410 research outputs found
Footprints in the sky: using student track logs from a "bird's eye view" virtual field trip to enhance learning
Research into virtual field trips (VFTs) started in the 1990s but, only recently, the maturing technology of devices and networks has made them viable options for educational settings. By considering an experiment, the learning benefits of logging the movement of students within a VFT are shown. The data are visualized by two techniques: âanimated path mapsâ are dynamic animations of students' movement in a VFT; âpaint spray mapsâ show where students concentrated their visual attention and are static. A technique for producing these visualizations is described and the educational use of tracking data in VFTs is critically discussed
Exact Lagrangian submanifolds in simply-connected cotangent bundles
We consider exact Lagrangian submanifolds in cotangent bundles. Under certain
additional restrictions (triviality of the fundamental group of the cotangent
bundle, and of the Maslov class and second Stiefel-Whitney class of the
Lagrangian submanifold) we prove such submanifolds are Floer-cohomologically
indistinguishable from the zero-section. This implies strong restrictions on
their topology. An essentially equivalent result was recently proved
independently by Nadler, using a different approach.Comment: 28 pages, 3 figures. Version 2 -- derivation and discussion of the
spectral sequence considerably expanded. Other minor change
Renal colic in a dialysis patient: a case of renal stone disease
Renal colic in a dialysis patient: a case of renal stone diseas
Displacement energy of unit disk cotangent bundles
We give an upper bound of a Hamiltonian displacement energy of a unit disk
cotangent bundle in a cotangent bundle , when the base manifold
is an open Riemannian manifold. Our main result is that the displacement
energy is not greater than , where is the inner radius of ,
and is a dimensional constant. As an immediate application, we study
symplectic embedding problems of unit disk cotangent bundles. Moreover,
combined with results in symplectic geometry, our main result shows the
existence of short periodic billiard trajectories and short geodesic loops.Comment: Title slightly changed. Close to the version published online in Math
Zei
Capital account regulations and the trading system: a compatibility review
This repository item contains a single issue of the Pardee Center Task Force Reports, a publication series that began publishing in 2009 by the Boston University Frederick S. Pardee Center for the Study of the Longer-Range Future. Spanish version produced by the Center for the Study of State and Society, Buenos Aires.
Portuguese version coordinated by Daniela Magalhaes Prates, a contributing author of the report, in collaboration with Ana Trivellato (translator), and Maria InĂȘs Amorozo (graphic designer).This report is the product of the Pardee Center Task Force on Regulating Capital Flows for Long-Run Development and builds on the Task ForceÂŽs first report published in March 2012.
The Pardee Center Task Force was convened initially in September 2011 as consensus was emerging that the global financial crisis has re-confirmed the need to regulate cross-border finance. The March 2012 report argues that international financial institutions â and in particular the International Monetary Fund â need to support measures that would allow capital account regulations (CARs) to become a standard and effective part of the macroeconomic policy toolkit. Yet some policymakers and academics expressed concern that many nations â and especially developing countries â may not have the flexibility to adequately deploy such regulations because of trade and investment treaties they are party to.
In June 2012, the Pardee Center, with the Center for the Study of State and Society (CEDES) in Argentina and Global Development and Environment Institute (GDAE) at Tufts University, convened a second Task Force workshop in Buenos Aires specifically to review agreements at the WTO and various Free Trade Agreements (FTAs) and Bilateral Investment Treaties (BITs) for the extent to which the trading regime is compatible with the ability to deploy effective capital account regulations. This report presents the findings of that review, and highlights a number of potential incompatibilities found between the trade and investment treaties and the ability to deploy CARs. It also highlights an alarming lack of policy space to use CARs under a variety of FTAs and BITsâespecially those involving the United States. Like the first report, it was written by an international group of experts whose goal is to help inform discussions and decisions by policymakers at the IMF and elsewhere that will have implications for the economic health and development trajectories for countries around the world
Predictors of unemployment status in people with relapsing multiple sclerosis: a single center experience
Background: Multiple sclerosis (MS) is the most common cause of nontraumatic chronic neurological disability affecting young adults during their crucial employment years. Objectives: To evaluate patients and disease related factors associated to unemployment in a cohort of relapsingâremitting (RR) MS patients. Methods: We included RRMS patients with a follow-up of at least 1 year. We collected data about years of school education and employment status. Patients underwent a neuropsychological evaluation using the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS). Demographic and clinical predictors of unemployment were assessed through a multivariable stepwise logistic regression model. Results: We evaluated 260 consecutive RRMS patients. Employed patients were less frequently female (68.4% vs 83.3%, p = 0.006), less disabled (median Expanded Disability Status Scale (EDSS) score: 2.0 (0â7.0) vs 2.5 (0â7.5), p < 0.001), with more years of school education (mean ± standard deviation (SD), years: 13.74 ± 0.30 vs 10.86 ± 3.47, p < 0.001). Female sex and a higher EDSS score resulted associated with a greater risk of unemployment (OR 3.510, 95% CI 1.654â7.448, p = 0.001; OR 1.366, 95% CI 1.074â1.737, p = 0.011, respectively), whereas a greater number of years of schooling and current disease-modifying therapy exposure resulted protective factors (OR 0.788, 95% CI 0.723â0.858, p < 0,001; OR 0.414, 95% CI 0.217â0.790, p = 0.008, respectively). Conclusions: Understanding work is pervasively influenced by consequences of MS, we confirmed the impact of demographic, physical, and cognitive factors on employment status in RRMS patients
Integrated Multidisciplinary Approach for the Study of the Geothermal Potential of Umbria (Central Italy)
Photoluminiscence enhancement in quaternay III-nitrides alloys grown by molecular beam epitaxy with increasing Al content
Room temperature photoluminescence and optical absorption spectra have been measured in wurtzite InxAlyGa1âxâyN (x ⌠0.06, 0.02<y<0.27) layers grown by molecular beam epitaxy. Photoluminescence spectra show both an enhancement of the integrated intensity and an increasing Stokes shift with the Al content. Both effects arise from an Al-enhanced exciton localization revealed by the S- and W-shaped temperature dependences of the photoluminescence emission energy and bandwidth, respectively. Present results point to these materials as a promising choice for the active region in efficient light emitters. An In-related bowing parameter of 1.6âeV was derived from optical absorption data
The "Symplectic Camel Principle" and Semiclassical Mechanics
Gromov's nonsqueezing theorem, aka the property of the symplectic camel,
leads to a very simple semiclassical quantiuzation scheme by imposing that the
only "physically admissible" semiclassical phase space states are those whose
symplectic capacity (in a sense to be precised) is nh + (1/2)h where h is
Planck's constant. We the construct semiclassical waveforms on Lagrangian
submanifolds using the properties of the Leray-Maslov index, which allows us to
define the argument of the square root of a de Rham form.Comment: no figures. to appear in J. Phys. Math A. (2002
- âŠ