Allometry Coefficients Research Articles

Length-weight relationship and condition factor of Micralestes eburneensis populations from the Cavally River in Côte d’Ivoire

This study aims to show the effect of anthropogenic pressures on populations of Micralestes eburneensis caught in the River Cavally in Côte d’Ivoire. Sampling took place from April 2015 to May 2017. The fish caught came from experimental and artisanal fisheries. The length-weight relationship and condition factor were determined using the equations P = aLSb and K = 100*P/LS, respectively. A total of 349 individuals with a standard length of between 48 mm and 82 mm and a mass ranging from 3 g to 10 g were caught. The coefficient of determination (r2) values recorded ranged from 0.66 to 0.88. The estimated allometry coefficients for M. eburneensis were 2.81, 2.55 and 2.42 upstream, in the mining zone and downstream respectively. The condition factors of M. eburneensis individuals sampled in the Cavally river fluctuated between 0.66 and 1.39 with a median value of 1.05. The lowest values (K = 0.66 - 0.88) were recorded during the dry season. The size range in the three best-represented sampling areas is between 66 and 74 mm (standard length). This study contributes to our knowledge of the biology of M. eburneensis and provides a specific database on the length-weight relationship and condition factor of the species M. eburneensis from the Cavally River.

Mullus barbatus L. and Mullus surmuletus L. from western Mediterranean waters (SE Spain) are infected by Hysterothylacium fabri, but not by zoonotic nematodes. Possible impact on fish hosts.

In order to know whether there is a risk of anisakiasis (or anisakidosis) by consumption of fish of the genus Mullus from the western Mediterranean Sea, which are appreciated for their quality, an epidemiological survey was carried out to evaluate the occurrence of zoonotic or potentially zoonotic nematodes in M. barbatus and M. surmuletus. Although the presence of the third larval stage (L3) of anisakids (Anisakis and Contracaecum) has been previously described in these fish, the results showed the absence of anisakids and the presence, never in muscle, of L3 and L4 of raphidascaridids of the genus Hysterothylacium, molecularly identified as H. fabri. Phylogenetic analysis groups them into the Mediterranean Sea clade, far from individuals isolated in the Pacific Ocean. Prevalence was slightly higher, but not significant, in M. barbatus versus M. surmuletus (72.3% vs 60.0%), but mean intensity (MI) and mean abundance (MA) parameters were approximately twice as high in M. barbatus as in M. surmuletus (MI 5.8 vs 2.8, p = .001; MA 4.2 vs 1.7, p < .001). The presence of the parasite seems to have different effects on these two sympatric species. In M. barbatus it seems to affect their growth, as it appreciably reduces the value of allometry coefficient in infected fish (2.78 vs. 2.18). On the other hand, in M. surmuletus the infection significantly (p < .04) affects the Fulton's condition factor, an indicator of the health status of the fish. It can be concluded that the ingestion of these fish by the people poses negligible risk of anisakiasis, but the consumer should continue to be urged to follow the rules of prevention against this illness.

Morphometric study of sex differences and static variation in the skull of Indochinese ground squirrel, Menetes berdmorei (Rodentia: Sciuridae)

Sexual dimorphism, a common morphological phenomenon in rodents, has often been explained as the result of both sexual and natural selection. However, few studies have focused on detailed patterns of sexual dimorphism in squirrels. In this study, we investigated the patterns of sex differences and static variation in the skull of Indochinese ground squirrel (Menetes berdmorei) using linear morphometrics. A total of 24 adult skulls (15 males and 9 females) were measured, of which males showed slightly larger mean size in 19 measurements. Univariate analyses demonstrated significant differences between the sexes in few variables, while discriminant analysis indicated well distinctiveness in craniomandibular morphology. The coefficient of variation showed an inverse relationship with the mean values of skull traits. This trend might be caused by real biological phenomena, as previously reported in several studies. Although coefficient of variation tended to be larger in anterior part of the viscerocranium and smaller in posterior of the neurocranium, similar variability patterns were observed in most of the skull trails. These trends were also supported by the alternative index of the coefficient of variation and coefficients of bivariate allometry. Even though, existence of developmental factors is suggested by the patterns of variability, higher integration is denoted in major subdivisions of the skull. In conclusion, our results demonstrate a slight male-biased sexual size dimorphism in M. berdmorei. Besides, variability patterns might indicate higher morphological integration in major components of the skull.

