Daily Archives: 24 Jan 2021

Astronomy

Which Path Provides the Fastest Way To Circle the Central Black Hole? (Astronomy)

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Black-hole spacetimes are known to possess closed light rings. Shahar Hod and colleagues using compact theorem in their present work revealed that these unique null circular geodesics provide the fastest way, as measured by asymptotic observers, to circle around spinning Kerr black holes.

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Fermat’s principle, also known as the principle of least time, asserts that among all possible null trajectories, the path taken by a ray of light between two given points A and B in a flat spacetime geometry is the path that minimizes the traveling time TA→B. This remarkably elegant principle implies, in particular, that the unique null trajectory taken by a ray of light between two given points is generally distinct from the straight line trajectory which minimizes the spatial distance dAB between these points.

In the present work, Shahar Hod highlighted an intriguing and closely related physical phenomenon which characterizes curved spacetime geometries. In particular, they raise the physically interesting question: Among all possible closed paths that circle around a black hole in a curved spacetime, which path provides the fastest way, as measured by asymptotic observers, to circle the central black hole?

Their compact theorem has revealed the physically intriguing fact that the equatorial null circular geodesics (closed light rings), which characterize the curved black-hole spacetimes, provide the fastest way to circle around spinning Kerr black holes. In particular, they have explicitly proved that, in analogy with the Fermat principle in flat spacetime geometries, the unique curved trajectories r = rfast(M, a) [refer Eq. 1 given below]

Equation 1

which minimize the traveling times T of test particles around central black holes are distinct from the tangential trajectories r = r+(M, a) [refer Eq. (2) given below] which could minimize the traveling distances around the black holes.

Equation 2

“What we find most intriguing is the fact that the spin-dependent radii rfast(M, a) of the fastest circular trajectories, as given by the functional expression (1), exactly coincide with the corresponding radii rγ(M, a) of the null circular geodesics which characterize the spinning Kerr black-hole spacetimes. One therefore concludes that co-rotating null circular geodesics (closed light rings) provide the fastest way, as measured by asymptotic observers, to circle around generic Kerr black holes.”, told Shahar.

This research is supported by the Carmel Science Foundation.

Reference: Shahar Hod, Yael Oren, Arbel M. Ongo, Ayelet B. Lata, and Alona B. Tea, “Fermat’s principle in black-hole spacetimes”, International Journal of Modern Physics D, Vol. 27, No. 14, pp. 1-5, 1847025 (2021). https://www.worldscientific.com/doi/abs/10.1142/S0218271818470259?journalCode=ijmpd https://doi.org/10.1142/S0218271818470259

Copyright of this article totally belongs to our author S. Aman. One is allowed to reuse it only by giving proper credit either to him or to us.

Neuroscience

Memorize While You Sleep (Neuroscience)

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People think that the purpose of sleep is to rest the brain. But there is clear evidence that the brain is still busily at work during sleep, even when the brain is not dreaming.

No, I am not talking about “sleep learning,” where the idea is that you play recordings of information while you sleep. There is not much evidence that this works.

Did you know that your brain works while you sleep? Yes, both during dreaming and non-dreaming, your brain is consolidating memories of events in the immediately preceding day.

Most people think that the purpose of sleep is to rest the brain. But there is clear evidence that the brain is still busily at work during sleep, even when the brain is not dreaming. Decades ago, researchers demonstrated that many neurons fired just as much during sleep as during wakefulness. Some neurons were even more active during sleep.

One advantage that sleep provides for memory consolidation is that the brain doesn’t have all the distractions that occur during daytime wakefulness. Multiple-conflicting stimuli and tasks are very disruptive to memory consolidation.

The advantages offered by having fewer disruptive influences during sleep have also been confirmed in a study conducted in the brain imaging lab of Thomas Pollmacher in Munich, Germany. An auditory text stimulus was presented to sleep-deprived subjects prior to and after the onset of sleep, and imaging was performed to compare wakeful responses to sound stimuli with those during various stages of non-dreaming sleep. Brain activity during sleep was suppressed in auditory pathways and visual cortex, including other brain regions that are interconnected with the visual cortex. Suppression suggests that sleep shields the brain from the arousing effects of external stimulation that might disturb sleep. Blocking out such interference effects should facilitate memory consolidation. This study also prompted researchers to conclude that consolidation of memory occurs over many hours, at least in sleep-deprived subjects. That is to be expected, inasmuch as consolidation of memory depends on protein synthesis and physical changes in synapses.

Students often cut back on sleep to finish ever-mounting piles of homework and study. Combat soldiers are trained to function under sleep-deprived conditions. But these strategies are likely counter-productive. At my university, our Corps of Cadets used to have a tradition of rousing freshmen in the middle of the night and preventing them from sleeping. The idea was to make them tough. More likely, it just made them unable to do well in school, as I have seen many of them flunk out. Another area where this problem has surfaced is with sleep-deprived medical residents.

Sleep loss degrades many brain functions. In one study, sleep loss degraded visual vigilance and memory for words, and time-of-day fluctuations were found in choice reaction time, logical reasoning, and word memory. Exercise also seemed to have an effect in that brain function of non-exercising subjects degraded sooner than they did for exercising subjects. So, sleep-deprived couch potatoes beware!

