ABSTRACT Analyzing curve-based crashes by neglecting underlying spatial relationships can lead to significant unobserved heterogeneity. A two-step latent class clustering framework was adopted to account for unobserved heterogeneity in crash severity on mountainous curves, incorporating curve design parameters and spatial relationships. An optimal number of clusters were determined followed by a swap-stepwise algorithm for selecting the most important contributors to the clustering process. Cluster-specific models were then developed using Firth’s logistic regression due to restricted sample size. Marginal effects revealed that while run-off-the-road and two wheelers invariably increased severity, cluster-specific effects showed that narrow and intermediately wide pavements increased crash severity by 13.77% and 11.45%, respectively, while dark conditions and age≥50 years reduced it by 14.53% and 12.44%, respectively. A very sharp approach curve with short length increased severity by 12.25%, reinforcing the role of spatial relationship. The findings can assist in designing and implementing more actionable safety interventions.

If our observable Universe is only a tiny region of a vastly larger and conformally older spacetime, then the usual formulations of the classical flatness and horizon problems of the Hot Big Bang can be reinterpreted as artifacts manifesting an observational selection effect; we occupy a small causal domain of a much larger causally-connected and possibly non-flat spacetime. A sufficiently large positive cosmological constant, Λ, sets the future asymptotic horizon scale of the observable Universe, ∼Λ−1/2, thereby implying that the observable Universe may simply be a minute patch of a far larger pre-existing one, hereafter a Small Patch Hypothesis. Importantly, this observational bound is purely geometric; regardless of when the Universe is observed, the maximum accessible scale is finite and fixed by Λ, independent of inflationary dynamics, anthropic arguments, or assumptions about the global hosting spacetime. The externally possibly frozen past-eternal state implied by a pre-existing, causally connected spacetime motivates, but does not strictly require, viewing the perturbation field as being in (or arbitrarily close to) a coarse-grained maximum-entropy—equilibrium—configuration. Conditionalizing only on fixed mean and variance, a Gaussian distribution uniquely emerges, while the absence of entropy gradients corresponds to adiabaticity. In this work these features are therefore treated as plausible maximum-ignorance priors for super-horizon perturbations, rather than as rigorously derived consequences of a fully developed microscopic notion of gravitational entropy. In this sense, inflation becomes one viable realization of the proposed Small Patch Hypothesis. Here, one particular non-inflationary alternative is considered for illustrative purposes in which a primordial spectrum Pζ(k) of the gauge-invariant perturbation ζ that pre-dates the Big Bang grows logarithmically toward large scales, k→0, and in fact diverges at some finite kc. If kc≪Λ−1/2, then our local cosmic patch probes only the regime where ζ≪1 and appears exceptionally smooth. Over the comparatively narrow observable window, this Pζ(k) mimics a slightly red-tilted, inflation-like spectrum. Rather than introducing high-energy new fields, this perspective frames large-scale homogeneity, isotropy, Gaussianity, adiabaticity, and the observed thermodynamic Arrow of Time as possible consequences of restricted observational access to a much larger Universe in equilibrium, rather than signatures of a unique early-Universe mechanism. Current observations cannot distinguish this logarithmically running spectrum from the standard power-law one, but future probes—for example high-resolution 21-cm measurements of the Dark Ages—may be able to falsify it.

Regulatory T Cells from Concept to Clinic: The 2025 Nobel Prize and Its Implications for Immune-Mediated Diseases and Cancer.

Currently the asteroid mass window (mass ∼ 1017- 1021 grams) remains unconstrained for Primordial Black Holes (PBHs) to make up all of the dark matter content of the universe. Given these PBHs have very small masses, their Hawking temperature can be up to hundreds of keV. This study investigates the potential impacts of PBH Hawking radiation on the intergalactic medium from z ∼ 800-25, namely studying the ionization history, kinetic gas temperature, and ultimately the 21 cm signature. We find that for masses on the low edge of the asteroid mass window, there are up two orders of magnitude increases in the ionization fraction and kinetic gas temperature by redshift 25, and the 21 cm spin temperature can differ from non-PBH cosmology by factors of a few. This analysis results in maximum differential brightness temperatures of +17 mK for our lightest PBH masses of 2.12 × 1016g. We also show maximal 53 mK discrepancies in differential brightness temperatures between our PBH and non-PBH cosmologies for our lightest PBH mass, while our heaviest PBH mass of 1.65 × 1017g shows only 0.5 mK variations. We find the Hawking-radiated electrons and positrons are instrumental in driving these IGM modifications. This study shows the necessity for a rigorous treatment of Hawking radiation in PBH cosmological observables from the dark ages through cosmic dawn.

