Ince-Gaussian series representation of the two-dimensional fractional Fourier transform.

PubMed

Bandres, Miguel A; Gutiérrez-Vega, Julio C

2005-03-01

We introduce the Ince-Gaussian series representation of the two-dimensional fractional Fourier transform in elliptical coordinates. A physical interpretation is provided in terms of field propagation in quadratic graded-index media whose eigenmodes in elliptical coordinates are derived for the first time to our knowledge. The kernel of the new series representation is expressed in terms of Ince-Gaussian functions. The equivalence among the Hermite-Gaussian, Laguerre-Gaussian, and Ince-Gaussian series representations is verified by establishing the relation among the three definitions.

A linear quadratic Gaussian with loop transfer recovery proximity operations autopilot for spacecraft. M.S. Thesis - MIT

NASA Technical Reports Server (NTRS)

Chen, George T.

1987-01-01

An automatic control scheme for spacecraft proximity operations is presented. The controller is capable of holding the vehicle at a prescribed location relative to a target, or maneuvering it to a different relative position using straight line-of-sight translations. The autopilot uses a feedforward loop to initiate and terminate maneuvers, and for operations at nonequilibrium set-points. A multivariate feedback loop facilitates precise position and velocity control in the presence of sensor noise. The feedback loop is formulated using the Linear Quadratic Gaussian (LQG) with Loop Transfer Recovery (LTR) design procedure. Linear models of spacecraft dynamics, adapted from Clohessey-Wiltshire Equations, are augmented and loop shaping techniques are applied to design a target feedback loop. The loop transfer recovery procedure is used to recover the frequency domain properties of the target feedback loop. The resulting compensator is integrated into an autopilot which is tested in a high fidelity Space Shuttle Simulator. The autopilot performance is evaluated for a variety of proximity operations tasks envisioned for future Shuttle flights.

The Linear Quadratic Gaussian Multistage Game with Nonclassical Information Pattern Using a Direct Solution Method

NASA Astrophysics Data System (ADS)

Clemens, Joshua William

Game theory has application across multiple fields, spanning from economic strategy to optimal control of an aircraft and missile on an intercept trajectory. The idea of game theory is fascinating in that we can actually mathematically model real-world scenarios and determine optimal decision making. It may not always be easy to mathematically model certain real-world scenarios, nonetheless, game theory gives us an appreciation for the complexity involved in decision making. This complexity is especially apparent when the players involved have access to different information upon which to base their decision making (a nonclassical information pattern). Here we will focus on the class of adversarial two-player games (sometimes referred to as pursuit-evasion games) with nonclassical information pattern. We present a two-sided (simultaneous) optimization solution method for the two-player linear quadratic Gaussian (LQG) multistage game. This direct solution method allows for further interpretation of each player's decision making (strategy) as compared to previously used formal solution methods. In addition to the optimal control strategies, we present a saddle point proof and we derive an expression for the optimal performance index value. We provide some numerical results in order to further interpret the optimal control strategies and to highlight real-world application of this game-theoretic optimal solution.

The CEO Speaks.

ERIC Educational Resources Information Center

Isherwood, Geoffrey B.; And Others

1984-01-01

Reports results of a 1982-83 survey of 37 Canadian chief executive school officers (CEOs) regarding their effectiveness. Presents findings and analysis regarding CEO relationships and effectiveness with community groups and school board members, community expectations of CEOs, CEO roles as mediators and policy makers, and reasons for…

Non-Gaussian lineshapes and dynamics of time-resolved linear and nonlinear (correlation) spectra.

PubMed

Dinpajooh, Mohammadhasan; Matyushov, Dmitry V

2014-07-17

Signatures of nonlinear and non-Gaussian dynamics in time-resolved linear and nonlinear (correlation) 2D spectra are analyzed in a model considering a linear plus quadratic dependence of the spectroscopic transition frequency on a Gaussian nuclear coordinate of the thermal bath (quadratic coupling). This new model is contrasted to the commonly assumed linear dependence of the transition frequency on the medium nuclear coordinates (linear coupling). The linear coupling model predicts equality between the Stokes shift and equilibrium correlation functions of the transition frequency and time-independent spectral width. Both predictions are often violated, and we are asking here the question of whether a nonlinear solvent response and/or non-Gaussian dynamics are required to explain these observations. We find that correlation functions of spectroscopic observables calculated in the quadratic coupling model depend on the chromophore's electronic state and the spectral width gains time dependence, all in violation of the predictions of the linear coupling models. Lineshape functions of 2D spectra are derived assuming Ornstein-Uhlenbeck dynamics of the bath nuclear modes. The model predicts asymmetry of 2D correlation plots and bending of the center line. The latter is often used to extract two-point correlation functions from 2D spectra. The dynamics of the transition frequency are non-Gaussian. However, the effect of non-Gaussian dynamics is limited to the third-order (skewness) time correlation function, without affecting the time correlation functions of higher order. The theory is tested against molecular dynamics simulations of a model polar-polarizable chromophore dissolved in a force field water.

Quadratic correlation filters for optical correlators

NASA Astrophysics Data System (ADS)

Mahalanobis, Abhijit; Muise, Robert R.; Vijaya Kumar, Bhagavatula V. K.

2003-08-01

Linear correlation filters have been implemented in optical correlators and successfully used for a variety of applications. The output of an optical correlator is usually sensed using a square law device (such as a CCD array) which forces the output to be the squared magnitude of the desired correlation. It is however not a traditional practice to factor the effect of the square-law detector in the design of the linear correlation filters. In fact, the input-output relationship of an optical correlator is more accurately modeled as a quadratic operation than a linear operation. Quadratic correlation filters (QCFs) operate directly on the image data without the need for feature extraction or segmentation. In this sense, the QCFs retain the main advantages of conventional linear correlation filters while offering significant improvements in other respects. Not only is more processing required to detect peaks in the outputs of multiple linear filters, but choosing a winner among them is an error prone task. In contrast, all channels in a QCF work together to optimize the same performance metric and produce a combined output that leads to considerable simplification of the post-processing. In this paper, we propose a novel approach to the design of quadratic correlation based on the Fukunaga Koontz transform. Although quadratic filters are known to be optimum when the data is Gaussian, it is expected that they will perform as well as or better than linear filters in general. Preliminary performance results are provided that show that quadratic correlation filters perform better than their linear counterparts.

Perceptions of hospital CEOs about the effects of CEO turnover.

PubMed

Khaliq, Amir A; Thompson, David M; Walston, Stephen L

2006-01-01

Empirical evidence is scarce on chief executive officer (CEO) turnover in U.S. hospitals, with potentially serious implications for many of these organizations. This study, based on a nationwide survey of CEOs at non-federal general surgical and medical community hospitals conducted in the spring of 2004, reports the perceptions of hospital CEOs regarding the circumstances and impact of CEO turnover on U.S. hospitals. In the opinion of the respondents, the impact includes competitors taking advantage of turnover by luring employees and physicians away from the target hospital, significantly increasing the likelihood of other senior executives leaving the hospital, and many of the important strategic activities being delayed or cancelled altogether. Interestingly, the perceptions of CEOs regarding the effects of turnover do not seem to differ regardless of voluntary or involuntary circumstances of turnover. However, there is a notable bias in emphasizing the perceived negative implications of respondents' own departures and allegedly positive effects of their predecessors' departures.

The CEO's real legacy.

PubMed

Freeman, Kenneth W

2004-11-01

The literature on CEO succession planning is nearly unanimous in its advice: Begin early, look first inside your company for exceptional talent, see that candidates gain experience in all aspects of the business, and help them develop the skills they will need in the top job. It all makes sense and sounds pretty straightforward. Nevertheless, the list of CEOs who last no more than a few years on the job continues to grow. Implicit in many, if not all, of these unceremonious departures is the absence of an effective CEO succession plan. The problem is, most boards simply don't want to talk about CEO succession: Why rock the boat when things are going well? Why risk offending the current CEO? Meanwhile, most CEOs can't imagine that anyone could adequately replace them. In this article, Kenneth W. Freeman, the retired CEO of Quest Diagnostics, discusses his own recent handoff experience (Surya N. Mohapatra became chief executive in May 2004) and offers his approach to succession planning. He says it falls squarely on the incumbent CEO to put ego aside and initiate and actively manage the process of selecting and grooming a successor. Aggressive succession planning is one of the best ways for CEOs to ensure the long-term health of the company, he says. Plus, thinking early and often about a successor will likely improve the chief executive's performance during his tenure. Freeman advocates the textbook rules for succession planning but adds to that list a few more that apply specifically to the incumbent CEO: Insist that the board become engaged in succession planning, look for a successor who is different from you, and make the successor's success your own. After all, Freeman argues, the CEO's true legacy is determined by what happens after he leaves the corner office.

Renyi entropy measures of heart rate Gaussianity.

PubMed

Lake, Douglas E

2006-01-01

Sample entropy and approximate entropy are measures that have been successfully utilized to study the deterministic dynamics of heart rate (HR). A complementary stochastic point of view and a heuristic argument using the Central Limit Theorem suggests that the Gaussianity of HR is a complementary measure of the physiological complexity of the underlying signal transduction processes. Renyi entropy (or q-entropy) is a widely used measure of Gaussianity in many applications. Particularly important members of this family are differential (or Shannon) entropy (q = 1) and quadratic entropy (q = 2). We introduce the concepts of differential and conditional Renyi entropy rate and, in conjunction with Burg's theorem, develop a measure of the Gaussianity of a linear random process. Robust algorithms for estimating these quantities are presented along with estimates of their standard errors.

Voluntary transition of the CEO: owner CEOs' sense of self before, during and after transition

PubMed Central

Byrnes, Randy T.; Taylor, Scott N.

2015-01-01

This inductive study explores how former business owner chief executive officers (CEOs) experience sense of self during voluntary separation and transition from their company. Our inquiry engaged 16 CEOs who ran companies ranging in size from 15 to 500 employees as they detailed their stories of walking away from roles as owner CEOs. We developed a coding scheme to analyze themes manifested in the narratives. We also analyzed the former CEOs' narratives using a stage and valence model depicting both the continuum of the separation experience and the characterization of each stage as a positive or negative state of being. The diverse yet synchronous stories resulted in three implications for current owner CEOs, professionals who advise CEOs, and future research on CEOs' careers. First, the CEOs often failed to allocate sufficient time and effort to prepare for an identity shift following the sale of their company or transition into retirement. Second, the CEOs experienced a diminished sense of self and dissatisfaction with the exit event. Third, the majority of the CEOs demonstrated an ability to work through the adverse and unanticipated states of being into a positive sense of self. PMID:26579018

Voluntary transition of the CEO: owner CEOs' sense of self before, during and after transition.

PubMed

Byrnes, Randy T; Taylor, Scott N

2015-01-01

This inductive study explores how former business owner chief executive officers (CEOs) experience sense of self during voluntary separation and transition from their company. Our inquiry engaged 16 CEOs who ran companies ranging in size from 15 to 500 employees as they detailed their stories of walking away from roles as owner CEOs. We developed a coding scheme to analyze themes manifested in the narratives. We also analyzed the former CEOs' narratives using a stage and valence model depicting both the continuum of the separation experience and the characterization of each stage as a positive or negative state of being. The diverse yet synchronous stories resulted in three implications for current owner CEOs, professionals who advise CEOs, and future research on CEOs' careers. First, the CEOs often failed to allocate sufficient time and effort to prepare for an identity shift following the sale of their company or transition into retirement. Second, the CEOs experienced a diminished sense of self and dissatisfaction with the exit event. Third, the majority of the CEOs demonstrated an ability to work through the adverse and unanticipated states of being into a positive sense of self.

Ending the CEO succession crisis.

PubMed

Charan, Ram

2005-02-01

The CEO succession process is broken. Many companies have no meaningful succession plans, and few of the ones that do are happy with them. CEO tenure is shrinking; in fact, two out of five CEOs fail in their first 18 months. It isn't just that more CEOs are being replaced; it's that they're being replaced badly. The problems extend to every aspect of CEO succession: internal development programs, board supervision, and outside recruitment. While many organizations do a decent job of nurturing middle managers, few have set up the comprehensive programs needed to find the half-dozen true CEO candidates out of the thousands of leaders in their midst. Even more damaging is the failure of boards to devote enough attention to succession. Search committee members often have no experience hiring CEOs; lacking guidance, they supply either the narrowest or the most general of requirements and then fail to vet eitherthe candidates or the recruiters. The result is that too often new CEOs are plucked from the well-worn Rolodexes of a remarkably small number of recruiters. These candidates may be strong in charisma but may lack critical skills or otherwise be a bad fit with the company. The resulting high turnover is particularly damaging, since outside CEOs often bring in their own teams, can cause the company to lose focus, and are especially costly to be rid of. Drawing on over 35 years of experience with CEO succession, the author explains how companies can create a deep pool of internal candidates, how boards can consistently align strategy and leadership development, and how directors can get their money's worth from recruiters. Choosing a CEO should be not one decision but an amalgam ofthousands of decisions made by many people every day over years.

Does CEO compensation impact patient satisfaction?

PubMed

Akingbola, Kunle; van den Berg, Herman A

2015-01-01

This study examines the relationship between CEO compensation and patient satisfaction in Ontario, Canada. The purpose of this paper is to determine what impact hospital CEO compensation has on hospital patient satisfaction. The analyses in this study were based on data of 261 CEO-hospital-year observations in a sample of 103 nonprofit hospitals. A number of linear regressions were conducted, with patient satisfaction as the dependent variable and CEO compensation as the independent variable of interest. Controlling variables included hospital size, type of hospital, and frequency of adverse clinical outcomes. CEO compensation does not significantly influence hospital patient satisfaction. Both patient satisfaction and CEO compensation appear to be driven primarily by hospital size. Patient satisfaction decreases, while CEO compensation increases, with the number of acute care beds in a hospital. In addition, CEO compensation does not even appear to moderate the influence of hospital size on patient satisfaction. There are several limitations to this study. First, observations of CEO-hospital-years in which annual nominal CEO compensation was below $100,000 were excluded, as they were not publicly available. Second, this research was limited to a three-year range. Third, this study related the compensation of individual CEOs to a measure of performance based on a multitude of patient satisfaction surveys. Finally, this research is restricted to not-for-profit hospitals in Ontario, Canada. The findings seem to suggest that hospital directors seeking to improve patient satisfaction may find their efforts frustrated if they focus exclusively on the hospital CEO. The findings highlight the need for further research on how CEOs may, through leading and supporting those hospital clinicians and staff that interact more closely with patients, indirectly enhance patient satisfaction. To the best of the authors' knowledge, no research has examined the relationship between

Do women CEOs face greater threat of shareholder activism compared to male CEOs? A role congruity perspective.

PubMed

Gupta, Vishal K; Han, Seonghee; Mortal, Sandra C; Silveri, Sabatino Dino; Turban, Daniel B

2018-02-01

We examine the glass cliff proposition that female CEOs receive more scrutiny than male CEOs, by investigating whether CEO gender is related to threats from activist investors in public firms. Activist investors are extraorganizational stakeholders who, when dissatisfied with some aspect of the way the firm is being managed, seek to change the strategy or operations of the firm. Although some have argued that women will be viewed more favorably than men in top leadership positions (so-called "female leadership" advantage logic), we build on role congruity theory to hypothesize that female CEOs are significantly more likely than male CEOs to come under threat from activist investors. Results support our predictions, suggesting that female CEOs may face additional challenges not faced by male CEOs. Practical implications and directions for future research are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Worse than enemies. The CEO's destructive confidant.

PubMed

Sulkowicz, Kerry J

2004-02-01

The CEO is often the most isolated and protected employee in the organization. Few leaders, even veteran CEOs, can do the job without talking to someone about their experiences, which is why most develop a close relationship with a trusted colleague, a confidant to whom they can tell their thoughts and fears. In his work with leaders, the author has found that many CEO-confidant relationships function very well. The confidants keep their leaders' best interests at heart. They derive their gratification vicariously, through the help they provide rather than through any personal gain, and they are usually quite aware that a person in their position can potentially abuse access to the CEO's innermost secrets. Unfortunately, almost as many confidants will end up hurting, undermining, or otherwise exploiting CEOs when the executives are at their most vulnerable. These confidants rarely make the headlines, but behind the scenes they do enormous damage to the CEO and to the organization as a whole. What's more, the leader is often the last one to know when or how the confidant relationship became toxic. The author has identified three types of destructive confidants. The reflector mirrors the CEO, constantly reassuring him that he is the "fairest CEO of them all." The insulator buffers the CEO from the organization, preventing critical information from getting in or out. And the usurper cunningly ingratiates himself with the CEO in a desperate bid for power. This article explores how the CEO-confidant relationship plays out with each type of adviser and suggests ways CEOs can avoid these destructive relationships.

CEO performance appraisal: review and recommendations.

PubMed

Newman, J F; Tyler, L; Dunbar, D M

2001-01-01

CEO performance appraisal (PA) is very valuable to an organization, but the chances of obtaining a PA of high quality decrease as executive responsibility increases. The realities of CEO PA are that it: (1) is inevitable; (2) is creative and complex; (3) involves politics; and (4) has a significant effect on the organization and the executive. PA is conducted for legal and social requirements, to enhance communication, to provide opportunities for improvement, and to relate performance to compensation. This article discusses several problems with chief executive officer (CEO) PA and the contemporary approaches that seek to improve it. Three fundamental areas for evaluation are identified: (1) organizational success; (2) areawide health status; and (3) professional role fulfillment. These provide an outline for successful healthcare PA. In addition to a discussion of the strategic considerations behind a successful CEO PA system, several recommendations are offered for the implementation of the annual evaluation process. The final goal of CEO PA is to link its results to CEO incentive compensation. It is strongly recommended that some portion of the CEO's salary directly hinge on his performance in two critical areas: organizational effectiveness and community health status.

Diversifying the Community College CEO Pipeline

ERIC Educational Resources Information Center

Perrakis, Athena; Campbell, D. Michael; Antonaros, Mary

2009-01-01

The authors examine the current community college presidential pipeline and offer possible explanations for poor CEO representation from diverse populations. They explore a relationship between CEO satisfaction and diversity by testing whether CEO satisfaction is correlated to campus and administrative diversity. While data from the study…

CEO Compensation and Hospital Financial Performance

PubMed Central

Reiter, Kristin L.; Sandoval, Guillermo A.; Brown, Adalsteinn D.; Pink, George H.

2010-01-01

Growing interest in pay-for-performance and the level of CEO pay raises questions about the link between performance and compensation in the health sector. This study compares the compensation of non-profit hospital Chief Executive Officers (CEOs) in Ontario, Canada to the three longest reported and most used measures of hospital financial performance. Our sample consisted of 132 CEOs from 92 hospitals between 1999 and 2006. Unbalanced panel data were analyzed using fixed effects regression. Results suggest that CEO compensation was largely unrelated to hospital financial performance. Inflation-adjusted salaries appeared to increase over time independent of hospital performance, and hospital size was positively correlated with CEO compensation. The apparent upward trend in salary despite some declines in financial performance challenges the fundamental assumption underlying this paper, that is, financial performance is likely linked to CEO compensation in Ontario. Further research is needed to understand long-term performance related to compensation incentives. PMID:19605619

CEO compensation and hospital financial performance.

PubMed

Reiter, Kristin L; Sandoval, Guillermo A; Brown, Adalsteinn D; Pink, George H

2009-12-01

Growing interest in pay-for-performance and the level of chief executive officers' (CEOs') pay raises questions about the link between performance and compensation in the health sector. This study compares the compensation of nonprofit hospital CEOs in Ontario, Canada to the three longest reported and most used measures of hospital financial performance. Our sample consisted of 132 CEOs from 92 hospitals between 1999 and 2006. Unbalanced panel data were analyzed using fixed effects regression. Results suggest that CEO compensation was largely unrelated to hospital financial performance. Inflation-adjusted salaries appeared to increase over time independent of hospital performance, and hospital size was positively correlated with CEO compensation. The apparent upward trend in salary despite some declines in financial performance challenges the fundamental assumption underlying this article, that is, financial performance is likely linked to CEO compensation in Ontario. Further research is needed to understand long-term performance related to compensation incentives.

Linear quadratic stochastic control of atomic hydrogen masers.

PubMed

Koppang, P; Leland, R

1999-01-01

Data are given showing the results of using the linear quadratic Gaussian (LQG) technique to steer remote hydrogen masers to Coordinated Universal Time (UTC) as given by the United States Naval Observatory (USNO) via two-way satellite time transfer and the Global Positioning System (GPS). Data also are shown from the results of steering a hydrogen maser to the real-time USNO mean. A general overview of the theory behind the LQG technique also is given. The LQG control is a technique that uses Kalman filtering to estimate time and frequency errors used as input into a control calculation. A discrete frequency steer is calculated by minimizing a quadratic cost function that is dependent on both the time and frequency errors and the control effort. Different penalties, chosen by the designer, are assessed by the controller as the time and frequency errors and control effort vary from zero. With this feature, controllers can be designed to force the time and frequency differences between two standards to zero, either more or less aggressively depending on the application.

AACC CEO Survey: Compensation

ERIC Educational Resources Information Center

Phillippe, Kent A.

2016-01-01

In 2015, the American Association of Community Colleges (AACC) conducted a survey of community college chief executive officers (CEOs) to collect their opinions on current issues, and gather information on their compensation. This report provides the results from this survey. The AACC CEO Survey was sent to 960 public community college presidents.…

Non-Gaussian bias: insights from discrete density peaks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desjacques, Vincent; Riotto, Antonio; Gong, Jinn-Ouk, E-mail: Vincent.Desjacques@unige.ch, E-mail: jinn-ouk.gong@apctp.org, E-mail: Antonio.Riotto@unige.ch

2013-09-01

Corrections induced by primordial non-Gaussianity to the linear halo bias can be computed from a peak-background split or the widespread local bias model. However, numerical simulations clearly support the prediction of the former, in which the non-Gaussian amplitude is proportional to the linear halo bias. To understand better the reasons behind the failure of standard Lagrangian local bias, in which the halo overdensity is a function of the local mass overdensity only, we explore the effect of a primordial bispectrum on the 2-point correlation of discrete density peaks. We show that the effective local bias expansion to peak clustering vastlymore » simplifies the calculation. We generalize this approach to excursion set peaks and demonstrate that the resulting non-Gaussian amplitude, which is a weighted sum of quadratic bias factors, precisely agrees with the peak-background split expectation, which is a logarithmic derivative of the halo mass function with respect to the normalisation amplitude. We point out that statistics of thresholded regions can be computed using the same formalism. Our results suggest that halo clustering statistics can be modelled consistently (in the sense that the Gaussian and non-Gaussian bias factors agree with peak-background split expectations) from a Lagrangian bias relation only if the latter is specified as a set of constraints imposed on the linear density field. This is clearly not the case of standard Lagrangian local bias. Therefore, one is led to consider additional variables beyond the local mass overdensity.« less

Blood conservation: the CEO perspective.

PubMed

Morgan, Timothy O

2004-08-01

Hospital CEOs are concerned about more than just cost of services to their patients. The advancement of patient car along with maintaining or improving patient safety are also key elements to the CEO, to limit patient risks, hospital liability, and negative public relations. The CEO is accountable to the hospital staff, the patients, and the general public. Establishing programs such as blood management or bloodless medicine can be implemented by using a team approach. A physician champion with a clear business plan that addresses all issues and challenges is critical for successful implementation. As blood and blood product costs rise and supply decreases, alternatives such as cell saving techniques and the use of pharmacologic interventions can have a significant impact on net hospital expenditures.

Exploring Corporate Rhetoric: Metadiscourse in the CEO's Letter.

ERIC Educational Resources Information Center

Hyland, Ken

1998-01-01

Examines how metadiscourse is used to create a positive corporate image in 137 CEOs' letters, showing how CEOs use nonpropositional material to realize rational, credible, and affective appeals. Reveals the essentially rhetorical nature of CEOs' letters by comparing the frequency and distribution of metadiscourse in their letters and directors'…

Quadratic Optimisation with One Quadratic Equality Constraint

DTIC Science & Technology

2010-06-01

This report presents a theoretical framework for minimising a quadratic objective function subject to a quadratic equality constraint. The first part of the report gives a detailed algorithm which computes the global minimiser without calling special nonlinear optimisation solvers. The second part of the report shows how the developed theory can be applied to solve the time of arrival geolocation problem.

Training the Revolving-Door CEO

ERIC Educational Resources Information Center

Dutton, Gail

2010-01-01

The revolving-door CEO is becoming a fixture of American companies, and is likely to remain so for some time. With executive tenure at a mere 2.5 years and a CEO turnover rate that increased 11 percent last year, newly hired executives must hit the ground running if they hope to be effective before moving on to their next jobs. Helping them adjust…

Job satisfaction among selected hospital CEOs.

PubMed

Matus, J C; Frazer, G H

1996-09-01

The purpose of this study was to identify the contributors to job satisfaction of hospital chief executive officers (CEOs) using a multidimensional approach of demographic characteristics. environmental traits, and person environment fit traits. By analyzing the concept of hospital executive job satisfaction in a multidimensional approach, a more comprehensive model of the most salient determinants of job satisfaction was developed. CEOs ranked their performance highest on employee and staff relations and managerial team building and lowest on information management systems. The results of this study can be used to better understand the intricacies and uniqueness of being a hospital CEO as well as the professional and personal requirements of success.

Self-Replicating Quadratics

ERIC Educational Resources Information Center

Withers, Christopher S.; Nadarajah, Saralees

2012-01-01

We show that there are exactly four quadratic polynomials, Q(x) = x [superscript 2] + ax + b, such that (x[superscript 2] + ax + b) (x[superscript 2] - ax + b) = (x[superscript 4] + ax[superscript 2] + b). For n = 1, 2, ..., these quadratic polynomials can be written as the product of N = 2[superscript n] quadratic polynomials in x[superscript…

The CEOS/GEO Constellation Concept

NASA Technical Reports Server (NTRS)

Cramer, Bryant; Ungar, Stephen

2007-01-01

The Constellation concept was first proposed during a discussion at the 19th CEOS Plenary, in London, in November 2005. The first Paper of the Constellation Concept was presented at the CEOS Strategic Implementation Team meeting (SIT-18), in Frascati, in March 2006, and strongly endorsed by the CEOS Principals. The concept attempts to provide agencies with tools for implementation of the elements that have been previously discussed in international forums (GEO Work Plan, GCOS Implementation Plan). This provides a solid foundation from the community providing requirements. Though agency spending is governed by national requirements, CEOS seeks synergies among member agency programs to fulfil GEOSS requirements, defining guidelines and standards to help agencies to determine from the outset what can be achieved. The constellations concept will allow the development of a commonalties approach among different agencies. At the heart of the application of the Constellations concept is the definition of a series of standards (specific to each Constellation) - required to be satisfied for any mission to be included in the constellation - and a process of recognition/acceptance, whereby an agency applies to SIT to have one or more of its missions (ideally from the outset of planning) recognised as meeting the constellation standards and thereby satisfying the relevant user community needs.

A model of voluntary turnover among hospital CEOs.

PubMed

Weil, P A; Kimball, P A

1995-01-01

This study examines factors contributing to hospital CEOs' voluntary decisions to leave their positions in 1990. Using a longitudinal design, we contrast 49 leavers with 1,362 stayers. We view turnover as influenced by both "push" factors that promote leaving (dissatisfaction with the position) and "hump" factors that need to be overcome (the cost of job change). Push factors giving rise to dissatisfaction include lower compensation, the predecessor's termination, and value incongruity between the CEO and the hospital. Testing the impact of key variables from Fiedler's contingency theory of leadership, we show that task-oriented leaders are relatively less satisfied when compared with relationship-oriented leaders. CEOs also express less satisfaction in low-situational control settings, a measure heavily influenced by perceived inadequate support from medical staff and subordinates. "Hump" factors that deterred leaving included family-related obstacles such as spouse's work or children's school, features mentioned most often by younger CEOs. The study suggests that boards should structure competitively paid positions with opportunities to generate support from the medical staff and subordinates. Recruiters for CEO positions are apprised of the importance of nonwork features in CEOs' willingness to consider new positions.

Quadratic Damping

ERIC Educational Resources Information Center

Fay, Temple H.

2012-01-01

Quadratic friction involves a discontinuous damping term in equations of motion in order that the frictional force always opposes the direction of the motion. Perhaps for this reason this topic is usually omitted from beginning texts in differential equations and physics. However, quadratic damping is more realistic than viscous damping in many…

Quadratic soliton self-reflection at a quadratically nonlinear interface

NASA Astrophysics Data System (ADS)

Jankovic, Ladislav; Kim, Hongki; Stegeman, George; Carrasco, Silvia; Torner, Lluis; Katz, Mordechai

2003-11-01

The reflection of bulk quadratic solutions incident onto a quadratically nonlinear interface in periodically poled potassium titanyl phosphate was observed. The interface consisted of the boundary between two quasi-phase-matched regions displaced from each other by a half-period. At high intensities and small angles of incidence the soliton is reflected.

Hospital CEO's viewpoint for future of health care marketing.

PubMed

Cox, V

1990-01-01

In summary, the CEOs have a wide variety of views on what role the marketer will play and what needs the marketer will fill for the CEO. It is important for the marketer to clarify the expected roles as they interview for jobs. Once in the position, it is important to keep communications open with the CEO to know the marketer's expected role.

WCDRR and the CEOS activities on disaters

NASA Astrophysics Data System (ADS)

Petiteville, I.; Ishida, C.; Danzeglocke, J.; Eddy, A.; Gaetani, F.; Frye, S.; Kuligowski, B.; Zoffoli, S.; Poland, M.; Jones, B.

2015-04-01

Agencies from CEOS (Committee on Earth Observation Satellites) have traditionally focused their efforts on the response phase. Rapid urbanization and increased severity of weather events has led to growing economic and human losses from disasters, requiring international organisations to act now in all disaster risk management (DRM) phases, especially through improved disaster risk reduction policies and programmes. As part of this effort, CEOS agencies have initiated a series of actions aimed at fostering the use of Earth observation (EO) data to support disaster risk reduction and at raising the awareness of policy and decision-makers and major stakeholders of the benefits of using satellite EO in all phases of DRM. CEOS is developing a long-term vision for sustainable application of satellite EO to all phases of DRM. CEOS is collaborating with regional representatives of the DRM user community, on a multi-hazard project involving three thematic pilots (floods, seismic hazards and volcanoes) and a Recovery Observatory that supports resilient recovery from one major disaster. These pilot activities are meant as trail blazers that demonstrate the potential offered by satellite EO for comprehensive DRM. In the framework of the 2015 3rd World Conference on Disaster Risk Reduction (WCDRR), the CEOS space agencies intend to partner with major stakeholders, including UN organizations, the Group on Earth Observations (GEO), international relief agencies, leading development banks, and leading regional DRM organisations, to define and implement a 15-year plan of actions (2015- 2030) that responds to high-level Post-2015 Framework for Disaster Risk Reduction priorities. This plan of action will take into account lessons learned from the CEOS pilot activities.

The last act of a great CEO.

PubMed

Friel, Thomas J; Duboff, Robert S

2009-01-01

No one is in a better position to get an incoming CEO up to speed than his or her predecessor, whose insights and accumulated wisdom are uniquely valuable during the transition and even beyond. The outgoing leader can provide information about the expectations of high-ranking employees; short-term opportunities ripe for harvesting; how the board and others perceive the newcomer's reputation or personal brand; the strengths and foibles of internal allies and external partners; organizational bench strength; and the wisdom that comes from experience well reflected upon. Organizations and their shareholders don't want intellectual capital like this to simply evaporate, which is why nearly every multinational corporation makes ongoing consultation a requirement in severance contracts and pays handsomely for it. Nevertheless, candid, in-depth discussions between outgoing and incoming CEOs rarely take place. Friel, formerly the chairman and CEO of Heidrick & Struggles, and Duboff, the CEO and a cofounder of HawkPartners, conducted numerous interviews with people who had been through at least one CEO transition to find out why those discussions didn't happen as a matter of course and how best to draw on the knowledge of a departing leader. They clearly outline the steps that organizations can take, such as making golden parachutes contingent on debriefing conversations, having HR arrange the meetings to dispel any awkwardness, and creating a thorough agenda. And they advise the two executives to meet as equals, share the "first 90 days plan," and speak consistently about the past and the future--to the media as well as to stakeholders. Much of an outgoing CEO's knowledge will be lost unless a conscious effort is made to capture it. As the average tenure of chief executives shrinks, it becomes increasingly imperative that they get off to a strong start.

CEO Sites Mission Management System (SMMS)

NASA Technical Reports Server (NTRS)

Trenchard, Mike

2014-01-01

Late in fiscal year 2011, the Crew Earth Observations (CEO) team was tasked to upgrade its science site database management tool, which at the time was integrated with the Automated Mission Planning System (AMPS) originally developed for Earth Observations mission planning in the 1980s. Although AMPS had been adapted and was reliably used by CEO for International Space Station (ISS) payload operations support, the database structure was dated, and the compiler required for modifications would not be supported in the Windows 7 64-bit operating system scheduled for implementation the following year. The Sites Mission Management System (SMMS) is now the tool used by CEO to manage a heritage Structured Query Language (SQL) database of more than 2,000 records for Earth science sites. SMMS is a carefully designed and crafted in-house software package with complete and detailed help files available for the user and meticulous internal documentation for future modifications. It was delivered in February 2012 for test and evaluation. Following acceptance, it was implemented for CEO mission operations support in April 2012. The database spans the period from the earliest systematic requests for astronaut photography during the shuttle era to current ISS mission support of the CEO science payload. Besides logging basic image information (site names, locations, broad application categories, and mission requests), the upgraded database management tool now tracks dates of creation, modification, and activation; imagery acquired in response to requests; the status and location of ancillary site information; and affiliations with studies, their sponsors, and collaborators. SMMS was designed to facilitate overall mission planning in terms of site selection and activation and provide the necessary site parameters for the Satellite Tool Kit (STK) Integrated Message Production List Editor (SIMPLE), which is used by CEO operations to perform daily ISS mission planning. The CEO team

Minutes of the Sixth CEOS Plenary Meeting

NASA Technical Reports Server (NTRS)

1993-01-01

The Committee on Earth Observations Satellites (CEOS) minutes for the sixth plenary meeting held in London, December 9-11, 1992 are presented. Attending as prospective members were the Russian Space Agency (RSA), the Committee for Hydrometeorology and Environmental Monitoring of the Ministry for Ecology and Natural resources of the Russian Federation (ROSCOMGIDROMET), the Chinese Academy of Space Technology (CAST) and the National Remote Sensing Center of China (NRSCC). Actions taken at the meeting included membership issues, CEOS proposals, data policy, and working group reports. Data requirements of CEOS affiliates were also reported on. Additional summations and statements as well as lists of participants and future meetings are included. In general, topics covered related to remote sensing and global change.

Vice President of Medical Affairs--moving on up to CEO?

PubMed

Tyler, J L

1999-01-01

Increasingly, physician executives are reaching the conclusion that if they choose, they may be viable candidates for CEO positions. While this opinion has merit, it must be tempered by marketplace realities. A fundamental issue for VPMAs aspiring to become CEOs is that they have little formalized training or education for CEO roles. Also, they may lack team-building skills--a critical success factor. Physician executives who seek out professional development opportunities that enhance both their interpersonal/management and "business" skills--accounting, finance, and planning--are more likely to be attractive candidates and succeed once they are in the position. Another consideration is that the CEO position usually has a precursor role--the COO. This position is the training ground for the CEO. Physician executives aspiring to be CEO will want to consider the following suggestions: (1) Make your intentions known; (2) groom your successor; (3) request a title change; (4) get your master's degree; (5) pursue professional development opportunities; (6) consider leaving the organization; and (7) talk with your family.

Non-Gaussian structure of B-mode polarization after delensing

NASA Astrophysics Data System (ADS)

Namikawa, Toshiya; Nagata, Ryo

2015-10-01

The B-mode polarization of the cosmic microwave background on large scales has been considered as a probe of gravitational waves from the cosmic inflation. Ongoing and future experiments will, however, suffer from contamination due to the B-modes of non-primordial origins, one of which is the lensing induced B-mode polarization. Subtraction of the lensing B-modes, usually referred to as delensing, will be required for further improvement of detection sensitivity of the gravitational waves. In such experiments, knowledge of statistical properties of the B-modes after delensing is indispensable to likelihood analysis particularly because the lensing B-modes are known to be non-Gaussian. In this paper, we study non-Gaussian structure of the delensed B-modes on large scales, comparing it with that of the lensing B-modes. In particular, we investigate the power spectrum correlation matrix and the probability distribution function (PDF) of the power spectrum amplitude. Assuming an experiment in which the quadratic delensing is an almost optimal method, we find that delensing reduces correlations of the lensing B-mode power spectra between different multipoles, and that the PDF of the power spectrum amplitude is well described as a normal distribution function with a variance larger than that in the case of a Gaussian field. These features are well captured by an analytic model based on the 4th order Edgeworth expansion. As a consequence of the non-Gaussianity, the constraint on the tensor-to-scalar ratio after delensing is degraded within approximately a few percent, which depends on the multipole range included in the analysis.

Gaussian variational ansatz in the problem of anomalous sea waves: Comparison with direct numerical simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruban, V. P., E-mail: ruban@itp.ac.ru

2015-05-15

The nonlinear dynamics of an obliquely oriented wave packet on a sea surface is analyzed analytically and numerically for various initial parameters of the packet in relation to the problem of the so-called rogue waves. Within the Gaussian variational ansatz applied to the corresponding (1+2)-dimensional hyperbolic nonlinear Schrödinger equation (NLSE), a simplified Lagrangian system of differential equations is derived that describes the evolution of the coefficients of the real and imaginary quadratic forms appearing in the Gaussian. This model provides a semi-quantitative description of the process of nonlinear spatiotemporal focusing, which is one of the most probable mechanisms of roguemore » wave formation in random wave fields. The system of equations is integrated in quadratures, which allows one to better understand the qualitative differences between linear and nonlinear focusing regimes of a wave packet. Predictions of the Gaussian model are compared with the results of direct numerical simulation of fully nonlinear long-crested waves.« less

Homogeneously dispersed CeO2 nanoparticles on exfoliated hexaniobate nanosheets

NASA Astrophysics Data System (ADS)

Marques, Thalles M. F.; Strayer, Megan E.; Ghosh, Anupama; Silva, Alexandre; Ferreira, Odair P.; Fujisawa, Kazunori; Alves da Cunha, Jose R.; Abreu, Guilherme J. P.; Terrones, Mauricio; Mallouk, Thomas E.; Viana, Bartolomeu C.

2017-12-01

Hexaniobate nanosheets derived from the parent compound K4Nb6O17 have been decorated with CeO2 nanoparticles by ion exchange with aqueous cerium (IV) solution. Very homogeneous CeO2 nanoparticle decoration of the hexaniobate sheets can be achieved by this method and the resulting composites may absorb visible light. HRTEM images show that ∼3.0 nm diameter CeO2 nanoparticles adhere to hexaniobate nanosheets that are exfoliated and then restacked prior to Ce deposition. The interfacial interaction between CeO2 nanoparticles and nanosheets would be due to an electrostatic attraction mechanism. Raman and XRD measurements have given strong evidence that CeO2 nanoparticles have fluorite structure. EDS, FTIR and XPS results suggest almost complete exchange of TBA+ and K+ by Ce4+. Cerium ion exchange on the acid exchanged parent compound, H2.9K1.1Nb6O17, revealed that the extent of Ce ion exchange is much greater in case of nanosheets, which may be rationalized by the larger surface area available after exfoliation. XPS measurements show that the ratio of Ce4+/Ce3+ is around 4.4, in agreement with the formation of fluorite structure (CeO2). Thus, these CeO2 nanoparticle/nanosheet composites may be useful for catalytic processes.

CEOS Committee on Earth Observations Satellites Consolidated Report, 1992

NASA Technical Reports Server (NTRS)

1992-01-01

A concise overview of the committee on Earth Observations Satellites (CEOS) and its Working Groups, covering the history and purpose of the Committee and its accomplishments to date are provided. The report will be updated annually before each Plenary meeting, and as developments in the Working Groups warrant. The committee on Earth Observations Satellites (originally named the International Earth Observations Satellite committee, IEOS) was treated in 1984, in response to a recommendation from the Economic Summit of Industrialized Nations Working Group on Growth, Technology, and Employment's Panel of Experts on Satellite Remote Sensing. This group recognized the multidisciplinary nature of satellite Earth observations, and the value of coordinating across all proposed missions. Thus, CEOS combined the previously existing groups for coordination on Ocean Remote-Sensing Satellites (CORSS) and coordination on Land Remote-Sensing Satellites (CLRSS), and established a broad framework for coordination across all spaceborne Earth observations missions. The first three LEOS Plenary meetings focused on treating and guiding the Working Groups deemed necessary to carry out the objectives of the CEOS members. After the third meeting, it was agreed that a more active orientation was required by the Plenary, and additional issues were brought before the group at the fourth meeting. At the fifth Plenary, international scientific programs and relevant intergovernmental organizations accepted invitations and participated as affiliate members of CEOS. This enabled progress toward integrating satellite data users' requirements into the CEOS process. Data exchange principles for global change research were also adopted. An interim CEOS Plenary meeting was held in April 1992, in preparation for the United Nations Conference on Environment and Development (UNCED). Brief encapsulations of the Plenary sessions immediately follow the Terms of Reference that govern the activities of CEOS as

Diffraction of a Gaussian beam in a three-dimensional smoothly inhomogeneous medium: an eikonal-based complex geometrical-optics approach.

PubMed

Berczynski, Pawel; Bliokh, Konstantin Yu; Kravtsov, Yuri A; Stateczny, Andrzej

2006-06-01

We present an ab initio account of the paraxial complex geometrical optics (CGO) in application to scalar Gaussian beam propagation and diffraction in a 3D smoothly inhomogeneous medium. The paraxial CGO deals with quadratic expansion of the complex eikonal and reduces the wave problem to the solution of ordinary differential equations of the Riccati type. This substantially simplifies the description of Gaussian beam diffraction as compared with full-wave or parabolic (quasi-optics) equations. For a Gaussian beam propagating in a homogeneous medium or along the symmetry axis in a lenslike medium, the CGO equations possess analytical solutions; otherwise, they can be readily solved numerically. As a nontrivial example we consider Gaussian beam propagation and diffraction along a helical ray in an axially symmetric waveguide medium. It is shown that the major axis of the beam's elliptical cross section grows unboundedly; it is oriented predominantly in the azimuthal (binormal) direction and does not obey the parallel-transport law.

Quantum steering of Gaussian states via non-Gaussian measurements

NASA Astrophysics Data System (ADS)

Ji, Se-Wan; Lee, Jaehak; Park, Jiyong; Nha, Hyunchul

2016-07-01

Quantum steering—a strong correlation to be verified even when one party or its measuring device is fully untrusted—not only provides a profound insight into quantum physics but also offers a crucial basis for practical applications. For continuous-variable (CV) systems, Gaussian states among others have been extensively studied, however, mostly confined to Gaussian measurements. While the fulfilment of Gaussian criterion is sufficient to detect CV steering, whether it is also necessary for Gaussian states is a question of fundamental importance in many contexts. This critically questions the validity of characterizations established only under Gaussian measurements like the quantification of steering and the monogamy relations. Here, we introduce a formalism based on local uncertainty relations of non-Gaussian measurements, which is shown to manifest quantum steering of some Gaussian states that Gaussian criterion fails to detect. To this aim, we look into Gaussian states of practical relevance, i.e. two-mode squeezed states under a lossy and an amplifying Gaussian channel. Our finding significantly modifies the characteristics of Gaussian-state steering so far established such as monogamy relations and one-way steering under Gaussian measurements, thus opening a new direction for critical studies beyond Gaussian regime.

Synthesis of CeO2 nanoparticles: Photocatalytic and antibacterial activities

NASA Astrophysics Data System (ADS)

Reddy Yadav, L. S.; Lingaraju, K.; Daruka Prasad, B.; Kavitha, C.; Banuprakash, G.; Nagaraju, G.

2017-05-01

We have successfully synthesized CeO2 nanoparticles (Nps) via the solution combustion method using sugarcane juice as a novel combustible fuel. The structural features, optical properties and morphology of the nanoparticles were characterized using XRD, FTIR, and Raman spectroscopy, UV-Vis, SEM and TEM. Structural characterization of the product shows cubic phase CeO2 . FTIR and Raman spectrum show characteristic peaks due to the presence of Ce-O vibration. SEM images show a porous structure and, from TEM images, the size of the nanoparticles were found to be ˜ 50 nm. The photocatalytic degradation of the methylene blue (MB) dye was examined using CeO2 Nps under solar irradiation as well as UV light irradiation and we studied the effect of p H, catalytic load and concentration on the degradation of the MB dye. Furthermore, the antibacterial properties of CeO2 Nps were investigated against Gram+ve and Gram- ve pathogenic bacterial strains using the agar well diffusion method.

Quadrat Data for Fermilab Prairie Plant Survey

Science.gov Websites

Quadrat Data 2012 Quadrat Data 2013 Quadrat Data None taken by volunteers in 2014 due to weather problems . 2015 Quadrat Data 2016 Quadrat Data None taken by volunteers in 2017 due to weather and other problems

Maximizing Your Grant Development: A Guide for CEOs.

ERIC Educational Resources Information Center

Snyder, Thomas

1993-01-01

Since most private and public sources of external funding generally expect increased effort and accountability, Chief Executive Officers (CEOs) at two-year colleges must inform faculty and staff that if they do not expend extra effort their college will not receive significant grants. The CEO must also work with the college's professional…

Non-Gaussian structure of B-mode polarization after delensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Namikawa, Toshiya; Nagata, Ryo, E-mail: namikawa@slac.stanford.edu, E-mail: rnagata@post.kek.jp

2015-10-01

The B-mode polarization of the cosmic microwave background on large scales has been considered as a probe of gravitational waves from the cosmic inflation. Ongoing and future experiments will, however, suffer from contamination due to the B-modes of non-primordial origins, one of which is the lensing induced B-mode polarization. Subtraction of the lensing B-modes, usually referred to as delensing, will be required for further improvement of detection sensitivity of the gravitational waves. In such experiments, knowledge of statistical properties of the B-modes after delensing is indispensable to likelihood analysis particularly because the lensing B-modes are known to be non-Gaussian. Inmore » this paper, we study non-Gaussian structure of the delensed B-modes on large scales, comparing it with that of the lensing B-modes. In particular, we investigate the power spectrum correlation matrix and the probability distribution function (PDF) of the power spectrum amplitude. Assuming an experiment in which the quadratic delensing is an almost optimal method, we find that delensing reduces correlations of the lensing B-mode power spectra between different multipoles, and that the PDF of the power spectrum amplitude is well described as a normal distribution function with a variance larger than that in the case of a Gaussian field. These features are well captured by an analytic model based on the 4th order Edgeworth expansion. As a consequence of the non-Gaussianity, the constraint on the tensor-to-scalar ratio after delensing is degraded within approximately a few percent, which depends on the multipole range included in the analysis.« less

Non-Gaussian structure of B-mode polarization after delensing

DOE PAGES

Namikawa, Toshiya; Nagata, Ryo

2015-10-01

The B-mode polarization of the cosmic microwave background on large scales has been considered as a probe of gravitational waves from the cosmic inflation. Ongoing and future experiments will, however, suffer from contamination due to the B-modes of non-primordial origins, one of which is the lensing induced B-mode polarization. Subtraction of the lensing B-modes, usually referred to as delensing, will be required for further improvement of detection sensitivity of the gravitational waves. In such experiments, knowledge of statistical properties of the B-modes after delensing is indispensable to likelihood analysis particularly because the lensing B-modes are known to be non-Gaussian. Inmore » this paper, we study non-Gaussian structure of the delensed B-modes on large scales, comparing it with that of the lensing B-modes. In particular, we investigate the power spectrum correlation matrix and the probability distribution function (PDF) of the power spectrum amplitude. Assuming an experiment in which the quadratic delensing is an almost optimal method, we find that delensing reduces correlations of the lensing B-mode power spectra between different multipoles, and that the PDF of the power spectrum amplitude is well described as a normal distribution function with a variance larger than that in the case of a Gaussian field. These features are well captured by an analytic model based on the 4th order Edgeworth expansion. Furthermore, as a consequence of the non-Gaussianity, the constraint on the tensor-to-scalar ratio after delensing is degraded within approximately a few percent, which depends on the multipole range included in the analysis.« less

Committee on Earth Observation Satellites (CEOS) Systems Engineering Office (SEO). Ocean Surface Topography (OST) Workshop, Ruedesheim an Rhein, Germany. [CEOS SEO Status Report

NASA Technical Reports Server (NTRS)

Killough, Brian D., Jr.

2008-01-01

The CEOS Systems Engineering Office will present a 2007 status report of the CEOS constellation process, present a new systems engineering framework, and analysis results from the GEO Societal Benefit Area (SBA) assessment and the OST constellation requirements assessment.

Language Choices of CEOs of Chinese Family Business in Sarawak, Malaysia

ERIC Educational Resources Information Center

Ting, Su-Hie

2017-01-01

The study investigated the language choices of Chief Executive Officers (CEOs) of Chinese family business and the factors guiding their choices. Interviews were conducted with 17 CEOs of family businesses located in Sarawak, some of whom are the sons and grandsons of the founder of the business. The results showed that all the CEOs can speak their…

Trustees as Reluctant Leaders: The Board/CEO Relationship.

ERIC Educational Resources Information Center

Sherman, Vaughn A.

Due to inertia within organizational cultures, relations between the boards and chief executive officers (CEO's) at community colleges tend to remain the same at each institution through time. The time has come to look at the separate roles of the CEO and trustee and then to decide how best at each institution to fashion a relationship between…

Quadratic time dependent Hamiltonians and separation of variables

NASA Astrophysics Data System (ADS)

Anzaldo-Meneses, A.

2017-06-01

Time dependent quantum problems defined by quadratic Hamiltonians are solved using canonical transformations. The Green's function is obtained and a comparison with the classical Hamilton-Jacobi method leads to important geometrical insights like exterior differential systems, Monge cones and time dependent Gaussian metrics. The Wei-Norman approach is applied using unitary transformations defined in terms of generators of the associated Lie groups, here the semi-direct product of the Heisenberg group and the symplectic group. A new explicit relation for the unitary transformations is given in terms of a finite product of elementary transformations. The sequential application of adequate sets of unitary transformations leads naturally to a new separation of variables method for time dependent Hamiltonians, which is shown to be related to the Inönü-Wigner contraction of Lie groups. The new method allows also a better understanding of interacting particles or coupled modes and opens an alternative way to analyze topological phases in driven systems.

The Facial Appearance of CEOs: Faces Signal Selection but Not Performance.

PubMed

Stoker, Janka I; Garretsen, Harry; Spreeuwers, Luuk J

2016-01-01

Research overwhelmingly shows that facial appearance predicts leader selection. However, the evidence on the relevance of faces for actual leader ability and consequently performance is inconclusive. By using a state-of-the-art, objective measure for face recognition, we test the predictive value of CEOs' faces for firm performance in a large sample of faces. We first compare the faces of Fortune500 CEOs with those of US citizens and professors. We find clear confirmation that CEOs do look different when compared to citizens or professors, replicating the finding that faces matter for selection. More importantly, we also find that faces of CEOs of top performing firms do not differ from other CEOs. Based on our advanced face recognition method, our results suggest that facial appearance matters for leader selection but that it does not do so for leader performance.

Implementing healthcare excellence: the vital role of the CEO in evidence-based design.

PubMed

Zimring, Craig; Augenbroe, Godfried L; Malone, Eileen B; Sadler, Blair L

2008-01-01

This paper explores the role of the chief executive officer (CEO) in evidence-based design (EBD), discussing the internal and external challenges that a CEO faces, such as demands for increased quality, safety, patient-and-family-centeredness, increased revenue, and reduced cost. Based on a series of interviews and case studies and the experience of the authors as researchers, consultants, and CEOs, this paper provides a model for EBD and recommends actions that a CEO can undertake to create an effective project over the life cycle of a building. TOPICAL HEADINGS: Evidence-Based Design: A Performance-Based Approach to Achieving Key Goals; Key Approaches to Executing Evidence-Based Design; Overcoming Barriers to Innovation: The CEO's Vital Role in Implementing Evidence-Based Design The CEO bears special responsibility for successful facility project implementation. Only the CEO possesses the responsibility and authority to articulate the strategy, vision, goals, and resource constraints that frame every project. With the support of their boards, CEOs set the stage for the transformation of an organization's culture and fuel clinical and business process reengineering by encouraging and, if necessary, forcing collaboration between the strong disciplinary and departmental divisions found in healthcare systems.

Event rate and reaction time performance in ADHD: Testing predictions from the state regulation deficit hypothesis using an ex-Gaussian model.

PubMed

Metin, Baris; Wiersema, Jan R; Verguts, Tom; Gasthuys, Roos; van Der Meere, Jacob J; Roeyers, Herbert; Sonuga-Barke, Edmund

2016-01-01

According to the state regulation deficit (SRD) account, ADHD is associated with a problem using effort to maintain an optimal activation state under demanding task settings such as very fast or very slow event rates. This leads to a prediction of disrupted performance at event rate extremes reflected in higher Gaussian response variability that is a putative marker of activation during motor preparation. In the current study, we tested this hypothesis using ex-Gaussian modeling, which distinguishes Gaussian from non-Gaussian variability. Twenty-five children with ADHD and 29 typically developing controls performed a simple Go/No-Go task under four different event-rate conditions. There was an accentuated quadratic relationship between event rate and Gaussian variability in the ADHD group compared to the controls. The children with ADHD had greater Gaussian variability at very fast and very slow event rates but not at moderate event rates. The results provide evidence for the SRD account of ADHD. However, given that this effect did not explain all group differences (some of which were independent of event rate) other cognitive and/or motivational processes are also likely implicated in ADHD performance deficits.

Three CEOs, Three Futures.

ERIC Educational Resources Information Center

Berry, John N., III

1998-01-01

Interviews with three CEOs--UMI (University Microfilms International), OCLC (Online Computer Library Center), and Gale Research--focus on outlooks for information and libraries. Discusses expanded educational Web services/courseware, library role in delivery, electronic dissertation publishing, digital data conversion, thesauri/indexing, union…

CEOs and CFOs express concern about materials management.

PubMed

Kowalski, J C

1998-05-01

In a recent survey, CEOs and CFOs expressed concern regarding the effectiveness of their materials management departments. Both groups of executives would like to see more improvement in their materials managers' supply expense reduction efforts and leadership skills. More than a third of CFOs are even considering outsourcing the materials management function. Both CEOs and CFOs did admit, however, they needed to learn more about materials management, and both groups of executives could lend their authority to materials management programs to ensure their success. CEOs and CFOs need to reach consensus regard materials management priorities, performance levels, and professional characteristics and desired skills. They also should hold materials managers accountable for operations they can and should be managing by using performance-based compensation.

Robust Finite-Dimensional LQG (Linear Quadric Gaussian)-Based Controllers for a Class of Distributed Parameter Systems.

DTIC Science & Technology

1988-06-01

abilities when I lost confidence. Without her help I would not have completed the program. Next, I wish to thank Dr. Peter Maybeck, my research ...being not only a resource for my research . but also for being a friend who listened when I needed a shoulder to cry on. Finally, I wish to give thanks...considered in this research are assumed to be linear quadratic Gaussian (LQG) based controllers. This research first uses a direct approach to

Hexagonal CeO2 nanostructures: an efficient electrode material for supercapacitors.

PubMed

Maheswari, Nallappan; Muralidharan, Gopalan

2016-09-28

Cerium oxide (CeO2) has emerged as a new and promising pseudocapacitive material due to its prominent valance states and extensive applications in various fields. In the present study, hexagonal CeO2 nanostructures have been prepared via the hydrothermal method employing cationic surfactant cetyl trimethyl ammonium bromide (CTAB). CTAB ensures a slow rate of hydrolysis to form small sized CeO2 nanostructures. The role of calcination temperature on the morphological, structural, electrochemical properties and cyclic stability has been assessed for supercapacitor applications. The mesoscopic hexagonal architecture endows the CeO2 with not only a higher specific capacity, but also with an excellent rate capability and cyclability. When the charge/discharge current density is increased from 2 to 10 A g(-1) the reversible charge capacity decreased from 927 F g(-1) to 475 F g(-1) while 100% capacity retention at a high current density of 20 A g(-1) even after 1500 cycles could be achieved. Furthermore, the asymmetric supercapacitor based on CeO2 exhibited a significantly higher energy density of 45.6 W h kg(-1) at a power density of 187.5 W kg(-1) with good cyclic stability. The electrochemical richness of the CeO2 nanostructure makes it a suitable electrode material for supercapacitor applications.

Toxicity of CeO2 nanoparticles - the effect of nanoparticle properties.

PubMed

Leung, Yu Hang; Yung, Mana M N; Ng, Alan M C; Ma, Angel P Y; Wong, Stella W Y; Chan, Charis M N; Ng, Yip Hang; Djurišić, Aleksandra B; Guo, Muyao; Wong, Mabel Ting; Leung, Frederick C C; Chan, Wai Kin; Leung, Kenneth M Y; Lee, Hung Kay

2015-04-01

Conflicting reports on the toxicity of CeO2 nanomaterials have been published in recent years, with some studies finding CeO2 nanoparticles to be toxic, while others found it to have protective effects against oxidative stress. To investigate the possible reasons for this, we have performed a comprehensive study on the physical and chemical properties of nanosized CeO2 from three different suppliers as well as CeO2 synthesized by us, and tested their toxicity. For toxicity tests, we have studied the effects of CeO2 nanoparticles on a Gram-negative bacterium Escherichia coli in the dark, under ambient and UV illuminations. We have also performed toxicity tests on the marine diatom Skeletonema costatum under ambient and UV illuminations. We found that the CeO2 nanoparticle samples exhibited significantly different toxicity, which could likely be attributed to the differences in interactions with cells, and possibly to differences in nanoparticle compositions. Our results also suggest that toxicity tests on bacteria may not be suitable for predicting the ecotoxicity of nanomaterials. The relationship between the toxicity and physicochemical properties of the nanoparticles is explicitly discussed in the light of the current results. Copyright © 2015 Elsevier B.V. All rights reserved.

Hospital CEOs Need Health IT Knowledge and Trust in CIOs: Insights from a Qualitative Study.

PubMed

Thye, Johannes; Hübner, Ursula; Weiß, Jan-Patrick; Teuteberg, Frank; Hüsers, Jens; Liebe, Jan-David; Babitsch, Birgit

2018-01-01

IT is getting an increasing importance in hospitals. In this context, major IT decisions are often made by CEOs who are not necessarily IT experts. Therefore, this study aimed at a) exploring different types of IT decision makers at CEO level, b) identifying hypotheses if trust exists between these different types of CEOs and their CIOs and c) building hypotheses on potential consequences regarding risk taking and innovation. To this end, 14 qualitative interviews with German hospital CEOs were conducted to explore the research questions. The study revealed three major types: IT savvy CEOs, IT enthusiastic CEOs and IT indifferent CEOs. Depending on these types, their relationship with the CIO varied in terms of trust and common language. In case of IT indifferent CEOs, a potential vicious circle of lack of IT knowledge, missing trust, low willingness to take risks and low innovation power could be identified. In order to break of this circle, CEOs seem to need more IT knowledge and/or greater trust in their CIO.

The Impact of Taxes on Competition for CEOs.

PubMed

Krenn, Peter

2017-07-03

This paper contributes to the question of how taxation of corporate profits and wages affects competition among firms for highly skilled human resources such as CEOs. Use of a theoretical model shows that wage taxes can have a substantial impact on the outcome of such a competition if marginal tax rates are different as in an international labor market. Further, the paper shows that increasing the wage tax rate unilaterally can have an ambiguous effect on observed gross compensation levels. However, in a local labor market for CEOs, observed gross fixed salaries should decline in the wage tax rate. Tax effects in a market for CEOs is a particularly interesting topic because recent developments with respect to compensation practices of top-level managers have opened a public debate about the use of instruments for regulating compensation of those managers. Furthermore, many countries around the world use tax incentives in order to facilitate immigration of highly skilled human resources. The investigation follows an analytical economics-based approach by extending an LEN model with elements of competition for scarce human resources and income taxation. It investigates the impact of differential taxation on the competition between two firms for the exclusive service of a unique, highly skilled CEO.

The Impact of Taxes on Competition for CEOs

PubMed Central

Krenn, Peter

2017-01-01

Abstract This paper contributes to the question of how taxation of corporate profits and wages affects competition among firms for highly skilled human resources such as CEOs. Use of a theoretical model shows that wage taxes can have a substantial impact on the outcome of such a competition if marginal tax rates are different as in an international labor market. Further, the paper shows that increasing the wage tax rate unilaterally can have an ambiguous effect on observed gross compensation levels. However, in a local labor market for CEOs, observed gross fixed salaries should decline in the wage tax rate. Tax effects in a market for CEOs is a particularly interesting topic because recent developments with respect to compensation practices of top-level managers have opened a public debate about the use of instruments for regulating compensation of those managers. Furthermore, many countries around the world use tax incentives in order to facilitate immigration of highly skilled human resources. The investigation follows an analytical economics-based approach by extending an LEN model with elements of competition for scarce human resources and income taxation. It investigates the impact of differential taxation on the competition between two firms for the exclusive service of a unique, highly skilled CEO. PMID:29097851

CEO- CNE relationships: building an evidence-base of chief nursing executive replacement costs.

PubMed

Sredl, Darlene; Peng, Niang-Huei

2010-06-03

Explore professional relationships between Chief Nurse Executives (CNEs) and Chief Executive Officers (CEOs); CNE ethnic diversity; and CNE replacement costs. Theoretical frameworks - Marilyn Ray's Theory of Bureaucratic Caring, and Turkel's Theory of Relational Complexity espousing economic as well as caring variables. Exploratory mixed-method descriptive design using CNE mailed survey. CNE- cited opportunities for maintaining a positive relationship with the CEO: respect for CEO; goal- sharing (r=.782, p<0.01); having a strong relationship (r= .718, p<0.01); co-problem-solving (r=.437, p<0.01); having an interesting job (r=.406, p<0.01); having similar interests with CEO (r= .346, p<0.01); CEO and CNE maintaining specific roles (r= .261, p<0.05); satisfaction with CNE income (r=.251, p<0.05); willingness to improve relationship with CEO (r=.254, p<0.05). CNE positions demonstrated an ethnic diversity factor of 0.03%. CNE replacement costs to healthcare facilities were over 1.5 million dollars. CNE/CEO relationships have identified cohesive factors that may contribute to CNE longevity in position; an ethically diverse CNE deficit exists; and, CNE turnover and vacancy rates impact an organization's financial health and quality of care.

