The Jackknife--A Review

Miller, Rupert G.

doi:10.2307/2334280

Cited by 658 publications

(696 citation statements)

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“…The random effects were predicted using the adjusted unbiased prediction (AUP) method (Zhu and Weir, 1996). Standard errors of the statistics were obtained by the jackknife procedures (Miller, 1974;Zhu and Weir, 1996) and a two-tail t-test was performed for testing the significance of parameters obtained. The model was also recalculated considering genotype as fixed factor for mean performance accession comparison computing using LSD method at ˛ = 0.05.…”

Section: Discussionmentioning

confidence: 99%

Exploring alternative germplasm for the development of stable high vitamin C content in tomato varieties

Leiva-Brondo

Valcárcel

Cortés-Olmos

et al. 2012

Scientia Horticulturae

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a b s t r a c tThe genotypic potential for high l-ascorbic acid content of 15 accessions of S. lycopersicon and S. pimpinellifolium has been evaluated in three environments, including open-air and glasshouse cultivation and two localities. The environmental effect on l-ascorbic acid accumulation was highly genotype-dependant and the variance ascribed to the G×E environment was similar in importance to that ascribed to genotype. The variation found within accession might be ascribed to microenvironmental effects associated with temperature changes and oxidative stress or population variability. Several accessions with high genotypic values ( +G) have been identified. Among them, accession PI365959 of S. pimpinellifolium, showed a genotypic value of 293.8 mg kg −1 , statistically significant higher (P < 0.05) than the genotypic potential of controls reported to have high l-ascorbic content (CDP4777, 115.0 mg kg −1 ). It also showed positive G×E interactions, with a relatively high stability. Accession LA1423 of S. lycopersicon var. cerasiforme, despite being less stable, had also high genotypic values for l-ascorbic acid accumulation (197.4 mg kg −1 ). This germplasm will be of great interest for the development of new tomato cultivars targeted to added-value markets appreciating nutritional or functional quality. The close relationship of the selected material with the cultivated tomato will enable an efficient and rapid exploitation of their potential in breeding programmes.

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Section: Discussionmentioning

confidence: 99%

Exploring alternative germplasm for the development of stable high vitamin C content in tomato varieties

Leiva-Brondo

Valcárcel

Cortés-Olmos

et al. 2012

Scientia Horticulturae

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“…There are good reasons to suspect that the jackknife approach (e.g., Efron, 1981;Jackson, 1986;Miller, 1974;Mosteller & Tukey, 1977) may provide more accurate estimates of latency differences than the approach of scoring of single-participant waveforms. With the jackknife approach, latencies are scored for each of n grand average waveforms, with each of the grand average waveforms computed from a subsample of n À 1 of the n individual participants (i.e., each participant is omitted from one of the subsample grand averages).…”

Section: The Jackknife Approachmentioning

confidence: 99%

Measurement of ERP latency differences: A comparison of single‐participant and jackknife‐based scoring methods

et al. 2007

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We used computer simulations to evaluate different procedures for measuring changes in the onset latency of a representative range of event-related components (the auditory and visual N1, P3, N2pc, and the frequency-related P3 difference wave). These procedures included several techniques to determine onset latencies combined with approaches using both single-participant average waveforms and jackknife-subsample average waveforms. In general, the jackknife-based approach combined with the relative criterion technique or combined with the fractional area technique (J.C. Hansen & S.A. Hillyard, 1980; S.J. Luck, 2005) provided the most accurate method and the greatest statistical power, with no inflation of Type I error rate.Descriptors: ERP latency, Jackknife, N1, P3, N2pc, Frequency-related P3Research using event-related potentials (ERPs) often focuses on differences in amplitudes as well as differences in latencies of ERP components. However, for both measurements there are several scoring methods, and quite often researchers have to decide rather arbitrarily which method might be most appropriate. In this article we compare several methods for determining ERP latency differences. To evaluate the methods we ran computer simulations based on data of five ERP components: the visual N1, the auditory N1, the P3 (hereafter used to mean the P3b), the N2pc, and the frequency-related P3 component (infrequent minus frequent difference wave).These five components were chosen because they are very different and representative of a broad range of components, as is apparent from the following brief review of these components. The N1 components (visual, auditory) are relatively early components, strongly influenced by physical properties of the stimulus. They are characterized by a clear onset and a sharply increasing amplitude, but clearly reflect different underlying neural generators. In contrast, the P3 is a late component that is relatively insensitive to the physical properties of the stimulus (with the exception of tone intensity; see Covington & Polich, 1996), but is influenced by probabilities, expectations, and resource allocation (see Johnson, 1986). Quite often the P3 does not show a clear onset, and its peak latency is difficult to determine because the component has a wide temporal extension without a sharp peak. The N2pc and frequency-related P3, for their part, are measured from difference waves that are obtained by subtracting ERP waveforms computed at different electrode sites or at same electrode sites but in different experimental conditions. The N2pc is an index of the allocation of visualspatial attention and is isolated by subtracting the ERP at posterior electrode sites ipsilateral to an attended item from the ERP at the corresponding contralateral electrode site, whereas the frequency-related P3 is isolated by subtracting the ERP elicited by frequent targets from the ERP elicited by infrequent targets.For all components, researchers are often interested in estimating the latency differences a...

