Variations in Models of Intraindividual Variation

2004 ◽  
Vol 49 (1) ◽  
pp. 102-105
Author(s):  
Donald Hedeker
Keyword(s):  
Intraindividual Variation

scholarly journals No intraindividual variation of disomy rate in sperm samples

2002 ◽  
Vol 47 (10) ◽  
pp. 0539-0542 ◽  
Author(s):  
A. Amiel ◽  
B. Bartoov ◽  
D. Pevsner ◽  
F. Sardos-Albertini ◽  
M. D. Fejgin
Keyword(s):  
Intraindividual Variation

Reproducibility of osmotic and nonosmotic tests of vasopressin secretion in men

1991 ◽  
Vol 260 (3) ◽  
pp. R533-R539 ◽  
Author(s):  
C. J. Thompson ◽  
P. Selby ◽  
P. H. Baylis
Keyword(s):  
Blood Glucose ◽  
Linear Regression ◽  
Hypertonic Saline ◽  
Linear Regression Analysis ◽  
Plasma Osmolality ◽  
Saline Infusion ◽  
Intraindividual Variation ◽  
Insulin Tolerance ◽  
Vasopressin Secretion ◽  
Hypertonic Saline Infusion

We have studied the reproducibility of the thirst and arginine vasopressin (AVP) responses to osmotic and hypoglycemic stimulation in healthy volunteers undergoing repeat hypertonic (855 mmol/l) saline infusion and insulin tolerance tests (ITTs). Hypertonic saline infusion caused similar mean rises in plasma osmolality, AVP, and thirst on each occasion. Linear-regression analysis defined close relationships between the slopes (r = +0.72, P less than 0.05) and the abscissal intercepts (r = +0.89, P less than 0.001) of the regression lines relating plasma osmolality (Posmol) and plasma AVP (PAVP), and the group intraindividual component of the variance for the slopes and intercepts was 7 and 0.6%, respectively. There were close correlations between the slopes (r = +0.79, P less than 0.02) and the intercepts (r = +0.84, P less than 0.01) of the regression lines relating Posmol and thirst, and group intraindividual component of the variance was 14 and 0.7%, respectively. Hypertonic saline infusion was infused on four occasions in four subjects, and the results showed that the linear regression lines relating PAVP and Posmol and thirst and Posmol were reproducible within an individual. There were similar falls in blood glucose and elevations in PAVP in both ITTs. No relationship was defined between the fall in blood glucose and either the rise in PAVP or the area under the AVP curve (AUC). The intraindividual component of the variance for the rise in AVP and the AUC was 77 and 22.5%, respectively. The AVP and thirst responses to osmotic stimulation are highly reproducible, but there is considerable intraindividual variation in the AVP response to hypoglycemia.

A modified sonographic technique for assessment of gastric emptying of liquid

2003 ◽  
Vol 44 (3) ◽  
pp. 340-342 ◽  
Author(s):  
J. F. Pedersen
Keyword(s):  
Gastric Emptying ◽  
Repeated Measurements ◽  
Intraindividual Variation ◽  
Ultrasound Technique ◽  
Liquid Meal ◽  
Ultrasound Monitoring ◽  
Gastric Emptying Time ◽  
The Mean ◽  
Antral Area ◽  
Emptying Time

Purpose: Ultrasound scanning is replacing scintigraphy in studies of gastric emptying of liquid, but both have considerable day-to-day variability. This study describes a modified ultrasound technique for assessing gastric emptying of liquid, and evaluates the inter- and intraindividual variation in emptying time. Material and Methods: On different days, each of 12 healthy volunteers had meals of 350 ml broth. The antral area was measured at sonography 5 times before the meal as a baseline, and every 1–4 min after the meal. The time until the antral area had decreased to 150% of baseline (T150) was determined and used as surrogate expression of gastric emptying time. Results: The mean T150 for a broth meal was 12.6 min (range 5–21) and 13.5 min (6–23) (first and second meal, respectively). The standard deviation of the differences between the 12 pairs of repeated measurements was 3.1 min and the coefficient of variation was 24%. Conclusion: Ultrasound monitoring of antral size after a liquid meal is a well suited method for assessing gastric emptying of liquid.

