This paper discusses Herbert A. Simon's conception of rationality in two of its principal general definitions: bounded rationality and procedural rationality. It argues that the latter is the one that better synthesizes the author's view about rational behavior and that the former fills mainly a critical function. They are complementarily used by Simon in this sense. In spite of that, it is argued that it is the low degree of specificity of the concept of bounded rationality one of the reasons for its relatively greater success
Context. Observations of gamma-ray bursts (GRBs) have shown an hybridization between the two classes of long and short bursts. In the context of the fireshell model, the GRB light curves are formed by two different components: the proper GRB (P-GRB) and the extended afterglow. Their relative intensity is linked to the fireshell baryon loading B. The GRBs with P-GRB predominance are the short ones, the remainders are long. A new family of disguised short bursts has been identified: long bursts with a protracted low instantaneous luminosity due to a low density CircumBurst Medium (CBM). In the 15-150 keV energy band GRB 071227 exhibits a short duration (about 1.8 s) spike-like emission followed by a very soft extended tail up to one hundred seconds after the trigger. It is a faint (E iso = 5.8 × 10 50 ) nearby GRB (z = 0.383) that does not have an associated type Ib/c bright supernova (SN). For these reasons, GRB 071227 has been classified as a short burst not fulfilling the Amati relation holding for long burst. Aims. We check the classification of GRB 071227 provided by the fireshell model. In particular, we test whether this burst is another example of a disguised short burst, after GRB 970228 and GRB 060614, and, for this reason, whether it fulfills the Amati relation. Methods. We simulate GRB 071227 light curves in the Swift BAT 15-50 keV bandpass and in the XRT (0.3-10 keV) energy band within the fireshell model. Results. We perform simulations of the tail in the 15-50 keV bandpass, as well as of the first part of the X-ray afterglow. This infers that: E e ± tot = 5.04 × 10 51 erg, B = 2.0 × 10 −4 , E P−GRB /E aft ∼ 0.25, and n cbm = 3.33 particles cm −3 . These values are consistent with those of "long duration" GRBs. We interpret the observed energy of the first hard emission by identifying it with the P-GRB emission. The remaining long soft tail indeed fulfills the Amati relation. Conclusions. Previously classified as a short burst, GRB 071227 on the basis of our analysis performed in the context of the fireshell scenario represents another example of a disguised short burst, after GRB 970228 and GRB 060614. Further confirmation of this result is that the soft tail of GRB 071227 fulfills the Amati relation.
Context. GRB 050509b, detected by the Swift satellite, is the first case where an X-ray afterglow has been observed associated with a short gamma-ray burst (GRB). Within the fireshell model, the canonical GRB light curve presents two different components: the proper-GRB (P-GRB) and the extended afterglow. Their relative intensity is a function of the fireshell baryon loading parameter B and of the CircumBurst Medium (CBM) density (n CBM ). In particular, the traditionally called short GRBs can be either "genuine" short GRBs (with B 10 −5 , where the P-GRB is energetically predominant) or "disguised" short GRBs (with B 3.0 × 10 −4 and n CBM 1, where the extended afterglow is energetically predominant). Aims. We verify whether GRB 050509b can be classified as a "genuine" short or a "disguised" short GRB, in the fireshell model. Methods. We investigate two alternative scenarios. In the first, we start from the assumption that this GRB is a "genuine" short burst.In the second attempt, we assume that this GRB is a "disguised" burst. Results. If GRB 050509b were a genuine short GRB, there should initially be very hard emission, which is ruled out by the observations. The analysis that assumes that this is a disguised short GRB is compatible with the observations. The theoretical model predicts a value of the extended afterglow energy peak that is consistent with the Amati relation. Conclusions. GRB 050509b cannot be classified as a "genuine" short GRB. The observational data are consistent with a "disguised" short GRB classification, i.e., a long burst with a weak extended afterglow "deflated" by the low density of the CBM. We expect that all short GRBs with measured redshifts are disguised short GRBs because of a selection effect: if there is enough energy in the afterglow to measure the redshift, then the proper GRB must be less energetic than the afterglow. The Amati relation is found to be fulfilled only by the extended afterglow excluding the P-GRB.
The observation of GRB 080319B, with an isotropic energy E iso = 1.32 × 10 54 erg, and GRB 050904, with E iso = 1.04 × 10 54 erg, offers the possibility of studying the spectral properties of the prompt radiation of two of the most energetic gamma-ray bursts (GRBs). This allows us to probe the validity of the fireshell model for GRBs beyond 10 54 erg, well outside the energy range where it has been successfully tested up to now (10 49 -10 53 erg). We find that in the low-energy region, the prompt emission spectra observed by Swift Burst Alert Telescope (BAT) reveals more power than theoretically predicted. The opportunities offered by these observations to improve the fireshell model are outlined in this paper. One of the distinguishing features of the fireshell model is that it relates the observed GRB spectra to the spectrum in the comoving frame of the fireshell. Originally, a fully radiative condition and a comoving thermal spectrum were adopted. An additional power law in the comoving thermal spectrum is required due to the discrepancy of the theoretical and observed light curves and spectra in the fireshell model for GRBs 080319B and 050904. A new phenomenological parameter α is correspondingly introduced in the model. We perform numerical simulations of the prompt emission in the Swift BAT bandpass by assuming different values of α within the fireshell model. We compare them with the GRB 080319B and GRB 050904 observed time-resolved spectra, as well as with their time-integrated spectra and light curves. Although GRB 080319B and GRB 050904 are at very different redshifts (z = 0.937 and z = 6.29, respectively), a value of α = −1.8 for both of them leads to a good agreement between the numerical simulations and the observed BAT light curves, time-resolved and timeintegrated spectra. Such a modified spectrum is also consistent with the observations of previously analyzed less energetic GRBs and reasons for this additional agreement are given. Perspectives for future low-energy missions are outlined.
BackgroundApis mellifera venom, which has already been recommended as an alternative anti-inflammatory treatment, may be also considered an important source of candidate molecules for biotechnological and biomedical uses, such as the treatment of parasitic diseases.MethodsAfricanized honeybee venom from Apis mellifera was fractionated by RP-C18-HPLC and the obtained melittin was incubated with promastigotes and intracellular amastigotes of Leishmania (L.) infantum. Cytotoxicity to mice peritoneal macrophages was evaluated through mitochondrial oxidative activity. The production of anti- and pro-inflammatory cytokines, NO and H2O2 by macrophages was determined.ResultsPromastigotes and intracellular amastigotes were susceptible to melittin (IC50 28.3 μg.mL−1 and 1.4 μg.mL−1, respectively), but also showed mammalian cell cytotoxicity with an IC50 value of 5.7 μg.mL−1. Uninfected macrophages treated with melittin increased the production of IL-10, TNF-α, NO and H2O2. Infected melittin-treated macrophages increased IL-12 production, but decreased the levels of IL-10, TNF-α, NO and H2O2.ConclusionsThe results showed that melittin acts in vitro against promastigotes and intracellular amastigotes of Leishmania (L.) infantum. Furthermore, they can act indirectly on intracellular amastigotes through a macrophage immunomodulatory effect.
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