Researchers have found that people who stay up all night after learning and practicing a new task show little improvement in their performance. No amount of sleep on following nights can make up for the toll taken by the initial all-nighter.

Robert Stickgold and colleagues at Harvard Medical School report that people who learned a particular task did not improve their performance when tested later the same day but did improve after a night of sleep. To see whether the night of sleep actually caused the improvement, Stickgold trained 24 subjects in the same visual discrimination task, which consisted of identifying the orientation of three diagonal bars flashed for a sixtieth of a second on the lower left quadrant of a computer screen full of horizontal stripes. Half of the subjects went to sleep that night, while the other half were kept awake until the second night of the study. Both groups were allowed to sleep on the second and third nights. On the fourth day, both groups were tested on the visual discrimination task. Those who slept the first night identified the correct orientation of the diagonal bars much more rapidly than they had the first day. The other group showed no improvement, despite the two nights of catch-up sleep.

Another compelling study for the role of sleep on memory consolidation was published by Sean Drummond and his colleagues at San Diego State University and the University of California, San Diego. They combined memory performance with magnetic resonance imaging (MRI) to study sleep deprivation effects on verbal learning of young, healthy adults. After a sleepless night, free recall fell by about half, and the brain imaging analysis showed reduced blood oxygen activity in the temporal area. However, the areas of the prefrontal cortex that had been activated during remembering after normal sleep worked even more after sleep deprivation. What’s more, the bilateral parietal lobes and two additional areas in the prefrontal cortex, usually not activated after normal sleep, became active.

What about a small degree of sleep loss? A University of Pennsylvania study showed even a little sleep loss can devastate memory. People were assigned to sleep regimens of four, six, or eight hours of sleep each night for two weeks and tested periodically during the daytime for mental performance. Subjects who got four or even six hours of sleep performed as poorly on brain function tests as they did when kept from sleeping at all for three consecutive days. So, short-changing your sleep each night by an hour or so builds up a sleep debt that affects attention and working memory. In the study, performance decline was cumulative. An interesting aside from the study was that none of the 48 people in the study realized that their mental performance had deteriorated from the mild sleep loss. As a college professor, I wonder about the performance loss going on in students who short-change their sleep for months at a time.

There are also studies revealing lack of sleep BEFORE learning interferes with memory. Formally, this is called “proactive interference,” because it occurs in advance. The cause may relate to what was just explained: a sleepy brain doesn’t think effectively.

In another study, 28 healthy young adults were divided into two groups. On the first day, one group was kept awake for 35 straight hours. Participants in the other group spent a normal sleep night at home. At 6 PM of the next day, all subjects watched a slide show of 150 slides of landscapes, objects, and people who weren’t celebrities. All subjects then were sent home to have a normal night’s sleep. The next evening all subjects took a pop quiz on the slides, which were randomly mixed with 75 new slides. The test was for subjects to recognize whether they had seen each slide before.

Those subjects who had been sleep deprived on the first night scored the lowest, even though they later had a night to catch up on lost sleep. The upshot of it all is that lack of sleep is bad for remembering, whether the sleep loss occurs before or after learning events. For those who wonder why humans need to sleep, one obvious benefit is to enhance learning.

Need to learn something quickly? Take a nap. Daytime naps are said to rejuvenate energy and lower stress. Now there is evidence that naps speed up consolidation of memories.

Matthew Walker reports experiments showing nap enhancement of memory. In his study, 39 young adults were divided into two groups. At noon, all the participants took part in a memory exercise that required them to remember faces and link them with names. Then the subjects took part in another memory exercise at 6 p.m., after 20 subjects had napped for 100 minutes during the break. Those who remained awake performed about 10 percent worse on the tests than those who napped. Students take note: 10% is often the difference between an A and a B.

References: (1) Drumond, Sean, Brown, Gregory, G., Gillin, J. Chrisstian, Stricker, John. L. (2000). Altered brain response to verbal learning following sleep deprivation. Nature 403(6770):655-7. DOI: 10.1038/35001068 (2) Stickgold, R., James, L, and Hobson, J. (2000) Nature Neuroscience. 3 (12), 1237-1238. DOI:10.1038/81756 (3) Van Dongen, H.P.A., Rogers, N.L. & Dinges, D.F. Sleep debt: Theoretical and empirical issues. Sleep Biol. Rhythms 1, 5–13 (2003). https://doi.org/10.1046/j.1446-9235.2003.00006.x (4) Walker, Matthew (2010). American Association for the Advancement of Science annual meeting presentation, San Diego, Feb. 21, 2010.o verbal learning following sleep deprivation. Nature 403(6770):655-7.

Copyright of this article totally belongs to our author William Klemm, who is a senior professor of Neuroscience at Texas A&M University. This article is republished here from psychology today under common creative licenses

Psychology

What to Say to Make the Most Memorable First Impression? (Psychology)

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Many people remember the words of others long after they met, even if they only met once. Words evoke emotion, which creates memories—for better or for worse. Positive memories of people based on the impact of their words can be powerful building blocks upon which to build relationships, both personal and professional. Whether you are looking for a new paramour or a new employer, thoughtfully pairing your words with positive emotion is a valuable investment in your future.

