Negative Mass Research Articles (Page 1)

The Jiaodong gold cluster region (JGCR) at the southeastern edge of the North China Craton (NCC), holding approximately 5000 t gold reserve, is the third largest gold cluster region in the world. The Bidimensional Empirical Mode Decomposition (BEMD) is applied in extracting gravity anomaly components showing deep geological architectures and geodynamics. The research results illustrate that (a) at a depth of about 27 km, there are three tectonic units, namely the mantle uplift (I) with gravity values ranging from 2 to 14 μm/s2, a mantle depression (II) with gravity values varying from 0 to −13 μm/s2, and a mantle flat (III) with gravity values ranging from −2 to 2 μm/s2. All giant gold deposits are distributed within the mantle depression. This implies that mantle uplift can trigger the concentration of hot, ore-forming fluids in mantle depressions, leading to the accumulation of large amounts of gold and the formation of giant deposits. (b) At about 17.1–12.5 km, there are three tectonic units: the Jiaolai–Jiaobei mantle uplift (I), showing a strong positive gravity anomaly with gravity values ranging from 1.5 to 10 μm/s2, the Sulu ultra-high pressure metamorphic block (II), displaying a negative gravity anomaly with gravity values ranging from −10 to −1.5 μm/s2, and the Jiaoxibei gold cluster region (III), exhibiting gravity background with gravity values varying from −1.5 to 1.5 μm/s2. (c) At about 8.9–5.3 km, there are a series of positive and negative gravity anomalies. Most granites with low density display negative gravity anomalies, among which there are some negative anomalies with positive anomalous edges which contain gold deposits. This illustrates an ore-forming pattern, a granite with negative gravity anomaly, around which there is alteration mineralization with positive gravity anomaly. Combined with other studies, it was concluded that the geological architectures at different depths as and the giant Jiaodong gold cluster region were formed by the asthenosphere upwelling triggered by NNW-ward subduction of the Izanagi Plate over a time period of approximately 200–100 Ma.

ABSTRACT The aim of this study was to investigate the effect of natural fiber additives in the negative (NAM) and positive (PAM) electroactive masses on the electrochemical properties of lead – acid cells. Natural, biodegradable fibers (flax and wool) were tested as substitutes for polyester. Conductivity of fiber suspensions in H₂SO₄ differed by only 3–4% from the neat electrolyte, with minor time-dependent drifts attributed to ion leaching. Pastes with flax and wool exhibited higher moisture contents (+20% for flax, +12–17% for wool vs. polyester), which promoted a more open, crystalline microstructure confirmed by SEM. Reactivity tests showed a mass gain upon acid soaking ~69% higher for PAM and ~108% higher for NAM compared to the standard. During formation, fiber-modified positive electrodes reached ~8 Ah capacity in the first cycle, whereas the standard required three cycles. Electrochemical impedance spectroscopy confirmed consistently lower charge transfer resistance (CRT), with wool plates showing a 4–8% reduction relative to the standard. These results demonstrate that natural fibers effectively modify the physicochemical and electrochemical properties of lead – acid battery electrodes, enabling faster formation, lower interfacial resistance, and improved performance while supporting the use of renewable and biodegradable materials.

Chromium(VI) is a carcinogen and mutagen, and its mechanism of action is proposed to involve binding of its reduction product, chromium(III), to DNA. Recently, this laboratory has shown that small oligonucleotide duplexes of DNA can be used to generate binary adducts of Cr(III). The structure of the Cr(III) binding site on the duplex DNA can be established using a combination of paramagnetic NMR, EPR, and FTIR spectroscopies. These studies have shown that aquated mononuclear Cr(III) or aquated hydroxo-bridged binuclear Cr(III) moieties bind to N-7 of guanine residues of the DNA depending on the DNA sequence. In the past determining which of these binary adducts formed required time-consuming variable temperature magnetic susceptibility and related experiments. Negative ion mass spectrometry (MS) can be utilized to efficiently identify whether mononuclear or binuclear binary Cr(III) adducts are formed.

