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X-Ray Magnetic Circular Dichroism Of Pulsed Laser Deposited Co2mnsn And Co2mnsb Thin Films Grown On Gaas (001), Moti R. Paudel, Christopher S. Wolfe, Naushad Ali, Shane Stadler, Joseph A. Christodoulides, David L. Ederer, Yinwan Li, Thomas A. Callcott, John W. Freeland May 2009

X-Ray Magnetic Circular Dichroism Of Pulsed Laser Deposited Co2mnsn And Co2mnsb Thin Films Grown On Gaas (001), Moti R. Paudel, Christopher S. Wolfe, Naushad Ali, Shane Stadler, Joseph A. Christodoulides, David L. Ederer, Yinwan Li, Thomas A. Callcott, John W. Freeland

Publications

We present the structural and element specific magnetic properties of Co2MnSn and Co2MnSb thin films grown on GaAs (100) substrates using pulsed laser deposition. X-ray magnetic circular dichroism (XMCD) spectra were measured for 400 A thick films at the L2,3 edges of Co and Mn. Element specific moments for Co and Mn in Co2MnSn were calculated from the x-ray absorption and XMCD spectra using the XMCD sum rules. The ratios of orbital to spin magnetic moments for Co and Mn were calculated for Co2MnSn and Co2MnSb.

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Spitzer Observations Of The Oldest White Dwarfs In The Solar Neighborhood, Mukremin Kilic, Ted Von Hippel, Et Al. May 2009

Spitzer Observations Of The Oldest White Dwarfs In The Solar Neighborhood, Mukremin Kilic, Ted Von Hippel, Et Al.

Publications

We present Spitzer 5-15 μm spectroscopy of one cool white dwarf and 3.6-8 μm photometry of 51 cool white dwarfs with T eff < 6000 K. The majority of our targets have accurate BVRIJHKphotometry and trigonometric parallax measurements available, which enables us to perform a detailed model atmosphere analysis using their optical, near- and mid-infrared photometry with state-of-the-art model atmospheres. We demonstrate that the optical and infrared spectral energy distributions of cool white dwarfs are well reproduced by our grid of models. Our best-fit models are consistent with the observations within 5% in all filters except the IRAC 8 μm band, which has the lowest signal-to-noise ratio photometry. Excluding …

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Memory Functioning In Developmental Dyslexia: An Analysis Using Two Clinical Memory Measures., Michelle Y. Kibby May 2009

Memory Functioning In Developmental Dyslexia: An Analysis Using Two Clinical Memory Measures., Michelle Y. Kibby

Publications

The goals of this project were threefold: to determine the nature of the memory deficit in children/adolescents with dyslexia, to utilize clinical memory measures in this endeavor, and to determine the extent to which semantic short-term memory (STM) is related to basic reading performance. Two studies were conducted using different samples, one incorporating the Wide Range Assessment of Memory and Learning and the other incorporating the California Verbal Learning Test-Children's Version. Results suggest that phonological STM is deficient in children with dyslexia, but semantic STM and visual-spatial STM are intact. Long-term memory (LTM) for both visual and verbal material also …

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The Very Short Supersoft X-Ray State Of The Classical Nova M31n 2007-11a, M. Henze, W. Pietsch, G. Sala, M. Della Valle, M. Hernanz, J. Greiner, V. Burwitz, M. J. Freyberg, F. Haberl, Dieter H. Hartmann, P Milne, G G. Williams May 2009

The Very Short Supersoft X-Ray State Of The Classical Nova M31n 2007-11a, M. Henze, W. Pietsch, G. Sala, M. Della Valle, M. Hernanz, J. Greiner, V. Burwitz, M. J. Freyberg, F. Haberl, Dieter H. Hartmann, P Milne, G G. Williams

Publications

Context. Short supersoft X-ray source (SSS) states (durations ≤100 days) of classical novae (CNe) indicate massive white dwarfs that are candidate progenitors of supernovae type Ia. Aims. We carry out a dedicated optical and X-ray monitoring program of CNe in the bulge of M 31. Methods. We discovered M31N 2007-11a and determined its optical and X-ray light curve. We used the robotic Super-LOTIS tele-scope to obtain the optical data and XMM-Newton and Chandra observations to discover an X-ray counterpart to that nova. Results. Nova M31N 2007-11a is a very fast CN, exhibiting a very short SSS state with an appearance …

