273 research outputs found
DREIDING: A generic force field for molecular simulations
We report the parameters for a new generic force field, DREIDING, that we find useful for predicting structures and dynamics of organic, biological, and main-group inorganic molecules. The philosophy in DREIDING is to use general force constants and geometry parameters based on simple hybridization considerations rather than individual force constants and geometric parameters that depend on the particular combination of atoms involved in the bond, angle, or torsion terms. Thus all bond distances are derived from atomic radii, and there is only one force constant each for bonds, angles, and inversions and only six different values for torsional barriers. Parameters are defined for all possible combinations of atoms and new atoms can be added to the force field rather simply. This paper reports the parameters for the "nonmetallic" main-group elements (B, C, N, 0, F columns for the C, Si, Ge, and Sn rows) plus H and a few metals (Na, Ca, Zn, Fe). The accuracy of the DREIDING force field is tested by comparing with (i) 76 accurately determined crystal structures of organic compounds involving H, C, N, 0, F, P, S, CI, and Br, (ii) rotational barriers of a number of molecules, and (iii) relative conformational energies and barriers of a number of molecules. We find excellent results for these systems
Assessing âDiscover Mojaveâ, Year Two: Final Report
Discover Mojave Outdoor World is a hands-on outdoor recreation program for urban, economically disadvantaged youth. In Year One of the program, knowledge, attitude, and performance assessments were developed to document the effectiveness of program events over the duration of the program. Year One findings revealed that knowledge, attitudes, and performance increased substantially as a result of participating in the outdoor recreation events. The assessment plan was modified in Year Two by creating assessments for teachers and parents, as well as a developing a structured interview protocol. Changes were made to existing assessments and two new assessment tools were implemented. Findings from Year Twoâs assessment plan again demonstrated the effectiveness of Discover Mojave Outdoor World in that participantsâ knowledge, attitudes, and performance increased over the course of program events. Additionally, results demonstrated that teachers and parents had very favorable attitudes towards the program
Assessment of Forever Earth Curriculum 2009-2010: Final Report
Forever Earth is a floating environmental laboratory and learning center at Lake Mead National Recreation Area that provides hands-on science experiences for students in the Clark County School District. The Forever Earth program was brought about through the efforts of numerous partners including Forever Resorts, a division of Forever Learning LLC, the National Park Service, Lake Mead National Recreation Area; Outside Las Vegas Foundation; and UNLVâs Public Lands Institute. In 2005, a formal written agreement was reached between Fun Country Marine Industries and UNLVâs Public Lands Institute to operate and manage the Forever Earth houseboat for the purpose of enhancing outdoor environmental education efforts in Southern Nevada. During the first year of the assessment program, knowledge, attitude, and performance assessments were developed to document the effectiveness of program events over the duration of the program. The findings from the first three years of assessment revealed that studentsâ knowledge and attitudes increased substantially as a result of participating in the Forever Earth field trips. Results also demonstrated that teachersâ perceptions of the curriculum were very favorable. In this final year of assessment (2009/2010), students again completed knowledge, attitude, and performance assessment and results indicated that studentsâ knowledge, attitudes, and skills increased substantially as a result of participating in the Forever Earth field trips
Assessment of Forever Earth Curriculum 2008-2009: Final Report
Forever Earth is a floating environmental laboratory and learning center at Lake Mead National Recreation Area that provides hands-on science experiences for students in the Clark County School District. The Forever Earth program was brought about through the efforts of numerous partners including Forever Resorts, a division of Forever Learning LLC, the National Park Service, Lake Mead National Recreation Area; Outside Las Vegas Foundation; and UNLVâs Public Lands Institute. In 2005, a formal written agreement was reached between Fun Country Marine Industries and UNLVâs Public Lands Institute to operate and manage the Forever Earth houseboat for the purpose of enhancing outdoor environmental education efforts in Southern Nevada. During the first year of the assessment program, knowledge, attitude, and performance assessments were developed to document the effectiveness of program events over the duration of the program. The findings from the first two years of assessment revealed that studentsâ knowledge and attitudes increased substantially as a result of participating in the Forever Earth field trips. Results also demonstrated that teachersâ perceptions of the curriculum were very favorable. In 2008-2009, the third year of assessing the program, students again completed knowledge, attitude, and performance assessment and results indicated that studentsâ knowledge, attitudes, and skills increased substantially as a result of participating in the Forever Earth field trips. Teachersâ perceptions of the Forever Earth curriculum continued to be positive
Assessing âDiscover Mojaveâ Instrument Development and Analysis: Final Report
We developed curriculum and a comprehensive assessment plan to determine whether hands-on outdoor recreation events promote knowledge, attitudes, and performance among at-risk urban children. Knowledge, attitude, and performance assessments were developed, refined and conducted through various stages based on cultural and language barriers as well a variety of age groups participating within the events. Findings revealed that knowledge, attitudes, and performance increased substantially as a result of participating in the outdoor recreation events. We conclude that the implementation and assessment of the program is strong. We also make several recommendations for future programs