Weight-Length and Length-Length Relationships of the Endangered Zebra Pleco Hypancistrus zebra (Siluriformes, Loricariidae) from the Xingu River, Amazon, Brazil

Hypancistrus zebra is a Loricariid endemic to a very limited stretch of the Xingu River and has a high value in the ornamental fish trade. The natural populations have experienced high fishing pressure since the late 80s and were recently impacted by the construction of the third largest hydroelectric dam complex in the world, the Belo Monte Project. Since 2004, it has been considered critically endangered and had its capture and trade forbidden. Even with its capture and trade prohibited since 2004, the species continues to be one of the most trafficked fish in the world. The biometric knowledge of the species is essential for monitoring its natural populations and management in ex situ environments. This work aims to establish the weight-length relationship (WLR) and length-length relationship (LLR) of the species and to evaluate the condition factor (K) of H. zebra rescued from trafficking. The study was conducted at the Laboratório de Aquicultura de Peixes Ornamentais do Xingu from February 2022 to June 2022, estimating the parameters of WLR and LLR of 1165 specimens divided into four simple linear regression (SLR) models: all specimens, only juveniles, only females, and only males. The K of 190 specimens rescued from trafficking by the Brazilian Federal Police was evaluated. The WLRs and LLRs were estimated using SLR. The difference between the allometry coefficients (b) and between the residuals of the models (juveniles, females, and males) was evaluated using the ANOVA significance test. The total length of the species ranged from 1.6 to 9.3 cm. The coefficient of allometry (b) of the WLR of the species is 3.22 and of the LLR is 1.04, demonstrating that H. zebra presents positive allometric growth. The evaluation of the residuals of the models showed differences between ontogenetic stages and between sexes. The development of juveniles is isometric until the first sexual maturation phase and differs in negative allometric for females and positive allometric for males, showing sexual dimorphism in the species. Among the specimens rescued from trafficking, 54.74% were underweight, and 13.16% were under 60% of the expected K value, demonstrating the poor conditions in which these animals are transported by trafficking.

Estimation of differential growth of the protandrous hermaphrodite marine gastropod Trochita trochiformis (Littorinimorpha: Calyptraeidae) using Schnute model cases

The snail Trochita trochiformis is a mollusk captured on the coasts of Jalisco and Guerrero of the Mexican Pacific. Despite its importance in artisanal fisheries, information on its population parameters is still being determined. This research aimed to determine the diameter-weight relationship, sex ratio, cohorts, and growth of this species. Specimens were captured from October 2019 to September 2021. Shell diameter (Sd), total weight (Tw), and the sex of the organisms were gathered from a total of 1763 females and 956 males. The sex ratio was 1.84:1, and the X2 test (P &lt; 0.05) indicated significant differences. The Sd-Tw relationship for females and males was potential-type. The values of the allometry coefficient for both sexes were b = 2.61, b = 2.60 for females, and b = 2.62 for males. In all three cases, the t-Student test indicated negative allometric growth, which indicates that the species first grows in shell diameter, then in body weight. The ANCOVA did not show significant differences in the Sd-Tw relationships between sexes (P = 0.902). The Kolmogorov-Smirnov test applied to the Sd data showed differences between sexes (P &lt; 0.001). In females, differences were observed in 71.5% by monthly comparisons, while in males, differences were found in 58.1%. Multinomial analysis showed three modal groups and 14 individual cohorts for both females and males. Case 2 of the Schnute model was the best for females (wi = 0.39) and males (wi = 0.53), showing sigmoidal Gompertz-type growth. The resulting growth curves showed that females exhibit accelerated growth concerning males and that both sexes reach their maximum size, 88.04 and 86.23 mm, respectively, at approximately 10 years of age.