The recent measurement of baryonic acoustic oscillations by the Dark Energy Spectroscopic Instrument reveals a mild tension with observations of the cosmic microwave background (CMB) within the standard Λ cold dark matter (ΛCDM) cosmological model. This discrepancy leads to a preference for a total neutrino mass that is lower than the minimum value inferred from neutrino oscillation experiments. Alternatively, this tension can be eased within ΛCDM by assuming a higher optical depth (τ≃0.09), but such a value conflicts with large-scale CMB polarization data. We point out that cosmic birefringence, as suggested by recent Planck reanalyses, resolves this discrepancy if the birefringence angle varies significantly during reionization. Specifically, we consider the fact that the measured cosmic birefringence angle β_{0}=0.34±0.09(1σ) deg has the phase ambiguity, i.e., the measured rotation angle is described by β=β_{0}+180n deg (n∈Z). We show that cosmic birefringence induced by axionlike particles with nonzero n suppresses the reionization bump, allowing a higher τ consistent with data. We provide a viable parameter space where the birefringence effect simultaneously accounts for the low-ℓ polarization spectra, the Planck EB correlations, and the elevated value of τ, suggesting a key role for cosmic birefringence in current cosmological tensions.

Spiral-like beams from diametric drive acceleration with positive and negative effective mass in a photonic lattice

This study uses data from the global satellite gravity model SDUST2021GRA and associated processing algorithms (upward continuation and tilt angle of the horizontal gradient) in delineating structural features and hydrocarbon distribution in the Cuu Long Basin (CLB). The gravity anomalies in the CLB are characterized by blocky development in the Northeast - Southwest (NE - SW) and North - South (N - S) direction. According to the changes in amplitudes, the regional gravity anomalies can be classified into four distinct zones. Analysis of gravity data in the CLB indicates that: three main sets of faults are developed in the region, namely, the NE - SW, N - S and NW - ES trending faults. NE - SW trending faults are distributed in a wide range, and they are main faults in the region. They are followed by N - S trending faults, while there are a small number of nearly NW - ES trending faults. Large - scale faults are mainly margin controlling faults for the boundary of the basin and uplifts . Through analysis of gravity anomaly characteristics, combined with location of oil/gas fields, the results show that oil/gas fields in the CLB are mainly located within zones of negative residual gravity anomalies. This approach provides a cost - effective tool for preliminary hydrocarbon exploration and structural evaluation in offshore basins.

Antioxidant activity of several organ and total aerial part extracts from Calendula aegyptiaca was investigated. Flavonoids and total phenol contents as well as ferric reducing power assay (FRAP), total antioxidant capacity (TAC), 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay revealed that methanolic extracts were richer in phenolics and flavonoids than Dichloromethane (DCM) and n-hexane extracts. The methanolic extract of the plant’s aerial part (MEAP) was found to have the highest phenolic content (385.06 ± 0.92 mg of Gallic acid equivalent/g of dried extract). The chemical profile of MEAP was explored through high-performance liquid chromatography combined with negative electrospray ionisation mass spectrometry (HPLC-HESI-MS). Twenty-nine compounds were identified, mostly composed of flavonoids (32.4%), phenolic acids (10.5%), and saponins (46.8%). By administering the MEAP to Wistar female rats in drinking water, its subacute toxicity was examined. Hematological, biochemical, histological and oxidative stress parameters were evaluated. Doses of 0.125, 0.250, 0.500, and 1.000 g of plant per kg of body weight did not cause damage in rats receiving this treatment. Nevertheless, a decrease in serum uric acid level was observed following extract administration. So, this extract may have antihyperuricemic activity which should be confirmed by using an animal model of hyperuricaemia.

