Radio telescopes have an advantage over optical telescopes, in that radio telescope can be used even in cloudy conditions here on Earth. That’s because the longer wavelengths of radio waves can pass through clouds unhindered. However, some wavelengths are still partially obscured by portions of Earth’s atmosphere, especially by the ionosphere which traps human-made Radio Frequency Interference (RFI).
Astronomers have developed a new calibration technique that allows them to take sharp images in low radio frequencies — between 16 and 30 MHz — for the first time, bypassing the influence of the ionosphere. The astronomers say this will allow them to study things like plasmas emanating from ancient black holes and perhaps even detect exoplanets that orbit small stars.
The technique was developed by an international team of researchers led by astronomers from Leiden University in the Netherlands.
“It’s like putting on a pair of glasses for the first time and no longer seeing blurred,” said Christian Groeneveld from Leiden University, who led the research.
The LOFAR central stations on a specially engineered field (“superterp”) between Exloo and Buinen in Drenthe, in the north east of the Netherlands. Image: Aerophoto Eelde.The astronomers used the LOFAR telescope in Drenthe, the Netherlands, which is currently one of the best low-frequency radio telescopes in the world. They modified a calibration technique that has been used to improve observations for observing in radio at higher frequencies, around 150 MHz.
“We hoped that we could also extend this technique to lower frequencies, below 30 MHz,” said, Reinout van Weeren, also from Leiden University, who came up with the idea. “And we succeeded.”
To test their technique, they studied several galaxy clusters that had previously only been studied in detail at higher frequencies.
“Our observing strategy consisted of simultaneously observing a bright primary calibrator and the target fields,” the team wrote in their paper. “By scheduling the observation after midnight, we minimized RFI caused by the internal reflection of terrestrial RFI by the ionosphere, which is significantly worse during the day, as ionizing radiation from the Sun increases the column density of ions in the ionosphere.”
Then, they split up their field of view into several smaller “facets” and self-calibrated each facet individually, against the calibrator object. “This yields an improved image and model of the sky, partly corrected for direction dependent effects,” they wrote. They then repeated the calibrations three more times.
Left shows an image of a piece of sky observed with the hitherto best calibration technique. Right shows the same piece of sky with the new technique. More detail is visible, and what were once large, blurry patches now appear as single points. (c) LOFAR/Groeneveld et al.This was the first time radio images at frequencies between 16 and 30 MHz have been taken. Because of this data, the astronomers said that the radio emissions from these clusters is not evenly distributed across the entire cluster, but rather there is a spot pattern.
According to the researchers, the new calibration technique makes it possible to study radio phenomena in frequencies that were previously hidden.
“There is, of course, a chance that we will eventually discover something unexpected,” said Groeneveld.
Read the press release from Astronomy Netherlands
Read the team’s paper
The post Astronomers Have a New Way to Bypass Earth's Atmosphere appeared first on Universe Today.
Among all scientific or medical journals, The Lancet is the most woke, and I’ve written about it several times before, once calling it the “medical Scientific American“. For a fuller account of its wokeness, which seems to be entirely the doing of editor Richard Horton, see this piece from the site The Daily Skeptic, which summarizes a lot of craziness in the journal. The latest mishigass is the long (11-page set of “author guidelines” that you can read by clicking on the link below:
And right near the beginning, on page 2, you read the guidelines for using the terms “sex and gender”. The bolding of the headers is theirs (I’ve put these in caps), but I’ve taken the liberty of putting in bold several select sections of the text.
REPORTING SEX-BASED AND GENDER-BASED ANALYSES
Reporting guidance
For research involving or pertaining to humans, animals, model organisms, or eukaryotic cells, investigators should integrate sex-based and gender-based analyses into their research design according to evolving funder/sponsor requirements and best practices within a field. Authors should address their research’s sex and/or gender dimensions in their manuscript. In cases where they cannot, they should discuss this as a limitation to their research’s generalisability. With research involving cells and model organisms, researchers should use the term “sex”. With research involving humans, researchers should consider which terms best describe their data (see Definitions section below). Authors can refer to the Sex and Gender Equity in Research (SAGER) Guidelines and the SAGER guidelines checklist. They offer systematic approaches to the use and editorial review of sex and gender information in study design, data analysis, outcome reporting, and research interpretation. However, there is no single, universally agreed-upon set of guidelines for defining sex and gender or reporting sex-based and gender-based analyses.