CEO summit. The leadership experience--roundtable discussion.

PubMed

Corley, B; Crawford, M; Norling, R; Burgin, B; Ackerman, F K; Wallace, S

1995-02-05

All across the country, hospitals, physicians and insurers are sizing each other up as potential strategic partners. But there's much ground to be covered before a final agreement is reached, and not every decision is based on facts and figures. Sometimes it's the personal interaction between CEOs that makes the deal happen--or not. McManis Associates and Hospitals & Health Networks brought together a roundtable of CEOs to talk about the ups and downs and the ins and outs of the leadership experience. Following is a series of first-person accounts by roundtable participants.

Distilling Gaussian states with Gaussian operations is impossible.

PubMed

Eisert, J; Scheel, S; Plenio, M B

2002-09-23

We show that no distillation protocol for Gaussian quantum states exists that relies on (i) arbitrary local unitary operations that preserve the Gaussian character of the state and (ii) homodyne detection together with classical communication and postprocessing by means of local Gaussian unitary operations on two symmetric identically prepared copies. This is in contrast to the finite-dimensional case, where entanglement can be distilled in an iterative protocol using two copies at a time. The ramifications for the distribution of Gaussian states over large distances will be outlined. We also comment on the generality of the approach and sketch the most general form of a Gaussian local operation with classical communication in a bipartite setting.

Morphology of size-selected Ptn clusters on CeO2(111)

NASA Astrophysics Data System (ADS)

Shahed, Syed Mohammad Fakruddin; Beniya, Atsushi; Hirata, Hirohito; Watanabe, Yoshihide

2018-03-01

Supported Pt catalysts and ceria are well known for their application in automotive exhaust catalysts. Size-selected Pt clusters supported on a CeO2(111) surface exhibit distinct physical and chemical properties. We investigated the morphology of the size-selected Ptn (n = 5-13) clusters on a CeO2(111) surface using scanning tunneling microscopy at room temperature. Ptn clusters prefer a two-dimensional morphology for n = 5 and a three-dimensional (3D) morphology for n ≥ 6. We further observed the preference for a 3D tri-layer structure when n ≥ 10. For each cluster size, we quantitatively estimated the relative fraction of the clusters for each type of morphology. Size-dependent morphology of the Ptn clusters on the CeO2(111) surface was attributed to the Pt-Pt interaction in the cluster and the Pt-O interaction between the cluster and CeO2(111) surface. The results obtained herein provide a clear understanding of the size-dependent morphology of the Ptn clusters on a CeO2(111) surface.

Morphology of size-selected Ptn clusters on CeO2(111).

PubMed

Shahed, Syed Mohammad Fakruddin; Beniya, Atsushi; Hirata, Hirohito; Watanabe, Yoshihide

2018-03-21

Supported Pt catalysts and ceria are well known for their application in automotive exhaust catalysts. Size-selected Pt clusters supported on a CeO 2 (111) surface exhibit distinct physical and chemical properties. We investigated the morphology of the size-selected Pt n (n = 5-13) clusters on a CeO 2 (111) surface using scanning tunneling microscopy at room temperature. Pt n clusters prefer a two-dimensional morphology for n = 5 and a three-dimensional (3D) morphology for n ≥ 6. We further observed the preference for a 3D tri-layer structure when n ≥ 10. For each cluster size, we quantitatively estimated the relative fraction of the clusters for each type of morphology. Size-dependent morphology of the Pt n clusters on the CeO 2 (111) surface was attributed to the Pt-Pt interaction in the cluster and the Pt-O interaction between the cluster and CeO 2 (111) surface. The results obtained herein provide a clear understanding of the size-dependent morphology of the Pt n clusters on a CeO 2 (111) surface.

Normal form decomposition for Gaussian-to-Gaussian superoperators

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Palma, Giacomo; INFN, Pisa; Mari, Andrea

2015-05-15

In this paper, we explore the set of linear maps sending the set of quantum Gaussian states into itself. These maps are in general not positive, a feature which can be exploited as a test to check whether a given quantum state belongs to the convex hull of Gaussian states (if one of the considered maps sends it into a non-positive operator, the above state is certified not to belong to the set). Generalizing a result known to be valid under the assumption of complete positivity, we provide a characterization of these Gaussian-to-Gaussian (not necessarily positive) superoperators in terms ofmore » their action on the characteristic function of the inputs. For the special case of one-mode mappings, we also show that any Gaussian-to-Gaussian superoperator can be expressed as a concatenation of a phase-space dilatation, followed by the action of a completely positive Gaussian channel, possibly composed with a transposition. While a similar decomposition is shown to fail in the multi-mode scenario, we prove that it still holds at least under the further hypothesis of homogeneous action on the covariance matrix.« less

The CEO hits the road (and other sales tales).

PubMed

Mackay, H B

1990-01-01

Kenneth Macke, CEO of Dayton-Hudson, the soft goods and discount store chain, often spends weekends prowling his own and competitors' stores, observing. Edwin Artzt, CEO of Procter & Gamble, once interrupted a global marketing jaunt to work with a division on its promotion plans. These are CEOs in the trenches, a place where they ought to spend a certain amount of their time so that they can learn how the business is going. "A desk is a dangerous place from which to view the world," says John le Carré, as quoted approvingly by the author. Mackay asserts that time spent on the road with the sales force is especially valuable. You will learn: Whether all the sales team knows its prospects and sets reasonable expectations. How much the salespeople know about the product, particularly in ways that differentiate it from the competition. Whether the sellers keep abreast of changes in customers' businesses. If the salespeople feel they have a stake in the business. As a rookie envelope salesman, Mackay was taken in tow by a veteran and shown the value of learning the competition's local customer base intimately. Later, as the CEO with a junior salesperson in tow, he demonstrated the value of learning not only the competition's moves but also the customers'. To close sales, salespeople and the CEO have to look over their customers' shoulders as well as their competitors'.

Quadratic spline subroutine package

USGS Publications Warehouse

Rasmussen, Lowell A.

1982-01-01

A continuous piecewise quadratic function with continuous first derivative is devised for approximating a single-valued, but unknown, function represented by a set of discrete points. The quadratic is proposed as a treatment intermediate between using the angular (but reliable, easily constructed and manipulated) piecewise linear function and using the smoother (but occasionally erratic) cubic spline. Neither iteration nor the solution of a system of simultaneous equations is necessary to determining the coefficients. Several properties of the quadratic function are given. A set of five short FORTRAN subroutines is provided for generating the coefficients (QSC), finding function value and derivatives (QSY), integrating (QSI), finding extrema (QSE), and computing arc length and the curvature-squared integral (QSK). (USGS)

Quadratic Polynomial Regression using Serial Observation Processing:Implementation within DART

NASA Astrophysics Data System (ADS)

Hodyss, D.; Anderson, J. L.; Collins, N.; Campbell, W. F.; Reinecke, P. A.

2017-12-01

Many Ensemble-Based Kalman ltering (EBKF) algorithms process the observations serially. Serial observation processing views the data assimilation process as an iterative sequence of scalar update equations. What is useful about this data assimilation algorithm is that it has very low memory requirements and does not need complex methods to perform the typical high-dimensional inverse calculation of many other algorithms. Recently, the push has been towards the prediction, and therefore the assimilation of observations, for regions and phenomena for which high-resolution is required and/or highly nonlinear physical processes are operating. For these situations, a basic hypothesis is that the use of the EBKF is sub-optimal and performance gains could be achieved by accounting for aspects of the non-Gaussianty. To this end, we develop here a new component of the Data Assimilation Research Testbed [DART] to allow for a wide-variety of users to test this hypothesis. This new version of DART allows one to run several variants of the EBKF as well as several variants of the quadratic polynomial lter using the same forecast model and observations. Dierences between the results of the two systems will then highlight the degree of non-Gaussianity in the system being examined. We will illustrate in this work the differences between the performance of linear versus quadratic polynomial regression in a hierarchy of models from Lorenz-63 to a simple general circulation model.

It's More than Just Talk: Patterns of CEO Impromptu Communication

ERIC Educational Resources Information Center

Grant, Anett D.; Taylor, Amanda

2015-01-01

This article investigates whether CEOs actually demonstrate the communication strengths and weaknesses they think they have. Videotaped interviews with CEOs in the initial stage of executive coaching were analyzed to identify categories of communication strength and weakness: delivery, content, audience, and character. Next, the interviews and…

CEOS SEO and GISS Meeting

NASA Technical Reports Server (NTRS)

Killough, Brian; Stover, Shelley

2008-01-01

The Committee on Earth Observation Satellites (CEOS) provides a brief to the Goddard Institute for Space Studies (GISS) regarding the CEOS Systems Engineering Office (SEO) and current work on climate requirements and analysis. A "system framework" is provided for the Global Earth Observation System of Systems (GEOSS). SEO climate-related tasks are outlined including the assessment of essential climate variable (ECV) parameters, use of the "systems framework" to determine relevant informational products and science models and the performance of assessments and gap analyses of measurements and missions for each ECV. Climate requirements, including instruments and missions, measurements, knowledge and models, and decision makers, are also outlined. These requirements would establish traceability from instruments to products and services allowing for benefit evaluation of instruments and measurements. Additionally, traceable climate requirements would provide a better understanding of global climate models.

Gaussian vs non-Gaussian turbulence: impact on wind turbine loads

NASA Astrophysics Data System (ADS)

Berg, J.; Mann, J.; Natarajan, A.; Patton, E. G.

2014-12-01

In wind energy applications the turbulent velocity field of the Atmospheric Boundary Layer (ABL) is often characterised by Gaussian probability density functions. When estimating the dynamical loads on wind turbines this has been the rule more than anything else. From numerous studies in the laboratory, in Direct Numerical Simulations, and from in-situ measurements of the ABL we know, however, that turbulence is not purely Gaussian: the smallest and fastest scales often exhibit extreme behaviour characterised by strong non-Gaussian statistics. In this contribution we want to investigate whether these non-Gaussian effects are important when determining wind turbine loads, and hence of utmost importance to the design criteria and lifetime of a wind turbine. We devise a method based on Principal Orthogonal Decomposition where non-Gaussian velocity fields generated by high-resolution pseudo-spectral Large-Eddy Simulation (LES) of the ABL are transformed so that they maintain the exact same second-order statistics including variations of the statistics with height, but are otherwise Gaussian. In that way we can investigate in isolation the question whether it is important for wind turbine loads to include non-Gaussian properties of atmospheric turbulence. As an illustration the Figure show both a non-Gaussian velocity field (left) from our LES, and its transformed Gaussian Counterpart (right). Whereas the horizontal velocity components (top) look close to identical, the vertical components (bottom) are not: the non-Gaussian case is much more fluid-like (like in a sketch by Michelangelo). The question is then: Does the wind turbine see this? Using the load simulation software HAWC2 with both the non-Gaussian and newly constructed Gaussian fields, respectively, we show that the Fatigue loads and most of the Extreme loads are unaltered when using non-Gaussian velocity fields. The turbine thus acts like a low-pass filter which average out the non-Gaussian behaviour on time

The Facial Appearance of CEOs: Faces Signal Selection but Not Performance

PubMed Central

Garretsen, Harry; Spreeuwers, Luuk J.

2016-01-01

Research overwhelmingly shows that facial appearance predicts leader selection. However, the evidence on the relevance of faces for actual leader ability and consequently performance is inconclusive. By using a state-of-the-art, objective measure for face recognition, we test the predictive value of CEOs’ faces for firm performance in a large sample of faces. We first compare the faces of Fortune500 CEOs with those of US citizens and professors. We find clear confirmation that CEOs do look different when compared to citizens or professors, replicating the finding that faces matter for selection. More importantly, we also find that faces of CEOs of top performing firms do not differ from other CEOs. Based on our advanced face recognition method, our results suggest that facial appearance matters for leader selection but that it does not do so for leader performance. PMID:27462986

The Principal as CEO

ERIC Educational Resources Information Center

Hollar, Charlie

2004-01-01

They may never grace the pages of The Wall Street Journal or Fortune magazine, but they might possibly be the most important CEOs in our country. They are elementary school principals. Each of them typically serves the learning needs of 350-400 clients (students) while overseeing a multimillion-dollar facility staffed by 20-25 teachers and 10-15…

Not-for-profit hospital CEO performance and pay: some evidence from Connecticut.

PubMed

Kramer, Jeffrey; Santerre, Rexford E

2010-01-01

This paper uses observations from a panel data set of 35 chief executive officers (CEOs) from 29 not-for-profit hospitals in Connecticut over the period 1998 to 2006 to investigate the relationship between CEO performance and pay. Both economic and charity performance measures are specified in the empirical model. The multiple regression results reveal that not-for-profit hospital CEOs, at least in Connecticut, are driven at the margin to increase the occupancy rate of privately insured patients at the expense of uncompensated care and public-pay patients. This type of behavior on the part of not-for-profit hospital CEOs calls into question the desirability of allowing these hospitals a tax exemption on earned income, property, and purchases.

The Factorability of Quadratics: Motivation for More Techniques

ERIC Educational Resources Information Center

Bosse, Michael J.; Nandakumar, N. R.

2005-01-01

Typically, secondary and college algebra students attempt to utilize either completing the square or the quadratic formula as techniques to solve a quadratic equation only after frustration with factoring has arisen. While both completing the square and the quadratic formula are techniques which can determine solutions for all quadratic equations,…

Mechanical, lattice dynamical and electronic properties of CeO2 at high pressure: First-principles studies

NASA Astrophysics Data System (ADS)

Li, Mei; Jia, Huiling; Li, Xueyan; Liu, Xuejie

2016-01-01

The elastic constants (Cij), bulk modulus (B), shear modulus (G) and elastic modulus (E) of cubic fluorite CeO2 under high pressure have been studied using the plane-wave pseudopotential method based on density functional theory. The calculated results show that the mechanical properties (Cij, B, G and E) of CeO2 increase with increasing pressure, and the phase transition of CeO2 occurs beyond the pressure of 130 GPa. From the calculated phonon spectrum using Parlinsk-Li-Kawasoe method, we found that CeO2 appears imaginary frequency at 140 GPa, which indicates phase transition. The energy band, density of states and charge density of CeO2 under high pressure are calculated using GGA+U method. It is found that the high pressure makes the electron delocalization and Ce-O covalent bonding enhanced. As pressure increases, the band gap between O2p and Ce4f states near the Fermi level increases, and CeO2 nonmetallic nature promotes. The present research results in a better understanding of how CeO2 responds to compression.

Hospital CEOs, CFOs, and nurse executives: opportunities for a new alliance.

PubMed

Dwore, R B; Murray, B P; Fosbinder, D; Parsons, R P; Smith, P; Dalley, K; Vorderer, L; Gustafson, G

1998-01-01

This article examines the involvement of Utah acute care hospital nurse executives (NEs) in financial management roles. The authors surveyed NEs and their career supporters and hinderers. Findings suggest that NFs: 1. lack financial management skills, support, involvement, and satisfaction; 2. recognize financial management's importance and desire to improve performance; and 3. consider chief executive officers (CEOs) as their major supporters and chief financial officers (CFOs) their major hinderers in financial management. These "supporters" and "hinderers" of NEs showed consensus regarding the primacy of NEs' leadership and patient advocacy roles. These findings contrast with major professional association policy directives and expert opinions that advocate expanded financial management roles for NEs that will enable them to fully realize their executive potential. CEOs are positioned to establish norms that balance the traditional leadership-patient advocacy roles of NEs with newer financial management roles. CEOs can offer NEs and CFOs opportunities to improve NEs' financial management participation and performance. CEOs can provide empowerment and encourage CFOs to offer NEs "power tools" (for example, information, expertise, resources, and support). The three groups, however, must negotiate reasonable expectations for NEs in financial management and adequate preparation for these consequent responsibilities. Together, CEOs, CFOs, and NEs can successfully take hospitals into the future by leading them in ongoing learning and change.

New Hampshire critical access hospitals: CEOs' report on ethical challenges.

PubMed

Nelson, William; Rosenberg, Marie-Claire; Weiss, Julie; Goodrich, Martha

2009-01-01

Research into the importance of organizational healthcare ethics has increasingly appeared in healthcare publications. However, to date, few published studies have examined ethical issues from the perspective of healthcare executives, and no empirical study has addressed organizational ethics with an explicit focus on rural hospitals. For our study, we sought to identify the frequency of ethical conflicts occurring within 12 general categories (domains) of administrative activities. Also, we wanted to determine what ethics resources are currently available and whether additional resources would be helpful. We conducted a structured telephone interview of all 13 chief executive officers (CEOs) of critical access hospitals in New Hampshire. All the CEOs in the study indicated that they encountered ethical conflicts. On average, the three most frequently noted domains were organizational-professional staff relations, reimbursement, and clinical care. All CEOs indicated they would like to have additional ethics resources to address these conflicts. This study verified that CEOs encounter a broad spectrum of ethical conflicts and need additional ethics resources to address them. Because this study used a small sample of CEOs and represented only one New England state, further ethics-related research in rural healthcare facilities is warranted. Follow-up study would allow for (1) a higher level of generalization of the findings, (2) clarity regarding specific ethical dilemmas that rural healthcare executives encounter, and (3) an assessment of ethics resources and training that healthcare executives need to address the ethical conflicts.

Students' Understanding of Quadratic Equations

ERIC Educational Resources Information Center

López, Jonathan; Robles, Izraim; Martínez-Planell, Rafael

2016-01-01

Action-Process-Object-Schema theory (APOS) was applied to study student understanding of quadratic equations in one variable. This required proposing a detailed conjecture (called a genetic decomposition) of mental constructions students may do to understand quadratic equations. The genetic decomposition which was proposed can contribute to help…

Committee on Earth Observation Satellites (CEOS) perspectives about the GEO Supersite initiative

NASA Astrophysics Data System (ADS)

Lengert, Wolfgang; Zoffoli, Simona; Giguere, Christine; Hoffmann, Joern; Lindsay, Francis; Seguin, Guy

2014-05-01

This presentation is outlining the effort of the Committee on Earth Observation Satellites (CEOS) using its global collaboration structure to support implementing the GEO priority action DI-01 Informing Risk Management and Disaster Reduction addressing the component: C2 Geohazards Monitoring, Alert, and Risk Assessment. A CEOS Supersites Coordination Team (SCT) has been established in order to make best use of the CEOS global satellite resources. For this, the CEOS SCT has taken a holistic view on the science data needs and availability of resources, considering the constraints and exploitation potentials of synergies. It is interfacing with the Supersites Science Advisory Group and the Principle Investigators to analyze how the satellite data associated with seismic and Global Navigation Satellite System (GNSS) data can support national authorities and policy makers in risk assessment and the development of mitigation strategies. CEOS SCT aims to support the establishment of a fully integrated approach to geohazards monitoring, based on collaboration among existing networks and international initiatives, using new instrumentation such as in-situ sensors, and aggregating space (radar, optical imagery) and ground-based (subsurface) observations. The three Supersites projects which are funded under the EC FP7 action, namely (i) FUTUREVOLC: A European volcanological supersite in Iceland: a monitoring system and network for the future Geohazards Monitoring, Alert, and Risk Assessment, (ii) MARsite: New Directions in Seismic Hazard assessment through Focused Earth Observation in the Marmara Supersite, (iii) MED-SUV: MEDiterranean Volcanoes and related seismic risks, have been examined as a vehicle to fulfill these ambitious objectives. FUTUREVOLC has already been granted CEOS support. This presentation will outline CEOS agreed process and criteria applied by the Supersites Coordination Team (SCT), for selecting these Supersites in the context of the GSNL initiative, as

Gender Differences in Hospital CEO Compensation: A National Investigation of Not-for-Profit Hospitals.

PubMed

Song, Paula H; Lee, Shoou-Yih Daniel; Toth, Matthew; Singh, Simone R; Young, Gary J

2018-01-01

Gender pay equity is a desirable social value and an important strategy to fill every organizational stratum with gender-diverse talent to fulfill an organization's goals and mission. This study used national, large-sample data to examine gender difference in CEO compensation among not-for-profit hospitals. Results showed the average unadjusted annual compensation for female CEOs in 2009 was $425,085 compared with $581,121 for male CEOs. With few exceptions, the difference existed across all types of not-for-profit hospitals. After controlling for hospital- and area-level characteristics, female CEOs of not-for-profit hospitals earned 22.6% less than male CEOs of not-for-profit hospitals. This translates into an earnings differential of $132,652 associated with gender. Explanations and implications of the results are discussed.

Exact solutions to quadratic gravity

NASA Astrophysics Data System (ADS)

Pravda, V.; Pravdová, A.; Podolský, J.; Švarc, R.

2017-04-01

Since all Einstein spacetimes are vacuum solutions to quadratic gravity in four dimensions, in this paper we study various aspects of non-Einstein vacuum solutions to this theory. Most such known solutions are of traceless Ricci and Petrov type N with a constant Ricci scalar. Thus we assume the Ricci scalar to be constant which leads to a substantial simplification of the field equations. We prove that a vacuum solution to quadratic gravity with traceless Ricci tensor of type N and aligned Weyl tensor of any Petrov type is necessarily a Kundt spacetime. This will considerably simplify the search for new non-Einstein solutions. Similarly, a vacuum solution to quadratic gravity with traceless Ricci type III and aligned Weyl tensor of Petrov type II or more special is again necessarily a Kundt spacetime. Then we study the general role of conformal transformations in constructing vacuum solutions to quadratic gravity. We find that such solutions can be obtained by solving one nonlinear partial differential equation for a conformal factor on any Einstein spacetime or, more generally, on any background with vanishing Bach tensor. In particular, we show that all geometries conformal to Kundt are either Kundt or Robinson-Trautman, and we provide some explicit Kundt and Robinson-Trautman solutions to quadratic gravity by solving the above mentioned equation on certain Kundt backgrounds.

SO2 Adsorption on CeO2(100) and CeO2(111)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mullins, David R.

2016-09-13

The adsorption and reaction of sulfur dioxide, SO2, was studied on oxidized and reduced CeOX(100) and compared to previous results on CeOX(111). SO2 adsorbs on oxidized CeO2(100) as sulfite, SO32-, at 200 K and sulfite is the only adsorbate observed on the surface at any temperature. The sulfite desorbs monotonically from 200 to 700 K. The adsorption and desorption of SO2 does not result in any change in the Ce4+ oxidation state. SO2 also adsorbs as sulfite on reduced CeO1.7(100) at 200 K. There is also a small amount of elemental sulfur, S0, formed. As the sample is heated themore » sulfite decomposes into sulfide, S2-. Roughly 25 % of the adsorbed S either desorbs or diffuses into the bulk of the reduced ceria. The decomposition, and resulting formation of S2- and O2-, re-oxidize some of the Ce3+ to Ce4+. Unlike what has been observed following the adsorption and reaction of many other molecules, the adsorption and reaction of SO2 is virtually identical on CeOX(100) and CeOX(111).« less

Enhanced infrared emissivity of CeO2 coatings by La doping

NASA Astrophysics Data System (ADS)

Huang, Jianping; Fan, Chenglei; Song, Guangping; Li, Yibin; He, Xiaodong; Zhang, Xinjiang; Sun, Yue; Du, Shanyi; Zhao, Yijie

2013-09-01

Pure CeO2 and La doped CeO2 (LDC) coatings were prepared on nickel-based substrates by electron beam physical vapor deposition at 1173 K. The infrared emissivity in 2.5-25 μm of LDC coatings was enhanced with the increase of La concentration at high temperature 873-1273 K. Compared to the undoped CeO2 coating, the infrared emissivity of 16.7% LDC coating increases by 55%, and reaches up to 0.9 at 873 K. The enhancement of doped coatings’ emissivity is attributed to the increasing lattice absorption and free-carrier absorption. The high emissivity LDC coatings show a promising potential in high temperature application.

Orthogonality preserving infinite dimensional quadratic stochastic operators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akın, Hasan; Mukhamedov, Farrukh

In the present paper, we consider a notion of orthogonal preserving nonlinear operators. We introduce π-Volterra quadratic operators finite and infinite dimensional settings. It is proved that any orthogonal preserving quadratic operator on finite dimensional simplex is π-Volterra quadratic operator. In infinite dimensional setting, we describe all π-Volterra operators in terms orthogonal preserving operators.

A facile synthesis of high quality nanostructured CeO2 and Gd2O3-doped CeO2 solid electrolytes for improved electrochemical performance.

PubMed

Kuo, Yu-Lin; Su, Yu-Ming; Chou, Hung-Lung

2015-06-07

This study describes the use of a composite nitrate salt solution as a precursor to synthesize CeO2 and Gd2O3-doped CeO2 (GDC) nanoparticles (NPs) using an atmospheric pressure plasma jet (APPJ). The microstructures of CeO2 and GDC NPs were found to be cubical and spherical shaped nanocrystallites with average particle sizes of 10.5 and 6.7 nm, respectively. Reactive oxygen species, detected by optical emission spectroscopy (OES), are believed to be the major oxidative agents for the formation of oxide materials in the APPJ process. Based on the material characterization and OES observations, the study effectively demonstrated the feasibility of preparing well-crystallized GDC NPs by the APPJ system as well as the gas-to-particle mechanism. Notably, the Bader charge of CeO2 and Ce0.9Gd0.1O2 characterized by density function theory (DFT) simulation and AC impedance measurements shows that Gd helps in increasing the charge on Ce0.9Gd0.1O2 NPs, thus improving their conductivity and making them candidate materials for electrolytes in solid oxide fuel cells.

Gaussian entanglement revisited

NASA Astrophysics Data System (ADS)

Lami, Ludovico; Serafini, Alessio; Adesso, Gerardo

2018-02-01

We present a novel approach to the separability problem for Gaussian quantum states of bosonic continuous variable systems. We derive a simplified necessary and sufficient separability criterion for arbitrary Gaussian states of m versus n modes, which relies on convex optimisation over marginal covariance matrices on one subsystem only. We further revisit the currently known results stating the equivalence between separability and positive partial transposition (PPT) for specific classes of Gaussian states. Using techniques based on matrix analysis, such as Schur complements and matrix means, we then provide a unified treatment and compact proofs of all these results. In particular, we recover the PPT-separability equivalence for: (i) Gaussian states of 1 versus n modes; and (ii) isotropic Gaussian states. In passing, we also retrieve (iii) the recently established equivalence between separability of a Gaussian state and and its complete Gaussian extendability. Our techniques are then applied to progress beyond the state of the art. We prove that: (iv) Gaussian states that are invariant under partial transposition are necessarily separable; (v) the PPT criterion is necessary and sufficient for separability for Gaussian states of m versus n modes that are symmetric under the exchange of any two modes belonging to one of the parties; and (vi) Gaussian states which remain PPT under passive optical operations can not be entangled by them either. This is not a foregone conclusion per se (since Gaussian bound entangled states do exist) and settles a question that had been left unanswered in the existing literature on the subject. This paper, enjoyable by both the quantum optics and the matrix analysis communities, overall delivers technical and conceptual advances which are likely to be useful for further applications in continuous variable quantum information theory, beyond the separability problem.

Characterization and synergetic antibacterial properties of ZnO and CeO2 supported by halloysite

NASA Astrophysics Data System (ADS)

Shu, Zhan; Zhang, Yi; Ouyang, Jing; Yang, Huaming

2017-10-01

A novel antibacterial nanocomposite, CeO2-ZnO/HNTs was prepared by a homogeneous co-precipitation method in ethanol solution. ZnO and CeO2 nanoparticles with sizes of approximately 8 and 4 nm, respectively, were dispersively precipitated onto the surface of halloysite nanotubes (HNTs). HNTs served as a template for reducing the agglomeration of ZnO nanoparticles and improving the interface reactions between the nanocomposite and bacteria cells. CeO2 nanoparticles were introduced to suppress the recombination of electron-hole pairs, and narrow the energy gap of ZnO nanoparticles. The synergistic effects of ZnO, CeO2 nanoparticles and HNTs led to the superior antibacterial activity of the CeO2-ZnO/HNTs nanocomposite against gram-negative Escherichia coli.

Quantum key distillation from Gaussian states by Gaussian operations.

PubMed

Navascués, M; Bae, J; Cirac, J I; Lewestein, M; Sanpera, A; Acín, A

2005-01-14

We study the secrecy properties of Gaussian states under Gaussian operations. Although such operations are useless for quantum distillation, we prove that it is possible to distill a secret key secure against any attack from sufficiently entangled Gaussian states with nonpositive partial transposition. Moreover, all such states allow for key distillation, when Eve is assumed to perform finite-size coherent attacks before the reconciliation process.

Morphology, structure and optical properties of hydrothermally synthesized CeO2/CdS nanocomposites

NASA Astrophysics Data System (ADS)

Mohanty, Biswajyoti; Nayak, J.

2018-04-01

CeO2/CdS nanocomposites were synthesized using a two-step hydrothermal technique. The effects of precursor concentration on the optical and structural properties of the CeO2/CdS nanoparticles were systematically studied. The morphology, composition and the structure of the CeO2/CdS nanocomposite powder were studied by scanning electron microscopy (SEM), energy dispersive X-ray spectrum analysis (EDXA) and X-ray diffraction (XRD), respectively. The optical properties of CeO2/CdS nanocomposites were studied by UV-vis absorption and photoluminescence (PL) spectroscopy. The optical band gaps of the CeO2/CdS nanopowders ranged from 2.34 eV to 2.39 eV as estimated from the UV-vis absorption. In the room temperature photoluminescence spectrum of CeO2/CdS nanopowder, a strong blue emission band was observed at 400 nm. Since the powder shows strong visible luminescence, it may be used as a blue phosphor in future. The original article published with this DOI was submitted in error. The correct article was inadvertently left out of the original submission. This has been rectified and the correct article was published online on 16 April 2018.

Gaussian measures of entanglement versus negativities: Ordering of two-mode Gaussian states

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adesso, Gerardo; Illuminati, Fabrizio; INFN Sezione di Napoli-Gruppo Collegato di Salerno, Via S. Allende, 84081 Baronissi, SA

2005-09-15

We study the entanglement of general (pure or mixed) two-mode Gaussian states of continuous-variable systems by comparing the two available classes of computable measures of entanglement: entropy-inspired Gaussian convex-roof measures and positive partial transposition-inspired measures (negativity and logarithmic negativity). We first review the formalism of Gaussian measures of entanglement, adopting the framework introduced in M. M. Wolf et al., Phys. Rev. A 69, 052320 (2004), where the Gaussian entanglement of formation was defined. We compute explicitly Gaussian measures of entanglement for two important families of nonsymmetric two-mode Gaussian state: namely, the states of extremal (maximal and minimal) negativities at fixedmore » global and local purities, introduced in G. Adesso et al., Phys. Rev. Lett. 92, 087901 (2004). This analysis allows us to compare the different orderings induced on the set of entangled two-mode Gaussian states by the negativities and by the Gaussian measures of entanglement. We find that in a certain range of values of the global and local purities (characterizing the covariance matrix of the corresponding extremal states), states of minimum negativity can have more Gaussian entanglement of formation than states of maximum negativity. Consequently, Gaussian measures and negativities are definitely inequivalent measures of entanglement on nonsymmetric two-mode Gaussian states, even when restricted to a class of extremal states. On the other hand, the two families of entanglement measures are completely equivalent on symmetric states, for which the Gaussian entanglement of formation coincides with the true entanglement of formation. Finally, we show that the inequivalence between the two families of continuous-variable entanglement measures is somehow limited. Namely, we rigorously prove that, at fixed negativities, the Gaussian measures of entanglement are bounded from below. Moreover, we provide some strong evidence suggesting

Application of multivariate Gaussian detection theory to known non-Gaussian probability density functions

NASA Astrophysics Data System (ADS)

Schwartz, Craig R.; Thelen, Brian J.; Kenton, Arthur C.

1995-06-01

A statistical parametric multispectral sensor performance model was developed by ERIM to support mine field detection studies, multispectral sensor design/performance trade-off studies, and target detection algorithm development. The model assumes target detection algorithms and their performance models which are based on data assumed to obey multivariate Gaussian probability distribution functions (PDFs). The applicability of these algorithms and performance models can be generalized to data having non-Gaussian PDFs through the use of transforms which convert non-Gaussian data to Gaussian (or near-Gaussian) data. An example of one such transform is the Box-Cox power law transform. In practice, such a transform can be applied to non-Gaussian data prior to the introduction of a detection algorithm that is formally based on the assumption of multivariate Gaussian data. This paper presents an extension of these techniques to the case where the joint multivariate probability density function of the non-Gaussian input data is known, and where the joint estimate of the multivariate Gaussian statistics, under the Box-Cox transform, is desired. The jointly estimated multivariate Gaussian statistics can then be used to predict the performance of a target detection algorithm which has an associated Gaussian performance model.

High Potentials: A CEO Perspective

ERIC Educational Resources Information Center

Hermans, Jeanine

2007-01-01

Finding high potentials has been identified as one of the major challenges for society and for higher education. But how does one find the talented individuals who will design the future of society? Can and should universities cooperate or compete with business and industry for these talents? Three CEOs reflect on this worldwide competition for…

CeO2 nanoparticles alter the outcome of species interactions.

PubMed

Peng, Cheng; Chen, Ying; Pu, Zhichao; Zhao, Qing; Tong, Xin; Chen, Yongsheng; Jiang, Lin

2017-06-01

Despite considerable research on the environmental impacts of nanomaterials, we know little about how they influence interactions between species. Here, we investigated the acute (12 d) and chronic (64 d) toxicities of cerium oxide nanoparticles (CeO 2 NPs) and bulk particles (0-200 mg/L) to three ciliated protist species (Loxocephalus sp., Paramecium aurelia, and Tetrahymena pyriformis) in single-, bi-, and multispecies microcosms. The results show that CeO 2 NPs strongly affected the interactions between ciliated protozoan species. When exposed to the highest CeO 2 NPs (200 mg/L), the intrinsic growth rates of Loxocephalus and Paramecium were significantly decreased by 18.87% and 88.27%, respectively, while their carrying capacities declined by more than 90%. However, CeO 2 NP exposure made it difficult to predict outcomes of interspecific competition between species. At higher NP exposure (100 and 200 mg/L), competition led to the extinction of both species in the Loxocephalus and Paramecium microcosms that survived in the absence of competitors or CeO 2 NPs. Further, the presence of potential competitors improved the survival of Loxocephalus to hundreds of individuals per milliliter in microcosms with Tetrahymena where Loxocephalus would otherwise not be able to tolerate high levels of NP exposure. This result could be attributed to weakened NP adsorption on the cell surface due to competitor-caused reduction of NP surface charge (from -18.52 to -25.17 mV) and intensified NP aggregation via phagocytosis of NPs by ciliate cells. Our results emphasize the need to explicitly consider species interactions for a more comprehensive understanding of the ecological consequences of NP exposure.

Enhanced Colloidal Stability of CeO2 Nanoparticles by Ferrous Ions: Adsorption, Redox Reaction, and Surface Precipitation.

PubMed

Liu, Xuyang; Ray, Jessica R; Neil, Chelsea W; Li, Qingyun; Jun, Young-Shin

2015-05-05

Due to the toxicity of cerium oxide (CeO2) nanoparticles (NPs), a better understanding of the redox reaction-induced surface property changes of CeO2 NPs and their transport in natural and engineered aqueous systems is needed. This study investigates the impact of redox reactions with ferrous ions (Fe2+) on the colloidal stability of CeO2 NPs. We demonstrated that under anaerobic conditions, suspended CeO2 NPs in a 3 mM FeCl2 solution at pH 4.8 were much more stable against sedimentation than those in the absence of Fe2+. Redox reactions between CeO2 NPs and Fe2+ lead to the formation of 6-line ferrihydrite on the CeO2 surfaces, which enhanced the colloidal stability by increasing the zeta potential and hydrophilicity of CeO2 NPs. These redox reactions can affect the toxicity of CeO2 NPs by increasing cerium dissolution, and by creating new Fe(III) (hydr)oxide reactive surface layers. Thus, these findings have significant implications for elucidating the phase transformation and transport of redox reactive NPs in the environment.

CEO perceptions of competition--and strategic response in hospital markets.

PubMed

Alexander, J A; Burns, L R; Morrisey, M A; Johnson, V

2001-06-01

Physician-organization integration (POI) has emerged as a key issue for hospitals and health systems seeking to improve the quality and cost-effectiveness of care. Although competition and managed care are often cited as primary market drivers of the adoption of POI strategies, prior research has shown only weak associations between these market attributes and POI. This article argues that the role of key organizational decision makers has not been adequately accounted for in explaining strategic change. The study examines the role of hospital CEO perceptions of competition in predicting the adoption of five different approaches to POI. CEO perceptions of general market competition are explained by a combination of market and organizational attributes. Furthermore, when controlling for objective characteristics of the environment and organization, CEO perceptions of competition have consistent, statistically significant associations with four of five measures of POI examined.

The curse of the superstar CEO.

PubMed

Khurana, Rakesh

2002-09-01

When struggling companies look for a new chief executive today, the one quality they prize above all others is charisma. But once they've recruited a larger-than-life leader, they often find that their troubles only get worse. Indeed, as the author's new research painfully reveals, the widespread belief in the powers of charismatic CEOs can be problematic. Why? First, Khurana says, there's no conclusive evidence that charismatic leadership affects an organization's performance. And yet--as Kodak's story over the past decade reveals--when a company is faltering, boards feel compelled to oust the incumbent chief executive and bring in a corporate savior. Second, the insistence on finding a charismatic leader, combined with the undefinable nature of charisma, results in selection processes that are overly conservative and even irrational. Boards end up considering only candidates who have already achieved the rank of CEO or president at a high-performing, high-profile company, even if they are not right for the job. Third, charismatic leaders deliberately destabilize organizations. This can result in a more vibrant company, as it did at General Electric during Jack Welch's tenure, but it can also leave a troubled legacy for the organization to overcome, as GE, Ford, and Enron have all found. Faith in a company, a product, or an idea can unleash tremendous innovation and productivity. But the extravagant hopes invested in charismatic CEOs resemble not mature faith but a belief in magic. If we are willing to reconsider our notion of leadership, this age of faith can be followed by an era of faith and reason.

2013 CEO leadership forum, leading the 21st century DOT : a summary report.

DOT National Transportation Integrated Search

2013-04-01

This report summarizes the 2013 CEO Leadership Forum : for state departments of transportation (DOTs). Over : three days, transportation leaders from across the nation : explored a range of issues and developed action plans to : support CEOs and thei...

STK Integrated Message Production List Editor (SIMPLE) for CEO Operations

NASA Technical Reports Server (NTRS)

Trenchard, Mike; Heydorn, James

2014-01-01

Late in fiscal year 2011, the Crew Earth Observations (CEO) team was tasked to upgrade and replace its mission planning and mission operations software systems, which were developed in the Space Shuttle era of the 1980s and 1990s. The impetuses for this change were the planned transition of all workstations to the Windows 7 64-bit operating system and the desire for more efficient and effective use of Satellite Tool Kit (STK) software required for reliable International Space Station (ISS) Earth location tracking. An additional requirement of this new system was the use of the same SQL database of CEO science sites from the SMMS, which was also being developed. STK Integrated Message Production List Editor (SIMPLE) is the essential, all-in-one tool now used by CEO staff to perform daily ISS mission planning to meet its requirement to acquire astronaut photography of specific sites on Earth. The sites are part of a managed, long-term database that has been defined and developed for scientific, educational, and public interest. SIMPLE's end product is a set of basic time and location data computed for an operator-selected set of targets that the ISS crew will be asked to photograph (photography is typically planned 12 to 36 hours out). The CEO operator uses SIMPLE to (a) specify a payload operations planning period; (b) acquire and validate the best available ephemeris data (vectors) for the ISS during the planning period; (c) ingest and display mission-specific site information from the CEO database; (d) identify and display potential current dynamic event targets as map features; (e) compute and display time and location information for each target; (f) screen and select targets based on known crew availability constraints, obliquity constraints, and real-time evaluated constraints to target visibility due to illumination (sun elevation) and atmospheric conditions (weather); and finally (g) incorporate basic, computed time and location information for each selected

In vitro release and biological activities of Carum copticum essential oil (CEO) loaded chitosan nanoparticles.

PubMed

Esmaeili, Akbar; Asgari, Azadeh

2015-11-01

In recent years, the unparalleled and functional properties of essential oils have been extensively reported, but the sensitivity of essential oils to environmental factors and their poor aqueous solubility have limited their applications in industries. Hence, we encapsulated CEO in chitosan nanoparticles by an emulsion-ionic gelation with pantasodium tripolyphosphate (TPP) and sodium hexametaphosphte (HMP), separately, as crosslinkers. The nanoparticles were analyzed by Fourier transform infrared spectroscopy (FT-IR), Ultraviolet-visible spectroscopy (UV-vis), differential scanning calorimetry (DSC), scanning electron microscope (SEM) and dynamic light scattering (DLS). The encapsulation efficiency (EE) and loading capacity (LC) of CEO in chitosan nanoparticles increased with the increase of initial CEO amount. The nanoparticles displayed an average size of 30-80nm with a spherical shape and regular distribution. In vitro release profiles exhibited an initial burst release and followed by a sustained CEO release at different pH conditions. The amount of CEO release from chitosan nanoparticles was higher in acidic pH to basic or neutral pH, respectively. The biological properties of CEO, before and after the encapsulation process were evaluated by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and agar disk diffusion method, respectively. The results indicated the encapsulation of CEO in chitosan nanoparticles could be protected the quality. Copyright © 2015 Elsevier B.V. All rights reserved.

Gaussian Boson Sampling.

PubMed

Hamilton, Craig S; Kruse, Regina; Sansoni, Linda; Barkhofen, Sonja; Silberhorn, Christine; Jex, Igor

2017-10-27

Boson sampling has emerged as a tool to explore the advantages of quantum over classical computers as it does not require universal control over the quantum system, which favors current photonic experimental platforms. Here, we introduce Gaussian Boson sampling, a classically hard-to-solve problem that uses squeezed states as a nonclassical resource. We relate the probability to measure specific photon patterns from a general Gaussian state in the Fock basis to a matrix function called the Hafnian, which answers the last remaining question of sampling from Gaussian states. Based on this result, we design Gaussian Boson sampling, a #P hard problem, using squeezed states. This demonstrates that Boson sampling from Gaussian states is possible, with significant advantages in the photon generation probability, compared to existing protocols.

Generalized Ince Gaussian beams

NASA Astrophysics Data System (ADS)

Bandres, Miguel A.; Gutiérrez-Vega, Julio C.

2006-08-01

In this work we present a detailed analysis of the tree families of generalized Gaussian beams, which are the generalized Hermite, Laguerre, and Ince Gaussian beams. The generalized Gaussian beams are not the solution of a Hermitian operator at an arbitrary z plane. We derived the adjoint operator and the adjoint eigenfunctions. Each family of generalized Gaussian beams forms a complete biorthonormal set with their adjoint eigenfunctions, therefore, any paraxial field can be described as a superposition of a generalized family with the appropriate weighting and phase factors. Each family of generalized Gaussian beams includes the standard and elegant corresponding families as particular cases when the parameters of the generalized families are chosen properly. The generalized Hermite Gaussian and Laguerre Gaussian beams correspond to limiting cases of the generalized Ince Gaussian beams when the ellipticity parameter of the latter tends to infinity or to zero, respectively. The expansion formulas among the three generalized families and their Fourier transforms are also presented.

How CEOs use management information systems for strategy implementation in hospitals.

PubMed

Naranjo-Gil, David; Hartmann, Frank

2007-04-01

Institutional and market changes seem to force hospitals across the Western world to revitalize their corporate strategies towards more cost efficiency on the one hand, and more flexibility towards customer demands on the other hand. Hospitals, however, apparently differ in the extent to which they are able to implement such strategies effectively. This paper explores whether these different levels of effectiveness depend on how hospitals' top managers' use of the available management information systems (MIS). Based on data obtained from the 218 CEOs of public hospitals in Spain, we analyze how CEOs' professional and educational backgrounds affect their use of MIS, and how the use of the MIS subsequently supports or inhibits the implementation of these strategic goals. The results indicate that CEOs with a predominant clinical background focus more on non-financial information for decision-making and prefer an interactive style of using MIS, which together support flexibility strategies. CEOs with a predominant administrative background seem more effective in establishing cost-reduction strategies, through their larger inclination to emphasize financial information in combination with a diagnostic use of the MIS. Implications for the strategic management of hospitals are outlined.

Room temperature ferromagnetism in Fe-doped CeO2 nanoparticles.

PubMed

Maensiri, Santi; Phokha, Sumalin; Laokul, Paveena; Seraphin, Supapan

2009-11-01

RT ferromagnetism was observed in nanoparticles of Fe-doped CeO2 (i.e., Ce(0.97)Fe(0.03)O2) synthesized by a sol-gel method. The undoped and Fe-doped CeO2 were characterized by XRD, Raman spectroscopy, TEM, and VSM. The undoped samples and Ce(0.97)Fe(0.03)O2 precursor exhibit a diamagnetic behavior. The 673 K-calcined Ce(0.97)Fe(0.03)O2 sample is paramagnetic whereas 773 and 873 K-calcined Ce(0.97)Fe(0.03)O2 samples are ferromagnetism having the magnetizations of 4.65 x 10(-3) emu/g and 6.20 x 10(-3) emu/g at 10 kOe, respectively. Our results indicate that the ferromagnetic property is intrinsic to the Fe-doped CeO2 system and is not a result of any secondary magnetic phase or cluster formation.

Template-Free Hydrothermal Synthesis, Mechanism, and Photocatalytic Properties of Core-Shell CeO2 Nanospheres

NASA Astrophysics Data System (ADS)

Li, Huijie; Meng, Fanming; Gong, Jinfeng; Fan, Zhenghua; Qin, Rui

2018-03-01

CeO2 nanospheres with the core-shell nanostructure have been successfully synthesized by a template-free hydrothermal method. The structures, morphologies and optical properties of core-shell CeO2 nanospheres were analyzed by X-ray diffraction (XRD), TG, Fourier transform infrared spectroscopy, XRD, EDS, SAED, scanning electron microscopy and transmission electron microscopy, UV-Vis diffuse reflectance spectra, Raman analyses. The degradation efficiencies of core-shell CeO2 nanospheres for methyl orange were as high as 93.49, 95.67 and 98.28% within 160 min, and the rates of photo degradation of methyl orange by core-shell CeO2 nanospheres under UV-light were 0.01693, 0.01782 and 0.02375 min-1. Methyl orange was degraded in photocatalytic oxidation processes, which mainly gave the credit to a large number of reactive species including h+, surface superoxide species ·O2 -, and ·OH radicals. The core-shell structure, small crystallite size and the conversion between Ce3+ and Ce4+ of CeO2 nanospheres were of importance for its catalytic activity. These results demonstrated the possibility of improving the efficient catalysts of the earth abundant CeO2 catalysts.

(U) Equation of State and Compaction Modeling for CeO 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fredenburg, David A.; Chisolm, Eric D.

2014-10-20

Recent efforts have focused on developing a solid-liquid and three-phase equation of state (EOS) for CeO 2, while parallel experimental efforts have focused on obtaining high-fidelity Hugoniot measurements on CeO 2 in the porous state. The current work examines the robustness of two CeO 2 SESAME equations of state, a solid-liquid EOS, 96170, and a three-phase EOS, 96171, by validating the EOS against a suite of high-pressure shock compression experiments on initially porous CeO 2. At lower pressures compaction is considered by incorporating a two-term exponential form of the P-compaction model, using three separate definitions for α(P). Simulations are executedmore » spanning the partially compacted and fully compacted EOS regimes over the pressure range 0.5 - 109 GPa. Comparison of calculated Hugoniot results with those obtained experimentally indicate good agreement for all definitions of α(P) with both the solid-liquid and three-phase EOS in the low-pressure compaction regime. At higher pressures the three-phase EOS does a better job at predicting the measured Hugoniot response, though at the highest pressures EOS 96171 predicts a less compliant response than is observed experimentally. Measured material velocity profiles of the shock-wave after it has transmitted through the powder are also compared with those simulated using with solid-liquid and three-phase EOS. Profiles lend insight into limits of the current experimental design, as well as the threshold conditions for the shock-induced phase transition in CeO 2.« less

An Unexpected Influence on a Quadratic

ERIC Educational Resources Information Center

Davis, Jon D.

2013-01-01

Using technology to explore the coefficients of a quadratic equation can lead to an unexpected result. This article describes an investigation that involves sliders and dynamically linked representations. It guides students to notice the effect that the parameter "a" has on the graphical representation of a quadratic function in the form…

Fundamentals and Catalytic Applications of CeO2-Based Materials.

PubMed

Montini, Tiziano; Melchionna, Michele; Monai, Matteo; Fornasiero, Paolo

2016-05-25

Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40(th) anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are deepening our understanding of these materials, helping us to predict their behavior and application potential. This review has a wide view on all those aspects related to ceria which promise to produce an important impact on our life, encompassing fundamental knowledge of CeO2 and its properties, characterization toolbox, emerging features, theoretical studies, and all the catalytic applications, organized by their degree of establishment on the market.

New CeO2 nanoparticles-based topical formulations for the skin protection against organophosphates.

PubMed

Zenerino, Arnaud; Boutard, Tifenn; Bignon, Cécile; Amigoni, Sonia; Josse, Denis; Devers, Thierry; Guittard, Frédéric

2015-01-01

To reinforce skin protection against organophosphates (OPs), the development of new topical skin protectants (TSP) has received a great interest. Nanoparticles like cerium dioxide (CeO 2 ) known to adsorb and neutralize OPs are interesting candidates for TSP. However, NPs are difficult to disperse into formulations and they are suspected of toxicological issues. Thus, we want to study: (1) the effect of the addition of CeO 2 NPs in formulations for the skin protection (2) the impact of the doping of CeO 2 NPs by calcium; (3) the effect of two methods of dispersion of CeO 2 NPs: an O/W emulsion or a suspension of a fluorinated thickening polymer (HASE-F) grafted with these NPs. As a screening approach we used silicone membranes as a skin equivalent and Franz diffusion cells for permeation tests. The addition of pure CeO 2 NPs in both formulations permits the penetration to decrease by a 3-4-fold factor. The O/W emulsion allows is the best approach to obtain a film-forming coating with a good reproducibility of the penetration results; whereas the grafting of NPs to a thickener is the best way to obtain an efficient homogenous suspension of CeO 2 NPs with a decreased of toxicological impact but the coating is less film-forming which slightly impacts the reproducibility of the penetration results.

In vitro skin decontamination of the organophosphorus pesticide Paraoxon with nanometric cerium oxide CeO2.

PubMed

Salerno, Alicia; Devers, Thierry; Bolzinger, Marie-Alexandrine; Pelletier, Jocelyne; Josse, Denis; Briançon, Stéphanie

2017-04-01

Organophosphorus compounds (OP), which mainly penetrate via the percutaneous pathway, represent a threat for both military and civilians. Body surface decontamination is vital to prevent victims poisoning. The development of a cost-effective formulation, which could be efficient and easy to handle in case of mass contamination, is therefore crucial. Metal oxides nanoparticles, due their large surface areas and the large amount of highly reactive sites, present high reactivity towards OP. First, this study aimed at evaluating the reaction of CeO 2 nanoparticles, synthetized by microwave path and calcined at 500 or 600 °C, with Paraoxon (POX) in aqueous solution. Results showed that both nanoparticles degraded 60%-70% of POX. CeO 2 calcined at 500 °C, owing to its larger specific area, was the most effective. Moreover, the degradation was significantly increased under Ultra-Violet irradiation (initial degradation rate doubled). Then, skin decontamination was studied in vitro using the Franz cell method with pig-ear skin samples. CeO 2 powder and an aqueous suspension of CeO 2 (CeO 2 -W) were applied 1 h after POX exposure. The efficiency of decontamination, including removal and/or degradation of POX, was compared to Fuller's earth (FE) and RSDL lotion which are, currently, the most efficient systems for skin decontamination. CeO 2 -W and RSDL were the most efficient to remove POX from the skin surface and decrease skin absorption by 6.4 compared to the control not decontaminated. FE reduced significantly (twice) the absorbed fraction of POX, contrarily to CeO 2 powder. Considering only the degradation rate of POX, the products ranged in the order CeO 2  > RSDL > CeO 2 -W > FE (no degradation). This study showed that CeO 2 nanoparticles are a promising material for skin decontamination of OP if formulated as a dispersion able to remove POX like CeO 2 -W and to degrade it as CeO 2 powder. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

First-principles characterization of formate and carboxyl adsorption on the stoichiometric CeO2(111) and CeO2(110) surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mei, Donghai

2013-05-20

Molecular adsorption of formate and carboxyl on the stoichiometric CeO2(111) and CeO2(110) surfaces was studied using periodic density functional theory (DFT+U) calculations. Two distinguishable adsorption modes (strong and weak) of formate are identified. The bidentate configuration is more stable than the monodentate adsorption configuration. Both formate and carboxyl bind at the more open CeO2(110) surface are stronger. The calculated vibrational frequencies of two adsorbed species are consistent with experimental measurements. Finally, the effects of U parameters on the adsorption of formate and carboxyl over both CeO2 surfaces were investigated. We found that the geometrical configurations of two adsorbed species aremore » not affected by using different U parameters (U=0, 5, and 7). However, the calculated adsorption energy of carboxyl pronouncedly increases with the U value while the adsorption energy of formate only slightly changes (<0.2 eV). The Bader charge analysis shows the opposite charge transfer occurs for formate and carboxyl adsorption where the adsorbed formate is negatively charge whiled the adsorbed carboxyl is positively charged. Interestingly, with the increasing U parameter, the amount of charge is also increased. This work was supported by the Laboratory Directed Research and Development (LDRD) project of the Pacific Northwest National Laboratory (PNNL) and by a Cooperative Research and Development Agreement (CRADA) with General Motors. The computations were performed using the Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL), which is a U.S. Department of Energy national scientific user facility located at PNNL in Richland, Washington. Part of the computing time was also granted by the National Energy Research Scientific Computing Center (NERSC)« less

Resource theory of non-Gaussian operations

NASA Astrophysics Data System (ADS)

Zhuang, Quntao; Shor, Peter W.; Shapiro, Jeffrey H.

2018-05-01

Non-Gaussian states and operations are crucial for various continuous-variable quantum information processing tasks. To quantitatively understand non-Gaussianity beyond states, we establish a resource theory for non-Gaussian operations. In our framework, we consider Gaussian operations as free operations, and non-Gaussian operations as resources. We define entanglement-assisted non-Gaussianity generating power and show that it is a monotone that is nonincreasing under the set of free superoperations, i.e., concatenation and tensoring with Gaussian channels. For conditional unitary maps, this monotone can be analytically calculated. As examples, we show that the non-Gaussianity of ideal photon-number subtraction and photon-number addition equal the non-Gaussianity of the single-photon Fock state. Based on our non-Gaussianity monotone, we divide non-Gaussian operations into two classes: (i) the finite non-Gaussianity class, e.g., photon-number subtraction, photon-number addition, and all Gaussian-dilatable non-Gaussian channels; and (ii) the diverging non-Gaussianity class, e.g., the binary phase-shift channel and the Kerr nonlinearity. This classification also implies that not all non-Gaussian channels are exactly Gaussian dilatable. Our resource theory enables a quantitative characterization and a first classification of non-Gaussian operations, paving the way towards the full understanding of non-Gaussianity.

Seven Wonders of the Ancient and Modern Quadratic World.

ERIC Educational Resources Information Center

Taylor, Sharon E.; Mittag, Kathleen Cage

2001-01-01

Presents four methods for solving a quadratic equation using graphing calculator technology: (1) graphing with the CALC feature; (2) quadratic formula program; (3) table; and (4) solver. Includes a worksheet for a lab activity on factoring quadratic equations. (KHR)

THE EFFECTIVENESS OF QUADRATS FOR MEASURING VASCULAR PLANT DIVERSITY

EPA Science Inventory

Quadrats are widely used for measuring characteristics of vascular plant communities. It is well recognized that quadrat size affects measurements of frequency and cover. The ability of quadrats of varying sizes to adequately measure diversity has not been established. An exha...

Fundamental Understanding of the Interaction of Acid Gases with CeO 2 : From Surface Science to Practical Catalysis

DOE PAGES

Tumuluri, Uma; Rother, Gernot; Wu, Zili

2016-03-21

Acid gases including CO 2, SO 2, and NO x are ubiquitous in large-scale energy applications including heterogeneous catalysis. The adverse environmental and health effects of these acid gases have resulted in high interest in the research and development of technologies to remove or convert these acid gases. The main challenge for the development of these technologies is to develop catalysts that are highly efficient, stable, and cost-effective, and many catalysts have been reported in this regard. CeO 2 and CeO 2-based catalysts have gained prominence in the removal and conversion of CO 2, SO 2, and NO x becausemore » of their structural robustness and redox and acid–base properties. In this article, we provide a brief overview of the application of CeO 2 and CeO 2-based catalysts for the removal of CO 2, SO 2, and NO x gases with an emphasis on the fundamental understanding of the interactions of these acid gases with CeO 2. The studies summarized in this review range from surface science using single crystals and thin films with precise crystallographic planes to practical catalysis applications of nanocrystalline and polycrystalline CeO 2 materials with defects and dopants. After an introduction to the properties of CeO 2 surfaces, their catalytic properties for conversions of different acid gases are reviewed and discussed. Lastly, we find that the surface atomic structure, oxygen vacancies, and surface acid–base properties of CeO 2 play vital roles in the surface chemistry and structure evolution during the interactions of acid gases with CeO 2 and CeO 2-based catalysts.« less

Fundamental Understanding of the Interaction of Acid Gases with CeO 2 : From Surface Science to Practical Catalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tumuluri, Uma; Rother, Gernot; Wu, Zili

Acid gases including CO 2, SO 2, and NO x are ubiquitous in large-scale energy applications including heterogeneous catalysis. The adverse environmental and health effects of these acid gases have resulted in high interest in the research and development of technologies to remove or convert these acid gases. The main challenge for the development of these technologies is to develop catalysts that are highly efficient, stable, and cost-effective, and many catalysts have been reported in this regard. CeO 2 and CeO 2-based catalysts have gained prominence in the removal and conversion of CO 2, SO 2, and NO x becausemore » of their structural robustness and redox and acid–base properties. In this article, we provide a brief overview of the application of CeO 2 and CeO 2-based catalysts for the removal of CO 2, SO 2, and NO x gases with an emphasis on the fundamental understanding of the interactions of these acid gases with CeO 2. The studies summarized in this review range from surface science using single crystals and thin films with precise crystallographic planes to practical catalysis applications of nanocrystalline and polycrystalline CeO 2 materials with defects and dopants. After an introduction to the properties of CeO 2 surfaces, their catalytic properties for conversions of different acid gases are reviewed and discussed. Lastly, we find that the surface atomic structure, oxygen vacancies, and surface acid–base properties of CeO 2 play vital roles in the surface chemistry and structure evolution during the interactions of acid gases with CeO 2 and CeO 2-based catalysts.« less

CEO stabilization of a femtosecond laser using a SESAM as fast opto-optical modulator.

PubMed

Hoffmann, Martin; Schilt, Stéphane; Südmeyer, Thomas

2013-12-02

We present a new method for intra-cavity control of the carrier-envelope offset (CEO) frequency of ultrafast lasers that combines high feedback bandwidth with low loss, low nonlinearity, and low dispersion. A semiconductor saturable-absorber mirror (SESAM) inside a modelocked laser is optically pumped with a continuous-wave (cw) laser. In this way, the SESAM acts as intra-cavity opto-optical modulator (OOM): the optical power of the cw-laser corresponds to a high-bandwidth modulation channel for CEO frequency control. We experimentally verified this method for a femtosecond Er:Yb:glass oscillator (ERGO), in which one SESAM is in parallel used for modelocking and as intra-cavity OOM for achieving a tight CEO lock. This laser can also be CEO-stabilized in the usual scheme, in which the laser pump current is modulated, i.e., the gain element acts as intra-cavity OOM. We compare the performance with gain and SESAM OOM measuring CEO transfer function, frequency noise power spectral density (PSD), and Allan deviation for integration times up to 1000 s. In the case of the gain OOM, the millisecond upper-state lifetime of the Er:Yb:glass limits the achievable CEO-control bandwidth to <10 kHz. The feedback bandwidth of the SESAM OOM was more than a factor of 10 higher than the gain OOM bandwidth and was mainly limited by the used current driver. The residual integrated phase noise (1 Hz - 100 kHz) of the ~20-MHz CEO beat was improved by more than an order of magnitude (from 720 mrad to less than 65 mrad), and the fractional frequency stability by a factor of 4 (from 1∙10

Catalytic hydrolysis of COS over CeO2 (110) surface: A density functional theory study

NASA Astrophysics Data System (ADS)

Song, Xin; Ning, Ping; Wang, Chi; Li, Kai; Tang, Lihong; Sun, Xin

2017-08-01

Density functional theory (DFT) calculations were performed to investigate the reaction pathways for catalytic hydrolysis of COS over CeO2 (110) surface using Dmol3 model. The thermodynamic stability analysis for the suggested routes of COS hydrolysis to CO2 and H2S was evaluated. The absolute values of adsorption energy of H2O-CeO2 are higher than that of COS-CeO2. Meanwhile, the adsorption energy and geometries show that H2O is easier adsorbed on the surface of CeO2 (110) than COS. H2O plays a role as a bridge in the process of joint adsorption. H2O forms more Cesbnd Osbnd H groups on the CeO2 (110) surface. CeO2 decreases the maximum energy barrier by 76.15 kcal/mol. The migration of H from H2O to COS is the key for the hydrolysis reaction. Csbnd O channel is easier to occur than Csbnd S channel. Experimental result shows that adding of CeO2 can increase COS removal rate and prolong the 100% COS removal rate from 180 min to 210 min. The difference between Fe2O3 and CeO2 for the hydrolysis of COS is characterized in the atomic charge transfer and the formation of Hsbnd O bond and Hsbnd S bond. The transfer effect of H in H2O to S in COS over CeO2 decreases the energy barriers of hydrolysis reaction, and enhances the reaction activity of COS hydrolysis.

Application of the sequential quadratic programming algorithm for reconstructing the distribution of optical parameters based on the time-domain radiative transfer equation.

PubMed

Qi, Hong; Qiao, Yao-Bin; Ren, Ya-Tao; Shi, Jing-Wen; Zhang, Ze-Yu; Ruan, Li-Ming

2016-10-17

Sequential quadratic programming (SQP) is used as an optimization algorithm to reconstruct the optical parameters based on the time-domain radiative transfer equation (TD-RTE). Numerous time-resolved measurement signals are obtained using the TD-RTE as forward model. For a high computational efficiency, the gradient of objective function is calculated using an adjoint equation technique. SQP algorithm is employed to solve the inverse problem and the regularization term based on the generalized Gaussian Markov random field (GGMRF) model is used to overcome the ill-posed problem. Simulated results show that the proposed reconstruction scheme performs efficiently and accurately.