Halogenated natural products (HNPs) are a diverse group of organohalogen compounds, predominantly found in the marine environment. Selected HNPs show structural similarity to persistent organic pollutants (POPs), but data on their occurrence is limited. An analytical method for the detection of 17 commonly reported HNPs, as well as selected POPs, using gas chromatography with electron-capture negative ionisation mass spectrometry (GC/ECNI-MS) was established and validated for salmon and blue mussel. The validation confirmed the applicability of the method with recovery rates and inter-day coefficients of variations of 52-101% and 3.7-16%, respectively. The subsequent application of the method to 17 samples of frequently consumed seafood products from the German retail market demonstrated its suitability for a wide variety of matrices. HNPs were detected in all analysed samples, with contents ranging from <0.05 to up to 7000ng/g lipid weight (lw). Highest median values were found for mixed-halogenated compound 1 (MHC-1), 2,4,6-tribromoanisole (2,4,6-TBA), and the heptachlorinated bipyrrole Q1 (19, 6.0, and 3.4ng/g lw, respectively). In 14 out of 17 analysed samples, the sum of HNPs was in the same concentration range or exceeded the sum of the investigated POPs, indicating the relevant exposure of consumers of seafood products in Germany to HNPs and emphasising the relevance of HNPs as organohalogen compounds in seafood samples.

The search for a neutron absorption material was aided by materials informatics tools that comprise the developed recommendation engines. A new member in the ternary RE10MCd3 series, Gd10RuCd3, was predicted and synthesized as an experimental validation. The recommendation engine is based on partial least-squares-discriminant analysis (PLS-DA) crystallographic site processing to classify the site preference of elements in compounds crystallizing in the Y10RuCd3-type structure and upon projecting other elements onto Principal Component map, the titled compound emerged as the top candidate. The distinguishing feature of the developed recommendation engine is in the three explainable methods utilized in the predictive framework: unrestricted, conservative, and cluster methods. Predictions are visualized with convenient property projection tools. The prediction was validated by high-temperature synthesis. The structure was confirmed with single-crystal and powder X-ray diffraction. The cold-water-quenched samples quenched at 800 °C have a smaller unit cell volume than the samples quenched at 600 °C annealing temperature. Transport property measurements show an unusually low thermal conductivity (5-7 W·m-1 K-1) and a trend change indicates a possible structure transition between 600 and 800 °C. The unusual low thermal conductivity was predicted with a machine-learning model that focuses on thermoelectric property prediction. DFT analysis reveals the presence of a 0D electride phenomenon. The neutron cross section and absorption based on the constituent elements put our material within the top 0.4% of neutron absorbers. The negative thermal expansion and high mass absorption suggest Gd10RuCd3 as an attractive neutron absorption material.

Mechanical analogy between the second-order Schrödinger equation without potential for the case of a particle in an ideal infinite well with the fourth-order Schrödinger equation in connection with the potential manifestation of negative mass in Bose–Einstein condensates and exciton–polaritons in cavity

The appearance of a negative mass term in the classical, non-relativistic Klein–Gordon equation deduced from mechanical interactions describes a repulsive interaction. In the case of a traveling wave, this results in an increase in amplitude and a decrease in the wave propagation velocity. Since this leads to dissipation, it is a symmetry-breaking phenomenon. After the repulsive interaction is eliminated, the system evolves towards the original state. Given that the interactions within the system are conservative, it would be assumed that even the original state is restored. The analysis to be presented shows that a wave with a lower angular frequency than the original one is transformed back to a slightly larger amplitude. This description is a suitable model of the axion effect, during which an electromagnetic wave interacts with a repulsive field and becomes of a continuously lower frequency.

Abstract At mid‐ocean ridges (MORs), accounting for plate cooling‐related long‐wavelength gravity anomalies is crucial for accurately estimating variations in crustal thickness and distributions of density anomalies within crust and mantle. Either the classic 1‐D plate cooling model (PCM) or numerical models incorporating complex heat advection‐conduction and melting processes are commonly employed for this purpose. However, the differences in gravity anomalies predicted by these thermal models have rarely been investigated. In this study, we quantitatively assess the sensitivity of gravity anomalies to various mantle thermal models, considering the influence of mantle rheology‐related heat advection and latent heat of melting (LHM). Our results indicate that the PCM systematically overestimates the mantle temperature, predicting more pronounced negative gravity anomalies near the ridge axis compared to numerical models, with peak deviations exceeding 10 mGal and increasing as spreading rates decrease. The comparatively more positive gravity anomalies in numerical models are attributed to efficiency of rheology‐related heat advection and LHM. Heat advection generally decreases as spreading rates decrease, resulting in more positive gravity anomalies which modulated by mantle rheologies. In contrast, LHM contributes to less positive gravity anomalies at slower spreading rates due to lower degrees of melting. Specifically, effect of LHM that commonly ignored in gravity modeling plays a more significant role than rheology‐related heat advection in influencing axial gravity anomalies at intermediate‐ to fast‐spreading rates. Our systematic work distinguishes the differences in gravity anomalies predicted by various mantle thermal models, providing insights for interpretation of local gravity anomalies at global MORs.

