Can You Really Mistake Thrist For Hunger? (Food)

Among common diet advice like “always eat breakfast” and “never eat after 8 p.m.” (do what you want, the timing doesn’t really matter), there’s the old stand-by, “when you think you’re hungry, drink something.” The idea is that it’s easy for your brain to mistake thirst signals for hunger, so you sometimes end up eating extra calories when you could have just chugged a glass of water. Is that really true? According to science, the answer is no.

In a 2008 study published in the Journal of the American Dietetic Association, Purdue University researchers had 128 people record both their feelings of hunger and thirst and everything they ate and drank for one week. They found no evidence that thirst led people to eat. Only feelings of hunger were associated with eating.

But what they did see is even more interesting. 62 percent of the time, people engaged in what the researchers called “inappropriate ingestive behaviors” — things like drinking without being thirsty, eating without being hungry, or not eating or drinking even though they were hungry or thirsty. In other words, more than half the time, people made dietary choices that had nothing to do with the signals their bodies were .

Why don’t people listen to their bodies? According to the researchers, it’s probably because food is so widely available and social snacking is so common that we’ve stopped considering eating and drinking as ways to relieve hunger and thirst. What’s more, our energy sources are all mixed up — some sodas have the same calorie content as a sandwich, and you can eat the same amount of white bread as wheat bread but feel much less satisfied.

So if we’re all that disconnected from our bodies’ signals, what should we do? Drinking plenty of water is still a sure bet, since it doesn’t contain calories and good hydration has all sorts of unexpected benefits. Changing the way you think about food can help, too. According to Harvard Medical School, eating mindfully — with slow, small bites, while appreciating the flavors and aromas — could lead you to eat less overall.

Did Benjamin Franklin Really Want To Make Turkey A National Bird? (History)

There’s a story that starts circulating through the United States every Thanksgiving, around the time that somebody starts carving into the main event. “You know, Benjamin Franklin wanted the turkey to be the national bird, not the bald eagle!” Then everybody laughs, gorges on poultry, and wakes up seven hours later. Except that story is maybe about 15 percent true. Here’s how it really happened.

First things first, let’s just cover what’s true about this story. Benjamin Franklin really did write a letter in which he bemoaned the suitability of the eagle as a national mascot. Here’s the passage that everybody loves to quote:

“For my own I wish the Bald Eagle had not been chosen the Representative of our Country. He is a Bird of bad moral Character. He does not get his Living honestly. You may have seen him perched on some dead Tree near the River, where, too lazy to fish for himself, he watches the Labour of the Fishing Hawk; and when that diligent Bird has at length taken a fish and is bearing it to his Nest for the Support of his Mate and young Ones, the Bald Eagle pursues him and takes it from him.”

A couple of paragraphs later, he completes his thought with the rest of this myth:

“For in Truth the Turkey is in Comparison a much more respectable Bird, and withal a true original Native of America. Eagles have been found in all Countries, but the Turkey was peculiar to ours, the first of the Species seen in Europe being brought to France by the Jesuits from Canada, and serv’d up at the Wedding Table of Charles the ninth. He is besides, tho’ a little vain and silly, a Bird of Courage, and would not hesitate to attack a Grenadier of the British Guards who should presume to invade his Farm Yard with a red Coat on.”

So there you go. Case closed. That’s the whole story, and it turns out Benjamin Franklin really did think that the turkey would have been a better bird. Wait, what was that? A second part of this article? Alright, let’s do some debunking.

So about that letter that Ben wrote — it came two years after the decision about the national seal had already been made. And he wasn’t really talking about the national bird to begin with. And it was all kind of an extended, bird-based pun anyway.

So you need some backstory first. After the Revolutionary War, many of the veteran officers formed a fraternity known as the Society of Cincinnati. It wasn’t an uncontroversial group. Some people complained that membership was hereditary, and others thought that it shouldn’t have used Latin in its official seal. But one complaint came up over and over: the eagle on the seal looked too much like a turkey.

