136 research outputs found
Asymptotic properties of Born-improved amplitudes with gauge bosons in the final state
For processes with gauge bosons in the final state we show how to
continuously connect with a single Born-improved amplitude the resonant region,
where resummation effects are important, with the asymptotic region far away
from the resonance, where the amplitude must reduce to its tree-level form.
While doing so all known field-theoretical constraints are respected, most
notably gauge-invariance, unitarity and the equivalence theorem. The
calculations presented are based on the process , mediated by a
possibly resonant Higgs boson; this process captures all the essential
features, and can serve as a prototype for a variety of similar calculations.
By virtue of massive cancellations the resulting closed expressions for the
differential and total cross-sections are particularly compact.Comment: 23 pages, Latex, 4 Figures, uses axodra
Hadronic final states in deep-inelastic scattering with Sherpa
We extend the multi-purpose Monte-Carlo event generator Sherpa to include
processes in deeply inelastic lepton-nucleon scattering. Hadronic final states
in this kinematical setting are characterised by the presence of multiple
kinematical scales, which were up to now accounted for only by specific
resummations in individual kinematical regions. Using an extension of the
recently introduced method for merging truncated parton showers with
higher-order tree-level matrix elements, it is possible to obtain predictions
which are reliable in all kinematical limits. Different hadronic final states,
defined by jets or individual hadrons, in deep-inelastic scattering are
analysed and the corresponding results are compared to HERA data. The various
sources of theoretical uncertainties of the approach are discussed and
quantified. The extension to deeply inelastic processes provides the
opportunity to validate the merging of matrix elements and parton showers in
multi-scale kinematics inaccessible in other collider environments. It also
allows to use HERA data on hadronic final states in the tuning of hadronisation
models.Comment: 32 pages, 22 figure
PYTHIA 6.4 Physics and Manual
The PYTHIA program can be used to generate high-energy-physics `events', i.e.
sets of outgoing particles produced in the interactions between two incoming
particles. The objective is to provide as accurate as possible a representation
of event properties in a wide range of reactions, within and beyond the
Standard Model, with emphasis on those where strong interactions play a role,
directly or indirectly, and therefore multihadronic final states are produced.
The physics is then not understood well enough to give an exact description;
instead the program has to be based on a combination of analytical results and
various QCD-based models. This physics input is summarized here, for areas such
as hard subprocesses, initial- and final-state parton showers, underlying
events and beam remnants, fragmentation and decays, and much more. Furthermore,
extensive information is provided on all program elements: subroutines and
functions, switches and parameters, and particle and process data. This should
allow the user to tailor the generation task to the topics of interest.Comment: 576 pages, no figures, uses JHEP3.cls. The code and further
information may be found on the PYTHIA web page:
http://www.thep.lu.se/~torbjorn/Pythia.html Changes in version 2: Mistakenly
deleted section heading for "Physics Processes" reinserted, affecting section
numbering. Minor updates to take into account referee comments and new colour
reconnection option
D* Production in Deep Inelastic Scattering at HERA
This paper presents measurements of D^{*\pm} production in deep inelastic
scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The
data have been taken with the ZEUS detector at HERA. The decay channel
(+ c.c.) has been used in the study. The
cross section for inclusive D^{*\pm} production with
and is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region
{ GeV and }. Differential cross
sections as functions of p_T(D^{*\pm}), and are
compared with next-to-leading order QCD calculations based on the photon-gluon
fusion production mechanism. After an extrapolation of the cross section to the
full kinematic region in p_T(D^{*\pm}) and (D^{*\pm}), the charm
contribution to the proton structure function is
determined for Bjorken between 2 10 and 5 10.Comment: 17 pages including 4 figure
Isolated tau leptons in events with large missing transverse momentum at HERA
A search for events containing isolated tau leptons and large missing
transverse momentum, not originating from the tau decay, has been performed
with the ZEUS detector at the electron-proton collider HERA, using 130 pb^-1 of
integrated luminosity. A search was made for isolated tracks coming from
hadronic tau decays. Observables based on the internal jet structure were
exploited to discriminate between tau decays and quark- or gluon-induced jets.
Three tau candidates were found, while 0.40 +0.12 -0.13 were expected from
Standard Model processes, such as charged current deep inelastic scattering and
single W-boson production. To search for heavy-particle decays, a more
restrictive selection was applied to isolate tau leptons produced together with
a hadronic final state with high transverse momentum. Two candidate events
survive, while 0.20 +-0.05 events are expected from Standard Model processes.Comment: 28 pages, 4 figures, 3 tables, accepted by Phys. Lett. B. Updated
with minor changes to the text requested by the journal refere
Anesthetic management of a patient with a double inferior vena cava and pulmonary alveolar proteinosis who underwent bilateral living-donor lobar lung transplantation.
