3,112 research outputs found
Concepções dos acadêmicos sobre a evasão do curso de licenciatura em química na Universidade Tecnológica Federal do Paraná – Campus Medianeira
Anais do II Seminário Seminário Estadual PIBID do Paraná: tecendo saberes / organizado por Dulcyene Maria Ribeiro e Catarina Costa Fernandes — Foz do Iguaçu: Unioeste; Unila, 2014A evasão escolar tem sido tema de diversos estudos no Brasil e têm
aumentado significativamente no Ensino Superior. Em média, dois em cada dez
estudantes brasileiros desistem do curso superior que iniciaram (SIMAS, 2012). Dessa
forma, este trabalho foi realizado com a intenção de analisar o motivo da evasão dos
acadêmicos do curso de Licenciatura em Química da Universidade Tecnológica Federal
do Paraná (UTFPR) – Câmpus Medianeira. Para isso foi aplicado um questionário para
os acadêmicos do curso. Com a aplicação do questionário, o gosto por química e a
perspectivas do mercado de trabalho são motivos determinantes para a permanência dos
acadêmicos no curso. Já a dificuldade com as disciplinas de matemática presente nos
semestres iniciais do curso e dificuldade de conciliar trabalho e estudos seriam as
principais causas da evasã
On the Convergence of the Electronic Structure Properties of the FCC Americium (001) Surface
Electronic and magnetic properties of the fcc Americium (001) surface have
been investigated via full-potential all-electron density-functional electronic
structure calculations at both scalar and fully relativistic levels. Effects of
various theoretical approximations on the fcc Am (001) surface properties have
been thoroughly examined. The ground state of fcc Am (001) surface is found to
be anti-ferromagnetic with spin-orbit coupling included (AFM-SO). At the ground
state, the magnetic moment of fcc Am (001) surface is predicted to be zero. Our
current study predicts the semi-infinite surface energy and the work function
for fcc Am (001) surface at the ground state to be approximately 0.82 J/m2 and
2.93 eV respectively. In addition, the quantum size effects of surface energy
and work function on the fcc Am (001) surface have been examined up to 7 layers
at various theoretical levels. Results indicate that a three layer film surface
model may be sufficient for future atomic and molecular adsorption studies on
the fcc Am (001) surface, if the primary quantity of interest is the
chemisorption energy.Comment: 34 pages, 9 figure
Clinical trial of laronidase in Hurler syndrome after hematopoietic cell transplantation.
BackgroundMucopolysaccharidosis I (MPS IH) is a lysosomal storage disease treated with hematopoietic cell transplantation (HCT) because it stabilizes cognitive deterioration, but is insufficient to alleviate all somatic manifestations. Intravenous laronidase improves somatic burden in attenuated MPS I. It is unknown whether laronidase can improve somatic disease following HCT in MPS IH. The objective of this study was to evaluate the effects of laronidase on somatic outcomes of patients with MPS IH previously treated with HCT.MethodsThis 2-year open-label pilot study of laronidase included ten patients (age 5-13 years) who were at least 2 years post-HCT and donor engrafted. Outcomes were assessed semi-annually and compared to historic controls.ResultsThe two youngest participants had a statistically significant improvement in growth compared to controls. Development of persistent high-titer anti-drug antibodies (ADA) was associated with poorer 6-min walk test (6MWT) performance; when patients with high ADA titers were excluded, there was a significant improvement in the 6MWT in the remaining seven patients.ConclusionsLaronidase seemed to improve growth in participants <8 years old, and 6MWT performance in participants without ADA. Given the small number of patients treated in this pilot study, additional study is needed before definitive conclusions can be made
No neon, but jets in the remarkable recurrent nova M31N 2008-12a? - Hubble Space Telescope spectroscopy of the 2015 eruption
The 2008 discovery of an eruption of M31N 2008-12a began a journey on which the true nature of this remarkable recurrent nova continues to be revealed. M31N 2008-12a contains a white dwarf close to the Chandrasekhar limit, accreting at a high rate from its companion, and undergoes thermonuclear eruptions which are observed yearly and may even be twice as frequent. In this paper, we report on Hubble Space Telescope STIS UV spectroscopy taken within days of the predicted 2015 eruption, coupled with Keck spectroscopy of the 2013 eruption. Together, this spectroscopy permits the reddening to be constrained to E(B-V) = 0.10 +/- 0.03. The UV spectroscopy reveals evidence for highly ionized, structured, and high velocity ejecta at early times. No evidence for neon is seen in these spectra however, but it may be that little insight can be gained regarding the composition of the white dwarf (CO vs ONe)
Bio-nanotechnology application in wastewater treatment
