400 research outputs found
Phase-locked telemetry system for rotary instrumentation of turbomachinery, phase 1
A telemetry system for use in making strain and temperature measurements on the rotating components of high speed turbomachines employs phase locked transmitters, which offer greater measurement channel capacity and reliability than existing systems which employ L-C carrier oscillators. A prototype transmitter module was tested at 175 C combined with 40,000 g's acceleration
Between-centre differences in care for in-hospital cardiac arrest:a prospective cohort study
Abstract Background Survival after in-hospital cardiac arrest is poor, but current literature shows substantial heterogeneity in reported survival rates. This study aims to evaluate care for patients suffering in-hospital cardiac arrest (IHCA) in the Netherlands by assessing between-hospital heterogeneity in outcomes and to explain this heterogeneity stemming from differences in case-mix or differences in quality of care. Methods A prospective multicentre study was conducted comprising 14 centres. All IHCA patients were included. The adjusted variation in structure and process indicators of quality of care and outcomes (in-hospital mortality and cerebral performance category [CPC] scale) was assessed with mixed effects regression with centre as random intercept. Variation was quantified using the median odds ratio (MOR), representing the expected odds ratio for poor outcome between two randomly picked centres. Results After excluding centres with less than 10 inclusions (2 centres), 701 patients were included of whom, 218 (32%) survived to hospital discharge. The unadjusted and case-mix adjusted MOR for mortality was 1.19 and 1.05, respectively. The unadjusted and adjusted MOR for CPC score was 1.24 and 1.19, respectively. In hospitals where personnel received cardiopulmonary resuscitation (CPR) training twice per year, 183 (64.7%) versus 290 (71.4%) patients died or were in a vegetative state, and 59 (20.8%) versus 68 (16.7%) patients showed full recovery (p < 0.001). Conclusion In the Netherlands, survival after IHCA is relatively high and between-centre differences in outcomes are small. The existing differences in survival are mainly attributable to differences in case-mix. Variation in neurological outcome is less attributable to case-mix
Mechanistic insights into the role of large carnivores for ecosystem structure and functioning
Large carnivores can exert top–down effects in ecosystems, but the size of these effects are largely unknown. Empirical investigation on the importance of large carnivores for ecosystem structure and functioning presents a number of challenges due to the large spatio-temporal scale and the complexity of such dynamics. Here, we applied a mechanistic global ecosystem model to investigate the influence of large-carnivore removal from undisturbed ecosystems. First, we simulated large-carnivore removal on the global scale to inspect the geographic pattern of top–down control and to disentangle the functional role of large carnivores in top–down control in different environmental contexts. Second, we conducted four small-scale ecosystem simulation experiments to understand direct and indirect changes in food-web structure under different environmental conditions. We found that the removal of top–down control exerted by large carnivores (> 21 kg) can trigger large trophic cascades, leading to an overall decrease in autotroph biomass globally. Furthermore, the loss of large carnivores resulted in an increase of mesopredators. The magnitude of these changes was positively related to primary productivity (NPP), in line with the ‘exploitation ecosystem hypothesis’. In addition, we found that seasonality in NPP dampened the magnitude of change following the removal of large carnivores. Our results reinforce the idea that large carnivores play a fundamental role in shaping ecosystems, and further declines and extinctions can trigger substantial ecosystem responses. Our findings also support previous studies suggesting that natural ecosystem dynamics have been severely modified and are still changing as a result of the widespread decline and extinction of large carnivores
Sweet Temptations:How Does Reading a Fotonovela About Diabetes Affect Dutch Adults with Different Levels of Literacy?