Predictors of hospital CEO affiliation with a professional association.

PubMed

Khaliq, Amir A; Walston, Stephen L

2012-01-01

Based on a 2008 cross-sectional survey of 582 hospital CEOs in the United States, this study reports the findings of two logistic regression models designed to identify CEO and hospital characteristics associated with Member and Fellow status in the American College of Healthcare Executives (ACHE). The purpose of the study was to understand the personal and organizational characteristics of those CEOs who choose to be Members and Fellows of a professional association such as ACHE. The results showed that most (74 percent) of the respondents considered ACHE to be their primary professional association. The results also revealed that a master's degree in health administration [beta = .88, t(427) = 5.35, p < .0001], male gender [beta = .59, t(427) = 3.01, p = .002], and financial incentives provided by the parent hospital [beta = .25, t(427) = 2.73, p = .006] were statistically positively linked with Member status in ACHE. A master's degree in health administration [beta = .81, t(424) = 5.79, p < .0001], male gender [beta = .39, t(424) = 2.25, p = .02], and age [beta = .02, t(424) 2.32, p = .02] were also statistically positively associated with Fellow status in ACHE. Notably, organizational factors such as size, geographic location, for-profit status, and financial strength of the hospital do not seem to play an important role in the CEOs' decision to become a Member or Fellow of ACHE. The implication of these findings is that membership and fellowship at a professional association are influenced by characteristics of the individual, and incentives provided by employers can encourage employees to get involved with their professional associations.

Who should set CEO pay? The press? Congress? Shareholders?

PubMed

Brownstein, A R; Panner, M J

1992-01-01

Populist fervor in an election year has transformed executive compensation from a business issue into a political one. Critics, led by Graef Crystal, author of In Search of Excess: The Overcompensation of American Executives, charge that CEOs are ripping off shareholders with their outrageous salaries while running U.S. corporations into the ground. Politicians claim overpaid CEOs are the root cause of the U.S. competitiveness problem. Add a recessionary business climate to the fact that some CEOs earn 130 times more than their lowest paid employees, and you have the makings of a populist rebellion. In a bid to appease voters, Congress is considering several bills that would limit the deductibility of "excessive executive salaries," the SEC has opened the issue to shareholder comment, and the Financial Accounting Standards Board is looking at new accounting standards for granting stock options to executives as part of company compensation schemes. Andrew R. Brownstein and Morris J. Panner say it's time to put the debate back where it belongs--in a business context. The real question is not are executives paid too much, but are shareholders getting their money's worth. Most U.S. corporations use stock compensation to link company long-term performance to executive salaries. And because of the staggering market performance of U.S. corporations in the 1980s, an overwhelming majority of CEOs are actually paid in line with their performance. Rather than cut executive pay, Brownstein and Panner suggest that corporations extend incentive-based compensation plans to all employees, thus narrowing the salary gap and establishing pay for performance at every level of the organization.

Enhancement of photocatalytic activity of combustion-synthesized CeO2/C3N4 nanoparticles

NASA Astrophysics Data System (ADS)

Li, Dong-Feng; Yang, Ke; Wang, Xiao-qin; Ma, Ya-Li; Huang, Gui-Fang; Huang, Wei-Qing

2015-09-01

Nanocrystalline CeO2/C3N4 was synthesized via a one-step solution combustion method using urea as fuel for the first time. The effects of the molar ratio of urea to cerium chloride on the photocatalytic activity of the synthesized samples were investigated. The synthesized nanocrystalline CeO2/C3N4 shows small size and large surface exposure area. Photocatalytic degradation of methylene blue demonstrates that the synthesized nanocrystalline CeO2/C3N4 possesses enhanced photocatalytic activity. It is proposed that the enhanced photocatalytic activity might be related to the favorable morphology and structure, and the effective charge separation between C3N4 and CeO2 in the photocatalytic process.

CEO Ideational Facilitation Leadership and Team Creativity: The Mediating Role of Knowledge Sharing

ERIC Educational Resources Information Center

Carmeli, Abraham; Paulus, Paul B.

2015-01-01

The development of new ventures is often based on collective creative efforts. We conceptualize team creativity as a process of looking for and exploring new solutions and examine whether and how CEO leadership fosters creativity in top management teams (TMT). Data collected from senior executive teams indicate that CEO ideational facilitation…

What only the CEO can do.

PubMed

Lafley, A G

2009-05-01

The author combines his nine years' experience as the CEO of Procter & Gamble with the last writings of the management scholar Peter Drucker to answer the question "What is the work of the CEO?" The chief executive, Lafley says, is held singularly accountable for the performance and results of the company--according not just to its own goals but also to those of diverse and often competing external stakeholders. In other words, he or she is responsible for linking the outside to the inside--a job that consists of four fundamental tasks. DEFINING THE MEANINGFUL OUTSIDE: At P&G this means emphasizing that the consumer is boss. The company has also worked to change what had been win-lose negotiations into win-win partnerships with retail customers and suppliers. DECIDING WHAT BUSINESS YOU ARE IN (OR NOT IN): After a thorough analysis of its strengths, current competitive position, and structural conditions, P&G chose to grow from its core--laundry products, baby diapers, feminine care, and hair care--and also to focus more on low-income consumers and developing markets, where sales have grown from 21% to 31% of the total since 2000. The company has exited food and beverages and is selling its pharmaceutical business. Where to compete and where not to compete remain ongoing questions. BALANCING PRESENT AND FUTURE: P&G defines realistic growth targets and uses a flexible budgeting process with complementary short-term, midterm, and long-term goals. SHAPING VALUES AND STANDARDS: The CEO must interpret the organization's values in the context of change and competition and define the standards that will guide decisions. Trust at P&G had come to mean that employees could rely on the company for lifetime jobs. Lafley redefined it as consumers' trust in the company's brands and shareholders' trust in its value as a long-term investment.

A novel multitarget model of radiation-induced cell killing based on the Gaussian distribution.

PubMed

Zhao, Lei; Mi, Dong; Sun, Yeqing

2017-05-07

The multitarget version of the traditional target theory based on the Poisson distribution is still used to describe the dose-survival curves of cells after ionizing radiation in radiobiology and radiotherapy. However, noting that the usual ionizing radiation damage is the result of two sequential stochastic processes, the probability distribution of the damage number per cell should follow a compound Poisson distribution, like e.g. Neyman's distribution of type A (N. A.). In consideration of that the Gaussian distribution can be considered as the approximation of the N. A. in the case of high flux, a multitarget model based on the Gaussian distribution is proposed to describe the cell inactivation effects in low linear energy transfer (LET) radiation with high dose-rate. Theoretical analysis and experimental data fitting indicate that the present theory is superior to the traditional multitarget model and similar to the Linear - Quadratic (LQ) model in describing the biological effects of low-LET radiation with high dose-rate, and the parameter ratio in the present model can be used as an alternative indicator to reflect the radiation damage and radiosensitivity of the cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

The CEOS International Directory Network: Progress and Plans, Spring, 1999

NASA Technical Reports Server (NTRS)

Olsen, Lola M.

1999-01-01

The Global Change Master Directory (GCMD) serves as the software development hub for the Committee on Earth observation Satellites' (CEOS) International Directory Network (IDN). The GCMD has upgraded the software for the IDN nodes as Version 7 of the GCMD: MD7-Oracle and MD7-Isite, as well as three other MD7 experimental interfaces. The contribution by DLR representatives (Germany) of the DLR Thesaurus will be demonstrated as an educational tool for use with MD7-Isite. The software will be installed at twelve nodes around the world: Brazil, Argentina, the Netherlands, Canada, France, Germany, Italy, Japan, Australia, New Zealand, Switzerland, and several sites in the United States. Representing NASA for the International Directory Network and the CEOS Data Access Subgroup, NASA's contribution to this international interoperability effort will be updated. Discussion will include interoperability with the CEOS Interoperability Protocol (CIP), features of the latest version of the software, including upgraded capabilities for distributed input by the IDN nodes, installation logistics, "mirroring", population objectives, and future plans.

The CEOS International Directory Network Progress and Plans: Spring, 1999

NASA Technical Reports Server (NTRS)

Olsen, Lola M.

1999-01-01

The Global Change Master Directory (GCMD) serves as the software development hub for the Committee on Earth Observation Satellites' (CEOS) International Directory Network (IDN). The GCMD has upgraded the software for the IDN nodes as Version 7 of the GCMD: MD7-Oracle and MD7-Isite, as well as three other MD7 experimental interfaces. The contribution by DLR representatives (Germany) of the DLR Thesaurus will be demonstrated as an educational tool for use with MD7-Isite. The software will be installed at twelve nodes around the world: Brazil, Argentina, the Netherlands, Canada, France, Germany, Italy, Japan, Australia, New Zealand, Switzerland, and several sites in the United States. Representing NASA for the International Directory Network and the CEOS Data Access Subgroup, NASA's contribution to this international interoperability effort will be updated. Discussion will include interoperability with the CEOS Interoperability Protocol (CIP), features of the latest version of the software, including upgraded capabilities for distributed input by the IDN nodes, installation logistics, "mirroring', population objectives, and future plans.

Density functional analysis of fluorite-structured (Ce, Zr)O 2/CeO 2 interfaces [Density functional analysis of fluorite-structured (Ce, Zr)O 2/CeO 2 interfaces: Implications for catalysis and energy applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weck, Philippe F.; Juan, Pierre -Alexandre; Dingreville, Remi

The structures and properties of Ce 1–xZr xO 2 (x = 0–1) solid solutions, selected Ce 1–xZr xO 2 surfaces, and Ce 1–xZr xO 2/CeO 2 interfaces were computed within the framework of density functional theory corrected for strong electron correlation (DFT+ U). The calculated Debye temperature increases steadily with Zr content in (Ce, Zr)O 2 phases, indicating a significant rise in microhardness from CeO 2 to ZrO 2, without appreciable loss in ductility as the interfacial stoichiometry changes. Surface energy calculations for the low-index CeO 2(111) and (110) surfaces show limited sensitivity to strong 4f-electron correlation. The fracture energymore » of Ce 1–xZr xO 2(111)/CeO 2(111) increases markedly with Zr content, with a significant decrease in energy for thicker Ce 1–xZr xO 2 films. These findings suggest the crucial role of Zr acting as a binder at the Ce 1–xZr xO 2/CeO 2 interfaces, due to the more covalent character of Zr–O bonds compared to Ce–O. Finally, the impact of surface relaxation upon interface cracking was assessed and found to reach a maximum for Ce 0.25Zr 0.75O 2/CeO 2 interfaces.« less

Density functional analysis of fluorite-structured (Ce, Zr)O 2/CeO 2 interfaces [Density functional analysis of fluorite-structured (Ce, Zr)O 2/CeO 2 interfaces: Implications for catalysis and energy applications

DOE PAGES

Weck, Philippe F.; Juan, Pierre -Alexandre; Dingreville, Remi; ...

2017-06-21

The structures and properties of Ce 1–xZr xO 2 (x = 0–1) solid solutions, selected Ce 1–xZr xO 2 surfaces, and Ce 1–xZr xO 2/CeO 2 interfaces were computed within the framework of density functional theory corrected for strong electron correlation (DFT+ U). The calculated Debye temperature increases steadily with Zr content in (Ce, Zr)O 2 phases, indicating a significant rise in microhardness from CeO 2 to ZrO 2, without appreciable loss in ductility as the interfacial stoichiometry changes. Surface energy calculations for the low-index CeO 2(111) and (110) surfaces show limited sensitivity to strong 4f-electron correlation. The fracture energymore » of Ce 1–xZr xO 2(111)/CeO 2(111) increases markedly with Zr content, with a significant decrease in energy for thicker Ce 1–xZr xO 2 films. These findings suggest the crucial role of Zr acting as a binder at the Ce 1–xZr xO 2/CeO 2 interfaces, due to the more covalent character of Zr–O bonds compared to Ce–O. Finally, the impact of surface relaxation upon interface cracking was assessed and found to reach a maximum for Ce 0.25Zr 0.75O 2/CeO 2 interfaces.« less

On the time-weighted quadratic sum of linear discrete systems

NASA Technical Reports Server (NTRS)

Jury, E. I.; Gutman, S.

1975-01-01

A method is proposed for obtaining the time-weighted quadratic sum for linear discrete systems. The formula of the weighted quadratic sum is obtained from matrix z-transform formulation. In addition, it is shown that this quadratic sum can be derived in a recursive form for several useful weighted functions. The discussion presented parallels that of MacFarlane (1963) for weighted quadratic integral for linear continuous systems.

UV-Resistant and Thermally Stable Superhydrophobic CeO2 Nanotubes with High Water Adhesion.

PubMed

Li, Xue-Ping; Sun, Ya-Li; Xu, Yao-Yi; Chao, Zi-Sheng

2018-06-03

A novel type of sticky superhydrophobic cerium dioxide (CeO 2 ) nanotube material is prepared by hydrothermal treatment without any chemical modification. A water droplet on the material surface shows a static water contact angle of about 157° but the water droplet is pinned on the material surface even when the material surface is turned upside down. Interestingly, the as-prepared CeO 2 nanotube material displays durable superhydrophobicity and enhanced adhesion to water under ultraviolet (UV) light irradiation. Importantly, this change in water adhesion can be reversed by heat treatment to restore the original adhesive value of 20 µL. Further, the maximum volume of the water droplet adhered on the material surface of CeO 2 nanotubes can be regulated without loss of superhydrophobicity during the heating treatment/UV-irradiation cycling. Meanwhile, the superhydrophobic CeO 2 nanotube material shows remarkable thermal stability even at temperatures as high as 450 °C, long-term durability in chemical environment, and air-storage and good resistance to oily contaminant. Finally, the potential application in no-loss water transportation of this sticky superhydrophobic CeO 2 material is demonstrated. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gaussian signal relaxation around spin echoes: Implications for precise reversible transverse relaxation quantification of pulmonary tissue at 1.5 and 3 Tesla.

PubMed

Zapp, Jascha; Domsch, Sebastian; Weingärtner, Sebastian; Schad, Lothar R

2017-05-01

To characterize the reversible transverse relaxation in pulmonary tissue and to study the benefit of a quadratic exponential (Gaussian) model over the commonly used linear exponential model for increased quantification precision. A point-resolved spectroscopy sequence was used for comprehensive sampling of the relaxation around spin echoes. Measurements were performed in an ex vivo tissue sample and in healthy volunteers at 1.5 Tesla (T) and 3 T. The goodness of fit using χred2 and the precision of the fitted relaxation time by means of its confidence interval were compared between the two relaxation models. The Gaussian model provides enhanced descriptions of pulmonary relaxation with lower χred2 by average factors of 4 ex vivo and 3 in volunteers. The Gaussian model indicates higher sensitivity to tissue structure alteration with increased precision of reversible transverse relaxation time measurements also by average factors of 4 ex vivo and 3 in volunteers. The mean relaxation times of the Gaussian model in volunteers are T2,G' = (1.97 ± 0.27) msec at 1.5 T and T2,G' = (0.83 ± 0.21) msec at 3 T. Pulmonary signal relaxation was found to be accurately modeled as Gaussian, providing a potential biomarker T2,G' with high sensitivity. Magn Reson Med 77:1938-1945, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Fate and Phytotoxicity of CeO2 Nanoparticles on Lettuce Cultured in the Potting Soil Environment

PubMed Central

Gui, Xin; Zhang, Zhiyong; Liu, Shutong; Ma, Yuhui; Zhang, Peng; He, Xiao; Li, Yuanyuan; Zhang, Jing; Li, Huafen; Rui, Yukui; Liu, Liming; Cao, Weidong

2015-01-01

Cerium oxide nanoparticles (CeO2 NPs) have been shown to have significant interactions in plants. Previous study reported the specific-species phytotoxicity of CeO2 NPs by lettuce (Lactuca sativa), but their physiological impacts and vivo biotransformation are not yet well understood, especially in relative realistic environment. Butterhead lettuce were germinated and grown in potting soil for 30 days cultivation with treatments of 0, 50, 100, 1000 mg CeO2 NPs per kg soil. Results showed that lettuce in 100 mg·kg-1 treated groups grew significantly faster than others, but significantly increased nitrate content. The lower concentrations treatment had no impact on plant growth, compared with the control. However, the higher concentration treatment significantly deterred plant growth and biomass production. The stress response of lettuce plants, such as Superoxide dismutase (SOD), Peroxidase (POD), Malondialdehyde(MDA) activity was disrupted by 1000 mg·kg-1 CeO2 NPs treatment. In addition, the presence of Ce (III) in the roots of butterhead lettuce explained the reason of CeO2 NPs phytotoxicity. These findings demonstrate CeO2 NPs modification of nutritional quality, antioxidant defense system, the possible transfer into the food chain and biotransformation in vivo. PMID:26317617

Fate and Phytotoxicity of CeO2 Nanoparticles on Lettuce Cultured in the Potting Soil Environment.

PubMed

Gui, Xin; Zhang, Zhiyong; Liu, Shutong; Ma, Yuhui; Zhang, Peng; He, Xiao; Li, Yuanyuan; Zhang, Jing; Li, Huafen; Rui, Yukui; Liu, Liming; Cao, Weidong

2015-01-01

Cerium oxide nanoparticles (CeO2 NPs) have been shown to have significant interactions in plants. Previous study reported the specific-species phytotoxicity of CeO2 NPs by lettuce (Lactuca sativa), but their physiological impacts and vivo biotransformation are not yet well understood, especially in relative realistic environment. Butterhead lettuce were germinated and grown in potting soil for 30 days cultivation with treatments of 0, 50, 100, 1000 mg CeO2 NPs per kg soil. Results showed that lettuce in 100 mg·kg-1 treated groups grew significantly faster than others, but significantly increased nitrate content. The lower concentrations treatment had no impact on plant growth, compared with the control. However, the higher concentration treatment significantly deterred plant growth and biomass production. The stress response of lettuce plants, such as Superoxide dismutase (SOD), Peroxidase (POD), Malondialdehyde(MDA) activity was disrupted by 1000 mg·kg-1 CeO2 NPs treatment. In addition, the presence of Ce (III) in the roots of butterhead lettuce explained the reason of CeO2 NPs phytotoxicity. These findings demonstrate CeO2 NPs modification of nutritional quality, antioxidant defense system, the possible transfer into the food chain and biotransformation in vivo.

Hydrodeoxygenation of p -Cresol over Pt/Al 2 O 3 Catalyst Promoted by ZrO 2 , CeO 2 , and CeO 2 –ZrO 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Weiyan; Wu, Kui; Liu, Pengli

2016-07-20

ZrO 2-Al 2O 3 and CeO 2-Al 2O 3 were prepared by a co-precipitation method and selected as supports for Pt catalysts. The effects of CeO 2 and ZrO 2 on the surface area and Brønsted acidity of Pt/Al 2O 3 were studied. In the hydrodeoxygenation (HDO) of p-cresol, the addition of ZrO 2 promoted the direct deoxygenation activity on Pt/ZrOO 2-Al 2O 3 via Caromatic-O bond scission without benzene ring saturation. Pt/CeOO 2-Al 2O 3 exhibited higher deoxygenation extent than Pt/Al 2O 3 due to the fact that Brønsted acid sites on the catalyst surface favored the adsorption ofmore » p-cresol. With the advantages of CeO 2 and ZrO 2 taken into consideration, CeO 2-ZrOO 2-Al 2O 3 was prepared, leading to the highest HDO activity of Pt/CeO 2-ZrOO 2-Al 2O 3. The deoxygenation extent for Pt/CeO 2-ZrOO 2-Al 2O 3 was 48.4% and 14.5% higher than that for Pt/ZrO2O 2-Al 2O 3 and Pt/CeOO 2-Al 2O 3, respectively.« less

Microwave synthesis of pure and doped cerium (IV) oxide (CeO2) nanoparticles for methylene blue degradation.

PubMed

El Rouby, W M A; Farghali, A A; Hamdedein, A

2016-11-01

Cerium (IV) oxide (CeO 2 ), samarium (Sm) and gadolinium (Gd) doped CeO 2 nanoparticles were prepared using microwave technique. The effect of microwave irradiation time, microwave power and pH of the starting solution on the structure and crystallite size were investigated. The prepared nanoparticles were characterized using X-ray diffraction, FT-Raman spectroscopy, and transmission electron microscope. The photocatalytic activity of the as-prepared CeO 2 , Sm and Gd doped CeO 2 toward degradation of methylene blue (MB) dye was investigated under UV light irradiation. The effect of pH, the amount of catalyst and the dye concentration on the degradation extent were studied. The photocatalytic activity of CeO 2 was kinetically enhanced by trivalent cation (Gd and Sm) doping. The results revealed that Gd doped CeO 2 nanoparticles exhibit the best catalytic degradation activity on MB under UV irradiation. For clarifying the environmental safety of the by products produced from the degradation process, the pathways of MB degradation were followed using liquid chromatography/mass spectroscopy (LC/MS). The total organic carbon content measurements confirmed the results obtained by LC/MS. Compared to the same nanoparticles prepared by another method, it was found that Gd doped CeO 2 prepared by hydrothermal process was able to mineralize MB dye completely under UV light irradiation.

Synthesis of novel CeO2-BiVO4/FAC composites with enhanced visible-light photocatalytic properties.

PubMed

Zhang, Jin; Wang, Bing; Li, Chuang; Cui, Hao; Zhai, Jianping; Li, Qin

2014-09-01

To utilize visible light more effectively in photocatalytic reactions, a fly ash cenosphere (FAC)-supported CeO2-BiVO4 (CeO2-BiVO4/FAC) composite photocatalyst was prepared by modified metalorganic decomposition and impregnation methods. The physical and photophysical properties of the composite have been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and UV-Visible diffuse reflectance spectra. The XRD patterns exhibited characteristic diffraction peaks of both BiVO4 and CeO2 crystalline phases. The XPS results showed that Ce was present as both Ce(4+) and Ce(3+) oxidation states in CeO2 and dispersed on the surface of BiVO4 to constitute a p-n heterojunction composite. The absorption threshold of the CeO2-BiVO4/FAC composite shifted to a longer wavelength in the UV-Vis absorption spectrum compared to the pure CeO2 and pure BiVO4. The composites exhibited enhanced photocatalytic activity for Methylene Blue (MB) degradation under visible light irradiation. It was found that the 7.5wt.% CeO2-BiVO4/FAC composite showed the highest photocatalytic activity for MB dye wastewater treatment. Copyright © 2014. Published by Elsevier B.V.

Influence of CeO2 addition on the preparation of foamed glass-ceramics from high-titanium blast furnace slag

NASA Astrophysics Data System (ADS)

Zhou, Hong-ling; Feng, Ke-qin; Chen, Chang-hong; Yan, Zi-di

2018-06-01

Foamed glass-ceramics doped with cerium oxide (CeO2) were successfully prepared from high-titanium blast furnace slag by one-step sintering. The influence of CeO2 addition (1.5wt%-3.5wt%) on the crystalline phases, microstructure, and properties of foamed glass-ceramics was studied. Results show that CeO2 improves the stability of the glass phase and changes the two-dimensional crystallization mechanism into three-dimensional one. XRD analysis indicates the presence of Ca(Mg, Fe)Si2O6 and Ca(Ti, Mg, Al)(Si, Al)2O6 in all sintered samples. Added with CeO2, TiCeO4 precipitates, and crystallinity increases, leading to increased thickness of pore walls and uniform pores. The comprehensive properties of foamed glass-ceramics are better than that of samples without CeO2. In particular, the sample added with a suitable amount of CeO2 (2.5wt%) exhibits bulk density that is similar to and compressive strength (14.9 MPa) that is more than twice of foamed glass-ceramics without CeO2.

The Live In-Class CEO Intervention: A Capstone Experiential Technique for Leadership Development

ERIC Educational Resources Information Center

Rashford, Nicholas S.; de Figueiredo, Joao Neiva

2011-01-01

This article describes a pedagogical technique that has been used successfully for more than 35 years in business education, primarily as a capstone experience in MBA and Executive MBA programs: the live in-class CEO intervention method. This method consists of a CEO bringing to the classroom a strategic issue that she or he is currently…

Non-Gaussian operations on bosonic modes of light: Photon-added Gaussian channels

NASA Astrophysics Data System (ADS)

Sabapathy, Krishna Kumar; Winter, Andreas

2017-06-01

We present a framework for studying bosonic non-Gaussian channels of continuous-variable systems. Our emphasis is on a class of channels that we call photon-added Gaussian channels, which are experimentally viable with current quantum-optical technologies. A strong motivation for considering these channels is the fact that it is compulsory to go beyond the Gaussian domain for numerous tasks in continuous-variable quantum information processing such as entanglement distillation from Gaussian states and universal quantum computation. The single-mode photon-added channels we consider are obtained by using two-mode beam splitters and squeezing operators with photon addition applied to the ancilla ports giving rise to families of non-Gaussian channels. For each such channel, we derive its operator-sum representation, indispensable in the present context. We observe that these channels are Fock preserving (coherence nongenerating). We then report two examples of activation using our scheme of photon addition, that of quantum-optical nonclassicality at outputs of channels that would otherwise output only classical states and of both the quantum and private communication capacities, hinting at far-reaching applications for quantum-optical communication. Further, we see that noisy Gaussian channels can be expressed as a convex mixture of these non-Gaussian channels. We also present other physical and information-theoretic properties of these channels.

Applying the J-optimal channelized quadratic observer to SPECT myocardial perfusion defect detection

NASA Astrophysics Data System (ADS)

Kupinski, Meredith K.; Clarkson, Eric; Ghaly, Michael; Frey, Eric C.

2016-03-01

To evaluate performance on a perfusion defect detection task from 540 image pairs of myocardial perfusion SPECT image data we apply the J-optimal channelized quadratic observer (J-CQO). We compare AUC values of the linear Hotelling observer and J-CQO when the defect location is fixed and when it occurs in one of two locations. As expected, when the location is fixed a single channels maximizes AUC; location variability requires multiple channels to maximize the AUC. The AUC is estimated from both the projection data and reconstructed images. J-CQO is quadratic since it uses the first- and second- order statistics of the image data from both classes. The linear data reduction by the channels is described by an L x M channel matrix and in prior work we introduced an iterative gradient-based method for calculating the channel matrix. The dimensionality reduction from M measurements to L channels yields better estimates of these sample statistics from smaller sample sizes, and since the channelized covariance matrix is L x L instead of M x M, the matrix inverse is easier to compute. The novelty of our approach is the use of Jeffrey's divergence (J) as the figure of merit (FOM) for optimizing the channel matrix. We previously showed that the J-optimal channels are also the optimum channels for the AUC and the Bhattacharyya distance when the channel outputs are Gaussian distributed with equal means. This work evaluates the use of J as a surrogate FOM (SFOM) for AUC when these statistical conditions are not satisfied.

Gaussian-input Gaussian mixture model for representing density maps and atomic models.

PubMed

Kawabata, Takeshi

2018-07-01

A new Gaussian mixture model (GMM) has been developed for better representations of both atomic models and electron microscopy 3D density maps. The standard GMM algorithm employs an EM algorithm to determine the parameters. It accepted a set of 3D points with weights, corresponding to voxel or atomic centers. Although the standard algorithm worked reasonably well; however, it had three problems. First, it ignored the size (voxel width or atomic radius) of the input, and thus it could lead to a GMM with a smaller spread than the input. Second, the algorithm had a singularity problem, as it sometimes stopped the iterative procedure due to a Gaussian function with almost zero variance. Third, a map with a large number of voxels required a long computation time for conversion to a GMM. To solve these problems, we have introduced a Gaussian-input GMM algorithm, which considers the input atoms or voxels as a set of Gaussian functions. The standard EM algorithm of GMM was extended to optimize the new GMM. The new GMM has identical radius of gyration to the input, and does not suddenly stop due to the singularity problem. For fast computation, we have introduced a down-sampled Gaussian functions (DSG) by merging neighboring voxels into an anisotropic Gaussian function. It provides a GMM with thousands of Gaussian functions in a short computation time. We also have introduced a DSG-input GMM: the Gaussian-input GMM with the DSG as the input. This new algorithm is much faster than the standard algorithm. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Synthesis of feather-like CeO2 microstructures and enzymatic electrochemical catalysis for trichloroacetic acid

NASA Astrophysics Data System (ADS)

Xiao, Xin; Zhang, Dong En; Zhang, Fan; Gong, Jun Yan; Zhang, Xiao Bo; Wang, Yi Hui; Ma, Juan Juan; Tong, Zhi Wei

Novel feather-like CeO2 microstructures were achieved by a thermal decomposition approach of Ce(OH)CO3 precursor. The Ce(OH)CO3 was obtained from a solvothermal method employing Ce(NO3)3.6H2O with C6H12N4 and C16H33(CH3)3NBr (CTAB) at 190∘C in a water-PEG-200 mixed solution. The feather-like CeO2 dendrite was obtained by thermal conversion of the feather-like Ce(OH)CO3 at 650∘C in air. A reasonable growth mechanism was proposed with the soft-template effect of PEG-200. The electrochemical behavior and enzyme activity of myoglobin (Mb) immobilized on CeO2-Nafion modified glassy carbon electrode (GCE) are demonstrated by cyclic voltammetric measurements. The results indicate that CeO2 can obviously promote the direct electron transfer between the Mb redox centers and the electrode. The Mb on CeO2-Nafion behaves as an elegant performance on the electrochemical reduction of trichloroacetic acid (TCA) from 0.32μM to 2.28μM. The detection limit is estimated to be 0.08μM.

Regulating the active species of Ni(OH)2 using CeO2: 3D CeO2/Ni(OH)2/carbon foam as an efficient electrode for the oxygen evolution reaction.

PubMed

Liu, Zhengqing; Li, Na; Zhao, Hongyang; Zhang, Yi; Huang, Yunhui; Yin, Zongyou; Du, Yaping

2017-04-01

Three dimensional (3D) N, O and S doped carbon foam (NOSCF) is prepared as a substrate for in situ vertically grown Ni(OH) 2 nanosheets. As designed Ni(OH) 2 /NOSCF possesses strong electrostatic interactions with OH - ions due to many C 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 1111111111111111111111111111111111 1111111111111111111111111111111111 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 0000000000000000000000000000000000 O groups existing in NOSCF, which can facilitate the formation of crucial NiOOH intermediates during the OER process. CeO 2 nanoparticles (NPs) of ∼3.3 nm in size are decorated on Ni(OH) 2 nanosheets to design a highly efficient CeO 2 /Ni(OH) 2 /NOSCF electrocatalyst for the oxygen evolution reaction (OER). The CeO 2 NP decorated Ni(OH) 2 /NOSCF not only exhibits a remarkably improved OER performance with an onset potential of 240 mV, outperforming most reported non-noble metal based OER electrocatalysts, but also possesses a small Tafel slope of 57 mV dec -1 and

Cell uptake, intracellular distribution, fate and reactive oxygen species generation of polymer brush engineered CeO2-x NPs

NASA Astrophysics Data System (ADS)

Qiu, Yuan; Rojas, Elena; Murray, Richard A.; Irigoyen, Joseba; Gregurec, Danijela; Castro-Hartmann, Pablo; Fledderman, Jana; Estrela-Lopis, Irina; Donath, Edwin; Moya, Sergio E.

2015-04-01

Cerium Oxide nanoparticles (CeO2-x NPs) are modified with polymer brushes of negatively charged poly (3-sulfopropylmethacrylate) (PSPM) and positively charged poly (2-(methacryloyloxy)ethyl-trimethylammonium chloride) (PMETAC) by Atom Transfer Radical Polymerisation (ATRP). CeO2-x NPs are fluorescently labelled by covalently attaching Alexa Fluor® 488/Fluorescein isothiocyanate to the NP surface prior to polymerisation. Cell uptake, intracellular distribution and the impact on the generation of intracellular Reactive Oxygen Species (ROS) with respect to CeO2-x NPs are studied by means of Raman Confocal Microscopy (CRM), Transmission Electron Microscopy (TEM) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). PSPM and PMETAC coated CeO2-x NPs show slower and less uptake compared to uncoated Brush modified NPs display a higher degree of co-localisation with cell endosomes and lysosomes after 24 h of incubation. They also show higher co-localisation with lipid bodies when compared to unmodified CeO2-x NPs. The brush coating does not prevent CeO2-x NPs from displaying antioxidant properties.Cerium Oxide nanoparticles (CeO2-x NPs) are modified with polymer brushes of negatively charged poly (3-sulfopropylmethacrylate) (PSPM) and positively charged poly (2-(methacryloyloxy)ethyl-trimethylammonium chloride) (PMETAC) by Atom Transfer Radical Polymerisation (ATRP). CeO2-x NPs are fluorescently labelled by covalently attaching Alexa Fluor® 488/Fluorescein isothiocyanate to the NP surface prior to polymerisation. Cell uptake, intracellular distribution and the impact on the generation of intracellular Reactive Oxygen Species (ROS) with respect to CeO2-x NPs are studied by means of Raman Confocal Microscopy (CRM), Transmission Electron Microscopy (TEM) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). PSPM and PMETAC coated CeO2-x NPs show slower and less uptake compared to uncoated Brush modified NPs display a higher degree of co-localisation with cell

Decay rates of Gaussian-type I-balls and Bose-enhancement effects in 3+1 dimensions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawasaki, Masahiro; Yamada, Masaki; ICRR, University of Tokyo, Kashiwa, 277-8582

2014-02-03

I-balls/oscillons are long-lived spatially localized lumps of a scalar field which may be formed after inflation. In the scalar field theory with monomial potential nearly and shallower than quadratic, which is motivated by chaotic inflationary models and supersymmetric theories, the scalar field configuration of I-balls is approximately Gaussian. If the I-ball interacts with another scalar field, the I-ball eventually decays into radiation. Recently, it was pointed out that the decay rate of I-balls increases exponentially by the effects of Bose enhancement under some conditions and a non-perturbative method to compute the exponential growth rate has been derived. In this paper,more » we apply the method to the Gaussian-type I-ball in 3+1 dimensions assuming spherical symmetry, and calculate the partial decay rates into partial waves, labelled by the angular momentum of daughter particles. We reveal the conditions that the I-ball decays exponentially, which are found to depend on the mass and angular momentum of daughter particles and also be affected by the quantum uncertainty in the momentum of daughter particles.« less

Decay rates of Gaussian-type I-balls and Bose-enhancement effects in 3+1 dimensions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawasaki, Masahiro; Yamada, Masaki, E-mail: kawasaki@icrr.u-tokyo.ac.jp, E-mail: yamadam@icrr.u-tokyo.ac.jp

2014-02-01

I-balls/oscillons are long-lived spatially localized lumps of a scalar field which may be formed after inflation. In the scalar field theory with monomial potential nearly and shallower than quadratic, which is motivated by chaotic inflationary models and supersymmetric theories, the scalar field configuration of I-balls is approximately Gaussian. If the I-ball interacts with another scalar field, the I-ball eventually decays into radiation. Recently, it was pointed out that the decay rate of I-balls increases exponentially by the effects of Bose enhancement under some conditions and a non-perturbative method to compute the exponential growth rate has been derived. In this paper,more » we apply the method to the Gaussian-type I-ball in 3+1 dimensions assuming spherical symmetry, and calculate the partial decay rates into partial waves, labelled by the angular momentum of daughter particles. We reveal the conditions that the I-ball decays exponentially, which are found to depend on the mass and angular momentum of daughter particles and also be affected by the quantum uncertainty in the momentum of daughter particles.« less

Hollow vortex Gaussian beams

NASA Astrophysics Data System (ADS)

Zhou, GuoQuan; Cai, YangJian; Dai, ChaoQing

2013-05-01

A kind of hollow vortex Gaussian beam is introduced. Based on the Collins integral, an analytical propagation formula of a hollow vortex Gaussian beam through a paraxial ABCD optical system is derived. Due to the special distribution of the optical field, which is caused by the initial vortex phase, the dark region of a hollow vortex Gaussian beam will not disappear upon propagation. The analytical expressions for the beam propagation factor, the kurtosis parameter, and the orbital angular momentum density of a hollow vortex Gaussian beam passing through a paraxial ABCD optical system are also derived, respectively. The beam propagation factor is determined by the beam order and the topological charge. The kurtosis parameter and the orbital angular momentum density depend on beam order n, topological charge m, parameter γ, and transfer matrix elements A and D. As a numerical example, the propagation properties of a hollow vortex Gaussian beam in free space are demonstrated. The hollow vortex Gaussian beam has eminent propagation stability and has crucial application prospects in optical micromanipulation.

CEO Business Education and Firm Financial Performance: A Case for Humility Rather than Hubris

ERIC Educational Resources Information Center

Lindorff, Margaret; Jonson, Elizabeth Prior

2013-01-01

Purpose: The purpose of this paper is to examine the relationship between CEO business education and firm financial performance. Design/methodology/approach: An analysis of the relationship between three-year and five-year shareholder return as measured by dividend and change in share price and CEO educational qualification was performed.…

Diversity begets diversity? The effects of board composition on the appointment and success of women CEOs.

PubMed

Cook, Alison; Glass, Christy

2015-09-01

Previous research on the effects of leadership diversity on firm outcomes has produced inconsistent and inconclusive findings. While some scholars argue that diversity increases organizational equity and enhances performance, others argue that diversity increases conflict, reduces cooperation and harms performance. This study tests the impact of a variety of compositional factors on firm outcomes. Specifically, we analyze whether and how board composition affects the advancement and mobility of women CEOs and firm performance. Our analysis relies on a unique data set of all Chief Executive Officers (CEOs) and Board of Directors (BODs) in Fortune 500 companies over a ten-year period. We find a marginally significant positive relationship between board diversity and the likelihood of a woman being appointed CEO. We further find that board diversity significantly and positively influences the post-promotion success of women CEOs. Our findings suggest that board composition is critical for the appointment and success of women CEOs, and increasing board diversity should be central to any organizational diversity efforts. Copyright © 2015 Elsevier Inc. All rights reserved.

The Interaction of Carbon Monoxide with Rhodium on Potassium-Modified CeO 2(111)

DOE PAGES

Mullins, David R.

2016-02-03

The adsorption and reactions of CO adsorbed on Rh particles deposited on K-covered CeO 2(111) were studied by temperature programmed desorption and photoelectron spectroscopy. K deposited on CeO 2(111) forms a KO X over-layer by extracting O from the ceria and partially reducing some of the Ce 4+ to Ce 3+. CO does not adsorb on the KO X / CeO 2-X(111) surface in the absence of Rh particles. CO adsorbed on Rh / K / CeO 2(111) adsorbs molecularly on the Rh at 200 K. As the surface is heated the CO spills-over and reacts with the KOX tomore » form carbonate. The carbonate decomposes at elevated temperature to produce CO and CO 2. The carbonate stabilizes the KO X so that K desorbs at a higher temperature than it would in the absence of CO. When the Rh and K deposition are reversed so that K is deposited on both the Rh and the CeO 2(111), CO adsorbs as CO 2- at 200 K. The CO 2- decomposes below 350 K to produce gas phase CO and adsorbed CO3 2- and CO. The CO is stabilized by the K on the Rh and desorbs above 540 K. The carbonate decomposes into gas phase CO and CO 2.« less

Different heat treatment of CeO2 nanoparticle composited with ZnO to enhance photocatalytic performance

NASA Astrophysics Data System (ADS)

Taufik, A.; Shabrany, H.; Saleh, R.

2017-04-01

In this study, ZnO/CeO2 nanocomposites were prepared with four variations of the molar ratio of ZnO to CeO2 nanoparticles. Both ZnO and CeO2 nanoparticles were synthesized using the sol-gel method at low temperature, followed by different heat treatments for CeO2 nanoparticles. Thermal phase transformation studies of the CeO2 nanoparticles were observed at annealing temperatures of 400-800°C. The complete crystalline structure of CeO2 nanoparticles was obtained at an annealing temperature of 800°C. The structural and optical properties of all samples were observed using several characterization techniques, such as X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy, and Brunauer, Emmett, and Teller (BET) surface area analysis. The structural characterization results revealed that the prepared CeO2 nanoparticles were quite crystalline, with a cubic structure. The photocatalytic activities of all samples were tested under visible irradiation. The obtained results showed that ZnO/CeO2 nanocomposites with a molar ratio 1:0.3 exhibited the highest photocatalytic activity. Further understanding of the role of primary active species underlying the reaction mechanism involved in photocatalytic activity were carried out in controlled experiments by adding several scavengers. The detailed mechanism and its correlation with the properties of ZnO/CeO2 nanocomposites were discuss.

Confined NaAlH4 nanoparticles inside CeO2 hollow nanotubes towards enhanced hydrogen storage.

PubMed

Gao, Qili; Xia, Guanglin; Yu, Xuebin

2017-10-05

NaAlH 4 has been widely regarded as a potential hydrogen storage material due to its favorable thermodynamics and high energy density. The high activation energy barrier and high dehydrogenation temperature, however, significantly hinder its practical application. In this paper, CeO 2 hollow nanotubes (HNTs) prepared by a simple electrospinning technique are adopted as functional scaffolds to support NaAlH 4 nanoparticles (NPs) towards advanced hydrogen storage performance. The nanoconfined NaAlH 4 inside CeO 2 HNTs, synthesized via the infiltration of molten NaAlH 4 into the CeO 2 HNTs under high hydrogen pressure, exhibited significantly improved dehydrogenation properties compared with both bulk and ball-milled CeO 2 HNTs-catalyzed NaAlH 4 . The onset dehydrogenation temperature of the NaAlH 4 @CeO 2 composite was reduced to below 100 °C, with only one main dehydrogenation peak appearing at 130 °C, which is 120 °C and 50 °C lower than for its bulk counterpart and for the ball-milled CeO 2 HNTs-catalyzed NaAlH 4 , respectively. Moreover, ∼5.09 wt% hydrogen could be released within 30 min at 180 °C, while only 1.6 wt% hydrogen was desorbed from the ball-milled NaAlH 4 under the same conditions. This significant improvement is mainly attributed to the synergistic effects contributed by the CeO 2 HNTs, which could act as not only a structural scaffold to fabricate and confine the NaAlH 4 NPs, but also as an effective catalyst to enhance the hydrogen storage performance of NaAlH 4 .

76 FR 12337 - Request for Applicants for Appointment to the United States-Brazil CEO Forum

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-07

... to the United States- Brazil CEO Forum AGENCY: International Trade Administration, Department of Commerce. ACTION: Notice. SUMMARY: In March 2007, the Governments of the United States and Brazil established the U.S.-Brazil CEO Forum. This notice announces membership opportunities for appointment as...

CEO must have authority to coordinate governance, management, medical staff.

PubMed

Johnson, R L

1984-04-01

As hospitals attempt to survive in today's new competitive environment, they will find that the traditional organizational structure does not work. This structure can be characterized as a three-legged stool. Governance, management, and medical staff existed in relative harmony, with each able to attend to its own distinct, separate responsibilities. The medical staff regulated itself, the governing board had no serious difficulties in coping with the institution's finances, and the CEO was concerned solely with the physical plant and hospital personnel. In a riskless economic environment, this three-legged stool could remain stable. In the coming years,however, a hospital will need a clear-cut, identifiable leader if it is to survive. To centralize authority primarily in the CEO's hands will be a difficult step for nonprofit hospitals, particularly those sponsored by religious institutions, because of their tradition of operating much as a charitable social agency rather than a business. But this step must be taken, even to the extent of naming the CEO as chairman of the board, for a leader is required who has the authority to make quick decisions in the competitive marketplace. Timeliness is of strategic importance in such an environment, and governing boards increasingly will find it impossible to make timely decisions on a collective basis. Moreover, CEOs will have to coordinate the activities of management, medical staff, and the governing board. They will need to play a strong role in ensuring that target levels in DRG costs are met, and they will need the authority to mediate in issues in which the hospital's economic interests are pitted against physicians'.(ABSTRACT TRUNCATED AT 250 WORDS)

An Algebraic Approach for Solving Quadratic Inequalities

ERIC Educational Resources Information Center

Mahmood, Munir; Al-Mirbati, Rudaina

2017-01-01

In recent years most text books utilise either the sign chart or graphing functions in order to solve a quadratic inequality of the form ax[superscript 2] + bx + c < 0 This article demonstrates an algebraic approach to solve the above inequality. To solve a quadratic inequality in the form of ax[superscript 2] + bx + c < 0 or in the…

Investigation on charge transfer bands of Ce 4+ in Sr 2CeO 4 blue phosphor

NASA Astrophysics Data System (ADS)

Li, Ling; Zhou, Shihong; Zhang, Siyuan

2008-03-01

Bulk and nano-materials Sr2CeO4 were prepared by solid-state reaction and sol-gel technique, respectively. Photoluminescence shows that luminescence has the characteristic of a ligand-to-metal charge transfer (CT) emission. Compared with bulk Sr2CeO4, the nano-material exhibits stronger emission intensity, longer decay time, and higher CT excitation energy. Three CT excitation peaks were observed in both bulk and nano samples. Based on the theoretical calculations of the average energy gap of the chemical bond using the dielectric theory of complex crystal, the highest and the lowest energy CT bands were assigned to the transitions O1 → Ce4+ and O2 → Ce4+, respectively. The middle bands were due to the superposition of the transitions Ce-O1 and Ce-O2.

A facile method of fabricating mechanical durable anti-icing coatings based on CeO2 microparticles

NASA Astrophysics Data System (ADS)

Wang, Pengren; Peng, Chaoyi; Wu, Binrui; Yuan, Zhiqing; Yang, Fubiao; Zeng, Jingcheng

2015-07-01

Compromising between hydrophobicity and mechanical durability may be a feasible approach to fabricating usable anti-icing coatings. This work improves the contact angle of current commercial anti-icing coatings applied to wind turbine blades dramatically and keeps relatively high mechanical durability. CeO2 microparticles and diluent were mixed with fluorocarbon resin to fabricate high hydrophobic coatings on the glass fiber reinforced epoxy composite substrates. The proportion of CeO2 microparticles and diluent influences the contact angles significantly. The optimum mass ratio of fluorocarbon resin to CeO2 microparticles to diluent is 1:1.5:1, which leads to the highest contact angle close to 140°. The microscopy analysis shows that the CeO2 microparticles form nano/microscale hierarchical structure on the surface of the coatings.

Fabrication of CeO2–MOx (M = Cu, Co, Ni) composite yolk–shell nanospheres with enhanced catalytic properties for CO oxidation

PubMed Central

Shi, Jingjing; Cao, Hongxia; Wang, Ruiyu

2017-01-01

CeO2–MOx (M = Cu, Co, Ni) composite yolk–shell nanospheres with uniform size were fabricated by a general wet-chemical approach. It involved a non-equilibrium heat-treatment of Ce coordination polymer colloidal spheres (Ce-CPCSs) with a proper heating rate to produce CeO2 yolk–shell nanospheres, followed by a solvothermal treatment of as-synthesized CeO2 with M(CH3COO)2 in ethanol solution. During the solvothermal process, highly dispersed MOx species were decorated on the surface of CeO2 yolk–shell nanospheres to form CeO2–MOx composites. As a CO oxidation catalyst, the CeO2–MOx composite yolk–shell nanospheres showed strikingly higher catalytic activity than naked CeO2 due to the strong synergistic interaction at the interface sites between MOx and CeO2. Cycling tests demonstrate the good cycle stability of these yolk–shell nanospheres. The initial concentration of M(CH3COO)2·xH2O in the synthesis process played a significant role in catalytic performance for CO oxidation. Impressively, complete CO conversion as reached at a relatively low temperature of 145 °C over the CeO2–CuOx-2 sample. Furthermore, the CeO2–CuOx catalyst is more active than the CeO2–CoOx and CeO2–NiO catalysts, indicating that the catalytic activity is correlates with the metal oxide. Additionally, this versatile synthesis approach can be expected to create other ceria-based composite oxide systems with various structures for a broad range of technical applications. PMID:29234577

78 FR 32239 - Request for Applicants for Appointment to the United States-Brazil CEO Forum

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-29

... to the United States- Brazil CEO Forum AGENCY: International Trade Administration, Department of Commerce. ACTION: Notice. SUMMARY: In March 2007, the Governments of the United States and Brazil established the U.S.-Brazil CEO Forum. This notice announces membership opportunities for up to twelve...

Quantum entanglement beyond Gaussian criteria.

PubMed

Gomes, R M; Salles, A; Toscano, F; Souto Ribeiro, P H; Walborn, S P

2009-12-22

Most of the attention given to continuous variable systems for quantum information processing has traditionally been focused on Gaussian states. However, non-Gaussianity is an essential requirement for universal quantum computation and entanglement distillation, and can improve the efficiency of other quantum information tasks. Here we report the experimental observation of genuine non-Gaussian entanglement using spatially entangled photon pairs. The quantum correlations are invisible to all second-order tests, which identify only Gaussian entanglement, and are revealed only under application of a higher-order entanglement criterion. Thus, the photons exhibit a variety of entanglement that cannot be reproduced by Gaussian states.

A comparative study of CeO2-Al2O3 support prepared with different methods and its application on MoO3/CeO2-Al2O3 catalyst for sulfur-resistant methanation

NASA Astrophysics Data System (ADS)

Jiang, Minhong; Wang, Baowei; Yao, Yuqin; Li, Zhenhua; Ma, Xinbin; Qin, Shaodong; Sun, Qi

2013-11-01

The CeO2-Al2O3 supports prepared with impregnation (IM), deposition precipitation (DP), and solution combustion (SC) methods for MoO3/CeO2-Al2O3 catalyst were investigated in the sulfur-resistant methanation. The supports and catalysts were characterized by N2-physisorption, transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy (RS), and temperature-programmed reduction (TPR). The N2-physisorption results indicated that the DP method was favorable for obtaining better textural properties. The TEM and RS results suggested that there is a CeO2 layer on the surface of the support prepared with DP method. This CeO2 layer not only prevented the interaction between MoO3 and γ-Al2O3 to form Al2(MoO4)3 species, but also improved the dispersion of MoO3 in the catalyst. Accordingly, the catalysts whose supports were prepared with DP method exhibited the best catalytic activity. The catalysts whose supports were prepared with SC method had the worst catalytic activity. This was caused by the formation of Al2(MoO4)3 and crystalline MoO3. Additionally, the CeO2 layer resulted in the instability of catalysts in reaction process. The increasing of calcination temperature of supports reduced the catalytic activity of all catalysts. The decrease extent of the catalysts whose supports were prepared with DP method was the lowest as the CeO2 layer prevented the interaction between MoO3 and γ-Al2O3.

Investigation of trimethylacetic acid adsorption on stoichiometric and oxygen-deficient CeO 2 (111) surfaces

DOE PAGES

Sanghavi, Shail; Wang, Weina; Nandasiri, Manjula I.; ...

2016-05-12

We studied the interactions between the carboxylate anchoring group from trimethylacetic acid (TMAA) and CeO 2(111) surfaces as a function of oxygen stoichiometry using in situ X-ray photoelectron spectroscopy (XPS). The stoichiometric CeO 2(111) surface was obtained by annealing the thin film under 2.0 × 10 –5 Torr of oxygen at ~550 °C for 30 min. In order to reduce the CeO 2(111) surface, the thin film was annealed under ~5.0 × 10 –10 Torr vacuum conditions at 550 °C, 650 °C, 750 °C and 850 °C for 30 min to progressively increase the oxygen defect concentration on the surface.more » The saturated TMAA coverage on the CeO 2(111) surface determined from XPS elemental composition is found to increase with increasing oxygen defect concentration. This is attributed to the increase of under-coordinated cerium sites on the surface with the increase in the oxygen defect concentrations. Furthermore, XPS results were in agreement with periodic density functional theory (DFT) calculations and indicate a stronger binding between the carboxylate group from TMAA and the oxygen deficient CeO 2–δ(111) surface through dissociative adsorption.« less

Study of the growth of CeO2 nanoparticles onto titanate nanotubes

NASA Astrophysics Data System (ADS)

Marques, Thalles M. F.; Ferreira, Odair P.; da Costa, Jose A. P.; Fujisawa, Kazunori; Terrones, Mauricio; Viana, Bartolomeu C.

2015-12-01

We report the study of the growth of CeO2 nanoparticles on the external walls and Ce4+ intercalation within the titanate nanotubes. The materials were fully characterized by multiple techniques, such as: Raman spectroscopy, infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The ion exchange processes in the titanate nanotubes were carried out using different concentrations of Ce4+ in aqueous solution. Our results indicate that the growth of CeO2 nanoparticles grown mediated by the hydrolysis in the colloidal species of Ce and the attachment onto the titanate nanotubes happened and get it strongly anchored to the titanate nanotube surface by a simple electrostatic interaction between the nanoparticles and titanate nanotubes, which can explain the small size and even distribution of nanoparticles on titanate supports. It was demonstrated that it is possible to control the amount and size of CeO2 nanoparticles onto the nanotube surface, the species of the Ce ions intercalated between the layers of titanate nanotubes, and the materials could be tuned for using in specific catalysis in according with the amount of CeO2 nanoparticles, their oxygen vacancies/defects and the types of Ce species (Ce4+ or Ce3+) present into the nanotubes.

The role of facial appearance on CEO selection after firm misconduct.

PubMed

Gomulya, David; Wong, Elaine M; Ormiston, Margaret E; Boeker, Warren

2017-04-01

[Correction Notice: An Erratum for this article was reported in Vol 102(4) of Journal of Applied Psychology (see record 2017-10684-001). The wrong figure files were used. All versions of this article have been corrected.] We investigate a particular aspect of CEO successor trustworthiness that may be critically important after a firm has engaged in financial misconduct. Specifically, drawing on prior research that suggests that facial appearance is one critical way in which trustworthiness is signaled, we argue that leaders who convey integrity, a component of trustworthiness, will be more likely to be selected as successors after financial restatement. We predict that such appointments garner more positive reactions by external observers such as investment analysts and the media because these CEOs are perceived as having greater integrity. In an archival study of firms that have announced financial restatements, we find support for our predictions. These findings have implications for research on CEO succession, leadership selection, facial appearance, and firm misconduct. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Consensus on the leadership of hospital CEOs and its impact on the participation of physicians in improvement projects.

PubMed

Dückers, Michel L A; Stegeman, Inge; Spreeuwenberg, Peter; Wagner, Cordula; Sanders, Karin; Groenewegen, Peter P

2009-08-01

The success of a Dutch program to disseminate quality improvement projects depends on the participation of physicians working in program hospitals. The leadership of hospital executives (CEOs) is considered an important explanation. This study aims to determine whether the relation, between the extent to which physicians notice their CEOs stimulate improvement initiatives and the number of projects joined by physicians, is moderated by the consensus among physicians working in the same hospital. Multilevel analyses are applied on data of 286 physicians from eight hospitals to: (1) estimate whether participation depends on noticing if CEOs stimulate improvement, (2) test if an individual's participation differs when more colleagues have the same opinion (effect modification). Significant moderator effects are found. The participation of physicians, noticing that CEOs stimulate improvement is higher when more colleagues share this opinion. For physicians not knowing whether improvement is encouraged, higher consensus coincides with lower participation. Project involvement of physicians depends on their consensus about encouragement by CEOs. This confirms the importance of strategic leaders in dissemination programs. Further research is recommended into causes of CEO leadership visibility and methods to strengthen leadership climate.

Nanocrystalline CeO2-δ coated β-MnO2 nanorods with enhanced oxygen transfer property

NASA Astrophysics Data System (ADS)

Huang, Xiubing; Zhao, Guixia; Chang, Yueqi; Wang, Ge; Irvine, John T. S.

2018-05-01

In this research, β-MnO2 nanorods were synthesized by a hydrothermal method, followed by a facile precipitation method to obtain nanocrystalline CeO2-δ coated β-MnO2 nanorods. The as-prepared samples were characterized by XRD, HRTEM, FESEM, XPS and in-situ high-temperature XRD. The HRTEM results show that well dispersed CeO2-δ nanocrystals sized about 5 nm were coated on the surface of β-MnO2 nanorods. The oxygen storage and transfer property of as-synthesized materials were evaluated using TGA under various atmospheres (air, pure N2, and 5%H2/95%Ar). The TGA results indicate that CeO2-δ modification could favour the reduction of Mn4+ to Mn3+ and/or Mn2+ at lower temperature as compared with pure β-MnO2 nanorods and the physically mixed CeO2-δ-β-MnO2 under low oxygen partial pressure conditions (i.e., pure N2, 5%H2/95%Ar). Specifically, CeO2-δ@β-MnO2 sample can exhibit 7.5 wt% weight loss between 100 and 400 °C under flowing N2 and 11.4 wt% weight loss between 100 and 350 °C under flowing 5%H2/95%Ar. During the reduction process under pure N2 or 5%H2/95%Ar condition, the oxygen ions in β-MnO2 nanorods are expected to be released to the surroundings in the form of O2 or H2O with the coated CeO2-δ nanocrystals acting as mediator as inferred from the synergistic effect between the well-interacted CeO2-δ nanocrystals and β-MnO2 nanorods.

Truncated Gaussians as tolerance sets

NASA Technical Reports Server (NTRS)

Cozman, Fabio; Krotkov, Eric

1994-01-01

This work focuses on the use of truncated Gaussian distributions as models for bounded data measurements that are constrained to appear between fixed limits. The authors prove that the truncated Gaussian can be viewed as a maximum entropy distribution for truncated bounded data, when mean and covariance are given. The characteristic function for the truncated Gaussian is presented; from this, algorithms are derived for calculation of mean, variance, summation, application of Bayes rule and filtering with truncated Gaussians. As an example of the power of their methods, a derivation of the disparity constraint (used in computer vision) from their models is described. The authors' approach complements results in Statistics, but their proposal is not only to use the truncated Gaussian as a model for selected data; they propose to model measurements as fundamentally in terms of truncated Gaussians.

A Facile Method for Loading CeO2 Nanoparticles on Anodic TiO2 Nanotube Arrays.

PubMed

Liao, Yulong; Yuan, Botao; Zhang, Dainan; Wang, Xiaoyi; Li, Yuanxun; Wen, Qiye; Zhang, Huaiwu; Zhong, Zhiyong

2018-04-03

In this paper, a facile method was proposed to load CeO 2 nanoparticles (NPs) on anodic TiO 2 nanotube (NT) arrays, which leads to a formation of CeO 2 /TiO 2 heterojunctions. Highly ordered anatase phase TiO 2 NT arrays were fabricated by using anodic oxidation method, then these individual TiO 2 NTs were used as tiny "nano-containers" to load a small amount of Ce(NO 3 ) 3 solutions. The loaded anodic TiO 2 NTs were baked and heated to a high temperature of 450 °C, under which the Ce(NO 3 ) 3 would be thermally decomposed inside those nano-containers. After the thermal decomposition of Ce(NO 3 ) 3 , cubic crystal CeO 2 NPs were obtained and successfully loaded into the anodic TiO 2 NT arrays. The prepared CeO 2 /TiO 2 heterojunction structures were characterized by a variety of analytical technologies, including XRD, SEM, and Raman spectra. This study provides a facile approach to prepare CeO 2 /TiO 2 films, which could be very useful for environmental and energy-related areas.

Quantum entanglement beyond Gaussian criteria

PubMed Central

Gomes, R. M.; Salles, A.; Toscano, F.; Souto Ribeiro, P. H.; Walborn, S. P.

2009-01-01

Most of the attention given to continuous variable systems for quantum information processing has traditionally been focused on Gaussian states. However, non-Gaussianity is an essential requirement for universal quantum computation and entanglement distillation, and can improve the efficiency of other quantum information tasks. Here we report the experimental observation of genuine non-Gaussian entanglement using spatially entangled photon pairs. The quantum correlations are invisible to all second-order tests, which identify only Gaussian entanglement, and are revealed only under application of a higher-order entanglement criterion. Thus, the photons exhibit a variety of entanglement that cannot be reproduced by Gaussian states. PMID:19995963

The translocation and distribution of CeO2 nanoparticles in plants (Soybeans, Chili, Eggplant and Tomato)

NASA Astrophysics Data System (ADS)

Li, Teng; Dai, Yanhui

2018-02-01

Intensive production of CeO2 nanoparticles (NPs) would lead to their release into the environment. While their use in commercial goods is constantly increasing, location of NPs in plant is still poorly documented. In this study we determined the translocation of CeO2-NPs in four plants (Soybeans, Tomato, Chili and Eggplant) grown in natural conditions. The plants were digged out 1/4 roots into 2000 mg/L CeO2-NPs solution during the blossoming period. After being exposed for one month, the contents of Ce in plant tissues were measured by inductively coupled plasma mass spectrometry (ICP-MS). There was more Ce in the leaf of treated plants than in control plants. The contents of Ce in leaf tissues was different. This research offers vital information about the translocation and distribution of CeO2-NPs in higher plants.

Graphical Solution of the Monic Quadratic Equation with Complex Coefficients

ERIC Educational Resources Information Center

Laine, A. D.

2015-01-01

There are many geometrical approaches to the solution of the quadratic equation with real coefficients. In this article it is shown that the monic quadratic equation with complex coefficients can also be solved graphically, by the intersection of two hyperbolas; one hyperbola being derived from the real part of the quadratic equation and one from…

The CEOS Atmospheric Composition Constellation: Enhancing the Value of Space-Based Observations

NASA Technical Reports Server (NTRS)

Eckman, Richard; Zehner, Claus; Al-Saadi, Jay

2015-01-01

The Committee on Earth Observation Satellites (CEOS) coordinates civil space-borne observations of the Earth. Participating agencies strive to enhance international coordination and data exchange and to optimize societal benefit. In recent years, CEOS has collaborated closely with the Group on Earth Observations (GEO) in implementing the Global Earth Observing System of Systems (GEOSS) space-based objectives. The goal of the CEOS Atmospheric Composition Constellation (ACC) is to collect and deliver data to improve monitoring, assessment and predictive capabilities for changes in the ozone layer, air quality and climate forcing associated with changes in the environment through coordination of existing and future international space assets. A project to coordinate and enhance the science value of a future constellation of geostationary sensors measuring parameters relevant to air quality supports the forthcoming European Sentinel-4, Korean GEMS, and US TEMPO missions. Recommendations have been developed for harmonization to mutually improve data quality and facilitate widespread use of the data products.

Exceptional capability of nanosized CeO(2) materials to "dissolve" lanthanide oxides established by time-gated excitation and emission spectroscopy.