The nanoparticles have received high interest in the field of medicine and water purification, however, the nanomaterials produced by chemical and physical methods are considered hazardous, expensive, and leave behind harmful substances to the environment. This chapter aimed to focus on green-synthesized nanoparticles and their medical applications. Moreover, the chapter highlighted the applicability of the metallic nanoparticles (MNPs) in the inactivation of microbial cells due to their high surface and small particle size. Modifying nanomaterials produced by green-methods is safe, inexpensive, and easy. Therefore, the control and modification of nanoparticles and their properties were also discussed
Re-structuring of marine communities exposed to environmental change
Species richness is the most commonly used but controversial biodiversity metric in studies on aspects of community stability such as structural composition or productivity. The apparent ambiguity of theoretical and experimental findings may in part be due to experimental shortcomings and/or heterogeneity of scales and methods in earlier studies. This has led to an urgent call for improved and more realistic experiments. In a series of experiments replicated at a global scale we translocated several hundred marine hard bottom communities to new environments simulating a rapid but moderate environmental change. Subsequently, we measured their rate of compositional change (re-structuring) which in the great majority of cases represented a compositional convergence towards local communities. Re-structuring is driven by mortality of community components (original species) and establishment of new species in the changed environmental context. The rate of this re-structuring was then related to various system properties. We show that availability of free substratum relates negatively while taxon richness relates positively to structural persistence (i.e., no or slow re-structuring). Thus, when faced with environmental change, taxon-rich communities retain their original composition longer than taxon-poor communities. The effect of taxon richness, however, interacts with another aspect of diversity, functional richness. Indeed, taxon richness relates positively to persistence in functionally depauperate communities, but not in functionally diverse communities. The interaction between taxonomic and functional diversity with regard to the behaviour of communities exposed to environmental stress may help understand some of the seemingly contrasting findings of past research
No neon, but jets in the remarkable recurrent nova M31N 2008-12a? - Hubble Space Telescope spectroscopy of the 2015 eruption
The 2008 discovery of an eruption of M31N 2008-12a began a journey on which the true nature of this remarkable recurrent nova continues to be revealed. M31N 2008-12a contains a white dwarf close to the Chandrasekhar limit, accreting at a high rate from its companion, and undergoes thermonuclear eruptions which are observed yearly and may even be twice as frequent. In this paper, we report on Hubble Space Telescope STIS UV spectroscopy taken within days of the predicted 2015 eruption, coupled with Keck spectroscopy of the 2013 eruption. Together, this spectroscopy permits the reddening to be constrained to E(B-V) = 0.10 +/- 0.03. The UV spectroscopy reveals evidence for highly ionized, structured, and high velocity ejecta at early times. No evidence for neon is seen in these spectra however, but it may be that little insight can be gained regarding the composition of the white dwarf (CO vs ONe)
Mid-infrared plasmons in scaled graphene nanostructures
Plasmonics takes advantage of the collective response of electrons to
electromagnetic waves, enabling dramatic scaling of optical devices beyond the
diffraction limit. Here, we demonstrate the mid-infrared (4 to 15 microns)
plasmons in deeply scaled graphene nanostructures down to 50 nm, more than 100
times smaller than the on-resonance light wavelength in free space. We reveal,
for the first time, the crucial damping channels of graphene plasmons via its
intrinsic optical phonons and scattering from the edges. A plasmon lifetime of
20 femto-seconds and smaller is observed, when damping through the emission of
an optical phonon is allowed. Furthermore, the surface polar phonons in SiO2
substrate underneath the graphene nanostructures lead to a significantly
modified plasmon dispersion and damping, in contrast to a non-polar
diamond-like-carbon (DLC) substrate. Much reduced damping is realized when the
plasmon resonance frequencies are close to the polar phonon frequencies. Our
study paves the way for applications of graphene in plasmonic waveguides,
modulators and detectors in an unprecedentedly broad wavelength range from
sub-terahertz to mid-infrared.Comment: submitte
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
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