Search Results - (Author, Cooperation:F. Roland)

2013-12-18

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Atmosphere/chemistry ; Brazil ; Carbon Cycle ; Carbon Dioxide/*analysis ; Lakes/chemistry ; Plants/metabolism ; Rivers/*chemistry ; Water Movements ; *Wetlands

2018-07-27

'Ein Fragebogen zur Erfassung individueller Differenzen im Engagement und der Freude bei Denkaufgaben wird vorgestellt. Die Skala stellt eine Übersetzung der 'Need for Cognition' (NFC)-Skala dar, die von Cacioppo & Petty (1982) für den anglo-amerikanischen Sprachbereich entwickelt wurde. Die deutsche Version der NFC-Skala erlaubt eine ökonomische Durchführung und weist gute Skalenkennwerte auf. Im Zuge des verstärkten Interesses an kognitiven Prozessen bietet sie die Möglichkeit, neben situativ bedingten auch dispositional bedingte Variationen in der Intensität der kognitiven Verarbeitung und deren Auswirkungen auf soziales Urteilen und Verhalten zu untersuchen.' (Autorenreferat)

Sozialwissenschaften, Soziologie ; Psychologie ; Social sciences, sociology, anthropology ; Psychology ; Social Psychology ; Methods and Techniques of Data Collection and Data Analysis, Statistical Methods, Computer Methods ; Erhebungstechniken und Analysetechniken der Sozialwissenschaften ; Sozialpsychologie ; cognition ; cognitive factors ; mental situation ; scale construction ; information collection ; personality ; motivation ; situation ; achievement ; involvement ; Motivation ; Leistung ; Kognition ; Engagement ; psychische Situation ; kognitive Faktoren ; Situation ; Informationsaufnahme ; Persönlichkeit ; Skalenkonstruktion ; Grundlagenforschung ; basic research

Arbeitspapier, working paper

article

2001

Institutionalisierung ; Lehre ; Aufsatz ; Geschichte (Histor) ; Professionalisierung ; Fachhochschule ; Studium ; Hochschullehrer ; Soziologie

Soziologie, (2001) H. 2, S. 16-39, 0340-918X

German

Tabellen 8, Übersichten 2

2018-12-13

Nature Publishing Group (NPG)

