New Insight into Antiproton Production and Reabsorption Using Proton-Nucleus Collisions at the AGS

Antiproton ($\bar{p}$) yields are presented for proton-nucleus collisions, with targets Be, Cu, and Au, at beam momenta of 12.3 and 17.5 GeV/c. In addition to target size and beam momentum, the number of projectile collisions $\nu$, as derived from the number of ``grey'' tracks (slow protons and deuterons), is used to disentangle the $\bar{p}$ reabsorption from the production. By quantifying the amount of reabsorption of the $\bar{p}$ within the nucleus as a function of $\nu$, the annihilation within the nucleus is estimated and compared to the free annihilation cross section. Preliminary results on antilambda ($\bar{\Lambda}$) production as a function of $\nu$ are also presented for comparison.Comment: 4 pages including 4 figure

Do pedagogues need realistic metaphysics?

Artykuł stara się odpowiedzieć na pytanie zawarte w tytule: po co pedagogom metafizyka realistyczna? W pierwszej części autor wyjaśnia różnicę między potocznym a filozoficznym znaczeniem terminu "metafizyka". Opisuje rozumienie metafizyki realistycznej według Lubelskiej Szkoły Filozoficznej. Metafizyczne rozumienie rzeczywistości opisywane w tej szkole opiera się na teorii analogii bytowej, której poświęcona jest główna część artykułu. Dzięki analogii w każdym bycie, a więc i w bycie ludzkim, odkrywane są transcendentalne właściwości inteligibilności i amabilności. To one stanowią najgłębszy fundament poznawalności i akceptacji bytu ludzkiego, na którym opiera się pedagogika.The article attempts to answer the question contained in the title: "Do pedagogues need realistic metaphysics?". In the first part of the text the author explains the difference between the colloquial and philosophical meanings of the term "metaphysics". The author describes realistic metaphysics in accordance with how it is understood by the Philosophical School of Lublin. The metaphysical understanding of reality that is described by this school is based on the theory of the analogy of being. The main part of the article is dedicated to this theory. The transcendental features of the intelligibility and desirability of being are discovered, thanks to the existence of the analogy in every being, including human beings. These features are the deepest foundation of the intelligibility and acceptance of the human being, on which pedagogy is based

VLBA Determination of the Distance to Nearby Star-forming Regions. IV. A Preliminary Distance to the Proto-Herbig AeBe Star EC 95 in the Serpens Core

Using the Very Long Base Array, we observed the young stellar object EC 95 in the Serpens cloud core at eight epochs from 2007 December to 2009 December. Two sources are detected in our field and are shown to form a tight binary system. The primary (EC 95a) is a 4-5 M_⊙ proto-Herbig AeBe object (arguably the youngest such object known), whereas the secondary (EC 95b) is most likely a low-mass T Tauri star. Interestingly, both sources are non-thermal emitters. While T Tauri stars are expected to power a corona because they are convective while they go down the Hayashi track, intermediate-mass stars approach the main sequence on radiative tracks. Thus, they are not expected to have strong superficial magnetic fields, and should not be magnetically active. We review several mechanisms that could produce the non-thermal emission of EC 95a and argue that the observed properties of EC 95a might be most readily interpreted if it possessed a corona powered by a rotation-driven convective layer. Using our observations, we show that the trigonometric parallax of EC 95 is π = 2.41 ± 0.02 mas, corresponding to a distance of 414.9^(+4.4)_ (–4.3) pc. We argue that this implies a distance to the Serpens core of 415 ± 5 pc and a mean distance to the Serpens cloud of 415 ± 25 pc. This value is significantly larger than previous estimates (d ~ 260 pc) based on measurements of the extinction suffered by stars in the direction of Serpens. A possible explanation for this discrepancy is that these previous observations picked out foreground dust clouds associated with the Aquila Rift system rather than Serpens itself