A 43-year-old woman with pulmonary fibrosis secondary to pulmonary alveolar proteinosis was scheduled to undergo lung transplantation. Before the lung transplantation, she had undergone multiple whole-lung lavage procedures on extracorporeal circulation (ECC), which had caused scarring of the right femoral subcutaneous tissues. Preoperative examination revealed a double inferior vena cava (IVC) with interiliac communication, and the left IVC ended at the left renal vein. Surgical exposure of the right femoral vessels was performed immediately after anesthetic induction for emergent vascular access to establish an ECC. Cardiopulmonary collapse did not occur and the ECC was not required until lung resection. The lung transplantation was completed uneventfully. Congenital IVC anomaly is rare, but may make cannulation through the femoral vein difficult. Scarring of the subcutaneous tissue could result in a difficult "percutaneous" approach to the vessels. Evaluation of the vascular anatomy related to the establishment of an ECC is important before lung transplantation
Chronic lymphocytic leukaemia Australasian consensus practice statement
Chronic lymphocytic leukaemia (CLL) is the most common haematological malignancy in Australia and New Zealand (ANZ). Considerable changes to diagnostic and management algorithms have occurred within the last decade. The availability of next-generation sequencing and measurable residual disease assessment by flow cytometry allow for advanced prognostication and response assessments. Novel therapies, including inhibitors of Bruton's tyrosine kinase (BTKi) and B-cell lymphoma 2 (BCL2) inhibitors, have transformed the treatment landscape for both treatment-naïve and relapsed/refractory disease, particularly for patients with high-risk genetic aberrations. Recommendations regarding appropriate supportive management continue to evolve, and special considerations are required for patients with CLL with respect to the global SARS-CoV-2 pandemic. The unique funding and treatment environments in Australasia highlight the need for specific local guidance with respect to the investigation and management of CLL. This consensus practice statement was developed by a broadly representative group of ANZ experts in CLL with endorsement by peak haematology bodies, with a view to providing this standardised guidance
The urgent need for integrated science to fight COVID-19 pandemic and beyond
The COVID-19 pandemic has become the leading societal concern. The pandemic has shown that the public health
concern is not only a medical problem, but also afects society as a whole; so, it has also become the leading scientifc
concern. We discuss in this treatise the importance of bringing the world’s scientists together to fnd efective solu‑
tions for controlling the pandemic. By applying novel research frameworks, interdisciplinary collaboration promises to
manage the pandemic’s consequences and prevent recurrences of similar pandemics
Paleobiology of titanosaurs: reproduction, development, histology, pneumaticity, locomotion and neuroanatomy from the South American fossil record
Fil: García, Rodolfo A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Salgado, Leonardo. Instituto de Investigación en Paleobiología y Geología. General Roca. Río Negro; ArgentinaFil: Fernández, Mariela. Inibioma-Centro Regional Universitario Bariloche. Bariloche. Río Negro; ArgentinaFil: Cerda, Ignacio A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Carabajal, Ariana Paulina. Museo Carmen Funes. Plaza Huincul. Neuquén; ArgentinaFil: Otero, Alejandro. Museo de La Plata. Universidad Nacional de La Plata; ArgentinaFil: Coria, Rodolfo A.. Instituto de Paleobiología y Geología. Universidad Nacional de Río Negro. Neuquén; ArgentinaFil: Fiorelli, Lucas E.. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica. Anillaco. La Rioja; Argentin
Anthracycline-based chemotherapy as primary treatment for intravascular lymphoma
Background: Optimal therapeutic management of intravascular lymphoma (IVL) lacks precise guidelines. Patients and methods: The clinico-pathological features of 38 HIV-negative patients with IVL were reviewed to define efficacy of chemotherapy in these malignancies. Clinical characteristics of 22 patients treated with chemotherapy and of 16 untreated patients were compared in order to understand better the impact and causes of potential patient selection. Results: Median age was 70 years (range 34-90), with a male/female ratio of 0.9; 23 (61%) patients had Eastern Cooperative Oncology Group performance status (ECOG-PS) >1; 21 (55%) had systemic symptoms. Cutaneous lesions and anemia were significantly more common among patients treated with chemotherapy; central nervous system (CNS) and renal involvement were significantly more common among untreated patients. Chemotherapy was associated with a response rate of 59% and a 3-year overall survival of 33 \ub1 11%. Five of six patients with CNS involvement received chemotherapy: four of them died early; only one patient, treated with adriamycin, cyclophosphamide, vincristine, methotrexate, bleomycin and prednisolone (MACOP-B) followed by high-dose chemotherapy and autologous stem cell transplantation (ASCT), was alive at 19 months. High-dose chemotherapy supported by ASCT was indicated at diagnosis in another patient (43 years of age, stage I), who was alive at 71 months, and at relapse after cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) in two patients who died early after transplantation. PS 641, disease limited to the skin, stage I, and use of chemotherapy were independently associated with better outcome. Conclusions: Anthracycline-based chemotherapy is the standard treatment for IVL. However, survival is disappointing, with a relevant impact of diagnostic delay and lethal complications. More intensive combinations, containing drugs with higher CNS bioavailability, are needed in cases with brain involvement, and the role of high-dose chemotherapy supported by ASCT should be further investigated in younger patients with unfavorable features
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