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2010-2019
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UNT Scholarly Works
- The 2011 Beta Eta Spring Banquet. Celebration of Rediscovery of the Elements
- Article describing an Eta Beta celebration of the completion of James and Virginia Marshall's "Rediscovery of the Elements." Photographs from the event are included. Three separate articles appear on the right side of the page. digital.library.unt.edu/ark:/67531/metadc111260/
- The 2012 Republican Primaries
- This presentation is part of the faculty lecture series UNT Speaks Out on the 2012 Presidential Primaries. In this presentation, the author gives the audience an overview of the structure of the primaries, and provides a recap of past primaries. The author also speaks about the money, momentum, and media attention in the primaries. digital.library.unt.edu/ark:/67531/metadc83792/
- Abraham model correlations for solute partitioning into o-xylene, m-xylene and p-xylene from both water and the gas phase
- This article discusses Abraham model correlations for solute partitioning into o-xylene, m-xylene and p-xylene from both water and the gas phase. Abstract: Experimental data have been compiled from the publisher literature on the partition coefficients of solutes and vapors into o-xylene, m-xylene and p-xylene at 298 K. The logarithms of the water-to-xylene partition coefficients, log P, and gas-to-xylene partition coefficients, log K, were correlated with the Abraham solvation parameter model. The derived mathematical expressions described the observed log P and log K data for the three xylene isomers to within average deviations of 0.14 log units or less. digital.library.unt.edu/ark:/67531/metadc155635/
- Abraham Model Correlations for Transfer of Neutral Molecules and Ions to Sulfolane
- This article discusses Abraham model correlations for the transfer of neutral molecules and ions to sulfolane. Data have been compiled from the published literature on the partition coefficients of solutes and vapors into anhydrous sulfolane. The logarithms of the water-to-sulfolane partition coefficients, log P, and gas-to-sulfolane partition coefficients, log K, were correlated with the Abraham solvation parameter model. The derived correlations described the observed log P and log K values for solutes dissolved in sulfolane to within average standard deviations of 0.14 log units or less. The log P correlation was extended to include the partition of ions by inclusion of a cation-solvent and an anion-solvent term. digital.library.unt.edu/ark:/67531/metadc157293/
- Accountable Science: The COMPETES Act Needs to Demonstrate an Accountability Attitude
- This article discusses the U.S. National Science Foundation's (NSF) Broader Impacts Merit Review Criterion in relation to the America COMPETES Reauthorization Act of 2010. digital.library.unt.edu/ark:/67531/metadc86163/
- Activation of water on the TiO2 (110) surface: The case of Ti adatoms
- This article discusses the activation of water on the TiO2 (110) surface. Abstract: Using first-principles calculations the authors have studied the reactions of water over Ti adatoms on the (110) surface of rutile TiO2. The authors' results provide fundamental insights into the microscopic mechanisms that drive this reaction at the atomic level and assess the possibility of using this system to activate the water dissociation reaction. In particular, the authors show that a single water molecule dissociates exothermically with a small energy barrier of 0.17 eV. After dissociation, both H⁺ and OH⁻ ions bind strongly to the Ti adatom, which serves as an effective reactive center on the TiO2 surface. Finally, clustering of Ti adatoms does not improve the redox activity of the system and results in a slightly higher energy barrier for water dissociation. digital.library.unt.edu/ark:/67531/metadc132989/
- Analytical solutions for a two-level system driven by a class of chirped pulses
- In this article, the authors present analytical solutions for the problem of a two-level atom driven by a class of chirped pulses. The solutions are given in terms of Heun functions. By use of the appropriate chirping parameters, an enhancement of four orders of magnitude in the population transfer is obtained. digital.library.unt.edu/ark:/67531/metadc103257/
- Analyzing How Business Students Engage in Learning in an Introductory Data Analysis Course
- This poster discusses an analysis of how business students engage in learning in an introductory data analysis course. A variety of pedagogical activities are used in this introductory data analysis course for business students. In fall of 2012, students were able to score points on each of the following activities: experiential group projects, clicker questions, learning modules, online post chapter quizzes, in class exams, and extra credit questions. An analysis was performed to determine how these activities relate to each other and to improvement in student grades. digital.library.unt.edu/ark:/67531/metadc157295/
- Beyond the Death of Linear Response: 1/f Optimal Information Transport
- This article discusses linear response and 1/f optimal information transport. Article: Nonergodic renewal processes have recently been shown by several authors to be insensitive to periodic perturbations, thereby apparently sanctioning the death of linear response, a building block of nonequilibrium statistical physics. The authors show that it is possible to go beyond the "death of linear response" and establish a permanent correlation between an external stimulus and the response of a complex network generating nonergodic renewal processes, by taking as stimulus a similar nonergodic process. The ideal condition of 1/f noise corresponds to a singularity that is expected to be relevant in several experimental conditions. digital.library.unt.edu/ark:/67531/metadc40407/
- Bieberians at the Gate?
