Dark Ages Research Articles

Relaxing CMB bounds on primordial black holes: The role of ionization fronts

The accretion of matter onto primordial black holes (PBHs) during the dark ages and the subsequent energy injection in the medium should have left imprints on the cosmic microwave background (CMB) anisotropies. Recent works have claimed stringent CMB limits on the PBH abundance, hardly compatible with a PBH interpretation of the gravitational-wave observations of binary BH mergers. By using a more realistic accretion model based on hydrodynamical simulations and conservative assumptions for the emission efficiency, we show that CMB limits on the PBH abundance are up to two orders of magnitude less stringent than previously estimated between $10$ and $10^4$ M$_\odot$. This reopens the possibility that PBHs might explain at the same time (at least a fraction of) the dark matter, some of the LIGO-Virgo-KAGRA binary BH mergers and the existence of super-massive BHs. More generally, we emphasize that PBH accretion can be a rather complex physical process with velocity dependences that are hard to assess, which introduces large uncertainties in accretion-based limits on the PBH abundance.

Geochemistry of a paleo-oxbow lake sediments and its implications for the late Holocene extreme overbank flooding history of the Yellow River within the Zoige Basin, NE Tibetan Plateau

Paleo-oxbow lake sediments can provide archives to reconstruct paleo-channel evolution and flooding history of the river. Multi-proxy approaches including detailed sediment stratigraphy, sedimentology and geochemistry have been implemented in a high-resolution sedimentary section of paleo-oxbow lake of the Yellow River within the Zoige Basin on the NE Tibetan Plateau, to reconstruct regional environmental changes and extreme overbank flooding history. Our results suggest that not only traditional sedimentological proxies, but also chemical elements can be applied in defining sequences with different genetic types, especially the paleoflood deposits in the paleo-oxbow profile. Two units of late-Holocence extreme overbank flooding deposits (OFDs) are identified in terms of the significantly higher proportions of sand, high contents of SiO2, Na2O, Ba, low contents of Al2O3, Fe2O3, MgO, K2O, Ti, Rb and high values of Zr/Fe, Zr/Rb ratios. These extraordinary flood events within the Zoige Basin were dated back to 2,960 ± 240–2,870 ± 270 a and 1840 ± 200–1700 ± 160 a, in response to the mid-Holocene climatic optimum to the late Holocene and the Dark Age Cold Period (DACP). And the strong rainfall caused by the abnormal atmospheric circulation during the period of climate transition and abrupt change may led to the frequent occurrence of extreme flood events in the source region of the Yellow River. These findings are important for understanding the response of regional fluvial system to high climatic instability and provide a new perspective for us to analyze the risk of flood disasters on the Tibetan Plateau under the background of climate change.

Editor’s Introduction to JPE Micro

Editor’s Introduction to <i>JPE Micro</i>

Cover Image Commentary—Shooting a Shot: The Decisive Moment of Abe Shinzo's and Asanuma Inejirō’s Assassinations on Camera

