Matter Components Research Articles

Oxidative Depolymerisation of Kraft Lignin: From Fabrication of Multi‐Metal‐Modified Electrodes For Vanillin Electrogeneration via Pulse Electrolysis To High‐Throughput Screening of Multi‐Metal Composites

AbstractThe production of green hydrogen may be greatly aided by the use of an alternative anode reaction replacing oxygen evolution to increase energy efficiency and concomitantly generate value‐added products. Lignin, a major component of plant matter, is accumulated in large amounts in the pulp and paper industry as waste. It has excellent potential as a source of aromatic compounds and can be transformed into the much more valuable aroma chemical vanillin by electrochemical depolymerisation. We used a flow‐through model electrolyser to evaluate electrocatalyst‐modified Ni foam electrodes prepared by a scalable spray‐polymer preparation method for oxidative lignin depolymerisation. We demonstrate how pulsing, i. e. continuously cycling between a lower and a higher applied current, increases the amount of formed vanillin while improving the energy efficiency. Further, we present a scanning droplet cell‐assisted high‐throughput screening approach to discover suitable catalyst materials for lignin electrooxidation considering that a suitable electrocatalyst should exhibit high activity for lignin depolymerization and simultaneously a low activity for vanillin oxidation and oxygen evolution. Combining electrosynthesis and electrocatalysis can aid in developing new customised materials for electrochemical processes of potential industrial interest.

Differential response of Hg-methylating and MeHg-demethylating microbiomes to dissolved organic matter components in eutrophic lake water

Methylmercury (MeHg) production in aquatic ecosystems is a global concern because of its neurotoxic effect. Dissolved organic matter (DOM) plays a crucial role in biogeochemical cycling of Hg. However, owing to its complex composition, the effects of DOM on net MeHg production have not been fully understood. Here, the Hg isotope tracer technique combined with different DOM treatments was employed to explore the influences of DOM with divergent compositions on Hg methylation/demethylation and its microbial mechanisms in eutrophic lake waters. Our results showed that algae-derived DOM treatments enhanced MeHg concentrations by 1.42−1.53 times compared with terrestrial-derived DOM. Algae-derived DOM had largely increased the methylation rate constants by approximately 1−2 orders of magnitude compared to terrestrial-derived DOM, but its effects on demethylation rate constants were less pronounced, resulting in the enhancement of net MeHg formation. The abundance of hgcA and merB genes suggested that Hg-methylating and MeHg-demethylating microbiomes responded differently to DOM treatments. Specific DOM components (e.g., aromatic proteins and soluble microbial byproducts) were positively correlated with both methylation rate constants and the abundance of Hg-methylating microbiomes. Our results highlight that the DOM composition influences the Hg methylation and MeHg demethylation differently and should be incorporated into future Hg risk assessments in aquatic ecosystems.

Modeling cosmological perturbations of thermal inflation

We consider a simple system consisting of matter, radiation and vacuum components to model the impact of thermal inflation on the evolution of primordial perturbations. The vacuum energy magnifies the primordial modes entering the horizon before its domination, making them potentially observable, and the resulting transfer function reflects the phase changes and energy contents. To determine the transfer function, we follow the curvature perturbation from well outside the horizon during radiation domination to well outside the horizon during vacuum domination and evaluate it on a constant radiation density hypersurface, as is appropriate for the case of thermal inflation. The shape of the transfer function is determined by the ratio of vacuum energy to radiation at matter-radiation equality, which we denote by , and has two characteristic scales, and , corresponding to the horizon sizes at matter radiation equality and the beginning of the inflation, respectively. If , the Universe experiences radiation, matter and vacuum domination eras and the transfer function is flat for , oscillates with amplitude for and oscillates with amplitude 1 for . For , the matter domination era disappears, and the transfer function reduces to being flat for and oscillating with amplitude 1 for .