2045-2322

Natural Sciences in General

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

Chromium-doped forsterite single crystals grown under conditions that produce a high Cr4+/Cr3+ ratio were examined by electron paramagnetic resonance (EPR) at 9.6 and 34 GHz. The crystals were grown in 2–3 atm of oxygen by the floating-zone method starting from polycrystalline chromium-doped forsterite powder synthesized via a sol–gel method. Three crystals with chromium concentrations of 110, 300, and 390 ppm were studied. At 34 GHz, transitions are observed for the laser-active tetrahedral Cr4+ species that are not observable at 9.6 GHz, which improve the resolution and accuracy with which the magnetic parameters can be measured by EPR. In addition, peaks for a non-Kramers species appear at 34 GHz that were not observed at 9.6 GHz. These peaks are not analyzed in detail, but are tentatively ascribed to Cr4+ in the octahedral substitution sites of the crystal. At the highest chromium concentration, the Cr3+ spectra show evidence of direct interaction with Cr4+. A global least-squares fit of the combined 9.6 and 34 GHz data for the 300 ppm crystal gives D=64.26±0.18 GHz, E=−4.619±0.009 GHz, gx=1.955±0.009, gy=2.005±0.040, gz=1.965±0.006, and places the magnetic z axis in the ab plane at an angle of 43.8±0.3° from the b crystallographic axis (in Pbnm).A method for accurately measuring the Cr4+/Cr4+ ratio using EPR line intensities is given. The EPR linewidth of the Cr4+ center exhibits a strong orientation dependence that is well-modeled by including site variations in the D and E zero-field splittings and in the orientation of the z magnetic axis. The linewidth analysis reveals a high degree of correlation between the distributions in D and E, and a somewhat weaker correlation between E and the z axis orientation. These results are interpreted to suggest that the tetrahedral Cr4+ sites vary mainly in the degree of compression of the tetrahedral cage along the a crystallographic axis. The Cr4+ EPR linewidths increase significantly at higher chromium concentration, but maintain the same qualitative orientation dependence. The EPR data indicate that the major contribution to inhomogeneity in the tetrahedral site, which may be related to the tunable range of the Cr4+ laser center, is distortion induced by chromium substitution into the crystal lattice rather than direct chromium–chromium interactions.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The mapping of rotational isomeric state (RIS) models for chain molecules onto a high coordination lattice may permit efficient simulations of the self-assembly of block copolymers. Recently the second nearest neighbor diamond (2nnd) lattice was introduced for this purpose, and the RIS model for polyethylene was successfully mapped onto that lattice. Here the mapping procedure is extended to the two examples of poly (A–A–B) with A=CH2, B=O or S in order to ascertain whether the mapping can produce reasonable values for the mean square dipole moment, as well as the mean square end-to-end distance, and also to provide mapped RIS chains for construction of block copolymers. Simulations of single chains of polyoxyethylene (POE) and polythiaethylene have been performed on the 2nnd lattice by incorporating short range interactions through an extended RIS formalism. The overall dimensions of the chains, specifically of POE, are in agreement with the unperturbed dimensions of the classical RIS model. The characteristic ratio of the mean square dipole moments for long POE chains is close to the values reported in experiments and earlier RIS calculations. The ratio of the mean square radius of gyration for cyclic to acyclic POE chains of the same degree of polymerization approaches the long chain limit of 1/2. Simulations of single chains have also been performed in varying solvent environments, by implementing long range interactions via the lattice formulation of the second virial coefficient. As a result of these simulations, the strength of attractive and repulsive long range interactions on the 2nnd lattice can be determined for attaining theta solvent conditions. © 1996 American Institute of Physics.

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1440-1797

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Canadian aboriginal people experience end-stage renal disease at rates 2.5–4 times higher than those found in the general population. Up to 60% of cases are due to diabetic end-stage renal disease, while most of the remainder are caused by a variety of types of glomerulonephritis. The greatest increase in cases of end-stage renal disease among aboriginal people since 1981 has been observed in those with diabetes. There appear to be three major contributing influences to the increase in diabetic end-stage renal disease among Canadian aboriginal people. First, the rates of type 2 diabetes mellitus have increased from virtually zero to several times those seen in the general population in less than 60 years. Second, aboriginal people with diabetes have seven times the rate of diabetic end-stage renal disease compared with their non-aboriginal counterparts. Finally, birth rates among aboriginal people are higher than in any other segment of the population. An epidemic of diabetic end-stage renal disease is the most important nephrological issue facing Canadian aboriginal people and threatens to overwhelm health care resources in many parts of the country unless effective early recognition and prevention programmes are established.

Electronic Resource

0028-4866

English, American Studies

0304-4165

(Mitochondria) ; Ferritin ; Iron content ; Iron mobilization ; Species specificity

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Medicine

Physics

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] On the other hand, Kertes and Beck2 conclude a paper on the tributyl phosphate extraction of Tc(VII) with the dilemma: Consequently, the origin of the different extractabilities of HTcO4 and HReO4 found, lies in their different acid strengths and it follows that HReO4 is a stronger acid than HTcO4. ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Extensive digestion of ribonucleic acid from B. subtilis or yeast by ribonuclease results in a considerable or complete loss of inhibitory power. Dialysable fractions have been obtained which at concentrations of the order of 10~7 M reverse the inhibition by yeast ribonucleic acid completely. This ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Polyadenylic acid was synthesized by the action of polynucleotide phosphorylase prepared from Micrococcus lysodeikticus1. Contaminating protein was removed by the method of Sevag2. Formalin-treated polyadenylic acid was prepared by the method of Fraenkel-Conrat3. In Fig. 1 are shown the titration ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Fig.1 Fig. 2 In the first experiment (Fig. 1) 8 ml. of cells were mixed with 3 ml. of 0.1 M tris buffer and 5 ml. of 0.1 per cent lysozyme (Worthington crystalline enzyme). The suspension was incubated at 37 , and at periodic intervals 2 ml. aliquots were removed and added to 2 ml. of 5 per cent ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] The enzyme has been obtained in a partially purified and highly active form from aqueous extracts of lysed cells fractionated with ammonium sulphate at pH 8. The major portion of the activity is associated with the 30-40 per cent saturation fraction. The enzyme activity is determined by measuring ...

