Search results for "STATISTICS"

One repetition maximum bench press performance: A new approach for its evaluation in inexperienced males and females: A pilot study

2014

Summary The aim of this study was to evaluate a new method to perform the one repetition maximum (1RM) bench press test, by combining previously validated predictive and practical procedures. Eight young male and 7 females participants, with no previous experience of resistance training, performed a first set of repetitions to fatigue (RTF) with a workload corresponding to 1/3 of their body mass (BM) for a maximum of 25 repetitions. Following a 5-min recovery period, a second set of RTF was performed with a workload corresponding to 1/2 of participants’ BM. The number of repetitions performed in this set was then used to predict the workload to be used for the 1RM bench press test using May…

Crop Phenology Retrieval Through Gaussian Process Regression

2021

Monitoring crop phenology significantly assists agricultural managing practices and plays an important role in crop yield predictions. Multi-temporal satellite-based observations allow analyzing vegetation seasonal dynamics over large areas by using vegetation indices or deriving biophysical variables. This study presents a framework for automatic corn phenology characterization based on high spatial and temporal resolution time series. By using the Difference Vegetation Index (DVI) estimated from Sentinel-2 data over Iowa (US), independent phenological models were optimized using Gaussian Processes regression. Their respective performances were assessed based on simulated phenological indi…

Statistical analysis of sensory profiling data. Graphs for presenting results (PCA and ANOVA)

2000

Abstract A principal component analysis is performed to analyse the matrix of median values, with 16 varieties in rows, and all descriptors in columns. Only texture descriptors contribute to the definition of the main axes. Six varieties are identified that score high on mealiness and low on moisture, the 10 other varieties are ordered according to a mashable axis which involves texture descriptors. Next we exclude texture descriptors since the main characteristics are already found, and mealy varieties since they are not suitable for steamed potatoes. A mixed linear model (ANOVA) with random subject effects is then used for each descriptor. Flavour and taste differences are found among the…

Application of replicated difference testing

2000

International audience; In a recent paper, Brockho€ and Schlich (1998, Handling replications in discrimination tests. Food Quality and Preference, 9(5), 303±312) proposed a statistically sound way of handling replications in di€erence testing. In the present paper, this new test is applied to the data obtained in six experiments on non alcoholic beverages, where triangle tests were intensively replicated (between eight and 60 times) with groups of subjects composed of 12±61 students. The paper aims to estimate in these practical situations the extent to which a group of panelists is heterogeneous towards the ability of detecting a sensory di€erence among two products. As the results indicat…

Influence of land-use intensity on the spatial distribution of N-cycling microorganisms in grassland soils

2011

A geostatistical approach using replicated grassland sites (10 m × 10 m) was applied to investigate the influence of grassland management, i.e. unfertilized pastures and fertilized mown meadows representing low and high land-use intensity (LUI), on soil biogeochemical properties and spatial distributions of ammonia-oxidizing and denitrifying microorganisms in soil. Spatial autocorrelations of the different N-cycling communities ranged between 1.4 and 7.6 m for ammonia oxidizers and from 0.3 m for nosZ-type denitrifiers to scales >14 m for nirK-type denitrifiers. The spatial heterogeneity of ammonia oxidizers and nirS-type denitrifiers increased in high LUI, but decreased for biogeochemical …

Scenario-based discrimination of common grapevine varieties using in-field hyperspectral data in the western of Iran

2019

Abstract Field spectroscopy is an accurate, rapid and nondestructive technique for monitoring of agricultural plant characteristics. Among these, identification of grapevine varieties is one of the most important factors in viticulture and wine industry. This study evaluated the discriminatory ability of field hyperspectral data and statistical techniques in case of five common grapevine varieties in the western of Iran. A total of 3000 spectral samples were acquired at leaf and canopy levels. Then, in order to identify the best approach, two types of hyperspectral data (wavelengths from 350 to 2500 nm and 32 spectral indices), two data reduction methods (PLSR and ANOVA-PCA) and two classif…

Screening individual ability to perform descriptive analysis of food products : basic statements and application to a camembert cheese descriptive pa…

1995

A battery of sensory tests is proposed to select potential descriptive panelists. This set of tests is flavor specific. Several abilities are examined: odor and taste recognition, odor memory, discrimination and descriptive capacities. A detailed example of such a battery to select a Camembert cheese descriptive panel is given. The objectives of each test are discussed. Stimuli are chosen to be consistent with the sensory properties which can be perceived in cheese. Score distributions demonstrate the discrimination among candidates for each test. Globally, results show the difficulty to find 20 panelists amongst about a hundred with good scores on each test. The panel leader has to choose …

2016

The Global Burden of Disease, Injuries, and Risk Factor study 2013 (GBD 2013) is the first of a series of annual updates of the GBD. Risk factor quantification, particularly of modifiable risk factors, can help to identify emerging threats to population health and opportunities for prevention. The GBD 2013 provides a timely opportunity to update the comparative risk assessment with new data for exposure, relative risks, and evidence on the appropriate counterfactual risk distribution. Attributable deaths, years of life lost, years lived with disability, and disability-adjusted life-years (DALYs) have been estimated for 79 risks or clusters of risks using the GBD 2010 methods. Risk-outcome p…

Crop Yield Estimation and Interpretability With Gaussian Processes

2021

This work introduces the use of Gaussian processes (GPs) for the estimation and understanding of crop development and yield using multisensor satellite observations and meteo- rological data. The proposed methodology combines synergistic information on canopy greenness, biomass, soil, and plant water content from optical and microwave sensors with the atmospheric variables typically measured at meteorological stations. A com- posite covariance is used in the GP model to account for varying scales, nonstationary, and nonlinear processes. The GP model reports noticeable gains in terms of accuracy with respect to other machine learning approaches for the estimation of corn, wheat, and soybean …

Modélisation du comportement des agriculteurs face au risque dans un modèle de programmation mathématique positive (PMP) à grande échelle

2017

Agricultural production is characterized for being a risky business due to weather variability, market instability, plant diseases as well as climate change and political economy uncertainty. The modelling of risk at farm level is not new, however, the inclusion of risk in Positive Mathematical Programming (PMP) models is particularly challenging. Most of the few existing PMP-risk approaches have been conducted at farm-type level and for a very limited and specific sample of farms. This implies that the modelling of risk and uncertainty at individual farm level and in a large scale system is still a challenging task. The aim of this paper is to formulate, estimate and test a robust methodol…