A Simulation Model of Lake Trout Growth

1971 ◽  
Vol 28 (6) ◽  
pp. 815-819 ◽  
Author(s):  
S. R. Kerr
Keyword(s):  
Simulation Model ◽  
Growth Model ◽  
Lake Trout ◽  
Growth Efficiency ◽  
Equation System ◽  
Growth Increments ◽  
Predator Size ◽  
Mean Size ◽  
The Mean

Kerr (J. Fish. Res. Bd. Canada 28: 809–814, 1971) described an equation system based upon metabolic constraints and foraging limitations that predicts level of rations and growth efficiency as a function of the availability of the prey resource. An algorithm that extends the equation system to a growth model is described here. With reference to increasing predator size, and to the mean size and abundance of prey, the model computes successive growth increments while holding the equations to the configuration that maximizes the ratio of growth efficiency to rations. When given information on the mean size and density of prey organisms, the model accurately predicts observed patterns of lake trout growth.

Further Analysis of Ration and Growth Relationship of Plaice (Pleuronectes platessa)

1969 ◽  
Vol 26 (12) ◽  
pp. 3237-3241 ◽  
Author(s):  
Samir Zaky Rafail
Keyword(s):  
Maximum Growth ◽  
Growth Efficiency ◽  
Growth Increment ◽  
Mean Value ◽  
Pleuronectes Platessa ◽  
Growth Increments ◽  
Power Equation ◽  
The Mean ◽  
Relationship Of ◽  
Weight Groups

Evidence is given that the average daily rations (R) and fortnightly growth increments (ΔW) of six weight groups of Pleuronectes platessa fed on Mytilus edulis are related as in the power equation ±(ΔW−ΔWm) = ±b(|R–Rm|)B. Rm is the daily ration associated with the growth increment (ΔWm) at maximum growth efficiency; b and B are parameters. The power B has a mean value of about 0.5 and shows significant deviations from the mean especially in the case of smaller fish.

Lake Trout (Salvelinus namaycush) Growth Potential Predicted from Cisco (Coregonus artedii) Population Structure and Conductivity

1989 ◽  
Vol 46 (9) ◽  
pp. 1531-1538 ◽  
Author(s):  
Edward A. Trippel ◽  
F. William H. Beamish
Keyword(s):  
Lake Trout ◽  
Fork Length ◽  
Growth Efficiency ◽  
Salvelinus Namaycush ◽  
Growth Potential ◽  
Food Sources ◽  
Stepwise Multiple Regression ◽  
Order Of Magnitude ◽  
Mean Size ◽  
Coregonus Artedii

Trophic dynamics between lake trout (Salvelinus namaycush) and cisco (Coregonus artedii) were examined in a set of 10 northwestern Ontario lakes that ranged in conductivity by nearly an order of magnitude. Diets revealed the possibility of interspecific competition for invertebrate prey prior to initiation of piscivory by lake trout at approximately 200 mm fork length (FL). Von Bertalanffy growth equations (based on otolith ages) were used to estimate time to attain this length (1.4–3.0 yr). Contrary to anticipated results, lake trout reached this size more rapidly in lakes with high cisco abundance. Presumably, this relationship was caused by improved food conditions for young trout in some of the more productive waterbodies. However, after removing the collinearity between lake conductivity and nonpiscivorous growth by regression analysis, there was no relationship between the time for lake trout to reach 200 mm and cisco abundance. Piscivorous growth varied (L∞ = 508 to 740 mm) extensively among the 10 populations and was likely a function of growth efficiency from different food sources. Using stepwise multiple regression, 81% of the L∞ variation among lakes was explained by cisco abundance and mean size. Linear regression between L∞ and mean size of trout (but not trout abundance) on conductivity generated significant positive relationships.

Dynamics of individual growth in a recovering population of lake trout (Salvelinus namaycush)

2001 ◽  
Vol 58 (2) ◽  
pp. 262-272 ◽  
Author(s):  
Mary C Fabrizio ◽  
Robert M Dorazio ◽  
Stephen T Schram
Keyword(s):  
Growth Rates ◽  
Lake Trout ◽  
Growth Dynamics ◽  
Salvelinus Namaycush ◽  
Wild Fish ◽  
Individual Growth ◽  
Wisconsin Department ◽  
Growth Increments ◽  
Before And After ◽  
The Mean

In 1976, the Wisconsin Department of Natural Resources established a refuge for a nearly depleted population of lake trout (Salvelinus namaycush) at Gull Island Shoal, Lake Superior. The refuge was intended to reduce fishing mortality by protecting adult lake trout. We examined the growth dynamics of these lake trout during the period of recovery by comparing estimates of individual growth before and after the refuge was established. Our estimates are based on an annual mark-recapture survey conducted at the spawning area since 1969. We developed a model that allowed mean growth rates to differ among individuals of different sizes and that accommodated variation in growth rates of individuals of the same size. Likelihood ratio tests were used to determine if the mean growth increments of lake trout changed after the refuge was established. Our results suggest that growth of mature lake trout (particularly wild fish) decreased significantly in the postrefuge period. This decreased growth may have been associated with a reduction in food availability. We also observed reductions in growth as wild fish grew older and larger, which suggests that the growth of these fish may be adequately approximated by a von Bertalanffy growth model if it becomes possible to obtain accurate ages.