PubMed

Tiseanu, Carmen; Parvulescu, Vasile; Avram, Daniel; Cojocaru, Bogdan; Sanchez-Dominguez, Margarita

2014-05-28

The atomic scale homogeneity of Ce and Zr oxygen bonds represents the main reason for enhanced total oxygen storage capability of CeO2-ZrO2 (Ce/Zr = 1) as compared to that of CeO2. Here, we demonstrate that the addition of 10% Eu(3+) by wet impregnation on preformed nanosized CeO2-ZrO2 (Ce/Zr = 1) followed by calcination induces a remarkable homogeneity of 10% Eu(3+)-CeO2-ZrO2 solid solution. By use of time-resolved emission and excitation spectroscopies, the improvement of the nanoscale chemical and structural homogeneity of 10% Eu(3+)-CeO2-ZrO2 calcined at 1000 as compared to sample calcined at 750 °C is demonstrated. Based on the comparison of luminescence properties of 10% Eu(3+) impregnated on preformed nanosized CeO2-ZrO2 and CeO2, we also show that the presence of zirconium does not only preserve the ability of cerium oxide to "dissolve" lanthanide oxide, but also determines an important stabilization of defects (oxygen vacancies) generated upon Eu(3+) doping.

Unusual Phase Diagram of CeOs 4Sb 12

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, P. -C.; Goddard, P. A.; Maple, M. B.

2017-03-01

Filled skutterudite compounds, with the formula MT 4X 12, where M is an alkali metal, alkaline-earth, lanthanide, or actinide, T is Fe, Ru, or Os, and X is P, As, or Sb, display a wide variety of interesting phenomena caused by strong electron correlations [1]. Among these, the three compounds CeOs 4Sb 12, PrOs 4Sb 12, and NdOs 4Sb 12, formed by employing Periodic Table neighbors for M, span the range from an antiferromagnetic (AFM) semimetal (M = Ce) via a 1.85 K unconventional (quadrupolar-fluctuation mediated) superconductor (M = Pr) to a 1 K ferromagnet (FM; M = Nd). Inmore » the course of an extended study of these compounds, we uncovered an unusual phase diagram for CeOs 4Sb 12.« less

Magnetic ordered mesoporous Fe3O4/CeO2 composites with synergy of adsorption and Fenton catalysis

NASA Astrophysics Data System (ADS)

Li, Keyan; Zhao, Yongqin; Song, Chunshan; Guo, Xinwen

2017-12-01

Magnetic Fe3O4/CeO2 composites with highly ordered mesoporous structure and large surface area were synthesized by impregnation-calcination method, and the mesoporous CeO2 as support was synthesized via the hard template approach. The composition, morphology and physicochemical properties of the materials were characterized by XRD, SEM, TEM, XPS, Raman spectra and N2 adsorption/desorption analysis. The mesoporous Fe3O4/CeO2 composite played a dual-function role as both adsorbent and Fenton-like catalyst for removal of organic dye. The methylene blue (MB) removal efficiency of mesoporous Fe3O4/CeO2 was much higher than that of irregular porous Fe3O4/CeO2. The superior adsorption ability of mesoporous materials was attributed to the abundant oxygen vacancies on the surface of CeO2, high surface area and ordered mesoporous channels. The good oxidative degradation resulted from high Ce3+ content and the synergistic effect between Fe and Ce. The mesoporous Fe3O4/CeO2 composite presented low metal leaching (iron 0.22 mg L-1 and cerium 0.63 mg L-1), which could be ascribed to the strong metal-support interactions for dispersion and stabilization of Fe species. In addition, the composite can be easily separated from reaction solution with an external magnetic field due to its magnetic property, which is important to its practical applications.

Neuroprotective Effect of CeO2@PAA-LXW7 Against H2O2-Induced Cytotoxicity in NGF-Differentiated PC12 Cells.

PubMed

Jia, Jingjing; Zhang, Ting; Chi, Jieshan; Liu, Xiaoma; Sun, Jingjing; Xie, Qizhi; Peng, Sijia; Li, Changyan; Yi, Li

2018-06-07

CeO 2 nanoparticles (nanoceria) have been used in many studies as a powerful free radical scavenger, and LXW7, a small-molecule peptide, can specifically target the integrin αvβ3, whose neuroprotective effects have also been demonstrated. The objective of this study is to observe the neuroprotective effect and potential mechanism of CeO 2 @PAA-LXW7, a new compound that couples CeO 2 @PAA (nanoceria modified with the functional group of polyacrylic acid) with LXW7 via a series of chemical reactions, in H 2 O 2 -induced NGF-differentiated PC12 cells. We examined the effects of LXW7, CeO 2 @PAA, and CeO 2 @PAA-LXW7 on the viability of primary hippocampal neurons and found that there was no significant difference under control conditions, but increased cellular viability was observed in the case of H 2 O 2 -induced injury. We used H 2 O 2 -induced NGF-differentiated PC12 cells as the classical injury model to investigate the neuroprotective effect of CeO 2 @PAA-LXW7. In this study, LXW7, CeO 2 @PAA, and CeO 2 @PAA-LXW7 inhibit H 2 O 2 -induced oxidative stress by reducing the production of reactive oxygen species (ROS) and regulating Bax/Bcl-2, cleaved caspase-3 and mitochondrial cytochrome C (cyto C) in the apoptotic signaling pathways. We found that the levels of phosphorylation of focal adhesion kinase (FAK) and of signal transducer and activator of transcription 3 (STAT3) increased significantly in H 2 O 2 -induced NGF-differentiated PC12 cells, whereas LXW7, CeO 2 @PAA, and CeO 2 @PAA-LXW7 suppressed the increase to different degrees. Among the abovementioned changes, the inhibitory effect of CeO 2 @PAA-LXW7 on H 2 O 2 -induced changes, including the increases in the levels of p-FAK and p-STAT3, is more obvious than that of LXW7 or CeO 2 @PAA alone. In summary, these results suggest that integrin signaling participates in the regulation of apoptosis via the regulation of ROS and of the apoptosis pathway in H 2 O 2 -induced NGF-differentiated PC12 cells. LXW7, CeO

Sr(1.7)Zn(0.3)CeO4: Eu3+ novel red-emitting phosphors: synthesis and photoluminescence properties.

PubMed

Li, Haifeng; Zhao, Ran; Jia, Yonglei; Sun, Wenzhi; Fu, Jipeng; Jiang, Lihong; Zhang, Su; Pang, Ran; Li, Chengyu

2014-03-12

A series of novel red-emitting Sr1.7Zn0.3CeO4:Eu(3+) phosphors were synthesized through conventional solid-state reactions. The powder X-ray diffraction patterns and Rietveld refinement verified the similar phase of Sr1.7Zn0.3CeO4:Eu(3+) to that of Sr2CeO4. The photoluminescence spectrum exhibits that peak located at 614 nm ((5)D0-(7)F2) dominates the emission of Sr1.7Zn0.3CeO4:Eu(3+) phosphors. Because there are two regions in the excitation spectrum originating from the overlap of the Ce(4+)-O(2-) and Eu(3+)-O(2-) charge-transfer state band from 200 to 440 nm, and from the intra-4f transitions at 395 and 467 nm, the Sr1.7Zn0.3CeO4:Eu(3+) phosphors can be well excited by the near-UV light. The investigation of the concentration quenching behavior, luminescence decay curves, and lifetime implies that the dominant mechanism type leading to concentration quenching is the energy transfer among the nearest neighbor or next nearest neighbor activators. The discussion about the dependence of photoluminescence spectra on temperature shows the better thermal quenching properties of Sr1.7Zn0.3CeO4:0.3Eu(3+) than that of Sr2CeO4:Eu(3+). The experimental data indicates that Sr1.7Zn0.3CeO4:Eu(3+) phosphors have the potential as red phosphors for white light-emitting diodes.

Gaussian Decomposition of Laser Altimeter Waveforms

NASA Technical Reports Server (NTRS)

Hofton, Michelle A.; Minster, J. Bernard; Blair, J. Bryan

1999-01-01

We develop a method to decompose a laser altimeter return waveform into its Gaussian components assuming that the position of each Gaussian within the waveform can be used to calculate the mean elevation of a specific reflecting surface within the laser footprint. We estimate the number of Gaussian components from the number of inflection points of a smoothed copy of the laser waveform, and obtain initial estimates of the Gaussian half-widths and positions from the positions of its consecutive inflection points. Initial amplitude estimates are obtained using a non-negative least-squares method. To reduce the likelihood of fitting the background noise within the waveform and to minimize the number of Gaussians needed in the approximation, we rank the "importance" of each Gaussian in the decomposition using its initial half-width and amplitude estimates. The initial parameter estimates of all Gaussians ranked "important" are optimized using the Levenburg-Marquardt method. If the sum of the Gaussians does not approximate the return waveform to a prescribed accuracy, then additional Gaussians are included in the optimization procedure. The Gaussian decomposition method is demonstrated on data collected by the airborne Laser Vegetation Imaging Sensor (LVIS) in October 1997 over the Sequoia National Forest, California.

Three-photon Gaussian-Gaussian-Laguerre-Gaussian excitation of a localized atom to a highly excited Rydberg state

NASA Astrophysics Data System (ADS)

Mashhadi, L.

2017-12-01

Optical vortices are currently one of the most intensively studied topics in light-matter interaction. In this work, a three-step axial Doppler- and recoil-free Gaussian-Gaussian-Laguerre-Gaussian (GGLG) excitation of a localized atom to the highly excited Rydberg state is presented. By assuming a large detuning for intermediate states, an effective quadrupole excitation related to the Laguerre-Gaussian (LG) excitation to the highly excited Rydberg state is obtained. This special excitation system radially confines the single highly excited Rydberg atom independently of the trapping system into a sharp potential landscape into the so-called ‘far-off-resonance optical dipole-quadrupole trap’ (FORDQT). The key parameters of the Rydberg excitation to the highly excited state, namely the effective Rabi frequency and the effective detuning including a position-dependent AC Stark shift, are calculated in terms of the basic parameters of the LG beam and of the polarization of the excitation lasers. It is shown that the obtained parameters can be tuned to have a precise excitation of a single atom to the desired Rydberg state as well. The features of transferring the optical orbital and spin angular momentum of the polarized LG beam to the atom via quadrupole Rydberg excitation offer a long-lived and controllable qudit quantum memory. In addition, in contrast to the Gaussian laser beam, the doughnut-shaped LG beam makes it possible to use a high intensity laser beam to increase the signal-to-noise ratio in quadrupole excitation with minimized perturbations coming from stray light broadening in the last Rydberg excitation process.

The stability of quadratic-reciprocal functional equation

NASA Astrophysics Data System (ADS)

Song, Aimin; Song, Minwei

2018-04-01

A new quadratic-reciprocal functional equation f ((k +1 )x +k y )+f ((k +1 )x -k y )=2/f (x )f (y )[(k+1 ) 2f (y )+k2f (x )] [(k+1)2f (y )-k2f (x )] 2 is introduced. The Hyers-Ulam stability for the quadratic-reciprocal functional equations is proved in Banach spaces using the direct method and the fixed point method, respectively.

Test spaces and characterizations of quadratic spaces

NASA Astrophysics Data System (ADS)

Dvurečenskij, Anatolij

1996-10-01

We show that a test space consisting of nonzero vectors of a quadratic space E and of the set all maximal orthogonal systems in E is algebraic iff E is Dacey or, equivalently, iff E is orthomodular. In addition, we present another orthomodularity criteria of quadratic spaces, and using the result of Solèr, we show that they can imply that E is a real, complex, or quaternionic Hilbert space.

Geometric quadratic stochastic operator on countable infinite set

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganikhodjaev, Nasir; Hamzah, Nur Zatul Akmar

2015-02-03

In this paper we construct the family of Geometric quadratic stochastic operators defined on the countable sample space of nonnegative integers and investigate their trajectory behavior. Such operators can be reinterpreted in terms of of evolutionary operator of free population. We show that Geometric quadratic stochastic operators are regular transformations.

Antimicrobial potential of green synthesized CeO2 nanoparticles from Olea europaea leaf extract.

PubMed

Maqbool, Qaisar; Nazar, Mudassar; Naz, Sania; Hussain, Talib; Jabeen, Nyla; Kausar, Rizwan; Anwaar, Sadaf; Abbas, Fazal; Jan, Tariq

This article reports the green fabrication of cerium oxide nanoparticles (CeO 2 NPs) using Olea europaea leaf extract and their applications as effective antimicrobial agents. O. europaea leaf extract functions as a chelating agent for reduction of cerium nitrate. The resulting CeO 2 NPs exhibit pure single-face cubic structure, which is examined by X-ray diffraction, with a uniform spherical shape and a mean size 24 nm observed through scanning electron microscopy and transmission electron microscopy. Ultraviolet-visible spectroscopy confirms the characteristic absorption peak of CeO 2 NPs at 315 nm. Fourier transform infrared spectroscopy reflects stretching frequencies at 459 cm -1 , showing utilization of natural components for the production of NPs. Thermal gravimetric analysis predicts the successful capping of CeO 2 NPs by bioactive molecules present in the plant extract. The antimicrobial studies show significant zone of inhibition against bacterial and fungal strains. The higher activities shown by the green synthesized NPs than the plant extract lead to the conclusion that they can be effectively used in biomedical application. Furthermore, reduction of cerium salt by plant extract will reduce environmental impact over chemical synthesis.

Antimicrobial potential of green synthesized CeO2 nanoparticles from Olea europaea leaf extract

PubMed Central

Maqbool, Qaisar; Nazar, Mudassar; Naz, Sania; Hussain, Talib; Jabeen, Nyla; Kausar, Rizwan; Anwaar, Sadaf; Abbas, Fazal; Jan, Tariq

2016-01-01

This article reports the green fabrication of cerium oxide nanoparticles (CeO2 NPs) using Olea europaea leaf extract and their applications as effective antimicrobial agents. O. europaea leaf extract functions as a chelating agent for reduction of cerium nitrate. The resulting CeO2 NPs exhibit pure single-face cubic structure, which is examined by X-ray diffraction, with a uniform spherical shape and a mean size 24 nm observed through scanning electron microscopy and transmission electron microscopy. Ultraviolet-visible spectroscopy confirms the characteristic absorption peak of CeO2 NPs at 315 nm. Fourier transform infrared spectroscopy reflects stretching frequencies at 459 cm−1, showing utilization of natural components for the production of NPs. Thermal gravimetric analysis predicts the successful capping of CeO2 NPs by bioactive molecules present in the plant extract. The antimicrobial studies show significant zone of inhibition against bacterial and fungal strains. The higher activities shown by the green synthesized NPs than the plant extract lead to the conclusion that they can be effectively used in biomedical application. Furthermore, reduction of cerium salt by plant extract will reduce environmental impact over chemical synthesis. PMID:27785011

AUTONOMOUS GAUSSIAN DECOMPOSITION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lindner, Robert R.; Vera-Ciro, Carlos; Murray, Claire E.

2015-04-15

We present a new algorithm, named Autonomous Gaussian Decomposition (AGD), for automatically decomposing spectra into Gaussian components. AGD uses derivative spectroscopy and machine learning to provide optimized guesses for the number of Gaussian components in the data, and also their locations, widths, and amplitudes. We test AGD and find that it produces results comparable to human-derived solutions on 21 cm absorption spectra from the 21 cm SPectral line Observations of Neutral Gas with the EVLA (21-SPONGE) survey. We use AGD with Monte Carlo methods to derive the H i line completeness as a function of peak optical depth and velocitymore » width for the 21-SPONGE data, and also show that the results of AGD are stable against varying observational noise intensity. The autonomy and computational efficiency of the method over traditional manual Gaussian fits allow for truly unbiased comparisons between observations and simulations, and for the ability to scale up and interpret the very large data volumes from the upcoming Square Kilometer Array and pathfinder telescopes.« less

Quantification of Gaussian quantum steering.

PubMed

Kogias, Ioannis; Lee, Antony R; Ragy, Sammy; Adesso, Gerardo

2015-02-13

Einstein-Podolsky-Rosen steering incarnates a useful nonclassical correlation which sits between entanglement and Bell nonlocality. While a number of qualitative steering criteria exist, very little has been achieved for what concerns quantifying steerability. We introduce a computable measure of steering for arbitrary bipartite Gaussian states of continuous variable systems. For two-mode Gaussian states, the measure reduces to a form of coherent information, which is proven never to exceed entanglement, and to reduce to it on pure states. We provide an operational connection between our measure and the key rate in one-sided device-independent quantum key distribution. We further prove that Peres' conjecture holds in its stronger form within the fully Gaussian regime: namely, steering bound entangled Gaussian states by Gaussian measurements is impossible.

76 FR 65696 - Request for Applicants for the Appointment to the United States-Brazil CEO Forum

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-24

... Appointment to the United States- Brazil CEO Forum AGENCY: International Trade Administration, Department of Commerce. ACTION: Notice. SUMMARY: In March 2007, the Governments of the United States and Brazil established the U.S.-Brazil CEO Forum. This notice announces membership opportunities for up to three...

Quadratic Programming for Allocating Control Effort

NASA Technical Reports Server (NTRS)

Singh, Gurkirpal

2005-01-01

A computer program calculates an optimal allocation of control effort in a system that includes redundant control actuators. The program implements an iterative (but otherwise single-stage) algorithm of the quadratic-programming type. In general, in the quadratic-programming problem, one seeks the values of a set of variables that minimize a quadratic cost function, subject to a set of linear equality and inequality constraints. In this program, the cost function combines control effort (typically quantified in terms of energy or fuel consumed) and control residuals (differences between commanded and sensed values of variables to be controlled). In comparison with prior control-allocation software, this program offers approximately equal accuracy but much greater computational efficiency. In addition, this program offers flexibility, robustness to actuation failures, and a capability for selective enforcement of control requirements. The computational efficiency of this program makes it suitable for such complex, real-time applications as controlling redundant aircraft actuators or redundant spacecraft thrusters. The program is written in the C language for execution in a UNIX operating system.

Physical properties of nanostructured CeO2 thin films grown by SILAR method

NASA Astrophysics Data System (ADS)

Khan, Ishaque Ahmed; Belkhedkar, M. R.; Salodkar, R. V.; Ubale, A. U.

2018-05-01

Nanostructured CeO2 thin films have been deposited by Successive Ionic Layer Adsorption and Reaction (SILAR) method onto glass substrate using (CeNO3)3 6H2O and NaOH as cationic and anionic precursors respectively. The structural and morphological characterizations were carried out by means of X-ray diffraction, FTIR, FESEM and EDX studies. The highly resistive (1010 Ω cm) semiconducting CeO2 film exhibits 2.95 eV optical band gap.

Gaussian States Minimize the Output Entropy of One-Mode Quantum Gaussian Channels

NASA Astrophysics Data System (ADS)

De Palma, Giacomo; Trevisan, Dario; Giovannetti, Vittorio

2017-04-01

We prove the long-standing conjecture stating that Gaussian thermal input states minimize the output von Neumann entropy of one-mode phase-covariant quantum Gaussian channels among all the input states with a given entropy. Phase-covariant quantum Gaussian channels model the attenuation and the noise that affect any electromagnetic signal in the quantum regime. Our result is crucial to prove the converse theorems for both the triple trade-off region and the capacity region for broadcast communication of the Gaussian quantum-limited amplifier. Our result extends to the quantum regime the entropy power inequality that plays a key role in classical information theory. Our proof exploits a completely new technique based on the recent determination of the p →q norms of the quantum-limited amplifier [De Palma et al., arXiv:1610.09967]. This technique can be applied to any quantum channel.

Gaussian States Minimize the Output Entropy of One-Mode Quantum Gaussian Channels.

PubMed

De Palma, Giacomo; Trevisan, Dario; Giovannetti, Vittorio

2017-04-21

We prove the long-standing conjecture stating that Gaussian thermal input states minimize the output von Neumann entropy of one-mode phase-covariant quantum Gaussian channels among all the input states with a given entropy. Phase-covariant quantum Gaussian channels model the attenuation and the noise that affect any electromagnetic signal in the quantum regime. Our result is crucial to prove the converse theorems for both the triple trade-off region and the capacity region for broadcast communication of the Gaussian quantum-limited amplifier. Our result extends to the quantum regime the entropy power inequality that plays a key role in classical information theory. Our proof exploits a completely new technique based on the recent determination of the p→q norms of the quantum-limited amplifier [De Palma et al., arXiv:1610.09967]. This technique can be applied to any quantum channel.

Non-Gaussian quantum states generation and robust quantum non-Gaussianity via squeezing field

NASA Astrophysics Data System (ADS)

Tang, Xu-Bing; Gao, Fang; Wang, Yao-Xiong; Kuang, Sen; Shuang, Feng

2015-03-01

Recent studies show that quantum non-Gaussian states or using non-Gaussian operations can improve entanglement distillation, quantum swapping, teleportation, and cloning. In this work, employing a strategy of non-Gaussian operations (namely subtracting and adding a single photon), we propose a scheme to generate non-Gaussian quantum states named single-photon-added and -subtracted coherent (SPASC) superposition states by implementing Bell measurements, and then investigate the corresponding nonclassical features. By squeezed the input field, we demonstrate that robustness of non-Gaussianity can be improved. Controllable phase space distribution offers the possibility to approximately generate a displaced coherent superposition states (DCSS). The fidelity can reach up to F ≥ 0.98 and F ≥ 0.90 for size of amplitude z = 1.53 and 2.36, respectively. Project supported by the National Natural Science Foundation of China (Grant Nos. 61203061 and 61074052), the Outstanding Young Talent Foundation of Anhui Province, China (Grant No. 2012SQRL040), and the Natural Science Foundation of Anhui Province, China (Grant No. KJ2012Z035).

Some Paradoxical Results for the Quadratically Weighted Kappa

ERIC Educational Resources Information Center

Warrens, Matthijs J.

2012-01-01

The quadratically weighted kappa is the most commonly used weighted kappa statistic for summarizing interrater agreement on an ordinal scale. The paper presents several properties of the quadratically weighted kappa that are paradoxical. For agreement tables with an odd number of categories "n" it is shown that if one of the raters uses the same…

Hidden supersymmetry and quadratic deformations of the space-time conformal superalgebra

NASA Astrophysics Data System (ADS)

Yates, L. A.; Jarvis, P. D.

2018-04-01

We analyze the structure of the family of quadratic superalgebras, introduced in Jarvis et al (2011 J. Phys. A: Math. Theor. 44 235205), for the quadratic deformations of N  =  1 space-time conformal supersymmetry. We characterize in particular the ‘zero-step’ modules for this case. In such modules, the odd generators vanish identically, and the quadratic superalgebra is realized on a single irreducible representation of the even subalgebra (which is a Lie algebra). In the case under study, the quadratic deformations of N  =  1 space-time conformal supersymmetry, it is shown that each massless positive energy unitary irreducible representation (in the standard classification of Mack), forms such a zero-step module, for an appropriate parameter choice amongst the quadratic family (with vanishing central charge). For these massless particle multiplets therefore, quadratic supersymmetry is unbroken, in that the supersymmetry generators annihilate all physical states (including the vacuum state), while at the same time, superpartners do not exist.

Quadratic Frequency Modulation Signals Parameter Estimation Based on Two-Dimensional Product Modified Parameterized Chirp Rate-Quadratic Chirp Rate Distribution.

PubMed

Qu, Zhiyu; Qu, Fuxin; Hou, Changbo; Jing, Fulong

2018-05-19

In an inverse synthetic aperture radar (ISAR) imaging system for targets with complex motion, the azimuth echo signals of the target are always modeled as multicomponent quadratic frequency modulation (QFM) signals. The chirp rate (CR) and quadratic chirp rate (QCR) estimation of QFM signals is very important to solve the ISAR image defocus problem. For multicomponent QFM (multi-QFM) signals, the conventional QR and QCR estimation algorithms suffer from the cross-term and poor anti-noise ability. This paper proposes a novel estimation algorithm called a two-dimensional product modified parameterized chirp rate-quadratic chirp rate distribution (2D-PMPCRD) for QFM signals parameter estimation. The 2D-PMPCRD employs a multi-scale parametric symmetric self-correlation function and modified nonuniform fast Fourier transform-Fast Fourier transform to transform the signals into the chirp rate-quadratic chirp rate (CR-QCR) domains. It can greatly suppress the cross-terms while strengthening the auto-terms by multiplying different CR-QCR domains with different scale factors. Compared with high order ambiguity function-integrated cubic phase function and modified Lv's distribution, the simulation results verify that the 2D-PMPCRD acquires higher anti-noise performance and obtains better cross-terms suppression performance for multi-QFM signals with reasonable computation cost.

The accuracy of the Gaussian-and-finite-element-Coulomb (GFC) method for the calculation of Coulomb integrals.

PubMed

Przybytek, Michal; Helgaker, Trygve

2013-08-07

We analyze the accuracy of the Coulomb energy calculated using the Gaussian-and-finite-element-Coulomb (GFC) method. In this approach, the electrostatic potential associated with the molecular electronic density is obtained by solving the Poisson equation and then used to calculate matrix elements of the Coulomb operator. The molecular electrostatic potential is expanded in a mixed Gaussian-finite-element (GF) basis set consisting of Gaussian functions of s symmetry centered on the nuclei (with exponents obtained from a full optimization of the atomic potentials generated by the atomic densities from symmetry-averaged restricted open-shell Hartree-Fock theory) and shape functions defined on uniform finite elements. The quality of the GF basis is controlled by means of a small set of parameters; for a given width of the finite elements d, the highest accuracy is achieved at smallest computational cost when tricubic (n = 3) elements are used in combination with two (γ(H) = 2) and eight (γ(1st) = 8) Gaussians on hydrogen and first-row atoms, respectively, with exponents greater than a given threshold (αmin (G)=0.5). The error in the calculated Coulomb energy divided by the number of atoms in the system depends on the system type but is independent of the system size or the orbital basis set, vanishing approximately like d(4) with decreasing d. If the boundary conditions for the Poisson equation are calculated in an approximate way, the GFC method may lose its variational character when the finite elements are too small; with larger elements, it is less sensitive to inaccuracies in the boundary values. As it is possible to obtain accurate boundary conditions in linear time, the overall scaling of the GFC method for large systems is governed by another computational step-namely, the generation of the three-center overlap integrals with three Gaussian orbitals. The most unfavorable (nearly quadratic) scaling is observed for compact, truly three-dimensional systems

A Quadratic Spring Equation

ERIC Educational Resources Information Center

Fay, Temple H.

2010-01-01

Through numerical investigations, we study examples of the forced quadratic spring equation [image omitted]. By performing trial-and-error numerical experiments, we demonstrate the existence of stability boundaries in the phase plane indicating initial conditions yielding bounded solutions, investigate the resonance boundary in the [omega]…

On orthogonality preserving quadratic stochastic operators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukhamedov, Farrukh; Taha, Muhammad Hafizuddin Mohd

2015-05-15

A quadratic stochastic operator (in short QSO) is usually used to present the time evolution of differing species in biology. Some quadratic stochastic operators have been studied by Lotka and Volterra. In the present paper, we first give a simple characterization of Volterra QSO in terms of absolutely continuity of discrete measures. Further, we introduce a notion of orthogonal preserving QSO, and describe such kind of operators defined on two dimensional simplex. It turns out that orthogonal preserving QSOs are permutations of Volterra QSO. The associativity of genetic algebras generated by orthogonal preserving QSO is studied too.

Ionic liquid-assisted sonochemical preparation of CeO 2 nanoparticles for CO oxidation

DOE PAGES

Alammar, Tarek; Noei, Heshmat; Wang, Yuemin; ...

2014-10-10

CeO 2 nanoparticles were synthesized via a one-step ultrasound synthesis in different kinds of ionic liquids based on bis(trifluoromethanesulfonylamide, [Tf 2N] –, in combination with various cations including 1-butyl-3-methylimidazolium ([C 4mim] +), 1-ethyl-2,3-dimethylimidazolium ([Edimim] +), butyl-pyridinium([Py 4] +), 1-butyl-1-methyl-pyrrolidinium ([Pyrr 14] +), and 2-hydroxyethyl-trimethylammonium ([N 1112OH] +). Depending on synthetic parameters, such as ionic liquid, Ce(IV) precursor, heating method, and precipitator, formed ceria exhibits different morphologies, varying from nanospheres, nanorods, nanoribbons, and nanoflowers. The morphology, crystallinity, and chemical composition of the obtained materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-raymore » spectroscopy (EDX), Raman spectroscopy, and N2 adsorption. The structural and electronic properties of the as-prepared CeO 2 samples were probed by CO adsorption using IR spectroscopy under ultrahigh vacuum conditions. The catalytic activities of CeO 2 nanoparticles were investigated in the oxidation of CO. CeO 2 nanospheres obtained sonochemically in [C 4mim][Tf 2N] exhibit the best performance for low-temperature CO oxidation. As a result, the superior catalytic performance of this material can be related to its mesoporous structure, small particle size, large surface area, and high number of surface oxygen vacancy sites.« less

The properties of the anti-tumor model with coupling non-Gaussian noise and Gaussian colored noise

NASA Astrophysics Data System (ADS)

Guo, Qin; Sun, Zhongkui; Xu, Wei

2016-05-01

The anti-tumor model with correlation between multiplicative non-Gaussian noise and additive Gaussian-colored noise has been investigated in this paper. The behaviors of the stationary probability distribution demonstrate that the multiplicative non-Gaussian noise plays a dual role in the development of tumor and an appropriate additive Gaussian colored noise can lead to a minimum of the mean value of tumor cell population. The mean first passage time is calculated to quantify the effects of noises on the transition time of tumors between the stable states. An increase in both the non-Gaussian noise intensity and the departure from the Gaussian noise can accelerate the transition from the disease state to the healthy state. On the contrary, an increase in cross-correlated degree will slow down the transition. Moreover, the correlation time can enhance the stability of the disease state.

Environmentally friendly synthesis of CeO2 nanoparticles for the catalytic oxidation of benzyl alcohol to benzaldehyde and selective detection of nitrite

NASA Astrophysics Data System (ADS)

Tamizhdurai, P.; Sakthinathan, Subramanian; Chen, Shen-Ming; Shanthi, K.; Sivasanker, S.; Sangeetha, P.

2017-04-01

Cerium oxide nanoparticles (CeO2 NPs) are favorable in nanotechnology based on some remarkable properties. In this study, the crystalline CeO2 NPs are successfully prepared by an efficient microwave combustion (MCM) and conventional route sol-gel (CRSGM) methods. The structural morphology of the as-prepared CeO2 NPs was investigated by various spectroscopic and analytical techniques. Moreover, the XRD pattern confirmed the formation of CeO2 NPs as a face centered cubic structure. The magnetometer studies indicated the low saturation magnetization (23.96 emu/g) of CeO2 NPs for weak paramagnetic and high saturation magnetization (32.13 emu/g) of CeO2 NPs for super paramagnetic. After that, the oxidation effect of benzyl alcohol was investigated which reveals good conversion and selectivity. Besides, the CeO2 NPs modified glassy carbon electrode (GCE) used for the detection of nitrite with linear concentration range (0.02-1200 μM), low limit of detection (0.21 μM) and higher sensitivity (1.7238 μAμM-1 cm-2). However, the CeO2 NPs modified electrode has the fast response, high sensitivity and good selectivity. In addition, the fabricated electrode is applied for the determination of nitrite in various water samples. Eventually, the CeO2 NPs can be regarded as an effective way to enhance the catalytic activity towards the benzyl alcohol and nitrite.

Environmentally friendly synthesis of CeO2 nanoparticles for the catalytic oxidation of benzyl alcohol to benzaldehyde and selective detection of nitrite

PubMed Central

Tamizhdurai, P.; Sakthinathan, Subramanian; Chen, Shen-Ming; Shanthi, K.; Sivasanker, S.; Sangeetha, P.

2017-01-01

Cerium oxide nanoparticles (CeO2 NPs) are favorable in nanotechnology based on some remarkable properties. In this study, the crystalline CeO2 NPs are successfully prepared by an efficient microwave combustion (MCM) and conventional route sol-gel (CRSGM) methods. The structural morphology of the as-prepared CeO2 NPs was investigated by various spectroscopic and analytical techniques. Moreover, the XRD pattern confirmed the formation of CeO2 NPs as a face centered cubic structure. The magnetometer studies indicated the low saturation magnetization (23.96 emu/g) of CeO2 NPs for weak paramagnetic and high saturation magnetization (32.13 emu/g) of CeO2 NPs for super paramagnetic. After that, the oxidation effect of benzyl alcohol was investigated which reveals good conversion and selectivity. Besides, the CeO2 NPs modified glassy carbon electrode (GCE) used for the detection of nitrite with linear concentration range (0.02–1200 μM), low limit of detection (0.21 μM) and higher sensitivity (1.7238 μAμM−1 cm−2). However, the CeO2 NPs modified electrode has the fast response, high sensitivity and good selectivity. In addition, the fabricated electrode is applied for the determination of nitrite in various water samples. Eventually, the CeO2 NPs can be regarded as an effective way to enhance the catalytic activity towards the benzyl alcohol and nitrite. PMID:28406231

Synthesis and Characterization of CeO2 Nanoparticles via Solution Combustion Method for Photocatalytic and Antibacterial Activity Studies

PubMed Central

Ravishankar, Thammadihalli Nanjundaiah; Ramakrishnappa, Thippeswamy; Nagaraju, Ganganagappa; Rajanaika, Hanumanaika

2015-01-01

CeO2 nanoparticles have been proven to be competent photocatalysts for environmental applications because of their strong redox ability, nontoxicity, long-term stability, and low cost. We have synthesized CeO2 nanoparticles via solution combustion method using ceric ammonium nitrate as an oxidizer and ethylenediaminetetraacetic acid (EDTA) as fuel at 450 °C. These nanoparticles exhibit good photocatalytic degradation and antibacterial activity. The obtained product was characterized by various techniques. X-ray diffraction data confirms a cerianite structure: a cubic phase CeO2 having crystallite size of 35 nm. The infrared spectrum shows a strong band below 700 cm−1 due to the Ce−O−Ce stretching vibrations. The UV/Vis spectrum shows maximum absorption at 302 nm. The photoluminescence spectrum shows characteristic peaks of CeO2 nanoparticles. Scanning electron microscopy (SEM) images clearly show the presence of a porous network with a lot of voids. From transmission electron microscopy (TEM) images, it is clear that the particles are almost spherical, and the average size of the nanoparticles is found to be 42 nm. CeO2 nanoparticles exhibit photocatalytic activity against trypan blue at pH 10 in UV light, and the reaction follows pseudo first-order kinetics. Finally, CeO2 nanoparticles also reduce CrVI to CrIII and show antibacterial activity against Pseudomonas aeruginosa. PMID:25969812

Laguerre-Gaussian, Hermite-Gaussian, Bessel-Gaussian, and Finite-Energy Airy Beams Carrying Orbital Angular Momentum in Strongly Nonlocal Nonlinear Media

NASA Astrophysics Data System (ADS)

Wu, Zhenkun; Gu, Yuzong

2016-12-01

The propagation of two-dimensional beams is analytically and numerically investigated in strongly nonlocal nonlinear media (SNNM) based on the ABCD matrix. The two-dimensional beams reported in this paper are described by the product of the superposition of generalized Laguerre-Gaussian (LG), Hermite-Gaussian (HG), Bessel-Gaussian (BG), and circular Airy (CA) beams, carrying an orbital angular momentum (OAM). Owing to OAM and the modulation of SNNM, we find that the propagation of these two-dimensional beams exhibits complete rotation and periodic inversion: the spatial intensity profile first extends and then diminishes, and during the propagation the process repeats to form a breath-like phenomenon.

The Lived Experiences of Asian Americans Who Became Chief Executive Officers (CEOs) of California Community Colleges

ERIC Educational Resources Information Center

Ramones, Eric

2017-01-01

The purpose of this phenomenological study was to explore the lived experiences of Asian Americans who became chief executive officers (CEOs) of a California Community College District. This study discussed the experiences, the influence of Asian culture, the perception of Asian Americans, and the challenges encountered by Asian American CEOs. To…

Effect of Co doping on structural and mechanical properties of CeO2

NASA Astrophysics Data System (ADS)

Tiwari, Saurabh; Balasubramanian, Nivedha; Biring, Sajal; Sen, Somaditya

2018-05-01

Sol-gel synthesized nanocrystalline Co doped CeO2 powders [(Ce1-xCoxO2; x=0, 0.03)] were made into cylindrical discs by uniaxial pressing and sintered at 1500°C for 24h to measure mechanical properties. The pure phase formation of undoped and Co doped samples were confirmed by X-ray diffraction and Raman analysis. The scanning electron microscopy (SEM) was used for observing the microstructure of sintered samples to investigate density, porosity, and grain size. The grains size observed for 1500°C sintered samples 5-8 µm. Vickers indentation method used for investigating the micro-hardness. For undoped CeO2 micro-hardness was found 6.2 GPa which decreased with Co doping. It was found that samples follow indentation size effect (ISE) and follow elastic than plastic deformation. Enhanced ductile nature with Co doping in CeO2 made it more promising material for optoelectronic device applications.

High-Order Local Pooling and Encoding Gaussians Over a Dictionary of Gaussians.

PubMed

Li, Peihua; Zeng, Hui; Wang, Qilong; Shiu, Simon C K; Zhang, Lei

2017-07-01

Local pooling (LP) in configuration (feature) space proposed by Boureau et al. explicitly restricts similar features to be aggregated, which can preserve as much discriminative information as possible. At the time it appeared, this method combined with sparse coding achieved competitive classification results with only a small dictionary. However, its performance lags far behind the state-of-the-art results as only the zero-order information is exploited. Inspired by the success of high-order statistical information in existing advanced feature coding or pooling methods, we make an attempt to address the limitation of LP. To this end, we present a novel method called high-order LP (HO-LP) to leverage the information higher than the zero-order one. Our idea is intuitively simple: we compute the first- and second-order statistics per configuration bin and model them as a Gaussian. Accordingly, we employ a collection of Gaussians as visual words to represent the universal probability distribution of features from all classes. Our problem is naturally formulated as encoding Gaussians over a dictionary of Gaussians as visual words. This problem, however, is challenging since the space of Gaussians is not a Euclidean space but forms a Riemannian manifold. We address this challenge by mapping Gaussians into the Euclidean space, which enables us to perform coding with common Euclidean operations rather than complex and often expensive Riemannian operations. Our HO-LP preserves the advantages of the original LP: pooling only similar features and using a small dictionary. Meanwhile, it achieves very promising performance on standard benchmarks, with either conventional, hand-engineered features or deep learning-based features.

Improving the Efficiency of DASC by Adding CeO2/CuO Hybrid Nanoparticles in Water

NASA Astrophysics Data System (ADS)

Midhun Mohan, V.; Sajeeb, A. M.

Solar energy is the abundantly available source of renewable energy with least impact on environment. Direct absorption solar collector (DASC) is the commonly used device to absorb heat directly from sun and make use of it for different heating applications. In the past, many experiments have been done to increase the efficiency of DASC using nanofluids. In this paper, an examination of solar collector efficiency for hybrid CeO2/CuO-water (0.1% by volume) nanofluid under various flow rates and proportions of CeO2/CuO nanoparticles is investigated. The experiments were conducted at flow rates spanning from 20cc/min to 100cc/min and with CeO2/CuO nanoparticles proportions of 1:0, 1:0.5, 1:1, 0.5:1 and 0:1. The efficiency increases from 16.5% to 51.6% when the flow rate is increased from 20cc/min to 100cc/min for hybrid CeO2/CuO (1:1)-water nanofluid. The results also showed an increase in efficiency of 13.8%, 18.1%, 24.3%, 24.9% and 26.1% with hybrid combination of CeO2/CuO at ratios 1:0, 1:0.5, 1:1, 0.5:1 and 0:1, respectively, in comparison with water at a flow rate of 100cc/min.

Optimal reduced-rank quadratic classifiers using the Fukunaga-Koontz transform with applications to automated target recognition

NASA Astrophysics Data System (ADS)

Huo, Xiaoming; Elad, Michael; Flesia, Ana G.; Muise, Robert R.; Stanfill, S. Robert; Friedman, Jerome; Popescu, Bogdan; Chen, Jihong; Mahalanobis, Abhijit; Donoho, David L.

2003-09-01

In target recognition applications of discriminant of classification analysis, each 'feature' is a result of a convolution of an imagery with a filter, which may be derived from a feature vector. It is important to use relatively few features. We analyze an optimal reduced-rank classifier under the two-class situation. Assuming each population is Gaussian and has zero mean, and the classes differ through the covariance matrices: ∑1 and ∑2. The following matrix is considered: Λ=(∑1+∑2)-1/2∑1(∑1+∑2)-1/2. We show that the k eigenvectors of this matrix whose eigenvalues are most different from 1/2 offer the best rank k approximation to the maximum likelihood classifier. The matrix Λ and its eigenvectors have been introduced by Fukunaga and Koontz; hence this analysis gives a new interpretation of the well known Fukunaga-Koontz transform. The optimality that is promised in this method hold if the two populations are exactly Guassian with the same means. To check the applicability of this approach to real data, an experiment is performed, in which several 'modern' classifiers were used on an Infrared ATR data. In these experiments, a reduced-rank classifier-Tuned Basis Functions-outperforms others. The competitive performance of the optimal reduced-rank quadratic classifier suggests that, at least for classification purposes, the imagery data behaves in a nearly-Gaussian fashion.

The Mystical "Quadratic Formula."

ERIC Educational Resources Information Center

March, Robert H.

1993-01-01

Uses projectile motion to explain the two roots found when using the quadratic formula. An example is provided for finding the time of flight for a projectile which has a negative root implying a negative time of flight. This negative time of flight also has a useful physical meaning. (MVL)

Radiation pressure acceleration of corrugated thin foils by Gaussian and super-Gaussian beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adusumilli, K.; Goyal, D.; Tripathi, V. K.

Rayleigh-Taylor instability of radiation pressure accelerated ultrathin foils by laser having Gaussian and super-Gaussian intensity distribution is investigated using a single fluid code. The foil is allowed to have ring shaped surface ripples. The radiation pressure force on such a foil is non-uniform with finite transverse component F{sub r}; F{sub r} varies periodically with r. Subsequently, the ripple grows as the foil moves ahead along z. With a Gaussian beam, the foil acquires an overall curvature due to non-uniformity in radiation pressure and gets thinner. In the process, the ripple perturbation is considerably washed off. With super-Gaussian beam, the ripplemore » is found to be more strongly washed out. In order to avoid transmission of the laser through the thinning foil, a criterion on the foil thickness is obtained.« less

Linear quadratic optimization for positive LTI system

NASA Astrophysics Data System (ADS)

Muhafzan, Yenti, Syafrida Wirma; Zulakmal

2017-05-01

Nowaday the linear quadratic optimization subject to positive linear time invariant (LTI) system constitute an interesting study considering it can become a mathematical model of variety of real problem whose variables have to nonnegative and trajectories generated by these variables must be nonnegative. In this paper we propose a method to generate an optimal control of linear quadratic optimization subject to positive linear time invariant (LTI) system. A sufficient condition that guarantee the existence of such optimal control is discussed.

Interfacial interactions of semiconductor with graphene and reduced graphene oxide: CeO2 as a case study.

PubMed

Xu, Liang; Huang, Wei-Qing; Wang, Ling-Ling; Huang, Gui-Fang

2014-11-26

The pursuit of superb building blocks of light harvesting systems has stimulated increasing efforts to develop graphene (GR)-based semiconductor composites for solar cells and photocatalysts. One critical issue for GR-based composites is understanding the interaction between their components, a problem that remains unresolved after intense experimental investigation. Here, we use cerium dioxide (CeO2) as a model semiconductor to systematically explore the interaction of semiconductor with GR and reduced graphene oxide (RGO) with large-scale ab initio calculations. The amount of charge transferred at the interfaces increases with the concentration of O atoms, demonstrating that the interaction between CeO2 and RGO is much stronger than that between CeO2 and GR due to the decrease of the average equilibrium distance between the interfaces. The stronger interaction between semiconductor and RGO is expected to be general, as evidenced by the results of two paradigms of TiO2 and Ag3PO4 coupled with RGO. The interfacial interaction can tune the band structure: the CeO2(111)/GR interface is a type-I heterojunction, while a type-II staggered band alignment exists between the CeO2(111) surface and RGO. The smaller band gap, type-II heterojunction, and negatively charged O atoms on the RGO as active sites are responsible for the enhanced photoactivity of CeO2/RGO composite. These findings can rationalize the available experimental reports and enrich our understanding of the interaction of GR-based composites for developing high-performance photocatalysts and solar cells.

Determining the Optimal Solution for Quadratically Constrained Quadratic Programming (QCQP) on Energy-Saving Generation Dispatch Problem

NASA Astrophysics Data System (ADS)

Lesmana, E.; Chaerani, D.; Khansa, H. N.

2018-03-01

Energy-Saving Generation Dispatch (ESGD) is a scheme made by Chinese Government in attempt to minimize CO2 emission produced by power plant. This scheme is made related to global warming which is primarily caused by too much CO2 in earth’s atmosphere, and while the need of electricity is something absolute, the power plants producing it are mostly thermal-power plant which produced many CO2. Many approach to fulfill this scheme has been made, one of them came through Minimum Cost Flow in which resulted in a Quadratically Constrained Quadratic Programming (QCQP) form. In this paper, ESGD problem with Minimum Cost Flow in QCQP form will be solved using Lagrange’s Multiplier Method

Extremality of Gaussian quantum states.

PubMed

Wolf, Michael M; Giedke, Geza; Cirac, J Ignacio

2006-03-03

We investigate Gaussian quantum states in view of their exceptional role within the space of all continuous variables states. A general method for deriving extremality results is provided and applied to entanglement measures, secret key distillation and the classical capacity of bosonic quantum channels. We prove that for every given covariance matrix the distillable secret key rate and the entanglement, if measured appropriately, are minimized by Gaussian states. This result leads to a clearer picture of the validity of frequently made Gaussian approximations. Moreover, it implies that Gaussian encodings are optimal for the transmission of classical information through bosonic channels, if the capacity is additive.

Effect of Zn doping on structural, optical and thermal properties of CeO2 nanoparticles

NASA Astrophysics Data System (ADS)

Ramasamy, V.; Vijayalakshmi, G.

2015-09-01

The undoped and Zn doped CeO2 nanoparticles were synthesized by chemical precipitation method at room temperature. The undoped and Zn doped CeO2 nanoparticles have been characterized by X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), ultraviolet visible and photoluminescence (PL) spectroscopy, Fourier transform infrared spectroscopy (FTIR) and thermogravimetry and differential thermal analysis (TG-DTA). The cubic fluorite structures of the CeO2 nanoparticles were determined by XRD. The influence of particle size on structural parameters such as lattice parameter (a), inter planar distance (d), dislocation density (δ), microstrain (ε), lattice strain (η) and texture co-efficient (TC) were also determined. The lattice strains were determined by Williamson-Hall plot method. The effect of Zn doping with shifting of the bands were observed by UV-Vis spectroscopy and also their optical band gap were determined. The emission spectra and energy band diagram of the undoped and Zn doped samples were derived from PL spectroscopy. The structural bond vibrations of undoped and Zn doped CeO2 nanoparticles were analyzed by FTIR spectroscopy. The thermal property (weight loss and decomposition) of the sample is observed by TG-DTA curve.

PSQP: Puzzle Solving by Quadratic Programming.

PubMed

Andalo, Fernanda A; Taubin, Gabriel; Goldenstein, Siome

2017-02-01

In this article we present the first effective method based on global optimization for the reconstruction of image puzzles comprising rectangle pieces-Puzzle Solving by Quadratic Programming (PSQP). The proposed novel mathematical formulation reduces the problem to the maximization of a constrained quadratic function, which is solved via a gradient ascent approach. The proposed method is deterministic and can deal with arbitrary identical rectangular pieces. We provide experimental results showing its effectiveness when compared to state-of-the-art approaches. Although the method was developed to solve image puzzles, we also show how to apply it to the reconstruction of simulated strip-shredded documents, broadening its applicability.

Visualising the Roots of Quadratic Equations with Complex Coefficients

ERIC Educational Resources Information Center

Bardell, Nicholas S.

2014-01-01

This paper is a natural extension of the root visualisation techniques first presented by Bardell (2012) for quadratic equations with real coefficients. Consideration is now given to the familiar quadratic equation "y = ax[superscript 2] + bx + c" in which the coefficients "a," "b," "c" are generally…

Non-Gaussianity and cross-scale coupling in interplanetary magnetic field turbulence during a rope-rope magnetic reconnection event

NASA Astrophysics Data System (ADS)

Miranda, Rodrigo A.; Schelin, Adriane B.; Chian, Abraham C.-L.; Ferreira, José L.

2018-03-01

In a recent paper (Chian et al., 2016) it was shown that magnetic reconnection at the interface region between two magnetic flux ropes is responsible for the genesis of interplanetary intermittent turbulence. The normalized third-order moment (skewness) and the normalized fourth-order moment (kurtosis) display a quadratic relation with a parabolic shape that is commonly observed in observational data from turbulence in fluids and plasmas, and is linked to non-Gaussian fluctuations due to coherent structures. In this paper we perform a detailed study of the relation between the skewness and the kurtosis of the modulus of the magnetic field |B| during a triple interplanetary magnetic flux rope event. In addition, we investigate the skewness-kurtosis relation of two-point differences of |B| for the same event. The parabolic relation displays scale dependence and is found to be enhanced during magnetic reconnection, rendering support for the generation of non-Gaussian coherent structures via rope-rope magnetic reconnection. Our results also indicate that a direct coupling between the scales of magnetic flux ropes and the scales within the inertial subrange occurs in the solar wind.

Breaking Gaussian incompatibility on continuous variable quantum systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heinosaari, Teiko, E-mail: teiko.heinosaari@utu.fi; Kiukas, Jukka, E-mail: jukka.kiukas@aber.ac.uk; Schultz, Jussi, E-mail: jussi.schultz@gmail.com

2015-08-15

We characterise Gaussian quantum channels that are Gaussian incompatibility breaking, that is, transform every set of Gaussian measurements into a set obtainable from a joint Gaussian observable via Gaussian postprocessing. Such channels represent local noise which renders measurements useless for Gaussian EPR-steering, providing the appropriate generalisation of entanglement breaking channels for this scenario. Understanding the structure of Gaussian incompatibility breaking channels contributes to the resource theory of noisy continuous variable quantum information protocols.

A facile synthesis for cauliflower like CeO2 catalysts from Ce-BTC precursor and their catalytic performance for CO oxidation

NASA Astrophysics Data System (ADS)

Zhang, Xiaodong; Hou, Fulin; Yang, Yang; Wang, Yuxin; Liu, Ning; Chen, Dan; Yang, Yiqiong

2017-11-01

The paper presents a novel and facile method for preparing cauliflowerlike CeO2 through direct decomposition of cerium based metal-organic framework (MOF) Ce-BTC (BTC = 1,3,5-benzenetricarboxylic acid) straw in air. Several analytical tools such as Scanning electron microscopy (SEM), X-ray diffraction (XRD), Thermogravimetric (TG), N2 adsorption-desorption, Temperature programmed reduction (TPR), Raman, X-ray photoelectron spectroscopic (XPS) and Photoluminescence (PL) have been used to characterize Ce-BTC and CeO2. The Ce-BTC calcined at 500 °C (CeO2-500) maintains the morphology of its template ;Ce-BTC; and forms a special cauliflower-like structure. XRD patterns showed that the catalyst has a perfect CeO2 crystal structure and has a smaller particle size. The prepared CeO2 cauliflowers exhibit excellent catalytic activities, long-term stability, and cycling stability for CO oxidation. The improved catalytic activities could be attributed to porous nanorods of CeO2 cauliflowers, which provide more active sites and oxygen vacancy for CO oxidation.

Plasma-assisted adsorption of elemental mercury on CeO2/TiO2 at low temperatures

NASA Astrophysics Data System (ADS)

Liu, Lu; Zheng, Chenghang; Gao, Xiang

2017-11-01

Mercury is a kind of pollutants contained in flue gas which is hazardous for human beings. In this work, CeO2 was packed in the discharge zone of a plasma reactor to adsorb elemental mercury at low temperatures. Plasma-catalyst reactor can remove Hg0 efficiently with CeO2/TiO2 catalysts packed in the discharge zone. The Hg0 concentration continued to decrease gradually when the plasma was turned on, but not sank rapidly. This tendency was different with other catalysts. The treatment of plasma to CeO2/TiO2 catalysts has a promotion effect on the adsorption of Hg0. Plasma has the effect of changing the surface properties of the catalysts and the changes would restitute if the condition changed. The long-running test demonstrated that this method is an effective way to remove Hg0. The removal efficiency remained at above 99% throughout 12 hours when plasma had been turned on (15kV, 0.5 g packed CeO2/TiO2).

Evaluation of Pd Nanoparticle-Decorated CeO2-MWCNT Nanocomposite as an Electrocatalyst for Formic Acid Fuel Cells

NASA Astrophysics Data System (ADS)

Saleem, Junaid; Safdar Hossain, SK.; Al-Ahmed, Amir; Rahman, Ateequr; McKay, Gordon; Hossain, Mohammed M.

2018-04-01

In this work, CeO2-modified Pd/CeO2-carbon nanotube (CNT) electrocatalyst for the electro-oxidation of formic acid has been investigated. The support CNT was first modified with different amounts (5-30 wt.%) of CeO2 using a precipitation-deposition method. The electrocatalysts were developed by dispersing Pd on the CeO2-CNT supports using the borohydride reduction method. The synthesized electrocatalysts were analyzed for composition, morphology and electronic structure using x-ray diffraction (XRD), scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM/EDX), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA) techniques. The formation of Pd nanoparticles on the CeO2-CNT support was confirmed using TEM. The activity of Pd/CeO2-CNT and of Pd-CNT samples upon oxidation of formic acid was evaluated by using carbon monoxide stripping voltammetry, cyclic voltammetry, and chronoamperometry. The addition of moderate amounts of cerium oxide (up to 10 wt.%) significantly improved the activity of Pd/CeO2-CNT compared to the unmodified Pd-CNT. Pd/10 wt.% CeO2-CNT showed a current density of 2 A mg-1, which is ten times higher than that of the unmodified Pd-CNT (0.2 A mg-1). Similarly, the power density obtained for Pd/10 wt.% CeO2-CNT in an air-breathing formic acid fuel cell was 6.8 mW/cm2 which is two times higher than Pd-CNT (3.2 mW/cm2), thus exhibiting the promotional effects of CeO2 to Pd/CeO2-CNT. A plausible justification for the improved catalytic performance and stability is provided in the light of the physical characterization results.

A comparative investigation of SO2 oxidative transfer over CuO with a CeO2 surface

NASA Astrophysics Data System (ADS)

Liu, Yifeng; Shen, Benxian; Pi, Zhipeng; Chen, Hua; Zhao, Jigang

2017-04-01

To further improve the catalytic desulfurization function of the Mg-Al spinel sulfur transfer agent in a fluid catalytic cracking (FCC) unit, the reaction paths of SO2 oxidation by O2 over the metal oxide surface of CuO (111) and CeO2 (111) were investigated. In reference to the fact that SO2 reacting with O2 over CuO was a Mars-van Krevelen cycle, a similar reaction law for SO2 oxidation over CeO2 was also verified by characterization methods (e.g., IR, XPS). Meanwhile, the molecular simulation results indicated that the rate-control step of SO2 oxidation over CeO2 (111) and CuO (111) was a SO3 desorption step. The lower energy barrier in the rate-control step corresponded to better catalytic performance; hence, it could explain the reason that CeO2 had a better sulfur oxidization transfer performance than CuO.

Biennial CEO Tenure and Retention Study. 2002 Update.

ERIC Educational Resources Information Center

Community Coll. League of California, Sacramento.

This is the third review of data on the retention and tenure of California Community College (CCC) district CEOs (which includes chancellors and superintendent/presidents). The review indicates that (1) length of service levels are continuing to remain slightly higher (5.5 years) since their lows of 4.4 years in the initial study in 1995 and 1996;…

Effect of CeO2 on TiC Morphology in Ni-Based Composite Coating

NASA Astrophysics Data System (ADS)

Cai, Yangchuan; Luo, Zhen; Chen, Yao

2018-03-01

The TiC/Ni composite coating with different content of CeO2 was fabricated on the Cr12MoV steel by laser cladding. The microstructure of cladding layers with the different content of CeO2 from the bottom to the surface is columnar crystal, cellular crystal, and equiaxed crystal. When the content of CeO2 is 0 %, the cladding layer has a coarse and nonuniform microstructure and TiC particles gathering in the cladding layer, and then the wear resistance was reduced. Appropriate rare-earth elements refined and homogenised the microstructure and enhanced the content of carbides, precipitated TiC particles and original TiC particles were spheroidised and refined, the wear resistance of the cladding layer was improved significantly. Excessive rare-earth elements polluted the grain boundaries and made the excessive burning loss of TiC particles that reduced the wear resistance of the cladding layer.

Arbitrage with fractional Gaussian processes

NASA Astrophysics Data System (ADS)

Zhang, Xili; Xiao, Weilin

2017-04-01

While the arbitrage opportunity in the Black-Scholes model driven by fractional Brownian motion has a long history, the arbitrage strategy in the Black-Scholes model driven by general fractional Gaussian processes is in its infancy. The development of stochastic calculus with respect to fractional Gaussian processes allowed us to study such models. In this paper, following the idea of Shiryaev (1998), an arbitrage strategy is constructed for the Black-Scholes model driven by fractional Gaussian processes, when the stochastic integral is interpreted in the Riemann-Stieltjes sense. Arbitrage opportunities in some fractional Gaussian processes, including fractional Brownian motion, sub-fractional Brownian motion, bi-fractional Brownian motion, weighted-fractional Brownian motion and tempered fractional Brownian motion, are also investigated.

The effect of fission-energy Xe ion irradiation on the structural integrity and dissolution of the CeO2 matrix

NASA Astrophysics Data System (ADS)

Popel, A. J.; Le Solliec, S.; Lampronti, G. I.; Day, J.; Petrov, P. K.; Farnan, I.

2017-02-01

This work considers the effect of fission fragment damage on the structural integrity and dissolution of the CeO2 matrix in water, as a simulant for the UO2 matrix of spent nuclear fuel. For this purpose, thin films of CeO2 on Si substrates were produced and irradiated by 92 MeV 129Xe23+ ions to a fluence of 4.8 × 1015 ions/cm2 to simulate fission damage that occurs within nuclear fuels along with bulk CeO2 samples. The irradiated and unirradiated samples were characterised and a static batch dissolution experiment was conducted to study the effect of the induced irradiation damage on dissolution of the CeO2 matrix. Complex restructuring took place in the irradiated films and the irradiated samples showed an increase in the amount of dissolved cerium, as compared to the corresponding unirradiated samples. Secondary phases were also observed on the surface of the irradiated CeO2 films after the dissolution experiment.

Numerical modeling of macrodispersion in heterogeneous media: a comparison of multi-Gaussian and non-multi-Gaussian models

NASA Astrophysics Data System (ADS)

Wen, Xian-Huan; Gómez-Hernández, J. Jaime

1998-03-01

The macrodispersion of an inert solute in a 2-D heterogeneous porous media is estimated numerically in a series of fields of varying heterogeneity. Four different random function (RF) models are used to model log-transmissivity (ln T) spatial variability, and for each of these models, ln T variance is varied from 0.1 to 2.0. The four RF models share the same univariate Gaussian histogram and the same isotropic covariance, but differ from one another in terms of the spatial connectivity patterns at extreme transmissivity values. More specifically, model A is a multivariate Gaussian model for which, by definition, extreme values (both high and low) are spatially uncorrelated. The other three models are non-multi-Gaussian: model B with high connectivity of high extreme values, model C with high connectivity of low extreme values, and model D with high connectivities of both high and low extreme values. Residence time distributions (RTDs) and macrodispersivities (longitudinal and transverse) are computed on ln T fields corresponding to the different RF models, for two different flow directions and at several scales. They are compared with each other, as well as with predicted values based on first-order analytical results. Numerically derived RTDs and macrodispersivities for the multi-Gaussian model are in good agreement with analytically derived values using first-order theories for log-transmissivity variance up to 2.0. The results from the non-multi-Gaussian models differ from each other and deviate largely from the multi-Gaussian results even when ln T variance is small. RTDs in non-multi-Gaussian realizations with high connectivity at high extreme values display earlier breakthrough than in multi-Gaussian realizations, whereas later breakthrough and longer tails are observed for RTDs from non-multi-Gaussian realizations with high connectivity at low extreme values. Longitudinal macrodispersivities in the non-multi-Gaussian realizations are, in general, larger than

Geometric Approaches to Quadratic Equations from Other Times and Places.

ERIC Educational Resources Information Center

Allaire, Patricia R.; Bradley, Robert E.

2001-01-01

Focuses on geometric solutions of quadratic problems. Presents a collection of geometric techniques from ancient Babylonia, classical Greece, medieval Arabia, and early modern Europe to enhance the quadratic equation portion of an algebra course. (KHR)

CeO2 nanoparticles induce no changes in phenanthrene toxicity to the soil organisms Porcellionides pruinosus and Folsomia candida.

PubMed

Tourinho, Paula S; Waalewijn-Kool, Pauline L; Zantkuijl, Irene; Jurkschat, Kerstin; Svendsen, Claus; Soares, Amadeu M V M; Loureiro, Susana; van Gestel, Cornelis A M

2015-03-01

Cerium oxide nanoparticles (CeO2 NPs) are used as diesel fuel additives to catalyze oxidation. Phenanthrene is a major component of diesel exhaust particles and one of the most common pollutants in the environment. This study aimed at determining the effect of CeO2 NPs on the toxicity of phenanthrene in Lufa 2.2 standard soil for the isopod Porcellionides pruinosus and the springtail Folsomia candida. Toxicity tests were performed in the presence of CeO2 concentrations of 10, 100 or 1000mg Ce/kg dry soil and compared with results in the absence of CeO2 NPs. CeO2 NPs had no adverse effects on isopod survival and growth or springtail survival and reproduction. For the isopods, LC50s for the effect of phenanthrene ranged from 110 to 143mg/kg dry soil, and EC50s from 17.6 to 31.6mg/kg dry soil. For the springtails, LC50s ranged between 61.5 and 88.3mg/kg dry soil and EC50s from 52.2 to 76.7mg/kg dry soil. From this study it may be concluded that CeO2 NPs have a low toxicity and do not affect toxicity of phenanthrene to isopods and springtails. Copyright © 2014 Elsevier Inc. All rights reserved.

