Anisotropic low field behavior and the observation of flux jumps in CeCoIn5

The magnetic behavior of the heavy fermion superconductor CeCoIn5 has been investigated. The low field magnetization data show flux jumps in the mixed state of the superconducting phase in a restricted range of temperature. These flux jumps begin to disappear below 1.7 K, and are completely absent at 1.5 K. The magnetization loops are asymmetric, suggesting that surface and geometrical factors dominate the pinning in this system. The lower critical field (Hc1), obtained from the magnetization data, shows a linear temperature dependence and is anisotropic. The calculated penetration depth is also anisotropic, which is consistent with the observation of an anisotropic superconducting gap in CeCoIn5. The critical currents, determined from the high field isothermal magnetization loops, are comparatively low (around 4000 A/cm2 at 1.6 K and 5 kOe).Comment: 4 pages 3 figure

Obesity remodels activity and transcriptional state of a lateral hypothalamic brake on feeding

The current obesity epidemic is a major worldwide health concern. Despite the consensus that the brain regulates energy homeostasis, the neural adaptations governing obesity are unknown. Using a combination of high-throughput single-cell RNA sequencing and longitudinal in vivo two-photon calcium imaging, we surveyed functional alterations of the lateral hypothalamic area (LHA) - a highly conserved brain region that orchestrates feeding - in a mouse model of obesity. The transcriptional profile of LHA glutamatergic neurons was affected by obesity, exhibiting changes indicative of altered neuronal activity. Encoding properties of individual LHA glutamatergic neurons were then tracked throughout obesity, revealing greatly attenuated reward responses.These data demonstrate how diet disrupts the function of an endogenous feeding suppression system to promote overeating and obesity

Planning for artisanal and small-scale mining during EIA: Exploring the potential

This review considers the potential to better plan for artisanal and small-scale mining (ASM) during the Environmental Impact Assessment (EIA) phase of new major mine developments. We contrast and contextualise the parallel development of comprehensive mine closure regulation in South Africa with the resultant lack of progress in actual rehabilitation of its large and growing negative mining legacy. We discuss socio-economic conditions around the mine and the current tendency/flaw in governance that ignores the extensive ASM activities that exist. The ramifications of omitting the known large cumulative impact of ASM compromises efforts to undertake large-scale mine closure effectively both in theory and practice. This leaves some large-scale mine rehabilitation and closure plans unachievable due to cessation attracting ASM activity, consequently ‘re-opening’ the mine. We discuss the EIA process as an existing legal mechanism to generate wider consultation for post-mine ASM activity options, and to formally recognise and incorporate ASM as a known impact to plan for. Governance obligations for mining companies and policymakers should directly cater for ASM, with the focus directed towards mitigating negative consequences and maximising local socio-economic development benefits that the sector can create, managed through EIA processes

Complexities with extractive industries regulation on the African continent: What has ‘best practice’ legislation delivered in South Africa?

The legal framework for mine closure and rehabilitation of new and former mine sites in South Africa, including legacy abandoned sites, is comprehensive. This paper discusses legislative provisions for mine site rehabilitation and closure in South Africa with reference to established international expectations. Overall, while the South African legislative framework for mine closure and rehabilitation generally conforms with international expectations for best practice, the system is extremely complex and unwieldy. Many individual laws, regulations, and guidelines and their corresponding ministries applicable to mine closure planning and management in South Africa has created a complicated inter-connected raft of provisions and expectations. It is an open question whether the most recent amendments (December 2014), have untangled or rather added to the complexities. This historical complexity along with identified governance capacity constraints (financial, technical and experience based) likely explains why implementation of the legislative framework has fallen short of mine closure expectations and mandates. As South Africa is a jurisdiction on the African continent with much experience in mining, there are many lessons that are applicable to emerging countries in the region who wish to attract the benefits of the extractives industries and minimize their potential negative consequences

Larval zebrafish rapidly sense the water flow of a predator's strike

Larval fishes have a remarkable ability to sense and evade the feeding strike of a predator fish with a rapid escape manoeuvre. Although the neuromuscular control of this behaviour is well studied, it is not clear what stimulus allows a larva to sense a predator. Here we show that this escape response is triggered by the water flow created during a predator's strike. Using a novel device, the impulse chamber, zebrafish (Danio rerio) larvae were exposed to this accelerating flow with high repeatability. Larvae responded to this stimulus with an escape response having a latency (mode=13–15 ms) that was fast enough to respond to predators. This flow was detected by the lateral line system, which includes mechanosensory hair cells within the skin. Pharmacologically ablating these cells caused the escape response to diminish, but then recover as the hair cells regenerated. These findings demonstrate that the lateral line system plays a role in predator evasion at this vulnerable stage of growth in fishes

Applied force as a determining factor in lithic use-wear accrual: an experimental investigation of its validity as a method with which to infer hominin upper limb biomechanics

The advent of flake technology represented a fundamental shift in the capability of hominins to effectively access and process animal food sources. As such, the efficiency with which these tools were utilized is often widely implicated in palaeoanthropological debate, most pertinently, with regards to the evolution of upper limb biomechanics. Hence, it would then be of significance if the force, and by association efficiency, with which these tools were used is able to be determined. Presented here is the first attempt to correlate the force with which flaked tools are used to the associated microwear polish accrued on the lithics worked edge. This would potentially allow biomechanical inferences to be taken from stone artifacts and subsequently be applied to the populations that were using them. Twenty five participants of varying strength carried out a simple cutting task using small, unhafted flakes made from English chalk flint. Both maximum and mean applied force was recorded during these tasks by a sensor placed under the worked material while all other variables, including stroke count and flake size, were controlled for. Lithic polish was quantified through seven textural analyses of SEM micrographs. Results indicated that there were no statistically significant relationships between lithic polish and both maximum and mean applied force at low levels of variation. It is, however, suggested that given more archaeologically inferable experimental conditions then polish accrual may have displayed higher developmental distinctions, thus allowing lithic wear to differentiate between applied forces

Cranial capacity in hominid evolution.

Analisi della capacit\ue0 cranica di 118 crani ominidi (appartenenti ai generi Australopithecus e Homo) descritti nella letteratura. Discussione dei possibili modelli evolutivi