261 research outputs found
Human-automation interaction for lunar landing aimpoint redesignation
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2008.Includes bibliographical references (leaves 86-89).Human-automation interactions are a critical area of research in systems with modem automation. The decision-making portion of tasks presents a special challenge for human-automation interactions because of the many factors that play a role in the decision-making process. This is prominent in human spaceflight, where the astronaut must continually interact with the vehicle systems. In future lunar landings, astronauts working in conjunction with automated systems will need to select a safe and achievable landing aimpoint. Ultimately, this decision could risk the safety of the astronauts and the success of their mission. Careful study is needed to ascertain the roles of both the human and the automation and how design can best support the decision making process. The task of landing on the moon was first achieved by the Apollo program in 1969, but technological advances will provide future landings with a greater variety and extensibility of mission goals. The modem task of selecting a landing aimpoint is known as landing point redesignation (LPR), and this work capitalizes on an existing LPR algorithm in order to explore the effects on landing point selection by altering the levels of automation. An experiment was designed to study the decision-making process with three different levels of automation. In addition, the effect of including a human-generated goal that was not captured by the automation was studied. The experimental results showed that the subjects generally used the same decision strategies across the different levels of automation, and that higher levels of automation were able to eliminate earlier parts of the decision strategy and allow the subjects to select a landing aimpoint more quickly. In scenarios with the additional human goal, subjects tended to sacrifice significant safety margins in order to achieve proximity to the point of interest. Higher levels of automation allowed them to maintain high levels of safety margins in addition to achieving their external goal. Thus, it is concluded that with a display design supporting human goals in a decision-making task, automated decision aids that make recommendations and assist communication of the automation's processes are highly beneficial.by Jennifer M. Heedham.S.M
Model-based spacecraft and mission design for the evaluation of technology
In order to meet the future vision of robotic missions, engineers will face intricate mission concepts, new operational approaches, and technologies that have yet to be developed. The concept of smaller, model driven projects helps this transition by including life-cycle cost as part of the decision making process. For example, since planetary exploration missions have cost ceilings and short development periods, heritage flight hardware is utilized. However, conceptual designs that rely solely on heritage technology will result in estimates that may not be truly representative of the actual mission being designed and built. The Laboratory for Spacecraft and Mission Design (LSMD) at the California Institute of Technology is developing integrated concurrent models for mass and cost estimations. The purpose of this project is to quantify the infusion of specific technologies where the data would be useful in guiding technology developments leading up to a mission. This paper introduces the design-to-cost model to determine the implications of various technologies on the spacecraft system in a collaborative engineering environment. In addition, comparisons of the benefits of new or advanced technologies for future deep space missions are examined
Brazilian version of the Functional Status Score for the ICU : translation and cross-cultural adaptation
Objetivo: traduzir e adaptar culturalmente a Escala de Estado Funcional em UTI (FSS-ICU - Functional Status Score for the ICU) para o portuguĂȘs do Brasil. MĂ©todos: o presente estudo consistiu das seguintes fases: tradução (realizada por dois tradutores independentes), sĂntese da tradução inicial, tradução de volta ao inglĂȘs (realizada por dois tradutores independentes nĂŁo familiarizados com a FSS-ICU original) e fase de teste, para avaliar a compreensĂŁo por parte da audiĂȘncia alvo. Um comitĂȘ de especialistas supervisionou todas as fases e foi responsĂĄvel pelos ajustes ao longo do processo e pela versĂŁo final da tradução. Resultados: a fase de testes incluiu dois fisioterapeutas experientes que avaliaram um total de 30 pacientes crĂticos (escore da FSS-ICU mĂ©dio de 25 ± 6). Como os fisioterapeutas nĂŁo relataram problemas com incertezas ou problemas de interpretação que afetassem seu desempenho, nĂŁo foram feitos outros ajustes Ă versĂŁo em portuguĂȘs brasileiro apĂłs a fase de teste. Obteve-se uma boa confiabilidade entre observadores para cada uma das cinco tarefas da FSS-ICU e entre os escores dos dois avaliadores (o coeficiente de correlação intraclasse variou de 0,88 a 0,91). ConclusĂŁo: a versĂŁo adaptada da FSS-ICU para o portuguĂȘs brasileiro comprovou ser de fĂĄcil compreensĂŁo e aplicação clĂnica no ambiente da unidade de terapia intensiva.Objective: the aim of the present study was to translate and cross-culturally adapt the Functional Status Score for the intensive care unit (FSS-ICU) into Brazilian Portuguese. Methods: this study consisted of the following steps: translation (performed by two independent translators), synthesis of the initial translation, back-translation (by two independent translators who were unaware of the original FSS-ICU), and testing to evaluate the target audience's understanding. An Expert Committee supervised all steps and was responsible for the modifications made throughout the process and the final translated version. Results: the testing phase included two experienced physiotherapists who assessed a total of 30 critical care patients (mean FSS-ICU score = 25 ± 6). As the physiotherapists did not report any uncertainties or problems with interpretation affecting their performance, no additional adjustments were made to the Brazilian Portuguese version after the testing phase. Good interobserver reliability between the two assessors was obtained for each of the 5 FSS-ICU tasks and for the total FSS-ICU score (intraclass correlation coefficients ranged from 0.88 to 0.91). Conclusion: the adapted version of the FSS-ICU in Brazilian Portuguese was easy to understand and apply in an intensive care unit environment
Do Human Milk Concentrations of Persistent Organic Chemicals Really Decline During Lactation? Chemical Concentrations During Lactation and Milk/Serum Partitioning
Expert consensus and recommendations on safety criteria for active mobilization of mechanically ventilated critically ill adults
Introduction:
The aim of this study was to develop consensus recommendations on safety parameters for mobilizing adult, mechanically ventilated, intensive care unit (ICU) patients.
