3,483 research outputs found
Hybrid Entanglement for Quantum Information and Communication Applications
Combining the multiple degrees of freedom of photons has become topical in quantum communication and information processes. This provides advantages such as increasing the amount of information that is be packed into a photon or probing the wave-particle nature of light through path-polarisation entanglement. Here we present two experiments that show the advantages of using hybrid entanglement between orbital angular moment (OAM) and polarisation. Firstly, we present results where high dimensional quantum key distribution is demonstrated with spatial modes that have non-separable polarisation-OAM DOF called vector modes. Secondly, we show that through OAM-polarisation entanglement, the traditional which-way experiment can be performed without using the traditional physical path interference approach
A non-separability measure for spatially disjoint vectorial fields
Vectorial forms of structured light that are non-separable in their spatial and polarisation degrees of freedom have become topical of late, with an extensive toolkit for their creation and control. In contrast, the toolkit for quantifying their non-separability, the inhomogeneity of the polarisation structure, is less developed and in some cases fails altogether. To overcome this, here we introduce a new measure for vectorial light, which we demonstrate both theoretically and experimentally. We consider the general case where the local polarisation homogeneity can vary spatially across the field, from scalar to vector, a condition that can arise naturally if the composite scalar fields are path separable during propagation, leading to spatially disjoint vectorial light. We show how the new measure correctly accounts for the local path-like separability of the individual scalar beams, which can have varying degrees of disjointness, even though the global vectorial field remains intact. Our work attempts to address a pressing issue in the analysis of such complex light fields, and raises important questions on spatial coherence in the context of vectorially polarised light
Quantum-Key Distribution With Vector Modes
High-dimensional encoding using higher degrees of freedom has become topical in quantum communication protocols. When taking advantage of entanglement correlations, the state space can be made even larger. Here, we exploit the entanglement between two dimensional space and polarization qubits, to realize a four-dimensional quantum key distribution protocol. This is achieved by using entangled states as a basis, analogous to the Bell basis, rather than typically encoding information on individual qubits. The encoding and decoding in the required complementary bases is achieved by manipulating the Pancharatnam-Berry phase with a single optical element: a q-plate. Our scheme shows a transmission fidelity of 0.98 and secret key rate of 0.9 bits per photon. While the use of only static elements is preferable, we show that the low secret key rate is a consequence of the filter based detection of the modes, rather than our choice of encoding modes
Are congenital malformations more frequent in fetuses with intrahepatic persistent right umbilical vein? A comparative study
Objective Persistent right umbilical vein (PRUV) is a vascular anomaly where the right umbilical vein remains as the only conduit that returns oxygenated blood to the fetus. It has classically been described as associated with numerous defects. We distinguish the intrahepatic variant (better prognosis) and the extrahepatic variant (associated with worse prognosis). The objective of this study was to compare rates of congenital malformations in fetuses with intrahepatic PRUV (I-PRUV) versus singleton pregnancies without risk factors. Materials and Methods A multicenter, crossover design, comparative study was performed between 2003 and 2013 on fetuses diagnosed with I-PRUV (n = 56), and singleton pregnancies without congenital malformation risk factors (n = 4050). Results Fifty-six cases of I-PRUV were diagnosed (incidence 1:770). A statistically significant association between I-PRUV and the presence of congenital malformations (odds ratio 4.321; 95% confidence interval 2.15â8.69) was found. This positive association was only observed with genitourinary malformations (odds ratio 3.038; 95% confidence interval 1.08â8.56). Conclusion Our rate of malformations associated with I-PRUV (17.9%) is similar to previously published rates. I-PRUV has shown a significant increase in the rate of associated malformations, although this association has only been found to be statistically significant in the genitourinary system. Noteworthy is the fact that this comparative study has not pointed to a significant increase in the congenital heart malformation rate. Diagnosis of isolated I-PRUV does not carry a worse prognosis
