Travel agents vs. online bookings: tackling the shortcomings of nowadays online tourism portals

In this paper we present the findings of a study that aims at identifying the reasons that let many people still rely on traditional travel agents instead of booking their trips online. The prime motivation for investigating this issue is that it is impossible to have direct experience with the product prior to consumption in the domain of tourism. The Internet provides a powerful environment for the creation of virtual representations of tourism destinations allowing indirect experience that greatly surpasses the possibilities of traditional travel agents. However, the results of the study show that social interaction with travel agents, their expertise and the possibility to save time on search can be of even higher importance. So, we derived the "best of both sides" and suggest the application of an established methodology in the area of multi-agent systems, namely 3D Electronic Institutions, to the tourism domain in order to satisfy the growing demand on human assistance related to online inquiries and to offer customers cutting-edge visualization facilities

An A4 flavor model for quarks and leptons in warped geometry

We propose a spontaneous A4 flavor symmetry breaking scheme implemented in a warped extra dimensional setup to explain the observed pattern of quark and lepton masses and mixings. The main advantages of this choice are the explanation of fermion mass hierarchies by wave function overlaps, the emergence of tribimaximal neutrino mixing and zero quark mixing at the leading order and the absence of tree-level gauge mediated flavor violations. Quark mixing is induced by the presence of bulk flavons, which allow for cross-brane interactions and a cross-talk between the quark and neutrino sectors, realizing the spontaneous symmetry breaking pattern A4 --> nothing first proposed in [X.G.\,He, Y.Y.\,Keum, R.R.\,Volkas, JHEP{0604}, 039 (2006)]. We show that the observed quark mixing pattern can be explained in a rather economical way, including the CP violating phase, with leading order cross-interactions, while the observed difference between the smallest CKM entries V_{ub} and V_{td} must arise from higher order corrections. We briefly discuss bounds on the Kaluza-Klein scale implied by flavor changing neutral current processes in our model and show that the residual little CP problem is milder than in flavor anarchic models.Comment: 34 pages, 2 figures; version published in JHE

Balance algorithm for cluster randomized trials

<p>Abstract</p> <p>Background</p> <p>Within cluster randomized trials no algorithms exist to generate a full enumeration of a block randomization, balancing for covariates across treatment arms. Furthermore, often for practical reasons multiple blocks are required to fully randomize a study, which may not have been well balanced within blocks.</p> <p>Results</p> <p>We present a convenient and easy to use randomization tool to undertake allocation concealed block randomization. Our algorithm highlights allocations that minimize imbalance between treatment groups across multiple baseline covariates.</p> <p>We demonstrate the algorithm using a cluster randomized trial in primary care (the PRE-EMPT Study) and show that the software incorporates a trade off between independent random allocations that were likely to be imbalanced, and predictable deterministic approaches that would minimise imbalance. We extend the methodology of single block randomization to allocate to multiple blocks conditioning on previous allocations.</p> <p>Conclusion</p> <p>The algorithm is included as Additional file <supplr sid="S1">1</supplr> and we advocate its use for robust randomization within cluster randomized trials.</p> <suppl id="S1"> <title> <p>Additional File 1</p> </title> <text> <p><b>Cluster randomization allocation algorithm version 1.</b> Algorithms scripted in R to provide robust cluster randomization.</p> </text> <file name="1471-2288-8-65-S1.zip"> <p>Click here for file</p> </file> </suppl

MINLO: Multi-scale improved NLO

In the present work we consider the assignment of the factorization and renormalization scales in hadron collider processes with associated jet production, at next-to-leading order (NLO) in perturbation theory. We propose a simple, definite prescription to this end, including Sudakov form factors to consistently account for the distinct kinematic scales occuring in such collisions. The scheme yields results that are accurate at NLO and, for a large class of observables, it resums to all orders the large logarithms that arise from kinematic configurations involving disparate scales. In practical terms the method is most simply understood as an NLO extension of the matrix element reweighting procedure employed in tree level matrix element-parton shower merging algorithms. By way of a proof-of-concept, we apply the method to Higgs and Z boson production in association with up to two jets.Comment: 27 pages, 17 figure

Prognostic value of lymph node ratio and extramural vascular invasion on survival for patients undergoing curative colon cancer resection

There was no study funding. We are grateful to Tony Rafferty (Tailored Information for the People of Scotland, TIPs) for providing survival data.Peer reviewedPublisher PD