So Franklin’s rumination on the appropriateness of the eagle as a symbol of the nation is more of an aside in a larger conversation about birds and nations in general. And one of the other complaints he levels at the eagle takes on a clear secondary meaning when you realize he’s talking about actual Revolutionary soldiers.

“Besides [the eagle] is a rank Coward: The little King Bird not bigger than a Sparrow attacks him boldly and drives him out of the District. He is therefore by no means a proper Emblem for the brave and honest Cincinnati of America who have driven all the King birds from our Country, tho’ exactly fit for that Order of Knights which the French call Chevaliers d’Industrie.”

Get it? King bird? By the time he starts talking about the turkey — and he’s clearly talking about the “turkey” that appears on the Society of Cincinnati’s seal — it’s evident that he is continuing the joke. The members of the society really didn’t “hesitate to attack a Grenadier of the British Guards” even if they might be “a little vain and silly” with their Latin grandiosity. When it comes down to it, we’re thinking that Benjamin Franklin didn’t actually have very strong feelings about the best bird for the job — personally, we’re voting for the Velociraptor.

Scientists Identified Set Of Genes That Allows Cancer Cells To Avoid Getting Killed By The Immune System (Oncology / Medicine)

The genetic circuits that allow cancer cells to evade destruction by the host immune system remain poorly understood. Now, Keith Lawson and colleagues have identified a phenotypically robust core set of genes and pathways that enable cancer cells to evade killing mediated by cytotoxic T lymphocytes (CTLs) that paves the way for the development of immunotherapies that would be effective for larger patient populations and across different tumour types.

A cancer cell surrounded by immune T killer cells. Credit: National Institutes of Health (NIH)

In order to identify these set of genes and pathways, they performed genome-wide CRISPR screens across a panel of genetically diverse mouse cancer cell lines that were cultured in the presence of CTLs. They identified a core set of 182 genes across these mouse cancer models, the individual perturbation of which increases either the sensitivity or the resistance of cancer cells to CTL-mediated toxicity. Among the resisters were all the genes known to develop mutations in patients who stopped responding to immunotherapy, giving the researchers confidence that their approach worked.

Many of the found genes had no previous links to immune evasion.

Systematic exploration of their dataset using genetic co-similarity revealed the hierarchical and coordinated manner in which genes and pathways act in cancer cells to orchestrate their evasion of CTLs, and showed that discrete functional modules that control the interferon response and tumour necrosis factor (TNF)-induced cytotoxicity are dominant sub-phenotypes.

Their data establish a central role for genes that were previously identified as negative regulators of the type-II interferon response (for example, Ptpn2, Socs1 and Adar1) in mediating CTL evasion, and showed that the lipid-droplet-related gene Fitm2 is required for maintaining cell fitness after exposure to interferon-γ (IFNγ).

In addition, they identified the autophagy (a process when cells ramp up recycling their components to mitigate damage following stress, came up as key for immune evasion) pathway as a conserved mediator of the evasion of CTLs by cancer cells, and showed that this pathway is required to resist cytotoxicity induced by the cytokines IFNγ and TNF. Through the mapping of cytokine- and CTL-based genetic interactions, together with in vivo CRISPR screens, they showed how the pleiotropic effects of autophagy control cancer-cell-intrinsic evasion of killing by CTLs and they highlight the importance of these effects within the tumour microenvironment.

Collectively, these data expand our knowledge of the genetic circuits that are involved in the evasion of the immune system by cancer cells, and highlight genetic interactions that contribute to phenotypes associated with escape from killing by CTLs.

