15,615 research outputs found
X-Raying the Dark Side of Venus - Scatter from Venus Magnetotail?
This work analyzes the X-ray, EUV and UV emission apparently coming from the
Earth-facing (dark) side of Venus as observed with Hinode/XRT and SDO/AIA
during a transit across the solar disk occurred in 2012. We have measured
significant X-Ray, EUV and UV flux from Venus dark side. As a check we have
also analyzed a Mercury transit across the solar disk, observed with Hinode/XRT
in 2006. We have used the latest version of the Hinode/XRT Point Spread
Function (PSF) to deconvolve Venus and Mercury X-ray images, in order to remove
possible instrumental scattering. Even after deconvolution, the flux from Venus
shadow remains significant while in the case of Mercury it becomes negligible.
Since stray-light contamination affects the XRT Ti-poly filter data from the
Venus transit in 2012, we performed the same analysis with XRT Al-mesh filter
data, which is not affected by the light leak. Even the Al-mesh filter data
show residual flux. We have also found significant EUV (304 A, 193 A, 335 A)
and UV (1700 A) flux in Venus shadow, as measured with SDO/AIA. The EUV
emission from Venus dark side is reduced when appropriate deconvolution methods
are applied; the emission remains significant, however. The light curves of the
average flux of the shadow in the X-ray, EUV, and UV bands appear different as
Venus crosses the solar disk, but in any of them the flux is, at any time,
approximately proportional to the average flux in a ring surrounding Venus, and
therefore proportional to the average flux of the solar regions around Venus
obscuring disk line of sight. The proportionality factor depends on the band.
This phenomenon has no clear origin; we suggest it may be due to scatter
occurring in the very long magnetotail of Venus.Comment: This paper has been accepted in The Astrophysical Journa
Hydro-Responsive Curling of the Resurrection Plant Selaginella lepidophylla
The spirally arranged stems of the spikemoss Selaginella lepidophylla, an
ancient resurrection plant, compactly curl into a nest-ball shape upon
dehydration. Due to its spiral phyllotaxy, older outer stems on the plant
interlace and envelope the younger inner stems forming the plant centre. Stem
curling is a morphological mechanism that limits photoinhibitory and thermal
damages the plant might experience in arid environments. Here, we investigate
the distinct conformational changes of outer and inner stems of S. lepidophylla
triggered by dehydration. Outer stems bend into circular rings in a relatively
short period of desiccation, whereas inner stems curl slowly into spirals due
to hydro-actuated strain gradient along their length. This arrangement eases
both the tight packing of the plant during desiccation and its fast opening
upon rehydration. The insights gained from this work shed light on the
hydro-responsive movements in plants and might contribute to the development of
deployable structures with remarkable shape transformations in response to
environmental stimuli
Development and testing of a dual accelerometer vector sensor for AUV acoustic surveys
This paper presents the design, manufacturing and testing of a Dual Accelerometer Vector Sensor (DAVS). The device was built within the activities of theWiMUST project, supported under the Horizon 2020 Framework Programme, which aims to improve the efficiency of the methodologies used to perform geophysical acoustic surveys at sea by the use of Autonomous Underwater Vehicles (AUVs). The DAVS has the potential to contribute to this aim in various ways, for example, owing to its spatial filtering capability, it may reduce the amount of post processing by discriminating the bottom from the surface reflections. Additionally, its compact size allows easier integration with AUVs and hence facilitates the vehicle manoeuvrability compared to the classical towed arrays. The present paper is focused on results related to acoustic wave azimuth estimation as an example of its spatial filtering capabilities. The DAVS device consists of two tri-axial accelerometers and one hydrophone moulded in one unit. Sensitivity and directionality of these three sensors were measured in a tank, whilst the direction estimation capabilities of the accelerometers paired with the hydrophone, forming a vector sensor, were evaluated on a Medusa Class AUV, which was sailing around a deployed sound source. Results of these measurements are presented in this paper.European Union [645141]info:eu-repo/semantics/publishedVersio
Fighting the dark side:a scoping review of dark pattern mitigation
