Determination Of Growth Rate Research Articles

Effects of a dry pelleted diet on growth and survival of the Yucatan octopus, Octopus maya

The effect of a dry pelleted diet on growth of the Yucatan octopus (Octopus maya) was determined and compared with crab diet (Callinectes spp). Two groups of 15 wild collected animals were used. Octopuses were placed in isolation, in a flow-through system composed of 30 circular tanks (80 L), with a bottom of 40 cm in diameter and a water depth of 80 cm. Experiment lasted 40 days, and octopuses were weighed every 10 days to determine growth rates. Octopuses were fed between 7% and 10% body weight (BW) per day, twice a day at 9:00 h and 17:00 h. Uneaten food was removed after 4 h in the tanks and weighed, to determine food ingestion and conversion. No mortality as a result of natural causes was observed. The 15 octopuses fed on frozen crabs and the 15 fed on the artificial diet had similar weights (P > 0.05) at the start of the experiment, of 486.2 ± 214.8 and 472.5 ± 228.3 g, respectively. At the end of the experiment, octopuses fed on frozen crabs weighed 1466.5 ± 484.0 g, and were significantly larger (P < 0.05), than octopuses fed on artificial diets (438.9 ± 202.6 g). Growth rates for the experiment were of 3.3 ± 0.2 and –0.0 ± 0.3% BW per day, for octopuses fed frozen crabs and the artificial diet, respectively. The artificial diet did not promote growth, but animals did not loose weight and more important, ate regularly all the food supplied, with feeding rates higher than reported in the literature for prepared diets. This makes O. maya a good research animal for the development of artificial diets for cephalopods.

Expression and activation of mTOR in neuroendocrine tumors. Effects of mTOR inhibition by RAD001 upon growth, cell cycle regulation and signalling in neuroendocrine cell lines

10570 Background: Molecular pathogenesis of neuroendocrine tumors of the digestive tract is largely unknown. We examined paraffin sections of different types of neuroendocrine tumors for expression of activated kinases involved in regulation of growth and protection against apoptosis. In addition, we studied effects of a newly developed inhibitor of mTOR (RAD001) upon growth, cell cycle regulation and signaling in two different neuroendocrine cell lines. Methods: Immunohistochemistry with antibodies for native and activated signaling kinases was performed on paraffin sections. MTT assays were used to determine growth rates of neuroendocrine cell lines and FACS analysis was performed for cell cycle analysis. Immunoblotting revealed activation of kinases. Results: Extracellular activated kinase 1/2 (ERK1/2), cAMP regulated element binding protein (CREB), protein kinase B (PKB) and mTOR were expressed in the majority of insulinomas (n = 40) and serotonin-producing neuroendocrine tumors (carcinoids, n = 49). Phosphorylated forms of these kinases corresponding to their activated state were also detected in these tumors. Most neuroendocrine tumors expressed high levels of activated CREB, PKB and mTOR whereas phosphorylated ERK1/2 was present only a minority of dNETs. Inhibition of mTOR kinase by different concentrations of RAD001 induced growth arrest in insulinoma (INS-1) and human neuroendocrine serotonin-producing cells (BON) in concentrations between 10 and 100 nM. Interestingly, we observed pronounced synergism between octrotide and RAD001 upon growth inhibition in these cell lines. Growth inhibition by RAD001 corresponded to decreased S-phase and increased G0/G1 peak in cell cycle analysis. RAD001 inhibited effectively phosphorylation of mTOR with an IC50 of 10 nM. However, we observed only minor inhibition of PKB and CREB by RAD001 and partial inhibition of ERK signaling by RAD in concentrations between 100 nM and 1 μM. Conclusions: mTOR is expressed and activated in different neuroendocrine tumors and inhibition of mTOR by RAD001 induces growth inhibition, cell cycle arrest and decreased signaling by mTOR and ERK1/2 in neuroendcrine cell lines INS-1 and BON. No significant financial relationships to disclose.

