FIMP dark matter freeze-in gauge mediation and hidden sector
NASA Astrophysics Data System (ADS)
Tsao, Kuo-Hsing
2018-07-01
We explore the dark matter freeze-in mechanism within the gauge mediation framework, which involves a hidden feebly interacting massive particle (FIMP) coupling feebly with the messenger fields while the messengers are still in the thermal bath. The FIMP is the fermionic component of the pseudo-moduli in a generic metastable supersymmetry (SUSY) breaking model and resides in the hidden sector. The relic abundance and the mass of the FIMP are determined by the SUSY breaking scale and the feeble coupling. The gravitino, which is the canonical dark matter candidate in the gauge mediation framework, contributes to the dark matter relic abundance along with the freeze-in of the FIMP. The hidden sector thus becomes two-component with both the FIMP and gravitino lodging in the SUSY breaking hidden sector. We point out that the ratio between the FIMP and the gravitino is determined by how SUSY breaking is communicated to the messengers. In particular when the FIMP dominates the hidden sector, the gravitino becomes the minor contributor in the hidden sector. Meanwhile, the neutralino is assumed to be both the weakly interacting massive particle dark matter candidate in the freeze-out mechanism and the lightest observable SUSY particle. We further find out the neutralino has the sub-leading contribution to the current dark matter relic density in the parameter space of our freeze-in gauge mediation model. Our result links the SUSY breaking scale in the gauge mediation framework with the FIMP freeze-in production rate leading to a natural and predicting scenario for the studies of the dark matter in the hidden sector.
Hidden SU ( N ) glueball dark matter
Soni, Amarjit; Zhang, Yue
2016-06-21
Here we investigate the possibility that the dark matter candidate is from a pure non-abelian gauge theory of the hidden sector, motivated in large part by its elegance and simplicity. The dark matter is the lightest bound state made of the confined gauge fields, the hidden glueball. We point out this simple setup is capable of providing rich and novel phenomena in the dark sector, especially in the parameter space of large N. They include self-interacting and warm dark matter scenarios, Bose-Einstein condensation leading to massive dark stars possibly millions of times heavier than our sun giving rise to gravitationalmore » lensing effects, and indirect detections through higher dimensional operators as well as interesting collider signatures.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Farina, Marco; Pappadopulo, Duccio; Ruderman, Joshua T.
A hidden sector with a mass gap undergoes an epoch of cannibalism if number changing interactions are active when the temperature drops below the mass of the lightest hidden particle. During cannibalism, the hidden sector temperature decreases only logarithmically with the scale factor. We consider the possibility that dark matter resides in a hidden sector that underwent cannibalism, and has relic density set by the freeze-out of two-to-two annihilations. We identify three novel phases, depending on the behavior of the hidden sector when dark matter freezes out. During the cannibal phase, dark matter annihilations decouple while the hidden sector ismore » cannibalizing. During the chemical phase, only two-to-two interactions are active and the total number of hidden particles is conserved. During the one way phase, the dark matter annihilation products decay out of equilibrium, suppressing the production of dark matter from inverse annihilations. We map out the distinct phenomenology of each phase, which includes a boosted dark matter annihilation rate, new relativistic degrees of freedom, warm dark matter, and observable distortions to the spectrum of the cosmic microwave background.« less
Phases of cannibal dark matter
NASA Astrophysics Data System (ADS)
Farina, Marco; Pappadopulo, Duccio; Ruderman, Joshua T.; Trevisan, Gabriele
2016-12-01
A hidden sector with a mass gap undergoes an epoch of cannibalism if number changing interactions are active when the temperature drops below the mass of the lightest hidden particle. During cannibalism, the hidden sector temperature decreases only logarithmically with the scale factor. We consider the possibility that dark matter resides in a hidden sector that underwent cannibalism, and has relic density set by the freeze-out of two-to-two annihilations. We identify three novel phases, depending on the behavior of the hidden sector when dark matter freezes out. During the cannibal phase, dark matter annihilations decouple while the hidden sector is cannibalizing. During the chemical phase, only two-to-two interactions are active and the total number of hidden particles is conserved. During the one way phase, the dark matter annihilation products decay out of equilibrium, suppressing the production of dark matter from inverse annihilations. We map out the distinct phenomenology of each phase, which includes a boosted dark matter annihilation rate, new relativistic degrees of freedom, warm dark matter, and observable distortions to the spectrum of the cosmic microwave background.
Phases of cannibal dark matter
Farina, Marco; Pappadopulo, Duccio; Ruderman, Joshua T.; ...
2016-12-13
A hidden sector with a mass gap undergoes an epoch of cannibalism if number changing interactions are active when the temperature drops below the mass of the lightest hidden particle. During cannibalism, the hidden sector temperature decreases only logarithmically with the scale factor. We consider the possibility that dark matter resides in a hidden sector that underwent cannibalism, and has relic density set by the freeze-out of two-to-two annihilations. We identify three novel phases, depending on the behavior of the hidden sector when dark matter freezes out. During the cannibal phase, dark matter annihilations decouple while the hidden sector ismore » cannibalizing. During the chemical phase, only two-to-two interactions are active and the total number of hidden particles is conserved. During the one way phase, the dark matter annihilation products decay out of equilibrium, suppressing the production of dark matter from inverse annihilations. We map out the distinct phenomenology of each phase, which includes a boosted dark matter annihilation rate, new relativistic degrees of freedom, warm dark matter, and observable distortions to the spectrum of the cosmic microwave background.« less
On the LHC sensitivity for non-thermalised hidden sectors
NASA Astrophysics Data System (ADS)
Kahlhoefer, Felix
2018-04-01
We show under rather general assumptions that hidden sectors that never reach thermal equilibrium in the early Universe are also inaccessible for the LHC. In other words, any particle that can be produced at the LHC must either have been in thermal equilibrium with the Standard Model at some point or must be produced via the decays of another hidden sector particle that has been in thermal equilibrium. To reach this conclusion, we parametrise the cross section connecting the Standard Model to the hidden sector in a very general way and use methods from linear programming to calculate the largest possible number of LHC events compatible with the requirement of non-thermalisation. We find that even the HL-LHC cannot possibly produce more than a few events with energy above 10 GeV involving states from a non-thermalised hidden sector.
LHC searches for dark sector showers
NASA Astrophysics Data System (ADS)
Cohen, Timothy; Lisanti, Mariangela; Lou, Hou Keong; Mishra-Sharma, Siddharth
2017-11-01
This paper proposes a new search program for dark sector parton showers at the Large Hadron Collider (LHC). These signatures arise in theories characterized by strong dynamics in a hidden sector, such as Hidden Valley models. A dark parton shower can be composed of both invisible dark matter particles as well as dark sector states that decay to Standard Model particles via a portal. The focus here is on the specific case of `semi-visible jets,' jet-like collider objects where the visible states in the shower are Standard Model hadrons. We present a Simplified Model-like parametrization for the LHC observables and propose targeted search strategies for regions of parameter space that are not covered by existing analyses. Following the `mono- X' literature, the portal is modeled using either an effective field theoretic contact operator approach or with one of two ultraviolet completions; sensitivity projections are provided for all three cases. We additionally highlight that the LHC has a unique advantage over direct detection experiments in the search for this class of dark matter theories.
Gauge mediation scenario with hidden sector renormalization in MSSM
NASA Astrophysics Data System (ADS)
Arai, Masato; Kawai, Shinsuke; Okada, Nobuchika
2010-02-01
We study the hidden sector effects on the mass renormalization of a simplest gauge-mediated supersymmetry breaking scenario. We point out that possible hidden sector contributions render the soft scalar masses smaller, resulting in drastically different sparticle mass spectrum at low energy. In particular, in the 5+5¯ minimal gauge-mediated supersymmetry breaking with high messenger scale (that is favored by the gravitino cold dark matter scenario), we show that a stau can be the next lightest superparticle for moderate values of hidden sector self-coupling. This provides a very simple theoretical model of long-lived charged next lightest superparticles, which imply distinctive signals in ongoing and upcoming collider experiments.
Hidden sector dark matter and the Galactic Center gamma-ray excess: a closer look
Escudero, Miguel; Witte, Samuel J.; Hooper, Dan
2017-11-24
Stringent constraints from direct detection experiments and the Large Hadron Collider motivate us to consider models in which the dark matter does not directly couple to the Standard Model, but that instead annihilates into hidden sector particles which ultimately decay through small couplings to the Standard Model. We calculate the gamma-ray emission generated within the context of several such hidden sector models, including those in which the hidden sector couples to the Standard Model through the vector portal (kinetic mixing with Standard Model hypercharge), through the Higgs portal (mixing with the Standard Model Higgs boson), or both. In each case,more » we identify broad regions of parameter space in which the observed spectrum and intensity of the Galactic Center gamma-ray excess can easily be accommodated, while providing an acceptable thermal relic abundance and remaining consistent with all current constraints. Here, we also point out that cosmic-ray antiproton measurements could potentially discriminate some hidden sector models from more conventional dark matter scenarios.« less
Hidden Sector Dark Matter and the Galactic Center Gamma-Ray Excess: A Closer Look
DOE Office of Scientific and Technical Information (OSTI.GOV)
Escudero, Miguel; Witte, Samuel J.; Hooper, Dan
2017-09-20
Stringent constraints from direct detection experiments and the Large Hadron Collider motivate us to consider models in which the dark matter does not directly couple to the Standard Model, but that instead annihilates into hidden sector particles which ultimately decay through small couplings to the Standard Model. We calculate the gamma-ray emission generated within the context of several such hidden sector models, including those in which the hidden sector couples to the Standard Model through the vector portal (kinetic mixing with Standard Model hypercharge), through the Higgs portal (mixing with the Standard Model Higgs boson), or both. In each case,more » we identify broad regions of parameter space in which the observed spectrum and intensity of the Galactic Center gamma-ray excess can easily be accommodated, while providing an acceptable thermal relic abundance and remaining consistent with all current constraints. We also point out that cosmic-ray antiproton measurements could potentially discriminate some hidden sector models from more conventional dark matter scenarios.« less
Hidden sector dark matter and the Galactic Center gamma-ray excess: a closer look
NASA Astrophysics Data System (ADS)
Escudero, Miguel; Witte, Samuel J.; Hooper, Dan
2017-11-01
Stringent constraints from direct detection experiments and the Large Hadron Collider motivate us to consider models in which the dark matter does not directly couple to the Standard Model, but that instead annihilates into hidden sector particles which ultimately decay through small couplings to the Standard Model. We calculate the gamma-ray emission generated within the context of several such hidden sector models, including those in which the hidden sector couples to the Standard Model through the vector portal (kinetic mixing with Standard Model hypercharge), through the Higgs portal (mixing with the Standard Model Higgs boson), or both. In each case, we identify broad regions of parameter space in which the observed spectrum and intensity of the Galactic Center gamma-ray excess can easily be accommodated, while providing an acceptable thermal relic abundance and remaining consistent with all current constraints. We also point out that cosmic-ray antiproton measurements could potentially discriminate some hidden sector models from more conventional dark matter scenarios.
Hidden sector dark matter and the Galactic Center gamma-ray excess: a closer look
DOE Office of Scientific and Technical Information (OSTI.GOV)
Escudero, Miguel; Witte, Samuel J.; Hooper, Dan
Stringent constraints from direct detection experiments and the Large Hadron Collider motivate us to consider models in which the dark matter does not directly couple to the Standard Model, but that instead annihilates into hidden sector particles which ultimately decay through small couplings to the Standard Model. We calculate the gamma-ray emission generated within the context of several such hidden sector models, including those in which the hidden sector couples to the Standard Model through the vector portal (kinetic mixing with Standard Model hypercharge), through the Higgs portal (mixing with the Standard Model Higgs boson), or both. In each case,more » we identify broad regions of parameter space in which the observed spectrum and intensity of the Galactic Center gamma-ray excess can easily be accommodated, while providing an acceptable thermal relic abundance and remaining consistent with all current constraints. Here, we also point out that cosmic-ray antiproton measurements could potentially discriminate some hidden sector models from more conventional dark matter scenarios.« less
Graviweak Unification, Invisible Universe and Dark Energy
NASA Astrophysics Data System (ADS)
Das, C. R.; Laperashvili, L. V.; Tureanu, A.
2013-07-01
We consider a graviweak unification model with the assumption of the existence of a hidden (invisible) sector of our Universe, parallel to the visible world. This Hidden World (HW) is assumed to be a Mirror World (MW) with broken mirror parity. We start with a diffeomorphism invariant theory of a gauge field valued in a Lie algebra g, which is broken spontaneously to the direct sum of the space-time Lorentz algebra and the Yang-Mills algebra: ˜ {g} = {{su}}(2) (grav)L ⊕ {{su}}(2)L — in the ordinary world, and ˜ {g}' = {{su}}(2){' (grav)}R ⊕ {{su}}(2)'R — in the hidden world. Using an extension of the Plebanski action for general relativity, we recover the actions for gravity, SU(2) Yang-Mills and Higgs fields in both (visible and invisible) sectors of the Universe, and also the total action. After symmetry breaking, all physical constants, including the Newton's constants, cosmological constants, Yang-Mills couplings, and other parameters, are determined by a single parameter g present in the initial action, and by the Higgs VEVs. The dark energy problem of this model predicts a too large supersymmetric breaking scale (MSUSY 1010GeV), which is not within the reach of the LHC experiments.
Dissipative hidden sector dark matter
NASA Astrophysics Data System (ADS)
Foot, R.; Vagnozzi, S.
2015-01-01
A simple way of explaining dark matter without modifying known Standard Model physics is to require the existence of a hidden (dark) sector, which interacts with the visible one predominantly via gravity. We consider a hidden sector containing two stable particles charged under an unbroken U (1 )' gauge symmetry, hence featuring dissipative interactions. The massless gauge field associated with this symmetry, the dark photon, can interact via kinetic mixing with the ordinary photon. In fact, such an interaction of strength ε ˜10-9 appears to be necessary in order to explain galactic structure. We calculate the effect of this new physics on big bang nucleosynthesis and its contribution to the relativistic energy density at hydrogen recombination. We then examine the process of dark recombination, during which neutral dark states are formed, which is important for large-scale structure formation. Galactic structure is considered next, focusing on spiral and irregular galaxies. For these galaxies we modeled the dark matter halo (at the current epoch) as a dissipative plasma of dark matter particles, where the energy lost due to dissipation is compensated by the energy produced from ordinary supernovae (the core-collapse energy is transferred to the hidden sector via kinetic mixing induced processes in the supernova core). We find that such a dynamical halo model can reproduce several observed features of disk galaxies, including the cored density profile and the Tully-Fisher relation. We also discuss how elliptical and dwarf spheroidal galaxies could fit into this picture. Finally, these analyses are combined to set bounds on the parameter space of our model, which can serve as a guideline for future experimental searches.
Rare Z boson decays to a hidden sector
Blinov, Nikita; Izaguirre, Eder; Shuve, Brian
2018-01-18
We demonstrate that rare decays of the Standard Model Z boson can be used to discover and characterize the nature of new hidden-sector particles. We propose new searches for these particles in soft, high-multiplicity leptonic final states at the Large Hadron Collider. The proposed searches are sensitive to low-mass particles produced in Z decays, and we argue that these striking signatures can shed light on the hidden-sector couplings and mechanism for mass generation.
Rare Z boson decays to a hidden sector
Blinov, Nikita; Izaguirre, Eder; Shuve, Brian
2018-01-01
We demonstrate that rare decays of the Standard Model Z boson can be used to discover and characterize the nature of new hidden-sector particles. We propose new searches for these particles in soft, high-multiplicity leptonic final states at the Large Hadron Collider. The proposed searches are sensitive to low-mass particles produced in Z decays, and we argue that these striking signatures can shed light on the hidden-sector couplings and mechanism for mass generation.
Rare Z boson decays to a hidden sector
DOE Office of Scientific and Technical Information (OSTI.GOV)
Blinov, Nikita; Izaguirre, Eder; Shuve, Brian
We demonstrate that rare decays of the Standard Model Z boson can be used to discover and characterize the nature of new hidden-sector particles. We propose new searches for these particles in soft, high-multiplicity leptonic final states at the Large Hadron Collider. The proposed searches are sensitive to low-mass particles produced in Z decays, and we argue that these striking signatures can shed light on the hidden-sector couplings and mechanism for mass generation.
Hidden-sector Spectroscopy with Gravitational Waves from Binary Neutron Stars
NASA Astrophysics Data System (ADS)
Croon, Djuna; Nelson, Ann E.; Sun, Chen; Walker, Devin G. E.; Xianyu, Zhong-Zhi
2018-05-01
We show that neutron star (NS) binaries can be ideal laboratories to probe hidden sectors with a long-range force. In particular, it is possible for gravitational wave (GW) detectors such as LIGO and Virgo to resolve the correction of waveforms from ultralight dark gauge bosons coupled to NSs. We observe that the interaction of the hidden sector affects both the GW frequency and amplitude in a way that cannot be fitted by pure gravity.
Singlet scalar top partners from accidental supersymmetry
NASA Astrophysics Data System (ADS)
Cheng, Hsin-Chia; Li, Lingfeng; Salvioni, Ennio; Verhaaren, Christopher B.
2018-05-01
We present a model wherein the Higgs mass is protected from the quadratic one-loop top quark corrections by scalar particles that are complete singlets under the Standard Model (SM) gauge group. While bearing some similarity to Folded Supersymmetry, the construction is purely four dimensional and enjoys more parametric freedom, allowing electroweak symmetry breaking to occur easily. The cancelation of the top loop quadratic divergence is ensured by a Z 3 symmetry that relates the SM top sector and two hidden top sectors, each charged under its own hidden color group. In addition to the singlet scalars, the hidden sectors contain electroweak-charged supermultiplets below the TeV scale, which provide the main access to this model at colliders. The phenomenology presents both differences and similarities with respect to other realizations of neutral naturalness. Generally, the glueballs of hidden color have longer decay lengths. The production of hidden sector particles results in quirk or squirk bound states, which later annihilate. We survey the possible signatures and corresponding experimental constraints.
Dark matter freeze-out in a nonrelativistic sector
NASA Astrophysics Data System (ADS)
Pappadopulo, Duccio; Ruderman, Joshua T.; Trevisan, Gabriele
2016-08-01
A thermally decoupled hidden sector of particles, with a mass gap, generically enters a phase of cannibalism in the early Universe. The Standard Model sector becomes exponentially colder than the hidden sector. We propose the cannibal dark matter framework, where dark matter resides in a cannibalizing sector with a relic density set by 2-to-2 annihilations. Observable signals of cannibal dark matter include a boosted rate for indirect detection, new relativistic degrees of freedom, and warm dark matter.
Hidden charged dark matter and chiral dark radiation
NASA Astrophysics Data System (ADS)
Ko, P.; Nagata, Natsumi; Tang, Yong
2017-10-01
In the light of recent possible tensions in the Hubble constant H0 and the structure growth rate σ8 between the Planck and other measurements, we investigate a hidden-charged dark matter (DM) model where DM interacts with hidden chiral fermions, which are charged under the hidden SU(N) and U(1) gauge interactions. The symmetries in this model assure these fermions to be massless. The DM in this model, which is a Dirac fermion and singlet under the hidden SU(N), is also assumed to be charged under the U(1) gauge symmetry, through which it can interact with the chiral fermions. Below the confinement scale of SU(N), the hidden quark condensate spontaneously breaks the U(1) gauge symmetry such that there remains a discrete symmetry, which accounts for the stability of DM. This condensate also breaks a flavor symmetry in this model and Nambu-Goldstone bosons associated with this flavor symmetry appear below the confinement scale. The hidden U(1) gauge boson and hidden quarks/Nambu-Goldstone bosons are components of dark radiation (DR) above/below the confinement scale. These light fields increase the effective number of neutrinos by δNeff ≃ 0.59 above the confinement scale for N = 2, resolving the tension in the measurements of the Hubble constant by Planck and Hubble Space Telescope if the confinement scale is ≲1 eV. DM and DR continuously scatter with each other via the hidden U(1) gauge interaction, which suppresses the matter power spectrum and results in a smaller structure growth rate. The DM sector couples to the Standard Model sector through the exchange of a real singlet scalar mixing with the Higgs boson, which makes it possible to probe our model in DM direct detection experiments. Variants of this model are also discussed, which may offer alternative ways to investigate this scenario.
A two particle hidden sector and the oscillations with photons
NASA Astrophysics Data System (ADS)
Alvarez, Pedro D.; Arias, Paola; Maldonado, Carlos
2018-01-01
We present a detailed study of the oscillations and optical properties for vacuum, in a model for the dark sector that contains axion-like particles and hidden photons. We provide bounds for the couplings versus the mass, using current results from ALPS-I and PVLAS. We also discuss the challenges for the detection of models with more than one hidden particle in light shining trough wall-like experiments.
Cosmic variance in inflation with two light scalars
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bonga, Béatrice; Brahma, Suddhasattwa; Deutsch, Anne-Sylvie
We examine the squeezed limit of the bispectrum when a light scalar with arbitrary non-derivative self-interactions is coupled to the inflaton. We find that when the hidden sector scalar is sufficiently light ( m ∼< 0.1 H ), the coupling between long and short wavelength modes from the series of higher order correlation functions (from arbitrary order contact diagrams) causes the statistics of the fluctuations to vary in sub-volumes. This means that observations of primordial non-Gaussianity cannot be used to uniquely reconstruct the potential of the hidden field. However, the local bispectrum induced by mode-coupling from these diagrams always hasmore » the same squeezed limit, so the field's locally determined mass is not affected by this cosmic variance.« less
Unified origin for baryonic visible matter and antibaryonic dark matter.
Davoudiasl, Hooman; Morrissey, David E; Sigurdson, Kris; Tulin, Sean
2010-11-19
We present a novel mechanism for generating both the baryon and dark matter densities of the Universe. A new Dirac fermion X carrying a conserved baryon number charge couples to the standard model quarks as well as a GeV-scale hidden sector. CP-violating decays of X, produced nonthermally in low-temperature reheating, sequester antibaryon number in the hidden sector, thereby leaving a baryon excess in the visible sector. The antibaryonic hidden states are stable dark matter. A spectacular signature of this mechanism is the baryon-destroying inelastic scattering of dark matter that can annihilate baryons at appreciable rates relevant for nucleon decay searches.
Hidden Sector Dark Matter Models for the Galactic Center Gamma-Ray Excess
DOE Office of Scientific and Technical Information (OSTI.GOV)
Berlin, Asher; Gratia, Pierre; Hooper, Dan
2014-07-24
The gamma-ray excess observed from the Galactic Center can be interpreted as dark matter particles annihilating into Standard Model fermions with a cross section near that expected for a thermal relic. Although many particle physics models have been shown to be able to account for this signal, the fact that this particle has not yet been observed in direct detection experiments somewhat restricts the nature of its interactions. One way to suppress the dark matter's elastic scattering cross section with nuclei is to consider models in which the dark matter is part of a hidden sector. In such models, themore » dark matter can annihilate into other hidden sector particles, which then decay into Standard Model fermions through a small degree of mixing with the photon, Z, or Higgs bosons. After discussing the gamma-ray signal from hidden sector dark matter in general terms, we consider two concrete realizations: a hidden photon model in which the dark matter annihilates into a pair of vector gauge bosons that decay through kinetic mixing with the photon, and a scenario within the generalized NMSSM in which the dark matter is a singlino-like neutralino that annihilates into a pair of singlet Higgs bosons, which decay through their mixing with the Higgs bosons of the MSSM.« less
Model-independent indirect detection constraints on hidden sector dark matter
Elor, Gilly; Rodd, Nicholas L.; Slatyer, Tracy R.; ...
2016-06-10
If dark matter inhabits an expanded ``hidden sector'', annihilations may proceed through sequential decays or multi-body final states. We map out the potential signals and current constraints on such a framework in indirect searches, using a model-independent setup based on multi-step hierarchical cascade decays. While remaining agnostic to the details of the hidden sector model, our framework captures the generic broadening of the spectrum of secondary particles (photons, neutrinos, e +e - andmore » $$\\overline{p}$$ p) relative to the case of direct annihilation to Standard Model particles. We explore how indirect constraints on dark matter annihilation limit the parameter space for such cascade/multi-particle decays. We investigate limits from the cosmic microwave background by Planck, the Fermi measurement of photons from the dwarf galaxies, and positron data from AMS-02. The presence of a hidden sector can change the constraints on the dark matter by up to an order of magnitude in either direction (although the effect can be much smaller). We find that generally the bound from the Fermi dwarfs is most constraining for annihilations to photon-rich final states, while AMS-02 is most constraining for electron and muon final states; however in certain instances the CMB bounds overtake both, due to their approximate independence on the details of the hidden sector cascade. We provide the full set of cascade spectra considered here as publicly available code with examples at http://web.mit.edu/lns/research/CascadeSpectra.html.« less
U(1) mediation of flux supersymmetry breaking
NASA Astrophysics Data System (ADS)
Grimm, Thomas W.; Klemm, Albrecht
2008-10-01
We study the mediation of supersymmetry breaking triggered by background fluxes in Type II string compactifications with Script N = 1 supersymmetry. The mediation arises due to an U(1) vector multiplet coupling to both a hidden supersymmetry breaking flux sector and a visible D-brane sector. The required internal manifolds can be constructed by non-Kähler resolutions of singular Calabi-Yau manifolds. The effective action encoding the U(1) coupling is then determined in terms of the global topological properties of the internal space. We investigate suitable local geometries for the hidden and visible sector in detail. This includes a systematic study of orientifold symmetries of del Pezzo surfaces realized in compact geometries after geometric transition. We construct compact examples admitting the key properties to realize flux supersymmetry breaking and U(1) mediation. Their toric realization allows us to analyze the geometry of curve classes and confirm the topological connection between the hidden and visible sector.
Detecting hidden particles with MATHUSLA
NASA Astrophysics Data System (ADS)
Evans, Jared A.
2018-03-01
A hidden sector containing light long-lived particles provides a well-motivated place to find new physics. The recently proposed MATHUSLA experiment has the potential to be extremely sensitive to light particles originating from rare meson decays in the very long lifetime region. In this work, we illustrate this strength with the specific example of a light scalar mixed with the standard model-like Higgs boson, a model where MATHUSLA can further probe unexplored parameter space from exotic Higgs decays. Design augmentations should be considered in order to maximize the ability of MATHUSLA to discover very light hidden sector particles.
Prospects for indirect detection of frozen-in dark matter
NASA Astrophysics Data System (ADS)
Heikinheimo, Matti; Tenkanen, Tommi; Tuominen, Kimmo
2018-03-01
We study observational consequences arising from dark matter (DM) of nonthermal origin, produced by dark freeze-out from a hidden sector heat bath. We assume this heat bath was populated by feebly coupled mediator particles, produced via a Higgs portal interaction with the Standard Model (SM). The dark sector then attained internal equilibrium with a characteristic temperature different from the SM photon temperature. We find that even if the coupling between the DM and the SM sectors is very weak, the scenario allows for indirect observational signals. We show how the expected strength of these signals depends on the temperature of the hidden sector at DM freeze-out.
Hidden sector behind the CKM matrix
NASA Astrophysics Data System (ADS)
Okawa, Shohei; Omura, Yuji
2017-08-01
The small quark mixing, described by the Cabibbo-Kobayashi-Maskawa (CKM) matrix in the standard model, may be a clue to reveal new physics around the TeV scale. We consider a simple scenario that extra particles in a hidden sector radiatively mediate the flavor violation to the quark sector around the TeV scale and effectively realize the observed CKM matrix. The lightest particle in the hidden sector, whose contribution to the CKM matrix is expected to be dominant, is a good dark matter (DM) candidate. There are many possible setups to describe this scenario, so that we investigate some universal predictions of this kind of model, focusing on the contribution of DM to the quark mixing and flavor physics. In this scenario, there is an explicit relation between the CKM matrix and flavor violating couplings, such as four-quark couplings, because both are radiatively induced by the particles in the hidden sector. Then, we can explicitly find the DM mass region and the size of Yukawa couplings between the DM and quarks, based on the study of flavor physics and DM physics. In conclusion, we show that DM mass in our scenario is around the TeV scale, and the Yukawa couplings are between O (0.01 ) and O (1 ). The spin-independent DM scattering cross section is estimated as O (10-9) [pb]. An extra colored particle is also predicted at the O (10 ) TeV scale.
Model-independent indirect detection constraints on hidden sector dark matter
DOE Office of Scientific and Technical Information (OSTI.GOV)
Elor, Gilly; Rodd, Nicholas L.; Slatyer, Tracy R.
2016-06-10
If dark matter inhabits an expanded “hidden sector”, annihilations may proceed through sequential decays or multi-body final states. We map out the potential signals and current constraints on such a framework in indirect searches, using a model-independent setup based on multi-step hierarchical cascade decays. While remaining agnostic to the details of the hidden sector model, our framework captures the generic broadening of the spectrum of secondary particles (photons, neutrinos, e{sup +}e{sup −} and p-barp) relative to the case of direct annihilation to Standard Model particles. We explore how indirect constraints on dark matter annihilation limit the parameter space for suchmore » cascade/multi-particle decays. We investigate limits from the cosmic microwave background by Planck, the Fermi measurement of photons from the dwarf galaxies, and positron data from AMS-02. The presence of a hidden sector can change the constraints on the dark matter by up to an order of magnitude in either direction (although the effect can be much smaller). We find that generally the bound from the Fermi dwarfs is most constraining for annihilations to photon-rich final states, while AMS-02 is most constraining for electron and muon final states; however in certain instances the CMB bounds overtake both, due to their approximate independence on the details of the hidden sector cascade. We provide the full set of cascade spectra considered here as publicly available code with examples at http://web.mit.edu/lns/research/CascadeSpectra.html.« less
Dynamically generated N* and {Lambda}* resonances in the hidden charm sector around 4.3 GeV
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wu Jiajun; Departamento de Fisica Teorica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Aptdo. 22085, E-46071 Valencia; Molina, R.
2011-07-15
The interactions of D-bar{Sigma}{sub c}-D-bar{Lambda}{sub c}, D-bar*{Sigma}{sub c}-D-bar*{Lambda}{sub c}, and related strangeness channels, are studied within the framework of the coupled-channel unitary approach with the local hidden gauge formalism. A series of meson-baryon dynamically generated relatively narrow N* and {Lambda}* resonances are predicted around 4.3 GeV in the hidden charm sector. We make estimates of production cross sections of these predicted resonances in p-barp collisions for the experiment of antiproton annihilation at Darmstadt (PANDA) at the forthcoming GSI Facility for Antiproton and Ion Research (FAIR) facility.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ko, P.; Tang, Yong
We show that hidden sector dark matter (DM) models with local dark gauge symmetries make a natural playground for the possible γ-ray excess from the galactic center (GC). We first discuss in detail the GC γ-ray excess in a scalar dark matter (DM) model with local Z{sub 3} symmetry which was recently proposed by the present authors. Within this model, scalar DM with mass 30–70 GeV is allowed due to the newly-opened (semi-)annihilation channels of a DM pair into dark Higgs ϕ and/or dark photon Z′ pair, and the γ-ray spectrum from the GC can be fit within this model.more » Then we argue that the GC gamma ray excess can be easily accommodated within hidden sector dark matter models where DM is stabilized by local gauge symmetries, due to the presence of dark Higgs (and also dark photon for Abelian dark gauge symmetry)« less
Searching for new physics with three-particle correlations in pp collisions at the LHC
NASA Astrophysics Data System (ADS)
Sanchis-Lozano, Miguel-Angel; Sarkisyan-Grinbaum, Edward K.
2018-06-01
New phenomena involving pseudorapidity and azimuthal correlations among final-state particles in pp collisions at the LHC can hint at the existence of hidden sectors beyond the Standard Model. In this paper we rely on a correlated-cluster picture of multiparticle production, which was shown to account for the ridge effect, to assess the effect of a hidden sector on three-particle correlations concluding that there is a potential signature of new physics that can be directly tested by experiments using well-known techniques.
Supergravity inflation free from harmful relics
NASA Astrophysics Data System (ADS)
Greene, Patrick B.; Kadota, Kenji; Murayama, Hitoshi
2003-08-01
We present a realistic supergravity inflation model that is free from the overproduction of potentially dangerous relics in cosmology, namely, moduli and gravitinos, which can lead to inconsistencies with the predictions of baryon asymmetry and nucleosynthesis. The radiative correction turns out to play a crucial role in our analysis, raising the mass of the supersymmetry breaking field to an intermediate scale. We pay particular attention to the nonthermal production of gravitinos using the nonminimal Kähler potential we obtained from loop correction. This nonthermal gravitino production is diminished, however, because of the relatively small scale of the inflaton mass and the small amplitudes of the hidden sector fields.
General gauge mediation in five dimensions
DOE Office of Scientific and Technical Information (OSTI.GOV)
McGarrie, Moritz; Russo, Rodolfo
2010-08-01
We use the ''general gauge mediation'' (GGM) formalism to describe a five-dimensional setup with an S{sup 1}/Z{sub 2} orbifold. We first consider a model independent supersymmetry breaking hidden sector on one boundary and generic chiral matter on another. Using the definition of GGM, the effects of the hidden sector are contained in a set of global symmetry current correlator functions and is mediated through the bulk. We find the gaugino, sfermion and hyperscalar mass formulas for minimal and generalized messengers in different regimes of a large, small and intermediate extra dimension. Then we use the five-dimensional GGM formalism to constructmore » a model in which an SU(5) Intriligator, Seiberg and Shih (ISS) model is located on the hidden boundary. We weakly gauge a global symmetry of the ISS model and associate it with the bulk vector superfield. Compared to four-dimensional GGM, there is a natural way to adjust the gaugino versus sfermion mass ratio by a factor (Ml){sup 2}, where M is a characteristic mass scale of the supersymmetry breaking sector and l is the length of the extra dimension.« less
Neutrino mixing in SO(10) GUTs with a non-Abelian flavor symmetry in the hidden sector
NASA Astrophysics Data System (ADS)
Smirnov, Alexei Yu.; Xu, Xun-Jie
2018-05-01
The relation between the mixing matrices of leptons and quarks, UPMNS≈VCKM†U0 , where U0 is a matrix of special forms [e.g., bimaximal (BM) and tribimaximal], can be a clue for understanding the lepton mixing and neutrino masses. It may imply the grand unification and the existence of a hidden sector with certain symmetry that generates U0 and leads to the smallness of neutrino masses. We apply the residual symmetry approach to obtain U0. The residual symmetries of both the visible and hidden sectors are Z2×Z2 . Their embedding in a unified flavor group is considered. We find that there are only several possible structures of U0, including the BM mixing and matrices with elements determined by the golden ratio. Realization of the BM scenario based on the SO(10) grand unified theory with the S4 flavor group is presented. Generic features of this scenario are discussed, in particular, the prediction of C P phase 14 4 ° ≲δCP≲21 0 ° in the minimal version.
Enqvist, Kari; Kasuya, Shinta; Mazumdar, Anupam
2003-03-07
We propose that the inflaton is coupled to ordinary matter only gravitationally and that it decays into a completely hidden sector. In this scenario both baryonic and dark matter originate from the decay of a flat direction of the minimal supersymmetric standard model, which is shown to generate the desired adiabatic perturbation spectrum via the curvaton mechanism. The requirement that the energy density along the flat direction dominates over the inflaton decay products fixes the flat direction almost uniquely. The present residual energy density in the hidden sector is typically shown to be small.
Hidden momentum of electrons, nuclei, atoms, and molecules
NASA Astrophysics Data System (ADS)
Cameron, Robert P.; Cotter, J. P.
2018-04-01
We consider the positions and velocities of electrons and spinning nuclei and demonstrate that these particles harbour hidden momentum when located in an electromagnetic field. This hidden momentum is present in all atoms and molecules, however it is ultimately canceled by the momentum of the electromagnetic field. We point out that an electron vortex in an electric field might harbour a comparatively large hidden momentum and recognize the phenomenon of hidden hidden momentum.
New prospects in fixed target searches for dark forces with the SeaQuest experiment at Fermilab
Gardner, S.; Holt, R. J.; Tadepalli, A. S.
2016-06-10
An intense 120 GeV proton beam incident on an extremely long iron target generates enormous numbers of light-mass particles that also decay within that target. If one of these particles decays to a final state with a hidden gauge boson, or if such a particle is produced as a result of the initial collision, then that weakly interacting hidden-sector particle may traverse the remainder of the target and be detected downstream through its possible decay to an e +e –, μ +μ –, or π +π – final state. These conditions can be realized through an extension of the SeaQuestmore » experiment at Fermilab, and in this initial investigation we consider how it can serve as an ultrasensitive probe of hidden vector gauge forces, both Abelian and non-Abelian. Here a light, weakly coupled hidden sector may well explain the dark matter established through astrophysical observations, and the proposed search can provide tangible evidence for its existence—or, alternatively, constrain a “sea” of possibilities.« less
Emergent gauge theories and supersymmetry: A QED primer
NASA Astrophysics Data System (ADS)
Chkareuli, J. L.
2013-04-01
We argue that a generic trigger for photon and other gauge fields to emerge as massless Nambu-Goldstone modes could be spontaneously broken supersymmetry rather than physically manifested Lorentz violation. We consider supersymmetric QED model extended by an arbitrary polynomial potential of vector superfield that induces the spontaneous SUSY violation in the visible sector. As a consequence, massless photon appears as a companion of massless photino being Goldstone fermion state in tree approximation. Remarkably, the photon masslessness appearing at tree level is further protected against radiative corrections due to the simultaneously generated special gauge invariance in the broken SUSY phase. Meanwhile, photino being mixed with another goldstino appearing from a spontaneous SUSY violation in the hidden sector largely turns into light pseudo-goldstino whose physics seems to be of special interest.
Hidden Entanglement and Unitarity at the Planck Scale
NASA Astrophysics Data System (ADS)
Arzano, Michele; Hamma, Alioscia; Severini, Simone
Attempts to go beyond the framework of local quantum field theory include scenarios in which the action of external symmetries on the quantum fields Hilbert space is deformed. We show how the Fock spaces of such theories exhibit a richer structure in their multi-particle sectors. When the deformation scale is proportional to the Planck energy, such new structure leads to the emergence of a "planckian" mode-entanglement, invisible to an observer that cannot probe the Planck scale. To the same observer, certain unitary processes would appear non-unitary. We show how entanglement transfer to the additional degrees of freedom can provide a potential way out of the black hole information paradox.
Corruption in Education Sector Development: A Suggestion for Anticipatory Strategy.
ERIC Educational Resources Information Center
Tanaka, Shinichiro
2001-01-01
Proposes an anticipatory strategy that will help protect education sector development from corruption. The strategy, which may exist as a "hidden agenda" within a project, focuses on diagnosing rather than redressing a system thought to be corrupt, adopting prevention rather than punishment, informal rather than formal approaches, and…
Hiding an elephant: heavy sterile neutrino with large mixing angle does not contradict cosmology
NASA Astrophysics Data System (ADS)
Bezrukov, F.; Chudaykin, A.; Gorbunov, D.
2017-06-01
We study a model of a keV-scale sterile neutrino with a relatively large mixing with the Standard Model sector. Usual considerations predict active generation of such particles in the early Universe, which leads to constraints from the total Dark Matter density and absence of X-ray signal from sterile neutrino decay. These bounds together may deem any attempt of creation of the keV scale sterile neutrino in the laboratory unfeasible. We argue that for models with a hidden sector coupled to the sterile neutrino these bounds can be evaded, opening new perspectives for the direct studies at neutrino experiments such as Troitsk ν-mass and KATRIN. We estimate the generation of sterile neutrinos in scenarios with the hidden sector dynamics keeping the sterile neutrinos either massless or superheavy in the early Universe. In both cases the generation by oscillations from active neutrinos in plasma is suppressed.
Dissipative dark matter halos: The steady state solution
NASA Astrophysics Data System (ADS)
Foot, R.
2018-02-01
Dissipative dark matter, where dark matter particle properties closely resemble familiar baryonic matter, is considered. Mirror dark matter, which arises from an isomorphic hidden sector, is a specific and theoretically constrained scenario. Other possibilities include models with more generic hidden sectors that contain massless dark photons [unbroken U (1 ) gauge interactions]. Such dark matter not only features dissipative cooling processes but also is assumed to have nontrivial heating sourced by ordinary supernovae (facilitated by the kinetic mixing interaction). The dynamics of dissipative dark matter halos around rotationally supported galaxies, influenced by heating as well as cooling processes, can be modeled by fluid equations. For a sufficiently isolated galaxy with a stable star formation rate, the dissipative dark matter halos are expected to evolve to a steady state configuration which is in hydrostatic equilibrium and where heating and cooling rates locally balance. Here, we take into account the major cooling and heating processes, and numerically solve for the steady state solution under the assumptions of spherical symmetry, negligible dark magnetic fields, and that supernova sourced energy is transported to the halo via dark radiation. For the parameters considered, and assumptions made, we were unable to find a physically realistic solution for the constrained case of mirror dark matter halos. Halo cooling generally exceeds heating at realistic halo mass densities. This problem can be rectified in more generic dissipative dark matter models, and we discuss a specific example in some detail.
Quasifixed points from scalar sequestering and the little hierarchy problem in supersymmetry
NASA Astrophysics Data System (ADS)
Martin, Stephen P.
2018-02-01
In supersymmetric models with scalar sequestering, superconformal strong dynamics in the hidden sector suppresses the low-energy couplings of mass dimension 2, compared to the squares of the dimension-1 parameters. Taking into account restrictions on the anomalous dimensions in superconformal theories, I point out that the interplay between the hidden and visible sector renormalizations gives rise to quasifixed point running for the supersymmetric Standard Model squared mass parameters, rather than driving them to 0. The extent to which this dynamics can ameliorate the little hierarchy problem in supersymmetry is studied. Models of this type in which the gaugino masses do not unify are arguably more natural, and are certainly more likely to be accessible, eventually, to the Large Hadron Collider.
Supersymmetric leptogenesis with a light hidden sector
NASA Astrophysics Data System (ADS)
De Simone, Andrea; Garny, Mathias; Ibarra, Alejandro; Weniger, Christoph
2010-07-01
Supersymmetric scenarios incorporating thermal leptogenesis as the origin of the observed matter-antimatter asymmetry generically predict abundances of the primordial elements which are in conflict with observations. In this paper we propose a simple way to circumvent this tension and accommodate naturally thermal leptogenesis and primordial nucleosynthesis. We postulate the existence of a light hidden sector, coupled very weakly to the Minimal Supersymmetric Standard Model, which opens up new decay channels for the next-to-lightest supersymmetric particle, thus diluting its abundance during nucleosynthesis. We present a general model-independent analysis of this mechanism as well as two concrete realizations, and describe the relevant cosmological and astrophysical bounds and implications for this dark matter scenario. Possible experimental signatures at colliders and in cosmic-ray observations are also discussed.
Asymmetric dark matter and the hadronic spectra of hidden QCD
NASA Astrophysics Data System (ADS)
Lonsdale, Stephen J.; Schroor, Martine; Volkas, Raymond R.
2017-09-01
The idea that dark matter may be a composite state of a hidden non-Abelian gauge sector has received great attention in recent years. Frameworks such as asymmetric dark matter motivate the idea that dark matter may have similar mass to the proton, while mirror matter and G ×G grand unified theories provide rationales for additional gauge sectors which may have minimal interactions with standard model particles. In this work we explore the hadronic spectra that these dark QCD models can allow. The effects of the number of light colored particles and the value of the confinement scale on the lightest stable state, the dark matter candidate, are examined in the hyperspherical constituent quark model for baryonic and mesonic states.
Limiting first-order phase transitions in dark gauge sectors from gravitational waves experiments
NASA Astrophysics Data System (ADS)
Addazi, Andrea
2017-03-01
We discuss the possibility to indirectly test first-order phase transitions of hidden sectors. We study the interesting example of a Dark Standard Model (D-SM) with a deformed parameter space in the Higgs potential. A dark electroweak phase transition can be limited from next future experiments like eLISA and DECIGO.
Hiding an elephant: heavy sterile neutrino with large mixing angle does not contradict cosmology
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bezrukov, F.; Chudaykin, A.; Gorbunov, D., E-mail: Fedor.Bezrukov@manchester.ac.uk, E-mail: chudy@ms2.inr.ac.ru, E-mail: gorby@ms2.inr.ac.ru
We study a model of a keV-scale sterile neutrino with a relatively large mixing with the Standard Model sector. Usual considerations predict active generation of such particles in the early Universe, which leads to constraints from the total Dark Matter density and absence of X-ray signal from sterile neutrino decay. These bounds together may deem any attempt of creation of the keV scale sterile neutrino in the laboratory unfeasible. We argue that for models with a hidden sector coupled to the sterile neutrino these bounds can be evaded, opening new perspectives for the direct studies at neutrino experiments such asmore » Troitsk ν-mass and KATRIN. We estimate the generation of sterile neutrinos in scenarios with the hidden sector dynamics keeping the sterile neutrinos either massless or superheavy in the early Universe. In both cases the generation by oscillations from active neutrinos in plasma is suppressed.« less
Signatures of a hidden cosmic microwave background.
Jaeckel, Joerg; Redondo, Javier; Ringwald, Andreas
2008-09-26
If there is a light Abelian gauge boson gamma' in the hidden sector its kinetic mixing with the photon can produce a hidden cosmic microwave background (HCMB). For meV masses, resonant oscillations gamma<-->gamma' happen after big bang nucleosynthesis (BBN) but before CMB decoupling, increasing the effective number of neutrinos Nnu(eff) and the baryon to photon ratio, and distorting the CMB blackbody spectrum. The agreement between BBN and CMB data provides new constraints. However, including Lyman-alpha data, Nnu(eff) > 3 is preferred. It is tempting to attribute this effect to the HCMB. The interesting parameter range will be tested in upcoming laboratory experiments.
Hidden gauged U (1 ) model: Unifying scotogenic neutrino and flavor dark matter
NASA Astrophysics Data System (ADS)
Yu, Jiang-Hao
2016-06-01
In both scotogenic neutrino and flavor dark matter models, the dark sector communicates with the standard model fermions via Yukawa portal couplings. We propose an economic scenario where the scotogenic neutrino and a flavored mediator share the same inert Higgs doublet and all are charged under a hidden gauged U (1 ) symmetry. The dark Z2 symmetry in the dark sector is regarded as the remnant of this hidden U (1 ) symmetry breaking. In particular, we investigate a dark U (1 )D [and also U (1 )B-L] model which unifies the scotogenic neutrino and top-flavored mediator. Thus dark tops and dark neutrinos are the standard model fermion partners, and the dark matter could be the inert Higgs or the lightest dark neutrino. We note that this model has rich collider signatures on dark tops, the inert Higgs and the Z' gauge boson. Moreover, the scalar associated to the U (1 )D [and also U (1 )B -L ] symmetry breaking could explain the 750 GeV diphoton excess reported by ATLAS and CMS recently.
ERIC Educational Resources Information Center
Lappalainen, Sirpa; Lahelma, Elina; Pehkonen, Leila; Isopahkala-Bouret, Ulpukka
2012-01-01
This article analyses how Finnish vocational teachers make sense of the meanings of gender in their work. The context of the study consists of the two most gender segregated environments of vocational education: the female-dominated Sector of Health and Social Services and the male-dominated Sector of Technology and Transport. Our analysis draws…
Pc -like pentaquarks in a hidden strange sector
NASA Astrophysics Data System (ADS)
Huang, Hongxia; Zhu, Xinmei; Ping, Jialun
2018-05-01
Analogous to the work of hidden charm molecular pentaquarks, we study possible hidden strange molecular pentaquarks composed of Σ (or Σ*) and K (or K*) in the framework of a quark delocalization color screening model. Our results suggest that the Σ K , Σ K*, and Σ*K* with I JP=1/2 1/2- and Σ K*, Σ*K , and Σ*K* with I JP=1/2 3/2- are all resonance states by coupling the open channels. The molecular pentaquark Σ*K with quantum numbers I JP=1/2 3/2- can be seen as a strange partner of the LHCb Pc(4380 ) state. The possibility of identifying the resonances as nucleon resonances is proposed.
High Energy Colliders and Hidden Sectors
NASA Astrophysics Data System (ADS)
Dror, Asaf Jeff
This thesis explores two dominant frontiers of theoretical physics, high energy colliders and hidden sectors. The Large Hadron Collider (LHC) is just starting to reach its maximum operational capabilities. However, already with the current data, large classes of models are being put under significant pressure. It is crucial to understand whether the (thus far) null results are a consequence of a lack of solution to the hierarchy problem around the weak scale or requires expanding the search strategy employed at the LHC. It is the duty of the current generation of physicists to design new searches to ensure that no stone is left unturned. To this end, we study the sensitivity of the LHC to the couplings in the Standard Model top sector. We find it can significantly improve the measurements on ZtRtR coupling by a novel search strategy, making use of an implied unitarity violation in such models. Analogously, we show that other couplings in the top sector can also be measured with the same technique. Furthermore, we critically analyze a set of anomalies in the LHC data and how they may appear from consistent UV completions. We also propose a technique to measure lifetimes of new colored particles with non-trivial spin. While the high energy frontier will continue to take data, it is likely the only collider of its kind for the next couple decades. On the other hand, low-energy experiments have a promising future with many new proposed experiments to probe the existence of particles well below the weak scale but with small couplings to the Standard Model. In this work we survey the different possibilities, focusingon the constraints as well as possible new hidden sector dynamics. In particular, we show that vector portals which couple to an anomalous current, e.g., baryon number, are significantly constrained from flavor changing meson decays and rare Z decays. Furthermore, we present a new mechanism for dark matter freezeout which depletes the dark sector through an out-of-equilibrium decay into the Standard Model.
Gauging hidden symmetries in two dimensions
NASA Astrophysics Data System (ADS)
Samtleben, Henning; Weidner, Martin
2007-08-01
We initiate the systematic construction of gauged matter-coupled supergravity theories in two dimensions. Subgroups of the affine global symmetry group of toroidally compactified supergravity can be gauged by coupling vector fields with minimal couplings and a particular topological term. The gauge groups typically include hidden symmetries that are not among the target-space isometries of the ungauged theory. The gaugings constructed in this paper are described group-theoretically in terms of a constant embedding tensor subject to a number of constraints which parametrizes the different theories and entirely encodes the gauged Lagrangian. The prime example is the bosonic sector of the maximally supersymmetric theory whose ungauged version admits an affine fraktur e9 global symmetry algebra. The various parameters (related to higher-dimensional p-form fluxes, geometric and non-geometric fluxes, etc.) which characterize the possible gaugings, combine into an embedding tensor transforming in the basic representation of fraktur e9. This yields an infinite-dimensional class of maximally supersymmetric theories in two dimensions. We work out and discuss several examples of higher-dimensional origin which can be systematically analyzed using the different gradings of fraktur e9.
3.55 keV line from exciting dark matter without a hidden sector
Berlin, Asher; DiFranzo, Anthony; Hooper, Dan
2015-04-24
In this study, models in which dark matter particles can scatter into a slightly heavier state which promptly decays to the lighter state and a photon (known as eXciting Dark Matter, or XDM) have been shown to be capable of generating the 3.55 keV line observed from galaxy clusters, while suppressing the flux of such a line from smaller halos, including dwarf galaxies. In most of the XDM models discussed in the literature, this up-scattering is mediated by a new light particle, and dark matter annihilations proceed into pairs of this same light state. In these models, the dark matter andmore » the mediator effectively reside within a hidden sector, without sizable couplings to the Standard Model. In this paper, we explore a model of XDM that does not include a hidden sector. Instead, the dark matter both up-scatters and annihilates through the near resonant exchange of an O(10 2) GeV pseudoscalar with large Yukawa couplings to the dark matter and smaller, but non-neglibile, couplings to Standard Model fermions. The dark matter and the mediator are each mixtures of Standard Model singlets and SU(2) W doublets. We identify parameter space in which this model can simultaneously generate the 3.55 keV line and the gamma-ray excess observed from the Galactic center, without conflicting with constraints from colliders, direct detection experiments, or observations of dwarf galaxies.« less
Non-Equilibrium Effects on the Hidden Order of Microstructured URu2Si2
NASA Astrophysics Data System (ADS)
Winter, Laurel E.; Moll, Philip J. W.; Ramshaw, B. J.; Shekhter, Arkady; Harrison, N.; Bauer, Eric D.; McDonald, Ross D.
Despite extensive studies on the heavy-fermion URu2Si2, the order parameter associated with the hidden order state has yet to be established. It is known, however that the hidden order can be suppressed with pressure and high magnetic fields, which results in the development of antiferromagnetism, and the realization of a polarized state respectively. Focused Ion Beam lithography (FIB) of URu2Si2 has enabled high magnetic field observation of quantum oscillations in the resistance, indicating the preservation of sample quality to micron scale structures. These recent advances in FIB lithography have enabled the application of unprecedented electric fields while minimizing the effects of Joule heating in highly conductive metals at cryogenic temperatures. To this end, we have been able to create the necessary sample geometry to study the effect of an electric field upon hidden order in magnetic fields up to 15 T. Preliminary results suggest that above a characteristic threshold electric field, hidden order is suppressed revealing a state with similar magnetoresistive properties to the Kondo lattice in the absence of hidden order. Work supported by US Dept. of Energy through LANL/LDRD Program and G.T. Seaborg Institute, as well as NSF DMR-1157490 and the State of Florida.
Gravitational waves from SU( N) glueball dark matter
Soni, Amarjit; Zhang, Yue
2017-05-30
Here, a hidden sector with pure non-abelian gauge symmetry is an elegant and just about the simplest model of dark matter. In this model the dark matter candidate is the lightest bound state made of the confined gauge fields, the dark glueball. In spite of its simplicity, the model has been shown to have several interesting non-standard implications in cosmology. In this work, we explore the gravitational waves from binary boson stars made of self-gravitating dark glueball fields as a natural and important consequence. We derive the dark SU(N) star mass and radius as functions of the only two fundamentalmore » parameters in the model, the glueball mass m and the number of colors N, and identify the regions that could be probed by the LIGO and future gravitational wave observatories.« less
Direct detection signatures of self-interacting dark matter with a light mediator
Nobile, Eugenio Del; Kaplinghat, Manoj; Yu, Hai-Bo
2015-10-27
Self-interacting dark matter (SIDM) is a simple and well-motivated scenario that could explain long-standing puzzles in structure formation on small scales. If the required self-interaction arises through a light mediator (with mass ~ 10 MeV) in the dark sector, this new particle must be unstable to avoid overclosing the universe. The decay of the light mediator could happen due to a weak coupling of the hidden and visible sectors, providing new signatures for direct detection experiments. The SIDM nuclear recoil spectrum is more peaked towards low energies compared to the usual case of contact interactions, because the mediator mass ismore » comparable to the momentum transfer of nuclear recoils. We show that the SIDM signal could be distinguished from that of DM particles with contact interactions by considering the time-average energy spectrum in experiments employing different target materials, or the average and modulated spectra in a single experiment. Using current limits from LUX and SuperCDMS, we also derive strong bounds on the mixing parameter between hidden and visible sector.« less
Constraints on hidden photons from current and future observations of CMB spectral distortions
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kunze, Kerstin E.; Vázquez-Mozo, Miguel Á., E-mail: kkunze@usal.es, E-mail: Miguel.Vazquez-Mozo@cern.ch
2015-12-01
A variety of beyond the standard model scenarios contain very light hidden sector U(1) gauge bosons undergoing kinetic mixing with the photon. The resulting oscillation between ordinary and hidden photons leads to spectral distortions of the cosmic microwave background. We update the bounds on the mixing parameter χ{sub 0} and the mass of the hidden photon m{sub γ'} for future experiments measuring CMB spectral distortions, such as PIXIE and PRISM/COrE. For 10{sup −14} eV∼< m{sub γ'}∼< 10{sup −13} eV, we find the kinetic mixing angle χ{sub 0} has to be less than 10{sup −8} at 95% CL. These bounds are more than an ordermore » of magnitude stronger than those derived from the COBE/FIRAS data.« less
Double Higgs mechanisms, supermassive stable particles and the vacuum energy
NASA Astrophysics Data System (ADS)
Santillán, Osvaldo P.; Gabbanelli, Luciano
2016-07-01
In the present work, a hidden scenario which cast a long-lived superheavy particle A0 and simultaneously an extremely light particle a with mass ma ˜ 10-32-10-33 eV is presented. The potential energy V (a) of the particle a models the vacuum energy density of the universe ρc ≃ 10-47GeV4. On the other hand, the A0 particle may act as superheavy dark matter at present times and the products of its decay may be observed in high energy cosmic ray events. The hidden sector proposed here include light fermions with masses near the neutrino mass mν ˜ 10-2 eV and superheavy ones with masses of the order of the GUT scale, interacting through a hidden SU(2)L interaction which also affects the ordinary sector. The construction of such combined scenario is nontrivial since the presence of light particles may spoil the stability of the heavy particle A0. However, double Higgs mechanisms may be helpful for overcoming this problem. In this context, the stability of the superheavy particle A0 is ensured due to chiral symmetry arguments elaborated in the text.
Collider detection of dark matter electromagnetic anapole moments
NASA Astrophysics Data System (ADS)
Alves, Alexandre; Santos, A. C. O.; Sinha, Kuver
2018-03-01
Dark matter that interacts with the Standard Model by exchanging photons through higher multipole interactions occurs in a wide range of both strongly and weakly coupled hidden sector models. We study the collider detection prospects of these candidates, with a focus on Majorana dark matter that couples through the anapole moment. The study is conducted at the effective field theory level with the mono-Z signature incorporating varying levels of systematic uncertainties at the high-luminosity LHC. The projected collider reach on the anapole moment is then compared to the reach coming from direct detection experiments like LZ. Finally, the analysis is applied to a weakly coupled completion with leptophilic dark matter.
Genome engineering for microbial natural product discovery.
Choi, Si-Sun; Katsuyama, Yohei; Bai, Linquan; Deng, Zixin; Ohnishi, Yasuo; Kim, Eung-Soo
2018-03-03
The discovery and development of microbial natural products (MNPs) have played pivotal roles in the fields of human medicine and its related biotechnology sectors over the past several decades. The post-genomic era has witnessed the development of microbial genome mining approaches to isolate previously unsuspected MNP biosynthetic gene clusters (BGCs) hidden in the genome, followed by various BGC awakening techniques to visualize compound production. Additional microbial genome engineering techniques have allowed higher MNP production titers, which could complement a traditional culture-based MNP chasing approach. Here, we describe recent developments in the MNP research paradigm, including microbial genome mining, NP BGC activation, and NP overproducing cell factory design. Copyright © 2018 Elsevier Ltd. All rights reserved.
Isocurvature constraints on portal couplings
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kainulainen, Kimmo; Nurmi, Sami; Vaskonen, Ville
2016-06-01
We consider portal models which are ultraweakly coupled with the Standard Model, and confront them with observational constraints on dark matter abundance and isocurvature perturbations. We assume the hidden sector to contain a real singlet scalar s and a sterile neutrino ψ coupled to s via a pseudoscalar Yukawa term. During inflation, a primordial condensate consisting of the singlet scalar s is generated, and its contribution to the isocurvature perturbations is imprinted onto the dark matter abundance. We compute the total dark matter abundance including the contributions from condensate decay and nonthermal production from the Standard Model sector. We thenmore » use the Planck limit on isocurvature perturbations to derive a novel constraint connecting dark matter mass and the singlet self coupling with the scale of inflation: m {sub DM}/GeV ∼< 0.2λ{sub s}{sup 3/8} ( H {sub *}/10{sup 11} GeV){sup −3/2}. This constraint is relevant in most portal models ultraweakly coupled with the Standard Model and containing light singlet scalar fields.« less
NASA Astrophysics Data System (ADS)
Jiang, Feng; Liu, Shulin
2018-03-01
In this paper, we present a feasibility study for detecting cracks with different hidden depths and shapes using information contained in the magnetic field excited by a rectangular coil with a rectangular cross section. First, we solve for the eigenvalues and the unknown coefficients of the magnetic vector potential by imposing artificial and natural boundary conditions. Thus, a semi-analytical solution for the magnetic field distribution around the surface of a conducting plate that contains a long hidden crack is formulated. Next, based on the proposed modelling, the influences of the different hidden depth cracks on the surface magnetic field are analysed. The results show that the horizontal and vertical components of the magnetic field near the crack are becoming weaker and that the phase information of the magnetic field can be used to qualitatively determine the hidden depth of the crack. In addition, the model is optimised to improve its accuracy in classifying crack types. The relationship between signal features and crack shapes is subsequently established. The modified model is validated by using finite element simulations, visually indicating the change in the magnetic field near the crack.
Search for Hidden-Sector Bosons in B(0)→K(*0)μ(+)μ(-) Decays.