- In this article, the authors discuss the idea that non-philosophers should judge philosophers. As universities face growing demands for academic accountability, philosophers ought to take the lead in exploring what accountability means. Otherwise we may be stuck with Dickens's Mr. Gradgrind. ("Now, what I want is Facts. Teach these boys and girls nothing but Facts. Facts along are wanted in life.") But a philosophical account of accountability will also require redefining the boundaries of what counts as philosophy. digital.library.unt.edu/ark:/67531/metadc130189/
- Biocultural conservation in Cape Horn: the Magellanic woodpecker as a charismatic species
- This book chapter discusses a research project to promote biocultural conservation in Cape Horn, Chile. At the southernmost tip of the Americas, the Cape Horn Biosphere Reserve (CHBR) encompasses one of the world's most pristine remaining wilderness areas and is home to the indigenous Yaghan (or Yamana) community, which featured prominently in Charles Darwin's 'Voyage of the Beagle'. Its remoteness and uniqueness, however, are threatened by the introduction of exotic species such as the North American beaver and American mink, increasing development pressures from new connectivity, resource exploitation, and the development of tourism. To implement the biosphere reserve and conserve its natural and cultural richness requires the active participation of the community, as well as linkages and integration between various disciplines and institutions. In an effort to achieve the goal of transdisciplinary integration, the authors used the strategy of identifying a charismatic species, since doing so serves to motivate people towards biodiversity conservation, to communicate ecological concepts, and to integrate both the ecological and social dimensions of sustainability. This study was developed together with the population of Puerto Williams, a town with 2200 inhabitants located on Navarino Island, and the largest human settlement within the CHBR. digital.library.unt.edu/ark:/67531/metadc97940/
- Biocultural Ethics: Recovering the Vital Links between the Inhabitants, Their Habits, and Habitats
- This article discusses biocultural ethics. Abstract: Biocultural homogenization involves three major drivers: (a) the physical barrier to everyday contact with biodiversity derived from the rapid growth of urban population, (b) the conceptual barrier derived from the omission in formal and non-formal education of native languages that contain a broad spectrum of traditional ecological knowledge and values, and (c) political barriers associated with the elimination or reduction of the teaching of ethics under the prevailing neoliberal economy governance since the 1960s. Biocultural ethics aims at overcoming these barriers by recovering the vital links between biological and cultural diversity, between the habits and the habitats of the inhabitants. These links are acknowledged by early Western philosophy. Amerindian traditional ecological knowledge, and contemporary ecological and evolutionary sciences, but have been lost in prevailing modern ethics. There is an overlooked diversity of forms of knowing and inhabiting regional ecosystems, each of them having diverse environmental and social consequences. A better understanding of the regionally diverse mosaics of ecosystems, languages, and cultures facilitates the distinction of specific causes and responsible agents of environmental problems, and the disclosure of sustainable practices, forms of ecological knowledge and values that offer already existing options to solve socio-ecological problems. digital.library.unt.edu/ark:/67531/metadc130202/
- The Biological and Toxicological Activity of Gases and Vapors
- This article discusses the biological and toxicological activity of gases and vapors. Abstract: A large amount of data on the biological and toxicological activity of gases and vapors has been collected from the literature. Processes include sensory irritation thresholds, the Alarie mouse test, inhalation anasthesia, etc. It is shown that a single equation using only five descriptors (properties of the gases and vapors) plus a set of indicator variables for the given processes can correlate 643 biological and non-lethal toxicological activities of 'non-reactive' compounds with a standard deviation of 0.36 log unit. The equation is scaled to sensory irritation thresholds obtained by the procedure of Cometto-Muñiz, and Cain, and provides a general equation for the prediction of sensory irritation thresholds in man. It is suggested that differences in biological/toxicological activity arise primarily from transport from the gas phase to a receptor phase or area, except for odor detection thresholds where interaction with a receptor(s) is important. digital.library.unt.edu/ark:/67531/metadc152441/
- Broader Impacts 2.0: Seeing- and Seizing- the Opportunity
- This article offers viewpoints on Broader Impacts 2.0. The authors point out that the National Science Board (NSB) has presented us with merit review criteria that challenge us to undertake research that marries scientific merit and broader impacts in a way that benefits the research community, our funding sources, and our society. digital.library.unt.edu/ark:/67531/metadc155643/
- Building a Chilean Network for Long-Term Socio-Ecological Research: Advances, perspectives and relevance
- This article discusses building a Chilean network for long-term socio-ecological research. Abstract: Since their formal inception in 1980, long-term ecological research (LTER) programs have served as a successful organizing framework to create research agendas and funding mechanisms that allow scientists to address meaningful ecological phenomena at the scales they occur. In its 30 years of existence, LTER has expanded its geographic range (currently the International LTER network has more than 40 country members with sites on every continent) and disciplinary foci (principally encompassing the natural and social sciences and leading some to call for a name change to long-term socio-ecological research efforts exist in both Chile and Argentina, and in 2008, the Institute of Ecology and Biodiversity launched Chile's first concerted effort to link three existing sites (Fray Jorge Forest National Park -33° S, Senda Darwin Biological Station - 43° S, and Omora Ethnobotanical Park - 55° S). Here, the authors present a special feature of the Revista Chilena de Historia Natural, dedicated to LTSER, with the aim of 1) providing a synthesis of some of the most emblematic cases of long-term socio-ecological research in Chile; 2) demonstrating the value of these efforts for the integration of research, education and social outcomes, such as decision making; and 3) offering the perspective of a broad array of participants involved in these initiatives, including graduate students with associated programs from Ibero-America and North America and North America. It is the authors' hope that these compiled works will contribute to the consolidation of the LTSER approach in southern South America both within the academic community and also to better link academia and society. digital.library.unt.edu/ark:/67531/metadc97937/