Facile synthesis of ferromagnetic Ni doped CeO2 nanoparticles with enhanced anticancer activity

NASA Astrophysics Data System (ADS)

Abbas, Fazal; Jan, Tariq; Iqbal, Javed; Ahmad, Ishaq; Naqvi, M. Sajjad H.; Malik, Maaza

2015-12-01

NixCe1-xO2 (where x = 0, 0.01, 0.03, 0.05 and 0.07) nanoparticles were synthesized by soft chemical method and were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, UV-vis absorption spectroscopy and vibrating sample magnetometer (VSM). XRD and Raman results indicated the formation of single phase cubic fluorite structure for the synthesized nanoparticles. Ni dopant induced excessive structural changes such as decrease in crystallite size as well as lattice constants and enhancement in oxygen vacancies in CeO2 crystal structure. These structural variations significantly influenced the optical and magnetic properties of CeO2 nanoparticles. The synthesized NixCe1-xO2 nanoparticles exhibited room temperature ferromagnetic behavior. Ni doping induced effects on the cytotoxicity of CeO2 nanoparticles were examined against HEK-293 healthy cell line and SH-SY5Y neuroblastoma cancer cell line. The prepared NixCe1-xO2 nanoparticles demonstrated differential cytotoxicity. Furthermore, anticancer activity of CeO2 nanoparticles observed to be significantly enhanced with Ni doping which was found to be strongly correlated with the level of reactive oxygen species (ROS) production. The prepared ferromagnetic NixCe1-xO2 nanoparticles with differential cytotoxic nature may be potential for future targeted cancer therapy.

Linear state feedback, quadratic weights, and closed loop eigenstructures. M.S. Thesis

NASA Technical Reports Server (NTRS)

Thompson, P. M.

1979-01-01

Results are given on the relationships between closed loop eigenstructures, state feedback gain matrices of the linear state feedback problem, and quadratic weights of the linear quadratic regulator. Equations are derived for the angles of general multivariable root loci and linear quadratic optimal root loci, including angles of departure and approach. The generalized eigenvalue problem is used for the first time to compute angles of approach. Equations are also derived to find the sensitivity of closed loop eigenvalues and the directional derivatives of closed loop eigenvectors (with respect to a scalar multiplying the feedback gain matrix or the quadratic control weight). An equivalence class of quadratic weights that produce the same asymptotic eigenstructure is defined, sufficient conditions to be in it are given, a canonical element is defined, and an algorithm to find it is given. The behavior of the optimal root locus in the nonasymptotic region is shown to be different for quadratic weights with the same asymptotic properties.

Self-accelerating Airy-Ince-Gaussian and Airy-Helical-Ince-Gaussian light bullets in free space.

PubMed

Peng, Yulian; Chen, Bo; Peng, Xi; Zhou, Meiling; Zhang, Liping; Li, Dongdong; Deng, Dongmei

2016-08-22

The evolution of the three-dimensional (3D) self-accelerating Airy-Ince-Gaussian (AiIG) and Airy-Helical-Ince-Gaussian (AiHIG) light bullets is investigated by solving the (3+1)D linear spatiotemporal evolution equation of an optical field analytically. As far as we know, the numerical experimental demonstrations of the Ince-Gaussian (IG) and Helical-Ince-Gaussian (HIG) beams in various modes are first developed to study the evolution characteristics of the different 3D spatiotemporal light bullets. A conclusion can be drawn that the different photoelastics, pulse stacked, boundary, elliptical ring and physically separated in-line vortices can be achieved by adjusting the ellipticity, the evolution distance and the mode-number of light bullets.

Analysis of Students' Error in Learning of Quadratic Equations

ERIC Educational Resources Information Center

Zakaria, Effandi; Ibrahim; Maat, Siti Mistima

2010-01-01

The purpose of the study was to determine the students' error in learning quadratic equation. The samples were 30 form three students from a secondary school in Jambi, Indonesia. Diagnostic test was used as the instrument of this study that included three components: factorization, completing the square and quadratic formula. Diagnostic interview…

Investigation of the physical, optical, and photocatalytic properties of CeO2/Fe-doped InVO4 composite

NASA Astrophysics Data System (ADS)

Chaison, Jindaporn; Wetchakun, Khatcharin; Wetchakun, Natda

2017-12-01

The CeO2/Fe-doped InVO4 composites with various Fe concentrations (0.5, 1.0, 2.0, 5.0 and 6.0 mol%) was synthesized by homogeneous precipitation and hydrothermal methods. The as-synthesized samples were characterized by powder X-ray diffraction (XRD), Brunauer Emmett and Teller (BET)-specific surface area, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and UV-visible diffuse reflectance spectroscopy (DRS). Fe-doping into InVO4 crystal induces the distortion of the crystalline structure, the transformation of InVO4 morphology, and the new energy subband level generation of Fe between the CB and VB edge of InVO4. The electron excitation from the VB to Fe orbitals results in the decreased band gap and the extended absorption of visible-light, and thus enhances its photocatalytic performance. Visible-light-driven photocatalytic degradation of Rhodamine B (RhB) dye in water was used to evaluate the photocatalytic performance of CeO2/Fe-doped InVO4 composites. The results revealed that there is an optimum Fe (5.0 mol %) doping level. The composite with the optimum doping level obtains high photocatalytic activity of CeO2/Fe-doped InVO4 composite compared to pure CeO2 and pure InVO4 host. The increase of photocatalytic activity of CeO2/Fe-doped InVO4 composite was ascribed to the surface area, crystal defect, and band gap energy. Moreover, the photocatalytic enhancement is also because iron ions act as a trapping site, which results in the higher separation efficiency of photogenerated electrons and holes pairs in the CeO2/InVO4 composite. The evaluation of radical scavengers confirmed that hydroxyl radical was the main active species during the photodegradation of RhB. These synergistic effects are responsible for the enhanced photocatalytic activity of CeO2/Fe-doped InVO4 composite. Furthermore, the possible enhanced photocatalytic mechanism

Transformation of pristine and citrate-functionalized CeO2 nanoparticles in a laboratory-scale activated sludge reactor.

PubMed

Barton, Lauren E; Auffan, Melanie; Bertrand, Marie; Barakat, Mohamed; Santaella, Catherine; Masion, Armand; Borschneck, Daniel; Olivi, Luca; Roche, Nicolas; Wiesner, Mark R; Bottero, Jean-Yves

2014-07-01

Engineered nanomaterials (ENMs) are used to enhance the properties of many manufactured products and technologies. Increased use of ENMs will inevitably lead to their release into the environment. An important route of exposure is through the waste stream, where ENMs will enter wastewater treatment plants (WWTPs), undergo transformations, and be discharged with treated effluent or biosolids. To better understand the fate of a common ENM in WWTPs, experiments with laboratory-scale activated sludge reactors and pristine and citrate-functionalized CeO2 nanoparticles (NPs) were conducted. Greater than 90% of the CeO2 introduced was observed to associate with biosolids. This association was accompanied by reduction of the Ce(IV) NPs to Ce(III). After 5 weeks in the reactor, 44 ± 4% reduction was observed for the pristine NPs and 31 ± 3% for the citrate-functionalized NPs, illustrating surface functionality dependence. Thermodynamic arguments suggest that the likely Ce(III) phase generated would be Ce2S3. This study indicates that the majority of CeO2 NPs (>90% by mass) entering WWTPs will be associated with the solid phase, and a significant portion will be present as Ce(III). At maximum, 10% of the CeO2 will remain in the effluent and be discharged as a Ce(IV) phase, governed by cerianite (CeO2).

CEO summit, Part 3. Loading the ark.

PubMed

Howe, G E; Peddie, E C; Eales, H P; Swedish, J; Chapman, T W; Clay, P; Gaintner, J R

1996-03-20

There's a flood of change coming, and health care executives are quickly building and loading big boats to sail to the future. But what do you take--and what do you leave behind? What will be needed in the new world--and what won't? In the third of an exclusive four-part series planned by McManis Associates and co-sponsored by Hospitals & Health Networks, some top CEOs talk about their travel plans.

Comparing fixed and variable-width Gaussian networks.

PubMed

Kůrková, Věra; Kainen, Paul C

2014-09-01

The role of width of Gaussians in two types of computational models is investigated: Gaussian radial-basis-functions (RBFs) where both widths and centers vary and Gaussian kernel networks which have fixed widths but varying centers. The effect of width on functional equivalence, universal approximation property, and form of norms in reproducing kernel Hilbert spaces (RKHS) is explored. It is proven that if two Gaussian RBF networks have the same input-output functions, then they must have the same numbers of units with the same centers and widths. Further, it is shown that while sets of input-output functions of Gaussian kernel networks with two different widths are disjoint, each such set is large enough to be a universal approximator. Embedding of RKHSs induced by "flatter" Gaussians into RKHSs induced by "sharper" Gaussians is described and growth of the ratios of norms on these spaces with increasing input dimension is estimated. Finally, large sets of argminima of error functionals in sets of input-output functions of Gaussian RBFs are described. Copyright © 2014 Elsevier Ltd. All rights reserved.

Conditional and unconditional Gaussian quantum dynamics

NASA Astrophysics Data System (ADS)

Genoni, Marco G.; Lami, Ludovico; Serafini, Alessio

2016-07-01

This article focuses on the general theory of open quantum systems in the Gaussian regime and explores a number of diverse ramifications and consequences of the theory. We shall first introduce the Gaussian framework in its full generality, including a classification of Gaussian (also known as 'general-dyne') quantum measurements. In doing so, we will give a compact proof for the parametrisation of the most general Gaussian completely positive map, which we believe to be missing in the existing literature. We will then move on to consider the linear coupling with a white noise bath, and derive the diffusion equations that describe the evolution of Gaussian states under such circumstances. Starting from these equations, we outline a constructive method to derive general master equations that apply outside the Gaussian regime. Next, we include the general-dyne monitoring of the environmental degrees of freedom and recover the Riccati equation for the conditional evolution of Gaussian states. Our derivation relies exclusively on the standard quantum mechanical update of the system state, through the evaluation of Gaussian overlaps. The parametrisation of the conditional dynamics we obtain is novel and, at variance with existing alternatives, directly ties in to physical detection schemes. We conclude our study with two examples of conditional dynamics that can be dealt with conveniently through our formalism, demonstrating how monitoring can suppress the noise in optical parametric processes as well as stabilise systems subject to diffusive scattering.

Self-accelerating parabolic beams in quadratic nonlinear media

NASA Astrophysics Data System (ADS)

Dolev, Ido; Libster, Ana; Arie, Ady

2012-09-01

We present experimental observation of self-accelerating parabolic beams in quadratic nonlinear media. We show that the intensity peaks of the first and second harmonics are asynchronous with respect to one another in the two transverse coordinates. In addition, the two coupled harmonics have the same acceleration within and after the nonlinear medium. We also study the evolution of second harmonic accelerating beams inside the quadratic media and their correlation with theoretical beams.

Ceo2 Based Catalysts for the Treatment of Propylene in Motorcycle’s Exhaust Gases

PubMed Central

Pham, Phuong Thi Mai; Le Minh, Thang; Nguyen, Tien The; Van Driessche, Isabel

2014-01-01

In this work, the catalytic activities of several single metallic oxides were studied for the treatment of propylene, a component in motorcycles’ exhaust gases, under oxygen deficient conditions. Amongst them, CeO2 is one of the materials that exhibit the highest activity for the oxidation of C3H6. Therefore, several mixtures of CeO2 with other oxides (SnO2, ZrO2, Co3O4) were tested to investigate the changes in catalytic activity (both propylene conversion and CO2 selectivity). Ce0.9Zr0.1O2, Ce0.8Zr0.2O2 solid solutions and the mixtures of CeO2 and Co3O4 was shown to exhibit the highest propylene conversion and CO2 selectivity. They also exhibited good activities when tested under oxygen sufficient and excess conditions and with the presence of co-existing gases (CO, H2O). PMID:28788253

Binary Inspiral in Quadratic Gravity

NASA Astrophysics Data System (ADS)

Yagi, Kent

2015-01-01

Quadratic gravity is a general class of quantum-gravity-inspired theories, where the Einstein-Hilbert action is extended through the addition of all terms quadratic in the curvature tensor coupled to a scalar field. In this article, we focus on the scalar Gauss- Bonnet (sGB) theory and consider the black hole binary inspiral in this theory. By applying the post-Newtonian (PN) formalism, we found that there is a scalar dipole radiation which leads to -1PN correction in the energy flux relative to gravitational radiation in general relativity. From the orbital decay rate of a low-mass X-ray binary A0600-20, we obtain the bound that is six orders of magnitude stronger than the current solar system bound. Furthermore, we show that the excess in the orbital decay rate of XTE J1118+480 can be explained by the scalar radiation in sGB theory.

JCAHO gets lukewarm reviews from its CEO opinion survey.

PubMed

Koska, M T

1990-05-05

CEOs from 923 hospitals gave the JCAHO mixed reviews in a recent survey: 38 percent thought JCAHO's performance had improved over the past five years; 26 percent thought it had worsened; and 27 percent saw no change. Depending upon who you talk to, the results are either good or bad.

Tangent Lines without Derivatives for Quadratic and Cubic Equations

ERIC Educational Resources Information Center

Carroll, William J.

2009-01-01

In the quadratic equation, y = ax[superscript 2] + bx + c, the equation y = bx + c is identified as the equation of the line tangent to the parabola at its y-intercept. This is extended to give a convenient method of graphing tangent lines at any point on the graph of a quadratic or a cubic equation. (Contains 5 figures.)

Sketching the General Quadratic Equation Using Dynamic Geometry Software

ERIC Educational Resources Information Center

Stols, G. H.

2005-01-01

This paper explores a geometrical way to sketch graphs of the general quadratic in two variables with Geometer's Sketchpad. To do this, a geometric procedure as described by De Temple is used, bearing in mind that this general quadratic equation (1) represents all the possible conics (conics sections), and the fact that five points (no three of…

CeO2 /Bi2 WO6 Heterostructured Microsphere with Excellent Visible-light-driven Photocatalytic Performance for Degradation of Tetracycline Hydrochloride.

PubMed

Zhang, Fengjun; Zou, Shuang; Wang, Tianye; Shi, Yuxi; Liu, Peng

2017-10-01

CeO 2 /Bi 2 WO 6 heterostructured microsphere with excellent and stable photocatalytic activity for degradation tetracyclines was successfully synthesized via a facile solvothermal route. The photocatalytic experiments indicated that CeO 2 /Bi 2 WO 6 heterostructured microspheres exhibited enhanced photocatalytic activity compared to pure Bi 2 WO 6 in both the degradation of tetracycline hydrochloride (TCH) and rhodamine B (RhB) under visible-light irradiation. The 1CeO 2 /2Bi 2 WO 6 exhibited the best photocatalytic activity for degradation of TCH, reaching 91% after 60 min reaction. The results suggested that the particular morphological conformation of the microspheres resulted in smaller size and more uniform morphology so as to increase the specific surface area. Meanwhile, the heterojunction was formed by coupling CeO 2 and Bi 2 WO 6 in the as-prepared microspheres, so that the separation efficiency of photogenerated electrons and holes was dramatically improved and the lifetimes of charge carriers were prolonged. Hence, introduction of CeO 2 could significantly enhance the photocatalytic activity of CeO 2 /Bi 2 WO 6 heterostructured microspheres and facilitate the degradation of TCH. This work provided not only a principle method to synthesize CeO 2 /Bi 2 WO 6 with the excellent photocatalytic performance for actual produce, but also a excellent property of the photocatalyst for potential application in photocatalytic treatment of tetracyclines wastewater from pharmaceutical factory. © 2017 The American Society of Photobiology.

Full-wave generalizations of the fundamental Gaussian beam.

PubMed

Seshadri, S R

2009-12-01

The basic full wave corresponding to the fundamental Gaussian beam was discovered for the outwardly propagating wave in a half-space by the introduction of a source in the complex space. There is a class of extended full waves all of which reduce to the same fundamental Gaussian beam in the appropriate limit. For the extended full Gaussian waves that include the basic full Gaussian wave as a special case, the sources are in the complex space on different planes transverse to the propagation direction. The sources are cylindrically symmetric Gaussian distributions centered at the origin of the transverse planes, the axis of symmetry being the propagation direction. For the special case of the basic full Gaussian wave, the source is a point source. The radiation intensity of the extended full Gaussian waves is determined and their characteristics are discussed and compared with those of the fundamental Gaussian beam. The extended full Gaussian waves are also obtained for the oppositely propagating outwardly directed waves in the second half-space. The radiation intensity distributions in the two half-spaces have reflection symmetry about the midplane. The radiation intensity distributions of the various extended full Gaussian waves are not significantly different. The power carried by the extended full Gaussian waves is evaluated and compared with that of the fundamental Gaussian beam.

Rational design of octahedron and nanowire CeO2@MnO2 core-shell heterostructures with outstanding rate capability for asymmetric supercapacitors.

PubMed

Zhu, Shi Jin; Jia, Jia Qi; Wang, Tian; Zhao, Dong; Yang, Jian; Dong, Fan; Shang, Zheng Guo; Zhang, Yu Xin

2015-10-14

Two kinds of novel CeO2@MnO2 nanostructures have been synthesized via a self-assembly strategy. The as-prepared CeO2 nanowire@MnO2 nanostructures exhibited unprecedented pseudocapacitance performance (255 F g(-1)) with outstanding rate capability. A new mechanism based on the synergistic effect between CeO2 and MnO2 was proposed to interpret this phenomenon. When assembled as an asymmetric supercapacitor, an energy density of 27.5 W h kg(-1) with a maximum power density of 1.6 kW kg(-1) was achieved for CeO2 nanowire@MnO2 nanostructures.

Improved Gaussian Beam-Scattering Algorithm

NASA Technical Reports Server (NTRS)

Lock, James A.

1995-01-01

The localized model of the beam-shape coefficients for Gaussian beam-scattering theory by a spherical particle provides a great simplification in the numerical implementation of the theory. We derive an alternative form for the localized coefficients that is more convenient for computer computations and that provides physical insight into the details of the scattering process. We construct a FORTRAN program for Gaussian beam scattering with the localized model and compare its computer run time on a personal computer with that of a traditional Mie scattering program and with three other published methods for computing Gaussian beam scattering. We show that the analytical form of the beam-shape coefficients makes evident the fact that the excitation rate of morphology-dependent resonances is greatly enhanced for far off-axis incidence of the Gaussian beam.

Electronic, magnetic and optical properties of C- and N-doped CeO2 bulk and (111) surface from first-principles

NASA Astrophysics Data System (ADS)

Dai, Shuhua; Zhou, Wei; Liu, Yanyu; Lu, Yi-Lin; Sun, Lili; Wu, Ping

2018-05-01

The electronic, magnetic and optical properties of C- and N-doped CeO2 bulk and (111) surface have been systematically investigated by first-principles calculations. The results show that the spin splitting occurs when doping atoms replace the anion sites in the CeO2 matrix, causing a local magnetic moment of 2.00, and 1.00 μB for C- and N-doping, respectively. The strong hybridization between dopants 2p and O 2p triplet-states around the Fermi level gives rise to the half-metallic character for doped bulk systems, while substitution onto the surface eliminates the degeneration of dopants 2p orbitals, which results in anisotropic spin atmosphere. Especially, owing to the low formation energy and available RTFM, N-doped CeO2 would be easily realized in the experiment and should also be wonderful candidate materials for oxide spintronics. In addition, compared with N-doped CeO2, the calculated optical properties reveal that C-doped CeO2 (111) surface is able to enhance the absorption of the visible light.

Solid state speciation of uranium and its local structure in Sr2CeO4 using photoluminescence spectroscopy

NASA Astrophysics Data System (ADS)

Sahu, M.; Gupta, Santosh K.; Jain, D.; Saxena, M. K.; Kadam, R. M.

2018-04-01

An effort was taken to carry our speciation study of uranium ion in technologically important cerate host Sr2CeO4 using time resolved photoluminescence spectroscopy. Such studies are not relevant only to nuclear industry but can give rich insight into fundamentals of 5f electron chemistry in solid state systems. In this work both undoped and varied amount of uranium doped Sr2CeO4 compound is synthesized using complex polymerization method and is characterized systematically using X-ray diffraction (XRD), Raman spectroscopy, photoluminescence spectroscopy and scanning electron microscopy (SEM). Both XRD and Raman spectroscopy confirmed the formation of pure Sr2CeO4 which has tendency to decompose peritectically to SrCeO3 and SrO at higher temperature. Uranium doping is confirmed by XRD. Uranium exhibits a rich chemistry owing to its variable oxidation state from +3 to +6. Each of them exhibits distinct luminescence properties either due to f-f transitions or ligand to metal charge transfer (LMCT). We have taken Sr2CeO4 as a model host lattice to understand the photophysical characteristics of uranium ion in it. Emission spectroscopy revealed the stabilization of uranium as U (VI) in the form of UO66- (octahedral uranate) in Sr2CeO4. Emission kinetics study reflects that uranate ions are not homogeneously distributed in Sr2CeO4 and it has two different environments due to its stabilization at both Sr2+ as well as Ce4+ site. The lifetime population analysis interestingly pinpointed that majority of uranate ion resided at Ce4+ site. The critical energy-transfer distance between the uranate ion was determined based on which the concentration quenching mechanism was attributed to electric multipolar interaction. These studies are very important in designing Sr2CeO4 based optoelectronic material as well exploring it for actinides studies.

Solid state speciation of uranium and its local structure in Sr2CeO4 using photoluminescence spectroscopy.

PubMed

Sahu, M; Gupta, Santosh K; Jain, D; Saxena, M K; Kadam, R M

2018-04-15

An effort was taken to carry our speciation study of uranium ion in technologically important cerate host Sr 2 CeO 4 using time resolved photoluminescence spectroscopy. Such studies are not relevant only to nuclear industry but can give rich insight into fundamentals of 5f electron chemistry in solid state systems. In this work both undoped and varied amount of uranium doped Sr 2 CeO 4 compound is synthesized using complex polymerization method and is characterized systematically using X-ray diffraction (XRD), Raman spectroscopy, impedance spectroscopy and scanning electron microscopy (SEM). Both XRD and Raman spectroscopy confirmed the formation of pure Sr 2 CeO 4 which has tendency to decompose peritectically to SrCeO 3 and SrO at higher temperature. Uranium doping is confirmed by XRD. Uranium exhibits a rich chemistry owing to its variable oxidation state from +3 to +6. Each of them exhibits distinct luminescence properties either due to f-f transitions or ligand to metal charge transfer (LMCT). We have taken Sr 2 CeO 4 as a model host lattice to understand the photophysical characteristics of uranium ion in it. Emission spectroscopy revealed the stabilization of uranium as U (VI) in the form of UO 6 6- (octahedral uranate) in Sr 2 CeO 4 . Emission kinetics study reflects that uranate ions are not homogeneously distributed in Sr 2 CeO 4 and it has two different environments due to its stabilization at both Sr 2+ as well as Ce 4+ site. The lifetime population analysis interestingly pinpointed that majority of uranate ion resided at Ce 4+ site. The critical energy-transfer distance between the uranate ion was determined based on which the concentration quenching mechanism was attributed to electric multipolar interaction. These studies are very important in designing Sr 2 CeO 4 based optoelectronic material as well exploring it for actinides studies. Copyright © 2018 Elsevier B.V. All rights reserved.

Symmetric quadratic Hamiltonians with pseudo-Hermitian matrix representation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernández, Francisco M., E-mail: fernande@quimica.unlp.edu.ar

2016-06-15

We prove that any symmetric Hamiltonian that is a quadratic function of the coordinates and momenta has a pseudo-Hermitian adjoint or regular matrix representation. The eigenvalues of the latter matrix are the natural frequencies of the Hamiltonian operator. When all the eigenvalues of the matrix are real, then the spectrum of the symmetric Hamiltonian is real and the operator is Hermitian. As illustrative examples we choose the quadratic Hamiltonians that model a pair of coupled resonators with balanced gain and loss, the electromagnetic self-force on an oscillating charged particle and an active LRC circuit. -- Highlights: •Symmetric quadratic operators aremore » useful models for many physical applications. •Any such operator exhibits a pseudo-Hermitian matrix representation. •Its eigenvalues are the natural frequencies of the Hamiltonian operator. •The eigenvalues may be real or complex and describe a phase transition.« less

An Evaluation of the Potential Phototoxicity of CeO2 Nanoparticles in Retinal Pigment Epithelial Cells in-vitro

EPA Science Inventory

Cerium dioxide (CeO2) engineered nanoparticles (NP) are used as fuel-borne catalysts in off-road diesel engines, which can lead to exhaust emissions of respirable CeO2 NP. Other metal oxides may act as photo-catalysts which induce the generation of free radicals upon exposure to ...

In situ DRIFTS investigation of NH3-SCR reaction over CeO2/zirconium phosphate catalyst

NASA Astrophysics Data System (ADS)

Zhang, Qiulin; Fan, Jie; Ning, Ping; Song, Zhongxian; Liu, Xin; Wang, Lanying; Wang, Jing; Wang, Huimin; Long, Kaixian

2018-03-01

A series of ceria modified zirconium phosphate catalysts were synthesized for selective catalytic reduction of NO with ammonia (NH3-SCR). Over 98% NOx conversion and 98% N2 selectivity were obtained by the CeO2/ZrP catalyst with 20 wt.% CeO2 loading at 250-425 °C. The interaction between CeO2 and zirconium phosphate enhanced the redox abilities and surface acidities of the catalysts, resulting in the improvement of NH3-SCR activity. The in situ DRIFTS results indicated that the NH3-SCR reaction over the catalysts followed both Eley-Rideal and Langmuir-Hinshelwood mechanisms. The amide (sbnd NH2) groups and the NH4+ bonded to Brønsted acid sites were the important intermediates of Eley-Rideal mechanism.

Effect of the Cerium Oxide (CeO2) on the Structural and Electrochemical Properties of the LaNi5Ce Metal Hydride Anode

NASA Astrophysics Data System (ADS)

Utami Hapsari, Ade; Zulfia, Anne; Raharjo, Jarot; Agustanhakri

2017-07-01

One of negative electrode, AB5-type alloy electrodes, have been extensively studied and applied in rechargeable Ni-MH batteries due to their excellent electrochemical characteristics. Some researchers have found that addition of rare earth oxides (La, Ce, Pr, Er, Tm, Yb) to AB5-type alloy (MH) electrode improves battery performance significantly. Cerium Oxide (CeO2) is a light rare earth oxide is widely obtained from the processing of tailings in mining activities. During this time, there is still little data for research applications of cerium oxide for electrode materials. In this paper, the effects of adding CeO2 on the performance metal hydride electrode were investigated. In order to study the effects of CeO2 on the performance of anode material, 1%, 2%, and 3% of weight ratio CeO2 was mixed to LaNi5 as an negative electrode. The powder mixtures were mechanically milled at a speed of rpm 240 for 2 hours using ball mill. The powder mixtures were characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM). Electrochemical characteristics were measured using electrochemical impedance spectroscopy (EIS). The powder mixing showed the presence of Ce atom substitution into LaNi5 structures that affect the electrochemical properties of the material. The addition of cerium oxide at LaNi5 increase of the value of impedance. However, the addition of the value of impedance at 1% CeO2 is not significant when compared with the addition of 2% and 3% CeO2 that actually make the electrochemical properties of LaNi5 worst. Although the addition of 1% CeO2 also slightly increases the impedance value of LaNi5, but the addition of 1% CeO2 showed increase the corrosion resistance than without the addition of CeO2 and the addition of 2% and 3% CeO2.

Gaussian pre-filtering for uncertainty minimization in digital image correlation using numerically-designed speckle patterns

NASA Astrophysics Data System (ADS)

Mazzoleni, Paolo; Matta, Fabio; Zappa, Emanuele; Sutton, Michael A.; Cigada, Alfredo

2015-03-01

This paper discusses the effect of pre-processing image blurring on the uncertainty of two-dimensional digital image correlation (DIC) measurements for the specific case of numerically-designed speckle patterns having particles with well-defined and consistent shape, size and spacing. Such patterns are more suitable for large measurement surfaces on large-scale specimens than traditional spray-painted random patterns without well-defined particles. The methodology consists of numerical simulations where Gaussian digital filters with varying standard deviation are applied to a reference speckle pattern. To simplify the pattern application process for large areas and increase contrast to reduce measurement uncertainty, the speckle shape, mean size and on-center spacing were selected to be representative of numerically-designed patterns that can be applied on large surfaces through different techniques (e.g., spray-painting through stencils). Such 'designer patterns' are characterized by well-defined regions of non-zero frequency content and non-zero peaks, and are fundamentally different from typical spray-painted patterns whose frequency content exhibits near-zero peaks. The effect of blurring filters is examined for constant, linear, quadratic and cubic displacement fields. Maximum strains between ±250 and ±20,000 με are simulated, thus covering a relevant range for structural materials subjected to service and ultimate stresses. The robustness of the simulation procedure is verified experimentally using a physical speckle pattern subjected to constant displacements. The stability of the relation between standard deviation of the Gaussian filter and measurement uncertainty is assessed for linear displacement fields at varying image noise levels, subset size, and frequency content of the speckle pattern. It is shown that bias error as well as measurement uncertainty are minimized through Gaussian pre-filtering. This finding does not apply to typical spray

Gaussian or non-Gaussian logconductivity distribution at the MADE site: What is its impact on the breakthrough curve?

PubMed

Fiori, Aldo; Volpi, Elena; Zarlenga, Antonio; Bohling, Geoffrey C

2015-08-01

The impact of the logconductivity (Y=ln K) distribution fY on transport at the MADE site is analyzed. Our principal interest is in non-Gaussian fY characterized by heavier tails than the Gaussian. Both the logconductivity moments and fY itself are inferred, taking advantage of the detailed measurements of Bohling et al. (2012). The resulting logconductivity distribution displays heavier tails than the Gaussian, although the departure from Gaussianity is not significant. The effect of the logconductivity distribution on the breakthrough curve (BTC) is studied through an analytical, physically based model. It is found that the non-Gaussianity of the MADE logconductivity distribution does not strongly affect the BTC. Counterintuitively, assuming heavier tailed distributions for Y, with same variance, leads to BTCs which are more symmetrical than those for the Gaussian fY, with less pronounced preferential flow. Results indicate that the impact of strongly non-Gaussian, heavy tailed distributions on solute transport in heterogeneous porous formations can be significant, especially in the presence of high heterogeneity, resulting in reduced preferential flow and retarded peak arrivals. Copyright © 2015 Elsevier B.V. All rights reserved.

Non-Gaussianity from isocurvature perturbations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawasaki, Masahiro; Nakayama, Kazunori; Sekiguchi, Toyokazu

2008-11-15

We develop a formalism for studying non-Gaussianity in both curvature and isocurvature perturbations. It is shown that non-Gaussianity in the isocurvature perturbation between dark matter and photons leaves distinct signatures in the cosmic microwave background temperature fluctuations, which may be confirmed in future experiments, or possibly even in the currently available observational data. As an explicit example, we consider the quantum chromodynamics axion and show that it can actually induce sizable non-Gaussianity for the inflationary scale, H{sub inf} = O(10{sup 9}-10{sup 11}) GeV.

Biochemical effects of six TiO2 and four CeO2 nanomaterials in HepG2 cells

EPA Science Inventory

Biochemical effects of six TiO2 and four CeO2 nanomaterials in HepG2 cellsBecause of their growing number of uses, nanoparticles composed of CeO2 (cosmetics, polishing materials and automotive fuel additives) and TiO2 (pigments, sunscreens and photocatalysts) are of particular to...

Recent advances in scalable non-Gaussian geostatistics: The generalized sub-Gaussian model

NASA Astrophysics Data System (ADS)

Guadagnini, Alberto; Riva, Monica; Neuman, Shlomo P.

2018-07-01

Geostatistical analysis has been introduced over half a century ago to allow quantifying seemingly random spatial variations in earth quantities such as rock mineral content or permeability. The traditional approach has been to view such quantities as multivariate Gaussian random functions characterized by one or a few well-defined spatial correlation scales. There is, however, mounting evidence that many spatially varying quantities exhibit non-Gaussian behavior over a multiplicity of scales. The purpose of this minireview is not to paint a broad picture of the subject and its treatment in the literature. Instead, we focus on very recent advances in the recognition and analysis of this ubiquitous phenomenon, which transcends hydrology and the Earth sciences, brought about largely by our own work. In particular, we use porosity data from a deep borehole to illustrate typical aspects of such scalable non-Gaussian behavior, describe a very recent theoretical model that (for the first time) captures all these behavioral aspects in a comprehensive manner, show how this allows generating random realizations of the quantity conditional on sampled values, point toward ways of incorporating scalable non-Gaussian behavior in hydrologic analysis, highlight the significance of doing so, and list open questions requiring further research.

Irradiation effects in UO2 and CeO2

NASA Astrophysics Data System (ADS)

Ye, Bei; Oaks, Aaron; Kirk, Mark; Yun, Di; Chen, Wei-Ying; Holtzman, Benjamin; Stubbins, James F.

2013-10-01

Single crystal CeO2, as a surrogate material to UO2, was irradiated with 500 keV xenon ions at 800 °C while being observed using in situ transmission electron microscopy (TEM). Experimental results show the formation and growth of defect clusters including dislocation loops and cavities as a function of increasing atomic displacement dose. At high dose, the dislocation loop structure evolves into an extended dislocation line structure, which appears to remain stable to the high dose levels examined in this study. A high concentration of cavities was also present in the microstructure. Despite high atomic displacement doses, the specimen remained crystalline to a cumulated dose of 5 × 1015 ions/cm2, which is consistent with the known stability of the fluorite structure under high dose irradiation. Kinetic Monte Carlo calculations show that oxygen mobility is substantially higher in hypo-stoichiometric UO2/CeO2 than hyper-stoichiometric systems. This result is consistent with the ability of irradiation damage to recover even at intermediate irradiation temperatures.

CO2 methanation on the catalyst of Ni/MCM-41 promoted with CeO2.

PubMed

Wang, Xiaoliu; Zhu, Lingjun; Liu, Yincong; Wang, Shurong

2018-06-01

CO 2 as a raw feed combined with renewable hydrogen for the production of useful chemicals and alternative energy products is one of the solutions to environmental and energy problems. In this study, a series of Ni-xCeO 2 /MCM-41 catalysts with a nickel content of 20wt% were prepared through deposition precipitation method for CO 2 methanation. Different characterization methods, including BET, XRD, TEM, SEM, H 2 -TPR and H 2 -TPD were applied to help explore the influence mechanism of CeO 2 on Ni/MCM-41 in CO 2 methanation. It was found that all CeO 2 -promoted catalysts exhibited enhanced catalytic activity when compared to Ni/MCM-41. The catalyst modified with 20wt% CeO 2 showed the best catalytic performance, with CO 2 conversion and CH 4 selectivity of 85.6% and 99.8%, respectively, at the temperature of 380°C under atmospheric pressure. The synergetic effects among Ni 0 active sites, the promoter and the support, including nickel dispersion improvement and increased CO 2 adsorption sites due to the addition of CeO 2 , were considered as important factors for high reactivity of the promoted catalysts. The stability test showed that the promoted catalyst maintained its high reactivity after 30h. Copyright © 2017 Elsevier B.V. All rights reserved.

Electromagnetic tracking system with reduced distortion using quadratic excitation.

PubMed

Bien, Tomasz; Li, Mengfei; Salah, Zein; Rose, Georg

2014-03-01

Electromagnetic tracking systems, frequently used in minimally invasive surgery, are affected by conductive distorters. The influence of conductive distorters on electromagnetic tracking system accuracy can be reduced through magnetic field modifications. This approach was developed and tested. The voltage induced directly by the emitting coil in the sensing coil without additional influence by the conductive distorter depends on the first derivative of the voltage on the emitting coil. The voltage which is induced indirectly by the emitting coil across the conductive distorter in the sensing coil, however, depends on the second derivative of the voltage on the emitting coil. The electromagnetic tracking system takes advantage of this difference by supplying the emitting coil with a quadratic excitation voltage. The method is adaptive relative to the amount of distortion cause by the conductive distorters. This approach is evaluated with an experimental setup of the electromagnetic tracking system. In vitro testing showed that the maximal error decreased from 10.9 to 3.8 mm when the quadratic voltage was used to excite the emitting coil instead of the sinusoidal voltage. Furthermore, the root mean square error in the proximity of the aluminum disk used as a conductive distorter was reduced from 3.5 to 1.6 mm when the electromagnetic tracking system used the quadratic instead of sinusoidal excitation. Electromagnetic tracking with quadratic excitation is immune to the effects of a conductive distorter, especially compared with sinusoidal excitation of the emitting coil. Quadratic excitation of electromagnetic tracking for computer-assisted surgery is promising for clinical applications.

Online Quadrat Study - Site Index

Science.gov Websites

Study Project - Prairie Advocates Project ) Background Information - Data Collection and Entry - Data Data Entry Data Summaries and Graphs Quadrat Study Poster for your classroom. Directions for Looking at by Prairie Study Prairie Experts For Non-Fermilab Prairie researchers: Complete step-by-step

Remote Sensing Education and Development Countries: Multilateral Efforts through the Committee on Earth Observation Satellites (CEOS)

NASA Technical Reports Server (NTRS)

Charles, Leslie Bermann

1998-01-01

The Committee on Earth Observation Satellites (CEOS) is an international organization which coordinates space-based Earth observations world wide. Created in 1984, CEOS now comprises 38 national space agencies, regional organizations and international space-related and research groups. The aim of CEOS is to achieve international coordination in the planning of satellite missions for Earth observation and to maximize the utilization of data from these missions world-wide. With regard to developing countries, the fundamental aim of CEOS is to encourage the creation and maintenance of indigenous capability that is integrated into the local decision-making process, thereby enabling developing countries to obtain the maximum benefit from Earth observation. Obtaining adequate access to remote sensing information is difficult for developing countries and students and teachers alike. High unit data prices, the specialized nature of the technology , difficulty in locating specific data, complexities of copyright provisions, the emphasis on "leading edge" technology and research, and the lack of training materials relating to readily understood application are frequently noted obstacles. CEOS has developed an education CD-ROM which is aimed at increasing the integration of space-based data into school curricula, meeting the heretofore unsatisfied needs of developing countries for information about Earth observation application, data sources and future plans; and raising awareness around the world of the value of Earth observation data from space. The CD-ROM is designed to be used with an Internet web browser, increasing the information available to the user, but it can also be used on a stand-alone machine. It contains suggested lesson plans and additional resources for educators and users in developing countries.

Synthesis and characterization of reduced graphene oxide decorated with CeO2-doped MnO2 nanorods for supercapacitor applications.

PubMed

Ojha, Gunendra Prasad; Pant, Bishweshwar; Park, Soo-Jin; Park, Mira; Kim, Hak-Yong

2017-05-15

A novel and efficient CeO 2 -doped MnO 2 nanorods decorated reduced graphene oxide (CeO 2 -MnO 2 /RGO) nanocomposite was successfully synthesized via hydrothermal method. The growth of the CeO 2 doped MnO 2 nanorods over GO sheets and reduction of GO were simultaneously carried out under hydrothermal treatment. The morphology and structure of as-synthesized nanocomposite were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy, which revealed the formation of CeO 2 -MnO 2 decorated RGO nanocomposites. The electrochemical performance of as-prepared CeO 2 -MnO 2 /RGO nanocomposites as an active electrode material for supercapacitor was evaluated by cyclic voltammetry, charge-discharge, and electrochemical impedance spectroscopy (EIS) methods in 2M alkaline medium. The obtained results revealed that as-synthesized CeO 2 -MnO 2 /RGO nanocomposite exhibited higher specific capacitance (648F/g) as compared to other formulations (MnO 2 /RGO nanocomposites: 315.13 F/g and MnO 2 nanorods: 228.5 F/g) at the scan rate of 5mV/s. After 1000 cycles, it retained ∼90.4%, exhibiting a good stability. The high surface area, enhanced electrical conductivity, and good stability possess by the nanocomposite make this material a promising candidate to be applied as a supercapacitor electrode. Copyright © 2017 Elsevier Inc. All rights reserved.

High-Performance Ru1 /CeO2 Single-Atom Catalyst for CO Oxidation: A Computational Exploration.

PubMed

Li, Fengyu; Li, Lei; Liu, Xinying; Zeng, Xiao Cheng; Chen, Zhongfang

2016-10-18

By means of density functional theory computations, we examine the stability and CO oxidation activity of single Ru on CeO 2 (111), TiO 2 (110) and Al 2 O 3 (001) surfaces. The heterogeneous system Ru 1 /CeO 2 has very high stability, as indicated by the strong binding energies and high diffusion barriers of a single Ru atom on the ceria support, while the Ru atom is rather mobile on TiO 2 (110) and Al 2 O 3 (001) surfaces and tends to form clusters, excluding these systems from having a high efficiency per Ru atom. The Ru 1 /CeO 2 exhibits good catalytic activity for CO oxidation via the Langmuir-Hinshelwood mechanism, thus is a promising single-atom catalyst. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gaussian mass optimization for kernel PCA parameters

NASA Astrophysics Data System (ADS)

Liu, Yong; Wang, Zulin

2011-10-01

This paper proposes a novel kernel parameter optimization method based on Gaussian mass, which aims to overcome the current brute force parameter optimization method in a heuristic way. Generally speaking, the choice of kernel parameter should be tightly related to the target objects while the variance between the samples, the most commonly used kernel parameter, doesn't possess much features of the target, which gives birth to Gaussian mass. Gaussian mass defined in this paper has the property of the invariance of rotation and translation and is capable of depicting the edge, topology and shape information. Simulation results show that Gaussian mass leads a promising heuristic optimization boost up for kernel method. In MNIST handwriting database, the recognition rate improves by 1.6% compared with common kernel method without Gaussian mass optimization. Several promising other directions which Gaussian mass might help are also proposed at the end of the paper.

Comparison of Gaussian and non-Gaussian Atmospheric Profile Retrievals from Satellite Microwave Data

NASA Astrophysics Data System (ADS)

Kliewer, A.; Forsythe, J. M.; Fletcher, S. J.; Jones, A. S.

2017-12-01

The Cooperative Institute for Research in the Atmosphere at Colorado State University has recently developed two different versions of a mixed-distribution (lognormal combined with a Gaussian) based microwave temperature and mixing ratio retrieval system as well as the original Gaussian-based approach. These retrieval systems are based upon 1DVAR theory but have been adapted to use different descriptive statistics of the lognormal distribution to minimize the background errors. The input radiance data is from the AMSU-A and MHS instruments on the NOAA series of spacecraft. To help illustrate how the three retrievals are affected by the change in the distribution we are in the process of creating a new website to show the output from the different retrievals. Here we present initial results from different dynamical situations to show how the tool could be used by forecasters as well as for educators. However, as the new retrieved values are from a non-Gaussian based 1DVAR then they will display non-Gaussian behaviors that need to pass a quality control measure that is consistent with this distribution, and these new measures are presented here along with initial results for checking the retrievals.

Construction of g-C3N4/CeO2/ZnO ternary photocatalysts with enhanced photocatalytic performance

NASA Astrophysics Data System (ADS)

Yuan, Yuan; Huang, Gui-Fang; Hu, Wang-Yu; Xiong, Dan-Ni; Zhou, Bing-Xin; Chang, Shengli; Huang, Wei-Qing

2017-07-01

Promoting the spatial separation of photoexcited charge carriers is of paramount significance for photocatalysis. In this work, binary g-C3N4/CeO2 nanosheets are first prepared by pyrolysis and subsequent exfoliation method, then decorated with ZnO nanoparticles to construct g-C3N4/CeO2/ZnO ternary nanocomposites with multi-heterointerfaces. Notably, the type-II staggered band alignments existing between any two of the constituents, as well as the efficient three-level transfer of electron-holes in unique g-C3N4/CeO2/ZnO ternary composites, leads to the robust separation of photoexcited charge carriers, as verified by its photocurrent increased by 8 times under visible light irradiation. The resulting g-C3N4/CeO2/ZnO ternary nanocomposites unveil appreciably increased photocatalytic activity, faster than that of pure g-C3N4, ZnO and g-C3N4/CeO2 by a factor of 11, 4.6 and 3.7, respectively, and good stability toward methylene blue (MB) degradation. The remarkably enhanced photocatalytic activity of g-C3N4/CeO2/ZnO ternary heterostructures can be interpreted in terms of lots of active sites of nanosheet shapes and the efficient charge separation owing to the resulting type-II band alignment with more than one heterointerface and the efficient three-level electron-hole transfer. A plausible mechanism is also elucidated via active species trapping experiments with various scavengers, which indicating that the photogenerated holes and •OH radicals play a crucial role in photodegradation reaction under visible light irradiation. This work suggest that the rational design and construction of type II multi-heterostructures is powerful for developing highly efficient and reusable visible-light photocatalysts for environmental purification and energy conversion.

Synthesis and photocatalytic activity of p–n junction CeO2/Co3O4 photocatalyst for the removal of various dyes from wastewater

NASA Astrophysics Data System (ADS)

Tang, Yuanzheng; Zhang, Meng; Wu, Zhengying; Chen, Zhigang; Liu, Chengbao; Lin, Yun; Chen, Feng

2018-04-01

CeO2, Co3O4, and Co3O4/CeO2 composites are successfully synthesized by a simple coprecipitation method. X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) results indicate that the CeO2, Co3O4, and Co3O4/CeO2 precursors sintered at 500 °C has good crystallization. The cerium nitrate introduced into cobalt nitrate precursor solution improved the surface morphology and photocatalytic activity of Co3O4 significantly. The photo-degradation of methylene blue (MB), xylenol orange (XO), methyl orange (MO), and methyl red (MR) catalyzed by prepared nanocomposites were studied under visible light irradiation. Photocatalytic experiment results indicate that the photocatalytic activity of Co3O4/CeO2 composites for degradation of various dyes highly depend on pH value. The optimum conditions for the photocatalytic experiments of Co3O4/CeO2 composites were determined to be as follows: dye concentration, 50 mg L‑1, and catalyst concentration, 50 mg L‑1. The excellent photocatalytic activity of the p–n junction Co3O4/CeO2 composites can be ascribed to the ·O2‑ radicals and h+.

Challenges and Opportunities in Early Childhood: Views of the CEOs of the Big Three--Twenty-First Annual Status Report on For Profit Child Care

ERIC Educational Resources Information Center

Neugebauer, Roger

2008-01-01

This article presents the viewpoints of the CEOs of the three largest for profit child care organizations in North America about trends in their field. The three individuals are: (1) David Lissy, CEO, Bright Horizons Family Solutions; (2) Felicia Thornton, CEO, Knowledge Universe Education, U.S. (parent company for Knowledge Learning Corporation);…

Quadratic elongation: A quantitative measure of distortion in coordination polyhedra

USGS Publications Warehouse

Robinson, Kelly F.; Gibbs, G.V.; Ribbe, P.H.

1971-01-01

Quadratic elongation and the variance of bond angles are linearly correlated for distorted octahedral and tetrahedral coordination complexes, both of which show variations in bond length and bond angle. The quadratic elonga tion is dimensionless, giving a quantitative measure of polyhedral distortion which is independent of the effective size of the polyhedron.

A facile growth process of CeO2-Co3O4 composite nanotubes and its catalytic stability for CO oxidation

NASA Astrophysics Data System (ADS)

Oh, Hyerim; Kim, Il Hee; Lee, Nam-Suk; Dok Kim, Young; Kim, Myung Hwa

2017-08-01

Hybrid cerium dioxide (CeO2)-cobalt oxide (Co3O4) composite nanotubes were successfully prepared by a combination of electrospinning and thermal annealing using CeO2 and Co3O4 precursors for the first time. Electrospun CeO2-Co3O4 composite nanotubes represent relatively porous surface texture with small dimensions between 80 and 150 nm in the outer diameter. The microscopic investigations indicate that the nanoparticle like crystalline structures of CeO2 and Co3O4 are homogenously distributed and continuously connected to form the shape of nanotube in the length of a few micrometers during thermal annealing. It is expected that the different evaporation behaviors of solvents and matrix polymer between the core and the shell in as-spun nanofibers in the course of thermal annealing could be reasonably responsible for the formation of well-defined CeO2/Co3O4 hybrid nanotubes. Additionally, the general catalytic activities of electrospun CeO2/Co3O4 hybrid nanotubes toward the oxidation of carbon monoxide (CO) were carefully examined by a continuous flow system, resulting in favorable catalytic activity as well as catalytic stability for CO oxidation between 150 °C and 200 °C without the deactivation of the catalyst with time stems from accumulation of reaction intermediates such as carbonate species.

The effects of physicochemical properties of CeO2 nanoparticles on toxicity to soil denitrification processes

NASA Astrophysics Data System (ADS)

Dahle, Jessica Teague

The studies presented in this thesis identify the impact of NP CeO 2 on soil denitrifying microbial communities and reveal that physical and chemical characteristics including particle size, speciation, concentration, pH, and presence of ligands are key to predicting environmental fate and reactivity of NP CeO2 in the soil. A review of the literature in Chapter 1 revealed a widespread lack of toxicological information for soil exposures to NP CeO2. Soil denitrifying bacteria are a keystone species because they serve an important role in the global nitrogen cycle controlling the atmospheric nitrogen input. Soil denitrifiers are important to this study because the reducing conditions during denitrification could induce phase transformation of Ce(IV) to Ce(III), potentially influencing the toxicity of Ce. Cerium is well known for being the only lanthanide that is thermodynamically stable in both the trivalent and tetravalent state in low temperature geochemical environments. Using well characterized NP Ce(IV)O 2 as well as bulk soluble Ce(III), batch denitrification experiments were conducted to evaluate the toxicity of Ce species to the denitrifying community in a Toccoa sandy loam soil. The statistical analysis on the antimicrobial effect on soil denitrifiers was conducted using both steady-state evaluation and zero-order kinetic models in order to compare the toxicity of the Ce(III) species to the NPs. These studies, presented in Chapter 3, show that soluble Ce(III) is far more toxic than Ce(IV)O2 NPs when an equal total concentration of Ce is used, though both species exhibit toxicity to the denitrifiers via statistically significant inhibition of soil denitrification processes. Particle-size dependent toxicity, species-dependent toxicity, and concentration-dependent toxicity were all observed in this study for both the steady-state and the kinetic evaluations. The possibility of toxicity enhancement and diminishment via dissolution and ligand complexation

Gaussian operations and privacy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Navascues, Miguel; Acin, Antonio

2005-07-15

We consider the possibilities offered by Gaussian states and operations for two honest parties, Alice and Bob, to obtain privacy against a third eavesdropping party, Eve. We first extend the security analysis of the protocol proposed in [Navascues et al. Phys. Rev. Lett. 94, 010502 (2005)]. Then, we prove that a generalized version of this protocol does not allow one to distill a secret key out of bound entangled Gaussian states.

Effects of Classroom Instruction on Students' Understanding of Quadratic Equations

ERIC Educational Resources Information Center

Vaiyavutjamai, Pongchawee; Clements, M. A.

2006-01-01

Two hundred and thirty-one students in six Grade 9 classes in two government secondary schools located near Chiang Mai, Thailand, attempted to solve the same 18 quadratic equations before and after participating in 11 lessons on quadratic equations. Data from the students' written responses to the equations, together with data in the form of…

Which of these people is your future CEO?

PubMed

Groysberg, Boris; Hill, Andrew; Johnson, Toby

2010-11-01

Americans have long believed that U.S. military officers--trained for high-stakes positions, resilience, and mental agility--make excellent CEOs. That belief is sound, but the authors' analysis of the performance of 45 companies led by CEOs with military experience revealed differences in how the branches (Army, Navy, Air Force, Marine Corps) prepare leaders for business. Those differences reflect the trade-off between flexibility and process that each branch of the armed services must make. Army and Marine Corps officers operate in an inherently uncertain environment. They define the mission but then give subordinates the flexibility to adjust to realities on the ground. This leadership experience tends to turn out business executives who excel in small firms, where they can set a goal and then empower others to work toward it. Navy and Air Force officers, who operate expensive, complex systems such as submarines and aircraft carriers, are trained to follow processes to the letter, because even small deviations can have large consequences. In corporations, these leaders excel in regulated industries and in firms that take a process approach to innovation. The larger lesson that the military can offer the business world is that fit matters. Different circumstances demand different leadership skills. Hire the person who fits the job.

Examination of Electric Utility CEO Compensation 2000-2011 and its significance to Company Earnings, Company Revenue, Company Stock and the Dow Jones Utility Average

NASA Astrophysics Data System (ADS)

Labovitch, Andrew

This dissertation examined electric utility CEO compensation during the years 2000 through 2011 for United States owned and operated companies. To determine the extent to which agency theory may apply to electric utility CEO compensation, this examination segmented the industry by four types of company financial metrics: revenue, earnings, stock price and the Dow Jones Utility Average; by five categories of CEO compensation: base salary, bonus, stock grants, all other compensation and total compensation; and by four categories of company size as measured by revenue: large, medium, small and the industry as a whole. Electric utility CEO compensation data was analyzed with the financial metrics to determine correlations. No type of compensation was highly correlated to any of the financial metrics for any size industry segment indicating that there was little agency. CEO compensation in large electric utility companies was higher than compensation in medium and smaller companies even though the CEOs at larger companies earned less per dollar of revenue and per dollar of earnings than their counterparts in smaller companies.

Satellite missions, global environment, and the concept of a global satellite observation information network. The role of the committee on Earth observation satellites (CEOS)

NASA Astrophysics Data System (ADS)

Smith, D. Brent; Williams, David F.; Fujita, Akihiro

The paper traces the development of the Committee on Earth Observation Satellites (CEOS) since its November 1990 Plenary: its restructuring to include major intergovernmental user and international scientific organizational affiliates; its focus on data sharing issues and completion of a CEOS resolution guaranteeing global change researchers access to satellite data at the cost of filling a user request; unfolding of a CEOS-associated initiative of the UK Prime Minister reporting to UNCED delegations on the relevance of satellite missions to the study of the global environment; development of a "Dossier" providing detailed information on all CEOS agency satellite missions, including sensor specifications, ground systems, standard data products, and other information relevant to users; creation of a permanent CEOS Secretariat; and efforts currently underway to assess the feasibility of a global satellite observation information network. Of particular relevance to developing countries, the paper will discuss CEOS efforts to assure broad user access and to foster acceptance of applications in such important areas as disaster monitoring and mitigation, land cover change, weather forecasting, and long-term climate modeling.

Analyzing Quadratic Unconstrained Binary Optimization Problems Via Multicommodity Flows

PubMed Central

Wang, Di; Kleinberg, Robert D.

2009-01-01

Quadratic Unconstrained Binary Optimization (QUBO) problems concern the minimization of quadratic polynomials in n {0, 1}-valued variables. These problems are NP-complete, but prior work has identified a sequence of polynomial-time computable lower bounds on the minimum value, denoted by C2, C3, C4,…. It is known that C2 can be computed by solving a maximum-flow problem, whereas the only previously known algorithms for computing Ck (k > 2) require solving a linear program. In this paper we prove that C3 can be computed by solving a maximum multicommodity flow problem in a graph constructed from the quadratic function. In addition to providing a lower bound on the minimum value of the quadratic function on {0, 1}n, this multicommodity flow problem also provides some information about the coordinates of the point where this minimum is achieved. By looking at the edges that are never saturated in any maximum multicommodity flow, we can identify relational persistencies: pairs of variables that must have the same or different values in any minimizing assignment. We furthermore show that all of these persistencies can be detected by solving single-commodity flow problems in the same network. PMID:20161596

Analyzing Quadratic Unconstrained Binary Optimization Problems Via Multicommodity Flows.

PubMed

Wang, Di; Kleinberg, Robert D

2009-11-28

Quadratic Unconstrained Binary Optimization (QUBO) problems concern the minimization of quadratic polynomials in n {0, 1}-valued variables. These problems are NP-complete, but prior work has identified a sequence of polynomial-time computable lower bounds on the minimum value, denoted by C(2), C(3), C(4),…. It is known that C(2) can be computed by solving a maximum-flow problem, whereas the only previously known algorithms for computing C(k) (k > 2) require solving a linear program. In this paper we prove that C(3) can be computed by solving a maximum multicommodity flow problem in a graph constructed from the quadratic function. In addition to providing a lower bound on the minimum value of the quadratic function on {0, 1}(n), this multicommodity flow problem also provides some information about the coordinates of the point where this minimum is achieved. By looking at the edges that are never saturated in any maximum multicommodity flow, we can identify relational persistencies: pairs of variables that must have the same or different values in any minimizing assignment. We furthermore show that all of these persistencies can be detected by solving single-commodity flow problems in the same network.

The generalized quadratic knapsack problem. A neuronal network approach.

PubMed

Talaván, Pedro M; Yáñez, Javier

2006-05-01

The solution of an optimization problem through the continuous Hopfield network (CHN) is based on some energy or Lyapunov function, which decreases as the system evolves until a local minimum value is attained. A new energy function is proposed in this paper so that any 0-1 linear constrains programming with quadratic objective function can be solved. This problem, denoted as the generalized quadratic knapsack problem (GQKP), includes as particular cases well-known problems such as the traveling salesman problem (TSP) and the quadratic assignment problem (QAP). This new energy function generalizes those proposed by other authors. Through this energy function, any GQKP can be solved with an appropriate parameter setting procedure, which is detailed in this paper. As a particular case, and in order to test this generalized energy function, some computational experiments solving the traveling salesman problem are also included.

Bioaccumulation of CeO2 Nanoparticles by Earthworms in Biochar-Amended Soil: A Synchrotron Microspectroscopy Study.

PubMed

Servin, Alia D; Castillo-Michel, Hiram; Hernandez-Viezcas, Jose A; De Nolf, Wout; De La Torre-Roche, Roberto; Pagano, Luca; Pignatello, Joseph; Uchimiya, Minori; Gardea-Torresdey, Jorge; White, Jason C

2018-01-11

The interactions of nanoparticles (NPs) with biochar and soil components may substantially influence NP availability and toxicity to biota. In the present study, earthworms (Eisenia fetida) were exposed for 28 days to a residential or agricultural soil amended with 0-2000 mg of CeO 2 NP/kg and with biochar (produced by the pyrolysis of pecan shells at 350 and 600 °C) at various application rates [0-5% (w/w)]. After 28 days, earthworms were depurated and analyzed for Ce content, moisture content, and lipid peroxidation. The results showed minimal toxicity to the worms; however, biochar (350 or 600 °C) was the dominant factor, accounting for 94 and 84% of the variance for the moisture content and lipid peroxidation, respectively, in the exposed earthworms. For both soils with 1000 mg of CeO 2 /kg at 600 °C, biochar significantly decreased the accumulation of Ce in the worm tissues. Amendment with 350 °C biochar had mixed responses on Ce uptake. Analysis by micro X-ray fluorescence (μ-XRF) and micro X-ray absorption near edge structure (μ-XANES) was used to evaluate Ce localization, speciation, and persistence in CeO 2 - and biochar-exposed earthworms after depuration for 12, 48, and 72 h. Earthworms from the 500 mg of CeO 2 /kg and 0% biochar treatments eliminated most Ce after a 48 h depuration period. However, in the same treatment and with 5% BC-600 (biochar pyrolysis temperature of 600 °C), ingested biochar fragments (∼50 μm) with Ce adsorbed to the surfaces were retained in the gut after 72 h. Additionally, Ce remained in earthworms from the 2000 mg of CeO 2 /kg and 5% biochar treatments after depuration for 48 h. Analysis by μ-XANES showed that, within the earthworm tissues, Ce remained predominantly as Ce 4+ O 2 , with only few regions (2-3 μm 2 ) where it was found in the reduced form (Ce 3+ ). The present findings highlight that soil and biochar properties have a significant influence in the internalization of CeO 2 NPs in earthworms; such

CEOS Theory: A Comprehensive Approach to Understanding Hard to Maintain Behaviour Change.

PubMed

Borland, Ron

2017-03-01

This paper provides a brief introduction to CEOS theory, a comprehensive theory for understanding hard to maintain behaviour change. The name CEOS is an acronym for Context, Executive, and Operational Systems theory. Behaviour is theorised to be the result of the moment by moment interaction between internal needs (operational processes) in relation to environmental conditions, and for humans this is augmented by goal-directed, executive action which can transcend immediate contingencies. All behaviour is generated by operational processes. Goal-directed behaviours only triumph over contingency-generated competing behaviours when operational processes have been sufficiently activated to support them. Affective force can be generated around executive system (ES) goals from such things as memories of direct experience, vicarious experience, and emotionally charged communications mediated through stories the person generates. This paper makes some refinements and elaborations of the theory, particularly around the role of feelings, and of the importance of stories and scripts for facilitating executive action. It also sketches out how it reconceptualises a range of issues relevant to behaviour change. CEOS provides a framework for understanding the limitations of both informational and environmental approaches to behaviour change, the need for self-regulatory strategies and for taking into account more basic aspects of human functioning. © 2016 The Authors. Applied Psychology: Health and Well-Being published by John Wiley & Sons Ltd on behalf of International Association of Applied Psychology.

Exploring Quadratic Functions with Logger "Pro"

ERIC Educational Resources Information Center

Pope, Derek

2018-01-01

The author shares the lesson that he used to introduce the quadratic unit to students in an extended second-year algebra class, demonstrate why it was appropriate for his struggling learners, and discuss possible future modifications to this lesson.

Geometrical Solutions of Some Quadratic Equations with Non-Real Roots

ERIC Educational Resources Information Center

Pathak, H. K.; Grewal, A. S.

2002-01-01

This note gives geometrical/graphical methods of finding solutions of the quadratic equation ax[squared] + bx + c = 0, a [not equal to] 0, with non-real roots. Three different cases which give rise to non-real roots of the quadratic equation have been discussed. In case I a geometrical construction and its proof for finding the solutions of the…

Geometrical and Graphical Solutions of Quadratic Equations.

ERIC Educational Resources Information Center

Hornsby, E. John, Jr.

1990-01-01

Presented are several geometrical and graphical methods of solving quadratic equations. Discussed are Greek origins, Carlyle's method, von Staudt's method, fixed graph methods and imaginary solutions. (CW)

Monogamy inequality for distributed gaussian entanglement.

PubMed

Hiroshima, Tohya; Adesso, Gerardo; Illuminati, Fabrizio

2007-02-02

We show that for all n-mode Gaussian states of continuous variable systems, the entanglement shared among n parties exhibits the fundamental monogamy property. The monogamy inequality is proven by introducing the Gaussian tangle, an entanglement monotone under Gaussian local operations and classical communication, which is defined in terms of the squared negativity in complete analogy with the case of n-qubit systems. Our results elucidate the structure of quantum correlations in many-body harmonic lattice systems.

Influence of two types of organic matter on interaction of CeO2 nanoparticles with plants in hydroponic culture.

