Understanding new ways of learning in the 21st century: A preliminary study into mobile technologies

In this paper, we describe a theoretical framework and design of a study of mobile technologies in a first year university course, where students use mobile phones, or smartphones as cognitive tools. The paper describes a broader study into the use of mobile technologies with authentic learning environments, and then outlines a plan for an investigation into the nature of use of the devices in the completion of an authentic task

An empirical analysis of the cost of rearing dairy heifers from birth to first calving and the time taken to repay these costs

Rearing quality dairy heifers is essential to maintain herds by replacing culled cows. Information on the key factors influencing the cost of rearing under different management systems is, however, limited and many farmers are unaware of their true costs. This study determined the cost of rearing heifers from birth to first calving in Great Britain including the cost of mortality, investigated the main factors influencing these costs across differing farming systems and estimated how long it took heifers to repay the cost of rearing on individual farms. Primary data on heifer management from birth to calving was collected through a survey of 101 dairy farms during 2013. Univariate followed by multivariable linear regression was used to analyse the influence of farm factors and key rearing events on costs. An Excel spreadsheet model was developed to determine the time it took for heifers to repay the rearing cost. The mean +/- SD ages at weaning, conception and calving were 62 +/- 13, 509 +/- 60 and 784 +/- 60 days. The mean total cost of rearing was 1819 pound +/- 387/heifer with a mean daily cost of 2.31 pound +/- 0.41. This included the opportunity cost of the heifer and the mean cost of mortality, which ranged from 103.49 pound to 146.19 pound/surviving heifer. The multivariable model predicted an increase in mean cost of rearing of 2.87 pound for each extra day of age at first calving and a decrease in mean cost of 6.06 pound for each percentile increase in time spent at grass. The model also predicted a decrease in the mean cost of rearing in autumn and spring calving herds of 273.20 pound and 288.56 pound, respectively, compared with that in all-year-round calving herds. Farms with herd sizes100 had lower mean costs of between 301.75 pound and 407.83 pound compared with farms with <100 milking cows. The mean gross margin per heifer was 441.66 pound +/- 304.56 (range 367.63 pound to 1120.08) pound, with 11 farms experiencing negative gross margins. Most farms repaid the cost of heifer rearing in the first two lactations (range 1 to 6 lactations) with a mean time from first calving until breaking even of 530 +/- 293 days. The results of the economic analysis suggest that management decisions on key reproduction events and grazing policy significantly influence the cost of rearing and the time it takes for heifers to start making a profit for the farm

Post-Brexit implications for transboundary groundwater management along the Northern Ireland and the Republic of Ireland border

There are multiple transboundary groundwater bodies shared between Northern Ireland and the Republic of Ireland that are currently managed jointly through the EU Water Framework Directive. In 2016 the United Kingdom voted to leave the European Union and consequently, there are uncertainties regarding the future status of groundwater management between Northern Ireland and the Republic of Ireland in regards to future UK environmental policy. This paper explores the post 'Brexit' transboundary groundwater implications, if a transboundary groundwater agreement is required between Northern Ireland and the Republic of Ireland, and, should it transpire, what form should it take

Exploring students\u27 museum experiences in the context of web-based learning environments

The paper examines the nature of school excursions to museums, and how the Internet, and in particular the web pages accompanying museum exhibitions, can be utilised to create authentic and complex learning environments for school students. The paper describes proposed research between a university and two leading museums that will investigate whether and how learners link web-based content and data in developing a broader perspective on the museum experience. It will explore in depth the use of the web to situate the onsite museum visit, not as a single one-off event, but within a complex task or problem-based learning approach that extends beyond the museum visit itself

Optimal non-perfect uniform secret sharing schemes

A secret sharing scheme is non-perfect if some subsets of participants that cannot recover the secret value have partial information about it. The information ratio of a secret sharing scheme is the ratio between the maximum length of the shares and the length of the secret. This work is dedicated to the search of bounds on the information ratio of non-perfect secret sharing schemes. To this end, we extend the known connections between polymatroids and perfect secret sharing schemes to the non-perfect case. In order to study non-perfect secret sharing schemes in all generality, we describe their structure through their access function, a real function that measures the amount of information that every subset of participants obtains about the secret value. We prove that there exists a secret sharing scheme for every access function. Uniform access functions, that is, the ones whose values depend only on the number of participants, generalize the threshold access structures. Our main result is to determine the optimal information ratio of the uniform access functions. Moreover, we present a construction of linear secret sharing schemes with optimal information ratio for the rational uniform access functions.Peer ReviewedPostprint (author's final draft