References: Lawson, K.A., Sousa, C.M., Zhang, X. et al. Functional genomic landscape of cancer-intrinsic evasion of killing by T cells. Nature (2020). https://doi.org/10.1038/s41586-020-2746-2 link: https://www.nature.com/articles/s41586-020-2746-2

Crescent Shadow of Messier 87’s Supermassive Black Hole is Wobbling (Astronomy)

The Event Horizon Telescope (EHT) has recently delivered the first resolved images of M87, the supermassive black hole in the center of the M87 galaxy. These images were produced using 230 GHz observations performed in 2017 April. Additional observations are required to investigate the persistence of the primary image feature—a ring with azimuthal brightness asymmetry—and to quantify the image variability on event horizon scales. To address this need, they analyzed M87 data collected with prototype EHT arrays in 2009, 2011, 2012, and 2013. The analysis revealed the behavior of the black hole image across this period, indicating persistence of the crescent-like shadow feature, but also variation of its orientation — the crescent appears to be wobbling.

The EHT Collaboration unveiled the first direct visual evidence of the supermassive black hole in the center of the elliptical galaxy Messier 87 and its shadow. The shadow of a black hole seen here is the closest we can come to an image of the black hole itself, a completely dark object from which light cannot escape. The black hole’s boundary — the event horizon from which the EHT takes its name — is around 2.5 times smaller than the shadow it casts and measures just under 25 billion miles (40 billion km) across. Image credit: EHT Collaboration.

The shape of the black hole’s shadow has remained consistent, and its diameter remains in agreement with Einstein’s theory of general relativity for a black hole of 6.5-billion solar masses.

While their observations do not contain enough information to produce images, they are sufficient to constrain simple geometric models. They developed a modeling approach based on the framework utilized for the 2017 EHT data analysis and validated their procedures using synthetic data. Applying the same approach to the observational data sets, they found the M87* morphology in 2009–2017 to be consistent with a persistent asymmetric ring of ~40 μas diameter. This is an important confirmation of theoretical expectations as the consistency throughout multiple observational epochs gives us more confidence than ever about the nature of M87* and the origin of the shadow.

The position angle of the peak intensity varies in time. In particular, they found a significant difference between the position angle measured in 2013 and 2017. These variations are in broad agreement with predictions of a subset of general relativistic magnetohydrodynamic simulations.

Snapshots of the M87* supermassive black hole appearance, obtained through imaging and geometric modeling, and the EHT array of telescopes in 2009-2017. The diameter of all rings is similar, but the location of the bright side varies. Image credit: M. Wielgus, D. Pesce & EHT Collaboration.

While the crescent diameter remained consistent, the new data also prove it was hiding a surprise: the ring is wobbling. The gas falling onto a black hole heats up to billions of degrees, ionizes and becomes turbulent in the presence of magnetic fields. This turbulence causes the appearance of the black hole to vary over time.

Because the flow of matter falling onto a black hole is turbulent, they can see that the ring wobbles with time. The dynamics of this wobbling allowed them to constrain the accretion flow. The accretion flow contains matter that gets close enough to the black hole to allow th to observe the effects of strong gravity, and in some circumstances, allows them to test predictions from general relativity.

Multiple years of ETH data allow the scientists to perceive the amount of variability in the ring’s appearance. In the current study, the team used data from the proto-EHT, an array that included telescopes at three geographical locations: the Combined Array for Research in Millimeter-wave Astronomy in Cedar Flat, California; the Submillimeter Telescope on Mt. Graham in Arizona; and the Submillimeter Array, the James Clerk Maxwell Telescope and the Caltech Submillimeter Observatory on Maunakea in Hawai’i.

They showed that quantifying the variability across multiple observational epochs has the potential to constrain the physical properties of the source, such as the accretion state or the black hole spin.

References: Maciek Wielgus et al. 2020. Monitoring the Morphology of M87* in 2009-2017 with the Event Horizon Telescope. ApJ 901, 67; doi: 10.3847/1538-4357/abac0d link: https://iopscience.iop.org/article/10.3847/1538-4357/abac0d

SLAC Invention Could Make Particle Accelerators 10 Times Smaller (Physics)

A team led by scientists at the Department of Energy’s SLAC National Accelerator Laboratory has reported the experimental demonstration of a mm-wave electron accelerating structure powered by a high-power rf (radio-frequency) source.

