2,606 research outputs found

    A CFD-based Approach to Predict Explosion Overpressure: A Comparison to Current Methods

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    A CFD-based approach has been developed in this work to predict the overpressure produced during an explosion. An adiabatic exothermal reaction allows computing the explosion energy release. To validate the proposed CFD approach, overpressure predictions based on this methodology are compared with results produced with the TNObased method. It is demonstrated that the physics adopted in our model produces satisfactory predictions in the open area. The CFD simulations were carried out in the ANSYS CFX tool. The source of energy corresponds to the one produced by a stoichiometric proportion in reactants without energy generation. The explosion analysis considered that explosion occurs geometrically as a sequence of control volumes. Thus, the explosion in a volume is assumed to occur when the maximum pressure is achieved in the previous control volume. This way, the explosion is propagated and it is shown that it is equivalent to conventional predicting methods

    The role of fungi in the cocoa production chain and the challenge of climate change

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    Background: The role of fungi in cocoa crops is mainly associated with plant diseases and contamination of harvest with unwanted metabolites such as mycotoxins that can reach the final consumer. However, in recent years there has been interest in discovering other existing interactions in the environment that may be beneficial, such as antagonism, commensalism, and the production of specific enzymes, among others. Scope and approach: This review summarizes the different fungi species involved in cocoa production and the cocoa supply chain. In particular, it examines the presence of fungal species during cultivation, harvest, fermentation, drying, and storage, emphasizing the factors that possibly influence their prevalence in the different stages of production and the health risks associated with the production of mycotoxins in the light of recent literature. Key find-ings and conclusion: Fungi associated with the cocoa production chain have many different roles. They have evolved in a varied range of ecosystems in close association with plants and various habitats, affecting nearly all the cocoa chain steps. Reports of the isolation of 60 genera of fungi were found, of which only 19 were involved in several stages. Although endophytic fungi can help control some diseases caused by pathogenic fungi, climate change, with increased rain and tempera-tures, together with intensified exchanges, can favour most of these fungal infections, and the presence of highly aggressive new fungal genotypes increasing the concern of mycotoxin production. For this reason, mitigation strategies need to be determined to prevent the spread of disease-causing fungi and preserve beneficial ones

    Characterization, conservation and loss of dignity at the end-of- life in the emergency department. A qualitative protocol

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    Aims: to explore and understand the experiences of terminally-ill patients and their relatives regarding dignity during end-of-life care in the emergency department. Background: the respect given to the concept of dignity is significantly modifying the clinical relationship and the care framework involving the end-of-life patient in palliative care units, critical care units, hospices and their own homes. This situation is applicable to in-hospital emergency departments, where there is a lack of research which takes the experiences of end-of-life patients and their relatives into account. Design: a phenomenological qualitative study. Methods: the protocol was approved in December 2016 and will be carried out from December 2016 to December 2020. The Gadamer's philosophical underpinnings will be used in the design and development of the study. The data collection will include participant observation techniques in the Emergency Department, in-depth interviews with terminally-ill patients and focus groups with their relatives. For the data analysis, the field notes and verbatim transcriptions will be read and codified using ATLAS.ti software to search for emerging themes. Discussion: emerging themes that contribute to comprehending the phenomenon of dignity in end-of-life care in the Emergency Department are expected to be found. This study's results could have important implications in the implementation of new interventions in Emergency Departments. These interventions would be focused on improving: the social acceptance of death, environmental conditions, promotion of autonomy and accompaniment, and assumption (takeover) of dignified actions and attitudes (respect for human rights)

    A Novel Stochastic Multi-Scale Model of Francisella tularensis Infection to Predict Risk of Infection in a Laboratory

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    We present a multi-scale model of the within-phagocyte, within-host and population-level infection dynamics of Francisella tularensis, which extends the mechanistic one proposed by Wood et al. (2014). Our multi-scale model incorporates key aspects of the interaction between host phagocytes and extracellular bacteria, accounts for inter-phagocyte variability in the number of bacteria released upon phagocyte rupture, and allows one to compute the probability of response, and mean time until response, of an infected individual as a function of the initial infection dose. A Bayesian approach is applied to parameterize both the within-phagocyte and within-host models using infection data. Finally, we show how dose response probabilities at the individual level can be used to estimate the airborne propagation of Francisella tularensis in indoor settings (such as a microbiology laboratory) at the population level, by means of a deterministic zonal ventilation model