Eddleston groundwater and soil moisture monitoring

This report describes work undertaken to continue monitoring at two experimental sites on the Eddleston Water, a tributary of the River Tweed. The Eddleston experimental sites were set up as part of the wider Eddleston Water Project, which aims to reduce the impact of flooding in and downstream of the village of Eddleston. The first experimental site is part of Darnhall Mains Farm, adjacent to the village of Eddleston (Ó Dochartaigh et al. 2019). It is approximately 0.2 km2 (approximately 400 m by 500 m) and covers most of the width of the Eddleston Water floodplain on both sides of the river (Figure 1). The site is farmland predominately comprising mixed livestock farming on improved grassland, but part of the floodplain has been fenced off, which has allowed trees to be planted and vegetation to recover. The monitoring at this site comprises eight boreholes in which groundwater level is recorded. The data are stored with the National Geoscience Data Centre (https://www.bgs.ac.uk/geological-data/national-geoscience-data-centre/, ID 128585). A key objective of the experimental site is to improve understanding of the role of groundwater in floodplain environments and in flooding, and of how groundwater interacts with climate, rivers and soils. The second experimental site is the Cringletie hillslope observatory (Figure 1, Peskett et al. 2020). The site is approximately 2500 m2 (approximately 50 m by 50 m) and comprises two transects parallel to the slope: one through a narrow forest strip and one on improved grassland used for mixed livestock farming (see Peskett et al. 2020). The installed monitoring equipment comprises soil moisture sensors, rain gauges and piezometers fitted with pressure transducers. The site was set up by Dr Leo Peskett as part of his PhD and was handed over to the BGS in 2020. The aim of the experimental site is to determine whether forest strips planted perpendicular to a hillslope can reduce surface runoff during flood events. Further information about the observatory is available in Peskett et al, 2020 (© 2019 Elsevier B.V. All rights reserved). In 2022/23, the BGS received funding from the Scottish Government to check the monitoring equipment; download all data and reset the loggers; replace broken equipment; and collate, process and quality check the dat

Trollthrottle -- Raising the Cost of Astroturfing

Astroturfing, i.e., the fabrication of public discourse by private or state-controlled sponsors via the creation of fake online accounts, has become incredibly widespread in recent years. It gives a disproportionally strong voice to wealthy and technology-savvy actors, permits targeted attacks on public forums and could in the long run harm the trust users have in the internet as a communication platform. Countering these efforts without deanonymising the participants has not yet proven effective; however, we can raise the cost of astroturfing. Following the principle `one person, one voice', we introduce Trollthrottle, a protocol that limits the number of comments a single person can post on participating websites. Using direct anonymous attestation and a public ledger, the user is free to choose any nickname, but the number of comments is aggregated over all posts on all websites, no matter which nickname was used. We demonstrate the deployability of Trollthrottle by retrofitting it to the popular news aggregator website Reddit and by evaluating the cost of deployment for the scenario of a national newspaper (168k comments per day), an international newspaper (268k c/d) and Reddit itself (4.9M c/d)

A conformal boundary for space-times based on light-like geodesics: the 3-dimensional case

A new causal boundary, which we will term the l-boundary, inspired by the geometry of the space of light rays and invariant by conformal diffeomorphisms for space-times of any dimension m ≥ 3, proposed by one of the authors [R. J. Low, The Space of Null Geodesics (and a New Causal Boundary), Lecture Notes in Physics 692 (Springer, 2006), pp. 35-50] is analyzed in detail for space-times of dimension 3. Under some natural assumptions, it is shown that the completed space-time becomes a smooth manifold with boundary and its relation with Geroch-Kronheimer-Penrose causal boundary is discussed.Anumber of examples illustrating the properties of this newcausal boundary as well as a discussion on the obtained results will be provided

On the Design and Implementation of an Efficient DAA Scheme

International audienceDirect Anonymous Attestation (DAA) is an anonymous digital signature scheme that aims to provide both signer authentication and privacy. One of the properties that makes DAA an attractive choice in practice is the split signer role. In short, a principal signer (a Trusted Platform Module (TPM)) signs messages in collaboration with an assistant signer (the Host, a standard computing platform into which the TPM is embedded). This split aims to harness the high level of security offered by the TPM, and augment it using the high level of computational and storage ability offered by the Host. Our contribution in this paper is a modification to an existing pairing-based DAA scheme that significantly improves efficiency, and a comparison with the original RSA-based DAA scheme via a concrete implementation