649 research outputs found
Existence as Economy and as Charity
Antonio Caso, “La existencia como economĂa y como caridad” (1916). Translated with Jose G. Rodriguez Jr. as “Existence as Economy and as Charity,” in 20th Century Mexican Philosophy: Essential Readings, eds. Carlos Alberto Sánchez and Robert Eli Sanchez, Jr. (New York: Oxford University Press, 2017)
Existence as Economy and as Charity An Essay on the essence of Christianity (1916) by: Antonio Caso
Antonio Caso rejects the effort of biologists to reduce life to the organic world, a sphere of existence that is defined by economy and egoism, best summarized in the formula: Life = Minimum Effort x Maximum Gain. The problem is that this cannot explain what he calls “disinterested activity,” such as play, art, and self-sacrifice. His primary example of disinterested or selfless activity is the life of Jesus, which Caso also believes is the height of human dignity. In other words, Caso not only argues that there is more than one order of life or existence; he also argues that selfless activity is ultimately what distinguishes human life, whose best expression is found in the essence of Christianity: to give oneself to others “without fear of exhaustion.” To be human is to be willing to sacrifice oneself, best expressed in the following formula: Sacrifice = Maximum Effort x Minimum Gain
Past electron-positron g-2 experiments yielded sharpest bound on CPT violation for point particles
In our past experiments on a single electron and positron we measured the
cyclotron and spin-cyclotron difference frequencies omega_c and omega_a and the
ratios a = omega_a/ omega_c at omega_c = 141 Ghz for e^- and e^+ and later,
only for e^-, also at 164 Ghz. Here, we do extract from these data, as had not
done before, a new and very different figure of merit for violation of CPT
symmetry, one similar to the widely recognized impressive limit |m_Kaon -
m_Antikaon|/m_Kaon < 10^-18 for the K-mesons composed of two quarks. That
expression may be seen as comparing experimental relativistic masses of
particle states before and after the C, P, T operations had transformed
particle into antiparticle. Such a similar figure of merit for a non-composite
and quite different lepton, found by us from our Delta a = a^- - a^+ data, was
even smaller, h_bar |omega_a^- - omega_a^+|/2m_0 c^2 = |Delta a| h_bar
omega_c/2m_0 c^2) < 3(12) 10^-22.Comment: Improved content, Editorially approved for publication in PRL, LATEX
file, 5 pages, no figures, 16
Signature for heavy Majorana neutrinos in hadronic collisions
The production and decay of new possible heavy Majorana neutrinos are
analyzed in hadronic collisions. New bounds on the mixing of these particles
with standard neutrinos are estimated according to a fundamental representation
suggested by grand unified models. A clear signature for these Majorana
neutrinos is given by same-sign dileptons plus a charged weak vector boson in
the final state. We discuss the experimental possibilities for the future Large
Hadron Collider (LHC) at CERN.Comment: Latex2e(epsfig), 12 pages, 8 figures, to appear Physical Review
Tritium Beta Decay, Neutrino Mass Matrices and Interactions Beyond the Standard Model
The interference of charge-changing interactions, weaker than the V-A
Standard Model (SM) interaction and having a different Lorentz structure, with
that SM interaction, can, in principle, produce effects near the end point of
the Tritium beta decay spectrum which are of a different character from those
produced by the purely kinematic effect of neutrino mass expected in the
simplest extension of the SM. We show that the existence of more than one mass
eigenstate can lead to interference effects at the end point that are stronger
than those occurring over the entire spectrum. We discuss these effects both
for the special case of Dirac neutrinos and the more general case of Majorana
neutrinos and show that, for the present precision of the experiments, one
formula should suffice to express the interference effects in all cases.
Implications for "sterile" neutrinos are noted.Comment: 32 pages, LaTeX, 6 figures, PostScript; full discussion and changes
in notation from Phys. Lett. B440 (1998) 89, nucl-th/9807057; submitted to
Phys. Rev.