PubMed

Schwabe, Franziska; Schulin, Rainer; Limbach, Ludwig K; Stark, Wendelin; Bürge, Diane; Nowack, Bernd

2013-04-01

An important aspect in risk assessment of nanoparticles (NPs) is to understand their environmental interactions. We used hydroponic plant cultures to study nanoparticle-plant-root interaction and translocation and exposed wheat and pumpkin to suspensions of uncoated CeO2-NP for 8d (primary particle size 17-100 nm, 100 mg L(-1)) in the absence and presence of fulvic acid (FA) and gum arabic (GA) as representatives of different types of natural organic matter. The behavior of CeO2-NPs in the hydroponic solution was monitored regarding agglomeration, sedimentation, particle size distribution, surface charge, amounts of root association, and translocation into shoots. NP-dispersions were stable over 8d in the presence of FA or GA, but with growing plants, changes in pH, particle agglomeration rate, and hydrodynamic diameter were observed. None of the plants exhibited reduced growth or any toxic response during the experiment. We found that CeO2-NPs translocated into pumpkin shoots, whereas this did not occur in wheat plants. The presence of FA and GA affected the amount of CeO2 associated with roots (pure>FA>GA) but did not affect the translocation factor. Additionally, we could confirm via TEM and SEM that CeO2-NPs adhered strongly to root surfaces of both plant species. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mg Doping Induced Effects on Structural, Optical, and Electrical Properties as Well as Cytotoxicity of CeO2 Nanostructures

NASA Astrophysics Data System (ADS)

Iqbal, Javed; Jan, Tariq; Awan, M. S.; Naqvi, Sajjad Haider; Badshah, Noor; ullah, Asmat; Abbas, Fazzal

2016-04-01

Here, Mg x Ce1- x O2 (where x = 0, 0.01, 0.02, 0.03, 0.04, and 0.05) nanostructures have been successfully synthesized by using a simple, easy, and cost-effective soft chemical method. X-ray diffraction (XRD) patterns substantiate the single-phase formation of a CeO2 cubic fluorite structure for all samples. Infrared spectroscopy results depict the presence of peaks only related to Ce-O bonding, which confirms the XRD results. It has been observed via ultraviolet (UV)-visible spectroscopy that Mg doping has tuned the optical band gap of CeO2 significantly. The electrical conductivity of CeO2 nanostructures has been found to increase with Mg doping, which is attributed to enhancement in carrier concentration due to the different valance states of dopant and host ions. Selective cytotoxic behavior of Mg x Ce1- x O2 nanostructures has been determined for neuroblastoma (SH-SY5Y) cancerous and HEK-293 healthy cells. Both doped and undoped CeO2 nanostructures have been found to be toxic for cancer cells and safe toward healthy cells. This selective toxic behavior of the synthesized nanostructures has been assigned to the different levels of reactive oxygen species (ROS) generation in different types of cells. This makes the synthesized nanostructures a potential option for cancer therapy in the near future.

CeO2 nanocubes-graphene oxide as durable and highly active catalyst support for proton exchange membrane fuel cell

PubMed Central

Lei, M.; Wang, Z. B.; Li, J. S.; Tang, H. L.; Liu, W. J.; Wang, Y. G.

2014-01-01

Rapid degradation of cell performance still remains a significant challenge for proton exchange membrane fuel cell (PEMFC). In this work, we develop novel CeO2 nanocubes-graphene oxide nanocomposites as durable and highly active catalyst support for proton exchange membrane fuel cell. We show that the use of CeO2 as the radical scavenger in the catalysts remarkably improves the durability of the catalyst. The catalytic activity retention of Pt-graphene oxide-8 wt.% CeO2 nanocomposites reaches as high as 69% after 5000 CV-cycles at a high voltage range of 0.8–1.23 V, in contrast to 19% for that of the Pt-graphene oxide composites. The excellent durability of the Pt-CeO2 nanocubes-graphene oxide catalyst is attributed to the free radical scavenging activity of CeO2, which significantly slows down the chemical degradation of Nafion binder in catalytic layers, and then alleviates the decay of Pt catalysts, resulting in the excellent cycle life of Pt-CeO2-graphene oxide nanocomposite catalysts. Additionally, the performance of single cell assembled with Nafion 211 membrane and Pt-CeO2-graphene oxide catalysts with different CeO2 contents in the cathode as well as the Pt-C catalysts in the anode are also recorded and discussed in this study. PMID:25491655

CeO2 nanocubes-graphene oxide as durable and highly active catalyst support for proton exchange membrane fuel cell.

PubMed

Lei, M; Wang, Z B; Li, J S; Tang, H L; Liu, W J; Wang, Y G

2014-12-10

Rapid degradation of cell performance still remains a significant challenge for proton exchange membrane fuel cell (PEMFC). In this work, we develop novel CeO2 nanocubes-graphene oxide nanocomposites as durable and highly active catalyst support for proton exchange membrane fuel cell. We show that the use of CeO2 as the radical scavenger in the catalysts remarkably improves the durability of the catalyst. The catalytic activity retention of Pt-graphene oxide-8 wt.% CeO2 nanocomposites reaches as high as 69% after 5000 CV-cycles at a high voltage range of 0.8-1.23 V, in contrast to 19% for that of the Pt-graphene oxide composites. The excellent durability of the Pt-CeO2 nanocubes-graphene oxide catalyst is attributed to the free radical scavenging activity of CeO2, which significantly slows down the chemical degradation of Nafion binder in catalytic layers, and then alleviates the decay of Pt catalysts, resulting in the excellent cycle life of Pt-CeO2-graphene oxide nanocomposite catalysts. Additionally, the performance of single cell assembled with Nafion 211 membrane and Pt-CeO2-graphene oxide catalysts with different CeO2 contents in the cathode as well as the Pt-C catalysts in the anode are also recorded and discussed in this study.

CeO2 nanocubes-graphene oxide as durable and highly active catalyst support for proton exchange membrane fuel cell

NASA Astrophysics Data System (ADS)

Lei, M.; Wang, Z. B.; Li, J. S.; Tang, H. L.; Liu, W. J.; Wang, Y. G.

2014-12-01

Rapid degradation of cell performance still remains a significant challenge for proton exchange membrane fuel cell (PEMFC). In this work, we develop novel CeO2 nanocubes-graphene oxide nanocomposites as durable and highly active catalyst support for proton exchange membrane fuel cell. We show that the use of CeO2 as the radical scavenger in the catalysts remarkably improves the durability of the catalyst. The catalytic activity retention of Pt-graphene oxide-8 wt.% CeO2 nanocomposites reaches as high as 69% after 5000 CV-cycles at a high voltage range of 0.8-1.23 V, in contrast to 19% for that of the Pt-graphene oxide composites. The excellent durability of the Pt-CeO2 nanocubes-graphene oxide catalyst is attributed to the free radical scavenging activity of CeO2, which significantly slows down the chemical degradation of Nafion binder in catalytic layers, and then alleviates the decay of Pt catalysts, resulting in the excellent cycle life of Pt-CeO2-graphene oxide nanocomposite catalysts. Additionally, the performance of single cell assembled with Nafion 211 membrane and Pt-CeO2-graphene oxide catalysts with different CeO2 contents in the cathode as well as the Pt-C catalysts in the anode are also recorded and discussed in this study.

CEOs, Information, and Decision Making: Scanning the Environment for Strategic Advantage.

ERIC Educational Resources Information Center

Auster, Ethel; Choo, Chun Wei

1994-01-01

Describes a study that investigated how CEOs (Chief Executive Officers) in the Canadian publishing and telecommunications industries acquire and use information about the business environment. Topics discussed include environmental scanning; perceived environmental uncertainty; information sources; information use in decision making; and a…

Ultrafine Nanocrystalline CeO2@C-Containing NaAlH4 with Fast Kinetics and Good Reversibility for Hydrogen Storage.

PubMed

Zhang, Xin; Liu, Yongfeng; Wang, Ke; Li, You; Gao, Mingxia; Pan, Hongge

2015-12-21

A nanocrystalline CeO2@C-containing NaAlH4 composite is successfully synthesized in situ by hydrogenating a NaH-Al mixture doped with CeO2@C. Compared with NaAlH4 , the as-prepared CeO2@C-containing NaAlH4 composite, with a minor amount of excess Al, exhibits significantly improved hydrogen storage properties. The dehydrogenation onset temperature of the hydrogenated [NaH-Al-7 wt % CeO2@C]-0.04Al sample is 77 °C lower than that of the pristine sample because of a reduced kinetic barrier. More importantly, the dehydrogenated sample absorbs ∼4.7 wt % hydrogen within 35 min at 100°C and 10 MPa of hydrogen. Compositional and structural analyses reveal that CeO2 is converted to CeH2 during ball milling and that the newly formed CeH2 works with the excess of Al to synergistically improve the hydrogen storage properties of NaAlH4. Our findings will aid in the rational design of novel catalyst-doped complex hydride systems with low operating temperatures, fast kinetics, and long-term cyclability. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Entropy generation in Gaussian quantum transformations: applying the replica method to continuous-variable quantum information theory

NASA Astrophysics Data System (ADS)

Gagatsos, Christos N.; Karanikas, Alexandros I.; Kordas, Georgios; Cerf, Nicolas J.

2016-02-01

In spite of their simple description in terms of rotations or symplectic transformations in phase space, quadratic Hamiltonians such as those modelling the most common Gaussian operations on bosonic modes remain poorly understood in terms of entropy production. For instance, determining the quantum entropy generated by a Bogoliubov transformation is notably a hard problem, with generally no known analytical solution, while it is vital to the characterisation of quantum communication via bosonic channels. Here we overcome this difficulty by adapting the replica method, a tool borrowed from statistical physics and quantum field theory. We exhibit a first application of this method to continuous-variable quantum information theory, where it enables accessing entropies in an optical parametric amplifier. As an illustration, we determine the entropy generated by amplifying a binary superposition of the vacuum and a Fock state, which yields a surprisingly simple, yet unknown analytical expression.

Quadratic spatial soliton interactions

NASA Astrophysics Data System (ADS)

Jankovic, Ladislav

Quadratic spatial soliton interactions were investigated in this Dissertation. The first part deals with characterizing the principal features of multi-soliton generation and soliton self-reflection. The second deals with two beam processes leading to soliton interactions and collisions. These subjects were investigated both theoretically and experimentally. The experiments were performed by using potassium niobate (KNBO 3) and periodically poled potassium titanyl phosphate (KTP) crystals. These particular crystals were desirable for these experiments because of their large nonlinear coefficients and, more importantly, because the experiments could be performed under non-critical-phase-matching (NCPM) conditions. The single soliton generation measurements, performed on KNBO3 by launching the fundamental component only, showed a broad angular acceptance bandwidth which was important for the soliton collisions performed later. Furthermore, at high input intensities multi-soliton generation was observed for the first time. The influence on the multi-soliton patterns generated of the input intensity and beam symmetry was investigated. The combined experimental and theoretical efforts indicated that spatial and temporal noise on the input laser beam induced multi-soliton patterns. Another research direction pursued was intensity dependent soliton routing by using of a specially engineered quadratically nonlinear interface within a periodically poled KTP sample. This was the first time demonstration of the self-reflection phenomenon in a system with a quadratic nonlinearity. The feature investigated is believed to have a great potential for soliton routing and manipulation by engineered structures. A detailed investigation was conducted on two soliton interaction and collision processes. Birth of an additional soliton resulting from a two soliton collision was observed and characterized for the special case of a non-planar geometry. A small amount of spiraling, up to 30

Ce3+-ion, Surface Oxygen Vacancy, and Visible Light-induced Photocatalytic Dye Degradation and Photocapacitive Performance of CeO2-Graphene Nanostructures.

PubMed

Khan, Mohammad Ehtisham; Khan, Mohammad Mansoob; Cho, Moo Hwan

2017-07-19

Cerium oxide nanoparticles (CeO 2 NPs) were fabricated and grown on graphene sheets using a facile, low cost hydrothermal approach and subsequently characterized using different standard characterization techniques. X-ray photoelectron spectroscopy and electron paramagnetic resonance revealed the changes in surface states, composition, changes in Ce 4+ to Ce 3+ ratio, and other defects. Transmission electron microscopy (TEM) and high resolution TEM revealed that the fabricated CeO 2 NPs to be spherical with particle size of ~10-12 nm. Combination of defects in CeO 2 NPs with optimal amount of two-dimensional graphene sheets had a significant effect on the properties of the resulting hybrid CeO 2 -Graphene nanostructures, such as improved optical, photocatalytic, and photocapacitive performance. The excellent photocatalytic degradation performances were examined by monitoring their ability to degrade Congo red ~94.5% and methylene blue dye ~98% under visible light irradiation. The photoelectrode performance had a maximum photocapacitance of 177.54 Fg -1 and exhibited regular capacitive behavior. Therefore, the Ce 3+ -ion, surface-oxygen-vacancies, and defects-induced behavior can be attributed to the suppression of the recombination of photo-generated electron-hole pairs due to the rapid charge transfer between the CeO 2 NPs and graphene sheets. These findings will have a profound effect on the use of CeO 2 -Graphene nanostructures for future energy and environment-related applications.

"The role of facial appearance on CEO selection after firm misconduct:" Correction to Gomulya et al. (2016).

PubMed

2017-04-01

Reports an error in "The Role of Facial Appearance on CEO Selection After Firm Misconduct" by David Gomulya, Elaine M. Wong, Margaret E. Ormiston and Warren Boeker ( Journal of Applied Psychology , Advanced Online Publication, Dec 19, 2016, np). The wrong figure files were used. All versions of this article have been corrected. (The following abstract of the original article appeared in record 2016-60831-001.) We investigate a particular aspect of CEO successor trustworthiness that may be critically important after a firm has engaged in financial misconduct. Specifically, drawing on prior research that suggests that facial appearance is one critical way in which trustworthiness is signaled, we argue that leaders who convey integrity, a component of trustworthiness, will be more likely to be selected as successors after financial restatement. We predict that such appointments garner more positive reactions by external observers such as investment analysts and the media because these CEOs are perceived as having greater integrity. In an archival study of firms that have announced financial restatements, we find support for our predictions. These findings have implications for research on CEO succession, leadership selection, facial appearance, and firm misconduct. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

High thermal stability of La 2O 3 and CeO 2-stabilized tetragonal ZrO 2

DOE PAGES

Wang, Shichao; Xie, Hong; Lin, Yuyuan; ...

2016-02-15

Catalyst support materials of tetragonal ZrO 2, stabilized by either La 2O 3 (La 2O 3-ZrO 2) or CeO 2 (CeO 2-ZrO 2), were synthesized under hydrothermal conditions at 200 °C with NH 4OH or tetramethylammonium hydroxide as the mineralizer. From In Situ synchrotron powder X-ray diffraction and small-angle X-ray scattering measurements, the calcined La 2O 3-ZrO 2 and CeO 2-ZrO 2 supports were nonporous nanocrystallites that exhibited rectangular shapes with thermal stability up to 1000 °C in air. These supports had an average size of ~10 nm and a surface area of 59-97 m 2/g. The catalysts Pt/La 2Omore » 3-ZrO 2 and Pt/CeO 2-ZrO 2 were prepared by using atomic layer deposition with varying Pt loadings from 6.3-12.4 wt %. Mono-dispersed Pt nanoparticles of ~3 nm were obtained for these catalysts. As a result, the incorporation of La 2O 3 and CeO 2 into the t-ZrO 2 structure did not affect the nature of the active sites for the Pt/ZrO 2 catalysts for the water-gas-shift (WGS) reaction.« less

Non-gaussianity versus nonlinearity of cosmological perturbations.

PubMed

Verde, L

2001-06-01

Following the discovery of the cosmic microwave background, the hot big-bang model has become the standard cosmological model. In this theory, small primordial fluctuations are subsequently amplified by gravity to form the large-scale structure seen today. Different theories for unified models of particle physics, lead to different predictions for the statistical properties of the primordial fluctuations, that can be divided in two classes: gaussian and non-gaussian. Convincing evidence against or for gaussian initial conditions would rule out many scenarios and point us toward a physical theory for the origin of structures. The statistical distribution of cosmological perturbations, as we observe them, can deviate from the gaussian distribution in several different ways. Even if perturbations start off gaussian, nonlinear gravitational evolution can introduce non-gaussian features. Additionally, our knowledge of the Universe comes principally from the study of luminous material such as galaxies, but galaxies might not be faithful tracers of the underlying mass distribution. The relationship between fluctuations in the mass and in the galaxies distribution (bias), is often assumed to be local, but could well be nonlinear. Moreover, galaxy catalogues use the redshift as third spatial coordinate: the resulting redshift-space map of the galaxy distribution is nonlinearly distorted by peculiar velocities. Nonlinear gravitational evolution, biasing, and redshift-space distortion introduce non-gaussianity, even in an initially gaussian fluctuation field. I investigate the statistical tools that allow us, in principle, to disentangle the above different effects, and the observational datasets we require to do so in practice.

Galaxy bias and primordial non-Gaussianity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Assassi, Valentin; Baumann, Daniel; Schmidt, Fabian, E-mail: assassi@ias.edu, E-mail: D.D.Baumann@uva.nl, E-mail: fabians@MPA-Garching.MPG.DE

2015-12-01

We present a systematic study of galaxy biasing in the presence of primordial non-Gaussianity. For a large class of non-Gaussian initial conditions, we define a general bias expansion and prove that it is closed under renormalization, thereby showing that the basis of operators in the expansion is complete. We then study the effects of primordial non-Gaussianity on the statistics of galaxies. We show that the equivalence principle enforces a relation between the scale-dependent bias in the galaxy power spectrum and that in the dipolar part of the bispectrum. This provides a powerful consistency check to confirm the primordial origin ofmore » any observed scale-dependent bias. Finally, we also discuss the imprints of anisotropic non-Gaussianity as motivated by recent studies of higher-spin fields during inflation.« less

Effect of Nano CeO2 Addition on the Microstructure and Properties of a Cu-Al-Ni Shape Memory Alloy

NASA Astrophysics Data System (ADS)

Pandey, Abhishek; Jain, Ashish Kumar; Hussain, Shahadat; Sampath, V.; Dasgupta, Rupa

2016-08-01

This article deals with the effect of adding nano CeO2 to act as a grain pinner/refiner to a known Cu-Al-Ni shape memory alloy. Elements were taken in a predefined ratio to prepare 300 g alloy per batch and melted in an induction furnace. Casting was followed by homogenization at 1173 K (900 °C) and rolling to make sheets of 0.5-mm thickness. Further, samples were characterized for microstructure using optical and electron microscope, hardness, and different phase studies by X-ray and transformation temperatures by differential scanning calorimetry. X-ray peak broadenings and changes were investigated to estimate the crystallite size, lattice strain, and phase changes due to different processing steps. A nearly uniform distribution of CeO2 and better martensitic structure were observed with increasing CeO2. The addition of CeO2 also shows a visible effect on the transformation temperature and phase formation.

Second order Pseudo-gaussian shaper

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beche, Jean-Francois

2002-11-22

The purpose of this document is to provide a calculus spreadsheet for the design of second-order pseudo-gaussian shapers. A very interesting reference is given by C.H. Mosher ''Pseudo-Gaussian Transfer Functions with Superlative Recovery'', IEEE TNS Volume 23, p. 226-228 (1976). Fred Goulding and Don Landis have studied the structure of those filters and their implementation and this document will outline the calculation leading to the relation between the coefficients of the filter. The general equation of the second order pseudo-gaussian filter is: f(t) = P{sub 0} {center_dot} e{sup -3kt} {center_dot} sin{sup 2}(kt). The parameter k is a normalization factor.

Ethanol Sensor of CdO/Al2O3/CeO2 Obtained from Ce-DOPED Layered Double Hydroxides with High Response and Selectivity

NASA Astrophysics Data System (ADS)

Xu, Dongmei; Guan, Meiyu; Xu, Qinghong; Guo, Ying; Wang, Yao

2013-04-01

In this paper, Ce-doped CdAl layered double hydroxide (LDH) was first synthesized and the derivative CdO/Al2O3/CeO2 composite oxide was prepared by calcining Ce-doped CdAl LDH. The structure, morphology and chemical state of the Ce doped CdAl LDH and CdO/Al2O3/CeO2 were also investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), solid state nuclear magnetic resonance (SSNMR), scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The gas sensing properties of CdO/Al2O3/CeO2 to ethanol were further studied and compared with CdO/Al2O3 prepared from CdAl LDH, CeO2 powder as well as the calcined Ce salt. It turns out that CdO/Al2O3/CeO2 sensor shows best performance in ethanol response. Besides, CdO/Al2O3/CeO2 possesses short response/recovery time (12/72 s) as well as remarkable selectivity in ethanol sensing, which means composite oxides prepared from LDH are very promising in gas sensing application.

CEOS Ocean Variables Enabling Research and Applications for Geo (COVERAGE)

NASA Astrophysics Data System (ADS)

Tsontos, V. M.; Vazquez, J.; Zlotnicki, V.

2017-12-01

The CEOS Ocean Variables Enabling Research and Applications for GEO (COVERAGE) initiative seeks to facilitate joint utilization of different satellite data streams on ocean physics, better integrated with biological and in situ observations, including near real-time data streams in support of oceanographic and decision support applications for societal benefit. COVERAGE aligns with programmatic objectives of CEOS (the Committee on Earth Observation Satellites) and the missions of GEO-MBON (Marine Biodiversity Observation Network) and GEO-Blue Planet, which are to advance and exploit synergies among the many observational programs devoted to ocean and coastal waters. COVERAGE is conceived of as 3 year pilot project involving international collaboration. It focuses on implementing technologies, including cloud based solutions, to provide a data rich, web-based platform for integrated ocean data delivery and access: multi-parameter observations, easily discoverable and usable, organized by disciplines, available in near real-time, collocated to a common grid and including climatologies. These will be complemented by a set of value-added data services available via the COVERAGE portal including an advanced Web-based visualization interface, subsetting/extraction, data collocation/matchup and other relevant on demand processing capabilities. COVERAGE development will be organized around priority use cases and applications identified by GEO and agency partners. The initial phase will be to develop co-located 25km products from the four Ocean Virtual Constellations (VCs), Sea Surface Temperature, Sea Level, Ocean Color, and Sea Surface Winds. This aims to stimulate work among the ocean VCs while developing products and system functionality based on community recommendations. Such products as anomalies from a time mean, would build on the theme of applications with a relevance to CEOS/GEO mission and vision. Here we provide an overview of the COVERAGE initiative with an

Initial Reduction of CO2 on Pd-, Ru-, and Cu-Doped CeO2(111) Surfaces: Effects of Surface Modification on Catalytic Activity and Selectivity.

PubMed

Guo, Chen; Wei, Shuxian; Zhou, Sainan; Zhang, Tian; Wang, Zhaojie; Ng, Siu-Pang; Lu, Xiaoqing; Wu, Chi-Man Lawrence; Guo, Wenyue

2017-08-09

Surface modification by metal doping is an effective treatment technique for improving surface properties for CO 2 reduction. Herein, the effects of doped Pd, Ru, and Cu on the adsorption, activation, and reduction selectivity of CO 2 on CeO 2 (111) were investigated by periodic density functional theory. The doped metals distorted the configuration of a perfect CeO 2 (111) by weakening the adjacent Ce-O bond strength, and Pd doping was beneficial for generating a highly active O vacancy. The analyses of adsorption energy, charge density difference, and density of states confirmed that the doped metals were conducive for enhancing CO 2 adsorption, especially for Cu/CeO 2 (111). The initial reductive dissociation CO 2 → CO* + O* on metal-doped CeO 2 (111) followed the sequence of Cu- > perfect > Pd- > Ru-doped CeO 2 (111); the reductive hydrogenation CO 2 + H → COOH* followed the sequence of Cu- > perfect > Ru- > Pd-doped CeO 2 (111), in which the most competitive route on Cu/CeO 2 (111) was exothermic by 0.52 eV with an energy barrier of 0.16 eV; the reductive hydrogenation CO 2 + H → HCOO* followed the sequence of Ru- > perfect > Pd-doped CeO 2 (111). Energy barrier decomposition analyses were performed to identify the governing factors of bond activation and scission along the initial CO 2 reduction routes. Results of this study provided deep insights into the effect of surface modification on the initial reduction mechanisms of CO 2 on metal-doped CeO 2 (111) surfaces.

OPTOELECTRONICS, FIBER OPTICS, AND OTHER ASPECTS OF QUANTUM ELECTRONICS: Influence of the Rayleigh backscattering on the mode composition of radiation in multimode graded-index waveguides with a quadratic refractive-index profile

NASA Astrophysics Data System (ADS)

Esayan, G. L.; Krivoshlykov, S. G.

1989-08-01

A method of coherent states is used to describe the process of Rayleigh scattering in a multimode graded-index waveguide with a quadratic refractive-index profile. Explicit expressions are obtained for the coefficients representing excitation of Gaussian-Hermite backscattering modes in two cases of practical importance: excitation of a waveguide by an extended noncoherent light source and selective excitation of different modes at the entry to a waveguide. An analysis is also made of the coefficients of coupling between forward and backward modes. Explicit expressions for the coefficients representing capture of backscattered radiation by a waveguide are obtained for two special cases of excitation (extended light source and zeroth mode).

Finite Element Simulation of Articular Contact Mechanics with Quadratic Tetrahedral Elements

PubMed Central

Maas, Steve A.; Ellis, Benjamin J.; Rawlins, David S.; Weiss, Jeffrey A.

2016-01-01

Although it is easier to generate finite element discretizations with tetrahedral elements, trilinear hexahedral (HEX8) elements are more often used in simulations of articular contact mechanics. This is due to numerical shortcomings of linear tetrahedral (TET4) elements, limited availability of quadratic tetrahedron elements in combination with effective contact algorithms, and the perceived increased computational expense of quadratic finite elements. In this study we implemented both ten-node (TET10) and fifteen-node (TET15) quadratic tetrahedral elements in FEBio (www.febio.org) and compared their accuracy, robustness in terms of convergence behavior and computational cost for simulations relevant to articular contact mechanics. Suitable volume integration and surface integration rules were determined by comparing the results of several benchmark contact problems. The results demonstrated that the surface integration rule used to evaluate the contact integrals for quadratic elements affected both convergence behavior and accuracy of predicted stresses. The computational expense and robustness of both quadratic tetrahedral formulations compared favorably to the HEX8 models. Of note, the TET15 element demonstrated superior convergence behavior and lower computational cost than both the TET10 and HEX8 elements for meshes with similar numbers of degrees of freedom in the contact problems that we examined. Finally, the excellent accuracy and relative efficiency of these quadratic tetrahedral elements was illustrated by comparing their predictions with those for a HEX8 mesh for simulation of articular contact in a fully validated model of the hip. These results demonstrate that TET10 and TET15 elements provide viable alternatives to HEX8 elements for simulation of articular contact mechanics. PMID:26900037

Finite element simulation of articular contact mechanics with quadratic tetrahedral elements.

PubMed

Maas, Steve A; Ellis, Benjamin J; Rawlins, David S; Weiss, Jeffrey A

2016-03-21

Although it is easier to generate finite element discretizations with tetrahedral elements, trilinear hexahedral (HEX8) elements are more often used in simulations of articular contact mechanics. This is due to numerical shortcomings of linear tetrahedral (TET4) elements, limited availability of quadratic tetrahedron elements in combination with effective contact algorithms, and the perceived increased computational expense of quadratic finite elements. In this study we implemented both ten-node (TET10) and fifteen-node (TET15) quadratic tetrahedral elements in FEBio (www.febio.org) and compared their accuracy, robustness in terms of convergence behavior and computational cost for simulations relevant to articular contact mechanics. Suitable volume integration and surface integration rules were determined by comparing the results of several benchmark contact problems. The results demonstrated that the surface integration rule used to evaluate the contact integrals for quadratic elements affected both convergence behavior and accuracy of predicted stresses. The computational expense and robustness of both quadratic tetrahedral formulations compared favorably to the HEX8 models. Of note, the TET15 element demonstrated superior convergence behavior and lower computational cost than both the TET10 and HEX8 elements for meshes with similar numbers of degrees of freedom in the contact problems that we examined. Finally, the excellent accuracy and relative efficiency of these quadratic tetrahedral elements was illustrated by comparing their predictions with those for a HEX8 mesh for simulation of articular contact in a fully validated model of the hip. These results demonstrate that TET10 and TET15 elements provide viable alternatives to HEX8 elements for simulation of articular contact mechanics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Information geometry of Gaussian channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monras, Alex; CNR-INFM Coherentia, Napoli; CNISM Unita di Salerno

2010-06-15

We define a local Riemannian metric tensor in the manifold of Gaussian channels and the distance that it induces. We adopt an information-geometric approach and define a metric derived from the Bures-Fisher metric for quantum states. The resulting metric inherits several desirable properties from the Bures-Fisher metric and is operationally motivated by distinguishability considerations: It serves as an upper bound to the attainable quantum Fisher information for the channel parameters using Gaussian states, under generic constraints on the physically available resources. Our approach naturally includes the use of entangled Gaussian probe states. We prove that the metric enjoys some desirablemore » properties like stability and covariance. As a by-product, we also obtain some general results in Gaussian channel estimation that are the continuous-variable analogs of previously known results in finite dimensions. We prove that optimal probe states are always pure and bounded in the number of ancillary modes, even in the presence of constraints on the reduced state input in the channel. This has experimental and computational implications. It limits the complexity of optimal experimental setups for channel estimation and reduces the computational requirements for the evaluation of the metric: Indeed, we construct a converging algorithm for its computation. We provide explicit formulas for computing the multiparametric quantum Fisher information for dissipative channels probed with arbitrary Gaussian states and provide the optimal observables for the estimation of the channel parameters (e.g., bath couplings, squeezing, and temperature).« less

On Volterra quadratic stochastic operators with continual state space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ganikhodjaev, Nasir; Hamzah, Nur Zatul Akmar

2015-05-15

Let (X,F) be a measurable space, and S(X,F) be the set of all probability measures on (X,F) where X is a state space and F is σ - algebraon X. We consider a nonlinear transformation (quadratic stochastic operator) defined by (Vλ)(A) = ∫{sub X}∫{sub X}P(x,y,A)dλ(x)dλ(y), where P(x, y, A) is regarded as a function of two variables x and y with fixed A ∈ F . A quadratic stochastic operator V is called a regular, if for any initial measure the strong limit lim{sub n→∞} V{sup n }(λ) is exists. In this paper, we construct a family of quadratic stochastic operators defined on themore » segment X = [0,1] with Borel σ - algebra F on X , prove their regularity and show that the limit measure is a Dirac measure.« less

Schur Stability Regions for Complex Quadratic Polynomials

ERIC Educational Resources Information Center

Cheng, Sui Sun; Huang, Shao Yuan

2010-01-01

Given a quadratic polynomial with complex coefficients, necessary and sufficient conditions are found in terms of the coefficients such that all its roots have absolute values less than 1. (Contains 3 figures.)

Microarsecond models for the celestial motions of the CIP and CEO

NASA Astrophysics Data System (ADS)

Capitaine, N.

2004-09-01

The Celestial intermediate pole (CIP) and Celestial ephemeris (orintermediate) origin (CEO/CIO) have been adopted by the IAU (c.f. IAU2000 Resolution B1.8) as the celestial pole and origin, respectively,to be used for realizing the intermediate celestial system between theInternational Terrestrial System (ITRS) and Geocentric CelestialReference System (GCRS). Resolution B1.8 has also recommended that theInternational Earth Rotation and Reference Systems Service (IERS)continue to provide users with data and algorithms for the conventionaltransformation. The IAU 2000 Resolutions have been implemented in theIERS 2003 Conventions including Tables and routines that provide thecelestial motions of the CIP and the CEO with a theoretical accuracy ofone microarcsecond after one century using either the classical or thenew transformation. This paper reports on the method used for achievingthis accuracy in the positions of the CIP and CIO and on the differencebetween this rigorous procedure and the pre-2003 classical one.

Multivariate Bayesian analysis of Gaussian, right censored Gaussian, ordered categorical and binary traits using Gibbs sampling

PubMed Central

Korsgaard, Inge Riis; Lund, Mogens Sandø; Sorensen, Daniel; Gianola, Daniel; Madsen, Per; Jensen, Just

2003-01-01

A fully Bayesian analysis using Gibbs sampling and data augmentation in a multivariate model of Gaussian, right censored, and grouped Gaussian traits is described. The grouped Gaussian traits are either ordered categorical traits (with more than two categories) or binary traits, where the grouping is determined via thresholds on the underlying Gaussian scale, the liability scale. Allowances are made for unequal models, unknown covariance matrices and missing data. Having outlined the theory, strategies for implementation are reviewed. These include joint sampling of location parameters; efficient sampling from the fully conditional posterior distribution of augmented data, a multivariate truncated normal distribution; and sampling from the conditional inverse Wishart distribution, the fully conditional posterior distribution of the residual covariance matrix. Finally, a simulated dataset was analysed to illustrate the methodology. This paper concentrates on a model where residuals associated with liabilities of the binary traits are assumed to be independent. A Bayesian analysis using Gibbs sampling is outlined for the model where this assumption is relaxed. PMID:12633531

Elegant Gaussian beams for enhanced optical manipulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alpmann, Christina, E-mail: c.alpmann@uni-muenster.de; Schöler, Christoph; Denz, Cornelia

2015-06-15

Generation of micro- and nanostructured complex light beams attains increasing impact in photonics and laser applications. In this contribution, we demonstrate the implementation and experimental realization of the relatively unknown, but highly versatile class of complex-valued Elegant Hermite- and Laguerre-Gaussian beams. These beams create higher trapping forces compared to standard Gaussian light fields due to their propagation changing properties. We demonstrate optical trapping and alignment of complex functional particles as nanocontainers with standard and Elegant Gaussian light beams. Elegant Gaussian beams will inspire manifold applications in optical manipulation, direct laser writing, or microscopy, where the design of the point-spread functionmore » is relevant.« less

Big City Superintendent as Powerful CEO: Paul Vallas in Philadelphia

ERIC Educational Resources Information Center

Useem, Elizabeth

2009-01-01

This case study of the leadership of Paul Vallas as CEO of the Philadelphia city schools from 2002-2007 demonstrates that No Child Left Behind has enhanced the formal authority of big city district chiefs even though they are constrained by its accountability mandates and by the pressures from a growing number of influential stakeholder groups. In…

Orthogonal Gaussian process models

DOE PAGES

Plumlee, Matthew; Joseph, V. Roshan

2017-01-01

Gaussian processes models are widely adopted for nonparameteric/semi-parametric modeling. Identifiability issues occur when the mean model contains polynomials with unknown coefficients. Though resulting prediction is unaffected, this leads to poor estimation of the coefficients in the mean model, and thus the estimated mean model loses interpretability. This paper introduces a new Gaussian process model whose stochastic part is orthogonal to the mean part to address this issue. As a result, this paper also discusses applications to multi-fidelity simulations using data examples.

Orthogonal Gaussian process models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plumlee, Matthew; Joseph, V. Roshan

Gaussian processes models are widely adopted for nonparameteric/semi-parametric modeling. Identifiability issues occur when the mean model contains polynomials with unknown coefficients. Though resulting prediction is unaffected, this leads to poor estimation of the coefficients in the mean model, and thus the estimated mean model loses interpretability. This paper introduces a new Gaussian process model whose stochastic part is orthogonal to the mean part to address this issue. As a result, this paper also discusses applications to multi-fidelity simulations using data examples.

Linear and quadratic static response functions and structure functions in Yukawa liquids.

PubMed

Magyar, Péter; Donkó, Zoltán; Kalman, Gabor J; Golden, Kenneth I

2014-08-01

We compute linear and quadratic static density response functions of three-dimensional Yukawa liquids by applying an external perturbation potential in molecular dynamics simulations. The response functions are also obtained from the equilibrium fluctuations (static structure factors) in the system via the fluctuation-dissipation theorems. The good agreement of the quadratic response functions, obtained in the two different ways, confirms the quadratic fluctuation-dissipation theorem. We also find that the three-point structure function may be factorizable into two-point structure functions, leading to a cluster representation of the equilibrium triplet correlation function.

Issues in the digital implementation of control compensators. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Moroney, P.

1979-01-01

Techniques developed for the finite-precision implementation of digital filters were used, adapted, and extended for digital feedback compensators, with particular emphasis on steady state, linear-quadratic-Gaussian compensators. Topics covered include: (1) the linear-quadratic-Gaussian problem; (2) compensator structures; (3) architectural issues: serialism, parallelism, and pipelining; (4) finite wordlength effects: quantization noise, quantizing the coefficients, and limit cycles; and (5) the optimization of structures.

Distillation and purification of symmetric entangled Gaussian states

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fiurasek, Jaromir

2010-10-15

We propose an entanglement distillation and purification scheme for symmetric two-mode entangled Gaussian states that allows to asymptotically extract a pure entangled Gaussian state from any input entangled symmetric Gaussian state. The proposed scheme is a modified and extended version of the entanglement distillation protocol originally developed by Browne et al. [Phys. Rev. A 67, 062320 (2003)]. A key feature of the present protocol is that it utilizes a two-copy degaussification procedure that involves a Mach-Zehnder interferometer with single-mode non-Gaussian filters inserted in its two arms. The required non-Gaussian filtering operations can be implemented by coherently combining two sequences ofmore » single-photon addition and subtraction operations.« less

Improve electrochemical performance of CeO2 surface modification LiNi0.80Co0.15Al0.05O2 cathode material

NASA Astrophysics Data System (ADS)

Xia, Shubiao; Zhang, Yingjie; Dong, Peng; Zhang, Yannan

2014-06-01

Lithium ion battery cathode material LiNi0.8Co0.15Al0.05O2 cathode has successfully prepared by co-precipitation. CeO2 surface modification has improved LiNi0.80Co0.15Al0.05O2 electrochemical performance use sol-gel method and subsequent heat treatment at 600 °C for 5 h. Different to other conventional coating material, CeO2 coating layer can not only inhibit the reaction of the electrode and the electrolyte, but also can reduce the impedance of electron transfer due to its high conductivity, and inhibit the production of Ni2+ because of its high oxidation. The surface-modified and pristine LiNi0.80Co0.15Al0.05O2 powders are characterized by XRD, SEM, TEM, XPS, CV and DSC. When CeO2 coating is 0.02% (mole ratio), contrast to pristine NCA, the CeO2-coated NCA cathode exhibits no decrease in its initial specific capacity of 184 mAh g -1 (at 0.2 C) and excellent capacity retention (86% of its initial capacity at 1 C) between 2.75 and 4.3 V after 100 cycles. The results indicate that the CeO2 surface treatment should be an effective way to improve cycle properties due to CeO2 inhibit the electrodes and the electrolyte side effects.

Stochastic differential calculus for Gaussian and non-Gaussian noises: A critical review

NASA Astrophysics Data System (ADS)

Falsone, G.

2018-03-01

In this paper a review of the literature works devoted to the study of stochastic differential equations (SDEs) subjected to Gaussian and non-Gaussian white noises and to fractional Brownian noises is given. In these cases, particular attention must be paid in treating the SDEs because the classical rules of the differential calculus, as the Newton-Leibnitz one, cannot be applied or are applicable with many difficulties. Here all the principal approaches solving the SDEs are reported for any kind of noise, highlighting the negative and positive properties of each one and making the comparisons, where it is possible.

Propagation of elliptic-Gaussian beams in strongly nonlocal nonlinear media

NASA Astrophysics Data System (ADS)

Deng, Dongmei; Guo, Qi

2011-10-01

The propagation of the elliptic-Gaussian beams is studied in strongly nonlocal nonlinear media. The elliptic-Gaussian beams and elliptic-Gaussian vortex beams are obtained analytically and numerically. The patterns of the elegant Ince-Gaussian and the generalized Ince-Gaussian beams are varied periodically when the input power is equal to the critical power. The stability is verified by perturbing the initial beam by noise. By simulating the propagation of the elliptic-Gaussian beams in liquid crystal, we find that when the mode order is not big enough, there exists the quasi-elliptic-Gaussian soliton states.

The effect of noise and lipid signals on determination of Gaussian and non-Gaussian diffusion parameters in skeletal muscle.

PubMed

Cameron, Donnie; Bouhrara, Mustapha; Reiter, David A; Fishbein, Kenneth W; Choi, Seongjin; Bergeron, Christopher M; Ferrucci, Luigi; Spencer, Richard G

2017-07-01

This work characterizes the effect of lipid and noise signals on muscle diffusion parameter estimation in several conventional and non-Gaussian models, the ultimate objectives being to characterize popular fat suppression approaches for human muscle diffusion studies, to provide simulations to inform experimental work and to report normative non-Gaussian parameter values. The models investigated in this work were the Gaussian monoexponential and intravoxel incoherent motion (IVIM) models, and the non-Gaussian kurtosis and stretched exponential models. These were evaluated via simulations, and in vitro and in vivo experiments. Simulations were performed using literature input values, modeling fat contamination as an additive baseline to data, whereas phantom studies used a phantom containing aliphatic and olefinic fats and muscle-like gel. Human imaging was performed in the hamstring muscles of 10 volunteers. Diffusion-weighted imaging was applied with spectral attenuated inversion recovery (SPAIR), slice-select gradient reversal and water-specific excitation fat suppression, alone and in combination. Measurement bias (accuracy) and dispersion (precision) were evaluated, together with intra- and inter-scan repeatability. Simulations indicated that noise in magnitude images resulted in <6% bias in diffusion coefficients and non-Gaussian parameters (α, K), whereas baseline fitting minimized fat bias for all models, except IVIM. In vivo, popular SPAIR fat suppression proved inadequate for accurate parameter estimation, producing non-physiological parameter estimates without baseline fitting and large biases when it was used. Combining all three fat suppression techniques and fitting data with a baseline offset gave the best results of all the methods studied for both Gaussian diffusion and, overall, for non-Gaussian diffusion. It produced consistent parameter estimates for all models, except IVIM, and highlighted non-Gaussian behavior perpendicular to muscle fibers (�

Geometrical Solutions of Quadratic Equations.

ERIC Educational Resources Information Center

Grewal, A. S.; Godloza, L.

1999-01-01

Demonstrates that the equation of a circle (x-h)2 + (y-k)2 = r2 with center (h; k) and radius r reduces to a quadratic equation x2-2xh + (h2 + k2 -r2) = O at the intersection with the x-axis. Illustrates how to determine the center of a circle as well as a point on a circle. (Author/ASK)

Gaussian-Beam Laser-Resonator Program

NASA Technical Reports Server (NTRS)

Cross, Patricia L.; Bair, Clayton H.; Barnes, Norman

1989-01-01

Gaussian Beam Laser Resonator Program models laser resonators by use of Gaussian-beam-propagation techniques. Used to determine radii of beams as functions of position in laser resonators. Algorithm used in program has three major components. First, ray-transfer matrix for laser resonator must be calculated. Next, initial parameters of beam calculated. Finally, propagation of beam through optical elements computed. Written in Microsoft FORTRAN (Version 4.01).

Gaussian maximally multipartite-entangled states

NASA Astrophysics Data System (ADS)

Facchi, Paolo; Florio, Giuseppe; Lupo, Cosmo; Mancini, Stefano; Pascazio, Saverio

2009-12-01

We study maximally multipartite-entangled states in the context of Gaussian continuous variable quantum systems. By considering multimode Gaussian states with constrained energy, we show that perfect maximally multipartite-entangled states, which exhibit the maximum amount of bipartite entanglement for all bipartitions, only exist for systems containing n=2 or 3 modes. We further numerically investigate the structure of these states and their frustration for n≤7 .

Cerium dioxide (CeO2) nanoparticles decrease arsenite (As(III)) cytotoxicity to 16HBE14o- human bronchial epithelial cells.

PubMed

Zeng, Chao; Nguyen, Chi; Boitano, Scott; Field, Jim A; Shadman, Farhang; Sierra-Alvarez, Reyes

2018-07-01

The production and application of engineered nanoparticles (NPs) are increasing in demand with the rapid development of nanotechnology. However, there are concerns that some of these novel materials could lead to emerging environmental and health problems. Some NPs are able to facilitate the transport of contaminants into cells/organisms via a "Trojan Horse" effect which enhances the toxicity of the adsorbed materials. In this work, we evaluated the toxicity of arsenite (As(III)) adsorbed onto cerium dioxide (CeO 2 ) NPs to human bronchial epithelial cells (16HBE14o-) using the xCELLigence real time cell analyzing system (RTCA). Application of 0.5 mg/L As(III) resulted in 81.3% reduction of cell index (CI, an RTCA measure of cell toxicity) over 48 h when compared to control cells exposed to medium lacking As(III). However, when the cells were exposed to 0.5 mg/L As(III) in the presence of CeO 2 NPs (250 mg/L), the CI was only reduced by 12.9% compared to the control. The CeO 2 NPs had a high capacity for As(III) adsorption (20.2 mg/g CeO 2 ) in the bioassay medium, effectively reducing dissolved As(III) in the aqueous solution and resulting in reduced toxicity. Transmission electron microscopy was used to study the transport of CeO 2 NPs into 16HBE14o- cells. NP uptake via engulfment was observed and the internalized NPs accumulated in vesicles. The results demonstrate that dissolved As(III) in the aqueous solution was the decisive factor controlling As(III) toxicity of 16HBE14o- cells, and that CeO 2 NPs effectively reduced available As(III) through adsorption. These data emphasize the evaluation of mixtures when assaying toxicity. Copyright © 2018 Elsevier Inc. All rights reserved.

Strong performance. Healthcare executives reaped big rewards in 2010, with returning hospital CEOs seeing a 58.2% gain in compensation.

PubMed

Galloro, Vince

2011-08-15

Healthcare CEOs saw their compensation slip relative to other industries but still earned big paydays last year. "2010 was a great year for corporate earnings and stock performance," says Steve Kaplan, left, a professor of finance and entrepreneurship. "Part of the reason for the increase in pay is that the CEOs delivered in 2010."

Loop corrections to primordial non-Gaussianity

NASA Astrophysics Data System (ADS)

Boran, Sibel; Kahya, E. O.

2018-02-01

We discuss quantum gravitational loop effects to observable quantities such as curvature power spectrum and primordial non-Gaussianity of cosmic microwave background (CMB) radiation. We first review the previously shown case where one gets a time dependence for zeta-zeta correlator due to loop corrections. Then we investigate the effect of loop corrections to primordial non-Gaussianity of CMB. We conclude that, even with a single scalar inflaton, one might get a huge value for non-Gaussianity which would exceed the observed value by at least 30 orders of magnitude. Finally we discuss the consequences of this result for scalar driven inflationary models.

Variational Gaussian approximation for Poisson data

NASA Astrophysics Data System (ADS)

Arridge, Simon R.; Ito, Kazufumi; Jin, Bangti; Zhang, Chen

2018-02-01

The Poisson model is frequently employed to describe count data, but in a Bayesian context it leads to an analytically intractable posterior probability distribution. In this work, we analyze a variational Gaussian approximation to the posterior distribution arising from the Poisson model with a Gaussian prior. This is achieved by seeking an optimal Gaussian distribution minimizing the Kullback-Leibler divergence from the posterior distribution to the approximation, or equivalently maximizing the lower bound for the model evidence. We derive an explicit expression for the lower bound, and show the existence and uniqueness of the optimal Gaussian approximation. The lower bound functional can be viewed as a variant of classical Tikhonov regularization that penalizes also the covariance. Then we develop an efficient alternating direction maximization algorithm for solving the optimization problem, and analyze its convergence. We discuss strategies for reducing the computational complexity via low rank structure of the forward operator and the sparsity of the covariance. Further, as an application of the lower bound, we discuss hierarchical Bayesian modeling for selecting the hyperparameter in the prior distribution, and propose a monotonically convergent algorithm for determining the hyperparameter. We present extensive numerical experiments to illustrate the Gaussian approximation and the algorithms.

Large-scale velocities and primordial non-Gaussianity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidt, Fabian

2010-09-15

We study the peculiar velocities of density peaks in the presence of primordial non-Gaussianity. Rare, high-density peaks in the initial density field can be identified with tracers such as galaxies and clusters in the evolved matter distribution. The distribution of relative velocities of peaks is derived in the large-scale limit using two different approaches based on a local biasing scheme. Both approaches agree, and show that halos still stream with the dark matter locally as well as statistically, i.e. they do not acquire a velocity bias. Nonetheless, even a moderate degree of (not necessarily local) non-Gaussianity induces a significant skewnessmore » ({approx}0.1-0.2) in the relative velocity distribution, making it a potentially interesting probe of non-Gaussianity on intermediate to large scales. We also study two-point correlations in redshift space. The well-known Kaiser formula is still a good approximation on large scales, if the Gaussian halo bias is replaced with its (scale-dependent) non-Gaussian generalization. However, there are additional terms not encompassed by this simple formula which become relevant on smaller scales (k > or approx. 0.01h/Mpc). Depending on the allowed level of non-Gaussianity, these could be of relevance for future large spectroscopic surveys.« less

Effect of CeO2 addition on the properties of FeAl based alloy produced by mechanical alloying technique

NASA Astrophysics Data System (ADS)

Khaerudini, Deni S.; Muljadi, Sardjono, P.; Tetuko, Anggito P.; Sebayang, P.; Ginting, M.

2013-09-01

Iron aluminides based on FeAl is notable for their low materials cost, ease of fabrication and good corrosion, suffixation and oxidation resistance. However, the application based on these unique properties still require the development of Fe-Al based alloy since it shows some drawbacks such as a lack of high temperature strength and low ductility. To improve the mechanical properties of FeAl based alloy, ceria (CeO2) will be added to this compound. FeAl based alloy produced by the mechanical alloying (MA) technique. The developed specimens then assessed with respect to oxidation behaviour in high temperature, scale microstructure and hardness. The surface morphologies of the alloy evaluated and observed using scanning electron microscopy (SEM) with an energy dispersive X-ray spectroscopy (EDX). The phase structures of oxide scale formed on them were identified by X-ray diffraction (XRD). The results found that the FeAl intermetallic compound containing CeO2 0.5 wt.% is less pores and CeO2 1.0 wt.% is more homogen in powder and solid form, higher hardness and increase in their resistance to oxidation behaviour in high temperature compared with another percentage of CeO2.

Local Gaussian operations can enhance continuous-variable entanglement distillation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Shengli; Loock, Peter van; Institute of Theoretical Physics I, Universitaet Erlangen-Nuernberg, Staudtstrasse 7/B2, DE-91058 Erlangen

2011-12-15

Entanglement distillation is a fundamental building block in long-distance quantum communication. Though known to be useless on their own for distilling Gaussian entangled states, local Gaussian operations may still help to improve non-Gaussian entanglement distillation schemes. Here we show that by applying local squeezing operations both the performance and the efficiency of existing distillation protocols can be enhanced. We find that such an enhancement through local Gaussian unitaries can be obtained even when the initially shared Gaussian entangled states are mixed, as, for instance, after their distribution through a lossy-fiber communication channel.

The non-avian theropod quadrate I: standardized terminology with an overview of the anatomy and function

PubMed Central

Araújo, Ricardo; Mateus, Octávio

2015-01-01

The quadrate of reptiles and most other tetrapods plays an important morphofunctional role by allowing the articulation of the mandible with the cranium. In Theropoda, the morphology of the quadrate is particularly complex and varies importantly among different clades of non-avian theropods, therefore conferring a strong taxonomic potential. Inconsistencies in the notation and terminology used in discussions of the theropod quadrate anatomy have been noticed, including at least one instance when no less than eight different terms were given to the same structure. A standardized list of terms and notations for each quadrate anatomical entity is proposed here, with the goal of facilitating future descriptions of this important cranial bone. In addition, an overview of the literature on quadrate function and pneumaticity in non-avian theropods is presented, along with a discussion of the inferences that could be made from this research. Specifically, the quadrate of the large majority of non-avian theropods is akinetic but the diagonally oriented intercondylar sulcus of the mandibular articulation allowed both rami of the mandible to move laterally when opening the mouth in many of theropods. Pneumaticity of the quadrate is also present in most averostran clades and the pneumatic chamber—invaded by the quadrate diverticulum of the mandibular arch pneumatic system—was connected to one or several pneumatic foramina on the medial, lateral, posterior, anterior or ventral sides of the quadrate. PMID:26401455

Gaussian ancillary bombardment

NASA Astrophysics Data System (ADS)

Grimmer, Daniel; Brown, Eric; Kempf, Achim; Mann, Robert B.; Martín-Martínez, Eduardo

2018-05-01

We analyze in full detail the time evolution of an open Gaussian quantum system rapidly bombarded by Gaussian ancillae. As a particular case this analysis covers the thermalization (or not) of a harmonic oscillator coupled to a thermal reservoir made of harmonic oscillators. We derive general results for this scenario and apply them to the problem of thermalization. We show that only a particular family of system-environment couplings will cause the system to thermalize to the temperature of its environment. We discuss that if we want to understand thermalization as ensuing from the Markovian interaction of a system with the individual microconstituents of its (thermal) environment then the process of thermalization is not as robust as one might expect.

CNO to CEO: Barbara A. Donaho and Irma E. Goertzen--they broke the glass ceiling. Interview by Barbara J Brown.

PubMed

Donaho, B A; Goertzen, I E

1995-01-01

Two nurse executives who broke the glass ceiling to become chief executives of health care systems are interviewed. Irma Goertzen and Barbara Donaho are asked key, candid questions comparing chief nurse officer (CNO) with chief executive officer (CEO); special skills needed; being a woman in a traditional man's role; and advice to colleagues for becoming a CEO.

Colloidal stability of CeO2 nanoparticles coated with either natural organic matter or organic polymers under various hydrochemical conditions

NASA Astrophysics Data System (ADS)

Dippon, Urs; Pabst, Silke; Klitzke, Sondra

2016-04-01

The worldwide marked for engineered nanoparticles (ENPs) is growing and concerns on the environmental fate- and toxicity of ENPs are rising. Understanding the transport of ENPs within and between environmental compartments such as surface water and groundwater is crucial for exposition modeling, risk assessment and ultimately the protection of drinking water resources. The transport of ENPs is strongly influenced by the surface properties and aggregation behavior of the particles, which is strongly controlled by synthetic and natural organic coatings. Both, surface properties and aggregation characteristics are also key properties for the industrial application of ENPs, which leads to the development and commercialization of an increasing number of surface-functionalized ENPs. These include metals and oxides such as Cerium dioxide (CeO2) with various organic coatings. Therefore, we investigate CeO2 ENPs with different surface coatings such as weakly anionic polyvinyl alcohol (PVA) or strongly anionic poly acrylic acid (PAA) with respect to their colloidal stability in aqueous matrix under various hydrochemical conditions (pH, ionic strength) and their transport behavior in sand filter columns. Furthermore, we investigate the interaction of naturally occurring organic matter (NOM) with CeO2 ENPs and its effect on surface charge (zeta potential), colloidal stability and transport. While uncoated CeO2 ENPs aggregate at pH > 4 in aqueous matrix, our results show that PAA and PVA surface coatings as well as NOM sorbed to CeO2-NP surfaces can stabilize CeO2 ENPs under neutral and alkaline pH conditions in 1 mM KCl solution. Under slightly acidic conditions, differences between the three particle types were observed. PVA can stabilize particle suspensions in presence of 1 mM KCl at pH > 4.3, PAA at pH >4.0 and NOM at >3.2. While the presence of KCl did not influence particle size of NOM-CeO2 ENPs, CaCl2 at >2 mM lead to aggregation. Further results on the influence of KCl

GaussianCpG: a Gaussian model for detection of CpG island in human genome sequences.

PubMed

Yu, Ning; Guo, Xuan; Zelikovsky, Alexander; Pan, Yi

2017-05-24

As crucial markers in identifying biological elements and processes in mammalian genomes, CpG islands (CGI) play important roles in DNA methylation, gene regulation, epigenetic inheritance, gene mutation, chromosome inactivation and nuclesome retention. The generally accepted criteria of CGI rely on: (a) %G+C content is ≥ 50%, (b) the ratio of the observed CpG content and the expected CpG content is ≥ 0.6, and (c) the general length of CGI is greater than 200 nucleotides. Most existing computational methods for the prediction of CpG island are programmed on these rules. However, many experimentally verified CpG islands deviate from these artificial criteria. Experiments indicate that in many cases %G+C is < 50%, CpG obs /CpG exp varies, and the length of CGI ranges from eight nucleotides to a few thousand of nucleotides. It implies that CGI detection is not just a straightly statistical task and some unrevealed rules probably are hidden. A novel Gaussian model, GaussianCpG, is developed for detection of CpG islands on human genome. We analyze the energy distribution over genomic primary structure for each CpG site and adopt the parameters from statistics of Human genome. The evaluation results show that the new model can predict CpG islands efficiently by balancing both sensitivity and specificity over known human CGI data sets. Compared with other models, GaussianCpG can achieve better performance in CGI detection. Our Gaussian model aims to simplify the complex interaction between nucleotides. The model is computed not by the linear statistical method but by the Gaussian energy distribution and accumulation. The parameters of Gaussian function are not arbitrarily designated but deliberately chosen by optimizing the biological statistics. By using the pseudopotential analysis on CpG islands, the novel model is validated on both the real and artificial data sets.

Apertured averaged scintillation of fully and partially coherent Gaussian, annular Gaussian, flat toped and dark hollow beams

NASA Astrophysics Data System (ADS)

Eyyuboğlu, Halil T.

2015-03-01

Apertured averaged scintillation requires the evaluation of rather complicated irradiance covariance function. Here we develop a much simpler numerical method based on our earlier introduced semi-analytic approach. Using this method, we calculate aperture averaged scintillation of fully and partially coherent Gaussian, annular Gaussian flat topped and dark hollow beams. For comparison, the principles of equal source beam power and normalizing the aperture averaged scintillation with respect to received power are applied. Our results indicate that for fully coherent beams, upon adjusting the aperture sizes to capture 10 and 20% of the equal source power, Gaussian beam needs the largest aperture opening, yielding the lowest aperture average scintillation, whilst the opposite occurs for annular Gaussian and dark hollow beams. When assessed on the basis of received power normalized aperture averaged scintillation, fixed propagation distance and aperture size, annular Gaussian and dark hollow beams seem to have the lowest scintillation. Just like the case of point-like scintillation, partially coherent beams will offer less aperture averaged scintillation in comparison to fully coherent beams. But this performance improvement relies on larger aperture openings. Upon normalizing the aperture averaged scintillation with respect to received power, fully coherent beams become more advantageous than partially coherent ones.

A Wavelet Bicoherence-Based Quadratic Nonlinearity Feature for Translational Axis Condition Monitoring

PubMed Central

Li, Yong; Wang, Xiufeng; Lin, Jing; Shi, Shengyu

2014-01-01

The translational axis is one of the most important subsystems in modern machine tools, as its degradation may result in the loss of the product qualification and lower the control precision. Condition-based maintenance (CBM) has been considered as one of the advanced maintenance schemes to achieve effective, reliable and cost-effective operation of machine systems, however, current vibration-based maintenance schemes cannot be employed directly in the translational axis system, due to its complex structure and the inefficiency of commonly used condition monitoring features. In this paper, a wavelet bicoherence-based quadratic nonlinearity feature is proposed for translational axis condition monitoring by using the torque signature of the drive servomotor. Firstly, the quadratic nonlinearity of the servomotor torque signature is discussed, and then, a biphase randomization wavelet bicoherence is introduced for its quadratic nonlinear detection. On this basis, a quadratic nonlinearity feature is proposed for condition monitoring of the translational axis. The properties of the proposed quadratic nonlinearity feature are investigated by simulations. Subsequently, this feature is applied to the real-world servomotor torque data collected from the X-axis on a high precision vertical machining centre. All the results show that the performance of the proposed feature is much better than that of original condition monitoring features. PMID:24473281

NGMIX: Gaussian mixture models for 2D images

NASA Astrophysics Data System (ADS)

Sheldon, Erin

2015-08-01

NGMIX implements Gaussian mixture models for 2D images. Both the PSF profile and the galaxy are modeled using mixtures of Gaussians. Convolutions are thus performed analytically, resulting in fast model generation as compared to methods that perform the convolution in Fourier space. For the galaxy model, NGMIX supports exponential disks and de Vaucouleurs and Sérsic profiles; these are implemented approximately as a sum of Gaussians using the fits from Hogg & Lang (2013). Additionally, any number of Gaussians can be fit, either completely free or constrained to be cocentric and co-elliptical.

Development and modification of a Gaussian and non-Gaussian noise exposure system

NASA Astrophysics Data System (ADS)

Schlag, Adam W.

Millions of people across the world currently have noise induced hearing loss, and many are working in conditions with both continuous Gaussian and non-Gaussian noises that could affect their hearing. It was hypothesized that the energy of the noise was the cause of the hearing loss and did not depend on temporal pattern of a noise. This was referred to as the equal energy hypothesis. This hypothesis has been shown to have limitations though. This means that there is a difference in the types of noise a person receives to induce hearing loss and it is necessary to build a system that can easily mimic various conditions to conduct research. This study builds a system that can produce both non-Gaussian impulse/impact noises and continuous Gaussian noise. It was found that the peak sound pressure level of the system could reach well above the needed 120 dB level to represent acoustic trauma and could replicate well above the 85 dB A-weighted sound pressure level to produce conditions of gradual developing hearing loss. The system reached a maximum of 150 dB sound peak pressure level and a maximum of 133 dB A-weighted sound pressure level. Various parameters could easily be adjusted to control the sound, such as the high and low cutoff frequency to center the sound at 4 kHz. The system build can easily be adjusted to create numerous sound conditions and will hopefully be modified and improved in hopes of eventually being used for animal studies to lead to the creation of a method to treat or prevent noise induced hearing loss.

Stress response and tolerance of Zea mays to CeO2 nanoparticles: cross talk among H2O2, heat shock protein, and lipid peroxidation.

PubMed

Zhao, Lijuan; Peng, Bo; Hernandez-Viezcas, Jose A; Rico, Cyren; Sun, Youping; Peralta-Videa, Jose R; Tang, Xiaolei; Niu, Genhua; Jin, Lixin; Varela-Ramirez, Armando; Zhang, Jian-ying; Gardea-Torresdey, Jorge L

2012-11-27

The rapid development of nanotechnology will inevitably release nanoparticles (NPs) into the environment with unidentified consequences. In addition, the potential toxicity of CeO(2) NPs to plants and the possible transfer into the food chain are still unknown. Corn plants (Zea mays) were germinated and grown in soil treated with CeO(2) NPs at 400 or 800 mg/kg. Stress-related parameters, such as H(2)O(2), catalase (CAT), and ascorbate peroxidase (APX) activity, heat shock protein 70 (HSP70), lipid peroxidation, cell death, and leaf gas exchange were analyzed at 10, 15, and 20 days post-germination. Confocal laser scanning microscopy was used to image H(2)O(2) distribution in corn leaves. Results showed that the CeO(2) NP treatments increased accumulation of H(2)O(2), up to day 15, in phloem, xylem, bundle sheath cells and epidermal cells of shoots. The CAT and APX activities were also increased in the corn shoot, concomitant with the H(2)O(2) levels. Both 400 and 800 mg/kg CeO(2) NPs triggered the up-regulation of the HSP70 in roots, indicating a systemic stress response. None of the CeO(2) NPs increased the level of thiobarbituric acid reacting substances, indicating that no lipid peroxidation occurred. CeO(2) NPs, at both concentrations, did not induce ion leakage in either roots or shoots, suggesting that membrane integrity was not compromised. Leaf net photosynthetic rate, transpiration, and stomatal conductance were not affected by CeO(2) NPs. Our results suggest that the CAT, APX, and HSP70 might help the plants defend against CeO(2) NP-induced oxidative injury and survive NP exposure.

