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2020-08-01

Wir beschäftigen uns in diesem Aufsatz mit Phänomenen netzgängiger Beziehungsinitiierung und der Relevanz von Dating-Apps im intersubjektiven Geschehen. Neben der skizzenhaften Aufarbeitung eines komplexen und ambivalenten Forschungsstandes stellen wir die Ergebnisse einer Interviewstudie mit Nutzer*innen solcher Apps vor. In der Auswertung des empirischen Materials, welches wir mithilfe der Grounded-Theory-Methodologie (GTM) realisierten, eröffnen wir Einblicke in technologisch vermittelte kommunikative Prozesse und arbeiten die (inter-)subjektive(n) Bedeutsamkeit(en) solcher Apps heraus.

This paper investigates the phenomenon of online dating, whereby the relevance of dating apps in intersubjective contexts are examined. In addition to the illustration of a complex but ambivalent state of research, the paper presents the results of an interview study. In the evaluation of the empirical material, which we realized with the help of Grounded Theory Methodology (GTM), we open up insights into specific, technologically mediated communicative practices and work out the (inter-)subjective significance of such apps.

Soziologie, Anthropologie ; Sociology & anthropology ; Online-Dating; Dating-Apps ; Wissenschaftssoziologie, Wissenschaftsforschung, Technikforschung, Techniksoziologie ; Sociology of Science, Sociology of Technology, Research on Science and Technology ; Grounded Theory ; Online-Medien ; soziale Beziehungen ; Initiation ; kommunikatives Handeln ; Mediatisierung ; grounded theory ; online media ; social relations ; initiation ; communicative action ; mediatization

Zeitschriftenartikel, journal article

1089-7550

AIP Digital Archive

Physics

Heteroepitaxial diamond films can be grown by bias enhanced nucleation on iridium buffer layers followed by an appropriate textured-growth step. Unlike epitaxial diamond films on silicon, the mosaicity reduction during textured growth includes tilt as well as twist. We conclude that different mechanisms causing the grain coarsening are working in the two cases. It is shown that the principle of evolutionary selection can be excluded as a decisive mechanism in the present films. Merging of neighboring grains by disclination formation yields an alternative explanation, that can convincingly substantiate the differences between the textured growth on iridium and silicon. From a Monte–Carlo type simulation describing the texture evolution due to merging of grains, a simple functional correlation between grain coarsening and mosaicity reduction is deduced. Comparison between simulation and experiment allows one to estimate the contributions of different processes. Finally, the general significance of the present findings for other materials is discussed. © 2002 American Institute of Physics.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The UHV-preparation and -characterization of thin, highly ordered polymer films of 2,5-distyrylpyrazine is reported. Monomer films were evaporated from a Knudsen cell. Subsequent photo-oligomerization occurs by illumination with UV light. The desorption behavior of the monomers and the lower oligomers was studied by temperature-programmed desorption mass spectrometry (TDS). The photoreaction was monitored in situ by high resolution electron energy loss spectroscopy (HREELS) in the range of electronic transitions. The information obtained from the loss spectra are compared to those from absorption and fluorescence spectroscopy. The results are discussed in the framework of the calculated electronic structure of related compounds.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The residual stress in thin diamond films with a strongly improved heteroepitaxial alignment has been studied by x-ray diffraction and micro-Raman spectroscopy. The measurements have been compared with the predictions from finite element simulations. The diamond films have been deposited by microwave plasma chemical vapor deposition at a temperature of 700°C on thin (200 nm) iridium buffer layers on SrTiO3(001). Three different regions have been found for a 600 nm thick diamond film: (I) a high quality epitaxial central area with 〉109 cm−2 oriented diamond grains showing a mosaic spread of only (approximate)1°; (II) a ringlike area of isolated epitaxial islands; and (III) a nontextured closed film at the edge of the sample. In area I the stress tensor was determined from the mean shift of the x-ray Bragg reflections. It can be interpreted in terms of a plane, biaxial stress state with σ=−4.9 GPa which is confirmed by micro-Raman measurements. Analyzing the diamond (004) and (311) peak profiles measured by x-ray diffraction (XRD) using monochromatic CuKα1 radiation allows us to distinguish a strongly shifted main component and a weaker, broader component with a minor shift. Finite element simulations predict a pronounced elastic relaxation of the thermal stress at rugged surfaces thus explaining this minor component. They also substantiate a stress reduction by more than 80% as observed by Raman measurements in area II. Combining all measurements taken in the different areas with the predictions of the simulation allows to separate four contributions, i.e., the thermal stress, elastic stress relaxation at a rugged surface, inhomogeneous stress contributions from the coalescence of the grains, and finally coherence stress due to lattice misfit. © 2000 American Institute of Physics.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