Effects of in-utero personal exposure to PM2.5 sources and components on birthweight

In-utero exposure to fine particulate matter (PM2.5) and specific sources and components of PM2.5 have been linked with lower birthweight. However, previous results have been mixed, likely due to heterogeneity in sources impacting PM2.5 and due to measurement error from using ambient data. Therefore, we investigated the effect of PM2.5 sources and their high-loading components on birthweight using data from 198 women in the 3rd trimester from the MADRES cohort 48-h personal PM2.5 exposure monitoring sub-study. The mass contributions of six major sources of personal PM2.5 exposure were estimated for 198 pregnant women in the 3rd trimester using the EPA Positive Matrix Factorization v5.0 model, along with their 17 high-loading chemical components using optical carbon and X-ray fluorescence approaches. Single- and multi-pollutant linear regressions evaluated the association between personal PM2.5 sources/components and birthweight, adjusting for gestational age, maternal age, race, infant sex, parity, diabetes status, temperature, maternal education, and smoking history. Participants were predominately Hispanic (81%), with a mean (SD) gestational age of 39.1 (1.5) weeks and age of 28.2 (6.0) years. Mean birthweight was 3295.8 g (484.1) and mean PM2.5 exposure was 21.3 (14.4) µg/m3. A 1 SD increase in the mass contribution of the fresh sea salt source was associated with a 99.2 g decrease in birthweight (95% CI − 197.7, − 0.6), and aged sea salt was associated with a 70.1 g decrease in birthweight (95% CI − 141.7, 1.4). Magnesium, sodium, and chlorine were associated with lower birthweight, which remained after adjusting for PM2.5 mass. This study found evidence that major sources of personal PM2.5 including fresh and aged sea salt were negatively associated with birthweight, with the strongest effect on birthweight from Na and Mg. The effect of crustal and fuel oil sources differed by infant sex with negative associations seen in boys compared to positive associations in girls.

Unification: Emergent universe followed by inflation and dark epochs from multi-field theory

A two scalar field model that incorporates non Riemannian Measures of integration or usually called Two Measures Theory (TMT) is introduced, in order to unify the early and present universe. In the Einstein frame a K-essence is generated and as a consequence for the early universe, we can have a Non Singular Emergent universe followed by Inflation and for the present universe dark epochs with consistent generation of dark energy (DE), dark matter (DM) and stiff matter. The scale invariance is introduced and then is spontaneously broken from the integration of the degrees of freedom associated with the modified measures. The resulting effective potentials and K-essence in the Einstein frame produce three flat regions corresponding to the different epochs mentioned before. For the first flat region we can associate an emergent and an inflationary universe. Here for a parameter-space region this flat plateau possesses a non singular stable emergent universe solution which characterizes an initial epoch of evolution that precedes the inflationary scenario. Also assuming this first plateau, we study the inflation in the framework of the slow-roll approximation. In this scenario under the slow roll approximation we obtain a linear combination that is a constant. The corresponding cosmological perturbations in our model are determined and we also obtain the different constrains on the parameter-space from the Planck data.In the following flat region DE and also the DM, which does not need to be introduced separately, it is instead a result of a K-essence induced by the multi measures, multi field theory. Also stiff matter component is automatically generated from the K-essence theory from two scalar fields. From the perturbative analysis associated to the perturbation solution of background, we find a correlation between the two scalars. Besides, we obtain that our model during the dark epoch has a behavior of tracking freezing model.

Effects of Organic Fertilizers with Different Maturities on Soil Improvement and Soybean Yield

The maturity degree of organic fertilizer affects its application effect, but this application effect difference and the underlying reasons for it remain largely unclear. This study explored the effects of cattle manure compost with different maturities on soybean yield, soil physicochemical properties, and biological properties, and the underlying reasons for the differences in the application effects of organic fertilizers with different maturities. The results showed that the T21d treatment (GI = 62.5%, germination index) had the optimal effect on increasing soybean yield, and its effect on improving basic soil physicochemical properties, active organic matter components, enzyme activity, and microbial diversity was the most obvious. Compared with the control (CK), the soybean yield was increased by 15.1% under T21d treatment, and the soil organic matter (OM), alkali-hydrolyzed nitrogen (AN), available phosphorus (AP), and available potassium (AK) contents were increased by 29.9%, 25.0%, 22.2%, and 8.4%, respectively; the dissolved organic matter (DOM), extractable humus (HE), humic acid (HA), and fulvic acid (FA) contents in the soil were increased by 96.5%, 22.6%, 16.7%, and 30.6%, respectively; and the activities of soil phosphatase, neutral protease, urease, and cellulase were increased by 45.4%, 164.1%, 33.9%, and 128.9%, respectively. However, the fertilizer efficiency under the T28d, T45d, and T60d treatments with high-maturity organic fertilizers was lower than that under T21d. In general, the appropriate maturity of organic fertilizers has a positive effect on soil improvement and yield increase, but the excessive maturity of organic fertilizers reduces their application effects.

