1,738 research outputs found
Objectivity (or lack thereof): Comparison between predictions of quantum Darwinism and spectrum broadcast structure
Quantum Darwinism and spectrum broadcast structure describe the emergence of objectivity in quantum
systems. However, it is unclear whether these two frameworks lead to consistent predictions on the objectivity
of the state of a quantum system in a given scenario. In this paper, we jointly investigate quantum Darwinism
and spectrum broadcasting, as well as the subdivision of quantum Darwinism into accessible information and
quantum discord, in a two-level system interacting with an N-level environment via a random matrix coupling.
We propose a partial trace method to suitably and consistently partition the effective N-level environment and
compare the predictions with those obtained using the partitioning method proposed by Perez [Phys. Rev.
A 81, 052326 (2010)]. We find that quantum Darwinism can apparently emerge under the Perez trace even
when spectrum broadcast structure does not emerge, and the majority of the quantum mutual information
between system and environment fractions is in fact quantum in nature. This work therefore shows there can
be discrepancies between quantum Darwinism and the nature of information and spectrum broadcast structure
Strong Quantum Darwinism and Strong Independence are Equivalent to Spectrum Broadcast Structure
How the objective everyday world emerges from the underlying quantum behavior of its microscopic constituents is an open question at the heart of the foundations of quantum mechanics. Quantum Darwinism and spectrum broadcast structure are two different frameworks providing key insight into this question. Recent works, however, indicate these two frameworks can lead to conflicting predictions on the objectivity of the state of a system interacting with an environment. Here, we provide a resolution to this issue by defining strong quantum Darwinism and proving that it is equivalent to spectrum broadcast structure when combined with strong independence of the subenvironments. We further show that strong quantum Darwinism is sufficient and necessary to signal state objectivity without the requirement of strong independence. Our Letter unveils the deep connection between strong quantum Darwinism and spectrum broadcast structure, thereby making fundamental progress toward understanding and solving the emergence of classicality from the quantum world. Together they provide us a sharper understanding of the transition in terms of state structure, geometry, and quantum and classical information
Microabrasion in tooth enamel discoloration defects: three cases with long-term follow-ups
Superficial irregularities and certain intrinsic stains on the dental enamel surfaces can be resolved by enamel microabrasion, however, treatment for such defects need to be confined to the outermost regions of the enamel surface. Dental bleaching and resin-based composite repair are also often useful for certain situations for tooth color corrections. This article presented and discussed the indications and limitations of enamel microabrasion treatment. Three case reports treated by enamel microabrasion were also presented after 11, 20 and 23 years of follow-ups
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Investigating the impact of poverty on colonization and infection with drug-resistant organisms in humans: a systematic review
Background
Poverty increases the risk of contracting infectious diseases and therefore exposure to antibiotics. Yet there is lacking evidence on the relationship between income and non-income dimensions of poverty and antimicrobial resistance. Investigating such relationship would strengthen antimicrobial stewardship interventions.
Methods
A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Ovid, MEDLINE, EMBASE, Scopus, CINAHL, PsychINFO, EBSCO, HMIC, and Web of Science databases were searched in October 2016. Prospective and retrospective studies reporting on income or non-income dimensions of poverty and their influence on colonisation or infection with antimicrobial-resistant organisms were retrieved. Study quality was assessed with the Integrated quality criteria for review of multiple study designs (ICROMS) tool.
Results
Nineteen articles were reviewed. Crowding and homelessness were associated with antimicrobial resistance in community and hospital patients. In high-income countries, low income was associated with Streptococcus pneumoniae and Acinetobacter baumannii resistance and a seven-fold higher infection rate. In low-income countries the findings on this relation were contradictory. Lack of education was linked to resistant S. pneumoniae and Escherichia coli. Two papers explored the relation between water and sanitation and antimicrobial resistance in low-income settings.
