3,300 research outputs found
Towards a higher plane of air transportation security: from hubris to knowledge
Security—in air transportation is an issue of global importance. Since September 11, 2001 there have been numerous events where terrorists have successfully exploited vulnerabilities and weakness in the security system. The authors, both security practitioners and academics—contribute to the discussion of what security in air transportation means—by proposing that the existing system still remains vulnerable to future exploitation by terrorists and other threat groups. The essay proffers a framing device. The meaning of security is considered in terms of our knowledge of the system. It considers air transportation security from the position that our knowledge and understanding is limited by hubris; and explains how this can be improved so that system vulnerabilities are revealed and mitigated against before they are exploited. The essay concerns itself with the notion that air transportation security has a multitude of meanings, and that the system is in a critical state because it is perpetually reliant upon sophisticated technologies to retrospectively plug gaps in the defences. The essay concludes that complexity and hubris create a malign condition—which is not visible to lawmakers, regulators and system designers. And, to improve our understanding of what effective security means we need to look behind the hubristic curtain and grapple with the complexities and vagaries, which are the ingredients to the creation and incubation of system vulnerability and weakness
The Second International African-Caribbean Cancer Consortium for the study of viral, genetic and environmental cancer risk factors
Sleep Disorders, Obesity, Hypertension, and Cardiovascular Risk
In this paper we describe a concept-wise multi-preference semantics for description logic which has its root in the preferential approach for modeling defeasible reasoning in knowledge representation. We argue that this proposal, beside satisfying some desired properties, such as KLM postulates, and avoiding the drowning problem, also defines a plausible notion of semantics. We motivate the plausibility of the concept-wise multi-preference semantics by developing a logical semantics of self-organising maps, which have been proposed as possible candidates to explain the psychological mechanisms underlying category generalisation, in terms of multi-preference interpretations
Urea Applied to Puccinellia-Based Pastures Increases Pasture and Sheep Production
In the 1950\u27s large areas of native vegetation in the upper south east of South Australia (SA) were replaced with highly productive Hunter River lucerne. This maintained groundwater recharge at near pre-clearing levels. The area of lucerne was reduced dramatically in the late 1970\u27s by a combination of lucerne aphids, wingless grasshoppers and drought. In 1981 severe flooding inundated large areas of the region, causing the saline groundwater to rise to the soil surface. Since that time, dryland salinity has been a feature of the local farming system and salt-tolerant pastures based on puccinellia (Puccinellia ciliata) were widely established. Despite this, few agronomic studies have been conducted on puccinellia to enable management guidelines to be determined. The aim of this experiment was to compare animal and pasture production on volunteer saline pasture and improved saline pasture with and without fertiliser inputs
q-Analogue of
A natural embedding for the
corresponding quantum algebras is constructed through the appropriate
comultiplication on the generators of each of the and
algebras. The above embedding is proved in their -boson realization by means
of the isomorphism between the (mn)(m)(n) algebras.Comment: 11 pages, no figures. In memory of professor R. P. Rousse
Impacts of orography on large-scale atmospheric circulation
Some of the largest and most persistent circulation errors in global numerical weather prediction and climate models are attributable to the inadequate representation of the impacts of orography on the atmospheric flow. Existing parametrization approaches attempting to account for unresolved orographic processes, such as turbulent form drag, low-level flow blocking or mountain waves, have been successful to some extent. They capture the basic impacts of the unresolved orography on atmospheric circulation in a qualitatively correct way and have led to significant progress in both numerical weather prediction and climate modelling. These approaches, however, have apparent limitations and inadequacies due to poor observational evidence, insufficient fundamental knowledge and an ambiguous separation between resolved and unresolved orographic scales and between different orographic processes. Numerical weather prediction and climate modelling has advanced to a stage where these inadequacies have become critical and hamper progress by limiting predictive skill on a wide range of spatial and temporal scales. More physically-based approaches are needed to quantify the relative importance of apparently disparate orographic processes and to account for their combined effects in a rational and accurate way in numerical models. We argue that, thanks to recent advances, significant progress can be made by combining theoretical approaches with observations, inverse modelling techniques and high-resolution and idealized numerical simulations
