Signature of Quantum Hall Effect Skyrmions in Tunneling: A Theoretical Study

We present a theoretical study of the $I-V$ tunneling characteristic between two parallel two-dimensional electron gases in a perpendicular magnetic field when both are near filling factor $\nu=1$. Finite-size calculations of the single-layer spectral functions in the spherical geometry and analytical expressions for the disk geometry in the thermodynamic limit show that the current in the presence of skyrmions reflects in a direct way their underlying structure. It is also shown that fingerprints of the electron-electron interaction pseudopotentials are present in such a current.Comment: 4 pages, 1 figur

Characterization Of Large-Area Silicon Ionization Detectors For The ACE Mission

We report on extensive tests of large-area (10 cm diameter) high-purity ion-implanted silicon detectors for the solar isotope spectrometer (SIS), and lithium-drifted silicon detectors for the cosmic ray isotope spectrometer (CRIS), which are under development for launch on the advanced composition explorer (ACE) mission. Depletion and breakdown characteristics versus bias were studied, as were long-term current and noise stability in a thermally cycled vacuum. Dead-layer and total thickness maps were obtained using laser interferometry, beams of energetic argon nuclei and radioactive sources of alpha particles. Results, selection criteria, and yields are presented

Dissecting the illegal ivory trade: an analysis of ivory seizures data

Reliable evidence of trends in the illegal ivory trade is important for informing decision making for elephants but it is difficult to obtain due to the covert nature of the trade. The Elephant Trade Information System, a global database of reported seizures of illegal ivory, holds the only extensive information on illicit trade available. However inherent biases in seizure data make it difficult to infer trends; countries differ in their ability to make and report seizures and these differences cannot be directly measured. We developed a new modelling framework to provide quantitative evidence on trends in the illegal ivory trade from seizures data. The framework used Bayesian hierarchical latent variable models to reduce bias in seizures data by identifying proxy variables that describe the variability in seizure and reporting rates between countries and over time. Models produced bias-adjusted smoothed estimates of relative trends in illegal ivory activity for raw and worked ivory in three weight classes. Activity is represented by two indicators describing the number of illegal ivory transactions--Transactions Index--and the total weight of illegal ivory transactions--Weights Index--at global, regional or national levels. Globally, activity was found to be rapidly increasing and at its highest level for 16 years, more than doubling from 2007 to 2011 and tripling from 1998 to 2011. Over 70% of the Transactions Index is from shipments of worked ivory weighing less than 10 kg and the rapid increase since 2007 is mainly due to increased consumption in China. Over 70% of the Weights Index is from shipments of raw ivory weighing at least 100 kg mainly moving from Central and East Africa to Southeast and East Asia. The results tie together recent findings on trends in poaching rates, declining populations and consumption and provide detailed evidence to inform international decision making on elephants

Means versus ends in opaque institutional fields: Trading off compliance and achievement in sustainability standard adoption

__Abstract__ The long-standing discussion on decoupling has recently moved from adopters not implementing the agreed-upon policies to compliant adopters not achieving the goals intended by institutional entrepreneurs. This “means-ends decoupling” prevails especially in highly opaque fields, where practices, causality, and performance are hard to understand and chart. I conceptualize the conditions under which the adoption of institutions in relatively opaque fields leads to the achievement of the envisaged goals. Voluntary sustainability standards governing socioenvironmental issues illustrate these arguments. I argue that the lack of field transparency drives institutional entrepreneurs to create and maintain concrete and uniform rules, apply strong incentives, and disseminate “best practices” to ensure substantive adopter compliance. However, such rigid institutions are ill-equipped to deal with the causal complexity and practice multiplicity underlying opacity while they smother adopter agency. The ensuing tension between substantive compliance and goal achievement leads to an inherent trade-off: institutional entrepreneurs who remedy the policy-practice decoupling may enhance the disparity between means and ends, and vice versa. While sustainability standards and other institutions in highly opaque fields can, therefore, not fully achieve the envisaged goals, the trade-off can be reduced through systemically designed institutions that promote goal internalization and contain niche institutions

History, development and current advances concerning the evolutionary roots of human right‐handedness and language: Brain lateralisation and manual laterality in non‐human primates

International audienceThis review highlights the scientific advances concerning the origins of human right‐handedness and language (speech and gestures). The comparative approach we adopted provides evidence that research on human and non‐human animals’ behavioural asymmetries helps understand the processes that lead to the strong human left‐hemisphere specialisation. We review four major non‐mutually exclusive environmental factors that are likely to have shaped the evolution of human and non‐human primates’ manual asymmetry: socioecological lifestyle, postural characteristics, task‐level complexity and tool use. We hypothesise the following scenario for the evolutionary origins of human right‐handedness: the right‐direction of modern humans’ manual laterality would have emerged from our ecological (terrestrial) and social (multilevel system) lifestyle; then, it would have been strengthened by the gradual adoption of the bipedal stance associated with bipedal locomotion, and the increasing level of complexity of our daily tasks including bimanual coordinated actions and tool use. Although hemispheric functional lateralisation has been shaped through evolution, reports indicate that many factors and their mutual intertwinement can modulate human and non‐human primates’ manual laterality throughout their life cycle: genetic and environmental factors, mainly individual sociodemographic characteristics (e.g., age, sex and rank), behavioural characteristics (e.g., gesture per se and gestural sensory modality) and context‐related characteristics (e.g., emotional context and position of target). These environmental (evolutionary and life cycle) factors could also have influenced primates’ manual asymmetry indirectly through epigenetic modifications. All these findings led us to propose the hypothesis of a multicausal origin of human right‐handedness