- C-H Functionalization Reactivity of a Nickel-Imide
- This article discusses C-H functionalization reactivity of a Nickel-Imide. Abstract: We report report bifunctional reactivity of the β-diketiminato Ni(III)-imide [Me₃NN]Ni=NAd (1), which undergoes H-atom abstraction (HAA) reactions with benzylic substrates R-H (indane, ethylbenzene, toluene). Nickel-imide 1 competes with the nickel-amide HAA product [Me₃NN]Ni-NHAd (2) for the resulting hydrocarbyl radical R• to give the nickel-amide [Me₃NN]Ni-N(CHMePh)Ad (3) (R-H = ethylbenzene) or aminoalkyl tautomer [Me₃NN]Ni(ɳ²-CH(Ph)NHAd) (4) (R-H = toluene). A significant amount of functionalized amine R-NHAd is observed in the reaction of 1 with indane along with the dinickel imide {[Me₃NN]Ni}₂(μ-NAd) (5). Kinetic and DFT analyses point to rate-limiting HAA from R-H by 1 to give R•, which may add to either imide 1 or amide 2, each featuring significant N-based radical character. Thus, these studies illustrate a fundamental competition possible in C-H amination systems that proceed via a HAA/radical rebound mechanism. digital.library.unt.edu/ark:/67531/metadc107790/
- Calculations of the Relative Energies of the 2B1g and 2A2u States of Cyclobutanetetraone Radical Cation and Radical Anion Provide Further Evidence of a 3B2u Ground State for the Neutral Molecule: A Proposed Experimental Test of the Prediction of a Triplet Ground State for (CO)4
- This article discusses ground states. Abstract: B3LYP, CCSD(T), and CASPT2 calculations with the 6-311+G(2df) basis set have been performed on the radical anion and radical cation of cyclobutanetetraone (1). The very similar energies computed for the 2B1g and 2A2u states of both 1·+ and 1·- indicate that the singly occupied b1g and a2u MOs in these two states of the radical cation and anion have nearly the same energies, thus supporting the previously made prediction that neutral 1 has a 3B2u ground state. Reaction of squaric acid with O.(-), followed by negative ion photoelectron spectroscopy (NIPES) on the 1.(-) thus formed, is proposed as an experimental test of the startling prediction that tetraketone (1), a molecule that would be expected to be a closed-shell singlet, actually has a triplet ground state. digital.library.unt.edu/ark:/67531/metadc71812/
- Calculations Predict That Carbon Tunneling Allows the Degenerate Cope Rearrangement of Semibullvalene to Occur Rapidly at Cryogenic Temperatures
- This article discusses carbon tunneling. Abstract: Calculations on the role of tunneling in the degenerate Cope rearrangements of semibullvalene (1) and barbaralane (3) predict that, at temperatures below 40 K, tunneling from the lowest vibrational level should make the temperature-independent rate constants k = 1.43 x 10(-3) s(-1) and k = 7.28 x 10(-9) s(-1), respectively. An experiment, using semibullvalene-2(4)-d1, is proposed to test the prediction of rapid tunneling by 1 at cryogenic temperatures. digital.library.unt.edu/ark:/67531/metadc71814/
- Carbon-Oxygen Bond Formation via Organometallic Baeyer-Villiger Transformations: A Computational Study on the Impact of Metal Identity
- This article discusses a computational study on the impact of metal identity. Abstract: Metal-mediated formation of C-O bonds is an important transformation that can occur by a variety of mechanisms. Recent studies suggest that oxygen-atom insertion into metal-hydrocarbyl bonds in a reaction that resembles the Baeyer-Villiger transformation is a viable process. In an effort to identify promising new systems, this study is designed to assess the impact of metal identity on such O-atom insertions for the reaction [(bpy)ₓM(Me)(OOH)]ⁿ → [(bpy)ₓM(OMe)(OH)]ⁿ (x = 1 or 2; bpy = 2,2'-bipyridyl; n is varied to maintain the d-electron count at d⁶ or d⁸). Six d⁸-square-planar complexes (M = Ptᴵᴵ, Pdᴵᴵ, Niᴵᴵ, Irᴵ, Rhᴵ, and Coᴵ) and eight d⁶-octahedral systems (M = Irᴵᴵᴵ, Rhᴵᴵᴵ, Coᴵᴵᴵ, Feᴵᴵ, Ruᴵᴵ, Osᴵᴵ, Mnᴵ, and Tcᴵ) are studied. Using density functional theory calculations, the structures and energies of ground-state and transition-state species are elucidated. This study shows clear trends in calculated ∆G‡'s for the O-atom insertions. The organometallic Baeyer-Villiger insertions are favored by lower coordination numbers (x = 1 versus x = 2), earlier transition metals, and first-row (3d) transition metals. digital.library.unt.edu/ark:/67531/metadc107789/
- Cardiac and metabolic physiology of early larval zebrafish (Danio rerio) reflects parental swimming stamina
- This article discusses cardiac and metabolic physiology of early larval zebrafish (Danio rerio) reflecting parental swimming stamina. Abstract: Swimming stamina in adult fish is heritable, it is unknown if inherited traits that support enhanced swimming stamina in offspring appear only in juveniles and/or adults, or if these traits actually appear earlier in the morphologically quite different larvae. To answer this question, mature adult zebrafish (Danio rerio) were subjected to a swimming performance test that allowed separation into low swimming stamina or high swimming stamina groups. Adults were then bred within their own performance groups. Larval offspring from each of the two groups, designated high (L(HSD)) and low stamina-derived larvae (L(LSD)), were then reared at 27°C in aerated water (21% O(2)). Routine (f(H),r) and active (f(H),a) heart rate, and routine [Formula: see text] and active [Formula: see text] mass-specific oxygen consumption were recorded from 5 days post fertilization (dpf) through 21 dpf, and gross cost of transport and factorial