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  • 1
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    Non-invasive imaging methods applied to neo- and paleontological cephalopod research (2014)
    Details
    Publication Date: 2022-07-19
    Description: Several non-invasive methods are common practice in natural sciences today. Here we present how they can be applied and contribute to current topics in cephalopod (paleo-) biology. Different methods will be compared in terms of time necessary to acquire the data, amount of data, accuracy/resolution, minimum/maximum size of objects that can be studied, the degree of post-processing needed and availability. The main application of the methods is seen in morphometry and volumetry of cephalopod shells. In particular we present a method for precise buoyancy calculation. Therefore, cephalopod shells were scanned together with different reference bodies, an approach developed in medical sciences. It is necessary to know the volume of the reference bodies, which should have similar absorption properties like the object of interest. Exact volumes can be obtained from surface scanning. Depending on the dimensions of the study object different computed tomography techniques were applied.
    Language: English
    Type: article , doc-type:article
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    OPUS
  • 2
    Electronic Resource
    Electronic Resource
    Suicide and mental health problems among Swedish youth in the wake of the 1990s recession (2000)
    Oxford, UK and Boston, USA : Blackwell Publishers Ltd
    International journal of social welfare 9 (2000), S. 0 
    Details
    ISSN: 1468-2397
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Sociology
    Notes: The purpose of this explorative study is to bring together a variety of Swedish data sources with indicators of youth mental health and living conditions in order to illuminate trends during the last decades, elucidate possible determinants of mental ill health and develop hypotheses to explain the observed trend patterns. The analyses in the study reveal some surprising inconsistencies with respect to the mental health trends among young people during the 1990s. Most striking is the pattern of increasing youth unemployment coinciding with almost inverse trends in the rates of suicide. The secular trends in fatal suicides during this period do not show any increase but some actual decrease in sub-populations despite high sustained levels of unemployment. In contrast, survey data indicate that the general mental health of youth during this period appears to have deteriorated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/1468-2397.00130
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Autonomic healing of polymer composites (2001)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 409 (2001), S. 794-797 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Structural polymers are susceptible to damage in the form of cracks, which form deep within the structure where detection is difficult and repair is almost impossible. Cracking leads to mechanical degradation of fibre-reinforced polymer composites; in microelectronic polymeric components it can ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/35057232
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Multimodality therapy in inflammatory breast cancer: Is there a place for surgery? (2000)
    Springer
    Annals of oncology 11 (2000), S. 1147-1153 
    Details
    ISSN: 1569-8041
    Keywords: breast ; cancer ; inflammatory ; multimodality ; surgery ; therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background:In many centres surgery is used as part of a combinedmodality approach to the treatment of inflammatory breast cancer (IBC).Nevertheless, its value is controversial given the high risk of metastaticrelapse and poor overall prognosis. We have reviewed patients with true IBCprospectively treated at the Royal Marsden Hospital in chemotherapy trials toassess further the role of surgery as part of combined modality treatment. Patients and methods:Fifty-four patients who had responsive orstable disease to primary chemotherapy went on to have either radiotherapyalone (n = 35) or surgery plus radiotherapy (n = 19); thedecision on surgery was based partly on clinician preference and partly onclinical response. Results:The 35 patients undergoing radiotherapy alone had amedian progression-free survival (PFS) of 16 months and median overallsurvival (OS) of 35 months. Twenty-four patients (69%) have relapsedwith a total of twelve (34%) relapsing locally. In comparison, the 19patients receiving both surgery and radiotherapy had a PFS of 20 months, anda median OS of 35 months. Fifteen patients (79%) have relapsed, eight(42%) of these locally. None of these differences were statisticallysignificant. Conclusions:These results do not suggest a clinical advantage forsurgery in addition to chemotherapy and radiotherapy for patients with IBC.They support the need for a prospective randomised trial to address thisquestion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008374931854
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Modal gain and lasing states in InAs/GaAs self-organized quantum dot lasers (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 615-617 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The modal gain of an InAs/GaAs self-organized quantum dot laser is determined from a measurement of the normal incidence, interband photocurrent. The maximum modal gain of the ground state transition is shown to have a value of (7±3) cm−1, considerably smaller than typical values for comparable quantum well lasers. The photocurrent technique is demonstrated to be a convenient and simple method for determining the spectral form of the gain and for comparing the modal gain of different devices. The consequences of the small modal gain for the laser characteristics are discussed. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371908
