Production characteristics of settlements bivalve Mya arenaria Linne, 1758 of the Barents Sea

The linear growth equations and production for bivalve Mya arenaria (Linne, 1758) in the intertidal zone Yarnyshnaya and Zelenetskaya bays of Barents Sea are represented. Our studies have shown that length of the shell Mya reached 26.3–62.5 mm, the highest age was 11 years. Indicators of the growth rate of mollusks from Zelenetskaya Bay are significantly higher than those of mollusks from Yarnyshnaya Bay. Linear growth is described by the Bertalanfi equations: Lt = 84.27 [1–e–0.0721 (t–0.1244)] – for mollusks from Yarnyshnaya Bay, Lt = 118.49 [1–e–0.0566 (t–0.2744)] – for mollusks from Zelenetskaya Bay. Production in the intertidal zone of the Yarnyshnaya Bay was lower (44.8 g/m2 with a biomass of 330 g/m2) than in the intertidal zone of the Zelenetskaya Bay (90.5 g/m2, with a biomass of 258 g/m2). The P/V-value is the coefficient of 0.14 and 0.35, respectively.

How Our Cells Become Our Selves: The Cellular Phylodynamic Biology of Growth and Development

Our lives begin with 1 cell, then 2, then 4, then the trillion cell adult, comprised of cell lineages, tissues, organs. How does this occur? Examination in numbers of cells, N, Cellular Phylodynamics, revealed two previously unappreciated processes: UNI-GROWTH, the slowing of growth that occurs as we become larger, caused by fewer cells dividing, captured by the Universal Mitotic Fraction and Universal Growth Equations, with accuracy confirmed for 13 species, including nematodes, mollusks, and vertebrates; and ALLO-GROWTH, the creation of body parts from Founder Cells, captured by the Cellular Allometric Growth Equation, which describes mitotic expansion by Cell-Heritable change in the Cell Cycle Time. These equations can generate cell lineage approximations, bringing the power of coalescent theory to developmental biology.

Role OF Structural Indices and Other Spatial Measures in the Improvement Of Crown Variables Prediction For Lannea fructicosa

Theoretically, the stem of the tree must be strong enough to withstand the forces that act on it. These forces include the weight of the crown and the drag exerted on it by the wind. This mean that for a well-established root system, there should be some kind of balance between crown and stem sizes, otherwise the stem be break. The sizes, shapes and relative locations of crowns both determine and respond to the shading and constriction effects that characterize aboveground interactions between trees. Due to this kind of balance, tree crown parameters have been used as predictor variables in diameter and height growth equations. Although the correlation between tree variables and crown dimensions has well documented in the literature, other stand composition and conditions such as competition, elevation and aspect are believed to be among the unexplained forces that exert strong influences on the accuracy of the allometric models used for that relationship. This study attempted to quantify the effect of structural indices and other spatial measures to improve the prediction of crown radius and crown length for trees in natural woodlands. Field data were recorded for Lannea fruticosa tree species that naturally grown in Elgarri forest reserve in Blue Nile State, Sudan. The data was used to test the performance of estimating crown dimensions on the basis of allometric relationships with tree diameter and height. A total of thirteen spatial and non-spatial indices were incorporated into modified crown dimension models. Coefficient of multiple determination (R2) and relative bias were used to test the performance of these indices in improving the accuracy of estimates. According to the results all predictions of crown length and radius were found to be better after the incorporation of the spatial and non-spatial, with positive R2 gain and acceptable negative bias values for crown radius and positive ones for crown length. For all cases, the spatial indices were found to be better than the non-spatial ones.

Parameters of equations for group growth of golden king crab Lithodes aequispinus in the northern Okhotsk Sea

Growth of golden king crab in the northern Okhotsk Sea is considered. Parameters of von Bertalanffy growth equation were estimated using SLCA method (Shepherd's length composition analysis): the asymptotic carapace width W∞ was 252.0 mm for males and 165.3 mm for females; the growth rate K was 0.081 and 0.130, respectively. Relative increment per molt for males with carapace width of 116-154 mm was estimated as 11.6 % for the carapace width and 10.9 % for the carapace length. Directly determined (by tagging) dependence of males molt frequency on their size was approximated by logistic curve of molting probability with the threshold of 164 mm carapace width for 50 % probability of annual molt. Mean probability of annual molt for recruits was estimated as 87 %, for pre-recruits — as 92 %. Taking into account the data on increment per molt and annual molt probability, the growth curve for males had the parameters: W∞ = 296 mm and K = 0.073. The age of recruits was estimated as 9 years by SLCA approach and as 8 years on the results of tagging. The growth equations parameters were determined for the first time for golden king crab in natural habitat in the Russian waters. These results could be used in models and for theoretical studies of Crustacean life history.

