Multilingual media components directly embeddable in open educational resources in science and technology

The use and reuse of OER (Open Educational Resources) depends on several conditions. Amongst others, the richness of their metadata, their granularity and the languages ​​in which they are made available. This work aims to facilitate efficient production of graphical and language-neutral components. It is assumed that the STEM areas (Science, Technology, Engeneering and Mathematics) share a common mathematical language and, more intuitively, an iconographic approach linked to the structures that satisfy the formulas used in each case. The work is limited to these areas of knowledge, primarily as presentations and animations of very low granularity, which can be directly integrated into larger resources in any language. The overall research design consists of four stages: 1. Initially, the manual generation of presentations and animations, with no literal in any language, and very concisely focused (mainly, definitions of a single concept for each animation). Determination of common graphics primitives to differentiate the common subtasks: presentation of examples to make the concept emerge inductively, graphical construction of the definition, highlighting the generalization or instantiation steps, homogeneous use of icons for emphasising or posing a question to the observer .. . 2. Evaluation of the expressiveness and effectiveness of these resources. Currently, these resources are being presented to small groups of students. This fall begins a multilingual evaluation process on a larger scale: as part of a regular course at the UNED and as LabSpace course in the Open University. Here we attempt to clarify the appropriate assessment tools (preferably in the same graphics language) with the minimum amount of additional external comments to constitute a course in a particular language. 3. The first two stages must provide an intuitive and graphical interface of the selected formalism (mainly Discrete Mathematics and Logic). The third stage addresses the effect of changing the output device on the selection of the graphics primitives for each generic subtask. Possible variations of the graphical language will be studied in the context of HCI analyses. 4. Finally the approach addresses semi-automatic generation, via script, of these resources: from formal description of the definitions or processes (as described, for example, in OMDoc) to the production of the corresponding animation. Additionally, the injection of semantics should facilitate the link between different animations, the navigation and search of conceptual dependency and the identification of concepts that have supporting collections of resources as described. At this point, the current development of this work provides results for the first two stages described

Stirring and transport enhancement in a continuously modulated free-surface flow

The transport of fluid from a recirculation region adjacent to a free surface is studied using a numerical method validated with experimental flow visualization. The flow is an example of a liquid film coating process, and consists of two counter-rotating rolls placed side-by-side and half-submerged in a bath of fluid. In the gap between the rolls a recirculation zone exists just below the free surface, around which the flow splits into two films. Fluid recirculating for long periods has been identified as a source of coating defects, so this paper considers a possible method of inducing stirring. The flow is modulated by driving one of the rolls through a Hooke's joint, which delivers a well-characterized periodic perturbation to the roll speed. In response to this speed modulation, the free surface undergoes a periodic change in position and shape which drives an exchange of fluid between the recirculation region and the surrounding flow. The amplitude of the free-surface motion is strongly dependent on modulation frequency. The dynamics of the free surface preclude a quasi-steady approach, even in the small-frequency limit, and so a fully time-dependent analysis based on the finite element method is employed. Trigonometric temporal interpolation of the finite element data is used to make passive tracer advection calculations more efficient, and excellent agreement is seen between simulation and experiment. Computations of the stable and unstable invariant manifolds associated with periodic points on the free surface reveal that the exchange of fluid is governed by a self-intersecting turnstile mechanism, by which most fluid entrained during a modulation cycle is ejected later in the same cycle. Transport over several cycles is explored by observation of the evacuation of passive tracers initially distributed uniformly in the recirculation zone. Results demonstrate the persistence of unmixed cores whose size is dependent on the modulation frequency. By considering the percentage of tracers remaining after a fixed number of cycles, contours in frequency-amplitude space show that for each modulation amplitude there is a frequency which produces the most effective transport, with up to 80 % of tracers removed by a modulation which produces only a 5 % change in film thickness. Finally it is shown how modulation of both rolls at slightly different phases can reduce the film thickness variation to about 1 % while maintaining the level of transport

A measure of conductivity for lattice fermions at finite density

We study the linear response to an external electric field of a system of fermions in a lattice at zero temperature. This allows to measure numerically the Euclidean conductivity which turns out to be compatible with an analytical calculation for free fermions. The numerical method is generalizable to systems with dynamical interactions where no analytical approach is possible.Comment: version to be published in Physics Letters

Elite male Flat jockeys display lower bone density and lower resting metabolic rate than their female counterparts: implications for athlete welfare

To test the hypothesis that daily weight-making is more problematic to health in male compared with female jockeys, we compared the bone-density and resting metabolic rate (RMR) in weight-matched male and female Flat-jockeys. RMR (kcal.kg-1 lean mass) was lower in males compared with females as well as lower bone-density Z-scores at the hip and lumbar spine. Data suggest the lifestyle of male jockeys’ compromise health more severely than females, possibly due to making-weight more frequently