When Abe Shinzo 安倍晋三 (1955–2022), Japan's former prime minister, was shot from a short distance on July 8, 2022, the audience was stunned, shocked, and halted. Abe briefly turned back to where he heard the shots coming from before dropping to the floor. Mere seconds later, the murderer was caught with a homemade gun, his motivation not quite clear. The whole sequence took only a few seconds and was caught on multiple mobile phone cameras used in a mundane way to snap pictures of the local event by the audience who, looking toward Abe from various angles, unintentionally documented the shooting. The clips instantly became evidence of the crime committed, and were soon after posted on social media, broadcast on television, and shared with billions of viewers around the globe.Abe's assassination was not the first one in Japan's history to be caught on camera. The first was the killing of Asanuma Inejirō’ 浅沼稲次郎 (1898–1960), the leader of Japan's Socialist Party, who was murdered during a televised political debate on October 12, 1960.1 This infamous moment was caught on televised footage, as well as in a renowned image by Nagao Yasushi 長尾靖 (1930–2009), who won the 1961 World Press Photo of the Year2 and the 1961 Pulitzer Prize for that image (fig. 1).3What is so significant about the image of Asanuma's stabbing is the fact that it merges the crucial moment of photography (“the decisive moment,” as coined by Henri Cartier-Bresson [1952] in Images à la sauvette) and the instant of killing—the critical moment of death. Although the press announced the death later, the presence of this specific moment on camera is astonishing to viewers, as it displays the impossibility of the gaze to isolate this split second, while the camera is able to perfectly freeze, uniting together life and death at their point of convergence.In On Photography, Susan Sontag (1973: 10) has memorably discussed the closeness of photography and death, of photography and shooting: the photographer is “loading” the camera, then “aiming” through the viewfinder, till the focal point blends with the target; both the photographer and the assassin release the trigger (or shutter), which makes the process of taking pictures similar to the act of shooting. Yet, the result is not only the moment of death of the one who is shot, but the eternity of the photograph that documents that decisive moment. When the two coalesce, it is a stunning fraction of time.Although Nagao's image does not refer to a rifle or killing by gun, it contains the knifepoint at its center, and the picture is loaded with tension and coiled movement that predicts the looming death. For me, the spectacles dropping from Asanuma's nose and sitting diagonally across his face are the punctum of the image, foretelling his fall to come.In 2006, Morimura Yasumasa 森村泰昌 (b. 1951, Osaka) reenacted Asanuma's killings in two photographs, which are part of his Requiem for the 20th Century series. The reenactment consists of two frames: the reenactment of Nagao's photograph, in which Morimura performs as all men in the frame: the assassin, Asanuma himself, and the crowd (fig. 2, also the cover image for this issue); while the second image (fig. 3) is apparently a repetition of a frame taken from the footage of the stabbing shot in the TV studio where the political debate took place.The reenactment of a decisive moment is a tautological act: for Cartier-Bresson and those taking part in the language of photojournalism, the most important element is the immediacy, the liveness, and the punctual, decisive nature of the snap that is taken at an unrepeatable instant of time. Attempting to reenact this moment is an act of reexperiencing, reassessing, reevaluating the meaning of the political moment in particular, and the meaning of photography in general. Morimura's reenactment of these decisive moments through his shooting of the images is a reminder of the fragility of life and politics. In other words, the assassination of Abe Shinzō was experienced as a return into the past, a repetition of a dark age and practice that led Japan to darker moments of repression and totalitarianism in its history, exactly what makes it such a visceral, emotive experience.

Primordial non-Gaussianity and non-Gaussian covariance

In the pursuit of primordial non-Gaussianities, we hope to access smaller scales across larger comoving volumes. At low redshift, the search for primordial non-Gaussianities is hindered by gravitational collapse, to which we often associate a scale $k_{\rm NL}$. Beyond these scales, it will be hard to reconstruct the modes sensitive to the primordial distribution. When forecasting future constraints on the amplitude of primordial non-Gaussianity, $f_{\rm NL}$, off-diagonal components are usually neglected in the covariance because these are small compared to the diagonal. We show that the induced non-Gaussian off-diagonal components in the covariance degrade forecast constraints on primordial non-Gaussianity, even when all modes are well within what is usually considered the linear regime. As a testing ground, we examine the effects of these off-diagonal components on the constraining power of the matter bispectrum on $f_{\rm NL}$ as a function of $k_{\rm max}$ and redshift, confirming our results against N-body simulations out to redshift $z=10$. We then consider these effects on the hydrogen bispectrum as observed from a PUMA-like 21-cm intensity mapping survey at redshifts $2<z<6$ and show that not including off-diagonal covariance over-predicts the constraining power on $f_{\rm NL}$ by up to a factor of $5$. For future surveys targeting even higher redshifts, such as Cosmic Dawn and the Dark Ages, which are considered ultimate surveys for primordial non-Gaussianity, we predict that non-Gaussian covariance would severely limit prospects to constrain $f_{\rm NL}$ from the bispectrum.