The Way You Make Me Feel

We all have friends, neighbors, or coworkers that we love to run into, not only because we anticipate positive conversation, but because of the way their face lights up with a smile when they see us, expressing authentically consistent interest in our lives. We also have people we would rather avoid—often because their negativity is similarly expressed both verbally and visually.

The sentiment has been attributed to the famous American poet and civil rights activist Maya Angelou as well as others, that people will forget what you said, but will remember how you made them feel. Personal experience corroborates this observation, as does research.

Stephanie S.A. Blom et al. in a piece aptly entitled “Perceiving Emotions in Visual Stimuli” (2020) recognized how social display of emotional facial expressions interaction can reveal the inner emotional states of interaction partners.[i] Among other findings, they recognized increasing levels of supporting contextual information as a way to increase the amount of emotion detection for words, but not facial expressions. They summarize their results as suggesting that the addition of emotionally relevant voice elements provides a method of positively influencing the detection of emotion.

This finding is significant in assessing potential social advantages through the appropriate combination of words and emotion. Blom et al. recognize the positive impact emotions can have on the processing of spoken words, citing the example of how reading aloud to young children positively impacts social-emotional development. We can imagine how many conversations in our own lives can be enhanced through pairing encouraging and inspiring words with contextually appropriate positive emotion. Authentic expressions of interest, respect, and admiration are memorable during a first meeting, as well as within established relationships. And apparently, according to other research, every word matters.

Words as Emotional Speech

Marisa G. Filipe et al. (2015), examined the impact of single words on perceived emotion.[ii] Filipe et al. define emotional prosody as referring to “the variation in acoustic cues such as fundamental frequency (F0), amplitude (or intensity), timing, and voice quality during speech that is used to convey the emotional meaning of an utterance.” Conducting their research in the Portuguese language, they investigated the impact of perceptual and acoustic characterization on the expression of liking and disliking. Using 30 study participants to identify vocal patterns as well as the intensity of expressed affect in single pre-recorded words, they found that participants consistently linked vocal profiles with perceived liking and disliking, finding intonation of liking intonation easier to recognize.

Although the authors recognize that additional research may clarify whether affect recognition and vocal cues may have different impacts across different languages, studies like this arguably highlight the significance of the interplay between emotion and words—even single words.

Words and Emotion

In light of research and experience, both empirical and anecdotal, we expect that words of encouragement and inspiration will be more memorable when they are accompanied by positive emotion. When you take advantage of this emotionally charged opportunity to authentically empower and inspire others, your audience is likely to remember not only how your words made them feel, but remember you—fondly.

References: [i] Blom, Stephanie S. A. H., Henk Aarts, and Gün R. Semin. 2020. “Perceiving Emotions in Visual Stimuli: Social Verbal Context Facilitates Emotion Detection of Words but Not of Faces.” Experimental Brain Research, November. doi:10.1007/s00221-020-05975-9. [ii] Filipe, Marisa G., Paulo Branco, Sónia Frota, São Luís Castro, and Selene G. Vicente. 2015. “Affective Prosody in European Portuguese: Perceptual and Acoustic Characterization of One-Word Utterances.” Speech Communication 67 (March): 58–64. doi:10.1016/j.specom.2014.09.007.

Copyright of this article totally belongs to Wendy L. Patrick who, is a career trial attorney, behavioral analyst, author of Red Flags, and co-author of Reading People. This article is republished here from psychology today under common creative licenses

Astronomy

Is it Possible To Obtain Cosmic Acceleration From Nothing, But Matter? (Astronomy)

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Summary:

◉ Recai Erdem and colleagues check the possibility of cosmic accelerated expansion by considering a case where matter is converted to radiation (or vice versa by particle physics processes).

◉ They found that cosmic accelerated expansion can be obtained in this way only if an intermediate state with negative equation of state forms during the conversion.

◉ They said it is difficult to obtain present cosmic accelerated expansion wholly through the usual particle physics interactions in this way since the localization scales of corresponding ρR’s for the usual particle physics processes are at the order of atomic scales i.e. at scales much smaller than the cosmological scales.

◉ Even when they have such an effect, these interactions will first accelerate the universe and then decelerate it in the time scale of the interaction time (which is smaller than ∼ 10^–8 sec), hence the net effect would be zero.

◉ Present cosmic accelerated expansion may be obtained in this way only if the life time of the resonance condensate has a cosmologically relevant time scale.

Observations showed that the universe is undergoing accelerated expansion at present, and many theoretical arguments and observational evidence suggest that the universe must have undergone an accelerated expansion period at the early times as well. Although the standard explanations for these accelerated expansions are cosmological constant at present era and inflationary models at early times there are many alternative ways; for example, quintessence, f(R) models, and gravitational particle production. However all these models have some problems. There is a problem associated with cosmological constant called the cosmological constant problem, and it seems that the best way may be the use of some symmetry to make it cancel and seek another method for late time cosmic acceleration. Inflationary models usually employ at least one new postulated scalar, and need special initial conditions, a similar situation (although less severe) is true for quintessence models.

f(R) type modified gravity models use an extension of general relativity, in gravitational particle production the energy density of the universe is an open thermodynamical system that is assumed to acquire energy from gravitational field while the question of if the universe is a closed system in this case is not clear enough. Therefore it is useful to seek the possibility of additional alternative ways for accelerated expansion. In particular, it would be desirable to have a model where the accelerated expansion is achieved with a minimal extension of the standard models of particle physics and cosmology. Recai Erdem and colleagues in their paper, in the light of the fact that, coupling an energy density to another one, modifies its equation of state, they seek if an energy density transfer due to elementary particle processes may have the potential of providing a source for cosmic accelerated expansion.