Methods:
A systematic literature review was followed by a meeting of 23 multidisciplinary ICU experts to seek consensus regarding the safe mobilization of mechanically ventilated patients.
Results:
Safety considerations were summarized in four categories: respiratory, cardiovascular, neurological and other. Consensus was achieved on all criteria for safe mobilization, with the exception being levels of vasoactive agents. Intubation via an endotracheal tube was not a contraindication to early mobilization and a fraction of inspired oxygen less than 0.6 with a percutaneous oxygen saturation more than 90% and a respiratory rate less than 30 breaths/minute were considered safe criteria for in- and out-of-bed mobilization if there were no other contraindications. At an international meeting, 94 multidisciplinary ICU clinicians concurred with the proposed recommendations.
Conclusion:
Consensus recommendations regarding safety criteria for mobilization of adult, mechanically ventilated patients in the ICU have the potential to guide ICU rehabilitation whilst minimizing the risk of adverse events
Polycyclic Aromatic Hydrocarbons in Maternal and Umbilical Cord Blood from Pregnant Hispanic Women Living in Brownsville, Texas
Venous blood was drawn from 35 pregnant Hispanic women living in Brownsville, Texas, and matched cord blood was collected at birth. Gas chromatography/mass spectrometry was used to measure concentrations of 55 individual PAHs or groups of PAHs. Results indicate that these women and their fetuses were regularly exposed to multiple PAHs at comparatively low concentrations, with levels in cord blood generally exceeding levels in paired maternal blood. While the possibility of related adverse effects on the fetus is uncertain, these exposures in combination with socioeconomically-disadvantaged and environmentally-challenging living conditions raise legitimate public health concerns
Neuroimaging, clinical and life course correlates of normal-appearing white matter integrity in 70-year-olds
We investigate associations between normal-appearing white matter (NAWM) microstructural integrity in cognitively normal âŒ70-year-olds and concurrently measured brain health and cognition, demographics, genetics and life course cardiovascular health.
Participants born in the same week in March 1946 (British 1946 Birth cohort) underwent PET-MRI around age 70. Mean standardized NAWM integrity metrics (fractional anisotropy (FA), mean diffusivity (MD), neurite density index (NDI) and orientation dispersion index (ODI)) were derived from diffusion MRI. Linear regression was used to test associations between NAWM metrics and (1) concurrent measures, including whole brain volume, white matter hyperintensity volume (WMHV), PET amyloid and cognition; (2) the influence of demographic and genetic predictors, including sex, childhood cognition, education, socioeconomic position, and genetic risk for Alzheimerâs Disease (APOE-Δ4); (3) systolic and diastolic blood pressure and cardiovascular health (FHS-CVS) across adulthood. Sex interactions were tested. Statistical significance included false discovery rate correction (5%).