Electronic Resource

0014-5793

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

1572-9125

Springer Online Journal Archives 1860-2000

Mathematics

Abstract A nonlinear transformation whose domain is the class of Pringsheim convergent double series is introduced, defined, and studied for the purpose of accelerating the convergence of a double series. A number of theorems are established which enable one to make effective use of the transformation. In particular, special attention is given to the case in which the transformed series converges uniformly better than the original double series. Finally, several examples are given to illustrate the effectiveness of the transform.

Electronic Resource

0278-9671

History

Medicine

TOWARD A NEW DISCIPLINE

0162-0134

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Electronic Resource

1433-0385

Key words: Laparoscopic hernia repair (TAPP) ; Lichtenstein-procedure ; Tension-free inguinal hernia repair.

Springer Online Journal Archives 1860-2000

Medicine

Zusammenfassung. Im Rahmen einer prospektiven Beobachtungsstudie wurden im Zeitraum Juni 1992 bis Februar 1994 94 Patienten mit 100 Leistenhernien laparoskopisch (TAPP) und von März 1993 bis November 1994 100 Patienten mit 108 Leistenhernien offen mit einem Lichtenstein-Patch versorgt. In bezug auf Operationsdauer, postoperative Schmerzen und Komplikationen sowie Krankenstand wurden nur geringe Unterschiede festgestellt. Aufgrund der schwierig erlern- und lehrbaren Technik wurde die TAPP-Operation nur von einem Operateur, die Lichtenstein-Operation von allen 11 Mitarbeitern durchgeführt, was die Einfachheit des offenen Vorgehens demonstriert. Bislang zeichnet sich eine höhere Rezidivhäufigkeit für die TAPP-Gruppe (8 vs. 0) ab, wobei jedoch die Lernphase zu berücksichtigen ist. Die Lichtenstein-Operation ist in Lokalanaesthesie einfach auszuführen, leicht erlern- und lehrbar, sicher, effizient und kostensparend (DM 750,–) und deshalb der laparoskopischen Methode überlegen. Eine geplante randomisierte Studie wurde verworfen, laparoskopische Hernienreparationen werden in unserer Klinik seither nicht mehr durchgeführt.

Schlüsselwörter: Laparoskopische Hernienreparation (TAPP) – Lichtenstein-Operation – spannungsfreie Leistenbruchoperation.

Summary. In a prospective study, from June 1992 to February 1994 94 patients with 100 hernias were treated laparoscopically (TAPP) and from March 1993 to November 1994 100 patients with 108 hernias were treated with a Lichtenstein patch. Concerning duration of operation, postoperative outcome, complications and return to work, only minor differences were noted. Because of the more demanding and difficult technique, all TAPP procedures were performed by one surgeon, whereas all 11 surgeons of the department performed the Lichtenstein procedure without any learning curve, which demonstrates the simplicity of the procedure. A higher recurrence rate was found for the TAPP procedure (8 vs 0), however the learning curve has to be considered. The Lichtenstein operation is easy to learn and perform, safe, efficient, cheaper (750 DM) and therefore superior to the TAPP procedure. A planned randomized study was cancelled; laparoscopic hernia repair is no longer carried out in our department.

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