A novel method yielding simultaneous information about location and orientation of the crystallites in a polycrystalline specimen has been developed and succesfully applied to the investigation of thin diamond films deposited on silicon. The experiment uses the parallel beam from a synchrotron radiation source and a microchannel plate as collimator in front of an image plate detector. Exposure times of only a few minutes could be realized. The spatial resolution was 0.375 mm but can easily be improved. © 1995 American Institute of Physics.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

Imbedded thin-film thermocouples can be used for the measurement of transient surface temperatures with high spatial resolution and sensitivity. To minimize environmental effects it is desirable to have close proximity between the reference junction and the sensor junction. In this article, we present and compare two calibration techniques for such thermocouples. The first technique is a steady-state technique and uses a focused laser beam with a diameter of 3 μm as a point heat source. This technique consists of two steps. The first step is an absolute, but spatially averaged temperature measurement with a resistive temperature sensor. In the second step, the uncalibrated thermocouple junction is translated to resolve the spatial temperature profile generated by the laser spot. Both measurements are then combined to provide an absolute calibration which is independent of the thermal properties of the imbedding material and of the absorbed laser power. We used a simple sensor design which consists of a Ni resistive stripe, and the thermocouple junctions it forms with Ta/Au/Ta electrical leads. The second calibration technique is based on a dynamic measurement. To implement this technique we fabricated a small electrical heating element close to one of the junctions. With the dynamic calibration, the time-resolved response of the thermocouple to a short heat pulse is recorded. A least-squares fit of a simple model of heat diffusion to the measured response yields both the temperature calibration of the thermocouple and the heat diffusivity of the imbedding medium. The temperature calibration of the thermocouple obtained with the dynamic technique is in good agreement with the steady-state calibration.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Oriented diamond films have been grown on Si(001) and Si(111) substrates by microwave plasma chemical vapor deposition. X-ray diffractometry has been employed for pole figure measurements which have been evaluated by the component method. This technique can be applied to multiphase materials with overlapping pole figures. It decomposes the texture into components by identifying preferred directions in the pole density distribution. Thereby the textures of both diamond on Si(001) and on Si(111) have been reproduced quantitatively elucidating the heteroepitaxial orientational relationship and the occurrence of twinning. The volume fractions of both epitaxially oriented diamond crystallites and their twins of first order have been determined. It is shown that under the employed nucleation and growth conditions twinning is more pronounced for diamond on Si(111) than on Si(001). Furthermore, the fraction of randomly oriented crystallites in both textures has been determined. © 1995 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Very thin diamond films (thickness ∼0.1 μm) have been investigated by x-ray diffraction pole figure measurements using synchrotron radiation in order to understand the mechanism of heteroepitaxial diamond nucleation and the first steps of film growth on silicon(001) substrates. The diamond layers consist of an epitaxially aligned component with a crystallographic orientation identical to the substrate. The initial orientational spread of the grains around the perfect epitaxial orientation prior to any modification by a subsequent textured growth step has been determined. In the studied temperature range for the nucleation step the misalignment decreases slightly with increasing temperature. Besides the epitaxial crystallites their corresponding twins of first and second order have been found. The intensity distribution of the pole figures indicates that the process of twinning plays a dominating role in the initial growth stage which shows a tendency to become even more pronounced for higher substrate temperatures. © 1996 American Institute of Physics.