Biometric Characteristics and Condition Index of the Mangrove Oyster Crassostrea tulipa Lamarck, 1819 in the Interface Ecosystems of the Saloum Delta in Senegal: Case of the Commune of Dionewar

The mangrove oyster Crassostrea tulipa (syn. Crassostrea gasar) has been subjected to strong anthropic pressure. As in several West African countries, Senegal in particular in the Saloum delta, the oyster resource was severely strained. This situation had led to disturbances in the renewal of stocks and their productivity. The objective of this study was to determine the size frequency distribution, the size-weight relationship and the condition index in order to provide scientific arguments for sustainable management of C. tulipa. Monthly sampling from January 2021 to January 2022 at the Akat, Baobab Rasta, Falia 1, Falia 2 and Fandiongue stations revealed that the individual sizes of the oysters collected ranged from 0.63 mm to 93.19 mm, with an average height of 34.63 ± 16.12 mm. The size frequency distribution is unimodal with a modal class of 30 - 40 mm and the allometry coefficient is minorizing (2.57). The correlation coefficient is 0.86. However, from one site to another the differences are not significant. The monthly monitoring of the oyster condition index showed several variations in values throughout the year, with an overall average of 11.47±2.89% for the 5 stations. The maximum value (12.97±2.60) was observed in March while the minimum value (9.85±2.22) was recorded in November. This study suggests that C. tulipa is overexploited in the commune of Dionewar and that the best time to collect the oyster is around March.

CONDITION FACTOR AND LENGTH-MASS RELATIONSHIP OF THE MAIN FISH SPECIES IN THE BANDAMA RIVER DOWNSTREAM OF THE TAABO DAM (COTE DIVOIRE)

Length-mass relationship and condition factor are important tools used in biology, ecology and stock assessment for the management and conservation of fish populations and also to assess the level of disturbance of an aquatic ecosystem. The present study aims at providing baseline data on the length-mass relationship and condition factor of sixteen (16) fish species landed at NDènou, downstream of the Taabo dam, prior to the impoundment of the dam under construction on this part of the Bandama River. The fish were collected monthly from november 2019 to october 2020.They were measured (standard length in cm) and weighed (mass in g). The data were processed in Excel and Statistica 7.1 software. A total of 16047 fish were examined. The standard lengths of these fish varied from 3.50 to 40 cm with masses ranging from 2.87 to 1400 g. The values of the allometry coefficient ranged from 1.64 for Hemichromisbimaculatus to 2.99 for Labeocoubie. Fourteen (14) fish species studied have negative allometric growth (b &lt; 3 p &lt; 0.05). Distichodusrostratus and Labeocoubie species have isometric growth. The condition factor has values between 0.83 ± 0.39 (Mormyropsanguilloides) and 3.65 ± 0.74 (Coptodonhybrid).

Growth, exploitation parameters and sexual maturity of Chrysichthys nigrodigitatus (Lacépède, 1803) downstream of the Taabo dam (Bandama River, Côte d’Ivoire)

The objective of the present work is to study the growth, exploitation parameters and the size of first sexual maturity of Chrysichthys nigrodigitatus (Lacépède, 1803) landed in N'dènou, in order to evaluate the status of its stock. A total of 7635 fish were sampled monthly from November 2019 to October 2020. The individuals were measured, weighed and the data processed with the FiSAT II software. The calculated parameters are: allometry coefficient (b = 2.77); asymptotic length (L∞ = 51.98 cm); growth coefficient (K = 0.2 yr-1); growth performance index (φ' = 2.73); natural mortality (M = 0.54 yr-1); fishing mortality (F= 0.61 yr-1); total mortality (Z = 1.14 yr-1); exploitation rate (E = 0.53). The size of first capture is smaller than the size of first sexual maturity. Recruitment is continuous with the peak during the rainy season. The C. nigrodigitatus stock is under fishing pressure in the Bandama River.

Effects of selenium nanoparticle on the growth performance and nutritional quality in Nile Tilapia, Oreochromis niloticus.

