996 research outputs found
Quasideterministic generation of maximally entangled states of two mesoscopic atomic ensembles by adiabatic quantum feedback
We introduce an efficient, quasideterministic scheme to generate maximally
entangled states of two atomic ensembles. The scheme is based on quantum
nondemolition measurements of total atomic populations and on adiabatic quantum
feedback conditioned by the measurements outputs. The high efficiency of the
scheme is tested and confirmed numerically for ideal photodetection as well as
in the presence of losses.Comment: 7 pages, 6 figures, title changed, revised version published on Phys.
Rev
Unification of gravity, gauge fields, and Higgs bosons
We consider a diffeomorphism invariant theory of a gauge field valued in a
Lie algebra that breaks spontaneously to the direct sum of the spacetime
Lorentz algebra, a Yang-Mills algebra, and their complement. Beginning with a
fully gauge invariant action -- an extension of the Plebanski action for
general relativity -- we recover the action for gravity, Yang-Mills, and Higgs
fields. The low-energy coupling constants, obtained after symmetry breaking,
are all functions of the single parameter present in the initial action and the
vacuum expectation value of the Higgs.Comment: 12 pages, no figures. v2 minor correction
The Influence of Human-Milk Substitutes Marketing on Breastfeeding Intention and Practice among Native and Immigrant Brazilians
Background: The International Code of Marketing of Breast-Milk Substitutes is a global public health policy aiming to protect breastfeeding from the influence of human-milk substitutes marketing. Brazil is one of the few countries substantially implementing it. Most countries adopted selected provisions, including Portugal. Research Aim: To explore whether Braziliansâ perspectives about breastfeeding intention and practice are influenced by human-milk substitutes marketing upon migration to Portugal. Methods: A qualitative, prospective, cross-sectional survey design was conducted in Brazil and Portugal (2018â2019). Qualitative semi-structured interviews were performed with native (n = 16) and immigrant (n = 15) Brazilians. Women aged 18 or above, mothers of 0â12 month infants, and without contraindications to breastfeed, were eligible for the study. Heterogeneity sampling was employed based on socioeconomic status and infantsâ age. Content analysis was conducted using NVivo. Results: Brazilian immigrants were more aware of the potential negative influence of human-milk substitutes marketing than natives. Sociocultural factors contributed to Brazilian immigrants being less permeable to the influence of human-milk substitutes marketing in the host country, where a less protective breastfeeding environment was perceived. Conclusions: Sociocultural factors including breastfeeding promotion strategies and a strong breastfeeding culture in the home country appear to play a protective role on breastfeeding intention and practice among Brazilians migrating to Portugal. © The Author(s) 2022.The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study is funded by FEDER funds through the Operational Programme for Competitiveness and Internationalization, and by national funding through the Foundation for Science and Technology (FCT; Portuguese Ministry of Science, Technology and Higher Education), under the scope of the project ââPerinatal Health in Migrants: Barriers, Incentives and Outcomesââ (POCI-01-0145-FEDER-016874; PTDC/DTPSAP/6384/2014), the projects UIDB/04750/2020 e LA/P/0064/2020, the PhD grant PD/BD/128082/2016 (C. L.) co-funded by the FCT and Human Potential Operating Program of the European Social Fund (POPH/FSE Program) and the contract DL57/2016/CP1336/CT0001 (C.F.). A. M. has a research scholarship from the Brazilian National Council for Scientific and Technological Development (CNPq)
Which solar neutrino data favour the LMA solution?
Assuming neutrino oscillations, global analyses of solar data find that the
LOW solution is significantly disfavoured, leaving LMA as the best solution.
But the preference for LMA rests on three weak hints: the spectrum of earth
matter effects (Super-Kamiokande sees an overall day/night asymmetry only at 1
sigma), the Cl rate (but LMA and LOW predictions are both above the measured
value), the Ga rate (newer data decrease towards the LOW predictions both in
GNO and SAGE). Only new data will tell us if LMA is the true solution.Comment: 4 pages, 2 figure
Supernova neutrino oscillations: A simple analytical approach
Analyses of observable supernova neutrino oscillation effects require the
calculation of the electron (anti)neutrino survival probability P_ee along a
given supernova matter density profile. We propose a simple analytical
prescription for P_ee, based on a double-exponential form for the crossing
probability and on the concept of maximum violation of adiabaticity. In the
case of two-flavor transitions, the prescription is shown to reproduce
accurately, in the whole neutrino oscillation parameter space, the results of
exact numerical calculations for generic (realistic or power-law) profiles. The
analytical approach is then generalized to cover three-flavor transitions with
(direct or inverse) mass spectrum hierarchy, and to incorporate Earth matter
effects. Compact analytical expressions, explicitly showing the symmetry
properties of P_ee, are provided for practical calculations.Comment: 22 pages (RevTeX) + 5 figures (PostScript
Motion and position shifts induced by the double-drift stimulus are unaffected by attentional load.
