289 research outputs found

    Bertrand's Paradox and the Maximum Entropy Principle

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    An important suggestion of objective Bayesians is that the maximum entropy principle can replace a principle which is known to get into paradoxical difficulties: the principle of indifference. No one has previously determined whether the maximum entropy principle is better able to solve Bertrand’s chord paradox than the principle of indifference. In this paper I show that it is not. Additionally, the course of the analysis brings to light a new paradox, a revenge paradox of the chords, that is unique to the maximum entropy principle

    Final Report on the National Geographic Society: Archaeology of Town Planning in Annapolis, Maryland, NGS Grant Number 3116-85

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    The purpose of the research supported by this grant was to refine our understanding of the Baroque town plan of Annapolis, Maryland through archaeology. The plan of 1695, which was prepared under the supervision of Royal Governor Francis Nicholson, has long been considered one of the most sophisticated and best preserved town plans in Colonial North America (Figure1). The town plan is well understood synchronically through the work of a number of scholars, but the plan was less well understood in terms cf its gradual development and alteration over the almost three centuries since it was laid down. Therefore, a primary goal of our work was the initiation of a diachronic understanding of town planning in Annapolis. Further, while the joint Historic Annapolis/ University of Maryland, College Park program called "Archaeology in Annapolis;" had established that a large part of the archaeological record of Annapolis was intact, no one knew how much of the original and subsequent street patterns could be recovered archaeologically, nor exactly how one could go about that. Therefore, the second aspect of this project was to establish a set of methods to document street and lot borders. Such a project was urgent since the city of Annapolis plans to dig trenches throughout the core of the Nicholson Plan to bury utility wires. Among other things, these utility trenches provided an opportunity to understand how the third dimension of a Baroque town plan, depth, was handled. This work will allow us to see how the plan was used through time to structure activities and in turn how it was altered to better suit them

    A Copper-Salicylate Gel for Pain Relief in Osteoarthritis: a Randomised Controlled Trial

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    Objective: To assess the efficacy and safety of a copper-salicylate gel in osteoarthritis of the hip and knee. Design: Randomised, double-blind, placebo-controlled study. Setting: Rheumatology Clinic of St Vincent's Hospital, Sydney, New South Wales (a tertiary referral hospital), June 1993 to October 1994. Patients: 116 patients with pain associated with osteoarthritis of the hip and/or knee (diagnosed by criteria of the European League against Rheumatism), drawn from patients attending the Clinic or self-referred after newspaper advertisements. Intervention: Copper-salicylate or placebo gel (1.5 g) applied twice daily to the forearm for four weeks. Outcome measures: Self-assessment of pain before the trial and after two and four weeks of treatment; patient and investigator assessments of efficacy; additional analgesia required; adverse reactions; and withdrawal rates. Results: Pain scores at rest and on movement decreased in both the copper-salicylate and placebo groups by 13%-20%. There was no significant difference between the two groups for decrease in pain score, patient and investigator efficacy ratings, number of patients requiring paracetamol for extra analgesia (active, 77%; placebo, 71%) and average dose of paracetamol (active, 555 mg/day; placebo, 600 mg/day). Significantly more patients in the copper-salicylate group reported adverse reactions (83% versus 52% of the placebo group), most commonly skin reactions, and withdrew from the trial because of these reactions (17% versus 1.7% of the placebo group). Conclusion: Copper-salicylate gel applied to the forearm was no better than placebo gel as pain relief for patients with osteoarthritis of the hip or knee, but produced significantly more skin rashes

    Midday measurements of leaf water potential and stomatal conductance are highly correlated with daily water use of Thompson Seedless grapevines

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    A study was conducted to determine the relationship between midday measurements of vine water status and daily water use of grapevines measured with a weighing lysimeter. Water applications to the vines were terminated on August 24th for 9 days and again on September 14th for 22 days. Daily water use of the vines in the lysimeter (ETLYS) was approximately 40 L vine−1 (5.3 mm) prior to turning the pump off, and it decreased to 22.3 L vine−1 by September 2nd. Pre-dawn leaf water potential (ΨPD) and midday Ψl on August 24th were −0.075 and −0.76 MPa, respectively, with midday Ψl decreasing to −1.28 MPa on September 2nd. Leaf g s decreased from ~500 to ~200 mmol m−2 s−1 during the two dry-down periods. Midday measurements of g s and Ψl were significantly correlated with one another (r = 0.96) and both with ETLYS/ETo (r = ~0.9). The decreases in Ψl, g s, and ETLYS/ETo in this study were also a linear function of the decrease in volumetric soil water content. The results indicate that even modest water stress can greatly reduce grapevine water use and that short-term measures of vine water status taken at midday are a reflection of daily grapevine water us

    Establishing a Reference Baseline for Midday Stem Water Potential in Olive and Its Use for Plant-Based Irrigation Management

