Matter Content Research Articles

Absorption of fermionic dark matter via the scalar portal

The absorption of fermionic dark matter has recently been studied as a signature for the direct detection of dark matter. We construct the first UV completion of the scalar effective operator associated with this signature. We calculate the constraints on the model and demonstrate there is viable parameter space which can be probed by a next-generation experiment such as XLZD. We also consider the cosmological history of our model and show that the correct relic abundance can be obtained via freeze-out in the dark sector. However, within this minimal model, we find that the absorption signal is highly suppressed in the parameter space that yields the correct relic abundance. Published by the American Physical Society 2024

Effect of surface functional groups of polystyrene micro/nano plastics on the release of NOM from flocs during the aging process

Currently, the hidden risk of microplastics in the coagulation process has attracted much attention. However, previous studies aimed at improving the removal efficiency of microplastics and ignored the importance of interactions between microplastics and natural organic matter (NOM). This study investigated how polystyrene micro/nano particles impact the release of NOM during the aging of flocs formed by aluminum-based coagulants Al13 and AlCl3. The results elucidated that nano-particles with small particle sizes and agglomerative states are more likely to interact with coagulants. After 7 years of floc aging, the DOC content of the nano system decreased by more than 40%, while the micron system did not change significantly. During coagulation, the benzene rings in polystyrene particles form complexes with electrophilic aluminum ions through π-bonding, creating new Al-O bonds. NOM tends to adsorb at micro/nano plastic interfaces due to hydrophobic interactions and conformational entropy. In the aging process, the structure of PS-Al13 or PS-AlCl3 flocs and the functional groups on the surface of micro/nano plastics control the absorption and release of organic matter through hydrophobic, van der Waals forces, hydration, and polymer bridging. In the system with the addition of nano plastics, several DBPs such as TCAA, DCAA, TBM, DBCM and nitrosamines were reduced by more than 50%. The reaction order of different morphological structures and surface functional groups of microplastics to Al13 and AlCl3 systems is aromatic C-H > C-OH > C-O > NH2 > aromatic CC > aliphatic C-H and C-O>H-CO> NH2 >C-OH> aliphatic C-H. The results provided a new sight to explore the effect of micro/nano plastics on the release of NOM during flocs aging.

Characterization and health risks of short- and medium-chain chlorinated paraffins in the gas and size-fractionated particulate phases in ambient air

Short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) have garnered significant attention because they have persistence and potential toxicity, and can undergo long-distance transport. Chlorinated paraffins (CPs) inhaled in the size-fractionated particulate phase and gas phase can carry different risks to human health due to their ability to accumulate in different regions of the respiratory tract and exhibit varying deposition efficiencies. In our study, large-volume ambient air samples in both the size-fractionated particulate phase (Dp < 1.0 μm, 1.0–2.5 μm, 2.5–10 μm, and Dp ≥ 10 μm) and gas phase were collected simultaneously in Beijing using an active sampler. The overall levels of SCCPs and MCCPs were relatively high, the ranges being 57–881 and 30–385 ng/m3, respectively. SCCPs tended to be partitioned in the gas phase (on average 75% of the ΣSCCP concentration), while MCCPs tended to be partitioned in the particulate phase (on average 62% of the ΣMCCP concentration). Significant correlations were discovered between the logarithm-transformed gas–particle partition coefficients (KP) and predicted subcooled vapor pressures (PL0) (p < 0.01 for SCCPs and MCCPs) and between the logarithm-transformed KP values and octanol–air partition coefficients (KOA) (p < 0.01 for SCCPs and MCCPs). Thus, the slopes indicated that organic matter absorption was the dominant process involved in gas–particle partitioning. We used the ICRP model to calculate deposition concentrations for particulate-associated CPs in head airways region (15.6–71.4 ng/m³), tracheobronchial region (0.8–4.8 ng/m³), and alveolar region (5.1–21.9 ng/m³), then combined these concentrations with the CP concentrations in the gas phase to calculate estimated daily intakes (EDIs) for inhalation. The EDIs for SCCPs and MCCPs through inhalation of ambient air for the all-ages group were 67.5–184.2 ng/kg/day and 19.7–53.7 ng/kg/day, respectively. The results indicated that SCCPs and MCCPs in ambient air do not currently pose strong risks to human health in the study area.

