Early Epochs Research Articles

Statistics for Galaxy Outflows at z ∼ 6–9 with Imaging and Spectroscopic Signatures Identified with JWST/NIRCam and NIRSpec Data

We present statistics of z ∼ 6–9 galaxy outflows indicated by spatially extended gas emission and broad lines. With a total of 61 spectroscopically confirmed galaxies at z ∼ 6–9 in the JWST CEERS, GLASS, and ERO data, we find four galaxies with [O iii] + Hβ ionized gas emission significantly extended beyond the kiloparsec-scale stellar components on the basis of the emission line images constructed by the subtraction of NIRCam broadband (line on/off-band) images. By comparison with low-z galaxies, the fraction of galaxies with spatially extended gas, 4/18, at z ∼ 6–9 is an order of magnitude higher than that at z ∼ 0–1, which can be explained by events triggered by frequent major mergers at high redshift. We also investigate medium- and high-resolution NIRSpec spectra of 30 galaxies at z ∼ 6–9, and identify five galaxies with broad (140−800 km s−1) lines in the [O iii] forbidden line emission, suggestive of galaxy outflows. One galaxy at z = 6.38 shows both spatially extended gas emission and the broad lines, while none of the galaxies with spatially extended gas emission or broad lines present a clear signature of active galactic nuclei (AGN) in either the line diagnostics or type 1 AGN line broadening (>1000 km s−1), which suggests that outflows are mainly driven by stellar feedback. The existence of galaxies with/without spatially extended gas emission or broad lines may be explained by different viewing angles toward outflows or the fact that these are galaxies in the early, late, or post phases of galaxy outflows at high redshift, where relatively large fractions of such galaxies indicate longer-duration and/or more frequent outflows at early cosmic epochs.

Food allergy prevention through the decades: An ounce of humility is worth a pound of cure.

Food allergy prevention has undergone a significant transformation over the past 3 decades. This review provides an overview of the evolution of food allergy prevention, highlighting changes in guidance, cost-effectiveness of prevention, the role of shared decision-making, and the emergence of oral immunotherapy for those in whom primary prevention fails. Changes to food allergy prevention over recent decades can be conceptualized into five epochs, which have followed a general trend of loosening restrictions on the allergen introduction timeline. These epochs are characterized by significant maternal and infant dietary restrictions in the "universal avoidance epoch"(-1990), loosened maternal diet restrictions in the "infant avoidance epoch" (1990-2000), a time-bound allergen introduction schedule in the "stratified avoidance epoch" (2000-2010), retraction of recommendations in the "corrective retraction epoch" (2010-2015), and endorsement of early allergen introduction in the "early introduction epoch" (2015-present), the start of which is marked by the 2015 Learning Early About Peanut study. In hindsight, it is clear that certain recommendations from previous decades were not the best course of action. A no-screening early introduction approach to food allergy prevention is both cost-effective and beneficial to patient quality of life.

Lithofacies, changes in mineral composition and reservoir properties of the Maykopian sediments in the Yevlakh-Aghjabedi Depression

Yevlakh-Aghjabadi depression is a well explored oil province located in the Middle Kura basin between Greater and Lesser Caucasus.The study investigates the lithofacial, mineralogical, and collector properties of the Maykopian sedimentary series within the Yevlakh-Aghjabadi depression, focusing on the Oligocene to Early Miocene epoch. Maykop deposits are widely distributed in the foothill regions of the Lesser Caucasus, both at the surface as natural outcrops and in the geological structure of deeper formations. In this article, in addition to core samples, the results of fieldworks have also been widely discussed. The conducted research indicates favorable paleogeographic conditions for oil and gas presence in these depressions. The sedimentary sequence, up to 2200 meters thick, is divided into Lower and Upper Maykopian subgroups, showing fluctuating thickness distribution. The primary source of clastic materials for the Maykopian suit is the Lesser Caucasus Mountain range. The lithological composition consists of clay, sandstones, and conglomerates, influenced by paleogeographic changes and paleochannels. Collector properties vary, with Lower Maykopian sediments exhibiting better characteristics, especially in the south-western part of the basin. The mineralogical composition dominated by fine-grained feldspars, impacts reservoir quality. Maykopian suits in the oil and gas regions of Ganja and Muradkhanli, which encompass the southernwestern and northern-eastern flanks of the Yevlakh-Aghjabedibasin, as well as conducting extensive research on reservoir properties, will enable the proper direction of future exploration activities. For this purpose, the overall condition of the Maykopian suits and the distribution of lithofacies have been analyzed, and the characteristics of hydrocarbon reservoirs have been determined. Keywords: lithology; lithofacies; Maykopian; sandy and clayey sediments; argillaceous sandstones; porosity; permeability.