Construction of chitosan modified cationic lipid droplet emulsions for high-value microalgae harvesting

To reduce the risk of microalgae biomass and environmental contamination, a natural cationic lipid droplet emulsion has been constructed for harvesting microalgae. Using three different microalgae strains (Chlorella vulgaris, Scenedesmus quadricauda and Spirulina platensis), the present work studied the influence of lipid droplet dosage, chitosan concentration, pH on harvesting efficiency, and then the flotation behavior was analyzed by zeta potentials, floc size distribution, algal organic matter component, attenuated total reflectance Fourier transform infrared spectrometer and microscopic observation. The XDLVO theory was used to explain the attachment behavior during the flotation process. The experimental results showed that the maximum harvesting efficiency for two green microalgae strains was over 95% at pH 7, while the optimal dosage and ratio of lipid droplet and chitosan were depended on the microalgae species. The maximum harvesting efficiency for Spirulina platensis was less than 70% since the high salinity of growth medium weakened the bridging and netting ability of chitosan. The mechanism of capturing microalgae by the ballasting agents was mainly physical electrostatic attraction, bridging and netting. In addition, the changes of microalgae components before and after harvesting were less than 5%, indicating this method would not affect the downstream application of microalgae biomass.

Assessing PROSPECT performance on aquatic plant leaves

PROSPECT is the most widely used optical leaf model for a wide range of remote sensing applications on vegetation and has been developed and parameterised based on empirical data measured almost exclusively on terrestrial plant leaves. As aquatic plants differ substantially from terrestrial plants in leaf morphology and physiology, the validity of the relationships underlying PROSPECT in aquatic plants needs to be verified empirically. To this end, we compiled a comprehensive dataset of leaf spectra and biochemical-structural parameters sampled along a water affinity gradient, including floating and emergent hydrophytes, helophytes and riparian species, and terrestrial plants. In parallel, we designed a multidimensional experiment to explore the performance of PROSPECT across different groups and to characterise sources of modelling error, focusing on aquatic plants. Our results showed that estimates of most leaf parameters from PROSPECT inversions diverged increasingly from measured traits when moving from terrestrial to aquatic species. The suboptimal performance of PROSPECT on aquatic plants appears to be driven by three main factors: difficulties in disentangling leaf dry matter components (particularly proteins), unresolved issues related to the overlap of primary and secondary pigment mixtures and absorption, and the peculiarities of internal leaf structure (i.e. the presence of ‘aerenchyma’). These findings highlight the need for careful preliminary evaluation of the applicability and limitations of PROSPECT when applied to vegetation types that differ significantly from the typical terrestrial trees and grasses used for model calibration, including aquatic plants. Such evaluation should be preferably based on empirical data covering natural heterogeneity, so that future applications of remote sensing for mapping aquatic and wetland vegetation characteristics can be improved in terms of robustness and transferability.

Comparative Hygienic Assessment of the Composition of Ash and Dust Fractions in Ambient Air of the Area Affected by Emissions from a Thermal Power Station: Improving the Accuracy of Human Health Risk Assessment

Introduction: The relevance of the study is determined by a great number of functioning thermal power stations that operate using solid fuels (40 %) and are a source of ambient air pollution posing human health risks. Objective: A comparative hygienic assessment of the component, disperse, and morphological composition of fly ash and airborne particles in the area surrounding a coal-fired power station for the purpose of increasing the accuracy of human health risk assessment. Materials and methods: We have used unified and approved methods for hygienic assessment of ambient air quality; hazard identification and health risk assessment; scanning electron microscopy and micro-X-ray fluorescence spectroscopy of component, disperse, and morphological structure of fly ash and airborne particulate matter. Results and discussion: Large coal-fired thermal power plants emit about 36 chemicals. Over 59 % of brown coal ash particles are calcium, magnesium, iron, silicon, aluminum, sodium, potassium, sulfur, and phosphorus compounds. Particles found in fly ash and ambient air of the surrounding area have similar components and dispersion, are predominantly less than 10 µm in diameter with the sphericity index ranging from 0.4 to 1.0. Maximum allowable concentrations (MAC) of seven chemicals are exceeded in the study area: up to 3.3 single MAC, up to 1.4 average daily MAC, and up to 1.5 average annual MAC, with the estimated contribution of the thermal power stations of about 40 %. We have also established increased non-carcinogenic health risks with the dust fractions alone generating risk levels as high as 5.5 HQac, 2.4 HQch, and 6.9 HIch, which are rated as “high” and “alerting”. Identified solid particles (aluminum, magnesium, calcium, etc.) are more significant risk factors compared to unidentified particulate matter and can cause respiratory and circulatory diseases, diseases of the eye, etc., which requires their quantification. These chemicals are not included in air emissions inventory lists and are, therefore, not monitored. As a result, health risks posed by economic activities of thermal power stations may be underestimated.

