1,732 research outputs found
Quantum Chinos Game: winning strategies through quantum fluctuations
We apply several quantization schemes to simple versions of the Chinos game.
Classically, for two players with one coin each, there is a symmetric stable
strategy that allows each player to win half of the times on average. A partial
quantization of the game (semiclassical) allows us to find a winning strategy
for the second player, but it is unstable w.r.t. the classical strategy.
However, in a fully quantum version of the game we find a winning strategy for
the first player that is optimal: the symmetric classical situation is broken
at the quantum level.Comment: REVTEX4.b4 file, 3 table
K0-Sigma+ Photoproduction with SAPHIR
Preliminary results of the analysis of the reaction p(gamma,K0)Sigma+ are
presented. We show the first measurement of the differential cross section and
much improved data for the total cross section than previous data. The data are
compared with model predictions from different isobar and quark models that
give a good description of p(gamma,K+)Lambda and p(gamma,K+)Sigma0 data in the
same energy range. Results of ChPT describe the data adequately at threshold
while isobar models that include hadronic form factors reproduce the data at
intermediate energies.Comment: 4 pages, Latex2e, 4 postscript figures. Talk given at the
International Conference on Hypernuclear and Strange Particle Physics
(HYP97), Brookhaven National Laboratory, USA, October 13-18, 1997. To be
published in Nucl. Phys. A. Revised version due to changes in experimental
dat
Form factors and photoproduction amplitudes
We examine the use of phenomenological form factors in tree level amplitudes
for meson photoproduction. Two common recipes are shown to be fundamentally
incorrect. An alternate form consistent with gauge invariance and crossing
symmetry is proposed.Comment: To be published in PR
How to Educate Entrepreneurs?
Entrepreneurship education has two purposes: To improve students’ entrepreneurial skills and to provide impetus to those suited to entrepreneurship while discouraging the rest. While entrepreneurship education helps students to make a vocational decision its effects may conflict for those not suited to entrepreneurship. This study shows that vocational and the skill formation effects of entrepreneurship education can be identified empirically by drawing on the Theory of Planned Behavior. This is embedded in a structural equation model which we estimate and test using a robust 2SLS estimator. We find that the attitudinal factors posited by the Theory of Planned Behavior are positively correlated with students’ entrepreneurial intentions. While conflicting effects of vocational and skill directed course content are observed in some individuals, overall these types of content are complements. This finding contradicts previous results in the literature. We reconcile the conflicting findings and discuss implications for the design of entrepreneurship courses
Probing highly obscured, self-absorbed galaxy nuclei with vibrationally excited HCN
We present high resolution (0."4) IRAM PdBI and ALMA mm and submm
observations of the (ultra) luminous infrared galaxies ((U)LIRGs)
IRAS17208-0014, Arp220, IC860 and Zw049.057 that reveal intense line emission
from vibrationally excited (=1) J=3-2 and 4-3 HCN. The emission is
emerging from buried, compact (r<17-70 pc) nuclei that have very high implied
mid-infrared surface brightness L kpc.
These nuclei are likely powered by accreting supermassive black holes (SMBHs)
and/or hot (>200 K) extreme starbursts. Vibrational, =1, lines of HCN
are excited by intense 14 micron mid-infrared emission and are excellent probes
of the dynamics, masses, and physical conditions of (U)LIRG nuclei when H
column densities exceed cm. It is clear that these lines open
up a new interesting avenue to gain access to the most obscured AGNs and
starbursts. Vibrationally excited HCN acts as a proxy for the absorbed
mid-infrared emission from the embedded nuclei, which allows for reconstruction
of the intrinsic, hotter dust SED. In contrast, we show strong evidence that
the ground vibrational state (=0), J=3-2 and 4-3 rotational lines of HCN
and HCO fail to probe the highly enshrouded, compact nuclear regions owing
to strong self- and continuum absorption. The HCN and HCO line profiles are
double-peaked because of the absorption and show evidence of non-circular
motions - possibly in the form of in- or outflows. Detections of vibrationally
excited HCN in external galaxies are so far limited to ULIRGs and early-type
spiral LIRGs, and we discuss possible causes for this. We tentatively suggest
that the peak of vibrationally excited HCN emission is connected to a rapid
stage of nuclear growth, before the phase of strong feedback.Comment: 13 pages, 7 figures, accepted for publication in Astronomy and
Astrophysic
Debugging of Web Applications with Web-TLR
Web-TLR is a Web verification engine that is based on the well-established
Rewriting Logic--Maude/LTLR tandem for Web system specification and
model-checking. In Web-TLR, Web applications are expressed as rewrite theories
that can be formally verified by using the Maude built-in LTLR model-checker.
Whenever a property is refuted, a counterexample trace is delivered that
reveals an undesired, erroneous navigation sequence. Unfortunately, the
analysis (or even the simple inspection) of such counterexamples may be
unfeasible because of the size and complexity of the traces under examination.
In this paper, we endow Web-TLR with a new Web debugging facility that supports
the efficient manipulation of counterexample traces. This facility is based on
a backward trace-slicing technique for rewriting logic theories that allows the
pieces of information that we are interested to be traced back through inverse
rewrite sequences. The slicing process drastically simplifies the computation
trace by dropping useless data that do not influence the final result. By using
this facility, the Web engineer can focus on the relevant fragments of the
failing application, which greatly reduces the manual debugging effort and also
decreases the number of iterative verifications.Comment: In Proceedings WWV 2011, arXiv:1108.208
A rare cause of obstructive jaundice: diagnosis by EUS and single-operator per-oral cholangioscopy
Access to Preprimary Education and Progression in Primary School: Evidence from Rural Guatemala
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