16,932 research outputs found
BACK PAIN AND THE POSTURAL AND BEHAVIORAL HABITS OF STUDENTS IN THE MUNICIPAL SCHOOL NETWORK OF TEUTÔNIA, RIO GRANDE DO SUL
to investigate the prevalence of back pain during a prior three-month period; to identify postural and behavioral habits; to assess whether a relationship exists between back pain and the postural and behavioral habits of elementary school students in the municipal school network in the city of Teutônia, Rio Grande do Sul (RS). METHODS: this was an epidemiological population study in which 833 5th to 8th grade students from schools in the municipal school network in Teutônia participated. The students completed a Back Pain and Body Posture Evaluation Instrument (BackPEI) questionnaire that assessed back pain and postural and behavioral habits. The analysis was performed using descriptive statistics, calculating prevalence ratios (PR) and confidence intervals at the 95% level. The dependent variable was back pain, and the independent variables were postural and behavioral habits. The PR was calculated using a multivariate analysis with robust variance (α = 0.05). RESULTS: the prevalence of back pain in the previous three months was 54.1%. The majority of students reported feeling pain once per month, and 17.4% of the students reported that pain impaired their performance of daily activities. The multivariate analysis showed a correlation between back pain and time spent per day watching television (p = 0.046), sleeping posture (p = 0.048) and sitting Down to write (p = 0.032). CONCLUSIONS: these results demonstrate a high prevalence of back pain in schoolchildren, suggesting an urgent need to develop educational and preventative programs in schools
A utilitarian antagonist: the zombie in popular video games
This article takes as its starting point the prevalence of the zombie in video games. I argue that, although the zombie games often superficially resemble filmic texts in their use of aesthetic and narrative, they must be understood, less as a set of conventions and thematic metaphors in the way that the zombie text has been read in film and television scholarship, and more as a utilisation of the zombie as a utilitarian antagonist that facilitates and permits the pleasures of violence and fantasy in video game play. Beginning with the Resident Evil and Left 4 Dead series of games I examine the way that games necessarily update the notion zombie as mass antagonist via the need to vary gameplay activity through different styles of adversary for players. At the same time I will demonstrate that, far from simply being the province of the survival horror genre, the zombie appears across an array of game forms, game cultures and game productions. The zombie highlights the participatory nature of game culture in the array of zombie 'mods' that users create to transform existing games into zombie based games, in particular in relation to titles such as the Call of Duty series. At the other end of the production spectrum the zombie features heavily in the little studied area of online flash games where the zombie can be found in a variety of game genres and forms. The zombie here often operates as a pastiche of popular zombie narratives in survival games (The Last Stand), parodic engagements with zombie conventions (Jetpacks and Zombies) or play with the notion of zombie pandemics (the Infectionator games). Here I situate the zombie game as a aesthetic genre that works to provide an easily understandable context for such interactive genres as survival horror, text adventures, shooting games, physics games and driving games, with the popularity of these enough to drive numerous dedicated hosting and link sites such as zombiegames.net. The pastiche element of these games extends into gamers social engagement with games. Online debates over the the appropriate actions or preparation for a zombie holocaust are commonplace on the internet in such spaces as Zombieresearch.net. Whilst many of these sites feature decidedly tongue in cheek engagement with the notion of the zombie apocalypse, the users of fora for games like Left 4 Dead and Dead Island tend to debate this directly in the terms of the games themselves, discussing their relative merits or realism. Some of these games also highlight the specific pleasures of identifying the zombie as protagonist of sorts. In discussing this I will return to online gaming and the Left 4 Dead games in which players may compete online as part of the zombie horde. Such games raise major questions for the issues of identification and immersion that are said to be at the centre of the game experience. I will also explore the parodic pleasures of many flash games that situate the player in the role of spreading zombie infections. Throughout this article I aim to demonstrate that the zombie in game culture is less a cultural metaphor than a combination of utilitarian antagonist and a persistent aesthetic; a means of providing style or pleasure to many games that relies on the intertextual and flexible nature of the zombie as popular cultural phenomenon
Sistemas agroflorestais: potencial para sequestro de carbono e produção de outros serviços ambientais.