Age, Growth, and Natural Mortality of Whitebone Porgy, Calamus Leucosteus, From the Southeastern United States

Ages of whitebone porgy (Calamus leucosteus) (n = 559) from southeastern U. S. commercial and recreational fisheries from 1975 – 2017 were determined using sectioned otoliths. Opaque zones were annular, forming April – July (peaking in June). Ages ranged from 2 – 19 years, and the largest fish measured 513 mm TL (total length, mm). Body size relationships were: TL = 1.09 FL + 16.07 (n = 469, r2 = 0.97), FL = 0.89 TL – 6.39 (n= 469, r2 = 0.97), W = 2.8 x 10-5 TL2.91 (n = 462), and W = 6.8 x 10-5 FL2.82 (n = 417) where W is total weight (grams, g) and FL is fork length (mm). The von Bertalanffy growth equations were Lt = 365 (1 - e-0.35 (t + 1.37)) (n = 559) for all areas combined, Lt = 365 (1 - e-0.55(t + 0.00)) (n = 185) for fish from North Carolina through Cape Canaveral, Florida, and Lt = 368 (1 - e-0.25 (t + 2.51)) (n = 374) for fish from southeast Florida. Mean size-at-age was significantly different between regions for ages 4 – 9, (92% of total samples). Point estimates of natural mortality were M = 0.22 and M = 0.30 for northern- and southern-region fish, respectively, while age-specific estimates of M were 0.85 – 0.55 y-1 for ages 2– 19 for the northern region and 0.41 – 0.26 (ages 2-14) for southern region fish. This study presents updated life history parameters for whitebone porgy from the Atlantic waters off the southeastern United States.

Educational Expansion and Economic Growth Nexus in Pakistan: Instrumental Variable Approach

This study examines the relationship between economic growth and the expansion of education in Pakistan. The study utilizes 2SLS and GMM estimators to estimate the growth equations with a potential issue of endogeneity using data for the period 1973-2018. Empirical results show that educational expansion at the primary and secondary level effect economic growth positively. The evidence is quite compelling that the effect of educational expansion on economic growth is low due to the poor quality of education. Also, the lower effect of physical capital is due to lower human capital embodied in the labor force. Keywords: human capital; economic growth; GMM; Endogeneity; Pakistan. JEL Classification: O47, I21, C26

Developing Growth Models of Stand Volume for Subtropical Forests in Karst Areas: A Case Study in the Guizhou Plateau

Forest stand volume is one of the key forest structural attributes in estimating and forecasting ecosystem productivity and carbon stock. However, studies on growth modeling and environmental influences on stand volume are still rare to date, especially in subtropical forests in karst areas, which are characterized by a complex species composition and are important in the global carbon budget. In this paper, we developed growth models of stand volume for all the dominant tree species (groups) (DTSG) in a subtropical karst area, the Guizhou Plateau based on an investigation of the effects of various environmental factors on stand volume. The Richards growth function, space-for-time substitution and zonal-hierarchical modeling method were applied in the model fitting, and multiple indices were used in the model evaluation. The results showed that the climatic factors of annual temperature and precipitation, as well as the site factors of stand origin, elevation, slope gradient, topsoil thickness, site quality degree, rocky desertification type and rocky desertification degree, have significant influences on stand volume, and the topsoil thickness and site quality degree have the strongest positive effect. A total of 959 growth equations of stand volume were fitted with a five-level stand classifier (DTSG–climatic zone–site quality degree–stand origin–rocky desertification type). All the growth equations were qualified, because all passed the TRE test (≤30%), and the majority of the R2 ≥ 0.50, above 70% of the RMSE were between 5.0 and 20.0, and above 80% of the P ≥ 75%. These findings provide updated knowledge about the environmental effect on the stand volume growth of subtropical forests in karst areas, and the developed stand volume growth models are convenient for forest management and planning, further contributing to the study of forest carbon storage assessments and global carbon cycling.

Study of the growth of three species: Micropterus salmoides (Lacépède, 1802), Cyprinus carpio (Linneaus, 1758) and Oreochromis niloticus (Linnaeus, 1758) in Moroccan continental waters

The growth parameters of three species were studied for the first time in the AlMassira Dam. A total of 137 individuals were examined during this study between September 2020 and January 2021. The estimation of growth parameters was carried out by size structure analysis using FISAT II software. The growth parameters of Micropterus salmoides, Cyprinus carpio and Oreochromis niloticus are respectively: L∞= 35.11 cm, K= 0.58 year-1, t0= 0.57 year; L∞= 44.85 cm, K= 2.60 year-1, t0= 1.27 year and L∞= 45.26 cm, K= 0.32 year-1, t0= 0.33 year. Thus, the Von Bertalanffy growth equations are written respectively: L(t) = 35.11 (1-e-0.58 (t+0.57)), L (t)= 44.85 (1-e-2.60 (t+1.27)) and L (t)= 45.26 (1-e-0.32 (t+0.33)).