scholarly journals Growth rates are related to production efficiencies in juveniles of the sea urchin Lytechinus variegatus

2013 ◽  
Vol 93 (6) ◽  
pp. 1673-1683 ◽  
Author(s):  
L.E. Heflin ◽  
V.K. Gibbs ◽  
W.T. Jones ◽  
R. Makowsky ◽  
A.L. Lawrence ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Production Efficiency ◽  
Sea Urchins ◽  
High Growth ◽  
Dietary Treatment ◽  
Lytechinus Variegatus ◽  
Wet Weight ◽  
Dietary Treatments ◽  
Production Efficiencies

Growth rates of newly-metamorphosed urchins from a single spawning event (three males and three females) were highly variable, despite being held en masse under identical environmental and nutritional conditions. As individuals reached ~5 mm diameter (0.07–0.10 g wet weight), they were placed in growth trials (23 dietary treatments containing various nutrient profiles). Elapsed time from the first individual entering the growth trials to the last individual entering was 121 days (N = 170 individuals). During the five-week growth trials, urchins were held individually and proffered a limiting ration to evaluate growth rate and production efficiency. Growth rates among individuals within each dietary treatment remained highly variable. Across all dietary treatments, individuals with an initially high growth rate (entering the study first) continued to grow at a faster rate than those with an initially low growth rate (entering the study at a later date), regardless of feed intake. Wet weight gain (ranging from 0.13–3.19 g, P <0.0001, R2 = 0.5801) and dry matter production efficiency (ranging from 25.2–180.5%, P = 0.0003, R2 = 0.6162) were negatively correlated with stocking date, regardless of dietary treatment. Although canalization of growth rate during en masse early post-metamorphic growth is possible, we hypothesize that intrinsic differences in growth rates are, in part, the result of differences (possibly genetic) in production efficiencies of individual Lytechinus variegatus. That is, some sea urchins are more efficient in converting feed to biomass. We further hypothesize that this variation may have evolved as an adaptive response to selective pressure related to food availability.

Biology of Gadus morhua in Ogac Lake, a Landlocked Fiord on Baffin Island

1967 ◽  
Vol 24 (12) ◽  
pp. 2573-2594 ◽  
Author(s):  
David G. Patriquin
Keyword(s):  
Growth Rates ◽  
Gadus Morhua ◽  
Environmental Variability ◽  
Sea Urchins ◽  
High Growth ◽  
Baffin Island ◽  
Meristic Characters ◽  
Large Size ◽  
Fin Ray ◽  
High Length

Gadus morhua L. occurs in Ogac Lake, a salt, meromictic lake on Baffin Island that receives influxes of seawater only during the highest summer tides. Cod of the order of 10,000 of lengths 25 cm and greater and 500 of lengths greater than 60 cm were present. The size ranges for various ages far exceeded those of oceanic populations. Feeding conditions were poor, and sea urchins predominated in the diet. Large cod (greater than 50 cm) were highly cannibalistic, and it was estimated that they consume of the order of 3500 fish of 20–40 cm annually. Maturation occurred at the unusually large size of 85 cm in females, and at about 65 cm in males. Apparently many of the cod never reach these sizes. Spawning was from late May to early July in 1962, and initiation of spawning appeared to be related to light. The hatching of cod larvae coincided with the appearance of the nauplii of the dominant copepod in the lake. Egg size was highly variable and exhibited a curious bimodalism. Variation in vertebral and fin-ray counts was slight in spite of high environmental variability, and thus appears largely genetically controlled. Possibly the first inhabitants came from Greenland stocks, which have high growth rates similar to the faster growing cod in the lake, and similar high length at maturity. Meristic characters also suggest affinity with Greenland rather than Labrador cod. The hydrography of the area and the possibilities of larval drift or adult migration into the lake are discussed. Cannibalism must exert continuing selection for high growth rates, but very poor feeding conditions and hierarchial dominance effects probably prevent general attainment of high growth rates.

