5,683 research outputs found
Commissioning ATLAS and CMS with top quarks
The large ttbar production cross-section at the LHC suggests the use of top
quark decays to calibrate several critical parts of the detectors, such as the
trigger system, the jet energy scale and b-tagging.Comment: 6 pages, 5 figures. Talk given at `V Workshop Italiano sulla Fisica
pp a LHC', Perugia, Italy, 30 January - 2 February 200
Follow-up after curative resection for gastric cancer. Is it time to tailor it?
There is still no consensus on the follow-up frequency and regimen after curative resection for gastric cancer. Moreover, controversy exists regarding the utility of follow-up in improving survival, and the recommendations of experts and societies vary considerably. The main reason to establish surveillance programs is to diagnose tumor recurrence or metachronous cancers early and to thereby provide prompt treatment and prolong survival. In the setting of gastric malignancies, other reasons have been put forth: (1) the detection of adverse effects of a previous surgery, such as malnutrition or digestive sequelae; (2) the collection of data; and (3) the identification of psychological and/or social problems and provision of appropriate support to the patients. No randomized controlled trials on the role of follow-up after curative resection of gastric carcinoma have been published. Herein, the primary retrospective series and systematic reviews on this subject are analyzed and discussed. Furthermore, the guidelines from international and national scientific societies are discussed. Follow-up is recommended by the majority of institutions; however, there is no real evidence that follow-up can improve long-term survival rates. Several studies have demonstrated that it is possible to stratify patients submitted to curative gastrectomy into different classes according to the risk of recurrence. Furthermore, promising studies have identified several molecular markers that are related to the risk of relapse and to prognosis. Based on these premises, a promising strategy will be to tailor follow-up in relation to the patient and tumor characteristics, molecular marker status, and individual risk of recurrence
Set-Theoretic Types for Polymorphic Variants
Polymorphic variants are a useful feature of the OCaml language whose current
definition and implementation rely on kinding constraints to simulate a
subtyping relation via unification. This yields an awkward formalization and
results in a type system whose behaviour is in some cases unintuitive and/or
unduly restrictive. In this work, we present an alternative formalization of
poly-morphic variants, based on set-theoretic types and subtyping, that yields
a cleaner and more streamlined system. Our formalization is more expressive
than the current one (it types more programs while preserving type safety), it
can internalize some meta-theoretic properties, and it removes some
pathological cases of the current implementation resulting in a more intuitive
and, thus, predictable type system. More generally, this work shows how to add
full-fledged union types to functional languages of the ML family that usually
rely on the Hindley-Milner type system. As an aside, our system also improves
the theory of semantic subtyping, notably by proving completeness for the type
reconstruction algorithm.Comment: ACM SIGPLAN International Conference on Functional Programming, Sep
2016, Nara, Japan. ICFP 16, 21st ACM SIGPLAN International Conference on
Functional Programming, 201
Spatial Bloch oscillations of a quantum gas in a "beat-note" superlattice
We report the experimental realization of a new kind of optical lattice for
ultra-cold atoms where arbitrarily large separation between the sites can be
achieved without renouncing to the stability of ordinary lattices. Two
collinear lasers, with slightly different commensurate wavelengths and
retroreflected on a mirror, generate a superlattice potential with a periodic
"beat-note" profile where the regions with large amplitude modulation provide
the effective potential minima for the atoms. To prove the analogy with a
standard large spacing optical lattice we study Bloch oscillations of a Bose
Einstein condensate with negligible interactions in the presence of a small
force. The observed dynamics between sites separated by ten microns for times
exceeding one second proves the high stability of the potential. This novel
lattice is the ideal candidate for the coherent manipulation of atomic samples
at large spatial separations and might find direct application in atom-based
technologies like trapped atom interferometers and quantum simulators.Comment: 5 pages, 4 figure
Spigelian hernia: a case report and review of the literature
Spigelian hernia is a rare abdominal hernia that occurs through Spigelian aponeurosis.
The Authors present a case of Spigelian hernia associated with narrowing of sigmoid colon and diverticular pathology.They also described historical background, surgical anatomy and etiopathogenesis of this hernia. By a remarkable revision of literature, they sum up epidemiology and clinical features of Spigelian hernia. Furthermore, they discuss diagnostic and therapeutic principles
Ferromagnetically contacted carbon nanotube quantum dots
This thesis presents research into spin-transport in Carbon nanotube quantum dots. Sputtered Permalloy electrodes designed with shape anisotropy were used to contact Carbon nanotubes grown by chemicalvapour deposition in lateral spin-valve structures. The magnetoresistance of these spin-valves were measured at low-temperatures and as a function of the charge state of the quantum dots. Two conductance regimes were measured in a Carbon nanotube spinvalve with Permalloy nucleation pads. At high bias outside of the coulomb blockade regime a ~ 10% magnetoresistance was measured that is analogous to giant-magnetoresistance, in that it is due to spindependent scattering at the ferromagnet-Carbon nanotube interfaces. At lower bias the device enters the coulomb blockade regime and the magnetoresistance observed develops a different structure, over a larger field range, together with the development of an offset in conductance between saturations. The maximum value of this MR was MR ~ 245% and it was attributed to changes in the induced charge on the quantum dot. By modifying the design of the Permalloy electrodes, a single domain state at the point of contact of the Carbon nanotube was achieved. A well defined anti-parallel state of the Permalloy electrodes, with associated changes in the conduction of the devices was observed, yet the conductance offset remained, with a maximum MR of ~ 60%. The positions of the coulomb peaks were measured during magnetic reversal of the electrodes, showing the change in induced charge on the quantum dot, with a maximum MR ~ 350%. Predictions of device transport based on the magneto-coulomb effect and spin-dependent interfacial phase shifts were compared to experimental results and found to not fit the observed behaviour. This led to the conclusion that changes in the charge state of the quantum dots must be due to a fixed spin-quantisation axis intrinsic to the Carbon nanotube.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Clinical Practice Guidelines for Childbearing Female Candidates for Bariatric Surgery, Pregnancy, and Post-partum Management After Bariatric Surgery
Emerging evidence suggests that bariatric surgery improves pregnancy outcomes of women with obesity by reducing the rates of gestational diabetes, pregnancy-induced hypertension, and macrosomia. However, it is associated with an increased risk of a small-for-gestational-age fetus and prematurity. Based on the work of a multidisciplinary task force, we propose clinical practice recommendations for pregnancy management following bariatric surgery. They are derived from a comprehensive review of the literature, existing guidelines, and expert opinion covering the preferred type of surgery for women of childbearing age, timing between surgery and pregnancy, contraception, systematic nutritional support and management of nutritional deficiencies, screening and management of gestational diabetes, weight gain during pregnancy, gastric banding management, surgical emergencies, obstetrical management, and specific care in the postpartum period and for newborns
Truncation, validity, uncertainties
The truncation of the standard-model effective field theory, its validity andthe associated uncertainties have been discussed in meetings of the LHC EFT WG.Proposals were made by participants to address these issues. No consensus wasreached and no formal recommendation is therefore put forward at this time.None of the proposals has been approved or validated and further work is neededto establish a prescription. This note aims at summarizing the proposals andpoints of debate.<br
Truncation, validity, uncertainties
The truncation of the standard-model effective field theory, its validity andthe associated uncertainties have been discussed in meetings of the LHC EFT WG.Proposals were made by participants to address these issues. No consensus wasreached and no formal recommendation is therefore put forward at this time.None of the proposals has been approved or validated and further work is neededto establish a prescription. This note aims at summarizing the proposals andpoints of debate.<br
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