Tracing inflationary imprints through the dark ages: Implications for early stars and galaxies formation

Abstract The Late Antique Migration period (LAMP; 300–700 CE) in what is today northeastern Germany was marked by significant socio-environmental shifts, including a decline in human activity, the abandonment of settlements, and a reduction in cereal cultivation, particularly of rye ( Secale cereale ). While these changes are well documented in pollen and archaeological records, the underlying drivers—whether socio-political instability, agricultural crises, or environmental pressures—remain debated.
Here, we use a multiproxy approach comprising high-resolution pollen data, archaeobotanical data, and climate reconstructions specific to the study area to explore the interplay between climatic fluctuations, agricultural practices, and human mobility during the LAMP. Although previous studies have examined socio-environmental changes during the Migration period using archaeological and palynological evidence, this study is the first to integrate these three proxies to systematically evaluate the role of climatic anomalies in shaping agricultural and demographic patterns.
We focus on the Dark Age Cold Period (DACP; 350–700 CE) and the Late Antique Little Ice Age (LALIA; 536–660 CE), which brought cold and wet conditions to northern Europe, likely disrupting agricultural productivity and fostering the spread of Claviceps purpurea (ergot), a fungus toxic to humans affecting cereal crops, particularly rye. Our findings suggest that these two climatic anomalies created favorable conditions for outbreaks of ergot, leading to agricultural instability and reduced food security, which, combined with socio-political pressures, contributed to the observed decline in human activity and settlement abandonment.
We suggest that climatic anomalies in the DACP and LALIA, coupled with the vulnerability of cereal crops to ergot infestation, influenced agricultural and demographic shifts in northeastern Germany. This paper not only refines our understanding of the DACP and the LALIA, but also demonstrates how climatic stressors and natural hazards can amplify socio-political vulnerabilities in pre-industrial societies.

Observations of the hydrogen hyperfine transition through the 21 cm line near the end of the cosmic dark ages provide unique opportunities to probe new physics. In this work, we investigate the potential of the sky-averaged 21 cm signal to constrain metastable particles produced in the early universe that decay at later times, thereby modifying the thermal and ionization history of the intergalactic medium. The study begins by extending previous analyses of decaying dark matter (DM), incorporating back-reaction effects and tightening photon decay constraints down to DM masses as low as 20.4 eV. The focus then shifts to non-minimal dark sectors with multiple interacting components. The analysis covers two key scenarios: a hybrid setup comprising a stable cold DM component alongside a metastable sub-component, and a two-component dark sector of nearly degenerate states with a metastable heavier partner. A general parameterization based on effective mass spectra and fractional densities allows for a model-independent study. The final part presents two explicit realizations: an axion-like particle coupled to photons, and pseudo-Dirac DM interacting via vector portals or electromagnetic dipoles. These scenarios illustrate how 21 cm cosmology can set leading bounds and probe otherwise inaccessible regions of parameter space.

Abstract The dark ages 21 cm signal is a promising probe of the currently unobserved infant Universe between the formation of the cosmic microwave background around z ≈ 1100 and the first galaxies around z ≈ 30. A detection of the signal will help researchers understand the nature of dark matter and dark energy, the expansion of the Universe, and any extensions to the concordance ΛCDM model that could explain the reported cosmic dawn 21 cm signal from EDGES and the Hubble tension. In this Letter we take existing constraints on the ΛCDM cosmological model from two early time probes, Planck and the Wilkinson Microwave Anisotropy Probe, and two late time probes, Dark Energy Survey galaxy lensing and clustering and baryon acoustic oscillations, and propagate these through to constraints on the magnitude of the dark ages 21 cm signal. We constrain the magnitude and central frequency of the signal while methodically accounting for uncertainties in the cosmological parameters. We find that within the context of our modeling assumptions and the ΛCDM paradigm, the depth of the dark ages 21 cm signal is known to better than 1 mK and the central frequency to within 0.05 MHz.

