Can Science Tell Us What The Best Travel Insurer Is?

Funny title, we know. But that’s exactly the question we’d like to answer, by using an automated approach to read all the comments, reviews and information about any given travel insurer. When it comes to travel insurance for digital nomads, there are a few monster players in that industry, with World Nomads perhaps being the biggest one. We’ve read a lot of different articles on this company and consider this compilation of World Nomads reviews to probably be the best article on them so far, as you get a range of different responses from customers who like them, dislike them and are somewhat neutral. This is in contrast to many articles that are overwhelming positive or overwhelmingly negative.


Official Website

LinkedIn profile

Review by hostel geeks

Alpha Draconis: astronomers discover that it’s a binary eclipsing system

The binary system of Alpha Draconis (also known as Thuban), a system visible even to the naked eye and well studied 270 light years away from us, is actually an eclipsing binary system. Eclipsing binary systems are those in which the two stars, from our point of view, eclipse each other, i.e. they pass one in front of the other. This surprised the same researchers who discovered this important feature using data from NASA’s TESS telescope.

The system is made by a primary star 4.3 times the size of the Sun, and a companion star probably half the size of the primary star.

“The first question that comes to mind is ‘How did we miss this?'”, says Angela Kochoska, a researcher at Villanova University in Pennsylvania who presented her findings at the annual meeting of the American Astronomical Society in Honolulu.

Probably this feature has never been detected until now because eclipses, being quite short (they last about six hours) can be easily lost from Earth and, being the star so bright, the thing appeared “hidden” also other space detectors. This is one of the brightest known eclipsing binary systems in which the two stars are widely separated and interact only gravitationally (they don’t exchange materials).

These systems are very important for astronomers because it is possible to measure their masses and dimensions with unprecedented accuracy.

Researchers have found that stars orbit every 51.4 days at an average distance that is slightly greater than the average distance between mercury and the Sun. From our point of view, however, neither is ever completely covered by its companion and so it is a partial eclipse.

The speed of the black hole jet of M87 has been measured

A team of astronomers has studied in greater detail the jet of materials and gas that escapes from the black hole at the center of the galaxy Messier 87, or M87, the black hole that was so prominent last year when astronomers published the first ever image of such an object.

This supermassive black hole, with a mass of 6.5 billion times that of the Sun, is located 500 million light-years away from Earth and is characterized by a very powerful jet of particles that come out at very high energy and very high speed as they “bounce” before being sucked into the event horizon of the black hole itself. Researchers have studied this jet at various wavelengths of light, including X-rays, also using the Chandra Space Telescope.

The results confirm that these jets coming out of supermassive black holes can reach speeds close to that of light. This is the first time that the speed of an object emerging from a black hole is recorded using X-ray data, as explained by Ralph Kraft of the Center of Astrophysics | Harvard & Smithsonian (CfA) in Cambridge. In fact, to make precise measurements of the speed of these jets, you need sharp X-ray vision, something that probably, at the moment, only the Chandra telescope can allow.

These jets, also called “relativistic jets”, are made of materials that initially form part of the swirling growth disk that rotates around the black hole at the center of the galaxy. Part of this material falls inside the black hole while another part is redirected at very high speed, in the form of narrow beams with real jets, along the magnetic field paths of the black hole itself.

In calculating the speed of the black hole’s object at the center of the galaxy M87, the researchers obtained the first example of a phenomenon called “superluminal movement” which, only apparently, sees sections of this jet move at speeds greater than the speed of light. This is just an optical effect that happens when these jets, travelling at very high speeds close to those of light, point in our direction.

The jet seems to travel towards us almost as fast as the light it generates and this generates the illusion, even measurable, that the jet’s motion is faster than light itself.

Researchers have measured an apparent speed of 6.3 times that of light for the “node” of the nearest black hole jet (a “node” is a kind of brighter lump that forms along the jet due to the irregularity of its fall).

Gravitational waves from the collision between two neutron stars have been intercepted

The LIGO observatory in collaboration with the Virgo observatory has captured the gravitational waves of another collision event that most likely is the fusion clash between two neutron stars.
The first data was collected on April 25, 2019 and the related study was then published in Astrophysical Journal Letters.

This is a “very interesting” binary system, as reported by Alberto Vecchio, director of the Institute of Gravitational Wave Astronomy at the University of Birmingham, because the sum of the masses of the two neutron stars is the highest ever observed in a binary system. So high that perhaps we could talk about a new class of binary systems of neutron stars, a class that is substantially different from the similar binary systems we have identified so far.

At the moment, however, it cannot yet be ruled out that one of the members of the system is in fact a black hole. This is the second time that two neutron stars orbiting each other during fusion are detected through the reception of gravitational waves. The first such detection took place in August 2017.

Unlike the first time, this time no light was detected but only the gravitational wave data that suggested that fusion led to the creation of a new object with “an unusually high mass,” as reported in the press release that appeared on the website of the English University.

The study was carried out in collaboration with researchers from the Virgo Observatory in Italy and the results were presented during the meeting of the American Astronomical Society in Honolulu.