Stress Response and Tolerance of Zea mays to CeO2 Nanoparticles: Cross Talk among H2O2, Heat Shock Protein and Lipid Peroxidation

PubMed Central

Zhao, Lijuan; Peng, Bo; Hernandez-Viezcas, Jose A.; Rico, Cyren; Sun, Youping; Peralta-Videa, Jose R.; Tang, Xiaolei; Niu, Genhua; Jin, Lixin; Varela-Ramirez, Armando; Zhang, Jian-ying; Gardea-Torresdey, Jorge L.

2014-01-01

The rapid development of nanotechnology will inevitably release nanoparticles (NPs) into the environment with unidentified consequences. In addition, the potential toxicity of CeO2 NPs to plants, and the possible transfer into the food chain, are still unknown. Corn plants (Zea mays) were germinated and grown in soil treated with CeO2 NPs at 400 or 800 mg/kg. Stress related parameters, such as: H2O2, catalase (CAT) and ascorbate peroxidase (APX) activity, heat shock protein 70 (HSP 70), lipid peroxidation, cell death and leaf gas exchange were analyzed at 10, 15, and 20 days post germination. Confocal laser scanning microscopy was used to image H2O2 distribution in corn leaves. Results showed that the CeO2 NP treatments increased accumulation of H2O2, up to day 15, in phloem, xylem, bundle sheath cells, and epidermal cells of shoots. The CAT and APX activities were also increased in the corn shoot, concomitant with the H2O2 levels. Both 400 and 800 mg/kg CeO2 NPs triggered the up regulation of the HSP 70 in roots, indicating a systemic stress response. None of the CeO2 NPs increased the level of thiobarbituric acid reacting substances, indicating that no lipid peroxidation occurred. CeO2 NPs, at both concentrations, did not induce ion leakage in either roots or shoots, suggesting membrane integrity was not compromised. Leaf net photosynthetic rate, transpiration, and stomatal conductance were not affected by CeO2 NPs. Our results suggest that the CAT, APX and HSP 70 might help the plants defend against CeO2 NPs induced oxidative injury and survive NP exposure. PMID:23050848

Super-resolving random-Gaussian apodized photon sieve.

PubMed

Sabatyan, Arash; Roshaninejad, Parisa

2012-09-10

A novel apodized photon sieve is presented in which random dense Gaussian distribution is implemented to modulate the pinhole density in each zone. The random distribution in dense Gaussian distribution causes intrazone discontinuities. Also, the dense Gaussian distribution generates a substantial number of pinholes in order to form a large degree of overlap between the holes in a few innermost zones of the photon sieve; thereby, clear zones are formed. The role of the discontinuities on the focusing properties of the photon sieve is examined as well. Analysis shows that secondary maxima have evidently been suppressed, transmission has increased enormously, and the central maxima width is approximately unchanged in comparison to the dense Gaussian distribution. Theoretical results have been completely verified by experiment.

Gaussian intrinsic entanglement for states with partial minimum uncertainty

NASA Astrophysics Data System (ADS)

Mišta, Ladislav; Baksová, Klára

2018-01-01

We develop a recently proposed theory of a quantifier of bipartite Gaussian entanglement called Gaussian intrinsic entanglement (GIE) [L. Mišta, Jr. and R. Tatham, Phys. Rev. Lett. 117, 240505 (2016), 10.1103/PhysRevLett.117.240505]. Gaussian intrinsic entanglement provides a compromise between computable and physically meaningful entanglement quantifiers and so far it has been calculated for two-mode Gaussian states including all symmetric partial minimum-uncertainty states, weakly mixed asymmetric squeezed thermal states with partial minimum uncertainty, and weakly mixed symmetric squeezed thermal states. We improve the method of derivation of GIE and show that all previously derived formulas for GIE of weakly mixed states in fact hold for states with higher mixedness. In addition, we derive analytical formulas for GIE for several other classes of two-mode Gaussian states with partial minimum uncertainty. Finally, we show that, like for all previously known states, also for all currently considered states the GIE is equal to Gaussian Rényi-2 entanglement of formation. This finding strengthens a conjecture about the equivalence of GIE and Gaussian Rényi-2 entanglement of formation for all bipartite Gaussian states.

Quadratic canonical transformation theory and higher order density matrices.

PubMed

Neuscamman, Eric; Yanai, Takeshi; Chan, Garnet Kin-Lic

2009-03-28

Canonical transformation (CT) theory provides a rigorously size-extensive description of dynamic correlation in multireference systems, with an accuracy superior to and cost scaling lower than complete active space second order perturbation theory. Here we expand our previous theory by investigating (i) a commutator approximation that is applied at quadratic, as opposed to linear, order in the effective Hamiltonian, and (ii) incorporation of the three-body reduced density matrix in the operator and density matrix decompositions. The quadratic commutator approximation improves CT's accuracy when used with a single-determinant reference, repairing the previous formal disadvantage of the single-reference linear CT theory relative to singles and doubles coupled cluster theory. Calculations on the BH and HF binding curves confirm this improvement. In multireference systems, the three-body reduced density matrix increases the overall accuracy of the CT theory. Tests on the H(2)O and N(2) binding curves yield results highly competitive with expensive state-of-the-art multireference methods, such as the multireference Davidson-corrected configuration interaction (MRCI+Q), averaged coupled pair functional, and averaged quadratic coupled cluster theories.

Differences between quadratic equations and functions: Indonesian pre-service secondary mathematics teachers’ views

NASA Astrophysics Data System (ADS)

Aziz, T. A.; Pramudiani, P.; Purnomo, Y. W.

2018-01-01

Difference between quadratic equation and quadratic function as perceived by Indonesian pre-service secondary mathematics teachers (N = 55) who enrolled at one private university in Jakarta City was investigated. Analysis of participants’ written responses and interviews were conducted consecutively. Participants’ written responses highlighted differences between quadratic equation and function by referring to their general terms, main characteristics, processes, and geometrical aspects. However, they showed several obstacles in describing the differences such as inappropriate constraints and improper interpretations. Implications of the study are discussed.

Hydrophilic CeO2 nanocubes protect pancreatic β-cell line INS-1 from H2O2-induced oxidative stress

NASA Astrophysics Data System (ADS)

Lyu, Guang-Ming; Wang, Yan-Jie; Huang, Xue; Zhang, Huai-Yuan; Sun, Ling-Dong; Liu, Yan-Jun; Yan, Chun-Hua

2016-04-01

Oxidative stress plays a key role in the occurrence and development of diabetes. With their unique redox properties, CeO2 nanoparticles (nanoceria) exhibit promising potential for the treatment of diabetes resulting from oxidative stress. Here, we develop a novel preparation of hydrophilic CeO2 nanocubes (NCs) with two different sizes (5 nm and 25 nm) via an acetate assisted hydrothermal method. Dynamic light scattering, zeta potential measurements and thermogravimetric analyses were utilized to investigate the changes in the physico-chemical characteristics of CeO2 NCs when exposed to in vitro cell culture conditions. CCK-8 assays revealed that the CeO2 NCs did not impair cell proliferation in the pancreatic β-cell line INS-1 at the highest dose of 200 μg mL-1 over the time scale of 72 h, while being able to protect INS-1 cells from H2O2-induced cytotoxicity even after protein adsorption. It is also noteworthy that nanoceria with a smaller hydrodynamic radius exhibit stronger antioxidant and anti-apoptotic effects, which is consistent with their H2O2 quenching capability in biological systems. These findings suggest that nanoceria can be used as an excellent antioxidant for controlling oxidative stress-induced pancreatic β-cell damage.Oxidative stress plays a key role in the occurrence and development of diabetes. With their unique redox properties, CeO2 nanoparticles (nanoceria) exhibit promising potential for the treatment of diabetes resulting from oxidative stress. Here, we develop a novel preparation of hydrophilic CeO2 nanocubes (NCs) with two different sizes (5 nm and 25 nm) via an acetate assisted hydrothermal method. Dynamic light scattering, zeta potential measurements and thermogravimetric analyses were utilized to investigate the changes in the physico-chemical characteristics of CeO2 NCs when exposed to in vitro cell culture conditions. CCK-8 assays revealed that the CeO2 NCs did not impair cell proliferation in the pancreatic β-cell line INS-1 at

Structure and photoluminescence studies of CeO2·CuAlO2 mixed metal oxide fabricated by co-precipitation method

NASA Astrophysics Data System (ADS)

Subhan, Md Abdus; Ahmed, Tanzir; Awal, M. R.; Kim, B. Moon

2015-01-01

A novel mixed metal oxide, CeO2·CuAlO2 was fabricated by co-precipitation method in aqueous medium. CeO2·CuAlO2 was characterized by XRD, SEM, EDS, TEM, FTIR and PL spectra. The optical properties of the nanoparticles were studied by photoluminescence (PL) spectra. PL spectra at different excitations were recorded. The composite showed emission in UV, visible and NIR region depending on the excitation wavelength. The special spectral feature observed for this composite is that it showed six emission bands at 364, 409, 434, 448, 465 and 481 nm when excited at 298 nm. The green and red emissions observed at 512 and 669 nm are originated from cubic CeO2 phase when excited at 450 nm. The PL spectra were found to be dependent on excitation wavelength violating Kasha's rule. The X-ray diffraction reveals a cubic CeO2 phase and hexagonal CuAlO2 phase. EDS spectra revealed the presence of cerium (Ce), copper (Cu), aluminum (Al) and oxygen (O) elements. The particle size of the CeO2·CuAlO2 mixed oxide was estimated using Scherrer's formula, which was found to be in the range of 17.2-34.2 nm. The TEM image showed particles are almost uniform size of approximately 15-50 nm with spherical morphology.

Synthesis and characterization of binary (CuO)0.6(CeO2)0.4 nanoparticles via a simple heat treatment method

NASA Astrophysics Data System (ADS)

Baqer, Anwar Ali; Matori, Khamirul Amin; Al-Hada, Naif Mohammed; Shaari, Abdul Halim; Kamari, Halimah Mohamed; Saion, Elias; Chyi, Josephine Liew Ying; Abdullah, Che Azurahanim Che

2018-06-01

A binary (CuO)0.6 (CeO2)0.4 nanoparticles were prepared via thermal treatment method, using copper nitrate, cerium nitrate as precursors, PVP as capping agent and de-ionized water as a solvent. The structures, morphology, composition of the element and optical properties of these nanoparticles have been studied under different temperatures using various techniques. The XRD spectrum of the samples at 500 °C and above confirmed the existence of both monoclinic (CuO) and cubic fluorite (CeO2) structures. The findings of FESEM and TEM exhibited the average practical size and agglomeration increment with an elevation in the calcination temperature. The synthesized nanoparticles were also characterized by FTIR, which indicated the formation of binary Cu-O and Ce-O bonds. The EDX analysis was performed to indicate the chemical composition of the sample. The double energy band gaps of (CuO)0.6(CeO2)0.4 reduction with rising calcination temperature, can be referred to the enhancement of the crystallinity of the samples. PL intensity of (CuO)0.6(CeO2)0.4 nanoparticles peaks, which increased with the elevation of the calcination temperature to 800 °C was observed from the PL spectrum; this was due to the increment of the particle size that occurred.

GAUSSIAN BEAM LASER RESONATOR PROGRAM

NASA Technical Reports Server (NTRS)

Cross, P. L.

1994-01-01

In designing a laser cavity, the laser engineer is frequently concerned with more than the stability of the resonator. Other considerations include the size of the beam at various optical surfaces within the resonator or the performance of intracavity line-narrowing or other optical elements. Laser resonators obey the laws of Gaussian beam propagation, not geometric optics. The Gaussian Beam Laser Resonator Program models laser resonators using Gaussian ray trace techniques. It can be used to determine the propagation of radiation through laser resonators. The algorithm used in the Gaussian Beam Resonator program has three major components. First, the ray transfer matrix for the laser resonator must be calculated. Next calculations of the initial beam parameters, specifically, the beam stability, the beam waist size and location for the resonator input element, and the wavefront curvature and beam radius at the input surface to the first resonator element are performed. Finally the propagation of the beam through the optical elements is computed. The optical elements can be modeled as parallel plates, lenses, mirrors, dummy surfaces, or Gradient Index (GRIN) lenses. A Gradient Index lens is a good approximation of a laser rod operating under a thermal load. The optical system may contain up to 50 elements. In addition to the internal beam elements the optical system may contain elements external to the resonator. The Gaussian Beam Resonator program was written in Microsoft FORTRAN (Version 4.01). It was developed for the IBM PS/2 80-071 microcomputer and has been implemented on an IBM PC compatible under MS DOS 3.21. The program was developed in 1988 and requires approximately 95K bytes to operate.

Surface-structure sensitivity of CeO 2 nanocrystals in photocatalysis and enhancing the reactivity with nanogold

DOE PAGES

Lei, Wanying; Zhang, Tingting; Gu, Lin; ...

2015-06-19

Structure–function correlations are a central theme in heterogeneous (photo)catalysis. In this research, using aberration-corrected scanning transmission electron microscopy (STEM), the atomic surface structures of well-defined one-dimensional (1D) CeO 2 nanorods (NRs) and 3D nanocubes (NCs) are directly visualized at subangstrom resolution. CeO 2 NCs predominantly expose the {100} facet, with {110} and {111} as minor cutoff facets at the respective edges and corners. Notably, the outermost surface layer of the {100} facet is nearly O-terminated. Neither surface relaxations nor reconstructions on {100} are observed, indicating unusual polarity compensation, which is primarily mediated by near-surface oxygen vacancies. The surface of CeOmore » 2 NRs is highly stepped, with the enclosed {110} facet exposing Ce cations and O anions on terraces. On the basis of STEM profile-view imaging and electronic structure analysis, the photoreactivity of CeO2 nanocrystals toward aqueous methyl orange degradation under UV is revealed to be surface-structure-sensitive, following the order: {110} >> {100}. The underlying surface-structure sensitivity can be attributed to the variation in low-coordinate surface cerium cations between {110} and {100} facets. To further enhance light absorption, Au nanoparticles (NPs) are deposited on CeO 2 NRs to form Au/CeO 2 plasmonic nanocomposites, which dramatically promotes the photoreactivity that is Au particle size- and excitation light wavelength-dependent. The mechanisms responsible for the enhancement of photocatalytic activity are discussed, highlighting the crucial role of photoexcited charge carrier transfer.« less

Update on Activities of CEOS Disaster Management Support Group

NASA Astrophysics Data System (ADS)

Wood, H. M.; Lauritson, L.

The Committee on Earth Observation Satellites (CEOS) Disaster Management Support Group (DMSG) has supported natural and technological disaster management on a worldwide basis by fostering improved utilization of existing and planned Earth Observation (EO) satellite data. The DMSG has focused on developing and refining recommendations for the application of satellite data to selected hazard areas--drought, earthquake, fire, flood, ice, landslide, oil spill, and volcanic hazards. Particular emphasis was placed on working closely with space agencies, international and regional organizations, and commercial organizations on the implementation of these recommendations. The DMSG is in its last year with its primary focus on documenting its work and migrating on going activities to other fora. With over 300 participants from more than 140 organizations, the DMSG has found strong support among CEOS space agencies and the Integrated Global Observing Strategy (IGOS), as well as an enthusiastic reception from numerous international, regional, and national emergency managers, and distinct interest from the commercial sector. In addition, the group has worked to give full support to the work of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) in pursuit of decisions taken at UNISPACE III and the United Nations International Strategy on Disaster Reduction (ISDR). In conjunction with the IGOS, several of the DMSG hazards teams (earthquake, landslide, and solid Earth dimensions of volcanoes) are joining in the effort to develop an IGOS Geohazards theme team. Cooperation efforts with organizations such as IGOS, COPUOS, and ISDR will hopefully lead to the pick up of much of the on going DMSG activities. Since the inception of this ad hoc working group and its predecessor project, the DMSG has developed and refined recommendations for the application of satellite data by bringing together experts from eight hazard areas to identify user needs, as well as

Room temperature synthesis and enhanced photocatalytic property of CeO2/ZnO heterostructures

NASA Astrophysics Data System (ADS)

Wang, Chao; Fan, Huiqing; Ren, Xiaohu; Fang, Jiawen

2018-02-01

To achieve better photocatalytic performance, we proposed a facile solid-state reaction method to produce CeO2/ZnO heterostructures. Ceria and zinc oxide were synthesized simultaneously by thoroughly grinding the mixture of zinc acetate dihydrate, cerium nitrate hexahydrate and sodium hydroxide. The morphology of the as-prepared heterostructures varies dramatically as different amount of ceria was introduced in the composition. The photocatalytic performance of CeO2/ZnO heterojunctions was 4.6 times higher than that of pure ZnO. The enhanced photocatalytic activity could be ascribed to that more electrons and holes could transport to the surface of catalysts and react with the pollution due to the extended light-responsive range, accelerated migration, increased specific surface area and suppressed recombination of photogenerated carriers.

Smoothing optimization of supporting quadratic surfaces with Zernike polynomials

NASA Astrophysics Data System (ADS)

Zhang, Hang; Lu, Jiandong; Liu, Rui; Ma, Peifu

2018-03-01

A new optimization method to get a smooth freeform optical surface from an initial surface generated by the supporting quadratic method (SQM) is proposed. To smooth the initial surface, a 9-vertex system from the neighbor quadratic surface and the Zernike polynomials are employed to establish a linear equation system. A local optimized surface to the 9-vertex system can be build by solving the equations. Finally, a continuous smooth optimization surface is constructed by stitching the above algorithm on the whole initial surface. The spot corresponding to the optimized surface is no longer discrete pixels but a continuous distribution.

Modified Gaussian influence function of deformable mirror actuators.

PubMed

Huang, Linhai; Rao, Changhui; Jiang, Wenhan

2008-01-07

A new deformable mirror influence function based on a Gaussian function is introduced to analyze the fitting capability of a deformable mirror. The modified expressions for both azimuthal and radial directions are presented based on the analysis of the residual error between a measured influence function and a Gaussian influence function. With a simplex search method, we further compare the fitting capability of our proposed influence function to fit the data produced by a Zygo interferometer with that of a Gaussian influence function. The result indicates that the modified Gaussian influence function provides much better performance in data fitting.

Gaussian Finite Element Method for Description of Underwater Sound Diffraction

NASA Astrophysics Data System (ADS)

Huang, Dehua

A new method for solving diffraction problems is presented in this dissertation. It is based on the use of Gaussian diffraction theory. The Rayleigh integral is used to prove the core of Gaussian theory: the diffraction field of a Gaussian is described by a Gaussian function. The parabolic approximation used by previous authors is not necessary to this proof. Comparison of the Gaussian beam expansion and Fourier series expansion reveals that the Gaussian expansion is a more general and more powerful technique. The method combines the Gaussian beam superposition technique (Wen and Breazeale, J. Acoust. Soc. Am. 83, 1752-1756 (1988)) and the Finite element solution to the parabolic equation (Huang, J. Acoust. Soc. Am. 84, 1405-1413 (1988)). Computer modeling shows that the new method is capable of solving for the sound field even in an inhomogeneous medium, whether the source is a Gaussian source or a distributed source. It can be used for horizontally layered interfaces or irregular interfaces. Calculated results are compared with experimental results by use of a recently designed and improved Gaussian transducer in a laboratory water tank. In addition, the power of the Gaussian Finite element method is demonstrated by comparing numerical results with experimental results from use of a piston transducer in a water tank.

Ceos Wgiss Common Framework for Wgiss Connected Data Assets

NASA Astrophysics Data System (ADS)

Enloe, Y.; Mitchell, A. E.; Albani, M.; Yapur, M.

2016-12-01

The Committee on Earth Observation Satellites (CEOS), established in 1984 to coordinate civil space-borne observations of the Earth, has been building through its Working Group on Information Systems and Services (WGISS), a common data framework to identify and connect data assets at member agencies. Some of these data assets are federated systems such as the CEOS WGISS Integrated Catalog (CWIC), the European Space Agency's FedEO (Federated Earth Observations Missions Access) system, and the International Directory Network (IDN) which is an international effort developed by NASA to assist researchers in locating information on available data sets. A system level team provides coordination and oversight to make this loosely coupled federated system function and evolve. WGISS has identified 2 search standards, the Open Geospatial Consortium (OGC) Catalog Services for the Web (CSW) and the CEOS OpenSearch Best Practices (which references the OGC OpenSearch Geo and Time Extensions and OGC OpenSearch Extension for Earth Observation) as well as an interoperable metadata standard (ISO 19115) for use within the WGISS Connected Assets. Data partners must register their data collections in the IDN using the Global Change Master Directory (GCMD) Keywords. Data partners need to support one of the 2 search standards and be able to map their internal metadata to the ISO 19115 metadata elements. All searchable data must have a data access path. Clients can offer search and access to all or a subset of the satellite data available through the WGISS Connected Data Assets. Clients can offer support for a 2-step search: (1) Discovery through collection search using platform, instrument, science keywords, etc. at the IDN and (2) Search granule metadata at data partners through CWIC or FedEO. There are more than a dozen international agencies that offer their data through the WGISS Federation or working on developing their connections. This list includes European Space Agency, NASA

The CEO's role in business model reinvention.

PubMed

Govindarajan, Vijay; Trimble, Chris

2011-01-01

Fending off new competitors is a perennial struggle for established companies. Govindarajan and Trimble, of Dartmouth's Tuck School of Business, explain why: Many corporations become too comfortable with their existing business models and neglect the necessary work of radically reinventing them. The authors map out an alternative in their "three boxes" framework. They argue that while a CEO manages the present (box 1), he or she must also selectively forget the past (box 2) in order to create the future (box 3). Infosys chairman N.R. Narayana Murthy mastered the three boxes to reinvigorate his company and greatly increased its changes of enduring for generations.

Estimating factors influencing the detection probability of semiaquatic freshwater snails using quadrat survey methods

USGS Publications Warehouse

Roesler, Elizabeth L.; Grabowski, Timothy B.

2018-01-01

Developing effective monitoring methods for elusive, rare, or patchily distributed species requires extra considerations, such as imperfect detection. Although detection is frequently modeled, the opportunity to assess it empirically is rare, particularly for imperiled species. We used Pecos assiminea (Assiminea pecos), an endangered semiaquatic snail, as a case study to test detection and accuracy issues surrounding quadrat searches. Quadrats (9 × 20 cm; n = 12) were placed in suitable Pecos assiminea habitat and randomly assigned a treatment, defined as the number of empty snail shells (0, 3, 6, or 9). Ten observers rotated through each quadrat, conducting 5-min visual searches for shells. The probability of detecting a shell when present was 67.4 ± 3.0%, but it decreased with the increasing litter depth and fewer number of shells present. The mean (± SE) observer accuracy was 25.5 ± 4.3%. Accuracy was positively correlated to the number of shells in the quadrat and negatively correlated to the number of times a quadrat was searched. The results indicate quadrat surveys likely underrepresent true abundance, but accurately determine the presence or absence. Understanding detection and accuracy of elusive, rare, or imperiled species improves density estimates and aids in monitoring and conservation efforts.

Photon-phonon parametric oscillation induced by quadratic coupling in an optomechanical resonator

NASA Astrophysics Data System (ADS)

Zhang, Lin; Ji, Fengzhou; Zhang, Xu; Zhang, Weiping

2017-07-01

A direct photon-phonon parametric effect of quadratic coupling on the mean-field dynamics of an optomechanical resonator in the large-scale-movement regime is found and investigated. Under a weak pumping power, the mechanical resonator damps to a steady state with a nonlinear static response sensitively modified by the quadratic coupling. When the driving power increases beyond the static energy balance, the steady states lose their stabilities via Hopf bifurcations, and the resonator produces stable self-sustained oscillation (limit-circle behavior) of discrete energies with step-like amplitudes due to the parametric effect of quadratic coupling, which can be understood roughly by the power balance between gain and loss on the resonator. A further increase in the pumping power can induce a chaotic dynamic of the resonator via a typical routine of period-doubling bifurcation, but which can be stabilized by the parametric effect through an inversion-bifurcation process back to the limit-circle states. The bifurcation-to-inverse-bifurcation transitions are numerically verified by the maximal Lyapunov exponents of the dynamics, which indicate an efficient way of suppressing the chaotic behavior of the optomechanical resonator by quadratic coupling. Furthermore, the parametric effect of quadratic coupling on the dynamic transitions of an optomechanical resonator can be conveniently detected or traced by the output power spectrum of the cavity field.

Curious Consequences of a Miscopied Quadratic

ERIC Educational Resources Information Center

Poet, Jeffrey L.; Vestal, Donald L., Jr.

2005-01-01

The starting point of this article is a search for pairs of quadratic polynomials x[superscript 2] + bx plus or minus c with the property that they both factor over the integers. The search leads quickly to some number theory in the form of primitive Pythagorean triples, and this paper develops the connection between these two topics.

Evidence of the differential biotransformation and genotoxicity of ZnO and CeO2 nanoparticles on soybean (Glycine max) plants.

PubMed

López-Moreno, Martha L; de la Rosa, Guadalupe; Hernández-Viezcas, José A; Castillo-Michel, Hiram; Botez, Cristian E; Peralta-Videa, José R; Gardea-Torresdey, Jorge L

2010-10-01

Concern and interest related to the effects of nanomaterials on living organisms are growing in both the scientific and public communities. Reports have described the toxicity of nanoparticles (NPs) on micro- and macro-organisms, including some plant species. Nevertheless, to the authors' knowledge there are no reports on the biotransformation of NPs by edible terrestrial plants. Here, shown for the first time, is evidence pertaining to the biotransformation of ZnO and CeO(2) NPs in plant seedlings. Although the NPs did not affect soybean germination, they produced a differential effect on plant growth and element uptake. By using synchrotron X-ray absorption spectroscopy we obtained clear evidence of the presence of CeO(2) NPs in roots, whereas ZnO NPs were not present. Random amplified polymorphic DNA assay was applied to detect DNA damage and mutations caused by NPs. Results obtained from the exposure of soybean plants to CeO(2) NPs show the appearance of four new bands at 2000 mg L(-1) and three new bands at 4000 mg L(-1) treatment. In this study we demonstrated genotoxic effects from the exposure of soybean plants to CeO(2) NPs.

Gaussian entanglement distribution via satellite

NASA Astrophysics Data System (ADS)

Hosseinidehaj, Nedasadat; Malaney, Robert

2015-02-01

In this work we analyze three quantum communication schemes for the generation of Gaussian entanglement between two ground stations. Communication occurs via a satellite over two independent atmospheric fading channels dominated by turbulence-induced beam wander. In our first scheme, the engineering complexity remains largely on the ground transceivers, with the satellite acting simply as a reflector. Although the channel state information of the two atmospheric channels remains unknown in this scheme, the Gaussian entanglement generation between the ground stations can still be determined. On the ground, distillation and Gaussification procedures can be applied, leading to a refined Gaussian entanglement generation rate between the ground stations. We compare the rates produced by this first scheme with two competing schemes in which quantum complexity is added to the satellite, thereby illustrating the tradeoff between space-based engineering complexity and the rate of ground-station entanglement generation.

Analytical approximations for the oscillators with anti-symmetric quadratic nonlinearity

NASA Astrophysics Data System (ADS)

Alal Hosen, Md.; Chowdhury, M. S. H.; Yeakub Ali, Mohammad; Faris Ismail, Ahmad

2017-12-01

A second-order ordinary differential equation involving anti-symmetric quadratic nonlinearity changes sign. The behaviour of the oscillators with an anti-symmetric quadratic nonlinearity is assumed to oscillate different in the positive and negative directions. In this reason, Harmonic Balance Method (HBM) cannot be directly applied. The main purpose of the present paper is to propose an analytical approximation technique based on the HBM for obtaining approximate angular frequencies and the corresponding periodic solutions of the oscillators with anti-symmetric quadratic nonlinearity. After applying HBM, a set of complicated nonlinear algebraic equations is found. Analytical approach is not always fruitful for solving such kinds of nonlinear algebraic equations. In this article, two small parameters are found, for which the power series solution produces desired results. Moreover, the amplitude-frequency relationship has also been determined in a novel analytical way. The presented technique gives excellent results as compared with the corresponding numerical results and is better than the existing ones.

Revisiting non-Gaussianity from non-attractor inflation models

NASA Astrophysics Data System (ADS)

Cai, Yi-Fu; Chen, Xingang; Namjoo, Mohammad Hossein; Sasaki, Misao; Wang, Dong-Gang; Wang, Ziwei

2018-05-01

Non-attractor inflation is known as the only single field inflationary scenario that can violate non-Gaussianity consistency relation with the Bunch-Davies vacuum state and generate large local non-Gaussianity. However, it is also known that the non-attractor inflation by itself is incomplete and should be followed by a phase of slow-roll attractor. Moreover, there is a transition process between these two phases. In the past literature, this transition was approximated as instant and the evolution of non-Gaussianity in this phase was not fully studied. In this paper, we follow the detailed evolution of the non-Gaussianity through the transition phase into the slow-roll attractor phase, considering different types of transition. We find that the transition process has important effect on the size of the local non-Gaussianity. We first compute the net contribution of the non-Gaussianities at the end of inflation in canonical non-attractor models. If the curvature perturbations keep evolving during the transition—such as in the case of smooth transition or some sharp transition scenarios—the Script O(1) local non-Gaussianity generated in the non-attractor phase can be completely erased by the subsequent evolution, although the consistency relation remains violated. In extremal cases of sharp transition where the super-horizon modes freeze immediately right after the end of the non-attractor phase, the original non-attractor result can be recovered. We also study models with non-canonical kinetic terms, and find that the transition can typically contribute a suppression factor in the squeezed bispectrum, but the final local non-Gaussianity can still be made parametrically large.

Gender bias in hospital leadership: a qualitative study on the experiences of women CEOs.

PubMed

Soklaridis, Sophie; Kuper, Ayelet; Whitehead, Cynthia R; Ferguson, Genevieve; Taylor, Valerie H; Zahn, Catherine

2017-04-10

Purpose The purpose of this paper is to examine the experiences of gender bias among women hospital CEOs and explore to what these female leaders attribute their success within a male-dominated hospital executive leadership milieu. Design/methodology/approach This qualitative study involved 12 women hospital CEOs from across Ontario, Canada. Purposeful sampling techniques and in-depth qualitative interview methods were used to facilitate discussion around experiences of gender and leadership. Findings Responses fell into two groups: the first group represented the statement "Gender inequality is alive and well". The second group reflected the statement "Gender inequity is not significant, did not happen to me, and things are better now". This group contained a sub-group with no consciousness of systemic discrimination and that claimed having no gendered experiences in their leadership journey. The first group described gender issues in various contexts, from the individual to the systemic. The second group was ambivalent about gender as a factor impacting leadership trajectories. Originality/value Representations of women's leadership have become detached from feminism, with major consequences for women. This study reveals how difficult it is for some women CEOs to identify gender bias. The subtle everyday norms and practices within the workplace make it difficult to name and explain gender bias explicitly and may explain the challenges in understanding how it might affect a woman's career path.

Anomalous and non-Gaussian diffusion in Hertzian spheres

NASA Astrophysics Data System (ADS)

Ouyang, Wenze; Sun, Bin; Sun, Zhiwei; Xu, Shenghua

2018-09-01

By means of molecular dynamics simulations, we study the non-Gaussian diffusion in the fluid of Hertzian spheres. The time dependent non-Gaussian parameter, as an indicator of the dynamic heterogeneity, is increased with the increasing of temperature. When the temperature is high enough, the dynamic heterogeneity becomes very significant, and it seems counterintuitive that the maximum of non-Gaussian parameter and the position of its peak decrease monotonically with the increasing of density. By fitting the curves of self intermediate scattering function, we find that the character relaxation time τα is surprisingly not coupled with the time τmax where the non-Gaussian parameter reaches to a maximum. The intriguing features of non-Gaussian diffusion at high enough temperatures can be associated with the weakly correlated mean-field behavior of Hertzian spheres. Especially the time τmax is nearly inversely proportional to the density at extremely high temperatures.

A face only an investor could love: CEOs' facial structure predicts their firms' financial performance.

PubMed

Wong, Elaine M; Ormiston, Margaret E; Haselhuhn, Michael P

2011-12-01

Researchers have theorized that innate personal traits are related to leadership success. Although links between psychological characteristics and leadership success have been well established, research has yet to identify any objective physical traits of leaders that predict organizational performance. In the research reported here, we identified leaders' facial structure as a specific physical trait that correlates with organizational performance. Specifically, we found that firms whose male CEOs have wider faces (relative to facial height) achieve superior financial performance. Decision-making dynamics within a firm's leadership team moderate this effect, such that the relationship between a given CEO's facial measurements and his firm's financial performance is stronger in firms with cognitively simple leadership teams.

Propagation properties of cylindrical sinc Gaussian beam

NASA Astrophysics Data System (ADS)

Eyyuboğlu, Halil T.; Bayraktar, Mert

2016-09-01

We investigate the propagation properties of cylindrical sinc Gaussian beam in turbulent atmosphere. Since an analytic solution is hardly derivable, the study is carried out with the aid of random phase screens. Evolutions of the beam intensity profile, beam size and kurtosis parameter are analysed. It is found that on the source plane, cylindrical sinc Gaussian beam has a dark hollow appearance, where the side lobes also start to emerge with increase in width parameter and Gaussian source size. During propagation, beams with small width and Gaussian source size exhibit off-axis behaviour, losing the dark hollow shape, accumulating the intensity asymmetrically on one side, whereas those with large width and Gaussian source size retain dark hollow appearance even at long propagation distances. It is seen that the beams with large widths expand more in beam size than the ones with small widths. The structure constant values chosen do not seem to alter this situation. The kurtosis parameters of the beams having small widths are seen to be larger than the ones with the small widths. Again the choice of the structure constant does not change this trend.

Non-Gaussian Methods for Causal Structure Learning.

PubMed

Shimizu, Shohei

2018-05-22

Causal structure learning is one of the most exciting new topics in the fields of machine learning and statistics. In many empirical sciences including prevention science, the causal mechanisms underlying various phenomena need to be studied. Nevertheless, in many cases, classical methods for causal structure learning are not capable of estimating the causal structure of variables. This is because it explicitly or implicitly assumes Gaussianity of data and typically utilizes only the covariance structure. In many applications, however, non-Gaussian data are often obtained, which means that more information may be contained in the data distribution than the covariance matrix is capable of containing. Thus, many new methods have recently been proposed for using the non-Gaussian structure of data and inferring the causal structure of variables. This paper introduces prevention scientists to such causal structure learning methods, particularly those based on the linear, non-Gaussian, acyclic model known as LiNGAM. These non-Gaussian data analysis tools can fully estimate the underlying causal structures of variables under assumptions even in the presence of unobserved common causes. This feature is in contrast to other approaches. A simulated example is also provided.

Low toxicity of HfO2, SiO2, Al2O3 and CeO2 nanoparticles to the yeast, Saccharomyces cerevisiae.

PubMed

García-Saucedo, Citlali; Field, James A; Otero-Gonzalez, Lila; Sierra-Álvarez, Reyes

2011-09-15

Increasing use of nanomaterials necessitates an improved understanding of their potential impact on environment health. This study evaluated the cytotoxicity of nanosized HfO(2), SiO(2), Al(2)O(3) and CeO(2) towards the eukaryotic model organism Saccharomyces cerevisiae, and characterized their state of dispersion in bioassay medium. Nanotoxicity was assessed by monitoring oxygen consumption in batch cultures and by analysis of cell membrane integrity. CeO(2), Al(2)O(3), and HfO(2) nanoparticles were highly unstable in yeast medium and formed micron-sized, settleable agglomerates. A non-toxic polyacrylate dispersant (Dispex A40) was used to improve nanoparticle stability and determine the impact of enhanced dispersion on toxicity. None of the NPs tested without dispersant inhibited O(2) uptake by yeast at concentrations as high as 1000 mg/L. Dispersant supplementation only enhanced the toxicity of CeO(2) (47% at 1000 mg/L). Dispersed SiO(2) and Al(2)O(3) (1000 mg/L) caused cell membrane damage, whereas dispersed HfO(2) and CeO(2) did not cause significant disruption of membrane integrity at the same concentration. These results suggest that the O(2) uptake inhibition observed with dispersed CeO(2) NPs was not due to reduced cell viability. This is the first study evaluating toxicity of nanoscale HfO(2), SiO(2), Al(2)O(3) and CeO(2) to S. cerevisiae. Overall the results obtained demonstrate that these nanomaterials display low or no toxicity to yeast. Copyright © 2011 Elsevier B.V. All rights reserved.

Quantifying entanglement in two-mode Gaussian states

NASA Astrophysics Data System (ADS)

Tserkis, Spyros; Ralph, Timothy C.

2017-12-01

Entangled two-mode Gaussian states are a key resource for quantum information technologies such as teleportation, quantum cryptography, and quantum computation, so quantification of Gaussian entanglement is an important problem. Entanglement of formation is unanimously considered a proper measure of quantum correlations, but for arbitrary two-mode Gaussian states no analytical form is currently known. In contrast, logarithmic negativity is a measure that is straightforward to calculate and so has been adopted by most researchers, even though it is a less faithful quantifier. In this work, we derive an analytical lower bound for entanglement of formation of generic two-mode Gaussian states, which becomes tight for symmetric states and for states with balanced correlations. We define simple expressions for entanglement of formation in physically relevant situations and use these to illustrate the problematic behavior of logarithmic negativity, which can lead to spurious conclusions.

Remembering Apple CEO Steve Jobs as a "Transformational Leader": Implications for Pedagogy

ERIC Educational Resources Information Center

Steinwart, Marlane C.; Ziegler, Jennifer A.

2014-01-01

This paper explores the implications of using Apple co-founder and former CEO Steve Jobs as a "paradigm case" of transformational leadership by comparing the practical metadiscourse of remembrances published at the time of his passing to the theoretical metadiscourse of transformational leadership. The authors report the frequency of…

Mode entanglement of Gaussian fermionic states

NASA Astrophysics Data System (ADS)

Spee, C.; Schwaiger, K.; Giedke, G.; Kraus, B.

2018-04-01

We investigate the entanglement of n -mode n -partite Gaussian fermionic states (GFS). First, we identify a reasonable definition of separability for GFS and derive a standard form for mixed states, to which any state can be mapped via Gaussian local unitaries (GLU). As the standard form is unique, two GFS are equivalent under GLU if and only if their standard forms coincide. Then, we investigate the important class of local operations assisted by classical communication (LOCC). These are central in entanglement theory as they allow one to partially order the entanglement contained in states. We show, however, that there are no nontrivial Gaussian LOCC (GLOCC) among pure n -partite (fully entangled) states. That is, any such GLOCC transformation can also be accomplished via GLU. To obtain further insight into the entanglement properties of such GFS, we investigate the richer class of Gaussian stochastic local operations assisted by classical communication (SLOCC). We characterize Gaussian SLOCC classes of pure n -mode n -partite states and derive them explicitly for few-mode states. Furthermore, we consider certain fermionic LOCC and show how to identify the maximally entangled set of pure n -mode n -partite GFS, i.e., the minimal set of states having the property that any other state can be obtained from one state inside this set via fermionic LOCC. We generalize these findings also to the pure m -mode n -partite (for m >n ) case.

Gaussian Mixture Model of Heart Rate Variability

PubMed Central

Costa, Tommaso; Boccignone, Giuseppe; Ferraro, Mario

2012-01-01

Heart rate variability (HRV) is an important measure of sympathetic and parasympathetic functions of the autonomic nervous system and a key indicator of cardiovascular condition. This paper proposes a novel method to investigate HRV, namely by modelling it as a linear combination of Gaussians. Results show that three Gaussians are enough to describe the stationary statistics of heart variability and to provide a straightforward interpretation of the HRV power spectrum. Comparisons have been made also with synthetic data generated from different physiologically based models showing the plausibility of the Gaussian mixture parameters. PMID:22666386

On Gaussian feedback capacity

NASA Technical Reports Server (NTRS)

Dembo, Amir

1989-01-01

Pinsker and Ebert (1970) proved that in channels with additive Gaussian noise, feedback at most doubles the capacity. Cover and Pombra (1989) proved that feedback at most adds half a bit per transmission. Following their approach, the author proves that in the limit as signal power approaches either zero (very low SNR) or infinity (very high SNR), feedback does not increase the finite block-length capacity (which for nonstationary Gaussian channels replaces the standard notion of capacity that may not exist). Tighter upper bounds on the capacity are obtained in the process. Specializing these results to stationary channels, the author recovers some of the bounds recently obtained by Ozarow.

Structure and photoluminescence studies of CeO2·CuAlO2 mixed metal oxide fabricated by co-precipitation method.

PubMed

Subhan, Md Abdus; Ahmed, Tanzir; Awal, M R; Kim, B Moon

2015-01-25

A novel mixed metal oxide, CeO2·CuAlO2 was fabricated by co-precipitation method in aqueous medium. CeO2·CuAlO2 was characterized by XRD, SEM, EDS, TEM, FTIR and PL spectra. The optical properties of the nanoparticles were studied by photoluminescence (PL) spectra. PL spectra at different excitations were recorded. The composite showed emission in UV, visible and NIR region depending on the excitation wavelength. The special spectral feature observed for this composite is that it showed six emission bands at 364, 409, 434, 448, 465 and 481 nm when excited at 298 nm. The green and red emissions observed at 512 and 669 nm are originated from cubic CeO2 phase when excited at 450 nm. The PL spectra were found to be dependent on excitation wavelength violating Kasha's rule. The X-ray diffraction reveals a cubic CeO2 phase and hexagonal CuAlO2 phase. EDS spectra revealed the presence of cerium (Ce), copper (Cu), aluminum (Al) and oxygen (O) elements. The particle size of the CeO2·CuAlO2 mixed oxide was estimated using Scherrer's formula, which was found to be in the range of 17.2-34.2 nm. The TEM image showed particles are almost uniform size of approximately 15-50 nm with spherical morphology. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of CeO2 on Microstructure and Wear Resistance of TiC Bioinert Coatings on Ti6Al4V Alloy by Laser Cladding

PubMed Central

Wang, Haojun

2017-01-01

To solve the lack of wear resistance of titanium alloys for use in biological applications, various prepared coatings on titanium alloys are often used as wear-resistant materials. In this paper, TiC bioinert coatings were fabricated on Ti6Al4V by laser cladding using mixed TiC and ZrO2 powders as the basic pre-placed materials. A certain amount of CeO2 powder was also added to the pre-placed powders to further improve the properties of the TiC coatings. The effects of CeO2 additive on the phase constituents, microstructures and wear resistance of the TiC coatings were researched in detail. Although the effect of CeO2 on the phase constituents of the coatings was slight, it had a significant effect on the microstructure and wear resistance of the coatings. The crystalline grains in the TiC coatings, observed by a scanning electron microscope (SEM), were refined due to the effect of the CeO2. With the increase of CeO2 additive content in the pre-placed powders, finer and more compact dendrites led to improvement of the micro-hardness and wear resistance of the TiC coatings. Also, 5 wt % content of CeO2 additive in the pre-placed powders was the best choice for improving the wear properties of the TiC coatings. PMID:29301218

Comparison of the effects of platinum and CeO2 on the properties of single grain, Sm-Ba-Cu-O bulk superconductors

NASA Astrophysics Data System (ADS)

Zhao, Wen; Shi, Yunhua; Radušovská, Monika; Dennis, Anthony R.; Durrell, John H.; Diko, Pavel; Cardwell, David A.

2016-12-01

SmBa2Cu3O7-δ (Sm-123) is a light-rare-earth barium-cuprate (LRE-BCO) high-temperature superconductor (HTS) with significant potential for high field industrial applications. We report the fabrication of large, single grain bulk [Sm-Ba-Cu-O (SmBCO)] superconductors containing 1 wt% CeO2 and 0.1 wt% Pt using a top-seeded melt growth process. The performance of the SmBCO bulk superconductors containing the different dopants was evaluated based on an analysis of their superconducting properties, including critical transition temperature, T c and critical current density, J c , and on sample microstructure. We find that both CeO2 and Pt dopants refine the size of Sm2BaCuO5 (Sm-211) particles trapped in the Sm-123 superconducting phase matrix, which act as effective flux pinning centres, although the addition of CeO2 results in broadly improved superconducting performance of the fully processed bulk single grain. However, 1 wt% CeO2 is significantly cheaper than 0.1 wt% Pt, which has clear economic benefits for use in medium to large scale production processes for these technologically important materials. Finally, the use of CeO2 results generally in the formation of finer Sm-211 particles and to the generation of fewer macro-cracks and Sm-211 free regions in the sample microstructure.

Recovering dark-matter clustering from galaxies with Gaussianization

NASA Astrophysics Data System (ADS)

McCullagh, Nuala; Neyrinck, Mark; Norberg, Peder; Cole, Shaun

2016-04-01

The Gaussianization transform has been proposed as a method to remove the issues of scale-dependent galaxy bias and non-linearity from galaxy clustering statistics, but these benefits have yet to be thoroughly tested for realistic galaxy samples. In this paper, we test the effectiveness of the Gaussianization transform for different galaxy types by applying it to realistic simulated blue and red galaxy samples. We show that in real space, the shapes of the Gaussianized power spectra of both red and blue galaxies agree with that of the underlying dark matter, with the initial power spectrum, and with each other to smaller scales than do the statistics of the usual (untransformed) density field. However, we find that the agreement in the Gaussianized statistics breaks down in redshift space. We attribute this to the fact that red and blue galaxies exhibit very different fingers of god in redshift space. After applying a finger-of-god compression, the agreement on small scales between the Gaussianized power spectra is restored. We also compare the Gaussianization transform to the clipped galaxy density field and find that while both methods are effective in real space, they have more complicated behaviour in redshift space. Overall, we find that Gaussianization can be useful in recovering the shape of the underlying dark-matter power spectrum to k ˜ 0.5 h Mpc-1 and of the initial power spectrum to k ˜ 0.4 h Mpc-1 in certain cases at z = 0.

Gaussian discriminating strength

NASA Astrophysics Data System (ADS)

Rigovacca, L.; Farace, A.; De Pasquale, A.; Giovannetti, V.

2015-10-01

We present a quantifier of nonclassical correlations for bipartite, multimode Gaussian states. It is derived from the Discriminating Strength measure, introduced for finite dimensional systems in Farace et al., [New J. Phys. 16, 073010 (2014), 10.1088/1367-2630/16/7/073010]. As the latter the new measure exploits the quantum Chernoff bound to gauge the susceptibility of the composite system with respect to local perturbations induced by unitary gates extracted from a suitable set of allowed transformations (the latter being identified by posing some general requirements). Closed expressions are provided for the case of two-mode Gaussian states obtained by squeezing or by linearly mixing via a beam splitter a factorized two-mode thermal state. For these density matrices, we study how nonclassical correlations are related with the entanglement present in the system and with its total photon number.

In-situ IR spectroscopy as a probe of oxidation/reduction of Ce in nanostructured CeO2

NASA Astrophysics Data System (ADS)

Wu, Weiqiang; Savereide, Louisa Marie; Notestein, Justin; Weitz, Eric

2018-07-01

The redox properties of CeO2 are crucial in its applications in a wide range of catalytic processes. In the present research, in-situ IR spectroscopy is shown to be a viable and convenient method for the characterization of the oxidation state of Ce by monitoring the spin-orbit transition in Ce3+ (2F5/2 → 2F7/2) at ∼2147 cm-1. By monitoring this transition in CeO2 nanorods, the apparent activation energy for the production of oxygen vacancies that accompany the formation of Ce3+ has been determined and is shown to be lower for reduction with cyclohexene than with hydrogen. The bi-exponential kinetics for the formation of oxygen vacancies in CeO2 nanorods is discussed. An application of this method to real time monitoring of the oxidation state of Ce in the oxidation of cyclohexene on vanadia supported on ceria is presented as an example of how this method can be used as an operando probe of reaction mechanisms.

Using Linear and Quadratic Functions to Teach Number Patterns in Secondary School

ERIC Educational Resources Information Center

Kenan, Kok Xiao-Feng

2017-01-01

This paper outlines an approach to definitively find the general term in a number pattern, of either a linear or quadratic form, by using the general equation of a linear or quadratic function. This approach is governed by four principles: (1) identifying the position of the term (input) and the term itself (output); (2) recognising that each…

Back to Normal! Gaussianizing posterior distributions for cosmological probes

NASA Astrophysics Data System (ADS)

Schuhmann, Robert L.; Joachimi, Benjamin; Peiris, Hiranya V.

2014-05-01

We present a method to map multivariate non-Gaussian posterior probability densities into Gaussian ones via nonlinear Box-Cox transformations, and generalizations thereof. This is analogous to the search for normal parameters in the CMB, but can in principle be applied to any probability density that is continuous and unimodal. The search for the optimally Gaussianizing transformation amongst the Box-Cox family is performed via a maximum likelihood formalism. We can judge the quality of the found transformation a posteriori: qualitatively via statistical tests of Gaussianity, and more illustratively by how well it reproduces the credible regions. The method permits an analytical reconstruction of the posterior from a sample, e.g. a Markov chain, and simplifies the subsequent joint analysis with other experiments. Furthermore, it permits the characterization of a non-Gaussian posterior in a compact and efficient way. The expression for the non-Gaussian posterior can be employed to find analytic formulae for the Bayesian evidence, and consequently be used for model comparison.

Superstatistical generalised Langevin equation: non-Gaussian viscoelastic anomalous diffusion

NASA Astrophysics Data System (ADS)

Ślęzak, Jakub; Metzler, Ralf; Magdziarz, Marcin

2018-02-01

Recent advances in single particle tracking and supercomputing techniques demonstrate the emergence of normal or anomalous, viscoelastic diffusion in conjunction with non-Gaussian distributions in soft, biological, and active matter systems. We here formulate a stochastic model based on a generalised Langevin equation in which non-Gaussian shapes of the probability density function and normal or anomalous diffusion have a common origin, namely a random parametrisation of the stochastic force. We perform a detailed analysis demonstrating how various types of parameter distributions for the memory kernel result in exponential, power law, or power-log law tails of the memory functions. The studied system is also shown to exhibit a further unusual property: the velocity has a Gaussian one point probability density but non-Gaussian joint distributions. This behaviour is reflected in the relaxation from a Gaussian to a non-Gaussian distribution observed for the position variable. We show that our theoretical results are in excellent agreement with stochastic simulations.

Capacity of PPM on Gaussian and Webb Channels

NASA Technical Reports Server (NTRS)

Divsalar, D.; Dolinar, S.; Pollara, F.; Hamkins, J.

2000-01-01

This paper computes and compares the capacities of M-ary PPM on various idealized channels that approximate the optical communication channel: (1) the standard additive white Gaussian noise (AWGN) channel;(2) a more general AWGN channel (AWGN2) allowing different variances in signal and noise slots;(3) a Webb-distributed channel (Webb2);(4) a Webb+Gaussian channel, modeling Gaussian thermal noise added to Webb-distributed channel outputs.

Linear-quadratic-Gaussian synthesis with reduced parameter sensitivity

NASA Technical Reports Server (NTRS)

Lin, J. Y.; Mingori, D. L.

1992-01-01

We present a method for improving the tolerance of a conventional LQG controller to parameter errors in the plant model. The improvement is achieved by introducing additional terms reflecting the structure of the parameter errors into the LQR cost function, and also the process and measurement noise models. Adjusting the sizes of these additional terms permits a trade-off between robustness and nominal performance. Manipulation of some of the additional terms leads to high gain controllers while other terms lead to low gain controllers. Conditions are developed under which the high-gain approach asymptotically recovers the robustness of the corresponding full-state feedback design, and the low-gain approach makes the closed-loop poles asymptotically insensitive to parameter errors.

Reactivity and reaction intermediates for acetic acid adsorbed on CeO 2(111)

DOE PAGES

Calaza, Florencia C.; Chen, Tsung -Liang; Mullins, David R.; ...

2015-05-02

Adsorption and reaction of acetic acid on a CeO 2(1 1 1) surface was studied by a combination of ultra-highvacuum based methods including temperature desorption spectroscopy (TPD), soft X-ray photoelectronspectroscopy (sXPS), near edge X-ray absorption spectroscopy (NEXAFS) and reflection absorption IRspectroscopy (RAIRS), together with density functional theory (DFT) calculations. TPD shows that thedesorption products are strongly dependent upon the initial oxidation state of the CeO 2 surface, includingselectivity between acetone and acetaldehyde products. The combination of sXPS and NEXAFS demon-strate that acetate forms upon adsorption at low temperature and is stable to above 500 K, above whichpoint ketene, acetone andmore » acetic acid desorb. Furthermore, DFT and RAIRS show that below 500 K, bridge bondedacetate coexists with a moiety formed by adsorption of an acetate at an oxygen vacancy, formed bywater desorption.« less

Multipartite Gaussian steering: Monogamy constraints and quantum cryptography applications

NASA Astrophysics Data System (ADS)

Xiang, Yu; Kogias, Ioannis; Adesso, Gerardo; He, Qiongyi

2017-01-01

We derive laws for the distribution of quantum steering among different parties in multipartite Gaussian states under Gaussian measurements. We prove that a monogamy relation akin to the generalized Coffman-Kundu-Wootters inequality holds quantitatively for a recently introduced measure of Gaussian steering. We then define the residual Gaussian steering, stemming from the monogamy inequality, as an indicator of collective steering-type correlations. For pure three-mode Gaussian states, the residual acts as a quantifier of genuine multipartite steering, and is interpreted operationally in terms of the guaranteed key rate in the task of secure quantum secret sharing. Optimal resource states for the latter protocol are identified, and their possible experimental implementation discussed. Our results pin down the role of multipartite steering for quantum communication.

Exponential Thurston maps and limits of quadratic differentials

NASA Astrophysics Data System (ADS)

Hubbard, John; Schleicher, Dierk; Shishikura, Mitsuhiro

2009-01-01

We give a topological characterization of postsingularly finite topological exponential maps, i.e., universal covers g\\colon{C}to{C}setminus\\{0\\} such that 0 has a finite orbit. Such a map either is Thurston equivalent to a unique holomorphic exponential map λ e^z or it has a topological obstruction called a degenerate Levy cycle. This is the first analog of Thurston's topological characterization theorem of rational maps, as published by Douady and Hubbard, for the case of infinite degree. One main tool is a theorem about the distribution of mass of an integrable quadratic differential with a given number of poles, providing an almost compact space of models for the entire mass of quadratic differentials. This theorem is given for arbitrary Riemann surfaces of finite type in a uniform way.

Analysis of Flow and Transport in non-Gaussian Heterogeneous Formations Using a Generalized Sub-Gaussian Model

NASA Astrophysics Data System (ADS)

Guadagnini, A.; Riva, M.; Neuman, S. P.

2016-12-01

Environmental quantities such as log hydraulic conductivity (or transmissivity), Y(x) = ln K(x), and their spatial (or temporal) increments, ΔY, are known to be generally non-Gaussian. Documented evidence of such behavior includes symmetry of increment distributions at all separation scales (or lags) between incremental values of Y with sharp peaks and heavy tails that decay asymptotically as lag increases. This statistical scaling occurs in porous as well as fractured media characterized by either one or a hierarchy of spatial correlation scales. In hierarchical media one observes a range of additional statistical ΔY scaling phenomena, all of which are captured comprehensibly by a novel generalized sub-Gaussian (GSG) model. In this model Y forms a mixture Y(x) = U(x) G(x) of single- or multi-scale Gaussian processes G having random variances, U being a non-negative subordinator independent of G. Elsewhere we developed ways to generate unconditional and conditional random realizations of isotropic or anisotropic GSG fields which can be embedded in numerical Monte Carlo flow and transport simulations. Here we present and discuss expressions for probability distribution functions of Y and ΔY as well as their lead statistical moments. We then focus on a simple flow setting of mean uniform steady state flow in an unbounded, two-dimensional domain, exploring ways in which non-Gaussian heterogeneity affects stochastic flow and transport descriptions. Our expressions represent (a) lead order autocovariance and cross-covariance functions of hydraulic head, velocity and advective particle displacement as well as (b) analogues of preasymptotic and asymptotic Fickian dispersion coefficients. We compare them with corresponding expressions developed in the literature for Gaussian Y.

How Gaussian can our Universe be?

NASA Astrophysics Data System (ADS)

Cabass, G.; Pajer, E.; Schmidt, F.

2017-01-01

Gravity is a non-linear theory, and hence, barring cancellations, the initial super-horizon perturbations produced by inflation must contain some minimum amount of mode coupling, or primordial non-Gaussianity. In single-field slow-roll models, where this lower bound is saturated, non-Gaussianity is controlled by two observables: the tensor-to-scalar ratio, which is uncertain by more than fifty orders of magnitude; and the scalar spectral index, or tilt, which is relatively well measured. It is well known that to leading and next-to-leading order in derivatives, the contributions proportional to the tilt disappear from any local observable, and suspicion has been raised that this might happen to all orders, allowing for an arbitrarily low amount of primordial non-Gaussianity. Employing Conformal Fermi Coordinates, we show explicitly that this is not the case. Instead, a contribution of order the tilt appears in local observables. In summary, the floor of physical primordial non-Gaussianity in our Universe has a squeezed-limit scaling of kl2/ks2, similar to equilateral and orthogonal shapes, and a dimensionless amplitude of order 0.1 × (ns-1).

Balancing incentives in the compensation contracts of nonprofit hospital CEOs.

PubMed

Preyra, C; Pink, G

2001-07-01

Given the considerable insight into corporate governance achieved through studies of executive compensation in proprietary firms it is surprising that executive contracting in nonprofit organizations remains largely unexplored. In this paper, we use the multitask principal agent model of Holmström and Milgrom [The Journal of Law, Economics and Organization 7 (1991) (Suppl.) 24] to argue that nonprofit hospitals represent an optimal response to information asymmetries between managers and boards. For a board with multidimensional objectives, the agency problem is getting top executives to distribute their efforts across all dimensions of the hospital's mission. The nonprofit form is preferred because the absence of high powered incentives such as share ownership reduces executives' incentives to place undue emphasis on improving financial performance at the expense of important but less observable tasks. Using newly available compensation data we test the model by comparing the conditional distributions of earnings for industrial and nonprofit hospital CEOs in Ontario. Our best estimates are that CEOs in publicly traded firms earn twice as much on average as those in similarly sized nonprofit hospitals but bear roughly eight times the income variance. Estimates of the associated degree of risk aversion are well within conventional bounds and are consistent with the trade-off between insurance and incentives predicted by the theory.

Aerosol Physics Considerations for Using Cerium Oxide CeO 2 as a Surrogate for Plutonium Oxide PuO 2 in Airborne Release Fraction Measurements for Storage Container Investigations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, Murray E.; Tao, Yong

Cerium oxide (CeO2) dust is recommended as a surrogate for plutonium oxide (PuO2) in airborne release fraction experiments. The total range of applicable particle sizes for PuO2 extends from 0.0032 μm (the diameter of a single PuO2 molecule) to 10 μm (the defined upper boundary for respirable particles). For particulates with a physical particle diameter of 1.0 μm, the corresponding aerodynamic diameters for CeO2 and PuO2 are 2.7 μm and 3.4 μm, respectively. Cascade impactor air samplers are capable of measuring the size distributions of CeO2 or PuO2 particulates. In this document, the aerodynamic diameters for CeO2 and PuO2 weremore » calculated for seven different physical diameters (0.0032, 0.02, 0.11, 0.27, 1.0, 3.2, and 10 μm). For cascade impactor measurements, CeO2 and PuO2 particulates with the same physical diameter would be collected onto the same or adjacent collection substrates. The difference between the aerodynamic diameter of CeO2 and PuO2 particles (that have the same physical diameter) is 39% of the resolution of a twelve-stage MSP Inc. 125 cascade impactor, and 34% for an eight-stage Andersen impactor. An approach is given to calculate the committed effective dose (CED) coefficient for PuO2 aerosol particles, compared to a corresponding aerodynamic diameter of CeO2 particles. With this approach, use of CeO2 as a surrogate for PuO2 material would follow a direct conversion based on a molar equivalent. In addition to the analytical information developed for this document, several US national labs have published articles about the use of CeO2 as a PuO2 surrogate. Different physical and chemical aspects were considered by these investigators, including thermal properties, ceramic formulations, cold pressing, sintering, molecular reactions, and mass loss in high temperature gas flows. All of those US national lab studies recommended the use of CeO2 as a surrogate material for PuO2.« less

Evaluation of non-Gaussian diffusion in cardiac MRI.

PubMed

McClymont, Darryl; Teh, Irvin; Carruth, Eric; Omens, Jeffrey; McCulloch, Andrew; Whittington, Hannah J; Kohl, Peter; Grau, Vicente; Schneider, Jürgen E

2017-09-01

The diffusion tensor model assumes Gaussian diffusion and is widely applied in cardiac diffusion MRI. However, diffusion in biological tissue deviates from a Gaussian profile as a result of hindrance and restriction from cell and tissue microstructure, and may be quantified better by non-Gaussian modeling. The aim of this study was to investigate non-Gaussian diffusion in healthy and hypertrophic hearts. Thirteen rat hearts (five healthy, four sham, four hypertrophic) were imaged ex vivo. Diffusion-weighted images were acquired at b-values up to 10,000 s/mm 2 . Models of diffusion were fit to the data and ranked based on the Akaike information criterion. The diffusion tensor was ranked best at b-values up to 2000 s/mm 2 but reflected the signal poorly in the high b-value regime, in which the best model was a non-Gaussian "beta distribution" model. Although there was considerable overlap in apparent diffusivities between the healthy, sham, and hypertrophic hearts, diffusion kurtosis and skewness in the hypertrophic hearts were more than 20% higher in the sheetlet and sheetlet-normal directions. Non-Gaussian diffusion models have a higher sensitivity for the detection of hypertrophy compared with the Gaussian model. In particular, diffusion kurtosis may serve as a useful biomarker for characterization of disease and remodeling in the heart. Magn Reson Med 78:1174-1186, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

AIHEC CEO Carrie Billy Explains What Drives Her as Public Servant, Mother

ERIC Educational Resources Information Center

Schilling, Vincent

2009-01-01

This article profiles American Indian Higher Education Consortium's (AIHEC) President and CEO Carrie Billy. Billy's experience in law, a U.S. senator's office, and in the legislative and administrative branches of government is crucial for an institution that relies on state and federal legislative processes to gain funding and support. AIHEC is a…

Primordial non-Gaussianity and reionization

NASA Astrophysics Data System (ADS)

Lidz, Adam; Baxter, Eric J.; Adshead, Peter; Dodelson, Scott

2013-07-01

The statistical properties of the primordial perturbations contain clues about their origins. Although the Planck collaboration has recently obtained tight constraints on primordial non-Gaussianity from cosmic microwave background measurements, it is still worthwhile to mine upcoming data sets in an effort to place independent or competitive limits. The ionized bubbles that formed at redshift z˜6-20 during the epoch of reionization were seeded by primordial overdensities, and so the statistics of the ionization field at high redshift are related to the statistics of the primordial field. Here we model the effect of primordial non-Gaussianity on the reionization field. The epoch and duration of reionization are affected, as are the sizes of the ionized bubbles, but these changes are degenerate with variations in the properties of the ionizing sources and the surrounding intergalactic medium. A more promising signature is the power spectrum of the spatial fluctuations in the ionization field, which may be probed by upcoming 21 cm surveys. This has the expected 1/k2 dependence on large scales, characteristic of a biased tracer of the matter field. We project how well upcoming 21 cm observations will be able to disentangle this signal from foreground contamination. Although foreground cleaning inevitably removes the large-scale modes most impacted by primordial non-Gaussianity, we find that primordial non-Gaussianity can be separated from foreground contamination for a narrow range of length scales. In principle, futuristic redshifted 21 cm surveys may allow constraints competitive with Planck.

