Tourism and islandscapes: Cultural realignment, social-ecological resilience and change

If, as according to Robin (2015: online), "islands are idealised ecological worlds, the Edens of a fallen planet'", the rationale underpinning tourism expansion should acknowledge MacLeod's (2013) notion of "cultural realignment" that calls for optimal and resilient encounters. This introductory article to the subsequent theme section of the journal on sustainable tourism acts as a bridge toward the development of emergent themes that describe how island peoples adapt and respond in localised cultural islandscapes as a consequence of tourism expansion. The links between cultural alignment and social-ecological resilience are clear and the principal and overarching question posed in this introductory article is: To what extent are islandscapes resilient to rapidly changing utilities, significances and ways of life wrought by tourism expansion? The vulnerabilityresilience duality remains firmly entrenched in the discourse on islands where tourism has become prominent, and although tourism provides some resiliency, overall, islandscapes remain subject to externally driven fast and slow change that exercises an overwhelming influence. Islander agency will likely remain subject to the fluctuations in the demands of the tourism supply chain. Therefore, tourism as a standalone focus of islands is a high-risk proposition, especially in contexts where externally driven change is likely to intensify

Dynamic changes in accumbens dopamine correlate with learning during intracranial self-stimulation

Dopamine in the nucleus accumbens (NAc) is an important neurotransmitter for reward-seeking behaviors such as intracranial self-stimulation (ICSS), although its precise role remains unclear. Here, dynamic fluctuations in extracellular dopamine were measured during ICSS in the rat NAc shell with fast-scan cyclic voltammetry at carbon-fiber microelectrodes. Rats were trained to press a lever to deliver electrical stimulation to the substantia nigra (SNc)/ventral tegmental area (VTA) after the random onset of a cue that predicted reward availability. Latency to respond after cue onset significantly declined across trials, indicative of learning. Dopamine release was evoked by the stimulation but also developed across trials in a time-locked fashion to the cue. Once established, the cue-evoked dopamine transients continued to grow in amplitude, although they were variable from trial to trial. The emergence of cue-evoked dopamine correlated with a decline in electrically evoked dopamine release. Extinction of ICSS resulted in a significant decline in goal-directed behavior coupled to a significant decrease in cue-evoked phasic dopamine across trials. Subsequent reinstatement of ICSS was correlated with a return to preextinction transient amplitudes in response to the cue and reestablishment of ICSS behavior. The results show the dynamic nature of chemical signaling in the NAc during ICSS and provide new insight into the role of NAc dopamine in reward-related behaviors

Cognitive impairment induced by delta9-tetrahydrocannabinol occurs through heteromers between cannabinoid CB1 and serotonin 5-HT2A receptors

Delta-9-tetrahydrocannabinol (THC), the main psychoactive compound of marijuana, induces numerous undesirable effects, including memory impairments, anxiety, and dependence. Conversely, THC also has potentially therapeutic effects, including analgesia, muscle relaxation, and neuroprotection. However, the mechanisms that dissociate these responses are still not known. Using mice lacking the serotonin receptor 5-HT2A, we revealed that the analgesic and amnesic effects of THC are independent of each other: while amnesia induced by THC disappears in the mutant mice, THC can still promote analgesia in these animals. In subsequent molecular studies, we showed that in specific brain regions involved in memory formation, the receptors for THC and the 5-HT2A receptors work together by physically interacting with each other. Experimentally interfering with this interaction prevented the memory deficits induced by THC, but not its analgesic properties. Our results highlight a novel mechanism by which the beneficial analgesic properties of THC can be dissociated from its cognitive side effects

Phasic Dopamine Release Evoked by Abused Substances Requires Cannabinoid Receptor Activation

Transient surges of dopamine in the nucleus accumbens are associated with drug seeking. Using a voltammetric sensor with high temporal and spatial resolution, we demonstrate differences in the temporal profile of dopamine concentration transients caused by acute doses of nicotine, ethanol, and cocaine in the nucleus accumbens shell of freely moving rats. Despite differential release dynamics, all drug effects are uniformly inhibited by administration of rimonabant, a cannabinoid receptor (C

Effectiveness of Metyrapone in Treating Cushing's Syndrome: A Retrospective Multicenter Study in 195 Patients

