Descriptors of dimensionality for n × n density matrices

By using the recently introduced parametrization of an n-dimensional density matrix in terms of the indices of population asymmetry and the intrinsic coherences, we define descriptors in both integer and continuous forms of the effective dimension that take place for a complete description of a density matrix, thus providing accurate information beyond the rank of the density matrix. The concepts of dimensional folding, hidden dimensional purity, and dimensional entropy are introduced and discussed in view of the new approach presented. The results are applicable to any physical system represented by a density matrix, such as n-level quantum systems, qutrits, sets of interacting pencils of radiation, classical polarization states, and to transformations of density matrices, as occurs with quantum channels

Spin of random stationary light

We develop a theoretical foundation for the spin angular momentum (SAM) of random, statistically stationary polychromatic light fields within the framework of classical optical coherence theory. The formulation is valid for fields of arbitrary frequency bandwidth and dimensionality. Both temporal and spectral representations are given, and we further elucidate the relationship between the SAM and the polarization characteristics of such fields as compared to monochromatic light. The special cases of quasimonochromatic light and planar fields are analyzed separately. Generally, our paper offers deeper insights into the SAM and polarization structures as well as their interlinked connections in random stationary light, which could be beneficial in exploiting SAM in stochastic optical near fields and tightly focused beams exhibiting complex polarization character

Structure of polarimetric purity of three-dimensional polarization states

It has recently been demonstrated that a general three-dimensional (3D) polarization state cannot be considered an incoherent superposition of (1) a pure state, (2) a two-dimensional unpolarized state, and (3) a 3D unpolarized state [J. J. Gil, Phys. Rev. A 90, 043858 (2014)10.1103/PhysRevA.90.043858]. This fact is intimately linked to the existence of 3D polarization states with fluctuating directions of propagation, but whose associated polarization matrices R satisfy rank R=2. In this work, such peculiar states are analyzed and characterized, leading to a meaningful general classification and interpretation of 3D polarization states. Within this theoretical framework, the interrelations among the more significant polarization descriptors presented in the literature, as well as their respective physical interpretations, are studied and illustrated with examples, providing a better understanding of the structure of polarimetric purity of any kind of polarization state

Sets of orthogonal three-dimensional polarization states and their physical interpretation

The spectral and characteristic decompositions of the polarization matrix provide fruitful frameworks for the physical interpretation of three-dimensional (3D) partially polarized light fields. The decompositions are formulated in terms of the three pure eigenstates, which in turn are represented through their associated orthogonal complex 3D Jones vectors. This mathematical orthogonality does not correspond, in general, to orthogonality of the polarization-ellipse planes of the respective eigenstates. Consequently, due to such inherent mathematical complexity, the geometric and physical interpretation of these sets of orthogonal complex vectors, being essential for the best understanding of the structure and properties of partially polarized 3D light, has not been addressed thoroughly. In this work, the geometric and physical features of sets of three orthonormal 3D Jones vectors are identified and analyzed, allowing one to obtain meaningful interpretations of any given mixed (partially polarized) 3D polarization state in terms of either the spectral or the characteristic decompositions. Among other results, it is found that, given a pure polarization state, any plane in space contains the polarization ellipse of a pure state that is orthogonal to it, and the mathematical expressions for the azimuth and ellipticity of such an ellipse are calculated in terms of the angular parameters determining said plane and the ellipticity of the given state. Furthermore, the spin vectors of the three polarization eigenstates are arranged in a peculiar spatial manner, such that they lie in a common plane. Beyond polarization phenomena, the approach presented also has potential applications in areas where 3 x 3 unitary matrices play a key role, like three-level quantum systems and gates for ternary quantum logic circuits

Ancient cultural landscapes in the valleys of Tormes and Corneja (Ávila)

El presente trabajo pretende ofrecer una visión diacrónica de la antigua ocupación humana en los valles del Tormes y del Corneja (Ávila), abarcando cronológicamente los momentos culturales incluidos entre la II Edad del Hierro y la Alta Edad Media (ss. ii a. C. - x d. C.). La información sobre los yacimientos procede tanto de prospecciones sistemáticas extensivas e intensivas, así como de algunas excavaciones arqueológicas. Se presenta así por primera vez un análisis de conjunto, diacrónico y comparativo, del poblamiento antiguo en esta zona serrana y de las dinámicas que marcaron su transformación durante la época romana y tardoantigua. Mediante el recurso a las Técnicas de Información Geográfica (TIG), se ha recopilado e incluido toda la información arqueológica relativa a los yacimientos documentados en esta zona, analizándola de forma combinada junto con aquella relativa a su contexto espacial (vías de comunicación, toponimia, recursos naturales, medio físico, etc.). Todo ello nos permite, por un lado, trazar la evolución del poblamiento en este territorio, ofreciendo una visión de largo alcance y, por otro, insertar este sector serrano en los procesos que definen este periodo en otras áreas próximas, en especial, en las vecinas tierras salmantinas y madrileñasThis paper offers a diachronic interpretation of the ancient human occupation of the Tormes and Corneja valleys (Ávila), chronologically including the cultural times between the II Iron Age to the High Middle Ages (2nd century BC - 10th century AD). The information on the deposits comes from extensive and intensive systematic surveys as well as some archaeological excavations. For the first time it is presented a diachronic and comparative analysis of the old settlement in this mountain area and of the dynamics that marked its transformation during the Roman period and Late Antiquity. By using Geographic Information Techniques (GIS), all the archaeological information related to the sites documented in this area has been compiled and analyzed together with that relating to its spatial context (ways of communication, toponymy, natural resources, physical environment, etc.). All this allows us to, on the one hand, trace the evolution of the settlement in this territory, offering a vision of long reach and, on the other hand, insert this sector serrano in the processes that define this period in other nearby areas, especially in the neighboring lands in Salamanca and Madri