Abstract Glacier mass balance is a key indicator of climate change, with most glaciers worldwide exhibiting negative trends due to rising temperatures. However, Adishi Glacier in the Central Caucasus presents an anomaly published by earlier studies. This research uses Ice, Clouds and Land Elevation Satellite‐2 altimetry data (2018–2024) and the Shuttle Radar Topography Mission Digital Elevation Model to assess recent elevation changes and mass balance variations. ERA5 reanalysis data were used to examine potential climatic drivers. Results show persistent thinning in lower glacier regions, while the accumulation area demonstrates sustained elevation gains. The equilibrium line altitude shows a slight upward trend (+3.07 m/year), consistent with global patterns. Notably, Adishi Glacier exhibited a positive mass balance of 0.05 ± 0.17 m w.e. a−1 in 2021 and 0.03 ± 0.06 m w.e. a−1 in 2024, but the mean for 2018–2024 remains negative at −0.31 ± 0.09 m w.e. a−1. This suggests that, despite short‐term gains, the anomaly is not sustained. Compared to the neighbouring glaciers—Bezengi, Khalde, Tsaneri North and South—which show continuous negative mass balances, Adishi's stability stands out. Regional warming (+0.19°C/year) based on ERA5 reanalysis contributes to ablation zone losses, but glacier hypsometry, with an extensive accumulation area above 4,000 m a.s.l., and orographic effect of snowfall on windward slopes support temporary gains. These favourable conditions, however, are insufficient to maintain a long‐term positive mass balance under ongoing climate change.

The present research investigated the role of a pervasive and often negative form of indirect contact, exposure to mass media news on interethnic contact. Specifically, we examined the associations between mass media exposure and both African immigrants' attitudes toward native Italians and their collective action intentions to achieve higher intergroup equality in the host country. We conducted two survey studies, one cross-sectional (Study 1, N = 285) and the second longitudinal (Study 2, N = 423) with African immigrants living in Italy. Exposure to negative mass media news was linked to less positive attitudes toward native Italians and more collective action of African immigrants. The negative link between negative mass media news exposure and intergroup attitudes was stronger for those African migrants who reported relatively low positive and negative direct intergroup contact. These findings were consistent across both studies. The positive link between negative mass media news exposure and collective action was stronger among African immigrants with relatively low negative direct intergroup contact. The evidence illustrates the independent and combined ways in which the valence of direct and indirect contact can affect immigrants' attitudes toward natives, and their motivation to build a more inclusive and equal society. Overall, results highlighted the greater strength of negative rather than positive indirect contact of immigrants, especially when they reported less positive direct contact experience with native Italians. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

The first comprehensive mass balance estimation for the world’s largest tropical icefield is presented. Geodetical mass balance was calculated using photogrammetry from aerial and satellite images spanning from 1955 to 2024. The results meet expected quality standards using some new satellite sources, such as the Peruvian PeruSAT-1, although the quality of airborne imagery is consistently lower than that of satellite sources. The Nevado Coropuna icefield remained almost stable between 1955 and 1986 with −0.04 m dh yr−1. Since then, it has undergone a sustained and accelerated negative mass balance, reaching a maximum annual dh yr−1 of −0.73 ± 0.19 in the 2020–2023 timeframe. The glacier loss is not equal across the entire ice mass, but more acute in the northern and northeastern outlet tongues. Debris-covered ice and rock glaciers show a much weaker negative mass balance signal. The impact of ENSO events is not evident in the overall ice evolution, although their long-term relevance is acknowledged. Overall, the negative response of Nevado Coropuna to global warming (−0.36 ± 0.12 m.w.e. yr−1 for the 2013 to 2024 period) is less pronounced than that of other Peruvian glaciers, but more severe than that reported for the nearby Dry Andes of Chile and Argentina.