Abstract The Dark Ages (DA) provides a crucial window into the physics of the infant Universe, with the 21-cm signal offering the only direct probe for mapping out the three-dimensional distribution of matter at this epoch. To measure this cosmological signal, the Dark-ages EXplorer (DEX) has been proposed as a compact, grid-based radio array on the lunar farside. The minimal design consists of a 32 × 32 array of 3-m dipole antennas, operating in the 7 – 50 MHz band. A practical challenge on the lunar surface is that the antennas may get displaced from their intended positions due to deployment imprecisions and non-coplanarity arising from local surface undulations. We present, for the first time, an end-to-end simulation pipeline, called SPADE-21cm, that integrates a sky model with a DA 21-cm signal model simulated in the lunar frame and incorporating lunar topography data. We study the effects of both lateral (xy) and vertical (z) offsets on the two-dimensional power spectra across the 7 – 12 MHz and 30 – 35 MHz spectral windows, with tolerance thresholds derived only for the latter. Our results show that positional offsets bias the power spectrum by 10 – 30percnt relative to the expected 21-cm power spectrum during DA. Lateral offsets within σxy/λ ≲ 0.027 (at 32.5 MHz) keep the fraction of Fourier modes with strong contamination (> 50percnt of the signal) to less than 1percnt, whereas vertical height offsets affect a larger fraction. This conclusion holds for the 21-cm window with k∥ > 0.5 h cMpc−1 over the range of k⊥ = 0.003 − 0.009 h cMpc−1.

Currently, Indonesia has indeed built economicfacilities and infrastructure, but in fact these buildings are fragileand porous. Once the crisis wave hit the building, everything fellapart and it took a very long time to bring it back up. In fact, other Asial countries that have the same fate as Indonesia have already emerged from the economic crisis, such as Malaysia, Thailand, South Korea and others. In this context, the Islamic economic discourse is still very relevant to be discussed more seriously, and put forward as an alternative solution to overcoming the economic crisis in Indonesia, where the majorityof the population is Muslim. In fact, recently the banking worldhas adopted the Islamic economic system without a doubt. Conventional banks, for example, which have been based on theWestern economic system, are now starting to open banks basedon other money economy systems as well as developing anIslamic economic system. It seems that a fair system which formsthe basis of Islamic economics is the main reason why this systemis increasingly in demand and developed by the (Muslim) community today. Of course, the development of an Islamic economy will face many challenges today and in the future,and will serve as a test for whether the Islamic economy is able to overcome the economic crisis in Indonesia. Muslim economists are important pioneers who have successfully transformed the Islamic economic system into the modern world. Even to be honest, Western economists have actually learned from them. They appeared when the West was still in the dark ages. This includes their economy. Moreover, the emergence of this Muslimeconomy was in the post-Greek phase and pre-Western progress. However, the thoughts of these Muslim economists experiencedperiods of disconnection from generation to generation of Muslims recently. In fact, literature that discusses Islamic economics, especially the thoughts of Muslim economists, is stillvery rare and limited in the midst of the Indonesian Muslim community. The historical aspect is no exception. This study hasa very important meaning because it will trace the historical study of economic thought in Islam which is very unfavorable because, throughout Islamic history, Muslim thinkers and leaders have developed various economic ideas in such a way thatthey are not considered. The opposition comes from Schumpeter,great gap, by saying that the source of economics is from the west.

Abstract We introduce a Python package called ECHO21 for modelling the global 21-cm signal from the dark ages through cosmic dawn to the end of reionization. Leveraging its analytical framework, ECHO21 generates a single model in $\mathcal {O}(1)\,$s, allowing a large number of signals to be generated efficiently by distributing models across multiple cores. Thus, it is ideal for performing astrophysical or cosmological inference from a given 21-cm dataset. We offer six astrophysical parameters that control the Lyman-α (Lyα) emissivity, X-ray emissivity, emissivity of ionizing photons, and star formation rate. Beyond its efficiency some of the attractive and novel features in ECHO21 relative to previously published codes are inclusion of Lyα heating, ability to vary the standard cosmological parameters as easily as the astrophysical parameters, and different models of star formation rate density (physically-motivated, a semi-empirical, and an empirically-motivated). With a number of 21-cm experiments soon to provide cosmic dawn 21-cm data, ECHO21 is a flexible and extensible new open-source package for making quick but sufficiently realistic astrophysical inferences. We make our code publicly available.

