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September 21 2016

Virtually unwrapped En-Gedi scroll

(W.B. Seales, C.S. Parker et al.  "From damage to discovery via virtual unwrapping: Reading the scroll from En-Gedi", Science Advances, DOI: 10.1126/sciadv.1601247, 21 Sep 2016)
Reposted byBlue-sing Blue-sing

September 12 2016


September 09 2016

Tags: science
Reposted byastronomygroup astronomygroup

September 05 2016

Philae found! (ESA, 5 Sept 2016)
Tags: science
Reposted byastronomygroupjalokim0riotKladderadatschyouambesensofiaspaketbugienordernzerocool911namelessczinok

August 26 2016

2171 fced 500

A High Stellar Velocity Dispersion and ~100 Globular Clusters for the Ultra Diffuse Galaxy Dragonfly 44
by Pieter van Dokkum, Roberto Abraham, et al.
http://arxiv.org/abs/1606.06291v1 (20 Jun 2016)

Recently a population of large, very low surface brightness, spheroidal galaxies was identified in the Coma cluster. The apparent survival of these Ultra Diffuse Galaxies (UDGs) in a rich cluster suggests that they have very high masses. Here we present the stellar kinematics of Dragonfly 44, one of the largest Coma UDGs, using a 33.5 hr integration with DEIMOS on the Keck II telescope. We find a velocity dispersion of 47 km/s, which implies a dynamical mass of M_dyn=0.7x10^10 M_sun within its deprojected half-light radius of r_1/2=4.6 kpc. The mass-to-light ratio is M/L=48 M_sun/L_sun, and the dark matter fraction is 98 percent within the half-light radius. The high mass of Dragonfly 44 is accompanied by a large globular cluster population. From deep Gemini imaging taken in 0.4" seeing we infer that Dragonfly 44 has 94 globular clusters, similar to the counts for other galaxies in this mass range. Our results add to other recent evidence that many UDGs are "failed" galaxies, with the sizes, dark matter content, and globular cluster systems of much more luminous objects. We estimate the total dark halo mass of Dragonfly 44 by comparing the amount of dark matter within r=4.6 kpc to enclosed mass profiles of NFW halos. The enclosed mass suggests a total mass of ~10^12 M_sun, similar to the mass of the Milky Way. The existence of nearly-dark objects with this mass was unexpected, as galaxy formation was thought to be maximally-efficient in this regime.

(Scientists Discover Massive Galaxy Made of 99.99 Percent Dark Matter)
Tags: science
Reposted bybesenbollabolla

August 25 2016

Joe Biden: "Peace For Our Time"
"The settlement of the Syrian problem, which has now been achieved is, in my view, only the prelude to a larger settlement in which all Near East may find peace. This morning I had another talk with the Turkish President, Herr Erdoğan, ... I believe it is peace for our time. We thank you from the bottom of our hearts. Go home and get a nice quiet sleep."

"America has been offered a choice between war and shame. She has chosen shame, and will get war." (Winston Churchill)
Tags: politics

August 12 2016


"The signal"
by "Pale Red Dot - A search for Earth-like planets around Proxima Centaury"

"So while we are convinced there is a signal in the Doppler measurements of Proxima, previous data do not allow to confirm its presence and clarify its origin. The long term variability of Proxima spoiled our attempts to combine data from previous observations so we needed a dedicated campaign. Combination of UVES and HARPS data at different cadences suggest that the star is showing a smoothly varying Doppler signal. Since the UVES survey set an upper limit between 2-3 Earth masses and if the signal is not activity induced, it must correspond to a planet smaller than that (between 1-2 Earth masses). The signal might well be caused by stellar activity, which should be quasi-periodic as opposed to the strict periodicity of the orbital motion of a putative planet. [...]"
Tags: science
Reposted byastronomygroupp856

August 11 2016

Leaving the EU...

