Positive matrix factorization on source apportionment for typical pollutants in different environmental media: a review

A bibliometric analysis of published papers with the key words "positive matrix factorization" and "source apportionment" in 'Web of Science', reveals that more than 1000 papers are associated with this research and that approximately 50% of these were produced in Asia. As a receptor-based model, positive matrix factorization (PMF) has been widely used for source apportionment of various environmental pollutants, such as persistent organic pollutants (POPs), heavy metals, volatile organic compounds (VOCs) as well as inorganic cations and anions in the last decade. In this review, based on the papers mainly from 2008 to 2018 that focused on source apportionment of pollutants in different environmental media, we provide a comparison and summary of the source categories of typical environmental pollutants, with a special focus on polycyclic aromatic hydrocarbons (PAHs), apportioned using PMF. Based on the statistical average, coal combustion and vehicular emission, are shown to be the two most common sources of PAHs, and contribute much more to emissions than other sources, such as biomass burning, biogenic sources and waste incineration. Heavy metals were mainly from agricultural activities, industrial and vehicular emissions and mining activities. Quantitative source apportionment on pollutants such as VOCs and particulate matter were also apportioned, showing a prominent contribution from fossil-fuel combustion. We conclude that, aside from natural sources, abatement strategies should be focused on changes in energy structure and industrial activities, especially in China. Source apportionment of typical POPs including polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), halogenated flame retardants (HFRs) and perfluorinated compounds (PFCs) is less comprehensive and further study is required

Occurrence, sources and seasonal variation of PM2.5 carbonaceous aerosols in a water level fluctuation zone in the Three Gorges Reservoir, China

Periodic water impoundment and seasonal flood events result in a 30 m water level fluctuation zone (WLFZ) in the Three Gorges Reservoir Region (TGRR), China. In order to assess the occurrence, sources and seasonal variation of airborne carbonaceous pollutants, a total of thirty-nine PM2.5 samples, twenty-two from August 2017 (summer: low water level ∼135m) and seventeen from January 2018 (winter: high water level ∼175m) were collected consecutively at a rural site in WLFZ in the TGRR. The results showed that OC, EC, char, soot, 16 PAHs and n-alkanes were higher in winter (mean: 9.17 μg/m3, 4.69 μg/m3, 4.25 μg/m3, 0.45 μg/m3, 19.8 ng/m3 and 210 ng/m3, respectively) than in summer (mean: 6.55 μg/m3, 1.70 μg/m3, 1.37 μg/m3, 0.32 μg/m3, 6.13 ng/m3 and 79.1 ng/m3, respectively). Compositional differences suggested air-soil/plant exchange as a source for 2-3-rings PAHs in summer and biomass burning for 4-5-rings in winter. Diagnostic ratios and PCA suggested more vehicular emission for PAHs in summer. Plant waxes contributed 18.2% and 26.2% of the n-alkanes in summer and winter, respectively, implying a relatively greater contribution from petroleum residues. The specific ratios and relative abundance of hopanes and steranes indicated mixed sources from both vehicle exhaust and petroleum residue; and petroleum residues contribute more steranes in summer compared with winter. As revealing basic information on the formation mechanism of carbonaceous aerosols, this study could contribute to a further understanding of their environmental geochemical behavior in the WLFZ of TGRR

``Fermi Liquid'' Shell Model Approach to Composite Fermion Excitation Spectra in Fractional Quantum Hall States

Numerical results for the energy spectra of $N$ electrons on a spherical surface are used as input data to determine the quasiparticle energies and the pairwise ``Fermi liquid'' interactions of composite Fermion (CF) excitations in fractional quantum Hall systems. The quasiparticle energies and their interactions are then used to determine the energy spectra, $E$ vs total angular momentum $L$, of states containing more than two quasiparticles. The qualitative agreement with the numerical results gives a remarkable new confirmation of the CF picture.Comment: LaTex, 4 pages, including 4 .eps-figures, to be appear in pr

Zooplankton Community Structure in Seagrass Ecosystem, Tongkaina Village, Bunaken Darat District, Manado City

This study aims to determine the type and community structure of zooplankton in the Tongkaina seagrass aquatic ecosystem. Sampling was carried out at 3 location points using plankton nets. Plankton net was drawn along 50 meters from the sea towards the beach. There are 14 genera of zooplankton in the morning and 17 genera in the afternoon. The total density of zooplankton in the morning was 0.064 individual/l , and in the afternoon 0.114 individual/l. The highest density of zooplankton in the morning is Limacina and in the afternoon, Calanus. The zooplankton Diversity Index (H ') in the morning is 2.5907 and in the afternoon is 2.7321, indicating that the diversity level is less diverse. Morning uniformity (e) zooplankton index was 0.5614 and in the afternoon 0.5267, showed that the distribution pattern of zooplankton was moderate. The zooplankton dominance (C) index in the morning was 0.0783 and in the afternoon 0.0720. This shows that there is no dominant genus. Water conditions fall into the good category due to the temperature, salinity, and pH that are quite stable and are still within the limits of feasibility for zooplankton life.    Keywords: Zooplankton, Community Structure, Seagrass, Tongkaina Waters.Keywords: Zooplankton, Community Structure, Seagrass, Tongkaina Waters  ABSTRAKPenelitian ini bertujuan untuk mengetahui jenis dan struktur komunitas zooplankton yang ada di ekosistem perairan lamun Tongkaina. Pengambilan sampel dilakukan pada 3 titik lokasi dengan menggunakan jaring plankton.Plankton net ditarik sepanjang 50 meter dari laut ke arah pantai. Terdapat 14 genus zooplankton pada waktu pagi dan 17 genus pada waktu sore. Kepadatan total zooplankton pada waktu pagi hari 0.064 ind/l dan sore hari 0.114 ind/l. Kepadatan relatif zooplankton yang tertinggi pada pagi hari yaitu Limacina dan pada sore hari yaitu Calanus. Adapun Indeks Keanekaragaman (H’) zooplankton pada pagi hari sebesar 2.5907 dan sore hari sebesar 2.7321, menunjukkan bahwa tingkat keanekaragaman kurang beragam. Indeks Keseragaman (e) zooplankton pada pagi hari sebesar 0.5614 dan pada sore hari 0.5267, menunjukkan bahwa pola sebaran zooplankton sedang. Indeks Dominansi (C) zooplankton pada waktu pagi hari sebesar 0.0783 dan sore hari 0.0720. Hal ini menunjukkan bahwa tidak ada genus yang dominan. Kondisi perairan masuk dalam kategori baik dikarenakan suhu, salinitas dan pH cukup stabil dan masih berada dalam batas kelayakan bagi kehidupan zooplankton.Kata kunci: Zooplankton, Struktur Komunitas, Lamun,  Perairan Tongkaina

