508 research outputs found
A medico-legal problem
Pain can be either acute or
chronic. Acute pain, while deeply
unpleasant, is vital to our survival;
when it is no longer necessary,
acute pain goes away. Chronic
pain, on the other hand, serves
no useful function, except to
demoralise the sufferer, put a
strain on the family and burden the
nation’s health resources.peer-reviewe
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Investigation of peatland restoration (grip blocking) techniques to achieve best outcomes for methane and greenhouse gas emissions/balance. Controlled Environment (Mesocosm) Experiment. Final Report to Defra. Project code SP1202
Traditional use of shore platforms:a study of the artisanal management of salinas on the Maltese Islands (Central Mediterranean)
Shore platforms and salinas in the Mediterranean region have a long-standing relationship, rooted in the traditional practice
of salt making. On small islands with limited natural resources, the production of salt from seawater, through insolation and
intense human endeavour, offered numerous economic benefits. Salt has been a foremost natural resource for millennia
with a range of uses from preserving edible foods to cooking, cleaning, laundry, and hygiene, and for medicinal uses in dilute
solutions. Within the Maltese Islands, this traditional activity was developed primarily on the soft limestone shore platforms
situated along low-lying rocky coasts. Although coastal production has declined in number over the years, a few salinas have
persisted in their artisanal practice and are becoming a cultural geo-heritage attraction. The aim of this article is to explore
the multiple geographies of this industry on two shore platforms by examining the complicated relationships that have
emerged and molded between the physical landscape and human culture. Mapping out these relations through the traditional
but complex management systems at two salinas, that is, the salinas at Delimara Point (Malta) and those at Xwejni Bay
(Gozo), highlights the delicate nature of these relations as well as the need to support them in order to continually reproduce
the cultural micro-landscape. The resultant micro-landscape is becoming an increasingly important living expression of the
cultural geo-heritage of the Maltese Islands, which requires careful understanding and management of these relations if it is
to be maintained as a vibrant geo-tourist attraction.peer-reviewe
Towards goal-oriented mesh adaptation for fluid-structure interaction
In order to address fluid-structure interaction, we present an a priori analysis
for an ALE compressible flow model. This analysis is the key for an anisotropic metricbased
mesh adaptation
Finding consensus without computation
A canonical problem for swarms of agents is to collectively choose one of multiple options in their environment. We present a novel control strategy for solving this problem-the first to be free of arithmetic computation. The agents do not communicate with each other nor do they store run-time information. They have a line-of-sight sensor that extracts one ternary digit of information from the environment. At every time step, they directly map this information onto constant-value motor commands. We evaluate the control strategy with both simulated and physical e-puck robots. By default, the robots are expected to choose, and move to, one of two options of equal value. The simulation studies show that the strategy is robust against sensory noise, scalable to large swarm sizes, and generalizes to the problems of choosing between more than two options or between unequal options. The experiments-50 trials conducted with a group of 20 e-puck robots-show that the group achieves consensus in 96% of the trials. Given the extremely low hardware requirements of the strategy, it opens up new possibilities for the design of swarms of robots that are small in size (≪10 -3 m) and large in numbers (≫10 3 )
Cross reactivity of an alloantigen present on normal cells with the tumour-specific transplantation-type antigen of the acute myeloid leukaemia (SAL) of rats.
Resistance can be induced in the syngeneic host (August rats) to a myelogeneous leukaemia of spontaneous origin, called SAL, by immunization with allogeneic cells derived form both normal and malignant tissues obtained from the Hooded rat strain. Serological experiments support the conclusion that the antigen involved-referred to as "Ho-SAL"-has the properties of a tumour specific transplantation-type antigen for SAL cells but is a widely expressed alloantigen found in both normal and malignant cells derived from Hooded rats. Antisera to it can be raised in Wistar rats
Occlusion-based cooperative transport with a swarm of miniature mobile robots
This paper proposes a strategy for transporting a large object to a goal using a large number of mobile robots that are significantly smaller than the object. The robots only push the object at positions where the direct line of sight to the goal is occluded by the object. This strategy is fully decentralized and requires neither explicit communication nor specific manipulation mechanisms. We prove that it can transport any convex object in a planar environment. We implement this strategy on the e-puck robotic platform and present systematic experiments with a group of 20 e-pucks transporting three objects of different shapes. The objects were successfully transported to the goal in 43 out of 45 trials. When using a mobile goal, teleoperated by a human, the object could be navigated through an environment with obstacles. We also tested the strategy in a 3-D environment using physics-based computer simulation. Due to its simplicity, the transport strategy is particularly suited for implementation on microscale robotic systems
Oil spill risk assessment on the Maltese coastal areas
A significant percentage of the global oil transport goes through the Mediterranean sea. Most of the maritime traffic carrying oil
and other dangerous liquid substances travels across the Malta Channel. The risk of marine spillages within the stretch of sea
between Malta and Sicily is very high and beaching on the Maltese shores can cause irreversible environmental damage at the
detriment of important economic resources. The aim of this work is to determine the probability and volume percentage of oil that
would reach the coast in case of an accident in the proximity of the Maltese Islands. Various spill scenarios are considered to get a
realistic estimate as much as possible.peer-reviewe
Nullity of a graph with a cut-edge
The nullity of a graph is known to be an analytical tool to predict reactivity and conductivity of molecular π-systems. In this paper we consider the change in nullity when graphs with a cut-edge, and others derived from them, undergo geometrical operations. In particular, we consider the deletion of edges and vertices, the contraction of edges and the insertion of an edge at a coalescence vertex. We also derive three inequalities on the nullity of graphs along the same lines as the consequences of the Interlacing Theorem. These results shed light, in the tight-binding source and sink potential model, on the behaviour of molecular graphs which allow or bar conductivity in the cases when the connections are either distinct or ipso.peer-reviewe
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