Spatiotemporal Analysis of Ozone Concentration Using Semi-Functional Partial Linear Models

As weather warms up in China, ozone pollution rises to the top of the list of air pollutants. In this research, we examine the spatiotemporal variability of particulate matter components using contemporary functional data analysis techniques. The technique models the yearly pollutant profiles to describe their dynamic behavior over time and location. These cutting-edge methods offer dimension reduction for better data display and permit us to forecast annual profiles for locations and years for which data are lacking. In order to accurately estimate hourly ozone concentrations for 12 stations in China over two years (2015-2016), this study set out to showcase the best prediction models currently available. To accurately predict Ozone concentration, several methods are used, including Kernel Functional Classical Estimation (KFCE), Kernel Functional Quantile estimation (KFQE), Semi-Partial Linear Functional Classical Estimation (SPLFCE), Semi-Partial Linear Functional Quantile Estimation (SPLFQE), and Semi-Partial Linear Functional Expectile Estimation (SPLFEE). These functional models were chosen based on their ability to establish a forecast region with a given level of confidence. In terms of prediction accuracy, we may conclude that the Semi-Partial linear models outperform conventional models.

Comparison of Biological Activities and Protective Effects on PAH-Induced Oxidative Damage of Different Coffee Cherry Pulp Extracts.

Polycyclic aromatic hydrocarbons (PAHs) are the main toxic components of ambient air particulate matter (PM), causing oxidative damage to the skin and ultimately resulting in skin aging. This study was conducted to determine the anti-oxidant, anti-aging properties and protective effects of the extracts of coffee cherry pulp (Coffea arabica L.), which is a by-product of the coffee industry, against the oxidative damage induced by PAH exposure in human epidermal keratinocytes (HaCaT). Three different techniques were used to extract the coffee cherry pulp: maceration, Soxhlet and ultrasonication to obtain CCM, CCS and CCU extract, respectively, which were then compared to investigate the total phenolic content (TPC) and total flavonoid content (TFC). The chemical compositions were identified and quantified using high-performance liquid chromatography (HPLC). The results demonstrated that Soxhlet could extract the highest content of chlorogenic acid, caffeine and theophylline. CCS showed the significantly highest TPC (324.6 ± 1.2 mg GAE/g extract), TFC (296.8 ± 1.2 mg QE/g extract), anti-radical activity against DPPH free radicals (98.2 ± 0.8 µM Trolox/g extract) and lipid peroxidation inhibition (136.6 ± 6.2 µM Trolox/g extract). CCS also showed the strongest anti-aging effects based on collagenase, elastase, hyaluronidase and tyrosinase inhibitory enzymes. In addition, CCS can protect human keratinocyte cells from PAH toxicity by increasing the cellular anti-oxidant capacity. This study suggests that CCS has the potential to be used as a cosmetic material that helps alleviate skin damage caused by air pollution.