Aaij, R; Adeva, B; Adinolfi, M; Affolder, A; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Anderson, J; Andreassi, G; Andreotti, M; Andrews, J E; Appleby, R B; Aquines Gutierrez, O; Archilli, F; d'Argent, P; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Batozskaya, V; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Bel, L J; Bellee, V; Belloli, N; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Benton, J; Berezhnoy, A; Bernet, R; Bertolin, A; Bettler, M-O; van Beuzekom, M; Bien, A; Bifani, S; Billoir, P; Bird, T; Birnkraut, A; Bizzeti, A; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Bondar, A; Bondar, N; Bonivento, W; Borghi, S; Borsato, M; Bowcock, T J V; Bowen, E; Bozzi, C; Braun, S; Britsch, M; Britton, T; Brodzicka, J; Brook, N H; Buchanan, E; Bursche, A; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Campana, P; Campora Perez, D; Capriotti, L; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carniti, P; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cauet, Ch; Cavallero, G; Cenci, R; Charles, M; Charpentier, Ph; Chefdeville, M; Chen, S; Cheung, S-F; Chiapolini, N; Chrzaszcz, M; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Cogoni, V; Cojocariu, L; Collazuol, G; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombes, M; Coquereau, S; Corti, G; Corvo, M; Couturier, B; Cowan, G A; Craik, D C; Crocombe, A; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Dall'Occo, E; Dalseno, J; David, P N Y; Davis, A; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Simone, P; Dean, C-T; Decamp, D; Deckenhoff, M; Del Buono, L; Déléage, N; Demmer, M; Derkach, D; Deschamps, O; Dettori, F; Dey, B; Di Canto, A; Di Ruscio, F; Dijkstra, H; Donleavy, S; Dordei, F; Dorigo, M; Dosil Suárez, A; Dossett, D; Dovbnya, A; Dreimanis, K; Dufour, L; Dujany, G; Dupertuis, F; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Easo, S; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; El Rifai, I; Elsasser, Ch; Ely, S; Esen, S; Evans, H M; Evans, T; Falabella, A; Färber, C; Farley, N; Farry, S; Fay, R; Ferguson, D; Fernandez Albor, V; Ferrari, F; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fohl, K; Fol, P; Fontana, M; Fontanelli, F; Forty, R; Francisco, O; Frank, M; Frei, C; Frosini, M; Fu, J; Furfaro, E; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; García Pardiñas, J; Garra Tico, J; Garrido, L; Gascon, D; Gaspar, C; Gauld, R; Gavardi, L; Gazzoni, G; Gerick, D; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianelle, A; Gianì, S; Gibson, V; Girard, O G; Giubega, L; Gligorov, V V; Göbel, C; Golubkov, D; Golutvin, A; Gomes, A; Gotti, C; Grabalosa Gándara, M; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graverini, E; Graziani, G; Grecu, A; Greening, E; Gregson, S; Griffith, P; Grillo, L; Grünberg, O; Gui, B; Gushchin, E; Guz, Yu; Gys, T; Hadavizadeh, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; He, J; Head, T; Heijne, V; Hennessy, K; Henrard, P; Henry, L; Hernando Morata, J A; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hoballah, M; Hombach, C; Hulsbergen, W; Humair, T; Hussain, N; Hutchcroft, D; Hynds, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jawahery, A; Jing, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kandybei, S; Kanso, W; Karacson, M; Karbach, T M; Karodia, S; Kecke, M; Kelsey, M; Kenyon, I R; Kenzie, M; Ketel, T; Khairullin, E; Khanji, B; Khurewathanakul, C; Klaver, S; Klimaszewski, K; Kochebina, O; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Kozeiha, M; Kravchuk, L; Kreplin, K; Kreps, M; Krocker, G; Krokovny, P; Kruse, F; Krzemien, W; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kuonen, A K; Kurek, K; Kvaratskheliya, T; Lacarrere, D; Lafferty, G; Lai, A; Lambert, D; Lanfranchi, G; Langenbruch, C; Langhans, B; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Lees, J-P; Lefèvre, R; Leflat, A; Lefrançois, J; Lemos Cid, E; Leroy, O; Lesiak, T; Leverington, B; Li, Y; Likhomanenko, T; Liles, M; Lindner, R; Linn, C; Lionetto, F; Liu, B; Liu, X; Loh, D; Longstaff, I; Lopes, J H; Lucchesi, D; Lucio Martinez, M; Luo, H; Lupato, A; Luppi, E; Lupton, O; Lusiani, A; Machefert, F; Maciuc, F; Maev, O; Maguire, K; Malde, S; Malinin, A; Manca, G; Mancinelli, G; Manning, P; Mapelli, A; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marino, P; Marks, J; Martellotti, G; Martin, M; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massafferri, A; Matev, R; Mathad, A; Mathe, Z; Matteuzzi, C; Mauri, A; Maurin, B; Mazurov, A; McCann, M; McCarthy, J; McNab, A; McNulty, R; Meadows, B; Meier, F; Meissner, M; Melnychuk, D; Merk, M; Michielin, E; Milanes, D A; Minard, M-N; Mitzel, D S; Molina Rodriguez, J; Monroy, I A; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Moron, J; Morris, A B; Mountain, R; Muheim, F; Müller, D; Müller, J; Müller, K; Müller, V; Mussini, M; Muster, B; Naik, P; Nakada, T; Nandakumar, R; Nandi, A; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, A D; Nguyen, T D; Nguyen-Mau, C; Niess, V; Niet, R; Nikitin, N; Nikodem, T; Ninci, D; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Ogilvy, S; Okhrimenko, O; Oldeman, R; Onderwater, C J G; Osorio Rodrigues, B; Otalora Goicochea, J M; Otto, A; Owen, P; Oyanguren, A; Palano, A; Palombo, F; Palutan, M; Panman, J; Papanestis, A; Pappagallo, M; Pappalardo, L L; Pappenheimer, C; Parkes, C; Passaleva, G; Patel, G D; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Petruzzo, M; Picatoste Olloqui, E; Pietrzyk, B; Pilař, T; Pinci, D; Pistone, A; Piucci, A; Playfer, S; Plo Casasus, M; Poikela, T; Polci, F; Poluektov, A; Polyakov, I; Polycarpo, E; Popov, A; Popov, D; Popovici, B; Potterat, C; Price, E; Price, J D; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Quagliani, R; Rachwal, B; Rademacker, J H; Rama, M; Rangel, M S; Raniuk, I; Rauschmayr, N; Raven, G; Redi, F; Reichert, S; Reid, M M; dos Reis, A C; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Lopez, J A; Rodriguez Perez, P; Roiser, S; Romanovsky, V; Romero Vidal, A; Ronayne, J W; Rotondo, M; Rouvinet, J; Ruf, T; Ruiz Valls, P; Saborido Silva, J J; Sagidova, N; Sail, P; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santimaria, M; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schubiger, M; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Shires, A; Siddi, B G; Silva Coutinho, R; Silva de Oliveira, L; Simi, G; Sirendi, M; Skidmore, N; Skillicorn, I; Skwarnicki, T; Smith, E; Smith, E; Smith, I T; Smith, J; Smith, M; Snoek, H; Sokoloff, M D; Soler, F J P; Soomro, F; Souza, D; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Stefkova, S; Steinkamp, O; Stenyakin, O; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Sun, L; Sutcliffe, W; Swientek, K; Swientek, S; Syropoulos, V; Szczekowski, M; Szumlak, T; T'Jampens, S; Tayduganov, A; Tekampe, T; Teklishyn, M; Tellarini, G; Teubert, F; Thomas, C; Thomas, E; van Tilburg, J; Tisserand, V; Tobin, M; Todd, J; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Torr, N; Tournefier, E; Tourneur, S; Trabelsi, K; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tuning, N; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valenti, G; Vallier, A; Vazquez Gomez, R; Vazquez Regueiro, P; Vázquez Sierra, C; Vecchi, S; Velthuis, J J; Veltri, M; Veneziano, G; Vesterinen, M; Viaud, B; Vieira, D; Vieites Diaz, M; Vilasis-Cardona, X; Vollhardt, A; Volyanskyy, D; Voong, D; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wandernoth, S; Wang, J; Ward, D R; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wright, S; Wyllie, K; Xie, Y; Xu, Z; Yang, Z; Yu, J; Yuan, X; Yushchenko, O; Zangoli, M; Zavertyaev, M; Zhang, L; Zhang, Y; Zhelezov, A; Zhokhov, A; Zhong, L; Zucchelli, S
2015-10-16
A search is presented for hidden-sector bosons, χ, produced in the decay B(0)→K*(892)(0)χ, with K*(892)(0)→K(+)π(-) and χ→μ(+)μ(-). The search is performed using pp-collision data corresponding to 3.0 fb(-1) collected with the LHCb detector. No significant signal is observed in the accessible mass range 214≤m(χ)≤4350 MeV, and upper limits are placed on the branching fraction product B(B(0)→K*(892)(0)χ)×B(χ→μ(+)μ(-)) as a function of the mass and lifetime of the χ boson. These limits are of the order of 10(-9) for χ lifetimes less than 100 ps over most of the m(χ) range, and place the most stringent constraints to date on many theories that predict the existence of additional low-mass bosons.
Radio for hidden-photon dark matter detection
Chaudhuri, Saptarshi; Graham, Peter W.; Irwin, Kent; ...
2015-10-08
We propose a resonant electromagnetic detector to search for hidden-photon dark matter over an extensive range of masses. Hidden-photon dark matter can be described as a weakly coupled “hidden electric field,” oscillating at a frequency fixed by the mass, and able to penetrate any shielding. At low frequencies (compared to the inverse size of the shielding), we find that the observable effect of the hidden photon inside any shielding is a real, oscillating magnetic field. We outline experimental setups designed to search for hidden-photon dark matter, using a tunable, resonant LC circuit designed to couple to this magnetic field. Ourmore » “straw man” setups take into consideration resonator design, readout architecture and noise estimates. At high frequencies, there is an upper limit to the useful size of a single resonator set by 1/ν. However, many resonators may be multiplexed within a hidden-photon coherence length to increase the sensitivity in this regime. Hidden-photon dark matter has an enormous range of possible frequencies, but current experiments search only over a few narrow pieces of that range. As a result, we find the potential sensitivity of our proposal is many orders of magnitude beyond current limits over an extensive range of frequencies, from 100 Hz up to 700 GHz and potentially higher.« less
Learning and inference in a nonequilibrium Ising model with hidden nodes.
Dunn, Benjamin; Roudi, Yasser
2013-02-01
We study inference and reconstruction of couplings in a partially observed kinetic Ising model. With hidden spins, calculating the likelihood of a sequence of observed spin configurations requires performing a trace over the configurations of the hidden ones. This, as we show, can be represented as a path integral. Using this representation, we demonstrate that systematic approximate inference and learning rules can be derived using dynamical mean-field theory. Although naive mean-field theory leads to an unstable learning rule, taking into account Gaussian corrections allows learning the couplings involving hidden nodes. It also improves learning of the couplings between the observed nodes compared to when hidden nodes are ignored.
Influence of super-horizon modes on correlation functions during inflation
NASA Astrophysics Data System (ADS)
Deutsch, Anne-Sylvie
2018-05-01
Coupling between sub- and super-Hubble modes can affect the locally observed statistics of our universe. In the context of Quasi-Single Field Inflation, we can compute correlation functions and derive the influence of those unobservable modes on observed correlation functions as well as on the inferred cosmological parameters. We study how different classes of diagrams affect the bispectrum in the squeezed limit; in particular, while contact-like diagrams leave the scaling between the long and short modes unchanged, exchange-like diagrams do modify the shape of the bispectrum. We show that the mass of the hidden sector field can hence be biased by an unavoidable cosmic variance that can reach a 1-σ uncertainty of Script O(10%) for a weakly non-Gaussian universe. Finally, we go beyond the bispectrum and show how couplings between unobservable and observable modes can affect generic correlation functions with arbitrary order non-derivative self-interactions.
Grüneis, Heidelinde; Penker, Marianne; Höferl, Karl-Michael
2016-01-01
Our scientific view on climate change adaptation (CCA) is unsatisfying in many ways: It is often dominated by a modernistic perspective of planned pro-active adaptation, with a selective focus on measures directly responding to climate change impacts and thus it is far from real-life conditions of those who are actually affected by climate change. Farmers have to simultaneously adapt to multiple changes. Therefore, also empirical climate change adaptation research needs a more integrative perspective on real-life climate change adaptations. This also has to consider "hidden" adaptations, which are not explicitly and directly motivated by CCA but actually contribute to the sector's adaptability to climate change. The aim of the present study is to develop and test an analytic framework that contributes to a broader understanding of CCA and to bridge the gap between scientific expertise and practical action. The framework distinguishes three types of CCA according to their climate related motivations: explicit adaptations, multi-purpose adaptations, and hidden adaptations. Although agriculture is among the sectors that are most affected by climate change, results from the case study of Tyrolean mountain agriculture show that climate change is ranked behind other more pressing "real-life-challenges" such as changing agricultural policies or market conditions. We identified numerous hidden adaptations which make a valuable contribution when dealing with climate change impacts. We conclude that these hidden adaptations have not only to be considered to get an integrative und more realistic view on CCA; they also provide a great opportunity for linking adaptation strategies to farmers' realities.
Field-induced spin-density wave beyond hidden order in URu2Si2
NASA Astrophysics Data System (ADS)
Knafo, W.; Duc, F.; Bourdarot, F.; Kuwahara, K.; Nojiri, H.; Aoki, D.; Billette, J.; Frings, P.; Tonon, X.; Lelièvre-Berna, E.; Flouquet, J.; Regnault, L.-P.
2016-10-01
URu2Si2 is one of the most enigmatic strongly correlated electron systems and offers a fertile testing ground for new concepts in condensed matter science. In spite of >30 years of intense research, no consensus on the order parameter of its low-temperature hidden-order phase exists. A strong magnetic field transforms the hidden order into magnetically ordered phases, whose order parameter has also been defying experimental observation. Here, thanks to neutron diffraction under pulsed magnetic fields up to 40 T, we identify the field-induced phases of URu2Si2 as a spin-density-wave state. The transition to the spin-density wave represents a unique touchstone for understanding the hidden-order phase. An intimate relationship between this magnetic structure, the magnetic fluctuations and the Fermi surface is emphasized, calling for dedicated band-structure calculations.
Phenomenology of pure-gauge hidden valleys at hadron colliders
NASA Astrophysics Data System (ADS)
Juknevich, Jose E.
Expectations for new physics at the LHC have been greatly influenced by the Hierarchy problem of electroweak symmetry breaking. However, there are reasons to believe that the LHC may still discover new physics, but not directly related to the resolution of the Hierarchy problem. To ensure that such a physics does not go undiscovered requires precise understanding of how new phenomena will reveal themselves in the current and future generation of particle-physics experiments. Given this fact it seems sensible to explore other approaches to this problem; we study three alternatives here. In this thesis I argue for the plausibility that the standard model is coupled, through new massive charged or colored particles, to a hidden sector whose low energy dynamics is controlled by a pure Yang-Mills theory, with no light matter. Such a sector would have numerous metastable "hidden glueballs" built from the hidden gluons. These states would decay to particles of the standard model. I consider the phenomenology of this scenario, and find formulas for the lifetimes and branching ratios of the most important of these states. The dominant decays are to two standard model gauge bosons or to fermion-antifermion pairs, or by radiative decays with photon or Higgs emission, leading to jet- and photon-rich signals, and some occasional leptons. The presence of effective operators of different mass dimensions, often competing with each other, together with a great diversity of states, leads to a great variability in the lifetimes and decay modes of the hidden glueballs. I find that most of the operators considered in this work are not heavily constrained by precision electroweak physics, therefore leaving plenty of room in the parameter space to be explored by the future experiments at the LHC. Finally, I discuss several issues on the phenomenology of the new massive particles as well as an outlook for experimental searches.
Network features of sector indexes spillover effects in China: A multi-scale view
NASA Astrophysics Data System (ADS)
Feng, Sida; Huang, Shupei; Qi, Yabin; Liu, Xueyong; Sun, Qingru; Wen, Shaobo
2018-04-01
The spillover effects among sectors are of concern for distinct market participants, who are in distinct investment horizons and concerned with the information in different time scales. In order to uncover the hidden spillover information in multi-time scales in the rapidly changing stock market and thereby offer guidance to different investors concerning distinct time scales from a system perspective, this paper constructed directional spillover effect networks for the economic sectors in distinct time scales. The results are as follows: (1) The "2-4 days" scale is the most risky scale, and the "8-16 days" scale is the least risky one. (2) The most influential and sensitive sectors are distinct in different time scales. (3) Although two sectors in the same community may not have direct spillover relations, the volatility of one sector will have a relatively strong influence on the other through indirect relations.
Whitcomb, Tiffany L
2014-01-01
The hidden curriculum is characterized by information that is tacitly conveyed to and among students about the cultural and moral environment in which they find themselves. Although the hidden curriculum is often defined as a distinct entity, tacit information is conveyed to students throughout all aspects of formal and informal curricula. This unconsciously communicated knowledge has been identified across a wide spectrum of educational environments and is known to have lasting and powerful impacts, both positive and negative. Recently, medical education research on the hidden curriculum of becoming a doctor has come to the forefront as institutions struggle with inconsistencies between formal and hidden curricula that hinder the practice of patient-centered medicine. Similarly, the complex ethical questions that arise during the practice and teaching of veterinary medicine have the potential to cause disagreement between what the institution sets out to teach and what is actually learned. However, the hidden curriculum remains largely unexplored for this field. Because the hidden curriculum is retained effectively by students, elucidating its underlying messages can be a key component of program refinement. A review of recent literature about the hidden curriculum in a variety of fields, including medical education, will be used to explore potential hidden curricula in veterinary medicine and draw attention to the need for further investigation.
Infinite hidden conditional random fields for human behavior analysis.
Bousmalis, Konstantinos; Zafeiriou, Stefanos; Morency, Louis-Philippe; Pantic, Maja
2013-01-01
Hidden conditional random fields (HCRFs) are discriminative latent variable models that have been shown to successfully learn the hidden structure of a given classification problem (provided an appropriate validation of the number of hidden states). In this brief, we present the infinite HCRF (iHCRF), which is a nonparametric model based on hierarchical Dirichlet processes and is capable of automatically learning the optimal number of hidden states for a classification task. We show how we learn the model hyperparameters with an effective Markov-chain Monte Carlo sampling technique, and we explain the process that underlines our iHCRF model with the Restaurant Franchise Rating Agencies analogy. We show that the iHCRF is able to converge to a correct number of represented hidden states, and outperforms the best finite HCRFs--chosen via cross-validation--for the difficult tasks of recognizing instances of agreement, disagreement, and pain. Moreover, the iHCRF manages to achieve this performance in significantly less total training, validation, and testing time.
Equal Opportunity and the Montessori Magnet School.
ERIC Educational Resources Information Center
Haines, Annette M.
1995-01-01
Discusses the inequalities and hidden curriculum of public education and the role that the Montessori approach can play in revolutionizing educational assumptions, values, and conventions as it expands in the public sector. Suggests that Montessori models for self-discipline, meaningful work, choice, respect, and holistic psychology provide a…
Carelessness: A Hidden Doxa of Higher Education
ERIC Educational Resources Information Center
Lynch, Kathleen
2010-01-01
This article explores the implications of new public sector "reforms" for the culture of higher education. It argues that a culture of carelessness, grounded in Cartesian rationalism, has been exacerbated by new managerialism. The article challenges a prevailing sociological assumption that the character of higher education culture is primarily…
Looking for the WIMP next door
NASA Astrophysics Data System (ADS)
Evans, Jared A.; Gori, Stefania; Shelton, Jessie
2018-02-01
We comprehensively study experimental constraints and prospects for a class of minimal hidden sector dark matter (DM) models, highlighting how the cosmological history of these models informs the experimental signals. We study simple `secluded' models, where the DM freezes out into unstable dark mediator states, and consider the minimal cosmic history of this dark sector, where coupling of the dark mediator to the SM was sufficient to keep the two sectors in thermal equilibrium at early times. In the well-motivated case where the dark mediators couple to the Standard Model (SM) via renormalizable interactions, the requirement of thermal equilibrium provides a minimal, UV-insensitive, and predictive cosmology for hidden sector dark matter. We call DM that freezes out of a dark radiation bath in thermal equilibrium with the SM a WIMP next door, and demonstrate that the parameter space for such WIMPs next door is sharply defined, bounded, and in large part potentially accessible. This parameter space, and the corresponding signals, depend on the leading interaction between the SM and the dark mediator; we establish it for both Higgs and vector portal interactions. In particular, there is a cosmological lower bound on the portal coupling strength necessary to thermalize the two sectors in the early universe. We determine this thermalization floor as a function of equilibration temperature for the first time. We demonstrate that direct detection experiments are currently probing this cosmological lower bound in some regions of parameter space, while indirect detection signals and terrestrial searches for the mediator cut further into the viable parameter space. We present regions of interest for both direct detection and dark mediator searches, including motivated parameter space for the direct detection of sub-GeV DM.
Hidden Curriculum as One of Current Issue of Curriculum
ERIC Educational Resources Information Center
Alsubaie, Merfat Ayesh
2015-01-01
There are several issues in the education system, especially in the curriculum field that affect education. Hidden curriculum is one of current controversial curriculum issues. Many hidden curricular issues are the result of assumptions and expectations that are not formally communicated, established, or conveyed within the learning environment.…
NASA Technical Reports Server (NTRS)
Krauss, L. M.; Guth, A. H.; Spergel, D. N.; Field, G. B.; Press, W. H.
1986-01-01
The possible production of shadow matter during the period of cosmic inflation is considered. The superstring theory of Gross et al. (1985), which results in a gauge group E8 x E8, could, at low energies, result in the existence of two sectors: an observed sector associated with all familiar particles and interactions, and a hidden one whose particles couple only through gravitational interactions with ordinary matter. It is demonstrated here that if, in the early universe, an inflationary phase is associated with the breaking of one of the symmetries in the E8 x E8 theory, this strongly constrains the physics of both sectors if shadow matter is to be the missing mass in the universe.
Extended Friedberg-Lee hidden symmetries, quark masses, and CP violation with four generations
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bar-Shalom, Shaouly; Oaknin, David; Soni, Amarjit
2009-07-01
Motivated in part by the several observed anomalies involving CP asymmetries of B and B{sub s} decays, we consider the standard model with a 4th sequential family (SM4) which seems to offer a rather simple resolution. We initially assume T-invariance by taking the up and down-quark 4x4 mass matrix to be real. Following Friedberg and Lee (FL), we then impose a hidden symmetry on the unobserved (hidden) up and down-quark SU(2) states. The hidden symmetry for four generations ensures the existence of two zero-mass eigenstates, which we take to be the (u,c) and (d,s) states in the up and down-quarkmore » sectors, respectively. Then, we simultaneously break T-invariance and the hidden symmetry by introducing two phase factors in each sector. This breaking mechanism generates the small quark masses m{sub u}, m{sub c} and m{sub d}, m{sub s}, which, along with the orientation of the hidden symmetry, determine the size of CP-violation in the SM4. For illustration we choose a specific physical picture for the hidden symmetry and the breaking mechanism that reproduces the observed quark masses, mixing angles and CP-violation, and at the same time allows us to further obtain very interesting relations/predictions for the mixing angles of t and t'. For example, with this choice we get V{sub td}{approx}(V{sub cb}/V{sub cd}-V{sub ts}/V{sub us})+O({lambda}{sup 2}) and V{sub t{sup '}}{sub b}{approx}V{sub t{sup '}}{sub d}{center_dot}(V{sub cb}/V{sub cd}), V{sub tb{sup '}}{approx}V{sub t{sup '}}{sub d}{center_dot}(V{sub ts}/V{sub us}), implying that V{sub t{sup '}}{sub d}>V{sub t{sup '}}{sub b}, V{sub tb{sup '}}. We furthermore find that the Cabibbo angle is related to the orientation of the hidden symmetry and that the key CP-violating quantity of our model at high energies, J{sub SM4}{identical_to}Im(V{sub tb}V{sub t{sup '}}{sub b}*V{sub t{sup '}}{sub b{sup '}}V{sub tb{sup '}}*), which is the high-energy analogue of the Jarlskog invariant of the SM, is proportional to the light-quark masses and the measured Cabibbo-Kobayashi-Maskawa quark-mixing matrix angles: |J{sub SM4}|{approx}A{sup 3}{lambda}{sup 5}x({radical}(m{sub u}/m{sub t})+{radical}(m{sub c}/m{sub t{sup '}})-{radical}(m{sub d}/m{sub b})+{radical}(m{sub s}/m{sub b{sup '}})){approx}10{sup -5}, where A{approx}0.81 and {lambda}=0.2257 are the Wolfenstein parameters. Other choices for the orientation of the hidden symmetry and/or the breaking mechanism may lead to different physical outcomes. A general solution, obtained numerically, will be presented in a forthcoming paper.« less
Extended Friedberg-Lee hidden symmetries, quark masses,and CP violation with four generations
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bar-Shalom, S.; Soni, A.; Oaknin, D.
2009-07-16
Motivated in part by the several observed anomalies involving CP asymmetries of B and B{sub s} decays, we consider the standard model with a 4th sequential family (SM4) which seems to offer a rather simple resolution. We initially assume T-invariance by taking the up and down-quark 4 x 4 mass matrix to be real. Following Friedberg and Lee (FL), we then impose a hidden symmetry on the unobserved (hidden) up and down-quark SU(2) states. The hidden symmetry for four generations ensures the existence of two zero-mass eigenstates, which we take to be the (u,c) and (d,s) states in the upmore » and down-quark sectors, respectively. Then, we simultaneously break T-invariance and the hidden symmetry by introducing two phase factors in each sector. This breaking mechanism generates the small quark masses m{sub u}, m{sub c} and m{sub d}, m{sub s}, which, along with the orientation of the hidden symmetry, determine the size of CP-violation in the SM4. For illustration we choose a specific physical picture for the hidden symmetry and the breaking mechanism that reproduces the observed quark masses, mixing angles and CP-violation, and at the same time allows us to further obtain very interesting relations/predictions for the mixing angles of t and t'. For example, with this choice we get V{sub td} {approx} (V{sub cb}/V{sub cd}-V{sub ts}/V{sub us}) + O({lambda}{sup 2}) and V{sub t'b}{approx}V{sub t'd{sm_bullet}}(V{sub cb}/V{sub cd}), V{sub tb'}V{sub t'd{sm_bullet}}(V{sub ts}/V{sub us}), implying that V{sub t'd} > V{sub t'b}, V{sub tb'}. We furthermore find that the Cabibbo angle is related to the orientation of the hidden symmetry and that the key CP-violating quantity of our model at high energies, J{sub SM4} {triple_bond} Im(V{sub tb}V{sub t'b*}V{sub t'b{prime}}V{sub tb'*}), which is the high-energy analogue of the Jarlskog invariant of the SM, is proportional to the light-quark masses and the measured Cabibbo-Kobayashi-Maskawa quark-mixing matrix angles: |J{sub SM4}|A{sup 3}{lambda}{sup 5} x ({radical}(m{sub u}/m{sub t}) + {radical}m{sub c}/m{sub t'}-{radical}(m{sub d}/m{sub b}) + {radical}m{sub s}/m{sub b'}) {approx} 10{sup -5}, where A {approx} 0.81 and {lambda} = 0.2257 are the Wolfenstein parameters. Other choices for the orientation of the hidden symmetry and/or the breaking mechanism may lead to different physical outcomes. A general solution, obtained numerically, will be presented in a forthcoming paper.« less
URu2Si2 under intense magnetic fields: From hidden order to spin-density wave
NASA Astrophysics Data System (ADS)
Knafo, W.; Aoki, D.; Scheerer, G. W.; Duc, F.; Bourdarot, F.; Kuwahara, K.; Nojiri, H.; Regnault, L.-P.; Flouquet, J.
2018-05-01
A review of recent state-of-the-art pulsed field experiments performed on URu2Si2 under a magnetic field applied along its easy magnetic axis c is given. Resistivity, magnetization, magnetic susceptibility, Shubnikov-de Haas, and neutron diffraction experiments are presented, permitting to emphasize the relationship between Fermi surface reconstructions, the destruction of the hidden-order and the appearance of a spin-density wave state in a high magnetic field.
Electric Field Effects on the Hidden Order of Microstructured URu 2Si 2
DOE Office of Scientific and Technical Information (OSTI.GOV)
Stritzinger, Laurel Elaine Winter; Mcdonald, Ross David; Harrison, Neil
2017-03-23
Despite being studied for over 30 years there is still continual interest in they heavy-fermion URu 2Si 2 due largely in part to the still disagreed upon origin of the so-called hidden-order (HO) state that arises below THO = 17.5 K. While both the application of pressure and high magnetic fields have been shown to suppress the HO state, one mechanism that has yet to be explored is the application of an electric field, most likely due to the difficulty of measuring such an effect in a metal. To overcome this challenge we have used focused ion beam (FIB) lithographymore » to obtain the necessary sample geometry to create an electric field across a small section of the sample by applying a voltage. Our results suggest that at low temperatures the application of an electric field is able to suppress the hidden order state.« less
Deconstructing zero: resurgence, supersymmetry and complex saddles
Dunne, Gerald V.; Ünsal, Mithat
2016-12-01
We explain how a vanishing, or truncated, perturbative expansion, such as often arises in semi-classically tractable supersymmetric theories, can nevertheless be related to fluctuations about non-perturbative sectors via resurgence. We also demonstrate that, in the same class of theories, the vanishing of the ground state energy (unbroken supersymmetry) can be attributed to the cancellation between a real saddle and a complex saddle (with hidden topological angle π), and positivity of the ground state energy (broken supersymmetry) can be interpreted as the dominance of complex saddles. In either case, despite the fact that the ground state energy is zero to allmore » orders in perturbation theory, all orders of fluctuations around non-perturbative saddles are encoded in the perturbative E (N, g). Finally, we illustrate these ideas with examples from supersymmetric quantum mechanics and quantum field theory.« less
Jafree, Sara Rizvi; Zakar, Rubeena; Fischer, Florian; Zakar, Muhammad Zakria
2015-03-19
The importance of the hidden curriculum is recognised as a practical training ground for the absorption of medical ethics by healthcare professionals. Pakistan's healthcare sector is hampered by the exclusion of ethics from medical and nursing education curricula and the absence of monitoring of ethical violations in the clinical setting. Nurses have significant knowledge of the hidden curriculum taught during clinical practice, due to long working hours in the clinic and front-line interaction with patients and other practitioners. The means of inquiry for this study was qualitative, with 20 interviews and four focus group discussions used to identify nurses' clinical experiences of ethical violations. Content analysis was used to discover sub-categories of ethical violations, as perceived by nurses, within four pre-defined categories of nursing codes of ethics: 1) professional guidelines and integrity, 2) patient informed consent, 3) patient rights, and 4) co-worker coordination for competency, learning and patient safety. Ten sub-categories of ethical violations were found: nursing students being used as adjunct staff, nurses having to face frequent violence in the hospital setting, patient reluctance to receive treatment from nurses, the near-absence of consent taken from patients for most non-surgical medical procedures, the absence of patient consent taking for receiving treatment from student nurses, the practice of patient discrimination on the basis of a patient's socio-demographic status, nurses withdrawing treatment out of fear for their safety, a non-learning culture and, finally, blame-shifting and non-reportage of errors. Immediate and urgent attention is required to reduce ethical violations in the healthcare sector in Pakistan through collaborative efforts by the government, the healthcare sector, and ethics regulatory bodies. Also, changes in socio-cultural values in hospital organisation, public awareness of how to conveniently report ethical violations by practitioners and public perceptions of nurse identity are needed.
Mystery of the Hidden Cosmos [Complex Dark Matter
Dobrescu, Bogdan A.; Lincoln, Don
2015-06-16
Scientists know there must be more matter in the universe than what is visible. Searches for this dark matter have focused on a single unseen particle, but decades of experiments have been unsuccessful at finding it. Exotic possibilities for dark matter are looking increasingly plausible. Rather than just one particle, dark matter could contain an entire world of particles and forces that barely interact with normal matter. Complex dark matter could form dark atoms and molecules and even clump together to make hidden galactic disks that overlap with the spiral arms of the Milky Way and other galaxies. Experiments aremore » under way to search for evidence of such a dark sector.« less
Exposing the dark sector with future Z factories
NASA Astrophysics Data System (ADS)
Liu, Jia; Wang, Lian-Tao; Wang, Xiao-Ping; Xue, Wei
2018-05-01
We investigate the prospects of searching dark sector models via exotic Z -boson decay at future e+e- colliders with Giga Z and Tera Z options. Four general categories of dark sector models, Higgs portal dark matter, vector-portal dark matter, inelastic dark matter, and axionlike particles, are considered. Focusing on channels motivated by the dark sector models, we carry out a model-independent study of the sensitivities of Z factories in probing exotic decays. The limits on branching ratios of the exotic Z decay are typically O (10-6- 10-8.5) for the Giga Z and O (10-7.5- 10-11) for the Tera Z , and they are compared with the projection for the high luminosity LHC. We demonstrate that future Z factories can provide its unique and leading sensitivity and highlight the complementarity with other experiments, including the indirect and direct dark matter search limits and the existing collider limits. Future Z factories will play a leading role in uncovering the hidden sector of the Universe in the future.
Violence against Women Students in the UK: Time to Take Action
ERIC Educational Resources Information Center
Phipps, Alison; Smith, Geraldine
2012-01-01
Sexual and gendered violence in the education sector is a worldwide concern, but in the UK it has been marginalised in research and policy. In this paper we present findings from the National Union of Students' study "Hidden Marks", the first nationwide survey of women students' experiences of violence. This research established high…
Force, torque, linear momentum, and angular momentum in classical electr odynamics
NASA Astrophysics Data System (ADS)
Mansuripur, Masud
2017-10-01
The classical theory of electrodynamics is built upon Maxwell's equations and the concepts of electromagnetic (EM) field, force, energy, and momentum, which are intimately tied together by Poynting's theorem and by the Lorentz force law. Whereas Maxwell's equations relate the fields to their material sources, Poynting's theorem governs the flow of EM energy and its exchange between fields and material media, while the Lorentz law regulates the back-and-forth transfer of momentum between the media and the fields. An alternative force law, first proposed by Einstein and Laub, exists that is consistent with Maxwell's equations and complies with the conservation laws as well as with the requirements of special relativity. While the Lorentz law requires the introduction of hidden energy and hidden momentum in situations where an electric field acts on a magnetized medium, the Einstein-Laub (E-L) formulation of EM force and torque does not invoke hidden entities under such circumstances. Moreover, total force/torque exerted by EM fields on any given object turns out to be independent of whether the density of force/torque is evaluated using the law of Lorentz or that of Einstein and Laub. Hidden entities aside, the two formulations differ only in their predicted force and torque distributions inside matter. Such differences in distribution are occasionally measurable, and could serve as a guide in deciding which formulation, if either, corresponds to physical reality.
Enhanced axion-photon coupling in GUT with hidden photon
NASA Astrophysics Data System (ADS)
Daido, Ryuji; Takahashi, Fuminobu; Yokozaki, Norimi
2018-05-01
We show that the axion coupling to photons can be enhanced in simple models with a single Peccei-Quinn field, if the gauge coupling unification is realized by a large kinetic mixing χ = O (0.1) between hypercharge and unbroken hidden U(1)H. The key observation is that the U(1)H gauge coupling should be rather strong to induce such large kinetic mixing, leading to enhanced contributions of hidden matter fields to the electromagnetic anomaly. We find that the axion-photon coupling is enhanced by about a factor of 10-100 with respect to the GUT-axion models with E / N = 8 / 3.
Behavioral and Temporal Pattern Detection Within Financial Data With Hidden Information
2012-02-01
probabilistic pattern detector to monitor the pattern. 15. SUBJECT TERMS Runtime verification, Hidden data, Hidden Markov models, Formal specifications...sequences in many other fields besides financial systems [L, TV, LC, LZ ]. Rather, the technique suggested in this paper is positioned as a hybrid...operation of the pattern detector . Section 7 describes the operation of the probabilistic pattern-matching monitor, and section 8 describes three
Secret Lives of the Hidden Physicists---from Spandex to Spintronics
NASA Astrophysics Data System (ADS)
White, Gary
2006-10-01
What is a physicist? A case is made for defining a physicist as anyone with a bachelor's degree (or higher) in physics. Under this definition, a large fraction of physicists are hidden, that is, they have left, or never belonged to, the traditional lot of Ph.D. academicians. Data from the Statistical Research Center at the American Institute of Physics and from a survey of members of the national physics honor society, Sigma Pi Sigma, show the vast array of actual career paths taken by physicists. From spandex to blackberries to bioinformatics to flight control to wind energy to spintronics, physicists can be found in nearly every job sector in some of the coolest and most farfetched careers imaginable.
Hafferty, Frederic W; Martimianakis, Maria Athina
2017-11-07
In this Commentary, the authors explore the scoping review by Lawrence and colleagues by challenging their conclusion that with over 25 years' worth of "ambiguous and seemingly ubiquitous use" of the hidden curriculum construct in health professions education scholarship, it is time to either move to a more uniform definitional foundation or abandon the term altogether. The commentary authors counter these remedial propositions by foregrounding the importance of theoretical diversity and the conceptual richness afforded when the hidden curriculum construct is used as an entry point for studying the interstitial space between the formal and a range of other-than-formal domains of learning. Further, they document how tightly-delimited scoping strategies fail to capture the wealth of educational scholarship that operates within a hidden curriculum framework, including "hidden" hidden curriculum articles, studies that employ alternative constructs, and investigations that target important tacit socio-cultural influences on learners and faculty without formally deploying the term. They offer examples of how the hidden curriculum construct, while undergoing significant transformation in its application within the field of health professions education, has created the conceptual foundation for the application of a number of critical perspectives that make visible the field's political investments in particular forms of knowing and associated practices. Finally, the commentary authors invite readers to consider the methodological promise afforded by conceptual heterogeneity, particularly strands of scholarship that resituate the hidden curriculum concept within the magically expansive dance of social relationships, social learning, and social life that form the learning environments of health professions education.
Sakurai Prize: Why the Higgs Boson data implies an M-theory world
NASA Astrophysics Data System (ADS)
Kane, Gordon
2017-01-01
Compactifying 11D M-theory on a 7D G2 manifold automatically gives a supersymmetric 4D relativistic quantum field theory. The supersymmetry is softly broken by gluino condensation of the largest gauge group hidden sector, which runs fastest. The resulting gravitino mass is about 40 TeV, and the scalar masses and trilinears of the soft breaking Lagrangian have similar values. All solutions having electroweak symmetry breaking are in the two doublet decoupling region. The coefficient λ of the effective Higgs potential is calculable and determines Mh/MZ. Using the most recent match and run methods, and running down to the TeV scale gives Mh = 126 GeV, and decay BR within a few per cent of the SM Higgs. This was reported in summer 2011, before LHC data, though the result does not depend on any adjustable parameters so it would be unchanged whenever it was reported.
ERIC Educational Resources Information Center
Caraher, Martin; Dowler, Elizabeth
2007-01-01
Background and Objective: Successive governments have promoted local action to address food components of public health. This article presents findings from research commissioned by the (then) London NHS Office, scoping the range of food projects in the London area, and the potential challenges to public health practice. Methods: Research followed…
Hidden sector monopole, vector dark matter and dark radiation with Higgs portal
DOE Office of Scientific and Technical Information (OSTI.GOV)
Baek, Seungwon; Ko, P.; Park, Wan-Il, E-mail: sbaek1560@gmail.com, E-mail: pko@kias.re.kr, E-mail: wipark@kias.re.kr
2014-10-01
We show that the 't Hooft-Polyakov monopole model in the hidden sector with Higgs portal interaction makes a viable dark matter model, where monopole and massive vector dark matter (VDM) are stable due to topological conservation and the unbroken subgroup U(1 {sub X}. We show that, even though observed CMB data requires the dark gauge coupling to be quite small, a right amount of VDM thermal relic can be obtained via s-channel resonant annihilation for the mass of VDM close to or smaller than the half of SM higgs mass, thanks to Higgs portal interaction. Monopole relic density turns outmore » to be several orders of magnitude smaller than the observed dark matter relic density. Direct detection experiments, particularly, the projected XENON1T experiment, may probe the parameter space where the dark Higgs is lighter than ∼< 50 GeV. In addition, the dark photon associated with the unbroken U(1 {sub X} contributes to the radiation energy density at present, giving Δ N{sub eff}{sup ν} ∼ 0.1 as the extra relativistic neutrino species.« less
Toward electroweak scale cold dark matter with local dark gauge symmetry and beyond the DM EFT
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ko, Pyungwon, E-mail: pko@kias.re.kr
2016-06-21
In this talk, I describe a class of electroweak (EW) scale dark matter (DM) models where its stability or longevity are the results of underlying dark gauge symmetries: stable due to unbroken local dark gauge symmetry or topology, or long-lived due to the accidental global symmetry of dark gauge theories. Compared with the usual phenomenological dark matter models (including DM EFT or simplified DM models), DM models with local dark gauge symmetries include dark gauge bosons, dark Higgs bosons and sometimes excited dark matter. And dynamics among these fields are completely fixed by local gauge principle. The idea of singletmore » portals including the Higgs portal can thermalize these hidden sector dark matter very efficiently, so that these DM could be easily thermal DM. I also discuss the limitation of the usual DM effective field theory or simplified DM models without the full SM gauge symmetry, and emphasize the importance of the full SM gauge symmetry and renormalizability especially for collider searches for DM.« less
NASA Astrophysics Data System (ADS)
Abdolmohammadi, Hamid Reza; Khalaf, Abdul Jalil M.; Panahi, Shirin; Rajagopal, Karthikeyan; Pham, Viet-Thanh; Jafari, Sajad
2018-06-01
Nowadays, designing chaotic systems with hidden attractor is one of the most interesting topics in nonlinear dynamics and chaos. In this paper, a new 4D chaotic system is proposed. This new chaotic system has no equilibria, and so it belongs to the category of systems with hidden attractors. Dynamical features of this system are investigated with the help of its state-space portraits, bifurcation diagram, Lyapunov exponents diagram, and basin of attraction. Also a hardware realisation of this system is proposed by using field programmable gate arrays (FPGA). In addition, an electronic circuit design for the chaotic system is introduced.
Choi, Soo -Min; Hochberg, Yonit; Kuflik, Eric; ...
2017-10-24
Strongly Interacting Massive Particles (SIMPs) have recently been proposed as light thermal dark matter relics. Here we consider an explicit realization of the SIMP mechanism in the form of vector SIMPs arising from an SU(2) X hidden gauge theory, where the accidental custodial symmetry protects the stability of the dark matter. We propose several ways of equilibrating the dark and visible sectors in this setup. In particular, we show that a light dark Higgs portal can maintain thermal equilibrium between the two sectors, as can a massive dark vector portal with its generalized Chern-Simons couplings to the vector SIMPs, allmore » while remaining consistent with experimental constraints.« less
NASA Astrophysics Data System (ADS)
Choi, Soo-Min; Hochberg, Yonit; Kuflik, Eric; Lee, Hyun Min; Mambrini, Yann; Murayama, Hitoshi; Pierre, Mathias
2017-10-01
Strongly Interacting Massive Particles (SIMPs) have recently been proposed as light thermal dark matter relics. Here we consider an explicit realization of the SIMP mechanism in the form of vector SIMPs arising from an SU(2) X hidden gauge theory, where the accidental custodial symmetry protects the stability of the dark matter. We propose several ways of equilibrating the dark and visible sectors in this setup. In particular, we show that a light dark Higgs portal can maintain thermal equilibrium between the two sectors, as can a massive dark vector portal with its generalized Chern-Simons couplings to the vector SIMPs, all while remaining consistent with experimental constraints.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Choi, Soo -Min; Hochberg, Yonit; Kuflik, Eric
Strongly Interacting Massive Particles (SIMPs) have recently been proposed as light thermal dark matter relics. Here we consider an explicit realization of the SIMP mechanism in the form of vector SIMPs arising from an SU(2) X hidden gauge theory, where the accidental custodial symmetry protects the stability of the dark matter. We propose several ways of equilibrating the dark and visible sectors in this setup. In particular, we show that a light dark Higgs portal can maintain thermal equilibrium between the two sectors, as can a massive dark vector portal with its generalized Chern-Simons couplings to the vector SIMPs, allmore » while remaining consistent with experimental constraints.« less
Hidden acoustic information revealed by intentional nonlinearity
NASA Astrophysics Data System (ADS)
Dowling, David R.
2017-11-01
Acoustic waves are omnipresent in modern life and are well described by the linearized equations of fluid dynamics. Once generated, acoustic waves carry and collect information about their source and the environment through which they propagate, respectively, and this information may be retrieved by analyzing recordings of these waves. Because of this, acoustics is the primary means for observation, surveillance, reconnaissance, and remote sensing in otherwise opaque environments, such as the Earth's oceans and crust, and the interior of the human body. For such information-retrieval tasks, acoustic fields are nearly always interrogated within their recorded frequency range or bandwidth. However, this frequency-range restriction is not general; acoustic fields may also carry (hidden) information at frequencies outside their bandwidth. Although such a claim may seem counter intuitive, hidden acoustic-field information can be revealed by re-introducing a marquee trait of fluid dynamics: nonlinearity. In particular, an intentional quadratic nonlinearity - a form of intra-signal heterodyning - can be used to obtain acoustic field information at frequencies outside a recorded acoustic field's bandwidth. This quadratic nonlinearity enables a variety of acoustic remote sensing applications that were long thought to be impossible. In particular, it allows the detrimental effects of sparse recordings and random scattering to be suppressed when the original acoustic field has sufficient bandwidth. In this presentation, the topic is developed heuristically, with a just brief exposition of the relevant mathematics. Hidden acoustic field information is then revealed from simulated and measured acoustic fields in simple and complicated acoustic environments involving frequencies from a few Hertz to more than 100 kHz, and propagation distances from tens of centimeters to hundreds of kilometers. Sponsored by ONR, NAVSEA, and NSF.
[Motor asymmetry and learning new skills in animals].
Budilin, S Iu; Pletneva, E V; Ioffe, M E; Arsen'ev, G N
2014-01-01
The aim was to examine the relationship between the ability to learn new motor skills and preference to the right or left front paw when performing manipulation movements in rats. As a new skill used the Morris water maze, in which the animals are initially trained to detect platform hidden under water at the swim of the sector of the opposite platform, and then when sailing from sectors on the left or the right of the platform. Preference paw was determined by using the taking of animal food from a narrow horizontal tube and, accordingly, the rats were divided into left-handedness and right-handedness. We found that when changing the place of launch, that is the first voyage from the left or right of the sector, are right-handed, unlike left-handed, spent significantly more time to find the platform.
Cosmic selection rule for the glueball dark matter relic density
NASA Astrophysics Data System (ADS)
Soni, Amarjit; Xiao, Huangyu; Zhang, Yue
2017-10-01
We point out a unique mechanism to produce the relic abundance for the glueball dark matter from a gauged SU (N )d hidden sector which is bridged to the standard model sector through heavy vectorlike quarks colored under gauge interactions from both sides. A necessary ingredient of our assumption is that the vectorlike quarks, produced either thermally or nonthermally, are abundant enough to dominate the universe for some time in the early universe. They later undergo dark color confinement and form unstable vectorlike-quarkonium states which annihilate decay and reheat the visible and dark sectors. The ratio of entropy dumped into two sectors and the final energy budget in the dark glueballs is only determined by low energy parameters, including the intrinsic scale of the dark SU (N )d , Λd, and number of dark colors, Nd, but depend weakly on parameters in the ultraviolet such as the vectorlike quark mass or the initial condition. We call this a cosmic selection rule for the glueball dark matter relic density.
Thermal dark matter from a highly decoupled sector
Berlin, Asher; Hooper, Dan; Krnjaic, Gordan
2016-11-17
It has recently been shown that if the dark matter is in thermal equilibrium with a sector that is highly decoupled from the Standard Model, it can freeze out with an acceptable relic abundance, even if the dark matter is as heavy as ~1–100 PeV. In such scenarios, both the dark and visible sectors are populated after inflation, but with independent temperatures. The lightest particle in the dark sector will be generically long-lived and can come to dominate the energy density of the Universe. Upon decaying, these particles can significantly reheat the visible sector, diluting the abundance of dark mattermore » and thus allowing for dark matter particles that are much heavier than conventional WIMPs. In this study, we present a systematic and pedagogical treatment of the cosmological history in this class of models, emphasizing the simplest scenarios in which a dark matter candidate annihilates into hidden sector particles which then decay into visible matter through the vector, Higgs, or lepton portals. In each case, we find ample parameter space in which very heavy dark matter particles can provide an acceptable thermal relic abundance. We also discuss possible extensions of models featuring these dynamics.« less
Thermal dark matter from a highly decoupled sector
DOE Office of Scientific and Technical Information (OSTI.GOV)
Berlin, Asher; Hooper, Dan; Krnjaic, Gordan
It has recently been shown that if the dark matter is in thermal equilibrium with a sector that is highly decoupled from the Standard Model, it can freeze out with an acceptable relic abundance, even if the dark matter is as heavy as ~1–100 PeV. In such scenarios, both the dark and visible sectors are populated after inflation, but with independent temperatures. The lightest particle in the dark sector will be generically long-lived and can come to dominate the energy density of the Universe. Upon decaying, these particles can significantly reheat the visible sector, diluting the abundance of dark mattermore » and thus allowing for dark matter particles that are much heavier than conventional WIMPs. In this study, we present a systematic and pedagogical treatment of the cosmological history in this class of models, emphasizing the simplest scenarios in which a dark matter candidate annihilates into hidden sector particles which then decay into visible matter through the vector, Higgs, or lepton portals. In each case, we find ample parameter space in which very heavy dark matter particles can provide an acceptable thermal relic abundance. We also discuss possible extensions of models featuring these dynamics.« less
PeV-scale dark matter as a thermal relic of a decoupled sector
Berlin, Asher; Hooper, Dan; Krnjaic, Gordan
2016-06-21
We consider a class of scenarios in which the dark matter is part of a heavy hidden sector that is thermally decoupled from the Standard Model in the early universe. The dark matter freezes-out by annihilating to a lighter, metastable state, whose subsequent abundance can naturally come to dominate the energy density of the universe. Moreover, when this state decays, it reheats the visible sector and dilutes all relic abundances, thereby allowing the dark matter to be orders of magnitude heavier than the weak scale. For concreteness, we consider a simple realization with a Dirac fermion dark matter candidate coupledmore » to a massive gauge boson that decays to the Standard Model through its kinetic mixing with hypercharge. Finally, we identify viable parameter space in which the dark matter can be as heavy as ~1-100 PeV without being overproduced in the early universe.« less
The 17 MeV anomaly in beryllium decays and U(1) portal to dark matter
NASA Astrophysics Data System (ADS)
Chen, Chian-Shu; Lin, Guey-Lin; Lin, Yen-Hsun; Xu, Fanrong
2017-11-01
The experiment of Krasznahorkay et al. observed the transition of a 8Be excited state to its ground state and accompanied by an emission of an e+e‑ pair with 17 MeV invariant mass. This 6.8σ anomaly can be fitted by a new light gauge boson. We consider the new particle as a U(1) gauge boson, Z‧, which plays as a portal linking dark sector and visible sector. In particular, we study the new U(1) gauge symmetry as a hidden or nonhidden group separately. The generic hidden U(1) model, referred to as dark Z model, is excluded by imposing various experimental constraints. On the other hand, a nonhidden Z‧ is allowed due to the additional interactions between Z‧ and Standard Model fermions. We also study the implication of the dark matter direct search on such a scenario. We found that the search for the DM-nucleon scattering cannot probe the parameter space that is allowed by 8Be-anomaly for the range of DM mass above 500 MeV. However, the DM-electron scattering for DM between 20 MeV and 50 MeV can test the underlying U(1) portal model using the future Si and Ge detectors with the 5e‑ threshold charges.
Lander, Bryn; Atkinson-Grosjean, Janet
2011-02-01
Innovation systems (IS) and science policy scholarship predominantly focus on linkages between universities and industry, and the commercial translation of academic discoveries. Overlooked in such analyses are important connections between universities and academic hospitals, and the non-commercial aspects of translational science. The two types of institutions tend to be collapsed into a single entity-'the university'-and relational flows are lost. Yet the distinctions and flows between the two are crucial elements of translational science and the biomedical innovation system. This paper explores what has been called the 'hidden research system' that connects hospitals, universities, and their resources, with the clinical and scientific actors who make the linkages possible. Then, using a novel conceptual model of translational science, we examine the individual interactions and dynamics involved in a particular example of the biomedical innovation system at work: the diagnosis of IRAK-4 deficiency, a rare immunological disorder, and the translational flows that result. Contra to conventional IS analyses, we are able to point to the strong role of public-sector institutions, and the weak role of the private-sector, in the translational processes described here. Our research was conducted within a Canadian network of scientists and clinician-scientists studying the pathogenomics of immunological disorders and innate immunity. Copyright © 2010 Elsevier Ltd. All rights reserved.
κ-deformed Dirac oscillator in an external magnetic field
NASA Astrophysics Data System (ADS)
Chargui, Y.; Dhahbi, A.; Cherif, B.
2018-04-01
We study the solutions of the (2 + 1)-dimensional κ-deformed Dirac oscillator in the presence of a constant transverse magnetic field. We demonstrate how the deformation parameter affects the energy eigenvalues of the system and the corresponding eigenfunctions. Our findings suggest that this system could be used to detect experimentally the effect of the deformation. We also show that the hidden supersymmetry of the non-deformed system reduces to a hidden pseudo-supersymmetry having the same algebraic structure as a result of the κ-deformation.
Ong, Lee-Ling S; Xinghua Zhang; Kundukad, Binu; Dauwels, Justin; Doyle, Patrick; Asada, H Harry
2016-08-01
An approach to automatically detect bacteria division with temporal models is presented. To understand how bacteria migrate and proliferate to form complex multicellular behaviours such as biofilms, it is desirable to track individual bacteria and detect cell division events. Unlike eukaryotic cells, prokaryotic cells such as bacteria lack distinctive features, causing bacteria division difficult to detect in a single image frame. Furthermore, bacteria may detach, migrate close to other bacteria and may orientate themselves at an angle to the horizontal plane. Our system trains a hidden conditional random field (HCRF) model from tracked and aligned bacteria division sequences. The HCRF model classifies a set of image frames as division or otherwise. The performance of our HCRF model is compared with a Hidden Markov Model (HMM). The results show that a HCRF classifier outperforms a HMM classifier. From 2D bright field microscopy data, it is a challenge to separate individual bacteria and associate observations to tracks. Automatic detection of sequences with bacteria division will improve tracking accuracy.
Precision Higgs Physics, Effective Field Theory, and Dark Matter
NASA Astrophysics Data System (ADS)
Henning, Brian Quinn
The recent discovery of the Higgs boson calls for detailed studies of its properties. As precision measurements are indirect probes of new physics, the appropriate theoretical framework is effective field theory. In the first part of this thesis, we present a practical three-step procedure of using the Standard Model effective field theory (SM EFT) to connect ultraviolet (UV) models of new physics with weak scale precision observables. With this procedure, one can interpret precision measurements as constraints on the UV model concerned. We give a detailed explanation for calculating the effective action up to one-loop order in a manifestly gauge covariant fashion. The covariant derivative expansion dramatically simplifies the process of matching a UV model with the SM EFT, and also makes available a universal formalism that is easy to use for a variety of UV models. A few general aspects of renormalization group running effects and choosing operator bases are discussed. Finally, we provide mapping results between the bosonic sector of the SM EFT and a complete set of precision electroweak and Higgs observables to which present and near future experiments are sensitive. With a detailed understanding of how to use the SM EFT, we then turn to applications and study in detail two well-motivated test cases. The first is singlet scalar field that enables the first-order electroweak phase transition for baryogenesis; the second example is due to scalar tops in the MSSM. We find both Higgs and electroweak measurements are sensitive probes of these cases. The second part of this thesis centers around dark matter, and consists of two studies. In the first, we examine the effects of relic dark matter annihilations on big bang nucleosynthesis (BBN). The magnitude of these effects scale simply with the dark matter mass and annihilation cross-section, which we derive. Estimates based on these scaling behaviors indicate that BBN severely constrains hadronic and radiative dark matter annihilation channels in the previously unconsidered dark matter mass region MeV <˜ m x <˜ 10 GeV. Interestingly, we find that BBN constraints on hadronic annihilation channels are competitive with similar bounds derived from the cosmic microwave background. Our second study of dark matter concerns a possible connection with supersymmetry and the keV scale. Various theoretical and experimental considerations motivate models with high scale supersymmetry breaking. While such models may be difficult to test in colliders, we propose looking for signatures at much lower energies. We show that a keV line in the X-ray spectrum of galaxy clusters (such as the recently disputed 3.5 keV observation) can have its origin in a universal string axion coupled to a hidden supersymmetry breaking sector. A linear combination of the string axion and an additional axion in the hidden sector remains light, obtaining a mass of order 10 keV through supersymmetry breaking dynamics. In order to explain the X-ray line, the scale of supersymmetry breaking must be about 1011-12 GeV. This motivates high scale supersymmetry as in pure gravity mediation or minimal split supersymmetry and is consistent with all current limits. Since the axion mass is controlled by a dynamical mass scale, this mass can be much higher during inflation, avoiding isocurvature (and domain wall) problems associated with high scale inflation. In an appendix E we present a mechanism for dilaton stabilization that additionally leads to O(1) modifications of the gaugino mass from anomaly mediation.
Hedge, L H; Dafforn, K A; Simpson, S L; Johnston, E L
2017-06-30
Infrastructure associated with coastal communities is likely to not only directly displace natural systems, but also leave environmental footprints' that stretch over multiple scales. Some coastal infrastructure will, there- fore, generate a hidden layer of habitat heterogeneity in sediment systems that is not immediately observable in classical impact assessment frameworks. We examine the hidden heterogeneity associated with one of the most ubiquitous coastal modifications; dense swing moorings fields. Using a model based geo-statistical framework we highlight the variation in sedimentology throughout mooring fields and reference locations. Moorings were correlated with patches of sediment with larger particle sizes, and associated metal(loid) concentrations in these patches were depressed. Our work highlights two important ideas i) mooring fields create a mosaic of habitat in which contamination decreases and grain sizes increase close to moorings, and ii) model- based frameworks provide an information rich, easy-to-interpret way to communicate complex analyses to stakeholders. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.
The Hidden Costs of Outdoor Education/Recreation Academic Training.
ERIC Educational Resources Information Center
Bisson, Christian
Academic training programs in the field of outdoor education and recreation have increased considerably in the past few decades, but their true costs are often hidden. A survey of 15 outdoor college programs in the United States and Canada examined special fees associated with outdoor courses. The cost of necessary personal equipment and clothing…
Taking Impressions of Hidden Cavity Walls
NASA Technical Reports Server (NTRS)
Burley, D.; Mayer, W.
1987-01-01
Lightweight, portable internal-molding device makes it possible to measure radii of, or examine contours of, passageways in hidden or complicated cavities. With device, measurements made in field, without returning assemblies to shop or laboratory for inspection. Molding head expands when compressed air applied. Inflatable tubes around head perform dual sealing and aligning function.
Hidden and antiferromagnetic order as a rank-5 superspin in URu2Si2
NASA Astrophysics Data System (ADS)
Rau, Jeffrey G.; Kee, Hae-Young
2012-06-01
We propose a candidate for the hidden order in URu2Si2: a rank-5 E type spin-density wave between uranium 5f crystal-field doublets Γ7(1) and Γ7(2), breaking time-reversal and lattice tetragonal symmetry in a manner consistent with recent torque measurements [Okazaki , ScienceSCIEAS0036-807510.1126/science.1197358 331, 439 (2011)]. We argue that coupling of this order parameter to magnetic probes can be hidden by crystal-field effects, while still having significant effects on transport, thermodynamics, and magnetic susceptibilities. In a simple tight-binding model for the heavy quasiparticles, we show the connection between the hidden order and antiferromagnetic phases arises since they form different components of this single rank-5 pseudospin vector. Using a phenomenological theory, we show that the experimental pressure-temperature phase diagram can be qualitatively reproduced by tuning terms which break pseudospin rotational symmetry. As a test of our proposal, we predict the presence of small magnetic moments in the basal plane oriented in the [110] direction ordered at the wave vector (0,0,1).
Cosmological abundance of the QCD axion coupled to hidden photons
NASA Astrophysics Data System (ADS)
Kitajima, Naoya; Sekiguchi, Toyokazu; Takahashi, Fuminobu
2018-06-01
We study the cosmological evolution of the QCD axion coupled to hidden photons. For a moderately strong coupling, the motion of the axion field leads to an explosive production of hidden photons by tachyonic instability. We use lattice simulations to evaluate the cosmological abundance of the QCD axion. In doing so, we incorporate the backreaction of the produced hidden photons on the axion dynamics, which becomes significant in the non-linear regime. We find that the axion abundance is suppressed by at most O (102) for the decay constant fa =1016GeV, compared to the case without the coupling. For a sufficiently large coupling, the motion of the QCD axion becomes strongly damped, and as a result, the axion abundance is enhanced. Our results show that the cosmological upper bound on the axion decay constant can be relaxed by a few hundred for a certain range of the coupling to hidden photons.
Multispectral THz-VIS passive imaging system for hidden threats visualization
NASA Astrophysics Data System (ADS)
Kowalski, Marcin; Palka, Norbert; Szustakowski, Mieczyslaw
2013-10-01
Terahertz imaging, is the latest entry into the crowded field of imaging technologies. Many applications are emerging for the relatively new technology. THz radiation penetrates deep into nonpolar and nonmetallic materials such as paper, plastic, clothes, wood, and ceramics that are usually opaque at optical wavelengths. The T-rays have large potential in the field of hidden objects detection because it is not harmful to humans. The main difficulty in the THz imaging systems is low image quality thus it is justified to combine THz images with the high-resolution images from a visible camera. An imaging system is usually composed of various subsystems. Many of the imaging systems use imaging devices working in various spectral ranges. Our goal is to build a system harmless to humans for screening and detection of hidden objects using a THz and VIS cameras.
Results from the Solar Hidden Photon Search (SHIPS)
DOE Office of Scientific and Technical Information (OSTI.GOV)
Schwarz, Matthias; Schneide, Magnus; Susol, Jaroslaw
We present the results of a search for transversely polarised hidden photons (HPs) with ∼ 3 eV energies emitted from the Sun. These hypothetical particles, known also as paraphotons or dark sector photons, are theoretically well motivated for example by string theory inspired extensions of the Standard Model. Solar HPs of sub-eV mass can convert into photons of the same energy (photon ↔ HP oscillations are similar to neutrino flavour oscillations). At SHIPS this would take place inside a long light-tight high-vacuum tube, which tracks the Sun. The generated photons would then be focused into a low-noise photomultiplier at the far end ofmore » the tube. Our analysis of 330 h of data (and 330 h of background characterisation) reveals no signal of photons from solar hidden photon conversion. We estimate the rate of newly generated photons due to this conversion to be smaller than 25 mHz/m{sup 2} at the 95% C.L . Using this and a recent model of solar HP emission, we set stringent constraints on χ, the coupling constant between HPs and photons, as a function of the HP mass.« less
Results from the Solar Hidden Photon Search (SHIPS)
DOE Office of Scientific and Technical Information (OSTI.GOV)
Schwarz, Matthias; Knabbe, Ernst-Axel; Lindner, Axel
We present the results of a search for transversely polarised hidden photons (HPs) with ∼3 eV energies emitted from the Sun. These hypothetical particles, known also as paraphotons or dark sector photons, are theoretically well motivated for example by string theory inspired extensions of the Standard Model. Solar HPs of sub-eV mass can convert into photons of the same energy (photon ↔ HP oscillations are similar to neutrino flavour oscillations). At SHIPS this would take place inside a long light-tight high-vacuum tube, which tracks the Sun. The generated photons would then be focused into a low-noise photomultiplier at the farmore » end of the tube. Our analysis of 330 h of data (and 330 h of background characterisation) reveals no signal of photons from solar hidden photon conversion. We estimate the rate of newly generated photons due to this conversion to be smaller than 25 mHz/m{sup 2} at the 95% C.L. Using this and a recent model of solar HP emission, we set stringent constraints on χ, the coupling constant between HPs and photons, as a function of the HP mass.« less
Cosmic selection rule for the glueball dark matter relic density
Soni, Amarjit; Xiao, Huangyu; Zhang, Yue
2017-10-16
Here, we point out a unique mechanism to produce the relic abundance for the glueball dark matter from a gauged SU(N) d hidden sector which is bridged to the standard model sector through heavy vectorlike quarks colored under gauge interactions from both sides. A necessary ingredient of our assumption is that the vectorlike quarks, produced either thermally or nonthermally, are abundant enough to dominate the universe for some time in the early universe. They later undergo dark color confinement and form unstable vectorlike-quarkonium states which annihilate decay and reheat the visible and dark sectors. The ratio of entropy dumped intomore » two sectors and the final energy budget in the dark glueballs is only determined by low energy parameters, including the intrinsic scale of the dark SU(N) d, Λ d, and number of dark colors, N d, but depend weakly on parameters in the ultraviolet such as the vectorlike quark mass or the initial condition. We call this a cosmic selection rule for the glueball dark matter relic density.« less
Cosmic selection rule for the glueball dark matter relic density
DOE Office of Scientific and Technical Information (OSTI.GOV)
Soni, Amarjit; Xiao, Huangyu; Zhang, Yue
Here, we point out a unique mechanism to produce the relic abundance for the glueball dark matter from a gauged SU(N) d hidden sector which is bridged to the standard model sector through heavy vectorlike quarks colored under gauge interactions from both sides. A necessary ingredient of our assumption is that the vectorlike quarks, produced either thermally or nonthermally, are abundant enough to dominate the universe for some time in the early universe. They later undergo dark color confinement and form unstable vectorlike-quarkonium states which annihilate decay and reheat the visible and dark sectors. The ratio of entropy dumped intomore » two sectors and the final energy budget in the dark glueballs is only determined by low energy parameters, including the intrinsic scale of the dark SU(N) d, Λ d, and number of dark colors, N d, but depend weakly on parameters in the ultraviolet such as the vectorlike quark mass or the initial condition. We call this a cosmic selection rule for the glueball dark matter relic density.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wester, W.; /Fermilab
2011-11-01
Physics beyond the Standard Model might include Weakly Interacting Slim Particles (WISPs) that address questions such as what is the nature of dark matter or even shed insight into the underlying nature of dark energy. WISPs are a general class of particles that include axions, axion-like particles, hidden sector photons, milli-charged particles, chameleons, etc. The GammeV (Gamma to milli-eV) experiment originated in 2007 in order to test a positive anomalous axion-like particle interpretation of the PVLAS experiment which was not evident in subsequent data. The experiment was also motivated as it was realized that the milli-eV scale appears naturally inmore » a see-saw between the electroweak and Planck scales, neutrino mass differences, the dark energy density, and the possible mass for certain dark matter candidates. GammeV was first to exclude both a scalar and pseudoscalar axion-like particle interpretation of the anomalous PVLAS result setting a limit of around 3.1 x 10{sup -7} GeV{sup -1} on the coupling to photons for low mass axion-like particles. It has also been found that the parameter space of a variety of other WISP candidates is both largely unexplored and is accessible by modest experiments employing lasers and possibly accelerator magnets. GammeV data has also been used to set limits on possible hidden sector photons. Further work by the GammeV team has focused on a reconfiguration of the apparatus to be sensitive to possible chameleon particles. Chameleons are scalar (or pseudoscalar) particles that couple to the stress energy tensor in a potential such that their properties depend on their environment. In particular, a chameleon acquires an effective mass which increases with local matter density, {rho}. For a certain class of such potentials, the chameleon field has properties that might explain dark energy. GammeV set the first limits on the coupling of chameleons to photons. A dedicated follow-up experiment, GammeV-CHASE, (CHameleon Afterglow SEarch), has also been performed and sets limits on both photon and some model dependent matter couplings as a function of an effective chameleon mass.« less
Hidden from view: coupled dark sector physics and small scales
NASA Astrophysics Data System (ADS)
Elahi, Pascal J.; Lewis, Geraint F.; Power, Chris; Carlesi, Edoardo; Knebe, Alexander
2015-09-01
We study cluster mass dark matter (DM) haloes, their progenitors and surroundings in a coupled dark matter-dark energy (DE) model and compare it to quintessence and Λ cold dark matter (ΛCDM) models with adiabatic zoom simulations. When comparing cosmologies with different expansions histories, growth functions and power spectra, care must be taken to identify unambiguous signatures of alternative cosmologies. Shared cosmological parameters, such as σ8, need not be the same for optimal fits to observational data. We choose to set our parameters to ΛCDM z = 0 values. We find that in coupled models, where DM decays into DE, haloes appear remarkably similar to ΛCDM haloes despite DM experiencing an additional frictional force. Density profiles are not systematically different and the subhalo populations have similar mass, spin, and spatial distributions, although (sub)haloes are less concentrated on average in coupled cosmologies. However, given the scatter in related observables (V_max,R_{V_max}), this difference is unlikely to distinguish between coupled and uncoupled DM. Observations of satellites of Milky Way and M31 indicate a significant subpopulation reside in a plane. Coupled models do produce planar arrangements of satellites of higher statistical significance than ΛCDM models; however, in all models these planes are dynamically unstable. In general, the non-linear dynamics within and near large haloes masks the effects of a coupled dark sector. The sole environmental signature we find is that small haloes residing in the outskirts are more deficient in baryons than their ΛCDM counterparts. The lack of a pronounced signal for a coupled dark sector strongly suggests that such a phenomena would be effectively hidden from view.