aerobic metabolic scope were derived from [Formula: see text] measurements. Heart rate generally ranged between 150 and 225 bpm in both L(HSD) and L(LSD) populations. However, significant (P<0.05) differences existed between the L(LSD) and L(HSD) populations at 5 and 14 dpf in f(H),r and at days 10 and 15 dpf in f(H),a. [Formula: see text] was 0.04-0.32 μmol mg(-1)h(01), while [Formula: see text] was 0.2-1.2 μmol mg(-1)h(-1). Significant (P<0.05) differences between the L(LSD) and L(HSD) populations in [Formula: see text] occurred at 7, 10, and 21 dpf and in [Formula: see text] at 7 dpf. Gross cost of transport was ~6-10 μmol O(2)-μg(-1)m(-1) at 5 dpf, peaking at 14-19 μmol O(2) μg(-1)m(-1) at 7-10 dpf, before falling again to 5-6 μmol O(2) μg(-1)m(-1) at 21 dpf, with gross cost of transport significantly higher in the L(LSD) population at 7 dpf. Collectively, these data indicate that inherited physiological differences known to contribute to enhanced stamina in adult parents also appear in their larval offspring well before attainment of juvenile or adult features. digital.library.unt.edu/ark:/67531/metadc115198/
- Caring for Yourself as a Caregiver
- This presentation is part of the faculty lecture series UNT Speaks Out on Alzheimer's Disease and Dementia. In this presentation, Bert Hayslip, Regents Professor in the Department of Psychology, will discuss caregiving for Alzheimer's and dementia patients. digital.library.unt.edu/ark:/67531/metadc146581/
- Carrier-Envelope Phase Effect on Atomic Excitation by Few-Cycle rf Pulses
- This article discusses carrier-envelope phase effect on atomic excitation by few-cycle rf pulses. Abstract: We present an experimental and theoretical study of the carrier-envelope phase effects on population transfer between two bound atomic states interacting with intense ultrashort pulses. Radio frequency pulses are used to transfer population among the ground state hyperfine levels in rubidium atoms. These pulses are only a few cycles in duration and have Rabi frequencies of the order of the carrier frequency. The phase difference between the carrier and the envelope of the pulses has a significant effect on the excitation of atomic coherence and population transfer. The authors provide a theoretical description of this phenomenon using density matrix equations. The authors discuss the implications and possible applications of their results. digital.library.unt.edu/ark:/67531/metadc103274/
- Cation-specific and anion-specific Abraham model correlations for solute transfer into ionic liquid solvents
- This article discusses cation-specific and anion-specific Abraham model correlations for solute transfer into ionic liquid solvents. Abstract: Data have been assembled from the published literature on the infinite dilution activity coefficients and gas solubilities of solutes dissolved in ionic liquid (IL) solvents. In total data for more than 1790 solute-IL pairs were compiled. The published experimental data were converted to gas-to-IL and water-to-IL partition coefficients, and correlated with the ion-specific equation coefficient version of the Abraham general solvation model. Ion-specific equation coefficients describe the experimental gas-to-IL and water-to-IL partition coefficient data to within 0.114 and 0.139 log units, respectively. Reported for the first time are equation coefficients for diethylphosphate, tris(pentafluoroethyl)trifluorophosphate and tetracyanoborate anions. digital.library.unt.edu/ark:/67531/metadc152450/
- Characteristic Male Urine Microbiomes Associate with Asymptomatic Sexually Transmitted Infection
- This article discusses characteristic male urine microbiomes. Abstract: Background: The microbiome of the male urogenital tract is poorly described but it has been suggested that bacterial colonization of the male urethra might impact risk of sexually transmitted infection (STI). Previous cultivation-dependent studies showed that a variety of non-pathogenic bacteria colonize the urethra but did not thoroughly characterize these microbiomes or establish links between the compositions of urethral microbiomes and STI. Methodology/Findings: Here, the authors used 165 rRNA PCR and sequencing to identify bacteria in urine specimens collected from men who lacked symptoms of urethral inflammation but who differed in status for STI. All of the urine samples contained multiple bacteria genera and many contained taxa that colonize the human vagina. Uncultivated bacteria associated with female genital tract pathology were abundant in specimens from men who had STI. Conclusions: Urine microbiomes from men with STI were dominated by fastidious, anaerobic and uncultivated bacteria. The same taxa were rare in STI negative individuals. The authors' findings suggest that the composition of male urine microbiomes is related to STI. digital.library.unt.edu/ark:/67531/metadc78333/
- Charge transfer equilibria in ambient-exposed epitaxial graphene on (0001) 6 H-SiC
- This article discusses charge transfer equilibria in ambient-exposed epitaxial graphene on (0001) 6 H-SiC. Abstract: The transport properties of electronic materials have been long interpreted independently from both the underlying bulk-like behavior of the substrate or the influence of ambient gases. This is no longer the case for ultra-thin graphene whose properties are dominated by the interfaces between the active material and its surroundings. Here, the authors show that the graphene interactions with its environments are critical for the electrostatic and electrochemical equilibrium of the active device layers and their transport properties. Based on the prototypical case of epitaxial graphene on (0001) 6 H-SiC and using a combination of 'in-situ' thermoelectric power and resistance measurements and simulations from first principles, the authors demonstrate that the cooperative occurrence of an electrochemically mediated charge transfer from the graphene to air, combined with the peculiar electronic structure of the graphene/SiC interface, explains the wide variation of measured conductivity and charge carrier type found in prior reports. digital.library.unt.edu/ark:/67531/metadc132974/
- Circuitry in Motion: Rhetoric(al) Moves in YouTube's Archive
