326 research outputs found

    An Inquiry-Infused Introductory Biology Laboratory That Integrates Mendel\u27s Pea Phenotypes With Molecular Mechanisms

    Get PDF
    We developed a multi-week laboratory in which college-level introductory biology students investigate Mendel\u27s stem length phenotype in peas. Students collect, analyze and interpret convergent evidence from molecular and physiological techniques. In weeks 1 and 2, students treat control and experimental plants with Gibberellic Acid (GA) to determine whether uncharacterized short mutant lines are GA responsive. These data allow students to place the mutation in the GA signal transduction pathway. During weeks 2 and 3, plants are genotyped for Mendel\u27s le mutation using a derived cleaved polymorphic sequences (dCAPS) PCR assay. This laboratory allows students to make a direct connection between modern molecular genetics and the easily scored phenotypes Mendel used as the basis of his fundamental discoveries. We administered surveys to assess student gains in accord with four learning goals: understanding the lab, basic science literacy, scientific practices, and working collaboratively. Student confidence increased significantly in the first three, but not in working collaboratively, although students reported greater confidence working in groups than alone

    BS-ISO helical gear fatigue life estimation and wear quantitative features analysis

    Get PDF
    Original article can be found at: http://www3.interscience.wiley.com/ Copyright Blackwell Publishing. DOI: 10.1111/j.1475-1305.2008.00457.xLack of representative theoretical models for gear wear causes difficulties in their useful lifetime prediction. Critical operating parameters, such as loading and lubrication, affect the wear process in a very complex manner and lead the theoretical modelling to an imperfect zone of assumptions. Complexities in gear wear mathematical modelling allow the researchers to use approximations for useful lifetime calculations. On the basis of modelling approximations and assumptions, organizations, such as American Gear Manufacturers' Association (AGMA) and British Standards (BS), provide gear useful lifetime formulations. In these formulations, the useful lifetime values are estimated by means of experimentation that is controlled with known gear operating conditions and physical dimensions. However, for useful lifetime estimation and validation, these standards have not considered any experimental approach that represents the actual gear wear. In this paper, an effort is made to validate the competency of standard's gear useful lifetime formulation. For this purpose, an approach that is able to provide an idea about actual gear wear is used. During the effort, BS-ISO 6336-2 standard formulation is used for helical gear useful lifetime estimation under linear pitting fatigue conditions. The used formulation is validated by using wear quantitative feature analysis that is able to provide actual gear wear quantitative trends. The obtained wear quantitative trends fairly validate the lifetime estimation of BS-ISO 6336-2 standard.Peer reviewe

    House as Mediator: Integrative Typology as Connector Between Land and Sea

    Get PDF
    Rather than the water being an obstacle to coastal residential communities, water can act as an opportunity. Instead of barricading these areas from the water, integrating it with the area would create communities that are capable of living in unison with the ocean. This can introduce new typologies of housing that can withstand the continuing rise of sea levels. Blurring the line between land and sea by living with the sea will allow coastal regions to stay afloat, benefiting from ever-changing water conditions. A proposed new housing typology would introduce a new program to coastal neighborhoods, rather than putting up walls. Interacting with the coastal region instead of barricading a community from it, would allow a new housing type to promote publicness

    John Lyly’s Anatomy of Wit as an Example of Early Modern Psychological Fiction

    Get PDF
    John Lyly developed the prose style that would become known as euphuism, named after the main character in his Euphues: The Anatomy of Wit (1578) and Euphues and his England (1580). The term ‘euphuism’ signifies the use of paradoxical and self-correcting language, while its spokespersons express a great deal of self-doubt and contradiction. We can conjecture that Lyly intended his ironic, detailed examination of ‘wit’ to dissect both the intellect and its often-inconsistent maneuverings, revealing a cynical view of human behavior. In this article, I re-read The Anatomy of Wit (1578) in the context of a larger body of what I call proto-psychological fiction. I argue that certain Early Modern texts, of which Lyly’s is a strong example, share tropes and motifs that indicate the author’s interest in the workings of human psychology avant la lettre, and more specifically, of a pessimistic strain of thought that is critical of self-awareness and doubtful of our ability to be guided by reason

    Fracture Mechanics Based Models of Structural and Contact Fatigue

    Get PDF

    Active Learning Outside The Classroom: Implementation And Outcomes Of Peer-Led Team-Learning Workshops In Introductory Biology

    Get PDF
    Study group meetings (SGMs) are voluntary-attendance peer-led team-learning workshops that supplement introductory biology lectures at a selective liberal arts college. While supporting all students’ engagement with lecture material, specific aims are to improve the success of underrepresented minority (URM) students and those with weaker backgrounds in biology. Peer leaders with experience in biology courses and training in science pedagogy facilitate work on faculty-generated challenge problems. During the eight semesters assessed in this study, URM students and those with less preparation attended SGMs with equal or greater frequency than their counterparts. Most agreed that SGMs enhanced their comprehension of biology and ability to articulate solutions. The historical grade gap between URM and non-URM students narrowed slightly in Biology 2, but not in other biology and science, technology, engineering, and mathematics courses. Nonetheless, URM students taking introductory biology after program implementation have graduated with biology majors or minors at the same rates as non-URM students, and have enrolled in postcollege degree programs at equal or greater rates. These results suggest that improved performance as measured by science grade point average may not be necessary to improve the persistence of students from underrepresented groups as life sciences majors

    Body Anatomical UV Protection Predicted by Shade Structures: A Modeling Study.