Very High Growth Rate of 4H-SiC Using MTS as Chloride-Based Precursor

2008 ◽  
Vol 600-603 ◽  
pp. 115-118 ◽  
Author(s):  
Henrik Pedersen ◽  
Stefano Leone ◽  
Anne Henry ◽  
Franziska Christine Beyer ◽  
Vanya Darakchieva ◽  
...  
Keyword(s):  
Growth Rate ◽  
Linear Dependence ◽  
Growth Rates ◽  
Molar Fraction ◽  
High Growth ◽  
High Growth Rate ◽  
Epitaxial Layers ◽  
Single Precursor ◽  
Very High

The chlorinated precursor methyltrichlorosilane (MTS), CH3SiCl3, has been used to grow epitaxial layers of 4H-SiC in a hot wall CVD reactor, with growth rates as high as 170 µm/h at 1600°C. Since MTS contains both silicon and carbon, with the C/Si ratio 1, MTS was used both as single precursor and mixed with silane or ethylene to study the effect of the C/Si and Cl/Si ratios on growth rate and doping of the epitaxial layers. When using only MTS as precursor, the growth rate showed a linear dependence on the MTS molar fraction in the reactor up to about 100 µm/h. The growth rate dropped for C/Si < 1 but was constant for C/Si > 1. Further, the growth rate decreased with lower Cl/Si ratio.

scholarly journals Rapid Growth of UropathogenicEscherichia coliduring Human Urinary Tract Infection

mBio ◽  
2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Valerie S. Forsyth ◽  
Chelsie E. Armbruster ◽  
Sara N. Smith ◽  
Ali Pirani ◽  
A. Cody Springman ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Urinary Tract ◽  
Growth Rates ◽  
High Growth ◽  
Replication Forks ◽  
Chromosomal Replication ◽  
E Coli ◽  
Tract Infections

ABSTRACTUropathogenicEscherichia coli(UPEC) strains cause most uncomplicated urinary tract infections (UTIs). These strains are a subgroup of extraintestinal pathogenicE. coli(ExPEC) strains that infect extraintestinal sites, including urinary tract, meninges, bloodstream, lungs, and surgical sites. Here, we hypothesize that UPEC isolates adapt to and grow more rapidly within the urinary tract than otherE. coliisolates and survive in that niche. To date, there has not been a reliable method available to measure their growth ratein vivo. Here we used two methods: segregation of nonreplicating plasmid pGTR902, and peak-to-trough ratio (PTR), a sequencing-based method that enumerates bacterial chromosomal replication forks present during cell division. In the murine model of UTI, UPEC strain growth was robustin vivo, matching or exceedingin vitrogrowth rates and only slowing after reaching high CFU counts at 24 and 30 h postinoculation (hpi). In contrast, asymptomatic bacteriuria (ABU) strains tended to maintain high growth ratesin vivoat 6, 24, and 30 hpi, and population densities did not increase, suggesting that host responses or elimination limited population growth. Fecal strains displayed moderate growth rates at 6 hpi but did not survive to later times. By PTR,E. coliin urine of human patients with UTIs displayed extraordinarily rapid growth during active infection, with a mean doubling time of 22.4 min. Thus, in addition to traditional virulence determinants, including adhesins, toxins, iron acquisition, and motility, very high growth ratesin vivoand resistance to the innate immune response appear to be critical phenotypes of UPEC strains.IMPORTANCEUropathogenicEscherichia coli(UPEC) strains cause most urinary tract infections in otherwise healthy women. While we understand numerous virulence factors are utilized byE. colito colonize and persist within the urinary tract, these properties are inconsequential unless bacteria can divide rapidly and survive the host immune response. To determine the contribution of growth rate to successful colonization and persistence, we employed two methods: one involving the segregation of a nonreplicating plasmid in bacteria as they divide and the peak-to-trough ratio, a sequencing-based method that enumerates chromosomal replication forks present during cell division. We found that UPEC strains divide extraordinarily rapidly during human UTIs. These techniques will be broadly applicable to measurein vivogrowth rates of other bacterial pathogens during host colonization.

