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This Element presents the philosophy of special relativity: from the foundations of the theory in Newtonian mechanics, through its birth out of the ashes of 19th Century ether theory, through the various conceptual paradoxes which the theory presents, and finally arriving at some of its connections with Einstein's later theory of general relativity. It illustrates concepts such as inertial frames, force-free motion, and dynamical versus geometrical understandings of physics, the standard hierarchy of classical spacetimes, the concept of a symmetry of a physical theory, Poincaré invariant, Einstein's 1905 derivation of the Lorentz transformations, spacetime structure from Aristotle to Minkowski, general covariance, dynamical and geometrical approaches to spacetime, the conventionality of simultaneity, Frame-dependent effects, and the twin paradox.
As wildlife becomes more isolated in human-dominated and rapidly changing environments, species conservation requires investment in landscape connectivity. Identifying stepping stones (discrete areas of suitable habitat that facilitate the movement of dispersing individuals) can help meet connectivity goals. We report the occurrence of the snow leopard Panthera uncia in Ikh Nart Nature Reserve, Mongolia, over 250 km from the nearest known population, one of the easternmost records for the species. Ikh Nart Nature Reserve lies within a region considered highly resistant to movement but harbours high densities of argali sheep Ovis ammon and Siberian ibexes Capra sibirica, both important prey items for snow leopards. This occurrence reveals a new distribution record for the species, the capacity of the species to move across low-quality environments, the value of investment in community conservation and collaborative park management, and the role of remote protected areas such as Ikh Nart Nature Reserve as stepping stones for facilitating population expansion and broader connectivity to other potentially suitable but unoccupied areas.
Among nursing home outbreaks of coronavirus disease 2019 (COVID-19) with ≥3 breakthrough infections when the predominant severe acute respiratory coronavirus virus 2 (SARS-CoV-2) variant circulating was the SARS-CoV-2 δ (delta) variant, fully vaccinated residents were 28% less likely to be infected than were unvaccinated residents. Once infected, they had approximately half the risk for all-cause hospitalization and all-cause death compared with unvaccinated infected residents.
Quizzes are a ubiquitous part of the dementia social care landscape. This article explores why. Using an ethnographic approach which draws on close analysis of communication, we examine dementia quizzes as a ‘social practice’, and what such a lens can tell us about their popularity in social care settings. Vignettes of real interactions drawn from ten different quizzes recorded in four different group settings attended by 28 people living with dementia and 15 staff members are presented to highlight particular issues. We show that the conditions of post-diagnosis dementia social care are uniquely well suited to an activity such as quizzes which are malleable, requiring little preparation or materials, and impose a communication framework which can help to organise the interactional space. Quizzes also draw on previously forged interactional competences, such as turn-taking and question–answer sequences, a skill that has been shown to persist even as dementia progresses. Finally, we argue that the meaning of quizzes with people with dementia feeds into wider societal values and associations attached to memory, dementia and personhood. The extent to which quizzes are akin to a ‘test’ or a fun and enjoyable social activity rests in how they are enacted. We suggest that practice can be adapted, developed and made more inclusive through input from people living with dementia themselves.
This chapter considers the metaphysics of geometric and non-geometric objects as they appear in physical theories such as general relativity, and the interactions between these considerations and the contemporary doctrines of perspectivalism and fragmentalism in the philosophy of science. Taking (following Quine) a kind’s being associated with a projectable predicate as a necessary condition for its being natural, there is a sense in which geometric objects can be assimilated to natural kinds but non-geometric objects cannot; this affords a rational reconstruction of philosophers’ and physicists’ suspicion of the latter (although this verdict can also be questioned). Even granting this, non-geometric objects can nevertheless represent real quantities in a perspectival sense-this is one way in which the perspectival realism doctrine can be endorsed. Moreover, recognising that non-geometric objects can represent real quantities in a perspectival sense affords support for fragmentalism: the view (at least in part) that frame-dependent effects are physically real. That said, one can argue that perspectivalism is superior to fragmentalism. In one sense, perspectivalism should be congenial to proponents of the ‘dynamical approach’ to spacetime theories-however, the pairing is imperfect. Endorsing perspectivalism/fragmentalism in this sense does not commit one to endorsing related-but arguably more opaque-‘structuralist’ views.