Selenium is an important micronutrient that has antioxidant, growth potential, and reproduction enhancement abilities in various organisms. The aquaculture industry is a significant contributor towards meeting the dietary requirements of a majority of the global population, which further warrants developing novel approaches for enhancing the production of dietary fish. This study was performed to assess the growth performance of Nile tilapia (Oreochromis niloticus) fingerlings (1 gm in average weight and 2.75 cm in average length) upon nano-selenium (Se-Nps) supplementation. Nanoselenium was synthesized using high-energy ball milling (HEBM) using a 10-hour dry milling technique at 10:1 ball-to-powder ratio (BPR), size characterized by XRD and TEM, followed by mixing with basal feed in desired concentrations (0.5 mg/kg, 1 mg/kg, and 2 mg/kg) and administration to Nile tilapia fingerlings for 30 days, followed by the evaluation of growth performance parameters, fatty acid profile analysis using GC-MS, and nutritional quality index (NQI): [Thrombogenicity Index (IT), Atherogenicity Index (IA), n-3/n-6, n-6/n-3)]. Nile tilapia supplemented with 1 mg/kg Se-Nps showed improved growth performance (RGR: 1576.04%, SGR: 4.70%, and FCR: 1.91), demonstrated by higher survivability (> 95%), isometric growth (coefficient of allometry, b = 2.81), and higher weight gain compared to control (RGR: 680.41%, SGR: 3.42%, and FCR: 1.31), 0.5 mg/kg Se-Nps (RGR: 770.83%, SGR: 3.61%, and FCR: 1.18) and 2 mg/kg Se-Nps (RGR: 383.67%, SGR: 2.63%, and FCR: 1.22). The average length-weight relationship assessed as the condition factor (K) was highest in the 1 mg/kg Se-Nps group compared to others (p < 0.05). GC-MS analysis revealed that Nile tilapia supplemented with 1 mg/kg Se-Nps showed better meat quality, higher amount of n-3 fatty acids, eicosapentaenoic acid, and docosahexaenoic acid, high PUFA/SAFA ratios (1.35) and n-3/n-6 (0.33) ratios, with low atherogenicity index (0.36) and thrombogenic index (0.44), and relatively low n-6/n-3 fatty acid ratio (3.00) compared to other groups. Overall, Se-Nps supplementation at 1 mg/kg enhanced the growth performance and meat quality in Nile tilapia, and therefore could be a potential growth-promoting micronutrient for aquaculture enhancement.

Length Weight Relationships and Condition Factor of Sicydium sp. (Gobiidae) from the Yallahs River and Swift River, Jamaica

Sicydium sp., commonly known as gobies, are migratory freshwater fish that spend most of their life cycle in rivers, but when the larvae emerge they drift downstream to the sea where further development of juveniles occurs. Although Sicydium sp. are abundant in Jamaican rivers, little is known about the ecology of these species on the island and throughout the Caribbean. This study examines aspects of the ecology and biology of Sicydium populations in Jamaica. Fish sampling was carried out using dip nets and bottom kick nets at sites along the south coast in the Yallahs River, and along the north coast in the Swift River. A total of 850 gobies were captured, measured, and weighed. The values of the allometry coefficient or growth pattern (b) in the length weight relationships (LWR) were significantly different among males, females, and juveniles (p < 0.05). The growth pattern derived from LWR's was positive for females, males, and juveniles in the Yallahs River, and positive for females and juveniles but negative for males in the Swift River. The mean Fulton's condition factor (K) indicates that fish populations in both rivers are healthy and in good condition. These results augment the body of knowledge on Sicydium gobies in Jamaica.