- This article discusses rhetorical moves in YouTube's archive. The rhetorical effects of YouTube may be usefully demonstrated by looking briefly at the effects of YouTube on the 2008 U.S. presidential campaign. Whether YouTube videos invigorated campaigns or damned them, it is clear from the 2008 campaign that YouTube videos have come to play a significant role in authorizing arguments in American culture. digital.library.unt.edu/ark:/67531/metadc146584/
- CO₂ Reduction on Transition Metal (Fe, Co, Ni, and Cu) Surfaces: In Comparison with Homogeneous Catalysis
- This article discusses CO₂ reduction on transition metal (Fe, Co, Ni, and Cu) surfaces. Abstract: Reduction of CO₂ to CO on Fe, Co, Ni, and Cu surfaces has been studied using density functional theory (DFT) methods. Three reaction steps were studied: (a) adsorption of CO₂ (M + CO₂/M) (M = transition metal surface), (b) decomposition of CO₂ (CO₂/M = (CO + O)/M), and (c) desorption of CO ((CO + O)/M = O/M + CO). Binding energies and reaction energies were calculated using the generalized gradient approximation (GGA) via the Perdew-Burke-Ernzerhof (PBE) functional. Calculations show an interesting trend for reaction energies and total reaction barriers, as a function of metal: from Fe to Cu, reactions tend to be less exergonic; the metals earlier in the 3d series have lower total barriers for CO₂ reduction. However, "overbinding" of CO₂ on Fe causes a thermodynamic sink on the reaction coordinate, adn Co and Ni are more favorable in terms of a smaller fluctuation in reaction energies/barriers for these elementary catalytic steps. A Brønsted-Evans-Polanyi (BEP) relationship was analyzed for C-O bond scission of CO₂ on the metal surfaces. Heterogeneous catalysis is also compared with the homogeneous models using transition metal β-diketiminato complexes, showing that both heterogeneous and homogeneous catalysis of CO₂ reduction display the same energetic trend as a function of metal. digital.library.unt.edu/ark:/67531/metadc107801/
- Coherent control of atomic excitation using off-resonant strong few-cycle pulses
- This article discusses coherent control of atomic excitation using off-resonant strong few-cycle pulses. Abstract: We study the dynamics of a two-level system driven by an off-resonance few-cycle pulse which has a phase jump ø at t = t₀, in contrast to many-cycle pulses, under the nonrotating-wave approximation (NRWA). We give a closed form analytical solution for the evolution of the probability amplitude |Cₐ(t)| for the upper level. Using the appropriate pulse parameters like the phase jump ø, jump time t₀, pulse width Շ, frequency ν, and Rabi frequency Ώ₀ the population transfer after the pulse is gone can be optimized and, for the pulse considered here, an enhancement factor of 10⁶-10⁸ was obtained. digital.library.unt.edu/ark:/67531/metadc103266/
- Coherent control of refractive index in far-detuned Λ systems
- This article discusses the coherent control of refraction index in far-detuned Λ systems. Abstract: Enhancement and control of the index of refraction in a mixture of two three-level atomic species that form a pair of far-detuned Λ schemes under two-photon resonance and has been studied. We employ the density-matrix approach to properly take population relaxation into account and to describe the interaction of each Λ system with the electromagnetic fields. Both Λ systems are driven by a corresponding far-detuned coherent field at one atomic transition and are probed by the same weak field. In the dressed-state basis, it represents a superposition of effective two-level subsystems with the positions, widths, and amplitudes of the resonances controlled by the driving fields and allows for efficient control of the susceptibility of the total system; leading to refractive index (RI) enhancement with vanishing absorption in the absence of amplification. We analyze the experimental implementation of such a system in a cell of Rb atoms with a natural abundance of isotopes. An upper limit estimate of the RI enhancement is obtained. digital.library.unt.edu/ark:/67531/metadc103270/
- Coherent excitation of a two-level atom driven by a far-off-resonant classical field: Analytical solutions
- This article discusses the coherent excitation of a two-level atom driven by a far-off-resonant classical field. Abstract: We present an analytical treatment of coherent excitation of a two-level atom driven by a far-off-resonant classical field. A class of pulse envelope is obtained for which this problem is exactly solvable. The solutions are given in terms of the Heun function, which is a generalization of the hypergeometric function. Degeneracy of the Heun to a hypergeometric equation can give all the exactly solvable pulse shapes of Gauss hypergeometric form from the generalized pulse shape obtained here. We discuss the application of the results obtained to the generation of soft x-ray and ultraviolet radiations. digital.library.unt.edu/ark:/67531/metadc103262/
- Comparative Assessment of Peer Review (CAPR): EU/US workshop on peer review: Assessing "broader impact" in research grant applications
- This is the report of a workshop focusing on the use of broader societal impacts criteria as part of the review process at the European Commission. There is both a historical account and some thinking about how 'impact' ought to be incorporated into Horizon 2020 (the funding scheme formerly known as FP8). Since the US NSF is also currently rethinking the details of its merit review process, and since there is an interesting comparison between NSF's and the EC's approaches to impact, the authors have also included a focus on NSF's Broader Impacts Criterion. The workshop was both a research opportunity (under SciSIP grant #0830387) and an effort to use that research to help inform policy for science (in terms of informing peer review models). digital.library.unt.edu/ark:/67531/metadc86179/
- Comparative Assessment of Peer Review: Project Outcomes Report
- This report discusses the Comparative Assessment of Peer Review (CAPR) project outcomes. Public funding agencies are required to demonstrate accountability to their government funders (e.g., Congress) as well as to the public. Some agencies - including the US National Science Foundation (NSF) - have used broader societal impacts criteria as part of the review process of grant proposals in order to connect scientific research to societal needs. But these agencies have often encountered questions from scientists and engineers for how to integrate such demands for broader societal impacts into their research proposals. In an effort to help clarify the idea of broader impacts, in 2010 NSF and Congress proposed a list of national needs that NSF-funded research would be required to meet. But was this the best solution? This report discusses the authors' research. digital.library.unt.edu/ark:/67531/metadc139466/
