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Hip implants with a delta ceramic or oxidized zirconium head and highly crosslinked polyethylene liner or cup had the lowest risk of revision during the 15 years after surgery, a new study has found. The research could help hospitals, surgeons and patients to choose what hip implant to use for replacement surgery.

The brain pathway that causes hairy mammals like mice and dogs to shake themselves dry appears to have more to do with pressure than temperature

Oil and water can be separated efficiently by pumping the mixture through thin channels between two semipermeable membranes

If I ask you to picture a radio telescope, you probably imagine a large dish pointing to the sky, or even an array of dish antennas such as the Very Large Array. What you likely don’t imagine is something that resembles a TV dish in your neighbor’s backyard. With modern electronics, it is relatively easy to build your own radio telescope. To understand out how it can be done, check out a recent paper by Jack Phelps.

He outlines in detail how you can construct a small radio telescope with a 1-meter satellite dish, a Raspberry Pi, and some other basic electronics such as analog-to-digital converters. It’s a fascinating read, and one of the most interesting features is that his design is tuned to a frequency of 1420.405 MHz. This is the frequency emitted by neutral hydrogen. Since it has a wavelength of about 21 centimeters, the hydrogen emission line is sometimes called the 21-cm line. Neutral hydrogen comprises the bulk of matter in the Universe. The 21-cm emission isn’t particularly bright, but because there is so much hydrogen out there, the signal is easy to detect. And wherever there is matter, so too is the hydrogen line.

Observations of hydrogen in the Milky Way (red dots). Credit: Jack Phelps

The emission is caused by a spin flip of the hydrogen’s electron. It’s a hyperfine emission, which means the line is very sharp. If you see the line shifted a bit, you know that’s because of relative motion. Astronomers have used the line to map the distribution of matter in the Milky Way, and have even used it to measure our galaxy’s rotation. Early observations of the line pointed to the existence of dark matter in our galaxy. And now you can do it at home.

There are other radio objects you can observe in the sky. The Sun is a popular target given its strong radio signal. Jupiter is another somewhat bright source. It’s a cool hobby. Even if you don’t intend to build a radio telescope of you’re own, it’s worth checking out the paper just to see how accessible radio astronomy has become.

Reference: J. Phelps. “Galactic Neutral Hydrogen Structures Spectroscopy and Kinematics: Designing a Home Radio Telescope for 21 cm Emission.” arXiv preprint arXiv:2411.00057 (2024).

The post You Can Build a Home Radio Telescope to Detect Clouds of Hydrogen in the Milky Way appeared first on Universe Today.

Blood tests have shown that about 7 per cent of workers on dairy farms that had H5N1 outbreaks had antibodies against the disease

When it comes to the survival of animals living in the wild, the characteristics of the group can matter as much as the traits of the individual, according to a study in marmots

A team has developed a plastic surgical field expansion plate that can help surgeons during robot-assisted heart surgery.

A team has developed a plastic surgical field expansion plate that can help surgeons during robot-assisted heart surgery.

Readily available thermoelectric generators operating under modest temperature differences can power CO2 conversion, according to a proof-of-concept study by chemists. The findings open up the intriguing possibility that the temperature differentials encountered in an array of environments -- from a typical geothermal installation on Earth to the cold, desolate surface of Mars -- could power the conversion of CO2 into a range of useful fuels and chemicals.

Readily available thermoelectric generators operating under modest temperature differences can power CO2 conversion, according to a proof-of-concept study by chemists. The findings open up the intriguing possibility that the temperature differentials encountered in an array of environments -- from a typical geothermal installation on Earth to the cold, desolate surface of Mars -- could power the conversion of CO2 into a range of useful fuels and chemicals.