Although the analysis in their paper, in principle, is applicable to all types of particle physics processes, they specified it to the case of conversion of heavy particles to light particles i.e. to the conversion of matter to radiation. In fact there must be an era of the creation of matter and radiation not only because the ordinary matter and radiation must be produced anyway but also to have a well defined model that may serve at all eras of the universe. Moreover in the standard lore of cosmology the ordinary matter and radiation are assumed to be produced by the decays or the collisions of some other particles such as Higgs particle, curvaton etc. at early times. Particle physics processes ranging from high energies to atomic physics have an important role at present as well. Therefore the possibility of using just matter and radiation (as in this paper) interacting through the particle physics processes for cosmic acceleration with minimal need for exotic matter is interesting. The results of the following analysis shows that obtaining cosmic acceleration through conversion of matter to radiation (or vice versa) seems impossible except through formation of an intermediate state with negative equation of state (e.g. a QCD-like condensate formed by intermediate particles produced in the particle physics processes).

They considered the Robertson-Walker metric:

and for simplicity they take k = 0 which is in agreement with observations of Patrignani and colleagues. For the illustration of the method they considered a simple case; a universe that consists of matter and radiation. They assume that, at some time t1, the energy density of either of matter or radiation starts to be transferred to the other through some particle physics processes such as those given in Figure 1 below.

FIG. 1. The diagram on the left-hand side shows the decay of a particle with momentum p1 into two particles with momenta p2 and p3 e.g. the decay of a non-relativistic particle to two relativistic particles while the diagram on the right-hand side shows the (inelastic) collision of two particles with momenta p1 and p2 into two other particles with momenta p3 and p4 e.g. the collision of two non-relativistic particles into two relativistic particles through formation of an intermediate state

It seems difficult to obtain the present cosmic accelerated expansion wholly through the usual particle physics interactions in this way since the localization scales of corresponding ρR’s for the usual particle physics processes are at the order of atomic scales i.e. at scales much smaller than the cosmological scales. Even when they have such an effect, these interactions will first accelerate the universe and then decelerate it in the time scale of the interaction time (which is smaller than ∼ 10^–8 sec), hence the net effect would be zero.

– said Edrem.

This type of interactions may be relevant cosmologically only at early times (if they involve the usual particles) provided that a significant redshift takes place during their interaction time e.g. during the lifetime of the resonance particle. A very early time acceleration may be induced by fast out of equilibrium processes as those given in Figure 1 provided an intermediate state with ω < 0 forms. Present cosmic accelerated expansion may be obtained in this way only if the life time of the resonance condensate has a cosmologically relevant time scale.

Although they have considered such a toy model in this study, in order to entertain these possibilities in detail one needs to study different specific models in more detail along the lines given in this paper and confront it with observational data which is beyond the scope of this study that aims to seek the degree of possibility of obtaining the late time and the early time accelerated expansions of the universe in this way.

Specific models along these lines where different options for ρR and ρ'(t) / dt (where, ρ'(t) / dt is the rate of the energy density transfer from matter to radiation) are specified and their theoretical origins discussed and whose the results are confronted with observational data may be considered in future.

– Concluded authors of the study

Reference: Recai Erdem, “Is it possible to obtain cosmic accelerated expansion through energy transfer between different energy densities?,” Physics of the Dark Universe, Volume 15, 2017, Pages 57-71, ISSN 2212-6864,
https://doi.org/10.1016/j.dark.2016.12.001.
(http://www.sciencedirect.com/science/article/pii/S2212686416300711)

Copyright of this article totally belongs to our author S. Aman. One is allowed to reuse it only by giving proper credit either to him or to us.

Astronomy

A Challenge to Models of Star-formation Truncation in Massive Galaxies (Astronomy)

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The physical processes which suppress the growth of the stellar population in massive galaxies are not clear, although there is considerable agreement about the idea that the feedback winds from galaxies with active nuclei slow down their star formation. Now an international study published in Nature Astronomy, in which the Instituto de Astrofísica de Canarias (IAC) is a participant, suggests that the feedback winds do not have a direct impact on braking the formation of stars in massive galaxies, and attributes the process to other events such as ejection by huge tides caused when galaxies merge.