Realistic anomaly-mediated supersymmetry breaking
NASA Astrophysics Data System (ADS)
Chacko, Zacharia; Luty, Markus A.; Maksymyk, Ivan; Pontón, Eduardo
2000-03-01
We consider supersymmetry breaking communicated entirely by the superconformal anomaly in supergravity. This scenario is naturally realized if supersymmetry is broken in a hidden sector whose couplings to the observable sector are suppressed by more than powers of the Planck scale, as occurs if supersymmetry is broken in a parallel universe living in extra dimensions. This scenario is extremely predictive: soft supersymmetry breaking couplings are completely determined by anomalous dimensions in the effective theory at the weak scale. Gaugino and scalar masses are naturally of the same order, and flavor-changing neutral currents are automatically suppressed. The most glaring problem with this scenario is that slepton masses are negative in the minimal supersymmetric standard model. We point out that this problem can be simply solved by coupling extra Higgs doublets to the leptons. Lepton flavor-changing neutral currents can be naturally avoided by approximate symmetries. We also describe more speculative solutions involving compositeness near the weak scale. We then turn to electroweak symmetry breaking. Adding an explicit μ term gives a value for Bμ that is too large by a factor of ~ 100. We construct a realistic model in which the μ term arises from the vacuum expectation value of a singlet field, so all weak-scale masses are directly related to m3/2. We show that fully realistic electroweak symmetry breaking can occur in this model with moderate fine-tuning.
Role of band filling in tuning the high-field phases of URu 2 Si 2
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wartenbe, M. R.; Chen, K. -W.; Gallagher, A.
2017-08-28
We present a detailed study of the low temperature and high magnetic eld phases in the chemical substitution series URu 2Si 2-xPx using electrical transport and magnetization in pulsed magnetic elds up to 65T. Within the hidden order x-regime (0 < x ≲ 0.035) the eld induced ordering that was earlier seen for x = 0 is robust, even as the hidden order temperature is suppressed. Earlier work shows that for 0.035 ≲ x ≲ 0.26 there is a Kondo lattice with a no-ordered state that is replaced by antiferromagnetism for 0.26 ≲ x ≲ 0.5. We observe a simplimore » ed continuation of the eld induced order in the no-order x-regime and an enhancement of the field induced order upon the destruction of the antiferromagnetism with magnetic field. These results closely resemble what is seen for URu 2-xRhxSi 2 a, from which we infer that charge tuning dominantly controls the ground state of URu 2Si 2, regardless of whether s/p or d-electrons are replaced. Contraction of the unit cell volume may also play a role at large x. This provides guidance for determining the specific factors that lead to hidden order versus magnetism in this family of materials and constrains possible models for hidden order.« less
Emergence of higher order rotational symmetry in the hidden order phase of URu 2Si 2
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kanchanavatee, N.; Janoschek, M.; Huang, K.
2016-09-30
Electrical resistivity measurements were performed in this paper as functions of temperature, magnetic field, and angle θ between the magnetic field and the c-axis of a URu 2Si 2 single crystal. The resistivity exhibits a two-fold oscillation as a function of θ at high temperatures, which undergoes a 180°-phase shift (sign change) with decreasing temperature at around 35 K. The hidden order transition is manifested as a minimum in the magnetoresistance and amplitude of the two-fold oscillation. Interestingly, the resistivity also showed four-fold, six-fold, and eight-fold symmetries at the hidden order transition. These higher order symmetries were also detected atmore » low temperatures, which could be a sign of the formation of another pseudogap phase above the superconducting transition, consistent with recent evidence for a pseudogap from point-contact spectroscopy measurements and NMR. Measurements of the magnetisation of single crystalline URu 2Si 2 with the magnetic field applied parallel and perpendicular to the crystallographic c-axis revealed regions with linear temperature dependencies between the hidden order transition temperature and about 25 K. Finally, this T-linear behaviour of the magnetisation may be associated with the formation of a precursor phase or ‘pseudogap’ in the density of states in the vicinity of 30–35 K.« less
NMR in an electric field: A bulk probe of the hidden spin and orbital polarizations
NASA Astrophysics Data System (ADS)
Ramírez-Ruiz, Jorge; Boutin, Samuel; Garate, Ion
2017-12-01
Recent theoretical work has established the presence of hidden spin and orbital textures in nonmagnetic materials with inversion symmetry. Here, we propose that these textures can be detected by nuclear magnetic resonance (NMR) measurements carried out in the presence of an electric field. In crystals with hidden polarizations, a uniform electric field produces a staggered magnetic field that points to opposite directions at atomic sites related by spatial inversion. As a result, the NMR resonance peak corresponding to inversion partner nuclei is split into two peaks. The magnitude of the splitting is proportional to the electric field and depends on the orientation of the electric field with respect to the crystallographic axes and the external magnetic field. As a case study, we present a theory of electric-field-induced splitting of NMR peaks for 77Se,125Te, and 209Bi in Bi2Se3 and Bi2Te3 . In conducting samples with current densities of ≃106A/cm 2 , the splitting for Bi can reach 100 kHz , which is comparable to or larger than the intrinsic width of the NMR lines. In order to observe the effect experimentally, the peak splitting must also exceed the linewidth produced by the Oersted field. In Bi2Se3 , this requires narrow wires of radius ≲1 μ m . We also discuss other potentially more promising candidate materials, such as SrRuO3 and BaIr2Ge2 , whose crystal symmetry enables strategies to suppress the linewidth produced by the Oersted field.
Drazan, John F; Scott, John M; Hoke, Jahkeen I; Ledet, Eric H
2014-01-01
A hands-on learning module called "Science of the Slam" is created that taps into the passions and interests of an under-represented group in the fields of Science, Technology, Engineering and Mathematics (STEM). This is achieved by examining the use of the scientific method to quantify the biomechanics of basketball players who are good at performing the slam dunk. Students already have an intrinsic understanding of the biomechanics of basketball however this "hidden capital" has never translated into the underlying STEM concepts. The effectiveness of the program is rooted in the exploitation of "hidden capital" within the field of athletics to inform and enhance athletic performance. This translation of STEM concepts to athletic performance provides a context and a motivation for students to study the STEM fields who are traditionally disengaged from the classic engineering outreach programs. "Science of the Slam" has the potential to serve as a framework for other researchers to engage under-represented groups in novel ways by tapping into shared interests between the researcher and disadvantaged populations.
Inference for dynamics of continuous variables: the extended Plefka expansion with hidden nodes
NASA Astrophysics Data System (ADS)
Bravi, B.; Sollich, P.
2017-06-01
We consider the problem of a subnetwork of observed nodes embedded into a larger bulk of unknown (i.e. hidden) nodes, where the aim is to infer these hidden states given information about the subnetwork dynamics. The biochemical networks underlying many cellular and metabolic processes are important realizations of such a scenario as typically one is interested in reconstructing the time evolution of unobserved chemical concentrations starting from the experimentally more accessible ones. We present an application to this problem of a novel dynamical mean field approximation, the extended Plefka expansion, which is based on a path integral description of the stochastic dynamics. As a paradigmatic model we study the stochastic linear dynamics of continuous degrees of freedom interacting via random Gaussian couplings. The resulting joint distribution is known to be Gaussian and this allows us to fully characterize the posterior statistics of the hidden nodes. In particular the equal-time hidden-to-hidden variance—conditioned on observations—gives the expected error at each node when the hidden time courses are predicted based on the observations. We assess the accuracy of the extended Plefka expansion in predicting these single node variances as well as error correlations over time, focussing on the role of the system size and the number of observed nodes.
Lebed, A G
2011-08-19
We solve a long-standing problem about a theoretical description of the upper critical magnetic field, parallel to conducting layers and perpendicular to conducting chains, in a (TMTSF)(2)ClO(4) superconductor. In particular, we explain why the experimental upper critical field, H(c2)(b')≃6 T, is higher than both the quasiclassical upper critical field and the Clogston paramagnetic limit. We show that this property is due to the coexistence of the hidden reentrant and Larkin-Ovchinnikov-Fulde-Ferrell phases in a magnetic field in the form of three plane waves with nonzero momenta of the Cooper pairs. Our results are in good qualitative and quantitative agreement with the recent experimental measurements of H(c2)(b') and support a singlet d-wave-like scenario of superconductivity in (TMTSF)(2)ClO(4). © 2011 American Physical Society
R-Axion: A New LHC Physics Signature Involving Muon Pairs
DOE Office of Scientific and Technical Information (OSTI.GOV)
Goh, Hock-Seng; /UC, Berkeley /LBL, Berkeley; Ibe, Masahiro
2012-04-12
In a class of models with gauge mediated supersymmetry breaking, the existence of a light pseudo scalar particle, R-axion, with a mass in hundreds MeV range is predicted. The striking feature of such a light R-axion is that it mainly decays into a pair of muons and leaves a displaced vertex inside detectors once it is produced. In this talk, we show how we can search for the R-axion at the coming LHC experiments. The one main goal of the LHC experiments is discovering supersymmetry which has been anticipated for a long time to solve the hierarchy problem. Once themore » supersymmetric standard model (SSM) is confirmed experimentally, the next question is how the supersymmetry is broken and how the effects of symmetry breaking are mediated to the SSM sector. In most cases, such investigations on 'beyond the SSM physics' rely on arguments based on extrapolations of the observed supersymmetry mass parameters to higher energies. However, there is one class of models of supersymmetry breaking where we can get a direct glimpse of the structure of the hidden sector with the help of the R-symmetry. The R-symmetry plays an important role in rather generic models of spontaneous supersymmetry breaking. At the same time, however, it must be broken in some way in order for the gauginos in the SSM sector to have non-vanishing masses. One possibility of the gaugino mass generation is to consider models where the gaugino masses are generated as a result of the explicit breaking of the R-symmetries. Unfortunately, in those models, the R-symmetry leaves little trace for the collider experiments, since the mass of the R-axion is typically heavy and beyond the reach of the LHC experiments. In this talk, instead, we consider a class of models with gauge mediation where the R-symmetry in the hidden/messenger sectors is exact in the limit of the infinite reduced Planck scale, i.e. M{sub PL} {yields} {infinity}. In this case, the gaugino masses are generated only after the R-symmetry is broken spontaneously. We also assume that the R-symmetry is respected by the SSM sector as well as the origin of the higgsino mass {mu} and the Higgs mass mixing B{mu} at the classical level. We call this scenario, the minimal R-symmetry breaking scenario.« less
Hidden order and unconventional superconductivity in URu2Si2
NASA Astrophysics Data System (ADS)
Rau, Jeffrey; Kee, Hae-Young
2012-02-01
The nature of the so-called hidden order in URu2Si2 and the subsequent superconducting phase have remained a puzzle for over two decades. Motivated by evidence for rotational symmetry breaking seen in recent magnetic torque measurements [Okazaki et al. Science 331, 439 (2011)], we derive a simple tight-binding model consistent with experimental Fermi surface probes and ab-initio calculations. From this model we use mean-field theory to examine the variety of hidden orders allowed by existing experimental results, including the torque measurements. We then construct a phase diagram in temperature and pressure and discuss relevant experimental consequences.
Hidden Gratings in Holographic Liquid Crystal Polymer-Dispersed Liquid Crystal Films.
De Sio, Luciano; Lloyd, Pamela F; Tabiryan, Nelson V; Bunning, Timothy J
2018-04-18
Dynamic diffraction gratings that are hidden in the field-off state are fabricated utilizing a room-temperature photocurable liquid crystal (LC) monomer and nematic LC (NLC) using holographic photopolymerization techniques. These holographic LC polymer-dispersed LCs (HLCPDLCs) are hidden because of the refractive index matching between the LC polymer and the NLC regions in the as-formed state (no E-field applied). Application of a moderate E-field (5 V/μm) generates a refractive index mismatch because of the NLC reorientation (along the E-field) generating high-diffraction efficiency transmission gratings. These dynamic gratings are characterized by morphological, optical, and electrooptical techniques. They exhibit a morphology made of oriented LC polymer regions (containing residual NLC) alternating with a two-phase region of an NLC and LC polymer. Unlike classic holographic polymer-dispersed LC gratings formed with a nonmesogenic monomer, there is index matching between the as-formed alternating regions of the grating. These HLCPDLCs exhibit broad band and high diffraction efficiency (≈90%) at the Bragg angle, are transparent to white light across the visible range because of the refractive index matching, and exhibit fast response times (1 ms). The ability of HLCPDLCs not to consume electrical power in the off state opens new possibilities for the realization of energy-efficient switchable photonic devices.
Optical field encryption for secure transmission of data
NASA Astrophysics Data System (ADS)
Fraser, Colin B.; Harvey, Andrew R.
2004-12-01
The growing awareness of the vulnerability of information transmitted on communication systems within the government, military and commercial sectors, has stimulated a number of areas of research within the optical community to design optical hardware encryption systems providing inherent immunity to espionage techniques. This paper describes a hardware optical encryption technique that utilises off the shelf telecommunication equipment and negates the necessity for an independent key distribution system with respect to the data transmission system, as is common with alternative encryption system implementations. This method also lends itself easily to fiber optic or free space communication and is applicable within any optical waveband. The encryption-decryption of the optical signal is achieved through low coherence optical interferometry. This requires the instantaneous processing and analysis of the signal, optically, to retrieve the relevant optical phase information hidden in the transmitted optical noise. This technology allows an authorised user to transmit encrypted information at a high data rate securely, while maintaining opaqueness to an unauthorised observer that data transmission is occurring. As the instantaneous optical field properties of the signals present in the system are essential to the optical encryption - decryption process, the system is inherently protected against electronic recording and advances in computational decryption algorithms. For organisations wishing to protect sensitive data and levels of communication activity these are highly desirable features.
Exploiting the hidden symmetry of spinning black holes: conservation laws and numerical tests
NASA Astrophysics Data System (ADS)
Witzany, Vojtěch
2018-01-01
The Kerr black hole is stationary and axisymmetric, which leads to conservation of energy and azimuthal angular momentum along the orbits of free test particles in its vicinity, but also to conservation laws for the evolution of continuum matter fields. However, the Kerr space-time possesses an additional 'hidden symmetry', which exhibits itself in an unexpected conserved quantity along geodesics known as the Carter constant. We investigate the possibility of using this hidden symmetry to obtain conservation laws and other identities that could be used to test astrophysical simulations of the evolution of matter fields near spinning black holes. After deriving such identities, we set up a simple numerical toy model on which we demonstrate how they can detect the violations of evolution equations in a numerical simulation. Even though one of the expressions we derive is in the form of a conservation law, we end up recommending an equivalent but simpler expression that is not in the form of a conservation law for practical implementation.
A model for metastable magnetism in the hidden-order phase of URu2Si2
NASA Astrophysics Data System (ADS)
Boyer, Lance; Yakovenko, Victor M.
2018-01-01
We propose an explanation for the experiment by Schemm et al. (2015) where the polar Kerr effect (PKE), indicating time-reversal symmetry (TRS) breaking, was observed in the hidden-order (HO) phase of URu2Si2. The PKE signal on warmup was seen only if a training magnetic field was present on cool-down. Using a Ginzburg-Landau model for a complex order parameter, we show that the system can have a metastable ferromagnetic state producing the PKE, even if the HO ground state respects TRS. We predict that a strong reversed magnetic field should reset the PKE to zero.
Magneto-Radar Hidden Metal Detector
McEwan, Thomas E.
2005-07-05
A varying magnetic field excites slight vibrations in an object and a radar sensor detects the vibrations at a harmonic of the excitation frequency. The synergy of the magnetic excitation and radar detection provides increased detection range compared to conventional magnetic metal detectors. The radar rejects background clutter by responding only to reflecting objects that are vibrating at a harmonic excitation field, thereby significantly improving detection reliability. As an exemplary arrangement, an ultra-wideband micropower impulse radar (MIR) is capable of being employed to provide superior materials penetration while providing range information. The magneto-radar may be applied to pre-screening magnetic resonance imaging (MRI) patients, landmine detection and finding hidden treasures.
Central Compact Objects in Kes 79 and RCW 103 as `Hidden' Magnetars with Crustal Activity
NASA Astrophysics Data System (ADS)
Popov, S. B.; Kaurov, A. A.; Kaminker, A. D.
2015-05-01
We propose that observations of `hidden' magnetars in central compact objects can be used to probe crustal activity of neutron stars with large internal magnetic fields. Estimates based on calculations by Perna & Pons, Pons & Rea and Kaminker et al. suggest that central compact objects, which are proposed to be `hidden' magnetars, must demonstrate flux variations on the time scale of months-years. However, the most prominent candidate for the `hidden' magnetars - CXO J1852.6+0040 in Kes 79 - shows constant (within error bars) flux. This can be interpreted by lower variable crustal activity than in typical magnetars. Alternatively, CXO J1852.6+0040 can be in a high state of variable activity during the whole period of observations. Then we consider the source 1E161348 - 5055 in RCW103 as another candidate. Employing a simple 2D-modelling we argue that properties of the source can be explained by the crustal activity of the magnetar type. Thus, this object may be supplemented for the three known candidates for the `hidden' magnetars among central compact objects discussed in literature.
Hidden axion dark matter decaying through mixing with QCD axion and the 3.5 keV X-ray line
DOE Office of Scientific and Technical Information (OSTI.GOV)
Higaki, Tetsutaro; Kitajima, Naoya; Takahashi, Fuminobu, E-mail: thigaki@post.kek.jp, E-mail: kitajima@tuhep.phys.tohoku.ac.jp, E-mail: fumi@tuhep.phys.tohoku.ac.jp
2014-12-01
Hidden axions may be coupled to the standard model particles through a kinetic or mass mixing with QCD axion. We study a scenario in which a hidden axion constitutes a part of or the whole of dark matter and decays into photons through the mixing, explaining the 3.5 keV X-ray line signal. Interestingly, the required long lifetime of the hidden axion dark matter can be realized for the QCD axion decay constant at an intermediate scale, if the mixing is sufficiently small. In such a two component dark matter scenario, the primordial density perturbations of the hidden axion can bemore » highly non-Gaussian, leading to a possible dispersion in the X-ray line strength from various galaxy clusters and near-by galaxies. We also discuss how the parallel and orthogonal alignment of two axions affects their couplings to gauge fields. In particular, the QCD axion decay constant can be much larger than the actual Peccei-Quinn symmetry breaking.« less
NASA Astrophysics Data System (ADS)
Lieou, Charles K. C.; Elbanna, Ahmed E.; Carlson, Jean M.
2013-03-01
Sacrificial bonds and hidden length in structural molecules account for the greatly increased fracture toughness of biological materials compared to synthetic materials without such structural features, by providing a molecular-scale mechanism of energy dissipation. One example of occurrence of sacrificial bonds and hidden length is in the polymeric glue connection between collagen fibrils in animal bone. In this talk, we propose a simple kinetic model that describes the breakage of sacrificial bonds and the revelation of hidden length, based on Bell's theory. We postulate a master equation governing the rates of bond breakage and formation, at the mean-field level, allowing for the number of bonds and hidden lengths to take up non-integer values between successive, discrete bond-breakage events. This enables us to predict the mechanical behavior of a quasi-one-dimensional ensemble of polymers at different stretching rates. We find that both the rupture peak heights and maximum stretching distance increase with the stretching rate. In addition, our theory naturally permits the possibility of self-healing in such biological structures.
Kupersmith, Mark J; Anderson, Susan; Durbin, Mary; Kardon, Randy
2013-08-15
Scanning laser polarimetry (SLP) reveals abnormal retardance of birefringence in locations of the edematous peripapillary retinal nerve fiber layer (RNFL), which appear thickened by optical coherence tomography (OCT), in nonarteritic anterior ischemic optic neuropathy (NAION). We hypothesize initial sector SLP RNFL abnormalities will correlate with long-term regional visual field loss due to ischemic injury. We prospectively performed automated perimetry, SLP, and high definition OCT (HD-OCT) of the RNFL in 25 eyes with acute NAION. We grouped visual field threshold and RNFL values into Garway-Heath inferior/superior disc sectors and corresponding superior/inferior field regions. We compared sector SLP RNFL thickness with corresponding visual field values at presentation and at >3 months. At presentation, 12 eyes had superior sector SLP reduction, 11 of which had inferior field loss. Six eyes, all with superior field loss, had inferior sector SLP reduction. No eyes had reduced OCT-derived RNFL acutely. Eyes with abnormal field regions had corresponding SLP sectors thinner (P = 0.003) than for sectors with normal field regions. During the acute phase, the SLP-derived sector correlated with presentation (r = 0.59, P = 0.02) and with >3-month after presentation (r = 0.44, P = 0.02) corresponding superior and inferior field thresholds. Abnormal RNFL birefringence occurs in sectors corresponding to regional visual field loss during acute NAION when OCT-derived RNFL shows thickening. Since the visual field deficits show no significant recovery, SLP can be an early marker for axonal injury, which may be used to assess recovery potential at RNFL locations with respect to new treatments for acute NAION.
Bound states via Higgs exchanging and heavy resonant di-Higgs
NASA Astrophysics Data System (ADS)
Kang, Zhaofeng
2017-08-01
The existence of Higgs boson h predicted by the standard model (SM) was established and hunting for clues to new physics (NP) hidden in h has become the top priority in particle physics. In this paper we explore an intriguing phenomenon that prevails in NP associated with h, bound state (Bh, referring to the ground state only) of relatively heavy particles ϕ out of NP via interchanging h. This is well-motivated due to the intrinsic properties of h: It has zero spin and light mass, capable of mediating Yukawa interactions; moreover, it may be strongly coupled to ϕ in several important contexts, from addressing the naturalness problem by compositeness/supersymmetry (SUSY)/classical scale invariance to understanding neutrino mass origin radiatively and matter asymmetry by electroweak baryogensis. The new resonance Bh, being a neutral scalar boson, has important implications to the large hadron collider (LHC) di-Higgs search because it yields a clear resonant di-Higgs signature at the high mass region (≳ 1 TeV). In other words, searching for Bh offers a new avenue to probe the hidden sector with a Higgs-portal. For illustration in this paper we concentrate on two examples, the stop sector in SUSY and an inert Higgs doublet from a radiative neutrino model. In particular, h-mediation opens a new and wide window to probe the conventional stoponium and the current date begins to have sensitivity to stoponium around TeV.
NASA Astrophysics Data System (ADS)
Wang, Hai; Kumar, Asutosh; Cho, Minhyung; Wu, Junde
2018-04-01
Physical quantities are assumed to take real values, which stems from the fact that an usual measuring instrument that measures a physical observable always yields a real number. Here we consider the question of what would happen if physical observables are allowed to assume complex values. In this paper, we show that by allowing observables in the Bell inequality to take complex values, a classical physical theory can actually get the same upper bound of the Bell expression as quantum theory. Also, by extending the real field to the quaternionic field, we can puzzle out the GHZ problem using local hidden variable model. Furthermore, we try to build a new type of hidden-variable theory of a single qubit based on the result.
Subcommunities and Their Mutual Relationships in a Transaction Network
NASA Astrophysics Data System (ADS)
Iino, T.; Iyetomi, H.
We investigate a Japanese transaction network consisting ofabout 800 thousand firms (nodes) and four million business relations (links) with focus on its modular structure. Communities detected by maximizing modularity often are dominated by firms with common features or behaviors in the network, such as characterized by regions or industry sectors. However, it is well known that the modularity optimization approach has a resolution limit problem, that is, it fails in identifying fine communities buried in large communities. To unfold such hidden structures, we apply the community detection to each of subnetworks formed by isolating those communities from the whole body. Subcommunities thus identified are composed of firms with finer regions, more specified sectors or business affiliations. Also we introduce a new idea of reduced modularity matrix to measure the strength of relations between (sub)communities.
Higgs seesaw mechanism as a source for dark energy.
Krauss, Lawrence M; Dent, James B
2013-08-09
Motivated by the seesaw mechanism for neutrinos which naturally generates small neutrino masses, we explore how a small grand-unified-theory-scale mixing between the standard model Higgs boson and an otherwise massless hidden sector scalar can naturally generate a small mass and vacuum expectation value for the new scalar which produces a false vacuum energy density contribution comparable to that of the observed dark energy dominating the current expansion of the Universe. This provides a simple and natural mechanism for producing the correct scale for dark energy, even if it does not address the long-standing question of why much larger dark energy contributions are not produced from the visible sector. The new scalar produces no discernible signatures in existing terrestrial experiments so that one may have to rely on other cosmological tests of this idea.
Synchronization behaviors of coupled systems composed of hidden attractors
NASA Astrophysics Data System (ADS)
Zhang, Ge; Wu, Fuqiang; Wang, Chunni; Ma, Jun
2017-10-01
Based on a class of chaotic system composed of hidden attractors, in which the equilibrium points are described by a circular function, complete synchronization between two identical systems, pattern formation and synchronization of network is investigated, respectively. A statistical factor of synchronization is defined and calculated by using the mean field theory, the dependence of synchronization on bifurcation parameters discussed in numerical way. By setting a chain network, which local kinetic is described by hidden attractors, synchronization approach is investigated. It is found that the synchronization and pattern formation are dependent on the coupling intensity and also the selection of coupling variables. In the end, open problems are proposed for readers’ extensive guidance and investigation.
View-Dependent Streamline Deformation and Exploration
Tong, Xin; Edwards, John; Chen, Chun-Ming; Shen, Han-Wei; Johnson, Chris R.; Wong, Pak Chung
2016-01-01
Occlusion presents a major challenge in visualizing 3D flow and tensor fields using streamlines. Displaying too many streamlines creates a dense visualization filled with occluded structures, but displaying too few streams risks losing important features. We propose a new streamline exploration approach by visually manipulating the cluttered streamlines by pulling visible layers apart and revealing the hidden structures underneath. This paper presents a customized view-dependent deformation algorithm and an interactive visualization tool to minimize visual clutter in 3D vector and tensor fields. The algorithm is able to maintain the overall integrity of the fields and expose previously hidden structures. Our system supports both mouse and direct-touch interactions to manipulate the viewing perspectives and visualize the streamlines in depth. By using a lens metaphor of different shapes to select the transition zone of the targeted area interactively, the users can move their focus and examine the vector or tensor field freely. PMID:26600061
View-Dependent Streamline Deformation and Exploration
DOE Office of Scientific and Technical Information (OSTI.GOV)
Tong, Xin; Edwards, John; Chen, Chun-Ming
Occlusion presents a major challenge in visualizing 3D flow and tensor fields using streamlines. Displaying too many streamlines creates a dense visualization filled with occluded structures, but displaying too few streams risks losing important features. We propose a new streamline exploration approach by visually manipulating the cluttered streamlines by pulling visible layers apart and revealing the hidden structures underneath. This paper presents a customized view-dependent deformation algorithm and an interactive visualization tool to minimize visual cluttering for visualizing 3D vector and tensor fields. The algorithm is able to maintain the overall integrity of the fields and expose previously hidden structures.more » Our system supports both mouse and direct-touch interactions to manipulate the viewing perspectives and visualize the streamlines in depth. By using a lens metaphor of different shapes to select the transition zone of the targeted area interactively, the users can move their focus and examine the vector or tensor field freely.« less
View-Dependent Streamline Deformation and Exploration.
Tong, Xin; Edwards, John; Chen, Chun-Ming; Shen, Han-Wei; Johnson, Chris R; Wong, Pak Chung
2016-07-01
Occlusion presents a major challenge in visualizing 3D flow and tensor fields using streamlines. Displaying too many streamlines creates a dense visualization filled with occluded structures, but displaying too few streams risks losing important features. We propose a new streamline exploration approach by visually manipulating the cluttered streamlines by pulling visible layers apart and revealing the hidden structures underneath. This paper presents a customized view-dependent deformation algorithm and an interactive visualization tool to minimize visual clutter in 3D vector and tensor fields. The algorithm is able to maintain the overall integrity of the fields and expose previously hidden structures. Our system supports both mouse and direct-touch interactions to manipulate the viewing perspectives and visualize the streamlines in depth. By using a lens metaphor of different shapes to select the transition zone of the targeted area interactively, the users can move their focus and examine the vector or tensor field freely.
NASA Astrophysics Data System (ADS)
Anh, N. K.; Phonekeo, V.; My, V. C.; Duong, N. D.; Dat, P. T.
2014-02-01
In recent years, Vietnamese economy has been growing up rapidly and caused serious environmental quality plunging, especially in industrial and mining areas. It brings an enormous threat to a socially sustainable development and the health of human beings. Environmental quality assessment and protection are complex and dynamic processes, since it involves spatial information from multi-sector, multi-region and multi-field sources and needs complicated data processing. Therefore, an effective environmental protection information system is needed, in which considerable factors hidden in the complex relationships will become clear and visible. In this paper, the authors present the methodology which was used to generate environmental hazard maps which are applied to the integration of Analytic Hierarchy Process (AHP) and Geographical Information system (GIS). We demonstrate the results that were obtained from the study area in Dong Trieu district. This research study has contributed an overall perspective of environmental quality and identified the devastated areas where the administration urgently needs to establish an appropriate policy to improve and protect the environment.
NASA Astrophysics Data System (ADS)
Sun, Bao-Xi; Wan, Da-Ming; Zhao, Si-Yu
2018-05-01
The {{{D}}\\bar{{{D}}}}{{* }} interaction via a ρ or ω exchange is constructed within an extended hidden gauge symmetry approach, where the strange quark is replaced by the charm quark in the SU(3) flavor space. With this {{{D}}\\bar{{{D}}}}{{* }} interaction, a bound state slightly lower than the {{{D}}\\bar{{{D}}}}{{* }} threshold is generated dynamically in the isospin zero sector by solving the Bethe-Salpeter equation in the coupled-channel approximation, which might correspond to the X(3872) particle announced by many collaborations. This formulism is also used to study the {{{B}}\\bar{{{B}}}}{{* }} interaction, and a {{{B}}\\bar{{{B}}}}{{* }} bound state with isospin zero is generated dynamically, which has no counterpart listed in the review of the Particle Data Group. Furthermore, the one-pion exchange between the D meson and the {\\bar{{{D}}}}{{* }} is analyzed precisely, and we do not think the one-pion exchange potential need be considered when the Bethe-Salpeter equation is solved.
A Bell-type theorem without hidden variables
DOE Office of Scientific and Technical Information (OSTI.GOV)
Stapp, Henry P.
2003-09-12
It is shown that no theory that satisfies certain premises can exclude faster-than-light influences. The premises include neither the existence of hidden variables nor counterfactual definiteness, nor any premise that effectively entails the general existence of outcomes of unperformed local measurements. All the premises are compatible with Copenhagen philosophy and the principles and predictions of relativistic quantum field theory. The present proof is contrasted with an earlier one with the same objective.
Matrix Determination of Reflectance of Hidden Object via Indirect Photography
2012-03-01
the hidden object. This thesis provides an alternative method of processing the camera images by modeling the system as a set of transport and...Distribution Function ( BRDF ). Figure 1. Indirect photography with camera field of view dictated by point of illumination. 3 1.3 Research Focus In an...would need to be modeled using radiometric principles. A large amount of the improvement in this process was due to the use of a blind
The ``Folk Theorem'' on effective field theory: How does it fare in nuclear physics?
NASA Astrophysics Data System (ADS)
Rho, Mannque
2017-10-01
This is a brief history of what I consider as very important, some of which truly seminal, contributions made by young Korean nuclear theorists, mostly graduate students working on PhD thesis in 1990s and early 2000s, to nuclear effective field theory, nowadays heralded as the first-principle approach to nuclear physics. The theoretical framework employed is an effective field theory anchored on a single scale-invariant hidden local symmetric Lagrangian constructed in the spirit of Weinberg's "Folk Theorem" on effective field theory. The problems addressed are the high-precision calculations on the thermal np capture, the solar pp fusion process, the solar hep process — John Bahcall's challenge to nuclear theorists — and the quenching of g A in giant Gamow-Teller resonances and the whopping enhancement of first-forbidden beta transitions relevant in astrophysical processes. Extending adventurously the strategy to a wild uncharted domain in which a systematic implementation of the "theorem" is far from obvious, the same effective Lagrangian is applied to the structure of compact stars. A surprising, unexpected, result on the properties of massive stars, totally different from what has been obtained up to day in the literature, is predicted, such as the precocious onset of conformal sound velocity together with a hint for the possible emergence in dense matter of hidden symmetries such as scale symmetry and hidden local symmetry.
U.S. Military Technology Dependence: The Hidden Vulnerability to National Security
2016-06-10
complementary technologies among the services, decreasing the innovation to fielding timeline, and practice in degraded technology environments. 15. SUBJECT TERMS...technologies among the services, decreasing the innovation to fielding timeline, and practice in degraded technology environments. vi...29 SECTION 4: Fielding New Technology ................................................................... 32 Understanding the
The interplanetary and solar magnetic field sector structures, 1962 - 1968
NASA Technical Reports Server (NTRS)
Jones, D. E.
1972-01-01
The interplanetary magnetic field sector structure was observed from late 1962 through 1968. During this time it has been possible to study the manner in which the sector pattern and its relation to the photospheric magnetic field configuration changes from solar minimum to solar maximum. Observations were also made relating sector boundaries to specific regions on the solar disk. These and other observations related to the solar origin of the interplanetary field are briefly reviewed.
ERIC Educational Resources Information Center
Angeli, Charoula; Valanides, Nicos
2013-01-01
The present study investigated the problem-solving performance of 101 university students and their interactions with a computer modeling tool in order to solve a complex problem. Based on their performance on the hidden figures test, students were assigned to three groups of field-dependent (FD), field-mixed (FM), and field-independent (FI)…
The hidden costs of coastal hazards: Implications for risk assessment and mitigation
Kunreuther, H.; Platt, R.; Baruch, S.; Bernknopf, R.L.; Buckley, M.; Burkett, V.; Conrad, D.; Davidson, T.; Deutsch, K.; Geis, D.; Jannereth, M.; Knap, A.; Lane, H.; Ljung, G.; McCauley, M.; Mileti, D.; Miller, T.; Morrow, B.; Meyers, J.; Pielke, R.; Pratt, A.; Tripp, J.
2000-01-01
Society has limited hazard mitigation dollars to invest. Which actions will be most cost effective, considering the true range of impacts and costs incurred? In 1997, the H. John Heinz III Center for Science, Economics and the Environment began a two-year study with a panel of experts to help develop new strategies to identify and reduce the costs of weather-related hazards associated with rapidly increasing coastal development activities.The Hidden Costs of Coastal Hazards presents the panel's findings, offering the first in-depth study that considers the costs of coastal hazards to natural resources, social institutions, business, and the built environment. Using Hurricane Hugo, which struck South Carolina in 1989, as a case study, it provides for the first time information on the full range of economic costs caused by a major coastal hazard event. The book:describes and examines unreported, undocumented, and hidden costs such as losses due to business interruption, reduction in property values, interruption of social services, psychological trauma, damage to natural systems, and othersexamines the concepts of risk and vulnerability, and discusses conventional approaches to risk assessment and the emerging area of vulnerability assessmentrecommends a comprehensive framework for developing and implementing mitigation strategiesdocuments the human impact of Hurricane Hugo and provides insight from those who lived through it.The Hidden Costs of Coastal Hazards takes a structured approach to the problem of coastal hazards, offering a new framework for community-based hazard mitigation along with specific recommendations for implementation. Decisionmakers -- both policymakers and planners -- who are interested in coastal hazard issues will find the book a unique source of new information and insight, as will private-sector decisionmakers including lenders, investors, developers, and insurers of coastal property.
Koch-Straube, U
1982-01-01
The prevailing attitudes towards sexuality in old age are described in a rather phenomenological analysis: sexuality ends corresponding to the termination of reproductiveness; sexual needs in old age appear to be pathological; the elderly's sexual acts are disgusting. Empirical findings corroborate those conclusions. The situation is explained by societal circumstances, by the learning histories, and by the living conditions in old age. Examples of agreement with sexuality in old age demonstrate the often idle potentialities which are hidden in this sector of life.
Atlas of solar hidden photon emission
DOE Office of Scientific and Technical Information (OSTI.GOV)
Redondo, Javier, E-mail: redondo@mpp.mpg.de
2015-07-01
Hidden photons, gauge bosons of a U(1) symmetry of a hidden sector, can constitute the dark matter of the universe and a smoking gun for large volume compactifications of string theory. In the sub-eV mass range, a possible discovery experiment consists on searching the copious flux of these particles emitted from the Sun in a helioscope setup à la Sikivie. In this paper, we compute in great detail the flux of HPs from the Sun, a necessary ingredient for interpreting such experiments. We provide a detailed exposition of transverse photon-HP oscillations in inhomogenous media, with special focus on resonance oscillations,more » which play a leading role in many cases. The region of the Sun emitting HPs resonantly is a thin spherical shell for which we justify an averaged-emission formula and which implies a distinctive morphology of the angular distribution of HPs on Earth in many cases. Low mass HPs with energies in the visible and IR have resonances very close to the photosphere where the solar plasma is not fully ionised and requires building a detailed model of solar refraction and absorption. We present results for a broad range of HP masses (from 0–1 keV) and energies (from the IR to the X-ray range), the most complete atlas of solar HP emission to date.« less
Atlas of solar hidden photon emission
DOE Office of Scientific and Technical Information (OSTI.GOV)
Redondo, Javier; Max-Planck-Institut für Physik, Werner-Heisenberg-Institut,Föhringer Ring 6, 80805 München
2015-07-20
Hidden photons, gauge bosons of a U(1) symmetry of a hidden sector, can constitute the dark matter of the universe and a smoking gun for large volume compactifications of string theory. In the sub-eV mass range, a possible discovery experiment consists on searching the copious flux of these particles emitted from the Sun in a helioscope setup à la Sikivie. In this paper, we compute in great detail the flux of HPs from the Sun, a necessary ingredient for interpreting such experiments. We provide a detailed exposition of transverse photon-HP oscillations in inhomogenous media, with special focus on resonance oscillations,more » which play a leading role in many cases. The region of the Sun emitting HPs resonantly is a thin spherical shell for which we justify an averaged-emission formula and which implies a distinctive morphology of the angular distribution of HPs on Earth in many cases. Low mass HPs with energies in the visible and IR have resonances very close to the photosphere where the solar plasma is not fully ionised and requires building a detailed model of solar refraction and absorption. We present results for a broad range of HP masses (from 0–1 keV) and energies (from the IR to the X-ray range), the most complete atlas of solar HP emission to date.« less
Magnetic Correlations in URu2Si2 under Chemical and Hydrostatic Pressure
NASA Astrophysics Data System (ADS)
Williams, Travis; Aczel, Adam; Broholm, Collin; Buyers, William; Leao, Juscelino; Luke, Graeme; Rodriguez-Riviera, Jose; Stone, Matthew; Wilson, Murray; Yamani, Zahra
URu2Si2 has been an intense area of study for the last 30 years due to a mysterious hidden order phase that appears below T0 = 17.5 K. The hidden order phase has been shown to be extremely sensitive to perturbations, being destroyed quickly by the application of a magnetic field, hydrostatic or uniaxial pressure, and chemical doping. While attempting to understand the properties of URu2Si2, neutron scattering has found spin correlations that are intimately related to this hidden order phase and which are also suppressed with these perturbations. Here, I will outline some recent neutron scattering work to study these correlations in two exceptional cases where the hidden order phase is enhanced: hydrostatic pressure and chemical pressure using Fe- and Os-doping. In both of these cases, T0 increases before an antiferromagnetic phase emerges. By performing a careful analysis of the neutron data, we show that these two phases are much more related than had been previously appreciated. This implies that the hidden order is likely compatible with an antiferromagnetic ground state, placing constraints on the nature of the missing order parameter.
A coupled hidden Markov model for disease interactions
Sherlock, Chris; Xifara, Tatiana; Telfer, Sandra; Begon, Mike
2013-01-01
To investigate interactions between parasite species in a host, a population of field voles was studied longitudinally, with presence or absence of six different parasites measured repeatedly. Although trapping sessions were regular, a different set of voles was caught at each session, leading to incomplete profiles for all subjects. We use a discrete time hidden Markov model for each disease with transition probabilities dependent on covariates via a set of logistic regressions. For each disease the hidden states for each of the other diseases at a given time point form part of the covariate set for the Markov transition probabilities from that time point. This allows us to gauge the influence of each parasite species on the transition probabilities for each of the other parasite species. Inference is performed via a Gibbs sampler, which cycles through each of the diseases, first using an adaptive Metropolis–Hastings step to sample from the conditional posterior of the covariate parameters for that particular disease given the hidden states for all other diseases and then sampling from the hidden states for that disease given the parameters. We find evidence for interactions between several pairs of parasites and of an acquired immune response for two of the parasites. PMID:24223436
2016-12-12
During a tour for cast and crew members of the upcoming motion picture "Hidden Figures," Kennedy Space Center Director Bob Cabana poses with the group on the roof of the Vehicle Assembly Building. Among those participating are Kelvin Manning, associate center director; Meredith Lipsky, vice president of Field Marketing for 20th Century Fox; Ted Melfi, writer and director of “Hidden Figures;” Michelle Ryan, executive producer of the film; Pharrell Williams, musician and producer of “Hidden Figures;" Octavia Spencer, who portrays Dorothy Vaughan; Taraji P. Henson, who portrays Katherine Johnson in the film; Janet Petro, deputy center director; and Cabana. The movie is based on the book of the same title, by Margot Lee Shetterly. It chronicles the lives of Katherine Johnson, Dorothy Vaughan and Mary Jackson, three African-American women who worked for NASA as human "computers.” Their mathematical calculations were crucial to the success of Project Mercury missions including John Glenn’s orbital flight aboard Friendship 7 in 1962. The film is due in theaters in January 2017.
Higgs data does not rule out a sequential fourth generation with an extended scalar sector
NASA Astrophysics Data System (ADS)
Das, Dipankar; Kundu, Anirban; Saha, Ipsita
2018-01-01
Contrary to common perception, we show that the current Higgs data does not eliminate the possibility of a sequential fourth generation that get their masses through the same Higgs mechanism as the first three generations. The inability to fix the sign of the bottom-quark Yukawa coupling from the available data plays a crucial role in accommodating a chiral fourth generation which is consistent with the bounds on the Higgs signal strengths. We show that effects of such a fourth generation can remain completely hidden not only in the production of the Higgs boson through gluon fusion but also to its subsequent decay to γ γ and Z γ . This, however, is feasible only if the scalar sector of the standard model is extended. We also provide a practical example illustrating how our general prescription can be embedded in a realistic model.
Hidden treasures - 50 km points of interests
NASA Astrophysics Data System (ADS)
Lommi, Matias; Kortelainen, Jaana
2015-04-01
Tampere is third largest city in Finland and a regional centre. During 70's there occurred several communal mergers. Nowadays this local area has both strong and diversed identity - from wilderness and agricultural fields to high density city living. Outside the city center there are interesting geological points unknown for modern city settlers. There is even a local proverb, "Go abroad to Teisko!". That is the area the Hidden Treasures -student project is focused on. Our school Tammerkoski Upper Secondary School (or Gymnasium) has emphasis on visual arts. We are going to offer our art students scientific and artistic experiences and knowledge about the hidden treasures of Teisko area and involve the Teisko inhabitants into this project. Hidden treasures - Precambrian subduction zone and a volcanism belt with dense bed of gold (Au) and arsenic (As), operating goldmines and quarries of minerals and metamorphic slates. - North of subduction zone a homogenic precambrian magmastone area with quarries, products known as Kuru Grey. - Former ashores of post-glasial Lake Näsijärvi and it's sediments enabled the developing agriculture and sustained settlement. Nowadays these ashores have both scenery and biodiversity values. - Old cattle sheds and dairy buildings made of local granite stones related to cultural stonebuilding inheritance. - Local active community of Kapee, about 100 inhabitants. Students will discover information of these "hidden" phenomena, and rendering this information trough Enviromental Art Method. Final form of this project will be published in several artistic and informative geocaches. These caches are achieved by a GPS-based special Hidden Treasures Cycling Route and by a website guiding people to find these hidden points of interests.
Geologic and Seismologic Investigation
1988-12-01
Descriptions, Hidden and Buchanan Dams 4 1.6.1 Hidden Dam 4 1.6.2 Buchanan Dam 5 2 TECTONIC SETTING 2.1 General 7 2.2 Cretaceous-Cenozoic Tectonic ...Activity 7 2.2.1 Cretaceous-Paleogene 8 2.2.2 Neogene 9 2.2.3 Late Cenozoic Tectonic Model 9 3 REGIONAL GEOLOGY 3.1 General 11 3.2 Geologic Units 11...detected by the imagery analysis which indicates there has been no tectonic movement from about 100,000 to 400,000 years ago to the present. The field
Khan, L A
1996-01-01
Pakistan was the first developing country to be concerned about the population problem. The first family planning/population related efforts in Pakistan spawned from the nongovernmental sector in the form of the establishment of the Family Planning Association of Pakistan in 1953. The efforts of the association were then later acknowledged in the First Five-Year Public Sector Development Plan which made a lump sum provision of Rs. 5 million for population activities. The First Five-Year Plan (1955-60) recognized that measures should be taken to limit the size of the Pakistani family in order to reduce the incidence of malnutrition and overcrowding. There has never been an organized and consistent religious opposition to family planning in Pakistan. Islamic provisions in the constitution and diverse views of different groups of religious leaders do, however, pose an ongoing hidden political threat to the government which could be exploited through their street power in urban areas. The author notes that the governments in Pakistan will always be reluctant to aggressively promote family planning. Under these circumstances, the government must seek the cooperation of credible nongovernmental organizations which tend to operate through community-based volunteers who generally have more influence in persuading communities to accept a given point of view. Greater involvement of local community groups in a planned and meaningful way will broaden the base of program promoters and supporters across the country and will create a climate conducive to large-scale adoption of the small family norm as a way of life.
Diversity in a Hidden Community: Tardiagrades in Lichens.
ERIC Educational Resources Information Center
Shofner, Marcia; Vodopich, Darrell
1993-01-01
Describes an interesting field experiment examining the distribution and diversity of a single community using lichens and the animals living in them. Combining field experience and laboratory work reveals not only the biology of some unusual organisms, but also community ecology and diversity. (PR)
Random Assignment: Practical Considerations from Field Experiments.
ERIC Educational Resources Information Center
Dunford, Franklyn W.
1990-01-01
Seven qualitative issues associated with randomization that have the potential to weaken or destroy otherwise sound experimental designs are reviewed and illustrated via actual field experiments. Issue areas include ethics and legality, liability risks, manipulation of randomized outcomes, hidden bias, design intrusiveness, case flow, and…
NASA Astrophysics Data System (ADS)
Bonechi, L.; D'Alessandro, R.; Mori, N.; Viliani, L.
2015-02-01
Muon absorption radiography is an imaging technique based on the analysis of the attenuation of the cosmic-ray muon flux after traversing an object under examination. While this technique is now reaching maturity in the field of volcanology for the imaging of the innermost parts of the volcanic cones, its applicability to other fields of research has not yet been proved. In this paper we present a study concerning the application of the muon absorption radiography technique to the field of archaeology, and we propose a method for the search of underground cavities and structures hidden a few metres deep in the soil (patent [1]). An original geometric treatment of the reconstructed muon tracks, based on the comparison of the measured flux with a reference simulated flux, and the preliminary results of specific simulations are discussed in details.
The Hidden Factor in Early Field Experience: Teachers' Perception of the Quality of Life at Work.
ERIC Educational Resources Information Center
Divins, Barbara; And Others
This project identified work environment factors in eight schools where a teacher preparation program placed early field experience students and where the university students reported experiencing positive field placements. The purpose was to determine the impact of certain variables on teachers' perception of the quality of their own professional…
NASA Astrophysics Data System (ADS)
Turbiner, A. V.; Escobar-Ruiz, M. A.
2013-07-01
The quantum mechanics of two Coulomb charges on a plane (e1, m1) and (e2, m2) subject to a constant magnetic field B perpendicular to the plane is considered. Four integrals of motion are explicitly indicated. It is shown that for two physically important particular cases, namely that of two particles of equal Larmor frequencies, {e_c} \\propto \\frac{e_1}{m_1}-\\frac{e_2}{m_2}=0 (e.g. two electrons) and one of a neutral system (e.g. the electron-positron pair, hydrogen atom) at rest (the center-of-mass momentum is zero) some outstanding properties occur. They are the most visible in double polar coordinates in CMS (R, ϕ) and relative (ρ, φ) coordinate systems: (i) eigenfunctions are factorizable, all factors except one with the explicit ρ-dependence are found analytically, they have definite relative angular momentum, (ii) dynamics in the ρ-direction is the same for both systems, it corresponds to a funnel-type potential and it has hidden sl(2) algebra, at some discrete values of dimensionless magnetic fields b ⩽ 1, (iii) particular integral(s) occur, (iv) the hidden sl(2) algebra emerges in finite-dimensional representation, thus, the system becomes quasi-exactly-solvable and (v) a finite number of polynomial eigenfunctions in ρ appear. Nine families of eigenfunctions are presented explicitly.
Automated brain tumor segmentation using spatial accuracy-weighted hidden Markov Random Field.
Nie, Jingxin; Xue, Zhong; Liu, Tianming; Young, Geoffrey S; Setayesh, Kian; Guo, Lei; Wong, Stephen T C
2009-09-01
A variety of algorithms have been proposed for brain tumor segmentation from multi-channel sequences, however, most of them require isotropic or pseudo-isotropic resolution of the MR images. Although co-registration and interpolation of low-resolution sequences, such as T2-weighted images, onto the space of the high-resolution image, such as T1-weighted image, can be performed prior to the segmentation, the results are usually limited by partial volume effects due to interpolation of low-resolution images. To improve the quality of tumor segmentation in clinical applications where low-resolution sequences are commonly used together with high-resolution images, we propose the algorithm based on Spatial accuracy-weighted Hidden Markov random field and Expectation maximization (SHE) approach for both automated tumor and enhanced-tumor segmentation. SHE incorporates the spatial interpolation accuracy of low-resolution images into the optimization procedure of the Hidden Markov Random Field (HMRF) to segment tumor using multi-channel MR images with different resolutions, e.g., high-resolution T1-weighted and low-resolution T2-weighted images. In experiments, we evaluated this algorithm using a set of simulated multi-channel brain MR images with known ground-truth tissue segmentation and also applied it to a dataset of MR images obtained during clinical trials of brain tumor chemotherapy. The results show that more accurate tumor segmentation results can be obtained by comparing with conventional multi-channel segmentation algorithms.
Prospects for mirage mediation
NASA Astrophysics Data System (ADS)
Pierce, Aaron; Thaler, Jesse
2006-09-01
Mirage mediation reduces the fine-tuning in the minimal supersymmetric standard model by dynamically arranging a cancellation between anomaly-mediated and modulus-mediated supersymmetry breaking. We explore the conditions under which a mirage ``messenger scale'' is generated near the weak scale and the little hierarchy problem is solved. We do this by explicitly including the dynamics of the SUSY-breaking sector needed to cancel the cosmological constant. The most plausible scenario for generating a low mirage scale does not readily admit an extra-dimensional interpretation. We also review the possibilities for solving the μ/Bμ problem in such theories, a potential hidden source of fine-tuning.
Dark matter cosmic string in the gravitational field of a black hole
NASA Astrophysics Data System (ADS)
Nakonieczny, Łukasz; Nakonieczna, Anna; Rogatko, Marek
2018-03-01
We examined analytically and proposed a numerical model of an Abelian Higgs dark matter vortex in the spacetime of a stationary axisymmetric Kerr black hole. In analytical calculations the dark matter sector was modeled by an addition of a U(1)-gauge field coupled to the visible sector. The backreaction analysis revealed that the impact of the dark vortex presence is far more complicated than causing only a deficit angle. The vortex causes an ergosphere shift and the event horizon velocity is also influenced by its presence. These phenomena are more significant than in the case of a visible vortex sector. The area of the event horizon of a black hole is diminished and this decline is larger in comparison to the Kerr black hole with an Abelian Higgs vortex case. After analyzing the gravitational properties for the general setup, we focused on the subset of models that are motivated by particle physics. We retained the Abelian Higgs model as a description of the dark matter sector (this sector contained a heavy dark photon and an additional complex scalar) and added a real scalar representing the real component of the Higgs doublet in the unitary gauge, as well as an additional U(1)-gauge field representing an ordinary electromagnetic field. Moreover, we considered two coupling channels between the visible and dark sectors, which were the kinetic mixing between the gauge fields and a quartic coupling between the scalar fields. After solving the equations of motion for the matter fields numerically we analyzed properties of the cosmic string in the dark matter sector and its influence on the visible sector fields that are directly coupled to it. We found out that the presence of the cosmic string induced spatial variation in the vacuum expectation value of the Higgs field and a nonzero electromagnetic field around the black hole.
S-duality in SU(3) Yang-Mills theory with non-abelian unbroken gauge group
NASA Astrophysics Data System (ADS)
Schroers, B. J.; Bais, F. A.
1998-12-01
It is observed that the magnetic charges of classical monopole solutions in Yang-Mills-Higgs theory with non-abelian unbroken gauge group H are in one-to-one correspondence with coherent states of a dual or magnetic group H˜. In the spirit of the Goddard-Nuyts-Olive conjecture this observation is interpreted as evidence for a hidden magnetic symmetry of Yang-Mills theory. SU(3) Yang-Mills-Higgs theory with unbroken gauge group U(2) is studied in detail. The action of the magnetic group on semi-classical states is given explicitly. Investigations of dyonic excitations show that electric and magnetic symmetry are never manifest at the same time: Non-abelian magnetic charge obstructs the realisation of electric symmetry and vice-versa. On the basis of this fact the charge sectors in the theory are classified and their fusion rules are discussed. Non-abelian electric-magnetic duality is formulated as a map between charge sectors. Coherent states obey particularly simple fusion rules, and in the set of coherent states S-duality can be formulated as an SL(2, Z) mapping between sectors which leaves the fusion rules invariant.
NASA Astrophysics Data System (ADS)
Co, Raymond T.; Harigaya, Keisuke; Nomura, Yasunori
2017-03-01
We present a simple and natural dark sector model in which dark matter particles arise as composite states of hidden strong dynamics and their stability is ensured by accidental symmetries. The model has only a few free parameters. In particular, the gauge symmetry of the model forbids the masses of dark quarks, and the confinement scale of the dynamics provides the unique mass scale of the model. The gauge group contains an Abelian symmetry U (1 )D , which couples the dark and standard model sectors through kinetic mixing. This model, despite its simple structure, has rich and distinctive phenomenology. In the case where the dark pion becomes massive due to U (1 )D quantum corrections, direct and indirect detection experiments can probe thermal relic dark matter which is generically a mixture of the dark pion and the dark baryon, and the Large Hadron Collider can discover the U (1 )D gauge boson. Alternatively, if the dark pion stays light due to a specific U (1 )D charge assignment of the dark quarks, then the dark pion constitutes dark radiation. The signal of this radiation is highly correlated with that of dark baryons in dark matter direct detection.
Co, Raymond T; Harigaya, Keisuke; Nomura, Yasunori
2017-03-10
We present a simple and natural dark sector model in which dark matter particles arise as composite states of hidden strong dynamics and their stability is ensured by accidental symmetries. The model has only a few free parameters. In particular, the gauge symmetry of the model forbids the masses of dark quarks, and the confinement scale of the dynamics provides the unique mass scale of the model. The gauge group contains an Abelian symmetry U(1)_{D}, which couples the dark and standard model sectors through kinetic mixing. This model, despite its simple structure, has rich and distinctive phenomenology. In the case where the dark pion becomes massive due to U(1)_{D} quantum corrections, direct and indirect detection experiments can probe thermal relic dark matter which is generically a mixture of the dark pion and the dark baryon, and the Large Hadron Collider can discover the U(1)_{D} gauge boson. Alternatively, if the dark pion stays light due to a specific U(1)_{D} charge assignment of the dark quarks, then the dark pion constitutes dark radiation. The signal of this radiation is highly correlated with that of dark baryons in dark matter direct detection.
NASA Astrophysics Data System (ADS)
Rogotis, Savvas; Ioannidis, Dimosthenis; Tzovaras, Dimitrios; Likothanassis, Spiros
2015-04-01
The aim of this work is to present a novel approach for automatic recognition of suspicious activities in outdoor perimeter surveillance systems based on infrared video processing. Through the combination of size, speed and appearance based features, like the Center-Symmetric Local Binary Patterns, short-term actions are identified and serve as input, along with user location, for modeling target activities using the theory of Hidden Conditional Random Fields. HCRFs are used to directly link a set of observations to the most appropriate activity label and as such to discriminate high risk activities (e.g. trespassing) from zero risk activities (e.g loitering outside the perimeter). Experimental results demonstrate the effectiveness of our approach in identifying suspicious activities for video surveillance systems.
Interacting Electrons and Holes in Quasi-2D Quantum Dots in Strong Magnetic Fields
NASA Astrophysics Data System (ADS)
Hawrylak, P.; Sheng, W.; Cheng, S.-J.
2004-09-01
Theory of optical properties of interacting electrons and holes in quasi-2D quantum dots in strong magnetic fields is discussed. In two dimensions and the lowest Landau level, hidden symmetries control the interaction of the interacting system with light. By confining electrons and holes into quantum dots hidden symmetries can be removed and the excitation spectrum of electrons and excitons can be observed. We discuss a theory electronic and of excitonic quantum Hall droplets at a filling factorν=2. For an excitonic quantum Hall droplet the characteristic emission spectra are predicted to be related to the total spin of electron and hole configurations. For the electronic droplet the excitation spectrum of the droplet can be mapped out by measuring the emission for increasing number of electrons.
Texas A&M University in the JET Collaboration - Final Report
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fries, Rainer; Ko, Che-Ming
This final report summarizes the work done by PIs at Texas A&M University within the JET Topical Collaboration. The main focus of the group at Texas A&M has been the development and implementation of a hadronization model suitable to calculate hadronization of jet showers in heavy ion collisions event by event. The group successfully developed a hybrid model of parton recombination and remnant string fragmentation including recombination with thermal partons. A code realizing this model was developed and shared with other JET members. In addition, the group at Texas A&M worked on both open and hidden heavy flavor probes. Inmore » particular, they developed a description of heavy flavor hadronization based on recombination, and consistent with in-medium scattering rates of heavy quarks, and suggested the D s meson as a precise probe of the hadronization mechanism. Another noteworthy focus of their work was electromagnetic probes, in particular, dileptons and photons from interactions of jets with the medium. In the soft sector the group has made several contributions to modern topics, e.g. the splitting of elliptic flow between isospin partners and the role of the initial strong gluon fields.« less
Essays on environmental policies, corruption, and energy
NASA Astrophysics Data System (ADS)
Baksi, Soham
This thesis consists of four essays. The first essay looks at pollution taxation under capital mobility, and analyzes the role of pre-commitment by countries to their pollution tax rate. A polluting firm sells its product in two countries, and can locate and produce in a single country or in both countries. Due to the discrete-choice nature of the firm's location problem, the countries' welfare functions are discontinuous in their pollution tax rate. We show that when the countries cannot pre-commit to their pollution tax, the firm can still engender tax competition between them by strategically locating in both the countries. Moreover, pre-commitment pollution taxation may not be welfare improving for the countries, although it always makes the firm better off. The second essay studies the effect of liberalization on corruption. Corruptible inspectors enforce an environmental regulation on firms, and are monitored by an honest regulator. Liberalization not only increases the variety of goods and the marginal utility of accepting a bribe, but also puts pressure on the regulator to curb corruption. The interaction of these two effects can cause corruption to initially increase with liberalization, and then decrease beyond a threshold. Moreover, equilibrium corruption is lower when the regulator is able to pre-commit to her monitoring frequency. The third essay analyzes optimal labeling (information revelation) procedures for hidden attributes of credence goods. Consumers are heterogeneous in their preference for the hidden attribute, and producers can either self-label their products, or have them certified by a third party. The government can impose self or third-party labeling requirements on either the "green" or the "brown" producers. When corrupt producers can affix spurious labels, the government needs to monitor them. A mandatory self-labeling policy is shown to generally dominate mandatory third-party labeling. The fourth essay develops formulas for computing the economy-wide energy intensity decline rate by aggregating sectoral energy efficiency improvements, and sectoral shifts in economic activities. The formulas are used to (i) construct plausible scenarios for the global rate of energy intensity decline, and (ii) show the restraining role of the "electricity generation" sector on the energy intensity decline rate.
The Field Dependence-Independence Construct: Some, One, or None.
ERIC Educational Resources Information Center
Linn, Marcia C.; Kyllonen, Patrick
The field dependency/independency construct (FDI) was measured using tests of perception of the upright such as the Rod and Frame Test (RFT) and tests of cognitive restructuring such as the Hidden Figures Test (HFT); relationships between cognitive restructing and perception of the upright were investigated. High school seniors received 34 tests…
Ferromagnetic Objects Magnetovision Detection System.
Nowicki, Michał; Szewczyk, Roman
2013-12-02
This paper presents the application of a weak magnetic fields magnetovision scanning system for detection of dangerous ferromagnetic objects. A measurement system was developed and built to study the magnetic field vector distributions. The measurements of the Earth's field distortions caused by various ferromagnetic objects were carried out. The ability for passive detection of hidden or buried dangerous objects and the determination of their location was demonstrated.
Vien, Benjamin Steven; Rose, Louis Raymond Francis; Chiu, Wing Kong
2017-07-01
Reliable and quantitative non-destructive evaluation for small fatigue cracks, in particular those in hard-to-inspect locations, is a challenging problem. Guided waves are advantageous for structural health monitoring due to their slow geometrical decay of amplitude with propagating distance, which is ideal for rapid wide-area inspection. This paper presents a 3D laser vibrometry experimental and finite element analysis of the interaction between an edge-guided wave and a small through-thickness hidden edge crack on a racecourse shaped hole that occurs, in practice, as a fuel vent hole. A piezoelectric transducer is bonded on the straight edge of the hole to generate the incident wave. The excitation signal consists of a 5.5 cycle Hann-windowed tone burst of centre frequency 220 kHz, which is below the cut-off frequency for the first order Lamb wave modes (SH1). Two-dimensional fast Fourier transformation (2D FFT) is applied to the incident and scattered wave field along radial lines emanating from the crack mouth, so as to identify the wave modes and determine their angular variation and amplitude. It is shown experimentally and computationally that mid-plane symmetric edge waves can travel around the hole's edge to detect a hidden crack. Furthermore, the scattered wave field due to a small crack length, a , (compared to the wavelength λ of the incident wave) is shown to be equivalent to a point source consisting of a particular combination of body-force doublets. It is found that the amplitude of the scattered field increases quadratically as a function of a/λ , whereas the scattered wave pattern is independent of crack length for small cracks a < λ . This study of the forward scattering problem from a known crack size provides a useful guide for the inverse problem of hidden crack detection and sizing.