Dynamical modelling and the origin of gas turbulence in z ∼ 4.5 galaxies

Context. In recent years, a growing number of regularly rotating galaxy discs have been found at z ≥ 4. Such systems provide us with the unique opportunity to study the properties of dark matter (DM) halos at these early epochs, the turbulence within the interstellar medium and the evolution of scaling relations. Aims. Here, we investigate the dynamics of four gas discs in galaxies at z ∼ 4.5 observed with ALMA in the [CII] 158 μm fine-structure line. We aim to derive the structural properties of the gas, stars and DM halos of the galaxies and to study the mechanisms driving the turbulence in high-z discs. Methods. We decomposed the rotation curves into baryonic and DM components within the extent of the [CII] discs, that is, 3 to 5 kpc. Furthermore, we used the gas velocity dispersion profiles as a diagnostic tool in investigating the mechanisms driving the turbulence in the discs. Results. We obtain total stellar, gas and DM masses in the ranges of log(M/M⊙) = 10.3 − 11.0, 9.8 − 11.3, and 11.2 − 13.3, respectively. We find dynamical evidence in all four galaxies for the presence of compact stellar components conceivably, stellar bulges. The turbulence present in the galaxies appears to be primarily driven by stellar feedback, negating the necessity for large-scale gravitational instabilities. Finally, we investigate the position of our galaxies in the context of local scaling relations, in particular the stellar-to-halo mass and Tully–Fisher analogue relations.

Imaging of I Zw 18 by JWST. I. Detecting Dusty Stellar Populations

We present a JWST imaging survey of I Zw 18, the archetypal extremely metal-poor, star-forming (SF), blue compact dwarf galaxy. With an oxygen abundance of only ∼3% Z ⊙, it is among the lowest-metallicity systems known in the local Universe, and is, therefore, an excellent accessible analog for the galactic building blocks which existed at early epochs of ionization and star formation. These JWST data provide a comprehensive infrared (IR) view of I Zw 18 with eight filters utilizing both Near Infrared Camera (F115W, F200W, F356W, and F444W) and Mid-Infrared Instrument (F770W, F1000W, F1500W, and F1800W) photometry, which we have used to identify key stellar populations that are bright in the near- and mid-IR. These data allow for a better understanding of the origins of dust and dust-production mechanisms in metal-poor environments by characterizing the population of massive, evolved stars in the red supergiant (RSG) and asymptotic giant branch (AGB) phases. In addition, it enables the identification of the brightest dust-enshrouded young stellar objects (YSOs), which provide insight into the formation of massive stars at extremely low metallicities typical of the very early Universe. This paper provides an overview of the observational strategy and data processing, and presents first science results, including identifications of dusty AGB, RSG, and bright YSO candidates. These first results assess the scientific quality of JWST data and provide a guide for obtaining and interpreting future observations of the dusty and evolved stars inhabiting compact dwarf SF galaxies in the local Universe.