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“…The entire sample was used for the creation of the model, and cross-validation was performed by using a jackknife approach, 23 dividing the whole sample into 10 mutually exclusive groups by random method; 10 different regression models were estimated, with each model excluding one group; each model was used to calculate predictions for the excluded group. Predicted risks for individual patients from the excluded groups were then compared with predictions based on the entire sample.…”

Section: Discussionmentioning

confidence: 99%

Relationship between mortality and first-day events index from routinely gathered physiological variables in ICU patients

Rivera-Fernández

Castillo-Lorente

Nap

et al. 2012

Medicina Intensiva (English Edition)

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Objective: To test the hypothesis that the degree and duration of alterations in physiological variables routinely gathered by intensive care unit (ICU) monitoring systems during the first day of admission to the ICU, together with a few additional routinely recorded data, yield information similar to that obtained by traditional mortality prediction systems. Design: A prospective observational multicenter study (EURICUS II) was carried out. Setting: Fifty-five European ICUs. Patients: A total of 17,598 consecutive patients admitted to the ICU over a 10-month period. Interventions: None. Main variables of interest:Hourly data were manually gathered on alterations or ''events'' in systolic blood pressure, heart rate and oxygen saturation throughout ICU stay to construct an events index and mortality prediction models. Results: The mean first-day events index was 6.37 ± 10.47 points, and was significantly associated to mortality (p < 0.001), with a discrimination capacity for hospital mortality of 0.666 (area under the ROC curve). A second index included this first-day events index, age, preadmission location, and the Glasgow coma score. A model constructed with this second index plus diagnosis upon admission was validated by using the Jackknife method (Hosmer-Lemeshow, H = 13.8554, insignificant); the area under ROC curve was 0.818. Conclusions: A prognostic index with performance very similar to that of habitual systems can be constructed from routine ICU data with only a few patient characteristics. These results may serve as a guide for the possible automated construction of ICU prognostic indexes. © 2011 Elsevier España, S.L. and SEMICYUC. All rights reserved. * Corresponding author. E-mail address: encarnacion.castillo.sspa@juntadeandalucia.es (E. Castillo-Lorente). Relationship between mortality and first-day events index 635 PALABRAS CLAVE Cuidados Intensivos; Cuidados Críticos; Índices de gravedad; EventosRelación entre la mortalidad y el índice de eventos del primer día de estancia a partir de variables fisiológicas recogidas durante la monitorización rutinaria de pacientes de la UCI Resumen Objetivo: Comprobar si el grado y duración de las alteraciones en las variables fisiológicas recogidas en la monitorización rutinaria en UCI durante el primer día de estancia, junto con pocos datos adicionales, proporcionan información similar a la obtenida con los sistemas tradicionales de predicción de mortalidad. Diseño: Estudio observacional, prospectivo y multicéntrico (EURICUS-II). Ámbito: 55 UCIs de Europa. Pacientes: 17.598 pacientes consecutivos, ingresados durante 10 meses. Intervenciones: ninguna. Variables de interés principales: se recogieron manualmente datos horarios sobre alteraciones o ''eventos'' en la presión arterial sistólica, frecuencia cardiaca y saturación de oxígeno, para construir un índice basado en estos eventos y un modelo de predicción de mortalidad. Resultados: El índice de eventos el primer día fue 6,37 ± 10,47 puntos y se asoció significativamente con la mortalidad (p < 0,001)...

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The Jackknife--A Review

Cited by 658 publications

References 0 publications

Exploring alternative germplasm for the development of stable high vitamin C content in tomato varieties

Exploring alternative germplasm for the development of stable high vitamin C content in tomato varieties

Measurement of ERP latency differences: A comparison of single‐participant and jackknife‐based scoring methods

Relationship between mortality and first-day events index from routinely gathered physiological variables in ICU patients

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