Thus, heavily fertilized nursery ponds may experience fish mortality from high concentrations of ammonia and nitrite. In addition, well water used to supply hatcheries and nursery tank systems often ...contains ammonia and nitrite, which may adversely affect the hatching success of eggs and survival of larvae prior to stocking. Toxicity tests have been done on original cross hybrids Morone saxatilis x M. chrysops and striped bass Morone saxatilis fingerlings (Oppenborn and Goudie 1993), but no information is available on the toxicity of ammonia and nitrite to reciprocal cross HSB eggs and larvae. Tolerance to toxins varies between species and among different life stages within each species. Thus, information on the toxicity of ammonia and nitrite to reciprocal cross HSB eggs and larvae would be useful to hatchery managers and fingerling producers to establish acceptable water quality parameters for the hatchery and nursery ponds.
Egg hatch, larval growth, and metamorphosis of southern flounder, Paralichthys lethostigma, were examined at 13, 17, 21, and 25°C in laboratory experiments. The experiments were separated into four ...developmental phases: (1) from fertilization until hatch; (2) from hatch until mouth opening; (3) from first feeding until the onset of metamorphosis; (4) from the onset until the completion of metamorphosis. Time to egg hatch were 109, 58, 39, 30 hours at 13, 17, 21, and 25°C, respectively. Size at hatch varied little among temperatures, while percent hatch was significantly higher at 17°C (P < 0.05). There was no significant difference in total length at mouth opening among temperatures (P > 0.05). However, those larvae raised at higher temperatures reached mouth opening earlier, as it took on average 7.4, 3.9, 2.8, and 2.2 days from hatch at 13, 17, 21, and 25°C, respectively. During phase three, the growth rate was optimal at 17°C, as growth rates were 0.046, 0.110, 0.106 and 0.096 mm/day at 13, 17, 21, and 25°C, respectively. Larvae in phase four completed metamorphosis sooner at higher temperatures than at lower temperatures. It took 26.4, 15.7, and 13.1 days to complete metamorphosis at 17, 21, and 25°C, respectively, while only 16% of those at 13 progressed to stage "G" within the 27 days that phase four encompassed. No difference in total length was found among treatments (P > 0.05) at the completion of metamorphosis, but fish in the 21 °C treatment had a significantly higher survival (P < 0.05). It can be concluded that southern flounder could be produced in the highest quantity and at the largest size by raising them at 17°C from fertilization until the onset of metamorphosis, and at 21 °C during metamorphosis.
Compact, tunable, radially symmetric focusing of electrons is critical to laser-plasma accelerator (LPA) applications. Experiments are presented demonstrating the use of a discharge-capillary active ...plasma lens to focus 100-MeV-level LPA beams. The lens can provide tunable field gradients in excess of 3000 T/m, enabling cm-scale focal lengths for GeV-level beam energies and allowing LPA-based electron beams and light sources to maintain their compact footprint. For a range of lens strengths, excellent agreement with simulation was obtained.
Guiding of relativistically intense laser pulses with peak power of 0.85 PW over 15 diffraction lengths was demonstrated by increasing the focusing strength of a capillary discharge waveguide using ...laser inverse bremsstrahlung heating. This allowed for the production of electron beams with quasimonoenergetic peaks up to 7.8 GeV, double the energy that was previously demonstrated. Charge was 5 pC at 7.8 GeV and up to 62 pC in 6 GeV peaks, and typical beam divergence was 0.2 mrad.
Alternative bait products for the harvesting of blue crabs are needed because traditional baits are becoming increasingly expensive and more difficult to acquire. Poultry mortality carcasses and ...poultry mortality silage were compared to menhaden for their ability to attract blue crabs using on-shore attractant trays as well as off-shore crabpot protocols. When product stability in water was eliminated as a variable in a preliminary investigation, there was no significant difference (P > .10) in the total number of blue crabs harvested using the alternative poultry silage baits versus a menhaden bait control. Attractant tray evaluations indicated an increased preference (P < .035) of female crabs versus male crabs for the alternative poultry baits relative to a menhaden control but failed to demonstrate any significant differences (P > .152) in the preferences of blue crabs for the pH, binder, betaine addition, or poultry meat form used in the alternative bait formulations. In contrast, a marine evaluation of the alternative bait treatments indicated an increased preference (P < .005) for poultry bait products containing no supplemental betaine and a decreased preference (P < .045) for poultry baits adjusted to a pH = 8. A consumer sensory evaluation of the crabmeat harvested from crabs with the alternative baits demonstrated that no off flavors are associated with the use of the alternative poultry baits. Properly formulated, poultry mortality could be utilized as alternative bait for the harvesting of blue crabs and has potential for use as bait for other aquatic species.
Ferroptosis is a non-apoptotic form of regulated cell death caused by the failure of the glutathione-dependent lipid-peroxide-scavenging network. FINO2 is an endoperoxide-containing 1,2-dioxolane ...that can initiate ferroptosis selectively in engineered cancer cells. We investigated the mechanism and structural features necessary for ferroptosis initiation by FINO2. We found that FINO2 requires both an endoperoxide moiety and a nearby hydroxyl head group to initiate ferroptosis. In contrast to previously described ferroptosis inducers, FINO2 does not inhibit system xc– or directly target the reducing enzyme GPX4, as do erastin and RSL3, respectively, nor does it deplete GPX4 protein, as does FIN56. Instead, FINO2 both indirectly inhibits GPX4 enzymatic function and directly oxidizes iron, ultimately causing widespread lipid peroxidation. These findings suggest that endoperoxides such as FINO2 can initiate a multipronged mechanism of ferroptosis.
Abstract
We report results from continued timing observations of PSR J0740+6620, a high-mass, 2.8 ms radio pulsar in orbit with a likely ultracool white dwarf companion. Our data set consists of ...combined pulse arrival-time measurements made with the 100 m Green Bank Telescope and the Canadian Hydrogen Intensity Mapping Experiment telescope. We explore the significance of timing-based phenomena arising from general relativistic dynamics and variations in pulse dispersion. When using various statistical methods, we find that combining ∼1.5 yr of additional, high-cadence timing data with previous measurements confirms and improves on previous estimates of relativistic effects within the PSR J0740+6620 system, with the pulsar mass
m
p
=
2.08
−
0.07
+
0.07
M
⊙
(68.3% credibility) determined by the relativistic Shapiro time delay. For the first time, we measure secular variation in the orbital period and argue that this effect arises from apparent acceleration due to significant transverse motion. After incorporating contributions from Galactic differential rotation and off-plane acceleration in the Galactic potential, we obtain a model-dependent distance of
d
=
1.14
−
0.15
+
0.17
kpc (68.3% credibility). This improved distance confirms the ultracool nature of the white dwarf companion determined from recent optical observations. We discuss the prospects for future observations with next-generation facilities, which will likely improve the precision on
m
p
for J0740+6620 by an order of magnitude within the next few years.
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