The ALPINE-ALMA [CII] survey: Dust emission effective radius up to 3 kpc in the early Universe

Aims. Measurements of the size of dust continuum emission are an important tool for constraining the spatial extent of star formation, and hence the buildup of stellar mass. Compact dust emission has generally been observed at cosmic noon (z ∼ 2 − 3). However, at earlier epochs, toward the end of the reionization (z ∼ 4 − 6), only the sizes of a handful of infrared (IR) bright galaxies have been measured. In this work, we derive the dust emission sizes of main-sequence (MS) galaxies at z ∼ 5 from the ALPINE survey. Methods. We measured the dust effective radius, re, FIR, in the uv-plane in Band 7 of ALMA for seven ALPINE galaxies with resolved emission and we compared it with rest-frame ultraviolet (UV) and [CII]158 μm measurements. We studied the re, FIR − LIR scaling relation by considering our dust size measurements and all the data in the literature at z ∼ 4 − 6. Finally, we compared our size measurements with predictions from simulations. Results. The dust emission in the selected ALPINE galaxies is rather extended (re, FIR ∼ 1.5 − 3 kpc), similar to [CII]158 μm but a factor of ∼2 larger than the rest-frame UV emission. Putting together all the measurements at z ∼ 5, spanning two decades in luminosity from LIR ∼ 1011 L⊙ to LIR ∼ 1013 L⊙, the data highlight a steeply increasing trend of the re, FIR − LIR relation at LIR < 1012 L⊙, followed by a downturn and a decreasing trend at brighter luminosities. Finally, simulations that extend up to the stellar masses of the ALPINE galaxies considered in the present work predict a subset of galaxies (∼25% at 1010 M⊙ < M⋆ < 1011 M⊙) with sizes as large as those measured.

Gravitational wave signals from early matter domination: interpolating between fast and slow transitions

An epoch of matter domination in the early universe can enhance the primordial stochastic gravitational wave signal, potentially making it detectable to upcoming gravitational wave experiments. However, the resulting gravitational wave signal is quite sensitive to the end of the early matter-dominated epoch. If matter domination ends gradually, a cancellation results in an extremely suppressed signal, while in the limit of an instantaneous transition, there is a resonant-like enhancement. The end of the matter dominated epoch cannot be instantaneous, however, and previous analyses have used a Gaussian smoothing technique to account for this, and consider only a limited regime around the fast transition limit. In this work, we present a study of the enhanced gravitational wave signal from early matter domination without making either approximation and show how the signal smoothly evolves from the strongly suppressed to strongly enhanced regimes.

Mеsozoic Tectonothermal Evolution of the Zagan Metamorphic Core Complex in Western Transbaikalia: 40Ar/39Ar and FTA Dating

Abstract A model of tectonothermal evolution of the Zagan metamorphic core complex (MCC) based on the new data from 40Ar/39Ar dating of amphibole, mica, and apatite fission-track dating is discussed. A relationship with the long-range impact of processes from the collision of the North China (Amurian–North China) block with the Siberian continent in the Mesozoic era is proposed. The Zagan MСС was formed in the Cretaceous period on the southern flank of a high mountain uplift of Western Transbaikalia, composed of late Paleozoic granitoids of the Angara–Vitim batholith. According to 40Ar/39Ar dating of amphiboles and micas from the mylonite zone, the active development time of the Zagan MCC corresponds to the early Cretaceous epoch (131, 114 Ma). The tectonic exposure of the core from about 15 km to the depths of about 10 km occurred at a rate of tectonic erosion of 0.4–0.3 mm/year as a result of post-collisional extension of the Mongol–Okhotsk orogen. Apatite fission-track dating shows that further exhumation and cooling of the rocks to about 3 km occurred in the lower-upper Cretaceous epoch (112, 87 Ma). The erosional denudation rate was about 0.3 mm/year.MCC- metamorphic core complexes, AFT- apatite fission-track

EPOCHS Paper V. The dependence of galaxy formation on galaxy structure at z < 7 from JWST observations