Mathematical modelling of polyamine metabolism in bloodstream-form trypanosoma brucei: An application to drug target identification
© 2013 Gu et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedThis article has been made available through the Brunel Open Access Publishing Fund.We present the first computational kinetic model of polyamine metabolism in bloodstream-form Trypanosoma brucei, the causative agent of human African trypanosomiasis. We systematically extracted the polyamine pathway from the complete metabolic network while still maintaining the predictive capability of the pathway. The kinetic model is constructed on the basis of information gleaned from the experimental biology literature and defined as a set of ordinary differential equations. We applied Michaelis-Menten kinetics featuring regulatory factors to describe enzymatic activities that are well defined. Uncharacterised enzyme kinetics were approximated and justified with available physiological properties of the system. Optimisation-based dynamic simulations were performed to train the model with experimental data and inconsistent predictions prompted an iterative procedure of model refinement. Good agreement between simulation results and measured data reported in various experimental conditions shows that the model has good applicability in spite of there being gaps in the required data. With this kinetic model, the relative importance of the individual pathway enzymes was assessed. We observed that, at low-to-moderate levels of inhibition, enzymes catalysing reactions of de novo AdoMet (MAT) and ornithine production (OrnPt) have more efficient inhibitory effect on total trypanothione content in comparison to other enzymes in the pathway. In our model, prozyme and TSHSyn (the production catalyst of total trypanothione) were also found to exhibit potent control on total trypanothione content but only when they were strongly inhibited. Different chemotherapeutic strategies against T. brucei were investigated using this model and interruption of polyamine synthesis via joint inhibition of MAT or OrnPt together with other polyamine enzymes was identified as an optimal therapeutic strategy.The work was carried out under a PhD programme partly funded by Prof. Ray Welland, School of Computing Science, University of Glasgo
Experimental Bounds on Masses and Fluxes of Nontopological Solitons
We have re-analyzed the results of various experiments which were not
originally interested as searches for the Q-ball or the Fermi-ball. Based on
these analyses, in addition to the available data on Q-balls, we obtained
rather stringent bounds on flux, mass and typical energy scale of Q-balls as
well as Fermi-balls. In case these nontopological solitons are the main
component of the dark matter of the Galaxy, we found that only such solitons
with very large quantum numbers are allowed. We also estimate how sensitive
future experiments will be in the search for Q-balls and Fermi-balls.Comment: 19 pages, 7 eps figures, RevTeX, psfig.st
Signals for CPT and Lorentz Violation in Neutral-Meson Oscillations
Experimental signals for indirect CPT violation in the neutral-meson systems
are studied in the context of a general CPT- and Lorentz-violating
standard-model extension. In this explicit theory, some CPT observables depend
on the meson momentum and exhibit diurnal variations. The consequences for CPT
tests vary significantly with the specific experimental scenario. The wide
range of possible effects is illustrated for two types of CPT experiment
presently underway, one involving boosted uncorrelated kaons and the other
involving unboosted correlated kaon pairs.Comment: Accepted in Physical Review D, scheduled for December 1999 issu
Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis
Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al
Can three-flavor oscillations solve the solar neutrino problem?
The most promising solution to the solar neutrino problem are neutrino
oscillations, which usually are analyzed within the reduced 2-flavor scheme,
because the solutions found therein reasonably well reproduce the recent data
of Super-Kamiokande about the recoil-electron energy spectrum, zenith-angle and
seasonal variations, and the event rate data of all the neutrino detectors. In
this work, however, a survey of the complete parameter space of 3-flavor
oscillations is performed. Basically eight new additional solutions could be
identified, where the best one with \Delta m(12)^2=2.7x10^(-10) eV^2, \Delta
m(13)^2=1.0x10^(-5) eV^2, \Theta(12)=23, and \Theta(13)=1.3 (denoted SVO) is
slightly more probable than any 2-flavor solution. However, including the
results of the atmospheric neutrino problem excludes all 3-flavour solutions
apart from the SLMA-solution (\Delta m(12)^2=7.9x10^(-6) eV^2, \Delta
m(13)^2=2.5x10^(-4) eV^2, \Theta(12)=1.4, and \Theta(13)=20). Besides, the
ability of SNO and Borexino to discriminate the various 2- and 3-flavor
solutions is investigated. Only with very good statistics in these experiments
the correct solution to the solar neutrino problem can be identified
unambiguously.Comment: 22 pages, 19 figures, REVTeX, submitted to Phys.Rev.D, article with
better resolved figures available under
http://www.mpa-garching.mpg.de/~schlattl/public.htm
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