885 research outputs found
Time Series Forecasting: The Case for the Single Source of Error State Space
The state space approach to modelling univariate time series is now widely used both in theory and in applications. However, the very richness of the framework means that quite different model formulations are possible, even when they purport to describe the same phenomena. In this paper, we examine the single source of error [SSOE] scheme, which has perfectly correlated error components. We then proceed to compare SSOE to the more common version of the state space models, for which all the error terms are independent; we refer to this as the multiple source of error [MSOE] scheme. As expected, there are many similarities between the MSOE and SSOE schemes, but also some important differences. Both have ARIMA models as their reduced forms, although the mapping is more transparent for SSOE. Further, SSOE does not require a canonical form to complete its specification. An appealing feature of SSOE is that the estimates of the state variables converge in probability to their true values, thereby leading to a formal inferential structure for the ad-hoc exponential smoothing methods for forecasting. The parameter space for SSOE models may be specified to match that of the corresponding ARIMA scheme, or it may be restricted to meaningful sub-spaces, as for MSOE but with somewhat different outcomes. The SSOE formulation enables straightforward extensions to certain classes of non-linear models, including a linear trend with multiplicative seasonals version that underlies the Holt-Winters forecasting method. Conditionally heteroscedastic models may be developed in a similar manner. Finally we note that smoothing and decomposition, two crucial practical issues, may be performed within the SSOE framework.ARIMA, Dynamic Linear Models, Equivalence, Exponential Smoothing, Forecasting, GARCH, Holt's Method, Holt-Winters Method, Kalman Filter, Prediction Intervals.
Low-energy total diet replacement intervention in patients with type 2 diabetes mellitus and obesity treated with insulin: a randomized trial
OBJECTIVES: The management of patients with long-standing type 2 diabetes and obesity receiving insulin therapy (IT) is a substantial clinical challenge. Our objective was to examine the effect of a low-energy total diet replacement (TDR) intervention versus standardized dietetic care in patients with long-standing type 2 diabetes and obesity receiving IT. RESEARCH DESIGN AND METHODS: In a prospective randomized controlled trial, 90 participants with type 2 diabetes and obesity receiving IT were assigned to either a low-energy TDR (intervention) or standardized dietetic care (control) in an outpatient setting. The primary outcome was weight loss at 12 months with secondary outcomes including glycemic control, insulin burden and quality of life (QoL). RESULTS: Mean weight loss at 12 months was 9.8 kg (SD 4.9) in the intervention and 5.6 kg (SD 6.1) in the control group (adjusted mean difference -4.3 kg, 95% CI -6.3 to 2.3, p<0.001). IT was discontinued in 39.4% of the intervention group compared with 5.6% of the control group among completers. Insulin requirements fell by 47.3 units (SD 36.4) in the intervention compared with 33.3 units (SD 52.9) in the control (-18.6 units, 95% CI -29.2 to -7.9, p=0.001). Glycated Hemoglobin (HbA1c) fell significantly in the intervention group (4.7 mmol/mol; p=0.02). QoL improved in the intervention group of 11.1 points (SD 21.8) compared with 0.71 points (SD 19.4) in the control (8.6 points, 95% CI 2.0 to 15.2, p=0.01). CONCLUSIONS: Patients with advanced type 2 diabetes and obesity receiving IT achieved greater weight loss using a TDR intervention while also reducing or stopping IT and improving glycemic control and QoL. The TDR approach is a safe treatment option in this challenging patient group but requires maintenance support for long-term success. TRIAL REGISTRATION NUMBER: ISRCTN21335883
Comprehensive behavioral testing in the R6/2 mouse model of Huntington's disease shows no benefit from CoQ10 or minocycline
Previous studies of the effects of coenzyme Q10 and minocycline on mouse models of Huntington’s disease have produced conflicting results regarding their efficacy in behavioral tests. Using our recently published best practices for husbandry and testing for mouse models of Huntington’s disease, we report that neither coenzyme Q10 nor minocycline had significant beneficial effects on measures of motor function, general health (open field, rotarod, grip strength, rearing-climbing, body weight and survival) in the R6/2 mouse model. The higher doses of minocycline, on the contrary, reduced survival. We were thus unable to confirm the previously reported benefits for these two drugs, and we discuss potential reasons for these discrepancies, such as the effects of husbandry and nutrition
Linking soil moisture status of winter sports pitches to measures of playing quality