- Complex Materials for Molecular Spintronics Applications: Cobalt Bis(dioxolene) Valence Tautomers, from Molecules to Polymers
- This article discusses complex materials for molecular spintronics applications. Abstract: Using first principles calculations, the authors predict a complex multifunctional behavior in cobalt bis(dioxolene) valence tautomeric compounds. Molecular spin-state switching is shown to dramatically alter electronic properties and corresponding transport properties. This spin state dependence has been demonstrated for technologically relevant coordination polymers of valence tautomers as well as for novel conjugated polymers with valence tautomeric functionalization. As a result, these materials are proposed as promising candidates for spintronic devices that can couple magnetic bistability with novel electrical and spin conduction properties. The authors' findings pave the way to the fundamental understanding and future design of active multifunctional organic materials for spintronics applications. digital.library.unt.edu/ark:/67531/metadc132994/
- Computational criteria for establishing reflex from plasticity to hardwiring
- This article accompanies a poster presentation on computational criteria for establishing reflex from plasticity to hardwiring. The role of synaptic plasticity in associative learning has been explored extensively computationally. Yet, the computational mechanism for hardwiring of the neural circuit has only been addressed recently using a systems approach of whole-animal behavior based on an evolutionary process for survival. In this paper, the authors will explore the computational criteria needed to establish the hardwiring of reflex. digital.library.unt.edu/ark:/67531/metadc122150/
- Contributing factors in judgement of fairness by monetary value
- This article accompanies a poster presentation on contributing factors in judgement of fairness by monetary value. Given that the authors have developed for emotional response (Emotional-Gain Model) and a model for fairness (Fairness-Equity Model) that quantified emotional bias and fairness bias, the authors will use these models to reveal the hidden factors contributing to the emotional bias and fairness bias. Using the Ultimatum Game (UG) with human subjects to split a sum of money, the authors compare the responses between sharing $10 vs. $10 million. digital.library.unt.edu/ark:/67531/metadc122155/
- Control of Root Architecture and Nodulation by the LATD/NIP Transporter
- This article discusses root architecture and nodulation. Abstract: The Medicago truncatula LATD/NIP gene is essential for the development of lateral and primary root and nitrogen-fixing nodule meristems as well as for rhizobial invasion of nodules. LATD/NIP encodes a member of the NRT1(PTR1) nitrate and di-and tri-peptide transporter family, suggesting that its function is to transport one of these or another compound(s). Because latd/nip mutants can have their lateral and primary root defects rescued by ABA, ABA is a potential substrate for transport. LATD/NIP expression in the root meristem was demonstrated to be regulated by auxin, cytokinin and abscisic acid, but not by nitrate. LATD/NIP's potential function and its role in coordinating root architecture and nodule formation are discussed. digital.library.unt.edu/ark:/67531/metadc40391/
- Controllable enhanced dragging of light in ultradispersive media
- This article discusses controllable enhanced dragging of light in ultradispersive media. Abstract: We have theoretically demonstrated an enhanced Fizeau effect due to dragging the light that occurs when the group velocity of light is ultraslow. The proposed experiment can be done in a cell of atomic Rb vapor under conditions such that the group velocity of light is of the order of a few hundred meters per second. We show theoretically that higher-order dispersion can influence the Fizeau effect and can be observed experimentally. It has been shown that the change of phase is sensitive to the motion of the cell with the speed of the order of 10⁻³ cm/s and for possible displacements as small as 10 Å. The enhanced dragging effect can be applied for position control, detection of slow mechanical motion, and efficient modulators of light. digital.library.unt.edu/ark:/67531/metadc103255/
- Cooperation in neural systems: Bridging complexity and periodicity
- This article discusses cooperation in neural systems. Abstract: Inverse power law distributions are generally interpreted as a manifestation of complexity, and waiting time distributions with power index μ < 2 reflect the occurrence of ergodicity-breaking renewal events. In this paper we show how to combine these properties with the apparently foreign clocklike nature of biological processes. We use a two-dimensional regular network of leaky integrate-and-fire neurons, each of which is linked to its four nearest neighbors, to show that both complexity and periodicity are generated by locality breakdown: Links of increasing strength have the effect of turning local interactions into long-range interactions, thereby generating time complexity followed by time periodicity. Increasing the density of neuron firings reduces the influence of periodicity, thus creating a cooperation-induced renewal condition that is distinctly non-Poissonian. digital.library.unt.edu/ark:/67531/metadc132986/
- Cooperation-induced topological complexity: a promising road to fault tolerance and Hebbian learning