Poverty, economic growth, deprivation, and water: the cases of Cambodia and Vietnam.
Varis, Olli
2008-05-01
Poverty reduction decorates all development agendas, but the complexity of the poverty issue is too often hidden behind simplistic indicators and development goals. Here, a closer look is taken at the concepts of "deprivation" and "vulnerability" as outcomes of poverty. Deprivation leads typically to social exclusion and marginalization; such groups are particularly weak in getting themselves out of poverty by "self-help," and economic growth does not trickle down to these people. When looking at the connections between poverty reduction and economic growth, special emphasis should be put on the differences between modern and more traditional sectors: development of the modern sector should not marginalize and exclude those dependent on more traditional livelihoods. Two case studies--The Tonle Sap area, Cambodia, and the Mekong Delta, Vietnam--reveal that investment in education, empowerment of small-scale entrepreneurship and other means of microeconomic environment, along with good governance, infrastructure, and income distribution can ensure that economic growth includes the poorer echelons of society.
Atomic dark matter with hyperfine interactions
NASA Astrophysics Data System (ADS)
Boddy, Kimberly K.; Kaplinghat, Manoj; Kwa, Anna; Peter, Annika H. G.
2017-11-01
We consider dark matter as an analog of hydrogen in a secluded sector and study its astrophysical implications. The self interactions between dark matter particles include elastic scatterings as well as inelastic processes from hyperfine transitions. We show that for a dark hydrogen mass in the 10-100 GeV range and a dark fine-structure constant larger than 0.01, the self-interaction cross section has the right magnitude and velocity dependence to explain the low dark matter density cores seen in small galaxies while being consistent with all constraints from observations of galaxy clusters. Excitations to the hyperfine state and subsequent decays, however, may cause significant cooling losses and affect the evolution of low-mass halos. We also find minimum halo masses in the range of 103.5-107 M⊙, which are significantly larger than the typical predictions for weakly interacting dark matter models. This pattern of observables in structure formation is unique to this model, making it possible to determine the viability of hidden-sector hydrogen as a dark matter candidate.
NASA Technical Reports Server (NTRS)
Sieradski, L. M.; Giffin, C. E.; Nier, A. O. (Inventor)
1976-01-01
A mass spectrometer (MS) with unique magnetic pole pieces which provide a homogenous magnetic field across the gap of the MS magnetic sector as well as the magnetic field across an ion-type vacuum pump is disclosed. The pole pieces form the top and bottom sides of a housing. The housing is positioned so that portions of the pole pieces form part of the magnetic sector with the space between them defining the gap region of the magnetic sector, through which an ion beam passes. The pole pieces extend beyond the magnetic sector with the space between them being large enough to accommodate the electrical parts of an ion-type vacuum pump. The pole pieces which provide the magnetic field for the pump, together with the housing form the vacuum pump enclosure or housing.
Is the Magnetic Field in the Heliosheath Sector Region and in the Outer Heliosheath Laminar?
NASA Astrophysics Data System (ADS)
Opher, M.; Drake, J. F.; Swisdak, M. M.; Toth, G.
2010-12-01
All the current global models of the heliosphere are based on the assumption that the magnetic field in the outer heliosheath close to the heliopause is laminar. We argue that in the outer heliosheath the heliospheric magnetic field is not laminar but instead consists of nested magnetic islands. Recently, we proposed (Drake et al. 2009) that the annihilation of the ``sectored'' magnetic field within the heliosheath as it is compressed on its approach to the heliopause produces the anomalous cosmic rays (ACRs) and also energetic electrons. As a product of the annihilation of the sectored magnetic field, densly-packed magnetic islands are produced. These magnetic islands will be convected with the ambient flows as the sector boundary is carried to higher latitudes filling the outer heliosheath. We further argue that the magnetic islands will develop upstream (but still within the heliosheath) where collisionless reconnection is unfavorable -- large perturbations of the sector structure near the heliopause will cause compressions of the current sheet upstream, triggering reconnection. As a result, the magnetic field in the heliosheath sector region will be disordered well upstream of the heliopause. We present a 3D MHD simulation with unprecedent numerical resolution that captures the sector boundary. We show that due to the high pressure of the interstellar magnetic field the disordered sectored region fills a large portion of the northern part of the heliosphere with a smaller extension in the southern hemisphere. We test these ideas with observations of energetic electrons, which because of their high velocity are most sensitive to the structure of the magnetic field. We suggest that within our scenario we can explain two significant anomalies in the observations of energetic electrons in the outer heliosphere: the sudden decrease in the intensity of low energy electrons (0.02-1.5MeV) from the LECP instrument on Voyager 2 in 2008 (Decker 2010); and the dramatic differences in intensity trends between Galactic Cosmic Ray Electrons (3.8-59MeV) at Voyager 1 and 2 (McDonald 2010). We argue that these observations are a consequence of Voyager 2 leaving the sector region of disordered field in mid 2008 and crossing into a region of unipolar laminar field.
[Assessment of hidden curriculum components by medical students].
Ortega B, Javiera; Fasce H, Eduardo; Pérez V, Cristhian; Ibáñez G, Pilar; Márquez U, Carolina; Parra P, Paula
2014-11-01
Hidden curriculum refers to the unwritten, unofficial, and often unintended lessons, values, and perspectives that students learn at the university, which influences the acquisition of professional skills. To analyze the perception about the influence of the hidden curriculum in the education of medical students at the Universidad de Concepción, Chile. Qualitative investigation with case study approach. Seventeen graduated medical students were selected by probability sampling. A semi-structured interview was used to collect the information and a content analysis was applied. Forty seven percent of participants recognized having fulfilled their academic expectations. As favorable factors for academic achievement the students underlined clinical practice, access to patients and to clinical fields. As negative factors, they identified the lack of commitment, educational support and over-specialization of their mentors. The results show the strengths and weaknesses of the educational environment of undergraduated medical students. This information should be used to modify teaching environments.
NASA Astrophysics Data System (ADS)
Rogotis, Savvas; Palaskas, Christos; Ioannidis, Dimosthenis; Tzovaras, Dimitrios; Likothanassis, Spiros
2015-11-01
This work aims to present an extended framework for automatically recognizing suspicious activities in outdoor perimeter surveilling systems based on infrared video processing. By combining size-, speed-, and appearance-based features, like the local phase quantization and the histograms of oriented gradients, actions of small duration are recognized and used as input, along with spatial information, for modeling target activities using the theory of hidden conditional random fields (HCRFs). HCRFs are used to classify an observation sequence into the most appropriate activity label class, thus discriminating high-risk activities like trespassing from zero risk activities, such as loitering outside the perimeter. The effectiveness of this approach is demonstrated with experimental results in various scenarios that represent suspicious activities in perimeter surveillance systems.
Depth-resolved ballistic imaging in a low-depth-of-field optical Kerr gated imaging system
NASA Astrophysics Data System (ADS)
Zheng, Yipeng; Tan, Wenjiang; Si, Jinhai; Ren, YuHu; Xu, Shichao; Tong, Junyi; Hou, Xun
2016-09-01
We demonstrate depth-resolved imaging in a ballistic imaging system, in which a heterodyned femtosecond optical Kerr gate is introduced to extract useful imaging photons for detecting an object hidden in turbid media and a compound lens is proposed to ensure both the depth-resolved imaging capability and the long working distance. Two objects of about 15-μm widths hidden in a polystyrene-sphere suspension have been successfully imaged with approximately 600-μm depth resolution. Modulation-transfer-function curves with the object in and away from the object plane have also been measured to confirm the depth-resolved imaging capability of the low-depth-of-field (low-DOF) ballistic imaging system. This imaging approach shows potential for application in research of the internal structure of highly scattering fuel spray.
Depth-resolved ballistic imaging in a low-depth-of-field optical Kerr gated imaging system
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zheng, Yipeng; Tan, Wenjiang, E-mail: tanwenjiang@mail.xjtu.edu.cn; Si, Jinhai
2016-09-07
We demonstrate depth-resolved imaging in a ballistic imaging system, in which a heterodyned femtosecond optical Kerr gate is introduced to extract useful imaging photons for detecting an object hidden in turbid media and a compound lens is proposed to ensure both the depth-resolved imaging capability and the long working distance. Two objects of about 15-μm widths hidden in a polystyrene-sphere suspension have been successfully imaged with approximately 600-μm depth resolution. Modulation-transfer-function curves with the object in and away from the object plane have also been measured to confirm the depth-resolved imaging capability of the low-depth-of-field (low-DOF) ballistic imaging system. Thismore » imaging approach shows potential for application in research of the internal structure of highly scattering fuel spray.« less
Exploring non-holomorphic soft terms in the framework of gauge mediated supersymmetry breaking
NASA Astrophysics Data System (ADS)
Chattopadhyay, Utpal; Das, Debottam; Mukherjee, Samadrita
2018-01-01
It is known that in the absence of a gauge singlet field, a specific class of supersymmetry (SUSY) breaking non-holomorphic (NH) terms can be soft breaking in nature so that they may be considered along with the Minimal Supersymmetric Standard Model (MSSM) and beyond. There have been studies related to these terms in minimal supergravity based models. Consideration of an F-type SUSY breaking scenario in the hidden sector with two chiral superfields however showed Planck scale suppression of such terms. In an unbiased point of view for the sources of SUSY breaking, the NH terms in a phenomenological MSSM (pMSSM) type of analysis showed a possibility of a large SUSY contribution to muon g - 2, a reasonable amount of corrections to the Higgs boson mass and a drastic reduction of the electroweak fine-tuning for a higgsino dominated {\\tilde{χ}}_1^0 in some regions of parameter space. We first investigate here the effects of the NH terms in a low scale SUSY breaking scenario. In our analysis with minimal gauge mediated supersymmetry breaking (mGMSB) we probe how far the results can be compared with the previous pMSSM plus NH terms based study. We particularly analyze the Higgs, stop and the electroweakino sectors focusing on a higgsino dominated {\\tilde{χ}}_1^0 and {\\tilde{χ}}_1^{± } , a feature typically different from what appears in mGMSB. The effect of a limited degree of RG evolutions and vanishing of the trilinear coupling terms at the messenger scale can be overcome by choosing a non-minimal GMSB scenario, such as one with a matter-messenger interaction.
NASA Astrophysics Data System (ADS)
Getachew, Tibebu; Virtanen, Ilpo; Mursula, Kalevi
2017-04-01
The photospheric magnetic field is the source of the coronal and heliospheric magnetic fields (HMF), but their mutual correspondence is non-trivial and depends on the phase of the solar cycle. The photospheric field during the HMF sector crossings observed at 1 AU has been found to contain enhanced field intensities and definite polarity ordering, forming regions called Hale boundaries. Here we study the structure of the photospheric field during the HMF sector crossings during solar cycles 21-24, separately for the four phases of each solar cycle. We use a refined version of Svalgaard's list of major HMF sector crossings, mapped to the Sun using the solar wind speed observed at the Earth, and the daily level-3 magnetograms of the photospheric field measured at the Wilcox Solar Observatory in 1976-2014. We find that the structure of the photospheric field corresponding to the HMF sector crossings, and the existence and properties of the corresponding Hale bipolar regions varies significantly with solar cycle and with solar cycle phase. We find evidence for Hale boundaries in many, but not all ascending, maximum and declining phases of solar cycles but no minimum phase. The most clear Hale boundaries are found during the (+,-) HMF crossings in the northern hemisphere of odd cycles 21 and 23, but less systematically during the (+,-) crossings in the southern hemisphere of even cycles 22 and 24. We also find that the Hale structure of cycles 23 and 24 is more systematic than during cycles 21 and 22. This may be due to the weakening activity, which reduces the complexity of the photospheric field and clarifies the Hale pattern. The photospheric field distribution also depicts a larger area for the field of the northern hemisphere during the declining and minimum phases, in a good agreement with the bashful ballerina phenomenon. The HMF sector crossings observed at 1AU have only a partial correspondence to Hale boundaries in the photosphere, indicating that the two HMF sectors often originate from the opposite hemispheres across the equator. Our results also give evidence for hemispheric and polarity related differences in the photospheric field between the odd and even solar cycles.
Statistics of SU(5) D-brane models on a type II orientifold
NASA Astrophysics Data System (ADS)
Gmeiner, Florian; Stein, Maren
2006-06-01
We perform a statistical analysis of models with SU(5) and flipped SU(5) gauge group in a type II orientifold setup. We investigate the distribution and correlation of properties of these models, including the number of generations and the hidden sector gauge group. Compared to the recent analysis [F. Gmeiner, R. Blumenhagen, G. Honecker, D. Lüst, and T. Weigand, J. High Energy Phys.JHEPFG1029-8479 01 (2006) 004; F. Gmeiner, Fortschr. Phys.FPYKA60015-8208 54, 391 (2006).10.1088/1126-6708/2006/01/004] of models with a standard model-like gauge group, we find very similar results.
The Hidden Magnetic Field of the Young Neutron Star in Kesteven 79
NASA Astrophysics Data System (ADS)
Shabaltas, Natalia; Lai, Dong
2012-04-01
Recent observations of the central compact object in the Kesteven 79 supernova remnant show that this neutron star (NS) has a weak dipole magnetic field (a few × 1010 G) but an anomalously large (~64%) pulse fraction in its surface X-ray emission. We explore the idea that a substantial sub-surface magnetic field exists in the NS crust, which produces diffuse hot spots on the stellar surface due to anisotropic heat conduction, and gives rise to the observed X-ray pulsation. We develop a general-purpose method, termed "Temperature Template with Full Transport" (TTFT), that computes the synthetic pulse profile of surface X-ray emission from NSs with arbitrary magnetic field and surface temperature distributions, taking into account magnetic atmosphere opacities, beam pattern, vacuum polarization, and gravitational light bending. We show that a crustal toroidal magnetic field of order a few × 1014 G or higher, varying smoothly across the crust, can produce sufficiently distinct surface hot spots to generate the observed pulse fraction in the Kes 79 NS. This result suggests that substantial sub-surface magnetic fields, much stronger than the "visible" dipole fields, may be buried in the crusts of some young NSs, and such hidden magnetic fields can play an important role in their observational manifestations. The general TTFT tool we have developed can also be used for studying radiation from other magnetic NSs.
ERIC Educational Resources Information Center
Rahm, Jrène
2014-01-01
Informal science education is a broad field of research marked by fuzzy boundaries, tensions, and muddles among many disciplines, making for an unclear future trajectory (or trajectories) for the field of study. In this commentary, I unpack some of the hidden dimensions, tensions and challenges the five articles raise or point to implicitly in…
NASA Astrophysics Data System (ADS)
Yang, Shuangming; Deng, Bin; Wang, Jiang; Li, Huiyan; Liu, Chen; Fietkiewicz, Chris; Loparo, Kenneth A.
2017-01-01
Real-time estimation of dynamical characteristics of thalamocortical cells, such as dynamics of ion channels and membrane potentials, is useful and essential in the study of the thalamus in Parkinsonian state. However, measuring the dynamical properties of ion channels is extremely challenging experimentally and even impossible in clinical applications. This paper presents and evaluates a real-time estimation system for thalamocortical hidden properties. For the sake of efficiency, we use a field programmable gate array for strictly hardware-based computation and algorithm optimization. In the proposed system, the FPGA-based unscented Kalman filter is implemented into a conductance-based TC neuron model. Since the complexity of TC neuron model restrains its hardware implementation in parallel structure, a cost efficient model is proposed to reduce the resource cost while retaining the relevant ionic dynamics. Experimental results demonstrate the real-time capability to estimate thalamocortical hidden properties with high precision under both normal and Parkinsonian states. While it is applied to estimate the hidden properties of the thalamus and explore the mechanism of the Parkinsonian state, the proposed method can be useful in the dynamic clamp technique of the electrophysiological experiments, the neural control engineering and brain-machine interface studies.
Neural networks with local receptive fields and superlinear VC dimension.
Schmitt, Michael
2002-04-01
Local receptive field neurons comprise such well-known and widely used unit types as radial basis function (RBF) neurons and neurons with center-surround receptive field. We study the Vapnik-Chervonenkis (VC) dimension of feedforward neural networks with one hidden layer of these units. For several variants of local receptive field neurons, we show that the VC dimension of these networks is superlinear. In particular, we establish the bound Omega(W log k) for any reasonably sized network with W parameters and k hidden nodes. This bound is shown to hold for discrete center-surround receptive field neurons, which are physiologically relevant models of cells in the mammalian visual system, for neurons computing a difference of gaussians, which are popular in computational vision, and for standard RBF neurons, a major alternative to sigmoidal neurons in artificial neural networks. The result for RBF neural networks is of particular interest since it answers a question that has been open for several years. The results also give rise to lower bounds for networks with fixed input dimension. Regarding constants, all bounds are larger than those known thus far for similar architectures with sigmoidal neurons. The superlinear lower bounds contrast with linear upper bounds for single local receptive field neurons also derived here.
Do the Eyes Have It? Using Eye Tracking to Assess Students Cognitive Dimensions
ERIC Educational Resources Information Center
Nisiforou, Efi A.; Laghos, Andrew
2013-01-01
Field dependence/independence (FD/FI) is a significant dimension of cognitive styles. The paper presents results of a study that seeks to identify individuals' level of field independence during visual stimulus tasks processing. Specifically, it examined the relationship between the Hidden Figure Test (HFT) scores and the eye tracking metrics.…
Excitation of Nuclei and Atoms Trapping in Optical Fields of High Intensity
2006-11-01
the new relativistic wave equation for half- spin particle interacting with the electromagnetic field. The proposed equation is Lorentz and gauge ...CONTENTS Task 1. Gamma-ray laser with hidden inversion of nuclear state populations 3 Introduction 3 Recoil-accompanied nuclear...31 Task 2. Extended ensemble of monoenergetic atoms 33 Introduction 33 Results 37 Conclusion 66
Hidden Symmetries in String Theory
NASA Astrophysics Data System (ADS)
Chervonyi, Iurii
In this thesis we study hidden symmetries within the framework of string theory. Symmetries play a very important role in physics: they lead to drastic simplifications, which allow one to compute various physical quantities without relying on perturbative techniques. There are two kinds of hidden symmetries investigated in this work: the first type is associated with dynamics of quantum fields and the second type is related to integrability of strings on various backgrounds. Integrability is a remarkable property of some theories that allows one to determine all dynamical properties of the system using purely analytical methods. The goals of this thesis are twofold: extension of hidden symmetries known in General Relativity to stringy backgrounds in higher dimensions and construction of new integrable string theories. In the context of the first goal we study hidden symmetries of stringy backgrounds, with and without supersymmetry. For supersymmetric geometries produced by D-branes we identify the backgrounds with solvable equations for geodesics, which can potentially give rise to integrable string theories. Relaxing the requirement of supersymmetry, we also study charged black holes in higher dimensions and identify their hidden symmetries encoded in so-called Killing(-Yano) tensors. We construct the explicit form of the Killing(-Yano) tensors for the charged rotating black hole in arbitrary number of dimensions, study behavior of such tensors under string dualities, and use the analysis of hidden symmetries to explain why exact solutions for black rings (black holes with non-spherical event horizons) in more than five dimensions remain elusive. As a byproduct we identify the standard parameterization of AdSp x Sq backgrounds with elliptic coordinates on a flat base. The second goal of this work is construction of new integrable string theories by applying continuous deformations of known examples. We use the recent developments called (generalized) lambda-deformation to construct new integrable backgrounds depending on several continuous parameters and study analytical properties of the such deformations.
A Fast SVD-Hidden-nodes based Extreme Learning Machine for Large-Scale Data Analytics.
Deng, Wan-Yu; Bai, Zuo; Huang, Guang-Bin; Zheng, Qing-Hua
2016-05-01
Big dimensional data is a growing trend that is emerging in many real world contexts, extending from web mining, gene expression analysis, protein-protein interaction to high-frequency financial data. Nowadays, there is a growing consensus that the increasing dimensionality poses impeding effects on the performances of classifiers, which is termed as the "peaking phenomenon" in the field of machine intelligence. To address the issue, dimensionality reduction is commonly employed as a preprocessing step on the Big dimensional data before building the classifiers. In this paper, we propose an Extreme Learning Machine (ELM) approach for large-scale data analytic. In contrast to existing approaches, we embed hidden nodes that are designed using singular value decomposition (SVD) into the classical ELM. These SVD nodes in the hidden layer are shown to capture the underlying characteristics of the Big dimensional data well, exhibiting excellent generalization performances. The drawback of using SVD on the entire dataset, however, is the high computational complexity involved. To address this, a fast divide and conquer approximation scheme is introduced to maintain computational tractability on high volume data. The resultant algorithm proposed is labeled here as Fast Singular Value Decomposition-Hidden-nodes based Extreme Learning Machine or FSVD-H-ELM in short. In FSVD-H-ELM, instead of identifying the SVD hidden nodes directly from the entire dataset, SVD hidden nodes are derived from multiple random subsets of data sampled from the original dataset. Comprehensive experiments and comparisons are conducted to assess the FSVD-H-ELM against other state-of-the-art algorithms. The results obtained demonstrated the superior generalization performance and efficiency of the FSVD-H-ELM. Copyright © 2016 Elsevier Ltd. All rights reserved.
An overview of waste crime, its characteristics, and the vulnerability of the EU waste sector.
Baird, J; Curry, R; Cruz, P
2014-02-01
While waste is increasingly viewed as a resource to be globally traded, increased regulatory control on waste across Europe has created the conditions where waste crime now operates alongside a legitimate waste sector. Waste crime,is an environmental crime and a form of white-collar crime, which exploits the physical characteristics of waste, the complexity of the collection and downstream infrastructure, and the market opportunities for profit. This paper highlights some of the factors which make the waste sector vulnerable to waste crime. These factors include new legislation and its weak regulatory enforcement, the economics of waste treatment, where legal and safe treatment of waste can be more expensive than illegal operations, the complexity of the waste sector and the different actors who can have some involvement, directly or indirectly, in the movement of illegal wastes, and finally that waste can be hidden or disguised and creates an opportunity for illegal businesses to operate alongside legitimate waste operators. The study also considers waste crime from the perspective of particular waste streams that are often associated with illegal shipment or through illegal treatment and disposal. For each, the nature of the crime which occurs is shown to differ, but for each, vulnerabilities to waste crime are evident. The paper also describes some approaches which can be adopted by regulators and those involved in developing new legislation for identifying where opportunities for waste crime occurs and how to prevent it.
Implications of two-component dark matter induced by forbidden channels and thermal freeze-out
DOE Office of Scientific and Technical Information (OSTI.GOV)
Aoki, Mayumi; Toma, Takashi, E-mail: mayumi@hep.s.kanazawa-u.ac.jp, E-mail: takashi.toma@tum.de
2017-01-01
We consider a model of two-component dark matter based on a hidden U(1) {sub D} symmetry, in which relic densities of the dark matter are determined by forbidden channels and thermal freeze-out. The hidden U(1) {sub D} symmetry is spontaneously broken to a residual Z{sub 4} symmetry, and the lightest Z{sub 4} charged particle can be a dark matter candidate. Moreover, depending on the mass hierarchy in the dark sector, we have two-component dark matter. We show that the relic density of the lighter dark matter component can be determined by forbidden annihilation channels which require larger couplings compared tomore » the normal freeze-out mechanism. As a result, a large self-interaction of the lighter dark matter component can be induced, which may solve small scale problems of ΛCDM model. On the other hand, the heavier dark matter component is produced by normal freeze-out mechanism. We find that interesting implications emerge between the two dark matter components in this framework. We explore detectabilities of these dark matter particles and show some parameter space can be tested by the SHiP experiment.« less
Stress field forming of sector array transducers for vibro-acoustography.
Silva, Glauber T; Chen, Shigao; Frery, Alejandro C; Greenleaf, James F; Fatemi, Mostafa
2005-11-01
This paper presents a study of the stress field forming of sector array transducers for vibro-acoustography applications. The system point-spread function (PSF) is given in terms of the dynamic radiation stress exerted on a point target by a dual ultrasound beam with slightly different frequencies. The radiation stress is calculated by assuming that the resulting ultrasound beam is a plane wave. The stress is proportional to the product of the velocity potential of each incident ultrasound beam. The beamforming and stress field forming of sector array transducers are analyzed through linear acoustics. An expression for the velocity potential produced by sector array transducers is derived. The vibro-acoustography PSF is evaluated numerically. A comparison between the PSF of a sector array and a confocal transducers is presented. The compared characteristics of the PSF are sidelobe levels, transverse, and in-depth spatial resolution. Indeed, one motivation to study sector transducers is the fact the depth-of-field of these transducers should be smaller than that of same size confocal transducers. An experimental setup was used to validate the theoretical PSF of sector array transducers. Results show that the measured PSF is in good agreement with the theoretical predications. Vibro-acoustography images of a breast-phantom by both transducers are presented and discussed.
Alanazi, Adwan; Elleithy, Khaled
2016-01-01
Successful transmission of online multimedia streams in wireless multimedia sensor networks (WMSNs) is a big challenge due to their limited bandwidth and power resources. The existing WSN protocols are not completely appropriate for multimedia communication. The effectiveness of WMSNs varies, and it depends on the correct location of its sensor nodes in the field. Thus, maximizing the multimedia coverage is the most important issue in the delivery of multimedia contents. The nodes in WMSNs are either static or mobile. Thus, the node connections change continuously due to the mobility in wireless multimedia communication that causes an additional energy consumption, and synchronization loss between neighboring nodes. In this paper, we introduce an Optimized Hidden Node Detection (OHND) paradigm. The OHND consists of three phases: hidden node detection, message exchange, and location detection. These three phases aim to maximize the multimedia node coverage, and improve energy efficiency, hidden node detection capacity, and packet delivery ratio. OHND helps multimedia sensor nodes to compute the directional coverage. Furthermore, an OHND is used to maintain a continuous node– continuous neighbor discovery process in order to handle the mobility of the nodes. We implement our proposed algorithms by using a network simulator (NS2). The simulation results demonstrate that nodes are capable of maintaining direct coverage and detecting hidden nodes in order to maximize coverage and multimedia node mobility. To evaluate the performance of our proposed algorithms, we compared our results with other known approaches. PMID:27618048
Alanazi, Adwan; Elleithy, Khaled
2016-09-07
Successful transmission of online multimedia streams in wireless multimedia sensor networks (WMSNs) is a big challenge due to their limited bandwidth and power resources. The existing WSN protocols are not completely appropriate for multimedia communication. The effectiveness of WMSNs varies, and it depends on the correct location of its sensor nodes in the field. Thus, maximizing the multimedia coverage is the most important issue in the delivery of multimedia contents. The nodes in WMSNs are either static or mobile. Thus, the node connections change continuously due to the mobility in wireless multimedia communication that causes an additional energy consumption, and synchronization loss between neighboring nodes. In this paper, we introduce an Optimized Hidden Node Detection (OHND) paradigm. The OHND consists of three phases: hidden node detection, message exchange, and location detection. These three phases aim to maximize the multimedia node coverage, and improve energy efficiency, hidden node detection capacity, and packet delivery ratio. OHND helps multimedia sensor nodes to compute the directional coverage. Furthermore, an OHND is used to maintain a continuous node- continuous neighbor discovery process in order to handle the mobility of the nodes. We implement our proposed algorithms by using a network simulator (NS2). The simulation results demonstrate that nodes are capable of maintaining direct coverage and detecting hidden nodes in order to maximize coverage and multimedia node mobility. To evaluate the performance of our proposed algorithms, we compared our results with other known approaches.
NASA Astrophysics Data System (ADS)
Aiello, Andrea; Ornigotti, Marco
2014-09-01
We address the question of whether there exists a hidden relationship between the near-field distribution generated by an oscillating electric dipole and the so-called cross-polarization of a collimated beam of light. We find that the answer is affirmative by showing that the complex field distributions occurring in both cases have a common physical origin: the requirement that the electromagnetic fields must be transverse.
Fermi surface in the hidden-order state of URu2Si2 under intense pulsed magnetic fields up to 81 T
NASA Astrophysics Data System (ADS)
Scheerer, G. W.; Knafo, W.; Aoki, D.; Nardone, M.; Zitouni, A.; Béard, J.; Billette, J.; Barata, J.; Jaudet, C.; Suleiman, M.; Frings, P.; Drigo, L.; Audouard, A.; Matsuda, T. D.; Pourret, A.; Knebel, G.; Flouquet, J.
2014-04-01
We present measurements of the resistivity ρx ,x of URu2Si2 high-quality single crystals in pulsed high magnetic fields up to 81 T at a temperature of 1.4 K and up to 60 T at temperatures down to 100 mK. For a field H applied along the magnetic easy axis c, a strong sample dependence of the low-temperature resistivity in the hidden-order phase is attributed to a high carrier mobility. The interplay between the magnetic and orbital properties is emphasized by the angle dependence of the phase diagram, where magnetic transition fields and crossover fields related to the Fermi surface properties follow a 1/cosθ law, θ being the angle between H and c. For H ∥c, a crossover defined at a kink of ρx ,x, as initially reported in [Shishido, Phys. Rev. Lett. 102, 156403 (2009), 10.1103/PhysRevLett.102.156403], is found to be strongly sample dependent: its characteristic field μ0H* varies from ≃20 T in our best sample with a residual resistivity ratio RRR = ρx ,x(300K)/ ρx ,x(2K) of 225 to ≃25 T in a sample with a RRR of 90. A second crossover is defined at the maximum of ρx ,x at the sample-independent low-temperature (LT) characteristic field μ0Hρ,maxLT≃30 T. Fourier analyses of Shubnikov-de Haas oscillations show that Hρ,maxLT coincides with a sudden modification of the Fermi surface, while H* lies in a regime where the Fermi surface is smoothly modified. For H ∥a, (i) no phase transition is observed at low temperature and the system remains in the hidden-order phase up to 81 T, (ii) quantum oscillations surviving up to 7 K are related to a new orbit observed at the frequency Fλ≃1350 T and associated with a low effective mass mλ*=(1±0.5)m0, where m0 is the free electron mass, and (iii) no Fermi surface modification occurs up to 81 T.
Field theories and fluids for an interacting dark sector
NASA Astrophysics Data System (ADS)
Carrillo González, Mariana; Trodden, Mark
2018-02-01
We consider the relationship between fluid models of an interacting dark sector and the field theoretical models that underlie such descriptions. This question is particularly important in light of suggestions that such interactions may help alleviate a number of current tensions between different cosmological datasets. We construct consistent field theory models for an interacting dark sector that behave exactly like the coupled fluid ones, even at the level of linear perturbations, and can be trusted deep in the nonlinear regime. As a specific example, we focus on the case of a Dirac, Born-Infeld (DBI) field conformally coupled to a quintessence field. We show that the fluid linear regime breaks before the field gradients become large; this means that the field theory is valid inside a large region of the fluid nonlinear regime.
ERIC Educational Resources Information Center
Rittschof, Kent A.
2010-01-01
Field dependence-independence (FDI) has long been conceptualized and discussed as a cognitive style relevant to numerous educational approaches and outcomes. However, the FDI construct is most often measured as a cognitive ability, as opposed to a style, using instruments such as the Group-Embedded Figures test (GEFT) or the Hidden Figures Test…
NASA Astrophysics Data System (ADS)
Rout, Diptiranjan; Chakrabarty, D.; Sarkhel, S.; Sekar, R.; Fejer, B. G.; Reeves, G. D.; Kulkarni, Atul S.; Aponte, Nestor; Sulzer, Mike; Mathews, John D.; Kerr, Robert B.; Noto, John
2018-05-01
On 13 April 2013, the ACE spacecraft detected arrival of an interplanetary shock at 2250 UT, which is followed by the passage of the sheath region of an interplanetary coronal mass ejection (ICME) for a prolonged (18-hr) period. The polarity of interplanetary magnetic field Bz was northward inside the magnetic cloud region of the ICME. The ring current (SYM-H) index did not go below -7 nT during this event suggesting the absence of a typical geomagnetic storm. The responses of the global ionospheric electric field associated with the passage of the ICME sheath region have been investigated using incoherent scatter radar measurements of Jicamarca and Arecibo (postmidnight sector) along with the variations of equatorial electrojet strength over India (day sector). It is found that westward and eastward prompt penetration (PP) electric fields affected ionosphere over Jicamarca/Arecibo and Indian sectors, respectively, during 0545-0800 UT. The polarities of the PP electric field perturbations over the day/night sectors are consistent with model predictions. In fact, DP2-type electric field perturbations with ˜40-min periodicity are found to affect the ionosphere over both the sectors for about 2.25 hr during the passage of the ICME sheath region. This result shows that SYM-H index may not capture the full geoeffectivenss of the ICME sheath-driven storms and suggests that the PP electric field perturbations should be evaluated for geoeffectiveness of ICME when the polarity of interplanetary magnetic field Bz is northward inside the magnetic cloud region of the ICME.
Under-reported data analysis with INAR-hidden Markov chains.
Fernández-Fontelo, Amanda; Cabaña, Alejandra; Puig, Pedro; Moriña, David
2016-11-20
In this work, we deal with correlated under-reported data through INAR(1)-hidden Markov chain models. These models are very flexible and can be identified through its autocorrelation function, which has a very simple form. A naïve method of parameter estimation is proposed, jointly with the maximum likelihood method based on a revised version of the forward algorithm. The most-probable unobserved time series is reconstructed by means of the Viterbi algorithm. Several examples of application in the field of public health are discussed illustrating the utility of the models. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Supersymmetry models and phenomenology
NASA Astrophysics Data System (ADS)
Carpenter, Linda M.
We present several models of supersymmetry breaking and explore their phenomenological consequences. First, we build models utilizing the supersymmetry breaking formalism of anomaly mediation. Our first model consists of the minimal supersymmetric standard model plus a singlet, anomaly-mediated soft masses and a Dirac mass which marries the bino to the singlet. The Dirac mass does not affect the so-called "UV insensitivity" of the other soft parameters to running or supersymmetric thresholds and thus flavor physics at intermediate scales would not reintroduce the flavor problem. The Dirac bino is integrated out at a few TeV and produces finite and positive contributions to all hyper-charged scalars at one loop thus producing positive squared slepton masses. Our second model approaches anomaly mediation from the point of view of the mu problem. We present a minimal method for generating a mu term while still generating a viable spectrum. We introduce a new operator involving a hidden sector U(1) gauge field which is then canceled against a Giudice-Masiero-like mu term. No new flavor violating operators are allowed. This procedure produces viable electroweak symmetry breaking in the Higgs sector. Only a single pair of new vector-like messenger fields is needed to correct the slepton masses by deflecting them from their anomaly mediated trajectories. Finally we attempt to solve the Higgs mass tuning problem in the MSSM; both electroweak precision measurements and simple supersymmetric extensions of the standard model prefer the mass of the Higgs boson to be around the Z mass. However, LEP II rules out a standard model-like Higgs lighter than 114.4 GeV. We show that supersymmetric models with R parity violation have a large range of parameter space in which the Higgs effectively decays to six jets (for Baryon number violation) or four jets plus taus and/or missing energy (for Lepton number violation). These decays are much more weakly constrained by current LEP analyses and could be probed by new exclusive channel analyses as well as a combined "model independent" Higgs search analysis by all experiments.
Optimizing Experimental Designs: Finding Hidden Treasure.
USDA-ARS?s Scientific Manuscript database
Classical experimental design theory, the predominant treatment in most textbooks, promotes the use of blocking designs for control of spatial variability in field studies and other situations in which there is significant variation among heterogeneity among experimental units. Many blocking design...
Hidden edge Dirac point and robust quantum edge transport in InAs/GaSb quantum wells
NASA Astrophysics Data System (ADS)
Li, Chang-An; Zhang, Song-Bo; Shen, Shun-Qing
2018-01-01
The robustness of quantum edge transport in InAs/GaSb quantum wells in the presence of magnetic fields raises an issue on the fate of topological phases of matter under time-reversal symmetry breaking. A peculiar band structure evolution in InAs/GaSb quantum wells is revealed: the electron subbands cross the heavy hole subbands but anticross the light hole subbands. The topologically protected band crossing point (Dirac point) of the helical edge states is pulled to be close to and even buried in the bulk valence bands when the system is in a deeply inverted regime, which is attributed to the existence of the light hole subbands. A sizable Zeeman energy gap verified by the effective g factors of edge states opens at the Dirac point by an in-plane or perpendicular magnetic field; however, it can also be hidden in the bulk valance bands. This provides a plausible explanation for the recent observation on the robustness of quantum edge transport in InAs/GaSb quantum wells subjected to strong magnetic fields.
The Formation of Magnetic Depletions and Flux Annihilation Due to Reconnection in the Heliosheath
DOE Office of Scientific and Technical Information (OSTI.GOV)
Drake, J. F.; Swisdak, M.; Opher, M.
The misalignment of the solar rotation axis and the magnetic axis of the Sun produces a periodic reversal of the Parker spiral magnetic field and the sectored solar wind. The compression of the sectors is expected to lead to reconnection in the heliosheath (HS). We present particle-in-cell simulations of the sectored HS that reflect the plasma environment along the Voyager 1 and 2 trajectories, specifically including unequal positive and negative azimuthal magnetic flux as seen in the Voyager data. Reconnection proceeds on individual current sheets until islands on adjacent current layers merge. At late time, bands of the dominant fluxmore » survive, separated by bands of deep magnetic field depletion. The ambient plasma pressure supports the strong magnetic pressure variation so that pressure is anticorrelated with magnetic field strength. There is little variation in the magnetic field direction across the boundaries of the magnetic depressions. At irregular intervals within the magnetic depressions are long-lived pairs of magnetic islands where the magnetic field direction reverses so that spacecraft data would reveal sharp magnetic field depressions with only occasional crossings with jumps in magnetic field direction. This is typical of the magnetic field data from the Voyager spacecraft. Voyager 2 data reveal that fluctuations in the density and magnetic field strength are anticorrelated in the sector zone, as expected from reconnection, but not in unipolar regions. The consequence of the annihilation of subdominant flux is a sharp reduction in the number of sectors and a loss in magnetic flux, as documented from the Voyager 1 magnetic field and flow data.« less
NASA Astrophysics Data System (ADS)
Bashkanov, M.; Skorodko, T.; Clement, H.; Watts, D. P.
Several new findings in the four, five and six quark systems reheat the interest in the field of multiquark states (beyond the trivial qq¯ and qqq). A lot of progress has recently been made in the 6q sector, on both the theoretical and experimental side. A resonance like structure observed in double-pionic fusion to the deuteron, at M = 2.38 GeV with Γ = 70 MeV and I(JP) = 0(3+) has been consistently observed in a wealth of reaction channels, supporting the existence of a resonant dibaryon state - the d∗(2380). These studies include measurement of all the principle strong decay channels in pn collisions in the quasifree mode by the WASA-at-COSY and HADES collaborations. The internal structure of the d∗(2380) is largely unknown. It can contain various ”hidden color” 6q configurations, ΔΔ molecular states with angular momentum L = 0,2,4,6 as well as meson-assisted dressed dibaryon structures. The large set of experimental data obtained to date gives some constraints on the internal structure of the d∗(2380) dibaryon, but does not settle the issue. The d∗ is the only multiquark state which can be produced copiously at current facilities, offering unique access to information beyond its basic quantum numbers, particularly its physical size and internal structure.
Holographic quantitative imaging of sample hidden by turbid medium or occluding objects
NASA Astrophysics Data System (ADS)
Bianco, V.; Miccio, L.; Merola, F.; Memmolo, P.; Gennari, O.; Paturzo, Melania; Netti, P. A.; Ferraro, P.
2015-03-01
Digital Holography (DH) numerical procedures have been developed to allow imaging through turbid media. A fluid is considered turbid when dispersed particles provoke strong light scattering, thus destroying the image formation by any standard optical system. Here we show that sharp amplitude imaging and phase-contrast mapping of object hidden behind turbid medium and/or occluding objects are possible in harsh noise conditions and with a large field-of view by Multi-Look DH microscopy. In particular, it will be shown that both amplitude imaging and phase-contrast mapping of cells hidden behind a flow of Red Blood Cells can be obtained. This allows, in a noninvasive way, the quantitative evaluation of living processes in Lab on Chip platforms where conventional microscopy techniques fail. The combination of this technique with endoscopic imaging can pave the way for the holographic blood vessel inspection, e.g. to look for settled cholesterol plaques as well as blood clots for a rapid diagnostics of blood diseases.
Robertson, Colin; Sawford, Kate; Gunawardana, Walimunige S. N.; Nelson, Trisalyn A.; Nathoo, Farouk; Stephen, Craig
2011-01-01
Surveillance systems tracking health patterns in animals have potential for early warning of infectious disease in humans, yet there are many challenges that remain before this can be realized. Specifically, there remains the challenge of detecting early warning signals for diseases that are not known or are not part of routine surveillance for named diseases. This paper reports on the development of a hidden Markov model for analysis of frontline veterinary sentinel surveillance data from Sri Lanka. Field veterinarians collected data on syndromes and diagnoses using mobile phones. A model for submission patterns accounts for both sentinel-related and disease-related variability. Models for commonly reported cattle diagnoses were estimated separately. Region-specific weekly average prevalence was estimated for each diagnoses and partitioned into normal and abnormal periods. Visualization of state probabilities was used to indicate areas and times of unusual disease prevalence. The analysis suggests that hidden Markov modelling is a useful approach for surveillance datasets from novel populations and/or having little historical baselines. PMID:21949763
El Yazid Boudaren, Mohamed; Monfrini, Emmanuel; Pieczynski, Wojciech; Aïssani, Amar
2014-11-01
Hidden Markov chains have been shown to be inadequate for data modeling under some complex conditions. In this work, we address the problem of statistical modeling of phenomena involving two heterogeneous system states. Such phenomena may arise in biology or communications, among other fields. Namely, we consider that a sequence of meaningful words is to be searched within a whole observation that also contains arbitrary one-by-one symbols. Moreover, a word may be interrupted at some site to be carried on later. Applying plain hidden Markov chains to such data, while ignoring their specificity, yields unsatisfactory results. The Phasic triplet Markov chain, proposed in this paper, overcomes this difficulty by means of an auxiliary underlying process in accordance with the triplet Markov chains theory. Related Bayesian restoration techniques and parameters estimation procedures according to the new model are then described. Finally, to assess the performance of the proposed model against the conventional hidden Markov chain model, experiments are conducted on synthetic and real data.
Cosmological signatures of a UV-conformal standard model.
Dorsch, Glauber C; Huber, Stephan J; No, Jose Miguel
2014-09-19
Quantum scale invariance in the UV has been recently advocated as an attractive way of solving the gauge hierarchy problem arising in the standard model. We explore the cosmological signatures at the electroweak scale when the breaking of scale invariance originates from a hidden sector and is mediated to the standard model by gauge interactions (gauge mediation). These scenarios, while being hard to distinguish from the standard model at LHC, can give rise to a strong electroweak phase transition leading to the generation of a large stochastic gravitational wave signal in possible reach of future space-based detectors such as eLISA and BBO. This relic would be the cosmological imprint of the breaking of scale invariance in nature.
Maxwell's Demon Through the Looking Glass
NASA Astrophysics Data System (ADS)
Silagadze, Z. K.
2007-01-01
Mechanical Maxwell's demons, such as Smoluchowski's trapdoor and Feynman's ratchet and pawl need external energy source to operate. If you cease to feed a demon the Second Law of thermodynamics will quickly stop its operation. Nevertheless, if the parity is an unbroken symmetry of nature, it may happen that a small modification leads to demons which do not need feeding. Such demons can act like perpetuum mobiles of the second kind: extract heat energy from only one reservoir, use it to do work and be isolated from the rest of ordinary world. Yet the Second Law is not violated because the demons pay their entropy cost in the hidden (mirror) sector of the world by emitting mirror photons.
Portal Connecting Dark Photons and Axions.
Kaneta, Kunio; Lee, Hye-Sung; Yun, Seokhoon
2017-03-10
The dark photon and the axion (or axionlike particle) are popular light particles of the hidden sector. Each of them has been actively searched for through the couplings called the vector portal and the axion portal. We introduce a new portal connecting the dark photon and the axion (axion-photon-dark photon, axion-dark photon-dark photon), which emerges in the presence of the two particles. This dark axion portal is genuinely new couplings, not just from a product of the vector portal and the axion portal, because of the internal structure of these couplings. We present a simple model that realizes the dark axion portal and discuss why it warrants a rich phenomenology.
NASA Astrophysics Data System (ADS)
Getachew, Tibebu; Virtanen, Ilpo; Mursula, Kalevi
2017-11-01
The photospheric magnetic field is the source of the coronal and heliospheric magnetic fields (HMF), but their mutual correspondence is non-trivial and depends on the phase of the solar cycle. The photospheric field during the HMF sector crossings observed at 1 AU has been found to contain enhanced field intensities and definite polarity ordering, forming regions called Hale boundaries. Here we separately study the structure of the photospheric field during the HMF sector crossings during Solar Cycles 21 - 24 for the four phases of each solar cycle. We use a refined version of Svalgaard's list of major HMF sector crossings, mapped to the Sun using the solar wind speed observed at Earth, and the daily level-3 magnetograms of the photospheric field measured at the Wilcox Solar Observatory in 1976 - 2016. We find that the structure of the photospheric field corresponding to the HMF sector crossings and the existence and properties of the corresponding Hale bipolar regions varies significantly with solar cycle, solar cycle phase, and hemisphere. The Hale boundaries in more than half of the ascending, maximum, and declining phases are clear and statistically significant. The clearest Hale boundaries are found during the (+,-) HMF crossings in the northern hemisphere of odd Cycles 21 and 23, but less systematical during the (+,-) crossings in the southern hemisphere of even Cycles 22 and 24. No similar difference between odd and even cycles is found for the (-,+) crossings. This shows that the northern hemisphere has a more organized Hale pattern overall. The photospheric field distribution also depicts a larger area for the field of the northern hemisphere during the declining and minimum phases, in a good agreement with the bashful ballerina phenomenon.
2012-10-24
The image on the left shows a portion of our sky, called the Boötes field, in infrared light, while the image on the right shows a mysterious, background infrared glow captured by NASA Spitzer Space Telescope in the same region of sky.
2010-09-29
NASA Wide-field Infrared Survey Explorer captured this image of a hidden star-forming cloud of dust and gas located in the constellation of Cepheus. What appears to the naked eye as the blackness of space is in fact a dark nebula.
Heteronomy in the arts field: state funding and British arts organizations.
Alexander, Victoria D
2018-03-01
For Bourdieu, the field of cultural production is comprised of an autonomous and a heteronomous sector. A heteronomous sector is one that is interpenetrated by the commercial field. I discuss an arena that, until recently, was part of the relatively autonomous sector in the field of cultural production - the supported arts sector in the United Kingdom - and argue that it became more heteronomous, due to the penetration by the state. Heteronomy due to the commercial field is present but secondary to, and driven by, the actions of the state. Political parties' attempts to diffuse and legitimate a particular economic ideology have led to state demands that arts institutions adopt neoliberal business practices in exchange for funding. Government giving to the arts, previously at arm's length, proved to be a Faustian bargain that demanded significant repayment in the form of lost autonomy. Coercive pressures from the state, enacted over time, show how the domination of one field over another can occur, even when the domination is resisted. © London School of Economics and Political Science 2017.
NASA Astrophysics Data System (ADS)
Wang, Qingdong; Li, Yuzhi; Ma, Qingyu; Guo, Gepu; Tu, Juan; Zhang, Dong
2018-01-01
In order to improve the capability of particle trapping close to the source plane, theoretical and experimental studies on near-field multiple traps of paraxial acoustic vortices (AVs) with a strengthened acoustic gradient force (AGF) generated by a sector transducer array were conducted. By applying the integration of point source radiation, numerical simulations for the acoustic fields generated by the sector transducer array were conducted and compared with those produced by the circular transducer array. It was proved that strengthened AGFs of near-field multiple AVs with higher peak pressures and smaller vortex radii could be produced by the sector transducer array with a small topological charge. The axial distributions of the equivalent potential gradient indicated that the AGFs of paraxial AVs in the near field were much higher than those in the far field, and the distances at the near-field vortex antinodes were also proved to be the ideal trapping positions with relatively higher AGFs. With the established 8-channel AV generation system, theoretical studies were also verified by the experimental measurements of pressure and phase for AVs with various topological charges. The formation of near-field multiple paraxial AVs was verified by the cross-sectional circular pressure distributions with perfect phase spirals around central pressure nulls, and was also proved by the vortex nodes and antinodes along the center axis. The favorable results demonstrated the feasibility of generating near-field multiple traps of paraxial AVs with strengthened AGF using the sector transducer array, and suggested the potential applications of close-range particle trapping in biomedical engineering.
Social Effects on Rat Spatial Choice in an Open Field Task
ERIC Educational Resources Information Center
Keller, Matthew R.; Brown, Michael F.
2011-01-01
Pairs of rats foraged in trials either together or separately in an open field apparatus for pellets hidden in discreet locations in a 5 x 5 matrix. Trial duration was either 1 or 4 min. The tendency to choose locations that had earlier been visited by another rat was examined by comparing the choices made in the presence and absence of the other…
Relativistic harmonic oscillator revisited
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bars, Itzhak
2009-02-15
The familiar Fock space commonly used to describe the relativistic harmonic oscillator, for example, as part of string theory, is insufficient to describe all the states of the relativistic oscillator. We find that there are three different vacua leading to three disconnected Fock sectors, all constructed with the same creation-annihilation operators. These have different spacetime geometric properties as well as different algebraic symmetry properties or different quantum numbers. Two of these Fock spaces include negative norm ghosts (as in string theory), while the third one is completely free of ghosts. We discuss a gauge symmetry in a worldline theory approachmore » that supplies appropriate constraints to remove all the ghosts from all Fock sectors of the single oscillator. The resulting ghost-free quantum spectrum in d+1 dimensions is then classified in unitary representations of the Lorentz group SO(d,1). Moreover, all states of the single oscillator put together make up a single infinite dimensional unitary representation of a hidden global symmetry SU(d,1), whose Casimir eigenvalues are computed. Possible applications of these new results in string theory and other areas of physics and mathematics are briefly mentioned.« less
Leptonic CP phase determined by an equation involving PMNS matrix elements
NASA Astrophysics Data System (ADS)
Ke, Hong-Wei; Zhou, Jia-Hui; Li, Xue-Qian
2017-04-01
Several approximate equalities among the matrix elements of the Cabibbo-Kobayashi-Maskawa (CKM) and Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrices imply that hidden symmetries may exist and be common for both quark and neutrino sectors. The charge parity (CP) phase of the CKM matrix ({δ }{CKM}) is involved in these equalities and can be investigated when these equalities turn into several equations. As we substitute those experimentally measured values of the three mixing angles into the equations for quarks, it is noted that one of the equations which holds exactly has a solution {δ }{CKM}=({68.95}-1.15+1.15)^\\circ . That value accords with ({69.1}-3.85+2.02)^\\circ determined from available data. Generalizing the scenario to the lepton sector, the same equality determines the leptonic CP phase {δ }{PMNS} to be ({275.20}-1.15+1.15)^\\circ . Thus we predict the value of {δ }{PMNS} from the equation. So far there is no direct measurement on {δ }{PMNS}, but a recent analysis based on the neutrino oscillation data prefers a phase close to 270°.
Partially composite particle physics with and without supersymmetry
NASA Astrophysics Data System (ADS)
Kramer, Thomas A.
Theories in which the Standard Model fields are partially compositeness provide elegant and phenomenologically viable solutions to the Hierarchy Problem. In this thesis we will study types of models from two different perspectives. We first derive an effective field theory describing the interactions of the Standard Models fields with their lightest composite partners based on two weakly coupled sectors. Technically, via the AdS/CFT correspondence, our model is dual to a highly deconstructed theory with a single warped extra-dimension. This two sector theory provides a simplified approach to the phenomenology of this important class of theories. We then use this effective field theoretic approach to study models with weak scale accidental supersymmetry. Particularly, we will investigate the possibility that the Standard Model Higgs field is a member of a composite supersymmetric sector interacting weakly with the known Standard Model fields.
Equatorial ionospheric response to the 2015 St. Patrick's Day magnetic storm
NASA Astrophysics Data System (ADS)
Huang, C.; Wilson, G. R.; Hairston, M. R.; Zhang, Y.; Wang, W.; Liu, J.
2016-12-01
The geomagnetic storm on 17 March 2015 was the strongest storm during solar cycle 24 and caused significant disturbances in the global ionosphere. We present measurements of the Defense Meteorological Satellite Program satellites and identify the dynamic response of the equatorial ionosphere to the storm. Large penetration and disturbance dynamo electric fields are detected in both the dusk and the dawn sectors, and the characteristics of the electric fields are dramatically different in the two local time sectors. Penetration electric field is strong in the evening sector, but disturbance dynamo electric field is dominant in the dawn sector. The dynamo process is first observed in the post-midnight sector 4 hours after the beginning of the storm main phase and lasts for 31 hours, covering the major part of the storm main phase and the initial 20 hours of the recovery phase. The dynamo vertical ion drift is upward (up to 200 m/s) in the post-midnight sector and downward (up to 80 m/s) in the early morning sector. The dynamo zonal ion drift is westward at these locations and reaches 100 m/s. The dynamo process causes large enhancements of the oxygen ion concentration, and the variations of the oxygen ion concentration are well correlated with the vertical ion drift. The observations suggest that disturbance dynamo becomes dominant in the post-midnight equatorial ionosphere even during the storm main phase when disturbance neutral winds arrive there. The results provide new insight into storm-time equatorial ionospheric dynamics.
Multiscale hidden Markov models for photon-limited imaging
NASA Astrophysics Data System (ADS)
Nowak, Robert D.
1999-06-01
Photon-limited image analysis is often hindered by low signal-to-noise ratios. A novel Bayesian multiscale modeling and analysis method is developed in this paper to assist in these challenging situations. In addition to providing a very natural and useful framework for modeling an d processing images, Bayesian multiscale analysis is often much less computationally demanding compared to classical Markov random field models. This paper focuses on a probabilistic graph model called the multiscale hidden Markov model (MHMM), which captures the key inter-scale dependencies present in natural image intensities. The MHMM framework presented here is specifically designed for photon-limited imagin applications involving Poisson statistics, and applications to image intensity analysis are examined.
New infinite-dimensional hidden symmetries for heterotic string theory
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gao Yajun
The symmetry structures of two-dimensional heterotic string theory are studied further. A (2d+n)x(2d+n) matrix complex H-potential is constructed and the field equations are extended into a complex matrix formulation. A pair of Hauser-Ernst-type linear systems are established. Based on these linear systems, explicit formulations of new hidden symmetry transformations for the considered theory are given and then these symmetry transformations are verified to constitute infinite-dimensional Lie algebras: the semidirect product of the Kac-Moody o(d,d+n-circumflex) and Virasoro algebras (without center charges). These results demonstrate that the heterotic string theory under consideration possesses more and richer symmetry structures than previously expected.
Hidden symmetry and nonlinear paraxial atom optics
DOE Office of Scientific and Technical Information (OSTI.GOV)
Impens, Francois
2009-12-15
A hidden symmetry of the nonlinear wave equation is exploited to analyze the propagation of paraxial and uniform atom-laser beams in time-independent and quadratic transverse potentials with cylindrical symmetry. The quality factor and the paraxial ABCD formalism are generalized to account exactly for mean-field interaction effects in such beams. Using an approach based on moments, these theoretical tools provide a simple yet exact picture of the interacting beam profile evolution. Guided atom laser experiments are discussed. This treatment addresses simultaneously optical and atomic beams in a unified manner, exploiting the formal analogy between nonlinear optics, nonlinear paraxial atom optics, andmore » the physics of two-dimensional Bose-Einstein condensates.« less
ARPA surveillance technology for detection of targets hidden in foliage
NASA Astrophysics Data System (ADS)
Hoff, Lawrence E.; Stotts, Larry B.
1994-02-01
The processing of large quantities of synthetic aperture radar data in real time is a complex problem. Even the image formation process taxes today's most advanced computers. The use of complex algorithms with multiple channels adds another dimension to the computational problem. Advanced Research Projects Agency (ARPA) is currently planning on using the Paragon parallel processor for this task. The Paragon is small enough to allow its use in a sensor aircraft. Candidate algorithms will be implemented on the Paragon for evaluation for real time processing. In this paper ARPA technology developments for detecting targets hidden in foliage are reviewed and examples of signal processing techniques on field collected data are presented.
Bereznoy, A V; Saygitov, R T
Digital revolution is one of the major global trends resulting in the unprecedented scale and depth of penetration of information and communication technologies into all sectors of national economy, including healthcare. The development of this trend brought about high expectations related to the improvement of quality of medical assistance, accessibility and economic efficiency of healthcare services. However, euphoria of the first steps of digital revolution is passing now, opening doors to more realistic analysis of opportunities and conditions of realization of the true potential hidden in the digital transformation of healthcare. More balanced perception of the peculiarities of innovation processes in the sector is coming together with understanding of the serious barriers, hampering implementation of the new ideas and practices due to complicated interweaving of social, economic, ethical and psychological factors. When taking into account the industry specifics it becomes evident that digital revolution cannot be a quick turnaround but rather would pass a number of phases and is likely to last more than one decade. In this context the article focuses on the prospects of the new business models, capable of making significant changes in today’s economic landscape of the sector (including uber-medicine, retail clinics, retainer medicine, network models of medical services). The authors also provide assessment of the current situation and perspectives of digital healthcare development in Russia.
N =1 supergravitational heterotic galileons
NASA Astrophysics Data System (ADS)
Deen, Rehan; Ovrut, Burt
2017-11-01
Heterotic M -theory consists of a five-dimensional manifold of the form S 1 / Z 2 × M 4. It has been shown that one of the two orbifold planes, the "observable" sector, can have a low energy particle spectrum which is precisely the N = 1 super-symmetric standard model with three right-handed neutrino chiral supermultiplets. The other orbifold plane constitutes a "hidden" sector which, since its communication with the observable sector is suppressed, will be ignored in this paper. However, the finite fifth-dimension allows for the existence of three-brane solitons which, in order to render the vacuum anomaly free, must appear. That is, heterotic M -theory provides a natural framework for brane-world cosmological scenarios coupled to realistic particle physics. The complete worldvolume action of such three-branes is unknown. Here, treating these solitons as probe branes, we construct their scalar worldvolume Lagrangian as a derivative expansion of the heterotic DBI action. In analogy with similar calculations in the M 5 and AdS 5 context, this leads to the construction of "heterotic Galileons". However, realistic vacua of heterotic M -theory are necessarily N = 1 supersymmetric in four dimensions. Hence, we proceed to supersymmetrize the three-brane worldvolume action, first in flat superspace and then extend the results to N = 1 supergravity. Such a worldvolume action may lead to interesting cosmology, such as "bouncing" universe models, by allowing for the violation of the Null Energy Condition (NEC).
Mehrolhassani, Mohammad Hossein; Emami, Mozhgan
2013-01-01
Background: Change theories provide an opportunity for organizational managers to plan, monitor and evaluate changes using a framework which enable them, among others, to show a fast response to environmental fluctuations and to predict the changing patterns of individuals and technology. The current study aimed to explore whether the change in the public accounting system of the Iranian health sector has followed Kurt Lewin’s change theory or not. Methods: This study which adopted a mixed methodology approach, qualitative and quantitative methods, was conducted in 2012. In the first phase of the study, 41 participants using purposive sampling and in the second phase, 32 affiliated units of Kerman University of Medical Sciences (KUMS) were selected as the study sample. Also, in phase one, we used face-to-face in-depth interviews (6 participants) and the quote method (35 participants) for data collection. We used a thematic framework analysis for analyzing data. In phase two, a questionnaire with a ten-point Likert scale was designed and then, data were analyzed using descriptive indicators, principal component and factorial analyses. Results: The results of phase one yielded a model consisting of four categories of superstructure, apparent infrastructure, hidden infrastructure and common factors. By linking all factors, totally, 12 components based on the quantitative results showed that the state of all components were not satisfactory at KUMS (5.06±2.16). Leadership and management; and technology components played the lowest and the greatest roles in implementing the accrual accounting system respectively. Conclusion: The results showed that the unfreezing stage did not occur well and the components were immature, mainly because the emphasis was placed on superstructure components rather than the components of hidden infrastructure. The study suggests that a road map should be developed in the financial system based on Kurt Lewin’s change theory and the model presented in this paper underpins the change management in any organizations. PMID:24596885
Adding Spice to Vanilla LCDM simulations: From Alternative Cosmologies to Lighting up Galaxies
NASA Astrophysics Data System (ADS)
Jahan Elahi, Pascal
2015-08-01
Cold Dark Matter simulations have formed the backbone of our theoretical understanding of cosmological structure formation. Predictions from the Lambda Cold Dark Matter (LCDM) cosmology, in which the Universe contains two major dark components, namely Dark Matter and Dark Energy, are in excellent agreement with the Large-Scale Structures observed, i.e., the distribution of galaxies across cosmic time. However, this paradigm is in tension with observations at small-scales, from the number and properties of satellite galaxies around galaxies such as the Milky Way and Andromeda, to the lensing statistics of massive galaxy clusters. I will present several alternative models of cosmology (from Warm Dark Matter to coupled Dark Matter-Dark Energy models) and how they compare to vanilla LCDM by studying formation of groups and clusters dark matter only and adiabatic hydrodynamical zoom simulations. I will show how modifications to the dark sector can lead to some surprising results. For example, Warm Dark Matter, so often examined on small satellite galaxies scales, can be probed observationally using weak lensing at cluster scales. Coupled dark sectors, where dark matter decays into dark energy and experiences an effective gravitational potential that differs from that experienced by normal matter, is effectively hidden away from direct observations of galaxies. Studies like these are vital if we are to pinpoint observations which can look for unique signatures of the physics that governs the hidden Universe. Of course, all of these predictions are unfortunately affected by uncertain galaxy formation physics. I will end by presenting results from a comparison study of numerous hydrodynamical codes, the nIFTY cluster comparison project, and how even how purely adiabatic simulations run with different codes give in quite different galaxy populations. The galaxies that form in these simulations, which all attempt to reproduce the observed galaxy population via not unreasonable subgrid physics, can and do vary in stellar mass, morphology and gas fraction.
Mehrolhassani, Mohammad Hossein; Emami, Mozhgan
2013-11-01
Change theories provide an opportunity for organizational managers to plan, monitor and evaluate changes using a framework which enable them, among others, to show a fast response to environmental fluctuations and to predict the changing patterns of individuals and technology. The current study aimed to explore whether the change in the public accounting system of the Iranian health sector has followed Kurt Lewin's change theory or not. This study which adopted a mixed methodology approach, qualitative and quantitative methods, was conducted in 2012. In the first phase of the study, 41 participants using purposive sampling and in the second phase, 32 affiliated units of Kerman University of Medical Sciences (KUMS) were selected as the study sample. Also, in phase one, we used face-to-face in-depth interviews (6 participants) and the quote method (35 participants) for data collection. We used a thematic framework analysis for analyzing data. In phase two, a questionnaire with a ten-point Likert scale was designed and then, data were analyzed using descriptive indicators, principal component and factorial analyses. The results of phase one yielded a model consisting of four categories of superstructure, apparent infrastructure, hidden infrastructure and common factors. By linking all factors, totally, 12 components based on the quantitative results showed that the state of all components were not satisfactory at KUMS (5.06±2.16). Leadership and management; and technology components played the lowest and the greatest roles in implementing the accrual accounting system respectively. The results showed that the unfreezing stage did not occur well and the components were immature, mainly because the emphasis was placed on superstructure components rather than the components of hidden infrastructure. The study suggests that a road map should be developed in the financial system based on Kurt Lewin's change theory and the model presented in this paper underpins the change management in any organizations.
Noninvasive, near-field terahertz imaging of hidden objects using a single-pixel detector.
