Search

Charge conservation and the Pauli exclusion principle result from fundamental symmetries in the standard model of particle physics, and are typically taken as axiomatic. High-precision tests for small violations of these symmetries could point to new physics. Here we consider three models for violation of these processes, which would produce detectable ionization in the high-purity germanium detectors of the Majorana Demonstrator experiment. Using a 37.5 kg yr exposure, we report a lower limit on the electron mean lifetime, improving the previous best limit for the e→νeνe¯νe decay channel by more than an order of magnitude. We also present searches for two types of violation of the Pauli exclusion principle, setting limits on the probability of an electron to be found in a symmetric quantum state.

With excellent energy resolution and ultralow-level radiogenic backgrounds, the high-purity germanium detectors in the Majorana Demonstrator enable searches for several classes of exotic dark matter (DM) models. In this work, we report new experimental limits on keV-scale sterile neutrino DM via the transition magnetic moment from conversion to active neutrinos ν_{s}→ν_{a}. We report new limits on fermionic dark matter absorption (χ+A→ν+A) and sub-GeV DM-nucleus 3→2 scattering (χ+χ+A→ϕ+A), and new exclusion limits for bosonic dark matter (axionlike particles and dark photons). These searches utilize the (1-100)-keV low-energy region of a 37.5-kg y exposure collected by the Demonstrator between May 2016 and November 2019 using a set of ^{76}Ge-enriched detectors whose surface exposure time was carefully controlled, resulting in extremely low levels of cosmogenic activation.

Supercontinuum sources based on intrapulse difference frequency generation (IDFG) from mode-locked lasers open new opportunities in mid-infrared gas spectroscopy. These sources provide high power and ultra-broadband spectral coverage in the molecular fingerprint region with very low relative intensity noise. Here, we demonstrate the performance of such a light source in combination with a multipass cell and a custom-built Fourier transform spectrometer (FTS) for multispecies trace gas detection. The light source provides a low-noise, ultra-broad spectrum from 2-11.5 µm with ∼3 W output power, outperforming existing mid-infrared supercontinuum sources in terms of noise, spectral coverage, and output power. This translates to an excellent match for spectroscopic applications, establishing (sub-)ppb sensitivity for molecular hydrocarbons (e.g., CH 4 , C 2 H 4 ), oxides (e.g., SO 2 , NO x ), and small organic molecules (e.g., acetone, ethyl acetate) over the spectral range of the supercontinuum source with a measurement time varying from seconds to minutes. We demonstrate a practical application by measuring the off-gas composition of a bioreactor containing an acidic ammonia-oxidizing culture with the simultaneous detection of multiple nitrogen oxides (NO, NO 2 , N 2 O, etc.). As the different species absorb various parts of the spectrum, these results highlight the functionality of this spectroscopic system for biological and environmental applications.

In humans, aneuploidy is incompatible with the birth of healthy children and mainly leads to the death of embryos in the early stages of development in the first trimester of pregnancy. Trisomy 16 is the most common aneuploidy among spontaneous abortions of the first trimester of pregnancy. However, the mechanisms leading to the death of embryos with trisomy 16 remain insufficiently investigated. One of these potential mechanisms is abnormal placental development, including aberrant remodeling of spiral arteries. Spiral artery remodeling involves the migration of trophoblast cells into the maternal spiral arteries, replacing their endothelium and remodeling to ensure a stable embryonic nutrition and oxygen supply. This is a complex process which depends on many factors from both the embryo and the mother. We analyzed the methylation level of seven genes (ADORA2B, NPR3, PRDM1, PSG2, PHTLH, SV2C, and TICAM2) involved in placental development in the chorionic villi of spontaneous abortions with trisomy 16 (n = 14), compared with spontaneous abortions with a normal karyotype (n = 31) and the control group of induced abortions (n = 10). To obtain sequencing libraries, targeted amplification of individual gene regions using designed oligonucleotide primers for bisulfite-converted DNA was used. The analysis was carried out using targeted bisulfite massive parallel sequencing. In the group of spontaneous abortions with trisomy 16, the level of methylation of the PRDM1 and PSG2 genes was significantly increased compared to induced abortions (p = 0.0004 and p = 0.0015, respectively). In the group of spontaneous abortions, there was no increase in the level of methylation of the PRDM1 and PSG2 genes, but the level of methylation of the ADORA2B gene was significantly increased compared to the induced abortions (p = 0.032). The results obtained indicate the potential mechanisms of the pathogenetic effect of trisomy 16 on the placental development with the participation of the studied genes., Competing Interests: The authors declare no conflict of interest., (Copyright © AUTHORS.)