Design of Agriculture Drainage Under Uncertainty: 1. Background and Chance Constraint Approach

The problems of waterlogging and salinity on agricultural lands has led to the installation of agricultural drainage systems. The effect of soil property uncertainty on drainage system design and thus drain performance is not implicitly considered by present design procedures. This is the first in a series of papers that will present methods for analyzing the effect of soil property uncertainty on drainage system design. An analysis of the nature of uncertainty and spatial variability in recharge rate and soil permeability is presented. A First Order--Second Moment (FOSM) approach is developed for the Hooghoudt steady-state drainage design equation to provide an estimate of the of the uncertainty of the dewatering zone between the drains as a function of the design variables and the uncertainty in the soil properties. Based upon the FOSM approach, a Chance Constraint model for optimal design of drains is developed which incorporates uncertainty in recharge rate, permeability, dewatering zone with the economics of drain installation to provide the least cost design for given reliabilities of drain performance

Design of Agriculture Drainage Under Uncertainty: 2. A Stochastic Programming Approach

The effect of soil property uncertainty on drainage system design was presented in the first of a series of papers on methods for optimal design of agricultural drains. A First Order--Second Moment (FOSM) approach was developed for the Hooghoudt steady-state drainage design ,equation to provide an estimate of the of the uncertainty of the dewatering zone between the drains as a function of the design variables and the uncertainty in the soil properties. In this paper, a Stochastic Programming Model for optimal design of drains under uncertainty, based upon the FOSM approach, is developed. The Stochastic Programming Model incorporates uncertainty in the objective function of the model as the expected loss in crop production as a function of uncertainty in the dewatering zone. The Stochastic Programming model is extended to included a multiple cropping situation and finally, the Chance Constraint approach, presented in the first paper, is compared with the Stochastic Programming Approach to drainage design and advantages of each are presented

Phaeochrornocytorna - a case report

A 52-year-old man presented with a 4-year history of paroxysmal attacks of anxiety, giddiness, palpitation, sweating, and severe headache. These symptoms wereassociated with sudden increases in his blood pressure; and a provisional diagnosis of phaeochromocytoma was made.Collections of urine were submitted for catecholamine assay. One collection showed a slight increase in catecholamines but the rest were normal, including a collection made after a provocation test, using histamine 0,025 mg intravenously. The histamine test did, however, cause systolic and diastolic blood pressure to rise by 20 mmHg.As he was mildly hypertensive between paroxysms, a phentolamine test was carried out, utilising 5 mg well diluted, intravenously, over 5 minutes under basal conditions. This, too, was negative. An aortogram failed to demonstrate convincingly tumour vascularisation, but there was a mild hypertensive crisis during this examination.At laparotomy, a single phaeochromocytoma was found in the right adrenal gland, and was successfully removed. Recovery was uneventful and the patient was discharged, normotensive and not requiring hypotensive therapy, though mild hypertension has developed since. No residual catecholamine activity has been detected.The preparation of the patient for surgery and the control of operative complications are described, and the salient diagnostic features of phaeochromocytoma are briefly discussed.S. Afr. Med. J. 48, 401 (1974)

Development of real-time PCR and hybridization methods for detection and identification of thermophilic Campylobacter spp. in pig faecal samples

Aims: To develop a real-time (rt) PCR for species differentiation of thermophilic Campylobacter and to develop a method for assessing co-colonization of pigs by Campylobacter spp. Methods and results: The specificity of a developed 5’nuclease rt-PCR for species-specific identification of C. jejuni, C. coli, C. lari, C. upsaliensis and of a hipO gene nucleotide probe for detection of C. jejuni by colony-blot hybridization were determined by testing a total of 75 reference strains of Campylobacter spp. and related organisms. The rt-PCR method allowed species-specific detection of Campylobacter spp. in naturally infected pig faecal samples after an enrichment step, whereas the hybridization approach enhanced the specific isolation of C. jejuni (present in minority to C. coli) from pigs. Conclusions: The rt-PCR was specific for Campylobacter jejuni, C. coli, C. lari, and C. upsaliensis and the colony-blot hybridization approach provided an effective tool for isolation of C. jejuni from pig faecal samples typically dominated by C. coli. Significance and impact of study: Species differentiation between thermophilic Campylobacter is difficult by phenotypic methods and the developed rt-PCR provides an easy and fast method for such differentiation. Detection of C. jejuni by colony hybridization may increase the isolation rate of this species from pig feces