Self-administration of edible Δ9-tetrahydrocannabinol and associated behavioral effects in mice

Background With increasing access to legal cannabis across the globe, it is imperative to more closely study its behavioral and physiological effects. Furthermore, with the proliferation of cannabis use, modes of consumption are changing, with edible formulations becoming increasingly popular. Nevertheless, there are relatively few animal models of self-administration of the primary psychoactive component of cannabis, Δ9-tetrahydrocannabinol (THC), and almost all incorporate routes of administration other than those used by humans. The aim of the current study was to develop a model of edible THC self-administration and assess its impact on CB1 receptor-mediated behaviors in female and male mice. Methods Mice were given limited access to a palatable dough which occasionally contained THC in doses ranging from 1 to 10 mg/kg. Following dough consumption, mice were assessed for home cage locomotor activity, body temperature, or analgesia. Locomotor activity was also assessed in conjunction with the CB1 receptor antagonist SR141716A. Results Dough was well-consumed, but consumption decreased at the highest THC concentrations. Edible THC produced dose-dependent decreases in locomotor activity and body temperature in both sexes, and these effects were more pronounced in male mice. Hypolocomotion induced by edible THC was attenuated by SR141716A, indicating mediation by CB1 receptor activation. Conclusions In contrast to other cannabinoid self-administration models, edible THC is relatively low in stress and uses a route of administration analogous to one used by humans. Potential applications include chronic THC self-administration, determining THC reward/reinforcement, and investigating consequences of oral THC use

Improving Learning Performance by Applying Economic Knowledge

Digital information economies require information goods producers to learn how to position themselves within a potentially vast product space. Further, the topography of this space is often nonstationary, due to the interactive dynamics of multiple producers changing their position as they try to learn the distribution of consumer preferences and other features of the problem's economic structure. This presents a producer or its agent with a difficult learning problem: how to locate profitable niches in a very large space. In this paper, we present a model of an information goods duopoly and show that, under complete information, producers would prefer not to compete, instead acting as local monopolists and targeting separate niches in the consumer population. However, when producers have no information about the problem they are solving, it can be quite difficult for them to converge on this solution. We show how a modest amount of economic knowledge about the problem can make it much easier, either by reducing the search space, starting in a useful area of the space, or introducing a gradient. These experiments support the hypothesis that a producer using some knowledge of a problem's (economic) structure can outperform a producer that is performing a naive, knowledge-free form of learning.

An Exploration of Core Values and Values Congruence in Local Public Health

Background: Understanding and aligning staff core values with organizational values has been shown to contribute to positive work attitudes and increased organizational performance in the private sector. Little is known about the role of values in local public health. Purpose: To identify public health staff core values, and to improve the alignment between staff values and organizational values (known as values congruence). Methods: A Tribal Leadership exercise was used as part of a multi-stage strategic planning process at Canada’s largest autonomous local public health agency. Results: Five sessions were held with 146 public health staff; 156 different values were reported. These were narrowed down to four core values: collaboration, integrity, empowerment, and striving for excellence. Staff reported high levels of satisfaction with the process and its outcome. Implications: This exploratory case study suggests the Mountains and Valleys exercise can be valuable for assessing public health staff core values, and enhancing values congruence. Further research is needed to explore the relationship between public health values and performance

Model Selection in an Information Economy : Choosing what to Learn

As online markets for the exchange of goods and services become more common, the study of markets composed at least in part of autonomous agents has taken on increasing importance. In contrast to traditional completeinformation economic scenarios, agents that are operating in an electronic marketplace often do so under considerable uncertainty. In order to reduce their uncertainty, these agents must learn about the world around them. When an agent producer is engaged in a learning task in which data collection is costly, such as learning the preferences of a consumer population, it is faced with a classic decision problem: when to explore and when to exploit. If the agent has a limited number of chances to experiment, it must explicitly consider the cost of learning (in terms of foregone profit) against the value of the information acquired. Information goods add an additional dimension to this problem; due to their flexibility, they can be bundled and priced according to a number of different price schedules. An optimizing producer should consider the profit each price schedule can extract, as well as the difficulty of learning of this schedule. In this paper, we demonstrate the tradeoff between complexity and profitability for a number of common price schedules. We begin with a one-shot decision as to which schedule to learn. Schedules with moderate complexity are preferred in the short and medium term, as they are learned quickly, yet extract a significant fraction of the available profit. We then turn to the repeated version of this one-shot decision and show that moderate complexity schedules, in particular two-part tariff, perform well when the producer must adapt to nonstationarity in the consumer population. When a producer can dynamically change schedules as it learns, it can use an explicit decision-theoretic formulation to greedily select the schedule which appears to yield the greatest profit in the next period. By explicitly considering the both the learnability and the profit extracted by different price schedules, a producer can extract more profit as it learns than if it naively chose models that are accurate once learned.Online learning; information economics; model selection; direct search