ABSTRACT We measure the broad impact of galaxy structure on galaxy formation by examining the ongoing star formation and integrated star formation history as revealed through the stellar masses of galaxies at z < 7 based on JWST CEERS data from the Extended Groth Strip (EGS). Using the morphological catalog of 3965 visually classified JWST galaxies from Ferreira et al. (2023), we investigate the evolution of stars, and when they form, as a function of morphological type as well as galaxies classified as passive and starburst through spectral energy distributions. Although disc galaxies dominate the structures of galaxies at z < 7, we find that these discs are in general either ‘passive’, or on the main sequence of star formation, and do not contain a large population of starburst galaxies. We also find no significant correlation between morphological type and the star formation rate or colours of galaxies at z < 7. In fact, we find that the morphologically classified ‘spheroids’ tend to be blue and are not found to be predominately passive systems at z > 1.5. We also find that the stellar mass function for disc galaxies does not evolve significantly during this time, whereas other galaxy types, such as the peculiar population, evolve dramatically, declining at lower redshifts. This indicates that massive peculiars are more common at higher redshifts. We further find that up to z ∼ 7, the specific star formation rate (sSFR) does not vary with visual morphology, but strongly depends on stellar mass and internal galaxy mass density. This demonstrates that at early epochs galaxy assembly is a mass-driven, rather than a morphologically driven process. Quenching of star formation is therefore a mass-dominated process throughout the universe’s history, likely due to the presence of supermassive black holes.

Galaxy morphology from z ∼ 6 through the lens of JWST

Context. The James Webb Space Telescope’s (JWST’s) unprecedented combination of sensitivity, spatial resolution, and infrared coverage has enabled a new era of galaxy morphology exploration across most of cosmic history. Aims. We analyze the near-infrared (NIR ∼ 0.8 − 1 μm) rest-frame morphologies of galaxies with log M*/M⊙ > 9 in the redshift range of 0 < z < 6, compare with previous HST-based results and release the first JWST-based morphological catalog of ∼20 000 galaxies in the CEERS survey. Methods. We classified the galaxies in our sample into four main broad classes: spheroid, disk+spheroid, disk, and disturbed, based on imaging with four filters: F150W, F200W, F356W, and F444W. We used convolutional neural networks (CNNs) trained on HST/WFC3 labeled images and domain-adapted to JWST/NIRCam. Results. We find that ∼90% and ∼75% of galaxies at z < 3 have the same early and late and regular and irregular classification, respectively, in JWST and HST imaging when considering similar wavelengths. For small (large) and faint objects, JWST-based classifications tend to systematically present less bulge-dominated systems (peculiar galaxies) than HST-based ones, but the impact on the reported evolution of morphological fractions is less than ∼10%. Using JWST-based morphologies at the same rest-frame wavelength (∼0.8 − 1 μm), we confirm an increase in peculiar galaxies and a decrease in bulge-dominated galaxies with redshift, as reported in previous HST-based works, suggesting that the stellar mass distribution, in addition to light distribution, is more disturbed in the early Universe. However, we find that undisturbed disk-like systems already dominate the high-mass end of the late-type galaxy population (log M*/M⊙ > 10.5) at z ∼ 5, and bulge-dominated galaxies also exist at these early epochs, confirming a rich and evolved morphological diversity of galaxies ∼1 Gyr after the Big Bang. Finally, we find that the morphology-quenching relation is already in place for massive galaxies at z > 3, with massive quiescent galaxies (log M*/M⊙ > 10.5) being predominantly bulge-dominated.