    Fundamental care and knowledge interests: implications for nursing science

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    Aims and objectives: The aim of this discursive paper was to characterize the intra-theoretical interests of knowledge in nursing science as an epistemological framework for fundamental care. Background: For Jürgen Habermas, theory does not separate knowledge interests from life. All knowledge, understanding and human research is always interested. Habermas formulated the knowledge interests in empirical-analytical, historical hermeneutic and critical social sciences; but said nothing about health sciences and nursing science. Design: Discursive paper. Results: The paper is organised into five sections that develop our argument about the implications of the Habermasian intra theoretical interests in nursing science and fundamental care: the persistence of a technical interest, the predominance of a practical interest, the importance of an emancipatory interest, “being there” to understand individuals’ experience and an “existential crisis” that uncovers the individual’s subjectivity. Conclusions: The nursing discipline can take on practical and emancipatory interests (together with a technical interest) as its fundamental knowledge interests. Nurses’ privileged position in the delivery of fundamental care gives them the opportunity to gain a deep understanding of the patient’s experience and illness process through physical contact and empathic communication. Relevance to clinical practice and nursing research: In clinical, academic and research environments, nurses should highlight the importance of fundamental care, showcasing the value of practical and emancipatory knowledge. This process could help to improve nursing science’s leadership, social visibility and idiosyncrasy

    Sexuality throughout all the stages of pregnancy: experiences of expectant mothers

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    Objective: To explore and understand the sexual experiences of expectant mothers during their pregnancy. Methods: The study was carried out in two healthcare centers in the Almería Health District, in southern Spain. The participants included pregnant women who received prenatal care and/or maternity education. The inclusion criteria were being pregnant, maintaining sexual activity and agreeing to participate in the study. The exclusion criteria were having limitations on sexual activity by medical prescription. The sample consisted of 15 expectant women selected using a convenience sample, of which 5 took part in a focus group (FG) and 10 in in-depth interviews (IDI). Data was collected between the months of June and December 2016. Participants were contacted by the main researcher and an appointment was made to carry out the FGs or the IDIs. Results: Three main categories emerged: False beliefs and a holistic approach to sexuality during pregnancy, which is related to the concept of sexuality, false beliefs, and limited sexual counseling during pregnancy. Limitations: From fear at the beginning to physical diffi culty at the end, referring to the fluctuations in sexual desire as well as the physical changes that limit sexual activity. Adapting to changes: safe practices and satisfaction with one’s body image, which encompasses concerns about the risks and the relationship between body image and self-esteem. Conclusion: A lack of sexual counseling during pregnancy leads to the creation of false beliefs, which, together with physical changes, concerns about the risk, and fl uctuations in sexual desire and interest, bring about a decrease in sexual activity. But sexuality remains an important aspect of pregnancy, toward which the participants must adopt a broader approach, not limited to intercourse, and adopt sexual practices that are adapted to the physical and emotional changes that happen during this time

    Accompanied child irregular migrants who arrive to Spain in small boats: experiences and health needs

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    The European Union is the preferred destination of child irregular migrants arrived from northern Africa, who risk their lives crossing the Mediterranean Sea in small boats. Accompanied Child Irregular Migrants (AChIMs) are exposed to physical and psychological risk. The objective of our study is to describe and understand the experiences and health needs of AChIMs who arrive to Spain in small boats, through the testimony of adults who accompany them on the journey. A qualitative study, based on Gadamer's hermeneutic phenomenology, was performed. After obtaining approval from the Ethics and Research Committee, we conducted in-depth interviews on 32 adults who travelled with AChIMs. Two main themes emerged: (1) The journey a child should never have to take, with the subthemes 'AChIMs as a paradigm of vulnerability' and 'Crossing the sea, playing with death' and (2) Characterising emergency care to AChIMs, with the subthemes 'Prioritising specific care', 'Identifying high-risk situations' and 'The detaining of innocent children'. AChIMs, along with adults, risk their lives in such a dangerous and perilous journey, therefore, finding out about their experiences may contribute to improving the treatment of their specific health needs during the phases of rescue and emergency care

    Stochastic dynamics of Francisella tularensis infection and replication

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    We study the pathogenesis of Francisella tularensis infection with an experimental mouse model, agent-based computation and mathematical analysis. Following inhalational exposure to Francisella tularensis SCHU S4, a small initial number of bacteria enter lung host cells and proliferate inside them, eventually destroying the host cell and releasing numerous copies that infect other cells. Our analysis of disease progression is based on a stochastic model of a population of infectious agents inside one host cell, extending the birth-and-death process by the occurrence of catastrophes: cell rupture events that affect all bacteria in a cell simultaneously. Closed expressions are obtained for the survival function of an infected cell, the number of bacteria released as a function of time after infection, and the total bacterial load. We compare our mathematical analysis with the results of agent-based computation and, making use of approximate Bayesian statistical inference, with experimental measurements carried out after murine aerosol infection with the virulent SCHU S4 strain of the bacterium Francisella tularensis, that infects alveolar macrophages. The posterior distribution of the rate of replication of intracellular bacteria is consistent with the estimate that the time between rounds of bacterial division is less than 6 hours in vivo

    Vortex solitons of the discrete Ginzburg-Landau Equation

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    We have found several families of vortex soliton solutions in two-dimensional discrete dissipative systems governed by the cubic-quintic complex Ginzburg-Landau equation. There are symmetric and asymmetric solutions, and some of them have simultaneously two different topological charges. Their regions of existence and stability are determined. Additionally, we have analyzed the relation- ship between dissipation and stability for a number of solutions. We have obtained that dissipation favours the stability of the solutions.Comment: 7 pages, 11 figure
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