Recent studies suggest that health-related fotonovelas-booklets that portray a dramatic story using photographs and captions-may be effective health communication tools, especially for readers with a low level of literacy. In this experiment, effects on knowledge and behavioral intentions were assessed of a fotonovela originally developed for a Latin-American audience. Dutch readers from a low literacy group (N = 89) and a high literacy group (N = 113) were randomly assigned to one of three conditions: a fotonovela condition (all captions translated into Dutch), a traditional brochure condition (also in Dutch), and a control condition. On knowledge about diabetes, participants in the fotonovela condition outperformed participants in both other conditions. This finding was consistent across literacy levels. On behavioral intentions, however, readers of the fotonovela did not score significantly higher than participants in the other conditions. We also evaluated hypotheses proposed in the Entertainment Overcoming Resistance Model (EORM; Moyer-Guse, 2008) on the possible mechanisms underlying persuasion through narratives. No support was found for the mechanisms proposed in the EORM. The outcomes of this study suggest that a fotonovela may be a valuable health education format for adults with varying levels of literacy, even if it was developed for a target group with a different cultural background.</p
Shifts in ecosystem equilibria following trophic rewilding
Aim: Trophic rewilding is proposed as an approach to tackle biodiversity loss by restoring ecosystem dynamics through the reintroduction of keystone species. Currently, evidence on the ecological consequences of reintroduction programmes is sparse and difficult to generalize. To better understand the ecological consequences of trophic rewilding, we simulated the extinction and reintroduction of large-bodied mammals under different environmental conditions.
Location: Europe.
Methods: We selected four locations varying in productivity and seasonality in Europe and used a general ecosystem model called Madingley to run simulations. We initialized the model using body mass limits of a European Holocene baseline; we then removed large mammals and let the model converge to a new equilibrium. Next, we reintroduced the previously removed groups to assess whether the equilibrium would shift back to the initial condition. We tested three different reintroduction scenarios, in order to disentangle the importance of the different large mammal groups.
Results: The removal of large-bodied mammals led to cascading effects, mainly resulting in increases in smaller-bodied herbivores and the release of mesopredators. Post-reintroduction, the system's new equilibrium state was closer to the initial equilibrium for stable and productive locations compared to highly seasonal and low-productive locations. The maximum trait space volume of the initial state and the post-reintro-duction state varied by 9.1% on average over all locations, with an average decrease in trait combinations of 6.6%. The body mass distribution differed by 28%, comparing the initial state to the post-reintroduction state.
Main Conclusions: Our simulation results suggest that reintroducing locally extinct large-bodied mammals can broadly restore shifts in ecosystem structure, roughly resembling the baseline ecosystem conditions. However, the extent to which the ecosystem's state resembles the original ecosystem is largely dependent on the reintroduction strategy (only herbivores and omnivores vs. also carnivores) and timing, as well as local environmental conditions
Immediate postoperative high-sensitivity troponin T concentrations and long-term patient-reported
BACKGROUND: Myocardial injury after noncardiac surgery is associated with mortality and major adverse postoperative cardiovascular events. The effect of postoperative troponin concentrations on patient-reported health-related quality of life (HRQoL) is unknown. OBJECTIVE: The study examined the association between immediate postoperative troponin concentrations and self-reported HRQoL 1 year after surgery. DESIGN: Prospective cohort study. SETTING: Single-centre tertiary care hospital in the Netherlands between July 2012 and 2015. PATIENTS: Patients aged at least 60 years undergoing moderate and major noncardiac surgery.None. MAIN OUTCOME MEASURES: HRQoL total score was assessed with the EuroQol five-dimensional questionnaire. Tobit regression analysis was used to determine the association between postoperative troponin concentrations and 1-year HRQoL. Peak high-sensitivity troponin T values were divided into four categories: less than 14, 14 to 49, 50 to 149 and at least 150 ng l. RESULTS: A total of 3085 patients with troponin measurements were included. 