Chlamydia abortus is the etiological agent of abortion and fetal loss in sheep, goats and bovine cattle in many countries. Even though commercially available vaccines can reduce the incidence in sheep, the development of new, safe, and effective vaccines remains high on the agenda. In this study, an evaluation was made of the efficacy of a vaccine candidate, an inactivated antigen based on the extract of outer membrane proteins of a C. abortus strain known as Chlamydia VNITIBP-21 , in combination with recombinant flagellin as an adjuvant. Pregnant sheep (n = 43) were divided into three groups: an experimental vaccinated group, a control infected group and a control non-infected group. The sheep were vaccinated twice, with an interval of 3 weeks, then infected with the homologous virulent strain of Chlamydia abortus on pregnancy day 75. The vaccine candidate reduced C. abortus shedding in vaginal swabs considerably, in comparison with the control group. In addition, ewes in the experimental group experienced no abortions, while those in the control group experienced instances of abortion, as well as births of weak and nonviable lambs. The findings show that the vaccine candidate proved itself to be promising in combatting the agent of ovine abortion and fetal loss.

We present a robust radiocarbon ( 14 C) chronology for burials at Sakhtysh, in European Russia, where nearly 180 inhumations of Lyalovo and Volosovo pottery-using hunter-gatherer-fishers represent the largest known populations of both groups. Past dating attempts were restricted by poor understanding of dietary 14 C reservoir effects (DREs). We developed a DRE correction approach that uses multiple linear regression of differences in 14 C, δ 13 C, and δ 15 N between bones and teeth of the same individuals to predict DREs of up to approximately 900 years. Our chronological model dates Lyalovo burials to the early fifth millennium BCE, and Volosovo burials to the mid-fourth to early third millennium. It reveals a change in the subsistence economy at approximately 3300 BCE, coinciding with a reorientation of trade networks, and dates the final burial to the early Fatyanovo period, the regional expression of the Yamnaya/Corded Ware expansion. Our approach is applicable when freshwater 14 C reservoir effects are poorly constrained and grave goods cannot be dated directly.

Western Eurasia witnessed several large-scale human migrations during the Holocene 1-5 . Here, to investigate the cross-continental effects of these migrations, we shotgun-sequenced 317 genomes-mainly from the Mesolithic and Neolithic periods-from across northern and western Eurasia. These were imputed alongside published data to obtain diploid genotypes from more than 1,600 ancient humans. Our analyses revealed a 'great divide' genomic boundary extending from the Black Sea to the Baltic. Mesolithic hunter-gatherers were highly genetically differentiated east and west of this zone, and the effect of the neolithization was equally disparate. Large-scale ancestry shifts occurred in the west as farming was introduced, including near-total replacement of hunter-gatherers in many areas, whereas no substantial ancestry shifts happened east of the zone during the same period. Similarly, relatedness decreased in the west from the Neolithic transition onwards, whereas, east of the Urals, relatedness remained high until around 4,000 BP, consistent with the persistence of localized groups of hunter-gatherers. The boundary dissolved when Yamnaya-related ancestry spread across western Eurasia around 5,000 BP, resulting in a second major turnover that reached most parts of Europe within a 1,000-year span. The genetic origin and fate of the Yamnaya have remained elusive, but we show that hunter-gatherers from the Middle Don region contributed ancestry to them. Yamnaya groups later admixed with individuals associated with the Globular Amphora culture before expanding into Europe. Similar turnovers occurred in western Siberia, where we report new genomic data from a 'Neolithic steppe' cline spanning the Siberian forest steppe to Lake Baikal. These prehistoric migrations had profound and lasting effects on the genetic diversity of Eurasian populations., (© 2024. The Author(s).)