A novel tool for tracing water sources of streamflow in a mixed land-use catchment

Tracing water sources of streamflow in a mixed land-use catchment is critical for predicting pollutant emissions from various human activities to streams but remains a major challenge. A rain event based field monitoring study was conducted in the Jieliu catchment located in the hilly area of central Sichuan Province, southwest China. The ratio of the maximum fluorescence intensities (Fmax) of the two humic-like dissolved organic matter (DOM) components at excitation/emission wavelengths of 255 (315)/415 nm (component 1; C1) and 260 (375)/480 nm (component 2; C2) was proposed as a tracer for quantifying streamflow water sources. Satisfactory performance of using the Fmax(C1)/Fmax(C2) ratio in hydrograph separation of streamflow at the outlet of a forest sub-catchment was verified by through comparison with the hydrograph separation results based on δ18O data. The Fmax(C1)/Fmax(C2) ratio was then applied to estimate the contributions of rainwater and pre-event water sources under different land use types to the streamflow in an agro-forest sub-catchment and the entire catchment. The hydrograph separation results using the Fmax(C1)/Fmax(C2) ratio can be used to support the optimization of water resource management and the quantification of pollutant loadings from major water sources to streams at the catchment scale.

Single-species dinoflagellate cyst carbon isotope fractionation in core-top sediments: environmental controls, CO2 dependency and proxy potential

Abstract. Sedimentary bulk organic matter and various molecular organic components exhibit strong CO2-dependent carbon isotope fractionation relative to dissolved inorganic carbon sources. This fractionation (εp) has been employed as a proxy for paleo-pCO2. Yet, culture experiments indicate that CO2-dependent εp is highly specific at genus and even species level, potentially hampering the use of bulk organic matter and non-species-specific organic compounds. In recent years, significant progress has been made towards a CO2 proxy using controlled growth experiments with dinoflagellate species, also showing highly species-specific εp values. These values were, however, based on motile specimens, and it remains unknown whether these relations also hold for the organic-walled resting cysts (dinocysts) produced by these dinoflagellate species in their natural environment. We here analyze dinocysts isolated from core tops from the Atlantic Ocean and Mediterranean Sea, representing several species (Spiniferites elongatus, S. (cf.) ramosus, S. mirabilis, Operculodinium centrocarpum sensu Wall and Dale (1966) (hereafter referred to as O. centrocarpum) and Impagidinium aculeatum) using laser ablation–nano-combustion–gas-chromatography–isotope ratio mass spectrometry (LA/nC/GC-IRMS). We find that the dinocysts produced in the natural environment are all appreciably more 13C-depleted compared to the cultured motile dinoflagellate cells, implying higher overall εp values, and, moreover, exhibit large isotope variability. Where several species could be analyzed from a single location, we often record significant differences in isotopic variance and offsets in mean δ13C values between species, highlighting the importance of single-species carbon isotope analyses. The most geographically expanded dataset, based on O. centrocarpum, shows that εp correlates significantly with various environmental parameters. Importantly, O. centrocarpum shows a CO2-dependent εp above ∼ 240 µatm pCO2. Similar to other marine autotrophs, relative insensitivity at low pCO2 is in line with active carbon-concentrating mechanisms at low pCO2, although we here cannot fully exclude that we partly underestimated εp sensitivity at low pCO2 values due to the relatively sparse sampling in that range. Finally, we use the relation between εp and pCO2 in O. centrocarpum to propose a first pCO2 proxy based on a single dinocyst species.

Generating fuzzy dark matter droplets

This research aims to explore the possibility of constructing black hole (BH) surrounded by fuzzy dark matter (DM) haloes, based on the Einasto density profile. Furthermore, the study offers the possibility of including DM as the matter component making up the BH and also presents a generalization of the non-commutative mini BH models. We describe how the coupling of the Einasto profile with an anisotropic stress–energy tensor gives rise to different BH solutions corresponding to each value of the Einasto index and the rescaled mass parameter. The assumption of de Sitter-type equation of state (EOS), i.e., ρ=−pr, offers the possibility of constructing BH solution or a fuzzy self-gravitational DM droplet based on the values of the mass parameter. However, in the case of a non-local EOS, the corresponding structure can be a self-gravitational fuzzy DM droplet with negative radial pressure. Finally, we consider the possibility of BHs originating from DM existing in galactic centers. Mainly, we examine whether such types of BHs could possibly serve as the central objects within galaxies.