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Warning! Engineers In Training: Introducing Middle School Students To Industrial Engineering, Its Usefulness, And Its Applications, M. Grubb, A. Berger, D. Browning, M. Mayorga, Laine Mears May 2009

Warning! Engineers In Training: Introducing Middle School Students To Industrial Engineering, Its Usefulness, And Its Applications, M. Grubb, A. Berger, D. Browning, M. Mayorga, Laine Mears

Publications

The McCants Middle School Pre-engineering class is designed to teach engineering skills to students with a predisposition for and interest in math and science. This team’s initiative is to use Industrial Engineering tools to enhance the existing pre-engineering course curriculum. The purpose of this study is to make middle school students better aware of an engineer’s thought process as it pertains to effectively planning and working on projects, and to measure the impact of our influence. Through this study, we want to improve the overall quality of the student’s projects and ultimately increase the retention and quantity of students interested …

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The Reestablishment Of American Ginseng (Panax Quinquefolius), Mary Snow, Richard Snow May 2009

The Reestablishment Of American Ginseng (Panax Quinquefolius), Mary Snow, Richard Snow

Publications

Conservation biology and restoration ecology are concerned not only with protecting fragile ecosystems but also with intervening in an attempt to repair what has been damaged largely through anthropogenic activities. As a result of high demand as a medicinal herb and the failure of harvesters to conserve, the federal government has placed American ginseng (Panax quinquefolius) on the list of plants that may be in danger of extinction. Ginseng favors a habitat ranging from 30 to 50 degrees north latitude and minimum cold cycles of 45 days with temperatures below 2 degrees Celsius. Other specific criteria include 20 inches of …

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Inverting Color–Magnitude Diagrams To Access Precise Star Cluster Parameters: A New White Dwarf Age For The Hyades, Steven Degennaro, Ted Von Hippel, Et Al. May 2009

Inverting Color–Magnitude Diagrams To Access Precise Star Cluster Parameters: A New White Dwarf Age For The Hyades, Steven Degennaro, Ted Von Hippel, Et Al.

Publications

We have extended our Bayesian modeling of stellar clusters—which uses main-sequence stellar evolution models, a mapping between initial masses and white dwarf (WD) masses, WD cooling models, and WD atmospheres—to include binary stars, field stars, and two additional main-sequence stellar evolution models. As a critical test of our Bayesian modeling technique, we apply it to Hyades UBV photometry, with membership priors based on proper motions and radial velocities, where available. Under the assumption of a particular set of WD cooling models and atmosphere models, we estimate the age of the Hyades based on cooling WDs to be 648 ± 45 …

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Uaa Student Showcase Journal: Recognizing Excellence (2009), N/A N/A Apr 2009

Uaa Student Showcase Journal: Recognizing Excellence (2009), N/A N/A

Publications

No abstract provided.

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A Bark Thickness Model For White Spruce In Alaska Northern Forests, Thomas Malone, Jingjing Liang Apr 2009

A Bark Thickness Model For White Spruce In Alaska Northern Forests, Thomas Malone, Jingjing Liang

Publications

Here we developed a simple linear model to estimate white spruce bark thickness in the northern forests of Alaska. Data were collected from six areas throughout interior and southcentral Alaska. Geographic variation of bark thickness was tested between the Alaska statewide model and for each geographic area. The results show that the Alaska statewide model is accurate, simple, and robust, and has no practical geographic variation over the six areas. The model provides accurate estimates of the bark thickness for white spruce trees in Alaska for a wide array of future studies, and it is in demand by landowners and …

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A Technology Survey Of Emergency Recovery And Flight Termination Systems For Uas, Richard Stansbury, Wesley Tanis, Timothy Wilson Apr 2009

A Technology Survey Of Emergency Recovery And Flight Termination Systems For Uas, Richard Stansbury, Wesley Tanis, Timothy Wilson

Publications

For safe flight in the National Airspace System (NAS), either under the current interim rules or under anticipated longer-term regulatory guidelines facilitating unmanned aircraft system (UAS) access to the NAS, the UAS must incorporate technologies and flight procedures to ensure that neither people nor property in the air, on the ground, or on or in the water are endangered by the failure of an onboard component, by inappropriate unmanned aircraft (UA) response to pilot commands, or by inadvertent entry by the UA into prohibited airspace. The aircraft must be equipped with emergency recovery (ER) procedures and technologies that ensure that …