Tailoring the atomic structure of graphene nanoribbons by STM lithography

The practical realization of nano-scale electronics faces two major challenges: the precise engineering of the building blocks and their assembly into functional circuits. In spite of the exceptional electronic properties of carbon nanotubes only basic demonstration-devices have been realized by time-consuming processes. This is mainly due to the lack of selective growth and reliable assembly processes for nanotubes. However, graphene offers an attractive alternative. Here we report the patterning of graphene nanoribbons (GNRs) and bent junctions with nanometer precision, well-defined widths and predetermined crystallographic orientations allowing us to fully engineer their electronic structure using scanning tunneling microscope (STM) lithography. The atomic structure and electronic properties of the ribbons have been investigated by STM and tunneling spectroscopy measurements. Opening of confinement gaps up to 0.5 eV, allowing room temperature operation of GNR-based devices, is reported. This method avoids the difficulties of assembling nano-scale components and allows the realization of complete integrated circuits, operating as room temperature ballistic electronic devices.Comment: 8 pages text, 5 figures, Nature Nanotechnology, in pres

On the relative expressiveness of higher-order session processes

By integrating constructs from the λ-calculus and the π-calculus, in higher-order process calculi exchanged values may contain processes. This paper studies the relative expressiveness of HOπ, the higher-order π-calculus in which communications are governed by session types. Our main discovery is that HO, a subcalculus of HOπ which lacks name-passing and recursion, can serve as a new core calculus for session-typed higher-order concurrency. By exploring a new bisimulation for HO, we show that HO can encode HOπ fully abstractly (up to typed contextual equivalence) more precisely and efficiently than the first-order session π-calculus (π). Overall, under session types, HOπ, HO, and π are equally expressive; however, HOπ and HO are more tightly related than HOπ and π

Nanomechanical Detection of Itinerant Electron Spin Flip

Spin is an intrinsically quantum property, characterized by angular momentum. A change in the spin state is equivalent to a change in the angular momentum or mechanical torque. This spin-induced torque has been invoked as the intrinsic mechanism in experiments ranging from the measurements of angular momentum of photons g-factor of metals and magnetic resonance to the magnetization reversal in magnetic multi-layers A spin-polarized current introduced into a nonmagnetic nanowire produces a torque associated with the itinerant electron spin flip. Here, we report direct measurement of this mechanical torque and itinerant electron spin polarization in an integrated nanoscale torsion oscillator, which could yield new information on the itinerancy of the d-band electrons. The unprecedented torque sensitivity of 10^{-22} N m/ \sqrt{Hz} may enable applications for spintronics, precision measurements of CP-violating forces, untwisting of DNA and torque generating molecules.Comment: 14 pages, 4 figures. visit http://nano.bu.edu/ for related paper

Pathomechanisms of ulnar ligament lesions of the wrist in a cadaveric distal radius fracture model

Background and purpose: Mechanisms of injury to ulnar sided ligaments, stabilizing the distal radioulnar joint and the ulna to the carpus, associated with dorsally displaced distal radius fractures are poorly described. We investigated the injury patterns in a human cadaver fracture model. Methods: Fresh frozen human cadaver arms were used. A dorsal open wedge osteotomy was made in the distal radius. In 8 specimens pressure was applied to the palm with the wrist in dorsiflexion and ulnar sided stabilizing structures subsequently severed. Dorsal angulation was measured on digitized radiographs. In 8 more specimens the triangular fibrocartilage complex was forced into rupture by axially loading the forearm with the wrist in dorsiflexion. The ulnar side was dissected and injuries were recorded. Results: Intact ulnar soft tissues limited the dorsal angulation of the distal radius fragment to a median of 32o (16-34o). A combination of bending and shearing of the distal radius fragment was needed to create TFCC injuries. Both palmar and dorsal injuries were observed simultaneously in 6/8 specimens. Interpretation: A TFCC injury can be expected when dorsal angulation of a distal radius fracture exceeds 32o. The extensor carpi ulnaris subsheath may be a functionally integral part of the TFCC. Both dorsal and palmar structures can tear simultaneously. These findings may have implications for reconstruction of ulnar sided soft tissue injuries

Probing the close environment of young stellar objects with interferometry

The study of Young Stellar Objects (YSOs) is one of the most exciting topics that can be undertaken by long baseline optical interferometry. The magnitudes of these objects are at the edge of capabilities of current optical interferometers, limiting the studies to a few dozen, but are well within the capability of coming large aperture interferometers like the VLT Interferometer, the Keck Interferometer, the Large Binocular Telescope or 'OHANA. The milli-arcsecond spatial resolution reached by interferometry probes the very close environment of young stars, down to a tenth of an astronomical unit. In this paper, I review the different aspects of star formation that can be tackled by interferometry: circumstellar disks, multiplicity, jets. I present recent observations performed with operational infrared interferometers, IOTA, PTI and ISI, and I show why in the next future one will extend these studies with large aperture interferometers.Comment: Review to be published in JENAM'2002 proceedings "The Very Large Telescope Interferometer Challenges for the future