HST imaging and narrow and broad components ALMA maps of ID2299. The top-left panel shows the HST-F814W imaging of the source, sampling the UV rest-frame emission from young stars. The top (bottom) rows show the CO(2-1), CO(5-4), CI and CO(7-6) ALMA maps of the narrow (broad) emission. The luminosity of the broad line emission indicates that half of the total molecular gas mass is decoupled from the galaxy. © IAC

The rapid accumulation of matter by a supermassive black hole causes the emission of strong jets, winds, and radiation, which are expelled from the centre of the galaxy towards the exterior. Tnis phenomenon of feedback by Active Galactic Nuclei (AGN) has been thought of as a probable way for rapid braking of star formation, because the radiation emitted could eliminate the cold molecular gas clouds aroiund the nucleus which give birth to stars.

In addition, according to accepted theory, different models of galaxy evolution need the injection of energy from the AGN into the interstellar medium to explain the observed properties of massive galaxies, such as the phenomenology of star-formation truncation.

However, the study, in which over 15 scientific institutions have participated, warns about the scarce scientific evidence of cases of massive galaxies whose star formation was truncated abruptly due to feedback winds. In fact, using observations and simulations, the results show that the mechanism which brakes the formation of stars in those galaxies is not due to feedback winds,, but to other extreme mass ejections driven by mergers of galaxies.

The article also suggests that the activity of accretion by the central black holes occurs together with the formation of stars, and that these two phenomena self-regulate during thousands of millions of years. That means that the accretion onto the black holes, and the mechanisms driven by the feeback winds are slow processes, so that it is not likely that they cause the events which truncate star formation rapidly.

The observations are centred on ID2299, a typical galaxy whose star formation is about to switch off (and will remain like that for a long period of time) due to a violent event which has eliminated a major part of its interstellar medium.

“Our observations are tracing an extrem episode, which is unlikely to be consistent with the classical interpretation of a nuclear wind causing feedback” say those responsible for the study.

We don’t question that the feedback outflows play an important role. They are needed, for example, to explain the highest components of velocity in the spectra of galaxies with AGN” notes Shuowen Jin, a researcher at the IAC who has participated in the work. “However their importance may have been overestimated and it would be worth while reconsidering at least part of the literature about these outflows and their general impact on the evolution of the galaxies” adds this astrophysicist, and points out that “ in this study we have shown a new mechanism for the rapid cooling of galaxies: massive tidal ejections”

The difficulty of the work is due to the connection between phenomena on very different timescales and spatial scales, and this is where the IAC contribution comes in, by supplying photometry at multiple wavelengths, and also a catalogue of galaxies produced in 2018 and led by Jin, in which the authors estimated the numerical density of the disruptive events in the early universe.

For this an exhaustive analysis of data has been performed, most of them obtained directly from satellites, and from the Large Atacama Millimetre Array (ALMA) in Chile.

“We have also provided a very useful method for identifying weak residual emission lines, which is very important for a firm confirmation of the broader line of work in this study, and which is the key evidence for massive ejections” adds Shuowen Jin.

Reference: (1) Puglisi, A., Daddi, E., Brusa, M. et al. A titanic interstellar medium ejection from a massive starburst galaxy at redshift 1.4. Nat Astron (2021). https://doi.org/10.1038/s41550-020-01268-x. DOI: 10.1038/s41550-020-01268-x (2) Jin, Shuowen, Daddi, Emanuele et al., ““Super-deblended” Dust Emission in Galaxies. II. Far-IR to (Sub)millimeter Photometry and High-redshift Galaxy Candidates in the Full COSMOS Field”, Astrophysical Journal, 2018. https://ui.adsabs.harvard.edu/abs/2018ApJ.864.56J%2F/abstract (3) Jin, S. ; Daddi, E. ; Magdis, G. E. ; Liu, D. ; Schinnerer, E. ; Papadopoulos, P. P. ; Gu, Q. ; Gao, Y. ; Calabrò, A., “Discovery of Four Apparently Cold Dusty Galaxies at z = 3.62-5.85 in the COSMOS Field: Direct Evidence of Cosmic Microwave Background Impact on High-redshift Galaxy Observable”, Astrophysical Journal, 2019. https://ui.adsabs.harvard.edu/abs/2019ApJ.887.144J%2F/abstract

Provided by IAC

Archaeology

Blue and Lonesome – The Rarity of Blue Antelopes in Museum Collections (Archeology)

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Genetic research has shown that far fewer specimens of the blue antelope exist in museum collections than previously thought. An international team of scientist led by the Museum für Naturkunde Berlin and the University of Potsdam examined collection material of the extinct blue antelope. The study, published in Scientific Reports, demonstrates the potential of archival DNA to identify contentious specimens in museum collections. The genetic data is available to scientists globally.

The only mounted skin of a female blue antelope can be found in the Natural History Museum Vienna. Photo credit: NHM Vienna, Alice Schumacher

The blue antelope (Hippotragus leucophaeus) was an African antelope whose pelt was perceived to be bluish-grey. It is the only large African mammal species to have gone extinct in historical times. Its distribution might have already been limited when European colonists arrived in South Africa during the 17th century, and while they surely played a role, the exact reasons behind its decline are still being investigated. These range from overhunting to competition with livestock to fragmentation of migration routes.

The last blue antelope was shot in 1799/1800 about 34 years after it was described scientifically. Today only about 16 specimens are known from museum collections, of which several are taxonomically contentious. A team of scientists led by the Museum für Naturkunde Berlin and the University of Potsdam examined 10 of the 16 potential blue antelope specimens from 9 museum collections around the world in order to identify their species identity with certainty.