Untangling the dynamics of heavy rainfall events (HRE) in the Northeast monsoon season and exploring its connection to the Indian Ocean warming and the Madden Julian Oscillation

Southeastern Peninsular India witnessed heavy rainfall events (HRE) during the recent El Nino year 2015 and La Nina year 2021 in November and early December. Both these events were associated with enhanced easterly wave activity and active Madden Julian Oscillation (MJO) over the Maritime continent. The MJO was on the fourth (MJO-4) phase for 15 and 17 days in November 2015 and 2021 respectively. A weakening in the positive correlation between El Nino and Northeast monsoon rainfall and a strengthening in the positive correlation between the MJO-4 days and HRE is observed in very recent years. This study revealed that the unequal changes in Sea Surface Temperature (SST) in the Indo-Pacific region i.e., warming over the eastern Indian Ocean (IO) and cooling over the western Pacific Ocean can be favourable for the increased occurrence of MJO-4 days as well as HRE over southern Peninsular India. The easterly wind anomalies towards the southern Bay of Bengal (BoB) and southeastern Peninsular India and westerly wind anomalies over the central equatorial Indian Ocean are significantly correlated with HRE in the recent epoch (2001−2021). Warming in eastern IO brings easterlies from the cool western Pacific and westerlies from the western IO, which helps the MJO to remain active over maritime continent and inhibits its further eastward propagation. The HREs in the recent epoch are associated with the low-pressure systems and cyclonic circulation over southern Peninsular India, in which moisture transport is from the Arabian Sea to Peninsular India. The HRE in the early epoch (1981–2000) is related to the anticyclonic circulation over BoB region and the moisture transport is from BoB and southeastern IO. A proposed mechanism for the HRE in the recent epoch is as follows. The SST gradient in the Indo-Pacific Ocean is conducive for the moistening of MJO-4 region and is favourable for the enhanced easterly wave activity and the formation of low-pressure systems, which get strengthened while moving towards southern Peninsular India due to the presence of strong equatorial westerlies over IO. These strengthened low pressure systems leads to strong ascending wind anomalies over southern Peninsular India and strong descending anomalies over Central IO and HREs over southern Peninsular India.

The youngest of hot jupiters in action: episodic accretion outbursts in Gaia20eae

ABSTRACT Recent imaging observations with ALMA and other telescopes found widespread signatures of planet presence in protoplanetary discs at tens of au separations from their host stars. Here we point out that the presence of very massive planets at 0.1 au sized orbits can be deduced for protostars accreting gas at very high rates, when their discs display powerful Thermal Instability (TI) bursts. Earlier work showed that a massive planet modifies the nature of this instability, with outbursts triggered at the outer edge of the deep gap opened by the planet. We present simulations of this effect, finding two types of TI outbursts: downstream and upstream of the planet, which may or may not be causally connected. We apply our model to the outburst in Gaia20eae. We find that the agreement between the data and our disc TI model is improved if there is a planet of six Jupiter masses orbiting the star at 0.062 au separation. Gaia20eae thus becomes the second episodically erupting star, after FU Ori, where the presence of a massive planet is strongly suspected. Future observations of similar systems will constrain the mode and the frequency of planet formation in such an early epoch.

