59 research outputs found
Lambda-N scattering length from the reaction gamma d -> K^+ Lambda n
The perspects of utilizing the strangeness-production reaction gamma d -> K^+
Lambda n for the determination of the Lambda n low-energy scattering parameters
are investigated. The spin observables that need to be measured in order to
isolate the Lambda n singlet (1S0) and triplet (3S1) states are identified.
Possible kinematical regions where the extraction of the Lambda n scattering
lengths might be feasible are discussed.Comment: 8 pages, 4 figure
High resolution study of the Lambda p final state interaction in the reaction p + p -> K+ + (Lambda p)
The reaction pp -> K+ + (Lambda p) was measured at Tp=1.953 GeV and Theta = 0
deg with a high missing mass resolution in order to study the Lambda p final
state interaction. The large final state enhancement near the Lambda p
threshold can be described using the standard Jost-function approach. The
singlet and triplet scattering lengths and effective ranges are deduced by
fitting simultaneously the Lambda p invariant mass spectrum and the total cross
section data of the free Lambda p scattering.Comment: submitted to Physics Letters B, 10 pages, 3 figure
Exploring Hyperons and Hypernuclei with Lattice QCD
In this work we outline a program for lattice QCD that would provide a first
step toward understanding the strong and weak interactions of strange baryons.
The study of hypernuclear physics has provided a significant amount of
information regarding the structure and weak decays of light nuclei containing
one or two Lambda's, and Sigma's. From a theoretical standpoint, little is
known about the hyperon-nucleon interaction, which is required input for
systematic calculations of hypernuclear structure. Furthermore, the
long-standing discrepancies in the P-wave amplitudes for nonleptonic hyperon
decays remain to be understood, and their resolution is central to a better
understanding of the weak decays of hypernuclei. We present a framework that
utilizes Luscher's finite-volume techniques in lattice QCD to extract the
scattering length and effective range for Lambda-N scattering in both QCD and
partially-quenched QCD. The effective theory describing the nonleptonic decays
of hyperons using isospin symmetry alone, appropriate for lattice calculations,
is constructed.Comment: 24 pages, 7 figure
Long non-coding RNAs H19 and NKILA are associated with the risk of death and lacunar stroke in the elderly population
Introduction: Differential expression of long non-coding RNAs (lncRNAs) is a hallmark of cardiovascular aging, cerebrovascular diseases, and neurodegenerative disorders. This research article investigates the association between a panel of lncRNAs and the risk of death and ischemic stroke in a cohort of non-institutionalized elderly subjects.
Method: A total of 361 healthy individuals aged 75 years old, prospectively recruited in the Vienna Transdanube Aging (VITA) cohort, were included. Expression of lncRNAs at baseline was assessed using quantitative polymerase chain reaction PCR with pre-amplification reaction, using 18S for normalization. The primary endpoint was all-cause mortality; the secondary endpoint was the incidence of new ischemic brain lesions. Death was assessed over a 14-year follow-up, and ischemic brain lesions were evaluated by magnetic resonance imaging (MRI) over a 90-month follow-up. Ischemic brain lesions were divided into large brain infarcts (Ø≥ 1.5 cm) or lacunes (Ø< 1.5 cm) RESULTS: The primary endpoint occurred in 53.5 % of the study population. The incidence of the secondary endpoint was 16 %, with a 3.3 % being large brain infarcts, and a 12.7 % lacunes. After adjustment for potential confounders, the lncRNA H19 predicted the incidence of the primary endpoint (HR 1.194, 95 % C.I. 1.012-1.409, p = 0.036), whereas the lncRNA NKILA was associated with lacunar stroke (HR 0.571, 95 % C.I. 0.375-0.868, p = 0.006).