bitstream/item/68494/1/093-Sistemas-agroflorestais-potencial-para-sequestro-de-carbono.pdfPublicado também no Cadernos de Agroecologia, v. 7, n. 2, 2012
Multi-mode bosonic Gaussian channels
A complete analysis of multi-mode bosonic Gaussian channels is proposed. We
clarify the structure of unitary dilations of general Gaussian channels
involving any number of bosonic modes and present a normal form. The maximum
number of auxiliary modes that is needed is identified, including all rank
deficient cases, and the specific role of additive classical noise is
highlighted. By using this analysis, we derive a canonical matrix form of the
noisy evolution of n-mode bosonic Gaussian channels and of their weak
complementary counterparts, based on a recent generalization of the normal mode
decomposition for non-symmetric or locality constrained situations. It allows
us to simplify the weak-degradability classification. Moreover, we investigate
the structure of some singular multi-mode channels, like the additive classical
noise channel that can be used to decompose a noisy channel in terms of a less
noisy one in order to find new sets of maps with zero quantum capacity.
Finally, the two-mode case is analyzed in detail. By exploiting the composition
rules of two-mode maps and the fact that anti-degradable channels cannot be
used to transfer quantum information, we identify sets of two-mode bosonic
channels with zero capacity.Comment: 37 pages, 3 figures (minor editing), accepted for publication in New
Journal of Physic
SkyMapper Southern Survey: First Data Release (DR1)
We present the first data release (DR1) of the SkyMapper Southern Survey, a
hemispheric survey carried out with the SkyMapper Telescope at Siding Spring
Observatory in Australia. Here, we present the survey strategy, data
processing, catalogue construction and database schema. The DR1 dataset
includes over 66,000 images from the Shallow Survey component, covering an area
of 17,200 deg in all six SkyMapper passbands , while the full area
covered by any passband exceeds 20,000 deg. The catalogues contain over 285
million unique astrophysical objects, complete to roughly 18 mag in all bands.
We compare our point-source photometry with PanSTARRS1 DR1 and note an
RMS scatter of 2%. The internal reproducibility of SkyMapper photometry is on
the order of 1%. Astrometric precision is better than 0.2 arcsec based on
comparison with Gaia DR1. We describe the end-user database, through which data
are presented to the world community, and provide some illustrative science
queries.Comment: 31 pages, 19 figures, 10 tables, PASA, accepte
INTRAEMPREENDEDORISMO EM INSTITUIÇÕES DE ENSINO PÚBLICO: O CASO DA UNIVERSIDADE FEDERAL DE SANTA CATARINA - UFSC
As organizações necessitam de profissionais capacitados para criar e inovar em suas funções. Mas para que isso ocorra, é fundamental o incentivo por meio de treinamentos, para possibilitar o desenvolvimento de intraempreendedores. Podemos observar uma gama de pesquisas voltadas as organizações enfatizando a importância de pessoas qualificadas. No entanto, instituições universitárias, faculdades, institutos e centros de educação, também precisam de profissionais qualificados, pois são espaços de excelência em formação de profissionais para o mercado de trabalho. Incentivar a formação das competências dos funcionários para serem intraempreendedores inovadores pode ser uma forma de facilitar o caminho para o alcance dos objetivos da instituição. O artigo tras a luz um caso de treinamento e desenvolvimento de intraempreendedores, realizado com colaboradores técnico-administrativos da Universidade Federal de Santa Catarina
Growth model with restricted surface relaxation
We simulate a growth model with restricted surface relaxation process in d=1
and d=2, where d is the dimensionality of a flat substrate. In this model, each
particle can relax on the surface to a local minimum, as the Edwards-Wilkinson
linear model, but only within a distance s. If the local minimum is out from
this distance, the particle evaporates through a refuse mechanism similar to
the Kim-Kosterlitz nonlinear model. In d=1, the growth exponent beta, measured
from the temporal behavior of roughness, indicates that in the coarse-grained
limit, the linear term of the Kardar-Parisi-Zhang equation dominates in short
times (low-roughness) and, in asymptotic times, the nonlinear term prevails.