Cost-Utility of Mindfulness-Based Stress Reduction for Fibromyalgia versus a Multicomponent Intervention and Usual Care: A 12-Month Randomized Controlled Trial (EUDAIMON Study)
Fibromyalgia (FM) is a prevalent, chronic, disabling, pain syndrome that implies high healthcare costs. Economic evaluations of potentially effective treatments for FM are needed. The aim of this study was to analyze the cost-utility of Mindfulness-Based Stress Reduction (MBSR) as an add-on to treatment-as-usual (TAU) for patients with FM compared to an adjuvant multicomponent intervention (FibroQoL) and to TAU. We performed an economic evaluation alongside a 12 month, randomized, controlled trial; data from 204 (68 per study arm) of the 225 patients (90.1%) were included in the cost-utility analyses, which were conducted both under the government and the public healthcare system perspectives. The main outcome measures were the EuroQol (EQ-5D-5L) for assessing Quality-Adjusted Life Years (QALYs) and improvements in health-related quality of life, and the Client Service Receipt Inventory (CSRI) for estimating direct and indirect costs. Incremental cost-effectiveness ratios (ICERs) were also calculated. Two sensitivity analyses (intention-to-treat, ITT, and per protocol, PPA) were conducted. The results indicated that MBSR achieved a significant reduction in costs compared to the other study arms (p < 0.05 in the completers sample), especially in terms of indirect costs and primary healthcare services. It also produced a significant incremental effect compared to TAU in the ITT sample (Delta QALYs = 0.053, p < 0.05, where QALYs represents quality-adjusted life years). Overall, our findings support the efficiency of MBSR over FibroQoL and TAU specifically within a Spanish public healthcare context
Orthogonal U(1)'s, Proton Stability and Extra Dimensions
In models with a low quantum gravity scale, one might expect that all
operators consistent with gauge symmetries are present in the low-energy
effective theory. If this is the case, some mechanism must be present to
adequately suppress operators that violate baryon number. Here we explore the
possibility that the desired suppression is a consequence of an additional,
spontaneously-broken, non-anomalous U(1) symmetry that is orthogonal to
hypercharge. We show that successful models can be constructed in which the
additional particle content necessary to cancel anomalies is minimal, and
compatible with the constraints from precision electroweak measurements and
gauge unification. If unification is sacrificed, and only the new U(1) and its
associated Higgs fields live in the bulk, it is possible that the gauge field
zero mode and first few Kaluza-Klein excitations lie within the kinematic reach
of the Tevatron. For gauge couplings not much smaller than that of hypercharge,
we show that these highly leptophobic states could evade detection at Run I,
but be discovered at Run II. Our scenario presents an alternative to the
`cartographic' solution to baryon number violation in which leptons and quarks
are separated in an extra dimension.Comment: 16 pages LaTeX, 4 figure
Effect of tannins from tropical plants on methane production from ruminants: A systematic review
Methane (CH4) is a greenhouse gas generated during the feed fermentation processes in the rumen. However, numerous studies have been conducted to determine the capacity of plant secondary metabolites to enhance ruminal fermentation and decrease CH4 production, especially those plants rich in tannins. This review conducted a descriptive analysis and meta-analysis of the use of tannin-rich plants in tropical regions to mitigate CH4 production from livestock. The aim of this study was to analyse the effect of tannins supplementation in tropical plants on CH4 production in ruminants using a meta-analytic approach and the effect on microbial population. Sources of heterogeneity were explored using a meta-regression analysis. Final database was integrated by a total of 14 trials. The âmetaâ package in R statistical software was used to conduct the meta-analyses. The covariates defined a priori in the current meta-regression were inclusion level, species (sheep, beef cattle, dairy cattle, and cross-bred heifers) and plant. Results showed that supplementation with tropical plants with tannin contents have the greatest effects on CH4 mitigation. A negative relationship was observed between the level of inclusion and CH4 emission (â0.09), which means that the effect of CH4 mitigation is increasing as the level of tannin inclusion is higher. Therefore, less CH4 production will be obtained when supplementing tropical plants in the diet with a high dose of tannins
Characterization of the paracrine effects of human skeletal myoblasts transplanted in infarcted myocardium
The discrepancy between the functional improvements yielded experimentally by skeletal myoblasts (SM) transplanted in
infarcted myocardium and the paucity of their long-term engraftment has raised the hypothesis of cell-mediated paracrine mechanisms.