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Magnetic And Electrical Properties Of Ni50mn35in15−Xsix Heusler Alloys, Arjun Kumar Pathak, Igor Dubenko, Shane Stadler, Naushad Ali Apr 2009

Magnetic And Electrical Properties Of Ni50mn35in15−Xsix Heusler Alloys, Arjun Kumar Pathak, Igor Dubenko, Shane Stadler, Naushad Ali

Publications

We have studied the magnetic and electrical properties of the polycrystalline ferromagnetic Ni50Mn35In15−xSix (1 ≤ x ≤ 5) Heusler alloys through magnetization, thermal expansion, and resistivity measurements. It was observed that an increase in Si concentration strongly affects the ground state of the martensitic phase and the magnetic properties of compounds. A magnetic phase diagram has been constructed for these alloys. It was found that both martensitic transition temperature (TM) and Curie temperature of austenitic phase (TC) decrease, while ferromagnetic ordering temperature of the martensitic phase …

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Optical Pulsars And Black Arrows: Discoveries As Occasioned Productions, Timothy Koschmann, Alan Zemel Apr 2009

Optical Pulsars And Black Arrows: Discoveries As Occasioned Productions, Timothy Koschmann, Alan Zemel

Publications

The current paper represents a methodological proposal. It seeks to address the question of how one might recognize a discovery as a discovery without knowing in advance what is available to be discovered. We propose a solution and demonstrate it using data from a study previously reported by Roschelle (1992). Roschelle investigated two students’ discovery of certain abstract features of Newtonian mechanics while working within a computer-based microworld, the Envisioning Machine. We employ an approach we term discovery-as-occasioned-production to re-examine his data. Such an approach proceeds stepwise from the identification of some matter discovered, working backwards to see just where …

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Library Leadership In Action, Eric C. Shoaf Apr 2009

Library Leadership In Action, Eric C. Shoaf

Publications

The article presents several answers to a question asking about examples of library leadership at various institutions which includes adapting to users, leading by example, and empowering staff members.

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Simulation And Behavior Of Corrosion Deteriorated Reinforced Concrete Members, M. A. Shayanfar, Amir Safiey Apr 2009

Simulation And Behavior Of Corrosion Deteriorated Reinforced Concrete Members, M. A. Shayanfar, Amir Safiey

Publications

Several reinforced concrete (RC) infrastructures are now crumbling from corrosion of steel bars in concrete. The paper presents the recent advancements in analytical simulation of corrosion aftereffects on behavior of RC members. The model juxtaposes the experimental findings with analytical relationships. The implementation of the model into a nonlinear finite element formulation as well as the experimental and analytical backgrounds are discussed. The abilities of the resulted program have been studied by modeling some experimental specimens showing a reasonable agreement between the analytical and experimental findings.

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Foiling The Black Knight, Kelly C. Smith Apr 2009

Foiling The Black Knight, Kelly C. Smith

Publications

Why is the academy in general, and philosophy in particular, not more involved in the fight against the creationist threat? And why, when a response is offered, is it so curiously ineffective? I argue, by using an analogy with the battle against the Black Knight from the movie Monty Python and the Holy Grail, that the difficulty lies largely in a failure to see the nature of the problem clearly. By modifying the analogy, it is possible to see both why large sections of the academy have remained unmoved and also why many of the reactions to the threat …

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The Platycerus (Coleoptera, Lucanidae) Of California, With The Recognition Of Platycerus Cribripennis Van Dyke As A Valid Species, Michael S. Caterino, M J. Paulson Apr 2009

The Platycerus (Coleoptera, Lucanidae) Of California, With The Recognition Of Platycerus Cribripennis Van Dyke As A Valid Species, Michael S. Caterino, M J. Paulson

Publications

Th e status of Platycerus cribripennis Van Dyke, generally treated as a synonym of P. marginalis Casey, has been unclear. Here we recognize and redescribe P. cribripennis, which is endemic to the coastal mountains of California, as a valid species due to its unique morphology. A key to the Platycerus of California is presented, and the distributions of the recognized species are discussed.