362 participants met inclusion criteria (mean age 70 years, 49% female). Higher WMHV was associated with lower FA (b=-0.09 [95%CI:-0.11, -0.06] p<0.01), NDI (b=-0.17 [-0.22, -0.12] p<0.01), and higher MD (b=0.14 [-0.10, -0.17] p<0.01); amyloid (in men) was associated with lower FA (b=-0.04 [-0.08, -0.01] p=0.03) and higher MD (b=0.06 [0.01,0.11] p=0.02). FHS-CVS in later-life (age 69) was associated with NAWM [lower FA (b=-0.06 [-0.09, -0.02] p<0.01), NDI (b=-0.10 [-0.17, -0.03] p<0.01), and higher MD (b=0.09 [0.04,0.14] p<0.01). Significant sex interactions (p<0.05) emerged for midlife cardiovascular health (age 53) and NAWM at 70: marginal effect plots demonstrated, in women only, NAWM was associated with higher midlife FHS-CVS (lower FA and NDI), midlife systolic (lower FA, NDI, and higher MD), and diastolic (lower FA and NDI) blood pressure, and greater blood pressure change between 43 and 53 years (lower FA and NDI), independently of WMHV.
In summary, poorer NAWM microstructural integrity in âŒ70-year-olds was associated with measures of cerebral small vessel disease, amyloid (in males) and later-life cardiovascular health, demonstrating how NAWM can provide additional information to overt white matter disease. Our findings further show that greater midlife cardiovascular risk and higher blood pressure were associated with poorer NAWM microstructural integrity in females only, suggesting that womenâs brains may be more susceptible to the effects of midlife blood pressure and cardiovascular health
Are adolescents with high socioeconomic status more likely to engage in alcohol and illicit drug use in early adulthood?
<p>Abstract</p> <p>Background</p> <p>Previous literature has shown a divergence by age in the relationship between socioeconomic status (SES) and substance use: adolescents with low SES are more likely to engage in substance use, as are adults with high SES. However, there is growing evidence that adolescents with high SES are also at high risk for substance abuse. The objective of this study is to examine this relationship longitudinally, that is, whether wealthier adolescents are more likely than those with lower SES to engage in substance use in early adulthood.</p> <p>Methods</p> <p>The study analyzed data from the National Longitudinal Survey of Adolescent Health (AddHealth), a longitudinal, nationally-representative survey of secondary school students in the United States. Logistic regression models were analyzed examining the relationship between adolescent SES (measured by parental education and income) and substance use in adulthood, controlling for substance use in adolescence and other covariates.</p> <p>Results</p> <p>Higher parental education is associated with higher rates of binge drinking, marijuana and cocaine use in early adulthood. Higher parental income is associated with higher rates of binge drinking and marijuana use. No statistically significant results are found for crystal methamphetamine or other drug use. Results are not sensitive to the inclusion of college attendance by young adulthood as a sensitivity analysis. However, when stratifying by race, results are consistent for white non-Hispanics, but no statistically significant results are found for non-whites. This may be a reflection of the smaller sample size of non-whites, but may also reflect that these trends are driven primarily by white non-Hispanics.</p> <p>Conclusions</p> <p>Previous research shows numerous problems associated with substance use in young adults, including problems in school, decreased employment, increases in convictions of driving under the influence (DUI) and accidental deaths. Much of the previous literature is focused on lower SES populations. Therefore, it is possible that teachers, parents and school administrators in wealthier schools may not perceive as great to address substance abuse treatment in their schools. This study can inform teachers, parents, school administrators and program officials of the need for addressing drug abuse prevention activities to this population of students.</p
Risk behaviors in a rural community with a known point-source exposure to chronic wasting disease
<p>Abstract</p> <p>Background</p> <p>The emergence and continuing spread of Chronic Wasting Disease (CWD) in cervids has now reached 14 U.S. states, two Canadian provinces, and South Korea, producing a potential for transmission of CWD prions to humans and other animals globally. In 2005, CWD spread for the first time from the Midwest to more densely populated regions of the East Coast. As a result, a large cohort of individuals attending a wild game feast in upstate New York were exposed to a deer that was subsequently confirmed positive for CWD.</p> <p>Methods</p> <p>Eighty-one participants who ingested or otherwise were exposed to a deer with chronic wasting disease at a local New York State sportsman's feast were recruited for this study. Participants were administered an exposure questionnaire and agreed to follow-up health evaluations longitudinally over the next six years.</p> <p>Results</p> <p>Our results indicate two types of risks for those who attended the feast, a <it>Feast Risk </it>and a G<it>eneral Risk</it>. The larger the number of risk factors, the greater the risk to human health if CWD is transmissible to humans. Long-term surveillance of feast participants exposed to CWD is ongoing.</p> <p>Conclusion</p> <p>The risk data from this study provide a relative scale for cumulative exposure to CWD-infected tissues and surfaces, and those in the upper tiers of cumulative risk may be most at risk if CWD is transmissible to humans.</p
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