SLAC scientists have invented a copper accelerator structure that could make future X-ray lasers and accelerators for radiation therapy more compact. It feeds terahertz radiation into a tiny cavity to boost particles to tremendous energies. This image shows one half of the structure with the cavity in the circled area. Inset: Scanning electron microscope image of a section of the cavity, which is 3.5 millimeters long and 280 microns wide at its narrowest point. Credit: Chris Pearson/Emilio Nanni/SLAC National Accelerator Laboratory

Unlike today’s accelerators, in which particles draw energy from a radio-frequency (RF) field fed into specifically shaped accelerator structures, or cavities. This new accelerator uses terahertz radiation to boost particle energies. As terahertz waves are 10 times shorter than radio waves, cavities in a terahertz accelerator can also be much smaller. In fact, the one invented in this study was only 0.2 inches long.

The major challenge to build these tiny cavity structures is to machine them very precisely. Over the past few years, SLAC teams developed a way to do just that. Instead of using the traditional process of stacking many layers of copper on top of each other, they built the minute structure by machining two halves and bonding them together.

Researchers in their paper demonstrated reliable coupling of an unprecedented rf power—up to 575 kW into the mm-wave accelerator structure using a quasi-optical setup. This standing wave accelerating structure consists of a single-cell copper cavity and a Gaussian to TM01 mode converter. The accelerator structure is powered by 110 GHz, 10-ns long rf pulses. These pulses are chopped from 3 ms pulses from a gyrotron oscillator using a laser-driven silicon switch.

They showed an unprecedented high gradient up to 230 MV/m that corresponds to a peak surface electric field of more than 520 MV/m. They have achieved these results after conditioning the cavity with more than 105 pulses. They also reported preliminary measurements of rf breakdown rates, which are important for understanding rf breakdown physics in the millimeter-wave regime. These results open up many frontiers for applications not only limited to the next generation particle accelerators but also x-ray generation, probing material dynamics, and nonlinear light-matter interactions at mm-wave frequency.

The authors of the study thank Michael Shapiro, Michelle Gonzalez, Ann Sy, and Gordon Bowden for helpful discussions anf the Fusion Energy Group at General Atomics for equipment loans of quasi-optical equipment that enable low and high-power testing of this structure. Their work was supported by the Department of Energy Contract No. DE-AC02-76SF00515 (SLAC) and Grant No. DE-SC0015566 (MIT). Their work was also supported by NSF Grant No. PHY-1734015.

References: Mohamed A. K. Othman et al, Experimental demonstration of externally driven millimeter-wave particle accelerator structure, Applied Physics Letters (2020). DOI: 10.1063/5.0011397 link: https://aip.scitation.org/doi/10.1063/5.0011397

Indian Astronomers Detected 70 New Variable Stars (Astronomy)

Researchers have presented the first long-term photometric variability survey of the intermediate-age open cluster NGC 559. Time-series V band photometric observations on 40 nights taken over more than three years with three different telescopes are analyzed to search for variable stars in the cluster. They investigated the data for the periodicity analysis and revealed 70 variable stars including 67 periodic variables in the target field, all of them are newly discovered.

The finding chart for the 70 variable stars identified in the observed field of NGC 559 in the V band. The variables belonging to the cluster are shown with circles while variables belonging to the field population are shown by squares. Credit: Joshi et al., 2020.

Located at a distance of about 7,900 light years away from the Earth, NGC 559 is an open cluster estimated to be around 224 million years old. Previous observations of NGC 559 have identified 542 member stars and found that the cluster has a reddening at a level of 0.82 mag, and that its radius containing half the members is about 4.86 arcmin.

In the new study, study detected 70 new variable stars, out of which 67 are periodic variables with periodicities ranging from three hours to 41 days. The vast majority of the newfound periodic variables have periods below one day and most of them have relatively small amplitude of variability down to 0.02 mag level.