Long-term persistence

by Luigi Guiso, Paola Sapienza, Luigi Zingales
Journal of the European Economic Association. doi:10.1111/jeea.12177 (Jul 2016)

We study whether a positive historical shock can generate long-term persistence in development. We show that Italian cities that achieved self-government in the Middle Ages have a higher level of civic capital today than similar cities in the same area that did not. The size of this effect increases with the length of the period of independence and its intensity. This effect persists even after accounting for the fact that cities did not become independent randomly. We conjecture that the Middle-Age experience of self-government fostered self-efficacy beliefs—beliefs in one's own ability to complete tasks and reach goals—and this positive attitude, transmitted across generations, enhances civic capital today. Consistently, we find that fifth-graders in former free city-states exhibit stronger self-efficacy beliefs and that these beliefs are correlated with a higher level of civic capital.
Tags: politics

August 10 2016

7955 9e60 500
Explaining disappearing stars... (KH 15D)
Tags: science

August 09 2016

"No object was presented during the final video. The silent videos precluded the use of false verbal suggestions, and participants were not asked leading questions about the objects. Nevertheless, 32% of participants reported having visual impressions of non-existent objects."

The Phantom Vanish Magic Trick: Investigating the Disappearance of a Non-existent Object in a Dynamic Scene
by Matthew L. Tompkins, Andy T. Woods, Anne M. Aimola Davies
Frontiers in Psychology, dx.doi.org/10.3389/fpsyg.2016.00950 (21 Jul 2016)
Tags: science

August 05 2016

2108 2d58 500
... approaching steadily (with minor course corrections Jan & Jul 2012) ...

KIC 8462852 Faded Throughout the Kepler Mission
by Benjamin T. Montet, Joshua D. Simon
http://arxiv.org/abs/1608.01316 (3 Aug 2016)

KIC 8462852 is a superficially ordinary main sequence F star for which Kepler detected an unusual series of brief dimming events. We obtain accurate relative photometry of KIC 8462852 from the Kepler full frame images, finding that the brightness of KIC 8462852 monotonically decreased over the four years it was observed by Kepler. Over the first ~1000 days, KIC 8462852 faded approximately linearly at a rate of 0.341 +/- 0.041 percent per year, for a total decline of 0.9%. KIC 8462852 then dimmed much more rapidly in the next ~200 days, with its flux dropping by more than 2%. For the final ~200 days of Kepler photometry the magnitude remained approximately constant, although the data are also consistent with the decline rate measured for the first 2.7 yr. Of a sample of 193 nearby comparison stars and 355 stars with similar stellar parameters, 0.6% change brightness at a rate as fast as 0.341 +/- 0.041 percent per year, and none exhibit either the rapid decline by >2% or the cumulative fading by 3% of KIC 8462852. We examine whether the rapid decline could be caused by a cloud of transiting circumstellar material, finding while such a cloud could evade detection in sub-mm observations, the transit ingress and duration cannot be explained by a simple cloud model. Moreover, this model cannot account for the observed longer-term dimming. No known or proposed stellar phenomena can fully explain all aspects of the observed light curve.
Tags: science

July 24 2016

"What the world’s oldest calculator tells us about the ancient Greeks' view of the universe", by Mike Edmunds, The Conversation, 20 July 2016
Reposted byastronomygroup astronomygroup

July 16 2016

"Sehr bezeichnend für seine Anlagen waren nun die Spiele des kleinen Albert. Meist waren es Geduldspiele, Laubsägearbeiten, Erstellung komplizierter Bauten mit dem bekannten Ankersteinbaukasten, am liebsten aber der Bau vielstöckiger Kartenhäuser, womit er seine Musse ausfüllte." Maja Winteler-Einstein, sister of Albert Einstein.

Anker-Steinbaukasten children's building blocks by F. Ad. Richter & Cie., Rudolstadt, [Germany], c.1880s
Provenance: The set has passed by direct descent from Albert Einstein to the present owner.