Speech and narrative: characterisation techniques in the "Aeneid"

The thesis provides a comprehensive analysis of the characterisation of two of the major figures in the Aeneid, Aeneas and Turnus. Particular attention is paid to their direct speeches, all of which are examined and, where relevant, compared to Homeric models and parallels. To this purpose considerable use is made of the indices in Knauer's Die Aeneis und Homer. A more general comparison is made between the dramatic (direct speech) role of Aeneas and those of Homer's Achilles (Iliad) and Odysseus (Odyssey). An appraisal is made (from the viewpoint of depiction of character) of the relationship between the direct and indirect speeches in the Aeneid. Reasons are given to suggest that it is not mere chance, or for the sake of variety, that certain speeches of Aeneas and Turnus are expressed in oratio obliqua. In addition, the narrative portrayal of Aeneas and Turnus is considered in apposition to that of the speeches. A distinction is drawn between Vergil's direct method of characterisation (direct speeches) and his indirect methods (narrative/oratio obliqua). Inevitably, the analysis involves major consideration of the Roman values which pervade the work. All speeches, thoughts and actions of Aeneas and Turnus are assessed in terms of pietas, impietas, furor, virtus, ratio, clementia, humanitas (etc.). It is shown that individual concepts (such as pietas and impietas) are reflected in Vergil's direct and indirect methods of characterisation. The workings of fate and their relevance to the pietas concept are discussed throughout

Are family medicine residents trained to counsel patients on physical activity? The Canadian experience and a call to action.

Physical inactivity is a leading risk factor for non-communicable diseases (NCDs) and early mortality. Family physicians have an important role in providing physical activity counselling to patients to help prevent and treat NCDs. Lack of training on physical activity counselling is a barrier in undergraduate medical education, yet little is known regarding physical activity teaching in postgraduate family medicine residency. We assessed the provision, content and future direction of physical activity teaching in Canadian postgraduate family medicine residency programs to address this data gap. Fewer than half of Canadian Family Medicine Residency Programme directors reported providing structured physical activity counselling education to residents. Most directors reported no imminent plans to change the content or amount of teaching. These results reflect significant gaps between the recommendations of WHO, which calls on doctors to prescribe physical activity, and the current curricular content and needs of family medicine residents. Almost all directors agreed that online educational resources developed to assist residents in physical activity prescription would be beneficial. By describing the provision, content and future direction of physical activity training in family medicine, physicians and medical educators can develop competencies and resources to meet this need. When we equip our future physicians with the necessary tools, we can improve patient outcomes and do our part to reduce the global epidemic of physical inactivity and chronic disease

Dosimetric verification of the anisotropic analytical algorithm for radiotherapy treatment planning

BACKGROUND AND PURPOSE: To investigate the accuracy of photon dose calculations performed by the Anisotropic Analytical Algorithm, in homogeneous and inhomogeneous media and in simulated treatment plans. MATERIALS AND METHODS: Predicted dose distributions were compared with ionisation chamber and film measurements for a series of increasingly complex situations. Initially, simple and complex fields in a homogeneous medium were studied. The effect of inhomogeneities was investigated using a range of phantoms constructed of water, bone and lung substitute materials. Simulated treatment plans were then produced using a semi-anthropomorphic phantom and the delivered doses compared to the doses predicted by the Anisotropic Analytical Algorithm. RESULTS: In a homogeneous medium, agreement was found to be within 2% dose or 2mm dta in most instances. In the presence of heterogeneities, agreement was generally to within 2.5%. The simulated treatment plan measurements agreed to within 2.5% or 2mm. Conclusions: The accuracy of the algorithm was found to be satisfactory at 6MV and 10MV both in homogeneous and inhomogeneous situations and in the simulated treatment plans. The algorithm was more accurate than the Pencil Beam Convolution model, particularly in the presence of low density heterogeneities