вторник, 1 января 2019 г.

Follow the Brainbow In 2007 scientists and artists alike were…

Follow the Brainbow

In 2007 scientists and artists alike were first entranced by ‘Brainbow’ – a tool that illuminates the brain in a whirl of colour, with each cell, or neuron, glowing a unique hue. Researchers began untangling the brain’s complex web of connections, but soon found Brainbow’s limits. Neurons have long, thin projections called axons, and the fluorescent colours aren’t bright enough to clearly show their full spindly length, so tracking their paths can take months. Now a new technique takes the concept one step further, imbuing neurons with even brighter colours, making even the finest strands more visible and dramatically reducing the time it takes to track them. Named ‘Tetbow’ after the antibiotic tetracycline, which it uses to control gene expression, this illuminating approach reveals the most intricate details of 3D structure such as the fine tufts visible in the olfactory bulb [part of the brain involved in smell] section pictured.

Written by Anthony Lewis

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Merrivale Stone Row 1, Dartmoor, Devon, 29.12.18.When I visited here last year, I looked...

Merrivale Stone Row 1, Dartmoor, Devon, 29.12.18.

When I visited here last year, I looked out on a landscape in glorious sun but with frozen ground. This visit was shrouded in thick fog which made it all the more atmospheric. Loved it!

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jason-1971: Avebury standing stones


Avebury standing stones

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Dynamo-amplification and magnetic driven outflows in Milky Way-like galaxies

Figure 1: These views show the galaxy in a simulation where the magnetic field is seeded into the ISM with each supernova that occurs. The top and bottom rows show face-on and edge-on views, respectively, with gas density (first and third column) and magnetic field strength (second and fourth column) shown at two different times in the evolution of the galaxy. At 2 billion years (first and second column), thermal pressure is dominating in the galactic disc and outflows due to the magnetic field are not possible. At 3 billion years, the magnetic pressure is dominating and magnetic outflows are possible, which are happening in two cones perpendicular to the disc. Although these cannot be very well identified in the gas-density itself, they can be seen in the magnetic field strength as two lobes above the disc. © MPA

Lately, the impact of magnetic fields in simulations of galaxy formation and evolution is being widely studied. However, it is still unclear to which degree magnetic fields influence the formation and evolution of galaxies. A team of researchers from the astronomical Max Planck Institutes in Garching, the University Observatory in Munich, and the University of Konstanz have introduced a new galactic model with an explicitly modelled circum galactic medium (CGM) to investigate the impact of magnetic fields in an isolated simulation of a Milky Way-like galaxy with the focus on the dynamo amplification of the magnetic field. Further the researchers discuss the possibility of bi-conical magnetic driven outflows and their impact on the star formation rate of the galaxy.

Magnetic fields can be important for many physical processes in galaxy formation and evolution; yet it is poorly understood how magnetic fields change this picture. In galaxies with halo masses above 10 billion solar masses they can be quickly amplified from a small seed field to a few µG in the galactic disc. In this scenario there are three main amplification processes for magnetic fields: adiabatic compression, the so called α-ω-dynamo, and the small-scale turbulent dynamo. Once magnetic fields are amplified via one of these three processes they have the ability to launch a galactic wind if the magnetic pressure is in the same order of magnitude (or higher) than the thermal pressure.

Amplification via adiabatic compression is an effect of ideal magneto hydrodynamics (MHD), which is caused when the gas in the centre of a dark matter halo collapses, leading to compressed field lines and therefore an amplification of the magnetic field. In this case the magnetic field strength and the density are correlated by a simple power law relation (B ~ ρ2/3). The α-ω-dynamo can amplify magnetic fields in both the linear and the non-linear regime through small-scale buoyant flows (alpha-effect) and large-scale rotation of the disc (omega-effect). The small scale turbulent dynamo can lead to linear and non-linear amplification of the magnetic field due to turbulence in the interstellar medium (ISM). In this case, the turbulence is introduced by supernova-feedback, leading to a similar behaviour as for the α-ω-dynamo (but different physical origin). However, both effects can be clearly distinguished through their respective power spectrum. If both dynamo processes are acting simultaneously the net effect is called α2-ω-dynamo.