This study examines the Secondary Transfer Effect (STE) in a non-Western context by investigating how Japanese university students' contact with immigrants and LGBTQ individuals relates to their willingness to interact with Asian international students. Using data from 299 Japanese undergraduates and path analyses, we assessed four contact channels: direct interactions, traditional mass media, recreational media, and social media. Findings show that direct contact is strongly associated with perceived outgroup morality, making it the most reliable channel. Recreational media contact also correlates with higher perceived morality, suggesting it as another promising avenue. In contrast, traditional mass media and social media contacts show weaker or inconsistent links with outgroup morality, indicating that these channels may be less effective in fostering positive perceptions. The STE also differs as a function of the primary outgroup, the transfer medium and the psychological mechanism. For LGBTQ individuals, STE appears across all channels, while for immigrants it is most evident in direct contact and recreational media. Notably, negative traditional mass media contact with immigrants directly predicted willingness to interact-bypassing morality mediation-and negative news portrayals of LGBTQ individuals were paradoxically linked to higher perceived morality, highlighting how both the specific outgroup and the medium shape STE outcomes. Although immigrants and international students are generally viewed as separate social categories in Japan, we acknowledge some residual conceptual overlap and note this as a limitation. Overall, the study extends STE research beyond Western contexts and offers guidance for inclusivity interventions.

Acoustic focusing technology has demonstrated significant application prospects across multidisciplinary fields. Based on the principle of fractal self-similarity, this study proposes a novel fractal acoustic metamaterial. Calculations of equivalent acoustic parameters reveal that this structure exhibits near-zero density effects at frequencies of 2271 Hz and 3872 Hz. Further analysis elucidates the bandgap characteristics of the fractal unit, demonstrating that its formation mechanism stems from negative equivalent mass density induced by even-order resonance, thereby blocking sound wave propagation and generating bandgaps. Leveraging this principle, two types of near-zero-density acoustic focusing lenses were designed, achieving point focusing and line focusing functionalities, respectively. These lenses exhibit an acoustic diode effect, enabling asymmetric sound wave transmission. By reconfiguring the fractal structural units, the lens radius and aperture angle can be modified to achieve focal point positioning control. Subsequently, an analysis of the system robustness indicates that the designed acoustic focusing lenses possess commendable system robustness. Furthermore, a multi-directional focusing acoustic lens was designed, capable of focusing sound waves in different directions, thereby providing a design basis for omnidirectional acoustic focusing lenses. Finally, experimental measurements of the sound pressure field for Lens A were conducted. The measured results show close agreement with simulation analyses, confirming the structural effectiveness and computational accuracy.

The diametric drive self-acceleration of beams with positive and negative mass in nonlocal nonlinear media

A semi-analytic model formalism is systematically developed to analyze the effects of kappa-distributed lighter constituents and the resulting kappa-modified polarization force on the Jeans instability in EiBI-gravitating dust molecular clouds (DMCs). The lighter constituents (electrons and ions) are considered to follow non-thermal kappa-velocity distribution. The constitutive massive dust grains are treated as EiBI-gravitating fluids. A generalized linear quadratic dispersion relation is derived using spherical normal mode analysis without any quasi-classic approximation. The resulting dispersion relation is analyzed in both the hydrodynamic and kinetic regimes along with their corresponding modified instability criteria. The characteristics of oscillatory and propagatory modes are illustratively analyzed. It is seen that the EiBI gravity introduces a new velocity term, the EiBI-induced velocity, in the dispersion relation. In contrast, the non-thermal kappa-distributed constituents significantly enhance the polarization force against their respective Maxwellian counterparts. The kappa-modified polarization force and the negative EiBI gravity parameter have destabilizing influences, unlike that with the positive EiBI parameter. An enhanced polarization interaction parameter and positive EiBI parameter reduce the real normalized frequency. Consequently, the phase velocity exhibits strong dispersion, increasing with the wavenumber until reaching saturation, after which it transitions into a weakly dispersive regime. These findings provide new theoretical insights on the gravitational collapse mechanisms in the ultracompact Hii regions of dense DMCs towards bounded structure formation.

Individual differences in response to a chronic high-fat diet in striped hamsters (Cricetulus barabensis).