Scoring recognizability of faces for security applications
NASA Astrophysics Data System (ADS)
Bianco, Simone; Ciocca, Gianluigi; Guarnera, Giuseppe Claudio; Scaggiante, Andrea; Schettini, Raimondo
2014-03-01
In security applications the human face plays a fundamental role, however we have to assume non-collaborative subjects. A face can be partially visible or occluded due to common-use accessories such as sunglasses, hats, scarves and so on. Also the posture of the head influence the face recognizability. Given a video sequence in input, the proposed system is able to establish if a face is depicted in a frame, and to determine its degree of recognizability in terms of clearly visible facial features. The system implements features filtering scheme combined with a skin-based face detection to improve its the robustness to false positives and cartoon-like faces. Moreover the system takes into account the recognizability trend over a customizable sliding time window to allow a high level analysis of the subject behaviour. The recognizability criteria can be tuned for each specific application. We evaluate our system both in qualitative and quantitative terms, using a data set of manually annotated videos. Experimental results confirm the effectiveness of the proposed system.
ERIC Educational Resources Information Center
Jones, Robyn L.
2011-01-01
Within this article, the author presents a personal story, "Leaving," which highlights the problematic experience of opposing established practice. The tale tells of the difficulty faced by creative agency when confronted by a constraining structural hegemony. Specifically, it draws attention to the professionalization of academic life through a…
Change deafness and object encoding with recognizable and unrecognizable sounds.
Gregg, Melissa K; Irsik, Vanessa C; Snyder, Joel S
2014-08-01
Change deafness is the failure to notice changes in an auditory scene. In this study, we sought to determine if change deafness is a perceptual error, rather than only a reflection of verbal memory limitations. We also examined how successful encoding of objects within a scene is related to successful detection of changes. Event-related potentials (ERPs) were recorded while listeners completed a change-detection and an object-encoding task with scenes composed of recognizable sounds or unrecognizable temporally scrambled versions of the recognizable sounds. More change deafness occurred for the unrecognizable, compared to recognizable sounds, indicating that change deafness is a perceptual error and not solely a product of verbal memory. ERPs from both the recognizable and unrecognizable scenes revealed an enhanced P3b (at PZ/1/2, POZ/3/4 from 350 to 750ms) to detected changes, a marker that conscious change detection has occurred. Recognizable scenes resulted in an enhanced T400 (at T8/TP8, C6/CP6 from 315 to 660ms) to detected changes, possibly indicating activation of established memory representations. Unrecognizable scenes elicited an enhanced P3a (at FCZ/1/2 from 280 to 600ms) to detected changes, indicating enhanced orienting to acoustic change. Performance on the object-encoding task revealed that change deafness was reduced, but not eliminated, when performance on the object-encoding task was accurate. PMID:24937187
32 CFR 884.4 - Release on bail or recognizance.
Code of Federal Regulations, 2011 CFR
2011-07-01
... Classification. 3 If contact cannot be made with the member's commander, the Air Force unit, activity, or... 884.4 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE MILITARY... recognizance. (a) Before delivering an Air Force member to a civilian authority, the commander or...
32 CFR 884.4 - Release on bail or recognizance.
Code of Federal Regulations, 2010 CFR
2010-07-01
... Classification. 3 If contact cannot be made with the member's commander, the Air Force unit, activity, or... 884.4 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE MILITARY... recognizance. (a) Before delivering an Air Force member to a civilian authority, the commander or...
Accidental degeneracies in string compactification
NASA Astrophysics Data System (ADS)
Bais, F. A.; Taormina, A.
1986-11-01
The equivalence of the torus and group manifold compactification of strings is established. Accidental degeneracies are shown to occur for a large class of compactifications. This way many examples are obtained in which modular invariance does not uniquely fix the representation content of the spectrum.
Overcoming Degeneracies in Exoplanet Spectra
NASA Astrophysics Data System (ADS)
Benneke, Björn
2015-08-01
Spectroscopic observations of exoplanets can provide invaluable insights into the planets’ compositions, their formation and evolution histories, and even their habitability. Obtaining exoplanet spectra is observationally challenging; however, and we are generally limited to relatively low signal-to-noise, low spectral resolution, disk-integrated observations , often with relatively narrow wavelength coverage. This low data situation results in strong correlations and degeneracies between the different planet and atmospheric parameters of interest. In this talk, I will present a conceptual picture of how vital information about the planet is encoded in its observable spectrum. I will then give an overview about the wide range of correlations and degeneracies relevant to today’s exoplanet observations. Finally, I will demonstrate how some degeneracies can be overcome and improved constraints can be obtained by including prior knowledge of atmospheric chemistry and physics in the retrieval. I present a new atmospheric retrieval framework, SCARLET, that combines observational data and our prior (limited) knowledge of atmospheric processes in a statistical robust Bayesian framework. New results for hot Jupiters will be presented.
Coping with degeneracies in Delaunay triangulation
Beichl, I.; Sullivan, F.
1995-12-31
Degeneracy is a serious issue in geometry. In their original form, many geometric algorithms simply assume that there is no degeneracy. As a result, when these methods are used on data that is degenerate or nearly degenerate, they either fail to complete or else give nonsensical results. We will describe a new method that removes only those 3-d degeneracies that cause ambiguity in determining Delaunay tetrahedra and only those 3-d degeneracies that cause ambiguity in determining Delaunay triangles. The mathematical justification is based on classical results of real analysis. The proof identifies degeneracies with the polynomial derived from the determinants that express geometrical primitives. Our result is a probabilistic statement about the real numbers; with probability one, degeneracies are removed in real arithmetic. In floating-point arithmetic, detection of degeneracies is based on relative error criteria that we describe here.
Auditory Sketches: Very Sparse Representations of Sounds Are Still Recognizable
Isnard, Vincent; Taffou, Marine; Viaud-Delmon, Isabelle; Suied, Clara
2016-01-01
Sounds in our environment like voices, animal calls or musical instruments are easily recognized by human listeners. Understanding the key features underlying this robust sound recognition is an important question in auditory science. Here, we studied the recognition by human listeners of new classes of sounds: acoustic and auditory sketches, sounds that are severely impoverished but still recognizable. Starting from a time-frequency representation, a sketch is obtained by keeping only sparse elements of the original signal, here, by means of a simple peak-picking algorithm. Two time-frequency representations were compared: a biologically grounded one, the auditory spectrogram, which simulates peripheral auditory filtering, and a simple acoustic spectrogram, based on a Fourier transform. Three degrees of sparsity were also investigated. Listeners were asked to recognize the category to which a sketch sound belongs: singing voices, bird calls, musical instruments, and vehicle engine noises. Results showed that, with the exception of voice sounds, very sparse representations of sounds (10 features, or energy peaks, per second) could be recognized above chance. No clear differences could be observed between the acoustic and the auditory sketches. For the voice sounds, however, a completely different pattern of results emerged, with at-chance or even below-chance recognition performances, suggesting that the important features of the voice, whatever they are, were removed by the sketch process. Overall, these perceptual results were well correlated with a model of auditory distances, based on spectro-temporal excitation patterns (STEPs). This study confirms the potential of these new classes of sounds, acoustic and auditory sketches, to study sound recognition. PMID:26950589
Nodal surfaces and interdimensional degeneracies
Loos, Pierre-François; Bressanini, Dario
2015-06-07
The aim of this paper is to shed light on the topology and properties of the nodes (i.e., the zeros of the wave function) in electronic systems. Using the “electrons on a sphere” model, we study the nodes of two-, three-, and four-electron systems in various ferromagnetic configurations (sp, p{sup 2}, sd, pd, p{sup 3}, sp{sup 2}, and sp{sup 3}). In some particular cases (sp, p{sup 2}, sd, pd, and p{sup 3}), we rigorously prove that the non-interacting wave function has the same nodes as the exact (yet unknown) wave function. The number of atomic and molecular systems for which the exact nodes are known analytically is very limited and we show here that this peculiar feature can be attributed to interdimensional degeneracies. Although we have not been able to prove it rigorously, we conjecture that the nodes of the non-interacting wave function for the sp{sup 3} configuration are exact.
The effective degeneracy of protein normal modes
NASA Astrophysics Data System (ADS)
Na, Hyuntae; Song, Guang
2016-06-01
Normal modes are frequently computed and used to portray protein dynamics and interpret protein conformational changes. In this work, we investigate the nature of normal modes and find that the normal modes of proteins, especially those at the low frequency range (0–600 cm‑1), are highly susceptible to degeneracy. Two or more modes are degenerate if they have the same frequency and consequently any orthogonal transformation of them also is a valid representation of the mode subspace. Thus, degenerate modes can no longer characterize unique directions of motions as regular modes do. Though the normal modes of proteins are usually of different frequencies, the difference in frequency between neighboring modes is so small that, under even slight structural uncertainty that unavoidably exists in structure determination, it can easily vanish and as a result, a mode becomes effectively degenerate with its neighboring modes. This can be easily observed in that some modes seem to disappear and their matching modes cannot be found when the structure used to compute the modes is modified only slightly. We term this degeneracy the effective degeneracy of normal modes. This work is built upon our recent discovery that the vibrational spectrum of globular proteins is universal. The high density of modes observed in the vibrational frequency spectra of proteins renders their normal modes highly susceptible to degeneracy, under even the smallest structural uncertainty. Indeed, we find the degree of degeneracy of modes is proportional to the density of modes in the vibrational spectrum. This means that for modes at the same frequency, degeneracy is more severe for larger proteins. Degeneracy exists also in the modes of coarse-grained models, but to a much lesser extent than those of all-atom models. In closing, we discuss the implications of the effective degeneracy of normal modes: how it may significantly affect the ways in which normal modes are used in various normal modes
The effective degeneracy of protein normal modes.
Na, Hyuntae; Song, Guang
2016-01-01
Normal modes are frequently computed and used to portray protein dynamics and interpret protein conformational changes. In this work, we investigate the nature of normal modes and find that the normal modes of proteins, especially those at the low frequency range (0-600 cm(-1)), are highly susceptible to degeneracy. Two or more modes are degenerate if they have the same frequency and consequently any orthogonal transformation of them also is a valid representation of the mode subspace. Thus, degenerate modes can no longer characterize unique directions of motions as regular modes do. Though the normal modes of proteins are usually of different frequencies, the difference in frequency between neighboring modes is so small that, under even slight structural uncertainty that unavoidably exists in structure determination, it can easily vanish and as a result, a mode becomes effectively degenerate with its neighboring modes. This can be easily observed in that some modes seem to disappear and their matching modes cannot be found when the structure used to compute the modes is modified only slightly. We term this degeneracy the effective degeneracy of normal modes. This work is built upon our recent discovery that the vibrational spectrum of globular proteins is universal. The high density of modes observed in the vibrational frequency spectra of proteins renders their normal modes highly susceptible to degeneracy, under even the smallest structural uncertainty. Indeed, we find the degree of degeneracy of modes is proportional to the density of modes in the vibrational spectrum. This means that for modes at the same frequency, degeneracy is more severe for larger proteins. Degeneracy exists also in the modes of coarse-grained models, but to a much lesser extent than those of all-atom models. In closing, we discuss the implications of the effective degeneracy of normal modes: how it may significantly affect the ways in which normal modes are used in various normal modes
Quantum adiabatic evolution with energy degeneracy levels
NASA Astrophysics Data System (ADS)
Zhang, Qi
2016-01-01
A classical-kind phase-space formalism is developed to address the tiny intrinsic dynamical deviation from what is predicted by Wilczek-Zee theorem during quantum adiabatic evolution on degeneracy levels. In this formalism, the Hilbert space and the aggregate of degenerate eigenstates become the classical-kind phase space and a high-dimensional subspace in the phase space, respectively. Compared with the previous analogous study by a different method, the current result is qualitatively different in that the first-order deviation derived here is always perpendicular to the degeneracy subspace. A tripod-scheme Hamiltonian with two degenerate dark states is employed to illustrate the adiabatic deviation with degeneracy levels.
A new method to break the mass-sheet degeneracy using aperture moments
NASA Astrophysics Data System (ADS)
Rexroth, Markus; Natarajan, Priyamvada; Kneib, Jean-Paul
2016-08-01
Mass determinations from gravitational lensing shear and the higher order estimator flexion are both subject to the mass-sheet degeneracy. Mass sheet degeneracy refers to a transformation that leaves the reduced shear and flexion invariant. In general, this transformation can be approximated by the addition of a constant surface mass density sheet. We propose a new technique to break the mass-sheet degeneracy. The method uses mass moments of the shear or flexion fields in combination with convergence information derived from number counts which exploit the magnification bias. The difference between the measured mass moments provides an estimator for the magnitude of the additive constant that is the mass sheet. For demonstrating this, we derive relations that hold true in general for nth order moments and show how they can be employed effectively to break the degeneracy. We investigate the detectability of this degeneracy parameter from our method and find that the degeneracy parameter can be feasibly determined from stacked galaxy-galaxy lensing data and cluster lensing data. Furthermore, we compare the signal-to-noise ratios of convergence information from number counts with shear and flexion for singular isothermal sphere and Navarro-Frenk-White models. We find that the combination of shear and flexion performs best on galaxy and cluster scales and the convergence information can therefore be used to break the mass-sheet degeneracy without quality loss in the mass reconstruction. In summary, there is power in the combination of shear, flexion, convergence and their higher order moments. With the anticipated wealth of lensing data from upcoming and future satellite missions - EUCLID and WFIRST - this technique will be feasible.
Robust topological degeneracy of classical theories
NASA Astrophysics Data System (ADS)
Vaezi, Mohammad-Sadegh; Ortiz, Gerardo; Nussinov, Zohar
2016-05-01
We challenge the hypothesis that the ground states of a physical system whose degeneracy depends on topology must necessarily realize topological quantum order and display nonlocal entanglement. To this end, we introduce and study a classical rendition of the Toric Code model embedded on Riemann surfaces of different genus numbers. We find that the minimal ground state degeneracy (and those of all levels) depends on the topology of the embedding surface alone. As the ground states of this classical system may be distinguished by local measurements, a characteristic of Landau orders, this example illustrates that topological degeneracy is not a sufficient condition for topological quantum order. This conclusion is generic and, as shown, it applies to many other models. We also demonstrate that certain lattice realizations of these models, and other theories, display a ground state entropy (and those of all levels) that is "holographic", i.e., extensive in the system boundary. We find that clock and U (1 ) gauge theories display topological (in addition to gauge) degeneracies.
Degeneracy Breaking for K2 Microlens Parallaxes
NASA Astrophysics Data System (ADS)
Gould, Andrew; Yee, Jennifer; Carey, Sean
2015-10-01
By adding Spitzer observations to microlensing targets being observed from Kepler and Earth, we will create the first interplanetary network of microlensing observatories. This 3-observatory configuration has the unique potential to break the famous 4-fold degeneracy for space-based microlensing parallaxes. This is crucial both for the interpretation of some individual events and to rigorously validate the statistical methods that are used when (as is usually the case) this special 3-observatory configuration is not possible. The Kepler K2 C9 microlensing campaign will monitor about 4 square degrees of the Bulge from 6 Apr to 29 Jun, with the aim of measuring microlens parallaxes. Spitzer can observe this K2 field from 18 Jun to 26 Jul. The 11-day overlap between the two campaigns will allow us to break the 4-fold degeneracy of about 50 microlensing events. Some of these events will be well-covered over the peak from K2, with Spitzer observations of the falling wing providing the necessary information to break the degeneracy in the K2-Earth parallax. Others will be the reverse, with K2 observations of the rising event breaking the degeneracy in Spitzer-Earth parallaxes (i.e., for events peaking during the Spitzer campaign). Breaking this degeneracy leads to a definitive measurement of the magnitude of the microlens parallax vector, which will enable measurements of the masses and distances of the lens systems, including events with planets that contribute to the ~12 needed to make a first measurement of the Galactic distribution of planets, binaries, and many single-lens events, some of which could be black holes, brown dwarfs, or other interesting objects. The distance distribution of the ensemble of lenses can serve as a probe of Galactic structure. All lightcurves will be reduced using our customized software and then made public (for unrestricted use), within two months of the completion of observations (as we did for our 2015 observations).
On dark degeneracy and interacting models
Carneiro, S.; Borges, H.A. E-mail: humberto@ufba.br
2014-06-01
Cosmological background observations cannot fix the dark energy equation of state, which is related to a degeneracy in the definition of the dark sector components. Here we show that this degeneracy can be broken at perturbation level by imposing two observational properties on dark matter. First, dark matter is defined as the clustering component we observe in large scale structures. This definition is meaningful only if dark energy is unperturbed, which is achieved if we additionally assume, as a second condition, that dark matter is cold, i.e. non-relativistic. As a consequence, dark energy models with equation-of-state parameter −1 ≤ ω < 0 are reduced to two observationally distinguishable classes with ω = −1, equally competitive when tested against observations. The first comprises the ΛCDM model with constant dark energy density. The second consists of interacting models with an energy flux from dark energy to dark matter.
Scalar non-degeneracy and flavor unification
Kojima, Kentaro
2008-05-13
Grand unified models of the strong and electroweak forces generally predict some types of flavor unification. The flavor structure in unified theory is probed with superparticle mass spectrum observed in future particle experiments. It is shown that the generation dependence of sfermion mass non-degeneracy provides direct imprints of unification of the standard model matter multiplets. The implication from flavor-violating rare process is also discussed.
The degeneracy of the free Dirac equation
Gupta, V. . School of Physics Tata Inst. of Fundamental Research, Bombay ); McKellar, B.H.J. . School of Physics); Wu, D.D. . School of Physics Institute of High Energy Physics, Beijing, BJ . Electron LINAC Dept. General Atomics, San Diego, CA )
1991-08-01
Parity-mixed solutions of the free Dirac equation with the same 4-momentum are considered. The first-order EM energy has an electric dipole moment term whose value depends on the mixing angle. Further implications of this degeneracy to perturbative calculations are discussed. It is argued that the properties of the Dirac equation with the Coulomb potential can be used to decide the mixing angle, which should be zero.
Dark degeneracy and interacting cosmic components
Aviles, Alejandro; Cervantes-Cota, Jorge L.
2011-10-15
We study some properties of the dark degeneracy, which is the fact that what we measure in gravitational experiments is the energy-momentum tensor of the total dark sector, and any split into components (as in dark matter and dark energy) is arbitrary. In fact, just one dark fluid is necessary to obtain exactly the same cosmological and astrophysical phenomenology as the {Lambda}CDM model. We work explicitly the first-order perturbation theory and show that beyond the linear order the dark degeneracy is preserved under some general assumptions. Then we construct the dark fluid from a collection of interacting fluids. Finally, we try to break the degeneracy with a general class of couplings to baryonic matter. Nonetheless, we show that these interactions can also be understood in the context of the {Lambda}CDM model as between dark matter and baryons. For this last investigation we choose two independent parametrizations for the interactions, one inspired by electromagnetism and the other by chameleon theories. Then, we constrain them with a joint analysis of CMB and supernovae observational data.
Hidden in plain view: degeneracy in complex systems.
Mason, P H; Domínguez D, J F; Winter, B; Grignolio, A
2015-02-01
Degeneracy is a word with two meanings. The popular usage of the word denotes deviance and decay. In scientific discourse, degeneracy refers to the idea that different pathways can lead to the same output. In the biological sciences, the concept of degeneracy has been ignored for a few key reasons. Firstly, the word "degenerate" in popular culture has negative, emotionally powerful associations that do not inspire scientists to consider its technical meaning. Secondly, the tendency of searching for single causes of natural and social phenomena means that scientists can overlook the multi-stranded relationships between cause and effect. Thirdly, degeneracy and redundancy are often confused with each other. Degeneracy refers to dissimilar structures that are functionally similar while redundancy refers to identical structures. Degeneracy can give rise to novelty in ways that redundancy cannot. From genetic codes to immunology, vaccinology and brain development, degeneracy is a crucial part of how complex systems maintain their functional integrity. This review article discusses how the scientific concept of degeneracy was imported into genetics from physics and was later introduced to immunology and neuroscience. Using examples of degeneracy in immunology, neuroscience and linguistics, we demonstrate that degeneracy is a useful way of understanding how complex systems function. Reviewing the history and theoretical scope of degeneracy allows its usefulness to be better appreciated, its coherency to be further developed, and its application to be more quickly realized. PMID:25543071
Ultracold polar molecules near quantum degeneracy.
Ospelkaus, S; Ni, K K; de Miranda, M H G; Neyenhuis, B; Wang, D; Kotochigova, S; Julienne, P S; Jin, D S; Ye, J
2009-01-01
We report the creation and characterization of a near quantum-degenerate gas of polar 40K-87Rb molecules in their absolute rovibrational ground state. Starting from weakly bound heteronuclear KRb Feshbach molecules, we implement precise control of the molecular electronic, vibrational, and rotational degrees of freedom with phase-coherent laser fields. In particular, we coherently transfer these weakly bound molecules across a 125 THz frequency gap in a single step into the absolute rovibrational ground state of the electronic ground potential. Phase coherence between lasers involved in the transfer process is ensured by referencing the lasers to two single components of a phase-stabilized optical frequency comb. Using these methods, we prepare a dense gas of 4 x 10(4) polar molecules at a temperature below 400 nK. This fermionic molecular ensemble is close to quantum degeneracy and can be characterized by a degeneracy parameter of T/T(F) = 3. We have measured the molecular polarizability in an optical dipole trap where the trap lifetime gives clues to interesting decay mechanisms. Given the large measured dipole moment of the KRb molecules of 0.5 Debye, the study of quantum degenerate molecular gases interacting via strong dipolar interactions is now within experimental reach. PACS numbers: 37.10.Mn, 37.10.Pq. PMID:20151553
Degeneracy and discreteness in cosmological model fitting
NASA Astrophysics Data System (ADS)
Teng, Huan-Yu; Huang, Yuan; Zhang, Tong-Jie
2016-03-01
We explore the problems of degeneracy and discreteness in the standard cosmological model (ΛCDM). We use the Observational Hubble Data (OHD) and the type Ia supernovae (SNe Ia) data to study this issue. In order to describe the discreteness in fitting of data, we define a factor G to test the influence from each single data point and analyze the goodness of G. Our results indicate that a higher absolute value of G shows a better capability of distinguishing models, which means the parameters are restricted into smaller confidence intervals with a larger figure of merit evaluation. Consequently, we claim that the factor G is an effective way of model differentiation when using different models to fit the observational data.
Defects and degeneracies in supersymmetry protected phases
NASA Astrophysics Data System (ADS)
Fokkema, Thessa; Schoutens, Kareljan
2015-08-01
We analyse a class of 1D lattice models, known as \\text{M}k models, which are characterised by an order-k clustering of spin-less fermions and by N}=2 lattice supersymmetry. Our main result is the identification of a class of (bulk or edge) defects, that are in one-to-one correspondence with so-called spin fields in a corresponding {Z}k parafermion CFT. In the gapped regime, injecting such defects leads to ground-state degeneracies that are protected by the supersymmetry. The defects, which are closely analogous to quasi-holes over the fermonic Read-Rezayi quantum Hall states, display characteristic fusion rules, which are of Ising type for k = 2 and of Fibonacci type for k = 3.
Neutrino degeneracy and cosmological nucleosynthesis, revisited
NASA Technical Reports Server (NTRS)
Olive, K. A.; Schramm, David N.; Thomas, D.; Walker, T. P.
1991-01-01
A reexamination of the effects of non-zero degeneracies on Big Bang Nucleosynthesis is made. As previously noted, non-trivial alterations of the standard model conclusions can be induced only if excess lepton numbers L sub i, comparable to photon number densities eta sub tau, are assumed (where eta sub tau is approx. 3 times 10(exp 9) eta sub b). Furthermore, the required lepton number densities (L sub i eta sub tau) must be different for upsilon sub e than for upsilon sub mu and epsilon sub tau. It is shown that this loophole in the standard model of nucleosynthesis is robust and will not vanish as abundance and reaction rate determinations improve. However, it is also argued that theoretically (L sub e) approx. (L sub mu) approx. (L sub tau) approx. eta sub b is much less than eta sub tau which would preclude this loophole in standard unified models.
Breaking a dark degeneracy with gravitational waves
NASA Astrophysics Data System (ADS)
Lombriser, Lucas; Taylor, Andy
2016-03-01
We identify a scalar-tensor model embedded in the Horndeski action whose cosmological background and linear scalar fluctuations are degenerate with the concordance cosmology. The model admits a self-accelerated background expansion at late times that is stable against perturbations with a sound speed attributed to the new field that is equal to the speed of light. While degenerate in scalar fluctuations, self-acceleration of the model implies a present cosmological tensor mode propagation at lesssim95 % of the speed of light with a damping of the wave amplitude that is gtrsim5 % less efficient than in general relativity. We show that these discrepancies are endemic to self-accelerated Horndeski theories with degenerate large-scale structure and are tested with measurements of gravitational waves emitted by events at cosmological distances. Hence, gravitational-wave cosmology breaks the dark degeneracy in observations of the large-scale structure between two fundamentally different explanations of cosmic acceleration—a cosmological constant and a scalar-tensor modification of gravity. The gravitational wave event GW150914 recently detected with the aLIGO instruments and its potential association with a weak short gamma-ray burst observed with the Fermi GBM experiment may have provided this crucial measurement.
Statistical description of the black hole degeneracy spectrum
Barbero G, J. Fernando; Villasenor, Eduardo J. S.
2011-05-15
We use mathematical methods based on generating functions to study the statistical properties of the black hole degeneracy spectrum in loop quantum gravity. In particular we will study the persistence of the observed effective quantization of the entropy as a function of the horizon area. We will show that this quantization disappears as the area increases despite the existence of black hole configurations with a large degeneracy. The methods that we describe here can be adapted to the study of the statistical properties of the black hole degeneracy spectrum for all the existing proposals to define black hole entropy in loop quantum gravity.
Challenges and recognizable patterns in the en-face OCT of the retina
NASA Astrophysics Data System (ADS)
Rosen, Richard B.; Podoleanu, Adrian G.; Rogers, John A.; Garcia, Patricia; Lydon, Chris; Dunne, Shane; Dobre, George M.; Cucu, Radu G.; Jackson, David A.; Gentile, Ronald C.; Rosenthal, Jeanne L.; Muldoon, Thomas; Walsh, Joseph B.; Orlock, Dennis A.; Fisher, Yale; Yannuzzi, Lawrence A.
2004-07-01
Using an advanced prototype of en-face OCT/cSLO instrument, an extensive array of clinic pathologies were studied including macular degeneration, central serous retinopathy (CSR), macular hole, macular pucker, cystoid macular edema (CME), diabetic maculopathy, and macular trauma. We report observation of reoccurring patterns in the en-face OCT images which could be identified with different diseases. Uniquely specific and reoccurring patterns could be characterized for macular hole ("Chrysanthemum flower"), CME ("Swiss cheese wheel"), Macular Pucker ("Star"), CSR ("Target") and RPE Detachment ("Ring of Light"). Other entities such as polypoidal choroidopathy and diabetic edema residues had easily recognizable features but were variable enough to defy specific descriptive comparison. To facilitate the interpretation of the en-face OCT images, a three dimensional interactive simulation was designed which allows the demonstration of characteristic features and artifacts encountered in the acquisition of transverse images.
NASA Astrophysics Data System (ADS)
Maev, R. Gr.; Bakulin, E. Yu.; Maeva, A.; Severin, F.
Biometrics is a rapidly evolving scientific and applied discipline that studies possible ways of personal identification by means of unique biological characteristics. Such identification is important in various situations requiring restricted access to certain areas, information and personal data and for cases of medical emergencies. A number of automated biometric techniques have been developed, including fingerprint, hand shape, eye and facial recognition, thermographic imaging, etc. All these techniques differ in the recognizable parameters, usability, accuracy and cost. Among these, fingerprint recognition stands alone since a very large database of fingerprints has already been acquired. Also, fingerprints are key evidence left at a crime scene and can be used to indentify suspects. Therefore, of all automated biometric techniques, especially in the field of law enforcement, fingerprint identification seems to be the most promising. We introduce a newer development of the ultrasonic fingerprint imaging. The proposed method obtains a scan only once and then varies the C-scan gate position and width to visualize acoustic reflections from any appropriate depth inside the skin. Also, B-scans and A-scans can be recreated from any position using such data array, which gives the control over the visualization options. By setting the C-scan gate deeper inside the skin, distribution of the sweat pores (which are located along the ridges) can be easily visualized. This distribution should be unique for each individual so this provides a means of personal identification, which is not affected by any changes (accidental or intentional) of the fingers' surface conditions. This paper discusses different setups, acoustic parameters of the system, signal and image processing options and possible ways of 3-dimentional visualization that could be used as a recognizable characteristic in biometric identification.