The Evolution of Geospheres on an Expanding Earth

The evolution of the geosphere is considered in the light of the expanding Earth hypothesis, an alternative concept of plate tectonics, the fifth axiom of which is the statement about the immutability of the mass and size of the Earth, as well as the mass of water on its surface. A new look at the evolution of the Earth and its geospheres (lithosphere, hydrosphere, cryosphere and biosphere.) is proposed. The physical mechanisms of the not yet understood processes of increasing its size with a simultaneous increase in mass are discussed. For the first time, a physical scenario of the expansion process is proposed. It consists in the constant absorption of dark matter by the Earth in the form of quark nuggets (strangelets), followed by their decay and transformation into ordinary matter. The expansion of the Earth makes it possible to explain not only the large size and mass of land animals at the end of the Paleozoic and Mesozoic, but also to establish the most probable causes of the movement of continents and Great Extinctions.

Absorption of Axion Dark Matter in a Magnetized Medium.

Detection of axion dark matter heavier than an meV is hindered by its small wavelength, which limits the useful volume of traditional experiments. This problem can be avoided by directly detecting in-medium excitations, whose ∼meV-eV energies are decoupled from the detector size. We show that for any target inside a magnetic field, the absorption rate of electromagnetically coupled axions into in-medium excitations is determined by the dielectric function. As a result, the plethora of candidate targets previously identified for sub-GeV dark matter searches can be repurposed as broadband axion detectors. We find that a kg yr exposure with noise levels comparable to recent measurements is sufficient to probe parameter space currently unexplored by laboratory tests. Noise reduction by only a few orders of magnitude can enable sensitivity to the QCD axion in the ∼10 meV-10 eV mass range.

Spherical warp-based bubble with non–trivial lapse function and its consequences on matter content

In the present work, we study the consequences of including the lapse function as an additional degree of freedom for a general spherical warp-based geometry. By allowing a non-uniform lapse function to evolve, we find that it is possible to accommodate a fluid that includes heat flow. This broadens the range of fluid types that have been studied in these systems and is consistent with the spherical warp metric. Having added the lapse function, we solved the system of equations using an anisotropic fluid with heat flow. In this way, we can examine the different characteristics of the variables of the system. Next, we study the energy conditions and establish how these are modified by including heat flux for an appropriate generic observer in a locally flat spacetime. Finally, we explore all energy conditions using the numerical solutions and verify the regions where they are satisfied.

[formula omitted] gravity theory in Einstein space background and causality violation

In this paper, we exploration a Petrov type-N vacuum solution to Einstein’s field equations, while incorporating a negative cosmological constant (Λ<0) within the framework of modified gravity theories. This solution intriguingly accommodates closed time-like curves at a particular moment in time, effectively violates the causality condition, thus acts as a time-machine model. A key observation is that the determinant of the Ricci tensor Rμν for this particular Einstein space metric differs from zero. This noteworthy finding suggests to the existence of an anti-curvature tensor defined Aμν=Rμν−1 and hence, an anti-curvature scalar A=gμνAμν, which is introduced with the Lagrangian of the system, thereby giving rise to as Ricci-inverse gravity theory. We consider class-I models of Ricci-inverse gravity, where the function f=f(R,A)=(R+κA) with κ is the coupling constant. We demonstrate that this Einstein space metric serves as a vacuum solution with a negative modified cosmological constant within the framework of Ricci-inverse gravity. Consequently, the violation of causality persists within this new gravity theory as well. Moreover, we solve the modified field equations by considering matter content other than vacuum and demonstrate that the energy-density and isotropic pressure satisfies the equation ρ=−p=3κΛ.