Abstract. As technology plays an ever-greater role in the everyday life of people, during the last decade there has been a rising concern about designers using their knowledge of human behaviour to design interfaces that trick users into doing things against their best interest. These design patterns are known as dark patterns, and the human-computer interaction and design communities have condemned their use. Informed by research, lawmakers have also started to form regulations against them. This thesis aimed to first introduce what the current state of dark pattern research is, and then answer the research question of how the usage of dark patterns could be mitigated. To answer the research question, a literature review in the form of scoping review was conducted. In scoping review, 28 articles that considered dark pattern mitigation were found to be relevant to the research question. Thematic analysis was used as a qualitative analysis method to identify common themes in articles. As a result, dark pattern mitigation tactics could be divided into seven different themes: company actions and economic value, regulating dark patterns, raising public awareness, tools for users, designing for the well-being of users, educating designers and developers, and enhancing dark pattern research. Mitigation tactics or propositions were then introduced in more detail under these themes. The results of the scoping review demonstrate that there is no one specific weapon to be used in the fight against dark patterns. On the contrary, different techniques from different fields need to be used together to effectively identify and mitigate dark patterns
Search for Antimatter in Space with the Alpha Magnetic Spectrometer
The Alpha Magnetic Spectrometer (AMS) is a state of the art particle physics
experiment for the extraterrestrial study of antimatter, matter and missing
matter. AMS successfully completed the precursor STS91 Discovery flight (June
2nd-12th, 1998), completing 152 orbits at 52 degrees of latitude and about 400
km of height, collecting more than 100 million CR events. In this paper we
report on the first flight experience and we present preliminary results on the
search for nuclear antimatter. No antimatter nuclei with Z>=2 were detected. We
obtain a model dependent upper limit on the anti-He /He flux <1.14 10^^-6 In
the rigidity region between 1.6 to 20 GV we obtain a model independent,
conservative upper limit on anti-He /He flux <1.7 10^^-6 and <2.8 10^^-5 for
Z>2, improving the results of previous published searches performed with
stratospheric balloons.Comment: 1 tex file, 15 pages, 11 figures ps.gz file
Promoting Bright Patterns
User experience designers are facing increasing scrutiny and criticism for
creating harmful technologies, leading to a pushback against unethical design
practices. While clear-cut harmful practices such as dark patterns have
received attention, trends towards automation, personalization, and
recommendation present more ambiguous ethical challenges. To address potential
harm in these "gray" instances, we propose the concept of "bright patterns" -
persuasive design solutions that prioritize user goals and well-being over
their desires and business objectives. The ambition of this paper is threefold:
to define the term "bright patterns", to provide examples of such patterns, and
to advocate for the adoption of bright patterns through policymaking.Comment: For associated website, see https://brightpatterns.org/. Published to
the CHI '23 Workshop: Designing Technology and Policy Simultaneousl
Routing Physarum with electrical flow/current
Plasmodium stage of Physarum polycephalum behaves as a distributed dynamical
pattern formation mechanism who's foraging and migration is influenced by local
stimuli from a wide range of attractants and repellents. Complex protoplasmic
tube network structures are formed as a result, which serve as efficient
`circuits' by which nutrients are distributed to all parts of the organism. We
investigate whether this `bottom-up' circuit routing method may be harnessed in
a controllable manner as a possible alternative to conventional template-based
circuit design. We interfaced the plasmodium of Physarum polycephalum to the
planar surface of the spatially represented computing device, (Mills' Extended
Analog Computer, or EAC), implemented as a sheet of analog computing material
whose behaviour is input and read by a regular 5x5 array of electrodes. We
presented a pattern of current distribution to the array and found that we were
able to select the directional migration of the plasmodium growth front by
exploiting plasmodium electro-taxis towards current sinks. We utilised this
directional guidance phenomenon to route the plasmodium across its habitat and
were able to guide the migration around obstacles represented by repellent
current sources. We replicated these findings in a collective particle model of
Physarum polycephalum which suggests further methods to orient, route, confine
and release the plasmodium using spatial patterns of current sources and sinks.
These findings demonstrate proof of concept in the low-level dynamical routing
for biologically implemented circuit design
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