Sexual maturation versus immaturity: different tactics with adaptive values in Baltic salmon (Salmo salar L.) male smolts

1982 ◽  
Vol 60 (8) ◽  
pp. 1822-1827 ◽  
Author(s):  
Hans Lundqvist ◽  
Gunnar Fridberg
Keyword(s):  
Growth Rate ◽  
Salmo Salar ◽  
Sexual Maturation ◽  
Brackish Water ◽  
High Growth ◽  
High Growth Rate ◽  
Alternative Tactics ◽  
Endogenous Rhythms ◽  
Neuroendocrine Axis ◽  
The Baltic

Precocious 2-year-old male parr of the Baltic salmon (Salmo salar L.) were retained in freshwater or exposed to brackish water (4.6–5‰) in net pens after smoltification. Comparisons of growth rates and the incidence of sexual maturation revealed great differences between the two groups. In the freshwater group, the growth rate was retarded from mid-July and the fish acquired parr markings. In autumn, they all matured. The group in brackish water became rapidly growing, immature postsmolts. Only 7% matured in the autumn. The increase in mean weight of the postsmolts was 500% from the start of the experiment compared with 90% for the fish retained in freshwater.It is hypothesized that these alternative tactics expressed by salmon male smolts, i.e., sexual maturation combined with a low growth rate while in freshwater compared with sexual immaturity and a high growth rate while in sea, are mutually exclusive. Furthermore, it is suggested that these processes are controlled by annual endogenous rhythms (circannual rhythms) in interaction with the environment–neuroendocrine axis.

Effects of size and spring growth on sexual maturation in 1+ Atlantic salmon (Salmo salar) male parr: interactions with smoltification

1995 ◽  
Vol 52 (12) ◽  
pp. 2682-2694 ◽  
Author(s):  
Ingemar Berglund
Keyword(s):  
Growth Rate ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Sexual Maturation ◽  
Food Restriction ◽  
High Growth ◽  
High Growth Rate ◽  
Early Summer ◽  
Fish Length ◽  
Atlantic Salmon Salmo Salar

Individually identified 1-year-old Atlantic salmon (Salmo salar) parr of Baltic origin were subjected to four different restricted feeding regimes during May and June, and the effects of feeding regime and fish length on the probability of sexual maturation in males were evaluated using logistic regression. Food restriction in June decreased specific growth in weight during June to ca. 22% of that in the control. On average, the maturation rate was reduced from 60% in controls to 48, 45, and 36% in groups on restricted rations. Furthermore, the positive effect of initial length on the probability of maturation was depressed in groups on restricted food in June or May and June. The results of this study show that food restriction in spring has a significant negative effect on the probability of maturation in male salmon parr, but maturation seems to be suppressed in only a small part of the experimental populations. The occurrence of maturing males among fish with a very low or negative growth rate during June and poor condition by the end of June implies, however, that high growth rate in June is not necessary for the onset of rapid gonadal growth in early summer.

Exploring SiC Growth Limitation of Vapor-Liquid-Solid Mechanism when Using Two Different Carbon Precursors

2013 ◽  
Vol 740-742 ◽  
pp. 323-326
Author(s):  
Kassem Alassaad ◽  
François Cauwet ◽  
Davy Carole ◽  
Véronique Soulière ◽  
Gabriel Ferro
Keyword(s):  
Growth Rate ◽  
High Growth ◽  
High Growth Rate ◽  
Carbon Precursor ◽  
Growth Limitation ◽  
Vapor Liquid Solid ◽  
Partial Pressures ◽  
Vapor Liquid Solid Mechanism ◽  
Vls Growth ◽  
Vapor Liquid

Abstract. In this paper, conditions for obtaining high growth rate during epitaxial growth of SiC by vapor-liquid-solid mechanism are investigated. The alloys studied were Ge-Si, Al-Si and Al-Ge-Si with various compositions. Temperature was varied between 1100 and 1300°C and the carbon precursor was either propane or methane. The variation of layers thickness was studied at low and high precursor partial pressure. It was found that growth rates obtained with both methane and propane are rather similar at low precursor partial pressures. However, when using Ge based melts, the use of high propane flux leads to the formation of a SiC crust on top of the liquid, which limits the growth by VLS. But when methane is used, even at extremely high flux (up to 100 sccm), no crust could be detected on top of the liquid while the deposit thickness was still rather small (between 1.12 μm and 1.30 μm). When using Al-Si alloys, no crust was also observed under 100 sccm methane but the thickness was as high as 11.5 µm after 30 min growth. It is proposed that the upper limitation of VLS growth rate depends mainly on C solubility of the liquid phase.

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.

Emission characteristics of GaInN/GaN multiple quantum shell nanowire-based LEDs with different p-GaN growth conditions

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sae Katsuro ◽  
Weifang Lu ◽  
Kazuma Ito ◽  
Nanami Nakayama ◽  
Naoki Sone ◽  
...  
Keyword(s):  
Growth Rate ◽  
Shell Growth ◽  
Light Output ◽  
High Growth ◽  
Growth Conditions ◽  
High Growth Rate ◽  
Current Injection ◽  
Emission Characteristics ◽  
Multiple Quantum ◽  
Plane Region

Abstract Improving current injection into r- and m-planes of nanowires (NWs) is essential to realizing efficient GaInN/GaN multiple quantum shell (MQS) NW-based light-emitting diodes (LEDs). Here, we present the effects of different p-GaN shell growth conditions on the emission characteristics of MQS NW-LEDs. Firstly, a comparison between cathodoluminescence (CL) and electroluminescence (EL) spectra indicates that the emission in NW-LEDs originates from the top region of the NWs. By growing thick p-GaN shells, the variable emission peak at around 600 nm and degradation of the light output of the NW-LEDs are elaborated, which is attributable to the localization of current in the c-plane region with various In-rich clusters and deep-level defects. Utilizing a high growth rate of p-GaN shell, an increased r-plane and a reduced c-plane region promote the deposition of indium tin oxide layer over the entire NW. Therefore, the current is effectively injected into both the r- and m-planes of the NW structures. Consequently, the light output and EL peak intensity of the NW-LEDs are enhanced by factors of 4.3 and 13.8, respectively, under an injection current of 100 mA. Furthermore, scanning transmission electron microscope images demonstrate the suppression of dislocations, triangular defects, and stacking faults at the apex of the p-GaN shell with a high growth rate. Therefore, localization of current injection in nonradiative recombination centers near the c-plane was also inhibited. Our results emphasize the possibility of realizing high efficacy in NW-LEDs via optimal p-GaN shell growth conditions, which is quite promising for application in the long-wavelength region.

High growth-rate atomic layer deposition process of cerium oxide thin film for solid oxide fuel cell

2019 ◽  
Vol 45 (3) ◽  
pp. 3811-3815 ◽  
Author(s):  
Jin-Geun Yu ◽  
Byung Chan Yang ◽  
Jeong Woo Shin ◽  
Sungje Lee ◽  
Seongkook Oh ◽  
...  
Keyword(s):  
Thin Film ◽  
Growth Rate ◽  
High Growth ◽  
Atomic Layer ◽  
Deposition Process ◽  
High Growth Rate ◽  
Solid Oxide ◽  
Oxide Thin Film ◽  
Oxide Fuel ◽  
Layer Deposition
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