A review of traction and hardness Performance Quality Standard tests highlighted significant relationships with soil and grass factors. Inadequate guidance to achieve test results through pitch management means that management practices can not focus on injury prevention or playing quality. A clear link between factors that can be managed by Groundsmen and the traction and hardness tests is required. The concept of effective stress significantly linked moisture status to soil strength in the laboratory. Penetration resistance was shown to be complex and affected by grass roots and bulk density, which prevented a single model encompassing all soil types to be established. Prediction of traction and hardness used grass and soil factors and varied according to soil type and wet or dry test conditions. In situ tests showed no variation due to pitch test position and as sand content increased, prediction became less reliable. A decision support model used the regression results to provide Groundsmen with the ability to monitor pitch quality in real-time. Effective stress successfully linked moisture status and strength although in situ verification is required. Regression analysis and the decision support model will assist Groundsmen in managing pitches while targeting playing quality. Further research to understand how management practices impact on quality and to understand the link between injury rates and type, and the results of traction and hardness tests is required. This knowledge will enable a company to simultaneously differentiate itself from competition and create a barrier to potential entrants.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Having the Right Tool for the Right Job: Results of an Incentive verses Non-Incentive Weight-loss Program
Article: INTRODUCTION Health promotion or "Wellness" programs have been identified as a means of promoting positive behavior change in the general population, and have become an increasingly attractive value-added benefit in settings such as the worksite, medical and community centers, and universities. As such, one of the most consistently popular choices to effect positive behavior change strategies into a persons lifestyle are weight loss programs. There are several reasons why a weight loss program can provide positive benefits: Weight loss is of great personal interest to many people, thus it can be an attractive fringe benefit at an employment site, Weight loss programs may lessen health expenditures by reducing costs due to weight-related conditions, i.e.; diabetes and hypertension, and, Weight loss may improve overall satisfaction in personal life areas such as self-image and self-esteem. Given these potential benefits, challenges still exist for health professionals obtaining consistent participation and retention by participants engaged in programs such as weight loss. One way to attract people to take part in a program is through the use of incentives. Traditionally, incentives have been offered either up front to encourage sign-up and participation, at various stages of the program to recognize positive behavior change, and/or upon completion of the program. Reports on the use of incentives for participation range from team competitions, money, gifts, and flexible time benefits, among others. Weight loss competitions in the workplace have reported nearly double the attrition and half the weight loss found compared to similar competitions in a clinical setting
Water table control for rice production in Ghana
An investigation has been undertaken to determine the consequence of using water table control for lowland rice production by growing rice varieties Azucena and IR36 in sand cores under a controlled environment in a series of experiments in which the water table was held at fixed levels. Each experiment had a duration of six weeks and in all, four treatments were used: (a) water table at a depth of 30 cm below the surface, (b) water table at a depth of 15 cm below the surface, (c) saturated sand and (c) flooded sand. Growth under the two water table depths compared favourably with the flooded and saturated conditions, with plants under the water table control treatments in some cases performing better in terms of plant performance than the saturated or flooded. Plant growth parameters measured were: Tiller number, root dry mass, shoot dry mass, rooting depth, total root length and plant height. Other parameters measured are: Solution nitrogen concentration, redox potential, growth medium temperature and pH levels. When IR36 was used the total root length, number of roots and tiller numbers were significantly greater for the plants in the saturated treatment but there were no significant differences in root mass, shoot mass, and shoot length with regards to water depth. When Azucena variety was used, the 15 cm treatment had the highest shoot mass in addition to the highest tiller numbers. In other parameters, the 15 cm treatment did not show a significant difference to the saturated treatment. The 30 cm treatment performed least well in all parameters measured. Plants under the flooded treatment had a significantly greater root dry mass, shoot dry mass and tiller number than the others. The plants grown under 15 cm water table depth had the least root mass. Tiller numbers for the plants under the 30 cm water table depth were greater than those under the 15 cm water table depth. Differences in plant development parameters generally appeared only after the fourth week. The data suggest that irrespective of the water treatment used, plant development trends remain the same indicating that in the first four weeks of rice growth much less