An analysis of growth of different cattle genotypes reared in different environments

1984 ◽  
Vol 103 (1) ◽  
pp. 137-153 ◽  
Author(s):  
J. E. Frisch ◽  
T. E. Vercoe
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
High Growth ◽  
Environmental Stresses ◽  
Growth Potential ◽  
Gastrointestinal Helminths ◽  
Treatment Groups ◽  
Survival And Growth ◽  
Different Levels ◽  
High Growth Potential

SummaryCalves from three breeds, Brahman, Hereford × Shorthorn (HS) and Brahman × HS (BX), were divided equally into two groups, one of which was treated every 3 weeks from birth onwards to control ticks and gastrointestinal helminths, and one of which was untreated. Mortalities, growth rates and levels of resistance to environmental stresses that affected both mortality and growth under grazing conditions were recorded for all animals up to weaning (6 months) and for all males up to 15 months of age. The Brahmans were the most and the HS were the least resistant to environmental stresses, each of which was shown to depress growth in proportion to its magnitude and to contribute to the high mortalities of the HS. All breeds responded positively to parasite control with the greatest response in both survival and growth in the HS breed and the least response in the Brahman breed.Samples of males from the various breed-treatment groups were taken into pens where they were protected from environmental stresses and fed both low-quality pasture hay and high-quality lucerne hay ad libitum. Measurements were made of fasting metabolism, maintenance requirement, voluntary food intake and gain, variables related to the growth potential of each animal. The HS animals had the highest whilst the Brahmans had the lowest values for each variable.However, despite their low growth potential, the Brahmans had the highest growtli rate, and the HS, despite their high growth potential, had the lowest growth rate, when growth was measured in the presence of all environmental stresses. When parasites were controlled, growth rates were highest for the BX, the breed with intermediate growtli potential, and did not differ between the HS and Brahmans. These interactions arose because of the different contributions of resistance to environmental stresses and growth potential to growth rate measured at the different levels of environmental stresses. The relevance of these interactions to breed evaluation and cross-breeding is considered.Growth potential and resistance to environmental stresses were negatively correlated both between and within breeds, though the latter was biased by the effects of compensation. The influence of these relationships on the likely outcome of selection for increased growth rate, both between and within breeds, is discussed.

Relationship between bone growth rate and bone tissue organization in amniotes: first test of Amprino's rule in a phylogenetic context

2010 ◽  
Vol 60 (1) ◽  
pp. 25-41 ◽  
Author(s):  
Jacques Castanet ◽  
Jorge Cubo ◽  
Laëtitia Montes
Keyword(s):  
Growth Rate ◽  
Bone Tissue ◽  
Growth Rates ◽  
Bone Growth ◽  
Phylogenetic Signal ◽  
Variation Partitioning ◽  
High Growth ◽  
Tissue Organization ◽  
Shared Ancestry ◽  
Functional Factors

AbstractA debate on the determinism (phylogenetic versus functional) of the diversity of bone histological features has centred the interest of bone comparative biologists. While some authors have noticed the presence of a phylogenetic signal in bone tissue variation, many others have argued that these characters may not include much phylogenetic information, but rather reflect functional factors. Here we quantify both components in a sample of amniotes. We hypothesize that: 1/ the observed variation is partly the outcome of shared ancestry (phylogenetic factor) and 2/ for a given quantity of bone produced, tissues formed at a rapid rate may have a higher fraction of vascular cavities than those produced at a slower rate (functional factor). Variation partitioning analyses show that the phylogeny explains a significant portion of the variation of bone vascularity (85.3%), bone growth rate also explains a significant portion of this variation (68.3%), and there is an important overlap (67.9%). Finally, an optimization through least-squares parsimony of bone growth rates onto the phylogeny shows that the most important evolutionary change may have occurred after the split between crocodiles and birds. This change may be linked to the origin of avian endothermic metabolism because high growth rates involve high protein turnover, which is very energy consuming. We conclude that the debate on the dichotomy between phylogenetic versus functional causation of bone histological diversity is misleading, because we have shown that bone vascularity has, at the same time, a functional significance and a phylogenetic signal.

scholarly journals Growth of Output and Productivity in Pakistan’s Agriculture: Trends, Sources, and Policy Implications