Quadratic RK shooting solution for a environmental parameter prediction boundary value problem

NASA Astrophysics Data System (ADS)

Famelis, Ioannis Th.; Tsitouras, Ch.

2014-10-01

Using tools of Information Geometry, the minimum distance between two elements of a statistical manifold is defined by the corresponding geodesic, e.g. the minimum length curve that connects them. Such a curve, where the probability distribution functions in the case of our meteorological data are two parameter Weibull distributions, satisfies a 2nd order Boundary Value (BV) system. We study the numerical treatment of the resulting special quadratic form system using Shooting method. We compare the solutions of the problem when we employ a classical Singly Diagonally Implicit Runge Kutta (SDIRK) 4(3) pair of methods and a quadratic SDIRK 5(3) pair . Both pairs have the same computational costs whereas the second one attains higher order as it is specially constructed for quadratic problems.

The Classification for Early-onset Scoliosis (C-EOS) Correlates With the Speed of Vertical Expandable Prosthetic Titanium Rib (VEPTR) Proximal Anchor Failure.

PubMed

Park, Howard Y; Matsumoto, Hiroko; Feinberg, Nicholas; Roye, David P; Kanj, Wajdi W; Betz, Randal R; Cahill, Patrick J; Glotzbecker, Michael P; Luhmann, Scott J; Garg, Sumeet; Sawyer, Jeffrey R; Smith, John T; Flynn, John M; Vitale, Michael G

2017-09-01

The Classification for Early-onset Scoliosis (C-EOS) was developed by a consortium of early-onset scoliosis (EOS) surgeons. This study aims to examine if the C-EOS classification correlates with the speed (failure/unit time) of proximal anchor failure in EOS surgery patients. A total of 106 EOS patients were retrospectively queried from an EOS database. All patients were treated with vertical expandable prosthetic titanium rib and experienced proximal anchor failure. Patients were classified by the C-EOS, which includes a term for etiology [C: Congenital (54.2%), M: Neuromuscular (32.3%), S: Syndromic (8.3%), I: Idiopathic (5.2%)], major curve angle [1: ≤20 degrees (0%), 2: 21 to 50 degrees (15.6%), 3: 51 to 90 degrees (66.7%), 4: >90 degrees (17.7%)], and kyphosis ["-": ≤20 (13.5%), "N": 21 to 50 (42.7%), "+": >50 (43.8%)]. Outcome was measured by time and number of lengthenings to failure. Analyzing C-EOS classes with >3 subjects, survival analysis demonstrates that the C-EOS discriminates low, medium, and high speed of failure. The low speed of failure group consisted of congenital/51-90/hypokyphosis (C3-) class. The medium-speed group consisted of congenital/51-90/normal and hyperkyphosis (C3N, C3+), and neuromuscular/51-90/hyperkyphosis (M3+) classes. The high-speed group consisted of neuromuscular/51-90/normal kyphosis (M3N), and neuromuscular/>90/normal and hyperkyphosis (M4N, M4+) classes. Significant differences were found in time (P<0.05) and number of expansions (P<0.05) before failure between congenital and neuromuscular classes.As isolated variables, neuromuscular etiology experienced a significantly faster time to failure compared with patients with idiopathic (P<0.001) and congenital (P=0.026) etiology. Patients with a major curve angle >90 degrees demonstrated significantly faster speed of failure compared with patients with major curve angle 21 to 50 degrees (P=0.011). The ability of the C-EOS to discriminate the speeds of failure of the

Exact solutions for an oscillator with anti-symmetric quadratic nonlinearity

NASA Astrophysics Data System (ADS)

Beléndez, A.; Martínez, F. J.; Beléndez, T.; Pascual, C.; Alvarez, M. L.; Gimeno, E.; Arribas, E.

2018-04-01

Closed-form exact solutions for an oscillator with anti-symmetric quadratic nonlinearity are derived from the first integral of the nonlinear differential equation governing the behaviour of this oscillator. The mathematical model is an ordinary second order differential equation in which the sign of the quadratic nonlinear term changes. Two parameters characterize this oscillator: the coefficient of the linear term and the coefficient of the quadratic term. Not only the common case in which both coefficients are positive but also all possible combinations of positive and negative signs of these coefficients which provide periodic motions are considered, giving rise to four different cases. Three different periods and solutions are obtained, since the same result is valid in two of these cases. An interesting feature is that oscillatory motions whose equilibrium points are not at x = 0 are also considered. The periods are given in terms of an incomplete or complete elliptic integral of the first kind, and the exact solutions are expressed as functions including Jacobi elliptic cosine or sine functions.

Some error bounds for K-iterated Gaussian recursive filters

NASA Astrophysics Data System (ADS)

Cuomo, Salvatore; Galletti, Ardelio; Giunta, Giulio; Marcellino, Livia

2016-10-01

Recursive filters (RFs) have achieved a central role in several research fields over the last few years. For example, they are used in image processing, in data assimilation and in electrocardiogram denoising. More in particular, among RFs, the Gaussian RFs are an efficient computational tool for approximating Gaussian-based convolutions and are suitable for digital image processing and applications of the scale-space theory. As is a common knowledge, the Gaussian RFs, applied to signals with support in a finite domain, generate distortions and artifacts, mostly localized at the boundaries. Heuristic and theoretical improvements have been proposed in literature to deal with this issue (namely boundary conditions). They include the case in which a Gaussian RF is applied more than once, i.e. the so called K-iterated Gaussian RFs. In this paper, starting from a summary of the comprehensive mathematical background, we consider the case of the K-iterated first-order Gaussian RF and provide the study of its numerical stability and some component-wise theoretical error bounds.

Quadratic grating apodized photon sieves for simultaneous multiplane microscopy

NASA Astrophysics Data System (ADS)

Cheng, Yiguang; Zhu, Jiangping; He, Yu; Tang, Yan; Hu, Song; Zhao, Lixin

2017-10-01

We present a new type of imaging device, named quadratic grating apodized photon sieve (QGPS), used as the objective for simultaneous multiplane imaging in X-rays. The proposed QGPS is structured based on the combination of two concepts: photon sieves and quadratic gratings. Its design principles are also expounded in detail. Analysis of imaging properties of QGPS in terms of point-spread function shows that QGPS can image multiple layers within an object field onto a single image plane. Simulated and experimental results in visible light both demonstrate the feasibility of QGPS for simultaneous multiplane imaging, which is extremely promising to detect dynamic specimens by X-ray microscopy in the physical and life sciences.

Collaboration using open standards and open source software (examples of DIAS/CEOS Water Portal)

NASA Astrophysics Data System (ADS)

Miura, S.; Sekioka, S.; Kuroiwa, K.; Kudo, Y.

2015-12-01

The DIAS/CEOS Water Portal is a part of the DIAS (Data Integration and Analysis System, http://www.editoria.u-tokyo.ac.jp/projects/dias/?locale=en_US) systems for data distribution for users including, but not limited to, scientists, decision makers and officers like river administrators. One of the functions of this portal is to enable one-stop search and access variable water related data archived multiple data centers located all over the world. This portal itself does not store data. Instead, according to requests made by users on the web page, it retrieves data from distributed data centers on-the-fly and lets them download and see rendered images/plots. Our system mainly relies on the open source software GI-cat (http://essi-lab.eu/do/view/GIcat) and open standards such as OGC-CSW, Opensearch and OPeNDAP protocol to enable the above functions. Details on how it works will be introduced during the presentation. Although some data centers have unique meta data format and/or data search protocols, our portal's brokering function enables users to search across various data centers at one time. And this portal is also connected to other data brokering systems, including GEOSS DAB (Discovery and Access Broker). As a result, users can search over thousands of datasets, millions of files at one time. Users can access the DIAS/CEOS Water Portal system at http://waterportal.ceos.org/.

Structure, bonding, and catalytic activity of monodisperse, transition-metal-substituted CeO2 nanoparticles.

PubMed

Elias, Joseph S; Risch, Marcel; Giordano, Livia; Mansour, Azzam N; Shao-Horn, Yang

2014-12-10

We present a simple and generalizable synthetic route toward phase-pure, monodisperse transition-metal-substituted ceria nanoparticles (M0.1Ce0.9O2-x, M = Mn, Fe, Co, Ni, Cu). The solution-based pyrolysis of a series of heterobimetallic Schiff base complexes ensures a rigorous control of the size, morphology and composition of 3 nm M0.1Ce0.9O2-x crystallites for CO oxidation catalysis and other applications. X-ray absorption spectroscopy confirms the dispersion of aliovalent (M(3+) and M(2+)) transition metal ions into the ceria matrix without the formation of any bulk transition metal oxide phases, while steady-state CO oxidation catalysis reveals an order of magnitude increase in catalytic activity with copper substitution. Density functional calculations of model slabs of these compounds confirm the stabilization of M(3+) and M(2+) in the lattice of CeO2. These results highlight the role of the host CeO2 lattice in stabilizing high oxidation states of aliovalent transition metal dopants that ordinarily would be intractable, such as Cu(3+), as well as demonstrating a rational approach to catalyst design. The current work demonstrates, for the first time, a generalizable approach for the preparation of transition-metal-substituted CeO2 for a broad range of transition metals with unparalleled synthetic control and illustrates that Cu(3+) is implicated in the mechanism for CO oxidation on CuO-CeO2 catalysts.

Pressure-induced phase transitions and correlation between structure and superconductivity in iron-based superconductor Ce(O(0.84)F(0.16))FeAs.

PubMed

Zhao, Jinggeng; Liu, Haozhe; Ehm, Lars; Dong, Dawei; Chen, Zhiqiang; Liu, Qingqing; Hu, Wanzheng; Wang, Nanlin; Jin, Changqing

2013-07-15

High-pressure angle-dispersive X-ray diffraction experiments on iron-based superconductor Ce(O(0.84)F(0.16))FeAs were performed up to 54.9 GPa at room temperature. A tetragonal to tetragonal isostructural phase transition starts at about 13.9 GPa, and a new high-pressure phase has been found above 33.8 GPa. At pressures above 19.9 GPa, Ce(O(0.84)F(0.16))FeAs completely transforms to a high-pressure tetragonal phase, which remains in the same tetragonal structure with a larger a-axis and smaller c-axis than those of the low-pressure tetragonal phase. The structure analysis shows a discontinuity in the pressure dependences of the Fe-As and Ce-(O, F) bond distances, as well as the As-Fe-As and Ce-(O, F)-Ce bond angles in the transition region, which correlates with the change in T(c) of this compound upon compression. The isostructural phase transition in Ce(O(0.84)F(0.16))FeAs leads to a drastic drop in the superconducting transition temperature T(c) and restricts the superconductivity at low temperature. For the 1111-type iron-based superconductors, the structure evolution and following superconductivity changes under compression are related to the radius of lanthanide cations in the charge reservoir layer.

Investigating Students' Mathematical Difficulties with Quadratic Equations

ERIC Educational Resources Information Center

O'Connor, Bronwyn Reid; Norton, Stephen

2016-01-01

This paper examines the factors that hinder students' success in working with and understanding the mathematics of quadratic equations using a case study analysis of student error patterns. Twenty-five Year 11 students were administered a written test to examine their understanding of concepts and procedures associated with this topic. The…

Method for optimizing channelized quadratic observers for binary classification of large-dimensional image datasets

PubMed Central

Kupinski, M. K.; Clarkson, E.

2015-01-01

We present a new method for computing optimized channels for channelized quadratic observers (CQO) that is feasible for high-dimensional image data. The method for calculating channels is applicable in general and optimal for Gaussian distributed image data. Gradient-based algorithms for determining the channels are presented for five different information-based figures of merit (FOMs). Analytic solutions for the optimum channels for each of the five FOMs are derived for the case of equal mean data for both classes. The optimum channels for three of the FOMs under the equal mean condition are shown to be the same. This result is critical since some of the FOMs are much easier to compute. Implementing the CQO requires a set of channels and the first- and second-order statistics of channelized image data from both classes. The dimensionality reduction from M measurements to L channels is a critical advantage of CQO since estimating image statistics from channelized data requires smaller sample sizes and inverting a smaller covariance matrix is easier. In a simulation study we compare the performance of ideal and Hotelling observers to CQO. The optimal CQO channels are calculated using both eigenanalysis and a new gradient-based algorithm for maximizing Jeffrey's divergence (J). Optimal channel selection without eigenanalysis makes the J-CQO on large-dimensional image data feasible. PMID:26366764

Kurtosis, skewness, and non-Gaussian cosmological density perturbations

NASA Technical Reports Server (NTRS)

Luo, Xiaochun; Schramm, David N.

1993-01-01

Cosmological topological defects as well as some nonstandard inflation models can give rise to non-Gaussian density perturbations. Skewness and kurtosis are the third and fourth moments that measure the deviation of a distribution from a Gaussian. Measurement of these moments for the cosmological density field and for the microwave background temperature anisotropy can provide a test of the Gaussian nature of the primordial fluctuation spectrum. In the case of the density field, the importance of measuring the kurtosis is stressed since it will be preserved through the weakly nonlinear gravitational evolution epoch. Current constraints on skewness and kurtosis of primeval perturbations are obtained from the observed density contrast on small scales and from recent COBE observations of temperature anisotropies on large scales. It is also shown how, in principle, future microwave anisotropy experiments might be able to reveal the initial skewness and kurtosis. It is shown that present data argue that if the initial spectrum is adiabatic, then it is probably Gaussian, but non-Gaussian isocurvature fluctuations are still allowed, and these are what topological defects provide.

Structural, optical and magnetic investigation of Gd implanted CeO2 nanocrystals

NASA Astrophysics Data System (ADS)

Kaviyarasu, K.; Murmu, P. P.; Kennedy, J.; Thema, F. T.; Letsholathebe, Douglas; Kotsedi, L.; Maaza, M.

2017-10-01

Gadolinium implanted cerium oxide (Gd-CeO2) nanocomposites is an important candidate which have unique hexagonal structure and high K- dielectric constant. Gd-CeO2 nanoparticles were synthesized using hydrothermal method. X-ray diffraction (XRD) results showed that the peaks are consistent with pure phase cubic structure the XRD pattern also confirmed crystallinity and phase purity of the sample. Nanocrystals sizes were found to be up to 25 nm as revealed by XRD and SEM. It is suggested that Gd gives an affirmative effect on the ion influence behavior of Gd-CeO2. XRD patterns showed formation of new phases and SEM micrographs revealed hexagonal structure. Photoluminescence measurement (PL) reveals the systematic shift of the emission band towards lower wavelength thereby ascertaining the quantum confinement effect (QCE). The PL spectrum has wider broad peak ranging from 390 nm to 770 nm and a sharp one centered on at 451.30 nm which is in tune with Gd ions. In the Raman spectra showed intense band observed between 460 cm-1 and 470 cm-1 which is attributed to oxygen ions into CeO2. Room temperature ferromagnetism was observed in un-doped and Gd implanted and annealed CeO2 nanocrystals. In the recent studies, ceria based materials have been considered as one of the most promising electrolytes for reduced temperature SOFC (solid oxide fuel cell) system due to their high ionic conductivities allowing its use in stainless steel supported fuel cells. CeO2 having an optical bandgap 3.3 eV and n-type carrier density which make it a promising candidate for various technological application such as buffer layer on silicon on insulator devices.

Sequential design of discrete linear quadratic regulators via optimal root-locus techniques

NASA Technical Reports Server (NTRS)

Shieh, Leang S.; Yates, Robert E.; Ganesan, Sekar

1989-01-01

A sequential method employing classical root-locus techniques has been developed in order to determine the quadratic weighting matrices and discrete linear quadratic regulators of multivariable control systems. At each recursive step, an intermediate unity rank state-weighting matrix that contains some invariant eigenvectors of that open-loop matrix is assigned, and an intermediate characteristic equation of the closed-loop system containing the invariant eigenvalues is created.

Non-Gaussianity in a quasiclassical electronic circuit

NASA Astrophysics Data System (ADS)

Suzuki, Takafumi J.; Hayakawa, Hisao

2017-05-01

We study the non-Gaussian dynamics of a quasiclassical electronic circuit coupled to a mesoscopic conductor. Non-Gaussian noise accompanying the nonequilibrium transport through the conductor significantly modifies the stationary probability density function (PDF) of the flux in the dissipative circuit. We incorporate weak quantum fluctuation of the dissipative LC circuit with a stochastic method and evaluate the quantum correction of the stationary PDF. Furthermore, an inverse formula to infer the statistical properties of the non-Gaussian noise from the stationary PDF is derived in the classical-quantum crossover regime. The quantum correction is indispensable to correctly estimate the microscopic transfer events in the QPC with the quasiclassical inverse formula.

Quantum non-Gaussianity and quantification of nonclassicality

NASA Astrophysics Data System (ADS)

Kühn, B.; Vogel, W.

2018-05-01

The algebraic quantification of nonclassicality, which naturally arises from the quantum superposition principle, is related to properties of regular nonclassicality quasiprobabilities. The latter are obtained by non-Gaussian filtering of the Glauber-Sudarshan P function. They yield lower bounds for the degree of nonclassicality. We also derive bounds for convex combinations of Gaussian states for certifying quantum non-Gaussianity directly from the experimentally accessible nonclassicality quasiprobabilities. Other quantum-state representations, such as s -parametrized quasiprobabilities, insufficiently indicate or even fail to directly uncover detailed information on the properties of quantum states. As an example, our approach is applied to multi-photon-added squeezed vacuum states.

Axial acoustic radiation force on a sphere in Gaussian field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Rongrong; Liu, Xiaozhou, E-mail: xzliu@nju.edu.cn; Gong, Xiufen

2015-10-28

Based on the finite series method, the acoustical radiation force resulting from a Gaussian beam incident on a spherical object is investigated analytically. When the position of the particles deviating from the center of the beam, the Gaussian beam is expanded as a spherical function at the center of the particles and the expanded coefficients of the Gaussian beam is calculated. The analytical expression of the acoustic radiation force on spherical particles deviating from the Gaussian beam center is deduced. The acoustic radiation force affected by the acoustic frequency and the offset distance from the Gaussian beam center is investigated.more » Results have been presented for Gaussian beams with different wavelengths and it has been shown that the interaction of a Gaussian beam with a sphere can result in attractive axial force under specific operational conditions. Results indicate the capability of manipulating and separating spherical spheres based on their mechanical and acoustical properties, the results provided here may provide a theoretical basis for development of single-beam acoustical tweezers.« less

Structure of Nano-sized CeO 2 Materials: Combined Scattering and Spectroscopic Investigations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marchbank, Huw R.; Clark, Adam H.; Hyde, Timothy I.

Here, the nature of nano-sized ceria, CeO 2, systems were investigated using neutron and X-ray diffraction and X-ray absorption spectroscopy. Whilst both diffraction andtotal pair distribution functions (PDFs) revealed that in all the samples the occupancy of both Ce 4+ and O 2- are very close to the ideal stoichiometry, the analysis using reverse Monte Carlo technique revealedsignificant disorder around oxygen atoms in the nano sized ceria samples in comparison to the highly crystalline NIST standard.In addition, the analysis reveal that the main differences observed in the pair correlations from various X-ray and neutron diffraction techniques were attributed to themore » particle size of the CeO 2 prepared by the reported three methods. Furthermore, detailed analysis of the Ce L 3– and K-edge EXAFS data support this finding; in particular the decrease in higher shell coordination numbers with respect to the NIST standard, are attributed to differences in particle size.« less

Structure of Nano-sized CeO 2 Materials: Combined Scattering and Spectroscopic Investigations

DOE PAGES

Marchbank, Huw R.; Clark, Adam H.; Hyde, Timothy I.; ...

2016-08-29

Here, the nature of nano-sized ceria, CeO 2, systems were investigated using neutron and X-ray diffraction and X-ray absorption spectroscopy. Whilst both diffraction andtotal pair distribution functions (PDFs) revealed that in all the samples the occupancy of both Ce 4+ and O 2- are very close to the ideal stoichiometry, the analysis using reverse Monte Carlo technique revealedsignificant disorder around oxygen atoms in the nano sized ceria samples in comparison to the highly crystalline NIST standard.In addition, the analysis reveal that the main differences observed in the pair correlations from various X-ray and neutron diffraction techniques were attributed to themore » particle size of the CeO 2 prepared by the reported three methods. Furthermore, detailed analysis of the Ce L 3– and K-edge EXAFS data support this finding; in particular the decrease in higher shell coordination numbers with respect to the NIST standard, are attributed to differences in particle size.« less

Comparisons of non-Gaussian statistical models in DNA methylation analysis.

PubMed

Ma, Zhanyu; Teschendorff, Andrew E; Yu, Hong; Taghia, Jalil; Guo, Jun

2014-06-16

As a key regulatory mechanism of gene expression, DNA methylation patterns are widely altered in many complex genetic diseases, including cancer. DNA methylation is naturally quantified by bounded support data; therefore, it is non-Gaussian distributed. In order to capture such properties, we introduce some non-Gaussian statistical models to perform dimension reduction on DNA methylation data. Afterwards, non-Gaussian statistical model-based unsupervised clustering strategies are applied to cluster the data. Comparisons and analysis of different dimension reduction strategies and unsupervised clustering methods are presented. Experimental results show that the non-Gaussian statistical model-based methods are superior to the conventional Gaussian distribution-based method. They are meaningful tools for DNA methylation analysis. Moreover, among several non-Gaussian methods, the one that captures the bounded nature of DNA methylation data reveals the best clustering performance.

Comparisons of Non-Gaussian Statistical Models in DNA Methylation Analysis

PubMed Central

Ma, Zhanyu; Teschendorff, Andrew E.; Yu, Hong; Taghia, Jalil; Guo, Jun

2014-01-01

As a key regulatory mechanism of gene expression, DNA methylation patterns are widely altered in many complex genetic diseases, including cancer. DNA methylation is naturally quantified by bounded support data; therefore, it is non-Gaussian distributed. In order to capture such properties, we introduce some non-Gaussian statistical models to perform dimension reduction on DNA methylation data. Afterwards, non-Gaussian statistical model-based unsupervised clustering strategies are applied to cluster the data. Comparisons and analysis of different dimension reduction strategies and unsupervised clustering methods are presented. Experimental results show that the non-Gaussian statistical model-based methods are superior to the conventional Gaussian distribution-based method. They are meaningful tools for DNA methylation analysis. Moreover, among several non-Gaussian methods, the one that captures the bounded nature of DNA methylation data reveals the best clustering performance. PMID:24937687

CEOS Contributions to Informing Energy Management and Policy Decision Making Using Space-Based Earth Observations

NASA Technical Reports Server (NTRS)

Eckman, Richard S.

2009-01-01

Earth observations are playing an increasingly significant role in informing decision making in the energy sector. In renewable energy applications, space-based observations now routinely augment sparse ground-based observations used as input for renewable energy resource assessment applications. As one of the nine Group on Earth Observations (GEO) societal benefit areas, the enhancement of management and policy decision making in the energy sector is receiving attention in activities conducted by the Committee on Earth Observation Satellites (CEOS). CEOS has become the "space arm" for the implementation of the Global Earth Observation System of Systems (GEOSS) vision. It is directly supporting the space-based, near-term tasks articulated in the GEO three-year work plan. This paper describes a coordinated program of demonstration projects conducted by CEOS member agencies and partners to utilize Earth observations to enhance energy management end-user decision support systems. I discuss the importance of engagement with stakeholders and understanding their decision support needs in successfully increasing the uptake of Earth observation products for societal benefit. Several case studies are presented, demonstrating the importance of providing data sets in formats and units familiar and immediately usable by decision makers. These projects show the utility of Earth observations to enhance renewable energy resource assessment in the developing world, forecast space-weather impacts on the power grid, and improve energy efficiency in the built environment.

Factorization method of quadratic template

NASA Astrophysics Data System (ADS)

Kotyrba, Martin

2017-07-01

Multiplication of two numbers is a one-way function in mathematics. Any attempt to distribute the outcome to its roots is called factorization. There are many methods such as Fermat's factorization, Dixońs method or quadratic sieve and GNFS, which use sophisticated techniques fast factorization. All the above methods use the same basic formula differing only in its use. This article discusses a newly designed factorization method. Effective implementation of this method in programs is not important, it only represents and clearly defines its properties.

Furious passion confronts the cool logic behind a CEO's hospital appointment

PubMed Central

Gray, C

1998-01-01

First, Ontario decided it would close or reduce the operations of 3 Ottawa hospitals and combine 2 others. When the board for the combined hospital named a Parti Québécois confidant the new hospital's CEO, it hoped David Levine's background would go unnoticed. As Charlotte Gray reports, it didn't, and Levine became the lightning rod for a lot of anger. PMID:9676554

Furious passion confronts the cool logic behind a CEO's hospital appointment.

PubMed

Gray, C

1998-06-30

First, Ontario decided it would close or reduce the operations of 3 Ottawa hospitals and combine 2 others. When the board for the combined hospital named a Parti Québécois confidant the new hospital's CEO, it hoped David Levine's background would go unnoticed. As Charlotte Gray reports, it didn't, and Levine became the lightning rod for a lot of anger.

CEOS Land Surface Imaging Constellation Mid-Resolution Optical Guidelines

NASA Technical Reports Server (NTRS)

Keyes, Jennifer P.; Killough, B.

2011-01-01

The LSI community of users is large and varied. To reach all these users as well as potential instrument contributors this document has been organized by measurement parameters of interest such as Leaf Area Index and Land Surface Temperature. These measurement parameters and the data presented in this document are drawn from multiple sources, listed at the end of the document, although the two primary ones are "The Space-Based Global Observing System in 2010 (GOS-2010)" that was compiled for the World Meteorological Organization (WMO) by Bizzarro Bizzarri, and the CEOS Missions, Instruments, and Measurements online database (CEOS MIM). For each measurement parameter the following topics will be discussed: (1) measurement description, (2) applications, (3) measurement spectral bands, and (4) example instruments and mission information. The description of each measurement parameter starts with a definition and includes a graphic displaying the relationships to four general land surface imaging user communities: vegetation, water, earth, and geo-hazards, since the LSI community of users is large and varied. The vegetation community uses LSI data to assess factors related to topics such as agriculture, forest management, crop type, chlorophyll, vegetation land cover, and leaf or canopy differences. The water community analyzes snow and lake cover, water properties such as clarity, and body of water delineation. The earth community focuses on minerals, soils, and sediments. The geo-hazards community is designed to address and aid in emergencies such as volcanic eruptions, forest fires, and large-scale damaging weather-related events.

Analysis of randomly time varying systems by gaussian closure technique

NASA Astrophysics Data System (ADS)

Dash, P. K.; Iyengar, R. N.

1982-07-01

The Gaussian probability closure technique is applied to study the random response of multidegree of freedom stochastically time varying systems under non-Gaussian excitations. Under the assumption that the response, the coefficient and the excitation processes are jointly Gaussian, deterministic equations are derived for the first two response moments. It is further shown that this technique leads to the best Gaussian estimate in a minimum mean square error sense. An example problem is solved which demonstrates the capability of this technique for handling non-linearity, stochastic system parameters and amplitude limited responses in a unified manner. Numerical results obtained through the Gaussian closure technique compare well with the exact solutions.

Diffusion weighted imaging in patients with rectal cancer: Comparison between Gaussian and non-Gaussian models

PubMed Central

Marias, Kostas; Lambregts, Doenja M. J.; Nikiforaki, Katerina; van Heeswijk, Miriam M.; Bakers, Frans C. H.; Beets-Tan, Regina G. H.

2017-01-01

Purpose The purpose of this study was to compare the performance of four diffusion models, including mono and bi-exponential both Gaussian and non-Gaussian models, in diffusion weighted imaging of rectal cancer. Material and methods Nineteen patients with rectal adenocarcinoma underwent MRI examination of the rectum before chemoradiation therapy including a 7 b-value diffusion sequence (0, 25, 50, 100, 500, 1000 and 2000 s/mm2) at a 1.5T scanner. Four different diffusion models including mono- and bi-exponential Gaussian (MG and BG) and non-Gaussian (MNG and BNG) were applied on whole tumor volumes of interest. Two different statistical criteria were recruited to assess their fitting performance, including the adjusted-R2 and Root Mean Square Error (RMSE). To decide which model better characterizes rectal cancer, model selection was relied on Akaike Information Criteria (AIC) and F-ratio. Results All candidate models achieved a good fitting performance with the two most complex models, the BG and the BNG, exhibiting the best fitting performance. However, both criteria for model selection indicated that the MG model performed better than any other model. In particular, using AIC Weights and F-ratio, the pixel-based analysis demonstrated that tumor areas better described by the simplest MG model in an average area of 53% and 33%, respectively. Non-Gaussian behavior was illustrated in an average area of 37% according to the F-ratio, and 7% using AIC Weights. However, the distributions of the pixels best fitted by each of the four models suggest that MG failed to perform better than any other model in all patients, and the overall tumor area. Conclusion No single diffusion model evaluated herein could accurately describe rectal tumours. These findings probably can be explained on the basis of increased tumour heterogeneity, where areas with high vascularity could be fitted better with bi-exponential models, and areas with necrosis would mostly follow mono

Diffusion weighted imaging in patients with rectal cancer: Comparison between Gaussian and non-Gaussian models.

PubMed

Manikis, Georgios C; Marias, Kostas; Lambregts, Doenja M J; Nikiforaki, Katerina; van Heeswijk, Miriam M; Bakers, Frans C H; Beets-Tan, Regina G H; Papanikolaou, Nikolaos

2017-01-01

The purpose of this study was to compare the performance of four diffusion models, including mono and bi-exponential both Gaussian and non-Gaussian models, in diffusion weighted imaging of rectal cancer. Nineteen patients with rectal adenocarcinoma underwent MRI examination of the rectum before chemoradiation therapy including a 7 b-value diffusion sequence (0, 25, 50, 100, 500, 1000 and 2000 s/mm2) at a 1.5T scanner. Four different diffusion models including mono- and bi-exponential Gaussian (MG and BG) and non-Gaussian (MNG and BNG) were applied on whole tumor volumes of interest. Two different statistical criteria were recruited to assess their fitting performance, including the adjusted-R2 and Root Mean Square Error (RMSE). To decide which model better characterizes rectal cancer, model selection was relied on Akaike Information Criteria (AIC) and F-ratio. All candidate models achieved a good fitting performance with the two most complex models, the BG and the BNG, exhibiting the best fitting performance. However, both criteria for model selection indicated that the MG model performed better than any other model. In particular, using AIC Weights and F-ratio, the pixel-based analysis demonstrated that tumor areas better described by the simplest MG model in an average area of 53% and 33%, respectively. Non-Gaussian behavior was illustrated in an average area of 37% according to the F-ratio, and 7% using AIC Weights. However, the distributions of the pixels best fitted by each of the four models suggest that MG failed to perform better than any other model in all patients, and the overall tumor area. No single diffusion model evaluated herein could accurately describe rectal tumours. These findings probably can be explained on the basis of increased tumour heterogeneity, where areas with high vascularity could be fitted better with bi-exponential models, and areas with necrosis would mostly follow mono-exponential behavior.

Structural, optical and electrical properties of CeO2 thin films simultaneously prepared by anodic and cathodic electrodeposition

NASA Astrophysics Data System (ADS)

Yang, Yumeng; Du, Xiaoqing; Yi, Chenxi; Liu, Jiao; Zhu, Benfeng; Zhang, Zhao

2018-05-01

CeO2 thin films were deposited on stainless steel (SS) and indium tin oxide (ITO)-coated glass by simultaneous anodic and cathodic electrodeposition, and the influence of negative potential on the formation of ceria films was studied with scanning electron microscopy, X-ray diffraction, Raman spectroscopy, van der Pauw measurements, UV-visible spectroscopy and X-ray photoelectron spectroscopy. The results show that CeO2 films on the anode are slightly affected by the potential, but the particle size, crystal orientation, strain, film thickness, resistivity and Ce(III) content of the films on the cathode increases with increasing potential on the SS substrate. Contradictory to the results of the SS cathode, redshift (Ed changed from 3.95 eV to 3.56 eV and Ei changed from 3.42 eV to 3.04 eV) occurring in the absorption spectrum of CeO2 deposited on the ITO-coated glass cathode indicates that the content of Ce3+ in the cathodic films is dependent on the adopted substrates and decreases as the applied potential is increased.

Quantifying non-Gaussianity for quantum information

NASA Astrophysics Data System (ADS)

Genoni, Marco G.; Paris, Matteo G. A.

2010-11-01

We address the quantification of non-Gaussianity (nG) of states and operations in continuous-variable systems and its use in quantum information. We start by illustrating in detail the properties and the relationships of two recently proposed measures of nG based on the Hilbert-Schmidt distance and the quantum relative entropy (QRE) between the state under examination and a reference Gaussian state. We then evaluate the non-Gaussianities of several families of non-Gaussian quantum states and show that the two measures have the same basic properties and also share the same qualitative behavior in most of the examples taken into account. However, we also show that they introduce a different relation of order; that is, they are not strictly monotone to each other. We exploit the nG measures for states in order to introduce a measure of nG for quantum operations, to assess Gaussification and de-Gaussification protocols, and to investigate in detail the role played by nG in entanglement-distillation protocols. Besides, we exploit the QRE-based nG measure to provide different insight on the extremality of Gaussian states for some entropic quantities such as conditional entropy, mutual information, and the Holevo bound. We also deal with parameter estimation and present a theorem connecting the QRE nG to the quantum Fisher information. Finally, since evaluation of the QRE nG measure requires the knowledge of the full density matrix, we derive some experimentally friendly lower bounds to nG for some classes of states and by considering the possibility of performing on the states only certain efficient or inefficient measurements.

Quadratic forms involving Green's and Robin functions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dubinin, Vladimir N

2009-10-31

General inequalities for quadratic forms with coefficients depending on the values of Green's and Robin functions are obtained. These inequalities cover also the reduced moduli of strips and half-strips. Some applications of the results obtained to extremal partitioning problems and related questions of geometric function theory are discussed. Bibliography: 29 titles.

How Gaussian can our Universe be?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabass, G.; Pajer, E.; Schmidt, F., E-mail: giovanni.cabass@roma1.infn.it, E-mail: e.pajer@uu.nl, E-mail: fabians@mpa-garching.mpg.de

Gravity is a non-linear theory, and hence, barring cancellations, the initial super-horizon perturbations produced by inflation must contain some minimum amount of mode coupling, or primordial non-Gaussianity. In single-field slow-roll models, where this lower bound is saturated, non-Gaussianity is controlled by two observables: the tensor-to-scalar ratio, which is uncertain by more than fifty orders of magnitude; and the scalar spectral index, or tilt, which is relatively well measured. It is well known that to leading and next-to-leading order in derivatives, the contributions proportional to the tilt disappear from any local observable, and suspicion has been raised that this might happenmore » to all orders, allowing for an arbitrarily low amount of primordial non-Gaussianity. Employing Conformal Fermi Coordinates, we show explicitly that this is not the case. Instead, a contribution of order the tilt appears in local observables. In summary, the floor of physical primordial non-Gaussianity in our Universe has a squeezed-limit scaling of k {sub ℓ}{sup 2}/ k {sub s} {sup 2}, similar to equilateral and orthogonal shapes, and a dimensionless amplitude of order 0.1 × ( n {sub s}−1).« less

Hexahedron Prism-Anchored Octahedronal CeO2: Crystal Facet-Based Homojunction Promoting Efficient Solar Fuel Synthesis.

PubMed

Li, Ping; Zhou, Yong; Zhao, Zongyan; Xu, Qinfeng; Wang, Xiaoyong; Xiao, Min; Zou, Zhigang

2015-08-05

An unprecedented, crystal facet-based CeO2 homojunction consisting of hexahedron prism-anchored octahedron with exposed prism surface of {100} facets and octahedron surface of {111} facets was fabricated through solution-based crystallographic-oriented epitaxial growth. The photocatalysis experiment reveals that growth of the prism arm on octahedron allows to activate inert CeO2 octahedron for an increase in phototocatalytic reduction of CO2 into methane. The pronounced photocatalytic performance is attributed to a synergistic effect of the following three factors: (1) band alignment of the {100} and {111} drives electrons and holes to octahedron and prism surfaces, respectively, aiming to reach the most stable energy configuration and leading to a spatial charge separation for long duration; (2) crystallographic-oriented epitaxial growth of the CeO2 hexahedron prism arm on the octahedron verified by the interfacial lattice fringe provides convenient and fast channels for the photogenerated carrier transportation between two units of homojuntion; (3) different effective mass of electrons and holes on {100} and {111} faces leads to high charge carrier mobility, more facilitating the charge separation. The proposed facet-based homojunction in this work may provide a new concept for the efficient separation and fast transfer of photoinduced charge carriers and enhancement of the photocatalytic performance.

The DIAS/CEOS Water Portal, distributed system using brokering architecture

NASA Astrophysics Data System (ADS)

Miura, Satoko; Sekioka, Shinichi; Kuroiwa, Kaori; Kudo, Yoshiyuki

2015-04-01

The DIAS/CEOS Water Portal is a one of the DIAS (Data Integration and Analysis System, http://www.editoria.u-tokyo.ac.jp/projects/dias/?locale=en_US) systems for data distribution for users including, but not limited to, scientists, decision makers and officers like river administrators. This portal has two main functions; one is to search and access data and the other is to register and share use cases which use datasets provided via this portal. This presentation focuses on the first function, to search and access data. The Portal system is distributed in the sense that, while the portal system is located in Tokyo, the data is located in archive centers which are globally distributed. For example, some in-situ data is archived at the National Center for Atmospheric Research (NCAR) Earth Observing Laboratory in Boulder, Colorado, USA. The NWP station time series and global gridded model output data is archived at the Max Planck Institute for Meteorology (MPIM) in cooperation with the World Data Center for Climate in Hamburg, Germany. Part of satellite data is archived at DIAS storage at the University of Tokyo, Japan. This portal itself does not store data. Instead, according to requests made by users on the web page, it retrieves data from distributed data centers on-the-fly and lets them download and see rendered images/plots. Although some data centers have unique meta data format and/or data search protocols, our portal's brokering function enables users to search across various data centers at one time, like one-stop shopping. And this portal is also connected to other data brokering systems, including GEOSS DAB (Discovery and Access Broker). As a result, users can search over thousands of datasets, millions of files at one time. Our system mainly relies on the open source software GI-cat (http://essi-lab.eu/do/view/GIcat), Opensearch protocol and OPeNDAP protocol to enable the above functions. Details on how it works will be introduced during the

Role of CeO2 promoter in NiO/α-Al2O3 catalyst for dry reforming of methane

NASA Astrophysics Data System (ADS)

Loc, Luu Cam; Phuong, Phan Hong; Tri, Nguyen

2017-09-01

A series of Ni/α-Al2O3 (NiAl) catalysts promoted by CeO2 was prepared by co-impregnation methods with content of (NiO+CeO2) being in the range of 10-30 wt%. The NiO:CeO2 weight ratio was fluctuated at 1:1, 1:2 and 1:3. Several techniques, including X-ray powder diffraction (XRD), Hydrogen temperature-programmed reduction (H2-TPR), and transmission electron microscopy (TEM) were used to investigate catalysts' physico-chemical properties. The activity of these catalysts in dry reforming of CH4 was investigated at temperature range of 550-800 °C. The results revealed that the most suitable CeO2 promoted Ni catalyst contained 20 wt% of (NiO+CeO2) and NiO:CeO2 weight ratio of 1:2. The best catalytic performance of catalyst [20(1Ni2Ce)Al] due to a better reducibility resulted in a higher amount of free small particle NiO. At 700 °C and CH4:CO2 molar ratio of 1:1, the conversion of CH4 and CO2 on the most suitable CeO2 promoted Ni catalyst reached 86% and 67%, respectively; H2 and CO selectivity of 90% and H2:CO molar ratio of 1.15 were obtained. Being similar to MgO [1], promoter CeO2 could improve catalytic activity of Ni/α-Al2O3 catalyst at a lower range of temperature. Besides, both MgO and CeO2 had a great impact on improving coke resistance of Ni catalysts. At higher temperature, the role of CeO2 as well as MgO in preventing coke formation on catalyst was clarified by temperature-programmed oxidation (TPO) technique. Coke amount formed after 30-h TOS on 20(1Ni2Ce) catalyst was found to be 22.18 mgC/gcat, being less than on non-promoted catalyst (36.75 mgC/gcat), but more than on 20(1Ni2Mg)Al one (5.25 mgC/gcat).

The Last Word: An Interview with Gene Chasin, CEO of Accelerated Schools Plus

ERIC Educational Resources Information Center

Siegle, Del

2006-01-01

This article presents an interview with Gene Chasin, CEO of Accelerated Schools Plus. Chasin discusses changing schools and improving student achievement. Accelerated Schools is a national endeavor that is designed to transform whole school communities. It views the community as being much broader. It includes students, teachers, parents, other…

Designed Synthesis of CeO2 Nanorods and Nanowires for Studying Toxicological Effects of High Aspect Ratio Nanomaterials

PubMed Central

Ji, Zhaoxia; Wang, Xiang; Zhang, Haiyuan; Lin, Sijie; Meng, Huan; Sun, Bingbing; George, Saji; Xia, Tian; Nel, André E.; Zink, Jeffrey I.

2012-01-01

While it has been shown that high aspect ratio nanomaterials like carbon nanotubes and TiO2 nanowires can induce toxicity by acting as fiber-like substances that damage the lysosome, it is not clear what the critical lengths and aspect ratios are that induce this type of toxicity. To answer this question, we synthesized a series of cerium oxide (CeO2) nanorods and nanowires with precisely controlled lengths and aspect ratios. Both phosphate and chloride ions were shown to play critical roles in obtaining these high aspect ratio nanostructures. High resolution TEM analysis shows that single crystalline CeO2 nanorods/nanowires were formed along the [211] direction by an “oriented attachment” mechanism, followed by Ostwald ripening. The successful creation of a comprehensive CeO2 nanorod/nanowire combinatorial library allows, for the first time, the systematic study of the effect of aspect ratio on lysosomal damage, cytoxicity and IL-1β production by the human myeloid cell line (THP-1). This in vitro toxicity study demonstrated that at lengths ≥200 nm and aspect ratios ≥ 22, CeO2 nanorods induced progressive cytotoxicity and pro-inflammatory effects. The relatively low “critical” length and aspect ratio were associated with small nanorod/nanowire diameters (6–10 nm), which facilitates the formation of stacking bundles due to strong van der Waals and dipole-dipole attractions. Our results suggest that both length and diameter components of aspect ratio should be considered when addressing the cytotoxic effects of long aspect ratio materials. PMID:22564147

Efficiency of the human observer for detecting a Gaussian signal at a known location in non-Gaussian distributed lumpy backgrounds.

PubMed

Park, Subok; Gallas, Bradon D; Badano, Aldo; Petrick, Nicholas A; Myers, Kyle J

2007-04-01

A previous study [J. Opt. Soc. Am. A22, 3 (2005)] has shown that human efficiency for detecting a Gaussian signal at a known location in non-Gaussian distributed lumpy backgrounds is approximately 4%. This human efficiency is much less than the reported 40% efficiency that has been documented for Gaussian-distributed lumpy backgrounds [J. Opt. Soc. Am. A16, 694 (1999) and J. Opt. Soc. Am. A18, 473 (2001)]. We conducted a psychophysical study with a number of changes, specifically in display-device calibration and data scaling, from the design of the aforementioned study. Human efficiency relative to the ideal observer was found again to be approximately 5%. Our variance analysis indicates that neither scaling nor display made a statistically significant difference in human performance for the task. We conclude that the non-Gaussian distributed lumpy background is a major factor in our low human-efficiency results.

Plasma-catalyst hybrid reactor with CeO2/γ-Al2O3 for benzene decomposition with synergetic effect and nano particle by-product reduction.

PubMed

Mao, Lingai; Chen, Zhizong; Wu, Xinyue; Tang, Xiujuan; Yao, Shuiliang; Zhang, Xuming; Jiang, Boqiong; Han, Jingyi; Wu, Zuliang; Lu, Hao; Nozaki, Tomohiro

2018-04-05

A dielectric barrier discharge (DBD) catalyst hybrid reactor with CeO 2 /γ-Al 2 O 3 catalyst balls was investigated for benzene decomposition at atmospheric pressure and 30 °C. At an energy density of 37-40 J/L, benzene decomposition was as high as 92.5% when using the hybrid reactor with 5.0wt%CeO 2 /γ-Al 2 O 3 ; while it was 10%-20% when using a normal DBD reactor without a catalyst. Benzene decomposition using the hybrid reactor was almost the same as that using an O 3 catalyst reactor with the same CeO 2 /γ-Al 2 O 3 catalyst, indicating that O 3 plays a key role in the benzene decomposition. Fourier transform infrared spectroscopy analysis showed that O 3 adsorption on CeO 2 /γ-Al 2 O 3 promotes the production of adsorbed O 2 - and O 2 2‒ , which contribute benzene decomposition over heterogeneous catalysts. Nano particles as by-products (phenol and 1,4-benzoquinone) from benzene decomposition can be significantly reduced using the CeO 2 /γ-Al 2 O 3 catalyst. H 2 O inhibits benzene decomposition; however, it improves CO 2 selectivity. The deactivated CeO 2 /γ-Al 2 O 3 catalyst can be regenerated by performing discharges at 100 °C and 192-204 J/L. The decomposition mechanism of benzene over CeO 2 /γ-Al 2 O 3 catalyst was proposed. Copyright © 2017 Elsevier B.V. All rights reserved.

Cosine-Gaussian Schell-model sources.

PubMed

Mei, Zhangrong; Korotkova, Olga

2013-07-15

We introduce a new class of partially coherent sources of Schell type with cosine-Gaussian spectral degree of coherence and confirm that such sources are physically genuine. Further, we derive the expression for the cross-spectral density function of a beam generated by the novel source propagating in free space and analyze the evolution of the spectral density and the spectral degree of coherence. It is shown that at sufficiently large distances from the source the degree of coherence of the propagating beam assumes Gaussian shape while the spectral density takes on the dark-hollow profile.

Semisupervised Gaussian Process for Automated Enzyme Search.

PubMed

Mellor, Joseph; Grigoras, Ioana; Carbonell, Pablo; Faulon, Jean-Loup

2016-06-17

Synthetic biology is today harnessing the design of novel and greener biosynthesis routes for the production of added-value chemicals and natural products. The design of novel pathways often requires a detailed selection of enzyme sequences to import into the chassis at each of the reaction steps. To address such design requirements in an automated way, we present here a tool for exploring the space of enzymatic reactions. Given a reaction and an enzyme the tool provides a probability estimate that the enzyme catalyzes the reaction. Our tool first considers the similarity of a reaction to known biochemical reactions with respect to signatures around their reaction centers. Signatures are defined based on chemical transformation rules by using extended connectivity fingerprint descriptors. A semisupervised Gaussian process model associated with the similar known reactions then provides the probability estimate. The Gaussian process model uses information about both the reaction and the enzyme in providing the estimate. These estimates were validated experimentally by the application of the Gaussian process model to a newly identified metabolite in Escherichia coli in order to search for the enzymes catalyzing its associated reactions. Furthermore, we show with several pathway design examples how such ability to assign probability estimates to enzymatic reactions provides the potential to assist in bioengineering applications, providing experimental validation to our proposed approach. To the best of our knowledge, the proposed approach is the first application of Gaussian processes dealing with biological sequences and chemicals, the use of a semisupervised Gaussian process framework is also novel in the context of machine learning applied to bioinformatics. However, the ability of an enzyme to catalyze a reaction depends on the affinity between the substrates of the reaction and the enzyme. This affinity is generally quantified by the Michaelis constant KM

Gaussian statistics for palaeomagnetic vectors

USGS Publications Warehouse

Love, J.J.; Constable, C.G.

2003-01-01

With the aim of treating the statistics of palaeomagnetic directions and intensities jointly and consistently, we represent the mean and the variance of palaeomagnetic vectors, at a particular site and of a particular polarity, by a probability density function in a Cartesian three-space of orthogonal magnetic-field components consisting of a single (unimoda) non-zero mean, spherically-symmetrical (isotropic) Gaussian function. For palaeomagnetic data of mixed polarities, we consider a bimodal distribution consisting of a pair of such symmetrical Gaussian functions, with equal, but opposite, means and equal variances. For both the Gaussian and bi-Gaussian distributions, and in the spherical three-space of intensity, inclination, and declination, we obtain analytical expressions for the marginal density functions, the cumulative distributions, and the expected values and variances for each spherical coordinate (including the angle with respect to the axis of symmetry of the distributions). The mathematical expressions for the intensity and off-axis angle are closed-form and especially manageable, with the intensity distribution being Rayleigh-Rician. In the limit of small relative vectorial dispersion, the Gaussian (bi-Gaussian) directional distribution approaches a Fisher (Bingham) distribution and the intensity distribution approaches a normal distribution. In the opposite limit of large relative vectorial dispersion, the directional distributions approach a spherically-uniform distribution and the intensity distribution approaches a Maxwell distribution. We quantify biases in estimating the properties of the vector field resulting from the use of simple arithmetic averages, such as estimates of the intensity or the inclination of the mean vector, or the variances of these quantities. With the statistical framework developed here and using the maximum-likelihood method, which gives unbiased estimates in the limit of large data numbers, we demonstrate how to

Gaussian statistics for palaeomagnetic vectors

NASA Astrophysics Data System (ADS)

Love, J. J.; Constable, C. G.

2003-03-01

With the aim of treating the statistics of palaeomagnetic directions and intensities jointly and consistently, we represent the mean and the variance of palaeomagnetic vectors, at a particular site and of a particular polarity, by a probability density function in a Cartesian three-space of orthogonal magnetic-field components consisting of a single (unimodal) non-zero mean, spherically-symmetrical (isotropic) Gaussian function. For palaeomagnetic data of mixed polarities, we consider a bimodal distribution consisting of a pair of such symmetrical Gaussian functions, with equal, but opposite, means and equal variances. For both the Gaussian and bi-Gaussian distributions, and in the spherical three-space of intensity, inclination, and declination, we obtain analytical expressions for the marginal density functions, the cumulative distributions, and the expected values and variances for each spherical coordinate (including the angle with respect to the axis of symmetry of the distributions). The mathematical expressions for the intensity and off-axis angle are closed-form and especially manageable, with the intensity distribution being Rayleigh-Rician. In the limit of small relative vectorial dispersion, the Gaussian (bi-Gaussian) directional distribution approaches a Fisher (Bingham) distribution and the intensity distribution approaches a normal distribution. In the opposite limit of large relative vectorial dispersion, the directional distributions approach a spherically-uniform distribution and the intensity distribution approaches a Maxwell distribution. We quantify biases in estimating the properties of the vector field resulting from the use of simple arithmetic averages, such as estimates of the intensity or the inclination of the mean vector, or the variances of these quantities. With the statistical framework developed here and using the maximum-likelihood method, which gives unbiased estimates in the limit of large data numbers, we demonstrate how to

Self-Template Synthesis of Hybrid Porous Co3 O4 -CeO2 Hollow Polyhedrons for High-Performance Supercapacitors.

PubMed

Wei, Chengzhen; Liu, Kangfei; Tao, Jing; Kang, Xiaoting; Hou, Haiyan; Cheng, Cheng; Zhang, Daojun

2018-01-04

In this work, hybrid porous Co 3 O 4 -CeO 2 hollow polyhedrons have been successfully obtained via a simple cation-exchange route followed by heat treatment. In the synthesis process, ZIF-67 polyhedron frameworks are firstly prepared, which not only serve as a host for the exchanged Ce3 + ions but also act as the template for the synthesis of hybrid porous Co 3 O 4 -CeO 2 hollow polyhedrons. When utilized as electrode materials for supercapacitors, the hybrid porous Co 3 O 4 -CeO 2 hollow polyhedrons delivered a large specific capacitance of 1288.3 F g -1 at 2.5 A g -1 and a remarkable long lifespan cycling stability (<3.3 % loss after 6000 cycles). Furthermore, an asymmetric supercapacitor (ASC) device based on hybrid porous Co 3 O 4 -CeO 2 hollow polyhedrons was assembled. The ASC device possesses an energy density of 54.9 W h kg -1 , which can be retained to 44.2 W h kg -1 even at a power density of 5100 W kg -1 , indicating its promising application in electrochemical energy storage. More importantly, we believe that the present route is a simple and versatile strategy for the preparation of other hybrid metal oxides with desired structures, chemical compositions and applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Consistency relations for sharp inflationary non-Gaussian features

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mooij, Sander; Palma, Gonzalo A.; Panotopoulos, Grigoris

If cosmic inflation suffered tiny time-dependent deviations from the slow-roll regime, these would induce the existence of small scale-dependent features imprinted in the primordial spectra, with their shapes and sizes revealing information about the physics that produced them. Small sharp features could be suppressed at the level of the two-point correlation function, making them undetectable in the power spectrum, but could be amplified at the level of the three-point correlation function, offering us a window of opportunity to uncover them in the non-Gaussian bispectrum. In this article, we show that sharp features may be analyzed using only data coming frommore » the three point correlation function parametrizing primordial non-Gaussianity. More precisely, we show that if features appear in a particular non-Gaussian triangle configuration (e.g. equilateral, folded, squeezed), these must reappear in every other configuration according to a specific relation allowing us to correlate features across the non-Gaussian bispectrum. As a result, we offer a method to study scale-dependent features generated during inflation that depends only on data coming from measurements of non-Gaussianity, allowing us to omit data from the power spectrum.« less

The impact of non-Gaussianity upon cosmological forecasts

NASA Astrophysics Data System (ADS)

Repp, A.; Szapudi, I.; Carron, J.; Wolk, M.

2015-12-01

The primary science driver for 3D galaxy surveys is their potential to constrain cosmological parameters. Forecasts of these surveys' effectiveness typically assume Gaussian statistics for the underlying matter density, despite the fact that the actual distribution is decidedly non-Gaussian. To quantify the effect of this assumption, we employ an analytic expression for the power spectrum covariance matrix to calculate the Fisher information for Baryon Acoustic Oscillation (BAO)-type model surveys. We find that for typical number densities, at kmax = 0.5h Mpc-1, Gaussian assumptions significantly overestimate the information on all parameters considered, in some cases by up to an order of magnitude. However, after marginalizing over a six-parameter set, the form of the covariance matrix (dictated by N-body simulations) causes the majority of the effect to shift to the `amplitude-like' parameters, leaving the others virtually unaffected. We find that Gaussian assumptions at such wavenumbers can underestimate the dark energy parameter errors by well over 50 per cent, producing dark energy figures of merit almost three times too large. Thus, for 3D galaxy surveys probing the non-linear regime, proper consideration of non-Gaussian effects is essential.

On the robustness of the q-Gaussian family

NASA Astrophysics Data System (ADS)

Sicuro, Gabriele; Tempesta, Piergiulio; Rodríguez, Antonio; Tsallis, Constantino

2015-12-01

We introduce three deformations, called α-, β- and γ-deformation respectively, of a N-body probabilistic model, first proposed by Rodríguez et al. (2008), having q-Gaussians as N → ∞ limiting probability distributions. The proposed α- and β-deformations are asymptotically scale-invariant, whereas the γ-deformation is not. We prove that, for both α- and β-deformations, the resulting deformed triangles still have q-Gaussians as limiting distributions, with a value of q independent (dependent) on the deformation parameter in the α-case (β-case). In contrast, the γ-case, where we have used the celebrated Q-numbers and the Gauss binomial coefficients, yields other limiting probability distribution functions, outside the q-Gaussian family. These results suggest that scale-invariance might play an important role regarding the robustness of the q-Gaussian family.

The CEOS Global Observation Strategy for Disaster Risk Management: An Enterprise Architect's View

NASA Astrophysics Data System (ADS)

Moe, K.; Evans, J. D.; Frye, S.

2013-12-01

The Committee on Earth Observation Satellites (CEOS) Working Group on Information Systems and Services (WGISS), on behalf of the Global Earth Observation System of Systems (GEOSS), is defining an enterprise architecture (known as GA.4.D) for the use of satellite observations in international disaster management. This architecture defines the scope and structure of the disaster management enterprise (based on disaster types and phases); its processes (expressed via use cases / system functions); and its core values (in particular, free and open data sharing via standard interfaces). The architecture also details how a disaster management enterprise describes, obtains, and handles earth observations and data products for decision-support; and how it draws on distributed computational services for streamlined operational capability. We have begun to apply this architecture to a new CEOS initiative, the Global Observation Strategy for Disaster Risk Management (DRM). CEOS is defining this Strategy based on the outcomes of three pilot projects focused on seismic hazards, volcanoes, and floods. These pilots offer a unique opportunity to characterize and assess the impacts (benefits / costs) of the GA.4.D architecture in practice. In particular, the DRM Floods Pilot is applying satellite-based optical and radar data to flood mitigation, warning, and response, including monitoring and modeling at regional to global scales. It is focused on serving user needs and building local institutional / technical capacity in the Caribbean, Southern Africa, and Southeast Asia. In the context of these CEOS DRM Pilots, we are characterizing where and how the GA.4D architecture helps participants to: - Understand the scope and nature of hazard events quickly and accurately - Assure timely delivery of observations into analysis, modeling, and decision-making - Streamline user access to products - Lower barriers to entry for users or suppliers - Streamline or focus field operations in

Molecular dynamics simulation of fast particle irradiation on the single crystal CeO2

NASA Astrophysics Data System (ADS)

Sasajima, Y.; Ajima, N.; Osada, T.; Ishikawa, N.; Iwase, A.

2013-11-01

We used a molecular dynamics method to simulate structural relaxation caused by the high-energy-ion irradiation of single crystal CeO2. As the initial condition, we assumed high thermal energy was supplied to the individual atoms within a cylindrical region of nanometer-order diameter located in the center of the single crystal. The potential proposed by Inaba et al. was utilized to calculate interactions between atoms [H. Inaba, R. Sagawa, H. Hayashi, K. Kawamura, Solid State Ionics 122 (1999) 95-103]. The supplied thermal energy was first spent to change the crystal structure into an amorphous one within a short period of about 0.3 ps, then it was dissipated in the crystal. We compared the obtained results with those of computer simulations for UO2 and found that CeO2 was more stable than UO2 when supplied with high thermal energy.

Weakly anomalous diffusion with non-Gaussian propagators

NASA Astrophysics Data System (ADS)

Cressoni, J. C.; Viswanathan, G. M.; Ferreira, A. S.; da Silva, M. A. A.

2012-08-01

A poorly understood phenomenon seen in complex systems is diffusion characterized by Hurst exponent H≈1/2 but with non-Gaussian statistics. Motivated by such empirical findings, we report an exact analytical solution for a non-Markovian random walk model that gives rise to weakly anomalous diffusion with H=1/2 but with a non-Gaussian propagator.

Skewness in large-scale structure and non-Gaussian initial conditions

NASA Technical Reports Server (NTRS)

Fry, J. N.; Scherrer, Robert J.

1994-01-01

We compute the skewness of the galaxy distribution arising from the nonlinear evolution of arbitrary non-Gaussian intial conditions to second order in perturbation theory including the effects of nonlinear biasing. The result contains a term identical to that for a Gaussian initial distribution plus terms which depend on the skewness and kurtosis of the initial conditions. The results are model dependent; we present calculations for several toy models. At late times, the leading contribution from the initial skewness decays away relative to the other terms and becomes increasingly unimportant, but the contribution from initial kurtosis, previously overlooked, has the same time dependence as the Gaussian terms. Observations of a linear dependence of the normalized skewness on the rms density fluctuation therefore do not necessarily rule out initially non-Gaussian models. We also show that with non-Gaussian initial conditions the first correction to linear theory for the mean square density fluctuation is larger than for Gaussian models.

Quadratic electroabsorption studies of molecular motion in dye-doped polymers

NASA Astrophysics Data System (ADS)

Poga, Constantina; Kuzyk, Mark G.; Dirk, Carl W.

1993-02-01

This paper reports on quadratic electroabsorption studies of thin-film solid solutions of squarylium dye molecules in poly(methylmethacrylate) polymer with the aim of understanding the role of electronic and reorientational mechanisms in the third-order nonlinear-optical susceptibility. We present a generalized theory of the quadratic electrooptic response that includes both electronic mechanisms and molecular reorientation and show that the ratio of two independent third-order susceptibility tensor components, namely (chi) (3)3333/(chi) (3)1133, determines the relative contribution of each mechanism. Based on these theoretical results, we have designed and built an experiment that determines this ratio as a function of temperature and wavelength. Results show that at room temperature and near the first electronic transition wavelength, the response is dominated by the electronic mechanism, and that the reorientational contribution dominates when the sample is heated above its glass transition temperature. Furthermore, results show that, off-resonance, the sign of the imaginary part of the third-order susceptibility is positive. Quadratic electroabsorption is thus shown to be a versatile tool for measuring the imaginary part of the third-order nonlinear-optical susceptibility which yields information about the interaction of polymer and dopant molecule.

Integration of the Quadratic Function and Generalization

ERIC Educational Resources Information Center

Mitsuma, Kunio

2011-01-01

We will first recall useful formulas in integration that simplify the calculation of certain definite integrals with the quadratic function. A main formula relies only on the coefficients of the function. We will then explore a geometric proof of one of these formulas. Finally, we will extend the formulas to more general cases. (Contains 3…

The Classification for Early-onset Scoliosis (C-EOS) Correlates With the Speed of Vertical Expandable Prosthetic Titanium Rib (VEPTR) Proximal Anchor Failure

PubMed Central

Park, Howard Y.; Matsumoto, Hiroko; Feinberg, Nicholas; Roye, David P.; Kanj, Wajdi W.; Betz, Randal R.; Cahill, Patrick J.; Glotzbecker, Michael P.; Luhmann, Scott J.; Garg, Sumeet; Sawyer, Jeffrey R.; Smith, John T.; Flynn, John M.; Vitale, Michael G.

2017-01-01