Stantchev, Rayko Ivanov; Sun, Baoqing; Hornett, Sam M; Hobson, Peter A; Gibson, Graham M; Padgett, Miles J; Hendry, Euan
2016-06-01
Terahertz (THz) imaging can see through otherwise opaque materials. However, because of the long wavelengths of THz radiation (λ = 400 μm at 0.75 THz), far-field THz imaging techniques suffer from low resolution compared to visible wavelengths. We demonstrate noninvasive, near-field THz imaging with subwavelength resolution. We project a time-varying, intense (>100 μJ/cm(2)) optical pattern onto a silicon wafer, which spatially modulates the transmission of synchronous pulse of THz radiation. An unknown object is placed on the hidden side of the silicon, and the far-field THz transmission corresponding to each mask is recorded by a single-element detector. Knowledge of the patterns and of the corresponding detector signal are combined to give an image of the object. Using this technique, we image a printed circuit board on the underside of a 115-μm-thick silicon wafer with ~100-μm (λ/4) resolution. With subwavelength resolution and the inherent sensitivity to local conductivity, it is possible to detect fissures in the circuitry wiring of a few micrometers in size. THz imaging systems of this type will have other uses too, where noninvasive measurement or imaging of concealed structures is necessary, such as in semiconductor manufacturing or in ex vivo bioimaging.
Detection and Localization of Money Bills Concealed Behind Wooden Walls Using Compton Scattering
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wart, Jason A. van; Hussein, Esam M.A.; Waller, Edward J
2005-05-15
This work presents a portable device for detecting visually obscured contraband money bills that may be hidden within conventional household walls for the purpose of avoiding confiscation. The device utilizes the Compton backscattering of photons emitted from a collimated {sup 241}Am source. The scattered photons are detected with a thin NaI(Tl) detector, either over a wide field of view for surface scanning of the wall or within a confined view field for depth scanning. The design of the device was optimized for best density contrast and highest count rate for a given source activity. It was shown that the minimummore » detectable amount of contraband, with >95% confidence level, is 86 paper bills. The contraband was detectable when hidden in household walls made of gyprock or wooden paneling, even when masked by higher density materials such as metallic piping. The device's capability exceeded those of commercially available density-based portable contraband detectors.« less
Castillo-Barnes, Diego; Peis, Ignacio; Martínez-Murcia, Francisco J.; Segovia, Fermín; Illán, Ignacio A.; Górriz, Juan M.; Ramírez, Javier; Salas-Gonzalez, Diego
2017-01-01
A wide range of segmentation approaches assumes that intensity histograms extracted from magnetic resonance images (MRI) have a distribution for each brain tissue that can be modeled by a Gaussian distribution or a mixture of them. Nevertheless, intensity histograms of White Matter and Gray Matter are not symmetric and they exhibit heavy tails. In this work, we present a hidden Markov random field model with expectation maximization (EM-HMRF) modeling the components using the α-stable distribution. The proposed model is a generalization of the widely used EM-HMRF algorithm with Gaussian distributions. We test the α-stable EM-HMRF model in synthetic data and brain MRI data. The proposed methodology presents two main advantages: Firstly, it is more robust to outliers. Secondly, we obtain similar results than using Gaussian when the Gaussian assumption holds. This approach is able to model the spatial dependence between neighboring voxels in tomographic brain MRI. PMID:29209194
Topography of Power Relations in Slovak Preschool Sector Based on Bourdieu's Field Theory
ERIC Educational Resources Information Center
Kašcák, Ondrej; Pupala, Branislav
2017-01-01
The article analyses the Slovak preschool education sector using Bourdieu's field theory. It describes stable and volatile points in the evolution of preschool education in terms of the power games occurring within the specific social field of power relations shaped during these games. It explores the groups of powerful players that represent the…
Muth, Claudia; Raab, Marius H; Carbon, Claus-Christian
2016-01-01
Research in the field of psychological aesthetics points to the appeal of stimuli which defy easy recognition by being "semantically unstable" but which still allow for creating meaning-in the ongoing process of elaborative perception or as an end product of the entire process. Such effects were reported for hidden images (Muth and Carbon, 2013) as well as Cubist artworks concealing detectable-although fragmented-objects (Muth et al., 2013). To test the stability of the relationship between semantic determinacy and appreciation across different episodic contexts, 30 volunteers evaluated an artistic movie continuously on visual determinacy or liking via the Continuous Evaluation Procedure (CEP, Muth et al., 2015b). The movie consisted of five episodes with emerging Gestalts. In the first between-participants condition, the hidden Gestalts in the movie episodes were of increasing determinacy, in the second condition, the episodes showed decreasing determinacies of hidden Gestalts. In the increasing-determinacy group, visual determinacy was rated higher and showed better predictive quality for liking than in the decreasing-determinacy group. Furthermore, when the movie started with low visual determinacy of hidden Gestalts, unexpectedly strong increases in visual determinacy had a bigger effect on liking than in the condition which allowed for weaker Gestalt recognition after having started with highly determinate Gestalts. The resulting pattern calls for consideration of the episodic context when examining art appreciation.
Quality Guidance: A Sectoral Analysis. NICEC Project Report.
ERIC Educational Resources Information Center
Watts, A. G.; Sadler, Jackie
This report reviews the structure of the guidance field and provides a sector-by-sector analysis of current quality assurance arrangements in the United Kingdom. Part 1 presents an outline of the guidance sector, including some key concepts, structures, and roles. It defines guidance and other terms; discusses the three main categories…
Anomaly on Superspace of Time Series Data
NASA Astrophysics Data System (ADS)
Capozziello, Salvatore; Pincak, Richard; Kanjamapornkul, Kabin
2017-11-01
We apply the G-theory and anomaly of ghost and antighost fields in the theory of supersymmetry to study a superspace over time series data for the detection of hidden general supply and demand equilibrium in the financial market. We provide proof of the existence of a general equilibrium point over 14 extradimensions of the new G-theory compared with the M-theory of the 11 dimensions model of Edward Witten. We found that the process of coupling between nonequilibrium and equilibrium spinor fields of expectation ghost fields in the superspace of time series data induces an infinitely long exact sequence of cohomology from a short exact sequence of moduli state space model. If we assume that the financial market is separated into two topological spaces of supply and demand as the D-brane and anti-D-brane model, then we can use a cohomology group to compute the stability of the market as a stable point of the general equilibrium of the interaction between D-branes of the market. We obtain the result that the general equilibrium will exist if and only if the 14th Batalin-Vilkovisky cohomology group with the negative dimensions underlying 14 major hidden factors influencing the market is zero.
NASA Technical Reports Server (NTRS)
Burlaga, L. F.; Ness, N. F.
2011-01-01
The magnetic polarity pattern observed by Voyager 2 (V2) evolved with time from a nearly equal mixture of positive and negative polarity sectors in the sector zone from 2007.00 to 2007.67 to nearly uniform positive polarity (magnetic fields directed away from the Sun) in the unipolar zone from 2009.6 to 2010.3. This change was caused by the decreasing latitudinal extent of the sector zone, when the minimum extent of the heliospheric current sheet moved northward toward the solar equator as the solar activity associated with solar cycle 23 decreased a minimum in 2010. In the heliosheath, the distribution of daily averages of the magnetic field strength B was lognormal in the sector zone from 2008.83 to 2009.57 and Gaussian in the unipolar zone from 2009.57 to 2010.27. The distribution of daily increments of B was a Tsallis distribution (q-Gaussian distribution) with q = 1.66 +/- 0.010 in the sector zone and . Gaussian (q = 1.01+/-0.29) in the unipolar zone. The unipolar region appears to be in a relatively undisturbed equilibrium state.
Elderly Alcoholism: Implications for Human Service Education
ERIC Educational Resources Information Center
Beechem, Michael
2004-01-01
Incumbent upon those faculty who teach substance abuse courses is the need to integrate elderly alcoholism-related course content to encourage and adequately prepare university students to serve this "hidden" population. Course content would ideally include theories specific to loss-grief, aging, and alcoholism. In addition, field placement…
Space coding for sensorimotor transformations can emerge through unsupervised learning.
De Filippo De Grazia, Michele; Cutini, Simone; Lisi, Matteo; Zorzi, Marco
2012-08-01
The posterior parietal cortex (PPC) is fundamental for sensorimotor transformations because it combines multiple sensory inputs and posture signals into different spatial reference frames that drive motor programming. Here, we present a computational model mimicking the sensorimotor transformations occurring in the PPC. A recurrent neural network with one layer of hidden neurons (restricted Boltzmann machine) learned a stochastic generative model of the sensory data without supervision. After the unsupervised learning phase, the activity of the hidden neurons was used to compute a motor program (a population code on a bidimensional map) through a simple linear projection and delta rule learning. The average motor error, calculated as the difference between the expected and the computed output, was less than 3°. Importantly, analyses of the hidden neurons revealed gain-modulated visual receptive fields, thereby showing that space coding for sensorimotor transformations similar to that observed in the PPC can emerge through unsupervised learning. These results suggest that gain modulation is an efficient coding strategy to integrate visual and postural information toward the generation of motor commands.
Topology versus Anderson localization: Nonperturbative solutions in one dimension
NASA Astrophysics Data System (ADS)
Altland, Alexander; Bagrets, Dmitry; Kamenev, Alex
2015-02-01
We present an analytic theory of quantum criticality in quasi-one-dimensional topological Anderson insulators. We describe these systems in terms of two parameters (g ,χ ) representing localization and topological properties, respectively. Certain critical values of χ (half-integer for Z classes, or zero for Z2 classes) define phase boundaries between distinct topological sectors. Upon increasing system size, the two parameters exhibit flow similar to the celebrated two-parameter flow of the integer quantum Hall insulator. However, unlike the quantum Hall system, an exact analytical description of the entire phase diagram can be given in terms of the transfer-matrix solution of corresponding supersymmetric nonlinear sigma models. In Z2 classes we uncover a hidden supersymmetry, present at the quantum critical point.
Scalar field collapse in Gauss-Bonnet gravity
NASA Astrophysics Data System (ADS)
Banerjee, Narayan; Paul, Tanmoy
2018-02-01
We consider a "scalar-Einstein-Gauss-Bonnet" theory in four dimension, where the scalar field couples non-minimally with the Gauss-Bonnet (GB) term. This coupling with the scalar field ensures the non-topological character of the GB term. In this scenario, we examine the possibility for collapsing of the scalar field. Our result reveals that such a collapse is possible in the presence of Gauss-Bonnet gravity for suitable choices of parametric regions. The singularity formed as a result of the collapse is found to be a curvature singularity which is hidden from the exterior by an apparent horizon.
Individual Difference Effects in Human-Computer Interaction
1991-10-01
Dependence/Independence is probably the one which has received the most study (well over 300 studies of this dimension are reported in the literaturel). The...participated in the study . The subjects were classified into high analytical/field independent and low analytical/ field dependent on the tasis of... on the basis of the Hidden Figures Test (French, Ekstrom$, and Price, 1963). Stimulus 21 dimensionu of color and form were used. Results of this study
2012-07-01
units made from the various sensors. This was because the different types of ME laminates have different electrical properties ( resistance and...DC resistance of a sensor (Rdc) 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT: SAR 18. NUMBER OF PAGES 338 19a. NAME OF...3.3.6. Electric -field tuning effect ..................................................................70 A.3.4. Dielectric loss noise reduction
Specific feature of magnetooptical images of stray fields of magnets of various geometrical shapes
NASA Astrophysics Data System (ADS)
Ivanov, V. E.; Koveshnikov, A. V.; Andreev, S. V.
2017-08-01
Specific features of magnetooptical images (MOIs) of stray fields near the faces of prismatic hard magnetic elements have been studied. Attention has primarily been focused on MOIs of fields near faces oriented perpendicular to the magnetic moment of hard magnetic elements. With regard to the polar sensitivity, MOIs have practically uniform brightness and geometrically they coincide with the figures of the bases of the elements. With regard to longitudinal sensitivity, MOIs consist of several sectors, the number of which is determined by the number of angles of the image. Each angle is divided by the bisectrix into two sectors of different brightnesses; therefore, the MOI of a triangular magnet consists of three sectors. A rectangle consists of four sectors separated by the bisectrices of the interior angles. In all types of figures, these lines converge at the center of the figure and form a singular point of the source or sink type.
ERIC Educational Resources Information Center
Rothwell, Jonathan
2013-01-01
Workers in STEM (science, technology, engineering, and math) fields play a direct role in driving economic growth. Yet, because of how the STEM economy has been defined, policymakers have mainly focused on supporting workers with at least a bachelor's (BA) degree, overlooking a strong potential workforce of those with less than a BA. This report…
DOE Office of Scientific and Technical Information (OSTI.GOV)
Khrennikov, Andrei
We present fundamentals of a prequantum model with hidden variables of the classical field type. In some sense this is the comeback of classical wave mechanics. Our approach also can be considered as incorporation of quantum mechanics into classical signal theory. All quantum averages (including correlations of entangled systems) can be represented as classical signal averages and correlations.
Genders, Mathematics, and Feminisms.
ERIC Educational Resources Information Center
Damarin, Suzanne
Historical studies reveal that mathematics has been claimed as a private domain by men, while studies of the popular press document that women and girls are considered incompetent in that field. The study of gender and mathematics as viewed through feminism can create a new reading which exposes hidden assumptions, unwarranted conclusions, and…
The NGO-ization of Community Colleges: One (More) Manifestation of Globalization
ERIC Educational Resources Information Center
Quint-Rapoport, Mia
2006-01-01
In this essay the author discusses the effects of globalization on Canadian community colleges. She applies contemporary social theories culled from the fields of feminism, geography and political science to understand one hidden manifestation of globalization in community colleges: involvement in global civil society via participation in…
Advocacy: The Early Childhood Historian's Not-So-Hidden Agenda.
ERIC Educational Resources Information Center
Ranck, Edna Runnels
To examine how knowledge of history and politics informs the early education and child care field, this paper identifies sources of historical knowledge and unexamined underlying presuppositions frequently held by early childhood professionals which, if allowed to remain unchallenged, contribute to professional burn-out, repeated frustration at…
Predicting cloud-to-ground lightning with neural networks
NASA Technical Reports Server (NTRS)
Barnes, Arnold A., Jr.; Frankel, Donald; Draper, James Stark
1991-01-01
A neural network is being trained to predict lightning at Cape Canaveral for periods up to two hours in advance. Inputs consist of ground based field mill data, meteorological tower data, lightning location data, and radiosonde data. High values of the field mill data and rapid changes in the field mill data, offset in time, provide the forecasts or desired output values used to train the neural network through backpropagation. Examples of input data are shown and an example of data compression using a hidden layer in the neural network is discussed.
Trends of the World Input and Output Network of Global Trade
del Río-Chanona, Rita María; Grujić, Jelena; Jeldtoft Jensen, Henrik
2017-01-01
The international trade naturally maps onto a complex networks. Theoretical analysis of this network gives valuable insights about the global economic system. Although different economic data sets have been investigated from the network perspective, little attention has been paid to its dynamical behaviour. Here we take the World Input Output Data set, which has values of the annual transactions between 40 different countries of 35 different sectors for the period of 15 years, and infer the time interdependence between countries and sectors. As a measure of interdependence we use correlations between various time series of the network characteristics. First we form 15 primary networks for each year of the data we have, where nodes are countries and links are annual exports from one country to the other. Then we calculate the strengths (weighted degree) and PageRank of each country in each of the 15 networks for 15 different years. This leads to sets of time series and by calculating the correlations between these we form a secondary network where the links are the positive correlations between different countries or sectors. Furthermore, we also form a secondary network where the links are negative correlations in order to study the competition between countries and sectors. By analysing this secondary network we obtain a clearer picture of the mutual influences between countries. As one might expect, we find that political and geographical circumstances play an important role. However, the derived correlation network reveals surprising aspects which are hidden in the primary network. Sometimes countries which belong to the same community in the original network are found to be competitors in the secondary networks. E.g. Spain and Portugal are always in the same trade flow community, nevertheless secondary network analysis reveal that they exhibit contrary time evolution. PMID:28125656
Trends of the World Input and Output Network of Global Trade.
Del Río-Chanona, Rita María; Grujić, Jelena; Jeldtoft Jensen, Henrik
2017-01-01
The international trade naturally maps onto a complex networks. Theoretical analysis of this network gives valuable insights about the global economic system. Although different economic data sets have been investigated from the network perspective, little attention has been paid to its dynamical behaviour. Here we take the World Input Output Data set, which has values of the annual transactions between 40 different countries of 35 different sectors for the period of 15 years, and infer the time interdependence between countries and sectors. As a measure of interdependence we use correlations between various time series of the network characteristics. First we form 15 primary networks for each year of the data we have, where nodes are countries and links are annual exports from one country to the other. Then we calculate the strengths (weighted degree) and PageRank of each country in each of the 15 networks for 15 different years. This leads to sets of time series and by calculating the correlations between these we form a secondary network where the links are the positive correlations between different countries or sectors. Furthermore, we also form a secondary network where the links are negative correlations in order to study the competition between countries and sectors. By analysing this secondary network we obtain a clearer picture of the mutual influences between countries. As one might expect, we find that political and geographical circumstances play an important role. However, the derived correlation network reveals surprising aspects which are hidden in the primary network. Sometimes countries which belong to the same community in the original network are found to be competitors in the secondary networks. E.g. Spain and Portugal are always in the same trade flow community, nevertheless secondary network analysis reveal that they exhibit contrary time evolution.
Siqueira Freitas, Douglas; Wurr Rodak, Bruna; Rodrigues Dos Reis, André; de Barros Reis, Fabio; Soares de Carvalho, Teotonio; Schulze, Joachim; Carbone Carneiro, Marco A; Guimarães Guilherme, Luiz R
2018-01-01
Nickel (Ni)-a component of urease and hydrogenase-was the latest nutrient to be recognized as an essential element for plants. However, to date there are no records of Ni deficiency for annual species cultivated under field conditions, possibly because of the non-appearance of obvious and distinctive symptoms, i.e., a hidden (or latent) deficiency. Soybean, a crop cultivated on soils poor in extractable Ni, has a high dependence on biological nitrogen fixation (BNF), in which Ni plays a key role. Thus, we hypothesized that Ni fertilization in soybean genotypes results in a better nitrogen physiological function and in higher grain production due to the hidden deficiency of this micronutrient. To verify this hypothesis, two simultaneous experiments were carried out, under greenhouse and field conditions, with Ni supply of 0.0 or 0.5 mg of Ni kg -1 of soil. For this, we used 15 soybean genotypes and two soybean isogenic lines (urease positive, Eu3 ; urease activity-null, eu3-a , formerly eu3-e1 ). Plants were evaluated for yield, Ni and N concentration, photosynthesis, and N metabolism. Nickel fertilization resulted in greater grain yield in some genotypes, indicating the hidden deficiency of Ni in both conditions. Yield gains of up to 2.9 g per plant in greenhouse and up to 1,502 kg ha -1 in field conditions were associated with a promoted N metabolism, namely, leaf N concentration, ammonia, ureides, urea, and urease activity, which separated the genotypes into groups of Ni responsiveness. Nickel supply also positively affected photosynthesis in the genotypes, never causing detrimental effects, except for the eu3-a mutant, which due to the absence of ureolytic activity accumulated excess urea in leaves and had reduced yield. In summary, the effect of Ni on the plants was positive and the extent of this effect was controlled by genotype-environment interaction. The application of 0.5 mg kg -1 of Ni resulted in safe levels of this element in grains for human health consumption. Including Ni applications in fertilization programs may provide significant yield benefits in soybean production on low Ni soil. This might also be the case for other annual crops, especially legumes.
HIGH ENERGY PARTICLE ACCELERATOR
Courant, E.D.; Livingston, M.S.; Snyder, H.S.
1959-04-14
An improved apparatus is presented for focusing charged particles in an accelerator. In essence, the invention includes means for establishing a magnetic field in discrete sectors along the path of moving charged particles, the magnetic field varying in each sector in accordance with the relation. B = B/ sub 0/ STAln (r-r/sub 0/)/r/sub 0/!, where B/sub 0/ is the value of the magnetic field at the equilibrium orbit of radius r/sub 0/ of the path of the particles, B equals the magnetic field at the radius r of the chamber and n equals the magnetic field gradient index, the polarity of n being abruptly reversed a plurality of times as the particles travel along their arcuate path. With this arrangement, the particles are alternately converged towards the axis of their equillbrium orbit and diverged therefrom in successive sectors with a resultant focusing effect.
NASA Astrophysics Data System (ADS)
Su, S. Y.; Nayak, C.; Tsai, L. C.; Caton, R. G.; Groves, K. M.
2016-12-01
Variations of zonal drift and ionospheric VHF scintillations observed by a SCINDA station in Southern Taiwan during the St. Patrick's day geomagnetic storm are studied. Although scintillations were observed for 6 consecutive days before the storm, they were absence during the storm period. Data from VHF receivers, ionosonde and in situ plasma density observations from ESA's SWARM constellation are used to study the ionospheric irregularity/scintillation events in the Taiwanese sector to compare with what happened in the Indian sectors. The absence of scintillation in the Taiwanese sector during the storm period seems to be caused by a reduced pre-reversal enhancement (PRE) electric field from a westward prompt-penetration electric field (PPEF) during the storm. A low post-sunset ionosphere thus becomes unfavorable for the Rayleigh-Taylor instability to occur. On the contrary, the PPEFs were found to strongly enhance the PRE electric field in the Indian sector to cause the ionospheric irregularities/scintillations in the post-sunset sector. Zonal drift variations during the storm time are also discussed in conjunction with the irregularity/scintillation occurrences.
NASA Technical Reports Server (NTRS)
Langel, R. A.
1973-01-01
Variations in the scalar magnetic field (delta B) from the polar orbiting OGO 2, 4, and 6 spacecraft are examined as a function of altitude for times when the interplanetary magnetic field is toward the sun and for times when the interplanetary magnetic field away from the sun. This morphology is basically the same as that found when all data, irrespective of interplanetary magnetic sector, are averaged together. Differences in delta B occur, both between sectors and between seasons, which are similar in nature to variations in the surface delta Z found by Langel (1973c). The altitude variation of delta B at sunlit local times, together with delta Z at the earth's surface, demonstrates that the delta Z and delta B which varies with sector has an ionospheric source. Langel (1973b) showed that the positive delta B region in the dark portion of the hemisphere is due to at least two sources, the westward electrojet and an unidentified non-ionospheric source(s). Comparison of magnetic variations between season/sector at the surface and at the satellite, in the dark portion of the hemisphere, indicates that these variations are caused by variations in the latitudinally narrow electrojet currents and not by variations in the non-ionospheric source of delta B.
NASA Technical Reports Server (NTRS)
Villante, U.; Bruno, R.; Mariani, F.; Burlaga, L. F.; Ness, N. F.
1979-01-01
Simultaneous observations by Helios-1 and Helios-2 over four solar rotations were used to determine the latitudinal dependence of the polarity of the interplanetary magnetic field within plus or minus 7.23 deg of the solar equator and within 1 AU. The longitudinal and latitudinal positions of the sector boundary crossing are consistent with a warped sector boundary which extended from the sun to 1 AU and was inclined approximately 10 deg with respect to the heliographic equator. This is consistent with simultaneous Pioneer 11 observations, which showed unipolar fields at latitude approximately 16 deg at heliocentric distances greater than 3.5 AU. Two sectors were observed at southern latitudes; however, four sectors were observed at northern latitudes on two rotations, indicating a distortion from planarity of the sectory boundary surface.
How well can we really determine the scale of inflation?
NASA Astrophysics Data System (ADS)
Özsoy, Ogan; Sinha, Kuver; Watson, Scott
2015-05-01
A detection of primordial B modes has been heralded not only as a smoking gun for the existence of inflation, but also as a way to establish the scale at which inflation took place. In this paper we critically reinvestigate the connection between a detection of primordial gravity waves and the scale of inflation. We consider whether the presence of additional fields and nonadiabaticity during inflation may have provided an additional source of primordial B modes competitive with those of the quasi-de Sitter vacuum. In particular, we examine whether the additional sources could provide the dominant signal, which could lead to a misinterpretation of the scale of inflation. In light of constraints on the level of non-Gaussianity coming from Planck we find that only hidden sectors with strictly gravitationally strong couplings provide a feasible mechanism. The required model building is somewhat elaborate, and so we discuss possible UV completions in the context of type IIB orientifold compactifications with Ramond-Ramond axions. We find that an embedding is possible and that dangerous sinusoidal corrections can be suppressed through the compactification geometry. Our main result is that even when additional sources of primordial gravity waves are competitive with the inflaton, a positive B-mode detection would still be a relatively good indicator of the scale of inflation. This conclusion will be strengthened by future constraints on both non-Gaussianity and cosmic microwave background polarization.
Tertiary Student Transitions: Sectors, Fields, Impacts of and Reasons for Study--Support Document
ERIC Educational Resources Information Center
Fredman, Nick
2012-01-01
This paper examines the relationships between post-school educational fields and sectors and labour market considerations that appear to shape students' study decisions. It was found that pathways taken vary considerably by age, suggesting changes over time to patterns in tertiary education towards greater participation overall, a greater extent…
Hidden in the background: a local approach to CMB anomalies
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sánchez, Juan C. Bueno, E-mail: juan.c.bueno@correounivalle.edu.co
2016-09-01
We investigate a framework aiming to provide a common origin for the large-angle anomalies detected in the Cosmic Microwave Background (CMB), which are hypothesized as the result of the statistical inhomogeneity developed by different isocurvature fields of mass m ∼ H present during inflation. The inhomogeneity arises as the combined effect of ( i ) the initial conditions for isocurvature fields (obtained after a fast-roll stage finishing many e -foldings before cosmological scales exit the horizon), ( ii ) their inflationary fluctuations and ( iii ) their coupling to other degrees of freedom. Our case of interest is when thesemore » fields (interpreted as the precursors of large-angle anomalies) leave an observable imprint only in isolated patches of the Universe. When the latter intersect the last scattering surface, such imprints arise in the CMB. Nevertheless, due to their statistically inhomogeneous nature, these imprints are difficult to detect, for they become hidden in the background similarly to the Cold Spot. We then compute the probability that a single isocurvature field becomes inhomogeneous at the end of inflation and find that, if the appropriate conditions are given (which depend exclusively on the preexisting fast-roll stage), this probability is at the percent level. Finally, we discuss several mechanisms (including the curvaton and the inhomogeneous reheating) to investigate whether an initial statistically inhomogeneous isocurvature field fluctuation might give rise to some of the observed anomalies. In particular, we focus on the Cold Spot, the power deficit at low multipoles and the breaking of statistical isotropy.« less
Eavesdropping on insects hidden in soil and interior structures of plants.
Mankin, R W; Brandhorst-Hubbard, J; Flanders, K L; Zhang, M; Crocker, R L; Lapointe, S L; McCoy, C W; Fisher, J R; Weaver, D K
2000-08-01
Accelerometer, electret microphone, and piezoelectric disk acoustic systems were evaluated for their potential to detect hidden insect infestations in soil and interior structures of plants. Coleopteran grubs (the scarabaeids Phyllophaga spp. and Cyclocephala spp.) and the curculionids Diaprepes abbreviatus (L.) and Otiorhynchus sulcatus (F.) weighing 50-300 mg were detected easily in the laboratory and in the field except under extremely windy or noisy conditions. Cephus cinctus Norton (Hymenoptera: Cephidae) larvae weighing 1-12 mg could be detected in small pots of wheat in the laboratory by taking moderate precautions to eliminate background noise. Insect sounds could be distinguished from background noises by differences in frequency and temporal patterns, but insects of similarly sized species could not be distinguished easily from each other. Insect activity was highly variable among individuals and species, although D. abbreviatus grubs tended to be more active than those of O. sulcatus. Tests were done to compare acoustically predicted infestations with the contents of soil samples taken at recording sites. Under laboratory or ideal field conditions, active insects within approximately 30 cm were identified with nearly 100% reliability. In field tests under adverse conditions, the reliability decreased to approximately 75%. These results indicate that acoustic systems with vibration sensors have considerable potential as activity monitors in the laboratory and as field tools for rapid, nondestructive scouting and mapping of soil insect populations.
Split-orientation-modulated plasmon coupling in disk/sector dimers
NASA Astrophysics Data System (ADS)
Zhu, Xupeng; Chen, Yiqin; Shi, Huimin; Zhang, Shi; Liu, Quanhui; Duan, Huigao
2017-06-01
The coupled asymmetric plasmonic nanostructures allow more compact nanophotonics integration and easier optical control in practical applications, such as directional scattering and near-field control. Here, we carried out a systematic and in-depth study on the plasmonic coupling of an asymmetric gold disk/sector dimer, and investigated the light-matter interaction in such an asymmetric coupled complex nanostructures. The results demonstrated that the positions and the intensity of plasmon resonance peak as well as the spatial distribution of electric fields around the surface in the coupled disk/sector dimer can be tuned by changing the azimuth angle of the gold sector. Based on Simpson-Peterson approximation, we proposed a model to understand the obtained plasmon properties of asymmetric coupled disk/sector dimers by introducing an offset parameter between the geometry center and dipole center of the sector. The experimental results agree well with the simulations. Our study provides an insight to tune the plasmon coupling behavior via adjusting the plasmon dipole center position in coupling systems.
Leptogenesis scenarios for natural SUSY with mixed axion-higgsino dark matter
NASA Astrophysics Data System (ADS)
Bae, Kyu Jung; Baer, Howard; Serce, Hasan; Zhang, Yi-Fan
2016-01-01
Supersymmetric models with radiatively-driven electroweak naturalness require light higgsinos of mass ~ 100-300 GeV . Naturalness in the QCD sector is invoked via the Peccei-Quinn (PQ) axion leading to mixed axion-higgsino dark matter. The SUSY DFSZ axion model provides a solution to the SUSY μ problem and the Little Hierarchy μll m3/2 may emerge as a consequence of a mismatch between PQ and hidden sector mass scales. The traditional gravitino problem is now augmented by the axino and saxion problems, since these latter particles can also contribute to overproduction of WIMPs or dark radiation, or violation of BBN constraints. We compute regions of the TR vs. m3/2 plane allowed by BBN, dark matter and dark radiation constraints for various PQ scale choices fa. These regions are compared to the values needed for thermal leptogenesis, non-thermal leptogenesis, oscillating sneutrino leptogenesis and Affleck-Dine leptogenesis. The latter three are allowed in wide regions of parameter space for PQ scale fa~ 1010-1012 GeV which is also favored by naturalness: fa ~ √μMP/λμ ~ 1010-1012 GeV . These fa values correspond to axion masses somewhat above the projected ADMX search regions.
Tetraquark operators in lattice QCD and exotic flavour states in the charm sector
Cheung, Gavin K. C.; Thomas, Christopher E.; Dudek, Jozef J.; ...
2017-11-08
We present a general class of operators resembling compact tetraquarks which have a range of colour-flavour-spin structures, transform irreducibly under the symmetries of the lattice and respect other relevant symmetries. These constructions are demonstrated in lattice QCD calculations with light quarks corresponding to m π = 391 MeV. Using the distillation framework, correlation functions involving large bases of meson-meson and tetraquark operators are computed in the isospin-1 hidden-charm and doubly-charmed sectors, and finite-volume spectra are extracted with the variational method. We find the spectra are insensitive to the addition of tetraquark operators to the bases of meson-meson operators. For themore » first time, through using diverse bases of meson-meson operators, the multiple energy levels associated with meson-meson levels which would be degenerate in the non-interacting limit are extracted reliably. The number of energy levels in each spectrum is found to be equal to the number of expected non-interacting meson-meson levels in the energy region considered and the majority of energies lie close to the non-interacting levels. Furthermore, there is no strong indication for any bound state or narrow resonance in the channels we study.« less
Tetraquark operators in lattice QCD and exotic flavour states in the charm sector
NASA Astrophysics Data System (ADS)
Cheung, Gavin K. C.; Thomas, Christopher E.; Dudek, Jozef J.; Edwards, Robert G.
2017-11-01
We present a general class of operators resembling compact tetraquarks which have a range of colour-flavour-spin structures, transform irreducibly under the symmetries of the lattice and respect other relevant symmetries. These constructions are demonstrated in lattice QCD calculations with light quarks corresponding to m π = 391 MeV. Using the distillation framework, correlation functions involving large bases of meson-meson and tetraquark operators are computed in the isospin-1 hidden-charm and doubly-charmed sectors, and finite-volume spectra are extracted with the variational method. We find the spectra are insensitive to the addition of tetraquark operators to the bases of meson-meson operators. For the first time, through using diverse bases of meson-meson operators, the multiple energy levels associated with meson-meson levels which would be degenerate in the non-interacting limit are extracted reliably. The number of energy levels in each spectrum is found to be equal to the number of expected non-interacting meson-meson levels in the energy region considered and the majority of energies lie close to the non-interacting levels. Therefore, there is no strong indication for any bound state or narrow resonance in the channels we study.
Dark forces in the sky: signals from Z{sup ′} and the dark Higgs
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bell, Nicole F.; Cai, Yi; Leane, Rebecca K.
2016-08-01
We consider the indirect detection signals for a self-consistent hidden U(1) model containing a Majorana dark matter candidate, χ, a dark gauge boson, Z{sup ′}, and a dark Higgs, s. Compared with a model containing only a dark matter candidate and Z{sup ′} mediator, the addition of the scalar provides a mass generation mechanism for the dark sector particles and is required in order to avoid unitarity violation at high energies. We find that the inclusion of the two mediators opens up a new two-body s-wave annihilation channel, χχ→sZ{sup ′}. This new process, which is missed in the usual single-mediatormore » simplified model approach, can be the dominant annihilation channel. This provides rich phenomenology for indirect detection searches, allows indirect searches to explore regions of parameter space not accessible with other commonly considered s-wave annihilation processes, and enables both the Z{sup ′} and scalar couplings to be probed. We examine the phenomenology of the sector with a focus on this new process, and determine the limits on the model parameter space from Fermi data on dwarf spheriodal galaxies and other relevant experiments.« less
Positively deflected anomaly mediation in the light of the Higgs boson discovery
NASA Astrophysics Data System (ADS)
Okada, Nobuchika; Tran, Hieu Minh
2013-02-01
Anomaly-mediated supersymmetry breaking (AMSB) is a well-known mechanism for flavor-blind transmission of supersymmetry breaking from the hidden sector to the visible sector. However, the pure AMSB scenario suffers from a serious drawback, namely, the tachyonic slepton problem, and needs to be extended. The so-called (positively) deflected AMSB is a simple extension to solve the problem and also provides us with the usual neutralino lightest superpartner as a good candidate for dark matter in the Universe. Motivated by the recent discovery of the Higgs boson at the Large Hadron Collider (LHC) experiments, we perform the parameter scan in the deflected AMSB scenario by taking into account a variety of phenomenological constraints, such as the dark matter relic density and the observed Higgs boson mass around 125-126 GeV. We identify the allowed parameter region and list benchmark mass spectra. We find that in most of the allowed parameter regions, the dark matter neutralino is Higgsino-like and its elastic scattering cross section with nuclei is within the future reach of the direct dark matter search experiments, while (colored) sparticles are quite heavy and their discovery at the LHC is challenging.
The Commercial Energy Consumer: About Whom Are We Speaking?
DOE Office of Scientific and Technical Information (OSTI.GOV)
Payne, Christopher
2006-05-12
Who are commercial sector customers, and how do they make decisions about energy consumption and energy efficiency investment? The energy policy field has not done a thorough job of describing energy consumption in the commercial sector. First, the discussion of the commercial sector itself is dominated by discussion of large businesses/buildings. Second, discussion of this portion of the commercial sectors consumption behavior is driven primarily by theory, with very little field data collected on the way commercial sector decision-makers describe their own options, choices, and reasons for taking action. These limitations artificially constrain energy policy options. This paper reviews themore » extant literature on commercial sector energy consumption behavior and identifies gaps in our knowledge. In particular, it argues that the primary energy policy model of commercial sector energy consumption is a top-down model that uses macro-level investment data to make conclusions about commercial behavior. Missing from the discussion is a model of consumption behavior that builds up to a theoretical framework informed by the micro-level data provided by commercial decision-makers themselves. Such a bottom-up model could enhance the effectiveness of commercial sector energy policy. In particular, translation of some behavioral models from the residential sector to the commercial sector may offer new opportunities for policies to change commercial energy consumption behavior. Utility bill consumption feedback is considered as one example of a policy option that may be applicable to both the residential and small commercial sector.« less
Labor Market Leverage. Sectoral Employment Field Report.
ERIC Educational Resources Information Center
Elliott, Mark; King, Elisabeth
This document explains the concept of sectoral employment strategies and profiles 13 successful work force development programs based on such strategies. The first half of the document examines the increasing need for sectoral employment strategies and their key characteristics, role in achieving systemic change in work organizations, and…
The topology of intrasector reversals of the interplanetary magnetic field
NASA Astrophysics Data System (ADS)
Kahler, S. W.; Crooker, N. U.; Gosling, J. T.
1996-11-01
A technique has been developed recently to determine the polarities of interplanetary magnetic fields relative to their origins at the Sun by comparing energetic electron flow directions with local magnetic field directions. Here we use heat flux electrons from the Los Alamos National Laboratory (LANL) plasma detector on the ISEE 3 spacecraft to determine the field polarities. We examine periods within well-defined magnetic sectors when the field directions appear to be reversed from the normal spiral direction of the sector. About half of these intrasector field reversals (IFRs) are cases in which the polarities match those of the surrounding sectors, indicating that those fields have been folded back toward the Sun. The more interesting cases are those with polarity reversals. We find no clear cases of isolated reverse polarity fields, which suggests that islands of reverse polarity in the solar source dipole field probably do not exist. The IFRs with polarity reversals are strongly associated with periods of bidirectional electron flows, suggesting that those fields occur only in conjunction with closed fields. We propose that both those IFRs and the bidirectional flows are signatures of coronal mass ejections (CMEs). In that case, many interplanetary CMEs are larger and more complex than previously thought, consisting of both open and closed field components.
Adventures in heterotic string phenomenology
NASA Astrophysics Data System (ADS)
Dundee, George Benjamin
In this Dissertation, we consider three topics in the study of effective field theories derived from orbifold compactifications of the heterotic string. In Chapter 2 we provide a primer for those interested in building models based on orbifold compactifications of the heterotic string. In Chapter 3, we analyze gauge coupling unification in the context of heterotic strings on anisotropic orbifolds. This construction is very much analogous to effective five dimensional orbifold GUT field theories. Our analysis assumes three fundamental scales, the string scale, M S, a compactification scale, MC, and a mass scale for some of the vector-like exotics, MEX; the other exotics are assumed to get mass at MS. In the particular models analyzed, we show that gauge coupling unification is not possible with MEX = M C and in fact we require MEX << MC ˜ 3 x 1016 GeV. We find that about 10% of the parameter space has a proton lifetime (from dimension six gauge exchange) 1033 yr ≲ tau(p → pi0e+) ≲ 1036 yr, which is potentially observable by the next generation of proton decay experiments. 80% of the parameter space gives proton lifetimes below Super-K bounds. In Chapter 4, we examine the relationship between the string coupling constant, gSTRING, and the grand unified gauge coupling constant, alphaGUT, in the models of Chapter 3. We find that the requirement that the theory be perturbative provides a non-trivial constraint on these models. Interestingly, there is a correlation between the proton decay rate (due to dimension six operators) and the string coupling constant in this class of models. Finally, we make some comments concerning the extension of these models to the six (and higher) dimensional case. In Chapter 5, we discuss the issues of supersymmetry breaking and moduli stabilization within the context of E8 ⊗ E8 heterotic orbifold constructions and, in particular, we focus on the class of "mini-landscape" models. These theories contain a non-Abelian hidden gauge sector which generates a non-perturbative superpotential leading to supersymmetry breaking and moduli stabilization. We demonstrate this effect in a simple model which contains many of the features of the more general construction. In addition, we argue that once supersymmetry is broken in a restricted sector of the theory, then all moduli are stabilized by supergravity effects. Finally, we obtain the low energy superparticle spectrum resulting from this simple model.
Exposing Hidden Relations: Storytelling, Pedagogy, and the Study of Policy
ERIC Educational Resources Information Center
Moore, Kristen
2013-01-01
Within a Technical Communication classroom, policywork has been used to teach students the vital discursive and conceptual skills valued by technical fields. However, given the move of technical communicators into the public sphere, these skills can and should be expanded to include diverse practices and modes of thought. As such, this article…
The Hidden Profession of Histotechnology
ERIC Educational Resources Information Center
Gibbs, Hope J.
2004-01-01
Today there are more job openings in the field of histotechnology than there are educated people to fill them, and the U.S. Department of Labor expects employment opportunities for histotechnicians and histotechnologists to grow by 10 to 20 percent over the next eight years. According to the Wage and Vacancy Survey published by the American…
Efficiently Exploring Multilevel Data with Recursive Partitioning
ERIC Educational Resources Information Center
Martin, Daniel P.; von Oertzen, Timo; Rimm-Kaufman, Sara E.
2015-01-01
There is an increasing number of datasets with many participants, variables, or both, in education and other fields that often deal with large, multilevel data structures. Once initial confirmatory hypotheses are exhausted, it can be difficult to determine how best to explore the dataset to discover hidden relationships that could help to inform…
Seed size- and density-related hidden treatments in common biodiversity experiments
Qinfeng Guo
2011-01-01
With a few exceptions, most well-known field biodiversity experiments on ecosystem functioning have been conducted in plant communities (especially grasslands) in which different numbers of species are planted as treatments. In these experiments, investigators have either kept the total seed weight or seed number constant across treatment plots. However, although in...
Journal of Undergraduate Psychological Research, Vol. 1, No. 1.
ERIC Educational Resources Information Center
Ladd, Sandra L., Ed.; Hughmanick, Michael, Ed.
1974-01-01
Articles resulting from studies conducted by college undergraduates in all areas of experimental psychology are provided, together with abstracts of other papers authored by students in the field of study. The articles are: The Influence of SET on Solving Hidden-Word Problems by Lana I. Boutacoff; Violation of Personal Space in Deviant Adolescents…
Use of electroreception during foraging by the Australian lungfish.
Watt; Evans; Joss
1999-11-01
A diverse range of animals, including elasmobranchs and nonteleost fish, use passive electroreception to locate hidden prey. The Australian lungfish, Neoceratodus forsteri (Krefft 1870), has ampullary organs analogous in form to the electroreceptors of other nonteleost fish. Afferents from these ampullae project to regions in the brain that are known to process electrosensory information in other species, suggesting that N. forsteri possesses an electric sense that may be used during prey location. To explore this hypothesis directly, we first characterized food-locating behaviour in N. forsteri and then conducted an experiment designed to quantify the effects of manipulating electrical and olfactory stimuli from live prey. A small crayfish, Cherax destructor, was housed in a specially constructed chamber hidden beneath the substrate, which prevented emission of chemical, mechanical and visual cues, but allowed transmission of bioelectric fields. Control treatments included presentation of electrically shielded prey, a dead crayfish and an empty chamber. In some treatments, a competing olfactory signal was presented simultaneously at the other end of the test tank to assess the relative salience of this sensory modality. The lungfish responded to the crayfish in the unshielded chamber with accurate and sustained feeding movements, even with a competing olfactory signal. By contrast, the abolition of electrical cues in the three control treatments reduced the accuracy and frequency of feeding movements in the vicinity of the target chamber. These results show that N. forsteri is capable of perceiving the weak electric fields surrounding living animals, and suggest that it uses this information when foraging to locate prey hidden from view. Copyright 1999 The Association for the Study of Animal Behaviour.
A substantial amount of hidden magnetic energy in the quiet Sun.
Bueno, J Trujillo; Shchukina, N; Ramos, A Asensio
2004-07-15
Deciphering and understanding the small-scale magnetic activity of the quiet solar photosphere should help to solve many of the key problems of solar and stellar physics, such as the magnetic coupling to the outer atmosphere and the coronal heating. At present, we can see only approximately 1 per cent of the complex magnetism of the quiet Sun, which highlights the need to develop a reliable way to investigate the remaining 99 per cent. Here we report three-dimensional radiative transfer modelling of scattering polarization in atomic and molecular lines that indicates the presence of hidden, mixed-polarity fields on subresolution scales. Combining this modelling with recent observational data, we find a ubiquitous tangled magnetic field with an average strength of approximately 130 G, which is much stronger in the intergranular regions of solar surface convection than in the granular regions. So the average magnetic energy density in the quiet solar photosphere is at least two orders of magnitude greater than that derived from simplistic one-dimensional investigations, and sufficient to balance radiative energy losses from the solar chromosphere.
Curriculum Documents and Practice in the NZ Polytechnic Sector: Consensus and Dissensus
ERIC Educational Resources Information Center
Melles, Gavin
2008-01-01
In New Zealand the polytechnic sector embraces a range of post-compulsory education fields. Fields as diverse as nursing, business, social work and English as a Second Language (ESL) may co-exist on polytechnic campuses and are subject to similar curriculum documentation processes. The common competency-based framework and discourse of such…
Zare Hosseini, Zeinab; Mohammadzadeh, Mahdi
2016-01-01
The rapid growing of information technology (IT) motivates and makes competitive advantages in health care industry. Nowadays, many hospitals try to build a successful customer relationship management (CRM) to recognize target and potential patients, increase patient loyalty and satisfaction and finally maximize their profitability. Many hospitals have large data warehouses containing customer demographic and transactions information. Data mining techniques can be used to analyze this data and discover hidden knowledge of customers. This research develops an extended RFM model, namely RFML (added parameter: Length) based on health care services for a public sector hospital in Iran with the idea that there is contrast between patient and customer loyalty, to estimate customer life time value (CLV) for each patient. We used Two-step and K-means algorithms as clustering methods and Decision tree (CHAID) as classification technique to segment the patients to find out target, potential and loyal customers in order to implement strengthen CRM. Two approaches are used for classification: first, the result of clustering is considered as Decision attribute in classification process and second, the result of segmentation based on CLV value of patients (estimated by RFML) is considered as Decision attribute. Finally the results of CHAID algorithm show the significant hidden rules and identify existing patterns of hospital consumers.
Zare Hosseini, Zeinab; Mohammadzadeh, Mahdi
2016-01-01
The rapid growing of information technology (IT) motivates and makes competitive advantages in health care industry. Nowadays, many hospitals try to build a successful customer relationship management (CRM) to recognize target and potential patients, increase patient loyalty and satisfaction and finally maximize their profitability. Many hospitals have large data warehouses containing customer demographic and transactions information. Data mining techniques can be used to analyze this data and discover hidden knowledge of customers. This research develops an extended RFM model, namely RFML (added parameter: Length) based on health care services for a public sector hospital in Iran with the idea that there is contrast between patient and customer loyalty, to estimate customer life time value (CLV) for each patient. We used Two-step and K-means algorithms as clustering methods and Decision tree (CHAID) as classification technique to segment the patients to find out target, potential and loyal customers in order to implement strengthen CRM. Two approaches are used for classification: first, the result of clustering is considered as Decision attribute in classification process and second, the result of segmentation based on CLV value of patients (estimated by RFML) is considered as Decision attribute. Finally the results of CHAID algorithm show the significant hidden rules and identify existing patterns of hospital consumers. PMID:27610177
NASA Astrophysics Data System (ADS)
Hattori, T.; Sakai, H.; Tokunaga, Y.; Kambe, S.; Matsuda, T. D.; Haga, Y.
2018-01-01
In order to identify the spin contribution to superconducting pairing compatible with the so-called "hidden order",
Li, Yong; Jing, Haoqing; Zainal Abidin, Ilham Mukriz; Yan, Bei
2017-01-01
Coated conductive structures are widely adopted in such engineering fields as aerospace, nuclear energy, etc. The hostile and corrosive environment leaves in-service coated conductive structures vulnerable to Hidden Material Degradation (HMD) occurring under the protection coating. It is highly demanded that HMD can be non-intrusively assessed using non-destructive evaluation techniques. In light of the advantages of Gradient-field Pulsed Eddy Current technique (GPEC) over other non-destructive evaluation methods in corrosion evaluation, in this paper the GPEC probe for quantitative evaluation of HMD is intensively investigated. Closed-form expressions of GPEC responses to HMD are formulated via analytical modeling. The Lift-off Invariance (LOI) in GPEC signals, which makes the HMD evaluation immune to the variation in thickness of the protection coating, is introduced and analyzed through simulations involving HMD with variable depths and conductivities. A fast inverse method employing magnitude and time of the LOI point in GPEC signals for simultaneously evaluating the conductivity and thickness of HMD region is proposed, and subsequently verified by finite element modeling and experiments. It has been found from the results that along with the proposed inverse method the GPEC probe is applicable to evaluation of HMD in coated conductive structures without much loss in accuracy. PMID:28441328
Task complexity modifies the search strategy of rats.
Ruprecht, Chad M; Taylor, C Drew; Wolf, Joshua E; Leising, Kenneth J
2014-01-01
Human and non-human animals exhibit a variety of response strategies (e.g., place responding) when searching for a familiar place or evading predators. We still know little about the conditions that support the use of each strategy. We trained rats to locate a hidden food reward in a small-scale spatial search task. The complexity of the search task was manipulated by reducing the number of search locations (25, 4, and 2) within an open-field apparatus and by comparison to a path-based apparatus (plus-maze). After rats were trained to reliably locate the hidden food, each apparatus was shifted to gauge whether rats were searching at the location of the goal relative to extramaze cues (i.e., place responding), or searching in the direction of the goal relative to a combination of intramaze and extramaze cues (i.e.,directional responding). The results indicate that the open field supported place responding when more than two response locations were present, whereas, the four-arm plus-maze supported strong directional responding. These results extend prior research into the role of task demands on search strategy, as well as support the use of the four-choice open field as an analog to the Morris water task for future studies targeting the neural underpinnings of place responding.
Li, Yong; Jing, Haoqing; Zainal Abidin, Ilham Mukriz; Yan, Bei
2017-04-25
Coated conductive structures are widely adopted in such engineering fields as aerospace, nuclear energy, etc. The hostile and corrosive environment leaves in-service coated conductive structures vulnerable to Hidden Material Degradation (HMD) occurring under the protection coating. It is highly demanded that HMD can be non-intrusively assessed using non-destructive evaluation techniques. In light of the advantages of Gradient-field Pulsed Eddy Current technique (GPEC) over other non-destructive evaluation methods in corrosion evaluation, in this paper the GPEC probe for quantitative evaluation of HMD is intensively investigated. Closed-form expressions of GPEC responses to HMD are formulated via analytical modeling. The Lift-off Invariance (LOI) in GPEC signals, which makes the HMD evaluation immune to the variation in thickness of the protection coating, is introduced and analyzed through simulations involving HMD with variable depths and conductivities. A fast inverse method employing magnitude and time of the LOI point in GPEC signals for simultaneously evaluating the conductivity and thickness of HMD region is proposed, and subsequently verified by finite element modeling and experiments. It has been found from the results that along with the proposed inverse method the GPEC probe is applicable to evaluation of HMD in coated conductive structures without much loss in accuracy.
The sun's magnetic sector structure
NASA Technical Reports Server (NTRS)
Svalgaard, L.; Wilcox, J. M.; Scherrer, P. H.; Howard, R.
1975-01-01
The synoptic appearance of solar magnetic sectors is studied using 454 sector boundaries observed at earth during 1959-1973. The sectors are clearly visible in the photospheric magnetic field. Sector boundaries can be clearly identified as north-south running demarcation lines between regions of persistent magnetic polarity imbalances. These regions extend up to about 35 deg of latitude on both sides of the equator. They generally do not extend into the polar caps. The polar cap boundary can be identified as an east-west demarcation line marking the poleward limit of the sectors. The typical flux imbalance for a magnetic sector is about 4 x 10 to the 21st power Maxwells.
A search for pair production of new light bosons decaying into muons
NASA Astrophysics Data System (ADS)
Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Knünz, V.; König, A.; Krammer, M.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; Ochesanu, S.; Rougny, R.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; De Bruyn, I.; Deroover, K.; Heracleous, N.; Keaveney, J.; Lowette, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Van Parijs, I.; Barria, P.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Delannoy, H.; Dobur, D.; Fasanella, G.; Favart, L.; Gay, A. P. R.; Grebenyuk, A.; Lenzi, T.; Léonard, A.; Maerschalk, T.; Mohammadi, A.; Perniè, L.; Randle-conde, A.; Reis, T.; Seva, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Zenoni, F.; Zhang, F.; Beernaert, K.; Benucci, L.; Cimmino, A.; Crucy, S.; Fagot, A.; Garcia, G.; Gul, M.; Mccartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva Diblen, S.; Sigamani, M.; Strobbe, N.; Tytgat, M.; Van Driessche, W.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bondu, O.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; Da Silveira, G. G.; Delaere, C.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Mertens, A.; Nuttens, C.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Beliy, N.; Caebergs, T.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Dos Reis Martins, T.; Hensel, C.; Mora Herrera, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; De Souza Santos, A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Genchev, V.; Hadjiiska, R.; Iaydjiev, P.; Marinov, A.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Plestina, R.; Romeo, F.; Shaheen, S. M.; Tao, J.; Wang, C.; Wang, Z.; Zhang, H.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Zou, W.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Bodlak, M.; Finger, M.; Finger, M.; Ali, A.; Aly, R.; Aly, S.; Assran, Y.; Ellithi Kamel, A.; Kuotb Awad, A. M.; Lotfy, A.; Masod, R.; Radi, A.; Calpas, B.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Pekkanen, J.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Dahms, T.; Davignon, O.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Lisniak, S.; Mastrolorenzo, L.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Merlin, J. A.; Skovpen, K.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Bernet, C.; Boudoul, G.; Bouvier, E.; Brochet, S.; Carrillo Montoya, C. A.; Chasserat, J.; Chierici, R.; Contardo, D.; Courbon, B.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Laktineh, I. B.; Lethuillier, M.; Mirabito, L.; Pequegnot, A. L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Xiao, H.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Edelhoff, M.; Feld, L.; Heister, A.; Kiesel, M. K.; Klein, K.; Lipinski, M.; Ostapchuk, A.; Preuten, M.; Raupach, F.; Sammet, J.; Schael, S.; Schulte, J. F.; Verlage, T.; Weber, H.; Wittmer, B.; Zhukov, V.; Ata, M.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Endres, M.; Erdmann, M.; Erdweg, S.; Esch, T.; Fischer, R.; Güth, A.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Klingebiel, D.; Knutzen, S.; Kreuzer, P.; Merschmeyer, M.; Meyer, A.; Millet, P.; Olschewski, M.; Padeken, K.; Papacz, P.; Pook, T.; Radziej, M.; Reithler, H.; Rieger, M.; Scheuch, F.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Cherepanov, V.; Erdogan, Y.; Flügge, G.; Geenen, H.; Geisler, M.; Haj Ahmad, W.; Hoehle, F.; Kargoll, B.; Kress, T.; Kuessel, Y.; Künsken, A.; Lingemann, J.; Nehrkorn, A.; Nowack, A.; Nugent, I. M.; Pistone, C.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Asin, I.; Bartosik, N.; Behnke, O.; Behrens, U.; Bell, A. J.; Borras, K.; Burgmeier, A.; Cakir, A.; Calligaris, L.; Campbell, A.; Choudhury, S.; Costanza, F.; Diez Pardos, C.; Dolinska, G.; Dooling, S.; Dorland, T.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Flucke, G.; Gallo, E.; Garay Garcia, J.; Geiser, A.; Gizhko, A.; Gunnellini, P.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Karacheban, O.; Kasemann, M.; Katsas, P.; Kieseler, J.; Kleinwort, C.; Korol, I.; Lange, W.; Leonard, J.; Lipka, K.; Lobanov, A.; Lohmann, W.; Mankel, R.; Marfin, I.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Naumann-Emme, S.; Nayak, A.; Ntomari, E.; Perrey, H.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Ribeiro Cipriano, P. M.; Roland, B.; Sahin, M. Ö.; Salfeld-Nebgen, J.; Saxena, P.; Schoerner-Sadenius, T.; Schröder, M.; Seitz, C.; Spannagel, S.; Trippkewitz, K. D.; Wissing, C.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Erfle, J.; Garutti, E.; Goebel, K.; Gonzalez, D.; Görner, M.; Haller, J.; Hoffmann, M.; Höing, R. S.; Junkes, A.; Klanner, R.; Kogler, R.; Lapsien, T.; Lenz, T.; Marchesini, I.; Marconi, D.; Nowatschin, D.; Ott, J.; Pantaleo, F.; Peiffer, T.; Perieanu, A.; Pietsch, N.; Poehlsen, J.; Rathjens, D.; Sander, C.; Schettler, H.; Schleper, P.; Schlieckau, E.; Schmidt, A.; Schwandt, J.; Seidel, M.; Sola, V.; Stadie, H.; Steinbrück, G.; Tholen, H.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Akbiyik, M.; Barth, C.; Baus, C.; Berger, J.; Böser, C.; Butz, E.; Chwalek, T.; Colombo, F.; De Boer, W.; Descroix, A.; Dierlamm, A.; Feindt, M.; Frensch, F.; Giffels, M.; Gilbert, A.; Hartmann, F.; Husemann, U.; Kassel, F.; Katkov, I.; Kornmayer, A.; Lobelle Pardo, P.; Mozer, M. U.; Müller, T.; Müller, Th.; Plagge, M.; Quast, G.; Rabbertz, K.; Röcker, S.; Roscher, F.; Simonis, H. J.; Stober, F. M.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weiler, T.; Wöhrmann, C.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Markou, A.; Psallidas, A.; Topsis-Giotis, I.; Agapitos, A.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Tziaferi, E.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Loukas, N.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Strologas, J.; Bencze, G.; Hajdu, C.; Hazi, A.; Hidas, P.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Molnar, J.; Szillasi, Z.; Bartók, M.; Makovec, A.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Mal, P.; Mandal, K.; Sahoo, N.; Swain, S. K.; Bansal, S.; Beri, S. B.; Bhatnagar, V.; Chawla, R.; Gupta, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, A.; Kaur, M.; Kumar, R.; Mehta, A.; Mittal, M.; Nishu, N.; Singh, J. B.; Walia, G.; Kumar, Ashok; Kumar, Arun; Bhardwaj, A.; Choudhary, B. C.; Garg, R. B.; Kumar, A.; Malhotra, S.; Naimuddin, M.; Ranjan, K.; Sharma, R.; Sharma, V.; Banerjee, S.; Bhattacharya, S.; Chatterjee, K.; Dey, S.; Dutta, S.; Jain, Sa.; Jain, Sh.; Khurana, R.; Majumdar, N.; Modak, A.; Mondal, K.; Mukherjee, S.; Mukhopadhyay, S.; Roy, A.; Roy, D.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Abdulsalam, A.; Chudasama, R.; Dutta, D.; Jha, V.; Kumar, V.; Mohanty, A. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Banerjee, S.; Bhowmik, S.; Chatterjee, R. M.; Dewanjee, R. K.; Dugad, S.; Ganguly, S.; Ghosh, S.; Guchait, M.; Gurtu, A.; Kole, G.; Kumar, S.; Mahakud, B.; Maity, M.; Majumder, G.; Mazumdar, K.; Mitra, S.; Mohanty, G. B.; Parida, B.; Sarkar, T.; Sudhakar, K.; Sur, N.; Sutar, B.; Wickramage, N.; Sharma, S.; Bakhshiansohi, H.; Behnamian, H.; Etesami, S. M.; Fahim, A.; Goldouzian, R.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Caputo, C.; Chhibra, S. S.; Colaleo, A.; Creanza, D.; Cristella, L.; De Filippis, N.; De Palma, M.; Fiore, L.; Iaselli, G.; Maggi, G.; Maggi, M.; Miniello, G.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Ranieri, A.; Selvaggi, G.; Sharma, A.; Silvestris, L.; Venditti, R.; Verwilligen, P.; Abbiendi, G.; Battilana, C.; Benvenuti, A. C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Rovelli, T.; Siroli, G. P.; Tosi, N.; Travaglini, R.; Cappello, G.; Chiorboli, M.; Costa, S.; Giordano, F.; Potenza, R.; Tricomi, A.; Tuve, C.; Barbagli, G.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Gonzi, S.; Gori, V.; Lenzi, P.; Meschini, M.; Paoletti, S.; Sguazzoni, G.; Tropiano, A.; Viliani, L.; Benussi, L.; Bianco, S.; Fabbri, F.; Piccolo, D.; Calvelli, V.; Ferro, F.; Lo Vetere, M.; Robutti, E.; Tosi, S.; Dinardo, M. E.; Fiorendi, S.; Gennai, S.; Gerosa, R.; Ghezzi, A.; Govoni, P.; Malvezzi, S.; Manzoni, R. A.; Marzocchi, B.; Menasce, D.; Moroni, L.; Paganoni, M.; Pedrini, D.; Ragazzi, S.; Redaelli, N.; Tabarelli de Fatis, T.; Buontempo, S.; Cavallo, N.; Di Guida, S.; Esposito, M.; Fabozzi, F.; Iorio, A. O. M.; Lanza, G.; Lista, L.; Meola, S.; Merola, M.; Paolucci, P.; Sciacca, C.; Thyssen, F.; Azzi, P.; Bacchetta, N.; Bisello, D.; Carlin, R.; Carvalho Antunes De Oliveira, A.; Checchia, P.; Dall'Osso, M.; Dorigo, T.; Dosselli, U.; Gasparini, F.; Gasparini, U.; Gozzelino, A.; Lacaprara, S.; Margoni, M.; Meneguzzo, A. T.; Pazzini, J.; Pegoraro, M.; Pozzobon, N.; Ronchese, P.; Simonetto, F.; Torassa, E.; Tosi, M.; Vanini, S.; Zanetti, M.; Zotto, P.; Zucchetta, A.; Zumerle, G.; Braghieri, A.; Gabusi, M.; Magnani, A.; Ratti, S. P.; Re, V.; Riccardi, C.; Salvini, P.; Vai, I.; Vitulo, P.; Alunni Solestizi, L.; Biasini, M.; Bilei, G. M.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Mantovani, G.; Menichelli, M.; Saha, A.; Santocchia, A.; Spiezia, A.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bernardini, J.; Boccali, T.; Broccolo, G.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Donato, S.; Fedi, G.; Foà, L.; Giassi, A.; Grippo, M. T.; Ligabue, F.; Lomtadze, T.; Martini, L.; Messineo, A.; Palla, F.; Rizzi, A.; Savoy-Navarro, A.; Serban, A. T.; Spagnolo, P.; Squillacioti, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. G.; Barone, L.; Cavallari, F.; D'imperio, G.; Del Re, D.; Diemoz, M.; Gelli, S.; Jorda, C.; Longo, E.; Margaroli, F.; Meridiani, P.; Micheli, F.; Organtini, G.; Paramatti, R.; Preiato, F.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Soffi, L.; Traczyk, P.; Amapane, N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bellan, R.; Biino, C.; Cartiglia, N.; Costa, M.; Covarelli, R.; Dattola, D.; Degano, A.; Demaria, N.; Finco, L.; Mariotti, C.; Maselli, S.; Migliore, E.; Monaco, V.; Monteil, E.; Musich, M.; Obertino, M. M.; Pacher, L.; Pastrone, N.; Pelliccioni, M.; Pinna Angioni, G. L.; Ravera, F.; Romero, A.; Ruspa, M.; Sacchi, R.; Solano, A.; Staiano, A.; Tamponi, U.; Belforte, S.; Candelise, V.; Casarsa, M.; Cossutti, F.; Della Ricca, G.; Gobbo, B.; La Licata, C.; Marone, M.; Schizzi, A.; Umer, T.; Zanetti, A.; Chang, S.; Kropivnitskaya, A.; Nam, S. K.; Kim, D. H.; Kim, G. N.; Kim, M. S.; Kong, D. J.; Lee, S.; Oh, Y. D.; Sakharov, A.; Son, D. C.; Kim, H.; Kim, T. J.; Ryu, M. S.; Song, S.; Choi, S.; Go, Y.; Gyun, D.; Hong, B.; Jo, M.; Kim, H.; Kim, Y.; Lee, B.; Lee, K.; Lee, K. S.; Lee, S.; Park, S. K.; Roh, Y.; Yoo, H. D.; Choi, M.; Kim, J. H.; Lee, J. S. H.; Park, I. C.; Ryu, G.; Choi, Y.; Choi, Y. K.; Goh, J.; Kim, D.; Kwon, E.; Lee, J.; Yu, I.; Juodagalvis, A.; Vaitkus, J.; Ibrahim, Z. A.; Komaragiri, J. R.; Md Ali, M. A. B.; Mohamad Idris, F.; Wan Abdullah, W. A. 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C.; Shi, X.; Shipsey, I.; Silvers, D.; Sun, J.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Zablocki, J.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Redjimi, R.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.; Betchart, B.; Bodek, A.; de Barbaro, P.; Demina, R.; Eshaq, Y.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Goldenzweig, P.; Han, J.; Harel, A.; Hindrichs, O.; Khukhunaishvili, A.; Petrillo, G.; Verzetti, M.; Vishnevskiy, D.; Demortier, L.; Arora, S.; Barker, A.; Chou, J. P.; Contreras-Campana, C.; Contreras-Campana, E.; Duggan, D.; Ferencek, D.; Gershtein, Y.; Gray, R.; Halkiadakis, E.; Hidas, D.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Lath, A.; Panwalkar, S.; Park, M.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Foerster, M.; Riley, G.; Rose, K.; Spanier, S.; York, A.; Bouhali, O.; Castaneda Hernandez, A.; Dalchenko, M.; De Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Flanagan, W.; Gilmore, J.; Kamon, T.; Krutelyov, V.; Montalvo, R.; Mueller, R.; Osipenkov, I.; Pakhotin, Y.; Patel, R.; Perloff, A.; Roe, J.; Rose, A.; Safonov, A.; Suarez, I.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Undleeb, S.; Volobouev, I.; Appelt, E.; Delannoy, A. G.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Mao, Y.; Melo, A.; Sheldon, P.; Snook, B.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Boutle, S.; Cox, B.; Francis, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Lin, C.; Neu, C.; Wolfe, E.; Wood, J.; Xia, F.; Clarke, C.; Harr, R.; Karchin, P. E.; Kottachchi Kankanamge Don, C.; Lamichhane, P.; Sturdy, J.; Belknap, D. A.; Carlsmith, D.; Cepeda, M.; Christian, A.; Dasu, S.; Dodd, L.; Duric, S.; Friis, E.; Gomber, B.; Grothe, M.; Hall-Wilton, R.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Mohapatra, A.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ross, I.; Ruggles, T.; Sarangi, T.; Savin, A.; Smith, N.; Smith, W. H.; Taylor, D.; Woods, N.