The Shell of the Cosmos

The Big Bang theory, widely accepted by cosmologists, explains the origin, expansion, and eventual fate of the universe. It was further developed by inflation theory, which solves issues like the horizon and flatness problems. This theory states that the Cosmic Microwave Background (CMB), a remnant of the Big Bang, permeates the entire universe. Cosmologists believe these photons were emitted during the recombination epoch, approximately 380,000 years after the Big Bang when the cosmos had a temperature of around 3,000 Kelvin. Additionally, the Lambda-Cold Dark Matter (ΛCDM) model addresses questions arising from observations of the cosmos, such as the existence of light elements like hydrogen, helium, lithium, and the anisotropy in the CMB, and eventually, the continuous expansion of space. In this model, dark energy, represented as the cosmological constant lambda (Λ), exerts negative pressure on empty space, counteracting the effects of gravity with a repulsive force. While the Standard Model of Particle Physics (SMPP) posits that the universe's matter originated from fundamental particles (quarks and leptons), it cannot explain the origin of these particles and how they came into existence, because general relativity and the SMPP cannot be integrated to explain matter production at the singularity point. T-Consciousness Cosmology introduces the ‘Spherical Cosmos Model’ (SCM) to answer questions about the cause of the explosion, expansion, and shape of the universe, the nature of ordinary matter and energy, dark matter and energy, the fate of the universe, the reason for the high density of objects in the depths of space, etc. In this model, the spherical cosmos has a shell called the ‘Shell of the Cosmos,’ made of Taheri Absolute Matter (TAM) that not only isolates it but also produces dark matter and dark energy, ordinary matter and ordinary energy, and finally space mesh from the inner surface to the inside of the cosmos since the birth of the universe. The Shell of this isolated sphere is currently expanding at a speed faster than the speed of light. In this perspective, dark matter and energy are the same space mesh that have been compressed to varying degrees. Dark energy, which is constantly being released from the Shell into the cosmos, unlike the standard model of cosmology, is one of the factors in the expansion of the isolated cosmos by creating positive pressure in it. Also in this model, the recombination epoch will always be located spherically at a certain distance from the Shell until the ultimate stage of Rebound. In other words, not only is the origin of the CMB not related to the past of the cosmos, but it also exists now, and given the vastness of the sphere and the position of the Earth within this sphere, we detect it in the microwave wavelength with a delay of several billion years. Therefore, the observed distant galaxies that have been attributed to the early epochs of the cosmos in the Big Bang model are currently being created by the Shell according to the Spherical Cosmos Model, and we are surrounded by particles and objects that are constantly being produced.

A Candidate Supermassive Black Hole in a Gravitationally Lensed Galaxy at Z ≈ 10

While supermassive black holes (SMBHs) are widely observed in the nearby and distant Universe, their origin remains debated with two viable formation scenarios with light and heavy seeds. In the light seeding model, the seed of the first SMBHs form from the collapse of massive stars with masses of 10–100 M ⊙, while the heavy seeding model posits the formation of 104–5 M ⊙ seeds from direct collapse. The detection of SMBHs at redshifts z ≳ 10, edging closer to their formation epoch, provides critical observational discrimination between these scenarios. Here, we focus on the JWST-detected galaxy, GHZ 9, at z ≈ 10 that is lensed by the foreground cluster, A2744. Based on 2.1 Ms deep Chandra observations, we detect a candidate X-ray active galactic nucleus (AGN), which is spatially coincident with the high-redshift galaxy, GHZ 9. The SMBH candidate is inferred to have a bolometric luminosity of (1.0−0.4+0.5)×1046ergs−1 , which corresponds to a black hole (BH) mass of (8.0−3.2+3.7)×107M⊙ assuming Eddington-limited accretion. This extreme mass at such an early cosmic epoch suggests the heavy seed origin for this BH candidate. Based on the Chandra and JWST discoveries of extremely high-redshift quasars, we have constructed the first simple AGN luminosity function extending to z ≈ 10. Comparison of this luminosity function with theoretical models indicates an overabundant z ≈ 10 SMBH population, consistent with a higher-than-expected seed formation efficiency.

New Numerically Derived Scaling Relationships for Impact Basins on Mars

AbstractMost impact basins are believed to have formed during the early epochs of planetary evolution. The planet's gravity, internal structure, and thermal regime have the strongest control over their formation. Because of this, we can use the geophysical constraints on Mars' interior composition, structure, and geophysical evolution derived from the InSight mission to better understand the formation of impact basins on the planet. To achieve this, we performed numerical simulations of large impacts using the iSALE shock physics code. We investigated the effects of temperature and crustal thickness variations on impact basin size and morphology. Our scaling relationships indicate that: (a) basins formed in a warmer crust have larger final diameters in comparison to basins formed in a colder crust, a difference that is further accentuated as basin size gets bigger; and (b) the largest impact basins on Mars were created by impactors ranging from 35 to 680 km in diameter, up to ∼32% larger than estimates based on classical scaling. Our results expand the current understanding of the extent of early and large impact bombardment on Mars and provide a more comprehensive knowledge of impact basin formation on planetary surfaces.