Anomalies of generalized symmetries from solitonic defects

We propose the general idea that ’t Hooft anomalies of generalized global symmetries can be understood in terms of the properties of solitonic defects, which generically are non-topological defects. The defining property of such defects is that they act as sources for background fields of generalized symmetries. ’t Hooft anomalies arise when solitonic defects are charged under these generalized symmetries. We illustrate this idea for several kinds of anomalies in various spacetime dimensions. A systematic exploration is performed in 3d for 0-form, 1-form, and 2-group symmetries, whose ’t Hooft anomalies are related to two special types of solitonic defects, namely vortex line defects and monopole operators. This analysis is supplemented with detailed computations of such anomalies in a large class of 3d gauge theories. Central to this computation is the determination of the gauge and 0-form charges of a variety of monopole operators: these involve standard gauge monopole operators, but also fractional gauge monopole operators, as well as monopole operators for 0-form symmetries. The charges of these monopole operators mainly receive contributions from Chern-Simons terms and fermions in the matter content. Along the way, we interpret the vanishing of the global gauge and ABJ anomalies, which are anomalies not captured by local anomaly polynomials, as the requirement that gauge monopole operators and mixed monopole operators for 0-form and gauge symmetries have non-fractional integer charges.

BTZ black hole in [formula omitted] gravity and thermodynamic properties

In this study, we aim to investigate the rotating Banados-Teitelboim-Zanelli (BTZ) black hole (BH) solution within the framework of modified gravity theories. Notably, our investigation reveals that the BTZ BH space–time serves as a solution within the framework of Ricci-inverse (RI) gravity, particularly within Class-I models defined by f(R,A)=(R+αA). Here, R=gμνRμν and A=gμνAμν denote the Ricci and anti-curvature scalars, respectively, while α represents the coupling parameter. We show that this new modified theory induces modifications to the cosmological constant, demonstrating the influence of the coupling parameter α when analyzed in a vacuum as matter content. Additionally, we study the thermodynamic properties of this BTZ BH solution obtained within the RI-gravity framework and analyze the associated physical quantities. It is evident that the thermodynamic parameters, including BH horizons, Hawking temperature, entropy, free energy, internal energy, and specific heat capacity, undergo alterations due to the coupling constant α. Specifically, when α=0, our findings align with the outcomes documented in existing literature obtained in the general relativity (GR) context using the BTZ BH solution.

Doped semiconductor devices for sub-MeV dark matter detection

Dopant atoms in semiconductors can be ionized with ∼10 meV energy depositions, allowing for the design of low-threshold detectors. We propose using doped semiconductor targets to search for sub-MeV dark matter scattering or sub-eV dark matter absorption on electrons. Currently unconstrained cross sections could be tested with a 1 g-day exposure in a doped detector with backgrounds at the level of existing pure semiconductor detectors, but improvements would be needed to probe the freeze-in target. We discuss the corresponding technological requirements and lay out a possible detector design. Published by the American Physical Society 2024

A new software toolkit for optical apportionment of carbonaceous aerosol

Abstract. Instruments measuring aerosol light absorption, such as the Aethalometer and the Multi-Wavelength Absorbance Analyzer (MWAA), have been extensively used to characterize optical absorption of atmospheric particulate matter. Data retrieved with such instruments can be analysed with mathematical models to apportion different aerosol sources (Aethalometer model) and components (MWAA model). In this work we present an upgrade to the MWAA optical apportionment model. In addition to the apportionment of the absorption coefficient babs in its components (black carbon and brown carbon) and sources (fossil fuels and wood burning), the extended model allows for the retrieval of the absorption Ångström exponent of each component and source, thereby avoiding initial assumptions regarding these parameters. We also present a new open-source software toolkit, the MWAA model toolkit (MWAA_MT), written in both Python and R, that performs the entire apportionment procedure.

Exploring the applicability of traversable wormhole formation in [formula omitted] gravity

In this work, we construct three different models of static wormhole (WH) geometries within the realm of f(R,Lm) gravity theory. We start by deriving the corresponding field equations for the Morris–Thorne WH geometry in the context of anisotropic matter distribution under the generic form of f(R,Lm) gravity. By adequately specifying the key features of three different shape function models generated with different assumptions about their matter content, and assuming that WHs exert no tidal force by setting the gravitational redshift function to be a constant or φ′(r)=0, we disclose a variety of exact WH solutions in the theory. Our exact solutions for f(R,Lm) show that for all three classes of WHs found, the energy density is consistently positive in all spacetime, while the radial pressure is negative. This signifies that exotic matter is mandatory for the existence of WHs in f(R,Lm) gravity. We have also applied the energy conditions (ECs) for the WHs’ physical content and found that exact WH models are filled with exotic matter that violates the necessary ECs throughout spacetime and makes them compatible and traversable.