Insight into the dynamics of dissolved organic matter components under latitude change perturbation

Dissolved organic matter (DOM) which can help the transportation of nutrients and pollutants plays essential role in the aquatic ecosystems. However, the dynamics of individual DOM component under the change of latitude have not been elucidated to date. The composition and dynamics of DOM were assessed in this study. Two individual parallel factor analysis (PARAFAC) components were found in each sampling site in Heilongjiang. To further characterize the inner change of the identified PARAFAC components, two-latitude correlation spectroscopy (2DCOS) technique was applied to the excitation loadings data. Interestingly, not all the fluorophore in a PARAFAC component change in the same direction as the overall change of a component. From upstream to downstream, the peak A1 in PARAFAC component C1 showed a downward trend, but peak A2 presented an upward trend. In PARAFAC component C2, the peak T2 and peak T3 showed an inverse changing trend under latitude perturbation. Furthermore, basic nutrients parameters in Heilongjiang were also characterized in each sampling sites. The relationships between DOM and nutrients showed that component C1 made a significant contribution to chemical oxygen demand (COD) and biochemical oxygen demand (BOD5). The evolutions of DOM peak A1 and peak A2 were accompanied by the changing of Total phosphorus (TP). The findings in this study could make a contribution to explore the fate of DOM in high humic-like substance containing river.

Penggunaan Lembar Kegiatan Peserta Didik Materi Mikroalga sebagai Sumber Belajar Biologi

Student activity sheets are one of the Biology learning resource materials that are in great demand by students and the material delivered is microalgae is one of the components of the subject matter that can be used in the preparation of ecosystems contained in aquatic ecosystems that can be a source of student learning. Sourced from environmental aspects around Badur Beach, a sheet of activities for students in the microalgae practicum module was compiled. This research method uses descriptive qualitative by using data triangulation, namely observation, interviews, and documentation of the results of documentation written in the form of tables as one of the indicators in measuring the implementation of learning in the form of practicum in the classroom. The data collection instruments used are validity and response questionnaires. The sample in this study was 32 students in grade X of SMAN 3 Pamekasan and one biology teacher. The results showed that there is a lack of connection between understanding basic concepts and basic understanding of science in the context of everyday life. Teachers in learning biology SMA still do not use the environment as a learning resource in practicum learning in biology subjects at SMAN 3 Pamekasan. From these problems, one way to relate learning material to the context of everyday life is to do a practicum. Through simple practicum activities, students are directly expected to see real symptoms that are also related to the concept of the lesson, both natural conditions and conditions carried out through experiments.

Adsorption and thermal stability of dissolved organic matter on Ca- and Mg-exchanged montmorillonite: Implications for persistence in soils and sediments

Dissolved organic matter (DOM) represents a vital and highly dynamic component of organic matter in the environment. Despite its significance, there is still limited knowledge regarding how different base cations and chemical conditions influence the preservation of complex natural DOM through adsorption. This study aimed to investigate the adsorption of natural DOM onto montmorillonite (Mt) by systematically exploring the effects of exchanging cations (Ca2+ and Mg2+), pH levels (4 and 7), and DOM molecular weight (< 10, 10–100, and > 100 kDa) on the mechanisms and thermal stability of adsorbed DOM. To this end, we conducted a series of adsorption experiments, complemented by spectroscopic and thermal analyses. Our results revealed that lower pH and higher DOM molecular weight enhanced adsorption, with affinity for carbohydrate-like compounds. Notably, changes in d001 spacing and peak broadening indicated intercalation of DOM into the interlayer space of Mt, which was positively correlated with the amount of DOM adsorbed. Conversely, increased adsorption was found to negatively correlate with thermal stability. This was attributed to the prevalence of weaker DOM-DOM interactions occurring at higher DOM weight and lower pH, owing to reduced repulsion among protonated organic molecules, in contrast to stronger electrostatic interactions near the Mt surface that appeared to dominate at lower DOM weight and higher pH conditions. Intriguingly, no clear preference for DOM adsorption on Ca- or Mg-exchanged Mt was observed, suggesting similar efficiencies of these cations in stabilizing DOM through cation-bridging. Our findings provide significant insights into the mechanisms involved in mineral-organic associations and have implications for understanding the persistence of DOM in soils and sediments.

