656 research outputs found

    Life cycle assessment of bacterial cellulose production

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    Purpose Bacterial cellulose (BC), obtained by fermentation, is an innovative and promising material with a broad spectrum of potential applications. Despite the increasing efforts towards its industrialization, a deeper understanding of the environmental impact related to the BC production process is still required. This work aimed at quantifying the environmental, health, and resource depletion impacts related to a production of BC. Methods An attributional life cycle assessment (LCA) was applied to a process design of production of BC, by static culture, following a cradle-to-gate approach. The LCA was modeled with GaBi Pro Software using the ReCiPe 2016 (H) methodology with environmental impact indicators at midpoint level. The functional unit was defined as 1 kg of BC (dry mass), in 138.8 kg of water. Results From the total used resources (38.9 ton/kg of BC), water is the main one (36.1 ton/kg of BC), most of which (98%) is returned to fresh waters after treatment. The production of raw materials consumed 17.8 ton of water/kg of BC, 13.8 ton/kg of BC of which was for the production of carton packaging, culture medium raw materials, and sodium hydroxide (for the washing of BC). The remaining consumed water was mainly for the fermentation (3.9 ton/kg) and downstream process (7.7 ton/kg). From the identified potential environmental impacts, the production of raw materials had the highest impact, mainly on Climate change, Fossil depletion, Human toxicity, non-cancer, and Terrestrial toxicity. The sodium dihydrogen phosphate production, used in the culture medium, showed the highest environmental impacts in Human toxicity, non-cancer and Terrestrial ecotoxicity, followed by corn syrup and carton production. The static culture fermentation and downstream process showed impact in Climate change and Fossil depletion. Conclusions Per se, the BC production process had a small contribution to the consumption of resources and environmental impact of the BC global life cycle.This study was supported by the Portuguese Foundation for Science and Technology (FCT) within the scope of the strate gic funding of UIDB/04469/2020 and UIDB/00511/2020 units and MultiBiorefinery project (SAICTPAC/0040/2015-POCI-01-0145- FEDER-016403). This study was also supported by The Navigator Company through the I&D no. 21874, “Inpactus-–Produtos e Tecno logias Inovadores a partir do Eucalipto”, funded through the European Regional Development Fund (ERDF) and the Programa Operacional Competitividade e Internacionalização (POCI) is greatly acknowl edged. The work by Belmira Neto was fnancially supported by Base Funding—UIDB/00511/2020 of the Laboratory for Process Engineer ing, Environment, Biotechnology and Energy—LEPABE—funded by national funds through the FCT/MCTES (PIDDAC).info:eu-repo/semantics/publishedVersio

    The Complexity of Marriage in Rural Ethiopia: Parental Transfers and Postmarital Residence Choices

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    This paper examines the relationship between parental transfers and post-marital residence of children in rural Ethiopia. We investigate whether asset transfers to children are an avenue which parents use to secure old age. We model post-marital residence and transfers simultaneously in a two-stage probit least squares estimation framework. We find a positive relationship between transfers and post-marital residence, a 10 proxy for old age support. Children who receive more assets are more likely to stay at birth place after marriage and vice versa. In conditions of scarce or lacking social security mechanisms, parents make strategic transfers to ensure better old age

    Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR

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    Simulation results for future measurements of electromagnetic proton form factors at \PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel pˉpe+e\bar p p \to e^+ e^- is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e.\textit{i.e.} pˉpπ+π\bar p p \to \pi^+ \pi^-, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance

    Observation and study of the decay J/ψϕηηJ/\psi\rightarrow\phi\eta\eta'