The degeneracy problem in non-canonical inflation
Easson, Damien A.; Powell, Brian A. E-mail: brian.powell007@gmail.com
2013-03-01
While attempting to connect inflationary theories to observational physics, a potential difficulty is the degeneracy problem: a single set of observables maps to a range of different inflaton potentials. Two important classes of models affected by the degeneracy problem are canonical and non-canonical models, the latter marked by the presence of a non-standard kinetic term that generates observables beyond the scalar and tensor two-point functions on CMB scales. The degeneracy problem is manifest when these distinguishing observables go undetected. We quantify the size of the resulting degeneracy in this case by studying the most well-motivated non-canonical theory having Dirac-Born-Infeld Lagrangian. Beyond the scalar and tensor two-point functions on CMB scales, we then consider the possible detection of equilateral non-Gaussianity at Planck-precision and a measurement of primordial gravitational waves from prospective space-based laser interferometers. The former detection breaks the degeneracy with canonical inflation but results in poor reconstruction prospects, while the latter measurement enables a determination of n{sub T} which, while not breaking the degeneracy, can be shown to greatly improve the non-canonical reconstruction.
Degeneracies in long-baseline neutrino experiments from nonstandard interactions
NASA Astrophysics Data System (ADS)
Liao, Jiajun; Marfatia, Danny; Whisnant, Kerry
2016-05-01
We study parameter degeneracies that can occur in long-baseline neutrino appearance experiments due to nonstandard interactions (NSI) in neutrino propagation. For a single off-diagonal NSI parameter, and neutrino and antineutrino measurements at a single L /E , there exists a continuous four-fold degeneracy (related to the mass hierarchy and θ23 octant) that renders the mass hierarchy, octant, and C P phase unknowable. Even with a combination of NO ν A and T2K data, which in principle can resolve the degeneracy, both NSI and the C P phase remain unconstrained because of experimental uncertainties. A wide-band beam experiment like DUNE will resolve this degeneracy if the nonzero off-diagonal NSI parameter is ɛe μ. If ɛe τ is nonzero, or the diagonal NSI parameter ɛe e is O (1 ), a wrong determination of the mass hierarchy and of C P violation can occur at DUNE. The octant degeneracy can be further complicated by ɛe τ, but is not affected by ɛe e.
Large degeneracy of excited hadrons and quark models
Bicudo, P.
2007-11-01
The pattern of a large approximate degeneracy of the excited hadron spectra (larger than the chiral restoration degeneracy) is present in the recent experimental report of Bugg. Here we try to model this degeneracy with state of the art quark models. We review how the Coulomb Gauge chiral invariant and confining Bethe-Salpeter equation simplifies in the case of very excited quark-antiquark mesons, including angular or radial excitations, to a Salpeter equation with an ultrarelativistic kinetic energy with the spin-independent part of the potential. The resulting meson spectrum is solved, and the excited chiral restoration is recovered, for all mesons with J>0. Applying the ultrarelativistic simplification to a linear equal-time potential, linear Regge trajectories are obtained, for both angular and radial excitations. The spectrum is also compared with the semiclassical Bohr-Sommerfeld quantization relation. However, the excited angular and radial spectra do not coincide exactly. We then search, with the classical Bertrand theorem, for central potentials producing always classical closed orbits with the ultrarelativistic kinetic energy. We find that no such potential exists, and this implies that no exact larger degeneracy can be obtained in our equal-time framework, with a single principal quantum number comparable to the nonrelativistic Coulomb or harmonic oscillator potentials. Nevertheless we find it plausible that the large experimental approximate degeneracy will be modeled in the future by quark models beyond the present state of the art.
ARCN1 Mutations Cause a Recognizable Craniofacial Syndrome Due to COPI-Mediated Transport Defects.
Izumi, Kosuke; Brett, Maggie; Nishi, Eriko; Drunat, Séverine; Tan, Ee-Shien; Fujiki, Katsunori; Lebon, Sophie; Cham, Breana; Masuda, Koji; Arakawa, Michiko; Jacquinet, Adeline; Yamazumi, Yusuke; Chen, Shu-Ting; Verloes, Alain; Okada, Yuki; Katou, Yuki; Nakamura, Tomohiko; Akiyama, Tetsu; Gressens, Pierre; Foo, Roger; Passemard, Sandrine; Tan, Ene-Choo; El Ghouzzi, Vincent; Shirahige, Katsuhiko
2016-08-01
Cellular homeostasis is maintained by the highly organized cooperation of intracellular trafficking systems, including COPI, COPII, and clathrin complexes. COPI is a coatomer protein complex responsible for intracellular protein transport between the endoplasmic reticulum and the Golgi apparatus. The importance of such intracellular transport mechanisms is underscored by the various disorders, including skeletal disorders such as cranio-lenticulo-sutural dysplasia and osteogenesis imperfect, caused by mutations in the COPII coatomer complex. In this article, we report a clinically recognizable craniofacial disorder characterized by facial dysmorphisms, severe micrognathia, rhizomelic shortening, microcephalic dwarfism, and mild developmental delay due to loss-of-function heterozygous mutations in ARCN1, which encodes the coatomer subunit delta of COPI. ARCN1 mutant cell lines were revealed to have endoplasmic reticulum stress, suggesting the involvement of ER stress response in the pathogenesis of this disorder. Given that ARCN1 deficiency causes defective type I collagen transport, reduction of collagen secretion represents the likely mechanism underlying the skeletal phenotype that characterizes this condition. Our findings demonstrate the importance of COPI-mediated transport in human development, including skeletogenesis and brain growth. PMID:27476655
An emerging, recognizable facial phenotype in association with mutations in GLI-similar 3 (GLIS3).
Dimitri, Paul; De Franco, Elisa; Habeb, Abdelhadi M; Gurbuz, Fatih; Moussa, Khairya; Taha, Doris; Wales, Jerry K H; Hogue, Jacob; Slavotinek, Anne; Shetty, Ambika; Balasubramanian, Meena
2016-07-01
Neonatal diabetes and hypothyroidism (NDH) syndrome was first described in 2003 in a consanguineous Saudi Arabian family where two out of four siblings were reported to have presented with proportionate IUGR, neonatal non-autoimmune diabetes mellitus, severe congenital hypothyroidism, cholestasis, congenital glaucoma, and polycystic kidneys. Liver disease progressed to hepatic fibrosis. The renal disease was characterized by enlarged kidneys and multiple small cysts with deficient cortico-medullary junction differentiation and normal kidney function. There was minor facial dysmorphism (depressed nasal bridge, large anterior fontanelle, long philtrum) reported but no facial photographs were published. Mutations in the transcription factor GLI-similar 3 (GLIS3) gene in the original family and two other families were subsequently reported in 2006. All affected individuals had neonatal diabetes, congenital hypothyroidism but glaucoma and liver and kidney involvement were less consistent features. Detailed descriptions of the facial dysmorphism have not been reported previously. In this report, we describe the common facial dysmorphism consisting of bilateral low-set ears, depressed nasal bridge with overhanging columella, elongated, upslanted palpebral fissures, persistent long philtrum with a thin vermilion border of the upper lip in a cohort of seven patients with GLIS3 mutations and report the emergence of a distinct, probably recognizable facial gestalt in this group which evolves with age. © 2016 Wiley Periodicals, Inc. PMID:27148679
Identification of a Recognizable Progressive Skeletal Dysplasia Caused by RSPRY1 Mutations
Faden, Maha; AlZahrani, Fatema; Mendoza-Londono, Roberto; Dupuis, Lucie; Hartley, Taila; Kannu, Peter; Raiman, Julian A.; Howard, Andrew; Qin, Wen; Tetreault, Martine; Xi, Joan Qiongchao; Al-Thamer, Imadeddin; Maas, Richard L.; Boycott, Kym; Alkuraya, Fowzan S.
2015-01-01
Skeletal dysplasias are highly variable Mendelian phenotypes. Molecular diagnosis of skeletal dysplasias is complicated by their extreme clinical and genetic heterogeneity. We describe a clinically recognizable autosomal-recessive disorder in four affected siblings from a consanguineous Saudi family, comprising progressive spondyloepimetaphyseal dysplasia, short stature, facial dysmorphism, short fourth metatarsals, and intellectual disability. Combined autozygome/exome analysis identified a homozygous frameshift mutation in RSPRY1 with resulting nonsense-mediated decay. Using a gene-centric “matchmaking” system, we were able to identify a Peruvian simplex case subject whose phenotype is strikingly similar to the original Saudi family and whose exome sequencing had revealed a likely pathogenic homozygous missense variant in the same gene. RSPRY1 encodes a hypothetical RING and SPRY domain-containing protein of unknown physiological function. However, we detect strong RSPRY1 protein localization in murine embryonic osteoblasts and periosteal cells during primary endochondral ossification, consistent with a role in bone development. This study highlights the role of gene-centric matchmaking tools to establish causal links to genes, especially for rare or previously undescribed clinical entities. PMID:26365341
Accidental degeneracy of double Dirac cones in a phononic crystal
Chen, Ze-Guo; Ni, Xu; Wu, Ying; He, Cheng; Sun, Xiao-Chen; Zheng, Li-Yang; Lu, Ming-Hui; Chen, Yan-Feng
2014-01-01
Artificial honeycomb lattices with Dirac cone dispersion provide a macroscopic platform to study the massless Dirac quasiparticles and their novel geometric phases. In this paper, a quadruple-degenerate state is achieved at the center of the Brillouin zone in a two-dimensional honeycomb lattice phononic crystal, which is a result of accidental degeneracy of two double-degenerate states. In the vicinity of the quadruple-degenerate state, the dispersion relation is linear. Such quadruple degeneracy is analyzed by rigorous representation theory of groups. Using method, a reduced Hamiltonian is obtained to describe the linear Dirac dispersion relations of this quadruple-degenerate state, which is well consistent with the simulation results. Near such accidental degeneracy, we observe some unique properties in wave propagating, such as defect-insensitive propagating character and the Talbot effect. PMID:24714512
Pervasive flexibility in living technologies through degeneracy-based design.
Whitacre, James; Bender, Axel
2013-01-01
The capacity to adapt can greatly influence the success of systems that need to compensate for damaged parts, learn how to achieve robust performance in new environments, or exploit novel opportunities that originate from new technological interfaces or emerging markets. Many of the conditions in which technology is required to adapt cannot be anticipated during its design stage, thus creating a challenge for the designer. Inspired by the study of a range of biological systems, we propose that degeneracy-the realization of multiple, functionally versatile components with contextually overlapping functional redundancy-will support adaptation in technologies, because it effects pervasive flexibility, evolutionary innovation, and homeostatic robustness. We provide examples of degeneracy in a number of rudimentary living technologies, from military sociotechnical systems to swarm robotics, and we present design principles-including shared protocols, loose regulatory coupling, and functional versatility-that allow degeneracy to arise in both biological and man-made systems. PMID:23834594
Robust Topological and Holographic Degeneracies of Classical Systems
NASA Astrophysics Data System (ADS)
Vaezi, Seyyed Mohammad Sadegh; Nussinov, Zohar; Ortiz, Gerardo
We challenge the hypothesis that the ground states of a physical system whose degeneracy depends on topology must necessarily realize topological quantum order and display non-local entanglement. To this end, we introduce and study a classical rendition of the Toric Code model embedded on Riemann surfaces of different genus numbers. We find that the minimal ground state degeneracy (and those of all levels) depends on the topology of the embedding surface alone. As the ground states of this classical system may be distinguished by local measurements, a characteristic of Landau orders, this example illustrates that topological degeneracy is not a sufficient condition for topological quantum order. This conclusion is generic and, as shown, it applies to many other models. We also demonstrate that in certain lattice realizations of these models, and other theories, one can find a ground state entropy that is ''holographic'', i.e., extensive in the system's boundary.
Reducing Degeneracy in Maximum Entropy Models of Networks
NASA Astrophysics Data System (ADS)
Horvát, Szabolcs; Czabarka, Éva; Toroczkai, Zoltán
2015-04-01
Based on Jaynes's maximum entropy principle, exponential random graphs provide a family of principled models that allow the prediction of network properties as constrained by empirical data (observables). However, their use is often hindered by the degeneracy problem characterized by spontaneous symmetry breaking, where predictions fail. Here we show that degeneracy appears when the corresponding density of states function is not log-concave, which is typically the consequence of nonlinear relationships between the constraining observables. Exploiting these nonlinear relationships here we propose a solution to the degeneracy problem for a large class of systems via transformations that render the density of states function log-concave. The effectiveness of the method is demonstrated on examples.
Degeneracy between warm and coupled cold dark matter: A clarifying note
NASA Astrophysics Data System (ADS)
Velten, Hermano; Borges, Humberto A.; Caramês, Thiago R. P.
2016-03-01
Wei et al. [Phys. Rev. D 88, 043510 (2013)] have proposed the existence of a cosmological degeneracy between warm dark matter (WDM), modified gravity and coupled cold dark matter (CDM) cosmologies at both the background expansion and the growth of density perturbation levels; i.e., corresponding cosmological data would not be able to differentiate such scenarios. Here, we will focus on the specific indistinguishability between warm dark matter plus cosmological constant (Λ ) and coupled scalar field CDM scenarios. Although the statement of Wei et al. is true for very specific conditions we present a more complete discussion on this issue and show in more detail that these models are indeed distinguishable. We show that the degeneracy breaks down since coupled models leave a specific signature in the redshift space distortion data which is absent in the uncoupled warm dark matter cosmologies. Furthermore, we complement our claim by providing the reasons which suggest that even at nonlinear level a breaking of such apparent equivalence is also expected.
Degeneracy of energy levels of pseudo-Gaussian oscillators
Iacob, Theodor-Felix; Iacob, Felix; Lute, Marina
2015-12-07
We study the main features of the isotropic radial pseudo-Gaussian oscillators spectral properties. This study is made upon the energy levels degeneracy with respect to orbital angular momentum quantum number. In a previous work [6] we have shown that the pseudo-Gaussian oscillators belong to the class of quasi-exactly solvable models and an exact solution has been found.
The simplicity of perfect atoms: Degeneracies in supersymmetric hydrogen
Rube, Tomas; Wacker, Jay G.
2011-06-07
In this study, supersymmetric QED hydrogen-like bound states are remarkably similar to nonsupersymmetric hydrogen, including an accidental degeneracy of the fine structure and is broken by the Lamb shift. This article classifies the states, calculates the leading order spectrum, and illustrates the results in several limits. The relation to other nonrelativistic bound states is explored.
The simplicity of perfect atoms: Degeneracies in supersymmetric hydrogen
Rube, Tomas; Wacker, Jay G.
2011-06-15
Supersymmetric QED hydrogen-like bound states are remarkably similar to nonsupersymmetric hydrogen, including an accidental degeneracy of the fine structure and is broken by the Lamb shift. This article classifies the states, calculates the leading order spectrum, and illustrates the results in several limits. The relation to other nonrelativistic bound states is explored.
Quantification of degeneracy in Hodgkin-Huxley neurons on Newman-Watts small world network.
Man, Menghua; Zhang, Ya; Ma, Guilei; Friston, Karl; Liu, Shanghe
2016-08-01
Degeneracy is a fundamental source of biological robustness, complexity and evolvability in many biological systems. However, degeneracy is often confused with redundancy. Furthermore, the quantification of degeneracy has not been addressed for realistic neuronal networks. The objective of this paper is to characterize degeneracy in neuronal network models via quantitative mathematic measures. Firstly, we establish Hodgkin-Huxley neuronal networks with Newman-Watts small world network architectures. Secondly, in order to calculate the degeneracy, redundancy and complexity in the ensuing networks, we use information entropy to quantify the information a neuronal response carries about the stimulus - and mutual information to measure the contribution of each subset of the neuronal network. Finally, we analyze the interdependency of degeneracy, redundancy and complexity - and how these three measures depend upon network architectures. Our results suggest that degeneracy can be applied to any neuronal network as a formal measure, and degeneracy is distinct from redundancy. Qualitatively degeneracy and complexity are more highly correlated over different network architectures, in comparison to redundancy. Quantitatively, the relationship between both degeneracy and redundancy depends on network coupling strength: both degeneracy and redundancy increase with complexity for small coupling strengths; however, as coupling strength increases, redundancy decreases with complexity (in contrast to degeneracy, which is relatively invariant). These results suggest that the degeneracy is a general topologic characteristic of neuronal networks, which could be applied quantitatively in neuroscience and connectomics. PMID:27155043
The Simplicity of Perfect Atoms: Degeneracies in Supersymmetric Hydrogen
Rube, Tomas; Wacker, Jay G.; /SLAC /Stanford U., ITP
2011-08-19
Supersymmetric QED hydrogen-like bound states are remarkably similar to non-supersymmetric hydrogen, including an accidental degeneracy of the fine structure and which is broken by the Lamb shift. This article classifies the states, calculates the leading order spectrum, and illustrates the results in several limits. The relation to other non-relativistic bound states is explored. Supersymmetric bound states provide a laboratory for studying dynamics in supersymmetric theories. Bound states like hydrogen provide a framework for understanding the qualitative dynamics of QCD mesons, a supersymmetric version of QED can provide a qualitative picture for the symmetries and states of superQCD mesons. Furthermore, recent interest in dark matter as a composite state, leads to asking how supersymmetry acts upon these composite states [4-7]. This article calculates the leading order corrections to a hydrogen-like atoms in an exactly supersymmetric version of QED. Much of the degeneracy is broken by the fine structure and a seminal calculation was performed in [1] for positronium, see [2] for an N = 2 version of positronium. Supersymmetric hydrogen is a similar except for the absence of annihilation diagrams, see [3] for an independent calculation. In the heavy proton mass limit, the supersymmetric interactions of the theory become irrelevant operators, suppressed by powers of the proton mass like the magnetic moment operator in QED and the fine structure is identical to the non-supersymmetric theory. This article finds that fine structure spectrum of supersymmetric spectrum of hydrogen has an accidental degeneracy which is exactly analogous to the accidental degeneracy of the l = 0 and l = 1 levels of the n = 2; j = 1/2 state of hydrogen. The supersymmetric version of the Lamb shift lifts the residual degeneracy and this article computes the logarithmically enhanced breaking.
2010-01-01
were no differences between groups regarding functional class, severity of mitral regurgitation, LV volumes, and LV systolic function. Conclusions MAD is a common finding in myxomatous mitral valve disease patients, easily recognizable by transthoracic echocardiography. It is more prevalent in women and often associated with chest pain. MAD significantly disturbs mitral annular function and when severe predicts the occurrence of NSVT. PMID:21143934
Oscillation degeneracy in non-standard neutrino interactions
NASA Astrophysics Data System (ADS)
Wright, Warren
2016-06-01
The standard theory describing neutrino oscillations only uses the interactions predicted by the Standard Model of particle physics. However, there is plenty of room for non-standard interactions (NSI) to exist. This is because extra interactions are allowed by experimental error bars and even expected at some level from effective theory arguments. This research is focused on examining the phenomenological consequences of the new physics of NSI at large atmospheric neutrino detectors like IceCube DeepCore. Of particular focus are the degeneracies between and within the standard neutrino oscillation parameters and the NSI parameters. These degeneracies will be explored both analytically and numerically, and strategies to lift them will also be discussed. This research is largely based on [1].
Topological entanglement entropy, ground state degeneracy and holography
NASA Astrophysics Data System (ADS)
Parnachev, Andrei; Poovuttikul, Napat
2015-10-01
Topological entanglement entropy, a measure of the long-ranged entanglement, is related to the degeneracy of the ground state on a higher genus surface. The exact relation depends on the details of the topological theory. We consider a class of holographic models where such relation might be similar to the one exhibited by Chern-Simons theory in a certain large N limit. Both the non-vanishing topological entanglement entropy and the ground state degeneracy in these holographic models are consequences of the topological Gauss-Bonnet term in the dual gravitational description. A soft wall holographic model of confinement is used to generate finite correlation length but keep the disk topology of the entangling surface in the bulk, necessary for nonvanishing topological entanglement entropy.
A quantum spin liquid with a large topological degeneracy
NASA Astrophysics Data System (ADS)
Tchernyshyov, Oleg; Wang, Haoyu; Wan, Yuan
We present a model of a quantum spin liquid in two dimensions with a large topological degeneracy. The model has spins of length S = 1 / 2 on sites of a triangular lattice interacting via a 6-spin term. As in models of Kitaev and Wen [1-3], elementary building blocks in our model are strings of several distinct types. Ends of these strings are elementary particles: 4 bosons and 3 fermions. Particles of different types are mutual semions. The degeneracy of the ground state on a torus is 2 7 - 1 = 64 . Elementary excitations of the model are boson-fermion pairs, which come in 3 × 4 = 12 distinct types Research funding comes from the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-FG02-08ER46544.
A backtracking algorithm that deals with particle filter degeneracy
NASA Astrophysics Data System (ADS)
Baarsma, Rein; Schmitz, Oliver; Karssenberg, Derek
2016-04-01
Particle filters are an excellent way to deal with stochastic models incorporating Bayesian data assimilation. While they are computationally demanding, the particle filter has no problem with nonlinearity and it accepts non-Gaussian observational data. In the geoscientific field it is this computational demand that creates a problem, since dynamic grid-based models are often already quite computationally demanding. As such it is of the utmost importance to keep the amount of samples in the filter as small as possible. Small sample populations often lead to filter degeneracy however, especially in models with high stochastic forcing. Filter degeneracy renders the sample population useless, as the population is no longer statistically informative. We have created an algorithm in an existing data assimilation framework that reacts to and deals with filter degeneracy based on Spiller et al. [2008]. During the Bayesian updating step of the standard particle filter, the algorithm tests the sample population for filter degeneracy. If filter degeneracy has occurred, the algorithm resets to the last time the filter did work correctly and recalculates the failed timespan of the filter with an increased sample population. The sample population is then reduced to its original size and the particle filter continues as normal. This algorithm was created in the PCRaster Python framework, an open source tool that enables spatio-temporal forward modelling in Python [Karssenberg et al., 2010] . The framework already contains several data assimilation algorithms, including a standard particle filter and a Kalman filter. The backtracking particle filter algorithm has been added to the framework, which will make it easy to implement in other research. The performance of the backtracking particle filter is tested against a standard particle filter using two models. The first is a simple nonlinear point model, and the second is a more complex geophysical model. The main testing
32 CFR 720.10 - Members released by civil authorities on bail or on their own recognizance.
Code of Federal Regulations, 2010 CFR
2010-07-01
... absence, shall grant liberty or leave to permit appearance for trial, unless this would have a serious negative impact on the command. In the event that liberty or leave is not granted, a judge advocate of...
32 CFR 720.10 - Members released by civil authorities on bail or on their own recognizance.
Code of Federal Regulations, 2011 CFR
2011-07-01
... absence, shall grant liberty or leave to permit appearance for trial, unless this would have a serious negative impact on the command. In the event that liberty or leave is not granted, a judge advocate of...
Ultra-broad bandwidth parametric amplification at degeneracy.
Limpert, J; Aguergaray, C; Montant, S; Manek-Hönninger, I; Petit, S; Descamps, D; Cormier, E; Salin, F
2005-09-19
We report on a novel approach of ultra-broad bandwidth parametric amplification around degeneracy. A bandwidth of up to 400 nm centered around 800 nm is amplified in a BBO crystal by using chirped pump pulses with a bandwitdth as broad as 10 nm. A supercontinuum signal is generated in a microstructured fiber, having to first order a quadratic chirp, which is necessary to ensure temporal overlap of the interacting waves over this broad bandwidth. Furthermore, we discuss the potential of this approach for an octave-spanning parametric amplification. PMID:19498762
On uniqueness and non-degeneracy of anisotropic polarons
NASA Astrophysics Data System (ADS)
Ricaud, Julien
2016-05-01
We study the anisotropic Choquard-Pekar equation which describes a polaron in an anisotropic medium. We prove the uniqueness and non-degeneracy of minimizers in a weakly anisotropic medium. In addition, for a wide range of anisotropic media, we derive the symmetry properties of minimizers and prove that the kernel of the associated linearized operator is reduced, apart from three functions coming from the translation invariance, to the kernel on the subspace of functions that are even in each of the three principal directions of the medium.
Large and exact quantum degeneracy in a skyrmion magnet
NASA Astrophysics Data System (ADS)
Douçot, B.; Kovrizhin, D. L.; Moessner, R.
2016-03-01
We identify a large family of ground states of a topological C PN -1 skyrmion magnet whose classical degeneracy persists to all orders in a semiclassical expansion. This goes along with an exceptional robustness of the concomitant ground-state configurations, which are not at all dressed by quantum fluctuations. We trace these twin observations back to a common root: this class of topological ground states saturates a Bogomolny inequality. A similar phenomenology occurs in high-energy physics for some field theories exhibiting supersymmetry. We propose quantum Hall ferromagnets, where these skyrmions configurations arise naturally as ground states away from integer filling, as the best available laboratory realisations.
Degeneracy allows for both apparent homogeneity and diversification in populations
Whitacre, James M.; Atamas, Sergei P.
2013-01-01
Trait diversity – the substrate for natural selection – is necessary for adaptation through selection, particularly in populations faced with environmental changes that diminish population fitness. In habitats that remain unchanged for many generations, stabilizing selection maximizes exploitation of resources by reducing trait diversity to a narrow optimal range. One might expect that such ostensibly homogeneous populations would have a reduced potential for heritable adaptive responses when faced with fitness-reducing environmental changes. However, field studies have documented populations that, even after long periods of evolutionary stasis, can still rapidly evolve in response to changed environmental conditions. We argue that degeneracy, the ability of diverse population elements to function similarly, can satisfy both the current need to maximize fitness and the future need for diversity. Degenerate ensembles appear functionally redundant in certain environmental contexts and functionally diverse in others. We propose that genetic variation not contributing to the observed range of phenotypes in a current population, also known as cryptic genetic variation (CGV), is a specific case of degeneracy. We argue that CGV, which gradually accumulates in static populations in stable environments, reveals hidden trait differences when environments change. By allowing CGV accumulation, static populations prepare themselves for future rapid adaptations to environmental novelty. A greater appreciation of degeneracy’s role in resolving the inherent tension between current stabilizing selection and future directional selection has implications in conservation biology and may be applied in social and technological systems to maximize current performance while strengthening the potential for future changes. PMID:22910487
Degeneracy, frequency response and filtering in IMRT optimization
NASA Astrophysics Data System (ADS)
Llacer, Jorge; Agazaryan, Nzhde; Solberg, Timothy D.; Promberger, Claus
2004-07-01
This paper attempts to provide an answer to some questions that remain either poorly understood, or not well documented in the literature, on basic issues related to intensity modulated radiation therapy (IMRT). The questions examined are: the relationship between degeneracy and frequency response of optimizations, effects of initial beamlet fluence assignment and stopping point, what does filtering of an optimized beamlet map actually do and how could image analysis help to obtain better optimizations? Two target functions are studied, a quadratic cost function and the log likelihood function of the dynamically penalized likelihood (DPL) algorithm. The algorithms used are the conjugate gradient, the stochastic adaptive simulated annealing and the DPL. One simple phantom is used to show the development of the analysis tools used and two clinical cases of medium and large dose matrix size (a meningioma and a prostate) are studied in detail. The conclusions reached are that the high number of iterations that is needed to avoid degeneracy is not warranted in clinical practice, as the quality of the optimizations, as judged by the DVHs and dose distributions obtained, does not improve significantly after a certain point. It is also shown that the optimum initial beamlet fluence assignment for analytical iterative algorithms is a uniform distribution, but such an assignment does not help a stochastic method of optimization. Stopping points for the studied algorithms are discussed and the deterioration of DVH characteristics with filtering is shown to be partially recoverable by the use of space-variant filtering techniques.
Epigenomics and the concept of degeneracy in biological systems
Mason, Paul H.; Barron, Andrew B.
2014-01-01
Researchers in the field of epigenomics are developing more nuanced understandings of biological complexity, and exploring the multiple pathways that lead to phenotypic expression. The concept of degeneracy—referring to the multiple pathways that a system recruits to achieve functional plasticity—is an important conceptual accompaniment to the growing body of knowledge in epigenomics. Distinct from degradation, redundancy and dilapidation; degeneracy refers to the plasticity of traits whose function overlaps in some environments, but diverges in others. While a redundant system is composed of repeated identical elements performing the same function, a degenerate system is composed of different elements performing similar or overlapping functions. Here, we describe the degenerate structure of gene regulatory systems from the basic genetic code to flexible epigenomic modifications, and discuss how these structural features have contributed to organism complexity, robustness, plasticity and evolvability. PMID:24335757
Valley degeneracy in biaxially strained aluminum arsenide quantum wells
NASA Astrophysics Data System (ADS)
Prabhu-Gaunkar, S.; Birner, S.; Dasgupta, S.; Knaak, C.; Grayson, M.
