Dynamics of gastropod infection by first-stage larvae of protostrongylid nematodes — a model

Parasitology ◽  
1993 ◽  
Vol 107 (5) ◽  
pp. 537-544 ◽  
Author(s):  
P. Řezáč ◽  
P. Kindlmann ◽  
I. Dostálková ◽  
E. Holasová
Keyword(s):  
Experimental Design ◽  
Infective Larva ◽  
Snail Infection ◽  
Instantaneous Rate ◽  
Rate Of Penetration ◽  
Susceptibility To Infection ◽  
Species Specific ◽  
Design Factors ◽  
Best Fit ◽  
Penetration Probability

SUMMARYFor the description of the dynamics of snail infection by the 1st-stage larvae of protostrongylid nematodes, Skorping (1988) used the miracidia-snail model (Anderson, 1978). Here it is shown that, in contrast to miracidia, in protostrongylids the instantaneous rate of infection, α, is strongly dependent on the experimental design (factors like host size and size of the experimental arena). With respect to this, Anderson's model is modified by incorporation of the experimental design. The parameter α in its new sense as the rate of penetration (probability that the infective larva will penetrate into the host during a time unit) is shown to remain dependent, although much less so, on the experimental design. Only the inclusion of the assumed effect of mucus, which decreases the rate of penetration, yields a parameter α0 (the initial rate of penetration), which is completely independent of the design of the experiment, is species-specific, and also gives the best fit to the empirical data. As the above-mentioned factors can strongly influence the value of the instantaneous rate of infection in the laboratory experiments, α0 is more suitable as a measure of either the larval infectivity for the snail or snail susceptibility to infection by the protostrongylid larvae.

Impacts of building envelope design factors upon energy loads and their optimization in US standard climate zones using experimental design

2017 ◽  
Vol 141 ◽  
pp. 1-15 ◽  
Author(s):  
Seok-Gil Yong ◽  
Jong-Hyun Kim ◽  
Yuseong Gim ◽  
Jinho Kim ◽  
Jinkyun Cho ◽  
...  
Keyword(s):  
Experimental Design ◽  
Building Envelope ◽  
Climate Zones ◽  
Design Factors

Explaining variability in parasite aggregation levels among host samples

Parasitology ◽  
2013 ◽  
Vol 140 (4) ◽  
pp. 541-546 ◽  
Author(s):  
ROBERT POULIN
Keyword(s):  
Body Size ◽  
Strong Relationship ◽  
Host Susceptibility ◽  
Helminth Parasites ◽  
Susceptibility To Infection ◽  
Host Body ◽  
Parasite Aggregation ◽  
Using Data ◽  
Species Specific ◽  
Host Body Size

SUMMARYAggregated distributions among individual hosts are a defining feature of metazoan parasite populations. Heterogeneity among host individuals in exposure to parasites or in susceptibility to infection is thought to be the main factor generating aggregation, with properties of parasites themselves explaining some of the variability in aggregation levels observed among species. Here, using data from 410 samples of helminth parasites on fish hosts, I tested the contribution of (i) within-sample variation in host body size, taken as a proxy for variability in host susceptibility, and (ii) parasite taxon and developmental stage, to the aggregated distribution of parasites. Log-transformed variance in numbers of parasites per host was regressed against log mean number across all samples; the strong relationship (r2 = 0·88) indicated that aggregation levels are tightly constrained by mean infection levels, and that only a small proportion of the observed variability in parasite aggregation levels remains to be accounted for by other factors. Using the residuals of this regression as measures of ‘unexplained’ aggregation, a mixed effects model revealed no significant effect of within-sample variation in host body size or of parasite taxon or stage (i.e. juvenile versus adult) on parasite aggregation level within a sample. However, much of the remaining variability in parasite aggregation levels among samples was accounted for by the number of individual hosts examined per sample, and species-specific and study-specific effects reflecting idiosyncrasies of particular systems. This suggests that with most differences in aggregation among samples already explained, there may be little point in seeking universal causes for the remaining variation.