Figure 2: Bi-conical outflow in the magnetic field shortly after its onset at 2.4 billion years in the simulation; the outflow appears in both magnetic field models. The outflow is very prominent in the magnetic field strength, reaching values of up to a few 10 µG, which is comparable with values observed for the Fermi-bubbles reaching far into Milky Ways’ CGM. In terms of morphology and velocity, the outflow structure is closer to a wind that is driven by an active galactic © MPA

A team of researchers from the astronomical Max Planck Institutes in Garching, the University Observatory in Munich and the University of Konstanz have carried out high resolution simulations of isolated Milky Way-like galaxies to study the details of these dynamo processes and the consequences of magnetic driven outflows on the general properties of the galaxy. The research team introduced a new galactic model for isolated galaxies including a hot circum galactic medium (CGM) around the central disc, embedded in a dark matter halo. This provides a more realistic framework to model inflows from the hot CGM and effects of magnetic fields can be studied with the Tree-Smooth-Particle-Magneto-Hydrodynamics-(SPMHD)-code Gadget-3.

Moreover, the team investigated the impact of different initial conditions for the magnetic field. The fiducial model is the so called ‘supernova-seeding model’, in which the magnetic field is given to the ISM in a dipole structure with every exploding supernova. This model assumes that magnetic fields are generated in stars via dynamo action. The alternative model postulates a (small) constant seed field parallel to the disc, assuming that such small seed-fields are generated before inflation and get further amplified during inflation.

The research team finds a magnetic outflow perpendicular to the galactic disc in two cones that reduces the star formation rate substantially. At the end of the simulation (4 Gyr), the star formation rate is roughly half compared to a run without magnetic fields. Further, the mass of the disc is slightly reduced with outflows carrying away between 0.2 and 1.0 solar masses per year. For both magnetic field models the magnetic field strength saturates at a few µG in agreement with observations. The morphology of the simulated galaxy with the fiducial model is displayed in Fig.1. The biconical shape of the outflow is displayed in Fig.2.

Figure 3: Median magnetic field strength for the simulation with supernova seeding (red) as well as the 1σ (dark gray region) and 2σ (light gray region) errors. The orange line shows a relation known from magneto-hydrodynamics theory, indicating amplification by adiabatic compression. The highest magnetic field strengths correlate with the highest gas densities. In the centre the amplification of the magnetic field is driven by both adiabatic compression and small scale turbulence. In the spiral arms the magnetic field is lower and is mainly amplified by adiabatic compression. The magnetic field strength in the inter arm regions, i.e. the less dense areas between the spiral arms, shows a higher magnetic field than could be explained by adiabatic compression. Here the magnetic field is amplified by small scale turbulence. In the outskirts of the galaxy the amplification is not driven by adiabatic compression because the simulation is not following the scaling law known from ideal MHD. [less] © MPA 

The amplification process of the magnetic field is complicated, but the research team was able to find strong evidence for an α2-ω-dynamo for early times which transfers to an ordinary α-ω-dynamo at late times when the amplification by small-scale turbulence is suppressed by declining supernova-rates and strong magnetic fields that further supress turbulence in the ISM. Further, the research team could identify different regions within the galactic disc to evaluate the contribution to the amplification of the magnetic field by adiabatic compression (Fig. 3).

For the first time with a particle based method, the research team was able to show that their simulations agreed both with predictions from dynamo theory and with observations of magnetic fields in nearby galaxies. They were able to recover the observed saturation field strengths after a non-linear growth phase of the magnetic field in the simulation. Further, they were able to reproduce the observed morphological appearance of galactic magnetic fields that did not appear in other numerical simulations of the same kind.