2011-09-01
This paper describes a complete analytical formalism for calculating electron subband energy and degeneracy in strained multivalley quantum wells grown along any orientation with explicit results for AlAs quantum wells (QWs). In analogy to the spin index, the valley degree of freedom is justified as a pseudospin index due to the vanishing intervalley exchange integral. A standardized coordinate transformation matrix is defined to transform between the conventional-cubic-cell basis and the QW transport basis whereby effective mass tensors, valley vectors, strain matrices, anisotropic strain ratios, piezoelectric fields, and scattering vectors are all defined in their respective bases. The specific cases of (001)-, (110)-, and (111)-oriented aluminum arsenide (AlAs) QWs are examined, as is the unconventional (411) facet, which is of particular importance in AlAs literature. Calculations of electron confinement and strain for the (001), (110), and (411) facets determine the critical well width for crossover from double- to single-valley degeneracy in each system. The biaxial Poisson ratio is calculated for the high-symmetry lower Miller index (001)-, (110)-, and (111)-oriented QWs. An additional shear-strain component arises in the higher Miller index (411)-oriented QWs and we define and solve for a shear-to-biaxial strain ratio. The notation is generalized to address non-Miller-indexed planes so that miscut substrates can also be treated, and the treatment can be adapted to other multivalley biaxially strained systems. To help classify anisotropic intervalley scattering, a valley scattering primitive unit cell is defined in momentum space, which allows one to distinguish purely in-plane momentum scattering events from those that require an out-of-plane momentum component.
Frauscher, Birgit; Mitterling, Thomas; Bode, Aleke; Ehrmann, Laura; Gabelia, David; Biermayr, Marlene; Walters, Arthur Scott; Poewe, Werner; Högl, Birgit
2014-01-01
Study Objectives: Despite several polysomnographic normative studies and multiple surveys of sleep disorders in the general population, few data have been collected on healthy sleepers. We aimed to survey the characteristics of healthy sleep. Methods: We prospectively investigated the sleep history of 100 subjects of a representative population sample who reported undisturbed sleep and in whom relevant sleep disorders were ruled out by a two-step screening procedure. Approximately four subjects had to be contacted for identifying 1 eligible subject who participated. Results: The median reported time in bed was from 23:00 (21:30–02:00) to 07:00 (05:30–11:00). The total sleep duration was 7.3 h (5–10 h), varying from 7.5 h in the age group ≤ 30 years to 7 h in subjects aged 40–60 years and to 8 h in subjects > 60 years (p = 0.002). The median sleep efficiency was high (93.3%, range: 55.6% to 100%). Fifty-one subjects reported occasional snoring. Forty-five subjects reported sporadic non-bothersome sleep-related movement disorders (25 sleep-related leg cramps, 22 lifetime bruxism, 5 restless legs syndrome), and 36 had a history of sporadic non-bothersome parasomnias (27 nightmares, 12 sleepwalking, 1 sleep paralysis). Conclusion: In this population of healthy sleepers, snoring is the most common finding. Moreover, non-bothersome forms of recognizable sleep-related movement disorders and parasomnias are surprisingly common. These findings may suggest that diagnostic criteria of sleep disorders should not only be based on the presence of symptoms but also account for a minimum frequency or discomfort. Citation: Frauscher B, Mitterling T, Bode A, Ehrmann L, Gabelia D, Biermayr M, Walters AS, Poewe W, Högl B. A prospective questionnaire study in 100 healthy sleepers: non-bothersome forms of recognizable sleep disorders are still present. J Clin Sleep Med 2014;10(6):623-629. PMID:24932141
Geneugelijk, K; Hönger, G; van Deutekom, H W M; Thus, K A; Keşmir, C; Hösli, I; Schaub, S; Spierings, E
2015-12-01
Pregnancy can prime maternal immune responses against inherited paternal HLA of the fetus, leading to the production of child-specific HLA antibodies. We previously demonstrated that donor-specific HLA antibody formation after kidney transplantation is associated with donor-derived HLA epitopes presented by recipient HLA class II (predicted indirectly recognizable HLA epitopes presented by HLA class II [PIRCHE-II]). In the present study, we evaluated the role of PIRCHE-II in child-specific HLA antibody formation during pregnancy. A total of 229 mother-child pairs were HLA typed. For all mismatched HLA class I molecules of the child, we subsequently predicted the number of HLA epitopes that could be presented by maternal HLA class II molecules. Child-specific antigens were classified as either immunogenic or nonimmunogenic HLA based on the presence of specific antibodies and correlated to PIRCHE-II numbers. Immunogenic HLA contained higher PIRCHE-II numbers than nonimmunogenic HLA. Moreover, the probability of antibody production during pregnancy increased with the number of PIRCHE-II. In conclusion, our data suggest that the number of PIRCHE-II is related to the formation of child-specific HLA antibodies during pregnancy. Present confirmation of the role of PIRCHE-II in antibody formation outside the transplantation setting suggests the PIRCHE-II concept is universal. PMID:26512793
CMB power spectrum parameter degeneracies in the era of precision cosmology
Howlett, Cullan; Lewis, Antony; Hall, Alex; Challinor, Anthony E-mail: antony@cosmologist.info E-mail: adc1000@ast.cam.ac.uk
2012-04-01
Cosmological parameter constraints from the CMB power spectra alone suffer several well-known degeneracies. These degeneracies can be broken by numerical artefacts and also a variety of physical effects that become quantitatively important with high-accuracy data e.g. from the Planck satellite. We study degeneracies in models with flat and non-flat spatial sections, non-trivial dark energy and massive neutrinos, and investigate the importance of various physical degeneracy-breaking effects. We test the CAMB power spectrum code for numerical accuracy, and demonstrate that the numerical calculations are accurate enough for degeneracies to be broken mainly by true physical effects (the integrated Sachs-Wolfe effect, CMB lensing and geometrical and other effects through recombination) rather than numerical artefacts. We quantify the impact of CMB lensing on the power spectra, which inevitably provides degeneracy-breaking information even without using information in the non-Gaussianity. Finally we check the numerical accuracy of sample-based parameter constraints using CAMB and COSMOMC. In an appendix we document recent changes to CAMB's numerical treatment of massive neutrino perturbations, which are tested along with other recent improvements by our degeneracy exploration results.
Degeneracy, degree, and heavy tails in quantum annealing
NASA Astrophysics Data System (ADS)
King, Andrew D.; Hoskinson, Emile; Lanting, Trevor; Andriyash, Evgeny; Amin, Mohammad H.
2016-05-01
Both simulated quantum annealing and physical quantum annealing have shown the emergence of "heavy tails" in their performance as optimizers: The total time needed to solve a set of random input instances is dominated by a small number of very hard instances. Classical simulated annealing, in contrast, does not show such heavy tails. Here we explore the origin of these heavy tails, which appear for inputs with high local degeneracy—large isoenergetic clusters of states in Hamming space. This category includes the low-precision Chimera-structured problems studied in recent benchmarking work comparing the D-Wave Two quantum annealing processor with simulated annealing. On similar inputs designed to suppress local degeneracy, performance of a quantum annealing processor on hard instances improves by orders of magnitude at the 512-qubit scale, while classical performance remains relatively unchanged. Simulations indicate that perturbative crossings are the primary factor contributing to these heavy tails, while sensitivity to Hamiltonian misspecification error plays a less significant role in this particular setting.
Dynamics versus structure: breaking the density degeneracy in star formation
NASA Astrophysics Data System (ADS)
Parker, Richard J.
2014-12-01
The initial density of individual star-forming regions (and by extension the birth environment of planetary systems) is difficult to constrain due to the `density degeneracy problem': an initially dense region expands faster than a more quiescent region due to two-body relaxation and so two regions with the same observed present-day density may have had very different initial densities. We constrain the initial densities of seven nearby star-forming regions by folding in information on their spatial structure from the {Q}-parameter and comparing the structure and present-day density to the results of N-body simulations. This in turn places strong constraints on the possible effects of dynamical interactions and radiation fields from massive stars on multiple systems and protoplanetary discs. We apply our method to constrain the initial binary population in each of these seven regions and show that the populations in only three - the Orion Nebula Cluster, ρ Oph, and Corona Australis - are consistent with having evolved from the Kroupa universal initial period distribution and a binary fraction of unity.
Electronic orders in multiorbital Hubbard models with lifted orbital degeneracy
NASA Astrophysics Data System (ADS)
Hoshino, Shintaro; Werner, Philipp
2016-04-01
We study the symmetry-broken phases in two- and three-orbital Hubbard models with lifted orbital degeneracy using dynamical mean-field theory. On the technical level, we explain how symmetry relations can be exploited to measure the four-point correlation functions needed for the calculation of the lattice susceptibilities. In the half-filled two-orbital model with crystal-field splitting, we find an instability of the metallic phase to spin-orbital order with neither spin nor orbital moment. This ordered phase is shown to be related to the recently discovered fluctuating-moment induced spin-triplet superconducting state in the orbitally degenerate model with shifted chemical potential. In the three-orbital case, we consider the effect of a crystal-field splitting on the spin-triplet superconducting state in the model with positive Hund coupling, and the spin-singlet superconducting state in the case of negative Hund coupling. It is demonstrated that for certain crystal-field splittings the higher energy orbitals instead of the lower ones are relevant for superconductivity, and that Tc can be slightly enhanced by the crystal-field effect. We comment on the implications of our results for the superconductivity in strontium ruthenates, and for the recently reported light-enhanced superconducting state in alkali-metal-doped fullerides.
NASA Astrophysics Data System (ADS)
Tallents, G. J.
2016-09-01
Collisional-radiative models enable average ionization and ionization populations, plus the rates of absorption and emission of radiation to be calculated for plasmas not in thermal equilbrium. At high densities and low temperatures, electrons may have a high occupancy of the free electron quantum states and evaluations of rate coefficients need to take into account the free electron degeneracy. We demonstrate that electron degeneracy can reduce collisional rate coefficients by orders-of-magnitude from values calculated neglecting degeneracy. We show that assumptions regarding the collisional differential cross-section can alter collisional ionization and recombination rate coefficients by a further factor two under conditions relevant to inertial fusion.
Amouroux, Cyril; Vincent, Marie; Blanchet, Patricia; Puechberty, Jacques; Schneider, Anouck; Chaze, Anne Marie; Girard, Manon; Tournaire, Magali; Jorgensen, Christian; Morin, Denis; Sarda, Pierre; Lefort, Geneviève; Geneviève, David
2012-01-01
Duane retraction syndrome (DRS) is a rare congenital strabismus condition with genetic heterogeneity. DRS associated with intellectual disability or developmental delay is observed in several genetic diseases: syndromes such as Goldenhar or Wildervanck syndrome and chromosomal anomalies such as 12q12 deletion. We report on the case of a patient with DRS, developmental delay and particular facial features (horizontal and flared eyebrows, long and smooth philtrum, thin upper lip, full lower lip and full cheeks). We identified a duplication of the long arm of chromosome 8 (8q12) with SNP-array. This is the third case of a patient with common clinical features and 8q12 duplication described in the literature. The minimal critical region is 1.2 Mb and encompasses four genes: CA8, RAB2, RLBP1L1 and CHD7. To our knowledge, no information is available in the literature regarding pathological effects caused by to overexpression of these genes. However, loss of function of the CHD7 gene leads to CHARGE syndrome, suggesting a possible role of the overexpression of this gene in the phenotype observed in 8q12 duplication patients. We have observed that patients with 8q12 duplication share a common recognizable phenotype characterized by DRS, developmental delay and facial features. Such data combined to the literature strongly suggest that this entity may define a novel syndrome. We hypothesize that CHD7 duplication is responsible for a part of the features observed in 8q12.2 duplication. PMID:22258531
Lugtenberg, Dorien; Reijnders, Margot R F; Fenckova, Michaela; Bijlsma, Emilia K; Bernier, Raphael; van Bon, Bregje W M; Smeets, Eric; Vulto-van Silfhout, Anneke T; Bosch, Danielle; Eichler, Evan E; Mefford, Heather C; Carvill, Gemma L; Bongers, Ernie M H F; Schuurs-Hoeijmakers, Janneke Hm; Ruivenkamp, Claudia A; Santen, Gijs W E; van den Maagdenberg, Arn M J M; Peeters-Scholte, Cacha M P C D; Kuenen, Sabine; Verstreken, Patrik; Pfundt, Rolph; Yntema, Helger G; de Vries, Petra F; Veltman, Joris A; Hoischen, Alexander; Gilissen, Christian; de Vries, Bert B A; Schenck, Annette; Kleefstra, Tjitske; Vissers, Lisenka E L M
2016-08-01
Recently WAC was reported as a candidate gene for intellectual disability (ID) based on the identification of a de novo mutation in an individual with severe ID. WAC regulates transcription-coupled histone H2B ubiquitination and has previously been implicated in the 10p12p11 contiguous gene deletion syndrome. In this study, we report on 10 individuals with de novo WAC mutations which we identified through routine (diagnostic) exome sequencing and targeted resequencing of WAC in 2326 individuals with unexplained ID. All but one mutation was expected to lead to a loss-of-function of WAC. Clinical evaluation of all individuals revealed phenotypic overlap for mild ID, hypotonia, behavioral problems and distinctive facial dysmorphisms, including a square-shaped face, deep set eyes, long palpebral fissures, and a broad mouth and chin. These clinical features were also previously reported in individuals with 10p12p11 microdeletion syndrome. To investigate the role of WAC in ID, we studied the importance of the Drosophila WAC orthologue (CG8949) in habituation, a non-associative learning paradigm. Neuronal knockdown of Drosophila CG8949 resulted in impaired learning, suggesting that WAC is required in neurons for normal cognitive performance. In conclusion, we defined a clinically recognizable ID syndrome, caused by de novo loss-of-function mutations in WAC. Independent functional evidence in Drosophila further supported the role of WAC in ID. On the basis of our data WAC can be added to the list of ID genes with a role in transcription regulation through histone modification. PMID:26757981
Ji, Jianling; Lee, Hane; Argiropoulos, Bob; Dorrani, Naghmeh; Mann, John; Martinez-Agosto, Julian A; Gomez-Ospina, Natalia; Gallant, Natalie; Bernstein, Jonathan A; Hudgins, Louanne; Slattery, Leah; Isidor, Bertrand; Le Caignec, Cédric; David, Albert; Obersztyn, Ewa; Wiśniowiecka-Kowalnik, Barbara; Fox, Michelle; Deignan, Joshua L; Vilain, Eric; Hendricks, Emily; Horton Harr, Margaret; Noon, Sarah E; Jackson, Jessi R; Wilkens, Alisha; Mirzaa, Ghayda; Salamon, Noriko; Abramson, Jeff; Zackai, Elaine H; Krantz, Ian; Innes, A Micheil; Nelson, Stanley F; Grody, Wayne W; Quintero-Rivera, Fabiola
2015-11-01
Dual-specificity tyrosine-(Y)-phosphorylation-regulated kinase 1 A (DYRK1A ) is a highly conserved gene located in the Down syndrome critical region. It has an important role in early development and regulation of neuronal proliferation. Microdeletions of chromosome 21q22.12q22.3 that include DYRK1A (21q22.13) are rare and only a few pathogenic single-nucleotide variants (SNVs) in the DYRK1A gene have been described, so as of yet, the landscape of DYRK1A disruptions and their associated phenotype has not been fully explored. We have identified 14 individuals with de novo heterozygous variants of DYRK1A; five with microdeletions, three with small insertions or deletions (INDELs) and six with deleterious SNVs. The analysis of our cohort and comparison with published cases reveals that phenotypes are consistent among individuals with the 21q22.12q22.3 microdeletion and those with translocation, SNVs, or INDELs within DYRK1A. All individuals shared congenital microcephaly at birth, intellectual disability, developmental delay, severe speech impairment, short stature, and distinct facial features. The severity of the microcephaly varied from -2 SD to -5 SD. Seizures, structural brain abnormalities, eye defects, ataxia/broad-based gait, intrauterine growth restriction, minor skeletal abnormalities, and feeding difficulties were present in two-thirds of all affected individuals. Our study demonstrates that haploinsufficiency of DYRK1A results in a new recognizable syndrome, which should be considered in individuals with Angelman syndrome-like features and distinct facial features. Our report represents the largest cohort of individuals with DYRK1A disruptions to date, and is the first attempt to define consistent genotype-phenotype correlations among subjects with 21q22.13 microdeletions and DYRK1A SNVs or small INDELs. PMID:25944381
Linear electronic transport in dense plasmas. II. Finite degeneracy contributions
NASA Astrophysics Data System (ADS)
Léger, D.; Deutsch, C.
1991-06-01
The formalism described in the first paper in this series is hereafter specialized to a thorough investigation of finite degeneracy contributions to thermoelectronic and mechanical transport coefficients, conveniently expressed as reduced quantities. Temperature corrections are systematically discussed through the analytical properties of the jellium dielectric function. The Thomas-Fermi one appears as a paradigm of regular behavior at q=2k_F while the Lindhard and its T-dependent extension head a singular class characterized by diverging derivatives. Specific methods are developed for these important cases. Results are presented in terms of analytic expansions in the degeneracy parameter α, and exact expressions for the above-mentioned corrections are derived up to order α2. Finally we display a number of numerical results pertaining to fully ionized proton-helium binary mixtures of Astrophysical interest. The connection of the present formalism and its numerical outputs with other previous treatments is also carefully examined. Le formalisme exposé et détaillé dans le premier article de cette série est ici appliqué à la détermination des contributions de dégénérescence partielle aux coefficients de transport thermoélectroniques et mécanique (viscosité), coefficients préalablement exprimés sous forme d'expressions réduites. Les corrections de température finie sont systématiquement analysées en relation avec les propriétés analytiques de la fonction diélectrique du jellium. Alors que celle de Thomas-Fermi fournit l'exemple type de fonction parfaitement régulière en q=2k_F, celle de Lindhard et sa généralisation à T finie sont au contraire caractérisées par des dérivées divergentes en ce point. Des méthodes spécifiques sont développées pour traiter correctement ces cas importants. Nos résultats sont présentés sous forme de développements analytiques en puissance du paramètre de dégénérescence α, et des expressions
Quantum degeneracy corrections to plasma line emission and to Saha equation
NASA Astrophysics Data System (ADS)
Molinari, V. G.; Mostacci, D.; Rocchi, F.; Sumini, M.
2003-09-01
The effect of quantum degeneracy on the electron collisional excitation is investigated, and its effects on line emission evaluated for applications to spectroscopy of dense, cold plasmas. A correction to Saha equation for weakly-degenerate plasmas is also presented.
Degeneracy between mass and spin in black-hole-binary waveforms
NASA Astrophysics Data System (ADS)
Baird, Emily; Fairhurst, Stephen; Hannam, Mark; Murphy, Patricia
2013-01-01
We explore the degeneracy between mass and spin in gravitational waveforms emitted by black-hole-binary coalescences. We focus on spin-aligned waveforms and obtain our results using phenomenological models that were tuned to numerical-relativity simulations. A degeneracy is known for low-mass binaries (particularly neutron-star binaries), where gravitational-wave detectors are sensitive to only the inspiral phase, and the waveform can be modeled by post-Newtonian theory. Here, we consider black-hole binaries, where detectors will also be sensitive to the merger and ringdown, and demonstrate that the degeneracy persists across a broad mass range. At low masses, the degeneracy is between mass ratio and the black-hole spins, with chirp mass accurately determined. At higher masses, the degeneracy persists but is not so clearly characterized by constant chirp mass as the merger and ringdown become more significant. We consider the importance of this degeneracy both for performing searches (including searches where only nonspinning templates are used) and in parameter extraction from observed systems. We compare observational capabilities between the early (˜2015) and final (2018 onwards) versions of the Advanced LIGO detector.
The effect of degeneracy parameter on Weibel instability in dense plasma
Mahdavi, M.; Khodadadi Azadboni, F.
2013-12-15
In this paper, the role of degeneracy parameter, in both directions parallel and perpendicular with propagation direction of the laser beam in plasma, on the growth rate of Weibel instability, is studied. Calculations show that with the temperature anisotropy, β = T{sub ∥}/T{sub ⊥} = 0.2 and a 0.75 times reduction of the degeneracy parameter, the increased rate of the the Weibel instability growth rate is 72%. The degeneracy required for minimal growth rate in interaction laser plasma with a density of 1.2 × 10{sup 32}m{sup −3}, is larger than 3. The reduction of temperature and the degeneracy parameter of plasma in parallel direction will also increase growth rate about 30% more than incrossing degeneracy parameter in transverse direction. With the minimum pressure costs of cold compression, subsequent degeneracy parameters, and the minimum value of electron quiver energy, we can expect growth rate of Weibel instability order 0.01.
Parameter degeneracy in neutrino oscillation — Solution network and structural overview
NASA Astrophysics Data System (ADS)
Minakata, Hisakazu; Uchinami, Shoichi
2010-04-01
It is known that there is a phenomenon called “parameter degeneracy” in neutrino oscillation measurement of lepton mixing parameters; A set of the oscillation probabilities, e.g., P( ν μ → ν e ) and its CP-conjugate Pleft( {{{bar ν }_μ } to {{bar ν }_e}} right) at a particular neutrino energy does not determine uniquely the values of θ 13 and δ. With use of the approximate form of the oscillation probability á la Cervera et al., a complete analysis of the eightfold parameter degeneracy is presented. We propose a unified view of the various types of the degeneracy as invariance of the oscillation probabilities under discrete mappings of the mixing parameters. Explicit form of the mapping is obtained either by symmetry argument, or by deriving exact analytic expressions of all the degeneracy solutions for a given true solution. Due to the one-to-one mapping structure the degeneracy solutions are shown to form a network. We extend our analysis into the parameter degeneracy in T- and CPT-conjugate measurement as well as to the setup with the golden and the silver channels, P( ν e → ν μ ) and P( ν e → ν τ ). Some characteristic features of the degeneracy solutions in CP-conjugate measurement, in particular their energy dependences, are illuminated by utilizing the explicit analytic solutions.
A new method to break the mass sheet degeneracy using aperture moments
NASA Astrophysics Data System (ADS)
Rexroth, Markus; Natarajan, Priyamvada; Kneib, Jean-Paul
2016-04-01
Mass determinations from gravitational lensing shear and the higher order estimator flexion are both subject to the mass sheet degeneracy. Mass sheet degeneracy refers to the ambiguity that arises due to the fact that the addition of a constant surface mass density sheet does not alter the lensing observables. We propose a new technique to break the mass sheet degeneracy. The method uses mass moments of the shear or flexion fields in combination with convergence information derived from number counts which exploit the magnification bias. The difference between the measured mass moments provides an estimator for the magnitude of the additive constant that is the mass-sheet. For demonstrating this, we derive relations that hold true in general for n-th order moments and show how they can be employed effectively to break the degeneracy. We investigate the detectability of this degeneracy parameter from our method and find that the degeneracy parameter can be feasibly determined from stacked galaxy-galaxy lensing data and cluster lensing data. Furthermore, we compare the signal-to-noise ratios of convergence information from number counts with shear and flexion for SIS and NFW models. We find that the combination of shear and flexion performs best on galaxy and cluster scales and the convergence information can therefore be used to break the mass sheet degeneracy without quality loss in the mass reconstruction. In summary, there is power in the combination of shear, flexion, convergence and their higher order moments. With the anticipated wealth of lensing data from upcoming and future satellite missions - EUCLID and WFIRST - this technique will be feasible.
Degeneracy in NLP and the development of results motivated by its presence
Fiacco, A.; Liu, J.
1994-12-31
We study notions of nondegeneracy and several levels of increasing degeneracy from the perspective of the local behavior of a local solution of a nonlinear program when problem parameters are slightly perturbed. This overview may be viewed as a structured survey of sensitivity and stability results: the focus is on progressive levels of degeneracy. We note connections of nondegeneracy with the convergence of algorithms and observe the striking parallel between the effects of nondegeneracy and degeneracy on optimality conditions, stability analysis and algorithmic convergence behavior. Although our orientation here is primarily interpretive and noncritical, we conclude that more effort is needed to unify optimality, stability and convergence theory and more results are needed in all three areas for radically degenerate problems.
Taraban, Marc B; Hyland, Laura L; Yu, Y Bruce
2013-09-01
Enantiomeric biomaterials which are mirror images of each other are characterized by chiral degeneracy--identical structural characteristics and bulk material properties. The addition of another chiral component, D-polysaccharide, has been shown to split such degeneracy and result in two distinct biomaterials. Dynamic oscillatory rheometry and small-angle X-ray scattering demonstrate that the natural biochirality combination of L-peptides and D-polysaccharides assembles faster, has higher elastic moduli (G'), and is structurally more beneficial as opposed to the alternative D-peptide and D-polysaccharide combination. Chemical modifications of the OH-groups in α-D-glucose units in D-polysaccharides weaken such splitting of chiral degeneracy. These findings form a basis to design novel biomaterials and provide additional insight on why proteins and polysaccharides have oppoiste chirality in the biological world. PMID:23879188
CP violation effects on the neutrino degeneracy parameters in the Early Universe
NASA Astrophysics Data System (ADS)
Gava, Jérôme; Volpe, Cristina
2010-09-01
We explore possible CP violating effects, coming from the Dirac phase of the Maki-Nakagawa-Sakata-Pontecorvo matrix, on the neutrino degeneracy parameters, at the epoch of Big-Bang nucleosynthesis. We first demonstrate the conditions under which such effects can arise. In particular it requires that the initial muon and tau neutrino degeneracy parameters ξ differ. Then we solve numerically the kinetic equations for the three flavor neutrino density matrix with the goal of quantifying the impact of the Dirac phase on the electron neutrino degeneracy parameter ξν_e. The calculations include the vacuum term, the coupling to matter, the νν interaction and the collisions. Effects on ξν_e up to almost 1% and on Y of about 0.1% are found, depending on the initial conditions.
Angular-overlap calculation of the Jahn-Teller stabilization energie for f-orbital degeneracies
Warren, K.D.
1980-03-01
The angular-overlap model is applied to the calculation of the linear Jahn-Teller coupling constants for f-orbital degeneracies. The MX/sub 6/, O/sub h/, chromophore is treated as representative of the highest symmetry commonly occurring in the lanthanide and actinide series, and it is shown that, even when spin-orbit effects are taken into account, 5f orbital degeneracies may lead to significant Jahn-Teller stabilization energies. The operation of this effect for F/sup 1/ GAMMA/sub 8/ states is considered. 2 tables.
NASA Astrophysics Data System (ADS)
Bozza, V.; Shvartzvald, Y.; Udalski, A.; Calchi Novati, S.; Bond, I. A.; Han, C.; Hundertmark, M.; Poleski, R.; Pawlak, M.; Szymański, M. K.; Skowron, J.; Mróz, P.; Kozłowski, S.; Wyrzykowski, Ł.; Pietrukowicz, P.; Soszyński, I.; Ulaczyk, K.; OGLE Group; and; Beichman, C.; Bryden, G.; Carey, S.; Fausnaugh, M.; Gaudi, B. S.; Gould, A.; Henderson, C. B.; Pogge, R. W.; Wibking, B.; Yee, J. C.; Zhu, W.; Spitzer Team; Abe, F.; Asakura, Y.; Barry, R. K.; Bennett, D. P.; Bhattacharya, A.; Donachie, M.; Freeman, M.; Fukui, A.; Hirao, Y.; Inayama, K.; Itow, Y.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Nishioka, T.; Ohnishi, K.; Oyokawa, H.; Rattenbury, N.; Saito, To.; Sharan, A.; Sullivan, D. J.; Sumi, T.; Suzuki, D.; Tristram, P. J.; Wakiyama, Y.; Yonehara, A.; MOA Group; Choi, J.-Y.; Park, H.; Jung, Y. K.; Shin, I.-G.; Albrow, M. D.; Park, B.-G.; Kim, S.-L.; Lee, C.-U.; Cha, S.-M.; Kim, D.-J.; Lee, Y.; KMTNet Group; Dominik, M.; Jørgensen, U. G.; Andersen, M. I.; Bramich, D. M.; Burgdorf, M. J.; Ciceri, S.; D'Ago, G.; Evans, D. F.; Figuera Jaimes, R.; Gu, S.-H.; Hinse, T. C.; Kains, N.; Kerins, E.; Korhonen, H.; Kuffmeier, M.; Mancini, L.; Popovas, A.; Rabus, M.; Rahvar, S.; Rasmussen, R. T.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Surdej, J.; Unda-Sanzana, E.; von Essen, C.; Wang, Y.-B.; Wertz, O.; MiNDSTEp; Maoz, D.; Friedmann, M.; Kaspi, S.; Wise Group
2016-03-01
Spitzer microlensing parallax observations of OGLE-2015-BLG-1212 decisively break a degeneracy between planetary and binary solutions that is somewhat ambiguous when only ground-based data are considered. Only eight viable models survive out of an initial set of 32 local minima in the parameter space. These models clearly indicate that the lens is a stellar binary system possibly located within the bulge of our Galaxy, ruling out the planetary alternative. We argue that several types of discrete degeneracies can be broken via such space-based parallax observations.