Imaging of peripheral nerve tumors

Recent advancements in the field of imaging, particularly magnetic resonance imaging, have improved the way peripheral nerve tumors are diagnosed, monitored, and treated both medically and surgically. When combined with the all-important clinical evaluation and electrodiagnostic studies, imaging permits a clinician to accomplish the following: identify the size, shape, location, and distribution of mass lesions; infer the risks in resecting a mass lesion by displaying its relationship to nearby nerve fascicles; determine growth rates when serial imaging studies are available; suggest the nature of the pathological entity; and visualize muscle denervation associated with nerve damage. The authors describe some of the commonly used imaging modalities and discuss their use in evaluating and treating peripheral nerve tumors and other mass lesions.

Growth, survival and inactivation of Pseudomonas aeruginosa and Staphylococcus aureus strains of various origin in the presence of ethanol

The influence of ethanol on the behaviour of Pseudomonas aeruginosa and Staphylococcus aureus strains was evaluated throughout this study. Strains of different origin were used: collection, clinical and industrial strains were selected. Concentrations of ethanol from 0 to 20% (v/v) were evaluated by automated optical density measurements and by enumeration. When growth conditions were observed, predictive microbiology models were used to assess quantitatively for the ethanol effect. Primary modelling of kinetics was performed to determine growth rate values; secondary modelling was performed on these growth rates as influenced by ethanol, and minimum inhibitory concentrations of ethanol were determined for each strain. Staphylococcus aureus strains were more resistant to ethanol than P. aeruginosa strains, in growth conditions as well as in inactivation conditions. Furthermore, clinical S. aureus strains were more resistant than the collection strain. The method was promising for management of microbiological safety in cosmetics.

Precipitation of αl-glutamic acid: determination of growth kinetics

Growth kinetics of alpha L-glutamic acid was determined based on seeded batch desupersaturation experiments. The growth rate correlation applied in this study accurately describes the growth process in a temperature range of 25-45 degrees C and in a supersaturation range of 1-3. The newly developed approach for the growth rate characterization has the advantage of a high robustness especially with respect to the influence of competing particle formation mechanisms as nucleation or agglomeration. The efficient technique employs in situ process analytical technologies, e.g. attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and focused beam reflectance measurement (FBRM), different ex situ analytical tools and population balance modeling combined with a non-linear least squares optimization algorithm to determine the growth kinetics. The growth mechanism was identified to be integration controlled and of birth and spread (B + S) type. The quality of the determined growth rate correlation was assessed by comparison with the experimental data and with literature data.

Growth of Age-0 Steelhead (Oncorhynchus mykiss) and Brook Trout (Salvelinus fontinalis) in the Pine River Watershed, Alcona County, Michigan

ABSTRACT We sampled ten sites within the Pine River watershed, Alcona County, Michigan. In 2001, age-0 steelhead (Oncorhynchus mykiss) were collected to determine growth rates. In 2002, emergence dates of steelhead were determined by observational studies and age-0 steelhead and brook trout (Salvelinus fontinalis) were collected to determine growth rates. Steelhead emergence occurred from late June to mid-July 2002. Growth rates of both species varied among branches within the watershed (P<0.05). Steelhead growth varied from 0.24 to 0.42 mm/day and brook trout growth varied from 0.22 to 0.37 mm/day.

Modeling ammonothermal growth of GaN single crystals: The role of transport

Single crystal gallium nitride (GaN) is an important technological material used primarily for the manufacture of blue light lasers. An important area of contemporary research is developing a viable growth technique. The ammonothermal technique is an important candidate among many others with promise of commercially viable growth rates and material quality. The GaN growth rates are a complicated function of dissolution kinetics, transport by thermal convection and crystallization kinetics. A complete modeling effort for the growth would involve modeling each of these phenomena and also the coupling between these. As a first step, the crystallization and dissolution kinetics were idealized and the growth rates as determined purely by transport were investigated. The growth rates thus obtained were termed ‘transport determined growth rates’ and in principle are the maximum growth rates that can be obtained for a given configuration of the system. Using this concept, a parametric study was conducted primarily on the geometric and the thermal boundary conditions of the system to optimize the ‘transport determined growth rate’ and determine conditions when transport might be a bottleneck.

