scholarly journals Relevance of reproductive correlates in response of diamondback moth (Lepidoptera: Plutellidae) to plant quality

2013 ◽  
Vol 45 (2) ◽  
pp. 10 ◽  
Author(s):  
M. Soufbaf ◽  
Y. Fathipour ◽  
M.P. Zalucki ◽  
J. Karimzadeh
Keyword(s):  
Diamondback Moth ◽  
Reproductive Potential ◽  
Fertility Rate ◽  
Regression Coefficients ◽  
Initial Population ◽  
Reproductive Parameters ◽  
Plant Nitrogen ◽  
Fecundity Rate ◽  
Standardized Regression Coefficients ◽  
The Difference

To study the relationships between leaf nitrogen and the reproductive potential of diamondback moth, all reproductive parameters of this pest raised on two canola cultivars were evaluated. A standardized regression coefficient (<em>&beta;</em>) was used as an index for nitrogen-reproduction relationship strength. The only difference between net fecundity rate and net fertility rate is <em>h<sub>x</sub></em>&rsquo;s effect, but the difference in their standardized regression coefficients was not significant [<em>&beta;</em>=+0.934 (R<sup>2</sup>=0.87, F<sub>1,4</sub>=27.34, P=0.006) and <em>&beta;</em>=+0.922 (R<sup>2</sup>=0.85, F<sub>1,4</sub>=22.825, P=0.009)]. Accordingly, gross fecundity rate and gross fertility rate differ only in <em>h<sub>x</sub></em>&rsquo;s effect, but the difference in standardized regression coefficients again was not significant [<em>&beta;</em>=0.895 (R<sup>2</sup>=0.8, F<sub>1,4</sub>=16.159, P=0.016)-0.890 (R<sup>2</sup>=0.79, F<sub>1,4</sub>=15.266, P=0.017)=0.005]. As gross fecundity rate differs from net fecundity rate only in midpoint survivorship (<em>L<sub>x</sub></em>)&rsquo;s effect, it is understood that survivorship could affect the plant nitrogen&ndash;fecundity relation considerably (standardized coefficients difference=0.044) and could be a critical parameter in insectplant interactions. But, the terms of reproductive parameters, <em>i.e. L<sub>x</sub> </em>and <em>h<sub>x</sub></em>, showed the same effect on the strength of nitrogen-fecundity regression statistically, even though <em>L<sub>x</sub></em> has been selected frequently by many researchers as an important fitness correlate. Measuring the hatch rate could be recommended in trophic interactions studies due to its being easier to apply, more robust, and quicker to accomplish than measurement of survivorship; however, it is important as an indicator in combination with brood size for determining the initial population size of an insect herbivore.

Difficulties Detecting Fraud? The Use of Benford’s Law on Regression Tables

2011 ◽  
Vol 231 (5-6) ◽  
Author(s):  
Johannes Bauer ◽  
Jochen Groß
Keyword(s):  
Research Area ◽  
Regression Coefficients ◽  
Benford’S Law ◽  
Investigation Method ◽  
Scientific Fraud ◽  
Standardized Regression Coefficients ◽  
Significant Difference ◽  
Benford's Law ◽  
The Difference

SummaryThe occurrence of scientific fraud damages the credibility of science. An instrument to discover deceit was proposed with Benford’s law, a distribution which describes the probability of significant digits in many empirical observations. If Benford-distributed digits are expected and empirical observations deviate from this law, the difference yields evidence for fraud.This article analyses the practicability and capability of the digit distribution to investigate scientific counterfeit. In our context, capability means that little data is required to discover forgery. Furthermore, we present a Benford-based method which is more effective in detecting deceit and can also be extended to several other fields of digit analysis. We also restrict this article to the research area of non-standardized regressions. The results reproduce and extend the finding that non-standardized regression coefficients follow Benford’s law. Moreover, the data show that investigating regressions from different subjects demands more observations and hence is less effective than investigating regressions from single persons. Consequently, the digit distribution can discover indications for fraud, but only if the percentage of forgery in the data is large. With a decreasing proportion of fabricated values, the number of required cases to detect a significant difference between real and fraudulent regressions rises. Under the condition that only few scientists forge results, the investigation method becomes ineffective and inapplicable.