Batch Precipitation of Lead Iodide

1994 ◽  
Vol 59 (6) ◽  
pp. 1301-1304
Author(s):  
Jaroslav Nývlt ◽  
Stanislav Žáček
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Crystal Size ◽  
Lead Nitrate ◽  
Lead Iodide ◽  
Constant Rate ◽  
Mean Size ◽  
The Mean

Lead iodide was precipitated by a procedure in which an aqueous solution of potassium iodide at a concentration of 0.03, 0.10 or 0.20 mol l-1 was stirred while an aqueous solution of lead nitrate at one-half concentration was added at a constant rate. The mean size of the PbI2 crystals was determined by evaluating the particle size distribution, which was measured sedimentometrically. The dependence of the mean crystal size on the duration of the experiment exhibited a minimum for any of the concentrations applied. The reason for this is discussed.

scholarly journals Effects of topical gel formulation of Ficus carica latex on cutaneous leishmaniasis induced by Leishmania major in BALB/c mice

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ali Pouryousef ◽  
Erfan Eslami ◽  
Sepehr Shahriarirad ◽  
Sina Zoghi ◽  
Mehdi Emami ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Murine Model ◽  
Leishmania Major ◽  
Considerable Effect ◽  
Ficus Carica ◽  
Control Group ◽  
Topical Gel ◽  
The Third ◽  
Mean Size ◽  
The Mean

Abstract Objectives The current study aimed to evaluate the effects of Ficus carica latex on the treatment of cutaneous leishmaniasis (CL), induced by Leishmania major. A 5% topical gel with F. carica latex was prepared. BALB/c mice were infected by inoculation of amastigotes form of L. major. Thirty BALB/c mice were divided into five groups, where the first group was treated daily, the second group twice per day, and the third group every other day with the 5% topical gel, for 3 weeks. The sizes of the lesions were measured before and during the course of treatment. Results Although the mean size of lesions in the mice group treated with the 5% F. carica gel, especially in the group receiving daily treatment, was less than the mean size of the lesions in the control group, yet, the differences was not statistically significant (p > 0.05). The findings of the current study demonstrated that the 5% F. carica latex with a 3-week course of treatment had no considerable effect in recovery or control of CL induced by L. major in the murine model. Using higher concentration of F. carica latex and with longer treatment lengths may increase its efficacy in the treatment of CL.

scholarly journals Mudrock Microstructure: A Technique for Distinguishing between Deep-Water Fine-Grained Sediments

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 653
Author(s):  
Shereef Bankole ◽  
Dorrik Stow ◽  
Zeinab Smillie ◽  
Jim Buckman ◽  
Helen Lever
Keyword(s):  
Grain Size ◽  
Deep Water ◽  
Sedimentary Facies ◽  
X Ray Diffraction ◽  
Weak Current ◽  
Large Area ◽  
Fine Grained ◽  
Mean Size ◽  
The Mean ◽  
Water Facies

Distinguishing among deep-water sedimentary facies has been a difficult task. This is possibly due to the process continuum in deep water, in which sediments occur in complex associations. The lack of definite sedimentological features among the different facies between hemipelagites and contourites presented a great challenge. In this study, we present detailed mudrock characteristics of the three main deep-water facies based on sedimentological characteristics, laser diffraction granulometry, high-resolution, large area scanning electron microscopy (SEM), and the synchrotron X-ray diffraction technique. Our results show that the deep-water microstructure is mainly process controlled, and that the controlling factor on their grain size is much more complex than previously envisaged. Retarding current velocity, as well as the lower carrying capacity of the current, has an impact on the mean size and sorting for the contourite and turbidite facies, whereas hemipelagite grain size is impacted by the natural heterogeneity of the system caused by bioturbation. Based on the microfabric analysis, there is a disparate pattern observed among the sedimentary facies; turbidites are generally bedding parallel due to strong currents resulting in shear flow, contourites are random to semi-random as they are impacted by a weak current, while hemipelagites are random to oblique since they are impacted by bioturbation.