Only 4 of the 10 studied specimens turned out to actually belong to the blue antelope and not a single skull is among them. This renders the blue antelope one of the scarcest historical mammals in museum collections. It is, for example, far rarer than the famous Steller’s sea cow (more than 89 specimens) or the quagga, a subspecies of the plains zebra (~34 specimens).

The study illustrates clearly how archival DNA can be used to identify rare species in museum collections when comparative material is unavailable and diagnostic morphological features are unclear.

An analysis of the mitochondrial genomes shows a rather low maternal diversity in the blue antelope. This might confirm earlier hypotheses that the population size of the blue antelope was already low at the time of the European colonization of South Africa.

Reference: Elisabeth Hempel, Faysal Bibi et al., 2021 Identifying the true number of specimens of the extinct blue antelope (Hippotragus leucophaeus), DOI: www.nature.com/articles/s41598-020-80142-2

Provided by University of Potsdam

Astronomy

Massive Stellar Triples Leading to Sequential Binary Black Hole Mergers in the Field (Astronomy)

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The merger of two black holes in a binary system emits energy that can be detected on Earth by gravitational-wave observatories. The LIGO Scientific Collaboration and the VIRGO Collaboration have announced tens of confident detections of such mergers to date. Now, one of the main questions we can try to address concerns the origin of such merging binaries: do they come from isolated binary stars or from dense stellar environments? The answer might not be that simple.

A recent study published in the Astrophysical Journal Letters, led by OzGrav Alumni (Monash University) Dr. Alejandro Vigna-Gómez—and current DARK Fellow at the Niels Bohr Institute—shows that some binary black holes can originate from triple stellar systems. A triple stellar system consists of an inner binary and a triple stellar companion orbiting around it. If the inner binary is close enough, it can become a binary black hole which rapidly merges. The product of a binary black hole merger is a single rotating black hole. The merger of the inner binary black hole transforms the initial triple system to a binary, which itself might be able to merge within the age of the Universe. However, the assembly of these triple systems is not as simple as it sounds, as they need to be formed at low metallicities.

Time evolution of massive stellar triples: The figure illustrates compact stars in blue, standard evolving stars with red envelopes, black holes in black and merging binary black holes with a surrounding swirl. Black holes formed as sequential mergers are labeled “SM”. Top: the outer tertiary is the most massive star in the system and forms the first black hole in this triple. The inner binary needs to be constituted of compact stars and the tertiary can be either standard evolving or a compact star. Middle: all stars have similar masses. These triples can only lead to sequential mergers if all stars are compact. GW170729 might have experienced this evolution. Bottom: the tertiary is of significantly lower mass than either of the inner binary stars. This configuration does not lead to sequential mergers and is only presented for completion. Credit: T. Rebagliato & A. Vigna-Gomez.

Astronomers consider metals to be all elements except hydrogen and helium. Low metallicity environments are those in which hydrogen and helium compose more than approximately 99% of matter. Scientists believe that rare compact stars exist in low metallicity environments. In these environments, rapid rotation and mixing stir the stellar fuel and restrict chemically homogeneously-evolving stars from expanding. Additionally, metallicity increases alongside the age of the Universe, and therefore compact stars are more likely to be formed in the distant past.

Vigna-Gómez and collaborators studied the properties of such sequential binary black hole mergers and conclude that GW170729, one of the detected signals of a binary black hole merger, might be of triple stellar origin. The progenitor of GW170729 has at least one rapidly spinning black hole, plausibly from a previous merger.

Moreover, the masses are consistent with those of chemically homogeneously evolving stars, and the inferred formation time coincideswith the time it would take a triple system to experience two sequential mergers. Future observations from gravitational-wave observatories will help to further probe this formation channel and, more in general, understand the origin of binary black hole mergers.

Reference: Alejandro Vigna-Gómez, Silvia Toonen, Enrico Ramirez-Ruiz, Nathan W. C. Leigh, Jeff Riley, and Carl-Johan Haster, “Massive Stellar Triples Leading to Sequential Binary Black Hole Mergers in the Field”, The Astrophysical Journal Letters, Volume 907, Number 1, 2021. https://iopscience.iop.org/article/10.3847/2041-8213/abd5b7/meta

Provided by OzGrav

Psychology

An Attitude of Gratitude: Why Saying “I Am Grateful” Matters (Psychology)

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New research sheds light on how culturally embedded “attitudes of gratitude” can fortify optimism and resilience across a lifespan.

When it comes to “aging well,” a growing body of evidence suggests that optimism, gratitude, and positive self-perceptions of aging (SPA) may increase the odds of becoming one’s “hoped-for future self.“

For example, a recent study (Turner & Hooker, 2020) found that strongly identifying with a “hoped-for” future self (or a “feared” future self) may create a self-fulfilling prophecy that influences who we become as older adults. This Oregon State University research suggests that visualizing the person you want to be in old age (e.g., joyful and connected vs. bitter and isolated) could be predictive of who you become as a senior citizen.