scholarly journals Agglomeration economies, congestion diseconomies, and fertility dynamics in a two-region economy

2021 ◽  
Author(s):  
Madoka Muroishi ◽  
Akira Yakita
Keyword(s):  
Population Size ◽  
Stability Condition ◽  
Fertility Rate ◽  
Model Parameters ◽  
Initial Population ◽  
Interregional Migration ◽  
Stable Path ◽  
Regional Population ◽  
Initial Population Size

AbstractUsing a small, open, two-region economy model populated by two-period-lived overlapping generations, we analyze long-term agglomeration economy and congestion diseconomy effects of young worker concentration on migration and the overall fertility rate. When the migration-stability condition is satisfied, the distribution of young workers between regions is obtainable in each period for a predetermined population size. Results show that migration stability does not guarantee dynamic stability of the economy. The stationary population size stability depends on the model parameters and the initial population size. On a stable trajectory converging to the stationary equilibrium, the overall fertility rate might change non-monotonically with the population size of the economy because of interregional migration. In each period, interregional migration mitigates regional population changes caused by fertility differences on the stable path. Results show that the inter-regional migration-stability condition does not guarantee stability of the population dynamics of the economy.

scholarly journals Concealed correlations meta-analysis: A new method for synthesizing standardized regression coefficients

2018 ◽  
Vol 51 (1) ◽  
pp. 316-331 ◽  
Author(s):  
Belén Fernández-Castilla ◽  
Ariel M. Aloe ◽  
Lies Declercq ◽  
Laleh Jamshidi ◽  
Patrick Onghena ◽  
...  
Keyword(s):  
Meta Analysis ◽  
New Method ◽  
Regression Coefficients ◽  
Standardized Regression Coefficients

THE FALLACY OF EMPLOYING STANDARDIZED REGRESSION COEFFICIENTS AND CORRELATIONS AS MEASURES OF EFFECT

1986 ◽  
Vol 123 (2) ◽  
pp. 203-208 ◽  
Author(s):  
SANDER GREENLAND ◽  
JAMES J. SCHLESSELMAN ◽  
MICHAEL H. CRIQUI
Keyword(s):  
Regression Coefficients ◽  
Standardized Regression Coefficients

EFFECTS OF PARASITISM BY TOMICOBIA TIBIALIS ASHMEAD (HYMENOPTERA: PTEROMALIDAE) ON REPRODUCTIVE PARAMETERS OF FEMALE PINE ENGRAVERS, IPS PINI (SAY)

1992 ◽  
Vol 124 (3) ◽  
pp. 509-513 ◽  
Author(s):  
Susan E. Senger ◽  
Bernard D. Roitberg
Keyword(s):  
Power Analysis ◽  
Statistical Power ◽  
Biocontrol Agent ◽  
Reproductive Potential ◽  
Ips Pini ◽  
Larval Survival ◽  
Reproductive Parameters ◽  
Tomicobia Tibialis ◽  
Healthy Females ◽  
Healthy Males

AbstractThe effects of Tomicobia tibialis Ashmead on the reproductive potential of adult Ips pini (Say) females were examined by comparing reproductive indices of parasitized and healthy females maintained in groups of three with healthy males. Parasitized females produced 50% fewer offspring than healthy females, and these offspring were distributed differently in the maternal gallery. Maternal gallery length and larval survival were not significantly different between the two groups, but a statistical power analysis (1 − β) shows this result to be equivocal. The potential to use T. tibialis as a biocontrol agent against I. pini is discussed.

scholarly journals Reproductive potential of Spodoptera eridania (Stoll) (Lepidoptera: Noctuidae) in the laboratory: effect of multiple couples and the size

