42 research outputs found
Spectroscopy on a single trapped 137Ba+ ion for nuclear magnetic octupole moment determination
We present precision measurements of the hyperfine intervals in the 5D3/2
manifold of a single trapped Barium ion, 137 Ba+ . Measurements of the
hyperfine intervals are made between mF = 0 sublevels over a range of magnetic
fields allowing us to interpolate to the zero field values with an accuracy
below a few Hz, an improvement on previous measurements by three orders of
magnitude. Our results, in conjunction with theoretical calculations, provide a
30-fold reduction in the uncertainty of the magnetic dipole (A) and electric
quadrupole (B) hyperfine constants. In addition, we obtain the magnetic
octupole constant (C) with an accuracy below 0.1 Hz. This gives a subsequent
determination of the nuclear magnetic octupole moment, {\Omega}, with an
uncertainty of 1% limited almost completely by the accuracy of theoretical
calculations. This constitutes the first observation of the octupole moment in
137 Ba+ and the most accurately determined octupole moment to date.Comment: 4 pages, 3 figure
Nuclear Charge Radii of Be-7,9,10 and the one-neutron halo nucleus Be-11
Nuclear charge radii of Be have been determined by
high-precision laser spectroscopy. On-line measurements were performed with
collinear laser spectroscopy in the transition on a
beam of Be ions. Collinear and anticollinear laser beams were used
simultaneously and the absolute frequency determination using a frequency comb
yielded an accuracy in the isotope-shift measurements of about
1 MHz. Combination with accurate calculations of the mass-dependent isotope
shifts yield nuclear charge radii. The charge radius decreases from Be to
Be and then increases for the halo nucleus Be. When comparing our
results with predictions of {\it ab initio} nuclear structure calculations we
find good agreement. Additionally, the nuclear magnetic moment of Be was
determined to be and that of Be from a previous
-NMR measurement was confirmed.Comment: 4 pages, 2 figures calculated mass shift values have been
re-evaluated with the latest mass values for the beryllium isotopes and the
nuclear polarization contribution for Be-11, published by K. Pachucki et al.
ater submission of our manuscript, is also included no
Medical ontologies: the end of MeSH
Since the beginning of information technology the complexicity of medical questions and medical information management is an important topic which challenges computer scientists.In the eighties of last century artificial intelligence went awry. Though some core ideas of AI have brought up fruitful results. After all congruent development in a number of different scientific disciplines and the exponential development in computer hardware could meet the high requirements in medical information search. In 2000 Tim Berners-Lee's programmatic request for a Semantic Web gained the ontology topic broader attention.Already 20 years ago NLM started to develop the Unified Medical Language System (UMLS). So in medicine (PubMed) ontology integrated into a semantic net is in operation. Hence it is high time for medical librarians and documentalists to get into this topic although it is covered by a smoke screen of terminology from IT. Ontologies can be understood as tools for classification. So essential contributions from library and documentation science could be expected.This paper should open an entrance to the topic. It will explain fundamental elements of UMLS and includes an annotated list of literature for further studies.Die Komplexizität medizinischer Fragestellungen und des medizinischen Informationsmanagements war seit den Anfängen der Informatik immer ein besonders wichtiges Thema. Trotz des Scheiterns der Künstlichen Intelligenz in den 80er Jahren des vorigen Jahrhunderts haben deren Kernideen Früchte getragen. Durch kongruente Entwicklung einer Reihe anderer Wissenschaftsdisziplinen und der exponentiellen Entwicklung im Bereich Computerhardware konnten die gestellten, hohen Anforderungen bei der medizinischen Informationssuche doch noch erfüllt werden. Die programmatische Forderung von Tim Berners-Lee betreffend "Semantic Web" im Jahr 2000 hat dem Thema Ontologien für maschinenlesbare Repositorien in Allgemein- und Fachsprache breitere Aufmerksamkeit gewonnen. Da in der Medizin (PubMed) mit dem von NLM schon vor 20 Jahren entwickelten Unified Medical Language System (UMLS) eine funktionierende Ontologie in Form eines semantischen Netzes in Betrieb ist, ist es auch für Medizinbibliothekare und Medizindokumentare hoch an der Zeit, sich damit zu beschäftigen. Ontologien können im Wesen, trotz der informatisch vernebelnden Terminologie, als Werkzeuge der Klassifikation verstanden werden. Hier sind von seiten der Bibliotheks- und Dokumentationswissenschaft wesentliche Beiträge möglich. Der vorliegende Bericht bietet einen Einstieg in das Thema, erklärt wesentliche Elemente des UMLS und schließt mit einer kommentierten Anmerkungs- und Literaturliste für die weitere Beschäftigung mit Ontologien
Academic dishonesty, personality traits and academic adjustment
Many recent studies has been indicating that academic
dishonesty is more frequent in higher education, under the form plagiarism,
cheating on exams, and copying assignments from other students. The present research aims to explore the relationship of personality traits, academic dishonesty and academic adjustment. The results showed that conscientiousness, honesty and openness were significantly negatively related to reports of academic dishonesty. Academic neuroticism was the most powerful predictor of cheating behaviours, while an overall high level of maladjustment predicted the positive attitudes towards academic cheating. The significant associations between academic adjustment and academic dishonesty confirmed previous research in the field