11,884 research outputs found
Deep Cover HCI
The growing popularity of methodologies that turn "to the wild" for real world data creates new ethical issues for the HCI community. For investigations questioning interactions in public or transient spaces, crowd interaction, or natural behaviour, uncontrolled and uninfluenced (by the experimenter) experiences represent the ideal evaluation environment. We argue that covert research can be completed rigorously and ethically to expand our knowledge of ubiquitous technologies. Our approach, which we call Deep Cover HCI, utilises technology-supported observation in public spaces to stage completely undisturbed experiences for evaluation. We complete studies without informed consent and without intervention from an experimenter in order to gain new insights into how people use technology in public settings. We argue there is clear value in this approach, reflect on the ethical issues of such investigations, and describe our ethical guidelines for completing Deep Cover HCI Research
Contraception Options and Provision to Adolescents
Adolescent pregnancy is a significant cause of global morbidity and mortality. Adolescents who become pregnancy have lower educational attainment, are more likely to live in poverty, and have lower wellbeing. Increasing access to hormonal contraceptives and long acting reversible contraception is highly effective in reducing adolescent pregnancies. This narrative review covers key aspects of the provision of contraception to adolescents, including confidentiality, counseling, and data supporting expanded access to adolescents. We provide information for pediatric providers to start adolescent patients on contraceptives, including a detailed description of each method, including effectiveness, use, starting, side effects and benefits. Tools for counseling and prescribing are provided
Unified Description of Aging and Rate Effects in Yield of Glassy Solids
The competing effects of slow structural relaxations (aging) and deformation
at constant strain rate on the shear yield stress of simple model
glasses are examined using molecular simulations. At long times, aging leads to
a logarithmic increase in density and . The yield stress also rises
logarithmically with rate, but shows a sharp transition in slope at a rate that
decreases with increasing age. We present a simple phenomenological model that
includes both intrinsic rate dependence and the change in properties with the
total age of the system at yield. As predicted by the model, all data for each
temperature collapse onto a universal curve.Comment: 4 pages, 3 figure
An Analysis of Regulations Under the Resource Conservation and Recovery Act
This Article analyzes efforts to deal with the generation, transportation, treatment, storage and disposal of hazardous wastes under the Resource Conservation and Recovery Act and the Environmental Protection Agency\u27s regulations promulgated thereunder
Background modeling for video sequences by stacked denoising autoencoders
Nowadays, the analysis and extraction of relevant information in visual data flows is of paramount importance. These images sequences can last for hours, which implies that the model must adapt to all kinds of circumstances so that the performance of the system does not decay over time. In this paper we propose a methodology for background modeling and foreground detection, whose main characteristic is its robustness against stationary noise. Thus, stacked denoising autoencoders are applied to generate a set of robust characteristics for each region or patch of the image, which will be the input of a probabilistic model to determine if that region is background or foreground. The evaluation of a set of heterogeneous sequences results in that, although our proposal is similar to the classical methods existing in the literature, the inclusion of noise in these sequences causes drastic performance drops in the competing methods, while in our case the performance stays or falls slightly.Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech
A Barren Landscape?
We consider the generation of a non-perturbative superpotential in F-theory
compactifications with flux. We derive a necessary condition for the generation
of such a superpotential in F-theory. For models with a single volume modulus,
we show that the volume modulus is never stabilized by either abelian
instantons or gaugino condensation. We then comment on how our analysis extends
to a larger class of compactifications. From our results, it appears that among
large volume string compactifications, metastable de Sitter vacua (should any
exist) are non-generic.Comment: 14 pages, comments adde
Superlubricity - a new perspective on an established paradigm
Superlubricity is a frictionless tribological state sometimes occurring in
nanoscale material junctions. It is often associated with incommensurate
surface lattice structures appearing at the interface. Here, by using the
recently introduced registry index concept which quantifies the registry
mismatch in layered materials, we prove the existence of a direct relation
between interlayer commensurability and wearless friction in layered materials.
We show that our simple and intuitive model is able to capture, down to fine
details, the experimentally measured frictional behavior of a hexagonal
graphene flake sliding on-top of the surface of graphite. We further predict
that superlubricity is expected to occur in hexagonal boron nitride as well
with tribological characteristics very similar to those observed for the
graphitic system. The success of our method in predicting experimental results
along with its exceptional computational efficiency opens the way for modeling
large-scale material interfaces way beyond the reach of standard simulation
techniques.Comment: 18 pages, 7 figure
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Retrieval Failure Contributes to Gist-Based False Recognition
People often falsely recognize items that are similar to previously encountered items. This robust memory error is referred to as gist-based false recognition. A widely held view is that this error occurs because the details fade rapidly from our memory. Contrary to this view, an initial experiment revealed that, following the same encoding conditions that produce high rates of gist-based false recognition, participants overwhelmingly chose the correct target rather than its related foil when given the option to do so. A second experiment showed that this result is due to increased access to stored details provided by reinstatement of the originally encoded photograph, rather than to increased attention to the details. Collectively, these results suggest that details needed for accurate recognition are, to a large extent, still stored in memory and that a critical factor determining whether false recognition will occur is whether these details can be accessed during retrieval.Psycholog
Toward the End of Time
The null-brane space-time provides a simple model of a big crunch/big bang
singularity. A non-perturbative definition of M-theory on this space-time was
recently provided using matrix theory. We derive the fermion couplings for this
matrix model and study the leading quantum effects. These effects include
particle production and a time-dependent potential. Our results suggest that as
the null-brane develops a big crunch singularity, the usual notion of
space-time is replaced by an interacting gluon phase. This gluon phase appears
to constitute the end of our conventional picture of space and time.Comment: 31 pages, reference adde
Contact and Friction of Nano-Asperities: Effects of Adsorbed Monolayers
Molecular dynamics simulations are used to study contact between a rigid,
nonadhesive, spherical tip with radius of order 30nm and a flat elastic
substrate covered with a fluid monolayer of adsorbed chain molecules. Previous
studies of bare surfaces showed that the atomic scale deviations from a sphere
that are present on any tip constructed from discrete atoms lead to significant
deviations from continuum theory and dramatic variability in friction forces.
Introducing an adsorbed monolayer leads to larger deviations from continuum
theory, but decreases the variations between tips with different atomic
structure. Although the film is fluid, it remains in the contact and behaves
qualitatively like a thin elastic coating except for certain tips at high
loads. Measures of the contact area based on the moments or outer limits of the
pressure distribution and on counting contacting atoms are compared. The number
of tip atoms making contact in a time interval grows as a power of the interval
when the film is present and logarithmically with the interval for bare
surfaces. Friction is measured by displacing the tip at a constant velocity or
pulling the tip with a spring. Both static and kinetic friction rise linearly
with load at small loads. Transitions in the state of the film lead to
nonlinear behavior at large loads. The friction is less clearly correlated with
contact area than load.Comment: RevTex4, 17 pages, 13 figure
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