On the reproduction and growth of some endemic gastropods of Lake Baikal

Reproduction and ontogeny of some Baikalian gastropods inhabiting the littoral were studied. To detect phases of enhanced hatching, growth and production of fresh egg capsules, SCUBA divers lifted stones from the littoral of the western shore of Lake Baikal and from River Angara monthly. All egg capsules and gastropods were recorded. Four different developmental phases of embryos were distinguished. In March the percentage of egg capsules with fully developed embryos is very high, but in April–June the percentage rapidly decreases due to enhanced hatching and a high production of newly laid capsules. From June to October the proportion of older developmental stages increases again. Freshly laid capsules were found at any time, but in March–April, the percentage is low while it is high from May to July. Embryogenesis does not take a few weeks as in most Palaearctic species but several months. Although embryos were found fully developed in autumn–winter, most hatching occurs in spring. In order to determine growth rate and time to maturity for different endemic gastropods, juveniles were kept in rearing cages in situ. The cages were lifted monthly and the snails measured. Results showed growth is very low from November to May and maximal in the period August to October. Thus, shell growth is not steady but cyclical. Compared with relatived species inhabiting smaller Palaearctic water bodies, the ontogeny of Baikalian gastropods is prolonged. It appears that in Lake Baikal Megalovalvata needs 2 years and Choanomphalus 2–3 years to become mature, while the Baicaliidae need at least 4 years to mature and 5 years to be fully grown. Growth rates are higher in the Angara River than in the Lake Baikal littoral.

Pediatric Feeding Disorder and Growth Decline following Mandibular Distraction Osteogenesis

Mandibular distraction osteogenesis has proven to be an effective treatment for upper airway obstruction related to micrognathia. Changes in the aerodigestive space can help facilitate tracheostomy removal in children and prevent tracheostomy in newborns. However, this may also precipitate changes in the ability to orally feed. There are few data on early postoperative feeding and growth rate following mandibular lengthening. The authors found evidence of growth rate decline and feeding difficulty in pediatric patients following mandibular distraction osteogenesis. Ten pediatric patients underwent mandibular distraction osteogenesis for treatment of upper airway obstruction. Outcomes in resolution of upper airway obstruction, oral feeding success, and growth rate were analyzed. Follow-up ranged from 12 to 28 months. All 10 patients had complete resolution of upper airway obstruction. The length of distraction ranged from 10 to 17 mm. Three patients demonstrated a feeding disorder after mandibular distraction osteogenesis, defined as requiring a long-term (>1 month) alternate feeding method (gastric tube in two patients and gastric gavage in one). Seven of 10 patients exhibited an early decline in growth rate following distraction. Data used to determine growth rate changes were weight measurements at the time of distraction, at the time of distractor removal (6 to 8 weeks after distraction), and at 6 and 12 months after the date of distraction initiation. These results suggest that infants and children undergoing mandibular lengthening by distraction osteogenesis should be carefully monitored for postdistraction feeding disorder and growth rate disturbance.

Changes in Diet and Food Consumption of Largemouth Bass Following Large-scale Hydrilla Reduction in Lake Seminole, Georgia

Largemouth bass Micropterus salmoides Lacepede growth (in length) increased an average of 14% and bioenergetics modeling predicted a 38% increase in total annual food consumption following a large-scale reduction of hydrilla Hydrilla verticillata L.f. Royle in Spring Creek, a 2,343-ha embayment of Lake Seminole, Georgia. Coverage of submersed aquatic vegetation (SAV) declined from 76% to 22% in 1 year due to a drip-delivery fluridone treatment. In contrast, largemouth bass growth only increased an average of 4% and bioenegetics modeling predicted a 13% increase in total food consumption over the same time period in the Chattahoochee River embyament, where SAV coverage naturally declined from 26% to 15%. Diets were collected from a total of 4,409 largemouth bass over a 2.5-year period in the two embayments; the primary diet item (by weight) for largemouth bass in both embayments was sunfish (mostly Lepomis spp.). Diets before and after SAV reduction were generally similar for fish greater than stock-size (≥203 mm) in the Spring Creek arm; however, fewer invertebrates were consumed after SAV reduction. Low diet similarity was observed in smaller fish, caused by a decline in consumption of grass shrimp and sunfishes and an increase in use of damselflies, shiners Notropis spp., and topminnows Fundulus spp. after SAV reduction. Diets were similar between the same time periods for all sizes of fish in the Chattahoochee River arm. These results agreed with many laboratory results describing the effects of aquatic plant density on largemouth bass food consumption and growth, and demonstrated that increased predation efficiency resulting from decreased plant abundance was likely a stronger factor determining growth rates than any potential diet shift that may occur as a result in vegetation decline.

