4,587 research outputs found
Complementary action of chemical and electrical synapses to perception
Acknowledgements This study was possible by partial financial support from the following agencies: Fundação Araucária, EPSRC-EP/I032606/1, CNPq No. 441553/2014-1, CAPES No. 17656-12-5 and Science Without Borders Program— Process Nos. 17656125, 99999.010583/2013-00 and 245377/2012-3.Peer reviewedPostprin
Towards absolute calibration of optical tweezers
Aiming at absolute force calibration of optical tweezers, following a
critical review of proposed theoretical models, we present and test the results
of MDSA (Mie-Debye-Spherical Aberration) theory, an extension of a previous
(MD) model, taking account of spherical aberration at the glass/water
interface. This first-principles theory is formulated entirely in terms of
experimentally accessible parameters (none adjustable). Careful experimental
tests of the MDSA theory, undertaken at two laboratories, with very different
setups, are described. A detailed description is given of the procedures
employed to measure laser beam waist, local beam power at the transparent
microspheres trapped by the tweezers, microsphere radius and the trap
transverse stiffness, as a function of radius and height in the (inverted
microscope) sample chamber. We find generally very good agreement with MDSA
theory predictions, for a wide size range, from the Rayleigh domain to large
radii, including the values most often employed in practice, and at different
chamber heights, both with objective overfilling and underfilling. The results
asymptotically approach geometrical optics in the mean over size intervals, as
they should, and this already happens for size parameters not much larger than
unity. MDSA predictions for the trapping threshold, position of stiffness peak,
stiffness variation with height, multiple equilibrium points and `hopping'
effects among them are verified. Remaining discrepancies are ascribed to focus
degradation, possibly arising from objective aberrations in the infrared, not
yet included in MDSA theory.Comment: 15 pages, 20 figure
Employability and Higher Education: The Case Study of ESTM Master's Degree
The labor market in this globalized world, based on new technologies, is constantly changing. In an
increasingly demanding and dynamic world of human resources competences, young people have to
focus on their training in order to enter in the labor market better prepared and thus contribute to the
success of the entity that receives them and for their own professional and personal fulfillment. The
choice of their academic journey is crucial to ensure the achievement of these competences and make
that decision is not easy, with a system of higher education such as the Portuguese, where there are so
many graduation courses and two systems of teaching, University and Polytechnic. In fact, with the
changes introduced in higher education by the so-called Bologna Process, most undergraduate’s
courses saw the number of years reduced from five to three years, while others opted for integrated
master's degrees. In the case of the School of Tourism and Maritime Technology, the option was to offer
three-year degree courses and two-year master's degrees. This study intends to understand where are
the students who have bet on their training at the master's level and finish their master's degree at the
School of Tourism and Maritime Technology (ESTM) of the Polytechnic of Leiria, if they are working in
the area and if the employers recognize these qualifications.info:eu-repo/semantics/publishedVersio
Infinitely Many Stochastically Stable Attractors
Let f be a diffeomorphism of a compact finite dimensional boundaryless
manifold M exhibiting infinitely many coexisting attractors. Assume that each
attractor supports a stochastically stable probability measure and that the
union of the basins of attraction of each attractor covers Lebesgue almost all
points of M. We prove that the time averages of almost all orbits under random
perturbations are given by a finite number of probability measures. Moreover
these probability measures are close to the probability measures supported by
the attractors when the perturbations are close to the original map f.Comment: 14 pages, 2 figure
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Aplicação de Análise e Modelagem Multidimensional para o Monitoramento de Resíduos Sólidos Industriais
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