Late endoscopic evaluation of the ostium size after external dacryocystorhinostomy

2020 ◽  
pp. 112067212097604
Author(s):  
Reem R Al Huthail ◽  
Yasser H Al-Faky
Keyword(s):  
Chart Review ◽  
Retrospective Chart Review ◽  
Tertiary Hospital ◽  
Nasal Endoscope ◽  
Long Term Follow Up ◽  
Mean Size ◽  
External Dacryocystorhinostomy ◽  
The Mean

Objective: To evaluate the effect of chronicity on the size of the ostium after external dacryocystorhinostomy (DCR) with intubation. Methods: Design: A retrospective chart review of patients who underwent external DCR with intubation over 10 years from January 2003 at a tertiary hospital. All patients were recruited and examined with rigid nasal endoscope. Results: A total number of 66 (85 eyes) patients were included. The mean age at the time of evaluation was 53.1 years with gender distribution of 54 females (81.8 %). The mean duration ±SD between the date of surgery and the date of evaluation was 33.2 ± 33.6 (6–118 months). Our study showed an overall anatomical and functional success of 98.8% and 95.3%, respectively. The mean size of the ostium (±SD) was 23.0 (±15.7) mm2 (ranging from 1 to 80.4 mm2). The size of the ostium was not a significant factor for failure ( p = 0.907). No statistically significant correlation was found between the long-term duration after surgery and the size of the ostium ( R: 0.025, p = 0.157). Conclusions: Nasal endoscopy after DCR is valuable in evaluating the ostium with no observed potential correlation between the long-term follow-up after surgery and the size of the ostium.

Lead inclusions in aluminium

1989 ◽  
Vol 157 ◽  
Author(s):  
E. Johnson ◽  
L. Gråbaek ◽  
J. Bohr ◽  
A. Johansen ◽  
L. Sarholt-Kristensen ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Room Temperature ◽  
Noble Gas ◽  
Melting Transition ◽  
X Ray Diffraction ◽  
Free Surfaces ◽  
The Matrix ◽  
Mean Size ◽  
The Mean ◽  
Spontaneous Phase

ABSTRACTIon implantation at room temperature of lead into aluminium leads to spontaneous phase separation and formation of lead precipitates growing topotactically with the matrix. Unlike the highly pressurised (∼ 1–5 GPa) solid inclusions formed after noble gas implantations, the pressure in the lead precipitates is found to be less than 0.12 GPa.Recently we have observed the intriguing result that the lead inclusions in aluminium exhibit both superheating and supercooling [1]. In this paper we review and elaborate on these results. Small implantation-induced lead precipitates embedded in an aluminium matrix were studied by X-ray diffraction. The (111) Bragg peak originating from the lead crystals was followed during several temperature cycles, from room temperature to 678 K. The melting temperature for bulk lead is 601 K. In the first heating cycle we found a superheating of the lead precipitates of 67 K before melting occurred. During subsequent cooling a supercooling of 21 K below the solidification point of bulk lead was observed. In the subsequent heating cycles this hysteresis at the melting transition was reproducible. The full width of the hysteresis loop slowly decreased to 62 K, while the mean size of the inclusions gradually increased from 14.5 nm to 27 nm. The phenomena of superheating and supercooling are thus most pronounced for the small crystallites. The persistence of the hysteresis loop over successive heating cycles demonstrate that its cause is intrinsic in nature, and it is believed that the superheating originates from the lack of free surfaces of the lead inclusions.

scholarly journals Mechanical ventilation-induced alterations of intracellular surfactant pool and blood–gas barrier in healthy and pre-injured lungs

2020 ◽  
Author(s):  
Jeanne-Marie Krischer ◽  
Karolin Albert ◽  
Alexander Pfaffenroth ◽  
Elena Lopez-Rodriguez ◽  
Clemens Ruppert ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Blood Gas ◽  
Control Groups ◽  
Gas Barrier ◽  
Alveolar Epithelial ◽  
Alveolar Surfactant ◽  
Healthy Control ◽  
Mean Size ◽  
The Mean ◽  
Injury Progression

AbstractMechanical ventilation triggers the manifestation of lung injury and pre-injured lungs are more susceptible. Ventilation-induced abnormalities of alveolar surfactant are involved in injury progression. The effects of mechanical ventilation on the surfactant system might be different in healthy compared to pre-injured lungs. In the present study, we investigated the effects of different positive end-expiratory pressure (PEEP) ventilations on the structure of the blood–gas barrier, the ultrastructure of alveolar epithelial type II (AE2) cells and the intracellular surfactant pool (= lamellar bodies, LB). Rats were randomized into bleomycin-pre-injured or healthy control groups. One day later, rats were either not ventilated, or ventilated with PEEP = 1 or 5 cmH2O and a tidal volume of 10 ml/kg bodyweight for 3 h. Left lungs were subjected to design-based stereology, right lungs to measurements of surfactant proteins (SP−) B and C expression. In pre-injured lungs without ventilation, the expression of SP-C was reduced by bleomycin; while, there were fewer and larger LB compared to healthy lungs. PEEP = 1 cmH2O ventilation of bleomycin-injured lungs was linked with the thickest blood–gas barrier due to increased septal interstitial volumes. In healthy lungs, increasing PEEP levels reduced mean AE2 cell size and volume of LB per AE2 cell; while in pre-injured lungs, volumes of AE2 cells and LB per cell remained stable across PEEPs. Instead, in pre-injured lungs, increasing PEEP levels increased the number and decreased the mean size of LB. In conclusion, mechanical ventilation-induced alterations in LB ultrastructure differ between healthy and pre-injured lungs. PEEP = 1 cmH2O but not PEEP = 5 cmH2O ventilation aggravated septal interstitial abnormalities after bleomycin challenge.

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