Number of Shoes Tested During a Running Shoe Mass Perception Task May Not Influence Accuracy

2020 ◽  
Vol 127 (1-4) ◽  
pp. 23-29
Author(s):  
James G. Saxton ◽  
Joel G. Greenya ◽  
Christopher L. Kliethermes ◽  
David S. Senchina
Keyword(s):  
Young Adult ◽  
Experimental Design ◽  
Rank Order ◽  
Mass Accuracy ◽  
Testing Session ◽  
Adult Males ◽  
Order Task ◽  
Running Shoes ◽  
Design Factors ◽  
Analogue Scales

Commercially available running shoes differ in terms of their relative masses. It is unclear how well consumers may be able to judge mass differences from wearing alone, though previous studies suggest that perceptual outcomes may be influenced by experimental design factors such as the length of time worn. The purpose of this study was to investigate how the number of shoes used in a testing session impacts wearers' mass perceptual accuracy. Forty-eight young adult males ran for 5 min in 4 pairs of shoes (their own running shoes plus 3 unfamiliar pairs) before being asked whether an unfamiliar running shoe was heavier or lighter than their own, and to indicate perceptions of shoe heaviness (mass), comfort, stability, and temperature using visual analogue scales (VAS). A subset (n=18) was also asked to provide global rank orderings after wearing all 4 pairs of shoes. Participants were 67% accurate in the heavier/lighter task and 64% accurate in the global rank order task. Global rank order scores and VAS heaviness marks were significantly and positively correlated. Mass accuracy scores (n=48) were then compared to a previous study (n=25) performed by the same investigators using the same methods but with 6 pairs of shoes instead of 4. No difference in accuracy scores for either the heavier/lighter comparisons or global rank order scores between the study populations was found, suggesting that the number of test shoes may not influence mass perception accuracy.

scholarly journals Biomass Equations for 24 Understory Species in Coniferous and Broadleaved Mixed Forests in Northeastern China

2016 ◽  
Author(s):  
Huaijiang He ◽  
Chunyu Zhang ◽  
Fengguo Du ◽  
Xiuhai Zhao ◽  
Song Yang ◽  
...  
Keyword(s):  
Forest Ecosystem ◽  
Northeastern China ◽  
Individual Species ◽  
Total Biomass ◽  
Basal Diameter ◽  
Understory Species ◽  
Crown Area ◽  
Understory Plants ◽  
Species Specific ◽  
Best Fit

Understory plants are important components of forest ecosystem productivity and diversity. Compared to biomass models of overstory canopy trees, few are available for understory saplings and shrubs and therefore their roles in estimation of forest carbon pools are often ignored. In this study, we harvested 24 understory species including 4 saplings, 9 tree-like shrubs and 11 typical shrubs in coniferous and broadleaved mixed forest in northeastern China and developed the best fit allometric equations of above- and below-ground and total biomass by species-specific or multispecies using morphological measurements of basal diameter, height and crown area as independent variables. The result showed that single basal diameter, height or crown area had good explanatory power for both species-specific and multispecies (p<0.001). The best-fit models included only basal diameter in sapling and tree-like shrubs, and combinations of crown area, height, and basal diameter in typical shrubs. The logarithmic model was most desired among the 4 model forms of linear, quadratic, multiple linear and logarithmic, for species-specific and multispecies. The models we developed should help the estimation of forest ecosystem carbon stocks, especially for belowground component, and provide tools for quantification of individual species biomass of understory plants.

EFFECTS OF ENVIRONMENTAL AND EXPERIMENTAL DESIGN FACTORS ON CULTURING AND TOXICITY TESTING OF CERIODAPHNIA DUBIA

1992 ◽  
Vol 11 (6) ◽  
pp. 839 ◽  
Author(s):  
J.D. Cooney ◽  
G.M. DeGraeve ◽  
E.L. Moore ◽  
B.J. Lenoble ◽  
T.L. Pollock ◽  
...  
Keyword(s):  
Experimental Design ◽  
Toxicity Testing ◽  
Ceriodaphnia Dubia ◽  
Design Factors

scholarly journals Disruption of Human TRIM5α Antiviral Activity by Nonhuman Primate Orthologues

2005 ◽  
Vol 79 (12) ◽  
pp. 7883-7888 ◽  
Author(s):  
Lionel Berthoux ◽  
Sarah Sebastian ◽  
David M. Sayah ◽  
Jeremy Luban
Keyword(s):  
Leukemia Virus ◽  
Coiled Coil ◽  
Cyclophilin A ◽  
Susceptibility To Infection ◽  
Coiled Coil Domain ◽  
Immunodeficiency Virus ◽  
Species Specific ◽  
Hiv 1 ◽  
Modest Effect