Electronic Resource

1467-9817

Blackwell Publishing Journal Backfiles 1879-2005

Linguistics and Literary Studies

Education

Student reading skills are below grade level in many schools and professionals are constantly searching for new ideas to enhance reading curricula. To address this problem in one elementary school, a parent/school reading programme was implemented. Parents were encouraged to increase the amount of time spent reading with their children at home and the school provided easily accessible reading materials, suggestions for encouraging reading at home, prizes and special activities. Programme participants demonstrated a higher increase in reading rate and accuracy than the matched peers. Prior to implementation and at the end of the reading programme, parents and students who chose to participate in the programme reported positive attitudes toward reading together. Implications of these results are discussed and an emphasis is placed on expanding research in the area.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

The lattice orientations near the interface of chemical vapor deposited diamond films on Si(001) have been studied by orientation imaging microscopy. This technique is based on the automated analysis of electron backscatter Kikuchi diffraction patterns. The electron beam has been scanned in discrete steps over the reverse side of the diamond film after having removed the substrate. The obtained data have allowed us to determine the texture and to visualize quantitatively the orientational arrangement of and among individual diamond crystallites in the near-interface region. A comparison with the orientation of the substrate has proved the existence of epitaxially nucleated grains. A high amount of twinned diamond has been deduced from the pole figures and verified by analysis of orientation correlations between neighboring crystallites. Moreover, the grain boundary maps have allowed us to monitor and quantify directly the occurring twin boundaries. © 1994 American Institue of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Heteroepitaxial diamond films with highly improved alignment have been realized by using the layer sequence diamond/Ir/SrTiO3(001). In a first step, epitaxial iridium films with a misorientation 〈0.2° have been deposited on polished SrTiO3(001) surfaces by electron-beam evaporation. Using the bias-enhanced nucleation procedure in microwave plasma chemical vapor deposition, epitaxial diamond grains with a density of 109 cm−2 could be nucleated on these substrates. The orientation relationship for this layer system is diamond(001)[100](parallel)Ir(001)[100](parallel)SrTiO3(001)[100]. The polar and azimuthal spread for the crystal orientation of a 600 nm thick diamond film is about 1° in each case. For an 8 μm thick diamond film a significantly improved alignment of 0.34° (polar) and 0.65° (azimuthal) has been measured. The latter values, which to the best of our knowledge are superior to those of all former reports about epitaxial diamond films on alternative substrates, indicate the high potential of the substrate Ir/SrTiO3 for the realization of large-area single-crystalline diamond films. © 1999 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

It is shown that diamond nucleation on iridium buffer layers followed by an appropriate textured-growth step offers a viable way to realize single-crystal diamond films. Bias-enhanced nucleation on iridium layers results in heteroepitaxial diamond films with highly improved alignment. By a subsequent textured-growth step, the mosaicity can be further reduced for tilt as well as for twist in sharp contrast to former experiments using silicon substrates. Minimum values of 0.17° and 0.38° have been measured for tilt and twist, respectively. Plan view transmission electron microscopy of these films shows that, for low thicknesses (0.6 μm and 8 μm), the films are polycrystalline, consisting of a closed network of grain boundaries. In contrast, at the highest thickness (34 μm) most of the remaining structural defects are concentrated in bands of limited extension. The absence of an interconnected network of grain boundaries shows that the latter films are no longer polycrystalline. © 2001 American Institute of Physics.

Electronic Resource

1467-9922

Blackwell Publishing Journal Backfiles 1879-2005

Linguistics and Literary Studies

Psychology

Some Cognitive Issues in Second Language Acquisition: A Review of Semantic and Conceptual Development: An Ontological Perspective by F. Kiel

Electronic Resource

1539-6924

Blackwell Publishing Journal Backfiles 1879-2005

Energy, Environment Protection, Nuclear Power Engineering

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The parameter space for the heteroepitaxial nucleation of diamond on Si(001) using the bias process was studied by x-ray diffraction texture measurements. It was found that heteroepitaxial orientation can be achieved over a wide range of different parameters provided that the bias time is within a definite time interval. It was observed that twidth, the width of the time window, and topt , the bias time for optimal azimuthal alignment, strongly decrease with the absolute value of the bias voltage. For high bias voltages an extremely low value of topt (20 s at −300 V) was found. Applying the bias conditions longer than topt resulted in a strong decrease of the pole density maxima of the heteroepitaxial grains accompanied by a significant broadening of their azimuthal distribution that is interpreted in terms of two different routes for the loss of epitaxy. The different time constants characterizing the process window for a fixed bias voltage are traced back to feedback of the growing film on the plasma and on the electrical field distribution above the substrate. © 1997 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

