912 research outputs found

    Long-distance structure of the X(3872)

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    We investigate heavy quark symmetries for heavy meson hadronic molecules, and explore the consequences of assuming the X(3872) and Zb(10610)Z_b(10610) as an isoscalar DDˉD\bar D^* and an isovector BBˉB\bar B^* hadronic molecules, respectively. The symmetry allows to predict new hadronic molecules, in particular we find an isoscalar 1++1^{++} BBˉB\bar B^* bound state with a mass about 10580 MeV and the isovector charmonium partners of the Zb(10610)Z_b(10610) and the Zb(10650)Z_b(10650) states. Next, we study the X(3872)D0Dˉ0π0X(3872) \to D^0 \bar D^0\pi^0 three body decay. This decay mode is more sensitive to the long-distance structure of the X(3872) resonance than its J/ψππJ/\psi\pi\pi and J/ψ3πJ/\psi3\pi decays, which are mainly controlled by the short distance part of the X(3872) molecular wave function. We discuss the D0Dˉ0D^0 \bar D^0 final state interactions, which in some situations become quite important. Indeed in these cases, a precise measurement of this partial decay width could provide precise information on the interaction strength between the D()Dˉ()D^{(*)}\bar D^{(*)} charm mesons.Comment: Talk presented at the "XI International Conference on Hyperons, Charm and Beauty Hadrons (BEACH 2014)", Birmingham (U.K.), July 201

    Rapid Syphilis Tests as Catalysts for Health Systems Strengthening: A Case Study from Peru.

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    OBJECTIVES: Untreated maternal syphilis leads to adverse pregnancy outcomes. The use of point of care tests (POCT) offers an opportunity to improve screening coverage for syphilis and other aspects of health systems. Our objective is to present the experience of the introduction of POCT for syphilis in Peru and describe how new technology can catalyze health system strengthening. METHODS: The study was implemented from September 2009-November 2010 to assess the feasibility of the use of a POCT for syphilis for screening pregnant women in Lima, Peru. Outcomes measured included access to syphilis screening, treatment coverage, partner treatment, effect on patient flow and service efficiency, acceptability among providers and patients, and sustainability. RESULTS: Before the introduction of POCT, a pregnant woman needed 6 visits to the health center in 27 days before she received her syphilis result. We trained 604 health providers and implemented the POCT for syphilis as the "two for one strategy", offering with one finger stick both syphilis and HIV testing. Implementation of the POCT resulted in testing and treatment on the first visit. Screening and treatment coverages for syphilis improved significantly compared with the previous year. Implementation of POCT has been scaled up nationally since the study ended, and coverages for screening, treatment and partner treatment have remained over 92%. CONCLUSIONS: Implementation of POCT for syphilis proved feasible and acceptable, and led to improvement in several aspects of health services. For the process to be effective we highlight the importance of: (1) engaging the authorities; (2) dissipating tensions between providers and identifying champions; (3) training according to the needs; (4) providing monitoring, supervision, support and recognition; (5) sharing results and discussing actions together; (6) consulting and obtaining feedback from users; and (7) integrating with other services such as with rapid HIV testing

    Deriving the existence of BBˉB\bar{B}^* bound states from the X(3872) and Heavy Quark Symmetry

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    We discuss the possibility and the description of bound states between BB and Bˉ\bar{B}^* mesons. We argue that the existence of such a bound state can be deduced from (i) the weakly bound X(3872) state, (ii) certain assumptions about the short range dynamics of the DDˉD\bar{D}^* system and (iii) heavy quark symmetry. From these assumptions the binding energy of the possible BBˉB\bar{B}^* bound states is determined, first in a theory containing only contact interactions which serves as a straightforward illustration of the method, and then the effects of including the one pion exchange potential are discussed. In this latter case three isoscalar states are predicted: a positive and negative C-parity 3S13D1^3S_1-{}^3D_1 state with a binding energy of 20MeV20\,{\rm MeV} and 6MeV6\,{\rm MeV} below threshold respectively, and a positive C-parity 3P0^3P_0 shallow state located almost at the BBˉB\bar{B}^* threshold. However, large uncertainties are generated as a consequence of the 1/mQ1/m_Q corrections from heavy quark symmetry. Finally, the newly discovered isovector Zb(10610)Z_b(10610) state can be easily accommodated within the present framework by a minor modification of the short range dynamics.Comment: 21 pages, 3 figures; a sign error in the potential has been corrected and new predictions have been compute

    Extracellular Vesicles and Intercellular Communication in the Central Nervous System