GROWTH RATE AND LONGEVITY OF DREISSENA POLYMORPHA (PALLAS): A REVIEW AND RECOMMENDATIONS FOR FUTURE STUDY

We review the variety of methods that have been used over the last 50 y in the Former Soviet Union, Eastern and Western Europe, and recently in North America to determine growth rate and longevity in zebra mussels (Dreissena polymorpha [Pallas]). These methods include: counting annual rings, analysis of size-frequency distributions, following growth under experimental conditions and monitoring marked mussels under natural conditions, without removing them from substrate. The last method provides the most reliable data, however this is the least common method used. Dreissena polymorpha growth rates depend on water temperature, season of the year, location in the water column, food availability, oxygen concentrations, water velocity and various other environmental factors. However, it is very difficult to separate the independent effects of each of these factors, especially in natural waterbodies. Several factors may overlap and have additive or synergistic effect that makes it difficult to determine the effects of a single factor. When comparing among studies that used the same methods, we found that zebra mussels grow faster in reservoirs than in lakes. The reported longevity of D. polymorpha varies from 2–19 y and it is not clear to what extent this variation is caused by biological variability and environmental conditions and what amount of the variation is caused by the methods used to assess age and longevity.

Physiological bases of genetically determined variation in growth of marine invertebrate larvae: A study of growth heterosis in the bivalve Crassostrea gigas

Many species of marine animals have larval stages whose rates of growth in the plankton are regulated by complex combinations of biological and environmental factors. In this study, we focus on the physiological bases that underlie endogenous variation in growth potential of larvae. Our approach was based on experimental crosses of gravid adults from pedigreed families of the Pacific oyster, Crassostrea gigas. This produced large numbers of larvae with different growth rates when reared under similar environmental conditions of food and temperature. A total of 35 larval families were reared to test hypotheses regarding the physiological bases of growth variation. Growth rate of these larval families varied over a five-fold range, from 3.4 (± 0.5, S.E.) to 17.6 (± 0.6) μm day − 1 . The suite of integrated measurements applied to study growth variation included size, biochemical compositions, rates of particulate and dissolved nutrient acquisition, absorption efficiencies, respiration rates and enzyme activities. We show that a complex set of physiological processes regulated differences in genetically determined growth rates of larvae. One-half of the energy required for faster growth came from an enhanced, size-specific feeding ability. Differences in absorption rates were not significant for slow- and fast-growing larvae, nor were differences in size-specific respiration rates. Metabolic processes accounted for the additional 50% of the energy “savings” required to explain enhanced growth rates. We propose that different protein depositional efficiencies could account for this energy saving. Quantitative analyses of the endogenous physiological factors that cause variation in growth rate will allow for a more sophisticated understanding of growth, survival and recruitment potential of larvae.

Maternal programming of defensive responses through sustained effects on gene expression

There are profound maternal effects on individual differences in defensive responses and reproductive strategies in species ranging literally from plants to insects to birds. Maternal effects commonly reflect the quality of the environment and are most likely mediated by the quality of the maternal provision (egg, propagule, etc.), which in turn determines growth rates and adult phenotype. In this paper we review data from the rat that suggest comparable forms of maternal effects on defensive responses stress, which are mediated by the effects of variations in maternal behavior on gene expression. Under conditions of environmental adversity maternal effects enhance the capacity for defensive responses in the offspring. In mammals, these effects appear to ‘program’ emotional, cognitive and endocrine systems towards increased sensitivity to adversity. In environments with an increased level of adversity, such effects can be considered adaptive, enhancing the probability of offspring survival to sexual maturity; the cost is that of an increased risk for multiple forms of pathology in later life.