- This article discusses cooperation-induced topological complexity. Abstract: According to an increasing number of researchers intelligence emerges from criticality as a consequence of locality breakdown and long-range correlation, well known properties of phase transition processes. The authors study a model of interacting units, as an idealization of real cooperative systems such as the brain or a flock of birds, for the purpose of discussing the emergence of long-range correlation from the coupling of any unit with its nearest neighbors. The authors focus on the critical condition that has been recently shown to maximize information transport and the authors study the topological structure of the network of dynamically linked nodes. Although the topology of this network depends on the arbitrary choice of correlation threshold, namely the correlation intensity selected to establish a link between two nodes; the numerical calculations of this paper afford some important indications on the dynamically induced topology. The first important property is the emergence of a perception length as large as the flock size, thanks to some nodes with a large number of links, thus playing the leadership role. All the units are equivalent and leadership moves in time from one to another set of nodes, thereby insuring fault tolerance. Then the authors focus on the correlation threshold generating a scale-free topology with power index v ≈ 1 and the authors find that if this topological structure is selected to establish consensus through the linked nodes, the control parameter necessary to generate criticality is close to the critical value corresponding to the all-to-all coupling condition. The authors find that criticality in this case generates also a third state, corresponding to a total lack of consensus. However, the authors make a numerical analysis of the dynamically induced network, and the authors find that it consists of two almost independent structures, each of which is equivalent to a network in the all-to-all coupling condition. This observation confirms that cooperation makes the system evolve toward favoring consensus topological structures. The authors argue that these results are compatible with both Hebbian learning and fault tolerance. digital.library.unt.edu/ark:/67531/metadc132972/
- Cooperative Effects in the Annelation of Benzene by Multiple Etheno Groups
- This article discusses cooperative effects in the annelation of benzene by multiple etheno groups. Abstract: The results of B3LYP/6-31G(d) calculations show that there is a strong cooperative effect on the energies that result from annelating benzene with 1, 2, and 3 etheno groups, to form 3, 4, and 5 respectively. The etheno annelation energies have been decomposed into two major contributors - etheno annelation, with all the bonds in the six-membered ring constrained to have the same C-C bond length as in D6h benzene, and optimization of the C-C bond lengths in the annelated benzene ring. The energies computed for each of these two steps show that the etheno groups behave cooperatively in both of them. The origin of the cooperativity, calculated for each step, is described and discussed. digital.library.unt.edu/ark:/67531/metadc71793/
- Correlation of solute transfer into alkane solvents from water and from the gas phase with updated Abraham model equations
- This article discusses the correlation of solute transfer into alkane solvents from water and from the gas phase with updated Abraham model equations. Abstract: Literature data regarding partitioning of compounds from the gas phase to alkanes and from water to alkanes have been compiled and analyzed in accord with the Abraham solvation parameter model. Mathematical correlations have been developed for describing the partitioning behavior of organic solutes and gases into hexane, heptane, octane and decane. Derived mathematical expressions were found to predict the available partition coefficient data to within 0.15 log units or better. digital.library.unt.edu/ark:/67531/metadc152452/
- Correlation of Solute Transfer Into Toluene and Ethylbenzene from Water and from the Gas Phase Based on the Abraham Model
- This article discusses correlation of solute transfer into toluene and ethylbenzene from water and from the gas phase based on the Abraham model. Experimental data have been compiled from the published literature on the partition coefficients of solutes and vapors into ethylbenzene and toluene at 298 K. The logarithms of the water-to-ethylbenzene and water-to-toluene partition coefficients, log P, and gas-to-ehtylbenzene and gas-to-toluene partition coefficients, log K, were correlated with the Abraham solvation parameter model. The derived mathematical expressions described the observed log P and log K data for the two aromatic hydrocarbon solvents to within average deviations of 0.13 log units or less. digital.library.unt.edu/ark:/67531/metadc152451/
- Criticality and Transmission of Information in a Swarm of Cooperative Units
- This article discusses criticality and transmission of information in a swarm of cooperative units. Abstract: We show that the intelligence of a swarm of cooperative units (birds) emerges at criticality, as an effect of the joint action of frequent organizational collapses and of spatial correlation as extended as the flock size. The organizational collapses make the birds become independent of one another, thereby allowing the flock to follow the direction of the lookout birds. Long-range correlation violates the principle of locality, making the lookout birds transmit information on either danger or resources with a time delay determined by the time distance between two consecutive collapses. digital.library.unt.edu/ark:/67531/metadc40392/
- Current Applications of Computational Chemistry in JACS - Molecules, Mechanisms, and Materials
- This article discusses current applications of computational chemistry. This virtual issue of JACS Select is devoted to some of the computation chemistry that has recently been published in the Journal of the American Chemical Society (JACS). The 25 articles and Communications that appear in this issue of JACS Select were chosen on the basis of the enthusiasm of the referees for these manuscripts when they were reviewed, as well as on the number of times each of these articles has been accessed online since its publication. Diversity of subject matter was not a criterion used in selecting these 25 articles from the ca. 50 well-reviewed, frequently accessed articles that were initially considered. However, inspection of the list of the subjects covered - from amyloid fibril polymorphism to nucleation of amorphous calcium carbonate; from the structure of solid Li(NH3)4 to the role that solvation plays in the Thorpe-Ingold effect; and to the nonstatistical, gas-phase dynamics of [1,5] hydrogen shifts in chemically activated cyclopentadiene - reveals the diverse nature of some of the best papers in computational chemistry that have been published recently in JACS. digital.library.unt.edu/ark:/67531/metadc71807/
