15,192 research outputs found
Satellite observations of reconnection between emerging and pre-existing small-scale magnetic fields
We report multi-wavelength ultraviolet observations taken with the IRIS
satellite, concerning the emergence phase in the upper chromosphere and
transition region of an emerging flux region (EFR) embedded in the unipolar
plage of active region NOAA 12529. The photospheric configuration of the EFR is
analyzed in detail benefitting from measurements taken with the
spectropolarimeter aboard the Hinode satellite, when the EFR was fully
developed. In addition, these data are complemented by full-disk, simultaneous
observations of the SDO satellite, relevant to the photosphere and the corona.
In the photosphere, magnetic flux emergence signatures are recognized in the
fuzzy granulation, with dark alignments between the emerging polarities,
cospatial with highly inclined fields. In the upper atmospheric layers, we
identify recurrent brightenings that resemble UV bursts, with counterparts in
all coronal passbands. These occur at the edges of the EFR and in the region of
the arch filament system (AFS) cospatial to the EFR. Jet activity is also found
at chromospheric and coronal levels, near the AFS and the observed brightness
enhancement sites. The analysis of the IRIS line profiles reveals the heating
of dense plasma in the low solar atmosphere and the driving of bi-directional
high-velocity flows with speeds up to 100 km/s at the same locations.
Furthermore, we detect a correlation between the Doppler velocity and line
width of the Si IV 1394 and 1402 \AA{} line profiles in the UV burst pixels and
their skewness. Comparing these findings with previous observations and
numerical models, we suggest evidence of several long-lasting, small-scale
magnetic reconnection episodes between the emerging bipole and the ambient
field. This process leads to the cancellation of a pre-existing photospheric
flux concentration of the plage with the opposite polarity flux patch of the
EFR. [...]Comment: 4 pages, 2 figures, to be published in "Nuovo Cimento C" as
proceeding of the Third Meeting of the Italian Solar and Heliospheric
Communit
The Americanization of International Litigation
Published in cooperation with the American Bar Association Section of Dispute Resolutio
2D-3D registration of CT vertebra volume to fluoroscopy projection: A calibration model assessment (doi:10.1155/2010/806094)
This study extends a previous research concerning intervertebral motion registration by means of 2D dynamic fluoroscopy to obtain a more comprehensive 3D description of vertebral kinematics. The problem of estimating the 3D rigid pose of a CT volume of a vertebra from its 2D X-ray fluoroscopy projection is addressed. 2D-3D registration is obtained maximising a measure of similarity between Digitally Reconstructed Radiographs (obtained from the CT volume) and real fluoroscopic projection. X-ray energy correction was performed. To assess the method a calibration model was realised a sheep dry vertebra was rigidly fixed to a frame of reference including metallic markers. Accurate measurement of 3D orientation was obtained via single-camera calibration of the markers and held as true 3D vertebra position; then, vertebra 3D pose was estimated and results compared. Error analysis revealed accuracy of the order of 0.1 degree for the rotation angles of about 1?mm for displacements parallel to the fluoroscopic plane, and of order of 10?mm for the orthogonal displacement.<br/
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Improving Visual Field Examination of the Macula Using Structural Information
Purpose: To investigate a novel approach for structure-function modeling in glaucoma to improve visual field testing in the macula.
Methods: We acquired data from the macular region in 20 healthy eyes and 31 with central glaucomatous damage. Optical coherence tomography (OCT) scans were used to estimate the local macular ganglion cell density. Perimetry was performed with a fundus-tracking device using a 10-2 grid. OCT scans were matched to the retinal image from the fundus perimeter to accurately map the tested locations onto the structural damage. Binary responses from the subjects to all presented stimuli were used to calculate the structure-function model used to generate prior distributions for a ZEST (Zippy Estimation by Sequential Testing) Bayesian strategy. We used simulations based on structural and functional data acquired from an independent dataset of 20 glaucoma patients to compare the performance of this new strategy, structural macular ZEST (MacS-ZEST), with a standard ZEST.
Results: Compared to the standard ZEST, MacS-ZEST reduced the number of presentations by 13% in reliable simulated subjects and 14% with higher rates (≥20%) of false positive or false negative errors. Reduction in mean absolute error was not present for reliable subjects but was gradually more important with unreliable responses (≥10% at 30% error rate).
Conclusions: Binary responses can be modeled to incorporate detailed structural information from macular OCT into visual field testing, improving overall speed and accuracy in poor responders.
