Why does egg size of salmonids increase with the mean size of population spawning gravels?

2011 ◽  
Vol 68 (8) ◽  
pp. 1307-1315 ◽  
Author(s):  
Njal Rollinson ◽  
Jeffrey A. Hutchings
Keyword(s):  
Egg Size ◽  
Oxygen Limitation ◽  
Yolk Sac ◽  
Growth And Survival ◽  
Complete Development ◽  
Gravel Size ◽  
Mean Size ◽  
The Mean ◽  
Compaction Stress ◽  
Offspring Investment

Population mean egg size of salmonids increases with the mean size of gravels in which a population spawns. A long-standing hypothesis is that large larvae cannot navigate small-gravel interstices, so mothers must decrease per-offspring investment when spawning gravels are small. We manipulated the size of incubation gravels and egg size of Atlantic salmon (Salmo salar) to test whether size-related entombment of larvae occurs. We find little evidence of size-related entombment, but we find evidence that gravel size does not affect all larval sizes equally. Larger larvae emerge from small gravels before development is complete and with a visible yolk sac, possibly due to oxygen limitation in small gravels. Smaller larvae always complete development in the gravel and emerge without a yolk sac. Although growth and survival may increase with juvenile size following yolk-sac absorption, juveniles with yolk sacs may fare worse when depredation rates are high. The egg size – gravel size correlation may therefore reflect increased postemergence mortality among larger offspring in small-gravel environments. Alternatively, compaction stress in fine gravels coupled with size asymmetries in larval strength may have caused the patterns that we observed, in which case our data may not help explain the egg size – gravel size correlation.

Influence of Egg Characteristics on Survival, Growth and Feeding in Larval Walleye (Stizostedion vitreum)

1989 ◽  
Vol 46 (3) ◽  
pp. 516-521 ◽  
Author(s):  
G. E. E. Moodie ◽  
N. L. Loadman ◽  
M. D. Wiegand ◽  
J. A. Mathias
Keyword(s):  
Fatty Acids ◽  
Mortality Rate ◽  
Growth Rates ◽  
Egg Size ◽  
The Other ◽  
Stizostedion Vitreum ◽  
Mean Size ◽  
Survival And Growth ◽  
The Mean ◽  
High Level

A subsample of eggs from 109 walleye (Stizostedion vitreum) from Crean Lake, Saskatchewan, was sieved soon after fertilization to yield four groups of eggs ranging in size from 4.86 to 5.62 mm3. Overall egg size tended to correspond to yolk and oil volumes. At hatching, larvae from the eggs with the least yolk and oil were significantly shorter than larvae from all other egg groups. At the end of the experiment, 13 d after hatching, the larvae from the eggs with the most yolk were significantly larger than larvae from the other egg groups. Differences in the mean amount of food ingested by larvae were related to initial egg size. The yolk of the smallest eggs was deficient in the (n-3) series of polyunsaturated fatty acids. Larvae from these small eggs had a high level of major body deformities and a mortality rate which reached 100% by day 10. Small egg size in itself did not appear disadvantageous; larvae from a different stock (Lake of the Prairies, Manitoba) which produced eggs with a mean size less than that of the smallest sieved eggs, had survival and growth rates comparable with those of the larger Crean Lake eggs.

scholarly journals Sphaeridiotrema globulus (Rudolphi, 1814) (Digenea): evidence for two species known under a single name and a description of Sphaeridiotrema pseudoglobulus n.sp.

1993 ◽  
Vol 71 (4) ◽  
pp. 700-707 ◽  
Author(s):  
J. Daniel McLaughlin ◽  
Marilyn E. Scott ◽  
Jane E. Huffman
Keyword(s):  
New Jersey ◽  
Egg Size ◽  
Anterior Testis ◽  
The Body ◽  
Internal Organs ◽  
Posterior Testis ◽  
Mean Size ◽  
Basal Bulb ◽  
The Mean ◽  
A New Species

Experimental infection of domestic ducklings with metacercariae believed to be those of Sphaeridiotrema globulus from snails in Quebec, Canada, and New Jersey, U.S.A., revealed that there are two species known under this name. Study of museum specimens has confirmed that the New Jersey specimens represent the original S. globulus: the specimens from Quebec represent a new species. The two species can be separated reliably on the basis of egg size: S. globulus (New Jersey) has smaller eggs (mean 97 ± 4 (SD) μm; range 91–108 μm) than S. pseudoglobulus n.sp. from Quebec (mean 116 ± 5 μm: range 103–125 μm). The cirrus in S. pseudoglobulus has a basal bulb not found in that of S. globulus. There are fewer uterine coils anterior to the acetabulum in S. pseudoglobulus. Comparison of 6-day-old populations of each species revealed several statistically significant differences in the mean size of internal organs. The overall sizes of the body, ovary, and eggs and the width of the posterior testis were greater in S. pseudoglobulus: the pharynx, length of the posterior testis, and number of eggs in the uterus were greater in S. globulus. No differences were found in the size of the oral sucker, acetabulum, or anterior testis.

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.

scholarly journals Egg size-dependent expression of growth hormone receptor accompanies compensatory growth in fish

2011 ◽  
Vol 279 (1728) ◽  
pp. 592-600 ◽  
Author(s):  
F. H. I. D. Segers ◽  
G. Berishvili ◽  
B. Taborsky
Keyword(s):  
Growth Hormone ◽  
Hormone Receptor ◽  
Egg Size ◽  
Growth Hormone Receptor ◽  
Yolk Sac ◽  
Juvenile Growth ◽  
Somatotropic Axis ◽  
Expression Levels ◽  
Potential Link ◽  
Adaptive Adjustment

Large egg size usually boosts offspring survival, but mothers have to trade off egg size against egg number. Therefore, females often produce smaller eggs when environmental conditions for offspring are favourable, which is subsequently compensated for by accelerated juvenile growth. How this rapid growth is modulated on a molecular level is still unclear. As the somatotropic axis is a key regulator of early growth in vertebrates, we investigated the effect of egg size on three key genes belonging to this axis, at different ontogenetic stages in a mouthbrooding cichlid ( Simochromis pleurospilus ). The expression levels of one of them, the growth hormone receptor ( GHR ), were significantly higher in large than in small eggs, but remarkably, this pattern was reversed after hatching: young originating from small eggs had significantly higher GHR expression levels as yolk sac larvae and as juveniles. GHR expression in yolk sac larvae was positively correlated with juvenile growth rate and correspondingly fish originating from small eggs grew faster. This enabled them to catch up fully in size within eight weeks with conspecifics from larger eggs. This is the first evidence for a potential link between egg size, an important maternal effect, and offspring gene expression, which mediates an adaptive adjustment in a relevant hormonal axis.

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.

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