1,591 research outputs found
Moments of the Virtual Photon Structure Function
The photon structure function is a useful testing ground for QCD. It is
perturbatively computable apart from a contribution from what is usually called
the hadronic component of the photon. There have been many proposals for this
nonperturbative part of the real photon structure function. By studying moments
of the virtual photon structure function, we explore the extent to which these
proposed nonperturbative contributions can be identified experimentally.Comment: LaTeX, 16 pages + 14 compressed and uuencoded postscript figures,
UMN-TH-1111/9
A quantitative theory-versus-experiment comparison for the intense laser dissociation of H2+
A detailed theory-versus-experiment comparison is worked out for H
intense laser dissociation, based on angularly resolved photodissociation
spectra recently recorded in H.Figger's group. As opposite to other
experimental setups, it is an electric discharge (and not an optical
excitation) that prepares the molecular ion, with the advantage for the
theoretical approach, to neglect without lost of accuracy, the otherwise
important ionization-dissociation competition. Abel transformation relates the
dissociation probability starting from a single ro-vibrational state, to the
probability of observing a hydrogen atom at a given pixel of the detector
plate. Some statistics on initial ro-vibrational distributions, together with a
spatial averaging over laser focus area, lead to photofragments kinetic
spectra, with well separated peaks attributed to single vibrational levels. An
excellent theory-versus-experiment agreement is reached not only for the
kinetic spectra, but also for the angular distributions of fragments
originating from two different vibrational levels resulting into more or less
alignment. Some characteristic features can be interpreted in terms of basic
mechanisms such as bond softening or vibrational trapping.Comment: submitted to PRA on 21.05.200
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YMP Engineered Barrier Systems Scaled Ventilation Testing
Yucca Mountain, approximately 100 miles northwest of Las Vegas, Nevada, has been selected as the site for the nation's first geologic repository for high level nuclear waste. The Yucca Mountain Project (YMP) is currently developing the design for the underground facilities. Ventilation is a key component of the design as a way to maintain the desired thermal conditions in the emplacement drifts prior to closure. As a means of determining the effects of continuous ventilation on heat removal from the emplacement drifts two series of scaled ventilation tests have been performed. Both test series were performed in the DOE/North Las Vegas Atlas facility. The tests provided scaled (nominally 25% of the full scale emplacement drift design) thermal and flow process data that will be used to validate YMP heat and mass transport codes. The Phase I Ventilation Test series evaluated the ability of ambient ventilation air to remove energy under varying flow and input power conditions. The Phase II Ventilation Test series evaluated the ability of pre-conditioned ventilation air to remove energy under varying flow, input temperature and moisture content, and simulated waste package input power conditions. Twenty-two distinct ventilation tests were run
Sulphur monoxide emission tracing an embedded planet in the HD 100546 protoplanetary disk
Stars and planetary system
Unveiling the outer dust disc of TW Hya with deep ALMA observations
Stars and planetary system
Protocol of a randomised trial of teriparatide followed by zoledronic acid to reduce fracture risk in adults with osteogenesis imperfecta
Introduction: Osteogenesis imperfecta (OI) is a rare genetic disease associated with multiple fractures throughout life. It is often treated with osteoporosis medications but their effectiveness at preventing fractures is unknown. The Treatment of Osteogenesis Imperfecta with Parathyroid Hormone and Zoledronic Acid trial will determine if therapy with teriparatide (TPTD) followed by zoledronic acid (ZA) can reduce the risk of clinical fractures in OI.
Methods and analysis: Individuals aged ≥18 years with a clinical diagnosis of OI are eligible to take part. At baseline, participants will undergo a spine X-ray, and have bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) at the spine and hip. Information on previous fractures and previous bone targeted treatments will be collected. Questionnaires will be completed to assess pain and other aspects of health-related quality of life (HRQoL). Participants will be randomised to receive a 2-year course of TPTD injections 20 µg daily followed by a single intravenous infusion of 5 mg ZA, or to receive standard care, which will exclude the use of bone anabolic drugs. Participants will be followed up annually, have a repeat DXA at 2 years and at the end of study. Spine X-rays will be repeated at the end of study. The duration of follow-up will range between 2 and 8 years. The primary endpoint will be new clinical fractures confirmed by X-ray or other imaging. Secondary endpoints will include participant reported fractures, BMD and changes in pain and HRQoL.
