419 research outputs found
Imprinting: a comparative study of a range of avian species.
This thesis investigates the field of imprinting by comparing the behaviour of a range of precocial, nidifugous avian species, i.e. types of bird which leave their nest soon after hatching. In the first chapter literature relevant to imprinting is reviewed. A fact emerging from this review is the lack of comparability between various imprinting experiments. In this thesis the importance of experimental uniformity is stressed. It had been thought by Lorenz: (1935) that some species of wader, i.e. curlews (Numenius arquata), and godwits (Limosa limosa), could not imprint on an inappropriate stimulus. This suggestion was investigated in the present comparative study in which, for the species studied, the experimental method was kept uniform. In the second chapter the experimental method is described as is the type of species and the taxonomic group from which they come. The species used were: the domestic fowl; pheasant; partridge; wild mallard; curlew; lapwing and oyster-catcher. The stimulus used to encourage approach from these species was a rotating, white disc, with a 45 red sector. In the third chapter, four experiments are described. In the first three experiments the effects of various stimuli and training procedure in imprinting, were investigated using domestic fowl. This was done in order to examine the effectiveness of the stimuli in inducing approach. The fourth experiment compared a range of species responses to a combined visual and auditory stimulus. In chapter five, two further experiments are described which were conducted on lapwings, extending the generality of conclusions from experiment four. Chapter six contains the conclusions drawn from the experiments, and the need to consider the natural parent-chick bond is stressed
Advanced Multiphysics Modeling of Solar Tower Receivers Using Object-oriented Software and High Performance Computing Platforms
AbstractThis paper presents an advanced methodology for the detailed modeling of the heat transfer and fluid dynamics phenomena in solar tower receivers. It has been carried out in the framework of a more ambitious enterprise which aims at modeling all the complex heat transfer and fluid dynamics phenomena present in central solar receivers. The global model is composed of 4 sub-models (heat conduction, two-phase flow, solar and thermal radiation and natural convection) which are described. Results of the numerical model obtained so far are also presented and discusse
Barcelona SMARTMOTO CHALLENGE
In this paper we present the rules of the first edition of the SMARTMOTO
CHALLENGE, www.smartmotochallenge.org . It will take place during the 2012-2013
season, showing the vehicles in July 2013 at the ParcMotor of Igualada and in
Barcelona City. This is a competition of an electric motorcycle development where
students, from participating universities, must make an electric motorcycle in
accordance with the rules that we expose here.
Following the successful example in the automotive industry with the Formula SAE,
started in the USA, and now in full expansion in Europe with the Formula Student, we
want to launch an Spanish but international competition oriented to the light electrical
bikes.Postprint (published version
Finding a widest empty 1-corner corridor
Given a set of n points in the plane, we consider the problem of computing a widest empty 1-corner corridor. We star giving a characterization of the 1-corner corridors that we call locally widest. Our approach to finding a
widest empty 1-corner corridor consists of identifying a set of 1-corner corridors locally widest, that is guaranteed to contain a solution. We describe an algorithm that solves the problem in O(n4 log n) time and O(n) space.Ministerio de Ciencia y TecnologĂaNational Science FoundationGeneralitat de Cataluny
Trebouxia lynnae sp. nov. (former Trebouxia sp. TR9): biology and biogeography of an epitome lichen symbiotic microalga
Two microalgal species, Trebouxia jamesii and Trebouxia sp. TR9, were detected as the main photobionts coexisting in the thalli of the lichen Ramalina farinacea. Trebouxia sp. TR9 emerged as anew taxon in lichen symbioses and was successfully isolated and propagated in in vitro culture andthoroughly investigated. Several years of research have confirmed the taxon Trebouxia sp. TR9 tobe a model/reference organism for studying mycobiont–photobiont association patterns in lichensymbioses. Trebouxia sp. TR9 is the first symbiotic, lichen-forming microalga for which an exhaustivecharacterization of cellular ultrastructure, physiological traits, genetic and genomic diversity is available.The cellular ultrastructure was studied by light, electron and confocal microscopy; physiologicaltraits were studied as responses to different abiotic stresses. The genetic diversity was previouslyanalyzed at both the nuclear and organelle levels by using chloroplast, mitochondrial, and nucleargenome data, and a multiplicity of phylogenetic analyses were carried out to study its intraspecificdiversity at a biogeographical level and its specificity association patterns with the mycobiont.Here, Trebouxia sp. TR9 is formally described by applying an integrative taxonomic approach and ispresented to science as Trebouxia lynnae, in honor of Lynn Margulis, who was the primary modernproponent for the significance of symbiosis in evolution. The complete set of analyses that werecarried out for its characterization is provided
Development of Conductivity Sensors for Multi-Phase Flow Local Measurements at the Polytechnic University of Valencia (UPV) and University Jaume I of Castellon (UJI)
[EN] This paper describes all the procedures and methods currently used at UPV (Universitat Politécnica de Valencia) and UJI (University Jaume I) for the development and use of sensors for multi-phase flow analysis in vertical pipes. This paper also describes the methods that we use to obtain the values of the two-phase flow magnitudes from the sensor signals and the validation and cross-verification methods developed to check the consistency of the results obtained for these magnitudes with the sensors. First, we provide information about the procedures used to build the multi-sensor conductivity probes and some of the tests performed with different materials to avoid sensor degradation issues. In addition, we provide information about the characteristics of the electric circuits that feed the sensors. Then the data acquisition of the conductivity probe, the signal conditioning and the data processing including the device that have been designed to automatize all the measurement process of moving the sensors inside the channels by means of stepper electric motors controlled by computer are shown in operation. Then, we explain the methods used for bubble identification and categorization. Finally, we describe the methodology used to obtain the two-phase flow information from the sensor signals. This includes the following items: void fraction, gas velocity, Sauter mean diameter and interfacial area concentration. The last part of this paper is devoted to the conductance probes developed for the annular flow analysis, which includes the analysis of the interfacial waves produced in annular flow and that requires a different type of sensorThe authors are indebted to the support received from MINECO for the project MODEXFLAT ENE2013-48565-C2-1-P and ENE2013-48565-C2-2-P.Muñoz-Cobo, JL.; Chiva, S.; Mendez, S.; Monrós, G.; Escrivá, A.; Cuadros-Orón, JL. (2017). Development of Conductivity Sensors for Multi-Phase Flow Local Measurements at the Polytechnic University of Valencia (UPV) and University Jaume I of Castellon (UJI). Sensors. 17(5):1-35. https://doi.org/10.3390/s17051077S13517