2016 ◽  
Vol 76 (2) ◽  
pp. 526-530 ◽  
Author(s):  
A. Specht ◽  
D. G. Montezano ◽  
D. R. Sosa-Gómez ◽  
S. V. Paula-Moraes ◽  
V. F. Roque-Specht ◽  
...  
Keyword(s):  
Reproductive Potential ◽  
Reproductive Parameters ◽  
Spodoptera Eridania ◽  
Adult Females ◽  
Controlled Conditions ◽  
Pupal Size ◽  
Lepidoptera Noctuidae

Abstract This study aimed to evaluate the effect of keeping three couples in the same cage, and the size of adults emerged from small, medium-sized and large pupae (278.67 mg; 333.20 mg and 381.58 mg, respectively), on the reproductive potential of S. eridania (Stoll, 1782) adults, under controlled conditions (25 ± 1 °C, 70% RH and 14 hour photophase). We evaluated the survival, number of copulations, fecundity and fertility of the adult females. The survival of females from these different pupal sizes did not differ statistically, but the survival of males from large pupae was statistically shorter than from small pupae. Fecundity differed significantly and correlated positively with size. The number of effective copulations (espematophores) and fertility did not vary significantly with pupal size. Our results emphasize the importance of indicating the number of copulations and the size of the insects when reproductive parameters are compared.

scholarly journals Egg production of Baltic cod (Gadus morhua) in relation to variable sex ratio, maturity, and fecundity

2002 ◽  
Vol 59 (12) ◽  
pp. 1908-1920 ◽  
Author(s):  
Gerd Kraus ◽  
Jonna Tomkiewicz ◽  
Friedrich W Köster
Keyword(s):  
Sex Ratio ◽  
Egg Production ◽  
Gadus Morhua ◽  
Reproductive Potential ◽  
Relative Fecundity ◽  
Spawning Stock ◽  
Class Strength ◽  
The Difference ◽  
Eastern Baltic ◽  
Baltic Cod

Observed fluctuations in relative fecundity of Eastern Baltic cod (Gadus morhua L.) were related to food availability during the main feeding period and were used to develop a predictive model that explained 72% of the interannual variations in fecundity. Time series of sex ratios, maturity ogives, and relative fecundity were combined with mean weights-at-age and stock sizes from an analytical multispecies model to estimate the potential egg production (PEP). Relationships between PEP and independent estimates of realized daily and seasonal egg production from egg surveys were highly significant. The difference between estimates of potential and realized seasonal egg production was of a magnitude corresponding to the expected loss of eggs as a result of atresia, fertilization failure, and early egg mortality. The removal of interannual variability in sex ratio, maturity, and fecundity on estimates of PEP deteriorated the relationships in all three cases. PEP proved to be superior to spawning stock biomass as measure of the reproductive potential in a stock-recruitment relationship of Eastern Baltic cod. PEP in combination with the reproductive volume explained 61% of the variation in year-class strength at age 2.

Determination of Retinol, Antioxidant Vitamins and Homocysteine in Skin Puncture Blood

1999 ◽  
Vol 69 (5) ◽  
pp. 309-314 ◽  
Author(s):  
Erhardt ◽  
Heinrich ◽  
Biesalski
Keyword(s):  
Mass Screening ◽  
Beta Carotene ◽  
Regression Coefficients ◽  
Precolumn Derivatization ◽  
Sampling Techniques ◽  
Blood Samples ◽  
Vitamin Status ◽  
The Difference ◽  
Better Than

For determination of the vitamin status via mass screening, simple and rapid methods are required. Additionally, blood samples should be obtained using simple and low invasive sampling techniques. To fulfill this existing methods have been modified to analyze retinol, tocopherols, beta-carotene, vitamin C and homocysteine in 20 mul plasma. Blood samples were obtained via skin punctures. HPLC measurements were carried out with isocratic separation and precolumn derivatization. Intra and interday variation coefficients were below 8% and regression coefficients better than 0.99 for all measurements. The difference between venous and capillary samples were < 5%. In conclusion, the methods employed proved satisfactory for the determination of important nutritional parameters in blood samples obtained via skin punctures. These methods are therefore well suited for mass screening, especially under field conditions in developing countries.

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