668 research outputs found

    Conflict Prevention and Separation Assurance Method in the Small Aircraft Transportation System

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    A multilayer approach to the prevention of conflicts due to the loss of aircraft-to-aircraft separation which relies on procedures and on-board automation was implemented as part of the SATS HVO Concept of Operations. The multilayer system gives pilots support and guidance during the execution of normal operations and advance warning for procedure deviations or off-nominal operations. This paper describes the major concept elements of this multilayer approach to separation assurance and conflict prevention and provides the rationale for its design. All the algorithms and functionality described in this paper have been implemented in an aircraft simulation in the NASA Langley Research Center s Air Traffic Operation Lab and on the NASA Cirrus SR22 research aircraft

    Pairwise Trajectory Management (PTM): Concept Description and Documentation

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    Pairwise Trajectory Management (PTM) is an Interval Management (IM) concept that utilizes airborne and ground-based capabilities to enable the implementation of airborne pairwise spacing capabilities in oceanic regions. The goal of PTM is to use airborne surveillance and tools to manage an "at or greater than" inter-aircraft spacing. Due to the accuracy of Automatic Dependent Surveillance-Broadcast (ADS-B) information and the use of airborne spacing guidance, the minimum PTM spacing distance will be less than distances a controller can support with current automation systems that support oceanic operations. Ground tools assist the controller in evaluating the traffic picture and determining appropriate PTM clearances to be issued. Avionics systems provide guidance information that allows the flight crew to conform to the PTM clearance issued by the controller. The combination of a reduced minimum distance and airborne spacing management will increase the capacity and efficiency of aircraft operations at a given altitude or volume of airspace. This document provides an overview of the proposed application, a description of several key scenarios, a high level discussion of expected air and ground equipment and procedure changes, a description of a NASA human-machine interface (HMI) prototype for the flight crew that would support PTM operations, and initial benefits analysis results. Additionally, included as appendices, are the following documents: the PTM Operational Services and Environment Definition (OSED) document and a companion "Future Considerations for the Pairwise Trajectory Management (PTM) Concept: Potential Future Updates for the PTM OSED" paper, a detailed description of the PTM algorithm and PTM Limit Mach rules, initial PTM safety requirements and safety assessment documents, a detailed description of the design, development, and initial evaluations of the proposed flight crew HMI, an overview of the methodology and results of PTM pilot training requirements focus group and human-in-the-loop testing activities, and the PTM Pilot Guide

    Pairwise Trajectory Management (PTM): Concept Overview

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    Pairwise Trajectory Management (PTM) is an Interval Management (IM) concept that utilizes airborne and ground-based capabilities to enable the implementation of airborne pairwise spacing capabilities in oceanic regions. The goal of PTM is to use airborne surveillance and tools to manage an "at or greater than" inter-aircraft spacing. Due to the precision of Automatic Dependent Surveillance-Broadcast (ADS-B) information and the use of airborne spacing guidance, the PTM minimum spacing distance will be less than distances a controller can support with current automation systems that support oceanic operations. Ground tools assist the controller in evaluating the traffic picture and determining appropriate PTM clearances to be issued. Avionics systems provide guidance information that allows the flight crew to conform to the PTM clearance issued by the controller. The combination of a reduced minimum distance and airborne spacing management will increase the capacity and efficiency of aircraft operations at a given altitude or volume of airspace. This paper provides an overview of the proposed application, description of a few key scenarios, high level discussion of expected air and ground equipment and procedure changes, overview of a potential flight crew human-machine interface that would support PTM operations and some initial PTM benefits results

    Detection of protection benefits for predatory fishes depends on census methodology

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    Marine protected areas (MPAs) are used as fisheries management and conservation tools. Well-enforced no-take zones allow the rebuilding of natural populations of exploited species; however, there is still controversy on the role of buffer zones. The effectiveness of MPAs could be underestimated, as fish population assessments depend largely on traditional methodologies that have difficulties in detecting predatory fish because of their low abundances, their patchy distribution, and their reaction to the presence of divers. The performance of different census methods was compared in assessing the protection benefits for large predatory fishes under different protection levels (i.e. no-take and buffer zones) in five Mediterranean MPAs. Specifically, conventional strip transects (CSTs, 50 × 5 m2) and tracked roaming transects combined with distance sampling (TRT + DS, variable lengths) were compared, including a series of TRT-derived estimators with variable transect lengths and fixed widths of 20, 10, and 6 m (TRT20, TRT10, and TRT6, respectively). Additionally, the effectiveness of the MPAs studied and protection levels for conserving large predatory species was evaluated. Transects covering larger areas (i.e. TRT + DS and TRT20) allowed the detection of a greater number of species and yielded more accurate estimates of density and biomass than transects of narrower fixed widths, particularly the CSTs, which were associated with the lowest richness detection capability, accuracy, and precision. On average, both no-take zones and buffer zones appeared effective for the conservation of predatory fishes, indicating that multiple protection areas were ecologically effective. Differences between MPAs were also observed, however, probably arising from both local environmental and management factors. We suggest the implementation of methodologies with larger transects for the study of large predatory fish, combined with CSTs for the rest of the fish community, in order to avoid biases in predatory population assessments, which are key indicators of MPA effectiveness