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    We report the observation and study of the decay J/ψϕηηJ/\psi\rightarrow\phi\eta\eta' using 1.3×1091.3\times{10^9} J/ψJ/\psi events collected with the BESIII detector. Its branching fraction, including all possible intermediate states, is measured to be (2.32±0.06±0.16)×104(2.32\pm0.06\pm0.16)\times{10^{-4}}. We also report evidence for a structure, denoted as XX, in the ϕη\phi\eta' mass spectrum in the 2.02.12.0-2.1 GeV/c2c^2 region. Using two decay modes of the η\eta' meson (γπ+π\gamma\pi^+\pi^- and ηπ+π\eta\pi^+\pi^-), a simultaneous fit to the ϕη\phi\eta' mass spectra is performed. Assuming the quantum numbers of the XX to be JP=1J^P = 1^-, its significance is found to be 4.4σ\sigma, with a mass and width of (2002.1±27.5±21.4)(2002.1 \pm 27.5 \pm 21.4) MeV/c2c^2 and (129±17±9)(129 \pm 17 \pm 9) MeV, respectively, and a product branching fraction B(J/ψηX)×B(Xϕη)=(9.8±1.2±1.7)×105\mathcal{B}(J/\psi\rightarrow\eta{}X)\times{}\mathcal{B}(X\rightarrow\phi\eta')=(9.8 \pm 1.2 \pm 1.7)\times10^{-5}. Alternatively, assuming JP=1+J^P = 1^+, the significance is 3.8σ\sigma, with a mass and width of (2062.8±13.1±7.2)(2062.8 \pm 13.1 \pm 7.2) MeV/c2c^2 and (177±36±35)(177 \pm 36 \pm 35) MeV, respectively, and a product branching fraction B(J/ψηX)×B(Xϕη)=(9.6±1.4±2.0)×105\mathcal{B}(J/\psi\rightarrow\eta{}X)\times{}\mathcal{B}(X\rightarrow\phi\eta')=(9.6 \pm 1.4 \pm 2.0)\times10^{-5}. The angular distribution of J/ψηXJ/\psi\rightarrow\eta{}X is studied and the two JPJ^P assumptions of the XX cannot be clearly distinguished due to the limited statistics. In all measurements the first uncertainties are statistical and the second systematic.Comment: 10 pages, 6 figures and 4 table

    Observation of ηcωω\eta_c\to\omega\omega in J/ψγωωJ/\psi\to\gamma\omega\omega

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    Using a sample of (1310.6±7.0)×106(1310.6\pm7.0)\times10^6 J/ψJ/\psi events recorded with the BESIII detector at the symmetric electron positron collider BEPCII, we report the observation of the decay of the (11S0)(1^1 S_0) charmonium state ηc\eta_c into a pair of ω\omega mesons in the process J/ψγωωJ/\psi\to\gamma\omega\omega. The branching fraction is measured for the first time to be B(ηcωω)=(2.88±0.10±0.46±0.68)×103\mathcal{B}(\eta_c\to\omega\omega)= (2.88\pm0.10\pm0.46\pm0.68)\times10^{-3}, where the first uncertainty is statistical, the second systematic and the third is from the uncertainty of B(J/ψγηc)\mathcal{B}(J/\psi\to\gamma\eta_c). The mass and width of the ηc\eta_c are determined as M=(2985.9±0.7±2.1)M=(2985.9\pm0.7\pm2.1)\,MeV/c2c^2 and Γ=(33.8±1.6±4.1)\Gamma=(33.8\pm1.6\pm4.1)\,MeV.Comment: 13 pages, 6 figure

    Search for the decay J/ψγ+invisibleJ/\psi\to\gamma + \rm {invisible}

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    We search for J/ψJ/\psi radiative decays into a weakly interacting neutral particle, namely an invisible particle, using the J/ψJ/\psi produced through the process ψ(3686)π+πJ/ψ\psi(3686)\to\pi^+\pi^-J/\psi in a data sample of (448.1±2.9)×106(448.1\pm2.9)\times 10^6 ψ(3686)\psi(3686) decays collected by the BESIII detector at BEPCII. No significant signal is observed. Using a modified frequentist method, upper limits on the branching fractions are set under different assumptions of invisible particle masses up to 1.2  GeV/c2\mathrm{\ Ge\kern -0.1em V}/c^2. The upper limit corresponding to an invisible particle with zero mass is 7.0×107\times 10^{-7} at the 90\% confidence level

    Measurement of proton electromagnetic form factors in e+eppˉe^+e^- \to p\bar{p} in the energy region 2.00-3.08 GeV