Their membership analysis of the periodic variables revealed that 30 of them belong to the cluster, with estimated masses between 1.72 and 3.6 solar masses, and remaining 37 are identified as field variables. Out of the 67 periodic variables, 48 are short-period (P<1 day) variables and 19 are long-period (P>1 day) variables. The variable stars have periodicity between 3 hours to 41 days and their brightness ranges from V = 10.9 to 19.3 mag.

The periodic variables belonging to the cluster are then classified into different variability types on the basis of observational properties such as shape of the light curves, periods, amplitudes, as well as their positions in the Hertzsprung-Russell (H-R) diagram. As a result, researchers identified one Algol type eclipsing binary, one possible blue straggler star, 3 slowly pulsating B type stars, 5 rotational variables, 11 non-pulsating variables, 2 FKCOM variables and remaining 7 are characterized as miscellaneous variables. They also identified three Eclipsing Binary stars (EBs) belonging to the field star population. The PHOEBE package is used to analyse the light curve of all four EBs in order to determine the parameters of the binary systems such as masses, temperatures and radii.

References: Yogesh C. Joshi, Ancy Anna John, Jayanand Maurya, Alaxendra Panchal, Brijesh Kumar, Santosh Joshi, “Variable stars in the field of intermediate-age open cluster NGC 559”, pp. 1-15, 2020. arXiv:2009.06997 [astro-ph.SR] arxiv.org/abs/2009.06997 link: https://arxiv.org/abs/2009.06997

Scientists Create World’s Smallest ‘Refrigerator’ (Nanotechnology / Engineering)

If you’re anything like me, you probably wish your refrigerator was at least a little bit bigger. It seems to fill up fast (especially when you fail to eat leftovers, which I’m guilty of), but researchers from UCLA decided to take things in the opposite direction by creating what they are calling the world’s smallest refrigerator.

Two flakes of semiconductor material create a tiny cooling chamber. Image source: UCLA/Regan Group

In actually, it’s a tiny thermoelectric cooler that is just 100 nanometers thick. For some sense of scale, one nanometer is equivalent to 0.0000001 centimeters. Yeah, it’s pretty tiny, and while it doesn’t initially seem to have any useful applications in the average home kitchen, it could be a breakthrough in cooling powerful electronics, which tend to get very hot.

The tiny “refrigerator” was made using semiconductors that get either hot or cold depending on their orientation and design. When one side is heated, the other side becomes cold, and that’s extremely useful in cooling technologies and can even be used to generate electricity. Scientists know that they work on larger scales, but the team from UCLA shrunk the entire thing down to a size that you can’t even see with the naked eye.

Using simple tape to peel impossibly tiny flakes of semiconductor material off of a larger piece, they then combined them in the same way that they would with a much larger version. The two semiconductors were bismuth telluride and antimony-bismuth telluride. The tiny flakes worked just as they do in conventional applications with much larger components.

But why bother to make something so tiny in the first place? Well, the goal is to get a better idea of how the cooling process works on an incredibly small scale and then use that knowledge to build larger versions that are as efficient as they can possibly be.

A standard thermoelectric device, which is made of two semiconductor materials sandwiched between metalized plates. Credit: Wikimedia Commons

“Its small size makes it millions of times faster than a fridge that has a volume of a millimeter cubed, and that would already be millions of times faster than the fridge you have in your kitchen,” UCLA physics professor Chris Regan, co-author of the research, said in a statement. “Once we understand how thermoelectric coolers work at the atomic and near-atomic level, we can scale up to the macroscale, where the big payoff is.”

So, no, you won’t be seeing thermoelectric, semiconductor-powered cooling technology in your next refrigerator, but this certainly won’t be the last you hear of it.

This article is republished here from bgr under common creative licenses..

