419 research outputs found

    A methodology to understand student choice of Higher Education Institutions: the case of the United Kingdom

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    The need to understand how prospective students decide which Higher Education Institution to attend is becoming of paramount importance as the policy context for Higher Education moves towards market-based systems in many countries. This paper provides a novel methodology by which student preferences between institutions can be assessed, using the UK as a case study. It applies both revealed preference and discrete choice modelling techniques to estimate the priority attributes and potential trade-offs of students choosing between different United Kingdom universities. Whereas the former methodology has the advantage of being based on actual decisions, the latter provides an experimental setting for more nuanced findings to be elicited; the combination of approaches allows for a rich and detailed set of results. This methodology can also be used to ask detailed strategic questions of higher education institutions, and further applied to other international markets

    Approximating Optimal Behavioural Strategies Down to Rules-of-Thumb: Energy Reserve Changes in Pairs of Social Foragers

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    Functional explanations of behaviour often propose optimal strategies for organisms to follow. These ‘best’ strategies could be difficult to perform given biological constraints such as neural architecture and physiological constraints. Instead, simple heuristics or ‘rules-of-thumb’ that approximate these optimal strategies may instead be performed. From a modelling perspective, rules-of-thumb are also useful tools for considering how group behaviour is shaped by the behaviours of individuals. Using simple rules-of-thumb reduces the complexity of these models, but care needs to be taken to use rules that are biologically relevant. Here, we investigate the similarity between the outputs of a two-player dynamic foraging game (which generated optimal but complex solutions) and a computational simulation of the behaviours of the two members of a foraging pair, who instead followed a rule-of-thumb approximation of the game's output. The original game generated complex results, and we demonstrate here that the simulations following the much-simplified rules-of-thumb also generate complex results, suggesting that the rule-of-thumb was sufficient to make some of the model outcomes unpredictable. There was some agreement between both modelling techniques, but some differences arose – particularly when pair members were not identical in how they gained and lost energy. We argue that exploring how rules-of-thumb perform in comparison to their optimal counterparts is an important exercise for biologically validating the output of agent-based models of group behaviour

    Separating the effects of predation risk and interrupted foraging upon mass changes in the blue tit Parus caeruleus

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    The optimal amount of reserves that a small bird should carry depends upon a number of factors, including the availability of food and environmental predation risk levels. Theory predicts that, if predation risk increases, then a bird should maintain a lower level of reserves. Previous experiments have given mixed results: some have shown reduced reserves and some, increased reserves. However, the birds in these studies may have been interpreting a staged predation event as a period when they were unable to feed rather than a change in predation risk: theory predicts that, if the food supply within the environment is variable, then reserves should be increased. In the present study, we presented blue tits (Parus caeruleus) with a potential predator and compared this response (which could have been potentially confounded by perceived interruption e¡ects) with a response to an actual interruption in the environment during both long and short daytime lengths. During long (but not short) days, the birds responded in line with theoretical predictions by increasing their reserves in response to interruption and reducing them in response to predation. These results are examined in the light of other experimental manipulations and we discuss how well experimental tests have tested the predictions made by theoretical models

    Black-headed gulls synchronise their activity with their nearest neighbours

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    A Technique for Measuring Petal Gloss, with Examples from the Namaqualand Flora

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    The degree of floral gloss varies between species. However, little is known about this distinctive floral trait, even though it could be a key feature of floral biotic and abiotic interactions. One reason for the absence of knowledge is the lack of a simple, repeatable method of gloss measurement that can be used in the field to study floral gloss. A protocol is described for measuring gloss in petal samples collected in the field, using a glossmeter. Repeatability of the technique is assessed. We demonstrate a simple yet highly accurate and repeatable method that can easily be implemented in the field. We also highlight the huge variety of glossiness found within flowers and between species in a sample of spring-blooming flowers collected in Namaqualand, South Africa. We discuss the potential uses of this method and its applications for furthering studies in plant-pollinator interactions. We also discuss the potential functions of gloss in flowers

    Statistics of lattice animals (polyominoes) and polygons

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    We have developed an improved algorithm that allows us to enumerate the number of site animals (polyominoes) on the square lattice up to size 46. Analysis of the resulting series yields an improved estimate, τ=4.062570(8)\tau = 4.062570(8), for the growth constant of lattice animals and confirms to a very high degree of certainty that the generating function has a logarithmic divergence. We prove the bound τ>3.90318.\tau > 3.90318. We also calculate the radius of gyration of both lattice animals and polygons enumerated by area. The analysis of the radius of gyration series yields the estimate ν=0.64115(5)\nu = 0.64115(5), for both animals and polygons enumerated by area. The mean perimeter of polygons of area nn is also calculated. A number of new amplitude estimates are given.Comment: 10 pages, 2 eps figure