Christie's, London, Valuable Books And Manuscripts,
Price Realized: $83,000 (13 July 2016)
Tags: untagged
Reposted bysofias sofias

July 15 2016

"Soldiers: free / Turks: 1.75 Lira / Syrians: 3.00 Lira"
Tags: politics

July 13 2016


Tracking the will to attend: Cortical activity indexes self-generated, voluntary shifts of attention
by Leon Gmeindl, Yu-Chin Chiu, et al.
Attention, Perception, & Psychophysics, DOI: 10.3758/s13414-016-1159-7 (June 2016)

The neural substrates of volition have long tantalized philosophers and scientists. Over the past few decades, researchers have employed increasingly sophisticated technology to investigate this issue, but many studies have been limited considerably by their reliance on intrusive experimental procedures (e.g., abrupt instructional cues), measures of brain activity contaminated by overt behavior, or introspective self-report techniques of questionable validity. Here, we used multivoxel pattern time-course analysis of functional magnetic resonance imaging data to index voluntary, covert perceptual acts—shifts of visuospatial attention—in the absence of instructional cues, overt behavioral indices, and self-report. We found that these self-generated, voluntary attention shifts were time-locked to activity in the medial superior parietal lobule, supporting the hypothesis that this brain region is engaged in voluntary attentional reconfiguration. Self-generated attention shifts were also time-locked to activity in the basal ganglia, a novel finding that motivates further research into the role of the basal ganglia in acts of volition. Remarkably, prior to self-generated shifts of attention, we observed early and selective increases in the activation of medial frontal (dorsal anterior cingulate) and lateral prefrontal (right middle frontal gyrus) cortex—activity that likely reflects processing related to the intention or preparation to reorient attention. These findings, which extend recent evidence on freely chosen motor movements, suggest that dorsal anterior cingulate and lateral prefrontal cortices play key roles in both overt and covert acts of volition, and may constitute core components of a brain network underlying the will to attend.
Tags: science

July 04 2016

Allegory of science
by Moses Haughton the Elder, c. 1790
(Historical Portraits Image Library)
Tags: arts
Reposted bypaintingsgruetzeno-longer-kore

July 03 2016


June 30 2016

I see dead salmon...

Cluster failure: Why fMRI inferences for spatial extent have inflated false-positive rates
by Anders Eklund, Thomas E. Nichols, and Hans Knutsson
PNAS, doi:10.1073/pnas.1602413113 (28 Jun 2016)

Functional MRI (fMRI) is 25 years old, yet surprisingly its most common statistical methods have not been validated using real data. Here, we used resting-state fMRI data from 499 healthy controls to conduct 3 million task group analyses. Using this null data with different experimental designs, we estimate the incidence of significant results. In theory, we should find 5% false positives (for a significance threshold of 5%), but instead we found that the most common software packages for fMRI analysis (SPM, FSL, AFNI) can result in false-positive rates of up to 70%. These results question the validity of some 40,000 fMRI studies and may have a large impact on the interpretation of neuroimaging results.
Tags: science

June 29 2016

8370 dddb 500

Relative Likelihood for Life as a Function of Cosmic Time
by Abraham Loeb, Rafael A. Batista, David Sloan
http://arxiv.org/abs/1606.08448 (27 Jun 2016)

Is life most likely to emerge at the present cosmic time near a star like the Sun? We address this question by calculating the relative formation probability per unit time of habitable Earth-like planets within a fixed comoving volume of the Universe, dP(t)/dt, starting from the first stars and continuing to the distant cosmic future. We conservatively restrict our attention to the context of "life as we know it" and the standard cosmological model, LCDM. We find that unless habitability around low mass stars is suppressed, life is most likely to exist near 0.1 solar-mass stars ten trillion years from now . Spectroscopic searches for biosignatures in the atmospheres of transiting Earth-mass planets around low mass stars will determine whether present-day life is indeed premature or typical from a cosmic perspective.
Tags: science
Reposted byastronomygroupsoratadonaudampfschifffahrtsgesellschaftsofiasmariekneipemetafnordblubber

June 15 2016

Saturn's F ring fender bender (13 Jun 2016)
Tags: untagged
Reposted bylego-rojoMrHobbesastronomygroupRemulanerjalokim0anewryzmztarJonae
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