Water erosion on vegetable growing land in south western Australia
The most serious erosion was found to be occurring in the Donnybrook area due to a combination of erosive winter rainfall, steep slopes and erodible soils. The most serious erosion was found to occur when storm runoff entered the vegetable plots from above, providing a transporting medium for the cultivated soil. A predictive model of erosion showed that soil texture, furrow slope, plot length, rainfall erosivity and canopy cover were significant factors affecting soil loss
Dietary intake of choline and plasma choline concentrations in pregnant women in Jamaica
Choline is an essential nutrient for humans and its availability during pregnancy is important for optimal fetal development. The Food and Nutrition Board of the Institute of Medicine in the United States of America has set the adequate choline intake during pregnancy at 450 mg/day. There is limited data available on normal plasma choline concentrations in pregnancy. Moreover, there are neither documented studies of choline intake among pregnant women in the Jamaican population nor of free plasma choline concentrations during pregnancy. Sixteen women presenting to the antenatal clinic of the University Hospital of the West Indies (UHWI) at 10−15 weeks of gestation were selected for this pilot study. A food frequency questionnaire was administered to estimate frequency of consumption of foods rich in choline. Fasting blood samples were collected by venepuncture and plasma assayed for choline using liquid chromatography electrospray ionization isotopic dilution mass spectrometry. Most of the women reported consumption of diets that delivered less than the recommended choline intake (mean ± SEM, 278.5 ± 28.9 mg). Mean plasma choline concentration was 8.4 ± 0.4 μmol/L. This falls below the normal concentration (10 μmol/L) reported for individuals that are not pregnant and pregnant (14.5 μmol/L). The results of this study may be an indication that the choline included in the diet of pregnant women in Jamaica may not be adequate to meet both the needs of the mother and fetus and that further studies are warranted to determine clinical implications
Evidence for an Interaction between CB<sub>1</sub> Cannabinoid and Melanocortin MCR-4 Receptors in Regulating Food Intake
Melanocortin receptor 4 (MCR4) and CB1 cannabinoid receptorsindependently modulate food intake. Although an interactionbetween the cannabinoid and melanocortin systemshas been found in recovery from hemorrhagic shock, the interactionbetween these systems in modulating food intakehas not yet been examined. The present study had two primarypurposes: 1) to examine whether the cannabinoid andmelanocortin systems act independently or synergistically insuppressing food intake; and 2) to determine the relative positionof the CB1 receptors in the chain of control of foodintake in relation to the melanocortin system. Rats were habituatedto the test environment and injection procedure andthen received intracerebroventicular injections of variouscombinations of the MCR4 receptor antagonist JKC-363, thereceptor agonist Δ9-tetrahydrocannabinol, the MCR4 receptoragonist α-MSH, or the cannabinoid CB1 receptor antagonistSR 141716. Food intake and locomotor activity werethen recorded for 120 min. When administrated alone, SR141716 and α-MSH dose-dependently attenuated baselinefeeding, whereas sub-anorectic doses of SR 141716 and α-MSHsynergistically attenuated baseline feeding when combined.Δ9-Tetrahydrocannabinol-induced feeding was not blockedby α-MSH, whereas SR 141716 dose-dependently attenuatedJKC-363-induced feeding. Locomotor activity was not significantlyaffected by any drug treatment, suggesting that theobserved effects on feeding were not due to a nonspecificreduction in motivated behavior. These findings revealed asynergistic interaction between the cannabinoid and melanocortinsystems in feeding behavior. These results furthersuggested that receptors are located downstream frommelanocortin receptors and receptor signaling is necessaryto prevent the melanocortin system from altering foodintake
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