    Major Allergen Content in Allergen Immunotherapy Products: The Limited Value of Numbers

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    The prevalence of allergic disorders has increased drastically over the last 50 years to the extent that they can be considered epidemic. At present, allergen-specific immunotherapy (AIT) is the only therapy that targets the underlying cause of allergic disorders, and evidence of its superiority is based on data accumulated from clinical trials and observational studies demonstrating efficacy and safety. However, several aspects remain unresolved, such as harmonization and standardization of manufacturing and quantification procedures across manufacturers, homogeneous reporting of strength, and the establishment of international reference standards for many allergens. This article discusses issues related to the measurement of major allergen content in AIT extracts, raising the question of whether comparison of products from different manufacturers is an appropriate basis for selecting a specific AIT product. Allergen standardization in immunotherapy products is critical for ensuring quality and, thereby, safety and efficacy. However, lack of harmonization in manufacturing processes, allergen quantification (methodologies and references), national regulatory differences, clinical practice, and labeling shows that the comparison of AIT products based solely on major allergen amounts is not rational and, in fact, impossible. Moreover, when rating the information given for a specific product, it is necessary to take into account further inherent characteristics of products and their application in clinical practice, such as the state of extract modification, addition of adjuvant or adjuvant system, route of administration (sublingual/ subcutaneous), and cumulative dose as per posology (including the volume per administration). Finally, only convincing clinical data can serve as the basis for product-specific evaluation and cross-product comparability of individual products

    Diurnal Differences in Intracellular Replication Within Splenic Macrophages Correlates With the Outcome of Pneumococcal Infection

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    Circadian rhythms affect the progression and severity of bacterial infections including those caused by Streptococcus pneumoniae, but the mechanisms responsible for this phenomenon remain largely elusive. Following advances in our understanding of the role of replication of S. pneumoniae within splenic macrophages, we sought to investigate whether events within the spleen correlate with differential outcomes of invasive pneumococcal infection. Utilising murine invasive pneumococcal disease (IPD) models, here we report that infection during the murine active phase (zeitgeber time 15; 15h after start of light cycle, 3h after start of dark cycle) resulted in significantly faster onset of septicaemia compared to rest phase (zeitgeber time 3; 3h after start of light cycle) infection. This correlated with significantly higher pneumococcal burden within the spleen of active phase-infected mice at early time points compared to rest phase-infected mice. Whole-section confocal microscopy analysis of these spleens revealed that the number of pneumococci is significantly higher exclusively within marginal zone metallophilic macrophages (MMMs) known to allow intracellular pneumococcal replication as a prerequisite step to the onset of septicaemia. Pneumococcal clusters within MMMs were more abundant and increased in size over time in active phase-infected mice compared to those in rest phase-infected mice which decreased in size and were present in a lower percentage of MMMs. This phenomenon preceded significantly higher levels of bacteraemia alongside serum IL-6 and TNF-alpha concentrations in active phase-infected mice following re-seeding of pneumococci into the blood. These data greatly advance our fundamental knowledge of pneumococcal infection by linking susceptibility to invasive pneumococcal infection to variation in the propensity of MMMs to allow persistence and replication of phagocytosed bacteria. These findings also outline a somewhat rare scenario whereby the active phase of an organism's circadian cycle plays a seemingly counterproductive role in the control of invasive infection