Characterization of the gas-liquid interfacial waves in vertical upward co-current annular flows
[EN] For more than fifty years, hundreds of research works have focused on the study of annular flow because of its huge importance in many industrial processes, for instance, chemical, petroleum, etc., being of particular interest in nuclear industry. Specifically, interfacial waves play a vital role in the mass, momentum and energy transference processes between gas and liquid phases. This paper describes the new experimental measurements of vertical upward co-current two-phase gas-liquid flow carried out in a tube with an inner diameter of 44 mm. The liquid film thickness and the major characteristics of the interfacial waves have been measured using a non-intrusive instrument, a conductance probe. The physical phenomenon in which this device is based is the change in the electrical conductivity between air and water, i.e., the electrical signal collected in the sensor receiver depends on the thickness of the liquid film layer. The experimental measurements range from 2000 to 3500 l/min for the gas volumetric flow rate, and from 4 to 10 l/min for the liquid volumetric flow rate. Correlation of the experimental measurements of liquid film thickness and the major properties of the interfacial waves have been analyzed using non-dimensional numbers. An important part of the document focuses on the comparison of the experimental data and the fitting correlations against several of the most widely used expressions. Throughout this paper, in addition to present all the available correlations, the existing scattering found when comparing against other expressions have been also confirmed, underlining the existence of gaps of knowledge even today. Emphasize that the proposed correlations are the ones that better fit the data of all experimental series carried out under the present study for the analyzed variables, with almost all the experimental points covered by the +/- 10% error bands of the new correlations.The authors are indebted to the plan of I+D support of the EXMOTRANSIN project ENE2016-79489-C2-1-P.Cuadros-Orón, JL.; Rivera-Durán, Y.; Berna, C.; Escrivá, A.; Muñoz-Cobo, JL.; Monrós-Andreu, G.; Chiva, S. (2019). Characterization of the gas-liquid interfacial waves in vertical upward co-current annular flows. Nuclear Engineering and Design. 346:112-130. https://doi.org/10.1016/j.nucengdes.2019.03.008S11213034
Unilateral Ovarian Abscess Caused by Salmonella
Background: Patients with unilateral ovarian abscesses due to Salmonella are rare. Case report: A 48-year-old woman with a left ovarian abscess caused by Salmonella group O7 is reported. Conclusion: In our patient, the ovary may have been seeded hematogenously by salmonellae and may have evolved into a local infection
SUCCOR Nodes: May Sentinel Node Biopsy Determine the Need for Adjuvant Treatment?
Background
The SUCCOR cohort was developed to analyse the overall and disease-free survival at 5 years in women with FIGO 2009 stage IB1 cervical cancer. The aim of this study was to compare the use of adjuvant therapy in these women, depending on the method used to diagnose lymphatic node metastasis.
Patients and Methods
We used data from the SUCCOR cohort, which collected information from 1049 women with FIGO 2009 stage IB1 cervical cancer who were operated on between January 2013 and December 2014 in Europe. We calculated the adjusted proportion of women who received adjuvant therapy depending on the lymph node diagnosis method and compared disease free and overall survival using Cox proportional-hazards regression models. Inverse probability weighting was used to adjust for baseline potential confounders.
Results
The adjusted proportion of women who received adjuvant therapy was 33.8% in the sentinel node biopsy + lymphadenectomy (SNB+LA) group and 44.7% in the LA group (p = 0.02), although the proportion of positive nodal status was similar (p = 0.30). That difference was greater in women with negative nodal status and positive Sedlis criteria (difference 31.2%, p = 0.01). Here, those who underwent a SNB+LA had an increased risk of relapse [hazard ratio (HR) 2.49, 95% confidence interval (CI) 0.98–6.33, p = 0.056] and risk of death (HR 3.49, 95% CI 1.04–11.7, p = 0.042) compared with those who underwent LA.
Conclusions
Women in this study were less likely to receive adjuvant therapy if their nodal invasion was determined using SNB+LA compared with LA. These results suggest a lack of therapeutic measures available when a negative result is obtained by SNB+LA, which may have an impact on the risk of recurrence and survival
Older workers in the hospitality industry: valuing experience and informal learning
The research sets out to identify the learning processes adopted by older workers in the hospitality and visitor attraction industry in Scotland, with a view to determining how employers may better support their education and training within enterprises. The study was undertaken as part of the ESRC project on ‘sustaining the employability of older workers in the hospitality sector: personal learning strategies and cultures of learning. The data collection period was from 2008-2010 and focused on six case studies; three in hospitality and three visitor attraction centres. The conceptual framework of the research is based upon the simple yet important notion of experience and how this enhances the learning lives of older employees. It will be argued that the learning processes used by older employees are primarily recognisable as social practices, based upon the utilisation of existing knowledge and skills. The analysis suggests that organisations should be encouraged to avoid using a ‘one size fits all’ approach to education and training and, in the case of older workers, to make more use of their past work and life experiences in order to facilitate their own and others’ learning
- …