Buchan, James
2016-06-22
Lies, damned lies and Brexit statistics. It's not been a good month for anyone espousing evidence-based policy and politics after the chair of the Commons health committee switched from Leave to Remain, citing misuse of data by the Leave campaign. PMID:27332589
Tunable Splitting of the Ground-State Degeneracy in Quasi-One-Dimensional Parafermion Systems
NASA Astrophysics Data System (ADS)
Chen, Chun; Burnell, F. J.
2016-03-01
Systems with topologically protected ground-state degeneracies are currently of great interest due to their potential applications in quantum computing. In practice, this degeneracy is never exact, and the magnitude of the ground-state degeneracy splitting imposes constraints on the time scales over which information is topologically protected. In this Letter, we use an instanton approach to evaluate the splitting of topological ground-state degeneracy in quasi-1D systems with parafermion zero modes, in the specific case where parafermions are realized by inducing a superconducting gap in pairs of fractional quantum Hall edges. We show that, like 1D topological superconducting wires, this splitting has an oscillatory dependence on the chemical potential, which arises from an intrinsic Berry phase that produces interference between distinct instanton tunneling events. These Berry phases can be mapped to chiral phases in a (dual) quantum clock model using a Fradkin-Kadanoff transformation. Comparing our low-energy spectrum to that of phenomenological parafermion models allows us to evaluate the real and imaginary parts of the hopping integral between adjacent parafermionic zero modes as functions of the chemical potential.
Tunable Splitting of the Ground-State Degeneracy in Quasi-One-Dimensional Parafermion Systems.
Chen, Chun; Burnell, F J
2016-03-11
Systems with topologically protected ground-state degeneracies are currently of great interest due to their potential applications in quantum computing. In practice, this degeneracy is never exact, and the magnitude of the ground-state degeneracy splitting imposes constraints on the time scales over which information is topologically protected. In this Letter, we use an instanton approach to evaluate the splitting of topological ground-state degeneracy in quasi-1D systems with parafermion zero modes, in the specific case where parafermions are realized by inducing a superconducting gap in pairs of fractional quantum Hall edges. We show that, like 1D topological superconducting wires, this splitting has an oscillatory dependence on the chemical potential, which arises from an intrinsic Berry phase that produces interference between distinct instanton tunneling events. These Berry phases can be mapped to chiral phases in a (dual) quantum clock model using a Fradkin-Kadanoff transformation. Comparing our low-energy spectrum to that of phenomenological parafermion models allows us to evaluate the real and imaginary parts of the hopping integral between adjacent parafermionic zero modes as functions of the chemical potential. PMID:27015499
Symmetry and Degeneracy in Quantum Mechanics. Self-Duality in Finite Spin Systems
ERIC Educational Resources Information Center
Osacar, C.; Pacheco, A. F.
2009-01-01
The symmetry of self-duality (Savit 1980 "Rev. Mod. Phys. 52" 453) of some models of statistical mechanics and quantum field theory is discussed for finite spin blocks of the Ising chain in a transverse magnetic field. The existence of this symmetry in a specific type of these blocks, and not in others, is manifest by the degeneracy of their…
ERIC Educational Resources Information Center
Gould, Arthur
2003-01-01
Analysis of statistics since 1994 on the use of study leave as allowed by a 1974 Swedish law indicates that about 1% of the work force takes leave at any time. Women and manual workers benefit more than men and salaried workers. Leave application causes employees few problems with employers but financial assistance is a concern. (Contains 37…
Tuning Spin- and Valley-Degeneracies in Multicomponent Quantum Well Transport
NASA Astrophysics Data System (ADS)
Prabhu-Gaunkar, Sunanda
The theme of this thesis is manipulation of spin and valley degeneracies in two-dimensional electron systems (2DES) by locally or globally controlling the energy gaps between the two spin states or multiple valley states. Degeneracies in 2DES can be controlled internally or externally with magnetic, strain, and electrostatic fields. With magneto-transport measurements we can probe these spin and valley energy gaps. Spin degeneracies in quantum wells (QW) can be controlled with magnetic field by changing the tilt angle of the field with respect to the sample. Valley degeneracies can be controlled principally by growing QWs of a certain orientation and width. Furthermore, the valley energies can be controlled externally by applying strain or electrostatic gated devices. We first consider transport signatures of controlled spin degeneracies. Magnetic fields can be used to control spin degeneracies and spin gaps by tuning the tilt angle of the field with respect to the sample plane. These spin dependencies can be observed at different tilt angles by conducting measurements of the longitudinal and Hall resistance. In particular, transport measurements in a Si/SiGe spin-split valley degenerate 2DES demonstrates anomalous rise of the transverse Hall resistance at certain quantized plateaus. With systematic tilted field data we map this anomaly to the longitudinal resistance, and also to directional derivatives of the longitudinal resistance. We also develop a theoretical model for estimating the spin-degenerate and spin-split density of states which we fit using the data on longitudinal resistance. We input the exactly calculated spin gaps at every tilt angle in the edge state model of quantum Hall effect, and we are able to provide a microscopic justification to the experimentally observed anomalous features by introducing a constant energy density of disordered states in our model. We next consider transport signatures of controlled valley degeneracies. Valley
NASA Astrophysics Data System (ADS)
Erbe, B.; Schliemann, J.
2010-12-01
We report an unexpected systematic degeneracy between different multiplets in an inversion symmetric system of two coupled Gaudin models with homogeneous couplings, as occurring for example in the context of solid state quantum information processing. We construct the full degenerate subspace (being of macroscopic dimension), which turns out to lie in the kernel of the commutator between the two Gaudin models and the coupling term. Finally we investigate to what extent the degeneracy is related to the inversion symmetry of the system and find that indeed there is a large class of systems showing the same type of degeneracy.
Exceptional point and degeneracy of the neutral Higgs boson system H-A
Felix-Beltran, O.; Gomez-Bock, M.; Hernandez, E.; Mondragon, A.; Mondragon, M.
2009-04-20
We analyze the masses and mixings of the isolated neutral and heavy Higgs fields H and A of the Minimal Supersymmetric Standard Model (MSSM) with CP violation, which have opposite CP parities and nearly degenerate masses. At the degeneracy point, the hypersurfaces that represent the physical masses as functions of the system parameters have a rank one algebraic branch point, and the real and imaginary parts have branch cuts, both starting at the same exceptional point but extending in opposite directions in parameter space. Associated with this singularity, the propagator for the mixed neutral Higgs system H-A has a double pole in the non-physical sheet of the squared energy complex plane s. The continuity of the transition amplitude matrix at the exact degeneracy of the masses is examined.
Afferent hyperexcitability in neuropathic pain and the inconvenient truth about its degeneracy.
Ratté, Stéphanie; Prescott, Steven A
2016-02-01
Neuropathic pain, which arises from damage to the nervous system, is a major unmet clinical challenge. Reversing the neuronal hyperexcitability induced by nerve damage is a logical treatment strategy but has proven frustratingly difficult. Here, we propose a novel explanation for that difficulty. Changes in several different ion channels are individually sufficient to cause hyperexcitability in primary somatosensory neurons. Despite offering multiple drug targets, this scenario is problematic: if multiple sufficient changes are triggered by nerve injury, then no single change is necessary for hyperexcitability. This so-called degeneracy compromises therapeutic interventions because drug effects on any one ion channel can be circumvented by changes occurring in other ion channels. Overcoming degeneracy demands a more integrative approach to drug discovery. PMID:26363576
Taraban, Marc B.; Hyland, Laura L.; Yu, Y. Bruce
2013-09-23
Enantiomeric biomaterials which are mirror images of each other are characterized by chiral degeneracy—identical structural characteristics and bulk material properties. The addition of another chiral component, d-polysaccharide, has been shown to split such degeneracy and result in two distinct biomaterials. Dynamic oscillatory rheometry and small-angle X-ray scattering demonstrate that the natural biochirality combination of l-peptides and d-polysaccharides assembles faster, has higher elastic moduli (G'), and is structurally more beneficial as opposed to the alternative d-peptide and d-polysaccharide combination. Chemical modifications of the OH-groups in α-d-glucose units in d-polysaccharides weaken such splitting of chiral degeneracy. These findings form a basis to design novel biomaterials and provide additional insight on why proteins and polysaccharides have oppoiste chirality in the biological world.
Yu, Li-Wei; Ge, Mo-Lin
2015-01-01
A new realization of doubling degeneracy based on emergent Majorana operator Γ presented by Lee-Wilczek has been made. The Hamiltonian can be obtained through the new type of solution of Yang-Baxter equation, i.e. -matrix. For 2-body interaction, gives the “superconducting” chain that is the same as 1D Kitaev chain model. The 3-body Hamiltonian commuting with Γ is derived by 3-body -matrix, we thus show that the essence of the doubling degeneracy is due to . We also show that the extended Γ′-operator is an invariant of braid group BN for odd N. Moreover, with the extended Γ′-operator, we construct the high dimensional matrix representation of solution to Yang-Baxter equation and find its application in constructing 2N-qubit Greenberger-Horne-Zeilinger state for odd N. PMID:25631987
Approximate degeneracy of heavy-light mesons with the same L
NASA Astrophysics Data System (ADS)
Matsuki, Takayuki; Lü, Qi-Fang; Dong, Yubing; Morii, Toshiyuki
2016-07-01
Careful observation of the experimental spectra of heavy-light mesons tells us that heavy-light mesons with the same angular momentum L are almost degenerate. The estimate is given how much this degeneracy is broken in our relativistic potential model, and it is analytically shown that expectation values of a commutator between the lowest order Hamiltonian and L→2 are of the order of 1 /mQ with a heavy quark mass mQ. It turns out that nonrelativistic approximation of heavy quark system has a rotational symmetry and hence degeneracy among states with the same L. This feature can be tested by measuring higher orbitally and radially excited heavy-light meson spectra for D /Ds / B /Bs in LHCb and forthcoming BelleII.
SPIN-PRECESSION: BREAKING THE BLACK HOLE-NEUTRON STAR DEGENERACY
Chatziioannou, Katerina; Cornish, Neil; Klein, Antoine; Yunes, Nicolás
2015-01-01
Mergers of compact stellar remnants are prime targets for the LIGO/Virgo gravitational wave detectors. The gravitational wave signals from these merger events can be used to study the mass and spin distribution of stellar remnants, and provide information about black hole horizons and the material properties of neutron stars. However, it has been suggested that degeneracies in the way that the star's mass and spin are imprinted in the waveforms may make it impossible to distinguish between black holes and neutron stars. Here we show that the precession of the orbital plane due to spin-orbit coupling breaks the mass-spin degeneracy, and allows us to distinguish between standard neutron stars and alternative possibilities, such as black holes or exotic neutron stars with large masses and spins.
Line Degeneracy and Strong Spin-Orbit Coupling of Light with Bulk Bianisotropic Metamaterials.
Guo, Qinghua; Gao, Wenlong; Chen, Jing; Liu, Yongmin; Zhang, Shuang
2015-08-01
Propagation of light in a medium is dictated by equifrequency surfaces (EFSs), which play a similar role as Fermi surfaces for electrons in crystals. Engineering the equifrequency surface of light through structuring a photonic medium enables superior control over light propagation that goes beyond natural materials. In this Letter, we show that a bulk metamaterial with a suitably designed bianisotropy can exhibit line degeneracy in its EFSs that consist of two ellipsoids of opposite helicity states intersecting with each other. Very interestingly, light propagating along the direction of the line degeneracy experiences strong spin-dependent photon deflection, or optical spin Hall effect, which may lead to applications in optical signal processing and spin-optical manipulations. We provide a realistic metamaterial design to show that the required bianisotropy can be readily obtained. PMID:26296131
Taraban, Marc B.; Hyland, Laura L.; Yu, Y. Bruce
2013-01-01
Enantiomeric biomaterials which are mirror images of each other are characterized by chiral degeneracy—identical structural characteristics and bulk material properties. The addition of another chiral component, D-polysaccharide, has been shown to split such degeneracy and result in two distinct biomaterials. Dynamic oscillatory rheometry and small-angle X-ray scattering demonstrate that the natural biochirality combination of L-peptides and D-polysaccharides assembles faster, has higher elastic moduli (G′), and is structurally more beneficial as opposed to D-peptide and D-polysaccharide combination. Chemical modifications of the OH-groups in α-D-glucose units in D-polysaccharides weaken such splitting of chiral degeneracy. All these findings form a basis to design the approaches to novel biomaterials and provide additional insight on the opposite chirality of proteins and polysaccharides in biological world. PMID:23879188
Effect of valley degeneracy on spin susceptibility of a two-dimensional quantum electron liquid
Kumar, Krishan Singh, Gurvinder; Moudgil, R. K.
2014-04-24
We investigate theoretically the effect of valley degeneracy on the spin susceptibility of a two-dimensional quantum electron liquid by determining the spin-polarization dependence of the ground-state energy within the selfconsistent mean-field approximation of Singwi et al. Specifically, we have studied a two valley system as realized in the Si (100) inversion layer. In qualitative agreement with the recent quantum Monte Carlo study by Marchi et al., we find that the valley degeneracy results in suppression of spin susceptibility over the single valley case. However, the quality of agreement diminishes with increasing value of the coupling parameter r{sub s}. This indicates the limitation of mean-field theory to deal with the exchange-correlation effects in the strong coupling region. But, our results show considerable improvement over the random-phase approximation which ignores these correlations completely.
Dodging the dark matter degeneracy while determining the dynamics of dark energy
NASA Astrophysics Data System (ADS)
Busti, Vinicius C.; Clarkson, Chris
2016-05-01
One of the key issues in cosmology is to establish the nature of dark energy, and to determine whether the equation of state evolves with time. When estimating this from distance measurements there is a degeneracy with the matter density. We show that there exists a simple function of the dark energy equation of state and its first derivative which is independent of this degeneracy at all redshifts, and so is a much more robust determinant of the evolution of dark energy than just its derivative. We show that this function can be well determined at low redshift from supernovae using Gaussian Processes, and that this method is far superior to a variety of parameterisations which are also subject to priors on the matter density. This shows that parametrised models give very biased constraints on the evolution of dark energy.
NASA Astrophysics Data System (ADS)
Guo, Xiaofeng; Nandy, Ashesh
2003-02-01
Some 2-D and 3-D graphical representations of DNA sequences have been given by Gate, Nandy, Leong, Randic, and Guo et al. Based on 2-D graphical representation of DNA sequences, Raychaudhury and Nandy introduced the first-order moments of the x and y coordinates and the radius of the plot of a DNA sequence for indexing scheme and similarity measures of DNA sequences. In this Letter, based on Guo's novel 2-D graphical representation of DNA sequences of low degeneracy, we introduce the improved first-order moments of the x and y coordinates and the radius of DNA sequences, and the distance of two DNA sequences. The new descriptors of DNA sequences give a good numerical characterization of DNA sequences, which have lower degeneracy.
Macroscopic degeneracy and order in the 3D plaquette Ising model
NASA Astrophysics Data System (ADS)
Johnston, Desmond A.; Mueller, Marco; Janke, Wolfhard
2015-07-01
The purely plaquette 3D Ising Hamiltonian with the spins living at the vertices of a cubic lattice displays several interesting features. The symmetries of the model lead to a macroscopic degeneracy of the low-temperature phase and prevent the definition of a standard magnetic order parameter. Consideration of the strongly anisotropic limit of the model suggests that a layered, “fuki-nuke” order still exists and we confirm this with multi-canonical simulations. The macroscopic degeneracy of the low-temperature phase also changes the finite-size scaling corrections at the first-order transition in the model and we see this must be taken into account when analyzing our measurements.
Lifting of the Landau level degeneracy in graphene devices in a tilted magnetic field
NASA Astrophysics Data System (ADS)
Chiappini, F.; Wiedmann, S.; Novoselov, K.; Mishchenko, A.; Geim, A. K.; Maan, J. C.; Zeitler, U.
2015-11-01
We report on transport and capacitance measurements of graphene devices in magnetic fields up to 30 T. In both techniques, we observe the full splitting of Landau levels and we employ tilted field experiments to address the origin of the observed broken symmetry states. In the lowest energy level, the spin degeneracy is removed at filling factors ν =±1 and we observe an enhanced energy gap. In the higher levels, the valley degeneracy is removed at odd filling factors while spin polarized states are formed at even ν . Although the observation of odd filling factors in the higher levels points towards the spontaneous origin of the splitting, we find that the main contribution to the gap at ν =-4 ,-8 , and -12 is due to the Zeeman energy.
Interaction of characteristic waves in a plasma in the case of triple degeneracy
NASA Astrophysics Data System (ADS)
Viatkin, V. M.; Novikov, V. V.
1989-06-01
The paper investigates waves transformation in an inhomogeneous magnetoplasma in regions where the three roots of the Booker quartic are equal. It is shown that an extraordinary wave incident on the interaction region splits into an ordinary wave and an extraordinary wave traveling in the same direction and a reflected ordinary wave. An ordinary wave incident on the triple-degeneracy point is completely transformed into an extraordinary wave.
Urrestilla, Jon; Mukherjee, Pia; Liddle, Andrew R.; Hindmarsh, Mark; Kunz, Martin; Bevis, Neil
2008-06-15
While observations indicate that the predominant source of cosmic inhomogeneities are adiabatic perturbations, there are a variety of candidates to provide auxiliary trace effects, including inflation-generated primordial tensors and cosmic defects which both produce B-mode cosmic microwave background polarization. We investigate whether future experiments may suffer confusion as to the true origin of such effects, focusing on the ability of Planck to distinguish tensors from cosmic strings, and show that there is no significant degeneracy.
Red queen dynamics and the evolution of translational redundancy and degeneracy
NASA Astrophysics Data System (ADS)
Krakauer, David C.; Jansen, Vincent A. A.; Nowak, Martin
We explore adaptive theories for the diversity of protein translation based on the genetic code viewed as a primitive immune system. Immunity is acquired through a genetic mechanism of non-recognition of parasite genomes. Modifying the set of codons bound by tRNA anticodon molecules or changing the specificity of binding, reduces the replication rate of translational parasites such as viruses. Changing the binding specifity can be thought of in terms of varying degrees of redundancy an d degeneracy. Redundancy in the genetic code is commonly attributed to using a four base triplet mechanism to encode the 20 amino acids. This has been referred to as synonym redundancy. There are however at least a further two forms of redundancy associated with the code and one source of degeneracy. A first form of redundancy arises from decoding all 61 possible sense codons using fewer than 61 anticodons. Such a strategy involves reduced binding specificity. A second source of redundancy is present in the multiplicity of copies of each unique tRNA (tRNA copy redundancy). Degeneracy arises when different anticodons become associated with a single amino acid to increase specificity. Variation in these strategies across taxa ensures that the translational machinery is diverse whereas the code remains approximately constant. We construct a red queen theory for translational diversity: a theory in which host translational strategies - as defined by the degree of redundancy or degeneracy of anticodons - are const antly shifting through time to evade parasitism but where neither parasite nor host gains a systematic advantage.
Halogenated benzene radical cations and ground state degeneracy splitting by asymmetric substitution
Bondybey, V.E.; Vaughn, C.R.; Miller, T.A.; English, J.H.; Shiley, R.H.
1981-01-01
The absorption and laser induced fluorescence of several halogenated benzene radical cations were studied in solid Ne matrices. The spectra of 1,2,4-trifluorobenzene, l,3-dichloro-5-fluorobenzene, and l-chloro-3,5- difluorobenzene radical cations are observed and analyzed. Studies of fluorescence polarization and a photoselection technique were used to examine the splitting of the degeneracy of the benzene cation ground state by asymmetric subsitution. ?? 1981 American Institute of Physics.
Single-centered black hole microstate degeneracies from instantons in supergravity
NASA Astrophysics Data System (ADS)
Murthy, Sameer; Reys, Valentin
2016-04-01
We obtain holographic constraints on the microscopic degeneracies of black holes by computing the exact macroscopic quantum entropy using localization, including the effects of string worldsheet instantons in the supergravity effective action. For 1/4 -BPS black holes in type II string theory on K3 × T 2, the constraints can be explicitly checked against expressions for the microscopic BPS counting functions that are known in terms of certain mock modular forms. We find that the effect of including the infinite sum over instantons in the holomorphic prepotential of the supergravity leads to a sum over Bessel functions with successively sub-leading arguments as in the Rademacher expansion of Jacobi forms — but begins to disagree with such a structure near an order where the mock modular nature becomes relevant. This leads to a systematic method to recover the polar terms of the microscopic degeneracies from the degeneracy of instantons (the Gromov-Witten invariants). We check explicitly that our formula agrees with the known microscopic answer for the first seven values of the magnetic charge invariant.
Problematising Early School Leaving
ERIC Educational Resources Information Center
Ross, Alistair; Leathwood, Carole
2013-01-01
Early school leaving has been identified as a key policy priority across Europe. In this article, we critically discuss the underpinning assumptions and rationale for this policy focus, challenging the association that is made between early school leaving, economic growth and employment. We suggest that ESL is important, not because it is…
Delineation of a recognizable phenotype for the recurrent LCR22-C to D/E atypical 22q11.2 deletion.
Bengoa-Alonso, Amaya; Artigas-López, Mercè; Moreno-Igoa, María; Cattalli, Claudio; Hernández-Charro, Blanca; Ramos-Arroyo, Maria Antonia
2016-06-01
The 22q11.2 deletion syndrome is typically caused by haploinsufficiency of a 3 Mb region that extends from LCR22-A until LCR22-D, while the recurrent recombination between any of the LCR22-D to H causes the 22q11.2 distal deletion syndrome. Here, we describe three patients with a de novo atypical ∼1.4 Mb 22q11.2 deletion that involves LCR22-C to a region beyond D (LCR22-C to D/E), encompassing the distal portion of the typical deleted region and the proximal portion of the distal deletion. We also review six previous published patients with the same rearrangement and compare their features with those found in patients with overlapping deletions. Patients with LCR22-C to D/E deletion present a recognizable phenotype characterized by facial dysmorphic features, high frequency of cardiac defects, including conotruncal defects, prematurity, growth restriction, microcephaly, and mild developmental delay. Genotype-phenotype analysis of the patients indicates that CRKL and MAPK1 genes play an important role as causative factors for the main clinical features of the syndrome. In particular, CRKL gene seems to be involved in the occurrence of conotruncal cardiac anomalies, mainly tetralogy of Fallot. © 2016 Wiley Periodicals, Inc. PMID:26991864
Yun, Kyungwon; Lee, Hyunjae; Bang, Hyunwoo; Jeon, Noo Li
2016-02-21
This study proposes a novel way to achieve high-throughput image acquisition based on a computer-recognizable micro-pattern implemented on a microfluidic device. We integrated the QR code, a two-dimensional barcode system, onto the microfluidic device to simplify imaging of multiple ROIs (regions of interest). A standard QR code pattern was modified to arrays of cylindrical structures of polydimethylsiloxane (PDMS). Utilizing the recognition of the micro-pattern, the proposed system enables: (1) device identification, which allows referencing additional information of the device, such as device imaging sequences or the ROIs and (2) composing a coordinate system for an arbitrarily located microfluidic device with respect to the stage. Based on these functionalities, the proposed method performs one-step high-throughput imaging for data acquisition in microfluidic devices without further manual exploration and locating of the desired ROIs. In our experience, the proposed method significantly reduced the time for the preparation of an acquisition. We expect that the method will innovatively improve the prototype device data acquisition and analysis. PMID:26728124
NASA Astrophysics Data System (ADS)
Jontof-Hutter, Daniel; Van Laerhoven, Christa L.; Ford, Eric B.
2016-05-01
Hundreds of multi-transiting systems discovered by the Kepler mission show Transit Timing Variations (TTV). In cases where the TTVs are uniquely attributable to transiting planets, the TTVs enable precise measurements of planetary masses and orbital parameters. Of particular interest are the constraints on eccentricity vectors that can be inferred in systems of low-mass exoplanets.The TTVs in these systems are dominated by a signal caused by near-resonant mean motions. This causes the well-known near-degeneracy between planetary masses and orbital eccentricities. In addition, it causes a degeneracy between the eccentricities of interacting planet pairs.For many systems, the magnitude of individual eccentricities are weakly constrained, yet the data typically provide a tight constraint on the posterior joint distribution for the eccentricity vector components. This permits tight constraints on the relative eccentricity and degree of alignment of interacting planets.For a sample of two and three-planet systems with TTVs, we highlight the effects of these correlations. While the most eccentric orbital solutions for these systems show apsidal alignment, this is often due to the degeneracy that causes correlated constraints on the eccentricity vector components. We compare the likelihood of apsidal alignment for two choices of eccentricity prior: a wide prior using a Rayleigh distribution of scale length 0.1 and a narrower prior with scale length 0.02. In all cases the narrower prior decreased the fraction of samples that exhibited apsidal alignment. However, apsidal alignment persisted in the majority of cases with a narrower eccentricity prior. For a sample of our TTV solutions, we ran simulations of these systems over secular timescales, and decomposed their eccentricity eigenmodes over time, confirming that in most cases, the eccentricities were dominated by parallel eigenmodes which favor apsidal alignment.
NASA Astrophysics Data System (ADS)
Milewski, J.; Lulek, B.; Lulek, T.; Łabuz, M.; Stagraczyński, R.
2014-02-01
The exact Bethe eigenfunctions for the heptagonal ring within the isotropic XXX model exhibit a doubly degenerated energy level in the three-deviation sector at the centre of the Brillouin zone. We demonstrate an explicit construction of these eigenfunctions by use of algebraic Bethe Ansatz, and point out a relation of degeneracy to parity conservation, applied to the configuration of strings for these eigenfunctions. Namely, the internal structure of the eigenfunctions (the 2-string and the 1-string, with opposite quasimomenta) admits generation of two mutually orthogonal eigenfunctions due to the fact that the strings which differ by their length are distinguishable objects.
Vakoc, B J; Yun, S H; Tearney, G J; Bouma, B E
2006-02-01
A novel optical frequency-domain imaging system is demonstrated that employs a passive optical demodulation circuit and a chirped digital acquisition clock derived from a voltage-controlled oscillator. The demodulation circuit allows the separation of signals from positive and negative depths to better than 50 dB, thereby eliminating depth degeneracy and doubling the imaging depth range. Our system design is compatible with dual-balanced and polarization-diverse detection, important techniques in the practical biomedical application of optical frequency-domain imaging. PMID:16480209
Cluster-Void Degeneracy Breaking: Dark Energy, Planck, and the Largest Cluster and Void
NASA Astrophysics Data System (ADS)
Sahlén, Martin; Zubeldía, Íñigo; Silk, Joseph
2016-03-01
Combining galaxy cluster and void abundances breaks the degeneracy between mean matter density {{{Ω }}}{{m}} and power-spectrum normalization {σ }8. For the first time for voids, we constrain {{{Ω }}}{{m}}=0.21+/- 0.10 and {σ }8=0.95+/- 0.21 for a flat Λ CDM universe, using extreme-value statistics on the claimed largest cluster and void. The Planck-consistent results detect dark energy with two objects, independently of other dark energy probes. Cluster-void studies are also complementary in scale, density, and nonlinearity, and are of particular interest for testing modified-gravity models.
A novel 2-D graphical representation of DNA sequences of low degeneracy
NASA Astrophysics Data System (ADS)
Guo, Xiaofeng; Randic, Milan; Basak, Subhash C.
2001-12-01
Some 2-D and 3-D graphical representations of DNA sequences have been given by Nandy, Leong and Mogenthaler, and Randic et al., which give visual characterizations of DNA sequences. In this Letter, we introduce a novel graphical representation of DNA sequences by taking four special vectors in 2-D space to represent the four nucleic acid bases in DNA sequences, so that a DNA sequence is denoted on a plane by a successive vector sequence, which is also a directed walk on the plane. It is showed that the novel graphical representation of DNA sequences has lower degeneracy and less overlapping.
ERIC Educational Resources Information Center
Kernan, Christine
2002-01-01
Describes an art project that integrated science and art education. Explains that students create ceramic bowls by using real leaves. Discusses the process of creating the ceramic bowls, including how to glaze the bowls. Includes a list of materials. (CMK)
Proton stopping using a full conserving dielectric function in plasmas at any degeneracy
Barriga-Carrasco, Manuel D.
2010-10-15
In this work, we present a dielectric function including the three conservation laws (density, momentum and energy) when we take into account electron-electron collisions in a plasma at any degeneracy. This full conserving dielectric function (FCDF) reproduces the random phase approximation (RPA) and Mermin ones, which confirms this outcome. The FCDF is applied to the determination of the proton stopping power. Differences among diverse dielectric functions in the proton stopping calculation are minimal if the plasma electron collision frequency is not high enough. These discrepancies can rise up to 2% between RPA values and the FCDF ones, and to 8% between the Mermin ones and FCDF ones. The similarity between RPA and FCDF results is not surprising, as all conservation laws are also considered in RPA dielectric function. Even for plasmas with low collision frequencies, those discrepancies follow the same behavior as for plasmas with higher frequencies. Then, discrepancies do not depend on the plasma degeneracy but essentially do on the value of the plasma collision frequency.
