1,968 research outputs found
Prescribed hypocaloric nutrition support for critically-ill adults
Background There are controversies about the amount of calories and the type of nutritional support that should be given to criticallyâill people. Several authors advocate the potential benefits of hypocaloric nutrition support, but the evidence is inconclusive. Objectives To assess the effects of prescribed hypocaloric nutrition support in comparison with standard nutrition support for criticallyâill adults Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Cochrane Library), MEDLINE, Embase and LILACS (from inception to 20 June 2017) with a specific strategy for each database. We also assessed three websites, conference proceedings and reference lists, and contacted leaders in the field and the pharmaceutical industry for undetected/unpublished studies. There was no restriction by date, language or publication status. Selection criteria We included randomized and quasiârandomized controlled trials comparing hypocaloric nutrition support to normoâ or hypercaloric nutrition support or no nutrition support (e.g. fasting) in adults hospitalized in intensive care units (ICUs). Data collection and analysis We used standard methodological procedures expected by Cochrane. We metaâanalysed data for comparisons in which clinical heterogeneity was low. We conducted prespecified subgroup and sensitivity analyses, and post hoc analyses, including metaâregression. Our primary outcomes were: mortality (death occurred during the ICU and hospital stay, or 28â to 30âday allâcause mortality); length of stay (days stayed in the ICU and in the hospital); and Infectious complications. Secondary outcomes included: length of mechanical ventilation. We assessed the quality of evidence with GRADE. Main results We identified 15 trials, with a total of 3129 ICU participants from universityâassociated hospitals in the USA, Colombia, Saudi Arabia, Canada, Greece, Germany and Iran. There are two ongoing studies. Participants suffered from medical and surgical conditions, with a variety of inclusion criteria. Four studies used parenteral nutrition and nine studies used only enteral nutrition; it was unclear whether the remaining two used parenteral nutrition. Most of them could not achieve the proposed caloric targets, resulting in small differences in the administered calories between intervention and control groups. Most studies were funded by the US government or nonâgovernmental associations, but three studies received funding from industry. Five studies did not specify their funding sources. The included studies suffered from important clinical and statistical heterogeneity. This heterogeneity did not allow us to report pooled estimates of the primary and secondary outcomes, so we have described them narratively. When comparing hypocaloric nutrition support with a control nutrition support, for hospital mortality (9 studies, 1775 participants), the risk ratios ranged from 0.23 to 5.54; for ICU mortality (4 studies, 1291 participants) the risk ratios ranged from 0.81 to 5.54, and for mortality at 30 days (7 studies, 2611 participants) the risk ratios ranged from 0.79 to 3.00. Most of these estimates included the null value. The quality of the evidence was very low due to unclear or high risk of bias, inconsistency and imprecision. Participants who received hypocaloric nutrition support compared to control nutrition support had a range of mean hospital lengths of stay of 15.70 days lower to 10.70 days higher (10 studies, 1677 participants), a range of mean ICU lengths of stay 11.00 days lower to 5.40 days higher (11 studies, 2942 participants) and a range of mean lengths of mechanical ventilation of 13.20 days lower to 8.36 days higher (12 studies, 3000 participants). The quality of the evidence for this outcome was very low due to unclear or high risk of bias in most studies, inconsistency and imprecision. The risk ratios for infectious complications (10 studies, 2804 participants) of each individual study ranged from 0.54 to 2.54. The quality of the evidence for this outcome was very low due to unclear or high risk of bias, inconsistency and imprecision We were not able to explain the causes of the observed heterogeneity using subgroup and sensitivity analyses or metaâregression. Authors' conclusions The included studies had substantial clinical heterogeneity. We found very lowâquality evidence about the effects of prescribed hypocaloric nutrition support on mortality in hospital, in the ICU and at 30 days, as well as in length of hospital and ICU stay, infectious complications and the length of mechanical ventilation. For these outcomes there is uncertainty about the effects of prescribed hypocaloric nutrition, since the range of estimates includes both appreciable benefits and harms. Given these limitations, results must be interpreted with caution in the clinical field, considering the unclear balance of the risks and harms of this intervention. Future research addressing the clinical heterogeneity of participants and interventions, study limitations and sample size could clarify the effects of this intervention.Fil: Perman, Mario I. Hospital Italiano; ArgentinaFil: Ciapponi, AgustĂn. Instituto de Efectividad ClĂnica y Sanitaria; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Franco, Juan V.A.. Hospital Italiano; ArgentinaFil: Loudet, Cecilia. Universidad Nacional de La Plata; ArgentinaFil: Crivelli, Adriana. Hospital HIGA San MartĂn; ArgentinaFil: Garrote, Virginia. Hospital Italiano; ArgentinaFil: Perman, GastĂłn. Hospital Italiano; Argentin
Unit Roots and Structural Breaks: A Survey of the Literature
Since Perron (1989) the time series literature has emphasised the importance of testing for structural breaks in typical economic data sets and pronounced the implications of structural breaks when testing for unit root processes. In this paper we survey recent developments in testing for unit roots taking account of possible structural breaks. In doing so we discuss the distinction between taking structural break dates as exogenously determined, an approach initially adopted in the literature, and endogenously testing break dates. That is, we differentiate between testing for breaks when the break date is known and when it is assumed to be unknown. Also important is the distinction between discrete breaks and gradual breaks. Additionally we describe tests for both single and multiple breaks and discuss some of the pitfalls of the latter.