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    The process of e+eppˉe^+e^- \rightarrow p\bar{p} is studied at 22 center-of-mass energy points (s\sqrt{s}) from 2.00 to 3.08 GeV, exploiting 688.5~pb1^{-1} of data collected with the BESIII detector operating at the BEPCII collider. The Born cross section~(σppˉ\sigma_{p\bar{p}}) of e+eppˉe^+e^- \rightarrow p\bar{p} is measured with the energy-scan technique and it is found to be consistent with previously published data, but with much improved accuracy. In addition, the electromagnetic form-factor ratio (GE/GM|G_{E}/G_{M}|) and the value of the effective (Geff|G_{\rm{eff}}|), electric (GE|G_E|) and magnetic (GM|G_M|) form factors are measured by studying the helicity angle of the proton at 16 center-of-mass energy points. GE/GM|G_{E}/G_{M}| and GM|G_M| are determined with high accuracy, providing uncertainties comparable to data in the space-like region, and GE|G_E| is measured for the first time. We reach unprecedented accuracy, and precision results in the time-like region provide information to improve our understanding of the proton inner structure and to test theoretical models which depend on non-perturbative Quantum Chromodynamics

    First observations of hch_c \to hadrons

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    Based on (4.48±0.03)×108(4.48 \pm 0.03) \times 10^{8} ψ(3686)\psi(3686) events collected with the BESIII detector, five hch_c hadronic decays are searched for via process ψ(3686)π0hc\psi(3686) \to \pi^0 h_c. Three of them, hcppˉπ+πh_c \to p \bar{p} \pi^+ \pi^-, π+ππ0\pi^+ \pi^- \pi^0, and 2(π+π)π02(\pi^+ \pi^-) \pi^0 are observed for the first time, with statistical significances of 7.4σ\sigma, 4.9σ4.9\sigma, and 9.1σ\sigma, and branching fractions of (2.89±0.32±0.55)×103(2.89\pm0.32\pm0.55)\times10^{-3}, (1.60±0.40±0.32)×103(1.60\pm0.40\pm0.32)\times10^{-3}, and (7.44±0.94±1.56)×103(7.44\pm0.94\pm1.56)\times10^{-3}, respectively, where the first uncertainties are statistical and the second systematic. No significant signal is observed for the other two decay modes, and the corresponding upper limits of the branching fractions are determined to be B(hc3(π+π)π0)<8.7×103B(h_c \to 3(\pi^+ \pi^-) \pi^0)<8.7\times10^{-3} and B(hcK+Kπ+π)<5.8×104B(h_c \to K^+ K^- \pi^+ \pi^-)<5.8\times10^{-4} at 90% confidence level.Comment: 17 pages, 16 figure

    Evidence for the decays of Λc+Σ+η\Lambda^+_{c}\to\Sigma^+\eta and Σ+η\Sigma^+\eta^\prime

