Long-term exposure to a synthetic estrogen at levels below those currently found in the environment may have a major impact on fish populations, according to a study accepted today for publication in the December issue of the peer-reviewed journal Environmental Health Perspectives (EHP). The study shows that ethynylestradiol, a potent form of estrogen used in oral contraceptives, can produce sexually compromised males.
Researchers exposed zebrafish to low concentrations of the hormone over three generations and measured the effects. After 210 days, or a full zebrafish lifetime of exposure to ethynylestradiol, second-generation fish showed reduced fertility. In addition, out of nearly 12,000 eggs spawned, none were viable. Upon examination, researchers found that none of the second-generation male fish had normal testes, and they did not produce expressible semen. However, the fish showed normal reproductive behavior patterns, including competing with healthy males.
This research suggests that the development of the testes is more sensitive to disruption by ethynylestradiol than is reproductive behavior. This could have significant population-level consequences, as infertile males have a significant ability to interfere with breeding dynamics. “Previous studies in fish have shown that endocrine disruptors can reduce sperm counts and induce female-specific proteins in males,” said Dr. Jim Burkhart, science editor for EHP. “But until now little evidence existed to show that environmentally relevant concentrations of endocrine disruptors could induce such changes and actually reduce fertility.”
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The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
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15.11.2017 | Event News
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17.11.2017 | Studies and Analyses