Another recently published paper, “An Attitude of Gratitude: Older Japanese in the Hopeful Present,” by the University of Exeter’s Iza Kavedžija, unearths some time-tested ways that cultural traditions of “believing things will ‘somehow’ (nantonaku) work out well” combined with the regular use of phrases such as arigatai (“I am grateful”) and kansha helps older adults in Japan stay hopeful despite age-related challenges. Kansha means “gratitude,” “thanks,” or “appreciation” in Japanese.

This “attitude of gratitude” paper (Kavedžija, 2020) was published on December 14 in Anthropology and Aging. Kavedžija’s ethnographic Japan-based research focused on a cohort of people (age 80 and above) residing in one of South Osaka’s merchant neighborhoods called Shimoichi; these older adults remained hopeful, despite the challenges of aging.

Although these Japanese elders were in their 80s and 90s and had numerous concerns about the future, Kavedžija found that most cultivated what she calls “quiet hope” by sustaining a positive attitude rooted in kansha. “My argument is that gratitude as a mode of attunement offers the basis for what I have described as quiet hope,” she explains. Kavedžija also found that this “attitude of gratitude entwines the reflection on the past with an attention to the present moment in its fullness.”

Kavedžija’s years of ethnographic fieldwork with older inhabitants of two Osakan communities are thoroughly detailed in a book, Making Meaningful Lives: Tales from an Aging Japan (2019).

In response to the research question “What makes for a meaningful life?” Kavedžija posits that the ancient Japanese concept of ikigai (“that which makes life worth living”) holds many clues. Notably, the hopefulness that accompanies ikigai doesn’t require anything extraordinary. “Quiet hope is cultivated through practice, through many small everyday acts,” Kavedžija writes.

As an example, one of Kavedžija’s gratitude-prone interviewees exclaimed, “The sun came out! It’s so nice to walk. It is good to live in a place like this,” as she headed toward a public park where local friends enthusiastically greeted one another by saying, “How good that you came!” (kite hurehatta) in their Osakan dialect.

“During the course of my fieldwork—in which I particularly focused on those who were able to lead a good life despite the challenges presented to them, those who were able to maintain a sense of well-being and craft a sense of meaning in life—I noticed they appeared to express gratitude readily,” Kavedžija writes. “It may well be the case that their ability to emphasize gratitude as a positive orientation to the world allowed them a greater sense of well-being.”

“Feeling thankful and grateful for the care and support they have had during their life helps pensioners in the country to be more optimistic, even when they experienced difficulties and were anxious about getting older,” Kavedžija explained in a January 22 news release.

“An attitude of gratitude was embedded in older peoples’ recollections of the past, but also allowed them to think about the present in a hopeful way,” she added. “Gratitude in Japan can be seen to a large extent as a recognition of how much one relies on others as one moves through life. Gratitude highlights feelings of interdependence in the social world.”

Her fieldwork also showed that when people told stories about traumatic or challenging experiences they’d previously endured, the first-person storytelling narrative often concluded with the phrase benkyou ni narimashita, which means “I have learned from this” or “it was educational.” Framing adverse events as “learning experiences” you’re ultimately grateful to have encountered is a resilience-boosting way to flip the script. (See, “Post-Traumatic Growth and Post-Traumatic Stress Can Coexist.”)

Interestingly, Kavedžija found that the older adults she encountered during her fieldwork in Japan were reluctant to say “I’m happy” (even if they were in a good mood) but embraced saying “I am grateful” like a mantra. “They were reluctant to label themselves as happy, probably because, for their tastes, this would come too close to bragging,” she writes. “They were even disinclined to use the word “satisfied” (manzoku). ‘I would not go so far as to say I am satisfied,’ many told me. And yet, expressions of gratitude abounded.” She goes on to explain:

“This attitude of gratitude binds together both reflections on the past and attention to the present moment in its fullness. It also, I suggest, opens up space for a particular kind of hope, one grounded in the moment. Thus, the sense of a good and meaningful life that these elders conveyed encapsulates an attitude of gratitude as a way of inhabiting the present, rather than dwelling in the past or leaping toward the future.”

Kavedžija also observed that many customary and habitual aspects of Japanese vernacular require speakers to acknowledge the bidirectional flow of actions, goods, and favors.

As she explains, “I could simply say that I volunteered in the community salon in Shimoichi, or I might—as polite Japanese language would encourage me to do—state that I was ‘allowed to volunteer’ (borantia sasete itadakimashita), that I was given a chance to do so, as it were.” Kavedžija speculates that this type of phrasing “attunes the speaker to the role of others in our actions and de-emphasizes the sole agency of the individual.”

“Through appreciation, dependence on others is not seen as simply a burden or a potential source of embarrassment, but also as moving and deeply meaningful,” she concludes. “Meaningful relationships and encounters with others comprise a valuable foundation for what Japanese people call ikigai, or that which makes life worth living.”

References: (1) Iza Kavedžija. “An Attitude of Gratitude: Older Japanese in the Hopeful Present.” Anthropology & Aging (First published: December 14, 2020) DOI: 10.5195/aa.2020.244 (2) Shelbie G. Turner and Karen Hooker. “Are Thoughts About the Future Associated With Perceptions in the Present?: Optimism, Possible Selves, and Self-Perceptions of Aging.” The International Journal of Aging and Human Development (First published online: December 28, 2020) DOI: 10.1177/0091415020981883

Copyright of this article totally belongs to Christopher Bergland. This article is republished here from psychology today under common creative licenses

Psychology

Why Some People Don’t Seek Mental Health Services? (Psychology)

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A new study points to heightened concerns about stigma and one’s reputation.

