11,632 research outputs found
Shock compression of liquid hydrazine
Liquid hydrazine (N{sub 2}H{sub 4}) is a propellant used by the Air Force and NASA for aerospace propulsion and power systems. Because the propellant modules that contain the hydrazine can be subject to debris impacts during their use, the shock states that can occur in the hydrazine need to be characterized to safely predict its response. Several shock compression experiments have been conducted in an attempt to investigate the detonability of liquid hydrazine; however, the experiments results disagree. Therefore, in this study, we reproduced each experiment numerically to evaluate in detail the shock wave profiles generated in the liquid hydrazine. This paper presents the results of each numerical simulation and compares the results to those obtained in experiment. We also present the methodology of our approach, which includes chemical kinetic experiments, chemical equilibrium calculations, and characterization of the equation of state of liquid hydrazine
Assessing the Influence of Living and Working Conditions on Alcohol Consumption in Migrant Farmworkers in Mexico
Background and Purpose: Inadequate working and living conditions are associated with alcohol consumption in farmworkers in the U.S. However, the influence of these factors on alcohol consumption patterns in migrant farmworkers in Mexico remains unclear. The purpose of this analysis was to assess the influence of housing and working conditions on alcohol use in migrant farmworkers in Mexico. Methods: We used logistic and ordinal logistic regression to examine the association of living and working conditions on alcohol consumption and frequency in 3,132 farmworkers in Mexico with data from a Mexican national farmworker’s survey. Results: Living in inadequately built homes (OR=0.84; 95% CI=0.72, 0.98; p<0.05) and limited access to luxury items (OR=0.69; 95% CI=0.52, 0.94; p<0.01), were associated with a decreased likelihood to consume alcohol compared to living in better conditions. In contrast, living in employer provided housing (OR=1.79; 95% CI=1.40, 2.31; p<0.0001) and experiencing hazards related to safety (OR= 1.69; 95% CI= 1.35, 2.12; p<0.0001), work organization (OR= 1.29; CI= 1.03, 1.63; p<0.05), and ergonomics (OR= 2.04; CI= 1.18, 3.52; p<0.05) increased the likelihood of consuming alcohol. Conclusion: Living and working conditions of farmworkers may affect alcohol consumption. However, these findings require replication and specific mechanisms, which may influence these results warrants investigation
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Understanding Social and Cultural Contexts of Alcohol Misuse in Mexican-Origin Hispanic Men
Evidence suggests that Hispanic and non-Hispanic White men (NHW) have comparable prevalence rates of alcohol use. However, Hispanic men consistently have higher prevalence rates of alcohol misuse compared with NHW men. Consequently, Hispanic men experience disproportionate levels of adverse health consequences of alcohol misuse when compared with NHW men. The aim of this study was to explore Hispanic male perspectives and opinions regarding alcohol use patterns that may lead to disparate rates of alcohol misuse in Hispanic males. Demographic data were collected with questionnaires. Twenty semistructured one-on-one interviews were completed in English and Spanish with Mexican-origin Hispanic men (age: 44.6 +/- 11.3 years). A thematic analysis was conducted using a hybrid deductive-inductive strategy with an a priori codebook supplemented with iterative analysis of transcripts. Results suggest that alcohol misuse patterns in Hispanic males are influenced by an interaction between alcohol-related social norms and learned expressions of masculinity; a lack of knowledge of the alcohol-related health risks that further perpetuate the normalization of alcohol misuse; and expressions of masculinity and adaptive coping that lead to alcohol misuse as an escape from life stressors. Given the rapid expansion of the Hispanic population in the United States, and the disparate consequences of alcohol misuse in this population, it is imperative to consider the complex and often compounded impact of sociocultural norms and the social context on misuse-related behaviors. Viable prevention and treatment strategies should be addressed thought multicomponent, community-level strategies that more comprehensively address the complexities of alcohol misuse in this population.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Circulation first – the time has come to question the sequencing of care in the ABCs of trauma; an American Association for the Surgery of Trauma multicenter trial
Background The traditional sequence of trauma care: Airway, Breathing, Circulation (ABC) has been practiced for many years. It became the standard of care despite the lack of scientific evidence. We hypothesized that patients in hypovolemic shock would have comparable outcomes with initiation of bleeding treatment (transfusion) prior to intubation (CAB), compared to those patients treated with the traditional ABC sequence. Methods This study was sponsored by the American Association for the Surgery of Trauma multicenter trials committee. We performed a retrospective analysis of all patients that presented to trauma centers with presumptive hypovolemic shock indicated by pre-hospital or emergency department hypotension and need for intubation from January 1, 2014 to July 1, 2016. Data collected included demographics, timing of intubation, vital signs before and after intubation, timing of the blood transfusion initiation related to intubation, and outcomes. Results From 440 patients that met inclusion criteria, 245 (55.7%) received intravenous blood product resuscitation first (CAB), and 195 (44.3%) were intubated before any resuscitation was started (ABC). There was no difference in ISS, mechanism, or comorbidities. Those intubated prior to receiving transfusion had a lower GCS than those with transfusion initiation prior to intubation (ABC: 4, CAB:9, p = 0.005). Although mortality was high in both groups, there was no statistically significant difference (CAB 47% and ABC 50%). In multivariate analysis, initial SBP and initial GCS were the only independent predictors of death. Conclusion The current study highlights that many trauma centers are already initiating circulation first prior to intubation when treating hypovolemic shock (CAB), even in patients with a low GCS. This practice was not associated with an increased mortality. Further prospective investigation is warranted. Trial registration IRB approval number: HM20006627. Retrospective trial not registered
EvaluaciĂłn nutricional pre-operatoria en pacientes de cirugĂa del ClĂnico QuirĂşrgico “10 de Octubre”.
