Student conceptions about energy transformations: progression from general chemistry to biochemistry

Students commencing studies in biochemistry must transfer and build on concepts they learned in chemistry and biology classes. It is well established, however, that students have difficulties in transferring critical concepts from general chemistry courses; one key concept is “energy.” Most previous work on students’ conception of energy has focused on their understanding of energy in the context of physics (including the idea of “work”) and/or their understanding of energy in classical physical and inorganic chemistry contexts (particularly Gibbs Free Energy changes, the second law of thermodynamics, and equilibrium under standard conditions within a closed system). For biochemistry, students must go beyond those basic thermodynamics concepts of work, standard energy changes, and closed systems, and instead they must consider what energy flow, use, and transformation mean in living, open, and dynamic systems. In this study we explored students’ concepts about free energy and flow in biological chemical reactions and metabolic pathways by surveys and in-depth interviews. We worked with students in general chemistry classes and biochemistry courses in both an Australian and a US tertiary institution. We address three primary questions (i) What are the most common alternative conceptions held by students when they explain energy-related phenomena in biochemistry?, (ii) What information do students transfer from introductory chemistry and biology when they are asked to consider energy in a biological reaction or reaction pathway?, and (iii) How do students at varying levels of competence articulate their understandings of energy in pathways and biological reactions? The answers to these questions are used to build a preliminary learning progression for understanding “energy” in biochemistry. We also propose crucial elements of content knowledge that instructors could apply to help students better grasp this threshold concept in biochemistry

Key Topics on End-of-Life Care for African Americans

Racial classifications of human populations are politically and socially determined. There is no biological or genetic basis for these racial classifications. Health behaviors may be influenced by culture and poverty. Disparities in health outcomes, sometimes resulting in higher mortality rates for African-Americans appear to influence end of life decision-making attitudes and behaviors. To improve the quality of end of life care in African-American communities, health care professionals must better understand and work to eliminate disparities in health care, increase their own skills, knowledge and confidence in palliative and hospice care, and improve awareness of the benefits and values of hospice and palliative care in their patients and families

Very Low-mass Stellar and Substellar Companions to Solar-like Stars from MARVELS II: A Short-period Companion Orbiting an F Star with Evidence of a Stellar Tertiary And Significant Mutual Inclination

We report the discovery via radial velocity of a short-period (P = 2.430420 \pm 0.000006 days) companion to the F-type main sequence star TYC 2930-00872-1. A long-term trend in the radial velocities indicates the presence of a tertiary stellar companion with $P > 2000$ days. High-resolution spectroscopy of the host star yields T_eff = 6427 +/- 33 K, log(g) = 4.52 +/- 0.14, and [Fe/H]=-0.04 +/- 0.05. These parameters, combined with the broad-band spectral energy distribution and parallax, allow us to infer a mass and radius of the host star of M_1=1.21 +/- 0.08 M_\odot and R_1=1.09_{-0.13}^{+0.15} R_\odot. We are able to exclude transits of the inner companion with high confidence. The host star's spectrum exhibits clear Ca H and K core emission indicating stellar activity, but a lack of photometric variability and small v*sin(I) suggest the primary's spin axis is oriented in a pole-on configuration. The rotational period of the primary from an activity-rotation relation matches the orbital period of the inner companion to within 1.5 \sigma, suggesting they are tidally locked. If the inner companion's orbital angular momentum vector is aligned with the stellar spin axis, as expected through tidal evolution, then it has a stellar mass of M_2 ~ 0.3-0.4 M_\odot. Direct imaging limits the existence of stellar companions to projected separations < 30 AU. No set of spectral lines and no significant flux contribution to the spectral energy distribution from either companion are detected, which places individual upper mass limits of M < 1.0 M_\odot, provided they are not stellar remnants. If the tertiary is not a stellar remnant, then it likely has a mass of ~0.5-0.6 M_\odot, and its orbit is likely significantly inclined from that of the secondary, suggesting that the Kozai-Lidov mechanism may have driven the dynamical evolution of this system.Comment: 37 pages, 7 tables, 21 figures, Accepted in A