Exotic Dark Matter Search with the Majorana Demonstrator

With excellent energy resolution and ultralow-level radiogenic backgrounds, the high-purity germanium detectors in the 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 νs→νa. 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 between May 2016 and November 2019 using a set of Ge76-enriched detectors whose surface exposure time was carefully controlled, resulting in extremely low levels of cosmogenic activation. Published by the American Physical Society 2024

Effective field theory for dark matter absorption on single phonons

Single phonon excitations, with energies in the 1–100 meV range, are a powerful probe of light dark matter (DM). Utilizing effective field theory, we derive a framework to compute DM absorption rates into single phonons starting from general DM-electron, proton, and neutron interactions. We apply the framework to a variety of DM models: Yukawa coupled scalars, axionlike particles with derivative interactions, and vector DM coupling via gauge interactions or Standard Model electric and magnetic dipole moments. We find that GaAs or Al2O3 targets can set powerful constraints on a U(1)B−L model, and targets with electronic spin ordering are similarly sensitive to DM coupling to the electron magnetic dipole moment. Lastly, we make the code, (an extension of the existing code which computes general DM–single phonon scattering rates), publicly available. Published by the American Physical Society 2024

The determination of the mass absorption coefficient of particulate matter using measurements of spectral reflectance and impurity mass concentration

The determination of the mass absorption coefficient of particulate matter using measurements of spectral reflectance and impurity mass concentration

Антропогенді ластаған биогеоценоздарды диагностикалауда топырақ мезофаунасының түр құрамын пайдалану

Soil invertebrates are an important driving force behind many basic soil processes, such as the formation of soil aggregates, water retention, and absorption of organic matter. Earthworms, being permanent inhabitants of the soil, play the role of an indicator transmitting information about the state of this environment. In this work, anthropogenic pollution of urban and suburban biogeocenoses was revealed by studying the species composition and abundance of lumbricides. Soil samples were taken from 8 sites in Almaty and the region, physico-chemical parameters were studied. In background and slightly polluted biogeocenoses, the number of earthworms averages 64.6%, and in polluted regions 55.2%. When determining the content of toxic elements in urban and background (natural) biocenoses, four main elements were identified that affect the species and quantitative composition of the mesofauna: lead, cadmium, arsenic and mercury. The maximum content of cadmium and arsenic is observed in soils near oil depots: the cadmium content was 0.25±0.0024 mg/kg, and the arsenic content was 2.84±0.05 mg/kg. And in the soil near the thermal power plant of the Algabas microdistrict of the Alatau district, the maximum content of lead and mercury was recorded, which reached 16±0.70 mg/kg and 0.048±0.012 mg/kg, respectively.

Polynomial Deceleration Parameter Explaining Bianchi Type I Model

The focus of the current research investigates the dynamical behavior of the universe within the framework of a new Bianchi type-I anisotropic, homogeneous astrophysical models with a modified theory of f(R, T) gravity. The significant effect of the model is to find solutions to the field equations using Polynomial Deceleration Parameter (PDP) which is a powerful tool to analyze the cosmic expansion history. Through a combination of theoretical analysis and graphical representation, we explore the consequences of f(R, T) gravity on the universe’s evolution for r = 1 to 5 polynomial value of DP. Our study unveils intriguing features in the context of this modified gravity theory, shedding light on its impact on cosmic expansion, acceleration, and potential deviations from standard cosmological models. The graphical representations provide intuitive insights, enhancing our comprehension of the complex interplay between geometry and matter content in the universe. This research contributes to a deeper understanding of the universe’s behavior in alternative gravitational theories. GANIT J. Bangladesh Math. Soc. 43.1 (2023) 08- 25