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Reduction of islands in full-pressure stellarator equilibria (2001)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 8 (2001), S. 3377-3381 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The control of magnetic islands is a crucial issue in designing stellarators. Islands are associated with resonant radial magnetic fields at rational rotational-transform surfaces and can lead to chaos and poor plasma confinement. In this article it is shown that variations in the resonant fields of a full pressure stellarator equilibrium can be related to variations in the boundary via a coupling matrix, and that inversion of this matrix determines a boundary modification for which the island content is significantly reduced. The numerical procedure is described and the results of island optimization are presented. Equilibria with islands are computed using the Princeton Iterative Equilibrium Solver, and resonant radial fields are calculated via construction of quadratic-flux-minimizing surfaces. A design candidate for the National Compact Stellarator Experiment [A. Reimann, L. Ku, D. Monticello et al., Phys. Plasmas 8, 2083 (2001)], which has a large island, is used to illustrate the technique. Small variations in the boundary shape are used to reduce island size and to reverse the phase of a major island chain. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1377614
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Production of enhanced pressure regions due to inhomogeneities in inertial confinement fusion targets : The 41st annual meeting of the division of plasma physics of the american physical society (2000)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 7 (2000), S. 2007-2013 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: It is shown that regions of enhanced pressure have been produced in targets with indirect radiation drive in planar and cylindrically convergent geometry through the interaction between the flows caused by target inhomogeneities and the main target drive. Design calculations for National Ignition Facility (NIF) [J. A. Paisner et al., Laser Focus World 30, 75 (1994)] targets with beryllium ablators formed by bonded hemi-shells [D. C. Wilson et al., Bull. Am. Phys. Soc. 43, 1667 (1998)] indicate that related behavior produces a seed perturbation in the ablator which can in some cases lead to the suppression of ignition. From simulation and analysis of the NIF problem in the planar geometry analog, a scaling for the perturbation, which should be useful for validation of the behavior with lower energy drive and smaller-scale geometries, is derived. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.874022
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    Paper (German National Licenses)
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  • 8
    Electronic Resource
    Electronic Resource
    Nanoscale limited area growth of InAs islands on GaAs(001) by molecular beam epitaxy (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 3282-3288 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Growth of InAs islands on a GaAs(001) substrate patterned with ∼50–200-nm diameter holes in an SiO2 mask overlayer providing selective GaAs nucleation areas is reported. The nanoscale pattern was generated in the SiO2 film by large-area interferometric lithography and dry etching. Two-dimensional, 285-nm period, arrays of InAs islands having heights of 10–15 nm with three different bottom diameters of 50–100, ∼150, and ∼200 nm were selectively grown on SiO2 patterned substrates by molecular beam epitaxy. Growth conditions were chosen to provide a very-low sticking coefficient of In atoms on the SiO2 surface suppressing volume contribution from migration of In atoms incident on the SiO2 mask region to nearby open GaAs surface areas. Formation of spherical-section InAs dots with diameters of about 50 nm relying on nanoscale-limited area growth is demonstrated. As the diameter of the hole increases beyond 150 nm, InAs islands deviate from a spherical section and self-assembled quantum dots confined within the open GaAs surface appear. A relation between dot formation and the nanoscale growth area is proposed, with a transition from single- to multiple-dot formation occurring at hole diameters of ∼100–150 nm. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1436303
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    Paper (German National Licenses)
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  • 9
    Electronic Resource
    Electronic Resource
    Fundamental relationship of excitonic photoluminescence intensity with excitation density in semiconductor quantum well structures (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 4075-4078 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The fundamental relationship between excitonic photoluminescence (PL) intensity and excitation intensity in semiconductor quantum well structures is developed. This relationship is further simplified in the regime of low excitation, and used for a fit function of the Arrhenius plot of time-integrated PL intensity. The proposed four fit parameters are definitely correlated to the distinct characteristic quantities of the sample material, which are the binding energy of excitons, the activation energy, the scattering time, and the background concentration in the well. The validity of the model has been confirmed using our experiments. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1290708
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    Photoluminescence from polymer-like hydrogenated and nitrogenated amorphous carbon films (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 5175-5179 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The mechanism of photoluminescence (PL) in hydrogenated amorphous carbon (a-C:H), and nitrogenated and hydrogenated amorphous carbon (a-C:H:N) thin films grown by radio frequency driven plasma enhanced chemical vapor deposition is still a subject of much debate. In this work, we investigate the PL signal obtained from a-C:H and a-C:H:N films, paying particular attention to the effect of nitrogen flow rate during growth, and postgrowth, ex situ annealing on the PL properties of the films. We also correlate the PL spectra to the electronic structure of the films. The films had a low paramagnetic defect density (1017 cm−3). The PL spectra were obtained using the 488 nm (2.54 eV) line of an argon ion laser, as the excitation source. It was observed that the nitrogenation of the films leads to the creation of new bands in the PL signal, which were correlated to the bond fraction of CN triple bonds, as measured by infrared spectroscopy. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1314620
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