96 research outputs found
Beyond Rankings: Exploring the Impact of SERP Features on Organic Click-through Rates
Search Engine Result Pages (SERPs) serve as the digital gateways to the vast
expanse of the internet. Past decades have witnessed a surge in research
primarily centered on the influence of website ranking on these pages, to
determine the click-through rate (CTR). However, during this period, the
landscape of SERPs has undergone a dramatic evolution: SERP features,
encompassing elements such as knowledge panels, media galleries, FAQs, and
more, have emerged as an increasingly prominent facet of these result pages.
Our study examines the crucial role of these features, revealing them to be not
merely aesthetic components, but strongly influence CTR and the associated
behavior of internet users. We demonstrate how these features can significantly
modulate web traffic, either amplifying or attenuating it. We dissect these
intricate interaction effects leveraging a unique dataset of 67,000 keywords
and their respective Google SERPs, spanning over 40 distinct US-based
e-commerce domains, generating over 6 million clicks from 24 million views.
This cross-website dataset, unprecedented in its scope, enables us to assess
the impact of 24 different SERP features on organic CTR. Through an ablation
study modeling CTR, we illustrate the incremental predictive power these
features hold.Comment: submitted IEEE DSAA conference, 14 pages, 5 figures, 2 table
Phases of massive scalar field collapse
We study critical behavior in the collapse of massive spherically symmetric
scalar fields. We observe two distinct types of phase transition at the
threshold of black hole formation. Type II phase transitions occur when the
radial extent of the initial pulse is less than the Compton
wavelength () of the scalar field. The critical solution is that
found by Choptuik in the collapse of massless scalar fields. Type I phase
transitions, where the black hole formation turns on at finite mass, occur when
. The critical solutions are unstable soliton stars with
masses \alt 0.6 \mu^{-1}. Our results in combination with those obtained for
the collapse of a Yang-Mills field~{[M.~W. Choptuik, T. Chmaj, and P. Bizon,
Phys. Rev. Lett. 77, 424 (1996)]} suggest that unstable, confined solutions to
the Einstein-matter equations may be relevant to the critical point of other
matter models.Comment: 5 pages, RevTex, 4 postscript figures included using psfi
Lack of Immediate Effects on Excitation and Interhemispheric Inhibition of the Human Motor Cortex
Transcranial alternating current stimulation (tACS) is a form of noninvasive
brain stimulation and is capable of influencing brain oscillations and
cortical networks. In humans, the endogenous oscillation frequency in
sensorimotor areas peaks at 20 Hz. This beta-band typically occurs during
maintenance of tonic motor output and seems to play a role in interhemispheric
coordination of movements. Previous studies showed that tACS applied in
specific frequency bands over primary motor cortex (M1) or the visual cortex
modulates cortical excitability within the stimulated hemisphere. However, the
particular impact remains controversial because effects of tACS were shown to
be frequency, duration and location specific. Furthermore, the potential of
tACS to modulate cortical interhemispheric processing, like interhemispheric
inhibition (IHI), remains elusive. Transcranial magnetic stimulation (TMS) is
a noninvasive and well-tolerated method of directly activating neurons in
superficial areas of the human brain and thereby a useful tool for evaluating
the functional state of motor pathways. The aim of the present study was to
elucidate the immediate effect of 10 min tACS in the ÎČ-frequency band (20 Hz)
over left M1 on IHI between M1s in 19 young, healthy, right-handed
participants. A series of TMS measurements (motor evoked potential (MEP) size,
resting motor threshold (RMT), IHI from left to right M1 and vice versa) was
performed before and immediately after tACS or sham using a double-blinded,
cross-over design. We did not find any significant tACS-induced modulations of
intracortical excitation (as assessed by MEP size and RMT) and/or IHI. These
results indicate that 10 min of 20 Hz tACS over left M1 seems incapable of
modulating immediate brain activity or inhibition. Further studies are needed
to elucidate potential aftereffects of 20 Hz tACS as well as frequency-
specific effects of tACS on intracortical excitation and IHI
Anodal Transcranial Direct Current Stimulation Does Not Facilitate Dynamic Balance Task Learning in Healthy Old Adults
Older adults frequently experience a decrease in balance control that leads to
increased numbers of falls, injuries and hospitalization. Therefore,
evaluating older adultsâ ability to maintain balance and examining new
approaches to counteract age-related decline in balance control is of great
importance for fall prevention and healthy aging. Non-invasive brain
stimulation techniques such as transcranial direct current stimulation (tDCS)
have been shown to beneficially influence motor behavior and motor learning.
In the present study, we investigated the influence of tDCS applied over the
leg area of the primary motor cortex (M1) on balance task learning of healthy
elderly in a dynamic balance task (DBT). In total, 30 older adults were
enrolled in a cross-sectional, randomized design including two consecutive DBT
training sessions. Only during the first DBT session, either 20 min of anodal
tDCS (a-tDCS) or sham tDCS (s-tDCS) were applied and learning improvement was
compared between the two groups. Our data showed that both groups successfully
learned to perform the DBT on both training sessions. Interestingly, between-
group analyses revealed no difference between the a-tDCS and the s-tDCS group
regarding their level of task learning. These results indicate that the
concurrent application of tDCS over M1 leg area did not elicit DBT learning
enhancement in our study cohort. However, a regression analysis revealed that
DBT performance can be predicted by the kinematic profile of the movement, a
finding that may provide new insights for individualized approaches of
treating balance and gait disorders
Non-linear instability of Kerr-type Cauchy horizons
Using the general solution to the Einstein equations on intersecting null
surfaces developed by Hayward, we investigate the non-linear instability of the
Cauchy horizon inside a realistic black hole. Making a minimal assumption about
the free gravitational data allows us to solve the field equations along a null
surface crossing the Cauchy Horizon. As in the spherical case, the results
indicate that a diverging influx of gravitational energy, in concert with an
outflux across the CH, is responsible for the singularity. The spacetime is
asymptotically Petrov type N, the same algebraic type as a gravitational shock
wave. Implications for the continuation of spacetime through the singularity
are briefly discussed.Comment: 11 pages RevTeX, two postscript figures included using epsf.st
Quantum corrections to critical phenomena in gravitational collapse
We investigate conformally coupled quantum matter fields on spherically
symmetric, continuously self-similar backgrounds. By exploiting the symmetry
associated with the self-similarity the general structure of the renormalized
quantum stress-energy tensor can be derived. As an immediate application we
consider a combination of classical, and quantum perturbations about exactly
critical collapse. Generalizing the standard argument which explains the
scaling law for black hole mass, , we
demonstrate the existence of a quantum mass gap when the classical critical
exponent satisfies . When our argument is
inconclusive; the semi-classical approximation breaks down in the spacetime
region of interest.Comment: RevTeX, 6 pages, 3 figures included using psfi
- âŠ