1996 ◽  
Vol 35 (4II) ◽  
pp. 527-536 ◽  
Author(s):  
M.Ghaffar Chaudhry ◽  
Ghulam Mustafa Chaudhry ◽  
Muhammad Ali Qasim
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Commodity Prices ◽  
High Growth ◽  
Price Policy ◽  
Policy Implications ◽  
Open Market ◽  
Agricultural Commodity ◽  
Average Growth ◽  
Negative Effect

The paper aims to review the growth performance of Pakistan’s agriculture from 1950 to 1995. The long-term growth rate of agriculture, although respectable, has exhibited considerable yearly fluctuations even between decades. The period of the fifties and early seventies lacked any growth. Accelerating and high growth rates marked the decade of the sixties but the performance has not been satisfactory since 1979-80 and average growth rates have barely exceeded the population growth rate, with widespread implications for growth of national economy, food security, and social welfare of the masses. Area, modern inputs, and technology have been the major determinants of growth but prices were equally important because of their incentive and disincentive effects. The agriculture price policies adopted during the 1980s are known to have had a negative effect on the development and use of technology in agriculture. In order to boost agricultural productivity, a change in price policy is needed to ensure incentive prices. This could be done by setting agricultural commodity prices at par with corresponding import and export parity prices. A higher investment in research and development can hardly be overemphasised. There is an urgent need to remove the bottlenecks in agricultural input markets since these markets represent the typical monopoly position. To break up the monopoly of registered dealers and to promote competition, free sales in the open market by interested parties and individuals may be allowed.

scholarly journals Evaluation of Correlation between Labour Productivity and Wages in Individual Countries’ Economy

2020 ◽  
Vol 164 ◽  
pp. 11029
Author(s):  
Irina Bogatyreva ◽  
Larisa Ilyukhina
Keyword(s):  
Growth Rate ◽  
Real Time ◽  
Productivity Growth ◽  
Growth Rates ◽  
Production Efficiency ◽  
Labour Productivity ◽  
Digital Economy ◽  
Production Costs ◽  
Strategic Development ◽  
Labour Productivity Growth

The paper is concerned with the problems of evaluating and managing the correlation between labour productivity growth and wages as the most important elements of strategic development of economies in different world countries. A judicious correlation between the growth rate of labour productivity and wages affects the reduction of production costs, increase of profitability, and improvement of production efficiency. This explains the relevance of the study to evaluate interconnection between labour productivity and wages in the digital economy. The authors presented the research results of the dynamics of labour productivity and wages for individual countries in real time of 2014-2018, calculated indicators of the correlation between growth rates of average wages in the countries’ economy, described models, and developed the mechanism to manage the correlation between labour productivity and wages.

The effect of growth rate on muscle distribution in sheep

1975 ◽  
Vol 85 (1) ◽  
pp. 189-191 ◽  
Author(s):  
D. M. Murray ◽  
Olga Slezacek
Keyword(s):  
Growth Rate ◽  
Weight Loss ◽  
Growth Rates ◽  
Live Weight ◽  
High Growth ◽  
Growth Path ◽  
Merino Sheep ◽  
Reported Data ◽  
Relationship Of ◽  
The Relationship

There is little information available on the effect of growth rate on muscle distribution in sheep. Although Lohse, Moss & Butterfield (1971) and Lohse (1973) have reported data on muscle distribution of Merino sheep, the growth rates of animals in both these studies were neither controlled nor reported. In another experiment using Merino sheep, Lohse, Pryor & Butterfield (1973) studied the effect of a period of live-weight loss on the relationship of selected muscles to total side muscle during subsequent re-alimentation. They found that the interrupted growth path decreased the proportion of total side muscle formed by the weight of ten muscles which had previously been classified as muscles with a high growth impetus (Lohse, 1971). Data are presented herein for the muscle distribution of sheep grown along three growth paths.

scholarly journals Domain Structure of Thick GaN Layers Grown by Hydride Vapor Phase Epitaxy