Conclusion: In a prospective cohort of non-institutionalized elderly subjects, high levels of lncRNA H19 are associated with a higher risk of death, while low levels of lncRNA NKILA predict an increased risk of lacunar stroke
Close-to-threshold Meson Production in Hadronic Interactions
Studies of meson production at threshold in the hadron--hadron interaction
began in the fifties when sufficient energies of accelerated protons were
available. A strong interdependence between developments in accelerator
physics, detector performance and theoretical understanding led to a unique
vivid field of physics. Early experiments performed with bubble chambers
revealed already typical ingredients of threshold studies, which were
superseded by more complete meson production investigations at the nucleon beam
facilities TRIUMF, LAMPF, PSI, LEAR and SATURNE. Currently, with the advent of
the new cooler rings as IUCF, CELSIUS and COSY the field is entering a new
domain of precision and the next step of further progress.
The analysis of this new data in the short range limit permits a more
fundamental consideration and a quantitative comparison of the production
processes for different mesons in the few--body final states. The
interpretation of the data take advantage of the fact that production reactions
close-to-threshold are characterized by only a few degrees of freedom between a
well defined combination of initial and exit channels. Deviations from
predictions of phase-space controlled one-meson-exchange models are indications
of new and exciting physics. Precision data on differential cross sections,
isospin and spin observables -- partly but by no means adequately available --
are presently turning up on the horizon. There is work for the next years and
excitement of the physics expected. Here we try to give a brief and at the same
time comprehensive overview of this field of hadronic threshold production
studies.Comment: 100 pages, Review article to be published in Prog. Part. Nucl. Phys.
Vol. 49, issue 1 (2002
Haematopoietic SCT in severe autoimmune diseases: updated guidelines of the European Group for Blood and Marrow Transplantation
In 1997, the first consensus guidelines for haematopoietic SCT (HSCT) in autoimmune diseases (ADs) were published, while an international coordinated clinical programme was launched. These guidelines provided broad principles for the field over the following decade and were accompanied by comprehensive data collection in the European Group for Blood and Marrow Transplantation (EBMT) AD Registry. Subsequently, retrospective analyses and prospective phase I/II studies generated evidence to support the feasibility, safety and efficacy of HSCT in several types of severe, treatment-resistant ADs, which became the basis for larger-scale phase II and III studies. In parallel, there has also been an era of immense progress in biological therapy in ADs. The aim of this document is to provide revised and updated guidelines for both the current application and future development of HSCT in ADs in relation to the benefits, risks and health economic considerations of other modern treatments. Patient safety considerations are central to guidance on patient selection and HSCT procedural aspects within appropriately experienced and Joint Accreditation Committee of International Society for Cellular Therapy and EBMT accredited centres. A need for prospective interventional and non-interventional studies, where feasible, along with systematic data reporting, in accordance with EBMT policies and procedures, is emphasized
Autologous haematopoietic stem cell transplantation for treatment of multiple sclerosis
Autologous haematopoietic stem cell transplantation (AHSCT) is a multistep procedure that enables destruction of the immune system and its reconstitution from haematopoietic stem cells. Originally developed for the treatment of haematological malignancies, the procedure has been adapted for the treatment of severe immune-mediated disorders. Results from ~20 years of research make a compelling case for selective use of AHSCT in patients with highly active multiple sclerosis (MS), and for controlled trials. Immunological studies support the notion that AHSCT causes qualitative immune resetting, and have provided insight into the mechanisms that might underlie the powerful treatment effects that last well beyond recovery of immune cell numbers. Indeed, studies have demonstrated that AHSCT can entirely suppress MS disease activity for 4–5 years in 70–80% of patients, a rate that is higher than those achieved with any other therapies for MS. Treatment-related mortality, which was 3.6% in studies before 2005, has decreased to 0.3% in studies since 2005. Current evidence indicates that the patients who are most likely to benefit from and tolerate AHSCT are young, ambulatory and have inflammatory MS activity. Clinical trials are required to rigorously test the efficacy, safety and cost-effectiveness of AHSCT against highly active MS drugs
Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised protons
Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise. © 2015
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