214 research outputs found
Estimated Benefits of Increased Visitation to Vancouver, BC, via Rail and Float Plane
There currently are proposals from two separate carriers to provide increased passenger service in the corridor between Seattle, WA, and Vancouver, BC. Amtrak proposes to add a second daily train along that route, and Kenmore Air proposes to initiate float plane service from Lake Union (Seattle) to Vancouver Harbour. This note provides an estimate of the economic benefit to Vancouver of the associated increase in visitation. The note considers only the benefits derived from tourism
Can this wait? Civil conflict negotiation and the content of ethnic identity
Current approaches to the negotiated resolution of ethnic civil conflict either ignore or negate the impact of the content of ethnic identities on the negotiation process, or alternatively assume without sufficient evidence that violent conflict is caused by conflicting ethnic narratives. Based upon a comparison of the Israeli-Palestinian and Northern Ireland conflicts and negotiation processes, this thesis suggests a third perspective. While the evidence does not support the contention that conflicting ethnic narratives cause violent civil conflict to occur, identity-based issues can present tremendous barriers to negotiated agreement. The postponement of the central identity-based issue was critical to the success of the Northern Ireland peace process, and the inclusion of such issues for permanent resolution was equally critical to the failure of the Israeli-Palestinian negotiations. These findings suggest that the postponement of permanently resolving such issues until after the cause of conflict is addressed may offer a more promising strategy for ending violent civil conflict than alternatives hitherto explored
Thermal equilibrium of a macroscopic quantum system in a pure state
We consider the notion of thermal equilibrium for an individual closed
macroscopic quantum system in a pure state, i.e., described by a wave function.
The macroscopic properties in thermal equilibrium of such a system, determined
by its wave function, must be the same as those obtained from thermodynamics,
e.g., spatial uniformity of temperature and chemical potential. When this is
true we say that the system is in macroscopic thermal equilibrium (MATE). Such
a system may however not be in microscopic thermal equilibrium (MITE). The
latter requires that the reduced density matrices of small subsystems be close
to those obtained from the microcanonical, equivalently the canonical, ensemble
for the whole system. The distinction between MITE and MATE is particularly
relevant for systems with many-body localization (MBL) for which the energy
eigenfunctions fail to be in MITE while necessarily most of them, but not all,
are in MATE. We note however that for generic macroscopic systems, including
those with MBL, most wave functions in an energy shell are in both MATE and
MITE. For a classical macroscopic system, MATE holds for most phase points on
the energy surface, but MITE fails to hold for any phase point
The promoter of the human interleukin-2 gene contains two octamer-binding sites and is partially activated by the expression of Oct-2
The gene encoding interleukin-2 (IL-2) contains a sequence 52 to 326 nucleotides upstream of its transcriptional initiation site that promotes transcription in T cells that have been activated by costimulation with tetradecanoyl phorbol myristyl acetate (TPA) and phytohemagglutinin (PHA). We found that the ubiquitous transcription factor, Oct-1, bound to two previously identified motifs within the human IL-2 enhancer, centered at nucleotides -74 and -251. Each site in the IL-2 enhancer that bound Oct-1 in vitro was also required to achieve a maximal transcriptional response to TPA plus PHA in vivo. Point mutations within either the proximal or distal octamer sequences reduced the response of the enhancer to activation by 54 and 34%, respectively. Because the murine T-cell line EL4 constitutively expresses Oct-2 and requires only TPA to induce transcription of the IL-2 gene, the effect of Oct-2 expression on activation of the IL-2 promoter in Jurkat T cells was determined. Expression of Oct-2 potentiated transcription 13-fold in response to TPA plus PHA and permitted the enhancer to respond to the single stimulus of TPA. Therefore, both the signal requirements and the magnitude of the transcription response of the IL-2 promoter can be modulated by Oct-2
Phase transitions with four-spin interactions
Using an extended Lee-Yang theorem and GKS correlation inequalities, we
prove, for a class of ferromagnetic multi-spin interactions, that they will
have a phase transition(and spontaneous magnetization) if, and only if, the
external field (and the temperature is low enough). We also show the
absence of phase transitions for some nonferromagnetic interactions. The FKG
inequalities are shown to hold for a larger class of multi-spin interactions
Location of the Lee-Yang zeros and absence of phase transitions in some Ising spin systems
We consider a class of Ising spin systems on a set \Lambda of sites. The
sites are grouped into units with the property that each site belongs to either
one or two units, and the total internal energy of the system is the sum of the
energies of the individual units, which in turn depend only on the number of up
spins in the unit. We show that under suitable conditions on these interactions
none of the |\Lambda| Lee-Yang zeros in the complex z = exp{2\beta h} plane,
where \beta is the inverse temperature and h the uniform magnetic field, touch
the positive real axis, at least for large values of \beta. In some cases one
obtains, in an appropriately taken \beta to infinity limit, a gas of hard
objects on a set \Lambda'; the fugacity for the limiting system is a rescaling
of z and the Lee-Yang zeros of the new partition function also avoid the
positive real axis. For certain forms of the energies of the individual units
the Lee-Yang zeros of both the finite- and zero-temperature systems lie on the
negative real axis for all \beta. One zero-temperature limit of this type, for
example, is a monomer-dimer system; our results thus generalize, to finite
\beta, a well-known result of Heilmann and Lieb that the Lee-Yang zeros of
monomer-dimer systems are real and negative.Comment: Plain TeX. Seventeen pages, five figures from .eps files. Version 2
corrects minor errors in version
Shaping Wikipedia editing as a teaching and learning tool to promote deep learning and information literacy
Research has shown that at least 94% of medical students use Wikipedia as an information resource (Usaid, 2012), despite medical school faculty telling them not to. In fact, medical schools do not train students to improve Wikipedia or use it critically (Azzam, 2017). The Wikiproject Medicine course was created at the invitation and in partnership with Dr. Amin Azzam at the University of California San Francisco, who started the original program in 2013. This class is offered to 4th year medical students and gives students an opportunity to edit already existing health related articles in Wikipedia to improve their quality and make them more accurate. This course enables students to improve and enrich the quality of reliable information read by patients on Wikipedia by becoming a WikiProject Medicine Editor
Thermodynamic anomalies in open quantum systems: Strong coupling effects in the isotropic XY model
The exactly solvable model of a one dimensional isotropic XY spin chain is
employed to study the thermodynamics of open systems. For this purpose the
chain is subdivided into two parts, one part is considered as the system while
the rest as the environment or bath. The equilibrium properties of the system
display several anomalous aspects such as negative entropies, negative specific
heat, negative susceptibilities in dependence of temperature and coupling
strength between system and bath. The statistical mechanics of this system is
studied in terms of a reduced density matrix. At zero temperature and for a
certain parameter values we observe a change of the ground state, a situation
akin to a quantum phase transition.Comment: 12 pages, 8 figures. Published in the special issue of Chemical
Physics "Stochastic processes in Physics and Chemistry" (in honor of Peter
H\"anggi
- …