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"Growing Without Limitations:" Transformation Among Young Adult Camp Staff, Barry A. Garst, Nancy K. Franz, Sarah Baughman, Chris Smith, Brian Peters Apr 2009

"Growing Without Limitations:" Transformation Among Young Adult Camp Staff, Barry A. Garst, Nancy K. Franz, Sarah Baughman, Chris Smith, Brian Peters

Publications

A strong body of research has developed over the last decade regarding the developmental outcomes of camp experiences of children and adolescents. However, few formal studies have been conducted to determine how camp experiences lead to deep personal change in young adult staff. In this study, the authors used focus groups and an online survey to explore transformation among young adult camp staff. Specifically, they examined (a) how camp involvement promotes transformation in young adults, and (b) what conditions in the camp environment promote personal change. Staff reported that personal change at camp was related to the developmental outcomes they …

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Leading The Way, Eric C. Shoaf Apr 2009

Leading The Way, Eric C. Shoaf

Publications

An introduction to the journal is presented in which the editor discusses a round-table discussion led by Pixey Anne Mosley, a survey concerning the provision of library leadership, and an article about a homegrown leadership development program by Alex Merrill and Elizabeth Lindsay.

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The Relationship Between Cerebral Hemisphere Volume And Receptive Language Functioning In Dyslexia And Attention-Deficit Hyperactivity Disorder (Adhd)., Michelle Y. Kibby, Shital P. Pavawalla, Jill B. Fancher, Angela J. Naillon, George W. Hynd Apr 2009

The Relationship Between Cerebral Hemisphere Volume And Receptive Language Functioning In Dyslexia And Attention-Deficit Hyperactivity Disorder (Adhd)., Michelle Y. Kibby, Shital P. Pavawalla, Jill B. Fancher, Angela J. Naillon, George W. Hynd

Publications

Because poor comprehension has been associated with small cerebral volume and there is a high comorbidity between developmental dyslexia, attention-deficit hyperactivity disorder (ADHD), and specific language impairment, the goal of this study was to determine whether cerebral volume is reduced in dyslexia and attention-deficit hyperactivity disorder in general, as some suggest, or whether the reduction in volume corresponds to poor receptive language functioning, regardless of the diagnosis. Participants included 46 children with and without dyslexia and attention-deficit hyperactivity disorder, aged 8 to 12 years. Our results indicated that cerebral volume was comparable between those with and without dyslexia and attention-deficit …

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Bayesian Irt Models Incorporating General And Specific Abilities, Yanyan Sheng, Christopher K. Wikle Apr 2009

Bayesian Irt Models Incorporating General And Specific Abilities, Yanyan Sheng, Christopher K. Wikle

Publications

IRT-based models with a general ability and several specific ability dimensions are useful. Studies have looked at item response models where the general and specific ability dimensions form a hierarchical structure. It is also possible that the general and specific abilities directly underlie all test items. A multidimensional IRT model with such an additive structure is proposed under the Bayesian framework. Simulation studies were conducted to evaluate parameter recovery as well as model comparisons. A real data example is also provided. The results suggest that the proposed additive model offers a better way to represent the test situations not realized …

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Magnetic Anisotropy Of Co2mnsn1−Xsbx Thin Films Grown On Gaas (001), Moti R. Paudel, Christopher S. Wolfe, Heather M.A. Patton, Jeff Simonson, Igor Dubenko, Naushad Ali, Shane Stadler Apr 2009

Magnetic Anisotropy Of Co2mnsn1−Xsbx Thin Films Grown On Gaas (001), Moti R. Paudel, Christopher S. Wolfe, Heather M.A. Patton, Jeff Simonson, Igor Dubenko, Naushad Ali, Shane Stadler

Publications

Heusler alloy Co2MnSn1−xSbx (x = 0.0, 0.5, and 1.0) thin films were grown on GaAs (001) substrates using pulsed laser deposition techniques. Growth parameters have been determined that result in highly magnetically anisotropic, crystalline, and oriented (001) films. The angular dependences, relative to the GaAs (001) crystallographic directions, of the coercive field Hc(θ) and the remanence Mr(θ) were determined from angle dependent magneto-optic Kerr effect (MOKE) measurements. It was found that Hc(θ) revealed higher order symmetry contributions to the magnetic anisotropy …

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Identifying The Key Factors In The Effectiveness And Failure Of Virtual Teams, Matthew P. Earnhardt Apr 2009

Identifying The Key Factors In The Effectiveness And Failure Of Virtual Teams, Matthew P. Earnhardt

Publications

Virtual teams, “individuals collaborating in geographically dispersed work teams who may reside in different time zones and countries” (Horwitz, Bravington, & Silvis, 2006, p. 472), are continuing to increase in frequency in today’s global economy. These teams have become a vital option for organizations that need to work in multiple locales at once and draw on vast global expertise. In fact, virtual teams and e-collaboration is considered an alternative to previously traditional formats, because of the cost savings and lack of space limitations associated with operating via virtual means (Kock & Nosek, 2005).