HTSanalyzeR: an R/Bioconductor package for integrated network analysis of high-throughput screens

Motivation: High-throughput screens (HTS) by RNAi or small molecules are among the most promising tools in functional genomics. They enable researchers to observe detailed reactions to experimental perturbations on a genome-wide scale. While there is a core set of computational approaches used in many publications to analyze these data, a specialized software combining them and making them easily accessible has so far been missing

New results for the two neutrino double beta decay in deformed nuclei with angular momentum projected basis

Four nuclei which are proved to be $2\nu\beta\beta$ emitters ($^{76}$Ge, $^{82}$Se, $^{150}$Nd, $^{238}$U), and four suspected, due to the corresponding Q-values, to have this property ($^{148}$Nd, $^{154}$Sm, $^{160}$Gd, $^{232}$Th), were treated within a proton-neutron quasiparticle random phase approximation (pnQRPA) with a projected spherical single particle basis. The advantage of the present procedure over the ones using a deformed Woods Saxon or Nilsson single particle basis is that the actual pnQRPA states have a definite angular momentum while all the others provide states having only K as a good quantum number. The model Hamiltonian involves a mean field term yielding the projected single particle states, a pairing interaction for alike nucleons and a dipole-dipole proton-neutron interaction in both the particle-hole (ph) and particle-particle (pp) channels. The effect of nuclear deformation on the single beta strength distribution as well as on the double beta Gamow-Teller transition amplitude (M$_{{\rm GT}}$) is analyzed. The results are compared with the existent data and with the results from a different approach, in terms of the process half life T$_{1/2}$. The case of different deformations for mother and daughter nuclei is also presented.Comment: 45 pages, 13 figure

Demagnetization Protocols for Frustrated Interacting Nanomagnet Arrays

We report a study of demagnetization protocols for frustrated arrays of interacting single domain permalloy nanomagnets by rotating the arrays in a changing magnetic field. The most effective demagnetization is achieved by not only stepping the field strength down while the sample is rotating, but by combining each field step with an alternation in the field direction. By contrast, linearly decreasing the field strength or stepping the field down without alternating the field direction leaves the arrays with a larger remanent magnetic moment. These results suggest that non-monotonic variations in field magnitude around and below the coercive field are important for the demagnetization process.Comment: 12 pages, 4 figure

Dirac-Foldy term and the electromagnetic polarizability of the neutron

We reconsider the Dirac-Foldy contribution $\mu^2/m$ to the neutron electric polarizability. Using a Dirac equation approach to neutron-nucleus scattering, we review the definitions of Compton continuum ($\bar{\alpha}$), classical static ($\alpha^n_E$), and Schr\"{o}dinger ($\alpha_{Sch}$) polarizabilities and discuss in some detail their relationship. The latter $\alpha_{Sch}$ is the value of the neutron electric polarizability as obtained from an analysis using the Schr\"{o}dinger equation. We find in particular $\alpha_{Sch} = \bar{\alpha} - \mu^2/m$ , where $\mu$ is the magnitude of the magnetic moment of a neutron of mass $m$. However, we argue that the static polarizability $\alpha^n_E$ is correctly defined in the rest frame of the particle, leading to the conclusion that twice the Dirac-Foldy contribution should be added to $\alpha_{Sch}$ to obtain the static polarizability $\alpha^n_E$.Comment: 11 pages, RevTeX, to appear in Physical Review

Two loop electroweak corrections to Bˉ→Xsγ\bar B\rightarrow X_s\gamma and Bs0→μ+μ−B_s^0\rightarrow \mu^+\mu^- in the B-LSSM

The rare decays $\bar B\rightarrow X_s\gamma$ and $B_s^0\rightarrow \mu^+\mu^-$ are important to research new physics beyond standard model. In this work, we investigate two loop electroweak corrections to $\bar B\rightarrow X_s\gamma$ and $B_s^0\rightarrow \mu^+\mu^-$ in the minimal supersymmetric extension of the SM with local $B-L$ gauge symmetry (B-LSSM), under a minimal flavor violating assumption for the soft breaking terms. In this framework, new particles and new definition of squarks can affect the theoretical predictions of these two processes, with respect to the MSSM. Considering the constraints from updated experimental data, the numerical results show that the B-LSSM can fit the experimental data for the branching ratios of $\bar B\rightarrow X_s\gamma$ and $B_s^0\rightarrow \mu^+\mu^-$. The results of the rare decays also further constrain the parameter space of the B-LSSM.Comment: 33 pages, 9 figures, Published in EPJ