Lunar far-side radio arrays: a preliminary site survey

Abstract The origin and evolution of structure in the Universe could be studied in the Dark Ages. The highly redshifted H i signal between 30 &amp;lt; z &amp;lt; 80 is the only observable signal from this era. Human radio interference and ionospheric effects limit Earth-based radio astronomy to frequencies &amp;gt;30 MHz. To observe the low-frequency window with research from compact steep spectrum sources, pulsars, and solar activity, a 200 km baseline lunar far-side radio interferometer has been much discussed. This paper conducts a preliminary site survey of potential far-side craters, which are few in number on the mountainous lunar far-side. Based on LRO LOLA data, 200 m resolution topographic maps of eight far-side sites were produced, and slope and roughness maps were derived from them. A figure of merit was created to determine the optimum site. Three sites are identified as promising. There is a need to protect these sites for astronomy.

In Defence Of Collegium System With A Caveat

This article undertakes a detailed examination of the arguments put forth on both sides of the debate and critically evaluates them in light of the fundamental principles of the country’s jurisprudence, constitutional morality, its seventy five years long experience as a democratic polity and its wider socio-cultural milieu. The Collegium System is not perfect, just like any other constitutional institution in our democratic set up, it plays an important role in ensuring the independence of judiciary. Despite its shortcomings, like democracy, it continues to be the best system amongst available alternatives. Truly, if the last bastion of independent judiciary falls, then the country would enter the “abyss of a new dark age”. What is the independence of the judiciary if independent and fearless judges are not being appointed?’ This article do recommendations for judicial reform with regard to the Collegium system. These include broadening the process of consultations for choosing meritorious judges by including consultations with the bar and other judges of the same court and taking into account principles of judicial federalism inculcated under article 124 of the constitution. It also recommends making the selection procedure faster, more efficient and inclusive by ensuring greater representation of women, Scheduled Caste and Schedule Tribes and other disadvantaged groups.

Tradition, Migration, and the Impact of Print: Local Rites of Seliḥot Recitation in Early Modern Ashkenaz

This article examines the history of the various rites of seli@hot (penitential prayers) recitation for what it can tell us about the changes the legacy of medieval Ashkenaz underwent in the early modern period. An eminently local matter by definition, these penitential liturgies were inevitably affected by the large-scale emigration of Jews from the German lands that marked the end of the Middle Ages. They were also subject to the trend toward standardization that came with the new technology of printing. While the local seli@hot rites were among the first Hebrew books to be printed in northern Italy, in Prague, and in Krakow, a similarly direct transition from practice into print was not an option in post-expulsion Germany. Hence, when Jewish communities began to revive in western Ashkenaz from the sixteenth century onward, local choices were predicated upon the availability of printed editions that had originated elsewhere, and the liturgical landscape changed accordingly. Nevertheless, even as the first seli@hot editions printed in Germany itself followed the Italo-Ashkenazic rite for the bulk of their corpus, they also preserve unacknowledged evidence of an indigenous rite well rooted in medieval tradition. Pockets of local tradition, it turns out, sometimes remained in place when rural Jews continued to uphold the rite of a historical region even after the urban community that had served as its center had ceased to exist. Liturgical sources are thus shown to shed unexpected light on Jewish life in sixteenth-century Germany, a dark age in German-Jewish history in more than one respect.

New Sources of the Text of the Life of Saint Pancratius of Tauromenia

The article is devoted to establishing the new sources of the text of the Life of St. Pancratius of Tauromenia. As a result of the analysis, several sources of its text were identified such as the novel “Leucippe and Clitophon” by Achilles Tatius (2nd century C. E.), autobiographical poems of St. Gregory of Nazianzus (late 4th century), the “Augustan History” (Historia Augusta, late 4th — early 5th century) and, separately, the writings of ancient historians for the legend of Taurus and Menia. In addition, parallels were found with the Syriac version of the “Acts of St. John” (5th century), which, perhaps, in some cases is closer to the Life than the Greek version of Pseudo-Prochorus. A special attention in the article is paid to the literary techniques and methods that are used by the author during his work with the sources of the Life. The sources considered in this article reveal the same methods described earlier in historiography, which the author of the Life uses when working with texts from other sources. The study carried out led to the conclusion that the author of the Life of St. Pancratius was an outstanding representative of the “dark ages” period of Byzantine literature (middle of the 7th — middle of the 9th centuries) and wrote for a “classically” educated audience or customer.