Scientists study testicles of gnats to understand production of particular genes

Analyzing the testicles of fruit flies, a group of researchers at Rockefeller University confirmed that the testicles themselves are not only “sperm factories” but can also be used to create new genes.

In their research, published in eLife, the researchers studied a number of genes originated in the testicles discovered by other research in recent years. They identified and decoded the RNA sequences contained in individual cells within the testicles and eventually marked them to follow their development.

They analyzed particular types of young genes that are born from scratch rather than duplicating existing genes. About 15% of these new genes appeared at the beginning of cell development, even in stem cells, which surprised the researchers themselves. The most active period for genes born from scratch occurred at mid-flow, in the so-called spermatocyte phase, i.e. the development of sperm.

Gold scientists also want to understand what these new genes are for because some of them seem to appear by chance and make no contribution to development even though Li Zhao, the scientist who led the research, thinks that they play a role in the maturation of sperm cells.

New research will be needed to understand what these genes are used for and what precisely their role is.

Dinosaurs proliferated thanks to a sudden increase in oxygen 215 million years ago

According to a study presented at the Goldschmidt conference in Barcelona, the increase in oxygen levels that occurred 215 million years ago would be linked to the rise of dinosaurs in the area of present-day North America.

Researchers measured oxygen levels in some ancient rocks in North America and saw a peak in oxygen levels with the latter increasing by almost a third in just three million years. This increased availability of oxygen, according to the researchers, would be linked to an expansion of dinosaurs, and not only in North America.

The researchers used a new technique to measure the gases trapped inside the rocks. The method involves the use of a mass spectrometer that measures the composition of the gases. The researchers analyzed the rocks of the Colorado plateau and the Newark basin, two conglomerates that formed more or less at the same time and were separated by about 600 miles away in the supercontinent of Pangea.

Analysis has shown that in about 3 million years, just over the blink of an eye in geological terms, oxygen levels have increased from about 15% to about 19% (today we are at 21%). Schaller still does not know what may have caused this “sudden” increase, probably there is a global climate change that has also seen a drop in carbon dioxide levels.

However, he has discovered that it was dinosaurs in particular that took advantage of it: during the oxygen peak, the first dinosaurs appeared in the North American tropics, areas that at the time of the supercontinent Pangaea were located near the equator, particularly those of the genus Chindesaurus.

These last ones were then followed by the sauropods and by a wide evolutionary diversification. Oxygen levels may not have been the only determining factor, according to Schaller himself.

Nanoparticles in the eyes allow mice infrared night vision

A nanoparticle-based technology that could perhaps one day allow humans an integrated night vision within their visual system has been developed by a group of researchers from the School of Medicine at the University of Massachusetts. Gang Han, the main author of the research, is in fact performing several experiments on mice by injecting into their eyes a special nanomaterial made from nanoparticle conversion (upconversion nanoparticles, UCNP).

These are organic particles that contain traces of rare earths, erbium and ytterbium that can convert the photons of infrared light into high-energy green light, i.e. light that mammals’ eyes can intercept.

The special nanoparticles have been attached to the photoreceptors of mice’s eyes with a protein bound in turn to a sugar molecule on the surface of the photoreceptors. After this first stage, they injected them behind the retinas.

They then started to test to see if the eyes could see infrared light. In the first phase, the mice were trained to swim towards a visible light that signaled the escape route. In a second phase, the visible light was replaced by infrared light.

Mice with special nanoparticles in their eyes could also see the escape route signal, unlike other mice that had not been injected.

After 10 weeks, the nanoparticles had not yet caused any obvious side effects, although Han himself admits that the level of biocompatibility is not yet completely clear at this stage and that further research will also have to be done to consider possible use in humans.

Breathalyzer invented that detects marijuana in the breath

Marijuana is becoming increasingly legal in the United States, but there are limits on its use, just as there are limits on alcohol when driving, for example.

Unlike marijuana, however, there is no quick device for marijuana to check, for example by breathing, the amount taken, as is done with a breathalyzer for alcohol. This is a real problem for the police force and for those in charge of controls in general.

A team of researchers from the Department of Chemistry and the Swanson School of Engineering at the University of Pittsburgh has therefore built one. It is a device that can measure the amount of tetrahydrocannabinol (THC), the active compound present in marijuana itself, by breath alone.

Currently, to check the presence of this compound in the body, analyses of blood, urine or hair samples must be carried out, processes that cannot be carried out naturally, for example, at a checkpoint or at a checkpoint.

The device is constructed with carbon nanotubes capable of capturing the THC molecules present in the breath. Once captured, the surface of the nanotubes changes its electrical properties, which signals the presence of the compound.

These nanotechnological sensors detect THC with a degree of accuracy comparable or even better than mass spectrometers.

In addition, as Sean Hwang, one of the authors of the study as well as the manufacturers of the device, explains, automatic learning technique was also used to “teach” the device to recognize the presence of THC even when there are other imperceptible substances in the breath.

Externally it is similar to a classic breathalyzer: it boasts a plastic casing and mouthpiece plus a small digital display indicating the measurement.