The double-drift stimulus produces a strong shift in apparent motion direction that generates large errors of perceived position. In this study, we tested the effect of attentional load on the perceptual estimates of motion direction and position for double-drift stimuli. In each trial, four objects appeared, one in each quadrant of a large screen, and they moved upward or downward on an angled trajectory. The target object whose direction or position was to be judged was either cued with a small arrow prior to object motion (low attentional load condition) or cued after the objects stopped moving and disappeared (high attentional load condition). In Experiment 1, these objects appeared 10° from the central fixation, and participants reported the perceived direction of the target's trajectory after the stimulus disappeared by adjusting the direction of an arrow at the center of the response screen. In Experiment 2, the four double-drift objects could appear between 6 ° and 14° from the central fixation, and participants reported the location of the target object after its disappearance by moving the position of a small circle on the response screen. The errors in direction and position judgments showed little effect of the attentional manipulation-similar errors were seen in both experiments whether or not the participant knew which double-drift object would be tested. This suggests that orienting endogenous attention (i.e., by only attending to one object in the precued trials) does not interact with the strength of the motion or position shifts for the double-drift stimulus
KamLAND neutrino spectra in energy and time: Indications for reactor power variations and constraints on the georeactor
The Kamioka Liquid scintillator Anti-Neutrino Detector (KamLAND) is sensitive
to the neutrino event spectrum from (mainly Japanese) nuclear reactors in both
the energy domain and the time domain. While the energy spectrum of KamLAND
events allows the determination of the neutrino oscillation parameters, the
time spectrum can be used to monitor known and unknown neutrino sources. By
using available monthly-binned data on event-by-event energies in KamLAND and
on reactor powers in Japan, we perform a likelihood analysis of the neutrino
event spectra in energy and time, and find significant indications in favor of
time variations of the known reactor sources, as compared with the hypothetical
case of constant reactor neutrino flux. We also find that the KamLAND data
place interesting upper limits on the power of a speculative nuclear reactor
operating in the Earth's core (the so-called georeactor); such limits are
strengthened by including solar neutrino constraints on the neutrino mass and
mixing parameters. Our results corroborate the standard interpretation of the
KamLAND signal as due to oscillating neutrinos from known reactor sources.Comment: 22 pages, including 9 figure
Case Report: Unusual Clinical Presentation of a Rare Cardiac Inflammatory Myofibroblastic Tumor in Children: The Differential Diagnosis With Pediatric Emergencies
Introduction: There are still no guidelines about pediatric cardiac cancers. The purpose of this work is to provide new scientific data facilitating the differential diagnosis of a rare cardiac tumor with an unusual presentation, such as the cardiac inflammatory myofibroblastic tumor (IMT). Case Presentation: A 3-year-old male child presented with several symptoms including unconsciousness, vomiting, and drowsiness. A clinical and neurological examination revealed a unilateral (right) motor delay and positive unilateral Babinski sign. Electrocardiogram (ECG) was normal. Diagnostic Assessment: The total body computed tomography (CT) scans showed hypodensity in the left temporal\u2013parietal lobe, a large hypodense area in the right frontal lobe, and a second area in the left frontal lobe were found with head CT. A magnetic resonance (MR) also noted cerebral areas of hypointensity. The echocardiographic images revealed an ovoid mass, adherent to the anterolateral papillary muscle. The histological exams, performed with hematoxylin\u2013eosin, Masson's trichrome, Alcian blue PAS, Weigert and Van-Gieson stain, allowed observing the microscopic structure of the neoplastic mass. The immunohistochemical analysis was performed through subsequent antibodies: anti-vimentin, anti-actina, anti-ALK, anti-CD8, anti-CD3, anti-CD20, anti-kappa and lambda chains, and anti CD68 antibodies. The healthcare professionals diagnosed a cardiac IMT with brain embolism. Differential Diagnosis: The ventricular localization, observed through radiological exams, required a differential diagnosis with fibroma and rhabdomyoma, the presence of brain embolism with sarcoma, and its morphology with fibroma. Neurological symptoms might be attributed to encephalitis, primitive cerebral cancer, such as astrocytoma or neuroblastoma, cerebral metastases due to any malignancy, or embolic stroke. Conclusion: New studies are encouraged to better define IMT behavior and draw up guidelines confirming the crucial role of multidisciplinary approach and treatment protocol selected on the basis of the characteristics of the tumors, in the case of this rare type of cancer
The sign of the day-night asymmetry for solar neutrinos
A qualitative understanding of the day-night asymmetry for solar neutrinos is
provided. The greater night flux in nu_e is seen to be a consequence of the
fact that the matter effect in the sun and that in the earth have the same
sign. It is shown in the adiabatic approximation for the sun that for all
values of the mixing angle theta_V between 0 and pi/2, the night flux of
neutrinos is greater than the day flux. Only for small values of theta_V where
the adiabatic approximation badly fails does the sign of the day-night
asymmetry reverse.Comment: 3 pages, 3 figures, typos corrected and references adde
Evidence for Mikheyev-Smirnov-Wolfenstein effects in solar neutrino flavor transitions
We point out that the recent data from the Sudbury Neutrino Observatory,
together with other relevant measurements from solar and reactor neutrino
experiments, convincingly show that the flavor transitions of solar neutrinos
are affected by Mikheyev-Smirnov-Wolfenstein (MSW) effects. More precisely, one
can safely reject the null hypothesis of no MSW interaction energy in matter,
despite the fact that the interaction amplitude (formally treated as a free
parameter) is still weakly constrained by the current phenomenology. Such a
constraint can be improved, however, by future data from the KamLAND
experiment. In the standard MSW case, we also perform an updated analysis of
two-family active oscillations of solar and reactor neutrinos.Comment: 8 pages + 5 figyre
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