Environmental determinants of growth rates for larval Japanese anchovy Engraulis japonicus in different waters

AbstractDo disparate mechanisms determine growth rates of fish larvae in the different regions? The relationship between growth rates and environmental factors (sea temperature and food availability) was examined for larval Japanese anchovy Engraulis japonicus in geographically and environmentally different waters, through sagittal otolith microstructure analysis. Recent 3‐day mean growth rates directly before capture were positively related with sea‐surface temperature (SST) but not with food availability (plankton density) for the larvae in the Kuroshio Extension and Kuroshio–Oyashio transition regions of the western North Pacific. On the contrary, variations in recent growth rates were attributed to food availability (plankton density) as well as SST for the larvae in the East China Sea. In the shirasu fishing ground in Sagami Bay, larval growth rates were variable under the influences of both SST and food availability (feeding incidence). On the surface, the growth–environment relationships seemed to differ among regions. However, a definite general pattern of the dome‐shaped relationship between recent growth rates and SST was observed when all the regions were combined. Growth rates were similar even among clearly different regions if at the same SST. Overall, growth rates roughly increased with SST until they reached the maximum at SST of 21–22°C (i.e. optimal growth temperature), and declined when SST went over 21–22°C. On the contrary, no clear relationship was observed between growth rate and plankton density or between SST and plankton density. Therefore, the apparent among‐region differences would be firstly caused by the differences in regional SST range. The systematic mechanism of growth determination for widespread pelagic fish species larvae would be run by primarily sea temperature and secondarily food availability, at the species level.

Growth rates of Aporrectodea caliginosa (Oligochaetae: Lumbricidae) as influenced by soil temperature and moisture in disturbed and undisturbed soil columns

Summary Earthworm growth is affected by fluctuations in soil temperature and moisture and hence, may be used as an indicator of earthworm activity under field conditions. There is no standard methodology for measuring earthworm growth and results obtained in the laboratory with a variety of food sources, soil quantities and container shapes cannot easily be compared or used to estimate earthworm growth in the field. The objective of this experiment was to determine growth rates of the endogeic earthworm Aporrectodea caliginosa (Savigny) over a range of temperatures (5–20 °C) and soil water potentials (−5 to−54 kPa) in disturbed and undisturbed soil columns in the laboratory. We used PVC cores (6 cm diameter, 15 cm height) containing undisturbed and disturbed soil, and 1 l cylindrical pots (11 cm diameter, 14 cm height) with disturbed soil. All containers contained about 500 g of moist soil. The growth rates of juvenile A. caliginosa were determined after 14–28 days. The instantaneous growth rate (IGR) was affected significantly by soil moisture, temperature, and the temperature×moisture interaction, ranging from −0.092 to 0.037 d −1 . Optimum growth conditions for A. caliginosa were at 20 °C and −5 kPa water potential, and they lost weight when the soil water potential was −54 kPa for all temperatures and also when the temperature was 5 °C for all water potentials. Growth rates were significantly greater in pots than in cores, but the growth rates of earthworms in cores with undisturbed or disturbed soil did not differ significantly. The feeding and burrowing habits of earthworms should be considered when choosing the container for growth experiments in order to improve our ability to extrapolate earthworm growth rates from the laboratory to the field.

Atomic Layer Deposition of Low-Resistivity and High-Density Tungsten Nitride Thin Films Using B[sub 2]H[sub 6], WF[sub 6], and NH[sub 3

Tungsten nitride thin films were grown by atomic layer deposition using alternating exposures of B 2 H 6 , WF 6 , and NH 3 at 300°C. The film thickness linearly increased with the number of the reaction cycles and the determined growth rate was ∼0.28 nm/cycle with B 2 H 6 , WF 6 , and NH 3 at pulsing times of 5, 0.25, and 2 s, respectively. The film had a resisitivity of ∼350 μΩ cm with a metallic W-N bond and density of ∼15 g/cm 3 at the thickness of 10 nm. X-ray diffractometry analysis showed that the film had nanocrystalline grains with β-W 2 N and δ-WN phase. Step coverage was approximately 100% even on the 0.14 μm diameter contact hole with a 16:1 aspect ratio.