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    Midday stem water potential (SWP) is rapidly becoming adopted as a standard tool for plant-based irrigation management in many woody perennial crops. A reference or “baseline” SWP has been used in some crops (almond, prune, grape, and walnut) to account for the climatic influence of air vapor pressure deficit (VPD) on SWP under non-limiting soil moisture conditions. The baseline can be determined empirically for field trees maintained under such non-limiting conditions, but such conditions are difficult to achieve for an entire season. We present the results of an alternative survey-based approach, using a large set of SWP and VPD data collected over multiple years, from irrigation experiments in olive orchards located in multiple countries [Spain, United States (California), Italy, and Argentina]. The relation of SWP to midday VPD across the entire data set was consistent with an upper limit SWP which declined with VPD, with the upper limit being similar to that found in Prunus. A best fit linear regression estimate for this upper limit (baseline) was found by selecting the maximum R2 and minimum probability for various upper fractions of the SWP/VPD relation. In addition to being surprisingly similar to the Prunus baseline, the olive baseline was also similar (within 0.1 MPa) to a recently published mechanistic olive soil-plant-atmosphere-continuum (SPAC) model for “super high density” orchard systems. Despite similarities in the baseline, the overall physiological range of SWP exhibited by olive extends to about −8 MPa, compared to about −4 MPa for economically producing almond. This may indicate that, despite species differences in physiological responses to low water availability (drought), there may be convergent adaptations/acclimations across species to high levels of water availability. Similar to its use in other crops, the olive baseline will enable more accurate and reproducible plant-based irrigation management for both full and deficit irrigation practices, and we present tentative SWP guidelines for this purpose

    The influence of affordances on user preferences for multimedia language learning applications.

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    This study investigates the influence of sensory and cognitive affordances on the user experience of mobile devices for multimedia language learning applications. A primarily audio-based language learning application – ‘Vowel Trainer’, was chosen against a comparison, text and picture-based language learning application – ‘Learn English for Taxi Drivers’. Impressions of the two applications were assessed on two different devices that have virtually the same interface and identical sound output (when headphones are used), but differ in physical size: the iPhone and the iPad. A mixed design was chosen, with native language as a group factor and device type (iPad vs. iPhone) and language application type (audio vs. video) as within groups factors. Assessments of sensory and cognitive affordances were made, along with measurement of learner preferences of each application. Data from 41 participants (21 native English speakers, 20 non-native English speakers) were analysed, revealing device differences in both audio and visual subjective quality ratings, despite only visual quality being affected by the device's physical limitations. We suggest that sensory affordances (indexed by subjective quality) are not simply a function of physical limitations, but are heavily influenced by context. The implications for developing design guidelines for language learning and other multimedia applications are discussed

    Using Ethnographic Methods to Articulate Community-Based Conceptions of Cultural Heritage Management

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    How can ethnographic methods help communities articulate and enact their own conceptions of heritage management? This and related questions are being explored through an international research project, ‘Intellectual Property Issues in Cultural Heritage’. The project includes up to twenty community- based initiatives that incorporate community-based participatory research and ethnographic methods to explore emerging intellectual property-related issues in archaeological contexts; the means by which they are being addressed or resolved; and the broader implications of these issues and concerns. We discuss three examples that use ethnography to (a) articulate local or customary laws and principles of archaeological heritage management among a First Nations group in British Columbia; (b) assemble knowledge related to land/sea use and cultural practices of the Moriori people of Rekohu (Chatham Islands) for their use in future land and heritage manage- ment policies; and (c) aid a tribal cultural centre in Michigan in crafting co-management strategies to protect spiritual traditions associated with a rock art site on state property. Such situations call for participatory methods that place control over the design, process, products, and interpretation of ‘archaeology’ in the hands of cultural descendants. We hope that these examples of community-based conceptions of archaeological heritage management, facilitated through ethnographic methods and participatory approaches, will increase awareness of the value of these and other alternative approaches and the need to share them widely

    A suberized exodermis is required for tomato drought tolerance.

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    Plant roots integrate environmental signals with development using exquisite spatiotemporal control. This is apparent in the deposition of suberin, an apoplastic diffusion barrier, which regulates flow of water, solutes and gases, and is environmentally plastic. Suberin is considered a hallmark of endodermal differentiation but is absent in the tomato endodermis. Instead, suberin is present in the exodermis, a cell type that is absent in the model organism Arabidopsis thaliana. Here we demonstrate that the suberin regulatory network has the same parts driving suberin production in the tomato exodermis and the Arabidopsis endodermis. Despite this co-option of network components, the network has undergone rewiring to drive distinct spatial expression and with distinct contributions of specific genes. Functional genetic analyses of the tomato MYB92 transcription factor and ASFT enzyme demonstrate the importance of exodermal suberin for a plant water-deficit response and that the exodermal barrier serves an equivalent function to that of the endodermis and can act in its place
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