223 research outputs found
QCD Analysis of Polarized Deep Inelastic Data and Parton Distributions
A QCD analysis of the world data on polarized deep inelastic scattering is
presented in leading and next-to-leading order. New parameterizations are
derived for the quark and gluon distributions for the kinematic range x
\epsilon [10^{-9},1], Q^2 \epsilon [1,10^6] \GeV^2. The extrapolation far
outside the domain of the current measurements is given both to allow for
applications at higher values of and to be able to calculate integral
properties of the present distributions. The values of and
are determined. Emphasis is put on the derivation of the fully
correlated error bands for these distributions, which are also given
in terms of parameterizations and are directly applicable to determine
experimental errors of other polarized observables. The impact of the variation
of both the renormalization and factorization scales on the value of
is studied. Finally we perform a factorization--scheme invariant QCD analysis
based on the observables and in
next-to-leading order, which is compared to the standard analysis. A series of
low moments of parton densities, accounting for error correlation, are given to
allow for comparison with results from lattice simulations.Comment: 43 pages LATEX, 1 style files, 13 eps-figures, final version, Nucl.
Phys. B in prin
HARD PROBES OF DENSE MATTER
Direct probes for the QGP must be hard enough to resolve sub-hadronic scales
(\ll \la^{-1}) and distinguish confined and deconfined media. This can be
achieved by fast colour charges (jets) and heavy quark resonances (quarkonia).
After a general survey, we study quarkonia as confinement probe and show in
particular that confined matter is transparent, deconfined matter opaque to
\J's.Comment: 13 pages, plain TeX, figures available upon request from the autho
Introduction: building the history of language learning and teaching (HoLLT)
The papers presented in this issue are the result of a workshop held at the University of Nottingham in December 2012 as part of an Arts and Humanities Research Council research network Towards a History of Modern Foreign Language Teaching and Learning (2012â14) intended to stimulate historical research into language teaching and learning. This, the first workshop in the programme, focused on exchanging information on the history of language learning and teaching (HoLLT) across the different language traditions, for it had become clear to us that scholars working within their own language disciplines were often relatively unaware of work outside these. We hope that this special issue â with overview articles on the history of English, French, German, and Spanish as second/foreign languages â will help overcome that lack of awareness and facilitate further research collaboration. Charting the history of language teaching and learning will, in turn, make us all better informed in facing challenges and changes to policy and practice now and in the future. It is instructive in the current climate, for example, to realize that grave doubts were held about whether second foreign languages could survive alongside French in British schools in the early twentieth century (McLelland, forthcoming), or to look back at earlier attempts to establish foreign languages in primary schools (Bayley, 1989; Burstall et al., 1974; Hoy, 1977). As we write, language learning in England is undergoing yet more radical change. Language teaching for all children from the age of seven is being made compulsory in primary schools from 2014, while at Key Stage 3 (up to age 16), where a foreign language has not been compulsory since 2002, the most recent programme of study for England has virtually abandoned the recent focus on intercultural competence and now requires learners to âread great literature in the original languageâ,1 a radical change in emphasis compared to the previous half-century, which seems to reflect a very different view of what language learning is for. We seem to be little closer in 2014 than we were at the dawn of the twentieth century to answering with any certainty the questions that lie at the very foundations of language teaching: who should learn a foreign language, why learners learn, what they need to learn, and what we want to teach them â answers that we need before we can consider how we want to teach. The research programme begun under our research network is intended to help us to take âthe long viewâ on such questions
A highly specific and sensitive serological assay detects SARSâCoVâ2 antibody levels in COVIDâ19 patients that correlate with neutralization
Objective
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic challenges national health systems and the global economy. Monitoring of infection rates and seroprevalence can guide public health measures to combat the pandemic. This depends on reliable tests on active and former infections. Here, we set out to develop and validate a specific and sensitive enzyme linked immunosorbent assay (ELISA) for detection of anti SARS-CoV-2 antibody levels.
Methods
In our ELISA, we used SARS-CoV-2 receptor-binding domain (RBD) and a stabilized version of the spike (S) ectodomain as antigens. We assessed sera from patients infected with seasonal coronaviruses, SARS-CoV-2 and controls. We determined and monitored IgM-, IgA- and IgG-antibody responses towards these antigens. In addition, for a panel of 22 sera, virus neutralization and ELISA parameters were measured and correlated.
Results
The RBD-based ELISA detected SARS-CoV-2-directed antibodies, did not cross-react with seasonal coronavirus antibodies and correlated with virus neutralization (R2 = 0.89). Seroconversion started at 5 days after symptom onset and led to robust antibody levels at 10 days after symptom onset. We demonstrate high specificity (99.3%; N = 1000) and sensitivity (92% for IgA, 96% for IgG and 98% for IgM; > 10 days after PCR-proven infection; N = 53) in serum.
