Reentrant Phase Transitions in Rotating AdS Black Holes

We study the thermodynamics of higher-dimensional singly spinning asymptotically AdS black holes in the canonical (fixed J) ensemble of extended phase space, where the cosmological constant is treated as pressure and the corresponding conjugate quantity is interpreted as thermodynamic volume. Along with the usual small/large black hole phase transition, we find a new phenomenon of reentrant phase transitions for all d>5 dimensions, in which a monotonic variation of the temperature yields two phase transitions from large to small and back to large black holes. This situation is similar to that seen in multicomponent liquids.Comment: 5 pages, 6 figure

Kerr-AdS analogue of triple point and solid/liquid/gas phase transition

We study the thermodynamic behavior of multi-spinning d=6 Kerr-anti de Sitter black holes in the canonical ensemble of fixed angular momenta J1 and J2. We find, dependent on the ratio q=J2/J1, qualitatively different interesting phenomena known from the `every day thermodynamics' of simple substances. For q=0 the system exhibits recently observed reentrant large/small/large black hole phase transitions, but for 0<q<<1 we find an analogue of a `solid/liquid' phase transition. Furthermore, for 0.00905<q<0.0985 the system displays the presence of a large/intermediate/small black hole phase transition with one tricritical and two critical points. This behavior is reminiscent of the solid/liquid/gas phase transition except that the coexistence line of small and intermediate black holes does not continue for an arbitrary value of pressure (similar to the solid/liquid coexistence line) but rather terminates at one of the critical points. Finally, for q>0.0985 we observe the `standard liquid/gas behavior' of the Van der Waals fluid.Comment: 5 pages, 7 figures v2: matches the upgraded published versio

Thermodynamics of rotating black holes and black rings: phase transitions and thermodynamic volume

In this review we summarize, expand, and set in context recent developments on the thermodynamics of black holes in extended phase space, where the cosmological constant is interpreted as thermodynamic pressure and treated as a thermodynamic variable in its own right. We specifically consider the thermodynamics of higher-dimensional rotating asymptotically flat and AdS black holes and black rings in a canonical (fixed angular momentum) ensemble. We plot the associated thermodynamic potential-the Gibbs free energy-and study its behaviour to uncover possible thermodynamic phase transitions in these black hole spacetimes. We show that the multiply-rotating Kerr-AdS black holes exhibit a rich set of interesting thermodynamic phenomena analogous to the "every day thermodynamics" of simple substances, such as reentrant phase transitions of multicomponent liquids, multiple first-order solid/liquid/gas phase transitions, and liquid/gas phase transitions of the Van der Waals type. Furthermore, the reentrant phase transitions also occur for multiply-spinning asymptotically flat Myers-Perry black holes. The thermodynamic volume, a quantity conjugate to the thermodynamic pressure, is studied for AdS black rings and demonstrated to satisfy the reverse isoperimetric inequality; this provides a first example of calculation confirming the validity of isoperimetric inequality conjecture for a black hole with non-spherical horizon topology. The equation of state P=P(V,T) is studied for various black holes both numerically and analytically-in the ultraspinning and slow rotation regimes.Comment: 39 pages, 34 figures, invited review for special issue "Aspects of Black Hole Physics" - Galaxie

Gravity is not a Pairwise Local Classical Channel

It is currently believed that there is no experimental evidence on possibly quantum features of gravity or gravity-motivated modifications of quantum mechanics. Here we show that single-atom interference experi- ments achieving large spatial superpositions can rule out a framework where the Newtonian gravitational inter- action is fundamentally classical in the information-theoretic sense: it cannot convey entanglement. Specifically, in this framework gravity acts pairwise between massive particles as classical channels, which effectively induce approximately Newtonian forces between the masses. The experiments indicate that if gravity does reduce to the pairwise Newtonian interaction between atoms at the low energies, this interaction cannot arise from the exchange of just classical information, and in principle has the capacity to create entanglement. We clarify that, contrary to current belief, the classical-channel description of gravity differs from the model of Diosi and Penrose, which is not constrained by the same data.Comment: 13 pages, 5 figures, 2 tables, Late

A survey of Circular Economy initiatives in Portuguese central public sector organisations: National outlook for implementation