In search of nocturnal characters in eighteenth-century Lisbon

The history of Lisbon in the second half of the 18th century is marked by an unprecedented event : the 1755 earthquake that destroyed most of the city. After this catastrophe, the city began its reconstruction under Pombaline plans and – in the process – the city, during the day but mainly at night, was thrown back into a dark and dangerous age of criminality and mythical beliefs. This article aims to identify and describe the characters that (in fact or theory) inhabited the city by night, in a mixture of popular tales, superstition and real danger. Our research takes into account security at night, religious rituals and mythical beliefs in werewolves and witches. The historiographical frame is set by the work on the history of the night by Roger Ekirch (2005), Alain Cabantous (2009), Craig Koslofsky (2011), Brian D. Palmer (2000). Analysing and comparing the sources, it is possible to see how the night was a space of freedom and fear but was also becoming a social space.

The Idea of Democracy and Its Embodiment in the Middle Ages

In mass consciousness the dark Middle Ages is still represented as an epoch of undivided domination of monarchic regimes, whereas besides the well-known medieval city-states which inherited the traditions of antique democracy, in the Middle Ages there were many institutions where elements of democratic organization can be seen, especially if we understand democracy in an expanded sense, as a principle of power distribution in opposition to the concentration of power in one hand. Such elements can be seen in feudal liberties, in various forms of church institutions, in the election of heads of universal powers (popes and emperors), in the practice of political formations and city corporations, and finally in the theory of separation of powers, which in the Middle Ages prescribed a combination of powers, and was later elaborated by Montesquieu and other thinkers. Ultimately, many of these ideas have survived to our time and are embodied in today’s experience.

Jordan Peterson's Confusion over Religious Symbolism: A Lesson from Cain and Abel

AbstractJordan Peterson is a darling among conservatives and religious people alike. In defending religious belief as the only bulwark against a return to the dark ages, it becomes obvious that Peterson himself doesn't believe in what he preaches. People, he insists, should believe in the archetypal symbolism that is only revealed through a close reading of the Bible. If atheists would only read scripture with more sophistication they wouldn't so embarrassingly reject religion, and simultaneously threaten the very foundations of Western Civilization. It turns out that it's Peterson who comprehensively ignores symbolism. A simple Sunday school lesson shows this.

THE CONTRIBUTION OF MEDIEVAL MUSLIMS TO THE DEVELOPMENT OF MODERN SCIENCE: A REVIEW OF ALKHWARIZMI

Muslim scholars had reached the pinnacle of scientific culture for more than five centuries. There is no denying that it was the Muslim scholars of the day who shed light on the biological sciences of medieval Europe. If the Nobel Prize had been introduced at that time, only one Muslim would have won the Nobel Prize many times. Prominent mathematician Al Quarizmi has also received numerous awards. The purpose of this study is to identify the contributions of alKhwarizmi, one of the intellectuals of medieval Muslims, to the fields of astronomy, geography and mathematics. The study, which is based on characteristic descriptive methodology, analyzes secondary data such as research articles, texts, journals, and web articles related to the research topic. It is undeniable in today's modern world that medieval Muslim scholars brought the European Dark Ages to the light of knowledge and rose to its zenith. Muhammad ibn Musa alKhwarizmi who was a Persian geographer, trader, mathematician and the pioneer in the field of geography founded algebra in mathematics, algorithms, and algorithms. Hundreds of contributions to the introduction of Indian numerology to Europe and the field of commerce through his book, Arithmetic, further enrich his scholarly contributions. It is therefore irrefutable that his scholarly contributions became known as the results of this study and that his contributions of knowledge will still be talked about in future society.

