2,693 research outputs found

    A practical approach to estimate resting energy expenditure in frail elderly people

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    Objectives: Some prediction equations of resting energy expenditure (REE) are available and can be used in clinical wards to determine energy requirements of patients. The aim of the present study was to assess the accuracy of those equations in sick elderly patients, using the Bland & Altman methods with our database of 187 REE measurements.Design: The 3 equations tested were Harris & Benedict equation of 1919, WHO/FAO/UNU equation of 1985 and Fredrix et al. equation of 1990. In addition, three models developed from the present data were tested.Results: The present study shows that the Fredrix et al equation gave an accurate prediction of REE without significant bias along the whole range of REE. It also shows that under-weight sick elderly patients (BMI ≤ 21 kg/m2) had a greater weight-adjusted REE than their normal weight counterparts.Conclusion: A simple formula using a factor multiplying body weight, i.e. 22 kcal/kg/d in under-weight and 19 kcal/kg/d in normal weight sick elderly was accurate to predicting REE and bias was not influenced by the level of REE. This model included half of the group in the range of ±10% of the difference between predicted REE and measured REE, but the confidence interval of the bias was ±400 kcal/d. Conversely, the Harris & Benedict and WHO formulae did accurately predict REE

    Effects of Intravenous Aspirin on Prostaglandin Synthesis and Kidney Function in Intensive Care Patients

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    The effects of intravenous acetylsalicylic acid (1.0 g bolus) on renal function and prostaglandin synthesis were evaluated in a prospective, controlled study in eight patients in an intensive care unit. Four of these patients had congestive heart failure. Administration of acetylsalicylic acid caused significant antidiuresis (−56%), antinatriuresis (−82%), renin suppression (−26%) and decreased GFR (−41%). All of these changes were completely reversible within 1-2 hours and tended to be more pronounced in the patients with congestive heart failure. Urinary excretion of prostaglandin E was depressed profoundly (−93%) and did not return to more than 45% of control 6 h after the administration of acetylsalicylic acid. We conclude that intravenous acetylsalicylic acid affects kidney function in a manner similar to other prostaglandin synthesis inhibitors. Its effects are, however, short-lived. The inhibition of urinary PGE2 excretion outlasts GFR depression, antidiuresis, antinatriuresis and renin suppression by several hour

    Period Integrals, Quantum Numbers and Confinement in SUSY QCD

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    We present a direct computation of the period integrals on degenerate Seiberg-Witten curves for supersymmetric QCD, and show how these periods determine the changes in the quantum numbers of the states, when passing from the weak to the strong-coupling domains in the mass moduli space of the theory. The confinement of monopoles at strong coupling is discussed, and we demonstrate that the ambiguities in choosing the way in the moduli space do not influence to the physical conclusions on confinement of monopoles in the phase with the condensed light dyons.Comment: 16 pages, contribution to special volume on Integrable Systems in Quantum Theor

    Adaptation to the Edge of Chaos in the Self-Adjusting Logistic Map

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    Self-adjusting, or adaptive systems have gathered much recent interest. We present a model for self-adjusting systems which treats the control parameters of the system as slowly varying, rather than constant. The dynamics of these parameters is governed by a low-pass filtered feedback from the dynamical variables of the system. We apply this model to the logistic map and examine the behavior of the control parameter. We find that the parameter leaves the chaotic regime. We observe a high probability of finding the parameter at the boundary between periodicity and chaos. We therefore find that this system exhibits adaptation to the edge of chaos.Comment: 3 figure

    Characteristics of Control Laws Tested on the Semi-Span Super-Sonic Transport (S4T) Wind-Tunnel Model

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    The Semi-Span Supersonic Transport (S4T) is an aeroelastically scaled wind-tunnel model built to test active controls concepts for large flexible supersonic aircraft in the transonic flight regime. It is one of several models constructed in the 1990's as part of the High Speed Research (HSR) Program. Control laws were developed for the S4T by M4 Engineering, Inc. and by Zona Technologies, Inc. under NASA Research Announcement (NRA) contracts. The model was tested in the NASA-Langley Transonic Dynamics Tunnel (TDT) four times from 2007 to 2010. The first two tests were primarily for plant identification. The third entry was used for testing control laws for Ride Quality Enhancement, Gust Load Alleviation, and Flutter Suppression. Whereas the third entry only tested FS subcritically, the fourth test demonstrated closed-loop operation above the open-loop flutter boundary. The results of the third entry are reported elsewhere. This paper reports on flutter suppression results from the fourth wind-tunnel test. Flutter suppression is seen as a way to provide stability margins while flying at transonic flight conditions without penalizing the primary supersonic cruise design condition. An account is given for how Controller Performance Evaluation (CPE) singular value plots were interpreted with regard to progressing open- or closed-loop to higher dynamic pressures during testing

    Neonates with SARS-CoV-2 infection: spectrum of disease from a prospective nationwide observational cohort study.