2634 (85.4%) patients were alive at 1-year follow-up of whom 1297 (49.2%) returned a completed questionnaire. The median score for HRQoL was 0.82 (0.85, 0.81, 0.77 and 0.71 per increasing troponin category). Multivariable analysis revealed betas of -0.06 [95% confidence interval (CI) -0.09 to -0.02], -0.11 (95% CI -0.18 to -0.04) and -0.18 (95% CI -0.29 to -0.07) for troponin levels of 14 to 49, 50 to 149 and at least 150 ng l when compared with values less than 14 ng l. Other independent predictors for lower HRQoL were chronic obstructive pulmonary disease, female sex, peripheral arterial disease and increasing age. CONCLUSION: Higher levels of postoperative troponin measured immediately after surgery were independently associated with lower self-reported HRQoL total score at 1-year follow-up
SIRT3 overexpression in rat muscle does not ameliorate peripheral insulin resistance
Reduced expression of the NAD+-dependent deacetylase, SIRT3, has been associated with insulin resistance and metabolic dysfunction in humans and rodents. In this study, we investigated whether specific overexpression of SIRT3 in vivo in skeletal muscle could prevent high-fat diet (HFD)-induced muscle insulin resistance. To address this, we used a muscle-specific adeno-associated virus (AAV) to overexpress SIRT3 in rat tibialis and extensor digitorum longus (EDL) muscles. Mitochondrial substrate oxidation, substrate switching and oxidative enzyme activity were assessed in skeletal muscles with and without SIRT3 overexpression. Muscle-specific insulin action was also assessed by hyperinsulinaemic-euglycaemic clamps in rats that underwent a 4-week HFD-feeding protocol. Ex vivo functional assays revealed elevated activity of selected SIRT3-target enzymes including hexokinase, isocitrate dehydrogenase and pyruvate dehydrogenase that was associated with an increase in the ability to switch between fatty acid- and glucose-derived substrates in muscles with SIRT3 overexpression. However, during the clamp, muscles from rats fed an HFD with increased SIRT3 expression displayed equally impaired glucose uptake and insulin-stimulated glycogen synthesis as the contralateral control muscle. Intramuscular triglyceride content was similarly increased in the muscle of high-fat-fed rats, regardless of SIRT3 status. Thus, despite SIRT3 knockout (KO) mouse models indicating many beneficial metabolic roles for SIRT3, our findings show that muscle-specific overexpression of SIRT3 has only minor effects on the acute development of skeletal muscle insulin resistance in high-fat-fed rats
Factors Influencing Terrestriality in Primates of the Americas and Madagascar
Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (bodymass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use
Conservative Treatment in Diverticulitis Patients with Pericolic Extraluminal Air and the Role of Antibiotic Treatment
Background: Recently published studies advocate a conservative approach with observation and antibiotic treatment in diverticulitis patients with pericolic air on computed tomography (CT). The primary aim of this study was to assess the clinical course of initially conservatively treated diverticulitis patients with isolated pericolic air and to identify risk factors for conservative treatment failure. The secondary aim was to assess the outcome of non-antibiotic treatment. Methods: Patient data from a retrospective cohort study on risk factors for complicated diverticulitis were combined with data from the DIABOLO trial, a randomised controlled trial comparing non-antibiotic with antibiotic treatment in patients with uncomplicated diverticulitis. The present study identified all patients with Hinchey 1A diverticulitis with isolated pericolic air on CT. Pericolic air was defined as air located < 5 cm from the affected segment of colon. The primary outcome was failure of conservative management which was defined as need for percutaneous abscess drainage or emergency surgery within 30 days after presentation. A multivariable logistic regression of clinical, radiological and laboratorial parameters with respect to treatment failure was performed. Results: A total of 109 patients were included in the study. Fifty-two (48%) patients were treated with antibiotics. Nine (8%) patients failed conservative management, seven (13%) in the antibiotic treatment group and two (4%) in the non-antibiotic group (p = 0.083). Only (increased) CRP level at presentation was an independent predictor for treatment failure. Conclusions: Conservative treatment in diverticulitis patients with isolated pericolic air is a suitable treatment strategy. Moreover, non-antibiotic treatment might be reasonable in selected patients
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