Length-Weight Relationship And Condition Factor Of Mangrove Fish Species In Azagny National Park (Grand-Lahou Department, Ivory Coast)

The length-weight relationship and condition factor of mangrove fish species in Azagny National Park (ANP) were studied, to provide baseline data of the impact of mangrove disturbances on ichthyofauna. Specimens were captured from March 2019 to February 2020 using gillnets and mesh traps. After identification, each specimen was weighed to the nearest gram and measured to the nearest millimeter. Twenty-eight species belonging to 17 families and 24 genera were selected based on their numbers (only species with at least 10 specimens were considered). Most of these species have a negative allometry (22 species, 78.57%). 14.28% species showed positive allometry and 7.14% species showed isometry. The length-weight regressions are significant with a coefficient of determination (r²) varying between 0.115 for Chrysichthys maurus and 0.936 for Labeo coubie. The coefficient of allometry b varies from 0.413 for Chrysichthys maurus to 4.272 for Labeo coubie with a mean value of 2.384 ± 0.810. The condition factor ranged on average from 0.935 ± 0.966 for Schilbe mandibularis 113.3 ± 10.644 for Chrysichthys maurus. This study provides information on the effects of mangrove disturbance on the growth of species of the said ecosystem and contributes to the management of the ichthyofauna of the ANP.

Allometry of the box crab Calappa convexa De Saussure, 1853 (Brachyura, Calappidae) in the southeastern Gulf of California

Abstract The relative growth of Calappa convexa can be used to identify dimorphism or morphological change related to sexual maturation. The carapace width (CW) against width and length of the propodus of the right and left cheliped were tested to obtain a coefficient of allometry. CW against total wet weight WT values were analysed for length-weight relationships (LWR). Relative growth was analysed by a multi-model approach. Five models were tested and the best was selected due to the greater weight of the Akaike criterion (). Significant differences between sexes were found in CW (, ) and WT (, ). The negative or positive allometry varied according to the morphometric relationship and sex. No real winner model () was observed in the LWR analysis under a multi-model approach. The average model estimated a breakpoint at 118 mm CW in males and 132 mm CW in females.

Age, growth and mortality of the yellowmouth barracuda Sphyraena viridensis (Sphyraenidae) from eastern coasts of Algeria

AbstractAge and growth of the yellowmouth barracuda Sphyraena viridensis (Cuvier, 1829) was examined in 698 individuals (184 &lt; TL (mm) &lt; 1210; 25 &lt; TW (g) &lt; 7125), sampled monthly from commercial catches in eastern coasts of Algeria between January 2007 and January 2008. Marginal increment analysis of 159 sectioned sagittal otoliths combined with information derived from length–frequency distribution showed that annulus formation occurs between June and August. Maximum observed age of males and females is 14 and 13 years respectively. Back calculations of total length-at-age were used to fit the data to the Bertalanffy growth model: TL = 1113(1 – e−0.165(t+2.251)) in males and TL = 958.3 (1 – e−0.247(t+1.422)) in females. The coefficient of allometry of the length weight relationship is 3.02 and 2.99 in males and females, respectively. Growth performance index Ø = 3.33. Natural mortality (M) was estimated as 0.45 year−1, fishing mortality (F) was 0.06 year−1and the exploitation rate (E) was 0.11.

Growth Characteristics of Edible Land Crab &amp;lt;i&amp;gt;Cardisomaarmatum&amp;lt;/i&amp;gt; (Brachyura: Gecarcinidae) from KribiMangroves, Cameroon

The land crab <i>Cardisoma armatum</i> is traditionally overexploited for consumption issue in Cameroonian mangroves. However, the exploitation of this natural resource ignores sustainable management. Hence, the study aims to assess the availability and growth patterns of <i>C. armatum</i> in Kribi mangroves throughout some of their morphological parameters. Several individuals were captured inside traps baited once each two months from March 2019 to March 2020. Then, wellbeing, growth patterns and size at the first sexual maturity were assessed based on sex, seasons or maturity stages. Despite the fact that the condition factor (K) value overall remained below 1, females and matures individuals were in a better wellbeing compared to males and immature. In the CW-BW relationships, the allometry coefficients (b) were below 3 for both sexes, suggesting a negative allometry growth patterns which means that crabs are lighter than their body weights. In the CW-CL and CW-BH relationships, males showed a positive allometry (b>1) while females a negative allometry (b<1). Fifty percent maturity of females (CW₅₀=58.87±0.14 mm) was significantly lower than that of males (CW₅₀=62.67±0.08 mm). Immature and mature crabs were recorded throughout the sampling period indicating that this species breeds throughout the year with a peak between September and November.