Resolving the degeneracy in single Higgs production with Higgs pair production
NASA Astrophysics Data System (ADS)
Cao, Qing-Hong; Yan, Bin; Zhang, Dong-Ming; Zhang, Hao
2016-01-01
The Higgs boson production can be affected by several anomalous couplings, e.g. ct and cg anomalous couplings. Precise measurement of gg → h production yields two degenerate parameter spaces of ct and cg; one parameter space exhibits the SM limit while the other does not. Such a degeneracy could be resolved by Higgs boson pair production. In this work we adapt the strategy suggested by the ATLAS collaboration to explore the potential of distinguishing the degeneracy at the 14 TeV LHC. If the ct anomalous coupling is induced only by the operator H† HQbarL H ˜ tR, then the non-SM-like band could be excluded with an integrated luminosity of ˜ 210 fb-1. Making use of the fact that the Higgs boson pair is mainly produced through an s-wave scattering, we propose an analytical function to describe the fraction of signal events surviving a series of experimental cuts for a given invariant mass of Higgs boson pair. The function is model independent and can be applied to estimate the discovery potential of various NP models.
Quantum degeneracy effect on the work output from a Stirling cycle
NASA Astrophysics Data System (ADS)
Saygin, Hasan; Şişman, Altuǧ
2001-09-01
The effect of quantum degeneracy on the work output from a Stirling cycle working at quantum degeneracy conditions (QDCs) is analyzed. Expressions for net work outputs of Stirling power cycles working with monatomic ideal Bose and Fermi gases are derived by using the quantum ideal gas equation of state. Ratios of net work outputs of Stirling cycles working with Bose and Fermi gases to the net work output of a classical Stirling cycle (RWB and RWF, respectively) are obtained. Variations of RWB and RWF with TH are examined for a given temperature ratio (τ=TL/TH) and a specific volume ratio (rν=νH/νL). At QDC, it is seen that RWB has a maximum value, which is greater than unity. On the other hand, there is no maximum or minimum point for RWF and RWF⩽1 for any values of TH. Consequently, the use of Bose gas as a working fluid in a Stirling cycle provides an advantage since it causes the net work output per cycle to increase by consuming more heat energy. This fact is seen to be in the opposite direction for a Stirling cycle working with Fermi gas.
Gutzwiller approach to the Anderson lattice model with no orbital degeneracy
NASA Astrophysics Data System (ADS)
Vulović, Vladimir Z.; Abrahams, Elihu
1987-08-01
A new technique is used to obtain the Gutzwiller ground-state energy functional for the Anderson lattice model with no orbital degeneracy (ALM). For the Hubbard model, known expressions are derived with ease and simplicity. For the ALM, we derive the ground-state energy functional of Varma, Weber, and Randall. As a check on our Gutzwiller functional, we find an independent analytical upper bound for the ground-state energy of ALM with a dispersionless f band. For the case of a dispersionless f band and momentum-independent hybridization, in the Kondo regime, we derive analytical expressions for the ground-state energy, charge, and magnetic susceptibilities. For the special case of infinite Coulomb repulsion, we recover results of Rice and Ueda and of Fazekas and Brandow, notably the negative value of the magnetic susceptibility. The negative magnetic susceptibility persists in the entire Kondo region, i.e., finite-U effects do not stabilize the nonmagnetic Kondo state. This suggests that nonzero orbital degeneracy in the Anderson lattice model must be retained to describe heavy-fermion materials with a normal Fermi liquid ground state.
Unhappy vertices in artificial spin ice: new degeneracies from vertex frustration
NASA Astrophysics Data System (ADS)
Morrison, Muir J.; Nelson, Tammie R.; Nisoli, Cristiano
2013-04-01
In 1935, Pauling estimated the residual entropy of water ice with remarkable accuracy by considering the degeneracy of the ice rule solely at the vertex level. Indeed, his estimate works well for both the three-dimensional pyrochlore lattice and the two-dimensional six-vertex model, solved by Lieb in 1967. A similar estimate can be done for the honeycomb artificial spin. Indeed, its pseudo-ice rule, like the ice rule in Pauling and Lieb's systems, simply extends to the global ground state a degeneracy which is already present in the vertices. Unfortunately, the anisotropy of the magnetic interaction limits the design of inherently degenerate vertices in artificial spin ice, and the honeycomb is the only degenerate array produced so far. In this paper we show how to engineer artificial spin ice in a virtually infinite variety of degenerate geometries built out of non-degenerate vertices. In this new class of vertex models, the residual entropy follows not from a freedom of choice at the vertex level, but from the nontrivial relative arrangement of the vertices themselves. In such arrays not all of the vertices can be chosen in their lowest energy configuration. They are therefore vertex-frustrated and contain unhappy vertices. This can lead to residual entropy and to a variety of exotic states, such as sliding phases, smectic phases and emerging chirality. These new geometries will finally allow for the fabrication of many novel, extensively degenerate versions of artificial spin ice.
On the Degeneracies of the Mass-Squared Differences for Three-Neutrino Oscillations
NASA Astrophysics Data System (ADS)
Latimer, D. C.; Ernst, D. J.
Using an algebraic formulation, we explore two well-known degeneracies involving the mass-squared differences for three-neutrino oscillations assuming CP symmetry is conserved. For vacuum oscillation, we derive the expression for the mixing angles that permit invariance under the interchange of two mass-squared differences. This symmetry is most easily expressed in terms of an ascending mass order. This can be used to reduce the parameter space by one half in the absence of the MSW effect. For oscillations in matter, we derive within our formalism the known approximate degeneracy between the standard and inverted mass hierarchies in the limit of vanishing θ13. This is done with a mass ordering that permits the map Δ31↦-Δ31. Our techniques allow us to translate mixing angles in this mass order convention into their values for the ascending order convention. Using this dictionary, we demonstrate that the vacuum symmetry and the approximate symmetry invoked for oscillations in matter are distinctly different.
Ogata, Tsutomu; Kagami, Masayo
2016-02-01
Human chromosome 14q32.2 carries paternally expressed genes including DLK1 and RTL1, and maternally expressed genes including MEG3 and RTL1as, along with the germline-derived DLK1-MEG3 intergenic differentially methylated region (IG-DMR) and the postfertilization-derived MEG3-DMR. Consistent with this, paternal uniparental disomy 14 (upd(14)pat), and epimutations (hypermethylations) and microdeletions affecting the IG-DMR and/or the MEG3-DMR of maternal origin, result in a unique phenotype associated with characteristic face, a small bell-shaped thorax with coat-hanger appearance of the ribs, abdominal wall defects, placentomegaly and polyhydramnios. Recently, the name 'Kagami-Ogata syndrome' (KOS) has been approved for this clinically recognizable disorder. Here, we review the current knowledge about KOS. Important findings include the following: (1) the facial 'gestalt' and the increased coat-hanger angle constitute pathognomonic features from infancy through childhood/puberty; (2) the unmethylated IG-DMR and MEG3-DMR of maternal origin function as the imprinting control centers in the placenta and body respectively, with a hierarchical interaction regulated by the IG-DMR for the methylation pattern of the MEG3-DMR in the body; (3) RTL1 expression level becomes ~2.5 times increased in the absence of functional RTL1as-encoded microRNAs that act as a trans-acting repressor for RTL1; (4) excessive RTL1 expression and absent MEG expression constitute the primary underlying factor for the phenotypic development; and (5) upd(14)pat accounts for approximately two-thirds of KOS patients, and epimutations and microdeletions are identified with a similar frequency. Furthermore, we refer to diagnostic and therapeutic implications. PMID:26377239
Ogata, Tsutomu; Kagami, Masayo
2016-01-01
Human chromosome 14q32.2 carries paternally expressed genes including DLK1 and RTL1, and maternally expressed genes including MEG3 and RTL1as, along with the germline-derived DLK1-MEG3 intergenic differentially methylated region (IG-DMR) and the postfertilization-derived MEG3-DMR. Consistent with this, paternal uniparental disomy 14 (upd(14)pat), and epimutations (hypermethylations) and microdeletions affecting the IG-DMR and/or the MEG3-DMR of maternal origin, result in a unique phenotype associated with characteristic face, a small bell-shaped thorax with coat-hanger appearance of the ribs, abdominal wall defects, placentomegaly and polyhydramnios. Recently, the name ‘Kagami–Ogata syndrome' (KOS) has been approved for this clinically recognizable disorder. Here, we review the current knowledge about KOS. Important findings include the following: (1) the facial ‘gestalt' and the increased coat-hanger angle constitute pathognomonic features from infancy through childhood/puberty; (2) the unmethylated IG-DMR and MEG3-DMR of maternal origin function as the imprinting control centers in the placenta and body respectively, with a hierarchical interaction regulated by the IG-DMR for the methylation pattern of the MEG3-DMR in the body; (3) RTL1 expression level becomes ~2.5 times increased in the absence of functional RTL1as-encoded microRNAs that act as a trans-acting repressor for RTL1; (4) excessive RTL1 expression and absent MEG expression constitute the primary underlying factor for the phenotypic development; and (5) upd(14)pat accounts for approximately two-thirds of KOS patients, and epimutations and microdeletions are identified with a similar frequency. Furthermore, we refer to diagnostic and therapeutic implications. PMID:26377239
Conformal symmetry breaking and degeneracy of high-lying unflavored mesons
NASA Astrophysics Data System (ADS)
Kirchbach, Mariana; Pallares-Rivera, Adrian; Compean, Cliffor; Raya, Alfredo
2012-08-01
We show that though conformal symmetry can be broken by the dilaton, such can happen without breaking the conformal degeneracy patterns in the spectra. Our argumentation goes as follows: We departure from the gauge-gravity duality which predicts on the boundaries of the AdS5 geometry a conformal theory, associated with QCD at high temperatures, and consider S1 × S3 slicing. The inverse radius, R, of S3 relates to the temperature of the deconfinement phase transition and has to satisfy, hslashc/R gg ΛQCD. On S3, whose isometry group is SO(4), we then focus on the eigenvalue problem of the conformal Laplacian there, given by , with standing for the Casimir invariant of the so(4) algebra. This eigenvalue problem describes the spectrum of a scalar particle, to be associated with a qbar q system. Such a spectrum is characterized by a (K + l)2-fold degeneracy of its levels, with K in [0, ∞). We then break the conformal S3 metric, ds2 = dχ2 + sin2 χ(dθ2 + sin2θdvarphi2) -in polar chi,θ, and azimuthal varphi coordinates- according to, ds~2 = e-bχ((1 + b2/4)dχ2 + sin2 chi(dθ2 + sin2θdvarphi2)), and attribute the symmetry breaking scale bhslash2c2/R2 to the dilaton. Next we show that the above metric deformation is equivalent to a breaking of the conformal curvature of S3 by a term proportional to b cot χ, and that the perturbed conformal Laplacian is equivalent to , with cκ a representation constant, and being again an so(4) Casimir invariant, but this time in a representation unitarily nonequivalent to the 4D rotational one. As long as the spectra before and after the symmetry breaking happen to be determined each by eigenvalues of a Casimir invariant of an so(4), no matter whether or not in a representation that generates the orthogonal group SO(4) as a subgroup of the conformal group SO(2,4), the degeneracy patterns remain unaltered though the conformal symmetry breaks at the level of the representation of the algebra. We fit the S3 radius and the hslash2c
Hyperspherical theory of the quantum Hall effect: The role of exceptional degeneracy
NASA Astrophysics Data System (ADS)
Daily, K. M.; Wooten, R. E.; Greene, Chris H.
2015-09-01
By separating the Schrödinger equation for N noninteracting spin-polarized fermions in two-dimensional hyperspherical coordinates, we demonstrate that fractional quantum Hall (FQH) states emerge naturally from degeneracy patterns of the antisymmetric free-particle eigenfunctions. In the presence of Coulomb interactions, the FQH states split off from a degenerate manifold and become observable as distinct quantized energy eigenstates with an energy gap. This alternative classification scheme is based on an approximate separability of the interacting N -fermion Schrödinger equation in the hyperradial coordinate, which sheds light on the emergence of Laughlin states as well as other FQH states. An approximate good collective quantum number, the grand angular momentum K from K -harmonic few-body theory, is shown to correlate with known FQH states at many filling factors observed experimentally.
Degeneracy of Majorana bound states and fractional Josephson effect in a dirty SNS junction.
Ikegaya, S; Asano, Y
2016-09-21
We theoretically study the stability of more than one Majorana fermion appearing in a p-wave superconductor/dirty normal metal/p-wave superconductor junction in two-dimensions by using the chiral symmetry of a Hamiltonian. At the phase difference across the junction φ being π, we will show that all of the Majorana bound states in the normal metal belong to the same chirality. Due to this pure chiral feature, the Majorana bound states retain their high degree of degeneracy at zero energy even in the presence of a random potential. As a consequence, the resonant transmission of a Cooper pair via the degenerate Majorana bound states carries the Josephson current at [Formula: see text], which explains the fractional current-phase relationship discussed in a number of previous papers. PMID:27420174
Degeneracies and exotic phases in an isotropic frustrated spin-1/2 chain
NASA Astrophysics Data System (ADS)
Parvej, Aslam; Kumar, Manoranjan
2016-03-01
In the presence of an axial magnetic field, a frustrated isotropic J1 - J2 model system shows many exotic phases, such as vector chiral and multipolar phases. In this paper, the phase boundaries of these exotic phases are calculated based on the order parameters, energy level crossings and magnetization jumps in the system. The order parameter of the vector chiral phase is calculated using the broken symmetry states at a finite magnetic field. The exact diagonalization and the density matrix renormalization group results are used to show that the vector chiral phase exists only in a narrow range of J2/J1 parameter space. In the quadrupolar phase, the magnetization jumps can be associated with the binding energy of two magnons localized at two different legs of the zigzag chain. The energy level crossings and degeneracies in the presence of the axial magnetic field are studied in detail using the exact diagonalization method.
Influence of quantum degeneracy on the performance of a gas Stirling engine cycle
NASA Astrophysics Data System (ADS)
He, Ji-Zhou; Mao, Zhi-Yuan; Wang, Jian-Hui
2006-09-01
Based on the state equation of an ideal quantum gas, the regenerative loss of a Stirling engine cycle working with an ideal quantum gas is calculated. Thermal efficiency of the cycle is derived. Furthermore, under the condition of quantum degeneracy, several special thermal efficiencies are discussed. Ratios of thermal efficiencies versus the temperature ratio and volume ratio of the cycle are made. It is found that the thermal efficiency of the cycle not only depends on high and low temperatures but also on maximum and minimum volumes. In a classical gas state the thermal efficiency of the cycle is equal to that of the Carnot cycle. In an ideal quantum gas state the thermal efficiency of the cycle is smaller than that of the Carnot cycle. This will be significant for deeper understanding of the gas Stirling engine cycle.
Protein evolution. Pervasive degeneracy and epistasis in a protein-protein interface.
Podgornaia, Anna I; Laub, Michael T
2015-02-01
Mapping protein sequence space is a difficult problem that necessitates the analysis of 20(N) combinations for sequences of length N. We systematically mapped the sequence space of four key residues in the Escherichia coli protein kinase PhoQ that drive recognition of its substrate PhoP. We generated a library containing all 160,000 variants of PhoQ at these positions and used a two-step selection coupled to next-generation sequencing to identify 1659 functional variants. Our results reveal extensive degeneracy in the PhoQ-PhoP interface and epistasis, with the effect of individual substitutions often highly dependent on context. Together, epistasis and the genetic code create a pattern of connectivity of functional variants in sequence space that likely constrains PhoQ evolution. Consequently, the diversity of PhoQ orthologs is substantially lower than that of functional PhoQ variants. PMID:25657251
Giant and tunable valley degeneracy splitting in MoTe2
NASA Astrophysics Data System (ADS)
Li, Xiao; Qi, Jingshan; Niu, Qian; Feng, Ji
Valleys in monolayer transition-metal dichalcogenides seamlessly connect two basic carriers of quantum information, namely, the electron spin and photon helicity. Lifting the valley degeneracy is an attractive route to achieve further optoelectronic manipulations. However, the magnetic field only creates a very small valley splitting. We propose a strategy to create giant valley splitting by the proximity-induced Zeeman effect. Our first principles calculations of monolayer MoTe2 on a EuO substrate show that valley splitting over 300 meV can be generated. Interband transition energies become valley dependent, leading to selective spin-photon coupling by optical frequency tuning. The valley splitting is also continuously tunable by rotating the substrate magnetization. The giant and tunable valley splitting adds a different dimension to the exploration of unique optoelectronic devices based on magneto-optical coupling and magnetoelectric coupling.
Partially ferromagnetic electromagnet for trapping and cooling neutral atoms to quantum degeneracy
Fauquembergue, M.; Riou, J-F.; Guerin, W.; Rangwala, S.; Moron, F.; Villing, A.; Le Coq, Y.; Bouyer, P.; Aspect, A.; Lecrivain, M.
2005-10-15
We have developed a compact partially ferromagnetic electromagnet to produce an Ioffe-Pritchard trap for neutral atoms. Our structure permits strong magnetic confinement with low power consumption. Compared to the previous iron-core electromagnet [B. Desruelle, V. Boyer, P. Bouyer, G. Birkl, M. Lecrivain, F. Alves, C. Westbrook, and A. Aspect, Eur. Phys. J. D 1, 255 (1998)], it allows for easy compensation of remnant fields and very high stability, along with cost-effective realization and compactness. We describe and characterize our apparatus and demonstrate trapping and cooling of {sup 87}Rb atoms to quantum degeneracy. Pure Bose-Einstein condensates containing 10{sup 6} atoms are routinely realized on a half-minute cycle. In addition we test the stability of the magnetic trap by producing atom lasers.
Degeneracy of Majorana bound states and fractional Josephson effect in a dirty SNS junction
NASA Astrophysics Data System (ADS)
Ikegaya, S.; Asano, Y.
2016-09-01
We theoretically study the stability of more than one Majorana fermion appearing in a p-wave superconductor/dirty normal metal/p-wave superconductor junction in two-dimensions by using the chiral symmetry of a Hamiltonian. At the phase difference across the junction φ being π, we will show that all of the Majorana bound states in the normal metal belong to the same chirality. Due to this pure chiral feature, the Majorana bound states retain their high degree of degeneracy at zero energy even in the presence of a random potential. As a consequence, the resonant transmission of a Cooper pair via the degenerate Majorana bound states carries the Josephson current at \\varphi =π -{{0}+} , which explains the fractional current-phase relationship discussed in a number of previous papers.
Coexistence of orbital degeneracy lifting and superconductivity in iron-based superconductors
NASA Astrophysics Data System (ADS)
Miao, Hu; Richard, Pierre; Wu, Shangfei; Ma, Jun; Qian, Tian; Xing, Lingyi; Wang, Xiancheng; Jin, Changqing; Ding, Hong; Chou, Chungpin; Wang, Limin; Ku, Wei; Wang, Ziqiang
2014-03-01
In iron-based superconductors, local orbital fluctuations have been proposed to be directly responsible for the structural phase transition and closely related to the observed giant magnetic anisotropy and electronic nematicity. However, whether superconductivity can emerge from, or even coexist with orbital fluctuations, remains unclear. Here we report the angle-resolved photoemission spectroscopy observation of the lifting of symmetry-protected band degeneracy, and consequently the breakdown of local tetragonal symmetry in the SC state of Li(Fe1-xCox)As. Supported by theoretical simulations, we analyse the doping and temperature dependences of this band-splitting and demonstrate an intimate connection between ferro-orbital correlations and superconductivity. This work was supported by grants from CAS, MOST and NSFC. Theoretical study is supported by US DOE. This work is based in part on research conducted at the Synchrotron Radiation Center, which is primarily funded by the University of Wisconsin-Madison.
2012-01-01
recognizable although variable phenotype consisting of a specific form of pontocerebellar hypoplasia. In addition, we report the second male patient to present with a severe MICPCH phenotype and a de novo CASK mutation and describe for the first time a mildly affected male patient harboring a mosaic mutation. In our reference centre, CASK related PCH is the second most frequent cause of PCH. The identification of a de novo mutation in these patients enables accurate and reassuring genetic counselling. PMID:22452838
Leaves: Nature's Solar Collectors
ERIC Educational Resources Information Center
Isabelle, Aaron D.; de Groot, Cornelis
2009-01-01
One of the most captivating things about plants is the way they capture the Sun's energy, but this can be a difficult topic to cover with elementary students. Therefore, to help students to make a concrete connection to this abstract concept, this series of solar-energy lessons focuses on leaves and how they act as "solar collectors." As students…
Bemoans, Belittles, and Leaves
ERIC Educational Resources Information Center
Lynch-Biniek, Amy
2005-01-01
In this article, I examine Lynn Truss's book of punctuation rules and faux pas, "Eats, Shoots & Leaves," contemplating the complex relationships among class, academics, and language snobbery. I don't refute Truss's lessons on punctuation. Instead, I use her text as a jumping-off point for discussion of the social issues embedded in her guide and…
Feng, Joyce Yen; Han, Wen-Jui
2011-01-01
Using the first nationally representative birth cohort study in Taiwan, this paper examines the role that maternity leave policy in Taiwan plays in the timing of mothers returning to work after giving birth, as well as the extent to which this timing is linked to the amount of time mothers spend with their children and their use of breast milk versus formula. We found that the time when mothers returned to work coincided with the duration of guaranteed leave. In particular, mothers with a labor pension plan resumed work significantly earlier than mothers with no pension plan, and mothers with no pension plan returned to work significantly later than those with pension plans. The short leave of absence guaranteed under existing policies translated into mothers spending less time with their children and being more likely to exclusively use formula by 6 months after birth. In contrast, mothers who resumed work later than 6 months after birth were more likely to have not worked before birth or to have quit their jobs during pregnancy. Implications and recommendations for parental leave policy in Taiwan are discussed. PMID:21603074
ERIC Educational Resources Information Center
Feng, Joyce Yen; Han, Wen-Jui
2010-01-01
Using the first nationally representative birth cohort study in Taiwan, this paper examines the role that maternity leave policy in Taiwan plays in the timing of mothers returning to work after giving birth, as well as the extent to which this timing is linked to the amount of time mothers spend with their children and their use of breast milk…
Observation of non-Hermitian degeneracies in a chaotic exciton-polariton billiard
NASA Astrophysics Data System (ADS)
Gao, T.; Estrecho, E.; Bliokh, K. Y.; Liew, T. C. H.; Fraser, M. D.; Brodbeck, S.; Kamp, M.; Schneider, C.; Höfling, S.; Yamamoto, Y.; Nori, F.; Kivshar, Y. S.; Truscott, A. G.; Dall, R. G.; Ostrovskaya, E. A.
2015-10-01
Exciton-polaritons are hybrid light-matter quasiparticles formed by strongly interacting photons and excitons (electron-hole pairs) in semiconductor microcavities. They have emerged as a robust solid-state platform for next-generation optoelectronic applications as well as for fundamental studies of quantum many-body physics. Importantly, exciton-polaritons are a profoundly open (that is, non-Hermitian) quantum system, which requires constant pumping of energy and continuously decays, releasing coherent radiation. Thus, the exciton-polaritons always exist in a balanced potential landscape of gain and loss. However, the inherent non-Hermitian nature of this potential has so far been largely ignored in exciton-polariton physics. Here we demonstrate that non-Hermiticity dramatically modifies the structure of modes and spectral degeneracies in exciton-polariton systems, and, therefore, will affect their quantum transport, localization and dynamical properties. Using a spatially structured optical pump, we create a chaotic exciton-polariton billiard--a two-dimensional area enclosed by a curved potential barrier. Eigenmodes of this billiard exhibit multiple non-Hermitian spectral degeneracies, known as exceptional points. Such points can cause remarkable wave phenomena, such as unidirectional transport, anomalous lasing/absorption and chiral modes. By varying parameters of the billiard, we observe crossing and anti-crossing of energy levels and reveal the non-trivial topological modal structure exclusive to non-Hermitian systems. We also observe mode switching and a topological Berry phase for a parameter loop encircling the exceptional point. Our findings pave the way to studies of non-Hermitian quantum dynamics of exciton-polaritons, which may uncover novel operating principles for polariton-based devices.
Observation of non-Hermitian degeneracies in a chaotic exciton-polariton billiard.
Gao, T; Estrecho, E; Bliokh, K Y; Liew, T C H; Fraser, M D; Brodbeck, S; Kamp, M; Schneider, C; Höfling, S; Yamamoto, Y; Nori, F; Kivshar, Y S; Truscott, A G; Dall, R G; Ostrovskaya, E A
2015-10-22
Exciton-polaritons are hybrid light-matter quasiparticles formed by strongly interacting photons and excitons (electron-hole pairs) in semiconductor microcavities. They have emerged as a robust solid-state platform for next-generation optoelectronic applications as well as for fundamental studies of quantum many-body physics. Importantly, exciton-polaritons are a profoundly open (that is, non-Hermitian) quantum system, which requires constant pumping of energy and continuously decays, releasing coherent radiation. Thus, the exciton-polaritons always exist in a balanced potential landscape of gain and loss. However, the inherent non-Hermitian nature of this potential has so far been largely ignored in exciton-polariton physics. Here we demonstrate that non-Hermiticity dramatically modifies the structure of modes and spectral degeneracies in exciton-polariton systems, and, therefore, will affect their quantum transport, localization and dynamical properties. Using a spatially structured optical pump, we create a chaotic exciton-polariton billiard--a two-dimensional area enclosed by a curved potential barrier. Eigenmodes of this billiard exhibit multiple non-Hermitian spectral degeneracies, known as exceptional points. Such points can cause remarkable wave phenomena, such as unidirectional transport, anomalous lasing/absorption and chiral modes. By varying parameters of the billiard, we observe crossing and anti-crossing of energy levels and reveal the non-trivial topological modal structure exclusive to non-Hermitian systems. We also observe mode switching and a topological Berry phase for a parameter loop encircling the exceptional point. Our findings pave the way to studies of non-Hermitian quantum dynamics of exciton-polaritons, which may uncover novel operating principles for polariton-based devices. PMID:26458102
NASA Astrophysics Data System (ADS)
Sun, Yi-Yang; Zhang, Shengbai
2016-07-01
Bulk black phosphorus has two optical phonon modes labeled as Ag2 and B2u, respectively, that are nearly degenerate in frequency. However, density functional theory calculations using local or semi-local functionals cannot reproduce this degeneracy. Here, we propose a hybrid functional approach aided by van der Waals (vdW) force fields, which can accurately describe the lattice dynamic and electronic properties of both bulk and few-layer black phosphorus (phosphorene). Using this approach we show that in bilayer phosphorene, the two Raman modes derived from the B2u and Ag2 modes could exhibit strong resonance as a result of the accidental degeneracy so that both modes could be observed in Raman experiment. Without the mode degeneracy, however, the Raman intensity of the B2u-derived mode would be too weak to be observed. We further show that the accidental degeneracy is correlated to the applied strain, which enables Raman spectroscopy to be a powerful tool for characterizing built-in strains in 2D materials, e.g., due to the interaction with substrates, which has emerged as an important issue in vdW epitaxy.
Sun, Yi-Yang; Zhang, Shengbai
2016-07-14
Bulk black phosphorus has two optical phonon modes labeled as Ag (2) and B2u, respectively, that are nearly degenerate in frequency. However, density functional theory calculations using local or semi-local functionals cannot reproduce this degeneracy. Here, we propose a hybrid functional approach aided by van der Waals (vdW) force fields, which can accurately describe the lattice dynamic and electronic properties of both bulk and few-layer black phosphorus (phosphorene). Using this approach we show that in bilayer phosphorene, the two Raman modes derived from the B2u and Ag (2) modes could exhibit strong resonance as a result of the accidental degeneracy so that both modes could be observed in Raman experiment. Without the mode degeneracy, however, the Raman intensity of the B2u-derived mode would be too weak to be observed. We further show that the accidental degeneracy is correlated to the applied strain, which enables Raman spectroscopy to be a powerful tool for characterizing built-in strains in 2D materials, e.g., due to the interaction with substrates, which has emerged as an important issue in vdW epitaxy. PMID:27421389
Employer Provisions for Parental Leave.
ERIC Educational Resources Information Center
Meisenheimer, Joseph R., II
1989-01-01
Slightly more than one-third of full-time employees in medium and large firms in private industry were covered by maternity- or paternity-leave policies; days off were usually leave without pay. (Author)
Transient potassium channels augment degeneracy in hippocampal active dendritic spectral tuning.