water can be used without affecting plant development. Where Azucena and IR36 were both used the data suggest that water table control might be suitable for both varieties of rice. Differences in the amount of nitrogen present were seen to have had an impact on growth. Varying the form of nitrogen applied did not alter growth parameters to any appreciable extent implying that supply of nitrogen is more important than the form of nitrogen used. The effect of root properties and NH4+ transport through the soil on N uptake under different water regimes has been modelled. The model adequately predicted the root length densities required to explain N uptake rates. It is shown that root length densities increase with decreasing moisture content, allowing larger root length densities to compensate for low nutrient transport rates and although diffusion of nutrients increased with increasing moisture levels, nutrient uptake rates did not follow the same pattern. Rooting length densities and transport of nutrients are not shown to limit uptake of nutrients under any of the water treatments imposed. The feasibility of using water table control in the inland valleys of Ghana was also investigated by simulating the depth of the water table required in the dry season of the years 1996 and 1997. A comparison of water use under water table control and flooding irrigation showed that water savings were possible suggesting that water table control is feasible and beneficial in the inland valleys of Ghana.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Derivation, validation, and comparison of a new prognostic scoring system for acute lower gastrointestinal bleeding
\ua9 2023 The Authors. DEN Open published by John Wiley & Sons Australia, Ltd on behalf of Japan Gastroenterological Endoscopy Society.Objectives: Lower gastrointestinal bleeding is a common presentation with little data concerning risk factors for adverse outcomes. The aim was to derive and validate a scoring system to stratify risk in lower gastrointestinal bleeding and compare it to the Oakland score. Methods: A total of 2385 consecutive patients (mean age 65 years, 1140 males) were used to derive the score using multivariate logistic regression modeling then internally and externally validated. The Oakland score was applied and area under receiver operating characteristic (AUROC) curves were calculated and compared. A score of <1 was compared with an Oakland score of <9 to assess 30-day rebleeding and mortality rates. Results: Rebleeding was associated with age, inpatient bleeding, syncope, malignancy, tachycardia, hypotension, lower hemoglobin and mortality with age, inpatient bleeding, liver/gastrointestinal disease, tachycardia, and hypotension. The area under the receiver operating characteristic curves was 0.742 for rebleeding and 0.802 for mortality. A score <1 was associated with rebleeding (0.0%–2.2%) and mortality (0%). The Oakland score had a significantly lower area under the receiver operating characteristic curve for rebleeding of 0.687 but not for mortality; 0.757. A score <1 was associated with a lower 30-day rebleeding risk compared to an Oakland score <9 (4/379 vs. 15/355, p = 0.009) but not mortality (0/365 vs. 1/355, p = 0.493). Conclusions: Our score predicts 30-day rebleeding and mortality rate with low scores associated with very low risk. The Aberdeen score is superior to the Oakland score for predicting rebleeding. Prospective evaluation of both scores is required
The Maine Lung Cancer Coalition: A Statewide, Multi-Sector Partnership to Improve Evidence-Based Lung Cancer Prevention & Screening
MLCC has two primary goals:
1. Engage and educate about evidence based lung cancer prevention and screening practices
2. Develop, implement, and evaluate innovative programs to increase access to prevention, screening, and treatment services for all Mainershttps://knowledgeconnection.mainehealth.org/lambrew-retreat-2021/1051/thumbnail.jp
Using the cre-lox recombination system to assess functional impairment caused by amino acid substitutions in yeast proteins
A method was developed to assess the functional significance of a sequence motif in yeast Upf3p, a protein required for nonsense-mediated mRNA decay (NMD). The motif lies at the edge of the Upf3p-Upf2p interaction domain, but at the same time resembles the canonical leucine-rich nuclear export sequence (NES) found in proteins that bind Crm1p exportin. To test the function of the putative NES, site-directed mutations that cause substitutions of conserved NES-A residues were first selected to identify hypermorphic alleles. Next, a portable Crm1p-binding NES from HIV-1 Rev protein that functions in yeast was fused en masse to the C-terminus of variant Upf3 proteins using loxP sites recognized by bacterial cre-recombinase. Finally, variant Upf3-Rev proteins that were functional in NMD were selected and examined for the types of amino acid substitutions present in NES-A. The mutational analysis revealed that amino acid substitutions in the Upf3 NES impair both nuclear export and the Upf2p-Upf3p interaction, both of which are required for Upf3p to function in NMD. The method described in this report could be modified for the genetic analysis of a variety of portable protein domains
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