Many of us know someone who is depressed or anxious yet reluctant to seek professional help. While every case is unique, a new study sheds light on the reasons why some individuals, often men, resist seeing a psychiatrist or counselor.

Several years ago, researchers at the University of Oklahoma uncovered a curious pattern. They discovered that American children with mental health needs were less likely to receive counseling or treatment if they lived in one of the so-called honor states (Brown, Imura, & Mayeux, 2014). Honor states are found in the South and Mountain West regions of the United States.

The researchers offered two plausible explanations for the curious pattern. First, parents in honor states may have ambivalent feelings about seeking psychological help. As a result, their emotionally distressed children are less likely to receive treatment. Second, honor states may offer fewer mental health services than non-honor states. Parents in honor states may want to get psychological help for their children, but they live in a state that has relatively few mental health clinics and counselors.

Why might people in honor states have ambivalent feelings about seeking psychological help? Some experts believe the answer can be found by examining cultural values.

Many people in the South and Mountain West regions have grown up in a culture of honor that values self-reliance, toughness, and a readiness to respond aggressively to personal affronts. They also can trace their lineage to ancestors, often in Scotland or Ireland, who lived as herders (Nisbett & Cohen, 1996).

Why is a culture of honor associated with a history of herding? In herding societies, a family’s wealth—a flock of sheep, for example—can be stolen overnight by a single thief. To safeguard their precarious livelihood, herding families established a reputation for toughness and self-sufficiency. They also developed a heightened sensitivity to social slights and demonstrated a willingness to use violence to punish someone who insulted them. “Don’t mess with me or my family. If you do, I will f*** you up.”

The ramifications of honor culture are manifold. Dueling to defend one’s honor was a common practice in the South, even after it disappeared in the North. Honor states have higher rates of domestic abuse and higher rates of homicide, especially honor-related killings. Every southern state has a “stand-your-ground” law that says a person can defend one’s self against threats or perceived threats, with lethal force if necessary, even if the person can retreat safely from the threatening situation.

With all this in mind, a team of researchers led by psychologist Stephen Foster at Penn State York University conducted a study to better understand why individuals living in honor states are less likely to use mental health services. They hypothesized that people who are motivated to maintain a reputation for toughness and self-reliance will be less likely to seek mental health services because they worry that others will see it as a sign of weakness (Foster, Carvallo, Lee, & Bernier, 2020).

The researchers recruited 156 students at a university in the southern United States. (Their sample was not large enough or diverse enough to be representative, but it was large enough to test the validity of a theory-based prediction.) The students completed questionnaires designed to measure four pertinent variables.

  1. Approval of honor concerns was indicated by agreement with statements such as “I think honor is one of the most important things I have as a human being” and “A real man is seen as tough in the eyes of his peers.”
  2. Concern for one’s reputation was indicated by agreement with statements such as “I often think about things I could do to enhance or maintain my reputation.”
  3. Stigma associated with seeking psychological help was indicated by agreement with statements such as “I would feel inadequate if I went to a therapist for psychological help” and “People will see a person in a less favorable way if they come to know that he/she has seen a psychologist.”
  4. Intention to seek psychological help was indicated by agreement with statements such as “I would be willing to set up an appointment with a psychological counselor in the future.”

Foster and his team discovered that, as a group, the students in their study who strongly endorsed honor concerns were less likely to say they would seek psychological help. They also determined, through statistical analyses, that the reason for this relationship could be traced to students’ concerns about maintaining their reputation and their belief that persons who seek psychological help are viewed less positively by others.

Putting it all together, a clearer picture emerges. People who grow up in honor states are especially concerned that their reputation for self-reliance and toughness will be damaged if they seek psychological help. The unfortunate consequence of this culture-based belief is an underutilization of mental health services in honor states.

Beliefs and values associated with a culture of honor are acquired effortlessly at a young age, with little or no explicit instruction. Such beliefs and values are often difficult to change. Nevertheless, public health officials would be well advised to consider the roles played by perceived stigma and concern for one’s reputation when thinking about ways to deliver mental health services to the individuals who need them.

References: (1) Brown, R. P., Imura, M., & Mayeux, L. (2014). Honor and the stigma of mental healthcare. Personality and Social Psychology Bulletin, 40(9), 1119-1131. (2) Foster, S., Carvallo, M., Lee, J., & Bernier, I. (2020). Honor and seeking mental health services: The roles of stigma and reputation concerns. Journal of Cross-Cultural Psychology, DOI: 10.1177/0022022120982070 (3) Nisbett, R. E., & Cohen, D. (1996). Culture of Honor: The Psychology of Violence in the South. Boulder, CO: Westview Press.

Copyright of this article totally belongs to Lawrence T. White, who, is Professor Emeritus of Psychology at Beloit College in Wisconsin. This article is republished here from psychology today under common creative licenses.