22-89% to 100% and by pediatric intensivists from 43-71% to 88-100%, and synthetic colloid use by pediatric intensivists declined from 29-43% to 0-13% with a reduction in albumin use by neonatologists from 11-44% to 0%. After active guideline implementation, most of specialist's management behavior was according to the guideline. Stakeholders involved in the developmental process are of great importance in disseminating recommendations before active implementation. Therefore, to successfully implement guidelines and reduce costs of active implementation, any guideline development should consider implementation right from the beginning. Implementation strategies should target identified barriers and will therefore always be guideline specifi

    Integrating Teaching and Research in Undergraduate Biology Laboratory Education

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    A course recently designed and implemented at Stanford University applies practical suggestions for creating research-based undergraduate courses that benefit both teaching and research

    Not poles apart: Antarctic soil fungal communities show similarities to those of the distant Arctic

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    Antarctica's extreme environment and geographical isolation offers a useful platform for testing the relative roles of environmental selection and dispersal barriers influencing fungal communities. The former process should lead to convergence in community composition with other cold environments, such as those in the Arctic. Alternatively, dispersal limitations should minimise similarity between Antarctica and distant northern landmasses. Using high-throughput sequencing, we show that Antarctica shares significantly more fungi with the Arctic, and more fungi display a bipolar distribution, than would be expected in the absence of environmental filtering. In contrast to temperate and tropical regions, there is relatively little endemism, and a strongly bimodal distribution of range sizes. Increasing southerly latitude is associated with lower endemism and communities increasingly dominated by fungi with widespread ranges. These results suggest that micro-organisms with well-developed dispersal capabilities can inhabit opposite poles of the Earth, and dominate extreme environments over specialised local specie

    No More Free Drug Samples?

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    Susan Chimonas and Jerome Kassirer argue that giving out “free” drug samples is not effective in improving drug access for the indigent, does not promote rational drug use, and raises the cost of care
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