References: William A. Hubbard et al. Electron-Transparent Thermoelectric Coolers Demonstrated with Nanoparticle and Condensation Thermometry, ACS Nano (2020). DOI: 10.1021/acsnano.0c03958 link: https://pubs.acs.org/doi/10.1021/acsnano.0c03958

This Is How You Can Create ‘Green’ Protein From The Air (Chemistry)

To adhere to the Paris Agreement of 2015, there’s a need to store several Gigatonnes (Gt) of carbon annually. In the last years, a variety of technologies for carbon capture and storage (CCS) and carbon capture and usage (CCU) have been demonstrated. While conventional CCS and CCU are techno-economically feasible, their climate change mitigation potentials are limited, due to limited amount of CO2 that can be captured.

Now, Pikaara and colleagues in their paper, discuss an interesting alternative route for capture of carbon dioxide from industrial point sources, using CO2-binding, so-called “autotrophic aerobic bacteria” to produce microbial biomass as a C-storage product.

Procedure. Credit: Ilje Pikaara et al.

The produced microbial biomass is often referred to as microbial protein (MP) because it has a crude protein content of ~70–75%. Depending on the industrial production process and final quality of the produced MP, it can be used for human consumption as meat replacement, protein supplement in animal diets, or slow-release organic fertilizer thus providing both organic nitrogen and carbon to agricultural soils.

They also discussed the potentials and limitations of this so far unexplored CCU approach. A preliminary assessment of the economic feasibility of the different routes for CO2 carbon avoidance, capture and utilization indicates that the value chain to food is becoming attractive and that the other end-points warrant close monitoring over the coming years.

References: Ilje Pikaara, Jode Vriezec, Korneel Rabaey, Mario Herrero, Pete Smith, Willy Verstraete, “Carbon emission avoidance and capture by producing in-reactor microbial biomass based food, feed and slow release fertilizer: Potentials and limitations”, Science of The Total Environment
Volume 644, 10 December 2018, Pages 1525-1530. Doi: https://doi.org/10.1016/j.scitotenv.2018.07.089 link: https://www.sciencedirect.com/science/article/abs/pii/S0048969718325749?via%3Dihub

Why Do Some People Tolerate Spicy Food Better Than Others? (Food)

You’ve probably noticed that people have widely different tolerances, when it comes to spicy food. Your friend can eat an entire bowl of chilli doused with extra hot sauce, while you say or me, maybe we have to send that bowl back to the kitchen and order something little less spicy. Well, scientists don’t know for sure what allows some people to gulp down habanero salsa.

For one thing, some people may simply be born with less sensitivity to spice. That’s because spiciness is detected by a sensory receptor called TRPV1, is a little protein that opens up in response to physical temperature, but also when fiery molecules like capsiacin bind to it which is why a bite of jalapeño will make your tongue feel like its on fire.

Scientists know that gene sequences that produce the TRPV1 Protein vary from person to person so it could be that certain versions of the receptor are more or less responsive than others. There’s also the matter of how much you use your TRPV1 receptors.

Lots of studies have documented a kind of desensitization effect, where people who eat alot of capsiacin — the compound that makes hot peppers spicy —will have to eat even more capsiacin in order to taste the same level of spiciness. So people might have higher spice tolerances because as they eat spicy food more regularly, they literally aren’t feeling as much burn.

Another theory suggests that its not that spicy food burns less for some people, instead, its that some people like the burn. If you can grow up eating tamales or curry, it could be that you simply learn to enjoy the sensation because of repeated exposure or the burn itself could be the real draw.

After all, ask any chili-head if they can feel the heat and they most certainly tell you that they can.. One psychologist calls this phenomenon benign masochism.

One study has even linked this to personality type. Among a group of mostly white college students, people who reported liking spicy foods were more likely to be sensation-seekers.

So, if you have a high spice tolerance, it could be partly because of your genes or because you’re on a constant diet of tabasco sauce that lowers your sensitivity. But, its most likely to be because you’ve simply learned to enjoy that tongue-tingling.

Eternal in Knowledge, Eternal in Contents..