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Work of Frank Lloyd Wright

Architectural projects and/or sites mentioned: H. W. Bassett House (Frank Lloyd Wright, 1894) (Oak Park, Illinois) ; Charles E. Roberts House (Frank Lloyd Wright, 1896) (Oak Park, Illinois) ; Quadruple Block Plan (unbuilt) (Frank Lloyd Wright, 1901) ; Robie House (Frank Lloyd Wright, 1908-1910) (Chicago, Illinois) ; Plan of Chicago (Daniel Hudson Burnham, 1909) (Chicago, Illinois) ; Taliesin (Frank Lloyd Wright, 1911) (Spring Green, Wisconsin) ; City Residential Land Development (unbuilt) (Frank Lloyd Wright, 1913) (Chicago, Illinois) ; Ocatilla Desert Camp (Frank Lloyd Wright, 1927) (Arizona) ; Rush City Reformed (unbuilt) (Richard Joseph Neutra, 1927) ; San Marcos In The Desert (unbuilt) (Frank Lloyd Wright, 1928-1929) (Chandler, Arizona) ; Malcolm Willey House (Frank Lloyd Wright, 1932-1934) (Minneapolis, Minnesota) ; Herbert Jacobs House I (Frank Lloyd Wright, 1936-1937) (Madison, Wisconsin) ; Fallingwater (Frank Lloyd Wright, 1936-1939) (Mill Run, Pennsylvania) ; Taliesin West (Frank Lloyd Wright, 1937) (Scottsdale, Arizona) ; Suntop Homes (The Ardmore Experiment) (Frank Lloyd Wright, 1938-1939) (Ardmore, Pennsylvania) ; Herbert Jacobs House II (Frank Lloyd Wright, 1938-1943) (Middleton, Wisconsin) ; Loren Pope House (Frank Lloyd Wright, 1939) (Falls Church, Virginia) ; Theodore Baird House (Frank Lloyd Wright, 1940) (Amherst, Massachusetts) ; Cloverleaf Quadruple Housing (Frank Lloyd Wright, 1942) (Pittsfield, Massachusetts) ; Carver Court (George Howe and Louis I. Kahn and Oscar Stonorov, 1942-1944) (Caln Township, Pennsylvania) ; Lowell Walter House (Frank Lloyd Wright, 1945) (Quasqueton, Iowa) ; Parkwyn Village (Frank Lloyd Wright, 1947) (Kalamazoo, Michigan) ; Pittsburgh Point Civic Center (unbuilt) (Frank Lloyd Wright, 1947-1948) (Pittsburgh, Pennsylvania) ; The Acres (Frank Lloyd Wright, 1947-1954) (Charleston Township, Michigan) ; Isadore J. Zimmerman house (Frank Lloyd Wright, 1950) (Manchester, New Hampshire) ; Robert Llewellyn Wright House (Frank Lloyd Wright, 1953) (Bethesda, Maryland) ; Price Tower (Frank Lloyd Wright, 1953-1956) (Bartlesville, Oklahoma) ; William Thaxton House (Frank Lloyd Wright, 1954) (Houston, Texas) ; Arthur Miller House (unbuilt) (Frank Lloyd Wright, 1956) (Roxbury, Connecticut) ; The Illinois (unbuilt) (Frank Lloyd Wright, 1956) (Chicago, Illinois) ; Housing for Negro Families for Jesse Fisher (unbuilt) (Frank Lloyd Wright, 1957) (Whiteville, North Carolina) ; David Wright House (Frank Lloyd Wright) (Phoenix, Arizona) ; Usonia Historic District (Frank Lloyd Wright) (Pleasantville, New York)Audio files are EID restricted. Individuals without an EID should send an email request to [email protected] Librarie

Building The Dream : A Social History Of Housing In America

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Introduction: Shifting Paradigms and Concerns

status: publishe