Metallogenetic epoch and material source of Be-pegmatite differentiated from biotite granite in Mufushan complex

The Mufushan Complex (MFSC) is a significant rare metal mineralized in the central China district and is renowned for its marked economic value of rare metal deposits. While the main rare metal mineralization (RMM) stage in the MFSC relates to the magmatic event of two-mica monzogranite, the mineralization event related to biotite monzogranite remains unknown. To fill this gap, this study focuses on porphyritic biotite monzogranite and adjacent Be-rich pegmatite samples obtained from Changqing Pegmatite No. 1, which is situated in the southeastern part of the MFSC. We subjected these samples to zircon U–Pb dating and Hf isotope analysis using laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) and utilized an electron probe X-ray microanalyzer (EPMA) and LA–ICP–MS to examine the major and trace elements present in the muscovite samples. Our findings revealed precise chronological data for the geological history of Changqing, pinpointing the intrusion age of biotite monzogranite to 145.8 ± 1.1 Ma and the crystallization age of Be-rich pegmatite to 144.9 ± 1.1 Ma, firmly situating these events within the Late Jurassic to Early Cretaceous epoch. Regarding isotopic composition, zircon εHf (t) for granite ranged from −9.29 to −5.09, and their corresponding TDM2 ranged from 1788 to 1520 Ma. Similarly, zircon εHf (t) for pegmatite ranged from −7.89 to −5.47, and their corresponding TDM2 ranged from 1699 to 1544 Ma. These isotopic signatures strongly indicate a shared origin for the initial magma of granite and pegmatite. The partial melting of the thick Lengjiaxi Group tasedimentary strata serves as a material source for RMM. The transition from granite to pegmatite exhibits remarkable constancy in the primary components of muscovite. By examining its geochemical attributes, we observed synchronous decreases in FeO, MgO, SiO2, MnO, Be, Rb, and Cs, coupled with synchronous increases in Nb and Ta contents, along with Ta/Nb values. These findings strongly imply that the Changqing biotite monzogranite and Be-rich pegmatite originate from the continuous differentiation and evolution of a common magmatic source, establishing a clear genetic relationship between them. The MFSC has its origins in three distinct stages of magmatic activity and RMM spanning from 160 Ma to 120 Ma. Considering the distribution patterns of similar pegmatite veins, the metallogenic potential observed during the biotite granite stage may serve as an external indicator of marked mineralization within large batholiths.

Distillation embedded absorbable pruning for fast object re-identification

Combining knowledge distillation (KD) and network pruning (NP) shows promise in learning a light network to accelerate object re-identification. However, KD requires an untrained student network to establish more critical connections in early epochs, but NP demands a well-trained student network to avoid destroying critical connections. This presents a dilemma, potentially leading to a collapse of the student network and harming object Re-ID performance. For that, we propose a distillation embedded absorbable pruning (DEAP) method. We design a pruner-convolution-pruner (PCP) unit to resolve the dilemma by loading NP’s sparse regularization on extra untrained pruners. Additionally, we propose an asymmetric relation knowledge distillation method. It readily transfers feature representation knowledge and asymmetric pairwise similarity knowledge without using additional adaptation modules. Finally, we apply re-parameterization to absorb pruners of PCP units to simplify student networks. Experiments demonstrate the superiority of DEAP, such as on the VeRi-776 dataset, with ResNet-101 as a teacher, DEAP saves 73.24% of model parameters and 71.98% of floating-point operations without sacrificing accuracy.