2016-01-01
A search for the pair production of new light bosons, each decaying into a pair of muons, is performed with the CMS experiment at the LHC, using a dataset corresponding to an integrated luminosity of 20.7 fb-1 collected in proton-proton collisions at center-of-mass energy of √{ s} = 8 TeV. No excess is observed in the data relative to standard model background expectation and a model independent upper limit on the product of the cross section, branching fraction, and acceptance is derived. The results are compared with two benchmark models, the first one in the context of the next-to-minimal supersymmetric standard model, and the second one in scenarios containing a hidden sector, including those predicting a nonnegligible light boson lifetime.
An ecological approach to problems of Dark Energy, Dark Matter, MOND and Neutrinos
NASA Astrophysics Data System (ADS)
Zhao, Hong Sheng
2008-11-01
Modern astronomical data on galaxy and cosmological scales have revealed powerfully the existence of certain dark sectors of fundamental physics, i.e., existence of particles and fields outside the standard models and inaccessible by current experiments. Various approaches are taken to modify/extend the standard models. Generic theories introduce multiple de-coupled fields A, B, C, each responsible for the effects of DM (cold supersymmetric particles), DE (Dark Energy) effect, and MG (Modified Gravity) effect respectively. Some theories use adopt vanilla combinations like AB, BC, or CA, and assume A, B, C belong to decoupled sectors of physics. MOND-like MG and Cold DM are often taken as antagnising frameworks, e.g. in the muddled debate around the Bullet Cluster. Here we argue that these ad hoc divisions of sectors miss important clues from the data. The data actually suggest that the physics of all dark sectors is likely linked together by a self-interacting oscillating field, which governs a chameleon-like dark fluid, appearing as DM, DE and MG in different settings. It is timely to consider an interdisciplinary approach across all semantic boundaries of dark sectors, treating the dark stress as one identity, hence accounts for several "coincidences" naturally.
Inflation, symmetry, and B-modes
Hertzberg, Mark P.
2015-04-20
Here, we examine the role of using symmetry and effective field theory in inflationary model building. We describe the standard formulation of starting with an approximate shift symmetry for a scalar field, and then introducing corrections systematically in order to maintain control over the inflationary potential. We find that this leads to models in good agreement with recent data. On the other hand, there are attempts in the literature to deviate from this paradigm by envoking other symmetries and corrections. In particular: in a suite of recent papers, several authors have made the claim that standard Einstein gravity with amore » cosmological constant and a massless scalar carries conformal symmetry. They claim this conformal symmetry is hidden when the action is written in the Einstein frame, and so has not been fully appreciated in the literature. They further claim that such a theory carries another hidden symmetry; a global SO(1,1) symmetry. By deforming around the global SO(1,1) symmetry, they are able to produce a range of inflationary models with asymptotically flat potentials, whose flatness is claimed to be protected by these symmetries. These models tend to give rise to B-modes with small amplitude. Here we explain that standard Einstein gravity does not in fact possess conformal symmetry. Instead these authors are merely introducing a redundancy into the description, not an actual conformal symmetry. Furthermore, we explain that the only real (global) symmetry in these models is not at all hidden, but is completely manifest when expressed in the Einstein frame; it is in fact the shift symmetry of a scalar field. When analyzed systematically as an effective field theory, deformations do not generally produce asymptotically flat potentials and small B-modes as suggested in these recent papers. Instead, deforming around the shift symmetry systematically, tends to produce models of inflation with B-modes of appreciable amplitude. Such simple models typically also produce the observed red spectral index, Gaussian fluctuations, etc. In short: simple models of inflation, organized by expanding around a shift symmetry, are in excellent agreement with recent data.« less
Development and application of deep convolutional neural network in target detection
NASA Astrophysics Data System (ADS)
Jiang, Xiaowei; Wang, Chunping; Fu, Qiang
2018-04-01
With the development of big data and algorithms, deep convolution neural networks with more hidden layers have more powerful feature learning and feature expression ability than traditional machine learning methods, making artificial intelligence surpass human level in many fields. This paper first reviews the development and application of deep convolutional neural networks in the field of object detection in recent years, then briefly summarizes and ponders some existing problems in the current research, and the future development of deep convolutional neural network is prospected.
Facilitating dynamo action via control of large-scale turbulence.
Limone, A; Hatch, D R; Forest, C B; Jenko, F
2012-12-01
The magnetohydrodynamic dynamo effect is considered to be the major cause of magnetic field generation in geo- and astrophysical systems. Recent experimental and numerical results show that turbulence constitutes an obstacle to dynamos; yet its role in this context is not totally clear. Via numerical simulations, we identify large-scale turbulent vortices with a detrimental effect on the amplification of the magnetic field in a geometry of experimental interest and propose a strategy for facilitating the dynamo instability by manipulating these detrimental "hidden" dynamics.
Ferentinos, Konstantinos P
2005-09-01
Two neural network (NN) applications in the field of biological engineering are developed, designed and parameterized by an evolutionary method based on the evolutionary process of genetic algorithms. The developed systems are a fault detection NN model and a predictive modeling NN system. An indirect or 'weak specification' representation was used for the encoding of NN topologies and training parameters into genes of the genetic algorithm (GA). Some a priori knowledge of the demands in network topology for specific application cases is required by this approach, so that the infinite search space of the problem is limited to some reasonable degree. Both one-hidden-layer and two-hidden-layer network architectures were explored by the GA. Except for the network architecture, each gene of the GA also encoded the type of activation functions in both hidden and output nodes of the NN and the type of minimization algorithm that was used by the backpropagation algorithm for the training of the NN. Both models achieved satisfactory performance, while the GA system proved to be a powerful tool that can successfully replace the problematic trial-and-error approach that is usually used for these tasks.
Storm, Ilse; den Hertog, Frank; van Oers, Hans; Schuit, Albertine J
2016-06-22
The causes of health inequalities are complex. For the reduction of health inequalities, intersectoral collaboration between the public health sector and both social policy sectors (e.g. youth affairs, education) and physical policy sectors (e.g. housing, spatial planning) is essential, but in local practice difficult to realize. The aim of this study was to examine the collaboration between the sectors in question more closely and to identify opportunities for improvement. A qualitative descriptive analysis of five aspects of collaboration within sixteen Dutch municipalities was performed to examine the collaboration between the public health sector and other policy sectors: 1) involvement of the sectors in the public health policy network, 2) harmonisation of objectives, 3) use of policies by the relevant sectors, 4) formalised collaboration, and 5) previous experience. Empirical data on these collaboration aspects were collected based on document analysis, questionnaires and interviews. The study found that the policy workers of social sectors were more involved in the public health network and more frequently supported the objectives in the field of health inequality reduction. Both social policy sectors and physical policy sectors used policies and activities to reduce health inequalities. More is done to influence the determinants of health inequality through policies aimed at lifestyle and social setting than through policies aimed at socioeconomic factors and the physical environment. Where the physical policy sectors are involved in the public health network, the collaboration follows a very similar pattern as with the social policy sectors. All sectors recognise the importance of good relationships, positive experiences, a common interest in working together and coordinated mechanisms. This study shows that there is scope for improving collaboration in the field of health inequality reduction between the public health sector and both social policy sectors and physical policy sectors. Ways in which improvement could be realised include involving physical policy sectors in the network, pursuing widely supported policy goals, making balanced efforts to influence determinants of health inequalities, and increasing the emphasis on a programmatic approach.
Poteshin, S S; Zarakovsky, A I
2017-03-15
Original orthogonal acceleration (OA) electrostatic sector time of flight (TOF) mass analyzer is proposed those allows the second order focusing of time of flight by initial ions position. Resolving power aberration limit exceeding 80,000 FW (full width mass peak) was shown to be obtainable for mass analyzer with the total length of flight L=133.2cm, the average ion energy 3700V and the ion energy spread of 2.5% on the entrance of sector field. Copyright © 2016 Elsevier B.V. All rights reserved.
NASA Technical Reports Server (NTRS)
Engebretson, M. J.; Cahill, L. J., Jr.; Winningham, J. D.; Rosenberg, T. J.; Arnoldy, R. L.; Maynard, N. C.; Sugiura, M.
1986-01-01
Ground-based magnetometer, photometer, and riometer data are combined with low-altitude particle and electric and magnetic field data from the DE-2 spacecraft to provide a more complete characterization of the magnetospheric and tropospheric environment in which morning sector asymmetric Pi 1 pulsations are observed. The results of the study are in agreement with recent conclusions that morning sector asymmetric Pi 1 pulsations are physically related to pulsating aurorae. Precipitation of energetic electrons (E greater than 35 keV) coincides in every instance with the occurrence of these pulsations.
Applications of aerospace technology in industry, a technology transfer profile: Lubrication
NASA Technical Reports Server (NTRS)
Kottenstette, J. P.; Freeman, J. E.; Heins, C. R.; Hildred, W. M.; Johnson, F. D.; Staskin, E. R.
1971-01-01
Technology transfer in the lubrication field is discussed in terms of the movement of NASA-generated lubrication technology into the private sector as affected by evolving industrial requirements. An overview of the field is presented, and NASA technical contributions to lubrication technology are described. Specific examples in which these technologies have been used in the private sector are summarized.
NASA Astrophysics Data System (ADS)
Symon, Keith R.
2005-04-01
In the late 1950's and the 1960's the MURA (Midwestern Universities Research Association) working group developed fixed field alternating gradient (FFAG) particle accelerators. FFAG accelerators are a natural corollary of the invention of alternating gradient focusing. The fixed guide field accommodates all orbits from the injection to the final energy. For this reason, the transverse motion in the guide field is nearly decoupled from the longitudinal acceleration. This allows a wide variety of acceleration schemes, using betatron or rf accelerating fields, beam stacking, bucket lifts, phase displacement, etc. It also simplifies theoretical and experimental studies of accelerators. Theoretical studies included an extensive analysis of rf acceleration processes, nonlinear orbit dynamics, and collective instabilities. Two FFAG designs, radial sector and spiral sector, were invented. The MURA team built small electron models of each type, and used them to study orbit dynamics, acceleration processes, orbit instabilities, and space charge limits. A practical result of these studies was the invention of the spiral sector cyclotron. Another was beam stacking, which led to the first practical way of achieving colliding beams. A 50 MeV two-way radial sector model was built in which it proved possible to stack a beam of over 10 amperes of electrons.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yue, Song, E-mail: yuessd@163.com; University of Chinese Academy of Sciences, Beijing 100049; Zhang, Zhao-chuan
In this paper, a sector steps approximation method is proposed to investigate the resonant frequencies of magnetrons with arbitrary side resonators. The arbitrary side resonator is substituted with a series of sector steps, in which the spatial harmonics of electromagnetic field are also considered. By using the method of admittance matching between adjacent steps, as well as field continuity conditions between side resonators and interaction regions, the dispersion equation of magnetron with arbitrary side resonators is derived. Resonant frequencies of magnetrons with five common kinds of side resonators are calculated with sector steps approximation method and computer simulation softwares, inmore » which the results have a good agreement. The relative error is less than 2%, which verifies the validity of sector steps approximation method.« less
ERIC Educational Resources Information Center
Zanskas, Stephen; Leahy, Michael
2007-01-01
As private sector rehabilitation has matured as a field of practice, the issue of how rehabilitation counselor educators can effectively prepare rehabilitation counselors for practice in this setting remains. This article reviews the literature regarding the training needs of rehabilitation counselors entering private sector practice, and proposes…
Research Frontiers in Public Sector Performance Measurement
NASA Astrophysics Data System (ADS)
Zhonghua, Cai; Ye, Wang
In "New Public Management" era, performance measurement has been widely used in managerial practices of public sectors. From the content and features of performance measurement, this paper aims to explore inspirations on Chinese public sector performance measurement, which based on a review of prior literatures including influencial factors, methods and indicators of public sector performance evaluation. In the end, arguments are presented in this paper pointed out the direction of future researches in this field.
Charting the Unknown: A Hunt in the Dark
NASA Astrophysics Data System (ADS)
Mohlabeng, Gopolang Mokoka
Astrophysical and cosmological observations have pointed strongly to the existence of dark matter in the Universe, yet its nature remains elusive. It may be hidden in a vast unknown parameter space in which exhaustively searching for a signal is not feasible. We are, therefore, compelled to consider a robust program based on a wide range of new theoretical ideas and complementary strategies for detection. The aim of this dissertation is to investigate the phenomenology of diverse dark sectors with the objective of understanding and characterizing dark matter. We do so by exploring dark matter phenomenology under three main frameworks of study: (I) the model dependent approach, (II) model independent approach and (III) considering simplified models. In each framework we focus on unexplored and well motivated dark matter scenarios as well as their prospects of detection at current and future experiments. First, we concentrate on the model dependent method where we consider minimal dark matter in the form of mixed fermionic stable states in a gauge extension of the standard model. In particular, we incorporate the fermion mixings governed by gauge invariant interactions with the heavier degrees of freedom. We find that the manner of mixing has an impact on the detectability of the dark matter at experiments. Pursuing this model dependent direction, we explore a space-time extension of the standard model which houses a vector dark matter candidate. We incorporate boundary terms arising from the topology of the model and find that these control the way dark matter may interact with baryonic matter. Next we investigate the model independent approach in which we examine a non-minimal dark sector in the form of boosted dark matter. In this study, we consider an effective field theory involving two stable fermionic states. We probe the sensitivity of this type of dark matter coming from the galactic center and the center of the Sun, and investigate its detection prospects at current and future large volume experiments. Finally, we explore an intermediate approach in the form of a simplified model. Here we analyze a different non-minimal dark sector in which its interactions with the standard model sector are mediated primarily by the Higgs Boson. We discuss for the first time a vector and fermion dark matter preserved under the same stabilization symmetry. We find that the presence of both species in the early Universe results in rare processes contributing to the dark matter relic abundance. We conclude that connecting these three frameworks under one main dark matter program, instead of concentrating on them individually, could help us understand what we are missing, and may assist us to produce ground breaking ideas which lead to the discovery of a signal in the near future.
ERIC Educational Resources Information Center
Ireland, Danyelle T.; Freeman, Kimberley Edelin; Winston-Proctor, Cynthia E.; DeLaine, Kendra D.; McDonald Lowe, Stacey; Woodson, Kamilah M.
2018-01-01
In this chapter, we argue that intersectionality is a theoretical and methodological framework by which education researchers can critically examine why and how students in STEM fields who are members of intersecting marginalized groups have distinctive experiences related to their social identities, other psychological processes, and educational…
Spatial Relational Memory in 9-Month-Old Macaque Monkeys
ERIC Educational Resources Information Center
Lavenex, Pierre; Lavenex, Pamela Banta
2006-01-01
This experiment assesses spatial and nonspatial relational memory in freely moving 9-mo-old and adult (11-13-yr-old) macaque monkeys ("Macaca mulatta"). We tested the use of proximal landmarks, two different objects placed at the center of an open-field arena, as conditional cues allowing monkeys to predict the location of food rewards hidden in…
To Teach the Holocaust in Poland: Understanding Teachers' Motivations to Engage the Painful Past
ERIC Educational Resources Information Center
Gross, Magdalena H.
2013-01-01
This article highlights the role of teachers in confronting traumatic, hidden wartime histories in communities traumatized by them. The study illuminates patterns based on field observations, emails, and surveys of 60 teachers who participated in a Holocaust teacher preparation program in Poland during the summer of 2010. The teachers surveyed…
The Expected but Well-Hidden EMF in the Jumping Wire Experiment and Its Unexpected Role
ERIC Educational Resources Information Center
Donoso, G.; Ladera, C. L.
2015-01-01
As presented in physics textbooks, as well as in a few papers, the typical example of an induced motional electromotive force e[subscript mot] = "Blv" consists of a conductive rod of length "l" frictionlessly sliding with speed v along parallel wires within an orthogonal and constant uniform magnetic field of magnitude…
ERIC Educational Resources Information Center
Hoffman, Benjamin B.
Forecasting models for maximizing postsecondary futures and applications of the model are considered. The forecasting of broad human futures has many parallels to human futures in the field of medical prognosis. The concept of "exasperated negative" is used to refer to the suppression of critical information about a negative future with…
Self-consistent Models of Strong Interaction with Chiral Symmetry
DOE R&D Accomplishments Database
Nambu, Y.; Pascual, P.
1963-04-01
Some simple models of (renormalizable) meson-nucleon interaction are examined in which the nucleon mass is entirely due to interaction and the chiral ( gamma {sub 5}) symmetry is "broken'' to become a hidden symmetry. It is found that such a scheme is possible provided that a vector meson is introduced as an elementary field. (auth)
W 4 toda example as hidden Liouville CFT
NASA Astrophysics Data System (ADS)
Furlan, P.; Petkova, V. B.
2017-03-01
We construct correlators in the W 4 Toda 2d conformal field theory for a particular class of representations and demonstrate a relation to a W 2 (Virasoro) theory with different central charge. The relevance of the classical limits of the constructed 3-point functions and braiding matrices to problems in 4d conformal theories is discussed.
The solid angle hidden in polyhedron gravitation formulations
NASA Astrophysics Data System (ADS)
Werner, Robert A.
2017-03-01
Formulas of a homogeneous polyhedron's gravitational potential typically include two arctangent terms for every edge of every face and a special term to eliminate a possible facial singularity. However, the arctangent and singularity terms are equivalent to the face's solid angle viewed from the field point. A face's solid angle can be evaluated with a single arctangent, saving computation.
Adding Spice to Vanilla LCDM simulations: Alternative Cosmologies & Lighting up Simulations
NASA Astrophysics Data System (ADS)
Jahan Elahi, Pascal
2015-08-01
Cold Dark Matter simulations have formed the backbone of our theoretical understanding of cosmological structure formation. Predictions from the Lambda Cold Dark Matter (LCDM) cosmology, where the Universe contains two dark components, namely Dark Matter & Dark Energy, are in excellent agreement with the Large-Scale Structures observed, i.e., the distribution of galaxies across cosmic time. However, this paradigm is in tension with observations at small-scales, from the number and properties of satellite galaxies around galaxies such as the Milky Way and Andromeda, to the lensing statistics of massive galaxy clusters. I will present several alternative models of cosmology (from Warm Dark Matter to coupled Dark Matter-Dark Energy models) and how they compare to vanilla LCDM by studying formation of groups and clusters dark matter only and adiabatic hydrodynamical zoom simulations. I will show how modifications to the dark sector can lead to some surprising results. For example, Warm Dark Matter, so often examined on small satellite galaxies scales, can be probed observationally using weak lensing at cluster scales. Coupled dark sectors, where dark matter decays into dark energy and experiences an effective gravitational potential that differs from that experienced by normal matter, is effectively hidden away from direct observations of galaxies. Studies like these are vital if we are to pinpoint observations which can look for unique signatures of the physics that governs the hidden Universe. Finally, I will discuss how all of these predictions are affected by uncertain galaxy formation physics. I will present results from a major comparison study of numerous hydrodynamical codes, the nIFTY cluster comparison project. This comparison aims to understand the code-to-code scatter in the properties of dark matter haloes and the galaxies that reside in them. We find that even in purely adiabatic simulations, different codes form clusters with very different X-ray profiles. The galaxies that form in these simulations, which all use codes that attempt to reproduce the observed galaxy population via not unreasonable subgrid physics, vary in stellar mass, morphology and gas fraction, sometimes by an order of magnitude. I will end with a discussion of precision cosmology in light of these results.
Hidden magnetism and quantum criticality in the heavy fermion superconductor CeRhIn5.
Park, Tuson; Ronning, F; Yuan, H Q; Salamon, M B; Movshovich, R; Sarrao, J L; Thompson, J D
2006-03-02
With only a few exceptions that are well understood, conventional superconductivity does not coexist with long-range magnetic order (for example, ref. 1). Unconventional superconductivity, on the other hand, develops near a phase boundary separating magnetically ordered and magnetically disordered phases. A maximum in the superconducting transition temperature T(c) develops where this boundary extrapolates to zero Kelvin, suggesting that fluctuations associated with this magnetic quantum-critical point are essential for unconventional superconductivity. Invariably, though, unconventional superconductivity masks the magnetic phase boundary when T < T(c), preventing proof of a magnetic quantum-critical point. Here we report specific-heat measurements of the pressure-tuned unconventional superconductor CeRhIn5 in which we find a line of quantum-phase transitions induced inside the superconducting state by an applied magnetic field. This quantum-critical line separates a phase of coexisting antiferromagnetism and superconductivity from a purely unconventional superconducting phase, and terminates at a quantum tetracritical point where the magnetic field completely suppresses superconductivity. The T --> 0 K magnetic field-pressure phase diagram of CeRhIn5 is well described with a theoretical model developed to explain field-induced magnetism in the high-T(c) copper oxides, but in which a clear delineation of quantum-phase boundaries has not been possible. These experiments establish a common relationship among hidden magnetism, quantum criticality and unconventional superconductivity in copper oxides and heavy-electron systems such as CeRhIn5.
Dark matter versus Mach's principle.
NASA Astrophysics Data System (ADS)
von Borzeszkowski, H.-H.; Treder, H.-J.
1998-02-01
Empirical and theoretical evidence show that the astrophysical problem of dark matter might be solved by a theory of Einstein-Mayer type. In this theory up to global Lorentz rotations the reference system is determined by the motion of cosmic matter. Thus one is led to a "Riemannian space with teleparallelism" realizing a geometric version of the Mach-Einstein doctrine. The field equations of this gravitational theory contain hidden matter terms where the existence of hidden matter is inferred safely from its gravitational effects. It is argued that in the nonrelativistic mechanical approximation they provide an inertia-free mechanics where the inertial mass of a body is induced by the gravitational action of the comic masses. Interpreted form the Newtonian point of view this mechanics shows that the effective gravitational mass of astrophysical objects depends on r such that one expects the existence of dark matter.
Antisymmetric Spin-Orbit Coupling in a d-p Model on a Zigzag Chain
Sugita, Yusuke; Hayami, Satoru; Motome, Yukitoshi
2015-12-29
In this paper, we theoretically investigate how an antisymmetric spin-orbit coupling emerges in electrons moving on lattice structures which are centrosymmetric but break the spatial inversion symme- try at atomic positions. We construct an effective d-p model on the simplest lattice structure, a zigzag chain of edge-sharing octahedra, with taking into account the crystalline electric field, the spin-orbit coupling, and on-site and inter-site d-p hybridizations. We show that an effective antisymmetric spin-orbit coupling arises in the sublattice-dependent form, which results in a hidden spin polarization in the band structure. Finally, we explicitly derive the effective antisymmetric spin-orbit coupling for dmore » electrons, which not only explains the hidden spin polarization but also indicates how to enhance it.« less
Antisymmetric Spin-Orbit Coupling in a d-p Model on a Zigzag Chain
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sugita, Yusuke; Hayami, Satoru; Motome, Yukitoshi
In this paper, we theoretically investigate how an antisymmetric spin-orbit coupling emerges in electrons moving on lattice structures which are centrosymmetric but break the spatial inversion symme- try at atomic positions. We construct an effective d-p model on the simplest lattice structure, a zigzag chain of edge-sharing octahedra, with taking into account the crystalline electric field, the spin-orbit coupling, and on-site and inter-site d-p hybridizations. We show that an effective antisymmetric spin-orbit coupling arises in the sublattice-dependent form, which results in a hidden spin polarization in the band structure. Finally, we explicitly derive the effective antisymmetric spin-orbit coupling for dmore » electrons, which not only explains the hidden spin polarization but also indicates how to enhance it.« less
Dark Sectors 2016 Workshop: Community Report
DOE Office of Scientific and Technical Information (OSTI.GOV)
Alexander, Jim; et al.
This report, based on the Dark Sectors workshop at SLAC in April 2016, summarizes the scientific importance of searches for dark sector dark matter and forces at masses beneath the weak-scale, the status of this broad international field, the important milestones motivating future exploration, and promising experimental opportunities to reach these milestones over the next 5-10 years.
Chameleons with field-dependent couplings
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brax, Philippe; Bruck, Carsten van de; Mota, David F.
2010-10-15
Certain scalar-tensor theories exhibit the so-called chameleon mechanism, whereby observational signatures of scalar fields are hidden by a combination of self-interactions and interactions with ambient matter. Not all scalar-tensor theories exhibit such a chameleon mechanism, which has been originally found in models with inverse power runaway potentials and field-independent couplings to matter. In this paper we investigate field theories with field-dependent couplings and a power-law potential for the scalar field. We show that the theory indeed is a chameleon field theory. We find the thin-shell solution for a spherical body and investigate the consequences for Eoet-Wash experiments, fifth-force searches andmore » Casimir-force experiments. Requiring that the scalar field evades gravitational tests, we find that the coupling is sensitive to a mass scale which is of order of the Hubble scale today.« less
Force law in material media, hidden momentum and quantum phases
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kholmetskii, Alexander L., E-mail: alkholmetskii@gmail.com; Missevitch, Oleg V.; Yarman, T.
We address to the force law in classical electrodynamics of material media, paying attention on the force term due to time variation of hidden momentum of magnetic dipoles. We highlight that the emergence of this force component is required by the general theorem, deriving zero total momentum for any static configuration of charges/currents. At the same time, we disclose the impossibility to add this force term covariantly to the Lorentz force law in material media. We further show that the adoption of the Einstein–Laub force law does not resolve the issue, because for a small electric/magnetic dipole, the density ofmore » Einstein–Laub force integrates exactly to the same equation, like the Lorentz force with the inclusion of hidden momentum contribution. Thus, none of the available expressions for the force on a moving dipole is compatible with the relativistic transformation of force, and we support this statement with a number of particular examples. In this respect, we suggest applying the Lagrangian approach to the derivation of the force law in a magnetized/polarized medium. In the framework of this approach we obtain the novel expression for the force on a small electric/magnetic dipole, with the novel expression for its generalized momentum. The latter expression implies two novel quantum effects with non-topological phases, when an electric dipole is moving in an electric field, and when a magnetic dipole is moving in a magnetic field. These phases, in general, are not related to dynamical effects, because they are not equal to zero, when the classical force on a dipole is vanishing. The implications of the obtained results are discussed.« less
NASA Astrophysics Data System (ADS)
Leonov, G. A.; Kuznetsov, N. V.
From a computational point of view, in nonlinear dynamical systems, attractors can be regarded as self-excited and hidden attractors. Self-excited attractors can be localized numerically by a standard computational procedure, in which after a transient process a trajectory, starting from a point of unstable manifold in a neighborhood of equilibrium, reaches a state of oscillation, therefore one can easily identify it. In contrast, for a hidden attractor, a basin of attraction does not intersect with small neighborhoods of equilibria. While classical attractors are self-excited, attractors can therefore be obtained numerically by the standard computational procedure. For localization of hidden attractors it is necessary to develop special procedures, since there are no similar transient processes leading to such attractors. At first, the problem of investigating hidden oscillations arose in the second part of Hilbert's 16th problem (1900). The first nontrivial results were obtained in Bautin's works, which were devoted to constructing nested limit cycles in quadratic systems, that showed the necessity of studying hidden oscillations for solving this problem. Later, the problem of analyzing hidden oscillations arose from engineering problems in automatic control. In the 50-60s of the last century, the investigations of widely known Markus-Yamabe's, Aizerman's, and Kalman's conjectures on absolute stability have led to the finding of hidden oscillations in automatic control systems with a unique stable stationary point. In 1961, Gubar revealed a gap in Kapranov's work on phase locked-loops (PLL) and showed the possibility of the existence of hidden oscillations in PLL. At the end of the last century, the difficulties in analyzing hidden oscillations arose in simulations of drilling systems and aircraft's control systems (anti-windup) which caused crashes. Further investigations on hidden oscillations were greatly encouraged by the present authors' discovery, in 2010 (for the first time), of chaotic hidden attractor in Chua's circuit. This survey is dedicated to efficient analytical-numerical methods for the study of hidden oscillations. Here, an attempt is made to reflect the current trends in the synthesis of analytical and numerical methods.
System and method for evaluating wind flow fields using remote sensing devices
Schroeder, John; Hirth, Brian; Guynes, Jerry
2016-12-13
The present invention provides a system and method for obtaining data to determine one or more characteristics of a wind field using a first remote sensing device and a second remote sensing device. Coordinated data is collected from the first and second remote sensing devices and analyzed to determine the one or more characteristics of the wind field. The first remote sensing device is positioned to have a portion of the wind field within a first scanning sector of the first remote sensing device. The second remote sensing device is positioned to have the portion of the wind field disposed within a second scanning sector of the second remote sensing device.
Conformal field algebras with quantum symmetry from the theory of superselection sectors
NASA Astrophysics Data System (ADS)
Mack, Gerhard; Schomerus, Volker
1990-11-01
According to the theory of superselection sectors of Doplicher, Haag, and Roberts, field operators which make transitions between different superselection sectors—i.e. different irreducible representations of the observable algebra—are to be constructed by adjoining localized endomorphisms to the algebra of local observables. We find the relevant endomorphisms of the chiral algebra of observables in the minimal conformal model with central charge c=1/2 (Ising model). We show by explicit and elementary construction how they determine a representation of the braid group B ∞ which is associated with a Temperley-Lieb-Jones algebra. We recover fusion rules, and compute the quantum dimensions of the superselection sectors. We exhibit a field algebra which is quantum group covariant and acts in the Hilbert space of physical states. It obeys local braid relations in an appropriate weak sense.
NASA Astrophysics Data System (ADS)
Pham Thi Thu, H.; Amory-Mazaudier, C.; Le Huy, M.
2011-01-01
Quiet days variations in the Earth's magnetic field (the Sq current system) are compared and contrasted for the Asian, African and American sectors using a new dataset from Vietnam. This is the first presentation of the variation of the Earth's magnetic field (Sq), during the solar cycle 23, at Phu Thuy, Vietnam (geographic latitudes 21.03° N and longitude: 105.95° E). Phu Thuy observatory is located below the crest of the equatorial fountain in the Asian longitude sector of the Northern Hemisphere. The morphology of the Sq daily variation is presented as a function of solar cycle and seasons. The diurnal variation of Phu Thuy is compared to those obtained in different magnetic observatories over the world to highlight the characteristics of the Phu Thuy observations. In other longitude sectors we find different patterns. At Phu Thuy the solar cycle variation of the amplitude of the daily variation of the X component is correlated to the F.10.7 cm solar radiation (~0.74). This correlation factor is greater than the correlation factor obtained in two observatories located at the same magnetic latitudes in other longitude sectors: at Tamanrasset in the African sector (~0.42, geographic latitude ~22.79) and San Juan in the American sector (~0.03, geographic latitude ~18.38). At Phu Thuy, the Sq field exhibits an equinoctial and a diurnal asymmetry: - The seasonal variation of the monthly mean of X component exhibits the well known semiannual pattern with 2 equinox maxima, but the X component is larger in spring than in autumn. Depending of the phase of the sunspot cycle, the maximum amplitude of the X component varies in spring from 30 nT to 75 nT and in autumn from 20 nT to 60 nT. The maximum amplitude of the X component exhibits roughly the same variation in both solstices, varying from about ~20 nT to 50 nT, depending on the position into the solar cycle. - In all seasons, the mean equinoctial diurnal Y component has a morning maximum Larger than the afternoon minimum i.e. the equivalent current flow over a day is more southward than northward. During winter, the asymmetry is maximum, it erases the afternoon minimum. At the Gnangara observatory, in Asian Southern Hemisphere, the diurnal Y pattern is opposite and the current flow is more northward. It seems that in the Asian sector, the northern and southern Sq current cells both contribute strongly to the equatorial electrojet. The pattern is different in the African and American sectors where the northern Sq current cell contribution to the equatorial electrojet is smaller than the southern one. These observations can explain the unexpected maximum of amplitude of the equatorial electrojet observed in the Asian sector where the internal field is very large. During winter the Y component flow presents an anomaly, it is always southward during the whole day and there is no afternoon northward circulation.
Capillary electrophoresis-high resolution sector field inductively coupled plasma mass spectrometry.
Sonke, Jeroen E; Salters, Vincent J M
2007-08-03
The background and applications of high resolution sector field inductively coupled plasma mass spectrometry (HR-ICP-MS) as a detector for capillary (CE) and gel electrophoretic separations are reviewed. Notable progress has been made in the fields of bioinorganic and environmental (geo-) chemistry. Metallomics, the study of metal species interactions and functions in biological systems, puts substantial technical demands on speciation analysis. The combination of high species resolving power (CE) and high sensitivity-high mass resolving power (HR-ICP-MS) provides a solid base to meet such demands.
Sector magnets or transverse electromagnetic fields in cylindrical coordinates
Zolkin, T.
2017-04-10
Laplace’s equation is considered for scalar and vector potentials describing electric or magnetic fields in cylindrical coordinates, with invariance along the azimuthal coordinate. In a series, we found special functions which, when expanded to lowest order in power series in radial and vertical coordinates, replicate harmonic polynomials in two variables. These functions are based on radial harmonics found by Edwin M. McMillan forty years ago. In addition to McMillan’s harmonics, a second family of radial harmonics is introduced to provide a symmetric description between electric and magnetic fields and to describe fields and potentials in terms of the same functions.more » Formulas are provided which relate any transverse fields specified by the coefficients in the power series expansion in radial or vertical planes in cylindrical coordinates with the set of new functions. Our result is important for potential theory and for theoretical study, design and proper modeling of sector dipoles, combined function dipoles and any general sector element for accelerator physics. All results are presented in connection with these problems.« less
Field-aligned currents, convection electric fields, and ULF-ELF waves in the cusp
NASA Technical Reports Server (NTRS)
Saflekos, N. A.; Potemra, T. A.; Kintner, P. M., Jr.; Green, J. L.
1979-01-01
Nearly simultaneous observations from the Triad and Hawkeye satellites over the Southern Hemisphere, at low altitudes near the noon meridian and close to the usual polar cusp latitudes, show that in and near the polar cusp there exist several relationships between field-aligned currents (FACs), convection electric fields, ULF-ELF magnetic noise, broadband electrostatic noise and interplanetary magnetic fields. The most important findings are (1) the FACs directed into the ionosphere in the noon-to-dusk local time sector and directed away from the ionosphere in the noon-to-dawn local time sector and identified as region-1 permanent FACs (Iijima and Potemra, 1976a) and are located equatorward of the regions of antisunward (westward) convection; (2) the observations are consistent with a two-cell convection pattern symmetric in one case (throat positioned at noon) and asymmetric in another (throat located in a sector on the forenoon side in juxtaposition to the region of strong convection on the afternoon side); and (3) fine-structure FACs are responsible for the generation of ULF-ELF noise in the polar cusp.
Sector magnets or transverse electromagnetic fields in cylindrical coordinates
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zolkin, T.
Laplace’s equation is considered for scalar and vector potentials describing electric or magnetic fields in cylindrical coordinates, with invariance along the azimuthal coordinate. In a series, we found special functions which, when expanded to lowest order in power series in radial and vertical coordinates, replicate harmonic polynomials in two variables. These functions are based on radial harmonics found by Edwin M. McMillan forty years ago. In addition to McMillan’s harmonics, a second family of radial harmonics is introduced to provide a symmetric description between electric and magnetic fields and to describe fields and potentials in terms of the same functions.more » Formulas are provided which relate any transverse fields specified by the coefficients in the power series expansion in radial or vertical planes in cylindrical coordinates with the set of new functions. Our result is important for potential theory and for theoretical study, design and proper modeling of sector dipoles, combined function dipoles and any general sector element for accelerator physics. All results are presented in connection with these problems.« less
Health reform in Mexico: the promotion of inequality.
Laurell, A C
2001-01-01
The Mexican health reform can be understood only in the context of neoliberal structural adjustment, and it reveals some of the basic characteristics of similar reforms in the Latin American region. The strategy to transform the predominantly public health care system into a market-driven system has been a complex process with a hidden agenda to avoid political resistance. The compulsory social security system is the key sector in opening health care to private insurance companies, health maintenance organizations, and hospital enterprises mainly from abroad. Despite the government's commitment to universal coverage, equity, efficiency, and quality, the empirical data analyzed in this article do not confirm compliance with these objectives. Although an alternative health policy that gradually grants the constitutional right to health would be feasible, the new democratically elected government will continue the previous regressive health reform.
A search for pair production of new light bosons decaying into muons
Khachatryan, Vardan
2015-11-03
In this study, a search for the pair production of new light bosons, each decaying into a pair of muons, is performed with the CMS experiment at the LHC, using a dataset corresponding to an integrated luminosity of 20.7 fb –1 collected in proton–proton collisions at center-of-mass energy of √s = 8 TeV. No excess is observed in the data relative to standard model background expectation and a model independent upper limit on the product of the cross section, branching fraction, and acceptance is derived. The results are compared with two benchmark models, the first one in the context ofmore » the next-to-minimal supersymmetric standard model, and the second one in scenarios containing a hidden sector, including those predicting a nonnegligible light boson lifetime.« less
ERIC Educational Resources Information Center
Skolnik, Michael L.
2016-01-01
During the last third of the twentieth century, college sectors in many countries took on the role of expanding opportunities for baccalaureate degree attainment in applied fields of study. In many European countries, colleges came to constitute a parallel higher education sector that offered degree programs of an applied nature in contrast to the…
On-site cell field test support program
NASA Astrophysics Data System (ADS)
Staniunas, J. W.; Merten, G. P.
1982-09-01
Utility sites for data monitoring were reviewed and selected. Each of these sites will be instrumented and its energy requirements monitored and analyzed for one year prior to the selection of 40 Kilowatt fuel cell field test sites. Analyses in support of the selection of sites for instrumentation shows that many building sectors offered considerable market potential. These sectors include nursing home, health club, restaurant, industrial, hotel/motel and apartment.
TASK COMPLEXITY MODIFIES THE SEARCH STRATEGY OF RATS.
Ruprecht, Chad M; Taylor, C Drew; Wolf, Joshua E; Leising, Kenneth J
2013-10-25
Human and non-human animals exhibit a variety of response strategies (e.g., place responding) when searching for a familiar place or evading predators. We still know little about the conditions that support the use of each strategy. We trained rats to locate a hidden food reward in a small-scale spatial search task. The complexity of the search task was manipulated by reducing the number of search locations (25, 4, and 2) within an open-field apparatus and by comparison to a path-based apparatus (plus maze). After rats were trained to reliably locate the hidden food, each apparatus was shifted to gauge whether rats were searching at the location of the goal relative to extramaze cues (i.e., place responding), or searching in the direction of the goal relative to a combination of intramaze and extramaze cues (i.e., directional responding). The results indicate that the open field supported place responding when more than two response locations were present, whereas, the four-arm plus-maze supported strong directional responding. These results extend prior research into the role of task demands on search strategy, as well as support the use of the four-choice open field as an analog to the Morris water task for future studies targeting the neural underpinnings of place responding. Copyright © 2013 Elsevier B.V. All rights reserved.
Washington, Michael A; Blythe, Jauchia
The recent capture of a terrorist in Belgium carrying explosives, fecal matter, and animal tissue may indicate a shift from conventional weapons to crude bacteriological preparations as instruments of terror. It is important to note that although such weapons lack technological sophistication, bacteria are inherently complex, unpredictable, and undetectable in the field. Therefore, it is important that Special Operations medical personnel understand the complications that such seemingly simple devices can add to the treatment of casualties in the field and subsequent evaluation in the clinic. 2016.
Hidden conformal symmetry of rotating black holes in minimal five-dimensional gauged supergravity
DOE Office of Scientific and Technical Information (OSTI.GOV)
Setare, M. R.; Kamali, V.
2010-10-15
In the present paper we show that for a low frequency limit the wave equation of a massless scalar field in the background of nonextremal charged rotating black holes in five-dimensional minimal gauged and ungauged supergravity can be written as the Casimir of an SL(2,R) symmetry. Our result shows that the entropy of the black hole is reproduced by the Cardy formula. Also the absorption cross section is consistent with the finite temperature absorption cross section for a two-dimensional conformal field theory.
Viewing Integrated-Circuit Interconnections By SEM
NASA Technical Reports Server (NTRS)
Lawton, Russel A.; Gauldin, Robert E.; Ruiz, Ronald P.
1990-01-01
Back-scattering of energetic electrons reveals hidden metal layers. Experiment shows that with suitable operating adjustments, scanning electron microscopy (SEM) used to look for defects in aluminum interconnections in integrated circuits. Enables monitoring, in situ, of changes in defects caused by changes in temperature. Gives truer picture of defects, as etching can change stress field of metal-and-passivation pattern, causing changes in defects.
The Moral Construction of the Good Pupil Embedded in School Rules
ERIC Educational Resources Information Center
Thornberg, Robert
2009-01-01
The aim of this field study was to investigate the hidden curriculum of school rules delimited to the moral construction of "the good pupil" embedded in the system of school rules in two primary schools. According to the findings, the rule system mediates a moral construction of the good pupil to the children, and this actually includes…
ERIC Educational Resources Information Center
Anwaruddin, Sardar M.
2016-01-01
While the field of second language teacher education (SLTE) has expanded noticeably over the past decade, little attention has been paid to specific approaches to its curriculum. Taking a hidden-curriculum approach, I show that the curriculum of SLTE is focused predominantly on the content, method and assessment of teaching, which I describe as…
NASA Astrophysics Data System (ADS)
Lipetzky, Kirsten G.; Novack, Michele R.; Perez, Ignacio; Davis, William R.
2001-11-01
Three different innovative nondestructive evaluation technologies were developed and evaluated for the ability to detect fatigue cracks and corrosion hidden under painted aluminum panels. The three technologies included real-time ultrasound imaging, thermal imaging, and near-field microwave imaging. With each of these nondestructive inspection methods, subtasks were performed in order to optimize each methodology.
Mousa, Mohammad F; Cubbidge, Robert P; Al-Mansouri, Fatima; Bener, Abdulbari
2014-02-01
Multifocal visual evoked potential (mfVEP) is a newly introduced method used for objective visual field assessment. Several analysis protocols have been tested to identify early visual field losses in glaucoma patients using the mfVEP technique, some were successful in detection of field defects, which were comparable to the standard automated perimetry (SAP) visual field assessment, and others were not very informative and needed more adjustment and research work. In this study we implemented a novel analysis approach and evaluated its validity and whether it could be used effectively for early detection of visual field defects in glaucoma. Three groups were tested in this study; normal controls (38 eyes), glaucoma patients (36 eyes) and glaucoma suspect patients (38 eyes). All subjects had a two standard Humphrey field analyzer (HFA) test 24-2 and a single mfVEP test undertaken in one session. Analysis of the mfVEP results was done using the new analysis protocol; the hemifield sector analysis (HSA) protocol. Analysis of the HFA was done using the standard grading system. Analysis of mfVEP results showed that there was a statistically significant difference between the three groups in the mean signal to noise ratio (ANOVA test, p < 0.001 with a 95% confidence interval). The difference between superior and inferior hemispheres in all subjects were statistically significant in the glaucoma patient group in all 11 sectors (t-test, p < 0.001), partially significant in 5 / 11 (t-test, p < 0.01), and no statistical difference in most sectors of the normal group (1 / 11 sectors was significant, t-test, p < 0.9). Sensitivity and specificity of the HSA protocol in detecting glaucoma was 97% and 86%, respectively, and for glaucoma suspect patients the values were 89% and 79%, respectively. The new HSA protocol used in the mfVEP testing can be applied to detect glaucomatous visual field defects in both glaucoma and glaucoma suspect patients. Using this protocol can provide information about focal visual field differences across the horizontal midline, which can be utilized to differentiate between glaucoma and normal subjects. Sensitivity and specificity of the mfVEP test showed very promising results and correlated with other anatomical changes in glaucoma field loss.
Mousa, Mohammad F.; Cubbidge, Robert P.; Al-Mansouri, Fatima
2014-01-01
Purpose Multifocal visual evoked potential (mfVEP) is a newly introduced method used for objective visual field assessment. Several analysis protocols have been tested to identify early visual field losses in glaucoma patients using the mfVEP technique, some were successful in detection of field defects, which were comparable to the standard automated perimetry (SAP) visual field assessment, and others were not very informative and needed more adjustment and research work. In this study we implemented a novel analysis approach and evaluated its validity and whether it could be used effectively for early detection of visual field defects in glaucoma. Methods Three groups were tested in this study; normal controls (38 eyes), glaucoma patients (36 eyes) and glaucoma suspect patients (38 eyes). All subjects had a two standard Humphrey field analyzer (HFA) test 24-2 and a single mfVEP test undertaken in one session. Analysis of the mfVEP results was done using the new analysis protocol; the hemifield sector analysis (HSA) protocol. Analysis of the HFA was done using the standard grading system. Results Analysis of mfVEP results showed that there was a statistically significant difference between the three groups in the mean signal to noise ratio (ANOVA test, p < 0.001 with a 95% confidence interval). The difference between superior and inferior hemispheres in all subjects were statistically significant in the glaucoma patient group in all 11 sectors (t-test, p < 0.001), partially significant in 5 / 11 (t-test, p < 0.01), and no statistical difference in most sectors of the normal group (1 / 11 sectors was significant, t-test, p < 0.9). Sensitivity and specificity of the HSA protocol in detecting glaucoma was 97% and 86%, respectively, and for glaucoma suspect patients the values were 89% and 79%, respectively. Conclusions The new HSA protocol used in the mfVEP testing can be applied to detect glaucomatous visual field defects in both glaucoma and glaucoma suspect patients. Using this protocol can provide information about focal visual field differences across the horizontal midline, which can be utilized to differentiate between glaucoma and normal subjects. Sensitivity and specificity of the mfVEP test showed very promising results and correlated with other anatomical changes in glaucoma field loss. PMID:24511212
An alternative resolution to the Mansuripur paradox
NASA Astrophysics Data System (ADS)
Redfern, Francis
2016-04-01
In 2013 an article published online by the journal Science declared that the paradox proposed by Masud Mansuripur was resolved. This paradox concerns a point charge-Amperian magnetic dipole system as seen in a frame of reference where they are at rest and one in which they are moving. In the latter frame an electric dipole appears on the magnetic dipole. A torque is then exerted upon the electric dipole by the point charge, a torque that is not observed in the at-rest frame. Mansuripur points out this violates the relativity principle and suggests the Lorentz force responsible for the torque be replaced by the Einstein-Laub force. The resolution of the paradox reported by Science, based on numerous papers in the physics literature, preserves the Lorentz force but depends on the concept of hidden momentum. Here I propose a different resolution based on the overlooked fact that the charge-magnetic dipole system contains linear and angular electromagnetic field momentum. The time rate of change of the field angular-momentum in the frame through which the system is moving cancels that due to the charge-electric dipole interaction. From this point of view hidden momentum is not needed in the resolution of the paradox.
NASA Astrophysics Data System (ADS)
Guerrout, EL-Hachemi; Ait-Aoudia, Samy; Michelucci, Dominique; Mahiou, Ramdane
2018-05-01
Many routine medical examinations produce images of patients suffering from various pathologies. With the huge number of medical images, the manual analysis and interpretation became a tedious task. Thus, automatic image segmentation became essential for diagnosis assistance. Segmentation consists in dividing the image into homogeneous and significant regions. We focus on hidden Markov random fields referred to as HMRF to model the problem of segmentation. This modelisation leads to a classical function minimisation problem. Broyden-Fletcher-Goldfarb-Shanno algorithm referred to as BFGS is one of the most powerful methods to solve unconstrained optimisation problem. In this paper, we investigate the combination of HMRF and BFGS algorithm to perform the segmentation operation. The proposed method shows very good segmentation results comparing with well-known approaches. The tests are conducted on brain magnetic resonance image databases (BrainWeb and IBSR) largely used to objectively confront the results obtained. The well-known Dice coefficient (DC) was used as similarity metric. The experimental results show that, in many cases, our proposed method approaches the perfect segmentation with a Dice Coefficient above .9. Moreover, it generally outperforms other methods in the tests conducted.
Hame, Yrjo; Angelini, Elsa D; Hoffman, Eric A; Barr, R Graham; Laine, Andrew F
2014-07-01
The extent of pulmonary emphysema is commonly estimated from CT scans by computing the proportional area of voxels below a predefined attenuation threshold. However, the reliability of this approach is limited by several factors that affect the CT intensity distributions in the lung. This work presents a novel method for emphysema quantification, based on parametric modeling of intensity distributions and a hidden Markov measure field model to segment emphysematous regions. The framework adapts to the characteristics of an image to ensure a robust quantification of emphysema under varying CT imaging protocols, and differences in parenchymal intensity distributions due to factors such as inspiration level. Compared to standard approaches, the presented model involves a larger number of parameters, most of which can be estimated from data, to handle the variability encountered in lung CT scans. The method was applied on a longitudinal data set with 87 subjects and a total of 365 scans acquired with varying imaging protocols. The resulting emphysema estimates had very high intra-subject correlation values. By reducing sensitivity to changes in imaging protocol, the method provides a more robust estimate than standard approaches. The generated emphysema delineations promise advantages for regional analysis of emphysema extent and progression.
The Chern-Simons current in time series of knots and links in proteins
NASA Astrophysics Data System (ADS)
Capozziello, Salvatore; Pincak, Richard
2018-06-01
A superspace model of knots and links for DNA time series data is proposed to take into account the feedback loop from docking to undocking state of protein-protein interactions. In particular, the direction of interactions between the 8 hidden states of DNA is considered. It is a E8 ×E8 unified spin model where the genotype, from active and inactive side of DNA time data series, can be considered for any living organism. The mathematical model is borrowed from loop-quantum gravity and adapted to biology. It is used to derive equations for gene expression describing transitions from ground to excited states, and for the 8 coupling states between geneon and anti-geneon transposon and retrotransposon in trash DNA. Specifically, we adopt a modified Grothendieck cohomology and a modified Khovanov cohomology for biology. The result is a Chern-Simons current in (8 + 3) extradimensions of a given unoriented supermanifold with ghost fields of protein structures. The 8 dimensions come from the 8 hidden states of spinor field of genetic code. The extradimensions come from the 3 types of principle fiber bundle in the secondary protein.
Resource allocation strategies in Southeastern European health policy.
Jakovljevic, Mihajlo B
2013-04-01
The past 23 years of post-socialist restructuring of health system funding and management patterns has brought many changes to small Balkan markets, putting them under increasing pressure to keep pace with advancing globalization. Socioeconomic inequalities in healthcare access are still growing across the region. This uneven development is marked by the substantial difficulties encountered by local governments in delivering medical services to broad sectors of the population. This paper presents the results of a systematic review of the following evidence: published reports on health system reforms in the region commissioned by WHO, IMF, World Bank, OECD, European Commission; all available published evidence on health economics, funding, reimbursement in world/local languages since 1989 indexed at Medline, Excerpta Medica and Google Scholar; in depth analysis of official website data on medical care financing related legislation among key public institutions such as national Ministries of health, Health Insurance Funds, Professional Associations were applicable, in local languages; correspondence with key opinion leaders in the field in their respective communities. Contributors were asked to answer a particular set of questions related to the issue, thus enlightening fresh legislative developments and hidden patterns of policy maker's behavior. Cost awareness is slowly expanding in regional management, academic and industrial establishment. The study provides an exact and comprehensive description of its current extent and legislative framework. Western Balkans policy makers would profit substantially from health-economics-based decision-making to cope with increasing difficulties in funding and delivering medical care in emerging markets with a rapidly growing demand for health services.
A minimal model of neutrino flavor
NASA Astrophysics Data System (ADS)
Luhn, Christoph; Parattu, Krishna Mohan; Wingerter, Akın
2012-12-01
Models of neutrino mass which attempt to describe the observed lepton mixing pattern are typically based on discrete family symmetries with a non-Abelian and one or more Abelian factors. The latter so-called shaping symmetries are imposed in order to yield a realistic phenomenology by forbidding unwanted operators. Here we propose a supersymmetric model of neutrino flavor which is based on the group T 7 and does not require extra {Z} N or U(1) factors in the Yukawa sector, which makes it the smallest realistic family symmetry that has been considered so far. At leading order, the model predicts tribimaximal mixing which arises completely accidentally from a combination of the T 7 Clebsch-Gordan coefficients and suitable flavon alignments. Next-to-leading order (NLO) operators break the simple tribimaximal structure and render the model compatible with the recent results of the Daya Bay and Reno collaborations which have measured a reactor angle of around 9°. Problematic NLO deviations of the other two mixing angles can be controlled in an ultraviolet completion of the model. The vacuum alignment mechanism that we use necessitates the introduction of a hidden flavon sector that transforms under a {Z} 6 symmetry, thereby spoiling the minimality of our model whose flavor symmetry is then T 7 × {Z} 6.
Quantum implications of a scale invariant regularization
NASA Astrophysics Data System (ADS)
Ghilencea, D. M.
2018-04-01
We study scale invariance at the quantum level in a perturbative approach. For a scale-invariant classical theory, the scalar potential is computed at a three-loop level while keeping manifest this symmetry. Spontaneous scale symmetry breaking is transmitted at a quantum level to the visible sector (of ϕ ) by the associated Goldstone mode (dilaton σ ), which enables a scale-invariant regularization and whose vacuum expectation value ⟨σ ⟩ generates the subtraction scale (μ ). While the hidden (σ ) and visible sector (ϕ ) are classically decoupled in d =4 due to an enhanced Poincaré symmetry, they interact through (a series of) evanescent couplings ∝ɛ , dictated by the scale invariance of the action in d =4 -2 ɛ . At the quantum level, these couplings generate new corrections to the potential, as scale-invariant nonpolynomial effective operators ϕ2 n +4/σ2 n. These are comparable in size to "standard" loop corrections and are important for values of ϕ close to ⟨σ ⟩. For n =1 , 2, the beta functions of their coefficient are computed at three loops. In the IR limit, dilaton fluctuations decouple, the effective operators are suppressed by large ⟨σ ⟩, and the effective potential becomes that of a renormalizable theory with explicit scale symmetry breaking by the DR scheme (of μ =constant).
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kopp, Joachim; Liu, Jia; Slatyer, Tracy
Here, we consider dark matter models in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario \\Impeded Dark Matter". We also demonstrate that Impeded Dark Matter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded Dark Matter depends linearly on the dark matter velocity or may evenmore » be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded Dark Matter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. Furthermore, for positive mass splitting, we show that the annihilation cross-section is suppressed by the small mass splitting, which helps light dark matter to survive increasingly stringent constraints from indirect searches. As specific realizations for Impeded Dark Matter, we introduce a model of vector dark matter from a hidden SU(2) sector, and a composite dark matter scenario based on a QCD-like dark sector.« less
Kopp, Joachim; Liu, Jia; Slatyer, Tracy; ...
2016-12-12
Here, we consider dark matter models in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario \\Impeded Dark Matter". We also demonstrate that Impeded Dark Matter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded Dark Matter depends linearly on the dark matter velocity or may evenmore » be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded Dark Matter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. Furthermore, for positive mass splitting, we show that the annihilation cross-section is suppressed by the small mass splitting, which helps light dark matter to survive increasingly stringent constraints from indirect searches. As specific realizations for Impeded Dark Matter, we introduce a model of vector dark matter from a hidden SU(2) sector, and a composite dark matter scenario based on a QCD-like dark sector.« less
NASA Astrophysics Data System (ADS)
Huang, Haiping
2017-05-01
Revealing hidden features in unlabeled data is called unsupervised feature learning, which plays an important role in pretraining a deep neural network. Here we provide a statistical mechanics analysis of the unsupervised learning in a restricted Boltzmann machine with binary synapses. A message passing equation to infer the hidden feature is derived, and furthermore, variants of this equation are analyzed. A statistical analysis by replica theory describes the thermodynamic properties of the model. Our analysis confirms an entropy crisis preceding the non-convergence of the message passing equation, suggesting a discontinuous phase transition as a key characteristic of the restricted Boltzmann machine. Continuous phase transition is also confirmed depending on the embedded feature strength in the data. The mean-field result under the replica symmetric assumption agrees with that obtained by running message passing algorithms on single instances of finite sizes. Interestingly, in an approximate Hopfield model, the entropy crisis is absent, and a continuous phase transition is observed instead. We also develop an iterative equation to infer the hyper-parameter (temperature) hidden in the data, which in physics corresponds to iteratively imposing Nishimori condition. Our study provides insights towards understanding the thermodynamic properties of the restricted Boltzmann machine learning, and moreover important theoretical basis to build simplified deep networks.
Invisible waves and hidden realms: augmented reality and experimental art
NASA Astrophysics Data System (ADS)
Ruzanka, Silvia
2012-03-01
Augmented reality is way of both altering the visible and revealing the invisible. It offers new opportunities for artistic exploration through virtual interventions in real space. In this paper, the author describes the implementation of two art installations using different AR technologies, one using optical marker tracking on mobile devices and one integrating stereoscopic projections into the physical environment. The first artwork, De Ondas y Abejas (The Waves and the Bees), is based on the widely publicized (but unproven) hypothesis of a link between cellphone radiation and the phenomenon of bee colony collapse disorder. Using an Android tablet, viewers search out small fiducial markers in the shape of electromagnetic waves hidden throughout the gallery, which reveal swarms of bees scattered on the floor. The piece also creates a generative soundscape based on electromagnetic fields. The second artwork, Urban Fauna, is a series of animations in which features of the urban landscape become plants and animals. Surveillance cameras become flocks of birds while miniature cellphone towers, lampposts, and telephone poles grow like small seedlings in time-lapse animation. The animations are presented as small stereoscopic projections, integrated into the physical space of the gallery. These two pieces explore the relationship between nature and technology through the visualization of invisible forces and hidden alternate realities.
Colonoscopy video quality assessment using hidden Markov random fields
NASA Astrophysics Data System (ADS)
Park, Sun Young; Sargent, Dusty; Spofford, Inbar; Vosburgh, Kirby
2011-03-01
With colonoscopy becoming a common procedure for individuals aged 50 or more who are at risk of developing colorectal cancer (CRC), colon video data is being accumulated at an ever increasing rate. However, the clinically valuable information contained in these videos is not being maximally exploited to improve patient care and accelerate the development of new screening methods. One of the well-known difficulties in colonoscopy video analysis is the abundance of frames with no diagnostic information. Approximately 40% - 50% of the frames in a colonoscopy video are contaminated by noise, acquisition errors, glare, blur, and uneven illumination. Therefore, filtering out low quality frames containing no diagnostic information can significantly improve the efficiency of colonoscopy video analysis. To address this challenge, we present a quality assessment algorithm to detect and remove low quality, uninformative frames. The goal of our algorithm is to discard low quality frames while retaining all diagnostically relevant information. Our algorithm is based on a hidden Markov model (HMM) in combination with two measures of data quality to filter out uninformative frames. Furthermore, we present a two-level framework based on an embedded hidden Markov model (EHHM) to incorporate the proposed quality assessment algorithm into a complete, automated diagnostic image analysis system for colonoscopy video.
Craig, Sienna R; Scott, Rebekah; Blackwood, Kristy
2018-04-23
Nascent medical students' first view into medical school orients them toward what is considered important in medicine. Based on ethnography conducted over 18 months at a New England medical school, this article explores themes which emerged during a first-year student orientation and examines how these scripts resurface across a four-year curriculum, revealing dynamics of enculturation into an institution and the broader profession. We analyze orientation activities as discursive and embodied fields which serve "practical" purposes of making new social geographies familiar, but which also frame institutional values surrounding "soft" aspects of medicine: professionalism; dynamics of hierarchy and vulnerability; and social difference. By examining orientation and connecting these insights to later, discerning educational moments, we argue that orientation reveals tensions between the overt and hidden curricula within medical education, including what being a good doctor means. Our findings are based on data from semi-structured interviews, focus groups, and participant-observation in didactic and clinical settings. This article answers calls within medical anthropology and medical education literature to recognize implicit values at play in producing physicians, unearthing ethnographically how these values are learned longitudinally via persisting gaps between formal and hidden curricula. Assumptions hidden in plain sight call for ongoing medical education reform.
Weakly supervised visual dictionary learning by harnessing image attributes.
Gao, Yue; Ji, Rongrong; Liu, Wei; Dai, Qionghai; Hua, Gang
2014-12-01
Bag-of-features (BoFs) representation has been extensively applied to deal with various computer vision applications. To extract discriminative and descriptive BoF, one important step is to learn a good dictionary to minimize the quantization loss between local features and codewords. While most existing visual dictionary learning approaches are engaged with unsupervised feature quantization, the latest trend has turned to supervised learning by harnessing the semantic labels of images or regions. However, such labels are typically too expensive to acquire, which restricts the scalability of supervised dictionary learning approaches. In this paper, we propose to leverage image attributes to weakly supervise the dictionary learning procedure without requiring any actual labels. As a key contribution, our approach establishes a generative hidden Markov random field (HMRF), which models the quantized codewords as the observed states and the image attributes as the hidden states, respectively. Dictionary learning is then performed by supervised grouping the observed states, where the supervised information is stemmed from the hidden states of the HMRF. In such a way, the proposed dictionary learning approach incorporates the image attributes to learn a semantic-preserving BoF representation without any genuine supervision. Experiments in large-scale image retrieval and classification tasks corroborate that our approach significantly outperforms the state-of-the-art unsupervised dictionary learning approaches.
Lauridsen, S M R; Norup, M S; Rossel, P J H
2007-12-01
Rationing healthcare is a difficult task, which includes preventing patients from accessing potentially beneficial treatments. Proponents of implicit rationing argue that politicians cannot resist pressure from strong patient groups for treatments and conclude that physicians should ration without informing patients or the public. The authors subdivide this specific programme of implicit rationing, or "hidden rationing", into local hidden rationing, unsophisticated global hidden rationing and sophisticated global hidden rationing. They evaluate the appropriateness of these methods of rationing from the perspectives of individual and political autonomy and conclude that local hidden rationing and unsophisticated global hidden rationing clearly violate patients' individual autonomy, that is, their right to participate in medical decision-making. While sophisticated global hidden rationing avoids this charge, the authors point out that it nonetheless violates the political autonomy of patients, that is, their right to engage in public affairs as citizens. A defence of any of the forms of hidden rationing is therefore considered to be incompatible with a defence of autonomy.
The Hidden Curriculum as Emancipatory and Non-Emancipatory Tools.