The Ottoman Empire played a highly crucial role, especially in the expansion of Islamic territories and the development of Islamic civilization in Europe. The peak of Ottoman advancement occurred under the leadership of Sultan Suleiman I. He was known as al-Qanuni, meaning “the lawgiver,” because he successfully formulated laws to regulate society. During the Islamic golden age, many Europeans came to learn and seek knowledge from Muslims, enabling them to emerge from the Dark Ages. The Islamic world had once reached great heights in science, technology, and philosophy, particularly under the Abbasid Dynasty, which lasted from the 8th to the 15th century. This study uses library research with a historical approach. The results show that the Ottoman Empire achieved significant glory in its era, successfully expanding Islamic territories across three continents and managing the longest-lasting government in Islamic history (approximately seven centuries) involving 39 ruling leaders. However, the Ottoman government placed strong emphasis on military strength; the kingdom’s position would weaken if its military institutions were not well maintained, while a strong military contributed to the empire’s progress. Nevertheless, the military still played an important role in supporting the greatness of the Ottomans.

This article re-examines the Kalabhra period, spanning the 3rd to 6th centuries CE, which is generally considered a Dark Age in Tamil history. The article posits that the Kalabhra period was influential and significant for Tamil literature and, particularly, for musical arts. Several musical texts were produced during the Kalabhra era. Even the didactic literature (moral texts) of the post-Sangam period, which primarily aimed to teach virtue, contains verses that laud the art of music. This demonstrates that the Kalabhras cherished and protected musical arts. The article argues that historians manipulated data to suit their narrative, deliberately misrepresenting and distorting the Kalabhra period as a Dark Age. It contends that, in reality, this period might have only been a "Dark Age" for Shaivism (the Shaiva religion), and the overall branding of the Kalabhra period as a Dark Age was a deliberate attempt to conceal this specific decline. The purpose of this article is to establish, using the verses from the post-Sangam didactic texts as evidence, how art and literature, especially the art of music, flourished and thrived during the Kalabhra period.

English Coastal Archaeological Evidence of a Fifth-Century (Dark Ages) 4-Meter Sea-Level Rise in 70 Years, Portending a Similar Rise Imminently

This article examines the Renaissance as a period of revival of art, culture, and science in Europe from the 14th century to the modern era, which emerged after the collapse of the Western Roman Empire in 476 AD and the dominance of the church during the Dark Ages. The Renaissance, derived from the Latin "re" (again) and "naitre" (born), marked the transition to the modern era with a more humanistic and worldly Greco-Roman cultural inspiration, beginning in Italy such as Florence before spreading throughout Europe.

Stuck in the Dark Ages: Medieval Studies in the K–12 Classroom

The 1970s, Hyper-Masculinity, and the Dark Ages of Hockey

Book review of: Ian Milligan, Averting the Digital Dark Age: How Archivists, Librarians, and Technologists Built the Web a Memory (Johns Hopkins University Press, 2024), 230 pp., ISBN 9781421450131.

Putin’s Dark Ages: Political Neomedievalism and Re-Stalinization in Russia. By Dina Khapaeva.

This article considers how Alasdair MacIntyre’s Revolutionary Aristotelianism, given its foundations in Aristotle’s virtue ethics and Marxism, can strengthen critical social work (CSW) education, particularly in contesting the influence of liberalism. It was inspired by witnessing the transformative effect of centring learning activities around students’ values, which promoted both effective learning and a joyful learning community. This article suggests that three key elements of Revolutionary Aristotelianism explain that effect and can strengthen CSW education: the insistence that values are central to human action and thought; the assertion that such values can only become common values through shared labour; and the belief that human beings possess an inalienable agency. The final element may make the greatest contribution to CSW education, as in the face of the ‘new dark age’ introduced by neoliberalism, MacIntyre provides a logic of hope: that the capacity to transform our world exists and can be found in everyday practice.