416 research outputs found
Not Even Cold in Her Grave: How Postbereavement Remarried Couples Perceive Family Acceptance
Following the interviews of 24 participants concerning the death of their spouse and subsequent remarriage, a pattern of unsolicited responses concerning perceived acceptance of family emerged. Through grounded theory qualitative analysis, a continuum of acceptance was developed ranging from welcoming acceptance to active disapproval. Themes that influenced the perceived level of acceptance were (a) the length of time between death and courtship; (b) the length of the courtship itself; and (c) the level of family involvement in the courtship. Findings support and enhance current literature on remarital adjustment, suggesting it is critical to not only include children, but also the extended family in which the family resides. Provisional hypotheses and clinical implications are provided to help clinicians navigate these complex family dynamics and potentially increase family support
Dark Monopoles in Grand Unified Theories
We consider a Yang-Mills-Higgs theory with gauge group broken to
by a Higgs field in the adjoint
representation. We obtain monopole solutions whose magnetic field is not in the
Cartan Subalgebra. Since their magnetic field vanishes in the direction of the
generator of the electromagnetic group , we call them Dark
Monopoles. These Dark Monopoles must exist in some Grand Unified Theories
(GUTs) without the need to introduce a dark sector. We analyze the particular
case of GUT, where we obtain that their mass is , where is a
monotonically increasing function of with
and We also give a
geometrical interpretation to their non-abelian magnetic charge.Comment: 22 pages; added some comments on possible cosmological implications
of Dark Monopoles in the last section and added some references. Published
Versio
Starting Over: A Tentative Theory Exploring the Effects of Past Relationships on Postbereavement Remarried Couples
Using grounded theory methodology 24 participants were asked to discuss how the death of a previous spouse, either theirs or their partner’s, was currently affecting their second marriage. Participants were interviewed individually and as a couple. The central category was memories of the deceased spouse. Six additional categories emerged from the data: past spouse on pedestal, current/past comparison, insecurity of current spouse, curiosity about past spouse/relationship, partner’s response to curiosity, and impact on the current relationship. Existing literature, auditors, and participant feedback were all used to validate the results. Expanding on a tentative theory (Brimhall, Wampler, & Kimball, 2008), provisional hypotheses were developed, thus helping clinicians who work with complex issues involving remarried couples
Ab initio study of charge transport through single oxygen molecules in atomic aluminum contacts
We present ab initio calculations of transport properties of atomic-sized
aluminum contacts in the presence of oxygen. The experimental situation is
modeled by considering a single oxygen atom (O) or one of the molecules O2 and
O3 bridging the gap between electrodes forming ideal, atomically sharp
pyramids. The transport characteristics are computed for these geometries with
increasing distances between the leads, simulating the opening of a break
junction. To facilitate comparison with experiments further, the vibrational
modes of the oxygen connected to the electrodes are studied. It is found that
in the contact regime the change of transport properties due to the presence of
oxygen is strong and should be detectable in experiments. All three types of
oxygen exhibit a comparable behavior in their vibrational frequencies and
conductances, which are well below the conductance of pure aluminum atomic
contacts. The conductance decreases for an increasing number of oxygen atoms.
In the tunneling regime the conductance decays exponentially with distance and
the decay length depends on whether or not oxygen is present in the junction.
This fact may provide a way to identify the presence of a gas molecule in
metallic atomic contacts.Comment: 8 pages, 9 figures; added appendi
Entwicklung eines Hepatozytenbioreaktors zur Anwendung in der Toxikologie und Metabolismusforschung
New approaches for in vitro testing of hepato-mediated toxicity are undertaken to offer alternatives to in vivo animal testing. The described bioassay for hepato-mediated toxicity testing is based on a small scale hepatocyte-bioreactor with pig hepatocytes connected to a silicon sensor based microphysiometer system for monitoring of the extracellular acidification rate (EAR) of cells and the microphysiometer alone. EAR represents the metabolic activity of tested cells (hepatocytes and ZR 751 cells) under the influence of perfused media, compared to controls, which were set to 100%. Cyclophosphamide (CYCL), whose cytostatic effect is dependent on CYP 450 biotransformation was used as a model substrate. CYCL showed decrease of EAR in hepatocytes, but not in ZR 751 cells. Bioreactor supernatant including CYCL was pumped into the microphysiometer and EARs of the target ZR 751 cell line were recorded. After 7 h of bioreactor supernatant perfusion the ZR 751 cell line showed an EAR decrease of 18.68% +/- 10.18, as compared to controls (bioreactor supernatant from the identical set-up without CYCL). Thus the presented model of hepato-activated toxicity showed an EAR decrease in the ZR 751 cell line that reflected the toxic activation of CYCL by the bioreactor. This new bioassay serves as an example of future applications for hepatocyte bioreactors in automated toxicity testing devices, e.g. in preclinical drug studies or evaluation of hepato-mediated toxicity, not depending on cell destruction or further assays
A thermodynamic perspective on the medium dependence of propagation coefficients and reactivity ratios in radical polymerization
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Lithium catalysed sequence selective ring opening terpolymerisation: a mechanistic study
The catalytic construction of well-defined materials from mixtures of building blocks is an important challenge in sustainable catalysis. In this regard, we have recently reported a new type of selective ring-opening terpolymerisation (ROTERP), in which three monomers (A, B, C) are selectively enchained into a (ABA′C)n sequence, but the reasons behind this unusual selectivity remained unanswered. In this study, we present a detailed investigation into the full ROTERP mechanism based on the reactivity of model intermediates, computational studies investigating >100 possible intermediates and transition states and reaction kinetics. Experimental verification of the intermediate speciation, the primary insertion steps and the side-reactions lets us show that although most insertions and side-reactions are thermodynamically viable, kinetic selection processes at the propagating chain end determine the sequence selectivity. Computational studies elucidate the special role and speciation of the lithium catalyst which during the catalytic cycle involves mono-metallic, bi-metallic and charge separated transition states comprising both coordinative activation of incoming monomers and functional groups of the polymer backbone adjacent to the propagating chain. Our study not only deciphers the mechanism of a rare selective terpolymerisation but also helps answering open questions relevant to ring-opening copolymerisation (ROCOP) and alkali-metal catalysis in general, thus guiding the design of future polymerisation catalysis for degradable materials
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