ABSTRACT TRIM5 is a determinant of species-specific differences in susceptibility to infection by retroviruses bearing particular capsids. Human immunodeficiency virus type 1 (HIV-1) infection is blocked by the alpha isoform of macaque TRIM5 (TRIM5αrh) or by the product of the owl monkey TRIM5-cyclophilin A gene fusion (TRIMCyp). Human TRIM5α potently restricts specific strains of murine leukemia virus (N-MLV) but has only a modest effect on HIV-1. The amino termini of TRIM5 orthologues are highly conserved and possess a coiled-coil domain that promotes homomultimerization. Here we show that heterologous expression of TRIM5αrh or TRIMCyp in human cells interferes with the anti-N-MLV activity of endogenous human TRIM5α (TRIM5αhu). Deletion of the cyclophilin domain from TRIMCyp has no effect on heteromultimerization or colocalization with TRIM5αhu but prevents interference with anti-N-MLV activity. These data demonstrate that TRIM5 orthologues form heteromultimers and indicate that C-terminal extensions alter virus recognition by multimers of these proteins.

scholarly journals Morphological and Biological Characteristics of Amidostomum Anseris (Nematoda, Amidostomatidae) from Anser anser domesticus

2019 ◽  
Vol 53 (1) ◽  
pp. 65-74 ◽  
Author(s):  
V. А. Yevstafieva ◽  
V. V. Stybel ◽  
V. V. Melnychuk ◽  
О. В. Prijma ◽  
I. V. Yatsenko ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Infective Larva ◽  
Morphological Characteristics ◽  
Anser Anser ◽  
Size Dimorphism ◽  
Infective Larvae ◽  
Laboratory Conditions ◽  
Differential Characters ◽  
Species Specific ◽  
Amidostomum Anseris

Abstract Morphological characteristics were studied in adult and embryonic Amidostomum anseris (Zeder, 1800) obtained from domestic goose Anser anser domesticus Linnaeus, 1758. The studied characters included species-specific morphometric indices of male and female specimens and differential characters of sex-related dimorphism in that species. Stages and periods of embryonic development, and viability of the nematodes were studied at laboratory conditions. Size dimorphism in A. anseris was considerable, females were significantly larger (by 10.09–27.98 %) than males by 11 parameters. Additional metric characters were proposed to enhance effectiveness of differentiation of female and male A. anseris specimens. Under laboratory conditions, embryonic development of A. anseris occurs in four stages: blastomere cleavage; larval formation; formation of non-infective larvae I and II; formation of infective larva III which hatches from the egg. Infective larvae develop at 23 °С in six days, and their viability was up to 78.33 ± 2.08 %.

Do Usability Design Features of a Mobile Game Influence Learning?

2018 ◽  
pp. 2466-2476
Author(s):  
Rex Perez Bringula ◽  
Edison Cabrera ◽  
Princess B. Calmerin ◽  
Eduardo A. Lao ◽  
Christian Gerard Sembrano ◽  
...  
Keyword(s):  
Experimental Design ◽  
Disaster Response ◽  
Null Hypothesis ◽  
Response Learning ◽  
Learning Gains ◽  
Design Features ◽  
Design Factor ◽  
Mobile Game ◽  
Test Items ◽  
Design Factors

This one-group pretest-posttest experimental design study presented the effects of mobile game on students' disaster response learning. It also determined which of the usability features of the game might influence learning of students. Ninety-eight students utilized the game for three consecutive days (i.e., the intervention period). It was shown students learn significantly in terms of responding to fire, flood, tsunami, and volcanic eruption but not on storm and earthquake situations. The game did not contribute significantly to the knowledge of the students on storms since students are already attuned to storms. Students did not achieve a significant learning gains in earthquake test items because earthquake drills were conducted in local, institutional, and national levels before the study was initiated. Aesthetics was the only usability design factor that can influence learning. Thus, the null hypothesis stating that the usability design factors do not influence students learning was partially rejected. Recommendations were also offered.

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