Rathour, Rahul Kumar; Malik, Ruchi; Narayanan, Rishikesh
2016-01-01
Hippocampal pyramidal neurons express an intraneuronal map of spectral tuning mediated by hyperpolarization-activated cyclic-nucleotide-gated nonspecific-cation channels. Modeling studies have predicted a critical regulatory role for A-type potassium (KA) channels towards augmenting functional robustness of this map. To test this, we performed patch-clamp recordings from soma and dendrites of rat hippocampal pyramidal neurons, and measured spectral tuning before and after blocking KA channels using two structurally distinct pharmacological agents. Consistent with computational predictions, we found that blocking KA channels resulted in a significant reduction in resonance frequency and significant increases in input resistance, impedance amplitude and action-potential firing frequency across the somato-apical trunk. Furthermore, across all measured locations, blocking KA channels enhanced temporal summation of postsynaptic potentials and critically altered the impedance phase profile, resulting in a significant reduction in total inductive phase. Finally, pair-wise correlations between intraneuronal percentage changes (after blocking KA channels) in different measurements were mostly weak, suggesting differential regulation of different physiological properties by KA channels. Our results unveil a pivotal role for fast transient channels in regulating theta-frequency spectral tuning and intrinsic phase response, and suggest that degeneracy with reference to several coexisting functional maps is mediated by cross-channel interactions across the active dendritic arbor. PMID:27094086
Transient potassium channels augment degeneracy in hippocampal active dendritic spectral tuning
Rathour, Rahul Kumar; Malik, Ruchi; Narayanan, Rishikesh
2016-01-01
Hippocampal pyramidal neurons express an intraneuronal map of spectral tuning mediated by hyperpolarization-activated cyclic-nucleotide-gated nonspecific-cation channels. Modeling studies have predicted a critical regulatory role for A-type potassium (KA) channels towards augmenting functional robustness of this map. To test this, we performed patch-clamp recordings from soma and dendrites of rat hippocampal pyramidal neurons, and measured spectral tuning before and after blocking KA channels using two structurally distinct pharmacological agents. Consistent with computational predictions, we found that blocking KA channels resulted in a significant reduction in resonance frequency and significant increases in input resistance, impedance amplitude and action-potential firing frequency across the somato-apical trunk. Furthermore, across all measured locations, blocking KA channels enhanced temporal summation of postsynaptic potentials and critically altered the impedance phase profile, resulting in a significant reduction in total inductive phase. Finally, pair-wise correlations between intraneuronal percentage changes (after blocking KA channels) in different measurements were mostly weak, suggesting differential regulation of different physiological properties by KA channels. Our results unveil a pivotal role for fast transient channels in regulating theta-frequency spectral tuning and intrinsic phase response, and suggest that degeneracy with reference to several coexisting functional maps is mediated by cross-channel interactions across the active dendritic arbor. PMID:27094086
Linear and nonlinear ion-acoustic waves in nonrelativistic quantum plasmas with arbitrary degeneracy
NASA Astrophysics Data System (ADS)
Haas, Fernando; Mahmood, Shahzad
2015-11-01
Linear and nonlinear ion-acoustic waves are studied in a fluid model for nonrelativistic, unmagnetized quantum plasma with electrons with an arbitrary degeneracy degree. The equation of state for electrons follows from a local Fermi-Dirac distribution function and applies equally well both to fully degenerate and classical, nondegenerate limits. Ions are assumed to be cold. Quantum diffraction effects through the Bohm potential are also taken into account. A general coupling parameter valid for dilute and dense plasmas is proposed. The linear dispersion relation of the ion-acoustic waves is obtained and the ion-acoustic speed is discussed for the limiting cases of extremely dense or dilute systems. In the long-wavelength limit, the results agree with quantum kinetic theory. Using the reductive perturbation method, the appropriate Korteweg-de Vries equation for weakly nonlinear solutions is obtained and the corresponding soliton propagation is analyzed. It is found that soliton hump and dip structures are formed depending on the value of the quantum parameter for the degenerate electrons, which affect the phase velocities in the dispersive medium.
NASA Astrophysics Data System (ADS)
Marquette, Ian
2015-04-01
Four new families of two-dimensional quantum superintegrable systems are constructed from k-step extension of the harmonic oscillator and the radial oscillator. Their wavefunctions are related with Hermite and Laguerre exceptional orthogonal polynomials (EOP) of type III. We show that ladder operators obtained from alternative construction based on combinations of supercharges in the Krein-Adler and Darboux Crum (or state deleting and creating) approaches can be used to generate a set of integrals of motion and a corresponding polynomial algebra that provides an algebraic derivation of the full spectrum and total number of degeneracies. Such derivation is based on finite dimensional unitary representations (unirreps) and doesn't work for integrals build from standard ladder operators in supersymmetric quantum mechanics (SUSYQM) as they contain singlets isolated from excited states. In this paper, we also rely on a novel approach to obtain the finite dimensional unirreps based on the action of the integrals of motion on the wavefunctions given in terms of these EOP. We compare the results with those obtained from the Daskaloyannis approach and the realizations in terms of deformed oscillator algebras for one of the new families in the case of 1-step extension. This communication is a review of recent works.
NASA Astrophysics Data System (ADS)
Delagrange, R.; Weil, R.; Kasumov, A.; Ferrier, M.; Bouchiat, H.; Deblock, R.
2016-05-01
In a π -Josephson junction, the supercurrent's sign is reversed due to the dephasing of superconducting pairs upon their traversal of the nonsuperconducting part. 0-π quantum transitions are extremely sensitive to electronic and magnetic correlations, providing powerful exploration tools of competing orders. In a quantum dot connected to superconducting reservoirs, the transition is governed by gate voltage. As shown recently, it can also be controlled by the superconducting phase in the case of strong competition between the superconducting proximity effect and Kondo correlations. We investigated here the current-phase relation in a clean carbon nanotube quantum dot, close to orbital degeneracy, in a regime of strong competition between local electronic correlations and superconducting proximity effect. We show that the nature of the transition depends crucially on the occupation and the width of the orbital levels, which determine their respective contribution to transport. When the transport of Cooper pairs takes place through only one of these levels, we find that the phase diagram of the phase-dependent 0-π transition is a universal characteristic of a discontinuous level-crossing quantum transition at zero temperature. In the case where the two levels are involved, the nanotube Josephson current exhibits a continuous 0-π transition, independent of the superconducting phase, revealing a different physical mechanism of the transition.
Absence of Hole Confinement in Transition Metal Oxides with Orbital Degeneracy
NASA Astrophysics Data System (ADS)
Daghofer, Maria; Wohlfeld, Krzysztof; Oles, Andrzej M.; Arrigoni, Enrico; Horsch, Peter
2008-03-01
The compounds with orbital degrees of freedom exhibit many possible scenarios for hole propagation which in most cases lead to hole localization [1]. Here we investigate the spectral properties of a hole moving in a two-dimensional Hubbard model for strongly correlated t2g electrons. Although superexchange interactions are Ising-like, a quasi-one-dimensional coherent hole motion arises due to effective three-site terms. This mechanism is fundamentally different either from the hole motion via quantum fluctuations in the conventional spin model with SU(2) symmetry or from the eg orbital model [2]. The present orbital model describes also propagation of a hole in some eg compounds [3], and we argue that orbital degeneracy alone does not lead to hole self-localization. [1] J. Zaanen and A.M. Ole's, Phys. Rev. B 48, 7197 (1993). [2] J. van den Brink, P. Horsch, and A.M. Ole's, Phys. Rev. Lett. 85, 5174 (2000). [3] M. Daghofer, A.M. Ole's, and W. von der Linden, Phys. Rev. B 70, 184430 (2004).
CCDM model with spatial curvature and the breaking of ``dark degeneracy''
NASA Astrophysics Data System (ADS)
Jesus, J. F.; Andrade-Oliveira, F.
2016-01-01
Creation of Cold Dark Matter (CCDM), in the context of Einstein Field Equations, leads to a negative creation pressure, which can be used to explain the accelerated expansion of the Universe. Recently, it has been shown that the dynamics of expansion of such models can not be distinguished from the concordance ΛCDM model, even at higher orders in the evolution of density perturbations, leading at the so called ``dark degeneracy''. However, depending on the form of the CDM creation rate, the inclusion of spatial curvature leads to a different behavior of CCDM when compared to ΛCDM, even at background level. With a simple form for the creation rate, namely, Γ∝1/H , we show that this model can be distinguished from ΛCDM, provided the Universe has some amount of spatial curvature. Observationally, however, the current limits on spatial flatness from CMB indicate that neither of the models are significantly favored against the other by current data, at least in the background level.
Semiclassical degeneracies and ordering for highly frustrated magnets in a field
NASA Astrophysics Data System (ADS)
Hassan, S. R.; Moessner, R.
2006-03-01
We discuss ground-state selection by quantum fluctuations in frustrated magnets in a strong magnetic field. We show that there exist dynamical symmetries—one a generalization of Henley’s gauge like symmetry for collinear spins, the other the quantum relict of non collinear weathervane modes—which ensure a partial survival of the classical degeneracies. We illustrate these for the case of the kagome magnet, where we find zero-point energy differences to be rather small everywhere except near the collinear “up-up-down” configurations, where there is rotational but not translational symmetry breaking. In the effective Hamiltonian, we demonstrate the presence of a term sensitive to a topological “flux.” We discuss the connection of such problems to gauge theories by casting the frustrated lattices as medial lattices of appropriately chosen simplex lattices, and in particular we show how the magnetic field can be used to tune the physical sector of the resulting gauge theories.
RESOLVING THE sin(I) DEGENERACY IN LOW-MASS MULTI-PLANET SYSTEMS
Batygin, Konstantin; Laughlin, Gregory
2011-04-01
Long-term orbital evolution of multi-planet systems under tidal dissipation often converges to a stationary state, known as the tidal fixed point. The fixed point is characterized by a lack of oscillations in the eccentricities and apsidal alignment among the orbits. Quantitatively, the nature of the fixed point is dictated by mutual interactions among the planets as well as non-Keplerian effects. We show that if a roughly coplanar system hosts a hot, sub-Saturn mass planet, and is tidally relaxed, separation of planet-planet interactions and non-Keplerian effects in the equations of motion leads to a direct determination of the true masses of the planets. Consequently, a 'snap-shot' observational determination of the orbital state resolves the sin(I) degeneracy and opens up a direct avenue toward identification of the true lowest-mass exoplanets detected. We present an approximate, as well as a general, mathematical framework for computation of the line-of-sight inclination of secular systems, and apply our models illustratively to the 61 Vir system. We conclude by discussing the observability of planetary systems to which our method is applicable and we set our analysis into a broader context by presenting a current summary of the various possibilities for determining the physical properties of planets from observations of their orbital states.
Cognitive Aging and Time Perception: Roles of Bayesian Optimization and Degeneracy.
Turgeon, Martine; Lustig, Cindy; Meck, Warren H
2016-01-01
This review outlines the basic psychological and neurobiological processes associated with age-related distortions in timing and time perception in the hundredths of milliseconds-to-minutes range. The difficulty in separating indirect effects of impairments in attention and memory from direct effects on timing mechanisms is addressed. The main premise is that normal aging is commonly associated with increased noise and temporal uncertainty as a result of impairments in attention and memory as well as the possible reduction in the accuracy and precision of a central timing mechanism supported by dopamine-glutamate interactions in cortico-striatal circuits. Pertinent to these findings, potential interventions that may reduce the likelihood of observing age-related declines in timing are discussed. Bayesian optimization models are able to account for the adaptive changes observed in time perception by assuming that older adults are more likely to base their temporal judgments on statistical inferences derived from multiple trials than on a single trial's clock reading, which is more susceptible to distortion. We propose that the timing functions assigned to the age-sensitive fronto-striatal network can be subserved by other neural networks typically associated with finely-tuned perceptuo-motor adjustments, through degeneracy principles (different structures serving a common function). PMID:27242513
Cognitive Aging and Time Perception: Roles of Bayesian Optimization and Degeneracy
Turgeon, Martine; Lustig, Cindy; Meck, Warren H.
2016-01-01
This review outlines the basic psychological and neurobiological processes associated with age-related distortions in timing and time perception in the hundredths of milliseconds-to-minutes range. The difficulty in separating indirect effects of impairments in attention and memory from direct effects on timing mechanisms is addressed. The main premise is that normal aging is commonly associated with increased noise and temporal uncertainty as a result of impairments in attention and memory as well as the possible reduction in the accuracy and precision of a central timing mechanism supported by dopamine-glutamate interactions in cortico-striatal circuits. Pertinent to these findings, potential interventions that may reduce the likelihood of observing age-related declines in timing are discussed. Bayesian optimization models are able to account for the adaptive changes observed in time perception by assuming that older adults are more likely to base their temporal judgments on statistical inferences derived from multiple trials than on a single trial’s clock reading, which is more susceptible to distortion. We propose that the timing functions assigned to the age-sensitive fronto-striatal network can be subserved by other neural networks typically associated with finely-tuned perceptuo-motor adjustments, through degeneracy principles (different structures serving a common function). PMID:27242513
Dawson, Maree
2012-01-01
Historians have focused on early twentieth-century positive eugenics in New Zealand In this article, I argue that the response came from a tradition of concern about heredity and white racial degeneracy, which extended beyond the British Empire. This article focuses on concerns about heredity at the Auckland Mental Hospital between 1850 and 1899, and contextualises these concerns in New Zealand mental hospital statistics from the late-nineteenth century. This article also considers Australasian, British, North and South American medical and immigration legislation history, and contrasts this with the legislation and medical discourses which formed part of a fear of heredity, racial degeneracy, immigration and mental illness in New Zealand. PMID:23066601
Parental Leave Policies and Parents’ Employment and Leave-Taking
Han, Wen-Jui; Ruhm, Christopher; Waldfogel, Jane
2009-01-01
We describe trends in maternal employment and leave-taking after birth of a newborn and analyze the extent to which these behaviors are influenced by parental leave policies. Data are from the June Current Population Survey (CPS) Fertility Supplements, merged with other months of the CPS, and cover the period 1987 to 1994. This time-span is one during which parental leave legislation expanded at both the state and federal level. We also provide the first comprehensive examination of employment and leave-taking by fathers of infants. Our main finding is that leave expansions are associated with increased leave-taking by both mothers and fathers. The magnitudes of the changes are small in absolute terms but large relative to the baseline for men and much greater for college-educated or married mothers than for their less-educated or single counterparts. PMID:19090048
Tieri, Paolo; Grignolio, Andrea; Zaikin, Alexey; Mishto, Michele; Remondini, Daniel; Castellani, Gastone C; Franceschi, Claudio
2010-01-01
Recently, the network paradigm, an application of graph theory to biology, has proven to be a powerful approach to gaining insights into biological complexity, and has catalyzed the advancement of systems biology. In this perspective and focusing on the immune system, we propose here a more comprehensive view to go beyond the concept of network. We start from the concept of degeneracy, one of the most prominent characteristic of biological complexity, defined as the ability of structurally different elements to perform the same function, and we show that degeneracy is highly intertwined with another recently-proposed organizational principle, i.e. 'bow tie architecture'. The simultaneous consideration of concepts such as degeneracy, bow tie architecture and network results in a powerful new interpretative tool that takes into account the constructive role of noise (stochastic fluctuations) and is able to grasp the major characteristics of biological complexity, i.e. the capacity to turn an apparently chaotic and highly dynamic set of signals into functional information. PMID:20701759
2010-01-01
Recently, the network paradigm, an application of graph theory to biology, has proven to be a powerful approach to gaining insights into biological complexity, and has catalyzed the advancement of systems biology. In this perspective and focusing on the immune system, we propose here a more comprehensive view to go beyond the concept of network. We start from the concept of degeneracy, one of the most prominent characteristic of biological complexity, defined as the ability of structurally different elements to perform the same function, and we show that degeneracy is highly intertwined with another recently-proposed organizational principle, i.e. 'bow tie architecture'. The simultaneous consideration of concepts such as degeneracy, bow tie architecture and network results in a powerful new interpretative tool that takes into account the constructive role of noise (stochastic fluctuations) and is able to grasp the major characteristics of biological complexity, i.e. the capacity to turn an apparently chaotic and highly dynamic set of signals into functional information. PMID:20701759
NASA Astrophysics Data System (ADS)
Cuntz, M.; Ogée, J.; Farquhar, G. D.; Cernusak, L. A.; Peylin, P.; Bariac, T.
2007-12-01
Leaf water isotope enrichment is a cornerstone of a variety of isotopic applications. It imprints on different substances such as atmospheric CO2, O2, and plant organic matter. But different applications use enrichment in different parts of the leaf and weighted by different fluxes. For example, leaf organic matter is determined by the assimilation-weighted average bulk water enrichment. Atmospheric CO2 and O2 are determined by the enrichment near the evaporating sites, either weighted by the one-way CO2 flux from the stomata to the atmosphere or by electron transport, resp. These applications of leaf water enrichment are used from the leaf level up to global scales. It is therefore essential to understand the time course of leaf water enrichment at both the evaporating sites and in the mesophyll but also to asses the suitability of simple models such as the Craig & Gordon (1965) steady-state prediction or the Dongmann et al. (1974) non-steady-state model. We describe here advection and diffusion of water isotopologues in leaves in the non-steady state. We first show how this relates to earlier non-steady state bulk leaf water enrichment models. The adv.-diff. model compares very well with observations of bulk mesophyll water during the whole diel cycle. It compares well with the enrichment at the evaporative sites during the day but shows some deviations at night. It is clear that night-time stomatal conductance should be measured in the future. However, varying mesophyll water volume did not seem critical for a good prediction. In addition, observations of single diurnal cycles do not constrain the effective length in the mesophyll. Finally, we show when simpler models of leaf water enrichment are suitable for applications of leaf water isotopes once weighted with the appropriate gas exchange flux. We then present a two-dimensional adv.-diff. description of leaf water enrichment along monocot leaves. The model reproduces well all published measurements along
5 CFR 630.1205 - Intermittent leave or reduced leave schedule.
Code of Federal Regulations, 2012 CFR
2012-01-01
... REGULATIONS ABSENCE AND LEAVE Family and Medical Leave § 630.1205 Intermittent leave or reduced leave schedule... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Intermittent leave or reduced leave... reduced leave schedule unless the employee and the agency agree to do so. (b) Leave under §...
5 CFR 630.1204 - Intermittent leave or reduced leave schedule.
Code of Federal Regulations, 2011 CFR
2011-01-01
... REGULATIONS ABSENCE AND LEAVE Family and Medical Leave § 630.1204 Intermittent leave or reduced leave schedule... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Intermittent leave or reduced leave... reduced leave schedule unless the employee and the agency agree to do so. (b) Leave under § 630.1203(a)...
5 CFR 630.1205 - Intermittent leave or reduced leave schedule.
Code of Federal Regulations, 2014 CFR
2014-01-01
... REGULATIONS ABSENCE AND LEAVE Family and Medical Leave § 630.1205 Intermittent leave or reduced leave schedule... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Intermittent leave or reduced leave... reduced leave schedule unless the employee and the agency agree to do so. (b) Leave under §...
5 CFR 630.1205 - Intermittent leave or reduced leave schedule.
Code of Federal Regulations, 2013 CFR
2013-01-01
... REGULATIONS ABSENCE AND LEAVE Family and Medical Leave § 630.1205 Intermittent leave or reduced leave schedule... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Intermittent leave or reduced leave... reduced leave schedule unless the employee and the agency agree to do so. (b) Leave under §...
5 CFR 630.1204 - Intermittent leave or reduced leave schedule.
Code of Federal Regulations, 2010 CFR
2010-01-01
... REGULATIONS ABSENCE AND LEAVE Family and Medical Leave § 630.1204 Intermittent leave or reduced leave schedule... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Intermittent leave or reduced leave... reduced leave schedule unless the employee and the agency agree to do so. (b) Leave under § 630.1203(a)...
NASA Astrophysics Data System (ADS)
Finley, James P.; Chaudhuri, Rajat K.; Freed, Karl F.
1996-07-01
High-order multireference perturbation theory is applied to the 1S states of the beryllium atom using a reference (model) space composed of the \\|1s22s2> and the \\|1s22p2> configuration-state functions (CSF's), a system that is known to yield divergent expansions using Mo/ller-Plesset and Epstein-Nesbet partitioning methods. Computations of the eigenvalues are made through 40th order using forced degeneracy (FD) partitioning and the recently introduced optimization (OPT) partitioning. The former forces the 2s and 2p orbitals to be degenerate in zeroth order, while the latter chooses optimal zeroth-order energies of the (few) most important states. Our methodology employs simple models for understanding and suggesting remedies for unsuitable choices of reference spaces and partitioning methods. By examining a two-state model composed of only the \\|1s22p2> and \\|1s22s3s> states of the beryllium atom, it is demonstrated that the full computation with 1323 CSF's can converge only if the zeroth-order energy of the \\|1s22s3s> Rydberg state from the orthogonal space lies below the zeroth-order energy of the \\|1s22p2> CSF from the reference space. Thus convergence in this case requires a zeroth-order spectral overlap between the orthogonal and reference spaces. The FD partitioning is not capable of generating this type of spectral overlap and thus yields a divergent expansion. However, the expansion is actually asymptotically convergent, with divergent behavior not displayed until the 11th order because the \\|1s22s3s> Rydberg state is only weakly coupled with the \\|1s22p2> CSF and because these states are energetically well separated in zeroth order. The OPT partitioning chooses the correct zeroth-order energy ordering and thus yields a convergent expansion that is also very accurate in low orders compared to the exact solution within the basis.
Orzechowski, Sławomir
2008-01-01
Starch is the most abundant storage carbohydrate produced in plants. The initiation of transitory starch synthesis and degradation in plastids depends mainly on diurnal cycle, post-translational regulation of enzyme activity and starch phosphorylation. For the proper structure of starch granule the activities of all starch synthase isoenzymes, branching enzymes and debranching enzymes are needed. The intensity of starch biosynthesis depends mainly on the activity of AGPase (adenosine 5'-diphosphate glucose pyrophosphorylase). The key enzymes in starch degradation are beta-amylase, isoamylase 3 and disproportionating enzyme. However, it should be underlined that there are some crucial differences in starch metabolism between heterotrophic and autotrophic tissues, e.g. is the ability to build multiprotein complexes responsible for biosynthesis and degradation of starch granules in chloroplasts. The observed huge progress in understanding of starch metabolism was possible mainly due to analyses of the complete Arabidopsis and rice genomes and of numerous mutants with altered starch metabolism in leaves. The aim of this paper is to review current knowledge on transient starch metabolism in higher plants. PMID:18787712
Probing Radial age/metallicity degeneracy in early-type galaxies
NASA Astrophysics Data System (ADS)
Silva, David R.; Elston, Richard
1994-06-01
It has been generally concluded that the optical broad band color and line index gradients observed in early-type galaxies are driven by metallicity. Yet, this conclusion remains uncertain due to the age/metallicity degeneracy inherent in most optical data. Furthermore, optical broad-band colors are susceptible to reddening in the presence of dust. Near-infrared colors, on the other hand, are significantly less age sensitive than optical colors in old stellar populations and are much less affected by dust. In principle, the combination of optical and near-IR data should provide less ambivalent age and metallicity discrimination than using optical or near-IR data alone. To investigate this possibility, near-IR images of early-type galaxies with significant U-R gradients have been measured. Comparison of the optical and near-IR results leads to the primary conclusion that broad-band optical and near-IR gradients are not tracing metallicity in concert but are affected by different astrophysical parameters. Three general possibilites are discussed: reddening, radial age gradients, and differing metallicity sensitivities. Proving the absence or presence of significant reddening is difficult from broad-band colors alone. In the absence of reddening, the optical color gradients would suggest that age decreases wit radius, leading to somewhat contrived evolution scenarios. Alternatively, it is proposed that the optical color gradients may be tracing light element (e.g. CNO) abundances while the near-IR gradients are tracing Fe- peak element abundances. This scenario leads to the conclusion that many of these galaxies have enhanced nuclear (light/FE) ratios, consistent with the recently published studies of nuclear line indices in these galaxies. Given the quality of the current available data, these hypotheses remain somewhat unconstrained. Nevertheless, this study reinforces the necessity of obtaining data over a long spectral baseline to properly interpret the ensemble
Revising the solution of the neutrino oscillation parameter degeneracies at neutrino factories
Gago, A. M.; Jones Perez, J.
2007-02-01
In the context of neutrino factories, we review the solution of the degeneracies in the neutrino oscillation parameters. In particular, we have set limits to sin{sup 2}2{theta}{sub 13} in order to accomplish the unambiguous determination of {theta}{sub 23} and {delta}. We have performed two different analysis. In the first, at a baseline of 3000 km, we simulate a measurement of the channels {nu}{sub e}{yields}{nu}{sub {mu}}, {nu}{sub e}{yields}{nu}{sub {tau}}, and {nu}{sub {mu}}{yields}{nu}{sub {mu}}, combined with their respective conjugate ones, with a muon energy of 50 GeV and a running time of five years. In the second, we merge the simulated data obtained at L=3000 km with the measurement of {nu}{sub e}{yields}{nu}{sub {mu}} channel at 7250 km, the so-called 'magic baseline.' In both cases, we have studied the impact of varying the {nu}{sub {tau}} detector efficiency-mass product ({epsilon}{sub {nu}{tau}xM{tau}}), at 3000 km, keeping unchanged the {nu}{sub {mu}} detector mass and its efficiency. At L=3000 km, we found the existence of degenerate zones, that correspond to values of {theta}{sub 13}, which are equal or almost equal to the true ones. These zones are extremely difficult to discard, even when we increase the number of events. However, in the second scenario, this difficulty is overcome, demonstrating the relevance of the 'magic baseline'. From this scenario, the best limits of sin{sup 2}2{theta}{sub 13}, reached at 3{sigma}, for sin{sup 2}2{theta}{sub 23}=0.95, 0.975, and 0.99 are: 0.008, 0.015, and 0.045, respectively, obtained at {delta}=0, and considering ({epsilon}{sub {nu}{tau}xM{tau}}){approx_equal}125, which is 5 times the initial efficiency-mass combination.
29 CFR 825.202 - Intermittent leave or reduced leave schedule.
Code of Federal Regulations, 2011 CFR
2011-07-01
... LABOR OTHER LAWS THE FAMILY AND MEDICAL LEAVE ACT OF 1993 Employee Leave Entitlements Under the Family and Medical Leave Act § 825.202 Intermittent leave or reduced leave schedule. (a) Definition. FMLA... 29 Labor 3 2011-07-01 2011-07-01 false Intermittent leave or reduced leave schedule....
5 CFR 630.1003 - Establishing leave banks and leave bank boards.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Establishing leave banks and leave bank... REGULATIONS ABSENCE AND LEAVE Voluntary Leave Bank Program § 630.1003 Establishing leave banks and leave bank boards. (a) Each agency that participates in the voluntary leave bank program shall, in accordance...
5 CFR 630.1003 - Establishing leave banks and leave bank boards.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Establishing leave banks and leave bank... REGULATIONS ABSENCE AND LEAVE Voluntary Leave Bank Program § 630.1003 Establishing leave banks and leave bank boards. (a) Each agency that participates in the voluntary leave bank program shall, in accordance...
5 CFR 630.1003 - Establishing leave banks and leave bank boards.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Establishing leave banks and leave bank... REGULATIONS ABSENCE AND LEAVE Voluntary Leave Bank Program § 630.1003 Establishing leave banks and leave bank boards. (a) Each agency that participates in the voluntary leave bank program shall, in accordance...
5 CFR 630.1003 - Establishing leave banks and leave bank boards.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Establishing leave banks and leave bank... REGULATIONS ABSENCE AND LEAVE Voluntary Leave Bank Program § 630.1003 Establishing leave banks and leave bank boards. (a) Each agency that participates in the voluntary leave bank program shall, in accordance...
5 CFR 630.1003 - Establishing leave banks and leave bank boards.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Establishing leave banks and leave bank... REGULATIONS ABSENCE AND LEAVE Voluntary Leave Bank Program § 630.1003 Establishing leave banks and leave bank boards. (a) Each agency that participates in the voluntary leave bank program shall, in accordance...
NASA Astrophysics Data System (ADS)
Guo, Xiaoyang; Leng, Yuxin; Li, Yanyan; Li, Wenkai; Lu, Xiaoming; Xu, Yi; Li, Ruxin
2016-07-01
Broadband optical parametric amplification (OPA) in the near-infrared region (1.3-1.8 μm) is demonstrated in YCOB crystal pumped by 1 kHz Ti:sapphire based femtosecond laser at near critical wavelength degeneracy phase matching condition at first time. The gain bandwidth is closed to BIBO or BBO crystal OPA gain bandwidth. The energy obtained with 3.5 mm-thick YCOB reached 20 μJ with RMS 1.9%. After second harmonic generation, 17.6 fs pulse is obtained, and the pulse compressibility is demonstrated.
Tsai, V.C.
2010-01-01
Recent derivations have shown that when noise in a physical system has its energy equipartitioned into the modes of the system, there is a convenient relationship between the cross correlation of time-series recorded at two points and the Green's function of the system. Here, we show that even when energy is not fully equipartitioned and modes are allowed to be degenerate, a similar (though less general) property holds for equations with wave equation structure. This property can be used to understand why certain seismic noise correlation measurements are successful despite known degeneracy and lack of equipartition on the Earth. No claim to original US government works Journal compilation ?? 2010 RAS.