    Get PDF
    Shade is an important means of protection against harmful effects of sun ultraviolet (UV) exposure, but not all shades are identically protective. UV rays scattered by the atmosphere and surroundings can reach the skin indirectly. To evaluate the relative contribution of the direct, diffuse, and reflected radiation in UV protection provided by different sizes of shade structure, we used SimUVEx v2, a numeric tool based on 3D graphic techniques and ambient ground UV irradiance. The relative UV exposure reduction was expressed by the predictive protection factor (PPF). Shade structures were found to predominantly reduce exposure from direct radiation (from 97.1% to 99.9% for the upper body areas such as the head and the neck), with greater protection from larger shade structures and structures closer above the subject. Legs were the least protected anatomical zone from any shade structure above the subject with PPF ranging from 18.5% to 68.1%. Throughout the day, except for lower solar zenith angles (SZA), small and high shade structures provide the lowest protection (between 20% and 50%), while small and low shade structure show PPF between 35% and 65% and large and high shade structures reach PPF higher than 60%

    Validation of a method to estimate direct normal irradiance of UVA and PAR bands from global horizontal measurements for cloudless sky conditions in Valencia, Spain, by a measurement campaign

    Full text link
    A method is proposed to provide measurement of direct normal solar irradiance of bands with wavelength ranges (315-400 nm, 400-700 nm) from measurements of global horizontal band irradiance for cloudless sky conditions in Valencia. Global and normal direct irradiance data for every air mass were obtained by applying the SMART2 model to the atmosphere of Valencia. The direct normal to global irradiance ratio was parameterized versus the relative optical air mass. A measurement campaign of global horizontal and diffuse irradiance of UVA and PAR bands was carried out in Valencia, after which, the inferred direct normal irradiance was compared with those provided by the method. The result of the comparison shows that the method is acceptably accurate. The proposed model tends to underestimate the direct normal irradiance of the UVA band by 6%, although for values below 25 W/m2 the model overestimates the direct irradiance by 6%, while for values above 25 W/m2 the model underestimates it by 10%. The other two error estimators used ranging from 11% to 15% are similar in the defined interval measurements in relation to the whole UVA band. Regarding the PAR band, the model overestimates the direct normal irradiance of the PAR band by only 2.2%. With this, the results of the PAR band are more conclusive, as it has been found that for direct normal irradiance values higher than 280 W/m2 the MBE error is almost zero and the other two estimator errors are small, about 5%. © 2010 Springer-Verlag.This work was supported by the Spanish Government through MEC grant MAT2009-14625-C03-03, and is a part of the activities of the Grup d'Optoelectronica i Semiconductors of the Polytechnic University of Valencia. The translation of this paper was funded by the Universidad Politecnica de Valencia, Spain.Serrano Jareño, MA.; BoscĂĄ Berga, JV. (2011). Validation of a method to estimate direct normal irradiance of UVA and PAR bands from global horizontal measurements for cloudless sky conditions in Valencia, Spain, by a measurement campaign. Theoretical and Applied Climatology. 103(1):95-101. https://doi.org/10.1007/s00704-010-0284-9S951011031Barth J, Cadet J, CĂ©sarini JP, Fitzpatrick TB, McKinlay A, Mutzhas M, Pathak M, Peak M, Sliney D, Urbach F (1999) TC 6-26 report: Standardization of the terms UV-A1, UV-A2 and UV-B, CIE 134-1999 ISBN 3-900-734-94-1Batlles FJ, Olmo FJ, Alados-Arboledas L (1995) On shadowband correction methods for diffuse irradiance measurements. Solar Energy 54(5):105–114Drummond AJ (1956) On the measurement of sky radiation. Arch 602 Meteor Geophys Bioklim B 7:413–436Gueymard C (1995) SMARTS2: a simple model of the atmospheric radiative transfer of sunshine: algorithms and performance assessment. FSEC-PF-270-95, Florida Solar Energy CenterGueymard C (2003) SMARTS2 code, versiĂłn 2.9.2. User’s Manual, Solar Consulting Services Bailey CO. Available from http://rredc.nrel.gov/solar/models/SMARTS/smarts_index.htmlGueymard C (2004) The sun’s total and spectral irradiance for solar energy applications and solar radiation models. Solar Energy 76:423–453HĂ€der DP, Lebert M, Marangoni R, Colombetti G (1999) ELDONET-European light dosimeter network hardware and software. J Photochem Photobiol B: Biol 52:51–58HĂ€der DP, Lebert M, Colombetti G, Figueroa F (2001) European light dosimeter network (ELDONET). Helgol Mar Res 55:35–44Iqbal M (1983) An introduction to solar radiation. Academic, TorontoKudish AI, Evseev EG (2008) The assessment of four different correction models applied to the diffuse radiation measured with a shadow ring using global and normal beam radiation measurements for Beer Sheva, Israel. Solar Energy 82(2):144–156LeBaron BA, Michalsky JJ, Perez R (1990) A simple procedure for correcting shadowband data for all sky conditions. Solar Energy 44:249–256MarĂ­n FernĂĄndez MJ (2007) Estudio de la irradiancia solar ultravioleta y eritemĂĄtica en la Comunidad Valenciana. Doctoral Thesis University of Valencia (Spain)Perez R, Ineichen P, Seals R, Michalsky JJ, Stewart R (1990) Modelling daylight availability and irradiance components from direct and global irradiance. Sol Energy 44:271–289Pinazo JM, Cañada J, Bosca JV (1995) A new method to determine Ångström's turbidity coefficient: its application for Valencia. Solar Energy 54:219–226Serrano MA, BoscĂĄ JV, Cañada J (2008) The determination of a band factor to express irradiance of UV and PAR wavelength ranges in a clean and dry atmosphere at Valencia (Spain). Int J Ambient Energy 29(4):171–180Utrillas MP, BoscĂ  JV, Martinez-Lozano JA, Cañada J, Tena F, Pinazo JM (1998) A comparative study of Spectral2, and Smarts2 parameterised models based on spectral irradiance measurements at Valencia, Spain. Solar Energy 63:161–171Utrillas MP, MarĂ­n MJ, Esteve AR, Tena F, Cañada J, EstellĂ©s V, MartĂ­nez Lozano JA (2007) Diffuse UV erythemal radiation experimental values. J Geophy Res 112:387–39