ERIC Educational Resources Information Center
Kanpol, Barry
Moral values implied in school practices and policies constitute the "hidden curriculum." Because the hidden curriculum may promote certain moral values to students, teachers are partially responsible for the moral education of students. A component of the hidden curriculum, institutional political resistance, concerns teacher opposition to…
Democratic superstring field theory: gauge fixing
NASA Astrophysics Data System (ADS)
Kroyter, Michael
2011-03-01
We show that a partial gauge fixing of the NS sector of the democratic-picture superstring field theory leads to the non-polynomial theory. Moreover, by partially gauge fixing the Ramond sector we obtain a non-polynomial fully RNS theory at pictures 0 and 1/2 . Within the democratic theory and in the partially gauge fixed theory the equations of motion of both sectors are derived from an action. We also discuss a representation of the non-polynomial theory analogous to a manifestly two-dimensional representation of WZW theory and the action of bosonic pure-gauge solutions. We further demonstrate that one can consistently gauge fix the NS sector of the democratic theory at picture number -1. The resulting theory is new. It is a {mathbb{Z}_2} dual of the modified cubic theory. We construct analytical solutions of this theory and show that they possess the desired properties.
NASA Astrophysics Data System (ADS)
Baxter, J. Erik; Winstanley, Elizabeth
2016-02-01
We investigate the stability of spherically symmetric, purely magnetic, soliton and black hole solutions of four-dimensional 𝔰𝔲(N) Einstein-Yang-Mills theory with a negative cosmological constant Λ. These solutions are described by N - 1 magnetic gauge field functions ωj. We consider linear, spherically symmetric, perturbations of these solutions. The perturbations decouple into two sectors, known as the sphaleronic and gravitational sectors. For any N, there are no instabilities in the sphaleronic sector if all the magnetic gauge field functions ωj have no zeros and satisfy a set of N - 1 inequalities. In the gravitational sector, we prove that there are solutions which have no instabilities in a neighbourhood of stable embedded 𝔰𝔲(2) solutions, provided the magnitude of the cosmological constant |" separators=" Λ | is sufficiently large.
Structure and Evoluton of the Large Scale Solar and Heliospheric Magnetic Fields.
1984-04-01
symmetric about the equator and therefore reinforces the dipole field. This has the effect of pushing the current sheet toward the equator as shown in Figure...drift only slightly in longitude. The postive sector near 90’ remains strong through the year too. The positive sector near 2700 appears to grow in...sheet position determined from coronal polarization brightness measurements from the Mauna Loa coronameter. An immediate problem with using the
Middle- and low-latitude ionosphere response to 2015 St. Patrick's Day geomagnetic storm
NASA Astrophysics Data System (ADS)
Nava, B.; Rodríguez-Zuluaga, J.; Alazo-Cuartas, K.; Kashcheyev, A.; Migoya-Orué, Y.; Radicella, S. M.; Amory-Mazaudier, C.; Fleury, R.
2016-04-01
This paper presents a study of the St Patrick's Day storm of 2015, with its ionospheric response at middle and low latitudes. The effects of the storm in each longitudinal sector (Asian, African, American, and Pacific) are characterized using global and regional electron content. At the beginning of the storm, one or two ionospheric positive storm effects are observed depending on the longitudinal zones. After the main phase of the storm, a strong decrease in ionization is observed at all longitudes, lasting several days. The American region exhibits the most remarkable increase in vertical total electron content (vTEC), while in the Asian sector, the largest decrease in vTEC is observed. At low latitudes, using spectral analysis, we were able to separate the effects of the prompt penetration of the magnetospheric convection electric field (PPEF) and of the disturbance dynamo electric field (DDEF) on the basis of ground magnetic data. Concerning the PPEF, Earth's magnetic field oscillations occur simultaneously in the Asian, African, and American sectors, during southward magnetization of the Bz component of the interplanetary magnetic field. Concerning the DDEF, diurnal magnetic oscillations in the horizontal component H of the Earth's magnetic field exhibit a behavior that is opposed to the regular one. These diurnal oscillations are recognized to last several days in all longitudinal sectors. The observational data obtained by all sensors used in the present paper can be interpreted on the basis of existing theoretical models.
Smart fastener for KC-135 structural integrity monitoring
NASA Astrophysics Data System (ADS)
Schoess, Jeffrey N.; Seifert, Greg
1997-06-01
Hidden and inaccessible corrosion in aircraft structures is the number-one logistics problem for the U.S. Air Force, with an estimated maintenance cost in excess of $DOL1.0 billion per year in 1990-equivalent dollars. The Smart Aircraft Fastener Evaluation (SAFE) system is being developed to provide early warning detection of corrosion- related symptoms in hidden locations of aircraft structures. The SAFE incorporates an in situ measurement approach that measures and autonomously records several environmental conditions (i.e., pH, temperature, chloride, free potential, time-of-wetness) within a Hi-Lok aircraft fastener that could cause corrosion to occur. The SAFE system integrates a miniature electrochemical microsensor array and a time-of- wetness sensor with an ultra-low-power 8-bit microcontroller and 5-Mbyte solid-state FLASH archival memory to measure the evidence of active corrosion. A summary of the technical approach, system design definition, software architecture, and future field test plans will be presented.
Passive Acoustic Leak Detection for Sodium Cooled Fast Reactors Using Hidden Markov Models
NASA Astrophysics Data System (ADS)
Marklund, A. Riber; Kishore, S.; Prakash, V.; Rajan, K. K.; Michel, F.
2016-06-01
Acoustic leak detection for steam generators of sodium fast reactors have been an active research topic since the early 1970s and several methods have been tested over the years. Inspired by its success in the field of automatic speech recognition, we here apply hidden Markov models (HMM) in combination with Gaussian mixture models (GMM) to the problem. To achieve this, we propose a new feature calculation scheme, based on the temporal evolution of the power spectral density (PSD) of the signal. Using acoustic signals recorded during steam/water injection experiments done at the Indira Gandhi Centre for Atomic Research (IGCAR), the proposed method is tested. We perform parametric studies on the HMM+GMM model size and demonstrate that the proposed method a) performs well without a priori knowledge of injection noise, b) can incorporate several noise models and c) has an output distribution that simplifies false alarm rate control.
Gerassi, Lara; Edmond, Tonya; Nichols, Andrea
2017-06-01
The study of sex trafficking, prostitution, sex work, and sexual exploitation is associated with many methodological issues and challenges. Researchers' study designs must consider the many safety issues related to this vulnerable and hidden population. Community advisory boards and key stakeholder involvement are essential to study design to increase safety of participants, usefulness of study aims, and meaningfulness of conclusions. Nonrandomized sampling strategies are most often utilized when studying exploited women and girls, which have the capacity to provide rich data and require complex sampling and recruitment methods. This article reviews the current methodological issues when studying this marginalized population as well as strategies to address challenges while working with the community in order to bring about social change. The authors also discuss their own experiences in collaborating with community organizations to conduct research in this field.
Gerassi, Lara; Edmond, Tonya; Nichols, Andrea
2016-01-01
The study of sex trafficking, prostitution, sex work, and sexual exploitation is associated with many methodological issues and challenges. Researchers’ study designs must consider the many safety issues related to this vulnerable and hidden population. Community advisory boards and key stakeholder involvement are essential to study design to increase safety of participants, usefulness of study aims, and meaningfulness of conclusions. Nonrandomized sampling strategies are most often utilized when studying exploited women and girls, which have the capacity to provide rich data and require complex sampling and recruitment methods. This article reviews the current methodological issues when studying this marginalized population as well as strategies to address challenges while working with the community in order to bring about social change. The authors also discuss their own experiences in collaborating with community organizations to conduct research in this field. PMID:28824337
Scale-chiral symmetry, ω meson, and dense baryonic matter
NASA Astrophysics Data System (ADS)
Ma, Yong-Liang; Rho, Mannque
2018-05-01
It is shown that explicitly broken scale symmetry is essential for dense skyrmion matter in hidden local symmetry theory. Consistency with the vector manifestation fixed point for the hidden local symmetry of the lowest-lying vector mesons and the dilaton limit fixed point for scale symmetry in dense matter is found to require that the anomalous dimension (|γG2| ) of the gluon field strength tensor squared (G2 ) that represents the quantum trace anomaly should be 1.0 ≲|γG2|≲3.5 . The magnitude of |γG2| estimated here will be useful for studying hadron and nuclear physics based on the scale-chiral effective theory. More significantly, that the dilaton limit fixed point can be arrived at with γG2≠0 at some high density signals that scale symmetry can arise in dense medium as an "emergent" symmetry.
Quantum steganography with large payload based on entanglement swapping of χ-type entangled states
NASA Astrophysics Data System (ADS)
Qu, Zhi-Guo; Chen, Xiu-Bo; Luo, Ming-Xing; Niu, Xin-Xin; Yang, Yi-Xian
2011-04-01
In this paper, we firstly propose a new simple method to calculate entanglement swapping of χ-type entangled states, and then present a novel quantum steganography protocol with large payload. The new protocol adopts entanglement swapping to build up the hidden channel within quantum secure direct communication with χ-type entangled states for securely transmitting secret messages. Comparing with the previous quantum steganographies, the capacity of the hidden channel is much higher, which is increased to eight bits. Meanwhile, due to the quantum uncertainty theorem and the no-cloning theorem its imperceptibility is proved to be great in the analysis, and its security is also analyzed in detail, which is proved that intercept-resend attack, measurement-resend attack, ancilla attack, man-in-the-middle attack or even Dos(Denial of Service) attack couldn't threaten it. As a result, the protocol can be applied in various fields of quantum communication.
A Novel Extreme Learning Control Framework of Unmanned Surface Vehicles.
Wang, Ning; Sun, Jing-Chao; Er, Meng Joo; Liu, Yan-Cheng
2016-05-01
In this paper, an extreme learning control (ELC) framework using the single-hidden-layer feedforward network (SLFN) with random hidden nodes for tracking an unmanned surface vehicle suffering from unknown dynamics and external disturbances is proposed. By combining tracking errors with derivatives, an error surface and transformed states are defined to encapsulate unknown dynamics and disturbances into a lumped vector field of transformed states. The lumped nonlinearity is further identified accurately by an extreme-learning-machine-based SLFN approximator which does not require a priori system knowledge nor tuning input weights. Only output weights of the SLFN need to be updated by adaptive projection-based laws derived from the Lyapunov approach. Moreover, an error compensator is incorporated to suppress approximation residuals, and thereby contributing to the robustness and global asymptotic stability of the closed-loop ELC system. Simulation studies and comprehensive comparisons demonstrate that the ELC framework achieves high accuracy in both tracking and approximation.
Chemical Bonding: The Orthogonal Valence-Bond View
Sax, Alexander F.
2015-01-01
Chemical bonding is the stabilization of a molecular system by charge- and spin-reorganization processes in chemical reactions. These processes are said to be local, because the number of atoms involved is very small. With multi-configurational self-consistent field (MCSCF) wave functions, these processes can be calculated, but the local information is hidden by the delocalized molecular orbitals (MO) used to construct the wave functions. The transformation of such wave functions into valence bond (VB) wave functions, which are based on localized orbitals, reveals the hidden information; this transformation is called a VB reading of MCSCF wave functions. The two-electron VB wave functions describing the Lewis electron pair that connects two atoms are frequently called covalent or neutral, suggesting that these wave functions describe an electronic situation where two electrons are never located at the same atom; such electronic situations and the wave functions describing them are called ionic. When the distance between two atoms decreases, however, every covalent VB wave function composed of non-orthogonal atomic orbitals changes its character from neutral to ionic. However, this change in the character of conventional VB wave functions is hidden by its mathematical form. Orthogonal VB wave functions composed of orthonormalized orbitals never change their character. When localized fragment orbitals are used instead of atomic orbitals, one can decide which local information is revealed and which remains hidden. In this paper, we analyze four chemical reactions by transforming the MCSCF wave functions into orthogonal VB wave functions; we show how the reactions are influenced by changing the atoms involved or by changing their local symmetry. Using orthogonal instead of non-orthogonal orbitals is not just a technical issue; it also changes the interpretation, revealing the properties of wave functions that remain otherwise undetected. PMID:25906476
ERIC Educational Resources Information Center
Flood, Johnna; Minkler, Meredith; Lavery, Susana Hennessey; Estrada, Jessica; Falbe, Jennifer
2015-01-01
As resources for health promotion become more constricted, it is increasingly important to collaborate across sectors, including the private sector. Although many excellent models for cross-sector collaboration have shown promise in the health field, collective impact (CI), an emerging model for creating larger scale change, has yet to receive…
Photoacoustic imaging of hidden dental caries by using a fiber-based probing system
NASA Astrophysics Data System (ADS)
Koyama, Takuya; Kakino, Satoko; Matsuura, Yuji
2017-04-01
Photoacoustic method to detect hidden dental caries is proposed. It was found that high frequency ultrasonic waves are generated from hidden carious part when radiating laser light to occlusal surface of model tooth. By making a map of intensity of these high frequency components, photoacoustic images of hidden caries were successfully obtained. A photoacoustic imaging system using a bundle of hollow optical fiber was fabricated for using clinical application, and clear photoacoustic image of hidden caries was also obtained by this system.
Reducing pesticide risks to farming communities: cotton farmer field schools in Mali
Settle, William; Soumaré, Mohamed; Sarr, Makhfousse; Garba, Mohamed Hama; Poisot, Anne-Sophie
2014-01-01
We provide results from a study of two separate sectors within the cotton-growing region of southern Mali. In one sector, farmers have engaged in a farmer field school (FFS) training programme since 2003—the other not. One goal of the training was the adoption of alternatives to the use of hazardous insecticides, through integrated pest management (IPM) methods. Over an 8-year period, analysis showed that with roughly 20% of the 4324 cotton-growing farm households having undergone training, hazardous insecticide use for the entire sector fell by 92.5% compared with earlier figures and with the second (control) sector. Yields for cotton in both sectors were highly variable over time, but no evidence was found for changes in yield owing to shifts in pest management practices. Evidence is presented for a likely diffusion of new practices having taken place, from FFS participants to non-participants. We discuss strengths and weaknesses of the FFS approach, in general, and highlight the need for improved baseline survey and impact analyses to be integrated into FFS projects. PMID:24535387
Phase diagram of URu 2–xFe xSi 2 in high magnetic fields
Ran, Sheng; Jeon, Inho; Pouse, Naveen; ...
2017-08-28
Here, electrical transport measurements were performed on URu 2-xFe xSi 2 single-crystal specimens in high magnetic fields up to 45 T (DC fields) and 60 T (pulsed fields). We observed a systematic evolution of the critical fields for both the hidden-order (HO) and large-moment antiferromagnetic (LMAFM) phases and established the 3D phase diagram of T–H–x. In the HO phase, H/H 0 scales with T/T 0 and collapses onto a single curve. However, in the LMAFM phase, this single scaling relation is not satisfied. Within a certain range of x values, the HO phase reenters after the LMAFM phase is suppressedmore » by the magnetic field, similar to the behavior observed for URu 2Si 2 within a certain range of pressures.« less
Phase diagram of URu 2–xFe xSi 2 in high magnetic fields
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ran, Sheng; Jeon, Inho; Pouse, Naveen
Here, electrical transport measurements were performed on URu 2-xFe xSi 2 single-crystal specimens in high magnetic fields up to 45 T (DC fields) and 60 T (pulsed fields). We observed a systematic evolution of the critical fields for both the hidden-order (HO) and large-moment antiferromagnetic (LMAFM) phases and established the 3D phase diagram of T–H–x. In the HO phase, H/H 0 scales with T/T 0 and collapses onto a single curve. However, in the LMAFM phase, this single scaling relation is not satisfied. Within a certain range of x values, the HO phase reenters after the LMAFM phase is suppressedmore » by the magnetic field, similar to the behavior observed for URu 2Si 2 within a certain range of pressures.« less
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Natural hidden antibodies reacting with DNA or cardiolipin bind to thymocytes and evoke their death.
Zamulaeva, I A; Lekakh, I V; Kiseleva, V I; Gabai, V L; Saenko, A S; Shevchenko, A S; Poverenny, A M
1997-08-18
Both free and hidden natural antibodies to DNA or cardiolipin were obtained from immunoglobulins of a normal donor. The free antibodies reacting with DNA or cardiolipin were isolated by means of affinity chromatography. Antibodies occurring in an hidden state were disengaged from the depleted immunoglobulins by ion-exchange chromatography and were then affinity-isolated on DNA or cardiolipin sorbents. We used flow cytometry to study the ability of free and hidden antibodies to bind to rat thymocytes. Simultaneously, plasma membrane integrity was tested by propidium iodide (PI) exclusion. The hidden antibodies reacted with 65.2 +/- 10.9% of the thymocytes and caused a fast plasma membrane disruption. Cells (28.7 +/- 7.1%) were stained with PI after incubation with the hidden antibodies for 1 h. The free antibodies bound to a very small fraction of the thymocytes and did not evoke death as compared to control without antibodies. The possible reason for the observed effects is difference in reactivity of the free and hidden antibodies to phospholipids. While free antibodies reacted preferentially with phosphotidylcholine, hidden antibodies reacted with cardiolipin and phosphotidylserine.
NASA Astrophysics Data System (ADS)
Vokhmyanin, M.; Ponyavin, D. I.
2012-12-01
Interplanetary magnetic field (IMF) polarities can be inferred in the pre-satellite era using Svalgaard-Mansurov effect, according to which different IMF directions lead to different geomagnetic variations at polar stations. Basing on this effect we propose a method to derive a sector structure of the IMF when only ground based data are available. Details of the method and results have been presented in our recent paper: Vokhmyanin, M. V., and D. I. Ponyavin (2012), Inferring interplanetary magnetic field polarities from geomagnetic variations, J. Geophys. Res., 117, A06102, doi:10.1029/2011JA017060. Using data from eight stations: Sitka, Sodankyla, Godhavn, Lerwick, Thule, Baker Lake, Vostok and Mirny, we reconstructed sector structure back to 1905. The quality of inferring from 1965 to 2005 ranges between 78% and 90% depending on the used set of stations. Our results show both high success rate and good agreement with the well-known Russell-McPherron and Rosenberg-Coleman effects. In the current study we applied the technique to historical data of Helsinki observatory where digital versions of hourly geomagnetic components are available from 1844 to 1897. Helsinki station stopped operates at the beginning of 20th century. Thus, to create a model describing the local Svalgaard-Mansurov effect we analyzed data from Nurmijarvi station located near the same region. The success rate of reconstruction from 1965 to 2005 is around 82%. So we assume that the IMF polarities obtained for the period 1869-1889 have sufficient quality. Inferred sector structure at this time consists of two sectors typically for all declining phases of solar activity cycle. Catalogue of IMF proxies seem to be important in analyzing structure and dynamics of solar magnetic fields in the past.; Left: Bartels diagram of IMF sector structure inferred from Helsinki data. Right: sunspot number indicating solar cycles.
Evaluation of the Interplanetary Magnetic Field Strength Using the Cosmic-Ray Shadow of the Sun
NASA Astrophysics Data System (ADS)
Amenomori, M.; Bi, X. J.; Chen, D.; Chen, T. L.; Chen, W. Y.; Cui, S. W.; Danzengluobu, Ding, L. K.; Feng, C. F.; Feng, Zhaoyang; Feng, Z. Y.; Gou, Q. B.; Guo, Y. Q.; He, H. H.; He, Z. T.; Hibino, K.; Hotta, N.; Hu, Haibing; Hu, H. B.; Huang, J.; Jia, H. Y.; Jiang, L.; Kajino, F.; Kasahara, K.; Katayose, Y.; Kato, C.; Kawata, K.; Kozai, M.; Labaciren, Le, G. M.; Li, A. F.; Li, H. J.; Li, W. J.; Liu, C.; Liu, J. S.; Liu, M. Y.; Lu, H.; Meng, X. R.; Miyazaki, T.; Mizutani, K.; Munakata, K.; Nakajima, T.; Nakamura, Y.; Nanjo, H.; Nishizawa, M.; Niwa, T.; Ohnishi, M.; Ohta, I.; Ozawa, S.; Qian, X. L.; Qu, X. B.; Saito, T.; Saito, T. Y.; Sakata, M.; Sako, T. K.; Shao, J.; Shibata, M.; Shiomi, A.; Shirai, T.; Sugimoto, H.; Takita, M.; Tan, Y. H.; Tateyama, N.; Torii, S.; Tsuchiya, H.; Udo, S.; Wang, H.; Wu, H. R.; Xue, L.; Yamamoto, Y.; Yamauchi, K.; Yang, Z.; Yuan, A. F.; Yuda, T.; Zhai, L. M.; Zhang, H. M.; Zhang, J. L.; Zhang, X. Y.; Zhang, Y.; Zhang, Yi; Zhang, Ying; Zhaxisangzhu, Zhou, X. X.; Tibet AS γ Collaboration
2018-01-01
We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disk center in the "away" ("toward") interplanetary magnetic field (IMF) sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the away (toward) sector is 1.54 ±0.21stat±0.20syst (1.62 ±0.15stat±0.22syst ) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field.
Einstein’s gravity from a polynomial affine model
NASA Astrophysics Data System (ADS)
Castillo-Felisola, Oscar; Skirzewski, Aureliano
2018-03-01
We show that the effective field equations for a recently formulated polynomial affine model of gravity, in the sector of a torsion-free connection, accept general Einstein manifolds—with or without cosmological constant—as solutions. Moreover, the effective field equations are partially those obtained from a gravitational Yang–Mills theory known as Stephenson–Kilmister–Yang theory. Additionally, we find a generalization of a minimally coupled massless scalar field in General Relativity within a ‘minimally’ coupled scalar field in this affine model. Finally, we present a brief (perturbative) analysis of the propagators of the gravitational theory, and count the degrees of freedom. For completeness, we prove that a Birkhoff-like theorem is valid for the analyzed sector.
Evaluation of the Interplanetary Magnetic Field Strength Using the Cosmic-Ray Shadow of the Sun.
Amenomori, M; Bi, X J; Chen, D; Chen, T L; Chen, W Y; Cui, S W; Danzengluobu; Ding, L K; Feng, C F; Feng, Zhaoyang; Feng, Z Y; Gou, Q B; Guo, Y Q; He, H H; He, Z T; Hibino, K; Hotta, N; Hu, Haibing; Hu, H B; Huang, J; Jia, H Y; Jiang, L; Kajino, F; Kasahara, K; Katayose, Y; Kato, C; Kawata, K; Kozai, M; Labaciren; Le, G M; Li, A F; Li, H J; Li, W J; Liu, C; Liu, J S; Liu, M Y; Lu, H; Meng, X R; Miyazaki, T; Mizutani, K; Munakata, K; Nakajima, T; Nakamura, Y; Nanjo, H; Nishizawa, M; Niwa, T; Ohnishi, M; Ohta, I; Ozawa, S; Qian, X L; Qu, X B; Saito, T; Saito, T Y; Sakata, M; Sako, T K; Shao, J; Shibata, M; Shiomi, A; Shirai, T; Sugimoto, H; Takita, M; Tan, Y H; Tateyama, N; Torii, S; Tsuchiya, H; Udo, S; Wang, H; Wu, H R; Xue, L; Yamamoto, Y; Yamauchi, K; Yang, Z; Yuan, A F; Yuda, T; Zhai, L M; Zhang, H M; Zhang, J L; Zhang, X Y; Zhang, Y; Zhang, Yi; Zhang, Ying; Zhaxisangzhu; Zhou, X X
2018-01-19
We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disk center in the "away" ("toward") interplanetary magnetic field (IMF) sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the away (toward) sector is 1.54±0.21_{stat}±0.20_{syst} (1.62±0.15_{stat}±0.22_{syst}) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field.
Classification of Arnold-Beltrami flows and their hidden symmetries
NASA Astrophysics Data System (ADS)
Fré, P.; Sorin, A. S.
2015-07-01
In the context of mathematical hydrodynamics, we consider the group theory structure which underlies the so named ABC flows introduced by Beltrami, Arnold and Childress. Main reference points are Arnold's theorem stating that, for flows taking place on compact three manifolds ℳ3, the only velocity fields able to produce chaotic streamlines are those satisfying Beltrami equation and the modern topological conception of contact structures, each of which admits a representative contact one-form also satisfying Beltrami equation. We advocate that Beltrami equation is nothing else but the eigenstate equation for the first order Laplace-Beltrami operator ★ g d, which can be solved by using time-honored harmonic analysis. Taking for ℳ3, a torus T 3 constructed as ℝ3/Λ, where Λ is a crystallographic lattice, we present a general algorithm to construct solutions of the Beltrami equation which utilizes as main ingredient the orbits under the action of the point group B A of three-vectors in the momentum lattice *Λ. Inspired by the crystallographic construction of space groups, we introduce the new notion of a Universal Classifying Group which contains all space groups as proper subgroups. We show that the ★ g d eigenfunctions are naturally arranged into irreducible representations of and by means of a systematic use of the branching rules with respect to various possible subgroups we search and find Beltrami fields with non trivial hidden symmetries. In the case of the cubic lattice the point group is the proper octahedral group O24 and the Universal Classifying Group is a finite group G1536 of order |G1536| = 1536 which we study in full detail deriving all of its 37 irreducible representations and the associated character table. We show that the O24 orbits in the cubic lattice are arranged into 48 equivalence classes, the parameters of the corresponding Beltrami vector fields filling all the 37 irreducible representations of G1536. In this way we obtain an exhaustive classification of all generalized ABC- flows and of their hidden symmetries. We make several conceptual comments about the need of a field-theory yielding Beltrami equation as a field equation and/or an instanton equation and on the possible relation of Arnold-Beltrami flows with (supersymmetric) Chern-Simons gauge theories. We also suggest linear generalizations of Beltrami equation to higher odd-dimensions that are different from the non-linear one proposed by Arnold and possibly make contact with M-theory and the geometry of flux-compactifications.
Fractional and hidden magnetic excitations in f-electron metal Yb2Pt2Pb
NASA Astrophysics Data System (ADS)
Zaliznyak, Igor
Quantum states with fractionalized excitations such as spinons in one-dimensional chains are commonly viewed as belonging to the domain of S=1/2 spin systems. However, recent experiments on the quantum antiferromagnet Yb2Pt2Pb, part of a large family of R2T2X (R=rare earth, T=transition metal, X=main group) materials spectacularly disqualify this opinion. The results show that spinons can also emerge in an f-electron system with strong spin-orbit coupling, where magnetism is mainly associated with large and anisotropic orbital moment. Here, the competition of several high-energy interactions Coulomb repulsion, spin-orbit coupling, crystal field, and the peculiar crystal structure, which combines low dimensionality and geometrical frustration, lead to the emergence, at low energy, of an effective spin-1/2, purely quantum Hamiltonian. Consequently, it produces unusual spin-liquid states and fractional excitations enabled by the inherently quantum mechanical nature of the moments. The emergent quantum spins bear the unique birthmark of their unusual origin in that they only lead to measurable longitudinal magnetic fluctuations, while the transverse excitations such as spin waves remain invisible to scattering experiments. Similarlyhidden would be transverse magnetic ordering, although it would have visible excitations. The rich magnetic phase diagram of Yb2Pt2Pb is suggestive of the existence of hidden-order phases, while the recent experiments indeed reveal the dark magnon, a hidden excitation in the saturated ferromagnetic (FM) phase of Yb2Pt2Pb. Unlike copper-based spin-1/2 chains, where the magnon in the FM state accounts for the full spectral weight of the zero-field spinon continuum, in the spin-orbital chains in Yb2Pt2Pb it is 100 times, or more weaker. It thus presents an example of dark magnon matter\\x9D, whose Hamiltonian is that of the effective spin-1/2 chain, but whose coupling to magnetic field, the physical probe at our disposal, is vanishingly small. The work was supported by the Office of Basic Energy Sciences, U.S. Department of Energy, under Contract No. DE-SC00112704, and by by NSF-DMR-1310008.
2008-01-01
with many private sector companies to manufacture, field , and develop the products it acquires. As mentioned, the percentages of work outsourced ...been involved from the conceptual development all the way to operational testing and fielding of every major weapons system our Marines and Sailors...the ability to collaborate with contractors and assess the defense value of private sector technologi- cal developments . The inherently governmental
Heating up the Galaxy with hidden photons
DOE Office of Scientific and Technical Information (OSTI.GOV)
Dubovsky, Sergei; Hernández-Chifflet, Guzmán, E-mail: dubovsky@nyu.edu, E-mail: ghc236@nyu.edu
2015-12-01
We elaborate on the dynamics of ionized interstellar medium in the presence of hidden photon dark matter. Our main focus is the ultra-light regime, where the hidden photon mass is smaller than the plasma frequency in the Milky Way. We point out that as a result of the Galactic plasma shielding direct detection of ultra-light photons in this mass range is especially challenging. However, we demonstrate that ultra-light hidden photon dark matter provides a powerful heating source for the ionized interstellar medium. This results in a strong bound on the kinetic mixing between hidden and regular photons all the waymore » down to the hidden photon masses of order 10{sup −20} eV.« less
Heating up the Galaxy with hidden photons
DOE Office of Scientific and Technical Information (OSTI.GOV)
Dubovsky, Sergei; Hernández-Chifflet, Guzmán; Instituto de Física, Facultad de Ingeniería, Universidad de la República,Montevideo, 11300
2015-12-29
We elaborate on the dynamics of ionized interstellar medium in the presence of hidden photon dark matter. Our main focus is the ultra-light regime, where the hidden photon mass is smaller than the plasma frequency in the Milky Way. We point out that as a result of the Galactic plasma shielding direct detection of ultra-light photons in this mass range is especially challenging. However, we demonstrate that ultra-light hidden photon dark matter provides a powerful heating source for the ionized interstellar medium. This results in a strong bound on the kinetic mixing between hidden and regular photons all the waymore » down to the hidden photon masses of order 10{sup −20} eV.« less
NASA Astrophysics Data System (ADS)
Elya, N.; Shoimah, F.; Kartika, A. P.; Sukanto, A. B.
2017-06-01
Hulu Sungai Selatan Regency has a potential of SMI (Small and Medium Industries) sectors can be developed as economic development. Based on RTRW of Hulu Sungai Selatan Regency, the region has 14 SMI are a propeller, pottery, blacksmith, dried fish, purun webbing, pastries, dodol, crackers, imitation jewelry, woven water hyacinth, bamboo, syrup, brown sugar, and saber. There are several issues related to SMI development such as low quality and quantity of human resources, local raw material, limited capital, low competitiveness, conventional production equipment, and lack of media for marketing the product. The purpose of this study is to develop the leading sectors of SMI and improve the economy and quality of the resident. The research method is descriptive qualitative, leading sectors analysis and force field analysis. Data were obtained from primary and secondary survey of relevant institutions and interview to the community. Based on leading sectors analysis, there is six leading sector is a propeller, blacksmith, dodol, dried fish, pottery, and crackers. Based on force field analysis, determined the strategy for using operational excellence’s concept, so that we can develop the industrial sector by minimizing productions cost so SMI’s product can compete by the price and efficient production process.
NASA Astrophysics Data System (ADS)
Mukhopadhyay, Partha
2007-06-01
We discuss a universality property of any covariant field theory in space-time expanded around pp-wave backgrounds. According to this property the space-time lagrangian density evaluated on a restricted set of field configurations, called universal sector, turns out to be same around all the pp-waves, even off-shell, with same transverse space and same profiles for the background scalars. In this paper we restrict our discussion to tensorial fields only. In the context of bosonic string theory we consider on-shell pp-waves and argue that universality requires the existence of a universal sector of world-sheet operators whose correlation functions are insensitive to the pp-wave nature of the metric and the background gauge flux. Such results can also be reproduced using the world-sheet conformal field theory. We also study such pp-waves in non-polynomial closed string field theory (CSFT). In particular, we argue that for an off-shell pp-wave ansatz with flat transverse space and dilaton independent of transverse coordinates the field redefinition relating the low energy effective field theory and CSFT with all the massive modes integrated out is at most quadratic in fields. Because of this simplification it is expected that the off-shell pp-waves can be identified on the two sides. Furthermore, given the massless pp-wave field configurations, an iterative method for computing the higher massive modes using the CSFT equations of motion has been discussed. All our bosonic string theory analyses can be generalised to the common Neveu-Schwarz sector of superstrings.
Naghizadeh, Farzaneh; Garas, Anita; Vargha, Péter; Holló, Gábor
2014-01-01
To determine structure-function relationship between each of 16 Octopus perimeter G2 program clusters and the corresponding 16 peripapillary sector retinal nerve fiber layer thickness (RNFLT) values measured with the RTVue-100 Fourier-domain optical coherence tomography (RTVue OCT) and scanning laser polarimetry with variable corneal compensation (GDx-VCC) and enhanced corneal compensation (GDx-ECC) corneal compensation. One eye of 110 white patients (15 healthy, 20 ocular hypertensive, and 75 glaucoma eyes) were investigated. The Akaike information criterion and the F test were used to identify the best fitting model. Parabolic relationship with logarithmic cluster mean sensitivity and linear sector RNFLT values provided the best fit. For RTVue OCT, significant (P<0.0001) coefficients of determination (R) were found for all 16 RNFLT sectors. The R values were highest for the temporal, superotemporal, and inferotemporal RNFLT sectors (0.4483 to 0.5186). For GDx-VCC/ECC, significant (P<0.01) parabolic relationship was seen for all but the temporal and nasal RNFLT sectors. The overall highest R value (0.6943) was found for a superotemporal RNFLT sector with GDx-ECC. For some RNFLT sectors, the goodness of fit differed significantly between the imaging methods. Structure-function relationship was similar for the total population and the glaucoma subgroup, whereas no relationship (P>0.05) was found for the control eyes. Mean sensitivity of the Octopus visual field clusters showed significant parabolic relationship with the corresponding peripapillary RNFLT sectors. The relationship was more general with the RTVue OCT than GDx-VCC or GDx-ECC. The results show that visual field clusters of the Octopus G program can be applied for detailed structure-function research.
On the average configuration of the geomagnetic tail
NASA Technical Reports Server (NTRS)
Fairfield, D. H.
1978-01-01
Over 3000 hours of IMP-6 magnetic field data obtained between 20 and 33 R sub E in the geomagnetic tail have been used in a statistical study of the tail configuration. A distribution of 2.5 minute averages of B sub Z as a function of position across the tail reveals that more flux crosses the equatorial plane near the dawn and dusk flanks than near midnight. The tail field projected in the solar magnetospheric equatorial plane deviates from the X axis due to flaring and solar wind aberration by an angle alpha = -0.9 y sub SM - 1.7 where Y sub SM is in earth radii and alpha is in degrees. After removing these effects the Y component of the tail field is found to depend on interplanetary sector structure. During an away sector the B sub Y component of the tail field is on average 0.5 gamma greater than that during a toward sector, a result that is true in both tail lobes and is independent of location across the tail.
Macroscopic theory of dark sector
NASA Astrophysics Data System (ADS)
Meierovich, Boris
A simple Lagrangian with squared covariant divergence of a vector field as a kinetic term turned out an adequate tool for macroscopic description of the dark sector. The zero-mass field acts as the dark energy. Its energy-momentum tensor is a simple additive to the cosmological constant [1]. Space-like and time-like massive vector fields describe two different forms of dark matter. The space-like massive vector field is attractive. It is responsible for the observed plateau in galaxy rotation curves [2]. The time-like massive field displays repulsive elasticity. In balance with dark energy and ordinary matter it provides a four parametric diversity of regular solutions of the Einstein equations describing different possible cosmological and oscillating non-singular scenarios of evolution of the universe [3]. In particular, the singular big bang turns into a regular inflation-like transition from contraction to expansion with the accelerate expansion at late times. The fine-tuned Friedman-Robertson-Walker singular solution corresponds to the particular limiting case at the boundary of existence of regular oscillating solutions in the absence of vector fields. The simplicity of the general covariant expression for the energy-momentum tensor allows to analyse the main properties of the dark sector analytically and avoid unnecessary model assumptions. It opens a possibility to trace how the additional attraction of the space-like dark matter, dominating in the galaxy scale, transforms into the elastic repulsion of the time-like dark matter, dominating in the scale of the Universe. 1. B. E. Meierovich. "Vector fields in multidimensional cosmology". Phys. Rev. D 84, 064037 (2011). 2. B. E. Meierovich. "Galaxy rotation curves driven by massive vector fields: Key to the theory of the dark sector". Phys. Rev. D 87, 103510, (2013). 3. B. E. Meierovich. "Towards the theory of the evolution of the Universe". Phys. Rev. D 85, 123544 (2012).
The Evolving Private Military Sector: A Survey
2009-08-05
enough evidence (for instance, the diversification of commercial security firms into the PM sector) and enough theory (for instance, institutional ... theory about how new fields are created out of old ones, how legitimacy is co-opted) to suggest this perspective might warrant further investigation
Modified Mahalanobis Taguchi System for Imbalance Data Classification
2017-01-01
The Mahalanobis Taguchi System (MTS) is considered one of the most promising binary classification algorithms to handle imbalance data. Unfortunately, MTS lacks a method for determining an efficient threshold for the binary classification. In this paper, a nonlinear optimization model is formulated based on minimizing the distance between MTS Receiver Operating Characteristics (ROC) curve and the theoretical optimal point named Modified Mahalanobis Taguchi System (MMTS). To validate the MMTS classification efficacy, it has been benchmarked with Support Vector Machines (SVMs), Naive Bayes (NB), Probabilistic Mahalanobis Taguchi Systems (PTM), Synthetic Minority Oversampling Technique (SMOTE), Adaptive Conformal Transformation (ACT), Kernel Boundary Alignment (KBA), Hidden Naive Bayes (HNB), and other improved Naive Bayes algorithms. MMTS outperforms the benchmarked algorithms especially when the imbalance ratio is greater than 400. A real life case study on manufacturing sector is used to demonstrate the applicability of the proposed model and to compare its performance with Mahalanobis Genetic Algorithm (MGA). PMID:28811820
Vandermoere, Frederic; Blanchemanche, Sandrine; Bieberstein, Andrea; Marette, Stephan; Roosen, Jutta
2011-03-01
In spite of great expectations about the potential of nanotechnology, this study shows that people are rather ambiguous and pessimistic about nanotechnology applications in the food domain. Our findings are drawn from a survey of public perceptions about nanotechnology food and nanotechnology food packaging (N = 752). Multinomial logistic regression analyses further reveal that knowledge about food risks and nanotechnology significantly influences people's views about nanotechnology food packaging. However, knowledge variables were unrelated to support for nanofood, suggesting that an increase in people's knowledge might not be sufficient to bridge the gap between the excitement some business leaders in the food sector have and the restraint of the public. Additionally, opposition to nanofood was not related to the use of heuristics but to trust in governmental agencies. Furthermore, the results indicate that public perceptions of nanoscience in the food domain significantly relate to views on science, technology, and nature.
Cosmology and accelerator tests of strongly interacting dark matter
Berlin, Asher; Blinov, Nikita; Gori, Stefania; ...
2018-03-23
A natural possibility for dark matter is that it is composed of the stable pions of a QCD-like hidden sector. Existing literature largely assumes that pion self-interactions alone control the early universe cosmology. We point out that processes involving vector mesons typically dominate the physics of dark matter freeze-out and significantly widen the viable mass range for these models. The vector mesons also give rise to striking signals at accelerators. For example, in most of the cosmologically favored parameter space, the vector mesons are naturally long-lived and produce standard model particles in their decays. Electron and proton beam fixed-target experimentsmore » such as HPS, SeaQuest, and LDMX can exploit these signals to explore much of the viable parameter space. As a result, we also comment on dark matter decay inherent in a large class of previously considered models and explain how to ensure dark matter stability.« less
Davoudiasl, Hooman; Hooper, Dan; McDermott, Samuel D
2016-01-22
We describe a general scenario, dubbed "inflatable dark matter," in which the density of dark matter particles can be reduced through a short period of late-time inflation in the early Universe. The overproduction of dark matter that is predicted within many, otherwise, well-motivated models of new physics can be elegantly remedied within this context. Thermal relics that would, otherwise, be disfavored can easily be accommodated within this class of scenarios, including dark matter candidates that are very heavy or very light. Furthermore, the nonthermal abundance of grand unified theory or Planck scale axions can be brought to acceptable levels without invoking anthropic tuning of initial conditions. A period of late-time inflation could have occurred over a wide range of scales from ∼MeV to the weak scale or above, and could have been triggered by physics within a hidden sector, with small but not necessarily negligible couplings to the standard model.
Axial vector Z‧ and anomaly cancellation
NASA Astrophysics Data System (ADS)
Ismail, Ahmed; Keung, Wai-Yee; Tsao, Kuo-Hsing; Unwin, James
2017-05-01
Whilst the prospect of new Z‧ gauge bosons with only axial couplings to the Standard Model (SM) fermions is widely discussed, examples of anomaly-free renormalisable models are lacking in the literature. We look to remedy this by constructing several motivated examples. Specifically, we consider axial vectors which couple universally to all SM fermions, as well as those which are generation-specific, leptophilic, and leptophobic. Anomaly cancellation typically requires the presence of new coloured and charged chiral fermions, and we argue that in a large class of models masses of these new states are expected to be comparable to that of the axial vector. Finally, an axial vector mediator could provide a portal between SM and hidden sector states, and we also consider the possibility that the axial vector couples to dark matter. If the dark matter relic density is set due to freeze-out via the axial vector, this strongly constrains the parameter space.
Cosmology and accelerator tests of strongly interacting dark matter
NASA Astrophysics Data System (ADS)
Berlin, Asher; Blinov, Nikita; Gori, Stefania; Schuster, Philip; Toro, Natalia
2018-03-01
A natural possibility for dark matter is that it is composed of the stable pions of a QCD-like hidden sector. Existing literature largely assumes that pion self-interactions alone control the early universe cosmology. We point out that processes involving vector mesons typically dominate the physics of dark matter freeze-out and significantly widen the viable mass range for these models. The vector mesons also give rise to striking signals at accelerators. For example, in most of the cosmologically favored parameter space, the vector mesons are naturally long-lived and produce standard model particles in their decays. Electron and proton beam fixed-target experiments such as HPS, SeaQuest, and LDMX can exploit these signals to explore much of the viable parameter space. We also comment on dark matter decay inherent in a large class of previously considered models and explain how to ensure dark matter stability.
Cosmology and accelerator tests of strongly interacting dark matter
DOE Office of Scientific and Technical Information (OSTI.GOV)
Berlin, Asher; Blinov, Nikita; Gori, Stefania
A natural possibility for dark matter is that it is composed of the stable pions of a QCD-like hidden sector. Existing literature largely assumes that pion self-interactions alone control the early universe cosmology. We point out that processes involving vector mesons typically dominate the physics of dark matter freeze-out and significantly widen the viable mass range for these models. The vector mesons also give rise to striking signals at accelerators. For example, in most of the cosmologically favored parameter space, the vector mesons are naturally long-lived and produce standard model particles in their decays. Electron and proton beam fixed-target experimentsmore » such as HPS, SeaQuest, and LDMX can exploit these signals to explore much of the viable parameter space. As a result, we also comment on dark matter decay inherent in a large class of previously considered models and explain how to ensure dark matter stability.« less
Compacted dimensions and singular plasmonic surfaces
NASA Astrophysics Data System (ADS)
Pendry, J. B.; Huidobro, Paloma Arroyo; Luo, Yu; Galiffi, Emanuele
2017-11-01
In advanced field theories, there can be more than four dimensions to space, the excess dimensions described as compacted and unobservable on everyday length scales. We report a simple model, unconnected to field theory, for a compacted dimension realized in a metallic metasurface periodically structured in the form of a grating comprising a series of singularities. An extra dimension of the grating is hidden, and the surface plasmon excitations, though localized at the surface, are characterized by three wave vectors rather than the two of typical two-dimensional metal grating. We propose an experimental realization in a doped graphene layer.
"It's Not Always What It Seems": Exploring the Hidden Curriculum within a Doctoral Program
ERIC Educational Resources Information Center
Foot, Rachel Elizabeth
2017-01-01
The purpose of this qualitative, naturalistic study was to explore the ways in which hidden curriculum might influence doctoral student success. Two questions guided the study: (a) How do doctoral students experience the hidden curriculum? (b) What forms of hidden curricula can be identified in a PhD program? Data were collected from twelve…
Doja, Asif; Bould, M Dylan; Clarkin, Chantalle; Eady, Kaylee; Sutherland, Stephanie; Writer, Hilary
2016-04-01
The hidden and informal curricula refer to learning in response to unarticulated processes and constraints, falling outside the formal medical curriculum. The hidden curriculum has been identified as requiring attention across all levels of learning. We sought to assess the knowledge and perceptions of the hidden and informal curricula across the continuum of learning at a single institution. Focus groups were held with undergraduate and postgraduate learners and faculty to explore knowledge and perceptions relating to the hidden and informal curricula. Thematic analysis was conducted both inductively by research team members and deductively using questions structured by the existing literature. Participants highlighted several themes related to the presence of the hidden and informal curricula in medical training and practice, including: the privileging of some specialties over others; the reinforcement of hierarchies within medicine; and a culture of tolerance towards unprofessional behaviors. Participants acknowledged the importance of role modeling in the development of professional identities and discussed the deterioration in idealism that occurs. Common issues pertaining to the hidden curriculum exist across all levels of learners, including faculty. Increased awareness of these issues could allow for the further development of methods to address learning within the hidden curriculum.
Doja, Asif; Bould, M Dylan; Clarkin, Chantalle; Eady, Kaylee; Sutherland, Stephanie; Writer, Hilary
2016-01-01
The hidden and informal curricula refer to learning in response to unarticulated processes and constraints, falling outside the formal medical curriculum. The hidden curriculum has been identified as requiring attention across all levels of learning. We sought to assess the knowledge and perceptions of the hidden and informal curricula across the continuum of learning at a single institution. Focus groups were held with undergraduate and postgraduate learners and faculty to explore knowledge and perceptions relating to the hidden and informal curricula. Thematic analysis was conducted both inductively by research team members and deductively using questions structured by the existing literature. Participants highlighted several themes related to the presence of the hidden and informal curricula in medical training and practice, including: the privileging of some specialties over others; the reinforcement of hierarchies within medicine; and a culture of tolerance towards unprofessional behaviors. Participants acknowledged the importance of role modeling in the development of professional identities and discussed the deterioration in idealism that occurs. Common issues pertaining to the hidden curriculum exist across all levels of learners, including faculty. Increased awareness of these issues could allow for the further development of methods to address learning within the hidden curriculum.
Hidden Farmworker Labor Camps in North Carolina: An Indicator of Structural Vulnerability
Summers, Phillip; Quandt, Sara A.; Talton, Jennifer W.; Galván, Leonardo
2015-01-01
Objectives. We used geographic information systems (GIS) to delineate whether farmworker labor camps were hidden and to determine whether hidden camps differed from visible camps in terms of physical and resident characteristics. Methods. We collected data using observation, interview, and public domain GIS data for 180 farmworker labor camps in east central North Carolina. A hidden camp was defined as one that was at least 0.15 miles from an all-weather road or located behind natural or manufactured objects. Hidden camps were compared with visible camps in terms of physical and resident characteristics. Results. More than one third (37.8%) of the farmworker labor camps were hidden. Hidden camps were significantly larger (42.7% vs 17.0% with 21 or more residents; P ≤ .001; and 29.4% vs 13.5% with 3 or more dwellings; P = .002) and were more likely to include barracks (50% vs 19.6%; P ≤ .001) than were visible camps. Conclusions. Poor housing conditions in farmworker labor camps often go unnoticed because they are hidden in the rural landscape, increasing farmworker vulnerability. Policies that promote greater community engagement with farmworker labor camp residents to reduce structural vulnerability should be considered. PMID:26469658
NASA Astrophysics Data System (ADS)
Huang, Tao; Lühr, Hermann; Wang, Hui; Xiong, Chao
2017-12-01
The relationship between high-latitude ionospheric currents (Hall current and field-aligned current) and thermospheric wind is investigated. The 2-D patterns of horizontal wind and equivalent current in the Northern Hemisphere derived from the CHAMP satellite are considered for the first time simultaneously. The equivalent currents show strong dependences on both interplanetary magnetic field (IMF) By and Bz components. However, IMF By orientation is more important in controlling the wind velocity patterns. The duskside wind vortex as well as the antisunward wind in the morning polar cap is more evident for positive By. To better understand their spatial relation in different sectors, a systematic superposed epoch analysis is applied. Our results show that in the dusk sector, the vectors of the zonal wind and equivalent current are anticorrelated, and both of them form a vortical flow pattern for different activity levels. The currents and zonal wind are intensified with the increase of merging electric field. However, on the dawnside, where the relation is less clear, antisunward zonal winds dominate. Plasma drift seems to play a less important role for the wind than neutral forces in this sector. In the noon sector, the best anticorrelation between equivalent current and wind is observed for a positive IMF By component and it is less obvious for negative By. A clear seasonal effect with current intensities increasing from winter to summer is observed in the noon sector. Different from the currents, the zonal wind intensity shows little dependence on seasons. Our results indicate that the plasma drift and the neutral forces are of comparable influence on the zonal wind at CHAMP altitude in the noon sector.
Influence of interplanetary solar wind sector polarity on the ionosphere
NASA Astrophysics Data System (ADS)
liu, jing
2014-05-01
Knowledge of solar sector polarity effects on the ionosphere may provide some clues in understanding of the ionospheric day-to-day variability. A solar-terrestrial connection ranging from solar sector boundary (SB) crossings, geomagnetic disturbance and ionospheric perturbations has been demonstrated. The increases in interplanetary solar wind speed within three days are seen after SB crossings, while the decreases in solar wind dynamic pressure and magnetic field intensity immediately after SB crossings are confirmed by the superposed epoch analysis results. Furthermore, the interplanetary magnetic field (IMF) Bz component turns from northward to southward in March equinox and June solstice as the Earth passes from a solar sector of outward to inward directed magnetic fields, whereas the reverse situation occurs for the transition from toward to away sectors. The F2 region critical frequency (foF2) covering about four solar cycles and total electron content (TEC) during 1998-2011 are utilized to extract the related information, revealing that they are not modified significantly and vary within the range of 15% on average. The responses of the ionospheric TEC to SB crossings exhibit complex temporal and spatial variations and have strong dependencies on season, latitude, and solar cycle. This effect is more appreciable in equinoctial months than in solstitial months, which is mainly caused by larger southward Bz components in equinox. In September equinox, latitudinal profile of relative variations of foF2 at noon is featured by depressions at high latitudes and enhancements in low-equatorial latitudes during IMF away sectors. The negative phase of foF2 is delayed at solar minimum relative to it during other parts of solar cycle, which might be associated with the difference in longevity of major interplanetary solar wind drivers perturbing the Earth's environment in different phases of solar cycle.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Levi, Michele; Steinhoff, Jan, E-mail: michele.levi@upmc.fr, E-mail: jan.steinhoff@aei.mpg.de
2016-01-01
The next-to-next-to-leading order spin-squared interaction potential for generic compact binaries is derived for the first time via the effective field theory for gravitating spinning objects in the post-Newtonian scheme. The spin-squared sector is an intricate one, as it requires the consideration of the point particle action beyond minimal coupling, and mainly involves the spin-squared worldline couplings, which are quite complex, compared to the worldline couplings from the minimal coupling part of the action. This sector also involves the linear in spin couplings, as we go up in the nonlinearity of the interaction, and in the loop order. Hence, there ismore » an excessive increase in the number of Feynman diagrams, of which more are higher loop ones. We provide all the Feynman diagrams and their values. The beneficial ''nonrelativistic gravitational'' fields are employed in the computation. This spin-squared correction, which enters at the fourth post-Newtonian order for rapidly rotating compact objects, completes the conservative sector up to the fourth post-Newtonian accuracy. The robustness of the effective field theory for gravitating spinning objects is shown here once again, as demonstrated in a recent series of papers by the authors, which obtained all spin dependent sectors, required up to the fourth post-Newtonian accuracy. The effective field theory of spinning objects allows to directly obtain the equations of motion, and the Hamiltonians, and these will be derived for the potential obtained here in a forthcoming paper.« less
Pre-relaxation in weakly interacting models
NASA Astrophysics Data System (ADS)
Bertini, Bruno; Fagotti, Maurizio
2015-07-01
We consider time evolution in models close to integrable points with hidden symmetries that generate infinitely many local conservation laws that do not commute with one another. The system is expected to (locally) relax to a thermal ensemble if integrability is broken, or to a so-called generalised Gibbs ensemble if unbroken. In some circumstances expectation values exhibit quasi-stationary behaviour long before their typical relaxation time. For integrability-breaking perturbations, these are also called pre-thermalisation plateaux, and emerge e.g. in the strong coupling limit of the Bose-Hubbard model. As a result of the hidden symmetries, quasi-stationarity appears also in integrable models, for example in the Ising limit of the XXZ model. We investigate a weak coupling limit, identify a time window in which the effects of the perturbations become significant and solve the time evolution through a mean-field mapping. As an explicit example we study the XYZ spin-\\frac{1}{2} chain with additional perturbations that break integrability. One of the most intriguing results of the analysis is the appearance of persistent oscillatory behaviour. To unravel its origin, we study in detail a toy model: the transverse-field Ising chain with an additional nonlocal interaction proportional to the square of the transverse spin per unit length (2013 Phys. Rev. Lett. 111 197203). Despite being nonlocal, this belongs to a class of models that emerge as intermediate steps of the mean-field mapping and shares many dynamical properties with the weakly interacting models under consideration.
Social Work-Business Sector Collaboration in Pursuit of Economic Justice.
Lee, Wonhyung
2016-07-01
This article examines social workers' perceptions, experiences, and prospects regarding working in the business sector after participating in an MSW field practicum with a local microlending program. Social workers' insights suggest that cross-sector collaboration leads to vast opportunities not only for the populations served by the collaborative efforts, but also for social work as a profession. However, several challenges are evealed, including social workers' unfamiliarity with business operations, the business sector's narrow understanding of social workers' roles, and divisions between participants in interprofessional collaboration. This article calls for enhancing the role of social work to maximize its impact on economic development through further research and tangible cross-sector projects.
Public health finance: a conceptual framework.
Moulton, Anthony D; Halverson, Paul K; Honoré, Peggy A; Berkowitz, Bobbie
2004-01-01
In an attempt to stimulate development of public health finance as a field of practice, policy, and scholarship, this article proposes a working definition of the term "public health finance," embeds it in the context of the maturing literature on the public health system and its infrastructure, and proposes a four-part typology that spans both public-sector and private-sector contributions to the financing of prevention and health promotion. A developmental strategy for the field--in applied research, training and education, and performance standards--is outlined as well.
Zipf exponent of trajectory distribution in the hidden Markov model
NASA Astrophysics Data System (ADS)
Bochkarev, V. V.; Lerner, E. Yu
2014-03-01
This paper is the first step of generalization of the previously obtained full classification of the asymptotic behavior of the probability for Markov chain trajectories for the case of hidden Markov models. The main goal is to study the power (Zipf) and nonpower asymptotics of the frequency list of trajectories of hidden Markov frequencys and to obtain explicit formulae for the exponent of the power asymptotics. We consider several simple classes of hidden Markov models. We prove that the asymptotics for a hidden Markov model and for the corresponding Markov chain can be essentially different.
Progress and achievements of R&D activities for the ITER vacuum vessel
NASA Astrophysics Data System (ADS)
Nakahira, M.; Takahashi, H.; Koizumi, K.; Onozuka, M.; Ioki, K.
2001-04-01
The Full Scale Sector Model Project, which was initiated in 1995 as one of the Seven Large Projects for ITER R&D, has been continued with the joint effort of the ITER Joint Central Team and the Japanese, Russian Federation and United States Home Teams. The fabrication of a full scale 18° toroidal sector, which is composed of two 9° sectors spliced at the port centre, was successfully completed in September 1997 with a dimensional accuracy of +/-3 mm for the total height and total width. Both sectors were shipped to the test site at the Japan Atomic Energy Research Institute and the integration test of the sectors was begun in October 1997. The integration test involves the adjustment of field joints, automatic narrow gap tungsten inert gas welding of field joints with splice plates and inspection of the joints by ultrasonic testing, as required for the initial assembly of the ITER vacuum vessel. This first demonstration of field joint welding and the performance test of the mechanical characteristics were completed in May 1998, and all the results obtained have satisfied the ITER design. In addition to these tests, integration with the midplane port extension fabricated by the Russian Home Team by using a fully remotized welding and cutting system developed by the US Home Team was completed in March 2000. The article describes the progress, achievements and latest status of the R&D activities for the ITER vacuum vessel.
Separation of internal and external fields: A new technique of data screening. [MAGSAT data
NASA Technical Reports Server (NTRS)
Lemouel, J. L. (Principal Investigator); Menvielle, M.; Ducruix, J.
1980-01-01
A method for eliminating transient variation from MAGSAT data is described. Instead of using the conventional Kp index, the Km index is used for the rejection of nonquiet data. To build the Km index, the surface of the Earth is divided in eight sectors. Each sector is defined by two or three magnetic observatories and its geographic limits. For each three hourly interval the MAGSAT tracks were drawn on a map showing the location of the station (the crosses), the limits of the sector, and the value of the mean K index inside each sector. No figure in a sector means that the activity level in this sector is lower than 5 nt; in a sector covered with number 1, the activity lies between 5 and 20 nt; 2 stands for any level greater than 20 nT.
29 CFR 1952.383 - Completion of developmental steps and certification.
Code of Federal Regulations, 2010 CFR
2010-07-01
..., March, 1978. (g) Adopt the Field Operations Manual, April, 1980. (h) Adopt management information system... plan personnel by March, 1978. (b) Public information program (private sector), one year after plan..., August, 1978. (k) Public information program (government sector), February, 1980. (l) Analysis for...
Confocal non-line-of-sight imaging based on the light-cone transform
NASA Astrophysics Data System (ADS)
O’Toole, Matthew; Lindell, David B.; Wetzstein, Gordon
2018-03-01
How to image objects that are hidden from a camera’s view is a problem of fundamental importance to many fields of research, with applications in robotic vision, defence, remote sensing, medical imaging and autonomous vehicles. Non-line-of-sight (NLOS) imaging at macroscopic scales has been demonstrated by scanning a visible surface with a pulsed laser and a time-resolved detector. Whereas light detection and ranging (LIDAR) systems use such measurements to recover the shape of visible objects from direct reflections, NLOS imaging reconstructs the shape and albedo of hidden objects from multiply scattered light. Despite recent advances, NLOS imaging has remained impractical owing to the prohibitive memory and processing requirements of existing reconstruction algorithms, and the extremely weak signal of multiply scattered light. Here we show that a confocal scanning procedure can address these challenges by facilitating the derivation of the light-cone transform to solve the NLOS reconstruction problem. This method requires much smaller computational and memory resources than previous reconstruction methods do and images hidden objects at unprecedented resolution. Confocal scanning also provides a sizeable increase in signal and range when imaging retroreflective objects. We quantify the resolution bounds of NLOS imaging, demonstrate its potential for real-time tracking and derive efficient algorithms that incorporate image priors and a physically accurate noise model. Additionally, we describe successful outdoor experiments of NLOS imaging under indirect sunlight.
Radar HRRP Target Recognition Based on Stacked Autoencoder and Extreme Learning Machine
Liu, Yongxiang; Huo, Kai; Zhang, Zhongshuai
2018-01-01
A novel radar high-resolution range profile (HRRP) target recognition method based on a stacked autoencoder (SAE) and extreme learning machine (ELM) is presented in this paper. As a key component of deep structure, the SAE does not only learn features by making use of data, it also obtains feature expressions at different levels of data. However, with the deep structure, it is hard to achieve good generalization performance with a fast learning speed. ELM, as a new learning algorithm for single hidden layer feedforward neural networks (SLFNs), has attracted great interest from various fields for its fast learning speed and good generalization performance. However, ELM needs more hidden nodes than conventional tuning-based learning algorithms due to the random set of input weights and hidden biases. In addition, the existing ELM methods cannot utilize the class information of targets well. To solve this problem, a regularized ELM method based on the class information of the target is proposed. In this paper, SAE and the regularized ELM are combined to make full use of their advantages and make up for each of their shortcomings. The effectiveness of the proposed method is demonstrated by experiments with measured radar HRRP data. The experimental results show that the proposed method can achieve good performance in the two aspects of real-time and accuracy, especially when only a few training samples are available. PMID:29320453
Radar HRRP Target Recognition Based on Stacked Autoencoder and Extreme Learning Machine.
Zhao, Feixiang; Liu, Yongxiang; Huo, Kai; Zhang, Shuanghui; Zhang, Zhongshuai
2018-01-10
A novel radar high-resolution range profile (HRRP) target recognition method based on a stacked autoencoder (SAE) and extreme learning machine (ELM) is presented in this paper. As a key component of deep structure, the SAE does not only learn features by making use of data, it also obtains feature expressions at different levels of data. However, with the deep structure, it is hard to achieve good generalization performance with a fast learning speed. ELM, as a new learning algorithm for single hidden layer feedforward neural networks (SLFNs), has attracted great interest from various fields for its fast learning speed and good generalization performance. However, ELM needs more hidden nodes than conventional tuning-based learning algorithms due to the random set of input weights and hidden biases. In addition, the existing ELM methods cannot utilize the class information of targets well. To solve this problem, a regularized ELM method based on the class information of the target is proposed. In this paper, SAE and the regularized ELM are combined to make full use of their advantages and make up for each of their shortcomings. The effectiveness of the proposed method is demonstrated by experiments with measured radar HRRP data. The experimental results show that the proposed method can achieve good performance in the two aspects of real-time and accuracy, especially when only a few training samples are available.
Ecological approaches to human nutrition.
DeClerck, Fabrice A J; Fanzo, Jessica; Palm, Cheryl; Remans, Roseline
2011-03-01
Malnutrition affects a large number of people throughout the developing world. Approaches to reducing malnutrition rarely focus on ecology and agriculture to simultaneously improve human nutrition and environmental sustainability. However, evidence suggests that interdisciplinary approaches that combine the knowledge bases of these disciplines can serve as a central strategy in alleviating hidden hunger for the world's poorest. To describe the role that ecological knowledge plays in alleviating hidden hunger, considering human nutrition as an overlooked ecosystem service. We review existing literature and propose a framework that expands on earlier work on econutrition. We provide novel evidence from case studies conducted by the authors in western Kenya and propose a framework for interdisciplinary collaboration to alleviate hidden hunger, increase agricultural productivity, and improve environmental sustainability. Our review supports the concept that an integrated approach will impact human nutrition. We provide evidence that increased functional agrobiodiversity can alleviate anemia, and interventions that contribute to environmental sustainability can have both direct and indirect effects on human health and nutritional well-being. Integrated and interdisciplinary approaches are critical to reaching development goals. Ecologists must begin to consider not only how their field can contribute to biodiversity conservation, but also, the relationship between biodiversity and provisioning of nontraditional ecosystem services such as human health. Likewise, nutritionists and agronomists must recognize that many of the solutions to increasing human wellbeing and health can best be achieved by focusing on a healthy environment and the conservation of ecosystem services.
García-Pedrajas, Nicolás; Ortiz-Boyer, Domingo; Hervás-Martínez, César
2006-05-01
In this work we present a new approach to crossover operator in the genetic evolution of neural networks. The most widely used evolutionary computation paradigm for neural network evolution is evolutionary programming. This paradigm is usually preferred due to the problems caused by the application of crossover to neural network evolution. However, crossover is the most innovative operator within the field of evolutionary computation. One of the most notorious problems with the application of crossover to neural networks is known as the permutation problem. This problem occurs due to the fact that the same network can be represented in a genetic coding by many different codifications. Our approach modifies the standard crossover operator taking into account the special features of the individuals to be mated. We present a new model for mating individuals that considers the structure of the hidden layer and redefines the crossover operator. As each hidden node represents a non-linear projection of the input variables, we approach the crossover as a problem on combinatorial optimization. We can formulate the problem as the extraction of a subset of near-optimal projections to create the hidden layer of the new network. This new approach is compared to a classical crossover in 25 real-world problems with an excellent performance. Moreover, the networks obtained are much smaller than those obtained with classical crossover operator.
Confocal non-line-of-sight imaging based on the light-cone transform.
