Effect of ambient temperature variations on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella

[EN] Two outdoor photobioreactors were operated to evaluate the effect of variable ambient temperature on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella. Four experiments were carried out in different seasons, maintaining the temperature-controlled PBR at around 25¿°C (by either heating or cooling), while the temperature in the non-temperature-controlled PBR was allowed to vary with the ambient conditions. Temperatures in the range of 15¿30¿°C had no significant effect on the microalgae cultivation performance. However, when the temperature rose to 30¿35¿°C microalgae viability was significantly reduced. Sudden temperature rises triggered AOB growth in the indigenous microalgae culture, which worsened microalgae performance, especially when AOB activity made the system ammonium-limited. Microalgae activity could be recovered after a short temperature peak over 30¿°C once the temperature dropped, but stopped when the temperature was maintained around 28¿30¿°C for several days.This research work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO, Projects CTM2014-54980-C2-1-R and CTM2014-54980-C2-2-R) jointly with the European Regional Development Fund (ERDF), both of which are gratefully acknowledged. It also received support from the Spanish Ministry of Education, Culture and Sport via a pre-doctoral FPU fellowship to authors J. González-Camejo (FPU14/05082) and S. Aparicio (FPU/15/02595).Gonzalez-Camejo, J.; Aparicio Antón, SE.; Ruano, M.; Borrás, L.; Barat, R.; Ferrer, J. (2019). Effect of ambient temperature variations on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella. Bioresource Technology. 290:1-10. https://doi.org/10.1016/j.biortech.2019.121788S11029

A frequentist analysis of solar neutrino data

We calculate with Monte Carlo the goodness of fit and the confidence level of the standard allowed regions for the neutrino oscillation parameters obtained from the fit of solar neutrino data. We show that the values of the goodness of fit and of the confidence level of the allowed regions are significantly smaller than the standard ones. Using Neyman's method, we also calculate exact allowed regions with correct frequentist coverage. We show that the standard allowed region around the global minimum of the least-squares function is a reasonable approximation of the exact one, whereas the size of the other regions is dramatically underestimated in the standard method.Comment: 19 page

Strong 3D correlations in vortex system of Bi2212:Pb

The experimental study of magnetic flux penetration under crossed magnetic fields in Bi2212:Pb single crystal performed by magnetooptic technique (MO) reveals remarkable field penetration pattern alteration (flux configuration change) and superconducting current anisotropy enhancement by the in-plane field. The anisotropy increases with the temperature rise up to $T_m = 54 \pm 2 K$. At $T = T_m$ an abrupt change in the flux behavior is found; the correlation between the in-plane magnetic field and the out-of-plane magnetic flux penetration disappears. No correlation is observed for $T > T_m$. The transition temperature $T_m$ does not depend on the magnetic field strength. The observed flux penetration anisotropy is considered as an evidence of a strong 3D - correlation between pancake vortices in different CuO planes at $T < T_m$. This enables understanding of a remarkable pinning observed in Bi2212:Pb at low temperatures.Comment: 8 pages, 9 figure

Mammal and tree diversity accumulate different types of soil organic matter in the northern Amazon

Diversity of plants and animals influence soil carbon through their contributions to soil organic matter (SOM). However, we do not know whether mammal and tree communities affect SOM composition in the same manner. This question is relevant because not all forms of carbon are equally resistant to mineralization by microbes and thus, relevant to carbon storage. We analyzed the elemental and molecular composition of 401 soil samples, with relation to the species richness of 83 mammal and tree communities at a landscape scale across 4.8 million hectares in the northern Amazon. We found opposite effects of mammal and tree richness over SOM composition. Mammal diversity is related to SOM rich in nitrogen, sulfur and iron whereas tree diversity is related to SOM rich in aliphatic and carbonyl compounds. These results help us to better understand the role of biodiversity in the carbon cycle and its implications for climate change mitigation.Xunta de Galicia | ED481D 2019/024Xunta de Galicia | ED431C2021/32European Commission | Ref. H2020, n. 947921National Science Foundation (NSF) | BE/CNH 05 0809

Three-Neutrino Mixing after the First Results from K2K and KamLAND

We analyze the impact of the data on long baseline \nu_\mu disappearance from the K2K experiment and reactor \bar\nu_e disappearance from the KamLAND experiment on the determination of the leptonic three-generation mixing parameters. Performing an up-to-date global analysis of solar, atmospheric, reactor and long baseline neutrino data in the context of three-neutrino oscillations, we determine the presently allowed ranges of masses and mixing and we consistently derive the allowed magnitude of the elements of the leptonic mixing matrix. We also quantify the maximum allowed contribution of \Delta m^2_{21} oscillations to CP-odd and CP-even observables at future long baseline experiments.Comment: Some typos correcte