La evaluaciĂłn del estado nutricional en el paciente quirĂşrgico es un aspecto no solo necesario sino imprescindible. Objetivo: Determinar el estado nutricional preoperatorio de los pacientes intervenidos quirĂşrgicamente en la modalidad de cirugĂa electiva. MetodologĂa: Se realizĂł un estudio observacional, descriptivo, longitudinal y prospectivo en el servicio de cirugĂa del Hospital ClĂnico QuirĂşrgico “10 de Octubre” de la Habana desde el mes de mayo 2013 hasta septiembre 2013 con pacientes que acudieron a consulta para ser intervenidos quirĂşrgicamente en la modalidad de cirugĂa electiva. Seutilizaron indicadores antropomĂ©tricos (ĂŤndice de masa corporal, circunferencia del brazo y de la pierna) y bioquĂmicos (hemoglobina, albĂşmina, colesterol, conteo total de linfocitos, creatinina y triglicĂ©ridos).Resultados: Predominaron en el estudio pacientes del sexo femenino y mayores de 50 años. Las afecciones de las vĂas biliares y las neoplásicas fueron las más representadas. SegĂşn las pruebas antropomĂ©tricas la mitad de los pacientes clasifican como sobrepeso por ĂŤndice de masa corporal y por la circunferencia del brazo y la pierna, y desnutridos la otra mitad de la muestra. Las variables bioquĂmicas demostraron que más de la mitad de los pacientes tenĂan anemia, mientras que el conteo total de linfocitos estaba disminuido en la tercera parte de la muestra y las cifras de creatinina eran normales en la mayorĂa de los pacientes al igual que la albĂşmina. Las cifras de colesterol y triglicĂ©ridos estaban elevadas en la cuarta parte de los pacientes, lo que pudiera estar en correspondencia con el alto porcentaje de afectados con sobrepeso y obesidad
Pilot Feasibility Study of a Campaign Intervention for Weight Loss among Overweight and Obese Adults
Background: Behavioral interventions produce significant short-term weight loss. However, these interventions typically require regular in-person sessions, which may not be feasible for all individuals. Purpose: The purpose of this pilot study was to evaluate the feasibility of a 12-week campaign intervention (CI) compared to a standard on-site, group-based behavioral weight loss intervention (SBWL) among overweight/obese adults. Methods: SBWL participants (n=13; age: 42.5 ± 9.1 years; BMI: 33.4 ± 3.8 kg/m²) attended weekly group meetings, were prescribed a daily reduced caloric goal and 200 minutes of moderate-intensity physical activity per week. CI participants (n=13; age: 43.8 ± 9.0 years; BMI: 33.2 ± 3.8 kg/m²) received the same recommendations as the SBWL, attended in-person group meetings at weeks 0 and 12, and received e-mail messages weeks 2-11. Additional CI features included a thematic framework and an incentive-based point system targeting behavioral goals. Results: Significant weight loss was demonstrated for intention-to-treat (SBWL: -5.6 ± 2.9 kg; CI: -3.1 ± 3.4 kg) (
Leveraging omic features with F3UTER enables identification of unannotated 3'UTRs for synaptic genes
There is growing evidence for the importance of 3' untranslated region (3'UTR) dependent regulatory processes. However, our current human 3'UTR catalogue is incomplete. Here, we develop a machine learning-based framework, leveraging both genomic and tissue-specific transcriptomic features to predict previously unannotated 3'UTRs. We identify unannotated 3'UTRs associated with 1,563 genes across 39 human tissues, with the greatest abundance found in the brain. These unannotated 3'UTRs are significantly enriched for RNA binding protein (RBP) motifs and exhibit high human lineage-specificity. We find that brain-specific unannotated 3'UTRs are enriched for the binding motifs of important neuronal RBPs such as TARDBP and RBFOX1, and their associated genes are involved in synaptic function. Our data is shared through an online resource F3UTER ( https://astx.shinyapps.io/F3UTER/ ). Overall, our data improves 3'UTR annotation and provides additional insights into the mRNA-RBP interactome in the human brain, with implications for our understanding of neurological and neurodevelopmental diseases
Critical behavior of 2 and 3 dimensional ferro- and antiferromagnetic spin ice systems in the framework of the Effective Field Renormalization Group technique
In this work we generalize and subsequently apply the Effective Field
Renormalization Group technique to the problem of ferro- and
antiferromagnetically coupled Ising spins with local anisotropy axes in
geometrically frustrated geometries (kagome and pyrochlore lattices). In this
framework, we calculate the various ground states of these systems and the
corresponding critical points. Excellent agreement is found with exact and
Monte Carlo results. The effects of frustration are discussed. As pointed out
by other authors, it turns out that the spin ice model can be exactly mapped to
the standard Ising model but with effective interactions of the opposite sign
to those in the original Hamiltonian. Therefore, the ferromagnetic spin ice is
frustrated, and does not order. Antiferromagnetic spin ice (in both 2 and 3
dimensions), is found to undergo a transition to a long range ordered state.
The thermal and magnetic critical exponents for this transition are calculated.
It is found that the thermal exponent is that of the Ising universality class,
whereas the magnetic critical exponent is different, as expected from the fact
that the Zeeman term has a different symmetry in these systems. In addition,
the recently introduced Generalized Constant Coupling method is also applied to
the calculation of the critical points and ground state configurations. Again,
a very good agreement is found with both exact, Monte Carlo, and
renormalization group calculations for the critical points. Incidentally, we
show that the generalized constant coupling approach can be regarded as the
lowest order limit of the EFRG technique, in which correlations outside a
frustrated unit are neglected, and scaling is substituted by strict equality of
the thermodynamic quantities.Comment: 28 pages, 9 figures, RevTeX 4 Some minor changes in the conclussions.
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