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Images.Md - The Online Encyclopedia Of Medical Images, Christee King Apr 2009

Images.Md - The Online Encyclopedia Of Medical Images, Christee King

Publications

images.MD is a searchable collection of more than 70,000 medical images, charts, and tables from atlases published by the Current Medical Group LLC. Images may be saved and used for personal study or teaching.

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Grb 080913 At Redshift 6.7, J. Greiner, T. Krühler, J. P. U. Fynbo, A. Rossi, R. Schwarz, S. Klose, S. Savaglio, N. R. Tanvir, S. Mcbreen, T Totani, B B. Zhang, X F. Wu, D Watson, S D. Barthelmy, A P. Beardmore, P Ferrero, N Gehrels, D A. Kann, N Kawai, A Küpcü Yoldaş, P Mészáros, B Milvang-Jensen, S R. Oates, D Pierini, P Schady, K Toma, P M. Vreeswijk, A Yoldas, B Zhang, P Afonso, K Aoki, D N. Burrows, C Clemens, R Filgas, Z Haiman, Dieter H. Hartmann Mar 2009

Grb 080913 At Redshift 6.7, J. Greiner, T. Krühler, J. P. U. Fynbo, A. Rossi, R. Schwarz, S. Klose, S. Savaglio, N. R. Tanvir, S. Mcbreen, T Totani, B B. Zhang, X F. Wu, D Watson, S D. Barthelmy, A P. Beardmore, P Ferrero, N Gehrels, D A. Kann, N Kawai, A Küpcü Yoldaş, P Mészáros, B Milvang-Jensen, S R. Oates, D Pierini, P Schady, K Toma, P M. Vreeswijk, A Yoldas, B Zhang, P Afonso, K Aoki, D N. Burrows, C Clemens, R Filgas, Z Haiman, Dieter H. Hartmann

Publications

We report on the detection by Swift of GRB 080913, and subsequent optical/near-infrared follow-up observations by GROND, which led to the discovery of its optical/NIR afterglow and the recognition of its high-z nature via the detection of a spectral break between the i and z bands. Spectroscopy obtained at the ESO-VLT revealed a continuum extending down to λ = 9400 Å, and zero flux for 7500 Å<λ< 9400 Å, which we interpret as the onset of a Gunn–Peterson trough at z = 6.695± 0.025 (95.5% confidence level), making GRB 080913 the highest-redshift gamma-ray burst (GRB) to date, and more distant than the highest-redshift QSO. We note that many redshift indicators that are based on promptly available burst or afterglow properties have failed for GRB 080913. We report on our follow-up campaign and compare the properties of GRB 080913 with bursts at lower redshift. In particular, since the afterglow of this burst is fainter than typical for GRBs, we show that 2 m class telescopes can identify most high-redshift GRBs.

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University Of New Mexico Health Sciences Library And Informatics Center Biomedical Informatics Fellowship Curriculum Specification, Philip J. Kroth Mar 2009

University Of New Mexico Health Sciences Library And Informatics Center Biomedical Informatics Fellowship Curriculum Specification, Philip J. Kroth

Publications

This entry is composed of two files. The first file named UNM HSLIC BMI Fellowship Competencies 20090309_pjk.pdf' contains the competencies-based curriculum specification for the University of New Mexico Health Sciences Library and Informatics Center's Biomedical Informatics Training Program Fellowship. This fellowship consists of 2-3 years of training in biomedical informatics and includes a mentored research project. The goal of the fellowship is to produce an independently fundable junior investigator in biomedical informatics. The curriculum has been designed using well-written (and demonstrable and assessable) educational objectives in the form recommended by Robert Mager in his book 'Preparing instructional objectives', Belmont, CA.: …

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The Economic Situation, 2009 March, Bruce Yandle Mar 2009

The Economic Situation, 2009 March, Bruce Yandle

Publications

Quarterly report on the economic situation of the United States and South Carolina.