The crossover between linear and nonlinear behaviors occurs in a characteristic
time t_c which only depends on the magnitude of the parameter s, related to the
nonlinear term. In d=2, we find indications of a similar crossover, that is,
logarithmic temporal behavior of roughness in short times and power law
behavior in asymptotic times
Strong quantum memory at resonant Fermi edges revealed by shot noise
Studies of non-equilibrium current fluctuations enable assessing correlations
involved in quantum transport through nanoscale conductors. They provide
additional information to the mean current on charge statistics and the
presence of coherence, dissipation, disorder, or entanglement. Shot noise,
being a temporal integral of the current autocorrelation function, reveals
dynamical information. In particular, it detects presence of non-Markovian
dynamics, i.e., memory, within open systems, which has been subject of many
current theoretical studies. We report on low-temperature shot noise
measurements of electronic transport through InAs quantum dots in the
Fermi-edge singularity regime and show that it exhibits strong memory effects
caused by quantum correlations between the dot and fermionic reservoirs. Our
work, apart from addressing noise in archetypical strongly correlated system of
prime interest, discloses generic quantum dynamical mechanism occurring at
interacting resonant Fermi edges.Comment: 6 pages, 3 figure
Predictability of evolutionary trajectories in fitness landscapes
Experimental studies on enzyme evolution show that only a small fraction of
all possible mutation trajectories are accessible to evolution. However, these
experiments deal with individual enzymes and explore a tiny part of the fitness
landscape. We report an exhaustive analysis of fitness landscapes constructed
with an off-lattice model of protein folding where fitness is equated with
robustness to misfolding. This model mimics the essential features of the
interactions between amino acids, is consistent with the key paradigms of
protein folding and reproduces the universal distribution of evolutionary rates
among orthologous proteins. We introduce mean path divergence as a quantitative
measure of the degree to which the starting and ending points determine the
path of evolution in fitness landscapes. Global measures of landscape roughness
are good predictors of path divergence in all studied landscapes: the mean path
divergence is greater in smooth landscapes than in rough ones. The
model-derived and experimental landscapes are significantly smoother than
random landscapes and resemble additive landscapes perturbed with moderate
amounts of noise; thus, these landscapes are substantially robust to mutation.
The model landscapes show a deficit of suboptimal peaks even compared with
noisy additive landscapes with similar overall roughness. We suggest that
smoothness and the substantial deficit of peaks in the fitness landscapes of
protein evolution are fundamental consequences of the physics of protein
folding.Comment: 14 pages, 7 figure
Direct electronic measurement of the spin Hall effect
The generation, manipulation and detection of spin-polarized electrons in
nanostructures define the main challenges of spin-based electronics[1]. Amongst
the different approaches for spin generation and manipulation, spin-orbit
coupling, which couples the spin of an electron to its momentum, is attracting
considerable interest. In a spin-orbit-coupled system, a nonzero spin-current
is predicted in a direction perpendicular to the applied electric field, giving
rise to a "spin Hall effect"[2-4]. Consistent with this effect,
electrically-induced spin polarization was recently detected by optical
techniques at the edges of a semiconductor channel[5] and in two-dimensional
electron gases in semiconductor heterostructures[6,7]. Here we report
electrical measurements of the spin-Hall effect in a diffusive metallic
conductor, using a ferromagnetic electrode in combination with a tunnel barrier
to inject a spin-polarized current. In our devices, we observe an induced
voltage that results exclusively from the conversion of the injected spin
current into charge imbalance through the spin Hall effect. Such a voltage is
proportional to the component of the injected spins that is perpendicular to
the plane defined by the spin current direction and the voltage probes. These
experiments reveal opportunities for efficient spin detection without the need
for magnetic materials, which could lead to useful spintronics devices that
integrate information processing and data storage.Comment: 5 pages, 4 figures. Accepted for publication in Nature (pending
format approval
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