Background: Cushing's syndrome (CS) is a severe condition with excess mortality and significant morbidity necessitating control of hypercortisolemia. There are few data documenting use of the steroidogenesis inhibitor metyrapone for this purpose. Objective: The objective was to assess the effectiveness of metyrapone in controlling cortisol excess in a contemporary series of patients with CS. Design: This was designed as a retrospective, multicenter study. Setting: Thirteen University hospitals were studied. Patients: We studied a total of 195 patients with proven CS: 115 Cushing's disease, 37 ectopic ACTH syndrome, 43 ACTH-independent disease (adrenocortical carcinoma 10, adrenal adenoma 30, and ACTH-independent adrenal hyperplasia 3). Measurements: Measurements included biochemical parameters of activity of CS: mean serum cortisol “day-curve” (CDC) (target 150–300 nmol/L); 9 am serum cortisol; 24-hour urinary free cortisol (UFC). Results: A total of 164/195 received metyrapone monotherapy. Mean age was 49.6 ± 15.7 years; mean duration of therapy 8 months (median 3 mo, range 3 d to 11.6 y). There were significant improvements on metyrapone, first evaluation to last review: CDC (91 patients, 722.9 nmol/L [26.2 μg/dL] vs 348.6 nmol/L [12.6 μg/dL]; P < .0001); 9 am cortisol (123 patients, 882.9 nmol/L [32.0 μg/dL] vs 491.1 nmol/L [17.8 μg/dL]; P < .0001); and UFC (37 patients, 1483 nmol/24 h [537 μg/24 h] vs 452.6 nmol/24 h [164 μg/24 h]; P = .003). Overall, control at last review: 55%, 43%, 46%, and 76% of patients who had CDCs, UFCs, 9 am cortisol less than 331 nmol/L (12.0 μg/dL), and 9 am cortisol less than upper limit of normal/600 nmol/L (21.7 μg/dL). Median final dose: Cushing's disease 1375 mg; ectopic ACTH syndrome 1500 mg; benign adrenal disease 750 mg; and adrenocortical carcinoma 1250 mg. Adverse events occurred in 25% of patients, mostly mild gastrointestinal upset and dizziness, usually within 2 weeks of initiation or dose increase, all reversible. Conclusions: Metyrapone is effective therapy for short- and long-term control of hypercortisolemia in CS

Feeding Induced by Cannabinoids Is Mediated Independently of the Melanocortin System

Cannabinoids, the active components of marijuana, stimulate appetite, and cannabinoid receptor-1 (CB1-R) antagonists suppress appetite and promote weight loss. Little is known about how CB1-R antagonists affect the central neurocircuitry, specifically the melanocortin system that regulates energy balance

A separated vortex ring underlies the flight of the dandelion

Wind-dispersed plants have evolved ingenious ways to lift their seeds1,2. The common dandelion uses a bundle of drag-enhancing bristles (the pappus) that helps to keep their seeds aloft. This passive flight mechanism is highly effective, enabling seed dispersal over formidable distances3,4; however, the physics underpinning pappus-mediated flight remains unresolved. Here we visualized the flow around dandelion seeds, uncovering an extraordinary type of vortex. This vortex is a ring of recirculating fluid, which is detached owing to the flow passing through the pappus. We hypothesized that the circular disk-like geometry and the porosity of the pappus are the key design features that enable the formation of the separated vortex ring. The porosity gradient was surveyed using microfabricated disks, and a disk with a similar porosity was found to be able to recapitulate the flow behaviour of the pappus. The porosity of the dandelion pappus appears to be tuned precisely to stabilize the vortex, while maximizing aerodynamic loading and minimizing material requirements. The discovery of the separated vortex ring provides evidence of the existence of a new class of fluid behaviour around fluid-immersed bodies that may underlie locomotion, weight reduction and particle retention in biological and manmade structures

Nanotools for Neuroscience and Brain Activity Mapping

Neuroscience is at a crossroads. Great effort is being invested into deciphering specific neural interactions and circuits. At the same time, there exist few general theories or principles that explain brain function. We attribute this disparity, in part, to limitations in current methodologies. Traditional neurophysiological approaches record the activities of one neuron or a few neurons at a time. Neurochemical approaches focus on single neurotransmitters. Yet, there is an increasing realization that neural circuits operate at emergent levels, where the interactions between hundreds or thousands of neurons, utilizing multiple chemical transmitters, generate functional states. Brains function at the nanoscale, so tools to study brains must ultimately operate at this scale, as well. Nanoscience and nanotechnology are poised to provide a rich toolkit of novel methods to explore brain function by enabling simultaneous measurement and manipulation of activity of thousands or even millions of neurons. We and others refer to this goal as the Brain Activity Mapping Project. In this Nano Focus, we discuss how recent developments in nanoscale analysis tools and in the design and synthesis of nanomaterials have generated optical, electrical, and chemical methods that can readily be adapted for use in neuroscience. These approaches represent exciting areas of technical development and research. Moreover, unique opportunities exist for nanoscientists, nanotechnologists, and other physical scientists and engineers to contribute to tackling the challenging problems involved in understanding the fundamentals of brain function