Prior's three-valued modal logic Q was developed as a philosophically interesting modal logic. Thus, we should be able to modify Q as a temporal logic. Although a temporal version of Q was suggested by Prior, the subject has not been fully explored in the literature. In this paper, we develop a three-valued temporal logic $Q_t $ and give its axiomatization and semantics. We also argue that $Q_t $ provides a smooth solution to the problem of future contingents.
Objective—To demonstrate Japanese doctors' and nurses' attitudes towards and practices of voluntary euthanasia (VE) and to compare their attitudes and practices in this regard. Design—Postal survey, conducted between October and December 1999, using a self-administered questionnaire.Participants—All doctor members and nurse members of the Japanese Association of Palliative Medicine.Main outcome measure—Doctors' and nurses' attitude towards and practices of VE.Results—We received 366 completed questionnaires from 642 doctors surveyed (response rate, 58%) and 145 from 217 nurses surveyed (68%). A total of 54% (95% (...) confidence interval (CI): 49-59) of the responding doctors and 53% (CI: 45-61) of the responding nurses had been asked by patients to hasten death, of whom 5% (CI: 2-8) of the former and none of the latter had taken active steps to bring about death. Although 88% (CI: 83-92) of the doctors and 85% (CI: 77-93) of the nurses answered that a patient's request to hasten death can sometimes be rational, only 33% (CI: 28-38) and 23% (CI: 16-30) respectively regarded VE as ethically right and 22% (CI: 18-36) and 15% (CI: 8-20) respectively would practise VE if it were legal. Logistic regression model analysis showed that the respondents' profession was not a statistically independent factor predicting his or her response to any question regarding attitudes towards VE. Conclusions—A minority of responding doctors and nurses thought VE was ethically or legally acceptable. There seems no significant difference in attitudes towards VE between the doctors and nurses. However, only doctors had practised VE. (shrink)
A new thiospinel CuCrZrS4 has been successfully synthesized by a solid-state chemical reaction. This CuCrZrS4 exhibits ferromagnetic properties below the Curie temperature at T c = 60 -2 K. The appearance of irreversible effect between field-cooled and zero-field-cooled magnetization is prominent below around 5 K in a magnetic field of less than 150 Oe. The ac susceptibility ?AC shows a rapid decrease below about 10 K. This low magnetic-field behaviour indicates the existence of a re-entrant spin-glass phase below about 10 (...) K. The dc magnetic susceptibility above 100 K shows Curie-Weiss behaviour with an effective magnetic moment of 3.61 ? B, which is a little less than the spin-only value of 3.87 ? B for the Cr3+ ion. The asymptotic Curie temperature ? P is approximately 65 K, which is a little higher than T c. The valence state is confirmed to be Cu+Cr3+Zr4+S4 2? on the basis of magnetic properties. The electrical resistivity ? shows a semiconducting temperature dependence over the temperature range from 4.2 to 280 K with an activation energy of 6.84 210?3 eV in the higher temperature range from 50 to 283 K. (shrink)
It is difficult to find a typical compound to understand the spin-glass (SG). Only a few model compounds for the SG have been investigated; Fe0.50Mn0.50TiO3 as a short-range interacting three-dimensional (3D) Ising SG, Dy0.103Y0.897Ru2Si2 as a long-range 3D Ising SG, and AgMn as a long-range 3D Heisenberg SG. A spinel-type compound CuCrTiS4 will be provided in this study as a realistic candidate for a short-range interacting 3D Heisenberg SG. This CuCrTiS4 can cause a SG phase below T g?=?7.91?K, which is (...) obtained by a random non-magnetic 50% substitution of Ti for Cr on B-sites in the ferromagnetic mother spinel CuCr2S4. The localized magnetic moment of CuCrTiS4 comes from Cr3+ with S?=?3/2, where a valence state of Cu+Cr3+Ti4+S4 2? is built up. Experimental data will be focused only on the static properties of dc magnetization M(T) under various magnetic fields, without any dynamical magnetic feature. The spin-glass phase transition T g is well defined at low field, nevertheless hardly in higher fields than approximately 40 Oe. An appearance of the field dependence of M(T) of CuCrTiS4 is similar to that of Fe0.50Mn0.50TiO3 with the short-range Ising SG, and also these of AgMn and CuMn with the long-range interacting Heisenberg SGs. This general nature in M(T) seems to originate from the common mechanism under magnetic fields for all the spin-glasses. (shrink)
Although euthanasia has been a pressing ethical and public issue, empirical data are lacking in Japan. We aimed to explore Japanese nurses’ attitudes to patients’ requests for euthanasia and to estimate the proportion of nurses who have taken active steps to hasten death. A postal survey was conducted between October and December 1999 among all nurse members of the Japanese Association of Palliative Medicine, using a self-administered questionnaire based on the one used in a previous survey with Australian nurses in (...) 1991. The response rate was 68%. A total of 53% of the respondents had been asked by patients to hasten their death, but none had taken active steps to bring about death. Only 23% regarded voluntary active euthanasia as something ethically right and 14% would practice it if it were legal. A comparison with empirical data from the previous Australian study suggests a significantly more conservative attitude among Japanese nurses. (shrink)
Quantum mechanics introduces the concept of probability at the fundamental level, yielding the measurement problem. On the other hand, recent progress in cosmology has led to the “multiverse” picture, in which our observed universe is only one of the many, bringing an apparent arbitrariness in defining probabilities, called the measure problem. In this paper, we discuss how these two problems are related with each other, developing a picture for quantum measurement and cosmological histories in the quantum mechanical universe. In order (...) to describe the cosmological dynamics correctly within the full quantum mechanical context, we need to identify the structure of the Hilbert space for a system with gravity. We argue that in order to keep spacetime locality, the Hilbert space for dynamical spacetime must be defined only in restricted spacetime regions: in and on the (stretched) apparent horizon as viewed from a fixed reference frame. This requirement arises from eliminating all the redundancies and overcountings in a general relativistic, global spacetime description of nature. It is responsible for horizon complementarity as well as the “observer dependence” of horizons/spacetime—these phenomena arise to represent changes of the reference frame in the relevant Hilbert space. This can be viewed as an extension of the Poincaré transformation in the quantum gravitational context. Given an initial condition, the evolution of the multiverse state obeys the laws of quantum mechanics—it evolves deterministically and unitarily. The beginning of the multiverse, however, is still an open issue. (shrink)
Ferrimagnetic order in the mixed rare-earth iron garnet (Y1??? x Gd x )3Fe5O12 system has been reinvestigated to cover the temperature range 5.0 to 700?K. The magnetization versus temperature exhibits a systematic variation with changing concentration x. The ferric-ion exchange coupling is strong enough to determine the Curie temperature ≈559?K for all the values x. The compensation temperature at which the magnetization crosses zero (shows the minimum) demonstrates the applicability of the three-sublattice model. The magnetic moment at 5.0?K indicates reasonable (...) agreement with the relation n B?=?|21x???5.0|?B for the (Y1??? x Gd x )3Fe5O12 system. The compensation temperature decreases with decreasing x from 1.0 and reaches zero near x?=?0.24. An enlargement of coercive force in the hysteresis loop for the low-field M-H curve is clearly seen in near the compensation temperature, indicating that a single domain is formed and the rotation of this single domain occurs without building up a multidomain structure. (shrink)