Detection of SiH3 radicals and cluster formation in a highly H2 diluted SiH4 VHF plasma by means of time resolved cavity ring down spectroscopy

AbstractThe spatial distribution of the SiH3 radicals between the electrodes of a hydrogen diluted silane VHF plasma under thin film hydrogenated microcrystalline silicon (μc-Si:H) growth conditions has been measured using the time resolved cavity ringdown (τ-CRD) absorption spectroscopy technique. The μc-Si:H growth rate is estimated from the measured spatial SiH3 profiles using a simple model based upon diffusion controlled flux of SiH3 radicals to the electrode surface, where the SiH3 can react with the film surface. The calculated value of μc-Si:H growth rate roughly agrees with the value of the experimentally determined growth rate. This agreement implies that the SiH3 radical is the main growth contributor to the μc-Si:H growth. Furthermore, the τ-CRD reveals the growth kinetics of the clusters in the plasma by light scattering at these clusters on time scales of 1 s after the plasma ignition.

Grain growth in partially molten olivine aggregates

Grain growth rates in partially molten olivine aggregates were determined experimentally at a pressure of 1 GPa. The aim of the experiments with fine-grained starting material (solution–gelation derived Fo90 olivine with a grain size of ∼1 μm with 2 and 4 wt.% added basaltic glass) was to determine growth rates during steady-state grain growth. A series of experiments was conducted at a fixed temperature of 1,350°C for durations from 2 to 700 h, and a second series at fixed duration (168 h) at temperatures from 1,250 to 1,450°C. The resulting activation energy (E=390 kJ/mol) and growth exponent (n=4.3) are comparable to melt-free results (Nichols and Mackwell 1991). The observed grain size distributions are broader than those predicted for normal grain growth or Ostwald ripening and most similar to the Log-normal distribution. The observed melt distribution is influenced by the continuous rearrangement of neighboring grains during growth. The relatively large growth exponent observed in this study and by Nichols and Mackwell (1991) where secondary phases are present suggests that grain growth in the upper mantle is slower than predicted by Karato (1989).

Copper and Zinc Accumulation by a Transplanted Bivalve, Elliptio buckleyi, in Freshwater Systems in Central Florida

ABSTRACT We evaluated the potential use of the native freshwater bivalve, Elliptio buckleyi, as a biomonitor for stormwater metals [i.e., copper (Cu) and zinc (Zn)] in four small water bodies in central Florida. Mussels were collected from a local stream, placed into cages and then deployed into water bodies that received urban drainage of varying quality. Over a 12-month period, mussel growth rates and changes in tissue metal concentrations were compared to the reference site. Growth rate of E. buckleyi was not influenced by water column metal levels; initial mussel size largely determined growth rate. Growth rates were also greater at sites with higher water hardness and chlorophyll a concentrations, suggesting that these parameters may influence growth rates. Metal concentrations in soft-body tissues of transplanted mussels populations increased with increasing water column Zn and Cu concentrations and this relationship was independent of mussel growth rate. Our data demonstrate that E. buckleyi can be an effective biomonitor for these metals in fresh waters.

A simple equation for describing the temperature dependent growth of free-floating macrophytes

Temperature is one of the most important factors determining growth rates of free-floating macrophytes in the field. To analyse and predict temperature dependent growth rates of these pleustophytes, modelling may play an important role. Several equations have been published for describing temperature responses of macrophytes and algae. But they are often complex or are only applicable in a limited range of temperatures. In this paper, we present a simple three-parameter equation for describing the temperature dependent growth rates of pleustophytes. The equation that we developed is tested using results from laboratory growth experiments conducted with three different species of pleustophytes ( Lemna minor, Salvinia molesta and Azolla filiculoides). The equation is simple and demonstrates reliable fits (adjusted R 2 reaching from 0.89 to 0.95). Additionally, our equation primarily uses parameters of biological significance, resulting in estimates of useful cardinal temperatures (minimum and maximum).