Archiving Digital Archaeological Data - Evaluation of a Survey in Germany

Archiving of digital research data based on established standards and methods is an important part of the research data lifecycle. It guarantees the long-term transparency and reusability of research results. In the case of archaeological data, this is of particular importance for the preservation of unique and irreplaceable cultural heritage. To gain insight into the current state of affairs regarding long-term archiving in Germany, the SEADDA (Saving European Archaeology from the Digital Dark Age) COST Action (1) and the Commission on Archaeology and Information Systems in the Association of German State Archaeologists (2), with the support of the IANUS Research Data Center of the DAI (3), conducted a survey in spring/summer 2021. This article presents the results of the survey together with recommendations for further and supporting measures targeted at improving the long-term archiving of digital archaeological data in Germany.

CONTRIBUTIONS OF MUSLIMS AND ISLAM IN THE DEVELOPMENT OF MEDICAL SCIENCE

Muslims have played very important role in the field of medical science. They began experiments and observations from the first century of Hijra. Islam created great enthusiasm for scientific activities. After extensive translation from Greek, Sanskrit and some other ancient languages into Arabic, Islamic physicians had at their disposal nearly all the valuable medical works, like Hippocratic and Galenic writings. Islamic physicians were immensely influenced by them, and largely depended on their studies as they considered them medical authorities. One of the important physicians in Islam was Avicenna (980-1037) the king of medicine. He had a great influence in the West and the East and was regarded as a medical authority until the era of medical studies. It was used as textbook in the West and East. Another Muslim physician in Islam who had great influence on later Ottoman physicians was Ibn al Nafis. In the 14th century Mansoor bin Muhammad composed a monograph on anatomy called" Illustrated Anatomy " By the eighth century, most of Europe was deep in the dark ages, with only the Byzantine Empire preserving a few fragments of the ancient knowledge. Islamic Caliphate provided a stable environment for Islamic Scholars, who were sponsored by the ruling class. Most Islamic scholars were free to undertake pure research. As with the Ancient Greeks, the Islamic observations on life were closely tied to philosophy and theology. There are so many Muslim scholars who contributed a lot in the field of medical Science and will be discussed in my research paper

PRELIMINARY ANALYSIS OF THE MACROBOTANICAL REMAINS FROM THE LATE ANTIQUE AND BYZANTINE PHASES OF THE DOMUS AT POMPEIOPOLIS

Archaeological excavations of the Domus complex at Pompeiopolis reveal significant information about the evolution of the settlement beginning from its foundation in the second half of the 3rd c., its transformation through the Late Antiquity - Early Byzantine – Transition Period (Dark Ages) and the Middle Byzantine phase of the complex before its abandonment sometime after the 11th-12th c. In the 2021 excavation season, 32 flotation samples were processed representing the multi-period occupation of the domestic complex. In this paper, macrobotanical materials recovered from the flotation samples are analyzed. The results are discussed in relation to the sample contexts representing different phases of the Domus.

Observing Nulling of Primordial Correlations via the 21-cm Signal.

The 21-cm line emitted by neutral hydrogen (HI) during the Dark Ages carries imprints of pristine primordial correlations. In models of inflation driven by a single, canonical scalar field, we show that a phase of ultra-slow-roll can lead to a null in all the primordial correlations at a specific wave number k_{dip}. We consider scenarios wherein the null in the correlations occurs over wave numbers 1≲k_{dip}≲10 Mpc^{-1}, and examine the prospects of detecting such a damping in the HI signal due to the nulls at the level of power and bispectra in future observational missions.

Impact of radiation from primordial black holes on the 21-cm angular-power spectrum in the dark ages