Conclusions
With the described RBD-based ELISA protocol, we provide a reliable test for seroepidemiological surveys. Due to high specificity and strong correlation with virus neutralization, the RBD ELISA holds great potential to become a
preferred tool to assess thresholds of protective immunity after infection and vaccination
DreiĂig Jahre FakultĂ€t Sprach- und Literaturwissenschaften an der Otto-Friedrich-UniversitĂ€t Bamberg (1977 bis 2007)
Anlass zur Vorlage der Festschrift ist das dreiĂigjĂ€hrige Bestehen der FakultĂ€t Sprach- und Literaturwissenschaften (SpLit) der Otto-Friedrich-UniversitĂ€t Bamberg (1977â2007). Sie soll die Entwicklung, die die FakultĂ€t seit ihrer GrĂŒndung genommen hat, möglichst knapp und sachlich dokumentieren. Sie hat daher den Charakter einer Leistungsbilanz, sie bietet streckenweise Materialien zu einer Chronik der FakultĂ€t, sie verschweigt aber auch nicht ihre âGeburtsfehlerâ in Gestalt mangelnder Ressourcen. In einer Zeit des Umbruchs, nĂ€mlich der bevorstehenden Verschmelzung mit der FakultĂ€t Geschichts- und Geowissenschaften (GGeo) zu einer FakultĂ€t Geistes- und Kulturwissenschaften (GuK), soll diese Selbstdarstellung der FakultĂ€t ihr Profil und ihre IdentitĂ€t bis zu ihrer zum 1.10.2007 zu Ende gegangenen selbstĂ€ndigen Existenz erkennbar machen.
Die Druckauflage wurde vom Dekanat der FakultÀt herausgegeben
The neutron and its role in cosmology and particle physics
Experiments with cold and ultracold neutrons have reached a level of
precision such that problems far beyond the scale of the present Standard Model
of particle physics become accessible to experimental investigation. Due to the
close links between particle physics and cosmology, these studies also permit a
deep look into the very first instances of our universe. First addressed in
this article, both in theory and experiment, is the problem of baryogenesis ...
The question how baryogenesis could have happened is open to experimental
tests, and it turns out that this problem can be curbed by the very stringent
limits on an electric dipole moment of the neutron, a quantity that also has
deep implications for particle physics. Then we discuss the recent spectacular
observation of neutron quantization in the earth's gravitational field and of
resonance transitions between such gravitational energy states. These
measurements, together with new evaluations of neutron scattering data, set new
constraints on deviations from Newton's gravitational law at the picometer
scale. Such deviations are predicted in modern theories with extra-dimensions
that propose unification of the Planck scale with the scale of the Standard
Model ... Another main topic is the weak-interaction parameters in various
fields of physics and astrophysics that must all be derived from measured
neutron decay data. Up to now, about 10 different neutron decay observables
have been measured, much more than needed in the electroweak Standard Model.
This allows various precise tests for new physics beyond the Standard Model,
competing with or surpassing similar tests at high-energy. The review ends with
a discussion of neutron and nuclear data required in the synthesis of the
elements during the "first three minutes" and later on in stellar
nucleosynthesis.Comment: 91 pages, 30 figures, accepted by Reviews of Modern Physic
Be careful with âKiezdeutschâ
Der Beitrag befasst sich mit Publikationen der Potsdamer Germanistin Heike Wiese ĂŒber eine Erscheinungsform des Deutschen, die bei Jugendlichen aus Zuwandererfamilien in groĂen StĂ€dten beobachtet wurde. Sie nennt sie âKiezdeutschâ. Der Beitrag problematisiert die Erhebungsmethodik, die linguistische Einordnung des âKiezdeutschenâ als Dialekt sowie die Geschichtsblindheit des Ansatzes. Denn MischvarietĂ€ten des Deutschen, die auf Sprachkontakten beruhen, gab es schon immer, und seit dem 18. Jahrhundert sind sie quellenmĂ€Ăig belegt. Die Literatur zum âKiezdeutschenâ wird als politisch und sozialpĂ€dagogisch motiviert und linguistisch unerheblich beurteilt.The article deals with publications of the Potsdam professor of Germanic linguistics Heike Wiese on so-called âKiezdeutschâ. Kiezdeutsch is a manifestation of contemporary German, observed in the speech and behaviour of teenage migrants in big cities. The contribution queries the methods of data acquisition, the classification of âKiezdeutschâ as a German dialect, and the absence of historical awareness. Mixed varieties of German as a result of language contacts have been present extant since the early Middle Ages and evidenced in texts from the 18th century on. The publications on âKiezdeutschâ are motivated mainly by political and social-educational points of view and can be assessed as linguistically irrelevant
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