The controversies surrounding football’s video assistant referee (VAR) system highlight our troubled relationship with uncertainty – and point to potential solutions

The climate impact of flights taken by the super-rich rose sharply from 2019 to 2023, fuelling calls for a carbon tax on private aviation

Data collected by the Zhurong rover and orbiting satellites suggests the existence of an ancient shoreline in the Utopia Planitia region of Mars

Genetic analysis of five individuals preserved as plaster casts in the ruins of Pompeii contradicts established beliefs about the people and their relationships

If you have good wildlife photos, please send them in, as we always need more.  Today we have a word-and-picture post on butterflies contributed by Athayde Tonhasca Júnior. His words are indented, and you can enlarge the photos by clicking on them:

Fluttering souls

We may be unsympathetic to celebrities who moan about the encumbrances of being gorgeous, but not the Greek princess Psyche. Her striking beauty sent the goddess of love Aphrodite (Venus to the Romans) into a not so loving fit of jealousy. She devised a cunning plan; to dispatch her son Eros (Cupid) on a mission to make Psyche fall in love with the ugliest, wickedest man he could find. But Aphrodite should have taken a hint from her son’s name: Eros spoiled mum’s revenge by falling in love with Psyche. That didn’t work too well for the princess; she became separated from Eros and fell into the clutches of a resentful Aphrodite, who imposed upon her a series of terrible tasks. After many twists and turns worthy of a Mexican telenovela – you can read it all in Metamorphoses – the lovers were reunited. Zeus, Heaven’s Big Cheese, took pity on Psyche. He made her immortal and gave her in marriage to Eros. A happy ending.

Psyche’s tribulations and eventual redemption spoke of mortals’ aspirations, so in her newly acquired divine status, the princess became the goddess of the human soul. For the ancient Greeks, a dying person would breathe out his or her soul, which would fly to the underworld in the form of flickering shadows or spirits. In his History of Animals, Aristotle (384–322 BC) wrote that a butterfly’s cocoon was like a tomb, and the adult insect emerging from it was like the soul fluttering away from a human body after death. It’s no surprise then that the Greek word ψυχή (Psykhe) was used for ‘soul’ and ‘butterfly’. The representation of the soul as a butterfly was an appropriate symbol of the fragility and shortness of life, and that connection explains why goddess Psyche was often represented as a butterfly or as a maiden with butterfly wings.

Psyche, by Pietro Tenerani (1789-1869) © Paolobon140, Wikimedia Commons:

Butterflies have much more to do with humans than merely representing the wanderings of our soul. Their colours and wing patterns, their gentleness and fragility and amazing life cycles have long enthralled naturalists, artists and writers. More books have been written about butterflies than any other insect. Butterflies don’t share the PR problem facing wasps, spiders and other invertebrates that are commonly lumped together as creepy crawlies. Most people like butterflies. Sometimes the attraction is excessive: over-collecting by amateurs, naturalists, and biologists menaces many butterfly species.

The butterfly hunter, by Carl Spitzweg (1808–1885) © Museum Wiesbaden, Wikimedia Commons:

Butterflies are among our commonest and certainly most flamboyant garden visitors. We see them gracefully hopping from flower to flower, probing them with their conspicuous proboscis (tubular, flexible and elongated mouthparts specialised for sucking) for a sip of nectar. So, reasonably, we may assume these plant-insect associations are evidence for psychophily (pollination by butterflies). But that would be a too-hasty conclusion.

Psykhe brought us words such as psychology, psychedelic, psychopath, psycho, psychosomatic, psychomotor and psychophily – the latter illustrated by this pollen-carrying skipper butterfly © Raju Kasambe, Wikimedia Commons:

 

It has long been known that flower visitation does not necessarily result in pollination. That will happen only when pollen grains from the stamen (the male part of the plant) are transferred to the stigma (the female part). But many factors interfere with this process: the visitor may only collect nectar, bypassing the all-important pollen. If pollen is collected, it may be dropped before reaching a receptive stigma, eaten, or taken away to feed the visitors’ brood. Pollen grains passively attached to the visitors’ body may be too few, or located on the wrong part of the body so that it does not contact a stigma. For a variety of reasons, most flower visitations have no bearing of plant fertilisation.

Butterflies are largely nectar drinkers, tapping flowers’ abundant reserves of sugars and amino acids. Some species get their nutrition from ripe or rotten fruit, tree sap, wet soil, animal carcasses and even tears. But with the exception of pollen-munching Heliconius spp. (Young & Montgomery, 2020), butterflies stick to a liquid diet. They rely on their proboscis, an intricate feeding apparatus that works as a drinking straw ranging in length from around 6 mm to a record 52.7 mm for the immaculate ruby-eye skipper (Damas immaculata) (Bauder et al., 2014).