Ulrich Steinwandel for the research team

Ulrich Steinwandel, Klaus Dolag and Benjamin Moster (Max Planck Institute for Astrophysics, Garching / University Observatory Munich)

Alexander Arth (University Observatory Munich, Max Planck Institute for Extraterrestrial Physics, Garching)

Original Publication

U. P. Steinwandel ,M. C. Beck, A. Arth, K. Dolag, B. P. Moster, P. Nielaba

Magnetic buoyancy in simulated galactic discs with a realistic circumgalactic medium

MNRAS Volume 483, Issue 1, 11 February 2019, Pages 1008–1028

Source / DOI

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ALMA Discover Early Protostar With a Warped Disk

Artist’s impression of a warped disk around a protostar. ALMA observed the protostar IRAS04368+2557 in the dark cloud L1527 and discovered that the protostar has a disk with two misaligned parts. Credit: RIKEN

Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, researchers have observed, for the first time, a warped disk around an infant protostar that formed just several tens of thousands of years ago. This implies that the misalignment of planetary orbits in many planetary systems, including our own, may be caused by distortions in the planet-forming disk early in their existence.

The planets in the Solar System orbit the Sun in planes that are at most about seven degrees offset from the equator of the Sun itself. It has been known for some time that many extrasolar systems have planets that are not lined up in a single plane or with the equator of the star. One explanation for this is that some of the planets might have been affected by collisions with other objects in the system or by stars passing by the system, ejecting them from the initial plane.

However, the possibility remained that the formation of planets out of the normal plane was actually caused by a warping of the star-forming cloud out of which the planets were born. Recently, images of protoplanetary disks, rotating disks where planets form around a star, have in fact showed such warping. But it was still unclear how early this happened.

In the latest findings, published in Nature, the group from the RIKEN Cluster for Pioneering Research (CPR) and Chiba University in Japan have discovered that L1527; an infant protostar still embedded within a cloud, has a disk that has two parts, an inner one rotating in one plane, and an outer one in a different plane. The disk is very young and still growing. L1527, which is about 450 light years away in the Taurus Molecular Cloud, is a good object for study as it has a disk that is nearly edge-on to our view.

According to Nami Sakai, who led the research group, “this observation shows that it is conceivable that the misalignment of planetary orbits can be caused by a warp structure formed in the earliest stages of planetary formation. We will have to investigate more systems to find out if this is a common phenomenon or not.”

The remaining question is what caused the warping of the disk. Sakai suggests two reasonable explanations. “One possibility,” she says, “is that irregularities in the flow of gas and dust in the protostellar cloud are still preserved and manifest themselves as the warped disk. A second possibility is that the magnetic field of the protostar is in a different plane from the rotational plane of the disk, and that the inner disk is being pulled into a different plane from the rest of the disk by the magnetic field.” She says they plan further work to determine which is responsible for the warping of the disk.

Additional Information

This research has been published in Nature (Advanced Online Publication) under the title “Warped disk around an infant protostar” by N. Sakai et al.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) in Taiwan and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

RIKEN is Japan’s largest research institute for basic and applied research. Over 2500 papers by RIKEN researchers are published every year in leading scientific and technology journals covering a broad spectrum of disciplines including physics, chemistry, biology, engineering, and medical science. RIKEN’s research environment and strong emphasis on interdisciplinary collaboration and globalization has earned a worldwide reputation for scientific excellence.


Jens Wilkinson
RIKEN Global Communications
Phone: +81-(0)48-462-1225
Email: pr@riken.jp

Nicolás Lira
Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago – Chile
Phone: +56 2 2467 6519
Cell phone: +56 9 9445 7726
Email: nicolas.lira@alma.cl

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
, Tokyo – Japan
Phone: +81 422 34 3630
Email: hiramatsu.masaaki@nao.ac.jp

Calum Turner
ESO Assistant Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: calum.turner@eso.org

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Phone: +1 434 296 0314
Cell phone: +1 202 236 6324
Email: cblue@nrao.edu

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The PIE homeland controversy: January 2019 status report

Last year, the preprint that claimed to have presented archaeogenetic data that opened up the possibility of the Proto-Indo-European (PIE) homeland being located south of the Caucasus was, ironically, also the preprint that considerably strengthened my belief that the said homeland was actually located north of the Caucasus.

