558 research outputs found
Quality Control of Offshore Positioning Surveys
This paper discusses the need for a quality control method for offshore positioning surveys and then its actual use. It limits the discussion to radio locationing systems only, but this restriction does not imply that Satellite Navigation or Underwater Acoustic Positioning Systems do not require such quality control. The subject is divided into two parts. Firstly the calibration methods necessary to determine the zero/delay settings for the survey equipment and to establish the propagation velocity required in the survey. Secondly, the positioning of the survey vessel with the necessary, but often missing, â simultaneous quality controlâ of this positioning. The methods described in this paper are compared with field results, from which can be seen the often limited value of the most commonly used, and sometimes time-consuming and expensive, calibration methods. It will be shown here that the generally accepted principle of the location offshore of vessels and structures using only two position lines not only lacks reliability but can often result in costly resurveys. The lack of data redundancy in offshore surveys stands in sharp contrast to the practice in land surveying where data redundancy in observation and control surveys is common practice. With the increasing practice of having extra positioning equipment on stand-byâ especially in remote areasâ and with the increase in cost of offshore surveys, Shellâs Topographic Survey Department has developed a method based on redundancy of data. This method provides a continuous quality control of the offshore positioning while surveying, and avoids unpleasant surprises after the survey vessel has left the area
Zorgen rondom IVF
De vraag naar dit onderzoek kwam vanuit de patiëntenvereniging Freya terecht bij de Wetenschapswinkel Geneeskunde en Volksgezondheid van de Rijksuniversiteit Groningen.
Deze vraag is vertaald in een wetenschappelijk te beantwoorden probleemstelling. Het onderzoek dat hieruit is voort gekomen, is uitgevoerd in het kader van een afstudeeronderzoek.
De probleemstelling van het onderzoek luidt:
In welke opzichten en in hoeverre hebben vrouwen die kiezen voor IVF (in vitro fertilisatie), behoefte aan steun en begeleiding bij keuzen en ervaringen die zich in het behandelingstraject voordoen...
The Small-x Evolution of Unpolarized and Polarized Structure Functions
A brief overview is presented of recent developments concerning resummed
small-x evolution, based upon the renormalization group equation. The
non-singlet and singlet structure functions are discussed for both polarized
and unpolarized deep-inelastic scattering. Quantitative results are displayed
and uncertainties from uncalculated subleading terms are discussed.Comment: 9 pages with 5 EPS figures. To appear in Acta Physica Polonic
Deep-inelastic production of heavy quarks
Deep-inelastic production of heavy quarks at HERA, especially charm, is an
excellent signal to measure the gluon distribution in the proton at small
values. By measuring various differential distributions of the heavy quarks
this reaction permits additional more incisive QCD analyses due to the many
scales present. Furthermore, the relatively small mass of the charm quark,
compared to the typical momentum transfer , allows one to study whether and
when to treat this quark as a parton. This reaction therefore sheds light on
some of the most fundamental aspects of perturbative QCD. We discuss the above
issues and review the feasibility of their experimental investigation in the
light of a large integrated luminosity.Comment: 10 pages, uses epsfig.sty, five ps figures included. To appear in the
proceedings of the workshop Future Physics at HERA, eds. G. Ingelman, A. De
Roeck and R. Klanner, DESY, Hamburg, 199
Maternal separation induces anhedonia in female heterozygous serotonin transporter knockout rats
Funding Information: Funding was received from the NARSAD young investigator grant from the Brain & Behavioural Research foundation (grant nr 25206 ) and from the European Unionâs Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 660152 .Peer reviewe
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