High levels of auxin signalling define the stem-cell organizer of the vascular cambium

Wood, a type of xylem tissue, originates from cell proliferation of the vascular cambium. Xylem is produced inside, and phloem outside, of the cambium(1). Morphogenesis in plants is typically coordinated by organizer cells that direct the adjacent stem cells to undergo programmed cell division and differentiation. The location of the vascular cambium stem cells and whether the organizer concept applies to the cambium are currently unknown(2). Here, using lineage-tracing and molecular genetic studies in the roots of Arabidopsis thaliana, we show that cells with a xylem identity direct adjacent vascular cambial cells to divide and function as stem cells. Thus, these xylem-identity cells constitute an organizer. A local maximum of the phytohormone auxin, and consequent expression of CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIP III) transcription factors, promotes xylem identity and cellular quiescence of the organizer cells. Additionally, the organizer maintains phloem identity in a non-cell-autonomous fashion. Consistent with this dual function of the organizer cells, xylem and phloem originate from a single, bifacial stem cell in each radial cell file, which confirms the classical theory of a uniseriate vascular cambium(3). Clones that display high levels of ectopically activated auxin signalling differentiate as xylem vessels; these clones induce cell divisions and the expression of cambial and phloem markers in the adjacent cells, which suggests that a local auxin-signalling maximum is sufficient to specify a stem-cell organizer. Although vascular cambium has a unique function among plant meristems, the stem-cell organizer of this tissue shares features with the organizers of root and shoot meristems.Peer reviewe

Comprehensive microRNA profiling in B-cells of human centenarians by massively parallel sequencing

Background: MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression and play a critical role in development, homeostasis, and disease. Despite their demonstrated roles in age-associated pathologies, little is known about the role of miRNAs in human aging and longevity.Results: We employed massively parallel sequencing technology to identify miRNAs expressed in B-cells from Ashkenazi Jewish centenarians, i.e., those living to a hundred and a human model of exceptional longevity, and younger controls without a family history of longevity. With data from 26.7 million read

Multidisciplinary surgical approach for cerebrospinal fluid leak in children with complex head trauma

Abstract Introduction Post-traumatic cerebrospinal fluid leak from the anterior cranial fossa in children may be isolated or combined with severe facial and calvarial injury. Untreated leak may result with meningitis, hydrocephalus, and abnormal neurocognitive development. Patients and methods We present nine children, ages 4-16 years, with complicated craniofacial injury treated by a combined subcranial and intracranial approach. A continuous lumbar drainage was kept for several days, and prophylactic antibiotics and anti-convulsive medications were routinely given. A multidisciplinary approach including discussion before surgery about other surgical options (endoscopic extracranial and intracranial alone) were performed. Results None of the operated children had episodes of meningitis/leak after the combined approach, suggesting that appropriate sealing of the base of the skull has been achieved. There was no mortality, and the long-term follow-up showed good developmental and cosmetic results. Most of the children had significant brain contusions prior to surgery; however, these did not progress as minimal retraction was enabled by the extensive subcranial and intracranial approach. Conclusions Child's age, anatomy of the bone, extent of cranial injury, and clinical parameters should be seriously considered when choosing the technical methods as for sealing base of skull and reconstruction of facial/cranial bones. Young age does not seem to be a contraindication to the combined approach, thus, we recommend considering it in extensive base of skull fractures when concomitant cranial, maxillofacial, and orbital fractures coexist, as alternative options may not suffice in these cases

Interleukin-23 receptor expressing γδ T cells locally promote early atherosclerotic lesion formation and plaque necrosis in mice

Aims Atherosclerosis is a chronic inflammatory disease of the vessel wall controlled by local and systemic immune responses. The role of interleukin-23 receptor (IL-23R), expressed in adaptive immune cells (mainly T-helper 17 cells) and gamma delta T cells, in atherosclerosis is only incompletely understood. Here, we investigated the vascular cell types expressing IL-23R and addressed the function of IL-23R and gamma delta T cells in atherosclerosis. Methods and results IL-23R(+) cells were frequently found in the aortic root in contrast to the aorta in low-density lipoprotein receptor deficient IL-23R reporter mice (Ldlr(-/-)Il23r(gfp/+)), and mostly identified as gamma delta T cells that express IL-17 and GM-CSF. scRNA-seq confirmed gamma delta T cells as the main cell type expressing Il23r and Il17a in the aorta. Ldlr(-)(/)(-)Il23r(gfp/gfp) mice deficient in IL-23R showed a loss of IL-23R(+) cells in the vasculature, and had reduced atherosclerotic lesion formation in the aortic root compared to Ldlr(-/-) controls after 6 weeks of high-fat diet feeding. In contrast, Ldlr(-/-)Tcr delta(-/-) mice lacking all gamma delta T cells displayed unaltered early atherosclerotic lesion formation compared to Ldlr(-)(/-) mice. In both HFD-fed Ldlr(-/-)Il23r(gfp/gfp) and Ldlr(-/-)Tcr delta(-/-) mice a reduction in the plaque necrotic core area was noted as well as an expansion of splenic regulatory T cells. In vitro, exposure of bone marrow-derived macrophages to both IL-17A and GM-CSF induced cell necrosis, and necroptotic RIP3K and MLKL expression, as well as inflammatory mediators. Conclusions IL-23R(+) gamma delta T cells are predominantly found in the aortic root rather than the aorta and promote early atherosclerotic lesion formation, plaque necrosis, and inflammation at this site. Targeting IL-23R may thus be explored as a therapeutic approach to mitigate atherosclerotic lesion development