Dynamics of rapidly rotating Bose-Einstein condensates in a harmonic plus quartic trap

A two-dimensional rapidly rotating Bose-Einstein condensate in a harmonic plus quartic trap is expected to have unusual vortex states that do not occur in a pure harmonic trap. At a critical rotation speed $\Omega_h$, a central hole appears in the condensate, and at some faster rotation speed $\Omega_g$, the system undergoes a transition to a giant vortex state with pure irrotational flow. Using a time-dependent variational analysis, we study the behavior of an annular condensate with a single concentric ring of vortices. The transition to a giant vortex state is investigated by comparing the energy of the two equilibrium states (the ring of vortices and the giant vortex) and also by studying the dynamical stability of small excitation modes of the ring of vortices.Comment: 12pages, 4figure

Implementing and Breaking Load-Link / Store-Conditional on an ARM-Based System

Manufacturers of modern electronic devices are constantly attempting to implement additional features into ever-increasingly complex and performance demanding systems. This race has been historically driven by improvements in the processor's clock speed, but as power consumption and real estate concerns in the embedded space pose an growing challenge, multithreading approaches have become more prevalent and relied upon. Synchronization is essential to multithreading systems, as it ensures that threads do not interfere with each others' operations and produce reliable and consistent outputs whilst maximizing performance and efficiency. One of the primary mechanisms guaranteeing synchronization in RISC architectures is the load-link/store conditional routine, which implements an atomic operation that allows a thread to obtain a lock. In this study, we implement, test, and manipulate an LL/SC routine in a multithreading environment using GDB. After examining the routine mechanics, we propose a concise implementation in ARMv7l, as well as demonstrate the importance of register integrity and vulnerabilities that occur when integrity is violated under a limited threat model. This work sheds light on LL/SC operations and related lock routines used for multithreading

Metal–Metal Redox Exchange to Produce Heterometallic Manganese–Cobalt Oxo Cubanes via a “Dangler” Intermediate

Pendent metals bound to heterocubanes are components of well-known active sites in enzymes that mediate difficult chemical transformations. Investigations into the specific role of these metal ions, sometimes referred to as "danglers", have been hindered by a paucity of rational synthetic routes to appropriate model structures. To generate pendent metal ions bonded to an oxo cubane through a carboxylate bridge, the cubane Co4(μ3-O)4(OAc)4(t-Bupy)4 (OAc = acetate, t-Bupy = 4-tert-butylpyridine) was exposed to various metal acetate complexes. Reaction with Cu(OAc)2 gave the structurally characterized (by X-ray diffraction) dicopper dangler Cu2Co4(μ4-O)2(μ3-O)2(OAc)6(Cl)2(t-Bupy)4. In contrast, the analogous reaction with Mn(OAc)2 produced the MnIV-containing cubane cation [MnCo3(μ3-O)4(OAc)4(t-Bupy)4]+ by way of a metal-metal exchange that gives Co(OAc)2 and [CoIII(μ-OH)(OAc)]n oligomers as byproducts. Additionally, reaction of the formally CoIV cubane complex [Co4(μ3-O)4(OAc)4(t-Bupy)4][PF6] with Mn(OAc)2 gave the corresponding Mn-containing cubane in 80% yield. A mechanistic examination of the related metal-metal exchange reaction between Co4(μ3-O)4(OBz)4(py)4 (OBz = benzoate) and [Mn(acac)2(py)2][PF6] by ultraviolet-visible (UV-vis) spectroscopy provided support for a process involving rate-determining association of the reactants and electron transfer through a μ-oxo bridge in the adduct intermediate. The rates of exchange correlate with the donor strength of the cubane pyridine and benzoate ligand substituents; more electron-donating pyridine ligands accelerate metal-metal exchange, while both electron-donating and -withdrawing benzoate ligands can accelerate exchange. These experiments suggest that the basicity of the cubane oxo ligands promotes metal-metal exchange reactivity. The redox potentials of the Mn and cubane starting materials and isotopic labeling studies suggest an inner-sphere electron-transfer mechanism in a dangler intermediate