Of course, I’m talking about the Wang et al. manuscript at bioRxiv, which is apparently soon to be published as a peer-reviewed paper in Nature Communications.

It’ll be fascinating to check if and how the peer-review process has impacted on the preprint, and especially its conclusion. My impression was that the authors seemed pretty sure that the Maykop people gave rise to the Yamnaya culture, or at least Indo-Europeanized it. But, as far as I saw, the archaeogenetic data didn’t bear this out at all, and instead showed a lack of any direct, recent and meaningful genetic relationship between Maykop and Yamnaya (see here). Was this also picked up by the peer reviewers? We shall see.

Moreover, there was some exceedingly interesting fine print in the manuscript’s supplementary information:

Complementary to the southern [Darkveti-Meshoko] Eneolithic component, a northern component started to expand between 4300 and 4100 calBCE manifested in low burial mounds with inhumations densely packed in bright red ochre. Burial sites of this type, like the investigated sites of Progress and Vonyuchka, are found in the Don-Caspian steppe [10], but they are related to a much larger supra-regional network linking elites of the steppe zone between the Balkans and the Caspian Sea [16]. These groups introduced the so-called kurgan, a specific type of burial monument, which soon spread across the entire steppe zone.

Always read the fine print, they say. And they’re right. Imagine if I only read the preprint’s conclusion and missed this little gem; I’d probably think that the PIE homeland was located south of the Caucasus rather than on the Don-Caspian steppe.

Wow, proto-kurgans with inhumations densely packed in bright red ochre? A supra-regional network linking the elites of the steppe all way from the Balkans to the Caspian Sea? An expansionist culture? And, as evidenced by the ancient DNA from the Progress and Vonyuchka sites, a people who may well have been in large part ancestral to the Yamnaya, Corded Ware and Andronovo populations, that have been identified based on archeological and historical linguistics data as the main vectors for the spread of Indo-European languages as far as Iberia in the west and the Indian subcontinent in the east.

I wonder if the authors actually asked themselves who these people may have been, before so haphazardly turning to Maykop and, ultimately, the Near East, as the likely sources of the Yamnaya culture? To me they look like the Proto-Indo-Europeans and true antecedents of Yamnaya.

So as things stand, my pick for the PIE homeland is firmly the Don-Caspian steppe. And I genuinely thank Wang et al., and indeed the Max-Planck-Institut für Menschheitsgeschichte (aka MPI-SHH), for their crucial assistance in this.

But, you might ask, what about the Hittites? Yes, I realize that no one apart from me and a few of my readers here can find any steppe ancestry in the so called Hittite genomes published to date. However, consider this: if the PIE homeland really was on the steppe, and a dense sampling strategy of Hittite era Anatolia fails to turn up any unambiguous steppe ancestry in at least a few individuals, then there has to be an explanation for it. But let’s wait and see what a dense sampling strategy of Hittite era Anatolia actually reveals before we go that far.

See also…

Late PIE ground zero now obvious; location of PIE homeland still uncertain, but…
On the doorstep of India


‘Spinster’s Rock’ Dolmen, Dartmoor, Devon, 30.12.18.This is another...

‘Spinster’s Rock’ Dolmen, Dartmoor, Devon, 30.12.18.

This is another first visit for me and to date this is the only known Neolithic portal dolmen on Dartmoor. Whilst very striking, the fact that it was re-erected in the 19th century makes it more complex to study. Local folklore states three spinsters built it before breakfast one day.

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Soussons Common Cairn Circle, Dartmoor, Devon, 30.12.18.This was a first visit for me and...

Soussons Common Cairn Circle, Dartmoor, Devon, 30.12.18.