DEFINITIONS
In human research, the term “sex” carries multiple definitions. It often refers to an umbrella term for a set of biological attributes associated with physical and physiological features (eg, chromosomal genotype, hormonal levels, internal and external anatomy). It can also signify a sex categorisation, most often designated at birth (“sex assigned at birth”) based on a newborn’s visible external anatomy. The term “gender” generally refers to socially constructed roles, behaviours, and identities of women, men, and gender-diverse people that occur in a historical and cultural context, and might vary across societies and over time. Gender influences how people view themselves and each other, how they behave and interact, and how power is distributed in society. Sex and gender are often incorrectly portrayed as binary (female/male or woman/man), concordant, and static. However, these constructs exist along a spectrum that includes additional sex categorisations and gender identities, such as people who are intersex/have differences of sex development (DSD), or identify as non-binary. In any given person, sex and gender might not align, and both can change. Sex and gender are not entirely discrete concepts and their definitions continue to evolve. Biology and society influence both, and many languages do not distinguish between them. Since the terms “sex” and “gender” can be ambiguous, authors should describe the methods they use to gather and report sex-related and/or gender-related data (eg, self-report or physician-report, specific biological attributes, current sex/gender, sex assigned at birth, etc) and discuss the potential limitations of those methods. This will enhance the research’s precision, rigor, and reproducibility, and avoid ambiguity or conflation of terms and the constructs to which they refer. Authors should use the term “sex assigned at birth” rather than “biological sex”, “birth sex” or “natal sex” as it is more accurate and inclusive. When ascertaining gender and sex, researchers should use a two-step process: (1) ask for gender identity allowing for multiple options and (2) if relevant to the research question, ask for sex assigned at birth. In addition to this defining guidance and the SAGER guidelines, you can find further information about reporting sex and gender in research studies on Elsevier’s diversity, equity, and inclusion in the publishing author guide available here.
Note that everything referred to here deals with HUMANS, as this is a medical journal. Note that the editors specify that “sex” has multiple definitions, but in so doing mix up the way sex is determined in humans (chromosomes carrying sex-determining genes), the way it is observed at birth (usually via genitalia), and the way it is defined (whether an individual has the apparatus for producing big, immobile gametes (“females”) or small, mobile gametes (“males”).
Biologists agree about the gametic definition of sex, which produces the sex binary that I’ve discussed so often, and that definition is not ambiguous. (Note that there are no cases of hermaphrodites in humans that are functional as both males and females, so even if you considere hermaphrodites to be members of a “third sex”, and I don’t, they don’t exist in our species.)
The editors also state twice that sex is “not static” and can change, but biological sex cannot change. What can change is gender—unless you use a hormonally-based definition of sex, which is not tenable and was used only to determine which group someone could compete in athletically. (The Olympics has now abandoned that approach.)
Finally, note that The Lancet recommends the term “sex assigned at birth,” which is simply wrong. Sex is not ASSIGNED at birth, it is observed at birth, but observed using characters like genitalia that are almost always concordant with biological sex but may not be infallible indicators of biological sex. But regardless, sex is never “assigned” but exists. The exceptions to the sex binary—individuals who are truly intersex—comprise about 0.018% of people, or about 1 in 5600. As I always say, “that’s as close to binary as you can come.”
Finally, why do the editorial guidelines imply that sex is not “static”? There is only one reason I can think of, and that’s trying to push on the journal’s readers a gender-activist ideology. If you truly believe that a transwoman is a woman in terms of biological sex, or a transman is a man in terms of biological sex, then yes, you can say that sex is malleable. But this is not accurate, for using the biological definitions of sex, a transwoman remains a biological man and a transman remains a biological women. (This of course is not to demean them or say that they’re somehow morally unequal to the rest of us; it’s just biology.) In the end, biological sex is not malleable but static.
As the Daily Skeptic notes at the end of its piece:
The Lancet’s guidelines on sex conclude by explicitly telling authors to use the term “sex assigned at birth” because it is “more accurate and inclusive”. I’m imagining a future Lancet article on Elizabeth Garrett Anderson: “She was the first person who’d been assigned ‘female’ at birth to qualify as a doctor in Britain, and she went on to found the first medical school to train people who’d been assigned ‘female’ at birth. All in all, she was a truly remarkable person who’d been assigned ‘female’ at birth.”
If this were some obscure Gender Studies periodical, it wouldn’t really matter. But we’re talking about the world’s second most cited medical journal. It’s read by doctors, surgeons, researchers and all the people to whom we’ve entrusted our health. How can they maintain our trust when they can’t seem to tell the difference between a man and a woman?
Indeed!
h/t: Luana