Meningkatkan Minat dan Hasil Belajar KD Mengkonsumsi Makanan dan Minuman yang Halal dan Menjauhi yang Haram dengan Metode Gallery Walk pada Siswa Kelas VIIIA Semester 2 SMP Negeri 4 Purworejo

This research is based on the importance of increasing KD interest and learning outcomes in consuming halal food and drinks and avoiding haram ones using the Walk Gallery method in Class VIIIA Semester 2 of SMP Negeri 4 Purworejo. The aim of this research is to increase PAIBP's interest and learning outcomes in the material Consuming Halal Food and Drinks and Avoiding Haram for class VIIIA Semester 2 students at SMP Negeri 4 Purworejo. The method used in this Classroom Action Research is the Walk Gallery learning method. The subject of this Class Action Research is class VIIIA of SMP Negeri 4 Purworejo for the 2019/2020 academic year. The number of students is 32 consisting of 12 boys and 20 girls, namely from January to March 2020 in the even semester. Each cycle consists of planning, implementation, observation and reflection. The research procedure consists of pre-research, cycle one planning, implementation of cycle one actions, observation cycle one, reflection cycle one. This research produces the following conclusions. (1) The Gallery Walk method can increase interest in learning, namely activating all students in the learning process by visiting observers to other galleries and representatives of gallery attendants to exchange information on the material being discussed. This can be seen from the increase in interest in listening to explanations in cycle I from 84%, cycle II to 100%, interest in doing assignments from 78% to 93%, interest in seeking information from 68% to 78%, and interest in participating in groups from 81% to 93%. (2) Using the Gallery Walk method can improve student learning outcomes. Students' learning completeness and absorption of subject matter always increases, starting in cycle I, 75% of students have completed learning with an absorption capacity of 79.22%, then in cycle II there has been an increase, namely 100% of students have completed learning with an absorption capacity of 87%. .03%.

Balance™ methodology – converting carbon finance to biodiversity creation

ABSTRACT This paper addresses two interlinked problems in sustainable development and suggests a methodology to resolve them. The first is the reduction of atmospheric greenhouse gas emissions, especially carbon dioxide. The second is the maintenance of biodiversity. Current carbon financing and environmental stewardship mechanisms underwhelm, often diluting intended positive effects. Most existing carbon credits do not have protection after 40 years, placing projects substantially beneath the C02 radiative forcing cycle. This paper presents the ‘Balance’ approach to sustainable development, including contractual principles ensuring C02 reduction, biodiversity enhancement and financial accountability. We describe two novel measures: a carbon calculator for commercial entities, and a new metric, the Balance Unit, combining biodiversity creation with carbon credits. A case study, spanning over 20 years at the Forest of Marston Vale, is then presented. It finds an increase in tree cover, CO2 sequestration, reduction in agricultural GHG emissions, sulphur dioxide and particulate matter absorption, and annual local economic benefits totalling £UK12.83 million. Expository detail regarding the ‘Planting Principles’ practised at Marston Vale is also provided. We argue that the Balance methodology, especially the Balance Unit, enables greater measurement reliability and long-term efficacy for maintaining biodiversity and reducing GHG emissions than current carbon financing approaches.

Finiteness of quantum gravity with matter on a PL spacetime

We study the convergence of the path integral (PI) for general relativity with matter on a picewise linear (PL) spacetime that corresponds to a triangulation of a smooth manifold by using a PI measure that renders the pure gravity PI finite. This measure depends on a parameter p, and in the case when the matter content is just scalar fields, we show that the PI is absolutely convergent for 0,5 and not more than two scalar fields. In the case of Yang–Mills (YM) fields, we show that the PI is absolutely convergent for the U(1) group and 0,5. In the case of Dirac fermions, we show that the PI is absolutely convergent for any number of fermions and a sufficiently large p. When the matter content is given by scalars, YM fields and fermions, as in the case of the standard model (SM), we show that the PI is absolutely convergent for 52,5. Hence one can construct a finite quantum gravity theory on a PL spacetime such that the classical limit is general relativity coupled to the SM.