- Current Behavioral and Psychosocial Interventions for HIV/AIDS
- This presentation is part of the faculty lecture series UNT Speaks Out on AIDS. This presentation discusses recent directions in psychosocial research on HIV/AIDS in the United States. digital.library.unt.edu/ark:/67531/metadc71782/
- Cyclooctatetraenes Tetrakis-Annelated with α-Dithio- or α-Diselenocarbonyl Groups: Diradicals Predicted To Have Ground States with 10 π Electrons in the Eight-Membered Ring and Two-Center, Three-Electron, σ Bonds between Two Pairs of Chalcogen Atoms
- This article discusses cyclooctatetraenes. Abstract: (U)B3LYP calculations with the 6-31+G(d) and 6-311+G(2df) basis sets have been carried out on cyclooctatetraenes 6 and 7, in which the COT ring is tetrakis-annelated with α-dithio- or α-diselenocarbonyl groups. Transferring two electrons from the high-lying b1g and eu σ MOs in 6 and 7 into the unoccupied, nonbonding, COT π orbital is computed to be energetically favorable. The lowest D4h electronic state is calculated to be 3Eu, which formally contains 10 π electrons in the eight-membered ring and has two unpaired electrons in σ MOs. The 3Eu state undergoes a first-order Jahn-Teller distortion to form 6d and 7d, in which the pair of one-electron holes in the σ MOs is stabilized by the formation of two, two-center, three-electron bonds between pairs of chalcogen atoms that are diagonally across the eight-membered ring from each other. The corresponding open-shell singlets are computed to be about 1 kcal/mol lower in energy than the Jahn-Teller distorted triplets. Molecules 6i and 7i, in which the C-C bond in one four-membered ring is cleaved, are computed to be lower in energy than 6d and 7d. However, a substantial barrier is predicted to separate each of the two pairs of isomers so that 6d and 7d should, at least in principle, be isolable. digital.library.unt.edu/ark:/67531/metadc71813/
- A cytochrome P450 monooxygenase commonly used for negative selection in transgenic plants causes growth anomalies by disrupting brassinosteroid signaling
- This article discusses a cytochrome P450 monooxygenase. Abstract: Background: Cytochrome P450 monooxygenases form a large superfamily of enzymes that catalyze diverse reactions. The P450su1 gene from the soil bacteria Streptomyces griseolus encodes CYP105A1 which acts on various substrates including sulfonylurea herbicides, vitamin D, coumarins, and based on the work presented here, brassinosteroids. P450su1 is used as a negative-selection marker in plants because CYP105A1 converts the relatively benign sulfonyl urea pro-herbicide R7402 into a highly phytotoxic product. Consistent with its use for negative selection, transgenic Arabidopsis plants were generated with P450su1 situated between recognition sequences for FLP recombinase from yeast to select for recombinase-mediated excision. However, unexpected and prominent developmental aberrations resembling those described for mutants defective in brassinosteroid signaling were observed in many of the lines. Results: The phenotypes of the most affected lines included severe stunting, leaf curling, darkened leaves characteristic of anthocyanin accumulation, delayed transition to flowering, low pollen and seed yields, and delayed senescence. Phenotype severity correlated with P450su1 transcript abundance, but not with transcript abundance of other experimental genes, strongly implicating CYP105A1 as responsible for the defects. Germination and seedling growth of transgenic and control lines in the presence and absence of 24-epibrassinolide indicated that CYP105A1 disrupts brassinosteroid signaling, most likely by inactivating brassinosteroids. Conclusions: Despite prior use of this gene as a genetic tool, deleterious growth in the absence of R7402 has not been elaborated. The authors show that this gene can cause aberrant growth by disrupting brassinosteroid signaling and affecting homeostasis. digital.library.unt.edu/ark:/67531/metadc81383/
- Dear Facebook
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Access: Use of this item is restricted to the UNT Community.
This book chapter is written in the form of a break-up letter from the author to the social networking website, Facebook. It discusses social networking, technological changes, urbanization, globalization, media technology, and philosophical ideas about society. digital.library.unt.edu/ark:/67531/metadc83329/ - Derivation of the evolution of empathic other-regarding social emotions as compared to non-social self-regarding emotions
- This article accompanies a poster presentation on the derivation of the evolution of empathic other-regarding social emotions as compared to non-social self-regarding emotions. The present study derives the evolution of social emotions by inclusion of other-regarding concerns from the non-social emotions of self-regarding concerns. Emotional processing is a self-discovered error-correction feedback process in which computations are involved to assess the accuracy of the internal brain-generated predictions with respect to the reality, in order to increase its probability of an organism's own survival. digital.library.unt.edu/ark:/67531/metadc122156/
- Development of Abraham model correlations for solvation characteristics of secondary and branched alcohols
- This article discusses the development of Abraham model correlations for solvation characteristics of secondary and branched alcohols. Abstract: Data have been compiled from the published literature on the partition coefficients of solutes and vapors into the anhydrous secondary and branched alcohols (2-propanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol and 3-methyl-1-butanol) from both water and from the gas phase. The logarithms of the water-to-alcohol partition coefficents (log P) and gas-to-alcohol partition coefficients (log K) were correlated with the Abraham solvation parameter model. The derived correlations described the observed log P and log K values to within average standard deviations of 0.14 and 0.13 log units, respectively. The predictive abilities of the each correlation were assessed by dividing databases into a separate training set and test set. digital.library.unt.edu/ark:/67531/metadc155632/