Translational Relevance: Structural information can improve speed and reliability for macular testing in glaucoma practice
Assessing the impact of seasonal-rainfall anomalies on catchment-scale water balance components
Abstract. Although water balance components at the catchment scale
are strongly related to annual rainfall, the availability of water resources in
Mediterranean catchments also depends on rainfall seasonality. Observed
seasonal anomalies in historical records are fairly episodic, but an
increase in their frequency might exacerbate water deficit or water excess
if the rainy season shortens or extends its duration, e.g., due to climate
change. This study evaluates the sensitivity of water yield,
evapotranspiration, and groundwater recharge to changes in rainfall
seasonality by using the Soil Water Assessment Tool (SWAT) model applied to
the upper Alento River catchment (UARC) in southern Italy, where a long time
series of daily rainfall is available from 1920 to 2018. We compare two
distinct approaches: (i) a "static" approach, where three seasonal features
(namely rainy, dry, and transition fixed-duration 4-month seasons) are
identified through the standardized precipitation index (SPI) and (ii) a
"dynamic" approach based on a stochastic framework, where the duration of
two seasons (rainy and dry seasons) varies from year to year according to a
probability distribution. Seasonal anomalies occur when the transition
season is replaced by the rainy or dry season in the first approach and when
season duration occurs in the tails of its normal distribution in the second
approach. Results are presented within a probabilistic framework. We also
show that the Budyko curve is sensitive to the rainfall seasonality regime
in UARC by questioning the implicit assumption of a temporal steady state
between annual average dryness and the evaporative index. Although the
duration of the rainy season does not exert a major control on water
balance, we were able to identify season-dependent regression equations
linking water yield to the dryness index in the rainy season
Spin-orbital coupling in a triplet superconductor-ferromagnet junction
We study a novel type of coupling between spin and orbital degrees of freedom
which appears at triplet superconductor-ferromagnet interfaces. Using a
self-consistent spatially-dependent mean-field theory, we show that increasing
the angle between the ferromagnetic moment and the triplet vector order
parameter enhances or suppresses the p-wave gap close to the interface,
according as the gap antinodes are parallel or perpendicular to the boundary,
respectively. The associated change in condensation energy establishes an
orbitally-dependent preferred orientation for the magnetization. When both gap
components are present, as in a chiral superconductor, we observe a first-order
transition between different moment orientations as a function of the exchange
field strength.Comment: 5 pages, 4 figures and Supplemental Material (3 pages
Influence of Cleft Lip and Palate on Oral Health-Related Quality of Life in Northern Italy: Exploring Both the Children’s and Caregivers’ Perspectives
The aim of this cross-sectional study was to examine whether parents/caregivers’ perceptions of oral health-related quality of life (OHRQoL) differ from that of their cleft children, exploring the impact of demographic variables and cleft type on their agreement. Fifty-three primary and secondary schoolchildren, with non-syndromic orofacial cleft, and their parents answered the Child Oral Health Impact Profile (COHIP) questionnaire. Concordance between caregivers’ and children’s reports was low to moderate. Parents/caregivers had worse perceptions of OHRQoL compared to that of their children, peer interaction and functional well-being domains being statistically significantly different (p = 0.033 and p = 0.005, respectively). Cleft type, gender and parents’ country of origin seemed to be potential contributing factors of disagreement. Parents overestimated the impact of unilateral (p = 0.047) and bilateral cleft lip and palate (p = 0.021) on OHRQoL, and they rated more poorly than their male children did. Italian parents were more concerned about the functional well-being of their children (p = 0.014), and foreign parents about peer interaction (p = 0.010) and school environment (p = 0.012) dimensions. These findings suggest that parental assessment of OHRQoL cannot replace that of school-aged children, but they are complementary as they cover different, but equally relevant perspectives
Evaluation of biodentine in pulpotomies of primary teeth with different stages of root resorption using a novel composite outcome score
This study aimed to assess the success of pulpotomy in primary molars using Biodentine, new-developed tri-calcium, di-calcium-based silicate cement, at 6 and 12 months. The hypothesis was that stages of root resorption could influence the treatment success. A novel composite score was used based on five clinical and radiographic outcomes: soft-tissue pathology, pain to percussion, pathologic mobility, radiolucency and pathologic root resorption. Patients’ compliance and intraoperative pain experience were recorded using the Frankl scale and the Wong–Baker scale. A total of 22 primary molars, 9 in stage S (stability) and 13 in stage R (resorption) were submitted to pulpotomy using Biodentine and restored with composite resin. The success rate was 92.3% in the R group compared to 100% in the S group at both 6 and 12 months (p = 0.850). There was no statistically significant effect of type of molar, tooth position and type of carious lesions on the composite outcome (all p > 0.05). Overall, 73% of the children experienced no or mild/moderate pain and 77% had a cooperative attitude. Children younger than 7 years old experienced more pain (p = 0.04). Biodentine is a promising biomaterial for pulpotomy of primary teeth regardless of the stage of root resorption
Relaxation to equilibrium driven via indirect control in Markovian dynamics
We characterize to what extent it is possible to modify the stationary states
of a quantum dynamical semigroup, that describes the irreversible evolution of
a two-level system, by means of an auxiliary two-level system. We consider
systems that can be initially entangled or uncorrelated. We find that the
indirect control of the stationary states is possible, even if there are not
initial correlations, under suitable conditions on the dynamical parameters
characterizing the evolution of the joint system.Comment: revtex4, 7 page
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