The Circular Economy (CE) is generally understood as an opportunity to transform the current unsustainable linear economic system by redesigning the way organisations provide goods and services rethinking how society consumes and uses those resources. In this context, the public sector is mainly recognised as an actor enabling the implementation of a sustainable CE through governmental interventions and policy initiatives. However, there is a lack of studies considering the public sector at an organisational level. CE in organisations includes a wide range of different practices that are important to examine in order to analyse the CE implementation process. Consequently, this study aims to characterise the current state of implementing circular practices and supporting strategies in central public sector organisations. To fulfil this aim, a questionnaire survey was sent to the organisations pertaining to the Portuguese Central Public Administration, as surveys are valuable tools to systematically collect information on various topics. The results demonstrate a relatively low level of implementation. Circular practices such as purchasing remanufactured or used items, using sharing platforms, increasing the efficiency of buildings, adopting green human resources and collaborative initiatives for circularity, and assessing and communicating about CE activities have presented low levels of adoption. At the same time, waste collection for recycling and dematerialisation practices showed good implementation levels. There is, thus, immense potential for further implementation of circularity in central public sector organisations in Portugal. This research contributes to deepening the understanding of the extent to which circular practices are embedded in public sector organisations and identifying the main implementation strengths and weaknesses. This research has the potential to help practitioners and researchers in the transition towards circularity in identifying circular opportunities in their organisations and in building a vision to further implement circularity in public sector organisations

Circular economy practices and strategies in public sector organizations: An integrative review

The concept of the Circular Economy (CE) is an increasingly attractive approach to tackling current sustainability challenges and facilitating a shift away from the linear “take-make-use-dispose” model of production and consumption. The public sector is a major contributor to the CE transition not only as a policy-maker but also as a significant purchaser, consumer, and user of goods and services. The circularization of the public sector itself, however, has received very little attention in CE research. In order to explore the current state of knowledge on the implementation of CE practices and strategies within Public Sector Organizations (PSOs), this research aims to develop an overview of the existing literature. The literature review was designed combining a systematic search with a complementary purposive sampling. Using organizational sustainability as a theoretical perspective, the main results showed a scattered landscape, indicating that the limited research on CE practices and strategies in PSOs has focused so far on the areas of public procurement, internal operations and processes, and public service delivery. As a result of this literature review, an organizational CE framework of a PSO is proposed providing a holistic view of a PSO as a system with organizational dimensions that are relevant for the examination and analysis of the integration process of CE practices and strategies. This innovative framework aims to help further CE research and practice to move beyond current sustainability efforts, highlighting that public procurement, strategy and management, internal processes and operations, assessment and communication, public service delivery, human resources dimensions, collaboration with other organizations, and various external contexts are important public sector areas where the implementation of CE has the potential to bring sustainability benefits

Advancing the Circular Economy in Public Sector Organisations: Employees’ Perspectives on Practices

Circular economy (CE) is a concept that is gaining attention as an approach to help accelerate the transition towards sustainability. Research has focused on the adoption of CE practices in the business sector while the adoption within public sector organisations has been relatively overlooked. Examining CE adoption in the public sector through the perceptive of employees is crucial because of their expertise in the organisation where they work. The main aim of this study is to identify what public employees perceive as suitable CE practices for their organisations and their critical role in implementation. As the adoption of CE practices is influenced by social and material configurations, this research has taken a case study approach, focused on the Portuguese Central Public Administration. Semi-structured interviews were conducted with public employees working on CE and sustainability issues, and a complementary analysis was undertaken of governmental reports and legislative documents. The results show that public employees view the existence and potential of CE practices mainly in the area of public procurement but also in resource efficiency and optimisation, dematerialisation and in practices related to the R-hierarchy including reduce and reuse. Both technical-oriented practices aimed to achieve traditional resource efficiency, and human-centred practices targeted at reducing consumption and sharing resources have been identified. This research provides insights into how a specific group of stakeholders envisions CE activities for their sector. Identification of practices for central public sector has the potential to assist decision-makers in the process of defining priorities for CE planning, implementation and monitoring. This study focusing on CE practices in central public sector organisations contributes to the calls for an inclusion of human/socially-based practices centred around consumption reduction, sharing and dematerialisation activities to enhance the transformative and innovative potential of CE