The coiled proboscis of a butterfly © Atudu, Wikimedia Commons:

Pollen is inconsequential to most butterflies. They don’t collect it willingly and their bodies are not adapted to unintentionally transport significant amounts of pollen grains like bees and flies. And that is a problem for plants: they invest a lot of energy producing nectar to attract pollinators. If a visitor goes away with a bellyful of nectar but no pollen, the plant has been a victim of nectar theft (when visitors take nectar without pollinating the flower). Butterflies as a group may have evolved to be nectar thieves, which from the plants’ point of view is nothing short of parasitism (Wiklund et al., 1979). This form of larceny is not restricted to butterflies: bees, flies, birds and most other visitors will steal nectar if given the opportunity (Irwin et al., 2010). But most of the 20,400 or so described species of butterflies don’t compensate their thievery by pollinating their victims.

Butterfly visitors are detrimental or indifferent for a wide range of flowering plants. But, as invariably is the case in biology, things are not simple or straightforward. Butterflies are abundant flower visitors and some species are long distance flyers, therefore with great potential for pollen dispersal. Some plants have not let these traits go to waste: they adopted psychophily as their main or sometimes only means of sexual reproduction. A few plants do that by producing reproductive structures that facilitate pollen transfer by butterfly wings. Others, like the Carthusian pink (Dianthus carthusianorum), hide their nectar at the bottom of narrow, tubular flowers that exclude most visitors, but not butterflies with long proboscises. While moths can take nectar while hovering over a flower, butterflies need to land to feed. The Carthusian pink obliges them with flowers shaped with a flat rim, which is a convenient landing platform for butterflies. This European plant is found in dry, grassy habitats of altitudes of up to 2,500 m, and it depends entirely on butterflies for pollination (Bloch et al., 2006).

Carthusian pink:

In some cases, butterflies intending to commit thievery have the table turned around on them, so that the would-be cheaters become the cheated.

Crucifix orchids (Epidendrum spp.) comprise over 1,400 species distributed from the southeastern United States to northern Argentina. This group of plants is highly diverse morphologically and ecologically, but most investigated species share one feature: a dry cuniculus. This structure is concealed in the column (the fused reproductive parts characteristic of orchids) and normally functions as a nectar reservoir. The majority of crucifix orchids have no nectar to bargain, but that doesn’t deter a range of butterflies. Probably attracted by the orchid’s scents, they probe the flower’s column and cuniculus in search of a non-existent reward. Ending up empty-handed is not the butterflies’ sole unpleasant surprise: the floral tube is narrow and bent, so that a visitor has to struggle to retract its proboscis. This temporary detainment – which could last for over one hour – increases the chances of a butterfly leaving the flower with pollinia (a blob of pollen) attached to its proboscis. This stratagem works very well for the orchids, so that butterflies and some day-flying moths are their only or main pollinators.

(A) Epidendrum densiflorum inflorescence; (B) Dissected flower and detail of column; (C) Flower in longitudinal section, showing the empty cuniculus © Silveira et al., 2023.

Butterflies do not belong to pollinators’ Premier League, but the Carthusian pink, crucifix orchids and several other plants demonstrate that psychophily is not that rare. Butterflies fly over large distances, are attracted to a variety of plants and make repeated visits to flowers. These features must compensate for some of their shortcomings, and we surely have much more to discover about their role in plant reproduction.

Themisto amberwing (Methona themisto), an orchid pollinator © Evaldo Resende, Wikimedia Commons:

Can the Oatzempic diet deliver Ozempic-like weight loss?

The post #Oatzempic – The viral oat-based alternative to Ozempic? first appeared on Science-Based Medicine.

New research into the vulnerability of power grids served by weather-dependent renewable energy sources (WD-RESs) such as solar and wind paints a hopeful picture as various countries around the globe attempt to meet their climate emissions targets -- with the research showing grids with high penetration of WD-RESs tend to have reduced blackout intensities in the US.

Calculations of charge distribution in mesons provide benchmark for experimental measurements and validate widely used 'factorization' method for imaging the building blocks of matter.

The earliest evidence of livestock with modified horns has been discovered in ancient Egypt – sheep skulls with horns that point in unnatural directions suggest humans forced them to grow that way

Shapes created by vortices in water often fall apart, but an odd quantum fluid made from ultracold atoms could support vortex knots that never lose their knottiness