This was a first visit for me and this is a picturesque cairn situated amongst a forestry commission plantation. The remains of the cairn centre can be discerned in the centre of the site although it is often mistaken as a stone circle. It is thought that when the cairn was constructed it would have offered commanding views of the area with few trees.

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Aquamarine & Orthoclase | #Geology #GeologyPage…

Aquamarine & Orthoclase | #Geology #GeologyPage #Mineral

Locality: Erongo Mountains, Erongo Region, Namibia

Size: 4.3 × 7.7 × 5 cm

Largest Crystal: 2.30cm

Photo Copyright © Thames Valley Minerals /e-rocks. com

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Barite with Realgar | #Geology #GeologyPage #Mineral Location:…

Barite with Realgar | #Geology #GeologyPage #Mineral

Location: Baia Sprie, Maramures Co., Romania

Size: 10.5 x 8.5 x 6.5 cm (cabinet)

Photo Copyright © Weinrich Minerals

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Elbaite | #Geology #GeologyPage #Mineral Location: Himalaya…

Elbaite | #Geology #GeologyPage #Mineral

Location: Himalaya Mine, San Diego Co., California, USA

Size: 11.0 x 1.8 x 1.8 cm (cabinet)

Photo Copyright © Weinrich Minerals

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Punalu’u Beach “Black Sand Beach” | #Geology…

Punalu’u Beach “Black Sand Beach” | #Geology #GeologyPage #BlackSand #Hawaii

Punalu’u Beach (also called Black Sand Beach) is a beach between Pahala and Na?alehu on the Big Island of the U.S. state of Hawaii.

The beach has black sand made of basalt and created by lava flowing into the ocean which explodes as it reaches the ocean and cools. This volcanic activity is in the Hawaii Volcanoes National Park. Punalu?u is frequented by endangered hawksbill and green turtles, which can often be seen basking on the black sand.

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2018 December 31 The Witch Head Nebula Image Credit &…

2018 December 31

The Witch Head Nebula
Image Credit & Copyright: Digitized Sky Survey (POSS II); Processing: Utkarsh Mishra

Explanation: Double, double toil and trouble; Fire burn, and cauldron bubble …. maybe Macbeth should have consulted the Witch Head Nebula. A frighteningly shaped reflection nebula, this cosmic crone is about 800 light-years away though. Its malevolent visage seems to glare toward nearby bright star Rigel in Orion, just off the right edge of this frame. More formally known as IC 2118, the interstellar cloud of dust and gas is nearly 70 light-years across, its dust grains reflecting Rigel’s starlight. In this composite portrait, the nebula’s color is caused not only by the star’s intense bluish light but because the dust grains scatter blue light more efficiently than red. The same physical process causes Earth’s daytime sky to appear blue, although the scatterers in planet Earth’s atmosphere are molecules of nitrogen and oxygen.

∞ Source: apod.nasa.gov/apod/ap181231.html

Entry Route The early symptoms of a hantavirus infection –…

Entry Route

The early symptoms of a hantavirus infection – fatigue, fever and muscle aches – are similar to countless other viral infections, but as the disease progresses, the symptoms can dramatically worsen. The virus attacks the lungs causing an accumulation of fluid that leads to severe coughing, shortness of breath and, in almost 40 percent of cases, death. While hantavirus infections, which are contracted from the urine and droppings of mice and rats carrying the microbe, are thankfully very rare, there is no vaccine and no cure. Investigations into the biology of the virus have now discovered a human protein called protocadherin-1 (labeled fluorescent green) that resides at the surface of lung cells (pictured) and is essential for virus entry. Indeed, lab animals genetically engineered to lack the protein were resistant to hantavirus infection. Understanding how this deadly microbe enters the body will thus give scientists essential insights on how to stop it.

Written by Ruth Williams

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    Солнечное затмение 14 декабря 2020 года  — полное  солнечное затмение  142  сароса , которое лучше всего будет видно в юго-восточной час...