Length-weight relationships of 19 fish species from two tropical artificial reservoirs (Manantali and Selingue) in Mali, West Africa

Length-weight relationships (LWRs) were estimated for 19 fish species sampled from two artificial reservoirs (Manantali and Selingue) in Mali: Brycinus leuciscus, B. macrolepidotus, B. nurse, Chrysichthys auratus, C. nigrodigitatus, Coptodon zillii, Distichodus brevipinnis, D. rostratus, Hemichromis fasciatus, Hydrocynus forskahlii, Labeo coubie, L. senegalensis, Lates niloticus, Mormyrus rume, Sarotherodon galilaeus, Schilbe intermedius, S. mystus, Synodontis schall, S. sorex. The fish were collected between June 2002 and October 2003 during three experimental fishing campaigns using gillnets deployed overnight. All fish were measured (total length) to the nearest mm and weighed to the nearest g (total weight). Coefficients of determination of the LWRs (r²) were mostly high (> 0.9). The values of the allometry coefficient b ranged from 2.651 (Chrysichthys auratus) to 3.270 (Brycinus leuciscus). This study provides new information about LWRs of two fish species, which have been published but are not yet available in Fishbase (Distichodus brevipinnis and Mormyrus rume)

Length‐weight relationships for seven endemic fish species from streams of the last two large remaining dam‐free tributaries of the Upper Paraná River Floodplain in the Paraná State, Brazil

This study reports the length-weight relationships (LWR) for seven endemic fish species from streams in the Ivaí (Characidium heirmostigmata, Corydoras lacrimostigmata, Curculionichthys oliveirai, Hisonotus pachysarkos, and Cambeva horacioi) and Ivaí and Piquiri (Apareiodon vladii and Planaltina kaingang) River basins, Paraná State, Brazil. Fish specimens measured and weighed were collected between November 1994 and July 2019, fixed with 10% formalin, and are preserved in 70% alcohol. Measurements were done for standard length (SL—0.1 cm precision) and total weight (TW—0.01 g precision). All coefficient of allometry obtained is within the general range for fishes representing useful tentatives for LWR parameters. We highlight the importance of information about the biology of the endemic fish species in a crucial area for the biodiversity conservation of the Upper Paraná River system.

Understanding selected growth aspects in Redbelly Tilapia, Coptodon zilli (Gervais) and Largemouth Bass, Micropterus salmoides (Lacepède) in Lake Naivasha, Kenya; Fisheries Management Perspective

Coptodon zilli and Micropterus salmoides were introduced into Lake Naivasha in 1929 and 1959 respectively. The reasons for the introduction were to boost the fisheries and for recreational fishing respectively. However, the numbers of the two fish species in the lake have been declining over the years. It is therefore necessary to assess various aspects of their growth such as length-weight relationship, condition factor, sex ratio and length at first maturity to inform management and policy making for enhanced recovery and establishment of their populations. Length-weight relationship, condition factor, sex ratio and length at first maturity of the fish were studied from October 2016 to November 2018. A total of 303 fish samples; 193 C. zilli and 110 M. salmoides were studied. Results showed that C. zilli and M. salmoides had an allometry coefficient value of 2.9 and 3.1 and condition factor (K) value of 1.77 and 1.39 respectively. The sex ratios (male: female) of C. zilli and M. salmoides were 1.1:1 and 1.3: 1 respectively. The shortest total length for mature C. zilli and M. salmoides recorded were 12 cm and 26.5 cm while 21.8 cm and 51 cm were for the longest respectively. The fish growth pattern therefore failed to obey the cube law of b=3 thus exhibiting allometric growth. The two fish species were found to be in good condition with K factor above 1. It can therefore be concluded that the fish are generally in a good condition though the early maturity especially for C. zilli could be a sign of pressure either from environmental factors or human induced. Domination of the species by males, although a common feature in African lakes, is a case for concern since it presents uncertainty on the future of the fisheries. Restocking of Lake Naivasha with the two fish species should be considered and proper fishing practices enforced

