Consent for research on violence against children: dilemmas and contradictions

The increasing visibility of violence involving children has led to a recognition of the need to research its underlying dynamics. As a result, we now have a better understanding of the complexities involved in this kind of research, associated with children’s developmental characteristics and social status, exposure to violence, and compromised parenting of caregivers. This paper discusses the issues raised by parental consent in research on violence against children, specifically the dilemma of children’s rights to participation and protection, and proposes changes in research practice in this domain.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article. This study had financial support from National Funds through the FCT (Foundation for Science and Technology) through CIEC (Research Centre on Child Studies), with the reference UID/CED/00317/2019

Medical Assistance in Dying (MAiD): Ethical Considerations for Psychologists

Significant ethical challenges arise when mental health practitioners care for patients who seek to accelerate their own dying for rational medically valid reasons. Current and proposed laws provide for medical assistance in dying (MAiD) in several U.S. jurisdictions, all of Canada, and several other nations. Differing provisions of these laws complicate their utility for some patients who seek aid in dying. Some extant laws include roles that mental health professionals might play in assessing patients’ competence or capacity to consent, mental illness, or other cognitive and behavioral factors. Practitioners who choose to accept roles in the MAiD process must consider and resolve a number of ethical challenges including potential conflicts between and among laws, ethical standards, third-party requests, personal values, and patients’ wishes. These include becoming aware of patients who may wish to act independently to end their lives when MAiD laws might otherwise exclude them. Examples from actual cases and the resultant discussion will form a basis for exploration of the ethical and legal complexities confronted when psychologists become engaged in the process either intentionally or incidentally. The lead article (Koocher) is not intended to comprehensively address MAiD in all of its complexity but rather to trigger a thoughtful discussion among the accompanying commentaries

Discovery of highly-polarizable semiconductors BaZrS3 and Ba3Zr2S7

There are few known semiconductors exhibiting both strong optical response and large dielectric polarizability. Inorganic materials with large dielectric polarizability tend to be wide-band gap complex oxides. Semiconductors with strong photoresponse to visible and infrared light tend to be weakly polarizable. Interesting exceptions to these trends are halide perovskites and phase-change chalcogenides. Here we introduce complex chalcogenides in the Ba-Zr-S system in perovskite and Ruddlesden-Popper structures as a new family of highly polarizable semiconductors. We report the results of impedance spectroscopy on single crystals that establish BaZrS3 and Ba3Zr2S7 as semiconductors with low-frequency relative dielectric constant (${\epsilon}_0$) in the range 50 - 100, and band gap in the range 1.3 - 1.8 eV. Our electronic structure calculations indicate the enhanced dielectric response in perovskite BaZrS3 versus Ruddlesden-Popper Ba3Zr2S7 is primarily due to enhanced IR mode-effective charges, and variations in phonon frequencies along $\langle 001 \rangle$; differences in the Born effective charges and the lattice stiffness are of secondary importance. This combination of covalent bonding in crystal structures more common to complex oxides results in a sizable Fr\"ohlich coupling constant, which suggests that charge carriers are large polarons.Comment: 22 pages, 5 figure

Discovery of highly polarizable semiconductors BaZrS₃ and Ba₃Zr₂S₇

There are few known semiconductors exhibiting both strong optical response and large dielectric polarizability. Inorganic materials with large dielectric polarizability tend to be wide-band gap complex oxides. Semiconductors with a strong photoresponse to visible and infrared light tend to be weakly polarizable. Interesting exceptions to these trends are halide perovskites and phase-change chalcogenides. Here we introduce complex chalcogenides in the Ba-Zr-S system in perovskite and Ruddlesden-Popper structures as a family of highly polarizable semiconductors. We report the results of impedance spectroscopy on single crystals that establish BaZrS₃ and Ba₃Zr₂S₇ as semiconductors with a low-frequency relative dielectric constant ɛ0 in the range 50–100 and band gap in the range 1.3–1.8 eV. Our electronic structure calculations indicate that the enhanced dielectric response in perovskite BaZrS₃ versus Ruddlesden-Popper Ba₃Zr₂S₇ is primarily due to enhanced IR mode-effective charges and variations in phonon frequencies along 〈001〉; differences in the Born effective charges and the lattice stiffness are of secondary importance. This combination of covalent bonding in crystal structures more common to complex oxides, but comprising sulfur, results in a sizable Fröhlich coupling constant, which suggests that charge carriers are large polarons