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    Coronavirus disease 2019 (COVID-19) can be more severe in infants than in older children. To date, only a few case series have reported data on neonates with COVID-19, including mostly asymptomatic neonates who were tested because of exposure to maternal SARS-CoV-2 infection. This study summarises nationwide epidemiological data, clinical characteristics, treatment and outcomes of neonates presenting with symptomatic SARS-CoV-2 infection. Data were prospectively collected through the Swiss Paediatric Surveillance Unit from hospitalised neonates with laboratory-confirmed SARS-CoV-2 infection (positive polymerase chain reaction on a respiratory sample) from 1 March 2020 to 31 September 2021. All 29 paediatric hospitals in Switzerland reported cases. In total, 73 neonates were included; 7 (10%) were preterm. The median age at presentation was 17 days (interquartile range [IQR] 11-23); 40 (55%) were female. The majority of neonates (64, 88%) were admitted from home. Nine (12%) had a pre-existing medical condition. Overall, the most common symptom recorded was fever in 52 (71%), followed by rhinorrhoea or nasal congestion in 32 (44%) and respiratory distress in 19 (26%). Twenty (27%) neonates presented with fever without a source. Seven (10%) neonates were admitted to an intensive care unit (5 for respiratory failure and 2 for monitoring). One (1%) neonate required inotropic support. The median length of hospital stay in term neonates was 4 days (IQR 3-5). Two (3%) were treated with corticosteroids and 1 (1%) with remdesivir. In total, 60 (82%) neonates had contact with a known or suspected SARS-CoV-2 index case. All of the 71 neonates for whom data were available were discharged to their homes without symptoms. In neonates, COVID-19 mainly presents with fever, and symptoms of upper and lower respiratory tract infection. The clinical course is mostly mild, requiring a short period of hospitalisation. COVID-19 needs to be added as a differential diagnosis in neonates who present with fever without a source. However, the presence of SARS-CoV-2 should not deter from the search for a serious bacterial infection. Further data from surveillance studies are needed to better understand COVID-19 in neonates, guide therapy and to evaluate whether the clinical spectrum is changing with new SARS-CoV-2 variants

    Distribution of adipose tissue: Quantification and relationship with hepatic steatosis and vascular profiles of type 2 diabetic patients with metabolic syndrome

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    AimAs the distribution of fat is increasingly related to cardiovascular events, we examined whether or not abdominal-fat quantification using magnetic resonance imaging (MRI) software is reliable, and whether or not it is related to clinical markers of fat distribution as well as to metabolic and vascular status. Methods We recorded the anthropometric measurements of 34 obese type 2 diabetic patients with metabolic syndrome. The patients were enrolled to evaluate their abdominal (visceral and subcutaneous) adipose tissue by single-slice L3–L4 MRI. Manual and automated analyses were compared. The relationships between anthropometric measurements, biological markers and intima-media thickness of the common carotid artery were also assessed. Results We validated the automated software to quantify abdominal-fat deposition with MRI compared with manual measurements (r2 = 0.95). The waist-to-hip-circumference ratio (WHR) was the only clinical parameter that correlated with the proportion and quantity of visceral and subcutaneous abdominal-adipose tissue evaluated by MRI (r = 0.60). In addition, fat repartition as evaluated by WHR was related to hepatic steatosis parameters (ferritin and ALAT) and to intima-media thickness, whereas simple waist circumference was not a determinant in these obese patients. We also showed that the adiponectin-to-leptin ratio was related to adipose tissue distribution. Conclusion Distribution of abdominal fat, as evaluated by MRI, can be reflected by clinical determination of the WHR. Differences in regional accumulations of abdominal fat may be specifically related to variations in the risks of steatosis and vascular rigidity among obese type 2 diabetic patients

    Complete synchronization in coupled Type-I neurons

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    For a system of type-I neurons bidirectionally coupled through a nonlinear feedback mechanism, we discuss the issue of noise-induced complete synchronization (CS). For the inputs to the neurons, we point out that the rate of change of instantaneous frequency with the instantaneous phase of the stochastic inputs to each neuron matches exactly with that for the other in the event of CS of their outputs. Our observation can be exploited in practical situations to produce completely synchronized outputs in artificial devices. For excitatory-excitatory synaptic coupling, a functional dependence for the synchronization error on coupling and noise strengths is obtained. Finally we report an observation of noise-induced CS between non-identical neurons coupled bidirectionally through random non-zero couplings in an all-to- all way in a large neuronal ensemble.Comment: 24 pages, 9 figure
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