1,992 research outputs found
The detailed simulation of the CMS detector
The CMS Collaboration developed a detailed simulation of the detector which is integrated in the software framework CMSSW. The simulation is based on the Geant4 tool for the description of particles interactions with the detector material. Care is given to the detailed description of the detector geometry. The simulation software is fully operational and it is currently under validation using real data from testbeams and from commissioning with cosmic rays
A Categorical Framework for Quantum Theory
Underlying any theory of physics is a layer of conceptual frames. They
connect the mathematical structures used in theoretical models with physical
phenomena, but they also constitute our fundamental assumptions about reality.
Many of the discrepancies between quantum physics and classical physics
(including Maxwell's electrodynamics and relativity) can be traced back to
these categorical foundations. We argue that classical physics corresponds to
the factual aspects of reality and requires a categorical framework which
consists of four interdependent components: boolean logic, the
linear-sequential notion of time, the principle of sufficient reason, and the
dichotomy between observer and observed. None of these can be dropped without
affecting the others. However, in quantum theory the reduction postulate also
addresses the "status nascendi" of facts, i.e., their coming into being.
Therefore, quantum phyics requires a different conceptual framework which will
be elaborated in this article. It is shown that many of its components are
already present in the standard formalisms of quantum physics, but in most
cases they are highlighted not so much from a conceptual perspective but more
from their mathematical structures. The categorical frame underlying quantum
physics includes a profoundly different notion of time which encompasses a
crucial role for the present.Comment: 35 pages, 1 figur
Newborn of mothers affected by autoimmune thyroiditis: the importance of thyroid function monitoring in the first months of life
<p>Abstract</p> <p>Background</p> <p>evaluation of thyroid function in neonates born from mothers affected by autoimmune thyroiditis in order to define if a precise follow-up is necessary for these children. The influence of maternal thyroid peroxidase antibody (TPOAb) and L-thyroxine therapy during pregnancy on neonatal thyroid function was also investigated.</p> <p>Methods</p> <p>129 neonates were tested for thyroid function by measurement of free thyroxine (FT4) and thyroid stimulating hormone (TSH) in 3<sup>th </sup>day, 15<sup>th </sup>day and at one month of life. TPOAb were measured in all patients; periodical control of thyroid function were performed until 6 months of life if Ab were positive. Data concerning etiology of maternal hypothyroidism and maternal replacement therapy with L-thyroxine during pregnancy were retrospectively collected.</p> <p>Results</p> <p>28% neonates showed at least a mild increase of TSH value at the different determinations. In the majority of them, a spontaneous completely normalisation of TSH value was observed within the first month life. L-thyroxine replacement therapy was started in 3 neonates. TPOAb titer and maternal L-thyroxine replacement therapy were not related to alteration of thyroid hormone function in our study population.</p> <p>Conclusions</p> <p>transient mild elevation of serum TSH above the normal reference value for age is frequently observed in the first month of life in infants born from mothers affected by autoimmune thyroiditis. Persistent hyperthyrotropinemia requiring replacement therapy is observed in 2.2% of these neonates. According to our experience, follow-up is recommended in these newborns; the most accurate and not invasive way to carefully monitor these infants after neonatal screening for CH seems to be serum-testing TSH between 2<sup>nd</sup>and 4<sup>th </sup>week of life.</p
High Voltage System for the CMS Electromagnetic Calorimeter
The CMS electromagnetic calorimeter (ECAL) is made of about 75000 lead tungstate crystals. The 61200 crystals of the barrel part are read by avalanche photodiodes (APD) with internal amplification of the signal. Since the gain strongly depends on the bias voltage, the APDs require a very stable power supply system. To preserve the high energy resolution of the calorimeter, a stability of the bias voltage of the order of 10^-4 is required over several months, a typical interval between absolute calibrations of the full read-out chain with physics events. This paper describes the High Voltage power supply system developed for CMS ECAL and its performances as measured in laboratory tests and during test-beam operations of several modules of the calorimeter
Realism and Objectivism in Quantum Mechanics
The present study attempts to provide a consistent and coherent account of
what the world could be like, given the conceptual framework and results of
contemporary quantum theory. It is suggested that standard quantum mechanics
can, and indeed should, be understood as a realist theory within its domain of
application. It is pointed out, however, that a viable realist interpretation
of quantum theory requires the abandonment or radical revision of the classical
conception of physical reality and its traditional philosophical
presuppositions. It is argued, in this direction, that the conceptualization of
the nature of reality, as arising out of our most basic physical theory, calls
for a kind of contextual realism. Within the domain of quantum mechanics,
knowledge of 'reality in itself', 'the real such as it truly is' independent of
the way it is contextualized, is impossible in principle. In this connection,
the meaning of objectivity in quantum mechanics is analyzed, whilst the
important question concerning the nature of quantum objects is explored.Comment: 20 pages. arXiv admin note: substantial text overlap with
arXiv:0811.3696, arXiv:quant-ph/0502099, arXiv:0904.2702, arXiv:0904.2859,
arXiv:0905.013
Platelet-lysate-Expanded Mesenchymal Stromal Cells as a Salvage Therapy for Severe Resistant Graft-versus-Host Disease in a Pediatric Population
Despite advances in graft-versus-host-disease (GVHD) treatment, it is estimated that overall survival (OS) at 2 years for hematopoietic cell transplantation (HCT) recipients who experience steroid-resistant GVHD is 10%. Among recent therapeutic approaches for GVHD treatment, mesenchymal stromal cells (MSCs) hold a key position. We describe a multicenter experience of 11 pediatric patients diagnosed with acute or chronic GVHD (aGVHD, cGVHD) treated for compassionate use with GMP-grade unrelated HLA-disparate donors' bone marrow-derived MSCs, expanded in platelet-lysate (PL)-containing medium. Eleven patients (aged 4-15 years) received intravenous (i.v.) MSCs for aGVHD or cGVHD, which was resistant to multiple lines of immunosuppression. The median dose was 1.2 × 10 6 /kg (range: 0.7-3.7 × 10 6 /kg). No acute side effects were observed, and no late side effects were reported at a median follow-up of 8 months (range: 4-18 months). Overall response was obtained in 71.4% of patients, with complete response in 23.8% of cases. None of our patients presented GVHD progression upon MSC administration, but 4 patients presented GVHD recurrence 2 to 5 months after infusion. Two patients developed chronic limited GVHD. This study underlines the safety of PL-expanded MSC use in children. MSC efficacy seems to be greater in aGVHD than in cGVHD, even after failure of multiple lines of immunosuppression
Calorimetry Task Force Report
In this note we summarize the studies and recommendations of the calorimeter simulation task force (CaloTF). The CaloTF was established in February 2008 in order to understand and reconcile the discrepancies observed between the CMS calorimetry simulation and the test beam data recorded during 2004 and 2006. As the result of studies by the CaloTF a new version of Geant4 was developed and introduced in the CMS detector simulation leading to significanly better agreement with test beam data. Fast and flexible parameterizations describing showering in the calorimeter are introduced both in the Full Simulation (with a Gflash-like approach) and in the Fast Simulation. The CaloTF has developed a strategy to rapidly tune the CMS calorimeter simulation using the first LHC collision data when it becomes available. The improvements delivered by the CaloTF have been implemented in the software release CMSSW 2.1.0
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