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Water Level Observations In Mangrove Swamps During Two Hurricanes In Florida, William Conner, Thomas W. Doyle, Terry J. Doyle, Christopher Swarzenski, Andrew S. From, Richard H. Day, Ken W. Krauss Mar 2009

Water Level Observations In Mangrove Swamps During Two Hurricanes In Florida, William Conner, Thomas W. Doyle, Terry J. Doyle, Christopher Swarzenski, Andrew S. From, Richard H. Day, Ken W. Krauss

Publications

Little is known about the effectiveness of mangroves in suppressing water level heights during landfall of tropical storms and hurricanes. Recent hurricane strikes along the Gulf Coast of the United States have impacted wetland integrity in some areas and hastened the need to understand how and to what degree coastal forested wetlands confer protection by reducing the height of peak water level. In recent years, U.S. Geological Survey Gulf Coast research projects in Florida have instrumented mangrove sites with continuous water level recorders. Our ad hoc network of water level recorders documented the rise, peak, and fall of water levels …

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Modeling Effects Of Human Single Nucleotide Polymorphisms On Protein-Protein Interactions, Shaolei Teng, Thomas Madej, Anna Panchenko, Emil Alexov Mar 2009

Modeling Effects Of Human Single Nucleotide Polymorphisms On Protein-Protein Interactions, Shaolei Teng, Thomas Madej, Anna Panchenko, Emil Alexov

Publications

A large set of three-dimensional structures of 264 protein-protein complexes with known nonsynonymous single nucleotide polymorphisms (nsSNPs) at the interface was built using homology-based methods. The nsSNPs were mapped on the proteins' structures and their effect on the binding energy was investigated with CHARMM force field and continuum electrostatic calculations. Two sets of nsSNPs were studied: disease annotated Online Mendelian Inheritance in Man (OMIM) and nonannotated (non-OMIM). It was demonstrated that OMIM nsSNPs tend to destabilize the electrostatic component of the binding energy, in contrast with the effect of non-OMIM nsSNPs. In addition, it was shown that the change of …

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Declining Recruitment And Growth Of Shovelnose Sturgeon In The Middle Mississippi River: Implications For Conservation, Sara J. Tripp, Robert E. Colombo, James E. Garvey Mar 2009

Declining Recruitment And Growth Of Shovelnose Sturgeon In The Middle Mississippi River: Implications For Conservation, Sara J. Tripp, Robert E. Colombo, James E. Garvey

Publications

To determine how populations of shovelnose sturgeon Scaphirhynchus platorynchus are changing and may respond to poor environmental conditions, current commercial harvest of black-egg (sexually mature) females, and incidental mortality of males, we require annual information about sex-specific age structure as it relates to the recruitment of new cohorts. We sampled shovelnose sturgeon by use of gill nets (5-cm bar mesh) monthly during 2002-2006 in the Middle Mississippi River between Cairo, Illinois, and St. Louis, Missouri. We compared patterns of size and age structure over time and projected age structure and population size into the future. Sex ratio in 2005-2006 was …

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The Dust Cloud Around The White Dwarf G 29-38. Ii. Spectrum From 5 To 40 Μm And Mid-Infrared Photometric Variability, William T. Reach, Ted Von Hippel, Et Al. Mar 2009

The Dust Cloud Around The White Dwarf G 29-38. Ii. Spectrum From 5 To 40 Μm And Mid-Infrared Photometric Variability, William T. Reach, Ted Von Hippel, Et Al.

Publications

We model the mineralogy and distribution of dust around the white dwarf G29-39 using the infrared spectrum from 1 to 35 μm. The spectral model for G29-38 dust combines a wide range of materials based on spectral studies of comets and debris disks. In order of their contribution to the mid-infrared emission, the most abundant minerals around G29-38 are amorphous carbon (λ < 8 μm), amorphous and crystalline silicates (5-40 μm), water ice (10-15 and 23-35 μm), and metal sulfides (18-28 μm). The amorphous C can be equivalently replaced by other materials (like metallic Fe) with featureless infrared spectra. The best-fitting crystalline silicate is Fe-rich pyroxene. In order to absorb enough starlight to power the observed emission, the disk must either be much thinner than the stellar radius (so that it can be heated from above and below) or it must have an opening angle wider than 2°. A "moderately optically thick" torus model fits well if the dust extends inward to 50 times the white dwarf radius, all grains hotter than 1100 K are vaporized, the optical depth from the star through the disk is τ∥ = 5, and the radial density profile ∝r –2.7; the total mass of this model disk is 2 × 1019 g. A physically thin (less than the white dwarf radius) and optically thick disk can contribute to the near-infrared continuum only; such a disk cannot …

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