Chromosome Banding in Amphibia. XXXV. Highly Mobile Nucleolus Organizing Regions in Craugastor fitzingeri (Anura, Craugastoridae)

2017 ◽  
Vol 152 (4) ◽  
pp. 180-193 ◽  
Author(s):  
Michael Schmid ◽  
Claus Steinlein ◽  
Wolfgang Feichtinger ◽  
Indrajit Nanda
Keyword(s):  
Chromosome Banding ◽  
Cytogenetic Study ◽  
Variable Number ◽  
28S Rdna ◽  
Fish Analysis ◽  
Intraindividual Variation ◽  
Length Polymorphisms ◽  
Somatic Tissues

A 7-year cytogenetic study on the leaf litter frog Craugastor fitzingeri from Costa Rica and Panama revealed the existence of highly mobile nucleolus organizing regions (NORs) in their genomes. Silver (Ag)-staining of the active NORs demonstrated an exceptional interindividual pattern of NOR distribution at the telomeres of the chromosomes. All individuals examined showed a different and specific NOR location in their karyotypes. Furthermore, intraindividual variation in the NOR sites was found. This observation suggested the existence of mobile NORs in C. fitzingeri. Confirmation of this phenomenon was possible by systematic FISH analysis using an 18S + 28S rDNA probe. The extremely variable number and position of the NORs in C. fitzingeri is best explained by highly mobile NORs that move freely between the telomeres of the chromosomes. These transpositions must occur preferentially in premeiotic, meiotic, or postmeiotic stages, but also at a lower incidence in the somatic tissues of the animals. It is hypothesized that transposable (mobile) elements are closely linked to the NORs or are inserted into the major 18S + 28S rDNA spacers of C. fitzingeri. When such transposable elements spread by transpositions, they can carry with them complete or partial NORs. The present study provides detailed information on various differential chromosome banding techniques, in situ hybridization experiments, chromosomal hypermethylation patterns, determination of the genome size, and analyses of restriction fragment length polymorphisms of the DNA.

Day-To-Day Variability of Protein Transport Used as a Method for Analyzing Peritoneal Permeability in CAPD

1991 ◽  
Vol 11 (3) ◽  
pp. 217-223 ◽  
Author(s):  
Désirée Zemel ◽  
Raymond T. Krediet ◽  
Gerardus C.M. Koomen ◽  
Dirk G. Struijk ◽  
Lambertus Arisz
Keyword(s):  
Surface Area ◽  
Structural Changes ◽  
Protein Transport ◽  
Intrinsic Permeability ◽  
Effective Surface Area ◽  
Intraindividual Variation ◽  
Effective Surface ◽  
Peritoneal Surface ◽  
Beta 2 ◽  
Beta 2 Microglobulin

The transperitoneal transport of macromolecules is dependent on both effective peritoneal surface area and intrinsic permeability of the peritoneum. For passage of small solutes, the effective surface area is the main determinant. We hypothesized that day-to-day variations in peritoneal clearances are caused by changes in the effective surface area and not in the intrinsic permeability. Four CAPD {continuous ambulatory peritoneal dialysis) patients without peritonitis were investigated on 28 consecutive days. Concentrations of beta-2-microglobulin, albumin, IgG, and alpha-2-macroglobulin were determined daily in dialysate {night bags) and weekly in serum. Clearances and their coefficients of variation were calculated. Mean coefficients of the intraindividual variation of protein clearances increased, the higher the molecular weight: they ranged from 12% for beta-2microglobulin clearance to 22% for alpha-2-macroglobulin clearance. Correlations were present between the clearances of albumin, IgG, and alpha-2-macroglobulin, but not between any of these and beta-2-microglobulin clearance. In all patients, protein clearance {C) was a power function of the free diffusion coefficient in water {D) according to the equation: C=a. Db in which b represents the restriction coefficient of the peritoneum, and thus intrinsic permeability. The coefficient of variation of the restriction coefficient was low (range 4–6%). This supports our assumption that the intrinsic permeability is fairly constant on the short term. Day-to-day variations in protein clearances are thus mainly caused by alterations in the effective peritoneal surface area. Longterm follow-up of the restriction coefficient in individual patients might identify those at risk for the development of structural changes in the peritoneal membrane.

scholarly journals Circadian rhythms and second language performance

2017 ◽  
Vol 7 (1) ◽  
pp. 47-60
Author(s):  
Kees De Bot ◽  
Fang Fang
Keyword(s):  
Second Language ◽  
Language Learning ◽  
Lexical Access ◽  
Language Processing ◽  
Language Performance ◽  
Intraindividual Variation ◽  
The Hours ◽  
L1 And L2 ◽  
The Impact ◽  
Second Language Performance

Human behavior is not constant over the hours of the day, and there are considerable individual differences. Some people raise early and go to bed early and have their peek performance early in the day (“larks”) while others tend to go to bed late and get up late and have their best performance later in the day (“owls”). In this contribution we report on three projects on the role of chronotype (CT) in language processing and learning. The first study (de Bot, 2013) reports on the impact of CT on language learning aptitude and word learning. The second project was reported in Fang (2015) and looks at CT and executive functions, in particular inhibition as measured by variants of the Stroop test. The third project aimed at assessing lexical access in L1 and L2 at preferred and non-preferred times of the day. The data suggest that there are effects of CT on language learning and processing. There is a small effect of CT on language aptitude and a stronger effect of CT on lexical access in the first and second language. The lack of significance for other tasks is mainly caused by the large interindividual and intraindividual variation.

Sign in / Sign up

Export Citation Format

Share Document