In order to clarify the mechanisms that limit the alignment for diamond heteroepitaxy on Si(001) the influence of different process parameters during the bias enhanced nucleation step on the misorientation of diamond on Si(001) was evaluated using x-ray diffraction texture measurements. It is shown that the azimuthal width of the {220} pole density maxima in the substrate plane measured in transmission is a quantity that allows a systematic study of the parameter space for oriented nucleation. From the negligible influence of the substrate surface roughness and of the substrate temperature between 675 and 905 °C it is concluded that the migration, rotation, and rearrangement processes of nucleated diamond clusters do not control alignment in the temperature range studied. In contrast, the duration of the biasing procedure, the process pressure, and the absolute value of the bias voltage can strongly vary the azimuthal distribution between a full width at half-maximum of 3.9° and more than 15°. Low bias voltages favor narrow distributions whereas high bias voltages are accompanied by extremely low biasing times (down to 20 s). When the optimum biasing time is exceeded, the orientation is lost via two different routes. Several models for the underlying mechanisms are proposed with those that are most probable pointing to a detrimental influence by ion bombardment. © 1997 American Institute of Physics.

Electronic Resource

1365-2109

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

This study examined whether rapid recovery from stress-induced impairment in predator evasion, observed in previous studies on coho salmon, Oncorhynchus kisutch (Walbaum), was a general characteristic of different stocks of the same species and different species of Pacific salmon. We monitored stress-induced non-predator mortality, predator evasion and Cortisol concentrations of smolts of coho and spring Chinook, O. tshawytscha (Walbaum), after administration of standardized single and multiple handling stresses. Marked differences in the response to handling stress among stocks of coho and spring chinook smolts were evident, with recovery from impaired predator evasion occurring within 24 h of a 30-s handling stress for coho smolts and 24 h of a 1-min handling stress for spring chinook smolts. Differences in stress-induced non-predator mortality among stocks were also observed. The results point to the importance of screening hatchery salmonid stocks to assess differing capabilities of dealing with stress.

Electronic Resource

1365-2222

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background Previous studies have suggested varying molecular weights for mast cell derived tumour necrosis factor alpha (TNFa) and little data exist upon the factors which may regulate the control of this cytokine in these cells.Objective To determine the molecular weight of canine mastocytoma-derived TNFrt. to determine whether it is pre-formed within the granule and whether its expression could be up-regulated by stem cell factor (SCF).Methods Molecular sizing was assessed by immunoblot. The cellular localization of the TNFα was determined by immunocytochemistry before and after stimulation by A23187 and passive sensitization. Subcellular localization was performed by immuno-gold immunocytochemistry. Changes in the level of mastocytoma mRNA for TNFα in response to stimulation with SCF or fibroblast conditioned media for up to 12 weeks were studied using Northern analysis and changes in the level of TNFα protein expression on immunoblot and immunocytochemistry.Results Mast cells contained authentic 17 kDa TNFα as identified by immunoblotting. Immunocytochemical studies demonstrated preformed TNFα which was released by stimulation with antigen after passive sensitization. or by the calcium ionophore A23187. Further confirmation of the preformed nature of this TNFa was provided by immunogold electron microscopy which localized this cytokine to the granule of the inactive mast cell. Northern blotting revealed a constitutive message for TNFα. which increased in response to fibroblast conditioned media (FCM) and to recombinant human SCF. Immunocytochemical studies of mast cells cultured long-term with FCM or with recombinant SCF showed increased expression of TNFa over the course of 12 weeks incubation with these stimuli.Conclusion Mastocytoma derived—TNFα is a preformed, granule—associated 17 kDa cytokine which is released on stimulation with A23187 or passive sensitization. It is up-regulated by stem cell factor and by FCM over the course of 12 weeks.

Electronic Resource

1365-2109

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Levels of oestrogens in plasma of mature fall-spawning rainbow trout Salmo gairdneri were determined using a radio-immunoassay. No significant difference was found in oestrogen concentration between the sexes (male x̄=2.5 ng/ml; female x̄=4.4 ng/ml); between individual variability was great. Four blood samplings over a 24-h period via cardiac puncture of males revealed no diel variation or change in estrogen levels due to the stress of bleedings. Although no gonado-somatic index-estrogen relationship could be demonstrated for either sex, there was correlation between oestrogen and androgen levels in the female.

Electronic Resource