Near-real-time nutrition-sensitive fisheries management

Presentation of PeskAAS system and the novel integration of near-real-time nutrition modelling of catches for use in Timor-Leste fisheries management and food balance shee

Contribution of women\u27s fisheries substantial, but overlooked, in Timor-Leste

2020, The Author(s). A greater understanding of gendered roles in fisheries is necessary to value the often-hidden roles that women play in fisheries and households. We examine women\u27s contributions to household food and income using focus group discussions, market surveys, and landings data in six communities in Timor-Leste. Women were actively fishing more days per month than men. Gleaning was the most frequent activity and 100% of trips returned with catch for food and/or income. Mollusc and crab catches were common and exploitation appeared targeted on a dynamic reappraisal of changing food values and changing estimates of group needs. With as many as 80% of households in coastal areas involved in fishing, and at least 50% of women fishing, this highlights the current lack of women\u27s engagement as a critical gap in fisheries management approaches. The current androcentric dialogue limits social-ecological understanding of these systems and the potential for their effective stewardship

Timor-Leste: strong women, strong nation

Innovative research in the Southeast Asian island nation of Timor-Leste has obtained data to help close the gender gap and provide food security for the local community. In October 2018, Leocaldia de Araujo, a fisherwoman from a village of 300 people at the northern tip of Timor-Leste’s Atauro Island, stepped quietly but confidently on to a stage in the capital, Dili. She was representing women fishers and fishworkers at the National Fisher Forum, the largest fisheries-focused gathering in Timor-Leste since independence. Her presence in front of a predominantly male crowd represented the start of a change taking place in Timor-Leste and its fisheries. She referred to herself and her community as an example of ami povu ki’ik (the poor and marginalized) that need to be heard

The fisheries of Timor-Leste: A 4-year time series analysis covering the COVID-19 pandemic

The time series of data used encompasses the COVID-19 pandemic, and our findings suggest that SSF in Timor-Leste were fairly resilient to the impact. Although they experienced a decline in the market value of the catch, it does not appear to have been as influential as in other countries, where decreases in fishing effort were seen. It is possible that the limited export of aquatic foods from Timor-Leste, and its modest tourism sector, sheltered the fisheries from shocks seen in the fishing sector of other nations. This reflects the persistence of SSF to generate food and income where formal markets and global supply chains are extremely limited. With increasing attention and investment in the country’s fisheries sector to achieve national development goals, it will be critical to consider if modernization and a focus on increasing production will benefit those with the most pressing food and nutritional needs, as well as environmental sustainability. This report provides a benchmark against which to track the progress and development of the fisheries sector in Timor-Leste, and serves as a case study for low-cost digital monitoring of fisheries in data-deficient scenarios

Why human rights matter for marine conservation

Human rights matter for marine conservation because people and nature are inextricably linked. A thriving planet cannot be one that contains widespread human suffering or stifles human potential; and a thriving humanity cannot exist on a dying planet. While the field of marine conservation is increasingly considering human well-being, it retains a legacy in some places of protectionism, colonialism, and fortress conservation. Here, we i) provide an overview of human rights principles and how they relate to marine conservation, ii) document cases where tensions have occurred between marine conservation goals and human rights, iii) review the legal and ethical obligations, and practical benefits, for marine conservation to support human rights, and iv) provide practical guidance on integrating human rights principles into marine conservation. We argue that adopting a human rights-based approach to marine conservation, that is integrating equity as a rights-based condition rather than a charitable principle, will not only help meet legal and ethical obligations to respect, protect, and fulfil human rights, but will also result in greater and more enduring conservation impact

A base-free synthetic route to anti-bimetallic lanthanide pentalene complexes

We report the synthesis and structural characterisation of three homobimetallic complexes featuring divalent lanthanide metals (Ln = Yb, Eu and Sm) bridged by the silylated pentalene ligand [1,4-{SiiPr3}2C8H4]2− (= Pn†). Magnetic measurements and cyclic voltammetry have been used to investigate the extent of intermetallic communication in these systems, in the context of molecular models for organolanthanide based conducting materials