Robust signatures of solar neutrino oscillation solutions

With the goal of identifying signatures that select specific neutrino oscillation parameters, we test the robustness of global oscillation solutions that fit all the available solar and reactor experimental data. We use three global analysis strategies previously applied by different authors and also determine the sensitivity of the oscillation solutions to the critical nuclear fusion cross section, S_{17}(0), for the production of 8B. The favored solutions are LMA, LOW, and VAC in order of g.o.f. The neutral current to charged current ratio for SNO is predicted to be 3.5 +- 0.6 (1 sigma), which is separated from the no-oscillation value of 1.0 by much more than the expected experimental error. The predicted range of the day-night difference in charged current rates is (8.2 +- 5.2)% and is strongly correlated with the day-night effect for neutrino-electron scattering. A measurement by SNO of either a NC to CC ratio > 3.3 or a day-night difference > 10%, would favor a small region of the currently allowed LMA neutrino parameter space. The global oscillation solutions predict a 7Be neutrino-electron scattering rate in BOREXINO and KamLAND in the range 0.66 +- 0.04 of the BP00 standard solar model rate, a prediction which can be used to test both the solar model and the neutrino oscillation theory. Only the LOW solution predicts a large day-night effect(< 42%) in BOREXINO and KamLAND. For the KamLAND reactor experiment, the LMA solution predicts 0.44 of the standard model rate; we evaluate 1 sigma and 3 sigma uncertainties and the first and second moments of the energy spectrum.Comment: Included predictions for KamLAND reactor experiment and updated to include 1496 days of Super-Kamiokande observation

Transport Properties through Double Barrier Structure in Graphene

The mode-dependent transmission of relativistic ballistic massless Dirac fermion through a graphene based double barrier structure is being investigated for various barrier parameters. We compare our results with already published work and point out the relevance of these findings to a systematic study of the transport properties in double barrier structures. An interesting situation arises when we set the potential in the leads to zero, then our 2D problem reduces effectively to a 1D massive Dirac equation with an effective mass proportional to the quantized wave number along the transverse direction. Furthermore we have shown that the minimal conductivity and maximal Fano factor remain insensitive to the ratio between the two potentials V_2/V_1=\alpha.Comment: 18 pages, 12 figures, clarifications and reference added, misprints corrected. Version to appear in JLT

Model Independent Information On Solar Neutrino Oscillations

We present the results of a Bayesian analysis of solar neutrino data in terms of nu_e->nu_{mu,tau} oscillations, independent from the Standard Solar Model predictions for the solar neutrino fluxes. We show that such a model independent analysis allows to constraint the values of the neutrino mixing parameters in limited regions around the usual SMA, LMA, LOW and VO regions. Furthermore, there is a strong indication in favor of large neutrino mixing and large values of Delta m^2 (LMA region). We calculate also the allowed ranges of the neutrino fluxes and we show that they are in good agreement with the Standard Solar Model prediction. In particular, the ratio of the 8B flux with its Standard Solar Model prediction is constrained in the interval [0.45,1.42] with 99.73% probability. Finally, we show that the hypothesis of no neutrino oscillations is strongly disfavored in a model independent way with respect to the hypothesis of neutrino oscillations.Comment: 40 pages, 20 figures. Added references and improved figure

Status of four-neutrino mass schemes: a global and unified approach to current neutrino oscillation data

We present a unified global analysis of neutrino oscillation data within the framework of the four-neutrino mass schemes (3+1) and (2+2). We include all data from solar and atmospheric neutrino experiments, as well as information from short-baseline experiments including LSND. If we combine only solar and atmospheric neutrino data, (3+1) schemes are clearly preferred, whereas short-baseline data in combination with atmospheric data prefers (2+2) models. When combining all data in a global analysis the (3+1) mass scheme gives a slightly better fit than the (2+2) case, though all four-neutrino schemes are presently acceptable. The LSND result disfavors the three-active neutrino scenario with only $\Delta m^2_{sol}$ and $\Delta m^2_{atm}$ at 99.9% CL with respect to the four-neutrino best fit model. We perform a detailed analysis of the goodness of fit to identify which sub-set of the data is in disagreement with the best fit solution in a given mass scheme.Comment: 32 pages, 8 Figures included, REVTeX4.Improved discussion in sec. XI, references added, version accepted by Phys. Rev.

Three Generation Neutrino Oscillation Parameters after SNO

We examine the solar neutrino problem in the context of the realistic three neutrino mixing scenario including the SNO charged current (CC) rate. The two independent mass squared differences $\Delta m^2_{21}$ and $\Delta m^2_{31} \approx \Delta m^2_{32}$ are taken to be in the solar and atmospheric ranges respectively. We incorporate the constraints on $\Delta$m$^2_{31}$ as obtained by the SuperKamiokande atmospheric neutrino data and determine the allowed values of $\Delta m^2_{21}$, $\theta_{12}$ and $\theta_{13}$ from a combined analysis of solar and CHOOZ data. Our aim is to probe the changes in the values of the mass and mixing parameters with the inclusion of the SNO data as well as the changes in the two-generation parameter region obtained from the solar neutrino analysis with the inclusion of the third generation. We find that the inclusion of the SNO CC rate in the combined solar + CHOOZ analysis puts a more restrictive bound on $\theta_{13}$. Since the allowed values of $\theta_{13}$ are constrained to very small values by the CHOOZ experiment there is no qualitative change over the two generation allowed regions in the $\Delta m^2_{21} - \tan^2 \theta_{12}$ plane. The best-fit comes in the LMA region and no allowed area is obtained in the SMA region at 3$\sigma$ level from combined solar and CHOOZ analysis.Comment: One reference added. Version to apprear in PR