Influence of Early Stress on Social Abilities and Serotonergic Functions across Generations in Mice

Exposure to adverse environments during early development is a known risk factor for several psychiatric conditions including antisocial behavior and personality disorders. Here, we induced social anxiety and altered social recognition memory in adult mice using unpredictable maternal separation and maternal stress during early postnatal life. We show that these social defects are not only pronounced in the animals directly subjected to stress, but are also transmitted to their offspring across two generations. The defects are associated with impaired serotonergic signaling, in particular, reduced 5HT1A receptor expression in the dorsal raphe nucleus, and increased serotonin level in a dorsal raphe projection area. These findings underscore the susceptibility of social behaviors and serotonergic pathways to early stress, and the persistence of their perturbation across generations

Hotspots and drivers of compound marine heatwaves and low net primary production extremes

Extreme events can severely impact marine organisms and ecosystems. Of particular concern are multivariate compound events, namely when conditions are simultaneously extreme for multiple ocean ecosystem stressors. In 2013–2015 for example, an extensive marine heatwave (MHW), known as the Blob, co-occurred locally with extremely low net primary productivity (NPPX) and negatively impacted marine life in the northeast Pacific. Yet, little is known about the characteristics and drivers of such multivariate compound MHW–NPPX events. Using five different satellite-derived net primary productivity (NPP) estimates and large-ensemble-simulation output of two widely used and comprehensive Earth system models, the Geophysical Fluid Dynamics Laboratory (GFDL) ESM2M-LE and Community Earth System Model version 2 (CESM2-LE), we assess the present-day distribution of compound MHW–NPPX events and investigate their potential drivers on the global scale. The satellite-based estimates and both models reveal hotspots of frequent compound events in the center of the equatorial Pacific and in the subtropical Indian Ocean, where their occurrence is at least 3 times higher (more than 10 d yr−1) than if MHWs (temperature above the seasonally varying 90th-percentile threshold) and NPPX events (NPP below the seasonally varying 10th-percentile threshold) were to occur independently. However, the models show disparities in the northern high latitudes, where compound events are rare in the satellite-based estimates and GFDL ESM2M-LE (less than 3 d yr−1) but relatively frequent in CESM2-LE. In the Southern Ocean south of 60∘ S, low agreement between the observation-based estimates makes it difficult to determine which of the two models better simulates MHW–NPPX events. The frequency patterns can be explained by the drivers of compound events, which vary among the two models and phytoplankton types. In the low latitudes, MHWs are associated with enhanced nutrient limitation on phytoplankton growth, which results in frequent compound MHW–NPPX events in both models. In the high latitudes, NPPX events in GFDL ESM2M-LE are driven by enhanced light limitation, which rarely co-occurs with MHWs, resulting in rare compound events. In contrast, in CESM2-LE, NPPX events in the high latitudes are driven by reduced nutrient supply that often co-occurs with MHWs, moderates phytoplankton growth, and causes biomass to decrease. Compound MHW–NPPX events are associated with a relative shift towards larger phytoplankton in most regions, except in the eastern equatorial Pacific in both models, as well as in the northern high latitudes and between 35 and 50∘ S in CESM2-LE, where the models suggest a shift towards smaller phytoplankton, with potential repercussions on marine ecosystems. Overall, our analysis reveals that the likelihood of compound MHW–NPPX events is contingent on model representation of the factors limiting phytoplankton production. This identifies an important need for improved process understanding in Earth system models used for predicting and projecting compound MHW–NPPX events and their impacts.</p

Confronting agrarian authoritarianism: dynamics of resistance to PROSAVANA in Mozambique

This paper explores how varying degrees of authoritarianism and populism, although not always coinciding, have been intrinsic to the imposition of agrarian policies in Mozambique. Taking the case of ProSAVANA, a highly controversial agrarian development program, we look at how its undemocratic imposition by the state has given rise to a vigorous resistance movement. By tracing a decade of electoral results in selected districts where ProSAVANA is intended to be implemented, we argue that due to its agrarian authoritarian policies which have had negative implications on rural livelihoods, the ruling party, FRELIMO, has recently been losing popularity to the strongest opposition party RENAMO