The epoch of the Milky Way’s bar formation: dynamical modelling of Mira variables in the nuclear stellar disc

ABSTRACT A key event in the history of the Milky Way is the formation of the bar. This event affects the subsequent structural and dynamical evolution of the entire Galaxy. When the bar formed, gas was likely rapidly funnelled to the centre of the Galaxy settling in a star-forming nuclear disc. The Milky Way bar formation can then be dated by considering the age distribution of the oldest stars in the formed nuclear stellar disc. In this highly obscured and crowded region, reliable age tracers are limited, but bright, high-amplitude Mira variables make useful age indicators as they follow a period–age relation. We fit dynamical models to the proper motions of a sample of Mira variables in the Milky Way’s nuclear stellar disc region. Weak evidence for inside-out growth and both radial and vertical dynamical heating with time of the nuclear stellar disc is presented, suggesting that the nuclear stellar disc is dynamically well-mixed. Furthermore, for Mira variables around a ∼350-d period, there is a clear transition from nuclear stellar disc-dominated kinematics to background bar-bulge-dominated kinematics. Using a Mira variable period–age relation calibrated in the solar neighbourhood, this suggests the nuclear stellar disc formed in a significant burst in star formation $(8\pm 1)\, \mathrm{Gyr}$ ago, although the data are also weakly consistent with a more gradual formation of the nuclear stellar disc at even earlier epochs. This implies a relatively early formation time for the Milky Way bar ($\gtrsim 8\, \mathrm{Gyr}$), which has implications for the growth and state of the young Milky Way and its subsequent history.

Фактор законченности музыкальной формы: к вопросу об исторической эволюции

The study aims to substantiate that already in the early epochs (the Middle Ages, the Renaissance, the Baroque), there was a gradual birth of musical form functionality, one of the first signs of which was represented by composers’ awareness of the need to achieve the structural integrity and completeness of a work. The paper shows that the role of the main formative means was played by those compositional factors that were most actively developing in a particular epoch. The scientific novelty of the study lies in the specific identification of these compositional factors: the rhythmic one in the isorhythmic motets of the 14th century, the large-scale structural one in the textual and musical forms of the Renaissance, the functional harmonic one in Baroque works. As a result, it has been found that a change towards a decrease in the tenor’s measure at the last repetition of the melody of Gregorian chant turned out to be the factor of musical form completeness in Ph. de Vitry’s isorhythmic motets; in the motets, madrigals and polyphonic songs of the Renaissance, a large-scale enlargement of the final textual and musical segment of the form performed a similar function; as for the instrumental Baroque genres (preludes, toccatas, fantasias), such was the case with the increased harmonic stability of the last section (a tonic organ point, repetition of cadence turns).

The Geotectonic Peculiarities of the North Caspian Permian Salt-Bearing Basins (Kazakhstan)

This article examines the geotectonic and sedimentary features of the Upper Devonian–Carboniferous–Permian deposits of the North Caspian basin, represented by deposits of marine Paleozoic-isolated carbonate platforms formed during the subsidence of the basement on the passive continental margin. The top is covered by thick salt-bearing Kungurian deposits from the end of the Early Permian epoch. The formation of carbonate platforms is associated with a major tectonic restructuring of the basin at the turn of the Caledonian and Hercynian eras, when the Paleo-Tethys Ocean was formed and isolated carbonate islands began to grow in an open marine environment. The central part of the depression experienced a long and gradual subsidence that spanned the entire Paleozoic era and the beginning of the Mesozoic era. In the south and east, from the Devonian to the Permian periods, barriers were formed in the form of island carbonate massifs that separated the North Caspian basin from the Paleo-Tethys Ocean. During the formation of the salt-bearing basin, these barriers limited water exchange and ensured a one-way influx of sea water from the open ocean. As a result, at the end of the Permian period, thicker salts accumulated; however, during the collision of the continental massifs, an invasion of many kilometers of redbeds occurred. They initially stopped salt accumulation; however, gradually, in the north of the Caspian Sea during Roadian times, the salt accumulation continued. The post-Roadian time is associated with the influx of large quantities of redbed sediments, which caused gravitational instability in the underlying salt, and salt tectonics began with the formation of domal structures.