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    We study the hadronic decays of Λc+\Lambda_{c}^{+} to the final states Σ+η\Sigma^{+}\eta and Σ+η\Sigma^+\eta^\prime, using an e+ee^{+}e^{-} annihilation data sample of 567 pb1^{-1} taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII collider. We find evidence for the decays Λc+Σ+η\Lambda_{c}^{+}\rightarrow\Sigma^{+}\eta and Σ+η\Sigma^+\eta^\prime with statistical significance of 2.5σ2.5\sigma and 3.2σ3.2\sigma, respectively. Normalizing to the reference decays Λc+Σ+π0\Lambda_c^+\to\Sigma^+\pi^0 and Σ+ω\Sigma^+\omega, we obtain the ratios of the branching fractions B(Λc+Σ+η)B(Λc+Σ+π0)\frac{{\mathcal B}(\Lambda_c^+\to\Sigma^+\eta)}{{\mathcal B}(\Lambda_c^+\to\Sigma^+\pi^0)} and B(Λc+Σ+η)B(Λc+Σ+ω)\frac{{\mathcal B}(\Lambda_c^+\to\Sigma^+\eta^\prime)}{{\mathcal B}(\Lambda_c^+\to\Sigma^+\omega)} to be 0.35±0.16±0.030.35 \pm 0.16 \pm 0.03 and 0.86±0.34±0.070.86 \pm 0.34 \pm 0.07, respectively. The upper limits at the 90\% confidence level are set to be B(Λc+Σ+η)B(Λc+Σ+π0)<0.58\frac{{\mathcal B}(\Lambda_c^+\to\Sigma^+\eta)}{{\mathcal B}(\Lambda_c^+\to\Sigma^+\pi^0)}<0.58 and B(Λc+Σ+η)B(Λc+Σ+ω)<1.2\frac{{\mathcal B}(\Lambda_c^+\to\Sigma^+\eta^\prime)}{{\mathcal B}(\Lambda_c^+\to\Sigma^+\omega)}<1.2. Using BESIII measurements of the branching fractions of the reference decays, we determine B(Λc+Σ+η)=(0.41±0.19±0.05)%\mathcal B({\Lambda_{c}^{+}\rightarrow\Sigma^{+}\eta})=(0.41\pm0.19\pm0.05)\% (<0.68%<0.68\%) and B(Λc+Σ+η)=(1.34±0.53±0.21)%\mathcal B({\Lambda_{c}^{+}\rightarrow\Sigma^{+}\eta'})=(1.34\pm0.53\pm0.21)\% (<1.9%<1.9\%). Here, the first uncertainties are statistical and the second systematic. The obtained branching fraction of Λc+Σ+η\Lambda_c^+\to\Sigma^+\eta is consistent with the previous measurement, and the branching fraction of Λc+Σ+η\Lambda_{c}^{+}\rightarrow\Sigma^{+}\eta^{\prime} is measured for the first time.Comment: Accepted by Chin. Phys. C : Chin. Phys. C 43, 083002, (2019

    Precise Measurements of Branching Fractions for Ds+D_s^+ Meson Decays to Two Pseudoscalar Mesons

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    We measure the branching fractions for seven Ds+D_{s}^{+} two-body decays to pseudo-scalar mesons, by analyzing data collected at s=4.1784.226\sqrt{s}=4.178\sim4.226 GeV with the BESIII detector at the BEPCII collider. The branching fractions are determined to be B(Ds+K+η)=(2.68±0.17±0.17±0.08)×103\mathcal{B}(D_s^+\to K^+\eta^{\prime})=(2.68\pm0.17\pm0.17\pm0.08)\times10^{-3}, B(Ds+ηπ+)=(37.8±0.4±2.1±1.2)×103\mathcal{B}(D_s^+\to\eta^{\prime}\pi^+)=(37.8\pm0.4\pm2.1\pm1.2)\times10^{-3}, B(Ds+K+η)=(1.62±0.10±0.03±0.05)×103\mathcal{B}(D_s^+\to K^+\eta)=(1.62\pm0.10\pm0.03\pm0.05)\times10^{-3}, B(Ds+ηπ+)=(17.41±0.18±0.27±0.54)×103\mathcal{B}(D_s^+\to\eta\pi^+)=(17.41\pm0.18\pm0.27\pm0.54)\times10^{-3}, B(Ds+K+KS0)=(15.02±0.10±0.27±0.47)×103\mathcal{B}(D_s^+\to K^+K_S^0)=(15.02\pm0.10\pm0.27\pm0.47)\times10^{-3}, B(Ds+KS0π+)=(1.109±0.034±0.023±0.035)×103\mathcal{B}(D_s^+\to K_S^0\pi^+)=(1.109\pm0.034\pm0.023\pm0.035)\times10^{-3}, B(Ds+K+π0)=(0.748±0.049±0.018±0.023)×103\mathcal{B}(D_s^+\to K^+\pi^0)=(0.748\pm0.049\pm0.018\pm0.023)\times10^{-3}, where the first uncertainties are statistical, the second are systematic, and the third are from external input branching fraction of the normalization mode Ds+K+Kπ+D_s^+\to K^+K^-\pi^+. Precision of our measurements is significantly improved compared with that of the current world average values
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