Evidence from panel unit root and cointegration tests that the Environmental Kuznets Curve does not exist
The Environmental Kuznets Curve (EKC) hypothesis â an inverted U-shape relation between various indicators of environmental degradation and income per capita â has become one of the âstylised factsâ of environmental and resource economics. This is despite considerable criticism on both theoretical and empirical grounds. Cointegration analysis can be used to test the validity of such stylised facts when the data involved contain stochastic trends. In the present paper, we use cointegration analysis to test the EKC hypothesis using a panel dataset of sulfur emissions and GDP data for 74 countries over a span of 31 years. We find that the data is stochastically trending in the time-series dimension. Given this, and interpreting the EKC as a long run equilibrium relationship, support for the hypothesis requires that an appropriate model cointegrates and that sulfur emissions are a concave function of income. Individual and panel cointegration tests cast doubt on the general applicability of the hypothesised relationship. Even when we find cointegration, many of the relationships for individual countries are not concave. The results show that the EKC is a problematic concept, at least in the case of sulfur emissions.Environmental Economics and Policy,
Ruin probabilities and decompositions for general perturbed risk processes
We study a general perturbed risk process with cumulative claims modelled by
a subordinator with finite expectation, with the perturbation being a
spectrally negative Levy process with zero expectation. We derive a
Pollaczek-Hinchin type formula for the survival probability of that risk
process, and give an interpretation of the formula based on the decomposition
of the dual risk process at modified ladder epochs
Andrew Johnson\u27s Civil War and Reconstruction
Examining Lincolnâs Successor
In 1987, Paul Bergeron took over the editorship of the Papers of Andrew Johnson from his colleagues at the University of Tennessee at Knoxville, LeRoy P. Graf and Ralph W. Haskins. Thirteen years later, in 2000, he brought the project to completion after pu...
EVALUASI TEKNIK BERMAIN BOLA BASKET PADA RNPELAJAR SMP NEGERI 1 LADANG RIMBA RNTAHUN 2013/2014
Challenges associated with high-solid anaerobic digestion
Biogas production through anaerobic digestion (AD) enables use of resources contained in organic waste streams to produce renewable energy and biofertiliser. For treatment of organic material with high total solids content, high-solid anaerobic digestion (HSD) reduces the need for dilution, but has not been as extensively studied as more conventional wet AD processes. The low dilution rate in HSD involves a high risk of accumulation of toxic substances, such as ammonia, a well-known inhibitor of AD processes. Monitoring of thermophilic HSD systems in this thesis indicated disturbances, with associated accumulation of propionate and changes in microbial population at ammonium-nitrogen concentrations >4 g/L. Continuous HSD processes are typically run in reactors of plug-flow type (PFR), characterised by a concentration gradient of organic material and degradation products from inlet to outlet. This thesis demonstrated challenges in obtaining plug-flow dynamics and phase-separated microbial communities in PFRs both at laboratory and industrial scale. Serial digestion systems, which have characteristics similar to plug-flow behaviour, improved methane yield and protein degradation significantly when food waste was digested in wet conditions. A down-scaling study of an industrial-scale HSD process showed that similar process performance and yield could be obtained in laboratory-scale PFRs, but also that HSD experiments can be carried out in completely stirred-tank reactors (CSTR) usually used for wet materials. Thus the work in this thesis addressed some of the challenges associated with HSD and demonstrated that laboratory-scale studies can be used for future process optimisation trials
The Long Shadow of the Civil War: Southern Dissent and Its Legacies
Family and Dissent in the South during and after the Civil War Victoria Bynumâs new book expands on her 2002 study, The Free State of Jones: Mississippiâs Longest Civil War, because it supplements the resistance against the Confederate government in southern Mississippi with two...
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