O'Toole, Matthew; Lindell, David B; Wetzstein, Gordon
2018-03-15
How to image objects that are hidden from a camera's view is a problem of fundamental importance to many fields of research, with applications in robotic vision, defence, remote sensing, medical imaging and autonomous vehicles. Non-line-of-sight (NLOS) imaging at macroscopic scales has been demonstrated by scanning a visible surface with a pulsed laser and a time-resolved detector. Whereas light detection and ranging (LIDAR) systems use such measurements to recover the shape of visible objects from direct reflections, NLOS imaging reconstructs the shape and albedo of hidden objects from multiply scattered light. Despite recent advances, NLOS imaging has remained impractical owing to the prohibitive memory and processing requirements of existing reconstruction algorithms, and the extremely weak signal of multiply scattered light. Here we show that a confocal scanning procedure can address these challenges by facilitating the derivation of the light-cone transform to solve the NLOS reconstruction problem. This method requires much smaller computational and memory resources than previous reconstruction methods do and images hidden objects at unprecedented resolution. Confocal scanning also provides a sizeable increase in signal and range when imaging retroreflective objects. We quantify the resolution bounds of NLOS imaging, demonstrate its potential for real-time tracking and derive efficient algorithms that incorporate image priors and a physically accurate noise model. Additionally, we describe successful outdoor experiments of NLOS imaging under indirect sunlight.
ERIC Educational Resources Information Center
Duke, Thomas Scott
2007-01-01
The author reviewed 22 articles published in professional journals related to the field of education that examined the experiences of gay and lesbian teachers and related services personnel. Ten of the 22 articles were legal analyses; five were position papers; four reported the findings of empirical research studies; three were anecdotal reports.…
Airborne hunt for faults in the Portland-Vancouver area
Blakely, Richard J.; Wells, Ray E.; Yelin, Thomas S.; Stauffer, Peter H.; Hendley, James W.
1996-01-01
Geologic hazards in the Portland-Vancouver area include faults entirely hidden by river sediments, vegetation, and urban development. A recent aerial geophysical survey revealed patterns in the Earth's magnetic field that confirm the existence of a previously suspected fault running through Portland. It also indicated that this fault may pose a significant seismic threat. This discovery has enabled the residents of the populous area to better prepare for future earthquakes.
NASA Astrophysics Data System (ADS)
Gaber, Mohamed Medhat; Zaslavsky, Arkady; Krishnaswamy, Shonali
Data mining is concerned with the process of computationally extracting hidden knowledge structures represented in models and patterns from large data repositories. It is an interdisciplinary field of study that has its roots in databases, statistics, machine learning, and data visualization. Data mining has emerged as a direct outcome of the data explosion that resulted from the success in database and data warehousing technologies over the past two decades (Fayyad, 1997,Fayyad, 1998,Kantardzic, 2003).
NASA Astrophysics Data System (ADS)
Mat Jafri, Mohd. Zubir; Abdulbaqi, Hayder Saad; Mutter, Kussay N.; Mustapha, Iskandar Shahrim; Omar, Ahmad Fairuz
2017-06-01
A brain tumour is an abnormal growth of tissue in the brain. Most tumour volume measurement processes are carried out manually by the radiographer and radiologist without relying on any auto program. This manual method is a timeconsuming task and may give inaccurate results. Treatment, diagnosis, signs and symptoms of the brain tumours mainly depend on the tumour volume and its location. In this paper, an approach is proposed to improve volume measurement of brain tumors as well as using a new method to determine the brain tumour location. The current study presents a hybrid method that includes two methods. One method is hidden Markov random field - expectation maximization (HMRFEM), which employs a positive initial classification of the image. The other method employs the threshold, which enables the final segmentation. In this method, the tumour volume is calculated using voxel dimension measurements. The brain tumour location was determined accurately in T2- weighted MRI image using a new algorithm. According to the results, this process was proven to be more useful compared to the manual method. Thus, it provides the possibility of calculating the volume and determining location of a brain tumour.
Dynamic Alignment Models for Neural Coding
Kollmorgen, Sepp; Hahnloser, Richard H. R.
2014-01-01
Recently, there have been remarkable advances in modeling the relationships between the sensory environment, neuronal responses, and behavior. However, most models cannot encompass variable stimulus-response relationships such as varying response latencies and state or context dependence of the neural code. Here, we consider response modeling as a dynamic alignment problem and model stimulus and response jointly by a mixed pair hidden Markov model (MPH). In MPHs, multiple stimulus-response relationships (e.g., receptive fields) are represented by different states or groups of states in a Markov chain. Each stimulus-response relationship features temporal flexibility, allowing modeling of variable response latencies, including noisy ones. We derive algorithms for learning of MPH parameters and for inference of spike response probabilities. We show that some linear-nonlinear Poisson cascade (LNP) models are a special case of MPHs. We demonstrate the efficiency and usefulness of MPHs in simulations of both jittered and switching spike responses to white noise and natural stimuli. Furthermore, we apply MPHs to extracellular single and multi-unit data recorded in cortical brain areas of singing birds to showcase a novel method for estimating response lag distributions. MPHs allow simultaneous estimation of receptive fields, latency statistics, and hidden state dynamics and so can help to uncover complex stimulus response relationships that are subject to variable timing and involve diverse neural codes. PMID:24625448
Lorentz Symmetry Violations from Matter-Gravity Couplings with Lunar Laser Ranging
NASA Astrophysics Data System (ADS)
Bourgoin, A.; Le Poncin-Lafitte, C.; Hees, A.; Bouquillon, S.; Francou, G.; Angonin, M.-C.
2017-11-01
The standard-model extension (SME) is an effective field theory framework aiming at parametrizing any violation to the Lorentz symmetry (LS) in all sectors of physics. In this Letter, we report the first direct experimental measurement of SME coefficients performed simultaneously within two sectors of the SME framework using lunar laser ranging observations. We consider the pure gravitational sector and the classical point-mass limit in the matter sector of the minimal SME. We report no deviation from general relativity and put new realistic stringent constraints on LS violations improving up to 3 orders of magnitude previous estimations.
NASA Astrophysics Data System (ADS)
Alva-Valdivia, L. M.; Agarwal, A.; Caballero-Miranda, C.; García-Amador, B. I.; Morales-Barrera, W.; Rodríguez-Elizarraráz, S.; Rodríguez-Trejo, A.
2017-04-01
Lithological, petromagnetic, paleomagnetic and magnetic fabric studies are employed to determine the flow direction and the location of the source of the, 2.44 to 2.21 Ma, El Castillo ignimbrite in the central-east Mexico. Based on the increasing matrix to pumice ratio and decreasing pumice size, the ignimbrite field is divided into the northwestern, central and south-southeastern sectors. Lithological comparisons among the three sectors reveal that the ignimbrite had flowed from NW to SE, and the source is in the NW part of the study area. Thermomagnetic results concur with the increasing matrix proportions from the proximal to the distal sector. The coercivity and magnetization ratios of the hysteresis parameters are lower in the SE sector than in the NW and central sectors. The dominant flow direction inferred through magnetic fabrics, at most sites, is NW to SE, which coincides with the direction inferred from lithological comparisons. However, at some sites magnetic fabrics demonstrate flow towards ENE or other various directions. The paleomagnetic analysis and field observations reveal that these anomalous directions are a consequence of anticlockwise block rotation and tilting due to normal and lateral faulting in the region.
NASA Astrophysics Data System (ADS)
Shibayeva, Marina; Serebryakova, Yelena; Shalnev, Oleg
2017-10-01
Growing demand to increase the investment volume in modernization and development projects for transport infrastructure define the urgency of the current study. The amount of private sector investments in the field is insufficient to implement the projects for road construction due to their significant capital intensity and long payoff period. The implementation of social significant infrastructure projects on the principles of public-private partnership is one of the key strategic directions of growth for transport facilities. The authors come up with a concept and methodology for modeling the investment and innovation activity in the transport facility construction. Furthermore, there is developed a model to find the balance between public and private sector investments in implementing construction projects for transport infrastructure with involvement of PPP (further - public-private partnership). The suggested concepts aim to improve the efficiency rate of the investment and innovation activity in the field of transport facility construction on the basis of public and private sectors collaboration.
Kontis, Alexios-Patapios; Siassiakos, Konstantinos; Kaimakamis, Georgios; Lazakidou, Athina
2010-01-01
The field of the Laboratory Diagnostics (in vitro), a sector of the field of health services, constitutes an industrial market that includes activities of research, development, production and products distribution that are designated for laboratory use. These products are defined as techno-medical products including various categories of products such as simple medicines, advanced technological systems, etc. Despite the high performance, the enlargement and the increasing trends of the field, it is not recorded the expected progress in the methods and the ways of promotion, trading and supporting of these products in the market. The present paper aims at the investigation of the consumers' opinion and the specification of those services that are possible to be implemented in electronic services and commerce for a strongly competitive advantage for the enterprises of the sector. The analysis of the findings from the Consumer Purchase Decision Centres (CPDC) shows how important it is to implement web-based applications in the proposed services.
NASA Technical Reports Server (NTRS)
Tsurutani, B. T.; Smith, E. J.; Jones, D. E.; Lepping, R. P.; Sibeck, D. G.
1984-01-01
The relationships between the Solar Magnetospheric (SM) y-component of the interplanetary magnetic field (IMF) and the lobe and plasmasheet magnetic fields have been studied for the two ISEE-3 deep tail passes. It is found that for positive sector IMFs, 13 percent of the interplanetary magnetic field penetrates into the aberrated north-dawn and south-dusk lobe quadrants, and about the same amount in the north-dusk and south-dawn lobe quadrants for negative sector IMFs. For the above cases, field penetration is significantly less for opposite polarity IMFs. The former results are generally consistent with open magnetospheric models, but the latter (the lack of response in certain quadrants) are unexplained by theory at this time. If the magnitude of the plasmasheet B(y) fields are related to plasma pressure anisotropies, very small anisotropies of about 1.01 are expected.
A superstring field theory for supergravity
NASA Astrophysics Data System (ADS)
Reid-Edwards, R. A.; Riccombeni, D. A.
2017-09-01
A covariant closed superstring field theory, equivalent to classical tendimensional Type II supergravity, is presented. The defining conformal field theory is the ambitwistor string worldsheet theory of Mason and Skinner. This theory is known to reproduce the scattering amplitudes of Cachazo, He and Yuan in which the scattering equations play an important role and the string field theory naturally incorporates these results. We investigate the operator formalism description of the ambitwsitor string and propose an action for the string field theory of the bosonic and supersymmetric theories. The correct linearised gauge symmetries and spacetime actions are explicitly reproduced and evidence is given that the action is correct to all orders. The focus is on the NeveuSchwarz sector and the explicit description of tree level perturbation theory about flat spacetime. Application of the string field theory to general supergravity backgrounds and the inclusion of the Ramond sector are briefly discussed.
A composite model for the 750 GeV diphoton excess
Harigaya, Keisuke; Nomura, Yasunori
2016-03-14
We study a simple model in which the recently reported 750 GeV diphoton excess arises from a composite pseudo Nambu-Goldstone boson — hidden pion — produced by gluon fusion and decaying into two photons. The model only introduces an extra hidden gauge group at the TeV scale with a vectorlike quark in the bifundamental representation of the hidden and standard model gauge groups. We calculate the masses of all the hidden pions and analyze their experimental signatures and constraints. We find that two colored hidden pions must be near the current experimental limits, and hence are probed in the nearmore » future. We study physics of would-be stable particles — the composite states that do not decay purely by the hidden and standard model gauge dynamics — in detail, including constraints from cosmology. We discuss possible theoretical structures above the TeV scale, e.g. conformal dynamics and supersymmetry, and their phenomenological implications. We also discuss an extension of the minimal model in which there is an extra hidden quark that is singlet under the standard model and has a mass smaller than the hidden dynamical scale. This provides two standard model singlet hidden pions that can both be viewed as diphoton/diboson resonances produced by gluon fusion. We discuss several scenarios in which these (and other) resonances can be used to explain various excesses seen in the LHC data.« less
Selective Transient Cooling by Impulse Perturbations in a Simple Toy Model
NASA Astrophysics Data System (ADS)
Fabrizio, Michele
2018-06-01
We show in a simple exactly solvable toy model that a properly designed impulse perturbation can transiently cool down low-energy degrees of freedom at the expense of high-energy ones that heat up. The model consists of two infinite-range quantum Ising models: one, the high-energy sector, with a transverse field much bigger than the other, the low-energy sector. The finite-duration perturbation is a spin exchange that couples the two Ising models with an oscillating coupling strength. We find a cooling of the low-energy sector that is optimized by the oscillation frequency in resonance with the spin exchange excitation. After the perturbation is turned off, the Ising model with a low transverse field can even develop a spontaneous symmetry breaking despite being initially above the critical temperature.
Electroweak baryogenesis and the standard model effective field theory
NASA Astrophysics Data System (ADS)
de Vries, Jordy; Postma, Marieke; van de Vis, Jorinde; White, Graham
2018-01-01
We investigate electroweak baryogenesis within the framework of the Standard Model Effective Field Theory. The Standard Model Lagrangian is supplemented by dimension-six operators that facilitate a strong first-order electroweak phase transition and provide sufficient CP violation. Two explicit scenarios are studied that are related via the classical equations of motion and are therefore identical at leading order in the effective field theory expansion. We demonstrate that formally higher-order dimension-eight corrections lead to large modifications of the matter-antimatter asymmetry. The effective field theory expansion breaks down in the modified Higgs sector due to the requirement of a first-order phase transition. We investigate the source of the breakdown in detail and show how it is transferred to the CP-violating sector. We briefly discuss possible modifications of the effective field theory framework.
[Bibliometric map of Spain 1996-2004: biomedicine and health sciences].
Méndez-Vásquez, Raúl Isaac; Suñén-Pinyol, Eduard; Cervelló, Rosa; Camí, Jordi
2008-03-01
The study presents the bibliometric analysis of the Spanish scientific output in biomedicine during 1996-2004. This is the last edition of a series of bibliometric studies aimed to characterize the Spanish scientific performance in biomedicine. The analysis was restricted to citable documents for which simple and composite bibliometric indicators were obtained at different aggregation levels: fields, autonomous regions, institutional sectors and research centres. The documents were selected according to the Journal Citation Reports, and were assigned to affiliation centres following an integer counting scheme after an exhaustive normalization of the affiliation addresses. Compared to the period 1994-2002, research activity in biomedicine grew as much as Spain: 8.9% in the number of documents; 22.5% citations; 12.5% citation per document average and 27.2% international cooperation. Besides, biomedicine showed the highest citation per document average compared to other major fields. International cooperation in biomedicine (27.2%) reached the European average. The documents published in international cooperation account for the half of citations to documents in biomedicine. The number of documents and citations belonging to the clinic medicine subfield and to the health sector showed the highest growth. In general, these results reproduce the tendencies described in prior studies. The documents in biomedicine showed a highly asymmetric distribution among institutional sectors, autonomous regions, scientific fields and research centres. The remarkably increase in the output of clinical medicine field and in the health sector could be the consequence of important science policy actions undertaken in these areas in the last years.
NASA Technical Reports Server (NTRS)
Hague, D. S.; Vanderburg, J. D.
1977-01-01
A vehicle geometric definition based upon quadrilateral surface elements to produce realistic pictures of an aerospace vehicle. The PCSYS programs can be used to visually check geometric data input, monitor geometric perturbations, and to visualize the complex spatial inter-relationships between the internal and external vehicle components. PCSYS has two major component programs. The between program, IMAGE, draws a complex aerospace vehicle pictorial representation based on either an approximate but rapid hidden line algorithm or without any hidden line algorithm. The second program, HIDDEN, draws a vehicle representation using an accurate but time consuming hidden line algorithm.
Structure of a financial cross-correlation matrix under attack
NASA Astrophysics Data System (ADS)
Lim, Gyuchang; Kim, SooYong; Kim, Junghwan; Kim, Pyungsoo; Kang, Yoonjong; Park, Sanghoon; Park, Inho; Park, Sang-Bum; Kim, Kyungsik
2009-09-01
We investigate the structure of a perturbed stock market in terms of correlation matrices. For the purpose of perturbing a stock market, two distinct methods are used, namely local and global perturbation. The former involves replacing a correlation coefficient of the cross-correlation matrix with one calculated from two Gaussian-distributed time series while the latter reconstructs the cross-correlation matrix just after replacing the original return series with Gaussian-distributed time series. Concerning the local case, it is a technical study only and there is no attempt to model reality. The term ‘global’ means the overall effect of the replacement on other untouched returns. Through statistical analyses such as random matrix theory (RMT), network theory, and the correlation coefficient distributions, we show that the global structure of a stock market is vulnerable to perturbation. However, apart from in the analysis of inverse participation ratios (IPRs), the vulnerability becomes dull under a small-scale perturbation. This means that these analysis tools are inappropriate for monitoring the whole stock market due to the low sensitivity of a stock market to a small-scale perturbation. In contrast, when going down to the structure of business sectors, we confirm that correlation-based business sectors are regrouped in terms of IPRs. This result gives a clue about monitoring the effect of hidden intentions, which are revealed via portfolios taken mostly by large investors.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bae, Kyu Jung; Baer, Howard; Serce, Hasan
Supersymmetric models with radiatively-driven electroweak naturalness require light higgsinos of mass ∼ 100–300 GeV . Naturalness in the QCD sector is invoked via the Peccei-Quinn (PQ) axion leading to mixed axion-higgsino dark matter. The SUSY DFSZ axion model provides a solution to the SUSY μ problem and the Little Hierarchy μ|| m{sub 3/2} may emerge as a consequence of a mismatch between PQ and hidden sector mass scales. The traditional gravitino problem is now augmented by the axino and saxion problems, since these latter particles can also contribute to overproduction of WIMPs or dark radiation, or violation of BBN constraints. We computemore » regions of the T{sub R} vs. m{sub 3/2} plane allowed by BBN, dark matter and dark radiation constraints for various PQ scale choices f{sub a}. These regions are compared to the values needed for thermal leptogenesis, non-thermal leptogenesis, oscillating sneutrino leptogenesis and Affleck-Dine leptogenesis. The latter three are allowed in wide regions of parameter space for PQ scale f{sub a∼} 10{sup 10}–10{sup 12} GeV which is also favored by naturalness: f{sub a} ∼ √μM{sub P}/λ{sub μ} ∼ 10{sup 10}–10{sup 12} GeV . These f{sub a} values correspond to axion masses somewhat above the projected ADMX search regions.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bae, Kyu Jung; Department of Physics, University of Tokyo,Bunkyo-ku, Tokyo 113-0033; Baer, Howard
Supersymmetric models with radiatively-driven electroweak naturalness require light higgsinos of mass ∼100–300 GeV. Naturalness in the QCD sector is invoked via the Peccei-Quinn (PQ) axion leading to mixed axion-higgsino dark matter. The SUSY DFSZ axion model provides a solution to the SUSY μ problem and the Little Hierarchy μ≪m{sub 3/2} may emerge as a consequence of a mismatch between PQ and hidden sector mass scales. The traditional gravitino problem is now augmented by the axino and saxion problems, since these latter particles can also contribute to overproduction of WIMPs or dark radiation, or violation of BBN constraints. We compute regionsmore » of the T{sub R} vs. m{sub 3/2} plane allowed by BBN, dark matter and dark radiation constraints for various PQ scale choices f{sub a}. These regions are compared to the values needed for thermal leptogenesis, non-thermal leptogenesis, oscillating sneutrino leptogenesis and Affleck-Dine leptogenesis. The latter three are allowed in wide regions of parameter space for PQ scale f{sub a}∼10{sup 10}–10{sup 12} GeV which is also favored by naturalness: f{sub a}∼√(μM{sub P}/λ{sub μ})∼10{sup 10}–10{sup 12} GeV. These f{sub a} values correspond to axion masses somewhat above the projected ADMX search regions.« less
Dark sector impact on gravitational collapse of an electrically charged scalar field
NASA Astrophysics Data System (ADS)
Nakonieczna, Anna; Rogatko, Marek; Nakonieczny, Łukasz
2015-11-01
Dark matter and dark energy are dominating components of the Universe. Their presence affects the course and results of processes, which are driven by the gravitational interaction. The objective of the paper was to examine the influence of the dark sector on the gravitational collapse of an electrically charged scalar field. A phantom scalar field was used as a model of dark energy in the system. Dark matter was modeled by a complex scalar field with a quartic potential, charged under a U(1)-gauge field. The dark components were coupled to the electrically charged scalar field via the exponential coupling and the gauge field-Maxwell field kinetic mixing, respectively. Complete non-linear simulations of the investigated process were performed. They were conducted from regular initial data to the end state, which was the matter dispersal or a singularity formation in a spacetime. During the collapse in the presence of dark energy dynamical wormholes and naked singularities were formed in emerging spacetimes. The wormhole throats were stabilized by the violation of the null energy condition, which occurred due to a significant increase of a value of the phantom scalar field function in its vicinity. The square of mass parameter of the dark matter scalar field potential controlled the formation of a Cauchy horizon or wormhole throats in the spacetime. The joint impact of dark energy and dark matter on the examined process indicated that the former decides what type of an object forms, while the latter controls the amount of time needed for the object to form. Additionally, the dark sector suppresses the natural tendency of an electrically charged scalar field to form a dynamical Reissner-Nordström spacetime during the gravitational collapse.
Generalization and capacity of extensively large two-layered perceptrons.
Rosen-Zvi, Michal; Engel, Andreas; Kanter, Ido
2002-09-01
The generalization ability and storage capacity of a treelike two-layered neural network with a number of hidden units scaling as the input dimension is examined. The mapping from the input to the hidden layer is via Boolean functions; the mapping from the hidden layer to the output is done by a perceptron. The analysis is within the replica framework where an order parameter characterizing the overlap between two networks in the combined space of Boolean functions and hidden-to-output couplings is introduced. The maximal capacity of such networks is found to scale linearly with the logarithm of the number of Boolean functions per hidden unit. The generalization process exhibits a first-order phase transition from poor to perfect learning for the case of discrete hidden-to-output couplings. The critical number of examples per input dimension, alpha(c), at which the transition occurs, again scales linearly with the logarithm of the number of Boolean functions. In the case of continuous hidden-to-output couplings, the generalization error decreases according to the same power law as for the perceptron, with the prefactor being different.
Dunin-Bell, Ola
2018-04-01
Introduction The incidence of natural disasters is increasing worldwide, with countries the least well-equipped to mitigate or manage them suffering the greatest losses. Following natural disasters, ill-prepared foreign responders may become a burden to the affected population, or cause harm to those needing help. Problem The study was performed to determine if international guidelines for foreign workers in the health sector exist, and evidence of their implementation. A structured literature search was used to identify guidelines for foreign health workers (FHWs) responding to natural disasters. Analysis of semi-structured interviews of health sector responders to the 2015 Nepal earthquake was then performed, looking at preparation and field activities. No guidelines were identified to address the appropriate qualifications of, and preparations for, international individuals participating in disaster response in the health sector. Interviews indicated individuals choosing to work with experienced organizations received training prior to disaster deployment and described activities in the field consistent with general humanitarian principles. Participants in an ad hoc team (AHT) did not. In spite of need, there is a lack of published guidelines for potential international health sector responders to natural disasters. Learning about disaster response may occur only after joining a team. Dunin-Bell O . What do they know? Guidelines and knowledge translation for foreign health sector workers following natural disasters. Prehosp Disaster Med. 2018;33(2):139-146.
Relationship between PC index and magnetospheric field-aligned currents measured by Swarm satellites
NASA Astrophysics Data System (ADS)
Troshichev, O.; Sormakov, D.; Behlke, R.
2018-03-01
The relationship between the magnetospheric field-aligned currents (FAC) monitored by the Swarm satellites and the magnetic activity PC index (which is a proxy of the solar wind energy incoming into the magnetosphere) is examined. It is shown that current intensities measured in the R1 and R2 FAC layers at the poleward and equtorward boundaries of the auroral oval are well correlated, the R2 currents being evidently secondary in relation to R1 currents and correlation in the dawn and dusk oval sectors being better than in the noon and night sectors. There is evident relationship between the PC index and the intensity of field-aligned currents in the R1 dawn and dusk layers: increase of FAC intensity in the course of substorm development is accompanied by increasing the PC index values. Correlation between PC and FAC intensities in the R2 dawn and dusk layers is also observed, but it is much weaker. No correlation is observed between PC and field-aligned currents in the midnight as well as in the noon sectors ahead of the substorm expansion phase. The results are indicative of the R1 field-aligned currents as a driver of the polar cap magnetic activity (PC index) and currents in the R2 layer.
Electrodynamic parameters in the nighttime sector during auroral substorms
NASA Technical Reports Server (NTRS)
Fujii, R.; Hoffman, R. A.; Anderson, P. C.; Craven, J. D.; Sugiura, M.; Frank, L. A.; Maynard, N. C.
1994-01-01
The characteristics of the large-scale electrodynamic parameters, field-aligned currents (FACs), electric fields, and electron precipitation, which are associated with auroral substorm events in the nighttime sector, have been obtained through a unique analysis which places the ionospheric measurements of these parameters into the context of a generic substorm determined from global auroral images. A generic bulge-type auroral emission region has been deduced from auroral images taken by the Dynamics Explorer 1 (DE 1) satellite during a number of isolated substorms, and the form has been divided into six sectors, based on the peculiar emission characteristics in each sector: west of bulge, surge horn, surge, middle surge, eastern bulge, and east of bulge. By comparing the location of passes of the Dynamics Explorer 2 (DE 2) satellite to the simultaneously obtained auroral images, each pass is placed onto the generic aurora. The organization of DE 2 data in this way has systematically clarified peculiar characteristics in the electrodynamic parameters. An upward net current mainly appears in the surge, with little net current in the surge horn and the west of bulge. The downward net current is distributed over wide longitudinal regions from the eastern bulge to the east of bulge. Near the poleward boundary of the expanding auroral bulge, a pair of oppositely directed FAC sheets is observed, with the downward FAC on the poleward side. This downward FAC and most of the upward FAC in the surge and the middle surge are assoc iated with narrow, intense antisunwqard convection, corresponding to an equatorward directed spikelike electric field. This pair of currents decreases in amplitude and latitudinal width toward dusk in the surge and the west of bulge, and the region 1 and 2 FACs become embedded in the sunward convection region. The upward FAC region associated with the spikelike field on the poleward edge of the bulge coincides well with intense electron precipitation and aurora appearing in this western and poleward protion of the bulge. The convection reversal is sharp in the west of bulge and surge horn sectors, and near the high-latitude boundary of the upward region 1, with a near stagnation region often extending over a large interval of latitude. In the eastern bulge and east of bulge sectors, the region 1 and 2 FACs are located in the sunward convection region, while a spikelike electric field occasionally appears poleward of the aurora but usually not associated with a pair of FAC sheets. In the eastern bulge, magnetic field data show complicated FAC distributions which correspond to current segments and filamentary currents.
Out of Reach, Out of Mind? Infants' Comprehension of References to Hidden Inaccessible Objects.
Osina, Maria A; Saylor, Megan M; Ganea, Patricia A
2017-09-01
This study investigated the nature of infants' difficulty understanding references to hidden inaccessible objects. Twelve-month-old infants (N = 32) responded to the mention of objects by looking at, pointing at, or approaching them when the referents were visible or accessible, but not when they were hidden and inaccessible (Experiment I). Twelve-month-olds (N = 16) responded robustly when a container with the hidden referent was moved from a previously inaccessible position to an accessible position before the request, but failed to respond when the reverse occurred (Experiment II). This suggests that infants might be able to track the hidden object's dislocations and update its accessibility as it changes. Knowing the hidden object is currently inaccessible inhibits their responding. Older, 16-month-old (N = 17) infants' performance was not affected by object accessibility. © 2016 The Authors. Child Development © 2016 Society for Research in Child Development, Inc.
Electric Potential and Electric Field Imaging with Applications
NASA Technical Reports Server (NTRS)
Generazio, Ed
2016-01-01
The technology and techniques for remote quantitative imaging of electrostatic potentials and electrostatic fields in and around objects and in free space is presented. Electric field imaging (EFI) technology may be applied to characterize intrinsic or existing electric potentials and electric fields, or an externally generated electrostatic field may be used for (illuminating) volumes to be inspected with EFI. The baseline sensor technology, electric field sensor (e-sensor), and its construction, optional electric field generation (quasistatic generator), and current e-sensor enhancements (ephemeral e-sensor) are discussed. Demonstrations for structural, electronic, human, and memory applications are shown. This new EFI capability is demonstrated to reveal characterization of electric charge distribution, creating a new field of study that embraces areas of interest including electrostatic discharge mitigation, crime scene forensics, design and materials selection for advanced sensors, dielectric morphology of structures, inspection of containers, inspection for hidden objects, tether integrity, organic molecular memory, and medical diagnostic and treatment efficacy applications such as cardiac polarization wave propagation and electromyography imaging.
State-Sponsored Tourism: A Growth Field for Public Administration?
ERIC Educational Resources Information Center
Richter, Linda K.
1985-01-01
This article explores the growth of public sector tourism development. It reports the findings of a 1984 survey of state and territorial tourism offices regarding their budgets, personnel needs, intergovernmental relations, and political support functions. The impact of public sector tourism management on public administration careers and…
New High in Engineering Degree Production. Facts
ERIC Educational Resources Information Center
Connecticut Department of Higher Education (NJ1), 2010
2010-01-01
Several of the state's key industry sectors depend heavily on employees with advanced scientific, analytic and technical knowledge. Among the fields closely related to these sectors, engineering degrees have posted the largest gain. This paper presents details on the following facts: (1) 2009 represented a record high for engineering degrees; (2)…
Entrepreneurial Mindset in Department of Defense (DoD) Organizations: Antecedents and Outcomes
2004-03-01
60 Appendix: Entrepreneurship in DoD...of behaviors based on their experience as entrepreneurs, scholars in the fields of entrepreneurship and strategic management, and consultants 2...public sector organizations; especially within DoD. Research on public sector entrepreneurship has included examinations of inventors in national
NASA Astrophysics Data System (ADS)
Smith, E. J.; Dougherty, M. K.; Zhou, X.
2010-12-01
A consensus model of Saturn’s magnetosphere that has broad acceptance consists of four regions in which the plasma and field are corotating, sub-corotating or undergoing Vasyliunas or Dungey convection. In this model, the sub-corotating magnetosphere contains a large scale circuital current system comprised of radial, field-aligned and ionospheric currents. A quantitative rendering of this system developed by S. Cowley and E. Bunch relates the azimuthal field component, B phi, that causes the field to spiral to the ionospheric Pedersen current , Ip. Cassini measurements of B phi over the four year interval between 2005 and 2008 that are widely distributed in radial distance, latitude and local time have been used to compute Ip from a Bunce-Cowley formula. A striking north-south asymmetry of the global magnetosphere has been found. In the southern hemisphere, the magnitude and variation of Ip with invariant colatitude, θ, agree qualitatively with the model but Ip (θ) is shifted poleward by about 10°. In the northern hemisphere, however, the data fail to reproduce the profile of Ip (θ) predicted by the model but are dominated by two high latitude currents having the wrong polarities. Possible causes of this asymmetry are seasonal variations (summer in the southern hemisphere) and/or asymmetric plasma outflow from the inner magnetosphere such as the plumes extending southward from Enceladus. Another finding is a significant local time dependence of Ip(θ) rather than the axisymmetry assumed in the model. There is a close correspondence with the model in the noon sector. The currents in the midnight and dawn sectors are significantly larger than in the noon sector and the current in the dusk sector is dramatically weaker.
Reflection type metasurface designed for high efficiency vectorial field generation
NASA Astrophysics Data System (ADS)
Wang, Shiyi; Zhan, Qiwen
2016-07-01
We propose a reflection type metal-insulator-metal (MIM) metasurface composed of hybrid nano-antennas for comprehensive spatial engineering of the properties of optical fields. The capability of such structure is illustrated in the design of a device that can be used to produce a radially polarized vectorial beam for optical needle field generation. This device consists of uniformly segmented sectors of high efficiency MIM metasurface. With each of the segment sector functioning as a local quarter-wave-plate (QWP), the device is designed to convert circularly polarized incidence into local linear polarization to create an overall radial polarization with corresponding binary phases and extremely high dynamic range amplitude modulation. The capability of such devices enables the generation of nearly arbitrarily complex optical fields that may find broad applications that transcend disciplinary boundaries.
Ising versus S U (2) 2 string-net ladder
NASA Astrophysics Data System (ADS)
Vidal, Julien
2018-03-01
We consider the string-net model obtained from S U (2) 2 fusion rules. These fusion rules are shared by two different sets of anyon theories. In this paper, we study the competition between the two corresponding non-Abelian quantum phases in the ladder geometry. A detailed symmetry analysis shows that the nontrivial low-energy sector corresponds to the transverse-field cluster model that displays a critical point described by the s o (2) 1 conformal field theory. Other sectors are obtained by freezing spins in this model.
NASA Astrophysics Data System (ADS)
Ioannis, Seimenis; Damianos, Sakas P.; Nikolaos, Konstantopoulos
2009-08-01
This article examines the factors that affect the decision making of the training managers responsible in case of business communication field as they have emerged from the study of the decision that have taken place in the commercial sector in this specific Greek market. Previous researches have indicated the participation of a number of variables in this kind of decision. The aim of this article is to locate the main factors which determine, in the commercial sector the decision for the training of the employees in the field of business communication. On the basis of quality research, dynamic simulation model have been created for some of this main factors.
NASA Astrophysics Data System (ADS)
Schoess, Jeffrey N.; Seifert, Greg; Paul, Clare A.
1996-05-01
The smart aircraft fastener evaluation (SAFE) system is an advanced structural health monitoring effort to detect and characterize corrosion in hidden and inaccessible locations of aircraft structures. Hidden corrosion is the number one logistics problem for the U.S. Air Force, with an estimated maintenance cost of $700M per year in 1990 dollars. The SAFE system incorporates a solid-state electrochemical microsensor and smart sensor electronics in the body of a Hi-Lok aircraft fastener to process and autonomously report corrosion status to aircraft maintenance personnel. The long-term payoff for using SAFE technology will be in predictive maintenance for aging aircraft and rotorcraft systems, fugitive emissions applications such as control valves, chemical pipeline vessels, and industrial boilers. Predictive maintenance capability, service, and repair will replace the current practice of scheduled maintenance to substantially reduce operational costs. A summary of the SAFE concept, laboratory test results, and future field test plans is presented.
Ito, Sosuke
2016-01-01
The transfer entropy is a well-established measure of information flow, which quantifies directed influence between two stochastic time series and has been shown to be useful in a variety fields of science. Here we introduce the transfer entropy of the backward time series called the backward transfer entropy, and show that the backward transfer entropy quantifies how far it is from dynamics to a hidden Markov model. Furthermore, we discuss physical interpretations of the backward transfer entropy in completely different settings of thermodynamics for information processing and the gambling with side information. In both settings of thermodynamics and the gambling, the backward transfer entropy characterizes a possible loss of some benefit, where the conventional transfer entropy characterizes a possible benefit. Our result implies the deep connection between thermodynamics and the gambling in the presence of information flow, and that the backward transfer entropy would be useful as a novel measure of information flow in nonequilibrium thermodynamics, biochemical sciences, economics and statistics. PMID:27833120
NASA Astrophysics Data System (ADS)
Ito, Sosuke
2016-11-01
The transfer entropy is a well-established measure of information flow, which quantifies directed influence between two stochastic time series and has been shown to be useful in a variety fields of science. Here we introduce the transfer entropy of the backward time series called the backward transfer entropy, and show that the backward transfer entropy quantifies how far it is from dynamics to a hidden Markov model. Furthermore, we discuss physical interpretations of the backward transfer entropy in completely different settings of thermodynamics for information processing and the gambling with side information. In both settings of thermodynamics and the gambling, the backward transfer entropy characterizes a possible loss of some benefit, where the conventional transfer entropy characterizes a possible benefit. Our result implies the deep connection between thermodynamics and the gambling in the presence of information flow, and that the backward transfer entropy would be useful as a novel measure of information flow in nonequilibrium thermodynamics, biochemical sciences, economics and statistics.
NASA Astrophysics Data System (ADS)
Zhang, Wei; Jiang, Ling; Han, Lei
2018-04-01
Convective storm nowcasting refers to the prediction of the convective weather initiation, development, and decay in a very short term (typically 0 2 h) .Despite marked progress over the past years, severe convective storm nowcasting still remains a challenge. With the boom of machine learning, it has been well applied in various fields, especially convolutional neural network (CNN). In this paper, we build a servere convective weather nowcasting system based on CNN and hidden Markov model (HMM) using reanalysis meteorological data. The goal of convective storm nowcasting is to predict if there is a convective storm in 30min. In this paper, we compress the VDRAS reanalysis data to low-dimensional data by CNN as the observation vector of HMM, then obtain the development trend of strong convective weather in the form of time series. It shows that, our method can extract robust features without any artificial selection of features, and can capture the development trend of strong convective storm.
Analyzing Hidden Semantics in Social Bookmarking of Open Educational Resources
NASA Astrophysics Data System (ADS)
Minguillón, Julià
Web 2.0 services such as social bookmarking allow users to manage and share the links they find interesting, adding their own tags for describing them. This is especially interesting in the field of open educational resources, as delicious is a simple way to bridge the institutional point of view (i.e. learning object repositories) with the individual one (i.e. personal collections), thus promoting the discovering and sharing of such resources by other users. In this paper we propose a methodology for analyzing such tags in order to discover hidden semantics (i.e. taxonomies and vocabularies) that can be used to improve descriptions of learning objects and make learning object repositories more visible and discoverable. We propose the use of a simple statistical analysis tool such as principal component analysis to discover which tags create clusters that can be semantically interpreted. We will compare the obtained results with a collection of resources related to open educational resources, in order to better understand the real needs of people searching for open educational resources.
NASA Astrophysics Data System (ADS)
Xiong, Yan; Reichenbach, Stephen E.
1999-01-01
Understanding of hand-written Chinese characters is at such a primitive stage that models include some assumptions about hand-written Chinese characters that are simply false. So Maximum Likelihood Estimation (MLE) may not be an optimal method for hand-written Chinese characters recognition. This concern motivates the research effort to consider alternative criteria. Maximum Mutual Information Estimation (MMIE) is an alternative method for parameter estimation that does not derive its rationale from presumed model correctness, but instead examines the pattern-modeling problem in automatic recognition system from an information- theoretic point of view. The objective of MMIE is to find a set of parameters in such that the resultant model allows the system to derive from the observed data as much information as possible about the class. We consider MMIE for recognition of hand-written Chinese characters using on a simplified hidden Markov Random Field. MMIE provides improved performance improvement over MLE in this application.
Passive acoustic leak detection for sodium cooled fast reactors using hidden Markov models
DOE Office of Scientific and Technical Information (OSTI.GOV)
Riber Marklund, A.; Kishore, S.; Prakash, V.
2015-07-01
Acoustic leak detection for steam generators of sodium fast reactors have been an active research topic since the early 1970's and several methods have been tested over the years. Inspired by its success in the field of automatic speech recognition, we here apply hidden Markov models (HMM) in combination with Gaussian mixture models (GMM) to the problem. To achieve this, we propose a new feature calculation scheme, based on the temporal evolution of the power spectral density (PSD) of the signal. Using acoustic signals recorded during steam/water injection experiments done at the Indira Gandhi Centre for Atomic Research (IGCAR), themore » proposed method is tested. We perform parametric studies on the HMM+GMM model size and demonstrate that the proposed method a) performs well without a priori knowledge of injection noise, b) can incorporate several noise models and c) has an output distribution that simplifies false alarm rate control. (authors)« less
Cross-modal learning to rank via latent joint representation.
Wu, Fei; Jiang, Xinyang; Li, Xi; Tang, Siliang; Lu, Weiming; Zhang, Zhongfei; Zhuang, Yueting
2015-05-01
Cross-modal ranking is a research topic that is imperative to many applications involving multimodal data. Discovering a joint representation for multimodal data and learning a ranking function are essential in order to boost the cross-media retrieval (i.e., image-query-text or text-query-image). In this paper, we propose an approach to discover the latent joint representation of pairs of multimodal data (e.g., pairs of an image query and a text document) via a conditional random field and structural learning in a listwise ranking manner. We call this approach cross-modal learning to rank via latent joint representation (CML²R). In CML²R, the correlations between multimodal data are captured in terms of their sharing hidden variables (e.g., topics), and a hidden-topic-driven discriminative ranking function is learned in a listwise ranking manner. The experiments show that the proposed approach achieves a good performance in cross-media retrieval and meanwhile has the capability to learn the discriminative representation of multimodal data.
Van Woerkom, Craig; Ferrucci, Steven
2005-05-01
Retinitis pigmentosa (RP) is one of the most common hereditary retinal dystrophies and causes of visual impairment affecting all age groups. The reported incidence varies, but is considered to be between 1 in 3,000 to 1 in 7,000. Sector retinitis pigmentosa is an atypical form of RP that is characterized by regionalized areas of bone spicule pigmentation, usually in the inferior quadrants of the retina. A 57-year-old Hispanic man with a history of previously diagnosed retinitis pigmentosa came to the clinic with a longstanding symptom of decreased vision at night. Bone spicule pigmentation was found in the nasal and inferior quadrants in each eye. He demonstrated superior and temporal visual-field loss corresponding to the areas of the affected retina. Clinical measurements of visual-field loss, best-corrected visual acuity, and ophthalmoscopic appearance have remained stable during the five years the patient has been followed. Sector retinitis pigmentosa is an atypical form of RP that is characterized by bilateral pigmentary retinopathy, usually isolated to the inferior quadrants. The remainder of the retina appears clinically normal, although studies have found functional abnormalities in these areas as well. Sector RP is generally considered a stationary to slowly progressive disease, with subnormal electro-retinogram findings and visual-field defects corresponding to the involved retinal sectors. Management of RP is very difficult because there are no proven methods of treatment. Studies have shown 15,000 IU of vitamin A palmitate per day may slow the progression, though this result is controversial. Low vision rehabilitation, long wavelength pass filters, and pedigree counseling remain the mainstay of management.
Detection of hidden explosives in different scenarios with the use of nuclear probes
NASA Astrophysics Data System (ADS)
Nebbia, G.; Pesente, S.; Lunardon, M.; Moretto, S.; Viesti, G.; Cinausero, M.; Barbui, M.; Fioretto, E.; Filippini, V.; Sudac, D.; Nađ, K.; Blagus, S.; Valković, V.
2005-04-01
The detection of landmines by using available technologies is a time consuming, expensive and extremely dangerous job, so that there is a need for a technological breakthrough in this field. Atomic and nuclear physics based sensors might offer new possibilities in de-mining. Technology and methods derived from the studies applied to the detection of landmines can be successfully applied to the screening of cargo in customs inspections.
Parallel Electric Field on Auroral Magnetic Field Lines.
NASA Astrophysics Data System (ADS)
Yeh, Huey-Ching Betty
1982-03-01
The interaction of Birkeland (magnetic-field-aligned) current carriers and the Earth's magnetic field results in electrostatic potential drops along magnetic field lines. The statistical distributions of the field-aligned potential difference (phi)(,(PARLL)) were determined from the energy spectra of electron inverted "V" events observed at ionospheric altitude for different conditions of geomagnetic activity as indicated by the AE index. Data of 1270 electron inverted "V"'s were obtained from Low-Energy Electron measurements of the Atmosphere Explorer-C and -D Satellite (despun mode) in the interval January 1974-April 1976. In general, (phi)(,(PARLL)) is largest in the dusk to pre-midnight sector, smaller in the post-midnight to dawn sector, and smallest in the near noon sector during quiet and disturbed geomagnetic conditions; there is a steady dusk-dawn-noon asymmetry of the global (phi)(,(PARLL)) distribution. As the geomagnetic activity level increases, the (phi)(,(PARLL)) pattern expands to lower invariant latitudes, and the magnitude of (phi)(,(PARLL)) in the 13-24 magnetic local time sector increases significantly. The spatial structure and intensity variation of the global (phi)(,(PARLL)) distribution are statistically more variable, and the magnitudes of (phi)(,(PARLL)) have smaller correlation with the AE-index, in the post-midnight to dawn sector. A strong correlation is found to exist between upward Birkeland current systems and global parallel potential drops, and between auroral electron precipitation patterns and parallel potential drops, regarding their mophology, their intensity and their dependence of geomagnetic activity. An analysis of the fine-scale simultaneous current-voltage relationship for upward Birkeland currents in Region 1 shows that typical field-aligned potential drops are consistent with model predictions based on linear acceleration of the charge carriers through an electrostatic potential drop along convergent magnetic field lines to maintain current continuity. In a steady state, this model of simple electrostatic acceleration without anomalous resistivity also predicts observable relations between global parallel currents and parallel potential drops and between global energy deposition and parallel potential drops. The temperature, density, and species of the unaccelerated charge carriers are the relevant parameters of the model. The dusk-dawn -noon asymmetry of the global (phi)(,(PARLL)) distribution can be explained by the above steady-state (phi)(,(PARLL)) process if we associate the source regions of upward Birkeland current carriers in Region 1, Region 2, and the cusp region with the plasma sheet boundary layer, the near-Earth plasma sheet, and the magnetosheath, respectively. The results of this study provide observational information on the global distribution of parallel potential drops and the prevailing process of generating and maintaining potential gradients (parallel electric fields) along auroral magnetic field lines.
Critical reflections on methodological challenge in arts and dementia evaluation and research.
Gray, Karen; Evans, Simon Chester; Griffiths, Amanda; Schneider, Justine
2017-01-01
Methodological rigour, or its absence, is often a focus of concern for the emerging field of evaluation and research around arts and dementia. However, this paper suggests that critical attention should also be paid to the way in which individual perceptions, hidden assumptions and underlying social and political structures influence methodological work in the field. Such attention will be particularly important for addressing methodological challenges relating to contextual variability, ethics, value judgement and signification identified through a literature review on this topic. Understanding how, where and when evaluators and researchers experience such challenges may help to identify fruitful approaches for future evaluation.
NASA Astrophysics Data System (ADS)
Jimbo, Michio
2013-03-01
Since the beginning of 1980s, hidden infinite dimensional symmetries have emerged as the origin of integrability: first in soliton theory and then in conformal field theory. Quest for symmetries in quantum integrable models has led to the discovery of quantum groups. On one hand this opened up rapid mathematical developments in representation theory, combinatorics and other fields. On the other hand it has advanced understanding of correlation functions of lattice models, leading to multiple integral formulas in integrable spin chains. We shall review these developments which continue up to the present time.
Compacted dimensions and singular plasmonic surfaces.
Pendry, J B; Huidobro, Paloma Arroyo; Luo, Yu; Galiffi, Emanuele
2017-11-17
In advanced field theories, there can be more than four dimensions to space, the excess dimensions described as compacted and unobservable on everyday length scales. We report a simple model, unconnected to field theory, for a compacted dimension realized in a metallic metasurface periodically structured in the form of a grating comprising a series of singularities. An extra dimension of the grating is hidden, and the surface plasmon excitations, though localized at the surface, are characterized by three wave vectors rather than the two of typical two-dimensional metal grating. We propose an experimental realization in a doped graphene layer. Copyright © 2017, American Association for the Advancement of Science.
NASA Technical Reports Server (NTRS)
Mendillo, M.; He, X.-Q.; Rishbeth, H.
1992-01-01
The effects of thermospheric winds and electric fields on the ionospheric F2-layer are controlled by the geometry of the magnetic field, and so vary with latitude and longitude. A simple model of the daytime F2-layer is adopted and the effects at midlatitudes (25-65 deg geographic) of three processes that accompany geomagnetic storms: (1) thermospheric changes due to auroral heating; (2) equatorward winds that tend to cancel the quiet-day poleward winds; and (3) the penetration of magnetospheric electric fields are studied. At +/- 65 deg, the effects of heating and electric fields are strongest in the longitudes toward which the geomagnetic dipole is tilted, i.e., the North American and the South Indian Ocean sectors. Because of the proximity of the geomagnetic equator to the East Asian and South American sectors, the reverse is true at +/- 25 deg.
Holographic vortices in the presence of dark matter sector
NASA Astrophysics Data System (ADS)
Rogatko, Marek; Wysokinski, Karol I.
2015-12-01
The dark matter seem to be an inevitable ingredient of the total matter configuration in the Universe and the knowledge how the dark matter affects the properties of superconductors is of vital importance for the experiments aimed at its direct detection. The homogeneous magnetic field acting perpendicularly to the surface of (2+1) dimensional s-wave holographic superconductor in the theory with dark matter sector has been modeled by the additional U(1)-gauge field representing dark matter and coupled to the Maxwell one. As expected the free energy for the vortex configuration turns out to be negative. Importantly its value is lower in the presence of dark matter sector. This feature can explain why in the Early Universe first the web of dark matter appeared and next on these gratings the ordinary matter forming cluster of galaxies has formed.
Life imitating art: depictions of the hidden curriculum in medical television programs.
Stanek, Agatha; Clarkin, Chantalle; Bould, M Dylan; Writer, Hilary; Doja, Asif
2015-09-26
The hidden curriculum represents influences occurring within the culture of medicine that indirectly alter medical professionals' interactions, beliefs and clinical practices throughout their training. One approach to increase medical student awareness of the hidden curriculum is to provide them with readily available examples of how it is enacted in medicine; as such the purpose of this study was to examine depictions of the hidden curriculum in popular medical television programs. One full season of ER, Grey's Anatomy and Scrubs were selected for review. A summative content analysis was performed to ascertain the presence of depictions of the hidden curriculum, as well as to record the type, frequency and quality of examples. A second reviewer also viewed a random selection of episodes from each series to establish coding reliability. The most prevalent themes across all television programs were: the hierarchical nature of medicine; challenges during transitional stages in medicine; the importance of role modeling; patient dehumanization; faking or overstating one's capabilities; unprofessionalism; the loss of idealism; and difficulties with work-life balance. The hidden curriculum is frequently depicted in popular medical television shows. These examples of the hidden curriculum could serve as a valuable teaching resource in undergraduate medical programs.
Uncovering hidden nodes in complex networks in the presence of noise
Su, Ri-Qi; Lai, Ying-Cheng; Wang, Xiao; Do, Younghae
2014-01-01
Ascertaining the existence of hidden objects in a complex system, objects that cannot be observed from the external world, not only is curiosity-driven but also has significant practical applications. Generally, uncovering a hidden node in a complex network requires successful identification of its neighboring nodes, but a challenge is to differentiate its effects from those of noise. We develop a completely data-driven, compressive-sensing based method to address this issue by utilizing complex weighted networks with continuous-time oscillatory or discrete-time evolutionary-game dynamics. For any node, compressive sensing enables accurate reconstruction of the dynamical equations and coupling functions, provided that time series from this node and all its neighbors are available. For a neighboring node of the hidden node, this condition cannot be met, resulting in abnormally large prediction errors that, counterintuitively, can be used to infer the existence of the hidden node. Based on the principle of differential signal, we demonstrate that, when strong noise is present, insofar as at least two neighboring nodes of the hidden node are subject to weak background noise only, unequivocal identification of the hidden node can be achieved. PMID:24487720
The promises of big data and small data for travel behavior (aka human mobility) analysis.
Chen, Cynthia; Ma, Jingtao; Susilo, Yusak; Liu, Yu; Wang, Menglin
2016-07-01
The last decade has witnessed very active development in two broad, but separate fields, both involving understanding and modeling of how individuals move in time and space (hereafter called "travel behavior analysis" or "human mobility analysis"). One field comprises transportation researchers who have been working in the field for decades and the other involves new comers from a wide range of disciplines, but primarily computer scientists and physicists. Researchers in these two fields work with different datasets, apply different methodologies, and answer different but overlapping questions. It is our view that there is much, hidden synergy between the two fields that needs to be brought out. It is thus the purpose of this paper to introduce datasets, concepts, knowledge and methods used in these two fields, and most importantly raise cross-discipline ideas for conversations and collaborations between the two. It is our hope that this paper will stimulate many future cross-cutting studies that involve researchers from both fields.
The promises of big data and small data for travel behavior (aka human mobility) analysis
Chen, Cynthia; Ma, Jingtao; Susilo, Yusak; Liu, Yu; Wang, Menglin
2016-01-01
The last decade has witnessed very active development in two broad, but separate fields, both involving understanding and modeling of how individuals move in time and space (hereafter called “travel behavior analysis” or “human mobility analysis”). One field comprises transportation researchers who have been working in the field for decades and the other involves new comers from a wide range of disciplines, but primarily computer scientists and physicists. Researchers in these two fields work with different datasets, apply different methodologies, and answer different but overlapping questions. It is our view that there is much, hidden synergy between the two fields that needs to be brought out. It is thus the purpose of this paper to introduce datasets, concepts, knowledge and methods used in these two fields, and most importantly raise cross-discipline ideas for conversations and collaborations between the two. It is our hope that this paper will stimulate many future cross-cutting studies that involve researchers from both fields. PMID:27182125
Penetration of Large Scale Electric Field to Inner Magnetosphere
NASA Astrophysics Data System (ADS)
Chen, S. H.; Fok, M. C. H.; Sibeck, D. G.; Wygant, J. R.; Spence, H. E.; Larsen, B.; Reeves, G. D.; Funsten, H. O.
2015-12-01
The direct penetration of large scale global electric field to the inner magnetosphere is a critical element in controlling how the background thermal plasma populates within the radiation belts. These plasma populations provide the source of particles and free energy needed for the generation and growth of various plasma waves that, at critical points of resonances in time and phase space, can scatter or energize radiation belt particles to regulate the flux level of the relativistic electrons in the system. At high geomagnetic activity levels, the distribution of large scale electric fields serves as an important indicator of how prevalence of strong wave-particle interactions extend over local times and radial distances. To understand the complex relationship between the global electric fields and thermal plasmas, particularly due to the ionospheric dynamo and the magnetospheric convection effects, and their relations to the geomagnetic activities, we analyze the electric field and cold plasma measurements from Van Allen Probes over more than two years period and simulate a geomagnetic storm event using Coupled Inner Magnetosphere-Ionosphere Model (CIMI). Our statistical analysis of the measurements from Van Allan Probes and CIMI simulations of the March 17, 2013 storm event indicate that: (1) Global dawn-dusk electric field can penetrate the inner magnetosphere inside the inner belt below L~2. (2) Stronger convections occurred in the dusk and midnight sectors than those in the noon and dawn sectors. (3) Strong convections at multiple locations exist at all activity levels but more complex at higher activity levels. (4) At the high activity levels, strongest convections occur in the midnight sectors at larger distances from the Earth and in the dusk sector at closer distances. (5) Two plasma populations of distinct ion temperature isotropies divided at L-Shell ~2, indicating distinct heating mechanisms between inner and outer radiation belts. (6) CIMI simulations reveal alternating penetration and shielding electric fields during the main phase of the geomagnetic storm, indicating an impulsive nature of the large scale penetrating electric field in regulating the gain and loss of radiation belt particles. We will present the statistical analysis and simulations results.
The Politics of the Hidden Curriculum
ERIC Educational Resources Information Center
Giroux, Henry A.
1977-01-01
Schools teach much more than the traditional curriculum. They also teach a "hidden curriculum"--those unstated norms, values, and beliefs promoting hierarchic and authoritarian social relations that are transmitted to students through the underlying educational structure. Discusses the effects of the "hidden curriculum" on the…
Birefringence and hidden photons
NASA Astrophysics Data System (ADS)
Arza, Ariel; Gamboa, J.
2018-05-01
We study a model where photons interact with hidden photons and millicharged particles through a kinetic mixing term. Particularly, we focus on vacuum birefringence effects and we find a bound for the millicharged parameter assuming that hidden photons are a piece of the local dark matter density.
Geophysical Investigations at Hidden Dam, Raymond, California Flow Simulations
Minsley, Burke J.; Ikard, Scott
2010-01-01
Numerical flow modeling and analysis of observation-well data at Hidden Dam are carried out to supplement recent geophysical field investigations at the site (Minsley and others, 2010). This work also is complementary to earlier seepage-related studies at Hidden Dam documented by Cedergren (1980a, b). Known seepage areas on the northwest right abutment area of the downstream side of the dam was documented by Cedergren (1980a, b). Subsequent to the 1980 seepage study, a drainage blanket with a sub-drain system was installed to mitigate downstream seepage. Flow net analysis provided by Cedergren (1980a, b) suggests that the primary seepage mechanism involves flow through the dam foundation due to normal reservoir pool elevations, which results in upflow that intersects the ground surface in several areas on the downstream side of the dam. In addition to the reservoir pool elevations and downstream surface topography, flow is also controlled by the existing foundation geology as well as the presence or absence of a horizontal drain in the downstream portion of the dam. The current modeling study is aimed at quantifying how variability in dam and foundation hydrologic properties influences seepage as a function of reservoir stage. Flow modeling is implemented using the COMSOL Multiphysics software package, which solves the partially saturated flow equations in a two-dimensional (2D) cross-section of Hidden Dam that also incorporates true downstream topography. Use of the COMSOL software package provides a more quantitative approach than the flow net analysis by Cedergren (1980a, b), and allows for rapid evaluation of the influence of various parameters such as reservoir level, dam structure and geometry, and hydrogeologic properties of the dam and foundation materials. Historical observation-well data are used to help validate the flow simulations by comparing observed and predicted water levels for a range of reservoir elevations. The flow models are guided by, and discussed in the context of, the geophysical work (Minsley and others, 2010) where appropriate.
Mean-field theory of baryonic matter for QCD in the large Nc and heavy quark mass limits
NASA Astrophysics Data System (ADS)
Adhikari, Prabal; Cohen, Thomas D.
2013-11-01
We discuss theoretical issues pertaining to baryonic matter in the combined heavy-quark and large Nc limits of QCD. Witten's classic argument that baryons and interacting systems of baryons can be described in a mean-field approximation with each of the quarks moving in an average potential due to the remaining quarks is heuristic. It is important to justify this heuristic description for the case of baryonic matter since systems of interacting baryons are intrinsically more complicated than single baryons due to the possibility of hidden color states—states in which the subsystems making up the entire baryon crystal are not color-singlet nucleons but rather colorful states coupled together to make a color-singlet state. In this work, we provide a formal justification of this heuristic prescription. In order to do this, we start by taking the heavy quark limit, thus effectively reducing the problem to a many-body quantum mechanical system. This problem can be formulated in terms of integrals over coherent states, which for this problem are simple Slater determinants. We show that for the many-body problem, the support region for these integrals becomes narrow at large Nc, yielding an energy which is well approximated by a single coherent state—that is a mean-field description. Corrections to the energy are of relative order 1/Nc. While hidden color states are present in the exact state of the heavy quark system, they only influence the interaction energy below leading order in 1/Nc.
Sparkman, Amanda M; Chism, Kenneth R; Bronikowski, Anne M; Brummett, Lilly J; Combrink, Lucia L; Davis, Courtney L; Holden, Kaitlyn G; Kabey, Nicole M; Miller, David A W
2018-03-01
A thorough understanding of the life cycles underlying the demography of wild species is limited by the difficulty of observing hidden life-history traits, such as embryonic development. Major aspects of embryonic development, such as the rate and timing of development, and maternal-fetal interactions can be critical features of early-life fitness and may impact population trends via effects on individual survival. While information on development in wild snakes and lizards is particularly limited, the repeated evolution of viviparity and diversity of reproductive mode in this clade make it a valuable subject of study. We used field-portable ultrasonography to investigate embryonic development in two sympatric garter snake species, Thamnophis sirtalis and Thamnophis elegans in the Sierra Nevada mountains of California. This approach allowed us to examine previously hidden reproductive traits including the timing and annual variation in development and differences in parental investment in young. Both species are viviparous, occupy similar ecological niches, and experience the same annual environmental conditions. We found that T. sirtalis embryos were more developmentally advanced than T. elegans embryos during June of three consecutive years. We also found that eggs increased in volume more substantially across developmental stages in T. elegans than in T. sirtalis , indicating differences in maternal provisioning of embryos via placental transfer of water. These findings shed light on interspecific differences in parental investment and timing of development within the same environmental context and demonstrate the value of field ultrasonography for pursuing questions relating to the evolution of reproductive modes, and the ecology of development.
Scott, Stephanie; Shucksmith, Janet; Baker, Rachel; Kaner, Eileen
2017-06-08
This study explored mid-adolescents' views and experiences of socio-ecological influences on their drinking practices in order to help inform the development of interventions to reduce alcohol-related risk. We conducted 31 in-depth interviews with young people aged 13-17 in North East England. Verbatim interview transcripts and field notes were coded systematically and analysed thematically, following the principles of constant comparison. We adopted Bourdieu's idea of social game-playing and elements of his conceptual toolkit (particularly habitus, capital and field) during analysis. Analysis yielded three intersecting themes: (1) 'drinking etiquette': conveying taste and disgust; (2) 'playing the drinking game': demonstrating cultural competency; (3) 'hidden habitus'-the role of alcohol marketing. Our work demonstrates that there is a nexus of influential factors which come together to help shape and reinforce mid-adolescents' behaviour, norms and values in relation to alcohol consumption. Drinking practices are not just formed by friendships and family traditions, these are also subject to wider cultural shaping including by the alcohol industry which can encourage brand identification, and gear specific products to add 'distinction'. However young people are not inactive players and they use aspects of capital and social games to help cement their identity and present themselves in particular ways which in turn are influenced by age, gender and social status. Guided by promising work in the tobacco field, interventions which focus on critical awareness of the framing of alcohol products by key stakeholders, such as policymakers, commercial industry and public health professionals, and by wider society may facilitate behaviour change among young people.
San Francisco Bay Area Environmental Education Needs Study.
ERIC Educational Resources Information Center
Fish, Duane
To identify environmental technician positions in the public and private sectors of the San Francisco Bay Area as well as to determine the skills and knowledge necessary for employment in the field, questionnaires were distributed to companies, agencies, individuals of the private sector in the area, and 33 institutions offering an Occupational…
Reframing Curriculum and Pedagogical Discourse in Universities of Technology
ERIC Educational Resources Information Center
Ntshoe, I.
2012-01-01
This articles aims to demystify curriculum and pedagogical discourses and related practices of sectoral occupational fields and qualifications of universities of technology (UoTs). The article takes issue with the academic tradition which emphasises distinctiveness of UoT as a sector that should focus exclusively on applied knowledge that is fixed…
Climatology of the inter-hemispheric field-aligned currents system over the Nigeria ionosphere
NASA Astrophysics Data System (ADS)
Bolaji, O. S.; Rabiu, A. B.; Oyeyemi, E. O.; Yumoto, K.
2012-11-01
Records of the declination (D) magnetic field data for the year 2009 from the Magnetic Data Acquisition System (MAGDAS) facilities at University of Ilorin were employed for this work. From the minutes value of the D-component, the deduced hourly values of the D-component (Sq(QD)) were used to estimate its diurnal (Sq(D)) values with the most five quietest days identified. The monthly mean (MSq(D)) of the most five quietest days and their seasonal (SSq(D)) variabilities were investigated. The inter-hemispheric field aligned currents (IHFACs) exhibit downward and upward inter-hemispheric field-aligned sheet current that appears as a pair at all local times of the Sq(D), MSq(D), and SSq(D) variations. From these variabilities, the IHFACs were observed to flow from the winter to summer hemisphere during noon and dusk sector and flowing in opposite direction during the dawn sector. The Sq(D) variability patterns that were observed in May, June, August September are gentle compared to the disturbed variabilities in January, February, March and November. The highest positive (˜1.7 arc-min) and negative (˜-2.7 arc min) MSq(D) maxima values were observed in August during the dawn and noon sectors respectively. These values indicated that the IHFACs flow in August is strongly southbound (positive) and northbound (negative) in the dawn and noon sectors respectively. Dusk-side IHFACs as can be observed by MAGDAS are weakly northbound in all the seasons. The direction of IHFACs does not flip at the equinoxes but in June and November and does not become largest at solstices but in August. The IHFACs was observed to exhibit longitudinal variability, which indicated that larger amplitude of winter-to-summer IHFACs is observed to be greater in June solstice (northbound/negative IHFACs) than in the December solstice (southbound/positive IHFACs) during the noon sector.
Implications of the measured angular anisotropy at the hidden order transition of URu2Si2
NASA Astrophysics Data System (ADS)
Chandra, P.; Coleman, P.; Flint, R.; Trinh, J.; Ramirez, A. P.
2018-05-01
The heavy fermion compound URu2Si2 continues to attract great interest due to the long-unidentified nature of the hidden order that develops below 17.5 K. Here we discuss the implications of an angular survey of the linear and nonlinear susceptibility of URu2Si2 in the vicinity of the hidden order transition [1]. While the anisotropic nature of spin fluctuations and low-temperature quasiparticles was previously established, our recent results suggest that the order parameter itself has intrinsic Ising anisotropy, and that moreover this anisotropy extends far above the hidden order transition. Consistency checks and subsequent questions for future experimental and theoretical studies of hidden order are discussed.