We investigate the impact of radiation from primordial black holes (PBHs), in the mass range of ${10}^{15}\ensuremath{\lesssim}{M}_{\mathrm{PBH}}\ensuremath{\lesssim}{10}^{17}\text{ }\text{ }\mathrm{g}$ and ${10}^{2}\ensuremath{\lesssim}{M}_{\mathrm{PBH}}\ensuremath{\lesssim}{10}^{4}{M}_{\ensuremath{\bigodot}}$, on the 21-cm angular-power spectrum in the dark ages. PBHs in the former mass range affect the 21-cm angular-power spectrum through the evaporation known as Hawking radiation, while the radiation from the accretion process in the latter mass range. In the dark ages, radiation from PBHs can increase the ionization fraction and temperature of the intergalactic medium, change the global 21-cm differential brightness temperature and then affect the 21-cm angular-power spectrum. Taking into account the effects of PBHs, we find that in the dark ages, $30\ensuremath{\lesssim}z\ensuremath{\lesssim}100$, the amplitude of the 21-cm angular-power spectrum is decreased depending on the mass and mass fraction of PBHs. We also investigate the potential constraints on the mass fraction of PBHs in the form of dark matter for the future radio telescope in lunar orbit or on the far side surface of the Moon.

Moderne i suvremene predodžbe srednjovjekovlja – anakronija između bajke i horora

The paper reviews modern and contemporary images of the Middle Ages with emphasis on popular culture in the form of selected cases from literature, cinematography and video games in the context of the notion of historical anachronism. Erroneous statements that antedate or misplace events, objects or people basically constitute an “innocent” anachronistic transgression, which can be easily rectified using verifiable data. However, faulty projection of a set of features or characteristics to an age which did not know them represents a far more dangerous fallacy because it opens the question of interpretation – and interpretations vary. To understand past realities it is necessary to uncover how past people understood their own reality and why did they what they did. Projecting contemporary meanings onto the past, in this case the Middle Ages, is a genuinely perilous anachronism which is very difficult or even impossible to rectify. One example of such a historical “mistreatment” is the notion of the “Dark Ages”. Therefore, the paper traces the idea of the “Dark Ages” from the 14th century onward and considers the context in which it became quite widespread from the 18th and 19th centuries to the present day. However, the existence of a counter-myth in the form of the romantic idealization of the Middle Ages as a time of lost pre-modern innocence is also emphasized. The process of industrialization and modernization of (primarily English and Western) European societies in the 18th and 19th centuries and the enthronement of science and progress as leading social principles brought about an (only seemingly) unexpected consequence. Social change provoked nostalgia for an idealized and more simple pre-modern past which gave rise to the Gothic genre that introduced the (at that time socially subversive) element of “horror”. However, at the same time it engendered a romantic and nostalgic depiction of “olden times” which attracted a serious (mostly female) literary public. Even more important is the fact that the elements of the Gothic genre still exist in popular culture to this day through transmission into other popular culture venues, such as literature, cinematic and television content or video games. The extreme dual understanding of the Middle Ages between, metaphorically speaking, fairy tales and horror initially seems confusing, but in reality these images represent two opposite sides of the same coin. Finally, the paper seeks to answer the question of why the Middle Ages are imagined in the ways they are imagined, while notions about the Middle Ages are understood as an integral part of modern (secular) mythical discourse that legitimizes (post)modernity through the construction of extreme medieval otherness. Like it or not, the real or imagined medieval past is a recurrent and in some aspects even dominant feature of the (post)modern popular imagination. It would appear that it will remain so in the future, especially in the dynamic and newly developing post-COVID-19 world order.

Cambodia’s Decline and the Fall of Angkor as Pictured in the Chinese Sources during the Yuan and Early-Middle Ming dynasties (Late XIII - Early XV cc.)

The fall of Angkor in the 15th century marked a turning point in the Cambodian history leading to the downfall of the Khmer civilization and the start of the so-called “post-Angkor period” which is also often referred to as the “Dark Age of Cambodia”. Local epigraphical sources almost completely disappear from the 13th up to the 16th centuries while the Royal Chronicles dealing with this timeframe were compiled much later, mostly in the 18th and 19th centuries. Therefore, primary sources of this era are very scarce. While it is commonly accepted among the modern researchers that the fall of Angkor was a continuous process and was not a result of a single Siamese attack or a natural calamity (moreover, various reasons for this gradual downfall have been outlined), the perception of this process by other political powers in the region, especially China, has been significantly understudied. In this work the author made an attempt to trace the transformation of depiction of Cambodia in the Chinese sources of the Yuan and early Ming dynasties (both official and private).