2,119 research outputs found
Transfer matrix solution of the Wako-Sait\^o-Mu\~noz-Eaton model augmented by arbitrary short range interactions
The Wako-Sait{\^o}-Mu\~noz-Eaton (WSME) model, initially introduced in the
theory of protein folding, has also been used in modeling the RNA folding and
some epitaxial phenomena. The advantage of this model is that it admits exact
solution in the general inhomogeneous case (Bruscolini and Pelizzola, 2002)
which facilitates the study of realistic systems. However, a shortcoming of the
model is that it accounts only for interactions within continuous stretches of
native bonds or atomic chains while neglecting interstretch (interchain)
interactions. But due to the biopolymer (atomic chain) flexibility, the
monomers (atoms) separated by several non-native bonds along the sequence can
become closely spaced. This produces their strong interaction. The inclusion of
non-WSME interactions into the model makes the model more realistic and
improves its performance. In this study we add arbitrary interactions of finite
range and solve the new model by means of the transfer matrix technique. We can
therefore exactly account for the interactions which in proteomics are
classified as medium- and moderately long-range ones.Comment: 15 pages, 2 figure
ALMA Observations of the Young Substellar Binary System 2M1207
We present ALMA observations of the 2M1207 system, a young binary made of a
brown dwarf with a planetary-mass companion at a projected separation of about
40 au. We detect emission from dust continuum at 0.89 mm and from the rotational transition of CO from a very compact disk around the young brown
dwarf. The small radius found for this brown dwarf disk may be due to
truncation from the tidal interaction with the planetary-mass companion. Under
the assumption of optically thin dust emission, we estimated a dust mass of 0.1
for the 2M1207A disk, and a 3 upper limit of for dust surrounding 2M1207b, which is the tightest upper
limit obtained so far for the mass of dust particles surrounding a young
planetary-mass companion. We discuss the impact of this and other
non-detections of young planetary-mass companions for models of planet
formation, which predict the presence of circum-planetary material surrounding
these objects.Comment: 10 pages, 6 figures, accepted for publication in A
Research on the Geography of Agricultural Change: Redundant or Revitalized?
Future research directions for agricultural geography were the subject of debate in Area in the late 1980s. The subsequent application of political economy ideas undoubtedly revived interest in agricultural research. This paper argues that agricultural geography contains greater diversity than the dominant political economy discourse would suggest. It reviews âotherâ areas of agricultural research on policy, post-productivism, people, culture and animals, presenting future suggestions for research. They should ensure that agricultural research continues revitalized rather than redundant into the next millennium
Heavy Baryon Production and Decay
The branching ratio B(Lambda_c -> p K- pi+) normalizes the production and
decay of charmed and bottom baryons. At present, this crucial branching ratio
is extracted dominantly from B.bar -> baryons analyses. This note questions
several of the underlying assumptions and predicts sizable B.bar -> D(*) N
N'.bar X transitions, which were traditionally neglected. It predicts
B(Lambda_c -> p K- pi+) to be significantly larger (0.07 +/- 0.02) than the
world average. Some consequences are briefly mentioned. Several techniques to
measure B(Lambda_c -> p K- pi+) are outlined with existing or soon available
data samples. By equating two recent CLEO results, an appendix obtains B(D0 ->
K- pi+)= 0.035 +/- 0.002, which is somewhat smaller than the current world
average.Comment: 27 pages, 4 eps figures, revte
Proceedings of the Semantics of African, Asian and Austronesian Languages (TripleA) 2
TripleA is a workshop series founded by linguists from the University of TĂŒbingen and the University of Potsdam. Its aim is to provide a forum for semanticists doing fieldwork on understudied languages, and its focus is on languages from Africa, Asia, Australia and Oceania. The second TripleA workshop was held at the University of Potsdam, June 3-5, 2015
Multi-Modal Stories: LIS Students Explore Reading, Literacy, and Library Service Through the Lens of âThe 39 Cluesâ
The article presents a conceptual framework for exploring multi-modal stories for children using the childrenâs adventure series, The 39 Clues. The framework is accompanied by concrete examples of student learning experiences, in the form of student reflections on issues related to the convergence of media and the nature of reading and childrenâs library service in the 21st century. The article begins with a look at the series, The 39 Clues, describing its history and its format. It then provides a framework for exploring some of the issues related to reading The 39 Clues, first, by introducing some concepts from the literature associated with reading in the digital world and then, outlining some of the practical concerns that librarians might have in relation to The 39 Clues. The article then presents the reflections of five students â one MLIS student and four PhD students â who considered multi-modal stories in light of their future practice, research, and teaching in LIS. The article concludes by summarizing five over-arching themes that emerged from the studentsâ explorations - reading as a two-track experience, questions about authorship, evaluation skills needed to review multimodal stories, opportunities for information literacy instruction, and access and equity issues
The Kalman-Tran-D'Souza Model and the Semileptonic Decay Rates of Heavy Baryons
We present an investigation of the inclusive semileptonic decay widths of the
heavy baryons Lambda_Q and Xi_Q, (Q=b,c) performed within a relativistic
constituent quark model, formulated on the light-front. In a way conceptually
similar to the deep-inelastic scattering case, the H_Q baryon inclusive width
is expressed as the integral of the free Q-quark partial width multiplied by a
bound-state factor related to the Q-quark distribution function in the H_Q. The
non-perturbative meson structure is described through the quark-model wave
functions, constructed via the Hamiltonian light-front formalism using as input
the Kalman-Tran-D'Souza equal time wave functions. A link between spectroscopic
quark models and the H_Q decay physics is obtained in this way. It is shown
that the bound-state effects and the Fermi motion of the b-quark remarkably
reduce the decay rate with respect to the free-quark result. Our predictions
for the BR(Lambda_c ->X_s e nu_e) and BR(Lambda_b->X_c e nu_e) decays are in
good agreement with existing data.Comment: 6 pages, latex, espcrc2.sty (included), 3 figures. The invited talk
presented by C.S.K. at the 4-th International Conference on Hyperons, Charm
and Beauty Hadrons, Valencia, June 27-30, 200
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