Ethics and dissemination: The study received ethical approval in December 2016. Following completion of the trial, a manuscript will be submitted to a peer-reviewed journal. The results will inform clinical practice by determining if TPTD/ZA can reduce the risk of fractures in OI compared with standard care.
Trial registration number: ISRCTN15313991
Religious Values, Practices and Pregnancy Outcomes: A Comparison of the Impact of Sect and Mainstream Christian Affiliation
In this report 6566 women enrolled in the Mater-University of Queensland Study of Pregnancy (MUSP) were separated into three groups; members of religious sects, Christians who attend church frequently and Christians who are infrequent attenders. These three groups, respectively labelled Christian sects, Christian attenders and lukewarm Christians were compared on a number of social background, lifestyle and pregnancy outcome variables. The sect members appeared to have the most favourable health, lifestyles and healthy babies at delivery, though this latter finding appears attributable to specific characteristics of the mother and her lifestyle. On most measures the children of lukewarm Christians appear to manifest the worst health while Christian attenders form a group whose children's health is between that of sect members and lukewarm Christians
Burgers' Flows as Markovian Diffusion Processes
We analyze the unforced and deterministically forced Burgers equation in the
framework of the (diffusive) interpolating dynamics that solves the so-called
Schr\"{o}dinger boundary data problem for the random matter transport. This
entails an exploration of the consistency conditions that allow to interpret
dispersion of passive contaminants in the Burgers flow as a Markovian diffusion
process. In general, the usage of a continuity equation , where stands for the
Burgers field and is the density of transported matter, is at variance
with the explicit diffusion scenario. Under these circumstances, we give a
complete characterisation of the diffusive transport that is governed by
Burgers velocity fields. The result extends both to the approximate description
of the transport driven by an incompressible fluid and to motions in an
infinitely compressible medium. Also, in conjunction with the Born statistical
postulate in quantum theory, it pertains to the probabilistic (diffusive)
counterpart of the Schr\"{o}dinger picture quantum dynamics.Comment: Latex fil
Four Lessons in Versatility or How Query Languages Adapt to the Web
Exposing not only human-centered information, but machine-processable data on the Web is one of the commonalities of recent Web trends. It has enabled a new kind of applications and businesses where the data is used in ways not foreseen by the data providers. Yet this exposition has fractured the Web into islands of data, each in different Web formats: Some providers choose XML, others RDF, again others JSON or OWL, for their data, even in similar domains. This fracturing stifles innovation as application builders have to cope not only with one Web stack (e.g., XML technology) but with several ones, each of considerable complexity. With Xcerpt we have developed a rule- and pattern based query language that aims to give shield application builders from much of this complexity: In a single query language XML and RDF data can be accessed, processed, combined, and re-published. Though the need for combined access to XML and RDF data has been recognized in previous work (including the W3C’s GRDDL), our approach differs in four main aspects: (1) We provide a single language (rather than two separate or embedded languages), thus minimizing the conceptual overhead of dealing with disparate data formats. (2) Both the declarative (logic-based) and the operational semantics are unified in that they apply for querying XML and RDF in the same way. (3) We show that the resulting query language can be implemented reusing traditional database technology, if desirable. Nevertheless, we also give a unified evaluation approach based on interval labelings of graphs that is at least as fast as existing approaches for tree-shaped XML data, yet provides linear time and space querying also for many RDF graphs. We believe that Web query languages are the right tool for declarative data access in Web applications and that Xcerpt is a significant step towards a more convenient, yet highly efficient data access in a “Web of Data”
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