A new spin on neutrino quantum kinetics Cirigliano, Vincenzo; Fuller, George M.; Vlasenko, Alexey
Physics letters. B,
07/2015, Letnik:
747, Številka:
C
Journal Article
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Recent studies have demonstrated that in anisotropic environments a coherent spin-flip term arises in the Quantum Kinetic Equations (QKEs) which govern the evolution of neutrino flavor and spin in ...hot and dense media. This term can mediate neutrino–antineutrino transformation for Majorana neutrinos and active-sterile transformation for Dirac neutrinos. We discuss the physical origin of the coherent spin-flip term and provide explicit expressions for the QKEs in a two-flavor model with spherical geometry. In this context, we demonstrate that coherent neutrino spin transformation depends on the absolute neutrino mass and Majorana phases.
Systemic inflammatory response variability displays differing degrees of organ damage and differing outcomes of sepsis. C1-esterase inhibitor, an endogenous acute-phase protein, regulates various ...inflammatory and anti-inflammatory pathways, including the kallikrein-kinin system and leukocyte activity. This study assesses the influence of high-dose C1-esterase inhibitor administration on systemic inflammatory response and survival in patients with sepsis.
Open-label randomized controlled study.
Surgical and medical intensive care units of nine university and city hospitals.
: Sixty-one patients with sepsis.
Patients were randomized to receive either 12,000 U of C1-esterase inhibitor infusions in addition to conventional treatment or conventional treatment only (n = 41 C1-esterase inhibitor, 20 controls). Blood samples for measurement of C1-esterase inhibitor, complement components C3 and C4, and C-reactive protein concentrations were drawn on days 1, 3, 5, 7, 10, and 28.
Quartile analysis of C1-esterase inhibitor activity in sepsis subjects revealed that the lowest quartile subgroup had similar activity levels (0.7-1.2 U/L), when compared to healthy volunteers (p > .05). These normal-level C1-esterase inhibitor sepsis patients nevertheless displayed increased C-reactive protein (p = .04) production and higher likelihoods of a more severe sepsis (p = .001). Overall, infusion of C1-esterase inhibitor increased C1-esterase inhibitor (p < .005 vs. control on days 2, 3, and 5) functional activity, resulted in higher C3 levels (p < .05 vs. control on days 2 and 3), followed by decreased C-reactive protein (p < .05 vs. control on days 3 and 10). Simultaneously, C1-esterase inhibitor infusion in sepsis patients was associated with reduced all-cause mortality (12% vs. 45% in control, p = .008) as well as sepsis-related mortality (8% vs. 45% in control, p = .001) assessed over 28 days. The highest absolute reduction risk of 70% was achieved in sepsis patients with Simplified Acute Physiology Score II scores >27.
In the present study, patients in the lowest quartile of C1-esterase inhibitor activity in combination with high C-reactive protein demonstrated a higher risk of developing severe sepsis. In general, high-dose C1-esterase inhibitor infusion down-regulated the systemic inflammatory response and was associated with improved survival rates in sepsis patients, which could have important treatment and survival implications for individuals with C1-esterase inhibitor functional deficiency.
We introduce a new computational capability that moves toward a self-consistent calculation of neutrino transport and nuclear reactions for big bang nucleosynthesis (BBN). Such a self-consistent ...approach is needed to be able to extract detailed information about nuclear reactions and physics beyond the standard model from precision cosmological observations of primordial nuclides and the cosmic microwave background radiation. We calculate the evolution of the early universe through the epochs of weak decoupling, weak freeze-out and big bang nucleosynthesis (BBN) by simultaneously coupling a full strong, electromagnetic, and weak nuclear reaction network with a multi-energy group Boltzmann neutrino energy transport scheme. The modular structure of our approach allows the dissection of the relative contributions of each process responsible for evolving the dynamics of the early universe. Such an approach allows a detailed account of the evolution of the active neutrino energy distribution functions alongside and self-consistently with the nuclear reactions and entropy/heat generation and 'ow between the neutrino and photon/electron/positron/baryon plasma components. Our calculations reveal nonlinear feedback in the time evolution of neutrino distribution functions and plasma thermodynamic conditions. We discuss the time development of neutrino spectral distortions and concomitant entropy production and extraction from the plasma. These e↑ects result in changes in the computed values of the BBN deuterium and helium-4 yields that are on the order of a half-percent relative to a baseline standard BBN calculation with no neutrino transport. This is an order of magnitude larger e↑ect than in previous estimates. For particular implementations of quantum corrections in plasma thermodynamics, our calculations show a 0.4% increase in deuterium and a 0.6% decrease in 4He over our baseline. The magnitude of these changes are on the order of uncertainties in the nuclear physics for the case of deuterium and are potentially signi↓cant for the error budget of helium in upcoming cosmological observations.
Rad55 protein is one of two Rad51 paralogs in the budding yeast Saccharomyces cerevisiae and forms a stable heterodimer with Rad57, the other Rad51 paralog. The Rad55-Rad57 heterodimer functions in ...homologous recombination during the assembly of the Rad51-ssDNA filament, which is central for homology search and DNA strand exchange. Previously, we identified Rad55 protein as a terminal target of the DNA damage checkpoints, which coordinate the cellular response to genotoxic stress. Rad55 protein phosphorylation is signaled by a significant electrophoretic shift and occurs in response to a wide range of genotoxic stress. Here, we map the phosphorylation site leading to the electrophoretic shift and show that Rad55 protein is a bona fide direct in vivo substrate of the central DNA damage checkpoint kinase Mec1, the budding yeast equivalent of human ATM/ATR. We provide protocols to monitor the Rad55 phosphorylation status in vivo and assay Rad55-Rad57 phosphorylation in vitro using purified substrate with the Mec1 and Rad53 checkpoint kinases.
The subject of this dissertation is the evolution of neutrino distributions in hot, dense astrophysical environments, such as the early Universe, core collapse supernovae or compact object mergers. ...This is an important problem in astrophysics because the dynamics and the composition of these systems can be strongly influenced by neutrinos, leading to potential modification of nucleosynthesis and of astrophysical observables. In these environments, neutrinos can undergo both coherent forward scattering and direction-changing or inelastic collisions. The transport equations for flavored neutrinos, or quantum kinetic equations (QKEs), are derived from first principles, beginning with quantum field theory and Standard Model neutrino interactions. The QKEs can reduce to the standard Schrödinger-like equations for neutrino flavor evolution in the limit of low matter density, and to a Boltzmann-like equation describing neutrino scat tering at high density. In addition, in high-density, anisotropic environments we find a novel process that can mediate coherent exchange of particle number and flavor information between neutrino and antineutrino states (spin coherence). We discuss the prospects for modification of the standard picture of neutrino flavor evolution in supernovae and other astrophysical environments by non-forward scattering and spin coherence.
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