Methods and results: We analyzed gene expression and growth factors released by undifferentiated human SM (CD56+), myotubes (SM
cultured until confluence) and fibroblasts-like cells (CD56â). Gene expression revealed up-regulation of pro-angiogenic (PGF), antiapoptotics
(BAG-1, BCL-2), heart development (TNNT2, TNNC1) and extracellular matrix remodelling (MMP-2, MMP-7) genes in SM. In
line with the gene expression profile, the analysis of culture supernatants of SM by ELISA identified the release of growth factors involved in
angiogenesis (VEGF, PIGF, angiogenin, angiopoietin, HGF and PDGF-BB) as well as proteases involved in matrix remodelling (MMP2,
MMP9 and MMP10) and their inhibitors (TIMPs). Culture of smooth muscle cells (SMC), cardiomyocytes (HL-1) and human umbilical vein
endothelial cells (HUVECs) with SM-released conditioned media demonstrated an increased proliferation of HUVEC, SMC and
cardiomyocytes (pb0.05) and a decrease in apoptosis of cardiomyocytes (pb0.05). Analysis of nude rats transplanted with human SM
demonstrated expression of human-specific MMP-2, TNNI3, CNN3, PGF, TNNT2, PAX7, TGF-ÎČ, and IGF-1 1 month after transplant.
Conclusions: Our data support the paracrine hypothesis whereby myoblast-secreted factors may contribute to the beneficial effects of
myogenic cell transplantation in infarcted myocardium.
© 2008 European Society of Cardiology. Published by Elsevie
An A4 flavor model for quarks and leptons in warped geometry
We propose a spontaneous A4 flavor symmetry breaking scheme implemented in a
warped extra dimensional setup to explain the observed pattern of quark and
lepton masses and mixings. The main advantages of this choice are the
explanation of fermion mass hierarchies by wave function overlaps, the
emergence of tribimaximal neutrino mixing and zero quark mixing at the leading
order and the absence of tree-level gauge mediated flavor violations. Quark
mixing is induced by the presence of bulk flavons, which allow for cross-brane
interactions and a cross-talk between the quark and neutrino sectors, realizing
the spontaneous symmetry breaking pattern A4 --> nothing first proposed in
[X.G.\,He, Y.Y.\,Keum, R.R.\,Volkas, JHEP{0604}, 039 (2006)]. We show that the
observed quark mixing pattern can be explained in a rather economical way,
including the CP violating phase, with leading order cross-interactions, while
the observed difference between the smallest CKM entries V_{ub} and V_{td} must
arise from higher order corrections. We briefly discuss bounds on the
Kaluza-Klein scale implied by flavor changing neutral current processes in our
model and show that the residual little CP problem is milder than in flavor
anarchic models.Comment: 34 pages, 2 figures; version published in JHE
Genetic variation of cork oak a tool for improving regeneration of cork oak woodlands
The European Academies' Science Advisory Council (2017) reports that the Mediterranean forest
is already being affected by climate change (IPCC, 2014) and cork oak woodlands are particularly vulnerable
to high-end climate scenarios that go above the Paris Agreement 2° C increase in temperature. Since longer,
more frequent, and more intense drought periods are expected, stress caused by the expansion of arid and
semi-arid climate will affect the species distribution. Consequently, not only established stands may be prone
to tree mortality, but also the current reforestation effort may be jeopardized by low survival rates attributed
to the use of unsuitable genetic material.
It is expected that, through genetic adaptation and/or phenotypic plasticity, cork oak populations may have
developed significant differences in fitness and the traits related to it. In this context, provenance and
progeny trials are the best resource of material to assess the variability between and within populations from
seed sources sampled in a wide range of locations (stands) covering the geographical distribution of the
species. Profiting from the multi-locality provenance and progeny trials belonging to a Network, established
in 1998, in the initiative frame of FAIR I CT 0202 for the evaluation of genetic resources of cork oak for
appropriate use in breeding and gene conservation strategiesâ, where 35 cork oak populations covering all
the natural distribution area are represented. The provenance trials that where set up in different countries
are entering now the age of first debarking and this should allow to have first data about the influence of
genetics on production by different site qualities. INCREDIBLE project should document this knowledgeFAIR I CT 0202info:eu-repo/semantics/publishedVersio
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