    Perceções dos enfermeiros sobre os erros de medicação no pré-hospitalar

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    Quase metade da totalidade de eventos adversos evitáveis é consequência de erros de medicação (EM), contudo, não sendo possível evitá-los completamente, estes podem ser minorados. Esta problemática em contexto pré-hospitalar (PH) tem sido pouco estudada a nível internacional e nunca foi abordada em Portugal. O objetivo deste estudo é relacionar as variáveis sociodemográficas, socioprofissionais, formação, conhecimentos e experiências com EM com a perceção dos enfermeiros que exercem no PH relativamente à frequência da ocorrência dos tipos e causas de EM, dos obstáculos ao relato de EM, dos fatores facilitadores do relato de EM e com o grau de concordância sobre divulgação de EM. Métodos: Trata-se de um estudo analítico, descritivo, transversal e correlacional. A amostra é composta por 107 enfermeiros do PH (método snowball), dos quais 56.1% são do sexo masculino. Foi aplicado um questionário eletrónico constituído por uma componente sociodemográfica, escala de conhecimentos, perceções e experiência com erros de medicação (Raimundo, 2011; Maurer, 2010; Bohomol & Ramos, 2006; Mayo & Duncan, 2004; Osborne, Blais & Hayes, 1999; Gladstone, 1995). Resultados: Dos inquiridos 60.7% apresentam fracos a razoáveis conhecimentos sobre EM; mais de 54% perceciona a sua formação académica/contínua sobre EM como sendo inexistente/insuficiente e 52.3% não recebe formação sobre farmacologia há pelo menos 6 anos; 45.8% diz ter experienciado no PH um ou mais EM sem dano para o doente e apenas 14.9% relatou um ou mais EM sem dano para o doente. Os tipos e as causas de EM identificadas ocorrem com uma frequência elevada para mais de 39% dos inquiridos. A maioria dos inquiridos (47.7%) considera que no PH existem grandes obstáculos ao relato de EM e os fatores facilitadores do relato de EM apresentados são considerados por 49.5% dos enfermeiros como altamente prováveis de facilitar o relato. 52,3% dos enfermeiros do PH discordam de uma forma global com a divulgação de EM. O sexo feminino apresenta uma perceção mais elevada da ocorrência das causas primárias de EM (MF=2.68, Dp= 0.60 vs MM=2.36, Dp=0.66) e uma perceção mais elevada dos fatores facilitadores ao relato dos EM (MF=4.40, Dp= 0.64 vs MM=4.12, Dp=0.74). Os enfermeiros que exercem exclusivamente no PH possuem uma melhor perceção da frequência de ocorrência das causas primárias de EM. Quanto maior o conhecimento dos enfermeiros sobre EM, maior é a perceção destes relativamente aos tipos de erros e maior o grau de concordância com a divulgação dos EM. Existe evidência estatisticamente significativa (p<0.05) de que os enfermeiros que experienciaram a ocorrência de pelo menos 1 erro com dano para o doente possuem melhor perceção dos tipos, causas primárias e obstáculos ao relato dos EM, assim como apresenta um maior grau de concordância com a divulgação de EM. Conclusão: A perceção dos enfermeiros sobre a frequência dos tipos e das causas de EM, assim como dos obstáculos e dos fatores facilitadores do relato de EM por parte dos enfermeiros no PH não tem, de uma forma geral, relação com as características sociodemográficas e socioprofissionais, o que demonstra a transversalidade desta problemática. Tão ou mais importante do que avaliar a dimensão e caracterizar a tipologia, causas, obstáculos e fatores facilitadores ao relato dos EM será, com base no conhecimento obtido, definir e implementar ações de gestão de risco que permitam a sua redução ou mesmo a sua supressão. PALAVRAS-CHAVE: Erros de Medicação, Perceção dos Enfermeiros, Pré- Hospitalar.ABSTRACT Almost half of all preventable adverse events is the result of medication errors (ME), however, it’s not possible to avoid them completely, but they can be mitigated. This problem in the prehospital setting (PH) has been little studied internationally and has never been approached in Portugal. The objective of this study is to relate the socio-demographic, professional, training, knowledge and experience variables with ME, with the PH nurse’s perception of the occurrence frequency of the types and causes of ME, obstacles to the reporting of ME, facilitating factors of ME and with the degree of agreement on the disclosure of ME. Methods: Analytical, descriptive, cross-sectional and correlational study. Sample with 107 PH nurses (snowball method), of which 56.1% are male gender. Application of an electronic survey composed by a socio-demographic component, a knowledge scale on ME and a scale on perceptions and experiences on ME (Raymond, 2011; Maurer, 2010; Bohomol & Ramos, 2006; Mayo & Duncan, 2004; Osborne, Blais & Hayes, 1999 ; Gladstone, 1995). Results: 60.7% of the nurses inquired have a poor or reasonable knowledge about ME; over 54% consider their academic/continuous training on ME as inexistent/insufficient and 52.3% have not had any continuous training on this subject for at least 6 years; 45.8% claim to have experienced one or more PH ME with no damage for the patient and only 14.9% reported one or more reported one or ME without any harm to the patient. The identified types and causes for the ME occur with a high frequency for over 39% of the enquired people. Most respondents (47.7%) consider that in the PH setting there are considerable obstacles to the reporting of ME and the facilitating factors of ME reports presented are considered by 49.5% of the nurses as highly likely to facilitate reporting. 52.3% of the PH nurses disagree with the disclosure of ME. Females have a higher perception of the occurrence of the primary causes of ME (MF = 2.68, SD = 0.60 vs MM = 2.36, SD = 0.66) and a higher perception of the facilitating factors for reporting ME (MF = 4.40, SD = 0.64 vs MM = 4.12 SD = 0.74). Nurses that work exclusively in the PH have a better perception of the frequency of occurrence of the primary causes of ME. The higher nurses' knowledge of ME matches to a higher perception of the types of ME and to a higher degree of agreement with the disclosure of ME. There’s statistically significant evidence (p <0.05) that nurses who experienced the occurrence of at least one error with damage to the patient has better perception of types, primary causes and obstacles to reporting of ME, as well as presents a higher degree of agreement with the disclosure of ME Conclusion: The PH nurses’ perception on the frequency of the types and causes of ME, as well on the obstacles and facilitating factors for ME reporting is generally not related to the socio-demographic and socio-professional characteristics, demonstrating the transversality of this issue. Equally or more important than assessing the extent and characterize the types, causes, obstacles and facilitating factors for reporting ME, will be define and implement risk management actions that allow its reduction or even its suppression, based on the knowledge gained. KEY WORDS: Medication Errors; Nurse’s Perception; Prehospital