Some aspects of fish growth in Redbelly Tilapia (Coptodon zilli) and Largemouth Bass (Micropterus salmoides) in Lake Naivasha, Kenya

Coptodon zilli and Micropterus salmoides were introduced into Lake Naivasha in 1929 and 1959 respectively. The reasons for introduction were to boost the fisheries and for recreational fishing respectively. However, the numbers of the two fish species in the lake have been declining over the years due to human activities and other ecological changes within the lake. Length-weight relationship, condition factor, sex ratio and length at first maturity of the fish were studied from October 2016 to November 2018. A total of 303 fish samples; 193 C. zilli and 110 M. salmoides were used in this study. Results showed that C. zilli and M. salmoides had an allometry coefficient value of 2.9 and 3.1 and K value of 1.77 and 1.39 respectively. The sex ratios (male: male) of C. zilli and M. salmoides were 1.1: and 1.3:1 respectively. The shortest total length for mature C. zilli and M. salmoides recorded were 12 cm and 26.5 cm while 21.8 cm and 51 cm were for the longest respectively. The fish growth pattern therefore failed to obey the cube low of b=3 thus exhibiting allomentric growth. The fish were in good condition with K factor above 1. It can therefore be concluded that the fish are generally in a good condition though the early maturity especially for C. zilli could be a sign of pressure either from environmental factors or as a result of overfishing within the lake. Investigations should be centered on breeding and population dynamics to better understand the two species within the lake.

Size and History Combine in Allometry Relation of Technology Systems

Complex systems often exhibit amazingly regular behavior through allometry relations (ARs) between their functional attributes and their size. An empirical allometry relation (EAR) between two properties of a complex system relates the average functionality [Formula: see text] and the average size [Formula: see text][Formula: see text] = a[Formula: see text] where the allometry coefficient a and allometry exponent b are empirical constants fit to data. This EAR is a static relation and is found in every sub-discipline of Natural History. Herein we establish, both empirically and theoretically, that for some classes of evolving technology systems, the empirical allometry coefficient a is not constant, but is strongly dependent on the historical time at which the technology system originated. Specifically, we construct an EAR with a time-dependent coefficient, using the evolution of a broad class of military systems, over the last ten centuries, ranging from a medieval bowman to a modern rifleman, from a horse-drawn cannon to a tank. This time-dependent EAR is derived from fundamental considerations involving complexity, scaling, and renormalization group theory. The theory entails an information as well as complexity generalization of the traditional allometry coefficient that combines system size with the technology knowledge of the new system’s developers (time-dependence). It relates technology ARs to technology evolution relations, such as Moore’s Law, with implications for technology drawn from biological evolution analysis.

The Effect of Priming on Germination Characteristics of Barley Seeds under Drought Stress Conditions

Seed priming methods have been used to increase germination and seedling establishment under different abiotic stress conditions. Seed priming was used in barley to increase seed germination and tolerance on stress exposure. Barley seeds were treated with various priming agents for different time and temperatures. The effect of priming was assessed on germination characteristics on subsequent exposure to drought (PEG-12 bar) stress for 7 days. Seed priming treatments significantly (p≤ 0.01) affected germination percentage (GP), normality seedling percentage (NSP), germination Index (GI), germination uniformity (GU), means time to germination (MTG), coefficient of velocity of germination (CVG), seedling vigor index (SVI) and coefficient of allometry (AC). Seed priming with gibberelic acid (GA), salicylic acid (SA), ascorbic acid (ASc), hydropriming (HP), osmopriming (OP) and combined treatments (CT) significantly (p≤ 0.01) increased germination characteristics, compared to the unprimed. Seed priming with concentrations 25, 50 ppm of GA for 15 h at 10°C, 25 ppm of SA for 12 h at 10°C, 50 ppm of ASc for 12 h at 15°C, treatment 16 h hydropriming at 10°C and -15 bar PEG for 24 h for osmopriming may be considered as optimal treatment for priming of barley seeds in drought stress conditions. In some cases, combined treatments are better than the separate treatments. Seed priming with PEG (potential -l5 bar PEG for 24 h at 10°C) was more effective in drought stress than the other treatments.