Precision constraints on radiative neutrino decay with CMB spectral distortion

We investigate the radiative decay of the cosmic neutrino background, and its impact on the spectrum of the cosmic microwave background (CMB) that is known to be a nearly perfect black body. We derive exact formulae for the decay of a heavier neutrino into a lighter neutrino and a photon, $\nu_j \to \nu_i + \gamma$, and of absorption as its inverse, $\nu_i + \gamma \to \nu_j$, by accounting for the precise form of the neutrino momentum distribution. Our calculations show that if the neutrinos are heavier than $\mathcal O(0.1)$ eV, the exact formulae give results that differ by $\sim$50%, compared with approximate ones where neutrinos are assumed to be at rest. We also find that spectral distortion due to absorption is more important for heavy neutrino masses (by a factor of $\sim$10 going from a neutrino mass of 0.01 eV to 0.1 eV). By analyzing the CMB spectral data measured with COBE-FIRAS, we obtain lower limits on the neutrino lifetime of $\tau_{12} \gtrsim 4 \times 10^{21}$ s (95% C.L.) for the smaller mass splitting and $\tau_{13} \sim \tau_{23} \gtrsim 10^{19}$ s for the larger mass splitting. These represent up to one order of magnitude improvement over previous CMB constraints. With future CMB experiments such as PIXIE, these limits will improve by roughly 4 orders of magnitude. This translates to a projected upper limit on the neutrino magnetic moment (for certain neutrino masses and decay modes) of $\mu_\nu < 3 \times 10^{-11}\, \mu_B$, where $\mu_B$ is the Bohr magneton. Such constraints would make future precision CMB measurements competitive with lab-based constraints on neutrino magnetic moments.Comment: 14 pages, 9 figures. v2: Added a number of references and clarifications. Matches version published in PR

Quantification of carbon monoxide emissions from African cities using TROPOMI

Carbon monoxide (CO) is an air pollutant that plays an important role in atmospheric chemistry and is mostly emitted by forest fires and incomplete combustion in, for example, road transport, residential heating, and industry. As CO is co-emitted with fossil fuel CO2 combustion emissions, it can be used as a proxy for CO2. Following the Paris Agreement, there is a need for independent verification of reported activity-based bottom-up CO2 emissions through atmospheric measurements. CO can be observed daily at a global scale with the TROPOspheric Monitoring Instrument (TROPOMI) satellite instrument with daily global coverage at a resolution down to 5.5 × 7 km2. To take advantage of this unique TROPOMI dataset, we develop a cross-sectional flux-based emission quantification method that can be applied to quantify emissions from a large number of cities, without relying on computationally expensive inversions. We focus on Africa as a region with quickly growing cities and large uncertainties in current emission estimates. We use a full year of high-resolution Weather Research and Forecasting (WRF) simulations over three cities to evaluate and optimize the performance of our cross-sectional flux emission quantification method and show its reliability down to emission rates of 0.1 Tg CO yr−1. Comparison of the TROPOMI-based emission estimates to the Dynamics–Aerosol–Chemistry–Cloud Interactions in West Africa (DACCIWA) and Emissions Database for Global Atmospheric Research (EDGAR) bottom-up inventories shows that CO emission rates in northern Africa are underestimated in EDGAR, suggesting overestimated combustion efficiencies. We see the opposite when comparing TROPOMI to the DACCIWA inventory in South Africa and Côte d'Ivoire, where CO emission factors appear to be overestimated. Over Lagos and Kano (Nigeria) we find that potential errors in the spatial disaggregation of national emissions cause errors in DACCIWA and EDGAR respectively. Finally, we show that our computationally efficient quantification method combined with the daily TROPOMI observations can identify a weekend effect in the road-transport-dominated CO emissions from Cairo and Algiers.</p

Bistability of Mitochondrial Respiration Underlies Paradoxical Reactive Oxygen Species Generation Induced by Anoxia

Increased production of reactive oxygen species (ROS) in mitochondria underlies major systemic diseases, and this clinical problem stimulates a great scientific interest in the mechanism of ROS generation. However, the mechanism of hypoxia-induced change in ROS production is not fully understood. To mathematically analyze this mechanism in details, taking into consideration all the possible redox states formed in the process of electron transport, even for respiratory complex III, a system of hundreds of differential equations must be constructed. Aimed to facilitate such tasks, we developed a new methodology of modeling, which resides in the automated construction of large sets of differential equations. The detailed modeling of electron transport in mitochondria allowed for the identification of two steady state modes of operation (bistability) of respiratory complex III at the same microenvironmental conditions. Various perturbations could induce the transition of respiratory chain from one steady state to another. While normally complex III is in a low ROS producing mode, temporal anoxia could switch it to a high ROS producing state, which persists after the return to normal oxygen supply. This prediction, which we qualitatively validated experimentally, explains the mechanism of anoxia-induced cell damage. Recognition of bistability of complex III operation may enable novel therapeutic strategies for oxidative stress and our method of modeling could be widely used in systems biology studies

Energietransitie begint in de regio : Rotterdam, Texel en Energy Valley onder de loep

Het doel van het onderzoek is om te evalueren hoe verduurzaming van de energievoorziening uitpakt in regionale praktijken en daaruit lessen te trekken voor het rijksbeleid. De volgende onderzoeksvragen staan daarbij centraal: 1. Hoe krijgt de regionale energietransitie vorm? – Hoe vindt regionale netwerkvorming tussen partijen plaats? – Welke regionale initiatieven zijn er voor besparing, hernieuwbare bronnen en eindige bronnen (de energieladder) en in hoeverre komen ze van de grond? – Welke netwerksturing, economische en juridische sturing oefent het Rijk hierop uit? 2. Welke lessen voor het rijksbeleid zijn hieruit te trekken