Evidence for the weakly coupled electron mechanism in an Anderson-Blount polar metal

Over 50 years ago, Anderson and Blount proposed that ferroelectric-like structural phase transitions may occur in metals, despite the expected screening of the Coulomb interactions that often drive polar transitions. Recently, theoretical treatments have suggested that such transitions require the itinerant electrons be decoupled from the soft transverse optical phonons responsible for polar order. However, this decoupled electron mechanism (DEM) has yet to be experimentally observed. Here we utilize ultrafast spectroscopy to uncover evidence of the DEM in LiOsO_3, the first known band metal to undergo a thermally driven polar phase transition (T_c ≈ 140 K). We demonstrate that intra-band photo-carriers relax by selectively coupling to only a subset of the phonon spectrum, leaving as much as 60% of the lattice heat capacity decoupled. This decoupled heat capacity is shown to be consistent with a previously undetected and partially displacive TO polar mode, indicating the DEM in LiOsO_3

Computationally Directed Discovery of MoBi\u3csub\u3e2\u3c/sub\u3e

Incorporating bismuth, the heaviest element stable to radioactive decay, into new materials enables the creation of emergent properties such as permanent magnetism, superconductivity, and nontrivial topology. Understanding the factors that drive Bi reactivity is critical for the realization of these properties. Using pressure as a tunable synthetic vector, we can access unexplored regions of phase space to foster reactivity between elements that do not react under ambient conditions. Furthermore, combining computational and experimental methods for materials discovery at high-pressures provides broader insight into the thermodynamic landscape than can be achieved through experiment alone, informing our understanding of the dominant chemical factors governing structure formation. Herein, we report our combined computational and experimental exploration of the Mo–Bi system, for which no binary intermetallic structures were previously known. Using the ab initio random structure searching (AIRSS) approach, we identified multiple synthetic targets between 0–50 GPa. High-pressure in situ powder X-ray diffraction experiments performed in diamond anvil cells confirmed that Mo–Bi mixtures exhibit rich chemistry upon the application of pressure, including experimental realization of the computationally predicted CuAl2-type MoBi2 structure at 35.8(5) GPa. Electronic structure and phonon dispersion calculations on MoBi2 revealed a correlation between valence electron count and bonding in high-pressure transition metal–Bi structures as well as identified two dynamically stable ambient pressure polymorphs. Our study demonstrates the power of the combined computational–experimental approach in capturing high-pressure reactivity for efficient materials discovery

Democracy: the forgotten challenge for bioethics in the developing countries

<p>Abstract</p> <p>Background</p> <p>Bioethics as a field related to the health system and health service delivery has grown in the second half of the 20^thcentury, mainly in North America. This is attributed, the author argues, to mainly three kinds of development that took place in the developed countries at a pace different than the developing countries. They are namely: development of the health system; moral development; and political development.</p> <p>Discussion</p> <p>This article discusses the factors that impede the development of the field of bioethics from an academic activity to a living field that is known and practiced by the people in the developing countries. They are quite many; however, the emphasis here is on role of the political structure in the developing countries and how it negatively affects the development of bioethics. It presents an argument that if bioethics is to grow within the system of health service, it should be accompanied by a parallel changes in the political mindsets in these countries.</p> <p>Summary</p> <p>For bioethics to flourish in developing countries, it needs an atmosphere of freedom where people can practice free moral reasoning and have full potential to take their life decisions by themselves. Moreover, bioethics could be a tool for political change through the empowerment of people, especially the vulnerable.</p> <p>To achieve that, the article is proposing a practical framework for facilitating the development of the field of bioethics in the developing countries.</p