Organ-Level Analysis of Idioblast Patterning in Egeria densa Planch. Leaves
Hara, Takuya; Kobayashi, Emi; Ohtsubo, Kohei; Kumada, Shogo; Kanazawa, Mikako; Abe, Tomoko; Itoh, Ryuuichi D.; Fujiwara, Makoto T.
2015-01-01
Leaf tissues of plants usually contain several types of idioblasts, defined as specialized cells whose shape and contents differ from the surrounding homogeneous cells. The spatial patterning of idioblasts, particularly of trichomes and guard cells, across the leaf epidermis has received considerable attention as it offers a useful biological model for studying the intercellular regulation of cell fate and patterning. Excretory idioblasts in the leaves of the aquatic monocotyledonous plant Egeria densa produced light blue autofluorescence when irradiated with ultraviolet light. The use of epifluorescence microscopy to detect this autofluorescence provided a simple and convenient method for detecting excretory idioblasts and allowed tracking of those cells across the leaf surfaces, enabling quantitative measurement of the clustering and spacing patterns of idioblasts at the whole leaf level. Occurrence of idioblasts was coordinated along the proximal–distal, medial–lateral, and adaxial–abaxial axes, producing a recognizable consensus spatial pattern of idioblast formation among fully expanded leaves. Idioblast clusters, which comprised up to nine cells aligned along the proximal–distal axis, showed no positional bias or regularity in idioblast-forming areas when compared with singlet idioblasts. Up to 75% of idioblasts existed as clusters on every leaf side examined. The idioblast-forming areas varied between leaves, implying phenotypic plasticity. Furthermore, in young expanding leaves, autofluorescence was occasionally detected in a single giant vesicle or else in one or more small vesicles, which eventually grew to occupy a large portion of the idioblast volume as a central vacuole. Differentiation of vacuoles by accumulating the fluorescence substance might be an integral part of idioblast differentiation. Red autofluorescence from chloroplasts was not detected in idioblasts of young expanding leaves, suggesting idioblast differentiation involves an
Key Obama officials leave administration
NASA Astrophysics Data System (ADS)
Showstack, Randy
2013-01-01
Secretary of the Interior Ken Salazar is one of the latest members of the Obama administration to announce that he is leaving his position near the start of President Obama's second term in office. Salazar, who has served as interior secretary since January 2009, intends to leave the department by the end of March, the department noted on 16 January. Salazar joins a number of other key officials who are planning to leave the administration. They include Environmental Protection Agency administrator Lisa Jackson, National Oceanic and Atmospheric Administration administrator Jane Lubchenco, and U.S. Geological Survey director Marcia McNutt.
Barkeshli, Maissam
2016-08-26
It has been recently shown that non-Abelian defects with localized parafermion zero modes can arise in conventional Abelian fractional quantum Hall (FQH) states. Here we propose an alternate route to creating, manipulating, and measuring topologically protected degeneracies in bilayer FQH states coupled to superconductors, without the creation of localized parafermion zero modes. We focus mainly on electron-hole bilayers, with a ±1/3 Laughlin FQH state in each layer, with boundaries that are proximity coupled to a superconductor. We show that the superconductor induces charge 2e/3 quasiparticle-pair condensation at each boundary of the FQH state, and that this leads to (i) topologically protected degeneracies that can be measured through charge sensing experiments and (ii) a fractional charge 2e/3 ac Josephson effect. We demonstrate that an analog of non-Abelian braiding is possible, despite the absence of a localized zero mode. We discuss several practical advantages of this proposal over previous work, and also several generalizations. PMID:27610873
Code of Federal Regulations, 2013 CFR
2013-10-01
... (7) days. (3) Annual leave shall not exceed thirty (30) days. (4) Christmas and Easter leave shall..., as authorized by the school, not to exceed four (4) months. (2) Christmas and Easter leave and...
Code of Federal Regulations, 2012 CFR
2012-10-01
... (7) days. (3) Annual leave shall not exceed thirty (30) days. (4) Christmas and Easter leave shall..., as authorized by the school, not to exceed four (4) months. (2) Christmas and Easter leave and...
Code of Federal Regulations, 2010 CFR
2010-10-01
... (7) days. (3) Annual leave shall not exceed thirty (30) days. (4) Christmas and Easter leave shall..., as authorized by the school, not to exceed four (4) months. (2) Christmas and Easter leave and...
Code of Federal Regulations, 2014 CFR
2014-10-01
... (7) days. (3) Annual leave shall not exceed thirty (30) days. (4) Christmas and Easter leave shall..., as authorized by the school, not to exceed four (4) months. (2) Christmas and Easter leave and...
Code of Federal Regulations, 2011 CFR
2011-10-01
... (7) days. (3) Annual leave shall not exceed thirty (30) days. (4) Christmas and Easter leave shall..., as authorized by the school, not to exceed four (4) months. (2) Christmas and Easter leave and...
NASA Astrophysics Data System (ADS)
Han, C.; Udalski, A.; Lee, C.-U.; Gould, A.; Bozza, V.; Szymański, M. K.; Soszyński, I.; Skowron, J.; Mróz, P.; Poleski, R.; Pietrukowicz, P.; Kozłowski, S.; Ulaczyk, K.; Wyrzykowski, Ł.; Pawlak, M.; The OGLE Collaboration; Albrow, M. D.; Chung, S.-J.; Kim, S.-L.; Cha, S.-M.; Jung, Y. K.; Kim, D.-J.; Lee, Y.; Park, B.-G.; Ryu, Y.-H.; Shin, I.-G.; Yee, J. C.; The KMTNet Collaboration
2016-08-01
In this paper, we demonstrate the severity of the degeneracy between the microlens-parallax and lens-orbital effects by presenting the analysis of the gravitational binary-lens event OGLE-2015-BLG-0768. Despite the obvious deviation from the model based on the linear observer motion and the static binary, it is found that the residual can be almost equally well explained by either the parallactic motion of the Earth or the rotation of the binary-lens axis, resulting in the severe degeneracy between the two effects. We show that the degeneracy can be readily resolved with the additional data provided by space-based microlens parallax observations. By enabling us to distinguish between the two higher-order effects, space-based microlens parallax observations will not only make it possible to accurately determine the physical lens parameters but also to further constrain the orbital parameters of binary lenses.
Klassen, Joel; Wen, Xiao-Gang
2015-10-14
We study a chain of ferromagnetic sites, ie nano-particles, molecules or atoms, on a substrate of fully gapped superconductors. We find that under quite realistic conditions, the fermion-number-parity symmetry Z₂(f) can spontaneously break. In other words, such a chain can realize a 1 + 1D fermionic topologically ordered state and the corresponding two-fold topological degeneracy on an open chain. Such a topological degeneracy becomes the so called Majorana zero mode in the non-interacting limit. PMID:26401725
NASA Astrophysics Data System (ADS)
Chen, Y. F.; Tung, J. C.; Chiang, P. Y.; Liang, H. C.; Huang, K. F.
2013-07-01
We employ the inhomogeneous Helmholtz equation to explore the influence of the fractional degeneracy and the pump distribution on the resonant lasing mode. Theoretical analyses clearly reveal the relationship between the fractional degeneracy and the emergence of the ray-wave duality. Furthermore, we perform thorough laser experiments to confirm the theoretical exploration that the resonant modes near the degenerate cavities are well localized on the ray trajectories under the condition of the off-axis pumping. We also exploit the derived wave functions to calculate the resonant strengths that can noticeably manifest the enhancements of the output powers in the degenerate cavities.
75 FR 70845 - Absence and Leave; Qualifying Exigency Leave
Federal Register 2010, 2011, 2012, 2013, 2014
2010-11-19
... NDAA legislation. DOL issued its final regulations on November 17, 2008, (73 FR 67934) to implement the... proposed FMLA regulations on August 26, 2009, (74 FR 43064, at http://edocket.access.gpo.gov/2009/pdf/E9... leave may be found in the DOL proposed regulations published on February 11, 2008, at 73 FR 7876...
75 FR 75363 - Absence and Leave; Sick Leave
Federal Register 2010, 2011, 2012, 2013, 2014
2010-12-03
... regulations are in response to only a portion of OPM's proposed regulations (74 FR 43064) issued on August 26... regulations (75 FR 33491) amending the definition of family member for sick leave purposes to now cover..., guardianship, and other relationships. The final regulations are available at...
Bhajun, Ricky; Guyon, Laurent; Gidrol, Xavier
2016-08-01
Modularity, feedback control, functional redundancy and bowtie architecture have been proposed as key factors that confer robustness to complex biological systems. MicroRNAs (miRNAs) are highly conserved but functionally dispensable. These antinomic properties suggest that miRNAs fine-tune gene expression rather than act as genetic switches. We synthesize published and unpublished data and hypothesize that miRNA pluripotentiality acts to buffer gene expression, while miRNA degeneracy tunes the expression of targets, thus providing robustness to gene expression networks. Furthermore, we propose a Lavallière-tie architecture by integrating signal transduction, miRNAs and protein expression data to model complex gene expression networks. PMID:27038488
NASA Astrophysics Data System (ADS)
Xu, Lin; Wang, Hai-Xiao; Xu, Ya-Dong; Chen, Huan-Yang; Jiang, Jian-Hua
2016-08-01
A simple core-shell two-dimensional photonic crystal is studied where the triangle lattice symmetry and $C_{6v}$ rotation symmetry leads to rich physics in the study of accidental degeneracy's in photonic bands. We systematically evaluate different types of accidental nodal points, depending on the dispersions around them and their topological properties, when the geometry and permittivity are continuously changed. These accidental nodal points can be the critical states lying between a topological phase and a normal phase and are thus important for the study of topological photonic states. In time-reversal systems, this leads to the photonic quantum spin Hall insulator where the spin is defined upon the orbital angular momentum for transverse-magnetic polarization. We study the topological phase transition as well as the properties of the edge and bulk states and their application potentials in optics.
González, José; Molina, Rafael A
2016-04-15
We investigate the development of novel surface states when 3D Dirac or Weyl semimetals are placed under circularly polarized electromagnetic radiation. We find that the hybridization between inverted Floquet bands opens, in general, a gap, which closes at so-called exceptional points found for complex values of the momentum. This corresponds to the appearance of midgap surface states in the form of evanescent waves decaying from the surface exposed to the radiation. We observe a phenomenon reminiscent of Landau quantization by which the midgap surface states get a large degeneracy proportional to the radiation flux traversing the surface of the semimetal. We show that all of these surface states carry angular current, leading to an angular modulation of their charge that rotates with the same frequency of the radiation, which should manifest in the observation of a macroscopic chiral current in the irradiated surface. PMID:27127980
Sarantopoulos, A; Ferreiro-Vila, E; Pardo, V; Magén, C; Aguirre, M H; Rivadulla, F
2015-10-16
We report thermoelectric power experiments in e-doped thin films of SrTiO3 (STO) which demonstrate that the electronic band degeneracy can be lifted through defect management during growth. We show that even small amounts of cationic vacancies, combined with epitaxial stress, produce a homogeneous tetragonal distortion of the films, resulting in a Kondo-like resistance upturn at low temperature, large anisotropic magnetoresistance, and nonlinear Hall effect. Ab initio calculations confirm a different occupation of each band depending on the degree of tetragonal distortion. The phenomenology reported in this Letter for tetragonally distorted e-doped STO thin films, is similar to that observed in LaAlO3/STO interfaces and magnetic STO quantum wells. PMID:26550891
NASA Astrophysics Data System (ADS)
González, José; Molina, Rafael A.
2016-04-01
We investigate the development of novel surface states when 3D Dirac or Weyl semimetals are placed under circularly polarized electromagnetic radiation. We find that the hybridization between inverted Floquet bands opens, in general, a gap, which closes at so-called exceptional points found for complex values of the momentum. This corresponds to the appearance of midgap surface states in the form of evanescent waves decaying from the surface exposed to the radiation. We observe a phenomenon reminiscent of Landau quantization by which the midgap surface states get a large degeneracy proportional to the radiation flux traversing the surface of the semimetal. We show that all of these surface states carry angular current, leading to an angular modulation of their charge that rotates with the same frequency of the radiation, which should manifest in the observation of a macroscopic chiral current in the irradiated surface.
Chatterjee, Suchetana; Nguyen, My L.; Myers, Adam D.; Zheng, Zheng
2013-12-20
Recent work on quasar clustering suggests a degeneracy in the halo occupation distribution constrained from two-point correlation functions. To break this degeneracy, we make the first empirical measurement of the mean occupation function (MOF) of quasars at z ∼ 0.2 by matching quasar positions with groups and clusters identified in the MaxBCG sample. We fit two models to the MOF, a power law and a four-parameter model. The number distribution of quasars in host halos is close to Poisson, and the slopes of the MOF obtained from our best-fit models (for the power-law case) favor an MOF that monotonically increases with halo mass. The best-fit slopes are 0.53 ± 0.04 and 1.03 ± 1.12 for the power-law model and the four-parameter model, respectively. We measure the radial distribution of quasars within dark matter halos and find it to be adequately described by a power law with a slope –2.3 ± 0.4. We measure the conditional luminosity function (CLF) of quasars and show that there is no evidence that quasar luminosity depends on host halo mass, similar to the inferences drawn from clustering measurements. We also measure the conditional black hole mass function (CMF) of our quasars. Although the results are consistent with no dependence on halo mass, we observe a slight indication of downsizing of the black hole mass function. The lack of halo mass dependence in the CLF and CMF shows that quasars residing in galaxy clusters have characteristic luminosity and black hole mass scales.
The mass-sheet degeneracy and time-delay cosmography: analysis of the strong lens RXJ1131-1231
NASA Astrophysics Data System (ADS)
Birrer, Simon; Amara, Adam; Refregier, Alexandre
2016-08-01
We present extended modelling of the strong lens system RXJ1131-1231 with archival data in two HST bands in combination with existing line-of-sight contribution and velocity dispersion estimates. Our focus is on source size and its influence on time-delay cosmography. We therefore examine the impact of mass-sheet degeneracy and especially the degeneracy pointed out by Schneider & Sluse (2013) [1] using the source reconstruction scale. We also extend on previous work by further exploring the effects of priors on the kinematics of the lens and the external convergence in the environment of the lensing system. Our results coming from RXJ1131-1231 are given in a simple analytic form so that they can be easily combined with constraints coming from other cosmological probes. We find that the choice of priors on lens model parameters and source size are subdominant for the statistical errors for H0 measurements of this systems. The choice of prior for the source is sub-dominant at present (2% uncertainty on H0) but may be relevant for future studies. More importantly, we find that the priors on the kinematic anisotropy of the lens galaxy have a significant impact on our cosmological inference. When incorporating all the above modeling uncertainties, we find H0 = 86.6+6.8‑6.9 km s‑1 Mpc‑1, when using kinematic priors similar to other studies. When we use a different kinematic prior motivated by Barnabè et al. (2012) [2] but covering the same anisotropic range, we find H0 = 74.5+8.0‑7.8 km s‑1 Mpc‑1. This means that the choice of kinematic modeling and priors have a significant impact on cosmographic inferences. The way forward is either to get better velocity dispersion measures which would down weight the impact of the priors or to construct physically motivated priors for the velocity dispersion model.
Gurden, Dean
2016-08-10
'Leaving a job is never a decision you should take lightly,' says Nick Simpson, CEO of health recruitment agency MSI Group. 'Every nursing professional has things about their job they find frustrating and daily tasks they may not necessarily enjoy doing, but it's important to consider the positive aspects of your current role before you make a decision.' PMID:27507390
Technology Transfer Automated Retrieval System (TEKTRAN)
Burning fossil fuels and land use changes such as deforestation and urbanization have led to a dramatic rise in the concentration of carbon dioxide (CO2) in the atmosphere since the onset of the Industrial Revolution. The highly dilute CO2 from the atmosphere enters plant leaves where it is concentr...
5 CFR 630.1004 - Application to become a leave contributor and leave bank member.
Code of Federal Regulations, 2010 CFR
2010-01-01
... to the leave bank board to become a leave contributor. The application shall specify the number of hours of annual leave to be contributed and any other information the leave bank board may reasonably... section during an open enrollment period established by the leave bank board under paragraphs (d) and...
Carnivorous leaves from Baltic amber
Sadowski, Eva-Maria; Seyfullah, Leyla J.; Sadowski, Friederike; Fleischmann, Andreas; Behling, Hermann; Schmidt, Alexander R.
2015-01-01
The fossil record of carnivorous plants is very scarce and macrofossil evidence has been restricted to seeds of the extant aquatic genus Aldrovanda of the Droseraceae family. No case of carnivorous plant traps has so far been reported from the fossil record. Here, we present two angiosperm leaves enclosed in a piece of Eocene Baltic amber that share relevant morphological features with extant Roridulaceae, a carnivorous plant family that is today endemic to the Cape flora of South Africa. Modern Roridula species are unique among carnivorous plants as they digest prey in a complex mutualistic association in which the prey-derived nutrient uptake depends on heteropteran insects. As in extant Roridula, the fossil leaves possess two types of plant trichomes, including unicellular hairs and five size classes of multicellular stalked glands (or tentacles) with an apical pore. The apices of the narrow and perfectly tapered fossil leaves end in a single tentacle, as in both modern Roridula species. The glandular hairs of the fossils are restricted to the leaf margins and to the abaxial lamina, as in extant Roridula gorgonias. Our discovery supports current molecular age estimates for Roridulaceae and suggests a wide Eocene distribution of roridulid plants. PMID:25453067
Carnivorous leaves from Baltic amber.
Sadowski, Eva-Maria; Seyfullah, Leyla J; Sadowski, Friederike; Fleischmann, Andreas; Behling, Hermann; Schmidt, Alexander R
2015-01-01
The fossil record of carnivorous plants is very scarce and macrofossil evidence has been restricted to seeds of the extant aquatic genus Aldrovanda of the Droseraceae family. No case of carnivorous plant traps has so far been reported from the fossil record. Here, we present two angiosperm leaves enclosed in a piece of Eocene Baltic amber that share relevant morphological features with extant Roridulaceae, a carnivorous plant family that is today endemic to the Cape flora of South Africa. Modern Roridula species are unique among carnivorous plants as they digest prey in a complex mutualistic association in which the prey-derived nutrient uptake depends on heteropteran insects. As in extant Roridula, the fossil leaves possess two types of plant trichomes, including unicellular hairs and five size classes of multicellular stalked glands (or tentacles) with an apical pore. The apices of the narrow and perfectly tapered fossil leaves end in a single tentacle, as in both modern Roridula species. The glandular hairs of the fossils are restricted to the leaf margins and to the abaxial lamina, as in extant Roridula gorgonias. Our discovery supports current molecular age estimates for Roridulaceae and suggests a wide Eocene distribution of roridulid plants. PMID:25453067
NASA Astrophysics Data System (ADS)
Dutton, Aaron A.; Macciò, Andrea V.; Mendel, J. Trevor; Simard, Luc
2013-07-01
We use the relations between aperture stellar velocity dispersion (σap), stellar mass (MSPS) and galaxy size (Re) for a sample of ˜150 000 early-type galaxies from Sloan Digital Sky Survey/DR7 to place constraints on the stellar initial mass function (IMF) and dark halo response to galaxy formation. We build λ cold dark matter-based mass models that reproduce, by construction, the relations between galaxy size, light concentration and stellar mass, and use the spherical Jeans equations to predict σap. Given our model assumptions (including those in the stellar population synthesis models), we find that reproducing the median σap versus MSPS relation is not possible with both a universal IMF and a universal dark halo response. Significant departures from a universal IMF and/or dark halo response are required, but there is a degeneracy between these two solutions. We show that this degeneracy can be broken using the strength of the correlation between residuals of the velocity-mass (Δlog σap) and size-mass (Δlog Re) relations. The slope of this correlation, ∂VR ≡ Δlog σap/Δlog Re, varies systematically with galaxy mass from ∂VR ≃ -0.45 at MSPS ˜ 1010 M⊙ to ∂VR ≃ -0.15 at MSPS ˜ 1011.6 M⊙. The virial Fundamental Plane (FP) has ∂VR = -1/2, and thus we find that the tilt of the observed FP is mass dependent. Reproducing this tilt requires both a non-universal IMF and a non-universal halo response. Our best model has mass-follows-light at low masses (MSPS ≲ 1011.2 M⊙) and unmodified Navarro, Frenk and White haloes at MSPS ˜ 1011.5 M⊙. The stellar masses imply a mass-dependent IMF which is `lighter' than Salpeter at low masses and `heavier' than Salpeter at high masses.
Leaving the hospital - your discharge plan
... patientinstructions/000867.htm Leaving the hospital - your discharge plan To use the sharing features on this page, ... once you leave. This is called a discharge plan. Your health care providers at the hospital will ...
Uvarov, Mikhail N; Kulik, Leonid V; Pichugina, Tatiana I; Dzuba, Sergei A
2011-05-01
X-band echo-detected electron paramagnetic resonance (ED EPR) spectra of triplet state of fullerene C(70) generated by continuous light illumination were found to correspond below 30K to a non-equilibrium electron spin polarization. Above 30K spectra are characteristic of Boltzmann equilibrium. Spectra were simulated fairly well with zero-field splitting parameters D=153 MHz and E and distributed within the range of 6-42 MHz. The origin of E distribution is attributed to the Jahn-Teller effect, which in glassy matrix is expected to depend on the local surrounding of a fullerene molecule (a so-called E-strain). In the center of ED EPR spectra a narrow hole was observed. With increase of the microwave pulse turning angle this hole transforms into a single narrow absorptive line. Numerical simulations by density matrix formalism confirm that central hole originates from a simultaneous excitation of both allowed electron spin transitions of the triplet (T(0)↔T(+) and T(0)↔T(-)), because of their degeneracy at this spectral position. Also explanations are given why this hole has not been observed in the previously reported experiments on continuous wave EPR and on ED EPR under laser pulse excitation. PMID:21339084
Degeneracy and Effective Mass in the Valence Band of Two-Dimensional (100)-GaAs Quantum Well Systems
NASA Astrophysics Data System (ADS)
Tarquini, Vinicio; Knighton, Talbot; Wu, Zhe; Huang, Jian; Pfeifer, Loren; West, Ken
2014-03-01
Quantum Hall measurement of two-dimensional high-mobility (μ ~ 2 × 106 cm2/(V .s)) hole systems confined in a 20 nm wide (100)-GaAs quantum well have been performed for charge densities between 4 - 5 × 1010 cm-2 in a temperature range of 10-160 mK. The Fourier analysis of the Shubnikov-de Haas (SdH) oscillations of the magnetoresistance vs. the inverse of the magnetic field 1 /B⊥ reveals a single peak, indicating a degenerate heavy hole (HH) band. The corresponding hole density p =(e / h) . f agrees with the Hall measurement result within 3 % . The HH degeneracy is understood through the diminishing Rashba spin-orbit interaction due to the low charge density and the nearly symmetric confinement. SdH oscillations fitted for 0.1 T <=B⊥ <= 0 . 25 T to the Dingle parameters yield an effective mass (m*) between 0.39 me and 0.51 me that increases moderately with increasing magnetic field and charge density, in very good agreement with previous cyclotron resonance measurements. NSF DMR-1105183
Degeneracy and effective mass in the valence band of two-dimensional (100)-GaAs quantum well systems
NASA Astrophysics Data System (ADS)
Tarquini, Vinicio; Knighton, Talbot; Wu, Zhe; Huang, Jian; Pfeiffer, Loren; West, Ken
2014-03-01
Quantum Hall measurement of two-dimensional high-mobility [μ ˜2×106 cm2/(V.s)] hole systems confined in a 20 nm wide (100)-GaAs quantum well have been performed for charge densities between 4 and 5 × 1010 cm-2 in a temperature range of 10-160 mK. The Fourier analysis of the Shubnikov-de Haas (SdH) oscillations of the magnetoresistance vs. the inverse of the magnetic field 1/B reveals a single peak, indicating a degenerate heavy hole (HH) band. The hole density p =(e/h).f agrees with the Hall measurement result within 3%. The HH band degeneracy is understood through the diminishing spin-orbit interaction due to the low charge density and the nearly symmetric confinement. SdH oscillations fitted for 0.08 T ≤ B ≤ 0.24 T to the Dingle parameters yield an effective mass between 0.30 and 0.50 me in good agreement with previous cyclotron resonance results.
Levy, Mel E-mail: mlevy@tulane.edu; Anderson, James S. M.; Zadeh, Farnaz Heidar; Ayers, Paul W. E-mail: mlevy@tulane.edu
2014-05-14
Properties of exact density functionals provide useful constraints for the development of new approximate functionals. This paper focuses on convex sums of ground-level densities. It is observed that the electronic kinetic energy of a convex sum of degenerate ground-level densities is equal to the convex sum of the kinetic energies of the individual degenerate densities. (The same type of relationship holds also for the electron-electron repulsion energy.) This extends a known property of the Levy-Valone Ensemble Constrained-Search and the Lieb Legendre-Transform refomulations of the Hohenberg-Kohn functional to the individual components of the functional. Moreover, we observe that the kinetic and electron-repulsion results also apply to densities with fractional electron number (even if there are no degeneracies), and we close with an analogous point-wise property involving the external potential. Examples where different degenerate states have different kinetic energy and electron-nuclear attraction energy are given; consequently, individual components of the ground state electronic energy can change abruptly when the molecular geometry changes. These discontinuities are predicted to be ubiquitous at conical intersections, complicating the development of universally applicable density-functional approximations.
NASA Astrophysics Data System (ADS)
Gerischer, Heinz; McIntyre, Robert
1985-08-01
We have calculated the differential surface capacitance for two different semiconductors MoSe2(0001) and WSe2(0001), as a function of applied potential, for the condition of degeneracy. The calculated curves are compared with the experimentally measured capacitance for the systems, MoSe2(0001) in propylene carbonate containing 0.1 M LiClO4, for a range of crystal conductivities, and WSe2(0001) in acetonitrile containing 0.2 M (C3H7)4N BF4. As expected the experimental values are significantly lower than the calculated values, since the measured capacitance is the total capacitance for the system which is described by the surface capacitance of the semiconductor in series with the Helmholtz capacitance. Calculations based on this model, using the data for the Helmholtz capacitance for a mercury electrode in the same electrolyte, are shown to be in good agreement with the measured values. The results are discussed with particular reference to the screening distance for the semiconductor surface charge in the degenerate region.
NASA Astrophysics Data System (ADS)
Bétrémieux, Yan
2016-03-01
Detection of the signature of Rayleigh scattering in the transmission spectrum of an exoplanet is increasingly becoming the target of observational campaigns because the spectral slope of the Rayleigh continuum enables one to determine the scaleheight of its atmosphere in the absence of hazes. However, this is only true when one ignores the refractive effects of the exoplanet's atmosphere. I illustrate with a suite of simple isothermal clear Jovian H2-He atmosphere models with various abundances of water that refraction can decrease significantly the spectral slope of the Rayleigh continuum and that it becomes flat in the infrared. This mimics a surface, or an optically thick cloud deck, at much smaller pressures than one can probe in the non-refractive case. The relative impact of refraction on an exoplanet's transmission spectrum decreases with atmospheric temperatures and increases with stellar temperature. Refraction is quite important from a retrieval's perspective for Jovian-like planets even at the highest atmospheric temperatures (1200 K) considered in this paper, and for all stellar spectral types. Indeed, refraction breaks in large part the retrieval degeneracy between abundances of chemical species and the planet's radius because the size of spectral features increases significantly with abundances, in stark contrast with the non-refractive case which simply shifts them to a larger or smaller effective radius. Abundances inferred assuming that the atmosphere is cloud-free are lower limits. These results show how important it is to include refraction in retrieval algorithms to interpret transmission spectra of gas giants accurately.
Degeneracy and effective mass in the valence band of two-dimensional (100)-GaAs quantum well systems
Tarquini, Vinicio Knighton, Talbot; Wu, Zhe; Huang, Jian; Pfeiffer, Loren; West, Ken
2014-03-03
Quantum Hall measurement of two-dimensional high-mobility [μ∼2×10{sup 6} cm{sup 2}/(V·s)] hole systems confined in a 20 nm wide (100)-GaAs quantum well have been performed for charge densities between 4 and 5 × 10{sup 10} cm{sup −2} in a temperature range of 10–160 mK. The Fourier analysis of the Shubnikov-de Haas (SdH) oscillations of the magnetoresistance vs. the inverse of the magnetic field 1/B reveals a single peak, indicating a degenerate heavy hole (HH) band. The hole density p=(e/h)·f agrees with the Hall measurement result within 3%. The HH band degeneracy is understood through the diminishing spin-orbit interaction due to the low charge density and the nearly symmetric confinement. SdH oscillations fitted for 0.08 T ≤ B ≤ 0.24 T to the Dingle parameters yield an effective mass between 0.30 and 0.50 m{sub e} in good agreement with previous cyclotron resonance results.