    Scalable Rules for Coherent Group Motion in a Gregarious Vertebrate

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    Individuals of gregarious species that initiate collective movement require mechanisms of cohesion in order to maintain advantages of group living. One fundamental question in the study of collective movement is what individual rules are employed when making movement decisions. Previous studies have revealed that group movements often depend on social interactions among individual members and specifically that collective decisions to move often follow a quorum-like response. However, these studies either did not quantify the response function at the individual scale (but rather tested hypotheses based on group-level behaviours), or they used a single group size and did not demonstrate which social stimuli influence the individual decision-making process. One challenge in the study of collective movement has been to discriminate between a common response to an external stimulus and the synchronization of behaviours resulting from social interactions. Here we discriminate between these two mechanisms by triggering the departure of one trained Merino sheep (Ovis aries) from groups containing one, three, five and seven naïve individuals. Each individual was thus exposed to various combinations of already-departed and non-departed individuals, depending on its rank of departure. To investigate which individual mechanisms are involved in maintaining group cohesion under conditions of leadership, we quantified the temporal dynamic of response at the individual scale. We found that individuals' decisions to move do not follow a quorum response but rather follow a rule based on a double mimetic effect: attraction to already-departed individuals and attraction to non-departed individuals. This rule is shown to be in agreement with an adaptive strategy that is inherently scalable as a function of group size

    Differences in Nutrient Requirements Imply a Non-Linear Emergence of Leaders in Animal Groups

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    Collective decision making and especially leadership in groups are among the most studied topics in natural, social, and political sciences. Previous studies have shown that some individuals are more likely to be leaders because of their social power or the pertinent information they possess. One challenge for all group members, however, is to satisfy their needs. In many situations, we do not yet know how individuals within groups distribute leadership decisions between themselves in order to satisfy time-varying individual requirements. To gain insight into this problem, we build a dynamic model where group members have to satisfy different needs but are not aware of each other's needs. Data about needs of animals come from real data observed in macaques. Several studies showed that a collective movement may be initiated by a single individual. This individual may be the dominant one, the oldest one, but also the one having the highest physiological needs. In our model, the individual with the lowest reserve initiates movements and decides for all its conspecifics. This simple rule leads to a viable decision-making system where all individuals may lead the group at one moment and thus suit their requirements. However, a single individual becomes the leader in 38% to 95% of cases and the leadership is unequally (according to an exponential law) distributed according to the heterogeneity of needs in the group. The results showed that this non-linearity emerges when one group member reaches physiological requirements, mainly the nutrient ones – protein, energy and water depending on weight - superior to those of its conspecifics. This amplification may explain why some leaders could appear in animal groups without any despotism, complex signalling, or developed cognitive ability

    Floral temperature and optimal foraging: is heat a feasible floral reward for pollinators?

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    As well as nutritional rewards, some plants also reward ectothermic pollinators with warmth. Bumble bees have some control over their temperature, but have been shown to forage at warmer flowers when given a choice, suggesting that there is some advantage to them of foraging at warm flowers (such as reducing the energy required to raise their body to flight temperature before leaving the flower). We describe a model that considers how a heat reward affects the foraging behaviour in a thermogenic central-place forager (such as a bumble bee). We show that although the pollinator should spend a longer time on individual flowers if they are warm, the increase in total visit time is likely to be small. The pollinator's net rate of energy gain will be increased by landing on warmer flowers. Therefore, if a plant provides a heat reward, it could reduce the amount of nectar it produces, whilst still providing its pollinator with the same net rate of gain. We suggest how heat rewards may link with plant life history strategies

    Education for Sustainable Development: Towards the Sustainable University

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    We  planned  this  conference  in  anticipation  of  the  end  of  the  UN  Decade  of  Education  for  Sustainable   Development  (DESD),  and  the  start  of  the  next  phase  for  those  involved  in  ESD  here  and   internationally.    At  Plymouth  University,  2015  marks  ten  year  anniversary  since  cross-­‐institutional   work  on  sustainability  and  sustainability  education  was  spearheaded  by  the  founding  of  the  Centre  for   Sustainable  Futures  (CSF).    Coincidentally,  2015  also  marks  a  ten  years  since  the  influential  HEFCE   policy  document  ‘Sustainable  Development  in  Higher  Education’  was  released.   Holding  the  conference  in  January  –  named  after  the  Roman  god  of  doorways,  of  endings  and   beginnings  –  we  sought  to  look  at  some  of  what  has  been  achieved  in  sustainability  education  to  date   and  explore  its  prospects  as  we  move  forward.   Following  an  enthusiastic  response  to  the  call  for  abstracts,  the  conference  featured  a  diverse  range   of  research  papers,  posters,  and  roundtable  presentations  from  academics  and  practitioners  across   the  UK  and  beyond.  The  conference  was  arranged  around  three  overarching  themes:     ESD  Pedagogy:  Criticality,  Creativity,  and  Collaboration   What  are  the  teaching  and  learning  processes  that  enable  students  to  develop  their  own  capacity  to   think  critically  and  creatively  in  the  face  of  global  sustainability  challenges  and,  secondly,  to  act   collaboratively  in  ways  that  pursue  more  hopeful  and  sustainable  futures?   Innovative  Learning  Spaces  for  ESD   What  are  the  physical  environments  that  provide  opportunities  for  new  forms  of  sustainability   education  to  flourish?  What  lies  beyond  the  lecture  hall  that  is  conducive  to  student  learning  through   inquiry-­‐based,  active,  participatory,  interdisciplinary  and  experiential  methods?   Towards  the  Sustainable  University   What  are  effective  approaches  for  leading  institutional  change,  organisational  learning,  and  staff  CPD   towards  sustainability?  This  publication  focuses  on  the  last  theme  –  Towards  the  Sustainable  University.    The  previous   PedRIO  Occasional  Paper  8  looks  at  the  first  theme  ESD  Pedagogy:  Criticality,  Creativity,  and   Collaboration
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