Conclusions
Despite methodological limitations, the results suggest that addressing social determinants of poverty worldwide remains a crucial yet neglected step towards preventing antimicrobial resistance
Severe axial vertebral rotation treated with a modified Boston brace: a case report
We report the case of a 13-year-old Caucasian girl suffering from severe axial rotation of the T5 to L4 vertebrae. The patient (initially examined during a school screening study) was at first considered to be suspicious of suffering from scoliosis due to a highly positive Adam's forward bending test. However, her radiographic evaluation revealed the existence of axial rotation in 12 of her vertebrae, without inclination in the sagittal and coronal planes. After an observation period of 12 months and due to the fact that both her physical appearance and the measured vertebral rotation deteriorated, the patient was given a modified thoracolumbar Boston brace that had an immediate positive derotational effect on all but two vertebrae. Twenty four months later, the progress of the vertebral rotation(s) seems to have been halted and most affected vertebrae appear to be stabilized in their new, 'post-brace', reduced position, with better results shown when the Boston brace is worn. The patient remains under constant medical observation. The application of a modified Boston brace seems to have served well (so far) a useful purpose for reducing and stabilizing this case of severe axial vertebral rotation, providing less deformity and (possibly) offering a better final cosmetic result
Flavor violating leptonic decays of τ and μ leptons in the Standard Model with massive neutrinos
We have revisited the computations of the flavor
violating leptonic decays of the τ and μ leptons into three
lighter charged leptons in the Standard Model with massive
neutrinos. We were driven by a claimed unnaturally large
branching ratio predicted for the τ
− → μ
−
l
+
l
− (l = μ, e)
decays (Pham, Eur Phys J C 8:513 1999), which was at odds
with the corresponding predictions for the μ
− → e−e−e+
processes (Petcov, Sov J Nucl Phys 25:340 1977). In contrast
with the prediction in [17], our results are strongly suppressed
and in good agreement with the approximationmade
in Ref. [15], where masses and momenta of the external particles
were neglected in order to deal with the loop integrals.
However -as a result of keeping external momenta and
masses in the computation of the dominant penguin and box
diagrams- we even find slightly smaller branching fractions.
Therefore, we confirm that any future observation of such
processes would be an unambiguous manifestation of new
physics beyond the Standard Model.Finally, we also
acknowledge support from Conacyt through projects FOINS-296-2016
(Fronteras de la Ciencia), and 236394 and 250628 (Ciencia Básica)
HPV genotypes in the oral cavity/oropharynx of children and adolescents: cross-sectional survey in Poland
Human papillomaviruses (HPVs) are a very complex group of pathogenic viruses, with more than 80 types, causing human infection. Given the prevalence of HPV infection and its relationship with the development of cervical and many other cancers, HPV vaccine development has been a major public health initiative worldwide in the last decade. The aim of the presented study was to identify HPV DNA by MY-PCR in 4,150 school children and adolescents, aged 10–18 years in the Wielkopolska region, Poland. All individuals were asked to fill in extensive questionnaires; further normal, oral squamous cells were collected from each pupil. Cellular DNA was isolated and used as a MY-PCR template to estimate the incidence of HPV-active infection. Forty five subjects (1.08% of the sample) were carriers of oropharyngeal HPVs. HPV status and variables of interest, such as age, gender, socioeconomical status, and risk factors (smoking and sexual intercourse history, alcohol consumption) were not correlated. The presence of HPVs in the oral cavity was cumulated in several schools of the region. DNA sequencing of MY-PCR products revealed only four HPV genotypes. The most frequent genotype was HPV11 (38/45 HPV-positive cases), while other more rare genotypes were HPV6 (3/45), HPV12 (3/45), and HPV57 (1/45). Conclusion: Our findings presented herein, reveal a relatively low prevalance of oropharyngeal HPVs in Polish adolescents and fill an important gap in the knowledge of oral HPV infections of children above 10 years and adolescents
Neuronal circuitry for pain processing in the dorsal horn
Neurons in the spinal dorsal horn process sensory information, which is then transmitted to several brain regions, including those responsible for pain perception. The dorsal horn provides numerous potential targets for the development of novel analgesics and is thought to undergo changes that contribute to the exaggerated pain felt after nerve injury and inflammation. Despite its obvious importance, we still know little about the neuronal circuits that process sensory information, mainly because of the heterogeneity of the various neuronal components that make up these circuits. Recent studies have begun to shed light on the neuronal organization and circuitry of this complex region
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