Predicted and observed changes in summertime biogenic and total organic aerosol in the southeast United States from 2001 to 2010

Biogenic secondary organic aerosol (bSOA) is a major component of atmospheric particulate matter (PM2.5) in the southeast United States especially during the summer, when emissions of biogenic volatile organic compound (VOCs) are high and emissions from anthropogenic sources enhance the formation of secondary particulate matter. In this work we test the hypothesis whether a chemical transport model (PMCAMx) that includes a detailed description of gas-phase chemistry, secondary organic aerosol (SOA) formation based on the volatility basis set (VBS), and interactions among compounds based on partitioning theory can predict organic aerosol (OA) concentrations that are consistent with the observed changes in OA in response to significant changes in anthropogenic emissions during the summers of 2001 and 2010. The model had good performance for OA for both periods and its predictions were consistent with the observed changes in both the urban and rural areas. The fractional error of OA predictions remained practically the same (0.41 and 0.44 at Chemical Speciation Network (CSN) sites and 0.40 to 0.41 at Interagency Monitoring of Protected Visual Environments (IMPROVE) sites in the summers of 2001 and 2010 respectively) in the two examined periods. The fractional bias of OA predictions increased from 0.10 to 0.22 at CSN sites and decreased from 0 to −0.09 at IMPROVE sites between the two periods. Average predicted bSOA concentrations in the southeast US did not change appreciably from the summer of 2001 to the summer of 2010, while the anthropogenic SOA decreased by 45%. As a result, the biogenic fraction of predicted total OA increased from 0.46 in 2001 to 0.63 in 2010. Partitioning effects due to reduced anthropogenic OA from 2001 resulted in 0.4 μg m−3 less biogenic OA on average in the southeast US in the summer of 2010. This was offset by biogenic SOA increases due to higher biogenic vapor emissions in the warmer 2010 summer. Removing the NOx-dependence of SOA formation yields resulted in higher fractional error and fractional bias at both CSN and IMPROVE sites in both summer periods, demonstrating the efficacy of the current formulation of SOA yields. The results of the analysis support the conclusion that a CTM that simulates NOx-dependent SOA chemistry and semivolatile partitioning of SOA material can consistently predict the observed changes in a region rich in biogenic VOCs and SOA.

Dark Matter in Fractional Gravity III: Dwarf Galaxies Kinematics

Recently, we put forward a framework where the dark matter (DM) component within virialized halos is subject to a non-local interaction originated by fractional gravity (FG) effects. In previous works, we demonstrated that such a framework can substantially alleviate the small-scale issues of the standard ΛCDM paradigm, without altering the DM mass profile predicted by N-body simulations, and retaining its successes on large cosmological scales. In this paper, we investigate further, to probe FG via the high-quality data of individual dwarf galaxies, by exploiting the rotation velocity profiles inferred from stellar and gas kinematic measurements in eight dwarf irregulars, and the projected velocity dispersion profiles inferred from the observed dynamics of stellar tracers in seven dwarf spheroidals and in the ultra-diffuse galaxy DragonFly 44. We find that FG can reproduce extremely well the rotation and dispersion curves of the analyzed galaxies, performing in most instances significantly better than the standard Newtonian setup.

Primordial black holes as near infrared background sources

Abstract The near infrared background (NIRB) is the collective light from unresolved sources observed in the band 1–10 $\rm{\mu m}$. The measured NIRB angular power spectrum on angular scales θ ≳ 1 arcmin exceeds by roughly two order of magnitudes predictions from known galaxy populations. The nature of the sources producing these fluctuations is still unknown. Here we test primordial black holes (PBHs) as sources of the NIRB excess. Considering PBHs as a cold dark matter (DM) component, we model the emission of gas accreting onto PBHs in a cosmological framework. We account for both accretion in the intergalactic medium (IGM) and in DM haloes. We self consistently derive the IGM temperature evolution, considering ionization and heating due to X-ray emission from PBHs. Besides ΛCDM, we consider a model that accounts for the modification of the linear matter power spectrum due to the presence of PBHs; we also explore two PBH mass distributions, i.e. a δ-function and a lognormal distribution. For each model, we compute the mean intensity and the angular power spectrum of the NIRB produced by PBHs with mass 1–$10^3~\rm M_{\odot}$. In the limiting case in which the entirety of DM is made of PBHs, the PBH emission contributes &amp;lt;1 per cent to the observed NIRB fluctuations. This value decreases to &amp;lt;0.1 per cent if current constraints on the abundance of PBHs are taken into account. We conclude that PBHs are ruled out as substantial contributors to the NIRB.