NASA Astrophysics Data System (ADS)
Markoff, Sera; Nowak, Michael A.; Gallo, Elena; Hynes, Robert; Wilms, Jörn; Plotkin, Richard M.; Maitra, Dipankar; Silva, Catia V.; Drappeau, Samia
2015-10-01
Over the past decade, evidence has mounted that several aspects of black hole (BH) accretion physics proceed in a mass-invariant way. One of the best examples of this scaling is the empirical “fundamental plane of BH accretion” relation linking mass, radio, and X-ray luminosity over eight orders of magnitude in BH mass. The currently favored theoretical interpretation of this relation is that the physics governing power output in weakly accreting BHs depends more on relative accretion rate than on mass. In order to test this theory, we explore whether a mass-invariant approach can simultaneously explain the broadband spectral energy distributions from two BHs at opposite ends of the mass scale but that are at similar Eddington accretion fractions. We find that the same model, with the same value of several fitted physical parameters expressed in mass-scaling units to enforce self-similarity, can provide a good description of two data sets from V404 Cyg and M81*, a stellar and supermassive BH, respectively. Furthermore, only one of several potential emission scenarios for the X-ray band is successful, suggesting it is the dominant process driving the fundamental plane relation at this accretion rate. This approach thus holds promise for breaking current degeneracies in the interpretation of BH high-energy spectra and for constructing better prescriptions of BH accretion for use in various local and cosmological feedback applications.
NASA Astrophysics Data System (ADS)
Deppe, M.; Hartmann, S.; Macovei, M. E.; Oeschler, N.; Nicklas, M.; Geibel, C.
2008-09-01
We grew single crystals of Yb2Pt6Al15 and investigated the magnetic properties of this compound by means of susceptibility χ(T), specific heat C(T), resistivity ρ (T) and thermoelectric power S(T) measurements. While all properties follow in general the behavior typical for Kondo-lattice systems, χ(T) and C(T)/T present broad maxima in the T range 17 35 K, which matches nicely the prediction of the Coqblin Schrieffer model for J= 7/2. A large degeneracy of the local moment is also supported by a reduced Kadowaki Woods ratio. Thus, the analysis of all investigated properties evidences Yb2Pt6Al15 to be a paramagnetic Kondo-lattice system with the whole J= 7/2 multiplet involved in the formation of the Kondo state, a Kondo temperature of the order of 60 K, and a heavy Fermi-liquid ground state with a Sommerfeld coefficient γ 0 = 0.33 J (mol-Yb)-1 K-2 corresponding to a mass enhancement of the order of 30.
Resource capture by single leaves
Long, S.P.
1992-05-01
Leaves show a variety of strategies for maximizing CO{sub 2} and light capture. These are more meaningfully explained if they are considered in the context of maximizing capture relative to the utilization of water, nutrients and carbohydrates reserves. There is considerable variation between crops in their efficiency of CO{sub 2} and light capture at the leaf level. Understanding of these mechanisms indicate some ways in which efficiency of resource capture could be level cannot be meaningfully considered without simultaneous understanding of implications at the canopy level. 36 refs., 5 figs., 1 tab.
29 CFR 825.205 - Increments of FMLA leave for intermittent or reduced schedule leave.
Code of Federal Regulations, 2014 CFR
2014-07-01
... employee to take more leave than is necessary to address the circumstances that precipitated the need for... for any other type of leave. For example, if an employer accounts for the use of annual leave in... in shorter increments than used for other forms of leave. For example, an employer that accounts...
5 CFR 630.1104 - Donations from a leave bank to an emergency leave transfer program.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Donations from a leave bank to an emergency leave transfer program. 630.1104 Section 630.1104 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS ABSENCE AND LEAVE Emergency Leave Transfer Program § 630.1104...
5 CFR 630.1104 - Donations from a leave bank to an emergency leave transfer program.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Donations from a leave bank to an emergency leave transfer program. 630.1104 Section 630.1104 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS ABSENCE AND LEAVE Emergency Leave Transfer Program § 630.1104...
5 CFR 630.1104 - Donations from a leave bank to an emergency leave transfer program.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Donations from a leave bank to an emergency leave transfer program. 630.1104 Section 630.1104 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS ABSENCE AND LEAVE Emergency Leave Transfer Program § 630.1104...
5 CFR 630.1104 - Donations from a leave bank to an emergency leave transfer program.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Donations from a leave bank to an emergency leave transfer program. 630.1104 Section 630.1104 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS ABSENCE AND LEAVE Emergency Leave Transfer Program § 630.1104...
5 CFR 630.1104 - Donations from a leave bank to an emergency leave transfer program.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Donations from a leave bank to an emergency leave transfer program. 630.1104 Section 630.1104 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS ABSENCE AND LEAVE Emergency Leave Transfer Program § 630.1104...
NASA Astrophysics Data System (ADS)
Ghosh, Monojit; Ghoshal, Pomita; Goswami, Srubabati; Nath, Newton; Raut, Sushant K.
2016-01-01
The three major unknown neutrino oscillation parameters at the present juncture are the mass hierarchy, the octant of the mixing angle θ23 and the C P phase δC P . It is well known that the presence of hierarchy-δC P and octant degeneracies affects the unambiguous determination of these parameters. In this paper, we show that a comprehensive way to study the remaining parameter degeneracies is in the form of a generalized hierarchy-θ23-δC P degeneracy. This is best depicted as contours in the test (θ23-δC P ) plane for different representative true values of parameters. We show that the wrong-hierarchy and/or wrong-octant solutions can be further classified into eight different solutions depending on whether they occur with the wrong or right value of δC P. These eight solutions are different from the original eightfold degenerate solutions and can exist, in principle, even if θ13 is known. These multiple solutions, apart from affecting the determination of the true hierarchy and octant, also affect the accurate estimation of δC P. We identify which of these eight different degenerate solutions can occur in the test (θ23-δC P) parameter space, taking the long-baseline experiment NO ν A running in the neutrino mode as an example. The inclusion of the NO ν A antineutrino run removes the wrong-octant solutions appearing with both right and wrong hierarchy. Adding T2K data to this resolves the wrong hierarchy-right octant solutions to a large extent. The remaining wrong-hierarchy solutions can be removed by combining NO ν A +T 2 K with atmospheric neutrino data. We demonstrate this using ICAL@INO as the prototype atmospheric neutrino detector. We find that the degeneracies can be resolved at the 2 σ level by the combined data set, for the true parameter space considered in the study.
Hadi Alkarawi, H; Zotz, G
2014-07-01
Phytic acid or phytate, the free-acid form of myo-inositolhexakiphosphate, is abundant in many seeds and fruits, where it represents the major storage form of phosphorus. Although also known from other plant tissues, available reports on the occurrence of phytic acid, e.g. in leaves, have never been compiled, nor have they been critically reviewed. We found 45 published studies with information on phytic acid content in leaves. Phytic acid was almost always detected when studies specifically tried to detect it, and accounted for up to 98% of total P. However, we argue that such extreme values, which rival findings from storage organs, are dubious and probably result from measurement errors. Excluding these high values from further quantitative analysis, foliar phytic acid-P averaged 2.3 mg·g(-1) , and represented, on average, 7.6% of total P. Remarkably, the ratio of phytic acid-P to total P did not increase with total P, we even detected a negative correlation of the two variables within one species, Manihot esculenta. This enigmatic finding warrants further attention. PMID:24341824
Mercury uptake into poplar leaves.
Assad, Mohamad; Parelle, Julien; Cazaux, David; Gimbert, Frédéric; Chalot, Michel; Tatin-Froux, Fabienne
2016-03-01
Tailings dumps require mercury stabilization to prevent air pollution by evaporated mercury, which can be achieved through plant covers. Plants are considered a net sink for atmospheric Hg via incorporation into leaf tissues. However, most studies related to Hg uptake by plants have considered plants exposed to only atmospheric Hg, whereas in the case of tailings dumps, plants are potentially exposed to both soil and atmospheric Hg. The goal of this work is to evaluate the relative contributions of root and atmospheric pathways by growing poplar (Populus trichocarpa X Populus maximowiczii/var Skado) cuttings on either control or polluted substrates and under either natural or controlled exposure conditions. We showed that foliar Hg concentrations significantly increased with age, reaching 120 ng g(-1) dry mass when poplars were exposed to Hg-contaminated substrate under natural exposure. Remarkably, we did not observe significantly different Hg concentrations in poplar leaves grown on either the control or polluted substrates when cultivated together in growth chambers. Our set of data prompted us to conclude that Hg entry into poplar leaves is exclusively through an atmospheric pathway. Our results are discussed in line with existing literature. PMID:26694893
Kim, Ki Woo; Koo, Kyosang; Kim, Pan-Gi
2011-05-01
Effects of seawater spray on leaf structure were investigated in Quercus acutissima by electron microscopy and X-ray microanalysis. Two-year-old seedlings of Q. acutissima were sprayed with seawater and kept in a greenhouse maintained at 25°C. The most recognizable symptoms of seawater-sprayed seedlings included leaf necrosis, crystal deposition, stomatal clogging, and chloroplast degeneration. Field emission scanning electron microscopy revealed that the leaf surface was covered with additional layers of remnants of seawater spray. Composed of sodium and chloride, cube-shaped crystals (halite) were prevalently found on trichomes and epidermis, and formed aggregates. Meanwhile, wedge-shaped crystals were deposited on epidermis and consisted of calcium and sulfur. As a result of stomatal clogging by crystal deposition on the abaxial surface, it was conceivable that plant respiration became severely hampered. Transmission electron microscopy showed degenerated cytoplasm of seawater-sprayed leaves. It was common to observe severe plasmolysis and disrupted chloroplasts with a reduced number of thylakoids in grana. These results indicate that foliar applications of seawater were sufficient to induce necrosis of Q. acutissima seedlings as an abiotic disturbance factor. PMID:20931628
Bi, Huan -Yu; Wu, Xing -Gang; Ma, Yang; Ma, Hong -Hao; Brodsky, Stanley J.; Mojaza, Matin
2015-06-26
The Principle of Maximum Conformality (PMC) eliminates QCD renormalization scale-setting uncertainties using fundamental renormalization group methods. The resulting scale-fixed pQCD predictions are independent of the choice of renormalization scheme and show rapid convergence. The coefficients of the scale-fixed couplings are identical to the corresponding conformal series with zero β-function. Two all-orders methods for systematically implementing the PMC-scale setting procedure for existing high order calculations are discussed in this article. One implementation is based on the PMC-BLM correspondence (PMC-I); the other, more recent, method (PMC-II) uses the R_{δ}-scheme, a systematic generalization of the minimal subtraction renormalization scheme. Both approaches satisfy all of the principles of the renormalization group and lead to scale-fixed and scheme-independent predictions at each finite order. In this work, we show that PMC-I and PMC-II scale-setting methods are in practice equivalent to each other. We illustrate this equivalence for the four-loop calculations of the annihilation ratio R_{e+e–} and the Higgs partial width I'(H→bb¯). Both methods lead to the same resummed (‘conformal’) series up to all orders. The small scale differences between the two approaches are reduced as additional renormalization group {β_{i}}-terms in the pQCD expansion are taken into account. In addition, we show that special degeneracy relations, which underly the equivalence of the two PMC approaches and the resulting conformal features of the pQCD series, are in fact general properties of non-Abelian gauge theory.
NASA Astrophysics Data System (ADS)
Bi, Huan-Yu; Wu, Xing-Gang; Ma, Yang; Ma, Hong-Hao; Brodsky, Stanley J.; Mojaza, Matin
2015-09-01
The Principle of Maximum Conformality (PMC) eliminates QCD renormalization scale-setting uncertainties using fundamental renormalization group methods. The resulting scale-fixed pQCD predictions are independent of the choice of renormalization scheme and show rapid convergence. The coefficients of the scale-fixed couplings are identical to the corresponding conformal series with zero β-function. Two all-orders methods for systematically implementing the PMC-scale setting procedure for existing high order calculations are discussed in this article. One implementation is based on the PMC-BLM correspondence (PMC-I); the other, more recent, method (PMC-II) uses the Rδ-scheme, a systematic generalization of the minimal subtraction renormalization scheme. Both approaches satisfy all of the principles of the renormalization group and lead to scale-fixed and scheme-independent predictions at each finite order. In this work, we show that PMC-I and PMC-II scale-setting methods are in practice equivalent to each other. We illustrate this equivalence for the four-loop calculations of the annihilation ratio Re+e- and the Higgs partial width Γ (H → b b bar). Both methods lead to the same resummed ('conformal') series up to all orders. The small scale differences between the two approaches are reduced as additional renormalization group {βi }-terms in the pQCD expansion are taken into account. We also show that special degeneracy relations, which underly the equivalence of the two PMC approaches and the resulting conformal features of the pQCD series, are in fact general properties of non-Abelian gauge theory.
Autumn leaves seen through herbivore eyes
Döring, Thomas F; Archetti, Marco; Hardie, Jim
2008-01-01
Why leaves of some trees turn red in autumn has puzzled biologists for decades, as just before leaf fall the pigments causing red coloration are newly synthesized. One idea to explain this apparently untimely investment is that red colour signals the tree's quality to herbivorous insects, particularly aphids. However, it is unclear whether red leaves are indeed less attractive to aphids than green leaves. Because aphids lack a red photoreceptor, it was conjectured that red leaves could even be indiscernable from green ones for these insects. Here we show, however, that the colour of autumnal tree leaves that appear red to humans are on average much less attractive to aphids than green leaves, whereas yellow leaves are much more attractive. We conclude that, while active avoidance of red leaves by aphids is unlikely, red coloration in autumn could still be a signal of the tree's quality, or alternatively serve to mask the over-attractive yellow that is unveiled when the green chlorophyll is recovered from senescing leaves. Our study shows that in sensory ecology, receiver physiology alone is not sufficient to reveal the whole picture. Instead, the combined analysis of behaviour and a large set of natural stimuli unexpectedly shows that animals lacking a red photoreceptor may be able to differentiate between red and green leaves. PMID:18782744
Phenolics of Moringa oleifera leaves.
Manguro, Lawrence Onyango Arot; Lemmen, Peter
2007-01-01
Five flavonol glycosides characterised as kaempferide 3-O-(2'',3''-diacetylglucoside), kaempferide 3-O-(2''-O-galloylrhamnoside), kaempferide 3-O-(2''-O-galloylrutinoside)-7-O-alpha-rhamnoside, kaempferol 3-O-[beta-glucosyl-(1 --> 2)]-[alpha-rhamnosyl-(1 --> 6)]-beta-glucoside-7-O-alpha-rhamnoside and kaempferol 3-O-[alpha-rhamnosyl-(1 --> 2)]-[alpha-rhamnosyl-(1 --> 4)]-beta-glucoside-7-O-alpha-rhamnoside together with benzoic acid 4-O-beta-glucoside, benzoic acid 4-O-alpha-rhamnosyl-(1 --> 2)-beta-glucoside and benzaldehyde 4-O-beta-glucoside have been isolated from methanolic extract of Moringa oleifera leaves. Also obtained from the same extract were known compounds, kaempferol 3-O-alpha-rhamnoside, kaempferol, syringic acid, gallic acid, rutin and quercetin 3-O-beta-glucoside. Their structures were determined using spectroscopic methods as well as comparison with data from known compounds. PMID:17365690
The cardioprotective power of leaves
Boncler, Magdalena; Watala, Cezary
2015-01-01
Lack of physical activity, smoking and/or inappropriate diet can contribute to the increase of oxidative stress, in turn affecting the pathophysiology of cardiovascular diseases. Strong anti-oxidant properties of plant polyphenolic compounds might underlie their cardioprotective activity. This paper reviews recent findings on the anti-oxidant activity of plant leaf extracts and emphasizes their effects on blood platelets, leukocytes and endothelial cells – the targets orchestrating the development and progression of cardiovascular diseases. We also review the evidence linking supplementation with plant leaf extracts and the risk factors defining the metabolic syndrome. The data point to the importance of leaves as an alternative source of polyphenolic compounds in the human diet and their role in the prevention of cardiovascular diseases. PMID:26322095
Convergence, Degeneracy, and Control
ERIC Educational Resources Information Center
Green, David W.; Crinion, Jenny; Price, Cathy J.
2006-01-01
Understanding the neural representation and control of language in normal bilingual speakers provides insights into the factors that constrain the acquisition of another language, insights into the nature of language expertise, and an understanding of the brain as an adaptive system. We illustrate both functional and structural brain changes…
Convergence, degeneracy and control.
Green, David W; Crinion, J; Price, Cathy J
2006-07-01
Understanding the neural representation and control of language in normal bilingual speakers provides insights into the factors that constrain the acquisition of another language, insights into the nature of language expertise and an understanding of the brain as an adaptive system. We illustrate both functional and structural brain changes associated with acquiring other languages and discuss the value of neuroimaging data in identifying individual differences and different phenotypes. Understanding normal variety is vital too if we are to understand the consequences of brain-damage in bilingual and polyglot speakers. PMID:18273402
Convergence, degeneracy and control
Green, David W.; Crinion, J.; Price, Cathy J.
2007-01-01
Understanding the neural representation and control of language in normal bilingual speakers provides insights into the factors that constrain the acquisition of another language, insights into the nature of language expertise and an understanding of the brain as an adaptive system. We illustrate both functional and structural brain changes associated with acquiring other languages and discuss the value of neuroimaging data in identifying individual differences and different phenotypes. Understanding normal variety is vital too if we are to understand the consequences of brain-damage in bilingual and polyglot speakers. PMID:18273402
Paid Sick Leave and Job Stability
Hill, Heather D.
2013-01-01
A compelling, but unsubstantiated, argument for paid sick leave legislation is that workers with leave are better able to address own and family member health needs without risking a voluntary or involuntary job separation. This study tests that claim using the Medical Expenditure Panel Survey and regression models controlling for a large set of worker and job characteristics, as well as with propensity score techniques. Results suggest that paid sick leave decreases the probability of job separation by at least 2.5 percentage points, or 25%. The association is strongest for workers without paid vacation leave and for mothers. PMID:24235780
Paid Sick Leave and Job Stability.
Hill, Heather D
2013-05-01
A compelling, but unsubstantiated, argument for paid sick leave legislation is that workers with leave are better able to address own and family member health needs without risking a voluntary or involuntary job separation. This study tests that claim using the Medical Expenditure Panel Survey and regression models controlling for a large set of worker and job characteristics, as well as with propensity score techniques. Results suggest that paid sick leave decreases the probability of job separation by at least 2.5 percentage points, or 25%. The association is strongest for workers without paid vacation leave and for mothers. PMID:24235780
Developments in Educational Leave of Absence.
ERIC Educational Resources Information Center
Organisation for Economic Cooperation and Development, Paris (France). Centre for Educational Research and Innovation.
The document evaluates present international developments in the area of leave of absence during working hours for educational purposes. Part 1, Educational Leave of Absence: A Comparative Analysis, contains five chapters: (1) Towards a New Right to Education, discussing recurrent education, the world of work, the International Labor Organization,…
Developing an Alternative Sabbatical Leave Policy.
ERIC Educational Resources Information Center
Holleman, John J.
A study was conducted at Vista College to compare the sabbatical leave policy of the Peralta Community College District with those of other districts and to develop alternative policies that would permit a greater number of faculty to obtain sabbatical leaves. Policy statements were received from nine of the twelve districts surveyed, and…
Resilience and Young People Leaving Care
ERIC Educational Resources Information Center
Stein, Mike
2008-01-01
How do we promote the resilience of young people leaving care? This article explores this question by bringing together research findings on the resilience of young people from disadvantaged family backgrounds with research studies on young people leaving care. These findings are applied to young people during their journey to adulthood: their…
A Feminist Perspective on Parental Leave Policies
ERIC Educational Resources Information Center
Sallee, Margaret W.
2008-01-01
This article focuses on the ways that three feminist theories--liberal feminism, cultural feminism, and feminist poststructuralism--might be used to craft parental leave policies. After examining each theory in detail, the article concludes by offering one example of an ideal parental leave policy that combines the best features of each theory to…
Ensiling Characteristics of Alfalfa Leaves and Stems
Technology Transfer Automated Retrieval System (TEKTRAN)
The separate harvesting of alfalfa leaves and stems would provide farmers more flexibility in the harvesting and utilization of alfalfa, but a key issue is storage. In three trials, unwilted alfalfa leaves were ensiled alone or with cell wall degrading enzymes, formic acid or lactic acid bacterial i...
29 CFR 825.202 - Intermittent leave or reduced leave schedule.
Code of Federal Regulations, 2010 CFR
2010-07-01
... LABOR OTHER LAWS THE FAMILY AND MEDICAL LEAVE ACT OF 1993 Employee Leave Entitlements Under the Family... also be taken to provide care or psychological comfort to a covered family member with a serious health... reduced schedule leave may be taken for absences where the employee or family member is incapacitated...
Changes in spectral properties of detached leaves
NASA Technical Reports Server (NTRS)
Daughtry, C. S. T.; Biehl, L. L.
1984-01-01
If leaf senescence can be delayed for several days without significant changes in spectral properties, then samples of leaves at remote test sites could be prepared and shipped to laboratories to measure spectral properties. The changes in spectral properties of detached leaves were determined. Leaves from red birch and red pine were immersed in water or 0.001 M benzylaminopurine (BAP) and stored in plastic bags in the dark at either 5 or 25 C. Total directional-hemispherical reflectance and transmittance of the adaxial surface of birch leaves were measured over the 400 to 1100 nm wavelength region with a spectroradiometer and integrating sphere. Pine needles were taped together and reflectance of the mat of needles was measured. Spectral properties changed less than 5% of initial values during the first week when leaves were stored at 5 C. Storage at 25 C promoted rapid senescence and large changes in spectral properties. BAP delayed, but did not stop, senescence at 25 C.
Yang, Shan; Al-Hashimi, Hashim M
2015-07-30
A growing number of studies employ time-averaged experimental data to determine dynamic ensembles of biomolecules. While it is well-known that different ensembles can satisfy experimental data to within error, the extent and nature of these degeneracies, and their impact on the accuracy of the ensemble determination remains poorly understood. Here, we use simulations and a recently introduced metric for assessing ensemble similarity to explore degeneracies in determining ensembles using NMR residual dipolar couplings (RDCs) with specific application to A-form helices in RNA. Various target ensembles were constructed representing different domain-domain orientational distributions that are confined to a topologically restricted (<10%) conformational space. Five independent sets of ensemble averaged RDCs were then computed for each target ensemble and a "sample and select" scheme used to identify degenerate ensembles that satisfy RDCs to within experimental uncertainty. We find that ensembles with different ensemble sizes and that can differ significantly from the target ensemble (by as much as ∑Ω ∼ 0.4 where ∑Ω varies between 0 and 1 for maximum and minimum ensemble similarity, respectively) can satisfy the ensemble averaged RDCs. These deviations increase with the number of unique conformers and breadth of the target distribution, and result in significant uncertainty in determining conformational entropy (as large as 5 kcal/mol at T = 298 K). Nevertheless, the RDC-degenerate ensembles are biased toward populated regions of the target ensemble, and capture other essential features of the distribution, including the shape. Our results identify ensemble size as a major source of uncertainty in determining ensembles and suggest that NMR interactions such as RDCs and spin relaxation, on their own, do not carry the necessary information needed to determine conformational entropy at a useful level of precision. The framework introduced here provides a general
Asfin, Ruslan E; Melikova, Sona M; Domanskaya, Alexandra V; Rodziewicz, Paweł; Rutkowski, Konstantin S
2016-05-26
The FTIR spectra of fluoroform trapped in argon and nitrogen matrixes are studied at T ∼ 10-30 K. The bands of E symmetry show the splitting effect in a nitrogen matrix, which is absent in an argon matrix. The effect is the most prominent in the case of the ν4 CH bending vibration. It decreases slightly with increasing temperature. Both static and Car-Parrinello molecular dynamic simulations suggest that the degeneracy lifting is due to C3v symmetry lowering caused by interactions between fluoroform and all neighbor N2 matrix molecules. PMID:27149085
Influence of pesticides on yeasts colonizing leaves.
Vadkertiová, Renata; Sláviková, Elena
2011-01-01
The effect of nine different pesticides on the growth of yeasts isolated from the leaves of fruit and forest trees was investigated. Four insecticides (with the active ingredients: thiacloprid, deltamethrin, lambdacyhalothrin, and thiamethoxam) and five fungicides (with the effective substances: bitertanol, kresoxim-methyl, mancozeb, trifloxystrobin, and cupric oxychloride) were tested. The concentrations of chemicals were those recommended by the manufacturers for the spraying of trees. The yeast strains isolated from the leaves of fruit trees were not sensitive to any of the insecticides. The majority of yeast strains isolated from the leaves of forest trees were either not sensitive or only to a small extent. While Rhodotorula mucilaginosa and Pichia anomala were not affected by any insecticide, the strains of Cryptococcus laurentii and Rhodotorula glutinis showed the highest sensitivity. The effects of fungicides on the growth of isolated yeasts were more substantial. The fungicide Dithane DG (mancozeb) completely inhibited the growth of all yeasts. All strains isolated from fruit tree leaves were more resistant to the tested fungicides than those isolated from the leaves of forest trees. The most resistant strains from the leaves of fruit trees belonged to the species Metschnikowia pulcherrima, Pichia anomala, and Saccharomyces cerevisiae, whereas Cryptococcus albidus and C. laurentii, originating from the leaves of forest trees, showed the highest sensitivity to fungicides. PMID:22351984
Paid Sick Leave and Nonfatal Occupational Injuries
Pana-Cryan, Regina; Rosa, Roger
2012-01-01
Objectives. We examined the association between US workers’ access to paid sick leave and the incidence of nonfatal occupational injuries from the employer’s perspective. We also examined this association in different industries and occupations. Methods. We developed a theoretical framework to examine the business value of offering paid sick leave. Data from the National Health Interview Survey were used to test the hypothesis that offering paid sick leave is associated with a reduced incidence of occupational injuries. We used data on approximately 38 000 working adults to estimate a multivariate model. Results. With all other variables held constant, workers with access to paid sick leave were 28% (95% confidence interval = 0.52, 0.99) less likely than workers without access to paid sick leave to be injured. The association between the availability of paid sick leave and the incidence of occupational injuries varied across sectors and occupations, with the greatest differences occurring in high-risk sectors and occupations. Conclusions. Our findings suggest that, similar to other investments in worker safety and health, introducing or expanding paid sick leave programs might help businesses reduce the incidence of nonfatal occupational injuries, particularly in high-risk sectors and occupations. PMID:22720767
5 CFR 630.911 - Restoration of transferred annual leave.
Code of Federal Regulations, 2013 CFR
2013-01-01
...' Compensation Programs under 20 CFR 10.202 and 10.310, and the annual leave was leave transferred under § 630... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Restoration of transferred annual leave... REGULATIONS ABSENCE AND LEAVE Voluntary Leave Transfer Program § 630.911 Restoration of transferred...
5 CFR 630.911 - Restoration of transferred annual leave.
Code of Federal Regulations, 2011 CFR
2011-01-01
...' Compensation Programs under 20 CFR 10.202 and 10.310, and the annual leave was leave transferred under § 630... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Restoration of transferred annual leave... REGULATIONS ABSENCE AND LEAVE Voluntary Leave Transfer Program § 630.911 Restoration of transferred...
5 CFR 630.911 - Restoration of transferred annual leave.
Code of Federal Regulations, 2014 CFR
2014-01-01
...' Compensation Programs under 20 CFR 10.202 and 10.310, and the annual leave was leave transferred under § 630... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Restoration of transferred annual leave... REGULATIONS ABSENCE AND LEAVE Voluntary Leave Transfer Program § 630.911 Restoration of transferred...
5 CFR 630.911 - Restoration of transferred annual leave.
Code of Federal Regulations, 2010 CFR
2010-01-01
...' Compensation Programs under 20 CFR 10.202 and 10.310, and the annual leave was leave transferred under § 630... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Restoration of transferred annual leave... REGULATIONS ABSENCE AND LEAVE Voluntary Leave Transfer Program § 630.911 Restoration of transferred...
5 CFR 630.606 - Grant of home leave.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Grant of home leave. 630.606 Section 630... LEAVE Home Leave § 630.606 Grant of home leave. (a) Entitlement. Except as otherwise authorized by statute, an employee is entitled to home leave only when he has completed a basic service period of...
5 CFR 630.605 - Computation of home leave.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Computation of home leave. 630.605... AND LEAVE Home Leave § 630.605 Computation of home leave. (a) For each month of service abroad, an employee earns home leave under the rates fixed by § 630.604(a) in the amounts set forth in the...
5 CFR 630.606 - Grant of home leave.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Grant of home leave. 630.606 Section 630... LEAVE Home Leave § 630.606 Grant of home leave. (a) Entitlement. Except as otherwise authorized by statute, an employee is entitled to home leave only when he has completed a basic service period of...