Assessment of Forever Earth Curriculum 2006/2007: Final Report
Forever Earth is a floating environmental laboratory and learning center at Lake Mead National Recreation Area that provides hands-on science experiences for students in the Clark County School District. The Forever Earth program was brought about through the efforts of numerous partners including Forever Resorts, a division of Forever Learning, LLD: the National Park Service, Lake Mead National Recreation Area; Outside Las Vegas Foundation; and UNLVâs Public Lands Institute. In 2005, a formal written agreement was reached between Fun Country Marine Industries and UNLVâs Public Lands Institute to operate and manage the Forever Earth houseboat for the purpose of enhancing outdoor environmental education efforts in Southern Nevada. In Year One of the program, knowledge, attitude, and performance assessments were developed to document the effectiveness of program events over the duration of the program. Year One findings revealed that studentsâ knowledge and attitudes increased substantially as a result of participating in the Forever Earth field trips. Results also demonstrated that teachersâ perceptions of the curriculum were very favorable
Cow-Calf Producersâ Willingness to Pay for Bulls Resistant to Horn Flies (Diptera: Muscidae)
Horn flies (Haematobia irritans (L.)) have long posed animal health and welfare concerns. Economic losses to the cattle and dairy industries from their blood-feeding behavior include decreased weight gain, loss in milk productivity, and transmission of bacteria causing mastitis in cattle. Horn fly management strategies are labor intensive and can become ineffective due to the horn flyâs ability to develop insecticide resistance. Research indicates that for some cattle herds, genetically similar animals consistently have fewer flies suggesting those animals are horn fly resistant (HFR) and that the trait is heritable; however, it is currently unknown if cattle producers value this trait. Tennessee and Texas cow-calf producers were surveyed to estimate their willingness to pay for HFR bulls and to identify the factors affecting their decision to adopt a HFR bull in their herds. Results indicate that Tennessee and Texas cow-calf producers were willing to pay a premium of 51% and 59% above the base price, respectively, for a HFR bull with the intent to control horn flies within their herd. Producer perceptions of horn fly intensities and the HFR trait, along with their pest management practices, were factors that affected Tennessee and Texas producer willingness to adopt a HFR bull. In Texas, demographics of the producers and their farms also had a role. Knowing producers are willing to pay a premium for the HFR bull indicates that producers value the HFR trait and warrants additional research on the development, implementation, and assessment of the trait
Assessment: How Hard Can It Be?
Demonstrate how assessment of a curriculum-based education program can work. Share results of the Forever Earth program assessment Stimulate thought and discussion of how to implement assessment strategies for your program
Particulate methane monooxygenase contains only mononuclear copper centers
Bacteria that oxidize methane to methanol are central to mitigating emissions of methane, a potent greenhouse gas. The nature of the copper active site in the primary metabolic enzyme of these bacteria, particulate methane monooxygenase (pMMO), has been controversial owing to seemingly contradictory biochemical, spectroscopic, and crystallographic results. We present biochemical and electron paramagnetic resonance spectroscopic characterization most consistent with two monocopper sites within pMMO: one in the soluble PmoB subunit at the previously assigned active site (CuB) and one ~2 nanometers away in the membrane-bound PmoC subunit (CuC). On the basis of these results, we propose that a monocopper site is able to catalyze methane oxidation in pMMO
Heideggerâs Underdeveloped Conception of the Undistinguishedness (Indifferenz) of Everyday Human Existence
This chapter provides an interpretation of the early Heideggerâs underdeveloped conception of the undistinguishedness of everyday human existence in Being and Time. After explaining why certain translation choices of some key terms in this text are interpretively and philosophically important, I first provide a concise argument for why the social constitution interpretation of the relation between ownedness and unownedness makes better overall sense of Heideggerâs ambivalent attitude toward the social constitution of the human being than the standard existentialist interpretation of this relation. I then proceed to the heart of this chapter, which develops his inchoate conception of the undistinguishedness of everydayness by arguing that it specifies the third distinctive mode of concrete human existence in addition to ownedness and unownedness. Accordingly, I show how unownedness is actually a generic phenomenon with two distinct species, namely, undistinguishedness and disownedness, which are at once closely related to, but also differ in significant respects from, each other. Consequently, instead of taking for granted a one-dimensional and mutually exclusive opposition between âauthenticityâ and âinauthenticityâ, I argue that we should adopt a two-dimensional and more nuanced understanding of the relations among undistinguishedness, disownedness, and ownedness that intersects with Heideggerâs underappreciated distinction between genuineness and ungenuineness. After raising and replying to some objections to this interpretation of undistinguishedness, I conclude this chapter by briefly sketching three of its philosophical consequences and pointing out its potential as an important resource for contemporary social theories
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