Search results for "Linear Models"
showing 10 items of 440 documents
Perceived Burden among Spouse, Adult Child and Parent Caregivers
2018
Aims To identify what factors are associated with the caregiver burden of spouse caregivers, adult child caregivers, and parent caregivers. Background Caregivers often feel stressed and perceive caregiving as a burden. The caregiver burden has been little studied from the perspective of the personal relationship between caregiver and care recipient. Design Cross-sectional study. Methods A random sample of 4,000 caregivers in Finland was drawn in 2014 and those who remained either spouse, adult child, or parent caregivers at data collection were included in the analysis (N = 1,062). Data collection included recipients' characteristics. Caregivers' perceived burden was measured using the Care…
Effects of comprehensive geriatric intervention on physical performance among people aged 75 years and over.
2012
Background and aims: We studied the effects of comprehensive geriatric assessment and multifactorial intervention on physical performance among older people. Methods: In a 3-year geriatric development project with an experimental design, 668 participants aged 75–98 were assigned to intervention (n=348) or control (n=320) groups. The intervention group received comprehensive geriatric assessment with an individually targeted intervention for 2 years. The outcome measures—performance in the Timed Up-and-Go (TUG), 10-meter walking and Berg Balance Scale tests 2 were gathered annually during the intervention and the 1-year follow-up after it. Results: With linear mixed models, over the 2-year i…
Physical performance in relation to menopause status and physical activity
2018
Objective: The aim of this study was to examine differences in physical performance (muscle power, muscle strength, aerobic capacity, and walking speed) across menopausal stages and potential of leisure physical activity (PA) to modify the impact of menopause on physical performance. Methods: In this cross-sectional study, women aged 47 to 55 were randomly selected from the Finnish National Registry and categorized as premenopausal (n ¼ 233), perimenopausal (n ¼ 381), or postmenopausal (n ¼ 299) based on serum concentrations of follicle-stimulating hormone and bleeding diary. Physical performance was measured by knee extension force, handgrip force, vertical jumping height, maximal walking …
Antimicrobial Activity Characterization in a Heterogeneous Group of Compounds
1998
In this work we carry out a study of pattern recognition to detect the microbiological activity in a group of heterogeneous compounds. The structural descriptors utilized are the topological connectivity indexes. The methods followed are stepwise linear discriminant analysis (linear analysis) and artificial neural network (nonlinear analysis). Although both methods are appropriate to differentiate between active and inactive compounds, the artificial neural network is, in this case, more adequate, since it shows in a test set a prediction success of 98%, versus 92% obtained with linear discriminant analysis.
Unconventional monetary policy reaction functions: evidence from the US
2020
Abstract We specify unconventional monetary policy reaction functions for the Fed using linear and nonlinear econometric frameworks. We find that nonstandard policy measures are largely driven by the dynamics of inflation and the output gap, with the effect being particularly strong during QE rounds. Moreover, we uncover the presence of asymmetry and regime dependence in central bank’s actions since the global financial crisis, especially concerning the response of the term spread and the shadow short rate to the growth rate of central bank reserves. From a policy perspective and given the lack of a systematic response of monetary policy to asset price growth in nonstandard times, our findi…
Analysis of insecticides in honey by liquid chromatography–ion trap-mass spectrometry: Comparison of different extraction procedures
2010
The feasibility of different extraction procedures was tested and compared for the determination of 12 organophosphorus and carbamates insecticides in honey samples. In this sense, once the samples were pre-treated - essentially dissolved in hot water by stirring - and before they could be analyzed by liquid chromatography-ion trap-second stage mass spectrometry (LC-MS(2)), four different approaches were studied for the extraction step: QuEChERS, solid-phase extraction (SPE), pressurized liquid extraction (PLE) and solid-phase microextraction (SPME). The main aim of this work was to maximise the sensitivity of pesticides and to minimise the presence of interfering compounds in the extract. …
Solid-phase microextraction-liquid chromatography-mass spectrometry applied to the analysis of insecticides in honey
2007
An approach based on solid-phase microextraction-liquid chromatography-mass spectrometry (SPME-LC-MS) has been developed for determining 12 insecticides (bromophos ethyl, chlorpyrifos methyl, chlorpyrifos ethyl, diazinon, fenoxycarb, fonofos, phenthoate, phosalone, pirimiphos methyl, profenofos, pyrazophos, and temephos) in honey. The influence of several parameters on the efficiency of the SPME was systematically investigated. Under optimal conditions, the procedure provided excellent linearity (>0.990), detection and quantification limits (between 0.001 and 0.1 microg g(-1) and between 0.005 and 0.5 microg g(-1), respectively), and precision (<19% at the quantification limits and from 6 t…
Internal Test Sets Studies in a Group of Antimalarials
2006
Topological indices have been applied to build QSAR models for a set of 20 an- timalarial cyclic peroxy cetals. In order to evalua te the reliability of the proposed linear models leave-n-out and Internal Test Sets (ITS) approaches have b een considered. The pro- posed procedure resulted in a robust and consensued prediction equation and here it is shown why it is superior to the employed standard c ross-validation algorithms involving multilinear regression models.
Evaluation of furanocoumarins from seeds of the wild parsnip (Pastinaca sativa L. s.l.).
2018
Abstract Although the wild parsnip (Pastinaca sativa L. s.l.) fruits are known to contain linear and angular furanocoumarins, the individual components of the seeds have not been fully identified and quantitated, and, in the case of immature seeds, reported. In view of this, the main furanocoumarin compounds were extracted using pyridine, and were isolated using semi-preparative high-performance liquid chromatography. The structural elucidation of isolated compounds was done based on detailed spectral analysis conducted by liquid chromatography–electrospray ionization–mass spectrometry (LC–ESI/MS), 1H and 13C NMR and, where possible, by gas chromatography–mass spectrometry (GC–MS). The quan…
Serum leptin is associated with serum uric acid concentrations in humans.
1999
This cross-sectional study aimed to evaluate the relationship between leptin and the cluster of abnormalities often referred to as the metabolic syndrome. The serum leptin concentration, body mass index (BMI), percent body fat, total fat mass (FM), waist and hip circumference, waist to hip ratio (WHR), prevalence of hypertension, and triglyceride (TG), lipoprotein, and uric acid concentration were determined in 86 type 2 diabetic (n = 59) and healthy (n = 27) subjects. Multiple regression analyses showed that the estimates of total body obesity (BMI, percent body fat, and total FM), sex, and serum uric acid concentration are independently associated with the serum leptin concentration. The …