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    Neurons and glial cells of the central nervous system (CNS) release extracellular vesicles (EVs) to the interstitial fluid of the brain and spinal cord parenchyma. EVs contain proteins, nucleic acids and lipids that can be taken up by, and modulate the behaviour of, neighbouring recipient cells. The functions of EVs have been extensively studied in the context of neurodegenerative diseases. However, mechanisms involved in EV‐mediated neuron–glial communication under physiological conditions or healthy ageing remain unclear. A better understanding of the myriad roles of EVs in CNS homeostasis is essential for the development of novel therapeutics to alleviate and reverse neurological disturbances of ageing. Proteomic studies are beginning to reveal cell type‐specific EV cargo signatures that may one day allow us to target specific neuronal or glial cell populations in the treatment of debilitating neurological disorders. This review aims to synthesise the current literature regarding EV‐mediated cell–cell communication in the brain, predominantly under physiological conditions

    Nuclear forces from chiral EFT: The unfinished business

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    In spite of the great progress we have seen in recent years in the derivation of nuclear forces from chiral effective field theory (EFT), some important issues are still unresolved. In this contribution, we discuss the open problems which have particular relevance for microscopic nuclear structure, namely, the proper renormalization of chiral nuclear potentials and sub-leading many-body forces.Comment: 16 pages, 3 figures; contribution to J. Phys. G, Special Issue, Focus Section: Open Problems in Nuclear Structur

    Surgical management of enchondroma with joint transfer: a case report

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    The enchondromas are the most common benign bone tumor in the hands, mainly in young patients and its treatment is surgical in most cases due to its possible complications avoided through different procedures such as joint transfer, which allows to maintain a good quality of life for the patient. We present the case of a 42-year-old woman who came to the clinic for blunt trauma in the right hand where she was incidentally diagnosed with enchondroma on the third finger of the proximal interphalangeal joint of the right hand. Articular transfer of the proximal interphalangeal joint was performed. Second toe on the right, at 6 weeks corroborates correct evolution with bone consolidation of the articular transfer grade III and donor zone grade II, without infection complications, the correct recovery of the extensor movement range of this joint improving so their state of life should be the main objective of these procedures

    Hidden charm and bottom molecular states

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    We investigate heavy quark symmetries for heavy light meson-antimeson systems in a contact-range effective field theory. In the SU(3) light flavor limit, the leading order Lagrangian respecting heavy quark spin symmetry contains four independent counter-terms. Neglecting 1/mQ corrections, three of these low energy constants can be determ1ined by theorizing a molecular description of the X(3872) and Zb(10610) states. Thus, we can predict new hadronic molecules, in particular the isovector charmonium partners of the Zb(10610) and the Zb(10650) states. We also discuss hadron molecules composed of a heavy meson and a doubly-heavy baryon, which would be related to the heavy meson-antimeson molecules thanks to the heavy antiquark-diquark symmetry. Finally, we also study the X(3872)→D0D¯0π0 decay, which is not only sensitive to the short distance part of the X(3872) molecular wave function, as the J/ψππ and J/ψ3π X(3872) decay modes are, but it is also affected by the long-distance structure of the resonance. Furthermore, this decay might provide some information on the interaction between the DD¯ charm mesons

    Genomic epidemiology of NDM-1-encoding plasmids in latin American clinical isolates reveals insights into the evolution of multidrug resistance

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    Bacteria that produce the broad-spectrum Carbapenem antibiotic NewDelhi Metallo-b-lactamase (NDM) place a burden on health care systems worldwide, due to the limited treatment options for infections caused by them and the rapid global spread of this antibiotic resistancemechanism.Although it is believed that theassociated resistancegenebla NDM-1 originated inAcinetobacter spp., the role of Enterobacteriaceae in its dissemination remains unclear. In this study, we usedwhole genome sequencing to investigate the dissemination dynamics of blaNDM-1-positive plasmids in a set of 21 clinical NDM-1-positive isolates from Colombia and Mexico (Providencia rettgeri, Klebsiella pneumoniae, and Acinetobacter baumannii) aswell as six representative NDM-1-positive Escherichia coli transconjugants. Additionally, the plasmids from three representative P. rettgeri isolates were sequenced by PacBio sequencing and finished. Our results demonstrate the presence of previously reported plasmids from K. pneumoniae and A. baumannii in different genetic backgrounds and geographically distant locations in Colombia. Three new previously unclassified plasmids were also identified in P. rettgeri from Colombia and Mexico, plus an interesting genetic link between NDM-1-positive P. rettgeri from distant geographic locations (Canada, Mexico, Colombia, and Israel) without any reported epidemiological links was discovered. Finally, we detected a relationship between plasmids present in P. rettgeri and plasmids from A. baumannii and K. pneumoniae. Overall, our findings suggest a Russian dollmodel for the dissemination of blaNDM-1 in LatinAmerica,with P. rettgeri playing a central role in this process, andrevealnewinsights into the evolution and disseminationof plasmids carrying such antibiotic resistance genes

    TRY plant trait database - enhanced coverage and open access

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    Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
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