Energietransitie begint in de regio : Rotterdam, Texel en Energy Valley onder de loep

Het doel van het onderzoek is om te evalueren hoe verduurzaming van de energievoorziening uitpakt in regionale praktijken en daaruit lessen te trekken voor het rijksbeleid. De volgende onderzoeksvragen staan daarbij centraal: 1. Hoe krijgt de regionale energietransitie vorm? – Hoe vindt regionale netwerkvorming tussen partijen plaats? – Welke regionale initiatieven zijn er voor besparing, hernieuwbare bronnen en eindige bronnen (de energieladder) en in hoeverre komen ze van de grond? – Welke netwerksturing, economische en juridische sturing oefent het Rijk hierop uit? 2. Welke lessen voor het rijksbeleid zijn hieruit te trekken

The Photoactive Yellow Protein from Ectothiorhodospira halophila as Studied with a Highly Specific Polyclonal Antiserum: (Intra)cellular Localization, Regulation of Expression, and Taxonomic Distribution of Cross-Reacting Proteins

A rabbit antiserum was raised against the photoactive yellow protein (PYP) from Ectothiorhodospira halophila and purified by adsorption experiments to obtain a highly specific polyclonal antiserum. This antiserum was used to obtain the following results. (i) In E. halophila, PYP can be isolated from the fraction of soluble proteins. In the intact cell, however, PYP appeared to be associated with (intra)cytoplasmic membranes, as was concluded from analysis of immunogold-labelled thin sections of the organism. (ii) The regulation of expression of PYP was studied by using dot blot assays, Western blotting (immunoblotting), and rocket immunoelectrophoresis. Under all conditions investigated (light color, salt concentration, and growth phase), PYP was expressed constitutively in E. halophila. However, when Rhodospirillum salexigens was grown aerobically, the expression of PYP was suppressed. (iii) A large number of prokaryotic microorganisms contained a single protein, with an apparent size of approximately 15 kDa, that cross-reacted with the antiserum. Among the positively reacting organisms were both phototrophic and chemotrophic, as well as motile and nonmotile, organisms. After separation of cellular proteins into a membrane fraction and soluble proteins, it was established that organisms adapted to growth at higher salt concentrations tended to have the cross-reacting protein in the soluble fraction. In the cases of R. salegens and Chromatium salexigens, we have shown that the cross-reacting protein involved is strongly homologous to PYP from E. halophila.

Precision constraints on radiative neutrino decay with CMB spectral distortion

We investigate the radiative decay of the cosmic neutrino background and its impact on the spectrum of the cosmic microwave background (CMB) that is known to be a nearly perfect black body. We derive exact formulas for the decay of a heavier neutrino into a lighter neutrino and a photon, νj→νi+γ, and of absorption as its inverse, νi+γ→νj, by accounting for the precise form of the neutrino momentum distribution. Our calculations show that if the neutrinos are heavier than O(0.1) eV the exact formulas give results that differ by ∼50%, compared with approximate ones where neutrinos are assumed to be at rest. We also find that spectral distortion due to absorption is more important for heavy neutrino masses (by a factor of ∼10 going from a neutrino mass of 0.01-0.1 eV). By analyzing the CMB spectral data measured with COBE-FIRAS, we obtain lower limits on the neutrino lifetime of τ12 ≥ 4 × 1021 s (95% C.L.) for the smaller mass splitting and τ13∼τ23 ≥ 1019 s for the larger mass splitting. These represent up to 1 order of magnitude improvement over previous CMB constraints. With future CMB experiments such as PIXIE, these limits will improve by roughly 4 orders of magnitude. This translates to a projected upper limit on the neutrino magnetic moment (for certain neutrino masses and decay modes) of μν < 3 × 10-11 μB, where μB is the Bohr magneton. Such constraints would make future precision CMB measurements competitive with lab-based constraints on neutrino magnetic moments

Obtaining Permeability From Seismic Data - A New Breakthrough in Carbonate Reservoir Modelling

This reference is for an abstract only. A full paper was not submitted for this conference. Abstract Shell's Carbonate Team has been developing a method in which post-stackseismic can be used to estimate average interval matrix permeability incarbonates. The foundation of the technique is a new model, which describes quantitative relationships between sonic velocity, porosity and permeability. This model relates a pore shape factor from the poro-elasticity theory with permeability from lab measurements. This pore shape factor describes the 3Dpore structure and can be extracted from inverted post-stack seismic data. Additionally, this factor relates to pore connectivity and, therefore, to permeability. After the concept was tested and successfully proven on plug scale, the first implementation focused on a large carbonate field in the Middle East. This accumulation had all the ingredients to perform a full field test of the concept - good thickness for multiple seismic reflections, matrix-dominated permeability, single mineralogy (calcite), superb seismic data and enough wells with good compressional and shear sonic logs. Introducing pore structures in the characterisation of carbonate reservoirs from acoustic data helps resolve the ambiguity in porosity/permeability prediction. In the test case, we have demonstrated that: the new rock property prediction is much more accurate than properties predicted by commercial inversion packages,pore structure can be extracted from 3- Dpost-stack seismic,a permeability indicator can be estimated from inverted seismic anda permeability indicator volume proved to produce a superior history match against a permeability model constructed from extensive welldata </jats:sec