In 1918, Emmy Noether, in her paper Invariante Variationsprobleme, proved two theorems (and their converses) on variational problems that went on to revolutionise theoretical physics. 100 years later, the mathematics of Noether's theorems continues to be generalised, and the physical applications of her results continue to diversify. This centenary volume brings together world-leading historians, philosophers, physicists, and mathematicians in order to clarify the historical context of this work, its foundational and philosophical consequences, and its myriad physical applications. Suitable for advanced undergraduate and graduate students and professional researchers, this is a go-to resource for those wishing to understand Noether's work on variational problems and the profound applications which it finds in contemporary physics.
Withdrawal reactions when coming off antidepressants have long been neglected or minimised. It took almost two decades after the selective serotonin reuptake inhibitors (SSRIs) entered the market for the first systematic review to be published. More reviews have followed, demonstrating that the dominant and long-held view that withdrawal is mostly mild, affects only a small minority and resolves spontaneously within 1–2 weeks, was at odd with the sparse but growing evidence base. What the scientific literature reveals is in close agreement with the thousands of service user testimonies available online in large forums. It suggests that withdrawal reactions are quite common, that they may last from a few weeks to several months or even longer, and that they are often severe. These findings are now increasingly acknowledged by official professional bodies and societies.
Reintroduction practitioners must often make critical decisions about reintroduction protocols despite having little understanding of the reintroduction biology of the focal species. To enhance the available knowledge on the reintroduction biology of the warru, or black-footed rock-wallaby Petrogale lateralis MacDonnell Ranges race, we conducted a trial reintroduction of 16 captive individuals into a fenced predator and competitor exclosure on the An̲angu Pitjantjatjara Yankunytjatjara Lands in South Australia. We conducted seven trapping sessions and used radio-tracking and camera traps to monitor survival, reproduction and recruitment to the population over 36 months. Blood samples were collected pre-release and during two trapping sessions post-release to assess nutritional health. The survival rate of founders was 63%, with all losses occurring within 10 weeks of release. Post-release blood biochemistry indicated that surviving warru adapted to their new environment and food sources. Female warru conceived within 6 months of release; 28 births were recorded during the study period and 52% of births successfully recruited to the population. Our results suggest that captive-bred warru are capable of establishing and persisting in the absence of introduced predators. However, the high mortality rate immediately post-release, with only a modest recruitment rate, suggests that future releases into areas where predators and competitors are present should use a trial approach to determine the viability of reintroduction. We recommend that future releases of warru into unfenced areas include an intensive monitoring period in the first 3 months post-release followed by a comprehensive long-term monitoring schedule to facilitate effective adaptive management.
Chronic communal conflicts often embody prisoner's dilemmas. Both communities prefer peace to war. Yet neither trusts the other, viewing the other's gain as its loss, so potentially shared interests often go unrealized. Achieving positive-sum outcomes from apparently zero-sum struggles requires a particular kind of risk-embracing leadership. To succeed leaders must (a) see power relations as potentially positive-sum, (b) strengthen negotiating adversaries when tempted to weaken them, and (c) demonstrate hope for a positive future and take great personal risks to achieve it. Such leadership is exemplified by Nelson Mandela and F. W. de Klerk in the South African democratic transition. To illuminate the strategic dilemmas Mandela and de Klerk faced, we examine the work of Robert Axelrod, Thomas Schelling, and Josep Colomer, who highlight important dimensions of the problem but underplay the role of risk-embracing leadership. Finally we discuss leadership successes and failures in the Northern Ireland settlement and the Israeli-Palestinian conflict.