1999 ◽  
Vol 4 (S1) ◽  
pp. 197-202
Author(s):  
T. Paskova ◽  
E.B. Svedberg ◽  
L.D. Madsen ◽  
R. Yakimova ◽  
I.G. Ivanov ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
High Growth ◽  
Vapour Phase ◽  
Hydride Vapor Phase Epitaxy ◽  
Spiral Growth ◽  
Structural Quality ◽  
Vapour Phase Epitaxy ◽  
Force Microscopy ◽  
Atomic Force

The crystal structure and surface morphology of hydride vapour phase epitaxy grown thick (12-105 μm) GaN layers have been investigated as a function of growth rate using several structure sensitive techniques like atomic force microscopy (AFM), x-ray diffraction (XRD) in ω-2θ and ω-rocking curve measurements as well as low temperature photoluminescence (PL). PL and XRD measurements reveal rather narrow lines: full width at half maximum (FWHM) values of the strongest donor-bound exciton line are in the range from 6.0 to1.8 meV and ω-2θ FWHM values are between 80 and 23 arcsec indicating good structural quality of the films. The ω-rocking curves show a single peak for the thinnest films with a FWHM of 250 arcsec and multiple peaks with FWHM of about 250-350 arcsec in thicker films indicating the formation of several high-quality domains when increasing either thickness or growth rate. Optical microscopy and AFM images reveal a domain type of morphology and also show an appearance of spiral hillocks in layers grown at growth rates exceeding a critical value. We interpret these results as dominating 2D multilayer growth at low growth rates, and competing 2D multilayer and spiral growth mechanisms at high growth rates.

scholarly journals Do Growing Rabbits with a High Growth Rate Require Diets with High Levels of Essential Amino Acids? A Choice-Feeding Trial

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 824
Author(s):  
Pablo Jesús Marín-García ◽  
Mari Carmen López-Luján ◽  
Luís Ródenas ◽  
Eugenio Martínez-Paredes ◽  
María Cambra-López ◽  
...  
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Amino Acid ◽  
Growth Rates ◽  
Nutrient Retention ◽  
High Growth ◽  
Feeding Trial ◽  
Nutritional Recommendations ◽  
Sulphur Amino Acids ◽  
Choice Feeding

As a consequence of the genetic selection process in growing rabbits, there are currently fast-growing animals exhibiting an average daily gain that may exceed 45 g/d. The protein requirements of these animals, namely amino acid requirements, may differ from animals with low growth rates. The objective of this work was to evaluate growth performance, the coefficient of total tract apparent digestibility (CTTAD), the apparent ileal digestibility (AID) of amino acids and nutrient retention of fast-growing rabbits when they had access to a diet with high levels of amino acids and/or a diet formulated with current nutritional recommendations in a choice-feeding trial. To this end, two diets were formulated: the M diet following current nutritional recommendations for growing rabbits (including 8.1, 5.8 and 6.9 g/kg dry matter (DM) of total lysine, sulphur amino acids and threonine, respectively) and the H diet with higher levels of total lysine, sulphur amino acids and threonine (9.4, 6.6 and 7.8 g/kg DM, respectively). A total of 220 weaned rabbits, from a paternal line selected for the growth rate, had free access to the M diet, the H diet or both (MH) diets from 28 to 63 days of age. The CTTAD of DM, crude protein and gross energy from 49 to 53 days of age as well as the AID of amino acids of the diets at 63 days of age were determined. Protein, amino acids and energy retained in the empty body from 28 to 63 days of age were also registered. No significant differences in growth performance, CTTAD, AID and nutrient retention between dietary treatments were observed. However, animals fed the H diet showed a higher AID of cysteine (p < 0.05) and higher threonine retention (p < 0.05) compared to the M diet. As regards the choice-feeding trial, MH animals showed a higher feed intake of the M diet compared to the H diet (+8.61%; p < 0.001), and furthermore, more than 50% of the animals preferred the M diet throughout the experimental period (p < 0.05). Our results suggest that animals with high growth rates do not show significantly higher productive traits when fed the H diet compared to the M diet. As regards choice feeding, MH animals were capable of choosing their preferred diet, showing high intra-individual repeatability in preference for the M diet. It would be interesting to continue studying this behaviour of choice based on amino acid levels.

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