    LRCH Proteins: A Novel Family of Cytoskeletal Regulators

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    Background: Comparative genomics has revealed an unexpected level of conservation for gene products across the evolution of animal species. However, the molecular function of only a few proteins has been investigated experimentally, and the role of many animal proteins still remains unknown. Here we report the characterization of a novel family of evolutionary conserved proteins, which display specific features of cytoskeletal scaffolding proteins, referred to as LRCHs. Principal Findings: Taking advantage of the existence of a single LRCH gene in flies, dLRCH, we explored its function in cultured cells, and show that dLRCH act to stabilize the cell cortex during cell division. dLRCH depletion leads to ectopic cortical blebs and alters positioning of the mitotic spindle. We further examined the consequences of dLRCH deletion throughout development and adult life. Although dLRCH is not essential for cell division in vivo, flies lacking dLRCH display a reduced fertility and fitness, particularly when raised at extreme temperatures. Conclusion/Significance: These results support the idea that some cytoskeletal regulators are important to buffer environmental variations and ensure the proper execution of basic cellular processes, such as the control of cell shape

    Low pH immobilizes and kills human leukocytes and prevents transmission of cell-associated HIV in a mouse model

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    BACKGROUND: Both cell-associated and cell-free HIV virions are present in semen and cervical secretions of HIV-infected individuals. Thus, topical microbicides may need to inactivate both cell-associated and cell-free HIV to prevent sexual transmission of HIV/AIDS. To determine if the mild acidity of the healthy vagina and acid buffering microbicides would prevent transmission by HIV-infected leukocytes, we measured the effect of pH on leukocyte motility, viability and intracellular pH and tested the ability of an acidic buffering microbicide (BufferGel(®)) to prevent the transmission of cell-associated HIV in a HuPBL-SCID mouse model. METHODS: Human lymphocyte, monocyte, and macrophage motilities were measured as a function of time and pH using various acidifying agents. Lymphocyte and macrophage motilities were measured using video microscopy. Monocyte motility was measured using video microscopy and chemotactic chambers. Peripheral blood mononuclear cell (PBMC) viability and intracellular pH were determined as a function of time and pH using fluorescent dyes. HuPBL-SCID mice were pretreated with BufferGel, saline, or a control gel and challenged with HIV-1-infected human PBMCs. RESULTS: Progressive motility was completely abolished in all cell types between pH 5.5 and 6.0. Concomitantly, at and below pH 5.5, the intracellular pH of PBMCs dropped precipitously to match the extracellular medium and did not recover. After acidification with hydrochloric acid to pH 4.5 for 60 min, although completely immotile, 58% of PBMCs excluded ethidium homodimer-1 (dead-cell dye). In contrast, when acidified to this pH with BufferGel, a microbicide designed to maintain vaginal acidity in the presence of semen, only 4% excluded dye at 10 min and none excluded dye after 30 min. BufferGel significantly reduced transmission of HIV-1 in HuPBL-SCID mice (1 of 12 infected) compared to saline (12 of 12 infected) and a control gel (5 of 7 infected). CONCLUSION: These results suggest that physiologic or microbicide-induced acid immobilization and killing of infected white blood cells may be effective in preventing sexual transmission of cell-associated HIV
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