    Shadow-band radiometer measurement of diffuse solar irradiance: Calculation of geometrical and total correction factors

    Get PDF
    Among the various methods of measuring diffuse solar irradiance, shadowing devices are ones of the most commonly used in solar research all over the world. These instruments work with a basic pyranometer, properly calibrated for the measurement of solar irradiance, with a shadowing element, which can be a disk or a band (Drummond’s shadow-band), that prevents the direct incidence of solar beam irradiance on the sensor. This method is capable of precise measurements, but sensor outputs have to be corrected, so as to quantify the amount of diffuse irradiance that the band blocks from reaching the sensor. Several authors have advanced different expressions for this correction factor, most of which only apply to horizontal and equator-oriented tilting pyranometers. In this work, we present a general approach to calculate the geometrical correction factor for a tilted sensor, oriented towards all possible azimuth and zenith angles, which permits the measurement of solar diffuse irradiance on any tilted and oriented surfaces. Furthermore, five total correction models are adapted for measurement in any given direction and evaluated on vertical walls pointing the four cardinal directions. Our results show that geometrical correction improves the Mean Bias Difference (MBD), the Root Mean Squared Difference (RMSD) and the l0:99 statistics by 60%, 62% and 56%, respectively, in contrast with the raw data. The LeBaron et al. model gives the most accurate figure for total correction according to MBD, RMSD and l0:99 statistics, with promising average performances of 97%, 91%, and 96%, respectivelySpanish Government (grant ENE2011-27511

    Selection of cloudless sky conditions by applying solar globalultraviolet irradiance measurements

    Full text link
    Taking advantage of UV (295 385 nm) irradiance measurements is one of the objectives of this paper. A newindex termed kt″ is established for this band. This newindexworks as a zenith angle independent clearness index for band measurements and has similar applications to those of kt′ for broadband measurements. The new index may be applied to identify cloudless instants from UV band measurements. Both indexes were correlated throughout the period 1998 2004 with a R2 of 0.85. A selection criterion of kt″UV >1.1 classified cloudless sky conditions with a probability of 95% in comparison with a selection that two criteria-applying broadband measurements would make. This index may be of interest for classifying cloudless sky conditions when only UV band measurements are available. An estimation method from the literature was applied to the period 1998 2004. This method was previously validated for the UV band with a measurement campaign made in Valencia (Spain) in the summer season.This work was supported by the Spanish Government through MEC grant MAT2006-02279, and was a part of the activities of the Grup d'Optoelectronica i Semiconductors of the Universitat Politecnica de Valencia, Spain.Serrano, M.; BoscĂĄ Berga, JV. (2013). Selection of cloudless sky conditions by applying solar globalultraviolet irradiance measurements. Atmospheric Research. 132-133:291-298. https://doi.org/10.1016/j.atmosres.2013.05.020S291298132-13
    • 

    corecore